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 */
30 struct 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 int fragoff;
40 unsigned int thoff;
41 bool hotdrop;
42 };
43
44 static inline struct net *xt_net(const struct xt_action_param *par)
45 {
46 return par->state->net;
47 }
48
49 static inline struct net_device *xt_in(const struct xt_action_param *par)
50 {
51 return par->state->in;
52 }
53
54 static inline const char *xt_inname(const struct xt_action_param *par)
55 {
56 return par->state->in->name;
57 }
58
59 static inline struct net_device *xt_out(const struct xt_action_param *par)
60 {
61 return par->state->out;
62 }
63
64 static inline const char *xt_outname(const struct xt_action_param *par)
65 {
66 return par->state->out->name;
67 }
68
69 static inline unsigned int xt_hooknum(const struct xt_action_param *par)
70 {
71 return par->state->hook;
72 }
73
74 static 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 */
92 struct 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 */
107 struct 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 */
123 struct 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 */
135 struct xt_tgdtor_param {
136 struct net *net;
137 const struct xt_target *target;
138 void *targinfo;
139 u_int8_t family;
140 };
141
142 struct 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_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_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. */
182 struct 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_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_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... */
223 struct 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 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
233 struct module *me;
234
235 u_int8_t af; /* address/protocol family */
236 int priority; /* hook order */
237
238 /* called when table is needed in the given netns */
239 int (*table_init)(struct net *net);
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 */
248 struct 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[0] __aligned(8);
268 };
269
270 int xt_register_target(struct xt_target *target);
271 void xt_unregister_target(struct xt_target *target);
272 int xt_register_targets(struct xt_target *target, unsigned int n);
273 void xt_unregister_targets(struct xt_target *target, unsigned int n);
274
275 int xt_register_match(struct xt_match *target);
276 void xt_unregister_match(struct xt_match *target);
277 int xt_register_matches(struct xt_match *match, unsigned int n);
278 void xt_unregister_matches(struct xt_match *match, unsigned int n);
279
280 int xt_check_entry_offsets(const void *base, const char *elems,
281 unsigned int target_offset,
282 unsigned int next_offset);
283
284 unsigned int *xt_alloc_entry_offsets(unsigned int size);
285 bool xt_find_jump_offset(const unsigned int *offsets,
286 unsigned int target, unsigned int size);
287
288 int xt_check_proc_name(const char *name, unsigned int size);
289
290 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
291 bool inv_proto);
292 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
293 bool inv_proto);
294
295 int xt_match_to_user(const struct xt_entry_match *m,
296 struct xt_entry_match __user *u);
297 int xt_target_to_user(const struct xt_entry_target *t,
298 struct xt_entry_target __user *u);
299 int xt_data_to_user(void __user *dst, const void *src,
300 int usersize, int size, int aligned_size);
301
302 void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
303 struct xt_counters_info *info, bool compat);
304 struct xt_counters *xt_counters_alloc(unsigned int counters);
305
306 struct xt_table *xt_register_table(struct net *net,
307 const struct xt_table *table,
308 struct xt_table_info *bootstrap,
309 struct xt_table_info *newinfo);
310 void *xt_unregister_table(struct xt_table *table);
311
312 struct xt_table_info *xt_replace_table(struct xt_table *table,
313 unsigned int num_counters,
314 struct xt_table_info *newinfo,
315 int *error);
316
317 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
318 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
319 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision);
320 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision);
321 int xt_find_revision(u8 af, const char *name, u8 revision, int target,
322 int *err);
323
324 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
325 const char *name);
326 struct xt_table *xt_request_find_table_lock(struct net *net, u_int8_t af,
327 const char *name);
328 void xt_table_unlock(struct xt_table *t);
329
330 int xt_proto_init(struct net *net, u_int8_t af);
331 void xt_proto_fini(struct net *net, u_int8_t af);
332
333 struct xt_table_info *xt_alloc_table_info(unsigned int size);
334 void xt_free_table_info(struct xt_table_info *info);
335
336 /**
337 * xt_recseq - recursive seqcount for netfilter use
338 *
339 * Packet processing changes the seqcount only if no recursion happened
340 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
341 * because we use the normal seqcount convention :
342 * Low order bit set to 1 if a writer is active.
343 */
344 DECLARE_PER_CPU(seqcount_t, xt_recseq);
345
346 /* xt_tee_enabled - true if x_tables needs to handle reentrancy
347 *
348 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
349 */
350 extern struct static_key xt_tee_enabled;
351
352 /**
353 * xt_write_recseq_begin - start of a write section
354 *
355 * Begin packet processing : all readers must wait the end
356 * 1) Must be called with preemption disabled
357 * 2) softirqs must be disabled too (or we should use this_cpu_add())
358 * Returns :
359 * 1 if no recursion on this cpu
360 * 0 if recursion detected
361 */
362 static inline unsigned int xt_write_recseq_begin(void)
363 {
364 unsigned int addend;
365
366 /*
367 * Low order bit of sequence is set if we already
368 * called xt_write_recseq_begin().
369 */
370 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
371
372 /*
373 * This is kind of a write_seqcount_begin(), but addend is 0 or 1
374 * We dont check addend value to avoid a test and conditional jump,
375 * since addend is most likely 1
376 */
377 __this_cpu_add(xt_recseq.sequence, addend);
378 smp_wmb();
379
380 return addend;
381 }
382
383 /**
384 * xt_write_recseq_end - end of a write section
385 * @addend: return value from previous xt_write_recseq_begin()
386 *
387 * End packet processing : all readers can proceed
388 * 1) Must be called with preemption disabled
389 * 2) softirqs must be disabled too (or we should use this_cpu_add())
390 */
391 static inline void xt_write_recseq_end(unsigned int addend)
392 {
393 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
394 smp_wmb();
395 __this_cpu_add(xt_recseq.sequence, addend);
396 }
397
398 /*
399 * This helper is performance critical and must be inlined
400 */
401 static inline unsigned long ifname_compare_aligned(const char *_a,
402 const char *_b,
403 const char *_mask)
404 {
405 const unsigned long *a = (const unsigned long *)_a;
406 const unsigned long *b = (const unsigned long *)_b;
407 const unsigned long *mask = (const unsigned long *)_mask;
408 unsigned long ret;
409
410 ret = (a[0] ^ b[0]) & mask[0];
411 if (IFNAMSIZ > sizeof(unsigned long))
412 ret |= (a[1] ^ b[1]) & mask[1];
413 if (IFNAMSIZ > 2 * sizeof(unsigned long))
414 ret |= (a[2] ^ b[2]) & mask[2];
415 if (IFNAMSIZ > 3 * sizeof(unsigned long))
416 ret |= (a[3] ^ b[3]) & mask[3];
417 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
418 return ret;
419 }
420
421 struct xt_percpu_counter_alloc_state {
422 unsigned int off;
423 const char __percpu *mem;
424 };
425
426 bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state,
427 struct xt_counters *counter);
428 void xt_percpu_counter_free(struct xt_counters *cnt);
429
430 static inline struct xt_counters *
431 xt_get_this_cpu_counter(struct xt_counters *cnt)
432 {
433 if (nr_cpu_ids > 1)
434 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt);
435
436 return cnt;
437 }
438
439 static inline struct xt_counters *
440 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
441 {
442 if (nr_cpu_ids > 1)
443 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu);
444
445 return cnt;
446 }
447
448 struct nf_hook_ops *xt_hook_ops_alloc(const struct xt_table *, nf_hookfn *);
449
450 #ifdef CONFIG_COMPAT
451 #include <net/compat.h>
452
453 struct compat_xt_entry_match {
454 union {
455 struct {
456 u_int16_t match_size;
457 char name[XT_FUNCTION_MAXNAMELEN - 1];
458 u_int8_t revision;
459 } user;
460 struct {
461 u_int16_t match_size;
462 compat_uptr_t match;
463 } kernel;
464 u_int16_t match_size;
465 } u;
466 unsigned char data[0];
467 };
468
469 struct compat_xt_entry_target {
470 union {
471 struct {
472 u_int16_t target_size;
473 char name[XT_FUNCTION_MAXNAMELEN - 1];
474 u_int8_t revision;
475 } user;
476 struct {
477 u_int16_t target_size;
478 compat_uptr_t target;
479 } kernel;
480 u_int16_t target_size;
481 } u;
482 unsigned char data[0];
483 };
484
485 /* FIXME: this works only on 32 bit tasks
486 * need to change whole approach in order to calculate align as function of
487 * current task alignment */
488
489 struct compat_xt_counters {
490 compat_u64 pcnt, bcnt; /* Packet and byte counters */
491 };
492
493 struct compat_xt_counters_info {
494 char name[XT_TABLE_MAXNAMELEN];
495 compat_uint_t num_counters;
496 struct compat_xt_counters counters[0];
497 };
498
499 struct _compat_xt_align {
500 __u8 u8;
501 __u16 u16;
502 __u32 u32;
503 compat_u64 u64;
504 };
505
506 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
507
508 void xt_compat_lock(u_int8_t af);
509 void xt_compat_unlock(u_int8_t af);
510
511 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
512 void xt_compat_flush_offsets(u_int8_t af);
513 int xt_compat_init_offsets(u8 af, unsigned int number);
514 int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
515
516 int xt_compat_match_offset(const struct xt_match *match);
517 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
518 unsigned int *size);
519 int xt_compat_match_to_user(const struct xt_entry_match *m,
520 void __user **dstptr, unsigned int *size);
521
522 int xt_compat_target_offset(const struct xt_target *target);
523 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
524 unsigned int *size);
525 int xt_compat_target_to_user(const struct xt_entry_target *t,
526 void __user **dstptr, unsigned int *size);
527 int xt_compat_check_entry_offsets(const void *base, const char *elems,
528 unsigned int target_offset,
529 unsigned int next_offset);
530
531 #endif /* CONFIG_COMPAT */
532 #endif /* _X_TABLES_H */
533
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