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_entry_offsets(const void *base, const char *elems,
244 unsigned int target_offset,
245 unsigned int next_offset);
247 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
249 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
252 void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
253 struct xt_counters_info *info, bool compat);
255 struct xt_table *xt_register_table(struct net *net,
256 const struct xt_table *table,
257 struct xt_table_info *bootstrap,
258 struct xt_table_info *newinfo);
259 void *xt_unregister_table(struct xt_table *table);
261 struct xt_table_info *xt_replace_table(struct xt_table *table,
262 unsigned int num_counters,
263 struct xt_table_info *newinfo,
266 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
267 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
268 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision);
269 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision);
270 int xt_find_revision(u8 af, const char *name, u8 revision, int target,
273 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
275 void xt_table_unlock(struct xt_table *t);
277 int xt_proto_init(struct net *net, u_int8_t af);
278 void xt_proto_fini(struct net *net, u_int8_t af);
280 struct xt_table_info *xt_alloc_table_info(unsigned int size);
281 void xt_free_table_info(struct xt_table_info *info);
284 * xt_recseq - recursive seqcount for netfilter use
286 * Packet processing changes the seqcount only if no recursion happened
287 * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
288 * because we use the normal seqcount convention :
289 * Low order bit set to 1 if a writer is active.
291 DECLARE_PER_CPU(seqcount_t, xt_recseq);
293 DECLARE_LOCAL_IRQ_LOCK(xt_write_lock);
295 /* xt_tee_enabled - true if x_tables needs to handle reentrancy
297 * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
299 extern struct static_key xt_tee_enabled;
302 * xt_write_recseq_begin - start of a write section
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())
308 * 1 if no recursion on this cpu
309 * 0 if recursion detected
311 static inline unsigned int xt_write_recseq_begin(void)
316 local_lock(xt_write_lock);
319 * Low order bit of sequence is set if we already
320 * called xt_write_recseq_begin().
322 addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
325 * This is kind of a write_seqcount_begin(), but addend is 0 or 1
326 * We dont check addend value to avoid a test and conditional jump,
327 * since addend is most likely 1
329 __this_cpu_add(xt_recseq.sequence, addend);
336 * xt_write_recseq_end - end of a write section
337 * @addend: return value from previous xt_write_recseq_begin()
339 * End packet processing : all readers can proceed
340 * 1) Must be called with preemption disabled
341 * 2) softirqs must be disabled too (or we should use this_cpu_add())
343 static inline void xt_write_recseq_end(unsigned int addend)
345 /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
347 __this_cpu_add(xt_recseq.sequence, addend);
348 local_unlock(xt_write_lock);
352 * This helper is performance critical and must be inlined
354 static inline unsigned long ifname_compare_aligned(const char *_a,
358 const unsigned long *a = (const unsigned long *)_a;
359 const unsigned long *b = (const unsigned long *)_b;
360 const unsigned long *mask = (const unsigned long *)_mask;
363 ret = (a[0] ^ b[0]) & mask[0];
364 if (IFNAMSIZ > sizeof(unsigned long))
365 ret |= (a[1] ^ b[1]) & mask[1];
366 if (IFNAMSIZ > 2 * sizeof(unsigned long))
367 ret |= (a[2] ^ b[2]) & mask[2];
368 if (IFNAMSIZ > 3 * sizeof(unsigned long))
369 ret |= (a[3] ^ b[3]) & mask[3];
370 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
375 /* On SMP, ip(6)t_entry->counters.pcnt holds address of the
376 * real (percpu) counter. On !SMP, its just the packet count,
377 * so nothing needs to be done there.
379 * xt_percpu_counter_alloc returns the address of the percpu
380 * counter, or 0 on !SMP. We force an alignment of 16 bytes
381 * so that bytes/packets share a common cache line.
383 * Hence caller must use IS_ERR_VALUE to check for error, this
384 * allows us to return 0 for single core systems without forcing
385 * callers to deal with SMP vs. NONSMP issues.
387 static inline u64 xt_percpu_counter_alloc(void)
389 if (nr_cpu_ids > 1) {
390 void __percpu *res = __alloc_percpu(sizeof(struct xt_counters),
391 sizeof(struct xt_counters));
394 return (u64) -ENOMEM;
396 return (u64) (__force unsigned long) res;
401 static inline void xt_percpu_counter_free(u64 pcnt)
404 free_percpu((void __percpu *) (unsigned long) pcnt);
407 static inline struct xt_counters *
408 xt_get_this_cpu_counter(struct xt_counters *cnt)
411 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt);
416 static inline struct xt_counters *
417 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
420 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu);
425 struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *);
426 void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *);
429 #include <net/compat.h>
431 struct compat_xt_entry_match {
434 u_int16_t match_size;
435 char name[XT_FUNCTION_MAXNAMELEN - 1];
439 u_int16_t match_size;
442 u_int16_t match_size;
444 unsigned char data[0];
447 struct compat_xt_entry_target {
450 u_int16_t target_size;
451 char name[XT_FUNCTION_MAXNAMELEN - 1];
455 u_int16_t target_size;
456 compat_uptr_t target;
458 u_int16_t target_size;
460 unsigned char data[0];
463 /* FIXME: this works only on 32 bit tasks
464 * need to change whole approach in order to calculate align as function of
465 * current task alignment */
467 struct compat_xt_counters {
468 compat_u64 pcnt, bcnt; /* Packet and byte counters */
471 struct compat_xt_counters_info {
472 char name[XT_TABLE_MAXNAMELEN];
473 compat_uint_t num_counters;
474 struct compat_xt_counters counters[0];
477 struct _compat_xt_align {
484 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
486 void xt_compat_lock(u_int8_t af);
487 void xt_compat_unlock(u_int8_t af);
489 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
490 void xt_compat_flush_offsets(u_int8_t af);
491 void xt_compat_init_offsets(u_int8_t af, unsigned int number);
492 int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
494 int xt_compat_match_offset(const struct xt_match *match);
495 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
497 int xt_compat_match_to_user(const struct xt_entry_match *m,
498 void __user **dstptr, unsigned int *size);
500 int xt_compat_target_offset(const struct xt_target *target);
501 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
503 int xt_compat_target_to_user(const struct xt_entry_target *t,
504 void __user **dstptr, unsigned int *size);
505 int xt_compat_check_entry_offsets(const void *base, const char *elems,
506 unsigned int target_offset,
507 unsigned int next_offset);
509 #endif /* CONFIG_COMPAT */
510 #endif /* _X_TABLES_H */