Tomasz Bursztyka | eb31628 | 2013-10-10 13:39:19 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> |
| 3 | * Copyright (c) 2012 Intel Corporation |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms and conditions of the GNU General Public License, |
| 7 | * version 2, as published by the Free Software Foundation. |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/list.h> |
| 14 | #include <linux/skbuff.h> |
| 15 | #include <linux/ip.h> |
| 16 | #include <linux/netfilter.h> |
| 17 | #include <linux/netfilter_ipv6.h> |
| 18 | #include <linux/netfilter/nf_tables.h> |
| 19 | #include <net/netfilter/nf_conntrack.h> |
| 20 | #include <net/netfilter/nf_nat.h> |
| 21 | #include <net/netfilter/nf_nat_core.h> |
| 22 | #include <net/netfilter/nf_tables.h> |
| 23 | #include <net/netfilter/nf_tables_ipv6.h> |
| 24 | #include <net/netfilter/nf_nat_l3proto.h> |
| 25 | #include <net/ipv6.h> |
| 26 | |
| 27 | /* |
| 28 | * IPv6 NAT chains |
| 29 | */ |
| 30 | |
| 31 | static unsigned int nf_nat_ipv6_fn(const struct nf_hook_ops *ops, |
| 32 | struct sk_buff *skb, |
| 33 | const struct net_device *in, |
| 34 | const struct net_device *out, |
| 35 | int (*okfn)(struct sk_buff *)) |
| 36 | { |
| 37 | enum ip_conntrack_info ctinfo; |
| 38 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| 39 | struct nf_conn_nat *nat; |
| 40 | enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum); |
| 41 | __be16 frag_off; |
| 42 | int hdrlen; |
| 43 | u8 nexthdr; |
| 44 | struct nft_pktinfo pkt; |
| 45 | unsigned int ret; |
| 46 | |
| 47 | if (ct == NULL || nf_ct_is_untracked(ct)) |
| 48 | return NF_ACCEPT; |
| 49 | |
| 50 | nat = nfct_nat(ct); |
| 51 | if (nat == NULL) { |
| 52 | /* Conntrack module was loaded late, can't add extension. */ |
| 53 | if (nf_ct_is_confirmed(ct)) |
| 54 | return NF_ACCEPT; |
| 55 | nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); |
| 56 | if (nat == NULL) |
| 57 | return NF_ACCEPT; |
| 58 | } |
| 59 | |
| 60 | switch (ctinfo) { |
| 61 | case IP_CT_RELATED: |
| 62 | case IP_CT_RELATED + IP_CT_IS_REPLY: |
| 63 | nexthdr = ipv6_hdr(skb)->nexthdr; |
| 64 | hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), |
| 65 | &nexthdr, &frag_off); |
| 66 | |
| 67 | if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) { |
| 68 | if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo, |
| 69 | ops->hooknum, |
| 70 | hdrlen)) |
| 71 | return NF_DROP; |
| 72 | else |
| 73 | return NF_ACCEPT; |
| 74 | } |
| 75 | /* Fall through */ |
| 76 | case IP_CT_NEW: |
| 77 | if (nf_nat_initialized(ct, maniptype)) |
| 78 | break; |
| 79 | |
| 80 | nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out); |
| 81 | |
| 82 | ret = nft_do_chain_pktinfo(&pkt, ops); |
| 83 | if (ret != NF_ACCEPT) |
| 84 | return ret; |
| 85 | if (!nf_nat_initialized(ct, maniptype)) { |
| 86 | ret = nf_nat_alloc_null_binding(ct, ops->hooknum); |
| 87 | if (ret != NF_ACCEPT) |
| 88 | return ret; |
| 89 | } |
| 90 | default: |
| 91 | break; |
| 92 | } |
| 93 | |
| 94 | return nf_nat_packet(ct, ctinfo, ops->hooknum, skb); |
| 95 | } |
| 96 | |
| 97 | static unsigned int nf_nat_ipv6_prerouting(const struct nf_hook_ops *ops, |
| 98 | struct sk_buff *skb, |
| 99 | const struct net_device *in, |
| 100 | const struct net_device *out, |
| 101 | int (*okfn)(struct sk_buff *)) |
| 102 | { |
| 103 | struct in6_addr daddr = ipv6_hdr(skb)->daddr; |
| 104 | unsigned int ret; |
| 105 | |
| 106 | ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn); |
| 107 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 108 | ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr)) |
| 109 | skb_dst_drop(skb); |
| 110 | |
| 111 | return ret; |
| 112 | } |
| 113 | |
| 114 | static unsigned int nf_nat_ipv6_postrouting(const struct nf_hook_ops *ops, |
| 115 | struct sk_buff *skb, |
| 116 | const struct net_device *in, |
| 117 | const struct net_device *out, |
| 118 | int (*okfn)(struct sk_buff *)) |
| 119 | { |
| 120 | enum ip_conntrack_info ctinfo __maybe_unused; |
| 121 | const struct nf_conn *ct __maybe_unused; |
| 122 | unsigned int ret; |
| 123 | |
| 124 | ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn); |
| 125 | #ifdef CONFIG_XFRM |
| 126 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 127 | !(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && |
| 128 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 129 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 130 | |
| 131 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3, |
| 132 | &ct->tuplehash[!dir].tuple.dst.u3) || |
| 133 | (ct->tuplehash[dir].tuple.src.u.all != |
| 134 | ct->tuplehash[!dir].tuple.dst.u.all)) |
| 135 | if (nf_xfrm_me_harder(skb, AF_INET6) < 0) |
| 136 | ret = NF_DROP; |
| 137 | } |
| 138 | #endif |
| 139 | return ret; |
| 140 | } |
| 141 | |
| 142 | static unsigned int nf_nat_ipv6_output(const struct nf_hook_ops *ops, |
| 143 | struct sk_buff *skb, |
| 144 | const struct net_device *in, |
| 145 | const struct net_device *out, |
| 146 | int (*okfn)(struct sk_buff *)) |
| 147 | { |
| 148 | enum ip_conntrack_info ctinfo; |
| 149 | const struct nf_conn *ct; |
| 150 | unsigned int ret; |
| 151 | |
| 152 | ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn); |
| 153 | if (ret != NF_DROP && ret != NF_STOLEN && |
| 154 | (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| 155 | enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| 156 | |
| 157 | if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3, |
| 158 | &ct->tuplehash[!dir].tuple.src.u3)) { |
| 159 | if (ip6_route_me_harder(skb)) |
| 160 | ret = NF_DROP; |
| 161 | } |
| 162 | #ifdef CONFIG_XFRM |
| 163 | else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) && |
| 164 | ct->tuplehash[dir].tuple.dst.u.all != |
| 165 | ct->tuplehash[!dir].tuple.src.u.all) |
| 166 | if (nf_xfrm_me_harder(skb, AF_INET6)) |
| 167 | ret = NF_DROP; |
| 168 | #endif |
| 169 | } |
| 170 | return ret; |
| 171 | } |
| 172 | |
| 173 | static struct nf_chain_type nft_chain_nat_ipv6 = { |
| 174 | .family = NFPROTO_IPV6, |
| 175 | .name = "nat", |
| 176 | .type = NFT_CHAIN_T_NAT, |
| 177 | .hook_mask = (1 << NF_INET_PRE_ROUTING) | |
| 178 | (1 << NF_INET_POST_ROUTING) | |
| 179 | (1 << NF_INET_LOCAL_OUT) | |
| 180 | (1 << NF_INET_LOCAL_IN), |
| 181 | .fn = { |
| 182 | [NF_INET_PRE_ROUTING] = nf_nat_ipv6_prerouting, |
| 183 | [NF_INET_POST_ROUTING] = nf_nat_ipv6_postrouting, |
| 184 | [NF_INET_LOCAL_OUT] = nf_nat_ipv6_output, |
| 185 | [NF_INET_LOCAL_IN] = nf_nat_ipv6_fn, |
| 186 | }, |
| 187 | .me = THIS_MODULE, |
| 188 | }; |
| 189 | |
| 190 | static int __init nft_chain_nat_ipv6_init(void) |
| 191 | { |
| 192 | int err; |
| 193 | |
| 194 | err = nft_register_chain_type(&nft_chain_nat_ipv6); |
| 195 | if (err < 0) |
| 196 | return err; |
| 197 | |
| 198 | return 0; |
| 199 | } |
| 200 | |
| 201 | static void __exit nft_chain_nat_ipv6_exit(void) |
| 202 | { |
| 203 | nft_unregister_chain_type(&nft_chain_nat_ipv6); |
| 204 | } |
| 205 | |
| 206 | module_init(nft_chain_nat_ipv6_init); |
| 207 | module_exit(nft_chain_nat_ipv6_exit); |
| 208 | |
| 209 | MODULE_LICENSE("GPL"); |
| 210 | MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>"); |
| 211 | MODULE_ALIAS_NFT_CHAIN(AF_INET6, "nat"); |