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(dev: 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, mark: skb->mark, daddr: (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, oif: skb->dev->ifindex, mark: 0,
66 uid: sock_net_uid(net, NULL));
67 else
68 ip6_update_pmtu(skb, net, mtu: info, oif: 0, mark: 0, uid: sock_net_uid(net, NULL));
69 xfrm_state_put(x);
70
71 return 0;
72}
73
74static 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, saddr: (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 t->if_id = x->if_id;
95
96 if (xfrm_init_state(x: t))
97 goto error;
98
99 atomic_set(v: &t->tunnel_users, i: 1);
100
101out:
102 return t;
103
104error:
105 t->km.state = XFRM_STATE_DEAD;
106 xfrm_state_put(x: t);
107 t = NULL;
108 goto out;
109}
110
111static int ipcomp6_tunnel_attach(struct xfrm_state *x)
112{
113 struct net *net = xs_net(x);
114 int err = 0;
115 struct xfrm_state *t = NULL;
116 __be32 spi;
117 u32 mark = x->mark.m & x->mark.v;
118
119 spi = xfrm6_tunnel_spi_lookup(net, saddr: (xfrm_address_t *)&x->props.saddr);
120 if (spi)
121 t = xfrm_state_lookup(net, mark, daddr: (xfrm_address_t *)&x->id.daddr,
122 spi, IPPROTO_IPV6, AF_INET6);
123 if (!t) {
124 t = ipcomp6_tunnel_create(x);
125 if (!t) {
126 err = -EINVAL;
127 goto out;
128 }
129 xfrm_state_insert(x: t);
130 xfrm_state_hold(x: t);
131 }
132 x->tunnel = t;
133 atomic_inc(v: &t->tunnel_users);
134
135out:
136 return err;
137}
138
139static int ipcomp6_init_state(struct xfrm_state *x,
140 struct netlink_ext_ack *extack)
141{
142 int err = -EINVAL;
143
144 x->props.header_len = 0;
145 switch (x->props.mode) {
146 case XFRM_MODE_TRANSPORT:
147 break;
148 case XFRM_MODE_TUNNEL:
149 x->props.header_len += sizeof(struct ipv6hdr);
150 break;
151 default:
152 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
153 goto out;
154 }
155
156 err = ipcomp_init_state(x, extack);
157 if (err)
158 goto out;
159
160 if (x->props.mode == XFRM_MODE_TUNNEL) {
161 err = ipcomp6_tunnel_attach(x);
162 if (err) {
163 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
164 goto out;
165 }
166 }
167
168 err = 0;
169out:
170 return err;
171}
172
173static int ipcomp6_rcv_cb(struct sk_buff *skb, int err)
174{
175 return 0;
176}
177
178static const struct xfrm_type ipcomp6_type = {
179 .owner = THIS_MODULE,
180 .proto = IPPROTO_COMP,
181 .init_state = ipcomp6_init_state,
182 .destructor = ipcomp_destroy,
183 .input = ipcomp_input,
184 .output = ipcomp_output,
185};
186
187static struct xfrm6_protocol ipcomp6_protocol = {
188 .handler = xfrm6_rcv,
189 .input_handler = xfrm_input,
190 .cb_handler = ipcomp6_rcv_cb,
191 .err_handler = ipcomp6_err,
192 .priority = 0,
193};
194
195static int __init ipcomp6_init(void)
196{
197 if (xfrm_register_type(type: &ipcomp6_type, AF_INET6) < 0) {
198 pr_info("%s: can't add xfrm type\n", __func__);
199 return -EAGAIN;
200 }
201 if (xfrm6_protocol_register(handler: &ipcomp6_protocol, IPPROTO_COMP) < 0) {
202 pr_info("%s: can't add protocol\n", __func__);
203 xfrm_unregister_type(type: &ipcomp6_type, AF_INET6);
204 return -EAGAIN;
205 }
206 return 0;
207}
208
209static void __exit ipcomp6_fini(void)
210{
211 if (xfrm6_protocol_deregister(handler: &ipcomp6_protocol, IPPROTO_COMP) < 0)
212 pr_info("%s: can't remove protocol\n", __func__);
213 xfrm_unregister_type(type: &ipcomp6_type, AF_INET6);
214}
215
216module_init(ipcomp6_init);
217module_exit(ipcomp6_fini);
218MODULE_LICENSE("GPL");
219MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
220MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
221
222MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
223

source code of linux/net/ipv6/ipcomp6.c