1 #ifndef _X_TABLES_H
2 #define _X_TABLES_H
3 #include <linux/kernel.h>
4 #include <linux/types.h>
5
6 #define XT_FUNCTION_MAXNAMELEN 30
7 #define XT_EXTENSION_MAXNAMELEN 29
8 #define XT_TABLE_MAXNAMELEN 32
9
10 struct xt_entry_match {
11 union {
12 struct {
13 __u16 match_size;
14
15 /* Used by userspace */
16 char name[XT_EXTENSION_MAXNAMELEN];
17 __u8 revision;
18 } user;
19 struct {
20 __u16 match_size;
21
22 /* Used inside the kernel */
23 struct xt_match *match;
24 } kernel;
25
26 /* Total length */
27 __u16 match_size;
28 } u;
29
30 unsigned char data[0];
31 };
32
33 struct xt_entry_target {
34 union {
35 struct {
36 __u16 target_size;
37
38 /* Used by userspace */
39 char name[XT_EXTENSION_MAXNAMELEN];
40 __u8 revision;
41 } user;
42 struct {
43 __u16 target_size;
44
45 /* Used inside the kernel */
46 struct xt_target *target;
47 } kernel;
48
49 /* Total length */
50 __u16 target_size;
51 } u;
52
53 unsigned char data[0];
54 };
55
56 #define XT_TARGET_INIT(__name, __size) \
57 { \
58 .target.u.user = { \
59 .target_size = XT_ALIGN(__size), \
60 .name = __name, \
61 }, \
62 }
63
64 struct xt_standard_target {
65 struct xt_entry_target target;
66 int verdict;
67 };
68
69 struct xt_error_target {
70 struct xt_entry_target target;
71 char errorname[XT_FUNCTION_MAXNAMELEN];
72 };
73
74 /* The argument to IPT_SO_GET_REVISION_*. Returns highest revision
75 * kernel supports, if >= revision. */
76 struct xt_get_revision {
77 char name[XT_EXTENSION_MAXNAMELEN];
78 __u8 revision;
79 };
80
81 /* CONTINUE verdict for targets */
82 #define XT_CONTINUE 0xFFFFFFFF
83
84 /* For standard target */
85 #define XT_RETURN (-NF_REPEAT - 1)
86
87 /* this is a dummy structure to find out the alignment requirement for a struct
88 * containing all the fundamental data types that are used in ipt_entry,
89 * ip6t_entry and arpt_entry. This sucks, and it is a hack. It will be my
90 * personal pleasure to remove it -HW
91 */
92 struct _xt_align {
93 __u8 u8;
94 __u16 u16;
95 __u32 u32;
96 __u64 u64;
97 };
98
99 #define XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _xt_align))
100
101 /* Standard return verdict, or do jump. */
102 #define XT_STANDARD_TARGET ""
103 /* Error verdict. */
104 #define XT_ERROR_TARGET "ERROR"
105
106 #define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0)
107 #define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
108
109 struct xt_counters {
110 __u64 pcnt, bcnt; /* Packet and byte counters */
111 };
112
113 /* The argument to IPT_SO_ADD_COUNTERS. */
114 struct xt_counters_info {
115 /* Which table. */
116 char name[XT_TABLE_MAXNAMELEN];
117
118 unsigned int num_counters;
119
120 /* The counters (actually `number' of these). */
121 struct xt_counters counters[0];
122 };
123
124 #define XT_INV_PROTO 0x40 /* Invert the sense of PROTO. */
125
126 #ifndef __KERNEL__
127 /* fn returns 0 to continue iteration */
128 #define XT_MATCH_ITERATE(type, e, fn, args...) \
129 ({ \
130 unsigned int __i; \
131 int __ret = 0; \
132 struct xt_entry_match *__m; \
133 \
134 for (__i = sizeof(type); \
135 __i < (e)->target_offset; \
136 __i += __m->u.match_size) { \
137 __m = (void *)e + __i; \
138 \
139 __ret = fn(__m , ## args); \
140 if (__ret != 0) \
141 break; \
142 } \
143 __ret; \
144 })
145
146 /* fn returns 0 to continue iteration */
147 #define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
148 ({ \
149 unsigned int __i, __n; \
150 int __ret = 0; \
151 type *__entry; \
152 \
153 for (__i = 0, __n = 0; __i < (size); \
154 __i += __entry->next_offset, __n++) { \
155 __entry = (void *)(entries) + __i; \
156 if (__n < n) \
157 continue; \
158 \
159 __ret = fn(__entry , ## args); \
160 if (__ret != 0) \
161 break; \
162 } \
163 __ret; \
164 })
165
166 /* fn returns 0 to continue iteration */
167 #define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
168 XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)
169
170 #endif /* !__KERNEL__ */
171
172 /* pos is normally a struct ipt_entry/ip6t_entry/etc. */
173 #define xt_entry_foreach(pos, ehead, esize) \
174 for ((pos) = (typeof(pos))(ehead); \
175 (pos) < (typeof(pos))((char *)(ehead) + (esize)); \
176 (pos) = (typeof(pos))((char *)(pos) + (pos)->next_offset))
177
178 /* can only be xt_entry_match, so no use of typeof here */
179 #define xt_ematch_foreach(pos, entry) \
180 for ((pos) = (struct xt_entry_match *)entry->elems; \
181 (pos) < (struct xt_entry_match *)((char *)(entry) + \
182 (entry)->target_offset); \
183 (pos) = (struct xt_entry_match *)((char *)(pos) + \
184 (pos)->u.match_size))
185
186 #ifdef __KERNEL__
187
188 #include <linux/netdevice.h>
189
190 /**
191 * struct xt_action_param - parameters for matches/targets
192 *
193 * @match: the match extension
194 * @target: the target extension
195 * @matchinfo: per-match data
196 * @targetinfo: per-target data
197 * @in: input netdevice
198 * @out: output netdevice
199 * @fragoff: packet is a fragment, this is the data offset
200 * @thoff: position of transport header relative to skb->data
201 * @hook: hook number given packet came from
202 * @family: Actual NFPROTO_* through which the function is invoked
203 * (helpful when match->family == NFPROTO_UNSPEC)
204 *
205 * Fields written to by extensions:
206 *
207 * @hotdrop: drop packet if we had inspection problems
208 * Network namespace obtainable using dev_net(in/out)
209 */
210 struct xt_action_param {
211 union {
212 const struct xt_match *match;
213 const struct xt_target *target;
214 };
215 union {
216 const void *matchinfo, *targinfo;
217 };
218 const struct net_device *in, *out;
219 int fragoff;
220 unsigned int thoff;
221 unsigned int hooknum;
222 u_int8_t family;
223 bool hotdrop;
224 };
225
226 /**
227 * struct xt_mtchk_param - parameters for match extensions'
228 * checkentry functions
229 *
230 * @net: network namespace through which the check was invoked
231 * @table: table the rule is tried to be inserted into
232 * @entryinfo: the family-specific rule data
233 * (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry)
234 * @match: struct xt_match through which this function was invoked
235 * @matchinfo: per-match data
236 * @hook_mask: via which hooks the new rule is reachable
237 * Other fields as above.
238 */
239 struct xt_mtchk_param {
240 struct net *net;
241 const char *table;
242 const void *entryinfo;
243 const struct xt_match *match;
244 void *matchinfo;
245 unsigned int hook_mask;
246 u_int8_t family;
247 };
248
249 /**
250 * struct xt_mdtor_param - match destructor parameters
251 * Fields as above.
252 */
253 struct xt_mtdtor_param {
254 struct net *net;
255 const struct xt_match *match;
256 void *matchinfo;
257 u_int8_t family;
258 };
259
260 /**
261 * struct xt_tgchk_param - parameters for target extensions'
262 * checkentry functions
263 *
264 * @entryinfo: the family-specific rule data
265 * (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
266 *
267 * Other fields see above.
268 */
269 struct xt_tgchk_param {
270 struct net *net;
271 const char *table;
272 const void *entryinfo;
273 const struct xt_target *target;
274 void *targinfo;
275 unsigned int hook_mask;
276 u_int8_t family;
277 };
278
279 /* Target destructor parameters */
280 struct xt_tgdtor_param {
281 struct net *net;
282 const struct xt_target *target;
283 void *targinfo;
284 u_int8_t family;
285 };
286
287 struct xt_match {
288 struct list_head list;
289
290 const char name[XT_EXTENSION_MAXNAMELEN];
291 u_int8_t revision;
292
293 /* Return true or false: return FALSE and set *hotdrop = 1 to
294 force immediate packet drop. */
295 /* Arguments changed since 2.6.9, as this must now handle
296 non-linear skb, using skb_header_pointer and
297 skb_ip_make_writable. */
298 bool (*match)(const struct sk_buff *skb,
299 struct xt_action_param *);
300
301 /* Called when user tries to insert an entry of this type. */
302 int (*checkentry)(const struct xt_mtchk_param *);
303
304 /* Called when entry of this type deleted. */
305 void (*destroy)(const struct xt_mtdtor_param *);
306 #ifdef CONFIG_COMPAT
307 /* Called when userspace align differs from kernel space one */
308 void (*compat_from_user)(void *dst, const void *src);
309 int (*compat_to_user)(void __user *dst, const void *src);
310 #endif
311 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
312 struct module *me;
313
314 const char *table;
315 unsigned int matchsize;
316 #ifdef CONFIG_COMPAT
317 unsigned int compatsize;
318 #endif
319 unsigned int hooks;
320 unsigned short proto;
321
322 unsigned short family;
323 };
324
325 /* Registration hooks for targets. */
326 struct xt_target {
327 struct list_head list;
328
329 const char name[XT_EXTENSION_MAXNAMELEN];
330 u_int8_t revision;
331
332 /* Returns verdict. Argument order changed since 2.6.9, as this
333 must now handle non-linear skbs, using skb_copy_bits and
334 skb_ip_make_writable. */
335 unsigned int (*target)(struct sk_buff *skb,
336 const struct xt_action_param *);
337
338 /* Called when user tries to insert an entry of this type:
339 hook_mask is a bitmask of hooks from which it can be
340 called. */
341 /* Should return 0 on success or an error code otherwise (-Exxxx). */
342 int (*checkentry)(const struct xt_tgchk_param *);
343
344 /* Called when entry of this type deleted. */
345 void (*destroy)(const struct xt_tgdtor_param *);
346 #ifdef CONFIG_COMPAT
347 /* Called when userspace align differs from kernel space one */
348 void (*compat_from_user)(void *dst, const void *src);
349 int (*compat_to_user)(void __user *dst, const void *src);
350 #endif
351 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
352 struct module *me;
353
354 const char *table;
355 unsigned int targetsize;
356 #ifdef CONFIG_COMPAT
357 unsigned int compatsize;
358 #endif
359 unsigned int hooks;
360 unsigned short proto;
361
362 unsigned short family;
363 };
364
365 /* Furniture shopping... */
366 struct xt_table {
367 struct list_head list;
368
369 /* What hooks you will enter on */
370 unsigned int valid_hooks;
371
372 /* Man behind the curtain... */
373 struct xt_table_info *private;
374
375 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
376 struct module *me;
377
378 u_int8_t af; /* address/protocol family */
379 int priority; /* hook order */
380
381 /* A unique name... */
382 const char name[XT_TABLE_MAXNAMELEN];
383 };
384
385 #include <linux/netfilter_ipv4.h>
386
387 /* The table itself */
388 struct xt_table_info {
389 /* Size per table */
390 unsigned int size;
391 /* Number of entries: FIXME. --RR */
392 unsigned int number;
393 /* Initial number of entries. Needed for module usage count */
394 unsigned int initial_entries;
395
396 /* Entry points and underflows */
397 unsigned int hook_entry[NF_INET_NUMHOOKS];
398 unsigned int underflow[NF_INET_NUMHOOKS];
399
400 /*
401 * Number of user chains. Since tables cannot have loops, at most
402 * @stacksize jumps (number of user chains) can possibly be made.
403 */
404 unsigned int stacksize;
405 unsigned int __percpu *stackptr;
406 void ***jumpstack;
407 /* ipt_entry tables: one per CPU */
408 /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
409 void *entries[1];
410 };
411
412 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
413 + nr_cpu_ids * sizeof(char *))
414 extern int xt_register_target(struct xt_target *target);
415 extern void xt_unregister_target(struct xt_target *target);
416 extern int xt_register_targets(struct xt_target *target, unsigned int n);
417 extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
418
419 extern int xt_register_match(struct xt_match *target);
420 extern void xt_unregister_match(struct xt_match *target);
421 extern int xt_register_matches(struct xt_match *match, unsigned int n);
422 extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
423
424 extern int xt_check_match(struct xt_mtchk_param *,
425 unsigned int size, u_int8_t proto, bool inv_proto);
426 extern int xt_check_target(struct xt_tgchk_param *,
427 unsigned int size, u_int8_t proto, bool inv_proto);
428
429 extern struct xt_table *xt_register_table(struct net *net,
430 const struct xt_table *table,
431 struct xt_table_info *bootstrap,
432 struct xt_table_info *newinfo);
433 extern void *xt_unregister_table(struct xt_table *table);
434
435 extern struct xt_table_info *xt_replace_table(struct xt_table *table,
436 unsigned int num_counters,
437 struct xt_table_info *newinfo,
438 int *error);
439
440 extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
441 extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
442 extern struct xt_match *xt_request_find_match(u8 af, const char *name,
443 u8 revision);
444 extern struct xt_target *xt_request_find_target(u8 af, const char *name,
445 u8 revision);
446 extern int xt_find_revision(u8 af, const char *name, u8 revision,
447 int target, int *err);
448
449 extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
450 const char *name);
451 extern void xt_table_unlock(struct xt_table *t);
452
453 extern int xt_proto_init(struct net *net, u_int8_t af);
454 extern void xt_proto_fini(struct net *net, u_int8_t af);
455
456 extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
457 extern void xt_free_table_info(struct xt_table_info *info);
458
459 /**
460 * xt_recseq - recursive seqcount for netfilter use
461 *
462 * Packet processing changes the seqcount only if no recursion happened
463 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
464 * because we use the normal seqcount convention :
465 * Low order bit set to 1 if a writer is active.
466 */
467 DECLARE_PER_CPU(seqcount_t, xt_recseq);
468
469 /**
470 * xt_write_recseq_begin - start of a write section
471 *
472 * Begin packet processing : all readers must wait the end
473 * 1) Must be called with preemption disabled
474 * 2) softirqs must be disabled too (or we should use this_cpu_add())
475 * Returns :
476 * 1 if no recursion on this cpu
477 * 0 if recursion detected
478 */
xt_write_recseq_begin(void)479 static inline unsigned int xt_write_recseq_begin(void)
480 {
481 unsigned int addend;
482
483 /*
484 * Low order bit of sequence is set if we already
485 * called xt_write_recseq_begin().
486 */
487 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
488
489 /*
490 * This is kind of a write_seqcount_begin(), but addend is 0 or 1
491 * We dont check addend value to avoid a test and conditional jump,
492 * since addend is most likely 1
493 */
494 __this_cpu_add(xt_recseq.sequence, addend);
495 smp_wmb();
496
497 return addend;
498 }
499
500 /**
501 * xt_write_recseq_end - end of a write section
502 * @addend: return value from previous xt_write_recseq_begin()
503 *
504 * End packet processing : all readers can proceed
505 * 1) Must be called with preemption disabled
506 * 2) softirqs must be disabled too (or we should use this_cpu_add())
507 */
xt_write_recseq_end(unsigned int addend)508 static inline void xt_write_recseq_end(unsigned int addend)
509 {
510 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
511 smp_wmb();
512 __this_cpu_add(xt_recseq.sequence, addend);
513 }
514
515 /*
516 * This helper is performance critical and must be inlined
517 */
ifname_compare_aligned(const char * _a,const char * _b,const char * _mask)518 static inline unsigned long ifname_compare_aligned(const char *_a,
519 const char *_b,
520 const char *_mask)
521 {
522 const unsigned long *a = (const unsigned long *)_a;
523 const unsigned long *b = (const unsigned long *)_b;
524 const unsigned long *mask = (const unsigned long *)_mask;
525 unsigned long ret;
526
527 ret = (a[0] ^ b[0]) & mask[0];
528 if (IFNAMSIZ > sizeof(unsigned long))
529 ret |= (a[1] ^ b[1]) & mask[1];
530 if (IFNAMSIZ > 2 * sizeof(unsigned long))
531 ret |= (a[2] ^ b[2]) & mask[2];
532 if (IFNAMSIZ > 3 * sizeof(unsigned long))
533 ret |= (a[3] ^ b[3]) & mask[3];
534 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
535 return ret;
536 }
537
538 extern struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *);
539 extern void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *);
540
541 #ifdef CONFIG_COMPAT
542 #include <net/compat.h>
543
544 struct compat_xt_entry_match {
545 union {
546 struct {
547 u_int16_t match_size;
548 char name[XT_FUNCTION_MAXNAMELEN - 1];
549 u_int8_t revision;
550 } user;
551 struct {
552 u_int16_t match_size;
553 compat_uptr_t match;
554 } kernel;
555 u_int16_t match_size;
556 } u;
557 unsigned char data[0];
558 };
559
560 struct compat_xt_entry_target {
561 union {
562 struct {
563 u_int16_t target_size;
564 char name[XT_FUNCTION_MAXNAMELEN - 1];
565 u_int8_t revision;
566 } user;
567 struct {
568 u_int16_t target_size;
569 compat_uptr_t target;
570 } kernel;
571 u_int16_t target_size;
572 } u;
573 unsigned char data[0];
574 };
575
576 /* FIXME: this works only on 32 bit tasks
577 * need to change whole approach in order to calculate align as function of
578 * current task alignment */
579
580 struct compat_xt_counters {
581 compat_u64 pcnt, bcnt; /* Packet and byte counters */
582 };
583
584 struct compat_xt_counters_info {
585 char name[XT_TABLE_MAXNAMELEN];
586 compat_uint_t num_counters;
587 struct compat_xt_counters counters[0];
588 };
589
590 struct _compat_xt_align {
591 __u8 u8;
592 __u16 u16;
593 __u32 u32;
594 compat_u64 u64;
595 };
596
597 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
598
599 extern void xt_compat_lock(u_int8_t af);
600 extern void xt_compat_unlock(u_int8_t af);
601
602 extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
603 extern void xt_compat_flush_offsets(u_int8_t af);
604 extern void xt_compat_init_offsets(u_int8_t af, unsigned int number);
605 extern int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
606
607 extern int xt_compat_match_offset(const struct xt_match *match);
608 extern int xt_compat_match_from_user(struct xt_entry_match *m,
609 void **dstptr, unsigned int *size);
610 extern int xt_compat_match_to_user(const struct xt_entry_match *m,
611 void __user **dstptr, unsigned int *size);
612
613 extern int xt_compat_target_offset(const struct xt_target *target);
614 extern void xt_compat_target_from_user(struct xt_entry_target *t,
615 void **dstptr, unsigned int *size);
616 extern int xt_compat_target_to_user(const struct xt_entry_target *t,
617 void __user **dstptr, unsigned int *size);
618
619 #endif /* CONFIG_COMPAT */
620 #endif /* __KERNEL__ */
621
622 #endif /* _X_TABLES_H */
623