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