[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 void gre_build_header(const struct vport *vport,
			     const struct tnl_mutable_config *mutable,
			     void *header)
{
	struct gre_base_hdr *greh = header;
	__be32 *options = (__be32 *)(greh + 1);

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

	if (mutable->port_config.flags & TNL_F_CSUM) {
		greh->flags |= GRE_CSUM;
		*options = 0;
		options++;
	}

	if (mutable->port_config.out_key ||
	    mutable->port_config.flags & TNL_F_OUT_KEY_ACTION)
		greh->flags |= GRE_KEY;

	if (mutable->port_config.out_key)
		*options = mutable->port_config.out_key;
}

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

	/* Work backwards over the options so the checksum is last. */
	if (mutable->port_config.flags & TNL_F_OUT_KEY_ACTION) {
		*options = OVS_CB(skb)->tun_id;
		options--;
	}

	if (mutable->port_config.flags & TNL_F_CSUM)
		*(__sum16 *)options = csum_fold(skb_checksum(skb,
						skb_transport_offset(skb),
						skb->len - skb_transport_offset(skb),
						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,
	.update_header	= gre_update_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");

	return err;
}

static void gre_exit(void)
{
	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
842cf6f4 JG	53	static void gre_build_header(const struct vport *vport,
	54	const struct tnl_mutable_config *mutable,
	55	void *header)
2736b84e	56	{
842cf6f4 JG	57	struct gre_base_hdr *greh = header;
842cf6f4 JG	58	__be32 options = (__be32 )(greh + 1);
2736b84e	59
27b6cec0 JG	60	greh->protocol = htons(ETH_P_TEB);
27b6cec0 JG	61	greh->flags = 0;
2736b84e	62
842cf6f4 JG	63	if (mutable->port_config.flags & TNL_F_CSUM) {
	64	greh->flags \|= GRE_CSUM;
	65	*options = 0;
	66	options++;
	67	}
	68
2736b84e	69	if (mutable->port_config.out_key \|\|
842cf6f4	70	mutable->port_config.flags & TNL_F_OUT_KEY_ACTION)
27b6cec0	71	greh->flags \|= GRE_KEY;
2736b84e	72
842cf6f4 JG	73	if (mutable->port_config.out_key)
	74	*options = mutable->port_config.out_key;
	75	}
	76
	77	static struct sk_buff gre_update_header(const struct vport vport,
	78	const struct tnl_mutable_config *mutable,
	79	struct dst_entry *dst,
	80	struct sk_buff *skb)
	81	{
	82	__be32 options = (__be32 )(skb_network_header(skb) + mutable->tunnel_hlen
	83	- GRE_HEADER_SECTION);
2736b84e	84
842cf6f4 JG	85	/* Work backwards over the options so the checksum is last. */
	86	if (mutable->port_config.flags & TNL_F_OUT_KEY_ACTION) {
	87	*options = OVS_CB(skb)->tun_id;
2736b84e JG	88	options--;
	89	}
	90
842cf6f4	91	if (mutable->port_config.flags & TNL_F_CSUM)
2736b84e	92	(__sum16 )options = csum_fold(skb_checksum(skb,
842cf6f4 JG	93	skb_transport_offset(skb),
842cf6f4 JG	94	skb->len - skb_transport_offset(skb),
2736b84e	95	0));
5214f5c4 JG	96	/*
	97	* Allow our local IP stack to fragment the outer packet even if the
	98	* DF bit is set as a last resort.
	99	*/
	100	skb->local_df = 1;
	101
	102	return skb;
2736b84e JG	103	}
2736b84e JG	104
d1eb60cc	105	static int parse_header(struct iphdr iph, __be16 flags, __be32 *key)
2736b84e	106	{
eea2aafb	107	/* IP and ICMP protocol handlers check that the IHL is valid. */
27b6cec0 JG	108	struct gre_base_hdr greh = (struct gre_base_hdr )((u8 *)iph + (iph->ihl << 2));
27b6cec0 JG	109	__be32 options = (__be32 )(greh + 1);
2736b84e JG	110	int hdr_len;
2736b84e JG	111
27b6cec0	112	*flags = greh->flags;
2736b84e	113
d1eb60cc	114	if (unlikely(greh->flags & (GRE_VERSION \| GRE_ROUTING)))
2736b84e JG	115	return -EINVAL;
2736b84e JG	116
d1eb60cc	117	if (unlikely(greh->protocol != htons(ETH_P_TEB)))
2736b84e JG	118	return -EINVAL;
	119
	120	hdr_len = GRE_HEADER_SECTION;
	121
27b6cec0	122	if (greh->flags & GRE_CSUM) {
2736b84e JG	123	hdr_len += GRE_HEADER_SECTION;
	124	options++;
	125	}
	126
27b6cec0	127	if (greh->flags & GRE_KEY) {
2736b84e JG	128	hdr_len += GRE_HEADER_SECTION;
	129
	130	key = options;
	131	options++;
	132	} else
	133	*key = 0;
	134
d1eb60cc	135	if (unlikely(greh->flags & GRE_SEQ))
2736b84e JG	136	hdr_len += GRE_HEADER_SECTION;
	137
	138	return hdr_len;
	139	}
	140
d1eb60cc	141	/* Called with rcu_read_lock and BH disabled. */
fceb2a5b	142	static void gre_err(struct sk_buff *skb, u32 info)
2736b84e JG	143	{
2736b84e JG	144	struct vport *vport;
d1eb60cc	145	const struct tnl_mutable_config *mutable;
2736b84e JG	146	const int type = icmp_hdr(skb)->type;
	147	const int code = icmp_hdr(skb)->code;
	148	int mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
	149
	150	struct iphdr *iph;
	151	__be16 flags;
	152	__be32 key;
	153	int tunnel_hdr_len, tot_hdr_len;
	154	unsigned int orig_mac_header;
	155	unsigned int orig_nw_header;
	156
	157	if (type != ICMP_DEST_UNREACH \|\| code != ICMP_FRAG_NEEDED)
	158	return;
	159
d1eb60cc JG	160	/*
d1eb60cc JG	161	* The mimimum size packet that we would actually be able to process:
2736b84e	162	* encapsulating IP header, minimum GRE header, Ethernet header,
d1eb60cc JG	163	* inner IPv4 header.
d1eb60cc JG	164	*/
2736b84e JG	165	if (!pskb_may_pull(skb, sizeof(struct iphdr) + GRE_HEADER_SECTION +
	166	ETH_HLEN + sizeof(struct iphdr)))
	167	return;
	168
	169	iph = (struct iphdr *)skb->data;
	170
d1eb60cc	171	tunnel_hdr_len = parse_header(iph, &flags, &key);
2736b84e JG	172	if (tunnel_hdr_len < 0)
	173	return;
	174
d1eb60cc JG	175	vport = tnl_find_port(iph->saddr, iph->daddr, key,
d1eb60cc JG	176	TNL_T_PROTO_GRE \| TNL_T_KEY_EITHER, &mutable);
2736b84e JG	177	if (!vport)
	178	return;
	179
d1eb60cc JG	180	/*
d1eb60cc JG	181	* Packets received by this function were previously sent by us, so
eea2aafb JG	182	* any comparisons should be to the output values, not the input.
	183	* However, it's not really worth it to have a hash table based on
	184	* output keys (especially since ICMP error handling of tunneled packets
	185	* isn't that reliable anyways). Therefore, we do a lookup based on the
	186	* out key as if it were the in key and then check to see if the input
d1eb60cc JG	187	* and output keys are the same.
d1eb60cc JG	188	*/
eea2aafb JG	189	if (mutable->port_config.in_key != mutable->port_config.out_key)
	190	return;
	191
d1eb60cc JG	192	if (!!(mutable->port_config.flags & TNL_F_IN_KEY_MATCH) !=
d1eb60cc JG	193	!!(mutable->port_config.flags & TNL_F_OUT_KEY_ACTION))
eea2aafb JG	194	return;
eea2aafb JG	195
d1eb60cc	196	if ((mutable->port_config.flags & TNL_F_CSUM) && !(flags & GRE_CSUM))
2736b84e JG	197	return;
2736b84e JG	198
eea2aafb	199	tunnel_hdr_len += iph->ihl << 2;
2736b84e JG	200
	201	orig_mac_header = skb_mac_header(skb) - skb->data;
	202	orig_nw_header = skb_network_header(skb) - skb->data;
eea2aafb	203	skb_set_mac_header(skb, tunnel_hdr_len);
2736b84e	204
eea2aafb	205	tot_hdr_len = tunnel_hdr_len + ETH_HLEN;
2736b84e JG	206
	207	skb->protocol = eth_hdr(skb)->h_proto;
	208	if (skb->protocol == htons(ETH_P_8021Q)) {
	209	tot_hdr_len += VLAN_HLEN;
	210	skb->protocol = vlan_eth_hdr(skb)->h_vlan_encapsulated_proto;
	211	}
	212
eea2aafb JG	213	skb_set_network_header(skb, tot_hdr_len);
	214	mtu -= tot_hdr_len;
	215
2736b84e JG	216	if (skb->protocol == htons(ETH_P_IP))
2736b84e JG	217	tot_hdr_len += sizeof(struct iphdr);
6f470982	218	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
eea2aafb	219	else if (skb->protocol == htons(ETH_P_IPV6))
2736b84e	220	tot_hdr_len += sizeof(struct ipv6hdr);
6f470982	221	#endif
2736b84e JG	222	else
	223	goto out;
	224
	225	if (!pskb_may_pull(skb, tot_hdr_len))
	226	goto out;
	227
2736b84e JG	228	if (skb->protocol == htons(ETH_P_IP)) {
	229	if (mtu < IP_MIN_MTU) {
	230	if (ntohs(ip_hdr(skb)->tot_len) >= IP_MIN_MTU)
	231	mtu = IP_MIN_MTU;
	232	else
	233	goto out;
	234	}
	235
6f470982 JG	236	}
	237	#if defined(CONFIG_IPV6) \|\| defined(CONFIG_IPV6_MODULE)
	238	else if (skb->protocol == htons(ETH_P_IPV6)) {
2736b84e JG	239	if (mtu < IPV6_MIN_MTU) {
	240	unsigned int packet_length = sizeof(struct ipv6hdr) +
	241	ntohs(ipv6_hdr(skb)->payload_len);
	242
	243	if (packet_length >= IPV6_MIN_MTU
	244	\|\| ntohs(ipv6_hdr(skb)->payload_len) == 0)
	245	mtu = IPV6_MIN_MTU;
	246	else
	247	goto out;
	248	}
	249	}
6f470982	250	#endif
2736b84e	251
d1eb60cc JG	252	__skb_pull(skb, tunnel_hdr_len);
	253	tnl_frag_needed(vport, mutable, skb, mtu, key);
	254	__skb_push(skb, tunnel_hdr_len);
2736b84e JG	255
	256	out:
	257	skb_set_mac_header(skb, orig_mac_header);
	258	skb_set_network_header(skb, orig_nw_header);
	259	skb->protocol = htons(ETH_P_IP);
	260	}
	261
d1eb60cc JG	262	static bool check_checksum(struct sk_buff *skb)
	263	{
	264	struct iphdr *iph = ip_hdr(skb);
	265	struct gre_base_hdr greh = (struct gre_base_hdr )(iph + 1);
	266	__sum16 csum = 0;
	267
	268	if (greh->flags & GRE_CSUM) {
	269	switch (skb->ip_summed) {
	270	case CHECKSUM_COMPLETE:
	271	csum = csum_fold(skb->csum);
	272
	273	if (!csum)
	274	break;
	275	/* Fall through. */
	276
	277	case CHECKSUM_NONE:
	278	skb->csum = 0;
	279	csum = __skb_checksum_complete(skb);
	280	skb->ip_summed = CHECKSUM_COMPLETE;
	281	break;
	282	}
	283	}
	284
	285	return (csum == 0);
	286	}
	287
	288	/* Called with rcu_read_lock and BH disabled. */
fceb2a5b	289	static int gre_rcv(struct sk_buff *skb)
2736b84e JG	290	{
2736b84e JG	291	struct vport *vport;
d1eb60cc	292	const struct tnl_mutable_config *mutable;
2736b84e JG	293	int hdr_len;
	294	struct iphdr *iph;
	295	__be16 flags;
	296	__be32 key;
	297
d1eb60cc	298	if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr) + ETH_HLEN)))
2736b84e JG	299	goto error;
2736b84e JG	300
d1eb60cc	301	if (unlikely(!check_checksum(skb)))
2736b84e JG	302	goto error;
2736b84e JG	303
d1eb60cc JG	304	hdr_len = parse_header(ip_hdr(skb), &flags, &key);
d1eb60cc JG	305	if (unlikely(hdr_len < 0))
2736b84e JG	306	goto error;
2736b84e JG	307
d1eb60cc	308	if (unlikely(!pskb_may_pull(skb, hdr_len + ETH_HLEN)))
2736b84e	309	goto error;
2736b84e	310
d1eb60cc JG	311	iph = ip_hdr(skb);
	312	vport = tnl_find_port(iph->daddr, iph->saddr, key,
	313	TNL_T_PROTO_GRE \| TNL_T_KEY_EITHER, &mutable);
	314	if (unlikely(!vport)) {
	315	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
2736b84e JG	316	goto error;
	317	}
	318
d1eb60cc	319	if (mutable->port_config.flags & TNL_F_IN_KEY_MATCH)
2736b84e JG	320	OVS_CB(skb)->tun_id = key;
	321	else
	322	OVS_CB(skb)->tun_id = 0;
	323
d1eb60cc JG	324	__skb_pull(skb, hdr_len);
d1eb60cc JG	325	skb_postpull_rcsum(skb, skb_transport_header(skb), hdr_len + ETH_HLEN);
2736b84e	326
d1eb60cc	327	tnl_rcv(vport, skb);
2736b84e JG	328	return 0;
	329
	330	error:
	331	kfree_skb(skb);
	332	return 0;
	333	}
	334
d1eb60cc JG	335	struct tnl_ops gre_tnl_ops = {
	336	.tunnel_type = TNL_T_PROTO_GRE,
	337	.ipproto = IPPROTO_GRE,
	338	.hdr_len = gre_hdr_len,
	339	.build_header = gre_build_header,
842cf6f4	340	.update_header = gre_update_header,
d1eb60cc	341	};
2736b84e	342
d1eb60cc	343	static struct vport gre_create(const char name, const void __user *config)
2736b84e	344	{
d1eb60cc	345	return tnl_create(name, config, &gre_vport_ops, &gre_tnl_ops);
2736b84e JG	346	}
	347
	348	static struct net_protocol gre_protocol_handlers = {
	349	.handler = gre_rcv,
	350	.err_handler = gre_err,
	351	};
	352
fceb2a5b	353	static int gre_init(void)
2736b84e JG	354	{
	355	int err;
	356
	357	err = inet_add_protocol(&gre_protocol_handlers, IPPROTO_GRE);
842cf6f4	358	if (err)
dfffaef1	359	pr_warn("cannot register gre protocol handler\n");
2736b84e	360
2736b84e JG	361	return err;
	362	}
	363
d1eb60cc	364	static void gre_exit(void)
2736b84e	365	{
d1eb60cc	366	inet_del_protocol(&gre_protocol_handlers, IPPROTO_GRE);
2736b84e JG	367	}
	368
	369	struct vport_ops gre_vport_ops = {
	370	.type = "gre",
	371	.flags = VPORT_F_GEN_STATS \| VPORT_F_TUN_ID,
	372	.init = gre_init,
	373	.exit = gre_exit,
	374	.create = gre_create,
d1eb60cc JG	375	.modify = tnl_modify,
	376	.destroy = tnl_destroy,
	377	.set_mtu = tnl_set_mtu,
	378	.set_addr = tnl_set_addr,
	379	.get_name = tnl_get_name,
	380	.get_addr = tnl_get_addr,
b19e8815 JG	381	.get_dev_flags = vport_gen_get_dev_flags,
	382	.is_running = vport_gen_is_running,
	383	.get_operstate = vport_gen_get_operstate,
d1eb60cc JG	384	.get_mtu = tnl_get_mtu,
d1eb60cc JG	385	.send = tnl_send,
2736b84e	386	};