1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 */
8#ifndef _UAPI__LINUX_BPF_H__
9#define _UAPI__LINUX_BPF_H__
10
11#include <linux/types.h>
12#include <linux/bpf_common.h>
13
14/* Extended instruction set based on top of classic BPF */
15
16/* instruction classes */
17#define BPF_JMP32	0x06	/* jmp mode in word width */
18#define BPF_ALU64	0x07	/* alu mode in double word width */
19
20/* ld/ldx fields */
21#define BPF_DW		0x18	/* double word (64-bit) */
22#define BPF_ATOMIC	0xc0	/* atomic memory ops - op type in immediate */
23#define BPF_XADD	0xc0	/* exclusive add - legacy name */
24
25/* alu/jmp fields */
26#define BPF_MOV		0xb0	/* mov reg to reg */
27#define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
28
29/* change endianness of a register */
30#define BPF_END		0xd0	/* flags for endianness conversion: */
31#define BPF_TO_LE	0x00	/* convert to little-endian */
32#define BPF_TO_BE	0x08	/* convert to big-endian */
33#define BPF_FROM_LE	BPF_TO_LE
34#define BPF_FROM_BE	BPF_TO_BE
35
36/* jmp encodings */
37#define BPF_JNE		0x50	/* jump != */
38#define BPF_JLT		0xa0	/* LT is unsigned, '<' */
39#define BPF_JLE		0xb0	/* LE is unsigned, '<=' */
40#define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
41#define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
42#define BPF_JSLT	0xc0	/* SLT is signed, '<' */
43#define BPF_JSLE	0xd0	/* SLE is signed, '<=' */
44#define BPF_CALL	0x80	/* function call */
45#define BPF_EXIT	0x90	/* function return */
46
47/* atomic op type fields (stored in immediate) */
48#define BPF_FETCH	0x01	/* not an opcode on its own, used to build others */
49#define BPF_XCHG	(0xe0 | BPF_FETCH)	/* atomic exchange */
50#define BPF_CMPXCHG	(0xf0 | BPF_FETCH)	/* atomic compare-and-write */
51
52/* Register numbers */
53enum {
54	BPF_REG_0 = 0,
55	BPF_REG_1,
56	BPF_REG_2,
57	BPF_REG_3,
58	BPF_REG_4,
59	BPF_REG_5,
60	BPF_REG_6,
61	BPF_REG_7,
62	BPF_REG_8,
63	BPF_REG_9,
64	BPF_REG_10,
65	__MAX_BPF_REG,
66};
67
68/* BPF has 10 general purpose 64-bit registers and stack frame. */
69#define MAX_BPF_REG	__MAX_BPF_REG
70
71struct bpf_insn {
72	__u8	code;		/* opcode */
73	__u8	dst_reg:4;	/* dest register */
74	__u8	src_reg:4;	/* source register */
75	__s16	off;		/* signed offset */
76	__s32	imm;		/* signed immediate constant */
77};
78
79/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
80struct bpf_lpm_trie_key {
81	__u32	prefixlen;	/* up to 32 for AF_INET, 128 for AF_INET6 */
82	__u8	data[0];	/* Arbitrary size */
83};
84
85struct bpf_cgroup_storage_key {
86	__u64	cgroup_inode_id;	/* cgroup inode id */
87	__u32	attach_type;		/* program attach type (enum bpf_attach_type) */
88};
89
90enum bpf_cgroup_iter_order {
91	BPF_CGROUP_ITER_ORDER_UNSPEC = 0,
92	BPF_CGROUP_ITER_SELF_ONLY,		/* process only a single object. */
93	BPF_CGROUP_ITER_DESCENDANTS_PRE,	/* walk descendants in pre-order. */
94	BPF_CGROUP_ITER_DESCENDANTS_POST,	/* walk descendants in post-order. */
95	BPF_CGROUP_ITER_ANCESTORS_UP,		/* walk ancestors upward. */
96};
97
98union bpf_iter_link_info {
99	struct {
100		__u32	map_fd;
101	} map;
102	struct {
103		enum bpf_cgroup_iter_order order;
104
105		/* At most one of cgroup_fd and cgroup_id can be non-zero. If
106		 * both are zero, the walk starts from the default cgroup v2
107		 * root. For walking v1 hierarchy, one should always explicitly
108		 * specify cgroup_fd.
109		 */
110		__u32	cgroup_fd;
111		__u64	cgroup_id;
112	} cgroup;
113	/* Parameters of task iterators. */
114	struct {
115		__u32	tid;
116		__u32	pid;
117		__u32	pid_fd;
118	} task;
119};
120
121/* BPF syscall commands, see bpf(2) man-page for more details. */
122/**
123 * DOC: eBPF Syscall Preamble
124 *
125 * The operation to be performed by the **bpf**\ () system call is determined
126 * by the *cmd* argument. Each operation takes an accompanying argument,
127 * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
128 * below). The size argument is the size of the union pointed to by *attr*.
129 */
130/**
131 * DOC: eBPF Syscall Commands
132 *
133 * BPF_MAP_CREATE
134 *	Description
135 *		Create a map and return a file descriptor that refers to the
136 *		map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
137 *		is automatically enabled for the new file descriptor.
138 *
139 *		Applying **close**\ (2) to the file descriptor returned by
140 *		**BPF_MAP_CREATE** will delete the map (but see NOTES).
141 *
142 *	Return
143 *		A new file descriptor (a nonnegative integer), or -1 if an
144 *		error occurred (in which case, *errno* is set appropriately).
145 *
146 * BPF_MAP_LOOKUP_ELEM
147 *	Description
148 *		Look up an element with a given *key* in the map referred to
149 *		by the file descriptor *map_fd*.
150 *
151 *		The *flags* argument may be specified as one of the
152 *		following:
153 *
154 *		**BPF_F_LOCK**
155 *			Look up the value of a spin-locked map without
156 *			returning the lock. This must be specified if the
157 *			elements contain a spinlock.
158 *
159 *	Return
160 *		Returns zero on success. On error, -1 is returned and *errno*
161 *		is set appropriately.
162 *
163 * BPF_MAP_UPDATE_ELEM
164 *	Description
165 *		Create or update an element (key/value pair) in a specified map.
166 *
167 *		The *flags* argument should be specified as one of the
168 *		following:
169 *
170 *		**BPF_ANY**
171 *			Create a new element or update an existing element.
172 *		**BPF_NOEXIST**
173 *			Create a new element only if it did not exist.
174 *		**BPF_EXIST**
175 *			Update an existing element.
176 *		**BPF_F_LOCK**
177 *			Update a spin_lock-ed map element.
178 *
179 *	Return
180 *		Returns zero on success. On error, -1 is returned and *errno*
181 *		is set appropriately.
182 *
183 *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
184 *		**E2BIG**, **EEXIST**, or **ENOENT**.
185 *
186 *		**E2BIG**
187 *			The number of elements in the map reached the
188 *			*max_entries* limit specified at map creation time.
189 *		**EEXIST**
190 *			If *flags* specifies **BPF_NOEXIST** and the element
191 *			with *key* already exists in the map.
192 *		**ENOENT**
193 *			If *flags* specifies **BPF_EXIST** and the element with
194 *			*key* does not exist in the map.
195 *
196 * BPF_MAP_DELETE_ELEM
197 *	Description
198 *		Look up and delete an element by key in a specified map.
199 *
200 *	Return
201 *		Returns zero on success. On error, -1 is returned and *errno*
202 *		is set appropriately.
203 *
204 * BPF_MAP_GET_NEXT_KEY
205 *	Description
206 *		Look up an element by key in a specified map and return the key
207 *		of the next element. Can be used to iterate over all elements
208 *		in the map.
209 *
210 *	Return
211 *		Returns zero on success. On error, -1 is returned and *errno*
212 *		is set appropriately.
213 *
214 *		The following cases can be used to iterate over all elements of
215 *		the map:
216 *
217 *		* If *key* is not found, the operation returns zero and sets
218 *		  the *next_key* pointer to the key of the first element.
219 *		* If *key* is found, the operation returns zero and sets the
220 *		  *next_key* pointer to the key of the next element.
221 *		* If *key* is the last element, returns -1 and *errno* is set
222 *		  to **ENOENT**.
223 *
224 *		May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
225 *		**EINVAL** on error.
226 *
227 * BPF_PROG_LOAD
228 *	Description
229 *		Verify and load an eBPF program, returning a new file
230 *		descriptor associated with the program.
231 *
232 *		Applying **close**\ (2) to the file descriptor returned by
233 *		**BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
234 *
235 *		The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
236 *		automatically enabled for the new file descriptor.
237 *
238 *	Return
239 *		A new file descriptor (a nonnegative integer), or -1 if an
240 *		error occurred (in which case, *errno* is set appropriately).
241 *
242 * BPF_OBJ_PIN
243 *	Description
244 *		Pin an eBPF program or map referred by the specified *bpf_fd*
245 *		to the provided *pathname* on the filesystem.
246 *
247 *		The *pathname* argument must not contain a dot (".").
248 *
249 *		On success, *pathname* retains a reference to the eBPF object,
250 *		preventing deallocation of the object when the original
251 *		*bpf_fd* is closed. This allow the eBPF object to live beyond
252 *		**close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
253 *		process.
254 *
255 *		Applying **unlink**\ (2) or similar calls to the *pathname*
256 *		unpins the object from the filesystem, removing the reference.
257 *		If no other file descriptors or filesystem nodes refer to the
258 *		same object, it will be deallocated (see NOTES).
259 *
260 *		The filesystem type for the parent directory of *pathname* must
261 *		be **BPF_FS_MAGIC**.
262 *
263 *	Return
264 *		Returns zero on success. On error, -1 is returned and *errno*
265 *		is set appropriately.
266 *
267 * BPF_OBJ_GET
268 *	Description
269 *		Open a file descriptor for the eBPF object pinned to the
270 *		specified *pathname*.
271 *
272 *	Return
273 *		A new file descriptor (a nonnegative integer), or -1 if an
274 *		error occurred (in which case, *errno* is set appropriately).
275 *
276 * BPF_PROG_ATTACH
277 *	Description
278 *		Attach an eBPF program to a *target_fd* at the specified
279 *		*attach_type* hook.
280 *
281 *		The *attach_type* specifies the eBPF attachment point to
282 *		attach the program to, and must be one of *bpf_attach_type*
283 *		(see below).
284 *
285 *		The *attach_bpf_fd* must be a valid file descriptor for a
286 *		loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
287 *		or sock_ops type corresponding to the specified *attach_type*.
288 *
289 *		The *target_fd* must be a valid file descriptor for a kernel
290 *		object which depends on the attach type of *attach_bpf_fd*:
291 *
292 *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
293 *		**BPF_PROG_TYPE_CGROUP_SKB**,
294 *		**BPF_PROG_TYPE_CGROUP_SOCK**,
295 *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
296 *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
297 *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
298 *		**BPF_PROG_TYPE_SOCK_OPS**
299 *
300 *			Control Group v2 hierarchy with the eBPF controller
301 *			enabled. Requires the kernel to be compiled with
302 *			**CONFIG_CGROUP_BPF**.
303 *
304 *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
305 *
306 *			Network namespace (eg /proc/self/ns/net).
307 *
308 *		**BPF_PROG_TYPE_LIRC_MODE2**
309 *
310 *			LIRC device path (eg /dev/lircN). Requires the kernel
311 *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
312 *
313 *		**BPF_PROG_TYPE_SK_SKB**,
314 *		**BPF_PROG_TYPE_SK_MSG**
315 *
316 *			eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
317 *
318 *	Return
319 *		Returns zero on success. On error, -1 is returned and *errno*
320 *		is set appropriately.
321 *
322 * BPF_PROG_DETACH
323 *	Description
324 *		Detach the eBPF program associated with the *target_fd* at the
325 *		hook specified by *attach_type*. The program must have been
326 *		previously attached using **BPF_PROG_ATTACH**.
327 *
328 *	Return
329 *		Returns zero on success. On error, -1 is returned and *errno*
330 *		is set appropriately.
331 *
332 * BPF_PROG_TEST_RUN
333 *	Description
334 *		Run the eBPF program associated with the *prog_fd* a *repeat*
335 *		number of times against a provided program context *ctx_in* and
336 *		data *data_in*, and return the modified program context
337 *		*ctx_out*, *data_out* (for example, packet data), result of the
338 *		execution *retval*, and *duration* of the test run.
339 *
340 *		The sizes of the buffers provided as input and output
341 *		parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
342 *		be provided in the corresponding variables *ctx_size_in*,
343 *		*ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
344 *		of these parameters are not provided (ie set to NULL), the
345 *		corresponding size field must be zero.
346 *
347 *		Some program types have particular requirements:
348 *
349 *		**BPF_PROG_TYPE_SK_LOOKUP**
350 *			*data_in* and *data_out* must be NULL.
351 *
352 *		**BPF_PROG_TYPE_RAW_TRACEPOINT**,
353 *		**BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
354 *
355 *			*ctx_out*, *data_in* and *data_out* must be NULL.
356 *			*repeat* must be zero.
357 *
358 *		BPF_PROG_RUN is an alias for BPF_PROG_TEST_RUN.
359 *
360 *	Return
361 *		Returns zero on success. On error, -1 is returned and *errno*
362 *		is set appropriately.
363 *
364 *		**ENOSPC**
365 *			Either *data_size_out* or *ctx_size_out* is too small.
366 *		**ENOTSUPP**
367 *			This command is not supported by the program type of
368 *			the program referred to by *prog_fd*.
369 *
370 * BPF_PROG_GET_NEXT_ID
371 *	Description
372 *		Fetch the next eBPF program currently loaded into the kernel.
373 *
374 *		Looks for the eBPF program with an id greater than *start_id*
375 *		and updates *next_id* on success. If no other eBPF programs
376 *		remain with ids higher than *start_id*, returns -1 and sets
377 *		*errno* to **ENOENT**.
378 *
379 *	Return
380 *		Returns zero on success. On error, or when no id remains, -1
381 *		is returned and *errno* is set appropriately.
382 *
383 * BPF_MAP_GET_NEXT_ID
384 *	Description
385 *		Fetch the next eBPF map currently loaded into the kernel.
386 *
387 *		Looks for the eBPF map with an id greater than *start_id*
388 *		and updates *next_id* on success. If no other eBPF maps
389 *		remain with ids higher than *start_id*, returns -1 and sets
390 *		*errno* to **ENOENT**.
391 *
392 *	Return
393 *		Returns zero on success. On error, or when no id remains, -1
394 *		is returned and *errno* is set appropriately.
395 *
396 * BPF_PROG_GET_FD_BY_ID
397 *	Description
398 *		Open a file descriptor for the eBPF program corresponding to
399 *		*prog_id*.
400 *
401 *	Return
402 *		A new file descriptor (a nonnegative integer), or -1 if an
403 *		error occurred (in which case, *errno* is set appropriately).
404 *
405 * BPF_MAP_GET_FD_BY_ID
406 *	Description
407 *		Open a file descriptor for the eBPF map corresponding to
408 *		*map_id*.
409 *
410 *	Return
411 *		A new file descriptor (a nonnegative integer), or -1 if an
412 *		error occurred (in which case, *errno* is set appropriately).
413 *
414 * BPF_OBJ_GET_INFO_BY_FD
415 *	Description
416 *		Obtain information about the eBPF object corresponding to
417 *		*bpf_fd*.
418 *
419 *		Populates up to *info_len* bytes of *info*, which will be in
420 *		one of the following formats depending on the eBPF object type
421 *		of *bpf_fd*:
422 *
423 *		* **struct bpf_prog_info**
424 *		* **struct bpf_map_info**
425 *		* **struct bpf_btf_info**
426 *		* **struct bpf_link_info**
427 *
428 *	Return
429 *		Returns zero on success. On error, -1 is returned and *errno*
430 *		is set appropriately.
431 *
432 * BPF_PROG_QUERY
433 *	Description
434 *		Obtain information about eBPF programs associated with the
435 *		specified *attach_type* hook.
436 *
437 *		The *target_fd* must be a valid file descriptor for a kernel
438 *		object which depends on the attach type of *attach_bpf_fd*:
439 *
440 *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
441 *		**BPF_PROG_TYPE_CGROUP_SKB**,
442 *		**BPF_PROG_TYPE_CGROUP_SOCK**,
443 *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
444 *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
445 *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
446 *		**BPF_PROG_TYPE_SOCK_OPS**
447 *
448 *			Control Group v2 hierarchy with the eBPF controller
449 *			enabled. Requires the kernel to be compiled with
450 *			**CONFIG_CGROUP_BPF**.
451 *
452 *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
453 *
454 *			Network namespace (eg /proc/self/ns/net).
455 *
456 *		**BPF_PROG_TYPE_LIRC_MODE2**
457 *
458 *			LIRC device path (eg /dev/lircN). Requires the kernel
459 *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
460 *
461 *		**BPF_PROG_QUERY** always fetches the number of programs
462 *		attached and the *attach_flags* which were used to attach those
463 *		programs. Additionally, if *prog_ids* is nonzero and the number
464 *		of attached programs is less than *prog_cnt*, populates
465 *		*prog_ids* with the eBPF program ids of the programs attached
466 *		at *target_fd*.
467 *
468 *		The following flags may alter the result:
469 *
470 *		**BPF_F_QUERY_EFFECTIVE**
471 *			Only return information regarding programs which are
472 *			currently effective at the specified *target_fd*.
473 *
474 *	Return
475 *		Returns zero on success. On error, -1 is returned and *errno*
476 *		is set appropriately.
477 *
478 * BPF_RAW_TRACEPOINT_OPEN
479 *	Description
480 *		Attach an eBPF program to a tracepoint *name* to access kernel
481 *		internal arguments of the tracepoint in their raw form.
482 *
483 *		The *prog_fd* must be a valid file descriptor associated with
484 *		a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
485 *
486 *		No ABI guarantees are made about the content of tracepoint
487 *		arguments exposed to the corresponding eBPF program.
488 *
489 *		Applying **close**\ (2) to the file descriptor returned by
490 *		**BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
491 *
492 *	Return
493 *		A new file descriptor (a nonnegative integer), or -1 if an
494 *		error occurred (in which case, *errno* is set appropriately).
495 *
496 * BPF_BTF_LOAD
497 *	Description
498 *		Verify and load BPF Type Format (BTF) metadata into the kernel,
499 *		returning a new file descriptor associated with the metadata.
500 *		BTF is described in more detail at
501 *		https://www.kernel.org/doc/html/latest/bpf/btf.html.
502 *
503 *		The *btf* parameter must point to valid memory providing
504 *		*btf_size* bytes of BTF binary metadata.
505 *
506 *		The returned file descriptor can be passed to other **bpf**\ ()
507 *		subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
508 *		associate the BTF with those objects.
509 *
510 *		Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
511 *		parameters to specify a *btf_log_buf*, *btf_log_size* and
512 *		*btf_log_level* which allow the kernel to return freeform log
513 *		output regarding the BTF verification process.
514 *
515 *	Return
516 *		A new file descriptor (a nonnegative integer), or -1 if an
517 *		error occurred (in which case, *errno* is set appropriately).
518 *
519 * BPF_BTF_GET_FD_BY_ID
520 *	Description
521 *		Open a file descriptor for the BPF Type Format (BTF)
522 *		corresponding to *btf_id*.
523 *
524 *	Return
525 *		A new file descriptor (a nonnegative integer), or -1 if an
526 *		error occurred (in which case, *errno* is set appropriately).
527 *
528 * BPF_TASK_FD_QUERY
529 *	Description
530 *		Obtain information about eBPF programs associated with the
531 *		target process identified by *pid* and *fd*.
532 *
533 *		If the *pid* and *fd* are associated with a tracepoint, kprobe
534 *		or uprobe perf event, then the *prog_id* and *fd_type* will
535 *		be populated with the eBPF program id and file descriptor type
536 *		of type **bpf_task_fd_type**. If associated with a kprobe or
537 *		uprobe, the  *probe_offset* and *probe_addr* will also be
538 *		populated. Optionally, if *buf* is provided, then up to
539 *		*buf_len* bytes of *buf* will be populated with the name of
540 *		the tracepoint, kprobe or uprobe.
541 *
542 *		The resulting *prog_id* may be introspected in deeper detail
543 *		using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
544 *
545 *	Return
546 *		Returns zero on success. On error, -1 is returned and *errno*
547 *		is set appropriately.
548 *
549 * BPF_MAP_LOOKUP_AND_DELETE_ELEM
550 *	Description
551 *		Look up an element with the given *key* in the map referred to
552 *		by the file descriptor *fd*, and if found, delete the element.
553 *
554 *		For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
555 *		types, the *flags* argument needs to be set to 0, but for other
556 *		map types, it may be specified as:
557 *
558 *		**BPF_F_LOCK**
559 *			Look up and delete the value of a spin-locked map
560 *			without returning the lock. This must be specified if
561 *			the elements contain a spinlock.
562 *
563 *		The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
564 *		implement this command as a "pop" operation, deleting the top
565 *		element rather than one corresponding to *key*.
566 *		The *key* and *key_len* parameters should be zeroed when
567 *		issuing this operation for these map types.
568 *
569 *		This command is only valid for the following map types:
570 *		* **BPF_MAP_TYPE_QUEUE**
571 *		* **BPF_MAP_TYPE_STACK**
572 *		* **BPF_MAP_TYPE_HASH**
573 *		* **BPF_MAP_TYPE_PERCPU_HASH**
574 *		* **BPF_MAP_TYPE_LRU_HASH**
575 *		* **BPF_MAP_TYPE_LRU_PERCPU_HASH**
576 *
577 *	Return
578 *		Returns zero on success. On error, -1 is returned and *errno*
579 *		is set appropriately.
580 *
581 * BPF_MAP_FREEZE
582 *	Description
583 *		Freeze the permissions of the specified map.
584 *
585 *		Write permissions may be frozen by passing zero *flags*.
586 *		Upon success, no future syscall invocations may alter the
587 *		map state of *map_fd*. Write operations from eBPF programs
588 *		are still possible for a frozen map.
589 *
590 *		Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
591 *
592 *	Return
593 *		Returns zero on success. On error, -1 is returned and *errno*
594 *		is set appropriately.
595 *
596 * BPF_BTF_GET_NEXT_ID
597 *	Description
598 *		Fetch the next BPF Type Format (BTF) object currently loaded
599 *		into the kernel.
600 *
601 *		Looks for the BTF object with an id greater than *start_id*
602 *		and updates *next_id* on success. If no other BTF objects
603 *		remain with ids higher than *start_id*, returns -1 and sets
604 *		*errno* to **ENOENT**.
605 *
606 *	Return
607 *		Returns zero on success. On error, or when no id remains, -1
608 *		is returned and *errno* is set appropriately.
609 *
610 * BPF_MAP_LOOKUP_BATCH
611 *	Description
612 *		Iterate and fetch multiple elements in a map.
613 *
614 *		Two opaque values are used to manage batch operations,
615 *		*in_batch* and *out_batch*. Initially, *in_batch* must be set
616 *		to NULL to begin the batched operation. After each subsequent
617 *		**BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
618 *		*out_batch* as the *in_batch* for the next operation to
619 *		continue iteration from the current point.
620 *
621 *		The *keys* and *values* are output parameters which must point
622 *		to memory large enough to hold *count* items based on the key
623 *		and value size of the map *map_fd*. The *keys* buffer must be
624 *		of *key_size* * *count*. The *values* buffer must be of
625 *		*value_size* * *count*.
626 *
627 *		The *elem_flags* argument may be specified as one of the
628 *		following:
629 *
630 *		**BPF_F_LOCK**
631 *			Look up the value of a spin-locked map without
632 *			returning the lock. This must be specified if the
633 *			elements contain a spinlock.
634 *
635 *		On success, *count* elements from the map are copied into the
636 *		user buffer, with the keys copied into *keys* and the values
637 *		copied into the corresponding indices in *values*.
638 *
639 *		If an error is returned and *errno* is not **EFAULT**, *count*
640 *		is set to the number of successfully processed elements.
641 *
642 *	Return
643 *		Returns zero on success. On error, -1 is returned and *errno*
644 *		is set appropriately.
645 *
646 *		May set *errno* to **ENOSPC** to indicate that *keys* or
647 *		*values* is too small to dump an entire bucket during
648 *		iteration of a hash-based map type.
649 *
650 * BPF_MAP_LOOKUP_AND_DELETE_BATCH
651 *	Description
652 *		Iterate and delete all elements in a map.
653 *
654 *		This operation has the same behavior as
655 *		**BPF_MAP_LOOKUP_BATCH** with two exceptions:
656 *
657 *		* Every element that is successfully returned is also deleted
658 *		  from the map. This is at least *count* elements. Note that
659 *		  *count* is both an input and an output parameter.
660 *		* Upon returning with *errno* set to **EFAULT**, up to
661 *		  *count* elements may be deleted without returning the keys
662 *		  and values of the deleted elements.
663 *
664 *	Return
665 *		Returns zero on success. On error, -1 is returned and *errno*
666 *		is set appropriately.
667 *
668 * BPF_MAP_UPDATE_BATCH
669 *	Description
670 *		Update multiple elements in a map by *key*.
671 *
672 *		The *keys* and *values* are input parameters which must point
673 *		to memory large enough to hold *count* items based on the key
674 *		and value size of the map *map_fd*. The *keys* buffer must be
675 *		of *key_size* * *count*. The *values* buffer must be of
676 *		*value_size* * *count*.
677 *
678 *		Each element specified in *keys* is sequentially updated to the
679 *		value in the corresponding index in *values*. The *in_batch*
680 *		and *out_batch* parameters are ignored and should be zeroed.
681 *
682 *		The *elem_flags* argument should be specified as one of the
683 *		following:
684 *
685 *		**BPF_ANY**
686 *			Create new elements or update a existing elements.
687 *		**BPF_NOEXIST**
688 *			Create new elements only if they do not exist.
689 *		**BPF_EXIST**
690 *			Update existing elements.
691 *		**BPF_F_LOCK**
692 *			Update spin_lock-ed map elements. This must be
693 *			specified if the map value contains a spinlock.
694 *
695 *		On success, *count* elements from the map are updated.
696 *
697 *		If an error is returned and *errno* is not **EFAULT**, *count*
698 *		is set to the number of successfully processed elements.
699 *
700 *	Return
701 *		Returns zero on success. On error, -1 is returned and *errno*
702 *		is set appropriately.
703 *
704 *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
705 *		**E2BIG**. **E2BIG** indicates that the number of elements in
706 *		the map reached the *max_entries* limit specified at map
707 *		creation time.
708 *
709 *		May set *errno* to one of the following error codes under
710 *		specific circumstances:
711 *
712 *		**EEXIST**
713 *			If *flags* specifies **BPF_NOEXIST** and the element
714 *			with *key* already exists in the map.
715 *		**ENOENT**
716 *			If *flags* specifies **BPF_EXIST** and the element with
717 *			*key* does not exist in the map.
718 *
719 * BPF_MAP_DELETE_BATCH
720 *	Description
721 *		Delete multiple elements in a map by *key*.
722 *
723 *		The *keys* parameter is an input parameter which must point
724 *		to memory large enough to hold *count* items based on the key
725 *		size of the map *map_fd*, that is, *key_size* * *count*.
726 *
727 *		Each element specified in *keys* is sequentially deleted. The
728 *		*in_batch*, *out_batch*, and *values* parameters are ignored
729 *		and should be zeroed.
730 *
731 *		The *elem_flags* argument may be specified as one of the
732 *		following:
733 *
734 *		**BPF_F_LOCK**
735 *			Look up the value of a spin-locked map without
736 *			returning the lock. This must be specified if the
737 *			elements contain a spinlock.
738 *
739 *		On success, *count* elements from the map are updated.
740 *
741 *		If an error is returned and *errno* is not **EFAULT**, *count*
742 *		is set to the number of successfully processed elements. If
743 *		*errno* is **EFAULT**, up to *count* elements may be been
744 *		deleted.
745 *
746 *	Return
747 *		Returns zero on success. On error, -1 is returned and *errno*
748 *		is set appropriately.
749 *
750 * BPF_LINK_CREATE
751 *	Description
752 *		Attach an eBPF program to a *target_fd* at the specified
753 *		*attach_type* hook and return a file descriptor handle for
754 *		managing the link.
755 *
756 *	Return
757 *		A new file descriptor (a nonnegative integer), or -1 if an
758 *		error occurred (in which case, *errno* is set appropriately).
759 *
760 * BPF_LINK_UPDATE
761 *	Description
762 *		Update the eBPF program in the specified *link_fd* to
763 *		*new_prog_fd*.
764 *
765 *	Return
766 *		Returns zero on success. On error, -1 is returned and *errno*
767 *		is set appropriately.
768 *
769 * BPF_LINK_GET_FD_BY_ID
770 *	Description
771 *		Open a file descriptor for the eBPF Link corresponding to
772 *		*link_id*.
773 *
774 *	Return
775 *		A new file descriptor (a nonnegative integer), or -1 if an
776 *		error occurred (in which case, *errno* is set appropriately).
777 *
778 * BPF_LINK_GET_NEXT_ID
779 *	Description
780 *		Fetch the next eBPF link currently loaded into the kernel.
781 *
782 *		Looks for the eBPF link with an id greater than *start_id*
783 *		and updates *next_id* on success. If no other eBPF links
784 *		remain with ids higher than *start_id*, returns -1 and sets
785 *		*errno* to **ENOENT**.
786 *
787 *	Return
788 *		Returns zero on success. On error, or when no id remains, -1
789 *		is returned and *errno* is set appropriately.
790 *
791 * BPF_ENABLE_STATS
792 *	Description
793 *		Enable eBPF runtime statistics gathering.
794 *
795 *		Runtime statistics gathering for the eBPF runtime is disabled
796 *		by default to minimize the corresponding performance overhead.
797 *		This command enables statistics globally.
798 *
799 *		Multiple programs may independently enable statistics.
800 *		After gathering the desired statistics, eBPF runtime statistics
801 *		may be disabled again by calling **close**\ (2) for the file
802 *		descriptor returned by this function. Statistics will only be
803 *		disabled system-wide when all outstanding file descriptors
804 *		returned by prior calls for this subcommand are closed.
805 *
806 *	Return
807 *		A new file descriptor (a nonnegative integer), or -1 if an
808 *		error occurred (in which case, *errno* is set appropriately).
809 *
810 * BPF_ITER_CREATE
811 *	Description
812 *		Create an iterator on top of the specified *link_fd* (as
813 *		previously created using **BPF_LINK_CREATE**) and return a
814 *		file descriptor that can be used to trigger the iteration.
815 *
816 *		If the resulting file descriptor is pinned to the filesystem
817 *		using  **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
818 *		for that path will trigger the iterator to read kernel state
819 *		using the eBPF program attached to *link_fd*.
820 *
821 *	Return
822 *		A new file descriptor (a nonnegative integer), or -1 if an
823 *		error occurred (in which case, *errno* is set appropriately).
824 *
825 * BPF_LINK_DETACH
826 *	Description
827 *		Forcefully detach the specified *link_fd* from its
828 *		corresponding attachment point.
829 *
830 *	Return
831 *		Returns zero on success. On error, -1 is returned and *errno*
832 *		is set appropriately.
833 *
834 * BPF_PROG_BIND_MAP
835 *	Description
836 *		Bind a map to the lifetime of an eBPF program.
837 *
838 *		The map identified by *map_fd* is bound to the program
839 *		identified by *prog_fd* and only released when *prog_fd* is
840 *		released. This may be used in cases where metadata should be
841 *		associated with a program which otherwise does not contain any
842 *		references to the map (for example, embedded in the eBPF
843 *		program instructions).
844 *
845 *	Return
846 *		Returns zero on success. On error, -1 is returned and *errno*
847 *		is set appropriately.
848 *
849 * NOTES
850 *	eBPF objects (maps and programs) can be shared between processes.
851 *
852 *	* After **fork**\ (2), the child inherits file descriptors
853 *	  referring to the same eBPF objects.
854 *	* File descriptors referring to eBPF objects can be transferred over
855 *	  **unix**\ (7) domain sockets.
856 *	* File descriptors referring to eBPF objects can be duplicated in the
857 *	  usual way, using **dup**\ (2) and similar calls.
858 *	* File descriptors referring to eBPF objects can be pinned to the
859 *	  filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
860 *
861 *	An eBPF object is deallocated only after all file descriptors referring
862 *	to the object have been closed and no references remain pinned to the
863 *	filesystem or attached (for example, bound to a program or device).
864 */
865enum bpf_cmd {
866	BPF_MAP_CREATE,
867	BPF_MAP_LOOKUP_ELEM,
868	BPF_MAP_UPDATE_ELEM,
869	BPF_MAP_DELETE_ELEM,
870	BPF_MAP_GET_NEXT_KEY,
871	BPF_PROG_LOAD,
872	BPF_OBJ_PIN,
873	BPF_OBJ_GET,
874	BPF_PROG_ATTACH,
875	BPF_PROG_DETACH,
876	BPF_PROG_TEST_RUN,
877	BPF_PROG_RUN = BPF_PROG_TEST_RUN,
878	BPF_PROG_GET_NEXT_ID,
879	BPF_MAP_GET_NEXT_ID,
880	BPF_PROG_GET_FD_BY_ID,
881	BPF_MAP_GET_FD_BY_ID,
882	BPF_OBJ_GET_INFO_BY_FD,
883	BPF_PROG_QUERY,
884	BPF_RAW_TRACEPOINT_OPEN,
885	BPF_BTF_LOAD,
886	BPF_BTF_GET_FD_BY_ID,
887	BPF_TASK_FD_QUERY,
888	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
889	BPF_MAP_FREEZE,
890	BPF_BTF_GET_NEXT_ID,
891	BPF_MAP_LOOKUP_BATCH,
892	BPF_MAP_LOOKUP_AND_DELETE_BATCH,
893	BPF_MAP_UPDATE_BATCH,
894	BPF_MAP_DELETE_BATCH,
895	BPF_LINK_CREATE,
896	BPF_LINK_UPDATE,
897	BPF_LINK_GET_FD_BY_ID,
898	BPF_LINK_GET_NEXT_ID,
899	BPF_ENABLE_STATS,
900	BPF_ITER_CREATE,
901	BPF_LINK_DETACH,
902	BPF_PROG_BIND_MAP,
903};
904
905enum bpf_map_type {
906	BPF_MAP_TYPE_UNSPEC,
907	BPF_MAP_TYPE_HASH,
908	BPF_MAP_TYPE_ARRAY,
909	BPF_MAP_TYPE_PROG_ARRAY,
910	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
911	BPF_MAP_TYPE_PERCPU_HASH,
912	BPF_MAP_TYPE_PERCPU_ARRAY,
913	BPF_MAP_TYPE_STACK_TRACE,
914	BPF_MAP_TYPE_CGROUP_ARRAY,
915	BPF_MAP_TYPE_LRU_HASH,
916	BPF_MAP_TYPE_LRU_PERCPU_HASH,
917	BPF_MAP_TYPE_LPM_TRIE,
918	BPF_MAP_TYPE_ARRAY_OF_MAPS,
919	BPF_MAP_TYPE_HASH_OF_MAPS,
920	BPF_MAP_TYPE_DEVMAP,
921	BPF_MAP_TYPE_SOCKMAP,
922	BPF_MAP_TYPE_CPUMAP,
923	BPF_MAP_TYPE_XSKMAP,
924	BPF_MAP_TYPE_SOCKHASH,
925	BPF_MAP_TYPE_CGROUP_STORAGE,
926	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
927	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
928	BPF_MAP_TYPE_QUEUE,
929	BPF_MAP_TYPE_STACK,
930	BPF_MAP_TYPE_SK_STORAGE,
931	BPF_MAP_TYPE_DEVMAP_HASH,
932	BPF_MAP_TYPE_STRUCT_OPS,
933	BPF_MAP_TYPE_RINGBUF,
934	BPF_MAP_TYPE_INODE_STORAGE,
935	BPF_MAP_TYPE_TASK_STORAGE,
936	BPF_MAP_TYPE_BLOOM_FILTER,
937	BPF_MAP_TYPE_USER_RINGBUF,
938};
939
940/* Note that tracing related programs such as
941 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
942 * are not subject to a stable API since kernel internal data
943 * structures can change from release to release and may
944 * therefore break existing tracing BPF programs. Tracing BPF
945 * programs correspond to /a/ specific kernel which is to be
946 * analyzed, and not /a/ specific kernel /and/ all future ones.
947 */
948enum bpf_prog_type {
949	BPF_PROG_TYPE_UNSPEC,
950	BPF_PROG_TYPE_SOCKET_FILTER,
951	BPF_PROG_TYPE_KPROBE,
952	BPF_PROG_TYPE_SCHED_CLS,
953	BPF_PROG_TYPE_SCHED_ACT,
954	BPF_PROG_TYPE_TRACEPOINT,
955	BPF_PROG_TYPE_XDP,
956	BPF_PROG_TYPE_PERF_EVENT,
957	BPF_PROG_TYPE_CGROUP_SKB,
958	BPF_PROG_TYPE_CGROUP_SOCK,
959	BPF_PROG_TYPE_LWT_IN,
960	BPF_PROG_TYPE_LWT_OUT,
961	BPF_PROG_TYPE_LWT_XMIT,
962	BPF_PROG_TYPE_SOCK_OPS,
963	BPF_PROG_TYPE_SK_SKB,
964	BPF_PROG_TYPE_CGROUP_DEVICE,
965	BPF_PROG_TYPE_SK_MSG,
966	BPF_PROG_TYPE_RAW_TRACEPOINT,
967	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
968	BPF_PROG_TYPE_LWT_SEG6LOCAL,
969	BPF_PROG_TYPE_LIRC_MODE2,
970	BPF_PROG_TYPE_SK_REUSEPORT,
971	BPF_PROG_TYPE_FLOW_DISSECTOR,
972	BPF_PROG_TYPE_CGROUP_SYSCTL,
973	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
974	BPF_PROG_TYPE_CGROUP_SOCKOPT,
975	BPF_PROG_TYPE_TRACING,
976	BPF_PROG_TYPE_STRUCT_OPS,
977	BPF_PROG_TYPE_EXT,
978	BPF_PROG_TYPE_LSM,
979	BPF_PROG_TYPE_SK_LOOKUP,
980	BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
981};
982
983enum bpf_attach_type {
984	BPF_CGROUP_INET_INGRESS,
985	BPF_CGROUP_INET_EGRESS,
986	BPF_CGROUP_INET_SOCK_CREATE,
987	BPF_CGROUP_SOCK_OPS,
988	BPF_SK_SKB_STREAM_PARSER,
989	BPF_SK_SKB_STREAM_VERDICT,
990	BPF_CGROUP_DEVICE,
991	BPF_SK_MSG_VERDICT,
992	BPF_CGROUP_INET4_BIND,
993	BPF_CGROUP_INET6_BIND,
994	BPF_CGROUP_INET4_CONNECT,
995	BPF_CGROUP_INET6_CONNECT,
996	BPF_CGROUP_INET4_POST_BIND,
997	BPF_CGROUP_INET6_POST_BIND,
998	BPF_CGROUP_UDP4_SENDMSG,
999	BPF_CGROUP_UDP6_SENDMSG,
1000	BPF_LIRC_MODE2,
1001	BPF_FLOW_DISSECTOR,
1002	BPF_CGROUP_SYSCTL,
1003	BPF_CGROUP_UDP4_RECVMSG,
1004	BPF_CGROUP_UDP6_RECVMSG,
1005	BPF_CGROUP_GETSOCKOPT,
1006	BPF_CGROUP_SETSOCKOPT,
1007	BPF_TRACE_RAW_TP,
1008	BPF_TRACE_FENTRY,
1009	BPF_TRACE_FEXIT,
1010	BPF_MODIFY_RETURN,
1011	BPF_LSM_MAC,
1012	BPF_TRACE_ITER,
1013	BPF_CGROUP_INET4_GETPEERNAME,
1014	BPF_CGROUP_INET6_GETPEERNAME,
1015	BPF_CGROUP_INET4_GETSOCKNAME,
1016	BPF_CGROUP_INET6_GETSOCKNAME,
1017	BPF_XDP_DEVMAP,
1018	BPF_CGROUP_INET_SOCK_RELEASE,
1019	BPF_XDP_CPUMAP,
1020	BPF_SK_LOOKUP,
1021	BPF_XDP,
1022	BPF_SK_SKB_VERDICT,
1023	BPF_SK_REUSEPORT_SELECT,
1024	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
1025	BPF_PERF_EVENT,
1026	BPF_TRACE_KPROBE_MULTI,
1027	BPF_LSM_CGROUP,
1028	__MAX_BPF_ATTACH_TYPE
1029};
1030
1031#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1032
1033enum bpf_link_type {
1034	BPF_LINK_TYPE_UNSPEC = 0,
1035	BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
1036	BPF_LINK_TYPE_TRACING = 2,
1037	BPF_LINK_TYPE_CGROUP = 3,
1038	BPF_LINK_TYPE_ITER = 4,
1039	BPF_LINK_TYPE_NETNS = 5,
1040	BPF_LINK_TYPE_XDP = 6,
1041	BPF_LINK_TYPE_PERF_EVENT = 7,
1042	BPF_LINK_TYPE_KPROBE_MULTI = 8,
1043	BPF_LINK_TYPE_STRUCT_OPS = 9,
1044
1045	MAX_BPF_LINK_TYPE,
1046};
1047
1048/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
1049 *
1050 * NONE(default): No further bpf programs allowed in the subtree.
1051 *
1052 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1053 * the program in this cgroup yields to sub-cgroup program.
1054 *
1055 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1056 * that cgroup program gets run in addition to the program in this cgroup.
1057 *
1058 * Only one program is allowed to be attached to a cgroup with
1059 * NONE or BPF_F_ALLOW_OVERRIDE flag.
1060 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1061 * release old program and attach the new one. Attach flags has to match.
1062 *
1063 * Multiple programs are allowed to be attached to a cgroup with
1064 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1065 * (those that were attached first, run first)
1066 * The programs of sub-cgroup are executed first, then programs of
1067 * this cgroup and then programs of parent cgroup.
1068 * When children program makes decision (like picking TCP CA or sock bind)
1069 * parent program has a chance to override it.
1070 *
1071 * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1072 * programs for a cgroup. Though it's possible to replace an old program at
1073 * any position by also specifying BPF_F_REPLACE flag and position itself in
1074 * replace_bpf_fd attribute. Old program at this position will be released.
1075 *
1076 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1077 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
1078 * Ex1:
1079 * cgrp1 (MULTI progs A, B) ->
1080 *    cgrp2 (OVERRIDE prog C) ->
1081 *      cgrp3 (MULTI prog D) ->
1082 *        cgrp4 (OVERRIDE prog E) ->
1083 *          cgrp5 (NONE prog F)
1084 * the event in cgrp5 triggers execution of F,D,A,B in that order.
1085 * if prog F is detached, the execution is E,D,A,B
1086 * if prog F and D are detached, the execution is E,A,B
1087 * if prog F, E and D are detached, the execution is C,A,B
1088 *
1089 * All eligible programs are executed regardless of return code from
1090 * earlier programs.
1091 */
1092#define BPF_F_ALLOW_OVERRIDE	(1U << 0)
1093#define BPF_F_ALLOW_MULTI	(1U << 1)
1094#define BPF_F_REPLACE		(1U << 2)
1095
1096/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
1097 * verifier will perform strict alignment checking as if the kernel
1098 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1099 * and NET_IP_ALIGN defined to 2.
1100 */
1101#define BPF_F_STRICT_ALIGNMENT	(1U << 0)
1102
1103/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
1104 * verifier will allow any alignment whatsoever.  On platforms
1105 * with strict alignment requirements for loads ands stores (such
1106 * as sparc and mips) the verifier validates that all loads and
1107 * stores provably follow this requirement.  This flag turns that
1108 * checking and enforcement off.
1109 *
1110 * It is mostly used for testing when we want to validate the
1111 * context and memory access aspects of the verifier, but because
1112 * of an unaligned access the alignment check would trigger before
1113 * the one we are interested in.
1114 */
1115#define BPF_F_ANY_ALIGNMENT	(1U << 1)
1116
1117/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
1118 * Verifier does sub-register def/use analysis and identifies instructions whose
1119 * def only matters for low 32-bit, high 32-bit is never referenced later
1120 * through implicit zero extension. Therefore verifier notifies JIT back-ends
1121 * that it is safe to ignore clearing high 32-bit for these instructions. This
1122 * saves some back-ends a lot of code-gen. However such optimization is not
1123 * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1124 * hence hasn't used verifier's analysis result. But, we really want to have a
1125 * way to be able to verify the correctness of the described optimization on
1126 * x86_64 on which testsuites are frequently exercised.
1127 *
1128 * So, this flag is introduced. Once it is set, verifier will randomize high
1129 * 32-bit for those instructions who has been identified as safe to ignore them.
1130 * Then, if verifier is not doing correct analysis, such randomization will
1131 * regress tests to expose bugs.
1132 */
1133#define BPF_F_TEST_RND_HI32	(1U << 2)
1134
1135/* The verifier internal test flag. Behavior is undefined */
1136#define BPF_F_TEST_STATE_FREQ	(1U << 3)
1137
1138/* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
1139 * restrict map and helper usage for such programs. Sleepable BPF programs can
1140 * only be attached to hooks where kernel execution context allows sleeping.
1141 * Such programs are allowed to use helpers that may sleep like
1142 * bpf_copy_from_user().
1143 */
1144#define BPF_F_SLEEPABLE		(1U << 4)
1145
1146/* If BPF_F_XDP_HAS_FRAGS is used in BPF_PROG_LOAD command, the loaded program
1147 * fully support xdp frags.
1148 */
1149#define BPF_F_XDP_HAS_FRAGS	(1U << 5)
1150
1151/* link_create.kprobe_multi.flags used in LINK_CREATE command for
1152 * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
1153 */
1154#define BPF_F_KPROBE_MULTI_RETURN	(1U << 0)
1155
1156/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
1157 * the following extensions:
1158 *
1159 * insn[0].src_reg:  BPF_PSEUDO_MAP_[FD|IDX]
1160 * insn[0].imm:      map fd or fd_idx
1161 * insn[1].imm:      0
1162 * insn[0].off:      0
1163 * insn[1].off:      0
1164 * ldimm64 rewrite:  address of map
1165 * verifier type:    CONST_PTR_TO_MAP
1166 */
1167#define BPF_PSEUDO_MAP_FD	1
1168#define BPF_PSEUDO_MAP_IDX	5
1169
1170/* insn[0].src_reg:  BPF_PSEUDO_MAP_[IDX_]VALUE
1171 * insn[0].imm:      map fd or fd_idx
1172 * insn[1].imm:      offset into value
1173 * insn[0].off:      0
1174 * insn[1].off:      0
1175 * ldimm64 rewrite:  address of map[0]+offset
1176 * verifier type:    PTR_TO_MAP_VALUE
1177 */
1178#define BPF_PSEUDO_MAP_VALUE		2
1179#define BPF_PSEUDO_MAP_IDX_VALUE	6
1180
1181/* insn[0].src_reg:  BPF_PSEUDO_BTF_ID
1182 * insn[0].imm:      kernel btd id of VAR
1183 * insn[1].imm:      0
1184 * insn[0].off:      0
1185 * insn[1].off:      0
1186 * ldimm64 rewrite:  address of the kernel variable
1187 * verifier type:    PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1188 *                   is struct/union.
1189 */
1190#define BPF_PSEUDO_BTF_ID	3
1191/* insn[0].src_reg:  BPF_PSEUDO_FUNC
1192 * insn[0].imm:      insn offset to the func
1193 * insn[1].imm:      0
1194 * insn[0].off:      0
1195 * insn[1].off:      0
1196 * ldimm64 rewrite:  address of the function
1197 * verifier type:    PTR_TO_FUNC.
1198 */
1199#define BPF_PSEUDO_FUNC		4
1200
1201/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
1202 * offset to another bpf function
1203 */
1204#define BPF_PSEUDO_CALL		1
1205/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
1206 * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1207 */
1208#define BPF_PSEUDO_KFUNC_CALL	2
1209
1210/* flags for BPF_MAP_UPDATE_ELEM command */
1211enum {
1212	BPF_ANY		= 0, /* create new element or update existing */
1213	BPF_NOEXIST	= 1, /* create new element if it didn't exist */
1214	BPF_EXIST	= 2, /* update existing element */
1215	BPF_F_LOCK	= 4, /* spin_lock-ed map_lookup/map_update */
1216};
1217
1218/* flags for BPF_MAP_CREATE command */
1219enum {
1220	BPF_F_NO_PREALLOC	= (1U << 0),
1221/* Instead of having one common LRU list in the
1222 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1223 * which can scale and perform better.
1224 * Note, the LRU nodes (including free nodes) cannot be moved
1225 * across different LRU lists.
1226 */
1227	BPF_F_NO_COMMON_LRU	= (1U << 1),
1228/* Specify numa node during map creation */
1229	BPF_F_NUMA_NODE		= (1U << 2),
1230
1231/* Flags for accessing BPF object from syscall side. */
1232	BPF_F_RDONLY		= (1U << 3),
1233	BPF_F_WRONLY		= (1U << 4),
1234
1235/* Flag for stack_map, store build_id+offset instead of pointer */
1236	BPF_F_STACK_BUILD_ID	= (1U << 5),
1237
1238/* Zero-initialize hash function seed. This should only be used for testing. */
1239	BPF_F_ZERO_SEED		= (1U << 6),
1240
1241/* Flags for accessing BPF object from program side. */
1242	BPF_F_RDONLY_PROG	= (1U << 7),
1243	BPF_F_WRONLY_PROG	= (1U << 8),
1244
1245/* Clone map from listener for newly accepted socket */
1246	BPF_F_CLONE		= (1U << 9),
1247
1248/* Enable memory-mapping BPF map */
1249	BPF_F_MMAPABLE		= (1U << 10),
1250
1251/* Share perf_event among processes */
1252	BPF_F_PRESERVE_ELEMS	= (1U << 11),
1253
1254/* Create a map that is suitable to be an inner map with dynamic max entries */
1255	BPF_F_INNER_MAP		= (1U << 12),
1256};
1257
1258/* Flags for BPF_PROG_QUERY. */
1259
1260/* Query effective (directly attached + inherited from ancestor cgroups)
1261 * programs that will be executed for events within a cgroup.
1262 * attach_flags with this flag are always returned 0.
1263 */
1264#define BPF_F_QUERY_EFFECTIVE	(1U << 0)
1265
1266/* Flags for BPF_PROG_TEST_RUN */
1267
1268/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
1269#define BPF_F_TEST_RUN_ON_CPU	(1U << 0)
1270/* If set, XDP frames will be transmitted after processing */
1271#define BPF_F_TEST_XDP_LIVE_FRAMES	(1U << 1)
1272
1273/* type for BPF_ENABLE_STATS */
1274enum bpf_stats_type {
1275	/* enabled run_time_ns and run_cnt */
1276	BPF_STATS_RUN_TIME = 0,
1277};
1278
1279enum bpf_stack_build_id_status {
1280	/* user space need an empty entry to identify end of a trace */
1281	BPF_STACK_BUILD_ID_EMPTY = 0,
1282	/* with valid build_id and offset */
1283	BPF_STACK_BUILD_ID_VALID = 1,
1284	/* couldn't get build_id, fallback to ip */
1285	BPF_STACK_BUILD_ID_IP = 2,
1286};
1287
1288#define BPF_BUILD_ID_SIZE 20
1289struct bpf_stack_build_id {
1290	__s32		status;
1291	unsigned char	build_id[BPF_BUILD_ID_SIZE];
1292	union {
1293		__u64	offset;
1294		__u64	ip;
1295	};
1296};
1297
1298#define BPF_OBJ_NAME_LEN 16U
1299
1300union bpf_attr {
1301	struct { /* anonymous struct used by BPF_MAP_CREATE command */
1302		__u32	map_type;	/* one of enum bpf_map_type */
1303		__u32	key_size;	/* size of key in bytes */
1304		__u32	value_size;	/* size of value in bytes */
1305		__u32	max_entries;	/* max number of entries in a map */
1306		__u32	map_flags;	/* BPF_MAP_CREATE related
1307					 * flags defined above.
1308					 */
1309		__u32	inner_map_fd;	/* fd pointing to the inner map */
1310		__u32	numa_node;	/* numa node (effective only if
1311					 * BPF_F_NUMA_NODE is set).
1312					 */
1313		char	map_name[BPF_OBJ_NAME_LEN];
1314		__u32	map_ifindex;	/* ifindex of netdev to create on */
1315		__u32	btf_fd;		/* fd pointing to a BTF type data */
1316		__u32	btf_key_type_id;	/* BTF type_id of the key */
1317		__u32	btf_value_type_id;	/* BTF type_id of the value */
1318		__u32	btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
1319						   * struct stored as the
1320						   * map value
1321						   */
1322		/* Any per-map-type extra fields
1323		 *
1324		 * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
1325		 * number of hash functions (if 0, the bloom filter will default
1326		 * to using 5 hash functions).
1327		 */
1328		__u64	map_extra;
1329	};
1330
1331	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
1332		__u32		map_fd;
1333		__aligned_u64	key;
1334		union {
1335			__aligned_u64 value;
1336			__aligned_u64 next_key;
1337		};
1338		__u64		flags;
1339	};
1340
1341	struct { /* struct used by BPF_MAP_*_BATCH commands */
1342		__aligned_u64	in_batch;	/* start batch,
1343						 * NULL to start from beginning
1344						 */
1345		__aligned_u64	out_batch;	/* output: next start batch */
1346		__aligned_u64	keys;
1347		__aligned_u64	values;
1348		__u32		count;		/* input/output:
1349						 * input: # of key/value
1350						 * elements
1351						 * output: # of filled elements
1352						 */
1353		__u32		map_fd;
1354		__u64		elem_flags;
1355		__u64		flags;
1356	} batch;
1357
1358	struct { /* anonymous struct used by BPF_PROG_LOAD command */
1359		__u32		prog_type;	/* one of enum bpf_prog_type */
1360		__u32		insn_cnt;
1361		__aligned_u64	insns;
1362		__aligned_u64	license;
1363		__u32		log_level;	/* verbosity level of verifier */
1364		__u32		log_size;	/* size of user buffer */
1365		__aligned_u64	log_buf;	/* user supplied buffer */
1366		__u32		kern_version;	/* not used */
1367		__u32		prog_flags;
1368		char		prog_name[BPF_OBJ_NAME_LEN];
1369		__u32		prog_ifindex;	/* ifindex of netdev to prep for */
1370		/* For some prog types expected attach type must be known at
1371		 * load time to verify attach type specific parts of prog
1372		 * (context accesses, allowed helpers, etc).
1373		 */
1374		__u32		expected_attach_type;
1375		__u32		prog_btf_fd;	/* fd pointing to BTF type data */
1376		__u32		func_info_rec_size;	/* userspace bpf_func_info size */
1377		__aligned_u64	func_info;	/* func info */
1378		__u32		func_info_cnt;	/* number of bpf_func_info records */
1379		__u32		line_info_rec_size;	/* userspace bpf_line_info size */
1380		__aligned_u64	line_info;	/* line info */
1381		__u32		line_info_cnt;	/* number of bpf_line_info records */
1382		__u32		attach_btf_id;	/* in-kernel BTF type id to attach to */
1383		union {
1384			/* valid prog_fd to attach to bpf prog */
1385			__u32		attach_prog_fd;
1386			/* or valid module BTF object fd or 0 to attach to vmlinux */
1387			__u32		attach_btf_obj_fd;
1388		};
1389		__u32		core_relo_cnt;	/* number of bpf_core_relo */
1390		__aligned_u64	fd_array;	/* array of FDs */
1391		__aligned_u64	core_relos;
1392		__u32		core_relo_rec_size; /* sizeof(struct bpf_core_relo) */
1393	};
1394
1395	struct { /* anonymous struct used by BPF_OBJ_* commands */
1396		__aligned_u64	pathname;
1397		__u32		bpf_fd;
1398		__u32		file_flags;
1399	};
1400
1401	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
1402		__u32		target_fd;	/* container object to attach to */
1403		__u32		attach_bpf_fd;	/* eBPF program to attach */
1404		__u32		attach_type;
1405		__u32		attach_flags;
1406		__u32		replace_bpf_fd;	/* previously attached eBPF
1407						 * program to replace if
1408						 * BPF_F_REPLACE is used
1409						 */
1410	};
1411
1412	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
1413		__u32		prog_fd;
1414		__u32		retval;
1415		__u32		data_size_in;	/* input: len of data_in */
1416		__u32		data_size_out;	/* input/output: len of data_out
1417						 *   returns ENOSPC if data_out
1418						 *   is too small.
1419						 */
1420		__aligned_u64	data_in;
1421		__aligned_u64	data_out;
1422		__u32		repeat;
1423		__u32		duration;
1424		__u32		ctx_size_in;	/* input: len of ctx_in */
1425		__u32		ctx_size_out;	/* input/output: len of ctx_out
1426						 *   returns ENOSPC if ctx_out
1427						 *   is too small.
1428						 */
1429		__aligned_u64	ctx_in;
1430		__aligned_u64	ctx_out;
1431		__u32		flags;
1432		__u32		cpu;
1433		__u32		batch_size;
1434	} test;
1435
1436	struct { /* anonymous struct used by BPF_*_GET_*_ID */
1437		union {
1438			__u32		start_id;
1439			__u32		prog_id;
1440			__u32		map_id;
1441			__u32		btf_id;
1442			__u32		link_id;
1443		};
1444		__u32		next_id;
1445		__u32		open_flags;
1446	};
1447
1448	struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
1449		__u32		bpf_fd;
1450		__u32		info_len;
1451		__aligned_u64	info;
1452	} info;
1453
1454	struct { /* anonymous struct used by BPF_PROG_QUERY command */
1455		__u32		target_fd;	/* container object to query */
1456		__u32		attach_type;
1457		__u32		query_flags;
1458		__u32		attach_flags;
1459		__aligned_u64	prog_ids;
1460		__u32		prog_cnt;
1461		/* output: per-program attach_flags.
1462		 * not allowed to be set during effective query.
1463		 */
1464		__aligned_u64	prog_attach_flags;
1465	} query;
1466
1467	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
1468		__u64 name;
1469		__u32 prog_fd;
1470	} raw_tracepoint;
1471
1472	struct { /* anonymous struct for BPF_BTF_LOAD */
1473		__aligned_u64	btf;
1474		__aligned_u64	btf_log_buf;
1475		__u32		btf_size;
1476		__u32		btf_log_size;
1477		__u32		btf_log_level;
1478	};
1479
1480	struct {
1481		__u32		pid;		/* input: pid */
1482		__u32		fd;		/* input: fd */
1483		__u32		flags;		/* input: flags */
1484		__u32		buf_len;	/* input/output: buf len */
1485		__aligned_u64	buf;		/* input/output:
1486						 *   tp_name for tracepoint
1487						 *   symbol for kprobe
1488						 *   filename for uprobe
1489						 */
1490		__u32		prog_id;	/* output: prod_id */
1491		__u32		fd_type;	/* output: BPF_FD_TYPE_* */
1492		__u64		probe_offset;	/* output: probe_offset */
1493		__u64		probe_addr;	/* output: probe_addr */
1494	} task_fd_query;
1495
1496	struct { /* struct used by BPF_LINK_CREATE command */
1497		__u32		prog_fd;	/* eBPF program to attach */
1498		union {
1499			__u32		target_fd;	/* object to attach to */
1500			__u32		target_ifindex; /* target ifindex */
1501		};
1502		__u32		attach_type;	/* attach type */
1503		__u32		flags;		/* extra flags */
1504		union {
1505			__u32		target_btf_id;	/* btf_id of target to attach to */
1506			struct {
1507				__aligned_u64	iter_info;	/* extra bpf_iter_link_info */
1508				__u32		iter_info_len;	/* iter_info length */
1509			};
1510			struct {
1511				/* black box user-provided value passed through
1512				 * to BPF program at the execution time and
1513				 * accessible through bpf_get_attach_cookie() BPF helper
1514				 */
1515				__u64		bpf_cookie;
1516			} perf_event;
1517			struct {
1518				__u32		flags;
1519				__u32		cnt;
1520				__aligned_u64	syms;
1521				__aligned_u64	addrs;
1522				__aligned_u64	cookies;
1523			} kprobe_multi;
1524			struct {
1525				/* this is overlaid with the target_btf_id above. */
1526				__u32		target_btf_id;
1527				/* black box user-provided value passed through
1528				 * to BPF program at the execution time and
1529				 * accessible through bpf_get_attach_cookie() BPF helper
1530				 */
1531				__u64		cookie;
1532			} tracing;
1533		};
1534	} link_create;
1535
1536	struct { /* struct used by BPF_LINK_UPDATE command */
1537		__u32		link_fd;	/* link fd */
1538		/* new program fd to update link with */
1539		__u32		new_prog_fd;
1540		__u32		flags;		/* extra flags */
1541		/* expected link's program fd; is specified only if
1542		 * BPF_F_REPLACE flag is set in flags */
1543		__u32		old_prog_fd;
1544	} link_update;
1545
1546	struct {
1547		__u32		link_fd;
1548	} link_detach;
1549
1550	struct { /* struct used by BPF_ENABLE_STATS command */
1551		__u32		type;
1552	} enable_stats;
1553
1554	struct { /* struct used by BPF_ITER_CREATE command */
1555		__u32		link_fd;
1556		__u32		flags;
1557	} iter_create;
1558
1559	struct { /* struct used by BPF_PROG_BIND_MAP command */
1560		__u32		prog_fd;
1561		__u32		map_fd;
1562		__u32		flags;		/* extra flags */
1563	} prog_bind_map;
1564
1565} __attribute__((aligned(8)));
1566
1567/* The description below is an attempt at providing documentation to eBPF
1568 * developers about the multiple available eBPF helper functions. It can be
1569 * parsed and used to produce a manual page. The workflow is the following,
1570 * and requires the rst2man utility:
1571 *
1572 *     $ ./scripts/bpf_doc.py \
1573 *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1574 *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1575 *     $ man /tmp/bpf-helpers.7
1576 *
1577 * Note that in order to produce this external documentation, some RST
1578 * formatting is used in the descriptions to get "bold" and "italics" in
1579 * manual pages. Also note that the few trailing white spaces are
1580 * intentional, removing them would break paragraphs for rst2man.
1581 *
1582 * Start of BPF helper function descriptions:
1583 *
1584 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
1585 * 	Description
1586 * 		Perform a lookup in *map* for an entry associated to *key*.
1587 * 	Return
1588 * 		Map value associated to *key*, or **NULL** if no entry was
1589 * 		found.
1590 *
1591 * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
1592 * 	Description
1593 * 		Add or update the value of the entry associated to *key* in
1594 * 		*map* with *value*. *flags* is one of:
1595 *
1596 * 		**BPF_NOEXIST**
1597 * 			The entry for *key* must not exist in the map.
1598 * 		**BPF_EXIST**
1599 * 			The entry for *key* must already exist in the map.
1600 * 		**BPF_ANY**
1601 * 			No condition on the existence of the entry for *key*.
1602 *
1603 * 		Flag value **BPF_NOEXIST** cannot be used for maps of types
1604 * 		**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
1605 * 		elements always exist), the helper would return an error.
1606 * 	Return
1607 * 		0 on success, or a negative error in case of failure.
1608 *
1609 * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
1610 * 	Description
1611 * 		Delete entry with *key* from *map*.
1612 * 	Return
1613 * 		0 on success, or a negative error in case of failure.
1614 *
1615 * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
1616 * 	Description
1617 * 		For tracing programs, safely attempt to read *size* bytes from
1618 * 		kernel space address *unsafe_ptr* and store the data in *dst*.
1619 *
1620 * 		Generally, use **bpf_probe_read_user**\ () or
1621 * 		**bpf_probe_read_kernel**\ () instead.
1622 * 	Return
1623 * 		0 on success, or a negative error in case of failure.
1624 *
1625 * u64 bpf_ktime_get_ns(void)
1626 * 	Description
1627 * 		Return the time elapsed since system boot, in nanoseconds.
1628 * 		Does not include time the system was suspended.
1629 * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
1630 * 	Return
1631 * 		Current *ktime*.
1632 *
1633 * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1634 * 	Description
1635 * 		This helper is a "printk()-like" facility for debugging. It
1636 * 		prints a message defined by format *fmt* (of size *fmt_size*)
1637 * 		to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
1638 * 		available. It can take up to three additional **u64**
1639 * 		arguments (as an eBPF helpers, the total number of arguments is
1640 * 		limited to five).
1641 *
1642 * 		Each time the helper is called, it appends a line to the trace.
1643 * 		Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
1644 * 		open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
1645 * 		The format of the trace is customizable, and the exact output
1646 * 		one will get depends on the options set in
1647 * 		*\/sys/kernel/debug/tracing/trace_options* (see also the
1648 * 		*README* file under the same directory). However, it usually
1649 * 		defaults to something like:
1650 *
1651 * 		::
1652 *
1653 * 			telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1654 *
1655 * 		In the above:
1656 *
1657 * 			* ``telnet`` is the name of the current task.
1658 * 			* ``470`` is the PID of the current task.
1659 * 			* ``001`` is the CPU number on which the task is
1660 * 			  running.
1661 * 			* In ``.N..``, each character refers to a set of
1662 * 			  options (whether irqs are enabled, scheduling
1663 * 			  options, whether hard/softirqs are running, level of
1664 * 			  preempt_disabled respectively). **N** means that
1665 * 			  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
1666 * 			  are set.
1667 * 			* ``419421.045894`` is a timestamp.
1668 * 			* ``0x00000001`` is a fake value used by BPF for the
1669 * 			  instruction pointer register.
1670 * 			* ``<formatted msg>`` is the message formatted with
1671 * 			  *fmt*.
1672 *
1673 * 		The conversion specifiers supported by *fmt* are similar, but
1674 * 		more limited than for printk(). They are **%d**, **%i**,
1675 * 		**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
1676 * 		**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
1677 * 		of field, padding with zeroes, etc.) is available, and the
1678 * 		helper will return **-EINVAL** (but print nothing) if it
1679 * 		encounters an unknown specifier.
1680 *
1681 * 		Also, note that **bpf_trace_printk**\ () is slow, and should
1682 * 		only be used for debugging purposes. For this reason, a notice
1683 * 		block (spanning several lines) is printed to kernel logs and
1684 * 		states that the helper should not be used "for production use"
1685 * 		the first time this helper is used (or more precisely, when
1686 * 		**trace_printk**\ () buffers are allocated). For passing values
1687 * 		to user space, perf events should be preferred.
1688 * 	Return
1689 * 		The number of bytes written to the buffer, or a negative error
1690 * 		in case of failure.
1691 *
1692 * u32 bpf_get_prandom_u32(void)
1693 * 	Description
1694 * 		Get a pseudo-random number.
1695 *
1696 * 		From a security point of view, this helper uses its own
1697 * 		pseudo-random internal state, and cannot be used to infer the
1698 * 		seed of other random functions in the kernel. However, it is
1699 * 		essential to note that the generator used by the helper is not
1700 * 		cryptographically secure.
1701 * 	Return
1702 * 		A random 32-bit unsigned value.
1703 *
1704 * u32 bpf_get_smp_processor_id(void)
1705 * 	Description
1706 * 		Get the SMP (symmetric multiprocessing) processor id. Note that
1707 * 		all programs run with migration disabled, which means that the
1708 * 		SMP processor id is stable during all the execution of the
1709 * 		program.
1710 * 	Return
1711 * 		The SMP id of the processor running the program.
1712 *
1713 * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
1714 * 	Description
1715 * 		Store *len* bytes from address *from* into the packet
1716 * 		associated to *skb*, at *offset*. *flags* are a combination of
1717 * 		**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
1718 * 		checksum for the packet after storing the bytes) and
1719 * 		**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
1720 * 		**->swhash** and *skb*\ **->l4hash** to 0).
1721 *
1722 * 		A call to this helper is susceptible to change the underlying
1723 * 		packet buffer. Therefore, at load time, all checks on pointers
1724 * 		previously done by the verifier are invalidated and must be
1725 * 		performed again, if the helper is used in combination with
1726 * 		direct packet access.
1727 * 	Return
1728 * 		0 on success, or a negative error in case of failure.
1729 *
1730 * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1731 * 	Description
1732 * 		Recompute the layer 3 (e.g. IP) checksum for the packet
1733 * 		associated to *skb*. Computation is incremental, so the helper
1734 * 		must know the former value of the header field that was
1735 * 		modified (*from*), the new value of this field (*to*), and the
1736 * 		number of bytes (2 or 4) for this field, stored in *size*.
1737 * 		Alternatively, it is possible to store the difference between
1738 * 		the previous and the new values of the header field in *to*, by
1739 * 		setting *from* and *size* to 0. For both methods, *offset*
1740 * 		indicates the location of the IP checksum within the packet.
1741 *
1742 * 		This helper works in combination with **bpf_csum_diff**\ (),
1743 * 		which does not update the checksum in-place, but offers more
1744 * 		flexibility and can handle sizes larger than 2 or 4 for the
1745 * 		checksum to update.
1746 *
1747 * 		A call to this helper is susceptible to change the underlying
1748 * 		packet buffer. Therefore, at load time, all checks on pointers
1749 * 		previously done by the verifier are invalidated and must be
1750 * 		performed again, if the helper is used in combination with
1751 * 		direct packet access.
1752 * 	Return
1753 * 		0 on success, or a negative error in case of failure.
1754 *
1755 * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1756 * 	Description
1757 * 		Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1758 * 		packet associated to *skb*. Computation is incremental, so the
1759 * 		helper must know the former value of the header field that was
1760 * 		modified (*from*), the new value of this field (*to*), and the
1761 * 		number of bytes (2 or 4) for this field, stored on the lowest
1762 * 		four bits of *flags*. Alternatively, it is possible to store
1763 * 		the difference between the previous and the new values of the
1764 * 		header field in *to*, by setting *from* and the four lowest
1765 * 		bits of *flags* to 0. For both methods, *offset* indicates the
1766 * 		location of the IP checksum within the packet. In addition to
1767 * 		the size of the field, *flags* can be added (bitwise OR) actual
1768 * 		flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
1769 * 		untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
1770 * 		for updates resulting in a null checksum the value is set to
1771 * 		**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
1772 * 		the checksum is to be computed against a pseudo-header.
1773 *
1774 * 		This helper works in combination with **bpf_csum_diff**\ (),
1775 * 		which does not update the checksum in-place, but offers more
1776 * 		flexibility and can handle sizes larger than 2 or 4 for the
1777 * 		checksum to update.
1778 *
1779 * 		A call to this helper is susceptible to change the underlying
1780 * 		packet buffer. Therefore, at load time, all checks on pointers
1781 * 		previously done by the verifier are invalidated and must be
1782 * 		performed again, if the helper is used in combination with
1783 * 		direct packet access.
1784 * 	Return
1785 * 		0 on success, or a negative error in case of failure.
1786 *
1787 * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
1788 * 	Description
1789 * 		This special helper is used to trigger a "tail call", or in
1790 * 		other words, to jump into another eBPF program. The same stack
1791 * 		frame is used (but values on stack and in registers for the
1792 * 		caller are not accessible to the callee). This mechanism allows
1793 * 		for program chaining, either for raising the maximum number of
1794 * 		available eBPF instructions, or to execute given programs in
1795 * 		conditional blocks. For security reasons, there is an upper
1796 * 		limit to the number of successive tail calls that can be
1797 * 		performed.
1798 *
1799 * 		Upon call of this helper, the program attempts to jump into a
1800 * 		program referenced at index *index* in *prog_array_map*, a
1801 * 		special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
1802 * 		*ctx*, a pointer to the context.
1803 *
1804 * 		If the call succeeds, the kernel immediately runs the first
1805 * 		instruction of the new program. This is not a function call,
1806 * 		and it never returns to the previous program. If the call
1807 * 		fails, then the helper has no effect, and the caller continues
1808 * 		to run its subsequent instructions. A call can fail if the
1809 * 		destination program for the jump does not exist (i.e. *index*
1810 * 		is superior to the number of entries in *prog_array_map*), or
1811 * 		if the maximum number of tail calls has been reached for this
1812 * 		chain of programs. This limit is defined in the kernel by the
1813 * 		macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
1814 *		which is currently set to 33.
1815 * 	Return
1816 * 		0 on success, or a negative error in case of failure.
1817 *
1818 * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1819 * 	Description
1820 * 		Clone and redirect the packet associated to *skb* to another
1821 * 		net device of index *ifindex*. Both ingress and egress
1822 * 		interfaces can be used for redirection. The **BPF_F_INGRESS**
1823 * 		value in *flags* is used to make the distinction (ingress path
1824 * 		is selected if the flag is present, egress path otherwise).
1825 * 		This is the only flag supported for now.
1826 *
1827 * 		In comparison with **bpf_redirect**\ () helper,
1828 * 		**bpf_clone_redirect**\ () has the associated cost of
1829 * 		duplicating the packet buffer, but this can be executed out of
1830 * 		the eBPF program. Conversely, **bpf_redirect**\ () is more
1831 * 		efficient, but it is handled through an action code where the
1832 * 		redirection happens only after the eBPF program has returned.
1833 *
1834 * 		A call to this helper is susceptible to change the underlying
1835 * 		packet buffer. Therefore, at load time, all checks on pointers
1836 * 		previously done by the verifier are invalidated and must be
1837 * 		performed again, if the helper is used in combination with
1838 * 		direct packet access.
1839 * 	Return
1840 * 		0 on success, or a negative error in case of failure.
1841 *
1842 * u64 bpf_get_current_pid_tgid(void)
1843 * 	Description
1844 * 		Get the current pid and tgid.
1845 * 	Return
1846 * 		A 64-bit integer containing the current tgid and pid, and
1847 * 		created as such:
1848 * 		*current_task*\ **->tgid << 32 \|**
1849 * 		*current_task*\ **->pid**.
1850 *
1851 * u64 bpf_get_current_uid_gid(void)
1852 * 	Description
1853 * 		Get the current uid and gid.
1854 * 	Return
1855 * 		A 64-bit integer containing the current GID and UID, and
1856 * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
1857 *
1858 * long bpf_get_current_comm(void *buf, u32 size_of_buf)
1859 * 	Description
1860 * 		Copy the **comm** attribute of the current task into *buf* of
1861 * 		*size_of_buf*. The **comm** attribute contains the name of
1862 * 		the executable (excluding the path) for the current task. The
1863 * 		*size_of_buf* must be strictly positive. On success, the
1864 * 		helper makes sure that the *buf* is NUL-terminated. On failure,
1865 * 		it is filled with zeroes.
1866 * 	Return
1867 * 		0 on success, or a negative error in case of failure.
1868 *
1869 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1870 * 	Description
1871 * 		Retrieve the classid for the current task, i.e. for the net_cls
1872 * 		cgroup to which *skb* belongs.
1873 *
1874 * 		This helper can be used on TC egress path, but not on ingress.
1875 *
1876 * 		The net_cls cgroup provides an interface to tag network packets
1877 * 		based on a user-provided identifier for all traffic coming from
1878 * 		the tasks belonging to the related cgroup. See also the related
1879 * 		kernel documentation, available from the Linux sources in file
1880 * 		*Documentation/admin-guide/cgroup-v1/net_cls.rst*.
1881 *
1882 * 		The Linux kernel has two versions for cgroups: there are
1883 * 		cgroups v1 and cgroups v2. Both are available to users, who can
1884 * 		use a mixture of them, but note that the net_cls cgroup is for
1885 * 		cgroup v1 only. This makes it incompatible with BPF programs
1886 * 		run on cgroups, which is a cgroup-v2-only feature (a socket can
1887 * 		only hold data for one version of cgroups at a time).
1888 *
1889 * 		This helper is only available is the kernel was compiled with
1890 * 		the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
1891 * 		"**y**" or to "**m**".
1892 * 	Return
1893 * 		The classid, or 0 for the default unconfigured classid.
1894 *
1895 * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1896 * 	Description
1897 * 		Push a *vlan_tci* (VLAN tag control information) of protocol
1898 * 		*vlan_proto* to the packet associated to *skb*, then update
1899 * 		the checksum. Note that if *vlan_proto* is different from
1900 * 		**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
1901 * 		be **ETH_P_8021Q**.
1902 *
1903 * 		A call to this helper is susceptible to change the underlying
1904 * 		packet buffer. Therefore, at load time, all checks on pointers
1905 * 		previously done by the verifier are invalidated and must be
1906 * 		performed again, if the helper is used in combination with
1907 * 		direct packet access.
1908 * 	Return
1909 * 		0 on success, or a negative error in case of failure.
1910 *
1911 * long bpf_skb_vlan_pop(struct sk_buff *skb)
1912 * 	Description
1913 * 		Pop a VLAN header from the packet associated to *skb*.
1914 *
1915 * 		A call to this helper is susceptible to change the underlying
1916 * 		packet buffer. Therefore, at load time, all checks on pointers
1917 * 		previously done by the verifier are invalidated and must be
1918 * 		performed again, if the helper is used in combination with
1919 * 		direct packet access.
1920 * 	Return
1921 * 		0 on success, or a negative error in case of failure.
1922 *
1923 * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1924 * 	Description
1925 * 		Get tunnel metadata. This helper takes a pointer *key* to an
1926 * 		empty **struct bpf_tunnel_key** of **size**, that will be
1927 * 		filled with tunnel metadata for the packet associated to *skb*.
1928 * 		The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
1929 * 		indicates that the tunnel is based on IPv6 protocol instead of
1930 * 		IPv4.
1931 *
1932 * 		The **struct bpf_tunnel_key** is an object that generalizes the
1933 * 		principal parameters used by various tunneling protocols into a
1934 * 		single struct. This way, it can be used to easily make a
1935 * 		decision based on the contents of the encapsulation header,
1936 * 		"summarized" in this struct. In particular, it holds the IP
1937 * 		address of the remote end (IPv4 or IPv6, depending on the case)
1938 * 		in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
1939 * 		this struct exposes the *key*\ **->tunnel_id**, which is
1940 * 		generally mapped to a VNI (Virtual Network Identifier), making
1941 * 		it programmable together with the **bpf_skb_set_tunnel_key**\
1942 * 		() helper.
1943 *
1944 * 		Let's imagine that the following code is part of a program
1945 * 		attached to the TC ingress interface, on one end of a GRE
1946 * 		tunnel, and is supposed to filter out all messages coming from
1947 * 		remote ends with IPv4 address other than 10.0.0.1:
1948 *
1949 * 		::
1950 *
1951 * 			int ret;
1952 * 			struct bpf_tunnel_key key = {};
1953 *
1954 * 			ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1955 * 			if (ret < 0)
1956 * 				return TC_ACT_SHOT;	// drop packet
1957 *
1958 * 			if (key.remote_ipv4 != 0x0a000001)
1959 * 				return TC_ACT_SHOT;	// drop packet
1960 *
1961 * 			return TC_ACT_OK;		// accept packet
1962 *
1963 * 		This interface can also be used with all encapsulation devices
1964 * 		that can operate in "collect metadata" mode: instead of having
1965 * 		one network device per specific configuration, the "collect
1966 * 		metadata" mode only requires a single device where the
1967 * 		configuration can be extracted from this helper.
1968 *
1969 * 		This can be used together with various tunnels such as VXLan,
1970 * 		Geneve, GRE or IP in IP (IPIP).
1971 * 	Return
1972 * 		0 on success, or a negative error in case of failure.
1973 *
1974 * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1975 * 	Description
1976 * 		Populate tunnel metadata for packet associated to *skb.* The
1977 * 		tunnel metadata is set to the contents of *key*, of *size*. The
1978 * 		*flags* can be set to a combination of the following values:
1979 *
1980 * 		**BPF_F_TUNINFO_IPV6**
1981 * 			Indicate that the tunnel is based on IPv6 protocol
1982 * 			instead of IPv4.
1983 * 		**BPF_F_ZERO_CSUM_TX**
1984 * 			For IPv4 packets, add a flag to tunnel metadata
1985 * 			indicating that checksum computation should be skipped
1986 * 			and checksum set to zeroes.
1987 * 		**BPF_F_DONT_FRAGMENT**
1988 * 			Add a flag to tunnel metadata indicating that the
1989 * 			packet should not be fragmented.
1990 * 		**BPF_F_SEQ_NUMBER**
1991 * 			Add a flag to tunnel metadata indicating that a
1992 * 			sequence number should be added to tunnel header before
1993 * 			sending the packet. This flag was added for GRE
1994 * 			encapsulation, but might be used with other protocols
1995 * 			as well in the future.
1996 *
1997 * 		Here is a typical usage on the transmit path:
1998 *
1999 * 		::
2000 *
2001 * 			struct bpf_tunnel_key key;
2002 * 			     populate key ...
2003 * 			bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
2004 * 			bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
2005 *
2006 * 		See also the description of the **bpf_skb_get_tunnel_key**\ ()
2007 * 		helper for additional information.
2008 * 	Return
2009 * 		0 on success, or a negative error in case of failure.
2010 *
2011 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
2012 * 	Description
2013 * 		Read the value of a perf event counter. This helper relies on a
2014 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
2015 * 		the perf event counter is selected when *map* is updated with
2016 * 		perf event file descriptors. The *map* is an array whose size
2017 * 		is the number of available CPUs, and each cell contains a value
2018 * 		relative to one CPU. The value to retrieve is indicated by
2019 * 		*flags*, that contains the index of the CPU to look up, masked
2020 * 		with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2021 * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
2022 * 		current CPU should be retrieved.
2023 *
2024 * 		Note that before Linux 4.13, only hardware perf event can be
2025 * 		retrieved.
2026 *
2027 * 		Also, be aware that the newer helper
2028 * 		**bpf_perf_event_read_value**\ () is recommended over
2029 * 		**bpf_perf_event_read**\ () in general. The latter has some ABI
2030 * 		quirks where error and counter value are used as a return code
2031 * 		(which is wrong to do since ranges may overlap). This issue is
2032 * 		fixed with **bpf_perf_event_read_value**\ (), which at the same
2033 * 		time provides more features over the **bpf_perf_event_read**\
2034 * 		() interface. Please refer to the description of
2035 * 		**bpf_perf_event_read_value**\ () for details.
2036 * 	Return
2037 * 		The value of the perf event counter read from the map, or a
2038 * 		negative error code in case of failure.
2039 *
2040 * long bpf_redirect(u32 ifindex, u64 flags)
2041 * 	Description
2042 * 		Redirect the packet to another net device of index *ifindex*.
2043 * 		This helper is somewhat similar to **bpf_clone_redirect**\
2044 * 		(), except that the packet is not cloned, which provides
2045 * 		increased performance.
2046 *
2047 * 		Except for XDP, both ingress and egress interfaces can be used
2048 * 		for redirection. The **BPF_F_INGRESS** value in *flags* is used
2049 * 		to make the distinction (ingress path is selected if the flag
2050 * 		is present, egress path otherwise). Currently, XDP only
2051 * 		supports redirection to the egress interface, and accepts no
2052 * 		flag at all.
2053 *
2054 * 		The same effect can also be attained with the more generic
2055 * 		**bpf_redirect_map**\ (), which uses a BPF map to store the
2056 * 		redirect target instead of providing it directly to the helper.
2057 * 	Return
2058 * 		For XDP, the helper returns **XDP_REDIRECT** on success or
2059 * 		**XDP_ABORTED** on error. For other program types, the values
2060 * 		are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
2061 * 		error.
2062 *
2063 * u32 bpf_get_route_realm(struct sk_buff *skb)
2064 * 	Description
2065 * 		Retrieve the realm or the route, that is to say the
2066 * 		**tclassid** field of the destination for the *skb*. The
2067 * 		identifier retrieved is a user-provided tag, similar to the
2068 * 		one used with the net_cls cgroup (see description for
2069 * 		**bpf_get_cgroup_classid**\ () helper), but here this tag is
2070 * 		held by a route (a destination entry), not by a task.
2071 *
2072 * 		Retrieving this identifier works with the clsact TC egress hook
2073 * 		(see also **tc-bpf(8)**), or alternatively on conventional
2074 * 		classful egress qdiscs, but not on TC ingress path. In case of
2075 * 		clsact TC egress hook, this has the advantage that, internally,
2076 * 		the destination entry has not been dropped yet in the transmit
2077 * 		path. Therefore, the destination entry does not need to be
2078 * 		artificially held via **netif_keep_dst**\ () for a classful
2079 * 		qdisc until the *skb* is freed.
2080 *
2081 * 		This helper is available only if the kernel was compiled with
2082 * 		**CONFIG_IP_ROUTE_CLASSID** configuration option.
2083 * 	Return
2084 * 		The realm of the route for the packet associated to *skb*, or 0
2085 * 		if none was found.
2086 *
2087 * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2088 * 	Description
2089 * 		Write raw *data* blob into a special BPF perf event held by
2090 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2091 * 		event must have the following attributes: **PERF_SAMPLE_RAW**
2092 * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2093 * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2094 *
2095 * 		The *flags* are used to indicate the index in *map* for which
2096 * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
2097 * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2098 * 		to indicate that the index of the current CPU core should be
2099 * 		used.
2100 *
2101 * 		The value to write, of *size*, is passed through eBPF stack and
2102 * 		pointed by *data*.
2103 *
2104 * 		The context of the program *ctx* needs also be passed to the
2105 * 		helper.
2106 *
2107 * 		On user space, a program willing to read the values needs to
2108 * 		call **perf_event_open**\ () on the perf event (either for
2109 * 		one or for all CPUs) and to store the file descriptor into the
2110 * 		*map*. This must be done before the eBPF program can send data
2111 * 		into it. An example is available in file
2112 * 		*samples/bpf/trace_output_user.c* in the Linux kernel source
2113 * 		tree (the eBPF program counterpart is in
2114 * 		*samples/bpf/trace_output_kern.c*).
2115 *
2116 * 		**bpf_perf_event_output**\ () achieves better performance
2117 * 		than **bpf_trace_printk**\ () for sharing data with user
2118 * 		space, and is much better suitable for streaming data from eBPF
2119 * 		programs.
2120 *
2121 * 		Note that this helper is not restricted to tracing use cases
2122 * 		and can be used with programs attached to TC or XDP as well,
2123 * 		where it allows for passing data to user space listeners. Data
2124 * 		can be:
2125 *
2126 * 		* Only custom structs,
2127 * 		* Only the packet payload, or
2128 * 		* A combination of both.
2129 * 	Return
2130 * 		0 on success, or a negative error in case of failure.
2131 *
2132 * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
2133 * 	Description
2134 * 		This helper was provided as an easy way to load data from a
2135 * 		packet. It can be used to load *len* bytes from *offset* from
2136 * 		the packet associated to *skb*, into the buffer pointed by
2137 * 		*to*.
2138 *
2139 * 		Since Linux 4.7, usage of this helper has mostly been replaced
2140 * 		by "direct packet access", enabling packet data to be
2141 * 		manipulated with *skb*\ **->data** and *skb*\ **->data_end**
2142 * 		pointing respectively to the first byte of packet data and to
2143 * 		the byte after the last byte of packet data. However, it
2144 * 		remains useful if one wishes to read large quantities of data
2145 * 		at once from a packet into the eBPF stack.
2146 * 	Return
2147 * 		0 on success, or a negative error in case of failure.
2148 *
2149 * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
2150 * 	Description
2151 * 		Walk a user or a kernel stack and return its id. To achieve
2152 * 		this, the helper needs *ctx*, which is a pointer to the context
2153 * 		on which the tracing program is executed, and a pointer to a
2154 * 		*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
2155 *
2156 * 		The last argument, *flags*, holds the number of stack frames to
2157 * 		skip (from 0 to 255), masked with
2158 * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2159 * 		a combination of the following flags:
2160 *
2161 * 		**BPF_F_USER_STACK**
2162 * 			Collect a user space stack instead of a kernel stack.
2163 * 		**BPF_F_FAST_STACK_CMP**
2164 * 			Compare stacks by hash only.
2165 * 		**BPF_F_REUSE_STACKID**
2166 * 			If two different stacks hash into the same *stackid*,
2167 * 			discard the old one.
2168 *
2169 * 		The stack id retrieved is a 32 bit long integer handle which
2170 * 		can be further combined with other data (including other stack
2171 * 		ids) and used as a key into maps. This can be useful for
2172 * 		generating a variety of graphs (such as flame graphs or off-cpu
2173 * 		graphs).
2174 *
2175 * 		For walking a stack, this helper is an improvement over
2176 * 		**bpf_probe_read**\ (), which can be used with unrolled loops
2177 * 		but is not efficient and consumes a lot of eBPF instructions.
2178 * 		Instead, **bpf_get_stackid**\ () can collect up to
2179 * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
2180 * 		this limit can be controlled with the **sysctl** program, and
2181 * 		that it should be manually increased in order to profile long
2182 * 		user stacks (such as stacks for Java programs). To do so, use:
2183 *
2184 * 		::
2185 *
2186 * 			# sysctl kernel.perf_event_max_stack=<new value>
2187 * 	Return
2188 * 		The positive or null stack id on success, or a negative error
2189 * 		in case of failure.
2190 *
2191 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
2192 * 	Description
2193 * 		Compute a checksum difference, from the raw buffer pointed by
2194 * 		*from*, of length *from_size* (that must be a multiple of 4),
2195 * 		towards the raw buffer pointed by *to*, of size *to_size*
2196 * 		(same remark). An optional *seed* can be added to the value
2197 * 		(this can be cascaded, the seed may come from a previous call
2198 * 		to the helper).
2199 *
2200 * 		This is flexible enough to be used in several ways:
2201 *
2202 * 		* With *from_size* == 0, *to_size* > 0 and *seed* set to
2203 * 		  checksum, it can be used when pushing new data.
2204 * 		* With *from_size* > 0, *to_size* == 0 and *seed* set to
2205 * 		  checksum, it can be used when removing data from a packet.
2206 * 		* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
2207 * 		  can be used to compute a diff. Note that *from_size* and
2208 * 		  *to_size* do not need to be equal.
2209 *
2210 * 		This helper can be used in combination with
2211 * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
2212 * 		which one can feed in the difference computed with
2213 * 		**bpf_csum_diff**\ ().
2214 * 	Return
2215 * 		The checksum result, or a negative error code in case of
2216 * 		failure.
2217 *
2218 * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2219 * 	Description
2220 * 		Retrieve tunnel options metadata for the packet associated to
2221 * 		*skb*, and store the raw tunnel option data to the buffer *opt*
2222 * 		of *size*.
2223 *
2224 * 		This helper can be used with encapsulation devices that can
2225 * 		operate in "collect metadata" mode (please refer to the related
2226 * 		note in the description of **bpf_skb_get_tunnel_key**\ () for
2227 * 		more details). A particular example where this can be used is
2228 * 		in combination with the Geneve encapsulation protocol, where it
2229 * 		allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
2230 * 		and retrieving arbitrary TLVs (Type-Length-Value headers) from
2231 * 		the eBPF program. This allows for full customization of these
2232 * 		headers.
2233 * 	Return
2234 * 		The size of the option data retrieved.
2235 *
2236 * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2237 * 	Description
2238 * 		Set tunnel options metadata for the packet associated to *skb*
2239 * 		to the option data contained in the raw buffer *opt* of *size*.
2240 *
2241 * 		See also the description of the **bpf_skb_get_tunnel_opt**\ ()
2242 * 		helper for additional information.
2243 * 	Return
2244 * 		0 on success, or a negative error in case of failure.
2245 *
2246 * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2247 * 	Description
2248 * 		Change the protocol of the *skb* to *proto*. Currently
2249 * 		supported are transition from IPv4 to IPv6, and from IPv6 to
2250 * 		IPv4. The helper takes care of the groundwork for the
2251 * 		transition, including resizing the socket buffer. The eBPF
2252 * 		program is expected to fill the new headers, if any, via
2253 * 		**skb_store_bytes**\ () and to recompute the checksums with
2254 * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
2255 * 		(). The main case for this helper is to perform NAT64
2256 * 		operations out of an eBPF program.
2257 *
2258 * 		Internally, the GSO type is marked as dodgy so that headers are
2259 * 		checked and segments are recalculated by the GSO/GRO engine.
2260 * 		The size for GSO target is adapted as well.
2261 *
2262 * 		All values for *flags* are reserved for future usage, and must
2263 * 		be left at zero.
2264 *
2265 * 		A call to this helper is susceptible to change the underlying
2266 * 		packet buffer. Therefore, at load time, all checks on pointers
2267 * 		previously done by the verifier are invalidated and must be
2268 * 		performed again, if the helper is used in combination with
2269 * 		direct packet access.
2270 * 	Return
2271 * 		0 on success, or a negative error in case of failure.
2272 *
2273 * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2274 * 	Description
2275 * 		Change the packet type for the packet associated to *skb*. This
2276 * 		comes down to setting *skb*\ **->pkt_type** to *type*, except
2277 * 		the eBPF program does not have a write access to *skb*\
2278 * 		**->pkt_type** beside this helper. Using a helper here allows
2279 * 		for graceful handling of errors.
2280 *
2281 * 		The major use case is to change incoming *skb*s to
2282 * 		**PACKET_HOST** in a programmatic way instead of having to
2283 * 		recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
2284 * 		example.
2285 *
2286 * 		Note that *type* only allows certain values. At this time, they
2287 * 		are:
2288 *
2289 * 		**PACKET_HOST**
2290 * 			Packet is for us.
2291 * 		**PACKET_BROADCAST**
2292 * 			Send packet to all.
2293 * 		**PACKET_MULTICAST**
2294 * 			Send packet to group.
2295 * 		**PACKET_OTHERHOST**
2296 * 			Send packet to someone else.
2297 * 	Return
2298 * 		0 on success, or a negative error in case of failure.
2299 *
2300 * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
2301 * 	Description
2302 * 		Check whether *skb* is a descendant of the cgroup2 held by
2303 * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2304 * 	Return
2305 * 		The return value depends on the result of the test, and can be:
2306 *
2307 * 		* 0, if the *skb* failed the cgroup2 descendant test.
2308 * 		* 1, if the *skb* succeeded the cgroup2 descendant test.
2309 * 		* A negative error code, if an error occurred.
2310 *
2311 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
2312 * 	Description
2313 * 		Retrieve the hash of the packet, *skb*\ **->hash**. If it is
2314 * 		not set, in particular if the hash was cleared due to mangling,
2315 * 		recompute this hash. Later accesses to the hash can be done
2316 * 		directly with *skb*\ **->hash**.
2317 *
2318 * 		Calling **bpf_set_hash_invalid**\ (), changing a packet
2319 * 		prototype with **bpf_skb_change_proto**\ (), or calling
2320 * 		**bpf_skb_store_bytes**\ () with the
2321 * 		**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
2322 * 		the hash and to trigger a new computation for the next call to
2323 * 		**bpf_get_hash_recalc**\ ().
2324 * 	Return
2325 * 		The 32-bit hash.
2326 *
2327 * u64 bpf_get_current_task(void)
2328 * 	Description
2329 * 		Get the current task.
2330 * 	Return
2331 * 		A pointer to the current task struct.
2332 *
2333 * long bpf_probe_write_user(void *dst, const void *src, u32 len)
2334 * 	Description
2335 * 		Attempt in a safe way to write *len* bytes from the buffer
2336 * 		*src* to *dst* in memory. It only works for threads that are in
2337 * 		user context, and *dst* must be a valid user space address.
2338 *
2339 * 		This helper should not be used to implement any kind of
2340 * 		security mechanism because of TOC-TOU attacks, but rather to
2341 * 		debug, divert, and manipulate execution of semi-cooperative
2342 * 		processes.
2343 *
2344 * 		Keep in mind that this feature is meant for experiments, and it
2345 * 		has a risk of crashing the system and running programs.
2346 * 		Therefore, when an eBPF program using this helper is attached,
2347 * 		a warning including PID and process name is printed to kernel
2348 * 		logs.
2349 * 	Return
2350 * 		0 on success, or a negative error in case of failure.
2351 *
2352 * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2353 * 	Description
2354 * 		Check whether the probe is being run is the context of a given
2355 * 		subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2356 * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2357 * 	Return
2358 * 		The return value depends on the result of the test, and can be:
2359 *
2360 *		* 1, if current task belongs to the cgroup2.
2361 *		* 0, if current task does not belong to the cgroup2.
2362 * 		* A negative error code, if an error occurred.
2363 *
2364 * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2365 * 	Description
2366 * 		Resize (trim or grow) the packet associated to *skb* to the
2367 * 		new *len*. The *flags* are reserved for future usage, and must
2368 * 		be left at zero.
2369 *
2370 * 		The basic idea is that the helper performs the needed work to
2371 * 		change the size of the packet, then the eBPF program rewrites
2372 * 		the rest via helpers like **bpf_skb_store_bytes**\ (),
2373 * 		**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
2374 * 		and others. This helper is a slow path utility intended for
2375 * 		replies with control messages. And because it is targeted for
2376 * 		slow path, the helper itself can afford to be slow: it
2377 * 		implicitly linearizes, unclones and drops offloads from the
2378 * 		*skb*.
2379 *
2380 * 		A call to this helper is susceptible to change the underlying
2381 * 		packet buffer. Therefore, at load time, all checks on pointers
2382 * 		previously done by the verifier are invalidated and must be
2383 * 		performed again, if the helper is used in combination with
2384 * 		direct packet access.
2385 * 	Return
2386 * 		0 on success, or a negative error in case of failure.
2387 *
2388 * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2389 * 	Description
2390 * 		Pull in non-linear data in case the *skb* is non-linear and not
2391 * 		all of *len* are part of the linear section. Make *len* bytes
2392 * 		from *skb* readable and writable. If a zero value is passed for
2393 *		*len*, then all bytes in the linear part of *skb* will be made
2394 *		readable and writable.
2395 *
2396 * 		This helper is only needed for reading and writing with direct
2397 * 		packet access.
2398 *
2399 * 		For direct packet access, testing that offsets to access
2400 * 		are within packet boundaries (test on *skb*\ **->data_end**) is
2401 * 		susceptible to fail if offsets are invalid, or if the requested
2402 * 		data is in non-linear parts of the *skb*. On failure the
2403 * 		program can just bail out, or in the case of a non-linear
2404 * 		buffer, use a helper to make the data available. The
2405 * 		**bpf_skb_load_bytes**\ () helper is a first solution to access
2406 * 		the data. Another one consists in using **bpf_skb_pull_data**
2407 * 		to pull in once the non-linear parts, then retesting and
2408 * 		eventually access the data.
2409 *
2410 * 		At the same time, this also makes sure the *skb* is uncloned,
2411 * 		which is a necessary condition for direct write. As this needs
2412 * 		to be an invariant for the write part only, the verifier
2413 * 		detects writes and adds a prologue that is calling
2414 * 		**bpf_skb_pull_data()** to effectively unclone the *skb* from
2415 * 		the very beginning in case it is indeed cloned.
2416 *
2417 * 		A call to this helper is susceptible to change the underlying
2418 * 		packet buffer. Therefore, at load time, all checks on pointers
2419 * 		previously done by the verifier are invalidated and must be
2420 * 		performed again, if the helper is used in combination with
2421 * 		direct packet access.
2422 * 	Return
2423 * 		0 on success, or a negative error in case of failure.
2424 *
2425 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2426 * 	Description
2427 * 		Add the checksum *csum* into *skb*\ **->csum** in case the
2428 * 		driver has supplied a checksum for the entire packet into that
2429 * 		field. Return an error otherwise. This helper is intended to be
2430 * 		used in combination with **bpf_csum_diff**\ (), in particular
2431 * 		when the checksum needs to be updated after data has been
2432 * 		written into the packet through direct packet access.
2433 * 	Return
2434 * 		The checksum on success, or a negative error code in case of
2435 * 		failure.
2436 *
2437 * void bpf_set_hash_invalid(struct sk_buff *skb)
2438 * 	Description
2439 * 		Invalidate the current *skb*\ **->hash**. It can be used after
2440 * 		mangling on headers through direct packet access, in order to
2441 * 		indicate that the hash is outdated and to trigger a
2442 * 		recalculation the next time the kernel tries to access this
2443 * 		hash or when the **bpf_get_hash_recalc**\ () helper is called.
2444 * 	Return
2445 * 		void.
2446 *
2447 * long bpf_get_numa_node_id(void)
2448 * 	Description
2449 * 		Return the id of the current NUMA node. The primary use case
2450 * 		for this helper is the selection of sockets for the local NUMA
2451 * 		node, when the program is attached to sockets using the
2452 * 		**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
2453 * 		but the helper is also available to other eBPF program types,
2454 * 		similarly to **bpf_get_smp_processor_id**\ ().
2455 * 	Return
2456 * 		The id of current NUMA node.
2457 *
2458 * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2459 * 	Description
2460 * 		Grows headroom of packet associated to *skb* and adjusts the
2461 * 		offset of the MAC header accordingly, adding *len* bytes of
2462 * 		space. It automatically extends and reallocates memory as
2463 * 		required.
2464 *
2465 * 		This helper can be used on a layer 3 *skb* to push a MAC header
2466 * 		for redirection into a layer 2 device.
2467 *
2468 * 		All values for *flags* are reserved for future usage, and must
2469 * 		be left at zero.
2470 *
2471 * 		A call to this helper is susceptible to change the underlying
2472 * 		packet buffer. Therefore, at load time, all checks on pointers
2473 * 		previously done by the verifier are invalidated and must be
2474 * 		performed again, if the helper is used in combination with
2475 * 		direct packet access.
2476 * 	Return
2477 * 		0 on success, or a negative error in case of failure.
2478 *
2479 * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2480 * 	Description
2481 * 		Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
2482 * 		it is possible to use a negative value for *delta*. This helper
2483 * 		can be used to prepare the packet for pushing or popping
2484 * 		headers.
2485 *
2486 * 		A call to this helper is susceptible to change the underlying
2487 * 		packet buffer. Therefore, at load time, all checks on pointers
2488 * 		previously done by the verifier are invalidated and must be
2489 * 		performed again, if the helper is used in combination with
2490 * 		direct packet access.
2491 * 	Return
2492 * 		0 on success, or a negative error in case of failure.
2493 *
2494 * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
2495 * 	Description
2496 * 		Copy a NUL terminated string from an unsafe kernel address
2497 * 		*unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
2498 * 		more details.
2499 *
2500 * 		Generally, use **bpf_probe_read_user_str**\ () or
2501 * 		**bpf_probe_read_kernel_str**\ () instead.
2502 * 	Return
2503 * 		On success, the strictly positive length of the string,
2504 * 		including the trailing NUL character. On error, a negative
2505 * 		value.
2506 *
2507 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
2508 * 	Description
2509 * 		If the **struct sk_buff** pointed by *skb* has a known socket,
2510 * 		retrieve the cookie (generated by the kernel) of this socket.
2511 * 		If no cookie has been set yet, generate a new cookie. Once
2512 * 		generated, the socket cookie remains stable for the life of the
2513 * 		socket. This helper can be useful for monitoring per socket
2514 * 		networking traffic statistics as it provides a global socket
2515 * 		identifier that can be assumed unique.
2516 * 	Return
2517 * 		A 8-byte long unique number on success, or 0 if the socket
2518 * 		field is missing inside *skb*.
2519 *
2520 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2521 * 	Description
2522 * 		Equivalent to bpf_get_socket_cookie() helper that accepts
2523 * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
2524 * 	Return
2525 * 		A 8-byte long unique number.
2526 *
2527 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2528 * 	Description
2529 * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2530 * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
2531 * 	Return
2532 * 		A 8-byte long unique number.
2533 *
2534 * u64 bpf_get_socket_cookie(struct sock *sk)
2535 * 	Description
2536 * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2537 * 		*sk*, but gets socket from a BTF **struct sock**. This helper
2538 * 		also works for sleepable programs.
2539 * 	Return
2540 * 		A 8-byte long unique number or 0 if *sk* is NULL.
2541 *
2542 * u32 bpf_get_socket_uid(struct sk_buff *skb)
2543 * 	Description
2544 * 		Get the owner UID of the socked associated to *skb*.
2545 * 	Return
2546 * 		The owner UID of the socket associated to *skb*. If the socket
2547 * 		is **NULL**, or if it is not a full socket (i.e. if it is a
2548 * 		time-wait or a request socket instead), **overflowuid** value
2549 * 		is returned (note that **overflowuid** might also be the actual
2550 * 		UID value for the socket).
2551 *
2552 * long bpf_set_hash(struct sk_buff *skb, u32 hash)
2553 * 	Description
2554 * 		Set the full hash for *skb* (set the field *skb*\ **->hash**)
2555 * 		to value *hash*.
2556 * 	Return
2557 * 		0
2558 *
2559 * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2560 * 	Description
2561 * 		Emulate a call to **setsockopt()** on the socket associated to
2562 * 		*bpf_socket*, which must be a full socket. The *level* at
2563 * 		which the option resides and the name *optname* of the option
2564 * 		must be specified, see **setsockopt(2)** for more information.
2565 * 		The option value of length *optlen* is pointed by *optval*.
2566 *
2567 * 		*bpf_socket* should be one of the following:
2568 *
2569 * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2570 * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2571 * 		  and **BPF_CGROUP_INET6_CONNECT**.
2572 *
2573 * 		This helper actually implements a subset of **setsockopt()**.
2574 * 		It supports the following *level*\ s:
2575 *
2576 * 		* **SOL_SOCKET**, which supports the following *optname*\ s:
2577 * 		  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
2578 * 		  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
2579 * 		  **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
2580 * 		* **IPPROTO_TCP**, which supports the following *optname*\ s:
2581 * 		  **TCP_CONGESTION**, **TCP_BPF_IW**,
2582 * 		  **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
2583 * 		  **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
2584 *		  **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
2585 * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2586 * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2587 * 	Return
2588 * 		0 on success, or a negative error in case of failure.
2589 *
2590 * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2591 * 	Description
2592 * 		Grow or shrink the room for data in the packet associated to
2593 * 		*skb* by *len_diff*, and according to the selected *mode*.
2594 *
2595 * 		By default, the helper will reset any offloaded checksum
2596 * 		indicator of the skb to CHECKSUM_NONE. This can be avoided
2597 * 		by the following flag:
2598 *
2599 * 		* **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
2600 * 		  checksum data of the skb to CHECKSUM_NONE.
2601 *
2602 *		There are two supported modes at this time:
2603 *
2604 *		* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
2605 * 		  (room space is added or removed between the layer 2 and
2606 * 		  layer 3 headers).
2607 *
2608 * 		* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
2609 * 		  (room space is added or removed between the layer 3 and
2610 * 		  layer 4 headers).
2611 *
2612 *		The following flags are supported at this time:
2613 *
2614 *		* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
2615 *		  Adjusting mss in this way is not allowed for datagrams.
2616 *
2617 *		* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
2618 *		  **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
2619 *		  Any new space is reserved to hold a tunnel header.
2620 *		  Configure skb offsets and other fields accordingly.
2621 *
2622 *		* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
2623 *		  **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
2624 *		  Use with ENCAP_L3 flags to further specify the tunnel type.
2625 *
2626 *		* **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
2627 *		  Use with ENCAP_L3/L4 flags to further specify the tunnel
2628 *		  type; *len* is the length of the inner MAC header.
2629 *
2630 *		* **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
2631 *		  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2632 *		  L2 type as Ethernet.
2633 *
2634 * 		A call to this helper is susceptible to change the underlying
2635 * 		packet buffer. Therefore, at load time, all checks on pointers
2636 * 		previously done by the verifier are invalidated and must be
2637 * 		performed again, if the helper is used in combination with
2638 * 		direct packet access.
2639 * 	Return
2640 * 		0 on success, or a negative error in case of failure.
2641 *
2642 * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2643 * 	Description
2644 * 		Redirect the packet to the endpoint referenced by *map* at
2645 * 		index *key*. Depending on its type, this *map* can contain
2646 * 		references to net devices (for forwarding packets through other
2647 * 		ports), or to CPUs (for redirecting XDP frames to another CPU;
2648 * 		but this is only implemented for native XDP (with driver
2649 * 		support) as of this writing).
2650 *
2651 * 		The lower two bits of *flags* are used as the return code if
2652 * 		the map lookup fails. This is so that the return value can be
2653 * 		one of the XDP program return codes up to **XDP_TX**, as chosen
2654 * 		by the caller. The higher bits of *flags* can be set to
2655 * 		BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2656 *
2657 * 		With BPF_F_BROADCAST the packet will be broadcasted to all the
2658 * 		interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2659 * 		interface will be excluded when do broadcasting.
2660 *
2661 * 		See also **bpf_redirect**\ (), which only supports redirecting
2662 * 		to an ifindex, but doesn't require a map to do so.
2663 * 	Return
2664 * 		**XDP_REDIRECT** on success, or the value of the two lower bits
2665 * 		of the *flags* argument on error.
2666 *
2667 * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
2668 * 	Description
2669 * 		Redirect the packet to the socket referenced by *map* (of type
2670 * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2671 * 		egress interfaces can be used for redirection. The
2672 * 		**BPF_F_INGRESS** value in *flags* is used to make the
2673 * 		distinction (ingress path is selected if the flag is present,
2674 * 		egress path otherwise). This is the only flag supported for now.
2675 * 	Return
2676 * 		**SK_PASS** on success, or **SK_DROP** on error.
2677 *
2678 * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2679 * 	Description
2680 * 		Add an entry to, or update a *map* referencing sockets. The
2681 * 		*skops* is used as a new value for the entry associated to
2682 * 		*key*. *flags* is one of:
2683 *
2684 * 		**BPF_NOEXIST**
2685 * 			The entry for *key* must not exist in the map.
2686 * 		**BPF_EXIST**
2687 * 			The entry for *key* must already exist in the map.
2688 * 		**BPF_ANY**
2689 * 			No condition on the existence of the entry for *key*.
2690 *
2691 * 		If the *map* has eBPF programs (parser and verdict), those will
2692 * 		be inherited by the socket being added. If the socket is
2693 * 		already attached to eBPF programs, this results in an error.
2694 * 	Return
2695 * 		0 on success, or a negative error in case of failure.
2696 *
2697 * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2698 * 	Description
2699 * 		Adjust the address pointed by *xdp_md*\ **->data_meta** by
2700 * 		*delta* (which can be positive or negative). Note that this
2701 * 		operation modifies the address stored in *xdp_md*\ **->data**,
2702 * 		so the latter must be loaded only after the helper has been
2703 * 		called.
2704 *
2705 * 		The use of *xdp_md*\ **->data_meta** is optional and programs
2706 * 		are not required to use it. The rationale is that when the
2707 * 		packet is processed with XDP (e.g. as DoS filter), it is
2708 * 		possible to push further meta data along with it before passing
2709 * 		to the stack, and to give the guarantee that an ingress eBPF
2710 * 		program attached as a TC classifier on the same device can pick
2711 * 		this up for further post-processing. Since TC works with socket
2712 * 		buffers, it remains possible to set from XDP the **mark** or
2713 * 		**priority** pointers, or other pointers for the socket buffer.
2714 * 		Having this scratch space generic and programmable allows for
2715 * 		more flexibility as the user is free to store whatever meta
2716 * 		data they need.
2717 *
2718 * 		A call to this helper is susceptible to change the underlying
2719 * 		packet buffer. Therefore, at load time, all checks on pointers
2720 * 		previously done by the verifier are invalidated and must be
2721 * 		performed again, if the helper is used in combination with
2722 * 		direct packet access.
2723 * 	Return
2724 * 		0 on success, or a negative error in case of failure.
2725 *
2726 * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
2727 * 	Description
2728 * 		Read the value of a perf event counter, and store it into *buf*
2729 * 		of size *buf_size*. This helper relies on a *map* of type
2730 * 		**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
2731 * 		counter is selected when *map* is updated with perf event file
2732 * 		descriptors. The *map* is an array whose size is the number of
2733 * 		available CPUs, and each cell contains a value relative to one
2734 * 		CPU. The value to retrieve is indicated by *flags*, that
2735 * 		contains the index of the CPU to look up, masked with
2736 * 		**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2737 * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
2738 * 		current CPU should be retrieved.
2739 *
2740 * 		This helper behaves in a way close to
2741 * 		**bpf_perf_event_read**\ () helper, save that instead of
2742 * 		just returning the value observed, it fills the *buf*
2743 * 		structure. This allows for additional data to be retrieved: in
2744 * 		particular, the enabled and running times (in *buf*\
2745 * 		**->enabled** and *buf*\ **->running**, respectively) are
2746 * 		copied. In general, **bpf_perf_event_read_value**\ () is
2747 * 		recommended over **bpf_perf_event_read**\ (), which has some
2748 * 		ABI issues and provides fewer functionalities.
2749 *
2750 * 		These values are interesting, because hardware PMU (Performance
2751 * 		Monitoring Unit) counters are limited resources. When there are
2752 * 		more PMU based perf events opened than available counters,
2753 * 		kernel will multiplex these events so each event gets certain
2754 * 		percentage (but not all) of the PMU time. In case that
2755 * 		multiplexing happens, the number of samples or counter value
2756 * 		will not reflect the case compared to when no multiplexing
2757 * 		occurs. This makes comparison between different runs difficult.
2758 * 		Typically, the counter value should be normalized before
2759 * 		comparing to other experiments. The usual normalization is done
2760 * 		as follows.
2761 *
2762 * 		::
2763 *
2764 * 			normalized_counter = counter * t_enabled / t_running
2765 *
2766 * 		Where t_enabled is the time enabled for event and t_running is
2767 * 		the time running for event since last normalization. The
2768 * 		enabled and running times are accumulated since the perf event
2769 * 		open. To achieve scaling factor between two invocations of an
2770 * 		eBPF program, users can use CPU id as the key (which is
2771 * 		typical for perf array usage model) to remember the previous
2772 * 		value and do the calculation inside the eBPF program.
2773 * 	Return
2774 * 		0 on success, or a negative error in case of failure.
2775 *
2776 * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
2777 * 	Description
2778 * 		For en eBPF program attached to a perf event, retrieve the
2779 * 		value of the event counter associated to *ctx* and store it in
2780 * 		the structure pointed by *buf* and of size *buf_size*. Enabled
2781 * 		and running times are also stored in the structure (see
2782 * 		description of helper **bpf_perf_event_read_value**\ () for
2783 * 		more details).
2784 * 	Return
2785 * 		0 on success, or a negative error in case of failure.
2786 *
2787 * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2788 * 	Description
2789 * 		Emulate a call to **getsockopt()** on the socket associated to
2790 * 		*bpf_socket*, which must be a full socket. The *level* at
2791 * 		which the option resides and the name *optname* of the option
2792 * 		must be specified, see **getsockopt(2)** for more information.
2793 * 		The retrieved value is stored in the structure pointed by
2794 * 		*opval* and of length *optlen*.
2795 *
2796 * 		*bpf_socket* should be one of the following:
2797 *
2798 * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2799 * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2800 * 		  and **BPF_CGROUP_INET6_CONNECT**.
2801 *
2802 * 		This helper actually implements a subset of **getsockopt()**.
2803 * 		It supports the following *level*\ s:
2804 *
2805 * 		* **IPPROTO_TCP**, which supports *optname*
2806 * 		  **TCP_CONGESTION**.
2807 * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2808 * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2809 * 	Return
2810 * 		0 on success, or a negative error in case of failure.
2811 *
2812 * long bpf_override_return(struct pt_regs *regs, u64 rc)
2813 * 	Description
2814 * 		Used for error injection, this helper uses kprobes to override
2815 * 		the return value of the probed function, and to set it to *rc*.
2816 * 		The first argument is the context *regs* on which the kprobe
2817 * 		works.
2818 *
2819 * 		This helper works by setting the PC (program counter)
2820 * 		to an override function which is run in place of the original
2821 * 		probed function. This means the probed function is not run at
2822 * 		all. The replacement function just returns with the required
2823 * 		value.
2824 *
2825 * 		This helper has security implications, and thus is subject to
2826 * 		restrictions. It is only available if the kernel was compiled
2827 * 		with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
2828 * 		option, and in this case it only works on functions tagged with
2829 * 		**ALLOW_ERROR_INJECTION** in the kernel code.
2830 *
2831 * 		Also, the helper is only available for the architectures having
2832 * 		the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2833 * 		x86 architecture is the only one to support this feature.
2834 * 	Return
2835 * 		0
2836 *
2837 * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2838 * 	Description
2839 * 		Attempt to set the value of the **bpf_sock_ops_cb_flags** field
2840 * 		for the full TCP socket associated to *bpf_sock_ops* to
2841 * 		*argval*.
2842 *
2843 * 		The primary use of this field is to determine if there should
2844 * 		be calls to eBPF programs of type
2845 * 		**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
2846 * 		code. A program of the same type can change its value, per
2847 * 		connection and as necessary, when the connection is
2848 * 		established. This field is directly accessible for reading, but
2849 * 		this helper must be used for updates in order to return an
2850 * 		error if an eBPF program tries to set a callback that is not
2851 * 		supported in the current kernel.
2852 *
2853 * 		*argval* is a flag array which can combine these flags:
2854 *
2855 * 		* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
2856 * 		* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
2857 * 		* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
2858 * 		* **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
2859 *
2860 * 		Therefore, this function can be used to clear a callback flag by
2861 * 		setting the appropriate bit to zero. e.g. to disable the RTO
2862 * 		callback:
2863 *
2864 * 		**bpf_sock_ops_cb_flags_set(bpf_sock,**
2865 * 			**bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
2866 *
2867 * 		Here are some examples of where one could call such eBPF
2868 * 		program:
2869 *
2870 * 		* When RTO fires.
2871 * 		* When a packet is retransmitted.
2872 * 		* When the connection terminates.
2873 * 		* When a packet is sent.
2874 * 		* When a packet is received.
2875 * 	Return
2876 * 		Code **-EINVAL** if the socket is not a full TCP socket;
2877 * 		otherwise, a positive number containing the bits that could not
2878 * 		be set is returned (which comes down to 0 if all bits were set
2879 * 		as required).
2880 *
2881 * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
2882 * 	Description
2883 * 		This helper is used in programs implementing policies at the
2884 * 		socket level. If the message *msg* is allowed to pass (i.e. if
2885 * 		the verdict eBPF program returns **SK_PASS**), redirect it to
2886 * 		the socket referenced by *map* (of type
2887 * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2888 * 		egress interfaces can be used for redirection. The
2889 * 		**BPF_F_INGRESS** value in *flags* is used to make the
2890 * 		distinction (ingress path is selected if the flag is present,
2891 * 		egress path otherwise). This is the only flag supported for now.
2892 * 	Return
2893 * 		**SK_PASS** on success, or **SK_DROP** on error.
2894 *
2895 * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2896 * 	Description
2897 * 		For socket policies, apply the verdict of the eBPF program to
2898 * 		the next *bytes* (number of bytes) of message *msg*.
2899 *
2900 * 		For example, this helper can be used in the following cases:
2901 *
2902 * 		* A single **sendmsg**\ () or **sendfile**\ () system call
2903 * 		  contains multiple logical messages that the eBPF program is
2904 * 		  supposed to read and for which it should apply a verdict.
2905 * 		* An eBPF program only cares to read the first *bytes* of a
2906 * 		  *msg*. If the message has a large payload, then setting up
2907 * 		  and calling the eBPF program repeatedly for all bytes, even
2908 * 		  though the verdict is already known, would create unnecessary
2909 * 		  overhead.
2910 *
2911 * 		When called from within an eBPF program, the helper sets a
2912 * 		counter internal to the BPF infrastructure, that is used to
2913 * 		apply the last verdict to the next *bytes*. If *bytes* is
2914 * 		smaller than the current data being processed from a
2915 * 		**sendmsg**\ () or **sendfile**\ () system call, the first
2916 * 		*bytes* will be sent and the eBPF program will be re-run with
2917 * 		the pointer for start of data pointing to byte number *bytes*
2918 * 		**+ 1**. If *bytes* is larger than the current data being
2919 * 		processed, then the eBPF verdict will be applied to multiple
2920 * 		**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
2921 * 		consumed.
2922 *
2923 * 		Note that if a socket closes with the internal counter holding
2924 * 		a non-zero value, this is not a problem because data is not
2925 * 		being buffered for *bytes* and is sent as it is received.
2926 * 	Return
2927 * 		0
2928 *
2929 * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2930 * 	Description
2931 * 		For socket policies, prevent the execution of the verdict eBPF
2932 * 		program for message *msg* until *bytes* (byte number) have been
2933 * 		accumulated.
2934 *
2935 * 		This can be used when one needs a specific number of bytes
2936 * 		before a verdict can be assigned, even if the data spans
2937 * 		multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
2938 * 		case would be a user calling **sendmsg**\ () repeatedly with
2939 * 		1-byte long message segments. Obviously, this is bad for
2940 * 		performance, but it is still valid. If the eBPF program needs
2941 * 		*bytes* bytes to validate a header, this helper can be used to
2942 * 		prevent the eBPF program to be called again until *bytes* have
2943 * 		been accumulated.
2944 * 	Return
2945 * 		0
2946 *
2947 * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2948 * 	Description
2949 * 		For socket policies, pull in non-linear data from user space
2950 * 		for *msg* and set pointers *msg*\ **->data** and *msg*\
2951 * 		**->data_end** to *start* and *end* bytes offsets into *msg*,
2952 * 		respectively.
2953 *
2954 * 		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2955 * 		*msg* it can only parse data that the (**data**, **data_end**)
2956 * 		pointers have already consumed. For **sendmsg**\ () hooks this
2957 * 		is likely the first scatterlist element. But for calls relying
2958 * 		on the **sendpage** handler (e.g. **sendfile**\ ()) this will
2959 * 		be the range (**0**, **0**) because the data is shared with
2960 * 		user space and by default the objective is to avoid allowing
2961 * 		user space to modify data while (or after) eBPF verdict is
2962 * 		being decided. This helper can be used to pull in data and to
2963 * 		set the start and end pointer to given values. Data will be
2964 * 		copied if necessary (i.e. if data was not linear and if start
2965 * 		and end pointers do not point to the same chunk).
2966 *
2967 * 		A call to this helper is susceptible to change the underlying
2968 * 		packet buffer. Therefore, at load time, all checks on pointers
2969 * 		previously done by the verifier are invalidated and must be
2970 * 		performed again, if the helper is used in combination with
2971 * 		direct packet access.
2972 *
2973 * 		All values for *flags* are reserved for future usage, and must
2974 * 		be left at zero.
2975 * 	Return
2976 * 		0 on success, or a negative error in case of failure.
2977 *
2978 * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
2979 * 	Description
2980 * 		Bind the socket associated to *ctx* to the address pointed by
2981 * 		*addr*, of length *addr_len*. This allows for making outgoing
2982 * 		connection from the desired IP address, which can be useful for
2983 * 		example when all processes inside a cgroup should use one
2984 * 		single IP address on a host that has multiple IP configured.
2985 *
2986 * 		This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2987 * 		domain (*addr*\ **->sa_family**) must be **AF_INET** (or
2988 * 		**AF_INET6**). It's advised to pass zero port (**sin_port**
2989 * 		or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
2990 * 		behavior and lets the kernel efficiently pick up an unused
2991 * 		port as long as 4-tuple is unique. Passing non-zero port might
2992 * 		lead to degraded performance.
2993 * 	Return
2994 * 		0 on success, or a negative error in case of failure.
2995 *
2996 * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2997 * 	Description
2998 * 		Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
2999 * 		possible to both shrink and grow the packet tail.
3000 * 		Shrink done via *delta* being a negative integer.
3001 *
3002 * 		A call to this helper is susceptible to change the underlying
3003 * 		packet buffer. Therefore, at load time, all checks on pointers
3004 * 		previously done by the verifier are invalidated and must be
3005 * 		performed again, if the helper is used in combination with
3006 * 		direct packet access.
3007 * 	Return
3008 * 		0 on success, or a negative error in case of failure.
3009 *
3010 * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
3011 * 	Description
3012 * 		Retrieve the XFRM state (IP transform framework, see also
3013 * 		**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
3014 *
3015 * 		The retrieved value is stored in the **struct bpf_xfrm_state**
3016 * 		pointed by *xfrm_state* and of length *size*.
3017 *
3018 * 		All values for *flags* are reserved for future usage, and must
3019 * 		be left at zero.
3020 *
3021 * 		This helper is available only if the kernel was compiled with
3022 * 		**CONFIG_XFRM** configuration option.
3023 * 	Return
3024 * 		0 on success, or a negative error in case of failure.
3025 *
3026 * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
3027 * 	Description
3028 * 		Return a user or a kernel stack in bpf program provided buffer.
3029 * 		To achieve this, the helper needs *ctx*, which is a pointer
3030 * 		to the context on which the tracing program is executed.
3031 * 		To store the stacktrace, the bpf program provides *buf* with
3032 * 		a nonnegative *size*.
3033 *
3034 * 		The last argument, *flags*, holds the number of stack frames to
3035 * 		skip (from 0 to 255), masked with
3036 * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
3037 * 		the following flags:
3038 *
3039 * 		**BPF_F_USER_STACK**
3040 * 			Collect a user space stack instead of a kernel stack.
3041 * 		**BPF_F_USER_BUILD_ID**
3042 * 			Collect (build_id, file_offset) instead of ips for user
3043 * 			stack, only valid if **BPF_F_USER_STACK** is also
3044 * 			specified.
3045 *
3046 * 			*file_offset* is an offset relative to the beginning
3047 * 			of the executable or shared object file backing the vma
3048 * 			which the *ip* falls in. It is *not* an offset relative
3049 * 			to that object's base address. Accordingly, it must be
3050 * 			adjusted by adding (sh_addr - sh_offset), where
3051 * 			sh_{addr,offset} correspond to the executable section
3052 * 			containing *file_offset* in the object, for comparisons
3053 * 			to symbols' st_value to be valid.
3054 *
3055 * 		**bpf_get_stack**\ () can collect up to
3056 * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
3057 * 		to sufficient large buffer size. Note that
3058 * 		this limit can be controlled with the **sysctl** program, and
3059 * 		that it should be manually increased in order to profile long
3060 * 		user stacks (such as stacks for Java programs). To do so, use:
3061 *
3062 * 		::
3063 *
3064 * 			# sysctl kernel.perf_event_max_stack=<new value>
3065 * 	Return
3066 * 		The non-negative copied *buf* length equal to or less than
3067 * 		*size* on success, or a negative error in case of failure.
3068 *
3069 * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
3070 * 	Description
3071 * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
3072 * 		it provides an easy way to load *len* bytes from *offset*
3073 * 		from the packet associated to *skb*, into the buffer pointed
3074 * 		by *to*. The difference to **bpf_skb_load_bytes**\ () is that
3075 * 		a fifth argument *start_header* exists in order to select a
3076 * 		base offset to start from. *start_header* can be one of:
3077 *
3078 * 		**BPF_HDR_START_MAC**
3079 * 			Base offset to load data from is *skb*'s mac header.
3080 * 		**BPF_HDR_START_NET**
3081 * 			Base offset to load data from is *skb*'s network header.
3082 *
3083 * 		In general, "direct packet access" is the preferred method to
3084 * 		access packet data, however, this helper is in particular useful
3085 * 		in socket filters where *skb*\ **->data** does not always point
3086 * 		to the start of the mac header and where "direct packet access"
3087 * 		is not available.
3088 * 	Return
3089 * 		0 on success, or a negative error in case of failure.
3090 *
3091 * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
3092 *	Description
3093 *		Do FIB lookup in kernel tables using parameters in *params*.
3094 *		If lookup is successful and result shows packet is to be
3095 *		forwarded, the neighbor tables are searched for the nexthop.
3096 *		If successful (ie., FIB lookup shows forwarding and nexthop
3097 *		is resolved), the nexthop address is returned in ipv4_dst
3098 *		or ipv6_dst based on family, smac is set to mac address of
3099 *		egress device, dmac is set to nexthop mac address, rt_metric
3100 *		is set to metric from route (IPv4/IPv6 only), and ifindex
3101 *		is set to the device index of the nexthop from the FIB lookup.
3102 *
3103 *		*plen* argument is the size of the passed in struct.
3104 *		*flags* argument can be a combination of one or more of the
3105 *		following values:
3106 *
3107 *		**BPF_FIB_LOOKUP_DIRECT**
3108 *			Do a direct table lookup vs full lookup using FIB
3109 *			rules.
3110 *		**BPF_FIB_LOOKUP_OUTPUT**
3111 *			Perform lookup from an egress perspective (default is
3112 *			ingress).
3113 *
3114 *		*ctx* is either **struct xdp_md** for XDP programs or
3115 *		**struct sk_buff** tc cls_act programs.
3116 *	Return
3117 *		* < 0 if any input argument is invalid
3118 *		*   0 on success (packet is forwarded, nexthop neighbor exists)
3119 *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
3120 *		  packet is not forwarded or needs assist from full stack
3121 *
3122 *		If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3123 *		was exceeded and output params->mtu_result contains the MTU.
3124 *
3125 * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
3126 *	Description
3127 *		Add an entry to, or update a sockhash *map* referencing sockets.
3128 *		The *skops* is used as a new value for the entry associated to
3129 *		*key*. *flags* is one of:
3130 *
3131 *		**BPF_NOEXIST**
3132 *			The entry for *key* must not exist in the map.
3133 *		**BPF_EXIST**
3134 *			The entry for *key* must already exist in the map.
3135 *		**BPF_ANY**
3136 *			No condition on the existence of the entry for *key*.
3137 *
3138 *		If the *map* has eBPF programs (parser and verdict), those will
3139 *		be inherited by the socket being added. If the socket is
3140 *		already attached to eBPF programs, this results in an error.
3141 *	Return
3142 *		0 on success, or a negative error in case of failure.
3143 *
3144 * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
3145 *	Description
3146 *		This helper is used in programs implementing policies at the
3147 *		socket level. If the message *msg* is allowed to pass (i.e. if
3148 *		the verdict eBPF program returns **SK_PASS**), redirect it to
3149 *		the socket referenced by *map* (of type
3150 *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3151 *		egress interfaces can be used for redirection. The
3152 *		**BPF_F_INGRESS** value in *flags* is used to make the
3153 *		distinction (ingress path is selected if the flag is present,
3154 *		egress path otherwise). This is the only flag supported for now.
3155 *	Return
3156 *		**SK_PASS** on success, or **SK_DROP** on error.
3157 *
3158 * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
3159 *	Description
3160 *		This helper is used in programs implementing policies at the
3161 *		skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
3162 *		if the verdict eBPF program returns **SK_PASS**), redirect it
3163 *		to the socket referenced by *map* (of type
3164 *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3165 *		egress interfaces can be used for redirection. The
3166 *		**BPF_F_INGRESS** value in *flags* is used to make the
3167 *		distinction (ingress path is selected if the flag is present,
3168 *		egress otherwise). This is the only flag supported for now.
3169 *	Return
3170 *		**SK_PASS** on success, or **SK_DROP** on error.
3171 *
3172 * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
3173 *	Description
3174 *		Encapsulate the packet associated to *skb* within a Layer 3
3175 *		protocol header. This header is provided in the buffer at
3176 *		address *hdr*, with *len* its size in bytes. *type* indicates
3177 *		the protocol of the header and can be one of:
3178 *
3179 *		**BPF_LWT_ENCAP_SEG6**
3180 *			IPv6 encapsulation with Segment Routing Header
3181 *			(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
3182 *			the IPv6 header is computed by the kernel.
3183 *		**BPF_LWT_ENCAP_SEG6_INLINE**
3184 *			Only works if *skb* contains an IPv6 packet. Insert a
3185 *			Segment Routing Header (**struct ipv6_sr_hdr**) inside
3186 *			the IPv6 header.
3187 *		**BPF_LWT_ENCAP_IP**
3188 *			IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3189 *			must be IPv4 or IPv6, followed by zero or more
3190 *			additional headers, up to **LWT_BPF_MAX_HEADROOM**
3191 *			total bytes in all prepended headers. Please note that
3192 *			if **skb_is_gso**\ (*skb*) is true, no more than two
3193 *			headers can be prepended, and the inner header, if
3194 *			present, should be either GRE or UDP/GUE.
3195 *
3196 *		**BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
3197 *		of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
3198 *		be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
3199 *		**BPF_PROG_TYPE_LWT_XMIT**.
3200 *
3201 * 		A call to this helper is susceptible to change the underlying
3202 * 		packet buffer. Therefore, at load time, all checks on pointers
3203 * 		previously done by the verifier are invalidated and must be
3204 * 		performed again, if the helper is used in combination with
3205 * 		direct packet access.
3206 *	Return
3207 * 		0 on success, or a negative error in case of failure.
3208 *
3209 * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
3210 *	Description
3211 *		Store *len* bytes from address *from* into the packet
3212 *		associated to *skb*, at *offset*. Only the flags, tag and TLVs
3213 *		inside the outermost IPv6 Segment Routing Header can be
3214 *		modified through this helper.
3215 *
3216 * 		A call to this helper is susceptible to change the underlying
3217 * 		packet buffer. Therefore, at load time, all checks on pointers
3218 * 		previously done by the verifier are invalidated and must be
3219 * 		performed again, if the helper is used in combination with
3220 * 		direct packet access.
3221 *	Return
3222 * 		0 on success, or a negative error in case of failure.
3223 *
3224 * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3225 *	Description
3226 *		Adjust the size allocated to TLVs in the outermost IPv6
3227 *		Segment Routing Header contained in the packet associated to
3228 *		*skb*, at position *offset* by *delta* bytes. Only offsets
3229 *		after the segments are accepted. *delta* can be as well
3230 *		positive (growing) as negative (shrinking).
3231 *
3232 * 		A call to this helper is susceptible to change the underlying
3233 * 		packet buffer. Therefore, at load time, all checks on pointers
3234 * 		previously done by the verifier are invalidated and must be
3235 * 		performed again, if the helper is used in combination with
3236 * 		direct packet access.
3237 *	Return
3238 * 		0 on success, or a negative error in case of failure.
3239 *
3240 * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
3241 *	Description
3242 *		Apply an IPv6 Segment Routing action of type *action* to the
3243 *		packet associated to *skb*. Each action takes a parameter
3244 *		contained at address *param*, and of length *param_len* bytes.
3245 *		*action* can be one of:
3246 *
3247 *		**SEG6_LOCAL_ACTION_END_X**
3248 *			End.X action: Endpoint with Layer-3 cross-connect.
3249 *			Type of *param*: **struct in6_addr**.
3250 *		**SEG6_LOCAL_ACTION_END_T**
3251 *			End.T action: Endpoint with specific IPv6 table lookup.
3252 *			Type of *param*: **int**.
3253 *		**SEG6_LOCAL_ACTION_END_B6**
3254 *			End.B6 action: Endpoint bound to an SRv6 policy.
3255 *			Type of *param*: **struct ipv6_sr_hdr**.
3256 *		**SEG6_LOCAL_ACTION_END_B6_ENCAP**
3257 *			End.B6.Encap action: Endpoint bound to an SRv6
3258 *			encapsulation policy.
3259 *			Type of *param*: **struct ipv6_sr_hdr**.
3260 *
3261 * 		A call to this helper is susceptible to change the underlying
3262 * 		packet buffer. Therefore, at load time, all checks on pointers
3263 * 		previously done by the verifier are invalidated and must be
3264 * 		performed again, if the helper is used in combination with
3265 * 		direct packet access.
3266 *	Return
3267 * 		0 on success, or a negative error in case of failure.
3268 *
3269 * long bpf_rc_repeat(void *ctx)
3270 *	Description
3271 *		This helper is used in programs implementing IR decoding, to
3272 *		report a successfully decoded repeat key message. This delays
3273 *		the generation of a key up event for previously generated
3274 *		key down event.
3275 *
3276 *		Some IR protocols like NEC have a special IR message for
3277 *		repeating last button, for when a button is held down.
3278 *
3279 *		The *ctx* should point to the lirc sample as passed into
3280 *		the program.
3281 *
3282 *		This helper is only available is the kernel was compiled with
3283 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3284 *		"**y**".
3285 *	Return
3286 *		0
3287 *
3288 * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3289 *	Description
3290 *		This helper is used in programs implementing IR decoding, to
3291 *		report a successfully decoded key press with *scancode*,
3292 *		*toggle* value in the given *protocol*. The scancode will be
3293 *		translated to a keycode using the rc keymap, and reported as
3294 *		an input key down event. After a period a key up event is
3295 *		generated. This period can be extended by calling either
3296 *		**bpf_rc_keydown**\ () again with the same values, or calling
3297 *		**bpf_rc_repeat**\ ().
3298 *
3299 *		Some protocols include a toggle bit, in case the button was
3300 *		released and pressed again between consecutive scancodes.
3301 *
3302 *		The *ctx* should point to the lirc sample as passed into
3303 *		the program.
3304 *
3305 *		The *protocol* is the decoded protocol number (see
3306 *		**enum rc_proto** for some predefined values).
3307 *
3308 *		This helper is only available is the kernel was compiled with
3309 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3310 *		"**y**".
3311 *	Return
3312 *		0
3313 *
3314 * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3315 * 	Description
3316 * 		Return the cgroup v2 id of the socket associated with the *skb*.
3317 * 		This is roughly similar to the **bpf_get_cgroup_classid**\ ()
3318 * 		helper for cgroup v1 by providing a tag resp. identifier that
3319 * 		can be matched on or used for map lookups e.g. to implement
3320 * 		policy. The cgroup v2 id of a given path in the hierarchy is
3321 * 		exposed in user space through the f_handle API in order to get
3322 * 		to the same 64-bit id.
3323 *
3324 * 		This helper can be used on TC egress path, but not on ingress,
3325 * 		and is available only if the kernel was compiled with the
3326 * 		**CONFIG_SOCK_CGROUP_DATA** configuration option.
3327 * 	Return
3328 * 		The id is returned or 0 in case the id could not be retrieved.
3329 *
3330 * u64 bpf_get_current_cgroup_id(void)
3331 * 	Description
3332 * 		Get the current cgroup id based on the cgroup within which
3333 * 		the current task is running.
3334 * 	Return
3335 * 		A 64-bit integer containing the current cgroup id based
3336 * 		on the cgroup within which the current task is running.
3337 *
3338 * void *bpf_get_local_storage(void *map, u64 flags)
3339 *	Description
3340 *		Get the pointer to the local storage area.
3341 *		The type and the size of the local storage is defined
3342 *		by the *map* argument.
3343 *		The *flags* meaning is specific for each map type,
3344 *		and has to be 0 for cgroup local storage.
3345 *
3346 *		Depending on the BPF program type, a local storage area
3347 *		can be shared between multiple instances of the BPF program,
3348 *		running simultaneously.
3349 *
3350 *		A user should care about the synchronization by himself.
3351 *		For example, by using the **BPF_ATOMIC** instructions to alter
3352 *		the shared data.
3353 *	Return
3354 *		A pointer to the local storage area.
3355 *
3356 * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
3357 *	Description
3358 *		Select a **SO_REUSEPORT** socket from a
3359 *		**BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
3360 *		It checks the selected socket is matching the incoming
3361 *		request in the socket buffer.
3362 *	Return
3363 *		0 on success, or a negative error in case of failure.
3364 *
3365 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3366 *	Description
3367 *		Return id of cgroup v2 that is ancestor of cgroup associated
3368 *		with the *skb* at the *ancestor_level*.  The root cgroup is at
3369 *		*ancestor_level* zero and each step down the hierarchy
3370 *		increments the level. If *ancestor_level* == level of cgroup
3371 *		associated with *skb*, then return value will be same as that
3372 *		of **bpf_skb_cgroup_id**\ ().
3373 *
3374 *		The helper is useful to implement policies based on cgroups
3375 *		that are upper in hierarchy than immediate cgroup associated
3376 *		with *skb*.
3377 *
3378 *		The format of returned id and helper limitations are same as in
3379 *		**bpf_skb_cgroup_id**\ ().
3380 *	Return
3381 *		The id is returned or 0 in case the id could not be retrieved.
3382 *
3383 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3384 *	Description
3385 *		Look for TCP socket matching *tuple*, optionally in a child
3386 *		network namespace *netns*. The return value must be checked,
3387 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3388 *
3389 *		The *ctx* should point to the context of the program, such as
3390 *		the skb or socket (depending on the hook in use). This is used
3391 *		to determine the base network namespace for the lookup.
3392 *
3393 *		*tuple_size* must be one of:
3394 *
3395 *		**sizeof**\ (*tuple*\ **->ipv4**)
3396 *			Look for an IPv4 socket.
3397 *		**sizeof**\ (*tuple*\ **->ipv6**)
3398 *			Look for an IPv6 socket.
3399 *
3400 *		If the *netns* is a negative signed 32-bit integer, then the
3401 *		socket lookup table in the netns associated with the *ctx*
3402 *		will be used. For the TC hooks, this is the netns of the device
3403 *		in the skb. For socket hooks, this is the netns of the socket.
3404 *		If *netns* is any other signed 32-bit value greater than or
3405 *		equal to zero then it specifies the ID of the netns relative to
3406 *		the netns associated with the *ctx*. *netns* values beyond the
3407 *		range of 32-bit integers are reserved for future use.
3408 *
3409 *		All values for *flags* are reserved for future usage, and must
3410 *		be left at zero.
3411 *
3412 *		This helper is available only if the kernel was compiled with
3413 *		**CONFIG_NET** configuration option.
3414 *	Return
3415 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3416 *		For sockets with reuseport option, the **struct bpf_sock**
3417 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3418 *		tuple.
3419 *
3420 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3421 *	Description
3422 *		Look for UDP socket matching *tuple*, optionally in a child
3423 *		network namespace *netns*. The return value must be checked,
3424 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3425 *
3426 *		The *ctx* should point to the context of the program, such as
3427 *		the skb or socket (depending on the hook in use). This is used
3428 *		to determine the base network namespace for the lookup.
3429 *
3430 *		*tuple_size* must be one of:
3431 *
3432 *		**sizeof**\ (*tuple*\ **->ipv4**)
3433 *			Look for an IPv4 socket.
3434 *		**sizeof**\ (*tuple*\ **->ipv6**)
3435 *			Look for an IPv6 socket.
3436 *
3437 *		If the *netns* is a negative signed 32-bit integer, then the
3438 *		socket lookup table in the netns associated with the *ctx*
3439 *		will be used. For the TC hooks, this is the netns of the device
3440 *		in the skb. For socket hooks, this is the netns of the socket.
3441 *		If *netns* is any other signed 32-bit value greater than or
3442 *		equal to zero then it specifies the ID of the netns relative to
3443 *		the netns associated with the *ctx*. *netns* values beyond the
3444 *		range of 32-bit integers are reserved for future use.
3445 *
3446 *		All values for *flags* are reserved for future usage, and must
3447 *		be left at zero.
3448 *
3449 *		This helper is available only if the kernel was compiled with
3450 *		**CONFIG_NET** configuration option.
3451 *	Return
3452 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3453 *		For sockets with reuseport option, the **struct bpf_sock**
3454 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3455 *		tuple.
3456 *
3457 * long bpf_sk_release(void *sock)
3458 *	Description
3459 *		Release the reference held by *sock*. *sock* must be a
3460 *		non-**NULL** pointer that was returned from
3461 *		**bpf_sk_lookup_xxx**\ ().
3462 *	Return
3463 *		0 on success, or a negative error in case of failure.
3464 *
3465 * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
3466 * 	Description
3467 * 		Push an element *value* in *map*. *flags* is one of:
3468 *
3469 * 		**BPF_EXIST**
3470 * 			If the queue/stack is full, the oldest element is
3471 * 			removed to make room for this.
3472 * 	Return
3473 * 		0 on success, or a negative error in case of failure.
3474 *
3475 * long bpf_map_pop_elem(struct bpf_map *map, void *value)
3476 * 	Description
3477 * 		Pop an element from *map*.
3478 * 	Return
3479 * 		0 on success, or a negative error in case of failure.
3480 *
3481 * long bpf_map_peek_elem(struct bpf_map *map, void *value)
3482 * 	Description
3483 * 		Get an element from *map* without removing it.
3484 * 	Return
3485 * 		0 on success, or a negative error in case of failure.
3486 *
3487 * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3488 *	Description
3489 *		For socket policies, insert *len* bytes into *msg* at offset
3490 *		*start*.
3491 *
3492 *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
3493 *		*msg* it may want to insert metadata or options into the *msg*.
3494 *		This can later be read and used by any of the lower layer BPF
3495 *		hooks.
3496 *
3497 *		This helper may fail if under memory pressure (a malloc
3498 *		fails) in these cases BPF programs will get an appropriate
3499 *		error and BPF programs will need to handle them.
3500 *	Return
3501 *		0 on success, or a negative error in case of failure.
3502 *
3503 * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3504 *	Description
3505 *		Will remove *len* bytes from a *msg* starting at byte *start*.
3506 *		This may result in **ENOMEM** errors under certain situations if
3507 *		an allocation and copy are required due to a full ring buffer.
3508 *		However, the helper will try to avoid doing the allocation
3509 *		if possible. Other errors can occur if input parameters are
3510 *		invalid either due to *start* byte not being valid part of *msg*
3511 *		payload and/or *pop* value being to large.
3512 *	Return
3513 *		0 on success, or a negative error in case of failure.
3514 *
3515 * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3516 *	Description
3517 *		This helper is used in programs implementing IR decoding, to
3518 *		report a successfully decoded pointer movement.
3519 *
3520 *		The *ctx* should point to the lirc sample as passed into
3521 *		the program.
3522 *
3523 *		This helper is only available is the kernel was compiled with
3524 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3525 *		"**y**".
3526 *	Return
3527 *		0
3528 *
3529 * long bpf_spin_lock(struct bpf_spin_lock *lock)
3530 *	Description
3531 *		Acquire a spinlock represented by the pointer *lock*, which is
3532 *		stored as part of a value of a map. Taking the lock allows to
3533 *		safely update the rest of the fields in that value. The
3534 *		spinlock can (and must) later be released with a call to
3535 *		**bpf_spin_unlock**\ (\ *lock*\ ).
3536 *
3537 *		Spinlocks in BPF programs come with a number of restrictions
3538 *		and constraints:
3539 *
3540 *		* **bpf_spin_lock** objects are only allowed inside maps of
3541 *		  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
3542 *		  list could be extended in the future).
3543 *		* BTF description of the map is mandatory.
3544 *		* The BPF program can take ONE lock at a time, since taking two
3545 *		  or more could cause dead locks.
3546 *		* Only one **struct bpf_spin_lock** is allowed per map element.
3547 *		* When the lock is taken, calls (either BPF to BPF or helpers)
3548 *		  are not allowed.
3549 *		* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
3550 *		  allowed inside a spinlock-ed region.
3551 *		* The BPF program MUST call **bpf_spin_unlock**\ () to release
3552 *		  the lock, on all execution paths, before it returns.
3553 *		* The BPF program can access **struct bpf_spin_lock** only via
3554 *		  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
3555 *		  helpers. Loading or storing data into the **struct
3556 *		  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
3557 *		* To use the **bpf_spin_lock**\ () helper, the BTF description
3558 *		  of the map value must be a struct and have **struct
3559 *		  bpf_spin_lock** *anyname*\ **;** field at the top level.
3560 *		  Nested lock inside another struct is not allowed.
3561 *		* The **struct bpf_spin_lock** *lock* field in a map value must
3562 *		  be aligned on a multiple of 4 bytes in that value.
3563 *		* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
3564 *		  the **bpf_spin_lock** field to user space.
3565 *		* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
3566 *		  a BPF program, do not update the **bpf_spin_lock** field.
3567 *		* **bpf_spin_lock** cannot be on the stack or inside a
3568 *		  networking packet (it can only be inside of a map values).
3569 *		* **bpf_spin_lock** is available to root only.
3570 *		* Tracing programs and socket filter programs cannot use
3571 *		  **bpf_spin_lock**\ () due to insufficient preemption checks
3572 *		  (but this may change in the future).
3573 *		* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
3574 *	Return
3575 *		0
3576 *
3577 * long bpf_spin_unlock(struct bpf_spin_lock *lock)
3578 *	Description
3579 *		Release the *lock* previously locked by a call to
3580 *		**bpf_spin_lock**\ (\ *lock*\ ).
3581 *	Return
3582 *		0
3583 *
3584 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
3585 *	Description
3586 *		This helper gets a **struct bpf_sock** pointer such
3587 *		that all the fields in this **bpf_sock** can be accessed.
3588 *	Return
3589 *		A **struct bpf_sock** pointer on success, or **NULL** in
3590 *		case of failure.
3591 *
3592 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
3593 *	Description
3594 *		This helper gets a **struct bpf_tcp_sock** pointer from a
3595 *		**struct bpf_sock** pointer.
3596 *	Return
3597 *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
3598 *		case of failure.
3599 *
3600 * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3601 *	Description
3602 *		Set ECN (Explicit Congestion Notification) field of IP header
3603 *		to **CE** (Congestion Encountered) if current value is **ECT**
3604 *		(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3605 *		and IPv4.
3606 *	Return
3607 *		1 if the **CE** flag is set (either by the current helper call
3608 *		or because it was already present), 0 if it is not set.
3609 *
3610 * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
3611 *	Description
3612 *		Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
3613 *		**bpf_sk_release**\ () is unnecessary and not allowed.
3614 *	Return
3615 *		A **struct bpf_sock** pointer on success, or **NULL** in
3616 *		case of failure.
3617 *
3618 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3619 *	Description
3620 *		Look for TCP socket matching *tuple*, optionally in a child
3621 *		network namespace *netns*. The return value must be checked,
3622 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3623 *
3624 *		This function is identical to **bpf_sk_lookup_tcp**\ (), except
3625 *		that it also returns timewait or request sockets. Use
3626 *		**bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
3627 *		full structure.
3628 *
3629 *		This helper is available only if the kernel was compiled with
3630 *		**CONFIG_NET** configuration option.
3631 *	Return
3632 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3633 *		For sockets with reuseport option, the **struct bpf_sock**
3634 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3635 *		tuple.
3636 *
3637 * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3638 * 	Description
3639 * 		Check whether *iph* and *th* contain a valid SYN cookie ACK for
3640 * 		the listening socket in *sk*.
3641 *
3642 * 		*iph* points to the start of the IPv4 or IPv6 header, while
3643 * 		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3644 * 		**sizeof**\ (**struct ipv6hdr**).
3645 *
3646 * 		*th* points to the start of the TCP header, while *th_len*
3647 *		contains the length of the TCP header (at least
3648 *		**sizeof**\ (**struct tcphdr**)).
3649 * 	Return
3650 * 		0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
3651 * 		error otherwise.
3652 *
3653 * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
3654 *	Description
3655 *		Get name of sysctl in /proc/sys/ and copy it into provided by
3656 *		program buffer *buf* of size *buf_len*.
3657 *
3658 *		The buffer is always NUL terminated, unless it's zero-sized.
3659 *
3660 *		If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
3661 *		copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
3662 *		only (e.g. "tcp_mem").
3663 *	Return
3664 *		Number of character copied (not including the trailing NUL).
3665 *
3666 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3667 *		truncated name in this case).
3668 *
3669 * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3670 *	Description
3671 *		Get current value of sysctl as it is presented in /proc/sys
3672 *		(incl. newline, etc), and copy it as a string into provided
3673 *		by program buffer *buf* of size *buf_len*.
3674 *
3675 *		The whole value is copied, no matter what file position user
3676 *		space issued e.g. sys_read at.
3677 *
3678 *		The buffer is always NUL terminated, unless it's zero-sized.
3679 *	Return
3680 *		Number of character copied (not including the trailing NUL).
3681 *
3682 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3683 *		truncated name in this case).
3684 *
3685 *		**-EINVAL** if current value was unavailable, e.g. because
3686 *		sysctl is uninitialized and read returns -EIO for it.
3687 *
3688 * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3689 *	Description
3690 *		Get new value being written by user space to sysctl (before
3691 *		the actual write happens) and copy it as a string into
3692 *		provided by program buffer *buf* of size *buf_len*.
3693 *
3694 *		User space may write new value at file position > 0.
3695 *
3696 *		The buffer is always NUL terminated, unless it's zero-sized.
3697 *	Return
3698 *		Number of character copied (not including the trailing NUL).
3699 *
3700 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3701 *		truncated name in this case).
3702 *
3703 *		**-EINVAL** if sysctl is being read.
3704 *
3705 * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
3706 *	Description
3707 *		Override new value being written by user space to sysctl with
3708 *		value provided by program in buffer *buf* of size *buf_len*.
3709 *
3710 *		*buf* should contain a string in same form as provided by user
3711 *		space on sysctl write.
3712 *
3713 *		User space may write new value at file position > 0. To override
3714 *		the whole sysctl value file position should be set to zero.
3715 *	Return
3716 *		0 on success.
3717 *
3718 *		**-E2BIG** if the *buf_len* is too big.
3719 *
3720 *		**-EINVAL** if sysctl is being read.
3721 *
3722 * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
3723 *	Description
3724 *		Convert the initial part of the string from buffer *buf* of
3725 *		size *buf_len* to a long integer according to the given base
3726 *		and save the result in *res*.
3727 *
3728 *		The string may begin with an arbitrary amount of white space
3729 *		(as determined by **isspace**\ (3)) followed by a single
3730 *		optional '**-**' sign.
3731 *
3732 *		Five least significant bits of *flags* encode base, other bits
3733 *		are currently unused.
3734 *
3735 *		Base must be either 8, 10, 16 or 0 to detect it automatically
3736 *		similar to user space **strtol**\ (3).
3737 *	Return
3738 *		Number of characters consumed on success. Must be positive but
3739 *		no more than *buf_len*.
3740 *
3741 *		**-EINVAL** if no valid digits were found or unsupported base
3742 *		was provided.
3743 *
3744 *		**-ERANGE** if resulting value was out of range.
3745 *
3746 * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
3747 *	Description
3748 *		Convert the initial part of the string from buffer *buf* of
3749 *		size *buf_len* to an unsigned long integer according to the
3750 *		given base and save the result in *res*.
3751 *
3752 *		The string may begin with an arbitrary amount of white space
3753 *		(as determined by **isspace**\ (3)).
3754 *
3755 *		Five least significant bits of *flags* encode base, other bits
3756 *		are currently unused.
3757 *
3758 *		Base must be either 8, 10, 16 or 0 to detect it automatically
3759 *		similar to user space **strtoul**\ (3).
3760 *	Return
3761 *		Number of characters consumed on success. Must be positive but
3762 *		no more than *buf_len*.
3763 *
3764 *		**-EINVAL** if no valid digits were found or unsupported base
3765 *		was provided.
3766 *
3767 *		**-ERANGE** if resulting value was out of range.
3768 *
3769 * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
3770 *	Description
3771 *		Get a bpf-local-storage from a *sk*.
3772 *
3773 *		Logically, it could be thought of getting the value from
3774 *		a *map* with *sk* as the **key**.  From this
3775 *		perspective,  the usage is not much different from
3776 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
3777 *		helper enforces the key must be a full socket and the map must
3778 *		be a **BPF_MAP_TYPE_SK_STORAGE** also.
3779 *
3780 *		Underneath, the value is stored locally at *sk* instead of
3781 *		the *map*.  The *map* is used as the bpf-local-storage
3782 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
3783 *		searched against all bpf-local-storages residing at *sk*.
3784 *
3785 *		*sk* is a kernel **struct sock** pointer for LSM program.
3786 *		*sk* is a **struct bpf_sock** pointer for other program types.
3787 *
3788 *		An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
3789 *		used such that a new bpf-local-storage will be
3790 *		created if one does not exist.  *value* can be used
3791 *		together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
3792 *		the initial value of a bpf-local-storage.  If *value* is
3793 *		**NULL**, the new bpf-local-storage will be zero initialized.
3794 *	Return
3795 *		A bpf-local-storage pointer is returned on success.
3796 *
3797 *		**NULL** if not found or there was an error in adding
3798 *		a new bpf-local-storage.
3799 *
3800 * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
3801 *	Description
3802 *		Delete a bpf-local-storage from a *sk*.
3803 *	Return
3804 *		0 on success.
3805 *
3806 *		**-ENOENT** if the bpf-local-storage cannot be found.
3807 *		**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
3808 *
3809 * long bpf_send_signal(u32 sig)
3810 *	Description
3811 *		Send signal *sig* to the process of the current task.
3812 *		The signal may be delivered to any of this process's threads.
3813 *	Return
3814 *		0 on success or successfully queued.
3815 *
3816 *		**-EBUSY** if work queue under nmi is full.
3817 *
3818 *		**-EINVAL** if *sig* is invalid.
3819 *
3820 *		**-EPERM** if no permission to send the *sig*.
3821 *
3822 *		**-EAGAIN** if bpf program can try again.
3823 *
3824 * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3825 *	Description
3826 *		Try to issue a SYN cookie for the packet with corresponding
3827 *		IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
3828 *
3829 *		*iph* points to the start of the IPv4 or IPv6 header, while
3830 *		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3831 *		**sizeof**\ (**struct ipv6hdr**).
3832 *
3833 *		*th* points to the start of the TCP header, while *th_len*
3834 *		contains the length of the TCP header with options (at least
3835 *		**sizeof**\ (**struct tcphdr**)).
3836 *	Return
3837 *		On success, lower 32 bits hold the generated SYN cookie in
3838 *		followed by 16 bits which hold the MSS value for that cookie,
3839 *		and the top 16 bits are unused.
3840 *
3841 *		On failure, the returned value is one of the following:
3842 *
3843 *		**-EINVAL** SYN cookie cannot be issued due to error
3844 *
3845 *		**-ENOENT** SYN cookie should not be issued (no SYN flood)
3846 *
3847 *		**-EOPNOTSUPP** kernel configuration does not enable SYN cookies
3848 *
3849 *		**-EPROTONOSUPPORT** IP packet version is not 4 or 6
3850 *
3851 * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3852 * 	Description
3853 * 		Write raw *data* blob into a special BPF perf event held by
3854 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3855 * 		event must have the following attributes: **PERF_SAMPLE_RAW**
3856 * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3857 * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3858 *
3859 * 		The *flags* are used to indicate the index in *map* for which
3860 * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
3861 * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3862 * 		to indicate that the index of the current CPU core should be
3863 * 		used.
3864 *
3865 * 		The value to write, of *size*, is passed through eBPF stack and
3866 * 		pointed by *data*.
3867 *
3868 * 		*ctx* is a pointer to in-kernel struct sk_buff.
3869 *
3870 * 		This helper is similar to **bpf_perf_event_output**\ () but
3871 * 		restricted to raw_tracepoint bpf programs.
3872 * 	Return
3873 * 		0 on success, or a negative error in case of failure.
3874 *
3875 * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
3876 * 	Description
3877 * 		Safely attempt to read *size* bytes from user space address
3878 * 		*unsafe_ptr* and store the data in *dst*.
3879 * 	Return
3880 * 		0 on success, or a negative error in case of failure.
3881 *
3882 * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
3883 * 	Description
3884 * 		Safely attempt to read *size* bytes from kernel space address
3885 * 		*unsafe_ptr* and store the data in *dst*.
3886 * 	Return
3887 * 		0 on success, or a negative error in case of failure.
3888 *
3889 * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
3890 * 	Description
3891 * 		Copy a NUL terminated string from an unsafe user address
3892 * 		*unsafe_ptr* to *dst*. The *size* should include the
3893 * 		terminating NUL byte. In case the string length is smaller than
3894 * 		*size*, the target is not padded with further NUL bytes. If the
3895 * 		string length is larger than *size*, just *size*-1 bytes are
3896 * 		copied and the last byte is set to NUL.
3897 *
3898 * 		On success, returns the number of bytes that were written,
3899 * 		including the terminal NUL. This makes this helper useful in
3900 * 		tracing programs for reading strings, and more importantly to
3901 * 		get its length at runtime. See the following snippet:
3902 *
3903 * 		::
3904 *
3905 * 			SEC("kprobe/sys_open")
3906 * 			void bpf_sys_open(struct pt_regs *ctx)
3907 * 			{
3908 * 			        char buf[PATHLEN]; // PATHLEN is defined to 256
3909 * 			        int res = bpf_probe_read_user_str(buf, sizeof(buf),
3910 * 				                                  ctx->di);
3911 *
3912 * 				// Consume buf, for example push it to
3913 * 				// userspace via bpf_perf_event_output(); we
3914 * 				// can use res (the string length) as event
3915 * 				// size, after checking its boundaries.
3916 * 			}
3917 *
3918 * 		In comparison, using **bpf_probe_read_user**\ () helper here
3919 * 		instead to read the string would require to estimate the length
3920 * 		at compile time, and would often result in copying more memory
3921 * 		than necessary.
3922 *
3923 * 		Another useful use case is when parsing individual process
3924 * 		arguments or individual environment variables navigating
3925 * 		*current*\ **->mm->arg_start** and *current*\
3926 * 		**->mm->env_start**: using this helper and the return value,
3927 * 		one can quickly iterate at the right offset of the memory area.
3928 * 	Return
3929 * 		On success, the strictly positive length of the output string,
3930 * 		including the trailing NUL character. On error, a negative
3931 * 		value.
3932 *
3933 * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
3934 * 	Description
3935 * 		Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
3936 * 		to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
3937 * 	Return
3938 * 		On success, the strictly positive length of the string, including
3939 * 		the trailing NUL character. On error, a negative value.
3940 *
3941 * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3942 *	Description
3943 *		Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
3944 *		*rcv_nxt* is the ack_seq to be sent out.
3945 *	Return
3946 *		0 on success, or a negative error in case of failure.
3947 *
3948 * long bpf_send_signal_thread(u32 sig)
3949 *	Description
3950 *		Send signal *sig* to the thread corresponding to the current task.
3951 *	Return
3952 *		0 on success or successfully queued.
3953 *
3954 *		**-EBUSY** if work queue under nmi is full.
3955 *
3956 *		**-EINVAL** if *sig* is invalid.
3957 *
3958 *		**-EPERM** if no permission to send the *sig*.
3959 *
3960 *		**-EAGAIN** if bpf program can try again.
3961 *
3962 * u64 bpf_jiffies64(void)
3963 *	Description
3964 *		Obtain the 64bit jiffies
3965 *	Return
3966 *		The 64 bit jiffies
3967 *
3968 * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
3969 *	Description
3970 *		For an eBPF program attached to a perf event, retrieve the
3971 *		branch records (**struct perf_branch_entry**) associated to *ctx*
3972 *		and store it in the buffer pointed by *buf* up to size
3973 *		*size* bytes.
3974 *	Return
3975 *		On success, number of bytes written to *buf*. On error, a
3976 *		negative value.
3977 *
3978 *		The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
3979 *		instead return the number of bytes required to store all the
3980 *		branch entries. If this flag is set, *buf* may be NULL.
3981 *
3982 *		**-EINVAL** if arguments invalid or **size** not a multiple
3983 *		of **sizeof**\ (**struct perf_branch_entry**\ ).
3984 *
3985 *		**-ENOENT** if architecture does not support branch records.
3986 *
3987 * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3988 *	Description
3989 *		Returns 0 on success, values for *pid* and *tgid* as seen from the current
3990 *		*namespace* will be returned in *nsdata*.
3991 *	Return
3992 *		0 on success, or one of the following in case of failure:
3993 *
3994 *		**-EINVAL** if dev and inum supplied don't match dev_t and inode number
3995 *              with nsfs of current task, or if dev conversion to dev_t lost high bits.
3996 *
3997 *		**-ENOENT** if pidns does not exists for the current task.
3998 *
3999 * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
4000 *	Description
4001 *		Write raw *data* blob into a special BPF perf event held by
4002 *		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
4003 *		event must have the following attributes: **PERF_SAMPLE_RAW**
4004 *		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
4005 *		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
4006 *
4007 *		The *flags* are used to indicate the index in *map* for which
4008 *		the value must be put, masked with **BPF_F_INDEX_MASK**.
4009 *		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
4010 *		to indicate that the index of the current CPU core should be
4011 *		used.
4012 *
4013 *		The value to write, of *size*, is passed through eBPF stack and
4014 *		pointed by *data*.
4015 *
4016 *		*ctx* is a pointer to in-kernel struct xdp_buff.
4017 *
4018 *		This helper is similar to **bpf_perf_eventoutput**\ () but
4019 *		restricted to raw_tracepoint bpf programs.
4020 *	Return
4021 *		0 on success, or a negative error in case of failure.
4022 *
4023 * u64 bpf_get_netns_cookie(void *ctx)
4024 * 	Description
4025 * 		Retrieve the cookie (generated by the kernel) of the network
4026 * 		namespace the input *ctx* is associated with. The network
4027 * 		namespace cookie remains stable for its lifetime and provides
4028 * 		a global identifier that can be assumed unique. If *ctx* is
4029 * 		NULL, then the helper returns the cookie for the initial
4030 * 		network namespace. The cookie itself is very similar to that
4031 * 		of **bpf_get_socket_cookie**\ () helper, but for network
4032 * 		namespaces instead of sockets.
4033 * 	Return
4034 * 		A 8-byte long opaque number.
4035 *
4036 * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
4037 * 	Description
4038 * 		Return id of cgroup v2 that is ancestor of the cgroup associated
4039 * 		with the current task at the *ancestor_level*. The root cgroup
4040 * 		is at *ancestor_level* zero and each step down the hierarchy
4041 * 		increments the level. If *ancestor_level* == level of cgroup
4042 * 		associated with the current task, then return value will be the
4043 * 		same as that of **bpf_get_current_cgroup_id**\ ().
4044 *
4045 * 		The helper is useful to implement policies based on cgroups
4046 * 		that are upper in hierarchy than immediate cgroup associated
4047 * 		with the current task.
4048 *
4049 * 		The format of returned id and helper limitations are same as in
4050 * 		**bpf_get_current_cgroup_id**\ ().
4051 * 	Return
4052 * 		The id is returned or 0 in case the id could not be retrieved.
4053 *
4054 * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
4055 *	Description
4056 *		Helper is overloaded depending on BPF program type. This
4057 *		description applies to **BPF_PROG_TYPE_SCHED_CLS** and
4058 *		**BPF_PROG_TYPE_SCHED_ACT** programs.
4059 *
4060 *		Assign the *sk* to the *skb*. When combined with appropriate
4061 *		routing configuration to receive the packet towards the socket,
4062 *		will cause *skb* to be delivered to the specified socket.
4063 *		Subsequent redirection of *skb* via  **bpf_redirect**\ (),
4064 *		**bpf_clone_redirect**\ () or other methods outside of BPF may
4065 *		interfere with successful delivery to the socket.
4066 *
4067 *		This operation is only valid from TC ingress path.
4068 *
4069 *		The *flags* argument must be zero.
4070 *	Return
4071 *		0 on success, or a negative error in case of failure:
4072 *
4073 *		**-EINVAL** if specified *flags* are not supported.
4074 *
4075 *		**-ENOENT** if the socket is unavailable for assignment.
4076 *
4077 *		**-ENETUNREACH** if the socket is unreachable (wrong netns).
4078 *
4079 *		**-EOPNOTSUPP** if the operation is not supported, for example
4080 *		a call from outside of TC ingress.
4081 *
4082 *		**-ESOCKTNOSUPPORT** if the socket type is not supported
4083 *		(reuseport).
4084 *
4085 * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
4086 *	Description
4087 *		Helper is overloaded depending on BPF program type. This
4088 *		description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
4089 *
4090 *		Select the *sk* as a result of a socket lookup.
4091 *
4092 *		For the operation to succeed passed socket must be compatible
4093 *		with the packet description provided by the *ctx* object.
4094 *
4095 *		L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
4096 *		be an exact match. While IP family (**AF_INET** or
4097 *		**AF_INET6**) must be compatible, that is IPv6 sockets
4098 *		that are not v6-only can be selected for IPv4 packets.
4099 *
4100 *		Only TCP listeners and UDP unconnected sockets can be
4101 *		selected. *sk* can also be NULL to reset any previous
4102 *		selection.
4103 *
4104 *		*flags* argument can combination of following values:
4105 *
4106 *		* **BPF_SK_LOOKUP_F_REPLACE** to override the previous
4107 *		  socket selection, potentially done by a BPF program
4108 *		  that ran before us.
4109 *
4110 *		* **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
4111 *		  load-balancing within reuseport group for the socket
4112 *		  being selected.
4113 *
4114 *		On success *ctx->sk* will point to the selected socket.
4115 *
4116 *	Return
4117 *		0 on success, or a negative errno in case of failure.
4118 *
4119 *		* **-EAFNOSUPPORT** if socket family (*sk->family*) is
4120 *		  not compatible with packet family (*ctx->family*).
4121 *
4122 *		* **-EEXIST** if socket has been already selected,
4123 *		  potentially by another program, and
4124 *		  **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
4125 *
4126 *		* **-EINVAL** if unsupported flags were specified.
4127 *
4128 *		* **-EPROTOTYPE** if socket L4 protocol
4129 *		  (*sk->protocol*) doesn't match packet protocol
4130 *		  (*ctx->protocol*).
4131 *
4132 *		* **-ESOCKTNOSUPPORT** if socket is not in allowed
4133 *		  state (TCP listening or UDP unconnected).
4134 *
4135 * u64 bpf_ktime_get_boot_ns(void)
4136 * 	Description
4137 * 		Return the time elapsed since system boot, in nanoseconds.
4138 * 		Does include the time the system was suspended.
4139 * 		See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
4140 * 	Return
4141 * 		Current *ktime*.
4142 *
4143 * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4144 * 	Description
4145 * 		**bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
4146 * 		out the format string.
4147 * 		The *m* represents the seq_file. The *fmt* and *fmt_size* are for
4148 * 		the format string itself. The *data* and *data_len* are format string
4149 * 		arguments. The *data* are a **u64** array and corresponding format string
4150 * 		values are stored in the array. For strings and pointers where pointees
4151 * 		are accessed, only the pointer values are stored in the *data* array.
4152 * 		The *data_len* is the size of *data* in bytes - must be a multiple of 8.
4153 *
4154 *		Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
4155 *		Reading kernel memory may fail due to either invalid address or
4156 *		valid address but requiring a major memory fault. If reading kernel memory
4157 *		fails, the string for **%s** will be an empty string, and the ip
4158 *		address for **%p{i,I}{4,6}** will be 0. Not returning error to
4159 *		bpf program is consistent with what **bpf_trace_printk**\ () does for now.
4160 * 	Return
4161 * 		0 on success, or a negative error in case of failure:
4162 *
4163 *		**-EBUSY** if per-CPU memory copy buffer is busy, can try again
4164 *		by returning 1 from bpf program.
4165 *
4166 *		**-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
4167 *
4168 *		**-E2BIG** if *fmt* contains too many format specifiers.
4169 *
4170 *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4171 *
4172 * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
4173 * 	Description
4174 * 		**bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
4175 * 		The *m* represents the seq_file. The *data* and *len* represent the
4176 * 		data to write in bytes.
4177 * 	Return
4178 * 		0 on success, or a negative error in case of failure:
4179 *
4180 *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4181 *
4182 * u64 bpf_sk_cgroup_id(void *sk)
4183 *	Description
4184 *		Return the cgroup v2 id of the socket *sk*.
4185 *
4186 *		*sk* must be a non-**NULL** pointer to a socket, e.g. one
4187 *		returned from **bpf_sk_lookup_xxx**\ (),
4188 *		**bpf_sk_fullsock**\ (), etc. The format of returned id is
4189 *		same as in **bpf_skb_cgroup_id**\ ().
4190 *
4191 *		This helper is available only if the kernel was compiled with
4192 *		the **CONFIG_SOCK_CGROUP_DATA** configuration option.
4193 *	Return
4194 *		The id is returned or 0 in case the id could not be retrieved.
4195 *
4196 * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4197 *	Description
4198 *		Return id of cgroup v2 that is ancestor of cgroup associated
4199 *		with the *sk* at the *ancestor_level*.  The root cgroup is at
4200 *		*ancestor_level* zero and each step down the hierarchy
4201 *		increments the level. If *ancestor_level* == level of cgroup
4202 *		associated with *sk*, then return value will be same as that
4203 *		of **bpf_sk_cgroup_id**\ ().
4204 *
4205 *		The helper is useful to implement policies based on cgroups
4206 *		that are upper in hierarchy than immediate cgroup associated
4207 *		with *sk*.
4208 *
4209 *		The format of returned id and helper limitations are same as in
4210 *		**bpf_sk_cgroup_id**\ ().
4211 *	Return
4212 *		The id is returned or 0 in case the id could not be retrieved.
4213 *
4214 * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
4215 * 	Description
4216 * 		Copy *size* bytes from *data* into a ring buffer *ringbuf*.
4217 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4218 * 		of new data availability is sent.
4219 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4220 * 		of new data availability is sent unconditionally.
4221 * 		If **0** is specified in *flags*, an adaptive notification
4222 * 		of new data availability is sent.
4223 *
4224 * 		An adaptive notification is a notification sent whenever the user-space
4225 * 		process has caught up and consumed all available payloads. In case the user-space
4226 * 		process is still processing a previous payload, then no notification is needed
4227 * 		as it will process the newly added payload automatically.
4228 * 	Return
4229 * 		0 on success, or a negative error in case of failure.
4230 *
4231 * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
4232 * 	Description
4233 * 		Reserve *size* bytes of payload in a ring buffer *ringbuf*.
4234 * 		*flags* must be 0.
4235 * 	Return
4236 * 		Valid pointer with *size* bytes of memory available; NULL,
4237 * 		otherwise.
4238 *
4239 * void bpf_ringbuf_submit(void *data, u64 flags)
4240 * 	Description
4241 * 		Submit reserved ring buffer sample, pointed to by *data*.
4242 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4243 * 		of new data availability is sent.
4244 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4245 * 		of new data availability is sent unconditionally.
4246 * 		If **0** is specified in *flags*, an adaptive notification
4247 * 		of new data availability is sent.
4248 *
4249 * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4250 * 	Return
4251 * 		Nothing. Always succeeds.
4252 *
4253 * void bpf_ringbuf_discard(void *data, u64 flags)
4254 * 	Description
4255 * 		Discard reserved ring buffer sample, pointed to by *data*.
4256 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4257 * 		of new data availability is sent.
4258 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4259 * 		of new data availability is sent unconditionally.
4260 * 		If **0** is specified in *flags*, an adaptive notification
4261 * 		of new data availability is sent.
4262 *
4263 * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4264 * 	Return
4265 * 		Nothing. Always succeeds.
4266 *
4267 * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4268 *	Description
4269 *		Query various characteristics of provided ring buffer. What
4270 *		exactly is queries is determined by *flags*:
4271 *
4272 *		* **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
4273 *		* **BPF_RB_RING_SIZE**: The size of ring buffer.
4274 *		* **BPF_RB_CONS_POS**: Consumer position (can wrap around).
4275 *		* **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
4276 *
4277 *		Data returned is just a momentary snapshot of actual values
4278 *		and could be inaccurate, so this facility should be used to
4279 *		power heuristics and for reporting, not to make 100% correct
4280 *		calculation.
4281 *	Return
4282 *		Requested value, or 0, if *flags* are not recognized.
4283 *
4284 * long bpf_csum_level(struct sk_buff *skb, u64 level)
4285 * 	Description
4286 * 		Change the skbs checksum level by one layer up or down, or
4287 * 		reset it entirely to none in order to have the stack perform
4288 * 		checksum validation. The level is applicable to the following
4289 * 		protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4290 * 		| ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
4291 * 		through **bpf_skb_adjust_room**\ () helper with passing in
4292 * 		**BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one	call
4293 * 		to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
4294 * 		the UDP header is removed. Similarly, an encap of the latter
4295 * 		into the former could be accompanied by a helper call to
4296 * 		**bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
4297 * 		skb is still intended to be processed in higher layers of the
4298 * 		stack instead of just egressing at tc.
4299 *
4300 * 		There are three supported level settings at this time:
4301 *
4302 * 		* **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
4303 * 		  with CHECKSUM_UNNECESSARY.
4304 * 		* **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
4305 * 		  with CHECKSUM_UNNECESSARY.
4306 * 		* **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
4307 * 		  sets CHECKSUM_NONE to force checksum validation by the stack.
4308 * 		* **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
4309 * 		  skb->csum_level.
4310 * 	Return
4311 * 		0 on success, or a negative error in case of failure. In the
4312 * 		case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
4313 * 		is returned or the error code -EACCES in case the skb is not
4314 * 		subject to CHECKSUM_UNNECESSARY.
4315 *
4316 * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
4317 *	Description
4318 *		Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
4319 *	Return
4320 *		*sk* if casting is valid, or **NULL** otherwise.
4321 *
4322 * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
4323 *	Description
4324 *		Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
4325 *	Return
4326 *		*sk* if casting is valid, or **NULL** otherwise.
4327 *
4328 * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
4329 * 	Description
4330 *		Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
4331 *	Return
4332 *		*sk* if casting is valid, or **NULL** otherwise.
4333 *
4334 * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
4335 * 	Description
4336 *		Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
4337 *	Return
4338 *		*sk* if casting is valid, or **NULL** otherwise.
4339 *
4340 * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
4341 * 	Description
4342 *		Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
4343 *	Return
4344 *		*sk* if casting is valid, or **NULL** otherwise.
4345 *
4346 * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
4347 *	Description
4348 *		Return a user or a kernel stack in bpf program provided buffer.
4349 *		To achieve this, the helper needs *task*, which is a valid
4350 *		pointer to **struct task_struct**. To store the stacktrace, the
4351 *		bpf program provides *buf* with a nonnegative *size*.
4352 *
4353 *		The last argument, *flags*, holds the number of stack frames to
4354 *		skip (from 0 to 255), masked with
4355 *		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
4356 *		the following flags:
4357 *
4358 *		**BPF_F_USER_STACK**
4359 *			Collect a user space stack instead of a kernel stack.
4360 *		**BPF_F_USER_BUILD_ID**
4361 *			Collect buildid+offset instead of ips for user stack,
4362 *			only valid if **BPF_F_USER_STACK** is also specified.
4363 *
4364 *		**bpf_get_task_stack**\ () can collect up to
4365 *		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
4366 *		to sufficient large buffer size. Note that
4367 *		this limit can be controlled with the **sysctl** program, and
4368 *		that it should be manually increased in order to profile long
4369 *		user stacks (such as stacks for Java programs). To do so, use:
4370 *
4371 *		::
4372 *
4373 *			# sysctl kernel.perf_event_max_stack=<new value>
4374 *	Return
4375 * 		The non-negative copied *buf* length equal to or less than
4376 * 		*size* on success, or a negative error in case of failure.
4377 *
4378 * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
4379 *	Description
4380 *		Load header option.  Support reading a particular TCP header
4381 *		option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
4382 *
4383 *		If *flags* is 0, it will search the option from the
4384 *		*skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
4385 *		has details on what skb_data contains under different
4386 *		*skops*\ **->op**.
4387 *
4388 *		The first byte of the *searchby_res* specifies the
4389 *		kind that it wants to search.
4390 *
4391 *		If the searching kind is an experimental kind
4392 *		(i.e. 253 or 254 according to RFC6994).  It also
4393 *		needs to specify the "magic" which is either
4394 *		2 bytes or 4 bytes.  It then also needs to
4395 *		specify the size of the magic by using
4396 *		the 2nd byte which is "kind-length" of a TCP
4397 *		header option and the "kind-length" also
4398 *		includes the first 2 bytes "kind" and "kind-length"
4399 *		itself as a normal TCP header option also does.
4400 *
4401 *		For example, to search experimental kind 254 with
4402 *		2 byte magic 0xeB9F, the searchby_res should be
4403 *		[ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4404 *
4405 *		To search for the standard window scale option (3),
4406 *		the *searchby_res* should be [ 3, 0, 0, .... 0 ].
4407 *		Note, kind-length must be 0 for regular option.
4408 *
4409 *		Searching for No-Op (0) and End-of-Option-List (1) are
4410 *		not supported.
4411 *
4412 *		*len* must be at least 2 bytes which is the minimal size
4413 *		of a header option.
4414 *
4415 *		Supported flags:
4416 *
4417 *		* **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
4418 *		  saved_syn packet or the just-received syn packet.
4419 *
4420 *	Return
4421 *		> 0 when found, the header option is copied to *searchby_res*.
4422 *		The return value is the total length copied. On failure, a
4423 *		negative error code is returned:
4424 *
4425 *		**-EINVAL** if a parameter is invalid.
4426 *
4427 *		**-ENOMSG** if the option is not found.
4428 *
4429 *		**-ENOENT** if no syn packet is available when
4430 *		**BPF_LOAD_HDR_OPT_TCP_SYN** is used.
4431 *
4432 *		**-ENOSPC** if there is not enough space.  Only *len* number of
4433 *		bytes are copied.
4434 *
4435 *		**-EFAULT** on failure to parse the header options in the
4436 *		packet.
4437 *
4438 *		**-EPERM** if the helper cannot be used under the current
4439 *		*skops*\ **->op**.
4440 *
4441 * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
4442 *	Description
4443 *		Store header option.  The data will be copied
4444 *		from buffer *from* with length *len* to the TCP header.
4445 *
4446 *		The buffer *from* should have the whole option that
4447 *		includes the kind, kind-length, and the actual
4448 *		option data.  The *len* must be at least kind-length
4449 *		long.  The kind-length does not have to be 4 byte
4450 *		aligned.  The kernel will take care of the padding
4451 *		and setting the 4 bytes aligned value to th->doff.
4452 *
4453 *		This helper will check for duplicated option
4454 *		by searching the same option in the outgoing skb.
4455 *
4456 *		This helper can only be called during
4457 *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4458 *
4459 *	Return
4460 *		0 on success, or negative error in case of failure:
4461 *
4462 *		**-EINVAL** If param is invalid.
4463 *
4464 *		**-ENOSPC** if there is not enough space in the header.
4465 *		Nothing has been written
4466 *
4467 *		**-EEXIST** if the option already exists.
4468 *
4469 *		**-EFAULT** on failure to parse the existing header options.
4470 *
4471 *		**-EPERM** if the helper cannot be used under the current
4472 *		*skops*\ **->op**.
4473 *
4474 * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4475 *	Description
4476 *		Reserve *len* bytes for the bpf header option.  The
4477 *		space will be used by **bpf_store_hdr_opt**\ () later in
4478 *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4479 *
4480 *		If **bpf_reserve_hdr_opt**\ () is called multiple times,
4481 *		the total number of bytes will be reserved.
4482 *
4483 *		This helper can only be called during
4484 *		**BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
4485 *
4486 *	Return
4487 *		0 on success, or negative error in case of failure:
4488 *
4489 *		**-EINVAL** if a parameter is invalid.
4490 *
4491 *		**-ENOSPC** if there is not enough space in the header.
4492 *
4493 *		**-EPERM** if the helper cannot be used under the current
4494 *		*skops*\ **->op**.
4495 *
4496 * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
4497 *	Description
4498 *		Get a bpf_local_storage from an *inode*.
4499 *
4500 *		Logically, it could be thought of as getting the value from
4501 *		a *map* with *inode* as the **key**.  From this
4502 *		perspective,  the usage is not much different from
4503 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
4504 *		helper enforces the key must be an inode and the map must also
4505 *		be a **BPF_MAP_TYPE_INODE_STORAGE**.
4506 *
4507 *		Underneath, the value is stored locally at *inode* instead of
4508 *		the *map*.  The *map* is used as the bpf-local-storage
4509 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4510 *		searched against all bpf_local_storage residing at *inode*.
4511 *
4512 *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4513 *		used such that a new bpf_local_storage will be
4514 *		created if one does not exist.  *value* can be used
4515 *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4516 *		the initial value of a bpf_local_storage.  If *value* is
4517 *		**NULL**, the new bpf_local_storage will be zero initialized.
4518 *	Return
4519 *		A bpf_local_storage pointer is returned on success.
4520 *
4521 *		**NULL** if not found or there was an error in adding
4522 *		a new bpf_local_storage.
4523 *
4524 * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
4525 *	Description
4526 *		Delete a bpf_local_storage from an *inode*.
4527 *	Return
4528 *		0 on success.
4529 *
4530 *		**-ENOENT** if the bpf_local_storage cannot be found.
4531 *
4532 * long bpf_d_path(struct path *path, char *buf, u32 sz)
4533 *	Description
4534 *		Return full path for given **struct path** object, which
4535 *		needs to be the kernel BTF *path* object. The path is
4536 *		returned in the provided buffer *buf* of size *sz* and
4537 *		is zero terminated.
4538 *
4539 *	Return
4540 *		On success, the strictly positive length of the string,
4541 *		including the trailing NUL character. On error, a negative
4542 *		value.
4543 *
4544 * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
4545 * 	Description
4546 * 		Read *size* bytes from user space address *user_ptr* and store
4547 * 		the data in *dst*. This is a wrapper of **copy_from_user**\ ().
4548 * 	Return
4549 * 		0 on success, or a negative error in case of failure.
4550 *
4551 * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
4552 *	Description
4553 *		Use BTF to store a string representation of *ptr*->ptr in *str*,
4554 *		using *ptr*->type_id.  This value should specify the type
4555 *		that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4556 *		can be used to look up vmlinux BTF type ids. Traversing the
4557 *		data structure using BTF, the type information and values are
4558 *		stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
4559 *		the pointer data is carried out to avoid kernel crashes during
4560 *		operation.  Smaller types can use string space on the stack;
4561 *		larger programs can use map data to store the string
4562 *		representation.
4563 *
4564 *		The string can be subsequently shared with userspace via
4565 *		bpf_perf_event_output() or ring buffer interfaces.
4566 *		bpf_trace_printk() is to be avoided as it places too small
4567 *		a limit on string size to be useful.
4568 *
4569 *		*flags* is a combination of
4570 *
4571 *		**BTF_F_COMPACT**
4572 *			no formatting around type information
4573 *		**BTF_F_NONAME**
4574 *			no struct/union member names/types
4575 *		**BTF_F_PTR_RAW**
4576 *			show raw (unobfuscated) pointer values;
4577 *			equivalent to printk specifier %px.
4578 *		**BTF_F_ZERO**
4579 *			show zero-valued struct/union members; they
4580 *			are not displayed by default
4581 *
4582 *	Return
4583 *		The number of bytes that were written (or would have been
4584 *		written if output had to be truncated due to string size),
4585 *		or a negative error in cases of failure.
4586 *
4587 * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
4588 *	Description
4589 *		Use BTF to write to seq_write a string representation of
4590 *		*ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
4591 *		*flags* are identical to those used for bpf_snprintf_btf.
4592 *	Return
4593 *		0 on success or a negative error in case of failure.
4594 *
4595 * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4596 * 	Description
4597 * 		See **bpf_get_cgroup_classid**\ () for the main description.
4598 * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
4599 * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
4600 * 		associated socket instead of the current process.
4601 * 	Return
4602 * 		The id is returned or 0 in case the id could not be retrieved.
4603 *
4604 * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4605 * 	Description
4606 * 		Redirect the packet to another net device of index *ifindex*
4607 * 		and fill in L2 addresses from neighboring subsystem. This helper
4608 * 		is somewhat similar to **bpf_redirect**\ (), except that it
4609 * 		populates L2 addresses as well, meaning, internally, the helper
4610 * 		relies on the neighbor lookup for the L2 address of the nexthop.
4611 *
4612 * 		The helper will perform a FIB lookup based on the skb's
4613 * 		networking header to get the address of the next hop, unless
4614 * 		this is supplied by the caller in the *params* argument. The
4615 * 		*plen* argument indicates the len of *params* and should be set
4616 * 		to 0 if *params* is NULL.
4617 *
4618 * 		The *flags* argument is reserved and must be 0. The helper is
4619 * 		currently only supported for tc BPF program types, and enabled
4620 * 		for IPv4 and IPv6 protocols.
4621 * 	Return
4622 * 		The helper returns **TC_ACT_REDIRECT** on success or
4623 * 		**TC_ACT_SHOT** on error.
4624 *
4625 * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
4626 *     Description
4627 *             Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4628 *             pointer to the percpu kernel variable on *cpu*. A ksym is an
4629 *             extern variable decorated with '__ksym'. For ksym, there is a
4630 *             global var (either static or global) defined of the same name
4631 *             in the kernel. The ksym is percpu if the global var is percpu.
4632 *             The returned pointer points to the global percpu var on *cpu*.
4633 *
4634 *             bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4635 *             kernel, except that bpf_per_cpu_ptr() may return NULL. This
4636 *             happens if *cpu* is larger than nr_cpu_ids. The caller of
4637 *             bpf_per_cpu_ptr() must check the returned value.
4638 *     Return
4639 *             A pointer pointing to the kernel percpu variable on *cpu*, or
4640 *             NULL, if *cpu* is invalid.
4641 *
4642 * void *bpf_this_cpu_ptr(const void *percpu_ptr)
4643 *	Description
4644 *		Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4645 *		pointer to the percpu kernel variable on this cpu. See the
4646 *		description of 'ksym' in **bpf_per_cpu_ptr**\ ().
4647 *
4648 *		bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4649 *		the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
4650 *		never return NULL.
4651 *	Return
4652 *		A pointer pointing to the kernel percpu variable on this cpu.
4653 *
4654 * long bpf_redirect_peer(u32 ifindex, u64 flags)
4655 * 	Description
4656 * 		Redirect the packet to another net device of index *ifindex*.
4657 * 		This helper is somewhat similar to **bpf_redirect**\ (), except
4658 * 		that the redirection happens to the *ifindex*' peer device and
4659 * 		the netns switch takes place from ingress to ingress without
4660 * 		going through the CPU's backlog queue.
4661 *
4662 * 		The *flags* argument is reserved and must be 0. The helper is
4663 * 		currently only supported for tc BPF program types at the ingress
4664 * 		hook and for veth device types. The peer device must reside in a
4665 * 		different network namespace.
4666 * 	Return
4667 * 		The helper returns **TC_ACT_REDIRECT** on success or
4668 * 		**TC_ACT_SHOT** on error.
4669 *
4670 * void *bpf_task_storage_get(struct bpf_map *map, struct task_struct *task, void *value, u64 flags)
4671 *	Description
4672 *		Get a bpf_local_storage from the *task*.
4673 *
4674 *		Logically, it could be thought of as getting the value from
4675 *		a *map* with *task* as the **key**.  From this
4676 *		perspective,  the usage is not much different from
4677 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
4678 *		helper enforces the key must be a task_struct and the map must also
4679 *		be a **BPF_MAP_TYPE_TASK_STORAGE**.
4680 *
4681 *		Underneath, the value is stored locally at *task* instead of
4682 *		the *map*.  The *map* is used as the bpf-local-storage
4683 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4684 *		searched against all bpf_local_storage residing at *task*.
4685 *
4686 *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4687 *		used such that a new bpf_local_storage will be
4688 *		created if one does not exist.  *value* can be used
4689 *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4690 *		the initial value of a bpf_local_storage.  If *value* is
4691 *		**NULL**, the new bpf_local_storage will be zero initialized.
4692 *	Return
4693 *		A bpf_local_storage pointer is returned on success.
4694 *
4695 *		**NULL** if not found or there was an error in adding
4696 *		a new bpf_local_storage.
4697 *
4698 * long bpf_task_storage_delete(struct bpf_map *map, struct task_struct *task)
4699 *	Description
4700 *		Delete a bpf_local_storage from a *task*.
4701 *	Return
4702 *		0 on success.
4703 *
4704 *		**-ENOENT** if the bpf_local_storage cannot be found.
4705 *
4706 * struct task_struct *bpf_get_current_task_btf(void)
4707 *	Description
4708 *		Return a BTF pointer to the "current" task.
4709 *		This pointer can also be used in helpers that accept an
4710 *		*ARG_PTR_TO_BTF_ID* of type *task_struct*.
4711 *	Return
4712 *		Pointer to the current task.
4713 *
4714 * long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4715 *	Description
4716 *		Set or clear certain options on *bprm*:
4717 *
4718 *		**BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
4719 *		which sets the **AT_SECURE** auxv for glibc. The bit
4720 *		is cleared if the flag is not specified.
4721 *	Return
4722 *		**-EINVAL** if invalid *flags* are passed, zero otherwise.
4723 *
4724 * u64 bpf_ktime_get_coarse_ns(void)
4725 * 	Description
4726 * 		Return a coarse-grained version of the time elapsed since
4727 * 		system boot, in nanoseconds. Does not include time the system
4728 * 		was suspended.
4729 *
4730 * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
4731 * 	Return
4732 * 		Current *ktime*.
4733 *
4734 * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
4735 *	Description
4736 *		Returns the stored IMA hash of the *inode* (if it's available).
4737 *		If the hash is larger than *size*, then only *size*
4738 *		bytes will be copied to *dst*
4739 *	Return
4740 *		The **hash_algo** is returned on success,
4741 *		**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
4742 *		invalid arguments are passed.
4743 *
4744 * struct socket *bpf_sock_from_file(struct file *file)
4745 *	Description
4746 *		If the given file represents a socket, returns the associated
4747 *		socket.
4748 *	Return
4749 *		A pointer to a struct socket on success or NULL if the file is
4750 *		not a socket.
4751 *
4752 * long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
4753 *	Description
4754 *		Check packet size against exceeding MTU of net device (based
4755 *		on *ifindex*).  This helper will likely be used in combination
4756 *		with helpers that adjust/change the packet size.
4757 *
4758 *		The argument *len_diff* can be used for querying with a planned
4759 *		size change. This allows to check MTU prior to changing packet
4760 *		ctx. Providing a *len_diff* adjustment that is larger than the
4761 *		actual packet size (resulting in negative packet size) will in
4762 *		principle not exceed the MTU, which is why it is not considered
4763 *		a failure.  Other BPF helpers are needed for performing the
4764 *		planned size change; therefore the responsibility for catching
4765 *		a negative packet size belongs in those helpers.
4766 *
4767 *		Specifying *ifindex* zero means the MTU check is performed
4768 *		against the current net device.  This is practical if this isn't
4769 *		used prior to redirect.
4770 *
4771 *		On input *mtu_len* must be a valid pointer, else verifier will
4772 *		reject BPF program.  If the value *mtu_len* is initialized to
4773 *		zero then the ctx packet size is use.  When value *mtu_len* is
4774 *		provided as input this specify the L3 length that the MTU check
4775 *		is done against. Remember XDP and TC length operate at L2, but
4776 *		this value is L3 as this correlate to MTU and IP-header tot_len
4777 *		values which are L3 (similar behavior as bpf_fib_lookup).
4778 *
4779 *		The Linux kernel route table can configure MTUs on a more
4780 *		specific per route level, which is not provided by this helper.
4781 *		For route level MTU checks use the **bpf_fib_lookup**\ ()
4782 *		helper.
4783 *
4784 *		*ctx* is either **struct xdp_md** for XDP programs or
4785 *		**struct sk_buff** for tc cls_act programs.
4786 *
4787 *		The *flags* argument can be a combination of one or more of the
4788 *		following values:
4789 *
4790 *		**BPF_MTU_CHK_SEGS**
4791 *			This flag will only works for *ctx* **struct sk_buff**.
4792 *			If packet context contains extra packet segment buffers
4793 *			(often knows as GSO skb), then MTU check is harder to
4794 *			check at this point, because in transmit path it is
4795 *			possible for the skb packet to get re-segmented
4796 *			(depending on net device features).  This could still be
4797 *			a MTU violation, so this flag enables performing MTU
4798 *			check against segments, with a different violation
4799 *			return code to tell it apart. Check cannot use len_diff.
4800 *
4801 *		On return *mtu_len* pointer contains the MTU value of the net
4802 *		device.  Remember the net device configured MTU is the L3 size,
4803 *		which is returned here and XDP and TC length operate at L2.
4804 *		Helper take this into account for you, but remember when using
4805 *		MTU value in your BPF-code.
4806 *
4807 *	Return
4808 *		* 0 on success, and populate MTU value in *mtu_len* pointer.
4809 *
4810 *		* < 0 if any input argument is invalid (*mtu_len* not updated)
4811 *
4812 *		MTU violations return positive values, but also populate MTU
4813 *		value in *mtu_len* pointer, as this can be needed for
4814 *		implementing PMTU handing:
4815 *
4816 *		* **BPF_MTU_CHK_RET_FRAG_NEEDED**
4817 *		* **BPF_MTU_CHK_RET_SEGS_TOOBIG**
4818 *
4819 * long bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, void *callback_ctx, u64 flags)
4820 *	Description
4821 *		For each element in **map**, call **callback_fn** function with
4822 *		**map**, **callback_ctx** and other map-specific parameters.
4823 *		The **callback_fn** should be a static function and
4824 *		the **callback_ctx** should be a pointer to the stack.
4825 *		The **flags** is used to control certain aspects of the helper.
4826 *		Currently, the **flags** must be 0.
4827 *
4828 *		The following are a list of supported map types and their
4829 *		respective expected callback signatures:
4830 *
4831 *		BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4832 *		BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4833 *		BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4834 *
4835 *		long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
4836 *
4837 *		For per_cpu maps, the map_value is the value on the cpu where the
4838 *		bpf_prog is running.
4839 *
4840 *		If **callback_fn** return 0, the helper will continue to the next
4841 *		element. If return value is 1, the helper will skip the rest of
4842 *		elements and return. Other return values are not used now.
4843 *
4844 *	Return
4845 *		The number of traversed map elements for success, **-EINVAL** for
4846 *		invalid **flags**.
4847 *
4848 * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len)
4849 *	Description
4850 *		Outputs a string into the **str** buffer of size **str_size**
4851 *		based on a format string stored in a read-only map pointed by
4852 *		**fmt**.
4853 *
4854 *		Each format specifier in **fmt** corresponds to one u64 element
4855 *		in the **data** array. For strings and pointers where pointees
4856 *		are accessed, only the pointer values are stored in the *data*
4857 *		array. The *data_len* is the size of *data* in bytes - must be
4858 *		a multiple of 8.
4859 *
4860 *		Formats **%s** and **%p{i,I}{4,6}** require to read kernel
4861 *		memory. Reading kernel memory may fail due to either invalid
4862 *		address or valid address but requiring a major memory fault. If
4863 *		reading kernel memory fails, the string for **%s** will be an
4864 *		empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
4865 *		Not returning error to bpf program is consistent with what
4866 *		**bpf_trace_printk**\ () does for now.
4867 *
4868 *	Return
4869 *		The strictly positive length of the formatted string, including
4870 *		the trailing zero character. If the return value is greater than
4871 *		**str_size**, **str** contains a truncated string, guaranteed to
4872 *		be zero-terminated except when **str_size** is 0.
4873 *
4874 *		Or **-EBUSY** if the per-CPU memory copy buffer is busy.
4875 *
4876 * long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4877 * 	Description
4878 * 		Execute bpf syscall with given arguments.
4879 * 	Return
4880 * 		A syscall result.
4881 *
4882 * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4883 * 	Description
4884 * 		Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4885 * 	Return
4886 * 		Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4887 *
4888 * long bpf_sys_close(u32 fd)
4889 * 	Description
4890 * 		Execute close syscall for given FD.
4891 * 	Return
4892 * 		A syscall result.
4893 *
4894 * long bpf_timer_init(struct bpf_timer *timer, struct bpf_map *map, u64 flags)
4895 *	Description
4896 *		Initialize the timer.
4897 *		First 4 bits of *flags* specify clockid.
4898 *		Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4899 *		All other bits of *flags* are reserved.
4900 *		The verifier will reject the program if *timer* is not from
4901 *		the same *map*.
4902 *	Return
4903 *		0 on success.
4904 *		**-EBUSY** if *timer* is already initialized.
4905 *		**-EINVAL** if invalid *flags* are passed.
4906 *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4907 *		The user space should either hold a file descriptor to a map with timers
4908 *		or pin such map in bpffs. When map is unpinned or file descriptor is
4909 *		closed all timers in the map will be cancelled and freed.
4910 *
4911 * long bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn)
4912 *	Description
4913 *		Configure the timer to call *callback_fn* static function.
4914 *	Return
4915 *		0 on success.
4916 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4917 *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4918 *		The user space should either hold a file descriptor to a map with timers
4919 *		or pin such map in bpffs. When map is unpinned or file descriptor is
4920 *		closed all timers in the map will be cancelled and freed.
4921 *
4922 * long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4923 *	Description
4924 *		Set timer expiration N nanoseconds from the current time. The
4925 *		configured callback will be invoked in soft irq context on some cpu
4926 *		and will not repeat unless another bpf_timer_start() is made.
4927 *		In such case the next invocation can migrate to a different cpu.
4928 *		Since struct bpf_timer is a field inside map element the map
4929 *		owns the timer. The bpf_timer_set_callback() will increment refcnt
4930 *		of BPF program to make sure that callback_fn code stays valid.
4931 *		When user space reference to a map reaches zero all timers
4932 *		in a map are cancelled and corresponding program's refcnts are
4933 *		decremented. This is done to make sure that Ctrl-C of a user
4934 *		process doesn't leave any timers running. If map is pinned in
4935 *		bpffs the callback_fn can re-arm itself indefinitely.
4936 *		bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4937 *		cancel and free the timer in the given map element.
4938 *		The map can contain timers that invoke callback_fn-s from different
4939 *		programs. The same callback_fn can serve different timers from
4940 *		different maps if key/value layout matches across maps.
4941 *		Every bpf_timer_set_callback() can have different callback_fn.
4942 *
4943 *	Return
4944 *		0 on success.
4945 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
4946 *		or invalid *flags* are passed.
4947 *
4948 * long bpf_timer_cancel(struct bpf_timer *timer)
4949 *	Description
4950 *		Cancel the timer and wait for callback_fn to finish if it was running.
4951 *	Return
4952 *		0 if the timer was not active.
4953 *		1 if the timer was active.
4954 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4955 *		**-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
4956 *		own timer which would have led to a deadlock otherwise.
4957 *
4958 * u64 bpf_get_func_ip(void *ctx)
4959 * 	Description
4960 * 		Get address of the traced function (for tracing and kprobe programs).
4961 * 	Return
4962 * 		Address of the traced function.
4963 * 		0 for kprobes placed within the function (not at the entry).
4964 *
4965 * u64 bpf_get_attach_cookie(void *ctx)
4966 * 	Description
4967 * 		Get bpf_cookie value provided (optionally) during the program
4968 * 		attachment. It might be different for each individual
4969 * 		attachment, even if BPF program itself is the same.
4970 * 		Expects BPF program context *ctx* as a first argument.
4971 *
4972 * 		Supported for the following program types:
4973 *			- kprobe/uprobe;
4974 *			- tracepoint;
4975 *			- perf_event.
4976 * 	Return
4977 *		Value specified by user at BPF link creation/attachment time
4978 *		or 0, if it was not specified.
4979 *
4980 * long bpf_task_pt_regs(struct task_struct *task)
4981 *	Description
4982 *		Get the struct pt_regs associated with **task**.
4983 *	Return
4984 *		A pointer to struct pt_regs.
4985 *
4986 * long bpf_get_branch_snapshot(void *entries, u32 size, u64 flags)
4987 *	Description
4988 *		Get branch trace from hardware engines like Intel LBR. The
4989 *		hardware engine is stopped shortly after the helper is
4990 *		called. Therefore, the user need to filter branch entries
4991 *		based on the actual use case. To capture branch trace
4992 *		before the trigger point of the BPF program, the helper
4993 *		should be called at the beginning of the BPF program.
4994 *
4995 *		The data is stored as struct perf_branch_entry into output
4996 *		buffer *entries*. *size* is the size of *entries* in bytes.
4997 *		*flags* is reserved for now and must be zero.
4998 *
4999 *	Return
5000 *		On success, number of bytes written to *buf*. On error, a
5001 *		negative value.
5002 *
5003 *		**-EINVAL** if *flags* is not zero.
5004 *
5005 *		**-ENOENT** if architecture does not support branch records.
5006 *
5007 * long bpf_trace_vprintk(const char *fmt, u32 fmt_size, const void *data, u32 data_len)
5008 *	Description
5009 *		Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64
5010 *		to format and can handle more format args as a result.
5011 *
5012 *		Arguments are to be used as in **bpf_seq_printf**\ () helper.
5013 *	Return
5014 *		The number of bytes written to the buffer, or a negative error
5015 *		in case of failure.
5016 *
5017 * struct unix_sock *bpf_skc_to_unix_sock(void *sk)
5018 * 	Description
5019 *		Dynamically cast a *sk* pointer to a *unix_sock* pointer.
5020 *	Return
5021 *		*sk* if casting is valid, or **NULL** otherwise.
5022 *
5023 * long bpf_kallsyms_lookup_name(const char *name, int name_sz, int flags, u64 *res)
5024 *	Description
5025 *		Get the address of a kernel symbol, returned in *res*. *res* is
5026 *		set to 0 if the symbol is not found.
5027 *	Return
5028 *		On success, zero. On error, a negative value.
5029 *
5030 *		**-EINVAL** if *flags* is not zero.
5031 *
5032 *		**-EINVAL** if string *name* is not the same size as *name_sz*.
5033 *
5034 *		**-ENOENT** if symbol is not found.
5035 *
5036 *		**-EPERM** if caller does not have permission to obtain kernel address.
5037 *
5038 * long bpf_find_vma(struct task_struct *task, u64 addr, void *callback_fn, void *callback_ctx, u64 flags)
5039 *	Description
5040 *		Find vma of *task* that contains *addr*, call *callback_fn*
5041 *		function with *task*, *vma*, and *callback_ctx*.
5042 *		The *callback_fn* should be a static function and
5043 *		the *callback_ctx* should be a pointer to the stack.
5044 *		The *flags* is used to control certain aspects of the helper.
5045 *		Currently, the *flags* must be 0.
5046 *
5047 *		The expected callback signature is
5048 *
5049 *		long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
5050 *
5051 *	Return
5052 *		0 on success.
5053 *		**-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
5054 *		**-EBUSY** if failed to try lock mmap_lock.
5055 *		**-EINVAL** for invalid **flags**.
5056 *
5057 * long bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx, u64 flags)
5058 *	Description
5059 *		For **nr_loops**, call **callback_fn** function
5060 *		with **callback_ctx** as the context parameter.
5061 *		The **callback_fn** should be a static function and
5062 *		the **callback_ctx** should be a pointer to the stack.
5063 *		The **flags** is used to control certain aspects of the helper.
5064 *		Currently, the **flags** must be 0. Currently, nr_loops is
5065 *		limited to 1 << 23 (~8 million) loops.
5066 *
5067 *		long (\*callback_fn)(u32 index, void \*ctx);
5068 *
5069 *		where **index** is the current index in the loop. The index
5070 *		is zero-indexed.
5071 *
5072 *		If **callback_fn** returns 0, the helper will continue to the next
5073 *		loop. If return value is 1, the helper will skip the rest of
5074 *		the loops and return. Other return values are not used now,
5075 *		and will be rejected by the verifier.
5076 *
5077 *	Return
5078 *		The number of loops performed, **-EINVAL** for invalid **flags**,
5079 *		**-E2BIG** if **nr_loops** exceeds the maximum number of loops.
5080 *
5081 * long bpf_strncmp(const char *s1, u32 s1_sz, const char *s2)
5082 *	Description
5083 *		Do strncmp() between **s1** and **s2**. **s1** doesn't need
5084 *		to be null-terminated and **s1_sz** is the maximum storage
5085 *		size of **s1**. **s2** must be a read-only string.
5086 *	Return
5087 *		An integer less than, equal to, or greater than zero
5088 *		if the first **s1_sz** bytes of **s1** is found to be
5089 *		less than, to match, or be greater than **s2**.
5090 *
5091 * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
5092 *	Description
5093 *		Get **n**-th argument register (zero based) of the traced function (for tracing programs)
5094 *		returned in **value**.
5095 *
5096 *	Return
5097 *		0 on success.
5098 *		**-EINVAL** if n >= argument register count of traced function.
5099 *
5100 * long bpf_get_func_ret(void *ctx, u64 *value)
5101 *	Description
5102 *		Get return value of the traced function (for tracing programs)
5103 *		in **value**.
5104 *
5105 *	Return
5106 *		0 on success.
5107 *		**-EOPNOTSUPP** for tracing programs other than BPF_TRACE_FEXIT or BPF_MODIFY_RETURN.
5108 *
5109 * long bpf_get_func_arg_cnt(void *ctx)
5110 *	Description
5111 *		Get number of registers of the traced function (for tracing programs) where
5112 *		function arguments are stored in these registers.
5113 *
5114 *	Return
5115 *		The number of argument registers of the traced function.
5116 *
5117 * int bpf_get_retval(void)
5118 *	Description
5119 *		Get the BPF program's return value that will be returned to the upper layers.
5120 *
5121 *		This helper is currently supported by cgroup programs and only by the hooks
5122 *		where BPF program's return value is returned to the userspace via errno.
5123 *	Return
5124 *		The BPF program's return value.
5125 *
5126 * int bpf_set_retval(int retval)
5127 *	Description
5128 *		Set the BPF program's return value that will be returned to the upper layers.
5129 *
5130 *		This helper is currently supported by cgroup programs and only by the hooks
5131 *		where BPF program's return value is returned to the userspace via errno.
5132 *
5133 *		Note that there is the following corner case where the program exports an error
5134 *		via bpf_set_retval but signals success via 'return 1':
5135 *
5136 *			bpf_set_retval(-EPERM);
5137 *			return 1;
5138 *
5139 *		In this case, the BPF program's return value will use helper's -EPERM. This
5140 *		still holds true for cgroup/bind{4,6} which supports extra 'return 3' success case.
5141 *
5142 *	Return
5143 *		0 on success, or a negative error in case of failure.
5144 *
5145 * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)
5146 *	Description
5147 *		Get the total size of a given xdp buff (linear and paged area)
5148 *	Return
5149 *		The total size of a given xdp buffer.
5150 *
5151 * long bpf_xdp_load_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
5152 *	Description
5153 *		This helper is provided as an easy way to load data from a
5154 *		xdp buffer. It can be used to load *len* bytes from *offset* from
5155 *		the frame associated to *xdp_md*, into the buffer pointed by
5156 *		*buf*.
5157 *	Return
5158 *		0 on success, or a negative error in case of failure.
5159 *
5160 * long bpf_xdp_store_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
5161 *	Description
5162 *		Store *len* bytes from buffer *buf* into the frame
5163 *		associated to *xdp_md*, at *offset*.
5164 *	Return
5165 *		0 on success, or a negative error in case of failure.
5166 *
5167 * long bpf_copy_from_user_task(void *dst, u32 size, const void *user_ptr, struct task_struct *tsk, u64 flags)
5168 *	Description
5169 *		Read *size* bytes from user space address *user_ptr* in *tsk*'s
5170 *		address space, and stores the data in *dst*. *flags* is not
5171 *		used yet and is provided for future extensibility. This helper
5172 *		can only be used by sleepable programs.
5173 *	Return
5174 *		0 on success, or a negative error in case of failure. On error
5175 *		*dst* buffer is zeroed out.
5176 *
5177 * long bpf_skb_set_tstamp(struct sk_buff *skb, u64 tstamp, u32 tstamp_type)
5178 *	Description
5179 *		Change the __sk_buff->tstamp_type to *tstamp_type*
5180 *		and set *tstamp* to the __sk_buff->tstamp together.
5181 *
5182 *		If there is no need to change the __sk_buff->tstamp_type,
5183 *		the tstamp value can be directly written to __sk_buff->tstamp
5184 *		instead.
5185 *
5186 *		BPF_SKB_TSTAMP_DELIVERY_MONO is the only tstamp that
5187 *		will be kept during bpf_redirect_*().  A non zero
5188 *		*tstamp* must be used with the BPF_SKB_TSTAMP_DELIVERY_MONO
5189 *		*tstamp_type*.
5190 *
5191 *		A BPF_SKB_TSTAMP_UNSPEC *tstamp_type* can only be used
5192 *		with a zero *tstamp*.
5193 *
5194 *		Only IPv4 and IPv6 skb->protocol are supported.
5195 *
5196 *		This function is most useful when it needs to set a
5197 *		mono delivery time to __sk_buff->tstamp and then
5198 *		bpf_redirect_*() to the egress of an iface.  For example,
5199 *		changing the (rcv) timestamp in __sk_buff->tstamp at
5200 *		ingress to a mono delivery time and then bpf_redirect_*()
5201 *		to sch_fq@phy-dev.
5202 *	Return
5203 *		0 on success.
5204 *		**-EINVAL** for invalid input
5205 *		**-EOPNOTSUPP** for unsupported protocol
5206 *
5207 * long bpf_ima_file_hash(struct file *file, void *dst, u32 size)
5208 *	Description
5209 *		Returns a calculated IMA hash of the *file*.
5210 *		If the hash is larger than *size*, then only *size*
5211 *		bytes will be copied to *dst*
5212 *	Return
5213 *		The **hash_algo** is returned on success,
5214 *		**-EOPNOTSUP** if the hash calculation failed or **-EINVAL** if
5215 *		invalid arguments are passed.
5216 *
5217 * void *bpf_kptr_xchg(void *map_value, void *ptr)
5218 *	Description
5219 *		Exchange kptr at pointer *map_value* with *ptr*, and return the
5220 *		old value. *ptr* can be NULL, otherwise it must be a referenced
5221 *		pointer which will be released when this helper is called.
5222 *	Return
5223 *		The old value of kptr (which can be NULL). The returned pointer
5224 *		if not NULL, is a reference which must be released using its
5225 *		corresponding release function, or moved into a BPF map before
5226 *		program exit.
5227 *
5228 * void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu)
5229 * 	Description
5230 * 		Perform a lookup in *percpu map* for an entry associated to
5231 * 		*key* on *cpu*.
5232 * 	Return
5233 * 		Map value associated to *key* on *cpu*, or **NULL** if no entry
5234 * 		was found or *cpu* is invalid.
5235 *
5236 * struct mptcp_sock *bpf_skc_to_mptcp_sock(void *sk)
5237 *	Description
5238 *		Dynamically cast a *sk* pointer to a *mptcp_sock* pointer.
5239 *	Return
5240 *		*sk* if casting is valid, or **NULL** otherwise.
5241 *
5242 * long bpf_dynptr_from_mem(void *data, u32 size, u64 flags, struct bpf_dynptr *ptr)
5243 *	Description
5244 *		Get a dynptr to local memory *data*.
5245 *
5246 *		*data* must be a ptr to a map value.
5247 *		The maximum *size* supported is DYNPTR_MAX_SIZE.
5248 *		*flags* is currently unused.
5249 *	Return
5250 *		0 on success, -E2BIG if the size exceeds DYNPTR_MAX_SIZE,
5251 *		-EINVAL if flags is not 0.
5252 *
5253 * long bpf_ringbuf_reserve_dynptr(void *ringbuf, u32 size, u64 flags, struct bpf_dynptr *ptr)
5254 *	Description
5255 *		Reserve *size* bytes of payload in a ring buffer *ringbuf*
5256 *		through the dynptr interface. *flags* must be 0.
5257 *
5258 *		Please note that a corresponding bpf_ringbuf_submit_dynptr or
5259 *		bpf_ringbuf_discard_dynptr must be called on *ptr*, even if the
5260 *		reservation fails. This is enforced by the verifier.
5261 *	Return
5262 *		0 on success, or a negative error in case of failure.
5263 *
5264 * void bpf_ringbuf_submit_dynptr(struct bpf_dynptr *ptr, u64 flags)
5265 *	Description
5266 *		Submit reserved ring buffer sample, pointed to by *data*,
5267 *		through the dynptr interface. This is a no-op if the dynptr is
5268 *		invalid/null.
5269 *
5270 *		For more information on *flags*, please see
5271 *		'bpf_ringbuf_submit'.
5272 *	Return
5273 *		Nothing. Always succeeds.
5274 *
5275 * void bpf_ringbuf_discard_dynptr(struct bpf_dynptr *ptr, u64 flags)
5276 *	Description
5277 *		Discard reserved ring buffer sample through the dynptr
5278 *		interface. This is a no-op if the dynptr is invalid/null.
5279 *
5280 *		For more information on *flags*, please see
5281 *		'bpf_ringbuf_discard'.
5282 *	Return
5283 *		Nothing. Always succeeds.
5284 *
5285 * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset, u64 flags)
5286 *	Description
5287 *		Read *len* bytes from *src* into *dst*, starting from *offset*
5288 *		into *src*.
5289 *		*flags* is currently unused.
5290 *	Return
5291 *		0 on success, -E2BIG if *offset* + *len* exceeds the length
5292 *		of *src*'s data, -EINVAL if *src* is an invalid dynptr or if
5293 *		*flags* is not 0.
5294 *
5295 * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len, u64 flags)
5296 *	Description
5297 *		Write *len* bytes from *src* into *dst*, starting from *offset*
5298 *		into *dst*.
5299 *		*flags* is currently unused.
5300 *	Return
5301 *		0 on success, -E2BIG if *offset* + *len* exceeds the length
5302 *		of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
5303 *		is a read-only dynptr or if *flags* is not 0.
5304 *
5305 * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)
5306 *	Description
5307 *		Get a pointer to the underlying dynptr data.
5308 *
5309 *		*len* must be a statically known value. The returned data slice
5310 *		is invalidated whenever the dynptr is invalidated.
5311 *	Return
5312 *		Pointer to the underlying dynptr data, NULL if the dynptr is
5313 *		read-only, if the dynptr is invalid, or if the offset and length
5314 *		is out of bounds.
5315 *
5316 * s64 bpf_tcp_raw_gen_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th, u32 th_len)
5317 *	Description
5318 *		Try to issue a SYN cookie for the packet with corresponding
5319 *		IPv4/TCP headers, *iph* and *th*, without depending on a
5320 *		listening socket.
5321 *
5322 *		*iph* points to the IPv4 header.
5323 *
5324 *		*th* points to the start of the TCP header, while *th_len*
5325 *		contains the length of the TCP header (at least
5326 *		**sizeof**\ (**struct tcphdr**)).
5327 *	Return
5328 *		On success, lower 32 bits hold the generated SYN cookie in
5329 *		followed by 16 bits which hold the MSS value for that cookie,
5330 *		and the top 16 bits are unused.
5331 *
5332 *		On failure, the returned value is one of the following:
5333 *
5334 *		**-EINVAL** if *th_len* is invalid.
5335 *
5336 * s64 bpf_tcp_raw_gen_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th, u32 th_len)
5337 *	Description
5338 *		Try to issue a SYN cookie for the packet with corresponding
5339 *		IPv6/TCP headers, *iph* and *th*, without depending on a
5340 *		listening socket.
5341 *
5342 *		*iph* points to the IPv6 header.
5343 *
5344 *		*th* points to the start of the TCP header, while *th_len*
5345 *		contains the length of the TCP header (at least
5346 *		**sizeof**\ (**struct tcphdr**)).
5347 *	Return
5348 *		On success, lower 32 bits hold the generated SYN cookie in
5349 *		followed by 16 bits which hold the MSS value for that cookie,
5350 *		and the top 16 bits are unused.
5351 *
5352 *		On failure, the returned value is one of the following:
5353 *
5354 *		**-EINVAL** if *th_len* is invalid.
5355 *
5356 *		**-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin.
5357 *
5358 * long bpf_tcp_raw_check_syncookie_ipv4(struct iphdr *iph, struct tcphdr *th)
5359 *	Description
5360 *		Check whether *iph* and *th* contain a valid SYN cookie ACK
5361 *		without depending on a listening socket.
5362 *
5363 *		*iph* points to the IPv4 header.
5364 *
5365 *		*th* points to the TCP header.
5366 *	Return
5367 *		0 if *iph* and *th* are a valid SYN cookie ACK.
5368 *
5369 *		On failure, the returned value is one of the following:
5370 *
5371 *		**-EACCES** if the SYN cookie is not valid.
5372 *
5373 * long bpf_tcp_raw_check_syncookie_ipv6(struct ipv6hdr *iph, struct tcphdr *th)
5374 *	Description
5375 *		Check whether *iph* and *th* contain a valid SYN cookie ACK
5376 *		without depending on a listening socket.
5377 *
5378 *		*iph* points to the IPv6 header.
5379 *
5380 *		*th* points to the TCP header.
5381 *	Return
5382 *		0 if *iph* and *th* are a valid SYN cookie ACK.
5383 *
5384 *		On failure, the returned value is one of the following:
5385 *
5386 *		**-EACCES** if the SYN cookie is not valid.
5387 *
5388 *		**-EPROTONOSUPPORT** if CONFIG_IPV6 is not builtin.
5389 *
5390 * u64 bpf_ktime_get_tai_ns(void)
5391 *	Description
5392 *		A nonsettable system-wide clock derived from wall-clock time but
5393 *		ignoring leap seconds.  This clock does not experience
5394 *		discontinuities and backwards jumps caused by NTP inserting leap
5395 *		seconds as CLOCK_REALTIME does.
5396 *
5397 *		See: **clock_gettime**\ (**CLOCK_TAI**)
5398 *	Return
5399 *		Current *ktime*.
5400 *
5401 * long bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx, u64 flags)
5402 *	Description
5403 *		Drain samples from the specified user ring buffer, and invoke
5404 *		the provided callback for each such sample:
5405 *
5406 *		long (\*callback_fn)(struct bpf_dynptr \*dynptr, void \*ctx);
5407 *
5408 *		If **callback_fn** returns 0, the helper will continue to try
5409 *		and drain the next sample, up to a maximum of
5410 *		BPF_MAX_USER_RINGBUF_SAMPLES samples. If the return value is 1,
5411 *		the helper will skip the rest of the samples and return. Other
5412 *		return values are not used now, and will be rejected by the
5413 *		verifier.
5414 *	Return
5415 *		The number of drained samples if no error was encountered while
5416 *		draining samples, or 0 if no samples were present in the ring
5417 *		buffer. If a user-space producer was epoll-waiting on this map,
5418 *		and at least one sample was drained, they will receive an event
5419 *		notification notifying them of available space in the ring
5420 *		buffer. If the BPF_RB_NO_WAKEUP flag is passed to this
5421 *		function, no wakeup notification will be sent. If the
5422 *		BPF_RB_FORCE_WAKEUP flag is passed, a wakeup notification will
5423 *		be sent even if no sample was drained.
5424 *
5425 *		On failure, the returned value is one of the following:
5426 *
5427 *		**-EBUSY** if the ring buffer is contended, and another calling
5428 *		context was concurrently draining the ring buffer.
5429 *
5430 *		**-EINVAL** if user-space is not properly tracking the ring
5431 *		buffer due to the producer position not being aligned to 8
5432 *		bytes, a sample not being aligned to 8 bytes, or the producer
5433 *		position not matching the advertised length of a sample.
5434 *
5435 *		**-E2BIG** if user-space has tried to publish a sample which is
5436 *		larger than the size of the ring buffer, or which cannot fit
5437 *		within a struct bpf_dynptr.
5438 */
5439#define __BPF_FUNC_MAPPER(FN)		\
5440	FN(unspec),			\
5441	FN(map_lookup_elem),		\
5442	FN(map_update_elem),		\
5443	FN(map_delete_elem),		\
5444	FN(probe_read),			\
5445	FN(ktime_get_ns),		\
5446	FN(trace_printk),		\
5447	FN(get_prandom_u32),		\
5448	FN(get_smp_processor_id),	\
5449	FN(skb_store_bytes),		\
5450	FN(l3_csum_replace),		\
5451	FN(l4_csum_replace),		\
5452	FN(tail_call),			\
5453	FN(clone_redirect),		\
5454	FN(get_current_pid_tgid),	\
5455	FN(get_current_uid_gid),	\
5456	FN(get_current_comm),		\
5457	FN(get_cgroup_classid),		\
5458	FN(skb_vlan_push),		\
5459	FN(skb_vlan_pop),		\
5460	FN(skb_get_tunnel_key),		\
5461	FN(skb_set_tunnel_key),		\
5462	FN(perf_event_read),		\
5463	FN(redirect),			\
5464	FN(get_route_realm),		\
5465	FN(perf_event_output),		\
5466	FN(skb_load_bytes),		\
5467	FN(get_stackid),		\
5468	FN(csum_diff),			\
5469	FN(skb_get_tunnel_opt),		\
5470	FN(skb_set_tunnel_opt),		\
5471	FN(skb_change_proto),		\
5472	FN(skb_change_type),		\
5473	FN(skb_under_cgroup),		\
5474	FN(get_hash_recalc),		\
5475	FN(get_current_task),		\
5476	FN(probe_write_user),		\
5477	FN(current_task_under_cgroup),	\
5478	FN(skb_change_tail),		\
5479	FN(skb_pull_data),		\
5480	FN(csum_update),		\
5481	FN(set_hash_invalid),		\
5482	FN(get_numa_node_id),		\
5483	FN(skb_change_head),		\
5484	FN(xdp_adjust_head),		\
5485	FN(probe_read_str),		\
5486	FN(get_socket_cookie),		\
5487	FN(get_socket_uid),		\
5488	FN(set_hash),			\
5489	FN(setsockopt),			\
5490	FN(skb_adjust_room),		\
5491	FN(redirect_map),		\
5492	FN(sk_redirect_map),		\
5493	FN(sock_map_update),		\
5494	FN(xdp_adjust_meta),		\
5495	FN(perf_event_read_value),	\
5496	FN(perf_prog_read_value),	\
5497	FN(getsockopt),			\
5498	FN(override_return),		\
5499	FN(sock_ops_cb_flags_set),	\
5500	FN(msg_redirect_map),		\
5501	FN(msg_apply_bytes),		\
5502	FN(msg_cork_bytes),		\
5503	FN(msg_pull_data),		\
5504	FN(bind),			\
5505	FN(xdp_adjust_tail),		\
5506	FN(skb_get_xfrm_state),		\
5507	FN(get_stack),			\
5508	FN(skb_load_bytes_relative),	\
5509	FN(fib_lookup),			\
5510	FN(sock_hash_update),		\
5511	FN(msg_redirect_hash),		\
5512	FN(sk_redirect_hash),		\
5513	FN(lwt_push_encap),		\
5514	FN(lwt_seg6_store_bytes),	\
5515	FN(lwt_seg6_adjust_srh),	\
5516	FN(lwt_seg6_action),		\
5517	FN(rc_repeat),			\
5518	FN(rc_keydown),			\
5519	FN(skb_cgroup_id),		\
5520	FN(get_current_cgroup_id),	\
5521	FN(get_local_storage),		\
5522	FN(sk_select_reuseport),	\
5523	FN(skb_ancestor_cgroup_id),	\
5524	FN(sk_lookup_tcp),		\
5525	FN(sk_lookup_udp),		\
5526	FN(sk_release),			\
5527	FN(map_push_elem),		\
5528	FN(map_pop_elem),		\
5529	FN(map_peek_elem),		\
5530	FN(msg_push_data),		\
5531	FN(msg_pop_data),		\
5532	FN(rc_pointer_rel),		\
5533	FN(spin_lock),			\
5534	FN(spin_unlock),		\
5535	FN(sk_fullsock),		\
5536	FN(tcp_sock),			\
5537	FN(skb_ecn_set_ce),		\
5538	FN(get_listener_sock),		\
5539	FN(skc_lookup_tcp),		\
5540	FN(tcp_check_syncookie),	\
5541	FN(sysctl_get_name),		\
5542	FN(sysctl_get_current_value),	\
5543	FN(sysctl_get_new_value),	\
5544	FN(sysctl_set_new_value),	\
5545	FN(strtol),			\
5546	FN(strtoul),			\
5547	FN(sk_storage_get),		\
5548	FN(sk_storage_delete),		\
5549	FN(send_signal),		\
5550	FN(tcp_gen_syncookie),		\
5551	FN(skb_output),			\
5552	FN(probe_read_user),		\
5553	FN(probe_read_kernel),		\
5554	FN(probe_read_user_str),	\
5555	FN(probe_read_kernel_str),	\
5556	FN(tcp_send_ack),		\
5557	FN(send_signal_thread),		\
5558	FN(jiffies64),			\
5559	FN(read_branch_records),	\
5560	FN(get_ns_current_pid_tgid),	\
5561	FN(xdp_output),			\
5562	FN(get_netns_cookie),		\
5563	FN(get_current_ancestor_cgroup_id),	\
5564	FN(sk_assign),			\
5565	FN(ktime_get_boot_ns),		\
5566	FN(seq_printf),			\
5567	FN(seq_write),			\
5568	FN(sk_cgroup_id),		\
5569	FN(sk_ancestor_cgroup_id),	\
5570	FN(ringbuf_output),		\
5571	FN(ringbuf_reserve),		\
5572	FN(ringbuf_submit),		\
5573	FN(ringbuf_discard),		\
5574	FN(ringbuf_query),		\
5575	FN(csum_level),			\
5576	FN(skc_to_tcp6_sock),		\
5577	FN(skc_to_tcp_sock),		\
5578	FN(skc_to_tcp_timewait_sock),	\
5579	FN(skc_to_tcp_request_sock),	\
5580	FN(skc_to_udp6_sock),		\
5581	FN(get_task_stack),		\
5582	FN(load_hdr_opt),		\
5583	FN(store_hdr_opt),		\
5584	FN(reserve_hdr_opt),		\
5585	FN(inode_storage_get),		\
5586	FN(inode_storage_delete),	\
5587	FN(d_path),			\
5588	FN(copy_from_user),		\
5589	FN(snprintf_btf),		\
5590	FN(seq_printf_btf),		\
5591	FN(skb_cgroup_classid),		\
5592	FN(redirect_neigh),		\
5593	FN(per_cpu_ptr),		\
5594	FN(this_cpu_ptr),		\
5595	FN(redirect_peer),		\
5596	FN(task_storage_get),		\
5597	FN(task_storage_delete),	\
5598	FN(get_current_task_btf),	\
5599	FN(bprm_opts_set),		\
5600	FN(ktime_get_coarse_ns),	\
5601	FN(ima_inode_hash),		\
5602	FN(sock_from_file),		\
5603	FN(check_mtu),			\
5604	FN(for_each_map_elem),		\
5605	FN(snprintf),			\
5606	FN(sys_bpf),			\
5607	FN(btf_find_by_name_kind),	\
5608	FN(sys_close),			\
5609	FN(timer_init),			\
5610	FN(timer_set_callback),		\
5611	FN(timer_start),		\
5612	FN(timer_cancel),		\
5613	FN(get_func_ip),		\
5614	FN(get_attach_cookie),		\
5615	FN(task_pt_regs),		\
5616	FN(get_branch_snapshot),	\
5617	FN(trace_vprintk),		\
5618	FN(skc_to_unix_sock),		\
5619	FN(kallsyms_lookup_name),	\
5620	FN(find_vma),			\
5621	FN(loop),			\
5622	FN(strncmp),			\
5623	FN(get_func_arg),		\
5624	FN(get_func_ret),		\
5625	FN(get_func_arg_cnt),		\
5626	FN(get_retval),			\
5627	FN(set_retval),			\
5628	FN(xdp_get_buff_len),		\
5629	FN(xdp_load_bytes),		\
5630	FN(xdp_store_bytes),		\
5631	FN(copy_from_user_task),	\
5632	FN(skb_set_tstamp),		\
5633	FN(ima_file_hash),		\
5634	FN(kptr_xchg),			\
5635	FN(map_lookup_percpu_elem),     \
5636	FN(skc_to_mptcp_sock),		\
5637	FN(dynptr_from_mem),		\
5638	FN(ringbuf_reserve_dynptr),	\
5639	FN(ringbuf_submit_dynptr),	\
5640	FN(ringbuf_discard_dynptr),	\
5641	FN(dynptr_read),		\
5642	FN(dynptr_write),		\
5643	FN(dynptr_data),		\
5644	FN(tcp_raw_gen_syncookie_ipv4),	\
5645	FN(tcp_raw_gen_syncookie_ipv6),	\
5646	FN(tcp_raw_check_syncookie_ipv4),	\
5647	FN(tcp_raw_check_syncookie_ipv6),	\
5648	FN(ktime_get_tai_ns),		\
5649	FN(user_ringbuf_drain),		\
5650	/* */
5651
5652/* integer value in 'imm' field of BPF_CALL instruction selects which helper
5653 * function eBPF program intends to call
5654 */
5655#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5656enum bpf_func_id {
5657	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5658	__BPF_FUNC_MAX_ID,
5659};
5660#undef __BPF_ENUM_FN
5661
5662/* All flags used by eBPF helper functions, placed here. */
5663
5664/* BPF_FUNC_skb_store_bytes flags. */
5665enum {
5666	BPF_F_RECOMPUTE_CSUM		= (1ULL << 0),
5667	BPF_F_INVALIDATE_HASH		= (1ULL << 1),
5668};
5669
5670/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
5671 * First 4 bits are for passing the header field size.
5672 */
5673enum {
5674	BPF_F_HDR_FIELD_MASK		= 0xfULL,
5675};
5676
5677/* BPF_FUNC_l4_csum_replace flags. */
5678enum {
5679	BPF_F_PSEUDO_HDR		= (1ULL << 4),
5680	BPF_F_MARK_MANGLED_0		= (1ULL << 5),
5681	BPF_F_MARK_ENFORCE		= (1ULL << 6),
5682};
5683
5684/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
5685enum {
5686	BPF_F_INGRESS			= (1ULL << 0),
5687};
5688
5689/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
5690enum {
5691	BPF_F_TUNINFO_IPV6		= (1ULL << 0),
5692};
5693
5694/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
5695enum {
5696	BPF_F_SKIP_FIELD_MASK		= 0xffULL,
5697	BPF_F_USER_STACK		= (1ULL << 8),
5698/* flags used by BPF_FUNC_get_stackid only. */
5699	BPF_F_FAST_STACK_CMP		= (1ULL << 9),
5700	BPF_F_REUSE_STACKID		= (1ULL << 10),
5701/* flags used by BPF_FUNC_get_stack only. */
5702	BPF_F_USER_BUILD_ID		= (1ULL << 11),
5703};
5704
5705/* BPF_FUNC_skb_set_tunnel_key flags. */
5706enum {
5707	BPF_F_ZERO_CSUM_TX		= (1ULL << 1),
5708	BPF_F_DONT_FRAGMENT		= (1ULL << 2),
5709	BPF_F_SEQ_NUMBER		= (1ULL << 3),
5710};
5711
5712/* BPF_FUNC_skb_get_tunnel_key flags. */
5713enum {
5714	BPF_F_TUNINFO_FLAGS		= (1ULL << 4),
5715};
5716
5717/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
5718 * BPF_FUNC_perf_event_read_value flags.
5719 */
5720enum {
5721	BPF_F_INDEX_MASK		= 0xffffffffULL,
5722	BPF_F_CURRENT_CPU		= BPF_F_INDEX_MASK,
5723/* BPF_FUNC_perf_event_output for sk_buff input context. */
5724	BPF_F_CTXLEN_MASK		= (0xfffffULL << 32),
5725};
5726
5727/* Current network namespace */
5728enum {
5729	BPF_F_CURRENT_NETNS		= (-1L),
5730};
5731
5732/* BPF_FUNC_csum_level level values. */
5733enum {
5734	BPF_CSUM_LEVEL_QUERY,
5735	BPF_CSUM_LEVEL_INC,
5736	BPF_CSUM_LEVEL_DEC,
5737	BPF_CSUM_LEVEL_RESET,
5738};
5739
5740/* BPF_FUNC_skb_adjust_room flags. */
5741enum {
5742	BPF_F_ADJ_ROOM_FIXED_GSO	= (1ULL << 0),
5743	BPF_F_ADJ_ROOM_ENCAP_L3_IPV4	= (1ULL << 1),
5744	BPF_F_ADJ_ROOM_ENCAP_L3_IPV6	= (1ULL << 2),
5745	BPF_F_ADJ_ROOM_ENCAP_L4_GRE	= (1ULL << 3),
5746	BPF_F_ADJ_ROOM_ENCAP_L4_UDP	= (1ULL << 4),
5747	BPF_F_ADJ_ROOM_NO_CSUM_RESET	= (1ULL << 5),
5748	BPF_F_ADJ_ROOM_ENCAP_L2_ETH	= (1ULL << 6),
5749};
5750
5751enum {
5752	BPF_ADJ_ROOM_ENCAP_L2_MASK	= 0xff,
5753	BPF_ADJ_ROOM_ENCAP_L2_SHIFT	= 56,
5754};
5755
5756#define BPF_F_ADJ_ROOM_ENCAP_L2(len)	(((__u64)len & \
5757					  BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5758					 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5759
5760/* BPF_FUNC_sysctl_get_name flags. */
5761enum {
5762	BPF_F_SYSCTL_BASE_NAME		= (1ULL << 0),
5763};
5764
5765/* BPF_FUNC_<kernel_obj>_storage_get flags */
5766enum {
5767	BPF_LOCAL_STORAGE_GET_F_CREATE	= (1ULL << 0),
5768	/* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
5769	 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5770	 */
5771	BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
5772};
5773
5774/* BPF_FUNC_read_branch_records flags. */
5775enum {
5776	BPF_F_GET_BRANCH_RECORDS_SIZE	= (1ULL << 0),
5777};
5778
5779/* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
5780 * BPF_FUNC_bpf_ringbuf_output flags.
5781 */
5782enum {
5783	BPF_RB_NO_WAKEUP		= (1ULL << 0),
5784	BPF_RB_FORCE_WAKEUP		= (1ULL << 1),
5785};
5786
5787/* BPF_FUNC_bpf_ringbuf_query flags */
5788enum {
5789	BPF_RB_AVAIL_DATA = 0,
5790	BPF_RB_RING_SIZE = 1,
5791	BPF_RB_CONS_POS = 2,
5792	BPF_RB_PROD_POS = 3,
5793};
5794
5795/* BPF ring buffer constants */
5796enum {
5797	BPF_RINGBUF_BUSY_BIT		= (1U << 31),
5798	BPF_RINGBUF_DISCARD_BIT		= (1U << 30),
5799	BPF_RINGBUF_HDR_SZ		= 8,
5800};
5801
5802/* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
5803enum {
5804	BPF_SK_LOOKUP_F_REPLACE		= (1ULL << 0),
5805	BPF_SK_LOOKUP_F_NO_REUSEPORT	= (1ULL << 1),
5806};
5807
5808/* Mode for BPF_FUNC_skb_adjust_room helper. */
5809enum bpf_adj_room_mode {
5810	BPF_ADJ_ROOM_NET,
5811	BPF_ADJ_ROOM_MAC,
5812};
5813
5814/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
5815enum bpf_hdr_start_off {
5816	BPF_HDR_START_MAC,
5817	BPF_HDR_START_NET,
5818};
5819
5820/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
5821enum bpf_lwt_encap_mode {
5822	BPF_LWT_ENCAP_SEG6,
5823	BPF_LWT_ENCAP_SEG6_INLINE,
5824	BPF_LWT_ENCAP_IP,
5825};
5826
5827/* Flags for bpf_bprm_opts_set helper */
5828enum {
5829	BPF_F_BPRM_SECUREEXEC	= (1ULL << 0),
5830};
5831
5832/* Flags for bpf_redirect_map helper */
5833enum {
5834	BPF_F_BROADCAST		= (1ULL << 3),
5835	BPF_F_EXCLUDE_INGRESS	= (1ULL << 4),
5836};
5837
5838#define __bpf_md_ptr(type, name)	\
5839union {					\
5840	type name;			\
5841	__u64 :64;			\
5842} __attribute__((aligned(8)))
5843
5844enum {
5845	BPF_SKB_TSTAMP_UNSPEC,
5846	BPF_SKB_TSTAMP_DELIVERY_MONO,	/* tstamp has mono delivery time */
5847	/* For any BPF_SKB_TSTAMP_* that the bpf prog cannot handle,
5848	 * the bpf prog should handle it like BPF_SKB_TSTAMP_UNSPEC
5849	 * and try to deduce it by ingress, egress or skb->sk->sk_clockid.
5850	 */
5851};
5852
5853/* user accessible mirror of in-kernel sk_buff.
5854 * new fields can only be added to the end of this structure
5855 */
5856struct __sk_buff {
5857	__u32 len;
5858	__u32 pkt_type;
5859	__u32 mark;
5860	__u32 queue_mapping;
5861	__u32 protocol;
5862	__u32 vlan_present;
5863	__u32 vlan_tci;
5864	__u32 vlan_proto;
5865	__u32 priority;
5866	__u32 ingress_ifindex;
5867	__u32 ifindex;
5868	__u32 tc_index;
5869	__u32 cb[5];
5870	__u32 hash;
5871	__u32 tc_classid;
5872	__u32 data;
5873	__u32 data_end;
5874	__u32 napi_id;
5875
5876	/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
5877	__u32 family;
5878	__u32 remote_ip4;	/* Stored in network byte order */
5879	__u32 local_ip4;	/* Stored in network byte order */
5880	__u32 remote_ip6[4];	/* Stored in network byte order */
5881	__u32 local_ip6[4];	/* Stored in network byte order */
5882	__u32 remote_port;	/* Stored in network byte order */
5883	__u32 local_port;	/* stored in host byte order */
5884	/* ... here. */
5885
5886	__u32 data_meta;
5887	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5888	__u64 tstamp;
5889	__u32 wire_len;
5890	__u32 gso_segs;
5891	__bpf_md_ptr(struct bpf_sock *, sk);
5892	__u32 gso_size;
5893	__u8  tstamp_type;
5894	__u32 :24;		/* Padding, future use. */
5895	__u64 hwtstamp;
5896};
5897
5898struct bpf_tunnel_key {
5899	__u32 tunnel_id;
5900	union {
5901		__u32 remote_ipv4;
5902		__u32 remote_ipv6[4];
5903	};
5904	__u8 tunnel_tos;
5905	__u8 tunnel_ttl;
5906	union {
5907		__u16 tunnel_ext;	/* compat */
5908		__be16 tunnel_flags;
5909	};
5910	__u32 tunnel_label;
5911	union {
5912		__u32 local_ipv4;
5913		__u32 local_ipv6[4];
5914	};
5915};
5916
5917/* user accessible mirror of in-kernel xfrm_state.
5918 * new fields can only be added to the end of this structure
5919 */
5920struct bpf_xfrm_state {
5921	__u32 reqid;
5922	__u32 spi;	/* Stored in network byte order */
5923	__u16 family;
5924	__u16 ext;	/* Padding, future use. */
5925	union {
5926		__u32 remote_ipv4;	/* Stored in network byte order */
5927		__u32 remote_ipv6[4];	/* Stored in network byte order */
5928	};
5929};
5930
5931/* Generic BPF return codes which all BPF program types may support.
5932 * The values are binary compatible with their TC_ACT_* counter-part to
5933 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5934 * programs.
5935 *
5936 * XDP is handled seprately, see XDP_*.
5937 */
5938enum bpf_ret_code {
5939	BPF_OK = 0,
5940	/* 1 reserved */
5941	BPF_DROP = 2,
5942	/* 3-6 reserved */
5943	BPF_REDIRECT = 7,
5944	/* >127 are reserved for prog type specific return codes.
5945	 *
5946	 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5947	 *    BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5948	 *    changed and should be routed based on its new L3 header.
5949	 *    (This is an L3 redirect, as opposed to L2 redirect
5950	 *    represented by BPF_REDIRECT above).
5951	 */
5952	BPF_LWT_REROUTE = 128,
5953	/* BPF_FLOW_DISSECTOR_CONTINUE: used by BPF_PROG_TYPE_FLOW_DISSECTOR
5954	 *   to indicate that no custom dissection was performed, and
5955	 *   fallback to standard dissector is requested.
5956	 */
5957	BPF_FLOW_DISSECTOR_CONTINUE = 129,
5958};
5959
5960struct bpf_sock {
5961	__u32 bound_dev_if;
5962	__u32 family;
5963	__u32 type;
5964	__u32 protocol;
5965	__u32 mark;
5966	__u32 priority;
5967	/* IP address also allows 1 and 2 bytes access */
5968	__u32 src_ip4;
5969	__u32 src_ip6[4];
5970	__u32 src_port;		/* host byte order */
5971	__be16 dst_port;	/* network byte order */
5972	__u16 :16;		/* zero padding */
5973	__u32 dst_ip4;
5974	__u32 dst_ip6[4];
5975	__u32 state;
5976	__s32 rx_queue_mapping;
5977};
5978
5979struct bpf_tcp_sock {
5980	__u32 snd_cwnd;		/* Sending congestion window		*/
5981	__u32 srtt_us;		/* smoothed round trip time << 3 in usecs */
5982	__u32 rtt_min;
5983	__u32 snd_ssthresh;	/* Slow start size threshold		*/
5984	__u32 rcv_nxt;		/* What we want to receive next		*/
5985	__u32 snd_nxt;		/* Next sequence we send		*/
5986	__u32 snd_una;		/* First byte we want an ack for	*/
5987	__u32 mss_cache;	/* Cached effective mss, not including SACKS */
5988	__u32 ecn_flags;	/* ECN status bits.			*/
5989	__u32 rate_delivered;	/* saved rate sample: packets delivered */
5990	__u32 rate_interval_us;	/* saved rate sample: time elapsed */
5991	__u32 packets_out;	/* Packets which are "in flight"	*/
5992	__u32 retrans_out;	/* Retransmitted packets out		*/
5993	__u32 total_retrans;	/* Total retransmits for entire connection */
5994	__u32 segs_in;		/* RFC4898 tcpEStatsPerfSegsIn
5995				 * total number of segments in.
5996				 */
5997	__u32 data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
5998				 * total number of data segments in.
5999				 */
6000	__u32 segs_out;		/* RFC4898 tcpEStatsPerfSegsOut
6001				 * The total number of segments sent.
6002				 */
6003	__u32 data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
6004				 * total number of data segments sent.
6005				 */
6006	__u32 lost_out;		/* Lost packets			*/
6007	__u32 sacked_out;	/* SACK'd packets			*/
6008	__u64 bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
6009				 * sum(delta(rcv_nxt)), or how many bytes
6010				 * were acked.
6011				 */
6012	__u64 bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
6013				 * sum(delta(snd_una)), or how many bytes
6014				 * were acked.
6015				 */
6016	__u32 dsack_dups;	/* RFC4898 tcpEStatsStackDSACKDups
6017				 * total number of DSACK blocks received
6018				 */
6019	__u32 delivered;	/* Total data packets delivered incl. rexmits */
6020	__u32 delivered_ce;	/* Like the above but only ECE marked packets */
6021	__u32 icsk_retransmits;	/* Number of unrecovered [RTO] timeouts */
6022};
6023
6024struct bpf_sock_tuple {
6025	union {
6026		struct {
6027			__be32 saddr;
6028			__be32 daddr;
6029			__be16 sport;
6030			__be16 dport;
6031		} ipv4;
6032		struct {
6033			__be32 saddr[4];
6034			__be32 daddr[4];
6035			__be16 sport;
6036			__be16 dport;
6037		} ipv6;
6038	};
6039};
6040
6041struct bpf_xdp_sock {
6042	__u32 queue_id;
6043};
6044
6045#define XDP_PACKET_HEADROOM 256
6046
6047/* User return codes for XDP prog type.
6048 * A valid XDP program must return one of these defined values. All other
6049 * return codes are reserved for future use. Unknown return codes will
6050 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
6051 */
6052enum xdp_action {
6053	XDP_ABORTED = 0,
6054	XDP_DROP,
6055	XDP_PASS,
6056	XDP_TX,
6057	XDP_REDIRECT,
6058};
6059
6060/* user accessible metadata for XDP packet hook
6061 * new fields must be added to the end of this structure
6062 */
6063struct xdp_md {
6064	__u32 data;
6065	__u32 data_end;
6066	__u32 data_meta;
6067	/* Below access go through struct xdp_rxq_info */
6068	__u32 ingress_ifindex; /* rxq->dev->ifindex */
6069	__u32 rx_queue_index;  /* rxq->queue_index  */
6070
6071	__u32 egress_ifindex;  /* txq->dev->ifindex */
6072};
6073
6074/* DEVMAP map-value layout
6075 *
6076 * The struct data-layout of map-value is a configuration interface.
6077 * New members can only be added to the end of this structure.
6078 */
6079struct bpf_devmap_val {
6080	__u32 ifindex;   /* device index */
6081	union {
6082		int   fd;  /* prog fd on map write */
6083		__u32 id;  /* prog id on map read */
6084	} bpf_prog;
6085};
6086
6087/* CPUMAP map-value layout
6088 *
6089 * The struct data-layout of map-value is a configuration interface.
6090 * New members can only be added to the end of this structure.
6091 */
6092struct bpf_cpumap_val {
6093	__u32 qsize;	/* queue size to remote target CPU */
6094	union {
6095		int   fd;	/* prog fd on map write */
6096		__u32 id;	/* prog id on map read */
6097	} bpf_prog;
6098};
6099
6100enum sk_action {
6101	SK_DROP = 0,
6102	SK_PASS,
6103};
6104
6105/* user accessible metadata for SK_MSG packet hook, new fields must
6106 * be added to the end of this structure
6107 */
6108struct sk_msg_md {
6109	__bpf_md_ptr(void *, data);
6110	__bpf_md_ptr(void *, data_end);
6111
6112	__u32 family;
6113	__u32 remote_ip4;	/* Stored in network byte order */
6114	__u32 local_ip4;	/* Stored in network byte order */
6115	__u32 remote_ip6[4];	/* Stored in network byte order */
6116	__u32 local_ip6[4];	/* Stored in network byte order */
6117	__u32 remote_port;	/* Stored in network byte order */
6118	__u32 local_port;	/* stored in host byte order */
6119	__u32 size;		/* Total size of sk_msg */
6120
6121	__bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
6122};
6123
6124struct sk_reuseport_md {
6125	/*
6126	 * Start of directly accessible data. It begins from
6127	 * the tcp/udp header.
6128	 */
6129	__bpf_md_ptr(void *, data);
6130	/* End of directly accessible data */
6131	__bpf_md_ptr(void *, data_end);
6132	/*
6133	 * Total length of packet (starting from the tcp/udp header).
6134	 * Note that the directly accessible bytes (data_end - data)
6135	 * could be less than this "len".  Those bytes could be
6136	 * indirectly read by a helper "bpf_skb_load_bytes()".
6137	 */
6138	__u32 len;
6139	/*
6140	 * Eth protocol in the mac header (network byte order). e.g.
6141	 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
6142	 */
6143	__u32 eth_protocol;
6144	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
6145	__u32 bind_inany;	/* Is sock bound to an INANY address? */
6146	__u32 hash;		/* A hash of the packet 4 tuples */
6147	/* When reuse->migrating_sk is NULL, it is selecting a sk for the
6148	 * new incoming connection request (e.g. selecting a listen sk for
6149	 * the received SYN in the TCP case).  reuse->sk is one of the sk
6150	 * in the reuseport group. The bpf prog can use reuse->sk to learn
6151	 * the local listening ip/port without looking into the skb.
6152	 *
6153	 * When reuse->migrating_sk is not NULL, reuse->sk is closed and
6154	 * reuse->migrating_sk is the socket that needs to be migrated
6155	 * to another listening socket.  migrating_sk could be a fullsock
6156	 * sk that is fully established or a reqsk that is in-the-middle
6157	 * of 3-way handshake.
6158	 */
6159	__bpf_md_ptr(struct bpf_sock *, sk);
6160	__bpf_md_ptr(struct bpf_sock *, migrating_sk);
6161};
6162
6163#define BPF_TAG_SIZE	8
6164
6165struct bpf_prog_info {
6166	__u32 type;
6167	__u32 id;
6168	__u8  tag[BPF_TAG_SIZE];
6169	__u32 jited_prog_len;
6170	__u32 xlated_prog_len;
6171	__aligned_u64 jited_prog_insns;
6172	__aligned_u64 xlated_prog_insns;
6173	__u64 load_time;	/* ns since boottime */
6174	__u32 created_by_uid;
6175	__u32 nr_map_ids;
6176	__aligned_u64 map_ids;
6177	char name[BPF_OBJ_NAME_LEN];
6178	__u32 ifindex;
6179	__u32 gpl_compatible:1;
6180	__u32 :31; /* alignment pad */
6181	__u64 netns_dev;
6182	__u64 netns_ino;
6183	__u32 nr_jited_ksyms;
6184	__u32 nr_jited_func_lens;
6185	__aligned_u64 jited_ksyms;
6186	__aligned_u64 jited_func_lens;
6187	__u32 btf_id;
6188	__u32 func_info_rec_size;
6189	__aligned_u64 func_info;
6190	__u32 nr_func_info;
6191	__u32 nr_line_info;
6192	__aligned_u64 line_info;
6193	__aligned_u64 jited_line_info;
6194	__u32 nr_jited_line_info;
6195	__u32 line_info_rec_size;
6196	__u32 jited_line_info_rec_size;
6197	__u32 nr_prog_tags;
6198	__aligned_u64 prog_tags;
6199	__u64 run_time_ns;
6200	__u64 run_cnt;
6201	__u64 recursion_misses;
6202	__u32 verified_insns;
6203	__u32 attach_btf_obj_id;
6204	__u32 attach_btf_id;
6205} __attribute__((aligned(8)));
6206
6207struct bpf_map_info {
6208	__u32 type;
6209	__u32 id;
6210	__u32 key_size;
6211	__u32 value_size;
6212	__u32 max_entries;
6213	__u32 map_flags;
6214	char  name[BPF_OBJ_NAME_LEN];
6215	__u32 ifindex;
6216	__u32 btf_vmlinux_value_type_id;
6217	__u64 netns_dev;
6218	__u64 netns_ino;
6219	__u32 btf_id;
6220	__u32 btf_key_type_id;
6221	__u32 btf_value_type_id;
6222	__u32 :32;	/* alignment pad */
6223	__u64 map_extra;
6224} __attribute__((aligned(8)));
6225
6226struct bpf_btf_info {
6227	__aligned_u64 btf;
6228	__u32 btf_size;
6229	__u32 id;
6230	__aligned_u64 name;
6231	__u32 name_len;
6232	__u32 kernel_btf;
6233} __attribute__((aligned(8)));
6234
6235struct bpf_link_info {
6236	__u32 type;
6237	__u32 id;
6238	__u32 prog_id;
6239	union {
6240		struct {
6241			__aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
6242			__u32 tp_name_len;     /* in/out: tp_name buffer len */
6243		} raw_tracepoint;
6244		struct {
6245			__u32 attach_type;
6246			__u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */
6247			__u32 target_btf_id; /* BTF type id inside the object */
6248		} tracing;
6249		struct {
6250			__u64 cgroup_id;
6251			__u32 attach_type;
6252		} cgroup;
6253		struct {
6254			__aligned_u64 target_name; /* in/out: target_name buffer ptr */
6255			__u32 target_name_len;	   /* in/out: target_name buffer len */
6256
6257			/* If the iter specific field is 32 bits, it can be put
6258			 * in the first or second union. Otherwise it should be
6259			 * put in the second union.
6260			 */
6261			union {
6262				struct {
6263					__u32 map_id;
6264				} map;
6265			};
6266			union {
6267				struct {
6268					__u64 cgroup_id;
6269					__u32 order;
6270				} cgroup;
6271				struct {
6272					__u32 tid;
6273					__u32 pid;
6274				} task;
6275			};
6276		} iter;
6277		struct  {
6278			__u32 netns_ino;
6279			__u32 attach_type;
6280		} netns;
6281		struct {
6282			__u32 ifindex;
6283		} xdp;
6284	};
6285} __attribute__((aligned(8)));
6286
6287/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
6288 * by user and intended to be used by socket (e.g. to bind to, depends on
6289 * attach type).
6290 */
6291struct bpf_sock_addr {
6292	__u32 user_family;	/* Allows 4-byte read, but no write. */
6293	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.
6294				 * Stored in network byte order.
6295				 */
6296	__u32 user_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
6297				 * Stored in network byte order.
6298				 */
6299	__u32 user_port;	/* Allows 1,2,4-byte read and 4-byte write.
6300				 * Stored in network byte order
6301				 */
6302	__u32 family;		/* Allows 4-byte read, but no write */
6303	__u32 type;		/* Allows 4-byte read, but no write */
6304	__u32 protocol;		/* Allows 4-byte read, but no write */
6305	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read and 4-byte write.
6306				 * Stored in network byte order.
6307				 */
6308	__u32 msg_src_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
6309				 * Stored in network byte order.
6310				 */
6311	__bpf_md_ptr(struct bpf_sock *, sk);
6312};
6313
6314/* User bpf_sock_ops struct to access socket values and specify request ops
6315 * and their replies.
6316 * Some of this fields are in network (bigendian) byte order and may need
6317 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
6318 * New fields can only be added at the end of this structure
6319 */
6320struct bpf_sock_ops {
6321	__u32 op;
6322	union {
6323		__u32 args[4];		/* Optionally passed to bpf program */
6324		__u32 reply;		/* Returned by bpf program	    */
6325		__u32 replylong[4];	/* Optionally returned by bpf prog  */
6326	};
6327	__u32 family;
6328	__u32 remote_ip4;	/* Stored in network byte order */
6329	__u32 local_ip4;	/* Stored in network byte order */
6330	__u32 remote_ip6[4];	/* Stored in network byte order */
6331	__u32 local_ip6[4];	/* Stored in network byte order */
6332	__u32 remote_port;	/* Stored in network byte order */
6333	__u32 local_port;	/* stored in host byte order */
6334	__u32 is_fullsock;	/* Some TCP fields are only valid if
6335				 * there is a full socket. If not, the
6336				 * fields read as zero.
6337				 */
6338	__u32 snd_cwnd;
6339	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
6340	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
6341	__u32 state;
6342	__u32 rtt_min;
6343	__u32 snd_ssthresh;
6344	__u32 rcv_nxt;
6345	__u32 snd_nxt;
6346	__u32 snd_una;
6347	__u32 mss_cache;
6348	__u32 ecn_flags;
6349	__u32 rate_delivered;
6350	__u32 rate_interval_us;
6351	__u32 packets_out;
6352	__u32 retrans_out;
6353	__u32 total_retrans;
6354	__u32 segs_in;
6355	__u32 data_segs_in;
6356	__u32 segs_out;
6357	__u32 data_segs_out;
6358	__u32 lost_out;
6359	__u32 sacked_out;
6360	__u32 sk_txhash;
6361	__u64 bytes_received;
6362	__u64 bytes_acked;
6363	__bpf_md_ptr(struct bpf_sock *, sk);
6364	/* [skb_data, skb_data_end) covers the whole TCP header.
6365	 *
6366	 * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
6367	 * BPF_SOCK_OPS_HDR_OPT_LEN_CB:   Not useful because the
6368	 *                                header has not been written.
6369	 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
6370	 *				  been written so far.
6371	 * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:  The SYNACK that concludes
6372	 *					the 3WHS.
6373	 * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
6374	 *					the 3WHS.
6375	 *
6376	 * bpf_load_hdr_opt() can also be used to read a particular option.
6377	 */
6378	__bpf_md_ptr(void *, skb_data);
6379	__bpf_md_ptr(void *, skb_data_end);
6380	__u32 skb_len;		/* The total length of a packet.
6381				 * It includes the header, options,
6382				 * and payload.
6383				 */
6384	__u32 skb_tcp_flags;	/* tcp_flags of the header.  It provides
6385				 * an easy way to check for tcp_flags
6386				 * without parsing skb_data.
6387				 *
6388				 * In particular, the skb_tcp_flags
6389				 * will still be available in
6390				 * BPF_SOCK_OPS_HDR_OPT_LEN even though
6391				 * the outgoing header has not
6392				 * been written yet.
6393				 */
6394};
6395
6396/* Definitions for bpf_sock_ops_cb_flags */
6397enum {
6398	BPF_SOCK_OPS_RTO_CB_FLAG	= (1<<0),
6399	BPF_SOCK_OPS_RETRANS_CB_FLAG	= (1<<1),
6400	BPF_SOCK_OPS_STATE_CB_FLAG	= (1<<2),
6401	BPF_SOCK_OPS_RTT_CB_FLAG	= (1<<3),
6402	/* Call bpf for all received TCP headers.  The bpf prog will be
6403	 * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6404	 *
6405	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6406	 * for the header option related helpers that will be useful
6407	 * to the bpf programs.
6408	 *
6409	 * It could be used at the client/active side (i.e. connect() side)
6410	 * when the server told it that the server was in syncookie
6411	 * mode and required the active side to resend the bpf-written
6412	 * options.  The active side can keep writing the bpf-options until
6413	 * it received a valid packet from the server side to confirm
6414	 * the earlier packet (and options) has been received.  The later
6415	 * example patch is using it like this at the active side when the
6416	 * server is in syncookie mode.
6417	 *
6418	 * The bpf prog will usually turn this off in the common cases.
6419	 */
6420	BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG	= (1<<4),
6421	/* Call bpf when kernel has received a header option that
6422	 * the kernel cannot handle.  The bpf prog will be called under
6423	 * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
6424	 *
6425	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6426	 * for the header option related helpers that will be useful
6427	 * to the bpf programs.
6428	 */
6429	BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
6430	/* Call bpf when the kernel is writing header options for the
6431	 * outgoing packet.  The bpf prog will first be called
6432	 * to reserve space in a skb under
6433	 * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB.  Then
6434	 * the bpf prog will be called to write the header option(s)
6435	 * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6436	 *
6437	 * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
6438	 * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
6439	 * related helpers that will be useful to the bpf programs.
6440	 *
6441	 * The kernel gets its chance to reserve space and write
6442	 * options first before the BPF program does.
6443	 */
6444	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
6445/* Mask of all currently supported cb flags */
6446	BPF_SOCK_OPS_ALL_CB_FLAGS       = 0x7F,
6447};
6448
6449/* List of known BPF sock_ops operators.
6450 * New entries can only be added at the end
6451 */
6452enum {
6453	BPF_SOCK_OPS_VOID,
6454	BPF_SOCK_OPS_TIMEOUT_INIT,	/* Should return SYN-RTO value to use or
6455					 * -1 if default value should be used
6456					 */
6457	BPF_SOCK_OPS_RWND_INIT,		/* Should return initial advertized
6458					 * window (in packets) or -1 if default
6459					 * value should be used
6460					 */
6461	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
6462					 * active connection is initialized
6463					 */
6464	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
6465						 * active connection is
6466						 * established
6467						 */
6468	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
6469						 * passive connection is
6470						 * established
6471						 */
6472	BPF_SOCK_OPS_NEEDS_ECN,		/* If connection's congestion control
6473					 * needs ECN
6474					 */
6475	BPF_SOCK_OPS_BASE_RTT,		/* Get base RTT. The correct value is
6476					 * based on the path and may be
6477					 * dependent on the congestion control
6478					 * algorithm. In general it indicates
6479					 * a congestion threshold. RTTs above
6480					 * this indicate congestion
6481					 */
6482	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
6483					 * Arg1: value of icsk_retransmits
6484					 * Arg2: value of icsk_rto
6485					 * Arg3: whether RTO has expired
6486					 */
6487	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
6488					 * Arg1: sequence number of 1st byte
6489					 * Arg2: # segments
6490					 * Arg3: return value of
6491					 *       tcp_transmit_skb (0 => success)
6492					 */
6493	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
6494					 * Arg1: old_state
6495					 * Arg2: new_state
6496					 */
6497	BPF_SOCK_OPS_TCP_LISTEN_CB,	/* Called on listen(2), right after
6498					 * socket transition to LISTEN state.
6499					 */
6500	BPF_SOCK_OPS_RTT_CB,		/* Called on every RTT.
6501					 */
6502	BPF_SOCK_OPS_PARSE_HDR_OPT_CB,	/* Parse the header option.
6503					 * It will be called to handle
6504					 * the packets received at
6505					 * an already established
6506					 * connection.
6507					 *
6508					 * sock_ops->skb_data:
6509					 * Referring to the received skb.
6510					 * It covers the TCP header only.
6511					 *
6512					 * bpf_load_hdr_opt() can also
6513					 * be used to search for a
6514					 * particular option.
6515					 */
6516	BPF_SOCK_OPS_HDR_OPT_LEN_CB,	/* Reserve space for writing the
6517					 * header option later in
6518					 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6519					 * Arg1: bool want_cookie. (in
6520					 *       writing SYNACK only)
6521					 *
6522					 * sock_ops->skb_data:
6523					 * Not available because no header has
6524					 * been	written yet.
6525					 *
6526					 * sock_ops->skb_tcp_flags:
6527					 * The tcp_flags of the
6528					 * outgoing skb. (e.g. SYN, ACK, FIN).
6529					 *
6530					 * bpf_reserve_hdr_opt() should
6531					 * be used to reserve space.
6532					 */
6533	BPF_SOCK_OPS_WRITE_HDR_OPT_CB,	/* Write the header options
6534					 * Arg1: bool want_cookie. (in
6535					 *       writing SYNACK only)
6536					 *
6537					 * sock_ops->skb_data:
6538					 * Referring to the outgoing skb.
6539					 * It covers the TCP header
6540					 * that has already been written
6541					 * by the kernel and the
6542					 * earlier bpf-progs.
6543					 *
6544					 * sock_ops->skb_tcp_flags:
6545					 * The tcp_flags of the outgoing
6546					 * skb. (e.g. SYN, ACK, FIN).
6547					 *
6548					 * bpf_store_hdr_opt() should
6549					 * be used to write the
6550					 * option.
6551					 *
6552					 * bpf_load_hdr_opt() can also
6553					 * be used to search for a
6554					 * particular option that
6555					 * has already been written
6556					 * by the kernel or the
6557					 * earlier bpf-progs.
6558					 */
6559};
6560
6561/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
6562 * changes between the TCP and BPF versions. Ideally this should never happen.
6563 * If it does, we need to add code to convert them before calling
6564 * the BPF sock_ops function.
6565 */
6566enum {
6567	BPF_TCP_ESTABLISHED = 1,
6568	BPF_TCP_SYN_SENT,
6569	BPF_TCP_SYN_RECV,
6570	BPF_TCP_FIN_WAIT1,
6571	BPF_TCP_FIN_WAIT2,
6572	BPF_TCP_TIME_WAIT,
6573	BPF_TCP_CLOSE,
6574	BPF_TCP_CLOSE_WAIT,
6575	BPF_TCP_LAST_ACK,
6576	BPF_TCP_LISTEN,
6577	BPF_TCP_CLOSING,	/* Now a valid state */
6578	BPF_TCP_NEW_SYN_RECV,
6579
6580	BPF_TCP_MAX_STATES	/* Leave at the end! */
6581};
6582
6583enum {
6584	TCP_BPF_IW		= 1001,	/* Set TCP initial congestion window */
6585	TCP_BPF_SNDCWND_CLAMP	= 1002,	/* Set sndcwnd_clamp */
6586	TCP_BPF_DELACK_MAX	= 1003, /* Max delay ack in usecs */
6587	TCP_BPF_RTO_MIN		= 1004, /* Min delay ack in usecs */
6588	/* Copy the SYN pkt to optval
6589	 *
6590	 * BPF_PROG_TYPE_SOCK_OPS only.  It is similar to the
6591	 * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
6592	 * to only getting from the saved_syn.  It can either get the
6593	 * syn packet from:
6594	 *
6595	 * 1. the just-received SYN packet (only available when writing the
6596	 *    SYNACK).  It will be useful when it is not necessary to
6597	 *    save the SYN packet for latter use.  It is also the only way
6598	 *    to get the SYN during syncookie mode because the syn
6599	 *    packet cannot be saved during syncookie.
6600	 *
6601	 * OR
6602	 *
6603	 * 2. the earlier saved syn which was done by
6604	 *    bpf_setsockopt(TCP_SAVE_SYN).
6605	 *
6606	 * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
6607	 * SYN packet is obtained.
6608	 *
6609	 * If the bpf-prog does not need the IP[46] header,  the
6610	 * bpf-prog can avoid parsing the IP header by using
6611	 * TCP_BPF_SYN.  Otherwise, the bpf-prog can get both
6612	 * IP[46] and TCP header by using TCP_BPF_SYN_IP.
6613	 *
6614	 *      >0: Total number of bytes copied
6615	 * -ENOSPC: Not enough space in optval. Only optlen number of
6616	 *          bytes is copied.
6617	 * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
6618	 *	    is not saved by setsockopt(TCP_SAVE_SYN).
6619	 */
6620	TCP_BPF_SYN		= 1005, /* Copy the TCP header */
6621	TCP_BPF_SYN_IP		= 1006, /* Copy the IP[46] and TCP header */
6622	TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
6623};
6624
6625enum {
6626	BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
6627};
6628
6629/* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
6630 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6631 */
6632enum {
6633	BPF_WRITE_HDR_TCP_CURRENT_MSS = 1,	/* Kernel is finding the
6634						 * total option spaces
6635						 * required for an established
6636						 * sk in order to calculate the
6637						 * MSS.  No skb is actually
6638						 * sent.
6639						 */
6640	BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2,	/* Kernel is in syncookie mode
6641						 * when sending a SYN.
6642						 */
6643};
6644
6645struct bpf_perf_event_value {
6646	__u64 counter;
6647	__u64 enabled;
6648	__u64 running;
6649};
6650
6651enum {
6652	BPF_DEVCG_ACC_MKNOD	= (1ULL << 0),
6653	BPF_DEVCG_ACC_READ	= (1ULL << 1),
6654	BPF_DEVCG_ACC_WRITE	= (1ULL << 2),
6655};
6656
6657enum {
6658	BPF_DEVCG_DEV_BLOCK	= (1ULL << 0),
6659	BPF_DEVCG_DEV_CHAR	= (1ULL << 1),
6660};
6661
6662struct bpf_cgroup_dev_ctx {
6663	/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
6664	__u32 access_type;
6665	__u32 major;
6666	__u32 minor;
6667};
6668
6669struct bpf_raw_tracepoint_args {
6670	__u64 args[0];
6671};
6672
6673/* DIRECT:  Skip the FIB rules and go to FIB table associated with device
6674 * OUTPUT:  Do lookup from egress perspective; default is ingress
6675 */
6676enum {
6677	BPF_FIB_LOOKUP_DIRECT  = (1U << 0),
6678	BPF_FIB_LOOKUP_OUTPUT  = (1U << 1),
6679};
6680
6681enum {
6682	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
6683	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
6684	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
6685	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
6686	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
6687	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
6688	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
6689	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
6690	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6691};
6692
6693struct bpf_fib_lookup {
6694	/* input:  network family for lookup (AF_INET, AF_INET6)
6695	 * output: network family of egress nexthop
6696	 */
6697	__u8	family;
6698
6699	/* set if lookup is to consider L4 data - e.g., FIB rules */
6700	__u8	l4_protocol;
6701	__be16	sport;
6702	__be16	dport;
6703
6704	union {	/* used for MTU check */
6705		/* input to lookup */
6706		__u16	tot_len; /* L3 length from network hdr (iph->tot_len) */
6707
6708		/* output: MTU value */
6709		__u16	mtu_result;
6710	};
6711	/* input: L3 device index for lookup
6712	 * output: device index from FIB lookup
6713	 */
6714	__u32	ifindex;
6715
6716	union {
6717		/* inputs to lookup */
6718		__u8	tos;		/* AF_INET  */
6719		__be32	flowinfo;	/* AF_INET6, flow_label + priority */
6720
6721		/* output: metric of fib result (IPv4/IPv6 only) */
6722		__u32	rt_metric;
6723	};
6724
6725	union {
6726		__be32		ipv4_src;
6727		__u32		ipv6_src[4];  /* in6_addr; network order */
6728	};
6729
6730	/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
6731	 * network header. output: bpf_fib_lookup sets to gateway address
6732	 * if FIB lookup returns gateway route
6733	 */
6734	union {
6735		__be32		ipv4_dst;
6736		__u32		ipv6_dst[4];  /* in6_addr; network order */
6737	};
6738
6739	/* output */
6740	__be16	h_vlan_proto;
6741	__be16	h_vlan_TCI;
6742	__u8	smac[6];     /* ETH_ALEN */
6743	__u8	dmac[6];     /* ETH_ALEN */
6744};
6745
6746struct bpf_redir_neigh {
6747	/* network family for lookup (AF_INET, AF_INET6) */
6748	__u32 nh_family;
6749	/* network address of nexthop; skips fib lookup to find gateway */
6750	union {
6751		__be32		ipv4_nh;
6752		__u32		ipv6_nh[4];  /* in6_addr; network order */
6753	};
6754};
6755
6756/* bpf_check_mtu flags*/
6757enum  bpf_check_mtu_flags {
6758	BPF_MTU_CHK_SEGS  = (1U << 0),
6759};
6760
6761enum bpf_check_mtu_ret {
6762	BPF_MTU_CHK_RET_SUCCESS,      /* check and lookup successful */
6763	BPF_MTU_CHK_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6764	BPF_MTU_CHK_RET_SEGS_TOOBIG,  /* GSO re-segmentation needed to fwd */
6765};
6766
6767enum bpf_task_fd_type {
6768	BPF_FD_TYPE_RAW_TRACEPOINT,	/* tp name */
6769	BPF_FD_TYPE_TRACEPOINT,		/* tp name */
6770	BPF_FD_TYPE_KPROBE,		/* (symbol + offset) or addr */
6771	BPF_FD_TYPE_KRETPROBE,		/* (symbol + offset) or addr */
6772	BPF_FD_TYPE_UPROBE,		/* filename + offset */
6773	BPF_FD_TYPE_URETPROBE,		/* filename + offset */
6774};
6775
6776enum {
6777	BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG		= (1U << 0),
6778	BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL		= (1U << 1),
6779	BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP		= (1U << 2),
6780};
6781
6782struct bpf_flow_keys {
6783	__u16	nhoff;
6784	__u16	thoff;
6785	__u16	addr_proto;			/* ETH_P_* of valid addrs */
6786	__u8	is_frag;
6787	__u8	is_first_frag;
6788	__u8	is_encap;
6789	__u8	ip_proto;
6790	__be16	n_proto;
6791	__be16	sport;
6792	__be16	dport;
6793	union {
6794		struct {
6795			__be32	ipv4_src;
6796			__be32	ipv4_dst;
6797		};
6798		struct {
6799			__u32	ipv6_src[4];	/* in6_addr; network order */
6800			__u32	ipv6_dst[4];	/* in6_addr; network order */
6801		};
6802	};
6803	__u32	flags;
6804	__be32	flow_label;
6805};
6806
6807struct bpf_func_info {
6808	__u32	insn_off;
6809	__u32	type_id;
6810};
6811
6812#define BPF_LINE_INFO_LINE_NUM(line_col)	((line_col) >> 10)
6813#define BPF_LINE_INFO_LINE_COL(line_col)	((line_col) & 0x3ff)
6814
6815struct bpf_line_info {
6816	__u32	insn_off;
6817	__u32	file_name_off;
6818	__u32	line_off;
6819	__u32	line_col;
6820};
6821
6822struct bpf_spin_lock {
6823	__u32	val;
6824};
6825
6826struct bpf_timer {
6827	__u64 :64;
6828	__u64 :64;
6829} __attribute__((aligned(8)));
6830
6831struct bpf_dynptr {
6832	__u64 :64;
6833	__u64 :64;
6834} __attribute__((aligned(8)));
6835
6836struct bpf_sysctl {
6837	__u32	write;		/* Sysctl is being read (= 0) or written (= 1).
6838				 * Allows 1,2,4-byte read, but no write.
6839				 */
6840	__u32	file_pos;	/* Sysctl file position to read from, write to.
6841				 * Allows 1,2,4-byte read an 4-byte write.
6842				 */
6843};
6844
6845struct bpf_sockopt {
6846	__bpf_md_ptr(struct bpf_sock *, sk);
6847	__bpf_md_ptr(void *, optval);
6848	__bpf_md_ptr(void *, optval_end);
6849
6850	__s32	level;
6851	__s32	optname;
6852	__s32	optlen;
6853	__s32	retval;
6854};
6855
6856struct bpf_pidns_info {
6857	__u32 pid;
6858	__u32 tgid;
6859};
6860
6861/* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
6862struct bpf_sk_lookup {
6863	union {
6864		__bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
6865		__u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */
6866	};
6867
6868	__u32 family;		/* Protocol family (AF_INET, AF_INET6) */
6869	__u32 protocol;		/* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */
6870	__u32 remote_ip4;	/* Network byte order */
6871	__u32 remote_ip6[4];	/* Network byte order */
6872	__be16 remote_port;	/* Network byte order */
6873	__u16 :16;		/* Zero padding */
6874	__u32 local_ip4;	/* Network byte order */
6875	__u32 local_ip6[4];	/* Network byte order */
6876	__u32 local_port;	/* Host byte order */
6877	__u32 ingress_ifindex;		/* The arriving interface. Determined by inet_iif. */
6878};
6879
6880/*
6881 * struct btf_ptr is used for typed pointer representation; the
6882 * type id is used to render the pointer data as the appropriate type
6883 * via the bpf_snprintf_btf() helper described above.  A flags field -
6884 * potentially to specify additional details about the BTF pointer
6885 * (rather than its mode of display) - is included for future use.
6886 * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
6887 */
6888struct btf_ptr {
6889	void *ptr;
6890	__u32 type_id;
6891	__u32 flags;		/* BTF ptr flags; unused at present. */
6892};
6893
6894/*
6895 * Flags to control bpf_snprintf_btf() behaviour.
6896 *     - BTF_F_COMPACT: no formatting around type information
6897 *     - BTF_F_NONAME: no struct/union member names/types
6898 *     - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
6899 *       equivalent to %px.
6900 *     - BTF_F_ZERO: show zero-valued struct/union members; they
6901 *       are not displayed by default
6902 */
6903enum {
6904	BTF_F_COMPACT	=	(1ULL << 0),
6905	BTF_F_NONAME	=	(1ULL << 1),
6906	BTF_F_PTR_RAW	=	(1ULL << 2),
6907	BTF_F_ZERO	=	(1ULL << 3),
6908};
6909
6910/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value
6911 * has to be adjusted by relocations. It is emitted by llvm and passed to
6912 * libbpf and later to the kernel.
6913 */
6914enum bpf_core_relo_kind {
6915	BPF_CORE_FIELD_BYTE_OFFSET = 0,      /* field byte offset */
6916	BPF_CORE_FIELD_BYTE_SIZE = 1,        /* field size in bytes */
6917	BPF_CORE_FIELD_EXISTS = 2,           /* field existence in target kernel */
6918	BPF_CORE_FIELD_SIGNED = 3,           /* field signedness (0 - unsigned, 1 - signed) */
6919	BPF_CORE_FIELD_LSHIFT_U64 = 4,       /* bitfield-specific left bitshift */
6920	BPF_CORE_FIELD_RSHIFT_U64 = 5,       /* bitfield-specific right bitshift */
6921	BPF_CORE_TYPE_ID_LOCAL = 6,          /* type ID in local BPF object */
6922	BPF_CORE_TYPE_ID_TARGET = 7,         /* type ID in target kernel */
6923	BPF_CORE_TYPE_EXISTS = 8,            /* type existence in target kernel */
6924	BPF_CORE_TYPE_SIZE = 9,              /* type size in bytes */
6925	BPF_CORE_ENUMVAL_EXISTS = 10,        /* enum value existence in target kernel */
6926	BPF_CORE_ENUMVAL_VALUE = 11,         /* enum value integer value */
6927	BPF_CORE_TYPE_MATCHES = 12,          /* type match in target kernel */
6928};
6929
6930/*
6931 * "struct bpf_core_relo" is used to pass relocation data form LLVM to libbpf
6932 * and from libbpf to the kernel.
6933 *
6934 * CO-RE relocation captures the following data:
6935 * - insn_off - instruction offset (in bytes) within a BPF program that needs
6936 *   its insn->imm field to be relocated with actual field info;
6937 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable
6938 *   type or field;
6939 * - access_str_off - offset into corresponding .BTF string section. String
6940 *   interpretation depends on specific relocation kind:
6941 *     - for field-based relocations, string encodes an accessed field using
6942 *       a sequence of field and array indices, separated by colon (:). It's
6943 *       conceptually very close to LLVM's getelementptr ([0]) instruction's
6944 *       arguments for identifying offset to a field.
6945 *     - for type-based relocations, strings is expected to be just "0";
6946 *     - for enum value-based relocations, string contains an index of enum
6947 *       value within its enum type;
6948 * - kind - one of enum bpf_core_relo_kind;
6949 *
6950 * Example:
6951 *   struct sample {
6952 *       int a;
6953 *       struct {
6954 *           int b[10];
6955 *       };
6956 *   };
6957 *
6958 *   struct sample *s = ...;
6959 *   int *x = &s->a;     // encoded as "0:0" (a is field #0)
6960 *   int *y = &s->b[5];  // encoded as "0:1:0:5" (anon struct is field #1,
6961 *                       // b is field #0 inside anon struct, accessing elem #5)
6962 *   int *z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
6963 *
6964 * type_id for all relocs in this example will capture BTF type id of
6965 * `struct sample`.
6966 *
6967 * Such relocation is emitted when using __builtin_preserve_access_index()
6968 * Clang built-in, passing expression that captures field address, e.g.:
6969 *
6970 * bpf_probe_read(&dst, sizeof(dst),
6971 *		  __builtin_preserve_access_index(&src->a.b.c));
6972 *
6973 * In this case Clang will emit field relocation recording necessary data to
6974 * be able to find offset of embedded `a.b.c` field within `src` struct.
6975 *
6976 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
6977 */
6978struct bpf_core_relo {
6979	__u32 insn_off;
6980	__u32 type_id;
6981	__u32 access_str_off;
6982	enum bpf_core_relo_kind kind;
6983};
6984
6985#endif /* _UAPI__LINUX_BPF_H__ */
6986