Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IP Payload Compression Protocol (IPComp) - RFC3173.
4 *
5 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
6 *
7 * Todo:
8 * - Tunable compression parameters.
9 * - Compression stats.
10 * - Adaptive compression.
11 */
12#include <linux/module.h>
13#include <linux/err.h>
14#include <linux/rtnetlink.h>
15#include <net/ip.h>
16#include <net/xfrm.h>
17#include <net/icmp.h>
18#include <net/ipcomp.h>
19#include <net/protocol.h>
20#include <net/sock.h>
21
22static int ipcomp4_err(struct sk_buff *skb, u32 info)
23{
24 struct net *net = dev_net(skb->dev);
25 __be32 spi;
26 const struct iphdr *iph = (const struct iphdr *)skb->data;
27 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
28 struct xfrm_state *x;
29
30 switch (icmp_hdr(skb)->type) {
31 case ICMP_DEST_UNREACH:
32 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
33 return 0;
34 break;
35 case ICMP_REDIRECT:
36 break;
37 default:
38 return 0;
39 }
40
41 spi = htonl(ntohs(ipch->cpi));
42 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
43 spi, IPPROTO_COMP, AF_INET);
44 if (!x)
45 return 0;
46
47 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
48 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
49 else
50 ipv4_redirect(skb, net, 0, IPPROTO_COMP);
51 xfrm_state_put(x);
52
53 return 0;
54}
55
56/* We always hold one tunnel user reference to indicate a tunnel */
57static struct lock_class_key xfrm_state_lock_key;
58static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
59{
60 struct net *net = xs_net(x);
61 struct xfrm_state *t;
62
63 t = xfrm_state_alloc(net);
64 if (!t)
65 goto out;
66 lockdep_set_class(&t->lock, &xfrm_state_lock_key);
67
68 t->id.proto = IPPROTO_IPIP;
69 t->id.spi = x->props.saddr.a4;
70 t->id.daddr.a4 = x->id.daddr.a4;
71 memcpy(&t->sel, &x->sel, sizeof(t->sel));
72 t->props.family = AF_INET;
73 t->props.mode = x->props.mode;
74 t->props.saddr.a4 = x->props.saddr.a4;
75 t->props.flags = x->props.flags;
76 t->props.extra_flags = x->props.extra_flags;
77 memcpy(&t->mark, &x->mark, sizeof(t->mark));
78 t->if_id = x->if_id;
79
80 if (xfrm_init_state(t))
81 goto error;
82
83 atomic_set(&t->tunnel_users, 1);
84out:
85 return t;
86
87error:
88 t->km.state = XFRM_STATE_DEAD;
89 xfrm_state_put(t);
90 t = NULL;
91 goto out;
92}
93
94/*
95 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
96 * always incremented on success.
97 */
98static int ipcomp_tunnel_attach(struct xfrm_state *x)
99{
100 struct net *net = xs_net(x);
101 int err = 0;
102 struct xfrm_state *t;
103 u32 mark = x->mark.v & x->mark.m;
104
105 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
106 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
107 if (!t) {
108 t = ipcomp_tunnel_create(x);
109 if (!t) {
110 err = -EINVAL;
111 goto out;
112 }
113 xfrm_state_insert(t);
114 xfrm_state_hold(t);
115 }
116 x->tunnel = t;
117 atomic_inc(&t->tunnel_users);
118out:
119 return err;
120}
121
122static int ipcomp4_init_state(struct xfrm_state *x,
123 struct netlink_ext_ack *extack)
124{
125 int err = -EINVAL;
126
127 x->props.header_len = 0;
128 switch (x->props.mode) {
129 case XFRM_MODE_TRANSPORT:
130 break;
131 case XFRM_MODE_TUNNEL:
132 x->props.header_len += sizeof(struct iphdr);
133 break;
134 default:
135 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
136 goto out;
137 }
138
139 err = ipcomp_init_state(x, extack);
140 if (err)
141 goto out;
142
143 if (x->props.mode == XFRM_MODE_TUNNEL) {
144 err = ipcomp_tunnel_attach(x);
145 if (err) {
146 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
147 goto out;
148 }
149 }
150
151 err = 0;
152out:
153 return err;
154}
155
156static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
157{
158 return 0;
159}
160
161static const struct xfrm_type ipcomp_type = {
162 .owner = THIS_MODULE,
163 .proto = IPPROTO_COMP,
164 .init_state = ipcomp4_init_state,
165 .destructor = ipcomp_destroy,
166 .input = ipcomp_input,
167 .output = ipcomp_output
168};
169
170static struct xfrm4_protocol ipcomp4_protocol = {
171 .handler = xfrm4_rcv,
172 .input_handler = xfrm_input,
173 .cb_handler = ipcomp4_rcv_cb,
174 .err_handler = ipcomp4_err,
175 .priority = 0,
176};
177
178static int __init ipcomp4_init(void)
179{
180 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
181 pr_info("%s: can't add xfrm type\n", __func__);
182 return -EAGAIN;
183 }
184 if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
185 pr_info("%s: can't add protocol\n", __func__);
186 xfrm_unregister_type(&ipcomp_type, AF_INET);
187 return -EAGAIN;
188 }
189 return 0;
190}
191
192static void __exit ipcomp4_fini(void)
193{
194 if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
195 pr_info("%s: can't remove protocol\n", __func__);
196 xfrm_unregister_type(&ipcomp_type, AF_INET);
197}
198
199module_init(ipcomp4_init);
200module_exit(ipcomp4_fini);
201
202MODULE_LICENSE("GPL");
203MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
204MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
205
206MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);