1
2
3
4
5
6
7
8
9
10
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 case ICMP_REDIRECT:
35 break;
36 default:
37 return 0;
38 }
39
40 spi = htonl(ntohs(ipch->cpi));
41 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
42 spi, IPPROTO_COMP, AF_INET);
43 if (!x)
44 return 0;
45
46 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
47 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
48 else
49 ipv4_redirect(skb, net, 0, IPPROTO_COMP);
50 xfrm_state_put(x);
51
52 return 0;
53}
54
55
56static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
57{
58 struct net *net = xs_net(x);
59 struct xfrm_state *t;
60
61 t = xfrm_state_alloc(net);
62 if (!t)
63 goto out;
64
65 t->id.proto = IPPROTO_IPIP;
66 t->id.spi = x->props.saddr.a4;
67 t->id.daddr.a4 = x->id.daddr.a4;
68 memcpy(&t->sel, &x->sel, sizeof(t->sel));
69 t->props.family = AF_INET;
70 t->props.mode = x->props.mode;
71 t->props.saddr.a4 = x->props.saddr.a4;
72 t->props.flags = x->props.flags;
73 t->props.extra_flags = x->props.extra_flags;
74 memcpy(&t->mark, &x->mark, sizeof(t->mark));
75 t->if_id = x->if_id;
76
77 if (xfrm_init_state(t))
78 goto error;
79
80 atomic_set(&t->tunnel_users, 1);
81out:
82 return t;
83
84error:
85 t->km.state = XFRM_STATE_DEAD;
86 xfrm_state_put(t);
87 t = NULL;
88 goto out;
89}
90
91
92
93
94
95static int ipcomp_tunnel_attach(struct xfrm_state *x)
96{
97 struct net *net = xs_net(x);
98 int err = 0;
99 struct xfrm_state *t;
100 u32 mark = x->mark.v & x->mark.m;
101
102 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
103 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
104 if (!t) {
105 t = ipcomp_tunnel_create(x);
106 if (!t) {
107 err = -EINVAL;
108 goto out;
109 }
110 xfrm_state_insert(t);
111 xfrm_state_hold(t);
112 }
113 x->tunnel = t;
114 atomic_inc(&t->tunnel_users);
115out:
116 return err;
117}
118
119static int ipcomp4_init_state(struct xfrm_state *x)
120{
121 int err = -EINVAL;
122
123 x->props.header_len = 0;
124 switch (x->props.mode) {
125 case XFRM_MODE_TRANSPORT:
126 break;
127 case XFRM_MODE_TUNNEL:
128 x->props.header_len += sizeof(struct iphdr);
129 break;
130 default:
131 goto out;
132 }
133
134 err = ipcomp_init_state(x);
135 if (err)
136 goto out;
137
138 if (x->props.mode == XFRM_MODE_TUNNEL) {
139 err = ipcomp_tunnel_attach(x);
140 if (err)
141 goto out;
142 }
143
144 err = 0;
145out:
146 return err;
147}
148
149static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
150{
151 return 0;
152}
153
154static const struct xfrm_type ipcomp_type = {
155 .description = "IPCOMP4",
156 .owner = THIS_MODULE,
157 .proto = IPPROTO_COMP,
158 .init_state = ipcomp4_init_state,
159 .destructor = ipcomp_destroy,
160 .input = ipcomp_input,
161 .output = ipcomp_output
162};
163
164static struct xfrm4_protocol ipcomp4_protocol = {
165 .handler = xfrm4_rcv,
166 .input_handler = xfrm_input,
167 .cb_handler = ipcomp4_rcv_cb,
168 .err_handler = ipcomp4_err,
169 .priority = 0,
170};
171
172static int __init ipcomp4_init(void)
173{
174 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
175 pr_info("%s: can't add xfrm type\n", __func__);
176 return -EAGAIN;
177 }
178 if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
179 pr_info("%s: can't add protocol\n", __func__);
180 xfrm_unregister_type(&ipcomp_type, AF_INET);
181 return -EAGAIN;
182 }
183 return 0;
184}
185
186static void __exit ipcomp4_fini(void)
187{
188 if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
189 pr_info("%s: can't remove protocol\n", __func__);
190 xfrm_unregister_type(&ipcomp_type, AF_INET);
191}
192
193module_init(ipcomp4_init);
194module_exit(ipcomp4_fini);
195
196MODULE_LICENSE("GPL");
197MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
198MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
199
200MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
201
