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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{
Al Viroa94cfd12006-09-27 18:47:24 -070028 __be32 spi;
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 struct iphdr *iph = (struct iphdr *)skb->data;
30 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
31 struct xfrm_state *x;
32
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -030033 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
34 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 return;
36
Alexey Dobriyan4195f812006-05-22 16:53:22 -070037 spi = htonl(ntohs(ipch->cpi));
Alexey Dobriyan221df1e2008-11-25 17:30:50 -080038 x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090039 spi, IPPROTO_COMP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 if (!x)
41 return;
Harvey Harrison673d57e2008-10-31 00:53:57 -070042 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
43 spi, &iph->daddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 xfrm_state_put(x);
45}
46
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090047/* We always hold one tunnel user reference to indicate a tunnel */
Linus Torvalds1da177e2005-04-16 15:20:36 -070048static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
49{
50 struct xfrm_state *t;
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090051
Alexey Dobriyan673c09b2008-11-25 17:15:16 -080052 t = xfrm_state_alloc(&init_net);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 if (t == NULL)
54 goto out;
55
56 t->id.proto = IPPROTO_IPIP;
57 t->id.spi = x->props.saddr.a4;
58 t->id.daddr.a4 = x->id.daddr.a4;
59 memcpy(&t->sel, &x->sel, sizeof(t->sel));
60 t->props.family = AF_INET;
Herbert Xue40b3282007-11-13 21:39:08 -080061 t->props.mode = x->props.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 t->props.saddr.a4 = x->props.saddr.a4;
63 t->props.flags = x->props.flags;
Herbert Xu72cb6962005-06-20 13:18:08 -070064
65 if (xfrm_init_state(t))
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 goto error;
67
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 atomic_set(&t->tunnel_users, 1);
69out:
70 return t;
71
72error:
73 t->km.state = XFRM_STATE_DEAD;
74 xfrm_state_put(t);
75 t = NULL;
76 goto out;
77}
78
79/*
Arjan van de Ven4a3e2f72006-03-20 22:33:17 -080080 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 * always incremented on success.
82 */
83static int ipcomp_tunnel_attach(struct xfrm_state *x)
84{
85 int err = 0;
86 struct xfrm_state *t;
87
Alexey Dobriyan221df1e2008-11-25 17:30:50 -080088 t = xfrm_state_lookup(&init_net, (xfrm_address_t *)&x->id.daddr.a4,
YOSHIFUJI Hideakie905a9e2007-02-09 23:24:47 +090089 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 if (!t) {
91 t = ipcomp_tunnel_create(x);
92 if (!t) {
93 err = -EINVAL;
94 goto out;
95 }
96 xfrm_state_insert(t);
97 xfrm_state_hold(t);
98 }
99 x->tunnel = t;
100 atomic_inc(&t->tunnel_users);
101out:
102 return err;
103}
104
Herbert Xu6fccab62008-07-25 02:54:40 -0700105static int ipcomp4_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106{
David S. Miller2c3abab2008-07-27 03:59:24 -0700107 int err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Herbert Xue40b3282007-11-13 21:39:08 -0800109 x->props.header_len = 0;
110 switch (x->props.mode) {
111 case XFRM_MODE_TRANSPORT:
112 break;
113 case XFRM_MODE_TUNNEL:
114 x->props.header_len += sizeof(struct iphdr);
115 break;
116 default:
117 goto out;
118 }
119
Herbert Xu6fccab62008-07-25 02:54:40 -0700120 err = ipcomp_init_state(x);
121 if (err)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 goto out;
123
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700124 if (x->props.mode == XFRM_MODE_TUNNEL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 err = ipcomp_tunnel_attach(x);
126 if (err)
127 goto error_tunnel;
128 }
129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 err = 0;
131out:
132 return err;
133
134error_tunnel:
Herbert Xu6fccab62008-07-25 02:54:40 -0700135 ipcomp_destroy(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 goto out;
137}
138
Eric Dumazet533cb5b2008-01-30 19:11:50 -0800139static const struct xfrm_type ipcomp_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 .description = "IPCOMP4",
141 .owner = THIS_MODULE,
142 .proto = IPPROTO_COMP,
Herbert Xu6fccab62008-07-25 02:54:40 -0700143 .init_state = ipcomp4_init_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 .destructor = ipcomp_destroy,
145 .input = ipcomp_input,
146 .output = ipcomp_output
147};
148
Alexey Dobriyan32613092009-09-14 12:21:47 +0000149static const struct net_protocol ipcomp4_protocol = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 .handler = xfrm4_rcv,
151 .err_handler = ipcomp4_err,
152 .no_policy = 1,
153};
154
155static int __init ipcomp4_init(void)
156{
157 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
158 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
159 return -EAGAIN;
160 }
161 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
162 printk(KERN_INFO "ipcomp init: can't add protocol\n");
163 xfrm_unregister_type(&ipcomp_type, AF_INET);
164 return -EAGAIN;
165 }
166 return 0;
167}
168
169static void __exit ipcomp4_fini(void)
170{
171 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
172 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
173 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
174 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
175}
176
177module_init(ipcomp4_init);
178module_exit(ipcomp4_fini);
179
180MODULE_LICENSE("GPL");
Herbert Xu6fccab62008-07-25 02:54:40 -0700181MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
183
Masahide NAKAMURAd3d6dd32007-06-26 23:57:49 -0700184MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);