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 /* return values for match() functions */
  21 #define EBT_MATCH 0
  22 #define EBT_NOMATCH 1
  23
  24 struct ebt_match {
  25         struct list_head list;
  26         const char name[EBT_FUNCTION_MAXNAMELEN];
  27         bool (*match)(const struct sk_buff *skb, const struct net_device *in,
  28                 const struct net_device *out, const struct xt_match *match,
  29                 const void *matchinfo, int offset, unsigned int protoff,
  30                 bool *hotdrop);
  31         bool (*checkentry)(const char *table, const void *entry,
  32                 const struct xt_match *match, void *matchinfo,
  33                 unsigned int hook_mask);
  34         void (*destroy)(const struct xt_match *match, void *matchinfo);
  35         unsigned int matchsize;
  36         u_int8_t revision;
  37         u_int8_t family;
  38         struct module *me;
  39 };
  40
  41 struct ebt_watcher {
  42         struct list_head list;
  43         const char name[EBT_FUNCTION_MAXNAMELEN];
  44         unsigned int (*target)(struct sk_buff *skb,
  45                 const struct net_device *in, const struct net_device *out,
  46                 unsigned int hook_num, const struct xt_target *target,
  47                 const void *targinfo);
  48         bool (*checkentry)(const char *table, const void *entry,
  49                 const struct xt_target *target, void *targinfo,
  50                 unsigned int hook_mask);
  51         void (*destroy)(const struct xt_target *target, void *targinfo);
  52         unsigned int targetsize;
  53         u_int8_t revision;
  54         u_int8_t family;
  55         struct module *me;
  56 };
  57
  58 struct ebt_target {
  59         struct list_head list;
  60         const char name[EBT_FUNCTION_MAXNAMELEN];
  61         /* returns one of the standard EBT_* verdicts */
  62         unsigned int (*target)(struct sk_buff *skb,
  63                 const struct net_device *in, const struct net_device *out,
  64                 unsigned int hook_num, const struct xt_target *target,
  65                 const void *targinfo);
  66         bool (*checkentry)(const char *table, const void *entry,
  67                 const struct xt_target *target, void *targinfo,
  68                 unsigned int hook_mask);
  69         void (*destroy)(const struct xt_target *target, void *targinfo);
  70         unsigned int targetsize;
  71         u_int8_t revision;
  72         u_int8_t family;
  73         struct module *me;
  74 };
  75
  76 /* used for jumping from and into user defined chains (udc) */
  77 struct ebt_chainstack {
  78         struct ebt_entries *chaininfo; /* pointer to chain data */
  79         struct ebt_entry *e; /* pointer to entry data */
  80         unsigned int n; /* n'th entry */
  81 };
  82
  83 struct ebt_table_info {
  84         /* total size of the entries */
  85         unsigned int entries_size;
  86         unsigned int nentries;
  87         /* pointers to the start of the chains */
  88         struct ebt_entries *hook_entry[NF_BR_NUMHOOKS];
  89         /* room to maintain the stack used for jumping from and into udc */
  90         struct ebt_chainstack **chainstack;
  91         char *entries;
  92         struct ebt_counter counters[0] ____cacheline_aligned;
  93 };
  94
  95 struct ebt_table {
  96         struct list_head list;
  97         char name[EBT_TABLE_MAXNAMELEN];
  98         struct ebt_replace_kernel *table;
  99         unsigned int valid_hooks;
 100         rwlock_t lock;
 101         /* e.g. could be the table explicitly only allows certain
 102          * matches, targets, ... 0 == let it in */
 103         int (*check)(const struct ebt_table_info *info,
 104            unsigned int valid_hooks);
 105         /* the data used by the kernel */
 106         struct ebt_table_info *private;
 107         struct module *me;
 108 };
 109
 110 #define EBT_ALIGN(s) (((s) + (__alignof__(struct _xt_align)-1)) & \
 111                      ~(__alignof__(struct _xt_align)-1))
 112 extern int ebt_register_table(struct net *net,
 113                               const struct ebt_table *table,
 114                               const struct nf_hook_ops *ops,
 115                               struct ebt_table **res);
 116 extern void ebt_unregister_table(struct net *net, struct ebt_table *table,
 117                                  const struct nf_hook_ops *);
 118 extern unsigned int ebt_do_table(struct sk_buff *skb,
 119                                  const struct nf_hook_state *state,
 120                                  struct ebt_table *table);
 121
 122 /* True if the hook mask denotes that the rule is in a base chain,
 123  * used in the check() functions */
 124 #define BASE_CHAIN (par->hook_mask & (1 << NF_BR_NUMHOOKS))
 125 /* Clear the bit in the hook mask that tells if the rule is on a base chain */
 126 #define CLEAR_BASE_CHAIN_BIT (par->hook_mask &= ~(1 << NF_BR_NUMHOOKS))
 127
 128 static inline bool ebt_invalid_target(int target)
 129 {
 130         return (target < -NUM_STANDARD_TARGETS || target >= 0);
 131 }
 132
 133 #endif