1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IP Payload Compression Protocol (IPComp) - RFC3173.
*
* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
*
* Todo:
* - Tunable compression parameters.
* - Compression stats.
* - Adaptive compression.
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/rtnetlink.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/ipcomp.h>
#include <net/protocol.h>
#include <net/sock.h>
static int ipcomp4_err(struct sk_buff *skb, u32 info)
{
struct net *net = dev_net(skb->dev);
__be32 spi;
const struct iphdr *iph = (const struct iphdr *)skb->data;
struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
struct xfrm_state *x;
switch (icmp_hdr(skb)->type) {
case ICMP_DEST_UNREACH:
if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
return 0;
case ICMP_REDIRECT:
break;
default:
return 0;
}
spi = htonl(ntohs(ipch->cpi));
x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
spi, IPPROTO_COMP, AF_INET);
if (!x)
return 0;
if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
else
ipv4_redirect(skb, net, 0, IPPROTO_COMP);
xfrm_state_put(x);
return 0;
}
/* We always hold one tunnel user reference to indicate a tunnel */
static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
{
struct net *net = xs_net(x);
struct xfrm_state *t;
t = xfrm_state_alloc(net);
if (!t)
goto out;
t->id.proto = IPPROTO_IPIP;
t->id.spi = x->props.saddr.a4;
t->id.daddr.a4 = x->id.daddr.a4;
memcpy(&t->sel, &x->sel, sizeof(t->sel));
t->props.family = AF_INET;
t->props.mode = x->props.mode;
t->props.saddr.a4 = x->props.saddr.a4;
t->props.flags = x->props.flags;
t->props.extra_flags = x->props.extra_flags;
memcpy(&t->mark, &x->mark, sizeof(t->mark));
if (xfrm_init_state(t))
goto error;
atomic_set(&t->tunnel_users, 1);
out:
return t;
error:
t->km.state = XFRM_STATE_DEAD;
xfrm_state_put(t);
t = NULL;
goto out;
}
/*
* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
* always incremented on success.
*/
static int ipcomp_tunnel_attach(struct xfrm_state *x)
{
struct net *net = xs_net(x);
int err = 0;
struct xfrm_state *t;
u32 mark = x->mark.v & x->mark.m;
t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
if (!t) {
t = ipcomp_tunnel_create(x);
if (!t) {
err = -EINVAL;
goto out;
}
xfrm_state_insert(t);
xfrm_state_hold(t);
}
x->tunnel = t;
atomic_inc(&t->tunnel_users);
out:
return err;
}
static int ipcomp4_init_state(struct xfrm_state *x)
{
int err = -EINVAL;
x->props.header_len = 0;
switch (x->props.mode) {
case XFRM_MODE_TRANSPORT:
break;
case XFRM_MODE_TUNNEL:
x->props.header_len += sizeof(struct iphdr);
break;
default:
goto out;
}
err = ipcomp_init_state(x);
if (err)
goto out;
if (x->props.mode == XFRM_MODE_TUNNEL) {
err = ipcomp_tunnel_attach(x);
if (err)
goto out;
}
err = 0;
out:
return err;
}
static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
{
return 0;
}
static const struct xfrm_type ipcomp_type = {
.description = "IPCOMP4",
.owner = THIS_MODULE,
.proto = IPPROTO_COMP,
.init_state = ipcomp4_init_state,
.destructor = ipcomp_destroy,
.input = ipcomp_input,
.output = ipcomp_output
};
static struct xfrm4_protocol ipcomp4_protocol = {
.handler = xfrm4_rcv,
.input_handler = xfrm_input,
.cb_handler = ipcomp4_rcv_cb,
.err_handler = ipcomp4_err,
.priority = 0,
};
static int __init ipcomp4_init(void)
{
if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
pr_info("%s: can't add xfrm type\n", __func__);
return -EAGAIN;
}
if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
pr_info("%s: can't add protocol\n", __func__);
xfrm_unregister_type(&ipcomp_type, AF_INET);
return -EAGAIN;
}
return 0;
}
static void __exit ipcomp4_fini(void)
{
if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
pr_info("%s: can't remove protocol\n", __func__);
xfrm_unregister_type(&ipcomp_type, AF_INET);
}
module_init(ipcomp4_init);
module_exit(ipcomp4_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
|
