include/linux/netfilter_bridge/ebtables.h

   1 /*
   2  *  ebtables
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer                <bdschuym@pandora.be>
   6  *
   7  *  ebtables.c,v 2.0, April, 2002
   8  *
   9  *  This code is stongly inspired on the iptables code which is
  10  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  11  */
  12
  13 #ifndef __LINUX_BRIDGE_EFF_H
  14 #define __LINUX_BRIDGE_EFF_H
  15 #include <linux/if.h>
  16 #include <linux/netfilter_bridge.h>
  17 #include <linux/if_ether.h>
  18
  19 #define EBT_TABLE_MAXNAMELEN 32
  20 #define EBT_CHAIN_MAXNAMELEN EBT_TABLE_MAXNAMELEN
  21 #define EBT_FUNCTION_MAXNAMELEN EBT_TABLE_MAXNAMELEN
  22
  23 /* verdicts >0 are "branches" */
  24 #define EBT_ACCEPT   -1
  25 #define EBT_DROP     -2
  26 #define EBT_CONTINUE -3
  27 #define EBT_RETURN   -4
  28 #define NUM_STANDARD_TARGETS   4
  29 /* ebtables target modules store the verdict inside an int. We can
  30  * reclaim a part of this int for backwards compatible extensions.
  31  * The 4 lsb are more than enough to store the verdict. */
  32 #define EBT_VERDICT_BITS 0x0000000F
  33
  34 struct xt_match;
  35 struct xt_target;
  36
  37 struct ebt_counter
  38 {
  39         uint64_t pcnt;
  40         uint64_t bcnt;
  41 };
  42
  43 struct ebt_replace
  44 {
  45         char name[EBT_TABLE_MAXNAMELEN];
  46         unsigned int valid_hooks;
  47         /* nr of rules in the table */
  48         unsigned int nentries;
  49         /* total size of the entries */
  50         unsigned int entries_size;
  51         /* start of the chains */
  52         struct ebt_entries __user *hook_entry[NF_BR_NUMHOOKS];
  53         /* nr of counters userspace expects back */
  54         unsigned int num_counters;
  55         /* where the kernel will put the old counters */
  56         struct ebt_counter __user *counters;
  57         char __user *entries;
  58 };
  59
  60 struct ebt_replace_kernel
  61 {
  62         char name[EBT_TABLE_MAXNAMELEN];
  63         unsigned int valid_hooks;
  64         /* nr of rules in the table */
  65         unsigned int nentries;
  66         /* total size of the entries */
  67         unsigned int entries_size;
  68         /* start of the chains */
  69         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
  70         /* nr of counters userspace expects back */
  71         unsigned int num_counters;
  72         /* where the kernel will put the old counters */
  73         struct ebt_counter *counters;
  74         char *entries;
  75 };
  76
  77 struct ebt_entries {
  78         /* this field is always set to zero
  79          * See EBT_ENTRY_OR_ENTRIES.
  80          * Must be same size as ebt_entry.bitmask */
  81         unsigned int distinguisher;
  82         /* the chain name */
  83         char name[EBT_CHAIN_MAXNAMELEN];
  84         /* counter offset for this chain */
  85         unsigned int counter_offset;
  86         /* one standard (accept, drop, return) per hook */
  87         int policy;
  88         /* nr. of entries */
  89         unsigned int nentries;
  90         /* entry list */
  91         char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
  92 };
  93
  94 /* used for the bitmask of struct ebt_entry */
  95
  96 /* This is a hack to make a difference between an ebt_entry struct and an
  97  * ebt_entries struct when traversing the entries from start to end.
  98  * Using this simplifies the code alot, while still being able to use
  99  * ebt_entries.
 100  * Contrary, iptables doesn't use something like ebt_entries and therefore uses
 101  * different techniques for naming the policy and such. So, iptables doesn't
 102  * need a hack like this.
 103  */
 104 #define EBT_ENTRY_OR_ENTRIES 0x01
 105 /* these are the normal masks */
 106 #define EBT_NOPROTO 0x02
 107 #define EBT_802_3 0x04
 108 #define EBT_SOURCEMAC 0x08
 109 #define EBT_DESTMAC 0x10
 110 #define EBT_F_MASK (EBT_NOPROTO | EBT_802_3 | EBT_SOURCEMAC | EBT_DESTMAC \
 111    | EBT_ENTRY_OR_ENTRIES)
 112
 113 #define EBT_IPROTO 0x01
 114 #define EBT_IIN 0x02
 115 #define EBT_IOUT 0x04
 116 #define EBT_ISOURCE 0x8
 117 #define EBT_IDEST 0x10
 118 #define EBT_ILOGICALIN 0x20
 119 #define EBT_ILOGICALOUT 0x40
 120 #define EBT_INV_MASK (EBT_IPROTO | EBT_IIN | EBT_IOUT | EBT_ILOGICALIN \
 121    | EBT_ILOGICALOUT | EBT_ISOURCE | EBT_IDEST)
 122
 123 struct ebt_entry_match
 124 {
 125         union {
 126                 char name[EBT_FUNCTION_MAXNAMELEN];
 127                 struct xt_match *match;
 128         } u;
 129         /* size of data */
 130         unsigned int match_size;
 131         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 132 };
 133
 134 struct ebt_entry_watcher
 135 {
 136         union {
 137                 char name[EBT_FUNCTION_MAXNAMELEN];
 138                 struct xt_target *watcher;
 139         } u;
 140         /* size of data */
 141         unsigned int watcher_size;
 142         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 143 };
 144
 145 struct ebt_entry_target
 146 {
 147         union {
 148                 char name[EBT_FUNCTION_MAXNAMELEN];
 149                 struct xt_target *target;
 150         } u;
 151         /* size of data */
 152         unsigned int target_size;
 153         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 154 };
 155
 156 #define EBT_STANDARD_TARGET "standard"
 157 struct ebt_standard_target
 158 {
 159         struct ebt_entry_target target;
 160         int verdict;
 161 };
 162
 163 /* one entry */
 164 struct ebt_entry {
 165         /* this needs to be the first field */
 166         unsigned int bitmask;
 167         unsigned int invflags;
 168         __be16 ethproto;
 169         /* the physical in-dev */
 170         char in[IFNAMSIZ];
 171         /* the logical in-dev */
 172         char logical_in[IFNAMSIZ];
 173         /* the physical out-dev */
 174         char out[IFNAMSIZ];
 175         /* the logical out-dev */
 176         char logical_out[IFNAMSIZ];
 177         unsigned char sourcemac[ETH_ALEN];
 178         unsigned char sourcemsk[ETH_ALEN];
 179         unsigned char destmac[ETH_ALEN];
 180         unsigned char destmsk[ETH_ALEN];
 181         /* sizeof ebt_entry + matches */
 182         unsigned int watchers_offset;
 183         /* sizeof ebt_entry + matches + watchers */
 184         unsigned int target_offset;
 185         /* sizeof ebt_entry + matches + watchers + target */
 186         unsigned int next_offset;
 187         unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 188 };
 189
 190 /* {g,s}etsockopt numbers */
 191 #define EBT_BASE_CTL            128
 192
 193 #define EBT_SO_SET_ENTRIES      (EBT_BASE_CTL)
 194 #define EBT_SO_SET_COUNTERS     (EBT_SO_SET_ENTRIES+1)
 195 #define EBT_SO_SET_MAX          (EBT_SO_SET_COUNTERS+1)
 196
 197 #define EBT_SO_GET_INFO         (EBT_BASE_CTL)
 198 #define EBT_SO_GET_ENTRIES      (EBT_SO_GET_INFO+1)
 199 #define EBT_SO_GET_INIT_INFO    (EBT_SO_GET_ENTRIES+1)
 200 #define EBT_SO_GET_INIT_ENTRIES (EBT_SO_GET_INIT_INFO+1)
 201 #define EBT_SO_GET_MAX          (EBT_SO_GET_INIT_ENTRIES+1)
 202
 203 #ifdef __KERNEL__
 204
 205 /* return values for match() functions */
 206 #define EBT_MATCH 0
 207 #define EBT_NOMATCH 1
 208
 209 struct ebt_match
 210 {
 211         struct list_head list;
 212         const char name[EBT_FUNCTION_MAXNAMELEN];
 213         bool (*match)(const struct sk_buff *skb, const struct net_device *in,
 214                 const struct net_device *out, const struct xt_match *match,
 215                 const void *matchinfo, int offset, unsigned int protoff,
 216                 bool *hotdrop);
 217         bool (*checkentry)(const char *table, const void *entry,
 218                 const struct xt_match *match, void *matchinfo,
 219                 unsigned int hook_mask);
 220         void (*destroy)(const struct xt_match *match, void *matchinfo);
 221         unsigned int matchsize;
 222         u_int8_t revision;
 223         u_int8_t family;
 224         struct module *me;
 225 };
 226
 227 struct ebt_watcher
 228 {
 229         struct list_head list;
 230         const char name[EBT_FUNCTION_MAXNAMELEN];
 231         unsigned int (*target)(struct sk_buff *skb,
 232                 const struct net_device *in, const struct net_device *out,
 233                 unsigned int hook_num, const struct xt_target *target,
 234                 const void *targinfo);
 235         bool (*checkentry)(const char *table, const void *entry,
 236                 const struct xt_target *target, void *targinfo,
 237                 unsigned int hook_mask);
 238         void (*destroy)(const struct xt_target *target, void *targinfo);
 239         unsigned int targetsize;
 240         u_int8_t revision;
 241         u_int8_t family;
 242         struct module *me;
 243 };
 244
 245 struct ebt_target
 246 {
 247         struct list_head list;
 248         const char name[EBT_FUNCTION_MAXNAMELEN];
 249         /* returns one of the standard EBT_* verdicts */
 250         unsigned int (*target)(struct sk_buff *skb,
 251                 const struct net_device *in, const struct net_device *out,
 252                 unsigned int hook_num, const struct xt_target *target,
 253                 const void *targinfo);
 254         bool (*checkentry)(const char *table, const void *entry,
 255                 const struct xt_target *target, void *targinfo,
 256                 unsigned int hook_mask);
 257         void (*destroy)(const struct xt_target *target, void *targinfo);
 258         unsigned int targetsize;
 259         u_int8_t revision;
 260         u_int8_t family;
 261         struct module *me;
 262 };
 263
 264 /* used for jumping from and into user defined chains (udc) */
 265 struct ebt_chainstack
 266 {
 267         struct ebt_entries *chaininfo; /* pointer to chain data */
 268         struct ebt_entry *e; /* pointer to entry data */
 269         unsigned int n; /* n'th entry */
 270 };
 271
 272 struct ebt_table_info
 273 {
 274         /* total size of the entries */
 275         unsigned int entries_size;
 276         unsigned int nentries;
 277         /* pointers to the start of the chains */
 278         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
 279         /* room to maintain the stack used for jumping from and into udc */
 280         struct ebt_chainstack **chainstack;
 281         char *entries;
 282         struct ebt_counter counters[0] ____cacheline_aligned;
 283 };
 284
 285 struct ebt_table
 286 {
 287         struct list_head list;
 288         char name[EBT_TABLE_MAXNAMELEN];
 289         struct ebt_replace_kernel *table;
 290         unsigned int valid_hooks;
 291         rwlock_t lock;
 292         /* e.g. could be the table explicitly only allows certain
 293          * matches, targets, ... 0 == let it in */
 294         int (*check)(const struct ebt_table_info *info,
 295            unsigned int valid_hooks);
 296         /* the data used by the kernel */
 297         struct ebt_table_info *private;
 298         struct module *me;
 299 };
 300
 301 #define EBT_ALIGN(s) (((s) + (__alignof__(struct ebt_replace)-1)) & \
 302                      ~(__alignof__(struct ebt_replace)-1))
 303 extern int ebt_register_table(struct ebt_table *table);
 304 extern void ebt_unregister_table(struct ebt_table *table);
 305 extern int ebt_register_match(struct ebt_match *match);
 306 extern void ebt_unregister_match(struct ebt_match *match);
 307 extern int ebt_register_watcher(struct ebt_watcher *watcher);
 308 extern void ebt_unregister_watcher(struct ebt_watcher *watcher);
 309 extern int ebt_register_target(struct ebt_target *target);
 310 extern void ebt_unregister_target(struct ebt_target *target);
 311 extern unsigned int ebt_do_table(unsigned int hook, struct sk_buff *skb,
 312    const struct net_device *in, const struct net_device *out,
 313    struct ebt_table *table);
 314
 315 /* Used in the kernel match() functions */
 316 #define FWINV(bool,invflg) ((bool) ^ !!(info->invflags & invflg))
 317 /* True if the hook mask denotes that the rule is in a base chain,
 318  * used in the check() functions */
 319 #define BASE_CHAIN (hookmask & (1 << NF_BR_NUMHOOKS))
 320 /* Clear the bit in the hook mask that tells if the rule is on a base chain */
 321 #define CLEAR_BASE_CHAIN_BIT (hookmask &= ~(1 << NF_BR_NUMHOOKS))
 322 /* True if the target is not a standard target */
 323 #define INVALID_TARGET (info->target < -NUM_STANDARD_TARGETS || info->target >= 0)
 324
 325 #endif /* __KERNEL__ */
 326
 327 /* blatently stolen from ip_tables.h
 328  * fn returns 0 to continue iteration */
 329 #define EBT_MATCH_ITERATE(e, fn, args...)                   \
 330 ({                                                          \
 331         unsigned int __i;                                   \
 332         int __ret = 0;                                      \
 333         struct ebt_entry_match *__match;                    \
 334                                                             \
 335         for (__i = sizeof(struct ebt_entry);                \
 336              __i < (e)->watchers_offset;                    \
 337              __i += __match->match_size +                   \
 338              sizeof(struct ebt_entry_match)) {              \
 339                 __match = (void *)(e) + __i;                \
 340                                                             \
 341                 __ret = fn(__match , ## args);              \
 342                 if (__ret != 0)                             \
 343                         break;                              \
 344         }                                                   \
 345         if (__ret == 0) {                                   \
 346                 if (__i != (e)->watchers_offset)            \
 347                         __ret = -EINVAL;                    \
 348         }                                                   \
 349         __ret;                                              \
 350 })
 351
 352 #define EBT_WATCHER_ITERATE(e, fn, args...)                 \
 353 ({                                                          \
 354         unsigned int __i;                                   \
 355         int __ret = 0;                                      \
 356         struct ebt_entry_watcher *__watcher;                \
 357                                                             \
 358         for (__i = e->watchers_offset;                      \
 359              __i < (e)->target_offset;                      \
 360              __i += __watcher->watcher_size +               \
 361              sizeof(struct ebt_entry_watcher)) {            \
 362                 __watcher = (void *)(e) + __i;              \
 363                                                             \
 364                 __ret = fn(__watcher , ## args);            \
 365                 if (__ret != 0)                             \
 366                         break;                              \
 367         }                                                   \
 368         if (__ret == 0) {                                   \
 369                 if (__i != (e)->target_offset)              \
 370                         __ret = -EINVAL;                    \
 371         }                                                   \
 372         __ret;                                              \
 373 })
 374
 375 #define EBT_ENTRY_ITERATE(entries, size, fn, args...)       \
 376 ({                                                          \
 377         unsigned int __i;                                   \
 378         int __ret = 0;                                      \
 379         struct ebt_entry *__entry;                          \
 380                                                             \
 381         for (__i = 0; __i < (size);) {                      \
 382                 __entry = (void *)(entries) + __i;          \
 383                 __ret = fn(__entry , ## args);              \
 384                 if (__ret != 0)                             \
 385                         break;                              \
 386                 if (__entry->bitmask != 0)                  \
 387                         __i += __entry->next_offset;        \
 388                 else                                        \
 389                         __i += sizeof(struct ebt_entries);  \
 390         }                                                   \
 391         if (__ret == 0) {                                   \
 392                 if (__i != (size))                          \
 393                         __ret = -EINVAL;                    \
 394         }                                                   \
 395         __ret;                                              \
 396 })
 397
 398 #endif