1 /*
2 * IPv6 specific functions of netfilter core
3 *
4 * Rusty Russell (C) 2000 -- This code is GPL.
5 * Patrick McHardy (C) 2006-2012
6 */
7 #include <linux/kernel.h>
8 #include <linux/init.h>
9 #include <linux/ipv6.h>
10 #include <linux/netfilter.h>
11 #include <linux/netfilter_ipv6.h>
12 #include <linux/export.h>
13 #include <net/addrconf.h>
14 #include <net/dst.h>
15 #include <net/ipv6.h>
16 #include <net/ip6_route.h>
17 #include <net/xfrm.h>
18 #include <net/netfilter/nf_queue.h>
19
ip6_route_me_harder(struct net * net,struct sk_buff * skb)20 int ip6_route_me_harder(struct net *net, struct sk_buff *skb)
21 {
22 const struct ipv6hdr *iph = ipv6_hdr(skb);
23 struct sock *sk = sk_to_full_sk(skb->sk);
24 unsigned int hh_len;
25 struct dst_entry *dst;
26 struct flowi6 fl6 = {
27 .flowi6_oif = sk ? sk->sk_bound_dev_if : 0,
28 .flowi6_mark = skb->mark,
29 .flowi6_uid = sock_net_uid(net, sk),
30 .daddr = iph->daddr,
31 .saddr = iph->saddr,
32 };
33 int err;
34
35 dst = ip6_route_output(net, sk, &fl6);
36 err = dst->error;
37 if (err) {
38 IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
39 net_dbg_ratelimited("ip6_route_me_harder: No more route\n");
40 dst_release(dst);
41 return err;
42 }
43
44 /* Drop old route. */
45 skb_dst_drop(skb);
46
47 skb_dst_set(skb, dst);
48
49 #ifdef CONFIG_XFRM
50 if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
51 xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
52 skb_dst_set(skb, NULL);
53 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), sk, 0);
54 if (IS_ERR(dst))
55 return PTR_ERR(dst);
56 skb_dst_set(skb, dst);
57 }
58 #endif
59
60 /* Change in oif may mean change in hh_len. */
61 hh_len = skb_dst(skb)->dev->hard_header_len;
62 if (skb_headroom(skb) < hh_len &&
63 pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
64 0, GFP_ATOMIC))
65 return -ENOMEM;
66
67 return 0;
68 }
69 EXPORT_SYMBOL(ip6_route_me_harder);
70
nf_ip6_reroute(struct sk_buff * skb,const struct nf_queue_entry * entry)71 static int nf_ip6_reroute(struct sk_buff *skb,
72 const struct nf_queue_entry *entry)
73 {
74 struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
75
76 if (entry->state.hook == NF_INET_LOCAL_OUT) {
77 const struct ipv6hdr *iph = ipv6_hdr(skb);
78 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
79 !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
80 skb->mark != rt_info->mark)
81 return ip6_route_me_harder(entry->state.net, skb);
82 }
83 return 0;
84 }
85
nf_ip6_route(struct net * net,struct dst_entry ** dst,struct flowi * fl,bool strict)86 static int nf_ip6_route(struct net *net, struct dst_entry **dst,
87 struct flowi *fl, bool strict)
88 {
89 static const struct ipv6_pinfo fake_pinfo;
90 static const struct inet_sock fake_sk = {
91 /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
92 .sk.sk_bound_dev_if = 1,
93 .pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
94 };
95 const void *sk = strict ? &fake_sk : NULL;
96 struct dst_entry *result;
97 int err;
98
99 result = ip6_route_output(net, sk, &fl->u.ip6);
100 err = result->error;
101 if (err)
102 dst_release(result);
103 else
104 *dst = result;
105 return err;
106 }
107
108 static const struct nf_ipv6_ops ipv6ops = {
109 .chk_addr = ipv6_chk_addr,
110 .route_input = ip6_route_input,
111 .fragment = ip6_fragment,
112 .route = nf_ip6_route,
113 .reroute = nf_ip6_reroute,
114 };
115
ipv6_netfilter_init(void)116 int __init ipv6_netfilter_init(void)
117 {
118 RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops);
119 return 0;
120 }
121
122 /* This can be called from inet6_init() on errors, so it cannot
123 * be marked __exit. -DaveM
124 */
ipv6_netfilter_fini(void)125 void ipv6_netfilter_fini(void)
126 {
127 RCU_INIT_POINTER(nf_ipv6_ops, NULL);
128 }
129
