blob: d2c560c181a1c02dbcc92be2a394c0e40df589c2 [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
Miika Komu43372262007-02-06 14:27:32 -080028static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
29{
30 if (INET_ECN_is_ce(ipv6_get_dsfield(skb->nh.ipv6h)))
31 IP_ECN_set_ce(skb->h.ipiph);
32}
33
Herbert Xub59f45d2006-05-27 23:05:54 -070034/* Add encapsulation header.
35 *
36 * The top IP header will be constructed per RFC 2401. The following fields
37 * in it shall be filled in by x->type->output:
38 * payload_len
39 *
40 * On exit, skb->h will be set to the start of the encapsulation header to be
41 * filled in by x->type->output and skb->nh will be set to the nextheader field
42 * of the extension header directly preceding the encapsulation header, or in
43 * its absence, that of the top IP header. The value of skb->data will always
44 * point to the top IP header.
45 */
Jamal Hadi Salimeb878e82006-08-31 17:42:59 -070046static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
Herbert Xub59f45d2006-05-27 23:05:54 -070047{
48 struct dst_entry *dst = skb->dst;
Miika Komu43372262007-02-06 14:27:32 -080049 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
Herbert Xub59f45d2006-05-27 23:05:54 -070050 struct ipv6hdr *iph, *top_iph;
51 int dsfield;
52
53 skb_push(skb, x->props.header_len);
54 iph = skb->nh.ipv6h;
55
56 skb->nh.raw = skb->data;
57 top_iph = skb->nh.ipv6h;
58 skb->nh.raw = &top_iph->nexthdr;
59 skb->h.ipv6h = top_iph + 1;
60
61 top_iph->version = 6;
Miika Komu43372262007-02-06 14:27:32 -080062 if (xdst->route->ops->family == AF_INET6) {
63 top_iph->priority = iph->priority;
64 top_iph->flow_lbl[0] = iph->flow_lbl[0];
65 top_iph->flow_lbl[1] = iph->flow_lbl[1];
66 top_iph->flow_lbl[2] = iph->flow_lbl[2];
67 top_iph->nexthdr = IPPROTO_IPV6;
68 } else {
69 top_iph->priority = 0;
70 top_iph->flow_lbl[0] = 0;
71 top_iph->flow_lbl[1] = 0;
72 top_iph->flow_lbl[2] = 0;
73 top_iph->nexthdr = IPPROTO_IPIP;
74 }
Herbert Xub59f45d2006-05-27 23:05:54 -070075 dsfield = ipv6_get_dsfield(top_iph);
76 dsfield = INET_ECN_encapsulate(dsfield, dsfield);
77 if (x->props.flags & XFRM_STATE_NOECN)
78 dsfield &= ~INET_ECN_MASK;
79 ipv6_change_dsfield(top_iph, 0, dsfield);
Herbert Xub59f45d2006-05-27 23:05:54 -070080 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
81 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
82 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
83 return 0;
84}
85
86static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
87{
88 int err = -EINVAL;
Arnaldo Carvalho de Melo39f69c62007-03-10 12:40:27 -030089 const unsigned char *old_mac;
Herbert Xub59f45d2006-05-27 23:05:54 -070090
Miika Komu43372262007-02-06 14:27:32 -080091 if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6
92 && skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
Herbert Xub59f45d2006-05-27 23:05:54 -070093 goto out;
94 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
95 goto out;
96
97 if (skb_cloned(skb) &&
98 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
99 goto out;
100
Miika Komu43372262007-02-06 14:27:32 -0800101 if (skb->nh.raw[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
102 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
103 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
104 if (!(x->props.flags & XFRM_STATE_NOECN))
105 ipip6_ecn_decapsulate(skb);
106 } else {
107 if (!(x->props.flags & XFRM_STATE_NOECN))
108 ip6ip_ecn_decapsulate(skb);
109 skb->protocol = htons(ETH_P_IP);
110 }
Arnaldo Carvalho de Melo39f69c62007-03-10 12:40:27 -0300111 old_mac = skb->mac.raw;
112 skb_set_mac_header(skb, -skb->mac_len);
113 memmove(skb->mac.raw, old_mac, skb->mac_len);
Herbert Xub59f45d2006-05-27 23:05:54 -0700114 skb->nh.raw = skb->data;
115 err = 0;
116
117out:
118 return err;
119}
120
121static struct xfrm_mode xfrm6_tunnel_mode = {
122 .input = xfrm6_tunnel_input,
123 .output = xfrm6_tunnel_output,
124 .owner = THIS_MODULE,
125 .encap = XFRM_MODE_TUNNEL,
126};
127
128static int __init xfrm6_tunnel_init(void)
129{
130 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
131}
132
133static void __exit xfrm6_tunnel_exit(void)
134{
135 int err;
136
137 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
138 BUG_ON(err);
139}
140
141module_init(xfrm6_tunnel_init);
142module_exit(xfrm6_tunnel_exit);
143MODULE_LICENSE("GPL");
144MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);