release/src-rt-6.x/linux/linux-2.6/include/linux/netfilter/x_tables.h

   1 #ifndef _X_TABLES_H
   2 #define _X_TABLES_H
   3
   4 #define XT_FUNCTION_MAXNAMELEN 30
   5 #define XT_TABLE_MAXNAMELEN 32
   6
   7 struct xt_entry_match
   8 {
   9         union {
  10                 struct {
  11                         u_int16_t match_size;
  12
  13                         /* Used by userspace */
  14                         char name[XT_FUNCTION_MAXNAMELEN-1];
  15
  16                         u_int8_t revision;
  17                 } user;
  18                 struct {
  19                         u_int16_t match_size;
  20
  21                         /* Used inside the kernel */
  22                         struct xt_match *match;
  23                 } kernel;
  24
  25                 /* Total length */
  26                 u_int16_t match_size;
  27         } u;
  28
  29         unsigned char data[0];
  30 };
  31
  32 struct xt_entry_target
  33 {
  34         union {
  35                 struct {
  36                         u_int16_t target_size;
  37
  38                         /* Used by userspace */
  39                         char name[XT_FUNCTION_MAXNAMELEN-1];
  40
  41                         u_int8_t revision;
  42                 } user;
  43                 struct {
  44                         u_int16_t target_size;
  45
  46                         /* Used inside the kernel */
  47                         struct xt_target *target;
  48                 } kernel;
  49
  50                 /* Total length */
  51                 u_int16_t target_size;
  52         } u;
  53
  54         unsigned char data[0];
  55 };
  56
  57 #define XT_TARGET_INIT(__name, __size)                                         \
  58 {                                                                              \
  59         .target.u.user = {                                                     \
  60                 .target_size    = XT_ALIGN(__size),                            \
  61                 .name           = __name,                                      \
  62         },                                                                     \
  63 }
  64
  65 struct xt_standard_target
  66 {
  67         struct xt_entry_target target;
  68         int verdict;
  69 };
  70
  71 /* The argument to IPT_SO_GET_REVISION_*.  Returns highest revision
  72  * kernel supports, if >= revision. */
  73 struct xt_get_revision
  74 {
  75         char name[XT_FUNCTION_MAXNAMELEN-1];
  76
  77         u_int8_t revision;
  78 };
  79
  80 /* CONTINUE verdict for targets */
  81 #define XT_CONTINUE 0xFFFFFFFF
  82
  83 /* For standard target */
  84 #define XT_RETURN (-NF_REPEAT - 1)
  85
  86 /* this is a dummy structure to find out the alignment requirement for a struct
  87  * containing all the fundamental data types that are used in ipt_entry,
  88  * ip6t_entry and arpt_entry.  This sucks, and it is a hack.  It will be my
  89  * personal pleasure to remove it -HW
  90  */
  91 struct _xt_align
  92 {
  93         u_int8_t u8;
  94         u_int16_t u16;
  95         u_int32_t u32;
  96         u_int64_t u64;
  97 };
  98
  99 #define XT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1))  \
 100                         & ~(__alignof__(struct _xt_align)-1))
 101
 102 /* Standard return verdict, or do jump. */
 103 #define XT_STANDARD_TARGET ""
 104 /* Error verdict. */
 105 #define XT_ERROR_TARGET "ERROR"
 106
 107 #define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0)
 108 #define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
 109
 110 struct xt_counters
 111 {
 112         u_int64_t pcnt, bcnt;                   /* Packet and byte counters */
 113 };
 114
 115 /* The argument to IPT_SO_ADD_COUNTERS. */
 116 struct xt_counters_info
 117 {
 118         /* Which table. */
 119         char name[XT_TABLE_MAXNAMELEN];
 120
 121         unsigned int num_counters;
 122
 123         /* The counters (actually `number' of these). */
 124         struct xt_counters counters[0];
 125 };
 126
 127 #define XT_INV_PROTO            0x40    /* Invert the sense of PROTO. */
 128
 129 /* fn returns 0 to continue iteration */
 130 #define XT_MATCH_ITERATE(type, e, fn, args...)                  \
 131 ({                                                              \
 132         unsigned int __i;                                       \
 133         int __ret = 0;                                          \
 134         struct xt_entry_match *__m;                             \
 135                                                                 \
 136         for (__i = sizeof(type);                                \
 137              __i < (e)->target_offset;                          \
 138              __i += __m->u.match_size) {                        \
 139                 __m = (void *)e + __i;                          \
 140                                                                 \
 141                 __ret = fn(__m , ## args);                      \
 142                 if (__ret != 0)                                 \
 143                         break;                                  \
 144         }                                                       \
 145         __ret;                                                  \
 146 })
 147
 148 /* fn returns 0 to continue iteration */
 149 #define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
 150 ({                                                              \
 151         unsigned int __i, __n;                                  \
 152         int __ret = 0;                                          \
 153         type *__entry;                                          \
 154                                                                 \
 155         for (__i = 0, __n = 0; __i < (size);                    \
 156              __i += __entry->next_offset, __n++) {              \
 157                 __entry = (void *)(entries) + __i;              \
 158                 if (__n < n)                                    \
 159                         continue;                               \
 160                                                                 \
 161                 __ret = fn(__entry , ## args);                  \
 162                 if (__ret != 0)                                 \
 163                         break;                                  \
 164         }                                                       \
 165         __ret;                                                  \
 166 })
 167
 168 /* fn returns 0 to continue iteration */
 169 #define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
 170         XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)
 171
 172 #ifdef __KERNEL__
 173
 174 #include <linux/netdevice.h>
 175
 176 struct xt_match
 177 {
 178         struct list_head list;
 179
 180         const char name[XT_FUNCTION_MAXNAMELEN-1];
 181
 182         /* Return true or false: return FALSE and set *hotdrop = 1 to
 183            force immediate packet drop. */
 184         /* Arguments changed since 2.6.9, as this must now handle
 185            non-linear skb, using skb_header_pointer and
 186            skb_ip_make_writable. */
 187         int (*match)(const struct sk_buff *skb,
 188                      const struct net_device *in,
 189                      const struct net_device *out,
 190                      const struct xt_match *match,
 191                      const void *matchinfo,
 192                      int offset,
 193                      unsigned int protoff,
 194                      int *hotdrop);
 195
 196         /* Called when user tries to insert an entry of this type. */
 197         /* Should return true or false. */
 198         int (*checkentry)(const char *tablename,
 199                           const void *ip,
 200                           const struct xt_match *match,
 201                           void *matchinfo,
 202                           unsigned int hook_mask);
 203
 204         /* Called when entry of this type deleted. */
 205         void (*destroy)(const struct xt_match *match, void *matchinfo);
 206
 207         /* Called when userspace align differs from kernel space one */
 208         void (*compat_from_user)(void *dst, void *src);
 209         int (*compat_to_user)(void __user *dst, void *src);
 210
 211         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 212         struct module *me;
 213
 214         /* Free to use by each match */
 215         unsigned long data;
 216
 217         char *table;
 218         unsigned int matchsize;
 219         unsigned int compatsize;
 220         unsigned int hooks;
 221         unsigned short proto;
 222
 223         unsigned short family;
 224         u_int8_t revision;
 225 };
 226
 227 /* Registration hooks for targets. */
 228 struct xt_target
 229 {
 230         struct list_head list;
 231
 232         const char name[XT_FUNCTION_MAXNAMELEN-1];
 233
 234         /* Returns verdict. Argument order changed since 2.6.9, as this
 235            must now handle non-linear skbs, using skb_copy_bits and
 236            skb_ip_make_writable. */
 237         unsigned int (*target)(struct sk_buff *skb,
 238                                const struct net_device *in,
 239                                const struct net_device *out,
 240                                unsigned int hooknum,
 241                                const struct xt_target *target,
 242                                const void *targinfo);
 243
 244         /* Called when user tries to insert an entry of this type:
 245            hook_mask is a bitmask of hooks from which it can be
 246            called. */
 247         /* Should return true or false. */
 248         int (*checkentry)(const char *tablename,
 249                           const void *entry,
 250                           const struct xt_target *target,
 251                           void *targinfo,
 252                           unsigned int hook_mask);
 253
 254         /* Called when entry of this type deleted. */
 255         void (*destroy)(const struct xt_target *target, void *targinfo);
 256
 257         /* Called when userspace align differs from kernel space one */
 258         void (*compat_from_user)(void *dst, void *src);
 259         int (*compat_to_user)(void __user *dst, void *src);
 260
 261         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 262         struct module *me;
 263
 264         char *table;
 265         unsigned int targetsize;
 266         unsigned int compatsize;
 267         unsigned int hooks;
 268         unsigned short proto;
 269
 270         unsigned short family;
 271         u_int8_t revision;
 272 };
 273
 274 /* Furniture shopping... */
 275 struct xt_table
 276 {
 277         struct list_head list;
 278
 279         /* A unique name... */
 280         char name[XT_TABLE_MAXNAMELEN];
 281
 282         /* What hooks you will enter on */
 283         unsigned int valid_hooks;
 284
 285         /* Man behind the curtain... */
 286         //struct ip6t_table_info *private;
 287         void *private;
 288
 289         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 290         struct module *me;
 291
 292         int af;         /* address/protocol family */
 293 };
 294
 295 #include <linux/netfilter_ipv4.h>
 296
 297 /* The table itself */
 298 struct xt_table_info
 299 {
 300         /* Size per table */
 301         unsigned int size;
 302         /* Number of entries: FIXME. --RR */
 303         unsigned int number;
 304         /* Initial number of entries. Needed for module usage count */
 305         unsigned int initial_entries;
 306
 307         /* Entry points and underflows */
 308         unsigned int hook_entry[NF_IP_NUMHOOKS];
 309         unsigned int underflow[NF_IP_NUMHOOKS];
 310
 311         /* ipt_entry tables: one per CPU */
 312         /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
 313         void *entries[1];
 314 };
 315
 316 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
 317                           + nr_cpu_ids * sizeof(char *))
 318 extern int xt_register_target(struct xt_target *target);
 319 extern void xt_unregister_target(struct xt_target *target);
 320 extern int xt_register_targets(struct xt_target *target, unsigned int n);
 321 extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
 322
 323 extern int xt_register_match(struct xt_match *target);
 324 extern void xt_unregister_match(struct xt_match *target);
 325 extern int xt_register_matches(struct xt_match *match, unsigned int n);
 326 extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
 327
 328 extern int xt_check_match(const struct xt_match *match, unsigned short family,
 329                           unsigned int size, const char *table, unsigned int hook,
 330                           unsigned short proto, int inv_proto);
 331 extern int xt_check_target(const struct xt_target *target, unsigned short family,
 332                            unsigned int size, const char *table, unsigned int hook,
 333                            unsigned short proto, int inv_proto);
 334
 335 extern int xt_register_table(struct xt_table *table,
 336                              struct xt_table_info *bootstrap,
 337                              struct xt_table_info *newinfo);
 338 extern void *xt_unregister_table(struct xt_table *table);
 339
 340 extern struct xt_table_info *xt_replace_table(struct xt_table *table,
 341                                               unsigned int num_counters,
 342                                               struct xt_table_info *newinfo,
 343                                               int *error);
 344
 345 extern struct xt_match *xt_find_match(int af, const char *name, u8 revision);
 346 extern struct xt_target *xt_find_target(int af, const char *name, u8 revision);
 347 extern struct xt_target *xt_request_find_target(int af, const char *name,
 348                                                 u8 revision);
 349 extern int xt_find_revision(int af, const char *name, u8 revision, int target,
 350                             int *err);
 351
 352 extern struct xt_table *xt_find_table_lock(int af, const char *name);
 353 extern void xt_table_unlock(struct xt_table *t);
 354
 355 extern int xt_proto_init(int af);
 356 extern void xt_proto_fini(int af);
 357
 358 extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
 359 extern void xt_free_table_info(struct xt_table_info *info);
 360
 361 /*
 362  * Per-CPU spinlock associated with per-cpu table entries, and
 363  * with a counter for the "reading" side that allows a recursive
 364  * reader to avoid taking the lock and deadlocking.
 365  *
 366  * "reading" is used by ip/arp/ip6 tables rule processing which runs per-cpu.
 367  * It needs to ensure that the rules are not being changed while the packet
 368  * is being processed. In some cases, the read lock will be acquired
 369  * twice on the same CPU; this is okay because of the count.
 370  *
 371  * "writing" is used when reading counters.
 372  *  During replace any readers that are using the old tables have to complete
 373  *  before freeing the old table. This is handled by the write locking
 374  *  necessary for reading the counters.
 375  */
 376 struct xt_info_lock {
 377         spinlock_t lock;
 378         unsigned char readers;
 379 };
 380 DECLARE_PER_CPU(struct xt_info_lock, xt_info_locks);
 381
 382 /*
 383  * Note: we need to ensure that preemption is disabled before acquiring
 384  * the per-cpu-variable, so we do it as a two step process rather than
 385  * using "spin_lock_bh()".
 386  *
 387  * We _also_ need to disable bottom half processing before updating our
 388  * nesting count, to make sure that the only kind of re-entrancy is this
 389  * code being called by itself: since the count+lock is not an atomic
 390  * operation, we can allow no races.
 391  *
 392  * _Only_ that special combination of being per-cpu and never getting
 393  * re-entered asynchronously means that the count is safe.
 394  */
 395 static inline void xt_info_rdlock_bh(void)
 396 {
 397         struct xt_info_lock *lock;
 398
 399         local_bh_disable();
 400         lock = &__get_cpu_var(xt_info_locks);
 401         if (likely(!lock->readers++))
 402                 spin_lock(&lock->lock);
 403 }
 404
 405 static inline void xt_info_rdunlock_bh(void)
 406 {
 407         struct xt_info_lock *lock = &__get_cpu_var(xt_info_locks);
 408
 409         if (likely(!--lock->readers))
 410                 spin_unlock(&lock->lock);
 411         local_bh_enable();
 412 }
 413
 414 /*
 415  * The "writer" side needs to get exclusive access to the lock,
 416  * regardless of readers.  This must be called with bottom half
 417  * processing (and thus also preemption) disabled.
 418  */
 419 static inline void xt_info_wrlock(unsigned int cpu)
 420 {
 421         spin_lock(&per_cpu(xt_info_locks, cpu).lock);
 422 }
 423
 424 static inline void xt_info_wrunlock(unsigned int cpu)
 425 {
 426         spin_unlock(&per_cpu(xt_info_locks, cpu).lock);
 427 }
 428
 429 /*
 430  * This helper is performance critical and must be inlined
 431  */
 432 static inline unsigned long ifname_compare_aligned(const char *_a,
 433                                                    const char *_b,
 434                                                    const char *_mask)
 435 {
 436         const unsigned long *a = (const unsigned long *)_a;
 437         const unsigned long *b = (const unsigned long *)_b;
 438         const unsigned long *mask = (const unsigned long *)_mask;
 439         unsigned long ret;
 440
 441         ret = (a[0] ^ b[0]) & mask[0];
 442         if (IFNAMSIZ > sizeof(unsigned long))
 443                 ret |= (a[1] ^ b[1]) & mask[1];
 444         if (IFNAMSIZ > 2 * sizeof(unsigned long))
 445                 ret |= (a[2] ^ b[2]) & mask[2];
 446         if (IFNAMSIZ > 3 * sizeof(unsigned long))
 447                 ret |= (a[3] ^ b[3]) & mask[3];
 448         BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
 449         return ret;
 450 }
 451
 452 #ifdef CONFIG_COMPAT
 453 #include <net/compat.h>
 454
 455 struct compat_xt_entry_match
 456 {
 457         union {
 458                 struct {
 459                         u_int16_t match_size;
 460                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 461                         u_int8_t revision;
 462                 } user;
 463                 struct {
 464                         u_int16_t match_size;
 465                         compat_uptr_t match;
 466                 } kernel;
 467                 u_int16_t match_size;
 468         } u;
 469         unsigned char data[0];
 470 };
 471
 472 struct compat_xt_entry_target
 473 {
 474         union {
 475                 struct {
 476                         u_int16_t target_size;
 477                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 478                         u_int8_t revision;
 479                 } user;
 480                 struct {
 481                         u_int16_t target_size;
 482                         compat_uptr_t target;
 483                 } kernel;
 484                 u_int16_t target_size;
 485         } u;
 486         unsigned char data[0];
 487 };
 488
 489 /* FIXME: this works only on 32 bit tasks
 490  * need to change whole approach in order to calculate align as function of
 491  * current task alignment */
 492
 493 struct compat_xt_counters
 494 {
 495 #if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
 496         u_int32_t cnt[4];
 497 #else
 498         u_int64_t cnt[2];
 499 #endif
 500 };
 501
 502 struct compat_xt_counters_info
 503 {
 504         char name[XT_TABLE_MAXNAMELEN];
 505         compat_uint_t num_counters;
 506         struct compat_xt_counters counters[0];
 507 };
 508
 509 #define COMPAT_XT_ALIGN(s) (((s) + (__alignof__(struct compat_xt_counters)-1)) \
 510                 & ~(__alignof__(struct compat_xt_counters)-1))
 511
 512 extern void xt_compat_lock(int af);
 513 extern void xt_compat_unlock(int af);
 514
 515 extern int xt_compat_match_offset(struct xt_match *match);
 516 extern void xt_compat_match_from_user(struct xt_entry_match *m,
 517                                       void **dstptr, int *size);
 518 extern int xt_compat_match_to_user(struct xt_entry_match *m,
 519                                    void __user **dstptr, int *size);
 520
 521 extern int xt_compat_target_offset(struct xt_target *target);
 522 extern void xt_compat_target_from_user(struct xt_entry_target *t,
 523                                        void **dstptr, int *size);
 524 extern int xt_compat_target_to_user(struct xt_entry_target *t,
 525                                     void __user **dstptr, int *size);
 526
 527 #endif /* CONFIG_COMPAT */
 528 #endif /* __KERNEL__ */
 529
 530 #endif /* _X_TABLES_H */