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 /* Match destructor parameters */
 216 struct xt_mtdtor_param {
 217         const struct xt_match *match;
 218         void *matchinfo;
 219 };
 220
 221 /**
 222  * struct xt_target_param - parameters for target extensions' target functions
 223  *
 224  * @hooknum:    hook through which this target was invoked
 225  * @target:     struct xt_target through which this function was invoked
 226  * @targinfo:   per-target data
 227  *
 228  * Other fields see above.
 229  */
 230 struct xt_target_param {
 231         const struct net_device *in, *out;
 232         unsigned int hooknum;
 233         const struct xt_target *target;
 234         const void *targinfo;
 235 };
 236
 237 struct xt_match
 238 {
 239         struct list_head list;
 240
 241         const char name[XT_FUNCTION_MAXNAMELEN-1];
 242
 243         /* Return true or false: return FALSE and set *hotdrop = 1 to
 244            force immediate packet drop. */
 245         /* Arguments changed since 2.6.9, as this must now handle
 246            non-linear skb, using skb_header_pointer and
 247            skb_ip_make_writable. */
 248         bool (*match)(const struct sk_buff *skb,
 249                       const struct xt_match_param *);
 250
 251         /* Called when user tries to insert an entry of this type. */
 252         bool (*checkentry)(const struct xt_mtchk_param *);
 253
 254         /* Called when entry of this type deleted. */
 255         void (*destroy)(const struct xt_mtdtor_param *);
 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         /* Free to use by each match */
 265         unsigned long data;
 266
 267         const char *table;
 268         unsigned int matchsize;
 269         unsigned int compatsize;
 270         unsigned int hooks;
 271         unsigned short proto;
 272
 273         unsigned short family;
 274         u_int8_t revision;
 275 };
 276
 277 /* Registration hooks for targets. */
 278 struct xt_target
 279 {
 280         struct list_head list;
 281
 282         const char name[XT_FUNCTION_MAXNAMELEN-1];
 283
 284         /* Returns verdict. Argument order changed since 2.6.9, as this
 285            must now handle non-linear skbs, using skb_copy_bits and
 286            skb_ip_make_writable. */
 287         unsigned int (*target)(struct sk_buff *skb,
 288                                const struct xt_target_param *);
 289
 290         /* Called when user tries to insert an entry of this type:
 291            hook_mask is a bitmask of hooks from which it can be
 292            called. */
 293         /* Should return true or false. */
 294         bool (*checkentry)(const char *tablename,
 295                            const void *entry,
 296                            const struct xt_target *target,
 297                            void *targinfo,
 298                            unsigned int hook_mask);
 299
 300         /* Called when entry of this type deleted. */
 301         void (*destroy)(const struct xt_target *target, void *targinfo);
 302
 303         /* Called when userspace align differs from kernel space one */
 304         void (*compat_from_user)(void *dst, void *src);
 305         int (*compat_to_user)(void __user *dst, void *src);
 306
 307         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 308         struct module *me;
 309
 310         const char *table;
 311         unsigned int targetsize;
 312         unsigned int compatsize;
 313         unsigned int hooks;
 314         unsigned short proto;
 315
 316         unsigned short family;
 317         u_int8_t revision;
 318 };
 319
 320 /* Furniture shopping... */
 321 struct xt_table
 322 {
 323         struct list_head list;
 324
 325         /* A unique name... */
 326         const char name[XT_TABLE_MAXNAMELEN];
 327
 328         /* What hooks you will enter on */
 329         unsigned int valid_hooks;
 330
 331         /* Lock for the curtain */
 332         rwlock_t lock;
 333
 334         /* Man behind the curtain... */
 335         //struct ip6t_table_info *private;
 336         void *private;
 337
 338         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 339         struct module *me;
 340
 341         u_int8_t af;            /* address/protocol family */
 342 };
 343
 344 #include <linux/netfilter_ipv4.h>
 345
 346 /* The table itself */
 347 struct xt_table_info
 348 {
 349         /* Size per table */
 350         unsigned int size;
 351         /* Number of entries: FIXME. --RR */
 352         unsigned int number;
 353         /* Initial number of entries. Needed for module usage count */
 354         unsigned int initial_entries;
 355
 356         /* Entry points and underflows */
 357         unsigned int hook_entry[NF_INET_NUMHOOKS];
 358         unsigned int underflow[NF_INET_NUMHOOKS];
 359
 360         /* ipt_entry tables: one per CPU */
 361         /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
 362         char *entries[1];
 363 };
 364
 365 #define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
 366                           + nr_cpu_ids * sizeof(char *))
 367 extern int xt_register_target(struct xt_target *target);
 368 extern void xt_unregister_target(struct xt_target *target);
 369 extern int xt_register_targets(struct xt_target *target, unsigned int n);
 370 extern void xt_unregister_targets(struct xt_target *target, unsigned int n);
 371
 372 extern int xt_register_match(struct xt_match *target);
 373 extern void xt_unregister_match(struct xt_match *target);
 374 extern int xt_register_matches(struct xt_match *match, unsigned int n);
 375 extern void xt_unregister_matches(struct xt_match *match, unsigned int n);
 376
 377 extern int xt_check_match(struct xt_mtchk_param *, u_int8_t family,
 378                           unsigned int size, u_int8_t proto, bool inv_proto);
 379 extern int xt_check_target(const struct xt_target *target, unsigned short family,
 380                            unsigned int size, const char *table, unsigned int hook,
 381                            unsigned short proto, int inv_proto,
 382                            const void *entry, void *targinfo);
 383
 384 extern struct xt_table *xt_register_table(struct net *net,
 385                                           struct xt_table *table,
 386                                           struct xt_table_info *bootstrap,
 387                                           struct xt_table_info *newinfo);
 388 extern void *xt_unregister_table(struct xt_table *table);
 389
 390 extern struct xt_table_info *xt_replace_table(struct xt_table *table,
 391                                               unsigned int num_counters,
 392                                               struct xt_table_info *newinfo,
 393                                               int *error);
 394
 395 extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
 396 extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
 397 extern struct xt_target *xt_request_find_target(u8 af, const char *name,
 398                                                 u8 revision);
 399 extern int xt_find_revision(u8 af, const char *name, u8 revision,
 400                             int target, int *err);
 401
 402 extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 403                                            const char *name);
 404 extern void xt_table_unlock(struct xt_table *t);
 405
 406 extern int xt_proto_init(struct net *net, u_int8_t af);
 407 extern void xt_proto_fini(struct net *net, u_int8_t af);
 408
 409 extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
 410 extern void xt_free_table_info(struct xt_table_info *info);
 411
 412 #ifdef CONFIG_COMPAT
 413 #include <net/compat.h>
 414
 415 struct compat_xt_entry_match
 416 {
 417         union {
 418                 struct {
 419                         u_int16_t match_size;
 420                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 421                         u_int8_t revision;
 422                 } user;
 423                 struct {
 424                         u_int16_t match_size;
 425                         compat_uptr_t match;
 426                 } kernel;
 427                 u_int16_t match_size;
 428         } u;
 429         unsigned char data[0];
 430 };
 431
 432 struct compat_xt_entry_target
 433 {
 434         union {
 435                 struct {
 436                         u_int16_t target_size;
 437                         char name[XT_FUNCTION_MAXNAMELEN - 1];
 438                         u_int8_t revision;
 439                 } user;
 440                 struct {
 441                         u_int16_t target_size;
 442                         compat_uptr_t target;
 443                 } kernel;
 444                 u_int16_t target_size;
 445         } u;
 446         unsigned char data[0];
 447 };
 448
 449 /* FIXME: this works only on 32 bit tasks
 450  * need to change whole approach in order to calculate align as function of
 451  * current task alignment */
 452
 453 struct compat_xt_counters
 454 {
 455 #if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
 456         u_int32_t cnt[4];
 457 #else
 458         u_int64_t cnt[2];
 459 #endif
 460 };
 461
 462 struct compat_xt_counters_info
 463 {
 464         char name[XT_TABLE_MAXNAMELEN];
 465         compat_uint_t num_counters;
 466         struct compat_xt_counters counters[0];
 467 };
 468
 469 #define COMPAT_XT_ALIGN(s) (((s) + (__alignof__(struct compat_xt_counters)-1)) \
 470                 & ~(__alignof__(struct compat_xt_counters)-1))
 471
 472 extern void xt_compat_lock(u_int8_t af);
 473 extern void xt_compat_unlock(u_int8_t af);
 474
 475 extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta);
 476 extern void xt_compat_flush_offsets(u_int8_t af);
 477 extern short xt_compat_calc_jump(u_int8_t af, unsigned int offset);
 478
 479 extern int xt_compat_match_offset(const struct xt_match *match);
 480 extern int xt_compat_match_from_user(struct xt_entry_match *m,
 481                                      void **dstptr, unsigned int *size);
 482 extern int xt_compat_match_to_user(struct xt_entry_match *m,
 483                                    void __user **dstptr, unsigned int *size);
 484
 485 extern int xt_compat_target_offset(const struct xt_target *target);
 486 extern void xt_compat_target_from_user(struct xt_entry_target *t,
 487                                        void **dstptr, unsigned int *size);
 488 extern int xt_compat_target_to_user(struct xt_entry_target *t,
 489                                     void __user **dstptr, unsigned int *size);
 490
 491 #endif /* CONFIG_COMPAT */
 492 #endif /* __KERNEL__ */
 493
 494 #endif /* _X_TABLES_H */