LXR linux/net/bridge/netfilter/ebtable

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  ebtable_nat
   4 *
   5 *      Authors:
   6 *      Bart De Schuymer <bdschuym@pandora.be>
   7 *
   8 *  April, 2002
   9 *
  10 */
  11
  12#include <linux/netfilter_bridge/ebtables.h>
  13#include <uapi/linux/netfilter_bridge.h>
  14#include <linux/module.h>
  15
  16#define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
  17                         (1 << NF_BR_POST_ROUTING))
  18
  19static struct ebt_entries initial_chains[] = {
  20        {
  21                .name   = "PREROUTING",
  22                .policy = EBT_ACCEPT,
  23        },
  24        {
  25                .name   = "OUTPUT",
  26                .policy = EBT_ACCEPT,
  27        },
  28        {
  29                .name   = "POSTROUTING",
  30                .policy = EBT_ACCEPT,
  31        }
  32};
  33
  34static struct ebt_replace_kernel initial_table = {
  35        .name           = "nat",
  36        .valid_hooks    = NAT_VALID_HOOKS,
  37        .entries_size   = 3 * sizeof(struct ebt_entries),
  38        .hook_entry     = {
  39                [NF_BR_PRE_ROUTING]     = &initial_chains[0],
  40                [NF_BR_LOCAL_OUT]       = &initial_chains[1],
  41                [NF_BR_POST_ROUTING]    = &initial_chains[2],
  42        },
  43        .entries        = (char *)initial_chains,
  44};
  45
  46static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
  47{
  48        if (valid_hooks & ~NAT_VALID_HOOKS)
  49                return -EINVAL;
  50        return 0;
  51}
  52
  53static const struct ebt_table frame_nat = {
  54        .name           = "nat",
  55        .table          = &initial_table,
  56        .valid_hooks    = NAT_VALID_HOOKS,
  57        .check          = check,
  58        .me             = THIS_MODULE,
  59};
  60
  61static unsigned int
  62ebt_nat_in(void *priv, struct sk_buff *skb,
  63           const struct nf_hook_state *state)
  64{
  65        return ebt_do_table(skb, state, state->net->xt.frame_nat);
  66}
  67
  68static unsigned int
  69ebt_nat_out(void *priv, struct sk_buff *skb,
  70            const struct nf_hook_state *state)
  71{
  72        return ebt_do_table(skb, state, state->net->xt.frame_nat);
  73}
  74
  75static const struct nf_hook_ops ebt_ops_nat[] = {
  76        {
  77                .hook           = ebt_nat_out,
  78                .pf             = NFPROTO_BRIDGE,
  79                .hooknum        = NF_BR_LOCAL_OUT,
  80                .priority       = NF_BR_PRI_NAT_DST_OTHER,
  81        },
  82        {
  83                .hook           = ebt_nat_out,
  84                .pf             = NFPROTO_BRIDGE,
  85                .hooknum        = NF_BR_POST_ROUTING,
  86                .priority       = NF_BR_PRI_NAT_SRC,
  87        },
  88        {
  89                .hook           = ebt_nat_in,
  90                .pf             = NFPROTO_BRIDGE,
  91                .hooknum        = NF_BR_PRE_ROUTING,
  92                .priority       = NF_BR_PRI_NAT_DST_BRIDGED,
  93        },
  94};
  95
  96static int __net_init frame_nat_net_init(struct net *net)
  97{
  98        return ebt_register_table(net, &frame_nat, ebt_ops_nat,
  99                                  &net->xt.frame_nat);
 100}
 101
 102static void __net_exit frame_nat_net_exit(struct net *net)
 103{
 104        ebt_unregister_table(net, net->xt.frame_nat, ebt_ops_nat);
 105}
 106
 107static struct pernet_operations frame_nat_net_ops = {
 108        .init = frame_nat_net_init,
 109        .exit = frame_nat_net_exit,
 110};
 111
 112static int __init ebtable_nat_init(void)
 113{
 114        return register_pernet_subsys(&frame_nat_net_ops);
 115}
 116
 117static void __exit ebtable_nat_fini(void)
 118{
 119        unregister_pernet_subsys(&frame_nat_net_ops);
 120}
 121
 122module_init(ebtable_nat_init);
 123module_exit(ebtable_nat_fini);
 124MODULE_LICENSE("GPL");
 125