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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 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
35 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
36 return;
37
38 spi = htonl(ntohs(ipch->cpi));
39 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
40 spi, IPPROTO_COMP, AF_INET);
41 if (!x)
42 return;
43 NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
44 spi, &iph->daddr);
45 xfrm_state_put(x);
46}
47
48
49static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
50{
51 struct net *net = xs_net(x);
52 struct xfrm_state *t;
53
54 t = xfrm_state_alloc(net);
55 if (t == NULL)
56 goto out;
57
58 t->id.proto = IPPROTO_IPIP;
59 t->id.spi = x->props.saddr.a4;
60 t->id.daddr.a4 = x->id.daddr.a4;
61 memcpy(&t->sel, &x->sel, sizeof(t->sel));
62 t->props.family = AF_INET;
63 t->props.mode = x->props.mode;
64 t->props.saddr.a4 = x->props.saddr.a4;
65 t->props.flags = x->props.flags;
66 memcpy(&t->mark, &x->mark, sizeof(t->mark));
67
68 if (xfrm_init_state(t))
69 goto error;
70
71 atomic_set(&t->tunnel_users, 1);
72out:
73 return t;
74
75error:
76 t->km.state = XFRM_STATE_DEAD;
77 xfrm_state_put(t);
78 t = NULL;
79 goto out;
80}
81
82
83
84
85
86static int ipcomp_tunnel_attach(struct xfrm_state *x)
87{
88 struct net *net = xs_net(x);
89 int err = 0;
90 struct xfrm_state *t;
91 u32 mark = x->mark.v & x->mark.m;
92
93 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
94 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
95 if (!t) {
96 t = ipcomp_tunnel_create(x);
97 if (!t) {
98 err = -EINVAL;
99 goto out;
100 }
101 xfrm_state_insert(t);
102 xfrm_state_hold(t);
103 }
104 x->tunnel = t;
105 atomic_inc(&t->tunnel_users);
106out:
107 return err;
108}
109
110static int ipcomp4_init_state(struct xfrm_state *x)
111{
112 int err = -EINVAL;
113
114 x->props.header_len = 0;
115 switch (x->props.mode) {
116 case XFRM_MODE_TRANSPORT:
117 break;
118 case XFRM_MODE_TUNNEL:
119 x->props.header_len += sizeof(struct iphdr);
120 break;
121 default:
122 goto out;
123 }
124
125 err = ipcomp_init_state(x);
126 if (err)
127 goto out;
128
129 if (x->props.mode == XFRM_MODE_TUNNEL) {
130 err = ipcomp_tunnel_attach(x);
131 if (err)
132 goto out;
133 }
134
135 err = 0;
136out:
137 return err;
138}
139
140static const struct xfrm_type ipcomp_type = {
141 .description = "IPCOMP4",
142 .owner = THIS_MODULE,
143 .proto = IPPROTO_COMP,
144 .init_state = ipcomp4_init_state,
145 .destructor = ipcomp_destroy,
146 .input = ipcomp_input,
147 .output = ipcomp_output
148};
149
150static const struct net_protocol ipcomp4_protocol = {
151 .handler = xfrm4_rcv,
152 .err_handler = ipcomp4_err,
153 .no_policy = 1,
154};
155
156static int __init ipcomp4_init(void)
157{
158 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
159 printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
160 return -EAGAIN;
161 }
162 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
163 printk(KERN_INFO "ipcomp init: can't add protocol\n");
164 xfrm_unregister_type(&ipcomp_type, AF_INET);
165 return -EAGAIN;
166 }
167 return 0;
168}
169
170static void __exit ipcomp4_fini(void)
171{
172 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
173 printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
174 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
175 printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
176}
177
178module_init(ipcomp4_init);
179module_exit(ipcomp4_fini);
180
181MODULE_LICENSE("GPL");
182MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
183MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
184
185MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
186
