1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _X_TABLES_H
3#define _X_TABLES_H
4
5
6#include <linux/netdevice.h>
7#include <linux/static_key.h>
8#include <linux/netfilter.h>
9#include <uapi/linux/netfilter/x_tables.h>
10
11/* Test a struct->invflags and a boolean for inequality */
12#define NF_INVF(ptr, flag, boolean)					\
13	((boolean) ^ !!((ptr)->invflags & (flag)))
14
15/**
16 * struct xt_action_param - parameters for matches/targets
17 *
18 * @match:	the match extension
19 * @target:	the target extension
20 * @matchinfo:	per-match data
21 * @targetinfo:	per-target data
22 * @state:	pointer to hook state this packet came from
23 * @fragoff:	packet is a fragment, this is the data offset
24 * @thoff:	position of transport header relative to skb->data
25 *
26 * Fields written to by extensions:
27 *
28 * @hotdrop:	drop packet if we had inspection problems
29 */
30struct xt_action_param {
31	union {
32		const struct xt_match *match;
33		const struct xt_target *target;
34	};
35	union {
36		const void *matchinfo, *targinfo;
37	};
38	const struct nf_hook_state *state;
39	unsigned int thoff;
40	u16 fragoff;
41	bool hotdrop;
42};
43
44static inline struct net *xt_net(const struct xt_action_param *par)
45{
46	return par->state->net;
47}
48
49static inline struct net_device *xt_in(const struct xt_action_param *par)
50{
51	return par->state->in;
52}
53
54static inline const char *xt_inname(const struct xt_action_param *par)
55{
56	return par->state->in->name;
57}
58
59static inline struct net_device *xt_out(const struct xt_action_param *par)
60{
61	return par->state->out;
62}
63
64static inline const char *xt_outname(const struct xt_action_param *par)
65{
66	return par->state->out->name;
67}
68
69static inline unsigned int xt_hooknum(const struct xt_action_param *par)
70{
71	return par->state->hook;
72}
73
74static inline u_int8_t xt_family(const struct xt_action_param *par)
75{
76	return par->state->pf;
77}
78
79/**
80 * struct xt_mtchk_param - parameters for match extensions'
81 * checkentry functions
82 *
83 * @net:	network namespace through which the check was invoked
84 * @table:	table the rule is tried to be inserted into
85 * @entryinfo:	the family-specific rule data
86 * 		(struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry)
87 * @match:	struct xt_match through which this function was invoked
88 * @matchinfo:	per-match data
89 * @hook_mask:	via which hooks the new rule is reachable
90 * Other fields as above.
91 */
92struct xt_mtchk_param {
93	struct net *net;
94	const char *table;
95	const void *entryinfo;
96	const struct xt_match *match;
97	void *matchinfo;
98	unsigned int hook_mask;
99	u_int8_t family;
100	bool nft_compat;
101};
102
103/**
104 * struct xt_mdtor_param - match destructor parameters
105 * Fields as above.
106 */
107struct xt_mtdtor_param {
108	struct net *net;
109	const struct xt_match *match;
110	void *matchinfo;
111	u_int8_t family;
112};
113
114/**
115 * struct xt_tgchk_param - parameters for target extensions'
116 * checkentry functions
117 *
118 * @entryinfo:	the family-specific rule data
119 * 		(struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
120 *
121 * Other fields see above.
122 */
123struct xt_tgchk_param {
124	struct net *net;
125	const char *table;
126	const void *entryinfo;
127	const struct xt_target *target;
128	void *targinfo;
129	unsigned int hook_mask;
130	u_int8_t family;
131	bool nft_compat;
132};
133
134/* Target destructor parameters */
135struct xt_tgdtor_param {
136	struct net *net;
137	const struct xt_target *target;
138	void *targinfo;
139	u_int8_t family;
140};
141
142struct xt_match {
143	struct list_head list;
144
145	const char name[XT_EXTENSION_MAXNAMELEN];
146	u_int8_t revision;
147
148	/* Return true or false: return FALSE and set *hotdrop = 1 to
149           force immediate packet drop. */
150	/* Arguments changed since 2.6.9, as this must now handle
151	   non-linear skb, using skb_header_pointer and
152	   skb_ip_make_writable. */
153	bool (*match)(const struct sk_buff *skb,
154		      struct xt_action_param *);
155
156	/* Called when user tries to insert an entry of this type. */
157	int (*checkentry)(const struct xt_mtchk_param *);
158
159	/* Called when entry of this type deleted. */
160	void (*destroy)(const struct xt_mtdtor_param *);
161#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
162	/* Called when userspace align differs from kernel space one */
163	void (*compat_from_user)(void *dst, const void *src);
164	int (*compat_to_user)(void __user *dst, const void *src);
165#endif
166	/* Set this to THIS_MODULE if you are a module, otherwise NULL */
167	struct module *me;
168
169	const char *table;
170	unsigned int matchsize;
171	unsigned int usersize;
172#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
173	unsigned int compatsize;
174#endif
175	unsigned int hooks;
176	unsigned short proto;
177
178	unsigned short family;
179};
180
181/* Registration hooks for targets. */
182struct xt_target {
183	struct list_head list;
184
185	const char name[XT_EXTENSION_MAXNAMELEN];
186	u_int8_t revision;
187
188	/* Returns verdict. Argument order changed since 2.6.9, as this
189	   must now handle non-linear skbs, using skb_copy_bits and
190	   skb_ip_make_writable. */
191	unsigned int (*target)(struct sk_buff *skb,
192			       const struct xt_action_param *);
193
194	/* Called when user tries to insert an entry of this type:
195           hook_mask is a bitmask of hooks from which it can be
196           called. */
197	/* Should return 0 on success or an error code otherwise (-Exxxx). */
198	int (*checkentry)(const struct xt_tgchk_param *);
199
200	/* Called when entry of this type deleted. */
201	void (*destroy)(const struct xt_tgdtor_param *);
202#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
203	/* Called when userspace align differs from kernel space one */
204	void (*compat_from_user)(void *dst, const void *src);
205	int (*compat_to_user)(void __user *dst, const void *src);
206#endif
207	/* Set this to THIS_MODULE if you are a module, otherwise NULL */
208	struct module *me;
209
210	const char *table;
211	unsigned int targetsize;
212	unsigned int usersize;
213#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
214	unsigned int compatsize;
215#endif
216	unsigned int hooks;
217	unsigned short proto;
218
219	unsigned short family;
220};
221
222/* Furniture shopping... */
223struct xt_table {
224	struct list_head list;
225
226	/* What hooks you will enter on */
227	unsigned int valid_hooks;
228
229	/* Man behind the curtain... */
230	struct xt_table_info *private;
231
232	/* hook ops that register the table with the netfilter core */
233	struct nf_hook_ops *ops;
234
235	/* Set this to THIS_MODULE if you are a module, otherwise NULL */
236	struct module *me;
237
238	u_int8_t af;		/* address/protocol family */
239	int priority;		/* hook order */
240
241	/* A unique name... */
242	const char name[XT_TABLE_MAXNAMELEN];
243};
244
245#include <linux/netfilter_ipv4.h>
246
247/* The table itself */
248struct xt_table_info {
249	/* Size per table */
250	unsigned int size;
251	/* Number of entries: FIXME. --RR */
252	unsigned int number;
253	/* Initial number of entries. Needed for module usage count */
254	unsigned int initial_entries;
255
256	/* Entry points and underflows */
257	unsigned int hook_entry[NF_INET_NUMHOOKS];
258	unsigned int underflow[NF_INET_NUMHOOKS];
259
260	/*
261	 * Number of user chains. Since tables cannot have loops, at most
262	 * @stacksize jumps (number of user chains) can possibly be made.
263	 */
264	unsigned int stacksize;
265	void ***jumpstack;
266
267	unsigned char entries[] __aligned(8);
268};
269
270int xt_register_target(struct xt_target *target);
271void xt_unregister_target(struct xt_target *target);
272int xt_register_targets(struct xt_target *target, unsigned int n);
273void xt_unregister_targets(struct xt_target *target, unsigned int n);
274
275int xt_register_match(struct xt_match *target);
276void xt_unregister_match(struct xt_match *target);
277int xt_register_matches(struct xt_match *match, unsigned int n);
278void xt_unregister_matches(struct xt_match *match, unsigned int n);
279
280int xt_check_entry_offsets(const void *base, const char *elems,
281			   unsigned int target_offset,
282			   unsigned int next_offset);
283
284int xt_check_table_hooks(const struct xt_table_info *info, unsigned int valid_hooks);
285
286unsigned int *xt_alloc_entry_offsets(unsigned int size);
287bool xt_find_jump_offset(const unsigned int *offsets,
288			 unsigned int target, unsigned int size);
289
290int xt_check_proc_name(const char *name, unsigned int size);
291
292int xt_check_match(struct xt_mtchk_param *, unsigned int size, u16 proto,
293		   bool inv_proto);
294int xt_check_target(struct xt_tgchk_param *, unsigned int size, u16 proto,
295		    bool inv_proto);
296
297int xt_match_to_user(const struct xt_entry_match *m,
298		     struct xt_entry_match __user *u);
299int xt_target_to_user(const struct xt_entry_target *t,
300		      struct xt_entry_target __user *u);
301int xt_data_to_user(void __user *dst, const void *src,
302		    int usersize, int size, int aligned_size);
303
304void *xt_copy_counters(sockptr_t arg, unsigned int len,
305		       struct xt_counters_info *info);
306struct xt_counters *xt_counters_alloc(unsigned int counters);
307
308struct xt_table *xt_register_table(struct net *net,
309				   const struct xt_table *table,
310				   struct xt_table_info *bootstrap,
311				   struct xt_table_info *newinfo);
312void *xt_unregister_table(struct xt_table *table);
313
314struct xt_table_info *xt_replace_table(struct xt_table *table,
315				       unsigned int num_counters,
316				       struct xt_table_info *newinfo,
317				       int *error);
318
319struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
320struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision);
321struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision);
322int xt_find_revision(u8 af, const char *name, u8 revision, int target,
323		     int *err);
324
325struct xt_table *xt_find_table(struct net *net, u8 af, const char *name);
326struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
327				    const char *name);
328struct xt_table *xt_request_find_table_lock(struct net *net, u_int8_t af,
329					    const char *name);
330void xt_table_unlock(struct xt_table *t);
331
332int xt_proto_init(struct net *net, u_int8_t af);
333void xt_proto_fini(struct net *net, u_int8_t af);
334
335struct xt_table_info *xt_alloc_table_info(unsigned int size);
336void xt_free_table_info(struct xt_table_info *info);
337
338/**
339 * xt_recseq - recursive seqcount for netfilter use
340 *
341 * Packet processing changes the seqcount only if no recursion happened
342 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
343 * because we use the normal seqcount convention :
344 * Low order bit set to 1 if a writer is active.
345 */
346DECLARE_PER_CPU(seqcount_t, xt_recseq);
347
348/* xt_tee_enabled - true if x_tables needs to handle reentrancy
349 *
350 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
351 */
352extern struct static_key xt_tee_enabled;
353
354/**
355 * xt_write_recseq_begin - start of a write section
356 *
357 * Begin packet processing : all readers must wait the end
358 * 1) Must be called with preemption disabled
359 * 2) softirqs must be disabled too (or we should use this_cpu_add())
360 * Returns :
361 *  1 if no recursion on this cpu
362 *  0 if recursion detected
363 */
364static inline unsigned int xt_write_recseq_begin(void)
365{
366	unsigned int addend;
367
368	/*
369	 * Low order bit of sequence is set if we already
370	 * called xt_write_recseq_begin().
371	 */
372	addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
373
374	/*
375	 * This is kind of a write_seqcount_begin(), but addend is 0 or 1
376	 * We dont check addend value to avoid a test and conditional jump,
377	 * since addend is most likely 1
378	 */
379	__this_cpu_add(xt_recseq.sequence, addend);
380	smp_mb();
381
382	return addend;
383}
384
385/**
386 * xt_write_recseq_end - end of a write section
387 * @addend: return value from previous xt_write_recseq_begin()
388 *
389 * End packet processing : all readers can proceed
390 * 1) Must be called with preemption disabled
391 * 2) softirqs must be disabled too (or we should use this_cpu_add())
392 */
393static inline void xt_write_recseq_end(unsigned int addend)
394{
395	/* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
396	smp_wmb();
397	__this_cpu_add(xt_recseq.sequence, addend);
398}
399
400/*
401 * This helper is performance critical and must be inlined
402 */
403static inline unsigned long ifname_compare_aligned(const char *_a,
404						   const char *_b,
405						   const char *_mask)
406{
407	const unsigned long *a = (const unsigned long *)_a;
408	const unsigned long *b = (const unsigned long *)_b;
409	const unsigned long *mask = (const unsigned long *)_mask;
410	unsigned long ret;
411
412	ret = (a[0] ^ b[0]) & mask[0];
413	if (IFNAMSIZ > sizeof(unsigned long))
414		ret |= (a[1] ^ b[1]) & mask[1];
415	if (IFNAMSIZ > 2 * sizeof(unsigned long))
416		ret |= (a[2] ^ b[2]) & mask[2];
417	if (IFNAMSIZ > 3 * sizeof(unsigned long))
418		ret |= (a[3] ^ b[3]) & mask[3];
419	BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
420	return ret;
421}
422
423struct xt_percpu_counter_alloc_state {
424	unsigned int off;
425	const char __percpu *mem;
426};
427
428bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state,
429			     struct xt_counters *counter);
430void xt_percpu_counter_free(struct xt_counters *cnt);
431
432static inline struct xt_counters *
433xt_get_this_cpu_counter(struct xt_counters *cnt)
434{
435	if (nr_cpu_ids > 1)
436		return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt);
437
438	return cnt;
439}
440
441static inline struct xt_counters *
442xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
443{
444	if (nr_cpu_ids > 1)
445		return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu);
446
447	return cnt;
448}
449
450struct nf_hook_ops *xt_hook_ops_alloc(const struct xt_table *, nf_hookfn *);
451
452int xt_register_template(const struct xt_table *t, int(*table_init)(struct net *net));
453void xt_unregister_template(const struct xt_table *t);
454
455#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
456#include <net/compat.h>
457
458struct compat_xt_entry_match {
459	union {
460		struct {
461			u_int16_t match_size;
462			char name[XT_FUNCTION_MAXNAMELEN - 1];
463			u_int8_t revision;
464		} user;
465		struct {
466			u_int16_t match_size;
467			compat_uptr_t match;
468		} kernel;
469		u_int16_t match_size;
470	} u;
471	unsigned char data[];
472};
473
474struct compat_xt_entry_target {
475	union {
476		struct {
477			u_int16_t target_size;
478			char name[XT_FUNCTION_MAXNAMELEN - 1];
479			u_int8_t revision;
480		} user;
481		struct {
482			u_int16_t target_size;
483			compat_uptr_t target;
484		} kernel;
485		u_int16_t target_size;
486	} u;
487	unsigned char data[];
488};
489
490/* FIXME: this works only on 32 bit tasks
491 * need to change whole approach in order to calculate align as function of
492 * current task alignment */
493
494struct compat_xt_counters {
495	compat_u64 pcnt, bcnt;			/* Packet and byte counters */
496};
497
498struct compat_xt_counters_info {
499	char name[XT_TABLE_MAXNAMELEN];
500	compat_uint_t num_counters;
501	struct compat_xt_counters counters[];
502};
503
504struct _compat_xt_align {
505	__u8 u8;
506	__u16 u16;
507	__u32 u32;
508	compat_u64 u64;
509};
510
511#define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
512
513void xt_compat_lock(u_int8_t af);
514void xt_compat_unlock(u_int8_t af);
515
516int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
517void xt_compat_flush_offsets(u_int8_t af);
518int xt_compat_init_offsets(u8 af, unsigned int number);
519int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
520
521int xt_compat_match_offset(const struct xt_match *match);
522void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
523			      unsigned int *size);
524int xt_compat_match_to_user(const struct xt_entry_match *m,
525			    void __user **dstptr, unsigned int *size);
526
527int xt_compat_target_offset(const struct xt_target *target);
528void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
529				unsigned int *size);
530int xt_compat_target_to_user(const struct xt_entry_target *t,
531			     void __user **dstptr, unsigned int *size);
532int xt_compat_check_entry_offsets(const void *base, const char *elems,
533				  unsigned int target_offset,
534				  unsigned int next_offset);
535
536#endif /* CONFIG_NETFILTER_XTABLES_COMPAT */
537#endif /* _X_TABLES_H */
538