blob: 6f368413eb0e6b35bdb4500f175372809f43a18d [file] [log] [blame]
Herbert Xub59f45d2006-05-27 23:05:54 -07001/*
2 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
3 *
4 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
5 */
6
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09007#include <linux/gfp.h>
Herbert Xub59f45d2006-05-27 23:05:54 -07008#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/dst.h>
14#include <net/inet_ecn.h>
15#include <net/ip.h>
16#include <net/xfrm.h>
17
18static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
19{
Arnaldo Carvalho de Melob0061ce2007-04-25 18:02:22 -070020 struct iphdr *inner_iph = ipip_hdr(skb);
Herbert Xub59f45d2006-05-27 23:05:54 -070021
Herbert Xu227620e2007-11-13 21:41:28 -080022 if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
Herbert Xub59f45d2006-05-27 23:05:54 -070023 IP_ECN_set_ce(inner_iph);
24}
25
26/* Add encapsulation header.
27 *
Herbert Xuceb1eec82007-10-10 15:45:52 -070028 * The top IP header will be constructed per RFC 2401.
Herbert Xub59f45d2006-05-27 23:05:54 -070029 */
Herbert Xu195ad6a2007-12-20 13:53:40 -080030static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
Herbert Xub59f45d2006-05-27 23:05:54 -070031{
Eric Dumazetadf30902009-06-02 05:19:30 +000032 struct dst_entry *dst = skb_dst(skb);
Herbert Xu36cf9ac2007-11-13 21:40:52 -080033 struct iphdr *top_iph;
Herbert Xub59f45d2006-05-27 23:05:54 -070034 int flags;
35
Herbert Xu7b277b12007-10-10 15:44:06 -070036 skb_set_network_header(skb, -x->props.header_len);
Herbert Xu37fedd32007-10-10 15:44:44 -070037 skb->mac_header = skb->network_header +
38 offsetof(struct iphdr, protocol);
Herbert Xu36cf9ac2007-11-13 21:40:52 -080039 skb->transport_header = skb->network_header + sizeof(*top_iph);
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -070040 top_iph = ip_hdr(skb);
Herbert Xub59f45d2006-05-27 23:05:54 -070041
42 top_iph->ihl = 5;
43 top_iph->version = 4;
44
Eric Dumazetadf30902009-06-02 05:19:30 +000045 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
Miika Komuc82f9632007-02-06 14:27:02 -080046
47 /* DS disclosed */
Herbert Xu36cf9ac2007-11-13 21:40:52 -080048 top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos,
49 XFRM_MODE_SKB_CB(skb)->tos);
Miika Komuc82f9632007-02-06 14:27:02 -080050
Herbert Xu36cf9ac2007-11-13 21:40:52 -080051 flags = x->props.flags;
Herbert Xub59f45d2006-05-27 23:05:54 -070052 if (flags & XFRM_STATE_NOECN)
53 IP_ECN_clear(top_iph);
54
Herbert Xu36cf9ac2007-11-13 21:40:52 -080055 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
Steffen Klassertfe833fc2008-06-17 16:37:13 -070056 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
Herbert Xu36cf9ac2007-11-13 21:40:52 -080057 ip_select_ident(top_iph, dst->child, NULL);
Herbert Xub59f45d2006-05-27 23:05:54 -070058
59 top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
60
61 top_iph->saddr = x->props.saddr.a4;
62 top_iph->daddr = x->id.daddr.a4;
Herbert Xub59f45d2006-05-27 23:05:54 -070063
Herbert Xub59f45d2006-05-27 23:05:54 -070064 return 0;
65}
66
Herbert Xu195ad6a2007-12-20 13:53:40 -080067static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
Herbert Xub59f45d2006-05-27 23:05:54 -070068{
Arnaldo Carvalho de Melo39f69c62007-03-10 12:40:27 -030069 const unsigned char *old_mac;
Herbert Xub59f45d2006-05-27 23:05:54 -070070 int err = -EINVAL;
71
Herbert Xu227620e2007-11-13 21:41:28 -080072 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
73 goto out;
Miika Komuc82f9632007-02-06 14:27:02 -080074
Herbert Xub59f45d2006-05-27 23:05:54 -070075 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
76 goto out;
77
78 if (skb_cloned(skb) &&
79 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
80 goto out;
81
Herbert Xu227620e2007-11-13 21:41:28 -080082 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
83 ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
84 if (!(x->props.flags & XFRM_STATE_NOECN))
85 ipip_ecn_decapsulate(skb);
86
Arnaldo Carvalho de Melo98e399f2007-03-19 15:33:04 -070087 old_mac = skb_mac_header(skb);
Arnaldo Carvalho de Melo39f69c62007-03-10 12:40:27 -030088 skb_set_mac_header(skb, -skb->mac_len);
Arnaldo Carvalho de Melo98e399f2007-03-19 15:33:04 -070089 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -070090 skb_reset_network_header(skb);
Herbert Xub59f45d2006-05-27 23:05:54 -070091 err = 0;
92
93out:
94 return err;
95}
96
97static struct xfrm_mode xfrm4_tunnel_mode = {
Herbert Xu195ad6a2007-12-20 13:53:40 -080098 .input2 = xfrm4_mode_tunnel_input,
Herbert Xu227620e2007-11-13 21:41:28 -080099 .input = xfrm_prepare_input,
Herbert Xu195ad6a2007-12-20 13:53:40 -0800100 .output2 = xfrm4_mode_tunnel_output,
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800101 .output = xfrm4_prepare_output,
Herbert Xub59f45d2006-05-27 23:05:54 -0700102 .owner = THIS_MODULE,
103 .encap = XFRM_MODE_TUNNEL,
Herbert Xu1bfcb102007-10-17 21:31:50 -0700104 .flags = XFRM_MODE_FLAG_TUNNEL,
Herbert Xub59f45d2006-05-27 23:05:54 -0700105};
106
Herbert Xu195ad6a2007-12-20 13:53:40 -0800107static int __init xfrm4_mode_tunnel_init(void)
Herbert Xub59f45d2006-05-27 23:05:54 -0700108{
109 return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
110}
111
Herbert Xu195ad6a2007-12-20 13:53:40 -0800112static void __exit xfrm4_mode_tunnel_exit(void)
Herbert Xub59f45d2006-05-27 23:05:54 -0700113{
114 int err;
115
116 err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
117 BUG_ON(err);
118}
119
Herbert Xu195ad6a2007-12-20 13:53:40 -0800120module_init(xfrm4_mode_tunnel_init);
121module_exit(xfrm4_mode_tunnel_exit);
Herbert Xub59f45d2006-05-27 23:05:54 -0700122MODULE_LICENSE("GPL");
123MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);