include/linux/netfilter_bridge/ebtables.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  ebtables
   4  *
   5  *      Authors:
   6  *      Bart De Schuymer                <bdschuym@pandora.be>
   7  *
   8  *  ebtables.c,v 2.0, April, 2002
   9  *
  10  *  This code is strongly inspired by the iptables code which is
  11  *  Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
  12  */
  13 #ifndef __LINUX_BRIDGE_EFF_H
  14 #define __LINUX_BRIDGE_EFF_H
  15
  16 #include <linux/if.h>
  17 #include <linux/if_ether.h>
  18 #include <uapi/linux/netfilter_bridge/ebtables.h>
  19
  20 struct ebt_match {
  21         struct list_head list;
  22         const char name[EBT_FUNCTION_MAXNAMELEN];
  23         bool (*match)(const struct sk_buff *skb, const struct net_device *in,
  24                 const struct net_device *out, const struct xt_match *match,
  25                 const void *matchinfo, int offset, unsigned int protoff,
  26                 bool *hotdrop);
  27         bool (*checkentry)(const char *table, const void *entry,
  28                 const struct xt_match *match, void *matchinfo,
  29                 unsigned int hook_mask);
  30         void (*destroy)(const struct xt_match *match, void *matchinfo);
  31         unsigned int matchsize;
  32         u_int8_t revision;
  33         u_int8_t family;
  34         struct module *me;
  35 };
  36
  37 struct ebt_watcher {
  38         struct list_head list;
  39         const char name[EBT_FUNCTION_MAXNAMELEN];
  40         unsigned int (*target)(struct sk_buff *skb,
  41                 const struct net_device *in, const struct net_device *out,
  42                 unsigned int hook_num, const struct xt_target *target,
  43                 const void *targinfo);
  44         bool (*checkentry)(const char *table, const void *entry,
  45                 const struct xt_target *target, void *targinfo,
  46                 unsigned int hook_mask);
  47         void (*destroy)(const struct xt_target *target, void *targinfo);
  48         unsigned int targetsize;
  49         u_int8_t revision;
  50         u_int8_t family;
  51         struct module *me;
  52 };
  53
  54 struct ebt_target {
  55         struct list_head list;
  56         const char name[EBT_FUNCTION_MAXNAMELEN];
  57         /* returns one of the standard EBT_* verdicts */
  58         unsigned int (*target)(struct sk_buff *skb,
  59                 const struct net_device *in, const struct net_device *out,
  60                 unsigned int hook_num, const struct xt_target *target,
  61                 const void *targinfo);
  62         bool (*checkentry)(const char *table, const void *entry,
  63                 const struct xt_target *target, void *targinfo,
  64                 unsigned int hook_mask);
  65         void (*destroy)(const struct xt_target *target, void *targinfo);
  66         unsigned int targetsize;
  67         u_int8_t revision;
  68         u_int8_t family;
  69         struct module *me;
  70 };
  71
  72 /* used for jumping from and into user defined chains (udc) */
  73 struct ebt_chainstack {
  74         struct ebt_entries *chaininfo; /* pointer to chain data */
  75         struct ebt_entry *e; /* pointer to entry data */
  76         unsigned int n; /* n'th entry */
  77 };
  78
  79 struct ebt_table_info {
  80         /* total size of the entries */
  81         unsigned int entries_size;
  82         unsigned int nentries;
  83         /* pointers to the start of the chains */
  84         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
  85         /* room to maintain the stack used for jumping from and into udc */
  86         struct ebt_chainstack **chainstack;
  87         char *entries;
  88         struct ebt_counter counters[0] ____cacheline_aligned;
  89 };
  90
  91 struct ebt_table {
  92         struct list_head list;
  93         char name[EBT_TABLE_MAXNAMELEN];
  94         struct ebt_replace_kernel *table;
  95         unsigned int valid_hooks;
  96         rwlock_t lock;
  97         /* e.g. could be the table explicitly only allows certain
  98          * matches, targets, ... 0 == let it in */
  99         int (*check)(const struct ebt_table_info *info,
 100            unsigned int valid_hooks);
 101         /* the data used by the kernel */
 102         struct ebt_table_info *private;
 103         struct module *me;
 104 };
 105
 106 #define EBT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) & \
 107                      ~(__alignof__(struct _xt_align)-1))
 108
 109 extern int ebt_register_table(struct net *net,
 110                               const struct ebt_table *table,
 111                               const struct nf_hook_ops *ops,
 112                               struct ebt_table **res);
 113 extern void ebt_unregister_table(struct net *net, struct ebt_table *table);
 114 void ebt_unregister_table_pre_exit(struct net *net, const char *tablename,
 115                                    const struct nf_hook_ops *ops);
 116 extern unsigned int ebt_do_table(struct sk_buff *skb,
 117                                  const struct nf_hook_state *state,
 118                                  struct ebt_table *table);
 119
 120 /* True if the hook mask denotes that the rule is in a base chain,
 121  * used in the check() functions */
 122 #define BASE_CHAIN (par->hook_mask & (1 << NF_BR_NUMHOOKS))
 123 /* Clear the bit in the hook mask that tells if the rule is on a base chain */
 124 #define CLEAR_BASE_CHAIN_BIT (par->hook_mask &= ~(1 << NF_BR_NUMHOOKS))
 125
 126 static inline bool ebt_invalid_target(int target)
 127 {
 128         return (target < -NUM_STANDARD_TARGETS || target >= 0);
 129 }
 130
 131 #endif