net/openvswitch/vport.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2007-2014 Nicira, Inc.
  */

 #include <linux/etherdevice.h>
 #include <linux/if.h>
 #include <linux/if_vlan.h>
 #include <linux/jhash.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/percpu.h>
 #include <linux/rcupdate.h>
 #include <linux/rtnetlink.h>
 #include <linux/compat.h>
 #include <net/net_namespace.h>
 #include <linux/module.h>

 #include "datapath.h"
 #include "vport.h"
 #include "vport-internal_dev.h"

 static LIST_HEAD(vport_ops_list);

 /* Protected by RCU read lock for reading, ovs_mutex for writing. */
 static struct hlist_head *dev_table;
 #define VPORT_HASH_BUCKETS 1024

 /**
  *	ovs_vport_init - initialize vport subsystem
  *
  * Called at module load time to initialize the vport subsystem.
  */
 int ovs_vport_init(void)
 {
 	dev_table = kcalloc(VPORT_HASH_BUCKETS, sizeof(struct hlist_head),
 			    GFP_KERNEL);
 	if (!dev_table)
 		return -ENOMEM;

 	return 0;
 }

 /**
  *	ovs_vport_exit - shutdown vport subsystem
  *
  * Called at module exit time to shutdown the vport subsystem.
  */
 void ovs_vport_exit(void)
 {
 	kfree(dev_table);
 }

 static struct hlist_head *hash_bucket(const struct net *net, const char *name)
 {
 	unsigned int hash = jhash(name, strlen(name), (unsigned long) net);
 	return &dev_table[hash & (VPORT_HASH_BUCKETS - 1)];
 }

 int __ovs_vport_ops_register(struct vport_ops *ops)
 {
 	int err = -EEXIST;
 	struct vport_ops *o;

 	ovs_lock();
 	list_for_each_entry(o, &vport_ops_list, list)
 		if (ops->type == o->type)
 			goto errout;

 	list_add_tail(&ops->list, &vport_ops_list);
 	err = 0;
 errout:
 	ovs_unlock();
 	return err;
 }
 EXPORT_SYMBOL_GPL(__ovs_vport_ops_register);

 void ovs_vport_ops_unregister(struct vport_ops *ops)
 {
 	ovs_lock();
 	list_del(&ops->list);
 	ovs_unlock();
 }
 EXPORT_SYMBOL_GPL(ovs_vport_ops_unregister);

 /**
  *	ovs_vport_locate - find a port that has already been created
  *
  * @net: network namespace
  * @name: name of port to find
  *
  * Must be called with ovs or RCU read lock.
  */
 struct vport *ovs_vport_locate(const struct net *net, const char *name)
 {
 	struct hlist_head *bucket = hash_bucket(net, name);
 	struct vport *vport;

 	hlist_for_each_entry_rcu(vport, bucket, hash_node,
 				 lockdep_ovsl_is_held())
 		if (!strcmp(name, ovs_vport_name(vport)) &&
 		    net_eq(ovs_dp_get_net(vport->dp), net))
 			return vport;

 	return NULL;
 }

 /**
  *	ovs_vport_alloc - allocate and initialize new vport
  *
  * @priv_size: Size of private data area to allocate.
  * @ops: vport device ops
  *
  * Allocate and initialize a new vport defined by @ops.  The vport will contain
  * a private data area of size @priv_size that can be accessed using
  * vport_priv().  vports that are no longer needed should be released with
  * vport_free().
  */
 struct vport *ovs_vport_alloc(int priv_size, const struct vport_ops *ops,
 			      const struct vport_parms *parms)
 {
 	struct vport *vport;
 	size_t alloc_size;

 	alloc_size = sizeof(struct vport);
 	if (priv_size) {
 		alloc_size = ALIGN(alloc_size, VPORT_ALIGN);
 		alloc_size += priv_size;
 	}

 	vport = kzalloc(alloc_size, GFP_KERNEL);
 	if (!vport)
 		return ERR_PTR(-ENOMEM);

 	vport->dp = parms->dp;
 	vport->port_no = parms->port_no;
 	vport->ops = ops;
 	INIT_HLIST_NODE(&vport->dp_hash_node);

 	if (ovs_vport_set_upcall_portids(vport, parms->upcall_portids)) {
 		kfree(vport);
 		return ERR_PTR(-EINVAL);
 	}

 	return vport;
 }
 EXPORT_SYMBOL_GPL(ovs_vport_alloc);

 /**
  *	ovs_vport_free - uninitialize and free vport
  *
  * @vport: vport to free
  *
  * Frees a vport allocated with vport_alloc() when it is no longer needed.
  *
  * The caller must ensure that an RCU grace period has passed since the last
  * time @vport was in a datapath.
  */
 void ovs_vport_free(struct vport *vport)
 {
 	/* vport is freed from RCU callback or error path, Therefore
 	 * it is safe to use raw dereference.
 	 */
 	kfree(rcu_dereference_raw(vport->upcall_portids));
 	kfree(vport);
 }
 EXPORT_SYMBOL_GPL(ovs_vport_free);

 static struct vport_ops *ovs_vport_lookup(const struct vport_parms *parms)
 {
 	struct vport_ops *ops;

 	list_for_each_entry(ops, &vport_ops_list, list)
 		if (ops->type == parms->type)
 			return ops;

 	return NULL;
 }

 /**
  *	ovs_vport_add - add vport device (for kernel callers)
  *
  * @parms: Information about new vport.
  *
  * Creates a new vport with the specified configuration (which is dependent on
  * device type).  ovs_mutex must be held.
  */
 struct vport *ovs_vport_add(const struct vport_parms *parms)
 {
 	struct vport_ops *ops;
 	struct vport *vport;

 	ops = ovs_vport_lookup(parms);
 	if (ops) {
 		struct hlist_head *bucket;

 		if (!try_module_get(ops->owner))
 			return ERR_PTR(-EAFNOSUPPORT);

 		vport = ops->create(parms);
 		if (IS_ERR(vport)) {
 			module_put(ops->owner);
 			return vport;
 		}

 		bucket = hash_bucket(ovs_dp_get_net(vport->dp),
 				     ovs_vport_name(vport));
 		hlist_add_head_rcu(&vport->hash_node, bucket);
 		return vport;
 	}

 	/* Unlock to attempt module load and return -EAGAIN if load
 	 * was successful as we need to restart the port addition
 	 * workflow.
 	 */
 	ovs_unlock();
 	request_module("vport-type-%d", parms->type);
 	ovs_lock();

 	if (!ovs_vport_lookup(parms))
 		return ERR_PTR(-EAFNOSUPPORT);
 	else
 		return ERR_PTR(-EAGAIN);
 }

 /**
  *	ovs_vport_set_options - modify existing vport device (for kernel callers)
  *
  * @vport: vport to modify.
  * @options: New configuration.
  *
  * Modifies an existing device with the specified configuration (which is
  * dependent on device type).  ovs_mutex must be held.
  */
 int ovs_vport_set_options(struct vport *vport, struct nlattr *options)
 {
 	if (!vport->ops->set_options)
 		return -EOPNOTSUPP;
 	return vport->ops->set_options(vport, options);
 }

 /**
  *	ovs_vport_del - delete existing vport device
  *
  * @vport: vport to delete.
  *
  * Detaches @vport from its datapath and destroys it.  ovs_mutex must
  * be held.
  */
 void ovs_vport_del(struct vport *vport)
 {
 	hlist_del_rcu(&vport->hash_node);
 	module_put(vport->ops->owner);
 	vport->ops->destroy(vport);
 }

 /**
  *	ovs_vport_get_stats - retrieve device stats
  *
  * @vport: vport from which to retrieve the stats
  * @stats: location to store stats
  *
  * Retrieves transmit, receive, and error stats for the given device.
  *
  * Must be called with ovs_mutex or rcu_read_lock.
  */
 void ovs_vport_get_stats(struct vport *vport, struct ovs_vport_stats *stats)
 {
 	const struct rtnl_link_stats64 *dev_stats;
 	struct rtnl_link_stats64 temp;

 	dev_stats = dev_get_stats(vport->dev, &temp);
 	stats->rx_errors  = dev_stats->rx_errors;
 	stats->tx_errors  = dev_stats->tx_errors;
 	stats->tx_dropped = dev_stats->tx_dropped;
 	stats->rx_dropped = dev_stats->rx_dropped;

 	stats->rx_bytes	  = dev_stats->rx_bytes;
 	stats->rx_packets = dev_stats->rx_packets;
 	stats->tx_bytes	  = dev_stats->tx_bytes;
 	stats->tx_packets = dev_stats->tx_packets;
 }

 /**
  *	ovs_vport_get_options - retrieve device options
  *
  * @vport: vport from which to retrieve the options.
  * @skb: sk_buff where options should be appended.
  *
  * Retrieves the configuration of the given device, appending an
  * %OVS_VPORT_ATTR_OPTIONS attribute that in turn contains nested
  * vport-specific attributes to @skb.
  *
  * Returns 0 if successful, -EMSGSIZE if @skb has insufficient room, or another
  * negative error code if a real error occurred.  If an error occurs, @skb is
  * left unmodified.
  *
  * Must be called with ovs_mutex or rcu_read_lock.
  */
 int ovs_vport_get_options(const struct vport *vport, struct sk_buff *skb)
 {
 	struct nlattr *nla;
 	int err;

 	if (!vport->ops->get_options)
 		return 0;

 	nla = nla_nest_start_noflag(skb, OVS_VPORT_ATTR_OPTIONS);
 	if (!nla)
 		return -EMSGSIZE;

 	err = vport->ops->get_options(vport, skb);
 	if (err) {
 		nla_nest_cancel(skb, nla);
 		return err;
 	}

 	nla_nest_end(skb, nla);
 	return 0;
 }

 /**
  *	ovs_vport_set_upcall_portids - set upcall portids of @vport.
  *
  * @vport: vport to modify.
  * @ids: new configuration, an array of port ids.
  *
  * Sets the vport's upcall_portids to @ids.
  *
  * Returns 0 if successful, -EINVAL if @ids is zero length or cannot be parsed
  * as an array of U32.
  *
  * Must be called with ovs_mutex.
  */
 int ovs_vport_set_upcall_portids(struct vport *vport, const struct nlattr *ids)
 {
 	struct vport_portids *old, *vport_portids;

 	if (!nla_len(ids) || nla_len(ids) % sizeof(u32))
 		return -EINVAL;

 	old = ovsl_dereference(vport->upcall_portids);

 	vport_portids = kmalloc(sizeof(*vport_portids) + nla_len(ids),
 				GFP_KERNEL);
 	if (!vport_portids)
 		return -ENOMEM;

 	vport_portids->n_ids = nla_len(ids) / sizeof(u32);
 	vport_portids->rn_ids = reciprocal_value(vport_portids->n_ids);
 	nla_memcpy(vport_portids->ids, ids, nla_len(ids));

 	rcu_assign_pointer(vport->upcall_portids, vport_portids);

 	if (old)
 		kfree_rcu(old, rcu);
 	return 0;
 }

 /**
  *	ovs_vport_get_upcall_portids - get the upcall_portids of @vport.
  *
  * @vport: vport from which to retrieve the portids.
  * @skb: sk_buff where portids should be appended.
  *
  * Retrieves the configuration of the given vport, appending the
  * %OVS_VPORT_ATTR_UPCALL_PID attribute which is the array of upcall
  * portids to @skb.
  *
  * Returns 0 if successful, -EMSGSIZE if @skb has insufficient room.
  * If an error occurs, @skb is left unmodified.  Must be called with
  * ovs_mutex or rcu_read_lock.
  */
 int ovs_vport_get_upcall_portids(const struct vport *vport,
 				 struct sk_buff *skb)
 {
 	struct vport_portids *ids;

 	ids = rcu_dereference_ovsl(vport->upcall_portids);

 	if (vport->dp->user_features & OVS_DP_F_VPORT_PIDS)
 		return nla_put(skb, OVS_VPORT_ATTR_UPCALL_PID,
 			       ids->n_ids * sizeof(u32), (void *)ids->ids);
 	else
 		return nla_put_u32(skb, OVS_VPORT_ATTR_UPCALL_PID, ids->ids[0]);
 }

 /**
  *	ovs_vport_find_upcall_portid - find the upcall portid to send upcall.
  *
  * @vport: vport from which the missed packet is received.
  * @skb: skb that the missed packet was received.
  *
  * Uses the skb_get_hash() to select the upcall portid to send the
  * upcall.
  *
  * Returns the portid of the target socket.  Must be called with rcu_read_lock.
  */
 u32 ovs_vport_find_upcall_portid(const struct vport *vport,
 				 struct sk_buff *skb)
 {
 	struct vport_portids *ids;
 	u32 ids_index;
 	u32 hash;

 	ids = rcu_dereference(vport->upcall_portids);

 	/* If there is only one portid, select it in the fast-path. */
 	if (ids->n_ids == 1)
 		return ids->ids[0];

 	hash = skb_get_hash(skb);
 	ids_index = hash - ids->n_ids * reciprocal_divide(hash, ids->rn_ids);
 	return ids->ids[ids_index];
 }

 /**
  *	ovs_vport_receive - pass up received packet to the datapath for processing
  *
  * @vport: vport that received the packet
  * @skb: skb that was received
  * @tun_info: tunnel (if any) that carried packet
  *
  * Must be called with rcu_read_lock.  The packet cannot be shared and
  * skb->data should point to the Ethernet header.
  */
 int ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
 		      const struct ip_tunnel_info *tun_info)
 {
 	struct sw_flow_key key;
 	int error;

 	OVS_CB(skb)->input_vport = vport;
 	OVS_CB(skb)->mru = 0;
 	OVS_CB(skb)->cutlen = 0;
 	if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
 		u32 mark;

 		mark = skb->mark;
 		skb_scrub_packet(skb, true);
 		skb->mark = mark;
 		tun_info = NULL;
 	}

 	/* Extract flow from 'skb' into 'key'. */
 	error = ovs_flow_key_extract(tun_info, skb, &key);
 	if (unlikely(error)) {
 		kfree_skb(skb);
 		return error;
 	}
 	ovs_dp_process_packet(skb, &key);
 	return 0;
 }

 static int packet_length(const struct sk_buff *skb,
 			 struct net_device *dev)
 {
 	int length = skb->len - dev->hard_header_len;

 	if (!skb_vlan_tag_present(skb) &&
 	    eth_type_vlan(skb->protocol))
 		length -= VLAN_HLEN;

 	/* Don't subtract for multiple VLAN tags. Most (all?) drivers allow
 	 * (ETH_LEN + VLAN_HLEN) in addition to the mtu value, but almost none
 	 * account for 802.1ad. e.g. is_skb_forwardable().
 	 */

 	return length > 0 ? length : 0;
 }

 void ovs_vport_send(struct vport *vport, struct sk_buff *skb, u8 mac_proto)
 {
 	int mtu = vport->dev->mtu;

 	switch (vport->dev->type) {
 	case ARPHRD_NONE:
 		if (mac_proto == MAC_PROTO_ETHERNET) {
 			skb_reset_network_header(skb);
 			skb_reset_mac_len(skb);
 			skb->protocol = htons(ETH_P_TEB);
 		} else if (mac_proto != MAC_PROTO_NONE) {
 			WARN_ON_ONCE(1);
 			goto drop;
 		}
 		break;
 	case ARPHRD_ETHER:
 		if (mac_proto != MAC_PROTO_ETHERNET)
 			goto drop;
 		break;
 	default:
 		goto drop;
 	}

 	if (unlikely(packet_length(skb, vport->dev) > mtu &&
 		     !skb_is_gso(skb))) {
 		net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
 				     vport->dev->name,
 				     packet_length(skb, vport->dev), mtu);
 		vport->dev->stats.tx_errors++;
 		goto drop;
 	}

 	skb->dev = vport->dev;
 	skb->tstamp = 0;
 	vport->ops->send(skb);
 	return;

 drop:
 	kfree_skb(skb);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2007-2014 Nicira, Inc.
	*/

	#include <linux/etherdevice.h>
	#include <linux/if.h>
	#include <linux/if_vlan.h>
	#include <linux/jhash.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/mutex.h>
	#include <linux/percpu.h>
	#include <linux/rcupdate.h>
	#include <linux/rtnetlink.h>
	#include <linux/compat.h>
	#include <net/net_namespace.h>
	#include <linux/module.h>

	#include "datapath.h"
	#include "vport.h"
	#include "vport-internal_dev.h"

	static LIST_HEAD(vport_ops_list);

	/* Protected by RCU read lock for reading, ovs_mutex for writing. */
	static struct hlist_head *dev_table;
	#define VPORT_HASH_BUCKETS 1024

	/**
	* ovs_vport_init - initialize vport subsystem
	*
	* Called at module load time to initialize the vport subsystem.
	*/
	int ovs_vport_init(void)
	{
	dev_table = kcalloc(VPORT_HASH_BUCKETS, sizeof(struct hlist_head),
	GFP_KERNEL);
	if (!dev_table)
	return -ENOMEM;

	return 0;
	}

	/**
	* ovs_vport_exit - shutdown vport subsystem
	*
	* Called at module exit time to shutdown the vport subsystem.
	*/
	void ovs_vport_exit(void)
	{
	kfree(dev_table);
	}

	static struct hlist_head hash_bucket(const struct net net, const char *name)
	{
	unsigned int hash = jhash(name, strlen(name), (unsigned long) net);
	return &dev_table[hash & (VPORT_HASH_BUCKETS - 1)];
	}

	int __ovs_vport_ops_register(struct vport_ops *ops)
	{
	int err = -EEXIST;
	struct vport_ops *o;

	ovs_lock();
	list_for_each_entry(o, &vport_ops_list, list)
	if (ops->type == o->type)
	goto errout;

	list_add_tail(&ops->list, &vport_ops_list);
	err = 0;
	errout:
	ovs_unlock();
	return err;
	}
	EXPORT_SYMBOL_GPL(__ovs_vport_ops_register);

	void ovs_vport_ops_unregister(struct vport_ops *ops)
	{
	ovs_lock();
	list_del(&ops->list);
	ovs_unlock();
	}
	EXPORT_SYMBOL_GPL(ovs_vport_ops_unregister);

	/**
	* ovs_vport_locate - find a port that has already been created
	*
	* @net: network namespace
	* @name: name of port to find
	*
	* Must be called with ovs or RCU read lock.
	*/
	struct vport ovs_vport_locate(const struct net net, const char *name)
	{
	struct hlist_head *bucket = hash_bucket(net, name);
	struct vport *vport;

	hlist_for_each_entry_rcu(vport, bucket, hash_node,
	lockdep_ovsl_is_held())
	if (!strcmp(name, ovs_vport_name(vport)) &&
	net_eq(ovs_dp_get_net(vport->dp), net))
	return vport;

	return NULL;
	}

	/**
	* ovs_vport_alloc - allocate and initialize new vport
	*
	* @priv_size: Size of private data area to allocate.
	* @ops: vport device ops
	*
	* Allocate and initialize a new vport defined by @ops. The vport will contain
	* a private data area of size @priv_size that can be accessed using
	* vport_priv(). vports that are no longer needed should be released with
	* vport_free().
	*/
	struct vport ovs_vport_alloc(int priv_size, const struct vport_ops ops,
	const struct vport_parms *parms)
	{
	struct vport *vport;
	size_t alloc_size;

	alloc_size = sizeof(struct vport);
	if (priv_size) {
	alloc_size = ALIGN(alloc_size, VPORT_ALIGN);
	alloc_size += priv_size;
	}

	vport = kzalloc(alloc_size, GFP_KERNEL);
	if (!vport)
	return ERR_PTR(-ENOMEM);

	vport->dp = parms->dp;
	vport->port_no = parms->port_no;
	vport->ops = ops;
	INIT_HLIST_NODE(&vport->dp_hash_node);

	if (ovs_vport_set_upcall_portids(vport, parms->upcall_portids)) {
	kfree(vport);
	return ERR_PTR(-EINVAL);
	}

	return vport;
	}
	EXPORT_SYMBOL_GPL(ovs_vport_alloc);

	/**
	* ovs_vport_free - uninitialize and free vport
	*
	* @vport: vport to free
	*
	* Frees a vport allocated with vport_alloc() when it is no longer needed.
	*
	* The caller must ensure that an RCU grace period has passed since the last
	* time @vport was in a datapath.
	*/
	void ovs_vport_free(struct vport *vport)
	{
	/* vport is freed from RCU callback or error path, Therefore
	* it is safe to use raw dereference.
	*/
	kfree(rcu_dereference_raw(vport->upcall_portids));
	kfree(vport);
	}
	EXPORT_SYMBOL_GPL(ovs_vport_free);

	static struct vport_ops ovs_vport_lookup(const struct vport_parms parms)
	{
	struct vport_ops *ops;

	list_for_each_entry(ops, &vport_ops_list, list)
	if (ops->type == parms->type)
	return ops;

	return NULL;
	}

	/**
	* ovs_vport_add - add vport device (for kernel callers)
	*
	* @parms: Information about new vport.
	*
	* Creates a new vport with the specified configuration (which is dependent on
	* device type). ovs_mutex must be held.
	*/
	struct vport ovs_vport_add(const struct vport_parms parms)
	{
	struct vport_ops *ops;
	struct vport *vport;

	ops = ovs_vport_lookup(parms);
	if (ops) {
	struct hlist_head *bucket;

	if (!try_module_get(ops->owner))
	return ERR_PTR(-EAFNOSUPPORT);

	vport = ops->create(parms);
	if (IS_ERR(vport)) {
	module_put(ops->owner);
	return vport;
	}

	bucket = hash_bucket(ovs_dp_get_net(vport->dp),
	ovs_vport_name(vport));
	hlist_add_head_rcu(&vport->hash_node, bucket);
	return vport;
	}

	/* Unlock to attempt module load and return -EAGAIN if load
	* was successful as we need to restart the port addition
	* workflow.
	*/
	ovs_unlock();
	request_module("vport-type-%d", parms->type);
	ovs_lock();

	if (!ovs_vport_lookup(parms))
	return ERR_PTR(-EAFNOSUPPORT);
	else
	return ERR_PTR(-EAGAIN);
	}

	/**
	* ovs_vport_set_options - modify existing vport device (for kernel callers)
	*
	* @vport: vport to modify.
	* @options: New configuration.
	*
	* Modifies an existing device with the specified configuration (which is
	* dependent on device type). ovs_mutex must be held.
	*/
	int ovs_vport_set_options(struct vport vport, struct nlattr options)
	{
	if (!vport->ops->set_options)
	return -EOPNOTSUPP;
	return vport->ops->set_options(vport, options);
	}

	/**
	* ovs_vport_del - delete existing vport device
	*
	* @vport: vport to delete.
	*
	* Detaches @vport from its datapath and destroys it. ovs_mutex must
	* be held.
	*/
	void ovs_vport_del(struct vport *vport)
	{
	hlist_del_rcu(&vport->hash_node);
	module_put(vport->ops->owner);
	vport->ops->destroy(vport);
	}

	/**
	* ovs_vport_get_stats - retrieve device stats
	*
	* @vport: vport from which to retrieve the stats
	* @stats: location to store stats
	*
	* Retrieves transmit, receive, and error stats for the given device.
	*
	* Must be called with ovs_mutex or rcu_read_lock.
	*/
	void ovs_vport_get_stats(struct vport vport, struct ovs_vport_stats stats)
	{
	const struct rtnl_link_stats64 *dev_stats;
	struct rtnl_link_stats64 temp;

	dev_stats = dev_get_stats(vport->dev, &temp);
	stats->rx_errors = dev_stats->rx_errors;
	stats->tx_errors = dev_stats->tx_errors;
	stats->tx_dropped = dev_stats->tx_dropped;
	stats->rx_dropped = dev_stats->rx_dropped;

	stats->rx_bytes = dev_stats->rx_bytes;
	stats->rx_packets = dev_stats->rx_packets;
	stats->tx_bytes = dev_stats->tx_bytes;
	stats->tx_packets = dev_stats->tx_packets;
	}

	/**
	* ovs_vport_get_options - retrieve device options
	*
	* @vport: vport from which to retrieve the options.
	* @skb: sk_buff where options should be appended.
	*
	* Retrieves the configuration of the given device, appending an
	* %OVS_VPORT_ATTR_OPTIONS attribute that in turn contains nested
	* vport-specific attributes to @skb.
	*
	* Returns 0 if successful, -EMSGSIZE if @skb has insufficient room, or another
	* negative error code if a real error occurred. If an error occurs, @skb is
	* left unmodified.
	*
	* Must be called with ovs_mutex or rcu_read_lock.
	*/
	int ovs_vport_get_options(const struct vport vport, struct sk_buff skb)
	{
	struct nlattr *nla;
	int err;

	if (!vport->ops->get_options)
	return 0;

	nla = nla_nest_start_noflag(skb, OVS_VPORT_ATTR_OPTIONS);
	if (!nla)
	return -EMSGSIZE;

	err = vport->ops->get_options(vport, skb);
	if (err) {
	nla_nest_cancel(skb, nla);
	return err;
	}

	nla_nest_end(skb, nla);
	return 0;
	}

	/**
	* ovs_vport_set_upcall_portids - set upcall portids of @vport.
	*
	* @vport: vport to modify.
	* @ids: new configuration, an array of port ids.
	*
	* Sets the vport's upcall_portids to @ids.
	*
	* Returns 0 if successful, -EINVAL if @ids is zero length or cannot be parsed
	* as an array of U32.
	*
	* Must be called with ovs_mutex.
	*/
	int ovs_vport_set_upcall_portids(struct vport vport, const struct nlattr ids)
	{
	struct vport_portids old, vport_portids;

	if (!nla_len(ids) \|\| nla_len(ids) % sizeof(u32))
	return -EINVAL;

	old = ovsl_dereference(vport->upcall_portids);

	vport_portids = kmalloc(sizeof(*vport_portids) + nla_len(ids),
	GFP_KERNEL);
	if (!vport_portids)
	return -ENOMEM;

	vport_portids->n_ids = nla_len(ids) / sizeof(u32);
	vport_portids->rn_ids = reciprocal_value(vport_portids->n_ids);
	nla_memcpy(vport_portids->ids, ids, nla_len(ids));

	rcu_assign_pointer(vport->upcall_portids, vport_portids);

	if (old)
	kfree_rcu(old, rcu);
	return 0;
	}

	/**
	* ovs_vport_get_upcall_portids - get the upcall_portids of @vport.
	*
	* @vport: vport from which to retrieve the portids.
	* @skb: sk_buff where portids should be appended.
	*
	* Retrieves the configuration of the given vport, appending the
	* %OVS_VPORT_ATTR_UPCALL_PID attribute which is the array of upcall
	* portids to @skb.
	*
	* Returns 0 if successful, -EMSGSIZE if @skb has insufficient room.
	* If an error occurs, @skb is left unmodified. Must be called with
	* ovs_mutex or rcu_read_lock.
	*/
	int ovs_vport_get_upcall_portids(const struct vport *vport,
	struct sk_buff *skb)
	{
	struct vport_portids *ids;

	ids = rcu_dereference_ovsl(vport->upcall_portids);

	if (vport->dp->user_features & OVS_DP_F_VPORT_PIDS)
	return nla_put(skb, OVS_VPORT_ATTR_UPCALL_PID,
	ids->n_ids * sizeof(u32), (void *)ids->ids);
	else
	return nla_put_u32(skb, OVS_VPORT_ATTR_UPCALL_PID, ids->ids[0]);
	}

	/**
	* ovs_vport_find_upcall_portid - find the upcall portid to send upcall.
	*
	* @vport: vport from which the missed packet is received.
	* @skb: skb that the missed packet was received.
	*
	* Uses the skb_get_hash() to select the upcall portid to send the
	* upcall.
	*
	* Returns the portid of the target socket. Must be called with rcu_read_lock.
	*/
	u32 ovs_vport_find_upcall_portid(const struct vport *vport,
	struct sk_buff *skb)
	{
	struct vport_portids *ids;
	u32 ids_index;
	u32 hash;

	ids = rcu_dereference(vport->upcall_portids);

	/* If there is only one portid, select it in the fast-path. */
	if (ids->n_ids == 1)
	return ids->ids[0];

	hash = skb_get_hash(skb);
	ids_index = hash - ids->n_ids * reciprocal_divide(hash, ids->rn_ids);
	return ids->ids[ids_index];
	}

	/**
	* ovs_vport_receive - pass up received packet to the datapath for processing
	*
	* @vport: vport that received the packet
	* @skb: skb that was received
	* @tun_info: tunnel (if any) that carried packet
	*
	* Must be called with rcu_read_lock. The packet cannot be shared and
	* skb->data should point to the Ethernet header.
	*/
	int ovs_vport_receive(struct vport vport, struct sk_buff skb,
	const struct ip_tunnel_info *tun_info)
	{
	struct sw_flow_key key;
	int error;

	OVS_CB(skb)->input_vport = vport;
	OVS_CB(skb)->mru = 0;
	OVS_CB(skb)->cutlen = 0;
	if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) {
	u32 mark;

	mark = skb->mark;
	skb_scrub_packet(skb, true);
	skb->mark = mark;
	tun_info = NULL;
	}

	/* Extract flow from 'skb' into 'key'. */
	error = ovs_flow_key_extract(tun_info, skb, &key);
	if (unlikely(error)) {
	kfree_skb(skb);
	return error;
	}
	ovs_dp_process_packet(skb, &key);
	return 0;
	}

	static int packet_length(const struct sk_buff *skb,
	struct net_device *dev)
	{
	int length = skb->len - dev->hard_header_len;

	if (!skb_vlan_tag_present(skb) &&
	eth_type_vlan(skb->protocol))
	length -= VLAN_HLEN;

	/* Don't subtract for multiple VLAN tags. Most (all?) drivers allow
	* (ETH_LEN + VLAN_HLEN) in addition to the mtu value, but almost none
	* account for 802.1ad. e.g. is_skb_forwardable().
	*/

	return length > 0 ? length : 0;
	}

	void ovs_vport_send(struct vport vport, struct sk_buff skb, u8 mac_proto)
	{
	int mtu = vport->dev->mtu;

	switch (vport->dev->type) {
	case ARPHRD_NONE:
	if (mac_proto == MAC_PROTO_ETHERNET) {
	skb_reset_network_header(skb);
	skb_reset_mac_len(skb);
	skb->protocol = htons(ETH_P_TEB);
	} else if (mac_proto != MAC_PROTO_NONE) {
	WARN_ON_ONCE(1);
	goto drop;
	}
	break;
	case ARPHRD_ETHER:
	if (mac_proto != MAC_PROTO_ETHERNET)
	goto drop;
	break;
	default:
	goto drop;
	}

	if (unlikely(packet_length(skb, vport->dev) > mtu &&
	!skb_is_gso(skb))) {
	net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
	vport->dev->name,
	packet_length(skb, vport->dev), mtu);
	vport->dev->stats.tx_errors++;
	goto drop;
	}

	skb->dev = vport->dev;
	skb->tstamp = 0;
	vport->ops->send(skb);
	return;

	drop:
	kfree_skb(skb);
	}