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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
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -030034 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
35 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 return;
37
Alexey Dobriyan4195f812006-05-22 16:53:22 -070038 spi = htonl(ntohs(ipch->cpi));
Eric Dumazetb71d1d42011-04-22 04:53:02 +000039 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090040 spi, IPPROTO_COMP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 if (!x)
42 return;
Harvey Harrison673d57e2008-10-31 00:53:57 -070043 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
44 spi, &iph->daddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 xfrm_state_put(x);
46}
47
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090048/* We always hold one tunnel user reference to indicate a tunnel */
Linus Torvalds1da177e2005-04-16 15:20:36 -070049static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
50{
Alexey Dobriyana92df252010-01-25 10:38:34 +000051 struct net *net = xs_net(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 struct xfrm_state *t;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090053
Alexey Dobriyana92df252010-01-25 10:38:34 +000054 t = xfrm_state_alloc(net);
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 if (t == NULL)
56 goto out;
57
58 t->id.proto = IPPROTO_IPIP;
59 t->id.spi = x->props.saddr.a4;
60 t->id.daddr.a4 = x->id.daddr.a4;
61 memcpy(&t->sel, &x->sel, sizeof(t->sel));
62 t->props.family = AF_INET;
Herbert Xue40b3282007-11-13 21:39:08 -080063 t->props.mode = x->props.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 t->props.saddr.a4 = x->props.saddr.a4;
65 t->props.flags = x->props.flags;
Jamal Hadi Salimbd557752010-02-22 16:20:22 -080066 memcpy(&t->mark, &x->mark, sizeof(t->mark));
Herbert Xu72cb6962005-06-20 13:18:08 -070067
68 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 goto error;
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 atomic_set(&t->tunnel_users, 1);
72out:
73 return t;
74
75error:
76 t->km.state = XFRM_STATE_DEAD;
77 xfrm_state_put(t);
78 t = NULL;
79 goto out;
80}
81
82/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080083 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 * always incremented on success.
85 */
86static int ipcomp_tunnel_attach(struct xfrm_state *x)
87{
Alexey Dobriyana92df252010-01-25 10:38:34 +000088 struct net *net = xs_net(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 int err = 0;
90 struct xfrm_state *t;
Jamal Hadi Salimbd557752010-02-22 16:20:22 -080091 u32 mark = x->mark.v & x->mark.m;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
Jamal Hadi Salimbd557752010-02-22 16:20:22 -080093 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090094 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 if (!t) {
96 t = ipcomp_tunnel_create(x);
97 if (!t) {
98 err = -EINVAL;
99 goto out;
100 }
101 xfrm_state_insert(t);
102 xfrm_state_hold(t);
103 }
104 x->tunnel = t;
105 atomic_inc(&t->tunnel_users);
106out:
107 return err;
108}
109
Herbert Xu6fccab62008-07-25 02:54:40 -0700110static int ipcomp4_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111{
David S. Miller2c3abab2008-07-27 03:59:24 -0700112 int err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
Herbert Xue40b3282007-11-13 21:39:08 -0800114 x->props.header_len = 0;
115 switch (x->props.mode) {
116 case XFRM_MODE_TRANSPORT:
117 break;
118 case XFRM_MODE_TUNNEL:
119 x->props.header_len += sizeof(struct iphdr);
120 break;
121 default:
122 goto out;
123 }
124
Herbert Xu6fccab62008-07-25 02:54:40 -0700125 err = ipcomp_init_state(x);
126 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 goto out;
128
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700129 if (x->props.mode == XFRM_MODE_TUNNEL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 err = ipcomp_tunnel_attach(x);
131 if (err)
Herbert Xu10e74542010-02-15 19:24:30 +0000132 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 err = 0;
136out:
137 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138}
139
Eric Dumazet533cb5b2008-01-30 19:11:50 -0800140static const struct xfrm_type ipcomp_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 .description = "IPCOMP4",
142 .owner = THIS_MODULE,
143 .proto = IPPROTO_COMP,
Herbert Xu6fccab62008-07-25 02:54:40 -0700144 .init_state = ipcomp4_init_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 .destructor = ipcomp_destroy,
146 .input = ipcomp_input,
147 .output = ipcomp_output
148};
149
Alexey Dobriyan32613092009-09-14 12:21:47 +0000150static const struct net_protocol ipcomp4_protocol = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 .handler = xfrm4_rcv,
152 .err_handler = ipcomp4_err,
153 .no_policy = 1,
154};
155
156static int __init ipcomp4_init(void)
157{
158 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
Joe Perches058bd4d2012-03-11 18:36:11 +0000159 pr_info("%s: can't add xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 return -EAGAIN;
161 }
162 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
Joe Perches058bd4d2012-03-11 18:36:11 +0000163 pr_info("%s: can't add protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 xfrm_unregister_type(&ipcomp_type, AF_INET);
165 return -EAGAIN;
166 }
167 return 0;
168}
169
170static void __exit ipcomp4_fini(void)
171{
172 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
Joe Perches058bd4d2012-03-11 18:36:11 +0000173 pr_info("%s: can't remove protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
Joe Perches058bd4d2012-03-11 18:36:11 +0000175 pr_info("%s: can't remove xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176}
177
178module_init(ipcomp4_init);
179module_exit(ipcomp4_fini);
180
181MODULE_LICENSE("GPL");
Herbert Xu6fccab62008-07-25 02:54:40 -0700182MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
184
Masahide NAKAMURAd3d6dd32007-06-26 23:57:49 -0700185MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);