Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 1 | /* |
Patrick McHardy | ef1f7df | 2013-10-10 11:41:20 +0200 | [diff] [blame] | 2 | * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 3 | * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org> |
Tomasz Bursztyka | eb31628 | 2013-10-10 13:39:19 +0200 | [diff] [blame] | 4 | * Copyright (c) 2012 Intel Corporation |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * Development of this code funded by Astaro AG (http://www.astaro.com/) |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/list.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | #include <linux/ip.h> |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 18 | #include <linux/netfilter.h> |
| 19 | #include <linux/netfilter_ipv4.h> |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 20 | #include <linux/netfilter/nf_tables.h> |
| 21 | #include <net/netfilter/nf_conntrack.h> |
| 22 | #include <net/netfilter/nf_nat.h> |
| 23 | #include <net/netfilter/nf_nat_core.h> |
| 24 | #include <net/netfilter/nf_tables.h> |
Pablo Neira Ayuso | 0ca743a | 2013-10-14 00:06:06 +0200 | [diff] [blame] | 25 | #include <net/netfilter/nf_tables_ipv4.h> |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 26 | #include <net/netfilter/nf_nat_l3proto.h> |
| 27 | #include <net/ip.h> |
| 28 | |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 29 | /* |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 30 | * NAT chains |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 31 | */ |
| 32 | |
| 33 | static unsigned int nf_nat_fn(const struct nf_hook_ops *ops, |
| 34 | struct sk_buff *skb, |
| 35 | const struct net_device *in, |
| 36 | const struct net_device *out, |
| 37 | int (*okfn)(struct sk_buff *)) |
| 38 | { |
| 39 | enum ip_conntrack_info ctinfo; |
| 40 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 41 | struct nf_conn_nat *nat; |
| 42 | enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum); |
Pablo Neira Ayuso | 0ca743a | 2013-10-14 00:06:06 +0200 | [diff] [blame] | 43 | struct nft_pktinfo pkt; |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 44 | unsigned int ret; |
| 45 | |
| 46 | if (ct == NULL || nf_ct_is_untracked(ct)) |
| 47 | return NF_ACCEPT; |
| 48 | |
| 49 | NF_CT_ASSERT(!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET))); |
| 50 | |
| 51 | nat = nfct_nat(ct); |
| 52 | if (nat == NULL) { |
| 53 | /* Conntrack module was loaded late, can't add extension. */ |
| 54 | if (nf_ct_is_confirmed(ct)) |
| 55 | return NF_ACCEPT; |
| 56 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); |
| 57 | if (nat == NULL) |
| 58 | return NF_ACCEPT; |
| 59 | } |
| 60 | |
| 61 | switch (ctinfo) { |
| 62 | case IP_CT_RELATED: |
| 63 | case IP_CT_RELATED + IP_CT_IS_REPLY: |
| 64 | if (ip_hdr(skb)->protocol == IPPROTO_ICMP) { |
| 65 | if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo, |
| 66 | ops->hooknum)) |
| 67 | return NF_DROP; |
| 68 | else |
| 69 | return NF_ACCEPT; |
| 70 | } |
| 71 | /* Fall through */ |
| 72 | case IP_CT_NEW: |
| 73 | if (nf_nat_initialized(ct, maniptype)) |
| 74 | break; |
| 75 | |
Pablo Neira Ayuso | 0ca743a | 2013-10-14 00:06:06 +0200 | [diff] [blame] | 76 | nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out); |
| 77 | |
Patrick McHardy | 3876d22 | 2014-01-09 18:42:43 +0000 | [diff] [blame] | 78 | ret = nft_do_chain(&pkt, ops); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 79 | if (ret != NF_ACCEPT) |
| 80 | return ret; |
| 81 | if (!nf_nat_initialized(ct, maniptype)) { |
| 82 | ret = nf_nat_alloc_null_binding(ct, ops->hooknum); |
| 83 | if (ret != NF_ACCEPT) |
| 84 | return ret; |
| 85 | } |
| 86 | default: |
| 87 | break; |
| 88 | } |
| 89 | |
| 90 | return nf_nat_packet(ct, ctinfo, ops->hooknum, skb); |
| 91 | } |
| 92 | |
| 93 | static unsigned int nf_nat_prerouting(const struct nf_hook_ops *ops, |
| 94 | struct sk_buff *skb, |
| 95 | const struct net_device *in, |
| 96 | const struct net_device *out, |
| 97 | int (*okfn)(struct sk_buff *)) |
| 98 | { |
| 99 | __be32 daddr = ip_hdr(skb)->daddr; |
| 100 | unsigned int ret; |
| 101 | |
| 102 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 103 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 104 | ip_hdr(skb)->daddr != daddr) { |
| 105 | skb_dst_drop(skb); |
| 106 | } |
| 107 | return ret; |
| 108 | } |
| 109 | |
| 110 | static unsigned int nf_nat_postrouting(const struct nf_hook_ops *ops, |
| 111 | struct sk_buff *skb, |
| 112 | const struct net_device *in, |
| 113 | const struct net_device *out, |
| 114 | int (*okfn)(struct sk_buff *)) |
| 115 | { |
| 116 | enum ip_conntrack_info ctinfo __maybe_unused; |
| 117 | const struct nf_conn *ct __maybe_unused; |
| 118 | unsigned int ret; |
| 119 | |
| 120 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 121 | #ifdef CONFIG_XFRM |
| 122 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 123 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 124 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 125 | |
| 126 | if (ct->tuplehash[dir].tuple.src.u3.ip != |
| 127 | ct->tuplehash[!dir].tuple.dst.u3.ip || |
| 128 | ct->tuplehash[dir].tuple.src.u.all != |
| 129 | ct->tuplehash[!dir].tuple.dst.u.all) |
| 130 | return nf_xfrm_me_harder(skb, AF_INET) == 0 ? |
| 131 | ret : NF_DROP; |
| 132 | } |
| 133 | #endif |
| 134 | return ret; |
| 135 | } |
| 136 | |
| 137 | static unsigned int nf_nat_output(const struct nf_hook_ops *ops, |
| 138 | struct sk_buff *skb, |
| 139 | const struct net_device *in, |
| 140 | const struct net_device *out, |
| 141 | int (*okfn)(struct sk_buff *)) |
| 142 | { |
| 143 | enum ip_conntrack_info ctinfo; |
| 144 | const struct nf_conn *ct; |
| 145 | unsigned int ret; |
| 146 | |
| 147 | ret = nf_nat_fn(ops, skb, in, out, okfn); |
| 148 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 149 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 150 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 151 | |
| 152 | if (ct->tuplehash[dir].tuple.dst.u3.ip != |
| 153 | ct->tuplehash[!dir].tuple.src.u3.ip) { |
| 154 | if (ip_route_me_harder(skb, RTN_UNSPEC)) |
| 155 | ret = NF_DROP; |
| 156 | } |
| 157 | #ifdef CONFIG_XFRM |
| 158 | else if (ct->tuplehash[dir].tuple.dst.u.all != |
| 159 | ct->tuplehash[!dir].tuple.src.u.all) |
| 160 | if (nf_xfrm_me_harder(skb, AF_INET)) |
| 161 | ret = NF_DROP; |
| 162 | #endif |
| 163 | } |
| 164 | return ret; |
| 165 | } |
| 166 | |
Patrick McHardy | 2a37d75 | 2014-01-09 18:42:37 +0000 | [diff] [blame] | 167 | static const struct nf_chain_type nft_chain_nat_ipv4 = { |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 168 | .name = "nat", |
| 169 | .type = NFT_CHAIN_T_NAT, |
Patrick McHardy | fa2c1de | 2014-01-09 18:42:38 +0000 | [diff] [blame] | 170 | .family = NFPROTO_IPV4, |
| 171 | .owner = THIS_MODULE, |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 172 | .hook_mask = (1 << NF_INET_PRE_ROUTING) | |
| 173 | (1 << NF_INET_POST_ROUTING) | |
| 174 | (1 << NF_INET_LOCAL_OUT) | |
| 175 | (1 << NF_INET_LOCAL_IN), |
Patrick McHardy | fa2c1de | 2014-01-09 18:42:38 +0000 | [diff] [blame] | 176 | .hooks = { |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 177 | [NF_INET_PRE_ROUTING] = nf_nat_prerouting, |
| 178 | [NF_INET_POST_ROUTING] = nf_nat_postrouting, |
| 179 | [NF_INET_LOCAL_OUT] = nf_nat_output, |
| 180 | [NF_INET_LOCAL_IN] = nf_nat_fn, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 181 | }, |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 182 | }; |
| 183 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 184 | static int __init nft_chain_nat_init(void) |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 185 | { |
| 186 | int err; |
| 187 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 188 | err = nft_register_chain_type(&nft_chain_nat_ipv4); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 189 | if (err < 0) |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 190 | return err; |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 191 | |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 192 | return 0; |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 193 | } |
| 194 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 195 | static void __exit nft_chain_nat_exit(void) |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 196 | { |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 197 | nft_unregister_chain_type(&nft_chain_nat_ipv4); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 198 | } |
| 199 | |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 200 | module_init(nft_chain_nat_init); |
| 201 | module_exit(nft_chain_nat_exit); |
Patrick McHardy | 9651851 | 2013-10-14 11:00:02 +0200 | [diff] [blame] | 202 | |
| 203 | MODULE_LICENSE("GPL"); |
| 204 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
Pablo Neira Ayuso | 9370761 | 2013-10-10 23:21:26 +0200 | [diff] [blame] | 205 | MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat"); |