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 17static 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 33static 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 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 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 62static unsigned int 63ebt_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 69static unsigned int 70ebt_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 76static 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 100static int __net_init frame_nat_net_init(struct net *net) 101{ 102 net->xt.frame_nat = ebt_register_table(net, &frame_nat); 103 if (IS_ERR(net->xt.frame_nat)) 104 return PTR_ERR(net->xt.frame_nat); 105 return 0; 106} 107 108static void __net_exit frame_nat_net_exit(struct net *net) 109{ 110 ebt_unregister_table(net, net->xt.frame_nat); 111} 112 113static struct pernet_operations frame_nat_net_ops = { 114 .init = frame_nat_net_init, 115 .exit = frame_nat_net_exit, 116}; 117 118static int __init ebtable_nat_init(void) 119{ 120 int ret; 121 122 ret = register_pernet_subsys(&frame_nat_net_ops); 123 if (ret < 0) 124 return ret; 125 ret = nf_register_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat)); 126 if (ret < 0) 127 unregister_pernet_subsys(&frame_nat_net_ops); 128 return ret; 129} 130 131static void __exit ebtable_nat_fini(void) 132{ 133 nf_unregister_hooks(ebt_ops_nat, ARRAY_SIZE(ebt_ops_nat)); 134 unregister_pernet_subsys(&frame_nat_net_ops); 135} 136 137module_init(ebtable_nat_init); 138module_exit(ebtable_nat_fini); 139MODULE_LICENSE("GPL"); 140