release/src/linux/linux/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/netfilter_ipv4.h>
  26
  27 #define IPT_FUNCTION_MAXNAMELEN 30
  28 #define IPT_TABLE_MAXNAMELEN 32
  29
  30 /* Yes, Virginia, you have to zero the padding. */
  31 struct ipt_ip {
  32         /* Source and destination IP addr */
  33         struct in_addr src, dst;
  34         /* Mask for src and dest IP addr */
  35         struct in_addr smsk, dmsk;
  36         char iniface[IFNAMSIZ], outiface[IFNAMSIZ];
  37         unsigned char iniface_mask[IFNAMSIZ], outiface_mask[IFNAMSIZ];
  38
  39         /* Protocol, 0 = ANY */
  40         u_int16_t proto;
  41
  42         /* Flags word */
  43         u_int8_t flags;
  44         /* Inverse flags */
  45         u_int8_t invflags;
  46 };
  47
  48 struct ipt_entry_match
  49 {
  50         union {
  51                 struct {
  52                         u_int16_t match_size;
  53
  54                         /* Used by userspace */
  55                         char name[IPT_FUNCTION_MAXNAMELEN];
  56                 } user;
  57                 struct {
  58                         u_int16_t match_size;
  59
  60                         /* Used inside the kernel */
  61                         struct ipt_match *match;
  62                 } kernel;
  63
  64                 /* Total length */
  65                 u_int16_t match_size;
  66         } u;
  67
  68         unsigned char data[0];
  69 };
  70
  71 struct ipt_entry_target
  72 {
  73         union {
  74                 struct {
  75                         u_int16_t target_size;
  76
  77                         /* Used by userspace */
  78                         char name[IPT_FUNCTION_MAXNAMELEN];
  79                 } user;
  80                 struct {
  81                         u_int16_t target_size;
  82
  83                         /* Used inside the kernel */
  84                         struct ipt_target *target;
  85                 } kernel;
  86
  87                 /* Total length */
  88                 u_int16_t target_size;
  89         } u;
  90
  91         unsigned char data[0];
  92 };
  93
  94 struct ipt_standard_target
  95 {
  96         struct ipt_entry_target target;
  97         int verdict;
  98 };
  99
 100 struct ipt_counters
 101 {
 102         u_int64_t pcnt, bcnt;                   /* Packet and byte counters */
 103 };
 104
 105 /* Values for "flag" field in struct ipt_ip (general ip structure). */
 106 #define IPT_F_FRAG              0x01    /* Set if rule is a fragment rule */
 107 #define IPT_F_GOTO              0x02    /* Set if jump is a goto */
 108 #define IPT_F_MASK              0x03    /* All possible flag bits mask. */
 109 #define IPT_F_NO_DEF_MATCH      0x80    /* Internal: no default match rules present */
 110
 111 /* Values for "inv" field in struct ipt_ip. */
 112 #define IPT_INV_VIA_IN          0x01    /* Invert the sense of IN IFACE. */
 113 #define IPT_INV_VIA_OUT         0x02    /* Invert the sense of OUT IFACE */
 114 #define IPT_INV_TOS             0x04    /* Invert the sense of TOS. */
 115 #define IPT_INV_SRCIP           0x08    /* Invert the sense of SRC IP. */
 116 #define IPT_INV_DSTIP           0x10    /* Invert the sense of DST OP. */
 117 #define IPT_INV_FRAG            0x20    /* Invert the sense of FRAG. */
 118 #define IPT_INV_PROTO           0x40    /* Invert the sense of PROTO. */
 119 #define IPT_INV_MASK            0x7F    /* All possible flag bits mask. */
 120
 121 /* This structure defines each of the firewall rules.  Consists of 3
 122    parts which are 1) general IP header stuff 2) match specific
 123    stuff 3) the target to perform if the rule matches */
 124 struct ipt_entry
 125 {
 126         struct ipt_ip ip;
 127
 128         /* Mark with fields that we care about. */
 129         unsigned int nfcache;
 130
 131         /* Size of ipt_entry + matches */
 132         u_int16_t target_offset;
 133         /* Size of ipt_entry + matches + target */
 134         u_int16_t next_offset;
 135
 136         /* Back pointer */
 137         unsigned int comefrom;
 138
 139         /* Packet and byte counters. */
 140         struct ipt_counters counters;
 141
 142         /* The matches (if any), then the target. */
 143         unsigned char elems[0];
 144 };
 145
 146 /*
 147  * New IP firewall options for [gs]etsockopt at the RAW IP level.
 148  * Unlike BSD Linux inherits IP options so you don't have to use a raw
 149  * socket for this. Instead we check rights in the calls. */
 150 #define IPT_BASE_CTL            64      /* base for firewall socket options */
 151
 152 #define IPT_SO_SET_REPLACE      (IPT_BASE_CTL)
 153 #define IPT_SO_SET_ADD_COUNTERS (IPT_BASE_CTL + 1)
 154 #define IPT_SO_SET_MAX          IPT_SO_SET_ADD_COUNTERS
 155
 156 #define IPT_SO_GET_INFO         (IPT_BASE_CTL)
 157 #define IPT_SO_GET_ENTRIES      (IPT_BASE_CTL + 1)
 158 #define IPT_SO_GET_MAX          IPT_SO_GET_ENTRIES
 159
 160 /* CONTINUE verdict for targets */
 161 #define IPT_CONTINUE 0xFFFFFFFF
 162
 163 /* For standard target */
 164 #define IPT_RETURN (-NF_MAX_VERDICT - 1)
 165
 166 /* TCP matching stuff */
 167 struct ipt_tcp
 168 {
 169         u_int16_t spts[2];                      /* Source port range. */
 170         u_int16_t dpts[2];                      /* Destination port range. */
 171         u_int8_t option;                        /* TCP Option iff non-zero*/
 172         u_int8_t flg_mask;                      /* TCP flags mask byte */
 173         u_int8_t flg_cmp;                       /* TCP flags compare byte */
 174         u_int8_t invflags;                      /* Inverse flags */
 175 };
 176
 177 /* Values for "inv" field in struct ipt_tcp. */
 178 #define IPT_TCP_INV_SRCPT       0x01    /* Invert the sense of source ports. */
 179 #define IPT_TCP_INV_DSTPT       0x02    /* Invert the sense of dest ports. */
 180 #define IPT_TCP_INV_FLAGS       0x04    /* Invert the sense of TCP flags. */
 181 #define IPT_TCP_INV_OPTION      0x08    /* Invert the sense of option test. */
 182 #define IPT_TCP_INV_MASK        0x0F    /* All possible flags. */
 183
 184 /* UDP matching stuff */
 185 struct ipt_udp
 186 {
 187         u_int16_t spts[2];                      /* Source port range. */
 188         u_int16_t dpts[2];                      /* Destination port range. */
 189         u_int8_t invflags;                      /* Inverse flags */
 190 };
 191
 192 /* Values for "invflags" field in struct ipt_udp. */
 193 #define IPT_UDP_INV_SRCPT       0x01    /* Invert the sense of source ports. */
 194 #define IPT_UDP_INV_DSTPT       0x02    /* Invert the sense of dest ports. */
 195 #define IPT_UDP_INV_MASK        0x03    /* All possible flags. */
 196
 197 /* ICMP matching stuff */
 198 struct ipt_icmp
 199 {
 200         u_int8_t type;                          /* type to match */
 201         u_int8_t code[2];                       /* range of code */
 202         u_int8_t invflags;                      /* Inverse flags */
 203 };
 204
 205 /* Values for "inv" field for struct ipt_icmp. */
 206 #define IPT_ICMP_INV    0x01    /* Invert the sense of type/code test */
 207
 208 /* The argument to IPT_SO_GET_INFO */
 209 struct ipt_getinfo
 210 {
 211         /* Which table: caller fills this in. */
 212         char name[IPT_TABLE_MAXNAMELEN];
 213
 214         /* Kernel fills these in. */
 215         /* Which hook entry points are valid: bitmask */
 216         unsigned int valid_hooks;
 217
 218         /* Hook entry points: one per netfilter hook. */
 219         unsigned int hook_entry[NF_IP_NUMHOOKS];
 220
 221         /* Underflow points. */
 222         unsigned int underflow[NF_IP_NUMHOOKS];
 223
 224         /* Number of entries */
 225         unsigned int num_entries;
 226
 227         /* Size of entries. */
 228         unsigned int size;
 229 };
 230
 231 /* The argument to IPT_SO_SET_REPLACE. */
 232 struct ipt_replace
 233 {
 234         /* Which table. */
 235         char name[IPT_TABLE_MAXNAMELEN];
 236
 237         /* Which hook entry points are valid: bitmask.  You can't
 238            change this. */
 239         unsigned int valid_hooks;
 240
 241         /* Number of entries */
 242         unsigned int num_entries;
 243
 244         /* Total size of new entries */
 245         unsigned int size;
 246
 247         /* Hook entry points. */
 248         unsigned int hook_entry[NF_IP_NUMHOOKS];
 249
 250         /* Underflow points. */
 251         unsigned int underflow[NF_IP_NUMHOOKS];
 252
 253         /* Information about old entries: */
 254         /* Number of counters (must be equal to current number of entries). */
 255         unsigned int num_counters;
 256         /* The old entries' counters. */
 257         struct ipt_counters *counters;
 258
 259         /* The entries (hang off end: not really an array). */
 260         struct ipt_entry entries[0];
 261 };
 262
 263 /* The argument to IPT_SO_ADD_COUNTERS. */
 264 struct ipt_counters_info
 265 {
 266         /* Which table. */
 267         char name[IPT_TABLE_MAXNAMELEN];
 268
 269         unsigned int num_counters;
 270
 271         /* The counters (actually `number' of these). */
 272         struct ipt_counters counters[0];
 273 };
 274
 275 /* The argument to IPT_SO_GET_ENTRIES. */
 276 struct ipt_get_entries
 277 {
 278         /* Which table: user fills this in. */
 279         char name[IPT_TABLE_MAXNAMELEN];
 280
 281         /* User fills this in: total entry size. */
 282         unsigned int size;
 283
 284         /* The entries. */
 285         struct ipt_entry entrytable[0];
 286 };
 287
 288 /* Standard return verdict, or do jump. */
 289 #define IPT_STANDARD_TARGET ""
 290 /* Error verdict. */
 291 #define IPT_ERROR_TARGET "ERROR"
 292
 293 /* Helper functions */
 294 static __inline__ struct ipt_entry_target *
 295 ipt_get_target(struct ipt_entry *e)
 296 {
 297         return (void *)e + e->target_offset;
 298 }
 299
 300 /* fn returns 0 to continue iteration */
 301 #define IPT_MATCH_ITERATE(e, fn, args...)       \
 302 ({                                              \
 303         unsigned int __i;                       \
 304         int __ret = 0;                          \
 305         struct ipt_entry_match *__match;        \
 306                                                 \
 307         for (__i = sizeof(struct ipt_entry);    \
 308              __i < (e)->target_offset;          \
 309              __i += __match->u.match_size) {    \
 310                 __match = (void *)(e) + __i;    \
 311                                                 \
 312                 __ret = fn(__match , ## args);  \
 313                 if (__ret != 0)                 \
 314                         break;                  \
 315         }                                       \
 316         __ret;                                  \
 317 })
 318
 319 /* fn returns 0 to continue iteration */
 320 #define IPT_ENTRY_ITERATE(entries, size, fn, args...)           \
 321 ({                                                              \
 322         unsigned int __i;                                       \
 323         int __ret = 0;                                          \
 324         struct ipt_entry *__entry;                              \
 325                                                                 \
 326         for (__i = 0; __i < (size); __i += __entry->next_offset) { \
 327                 __entry = (void *)(entries) + __i;              \
 328                                                                 \
 329                 __ret = fn(__entry , ## args);                  \
 330                 if (__ret != 0)                                 \
 331                         break;                                  \
 332         }                                                       \
 333         __ret;                                                  \
 334 })
 335
 336 /*
 337  *      Main firewall chains definitions and global var's definitions.
 338  */
 339 #ifdef __KERNEL__
 340
 341 #include <linux/init.h>
 342 extern void ipt_init(void) __init;
 343
 344 struct ipt_match
 345 {
 346         struct list_head list;
 347
 348         const char name[IPT_FUNCTION_MAXNAMELEN];
 349
 350         /* Return true or false: return FALSE and set *hotdrop = 1 to
 351            force immediate packet drop. */
 352         int (*match)(const struct sk_buff *skb,
 353                      const struct net_device *in,
 354                      const struct net_device *out,
 355                      const void *matchinfo,
 356                      int offset,
 357                      const void *hdr,
 358                      u_int16_t datalen,
 359                      int *hotdrop);
 360
 361         /* Called when user tries to insert an entry of this type. */
 362         /* Should return true or false. */
 363         int (*checkentry)(const char *tablename,
 364                           const struct ipt_ip *ip,
 365                           void *matchinfo,
 366                           unsigned int matchinfosize,
 367                           unsigned int hook_mask);
 368
 369         /* Called when entry of this type deleted. */
 370         void (*destroy)(void *matchinfo, unsigned int matchinfosize);
 371
 372         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 373         struct module *me;
 374 };
 375
 376 /* Registration hooks for targets. */
 377 struct ipt_target
 378 {
 379         struct list_head list;
 380
 381         const char name[IPT_FUNCTION_MAXNAMELEN];
 382
 383         /* Returns verdict. */
 384         unsigned int (*target)(struct sk_buff **pskb,
 385                                unsigned int hooknum,
 386                                const struct net_device *in,
 387                                const struct net_device *out,
 388                                const void *targinfo,
 389                                void *userdata);
 390
 391         /* Called when user tries to insert an entry of this type:
 392            hook_mask is a bitmask of hooks from which it can be
 393            called. */
 394         /* Should return true or false. */
 395         int (*checkentry)(const char *tablename,
 396                           const struct ipt_entry *e,
 397                           void *targinfo,
 398                           unsigned int targinfosize,
 399                           unsigned int hook_mask);
 400
 401         /* Called when entry of this type deleted. */
 402         void (*destroy)(void *targinfo, unsigned int targinfosize);
 403
 404         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 405         struct module *me;
 406 };
 407
 408 extern struct ipt_target *
 409 ipt_find_target_lock(const char *name, int *error, struct semaphore *mutex);
 410 extern struct arpt_target *
 411 arpt_find_target_lock(const char *name, int *error, struct semaphore *mutex);
 412
 413 extern int ipt_register_target(struct ipt_target *target);
 414 extern void ipt_unregister_target(struct ipt_target *target);
 415
 416 extern int ipt_register_match(struct ipt_match *match);
 417 extern void ipt_unregister_match(struct ipt_match *match);
 418
 419 /* Furniture shopping... */
 420 struct ipt_table
 421 {
 422         struct list_head list;
 423
 424         /* A unique name... */
 425         char name[IPT_TABLE_MAXNAMELEN];
 426
 427         /* Seed table: copied in register_table */
 428         struct ipt_replace *table;
 429
 430         /* What hooks you will enter on */
 431         unsigned int valid_hooks;
 432
 433         /* Lock for the curtain */
 434         rwlock_t lock;
 435
 436         /* Man behind the curtain... */
 437         struct ipt_table_info *private;
 438
 439         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
 440         struct module *me;
 441 };
 442
 443 extern int ipt_register_table(struct ipt_table *table);
 444 extern void ipt_unregister_table(struct ipt_table *table);
 445 extern unsigned int ipt_do_table(struct sk_buff **pskb,
 446                                  unsigned int hook,
 447                                  const struct net_device *in,
 448                                  const struct net_device *out,
 449                                  struct ipt_table *table,
 450                                  void *userdata);
 451
 452 #define IPT_ALIGN(s) (((s) + (__alignof__(struct ipt_entry)-1)) & ~(__alignof__(struct ipt_entry)-1))
 453 #endif /*__KERNEL__*/
 454 #endif /* _IPTABLES_H */