![Tomasz Bursztyka](/assets/img/avatar_default.png)
This patch generalizes the NAT expression to support both IPv4 and IPv6 using the existing IPv4/IPv6 NAT infrastructure. This also adds the NAT chain type for IPv6. This patch collapses the following patches that were posted to the netfilter-devel mailing list, from Tomasz: * nf_tables: Change NFTA_NAT_ attributes to better semantic significance * nf_tables: Split IPv4 NAT into NAT expression and IPv4 NAT chain * nf_tables: Add support for IPv6 NAT expression * nf_tables: Add support for IPv6 NAT chain * nf_tables: Fix up build issue on IPv6 NAT support And, from Pablo Neira Ayuso: * fix missing dependencies in nft_chain_nat Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
206 lines
5.3 KiB
C
206 lines
5.3 KiB
C
/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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* Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
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* Copyright (c) 2012 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/nf_nat_core.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_ipv4.h>
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#include <net/netfilter/nf_nat_l3proto.h>
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#include <net/ip.h>
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/*
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* NAT chains
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*/
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static unsigned int nf_nat_fn(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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enum ip_conntrack_info ctinfo;
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struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
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struct nf_conn_nat *nat;
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enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum);
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struct nft_pktinfo pkt;
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unsigned int ret;
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if (ct == NULL || nf_ct_is_untracked(ct))
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return NF_ACCEPT;
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NF_CT_ASSERT(!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)));
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nat = nfct_nat(ct);
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if (nat == NULL) {
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/* Conntrack module was loaded late, can't add extension. */
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if (nf_ct_is_confirmed(ct))
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return NF_ACCEPT;
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nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
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if (nat == NULL)
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return NF_ACCEPT;
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}
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switch (ctinfo) {
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case IP_CT_RELATED:
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case IP_CT_RELATED + IP_CT_IS_REPLY:
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if (ip_hdr(skb)->protocol == IPPROTO_ICMP) {
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if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
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ops->hooknum))
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return NF_DROP;
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else
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return NF_ACCEPT;
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}
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/* Fall through */
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case IP_CT_NEW:
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if (nf_nat_initialized(ct, maniptype))
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break;
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nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
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ret = nft_do_chain_pktinfo(&pkt, ops);
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if (ret != NF_ACCEPT)
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return ret;
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if (!nf_nat_initialized(ct, maniptype)) {
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ret = nf_nat_alloc_null_binding(ct, ops->hooknum);
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if (ret != NF_ACCEPT)
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return ret;
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}
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default:
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break;
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}
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return nf_nat_packet(ct, ctinfo, ops->hooknum, skb);
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}
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static unsigned int nf_nat_prerouting(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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__be32 daddr = ip_hdr(skb)->daddr;
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unsigned int ret;
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ret = nf_nat_fn(ops, skb, in, out, okfn);
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if (ret != NF_DROP && ret != NF_STOLEN &&
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ip_hdr(skb)->daddr != daddr) {
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skb_dst_drop(skb);
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}
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return ret;
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}
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static unsigned int nf_nat_postrouting(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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enum ip_conntrack_info ctinfo __maybe_unused;
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const struct nf_conn *ct __maybe_unused;
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unsigned int ret;
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ret = nf_nat_fn(ops, skb, in, out, okfn);
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#ifdef CONFIG_XFRM
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if (ret != NF_DROP && ret != NF_STOLEN &&
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(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
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enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
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if (ct->tuplehash[dir].tuple.src.u3.ip !=
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ct->tuplehash[!dir].tuple.dst.u3.ip ||
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ct->tuplehash[dir].tuple.src.u.all !=
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ct->tuplehash[!dir].tuple.dst.u.all)
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return nf_xfrm_me_harder(skb, AF_INET) == 0 ?
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ret : NF_DROP;
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}
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#endif
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return ret;
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}
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static unsigned int nf_nat_output(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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enum ip_conntrack_info ctinfo;
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const struct nf_conn *ct;
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unsigned int ret;
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ret = nf_nat_fn(ops, skb, in, out, okfn);
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if (ret != NF_DROP && ret != NF_STOLEN &&
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(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
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enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
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if (ct->tuplehash[dir].tuple.dst.u3.ip !=
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ct->tuplehash[!dir].tuple.src.u3.ip) {
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if (ip_route_me_harder(skb, RTN_UNSPEC))
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ret = NF_DROP;
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}
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#ifdef CONFIG_XFRM
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else if (ct->tuplehash[dir].tuple.dst.u.all !=
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ct->tuplehash[!dir].tuple.src.u.all)
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if (nf_xfrm_me_harder(skb, AF_INET))
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ret = NF_DROP;
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#endif
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}
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return ret;
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}
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static struct nf_chain_type nft_chain_nat_ipv4 = {
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.family = NFPROTO_IPV4,
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.name = "nat",
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.type = NFT_CHAIN_T_NAT,
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.hook_mask = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_LOCAL_IN),
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.fn = {
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[NF_INET_PRE_ROUTING] = nf_nat_prerouting,
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[NF_INET_POST_ROUTING] = nf_nat_postrouting,
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[NF_INET_LOCAL_OUT] = nf_nat_output,
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[NF_INET_LOCAL_IN] = nf_nat_fn,
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},
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.me = THIS_MODULE,
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};
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static int __init nft_chain_nat_init(void)
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{
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int err;
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err = nft_register_chain_type(&nft_chain_nat_ipv4);
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if (err < 0)
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return err;
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return 0;
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}
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static void __exit nft_chain_nat_exit(void)
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{
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nft_unregister_chain_type(&nft_chain_nat_ipv4);
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}
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module_init(nft_chain_nat_init);
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module_exit(nft_chain_nat_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat");
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