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 __user *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 __user *counters;
  54         char __user *entries;
  55 };
  56
  57 struct ebt_replace_kernel
  58 {
  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 alot, 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 {
 122         union {
 123                 char name[EBT_FUNCTION_MAXNAMELEN];
 124                 struct ebt_match *match;
 125         } u;
 126         /* size of data */
 127         unsigned int match_size;
 128         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 129 };
 130
 131 struct ebt_entry_watcher
 132 {
 133         union {
 134                 char name[EBT_FUNCTION_MAXNAMELEN];
 135                 struct ebt_watcher *watcher;
 136         } u;
 137         /* size of data */
 138         unsigned int watcher_size;
 139         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 140 };
 141
 142 struct ebt_entry_target
 143 {
 144         union {
 145                 char name[EBT_FUNCTION_MAXNAMELEN];
 146                 struct ebt_target *target;
 147         } u;
 148         /* size of data */
 149         unsigned int target_size;
 150         unsigned char data[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 151 };
 152
 153 #define EBT_STANDARD_TARGET "standard"
 154 struct ebt_standard_target
 155 {
 156         struct ebt_entry_target target;
 157         int verdict;
 158 };
 159
 160 /* one entry */
 161 struct ebt_entry {
 162         /* this needs to be the first field */
 163         unsigned int bitmask;
 164         unsigned int invflags;
 165         __be16 ethproto;
 166         /* the physical in-dev */
 167         char in[IFNAMSIZ];
 168         /* the logical in-dev */
 169         char logical_in[IFNAMSIZ];
 170         /* the physical out-dev */
 171         char out[IFNAMSIZ];
 172         /* the logical out-dev */
 173         char logical_out[IFNAMSIZ];
 174         unsigned char sourcemac[ETH_ALEN];
 175         unsigned char sourcemsk[ETH_ALEN];
 176         unsigned char destmac[ETH_ALEN];
 177         unsigned char destmsk[ETH_ALEN];
 178         /* sizeof ebt_entry + matches */
 179         unsigned int watchers_offset;
 180         /* sizeof ebt_entry + matches + watchers */
 181         unsigned int target_offset;
 182         /* sizeof ebt_entry + matches + watchers + target */
 183         unsigned int next_offset;
 184         unsigned char elems[0] __attribute__ ((aligned (__alignof__(struct ebt_replace))));
 185 };
 186
 187 /* {g,s}etsockopt numbers */
 188 #define EBT_BASE_CTL            128
 189
 190 #define EBT_SO_SET_ENTRIES      (EBT_BASE_CTL)
 191 #define EBT_SO_SET_COUNTERS     (EBT_SO_SET_ENTRIES+1)
 192 #define EBT_SO_SET_MAX          (EBT_SO_SET_COUNTERS+1)
 193
 194 #define EBT_SO_GET_INFO         (EBT_BASE_CTL)
 195 #define EBT_SO_GET_ENTRIES      (EBT_SO_GET_INFO+1)
 196 #define EBT_SO_GET_INIT_INFO    (EBT_SO_GET_ENTRIES+1)
 197 #define EBT_SO_GET_INIT_ENTRIES (EBT_SO_GET_INIT_INFO+1)
 198 #define EBT_SO_GET_MAX          (EBT_SO_GET_INIT_ENTRIES+1)
 199
 200 #ifdef __KERNEL__
 201
 202 /* return values for match() functions */
 203 #define EBT_MATCH 0
 204 #define EBT_NOMATCH 1
 205
 206 struct ebt_match
 207 {
 208         struct list_head list;
 209         const char name[EBT_FUNCTION_MAXNAMELEN];
 210         /* 0 == it matches */
 211         int (*match)(const struct sk_buff *skb, const struct net_device *in,
 212            const struct net_device *out, const void *matchdata,
 213            unsigned int datalen);
 214         /* 0 == let it in */
 215         int (*check)(const char *tablename, unsigned int hookmask,
 216            const struct ebt_entry *e, void *matchdata, unsigned int datalen);
 217         void (*destroy)(void *matchdata, unsigned int datalen);
 218         struct module *me;
 219 };
 220
 221 struct ebt_watcher
 222 {
 223         struct list_head list;
 224         const char name[EBT_FUNCTION_MAXNAMELEN];
 225         void (*watcher)(const struct sk_buff *skb, unsigned int hooknr,
 226            const struct net_device *in, const struct net_device *out,
 227            const void *watcherdata, unsigned int datalen);
 228         /* 0 == let it in */
 229         int (*check)(const char *tablename, unsigned int hookmask,
 230            const struct ebt_entry *e, void *watcherdata, unsigned int datalen);
 231         void (*destroy)(void *watcherdata, unsigned int datalen);
 232         struct module *me;
 233 };
 234
 235 struct ebt_target
 236 {
 237         struct list_head list;
 238         const char name[EBT_FUNCTION_MAXNAMELEN];
 239         /* returns one of the standard verdicts */
 240         int (*target)(struct sk_buff *skb, unsigned int hooknr,
 241            const struct net_device *in, const struct net_device *out,
 242            const void *targetdata, unsigned int datalen);
 243         /* 0 == let it in */
 244         int (*check)(const char *tablename, unsigned int hookmask,
 245            const struct ebt_entry *e, void *targetdata, unsigned int datalen);
 246         void (*destroy)(void *targetdata, unsigned int datalen);
 247         struct module *me;
 248 };
 249
 250 /* used for jumping from and into user defined chains (udc) */
 251 struct ebt_chainstack
 252 {
 253         struct ebt_entries *chaininfo; /* pointer to chain data */
 254         struct ebt_entry *e; /* pointer to entry data */
 255         unsigned int n; /* n'th entry */
 256 };
 257
 258 struct ebt_table_info
 259 {
 260         /* total size of the entries */
 261         unsigned int entries_size;
 262         unsigned int nentries;
 263         /* pointers to the start of the chains */
 264         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
 265         /* room to maintain the stack used for jumping from and into udc */
 266         struct ebt_chainstack **chainstack;
 267         char *entries;
 268         struct ebt_counter counters[0] ____cacheline_aligned;
 269 };
 270
 271 struct ebt_table
 272 {
 273         struct list_head list;
 274         char name[EBT_TABLE_MAXNAMELEN];
 275         struct ebt_replace_kernel *table;
 276         unsigned int valid_hooks;
 277         rwlock_t lock;
 278         /* e.g. could be the table explicitly only allows certain
 279          * matches, targets, ... 0 == let it in */
 280         int (*check)(const struct ebt_table_info *info,
 281            unsigned int valid_hooks);
 282         /* the data used by the kernel */
 283         struct ebt_table_info *private;
 284         struct module *me;
 285 };
 286
 287 #define EBT_ALIGN(s) (((s) + (__alignof__(struct ebt_replace)-1)) & \
 288                      ~(__alignof__(struct ebt_replace)-1))
 289 extern int ebt_register_table(struct ebt_table *table);
 290 extern void ebt_unregister_table(struct ebt_table *table);
 291 extern int ebt_register_match(struct ebt_match *match);
 292 extern void ebt_unregister_match(struct ebt_match *match);
 293 extern int ebt_register_watcher(struct ebt_watcher *watcher);
 294 extern void ebt_unregister_watcher(struct ebt_watcher *watcher);
 295 extern int ebt_register_target(struct ebt_target *target);
 296 extern void ebt_unregister_target(struct ebt_target *target);
 297 extern unsigned int ebt_do_table(unsigned int hook, struct sk_buff *skb,
 298    const struct net_device *in, const struct net_device *out,
 299    struct ebt_table *table);
 300
 301 /* Used in the kernel match() functions */
 302 #define FWINV(bool,invflg) ((bool) ^ !!(info->invflags & invflg))
 303 /* True if the hook mask denotes that the rule is in a base chain,
 304  * used in the check() functions */
 305 #define BASE_CHAIN (hookmask & (1 << NF_BR_NUMHOOKS))
 306 /* Clear the bit in the hook mask that tells if the rule is on a base chain */
 307 #define CLEAR_BASE_CHAIN_BIT (hookmask &= ~(1 << NF_BR_NUMHOOKS))
 308 /* True if the target is not a standard target */
 309 #define INVALID_TARGET (info->target < -NUM_STANDARD_TARGETS || info->target >= 0)
 310
 311 #endif /* __KERNEL__ */
 312
 313 /* blatently stolen from ip_tables.h
 314  * fn returns 0 to continue iteration */
 315 #define EBT_MATCH_ITERATE(e, fn, args...)                   \
 316 ({                                                          \
 317         unsigned int __i;                                   \
 318         int __ret = 0;                                      \
 319         struct ebt_entry_match *__match;                    \
 320                                                             \
 321         for (__i = sizeof(struct ebt_entry);                \
 322              __i < (e)->watchers_offset;                    \
 323              __i += __match->match_size +                   \
 324              sizeof(struct ebt_entry_match)) {              \
 325                 __match = (void *)(e) + __i;                \
 326                                                             \
 327                 __ret = fn(__match , ## args);              \
 328                 if (__ret != 0)                             \
 329                         break;                              \
 330         }                                                   \
 331         if (__ret == 0) {                                   \
 332                 if (__i != (e)->watchers_offset)            \
 333                         __ret = -EINVAL;                    \
 334         }                                                   \
 335         __ret;                                              \
 336 })
 337
 338 #define EBT_WATCHER_ITERATE(e, fn, args...)                 \
 339 ({                                                          \
 340         unsigned int __i;                                   \
 341         int __ret = 0;                                      \
 342         struct ebt_entry_watcher *__watcher;                \
 343                                                             \
 344         for (__i = e->watchers_offset;                      \
 345              __i < (e)->target_offset;                      \
 346              __i += __watcher->watcher_size +               \
 347              sizeof(struct ebt_entry_watcher)) {            \
 348                 __watcher = (void *)(e) + __i;              \
 349                                                             \
 350                 __ret = fn(__watcher , ## args);            \
 351                 if (__ret != 0)                             \
 352                         break;                              \
 353         }                                                   \
 354         if (__ret == 0) {                                   \
 355                 if (__i != (e)->target_offset)              \
 356                         __ret = -EINVAL;                    \
 357         }                                                   \
 358         __ret;                                              \
 359 })
 360
 361 #define EBT_ENTRY_ITERATE(entries, size, fn, args...)       \
 362 ({                                                          \
 363         unsigned int __i;                                   \
 364         int __ret = 0;                                      \
 365         struct ebt_entry *__entry;                          \
 366                                                             \
 367         for (__i = 0; __i < (size);) {                      \
 368                 __entry = (void *)(entries) + __i;          \
 369                 __ret = fn(__entry , ## args);              \
 370                 if (__ret != 0)                             \
 371                         break;                              \
 372                 if (__entry->bitmask != 0)                  \
 373                         __i += __entry->next_offset;        \
 374                 else                                        \
 375                         __i += sizeof(struct ebt_entries);  \
 376         }                                                   \
 377         if (__ret == 0) {                                   \
 378                 if (__i != (size))                          \
 379                         __ret = -EINVAL;                    \
 380         }                                                   \
 381         __ret;                                              \
 382 })
 383
 384 #endif