2 * IP Payload Compression Protocol (IPComp) - RFC3173.
4 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
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)
12 * - Tunable compression parameters.
13 * - Compression stats.
14 * - Adaptive compression.
16 #include <linux/module.h>
17 #include <linux/err.h>
18 #include <linux/rtnetlink.h>
22 #include <net/ipcomp.h>
23 #include <net/protocol.h>
26 static void ipcomp4_err(struct sk_buff *skb, u32 info)
28 struct net *net = dev_net(skb->dev);
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));
34 switch (icmp_hdr(skb)->type) {
35 case ICMP_DEST_UNREACH:
36 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
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);
50 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
51 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
53 ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
57 /* We always hold one tunnel user reference to indicate a tunnel */
58 static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
60 struct net *net = xs_net(x);
63 t = xfrm_state_alloc(net);
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 memcpy(&t->mark, &x->mark, sizeof(t->mark));
77 if (xfrm_init_state(t))
80 atomic_set(&t->tunnel_users, 1);
85 t->km.state = XFRM_STATE_DEAD;
92 * Must be protected by xfrm_cfg_mutex. State and tunnel user references are
93 * always incremented on success.
95 static int ipcomp_tunnel_attach(struct xfrm_state *x)
97 struct net *net = xs_net(x);
100 u32 mark = x->mark.v & x->mark.m;
102 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
103 x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
105 t = ipcomp_tunnel_create(x);
110 xfrm_state_insert(t);
114 atomic_inc(&t->tunnel_users);
119 static int ipcomp4_init_state(struct xfrm_state *x)
123 x->props.header_len = 0;
124 switch (x->props.mode) {
125 case XFRM_MODE_TRANSPORT:
127 case XFRM_MODE_TUNNEL:
128 x->props.header_len += sizeof(struct iphdr);
134 err = ipcomp_init_state(x);
138 if (x->props.mode == XFRM_MODE_TUNNEL) {
139 err = ipcomp_tunnel_attach(x);
149 static const struct xfrm_type ipcomp_type = {
150 .description = "IPCOMP4",
151 .owner = THIS_MODULE,
152 .proto = IPPROTO_COMP,
153 .init_state = ipcomp4_init_state,
154 .destructor = ipcomp_destroy,
155 .input = ipcomp_input,
156 .output = ipcomp_output
159 static const struct net_protocol ipcomp4_protocol = {
160 .handler = xfrm4_rcv,
161 .err_handler = ipcomp4_err,
165 static int __init ipcomp4_init(void)
167 if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
168 pr_info("%s: can't add xfrm type\n", __func__);
171 if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
172 pr_info("%s: can't add protocol\n", __func__);
173 xfrm_unregister_type(&ipcomp_type, AF_INET);
179 static void __exit ipcomp4_fini(void)
181 if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
182 pr_info("%s: can't remove protocol\n", __func__);
183 if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
184 pr_info("%s: can't remove xfrm type\n", __func__);
187 module_init(ipcomp4_init);
188 module_exit(ipcomp4_fini);
190 MODULE_LICENSE("GPL");
191 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
192 MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
194 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);