blob: 5e7d8a7d6414cc85a01fd463485c016af1d5a219 [file] [log] [blame]
Herbert Xub59f45d2006-05-27 23:05:54 -07001/*
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/init.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/stringify.h>
13#include <net/dsfield.h>
14#include <net/dst.h>
15#include <net/inet_ecn.h>
16#include <net/ipv6.h>
17#include <net/xfrm.h>
18
19static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
20{
21 struct ipv6hdr *outer_iph = skb->nh.ipv6h;
22 struct ipv6hdr *inner_iph = skb->h.ipv6h;
23
24 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
25 IP6_ECN_set_ce(inner_iph);
26}
27
28/* Add encapsulation header.
29 *
30 * The top IP header will be constructed per RFC 2401. The following fields
31 * in it shall be filled in by x->type->output:
32 * payload_len
33 *
34 * On exit, skb->h will be set to the start of the encapsulation header to be
35 * filled in by x->type->output and skb->nh will be set to the nextheader field
36 * of the extension header directly preceding the encapsulation header, or in
37 * its absence, that of the top IP header. The value of skb->data will always
38 * point to the top IP header.
39 */
Jamal Hadi Salimeb878e82006-08-31 17:42:59 -070040static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
Herbert Xub59f45d2006-05-27 23:05:54 -070041{
42 struct dst_entry *dst = skb->dst;
Herbert Xub59f45d2006-05-27 23:05:54 -070043 struct ipv6hdr *iph, *top_iph;
44 int dsfield;
45
46 skb_push(skb, x->props.header_len);
47 iph = skb->nh.ipv6h;
48
49 skb->nh.raw = skb->data;
50 top_iph = skb->nh.ipv6h;
51 skb->nh.raw = &top_iph->nexthdr;
52 skb->h.ipv6h = top_iph + 1;
53
54 top_iph->version = 6;
55 top_iph->priority = iph->priority;
56 top_iph->flow_lbl[0] = iph->flow_lbl[0];
57 top_iph->flow_lbl[1] = iph->flow_lbl[1];
58 top_iph->flow_lbl[2] = iph->flow_lbl[2];
59 dsfield = ipv6_get_dsfield(top_iph);
60 dsfield = INET_ECN_encapsulate(dsfield, dsfield);
61 if (x->props.flags & XFRM_STATE_NOECN)
62 dsfield &= ~INET_ECN_MASK;
63 ipv6_change_dsfield(top_iph, 0, dsfield);
64 top_iph->nexthdr = IPPROTO_IPV6;
65 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
66 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
67 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
68 return 0;
69}
70
71static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
72{
73 int err = -EINVAL;
74
75 if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6)
76 goto out;
77 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
78 goto out;
79
80 if (skb_cloned(skb) &&
81 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
82 goto out;
83
84 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
85 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
86 if (!(x->props.flags & XFRM_STATE_NOECN))
87 ipip6_ecn_decapsulate(skb);
88 skb->mac.raw = memmove(skb->data - skb->mac_len,
89 skb->mac.raw, skb->mac_len);
90 skb->nh.raw = skb->data;
91 err = 0;
92
93out:
94 return err;
95}
96
97static struct xfrm_mode xfrm6_tunnel_mode = {
98 .input = xfrm6_tunnel_input,
99 .output = xfrm6_tunnel_output,
100 .owner = THIS_MODULE,
101 .encap = XFRM_MODE_TUNNEL,
102};
103
104static int __init xfrm6_tunnel_init(void)
105{
106 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
107}
108
109static void __exit xfrm6_tunnel_exit(void)
110{
111 int err;
112
113 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
114 BUG_ON(err);
115}
116
117module_init(xfrm6_tunnel_init);
118module_exit(xfrm6_tunnel_exit);
119MODULE_LICENSE("GPL");
120MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);