inet: Fix __inet_inherit_port() to correctly increment bsockets and num_owners
[linux-2.6.git] / net / ipv4 / ipcomp.c
1 /*
2  * IP Payload Compression Protocol (IPComp) - RFC3173.
3  *
4  * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  *
11  * Todo:
12  *   - Tunable compression parameters.
13  *   - Compression stats.
14  *   - Adaptive compression.
15  */
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
26 static void ipcomp4_err(struct sk_buff *skb, u32 info)
27 {
28         struct net *net = dev_net(skb->dev);
29         __be32 spi;
30         struct iphdr *iph = (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, (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 /* We always hold one tunnel user reference to indicate a tunnel */
49 static 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);
72 out:
73         return t;
74
75 error:
76         t->km.state = XFRM_STATE_DEAD;
77         xfrm_state_put(t);
78         t = NULL;
79         goto out;
80 }
81
82 /*
83  * Must be protected by xfrm_cfg_mutex.  State and tunnel user references are
84  * always incremented on success.
85  */
86 static 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);
106 out:
107         return err;
108 }
109
110 static 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;
136 out:
137         return err;
138 }
139
140 static 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
150 static const struct net_protocol ipcomp4_protocol = {
151         .handler        =       xfrm4_rcv,
152         .err_handler    =       ipcomp4_err,
153         .no_policy      =       1,
154 };
155
156 static 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
170 static 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
178 module_init(ipcomp4_init);
179 module_exit(ipcomp4_fini);
180
181 MODULE_LICENSE("GPL");
182 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
183 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
184
185 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);