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