include/linux/netfilter_ipv4/ip_tables.h

   1 /*
   2  * 25-Jul-1998 Major changes to allow for ip chain table
   3  *
   4  * 3-Jan-2000 Named tables to allow packet selection for different uses.
   5  */
   6
   7 /*
   8  *      Format of an IP firewall descriptor
   9  *
  10  *      src, dst, src_mask, dst_mask are always stored in network byte order.
  11  *      flags are stored in host byte order (of course).
  12  *      Port numbers are stored in HOST byte order.
  13  */
  14
  15 #ifndef _IPTABLES_H
  16 #define _IPTABLES_H
  17
  18 #ifdef __KERNEL__
  19 #include <linux/if.h>
  20 #include <linux/types.h>
  21 #include <linux/in.h>
  22 #include <linux/ip.h>
  23 #include <linux/skbuff.h>
  24 #endif
  25 #include <linux/compiler.h>
  26 #include <linux/netfilter_ipv4.h>
  27
  28 #define IPT_FUNCTION_MAXNAMELEN 30
  29 #define IPT_TABLE_MAXNAMELEN 32
  30
  31 /* Yes, Virginia, you have to zero the padding. */
  32 struct ipt_ip {
  33         /* Source and destination IP addr */
  34         struct in_addr src, dst;
  35         /* Mask for src and dest IP addr */
  36         struct in_addr smsk, dmsk;
  37         char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
  38         unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
  39
  40         /* Protocol, 0 = ANY */
  41         u_int16_t proto;
  42
  43         /* Flags word */
  44         u_int8_t flags;
  45         /* Inverse flags */
  46         u_int8_t invflags;
  47 };
  48
  49 struct ipt_entry_match
  50 {
  51         union {
  52                 struct {
  53                         u_int16_t match_size;
  54
  55                         /* Used by userspace */
  56                         char name[IPT_FUNCTION_MAXNAMELEN-1];
  57
  58                         u_int8_t revision;
  59                 } user;
  60                 struct {
  61                         u_int16_t match_size;
  62
  63                         /* Used inside the kernel */
  64                         struct ipt_match *match;
  65                 } kernel;
  66
  67                 /* Total length */
  68                 u_int16_t match_size;
  69         } u;
  70
  71         unsigned char data[0];
  72 };
  73
  74 struct ipt_entry_target
  75 {
  76         union {
  77                 struct {
  78                         u_int16_t target_size;
  79
  80                         /* Used by userspace */
  81                         char name[IPT_FUNCTION_MAXNAMELEN-1];
  82
  83                         u_int8_t revision;
  84                 } user;
  85                 struct {
  86                         u_int16_t target_size;
  87
  88                         /* Used inside the kernel */
  89                         struct ipt_target *target;
  90                 } kernel;
  91
  92                 /* Total length */
  93                 u_int16_t target_size;
  94         } u;
  95
  96         unsigned char data[0];
  97 };
  98
  99 struct ipt_standard_target
 100 {
 101         struct ipt_entry_target target;
 102         int verdict;
 103 };
 104
 105 struct ipt_counters
 106 {
 107         u_int64_t pcnt, bcnt;                   /* Packet and byte counters */
 108 };
 109
 110 /* Values for "flag" field in struct ipt_ip (general ip structure). */
 111 #define IPT_F_FRAG              0x01    /* Set if rule is a fragment rule */
 112 #define IPT_F_MASK              0x01    /* All possible flag bits mask. */
 113
 114 /* Values for "inv" field in struct ipt_ip. */
 115 #define IPT_INV_VIA_IN          0x01    /* Invert the sense of IN IFACE. */
 116 #define IPT_INV_VIA_OUT         0x02    /* Invert the sense of OUT IFACE */
 117 #define IPT_INV_TOS             0x04    /* Invert the sense of TOS. */
 118 #define IPT_INV_SRCIP           0x08    /* Invert the sense of SRC IP. */
 119 #define IPT_INV_DSTIP           0x10    /* Invert the sense of DST OP. */
 120 #define IPT_INV_FRAG            0x20    /* Invert the sense of FRAG. */
 121 #define IPT_INV_PROTO           0x40    /* Invert the sense of PROTO. */
 122 #define IPT_INV_MASK            0x7F    /* All possible flag bits mask. */
 123
 124 /* This structure defines each of the firewall rules.  Consists of 3
 125    parts which are 1) general IP header stuff 2) match specific
 126    stuff 3) the target to perform if the rule matches */
 127 struct ipt_entry
 128 {
 129         struct ipt_ip ip;
 130
 131         /* Mark with fields that we care about. */
 132         unsigned int nfcache;
 133
 134         /* Size of ipt_entry + matches */
 135         u_int16_t target_offset;
 136         /* Size of ipt_entry + matches + target */
 137         u_int16_t next_offset;
 138
 139         /* Back pointer */
 140         unsigned int comefrom;
 141
 142         /* Packet and byte counters. */
 143         struct ipt_counters counters;
 144
 145         /* The matches (if any), then the target. */
 146         unsigned char elems[0];
 147 };
 148
 149 /*
 150  * New IP firewall options for [gs]etsockopt at the RAW IP level.
 151  * Unlike BSD Linux inherits IP options so you don't have to use a raw
 152  * socket for this. Instead we check rights in the calls. */
 153 #define IPT_BASE_CTL            64      /* base for firewall socket options */
 154
 155 #define IPT_SO_SET_REPLACE      (IPT_BASE_CTL)
 156 #define IPT_SO_SET_ADD_COUNTERS (IPT_BASE_CTL + 1)
 157 #define IPT_SO_SET_MAX          IPT_SO_SET_ADD_COUNTERS
 158
 159 #define IPT_SO_GET_INFO                 (IPT_BASE_CTL)
 160 #define IPT_SO_GET_ENTRIES              (IPT_BASE_CTL + 1)
 161 #define IPT_SO_GET_REVISION_MATCH       (IPT_BASE_CTL + 2)
 162 #define IPT_SO_GET_REVISION_TARGET      (IPT_BASE_CTL + 3)
 163 #define IPT_SO_GET_MAX                  IPT_SO_GET_REVISION_TARGET
 164
 165 /* CONTINUE verdict for targets */
 166 #define IPT_CONTINUE 0xFFFFFFFF
 167
 168 /* For standard target */
 169 #define IPT_RETURN (-NF_REPEAT - 1)
 170
 171 /* TCP matching stuff */
 172 struct ipt_tcp
 173 {
 174         u_int16_t spts[2];                      /* Source port range. */
 175         u_int16_t dpts[2];                      /* Destination port range. */
 176         u_int8_t option;                        /* TCP Option iff non-zero*/
 177         u_int8_t flg_mask;                      /* TCP flags mask byte */
 178         u_int8_t flg_cmp;                       /* TCP flags compare byte */
 179         u_int8_t invflags;                      /* Inverse flags */
 180 };
 181
 182 /* Values for "inv" field in struct ipt_tcp. */
 183 #define IPT_TCP_INV_SRCPT       0x01    /* Invert the sense of source ports. */
 184 #define IPT_TCP_INV_DSTPT       0x02    /* Invert the sense of dest ports. */
 185 #define IPT_TCP_INV_FLAGS       0x04    /* Invert the sense of TCP flags. */
 186 #define IPT_TCP_INV_OPTION      0x08    /* Invert the sense of option test. */
 187 #define IPT_TCP_INV_MASK        0x0F    /* All possible flags. */
 188
 189 /* UDP matching stuff */
 190 struct ipt_udp
 191 {
 192         u_int16_t spts[2];                      /* Source port range. */
 193         u_int16_t dpts[2];                      /* Destination port range. */
 194         u_int8_t invflags;                      /* Inverse flags */
 195 };
 196
 197 /* Values for "invflags" field in struct ipt_udp. */
 198 #define IPT_UDP_INV_SRCPT       0x01    /* Invert the sense of source ports. */
 199 #define IPT_UDP_INV_DSTPT       0x02    /* Invert the sense of dest ports. */
 200 #define IPT_UDP_INV_MASK        0x03    /* All possible flags. */
 201
 202 /* ICMP matching stuff */
 203 struct ipt_icmp
 204 {
 205         u_int8_t type;                          /* type to match */
 206         u_int8_t code[2];                       /* range of code */
 207         u_int8_t invflags;                      /* Inverse flags */
 208 };
 209
 210 /* Values for "inv" field for struct ipt_icmp. */
 211 #define IPT_ICMP_INV    0x01    /* Invert the sense of type/code test */
 212
 213 /* The argument to IPT_SO_GET_INFO */
 214 struct ipt_getinfo
 215 {
 216         /* Which table: caller fills this in. */
 217         char name[IPT_TABLE_MAXNAMELEN];
 218
 219         /* Kernel fills these in. */
 220         /* Which hook entry points are valid: bitmask */
 221         unsigned int valid_hooks;
 222
 223         /* Hook entry points: one per netfilter hook. */
 224         unsigned int hook_entry[NF_IP_NUMHOOKS];
 225
 226         /* Underflow points. */
 227         unsigned int underflow[NF_IP_NUMHOOKS];
 228
 229         /* Number of entries */
 230         unsigned int num_entries;
 231
 232         /* Size of entries. */
 233         unsigned int size;
 234 };
 235
 236 /* The argument to IPT_SO_SET_REPLACE. */
 237 struct ipt_replace
 238 {
 239         /* Which table. */
 240         char name[IPT_TABLE_MAXNAMELEN];
 241
 242         /* Which hook entry points are valid: bitmask.  You can't
 243            change this. */
 244         unsigned int valid_hooks;
 245
 246         /* Number of entries */
 247         unsigned int num_entries;
 248
 249         /* Total size of new entries */
 250         unsigned int size;
 251
 252         /* Hook entry points. */
 253         unsigned int hook_entry[NF_IP_NUMHOOKS];
 254
 255         /* Underflow points. */
 256         unsigned int underflow[NF_IP_NUMHOOKS];
 257
 258         /* Information about old entries: */
 259         /* Number of counters (must be equal to current number of entries). */
 260         unsigned int num_counters;
 261         /* The old entries' counters. */
 262         struct ipt_counters __user *counters;
 263
 264         /* The entries (hang off end: not really an array). */
 265         struct ipt_entry entries[0];
 266 };
 267
 268 /* The argument to IPT_SO_ADD_COUNTERS. */
 269 struct ipt_counters_info
 270 {
 271         /* Which table. */
 272         char name[IPT_TABLE_MAXNAMELEN];
 273
 274         unsigned int num_counters;
 275
 276         /* The counters (actually `number' of these). */
 277         struct ipt_counters counters[0];
 278 };
 279
 280 /* The argument to IPT_SO_GET_ENTRIES. */
 281 struct ipt_get_entries
 282 {
 283         /* Which table: user fills this in. */
 284         char name[IPT_TABLE_MAXNAMELEN];
 285
 286         /* User fills this in: total entry size. */
 287         unsigned int size;
 288
 289         /* The entries. */
 290         struct ipt_entry entrytable[0];
 291 };
 292
 293 /* The argument to IPT_SO_GET_REVISION_*.  Returns highest revision
 294  * kernel supports, if >= revision. */
 295 struct ipt_get_revision
 296 {
 297         char name[IPT_FUNCTION_MAXNAMELEN-1];
 298
 299         u_int8_t revision;
 300 };
 301
 302 /* Standard return verdict, or do jump. */
 303 #define IPT_STANDARD_TARGET ""
 304 /* Error verdict. */
 305 #define IPT_ERROR_TARGET "ERROR"
 306
 307 /* Helper functions */
 308 static __inline__ struct ipt_entry_target *
 309 ipt_get_target(struct ipt_entry *e)
 310 {
 311         return (void *)e + e->target_offset;
 312 }
 313
 314 /* fn returns 0 to continue iteration */
 315 #define IPT_MATCH_ITERATE(e, fn, args...)       \
 316 ({                                              \
 317         unsigned int __i;                       \
 318         int __ret = 0;                          \
 319         struct ipt_entry_match *__match;        \
 320                                                 \
 321         for (__i = sizeof(struct ipt_entry);    \
 322              __i < (e)->target_offset;          \
 323              __i += __match->u.match_size) {    \
 324                 __match = (void *)(e) + __i;    \
 325                                                 \
 326                 __ret = fn(__match , ## args);  \
 327                 if (__ret != 0)                 \
 328                         break;                  \
 329         }                                       \
 330         __ret;                                  \
 331 })
 332
 333 /* fn returns 0 to continue iteration */
 334 #define IPT_ENTRY_ITERATE(entries, size, fn, args...)           \
 335 ({                                                              \
 336         unsigned int __i;                                       \
 337         int __ret = 0;                                          \
 338         struct ipt_entry *__entry;                              \
 339                                                                 \
 340         for (__i = 0; __i < (size); __i += __entry->next_offset) { \
 341                 __entry = (void *)(entries) + __i;              \
 342                                                                 \
 343                 __ret = fn(__entry , ## args);                  \
 344                 if (__ret != 0)                                 \
 345                         break;                                  \
 346         }                                                       \
 347         __ret;                                                  \
 348 })
 349
 350 /*
 351  *      Main firewall chains definitions and global var's definitions.
 352  */
 353 #ifdef __KERNEL__
 354
 355 #include <linux/init.h>
 356 extern void ipt_init(void) __init;
 357
 358 struct ipt_match
 359 {
 360         struct list_head list;
 361
 362         const char name[IPT_FUNCTION_MAXNAMELEN-1];
 363
 364         u_int8_t revision;
 365
 366         /* Return true or false: return FALSE and set *hotdrop = 1 to
 367            force immediate packet drop. */
 368         /* Arguments changed since 2.4, as this must now handle
 369            non-linear skbs, using skb_copy_bits and
 370            skb_ip_make_writable. */
 371         int (*match)(const struct sk_buff *skb,
 372                      const struct net_device *in,
 373                      const struct net_device *out,
 374                      const void *matchinfo,
 375                      int offset,
 376                      int *hotdrop);
 377
 378         /* Called when user tries to insert an entry of this type. */
 379         /* Should return true or false. */
 380         int (*checkentry)(const char *tablename,
 381                           const struct ipt_ip *ip,
 382                           void *matchinfo,
 383                           unsigned int matchinfosize,
 384                           unsigned int hook_mask);
 385
 386         /* Called when entry of this type deleted. */
 387         void (*destroy)(void *matchinfo, unsigned int matchinfosize);
 388
 389         /* Set this to THIS_MODULE. */
 390         struct module *me;
 391 };
 392
 393 /* Registration hooks for targets. */
 394 struct ipt_target
 395 {
 396         struct list_head list;
 397
 398         const char name[IPT_FUNCTION_MAXNAMELEN-1];
 399
 400         u_int8_t revision;
 401
 402         /* Called when user tries to insert an entry of this type:
 403            hook_mask is a bitmask of hooks from which it can be
 404            called. */
 405         /* Should return true or false. */
 406         int (*checkentry)(const char *tablename,
 407                           const struct ipt_entry *e,
 408                           void *targinfo,
 409                           unsigned int targinfosize,
 410                           unsigned int hook_mask);
 411
 412         /* Called when entry of this type deleted. */
 413         void (*destroy)(void *targinfo, unsigned int targinfosize);
 414
 415         /* Returns verdict.  Argument order changed since 2.4, as this
 416            must now handle non-linear skbs, using skb_copy_bits and
 417            skb_ip_make_writable. */
 418         unsigned int (*target)(struct sk_buff **pskb,
 419                                const struct net_device *in,
 420                                const struct net_device *out,
 421                                unsigned int hooknum,
 422                                const void *targinfo,
 423                                void *userdata);
 424
 425         /* Set this to THIS_MODULE. */
 426         struct module *me;
 427 };
 428
 429 extern int ipt_register_target(struct ipt_target *target);
 430 extern void ipt_unregister_target(struct ipt_target *target);
 431
 432 extern int ipt_register_match(struct ipt_match *match);
 433 extern void ipt_unregister_match(struct ipt_match *match);
 434
 435 /* Furniture shopping... */
 436 struct ipt_table
 437 {
 438         struct list_head list;
 439
 440         /* A unique name... */
 441         char name[IPT_TABLE_MAXNAMELEN];
 442
 443         /* What hooks you will enter on */
 444         unsigned int valid_hooks;
 445
 446         /* Lock for the curtain */
 447         rwlock_t lock;
 448
 449         /* Man behind the curtain... */
 450         struct ipt_table_info *private;
 451
 452         /* Set to THIS_MODULE. */
 453         struct module *me;
 454 };
 455
 456 /* net/sched/ipt.c: Gimme access to your targets!  Gets target->me. */
 457 extern struct ipt_target *ipt_find_target(const char *name, u8 revision);
 458
 459 /* Standard entry. */
 460 struct ipt_standard
 461 {
 462         struct ipt_entry entry;
 463         struct ipt_standard_target target;
 464 };
 465
 466 struct ipt_error_target
 467 {
 468         struct ipt_entry_target target;
 469         char errorname[IPT_FUNCTION_MAXNAMELEN];
 470 };
 471
 472 struct ipt_error
 473 {
 474         struct ipt_entry entry;
 475         struct ipt_error_target target;
 476 };
 477
 478 extern int ipt_register_table(struct ipt_table *table,
 479                               const struct ipt_replace *repl);
 480 extern void ipt_unregister_table(struct ipt_table *table);
 481 extern unsigned int ipt_do_table(struct sk_buff **pskb,
 482                                  unsigned int hook,
 483                                  const struct net_device *in,
 484                                  const struct net_device *out,
 485                                  struct ipt_table *table,
 486                                  void *userdata);
 487
 488 #define IPT_ALIGN(s) (((s) + (__alignof__(struct ipt_entry)-1)) & ~(__alignof__(struct ipt_entry)-1))
 489 #endif /*__KERNEL__*/
 490 #endif /* _IPTABLES_H */