1 /* 2 * ebtable_nat 3 * 4 * Authors: 5 * Bart De Schuymer <bdschuym@pandora.be> 6 * 7 * April, 2002 8 * 9 */ 10 11 #include <linux/netfilter_bridge/ebtables.h> 12 #include <linux/module.h> 13 14 #define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \ 15 (1 << NF_BR_POST_ROUTING)) 16 17 static struct ebt_entries initial_chains[] = 18 { 19 { 20 .name = "PREROUTING", 21 .policy = EBT_ACCEPT, 22 }, 23 { 24 .name = "OUTPUT", 25 .policy = EBT_ACCEPT, 26 }, 27 { 28 .name = "POSTROUTING", 29 .policy = EBT_ACCEPT, 30 } 31 }; 32 33 static struct ebt_replace_kernel initial_table = 34 { 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 46 static 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 53 static struct ebt_table frame_nat = 54 { 55 .name = "nat", 56 .table = &initial_table, 57 .valid_hooks = NAT_VALID_HOOKS, 58 .check = check, 59 .me = THIS_MODULE, 60 }; 61 62 static unsigned int 63 ebt_nat_in(unsigned int hook, struct sk_buff *skb, const struct net_device *in 64 , const struct net_device *out, int (*okfn)(struct sk_buff *)) 65 { 66 return ebt_do_table(hook, skb, in, out, dev_net(in)->xt.frame_nat); 67 } 68 69 static unsigned int 70 ebt_nat_out(unsigned int hook, struct sk_buff *skb, const struct net_device *in 71 , const struct net_device *out, int (*okfn)(struct sk_buff *)) 72 { 73 return ebt_do_table(hook, skb, in, out, dev_net(out)->xt.frame_nat); 74 } 75 76 static struct nf_hook_ops ebt_ops_nat[] __read_mostly = { 77 { 78 .hook = ebt_nat_out, 79 .owner = THIS_MODULE, 80 .pf = NFPROTO_BRIDGE, 81 .hooknum = NF_BR_LOCAL_OUT, 82 .priority = NF_BR_PRI_NAT_DST_OTHER, 83 }, 84 { 85 .hook = ebt_nat_out, 86 .owner = THIS_MODULE, 87 .pf = NFPROTO_BRIDGE, 88 .hooknum = NF_BR_POST_ROUTING, 89 .priority = NF_BR_PRI_NAT_SRC, 90 }, 91 { 92 .hook = ebt_nat_in, 93 .owner = THIS_MODULE, 94 .pf = NFPROTO_BRIDGE, 95 .hooknum = NF_BR_PRE_ROUTING, 96 .priority = NF_BR_PRI_NAT_DST_BRIDGED, 97 }, 98 }; 99 100 static int __net_init frame_nat_net_init(struct net *net) 101 { 102 net->xt.frame_nat = ebt_register_table(net, &frame_nat); 103 return PTR_RET(net->xt.frame_nat); 104 } 105 106 static void __net_exit frame_nat_net_exit(struct net *net) 107 { 108 ebt_unregister_table(net, net->xt.frame_nat); 109 } 110 111 static struct pernet_operations frame_nat_net_ops = { 112 .init = frame_nat_net_init, 113 .exit = frame_nat_net_exit, 114 }; 115 116 static int __init ebtable_nat_init(void) 117 { 118 int ret; 119 120 ret = register_pernet_subsys(&frame_nat_net_ops); 121 if (ret < 0) 122 return ret; 123 ret = nf_register_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat)); 124 if (ret < 0) 125 unregister_pernet_subsys(&frame_nat_net_ops); 126 return ret; 127 } 128 129 static void __exit ebtable_nat_fini(void) 130 { 131 nf_unregister_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat)); 132 unregister_pernet_subsys(&frame_nat_net_ops); 133 } 134 135 module_init(ebtable_nat_init); 136 module_exit(ebtable_nat_fini); 137 MODULE_LICENSE("GPL"); 138