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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 __be32 spi;
29 struct iphdr *iph = (struct iphdr *)skb->data;
30 struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
31 struct xfrm_state *x;
32
33 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
34 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
35 return;
36
37 spi = htonl(ntohs(ipch->cpi));
38 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
39 spi, IPPROTO_COMP, AF_INET);
40 if (!x)
41 return;
42 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIPQUAD_FMT "\n",
43 spi, NIPQUAD(iph->daddr));
44 xfrm_state_put(x);
45}
46
47
48static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
49{
50 struct xfrm_state *t;
51
52 t = xfrm_state_alloc();
53 if (t == NULL)
54 goto out;
55
56 t->id.proto = IPPROTO_IPIP;
57 t->id.spi = x->props.saddr.a4;
58 t->id.daddr.a4 = x->id.daddr.a4;
59 memcpy(&t->sel, &x->sel, sizeof(t->sel));
60 t->props.family = AF_INET;
61 t->props.mode = x->props.mode;
62 t->props.saddr.a4 = x->props.saddr.a4;
63 t->props.flags = x->props.flags;
64
65 if (xfrm_init_state(t))
66 goto error;
67
68 atomic_set(&t->tunnel_users, 1);
69out:
70 return t;
71
72error:
73 t->km.state = XFRM_STATE_DEAD;
74 xfrm_state_put(t);
75 t = NULL;
76 goto out;
77}
78
79
80
81
82
83static int ipcomp_tunnel_attach(struct xfrm_state *x)
84{
85 int err = 0;
86 struct xfrm_state *t;
87
88 t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
89 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
90 if (!t) {
91 t = ipcomp_tunnel_create(x);
92 if (!t) {
93 err = -EINVAL;
94 goto out;
95 }
96 xfrm_state_insert(t);
97 xfrm_state_hold(t);
98 }
99 x->tunnel = t;
100 atomic_inc(&t->tunnel_users);
101out:
102 return err;
103}
104
105static int ipcomp4_init_state(struct xfrm_state *x)
106{
107 int err = -EINVAL;
108
109 x->props.header_len = 0;
110 switch (x->props.mode) {
111 case XFRM_MODE_TRANSPORT:
112 break;
113 case XFRM_MODE_TUNNEL:
114 x->props.header_len += sizeof(struct iphdr);
115 break;
116 default:
117 goto out;
118 }
119
120 err = ipcomp_init_state(x);
121 if (err)
122 goto out;
123
124 if (x->props.mode == XFRM_MODE_TUNNEL) {
125 err = ipcomp_tunnel_attach(x);
126 if (err)
127 goto error_tunnel;
128 }
129
130 err = 0;
131out:
132 return err;
133
134error_tunnel:
135 ipcomp_destroy(x);
136 goto out;
137}
138
139static const struct xfrm_type ipcomp_type = {
140 .description = "IPCOMP4",
141 .owner = THIS_MODULE,
142 .proto = IPPROTO_COMP,
143 .init_state = ipcomp4_init_state,
144 .destructor = ipcomp_destroy,
145 .input = ipcomp_input,
146 .output = ipcomp_output
147};
148
149static struct net_protocol ipcomp4_protocol = {
150 .handler = xfrm4_rcv,
151 .err_handler = ipcomp4_err,
152 .no_policy = 1,
153};
154
155static int __init ipcomp4_init(void)
156{
157 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
158 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
159 return -EAGAIN;
160 }
161 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
162 printk(KERN_INFO "ipcomp init: can't add protocol\n");
163 xfrm_unregister_type(&ipcomp_type, AF_INET);
164 return -EAGAIN;
165 }
166 return 0;
167}
168
169static void __exit ipcomp4_fini(void)
170{
171 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
172 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
173 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
174 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
175}
176
177module_init(ipcomp4_init);
178module_exit(ipcomp4_fini);
179
180MODULE_LICENSE("GPL");
181MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
182MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
183
184MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
185
