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16#include <linux/module.h>
17#include <linux/err.h>
18#include <linux/rtnetlink.h>
19#include <net/ip.h>
20#include <net/xfrm.h>
21#include <net/icmp.h>
22#include <net/ipcomp.h>
23#include <net/protocol.h>
24#include <net/sock.h>
25
26static void ipcomp4_err(struct sk_buff *skb, u32 info)
27{
28 struct net *net = dev_net(skb->dev);
29 __be32 spi;
30 const struct iphdr *iph = (const struct iphdr *)skb->data;
31 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
32 struct xfrm_state *x;
33
34 switch (icmp_hdr(skb)->type) {
35 case ICMP_DEST_UNREACH:
36 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
37 return;
38 case ICMP_REDIRECT:
39 break;
40 default:
41 return;
42 }
43
44 spi = htonl(ntohs(ipch->cpi));
45 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
46 spi, IPPROTO_COMP, AF_INET);
47 if (!x)
48 return;
49
50 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
51 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
52 else
53 ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
54 xfrm_state_put(x);
55}
56
57
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 == NULL)
65 goto out;
66
67 t->id.proto = IPPROTO_IPIP;
68 t->id.spi = x->props.saddr.a4;
69 t->id.daddr.a4 = x->id.daddr.a4;
70 memcpy(&t->sel, &x->sel, sizeof(t->sel));
71 t->props.family = AF_INET;
72 t->props.mode = x->props.mode;
73 t->props.saddr.a4 = x->props.saddr.a4;
74 t->props.flags = x->props.flags;
75 t->props.extra_flags = x->props.extra_flags;
76 memcpy(&t->mark, &x->mark, sizeof(t->mark));
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 const struct xfrm_type ipcomp_type = {
151 .description = "IPCOMP4",
152 .owner = THIS_MODULE,
153 .proto = IPPROTO_COMP,
154 .init_state = ipcomp4_init_state,
155 .destructor = ipcomp_destroy,
156 .input = ipcomp_input,
157 .output = ipcomp_output
158};
159
160static const struct net_protocol ipcomp4_protocol = {
161 .handler = xfrm4_rcv,
162 .err_handler = ipcomp4_err,
163 .no_policy = 1,
164 .netns_ok = 1,
165};
166
167static int __init ipcomp4_init(void)
168{
169 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
170 pr_info("%s: can't add xfrm type\n", __func__);
171 return -EAGAIN;
172 }
173 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
174 pr_info("%s: can't add protocol\n", __func__);
175 xfrm_unregister_type(&ipcomp_type, AF_INET);
176 return -EAGAIN;
177 }
178 return 0;
179}
180
181static void __exit ipcomp4_fini(void)
182{
183 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
184 pr_info("%s: can't remove protocol\n", __func__);
185 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
186 pr_info("%s: can't remove xfrm type\n", __func__);
187}
188
189module_init(ipcomp4_init);
190module_exit(ipcomp4_fini);
191
192MODULE_LICENSE("GPL");
193MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
194MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
195
196MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
197
