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linux
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
44static 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
74static struct lock_class_key xfrm_state_lock_key;
75static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
76{
77 struct net *net = xs_net(x);
78 struct xfrm_state *t = NULL;
79
80 t = xfrm_state_alloc(net);
81 if (!t)
82 goto out;
83 lockdep_set_class(&t->lock, &xfrm_state_lock_key);
84
85 t->id.proto = IPPROTO_IPV6;
86 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr);
87 if (!t->id.spi)
88 goto error;
89
90 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
91 memcpy(&t->sel, &x->sel, sizeof(t->sel));
92 t->props.family = AF_INET6;
93 t->props.mode = x->props.mode;
94 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
95 memcpy(&t->mark, &x->mark, sizeof(t->mark));
96 t->if_id = x->if_id;
97
98 if (xfrm_init_state(t))
99 goto error;
100
101 atomic_set(&t->tunnel_users, 1);
102
103out:
104 return t;
105
106error:
107 t->km.state = XFRM_STATE_DEAD;
108 xfrm_state_put(t);
109 t = NULL;
110 goto out;
111}
112
113static int ipcomp6_tunnel_attach(struct xfrm_state *x)
114{
115 struct net *net = xs_net(x);
116 int err = 0;
117 struct xfrm_state *t = NULL;
118 __be32 spi;
119 u32 mark = x->mark.m & x->mark.v;
120
121 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
122 if (spi)
123 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr,
124 spi, IPPROTO_IPV6, AF_INET6);
125 if (!t) {
126 t = ipcomp6_tunnel_create(x);
127 if (!t) {
128 err = -EINVAL;
129 goto out;
130 }
131 xfrm_state_insert(t);
132 xfrm_state_hold(t);
133 }
134 x->tunnel = t;
135 atomic_inc(&t->tunnel_users);
136
137out:
138 return err;
139}
140
141static int ipcomp6_init_state(struct xfrm_state *x,
142 struct netlink_ext_ack *extack)
143{
144 int err = -EINVAL;
145
146 x->props.header_len = 0;
147 switch (x->props.mode) {
148 case XFRM_MODE_TRANSPORT:
149 break;
150 case XFRM_MODE_TUNNEL:
151 x->props.header_len += sizeof(struct ipv6hdr);
152 break;
153 default:
154 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
155 goto out;
156 }
157
158 err = ipcomp_init_state(x, extack);
159 if (err)
160 goto out;
161
162 if (x->props.mode == XFRM_MODE_TUNNEL) {
163 err = ipcomp6_tunnel_attach(x);
164 if (err) {
165 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
166 goto out;
167 }
168 }
169
170 err = 0;
171out:
172 return err;
173}
174
175static int ipcomp6_rcv_cb(struct sk_buff *skb, int err)
176{
177 return 0;
178}
179
180static const struct xfrm_type ipcomp6_type = {
181 .owner = THIS_MODULE,
182 .proto = IPPROTO_COMP,
183 .init_state = ipcomp6_init_state,
184 .destructor = ipcomp_destroy,
185 .input = ipcomp_input,
186 .output = ipcomp_output,
187};
188
189static struct xfrm6_protocol ipcomp6_protocol = {
190 .handler = xfrm6_rcv,
191 .input_handler = xfrm_input,
192 .cb_handler = ipcomp6_rcv_cb,
193 .err_handler = ipcomp6_err,
194 .priority = 0,
195};
196
197static int __init ipcomp6_init(void)
198{
199 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
200 pr_info("%s: can't add xfrm type\n", __func__);
201 return -EAGAIN;
202 }
203 if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
204 pr_info("%s: can't add protocol\n", __func__);
205 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
206 return -EAGAIN;
207 }
208 return 0;
209}
210
211static void __exit ipcomp6_fini(void)
212{
213 if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0)
214 pr_info("%s: can't remove protocol\n", __func__);
215 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
216}
217
218module_init(ipcomp6_init);
219module_exit(ipcomp6_fini);
220MODULE_LICENSE("GPL");
221MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
222MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
223
224MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);