5 #include <linux/netdevice.h>
6 #include <linux/static_key.h>
7 #include <linux/locallock.h>
8 #include <uapi/linux/netfilter/x_tables.h>
11 * struct xt_action_param - parameters for matches/targets
13 * @match: the match extension
14 * @target: the target extension
15 * @matchinfo: per-match data
16 * @targetinfo: per-target data
17 * @net network namespace through which the action was invoked
18 * @in: input netdevice
19 * @out: output netdevice
20 * @fragoff: packet is a fragment, this is the data offset
21 * @thoff: position of transport header relative to skb->data
22 * @hook: hook number given packet came from
23 * @family: Actual NFPROTO_* through which the function is invoked
24 * (helpful when match->family == NFPROTO_UNSPEC)
26 * Fields written to by extensions:
28 * @hotdrop: drop packet if we had inspection problems
30 struct xt_action_param {
32 const struct xt_match *match;
33 const struct xt_target *target;
36 const void *matchinfo, *targinfo;
39 const struct net_device *in, *out;
48 * struct xt_mtchk_param - parameters for match extensions'
49 * checkentry functions
51 * @net: network namespace through which the check was invoked
52 * @table: table the rule is tried to be inserted into
53 * @entryinfo: the family-specific rule data
54 * (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry)
55 * @match: struct xt_match through which this function was invoked
56 * @matchinfo: per-match data
57 * @hook_mask: via which hooks the new rule is reachable
58 * Other fields as above.
60 struct xt_mtchk_param {
63 const void *entryinfo;
64 const struct xt_match *match;
66 unsigned int hook_mask;
72 * struct xt_mdtor_param - match destructor parameters
75 struct xt_mtdtor_param {
77 const struct xt_match *match;
83 * struct xt_tgchk_param - parameters for target extensions'
84 * checkentry functions
86 * @entryinfo: the family-specific rule data
87 * (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
89 * Other fields see above.
91 struct xt_tgchk_param {
94 const void *entryinfo;
95 const struct xt_target *target;
97 unsigned int hook_mask;
102 /* Target destructor parameters */
103 struct xt_tgdtor_param {
105 const struct xt_target *target;
111 struct list_head list;
113 const char name[XT_EXTENSION_MAXNAMELEN];
116 /* Return true or false: return FALSE and set *hotdrop = 1 to
117 force immediate packet drop. */
118 /* Arguments changed since 2.6.9, as this must now handle
119 non-linear skb, using skb_header_pointer and
120 skb_ip_make_writable. */
121 bool (*match)(const struct sk_buff *skb,
122 struct xt_action_param *);
124 /* Called when user tries to insert an entry of this type. */
125 int (*checkentry)(const struct xt_mtchk_param *);
127 /* Called when entry of this type deleted. */
128 void (*destroy)(const struct xt_mtdtor_param *);
130 /* Called when userspace align differs from kernel space one */
131 void (*compat_from_user)(void *dst, const void *src);
132 int (*compat_to_user)(void __user *dst, const void *src);
134 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
138 unsigned int matchsize;
140 unsigned int compatsize;
143 unsigned short proto;
145 unsigned short family;
148 /* Registration hooks for targets. */
150 struct list_head list;
152 const char name[XT_EXTENSION_MAXNAMELEN];
155 /* Returns verdict. Argument order changed since 2.6.9, as this
156 must now handle non-linear skbs, using skb_copy_bits and
157 skb_ip_make_writable. */
158 unsigned int (*target)(struct sk_buff *skb,
159 const struct xt_action_param *);
161 /* Called when user tries to insert an entry of this type:
162 hook_mask is a bitmask of hooks from which it can be
164 /* Should return 0 on success or an error code otherwise (-Exxxx). */
165 int (*checkentry)(const struct xt_tgchk_param *);
167 /* Called when entry of this type deleted. */
168 void (*destroy)(const struct xt_tgdtor_param *);
170 /* Called when userspace align differs from kernel space one */
171 void (*compat_from_user)(void *dst, const void *src);
172 int (*compat_to_user)(void __user *dst, const void *src);
174 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
178 unsigned int targetsize;
180 unsigned int compatsize;
183 unsigned short proto;
185 unsigned short family;
188 /* Furniture shopping... */
190 struct list_head list;
192 /* What hooks you will enter on */
193 unsigned int valid_hooks;
195 /* Man behind the curtain... */
196 struct xt_table_info *private;
198 /* Set this to THIS_MODULE if you are a module, otherwise NULL */
201 u_int8_t af; /* address/protocol family */
202 int priority; /* hook order */
204 /* A unique name... */
205 const char name[XT_TABLE_MAXNAMELEN];
208 #include <linux/netfilter_ipv4.h>
210 /* The table itself */
211 struct xt_table_info {
214 /* Number of entries: FIXME. --RR */
216 /* Initial number of entries. Needed for module usage count */
217 unsigned int initial_entries;
219 /* Entry points and underflows */
220 unsigned int hook_entry[NF_INET_NUMHOOKS];
221 unsigned int underflow[NF_INET_NUMHOOKS];
224 * Number of user chains. Since tables cannot have loops, at most
225 * @stacksize jumps (number of user chains) can possibly be made.
227 unsigned int stacksize;
230 unsigned char entries[0] __aligned(8);
233 int xt_register_target(struct xt_target *target);
234 void xt_unregister_target(struct xt_target *target);
235 int xt_register_targets(struct xt_target *target, unsigned int n);
236 void xt_unregister_targets(struct xt_target *target, unsigned int n);
238 int xt_register_match(struct xt_match *target);
239 void xt_unregister_match(struct xt_match *target);
240 int xt_register_matches(struct xt_match *match, unsigned int n);
241 void xt_unregister_matches(struct xt_match *match, unsigned int n);
243 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
245 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
248 struct xt_table *xt_register_table(struct net *net,
249 const struct xt_table *table,
250 struct xt_table_info *bootstrap,
251 struct xt_table_info *newinfo);
252 void *xt_unregister_table(struct xt_table *table);
254 struct xt_table_info *xt_replace_table(struct xt_table *table,
255 unsigned int num_counters,
256 struct xt_table_info *newinfo,
259 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
260 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
261 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision);
262 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision);
263 int xt_find_revision(u8 af, const char *name, u8 revision, int target,
266 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
268 void xt_table_unlock(struct xt_table *t);
270 int xt_proto_init(struct net *net, u_int8_t af);
271 void xt_proto_fini(struct net *net, u_int8_t af);
273 struct xt_table_info *xt_alloc_table_info(unsigned int size);
274 void xt_free_table_info(struct xt_table_info *info);
277 * xt_recseq - recursive seqcount for netfilter use
279 * Packet processing changes the seqcount only if no recursion happened
280 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
281 * because we use the normal seqcount convention :
282 * Low order bit set to 1 if a writer is active.
284 DECLARE_PER_CPU(seqcount_t, xt_recseq);
286 DECLARE_LOCAL_IRQ_LOCK(xt_write_lock);
288 /* xt_tee_enabled - true if x_tables needs to handle reentrancy
290 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
292 extern struct static_key xt_tee_enabled;
295 * xt_write_recseq_begin - start of a write section
297 * Begin packet processing : all readers must wait the end
298 * 1) Must be called with preemption disabled
299 * 2) softirqs must be disabled too (or we should use this_cpu_add())
301 * 1 if no recursion on this cpu
302 * 0 if recursion detected
304 static inline unsigned int xt_write_recseq_begin(void)
309 local_lock(xt_write_lock);
312 * Low order bit of sequence is set if we already
313 * called xt_write_recseq_begin().
315 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
318 * This is kind of a write_seqcount_begin(), but addend is 0 or 1
319 * We dont check addend value to avoid a test and conditional jump,
320 * since addend is most likely 1
322 __this_cpu_add(xt_recseq.sequence, addend);
329 * xt_write_recseq_end - end of a write section
330 * @addend: return value from previous xt_write_recseq_begin()
332 * End packet processing : all readers can proceed
333 * 1) Must be called with preemption disabled
334 * 2) softirqs must be disabled too (or we should use this_cpu_add())
336 static inline void xt_write_recseq_end(unsigned int addend)
338 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
340 __this_cpu_add(xt_recseq.sequence, addend);
341 local_unlock(xt_write_lock);
345 * This helper is performance critical and must be inlined
347 static inline unsigned long ifname_compare_aligned(const char *_a,
351 const unsigned long *a = (const unsigned long *)_a;
352 const unsigned long *b = (const unsigned long *)_b;
353 const unsigned long *mask = (const unsigned long *)_mask;
356 ret = (a[0] ^ b[0]) & mask[0];
357 if (IFNAMSIZ > sizeof(unsigned long))
358 ret |= (a[1] ^ b[1]) & mask[1];
359 if (IFNAMSIZ > 2 * sizeof(unsigned long))
360 ret |= (a[2] ^ b[2]) & mask[2];
361 if (IFNAMSIZ > 3 * sizeof(unsigned long))
362 ret |= (a[3] ^ b[3]) & mask[3];
363 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
368 /* On SMP, ip(6)t_entry->counters.pcnt holds address of the
369 * real (percpu) counter. On !SMP, its just the packet count,
370 * so nothing needs to be done there.
372 * xt_percpu_counter_alloc returns the address of the percpu
373 * counter, or 0 on !SMP. We force an alignment of 16 bytes
374 * so that bytes/packets share a common cache line.
376 * Hence caller must use IS_ERR_VALUE to check for error, this
377 * allows us to return 0 for single core systems without forcing
378 * callers to deal with SMP vs. NONSMP issues.
380 static inline u64 xt_percpu_counter_alloc(void)
382 if (nr_cpu_ids > 1) {
383 void __percpu *res = __alloc_percpu(sizeof(struct xt_counters),
384 sizeof(struct xt_counters));
387 return (u64) -ENOMEM;
389 return (u64) (__force unsigned long) res;
394 static inline void xt_percpu_counter_free(u64 pcnt)
397 free_percpu((void __percpu *) (unsigned long) pcnt);
400 static inline struct xt_counters *
401 xt_get_this_cpu_counter(struct xt_counters *cnt)
404 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt);
409 static inline struct xt_counters *
410 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
413 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu);
418 struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *);
419 void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *);
422 #include <net/compat.h>
424 struct compat_xt_entry_match {
427 u_int16_t match_size;
428 char name[XT_FUNCTION_MAXNAMELEN - 1];
432 u_int16_t match_size;
435 u_int16_t match_size;
437 unsigned char data[0];
440 struct compat_xt_entry_target {
443 u_int16_t target_size;
444 char name[XT_FUNCTION_MAXNAMELEN - 1];
448 u_int16_t target_size;
449 compat_uptr_t target;
451 u_int16_t target_size;
453 unsigned char data[0];
456 /* FIXME: this works only on 32 bit tasks
457 * need to change whole approach in order to calculate align as function of
458 * current task alignment */
460 struct compat_xt_counters {
461 compat_u64 pcnt, bcnt; /* Packet and byte counters */
464 struct compat_xt_counters_info {
465 char name[XT_TABLE_MAXNAMELEN];
466 compat_uint_t num_counters;
467 struct compat_xt_counters counters[0];
470 struct _compat_xt_align {
477 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
479 void xt_compat_lock(u_int8_t af);
480 void xt_compat_unlock(u_int8_t af);
482 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
483 void xt_compat_flush_offsets(u_int8_t af);
484 void xt_compat_init_offsets(u_int8_t af, unsigned int number);
485 int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
487 int xt_compat_match_offset(const struct xt_match *match);
488 int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
490 int xt_compat_match_to_user(const struct xt_entry_match *m,
491 void __user **dstptr, unsigned int *size);
493 int xt_compat_target_offset(const struct xt_target *target);
494 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
496 int xt_compat_target_to_user(const struct xt_entry_target *t,
497 void __user **dstptr, unsigned int *size);
499 #endif /* CONFIG_COMPAT */
500 #endif /* _X_TABLES_H */