[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)
{
	__be32 spi;
	struct iphdr *iph = (struct iphdr *)skb->data;
	struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
	    icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
		return;

	spi = htonl(ntohs(ipch->cpi));
	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
			      spi, IPPROTO_COMP, AF_INET);
	if (!x)
		return;
	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIPQUAD_FMT "\n",
		 spi, NIPQUAD(iph->daddr));
	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 xfrm_state *t;

	t = xfrm_state_alloc();
	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;

	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)
{
	int err = 0;
	struct xfrm_state *t;

	t = xfrm_state_lookup((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;
	struct ipcomp_data *ipcd;
	struct xfrm_algo_desc *calg_desc;

	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 error_tunnel;
	}

	err = 0;
out:
	return err;

error_tunnel:
	ipcomp_destroy(x);
	goto out;
}

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 net_protocol ipcomp4_protocol = {
	.handler	=	xfrm4_rcv,
	.err_handler	=	ipcomp4_err,
	.no_policy	=	1,
};

static int __init ipcomp4_init(void)
{
	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
		printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
		return -EAGAIN;
	}
	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
		printk(KERN_INFO "ipcomp init: can't add protocol\n");
		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)
		printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
		printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
}

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	{
a94cfd19	28	__be32 spi;
1da177e4 LT	29	struct iphdr iph = (struct iphdr )skb->data;
	30	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	31	struct xfrm_state *x;
	32
88c7664f ACM	33	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	34	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	35	return;
1da177e4 LT	36
4195f814	37	spi = htonl(ntohs(ipch->cpi));
1da177e4	38	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
e905a9ed	39	spi, IPPROTO_COMP, AF_INET);
1da177e4 LT	40	if (!x)
1da177e4 LT	41	return;
a7d632b6	42	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIPQUAD_FMT "\n",
64ce2073	43	spi, NIPQUAD(iph->daddr));
1da177e4 LT	44	xfrm_state_put(x);
	45	}
	46
e905a9ed	47	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	48	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
	49	{
	50	struct xfrm_state *t;
e905a9ed	51
1da177e4 LT	52	t = xfrm_state_alloc();
	53	if (t == NULL)
	54	goto out;
	55
	56	t->id.proto = IPPROTO_IPIP;
	57	t->id.spi = x->props.saddr.a4;
	58	t->id.daddr.a4 = x->id.daddr.a4;
	59	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	60	t->props.family = AF_INET;
e40b3286	61	t->props.mode = x->props.mode;
1da177e4 LT	62	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	63	t->props.flags = x->props.flags;
72cb6962 HX	64
72cb6962 HX	65	if (xfrm_init_state(t))
1da177e4 LT	66	goto error;
1da177e4 LT	67
1da177e4 LT	68	atomic_set(&t->tunnel_users, 1);
	69	out:
	70	return t;
	71
	72	error:
	73	t->km.state = XFRM_STATE_DEAD;
	74	xfrm_state_put(t);
	75	t = NULL;
	76	goto out;
	77	}
	78
	79	/*
4a3e2f71	80	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	81	* always incremented on success.
	82	*/
	83	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	84	{
	85	int err = 0;
	86	struct xfrm_state *t;
	87
	88	t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	89	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	90	if (!t) {
	91	t = ipcomp_tunnel_create(x);
	92	if (!t) {
	93	err = -EINVAL;
	94	goto out;
	95	}
	96	xfrm_state_insert(t);
	97	xfrm_state_hold(t);
	98	}
	99	x->tunnel = t;
	100	atomic_inc(&t->tunnel_users);
	101	out:
	102	return err;
	103	}
	104
6fccab67	105	static int ipcomp4_init_state(struct xfrm_state *x)
1da177e4 LT	106	{
	107	int err;
	108	struct ipcomp_data *ipcd;
	109	struct xfrm_algo_desc *calg_desc;
	110
e40b3286 HX	111	x->props.header_len = 0;
	112	switch (x->props.mode) {
	113	case XFRM_MODE_TRANSPORT:
	114	break;
	115	case XFRM_MODE_TUNNEL:
	116	x->props.header_len += sizeof(struct iphdr);
	117	break;
	118	default:
	119	goto out;
	120	}
	121
6fccab67 HX	122	err = ipcomp_init_state(x);
6fccab67 HX	123	if (err)
1da177e4 LT	124	goto out;
1da177e4 LT	125
7e49e6de	126	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	127	err = ipcomp_tunnel_attach(x);
	128	if (err)
	129	goto error_tunnel;
	130	}
	131
1da177e4 LT	132	err = 0;
	133	out:
	134	return err;
	135
	136	error_tunnel:
6fccab67	137	ipcomp_destroy(x);
1da177e4 LT	138	goto out;
	139	}
	140
533cb5b0	141	static const struct xfrm_type ipcomp_type = {
1da177e4 LT	142	.description = "IPCOMP4",
	143	.owner = THIS_MODULE,
	144	.proto = IPPROTO_COMP,
6fccab67	145	.init_state = ipcomp4_init_state,
1da177e4 LT	146	.destructor = ipcomp_destroy,
	147	.input = ipcomp_input,
	148	.output = ipcomp_output
	149	};
	150
	151	static struct net_protocol ipcomp4_protocol = {
	152	.handler = xfrm4_rcv,
	153	.err_handler = ipcomp4_err,
	154	.no_policy = 1,
	155	};
	156
	157	static int __init ipcomp4_init(void)
	158	{
	159	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
	160	printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
	161	return -EAGAIN;
	162	}
	163	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
	164	printk(KERN_INFO "ipcomp init: can't add protocol\n");
	165	xfrm_unregister_type(&ipcomp_type, AF_INET);
	166	return -EAGAIN;
	167	}
	168	return 0;
	169	}
	170
	171	static void __exit ipcomp4_fini(void)
	172	{
	173	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
	174	printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	175	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
	176	printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
	177	}
	178
	179	module_init(ipcomp4_init);
	180	module_exit(ipcomp4_fini);
	181
	182	MODULE_LICENSE("GPL");
6fccab67	183	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
1da177e4 LT	184	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
1da177e4 LT	185
d3d6dd3a	186	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);