[mirror_ubuntu-artful-kernel.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 int 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 0;
	case ICMP_REDIRECT:
		break;
	default:
		return 0;
	}

	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 0;

	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);

	return 0;
}

/* 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)
		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 int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
{
	return 0;
}

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 struct xfrm4_protocol ipcomp4_protocol = {
	.handler	=	xfrm4_rcv,
	.input_handler	=	xfrm_input,
	.cb_handler	=	ipcomp4_rcv_cb,
	.err_handler	=	ipcomp4_err,
	.priority	=	0,
};

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 (xfrm4_protocol_register(&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 (xfrm4_protocol_deregister(&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	25
d099160e	26	static int ipcomp4_err(struct sk_buff *skb, u32 info)
1da177e4	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)
d099160e	37	return 0;
55be7a9c DM	38	case ICMP_REDIRECT:
	39	break;
	40	default:
d099160e	41	return 0;
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	47	if (!x)
d099160e	48	return 0;
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	54	xfrm_state_put(x);
d099160e SK	55
d099160e SK	56	return 0;
1da177e4 LT	57	}
1da177e4 LT	58
e905a9ed	59	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	60	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
1da177e4 LT	61	{
a92df254	62	struct net *net = xs_net(x);
1da177e4	63	struct xfrm_state *t;
e905a9ed	64
a92df254	65	t = xfrm_state_alloc(net);
51456b29	66	if (!t)
1da177e4 LT	67	goto out;
	68
	69	t->id.proto = IPPROTO_IPIP;
	70	t->id.spi = x->props.saddr.a4;
	71	t->id.daddr.a4 = x->id.daddr.a4;
	72	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	73	t->props.family = AF_INET;
e40b3286	74	t->props.mode = x->props.mode;
1da177e4 LT	75	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	76	t->props.flags = x->props.flags;
a947b0a9	77	t->props.extra_flags = x->props.extra_flags;
bd55775c	78	memcpy(&t->mark, &x->mark, sizeof(t->mark));
72cb6962 HX	79
72cb6962 HX	80	if (xfrm_init_state(t))
1da177e4 LT	81	goto error;
1da177e4 LT	82
1da177e4 LT	83	atomic_set(&t->tunnel_users, 1);
	84	out:
	85	return t;
	86
	87	error:
	88	t->km.state = XFRM_STATE_DEAD;
	89	xfrm_state_put(t);
	90	t = NULL;
	91	goto out;
	92	}
	93
	94	/*
4a3e2f71	95	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	96	* always incremented on success.
	97	*/
	98	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	99	{
a92df254	100	struct net *net = xs_net(x);
1da177e4 LT	101	int err = 0;
1da177e4 LT	102	struct xfrm_state *t;
bd55775c	103	u32 mark = x->mark.v & x->mark.m;
1da177e4	104
bd55775c	105	t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	106	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	107	if (!t) {
	108	t = ipcomp_tunnel_create(x);
	109	if (!t) {
	110	err = -EINVAL;
	111	goto out;
	112	}
	113	xfrm_state_insert(t);
	114	xfrm_state_hold(t);
	115	}
	116	x->tunnel = t;
	117	atomic_inc(&t->tunnel_users);
	118	out:
	119	return err;
	120	}
	121
6fccab67	122	static int ipcomp4_init_state(struct xfrm_state *x)
1da177e4	123	{
2c3abab7	124	int err = -EINVAL;
1da177e4	125
e40b3286 HX	126	x->props.header_len = 0;
	127	switch (x->props.mode) {
	128	case XFRM_MODE_TRANSPORT:
	129	break;
	130	case XFRM_MODE_TUNNEL:
	131	x->props.header_len += sizeof(struct iphdr);
	132	break;
	133	default:
	134	goto out;
	135	}
	136
6fccab67 HX	137	err = ipcomp_init_state(x);
6fccab67 HX	138	if (err)
1da177e4 LT	139	goto out;
1da177e4 LT	140
7e49e6de	141	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	142	err = ipcomp_tunnel_attach(x);
1da177e4 LT	143	if (err)
10e7454e	144	goto out;
1da177e4 LT	145	}
1da177e4 LT	146
1da177e4 LT	147	err = 0;
	148	out:
	149	return err;
1da177e4 LT	150	}
1da177e4 LT	151
d099160e SK	152	static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
	153	{
	154	return 0;
	155	}
	156
533cb5b0	157	static const struct xfrm_type ipcomp_type = {
1da177e4 LT	158	.description = "IPCOMP4",
	159	.owner = THIS_MODULE,
	160	.proto = IPPROTO_COMP,
6fccab67	161	.init_state = ipcomp4_init_state,
1da177e4 LT	162	.destructor = ipcomp_destroy,
	163	.input = ipcomp_input,
	164	.output = ipcomp_output
	165	};
	166
d099160e	167	static struct xfrm4_protocol ipcomp4_protocol = {
1da177e4	168	.handler = xfrm4_rcv,
d099160e SK	169	.input_handler = xfrm_input,
d099160e SK	170	.cb_handler = ipcomp4_rcv_cb,
1da177e4	171	.err_handler = ipcomp4_err,
d099160e	172	.priority = 0,
1da177e4 LT	173	};
	174
	175	static int __init ipcomp4_init(void)
	176	{
	177	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
058bd4d2	178	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	179	return -EAGAIN;
1da177e4 LT	180	}
d099160e	181	if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
058bd4d2	182	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	183	xfrm_unregister_type(&ipcomp_type, AF_INET);
	184	return -EAGAIN;
	185	}
	186	return 0;
	187	}
	188
	189	static void __exit ipcomp4_fini(void)
	190	{
d099160e	191	if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
058bd4d2	192	pr_info("%s: can't remove protocol\n", __func__);
1da177e4	193	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
058bd4d2	194	pr_info("%s: can't remove xfrm type\n", __func__);
1da177e4 LT	195	}
	196
	197	module_init(ipcomp4_init);
	198	module_exit(ipcomp4_fini);
	199
	200	MODULE_LICENSE("GPL");
6fccab67	201	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
1da177e4 LT	202	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
1da177e4 LT	203
d3d6dd3a	204	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);