/*

   * Copyright (c) 2007-2012 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/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 "datapath.h"

  #include "vport.h"
  #include "vport-internal_dev.h"
  
  /* List of statically compiled vport implementations.  Don't forget to also
   * add yours to the list at the bottom of vport.h. */
  static const struct vport_ops *vport_ops_list[] = {
  	&ovs_netdev_vport_ops,
  	&ovs_internal_vport_ops,
  };

  /* 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 = kzalloc(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(struct net *net, const char *name)

  {

  	unsigned int hash = jhash(name, strlen(name), (unsigned long) net);

  	return &dev_table[hash & (VPORT_HASH_BUCKETS - 1)];
  }
  
  /**
   *	ovs_vport_locate - find a port that has already been created
   *
   * @name: name of port to find
   *

   * Must be called with ovs or RCU read lock.

   */

  struct vport *ovs_vport_locate(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)

  		if (!strcmp(name, vport->ops->get_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->upcall_portid = parms->upcall_portid;

  	vport->ops = ops;

  	INIT_HLIST_NODE(&vport->dp_hash_node);

  	vport->percpu_stats = alloc_percpu(struct pcpu_tstats);

  	if (!vport->percpu_stats) {
  		kfree(vport);

  		return ERR_PTR(-ENOMEM);

  	}

  
  	spin_lock_init(&vport->stats_lock);
  
  	return vport;
  }
  
  /**
   *	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)
  {
  	free_percpu(vport->percpu_stats);
  	kfree(vport);
  }
  
  /**
   *	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 *vport;
  	int err = 0;
  	int i;

  	for (i = 0; i < ARRAY_SIZE(vport_ops_list); i++) {
  		if (vport_ops_list[i]->type == parms->type) {

  			struct hlist_head *bucket;

  			vport = vport_ops_list[i]->create(parms);
  			if (IS_ERR(vport)) {
  				err = PTR_ERR(vport);
  				goto out;
  			}

  			bucket = hash_bucket(ovs_dp_get_net(vport->dp),
  					     vport->ops->get_name(vport));
  			hlist_add_head_rcu(&vport->hash_node, bucket);

  			return vport;
  		}
  	}
  
  	err = -EAFNOSUPPORT;
  
  out:
  	return ERR_PTR(err);
  }
  
  /**
   *	ovs_vport_set_options - modify existing vport device (for kernel callers)
   *
   * @vport: vport to modify.
   * @port: 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.  It is possible to fail

   * for reasons such as lack of memory.  ovs_mutex must be held.

   */
  void ovs_vport_del(struct vport *vport)
  {

  	ASSERT_OVSL();

  
  	hlist_del_rcu(&vport->hash_node);
  
  	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)
  {
  	int i;
  
  	memset(stats, 0, sizeof(*stats));
  
  	/* We potentially have 2 sources of stats that need to be combined:
  	 * those we have collected (split into err_stats and percpu_stats) from
  	 * set_stats() and device error stats from netdev->get_stats() (for
  	 * errors that happen  downstream and therefore aren't reported through
  	 * our vport_record_error() function).
  	 * Stats from first source are reported by ovs (OVS_VPORT_ATTR_STATS).
  	 * netdev-stats can be directly read over netlink-ioctl.
  	 */
  
  	spin_lock_bh(&vport->stats_lock);
  
  	stats->rx_errors	= vport->err_stats.rx_errors;
  	stats->tx_errors	= vport->err_stats.tx_errors;
  	stats->tx_dropped	= vport->err_stats.tx_dropped;
  	stats->rx_dropped	= vport->err_stats.rx_dropped;
  
  	spin_unlock_bh(&vport->stats_lock);
  
  	for_each_possible_cpu(i) {

  		const struct pcpu_tstats *percpu_stats;
  		struct pcpu_tstats local_stats;

  		unsigned int start;
  
  		percpu_stats = per_cpu_ptr(vport->percpu_stats, i);
  
  		do {

  			start = u64_stats_fetch_begin_bh(&percpu_stats->syncp);

  			local_stats = *percpu_stats;

  		} while (u64_stats_fetch_retry_bh(&percpu_stats->syncp, start));

  
  		stats->rx_bytes		+= local_stats.rx_bytes;
  		stats->rx_packets	+= local_stats.rx_packets;
  		stats->tx_bytes		+= local_stats.tx_bytes;
  		stats->tx_packets	+= local_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(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_receive - pass up received packet to the datapath for processing
   *
   * @vport: vport that received the packet
   * @skb: skb that was received
   *
   * Must be called with rcu_read_lock.  The packet cannot be shared and

   * skb->data should point to the Ethernet header.

   */
  void ovs_vport_receive(struct vport *vport, struct sk_buff *skb)
  {

  	struct pcpu_tstats *stats;

  	stats = this_cpu_ptr(vport->percpu_stats);

  	u64_stats_update_begin(&stats->syncp);

  	stats->rx_packets++;
  	stats->rx_bytes += skb->len;

  	u64_stats_update_end(&stats->syncp);

  
  	ovs_dp_process_received_packet(vport, skb);
  }
  
  /**
   *	ovs_vport_send - send a packet on a device
   *
   * @vport: vport on which to send the packet
   * @skb: skb to send
   *

   * Sends the given packet and returns the length of data sent.  Either ovs

   * lock or rcu_read_lock must be held.
   */
  int ovs_vport_send(struct vport *vport, struct sk_buff *skb)
  {
  	int sent = vport->ops->send(vport, skb);
  
  	if (likely(sent)) {

  		struct pcpu_tstats *stats;

  		stats = this_cpu_ptr(vport->percpu_stats);

  		u64_stats_update_begin(&stats->syncp);

  		stats->tx_packets++;
  		stats->tx_bytes += sent;

  		u64_stats_update_end(&stats->syncp);

  	}
  	return sent;
  }
  
  /**
   *	ovs_vport_record_error - indicate device error to generic stats layer
   *
   * @vport: vport that encountered the error
   * @err_type: one of enum vport_err_type types to indicate the error type
   *
   * If using the vport generic stats layer indicate that an error of the given
   * type has occured.
   */
  void ovs_vport_record_error(struct vport *vport, enum vport_err_type err_type)
  {
  	spin_lock(&vport->stats_lock);
  
  	switch (err_type) {
  	case VPORT_E_RX_DROPPED:
  		vport->err_stats.rx_dropped++;
  		break;
  
  	case VPORT_E_RX_ERROR:
  		vport->err_stats.rx_errors++;
  		break;
  
  	case VPORT_E_TX_DROPPED:
  		vport->err_stats.tx_dropped++;
  		break;
  
  	case VPORT_E_TX_ERROR:
  		vport->err_stats.tx_errors++;
  		break;

  	}

  
  	spin_unlock(&vport->stats_lock);
  }