[mirror_ovs.git] / datapath / vport-gre.c

/*
 * Copyright (c) 2010 Nicira Networks.
 * Distributed under the terms of the GNU GPL version 2.
 *
 * Significant portions of this file may be copied from parts of the Linux
 * kernel, by Linus Torvalds and others.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/if.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/if_tunnel.h>
#include <linux/if_vlan.h>
#include <linux/in.h>

#include <net/icmp.h>
#include <net/ip.h>
#include <net/protocol.h>

#include "tunnel.h"
#include "vport.h"
#include "vport-generic.h"

/*
 * The GRE header is composed of a series of sections: a base and then a variable
 * number of options.
 */
#define GRE_HEADER_SECTION 4

struct gre_base_hdr {
	__be16 flags;
	__be16 protocol;
};

static int gre_hdr_len(const struct tnl_port_config *port_config)
{
	int len;

	len = GRE_HEADER_SECTION;

	if (port_config->flags & TNL_F_CSUM)
		len += GRE_HEADER_SECTION;

	if (port_config->out_key ||
	    port_config->flags & TNL_F_OUT_KEY_ACTION)
		len += GRE_HEADER_SECTION;

	return len;
}

static struct sk_buff *gre_build_header(struct sk_buff *skb,
					const struct vport *vport,
					const struct tnl_mutable_config *mutable,
					struct dst_entry *dst)
{
	struct gre_base_hdr *greh = (struct gre_base_hdr *)skb_transport_header(skb);
	__be32 *options = (__be32 *)(skb_network_header(skb) + mutable->tunnel_hlen
					       - GRE_HEADER_SECTION);

	greh->protocol = htons(ETH_P_TEB);
	greh->flags = 0;

	/* Work backwards over the options so the checksum is last. */
	if (mutable->port_config.out_key ||
	    mutable->port_config.flags & TNL_F_OUT_KEY_ACTION) {
		greh->flags |= GRE_KEY;

		if (mutable->port_config.flags & TNL_F_OUT_KEY_ACTION)
			*options = OVS_CB(skb)->tun_id;
		else
			*options = mutable->port_config.out_key;

		options--;
	}

	if (mutable->port_config.flags & TNL_F_CSUM) {
		greh->flags |= GRE_CSUM;

		*options = 0;
		*(__sum16 *)options = csum_fold(skb_checksum(skb,
						sizeof(struct iphdr),
						skb->len - sizeof(struct iphdr),
						0));
	}

	/*
	 * Allow our local IP stack to fragment the outer packet even if the
	 * DF bit is set as a last resort.
	 */
	skb->local_df = 1;

	return skb;
}

static int parse_header(struct iphdr *iph, __be16 *flags, __be32 *key)
{
	/* IP and ICMP protocol handlers check that the IHL is valid. */
	struct gre_base_hdr *greh = (struct gre_base_hdr *)((u8 *)iph + (iph->ihl << 2));
	__be32 *options = (__be32 *)(greh + 1);
	int hdr_len;

	*flags = greh->flags;

	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
		return -EINVAL;

	if (unlikely(greh->protocol != htons(ETH_P_TEB)))
		return -EINVAL;

	hdr_len = GRE_HEADER_SECTION;

	if (greh->flags & GRE_CSUM) {
		hdr_len += GRE_HEADER_SECTION;
		options++;
	}

	if (greh->flags & GRE_KEY) {
		hdr_len += GRE_HEADER_SECTION;

		*key = *options;
		options++;
	} else
		*key = 0;

	if (unlikely(greh->flags & GRE_SEQ))
		hdr_len += GRE_HEADER_SECTION;

	return hdr_len;
}

/* Called with rcu_read_lock and BH disabled. */
static void gre_err(struct sk_buff *skb, u32 info)
{
	struct vport *vport;
	const struct tnl_mutable_config *mutable;
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	int mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);

	struct iphdr *iph;
	__be16 flags;
	__be32 key;
	int tunnel_hdr_len, tot_hdr_len;
	unsigned int orig_mac_header;
	unsigned int orig_nw_header;

	if (type != ICMP_DEST_UNREACH || code != ICMP_FRAG_NEEDED)
		return;

	/*
	 * The mimimum size packet that we would actually be able to process:
	 * encapsulating IP header, minimum GRE header, Ethernet header,
	 * inner IPv4 header.
	 */
	if (!pskb_may_pull(skb, sizeof(struct iphdr) + GRE_HEADER_SECTION +
				ETH_HLEN + sizeof(struct iphdr)))
		return;

	iph = (struct iphdr *)skb->data;

	tunnel_hdr_len = parse_header(iph, &flags, &key);
	if (tunnel_hdr_len < 0)
		return;

	vport = tnl_find_port(iph->saddr, iph->daddr, key,
			      TNL_T_PROTO_GRE | TNL_T_KEY_EITHER, &mutable);
	if (!vport)
		return;

	/*
	 * Packets received by this function were previously sent by us, so
	 * any comparisons should be to the output values, not the input.
	 * However, it's not really worth it to have a hash table based on
	 * output keys (especially since ICMP error handling of tunneled packets
	 * isn't that reliable anyways).  Therefore, we do a lookup based on the
	 * out key as if it were the in key and then check to see if the input
	 * and output keys are the same.
	 */
	if (mutable->port_config.in_key != mutable->port_config.out_key)
		return;

	if (!!(mutable->port_config.flags & TNL_F_IN_KEY_MATCH) !=
	    !!(mutable->port_config.flags & TNL_F_OUT_KEY_ACTION))
		return;

	if ((mutable->port_config.flags & TNL_F_CSUM) && !(flags & GRE_CSUM))
		return;

	tunnel_hdr_len += iph->ihl << 2;

	orig_mac_header = skb_mac_header(skb) - skb->data;
	orig_nw_header = skb_network_header(skb) - skb->data;
	skb_set_mac_header(skb, tunnel_hdr_len);

	tot_hdr_len = tunnel_hdr_len + ETH_HLEN;

	skb->protocol = eth_hdr(skb)->h_proto;
	if (skb->protocol == htons(ETH_P_8021Q)) {
		tot_hdr_len += VLAN_HLEN;
		skb->protocol = vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
	}

	skb_set_network_header(skb, tot_hdr_len);
	mtu -= tot_hdr_len;

	if (skb->protocol == htons(ETH_P_IP))
		tot_hdr_len += sizeof(struct iphdr);
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	else if (skb->protocol == htons(ETH_P_IPV6))
		tot_hdr_len += sizeof(struct ipv6hdr);
#endif
	else
		goto out;

	if (!pskb_may_pull(skb, tot_hdr_len))
		goto out;

	if (skb->protocol == htons(ETH_P_IP)) {
		if (mtu < IP_MIN_MTU) {
			if (ntohs(ip_hdr(skb)->tot_len) >= IP_MIN_MTU)
				mtu = IP_MIN_MTU;
			else
				goto out;
		}

	}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
	else if (skb->protocol == htons(ETH_P_IPV6)) {
		if (mtu < IPV6_MIN_MTU) {
			unsigned int packet_length = sizeof(struct ipv6hdr) +
					      ntohs(ipv6_hdr(skb)->payload_len);

			if (packet_length >= IPV6_MIN_MTU
			    || ntohs(ipv6_hdr(skb)->payload_len) == 0)
				mtu = IPV6_MIN_MTU;
			else
				goto out;
		}
	}
#endif

	__skb_pull(skb, tunnel_hdr_len);
	tnl_frag_needed(vport, mutable, skb, mtu, key);
	__skb_push(skb, tunnel_hdr_len);

out:
	skb_set_mac_header(skb, orig_mac_header);
	skb_set_network_header(skb, orig_nw_header);
	skb->protocol = htons(ETH_P_IP);
}

static bool check_checksum(struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);
	struct gre_base_hdr *greh = (struct gre_base_hdr *)(iph + 1);
	__sum16 csum = 0;

	if (greh->flags & GRE_CSUM) {
		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 == 0);
}

/* Called with rcu_read_lock and BH disabled. */
static int gre_rcv(struct sk_buff *skb)
{
	struct vport *vport;
	const struct tnl_mutable_config *mutable;
	int hdr_len;
	struct iphdr *iph;
	__be16 flags;
	__be32 key;

	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr) + ETH_HLEN)))
		goto error;

	if (unlikely(!check_checksum(skb)))
		goto error;

	hdr_len = parse_header(ip_hdr(skb), &flags, &key);
	if (unlikely(hdr_len < 0))
		goto error;

	if (unlikely(!pskb_may_pull(skb, hdr_len + ETH_HLEN)))
		goto error;

	iph = ip_hdr(skb);
	vport = tnl_find_port(iph->daddr, iph->saddr, key,
			      TNL_T_PROTO_GRE | TNL_T_KEY_EITHER, &mutable);
	if (unlikely(!vport)) {
		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
		goto error;
	}

	if (mutable->port_config.flags & TNL_F_IN_KEY_MATCH)
		OVS_CB(skb)->tun_id = key;
	else
		OVS_CB(skb)->tun_id = 0;

	__skb_pull(skb, hdr_len);
	skb_postpull_rcsum(skb, skb_transport_header(skb), hdr_len + ETH_HLEN);

	tnl_rcv(vport, skb);
	return 0;

error:
	kfree_skb(skb);
	return 0;
}

struct tnl_ops gre_tnl_ops = {
	.tunnel_type	= TNL_T_PROTO_GRE,
	.ipproto	= IPPROTO_GRE,
	.hdr_len	= gre_hdr_len,
	.build_header	= gre_build_header,
};

static struct vport *gre_create(const char *name, const void __user *config)
{
	return tnl_create(name, config, &gre_vport_ops, &gre_tnl_ops);
}

static struct net_protocol gre_protocol_handlers = {
	.handler	=	gre_rcv,
	.err_handler	=	gre_err,
};

static int gre_init(void)
{
	int err;

	err = inet_add_protocol(&gre_protocol_handlers, IPPROTO_GRE);
	if (err) {
		pr_warn("cannot register gre protocol handler\n");
		goto out;
	}

	err = tnl_init();

out:
	return err;
}

static void gre_exit(void)
{
	tnl_exit();
	inet_del_protocol(&gre_protocol_handlers, IPPROTO_GRE);
}

struct vport_ops gre_vport_ops = {
	.type		= "gre",
	.flags		= VPORT_F_GEN_STATS | VPORT_F_TUN_ID,
	.init		= gre_init,
	.exit		= gre_exit,
	.create		= gre_create,
	.modify		= tnl_modify,
	.destroy	= tnl_destroy,
	.set_mtu	= tnl_set_mtu,
	.set_addr	= tnl_set_addr,
	.get_name	= tnl_get_name,
	.get_addr	= tnl_get_addr,
	.get_dev_flags	= vport_gen_get_dev_flags,
	.is_running	= vport_gen_is_running,
	.get_operstate	= vport_gen_get_operstate,
	.get_mtu	= tnl_get_mtu,
	.send		= tnl_send,
};
Commit	Line	Data
2736b84e JG	1	/*
	2	* Copyright (c) 2010 Nicira Networks.
	3	* Distributed under the terms of the GNU GPL version 2.
	4	*
	5	* Significant portions of this file may be copied from parts of the Linux
	6	* kernel, by Linus Torvalds and others.
	7	*/
	8
dfffaef1 JP	9	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
dfffaef1 JP	10
d1eb60cc JG	11	#include <linux/if.h>
d1eb60cc JG	12	#include <linux/skbuff.h>
2736b84e JG	13	#include <linux/ip.h>
	14	#include <linux/if_tunnel.h>
	15	#include <linux/if_vlan.h>
	16	#include <linux/in.h>
2736b84e	17
2736b84e	18	#include <net/icmp.h>
2736b84e	19	#include <net/ip.h>
2736b84e	20	#include <net/protocol.h>
2736b84e	21
d1eb60cc	22	#include "tunnel.h"
2736b84e	23	#include "vport.h"
b19e8815	24	#include "vport-generic.h"
2736b84e	25
d1eb60cc JG	26	/*
	27	* The GRE header is composed of a series of sections: a base and then a variable
	28	* number of options.
	29	*/
2736b84e JG	30	#define GRE_HEADER_SECTION 4
2736b84e JG	31
27b6cec0 JG	32	struct gre_base_hdr {
	33	__be16 flags;
	34	__be16 protocol;
	35	};
	36
d1eb60cc	37	static int gre_hdr_len(const struct tnl_port_config *port_config)
2736b84e	38	{
d1eb60cc	39	int len;
2736b84e	40
d1eb60cc	41	len = GRE_HEADER_SECTION;
2736b84e	42
d1eb60cc JG	43	if (port_config->flags & TNL_F_CSUM)
d1eb60cc JG	44	len += GRE_HEADER_SECTION;
2736b84e	45
d1eb60cc JG	46	if (port_config->out_key \|\|
	47	port_config->flags & TNL_F_OUT_KEY_ACTION)
	48	len += GRE_HEADER_SECTION;
2736b84e	49
d1eb60cc	50	return len;
2736b84e JG	51	}
2736b84e JG	52
5214f5c4 JG	53	static struct sk_buff gre_build_header(struct sk_buff skb,
	54	const struct vport *vport,
	55	const struct tnl_mutable_config *mutable,
	56	struct dst_entry *dst)
2736b84e	57	{
d1eb60cc JG	58	struct gre_base_hdr greh = (struct gre_base_hdr )skb_transport_header(skb);
d1eb60cc JG	59	__be32 options = (__be32 )(skb_network_header(skb) + mutable->tunnel_hlen
2736b84e JG	60	- GRE_HEADER_SECTION);
2736b84e JG	61
27b6cec0 JG	62	greh->protocol = htons(ETH_P_TEB);
27b6cec0 JG	63	greh->flags = 0;
2736b84e JG	64
	65	/* Work backwards over the options so the checksum is last. */
	66	if (mutable->port_config.out_key \|\|
d1eb60cc	67	mutable->port_config.flags & TNL_F_OUT_KEY_ACTION) {
27b6cec0	68	greh->flags \|= GRE_KEY;
2736b84e	69
d1eb60cc	70	if (mutable->port_config.flags & TNL_F_OUT_KEY_ACTION)
2736b84e JG	71	*options = OVS_CB(skb)->tun_id;
	72	else
	73	*options = mutable->port_config.out_key;
	74
	75	options--;
	76	}
	77
d1eb60cc	78	if (mutable->port_config.flags & TNL_F_CSUM) {
27b6cec0	79	greh->flags \|= GRE_CSUM;
2736b84e JG	80
	81	*options = 0;
	82	(__sum16 )options = csum_fold(skb_checksum(skb,
	83	sizeof(struct iphdr),
	84	skb->len - sizeof(struct iphdr),
	85	0));
	86	}
5214f5c4 JG	87
	88	/*
	89	* Allow our local IP stack to fragment the outer packet even if the
	90	* DF bit is set as a last resort.
	91	*/
	92	skb->local_df = 1;
	93
	94	return skb;
2736b84e JG	95	}
2736b84e JG	96
d1eb60cc	97	static int parse_header(struct iphdr iph, __be16 flags, __be32 *key)
2736b84e	98	{
eea2aafb	99	/* IP and ICMP protocol handlers check that the IHL is valid. */
27b6cec0 JG	100	struct gre_base_hdr greh = (struct gre_base_hdr )((u8 *)iph + (iph->ihl << 2));
27b6cec0 JG	101	__be32 options = (__be32 )(greh + 1);
2736b84e JG	102	int hdr_len;
2736b84e JG	103
27b6cec0	104	*flags = greh->flags;
2736b84e	105
d1eb60cc	106	if (unlikely(greh->flags & (GRE_VERSION \| GRE_ROUTING)))
2736b84e JG	107	return -EINVAL;
2736b84e JG	108
d1eb60cc	109	if (unlikely(greh->protocol != htons(ETH_P_TEB)))
2736b84e JG	110	return -EINVAL;
	111
	112	hdr_len = GRE_HEADER_SECTION;
	113
27b6cec0	114	if (greh->flags & GRE_CSUM) {
2736b84e JG	115	hdr_len += GRE_HEADER_SECTION;
	116	options++;
	117	}
	118
27b6cec0	119	if (greh->flags & GRE_KEY) {
2736b84e JG	120	hdr_len += GRE_HEADER_SECTION;
	121
	122	key = options;
	123	options++;
	124	} else
	125	*key = 0;
	126
d1eb60cc	127	if (unlikely(greh->flags & GRE_SEQ))
2736b84e JG	128	hdr_len += GRE_HEADER_SECTION;
	129
	130	return hdr_len;
	131	}
	132
d1eb60cc	133	/* Called with rcu_read_lock and BH disabled. */
fceb2a5b	134	static void gre_err(struct sk_buff *skb, u32 info)
2736b84e JG	135	{
2736b84e JG	136	struct vport *vport;
d1eb60cc	137	const struct tnl_mutable_config *mutable;
2736b84e JG	138	const int type = icmp_hdr(skb)->type;
	139	const int code = icmp_hdr(skb)->code;
	140	int mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
	141
	142	struct iphdr *iph;
	143	__be16 flags;
	144	__be32 key;
	145	int tunnel_hdr_len, tot_hdr_len;
	146	unsigned int orig_mac_header;
	147	unsigned int orig_nw_header;
	148
	149	if (type != ICMP_DEST_UNREACH \|\| code != ICMP_FRAG_NEEDED)
	150	return;
	151
d1eb60cc JG	152	/*
d1eb60cc JG	153	* The mimimum size packet that we would actually be able to process:
2736b84e	154	* encapsulating IP header, minimum GRE header, Ethernet header,
d1eb60cc JG	155	* inner IPv4 header.
d1eb60cc JG	156	*/
2736b84e JG	157	if (!pskb_may_pull(skb, sizeof(struct iphdr) + GRE_HEADER_SECTION +
	158	ETH_HLEN + sizeof(struct iphdr)))
	159	return;
	160
	161	iph = (struct iphdr *)skb->data;
	162
d1eb60cc	163	tunnel_hdr_len = parse_header(iph, &flags, &key);
2736b84e JG	164	if (tunnel_hdr_len < 0)
	165	return;
	166
d1eb60cc JG	167	vport = tnl_find_port(iph->saddr, iph->daddr, key,
d1eb60cc JG	168	TNL_T_PROTO_GRE \| TNL_T_KEY_EITHER, &mutable);
2736b84e JG	169	if (!vport)
	170	return;
	171
d1eb60cc JG	172	/*
d1eb60cc JG	173	* Packets received by this function were previously sent by us, so
eea2aafb JG	174	* any comparisons should be to the output values, not the input.
	175	* However, it's not really worth it to have a hash table based on
	176	* output keys (especially since ICMP error handling of tunneled packets
	177	* isn't that reliable anyways). Therefore, we do a lookup based on the
	178	* out key as if it were the in key and then check to see if the input
d1eb60cc JG	179	* and output keys are the same.
d1eb60cc JG	180	*/
eea2aafb JG	181	if (mutable->port_config.in_key != mutable->port_config.out_key)
	182	return;
	183
d1eb60cc JG	184	if (!!(mutable->port_config.flags & TNL_F_IN_KEY_MATCH) !=
d1eb60cc JG	185	!!(mutable->port_config.flags & TNL_F_OUT_KEY_ACTION))
eea2aafb JG	186	return;
eea2aafb JG	187
d1eb60cc	188	if ((mutable->port_config.flags & TNL_F_CSUM) && !(flags & GRE_CSUM))
2736b84e JG	189	return;
2736b84e JG	190
eea2aafb	191	tunnel_hdr_len += iph->ihl << 2;
2736b84e JG	192
	193	orig_mac_header = skb_mac_header(skb) - skb->data;
	194	orig_nw_header = skb_network_header(skb) - skb->data;
eea2aafb	195	skb_set_mac_header(skb, tunnel_hdr_len);
2736b84e	196
eea2aafb	197	tot_hdr_len = tunnel_hdr_len + ETH_HLEN;
2736b84e JG	198
	199	skb->protocol = eth_hdr(skb)->h_proto;
	200	if (skb->protocol == htons(ETH_P_8021Q)) {
	201	tot_hdr_len += VLAN_HLEN;
	202	skb->protocol = vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
	203	}
	204
eea2aafb JG	205	skb_set_network_header(skb, tot_hdr_len);
	206	mtu -= tot_hdr_len;
	207
2736b84e JG	208	if (skb->protocol == htons(ETH_P_IP))
2736b84e JG	209	tot_hdr_len += sizeof(struct iphdr);
6f470982	210	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
eea2aafb	211	else if (skb->protocol == htons(ETH_P_IPV6))
2736b84e	212	tot_hdr_len += sizeof(struct ipv6hdr);
6f470982	213	#endif
2736b84e JG	214	else
	215	goto out;
	216
	217	if (!pskb_may_pull(skb, tot_hdr_len))
	218	goto out;
	219
2736b84e JG	220	if (skb->protocol == htons(ETH_P_IP)) {
	221	if (mtu < IP_MIN_MTU) {
	222	if (ntohs(ip_hdr(skb)->tot_len) >= IP_MIN_MTU)
	223	mtu = IP_MIN_MTU;
	224	else
	225	goto out;
	226	}
	227
6f470982 JG	228	}
	229	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	230	else if (skb->protocol == htons(ETH_P_IPV6)) {
2736b84e JG	231	if (mtu < IPV6_MIN_MTU) {
	232	unsigned int packet_length = sizeof(struct ipv6hdr) +
	233	ntohs(ipv6_hdr(skb)->payload_len);
	234
	235	if (packet_length >= IPV6_MIN_MTU
	236	\|\| ntohs(ipv6_hdr(skb)->payload_len) == 0)
	237	mtu = IPV6_MIN_MTU;
	238	else
	239	goto out;
	240	}
	241	}
6f470982	242	#endif
2736b84e	243
d1eb60cc JG	244	__skb_pull(skb, tunnel_hdr_len);
	245	tnl_frag_needed(vport, mutable, skb, mtu, key);
	246	__skb_push(skb, tunnel_hdr_len);
2736b84e JG	247
	248	out:
	249	skb_set_mac_header(skb, orig_mac_header);
	250	skb_set_network_header(skb, orig_nw_header);
	251	skb->protocol = htons(ETH_P_IP);
	252	}
	253
d1eb60cc JG	254	static bool check_checksum(struct sk_buff *skb)
	255	{
	256	struct iphdr *iph = ip_hdr(skb);
	257	struct gre_base_hdr greh = (struct gre_base_hdr )(iph + 1);
	258	__sum16 csum = 0;
	259
	260	if (greh->flags & GRE_CSUM) {
	261	switch (skb->ip_summed) {
	262	case CHECKSUM_COMPLETE:
	263	csum = csum_fold(skb->csum);
	264
	265	if (!csum)
	266	break;
	267	/* Fall through. */
	268
	269	case CHECKSUM_NONE:
	270	skb->csum = 0;
	271	csum = __skb_checksum_complete(skb);
	272	skb->ip_summed = CHECKSUM_COMPLETE;
	273	break;
	274	}
	275	}
	276
	277	return (csum == 0);
	278	}
	279
	280	/* Called with rcu_read_lock and BH disabled. */
fceb2a5b	281	static int gre_rcv(struct sk_buff *skb)
2736b84e JG	282	{
2736b84e JG	283	struct vport *vport;
d1eb60cc	284	const struct tnl_mutable_config *mutable;
2736b84e JG	285	int hdr_len;
	286	struct iphdr *iph;
	287	__be16 flags;
	288	__be32 key;
	289
d1eb60cc	290	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr) + ETH_HLEN)))
2736b84e JG	291	goto error;
2736b84e JG	292
d1eb60cc	293	if (unlikely(!check_checksum(skb)))
2736b84e JG	294	goto error;
2736b84e JG	295
d1eb60cc JG	296	hdr_len = parse_header(ip_hdr(skb), &flags, &key);
d1eb60cc JG	297	if (unlikely(hdr_len < 0))
2736b84e JG	298	goto error;
2736b84e JG	299
d1eb60cc	300	if (unlikely(!pskb_may_pull(skb, hdr_len + ETH_HLEN)))
2736b84e	301	goto error;
2736b84e	302
d1eb60cc JG	303	iph = ip_hdr(skb);
	304	vport = tnl_find_port(iph->daddr, iph->saddr, key,
	305	TNL_T_PROTO_GRE \| TNL_T_KEY_EITHER, &mutable);
	306	if (unlikely(!vport)) {
	307	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
2736b84e JG	308	goto error;
	309	}
	310
d1eb60cc	311	if (mutable->port_config.flags & TNL_F_IN_KEY_MATCH)
2736b84e JG	312	OVS_CB(skb)->tun_id = key;
	313	else
	314	OVS_CB(skb)->tun_id = 0;
	315
d1eb60cc JG	316	__skb_pull(skb, hdr_len);
d1eb60cc JG	317	skb_postpull_rcsum(skb, skb_transport_header(skb), hdr_len + ETH_HLEN);
2736b84e	318
d1eb60cc	319	tnl_rcv(vport, skb);
2736b84e JG	320	return 0;
	321
	322	error:
	323	kfree_skb(skb);
	324	return 0;
	325	}
	326
d1eb60cc JG	327	struct tnl_ops gre_tnl_ops = {
	328	.tunnel_type = TNL_T_PROTO_GRE,
	329	.ipproto = IPPROTO_GRE,
	330	.hdr_len = gre_hdr_len,
	331	.build_header = gre_build_header,
	332	};
2736b84e	333
d1eb60cc	334	static struct vport gre_create(const char name, const void __user *config)
2736b84e	335	{
d1eb60cc	336	return tnl_create(name, config, &gre_vport_ops, &gre_tnl_ops);
2736b84e JG	337	}
	338
	339	static struct net_protocol gre_protocol_handlers = {
	340	.handler = gre_rcv,
	341	.err_handler = gre_err,
	342	};
	343
fceb2a5b	344	static int gre_init(void)
2736b84e JG	345	{
	346	int err;
	347
	348	err = inet_add_protocol(&gre_protocol_handlers, IPPROTO_GRE);
d1eb60cc	349	if (err) {
dfffaef1	350	pr_warn("cannot register gre protocol handler\n");
d1eb60cc	351	goto out;
2736b84e JG	352	}
2736b84e JG	353
d1eb60cc	354	err = tnl_init();
2736b84e	355
d1eb60cc	356	out:
2736b84e JG	357	return err;
	358	}
	359
d1eb60cc	360	static void gre_exit(void)
2736b84e	361	{
d1eb60cc JG	362	tnl_exit();
d1eb60cc JG	363	inet_del_protocol(&gre_protocol_handlers, IPPROTO_GRE);
2736b84e JG	364	}
	365
	366	struct vport_ops gre_vport_ops = {
	367	.type = "gre",
	368	.flags = VPORT_F_GEN_STATS \| VPORT_F_TUN_ID,
	369	.init = gre_init,
	370	.exit = gre_exit,
	371	.create = gre_create,
d1eb60cc JG	372	.modify = tnl_modify,
	373	.destroy = tnl_destroy,
	374	.set_mtu = tnl_set_mtu,
	375	.set_addr = tnl_set_addr,
	376	.get_name = tnl_get_name,
	377	.get_addr = tnl_get_addr,
b19e8815 JG	378	.get_dev_flags = vport_gen_get_dev_flags,
	379	.is_running = vport_gen_is_running,
	380	.get_operstate = vport_gen_get_operstate,
d1eb60cc JG	381	.get_mtu = tnl_get_mtu,
d1eb60cc JG	382	.send = tnl_send,
2736b84e	383	};