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
  30 struct ebt_counter
  31 {
  32         uint64_t pcnt;
  33         uint64_t bcnt;
  34 };
  35
  36 struct ebt_replace
  37 {
  38         char name[EBT_TABLE_MAXNAMELEN];
  39         unsigned int valid_hooks;
  40         /* nr of rules in the table */
  41         unsigned int nentries;
  42         /* total size of the entries */
  43         unsigned int entries_size;
  44         /* start of the chains */
  45         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
  46         /* nr of counters userspace expects back */
  47         unsigned int num_counters;
  48         /* where the kernel will put the old counters */
  49         struct ebt_counter *counters;
  50         char *entries;
  51 };
  52
  53 struct ebt_entries {
  54         /* this field is always set to zero
  55          * See EBT_ENTRY_OR_ENTRIES.
  56          * Must be same size as ebt_entry.bitmask */
  57         unsigned int distinguisher;
  58         /* the chain name */
  59         char name[EBT_CHAIN_MAXNAMELEN];
  60         /* counter offset for this chain */
  61         unsigned int counter_offset;
  62         /* one standard (accept, drop, return) per hook */
  63         int policy;
  64         /* nr. of entries */
  65         unsigned int nentries;
  66         /* entry list */
  67         char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
  68 };
  69
  70 /* used for the bitmask of struct ebt_entry */
  71
  72 /* This is a hack to make a difference between an ebt_entry struct and an
  73  * ebt_entries struct when traversing the entries from start to end.
  74  * Using this simplifies the code alot, while still being able to use
  75  * ebt_entries.
  76  * Contrary, iptables doesn't use something like ebt_entries and therefore uses
  77  * different techniques for naming the policy and such. So, iptables doesn't
  78  * need a hack like this.
  79  */
  80 #define EBT_ENTRY_OR_ENTRIES 0x01
  81 /* these are the normal masks */
  82 #define EBT_NOPROTO 0x02
  83 #define EBT_802_3 0x04
  84 #define EBT_SOURCEMAC 0x08
  85 #define EBT_DESTMAC 0x10
  86 #define EBT_F_MASK (EBT_NOPROTO | EBT_802_3 | EBT_SOURCEMAC | EBT_DESTMAC \
  87    | EBT_ENTRY_OR_ENTRIES)
  88
  89 #define EBT_IPROTO 0x01
  90 #define EBT_IIN 0x02
  91 #define EBT_IOUT 0x04
  92 #define EBT_ISOURCE 0x8
  93 #define EBT_IDEST 0x10
  94 #define EBT_ILOGICALIN 0x20
  95 #define EBT_ILOGICALOUT 0x40
  96 #define EBT_INV_MASK (EBT_IPROTO | EBT_IIN | EBT_IOUT | EBT_ILOGICALIN \
  97    | EBT_ILOGICALOUT | EBT_ISOURCE | EBT_IDEST)
  98
  99 struct ebt_entry_match
 100 {
 101         union {
 102                 char name[EBT_FUNCTION_MAXNAMELEN];
 103                 struct ebt_match *match;
 104         } u;
 105         /* size of data */
 106         unsigned int match_size;
 107         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 108 };
 109
 110 struct ebt_entry_watcher
 111 {
 112         union {
 113                 char name[EBT_FUNCTION_MAXNAMELEN];
 114                 struct ebt_watcher *watcher;
 115         } u;
 116         /* size of data */
 117         unsigned int watcher_size;
 118         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 119 };
 120
 121 struct ebt_entry_target
 122 {
 123         union {
 124                 char name[EBT_FUNCTION_MAXNAMELEN];
 125                 struct ebt_target *target;
 126         } u;
 127         /* size of data */
 128         unsigned int target_size;
 129         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 130 };
 131
 132 #define EBT_STANDARD_TARGET "standard"
 133 struct ebt_standard_target
 134 {
 135         struct ebt_entry_target target;
 136         int verdict;
 137 };
 138
 139 /* one entry */
 140 struct ebt_entry {
 141         /* this needs to be the first field */
 142         unsigned int bitmask;
 143         unsigned int invflags;
 144         uint16_t ethproto;
 145         /* the physical in-dev */
 146         char in[IFNAMSIZ];
 147         /* the logical in-dev */
 148         char logical_in[IFNAMSIZ];
 149         /* the physical out-dev */
 150         char out[IFNAMSIZ];
 151         /* the logical out-dev */
 152         char logical_out[IFNAMSIZ];
 153         unsigned char sourcemac[ETH_ALEN];
 154         unsigned char sourcemsk[ETH_ALEN];
 155         unsigned char destmac[ETH_ALEN];
 156         unsigned char destmsk[ETH_ALEN];
 157         /* sizeof ebt_entry + matches */
 158         unsigned int watchers_offset;
 159         /* sizeof ebt_entry + matches + watchers */
 160         unsigned int target_offset;
 161         /* sizeof ebt_entry + matches + watchers + target */
 162         unsigned int next_offset;
 163         unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 164 };
 165
 166 /* {g,s}etsockopt numbers */
 167 #define EBT_BASE_CTL            128
 168
 169 #define EBT_SO_SET_ENTRIES      (EBT_BASE_CTL)
 170 #define EBT_SO_SET_COUNTERS     (EBT_SO_SET_ENTRIES+1)
 171 #define EBT_SO_SET_MAX          (EBT_SO_SET_COUNTERS+1)
 172
 173 #define EBT_SO_GET_INFO         (EBT_BASE_CTL)
 174 #define EBT_SO_GET_ENTRIES      (EBT_SO_GET_INFO+1)
 175 #define EBT_SO_GET_INIT_INFO    (EBT_SO_GET_ENTRIES+1)
 176 #define EBT_SO_GET_INIT_ENTRIES (EBT_SO_GET_INIT_INFO+1)
 177 #define EBT_SO_GET_MAX          (EBT_SO_GET_INIT_ENTRIES+1)
 178
 179 #ifdef __KERNEL__
 180
 181 /* return values for match() functions */
 182 #define EBT_MATCH 0
 183 #define EBT_NOMATCH 1
 184
 185 struct ebt_match
 186 {
 187         struct list_head list;
 188         const char name[EBT_FUNCTION_MAXNAMELEN];
 189         /* 0 == it matches */
 190         int (*match)(const struct sk_buff *skb, const struct net_device *in,
 191            const struct net_device *out, const void *matchdata,
 192            unsigned int datalen);
 193         /* 0 == let it in */
 194         int (*check)(const char *tablename, unsigned int hookmask,
 195            const struct ebt_entry *e, void *matchdata, unsigned int datalen);
 196         void (*destroy)(void *matchdata, unsigned int datalen);
 197         struct module *me;
 198 };
 199
 200 struct ebt_watcher
 201 {
 202         struct list_head list;
 203         const char name[EBT_FUNCTION_MAXNAMELEN];
 204         void (*watcher)(const struct sk_buff *skb, unsigned int hooknr,
 205            const struct net_device *in, const struct net_device *out,
 206            const void *watcherdata, unsigned int datalen);
 207         /* 0 == let it in */
 208         int (*check)(const char *tablename, unsigned int hookmask,
 209            const struct ebt_entry *e, void *watcherdata, unsigned int datalen);
 210         void (*destroy)(void *watcherdata, unsigned int datalen);
 211         struct module *me;
 212 };
 213
 214 struct ebt_target
 215 {
 216         struct list_head list;
 217         const char name[EBT_FUNCTION_MAXNAMELEN];
 218         /* returns one of the standard verdicts */
 219         int (*target)(struct sk_buff **pskb, unsigned int hooknr,
 220            const struct net_device *in, const struct net_device *out,
 221            const void *targetdata, unsigned int datalen);
 222         /* 0 == let it in */
 223         int (*check)(const char *tablename, unsigned int hookmask,
 224            const struct ebt_entry *e, void *targetdata, unsigned int datalen);
 225         void (*destroy)(void *targetdata, unsigned int datalen);
 226         struct module *me;
 227 };
 228
 229 /* used for jumping from and into user defined chains (udc) */
 230 struct ebt_chainstack
 231 {
 232         struct ebt_entries *chaininfo; /* pointer to chain data */
 233         struct ebt_entry *e; /* pointer to entry data */
 234         unsigned int n; /* n'th entry */
 235 };
 236
 237 struct ebt_table_info
 238 {
 239         /* total size of the entries */
 240         unsigned int entries_size;
 241         unsigned int nentries;
 242         /* pointers to the start of the chains */
 243         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
 244         /* room to maintain the stack used for jumping from and into udc */
 245         struct ebt_chainstack **chainstack;
 246         char *entries;
 247         struct ebt_counter counters[0] ____cacheline_aligned;
 248 };
 249
 250 struct ebt_table
 251 {
 252         struct list_head list;
 253         char name[EBT_TABLE_MAXNAMELEN];
 254         struct ebt_replace *table;
 255         unsigned int valid_hooks;
 256         rwlock_t lock;
 257         /* e.g. could be the table explicitly only allows certain
 258          * matches, targets, ... 0 == let it in */
 259         int (*check)(const struct ebt_table_info *info,
 260            unsigned int valid_hooks);
 261         /* the data used by the kernel */
 262         struct ebt_table_info *private;
 263         struct module *me;
 264 };
 265
 266 #define EBT_ALIGN(s) (((s) + (__alignof__(struct ebt_replace)-1)) & \
 267                      ~(__alignof__(struct ebt_replace)-1))
 268 extern int ebt_register_table(struct ebt_table *table);
 269 extern void ebt_unregister_table(struct ebt_table *table);
 270 extern int ebt_register_match(struct ebt_match *match);
 271 extern void ebt_unregister_match(struct ebt_match *match);
 272 extern int ebt_register_watcher(struct ebt_watcher *watcher);
 273 extern void ebt_unregister_watcher(struct ebt_watcher *watcher);
 274 extern int ebt_register_target(struct ebt_target *target);
 275 extern void ebt_unregister_target(struct ebt_target *target);
 276 extern unsigned int ebt_do_table(unsigned int hook, struct sk_buff **pskb,
 277    const struct net_device *in, const struct net_device *out,
 278    struct ebt_table *table);
 279
 280 /* Used in the kernel match() functions */
 281 #define FWINV(bool,invflg) ((bool) ^ !!(info->invflags & invflg))
 282 /* True if the hook mask denotes that the rule is in a base chain,
 283  * used in the check() functions */
 284 #define BASE_CHAIN (hookmask & (1 << NF_BR_NUMHOOKS))
 285 /* Clear the bit in the hook mask that tells if the rule is on a base chain */
 286 #define CLEAR_BASE_CHAIN_BIT (hookmask &= ~(1 << NF_BR_NUMHOOKS))
 287 /* True if the target is not a standard target */
 288 #define INVALID_TARGET (info->target < -NUM_STANDARD_TARGETS || info->target >= 0)
 289
 290 #endif /* __KERNEL__ */
 291
 292 /* blatently stolen from ip_tables.h
 293  * fn returns 0 to continue iteration */
 294 #define EBT_MATCH_ITERATE(e, fn, args...)                   \
 295 ({                                                          \
 296         unsigned int __i;                                   \
 297         int __ret = 0;                                      \
 298         struct ebt_entry_match *__match;                    \
 299                                                             \
 300         for (__i = sizeof(struct ebt_entry);                \
 301              __i < (e)->watchers_offset;                    \
 302              __i += __match->match_size +                   \
 303              sizeof(struct ebt_entry_match)) {              \
 304                 __match = (void *)(e) + __i;                \
 305                                                             \
 306                 __ret = fn(__match , ## args);              \
 307                 if (__ret != 0)                             \
 308                         break;                              \
 309         }                                                   \
 310         if (__ret == 0) {                                   \
 311                 if (__i != (e)->watchers_offset)            \
 312                         __ret = -EINVAL;                    \
 313         }                                                   \
 314         __ret;                                              \
 315 })
 316
 317 #define EBT_WATCHER_ITERATE(e, fn, args...)                 \
 318 ({                                                          \
 319         unsigned int __i;                                   \
 320         int __ret = 0;                                      \
 321         struct ebt_entry_watcher *__watcher;                \
 322                                                             \
 323         for (__i = e->watchers_offset;                      \
 324              __i < (e)->target_offset;                      \
 325              __i += __watcher->watcher_size +               \
 326              sizeof(struct ebt_entry_watcher)) {            \
 327                 __watcher = (void *)(e) + __i;              \
 328                                                             \
 329                 __ret = fn(__watcher , ## args);            \
 330                 if (__ret != 0)                             \
 331                         break;                              \
 332         }                                                   \
 333         if (__ret == 0) {                                   \
 334                 if (__i != (e)->target_offset)              \
 335                         __ret = -EINVAL;                    \
 336         }                                                   \
 337         __ret;                                              \
 338 })
 339
 340 #define EBT_ENTRY_ITERATE(entries, size, fn, args...)       \
 341 ({                                                          \
 342         unsigned int __i;                                   \
 343         int __ret = 0;                                      \
 344         struct ebt_entry *__entry;                          \
 345                                                             \
 346         for (__i = 0; __i < (size);) {                      \
 347                 __entry = (void *)(entries) + __i;          \
 348                 __ret = fn(__entry , ## args);              \
 349                 if (__ret != 0)                             \
 350                         break;                              \
 351                 if (__entry->bitmask != 0)                  \
 352                         __i += __entry->next_offset;        \
 353                 else                                        \
 354                         __i += sizeof(struct ebt_entries);  \
 355         }                                                   \
 356         if (__ret == 0) {                                   \
 357                 if (__i != (size))                          \
 358                         __ret = -EINVAL;                    \
 359         }                                                   \
 360         __ret;                                              \
 361 })
 362
 363 #endif