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