Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | |
e905a9ed | 8 | * Software Foundation; either version 2 of the License, or (at your option) |
1da177e4 LT |
9 | * any later version. |
10 | * | |
11 | * Todo: | |
12 | * - Tunable compression parameters. | |
13 | * - Compression stats. | |
14 | * - Adaptive compression. | |
15 | */ | |
1da177e4 | 16 | #include <linux/module.h> |
4999f362 | 17 | #include <linux/err.h> |
1da177e4 LT |
18 | #include <linux/rtnetlink.h> |
19 | #include <net/ip.h> | |
20 | #include <net/xfrm.h> | |
21 | #include <net/icmp.h> | |
22 | #include <net/ipcomp.h> | |
14c85021 | 23 | #include <net/protocol.h> |
6fccab67 | 24 | #include <net/sock.h> |
1da177e4 LT |
25 | |
26 | static void ipcomp4_err(struct sk_buff *skb, u32 info) | |
27 | { | |
a94cfd19 | 28 | __be32 spi; |
1da177e4 LT |
29 | 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 | ||
88c7664f ACM |
33 | if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH || |
34 | icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) | |
1da177e4 LT |
35 | return; |
36 | ||
4195f814 | 37 | spi = htonl(ntohs(ipch->cpi)); |
221df1ed | 38 | x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr, |
e905a9ed | 39 | spi, IPPROTO_COMP, AF_INET); |
1da177e4 LT |
40 | if (!x) |
41 | return; | |
673d57e7 HH |
42 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n", |
43 | spi, &iph->daddr); | |
1da177e4 LT |
44 | xfrm_state_put(x); |
45 | } | |
46 | ||
e905a9ed | 47 | /* We always hold one tunnel user reference to indicate a tunnel */ |
1da177e4 LT |
48 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
49 | { | |
50 | struct xfrm_state *t; | |
e905a9ed | 51 | |
673c09be | 52 | t = xfrm_state_alloc(&init_net); |
1da177e4 LT |
53 | 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; | |
e40b3286 | 61 | t->props.mode = x->props.mode; |
1da177e4 LT |
62 | t->props.saddr.a4 = x->props.saddr.a4; |
63 | t->props.flags = x->props.flags; | |
72cb6962 HX |
64 | |
65 | if (xfrm_init_state(t)) | |
1da177e4 LT |
66 | goto error; |
67 | ||
1da177e4 LT |
68 | atomic_set(&t->tunnel_users, 1); |
69 | out: | |
70 | return t; | |
71 | ||
72 | error: | |
73 | t->km.state = XFRM_STATE_DEAD; | |
74 | xfrm_state_put(t); | |
75 | t = NULL; | |
76 | goto out; | |
77 | } | |
78 | ||
79 | /* | |
4a3e2f71 | 80 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
81 | * always incremented on success. |
82 | */ | |
83 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
84 | { | |
85 | int err = 0; | |
86 | struct xfrm_state *t; | |
87 | ||
221df1ed | 88 | t = xfrm_state_lookup(&init_net, (xfrm_address_t *)&x->id.daddr.a4, |
e905a9ed | 89 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
1da177e4 LT |
90 | 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); | |
101 | out: | |
102 | return err; | |
103 | } | |
104 | ||
6fccab67 | 105 | static int ipcomp4_init_state(struct xfrm_state *x) |
1da177e4 | 106 | { |
2c3abab7 | 107 | int err = -EINVAL; |
1da177e4 | 108 | |
e40b3286 HX |
109 | 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 | ||
6fccab67 HX |
120 | err = ipcomp_init_state(x); |
121 | if (err) | |
1da177e4 LT |
122 | goto out; |
123 | ||
7e49e6de | 124 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
125 | err = ipcomp_tunnel_attach(x); |
126 | if (err) | |
127 | goto error_tunnel; | |
128 | } | |
129 | ||
1da177e4 LT |
130 | err = 0; |
131 | out: | |
132 | return err; | |
133 | ||
134 | error_tunnel: | |
6fccab67 | 135 | ipcomp_destroy(x); |
1da177e4 LT |
136 | goto out; |
137 | } | |
138 | ||
533cb5b0 | 139 | static const struct xfrm_type ipcomp_type = { |
1da177e4 LT |
140 | .description = "IPCOMP4", |
141 | .owner = THIS_MODULE, | |
142 | .proto = IPPROTO_COMP, | |
6fccab67 | 143 | .init_state = ipcomp4_init_state, |
1da177e4 LT |
144 | .destructor = ipcomp_destroy, |
145 | .input = ipcomp_input, | |
146 | .output = ipcomp_output | |
147 | }; | |
148 | ||
149 | static struct net_protocol ipcomp4_protocol = { | |
150 | .handler = xfrm4_rcv, | |
151 | .err_handler = ipcomp4_err, | |
152 | .no_policy = 1, | |
153 | }; | |
154 | ||
155 | static 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 | ||
169 | static 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 | ||
177 | module_init(ipcomp4_init); | |
178 | module_exit(ipcomp4_fini); | |
179 | ||
180 | MODULE_LICENSE("GPL"); | |
6fccab67 | 181 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173"); |
1da177e4 LT |
182 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |
183 | ||
d3d6dd3a | 184 | MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP); |