[mirror_ovs.git] / datapath / linux / compat / gre.c

/*
 * Copyright (c) 2007-2013 Nicira, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#include <linux/version.h>
#include <linux/kconfig.h>
#include <linux/module.h>
#include <linux/if.h>
#include <linux/if_tunnel.h>
#include <linux/icmp.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>

#include <net/gre.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/xfrm.h>

#include "gso.h"

#ifndef HAVE_METADATA_DST
#if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)

#ifndef HAVE_GRE_HANDLE_OFFLOADS

#ifndef HAVE_GRE_CISCO_REGISTER

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)

#define GREPROTO_CISCO		0
#define GREPROTO_MAX		1

struct gre_protocol {
	int  (*handler)(struct sk_buff *skb);
};
static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;

static int gre_rcv(struct sk_buff *skb)
{
	const struct gre_protocol *proto;
	u8 ver;
	int ret;

	if (!pskb_may_pull(skb, 12))
		goto drop;

	ver = skb->data[1] & 0x7f;
	if (ver >= GREPROTO_MAX)
		goto drop;

	rcu_read_lock();
	proto = rcu_dereference(gre_proto[ver]);
	if (!proto || !proto->handler)
		goto drop_unlock;
	ret = proto->handler(skb);
	rcu_read_unlock();
	return ret;

drop_unlock:
	rcu_read_unlock();
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static const struct net_protocol net_gre_protocol = {
	.handler     = gre_rcv,
	.netns_ok    = 1,
};

static int gre_add_protocol(const struct gre_protocol *proto, u8 version)
{
	if (version >= GREPROTO_MAX)
		return -EINVAL;

	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
		pr_err("%s: cannot register gre protocol handler\n", __func__);
		return -EAGAIN;
	}

	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
		0 : -EBUSY;
}

static int gre_del_protocol(const struct gre_protocol *proto, u8 version)
{
	int ret;

	if (version >= GREPROTO_MAX)
		return -EINVAL;

	ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
		0 : -EBUSY;

	if (ret)
		return ret;

	synchronize_net();

	ret = inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
	if (ret)
		return ret;

	return 0;
}

#endif

static __sum16 check_checksum(struct sk_buff *skb)
{
	__sum16 csum = 0;

	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
		csum = csum_fold(skb->csum);

		if (!csum)
			break;
		/* Fall through. */

	case CHECKSUM_NONE:
		skb->csum = 0;
		csum = __skb_checksum_complete(skb);
		skb->ip_summed = CHECKSUM_COMPLETE;
		break;
	}

	return csum;
}

#define ip_gre_calc_hlen rpl_ip_gre_calc_hlen
static int ip_gre_calc_hlen(__be16 o_flags)
{
	int addend = 4;

	if (o_flags & TUNNEL_CSUM)
		addend += 4;
	if (o_flags & TUNNEL_KEY)
		addend += 4;
	if (o_flags & TUNNEL_SEQ)
		addend += 4;
	return addend;
}

#define gre_flags_to_tnl_flags rpl_gre_flags_to_tnl_flags
static __be16 gre_flags_to_tnl_flags(__be16 flags)
{
	__be16 tflags = 0;

	if (flags & GRE_CSUM)
		tflags |= TUNNEL_CSUM;
	if (flags & GRE_ROUTING)
		tflags |= TUNNEL_ROUTING;
	if (flags & GRE_KEY)
		tflags |= TUNNEL_KEY;
	if (flags & GRE_SEQ)
		tflags |= TUNNEL_SEQ;
	if (flags & GRE_STRICT)
		tflags |= TUNNEL_STRICT;
	if (flags & GRE_REC)
		tflags |= TUNNEL_REC;
	if (flags & GRE_VERSION)
		tflags |= TUNNEL_VERSION;

	return tflags;
}

static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
			    bool *csum_err)
{
	unsigned int ip_hlen = ip_hdrlen(skb);
	struct gre_base_hdr *greh;
	__be32 *options;
	int hdr_len;

	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
		return -EINVAL;

	greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
		return -EINVAL;

	tpi->flags = gre_flags_to_tnl_flags(greh->flags);
	hdr_len = ip_gre_calc_hlen(tpi->flags);

	if (!pskb_may_pull(skb, hdr_len))
		return -EINVAL;

	greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
	tpi->proto = greh->protocol;

	options = (__be32 *)(greh + 1);
	if (greh->flags & GRE_CSUM) {
		if (check_checksum(skb)) {
			*csum_err = true;
			return -EINVAL;
		}
		options++;
	}

	if (greh->flags & GRE_KEY) {
		tpi->key = *options;
		options++;
	} else
		tpi->key = 0;

	if (unlikely(greh->flags & GRE_SEQ)) {
		tpi->seq = *options;
		options++;
	} else
		tpi->seq = 0;

	/* WCCP version 1 and 2 protocol decoding.
	 * - Change protocol to IP
	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
	 */
	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
		tpi->proto = htons(ETH_P_IP);
		if ((*(u8 *)options & 0xF0) != 0x40) {
			hdr_len += 4;
			if (!pskb_may_pull(skb, hdr_len))
				return -EINVAL;
		}
	}

	return iptunnel_pull_header(skb, hdr_len, tpi->proto);
}

static struct gre_cisco_protocol __rcu *gre_cisco_proto;
static int gre_cisco_rcv(struct sk_buff *skb)
{
	struct tnl_ptk_info tpi;
	bool csum_err = false;
	struct gre_cisco_protocol *proto;

	rcu_read_lock();
	proto = rcu_dereference(gre_cisco_proto);
	if (!proto)
		goto drop;

	if (parse_gre_header(skb, &tpi, &csum_err) < 0)
		goto drop;
	proto->handler(skb, &tpi);
	rcu_read_unlock();
	return 0;

drop:
	rcu_read_unlock();
	kfree_skb(skb);
	return 0;
}

static const struct gre_protocol ipgre_protocol = {
	.handler	=	gre_cisco_rcv,
};

int rpl_gre_cisco_register(struct gre_cisco_protocol *newp)
{
	int err;

	err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
	if (err) {
		pr_warn("%s: cannot register gre_cisco protocol handler\n", __func__);
		return err;
	}


	return (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, NULL, newp) == NULL) ?
		0 : -EBUSY;
}
EXPORT_SYMBOL_GPL(rpl_gre_cisco_register);

int rpl_gre_cisco_unregister(struct gre_cisco_protocol *proto)
{
	int ret;

	ret = (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, proto, NULL) == proto) ?
		0 : -EINVAL;

	if (ret)
		return ret;

	synchronize_net();
	ret = gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
	return ret;
}
EXPORT_SYMBOL_GPL(rpl_gre_cisco_unregister);

#endif /* !HAVE_GRE_CISCO_REGISTER */
#endif

#endif /* CONFIG_NET_IPGRE_DEMUX */
#endif /* HAVE_METADATA_DST */
Commit	Line	Data
5ebaf571 PS	1	/*
	2	* Copyright (c) 2007-2013 Nicira, Inc.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of version 2 of the GNU General Public
	6	* License as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful, but
	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public License
	14	* along with this program; if not, write to the Free Software
	15	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	16	* 02110-1301, USA
	17	*/
	18
29c71cfa	19	#include <linux/version.h>
2be0b371	20	#include <linux/kconfig.h>
5ebaf571 PS	21	#include <linux/module.h>
	22	#include <linux/if.h>
	23	#include <linux/if_tunnel.h>
	24	#include <linux/icmp.h>
	25	#include <linux/in.h>
	26	#include <linux/ip.h>
	27	#include <linux/kernel.h>
	28	#include <linux/kmod.h>
	29	#include <linux/netdevice.h>
	30	#include <linux/skbuff.h>
	31	#include <linux/spinlock.h>
	32
	33	#include <net/gre.h>
	34	#include <net/icmp.h>
	35	#include <net/protocol.h>
	36	#include <net/route.h>
	37	#include <net/xfrm.h>
	38
	39	#include "gso.h"
	40
e23775f2	41	#ifndef HAVE_METADATA_DST
9b928914 PS	42	#if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
9b928914 PS	43
e23775f2	44	#ifndef HAVE_GRE_HANDLE_OFFLOADS
9b928914	45
cc1d0dea	46	#ifndef HAVE_GRE_CISCO_REGISTER
5ebaf571	47
cc1d0dea	48	#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
5ebaf571	49
cc1d0dea PS	50	#define GREPROTO_CISCO 0
cc1d0dea PS	51	#define GREPROTO_MAX 1
5ebaf571	52
cc1d0dea PS	53	struct gre_protocol {
	54	int (handler)(struct sk_buff skb);
	55	};
	56	static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
	57
	58	static int gre_rcv(struct sk_buff *skb)
5ebaf571	59	{
cc1d0dea PS	60	const struct gre_protocol *proto;
	61	u8 ver;
	62	int ret;
5ebaf571	63
cc1d0dea PS	64	if (!pskb_may_pull(skb, 12))
cc1d0dea PS	65	goto drop;
5ebaf571	66
cc1d0dea PS	67	ver = skb->data[1] & 0x7f;
	68	if (ver >= GREPROTO_MAX)
	69	goto drop;
5ebaf571	70
cc1d0dea PS	71	rcu_read_lock();
	72	proto = rcu_dereference(gre_proto[ver]);
	73	if (!proto \|\| !proto->handler)
	74	goto drop_unlock;
	75	ret = proto->handler(skb);
	76	rcu_read_unlock();
	77	return ret;
	78
	79	drop_unlock:
	80	rcu_read_unlock();
	81	drop:
5ebaf571	82	kfree_skb(skb);
cc1d0dea	83	return NET_RX_DROP;
5ebaf571 PS	84	}
5ebaf571 PS	85
cc1d0dea PS	86	static const struct net_protocol net_gre_protocol = {
	87	.handler = gre_rcv,
	88	.netns_ok = 1,
	89	};
	90
	91	static int gre_add_protocol(const struct gre_protocol *proto, u8 version)
5ebaf571	92	{
cc1d0dea PS	93	if (version >= GREPROTO_MAX)
	94	return -EINVAL;
	95
	96	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
	97	pr_err("%s: cannot register gre protocol handler\n", __func__);
	98	return -EAGAIN;
	99	}
	100
	101	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
	102	0 : -EBUSY;
5ebaf571 PS	103	}
5ebaf571 PS	104
cc1d0dea	105	static int gre_del_protocol(const struct gre_protocol *proto, u8 version)
5ebaf571	106	{
cc1d0dea	107	int ret;
5ebaf571	108
cc1d0dea PS	109	if (version >= GREPROTO_MAX)
cc1d0dea PS	110	return -EINVAL;
5ebaf571	111
cc1d0dea PS	112	ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
cc1d0dea PS	113	0 : -EBUSY;
5ebaf571	114
cc1d0dea PS	115	if (ret)
cc1d0dea PS	116	return ret;
5ebaf571	117
cc1d0dea PS	118	synchronize_net();
	119
	120	ret = inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
	121	if (ret)
	122	return ret;
	123
	124	return 0;
5ebaf571 PS	125	}
5ebaf571 PS	126
cc1d0dea	127	#endif
9a27329d	128
5ebaf571 PS	129	static __sum16 check_checksum(struct sk_buff *skb)
	130	{
	131	__sum16 csum = 0;
	132
	133	switch (skb->ip_summed) {
	134	case CHECKSUM_COMPLETE:
	135	csum = csum_fold(skb->csum);
	136
	137	if (!csum)
	138	break;
	139	/* Fall through. */
	140
	141	case CHECKSUM_NONE:
	142	skb->csum = 0;
	143	csum = __skb_checksum_complete(skb);
	144	skb->ip_summed = CHECKSUM_COMPLETE;
	145	break;
	146	}
	147
	148	return csum;
	149	}
	150
e23775f2 PS	151	#define ip_gre_calc_hlen rpl_ip_gre_calc_hlen
	152	static int ip_gre_calc_hlen(__be16 o_flags)
	153	{
	154	int addend = 4;
	155
	156	if (o_flags & TUNNEL_CSUM)
	157	addend += 4;
	158	if (o_flags & TUNNEL_KEY)
	159	addend += 4;
	160	if (o_flags & TUNNEL_SEQ)
	161	addend += 4;
	162	return addend;
	163	}
	164
	165	#define gre_flags_to_tnl_flags rpl_gre_flags_to_tnl_flags
	166	static __be16 gre_flags_to_tnl_flags(__be16 flags)
	167	{
	168	__be16 tflags = 0;
	169
	170	if (flags & GRE_CSUM)
	171	tflags \|= TUNNEL_CSUM;
	172	if (flags & GRE_ROUTING)
	173	tflags \|= TUNNEL_ROUTING;
	174	if (flags & GRE_KEY)
	175	tflags \|= TUNNEL_KEY;
	176	if (flags & GRE_SEQ)
	177	tflags \|= TUNNEL_SEQ;
	178	if (flags & GRE_STRICT)
	179	tflags \|= TUNNEL_STRICT;
	180	if (flags & GRE_REC)
	181	tflags \|= TUNNEL_REC;
	182	if (flags & GRE_VERSION)
	183	tflags \|= TUNNEL_VERSION;
	184
	185	return tflags;
	186	}
	187
5ebaf571 PS	188	static int parse_gre_header(struct sk_buff skb, struct tnl_ptk_info tpi,
	189	bool *csum_err)
	190	{
	191	unsigned int ip_hlen = ip_hdrlen(skb);
	192	struct gre_base_hdr *greh;
	193	__be32 *options;
	194	int hdr_len;
	195
	196	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr))))
	197	return -EINVAL;
	198
	199	greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
	200	if (unlikely(greh->flags & (GRE_VERSION \| GRE_ROUTING)))
	201	return -EINVAL;
	202
	203	tpi->flags = gre_flags_to_tnl_flags(greh->flags);
	204	hdr_len = ip_gre_calc_hlen(tpi->flags);
	205
	206	if (!pskb_may_pull(skb, hdr_len))
	207	return -EINVAL;
	208
	209	greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen);
	210	tpi->proto = greh->protocol;
	211
	212	options = (__be32 *)(greh + 1);
	213	if (greh->flags & GRE_CSUM) {
	214	if (check_checksum(skb)) {
	215	*csum_err = true;
	216	return -EINVAL;
	217	}
	218	options++;
	219	}
	220
	221	if (greh->flags & GRE_KEY) {
	222	tpi->key = *options;
	223	options++;
	224	} else
	225	tpi->key = 0;
	226
	227	if (unlikely(greh->flags & GRE_SEQ)) {
	228	tpi->seq = *options;
	229	options++;
	230	} else
	231	tpi->seq = 0;
	232
	233	/* WCCP version 1 and 2 protocol decoding.
	234	* - Change protocol to IP
	235	* - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
	236	*/
	237	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
	238	tpi->proto = htons(ETH_P_IP);
	239	if (((u8 )options & 0xF0) != 0x40) {
	240	hdr_len += 4;
	241	if (!pskb_may_pull(skb, hdr_len))
	242	return -EINVAL;
	243	}
	244	}
	245
	246	return iptunnel_pull_header(skb, hdr_len, tpi->proto);
	247	}
	248
9a27329d	249	static struct gre_cisco_protocol __rcu *gre_cisco_proto;
5ebaf571 PS	250	static int gre_cisco_rcv(struct sk_buff *skb)
	251	{
	252	struct tnl_ptk_info tpi;
	253	bool csum_err = false;
	254	struct gre_cisco_protocol *proto;
	255
	256	rcu_read_lock();
	257	proto = rcu_dereference(gre_cisco_proto);
	258	if (!proto)
	259	goto drop;
	260
	261	if (parse_gre_header(skb, &tpi, &csum_err) < 0)
	262	goto drop;
	263	proto->handler(skb, &tpi);
	264	rcu_read_unlock();
	265	return 0;
	266
	267	drop:
	268	rcu_read_unlock();
	269	kfree_skb(skb);
	270	return 0;
	271	}
	272
	273	static const struct gre_protocol ipgre_protocol = {
	274	.handler = gre_cisco_rcv,
	275	};
	276
bedf02f4	277	int rpl_gre_cisco_register(struct gre_cisco_protocol *newp)
5ebaf571	278	{
cc1d0dea	279	int err;
5ebaf571	280
cc1d0dea PS	281	err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
	282	if (err) {
	283	pr_warn("%s: cannot register gre_cisco protocol handler\n", __func__);
	284	return err;
	285	}
	286
	287
	288	return (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, NULL, newp) == NULL) ?
5ebaf571 PS	289	0 : -EBUSY;
5ebaf571 PS	290	}
bedf02f4	291	EXPORT_SYMBOL_GPL(rpl_gre_cisco_register);
5ebaf571	292
bedf02f4	293	int rpl_gre_cisco_unregister(struct gre_cisco_protocol *proto)
5ebaf571 PS	294	{
	295	int ret;
	296
cc1d0dea PS	297	ret = (cmpxchg((struct gre_cisco_protocol **)&gre_cisco_proto, proto, NULL) == proto) ?
cc1d0dea PS	298	0 : -EINVAL;
5ebaf571 PS	299
	300	if (ret)
	301	return ret;
	302
	303	synchronize_net();
cc1d0dea PS	304	ret = gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
cc1d0dea PS	305	return ret;
5ebaf571	306	}
bedf02f4	307	EXPORT_SYMBOL_GPL(rpl_gre_cisco_unregister);
5ebaf571	308
cc1d0dea	309	#endif /* !HAVE_GRE_CISCO_REGISTER */
9b928914	310	#endif
9b928914 PS	311
9b928914 PS	312	#endif /* CONFIG_NET_IPGRE_DEMUX */
e23775f2	313	#endif /* HAVE_METADATA_DST */