1 /*
2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
3 *
4 * Copyright (C)2003 USAGI/WIDE Project
5 *
6 * Author Mitsuru KANDA <mk@linux-ipv6.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, see <http://www.gnu.org/licenses/>.
20 */
21 /*
22 * [Memo]
23 *
24 * Outbound:
25 * The compression of IP datagram MUST be done before AH/ESP processing,
26 * fragmentation, and the addition of Hop-by-Hop/Routing header.
27 *
28 * Inbound:
29 * The decompression of IP datagram MUST be done after the reassembly,
30 * AH/ESP processing.
31 */
32
33 #define pr_fmt(fmt) "IPv6: " fmt
34
35 #include <linux/module.h>
36 #include <net/ip.h>
37 #include <net/xfrm.h>
38 #include <net/ipcomp.h>
39 #include <linux/crypto.h>
40 #include <linux/err.h>
41 #include <linux/pfkeyv2.h>
42 #include <linux/random.h>
43 #include <linux/percpu.h>
44 #include <linux/smp.h>
45 #include <linux/list.h>
46 #include <linux/vmalloc.h>
47 #include <linux/rtnetlink.h>
48 #include <net/ip6_route.h>
49 #include <net/icmp.h>
50 #include <net/ipv6.h>
51 #include <net/protocol.h>
52 #include <linux/ipv6.h>
53 #include <linux/icmpv6.h>
54 #include <linux/mutex.h>
55
ipcomp6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)56 static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
57 u8 type, u8 code, int offset, __be32 info)
58 {
59 struct net *net = dev_net(skb->dev);
60 __be32 spi;
61 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
62 struct ip_comp_hdr *ipcomph =
63 (struct ip_comp_hdr *)(skb->data + offset);
64 struct xfrm_state *x;
65
66 if (type != ICMPV6_PKT_TOOBIG &&
67 type != NDISC_REDIRECT)
68 return 0;
69
70 spi = htonl(ntohs(ipcomph->cpi));
71 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
72 spi, IPPROTO_COMP, AF_INET6);
73 if (!x)
74 return 0;
75
76 if (type == NDISC_REDIRECT)
77 ip6_redirect(skb, net, skb->dev->ifindex, 0,
78 sock_net_uid(net, NULL));
79 else
80 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
81 xfrm_state_put(x);
82
83 return 0;
84 }
85
ipcomp6_tunnel_create(struct xfrm_state * x)86 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
87 {
88 struct net *net = xs_net(x);
89 struct xfrm_state *t = NULL;
90
91 t = xfrm_state_alloc(net);
92 if (!t)
93 goto out;
94
95 t->id.proto = IPPROTO_IPV6;
96 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr);
97 if (!t->id.spi)
98 goto error;
99
100 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
101 memcpy(&t->sel, &x->sel, sizeof(t->sel));
102 t->props.family = AF_INET6;
103 t->props.mode = x->props.mode;
104 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
105 memcpy(&t->mark, &x->mark, sizeof(t->mark));
106
107 if (xfrm_init_state(t))
108 goto error;
109
110 atomic_set(&t->tunnel_users, 1);
111
112 out:
113 return t;
114
115 error:
116 t->km.state = XFRM_STATE_DEAD;
117 xfrm_state_put(t);
118 t = NULL;
119 goto out;
120 }
121
ipcomp6_tunnel_attach(struct xfrm_state * x)122 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
123 {
124 struct net *net = xs_net(x);
125 int err = 0;
126 struct xfrm_state *t = NULL;
127 __be32 spi;
128 u32 mark = x->mark.m & x->mark.v;
129
130 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
131 if (spi)
132 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr,
133 spi, IPPROTO_IPV6, AF_INET6);
134 if (!t) {
135 t = ipcomp6_tunnel_create(x);
136 if (!t) {
137 err = -EINVAL;
138 goto out;
139 }
140 xfrm_state_insert(t);
141 xfrm_state_hold(t);
142 }
143 x->tunnel = t;
144 atomic_inc(&t->tunnel_users);
145
146 out:
147 return err;
148 }
149
ipcomp6_init_state(struct xfrm_state * x)150 static int ipcomp6_init_state(struct xfrm_state *x)
151 {
152 int err = -EINVAL;
153
154 x->props.header_len = 0;
155 switch (x->props.mode) {
156 case XFRM_MODE_TRANSPORT:
157 break;
158 case XFRM_MODE_TUNNEL:
159 x->props.header_len += sizeof(struct ipv6hdr);
160 break;
161 default:
162 goto out;
163 }
164
165 err = ipcomp_init_state(x);
166 if (err)
167 goto out;
168
169 if (x->props.mode == XFRM_MODE_TUNNEL) {
170 err = ipcomp6_tunnel_attach(x);
171 if (err)
172 goto out;
173 }
174
175 err = 0;
176 out:
177 return err;
178 }
179
ipcomp6_rcv_cb(struct sk_buff * skb,int err)180 static int ipcomp6_rcv_cb(struct sk_buff *skb, int err)
181 {
182 return 0;
183 }
184
185 static const struct xfrm_type ipcomp6_type = {
186 .description = "IPCOMP6",
187 .owner = THIS_MODULE,
188 .proto = IPPROTO_COMP,
189 .init_state = ipcomp6_init_state,
190 .destructor = ipcomp_destroy,
191 .input = ipcomp_input,
192 .output = ipcomp_output,
193 .hdr_offset = xfrm6_find_1stfragopt,
194 };
195
196 static struct xfrm6_protocol ipcomp6_protocol = {
197 .handler = xfrm6_rcv,
198 .cb_handler = ipcomp6_rcv_cb,
199 .err_handler = ipcomp6_err,
200 .priority = 0,
201 };
202
ipcomp6_init(void)203 static int __init ipcomp6_init(void)
204 {
205 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
206 pr_info("%s: can't add xfrm type\n", __func__);
207 return -EAGAIN;
208 }
209 if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
210 pr_info("%s: can't add protocol\n", __func__);
211 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
212 return -EAGAIN;
213 }
214 return 0;
215 }
216
ipcomp6_fini(void)217 static void __exit ipcomp6_fini(void)
218 {
219 if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0)
220 pr_info("%s: can't remove protocol\n", __func__);
221 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
222 pr_info("%s: can't remove xfrm type\n", __func__);
223 }
224
225 module_init(ipcomp6_init);
226 module_exit(ipcomp6_fini);
227 MODULE_LICENSE("GPL");
228 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
229 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
230
231 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
232
