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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 | { | |
a92df254 | 28 | struct net *net = dev_net(skb->dev); |
a94cfd19 | 29 | __be32 spi; |
b71d1d42 | 30 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
1da177e4 LT |
31 | struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); |
32 | struct xfrm_state *x; | |
33 | ||
55be7a9c DM |
34 | 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: | |
1da177e4 | 41 | return; |
55be7a9c | 42 | } |
1da177e4 | 43 | |
4195f814 | 44 | spi = htonl(ntohs(ipch->cpi)); |
b71d1d42 | 45 | x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, |
e905a9ed | 46 | spi, IPPROTO_COMP, AF_INET); |
1da177e4 LT |
47 | if (!x) |
48 | return; | |
55be7a9c DM |
49 | |
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); | |
1da177e4 LT |
54 | xfrm_state_put(x); |
55 | } | |
56 | ||
e905a9ed | 57 | /* We always hold one tunnel user reference to indicate a tunnel */ |
1da177e4 LT |
58 | static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
59 | { | |
a92df254 | 60 | struct net *net = xs_net(x); |
1da177e4 | 61 | struct xfrm_state *t; |
e905a9ed | 62 | |
a92df254 | 63 | t = xfrm_state_alloc(net); |
1da177e4 LT |
64 | 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; | |
e40b3286 | 72 | t->props.mode = x->props.mode; |
1da177e4 LT |
73 | t->props.saddr.a4 = x->props.saddr.a4; |
74 | t->props.flags = x->props.flags; | |
bd55775c | 75 | memcpy(&t->mark, &x->mark, sizeof(t->mark)); |
72cb6962 HX |
76 | |
77 | if (xfrm_init_state(t)) | |
1da177e4 LT |
78 | goto error; |
79 | ||
1da177e4 LT |
80 | atomic_set(&t->tunnel_users, 1); |
81 | out: | |
82 | return t; | |
83 | ||
84 | error: | |
85 | t->km.state = XFRM_STATE_DEAD; | |
86 | xfrm_state_put(t); | |
87 | t = NULL; | |
88 | goto out; | |
89 | } | |
90 | ||
91 | /* | |
4a3e2f71 | 92 | * Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
1da177e4 LT |
93 | * always incremented on success. |
94 | */ | |
95 | static int ipcomp_tunnel_attach(struct xfrm_state *x) | |
96 | { | |
a92df254 | 97 | struct net *net = xs_net(x); |
1da177e4 LT |
98 | int err = 0; |
99 | struct xfrm_state *t; | |
bd55775c | 100 | u32 mark = x->mark.v & x->mark.m; |
1da177e4 | 101 | |
bd55775c | 102 | t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4, |
e905a9ed | 103 | x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
1da177e4 LT |
104 | 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); | |
115 | out: | |
116 | return err; | |
117 | } | |
118 | ||
6fccab67 | 119 | static int ipcomp4_init_state(struct xfrm_state *x) |
1da177e4 | 120 | { |
2c3abab7 | 121 | int err = -EINVAL; |
1da177e4 | 122 | |
e40b3286 HX |
123 | 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 | ||
6fccab67 HX |
134 | err = ipcomp_init_state(x); |
135 | if (err) | |
1da177e4 LT |
136 | goto out; |
137 | ||
7e49e6de | 138 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
139 | err = ipcomp_tunnel_attach(x); |
140 | if (err) | |
10e7454e | 141 | goto out; |
1da177e4 LT |
142 | } |
143 | ||
1da177e4 LT |
144 | err = 0; |
145 | out: | |
146 | return err; | |
1da177e4 LT |
147 | } |
148 | ||
533cb5b0 | 149 | static const struct xfrm_type ipcomp_type = { |
1da177e4 LT |
150 | .description = "IPCOMP4", |
151 | .owner = THIS_MODULE, | |
152 | .proto = IPPROTO_COMP, | |
6fccab67 | 153 | .init_state = ipcomp4_init_state, |
1da177e4 LT |
154 | .destructor = ipcomp_destroy, |
155 | .input = ipcomp_input, | |
156 | .output = ipcomp_output | |
157 | }; | |
158 | ||
32613090 | 159 | static const struct net_protocol ipcomp4_protocol = { |
1da177e4 LT |
160 | .handler = xfrm4_rcv, |
161 | .err_handler = ipcomp4_err, | |
162 | .no_policy = 1, | |
163 | }; | |
164 | ||
165 | static int __init ipcomp4_init(void) | |
166 | { | |
167 | if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { | |
058bd4d2 | 168 | pr_info("%s: can't add xfrm type\n", __func__); |
1da177e4 LT |
169 | return -EAGAIN; |
170 | } | |
171 | if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) { | |
058bd4d2 | 172 | pr_info("%s: can't add protocol\n", __func__); |
1da177e4 LT |
173 | xfrm_unregister_type(&ipcomp_type, AF_INET); |
174 | return -EAGAIN; | |
175 | } | |
176 | return 0; | |
177 | } | |
178 | ||
179 | static void __exit ipcomp4_fini(void) | |
180 | { | |
181 | if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) | |
058bd4d2 | 182 | pr_info("%s: can't remove protocol\n", __func__); |
1da177e4 | 183 | if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0) |
058bd4d2 | 184 | pr_info("%s: can't remove xfrm type\n", __func__); |
1da177e4 LT |
185 | } |
186 | ||
187 | module_init(ipcomp4_init); | |
188 | module_exit(ipcomp4_fini); | |
189 | ||
190 | MODULE_LICENSE("GPL"); | |
6fccab67 | 191 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173"); |
1da177e4 LT |
192 | MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>"); |
193 | ||
d3d6dd3a | 194 | MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP); |