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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
57static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
58{
59 struct net *net = xs_net(x);
60 struct xfrm_state *t;
61
62 t = xfrm_state_alloc(net);
63 if (!t)
64 goto out;
65
66 t->id.proto = IPPROTO_IPIP;
67 t->id.spi = x->props.saddr.a4;
68 t->id.daddr.a4 = x->id.daddr.a4;
69 memcpy(&t->sel, &x->sel, sizeof(t->sel));
70 t->props.family = AF_INET;
71 t->props.mode = x->props.mode;
72 t->props.saddr.a4 = x->props.saddr.a4;
73 t->props.flags = x->props.flags;
74 t->props.extra_flags = x->props.extra_flags;
75 memcpy(&t->mark, &x->mark, sizeof(t->mark));
76 t->if_id = x->if_id;
77
78 if (xfrm_init_state(t))
79 goto error;
80
81 atomic_set(&t->tunnel_users, 1);
82out:
83 return t;
84
85error:
86 t->km.state = XFRM_STATE_DEAD;
87 xfrm_state_put(t);
88 t = NULL;
89 goto out;
90}
91
92
93
94
95
96static int ipcomp_tunnel_attach(struct xfrm_state *x)
97{
98 struct net *net = xs_net(x);
99 int err = 0;
100 struct xfrm_state *t;
101 u32 mark = x->mark.v & x->mark.m;
102
103 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
104 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
105 if (!t) {
106 t = ipcomp_tunnel_create(x);
107 if (!t) {
108 err = -EINVAL;
109 goto out;
110 }
111 xfrm_state_insert(t);
112 xfrm_state_hold(t);
113 }
114 x->tunnel = t;
115 atomic_inc(&t->tunnel_users);
116out:
117 return err;
118}
119
120static int ipcomp4_init_state(struct xfrm_state *x)
121{
122 int err = -EINVAL;
123
124 x->props.header_len = 0;
125 switch (x->props.mode) {
126 case XFRM_MODE_TRANSPORT:
127 break;
128 case XFRM_MODE_TUNNEL:
129 x->props.header_len += sizeof(struct iphdr);
130 break;
131 default:
132 goto out;
133 }
134
135 err = ipcomp_init_state(x);
136 if (err)
137 goto out;
138
139 if (x->props.mode == XFRM_MODE_TUNNEL) {
140 err = ipcomp_tunnel_attach(x);
141 if (err)
142 goto out;
143 }
144
145 err = 0;
146out:
147 return err;
148}
149
150static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
151{
152 return 0;
153}
154
155static const struct xfrm_type ipcomp_type = {
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
