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