1/*
2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
3 * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/list.h>
13#include <linux/skbuff.h>
14#include <linux/netlink.h>
15#include <linux/netfilter.h>
16#include <linux/netfilter_ipv4.h>
17#include <linux/netfilter/nfnetlink.h>
18#include <linux/netfilter/nf_tables.h>
19#include <net/netfilter/nf_tables.h>
20#include <net/netfilter/nf_tables_ipv4.h>
21#include <net/route.h>
22#include <net/ip.h>
23
24static unsigned int nf_route_table_hook(void *priv,
25 struct sk_buff *skb,
26 const struct nf_hook_state *state)
27{
28 unsigned int ret;
29 struct nft_pktinfo pkt;
30 u32 mark;
31 __be32 saddr, daddr;
32 u_int8_t tos;
33 const struct iphdr *iph;
34 int err;
35
36 nft_set_pktinfo(&pkt, skb, state);
37 nft_set_pktinfo_ipv4(&pkt, skb);
38
39 mark = skb->mark;
40 iph = ip_hdr(skb);
41 saddr = iph->saddr;
42 daddr = iph->daddr;
43 tos = iph->tos;
44
45 ret = nft_do_chain(&pkt, priv);
46 if (ret != NF_DROP && ret != NF_STOLEN) {
47 iph = ip_hdr(skb);
48
49 if (iph->saddr != saddr ||
50 iph->daddr != daddr ||
51 skb->mark != mark ||
52 iph->tos != tos) {
53 err = ip_route_me_harder(state->net, skb, RTN_UNSPEC);
54 if (err < 0)
55 ret = NF_DROP_ERR(err);
56 }
57 }
58 return ret;
59}
60
61static const struct nft_chain_type nft_chain_route_ipv4 = {
62 .name = "route",
63 .type = NFT_CHAIN_T_ROUTE,
64 .family = NFPROTO_IPV4,
65 .owner = THIS_MODULE,
66 .hook_mask = (1 << NF_INET_LOCAL_OUT),
67 .hooks = {
68 [NF_INET_LOCAL_OUT] = nf_route_table_hook,
69 },
70};
71
72static int __init nft_chain_route_init(void)
73{
74 nft_register_chain_type(&nft_chain_route_ipv4);
75
76 return 0;
77}
78
79static void __exit nft_chain_route_exit(void)
80{
81 nft_unregister_chain_type(&nft_chain_route_ipv4);
82}
83
84module_init(nft_chain_route_init);
85module_exit(nft_chain_route_exit);
86
87MODULE_LICENSE("GPL");
88MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
89MODULE_ALIAS_NFT_CHAIN(AF_INET, "route");
90