diff options
Diffstat (limited to 'net/ipv4/netfilter/nft_chain_nat_ipv4.c')
| -rw-r--r-- | net/ipv4/netfilter/nft_chain_nat_ipv4.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nft_chain_nat_ipv4.c b/net/ipv4/netfilter/nft_chain_nat_ipv4.c new file mode 100644 index 000000000000..cf2c792cd971 --- /dev/null +++ b/net/ipv4/netfilter/nft_chain_nat_ipv4.c @@ -0,0 +1,205 @@ +/* + * 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 = nfct_nat(ct); + if (nat == NULL) { + /* Conntrack module was loaded late, can't add extension. */ + if (nf_ct_is_confirmed(ct)) + return NF_ACCEPT; + nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC); + 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_pktinfo(&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 struct nf_chain_type nft_chain_nat_ipv4 = { + .family = NFPROTO_IPV4, + .name = "nat", + .type = NFT_CHAIN_T_NAT, + .hook_mask = (1 << NF_INET_PRE_ROUTING) | + (1 << NF_INET_POST_ROUTING) | + (1 << NF_INET_LOCAL_OUT) | + (1 << NF_INET_LOCAL_IN), + .fn = { + [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, + }, + .me = THIS_MODULE, +}; + +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"); |