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TOMOYO Linux Cross Reference
Linux/include/linux/netfilter/x_tables.h

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  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 <linux/netfilter.h>
  8 #include <uapi/linux/netfilter/x_tables.h>
  9 
 10 /* Test a struct->invflags and a boolean for inequality */
 11 #define NF_INVF(ptr, flag, boolean)                                     \
 12         ((boolean) ^ !!((ptr)->invflags & (flag)))
 13 
 14 /**
 15  * struct xt_action_param - parameters for matches/targets
 16  *
 17  * @match:      the match extension
 18  * @target:     the target extension
 19  * @matchinfo:  per-match data
 20  * @targetinfo: per-target data
 21  * @state:      pointer to hook state this packet came from
 22  * @fragoff:    packet is a fragment, this is the data offset
 23  * @thoff:      position of transport header relative to skb->data
 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         const struct nf_hook_state *state;
 38         int fragoff;
 39         unsigned int thoff;
 40         bool hotdrop;
 41 };
 42 
 43 static inline struct net *xt_net(const struct xt_action_param *par)
 44 {
 45         return par->state->net;
 46 }
 47 
 48 static inline struct net_device *xt_in(const struct xt_action_param *par)
 49 {
 50         return par->state->in;
 51 }
 52 
 53 static inline const char *xt_inname(const struct xt_action_param *par)
 54 {
 55         return par->state->in->name;
 56 }
 57 
 58 static inline struct net_device *xt_out(const struct xt_action_param *par)
 59 {
 60         return par->state->out;
 61 }
 62 
 63 static inline const char *xt_outname(const struct xt_action_param *par)
 64 {
 65         return par->state->out->name;
 66 }
 67 
 68 static inline unsigned int xt_hooknum(const struct xt_action_param *par)
 69 {
 70         return par->state->hook;
 71 }
 72 
 73 static inline u_int8_t xt_family(const struct xt_action_param *par)
 74 {
 75         return par->state->pf;
 76 }
 77 
 78 /**
 79  * struct xt_mtchk_param - parameters for match extensions'
 80  * checkentry functions
 81  *
 82  * @net:        network namespace through which the check was invoked
 83  * @table:      table the rule is tried to be inserted into
 84  * @entryinfo:  the family-specific rule data
 85  *              (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry)
 86  * @match:      struct xt_match through which this function was invoked
 87  * @matchinfo:  per-match data
 88  * @hook_mask:  via which hooks the new rule is reachable
 89  * Other fields as above.
 90  */
 91 struct xt_mtchk_param {
 92         struct net *net;
 93         const char *table;
 94         const void *entryinfo;
 95         const struct xt_match *match;
 96         void *matchinfo;
 97         unsigned int hook_mask;
 98         u_int8_t family;
 99         bool nft_compat;
100 };
101 
102 /**
103  * struct xt_mdtor_param - match destructor parameters
104  * Fields as above.
105  */
106 struct xt_mtdtor_param {
107         struct net *net;
108         const struct xt_match *match;
109         void *matchinfo;
110         u_int8_t family;
111 };
112 
113 /**
114  * struct xt_tgchk_param - parameters for target extensions'
115  * checkentry functions
116  *
117  * @entryinfo:  the family-specific rule data
118  *              (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
119  *
120  * Other fields see above.
121  */
122 struct xt_tgchk_param {
123         struct net *net;
124         const char *table;
125         const void *entryinfo;
126         const struct xt_target *target;
127         void *targinfo;
128         unsigned int hook_mask;
129         u_int8_t family;
130         bool nft_compat;
131 };
132 
133 /* Target destructor parameters */
134 struct xt_tgdtor_param {
135         struct net *net;
136         const struct xt_target *target;
137         void *targinfo;
138         u_int8_t family;
139 };
140 
141 struct xt_match {
142         struct list_head list;
143 
144         const char name[XT_EXTENSION_MAXNAMELEN];
145         u_int8_t revision;
146 
147         /* Return true or false: return FALSE and set *hotdrop = 1 to
148            force immediate packet drop. */
149         /* Arguments changed since 2.6.9, as this must now handle
150            non-linear skb, using skb_header_pointer and
151            skb_ip_make_writable. */
152         bool (*match)(const struct sk_buff *skb,
153                       struct xt_action_param *);
154 
155         /* Called when user tries to insert an entry of this type. */
156         int (*checkentry)(const struct xt_mtchk_param *);
157 
158         /* Called when entry of this type deleted. */
159         void (*destroy)(const struct xt_mtdtor_param *);
160 #ifdef CONFIG_COMPAT
161         /* Called when userspace align differs from kernel space one */
162         void (*compat_from_user)(void *dst, const void *src);
163         int (*compat_to_user)(void __user *dst, const void *src);
164 #endif
165         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
166         struct module *me;
167 
168         const char *table;
169         unsigned int matchsize;
170         unsigned int usersize;
171 #ifdef CONFIG_COMPAT
172         unsigned int compatsize;
173 #endif
174         unsigned int hooks;
175         unsigned short proto;
176 
177         unsigned short family;
178 };
179 
180 /* Registration hooks for targets. */
181 struct xt_target {
182         struct list_head list;
183 
184         const char name[XT_EXTENSION_MAXNAMELEN];
185         u_int8_t revision;
186 
187         /* Returns verdict. Argument order changed since 2.6.9, as this
188            must now handle non-linear skbs, using skb_copy_bits and
189            skb_ip_make_writable. */
190         unsigned int (*target)(struct sk_buff *skb,
191                                const struct xt_action_param *);
192 
193         /* Called when user tries to insert an entry of this type:
194            hook_mask is a bitmask of hooks from which it can be
195            called. */
196         /* Should return 0 on success or an error code otherwise (-Exxxx). */
197         int (*checkentry)(const struct xt_tgchk_param *);
198 
199         /* Called when entry of this type deleted. */
200         void (*destroy)(const struct xt_tgdtor_param *);
201 #ifdef CONFIG_COMPAT
202         /* Called when userspace align differs from kernel space one */
203         void (*compat_from_user)(void *dst, const void *src);
204         int (*compat_to_user)(void __user *dst, const void *src);
205 #endif
206         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
207         struct module *me;
208 
209         const char *table;
210         unsigned int targetsize;
211         unsigned int usersize;
212 #ifdef CONFIG_COMPAT
213         unsigned int compatsize;
214 #endif
215         unsigned int hooks;
216         unsigned short proto;
217 
218         unsigned short family;
219 };
220 
221 /* Furniture shopping... */
222 struct xt_table {
223         struct list_head list;
224 
225         /* What hooks you will enter on */
226         unsigned int valid_hooks;
227 
228         /* Man behind the curtain... */
229         struct xt_table_info *private;
230 
231         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
232         struct module *me;
233 
234         u_int8_t af;            /* address/protocol family */
235         int priority;           /* hook order */
236 
237         /* called when table is needed in the given netns */
238         int (*table_init)(struct net *net);
239 
240         /* A unique name... */
241         const char name[XT_TABLE_MAXNAMELEN];
242 };
243 
244 #include <linux/netfilter_ipv4.h>
245 
246 /* The table itself */
247 struct xt_table_info {
248         /* Size per table */
249         unsigned int size;
250         /* Number of entries: FIXME. --RR */
251         unsigned int number;
252         /* Initial number of entries. Needed for module usage count */
253         unsigned int initial_entries;
254 
255         /* Entry points and underflows */
256         unsigned int hook_entry[NF_INET_NUMHOOKS];
257         unsigned int underflow[NF_INET_NUMHOOKS];
258 
259         /*
260          * Number of user chains. Since tables cannot have loops, at most
261          * @stacksize jumps (number of user chains) can possibly be made.
262          */
263         unsigned int stacksize;
264         void ***jumpstack;
265 
266         unsigned char entries[0] __aligned(8);
267 };
268 
269 int xt_register_target(struct xt_target *target);
270 void xt_unregister_target(struct xt_target *target);
271 int xt_register_targets(struct xt_target *target, unsigned int n);
272 void xt_unregister_targets(struct xt_target *target, unsigned int n);
273 
274 int xt_register_match(struct xt_match *target);
275 void xt_unregister_match(struct xt_match *target);
276 int xt_register_matches(struct xt_match *match, unsigned int n);
277 void xt_unregister_matches(struct xt_match *match, unsigned int n);
278 
279 int xt_check_entry_offsets(const void *base, const char *elems,
280                            unsigned int target_offset,
281                            unsigned int next_offset);
282 
283 unsigned int *xt_alloc_entry_offsets(unsigned int size);
284 bool xt_find_jump_offset(const unsigned int *offsets,
285                          unsigned int target, unsigned int size);
286 
287 int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto,
288                    bool inv_proto);
289 int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
290                     bool inv_proto);
291 
292 int xt_match_to_user(const struct xt_entry_match *m,
293                      struct xt_entry_match __user *u);
294 int xt_target_to_user(const struct xt_entry_target *t,
295                       struct xt_entry_target __user *u);
296 int xt_data_to_user(void __user *dst, const void *src,
297                     int usersize, int size, int aligned_size);
298 
299 void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
300                                  struct xt_counters_info *info, bool compat);
301 
302 struct xt_table *xt_register_table(struct net *net,
303                                    const struct xt_table *table,
304                                    struct xt_table_info *bootstrap,
305                                    struct xt_table_info *newinfo);
306 void *xt_unregister_table(struct xt_table *table);
307 
308 struct xt_table_info *xt_replace_table(struct xt_table *table,
309                                        unsigned int num_counters,
310                                        struct xt_table_info *newinfo,
311                                        int *error);
312 
313 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
314 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
315 struct xt_match *xt_request_find_match(u8 af, const char *name, u8 revision);
316 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision);
317 int xt_find_revision(u8 af, const char *name, u8 revision, int target,
318                      int *err);
319 
320 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
321                                     const char *name);
322 void xt_table_unlock(struct xt_table *t);
323 
324 int xt_proto_init(struct net *net, u_int8_t af);
325 void xt_proto_fini(struct net *net, u_int8_t af);
326 
327 struct xt_table_info *xt_alloc_table_info(unsigned int size);
328 void xt_free_table_info(struct xt_table_info *info);
329 
330 /**
331  * xt_recseq - recursive seqcount for netfilter use
332  * 
333  * Packet processing changes the seqcount only if no recursion happened
334  * get_counters() can use read_seqcount_begin()/read_seqcount_retry(),
335  * because we use the normal seqcount convention :
336  * Low order bit set to 1 if a writer is active.
337  */
338 DECLARE_PER_CPU(seqcount_t, xt_recseq);
339 
340 /* xt_tee_enabled - true if x_tables needs to handle reentrancy
341  *
342  * Enabled if current ip(6)tables ruleset has at least one -j TEE rule.
343  */
344 extern struct static_key xt_tee_enabled;
345 
346 /**
347  * xt_write_recseq_begin - start of a write section
348  *
349  * Begin packet processing : all readers must wait the end
350  * 1) Must be called with preemption disabled
351  * 2) softirqs must be disabled too (or we should use this_cpu_add())
352  * Returns :
353  *  1 if no recursion on this cpu
354  *  0 if recursion detected
355  */
356 static inline unsigned int xt_write_recseq_begin(void)
357 {
358         unsigned int addend;
359 
360         /*
361          * Low order bit of sequence is set if we already
362          * called xt_write_recseq_begin().
363          */
364         addend = (__this_cpu_read(xt_recseq.sequence) + 1) & 1;
365 
366         /*
367          * This is kind of a write_seqcount_begin(), but addend is 0 or 1
368          * We dont check addend value to avoid a test and conditional jump,
369          * since addend is most likely 1
370          */
371         __this_cpu_add(xt_recseq.sequence, addend);
372         smp_wmb();
373 
374         return addend;
375 }
376 
377 /**
378  * xt_write_recseq_end - end of a write section
379  * @addend: return value from previous xt_write_recseq_begin()
380  *
381  * End packet processing : all readers can proceed
382  * 1) Must be called with preemption disabled
383  * 2) softirqs must be disabled too (or we should use this_cpu_add())
384  */
385 static inline void xt_write_recseq_end(unsigned int addend)
386 {
387         /* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
388         smp_wmb();
389         __this_cpu_add(xt_recseq.sequence, addend);
390 }
391 
392 /*
393  * This helper is performance critical and must be inlined
394  */
395 static inline unsigned long ifname_compare_aligned(const char *_a,
396                                                    const char *_b,
397                                                    const char *_mask)
398 {
399         const unsigned long *a = (const unsigned long *)_a;
400         const unsigned long *b = (const unsigned long *)_b;
401         const unsigned long *mask = (const unsigned long *)_mask;
402         unsigned long ret;
403 
404         ret = (a[0] ^ b[0]) & mask[0];
405         if (IFNAMSIZ > sizeof(unsigned long))
406                 ret |= (a[1] ^ b[1]) & mask[1];
407         if (IFNAMSIZ > 2 * sizeof(unsigned long))
408                 ret |= (a[2] ^ b[2]) & mask[2];
409         if (IFNAMSIZ > 3 * sizeof(unsigned long))
410                 ret |= (a[3] ^ b[3]) & mask[3];
411         BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
412         return ret;
413 }
414 
415 struct xt_percpu_counter_alloc_state {
416         unsigned int off;
417         const char __percpu *mem;
418 };
419 
420 bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state,
421                              struct xt_counters *counter);
422 void xt_percpu_counter_free(struct xt_counters *cnt);
423 
424 static inline struct xt_counters *
425 xt_get_this_cpu_counter(struct xt_counters *cnt)
426 {
427         if (nr_cpu_ids > 1)
428                 return this_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt);
429 
430         return cnt;
431 }
432 
433 static inline struct xt_counters *
434 xt_get_per_cpu_counter(struct xt_counters *cnt, unsigned int cpu)
435 {
436         if (nr_cpu_ids > 1)
437                 return per_cpu_ptr((void __percpu *) (unsigned long) cnt->pcnt, cpu);
438 
439         return cnt;
440 }
441 
442 struct nf_hook_ops *xt_hook_ops_alloc(const struct xt_table *, nf_hookfn *);
443 
444 #ifdef CONFIG_COMPAT
445 #include <net/compat.h>
446 
447 struct compat_xt_entry_match {
448         union {
449                 struct {
450                         u_int16_t match_size;
451                         char name[XT_FUNCTION_MAXNAMELEN - 1];
452                         u_int8_t revision;
453                 } user;
454                 struct {
455                         u_int16_t match_size;
456                         compat_uptr_t match;
457                 } kernel;
458                 u_int16_t match_size;
459         } u;
460         unsigned char data[0];
461 };
462 
463 struct compat_xt_entry_target {
464         union {
465                 struct {
466                         u_int16_t target_size;
467                         char name[XT_FUNCTION_MAXNAMELEN - 1];
468                         u_int8_t revision;
469                 } user;
470                 struct {
471                         u_int16_t target_size;
472                         compat_uptr_t target;
473                 } kernel;
474                 u_int16_t target_size;
475         } u;
476         unsigned char data[0];
477 };
478 
479 /* FIXME: this works only on 32 bit tasks
480  * need to change whole approach in order to calculate align as function of
481  * current task alignment */
482 
483 struct compat_xt_counters {
484         compat_u64 pcnt, bcnt;                  /* Packet and byte counters */
485 };
486 
487 struct compat_xt_counters_info {
488         char name[XT_TABLE_MAXNAMELEN];
489         compat_uint_t num_counters;
490         struct compat_xt_counters counters[0];
491 };
492 
493 struct _compat_xt_align {
494         __u8 u8;
495         __u16 u16;
496         __u32 u32;
497         compat_u64 u64;
498 };
499 
500 #define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))
501 
502 void xt_compat_lock(u_int8_t af);
503 void xt_compat_unlock(u_int8_t af);
504 
505 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
506 void xt_compat_flush_offsets(u_int8_t af);
507 void xt_compat_init_offsets(u_int8_t af, unsigned int number);
508 int xt_compat_calc_jump(u_int8_t af, unsigned int offset);
509 
510 int xt_compat_match_offset(const struct xt_match *match);
511 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
512                               unsigned int *size);
513 int xt_compat_match_to_user(const struct xt_entry_match *m,
514                             void __user **dstptr, unsigned int *size);
515 
516 int xt_compat_target_offset(const struct xt_target *target);
517 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
518                                 unsigned int *size);
519 int xt_compat_target_to_user(const struct xt_entry_target *t,
520                              void __user **dstptr, unsigned int *size);
521 int xt_compat_check_entry_offsets(const void *base, const char *elems,
522                                   unsigned int target_offset,
523                                   unsigned int next_offset);
524 
525 #endif /* CONFIG_COMPAT */
526 #endif /* _X_TABLES_H */
527 

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