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