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 /**
 177  * struct xt_match_param - parameters for match extensions' match functions
 178  *
 179  * @in:         input netdevice
 180  * @out:        output netdevice
 181  * @match:      struct xt_match through which this function was invoked
 182  * @matchinfo:  per-match data
 183  * @fragoff:    packet is a fragment, this is the data offset
 184  * @thoff:      position of transport header relative to skb->data
 185  * @hotdrop:    drop packet if we had inspection problems
 186  */
 187 struct xt_match_param {
 188         const struct net_device *in, *out;
 189         const struct xt_match *match;
 190         const void *matchinfo;
 191         int fragoff;
 192         unsigned int thoff;
 193         bool *hotdrop;
 194 };
 195
 196 /**
 197  * struct xt_mtchk_param - parameters for match extensions'
 198  * checkentry functions
 199  *
 200  * @table:      table the rule is tried to be inserted into
 201  * @entryinfo:  the family-specific rule data
 202  *              (struct ipt_ip, ip6t_ip, ebt_entry)
 203  * @match:      struct xt_match through which this function was invoked
 204  * @matchinfo:  per-match data
 205  * @hook_mask:  via which hooks the new rule is reachable
 206  */
 207 struct xt_mtchk_param {
 208         const char *table;
 209         const void *entryinfo;
 210         const struct xt_match *match;
 211         void *matchinfo;
 212         unsigned int hook_mask;
 213 };
 214
 215 struct xt_match
 216 {
 217         struct list_head list;
 218
 219         const char name[XT_FUNCTION_MAXNAMELEN-1];
 220
 221         /* Return true or false: return FALSE and set *hotdrop = 1 to
 222            force immediate packet drop. */
 223         /* Arguments changed since 2.6.9, as this must now handle
 224            non-linear skb, using skb_header_pointer and
 225            skb_ip_make_writable. */
 226         bool (*match)(const struct sk_buff *skb,
 227                       const struct xt_match_param *);
 228
 229         /* Called when user tries to insert an entry of this type. */
 230         bool (*checkentry)(const struct xt_mtchk_param *);
 231
 232         /* Called when entry of this type deleted. */
 233         void (*destroy)(const struct xt_match *match, void *matchinfo);
 234
 235         /* Called when userspace align differs from kernel space one */
 236         void (*compat_from_user)(void *dst, void *src);
 237         int (*compat_to_user)(void __user *dst, void *src);
 238
 239         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 240         struct module *me;
 241
 242         /* Free to use by each match */
 243         unsigned long data;
 244
 245         const char *table;
 246         unsigned int matchsize;
 247         unsigned int compatsize;
 248         unsigned int hooks;
 249         unsigned short proto;
 250
 251         unsigned short family;
 252         u_int8_t revision;
 253 };
 254
 255 /* Registration hooks for targets. */
 256 struct xt_target
 257 {
 258         struct list_head list;
 259
 260         const char name[XT_FUNCTION_MAXNAMELEN-1];
 261
 262         /* Returns verdict. Argument order changed since 2.6.9, as this
 263            must now handle non-linear skbs, using skb_copy_bits and
 264            skb_ip_make_writable. */
 265         unsigned int (*target)(struct sk_buff *skb,
 266                                const struct net_device *in,
 267                                const struct net_device *out,
 268                                unsigned int hooknum,
 269                                const struct xt_target *target,
 270                                const void *targinfo);
 271
 272         /* Called when user tries to insert an entry of this type:
 273            hook_mask is a bitmask of hooks from which it can be
 274            called. */
 275         /* Should return true or false. */
 276         bool (*checkentry)(const char *tablename,
 277                            const void *entry,
 278                            const struct xt_target *target,
 279                            void *targinfo,
 280                            unsigned int hook_mask);
 281
 282         /* Called when entry of this type deleted. */
 283         void (*destroy)(const struct xt_target *target, void *targinfo);
 284
 285         /* Called when userspace align differs from kernel space one */
 286         void (*compat_from_user)(void *dst, void *src);
 287         int (*compat_to_user)(void __user *dst, void *src);
 288
 289         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 290         struct module *me;
 291
 292         const char *table;
 293         unsigned int targetsize;
 294         unsigned int compatsize;
 295         unsigned int hooks;
 296         unsigned short proto;
 297
 298         unsigned short family;
 299         u_int8_t revision;
 300 };
 301
 302 /* Furniture shopping... */
 303 struct xt_table
 304 {
 305         struct list_head list;
 306
 307         /* A unique name... */
 308         const char name[XT_TABLE_MAXNAMELEN];
 309
 310         /* What hooks you will enter on */
 311         unsigned int valid_hooks;
 312
 313         /* Lock for the curtain */
 314         rwlock_t lock;
 315
 316         /* Man behind the curtain... */
 317         //struct ip6t_table_info *private;
 318         void *private;
 319
 320         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 321         struct module *me;
 322
 323         u_int8_t af;            /* address/protocol family */
 324 };
 325
 326 #include <linux/netfilter_ipv4.h>
 327
 328 /* The table itself */
 329 struct xt_table_info
 330 {
 331         /* Size per table */
 332         unsigned int size;
 333         /* Number of entries: FIXME. --RR */
 334         unsigned int number;
 335         /* Initial number of entries. Needed for module usage count */
 336         unsigned int initial_entries;
 337
 338         /* Entry points and underflows */
 339         unsigned int hook_entry[NF_INET_NUMHOOKS];
 340         unsigned int underflow[NF_INET_NUMHOOKS];
 341
 342         /* ipt_entry tables: one per CPU */
 343         /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
 344         char *entries[1];
 345 };
 346
 347 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
 348                           + nr_cpu_ids * sizeof(char *))
 349 extern int xt_register_target(struct xt_target *target);
 350 extern void xt_unregister_target(struct xt_target *target);
 351 extern int xt_register_targets(struct xt_target *target, unsigned int n);
 352 extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
 353
 354 extern int xt_register_match(struct xt_match *target);
 355 extern void xt_unregister_match(struct xt_match *target);
 356 extern int xt_register_matches(struct xt_match *match, unsigned int n);
 357 extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
 358
 359 extern int xt_check_match(struct xt_mtchk_param *, u_int8_t family,
 360                           unsigned int size, u_int8_t proto, bool inv_proto);
 361 extern int xt_check_target(const struct xt_target *target, unsigned short family,
 362                            unsigned int size, const char *table, unsigned int hook,
 363                            unsigned short proto, int inv_proto,
 364                            const void *entry, void *targinfo);
 365
 366 extern struct xt_table *xt_register_table(struct net *net,
 367                                           struct xt_table *table,
 368                                           struct xt_table_info *bootstrap,
 369                                           struct xt_table_info *newinfo);
 370 extern void *xt_unregister_table(struct xt_table *table);
 371
 372 extern struct xt_table_info *xt_replace_table(struct xt_table *table,
 373                                               unsigned int num_counters,
 374                                               struct xt_table_info *newinfo,
 375                                               int *error);
 376
 377 extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
 378 extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
 379 extern struct xt_target *xt_request_find_target(u8 af, const char *name,
 380                                                 u8 revision);
 381 extern int xt_find_revision(u8 af, const char *name, u8 revision,
 382                             int target, int *err);
 383
 384 extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 385                                            const char *name);
 386 extern void xt_table_unlock(struct xt_table *t);
 387
 388 extern int xt_proto_init(struct net *net, u_int8_t af);
 389 extern void xt_proto_fini(struct net *net, u_int8_t af);
 390
 391 extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
 392 extern void xt_free_table_info(struct xt_table_info *info);
 393
 394 #ifdef CONFIG_COMPAT
 395 #include <net/compat.h>
 396
 397 struct compat_xt_entry_match
 398 {
 399         union {
 400                 struct {
 401                         u_int16_t match_size;
 402                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 403                         u_int8_t revision;
 404                 } user;
 405                 struct {
 406                         u_int16_t match_size;
 407                         compat_uptr_t match;
 408                 } kernel;
 409                 u_int16_t match_size;
 410         } u;
 411         unsigned char data[0];
 412 };
 413
 414 struct compat_xt_entry_target
 415 {
 416         union {
 417                 struct {
 418                         u_int16_t target_size;
 419                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 420                         u_int8_t revision;
 421                 } user;
 422                 struct {
 423                         u_int16_t target_size;
 424                         compat_uptr_t target;
 425                 } kernel;
 426                 u_int16_t target_size;
 427         } u;
 428         unsigned char data[0];
 429 };
 430
 431 /* FIXME: this works only on 32 bit tasks
 432  * need to change whole approach in order to calculate align as function of
 433  * current task alignment */
 434
 435 struct compat_xt_counters
 436 {
 437 #if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
 438         u_int32_t cnt[4];
 439 #else
 440         u_int64_t cnt[2];
 441 #endif
 442 };
 443
 444 struct compat_xt_counters_info
 445 {
 446         char name[XT_TABLE_MAXNAMELEN];
 447         compat_uint_t num_counters;
 448         struct compat_xt_counters counters[0];
 449 };
 450
 451 #define COMPAT_XT_ALIGN(s) (((s) + (__alignof__(struct compat_xt_counters)-1)) \
 452                 & ~(__alignof__(struct compat_xt_counters)-1))
 453
 454 extern void xt_compat_lock(u_int8_t af);
 455 extern void xt_compat_unlock(u_int8_t af);
 456
 457 extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta);
 458 extern void xt_compat_flush_offsets(u_int8_t af);
 459 extern short xt_compat_calc_jump(u_int8_t af, unsigned int offset);
 460
 461 extern int xt_compat_match_offset(const struct xt_match *match);
 462 extern int xt_compat_match_from_user(struct xt_entry_match *m,
 463                                      void **dstptr, unsigned int *size);
 464 extern int xt_compat_match_to_user(struct xt_entry_match *m,
 465                                    void __user **dstptr, unsigned int *size);
 466
 467 extern int xt_compat_target_offset(const struct xt_target *target);
 468 extern void xt_compat_target_from_user(struct xt_entry_target *t,
 469                                        void **dstptr, unsigned int *size);
 470 extern int xt_compat_target_to_user(struct xt_entry_target *t,
 471                                     void __user **dstptr, unsigned int *size);
 472
 473 #endif /* CONFIG_COMPAT */
 474 #endif /* __KERNEL__ */
 475
 476 #endif /* _X_TABLES_H */