1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> 4 * 5 * Based on Rusty Russell's IPv4 NAT code. Development of IPv6 NAT 6 * funded by Astaro. 7 */ 8 9 #include <linux/module.h> 10 #include <linux/netfilter.h> 11 #include <linux/netfilter_ipv6.h> 12 #include <linux/netfilter_ipv6/ip6_tables.h> 13 #include <linux/ipv6.h> 14 #include <net/ipv6.h> 15 16 #include <net/netfilter/nf_nat.h> 17 18 struct ip6table_nat_pernet { 19 struct nf_hook_ops *nf_nat_ops; 20 }; 21 22 static int __net_init ip6table_nat_table_init(struct net *net); 23 24 static unsigned int ip6table_nat_net_id __read_mostly; 25 26 static const struct xt_table nf_nat_ipv6_table = { 27 .name = "nat", 28 .valid_hooks = (1 << NF_INET_PRE_ROUTING) | 29 (1 << NF_INET_POST_ROUTING) | 30 (1 << NF_INET_LOCAL_OUT) | 31 (1 << NF_INET_LOCAL_IN), 32 .me = THIS_MODULE, 33 .af = NFPROTO_IPV6, 34 .table_init = ip6table_nat_table_init, 35 }; 36 37 static unsigned int ip6table_nat_do_chain(void *priv, 38 struct sk_buff *skb, 39 const struct nf_hook_state *state) 40 { 41 return ip6t_do_table(skb, state, priv); 42 } 43 44 static const struct nf_hook_ops nf_nat_ipv6_ops[] = { 45 { 46 .hook = ip6table_nat_do_chain, 47 .pf = NFPROTO_IPV6, 48 .hooknum = NF_INET_PRE_ROUTING, 49 .priority = NF_IP6_PRI_NAT_DST, 50 }, 51 { 52 .hook = ip6table_nat_do_chain, 53 .pf = NFPROTO_IPV6, 54 .hooknum = NF_INET_POST_ROUTING, 55 .priority = NF_IP6_PRI_NAT_SRC, 56 }, 57 { 58 .hook = ip6table_nat_do_chain, 59 .pf = NFPROTO_IPV6, 60 .hooknum = NF_INET_LOCAL_OUT, 61 .priority = NF_IP6_PRI_NAT_DST, 62 }, 63 { 64 .hook = ip6table_nat_do_chain, 65 .pf = NFPROTO_IPV6, 66 .hooknum = NF_INET_LOCAL_IN, 67 .priority = NF_IP6_PRI_NAT_SRC, 68 }, 69 }; 70 71 static int ip6t_nat_register_lookups(struct net *net) 72 { 73 struct ip6table_nat_pernet *xt_nat_net; 74 struct nf_hook_ops *ops; 75 struct xt_table *table; 76 int i, ret; 77 78 table = xt_find_table(net, NFPROTO_IPV6, "nat"); 79 if (WARN_ON_ONCE(!table)) 80 return -ENOENT; 81 82 xt_nat_net = net_generic(net, ip6table_nat_net_id); 83 ops = kmemdup(nf_nat_ipv6_ops, sizeof(nf_nat_ipv6_ops), GFP_KERNEL); 84 if (!ops) 85 return -ENOMEM; 86 87 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) { 88 ops[i].priv = table; 89 ret = nf_nat_ipv6_register_fn(net, &ops[i]); 90 if (ret) { 91 while (i) 92 nf_nat_ipv6_unregister_fn(net, &ops[--i]); 93 94 kfree(ops); 95 return ret; 96 } 97 } 98 99 xt_nat_net->nf_nat_ops = ops; 100 return 0; 101 } 102 103 static void ip6t_nat_unregister_lookups(struct net *net) 104 { 105 struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id); 106 struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops; 107 int i; 108 109 if (!ops) 110 return; 111 112 for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) 113 nf_nat_ipv6_unregister_fn(net, &ops[i]); 114 115 kfree(ops); 116 } 117 118 static int __net_init ip6table_nat_table_init(struct net *net) 119 { 120 struct ip6t_replace *repl; 121 int ret; 122 123 repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table); 124 if (repl == NULL) 125 return -ENOMEM; 126 ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl, 127 NULL); 128 if (ret < 0) { 129 kfree(repl); 130 return ret; 131 } 132 133 ret = ip6t_nat_register_lookups(net); 134 if (ret < 0) 135 ip6t_unregister_table_exit(net, "nat"); 136 137 kfree(repl); 138 return ret; 139 } 140 141 static void __net_exit ip6table_nat_net_pre_exit(struct net *net) 142 { 143 ip6t_nat_unregister_lookups(net); 144 } 145 146 static void __net_exit ip6table_nat_net_exit(struct net *net) 147 { 148 ip6t_unregister_table_exit(net, "nat"); 149 } 150 151 static struct pernet_operations ip6table_nat_net_ops = { 152 .pre_exit = ip6table_nat_net_pre_exit, 153 .exit = ip6table_nat_net_exit, 154 .id = &ip6table_nat_net_id, 155 .size = sizeof(struct ip6table_nat_pernet), 156 }; 157 158 static int __init ip6table_nat_init(void) 159 { 160 int ret = register_pernet_subsys(&ip6table_nat_net_ops); 161 162 if (ret) 163 return ret; 164 165 ret = ip6table_nat_table_init(&init_net); 166 if (ret) 167 unregister_pernet_subsys(&ip6table_nat_net_ops); 168 return ret; 169 } 170 171 static void __exit ip6table_nat_exit(void) 172 { 173 unregister_pernet_subsys(&ip6table_nat_net_ops); 174 } 175 176 module_init(ip6table_nat_init); 177 module_exit(ip6table_nat_exit); 178 179 MODULE_LICENSE("GPL"); 180