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 * Development of this code funded by Astaro AG (http://www.astaro.com/)
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/list.h>
15#include <linux/skbuff.h>
16#include <linux/netlink.h>
17#include <linux/netfilter.h>
18#include <linux/netfilter_ipv6.h>
19#include <linux/netfilter/nfnetlink.h>
20#include <linux/netfilter/nf_tables.h>
21#include <net/netfilter/nf_tables.h>
22#include <net/netfilter/nf_tables_ipv6.h>
23#include <net/route.h>
24
25static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
26					struct sk_buff *skb,
27					const struct net_device *in,
28					const struct net_device *out,
29					int (*okfn)(struct sk_buff *))
30{
31	unsigned int ret;
32	struct nft_pktinfo pkt;
33	struct in6_addr saddr, daddr;
34	u_int8_t hop_limit;
35	u32 mark, flowlabel;
36
37	/* malformed packet, drop it */
38	if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
39		return NF_DROP;
40
41	/* save source/dest address, mark, hoplimit, flowlabel, priority */
42	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
43	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
44	mark = skb->mark;
45	hop_limit = ipv6_hdr(skb)->hop_limit;
46
47	/* flowlabel and prio (includes version, which shouldn't change either */
48	flowlabel = *((u32 *)ipv6_hdr(skb));
49
50	ret = nft_do_chain(&pkt, ops);
51	if (ret != NF_DROP && ret != NF_QUEUE &&
52	    (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
53	     memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||
54	     skb->mark != mark ||
55	     ipv6_hdr(skb)->hop_limit != hop_limit ||
56	     flowlabel != *((u_int32_t *)ipv6_hdr(skb))))
57		return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
58
59	return ret;
60}
61
62static const struct nf_chain_type nft_chain_route_ipv6 = {
63	.name		= "route",
64	.type		= NFT_CHAIN_T_ROUTE,
65	.family		= NFPROTO_IPV6,
66        .owner		= THIS_MODULE,
67	.hook_mask	= (1 << NF_INET_LOCAL_OUT),
68	.hooks		= {
69                [NF_INET_LOCAL_OUT]	= nf_route_table_hook,
70        },
71};
72
73static int __init nft_chain_route_init(void)
74{
75	return nft_register_chain_type(&nft_chain_route_ipv6);
76}
77
78static void __exit nft_chain_route_exit(void)
79{
80	nft_unregister_chain_type(&nft_chain_route_ipv6);
81}
82
83module_init(nft_chain_route_init);
84module_exit(nft_chain_route_exit);
85
86MODULE_LICENSE("GPL");
87MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
88MODULE_ALIAS_NFT_CHAIN(AF_INET6, "route");
89