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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 | |
4 | * | |
5 | * Copyright (C)2003 USAGI/WIDE Project | |
6 | * | |
7 | * Author Mitsuru KANDA <mk@linux-ipv6.org> | |
8 | */ | |
9 | /* | |
10 | * [Memo] | |
11 | * | |
12 | * Outbound: | |
13 | * The compression of IP datagram MUST be done before AH/ESP processing, | |
14 | * fragmentation, and the addition of Hop-by-Hop/Routing header. | |
15 | * | |
16 | * Inbound: | |
17 | * The decompression of IP datagram MUST be done after the reassembly, | |
18 | * AH/ESP processing. | |
19 | */ | |
20 | ||
21 | #define pr_fmt(fmt) "IPv6: " fmt | |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <net/ip.h> | |
25 | #include <net/xfrm.h> | |
26 | #include <net/ipcomp.h> | |
27 | #include <linux/crypto.h> | |
28 | #include <linux/err.h> | |
29 | #include <linux/pfkeyv2.h> | |
30 | #include <linux/random.h> | |
31 | #include <linux/percpu.h> | |
32 | #include <linux/smp.h> | |
33 | #include <linux/list.h> | |
34 | #include <linux/vmalloc.h> | |
35 | #include <linux/rtnetlink.h> | |
36 | #include <net/ip6_route.h> | |
37 | #include <net/icmp.h> | |
38 | #include <net/ipv6.h> | |
39 | #include <net/protocol.h> | |
40 | #include <linux/ipv6.h> | |
41 | #include <linux/icmpv6.h> | |
42 | #include <linux/mutex.h> | |
43 | ||
44 | static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
45 | u8 type, u8 code, int offset, __be32 info) | |
46 | { | |
47 | struct net *net = dev_net(skb->dev); | |
48 | __be32 spi; | |
49 | const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; | |
50 | struct ip_comp_hdr *ipcomph = | |
51 | (struct ip_comp_hdr *)(skb->data + offset); | |
52 | struct xfrm_state *x; | |
53 | ||
54 | if (type != ICMPV6_PKT_TOOBIG && | |
55 | type != NDISC_REDIRECT) | |
56 | return 0; | |
57 | ||
58 | spi = htonl(ntohs(ipcomph->cpi)); | |
59 | x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, | |
60 | spi, IPPROTO_COMP, AF_INET6); | |
61 | if (!x) | |
62 | return 0; | |
63 | ||
64 | if (type == NDISC_REDIRECT) | |
65 | ip6_redirect(skb, net, skb->dev->ifindex, 0, | |
66 | sock_net_uid(net, NULL)); | |
67 | else | |
68 | ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); | |
69 | xfrm_state_put(x); | |
70 | ||
71 | return 0; | |
72 | } | |
73 | ||
74 | static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) | |
75 | { | |
76 | struct net *net = xs_net(x); | |
77 | struct xfrm_state *t = NULL; | |
78 | ||
79 | t = xfrm_state_alloc(net); | |
80 | if (!t) | |
81 | goto out; | |
82 | ||
83 | t->id.proto = IPPROTO_IPV6; | |
84 | t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); | |
85 | if (!t->id.spi) | |
86 | goto error; | |
87 | ||
88 | memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); | |
89 | memcpy(&t->sel, &x->sel, sizeof(t->sel)); | |
90 | t->props.family = AF_INET6; | |
91 | t->props.mode = x->props.mode; | |
92 | memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); | |
93 | memcpy(&t->mark, &x->mark, sizeof(t->mark)); | |
94 | ||
95 | if (xfrm_init_state(t)) | |
96 | goto error; | |
97 | ||
98 | atomic_set(&t->tunnel_users, 1); | |
99 | ||
100 | out: | |
101 | return t; | |
102 | ||
103 | error: | |
104 | t->km.state = XFRM_STATE_DEAD; | |
105 | xfrm_state_put(t); | |
106 | t = NULL; | |
107 | goto out; | |
108 | } | |
109 | ||
110 | static int ipcomp6_tunnel_attach(struct xfrm_state *x) | |
111 | { | |
112 | struct net *net = xs_net(x); | |
113 | int err = 0; | |
114 | struct xfrm_state *t = NULL; | |
115 | __be32 spi; | |
116 | u32 mark = x->mark.m & x->mark.v; | |
117 | ||
118 | spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); | |
119 | if (spi) | |
120 | t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, | |
121 | spi, IPPROTO_IPV6, AF_INET6); | |
122 | if (!t) { | |
123 | t = ipcomp6_tunnel_create(x); | |
124 | if (!t) { | |
125 | err = -EINVAL; | |
126 | goto out; | |
127 | } | |
128 | xfrm_state_insert(t); | |
129 | xfrm_state_hold(t); | |
130 | } | |
131 | x->tunnel = t; | |
132 | atomic_inc(&t->tunnel_users); | |
133 | ||
134 | out: | |
135 | return err; | |
136 | } | |
137 | ||
138 | static int ipcomp6_init_state(struct xfrm_state *x) | |
139 | { | |
140 | int err = -EINVAL; | |
141 | ||
142 | x->props.header_len = 0; | |
143 | switch (x->props.mode) { | |
144 | case XFRM_MODE_TRANSPORT: | |
145 | break; | |
146 | case XFRM_MODE_TUNNEL: | |
147 | x->props.header_len += sizeof(struct ipv6hdr); | |
148 | break; | |
149 | default: | |
150 | goto out; | |
151 | } | |
152 | ||
153 | err = ipcomp_init_state(x); | |
154 | if (err) | |
155 | goto out; | |
156 | ||
157 | if (x->props.mode == XFRM_MODE_TUNNEL) { | |
158 | err = ipcomp6_tunnel_attach(x); | |
159 | if (err) | |
160 | goto out; | |
161 | } | |
162 | ||
163 | err = 0; | |
164 | out: | |
165 | return err; | |
166 | } | |
167 | ||
168 | static int ipcomp6_rcv_cb(struct sk_buff *skb, int err) | |
169 | { | |
170 | return 0; | |
171 | } | |
172 | ||
173 | static const struct xfrm_type ipcomp6_type = { | |
174 | .description = "IPCOMP6", | |
175 | .owner = THIS_MODULE, | |
176 | .proto = IPPROTO_COMP, | |
177 | .init_state = ipcomp6_init_state, | |
178 | .destructor = ipcomp_destroy, | |
179 | .input = ipcomp_input, | |
180 | .output = ipcomp_output, | |
181 | .hdr_offset = xfrm6_find_1stfragopt, | |
182 | }; | |
183 | ||
184 | static struct xfrm6_protocol ipcomp6_protocol = { | |
185 | .handler = xfrm6_rcv, | |
186 | .cb_handler = ipcomp6_rcv_cb, | |
187 | .err_handler = ipcomp6_err, | |
188 | .priority = 0, | |
189 | }; | |
190 | ||
191 | static int __init ipcomp6_init(void) | |
192 | { | |
193 | if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { | |
194 | pr_info("%s: can't add xfrm type\n", __func__); | |
195 | return -EAGAIN; | |
196 | } | |
197 | if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) { | |
198 | pr_info("%s: can't add protocol\n", __func__); | |
199 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
200 | return -EAGAIN; | |
201 | } | |
202 | return 0; | |
203 | } | |
204 | ||
205 | static void __exit ipcomp6_fini(void) | |
206 | { | |
207 | if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0) | |
208 | pr_info("%s: can't remove protocol\n", __func__); | |
209 | xfrm_unregister_type(&ipcomp6_type, AF_INET6); | |
210 | } | |
211 | ||
212 | module_init(ipcomp6_init); | |
213 | module_exit(ipcomp6_fini); | |
214 | MODULE_LICENSE("GPL"); | |
215 | MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); | |
216 | MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); | |
217 | ||
218 | MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); |