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  * @family:     Actual NFPROTO_* through which the function is invoked
 187  *              (helpful when match->family == NFPROTO_UNSPEC)
 188  */
 189 struct xt_match_param {
 190         const struct net_device *in, *out;
 191         const struct xt_match *match;
 192         const void *matchinfo;
 193         int fragoff;
 194         unsigned int thoff;
 195         bool *hotdrop;
 196         u_int8_t family;
 197 };
 198
 199 /**
 200  * struct xt_mtchk_param - parameters for match extensions'
 201  * checkentry functions
 202  *
 203  * @table:      table the rule is tried to be inserted into
 204  * @entryinfo:  the family-specific rule data
 205  *              (struct ipt_ip, ip6t_ip, ebt_entry)
 206  * @match:      struct xt_match through which this function was invoked
 207  * @matchinfo:  per-match data
 208  * @hook_mask:  via which hooks the new rule is reachable
 209  */
 210 struct xt_mtchk_param {
 211         const char *table;
 212         const void *entryinfo;
 213         const struct xt_match *match;
 214         void *matchinfo;
 215         unsigned int hook_mask;
 216         u_int8_t family;
 217 };
 218
 219 /* Match destructor parameters */
 220 struct xt_mtdtor_param {
 221         const struct xt_match *match;
 222         void *matchinfo;
 223         u_int8_t family;
 224 };
 225
 226 /**
 227  * struct xt_target_param - parameters for target extensions' target functions
 228  *
 229  * @hooknum:    hook through which this target was invoked
 230  * @target:     struct xt_target through which this function was invoked
 231  * @targinfo:   per-target data
 232  *
 233  * Other fields see above.
 234  */
 235 struct xt_target_param {
 236         const struct net_device *in, *out;
 237         unsigned int hooknum;
 238         const struct xt_target *target;
 239         const void *targinfo;
 240         u_int8_t family;
 241 };
 242
 243 /**
 244  * struct xt_tgchk_param - parameters for target extensions'
 245  * checkentry functions
 246  *
 247  * @entryinfo:  the family-specific rule data
 248  *              (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
 249  *
 250  * Other fields see above.
 251  */
 252 struct xt_tgchk_param {
 253         const char *table;
 254         const void *entryinfo;
 255         const struct xt_target *target;
 256         void *targinfo;
 257         unsigned int hook_mask;
 258         u_int8_t family;
 259 };
 260
 261 /* Target destructor parameters */
 262 struct xt_tgdtor_param {
 263         const struct xt_target *target;
 264         void *targinfo;
 265         u_int8_t family;
 266 };
 267
 268 struct xt_match
 269 {
 270         struct list_head list;
 271
 272         const char name[XT_FUNCTION_MAXNAMELEN-1];
 273         u_int8_t revision;
 274
 275         /* Return true or false: return FALSE and set *hotdrop = 1 to
 276            force immediate packet drop. */
 277         /* Arguments changed since 2.6.9, as this must now handle
 278            non-linear skb, using skb_header_pointer and
 279            skb_ip_make_writable. */
 280         bool (*match)(const struct sk_buff *skb,
 281                       const struct xt_match_param *);
 282
 283         /* Called when user tries to insert an entry of this type. */
 284         bool (*checkentry)(const struct xt_mtchk_param *);
 285
 286         /* Called when entry of this type deleted. */
 287         void (*destroy)(const struct xt_mtdtor_param *);
 288
 289         /* Called when userspace align differs from kernel space one */
 290         void (*compat_from_user)(void *dst, void *src);
 291         int (*compat_to_user)(void __user *dst, void *src);
 292
 293         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 294         struct module *me;
 295
 296         /* Free to use by each match */
 297         unsigned long data;
 298
 299         const char *table;
 300         unsigned int matchsize;
 301         unsigned int compatsize;
 302         unsigned int hooks;
 303         unsigned short proto;
 304
 305         unsigned short family;
 306 };
 307
 308 /* Registration hooks for targets. */
 309 struct xt_target
 310 {
 311         struct list_head list;
 312
 313         const char name[XT_FUNCTION_MAXNAMELEN-1];
 314
 315         /* Returns verdict. Argument order changed since 2.6.9, as this
 316            must now handle non-linear skbs, using skb_copy_bits and
 317            skb_ip_make_writable. */
 318         unsigned int (*target)(struct sk_buff *skb,
 319                                const struct xt_target_param *);
 320
 321         /* Called when user tries to insert an entry of this type:
 322            hook_mask is a bitmask of hooks from which it can be
 323            called. */
 324         /* Should return true or false. */
 325         bool (*checkentry)(const struct xt_tgchk_param *);
 326
 327         /* Called when entry of this type deleted. */
 328         void (*destroy)(const struct xt_tgdtor_param *);
 329
 330         /* Called when userspace align differs from kernel space one */
 331         void (*compat_from_user)(void *dst, void *src);
 332         int (*compat_to_user)(void __user *dst, void *src);
 333
 334         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 335         struct module *me;
 336
 337         const char *table;
 338         unsigned int targetsize;
 339         unsigned int compatsize;
 340         unsigned int hooks;
 341         unsigned short proto;
 342
 343         unsigned short family;
 344         u_int8_t revision;
 345 };
 346
 347 /* Furniture shopping... */
 348 struct xt_table
 349 {
 350         struct list_head list;
 351
 352         /* What hooks you will enter on */
 353         unsigned int valid_hooks;
 354
 355         /* Lock for the curtain */
 356         rwlock_t lock;
 357
 358         /* Man behind the curtain... */
 359         struct xt_table_info *private;
 360
 361         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 362         struct module *me;
 363
 364         u_int8_t af;            /* address/protocol family */
 365
 366         /* A unique name... */
 367         const char name[XT_TABLE_MAXNAMELEN];
 368 };
 369
 370 #include <linux/netfilter_ipv4.h>
 371
 372 /* The table itself */
 373 struct xt_table_info
 374 {
 375         /* Size per table */
 376         unsigned int size;
 377         /* Number of entries: FIXME. --RR */
 378         unsigned int number;
 379         /* Initial number of entries. Needed for module usage count */
 380         unsigned int initial_entries;
 381
 382         /* Entry points and underflows */
 383         unsigned int hook_entry[NF_INET_NUMHOOKS];
 384         unsigned int underflow[NF_INET_NUMHOOKS];
 385
 386         /* ipt_entry tables: one per CPU */
 387         /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
 388         char *entries[1];
 389 };
 390
 391 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
 392                           + nr_cpu_ids * sizeof(char *))
 393 extern int xt_register_target(struct xt_target *target);
 394 extern void xt_unregister_target(struct xt_target *target);
 395 extern int xt_register_targets(struct xt_target *target, unsigned int n);
 396 extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
 397
 398 extern int xt_register_match(struct xt_match *target);
 399 extern void xt_unregister_match(struct xt_match *target);
 400 extern int xt_register_matches(struct xt_match *match, unsigned int n);
 401 extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
 402
 403 extern int xt_check_match(struct xt_mtchk_param *,
 404                           unsigned int size, u_int8_t proto, bool inv_proto);
 405 extern int xt_check_target(struct xt_tgchk_param *,
 406                            unsigned int size, u_int8_t proto, bool inv_proto);
 407
 408 extern struct xt_table *xt_register_table(struct net *net,
 409                                           struct xt_table *table,
 410                                           struct xt_table_info *bootstrap,
 411                                           struct xt_table_info *newinfo);
 412 extern void *xt_unregister_table(struct xt_table *table);
 413
 414 extern struct xt_table_info *xt_replace_table(struct xt_table *table,
 415                                               unsigned int num_counters,
 416                                               struct xt_table_info *newinfo,
 417                                               int *error);
 418
 419 extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
 420 extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
 421 extern struct xt_target *xt_request_find_target(u8 af, const char *name,
 422                                                 u8 revision);
 423 extern int xt_find_revision(u8 af, const char *name, u8 revision,
 424                             int target, int *err);
 425
 426 extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 427                                            const char *name);
 428 extern void xt_table_unlock(struct xt_table *t);
 429
 430 extern int xt_proto_init(struct net *net, u_int8_t af);
 431 extern void xt_proto_fini(struct net *net, u_int8_t af);
 432
 433 extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
 434 extern void xt_free_table_info(struct xt_table_info *info);
 435
 436 #ifdef CONFIG_COMPAT
 437 #include <net/compat.h>
 438
 439 struct compat_xt_entry_match
 440 {
 441         union {
 442                 struct {
 443                         u_int16_t match_size;
 444                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 445                         u_int8_t revision;
 446                 } user;
 447                 struct {
 448                         u_int16_t match_size;
 449                         compat_uptr_t match;
 450                 } kernel;
 451                 u_int16_t match_size;
 452         } u;
 453         unsigned char data[0];
 454 };
 455
 456 struct compat_xt_entry_target
 457 {
 458         union {
 459                 struct {
 460                         u_int16_t target_size;
 461                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 462                         u_int8_t revision;
 463                 } user;
 464                 struct {
 465                         u_int16_t target_size;
 466                         compat_uptr_t target;
 467                 } kernel;
 468                 u_int16_t target_size;
 469         } u;
 470         unsigned char data[0];
 471 };
 472
 473 /* FIXME: this works only on 32 bit tasks
 474  * need to change whole approach in order to calculate align as function of
 475  * current task alignment */
 476
 477 struct compat_xt_counters
 478 {
 479 #if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
 480         u_int32_t cnt[4];
 481 #else
 482         u_int64_t cnt[2];
 483 #endif
 484 };
 485
 486 struct compat_xt_counters_info
 487 {
 488         char name[XT_TABLE_MAXNAMELEN];
 489         compat_uint_t num_counters;
 490         struct compat_xt_counters counters[0];
 491 };
 492
 493 #define COMPAT_XT_ALIGN(s) (((s) + (__alignof__(struct compat_xt_counters)-1)) \
 494                 & ~(__alignof__(struct compat_xt_counters)-1))
 495
 496 extern void xt_compat_lock(u_int8_t af);
 497 extern void xt_compat_unlock(u_int8_t af);
 498
 499 extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta);
 500 extern void xt_compat_flush_offsets(u_int8_t af);
 501 extern short xt_compat_calc_jump(u_int8_t af, unsigned int offset);
 502
 503 extern int xt_compat_match_offset(const struct xt_match *match);
 504 extern int xt_compat_match_from_user(struct xt_entry_match *m,
 505                                      void **dstptr, unsigned int *size);
 506 extern int xt_compat_match_to_user(struct xt_entry_match *m,
 507                                    void __user **dstptr, unsigned int *size);
 508
 509 extern int xt_compat_target_offset(const struct xt_target *target);
 510 extern void xt_compat_target_from_user(struct xt_entry_target *t,
 511                                        void **dstptr, unsigned int *size);
 512 extern int xt_compat_target_to_user(struct xt_entry_target *t,
 513                                     void __user **dstptr, unsigned int *size);
 514
 515 #endif /* CONFIG_COMPAT */
 516 #endif /* __KERNEL__ */
 517
 518 #endif /* _X_TABLES_H */