[deliverable/linux.git] / net / ipv4 / ipcomp.c

/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * Todo:
 *   - Tunable compression parameters.
 *   - Compression stats.
 *   - Adaptive compression.
 */
#include <linux/module.h>
#include <linux/err.h>
#include <linux/rtnetlink.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/ipcomp.h>
#include <net/protocol.h>
#include <net/sock.h>

static void ipcomp4_err(struct sk_buff *skb, u32 info)
{
	struct net *net = dev_net(skb->dev);
	__be32 spi;
	const struct iphdr *iph = (const struct iphdr *)skb->data;
	struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	switch (icmp_hdr(skb)->type) {
	case ICMP_DEST_UNREACH:
		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
			return;
	case ICMP_REDIRECT:
		break;
	default:
		return;
	}

	spi = htonl(ntohs(ipch->cpi));
	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
			      spi, IPPROTO_COMP, AF_INET);
	if (!x)
		return;

	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
		ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
	else
		ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
	xfrm_state_put(x);
}

/* We always hold one tunnel user reference to indicate a tunnel */
static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
{
	struct net *net = xs_net(x);
	struct xfrm_state *t;

	t = xfrm_state_alloc(net);
	if (t == NULL)
		goto out;

	t->id.proto = IPPROTO_IPIP;
	t->id.spi = x->props.saddr.a4;
	t->id.daddr.a4 = x->id.daddr.a4;
	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	t->props.family = AF_INET;
	t->props.mode = x->props.mode;
	t->props.saddr.a4 = x->props.saddr.a4;
	t->props.flags = x->props.flags;
	t->props.extra_flags = x->props.extra_flags;
	memcpy(&t->mark, &x->mark, sizeof(t->mark));

	if (xfrm_init_state(t))
		goto error;

	atomic_set(&t->tunnel_users, 1);
out:
	return t;

error:
	t->km.state = XFRM_STATE_DEAD;
	xfrm_state_put(t);
	t = NULL;
	goto out;
}

/*
 * Must be protected by xfrm_cfg_mutex.  State and tunnel user references are
 * always incremented on success.
 */
static int ipcomp_tunnel_attach(struct xfrm_state *x)
{
	struct net *net = xs_net(x);
	int err = 0;
	struct xfrm_state *t;
	u32 mark = x->mark.v & x->mark.m;

	t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
			      x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
	if (!t) {
		t = ipcomp_tunnel_create(x);
		if (!t) {
			err = -EINVAL;
			goto out;
		}
		xfrm_state_insert(t);
		xfrm_state_hold(t);
	}
	x->tunnel = t;
	atomic_inc(&t->tunnel_users);
out:
	return err;
}

static int ipcomp4_init_state(struct xfrm_state *x)
{
	int err = -EINVAL;

	x->props.header_len = 0;
	switch (x->props.mode) {
	case XFRM_MODE_TRANSPORT:
		break;
	case XFRM_MODE_TUNNEL:
		x->props.header_len += sizeof(struct iphdr);
		break;
	default:
		goto out;
	}

	err = ipcomp_init_state(x);
	if (err)
		goto out;

	if (x->props.mode == XFRM_MODE_TUNNEL) {
		err = ipcomp_tunnel_attach(x);
		if (err)
			goto out;
	}

	err = 0;
out:
	return err;
}

static const struct xfrm_type ipcomp_type = {
	.description	= "IPCOMP4",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_COMP,
	.init_state	= ipcomp4_init_state,
	.destructor	= ipcomp_destroy,
	.input		= ipcomp_input,
	.output		= ipcomp_output
};

static const struct net_protocol ipcomp4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ipcomp4_err,
	.no_policy	=	1,
	.netns_ok	=	1,
};

static int __init ipcomp4_init(void)
{
	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
		pr_info("%s: can't add xfrm type\n", __func__);
		return -EAGAIN;
	}
	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
		pr_info("%s: can't add protocol\n", __func__);
		xfrm_unregister_type(&ipcomp_type, AF_INET);
		return -EAGAIN;
	}
	return 0;
}

static void __exit ipcomp4_fini(void)
{
	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
		pr_info("%s: can't remove protocol\n", __func__);
	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
		pr_info("%s: can't remove xfrm type\n", __func__);
}

module_init(ipcomp4_init);
module_exit(ipcomp4_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");

MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
Commit	Line	Data
1da177e4 LT	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
e905a9ed	8	* Software Foundation; either version 2 of the License, or (at your option)
1da177e4 LT	9	* any later version.
	10	*
	11	* Todo:
	12	* - Tunable compression parameters.
	13	* - Compression stats.
	14	* - Adaptive compression.
	15	*/
1da177e4	16	#include <linux/module.h>
4999f362	17	#include <linux/err.h>
1da177e4 LT	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>
14c85021	23	#include <net/protocol.h>
6fccab67	24	#include <net/sock.h>
1da177e4 LT	25
	26	static void ipcomp4_err(struct sk_buff *skb, u32 info)
	27	{
a92df254	28	struct net *net = dev_net(skb->dev);
a94cfd19	29	__be32 spi;
b71d1d42	30	const struct iphdr iph = (const struct iphdr )skb->data;
1da177e4 LT	31	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	32	struct xfrm_state *x;
	33
55be7a9c DM	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:
1da177e4	41	return;
55be7a9c	42	}
1da177e4	43
4195f814	44	spi = htonl(ntohs(ipch->cpi));
b71d1d42	45	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
e905a9ed	46	spi, IPPROTO_COMP, AF_INET);
1da177e4 LT	47	if (!x)
1da177e4 LT	48	return;
55be7a9c	49
387aa65a	50	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
55be7a9c	51	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
387aa65a	52	else
55be7a9c	53	ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
1da177e4 LT	54	xfrm_state_put(x);
	55	}
	56
e905a9ed	57	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	58	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
1da177e4 LT	59	{
a92df254	60	struct net *net = xs_net(x);
1da177e4	61	struct xfrm_state *t;
e905a9ed	62
a92df254	63	t = xfrm_state_alloc(net);
1da177e4 LT	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;
e40b3286	72	t->props.mode = x->props.mode;
1da177e4 LT	73	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	74	t->props.flags = x->props.flags;
a947b0a9	75	t->props.extra_flags = x->props.extra_flags;
bd55775c	76	memcpy(&t->mark, &x->mark, sizeof(t->mark));
72cb6962 HX	77
72cb6962 HX	78	if (xfrm_init_state(t))
1da177e4 LT	79	goto error;
1da177e4 LT	80
1da177e4 LT	81	atomic_set(&t->tunnel_users, 1);
	82	out:
	83	return t;
	84
	85	error:
	86	t->km.state = XFRM_STATE_DEAD;
	87	xfrm_state_put(t);
	88	t = NULL;
	89	goto out;
	90	}
	91
	92	/*
4a3e2f71	93	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	94	* always incremented on success.
	95	*/
	96	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	97	{
a92df254	98	struct net *net = xs_net(x);
1da177e4 LT	99	int err = 0;
1da177e4 LT	100	struct xfrm_state *t;
bd55775c	101	u32 mark = x->mark.v & x->mark.m;
1da177e4	102
bd55775c	103	t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	104	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	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);
	116	out:
	117	return err;
	118	}
	119
6fccab67	120	static int ipcomp4_init_state(struct xfrm_state *x)
1da177e4	121	{
2c3abab7	122	int err = -EINVAL;
1da177e4	123
e40b3286 HX	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
6fccab67 HX	135	err = ipcomp_init_state(x);
6fccab67 HX	136	if (err)
1da177e4 LT	137	goto out;
1da177e4 LT	138
7e49e6de	139	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	140	err = ipcomp_tunnel_attach(x);
1da177e4 LT	141	if (err)
10e7454e	142	goto out;
1da177e4 LT	143	}
1da177e4 LT	144
1da177e4 LT	145	err = 0;
	146	out:
	147	return err;
1da177e4 LT	148	}
1da177e4 LT	149
533cb5b0	150	static const struct xfrm_type ipcomp_type = {
1da177e4 LT	151	.description = "IPCOMP4",
	152	.owner = THIS_MODULE,
	153	.proto = IPPROTO_COMP,
6fccab67	154	.init_state = ipcomp4_init_state,
1da177e4 LT	155	.destructor = ipcomp_destroy,
	156	.input = ipcomp_input,
	157	.output = ipcomp_output
	158	};
	159
32613090	160	static const struct net_protocol ipcomp4_protocol = {
1da177e4 LT	161	.handler = xfrm4_rcv,
	162	.err_handler = ipcomp4_err,
	163	.no_policy = 1,
27000929	164	.netns_ok = 1,
1da177e4 LT	165	};
	166
	167	static int __init ipcomp4_init(void)
	168	{
	169	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
058bd4d2	170	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	171	return -EAGAIN;
	172	}
	173	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
058bd4d2	174	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	175	xfrm_unregister_type(&ipcomp_type, AF_INET);
	176	return -EAGAIN;
	177	}
	178	return 0;
	179	}
	180
	181	static void __exit ipcomp4_fini(void)
	182	{
	183	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
058bd4d2	184	pr_info("%s: can't remove protocol\n", __func__);
1da177e4	185	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
058bd4d2	186	pr_info("%s: can't remove xfrm type\n", __func__);
1da177e4 LT	187	}
	188
	189	module_init(ipcomp4_init);
	190	module_exit(ipcomp4_fini);
	191
	192	MODULE_LICENSE("GPL");
6fccab67	193	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
1da177e4 LT	194	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
1da177e4 LT	195
d3d6dd3a	196	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);