| /* |
| * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
| * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org> |
| * Copyright (c) 2012 Intel Corporation |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * Development of this code funded by Astaro AG (http://www.astaro.com/) |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/list.h> |
| #include <linux/skbuff.h> |
| #include <linux/ip.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv4.h> |
| #include <linux/netfilter/nf_tables.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_nat.h> |
| #include <net/netfilter/nf_nat_core.h> |
| #include <net/netfilter/nf_tables.h> |
| #include <net/netfilter/nf_tables_ipv4.h> |
| #include <net/netfilter/nf_nat_l3proto.h> |
| #include <net/ip.h> |
| |
| /* |
| * NAT chains |
| */ |
| |
| static unsigned int nf_nat_fn(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| enum ip_conntrack_info ctinfo; |
| struct nf_conn *ct = nf_ct_get(skb, &ctinfo); |
| struct nf_conn_nat *nat; |
| enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum); |
| struct nft_pktinfo pkt; |
| unsigned int ret; |
| |
| if (ct == NULL || nf_ct_is_untracked(ct)) |
| return NF_ACCEPT; |
| |
| NF_CT_ASSERT(!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET))); |
| |
| nat = nf_ct_nat_ext_add(ct); |
| if (nat == NULL) |
| return NF_ACCEPT; |
| |
| switch (ctinfo) { |
| case IP_CT_RELATED: |
| case IP_CT_RELATED + IP_CT_IS_REPLY: |
| if (ip_hdr(skb)->protocol == IPPROTO_ICMP) { |
| if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo, |
| ops->hooknum)) |
| return NF_DROP; |
| else |
| return NF_ACCEPT; |
| } |
| /* Fall through */ |
| case IP_CT_NEW: |
| if (nf_nat_initialized(ct, maniptype)) |
| break; |
| |
| nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out); |
| |
| ret = nft_do_chain(&pkt, ops); |
| if (ret != NF_ACCEPT) |
| return ret; |
| if (!nf_nat_initialized(ct, maniptype)) { |
| ret = nf_nat_alloc_null_binding(ct, ops->hooknum); |
| if (ret != NF_ACCEPT) |
| return ret; |
| } |
| default: |
| break; |
| } |
| |
| return nf_nat_packet(ct, ctinfo, ops->hooknum, skb); |
| } |
| |
| static unsigned int nf_nat_prerouting(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| __be32 daddr = ip_hdr(skb)->daddr; |
| unsigned int ret; |
| |
| ret = nf_nat_fn(ops, skb, in, out, okfn); |
| if (ret != NF_DROP && ret != NF_STOLEN && |
| ip_hdr(skb)->daddr != daddr) { |
| skb_dst_drop(skb); |
| } |
| return ret; |
| } |
| |
| static unsigned int nf_nat_postrouting(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| enum ip_conntrack_info ctinfo __maybe_unused; |
| const struct nf_conn *ct __maybe_unused; |
| unsigned int ret; |
| |
| ret = nf_nat_fn(ops, skb, in, out, okfn); |
| #ifdef CONFIG_XFRM |
| if (ret != NF_DROP && ret != NF_STOLEN && |
| (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| |
| if (ct->tuplehash[dir].tuple.src.u3.ip != |
| ct->tuplehash[!dir].tuple.dst.u3.ip || |
| ct->tuplehash[dir].tuple.src.u.all != |
| ct->tuplehash[!dir].tuple.dst.u.all) |
| return nf_xfrm_me_harder(skb, AF_INET) == 0 ? |
| ret : NF_DROP; |
| } |
| #endif |
| return ret; |
| } |
| |
| static unsigned int nf_nat_output(const struct nf_hook_ops *ops, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| enum ip_conntrack_info ctinfo; |
| const struct nf_conn *ct; |
| unsigned int ret; |
| |
| ret = nf_nat_fn(ops, skb, in, out, okfn); |
| if (ret != NF_DROP && ret != NF_STOLEN && |
| (ct = nf_ct_get(skb, &ctinfo)) != NULL) { |
| enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); |
| |
| if (ct->tuplehash[dir].tuple.dst.u3.ip != |
| ct->tuplehash[!dir].tuple.src.u3.ip) { |
| if (ip_route_me_harder(skb, RTN_UNSPEC)) |
| ret = NF_DROP; |
| } |
| #ifdef CONFIG_XFRM |
| else if (ct->tuplehash[dir].tuple.dst.u.all != |
| ct->tuplehash[!dir].tuple.src.u.all) |
| if (nf_xfrm_me_harder(skb, AF_INET)) |
| ret = NF_DROP; |
| #endif |
| } |
| return ret; |
| } |
| |
| static const struct nf_chain_type nft_chain_nat_ipv4 = { |
| .name = "nat", |
| .type = NFT_CHAIN_T_NAT, |
| .family = NFPROTO_IPV4, |
| .owner = THIS_MODULE, |
| .hook_mask = (1 << NF_INET_PRE_ROUTING) | |
| (1 << NF_INET_POST_ROUTING) | |
| (1 << NF_INET_LOCAL_OUT) | |
| (1 << NF_INET_LOCAL_IN), |
| .hooks = { |
| [NF_INET_PRE_ROUTING] = nf_nat_prerouting, |
| [NF_INET_POST_ROUTING] = nf_nat_postrouting, |
| [NF_INET_LOCAL_OUT] = nf_nat_output, |
| [NF_INET_LOCAL_IN] = nf_nat_fn, |
| }, |
| }; |
| |
| static int __init nft_chain_nat_init(void) |
| { |
| int err; |
| |
| err = nft_register_chain_type(&nft_chain_nat_ipv4); |
| if (err < 0) |
| return err; |
| |
| return 0; |
| } |
| |
| static void __exit nft_chain_nat_exit(void) |
| { |
| nft_unregister_chain_type(&nft_chain_nat_ipv4); |
| } |
| |
| module_init(nft_chain_nat_init); |
| module_exit(nft_chain_nat_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
| MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat"); |