[mirror_ubuntu-focal-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 void ipcomp4_err(struct sk_buff *skb, u32 info)
{
	struct net *net = dev_net(skb->dev);
	__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(net, (xfrm_address_t *)&iph->daddr,
			      spi, IPPROTO_COMP, AF_INET);
	if (!x)
		return;
	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
		 spi, &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 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;

	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;

	t = xfrm_state_lookup(net, (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,
};

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	{
a92df254	28	struct net *net = dev_net(skb->dev);
a94cfd19	29	__be32 spi;
1da177e4 LT	30	struct iphdr iph = (struct iphdr )skb->data;
	31	struct ip_comp_hdr ipch = (struct ip_comp_hdr )(skb->data+(iph->ihl<<2));
	32	struct xfrm_state *x;
	33
88c7664f ACM	34	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
88c7664f ACM	35	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
1da177e4 LT	36	return;
1da177e4 LT	37
4195f814	38	spi = htonl(ntohs(ipch->cpi));
a92df254	39	x = xfrm_state_lookup(net, (xfrm_address_t *)&iph->daddr,
e905a9ed	40	spi, IPPROTO_COMP, AF_INET);
1da177e4 LT	41	if (!x)
1da177e4 LT	42	return;
673d57e7 HH	43	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
673d57e7 HH	44	spi, &iph->daddr);
1da177e4 LT	45	xfrm_state_put(x);
	46	}
	47
e905a9ed	48	/* We always hold one tunnel user reference to indicate a tunnel */
1da177e4 LT	49	static struct xfrm_state ipcomp_tunnel_create(struct xfrm_state x)
1da177e4 LT	50	{
a92df254	51	struct net *net = xs_net(x);
1da177e4	52	struct xfrm_state *t;
e905a9ed	53
a92df254	54	t = xfrm_state_alloc(net);
1da177e4 LT	55	if (t == NULL)
	56	goto out;
	57
	58	t->id.proto = IPPROTO_IPIP;
	59	t->id.spi = x->props.saddr.a4;
	60	t->id.daddr.a4 = x->id.daddr.a4;
	61	memcpy(&t->sel, &x->sel, sizeof(t->sel));
	62	t->props.family = AF_INET;
e40b3286	63	t->props.mode = x->props.mode;
1da177e4 LT	64	t->props.saddr.a4 = x->props.saddr.a4;
1da177e4 LT	65	t->props.flags = x->props.flags;
72cb6962 HX	66
72cb6962 HX	67	if (xfrm_init_state(t))
1da177e4 LT	68	goto error;
1da177e4 LT	69
1da177e4 LT	70	atomic_set(&t->tunnel_users, 1);
	71	out:
	72	return t;
	73
	74	error:
	75	t->km.state = XFRM_STATE_DEAD;
	76	xfrm_state_put(t);
	77	t = NULL;
	78	goto out;
	79	}
	80
	81	/*
4a3e2f71	82	* Must be protected by xfrm_cfg_mutex. State and tunnel user references are
1da177e4 LT	83	* always incremented on success.
	84	*/
	85	static int ipcomp_tunnel_attach(struct xfrm_state *x)
	86	{
a92df254	87	struct net *net = xs_net(x);
1da177e4 LT	88	int err = 0;
	89	struct xfrm_state *t;
	90
a92df254	91	t = xfrm_state_lookup(net, (xfrm_address_t *)&x->id.daddr.a4,
e905a9ed	92	x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
1da177e4 LT	93	if (!t) {
	94	t = ipcomp_tunnel_create(x);
	95	if (!t) {
	96	err = -EINVAL;
	97	goto out;
	98	}
	99	xfrm_state_insert(t);
	100	xfrm_state_hold(t);
	101	}
	102	x->tunnel = t;
	103	atomic_inc(&t->tunnel_users);
	104	out:
	105	return err;
	106	}
	107
6fccab67	108	static int ipcomp4_init_state(struct xfrm_state *x)
1da177e4	109	{
2c3abab7	110	int err = -EINVAL;
1da177e4	111
e40b3286 HX	112	x->props.header_len = 0;
	113	switch (x->props.mode) {
	114	case XFRM_MODE_TRANSPORT:
	115	break;
	116	case XFRM_MODE_TUNNEL:
	117	x->props.header_len += sizeof(struct iphdr);
	118	break;
	119	default:
	120	goto out;
	121	}
	122
6fccab67 HX	123	err = ipcomp_init_state(x);
6fccab67 HX	124	if (err)
1da177e4 LT	125	goto out;
1da177e4 LT	126
7e49e6de	127	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	128	err = ipcomp_tunnel_attach(x);
1da177e4 LT	129	if (err)
10e7454e	130	goto out;
1da177e4 LT	131	}
1da177e4 LT	132
1da177e4 LT	133	err = 0;
	134	out:
	135	return err;
1da177e4 LT	136	}
1da177e4 LT	137
533cb5b0	138	static const struct xfrm_type ipcomp_type = {
1da177e4 LT	139	.description = "IPCOMP4",
	140	.owner = THIS_MODULE,
	141	.proto = IPPROTO_COMP,
6fccab67	142	.init_state = ipcomp4_init_state,
1da177e4 LT	143	.destructor = ipcomp_destroy,
	144	.input = ipcomp_input,
	145	.output = ipcomp_output
	146	};
	147
32613090	148	static const struct net_protocol ipcomp4_protocol = {
1da177e4 LT	149	.handler = xfrm4_rcv,
	150	.err_handler = ipcomp4_err,
	151	.no_policy = 1,
	152	};
	153
	154	static int __init ipcomp4_init(void)
	155	{
	156	if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
	157	printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
	158	return -EAGAIN;
	159	}
	160	if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
	161	printk(KERN_INFO "ipcomp init: can't add protocol\n");
	162	xfrm_unregister_type(&ipcomp_type, AF_INET);
	163	return -EAGAIN;
	164	}
	165	return 0;
	166	}
	167
	168	static void __exit ipcomp4_fini(void)
	169	{
	170	if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
	171	printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
	172	if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
	173	printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
	174	}
	175
	176	module_init(ipcomp4_init);
	177	module_exit(ipcomp4_fini);
	178
	179	MODULE_LICENSE("GPL");
6fccab67	180	MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
1da177e4 LT	181	MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
1da177e4 LT	182
d3d6dd3a	183	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);