netfilter: add nf_ipv6_ops hook to fix xt_addrtype with IPv6
[linux-3.10.git] / net / ipv6 / xfrm6_mode_tunnel.c
1 /*
2  * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
3  *
4  * Copyright (C) 2002 USAGI/WIDE Project
5  * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
6  */
7
8 #include <linux/gfp.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/skbuff.h>
13 #include <linux/stringify.h>
14 #include <net/dsfield.h>
15 #include <net/dst.h>
16 #include <net/inet_ecn.h>
17 #include <net/ip6_route.h>
18 #include <net/ipv6.h>
19 #include <net/xfrm.h>
20
21 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
22 {
23         const struct ipv6hdr *outer_iph = ipv6_hdr(skb);
24         struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
25
26         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
27                 IP6_ECN_set_ce(inner_iph);
28 }
29
30 /* Add encapsulation header.
31  *
32  * The top IP header will be constructed per RFC 2401.
33  */
34 static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
35 {
36         struct dst_entry *dst = skb_dst(skb);
37         struct ipv6hdr *top_iph;
38         int dsfield;
39
40         skb_set_network_header(skb, -x->props.header_len);
41         skb->mac_header = skb->network_header +
42                           offsetof(struct ipv6hdr, nexthdr);
43         skb->transport_header = skb->network_header + sizeof(*top_iph);
44         top_iph = ipv6_hdr(skb);
45
46         top_iph->version = 6;
47
48         memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
49                sizeof(top_iph->flow_lbl));
50         top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
51
52         if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
53                 dsfield = 0;
54         else
55                 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
56         dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
57         if (x->props.flags & XFRM_STATE_NOECN)
58                 dsfield &= ~INET_ECN_MASK;
59         ipv6_change_dsfield(top_iph, 0, dsfield);
60         top_iph->hop_limit = ip6_dst_hoplimit(dst->child);
61         top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
62         top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
63         return 0;
64 }
65
66 static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
67 {
68         int err = -EINVAL;
69
70         if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
71                 goto out;
72         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
73                 goto out;
74
75         err = skb_unclone(skb, GFP_ATOMIC);
76         if (err)
77                 goto out;
78
79         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
80                 ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
81                                ipipv6_hdr(skb));
82         if (!(x->props.flags & XFRM_STATE_NOECN))
83                 ipip6_ecn_decapsulate(skb);
84
85         skb_reset_network_header(skb);
86         skb_mac_header_rebuild(skb);
87
88         err = 0;
89
90 out:
91         return err;
92 }
93
94 static struct xfrm_mode xfrm6_tunnel_mode = {
95         .input2 = xfrm6_mode_tunnel_input,
96         .input = xfrm_prepare_input,
97         .output2 = xfrm6_mode_tunnel_output,
98         .output = xfrm6_prepare_output,
99         .owner = THIS_MODULE,
100         .encap = XFRM_MODE_TUNNEL,
101         .flags = XFRM_MODE_FLAG_TUNNEL,
102 };
103
104 static int __init xfrm6_mode_tunnel_init(void)
105 {
106         return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
107 }
108
109 static void __exit xfrm6_mode_tunnel_exit(void)
110 {
111         int err;
112
113         err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
114         BUG_ON(err);
115 }
116
117 module_init(xfrm6_mode_tunnel_init);
118 module_exit(xfrm6_mode_tunnel_exit);
119 MODULE_LICENSE("GPL");
120 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);