blob: 91771a7c802f828c33429413674c5f78ca393b6f [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
Nicolas Dichtela947b0a2013-02-22 10:54:54 +010047 /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
48 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
49 top_iph->tos = 0;
50 else
51 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
52 top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
Herbert Xu36cf9ac2007-11-13 21:40:52 -080053 XFRM_MODE_SKB_CB(skb)->tos);
Miika Komuc82f9632007-02-06 14:27:02 -080054
Herbert Xu36cf9ac2007-11-13 21:40:52 -080055 flags = x->props.flags;
Herbert Xub59f45d2006-05-27 23:05:54 -070056 if (flags & XFRM_STATE_NOECN)
57 IP_ECN_clear(top_iph);
58
Herbert Xu36cf9ac2007-11-13 21:40:52 -080059 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
Steffen Klassertfe833fc2008-06-17 16:37:13 -070060 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
Herbert Xub59f45d2006-05-27 23:05:54 -070061
David S. Miller323e1262010-12-12 21:55:08 -080062 top_iph->ttl = ip4_dst_hoplimit(dst->child);
Herbert Xub59f45d2006-05-27 23:05:54 -070063
64 top_iph->saddr = x->props.saddr.a4;
65 top_iph->daddr = x->id.daddr.a4;
Eric Dumazet73f156a2014-06-02 05:26:03 -070066 ip_select_ident(skb, NULL);
Herbert Xub59f45d2006-05-27 23:05:54 -070067
Herbert Xub59f45d2006-05-27 23:05:54 -070068 return 0;
69}
70
Herbert Xu195ad6a2007-12-20 13:53:40 -080071static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
Herbert Xub59f45d2006-05-27 23:05:54 -070072{
Herbert Xub59f45d2006-05-27 23:05:54 -070073 int err = -EINVAL;
74
Herbert Xu227620e2007-11-13 21:41:28 -080075 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
76 goto out;
Miika Komuc82f9632007-02-06 14:27:02 -080077
Herbert Xub59f45d2006-05-27 23:05:54 -070078 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
79 goto out;
80
stephen hemminger9aac22d2013-02-16 07:40:29 +000081 err = skb_unclone(skb, GFP_ATOMIC);
82 if (err)
Herbert Xub59f45d2006-05-27 23:05:54 -070083 goto out;
84
Herbert Xu227620e2007-11-13 21:41:28 -080085 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
86 ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
87 if (!(x->props.flags & XFRM_STATE_NOECN))
88 ipip_ecn_decapsulate(skb);
89
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -070090 skb_reset_network_header(skb);
Eric Dumazet03606892012-02-23 10:55:02 +000091 skb_mac_header_rebuild(skb);
92
Herbert Xub59f45d2006-05-27 23:05:54 -070093 err = 0;
94
95out:
96 return err;
97}
98
99static struct xfrm_mode xfrm4_tunnel_mode = {
Herbert Xu195ad6a2007-12-20 13:53:40 -0800100 .input2 = xfrm4_mode_tunnel_input,
Herbert Xu227620e2007-11-13 21:41:28 -0800101 .input = xfrm_prepare_input,
Herbert Xu195ad6a2007-12-20 13:53:40 -0800102 .output2 = xfrm4_mode_tunnel_output,
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800103 .output = xfrm4_prepare_output,
Herbert Xub59f45d2006-05-27 23:05:54 -0700104 .owner = THIS_MODULE,
105 .encap = XFRM_MODE_TUNNEL,
Herbert Xu1bfcb102007-10-17 21:31:50 -0700106 .flags = XFRM_MODE_FLAG_TUNNEL,
Herbert Xub59f45d2006-05-27 23:05:54 -0700107};
108
Herbert Xu195ad6a2007-12-20 13:53:40 -0800109static int __init xfrm4_mode_tunnel_init(void)
Herbert Xub59f45d2006-05-27 23:05:54 -0700110{
111 return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
112}
113
Herbert Xu195ad6a2007-12-20 13:53:40 -0800114static void __exit xfrm4_mode_tunnel_exit(void)
Herbert Xub59f45d2006-05-27 23:05:54 -0700115{
116 int err;
117
118 err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
119 BUG_ON(err);
120}
121
Herbert Xu195ad6a2007-12-20 13:53:40 -0800122module_init(xfrm4_mode_tunnel_init);
123module_exit(xfrm4_mode_tunnel_exit);
Herbert Xub59f45d2006-05-27 23:05:54 -0700124MODULE_LICENSE("GPL");
125MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);