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
90union bpf_iter_link_info {
91	struct {
92		__u32	map_fd;
93	} map;
94};
95
96/* BPF syscall commands, see bpf(2) man-page for more details. */
97/**
98 * DOC: eBPF Syscall Preamble
99 *
100 * The operation to be performed by the **bpf**\ () system call is determined
101 * by the *cmd* argument. Each operation takes an accompanying argument,
102 * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
103 * below). The size argument is the size of the union pointed to by *attr*.
104 */
105/**
106 * DOC: eBPF Syscall Commands
107 *
108 * BPF_MAP_CREATE
109 *	Description
110 *		Create a map and return a file descriptor that refers to the
111 *		map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
112 *		is automatically enabled for the new file descriptor.
113 *
114 *		Applying **close**\ (2) to the file descriptor returned by
115 *		**BPF_MAP_CREATE** will delete the map (but see NOTES).
116 *
117 *	Return
118 *		A new file descriptor (a nonnegative integer), or -1 if an
119 *		error occurred (in which case, *errno* is set appropriately).
120 *
121 * BPF_MAP_LOOKUP_ELEM
122 *	Description
123 *		Look up an element with a given *key* in the map referred to
124 *		by the file descriptor *map_fd*.
125 *
126 *		The *flags* argument may be specified as one of the
127 *		following:
128 *
129 *		**BPF_F_LOCK**
130 *			Look up the value of a spin-locked map without
131 *			returning the lock. This must be specified if the
132 *			elements contain a spinlock.
133 *
134 *	Return
135 *		Returns zero on success. On error, -1 is returned and *errno*
136 *		is set appropriately.
137 *
138 * BPF_MAP_UPDATE_ELEM
139 *	Description
140 *		Create or update an element (key/value pair) in a specified map.
141 *
142 *		The *flags* argument should be specified as one of the
143 *		following:
144 *
145 *		**BPF_ANY**
146 *			Create a new element or update an existing element.
147 *		**BPF_NOEXIST**
148 *			Create a new element only if it did not exist.
149 *		**BPF_EXIST**
150 *			Update an existing element.
151 *		**BPF_F_LOCK**
152 *			Update a spin_lock-ed map element.
153 *
154 *	Return
155 *		Returns zero on success. On error, -1 is returned and *errno*
156 *		is set appropriately.
157 *
158 *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
159 *		**E2BIG**, **EEXIST**, or **ENOENT**.
160 *
161 *		**E2BIG**
162 *			The number of elements in the map reached the
163 *			*max_entries* limit specified at map creation time.
164 *		**EEXIST**
165 *			If *flags* specifies **BPF_NOEXIST** and the element
166 *			with *key* already exists in the map.
167 *		**ENOENT**
168 *			If *flags* specifies **BPF_EXIST** and the element with
169 *			*key* does not exist in the map.
170 *
171 * BPF_MAP_DELETE_ELEM
172 *	Description
173 *		Look up and delete an element by key in a specified map.
174 *
175 *	Return
176 *		Returns zero on success. On error, -1 is returned and *errno*
177 *		is set appropriately.
178 *
179 * BPF_MAP_GET_NEXT_KEY
180 *	Description
181 *		Look up an element by key in a specified map and return the key
182 *		of the next element. Can be used to iterate over all elements
183 *		in the map.
184 *
185 *	Return
186 *		Returns zero on success. On error, -1 is returned and *errno*
187 *		is set appropriately.
188 *
189 *		The following cases can be used to iterate over all elements of
190 *		the map:
191 *
192 *		* If *key* is not found, the operation returns zero and sets
193 *		  the *next_key* pointer to the key of the first element.
194 *		* If *key* is found, the operation returns zero and sets the
195 *		  *next_key* pointer to the key of the next element.
196 *		* If *key* is the last element, returns -1 and *errno* is set
197 *		  to **ENOENT**.
198 *
199 *		May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
200 *		**EINVAL** on error.
201 *
202 * BPF_PROG_LOAD
203 *	Description
204 *		Verify and load an eBPF program, returning a new file
205 *		descriptor associated with the program.
206 *
207 *		Applying **close**\ (2) to the file descriptor returned by
208 *		**BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
209 *
210 *		The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
211 *		automatically enabled for the new file descriptor.
212 *
213 *	Return
214 *		A new file descriptor (a nonnegative integer), or -1 if an
215 *		error occurred (in which case, *errno* is set appropriately).
216 *
217 * BPF_OBJ_PIN
218 *	Description
219 *		Pin an eBPF program or map referred by the specified *bpf_fd*
220 *		to the provided *pathname* on the filesystem.
221 *
222 *		The *pathname* argument must not contain a dot (".").
223 *
224 *		On success, *pathname* retains a reference to the eBPF object,
225 *		preventing deallocation of the object when the original
226 *		*bpf_fd* is closed. This allow the eBPF object to live beyond
227 *		**close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
228 *		process.
229 *
230 *		Applying **unlink**\ (2) or similar calls to the *pathname*
231 *		unpins the object from the filesystem, removing the reference.
232 *		If no other file descriptors or filesystem nodes refer to the
233 *		same object, it will be deallocated (see NOTES).
234 *
235 *		The filesystem type for the parent directory of *pathname* must
236 *		be **BPF_FS_MAGIC**.
237 *
238 *	Return
239 *		Returns zero on success. On error, -1 is returned and *errno*
240 *		is set appropriately.
241 *
242 * BPF_OBJ_GET
243 *	Description
244 *		Open a file descriptor for the eBPF object pinned to the
245 *		specified *pathname*.
246 *
247 *	Return
248 *		A new file descriptor (a nonnegative integer), or -1 if an
249 *		error occurred (in which case, *errno* is set appropriately).
250 *
251 * BPF_PROG_ATTACH
252 *	Description
253 *		Attach an eBPF program to a *target_fd* at the specified
254 *		*attach_type* hook.
255 *
256 *		The *attach_type* specifies the eBPF attachment point to
257 *		attach the program to, and must be one of *bpf_attach_type*
258 *		(see below).
259 *
260 *		The *attach_bpf_fd* must be a valid file descriptor for a
261 *		loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
262 *		or sock_ops type corresponding to the specified *attach_type*.
263 *
264 *		The *target_fd* must be a valid file descriptor for a kernel
265 *		object which depends on the attach type of *attach_bpf_fd*:
266 *
267 *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
268 *		**BPF_PROG_TYPE_CGROUP_SKB**,
269 *		**BPF_PROG_TYPE_CGROUP_SOCK**,
270 *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
271 *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
272 *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
273 *		**BPF_PROG_TYPE_SOCK_OPS**
274 *
275 *			Control Group v2 hierarchy with the eBPF controller
276 *			enabled. Requires the kernel to be compiled with
277 *			**CONFIG_CGROUP_BPF**.
278 *
279 *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
280 *
281 *			Network namespace (eg /proc/self/ns/net).
282 *
283 *		**BPF_PROG_TYPE_LIRC_MODE2**
284 *
285 *			LIRC device path (eg /dev/lircN). Requires the kernel
286 *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
287 *
288 *		**BPF_PROG_TYPE_SK_SKB**,
289 *		**BPF_PROG_TYPE_SK_MSG**
290 *
291 *			eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
292 *
293 *	Return
294 *		Returns zero on success. On error, -1 is returned and *errno*
295 *		is set appropriately.
296 *
297 * BPF_PROG_DETACH
298 *	Description
299 *		Detach the eBPF program associated with the *target_fd* at the
300 *		hook specified by *attach_type*. The program must have been
301 *		previously attached using **BPF_PROG_ATTACH**.
302 *
303 *	Return
304 *		Returns zero on success. On error, -1 is returned and *errno*
305 *		is set appropriately.
306 *
307 * BPF_PROG_TEST_RUN
308 *	Description
309 *		Run the eBPF program associated with the *prog_fd* a *repeat*
310 *		number of times against a provided program context *ctx_in* and
311 *		data *data_in*, and return the modified program context
312 *		*ctx_out*, *data_out* (for example, packet data), result of the
313 *		execution *retval*, and *duration* of the test run.
314 *
315 *		The sizes of the buffers provided as input and output
316 *		parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
317 *		be provided in the corresponding variables *ctx_size_in*,
318 *		*ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
319 *		of these parameters are not provided (ie set to NULL), the
320 *		corresponding size field must be zero.
321 *
322 *		Some program types have particular requirements:
323 *
324 *		**BPF_PROG_TYPE_SK_LOOKUP**
325 *			*data_in* and *data_out* must be NULL.
326 *
327 *		**BPF_PROG_TYPE_RAW_TRACEPOINT**,
328 *		**BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
329 *
330 *			*ctx_out*, *data_in* and *data_out* must be NULL.
331 *			*repeat* must be zero.
332 *
333 *		BPF_PROG_RUN is an alias for BPF_PROG_TEST_RUN.
334 *
335 *	Return
336 *		Returns zero on success. On error, -1 is returned and *errno*
337 *		is set appropriately.
338 *
339 *		**ENOSPC**
340 *			Either *data_size_out* or *ctx_size_out* is too small.
341 *		**ENOTSUPP**
342 *			This command is not supported by the program type of
343 *			the program referred to by *prog_fd*.
344 *
345 * BPF_PROG_GET_NEXT_ID
346 *	Description
347 *		Fetch the next eBPF program currently loaded into the kernel.
348 *
349 *		Looks for the eBPF program with an id greater than *start_id*
350 *		and updates *next_id* on success. If no other eBPF programs
351 *		remain with ids higher than *start_id*, returns -1 and sets
352 *		*errno* to **ENOENT**.
353 *
354 *	Return
355 *		Returns zero on success. On error, or when no id remains, -1
356 *		is returned and *errno* is set appropriately.
357 *
358 * BPF_MAP_GET_NEXT_ID
359 *	Description
360 *		Fetch the next eBPF map currently loaded into the kernel.
361 *
362 *		Looks for the eBPF map with an id greater than *start_id*
363 *		and updates *next_id* on success. If no other eBPF maps
364 *		remain with ids higher than *start_id*, returns -1 and sets
365 *		*errno* to **ENOENT**.
366 *
367 *	Return
368 *		Returns zero on success. On error, or when no id remains, -1
369 *		is returned and *errno* is set appropriately.
370 *
371 * BPF_PROG_GET_FD_BY_ID
372 *	Description
373 *		Open a file descriptor for the eBPF program corresponding to
374 *		*prog_id*.
375 *
376 *	Return
377 *		A new file descriptor (a nonnegative integer), or -1 if an
378 *		error occurred (in which case, *errno* is set appropriately).
379 *
380 * BPF_MAP_GET_FD_BY_ID
381 *	Description
382 *		Open a file descriptor for the eBPF map corresponding to
383 *		*map_id*.
384 *
385 *	Return
386 *		A new file descriptor (a nonnegative integer), or -1 if an
387 *		error occurred (in which case, *errno* is set appropriately).
388 *
389 * BPF_OBJ_GET_INFO_BY_FD
390 *	Description
391 *		Obtain information about the eBPF object corresponding to
392 *		*bpf_fd*.
393 *
394 *		Populates up to *info_len* bytes of *info*, which will be in
395 *		one of the following formats depending on the eBPF object type
396 *		of *bpf_fd*:
397 *
398 *		* **struct bpf_prog_info**
399 *		* **struct bpf_map_info**
400 *		* **struct bpf_btf_info**
401 *		* **struct bpf_link_info**
402 *
403 *	Return
404 *		Returns zero on success. On error, -1 is returned and *errno*
405 *		is set appropriately.
406 *
407 * BPF_PROG_QUERY
408 *	Description
409 *		Obtain information about eBPF programs associated with the
410 *		specified *attach_type* hook.
411 *
412 *		The *target_fd* must be a valid file descriptor for a kernel
413 *		object which depends on the attach type of *attach_bpf_fd*:
414 *
415 *		**BPF_PROG_TYPE_CGROUP_DEVICE**,
416 *		**BPF_PROG_TYPE_CGROUP_SKB**,
417 *		**BPF_PROG_TYPE_CGROUP_SOCK**,
418 *		**BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
419 *		**BPF_PROG_TYPE_CGROUP_SOCKOPT**,
420 *		**BPF_PROG_TYPE_CGROUP_SYSCTL**,
421 *		**BPF_PROG_TYPE_SOCK_OPS**
422 *
423 *			Control Group v2 hierarchy with the eBPF controller
424 *			enabled. Requires the kernel to be compiled with
425 *			**CONFIG_CGROUP_BPF**.
426 *
427 *		**BPF_PROG_TYPE_FLOW_DISSECTOR**
428 *
429 *			Network namespace (eg /proc/self/ns/net).
430 *
431 *		**BPF_PROG_TYPE_LIRC_MODE2**
432 *
433 *			LIRC device path (eg /dev/lircN). Requires the kernel
434 *			to be compiled with **CONFIG_BPF_LIRC_MODE2**.
435 *
436 *		**BPF_PROG_QUERY** always fetches the number of programs
437 *		attached and the *attach_flags* which were used to attach those
438 *		programs. Additionally, if *prog_ids* is nonzero and the number
439 *		of attached programs is less than *prog_cnt*, populates
440 *		*prog_ids* with the eBPF program ids of the programs attached
441 *		at *target_fd*.
442 *
443 *		The following flags may alter the result:
444 *
445 *		**BPF_F_QUERY_EFFECTIVE**
446 *			Only return information regarding programs which are
447 *			currently effective at the specified *target_fd*.
448 *
449 *	Return
450 *		Returns zero on success. On error, -1 is returned and *errno*
451 *		is set appropriately.
452 *
453 * BPF_RAW_TRACEPOINT_OPEN
454 *	Description
455 *		Attach an eBPF program to a tracepoint *name* to access kernel
456 *		internal arguments of the tracepoint in their raw form.
457 *
458 *		The *prog_fd* must be a valid file descriptor associated with
459 *		a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
460 *
461 *		No ABI guarantees are made about the content of tracepoint
462 *		arguments exposed to the corresponding eBPF program.
463 *
464 *		Applying **close**\ (2) to the file descriptor returned by
465 *		**BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
466 *
467 *	Return
468 *		A new file descriptor (a nonnegative integer), or -1 if an
469 *		error occurred (in which case, *errno* is set appropriately).
470 *
471 * BPF_BTF_LOAD
472 *	Description
473 *		Verify and load BPF Type Format (BTF) metadata into the kernel,
474 *		returning a new file descriptor associated with the metadata.
475 *		BTF is described in more detail at
476 *		https://www.kernel.org/doc/html/latest/bpf/btf.html.
477 *
478 *		The *btf* parameter must point to valid memory providing
479 *		*btf_size* bytes of BTF binary metadata.
480 *
481 *		The returned file descriptor can be passed to other **bpf**\ ()
482 *		subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
483 *		associate the BTF with those objects.
484 *
485 *		Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
486 *		parameters to specify a *btf_log_buf*, *btf_log_size* and
487 *		*btf_log_level* which allow the kernel to return freeform log
488 *		output regarding the BTF verification process.
489 *
490 *	Return
491 *		A new file descriptor (a nonnegative integer), or -1 if an
492 *		error occurred (in which case, *errno* is set appropriately).
493 *
494 * BPF_BTF_GET_FD_BY_ID
495 *	Description
496 *		Open a file descriptor for the BPF Type Format (BTF)
497 *		corresponding to *btf_id*.
498 *
499 *	Return
500 *		A new file descriptor (a nonnegative integer), or -1 if an
501 *		error occurred (in which case, *errno* is set appropriately).
502 *
503 * BPF_TASK_FD_QUERY
504 *	Description
505 *		Obtain information about eBPF programs associated with the
506 *		target process identified by *pid* and *fd*.
507 *
508 *		If the *pid* and *fd* are associated with a tracepoint, kprobe
509 *		or uprobe perf event, then the *prog_id* and *fd_type* will
510 *		be populated with the eBPF program id and file descriptor type
511 *		of type **bpf_task_fd_type**. If associated with a kprobe or
512 *		uprobe, the  *probe_offset* and *probe_addr* will also be
513 *		populated. Optionally, if *buf* is provided, then up to
514 *		*buf_len* bytes of *buf* will be populated with the name of
515 *		the tracepoint, kprobe or uprobe.
516 *
517 *		The resulting *prog_id* may be introspected in deeper detail
518 *		using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
519 *
520 *	Return
521 *		Returns zero on success. On error, -1 is returned and *errno*
522 *		is set appropriately.
523 *
524 * BPF_MAP_LOOKUP_AND_DELETE_ELEM
525 *	Description
526 *		Look up an element with the given *key* in the map referred to
527 *		by the file descriptor *fd*, and if found, delete the element.
528 *
529 *		For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
530 *		types, the *flags* argument needs to be set to 0, but for other
531 *		map types, it may be specified as:
532 *
533 *		**BPF_F_LOCK**
534 *			Look up and delete the value of a spin-locked map
535 *			without returning the lock. This must be specified if
536 *			the elements contain a spinlock.
537 *
538 *		The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
539 *		implement this command as a "pop" operation, deleting the top
540 *		element rather than one corresponding to *key*.
541 *		The *key* and *key_len* parameters should be zeroed when
542 *		issuing this operation for these map types.
543 *
544 *		This command is only valid for the following map types:
545 *		* **BPF_MAP_TYPE_QUEUE**
546 *		* **BPF_MAP_TYPE_STACK**
547 *		* **BPF_MAP_TYPE_HASH**
548 *		* **BPF_MAP_TYPE_PERCPU_HASH**
549 *		* **BPF_MAP_TYPE_LRU_HASH**
550 *		* **BPF_MAP_TYPE_LRU_PERCPU_HASH**
551 *
552 *	Return
553 *		Returns zero on success. On error, -1 is returned and *errno*
554 *		is set appropriately.
555 *
556 * BPF_MAP_FREEZE
557 *	Description
558 *		Freeze the permissions of the specified map.
559 *
560 *		Write permissions may be frozen by passing zero *flags*.
561 *		Upon success, no future syscall invocations may alter the
562 *		map state of *map_fd*. Write operations from eBPF programs
563 *		are still possible for a frozen map.
564 *
565 *		Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
566 *
567 *	Return
568 *		Returns zero on success. On error, -1 is returned and *errno*
569 *		is set appropriately.
570 *
571 * BPF_BTF_GET_NEXT_ID
572 *	Description
573 *		Fetch the next BPF Type Format (BTF) object currently loaded
574 *		into the kernel.
575 *
576 *		Looks for the BTF object with an id greater than *start_id*
577 *		and updates *next_id* on success. If no other BTF objects
578 *		remain with ids higher than *start_id*, returns -1 and sets
579 *		*errno* to **ENOENT**.
580 *
581 *	Return
582 *		Returns zero on success. On error, or when no id remains, -1
583 *		is returned and *errno* is set appropriately.
584 *
585 * BPF_MAP_LOOKUP_BATCH
586 *	Description
587 *		Iterate and fetch multiple elements in a map.
588 *
589 *		Two opaque values are used to manage batch operations,
590 *		*in_batch* and *out_batch*. Initially, *in_batch* must be set
591 *		to NULL to begin the batched operation. After each subsequent
592 *		**BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
593 *		*out_batch* as the *in_batch* for the next operation to
594 *		continue iteration from the current point.
595 *
596 *		The *keys* and *values* are output parameters which must point
597 *		to memory large enough to hold *count* items based on the key
598 *		and value size of the map *map_fd*. The *keys* buffer must be
599 *		of *key_size* * *count*. The *values* buffer must be of
600 *		*value_size* * *count*.
601 *
602 *		The *elem_flags* argument may be specified as one of the
603 *		following:
604 *
605 *		**BPF_F_LOCK**
606 *			Look up the value of a spin-locked map without
607 *			returning the lock. This must be specified if the
608 *			elements contain a spinlock.
609 *
610 *		On success, *count* elements from the map are copied into the
611 *		user buffer, with the keys copied into *keys* and the values
612 *		copied into the corresponding indices in *values*.
613 *
614 *		If an error is returned and *errno* is not **EFAULT**, *count*
615 *		is set to the number of successfully processed elements.
616 *
617 *	Return
618 *		Returns zero on success. On error, -1 is returned and *errno*
619 *		is set appropriately.
620 *
621 *		May set *errno* to **ENOSPC** to indicate that *keys* or
622 *		*values* is too small to dump an entire bucket during
623 *		iteration of a hash-based map type.
624 *
625 * BPF_MAP_LOOKUP_AND_DELETE_BATCH
626 *	Description
627 *		Iterate and delete all elements in a map.
628 *
629 *		This operation has the same behavior as
630 *		**BPF_MAP_LOOKUP_BATCH** with two exceptions:
631 *
632 *		* Every element that is successfully returned is also deleted
633 *		  from the map. This is at least *count* elements. Note that
634 *		  *count* is both an input and an output parameter.
635 *		* Upon returning with *errno* set to **EFAULT**, up to
636 *		  *count* elements may be deleted without returning the keys
637 *		  and values of the deleted elements.
638 *
639 *	Return
640 *		Returns zero on success. On error, -1 is returned and *errno*
641 *		is set appropriately.
642 *
643 * BPF_MAP_UPDATE_BATCH
644 *	Description
645 *		Update multiple elements in a map by *key*.
646 *
647 *		The *keys* and *values* are input parameters which must point
648 *		to memory large enough to hold *count* items based on the key
649 *		and value size of the map *map_fd*. The *keys* buffer must be
650 *		of *key_size* * *count*. The *values* buffer must be of
651 *		*value_size* * *count*.
652 *
653 *		Each element specified in *keys* is sequentially updated to the
654 *		value in the corresponding index in *values*. The *in_batch*
655 *		and *out_batch* parameters are ignored and should be zeroed.
656 *
657 *		The *elem_flags* argument should be specified as one of the
658 *		following:
659 *
660 *		**BPF_ANY**
661 *			Create new elements or update a existing elements.
662 *		**BPF_NOEXIST**
663 *			Create new elements only if they do not exist.
664 *		**BPF_EXIST**
665 *			Update existing elements.
666 *		**BPF_F_LOCK**
667 *			Update spin_lock-ed map elements. This must be
668 *			specified if the map value contains a spinlock.
669 *
670 *		On success, *count* elements from the map are updated.
671 *
672 *		If an error is returned and *errno* is not **EFAULT**, *count*
673 *		is set to the number of successfully processed elements.
674 *
675 *	Return
676 *		Returns zero on success. On error, -1 is returned and *errno*
677 *		is set appropriately.
678 *
679 *		May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
680 *		**E2BIG**. **E2BIG** indicates that the number of elements in
681 *		the map reached the *max_entries* limit specified at map
682 *		creation time.
683 *
684 *		May set *errno* to one of the following error codes under
685 *		specific circumstances:
686 *
687 *		**EEXIST**
688 *			If *flags* specifies **BPF_NOEXIST** and the element
689 *			with *key* already exists in the map.
690 *		**ENOENT**
691 *			If *flags* specifies **BPF_EXIST** and the element with
692 *			*key* does not exist in the map.
693 *
694 * BPF_MAP_DELETE_BATCH
695 *	Description
696 *		Delete multiple elements in a map by *key*.
697 *
698 *		The *keys* parameter is an input parameter which must point
699 *		to memory large enough to hold *count* items based on the key
700 *		size of the map *map_fd*, that is, *key_size* * *count*.
701 *
702 *		Each element specified in *keys* is sequentially deleted. The
703 *		*in_batch*, *out_batch*, and *values* parameters are ignored
704 *		and should be zeroed.
705 *
706 *		The *elem_flags* argument may be specified as one of the
707 *		following:
708 *
709 *		**BPF_F_LOCK**
710 *			Look up the value of a spin-locked map without
711 *			returning the lock. This must be specified if the
712 *			elements contain a spinlock.
713 *
714 *		On success, *count* elements from the map are updated.
715 *
716 *		If an error is returned and *errno* is not **EFAULT**, *count*
717 *		is set to the number of successfully processed elements. If
718 *		*errno* is **EFAULT**, up to *count* elements may be been
719 *		deleted.
720 *
721 *	Return
722 *		Returns zero on success. On error, -1 is returned and *errno*
723 *		is set appropriately.
724 *
725 * BPF_LINK_CREATE
726 *	Description
727 *		Attach an eBPF program to a *target_fd* at the specified
728 *		*attach_type* hook and return a file descriptor handle for
729 *		managing the link.
730 *
731 *	Return
732 *		A new file descriptor (a nonnegative integer), or -1 if an
733 *		error occurred (in which case, *errno* is set appropriately).
734 *
735 * BPF_LINK_UPDATE
736 *	Description
737 *		Update the eBPF program in the specified *link_fd* to
738 *		*new_prog_fd*.
739 *
740 *	Return
741 *		Returns zero on success. On error, -1 is returned and *errno*
742 *		is set appropriately.
743 *
744 * BPF_LINK_GET_FD_BY_ID
745 *	Description
746 *		Open a file descriptor for the eBPF Link corresponding to
747 *		*link_id*.
748 *
749 *	Return
750 *		A new file descriptor (a nonnegative integer), or -1 if an
751 *		error occurred (in which case, *errno* is set appropriately).
752 *
753 * BPF_LINK_GET_NEXT_ID
754 *	Description
755 *		Fetch the next eBPF link currently loaded into the kernel.
756 *
757 *		Looks for the eBPF link with an id greater than *start_id*
758 *		and updates *next_id* on success. If no other eBPF links
759 *		remain with ids higher than *start_id*, returns -1 and sets
760 *		*errno* to **ENOENT**.
761 *
762 *	Return
763 *		Returns zero on success. On error, or when no id remains, -1
764 *		is returned and *errno* is set appropriately.
765 *
766 * BPF_ENABLE_STATS
767 *	Description
768 *		Enable eBPF runtime statistics gathering.
769 *
770 *		Runtime statistics gathering for the eBPF runtime is disabled
771 *		by default to minimize the corresponding performance overhead.
772 *		This command enables statistics globally.
773 *
774 *		Multiple programs may independently enable statistics.
775 *		After gathering the desired statistics, eBPF runtime statistics
776 *		may be disabled again by calling **close**\ (2) for the file
777 *		descriptor returned by this function. Statistics will only be
778 *		disabled system-wide when all outstanding file descriptors
779 *		returned by prior calls for this subcommand are closed.
780 *
781 *	Return
782 *		A new file descriptor (a nonnegative integer), or -1 if an
783 *		error occurred (in which case, *errno* is set appropriately).
784 *
785 * BPF_ITER_CREATE
786 *	Description
787 *		Create an iterator on top of the specified *link_fd* (as
788 *		previously created using **BPF_LINK_CREATE**) and return a
789 *		file descriptor that can be used to trigger the iteration.
790 *
791 *		If the resulting file descriptor is pinned to the filesystem
792 *		using  **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
793 *		for that path will trigger the iterator to read kernel state
794 *		using the eBPF program attached to *link_fd*.
795 *
796 *	Return
797 *		A new file descriptor (a nonnegative integer), or -1 if an
798 *		error occurred (in which case, *errno* is set appropriately).
799 *
800 * BPF_LINK_DETACH
801 *	Description
802 *		Forcefully detach the specified *link_fd* from its
803 *		corresponding attachment point.
804 *
805 *	Return
806 *		Returns zero on success. On error, -1 is returned and *errno*
807 *		is set appropriately.
808 *
809 * BPF_PROG_BIND_MAP
810 *	Description
811 *		Bind a map to the lifetime of an eBPF program.
812 *
813 *		The map identified by *map_fd* is bound to the program
814 *		identified by *prog_fd* and only released when *prog_fd* is
815 *		released. This may be used in cases where metadata should be
816 *		associated with a program which otherwise does not contain any
817 *		references to the map (for example, embedded in the eBPF
818 *		program instructions).
819 *
820 *	Return
821 *		Returns zero on success. On error, -1 is returned and *errno*
822 *		is set appropriately.
823 *
824 * NOTES
825 *	eBPF objects (maps and programs) can be shared between processes.
826 *
827 *	* After **fork**\ (2), the child inherits file descriptors
828 *	  referring to the same eBPF objects.
829 *	* File descriptors referring to eBPF objects can be transferred over
830 *	  **unix**\ (7) domain sockets.
831 *	* File descriptors referring to eBPF objects can be duplicated in the
832 *	  usual way, using **dup**\ (2) and similar calls.
833 *	* File descriptors referring to eBPF objects can be pinned to the
834 *	  filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
835 *
836 *	An eBPF object is deallocated only after all file descriptors referring
837 *	to the object have been closed and no references remain pinned to the
838 *	filesystem or attached (for example, bound to a program or device).
839 */
840enum bpf_cmd {
841	BPF_MAP_CREATE,
842	BPF_MAP_LOOKUP_ELEM,
843	BPF_MAP_UPDATE_ELEM,
844	BPF_MAP_DELETE_ELEM,
845	BPF_MAP_GET_NEXT_KEY,
846	BPF_PROG_LOAD,
847	BPF_OBJ_PIN,
848	BPF_OBJ_GET,
849	BPF_PROG_ATTACH,
850	BPF_PROG_DETACH,
851	BPF_PROG_TEST_RUN,
852	BPF_PROG_RUN = BPF_PROG_TEST_RUN,
853	BPF_PROG_GET_NEXT_ID,
854	BPF_MAP_GET_NEXT_ID,
855	BPF_PROG_GET_FD_BY_ID,
856	BPF_MAP_GET_FD_BY_ID,
857	BPF_OBJ_GET_INFO_BY_FD,
858	BPF_PROG_QUERY,
859	BPF_RAW_TRACEPOINT_OPEN,
860	BPF_BTF_LOAD,
861	BPF_BTF_GET_FD_BY_ID,
862	BPF_TASK_FD_QUERY,
863	BPF_MAP_LOOKUP_AND_DELETE_ELEM,
864	BPF_MAP_FREEZE,
865	BPF_BTF_GET_NEXT_ID,
866	BPF_MAP_LOOKUP_BATCH,
867	BPF_MAP_LOOKUP_AND_DELETE_BATCH,
868	BPF_MAP_UPDATE_BATCH,
869	BPF_MAP_DELETE_BATCH,
870	BPF_LINK_CREATE,
871	BPF_LINK_UPDATE,
872	BPF_LINK_GET_FD_BY_ID,
873	BPF_LINK_GET_NEXT_ID,
874	BPF_ENABLE_STATS,
875	BPF_ITER_CREATE,
876	BPF_LINK_DETACH,
877	BPF_PROG_BIND_MAP,
878};
879
880enum bpf_map_type {
881	BPF_MAP_TYPE_UNSPEC,
882	BPF_MAP_TYPE_HASH,
883	BPF_MAP_TYPE_ARRAY,
884	BPF_MAP_TYPE_PROG_ARRAY,
885	BPF_MAP_TYPE_PERF_EVENT_ARRAY,
886	BPF_MAP_TYPE_PERCPU_HASH,
887	BPF_MAP_TYPE_PERCPU_ARRAY,
888	BPF_MAP_TYPE_STACK_TRACE,
889	BPF_MAP_TYPE_CGROUP_ARRAY,
890	BPF_MAP_TYPE_LRU_HASH,
891	BPF_MAP_TYPE_LRU_PERCPU_HASH,
892	BPF_MAP_TYPE_LPM_TRIE,
893	BPF_MAP_TYPE_ARRAY_OF_MAPS,
894	BPF_MAP_TYPE_HASH_OF_MAPS,
895	BPF_MAP_TYPE_DEVMAP,
896	BPF_MAP_TYPE_SOCKMAP,
897	BPF_MAP_TYPE_CPUMAP,
898	BPF_MAP_TYPE_XSKMAP,
899	BPF_MAP_TYPE_SOCKHASH,
900	BPF_MAP_TYPE_CGROUP_STORAGE,
901	BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
902	BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
903	BPF_MAP_TYPE_QUEUE,
904	BPF_MAP_TYPE_STACK,
905	BPF_MAP_TYPE_SK_STORAGE,
906	BPF_MAP_TYPE_DEVMAP_HASH,
907	BPF_MAP_TYPE_STRUCT_OPS,
908	BPF_MAP_TYPE_RINGBUF,
909	BPF_MAP_TYPE_INODE_STORAGE,
910	BPF_MAP_TYPE_TASK_STORAGE,
911	BPF_MAP_TYPE_BLOOM_FILTER,
912};
913
914/* Note that tracing related programs such as
915 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
916 * are not subject to a stable API since kernel internal data
917 * structures can change from release to release and may
918 * therefore break existing tracing BPF programs. Tracing BPF
919 * programs correspond to /a/ specific kernel which is to be
920 * analyzed, and not /a/ specific kernel /and/ all future ones.
921 */
922enum bpf_prog_type {
923	BPF_PROG_TYPE_UNSPEC,
924	BPF_PROG_TYPE_SOCKET_FILTER,
925	BPF_PROG_TYPE_KPROBE,
926	BPF_PROG_TYPE_SCHED_CLS,
927	BPF_PROG_TYPE_SCHED_ACT,
928	BPF_PROG_TYPE_TRACEPOINT,
929	BPF_PROG_TYPE_XDP,
930	BPF_PROG_TYPE_PERF_EVENT,
931	BPF_PROG_TYPE_CGROUP_SKB,
932	BPF_PROG_TYPE_CGROUP_SOCK,
933	BPF_PROG_TYPE_LWT_IN,
934	BPF_PROG_TYPE_LWT_OUT,
935	BPF_PROG_TYPE_LWT_XMIT,
936	BPF_PROG_TYPE_SOCK_OPS,
937	BPF_PROG_TYPE_SK_SKB,
938	BPF_PROG_TYPE_CGROUP_DEVICE,
939	BPF_PROG_TYPE_SK_MSG,
940	BPF_PROG_TYPE_RAW_TRACEPOINT,
941	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
942	BPF_PROG_TYPE_LWT_SEG6LOCAL,
943	BPF_PROG_TYPE_LIRC_MODE2,
944	BPF_PROG_TYPE_SK_REUSEPORT,
945	BPF_PROG_TYPE_FLOW_DISSECTOR,
946	BPF_PROG_TYPE_CGROUP_SYSCTL,
947	BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
948	BPF_PROG_TYPE_CGROUP_SOCKOPT,
949	BPF_PROG_TYPE_TRACING,
950	BPF_PROG_TYPE_STRUCT_OPS,
951	BPF_PROG_TYPE_EXT,
952	BPF_PROG_TYPE_LSM,
953	BPF_PROG_TYPE_SK_LOOKUP,
954	BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
955};
956
957enum bpf_attach_type {
958	BPF_CGROUP_INET_INGRESS,
959	BPF_CGROUP_INET_EGRESS,
960	BPF_CGROUP_INET_SOCK_CREATE,
961	BPF_CGROUP_SOCK_OPS,
962	BPF_SK_SKB_STREAM_PARSER,
963	BPF_SK_SKB_STREAM_VERDICT,
964	BPF_CGROUP_DEVICE,
965	BPF_SK_MSG_VERDICT,
966	BPF_CGROUP_INET4_BIND,
967	BPF_CGROUP_INET6_BIND,
968	BPF_CGROUP_INET4_CONNECT,
969	BPF_CGROUP_INET6_CONNECT,
970	BPF_CGROUP_INET4_POST_BIND,
971	BPF_CGROUP_INET6_POST_BIND,
972	BPF_CGROUP_UDP4_SENDMSG,
973	BPF_CGROUP_UDP6_SENDMSG,
974	BPF_LIRC_MODE2,
975	BPF_FLOW_DISSECTOR,
976	BPF_CGROUP_SYSCTL,
977	BPF_CGROUP_UDP4_RECVMSG,
978	BPF_CGROUP_UDP6_RECVMSG,
979	BPF_CGROUP_GETSOCKOPT,
980	BPF_CGROUP_SETSOCKOPT,
981	BPF_TRACE_RAW_TP,
982	BPF_TRACE_FENTRY,
983	BPF_TRACE_FEXIT,
984	BPF_MODIFY_RETURN,
985	BPF_LSM_MAC,
986	BPF_TRACE_ITER,
987	BPF_CGROUP_INET4_GETPEERNAME,
988	BPF_CGROUP_INET6_GETPEERNAME,
989	BPF_CGROUP_INET4_GETSOCKNAME,
990	BPF_CGROUP_INET6_GETSOCKNAME,
991	BPF_XDP_DEVMAP,
992	BPF_CGROUP_INET_SOCK_RELEASE,
993	BPF_XDP_CPUMAP,
994	BPF_SK_LOOKUP,
995	BPF_XDP,
996	BPF_SK_SKB_VERDICT,
997	BPF_SK_REUSEPORT_SELECT,
998	BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
999	BPF_PERF_EVENT,
1000	BPF_TRACE_KPROBE_MULTI,
1001	__MAX_BPF_ATTACH_TYPE
1002};
1003
1004#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1005
1006enum bpf_link_type {
1007	BPF_LINK_TYPE_UNSPEC = 0,
1008	BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
1009	BPF_LINK_TYPE_TRACING = 2,
1010	BPF_LINK_TYPE_CGROUP = 3,
1011	BPF_LINK_TYPE_ITER = 4,
1012	BPF_LINK_TYPE_NETNS = 5,
1013	BPF_LINK_TYPE_XDP = 6,
1014	BPF_LINK_TYPE_PERF_EVENT = 7,
1015	BPF_LINK_TYPE_KPROBE_MULTI = 8,
1016	BPF_LINK_TYPE_STRUCT_OPS = 9,
1017
1018	MAX_BPF_LINK_TYPE,
1019};
1020
1021/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
1022 *
1023 * NONE(default): No further bpf programs allowed in the subtree.
1024 *
1025 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1026 * the program in this cgroup yields to sub-cgroup program.
1027 *
1028 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1029 * that cgroup program gets run in addition to the program in this cgroup.
1030 *
1031 * Only one program is allowed to be attached to a cgroup with
1032 * NONE or BPF_F_ALLOW_OVERRIDE flag.
1033 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1034 * release old program and attach the new one. Attach flags has to match.
1035 *
1036 * Multiple programs are allowed to be attached to a cgroup with
1037 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1038 * (those that were attached first, run first)
1039 * The programs of sub-cgroup are executed first, then programs of
1040 * this cgroup and then programs of parent cgroup.
1041 * When children program makes decision (like picking TCP CA or sock bind)
1042 * parent program has a chance to override it.
1043 *
1044 * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1045 * programs for a cgroup. Though it's possible to replace an old program at
1046 * any position by also specifying BPF_F_REPLACE flag and position itself in
1047 * replace_bpf_fd attribute. Old program at this position will be released.
1048 *
1049 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1050 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
1051 * Ex1:
1052 * cgrp1 (MULTI progs A, B) ->
1053 *    cgrp2 (OVERRIDE prog C) ->
1054 *      cgrp3 (MULTI prog D) ->
1055 *        cgrp4 (OVERRIDE prog E) ->
1056 *          cgrp5 (NONE prog F)
1057 * the event in cgrp5 triggers execution of F,D,A,B in that order.
1058 * if prog F is detached, the execution is E,D,A,B
1059 * if prog F and D are detached, the execution is E,A,B
1060 * if prog F, E and D are detached, the execution is C,A,B
1061 *
1062 * All eligible programs are executed regardless of return code from
1063 * earlier programs.
1064 */
1065#define BPF_F_ALLOW_OVERRIDE	(1U << 0)
1066#define BPF_F_ALLOW_MULTI	(1U << 1)
1067#define BPF_F_REPLACE		(1U << 2)
1068
1069/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
1070 * verifier will perform strict alignment checking as if the kernel
1071 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1072 * and NET_IP_ALIGN defined to 2.
1073 */
1074#define BPF_F_STRICT_ALIGNMENT	(1U << 0)
1075
1076/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
1077 * verifier will allow any alignment whatsoever.  On platforms
1078 * with strict alignment requirements for loads ands stores (such
1079 * as sparc and mips) the verifier validates that all loads and
1080 * stores provably follow this requirement.  This flag turns that
1081 * checking and enforcement off.
1082 *
1083 * It is mostly used for testing when we want to validate the
1084 * context and memory access aspects of the verifier, but because
1085 * of an unaligned access the alignment check would trigger before
1086 * the one we are interested in.
1087 */
1088#define BPF_F_ANY_ALIGNMENT	(1U << 1)
1089
1090/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
1091 * Verifier does sub-register def/use analysis and identifies instructions whose
1092 * def only matters for low 32-bit, high 32-bit is never referenced later
1093 * through implicit zero extension. Therefore verifier notifies JIT back-ends
1094 * that it is safe to ignore clearing high 32-bit for these instructions. This
1095 * saves some back-ends a lot of code-gen. However such optimization is not
1096 * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1097 * hence hasn't used verifier's analysis result. But, we really want to have a
1098 * way to be able to verify the correctness of the described optimization on
1099 * x86_64 on which testsuites are frequently exercised.
1100 *
1101 * So, this flag is introduced. Once it is set, verifier will randomize high
1102 * 32-bit for those instructions who has been identified as safe to ignore them.
1103 * Then, if verifier is not doing correct analysis, such randomization will
1104 * regress tests to expose bugs.
1105 */
1106#define BPF_F_TEST_RND_HI32	(1U << 2)
1107
1108/* The verifier internal test flag. Behavior is undefined */
1109#define BPF_F_TEST_STATE_FREQ	(1U << 3)
1110
1111/* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
1112 * restrict map and helper usage for such programs. Sleepable BPF programs can
1113 * only be attached to hooks where kernel execution context allows sleeping.
1114 * Such programs are allowed to use helpers that may sleep like
1115 * bpf_copy_from_user().
1116 */
1117#define BPF_F_SLEEPABLE		(1U << 4)
1118
1119/* If BPF_F_XDP_HAS_FRAGS is used in BPF_PROG_LOAD command, the loaded program
1120 * fully support xdp frags.
1121 */
1122#define BPF_F_XDP_HAS_FRAGS	(1U << 5)
1123
1124/* link_create.kprobe_multi.flags used in LINK_CREATE command for
1125 * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
1126 */
1127#define BPF_F_KPROBE_MULTI_RETURN	(1U << 0)
1128
1129/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
1130 * the following extensions:
1131 *
1132 * insn[0].src_reg:  BPF_PSEUDO_MAP_[FD|IDX]
1133 * insn[0].imm:      map fd or fd_idx
1134 * insn[1].imm:      0
1135 * insn[0].off:      0
1136 * insn[1].off:      0
1137 * ldimm64 rewrite:  address of map
1138 * verifier type:    CONST_PTR_TO_MAP
1139 */
1140#define BPF_PSEUDO_MAP_FD	1
1141#define BPF_PSEUDO_MAP_IDX	5
1142
1143/* insn[0].src_reg:  BPF_PSEUDO_MAP_[IDX_]VALUE
1144 * insn[0].imm:      map fd or fd_idx
1145 * insn[1].imm:      offset into value
1146 * insn[0].off:      0
1147 * insn[1].off:      0
1148 * ldimm64 rewrite:  address of map[0]+offset
1149 * verifier type:    PTR_TO_MAP_VALUE
1150 */
1151#define BPF_PSEUDO_MAP_VALUE		2
1152#define BPF_PSEUDO_MAP_IDX_VALUE	6
1153
1154/* insn[0].src_reg:  BPF_PSEUDO_BTF_ID
1155 * insn[0].imm:      kernel btd id of VAR
1156 * insn[1].imm:      0
1157 * insn[0].off:      0
1158 * insn[1].off:      0
1159 * ldimm64 rewrite:  address of the kernel variable
1160 * verifier type:    PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1161 *                   is struct/union.
1162 */
1163#define BPF_PSEUDO_BTF_ID	3
1164/* insn[0].src_reg:  BPF_PSEUDO_FUNC
1165 * insn[0].imm:      insn offset to the func
1166 * insn[1].imm:      0
1167 * insn[0].off:      0
1168 * insn[1].off:      0
1169 * ldimm64 rewrite:  address of the function
1170 * verifier type:    PTR_TO_FUNC.
1171 */
1172#define BPF_PSEUDO_FUNC		4
1173
1174/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
1175 * offset to another bpf function
1176 */
1177#define BPF_PSEUDO_CALL		1
1178/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
1179 * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1180 */
1181#define BPF_PSEUDO_KFUNC_CALL	2
1182
1183/* flags for BPF_MAP_UPDATE_ELEM command */
1184enum {
1185	BPF_ANY		= 0, /* create new element or update existing */
1186	BPF_NOEXIST	= 1, /* create new element if it didn't exist */
1187	BPF_EXIST	= 2, /* update existing element */
1188	BPF_F_LOCK	= 4, /* spin_lock-ed map_lookup/map_update */
1189};
1190
1191/* flags for BPF_MAP_CREATE command */
1192enum {
1193	BPF_F_NO_PREALLOC	= (1U << 0),
1194/* Instead of having one common LRU list in the
1195 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1196 * which can scale and perform better.
1197 * Note, the LRU nodes (including free nodes) cannot be moved
1198 * across different LRU lists.
1199 */
1200	BPF_F_NO_COMMON_LRU	= (1U << 1),
1201/* Specify numa node during map creation */
1202	BPF_F_NUMA_NODE		= (1U << 2),
1203
1204/* Flags for accessing BPF object from syscall side. */
1205	BPF_F_RDONLY		= (1U << 3),
1206	BPF_F_WRONLY		= (1U << 4),
1207
1208/* Flag for stack_map, store build_id+offset instead of pointer */
1209	BPF_F_STACK_BUILD_ID	= (1U << 5),
1210
1211/* Zero-initialize hash function seed. This should only be used for testing. */
1212	BPF_F_ZERO_SEED		= (1U << 6),
1213
1214/* Flags for accessing BPF object from program side. */
1215	BPF_F_RDONLY_PROG	= (1U << 7),
1216	BPF_F_WRONLY_PROG	= (1U << 8),
1217
1218/* Clone map from listener for newly accepted socket */
1219	BPF_F_CLONE		= (1U << 9),
1220
1221/* Enable memory-mapping BPF map */
1222	BPF_F_MMAPABLE		= (1U << 10),
1223
1224/* Share perf_event among processes */
1225	BPF_F_PRESERVE_ELEMS	= (1U << 11),
1226
1227/* Create a map that is suitable to be an inner map with dynamic max entries */
1228	BPF_F_INNER_MAP		= (1U << 12),
1229};
1230
1231/* Flags for BPF_PROG_QUERY. */
1232
1233/* Query effective (directly attached + inherited from ancestor cgroups)
1234 * programs that will be executed for events within a cgroup.
1235 * attach_flags with this flag are returned only for directly attached programs.
1236 */
1237#define BPF_F_QUERY_EFFECTIVE	(1U << 0)
1238
1239/* Flags for BPF_PROG_TEST_RUN */
1240
1241/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
1242#define BPF_F_TEST_RUN_ON_CPU	(1U << 0)
1243/* If set, XDP frames will be transmitted after processing */
1244#define BPF_F_TEST_XDP_LIVE_FRAMES	(1U << 1)
1245
1246/* type for BPF_ENABLE_STATS */
1247enum bpf_stats_type {
1248	/* enabled run_time_ns and run_cnt */
1249	BPF_STATS_RUN_TIME = 0,
1250};
1251
1252enum bpf_stack_build_id_status {
1253	/* user space need an empty entry to identify end of a trace */
1254	BPF_STACK_BUILD_ID_EMPTY = 0,
1255	/* with valid build_id and offset */
1256	BPF_STACK_BUILD_ID_VALID = 1,
1257	/* couldn't get build_id, fallback to ip */
1258	BPF_STACK_BUILD_ID_IP = 2,
1259};
1260
1261#define BPF_BUILD_ID_SIZE 20
1262struct bpf_stack_build_id {
1263	__s32		status;
1264	unsigned char	build_id[BPF_BUILD_ID_SIZE];
1265	union {
1266		__u64	offset;
1267		__u64	ip;
1268	};
1269};
1270
1271#define BPF_OBJ_NAME_LEN 16U
1272
1273union bpf_attr {
1274	struct { /* anonymous struct used by BPF_MAP_CREATE command */
1275		__u32	map_type;	/* one of enum bpf_map_type */
1276		__u32	key_size;	/* size of key in bytes */
1277		__u32	value_size;	/* size of value in bytes */
1278		__u32	max_entries;	/* max number of entries in a map */
1279		__u32	map_flags;	/* BPF_MAP_CREATE related
1280					 * flags defined above.
1281					 */
1282		__u32	inner_map_fd;	/* fd pointing to the inner map */
1283		__u32	numa_node;	/* numa node (effective only if
1284					 * BPF_F_NUMA_NODE is set).
1285					 */
1286		char	map_name[BPF_OBJ_NAME_LEN];
1287		__u32	map_ifindex;	/* ifindex of netdev to create on */
1288		__u32	btf_fd;		/* fd pointing to a BTF type data */
1289		__u32	btf_key_type_id;	/* BTF type_id of the key */
1290		__u32	btf_value_type_id;	/* BTF type_id of the value */
1291		__u32	btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
1292						   * struct stored as the
1293						   * map value
1294						   */
1295		/* Any per-map-type extra fields
1296		 *
1297		 * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
1298		 * number of hash functions (if 0, the bloom filter will default
1299		 * to using 5 hash functions).
1300		 */
1301		__u64	map_extra;
1302	};
1303
1304	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
1305		__u32		map_fd;
1306		__aligned_u64	key;
1307		union {
1308			__aligned_u64 value;
1309			__aligned_u64 next_key;
1310		};
1311		__u64		flags;
1312	};
1313
1314	struct { /* struct used by BPF_MAP_*_BATCH commands */
1315		__aligned_u64	in_batch;	/* start batch,
1316						 * NULL to start from beginning
1317						 */
1318		__aligned_u64	out_batch;	/* output: next start batch */
1319		__aligned_u64	keys;
1320		__aligned_u64	values;
1321		__u32		count;		/* input/output:
1322						 * input: # of key/value
1323						 * elements
1324						 * output: # of filled elements
1325						 */
1326		__u32		map_fd;
1327		__u64		elem_flags;
1328		__u64		flags;
1329	} batch;
1330
1331	struct { /* anonymous struct used by BPF_PROG_LOAD command */
1332		__u32		prog_type;	/* one of enum bpf_prog_type */
1333		__u32		insn_cnt;
1334		__aligned_u64	insns;
1335		__aligned_u64	license;
1336		__u32		log_level;	/* verbosity level of verifier */
1337		__u32		log_size;	/* size of user buffer */
1338		__aligned_u64	log_buf;	/* user supplied buffer */
1339		__u32		kern_version;	/* not used */
1340		__u32		prog_flags;
1341		char		prog_name[BPF_OBJ_NAME_LEN];
1342		__u32		prog_ifindex;	/* ifindex of netdev to prep for */
1343		/* For some prog types expected attach type must be known at
1344		 * load time to verify attach type specific parts of prog
1345		 * (context accesses, allowed helpers, etc).
1346		 */
1347		__u32		expected_attach_type;
1348		__u32		prog_btf_fd;	/* fd pointing to BTF type data */
1349		__u32		func_info_rec_size;	/* userspace bpf_func_info size */
1350		__aligned_u64	func_info;	/* func info */
1351		__u32		func_info_cnt;	/* number of bpf_func_info records */
1352		__u32		line_info_rec_size;	/* userspace bpf_line_info size */
1353		__aligned_u64	line_info;	/* line info */
1354		__u32		line_info_cnt;	/* number of bpf_line_info records */
1355		__u32		attach_btf_id;	/* in-kernel BTF type id to attach to */
1356		union {
1357			/* valid prog_fd to attach to bpf prog */
1358			__u32		attach_prog_fd;
1359			/* or valid module BTF object fd or 0 to attach to vmlinux */
1360			__u32		attach_btf_obj_fd;
1361		};
1362		__u32		core_relo_cnt;	/* number of bpf_core_relo */
1363		__aligned_u64	fd_array;	/* array of FDs */
1364		__aligned_u64	core_relos;
1365		__u32		core_relo_rec_size; /* sizeof(struct bpf_core_relo) */
1366	};
1367
1368	struct { /* anonymous struct used by BPF_OBJ_* commands */
1369		__aligned_u64	pathname;
1370		__u32		bpf_fd;
1371		__u32		file_flags;
1372	};
1373
1374	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
1375		__u32		target_fd;	/* container object to attach to */
1376		__u32		attach_bpf_fd;	/* eBPF program to attach */
1377		__u32		attach_type;
1378		__u32		attach_flags;
1379		__u32		replace_bpf_fd;	/* previously attached eBPF
1380						 * program to replace if
1381						 * BPF_F_REPLACE is used
1382						 */
1383	};
1384
1385	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
1386		__u32		prog_fd;
1387		__u32		retval;
1388		__u32		data_size_in;	/* input: len of data_in */
1389		__u32		data_size_out;	/* input/output: len of data_out
1390						 *   returns ENOSPC if data_out
1391						 *   is too small.
1392						 */
1393		__aligned_u64	data_in;
1394		__aligned_u64	data_out;
1395		__u32		repeat;
1396		__u32		duration;
1397		__u32		ctx_size_in;	/* input: len of ctx_in */
1398		__u32		ctx_size_out;	/* input/output: len of ctx_out
1399						 *   returns ENOSPC if ctx_out
1400						 *   is too small.
1401						 */
1402		__aligned_u64	ctx_in;
1403		__aligned_u64	ctx_out;
1404		__u32		flags;
1405		__u32		cpu;
1406		__u32		batch_size;
1407	} test;
1408
1409	struct { /* anonymous struct used by BPF_*_GET_*_ID */
1410		union {
1411			__u32		start_id;
1412			__u32		prog_id;
1413			__u32		map_id;
1414			__u32		btf_id;
1415			__u32		link_id;
1416		};
1417		__u32		next_id;
1418		__u32		open_flags;
1419	};
1420
1421	struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
1422		__u32		bpf_fd;
1423		__u32		info_len;
1424		__aligned_u64	info;
1425	} info;
1426
1427	struct { /* anonymous struct used by BPF_PROG_QUERY command */
1428		__u32		target_fd;	/* container object to query */
1429		__u32		attach_type;
1430		__u32		query_flags;
1431		__u32		attach_flags;
1432		__aligned_u64	prog_ids;
1433		__u32		prog_cnt;
1434	} query;
1435
1436	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
1437		__u64 name;
1438		__u32 prog_fd;
1439	} raw_tracepoint;
1440
1441	struct { /* anonymous struct for BPF_BTF_LOAD */
1442		__aligned_u64	btf;
1443		__aligned_u64	btf_log_buf;
1444		__u32		btf_size;
1445		__u32		btf_log_size;
1446		__u32		btf_log_level;
1447	};
1448
1449	struct {
1450		__u32		pid;		/* input: pid */
1451		__u32		fd;		/* input: fd */
1452		__u32		flags;		/* input: flags */
1453		__u32		buf_len;	/* input/output: buf len */
1454		__aligned_u64	buf;		/* input/output:
1455						 *   tp_name for tracepoint
1456						 *   symbol for kprobe
1457						 *   filename for uprobe
1458						 */
1459		__u32		prog_id;	/* output: prod_id */
1460		__u32		fd_type;	/* output: BPF_FD_TYPE_* */
1461		__u64		probe_offset;	/* output: probe_offset */
1462		__u64		probe_addr;	/* output: probe_addr */
1463	} task_fd_query;
1464
1465	struct { /* struct used by BPF_LINK_CREATE command */
1466		__u32		prog_fd;	/* eBPF program to attach */
1467		union {
1468			__u32		target_fd;	/* object to attach to */
1469			__u32		target_ifindex; /* target ifindex */
1470		};
1471		__u32		attach_type;	/* attach type */
1472		__u32		flags;		/* extra flags */
1473		union {
1474			__u32		target_btf_id;	/* btf_id of target to attach to */
1475			struct {
1476				__aligned_u64	iter_info;	/* extra bpf_iter_link_info */
1477				__u32		iter_info_len;	/* iter_info length */
1478			};
1479			struct {
1480				/* black box user-provided value passed through
1481				 * to BPF program at the execution time and
1482				 * accessible through bpf_get_attach_cookie() BPF helper
1483				 */
1484				__u64		bpf_cookie;
1485			} perf_event;
1486			struct {
1487				__u32		flags;
1488				__u32		cnt;
1489				__aligned_u64	syms;
1490				__aligned_u64	addrs;
1491				__aligned_u64	cookies;
1492			} kprobe_multi;
1493			struct {
1494				/* this is overlaid with the target_btf_id above. */
1495				__u32		target_btf_id;
1496				/* black box user-provided value passed through
1497				 * to BPF program at the execution time and
1498				 * accessible through bpf_get_attach_cookie() BPF helper
1499				 */
1500				__u64		cookie;
1501			} tracing;
1502		};
1503	} link_create;
1504
1505	struct { /* struct used by BPF_LINK_UPDATE command */
1506		__u32		link_fd;	/* link fd */
1507		/* new program fd to update link with */
1508		__u32		new_prog_fd;
1509		__u32		flags;		/* extra flags */
1510		/* expected link's program fd; is specified only if
1511		 * BPF_F_REPLACE flag is set in flags */
1512		__u32		old_prog_fd;
1513	} link_update;
1514
1515	struct {
1516		__u32		link_fd;
1517	} link_detach;
1518
1519	struct { /* struct used by BPF_ENABLE_STATS command */
1520		__u32		type;
1521	} enable_stats;
1522
1523	struct { /* struct used by BPF_ITER_CREATE command */
1524		__u32		link_fd;
1525		__u32		flags;
1526	} iter_create;
1527
1528	struct { /* struct used by BPF_PROG_BIND_MAP command */
1529		__u32		prog_fd;
1530		__u32		map_fd;
1531		__u32		flags;		/* extra flags */
1532	} prog_bind_map;
1533
1534} __attribute__((aligned(8)));
1535
1536/* The description below is an attempt at providing documentation to eBPF
1537 * developers about the multiple available eBPF helper functions. It can be
1538 * parsed and used to produce a manual page. The workflow is the following,
1539 * and requires the rst2man utility:
1540 *
1541 *     $ ./scripts/bpf_doc.py \
1542 *             --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1543 *     $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1544 *     $ man /tmp/bpf-helpers.7
1545 *
1546 * Note that in order to produce this external documentation, some RST
1547 * formatting is used in the descriptions to get "bold" and "italics" in
1548 * manual pages. Also note that the few trailing white spaces are
1549 * intentional, removing them would break paragraphs for rst2man.
1550 *
1551 * Start of BPF helper function descriptions:
1552 *
1553 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
1554 * 	Description
1555 * 		Perform a lookup in *map* for an entry associated to *key*.
1556 * 	Return
1557 * 		Map value associated to *key*, or **NULL** if no entry was
1558 * 		found.
1559 *
1560 * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
1561 * 	Description
1562 * 		Add or update the value of the entry associated to *key* in
1563 * 		*map* with *value*. *flags* is one of:
1564 *
1565 * 		**BPF_NOEXIST**
1566 * 			The entry for *key* must not exist in the map.
1567 * 		**BPF_EXIST**
1568 * 			The entry for *key* must already exist in the map.
1569 * 		**BPF_ANY**
1570 * 			No condition on the existence of the entry for *key*.
1571 *
1572 * 		Flag value **BPF_NOEXIST** cannot be used for maps of types
1573 * 		**BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY**  (all
1574 * 		elements always exist), the helper would return an error.
1575 * 	Return
1576 * 		0 on success, or a negative error in case of failure.
1577 *
1578 * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
1579 * 	Description
1580 * 		Delete entry with *key* from *map*.
1581 * 	Return
1582 * 		0 on success, or a negative error in case of failure.
1583 *
1584 * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
1585 * 	Description
1586 * 		For tracing programs, safely attempt to read *size* bytes from
1587 * 		kernel space address *unsafe_ptr* and store the data in *dst*.
1588 *
1589 * 		Generally, use **bpf_probe_read_user**\ () or
1590 * 		**bpf_probe_read_kernel**\ () instead.
1591 * 	Return
1592 * 		0 on success, or a negative error in case of failure.
1593 *
1594 * u64 bpf_ktime_get_ns(void)
1595 * 	Description
1596 * 		Return the time elapsed since system boot, in nanoseconds.
1597 * 		Does not include time the system was suspended.
1598 * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
1599 * 	Return
1600 * 		Current *ktime*.
1601 *
1602 * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1603 * 	Description
1604 * 		This helper is a "printk()-like" facility for debugging. It
1605 * 		prints a message defined by format *fmt* (of size *fmt_size*)
1606 * 		to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
1607 * 		available. It can take up to three additional **u64**
1608 * 		arguments (as an eBPF helpers, the total number of arguments is
1609 * 		limited to five).
1610 *
1611 * 		Each time the helper is called, it appends a line to the trace.
1612 * 		Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
1613 * 		open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
1614 * 		The format of the trace is customizable, and the exact output
1615 * 		one will get depends on the options set in
1616 * 		*\/sys/kernel/debug/tracing/trace_options* (see also the
1617 * 		*README* file under the same directory). However, it usually
1618 * 		defaults to something like:
1619 *
1620 * 		::
1621 *
1622 * 			telnet-470   [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1623 *
1624 * 		In the above:
1625 *
1626 * 			* ``telnet`` is the name of the current task.
1627 * 			* ``470`` is the PID of the current task.
1628 * 			* ``001`` is the CPU number on which the task is
1629 * 			  running.
1630 * 			* In ``.N..``, each character refers to a set of
1631 * 			  options (whether irqs are enabled, scheduling
1632 * 			  options, whether hard/softirqs are running, level of
1633 * 			  preempt_disabled respectively). **N** means that
1634 * 			  **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
1635 * 			  are set.
1636 * 			* ``419421.045894`` is a timestamp.
1637 * 			* ``0x00000001`` is a fake value used by BPF for the
1638 * 			  instruction pointer register.
1639 * 			* ``<formatted msg>`` is the message formatted with
1640 * 			  *fmt*.
1641 *
1642 * 		The conversion specifiers supported by *fmt* are similar, but
1643 * 		more limited than for printk(). They are **%d**, **%i**,
1644 * 		**%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
1645 * 		**%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
1646 * 		of field, padding with zeroes, etc.) is available, and the
1647 * 		helper will return **-EINVAL** (but print nothing) if it
1648 * 		encounters an unknown specifier.
1649 *
1650 * 		Also, note that **bpf_trace_printk**\ () is slow, and should
1651 * 		only be used for debugging purposes. For this reason, a notice
1652 * 		block (spanning several lines) is printed to kernel logs and
1653 * 		states that the helper should not be used "for production use"
1654 * 		the first time this helper is used (or more precisely, when
1655 * 		**trace_printk**\ () buffers are allocated). For passing values
1656 * 		to user space, perf events should be preferred.
1657 * 	Return
1658 * 		The number of bytes written to the buffer, or a negative error
1659 * 		in case of failure.
1660 *
1661 * u32 bpf_get_prandom_u32(void)
1662 * 	Description
1663 * 		Get a pseudo-random number.
1664 *
1665 * 		From a security point of view, this helper uses its own
1666 * 		pseudo-random internal state, and cannot be used to infer the
1667 * 		seed of other random functions in the kernel. However, it is
1668 * 		essential to note that the generator used by the helper is not
1669 * 		cryptographically secure.
1670 * 	Return
1671 * 		A random 32-bit unsigned value.
1672 *
1673 * u32 bpf_get_smp_processor_id(void)
1674 * 	Description
1675 * 		Get the SMP (symmetric multiprocessing) processor id. Note that
1676 * 		all programs run with migration disabled, which means that the
1677 * 		SMP processor id is stable during all the execution of the
1678 * 		program.
1679 * 	Return
1680 * 		The SMP id of the processor running the program.
1681 *
1682 * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
1683 * 	Description
1684 * 		Store *len* bytes from address *from* into the packet
1685 * 		associated to *skb*, at *offset*. *flags* are a combination of
1686 * 		**BPF_F_RECOMPUTE_CSUM** (automatically recompute the
1687 * 		checksum for the packet after storing the bytes) and
1688 * 		**BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
1689 * 		**->swhash** and *skb*\ **->l4hash** to 0).
1690 *
1691 * 		A call to this helper is susceptible to change the underlying
1692 * 		packet buffer. Therefore, at load time, all checks on pointers
1693 * 		previously done by the verifier are invalidated and must be
1694 * 		performed again, if the helper is used in combination with
1695 * 		direct packet access.
1696 * 	Return
1697 * 		0 on success, or a negative error in case of failure.
1698 *
1699 * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1700 * 	Description
1701 * 		Recompute the layer 3 (e.g. IP) checksum for the packet
1702 * 		associated to *skb*. Computation is incremental, so the helper
1703 * 		must know the former value of the header field that was
1704 * 		modified (*from*), the new value of this field (*to*), and the
1705 * 		number of bytes (2 or 4) for this field, stored in *size*.
1706 * 		Alternatively, it is possible to store the difference between
1707 * 		the previous and the new values of the header field in *to*, by
1708 * 		setting *from* and *size* to 0. For both methods, *offset*
1709 * 		indicates the location of the IP checksum within the packet.
1710 *
1711 * 		This helper works in combination with **bpf_csum_diff**\ (),
1712 * 		which does not update the checksum in-place, but offers more
1713 * 		flexibility and can handle sizes larger than 2 or 4 for the
1714 * 		checksum to update.
1715 *
1716 * 		A call to this helper is susceptible to change the underlying
1717 * 		packet buffer. Therefore, at load time, all checks on pointers
1718 * 		previously done by the verifier are invalidated and must be
1719 * 		performed again, if the helper is used in combination with
1720 * 		direct packet access.
1721 * 	Return
1722 * 		0 on success, or a negative error in case of failure.
1723 *
1724 * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1725 * 	Description
1726 * 		Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1727 * 		packet associated to *skb*. Computation is incremental, so the
1728 * 		helper must know the former value of the header field that was
1729 * 		modified (*from*), the new value of this field (*to*), and the
1730 * 		number of bytes (2 or 4) for this field, stored on the lowest
1731 * 		four bits of *flags*. Alternatively, it is possible to store
1732 * 		the difference between the previous and the new values of the
1733 * 		header field in *to*, by setting *from* and the four lowest
1734 * 		bits of *flags* to 0. For both methods, *offset* indicates the
1735 * 		location of the IP checksum within the packet. In addition to
1736 * 		the size of the field, *flags* can be added (bitwise OR) actual
1737 * 		flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
1738 * 		untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
1739 * 		for updates resulting in a null checksum the value is set to
1740 * 		**CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
1741 * 		the checksum is to be computed against a pseudo-header.
1742 *
1743 * 		This helper works in combination with **bpf_csum_diff**\ (),
1744 * 		which does not update the checksum in-place, but offers more
1745 * 		flexibility and can handle sizes larger than 2 or 4 for the
1746 * 		checksum to update.
1747 *
1748 * 		A call to this helper is susceptible to change the underlying
1749 * 		packet buffer. Therefore, at load time, all checks on pointers
1750 * 		previously done by the verifier are invalidated and must be
1751 * 		performed again, if the helper is used in combination with
1752 * 		direct packet access.
1753 * 	Return
1754 * 		0 on success, or a negative error in case of failure.
1755 *
1756 * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
1757 * 	Description
1758 * 		This special helper is used to trigger a "tail call", or in
1759 * 		other words, to jump into another eBPF program. The same stack
1760 * 		frame is used (but values on stack and in registers for the
1761 * 		caller are not accessible to the callee). This mechanism allows
1762 * 		for program chaining, either for raising the maximum number of
1763 * 		available eBPF instructions, or to execute given programs in
1764 * 		conditional blocks. For security reasons, there is an upper
1765 * 		limit to the number of successive tail calls that can be
1766 * 		performed.
1767 *
1768 * 		Upon call of this helper, the program attempts to jump into a
1769 * 		program referenced at index *index* in *prog_array_map*, a
1770 * 		special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
1771 * 		*ctx*, a pointer to the context.
1772 *
1773 * 		If the call succeeds, the kernel immediately runs the first
1774 * 		instruction of the new program. This is not a function call,
1775 * 		and it never returns to the previous program. If the call
1776 * 		fails, then the helper has no effect, and the caller continues
1777 * 		to run its subsequent instructions. A call can fail if the
1778 * 		destination program for the jump does not exist (i.e. *index*
1779 * 		is superior to the number of entries in *prog_array_map*), or
1780 * 		if the maximum number of tail calls has been reached for this
1781 * 		chain of programs. This limit is defined in the kernel by the
1782 * 		macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
1783 *		which is currently set to 33.
1784 * 	Return
1785 * 		0 on success, or a negative error in case of failure.
1786 *
1787 * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1788 * 	Description
1789 * 		Clone and redirect the packet associated to *skb* to another
1790 * 		net device of index *ifindex*. Both ingress and egress
1791 * 		interfaces can be used for redirection. The **BPF_F_INGRESS**
1792 * 		value in *flags* is used to make the distinction (ingress path
1793 * 		is selected if the flag is present, egress path otherwise).
1794 * 		This is the only flag supported for now.
1795 *
1796 * 		In comparison with **bpf_redirect**\ () helper,
1797 * 		**bpf_clone_redirect**\ () has the associated cost of
1798 * 		duplicating the packet buffer, but this can be executed out of
1799 * 		the eBPF program. Conversely, **bpf_redirect**\ () is more
1800 * 		efficient, but it is handled through an action code where the
1801 * 		redirection happens only after the eBPF program has returned.
1802 *
1803 * 		A call to this helper is susceptible to change the underlying
1804 * 		packet buffer. Therefore, at load time, all checks on pointers
1805 * 		previously done by the verifier are invalidated and must be
1806 * 		performed again, if the helper is used in combination with
1807 * 		direct packet access.
1808 * 	Return
1809 * 		0 on success, or a negative error in case of failure.
1810 *
1811 * u64 bpf_get_current_pid_tgid(void)
1812 * 	Description
1813 * 		Get the current pid and tgid.
1814 * 	Return
1815 * 		A 64-bit integer containing the current tgid and pid, and
1816 * 		created as such:
1817 * 		*current_task*\ **->tgid << 32 \|**
1818 * 		*current_task*\ **->pid**.
1819 *
1820 * u64 bpf_get_current_uid_gid(void)
1821 * 	Description
1822 * 		Get the current uid and gid.
1823 * 	Return
1824 * 		A 64-bit integer containing the current GID and UID, and
1825 * 		created as such: *current_gid* **<< 32 \|** *current_uid*.
1826 *
1827 * long bpf_get_current_comm(void *buf, u32 size_of_buf)
1828 * 	Description
1829 * 		Copy the **comm** attribute of the current task into *buf* of
1830 * 		*size_of_buf*. The **comm** attribute contains the name of
1831 * 		the executable (excluding the path) for the current task. The
1832 * 		*size_of_buf* must be strictly positive. On success, the
1833 * 		helper makes sure that the *buf* is NUL-terminated. On failure,
1834 * 		it is filled with zeroes.
1835 * 	Return
1836 * 		0 on success, or a negative error in case of failure.
1837 *
1838 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1839 * 	Description
1840 * 		Retrieve the classid for the current task, i.e. for the net_cls
1841 * 		cgroup to which *skb* belongs.
1842 *
1843 * 		This helper can be used on TC egress path, but not on ingress.
1844 *
1845 * 		The net_cls cgroup provides an interface to tag network packets
1846 * 		based on a user-provided identifier for all traffic coming from
1847 * 		the tasks belonging to the related cgroup. See also the related
1848 * 		kernel documentation, available from the Linux sources in file
1849 * 		*Documentation/admin-guide/cgroup-v1/net_cls.rst*.
1850 *
1851 * 		The Linux kernel has two versions for cgroups: there are
1852 * 		cgroups v1 and cgroups v2. Both are available to users, who can
1853 * 		use a mixture of them, but note that the net_cls cgroup is for
1854 * 		cgroup v1 only. This makes it incompatible with BPF programs
1855 * 		run on cgroups, which is a cgroup-v2-only feature (a socket can
1856 * 		only hold data for one version of cgroups at a time).
1857 *
1858 * 		This helper is only available is the kernel was compiled with
1859 * 		the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
1860 * 		"**y**" or to "**m**".
1861 * 	Return
1862 * 		The classid, or 0 for the default unconfigured classid.
1863 *
1864 * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1865 * 	Description
1866 * 		Push a *vlan_tci* (VLAN tag control information) of protocol
1867 * 		*vlan_proto* to the packet associated to *skb*, then update
1868 * 		the checksum. Note that if *vlan_proto* is different from
1869 * 		**ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
1870 * 		be **ETH_P_8021Q**.
1871 *
1872 * 		A call to this helper is susceptible to change the underlying
1873 * 		packet buffer. Therefore, at load time, all checks on pointers
1874 * 		previously done by the verifier are invalidated and must be
1875 * 		performed again, if the helper is used in combination with
1876 * 		direct packet access.
1877 * 	Return
1878 * 		0 on success, or a negative error in case of failure.
1879 *
1880 * long bpf_skb_vlan_pop(struct sk_buff *skb)
1881 * 	Description
1882 * 		Pop a VLAN header from the packet associated to *skb*.
1883 *
1884 * 		A call to this helper is susceptible to change the underlying
1885 * 		packet buffer. Therefore, at load time, all checks on pointers
1886 * 		previously done by the verifier are invalidated and must be
1887 * 		performed again, if the helper is used in combination with
1888 * 		direct packet access.
1889 * 	Return
1890 * 		0 on success, or a negative error in case of failure.
1891 *
1892 * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1893 * 	Description
1894 * 		Get tunnel metadata. This helper takes a pointer *key* to an
1895 * 		empty **struct bpf_tunnel_key** of **size**, that will be
1896 * 		filled with tunnel metadata for the packet associated to *skb*.
1897 * 		The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
1898 * 		indicates that the tunnel is based on IPv6 protocol instead of
1899 * 		IPv4.
1900 *
1901 * 		The **struct bpf_tunnel_key** is an object that generalizes the
1902 * 		principal parameters used by various tunneling protocols into a
1903 * 		single struct. This way, it can be used to easily make a
1904 * 		decision based on the contents of the encapsulation header,
1905 * 		"summarized" in this struct. In particular, it holds the IP
1906 * 		address of the remote end (IPv4 or IPv6, depending on the case)
1907 * 		in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
1908 * 		this struct exposes the *key*\ **->tunnel_id**, which is
1909 * 		generally mapped to a VNI (Virtual Network Identifier), making
1910 * 		it programmable together with the **bpf_skb_set_tunnel_key**\
1911 * 		() helper.
1912 *
1913 * 		Let's imagine that the following code is part of a program
1914 * 		attached to the TC ingress interface, on one end of a GRE
1915 * 		tunnel, and is supposed to filter out all messages coming from
1916 * 		remote ends with IPv4 address other than 10.0.0.1:
1917 *
1918 * 		::
1919 *
1920 * 			int ret;
1921 * 			struct bpf_tunnel_key key = {};
1922 *
1923 * 			ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1924 * 			if (ret < 0)
1925 * 				return TC_ACT_SHOT;	// drop packet
1926 *
1927 * 			if (key.remote_ipv4 != 0x0a000001)
1928 * 				return TC_ACT_SHOT;	// drop packet
1929 *
1930 * 			return TC_ACT_OK;		// accept packet
1931 *
1932 * 		This interface can also be used with all encapsulation devices
1933 * 		that can operate in "collect metadata" mode: instead of having
1934 * 		one network device per specific configuration, the "collect
1935 * 		metadata" mode only requires a single device where the
1936 * 		configuration can be extracted from this helper.
1937 *
1938 * 		This can be used together with various tunnels such as VXLan,
1939 * 		Geneve, GRE or IP in IP (IPIP).
1940 * 	Return
1941 * 		0 on success, or a negative error in case of failure.
1942 *
1943 * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1944 * 	Description
1945 * 		Populate tunnel metadata for packet associated to *skb.* The
1946 * 		tunnel metadata is set to the contents of *key*, of *size*. The
1947 * 		*flags* can be set to a combination of the following values:
1948 *
1949 * 		**BPF_F_TUNINFO_IPV6**
1950 * 			Indicate that the tunnel is based on IPv6 protocol
1951 * 			instead of IPv4.
1952 * 		**BPF_F_ZERO_CSUM_TX**
1953 * 			For IPv4 packets, add a flag to tunnel metadata
1954 * 			indicating that checksum computation should be skipped
1955 * 			and checksum set to zeroes.
1956 * 		**BPF_F_DONT_FRAGMENT**
1957 * 			Add a flag to tunnel metadata indicating that the
1958 * 			packet should not be fragmented.
1959 * 		**BPF_F_SEQ_NUMBER**
1960 * 			Add a flag to tunnel metadata indicating that a
1961 * 			sequence number should be added to tunnel header before
1962 * 			sending the packet. This flag was added for GRE
1963 * 			encapsulation, but might be used with other protocols
1964 * 			as well in the future.
1965 *
1966 * 		Here is a typical usage on the transmit path:
1967 *
1968 * 		::
1969 *
1970 * 			struct bpf_tunnel_key key;
1971 * 			     populate key ...
1972 * 			bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
1973 * 			bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
1974 *
1975 * 		See also the description of the **bpf_skb_get_tunnel_key**\ ()
1976 * 		helper for additional information.
1977 * 	Return
1978 * 		0 on success, or a negative error in case of failure.
1979 *
1980 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
1981 * 	Description
1982 * 		Read the value of a perf event counter. This helper relies on a
1983 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
1984 * 		the perf event counter is selected when *map* is updated with
1985 * 		perf event file descriptors. The *map* is an array whose size
1986 * 		is the number of available CPUs, and each cell contains a value
1987 * 		relative to one CPU. The value to retrieve is indicated by
1988 * 		*flags*, that contains the index of the CPU to look up, masked
1989 * 		with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1990 * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
1991 * 		current CPU should be retrieved.
1992 *
1993 * 		Note that before Linux 4.13, only hardware perf event can be
1994 * 		retrieved.
1995 *
1996 * 		Also, be aware that the newer helper
1997 * 		**bpf_perf_event_read_value**\ () is recommended over
1998 * 		**bpf_perf_event_read**\ () in general. The latter has some ABI
1999 * 		quirks where error and counter value are used as a return code
2000 * 		(which is wrong to do since ranges may overlap). This issue is
2001 * 		fixed with **bpf_perf_event_read_value**\ (), which at the same
2002 * 		time provides more features over the **bpf_perf_event_read**\
2003 * 		() interface. Please refer to the description of
2004 * 		**bpf_perf_event_read_value**\ () for details.
2005 * 	Return
2006 * 		The value of the perf event counter read from the map, or a
2007 * 		negative error code in case of failure.
2008 *
2009 * long bpf_redirect(u32 ifindex, u64 flags)
2010 * 	Description
2011 * 		Redirect the packet to another net device of index *ifindex*.
2012 * 		This helper is somewhat similar to **bpf_clone_redirect**\
2013 * 		(), except that the packet is not cloned, which provides
2014 * 		increased performance.
2015 *
2016 * 		Except for XDP, both ingress and egress interfaces can be used
2017 * 		for redirection. The **BPF_F_INGRESS** value in *flags* is used
2018 * 		to make the distinction (ingress path is selected if the flag
2019 * 		is present, egress path otherwise). Currently, XDP only
2020 * 		supports redirection to the egress interface, and accepts no
2021 * 		flag at all.
2022 *
2023 * 		The same effect can also be attained with the more generic
2024 * 		**bpf_redirect_map**\ (), which uses a BPF map to store the
2025 * 		redirect target instead of providing it directly to the helper.
2026 * 	Return
2027 * 		For XDP, the helper returns **XDP_REDIRECT** on success or
2028 * 		**XDP_ABORTED** on error. For other program types, the values
2029 * 		are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
2030 * 		error.
2031 *
2032 * u32 bpf_get_route_realm(struct sk_buff *skb)
2033 * 	Description
2034 * 		Retrieve the realm or the route, that is to say the
2035 * 		**tclassid** field of the destination for the *skb*. The
2036 * 		identifier retrieved is a user-provided tag, similar to the
2037 * 		one used with the net_cls cgroup (see description for
2038 * 		**bpf_get_cgroup_classid**\ () helper), but here this tag is
2039 * 		held by a route (a destination entry), not by a task.
2040 *
2041 * 		Retrieving this identifier works with the clsact TC egress hook
2042 * 		(see also **tc-bpf(8)**), or alternatively on conventional
2043 * 		classful egress qdiscs, but not on TC ingress path. In case of
2044 * 		clsact TC egress hook, this has the advantage that, internally,
2045 * 		the destination entry has not been dropped yet in the transmit
2046 * 		path. Therefore, the destination entry does not need to be
2047 * 		artificially held via **netif_keep_dst**\ () for a classful
2048 * 		qdisc until the *skb* is freed.
2049 *
2050 * 		This helper is available only if the kernel was compiled with
2051 * 		**CONFIG_IP_ROUTE_CLASSID** configuration option.
2052 * 	Return
2053 * 		The realm of the route for the packet associated to *skb*, or 0
2054 * 		if none was found.
2055 *
2056 * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2057 * 	Description
2058 * 		Write raw *data* blob into a special BPF perf event held by
2059 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2060 * 		event must have the following attributes: **PERF_SAMPLE_RAW**
2061 * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2062 * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2063 *
2064 * 		The *flags* are used to indicate the index in *map* for which
2065 * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
2066 * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2067 * 		to indicate that the index of the current CPU core should be
2068 * 		used.
2069 *
2070 * 		The value to write, of *size*, is passed through eBPF stack and
2071 * 		pointed by *data*.
2072 *
2073 * 		The context of the program *ctx* needs also be passed to the
2074 * 		helper.
2075 *
2076 * 		On user space, a program willing to read the values needs to
2077 * 		call **perf_event_open**\ () on the perf event (either for
2078 * 		one or for all CPUs) and to store the file descriptor into the
2079 * 		*map*. This must be done before the eBPF program can send data
2080 * 		into it. An example is available in file
2081 * 		*samples/bpf/trace_output_user.c* in the Linux kernel source
2082 * 		tree (the eBPF program counterpart is in
2083 * 		*samples/bpf/trace_output_kern.c*).
2084 *
2085 * 		**bpf_perf_event_output**\ () achieves better performance
2086 * 		than **bpf_trace_printk**\ () for sharing data with user
2087 * 		space, and is much better suitable for streaming data from eBPF
2088 * 		programs.
2089 *
2090 * 		Note that this helper is not restricted to tracing use cases
2091 * 		and can be used with programs attached to TC or XDP as well,
2092 * 		where it allows for passing data to user space listeners. Data
2093 * 		can be:
2094 *
2095 * 		* Only custom structs,
2096 * 		* Only the packet payload, or
2097 * 		* A combination of both.
2098 * 	Return
2099 * 		0 on success, or a negative error in case of failure.
2100 *
2101 * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
2102 * 	Description
2103 * 		This helper was provided as an easy way to load data from a
2104 * 		packet. It can be used to load *len* bytes from *offset* from
2105 * 		the packet associated to *skb*, into the buffer pointed by
2106 * 		*to*.
2107 *
2108 * 		Since Linux 4.7, usage of this helper has mostly been replaced
2109 * 		by "direct packet access", enabling packet data to be
2110 * 		manipulated with *skb*\ **->data** and *skb*\ **->data_end**
2111 * 		pointing respectively to the first byte of packet data and to
2112 * 		the byte after the last byte of packet data. However, it
2113 * 		remains useful if one wishes to read large quantities of data
2114 * 		at once from a packet into the eBPF stack.
2115 * 	Return
2116 * 		0 on success, or a negative error in case of failure.
2117 *
2118 * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
2119 * 	Description
2120 * 		Walk a user or a kernel stack and return its id. To achieve
2121 * 		this, the helper needs *ctx*, which is a pointer to the context
2122 * 		on which the tracing program is executed, and a pointer to a
2123 * 		*map* of type **BPF_MAP_TYPE_STACK_TRACE**.
2124 *
2125 * 		The last argument, *flags*, holds the number of stack frames to
2126 * 		skip (from 0 to 255), masked with
2127 * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2128 * 		a combination of the following flags:
2129 *
2130 * 		**BPF_F_USER_STACK**
2131 * 			Collect a user space stack instead of a kernel stack.
2132 * 		**BPF_F_FAST_STACK_CMP**
2133 * 			Compare stacks by hash only.
2134 * 		**BPF_F_REUSE_STACKID**
2135 * 			If two different stacks hash into the same *stackid*,
2136 * 			discard the old one.
2137 *
2138 * 		The stack id retrieved is a 32 bit long integer handle which
2139 * 		can be further combined with other data (including other stack
2140 * 		ids) and used as a key into maps. This can be useful for
2141 * 		generating a variety of graphs (such as flame graphs or off-cpu
2142 * 		graphs).
2143 *
2144 * 		For walking a stack, this helper is an improvement over
2145 * 		**bpf_probe_read**\ (), which can be used with unrolled loops
2146 * 		but is not efficient and consumes a lot of eBPF instructions.
2147 * 		Instead, **bpf_get_stackid**\ () can collect up to
2148 * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
2149 * 		this limit can be controlled with the **sysctl** program, and
2150 * 		that it should be manually increased in order to profile long
2151 * 		user stacks (such as stacks for Java programs). To do so, use:
2152 *
2153 * 		::
2154 *
2155 * 			# sysctl kernel.perf_event_max_stack=<new value>
2156 * 	Return
2157 * 		The positive or null stack id on success, or a negative error
2158 * 		in case of failure.
2159 *
2160 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
2161 * 	Description
2162 * 		Compute a checksum difference, from the raw buffer pointed by
2163 * 		*from*, of length *from_size* (that must be a multiple of 4),
2164 * 		towards the raw buffer pointed by *to*, of size *to_size*
2165 * 		(same remark). An optional *seed* can be added to the value
2166 * 		(this can be cascaded, the seed may come from a previous call
2167 * 		to the helper).
2168 *
2169 * 		This is flexible enough to be used in several ways:
2170 *
2171 * 		* With *from_size* == 0, *to_size* > 0 and *seed* set to
2172 * 		  checksum, it can be used when pushing new data.
2173 * 		* With *from_size* > 0, *to_size* == 0 and *seed* set to
2174 * 		  checksum, it can be used when removing data from a packet.
2175 * 		* With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
2176 * 		  can be used to compute a diff. Note that *from_size* and
2177 * 		  *to_size* do not need to be equal.
2178 *
2179 * 		This helper can be used in combination with
2180 * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
2181 * 		which one can feed in the difference computed with
2182 * 		**bpf_csum_diff**\ ().
2183 * 	Return
2184 * 		The checksum result, or a negative error code in case of
2185 * 		failure.
2186 *
2187 * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2188 * 	Description
2189 * 		Retrieve tunnel options metadata for the packet associated to
2190 * 		*skb*, and store the raw tunnel option data to the buffer *opt*
2191 * 		of *size*.
2192 *
2193 * 		This helper can be used with encapsulation devices that can
2194 * 		operate in "collect metadata" mode (please refer to the related
2195 * 		note in the description of **bpf_skb_get_tunnel_key**\ () for
2196 * 		more details). A particular example where this can be used is
2197 * 		in combination with the Geneve encapsulation protocol, where it
2198 * 		allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
2199 * 		and retrieving arbitrary TLVs (Type-Length-Value headers) from
2200 * 		the eBPF program. This allows for full customization of these
2201 * 		headers.
2202 * 	Return
2203 * 		The size of the option data retrieved.
2204 *
2205 * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2206 * 	Description
2207 * 		Set tunnel options metadata for the packet associated to *skb*
2208 * 		to the option data contained in the raw buffer *opt* of *size*.
2209 *
2210 * 		See also the description of the **bpf_skb_get_tunnel_opt**\ ()
2211 * 		helper for additional information.
2212 * 	Return
2213 * 		0 on success, or a negative error in case of failure.
2214 *
2215 * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2216 * 	Description
2217 * 		Change the protocol of the *skb* to *proto*. Currently
2218 * 		supported are transition from IPv4 to IPv6, and from IPv6 to
2219 * 		IPv4. The helper takes care of the groundwork for the
2220 * 		transition, including resizing the socket buffer. The eBPF
2221 * 		program is expected to fill the new headers, if any, via
2222 * 		**skb_store_bytes**\ () and to recompute the checksums with
2223 * 		**bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
2224 * 		(). The main case for this helper is to perform NAT64
2225 * 		operations out of an eBPF program.
2226 *
2227 * 		Internally, the GSO type is marked as dodgy so that headers are
2228 * 		checked and segments are recalculated by the GSO/GRO engine.
2229 * 		The size for GSO target is adapted as well.
2230 *
2231 * 		All values for *flags* are reserved for future usage, and must
2232 * 		be left at zero.
2233 *
2234 * 		A call to this helper is susceptible to change the underlying
2235 * 		packet buffer. Therefore, at load time, all checks on pointers
2236 * 		previously done by the verifier are invalidated and must be
2237 * 		performed again, if the helper is used in combination with
2238 * 		direct packet access.
2239 * 	Return
2240 * 		0 on success, or a negative error in case of failure.
2241 *
2242 * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2243 * 	Description
2244 * 		Change the packet type for the packet associated to *skb*. This
2245 * 		comes down to setting *skb*\ **->pkt_type** to *type*, except
2246 * 		the eBPF program does not have a write access to *skb*\
2247 * 		**->pkt_type** beside this helper. Using a helper here allows
2248 * 		for graceful handling of errors.
2249 *
2250 * 		The major use case is to change incoming *skb*s to
2251 * 		**PACKET_HOST** in a programmatic way instead of having to
2252 * 		recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
2253 * 		example.
2254 *
2255 * 		Note that *type* only allows certain values. At this time, they
2256 * 		are:
2257 *
2258 * 		**PACKET_HOST**
2259 * 			Packet is for us.
2260 * 		**PACKET_BROADCAST**
2261 * 			Send packet to all.
2262 * 		**PACKET_MULTICAST**
2263 * 			Send packet to group.
2264 * 		**PACKET_OTHERHOST**
2265 * 			Send packet to someone else.
2266 * 	Return
2267 * 		0 on success, or a negative error in case of failure.
2268 *
2269 * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
2270 * 	Description
2271 * 		Check whether *skb* is a descendant of the cgroup2 held by
2272 * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2273 * 	Return
2274 * 		The return value depends on the result of the test, and can be:
2275 *
2276 * 		* 0, if the *skb* failed the cgroup2 descendant test.
2277 * 		* 1, if the *skb* succeeded the cgroup2 descendant test.
2278 * 		* A negative error code, if an error occurred.
2279 *
2280 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
2281 * 	Description
2282 * 		Retrieve the hash of the packet, *skb*\ **->hash**. If it is
2283 * 		not set, in particular if the hash was cleared due to mangling,
2284 * 		recompute this hash. Later accesses to the hash can be done
2285 * 		directly with *skb*\ **->hash**.
2286 *
2287 * 		Calling **bpf_set_hash_invalid**\ (), changing a packet
2288 * 		prototype with **bpf_skb_change_proto**\ (), or calling
2289 * 		**bpf_skb_store_bytes**\ () with the
2290 * 		**BPF_F_INVALIDATE_HASH** are actions susceptible to clear
2291 * 		the hash and to trigger a new computation for the next call to
2292 * 		**bpf_get_hash_recalc**\ ().
2293 * 	Return
2294 * 		The 32-bit hash.
2295 *
2296 * u64 bpf_get_current_task(void)
2297 * 	Description
2298 * 		Get the current task.
2299 * 	Return
2300 * 		A pointer to the current task struct.
2301 *
2302 * long bpf_probe_write_user(void *dst, const void *src, u32 len)
2303 * 	Description
2304 * 		Attempt in a safe way to write *len* bytes from the buffer
2305 * 		*src* to *dst* in memory. It only works for threads that are in
2306 * 		user context, and *dst* must be a valid user space address.
2307 *
2308 * 		This helper should not be used to implement any kind of
2309 * 		security mechanism because of TOC-TOU attacks, but rather to
2310 * 		debug, divert, and manipulate execution of semi-cooperative
2311 * 		processes.
2312 *
2313 * 		Keep in mind that this feature is meant for experiments, and it
2314 * 		has a risk of crashing the system and running programs.
2315 * 		Therefore, when an eBPF program using this helper is attached,
2316 * 		a warning including PID and process name is printed to kernel
2317 * 		logs.
2318 * 	Return
2319 * 		0 on success, or a negative error in case of failure.
2320 *
2321 * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2322 * 	Description
2323 * 		Check whether the probe is being run is the context of a given
2324 * 		subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2325 * 		*map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2326 * 	Return
2327 * 		The return value depends on the result of the test, and can be:
2328 *
2329 *		* 1, if current task belongs to the cgroup2.
2330 *		* 0, if current task does not belong to the cgroup2.
2331 * 		* A negative error code, if an error occurred.
2332 *
2333 * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2334 * 	Description
2335 * 		Resize (trim or grow) the packet associated to *skb* to the
2336 * 		new *len*. The *flags* are reserved for future usage, and must
2337 * 		be left at zero.
2338 *
2339 * 		The basic idea is that the helper performs the needed work to
2340 * 		change the size of the packet, then the eBPF program rewrites
2341 * 		the rest via helpers like **bpf_skb_store_bytes**\ (),
2342 * 		**bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
2343 * 		and others. This helper is a slow path utility intended for
2344 * 		replies with control messages. And because it is targeted for
2345 * 		slow path, the helper itself can afford to be slow: it
2346 * 		implicitly linearizes, unclones and drops offloads from the
2347 * 		*skb*.
2348 *
2349 * 		A call to this helper is susceptible to change the underlying
2350 * 		packet buffer. Therefore, at load time, all checks on pointers
2351 * 		previously done by the verifier are invalidated and must be
2352 * 		performed again, if the helper is used in combination with
2353 * 		direct packet access.
2354 * 	Return
2355 * 		0 on success, or a negative error in case of failure.
2356 *
2357 * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2358 * 	Description
2359 * 		Pull in non-linear data in case the *skb* is non-linear and not
2360 * 		all of *len* are part of the linear section. Make *len* bytes
2361 * 		from *skb* readable and writable. If a zero value is passed for
2362 * 		*len*, then the whole length of the *skb* is pulled.
2363 *
2364 * 		This helper is only needed for reading and writing with direct
2365 * 		packet access.
2366 *
2367 * 		For direct packet access, testing that offsets to access
2368 * 		are within packet boundaries (test on *skb*\ **->data_end**) is
2369 * 		susceptible to fail if offsets are invalid, or if the requested
2370 * 		data is in non-linear parts of the *skb*. On failure the
2371 * 		program can just bail out, or in the case of a non-linear
2372 * 		buffer, use a helper to make the data available. The
2373 * 		**bpf_skb_load_bytes**\ () helper is a first solution to access
2374 * 		the data. Another one consists in using **bpf_skb_pull_data**
2375 * 		to pull in once the non-linear parts, then retesting and
2376 * 		eventually access the data.
2377 *
2378 * 		At the same time, this also makes sure the *skb* is uncloned,
2379 * 		which is a necessary condition for direct write. As this needs
2380 * 		to be an invariant for the write part only, the verifier
2381 * 		detects writes and adds a prologue that is calling
2382 * 		**bpf_skb_pull_data()** to effectively unclone the *skb* from
2383 * 		the very beginning in case it is indeed cloned.
2384 *
2385 * 		A call to this helper is susceptible to change the underlying
2386 * 		packet buffer. Therefore, at load time, all checks on pointers
2387 * 		previously done by the verifier are invalidated and must be
2388 * 		performed again, if the helper is used in combination with
2389 * 		direct packet access.
2390 * 	Return
2391 * 		0 on success, or a negative error in case of failure.
2392 *
2393 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2394 * 	Description
2395 * 		Add the checksum *csum* into *skb*\ **->csum** in case the
2396 * 		driver has supplied a checksum for the entire packet into that
2397 * 		field. Return an error otherwise. This helper is intended to be
2398 * 		used in combination with **bpf_csum_diff**\ (), in particular
2399 * 		when the checksum needs to be updated after data has been
2400 * 		written into the packet through direct packet access.
2401 * 	Return
2402 * 		The checksum on success, or a negative error code in case of
2403 * 		failure.
2404 *
2405 * void bpf_set_hash_invalid(struct sk_buff *skb)
2406 * 	Description
2407 * 		Invalidate the current *skb*\ **->hash**. It can be used after
2408 * 		mangling on headers through direct packet access, in order to
2409 * 		indicate that the hash is outdated and to trigger a
2410 * 		recalculation the next time the kernel tries to access this
2411 * 		hash or when the **bpf_get_hash_recalc**\ () helper is called.
2412 * 	Return
2413 * 		void.
2414 *
2415 * long bpf_get_numa_node_id(void)
2416 * 	Description
2417 * 		Return the id of the current NUMA node. The primary use case
2418 * 		for this helper is the selection of sockets for the local NUMA
2419 * 		node, when the program is attached to sockets using the
2420 * 		**SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
2421 * 		but the helper is also available to other eBPF program types,
2422 * 		similarly to **bpf_get_smp_processor_id**\ ().
2423 * 	Return
2424 * 		The id of current NUMA node.
2425 *
2426 * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2427 * 	Description
2428 * 		Grows headroom of packet associated to *skb* and adjusts the
2429 * 		offset of the MAC header accordingly, adding *len* bytes of
2430 * 		space. It automatically extends and reallocates memory as
2431 * 		required.
2432 *
2433 * 		This helper can be used on a layer 3 *skb* to push a MAC header
2434 * 		for redirection into a layer 2 device.
2435 *
2436 * 		All values for *flags* are reserved for future usage, and must
2437 * 		be left at zero.
2438 *
2439 * 		A call to this helper is susceptible to change the underlying
2440 * 		packet buffer. Therefore, at load time, all checks on pointers
2441 * 		previously done by the verifier are invalidated and must be
2442 * 		performed again, if the helper is used in combination with
2443 * 		direct packet access.
2444 * 	Return
2445 * 		0 on success, or a negative error in case of failure.
2446 *
2447 * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2448 * 	Description
2449 * 		Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
2450 * 		it is possible to use a negative value for *delta*. This helper
2451 * 		can be used to prepare the packet for pushing or popping
2452 * 		headers.
2453 *
2454 * 		A call to this helper is susceptible to change the underlying
2455 * 		packet buffer. Therefore, at load time, all checks on pointers
2456 * 		previously done by the verifier are invalidated and must be
2457 * 		performed again, if the helper is used in combination with
2458 * 		direct packet access.
2459 * 	Return
2460 * 		0 on success, or a negative error in case of failure.
2461 *
2462 * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
2463 * 	Description
2464 * 		Copy a NUL terminated string from an unsafe kernel address
2465 * 		*unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
2466 * 		more details.
2467 *
2468 * 		Generally, use **bpf_probe_read_user_str**\ () or
2469 * 		**bpf_probe_read_kernel_str**\ () instead.
2470 * 	Return
2471 * 		On success, the strictly positive length of the string,
2472 * 		including the trailing NUL character. On error, a negative
2473 * 		value.
2474 *
2475 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
2476 * 	Description
2477 * 		If the **struct sk_buff** pointed by *skb* has a known socket,
2478 * 		retrieve the cookie (generated by the kernel) of this socket.
2479 * 		If no cookie has been set yet, generate a new cookie. Once
2480 * 		generated, the socket cookie remains stable for the life of the
2481 * 		socket. This helper can be useful for monitoring per socket
2482 * 		networking traffic statistics as it provides a global socket
2483 * 		identifier that can be assumed unique.
2484 * 	Return
2485 * 		A 8-byte long unique number on success, or 0 if the socket
2486 * 		field is missing inside *skb*.
2487 *
2488 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2489 * 	Description
2490 * 		Equivalent to bpf_get_socket_cookie() helper that accepts
2491 * 		*skb*, but gets socket from **struct bpf_sock_addr** context.
2492 * 	Return
2493 * 		A 8-byte long unique number.
2494 *
2495 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2496 * 	Description
2497 * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2498 * 		*skb*, but gets socket from **struct bpf_sock_ops** context.
2499 * 	Return
2500 * 		A 8-byte long unique number.
2501 *
2502 * u64 bpf_get_socket_cookie(struct sock *sk)
2503 * 	Description
2504 * 		Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2505 * 		*sk*, but gets socket from a BTF **struct sock**. This helper
2506 * 		also works for sleepable programs.
2507 * 	Return
2508 * 		A 8-byte long unique number or 0 if *sk* is NULL.
2509 *
2510 * u32 bpf_get_socket_uid(struct sk_buff *skb)
2511 * 	Description
2512 * 		Get the owner UID of the socked associated to *skb*.
2513 * 	Return
2514 * 		The owner UID of the socket associated to *skb*. If the socket
2515 * 		is **NULL**, or if it is not a full socket (i.e. if it is a
2516 * 		time-wait or a request socket instead), **overflowuid** value
2517 * 		is returned (note that **overflowuid** might also be the actual
2518 * 		UID value for the socket).
2519 *
2520 * long bpf_set_hash(struct sk_buff *skb, u32 hash)
2521 * 	Description
2522 * 		Set the full hash for *skb* (set the field *skb*\ **->hash**)
2523 * 		to value *hash*.
2524 * 	Return
2525 * 		0
2526 *
2527 * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2528 * 	Description
2529 * 		Emulate a call to **setsockopt()** on the socket associated to
2530 * 		*bpf_socket*, which must be a full socket. The *level* at
2531 * 		which the option resides and the name *optname* of the option
2532 * 		must be specified, see **setsockopt(2)** for more information.
2533 * 		The option value of length *optlen* is pointed by *optval*.
2534 *
2535 * 		*bpf_socket* should be one of the following:
2536 *
2537 * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2538 * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2539 * 		  and **BPF_CGROUP_INET6_CONNECT**.
2540 *
2541 * 		This helper actually implements a subset of **setsockopt()**.
2542 * 		It supports the following *level*\ s:
2543 *
2544 * 		* **SOL_SOCKET**, which supports the following *optname*\ s:
2545 * 		  **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
2546 * 		  **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
2547 * 		  **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
2548 * 		* **IPPROTO_TCP**, which supports the following *optname*\ s:
2549 * 		  **TCP_CONGESTION**, **TCP_BPF_IW**,
2550 * 		  **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
2551 * 		  **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
2552 *		  **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
2553 * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2554 * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2555 * 	Return
2556 * 		0 on success, or a negative error in case of failure.
2557 *
2558 * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2559 * 	Description
2560 * 		Grow or shrink the room for data in the packet associated to
2561 * 		*skb* by *len_diff*, and according to the selected *mode*.
2562 *
2563 * 		By default, the helper will reset any offloaded checksum
2564 * 		indicator of the skb to CHECKSUM_NONE. This can be avoided
2565 * 		by the following flag:
2566 *
2567 * 		* **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
2568 * 		  checksum data of the skb to CHECKSUM_NONE.
2569 *
2570 *		There are two supported modes at this time:
2571 *
2572 *		* **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
2573 *		  (room space is added or removed below the layer 2 header).
2574 *
2575 * 		* **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
2576 * 		  (room space is added or removed below the layer 3 header).
2577 *
2578 *		The following flags are supported at this time:
2579 *
2580 *		* **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
2581 *		  Adjusting mss in this way is not allowed for datagrams.
2582 *
2583 *		* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
2584 *		  **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
2585 *		  Any new space is reserved to hold a tunnel header.
2586 *		  Configure skb offsets and other fields accordingly.
2587 *
2588 *		* **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
2589 *		  **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
2590 *		  Use with ENCAP_L3 flags to further specify the tunnel type.
2591 *
2592 *		* **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
2593 *		  Use with ENCAP_L3/L4 flags to further specify the tunnel
2594 *		  type; *len* is the length of the inner MAC header.
2595 *
2596 *		* **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
2597 *		  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2598 *		  L2 type as Ethernet.
2599 *
2600 * 		A call to this helper is susceptible to change the underlying
2601 * 		packet buffer. Therefore, at load time, all checks on pointers
2602 * 		previously done by the verifier are invalidated and must be
2603 * 		performed again, if the helper is used in combination with
2604 * 		direct packet access.
2605 * 	Return
2606 * 		0 on success, or a negative error in case of failure.
2607 *
2608 * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2609 * 	Description
2610 * 		Redirect the packet to the endpoint referenced by *map* at
2611 * 		index *key*. Depending on its type, this *map* can contain
2612 * 		references to net devices (for forwarding packets through other
2613 * 		ports), or to CPUs (for redirecting XDP frames to another CPU;
2614 * 		but this is only implemented for native XDP (with driver
2615 * 		support) as of this writing).
2616 *
2617 * 		The lower two bits of *flags* are used as the return code if
2618 * 		the map lookup fails. This is so that the return value can be
2619 * 		one of the XDP program return codes up to **XDP_TX**, as chosen
2620 * 		by the caller. The higher bits of *flags* can be set to
2621 * 		BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2622 *
2623 * 		With BPF_F_BROADCAST the packet will be broadcasted to all the
2624 * 		interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2625 * 		interface will be excluded when do broadcasting.
2626 *
2627 * 		See also **bpf_redirect**\ (), which only supports redirecting
2628 * 		to an ifindex, but doesn't require a map to do so.
2629 * 	Return
2630 * 		**XDP_REDIRECT** on success, or the value of the two lower bits
2631 * 		of the *flags* argument on error.
2632 *
2633 * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
2634 * 	Description
2635 * 		Redirect the packet to the socket referenced by *map* (of type
2636 * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2637 * 		egress interfaces can be used for redirection. The
2638 * 		**BPF_F_INGRESS** value in *flags* is used to make the
2639 * 		distinction (ingress path is selected if the flag is present,
2640 * 		egress path otherwise). This is the only flag supported for now.
2641 * 	Return
2642 * 		**SK_PASS** on success, or **SK_DROP** on error.
2643 *
2644 * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2645 * 	Description
2646 * 		Add an entry to, or update a *map* referencing sockets. The
2647 * 		*skops* is used as a new value for the entry associated to
2648 * 		*key*. *flags* is one of:
2649 *
2650 * 		**BPF_NOEXIST**
2651 * 			The entry for *key* must not exist in the map.
2652 * 		**BPF_EXIST**
2653 * 			The entry for *key* must already exist in the map.
2654 * 		**BPF_ANY**
2655 * 			No condition on the existence of the entry for *key*.
2656 *
2657 * 		If the *map* has eBPF programs (parser and verdict), those will
2658 * 		be inherited by the socket being added. If the socket is
2659 * 		already attached to eBPF programs, this results in an error.
2660 * 	Return
2661 * 		0 on success, or a negative error in case of failure.
2662 *
2663 * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2664 * 	Description
2665 * 		Adjust the address pointed by *xdp_md*\ **->data_meta** by
2666 * 		*delta* (which can be positive or negative). Note that this
2667 * 		operation modifies the address stored in *xdp_md*\ **->data**,
2668 * 		so the latter must be loaded only after the helper has been
2669 * 		called.
2670 *
2671 * 		The use of *xdp_md*\ **->data_meta** is optional and programs
2672 * 		are not required to use it. The rationale is that when the
2673 * 		packet is processed with XDP (e.g. as DoS filter), it is
2674 * 		possible to push further meta data along with it before passing
2675 * 		to the stack, and to give the guarantee that an ingress eBPF
2676 * 		program attached as a TC classifier on the same device can pick
2677 * 		this up for further post-processing. Since TC works with socket
2678 * 		buffers, it remains possible to set from XDP the **mark** or
2679 * 		**priority** pointers, or other pointers for the socket buffer.
2680 * 		Having this scratch space generic and programmable allows for
2681 * 		more flexibility as the user is free to store whatever meta
2682 * 		data they need.
2683 *
2684 * 		A call to this helper is susceptible to change the underlying
2685 * 		packet buffer. Therefore, at load time, all checks on pointers
2686 * 		previously done by the verifier are invalidated and must be
2687 * 		performed again, if the helper is used in combination with
2688 * 		direct packet access.
2689 * 	Return
2690 * 		0 on success, or a negative error in case of failure.
2691 *
2692 * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
2693 * 	Description
2694 * 		Read the value of a perf event counter, and store it into *buf*
2695 * 		of size *buf_size*. This helper relies on a *map* of type
2696 * 		**BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
2697 * 		counter is selected when *map* is updated with perf event file
2698 * 		descriptors. The *map* is an array whose size is the number of
2699 * 		available CPUs, and each cell contains a value relative to one
2700 * 		CPU. The value to retrieve is indicated by *flags*, that
2701 * 		contains the index of the CPU to look up, masked with
2702 * 		**BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2703 * 		**BPF_F_CURRENT_CPU** to indicate that the value for the
2704 * 		current CPU should be retrieved.
2705 *
2706 * 		This helper behaves in a way close to
2707 * 		**bpf_perf_event_read**\ () helper, save that instead of
2708 * 		just returning the value observed, it fills the *buf*
2709 * 		structure. This allows for additional data to be retrieved: in
2710 * 		particular, the enabled and running times (in *buf*\
2711 * 		**->enabled** and *buf*\ **->running**, respectively) are
2712 * 		copied. In general, **bpf_perf_event_read_value**\ () is
2713 * 		recommended over **bpf_perf_event_read**\ (), which has some
2714 * 		ABI issues and provides fewer functionalities.
2715 *
2716 * 		These values are interesting, because hardware PMU (Performance
2717 * 		Monitoring Unit) counters are limited resources. When there are
2718 * 		more PMU based perf events opened than available counters,
2719 * 		kernel will multiplex these events so each event gets certain
2720 * 		percentage (but not all) of the PMU time. In case that
2721 * 		multiplexing happens, the number of samples or counter value
2722 * 		will not reflect the case compared to when no multiplexing
2723 * 		occurs. This makes comparison between different runs difficult.
2724 * 		Typically, the counter value should be normalized before
2725 * 		comparing to other experiments. The usual normalization is done
2726 * 		as follows.
2727 *
2728 * 		::
2729 *
2730 * 			normalized_counter = counter * t_enabled / t_running
2731 *
2732 * 		Where t_enabled is the time enabled for event and t_running is
2733 * 		the time running for event since last normalization. The
2734 * 		enabled and running times are accumulated since the perf event
2735 * 		open. To achieve scaling factor between two invocations of an
2736 * 		eBPF program, users can use CPU id as the key (which is
2737 * 		typical for perf array usage model) to remember the previous
2738 * 		value and do the calculation inside the eBPF program.
2739 * 	Return
2740 * 		0 on success, or a negative error in case of failure.
2741 *
2742 * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
2743 * 	Description
2744 * 		For en eBPF program attached to a perf event, retrieve the
2745 * 		value of the event counter associated to *ctx* and store it in
2746 * 		the structure pointed by *buf* and of size *buf_size*. Enabled
2747 * 		and running times are also stored in the structure (see
2748 * 		description of helper **bpf_perf_event_read_value**\ () for
2749 * 		more details).
2750 * 	Return
2751 * 		0 on success, or a negative error in case of failure.
2752 *
2753 * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2754 * 	Description
2755 * 		Emulate a call to **getsockopt()** on the socket associated to
2756 * 		*bpf_socket*, which must be a full socket. The *level* at
2757 * 		which the option resides and the name *optname* of the option
2758 * 		must be specified, see **getsockopt(2)** for more information.
2759 * 		The retrieved value is stored in the structure pointed by
2760 * 		*opval* and of length *optlen*.
2761 *
2762 * 		*bpf_socket* should be one of the following:
2763 *
2764 * 		* **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2765 * 		* **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2766 * 		  and **BPF_CGROUP_INET6_CONNECT**.
2767 *
2768 * 		This helper actually implements a subset of **getsockopt()**.
2769 * 		It supports the following *level*\ s:
2770 *
2771 * 		* **IPPROTO_TCP**, which supports *optname*
2772 * 		  **TCP_CONGESTION**.
2773 * 		* **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2774 * 		* **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2775 * 	Return
2776 * 		0 on success, or a negative error in case of failure.
2777 *
2778 * long bpf_override_return(struct pt_regs *regs, u64 rc)
2779 * 	Description
2780 * 		Used for error injection, this helper uses kprobes to override
2781 * 		the return value of the probed function, and to set it to *rc*.
2782 * 		The first argument is the context *regs* on which the kprobe
2783 * 		works.
2784 *
2785 * 		This helper works by setting the PC (program counter)
2786 * 		to an override function which is run in place of the original
2787 * 		probed function. This means the probed function is not run at
2788 * 		all. The replacement function just returns with the required
2789 * 		value.
2790 *
2791 * 		This helper has security implications, and thus is subject to
2792 * 		restrictions. It is only available if the kernel was compiled
2793 * 		with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
2794 * 		option, and in this case it only works on functions tagged with
2795 * 		**ALLOW_ERROR_INJECTION** in the kernel code.
2796 *
2797 * 		Also, the helper is only available for the architectures having
2798 * 		the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2799 * 		x86 architecture is the only one to support this feature.
2800 * 	Return
2801 * 		0
2802 *
2803 * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2804 * 	Description
2805 * 		Attempt to set the value of the **bpf_sock_ops_cb_flags** field
2806 * 		for the full TCP socket associated to *bpf_sock_ops* to
2807 * 		*argval*.
2808 *
2809 * 		The primary use of this field is to determine if there should
2810 * 		be calls to eBPF programs of type
2811 * 		**BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
2812 * 		code. A program of the same type can change its value, per
2813 * 		connection and as necessary, when the connection is
2814 * 		established. This field is directly accessible for reading, but
2815 * 		this helper must be used for updates in order to return an
2816 * 		error if an eBPF program tries to set a callback that is not
2817 * 		supported in the current kernel.
2818 *
2819 * 		*argval* is a flag array which can combine these flags:
2820 *
2821 * 		* **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
2822 * 		* **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
2823 * 		* **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
2824 * 		* **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
2825 *
2826 * 		Therefore, this function can be used to clear a callback flag by
2827 * 		setting the appropriate bit to zero. e.g. to disable the RTO
2828 * 		callback:
2829 *
2830 * 		**bpf_sock_ops_cb_flags_set(bpf_sock,**
2831 * 			**bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
2832 *
2833 * 		Here are some examples of where one could call such eBPF
2834 * 		program:
2835 *
2836 * 		* When RTO fires.
2837 * 		* When a packet is retransmitted.
2838 * 		* When the connection terminates.
2839 * 		* When a packet is sent.
2840 * 		* When a packet is received.
2841 * 	Return
2842 * 		Code **-EINVAL** if the socket is not a full TCP socket;
2843 * 		otherwise, a positive number containing the bits that could not
2844 * 		be set is returned (which comes down to 0 if all bits were set
2845 * 		as required).
2846 *
2847 * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
2848 * 	Description
2849 * 		This helper is used in programs implementing policies at the
2850 * 		socket level. If the message *msg* is allowed to pass (i.e. if
2851 * 		the verdict eBPF program returns **SK_PASS**), redirect it to
2852 * 		the socket referenced by *map* (of type
2853 * 		**BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2854 * 		egress interfaces can be used for redirection. The
2855 * 		**BPF_F_INGRESS** value in *flags* is used to make the
2856 * 		distinction (ingress path is selected if the flag is present,
2857 * 		egress path otherwise). This is the only flag supported for now.
2858 * 	Return
2859 * 		**SK_PASS** on success, or **SK_DROP** on error.
2860 *
2861 * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2862 * 	Description
2863 * 		For socket policies, apply the verdict of the eBPF program to
2864 * 		the next *bytes* (number of bytes) of message *msg*.
2865 *
2866 * 		For example, this helper can be used in the following cases:
2867 *
2868 * 		* A single **sendmsg**\ () or **sendfile**\ () system call
2869 * 		  contains multiple logical messages that the eBPF program is
2870 * 		  supposed to read and for which it should apply a verdict.
2871 * 		* An eBPF program only cares to read the first *bytes* of a
2872 * 		  *msg*. If the message has a large payload, then setting up
2873 * 		  and calling the eBPF program repeatedly for all bytes, even
2874 * 		  though the verdict is already known, would create unnecessary
2875 * 		  overhead.
2876 *
2877 * 		When called from within an eBPF program, the helper sets a
2878 * 		counter internal to the BPF infrastructure, that is used to
2879 * 		apply the last verdict to the next *bytes*. If *bytes* is
2880 * 		smaller than the current data being processed from a
2881 * 		**sendmsg**\ () or **sendfile**\ () system call, the first
2882 * 		*bytes* will be sent and the eBPF program will be re-run with
2883 * 		the pointer for start of data pointing to byte number *bytes*
2884 * 		**+ 1**. If *bytes* is larger than the current data being
2885 * 		processed, then the eBPF verdict will be applied to multiple
2886 * 		**sendmsg**\ () or **sendfile**\ () calls until *bytes* are
2887 * 		consumed.
2888 *
2889 * 		Note that if a socket closes with the internal counter holding
2890 * 		a non-zero value, this is not a problem because data is not
2891 * 		being buffered for *bytes* and is sent as it is received.
2892 * 	Return
2893 * 		0
2894 *
2895 * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2896 * 	Description
2897 * 		For socket policies, prevent the execution of the verdict eBPF
2898 * 		program for message *msg* until *bytes* (byte number) have been
2899 * 		accumulated.
2900 *
2901 * 		This can be used when one needs a specific number of bytes
2902 * 		before a verdict can be assigned, even if the data spans
2903 * 		multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
2904 * 		case would be a user calling **sendmsg**\ () repeatedly with
2905 * 		1-byte long message segments. Obviously, this is bad for
2906 * 		performance, but it is still valid. If the eBPF program needs
2907 * 		*bytes* bytes to validate a header, this helper can be used to
2908 * 		prevent the eBPF program to be called again until *bytes* have
2909 * 		been accumulated.
2910 * 	Return
2911 * 		0
2912 *
2913 * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2914 * 	Description
2915 * 		For socket policies, pull in non-linear data from user space
2916 * 		for *msg* and set pointers *msg*\ **->data** and *msg*\
2917 * 		**->data_end** to *start* and *end* bytes offsets into *msg*,
2918 * 		respectively.
2919 *
2920 * 		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2921 * 		*msg* it can only parse data that the (**data**, **data_end**)
2922 * 		pointers have already consumed. For **sendmsg**\ () hooks this
2923 * 		is likely the first scatterlist element. But for calls relying
2924 * 		on the **sendpage** handler (e.g. **sendfile**\ ()) this will
2925 * 		be the range (**0**, **0**) because the data is shared with
2926 * 		user space and by default the objective is to avoid allowing
2927 * 		user space to modify data while (or after) eBPF verdict is
2928 * 		being decided. This helper can be used to pull in data and to
2929 * 		set the start and end pointer to given values. Data will be
2930 * 		copied if necessary (i.e. if data was not linear and if start
2931 * 		and end pointers do not point to the same chunk).
2932 *
2933 * 		A call to this helper is susceptible to change the underlying
2934 * 		packet buffer. Therefore, at load time, all checks on pointers
2935 * 		previously done by the verifier are invalidated and must be
2936 * 		performed again, if the helper is used in combination with
2937 * 		direct packet access.
2938 *
2939 * 		All values for *flags* are reserved for future usage, and must
2940 * 		be left at zero.
2941 * 	Return
2942 * 		0 on success, or a negative error in case of failure.
2943 *
2944 * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
2945 * 	Description
2946 * 		Bind the socket associated to *ctx* to the address pointed by
2947 * 		*addr*, of length *addr_len*. This allows for making outgoing
2948 * 		connection from the desired IP address, which can be useful for
2949 * 		example when all processes inside a cgroup should use one
2950 * 		single IP address on a host that has multiple IP configured.
2951 *
2952 * 		This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2953 * 		domain (*addr*\ **->sa_family**) must be **AF_INET** (or
2954 * 		**AF_INET6**). It's advised to pass zero port (**sin_port**
2955 * 		or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
2956 * 		behavior and lets the kernel efficiently pick up an unused
2957 * 		port as long as 4-tuple is unique. Passing non-zero port might
2958 * 		lead to degraded performance.
2959 * 	Return
2960 * 		0 on success, or a negative error in case of failure.
2961 *
2962 * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2963 * 	Description
2964 * 		Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
2965 * 		possible to both shrink and grow the packet tail.
2966 * 		Shrink done via *delta* being a negative integer.
2967 *
2968 * 		A call to this helper is susceptible to change the underlying
2969 * 		packet buffer. Therefore, at load time, all checks on pointers
2970 * 		previously done by the verifier are invalidated and must be
2971 * 		performed again, if the helper is used in combination with
2972 * 		direct packet access.
2973 * 	Return
2974 * 		0 on success, or a negative error in case of failure.
2975 *
2976 * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
2977 * 	Description
2978 * 		Retrieve the XFRM state (IP transform framework, see also
2979 * 		**ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
2980 *
2981 * 		The retrieved value is stored in the **struct bpf_xfrm_state**
2982 * 		pointed by *xfrm_state* and of length *size*.
2983 *
2984 * 		All values for *flags* are reserved for future usage, and must
2985 * 		be left at zero.
2986 *
2987 * 		This helper is available only if the kernel was compiled with
2988 * 		**CONFIG_XFRM** configuration option.
2989 * 	Return
2990 * 		0 on success, or a negative error in case of failure.
2991 *
2992 * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
2993 * 	Description
2994 * 		Return a user or a kernel stack in bpf program provided buffer.
2995 * 		To achieve this, the helper needs *ctx*, which is a pointer
2996 * 		to the context on which the tracing program is executed.
2997 * 		To store the stacktrace, the bpf program provides *buf* with
2998 * 		a nonnegative *size*.
2999 *
3000 * 		The last argument, *flags*, holds the number of stack frames to
3001 * 		skip (from 0 to 255), masked with
3002 * 		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
3003 * 		the following flags:
3004 *
3005 * 		**BPF_F_USER_STACK**
3006 * 			Collect a user space stack instead of a kernel stack.
3007 * 		**BPF_F_USER_BUILD_ID**
3008 * 			Collect buildid+offset instead of ips for user stack,
3009 * 			only valid if **BPF_F_USER_STACK** is also specified.
3010 *
3011 * 		**bpf_get_stack**\ () can collect up to
3012 * 		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
3013 * 		to sufficient large buffer size. Note that
3014 * 		this limit can be controlled with the **sysctl** program, and
3015 * 		that it should be manually increased in order to profile long
3016 * 		user stacks (such as stacks for Java programs). To do so, use:
3017 *
3018 * 		::
3019 *
3020 * 			# sysctl kernel.perf_event_max_stack=<new value>
3021 * 	Return
3022 * 		The non-negative copied *buf* length equal to or less than
3023 * 		*size* on success, or a negative error in case of failure.
3024 *
3025 * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
3026 * 	Description
3027 * 		This helper is similar to **bpf_skb_load_bytes**\ () in that
3028 * 		it provides an easy way to load *len* bytes from *offset*
3029 * 		from the packet associated to *skb*, into the buffer pointed
3030 * 		by *to*. The difference to **bpf_skb_load_bytes**\ () is that
3031 * 		a fifth argument *start_header* exists in order to select a
3032 * 		base offset to start from. *start_header* can be one of:
3033 *
3034 * 		**BPF_HDR_START_MAC**
3035 * 			Base offset to load data from is *skb*'s mac header.
3036 * 		**BPF_HDR_START_NET**
3037 * 			Base offset to load data from is *skb*'s network header.
3038 *
3039 * 		In general, "direct packet access" is the preferred method to
3040 * 		access packet data, however, this helper is in particular useful
3041 * 		in socket filters where *skb*\ **->data** does not always point
3042 * 		to the start of the mac header and where "direct packet access"
3043 * 		is not available.
3044 * 	Return
3045 * 		0 on success, or a negative error in case of failure.
3046 *
3047 * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
3048 *	Description
3049 *		Do FIB lookup in kernel tables using parameters in *params*.
3050 *		If lookup is successful and result shows packet is to be
3051 *		forwarded, the neighbor tables are searched for the nexthop.
3052 *		If successful (ie., FIB lookup shows forwarding and nexthop
3053 *		is resolved), the nexthop address is returned in ipv4_dst
3054 *		or ipv6_dst based on family, smac is set to mac address of
3055 *		egress device, dmac is set to nexthop mac address, rt_metric
3056 *		is set to metric from route (IPv4/IPv6 only), and ifindex
3057 *		is set to the device index of the nexthop from the FIB lookup.
3058 *
3059 *		*plen* argument is the size of the passed in struct.
3060 *		*flags* argument can be a combination of one or more of the
3061 *		following values:
3062 *
3063 *		**BPF_FIB_LOOKUP_DIRECT**
3064 *			Do a direct table lookup vs full lookup using FIB
3065 *			rules.
3066 *		**BPF_FIB_LOOKUP_OUTPUT**
3067 *			Perform lookup from an egress perspective (default is
3068 *			ingress).
3069 *
3070 *		*ctx* is either **struct xdp_md** for XDP programs or
3071 *		**struct sk_buff** tc cls_act programs.
3072 *	Return
3073 *		* < 0 if any input argument is invalid
3074 *		*   0 on success (packet is forwarded, nexthop neighbor exists)
3075 *		* > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
3076 *		  packet is not forwarded or needs assist from full stack
3077 *
3078 *		If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3079 *		was exceeded and output params->mtu_result contains the MTU.
3080 *
3081 * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
3082 *	Description
3083 *		Add an entry to, or update a sockhash *map* referencing sockets.
3084 *		The *skops* is used as a new value for the entry associated to
3085 *		*key*. *flags* is one of:
3086 *
3087 *		**BPF_NOEXIST**
3088 *			The entry for *key* must not exist in the map.
3089 *		**BPF_EXIST**
3090 *			The entry for *key* must already exist in the map.
3091 *		**BPF_ANY**
3092 *			No condition on the existence of the entry for *key*.
3093 *
3094 *		If the *map* has eBPF programs (parser and verdict), those will
3095 *		be inherited by the socket being added. If the socket is
3096 *		already attached to eBPF programs, this results in an error.
3097 *	Return
3098 *		0 on success, or a negative error in case of failure.
3099 *
3100 * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
3101 *	Description
3102 *		This helper is used in programs implementing policies at the
3103 *		socket level. If the message *msg* is allowed to pass (i.e. if
3104 *		the verdict eBPF program returns **SK_PASS**), redirect it to
3105 *		the socket referenced by *map* (of type
3106 *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3107 *		egress interfaces can be used for redirection. The
3108 *		**BPF_F_INGRESS** value in *flags* is used to make the
3109 *		distinction (ingress path is selected if the flag is present,
3110 *		egress path otherwise). This is the only flag supported for now.
3111 *	Return
3112 *		**SK_PASS** on success, or **SK_DROP** on error.
3113 *
3114 * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
3115 *	Description
3116 *		This helper is used in programs implementing policies at the
3117 *		skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
3118 *		if the verdict eBPF program returns **SK_PASS**), redirect it
3119 *		to the socket referenced by *map* (of type
3120 *		**BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3121 *		egress interfaces can be used for redirection. The
3122 *		**BPF_F_INGRESS** value in *flags* is used to make the
3123 *		distinction (ingress path is selected if the flag is present,
3124 *		egress otherwise). This is the only flag supported for now.
3125 *	Return
3126 *		**SK_PASS** on success, or **SK_DROP** on error.
3127 *
3128 * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
3129 *	Description
3130 *		Encapsulate the packet associated to *skb* within a Layer 3
3131 *		protocol header. This header is provided in the buffer at
3132 *		address *hdr*, with *len* its size in bytes. *type* indicates
3133 *		the protocol of the header and can be one of:
3134 *
3135 *		**BPF_LWT_ENCAP_SEG6**
3136 *			IPv6 encapsulation with Segment Routing Header
3137 *			(**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
3138 *			the IPv6 header is computed by the kernel.
3139 *		**BPF_LWT_ENCAP_SEG6_INLINE**
3140 *			Only works if *skb* contains an IPv6 packet. Insert a
3141 *			Segment Routing Header (**struct ipv6_sr_hdr**) inside
3142 *			the IPv6 header.
3143 *		**BPF_LWT_ENCAP_IP**
3144 *			IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3145 *			must be IPv4 or IPv6, followed by zero or more
3146 *			additional headers, up to **LWT_BPF_MAX_HEADROOM**
3147 *			total bytes in all prepended headers. Please note that
3148 *			if **skb_is_gso**\ (*skb*) is true, no more than two
3149 *			headers can be prepended, and the inner header, if
3150 *			present, should be either GRE or UDP/GUE.
3151 *
3152 *		**BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
3153 *		of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
3154 *		be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
3155 *		**BPF_PROG_TYPE_LWT_XMIT**.
3156 *
3157 * 		A call to this helper is susceptible to change the underlying
3158 * 		packet buffer. Therefore, at load time, all checks on pointers
3159 * 		previously done by the verifier are invalidated and must be
3160 * 		performed again, if the helper is used in combination with
3161 * 		direct packet access.
3162 *	Return
3163 * 		0 on success, or a negative error in case of failure.
3164 *
3165 * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
3166 *	Description
3167 *		Store *len* bytes from address *from* into the packet
3168 *		associated to *skb*, at *offset*. Only the flags, tag and TLVs
3169 *		inside the outermost IPv6 Segment Routing Header can be
3170 *		modified through this helper.
3171 *
3172 * 		A call to this helper is susceptible to change the underlying
3173 * 		packet buffer. Therefore, at load time, all checks on pointers
3174 * 		previously done by the verifier are invalidated and must be
3175 * 		performed again, if the helper is used in combination with
3176 * 		direct packet access.
3177 *	Return
3178 * 		0 on success, or a negative error in case of failure.
3179 *
3180 * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3181 *	Description
3182 *		Adjust the size allocated to TLVs in the outermost IPv6
3183 *		Segment Routing Header contained in the packet associated to
3184 *		*skb*, at position *offset* by *delta* bytes. Only offsets
3185 *		after the segments are accepted. *delta* can be as well
3186 *		positive (growing) as negative (shrinking).
3187 *
3188 * 		A call to this helper is susceptible to change the underlying
3189 * 		packet buffer. Therefore, at load time, all checks on pointers
3190 * 		previously done by the verifier are invalidated and must be
3191 * 		performed again, if the helper is used in combination with
3192 * 		direct packet access.
3193 *	Return
3194 * 		0 on success, or a negative error in case of failure.
3195 *
3196 * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
3197 *	Description
3198 *		Apply an IPv6 Segment Routing action of type *action* to the
3199 *		packet associated to *skb*. Each action takes a parameter
3200 *		contained at address *param*, and of length *param_len* bytes.
3201 *		*action* can be one of:
3202 *
3203 *		**SEG6_LOCAL_ACTION_END_X**
3204 *			End.X action: Endpoint with Layer-3 cross-connect.
3205 *			Type of *param*: **struct in6_addr**.
3206 *		**SEG6_LOCAL_ACTION_END_T**
3207 *			End.T action: Endpoint with specific IPv6 table lookup.
3208 *			Type of *param*: **int**.
3209 *		**SEG6_LOCAL_ACTION_END_B6**
3210 *			End.B6 action: Endpoint bound to an SRv6 policy.
3211 *			Type of *param*: **struct ipv6_sr_hdr**.
3212 *		**SEG6_LOCAL_ACTION_END_B6_ENCAP**
3213 *			End.B6.Encap action: Endpoint bound to an SRv6
3214 *			encapsulation policy.
3215 *			Type of *param*: **struct ipv6_sr_hdr**.
3216 *
3217 * 		A call to this helper is susceptible to change the underlying
3218 * 		packet buffer. Therefore, at load time, all checks on pointers
3219 * 		previously done by the verifier are invalidated and must be
3220 * 		performed again, if the helper is used in combination with
3221 * 		direct packet access.
3222 *	Return
3223 * 		0 on success, or a negative error in case of failure.
3224 *
3225 * long bpf_rc_repeat(void *ctx)
3226 *	Description
3227 *		This helper is used in programs implementing IR decoding, to
3228 *		report a successfully decoded repeat key message. This delays
3229 *		the generation of a key up event for previously generated
3230 *		key down event.
3231 *
3232 *		Some IR protocols like NEC have a special IR message for
3233 *		repeating last button, for when a button is held down.
3234 *
3235 *		The *ctx* should point to the lirc sample as passed into
3236 *		the program.
3237 *
3238 *		This helper is only available is the kernel was compiled with
3239 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3240 *		"**y**".
3241 *	Return
3242 *		0
3243 *
3244 * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3245 *	Description
3246 *		This helper is used in programs implementing IR decoding, to
3247 *		report a successfully decoded key press with *scancode*,
3248 *		*toggle* value in the given *protocol*. The scancode will be
3249 *		translated to a keycode using the rc keymap, and reported as
3250 *		an input key down event. After a period a key up event is
3251 *		generated. This period can be extended by calling either
3252 *		**bpf_rc_keydown**\ () again with the same values, or calling
3253 *		**bpf_rc_repeat**\ ().
3254 *
3255 *		Some protocols include a toggle bit, in case the button was
3256 *		released and pressed again between consecutive scancodes.
3257 *
3258 *		The *ctx* should point to the lirc sample as passed into
3259 *		the program.
3260 *
3261 *		The *protocol* is the decoded protocol number (see
3262 *		**enum rc_proto** for some predefined values).
3263 *
3264 *		This helper is only available is the kernel was compiled with
3265 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3266 *		"**y**".
3267 *	Return
3268 *		0
3269 *
3270 * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3271 * 	Description
3272 * 		Return the cgroup v2 id of the socket associated with the *skb*.
3273 * 		This is roughly similar to the **bpf_get_cgroup_classid**\ ()
3274 * 		helper for cgroup v1 by providing a tag resp. identifier that
3275 * 		can be matched on or used for map lookups e.g. to implement
3276 * 		policy. The cgroup v2 id of a given path in the hierarchy is
3277 * 		exposed in user space through the f_handle API in order to get
3278 * 		to the same 64-bit id.
3279 *
3280 * 		This helper can be used on TC egress path, but not on ingress,
3281 * 		and is available only if the kernel was compiled with the
3282 * 		**CONFIG_SOCK_CGROUP_DATA** configuration option.
3283 * 	Return
3284 * 		The id is returned or 0 in case the id could not be retrieved.
3285 *
3286 * u64 bpf_get_current_cgroup_id(void)
3287 * 	Description
3288 * 		Get the current cgroup id based on the cgroup within which
3289 * 		the current task is running.
3290 * 	Return
3291 * 		A 64-bit integer containing the current cgroup id based
3292 * 		on the cgroup within which the current task is running.
3293 *
3294 * void *bpf_get_local_storage(void *map, u64 flags)
3295 *	Description
3296 *		Get the pointer to the local storage area.
3297 *		The type and the size of the local storage is defined
3298 *		by the *map* argument.
3299 *		The *flags* meaning is specific for each map type,
3300 *		and has to be 0 for cgroup local storage.
3301 *
3302 *		Depending on the BPF program type, a local storage area
3303 *		can be shared between multiple instances of the BPF program,
3304 *		running simultaneously.
3305 *
3306 *		A user should care about the synchronization by himself.
3307 *		For example, by using the **BPF_ATOMIC** instructions to alter
3308 *		the shared data.
3309 *	Return
3310 *		A pointer to the local storage area.
3311 *
3312 * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
3313 *	Description
3314 *		Select a **SO_REUSEPORT** socket from a
3315 *		**BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
3316 *		It checks the selected socket is matching the incoming
3317 *		request in the socket buffer.
3318 *	Return
3319 *		0 on success, or a negative error in case of failure.
3320 *
3321 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3322 *	Description
3323 *		Return id of cgroup v2 that is ancestor of cgroup associated
3324 *		with the *skb* at the *ancestor_level*.  The root cgroup is at
3325 *		*ancestor_level* zero and each step down the hierarchy
3326 *		increments the level. If *ancestor_level* == level of cgroup
3327 *		associated with *skb*, then return value will be same as that
3328 *		of **bpf_skb_cgroup_id**\ ().
3329 *
3330 *		The helper is useful to implement policies based on cgroups
3331 *		that are upper in hierarchy than immediate cgroup associated
3332 *		with *skb*.
3333 *
3334 *		The format of returned id and helper limitations are same as in
3335 *		**bpf_skb_cgroup_id**\ ().
3336 *	Return
3337 *		The id is returned or 0 in case the id could not be retrieved.
3338 *
3339 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3340 *	Description
3341 *		Look for TCP socket matching *tuple*, optionally in a child
3342 *		network namespace *netns*. The return value must be checked,
3343 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3344 *
3345 *		The *ctx* should point to the context of the program, such as
3346 *		the skb or socket (depending on the hook in use). This is used
3347 *		to determine the base network namespace for the lookup.
3348 *
3349 *		*tuple_size* must be one of:
3350 *
3351 *		**sizeof**\ (*tuple*\ **->ipv4**)
3352 *			Look for an IPv4 socket.
3353 *		**sizeof**\ (*tuple*\ **->ipv6**)
3354 *			Look for an IPv6 socket.
3355 *
3356 *		If the *netns* is a negative signed 32-bit integer, then the
3357 *		socket lookup table in the netns associated with the *ctx*
3358 *		will be used. For the TC hooks, this is the netns of the device
3359 *		in the skb. For socket hooks, this is the netns of the socket.
3360 *		If *netns* is any other signed 32-bit value greater than or
3361 *		equal to zero then it specifies the ID of the netns relative to
3362 *		the netns associated with the *ctx*. *netns* values beyond the
3363 *		range of 32-bit integers are reserved for future use.
3364 *
3365 *		All values for *flags* are reserved for future usage, and must
3366 *		be left at zero.
3367 *
3368 *		This helper is available only if the kernel was compiled with
3369 *		**CONFIG_NET** configuration option.
3370 *	Return
3371 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3372 *		For sockets with reuseport option, the **struct bpf_sock**
3373 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3374 *		tuple.
3375 *
3376 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3377 *	Description
3378 *		Look for UDP socket matching *tuple*, optionally in a child
3379 *		network namespace *netns*. The return value must be checked,
3380 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3381 *
3382 *		The *ctx* should point to the context of the program, such as
3383 *		the skb or socket (depending on the hook in use). This is used
3384 *		to determine the base network namespace for the lookup.
3385 *
3386 *		*tuple_size* must be one of:
3387 *
3388 *		**sizeof**\ (*tuple*\ **->ipv4**)
3389 *			Look for an IPv4 socket.
3390 *		**sizeof**\ (*tuple*\ **->ipv6**)
3391 *			Look for an IPv6 socket.
3392 *
3393 *		If the *netns* is a negative signed 32-bit integer, then the
3394 *		socket lookup table in the netns associated with the *ctx*
3395 *		will be used. For the TC hooks, this is the netns of the device
3396 *		in the skb. For socket hooks, this is the netns of the socket.
3397 *		If *netns* is any other signed 32-bit value greater than or
3398 *		equal to zero then it specifies the ID of the netns relative to
3399 *		the netns associated with the *ctx*. *netns* values beyond the
3400 *		range of 32-bit integers are reserved for future use.
3401 *
3402 *		All values for *flags* are reserved for future usage, and must
3403 *		be left at zero.
3404 *
3405 *		This helper is available only if the kernel was compiled with
3406 *		**CONFIG_NET** configuration option.
3407 *	Return
3408 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3409 *		For sockets with reuseport option, the **struct bpf_sock**
3410 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3411 *		tuple.
3412 *
3413 * long bpf_sk_release(void *sock)
3414 *	Description
3415 *		Release the reference held by *sock*. *sock* must be a
3416 *		non-**NULL** pointer that was returned from
3417 *		**bpf_sk_lookup_xxx**\ ().
3418 *	Return
3419 *		0 on success, or a negative error in case of failure.
3420 *
3421 * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
3422 * 	Description
3423 * 		Push an element *value* in *map*. *flags* is one of:
3424 *
3425 * 		**BPF_EXIST**
3426 * 			If the queue/stack is full, the oldest element is
3427 * 			removed to make room for this.
3428 * 	Return
3429 * 		0 on success, or a negative error in case of failure.
3430 *
3431 * long bpf_map_pop_elem(struct bpf_map *map, void *value)
3432 * 	Description
3433 * 		Pop an element from *map*.
3434 * 	Return
3435 * 		0 on success, or a negative error in case of failure.
3436 *
3437 * long bpf_map_peek_elem(struct bpf_map *map, void *value)
3438 * 	Description
3439 * 		Get an element from *map* without removing it.
3440 * 	Return
3441 * 		0 on success, or a negative error in case of failure.
3442 *
3443 * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3444 *	Description
3445 *		For socket policies, insert *len* bytes into *msg* at offset
3446 *		*start*.
3447 *
3448 *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
3449 *		*msg* it may want to insert metadata or options into the *msg*.
3450 *		This can later be read and used by any of the lower layer BPF
3451 *		hooks.
3452 *
3453 *		This helper may fail if under memory pressure (a malloc
3454 *		fails) in these cases BPF programs will get an appropriate
3455 *		error and BPF programs will need to handle them.
3456 *	Return
3457 *		0 on success, or a negative error in case of failure.
3458 *
3459 * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3460 *	Description
3461 *		Will remove *len* bytes from a *msg* starting at byte *start*.
3462 *		This may result in **ENOMEM** errors under certain situations if
3463 *		an allocation and copy are required due to a full ring buffer.
3464 *		However, the helper will try to avoid doing the allocation
3465 *		if possible. Other errors can occur if input parameters are
3466 *		invalid either due to *start* byte not being valid part of *msg*
3467 *		payload and/or *pop* value being to large.
3468 *	Return
3469 *		0 on success, or a negative error in case of failure.
3470 *
3471 * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3472 *	Description
3473 *		This helper is used in programs implementing IR decoding, to
3474 *		report a successfully decoded pointer movement.
3475 *
3476 *		The *ctx* should point to the lirc sample as passed into
3477 *		the program.
3478 *
3479 *		This helper is only available is the kernel was compiled with
3480 *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3481 *		"**y**".
3482 *	Return
3483 *		0
3484 *
3485 * long bpf_spin_lock(struct bpf_spin_lock *lock)
3486 *	Description
3487 *		Acquire a spinlock represented by the pointer *lock*, which is
3488 *		stored as part of a value of a map. Taking the lock allows to
3489 *		safely update the rest of the fields in that value. The
3490 *		spinlock can (and must) later be released with a call to
3491 *		**bpf_spin_unlock**\ (\ *lock*\ ).
3492 *
3493 *		Spinlocks in BPF programs come with a number of restrictions
3494 *		and constraints:
3495 *
3496 *		* **bpf_spin_lock** objects are only allowed inside maps of
3497 *		  types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
3498 *		  list could be extended in the future).
3499 *		* BTF description of the map is mandatory.
3500 *		* The BPF program can take ONE lock at a time, since taking two
3501 *		  or more could cause dead locks.
3502 *		* Only one **struct bpf_spin_lock** is allowed per map element.
3503 *		* When the lock is taken, calls (either BPF to BPF or helpers)
3504 *		  are not allowed.
3505 *		* The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
3506 *		  allowed inside a spinlock-ed region.
3507 *		* The BPF program MUST call **bpf_spin_unlock**\ () to release
3508 *		  the lock, on all execution paths, before it returns.
3509 *		* The BPF program can access **struct bpf_spin_lock** only via
3510 *		  the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
3511 *		  helpers. Loading or storing data into the **struct
3512 *		  bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
3513 *		* To use the **bpf_spin_lock**\ () helper, the BTF description
3514 *		  of the map value must be a struct and have **struct
3515 *		  bpf_spin_lock** *anyname*\ **;** field at the top level.
3516 *		  Nested lock inside another struct is not allowed.
3517 *		* The **struct bpf_spin_lock** *lock* field in a map value must
3518 *		  be aligned on a multiple of 4 bytes in that value.
3519 *		* Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
3520 *		  the **bpf_spin_lock** field to user space.
3521 *		* Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
3522 *		  a BPF program, do not update the **bpf_spin_lock** field.
3523 *		* **bpf_spin_lock** cannot be on the stack or inside a
3524 *		  networking packet (it can only be inside of a map values).
3525 *		* **bpf_spin_lock** is available to root only.
3526 *		* Tracing programs and socket filter programs cannot use
3527 *		  **bpf_spin_lock**\ () due to insufficient preemption checks
3528 *		  (but this may change in the future).
3529 *		* **bpf_spin_lock** is not allowed in inner maps of map-in-map.
3530 *	Return
3531 *		0
3532 *
3533 * long bpf_spin_unlock(struct bpf_spin_lock *lock)
3534 *	Description
3535 *		Release the *lock* previously locked by a call to
3536 *		**bpf_spin_lock**\ (\ *lock*\ ).
3537 *	Return
3538 *		0
3539 *
3540 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
3541 *	Description
3542 *		This helper gets a **struct bpf_sock** pointer such
3543 *		that all the fields in this **bpf_sock** can be accessed.
3544 *	Return
3545 *		A **struct bpf_sock** pointer on success, or **NULL** in
3546 *		case of failure.
3547 *
3548 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
3549 *	Description
3550 *		This helper gets a **struct bpf_tcp_sock** pointer from a
3551 *		**struct bpf_sock** pointer.
3552 *	Return
3553 *		A **struct bpf_tcp_sock** pointer on success, or **NULL** in
3554 *		case of failure.
3555 *
3556 * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3557 *	Description
3558 *		Set ECN (Explicit Congestion Notification) field of IP header
3559 *		to **CE** (Congestion Encountered) if current value is **ECT**
3560 *		(ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3561 *		and IPv4.
3562 *	Return
3563 *		1 if the **CE** flag is set (either by the current helper call
3564 *		or because it was already present), 0 if it is not set.
3565 *
3566 * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
3567 *	Description
3568 *		Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
3569 *		**bpf_sk_release**\ () is unnecessary and not allowed.
3570 *	Return
3571 *		A **struct bpf_sock** pointer on success, or **NULL** in
3572 *		case of failure.
3573 *
3574 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3575 *	Description
3576 *		Look for TCP socket matching *tuple*, optionally in a child
3577 *		network namespace *netns*. The return value must be checked,
3578 *		and if non-**NULL**, released via **bpf_sk_release**\ ().
3579 *
3580 *		This function is identical to **bpf_sk_lookup_tcp**\ (), except
3581 *		that it also returns timewait or request sockets. Use
3582 *		**bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
3583 *		full structure.
3584 *
3585 *		This helper is available only if the kernel was compiled with
3586 *		**CONFIG_NET** configuration option.
3587 *	Return
3588 *		Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3589 *		For sockets with reuseport option, the **struct bpf_sock**
3590 *		result is from *reuse*\ **->socks**\ [] using the hash of the
3591 *		tuple.
3592 *
3593 * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3594 * 	Description
3595 * 		Check whether *iph* and *th* contain a valid SYN cookie ACK for
3596 * 		the listening socket in *sk*.
3597 *
3598 * 		*iph* points to the start of the IPv4 or IPv6 header, while
3599 * 		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3600 * 		**sizeof**\ (**struct ip6hdr**).
3601 *
3602 * 		*th* points to the start of the TCP header, while *th_len*
3603 * 		contains **sizeof**\ (**struct tcphdr**).
3604 * 	Return
3605 * 		0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
3606 * 		error otherwise.
3607 *
3608 * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
3609 *	Description
3610 *		Get name of sysctl in /proc/sys/ and copy it into provided by
3611 *		program buffer *buf* of size *buf_len*.
3612 *
3613 *		The buffer is always NUL terminated, unless it's zero-sized.
3614 *
3615 *		If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
3616 *		copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
3617 *		only (e.g. "tcp_mem").
3618 *	Return
3619 *		Number of character copied (not including the trailing NUL).
3620 *
3621 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3622 *		truncated name in this case).
3623 *
3624 * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3625 *	Description
3626 *		Get current value of sysctl as it is presented in /proc/sys
3627 *		(incl. newline, etc), and copy it as a string into provided
3628 *		by program buffer *buf* of size *buf_len*.
3629 *
3630 *		The whole value is copied, no matter what file position user
3631 *		space issued e.g. sys_read at.
3632 *
3633 *		The buffer is always NUL terminated, unless it's zero-sized.
3634 *	Return
3635 *		Number of character copied (not including the trailing NUL).
3636 *
3637 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3638 *		truncated name in this case).
3639 *
3640 *		**-EINVAL** if current value was unavailable, e.g. because
3641 *		sysctl is uninitialized and read returns -EIO for it.
3642 *
3643 * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3644 *	Description
3645 *		Get new value being written by user space to sysctl (before
3646 *		the actual write happens) and copy it as a string into
3647 *		provided by program buffer *buf* of size *buf_len*.
3648 *
3649 *		User space may write new value at file position > 0.
3650 *
3651 *		The buffer is always NUL terminated, unless it's zero-sized.
3652 *	Return
3653 *		Number of character copied (not including the trailing NUL).
3654 *
3655 *		**-E2BIG** if the buffer wasn't big enough (*buf* will contain
3656 *		truncated name in this case).
3657 *
3658 *		**-EINVAL** if sysctl is being read.
3659 *
3660 * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
3661 *	Description
3662 *		Override new value being written by user space to sysctl with
3663 *		value provided by program in buffer *buf* of size *buf_len*.
3664 *
3665 *		*buf* should contain a string in same form as provided by user
3666 *		space on sysctl write.
3667 *
3668 *		User space may write new value at file position > 0. To override
3669 *		the whole sysctl value file position should be set to zero.
3670 *	Return
3671 *		0 on success.
3672 *
3673 *		**-E2BIG** if the *buf_len* is too big.
3674 *
3675 *		**-EINVAL** if sysctl is being read.
3676 *
3677 * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
3678 *	Description
3679 *		Convert the initial part of the string from buffer *buf* of
3680 *		size *buf_len* to a long integer according to the given base
3681 *		and save the result in *res*.
3682 *
3683 *		The string may begin with an arbitrary amount of white space
3684 *		(as determined by **isspace**\ (3)) followed by a single
3685 *		optional '**-**' sign.
3686 *
3687 *		Five least significant bits of *flags* encode base, other bits
3688 *		are currently unused.
3689 *
3690 *		Base must be either 8, 10, 16 or 0 to detect it automatically
3691 *		similar to user space **strtol**\ (3).
3692 *	Return
3693 *		Number of characters consumed on success. Must be positive but
3694 *		no more than *buf_len*.
3695 *
3696 *		**-EINVAL** if no valid digits were found or unsupported base
3697 *		was provided.
3698 *
3699 *		**-ERANGE** if resulting value was out of range.
3700 *
3701 * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
3702 *	Description
3703 *		Convert the initial part of the string from buffer *buf* of
3704 *		size *buf_len* to an unsigned long integer according to the
3705 *		given base and save the result in *res*.
3706 *
3707 *		The string may begin with an arbitrary amount of white space
3708 *		(as determined by **isspace**\ (3)).
3709 *
3710 *		Five least significant bits of *flags* encode base, other bits
3711 *		are currently unused.
3712 *
3713 *		Base must be either 8, 10, 16 or 0 to detect it automatically
3714 *		similar to user space **strtoul**\ (3).
3715 *	Return
3716 *		Number of characters consumed on success. Must be positive but
3717 *		no more than *buf_len*.
3718 *
3719 *		**-EINVAL** if no valid digits were found or unsupported base
3720 *		was provided.
3721 *
3722 *		**-ERANGE** if resulting value was out of range.
3723 *
3724 * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
3725 *	Description
3726 *		Get a bpf-local-storage from a *sk*.
3727 *
3728 *		Logically, it could be thought of getting the value from
3729 *		a *map* with *sk* as the **key**.  From this
3730 *		perspective,  the usage is not much different from
3731 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
3732 *		helper enforces the key must be a full socket and the map must
3733 *		be a **BPF_MAP_TYPE_SK_STORAGE** also.
3734 *
3735 *		Underneath, the value is stored locally at *sk* instead of
3736 *		the *map*.  The *map* is used as the bpf-local-storage
3737 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
3738 *		searched against all bpf-local-storages residing at *sk*.
3739 *
3740 *		*sk* is a kernel **struct sock** pointer for LSM program.
3741 *		*sk* is a **struct bpf_sock** pointer for other program types.
3742 *
3743 *		An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
3744 *		used such that a new bpf-local-storage will be
3745 *		created if one does not exist.  *value* can be used
3746 *		together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
3747 *		the initial value of a bpf-local-storage.  If *value* is
3748 *		**NULL**, the new bpf-local-storage will be zero initialized.
3749 *	Return
3750 *		A bpf-local-storage pointer is returned on success.
3751 *
3752 *		**NULL** if not found or there was an error in adding
3753 *		a new bpf-local-storage.
3754 *
3755 * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
3756 *	Description
3757 *		Delete a bpf-local-storage from a *sk*.
3758 *	Return
3759 *		0 on success.
3760 *
3761 *		**-ENOENT** if the bpf-local-storage cannot be found.
3762 *		**-EINVAL** if sk is not a fullsock (e.g. a request_sock).
3763 *
3764 * long bpf_send_signal(u32 sig)
3765 *	Description
3766 *		Send signal *sig* to the process of the current task.
3767 *		The signal may be delivered to any of this process's threads.
3768 *	Return
3769 *		0 on success or successfully queued.
3770 *
3771 *		**-EBUSY** if work queue under nmi is full.
3772 *
3773 *		**-EINVAL** if *sig* is invalid.
3774 *
3775 *		**-EPERM** if no permission to send the *sig*.
3776 *
3777 *		**-EAGAIN** if bpf program can try again.
3778 *
3779 * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3780 *	Description
3781 *		Try to issue a SYN cookie for the packet with corresponding
3782 *		IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
3783 *
3784 *		*iph* points to the start of the IPv4 or IPv6 header, while
3785 *		*iph_len* contains **sizeof**\ (**struct iphdr**) or
3786 *		**sizeof**\ (**struct ip6hdr**).
3787 *
3788 *		*th* points to the start of the TCP header, while *th_len*
3789 *		contains the length of the TCP header.
3790 *	Return
3791 *		On success, lower 32 bits hold the generated SYN cookie in
3792 *		followed by 16 bits which hold the MSS value for that cookie,
3793 *		and the top 16 bits are unused.
3794 *
3795 *		On failure, the returned value is one of the following:
3796 *
3797 *		**-EINVAL** SYN cookie cannot be issued due to error
3798 *
3799 *		**-ENOENT** SYN cookie should not be issued (no SYN flood)
3800 *
3801 *		**-EOPNOTSUPP** kernel configuration does not enable SYN cookies
3802 *
3803 *		**-EPROTONOSUPPORT** IP packet version is not 4 or 6
3804 *
3805 * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3806 * 	Description
3807 * 		Write raw *data* blob into a special BPF perf event held by
3808 * 		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3809 * 		event must have the following attributes: **PERF_SAMPLE_RAW**
3810 * 		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3811 * 		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3812 *
3813 * 		The *flags* are used to indicate the index in *map* for which
3814 * 		the value must be put, masked with **BPF_F_INDEX_MASK**.
3815 * 		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3816 * 		to indicate that the index of the current CPU core should be
3817 * 		used.
3818 *
3819 * 		The value to write, of *size*, is passed through eBPF stack and
3820 * 		pointed by *data*.
3821 *
3822 * 		*ctx* is a pointer to in-kernel struct sk_buff.
3823 *
3824 * 		This helper is similar to **bpf_perf_event_output**\ () but
3825 * 		restricted to raw_tracepoint bpf programs.
3826 * 	Return
3827 * 		0 on success, or a negative error in case of failure.
3828 *
3829 * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
3830 * 	Description
3831 * 		Safely attempt to read *size* bytes from user space address
3832 * 		*unsafe_ptr* and store the data in *dst*.
3833 * 	Return
3834 * 		0 on success, or a negative error in case of failure.
3835 *
3836 * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
3837 * 	Description
3838 * 		Safely attempt to read *size* bytes from kernel space address
3839 * 		*unsafe_ptr* and store the data in *dst*.
3840 * 	Return
3841 * 		0 on success, or a negative error in case of failure.
3842 *
3843 * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
3844 * 	Description
3845 * 		Copy a NUL terminated string from an unsafe user address
3846 * 		*unsafe_ptr* to *dst*. The *size* should include the
3847 * 		terminating NUL byte. In case the string length is smaller than
3848 * 		*size*, the target is not padded with further NUL bytes. If the
3849 * 		string length is larger than *size*, just *size*-1 bytes are
3850 * 		copied and the last byte is set to NUL.
3851 *
3852 * 		On success, returns the number of bytes that were written,
3853 * 		including the terminal NUL. This makes this helper useful in
3854 * 		tracing programs for reading strings, and more importantly to
3855 * 		get its length at runtime. See the following snippet:
3856 *
3857 * 		::
3858 *
3859 * 			SEC("kprobe/sys_open")
3860 * 			void bpf_sys_open(struct pt_regs *ctx)
3861 * 			{
3862 * 			        char buf[PATHLEN]; // PATHLEN is defined to 256
3863 * 			        int res = bpf_probe_read_user_str(buf, sizeof(buf),
3864 * 				                                  ctx->di);
3865 *
3866 * 				// Consume buf, for example push it to
3867 * 				// userspace via bpf_perf_event_output(); we
3868 * 				// can use res (the string length) as event
3869 * 				// size, after checking its boundaries.
3870 * 			}
3871 *
3872 * 		In comparison, using **bpf_probe_read_user**\ () helper here
3873 * 		instead to read the string would require to estimate the length
3874 * 		at compile time, and would often result in copying more memory
3875 * 		than necessary.
3876 *
3877 * 		Another useful use case is when parsing individual process
3878 * 		arguments or individual environment variables navigating
3879 * 		*current*\ **->mm->arg_start** and *current*\
3880 * 		**->mm->env_start**: using this helper and the return value,
3881 * 		one can quickly iterate at the right offset of the memory area.
3882 * 	Return
3883 * 		On success, the strictly positive length of the output string,
3884 * 		including the trailing NUL character. On error, a negative
3885 * 		value.
3886 *
3887 * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
3888 * 	Description
3889 * 		Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
3890 * 		to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
3891 * 	Return
3892 * 		On success, the strictly positive length of the string, including
3893 * 		the trailing NUL character. On error, a negative value.
3894 *
3895 * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3896 *	Description
3897 *		Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
3898 *		*rcv_nxt* is the ack_seq to be sent out.
3899 *	Return
3900 *		0 on success, or a negative error in case of failure.
3901 *
3902 * long bpf_send_signal_thread(u32 sig)
3903 *	Description
3904 *		Send signal *sig* to the thread corresponding to the current task.
3905 *	Return
3906 *		0 on success or successfully queued.
3907 *
3908 *		**-EBUSY** if work queue under nmi is full.
3909 *
3910 *		**-EINVAL** if *sig* is invalid.
3911 *
3912 *		**-EPERM** if no permission to send the *sig*.
3913 *
3914 *		**-EAGAIN** if bpf program can try again.
3915 *
3916 * u64 bpf_jiffies64(void)
3917 *	Description
3918 *		Obtain the 64bit jiffies
3919 *	Return
3920 *		The 64 bit jiffies
3921 *
3922 * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
3923 *	Description
3924 *		For an eBPF program attached to a perf event, retrieve the
3925 *		branch records (**struct perf_branch_entry**) associated to *ctx*
3926 *		and store it in the buffer pointed by *buf* up to size
3927 *		*size* bytes.
3928 *	Return
3929 *		On success, number of bytes written to *buf*. On error, a
3930 *		negative value.
3931 *
3932 *		The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
3933 *		instead return the number of bytes required to store all the
3934 *		branch entries. If this flag is set, *buf* may be NULL.
3935 *
3936 *		**-EINVAL** if arguments invalid or **size** not a multiple
3937 *		of **sizeof**\ (**struct perf_branch_entry**\ ).
3938 *
3939 *		**-ENOENT** if architecture does not support branch records.
3940 *
3941 * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3942 *	Description
3943 *		Returns 0 on success, values for *pid* and *tgid* as seen from the current
3944 *		*namespace* will be returned in *nsdata*.
3945 *	Return
3946 *		0 on success, or one of the following in case of failure:
3947 *
3948 *		**-EINVAL** if dev and inum supplied don't match dev_t and inode number
3949 *              with nsfs of current task, or if dev conversion to dev_t lost high bits.
3950 *
3951 *		**-ENOENT** if pidns does not exists for the current task.
3952 *
3953 * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3954 *	Description
3955 *		Write raw *data* blob into a special BPF perf event held by
3956 *		*map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3957 *		event must have the following attributes: **PERF_SAMPLE_RAW**
3958 *		as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3959 *		**PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3960 *
3961 *		The *flags* are used to indicate the index in *map* for which
3962 *		the value must be put, masked with **BPF_F_INDEX_MASK**.
3963 *		Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3964 *		to indicate that the index of the current CPU core should be
3965 *		used.
3966 *
3967 *		The value to write, of *size*, is passed through eBPF stack and
3968 *		pointed by *data*.
3969 *
3970 *		*ctx* is a pointer to in-kernel struct xdp_buff.
3971 *
3972 *		This helper is similar to **bpf_perf_eventoutput**\ () but
3973 *		restricted to raw_tracepoint bpf programs.
3974 *	Return
3975 *		0 on success, or a negative error in case of failure.
3976 *
3977 * u64 bpf_get_netns_cookie(void *ctx)
3978 * 	Description
3979 * 		Retrieve the cookie (generated by the kernel) of the network
3980 * 		namespace the input *ctx* is associated with. The network
3981 * 		namespace cookie remains stable for its lifetime and provides
3982 * 		a global identifier that can be assumed unique. If *ctx* is
3983 * 		NULL, then the helper returns the cookie for the initial
3984 * 		network namespace. The cookie itself is very similar to that
3985 * 		of **bpf_get_socket_cookie**\ () helper, but for network
3986 * 		namespaces instead of sockets.
3987 * 	Return
3988 * 		A 8-byte long opaque number.
3989 *
3990 * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
3991 * 	Description
3992 * 		Return id of cgroup v2 that is ancestor of the cgroup associated
3993 * 		with the current task at the *ancestor_level*. The root cgroup
3994 * 		is at *ancestor_level* zero and each step down the hierarchy
3995 * 		increments the level. If *ancestor_level* == level of cgroup
3996 * 		associated with the current task, then return value will be the
3997 * 		same as that of **bpf_get_current_cgroup_id**\ ().
3998 *
3999 * 		The helper is useful to implement policies based on cgroups
4000 * 		that are upper in hierarchy than immediate cgroup associated
4001 * 		with the current task.
4002 *
4003 * 		The format of returned id and helper limitations are same as in
4004 * 		**bpf_get_current_cgroup_id**\ ().
4005 * 	Return
4006 * 		The id is returned or 0 in case the id could not be retrieved.
4007 *
4008 * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
4009 *	Description
4010 *		Helper is overloaded depending on BPF program type. This
4011 *		description applies to **BPF_PROG_TYPE_SCHED_CLS** and
4012 *		**BPF_PROG_TYPE_SCHED_ACT** programs.
4013 *
4014 *		Assign the *sk* to the *skb*. When combined with appropriate
4015 *		routing configuration to receive the packet towards the socket,
4016 *		will cause *skb* to be delivered to the specified socket.
4017 *		Subsequent redirection of *skb* via  **bpf_redirect**\ (),
4018 *		**bpf_clone_redirect**\ () or other methods outside of BPF may
4019 *		interfere with successful delivery to the socket.
4020 *
4021 *		This operation is only valid from TC ingress path.
4022 *
4023 *		The *flags* argument must be zero.
4024 *	Return
4025 *		0 on success, or a negative error in case of failure:
4026 *
4027 *		**-EINVAL** if specified *flags* are not supported.
4028 *
4029 *		**-ENOENT** if the socket is unavailable for assignment.
4030 *
4031 *		**-ENETUNREACH** if the socket is unreachable (wrong netns).
4032 *
4033 *		**-EOPNOTSUPP** if the operation is not supported, for example
4034 *		a call from outside of TC ingress.
4035 *
4036 *		**-ESOCKTNOSUPPORT** if the socket type is not supported
4037 *		(reuseport).
4038 *
4039 * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
4040 *	Description
4041 *		Helper is overloaded depending on BPF program type. This
4042 *		description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
4043 *
4044 *		Select the *sk* as a result of a socket lookup.
4045 *
4046 *		For the operation to succeed passed socket must be compatible
4047 *		with the packet description provided by the *ctx* object.
4048 *
4049 *		L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
4050 *		be an exact match. While IP family (**AF_INET** or
4051 *		**AF_INET6**) must be compatible, that is IPv6 sockets
4052 *		that are not v6-only can be selected for IPv4 packets.
4053 *
4054 *		Only TCP listeners and UDP unconnected sockets can be
4055 *		selected. *sk* can also be NULL to reset any previous
4056 *		selection.
4057 *
4058 *		*flags* argument can combination of following values:
4059 *
4060 *		* **BPF_SK_LOOKUP_F_REPLACE** to override the previous
4061 *		  socket selection, potentially done by a BPF program
4062 *		  that ran before us.
4063 *
4064 *		* **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
4065 *		  load-balancing within reuseport group for the socket
4066 *		  being selected.
4067 *
4068 *		On success *ctx->sk* will point to the selected socket.
4069 *
4070 *	Return
4071 *		0 on success, or a negative errno in case of failure.
4072 *
4073 *		* **-EAFNOSUPPORT** if socket family (*sk->family*) is
4074 *		  not compatible with packet family (*ctx->family*).
4075 *
4076 *		* **-EEXIST** if socket has been already selected,
4077 *		  potentially by another program, and
4078 *		  **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
4079 *
4080 *		* **-EINVAL** if unsupported flags were specified.
4081 *
4082 *		* **-EPROTOTYPE** if socket L4 protocol
4083 *		  (*sk->protocol*) doesn't match packet protocol
4084 *		  (*ctx->protocol*).
4085 *
4086 *		* **-ESOCKTNOSUPPORT** if socket is not in allowed
4087 *		  state (TCP listening or UDP unconnected).
4088 *
4089 * u64 bpf_ktime_get_boot_ns(void)
4090 * 	Description
4091 * 		Return the time elapsed since system boot, in nanoseconds.
4092 * 		Does include the time the system was suspended.
4093 * 		See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
4094 * 	Return
4095 * 		Current *ktime*.
4096 *
4097 * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4098 * 	Description
4099 * 		**bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
4100 * 		out the format string.
4101 * 		The *m* represents the seq_file. The *fmt* and *fmt_size* are for
4102 * 		the format string itself. The *data* and *data_len* are format string
4103 * 		arguments. The *data* are a **u64** array and corresponding format string
4104 * 		values are stored in the array. For strings and pointers where pointees
4105 * 		are accessed, only the pointer values are stored in the *data* array.
4106 * 		The *data_len* is the size of *data* in bytes - must be a multiple of 8.
4107 *
4108 *		Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
4109 *		Reading kernel memory may fail due to either invalid address or
4110 *		valid address but requiring a major memory fault. If reading kernel memory
4111 *		fails, the string for **%s** will be an empty string, and the ip
4112 *		address for **%p{i,I}{4,6}** will be 0. Not returning error to
4113 *		bpf program is consistent with what **bpf_trace_printk**\ () does for now.
4114 * 	Return
4115 * 		0 on success, or a negative error in case of failure:
4116 *
4117 *		**-EBUSY** if per-CPU memory copy buffer is busy, can try again
4118 *		by returning 1 from bpf program.
4119 *
4120 *		**-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
4121 *
4122 *		**-E2BIG** if *fmt* contains too many format specifiers.
4123 *
4124 *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4125 *
4126 * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
4127 * 	Description
4128 * 		**bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
4129 * 		The *m* represents the seq_file. The *data* and *len* represent the
4130 * 		data to write in bytes.
4131 * 	Return
4132 * 		0 on success, or a negative error in case of failure:
4133 *
4134 *		**-EOVERFLOW** if an overflow happened: The same object will be tried again.
4135 *
4136 * u64 bpf_sk_cgroup_id(void *sk)
4137 *	Description
4138 *		Return the cgroup v2 id of the socket *sk*.
4139 *
4140 *		*sk* must be a non-**NULL** pointer to a socket, e.g. one
4141 *		returned from **bpf_sk_lookup_xxx**\ (),
4142 *		**bpf_sk_fullsock**\ (), etc. The format of returned id is
4143 *		same as in **bpf_skb_cgroup_id**\ ().
4144 *
4145 *		This helper is available only if the kernel was compiled with
4146 *		the **CONFIG_SOCK_CGROUP_DATA** configuration option.
4147 *	Return
4148 *		The id is returned or 0 in case the id could not be retrieved.
4149 *
4150 * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4151 *	Description
4152 *		Return id of cgroup v2 that is ancestor of cgroup associated
4153 *		with the *sk* at the *ancestor_level*.  The root cgroup is at
4154 *		*ancestor_level* zero and each step down the hierarchy
4155 *		increments the level. If *ancestor_level* == level of cgroup
4156 *		associated with *sk*, then return value will be same as that
4157 *		of **bpf_sk_cgroup_id**\ ().
4158 *
4159 *		The helper is useful to implement policies based on cgroups
4160 *		that are upper in hierarchy than immediate cgroup associated
4161 *		with *sk*.
4162 *
4163 *		The format of returned id and helper limitations are same as in
4164 *		**bpf_sk_cgroup_id**\ ().
4165 *	Return
4166 *		The id is returned or 0 in case the id could not be retrieved.
4167 *
4168 * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
4169 * 	Description
4170 * 		Copy *size* bytes from *data* into a ring buffer *ringbuf*.
4171 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4172 * 		of new data availability is sent.
4173 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4174 * 		of new data availability is sent unconditionally.
4175 * 		If **0** is specified in *flags*, an adaptive notification
4176 * 		of new data availability is sent.
4177 *
4178 * 		An adaptive notification is a notification sent whenever the user-space
4179 * 		process has caught up and consumed all available payloads. In case the user-space
4180 * 		process is still processing a previous payload, then no notification is needed
4181 * 		as it will process the newly added payload automatically.
4182 * 	Return
4183 * 		0 on success, or a negative error in case of failure.
4184 *
4185 * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
4186 * 	Description
4187 * 		Reserve *size* bytes of payload in a ring buffer *ringbuf*.
4188 * 		*flags* must be 0.
4189 * 	Return
4190 * 		Valid pointer with *size* bytes of memory available; NULL,
4191 * 		otherwise.
4192 *
4193 * void bpf_ringbuf_submit(void *data, u64 flags)
4194 * 	Description
4195 * 		Submit reserved ring buffer sample, pointed to by *data*.
4196 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4197 * 		of new data availability is sent.
4198 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4199 * 		of new data availability is sent unconditionally.
4200 * 		If **0** is specified in *flags*, an adaptive notification
4201 * 		of new data availability is sent.
4202 *
4203 * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4204 * 	Return
4205 * 		Nothing. Always succeeds.
4206 *
4207 * void bpf_ringbuf_discard(void *data, u64 flags)
4208 * 	Description
4209 * 		Discard reserved ring buffer sample, pointed to by *data*.
4210 * 		If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4211 * 		of new data availability is sent.
4212 * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4213 * 		of new data availability is sent unconditionally.
4214 * 		If **0** is specified in *flags*, an adaptive notification
4215 * 		of new data availability is sent.
4216 *
4217 * 		See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4218 * 	Return
4219 * 		Nothing. Always succeeds.
4220 *
4221 * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4222 *	Description
4223 *		Query various characteristics of provided ring buffer. What
4224 *		exactly is queries is determined by *flags*:
4225 *
4226 *		* **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
4227 *		* **BPF_RB_RING_SIZE**: The size of ring buffer.
4228 *		* **BPF_RB_CONS_POS**: Consumer position (can wrap around).
4229 *		* **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
4230 *
4231 *		Data returned is just a momentary snapshot of actual values
4232 *		and could be inaccurate, so this facility should be used to
4233 *		power heuristics and for reporting, not to make 100% correct
4234 *		calculation.
4235 *	Return
4236 *		Requested value, or 0, if *flags* are not recognized.
4237 *
4238 * long bpf_csum_level(struct sk_buff *skb, u64 level)
4239 * 	Description
4240 * 		Change the skbs checksum level by one layer up or down, or
4241 * 		reset it entirely to none in order to have the stack perform
4242 * 		checksum validation. The level is applicable to the following
4243 * 		protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4244 * 		| ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
4245 * 		through **bpf_skb_adjust_room**\ () helper with passing in
4246 * 		**BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one	call
4247 * 		to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
4248 * 		the UDP header is removed. Similarly, an encap of the latter
4249 * 		into the former could be accompanied by a helper call to
4250 * 		**bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
4251 * 		skb is still intended to be processed in higher layers of the
4252 * 		stack instead of just egressing at tc.
4253 *
4254 * 		There are three supported level settings at this time:
4255 *
4256 * 		* **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
4257 * 		  with CHECKSUM_UNNECESSARY.
4258 * 		* **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
4259 * 		  with CHECKSUM_UNNECESSARY.
4260 * 		* **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
4261 * 		  sets CHECKSUM_NONE to force checksum validation by the stack.
4262 * 		* **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
4263 * 		  skb->csum_level.
4264 * 	Return
4265 * 		0 on success, or a negative error in case of failure. In the
4266 * 		case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
4267 * 		is returned or the error code -EACCES in case the skb is not
4268 * 		subject to CHECKSUM_UNNECESSARY.
4269 *
4270 * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
4271 *	Description
4272 *		Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
4273 *	Return
4274 *		*sk* if casting is valid, or **NULL** otherwise.
4275 *
4276 * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
4277 *	Description
4278 *		Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
4279 *	Return
4280 *		*sk* if casting is valid, or **NULL** otherwise.
4281 *
4282 * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
4283 * 	Description
4284 *		Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
4285 *	Return
4286 *		*sk* if casting is valid, or **NULL** otherwise.
4287 *
4288 * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
4289 * 	Description
4290 *		Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
4291 *	Return
4292 *		*sk* if casting is valid, or **NULL** otherwise.
4293 *
4294 * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
4295 * 	Description
4296 *		Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
4297 *	Return
4298 *		*sk* if casting is valid, or **NULL** otherwise.
4299 *
4300 * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
4301 *	Description
4302 *		Return a user or a kernel stack in bpf program provided buffer.
4303 *		To achieve this, the helper needs *task*, which is a valid
4304 *		pointer to **struct task_struct**. To store the stacktrace, the
4305 *		bpf program provides *buf* with a nonnegative *size*.
4306 *
4307 *		The last argument, *flags*, holds the number of stack frames to
4308 *		skip (from 0 to 255), masked with
4309 *		**BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
4310 *		the following flags:
4311 *
4312 *		**BPF_F_USER_STACK**
4313 *			Collect a user space stack instead of a kernel stack.
4314 *		**BPF_F_USER_BUILD_ID**
4315 *			Collect buildid+offset instead of ips for user stack,
4316 *			only valid if **BPF_F_USER_STACK** is also specified.
4317 *
4318 *		**bpf_get_task_stack**\ () can collect up to
4319 *		**PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
4320 *		to sufficient large buffer size. Note that
4321 *		this limit can be controlled with the **sysctl** program, and
4322 *		that it should be manually increased in order to profile long
4323 *		user stacks (such as stacks for Java programs). To do so, use:
4324 *
4325 *		::
4326 *
4327 *			# sysctl kernel.perf_event_max_stack=<new value>
4328 *	Return
4329 * 		The non-negative copied *buf* length equal to or less than
4330 * 		*size* on success, or a negative error in case of failure.
4331 *
4332 * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
4333 *	Description
4334 *		Load header option.  Support reading a particular TCP header
4335 *		option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
4336 *
4337 *		If *flags* is 0, it will search the option from the
4338 *		*skops*\ **->skb_data**.  The comment in **struct bpf_sock_ops**
4339 *		has details on what skb_data contains under different
4340 *		*skops*\ **->op**.
4341 *
4342 *		The first byte of the *searchby_res* specifies the
4343 *		kind that it wants to search.
4344 *
4345 *		If the searching kind is an experimental kind
4346 *		(i.e. 253 or 254 according to RFC6994).  It also
4347 *		needs to specify the "magic" which is either
4348 *		2 bytes or 4 bytes.  It then also needs to
4349 *		specify the size of the magic by using
4350 *		the 2nd byte which is "kind-length" of a TCP
4351 *		header option and the "kind-length" also
4352 *		includes the first 2 bytes "kind" and "kind-length"
4353 *		itself as a normal TCP header option also does.
4354 *
4355 *		For example, to search experimental kind 254 with
4356 *		2 byte magic 0xeB9F, the searchby_res should be
4357 *		[ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4358 *
4359 *		To search for the standard window scale option (3),
4360 *		the *searchby_res* should be [ 3, 0, 0, .... 0 ].
4361 *		Note, kind-length must be 0 for regular option.
4362 *
4363 *		Searching for No-Op (0) and End-of-Option-List (1) are
4364 *		not supported.
4365 *
4366 *		*len* must be at least 2 bytes which is the minimal size
4367 *		of a header option.
4368 *
4369 *		Supported flags:
4370 *
4371 *		* **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
4372 *		  saved_syn packet or the just-received syn packet.
4373 *
4374 *	Return
4375 *		> 0 when found, the header option is copied to *searchby_res*.
4376 *		The return value is the total length copied. On failure, a
4377 *		negative error code is returned:
4378 *
4379 *		**-EINVAL** if a parameter is invalid.
4380 *
4381 *		**-ENOMSG** if the option is not found.
4382 *
4383 *		**-ENOENT** if no syn packet is available when
4384 *		**BPF_LOAD_HDR_OPT_TCP_SYN** is used.
4385 *
4386 *		**-ENOSPC** if there is not enough space.  Only *len* number of
4387 *		bytes are copied.
4388 *
4389 *		**-EFAULT** on failure to parse the header options in the
4390 *		packet.
4391 *
4392 *		**-EPERM** if the helper cannot be used under the current
4393 *		*skops*\ **->op**.
4394 *
4395 * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
4396 *	Description
4397 *		Store header option.  The data will be copied
4398 *		from buffer *from* with length *len* to the TCP header.
4399 *
4400 *		The buffer *from* should have the whole option that
4401 *		includes the kind, kind-length, and the actual
4402 *		option data.  The *len* must be at least kind-length
4403 *		long.  The kind-length does not have to be 4 byte
4404 *		aligned.  The kernel will take care of the padding
4405 *		and setting the 4 bytes aligned value to th->doff.
4406 *
4407 *		This helper will check for duplicated option
4408 *		by searching the same option in the outgoing skb.
4409 *
4410 *		This helper can only be called during
4411 *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4412 *
4413 *	Return
4414 *		0 on success, or negative error in case of failure:
4415 *
4416 *		**-EINVAL** If param is invalid.
4417 *
4418 *		**-ENOSPC** if there is not enough space in the header.
4419 *		Nothing has been written
4420 *
4421 *		**-EEXIST** if the option already exists.
4422 *
4423 *		**-EFAULT** on failrue to parse the existing header options.
4424 *
4425 *		**-EPERM** if the helper cannot be used under the current
4426 *		*skops*\ **->op**.
4427 *
4428 * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4429 *	Description
4430 *		Reserve *len* bytes for the bpf header option.  The
4431 *		space will be used by **bpf_store_hdr_opt**\ () later in
4432 *		**BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4433 *
4434 *		If **bpf_reserve_hdr_opt**\ () is called multiple times,
4435 *		the total number of bytes will be reserved.
4436 *
4437 *		This helper can only be called during
4438 *		**BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
4439 *
4440 *	Return
4441 *		0 on success, or negative error in case of failure:
4442 *
4443 *		**-EINVAL** if a parameter is invalid.
4444 *
4445 *		**-ENOSPC** if there is not enough space in the header.
4446 *
4447 *		**-EPERM** if the helper cannot be used under the current
4448 *		*skops*\ **->op**.
4449 *
4450 * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
4451 *	Description
4452 *		Get a bpf_local_storage from an *inode*.
4453 *
4454 *		Logically, it could be thought of as getting the value from
4455 *		a *map* with *inode* as the **key**.  From this
4456 *		perspective,  the usage is not much different from
4457 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
4458 *		helper enforces the key must be an inode and the map must also
4459 *		be a **BPF_MAP_TYPE_INODE_STORAGE**.
4460 *
4461 *		Underneath, the value is stored locally at *inode* instead of
4462 *		the *map*.  The *map* is used as the bpf-local-storage
4463 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4464 *		searched against all bpf_local_storage residing at *inode*.
4465 *
4466 *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4467 *		used such that a new bpf_local_storage will be
4468 *		created if one does not exist.  *value* can be used
4469 *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4470 *		the initial value of a bpf_local_storage.  If *value* is
4471 *		**NULL**, the new bpf_local_storage will be zero initialized.
4472 *	Return
4473 *		A bpf_local_storage pointer is returned on success.
4474 *
4475 *		**NULL** if not found or there was an error in adding
4476 *		a new bpf_local_storage.
4477 *
4478 * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
4479 *	Description
4480 *		Delete a bpf_local_storage from an *inode*.
4481 *	Return
4482 *		0 on success.
4483 *
4484 *		**-ENOENT** if the bpf_local_storage cannot be found.
4485 *
4486 * long bpf_d_path(struct path *path, char *buf, u32 sz)
4487 *	Description
4488 *		Return full path for given **struct path** object, which
4489 *		needs to be the kernel BTF *path* object. The path is
4490 *		returned in the provided buffer *buf* of size *sz* and
4491 *		is zero terminated.
4492 *
4493 *	Return
4494 *		On success, the strictly positive length of the string,
4495 *		including the trailing NUL character. On error, a negative
4496 *		value.
4497 *
4498 * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
4499 * 	Description
4500 * 		Read *size* bytes from user space address *user_ptr* and store
4501 * 		the data in *dst*. This is a wrapper of **copy_from_user**\ ().
4502 * 	Return
4503 * 		0 on success, or a negative error in case of failure.
4504 *
4505 * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
4506 *	Description
4507 *		Use BTF to store a string representation of *ptr*->ptr in *str*,
4508 *		using *ptr*->type_id.  This value should specify the type
4509 *		that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4510 *		can be used to look up vmlinux BTF type ids. Traversing the
4511 *		data structure using BTF, the type information and values are
4512 *		stored in the first *str_size* - 1 bytes of *str*.  Safe copy of
4513 *		the pointer data is carried out to avoid kernel crashes during
4514 *		operation.  Smaller types can use string space on the stack;
4515 *		larger programs can use map data to store the string
4516 *		representation.
4517 *
4518 *		The string can be subsequently shared with userspace via
4519 *		bpf_perf_event_output() or ring buffer interfaces.
4520 *		bpf_trace_printk() is to be avoided as it places too small
4521 *		a limit on string size to be useful.
4522 *
4523 *		*flags* is a combination of
4524 *
4525 *		**BTF_F_COMPACT**
4526 *			no formatting around type information
4527 *		**BTF_F_NONAME**
4528 *			no struct/union member names/types
4529 *		**BTF_F_PTR_RAW**
4530 *			show raw (unobfuscated) pointer values;
4531 *			equivalent to printk specifier %px.
4532 *		**BTF_F_ZERO**
4533 *			show zero-valued struct/union members; they
4534 *			are not displayed by default
4535 *
4536 *	Return
4537 *		The number of bytes that were written (or would have been
4538 *		written if output had to be truncated due to string size),
4539 *		or a negative error in cases of failure.
4540 *
4541 * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
4542 *	Description
4543 *		Use BTF to write to seq_write a string representation of
4544 *		*ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
4545 *		*flags* are identical to those used for bpf_snprintf_btf.
4546 *	Return
4547 *		0 on success or a negative error in case of failure.
4548 *
4549 * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4550 * 	Description
4551 * 		See **bpf_get_cgroup_classid**\ () for the main description.
4552 * 		This helper differs from **bpf_get_cgroup_classid**\ () in that
4553 * 		the cgroup v1 net_cls class is retrieved only from the *skb*'s
4554 * 		associated socket instead of the current process.
4555 * 	Return
4556 * 		The id is returned or 0 in case the id could not be retrieved.
4557 *
4558 * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4559 * 	Description
4560 * 		Redirect the packet to another net device of index *ifindex*
4561 * 		and fill in L2 addresses from neighboring subsystem. This helper
4562 * 		is somewhat similar to **bpf_redirect**\ (), except that it
4563 * 		populates L2 addresses as well, meaning, internally, the helper
4564 * 		relies on the neighbor lookup for the L2 address of the nexthop.
4565 *
4566 * 		The helper will perform a FIB lookup based on the skb's
4567 * 		networking header to get the address of the next hop, unless
4568 * 		this is supplied by the caller in the *params* argument. The
4569 * 		*plen* argument indicates the len of *params* and should be set
4570 * 		to 0 if *params* is NULL.
4571 *
4572 * 		The *flags* argument is reserved and must be 0. The helper is
4573 * 		currently only supported for tc BPF program types, and enabled
4574 * 		for IPv4 and IPv6 protocols.
4575 * 	Return
4576 * 		The helper returns **TC_ACT_REDIRECT** on success or
4577 * 		**TC_ACT_SHOT** on error.
4578 *
4579 * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
4580 *     Description
4581 *             Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4582 *             pointer to the percpu kernel variable on *cpu*. A ksym is an
4583 *             extern variable decorated with '__ksym'. For ksym, there is a
4584 *             global var (either static or global) defined of the same name
4585 *             in the kernel. The ksym is percpu if the global var is percpu.
4586 *             The returned pointer points to the global percpu var on *cpu*.
4587 *
4588 *             bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4589 *             kernel, except that bpf_per_cpu_ptr() may return NULL. This
4590 *             happens if *cpu* is larger than nr_cpu_ids. The caller of
4591 *             bpf_per_cpu_ptr() must check the returned value.
4592 *     Return
4593 *             A pointer pointing to the kernel percpu variable on *cpu*, or
4594 *             NULL, if *cpu* is invalid.
4595 *
4596 * void *bpf_this_cpu_ptr(const void *percpu_ptr)
4597 *	Description
4598 *		Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4599 *		pointer to the percpu kernel variable on this cpu. See the
4600 *		description of 'ksym' in **bpf_per_cpu_ptr**\ ().
4601 *
4602 *		bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4603 *		the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
4604 *		never return NULL.
4605 *	Return
4606 *		A pointer pointing to the kernel percpu variable on this cpu.
4607 *
4608 * long bpf_redirect_peer(u32 ifindex, u64 flags)
4609 * 	Description
4610 * 		Redirect the packet to another net device of index *ifindex*.
4611 * 		This helper is somewhat similar to **bpf_redirect**\ (), except
4612 * 		that the redirection happens to the *ifindex*' peer device and
4613 * 		the netns switch takes place from ingress to ingress without
4614 * 		going through the CPU's backlog queue.
4615 *
4616 * 		The *flags* argument is reserved and must be 0. The helper is
4617 * 		currently only supported for tc BPF program types at the ingress
4618 * 		hook and for veth device types. The peer device must reside in a
4619 * 		different network namespace.
4620 * 	Return
4621 * 		The helper returns **TC_ACT_REDIRECT** on success or
4622 * 		**TC_ACT_SHOT** on error.
4623 *
4624 * void *bpf_task_storage_get(struct bpf_map *map, struct task_struct *task, void *value, u64 flags)
4625 *	Description
4626 *		Get a bpf_local_storage from the *task*.
4627 *
4628 *		Logically, it could be thought of as getting the value from
4629 *		a *map* with *task* as the **key**.  From this
4630 *		perspective,  the usage is not much different from
4631 *		**bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
4632 *		helper enforces the key must be an task_struct and the map must also
4633 *		be a **BPF_MAP_TYPE_TASK_STORAGE**.
4634 *
4635 *		Underneath, the value is stored locally at *task* instead of
4636 *		the *map*.  The *map* is used as the bpf-local-storage
4637 *		"type". The bpf-local-storage "type" (i.e. the *map*) is
4638 *		searched against all bpf_local_storage residing at *task*.
4639 *
4640 *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4641 *		used such that a new bpf_local_storage will be
4642 *		created if one does not exist.  *value* can be used
4643 *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4644 *		the initial value of a bpf_local_storage.  If *value* is
4645 *		**NULL**, the new bpf_local_storage will be zero initialized.
4646 *	Return
4647 *		A bpf_local_storage pointer is returned on success.
4648 *
4649 *		**NULL** if not found or there was an error in adding
4650 *		a new bpf_local_storage.
4651 *
4652 * long bpf_task_storage_delete(struct bpf_map *map, struct task_struct *task)
4653 *	Description
4654 *		Delete a bpf_local_storage from a *task*.
4655 *	Return
4656 *		0 on success.
4657 *
4658 *		**-ENOENT** if the bpf_local_storage cannot be found.
4659 *
4660 * struct task_struct *bpf_get_current_task_btf(void)
4661 *	Description
4662 *		Return a BTF pointer to the "current" task.
4663 *		This pointer can also be used in helpers that accept an
4664 *		*ARG_PTR_TO_BTF_ID* of type *task_struct*.
4665 *	Return
4666 *		Pointer to the current task.
4667 *
4668 * long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4669 *	Description
4670 *		Set or clear certain options on *bprm*:
4671 *
4672 *		**BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
4673 *		which sets the **AT_SECURE** auxv for glibc. The bit
4674 *		is cleared if the flag is not specified.
4675 *	Return
4676 *		**-EINVAL** if invalid *flags* are passed, zero otherwise.
4677 *
4678 * u64 bpf_ktime_get_coarse_ns(void)
4679 * 	Description
4680 * 		Return a coarse-grained version of the time elapsed since
4681 * 		system boot, in nanoseconds. Does not include time the system
4682 * 		was suspended.
4683 *
4684 * 		See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
4685 * 	Return
4686 * 		Current *ktime*.
4687 *
4688 * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
4689 *	Description
4690 *		Returns the stored IMA hash of the *inode* (if it's avaialable).
4691 *		If the hash is larger than *size*, then only *size*
4692 *		bytes will be copied to *dst*
4693 *	Return
4694 *		The **hash_algo** is returned on success,
4695 *		**-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
4696 *		invalid arguments are passed.
4697 *
4698 * struct socket *bpf_sock_from_file(struct file *file)
4699 *	Description
4700 *		If the given file represents a socket, returns the associated
4701 *		socket.
4702 *	Return
4703 *		A pointer to a struct socket on success or NULL if the file is
4704 *		not a socket.
4705 *
4706 * long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
4707 *	Description
4708 *		Check packet size against exceeding MTU of net device (based
4709 *		on *ifindex*).  This helper will likely be used in combination
4710 *		with helpers that adjust/change the packet size.
4711 *
4712 *		The argument *len_diff* can be used for querying with a planned
4713 *		size change. This allows to check MTU prior to changing packet
4714 *		ctx. Providing an *len_diff* adjustment that is larger than the
4715 *		actual packet size (resulting in negative packet size) will in
4716 *		principle not exceed the MTU, why it is not considered a
4717 *		failure.  Other BPF-helpers are needed for performing the
4718 *		planned size change, why the responsability for catch a negative
4719 *		packet size belong in those helpers.
4720 *
4721 *		Specifying *ifindex* zero means the MTU check is performed
4722 *		against the current net device.  This is practical if this isn't
4723 *		used prior to redirect.
4724 *
4725 *		On input *mtu_len* must be a valid pointer, else verifier will
4726 *		reject BPF program.  If the value *mtu_len* is initialized to
4727 *		zero then the ctx packet size is use.  When value *mtu_len* is
4728 *		provided as input this specify the L3 length that the MTU check
4729 *		is done against. Remember XDP and TC length operate at L2, but
4730 *		this value is L3 as this correlate to MTU and IP-header tot_len
4731 *		values which are L3 (similar behavior as bpf_fib_lookup).
4732 *
4733 *		The Linux kernel route table can configure MTUs on a more
4734 *		specific per route level, which is not provided by this helper.
4735 *		For route level MTU checks use the **bpf_fib_lookup**\ ()
4736 *		helper.
4737 *
4738 *		*ctx* is either **struct xdp_md** for XDP programs or
4739 *		**struct sk_buff** for tc cls_act programs.
4740 *
4741 *		The *flags* argument can be a combination of one or more of the
4742 *		following values:
4743 *
4744 *		**BPF_MTU_CHK_SEGS**
4745 *			This flag will only works for *ctx* **struct sk_buff**.
4746 *			If packet context contains extra packet segment buffers
4747 *			(often knows as GSO skb), then MTU check is harder to
4748 *			check at this point, because in transmit path it is
4749 *			possible for the skb packet to get re-segmented
4750 *			(depending on net device features).  This could still be
4751 *			a MTU violation, so this flag enables performing MTU
4752 *			check against segments, with a different violation
4753 *			return code to tell it apart. Check cannot use len_diff.
4754 *
4755 *		On return *mtu_len* pointer contains the MTU value of the net
4756 *		device.  Remember the net device configured MTU is the L3 size,
4757 *		which is returned here and XDP and TC length operate at L2.
4758 *		Helper take this into account for you, but remember when using
4759 *		MTU value in your BPF-code.
4760 *
4761 *	Return
4762 *		* 0 on success, and populate MTU value in *mtu_len* pointer.
4763 *
4764 *		* < 0 if any input argument is invalid (*mtu_len* not updated)
4765 *
4766 *		MTU violations return positive values, but also populate MTU
4767 *		value in *mtu_len* pointer, as this can be needed for
4768 *		implementing PMTU handing:
4769 *
4770 *		* **BPF_MTU_CHK_RET_FRAG_NEEDED**
4771 *		* **BPF_MTU_CHK_RET_SEGS_TOOBIG**
4772 *
4773 * long bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, void *callback_ctx, u64 flags)
4774 *	Description
4775 *		For each element in **map**, call **callback_fn** function with
4776 *		**map**, **callback_ctx** and other map-specific parameters.
4777 *		The **callback_fn** should be a static function and
4778 *		the **callback_ctx** should be a pointer to the stack.
4779 *		The **flags** is used to control certain aspects of the helper.
4780 *		Currently, the **flags** must be 0.
4781 *
4782 *		The following are a list of supported map types and their
4783 *		respective expected callback signatures:
4784 *
4785 *		BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4786 *		BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4787 *		BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4788 *
4789 *		long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
4790 *
4791 *		For per_cpu maps, the map_value is the value on the cpu where the
4792 *		bpf_prog is running.
4793 *
4794 *		If **callback_fn** return 0, the helper will continue to the next
4795 *		element. If return value is 1, the helper will skip the rest of
4796 *		elements and return. Other return values are not used now.
4797 *
4798 *	Return
4799 *		The number of traversed map elements for success, **-EINVAL** for
4800 *		invalid **flags**.
4801 *
4802 * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len)
4803 *	Description
4804 *		Outputs a string into the **str** buffer of size **str_size**
4805 *		based on a format string stored in a read-only map pointed by
4806 *		**fmt**.
4807 *
4808 *		Each format specifier in **fmt** corresponds to one u64 element
4809 *		in the **data** array. For strings and pointers where pointees
4810 *		are accessed, only the pointer values are stored in the *data*
4811 *		array. The *data_len* is the size of *data* in bytes - must be
4812 *		a multiple of 8.
4813 *
4814 *		Formats **%s** and **%p{i,I}{4,6}** require to read kernel
4815 *		memory. Reading kernel memory may fail due to either invalid
4816 *		address or valid address but requiring a major memory fault. If
4817 *		reading kernel memory fails, the string for **%s** will be an
4818 *		empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
4819 *		Not returning error to bpf program is consistent with what
4820 *		**bpf_trace_printk**\ () does for now.
4821 *
4822 *	Return
4823 *		The strictly positive length of the formatted string, including
4824 *		the trailing zero character. If the return value is greater than
4825 *		**str_size**, **str** contains a truncated string, guaranteed to
4826 *		be zero-terminated except when **str_size** is 0.
4827 *
4828 *		Or **-EBUSY** if the per-CPU memory copy buffer is busy.
4829 *
4830 * long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4831 * 	Description
4832 * 		Execute bpf syscall with given arguments.
4833 * 	Return
4834 * 		A syscall result.
4835 *
4836 * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4837 * 	Description
4838 * 		Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4839 * 	Return
4840 * 		Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4841 *
4842 * long bpf_sys_close(u32 fd)
4843 * 	Description
4844 * 		Execute close syscall for given FD.
4845 * 	Return
4846 * 		A syscall result.
4847 *
4848 * long bpf_timer_init(struct bpf_timer *timer, struct bpf_map *map, u64 flags)
4849 *	Description
4850 *		Initialize the timer.
4851 *		First 4 bits of *flags* specify clockid.
4852 *		Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4853 *		All other bits of *flags* are reserved.
4854 *		The verifier will reject the program if *timer* is not from
4855 *		the same *map*.
4856 *	Return
4857 *		0 on success.
4858 *		**-EBUSY** if *timer* is already initialized.
4859 *		**-EINVAL** if invalid *flags* are passed.
4860 *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4861 *		The user space should either hold a file descriptor to a map with timers
4862 *		or pin such map in bpffs. When map is unpinned or file descriptor is
4863 *		closed all timers in the map will be cancelled and freed.
4864 *
4865 * long bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn)
4866 *	Description
4867 *		Configure the timer to call *callback_fn* static function.
4868 *	Return
4869 *		0 on success.
4870 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4871 *		**-EPERM** if *timer* is in a map that doesn't have any user references.
4872 *		The user space should either hold a file descriptor to a map with timers
4873 *		or pin such map in bpffs. When map is unpinned or file descriptor is
4874 *		closed all timers in the map will be cancelled and freed.
4875 *
4876 * long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4877 *	Description
4878 *		Set timer expiration N nanoseconds from the current time. The
4879 *		configured callback will be invoked in soft irq context on some cpu
4880 *		and will not repeat unless another bpf_timer_start() is made.
4881 *		In such case the next invocation can migrate to a different cpu.
4882 *		Since struct bpf_timer is a field inside map element the map
4883 *		owns the timer. The bpf_timer_set_callback() will increment refcnt
4884 *		of BPF program to make sure that callback_fn code stays valid.
4885 *		When user space reference to a map reaches zero all timers
4886 *		in a map are cancelled and corresponding program's refcnts are
4887 *		decremented. This is done to make sure that Ctrl-C of a user
4888 *		process doesn't leave any timers running. If map is pinned in
4889 *		bpffs the callback_fn can re-arm itself indefinitely.
4890 *		bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4891 *		cancel and free the timer in the given map element.
4892 *		The map can contain timers that invoke callback_fn-s from different
4893 *		programs. The same callback_fn can serve different timers from
4894 *		different maps if key/value layout matches across maps.
4895 *		Every bpf_timer_set_callback() can have different callback_fn.
4896 *
4897 *	Return
4898 *		0 on success.
4899 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
4900 *		or invalid *flags* are passed.
4901 *
4902 * long bpf_timer_cancel(struct bpf_timer *timer)
4903 *	Description
4904 *		Cancel the timer and wait for callback_fn to finish if it was running.
4905 *	Return
4906 *		0 if the timer was not active.
4907 *		1 if the timer was active.
4908 *		**-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4909 *		**-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
4910 *		own timer which would have led to a deadlock otherwise.
4911 *
4912 * u64 bpf_get_func_ip(void *ctx)
4913 * 	Description
4914 * 		Get address of the traced function (for tracing and kprobe programs).
4915 * 	Return
4916 * 		Address of the traced function.
4917 *
4918 * u64 bpf_get_attach_cookie(void *ctx)
4919 * 	Description
4920 * 		Get bpf_cookie value provided (optionally) during the program
4921 * 		attachment. It might be different for each individual
4922 * 		attachment, even if BPF program itself is the same.
4923 * 		Expects BPF program context *ctx* as a first argument.
4924 *
4925 * 		Supported for the following program types:
4926 *			- kprobe/uprobe;
4927 *			- tracepoint;
4928 *			- perf_event.
4929 * 	Return
4930 *		Value specified by user at BPF link creation/attachment time
4931 *		or 0, if it was not specified.
4932 *
4933 * long bpf_task_pt_regs(struct task_struct *task)
4934 *	Description
4935 *		Get the struct pt_regs associated with **task**.
4936 *	Return
4937 *		A pointer to struct pt_regs.
4938 *
4939 * long bpf_get_branch_snapshot(void *entries, u32 size, u64 flags)
4940 *	Description
4941 *		Get branch trace from hardware engines like Intel LBR. The
4942 *		hardware engine is stopped shortly after the helper is
4943 *		called. Therefore, the user need to filter branch entries
4944 *		based on the actual use case. To capture branch trace
4945 *		before the trigger point of the BPF program, the helper
4946 *		should be called at the beginning of the BPF program.
4947 *
4948 *		The data is stored as struct perf_branch_entry into output
4949 *		buffer *entries*. *size* is the size of *entries* in bytes.
4950 *		*flags* is reserved for now and must be zero.
4951 *
4952 *	Return
4953 *		On success, number of bytes written to *buf*. On error, a
4954 *		negative value.
4955 *
4956 *		**-EINVAL** if *flags* is not zero.
4957 *
4958 *		**-ENOENT** if architecture does not support branch records.
4959 *
4960 * long bpf_trace_vprintk(const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4961 *	Description
4962 *		Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64
4963 *		to format and can handle more format args as a result.
4964 *
4965 *		Arguments are to be used as in **bpf_seq_printf**\ () helper.
4966 *	Return
4967 *		The number of bytes written to the buffer, or a negative error
4968 *		in case of failure.
4969 *
4970 * struct unix_sock *bpf_skc_to_unix_sock(void *sk)
4971 * 	Description
4972 *		Dynamically cast a *sk* pointer to a *unix_sock* pointer.
4973 *	Return
4974 *		*sk* if casting is valid, or **NULL** otherwise.
4975 *
4976 * long bpf_kallsyms_lookup_name(const char *name, int name_sz, int flags, u64 *res)
4977 *	Description
4978 *		Get the address of a kernel symbol, returned in *res*. *res* is
4979 *		set to 0 if the symbol is not found.
4980 *	Return
4981 *		On success, zero. On error, a negative value.
4982 *
4983 *		**-EINVAL** if *flags* is not zero.
4984 *
4985 *		**-EINVAL** if string *name* is not the same size as *name_sz*.
4986 *
4987 *		**-ENOENT** if symbol is not found.
4988 *
4989 *		**-EPERM** if caller does not have permission to obtain kernel address.
4990 *
4991 * long bpf_find_vma(struct task_struct *task, u64 addr, void *callback_fn, void *callback_ctx, u64 flags)
4992 *	Description
4993 *		Find vma of *task* that contains *addr*, call *callback_fn*
4994 *		function with *task*, *vma*, and *callback_ctx*.
4995 *		The *callback_fn* should be a static function and
4996 *		the *callback_ctx* should be a pointer to the stack.
4997 *		The *flags* is used to control certain aspects of the helper.
4998 *		Currently, the *flags* must be 0.
4999 *
5000 *		The expected callback signature is
5001 *
5002 *		long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
5003 *
5004 *	Return
5005 *		0 on success.
5006 *		**-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
5007 *		**-EBUSY** if failed to try lock mmap_lock.
5008 *		**-EINVAL** for invalid **flags**.
5009 *
5010 * long bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx, u64 flags)
5011 *	Description
5012 *		For **nr_loops**, call **callback_fn** function
5013 *		with **callback_ctx** as the context parameter.
5014 *		The **callback_fn** should be a static function and
5015 *		the **callback_ctx** should be a pointer to the stack.
5016 *		The **flags** is used to control certain aspects of the helper.
5017 *		Currently, the **flags** must be 0. Currently, nr_loops is
5018 *		limited to 1 << 23 (~8 million) loops.
5019 *
5020 *		long (\*callback_fn)(u32 index, void \*ctx);
5021 *
5022 *		where **index** is the current index in the loop. The index
5023 *		is zero-indexed.
5024 *
5025 *		If **callback_fn** returns 0, the helper will continue to the next
5026 *		loop. If return value is 1, the helper will skip the rest of
5027 *		the loops and return. Other return values are not used now,
5028 *		and will be rejected by the verifier.
5029 *
5030 *	Return
5031 *		The number of loops performed, **-EINVAL** for invalid **flags**,
5032 *		**-E2BIG** if **nr_loops** exceeds the maximum number of loops.
5033 *
5034 * long bpf_strncmp(const char *s1, u32 s1_sz, const char *s2)
5035 *	Description
5036 *		Do strncmp() between **s1** and **s2**. **s1** doesn't need
5037 *		to be null-terminated and **s1_sz** is the maximum storage
5038 *		size of **s1**. **s2** must be a read-only string.
5039 *	Return
5040 *		An integer less than, equal to, or greater than zero
5041 *		if the first **s1_sz** bytes of **s1** is found to be
5042 *		less than, to match, or be greater than **s2**.
5043 *
5044 * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
5045 *	Description
5046 *		Get **n**-th argument (zero based) of the traced function (for tracing programs)
5047 *		returned in **value**.
5048 *
5049 *	Return
5050 *		0 on success.
5051 *		**-EINVAL** if n >= arguments count of traced function.
5052 *
5053 * long bpf_get_func_ret(void *ctx, u64 *value)
5054 *	Description
5055 *		Get return value of the traced function (for tracing programs)
5056 *		in **value**.
5057 *
5058 *	Return
5059 *		0 on success.
5060 *		**-EOPNOTSUPP** for tracing programs other than BPF_TRACE_FEXIT or BPF_MODIFY_RETURN.
5061 *
5062 * long bpf_get_func_arg_cnt(void *ctx)
5063 *	Description
5064 *		Get number of arguments of the traced function (for tracing programs).
5065 *
5066 *	Return
5067 *		The number of arguments of the traced function.
5068 *
5069 * int bpf_get_retval(void)
5070 *	Description
5071 *		Get the syscall's return value that will be returned to userspace.
5072 *
5073 *		This helper is currently supported by cgroup programs only.
5074 *	Return
5075 *		The syscall's return value.
5076 *
5077 * int bpf_set_retval(int retval)
5078 *	Description
5079 *		Set the syscall's return value that will be returned to userspace.
5080 *
5081 *		This helper is currently supported by cgroup programs only.
5082 *	Return
5083 *		0 on success, or a negative error in case of failure.
5084 *
5085 * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)
5086 *	Description
5087 *		Get the total size of a given xdp buff (linear and paged area)
5088 *	Return
5089 *		The total size of a given xdp buffer.
5090 *
5091 * long bpf_xdp_load_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
5092 *	Description
5093 *		This helper is provided as an easy way to load data from a
5094 *		xdp buffer. It can be used to load *len* bytes from *offset* from
5095 *		the frame associated to *xdp_md*, into the buffer pointed by
5096 *		*buf*.
5097 *	Return
5098 *		0 on success, or a negative error in case of failure.
5099 *
5100 * long bpf_xdp_store_bytes(struct xdp_buff *xdp_md, u32 offset, void *buf, u32 len)
5101 *	Description
5102 *		Store *len* bytes from buffer *buf* into the frame
5103 *		associated to *xdp_md*, at *offset*.
5104 *	Return
5105 *		0 on success, or a negative error in case of failure.
5106 *
5107 * long bpf_copy_from_user_task(void *dst, u32 size, const void *user_ptr, struct task_struct *tsk, u64 flags)
5108 *	Description
5109 *		Read *size* bytes from user space address *user_ptr* in *tsk*'s
5110 *		address space, and stores the data in *dst*. *flags* is not
5111 *		used yet and is provided for future extensibility. This helper
5112 *		can only be used by sleepable programs.
5113 *	Return
5114 *		0 on success, or a negative error in case of failure. On error
5115 *		*dst* buffer is zeroed out.
5116 *
5117 * long bpf_skb_set_tstamp(struct sk_buff *skb, u64 tstamp, u32 tstamp_type)
5118 *	Description
5119 *		Change the __sk_buff->tstamp_type to *tstamp_type*
5120 *		and set *tstamp* to the __sk_buff->tstamp together.
5121 *
5122 *		If there is no need to change the __sk_buff->tstamp_type,
5123 *		the tstamp value can be directly written to __sk_buff->tstamp
5124 *		instead.
5125 *
5126 *		BPF_SKB_TSTAMP_DELIVERY_MONO is the only tstamp that
5127 *		will be kept during bpf_redirect_*().  A non zero
5128 *		*tstamp* must be used with the BPF_SKB_TSTAMP_DELIVERY_MONO
5129 *		*tstamp_type*.
5130 *
5131 *		A BPF_SKB_TSTAMP_UNSPEC *tstamp_type* can only be used
5132 *		with a zero *tstamp*.
5133 *
5134 *		Only IPv4 and IPv6 skb->protocol are supported.
5135 *
5136 *		This function is most useful when it needs to set a
5137 *		mono delivery time to __sk_buff->tstamp and then
5138 *		bpf_redirect_*() to the egress of an iface.  For example,
5139 *		changing the (rcv) timestamp in __sk_buff->tstamp at
5140 *		ingress to a mono delivery time and then bpf_redirect_*()
5141 *		to sch_fq@phy-dev.
5142 *	Return
5143 *		0 on success.
5144 *		**-EINVAL** for invalid input
5145 *		**-EOPNOTSUPP** for unsupported protocol
5146 *
5147 * long bpf_ima_file_hash(struct file *file, void *dst, u32 size)
5148 *	Description
5149 *		Returns a calculated IMA hash of the *file*.
5150 *		If the hash is larger than *size*, then only *size*
5151 *		bytes will be copied to *dst*
5152 *	Return
5153 *		The **hash_algo** is returned on success,
5154 *		**-EOPNOTSUP** if the hash calculation failed or **-EINVAL** if
5155 *		invalid arguments are passed.
5156 *
5157 * void *bpf_kptr_xchg(void *map_value, void *ptr)
5158 *	Description
5159 *		Exchange kptr at pointer *map_value* with *ptr*, and return the
5160 *		old value. *ptr* can be NULL, otherwise it must be a referenced
5161 *		pointer which will be released when this helper is called.
5162 *	Return
5163 *		The old value of kptr (which can be NULL). The returned pointer
5164 *		if not NULL, is a reference which must be released using its
5165 *		corresponding release function, or moved into a BPF map before
5166 *		program exit.
5167 *
5168 * void *bpf_map_lookup_percpu_elem(struct bpf_map *map, const void *key, u32 cpu)
5169 * 	Description
5170 * 		Perform a lookup in *percpu map* for an entry associated to
5171 * 		*key* on *cpu*.
5172 * 	Return
5173 * 		Map value associated to *key* on *cpu*, or **NULL** if no entry
5174 * 		was found or *cpu* is invalid.
5175 *
5176 * struct mptcp_sock *bpf_skc_to_mptcp_sock(void *sk)
5177 *	Description
5178 *		Dynamically cast a *sk* pointer to a *mptcp_sock* pointer.
5179 *	Return
5180 *		*sk* if casting is valid, or **NULL** otherwise.
5181 *
5182 * long bpf_dynptr_from_mem(void *data, u32 size, u64 flags, struct bpf_dynptr *ptr)
5183 *	Description
5184 *		Get a dynptr to local memory *data*.
5185 *
5186 *		*data* must be a ptr to a map value.
5187 *		The maximum *size* supported is DYNPTR_MAX_SIZE.
5188 *		*flags* is currently unused.
5189 *	Return
5190 *		0 on success, -E2BIG if the size exceeds DYNPTR_MAX_SIZE,
5191 *		-EINVAL if flags is not 0.
5192 *
5193 * long bpf_ringbuf_reserve_dynptr(void *ringbuf, u32 size, u64 flags, struct bpf_dynptr *ptr)
5194 *	Description
5195 *		Reserve *size* bytes of payload in a ring buffer *ringbuf*
5196 *		through the dynptr interface. *flags* must be 0.
5197 *
5198 *		Please note that a corresponding bpf_ringbuf_submit_dynptr or
5199 *		bpf_ringbuf_discard_dynptr must be called on *ptr*, even if the
5200 *		reservation fails. This is enforced by the verifier.
5201 *	Return
5202 *		0 on success, or a negative error in case of failure.
5203 *
5204 * void bpf_ringbuf_submit_dynptr(struct bpf_dynptr *ptr, u64 flags)
5205 *	Description
5206 *		Submit reserved ring buffer sample, pointed to by *data*,
5207 *		through the dynptr interface. This is a no-op if the dynptr is
5208 *		invalid/null.
5209 *
5210 *		For more information on *flags*, please see
5211 *		'bpf_ringbuf_submit'.
5212 *	Return
5213 *		Nothing. Always succeeds.
5214 *
5215 * void bpf_ringbuf_discard_dynptr(struct bpf_dynptr *ptr, u64 flags)
5216 *	Description
5217 *		Discard reserved ring buffer sample through the dynptr
5218 *		interface. This is a no-op if the dynptr is invalid/null.
5219 *
5220 *		For more information on *flags*, please see
5221 *		'bpf_ringbuf_discard'.
5222 *	Return
5223 *		Nothing. Always succeeds.
5224 *
5225 * long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset)
5226 *	Description
5227 *		Read *len* bytes from *src* into *dst*, starting from *offset*
5228 *		into *src*.
5229 *	Return
5230 *		0 on success, -E2BIG if *offset* + *len* exceeds the length
5231 *		of *src*'s data, -EINVAL if *src* is an invalid dynptr.
5232 *
5233 * long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len)
5234 *	Description
5235 *		Write *len* bytes from *src* into *dst*, starting from *offset*
5236 *		into *dst*.
5237 *	Return
5238 *		0 on success, -E2BIG if *offset* + *len* exceeds the length
5239 *		of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst*
5240 *		is a read-only dynptr.
5241 *
5242 * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len)
5243 *	Description
5244 *		Get a pointer to the underlying dynptr data.
5245 *
5246 *		*len* must be a statically known value. The returned data slice
5247 *		is invalidated whenever the dynptr is invalidated.
5248 *	Return
5249 *		Pointer to the underlying dynptr data, NULL if the dynptr is
5250 *		read-only, if the dynptr is invalid, or if the offset and length
5251 *		is out of bounds.
5252 */
5253#define __BPF_FUNC_MAPPER(FN)		\
5254	FN(unspec),			\
5255	FN(map_lookup_elem),		\
5256	FN(map_update_elem),		\
5257	FN(map_delete_elem),		\
5258	FN(probe_read),			\
5259	FN(ktime_get_ns),		\
5260	FN(trace_printk),		\
5261	FN(get_prandom_u32),		\
5262	FN(get_smp_processor_id),	\
5263	FN(skb_store_bytes),		\
5264	FN(l3_csum_replace),		\
5265	FN(l4_csum_replace),		\
5266	FN(tail_call),			\
5267	FN(clone_redirect),		\
5268	FN(get_current_pid_tgid),	\
5269	FN(get_current_uid_gid),	\
5270	FN(get_current_comm),		\
5271	FN(get_cgroup_classid),		\
5272	FN(skb_vlan_push),		\
5273	FN(skb_vlan_pop),		\
5274	FN(skb_get_tunnel_key),		\
5275	FN(skb_set_tunnel_key),		\
5276	FN(perf_event_read),		\
5277	FN(redirect),			\
5278	FN(get_route_realm),		\
5279	FN(perf_event_output),		\
5280	FN(skb_load_bytes),		\
5281	FN(get_stackid),		\
5282	FN(csum_diff),			\
5283	FN(skb_get_tunnel_opt),		\
5284	FN(skb_set_tunnel_opt),		\
5285	FN(skb_change_proto),		\
5286	FN(skb_change_type),		\
5287	FN(skb_under_cgroup),		\
5288	FN(get_hash_recalc),		\
5289	FN(get_current_task),		\
5290	FN(probe_write_user),		\
5291	FN(current_task_under_cgroup),	\
5292	FN(skb_change_tail),		\
5293	FN(skb_pull_data),		\
5294	FN(csum_update),		\
5295	FN(set_hash_invalid),		\
5296	FN(get_numa_node_id),		\
5297	FN(skb_change_head),		\
5298	FN(xdp_adjust_head),		\
5299	FN(probe_read_str),		\
5300	FN(get_socket_cookie),		\
5301	FN(get_socket_uid),		\
5302	FN(set_hash),			\
5303	FN(setsockopt),			\
5304	FN(skb_adjust_room),		\
5305	FN(redirect_map),		\
5306	FN(sk_redirect_map),		\
5307	FN(sock_map_update),		\
5308	FN(xdp_adjust_meta),		\
5309	FN(perf_event_read_value),	\
5310	FN(perf_prog_read_value),	\
5311	FN(getsockopt),			\
5312	FN(override_return),		\
5313	FN(sock_ops_cb_flags_set),	\
5314	FN(msg_redirect_map),		\
5315	FN(msg_apply_bytes),		\
5316	FN(msg_cork_bytes),		\
5317	FN(msg_pull_data),		\
5318	FN(bind),			\
5319	FN(xdp_adjust_tail),		\
5320	FN(skb_get_xfrm_state),		\
5321	FN(get_stack),			\
5322	FN(skb_load_bytes_relative),	\
5323	FN(fib_lookup),			\
5324	FN(sock_hash_update),		\
5325	FN(msg_redirect_hash),		\
5326	FN(sk_redirect_hash),		\
5327	FN(lwt_push_encap),		\
5328	FN(lwt_seg6_store_bytes),	\
5329	FN(lwt_seg6_adjust_srh),	\
5330	FN(lwt_seg6_action),		\
5331	FN(rc_repeat),			\
5332	FN(rc_keydown),			\
5333	FN(skb_cgroup_id),		\
5334	FN(get_current_cgroup_id),	\
5335	FN(get_local_storage),		\
5336	FN(sk_select_reuseport),	\
5337	FN(skb_ancestor_cgroup_id),	\
5338	FN(sk_lookup_tcp),		\
5339	FN(sk_lookup_udp),		\
5340	FN(sk_release),			\
5341	FN(map_push_elem),		\
5342	FN(map_pop_elem),		\
5343	FN(map_peek_elem),		\
5344	FN(msg_push_data),		\
5345	FN(msg_pop_data),		\
5346	FN(rc_pointer_rel),		\
5347	FN(spin_lock),			\
5348	FN(spin_unlock),		\
5349	FN(sk_fullsock),		\
5350	FN(tcp_sock),			\
5351	FN(skb_ecn_set_ce),		\
5352	FN(get_listener_sock),		\
5353	FN(skc_lookup_tcp),		\
5354	FN(tcp_check_syncookie),	\
5355	FN(sysctl_get_name),		\
5356	FN(sysctl_get_current_value),	\
5357	FN(sysctl_get_new_value),	\
5358	FN(sysctl_set_new_value),	\
5359	FN(strtol),			\
5360	FN(strtoul),			\
5361	FN(sk_storage_get),		\
5362	FN(sk_storage_delete),		\
5363	FN(send_signal),		\
5364	FN(tcp_gen_syncookie),		\
5365	FN(skb_output),			\
5366	FN(probe_read_user),		\
5367	FN(probe_read_kernel),		\
5368	FN(probe_read_user_str),	\
5369	FN(probe_read_kernel_str),	\
5370	FN(tcp_send_ack),		\
5371	FN(send_signal_thread),		\
5372	FN(jiffies64),			\
5373	FN(read_branch_records),	\
5374	FN(get_ns_current_pid_tgid),	\
5375	FN(xdp_output),			\
5376	FN(get_netns_cookie),		\
5377	FN(get_current_ancestor_cgroup_id),	\
5378	FN(sk_assign),			\
5379	FN(ktime_get_boot_ns),		\
5380	FN(seq_printf),			\
5381	FN(seq_write),			\
5382	FN(sk_cgroup_id),		\
5383	FN(sk_ancestor_cgroup_id),	\
5384	FN(ringbuf_output),		\
5385	FN(ringbuf_reserve),		\
5386	FN(ringbuf_submit),		\
5387	FN(ringbuf_discard),		\
5388	FN(ringbuf_query),		\
5389	FN(csum_level),			\
5390	FN(skc_to_tcp6_sock),		\
5391	FN(skc_to_tcp_sock),		\
5392	FN(skc_to_tcp_timewait_sock),	\
5393	FN(skc_to_tcp_request_sock),	\
5394	FN(skc_to_udp6_sock),		\
5395	FN(get_task_stack),		\
5396	FN(load_hdr_opt),		\
5397	FN(store_hdr_opt),		\
5398	FN(reserve_hdr_opt),		\
5399	FN(inode_storage_get),		\
5400	FN(inode_storage_delete),	\
5401	FN(d_path),			\
5402	FN(copy_from_user),		\
5403	FN(snprintf_btf),		\
5404	FN(seq_printf_btf),		\
5405	FN(skb_cgroup_classid),		\
5406	FN(redirect_neigh),		\
5407	FN(per_cpu_ptr),		\
5408	FN(this_cpu_ptr),		\
5409	FN(redirect_peer),		\
5410	FN(task_storage_get),		\
5411	FN(task_storage_delete),	\
5412	FN(get_current_task_btf),	\
5413	FN(bprm_opts_set),		\
5414	FN(ktime_get_coarse_ns),	\
5415	FN(ima_inode_hash),		\
5416	FN(sock_from_file),		\
5417	FN(check_mtu),			\
5418	FN(for_each_map_elem),		\
5419	FN(snprintf),			\
5420	FN(sys_bpf),			\
5421	FN(btf_find_by_name_kind),	\
5422	FN(sys_close),			\
5423	FN(timer_init),			\
5424	FN(timer_set_callback),		\
5425	FN(timer_start),		\
5426	FN(timer_cancel),		\
5427	FN(get_func_ip),		\
5428	FN(get_attach_cookie),		\
5429	FN(task_pt_regs),		\
5430	FN(get_branch_snapshot),	\
5431	FN(trace_vprintk),		\
5432	FN(skc_to_unix_sock),		\
5433	FN(kallsyms_lookup_name),	\
5434	FN(find_vma),			\
5435	FN(loop),			\
5436	FN(strncmp),			\
5437	FN(get_func_arg),		\
5438	FN(get_func_ret),		\
5439	FN(get_func_arg_cnt),		\
5440	FN(get_retval),			\
5441	FN(set_retval),			\
5442	FN(xdp_get_buff_len),		\
5443	FN(xdp_load_bytes),		\
5444	FN(xdp_store_bytes),		\
5445	FN(copy_from_user_task),	\
5446	FN(skb_set_tstamp),		\
5447	FN(ima_file_hash),		\
5448	FN(kptr_xchg),			\
5449	FN(map_lookup_percpu_elem),     \
5450	FN(skc_to_mptcp_sock),		\
5451	FN(dynptr_from_mem),		\
5452	FN(ringbuf_reserve_dynptr),	\
5453	FN(ringbuf_submit_dynptr),	\
5454	FN(ringbuf_discard_dynptr),	\
5455	FN(dynptr_read),		\
5456	FN(dynptr_write),		\
5457	FN(dynptr_data),		\
5458	/* */
5459
5460/* integer value in 'imm' field of BPF_CALL instruction selects which helper
5461 * function eBPF program intends to call
5462 */
5463#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5464enum bpf_func_id {
5465	__BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5466	__BPF_FUNC_MAX_ID,
5467};
5468#undef __BPF_ENUM_FN
5469
5470/* All flags used by eBPF helper functions, placed here. */
5471
5472/* BPF_FUNC_skb_store_bytes flags. */
5473enum {
5474	BPF_F_RECOMPUTE_CSUM		= (1ULL << 0),
5475	BPF_F_INVALIDATE_HASH		= (1ULL << 1),
5476};
5477
5478/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
5479 * First 4 bits are for passing the header field size.
5480 */
5481enum {
5482	BPF_F_HDR_FIELD_MASK		= 0xfULL,
5483};
5484
5485/* BPF_FUNC_l4_csum_replace flags. */
5486enum {
5487	BPF_F_PSEUDO_HDR		= (1ULL << 4),
5488	BPF_F_MARK_MANGLED_0		= (1ULL << 5),
5489	BPF_F_MARK_ENFORCE		= (1ULL << 6),
5490};
5491
5492/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
5493enum {
5494	BPF_F_INGRESS			= (1ULL << 0),
5495};
5496
5497/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
5498enum {
5499	BPF_F_TUNINFO_IPV6		= (1ULL << 0),
5500};
5501
5502/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
5503enum {
5504	BPF_F_SKIP_FIELD_MASK		= 0xffULL,
5505	BPF_F_USER_STACK		= (1ULL << 8),
5506/* flags used by BPF_FUNC_get_stackid only. */
5507	BPF_F_FAST_STACK_CMP		= (1ULL << 9),
5508	BPF_F_REUSE_STACKID		= (1ULL << 10),
5509/* flags used by BPF_FUNC_get_stack only. */
5510	BPF_F_USER_BUILD_ID		= (1ULL << 11),
5511};
5512
5513/* BPF_FUNC_skb_set_tunnel_key flags. */
5514enum {
5515	BPF_F_ZERO_CSUM_TX		= (1ULL << 1),
5516	BPF_F_DONT_FRAGMENT		= (1ULL << 2),
5517	BPF_F_SEQ_NUMBER		= (1ULL << 3),
5518};
5519
5520/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
5521 * BPF_FUNC_perf_event_read_value flags.
5522 */
5523enum {
5524	BPF_F_INDEX_MASK		= 0xffffffffULL,
5525	BPF_F_CURRENT_CPU		= BPF_F_INDEX_MASK,
5526/* BPF_FUNC_perf_event_output for sk_buff input context. */
5527	BPF_F_CTXLEN_MASK		= (0xfffffULL << 32),
5528};
5529
5530/* Current network namespace */
5531enum {
5532	BPF_F_CURRENT_NETNS		= (-1L),
5533};
5534
5535/* BPF_FUNC_csum_level level values. */
5536enum {
5537	BPF_CSUM_LEVEL_QUERY,
5538	BPF_CSUM_LEVEL_INC,
5539	BPF_CSUM_LEVEL_DEC,
5540	BPF_CSUM_LEVEL_RESET,
5541};
5542
5543/* BPF_FUNC_skb_adjust_room flags. */
5544enum {
5545	BPF_F_ADJ_ROOM_FIXED_GSO	= (1ULL << 0),
5546	BPF_F_ADJ_ROOM_ENCAP_L3_IPV4	= (1ULL << 1),
5547	BPF_F_ADJ_ROOM_ENCAP_L3_IPV6	= (1ULL << 2),
5548	BPF_F_ADJ_ROOM_ENCAP_L4_GRE	= (1ULL << 3),
5549	BPF_F_ADJ_ROOM_ENCAP_L4_UDP	= (1ULL << 4),
5550	BPF_F_ADJ_ROOM_NO_CSUM_RESET	= (1ULL << 5),
5551	BPF_F_ADJ_ROOM_ENCAP_L2_ETH	= (1ULL << 6),
5552};
5553
5554enum {
5555	BPF_ADJ_ROOM_ENCAP_L2_MASK	= 0xff,
5556	BPF_ADJ_ROOM_ENCAP_L2_SHIFT	= 56,
5557};
5558
5559#define BPF_F_ADJ_ROOM_ENCAP_L2(len)	(((__u64)len & \
5560					  BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5561					 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5562
5563/* BPF_FUNC_sysctl_get_name flags. */
5564enum {
5565	BPF_F_SYSCTL_BASE_NAME		= (1ULL << 0),
5566};
5567
5568/* BPF_FUNC_<kernel_obj>_storage_get flags */
5569enum {
5570	BPF_LOCAL_STORAGE_GET_F_CREATE	= (1ULL << 0),
5571	/* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
5572	 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5573	 */
5574	BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
5575};
5576
5577/* BPF_FUNC_read_branch_records flags. */
5578enum {
5579	BPF_F_GET_BRANCH_RECORDS_SIZE	= (1ULL << 0),
5580};
5581
5582/* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
5583 * BPF_FUNC_bpf_ringbuf_output flags.
5584 */
5585enum {
5586	BPF_RB_NO_WAKEUP		= (1ULL << 0),
5587	BPF_RB_FORCE_WAKEUP		= (1ULL << 1),
5588};
5589
5590/* BPF_FUNC_bpf_ringbuf_query flags */
5591enum {
5592	BPF_RB_AVAIL_DATA = 0,
5593	BPF_RB_RING_SIZE = 1,
5594	BPF_RB_CONS_POS = 2,
5595	BPF_RB_PROD_POS = 3,
5596};
5597
5598/* BPF ring buffer constants */
5599enum {
5600	BPF_RINGBUF_BUSY_BIT		= (1U << 31),
5601	BPF_RINGBUF_DISCARD_BIT		= (1U << 30),
5602	BPF_RINGBUF_HDR_SZ		= 8,
5603};
5604
5605/* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
5606enum {
5607	BPF_SK_LOOKUP_F_REPLACE		= (1ULL << 0),
5608	BPF_SK_LOOKUP_F_NO_REUSEPORT	= (1ULL << 1),
5609};
5610
5611/* Mode for BPF_FUNC_skb_adjust_room helper. */
5612enum bpf_adj_room_mode {
5613	BPF_ADJ_ROOM_NET,
5614	BPF_ADJ_ROOM_MAC,
5615};
5616
5617/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
5618enum bpf_hdr_start_off {
5619	BPF_HDR_START_MAC,
5620	BPF_HDR_START_NET,
5621};
5622
5623/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
5624enum bpf_lwt_encap_mode {
5625	BPF_LWT_ENCAP_SEG6,
5626	BPF_LWT_ENCAP_SEG6_INLINE,
5627	BPF_LWT_ENCAP_IP,
5628};
5629
5630/* Flags for bpf_bprm_opts_set helper */
5631enum {
5632	BPF_F_BPRM_SECUREEXEC	= (1ULL << 0),
5633};
5634
5635/* Flags for bpf_redirect_map helper */
5636enum {
5637	BPF_F_BROADCAST		= (1ULL << 3),
5638	BPF_F_EXCLUDE_INGRESS	= (1ULL << 4),
5639};
5640
5641#define __bpf_md_ptr(type, name)	\
5642union {					\
5643	type name;			\
5644	__u64 :64;			\
5645} __attribute__((aligned(8)))
5646
5647enum {
5648	BPF_SKB_TSTAMP_UNSPEC,
5649	BPF_SKB_TSTAMP_DELIVERY_MONO,	/* tstamp has mono delivery time */
5650	/* For any BPF_SKB_TSTAMP_* that the bpf prog cannot handle,
5651	 * the bpf prog should handle it like BPF_SKB_TSTAMP_UNSPEC
5652	 * and try to deduce it by ingress, egress or skb->sk->sk_clockid.
5653	 */
5654};
5655
5656/* user accessible mirror of in-kernel sk_buff.
5657 * new fields can only be added to the end of this structure
5658 */
5659struct __sk_buff {
5660	__u32 len;
5661	__u32 pkt_type;
5662	__u32 mark;
5663	__u32 queue_mapping;
5664	__u32 protocol;
5665	__u32 vlan_present;
5666	__u32 vlan_tci;
5667	__u32 vlan_proto;
5668	__u32 priority;
5669	__u32 ingress_ifindex;
5670	__u32 ifindex;
5671	__u32 tc_index;
5672	__u32 cb[5];
5673	__u32 hash;
5674	__u32 tc_classid;
5675	__u32 data;
5676	__u32 data_end;
5677	__u32 napi_id;
5678
5679	/* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
5680	__u32 family;
5681	__u32 remote_ip4;	/* Stored in network byte order */
5682	__u32 local_ip4;	/* Stored in network byte order */
5683	__u32 remote_ip6[4];	/* Stored in network byte order */
5684	__u32 local_ip6[4];	/* Stored in network byte order */
5685	__u32 remote_port;	/* Stored in network byte order */
5686	__u32 local_port;	/* stored in host byte order */
5687	/* ... here. */
5688
5689	__u32 data_meta;
5690	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5691	__u64 tstamp;
5692	__u32 wire_len;
5693	__u32 gso_segs;
5694	__bpf_md_ptr(struct bpf_sock *, sk);
5695	__u32 gso_size;
5696	__u8  tstamp_type;
5697	__u32 :24;		/* Padding, future use. */
5698	__u64 hwtstamp;
5699};
5700
5701struct bpf_tunnel_key {
5702	__u32 tunnel_id;
5703	union {
5704		__u32 remote_ipv4;
5705		__u32 remote_ipv6[4];
5706	};
5707	__u8 tunnel_tos;
5708	__u8 tunnel_ttl;
5709	__u16 tunnel_ext;	/* Padding, future use. */
5710	__u32 tunnel_label;
5711	union {
5712		__u32 local_ipv4;
5713		__u32 local_ipv6[4];
5714	};
5715};
5716
5717/* user accessible mirror of in-kernel xfrm_state.
5718 * new fields can only be added to the end of this structure
5719 */
5720struct bpf_xfrm_state {
5721	__u32 reqid;
5722	__u32 spi;	/* Stored in network byte order */
5723	__u16 family;
5724	__u16 ext;	/* Padding, future use. */
5725	union {
5726		__u32 remote_ipv4;	/* Stored in network byte order */
5727		__u32 remote_ipv6[4];	/* Stored in network byte order */
5728	};
5729};
5730
5731/* Generic BPF return codes which all BPF program types may support.
5732 * The values are binary compatible with their TC_ACT_* counter-part to
5733 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5734 * programs.
5735 *
5736 * XDP is handled seprately, see XDP_*.
5737 */
5738enum bpf_ret_code {
5739	BPF_OK = 0,
5740	/* 1 reserved */
5741	BPF_DROP = 2,
5742	/* 3-6 reserved */
5743	BPF_REDIRECT = 7,
5744	/* >127 are reserved for prog type specific return codes.
5745	 *
5746	 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5747	 *    BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5748	 *    changed and should be routed based on its new L3 header.
5749	 *    (This is an L3 redirect, as opposed to L2 redirect
5750	 *    represented by BPF_REDIRECT above).
5751	 */
5752	BPF_LWT_REROUTE = 128,
5753};
5754
5755struct bpf_sock {
5756	__u32 bound_dev_if;
5757	__u32 family;
5758	__u32 type;
5759	__u32 protocol;
5760	__u32 mark;
5761	__u32 priority;
5762	/* IP address also allows 1 and 2 bytes access */
5763	__u32 src_ip4;
5764	__u32 src_ip6[4];
5765	__u32 src_port;		/* host byte order */
5766	__be16 dst_port;	/* network byte order */
5767	__u16 :16;		/* zero padding */
5768	__u32 dst_ip4;
5769	__u32 dst_ip6[4];
5770	__u32 state;
5771	__s32 rx_queue_mapping;
5772};
5773
5774struct bpf_tcp_sock {
5775	__u32 snd_cwnd;		/* Sending congestion window		*/
5776	__u32 srtt_us;		/* smoothed round trip time << 3 in usecs */
5777	__u32 rtt_min;
5778	__u32 snd_ssthresh;	/* Slow start size threshold		*/
5779	__u32 rcv_nxt;		/* What we want to receive next		*/
5780	__u32 snd_nxt;		/* Next sequence we send		*/
5781	__u32 snd_una;		/* First byte we want an ack for	*/
5782	__u32 mss_cache;	/* Cached effective mss, not including SACKS */
5783	__u32 ecn_flags;	/* ECN status bits.			*/
5784	__u32 rate_delivered;	/* saved rate sample: packets delivered */
5785	__u32 rate_interval_us;	/* saved rate sample: time elapsed */
5786	__u32 packets_out;	/* Packets which are "in flight"	*/
5787	__u32 retrans_out;	/* Retransmitted packets out		*/
5788	__u32 total_retrans;	/* Total retransmits for entire connection */
5789	__u32 segs_in;		/* RFC4898 tcpEStatsPerfSegsIn
5790				 * total number of segments in.
5791				 */
5792	__u32 data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
5793				 * total number of data segments in.
5794				 */
5795	__u32 segs_out;		/* RFC4898 tcpEStatsPerfSegsOut
5796				 * The total number of segments sent.
5797				 */
5798	__u32 data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
5799				 * total number of data segments sent.
5800				 */
5801	__u32 lost_out;		/* Lost packets			*/
5802	__u32 sacked_out;	/* SACK'd packets			*/
5803	__u64 bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
5804				 * sum(delta(rcv_nxt)), or how many bytes
5805				 * were acked.
5806				 */
5807	__u64 bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
5808				 * sum(delta(snd_una)), or how many bytes
5809				 * were acked.
5810				 */
5811	__u32 dsack_dups;	/* RFC4898 tcpEStatsStackDSACKDups
5812				 * total number of DSACK blocks received
5813				 */
5814	__u32 delivered;	/* Total data packets delivered incl. rexmits */
5815	__u32 delivered_ce;	/* Like the above but only ECE marked packets */
5816	__u32 icsk_retransmits;	/* Number of unrecovered [RTO] timeouts */
5817};
5818
5819struct bpf_sock_tuple {
5820	union {
5821		struct {
5822			__be32 saddr;
5823			__be32 daddr;
5824			__be16 sport;
5825			__be16 dport;
5826		} ipv4;
5827		struct {
5828			__be32 saddr[4];
5829			__be32 daddr[4];
5830			__be16 sport;
5831			__be16 dport;
5832		} ipv6;
5833	};
5834};
5835
5836struct bpf_xdp_sock {
5837	__u32 queue_id;
5838};
5839
5840#define XDP_PACKET_HEADROOM 256
5841
5842/* User return codes for XDP prog type.
5843 * A valid XDP program must return one of these defined values. All other
5844 * return codes are reserved for future use. Unknown return codes will
5845 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
5846 */
5847enum xdp_action {
5848	XDP_ABORTED = 0,
5849	XDP_DROP,
5850	XDP_PASS,
5851	XDP_TX,
5852	XDP_REDIRECT,
5853};
5854
5855/* user accessible metadata for XDP packet hook
5856 * new fields must be added to the end of this structure
5857 */
5858struct xdp_md {
5859	__u32 data;
5860	__u32 data_end;
5861	__u32 data_meta;
5862	/* Below access go through struct xdp_rxq_info */
5863	__u32 ingress_ifindex; /* rxq->dev->ifindex */
5864	__u32 rx_queue_index;  /* rxq->queue_index  */
5865
5866	__u32 egress_ifindex;  /* txq->dev->ifindex */
5867};
5868
5869/* DEVMAP map-value layout
5870 *
5871 * The struct data-layout of map-value is a configuration interface.
5872 * New members can only be added to the end of this structure.
5873 */
5874struct bpf_devmap_val {
5875	__u32 ifindex;   /* device index */
5876	union {
5877		int   fd;  /* prog fd on map write */
5878		__u32 id;  /* prog id on map read */
5879	} bpf_prog;
5880};
5881
5882/* CPUMAP map-value layout
5883 *
5884 * The struct data-layout of map-value is a configuration interface.
5885 * New members can only be added to the end of this structure.
5886 */
5887struct bpf_cpumap_val {
5888	__u32 qsize;	/* queue size to remote target CPU */
5889	union {
5890		int   fd;	/* prog fd on map write */
5891		__u32 id;	/* prog id on map read */
5892	} bpf_prog;
5893};
5894
5895enum sk_action {
5896	SK_DROP = 0,
5897	SK_PASS,
5898};
5899
5900/* user accessible metadata for SK_MSG packet hook, new fields must
5901 * be added to the end of this structure
5902 */
5903struct sk_msg_md {
5904	__bpf_md_ptr(void *, data);
5905	__bpf_md_ptr(void *, data_end);
5906
5907	__u32 family;
5908	__u32 remote_ip4;	/* Stored in network byte order */
5909	__u32 local_ip4;	/* Stored in network byte order */
5910	__u32 remote_ip6[4];	/* Stored in network byte order */
5911	__u32 local_ip6[4];	/* Stored in network byte order */
5912	__u32 remote_port;	/* Stored in network byte order */
5913	__u32 local_port;	/* stored in host byte order */
5914	__u32 size;		/* Total size of sk_msg */
5915
5916	__bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
5917};
5918
5919struct sk_reuseport_md {
5920	/*
5921	 * Start of directly accessible data. It begins from
5922	 * the tcp/udp header.
5923	 */
5924	__bpf_md_ptr(void *, data);
5925	/* End of directly accessible data */
5926	__bpf_md_ptr(void *, data_end);
5927	/*
5928	 * Total length of packet (starting from the tcp/udp header).
5929	 * Note that the directly accessible bytes (data_end - data)
5930	 * could be less than this "len".  Those bytes could be
5931	 * indirectly read by a helper "bpf_skb_load_bytes()".
5932	 */
5933	__u32 len;
5934	/*
5935	 * Eth protocol in the mac header (network byte order). e.g.
5936	 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
5937	 */
5938	__u32 eth_protocol;
5939	__u32 ip_protocol;	/* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
5940	__u32 bind_inany;	/* Is sock bound to an INANY address? */
5941	__u32 hash;		/* A hash of the packet 4 tuples */
5942	/* When reuse->migrating_sk is NULL, it is selecting a sk for the
5943	 * new incoming connection request (e.g. selecting a listen sk for
5944	 * the received SYN in the TCP case).  reuse->sk is one of the sk
5945	 * in the reuseport group. The bpf prog can use reuse->sk to learn
5946	 * the local listening ip/port without looking into the skb.
5947	 *
5948	 * When reuse->migrating_sk is not NULL, reuse->sk is closed and
5949	 * reuse->migrating_sk is the socket that needs to be migrated
5950	 * to another listening socket.  migrating_sk could be a fullsock
5951	 * sk that is fully established or a reqsk that is in-the-middle
5952	 * of 3-way handshake.
5953	 */
5954	__bpf_md_ptr(struct bpf_sock *, sk);
5955	__bpf_md_ptr(struct bpf_sock *, migrating_sk);
5956};
5957
5958#define BPF_TAG_SIZE	8
5959
5960struct bpf_prog_info {
5961	__u32 type;
5962	__u32 id;
5963	__u8  tag[BPF_TAG_SIZE];
5964	__u32 jited_prog_len;
5965	__u32 xlated_prog_len;
5966	__aligned_u64 jited_prog_insns;
5967	__aligned_u64 xlated_prog_insns;
5968	__u64 load_time;	/* ns since boottime */
5969	__u32 created_by_uid;
5970	__u32 nr_map_ids;
5971	__aligned_u64 map_ids;
5972	char name[BPF_OBJ_NAME_LEN];
5973	__u32 ifindex;
5974	__u32 gpl_compatible:1;
5975	__u32 :31; /* alignment pad */
5976	__u64 netns_dev;
5977	__u64 netns_ino;
5978	__u32 nr_jited_ksyms;
5979	__u32 nr_jited_func_lens;
5980	__aligned_u64 jited_ksyms;
5981	__aligned_u64 jited_func_lens;
5982	__u32 btf_id;
5983	__u32 func_info_rec_size;
5984	__aligned_u64 func_info;
5985	__u32 nr_func_info;
5986	__u32 nr_line_info;
5987	__aligned_u64 line_info;
5988	__aligned_u64 jited_line_info;
5989	__u32 nr_jited_line_info;
5990	__u32 line_info_rec_size;
5991	__u32 jited_line_info_rec_size;
5992	__u32 nr_prog_tags;
5993	__aligned_u64 prog_tags;
5994	__u64 run_time_ns;
5995	__u64 run_cnt;
5996	__u64 recursion_misses;
5997	__u32 verified_insns;
5998} __attribute__((aligned(8)));
5999
6000struct bpf_map_info {
6001	__u32 type;
6002	__u32 id;
6003	__u32 key_size;
6004	__u32 value_size;
6005	__u32 max_entries;
6006	__u32 map_flags;
6007	char  name[BPF_OBJ_NAME_LEN];
6008	__u32 ifindex;
6009	__u32 btf_vmlinux_value_type_id;
6010	__u64 netns_dev;
6011	__u64 netns_ino;
6012	__u32 btf_id;
6013	__u32 btf_key_type_id;
6014	__u32 btf_value_type_id;
6015	__u32 :32;	/* alignment pad */
6016	__u64 map_extra;
6017} __attribute__((aligned(8)));
6018
6019struct bpf_btf_info {
6020	__aligned_u64 btf;
6021	__u32 btf_size;
6022	__u32 id;
6023	__aligned_u64 name;
6024	__u32 name_len;
6025	__u32 kernel_btf;
6026} __attribute__((aligned(8)));
6027
6028struct bpf_link_info {
6029	__u32 type;
6030	__u32 id;
6031	__u32 prog_id;
6032	union {
6033		struct {
6034			__aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
6035			__u32 tp_name_len;     /* in/out: tp_name buffer len */
6036		} raw_tracepoint;
6037		struct {
6038			__u32 attach_type;
6039			__u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */
6040			__u32 target_btf_id; /* BTF type id inside the object */
6041		} tracing;
6042		struct {
6043			__u64 cgroup_id;
6044			__u32 attach_type;
6045		} cgroup;
6046		struct {
6047			__aligned_u64 target_name; /* in/out: target_name buffer ptr */
6048			__u32 target_name_len;	   /* in/out: target_name buffer len */
6049			union {
6050				struct {
6051					__u32 map_id;
6052				} map;
6053			};
6054		} iter;
6055		struct  {
6056			__u32 netns_ino;
6057			__u32 attach_type;
6058		} netns;
6059		struct {
6060			__u32 ifindex;
6061		} xdp;
6062	};
6063} __attribute__((aligned(8)));
6064
6065/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
6066 * by user and intended to be used by socket (e.g. to bind to, depends on
6067 * attach type).
6068 */
6069struct bpf_sock_addr {
6070	__u32 user_family;	/* Allows 4-byte read, but no write. */
6071	__u32 user_ip4;		/* Allows 1,2,4-byte read and 4-byte write.
6072				 * Stored in network byte order.
6073				 */
6074	__u32 user_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
6075				 * Stored in network byte order.
6076				 */
6077	__u32 user_port;	/* Allows 1,2,4-byte read and 4-byte write.
6078				 * Stored in network byte order
6079				 */
6080	__u32 family;		/* Allows 4-byte read, but no write */
6081	__u32 type;		/* Allows 4-byte read, but no write */
6082	__u32 protocol;		/* Allows 4-byte read, but no write */
6083	__u32 msg_src_ip4;	/* Allows 1,2,4-byte read and 4-byte write.
6084				 * Stored in network byte order.
6085				 */
6086	__u32 msg_src_ip6[4];	/* Allows 1,2,4,8-byte read and 4,8-byte write.
6087				 * Stored in network byte order.
6088				 */
6089	__bpf_md_ptr(struct bpf_sock *, sk);
6090};
6091
6092/* User bpf_sock_ops struct to access socket values and specify request ops
6093 * and their replies.
6094 * Some of this fields are in network (bigendian) byte order and may need
6095 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
6096 * New fields can only be added at the end of this structure
6097 */
6098struct bpf_sock_ops {
6099	__u32 op;
6100	union {
6101		__u32 args[4];		/* Optionally passed to bpf program */
6102		__u32 reply;		/* Returned by bpf program	    */
6103		__u32 replylong[4];	/* Optionally returned by bpf prog  */
6104	};
6105	__u32 family;
6106	__u32 remote_ip4;	/* Stored in network byte order */
6107	__u32 local_ip4;	/* Stored in network byte order */
6108	__u32 remote_ip6[4];	/* Stored in network byte order */
6109	__u32 local_ip6[4];	/* Stored in network byte order */
6110	__u32 remote_port;	/* Stored in network byte order */
6111	__u32 local_port;	/* stored in host byte order */
6112	__u32 is_fullsock;	/* Some TCP fields are only valid if
6113				 * there is a full socket. If not, the
6114				 * fields read as zero.
6115				 */
6116	__u32 snd_cwnd;
6117	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
6118	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
6119	__u32 state;
6120	__u32 rtt_min;
6121	__u32 snd_ssthresh;
6122	__u32 rcv_nxt;
6123	__u32 snd_nxt;
6124	__u32 snd_una;
6125	__u32 mss_cache;
6126	__u32 ecn_flags;
6127	__u32 rate_delivered;
6128	__u32 rate_interval_us;
6129	__u32 packets_out;
6130	__u32 retrans_out;
6131	__u32 total_retrans;
6132	__u32 segs_in;
6133	__u32 data_segs_in;
6134	__u32 segs_out;
6135	__u32 data_segs_out;
6136	__u32 lost_out;
6137	__u32 sacked_out;
6138	__u32 sk_txhash;
6139	__u64 bytes_received;
6140	__u64 bytes_acked;
6141	__bpf_md_ptr(struct bpf_sock *, sk);
6142	/* [skb_data, skb_data_end) covers the whole TCP header.
6143	 *
6144	 * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
6145	 * BPF_SOCK_OPS_HDR_OPT_LEN_CB:   Not useful because the
6146	 *                                header has not been written.
6147	 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
6148	 *				  been written so far.
6149	 * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:  The SYNACK that concludes
6150	 *					the 3WHS.
6151	 * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
6152	 *					the 3WHS.
6153	 *
6154	 * bpf_load_hdr_opt() can also be used to read a particular option.
6155	 */
6156	__bpf_md_ptr(void *, skb_data);
6157	__bpf_md_ptr(void *, skb_data_end);
6158	__u32 skb_len;		/* The total length of a packet.
6159				 * It includes the header, options,
6160				 * and payload.
6161				 */
6162	__u32 skb_tcp_flags;	/* tcp_flags of the header.  It provides
6163				 * an easy way to check for tcp_flags
6164				 * without parsing skb_data.
6165				 *
6166				 * In particular, the skb_tcp_flags
6167				 * will still be available in
6168				 * BPF_SOCK_OPS_HDR_OPT_LEN even though
6169				 * the outgoing header has not
6170				 * been written yet.
6171				 */
6172};
6173
6174/* Definitions for bpf_sock_ops_cb_flags */
6175enum {
6176	BPF_SOCK_OPS_RTO_CB_FLAG	= (1<<0),
6177	BPF_SOCK_OPS_RETRANS_CB_FLAG	= (1<<1),
6178	BPF_SOCK_OPS_STATE_CB_FLAG	= (1<<2),
6179	BPF_SOCK_OPS_RTT_CB_FLAG	= (1<<3),
6180	/* Call bpf for all received TCP headers.  The bpf prog will be
6181	 * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6182	 *
6183	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6184	 * for the header option related helpers that will be useful
6185	 * to the bpf programs.
6186	 *
6187	 * It could be used at the client/active side (i.e. connect() side)
6188	 * when the server told it that the server was in syncookie
6189	 * mode and required the active side to resend the bpf-written
6190	 * options.  The active side can keep writing the bpf-options until
6191	 * it received a valid packet from the server side to confirm
6192	 * the earlier packet (and options) has been received.  The later
6193	 * example patch is using it like this at the active side when the
6194	 * server is in syncookie mode.
6195	 *
6196	 * The bpf prog will usually turn this off in the common cases.
6197	 */
6198	BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG	= (1<<4),
6199	/* Call bpf when kernel has received a header option that
6200	 * the kernel cannot handle.  The bpf prog will be called under
6201	 * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
6202	 *
6203	 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
6204	 * for the header option related helpers that will be useful
6205	 * to the bpf programs.
6206	 */
6207	BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
6208	/* Call bpf when the kernel is writing header options for the
6209	 * outgoing packet.  The bpf prog will first be called
6210	 * to reserve space in a skb under
6211	 * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB.  Then
6212	 * the bpf prog will be called to write the header option(s)
6213	 * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6214	 *
6215	 * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
6216	 * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
6217	 * related helpers that will be useful to the bpf programs.
6218	 *
6219	 * The kernel gets its chance to reserve space and write
6220	 * options first before the BPF program does.
6221	 */
6222	BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
6223/* Mask of all currently supported cb flags */
6224	BPF_SOCK_OPS_ALL_CB_FLAGS       = 0x7F,
6225};
6226
6227/* List of known BPF sock_ops operators.
6228 * New entries can only be added at the end
6229 */
6230enum {
6231	BPF_SOCK_OPS_VOID,
6232	BPF_SOCK_OPS_TIMEOUT_INIT,	/* Should return SYN-RTO value to use or
6233					 * -1 if default value should be used
6234					 */
6235	BPF_SOCK_OPS_RWND_INIT,		/* Should return initial advertized
6236					 * window (in packets) or -1 if default
6237					 * value should be used
6238					 */
6239	BPF_SOCK_OPS_TCP_CONNECT_CB,	/* Calls BPF program right before an
6240					 * active connection is initialized
6241					 */
6242	BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB,	/* Calls BPF program when an
6243						 * active connection is
6244						 * established
6245						 */
6246	BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB,	/* Calls BPF program when a
6247						 * passive connection is
6248						 * established
6249						 */
6250	BPF_SOCK_OPS_NEEDS_ECN,		/* If connection's congestion control
6251					 * needs ECN
6252					 */
6253	BPF_SOCK_OPS_BASE_RTT,		/* Get base RTT. The correct value is
6254					 * based on the path and may be
6255					 * dependent on the congestion control
6256					 * algorithm. In general it indicates
6257					 * a congestion threshold. RTTs above
6258					 * this indicate congestion
6259					 */
6260	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
6261					 * Arg1: value of icsk_retransmits
6262					 * Arg2: value of icsk_rto
6263					 * Arg3: whether RTO has expired
6264					 */
6265	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
6266					 * Arg1: sequence number of 1st byte
6267					 * Arg2: # segments
6268					 * Arg3: return value of
6269					 *       tcp_transmit_skb (0 => success)
6270					 */
6271	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
6272					 * Arg1: old_state
6273					 * Arg2: new_state
6274					 */
6275	BPF_SOCK_OPS_TCP_LISTEN_CB,	/* Called on listen(2), right after
6276					 * socket transition to LISTEN state.
6277					 */
6278	BPF_SOCK_OPS_RTT_CB,		/* Called on every RTT.
6279					 */
6280	BPF_SOCK_OPS_PARSE_HDR_OPT_CB,	/* Parse the header option.
6281					 * It will be called to handle
6282					 * the packets received at
6283					 * an already established
6284					 * connection.
6285					 *
6286					 * sock_ops->skb_data:
6287					 * Referring to the received skb.
6288					 * It covers the TCP header only.
6289					 *
6290					 * bpf_load_hdr_opt() can also
6291					 * be used to search for a
6292					 * particular option.
6293					 */
6294	BPF_SOCK_OPS_HDR_OPT_LEN_CB,	/* Reserve space for writing the
6295					 * header option later in
6296					 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6297					 * Arg1: bool want_cookie. (in
6298					 *       writing SYNACK only)
6299					 *
6300					 * sock_ops->skb_data:
6301					 * Not available because no header has
6302					 * been	written yet.
6303					 *
6304					 * sock_ops->skb_tcp_flags:
6305					 * The tcp_flags of the
6306					 * outgoing skb. (e.g. SYN, ACK, FIN).
6307					 *
6308					 * bpf_reserve_hdr_opt() should
6309					 * be used to reserve space.
6310					 */
6311	BPF_SOCK_OPS_WRITE_HDR_OPT_CB,	/* Write the header options
6312					 * Arg1: bool want_cookie. (in
6313					 *       writing SYNACK only)
6314					 *
6315					 * sock_ops->skb_data:
6316					 * Referring to the outgoing skb.
6317					 * It covers the TCP header
6318					 * that has already been written
6319					 * by the kernel and the
6320					 * earlier bpf-progs.
6321					 *
6322					 * sock_ops->skb_tcp_flags:
6323					 * The tcp_flags of the outgoing
6324					 * skb. (e.g. SYN, ACK, FIN).
6325					 *
6326					 * bpf_store_hdr_opt() should
6327					 * be used to write the
6328					 * option.
6329					 *
6330					 * bpf_load_hdr_opt() can also
6331					 * be used to search for a
6332					 * particular option that
6333					 * has already been written
6334					 * by the kernel or the
6335					 * earlier bpf-progs.
6336					 */
6337};
6338
6339/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
6340 * changes between the TCP and BPF versions. Ideally this should never happen.
6341 * If it does, we need to add code to convert them before calling
6342 * the BPF sock_ops function.
6343 */
6344enum {
6345	BPF_TCP_ESTABLISHED = 1,
6346	BPF_TCP_SYN_SENT,
6347	BPF_TCP_SYN_RECV,
6348	BPF_TCP_FIN_WAIT1,
6349	BPF_TCP_FIN_WAIT2,
6350	BPF_TCP_TIME_WAIT,
6351	BPF_TCP_CLOSE,
6352	BPF_TCP_CLOSE_WAIT,
6353	BPF_TCP_LAST_ACK,
6354	BPF_TCP_LISTEN,
6355	BPF_TCP_CLOSING,	/* Now a valid state */
6356	BPF_TCP_NEW_SYN_RECV,
6357
6358	BPF_TCP_MAX_STATES	/* Leave at the end! */
6359};
6360
6361enum {
6362	TCP_BPF_IW		= 1001,	/* Set TCP initial congestion window */
6363	TCP_BPF_SNDCWND_CLAMP	= 1002,	/* Set sndcwnd_clamp */
6364	TCP_BPF_DELACK_MAX	= 1003, /* Max delay ack in usecs */
6365	TCP_BPF_RTO_MIN		= 1004, /* Min delay ack in usecs */
6366	/* Copy the SYN pkt to optval
6367	 *
6368	 * BPF_PROG_TYPE_SOCK_OPS only.  It is similar to the
6369	 * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
6370	 * to only getting from the saved_syn.  It can either get the
6371	 * syn packet from:
6372	 *
6373	 * 1. the just-received SYN packet (only available when writing the
6374	 *    SYNACK).  It will be useful when it is not necessary to
6375	 *    save the SYN packet for latter use.  It is also the only way
6376	 *    to get the SYN during syncookie mode because the syn
6377	 *    packet cannot be saved during syncookie.
6378	 *
6379	 * OR
6380	 *
6381	 * 2. the earlier saved syn which was done by
6382	 *    bpf_setsockopt(TCP_SAVE_SYN).
6383	 *
6384	 * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
6385	 * SYN packet is obtained.
6386	 *
6387	 * If the bpf-prog does not need the IP[46] header,  the
6388	 * bpf-prog can avoid parsing the IP header by using
6389	 * TCP_BPF_SYN.  Otherwise, the bpf-prog can get both
6390	 * IP[46] and TCP header by using TCP_BPF_SYN_IP.
6391	 *
6392	 *      >0: Total number of bytes copied
6393	 * -ENOSPC: Not enough space in optval. Only optlen number of
6394	 *          bytes is copied.
6395	 * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
6396	 *	    is not saved by setsockopt(TCP_SAVE_SYN).
6397	 */
6398	TCP_BPF_SYN		= 1005, /* Copy the TCP header */
6399	TCP_BPF_SYN_IP		= 1006, /* Copy the IP[46] and TCP header */
6400	TCP_BPF_SYN_MAC         = 1007, /* Copy the MAC, IP[46], and TCP header */
6401};
6402
6403enum {
6404	BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
6405};
6406
6407/* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
6408 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6409 */
6410enum {
6411	BPF_WRITE_HDR_TCP_CURRENT_MSS = 1,	/* Kernel is finding the
6412						 * total option spaces
6413						 * required for an established
6414						 * sk in order to calculate the
6415						 * MSS.  No skb is actually
6416						 * sent.
6417						 */
6418	BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2,	/* Kernel is in syncookie mode
6419						 * when sending a SYN.
6420						 */
6421};
6422
6423struct bpf_perf_event_value {
6424	__u64 counter;
6425	__u64 enabled;
6426	__u64 running;
6427};
6428
6429enum {
6430	BPF_DEVCG_ACC_MKNOD	= (1ULL << 0),
6431	BPF_DEVCG_ACC_READ	= (1ULL << 1),
6432	BPF_DEVCG_ACC_WRITE	= (1ULL << 2),
6433};
6434
6435enum {
6436	BPF_DEVCG_DEV_BLOCK	= (1ULL << 0),
6437	BPF_DEVCG_DEV_CHAR	= (1ULL << 1),
6438};
6439
6440struct bpf_cgroup_dev_ctx {
6441	/* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
6442	__u32 access_type;
6443	__u32 major;
6444	__u32 minor;
6445};
6446
6447struct bpf_raw_tracepoint_args {
6448	__u64 args[0];
6449};
6450
6451/* DIRECT:  Skip the FIB rules and go to FIB table associated with device
6452 * OUTPUT:  Do lookup from egress perspective; default is ingress
6453 */
6454enum {
6455	BPF_FIB_LOOKUP_DIRECT  = (1U << 0),
6456	BPF_FIB_LOOKUP_OUTPUT  = (1U << 1),
6457};
6458
6459enum {
6460	BPF_FIB_LKUP_RET_SUCCESS,      /* lookup successful */
6461	BPF_FIB_LKUP_RET_BLACKHOLE,    /* dest is blackholed; can be dropped */
6462	BPF_FIB_LKUP_RET_UNREACHABLE,  /* dest is unreachable; can be dropped */
6463	BPF_FIB_LKUP_RET_PROHIBIT,     /* dest not allowed; can be dropped */
6464	BPF_FIB_LKUP_RET_NOT_FWDED,    /* packet is not forwarded */
6465	BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
6466	BPF_FIB_LKUP_RET_UNSUPP_LWT,   /* fwd requires encapsulation */
6467	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
6468	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6469};
6470
6471struct bpf_fib_lookup {
6472	/* input:  network family for lookup (AF_INET, AF_INET6)
6473	 * output: network family of egress nexthop
6474	 */
6475	__u8	family;
6476
6477	/* set if lookup is to consider L4 data - e.g., FIB rules */
6478	__u8	l4_protocol;
6479	__be16	sport;
6480	__be16	dport;
6481
6482	union {	/* used for MTU check */
6483		/* input to lookup */
6484		__u16	tot_len; /* L3 length from network hdr (iph->tot_len) */
6485
6486		/* output: MTU value */
6487		__u16	mtu_result;
6488	};
6489	/* input: L3 device index for lookup
6490	 * output: device index from FIB lookup
6491	 */
6492	__u32	ifindex;
6493
6494	union {
6495		/* inputs to lookup */
6496		__u8	tos;		/* AF_INET  */
6497		__be32	flowinfo;	/* AF_INET6, flow_label + priority */
6498
6499		/* output: metric of fib result (IPv4/IPv6 only) */
6500		__u32	rt_metric;
6501	};
6502
6503	union {
6504		__be32		ipv4_src;
6505		__u32		ipv6_src[4];  /* in6_addr; network order */
6506	};
6507
6508	/* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
6509	 * network header. output: bpf_fib_lookup sets to gateway address
6510	 * if FIB lookup returns gateway route
6511	 */
6512	union {
6513		__be32		ipv4_dst;
6514		__u32		ipv6_dst[4];  /* in6_addr; network order */
6515	};
6516
6517	/* output */
6518	__be16	h_vlan_proto;
6519	__be16	h_vlan_TCI;
6520	__u8	smac[6];     /* ETH_ALEN */
6521	__u8	dmac[6];     /* ETH_ALEN */
6522};
6523
6524struct bpf_redir_neigh {
6525	/* network family for lookup (AF_INET, AF_INET6) */
6526	__u32 nh_family;
6527	/* network address of nexthop; skips fib lookup to find gateway */
6528	union {
6529		__be32		ipv4_nh;
6530		__u32		ipv6_nh[4];  /* in6_addr; network order */
6531	};
6532};
6533
6534/* bpf_check_mtu flags*/
6535enum  bpf_check_mtu_flags {
6536	BPF_MTU_CHK_SEGS  = (1U << 0),
6537};
6538
6539enum bpf_check_mtu_ret {
6540	BPF_MTU_CHK_RET_SUCCESS,      /* check and lookup successful */
6541	BPF_MTU_CHK_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
6542	BPF_MTU_CHK_RET_SEGS_TOOBIG,  /* GSO re-segmentation needed to fwd */
6543};
6544
6545enum bpf_task_fd_type {
6546	BPF_FD_TYPE_RAW_TRACEPOINT,	/* tp name */
6547	BPF_FD_TYPE_TRACEPOINT,		/* tp name */
6548	BPF_FD_TYPE_KPROBE,		/* (symbol + offset) or addr */
6549	BPF_FD_TYPE_KRETPROBE,		/* (symbol + offset) or addr */
6550	BPF_FD_TYPE_UPROBE,		/* filename + offset */
6551	BPF_FD_TYPE_URETPROBE,		/* filename + offset */
6552};
6553
6554enum {
6555	BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG		= (1U << 0),
6556	BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL		= (1U << 1),
6557	BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP		= (1U << 2),
6558};
6559
6560struct bpf_flow_keys {
6561	__u16	nhoff;
6562	__u16	thoff;
6563	__u16	addr_proto;			/* ETH_P_* of valid addrs */
6564	__u8	is_frag;
6565	__u8	is_first_frag;
6566	__u8	is_encap;
6567	__u8	ip_proto;
6568	__be16	n_proto;
6569	__be16	sport;
6570	__be16	dport;
6571	union {
6572		struct {
6573			__be32	ipv4_src;
6574			__be32	ipv4_dst;
6575		};
6576		struct {
6577			__u32	ipv6_src[4];	/* in6_addr; network order */
6578			__u32	ipv6_dst[4];	/* in6_addr; network order */
6579		};
6580	};
6581	__u32	flags;
6582	__be32	flow_label;
6583};
6584
6585struct bpf_func_info {
6586	__u32	insn_off;
6587	__u32	type_id;
6588};
6589
6590#define BPF_LINE_INFO_LINE_NUM(line_col)	((line_col) >> 10)
6591#define BPF_LINE_INFO_LINE_COL(line_col)	((line_col) & 0x3ff)
6592
6593struct bpf_line_info {
6594	__u32	insn_off;
6595	__u32	file_name_off;
6596	__u32	line_off;
6597	__u32	line_col;
6598};
6599
6600struct bpf_spin_lock {
6601	__u32	val;
6602};
6603
6604struct bpf_timer {
6605	__u64 :64;
6606	__u64 :64;
6607} __attribute__((aligned(8)));
6608
6609struct bpf_dynptr {
6610	__u64 :64;
6611	__u64 :64;
6612} __attribute__((aligned(8)));
6613
6614struct bpf_sysctl {
6615	__u32	write;		/* Sysctl is being read (= 0) or written (= 1).
6616				 * Allows 1,2,4-byte read, but no write.
6617				 */
6618	__u32	file_pos;	/* Sysctl file position to read from, write to.
6619				 * Allows 1,2,4-byte read an 4-byte write.
6620				 */
6621};
6622
6623struct bpf_sockopt {
6624	__bpf_md_ptr(struct bpf_sock *, sk);
6625	__bpf_md_ptr(void *, optval);
6626	__bpf_md_ptr(void *, optval_end);
6627
6628	__s32	level;
6629	__s32	optname;
6630	__s32	optlen;
6631	__s32	retval;
6632};
6633
6634struct bpf_pidns_info {
6635	__u32 pid;
6636	__u32 tgid;
6637};
6638
6639/* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
6640struct bpf_sk_lookup {
6641	union {
6642		__bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
6643		__u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */
6644	};
6645
6646	__u32 family;		/* Protocol family (AF_INET, AF_INET6) */
6647	__u32 protocol;		/* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */
6648	__u32 remote_ip4;	/* Network byte order */
6649	__u32 remote_ip6[4];	/* Network byte order */
6650	__be16 remote_port;	/* Network byte order */
6651	__u16 :16;		/* Zero padding */
6652	__u32 local_ip4;	/* Network byte order */
6653	__u32 local_ip6[4];	/* Network byte order */
6654	__u32 local_port;	/* Host byte order */
6655	__u32 ingress_ifindex;		/* The arriving interface. Determined by inet_iif. */
6656};
6657
6658/*
6659 * struct btf_ptr is used for typed pointer representation; the
6660 * type id is used to render the pointer data as the appropriate type
6661 * via the bpf_snprintf_btf() helper described above.  A flags field -
6662 * potentially to specify additional details about the BTF pointer
6663 * (rather than its mode of display) - is included for future use.
6664 * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
6665 */
6666struct btf_ptr {
6667	void *ptr;
6668	__u32 type_id;
6669	__u32 flags;		/* BTF ptr flags; unused at present. */
6670};
6671
6672/*
6673 * Flags to control bpf_snprintf_btf() behaviour.
6674 *     - BTF_F_COMPACT: no formatting around type information
6675 *     - BTF_F_NONAME: no struct/union member names/types
6676 *     - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
6677 *       equivalent to %px.
6678 *     - BTF_F_ZERO: show zero-valued struct/union members; they
6679 *       are not displayed by default
6680 */
6681enum {
6682	BTF_F_COMPACT	=	(1ULL << 0),
6683	BTF_F_NONAME	=	(1ULL << 1),
6684	BTF_F_PTR_RAW	=	(1ULL << 2),
6685	BTF_F_ZERO	=	(1ULL << 3),
6686};
6687
6688/* bpf_core_relo_kind encodes which aspect of captured field/type/enum value
6689 * has to be adjusted by relocations. It is emitted by llvm and passed to
6690 * libbpf and later to the kernel.
6691 */
6692enum bpf_core_relo_kind {
6693	BPF_CORE_FIELD_BYTE_OFFSET = 0,      /* field byte offset */
6694	BPF_CORE_FIELD_BYTE_SIZE = 1,        /* field size in bytes */
6695	BPF_CORE_FIELD_EXISTS = 2,           /* field existence in target kernel */
6696	BPF_CORE_FIELD_SIGNED = 3,           /* field signedness (0 - unsigned, 1 - signed) */
6697	BPF_CORE_FIELD_LSHIFT_U64 = 4,       /* bitfield-specific left bitshift */
6698	BPF_CORE_FIELD_RSHIFT_U64 = 5,       /* bitfield-specific right bitshift */
6699	BPF_CORE_TYPE_ID_LOCAL = 6,          /* type ID in local BPF object */
6700	BPF_CORE_TYPE_ID_TARGET = 7,         /* type ID in target kernel */
6701	BPF_CORE_TYPE_EXISTS = 8,            /* type existence in target kernel */
6702	BPF_CORE_TYPE_SIZE = 9,              /* type size in bytes */
6703	BPF_CORE_ENUMVAL_EXISTS = 10,        /* enum value existence in target kernel */
6704	BPF_CORE_ENUMVAL_VALUE = 11,         /* enum value integer value */
6705};
6706
6707/*
6708 * "struct bpf_core_relo" is used to pass relocation data form LLVM to libbpf
6709 * and from libbpf to the kernel.
6710 *
6711 * CO-RE relocation captures the following data:
6712 * - insn_off - instruction offset (in bytes) within a BPF program that needs
6713 *   its insn->imm field to be relocated with actual field info;
6714 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable
6715 *   type or field;
6716 * - access_str_off - offset into corresponding .BTF string section. String
6717 *   interpretation depends on specific relocation kind:
6718 *     - for field-based relocations, string encodes an accessed field using
6719 *       a sequence of field and array indices, separated by colon (:). It's
6720 *       conceptually very close to LLVM's getelementptr ([0]) instruction's
6721 *       arguments for identifying offset to a field.
6722 *     - for type-based relocations, strings is expected to be just "0";
6723 *     - for enum value-based relocations, string contains an index of enum
6724 *       value within its enum type;
6725 * - kind - one of enum bpf_core_relo_kind;
6726 *
6727 * Example:
6728 *   struct sample {
6729 *       int a;
6730 *       struct {
6731 *           int b[10];
6732 *       };
6733 *   };
6734 *
6735 *   struct sample *s = ...;
6736 *   int *x = &s->a;     // encoded as "0:0" (a is field #0)
6737 *   int *y = &s->b[5];  // encoded as "0:1:0:5" (anon struct is field #1,
6738 *                       // b is field #0 inside anon struct, accessing elem #5)
6739 *   int *z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
6740 *
6741 * type_id for all relocs in this example will capture BTF type id of
6742 * `struct sample`.
6743 *
6744 * Such relocation is emitted when using __builtin_preserve_access_index()
6745 * Clang built-in, passing expression that captures field address, e.g.:
6746 *
6747 * bpf_probe_read(&dst, sizeof(dst),
6748 *		  __builtin_preserve_access_index(&src->a.b.c));
6749 *
6750 * In this case Clang will emit field relocation recording necessary data to
6751 * be able to find offset of embedded `a.b.c` field within `src` struct.
6752 *
6753 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
6754 */
6755struct bpf_core_relo {
6756	__u32 insn_off;
6757	__u32 type_id;
6758	__u32 access_str_off;
6759	enum bpf_core_relo_kind kind;
6760};
6761
6762#endif /* _UAPI__LINUX_BPF_H__ */
6763