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