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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * IP Payload Compression Protocol (IPComp) - RFC3173.
3 *
4 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +09008 * Software Foundation; either version 2 of the License, or (at your option)
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * any later version.
10 *
11 * Todo:
12 * - Tunable compression parameters.
13 * - Compression stats.
14 * - Adaptive compression.
15 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
Herbert Xu4999f362007-11-07 02:21:47 -080017#include <linux/err.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/rtnetlink.h>
19#include <net/ip.h>
20#include <net/xfrm.h>
21#include <net/icmp.h>
22#include <net/ipcomp.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020023#include <net/protocol.h>
Herbert Xu6fccab62008-07-25 02:54:40 -070024#include <net/sock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26static void ipcomp4_err(struct sk_buff *skb, u32 info)
27{
Alexey Dobriyana92df252010-01-25 10:38:34 +000028 struct net *net = dev_net(skb->dev);
Al Viroa94cfd12006-09-27 18:47:24 -070029 __be32 spi;
Eric Dumazetb71d1d42011-04-22 04:53:02 +000030 const struct iphdr *iph = (const struct iphdr *)skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
32 struct xfrm_state *x;
33
David S. Miller55be7a92012-07-11 21:27:49 -070034 switch (icmp_hdr(skb)->type) {
35 case ICMP_DEST_UNREACH:
36 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
37 return;
38 case ICMP_REDIRECT:
39 break;
40 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 return;
David S. Miller55be7a92012-07-11 21:27:49 -070042 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
Alexey Dobriyan4195f812006-05-22 16:53:22 -070044 spi = htonl(ntohs(ipch->cpi));
Eric Dumazetb71d1d42011-04-22 04:53:02 +000045 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090046 spi, IPPROTO_COMP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 if (!x)
48 return;
David S. Miller55be7a92012-07-11 21:27:49 -070049
50 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
51 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
52 else
53 ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 xfrm_state_put(x);
55}
56
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090057/* We always hold one tunnel user reference to indicate a tunnel */
Linus Torvalds1da177e2005-04-16 15:20:36 -070058static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
59{
Alexey Dobriyana92df252010-01-25 10:38:34 +000060 struct net *net = xs_net(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 struct xfrm_state *t;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090062
Alexey Dobriyana92df252010-01-25 10:38:34 +000063 t = xfrm_state_alloc(net);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 if (t == NULL)
65 goto out;
66
67 t->id.proto = IPPROTO_IPIP;
68 t->id.spi = x->props.saddr.a4;
69 t->id.daddr.a4 = x->id.daddr.a4;
70 memcpy(&t->sel, &x->sel, sizeof(t->sel));
71 t->props.family = AF_INET;
Herbert Xue40b3282007-11-13 21:39:08 -080072 t->props.mode = x->props.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 t->props.saddr.a4 = x->props.saddr.a4;
74 t->props.flags = x->props.flags;
Jamal Hadi Salimbd557752010-02-22 16:20:22 -080075 memcpy(&t->mark, &x->mark, sizeof(t->mark));
Herbert Xu72cb6962005-06-20 13:18:08 -070076
77 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 goto error;
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 atomic_set(&t->tunnel_users, 1);
81out:
82 return t;
83
84error:
85 t->km.state = XFRM_STATE_DEAD;
86 xfrm_state_put(t);
87 t = NULL;
88 goto out;
89}
90
91/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080092 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 * always incremented on success.
94 */
95static int ipcomp_tunnel_attach(struct xfrm_state *x)
96{
Alexey Dobriyana92df252010-01-25 10:38:34 +000097 struct net *net = xs_net(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 int err = 0;
99 struct xfrm_state *t;
Jamal Hadi Salimbd557752010-02-22 16:20:22 -0800100 u32 mark = x->mark.v & x->mark.m;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Jamal Hadi Salimbd557752010-02-22 16:20:22 -0800102 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +0900103 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 if (!t) {
105 t = ipcomp_tunnel_create(x);
106 if (!t) {
107 err = -EINVAL;
108 goto out;
109 }
110 xfrm_state_insert(t);
111 xfrm_state_hold(t);
112 }
113 x->tunnel = t;
114 atomic_inc(&t->tunnel_users);
115out:
116 return err;
117}
118
Herbert Xu6fccab62008-07-25 02:54:40 -0700119static int ipcomp4_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
David S. Miller2c3abab2008-07-27 03:59:24 -0700121 int err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
Herbert Xue40b3282007-11-13 21:39:08 -0800123 x->props.header_len = 0;
124 switch (x->props.mode) {
125 case XFRM_MODE_TRANSPORT:
126 break;
127 case XFRM_MODE_TUNNEL:
128 x->props.header_len += sizeof(struct iphdr);
129 break;
130 default:
131 goto out;
132 }
133
Herbert Xu6fccab62008-07-25 02:54:40 -0700134 err = ipcomp_init_state(x);
135 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 goto out;
137
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700138 if (x->props.mode == XFRM_MODE_TUNNEL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 err = ipcomp_tunnel_attach(x);
140 if (err)
Herbert Xu10e74542010-02-15 19:24:30 +0000141 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 }
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 err = 0;
145out:
146 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
Eric Dumazet533cb5b2008-01-30 19:11:50 -0800149static const struct xfrm_type ipcomp_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 .description = "IPCOMP4",
151 .owner = THIS_MODULE,
152 .proto = IPPROTO_COMP,
Herbert Xu6fccab62008-07-25 02:54:40 -0700153 .init_state = ipcomp4_init_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 .destructor = ipcomp_destroy,
155 .input = ipcomp_input,
156 .output = ipcomp_output
157};
158
Alexey Dobriyan32613092009-09-14 12:21:47 +0000159static const struct net_protocol ipcomp4_protocol = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 .handler = xfrm4_rcv,
161 .err_handler = ipcomp4_err,
162 .no_policy = 1,
163};
164
165static int __init ipcomp4_init(void)
166{
167 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
Joe Perches058bd4d2012-03-11 18:36:11 +0000168 pr_info("%s: can't add xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 return -EAGAIN;
170 }
171 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
Joe Perches058bd4d2012-03-11 18:36:11 +0000172 pr_info("%s: can't add protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 xfrm_unregister_type(&ipcomp_type, AF_INET);
174 return -EAGAIN;
175 }
176 return 0;
177}
178
179static void __exit ipcomp4_fini(void)
180{
181 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
Joe Perches058bd4d2012-03-11 18:36:11 +0000182 pr_info("%s: can't remove protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
Joe Perches058bd4d2012-03-11 18:36:11 +0000184 pr_info("%s: can't remove xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185}
186
187module_init(ipcomp4_init);
188module_exit(ipcomp4_fini);
189
190MODULE_LICENSE("GPL");
Herbert Xu6fccab62008-07-25 02:54:40 -0700191MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
193
Masahide NAKAMURAd3d6dd32007-06-26 23:57:49 -0700194MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);