[linux-2.6-block.git] / net / ipv4 / ipcomp.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
 *
 * 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, IPPROTO_COMP);
	else
		ipv4_redirect(skb, net, 0, IPPROTO_COMP);
	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__);
	xfrm_unregister_type(&ipcomp_type, AF_INET);
}

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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* IP Payload Compression Protocol (IPComp) - RFC3173.
	4	*
	5	* Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
	6	*
1da177e4 LT	7	* Todo:
	8	* - Tunable compression parameters.
	9	* - Compression stats.
	10	* - Adaptive compression.
	11	*/
1da177e4	12	#include <linux/module.h>
4999f362	13	#include <linux/err.h>
1da177e4 LT	14	#include <linux/rtnetlink.h>
	15	#include <net/ip.h>
	16	#include <net/xfrm.h>
	17	#include <net/icmp.h>
	18	#include <net/ipcomp.h>
14c85021	19	#include <net/protocol.h>
6fccab67	20	#include <net/sock.h>
1da177e4	21
d099160e	22	static int ipcomp4_err(struct sk_buff *skb, u32 info)
1da177e4	23	{
a92df254	24	struct net *net = dev_net(skb->dev);
a94cfd19	25	__be32 spi;
b71d1d42	26	const struct iphdr iph = (const struct iphdr )skb->data;
1da177e4 LT	27	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	28	struct xfrm_state *x;
	29
55be7a9c DM	30	switch (icmp_hdr(skb)->type) {
	31	case ICMP_DEST_UNREACH:
	32	if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
d099160e	33	return 0;
55be7a9c DM	34	case ICMP_REDIRECT:
	35	break;
	36	default:
d099160e	37	return 0;
55be7a9c	38	}
1da177e4	39
4195f814	40	spi = htonl(ntohs(ipch->cpi));
b71d1d42	41	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
e905a9ed	42	spi, IPPROTO_COMP, AF_INET);
1da177e4	43	if (!x)
d099160e	44	return 0;
55be7a9c	45
387aa65a	46	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
d888f396	47	ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
387aa65a	48	else
1042caa7	49	ipv4_redirect(skb, net, 0, IPPROTO_COMP);
1da177e4	50	xfrm_state_put(x);
d099160e SK	51
d099160e SK	52	return 0;
1da177e4 LT	53	}
1da177e4 LT	54
e905a9ed	55	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	56	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
1da177e4 LT	57	{
a92df254	58	struct net *net = xs_net(x);
1da177e4	59	struct xfrm_state *t;
e905a9ed	60
a92df254	61	t = xfrm_state_alloc(net);
51456b29	62	if (!t)
1da177e4 LT	63	goto out;
	64
	65	t->id.proto = IPPROTO_IPIP;
	66	t->id.spi = x->props.saddr.a4;
	67	t->id.daddr.a4 = x->id.daddr.a4;
	68	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	69	t->props.family = AF_INET;
e40b3286	70	t->props.mode = x->props.mode;
1da177e4 LT	71	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	72	t->props.flags = x->props.flags;
a947b0a9	73	t->props.extra_flags = x->props.extra_flags;
bd55775c	74	memcpy(&t->mark, &x->mark, sizeof(t->mark));
72cb6962 HX	75
72cb6962 HX	76	if (xfrm_init_state(t))
1da177e4 LT	77	goto error;
1da177e4 LT	78
1da177e4 LT	79	atomic_set(&t->tunnel_users, 1);
	80	out:
	81	return t;
	82
	83	error:
	84	t->km.state = XFRM_STATE_DEAD;
	85	xfrm_state_put(t);
	86	t = NULL;
	87	goto out;
	88	}
	89
	90	/*
4a3e2f71	91	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	92	* always incremented on success.
	93	*/
	94	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	95	{
a92df254	96	struct net *net = xs_net(x);
1da177e4 LT	97	int err = 0;
1da177e4 LT	98	struct xfrm_state *t;
bd55775c	99	u32 mark = x->mark.v & x->mark.m;
1da177e4	100
bd55775c	101	t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	102	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	103	if (!t) {
	104	t = ipcomp_tunnel_create(x);
	105	if (!t) {
	106	err = -EINVAL;
	107	goto out;
	108	}
	109	xfrm_state_insert(t);
	110	xfrm_state_hold(t);
	111	}
	112	x->tunnel = t;
	113	atomic_inc(&t->tunnel_users);
	114	out:
	115	return err;
	116	}
	117
6fccab67	118	static int ipcomp4_init_state(struct xfrm_state *x)
1da177e4	119	{
2c3abab7	120	int err = -EINVAL;
1da177e4	121
e40b3286 HX	122	x->props.header_len = 0;
	123	switch (x->props.mode) {
	124	case XFRM_MODE_TRANSPORT:
	125	break;
	126	case XFRM_MODE_TUNNEL:
	127	x->props.header_len += sizeof(struct iphdr);
	128	break;
	129	default:
	130	goto out;
	131	}
	132
6fccab67 HX	133	err = ipcomp_init_state(x);
6fccab67 HX	134	if (err)
1da177e4 LT	135	goto out;
1da177e4 LT	136
7e49e6de	137	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	138	err = ipcomp_tunnel_attach(x);
1da177e4 LT	139	if (err)
10e7454e	140	goto out;
1da177e4 LT	141	}
1da177e4 LT	142
1da177e4 LT	143	err = 0;
	144	out:
	145	return err;
1da177e4 LT	146	}
1da177e4 LT	147
d099160e SK	148	static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
	149	{
	150	return 0;
	151	}
	152
533cb5b0	153	static const struct xfrm_type ipcomp_type = {
1da177e4 LT	154	.description = "IPCOMP4",
	155	.owner = THIS_MODULE,
	156	.proto = IPPROTO_COMP,
6fccab67	157	.init_state = ipcomp4_init_state,
1da177e4 LT	158	.destructor = ipcomp_destroy,
	159	.input = ipcomp_input,
	160	.output = ipcomp_output
	161	};
	162
d099160e	163	static struct xfrm4_protocol ipcomp4_protocol = {
1da177e4	164	.handler = xfrm4_rcv,
d099160e SK	165	.input_handler = xfrm_input,
d099160e SK	166	.cb_handler = ipcomp4_rcv_cb,
1da177e4	167	.err_handler = ipcomp4_err,
d099160e	168	.priority = 0,
1da177e4 LT	169	};
	170
	171	static int __init ipcomp4_init(void)
	172	{
	173	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
058bd4d2	174	pr_info("%s: can't add xfrm type\n", __func__);
1da177e4 LT	175	return -EAGAIN;
1da177e4 LT	176	}
d099160e	177	if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
058bd4d2	178	pr_info("%s: can't add protocol\n", __func__);
1da177e4 LT	179	xfrm_unregister_type(&ipcomp_type, AF_INET);
	180	return -EAGAIN;
	181	}
	182	return 0;
	183	}
	184
	185	static void __exit ipcomp4_fini(void)
	186	{
d099160e	187	if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
058bd4d2	188	pr_info("%s: can't remove protocol\n", __func__);
4f518e80	189	xfrm_unregister_type(&ipcomp_type, AF_INET);
1da177e4 LT	190	}
	191
	192	module_init(ipcomp4_init);
	193	module_exit(ipcomp4_fini);
	194
	195	MODULE_LICENSE("GPL");
6fccab67	196	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
1da177e4 LT	197	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
1da177e4 LT	198
d3d6dd3a	199	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);