/* Copyright (C) 2013-2017  B.A.T.M.A.N. contributors:

   *
   * Linus Lüssing, Marek Lindner
   *
   * 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, see <http://www.gnu.org/licenses/>.
   */

  #include "bat_v.h"

  #include "main.h"

  #include <linux/atomic.h>

  #include <linux/bug.h>

  #include <linux/cache.h>

  #include <linux/errno.h>

  #include <linux/if_ether.h>

  #include <linux/init.h>

  #include <linux/jiffies.h>

  #include <linux/kernel.h>

  #include <linux/kref.h>

  #include <linux/netdevice.h>

  #include <linux/netlink.h>

  #include <linux/rculist.h>
  #include <linux/rcupdate.h>
  #include <linux/seq_file.h>

  #include <linux/stddef.h>

  #include <linux/types.h>

  #include <linux/workqueue.h>

  #include <net/genetlink.h>
  #include <net/netlink.h>
  #include <uapi/linux/batman_adv.h>

  #include "bat_algo.h"

  #include "bat_v_elp.h"

  #include "bat_v_ogm.h"

  #include "gateway_client.h"
  #include "gateway_common.h"

  #include "hard-interface.h"

  #include "hash.h"

  #include "log.h"

  #include "netlink.h"

  #include "originator.h"

  #include "packet.h"

  struct sk_buff;

  static void batadv_v_iface_activate(struct batadv_hard_iface *hard_iface)
  {

  	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  	struct batadv_hard_iface *primary_if;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  
  	if (primary_if) {
  		batadv_v_elp_iface_activate(primary_if, hard_iface);
  		batadv_hardif_put(primary_if);
  	}

  	/* B.A.T.M.A.N. V does not use any queuing mechanism, therefore it can
  	 * set the interface as ACTIVE right away, without any risk of race
  	 * condition
  	 */
  	if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
  		hard_iface->if_status = BATADV_IF_ACTIVE;
  }

  static int batadv_v_iface_enable(struct batadv_hard_iface *hard_iface)
  {

  	int ret;
  
  	ret = batadv_v_elp_iface_enable(hard_iface);
  	if (ret < 0)
  		return ret;
  
  	ret = batadv_v_ogm_iface_enable(hard_iface);
  	if (ret < 0)
  		batadv_v_elp_iface_disable(hard_iface);
  
  	return ret;

  }
  
  static void batadv_v_iface_disable(struct batadv_hard_iface *hard_iface)
  {
  	batadv_v_elp_iface_disable(hard_iface);
  }

  static void batadv_v_primary_iface_set(struct batadv_hard_iface *hard_iface)
  {
  	batadv_v_elp_primary_iface_set(hard_iface);

  	batadv_v_ogm_primary_iface_set(hard_iface);

  }

  /**
   * batadv_v_iface_update_mac - react to hard-interface MAC address change
   * @hard_iface: the modified interface
   *
   * If the modified interface is the primary one, update the originator
   * address in the ELP and OGM messages to reflect the new MAC address.
   */
  static void batadv_v_iface_update_mac(struct batadv_hard_iface *hard_iface)
  {
  	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
  	struct batadv_hard_iface *primary_if;
  
  	primary_if = batadv_primary_if_get_selected(bat_priv);
  	if (primary_if != hard_iface)
  		goto out;
  
  	batadv_v_primary_iface_set(hard_iface);
  out:
  	if (primary_if)
  		batadv_hardif_put(primary_if);
  }

  static void
  batadv_v_hardif_neigh_init(struct batadv_hardif_neigh_node *hardif_neigh)
  {
  	ewma_throughput_init(&hardif_neigh->bat_v.throughput);

  	INIT_WORK(&hardif_neigh->bat_v.metric_work,
  		  batadv_v_elp_throughput_metric_update);

  }

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  /**
   * batadv_v_orig_print_neigh - print neighbors for the originator table
   * @orig_node: the orig_node for which the neighbors are printed
   * @if_outgoing: outgoing interface for these entries
   * @seq: debugfs table seq_file struct
   *
   * Must be called while holding an rcu lock.
   */
  static void
  batadv_v_orig_print_neigh(struct batadv_orig_node *orig_node,
  			  struct batadv_hard_iface *if_outgoing,
  			  struct seq_file *seq)
  {
  	struct batadv_neigh_node *neigh_node;
  	struct batadv_neigh_ifinfo *n_ifinfo;
  
  	hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
  		n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
  		if (!n_ifinfo)
  			continue;
  
  		seq_printf(seq, " %pM (%9u.%1u)",
  			   neigh_node->addr,
  			   n_ifinfo->bat_v.throughput / 10,
  			   n_ifinfo->bat_v.throughput % 10);
  
  		batadv_neigh_ifinfo_put(n_ifinfo);
  	}
  }
  
  /**

   * batadv_v_hardif_neigh_print - print a single ELP neighbour node
   * @seq: neighbour table seq_file struct
   * @hardif_neigh: hardif neighbour information
   */
  static void
  batadv_v_hardif_neigh_print(struct seq_file *seq,
  			    struct batadv_hardif_neigh_node *hardif_neigh)
  {
  	int last_secs, last_msecs;
  	u32 throughput;
  
  	last_secs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen) / 1000;
  	last_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen) % 1000;
  	throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
  
  	seq_printf(seq, "%pM %4i.%03is (%9u.%1u) [%10s]
  ",
  		   hardif_neigh->addr, last_secs, last_msecs, throughput / 10,
  		   throughput % 10, hardif_neigh->if_incoming->net_dev->name);
  }
  
  /**
   * batadv_v_neigh_print - print the single hop neighbour list
   * @bat_priv: the bat priv with all the soft interface information
   * @seq: neighbour table seq_file struct
   */
  static void batadv_v_neigh_print(struct batadv_priv *bat_priv,
  				 struct seq_file *seq)
  {
  	struct net_device *net_dev = (struct net_device *)seq->private;
  	struct batadv_hardif_neigh_node *hardif_neigh;
  	struct batadv_hard_iface *hard_iface;
  	int batman_count = 0;

  	seq_puts(seq,
  		 "  Neighbor        last-seen ( throughput) [        IF]
  ");

  
  	rcu_read_lock();
  	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  		if (hard_iface->soft_iface != net_dev)
  			continue;
  
  		hlist_for_each_entry_rcu(hardif_neigh,
  					 &hard_iface->neigh_list, list) {
  			batadv_v_hardif_neigh_print(seq, hardif_neigh);
  			batman_count++;
  		}
  	}
  	rcu_read_unlock();
  
  	if (batman_count == 0)
  		seq_puts(seq, "No batman nodes in range ...
  ");
  }

  #endif

  
  /**

   * batadv_v_neigh_dump_neigh - Dump a neighbour into a message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @hardif_neigh: Neighbour to dump
   *
   * Return: Error code, or 0 on success
   */
  static int
  batadv_v_neigh_dump_neigh(struct sk_buff *msg, u32 portid, u32 seq,
  			  struct batadv_hardif_neigh_node *hardif_neigh)
  {
  	void *hdr;
  	unsigned int last_seen_msecs;
  	u32 throughput;
  
  	last_seen_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen);
  	throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
  	throughput = throughput * 100;
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, NLM_F_MULTI,
  			  BATADV_CMD_GET_NEIGHBORS);
  	if (!hdr)
  		return -ENOBUFS;
  
  	if (nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
  		    hardif_neigh->addr) ||
  	    nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
  			hardif_neigh->if_incoming->net_dev->ifindex) ||
  	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS,
  			last_seen_msecs) ||
  	    nla_put_u32(msg, BATADV_ATTR_THROUGHPUT, throughput))
  		goto nla_put_failure;
  
  	genlmsg_end(msg, hdr);
  	return 0;
  
   nla_put_failure:
  	genlmsg_cancel(msg, hdr);
  	return -EMSGSIZE;
  }
  
  /**
   * batadv_v_neigh_dump_hardif - Dump the  neighbours of a hard interface  into
   *  a message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @bat_priv: The bat priv with all the soft interface information
   * @hard_iface: The hard interface to be dumped
   * @idx_s: Entries to be skipped
   *
   * This function assumes the caller holds rcu_read_lock().
   *
   * Return: Error code, or 0 on success
   */
  static int
  batadv_v_neigh_dump_hardif(struct sk_buff *msg, u32 portid, u32 seq,
  			   struct batadv_priv *bat_priv,
  			   struct batadv_hard_iface *hard_iface,
  			   int *idx_s)
  {
  	struct batadv_hardif_neigh_node *hardif_neigh;
  	int idx = 0;
  
  	hlist_for_each_entry_rcu(hardif_neigh,
  				 &hard_iface->neigh_list, list) {
  		if (idx++ < *idx_s)
  			continue;
  
  		if (batadv_v_neigh_dump_neigh(msg, portid, seq, hardif_neigh)) {
  			*idx_s = idx - 1;
  			return -EMSGSIZE;
  		}
  	}
  
  	*idx_s = 0;
  	return 0;
  }
  
  /**
   * batadv_v_neigh_dump - Dump the neighbours of a hard interface  into a
   *  message
   * @msg: Netlink message to dump into
   * @cb: Control block containing additional options
   * @bat_priv: The bat priv with all the soft interface information
   * @single_hardif: Limit dumping to this hard interface
   */
  static void
  batadv_v_neigh_dump(struct sk_buff *msg, struct netlink_callback *cb,
  		    struct batadv_priv *bat_priv,
  		    struct batadv_hard_iface *single_hardif)
  {
  	struct batadv_hard_iface *hard_iface;
  	int i_hardif = 0;
  	int i_hardif_s = cb->args[0];
  	int idx = cb->args[1];
  	int portid = NETLINK_CB(cb->skb).portid;
  
  	rcu_read_lock();
  	if (single_hardif) {
  		if (i_hardif_s == 0) {
  			if (batadv_v_neigh_dump_hardif(msg, portid,
  						       cb->nlh->nlmsg_seq,
  						       bat_priv, single_hardif,
  						       &idx) == 0)
  				i_hardif++;
  		}
  	} else {
  		list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
  			if (hard_iface->soft_iface != bat_priv->soft_iface)
  				continue;
  
  			if (i_hardif++ < i_hardif_s)
  				continue;
  
  			if (batadv_v_neigh_dump_hardif(msg, portid,
  						       cb->nlh->nlmsg_seq,
  						       bat_priv, hard_iface,
  						       &idx)) {
  				i_hardif--;
  				break;
  			}
  		}
  	}
  	rcu_read_unlock();
  
  	cb->args[0] = i_hardif;
  	cb->args[1] = idx;
  }

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  /**

   * batadv_v_orig_print - print the originator table
   * @bat_priv: the bat priv with all the soft interface information
   * @seq: debugfs table seq_file struct
   * @if_outgoing: the outgoing interface for which this should be printed
   */
  static void batadv_v_orig_print(struct batadv_priv *bat_priv,
  				struct seq_file *seq,
  				struct batadv_hard_iface *if_outgoing)
  {
  	struct batadv_neigh_node *neigh_node;
  	struct batadv_hashtable *hash = bat_priv->orig_hash;
  	int last_seen_msecs, last_seen_secs;
  	struct batadv_orig_node *orig_node;
  	struct batadv_neigh_ifinfo *n_ifinfo;
  	unsigned long last_seen_jiffies;
  	struct hlist_head *head;
  	int batman_count = 0;
  	u32 i;

  	seq_puts(seq,
  		 "  Originator      last-seen ( throughput)           Nexthop [outgoingIF]:   Potential nexthops ...
  ");

  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];
  
  		rcu_read_lock();
  		hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
  			neigh_node = batadv_orig_router_get(orig_node,
  							    if_outgoing);
  			if (!neigh_node)
  				continue;
  
  			n_ifinfo = batadv_neigh_ifinfo_get(neigh_node,
  							   if_outgoing);
  			if (!n_ifinfo)
  				goto next;
  
  			last_seen_jiffies = jiffies - orig_node->last_seen;
  			last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
  			last_seen_secs = last_seen_msecs / 1000;
  			last_seen_msecs = last_seen_msecs % 1000;
  
  			seq_printf(seq, "%pM %4i.%03is (%9u.%1u) %pM [%10s]:",
  				   orig_node->orig, last_seen_secs,
  				   last_seen_msecs,
  				   n_ifinfo->bat_v.throughput / 10,
  				   n_ifinfo->bat_v.throughput % 10,
  				   neigh_node->addr,
  				   neigh_node->if_incoming->net_dev->name);
  
  			batadv_v_orig_print_neigh(orig_node, if_outgoing, seq);

  			seq_putc(seq, '
  ');

  			batman_count++;
  
  next:
  			batadv_neigh_node_put(neigh_node);
  			if (n_ifinfo)
  				batadv_neigh_ifinfo_put(n_ifinfo);
  		}
  		rcu_read_unlock();
  	}
  
  	if (batman_count == 0)
  		seq_puts(seq, "No batman nodes in range ...
  ");
  }

  #endif

  /**
   * batadv_v_orig_dump_subentry - Dump an originator subentry into a
   *  message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @bat_priv: The bat priv with all the soft interface information
   * @if_outgoing: Limit dump to entries with this outgoing interface
   * @orig_node: Originator to dump
   * @neigh_node: Single hops neighbour
   * @best: Is the best originator
   *
   * Return: Error code, or 0 on success
   */
  static int
  batadv_v_orig_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
  			    struct batadv_priv *bat_priv,
  			    struct batadv_hard_iface *if_outgoing,
  			    struct batadv_orig_node *orig_node,
  			    struct batadv_neigh_node *neigh_node,
  			    bool best)
  {
  	struct batadv_neigh_ifinfo *n_ifinfo;
  	unsigned int last_seen_msecs;
  	u32 throughput;
  	void *hdr;
  
  	n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
  	if (!n_ifinfo)
  		return 0;
  
  	throughput = n_ifinfo->bat_v.throughput * 100;
  
  	batadv_neigh_ifinfo_put(n_ifinfo);
  
  	last_seen_msecs = jiffies_to_msecs(jiffies - orig_node->last_seen);
  
  	if (if_outgoing != BATADV_IF_DEFAULT &&
  	    if_outgoing != neigh_node->if_incoming)
  		return 0;
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, NLM_F_MULTI,
  			  BATADV_CMD_GET_ORIGINATORS);
  	if (!hdr)
  		return -ENOBUFS;
  
  	if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN, orig_node->orig) ||
  	    nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
  		    neigh_node->addr) ||
  	    nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
  			neigh_node->if_incoming->net_dev->ifindex) ||
  	    nla_put_u32(msg, BATADV_ATTR_THROUGHPUT, throughput) ||
  	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS,
  			last_seen_msecs))
  		goto nla_put_failure;
  
  	if (best && nla_put_flag(msg, BATADV_ATTR_FLAG_BEST))
  		goto nla_put_failure;
  
  	genlmsg_end(msg, hdr);
  	return 0;
  
   nla_put_failure:
  	genlmsg_cancel(msg, hdr);
  	return -EMSGSIZE;
  }
  
  /**
   * batadv_v_orig_dump_entry - Dump an originator entry into a message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @bat_priv: The bat priv with all the soft interface information
   * @if_outgoing: Limit dump to entries with this outgoing interface
   * @orig_node: Originator to dump
   * @sub_s: Number of sub entries to skip
   *
   * This function assumes the caller holds rcu_read_lock().
   *
   * Return: Error code, or 0 on success
   */
  static int
  batadv_v_orig_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
  			 struct batadv_priv *bat_priv,
  			 struct batadv_hard_iface *if_outgoing,
  			 struct batadv_orig_node *orig_node, int *sub_s)
  {
  	struct batadv_neigh_node *neigh_node_best;
  	struct batadv_neigh_node *neigh_node;
  	int sub = 0;
  	bool best;
  
  	neigh_node_best = batadv_orig_router_get(orig_node, if_outgoing);
  	if (!neigh_node_best)
  		goto out;
  
  	hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
  		if (sub++ < *sub_s)
  			continue;
  
  		best = (neigh_node == neigh_node_best);
  
  		if (batadv_v_orig_dump_subentry(msg, portid, seq, bat_priv,
  						if_outgoing, orig_node,
  						neigh_node, best)) {
  			batadv_neigh_node_put(neigh_node_best);
  
  			*sub_s = sub - 1;
  			return -EMSGSIZE;
  		}
  	}
  
   out:
  	if (neigh_node_best)
  		batadv_neigh_node_put(neigh_node_best);
  
  	*sub_s = 0;
  	return 0;
  }
  
  /**
   * batadv_v_orig_dump_bucket - Dump an originator bucket into a
   *  message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @bat_priv: The bat priv with all the soft interface information
   * @if_outgoing: Limit dump to entries with this outgoing interface
   * @head: Bucket to be dumped
   * @idx_s: Number of entries to be skipped
   * @sub: Number of sub entries to be skipped
   *
   * Return: Error code, or 0 on success
   */
  static int
  batadv_v_orig_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
  			  struct batadv_priv *bat_priv,
  			  struct batadv_hard_iface *if_outgoing,
  			  struct hlist_head *head, int *idx_s, int *sub)
  {
  	struct batadv_orig_node *orig_node;
  	int idx = 0;
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
  		if (idx++ < *idx_s)
  			continue;
  
  		if (batadv_v_orig_dump_entry(msg, portid, seq, bat_priv,
  					     if_outgoing, orig_node, sub)) {
  			rcu_read_unlock();
  			*idx_s = idx - 1;
  			return -EMSGSIZE;
  		}
  	}
  	rcu_read_unlock();
  
  	*idx_s = 0;
  	*sub = 0;
  	return 0;
  }
  
  /**
   * batadv_v_orig_dump - Dump the originators into a message
   * @msg: Netlink message to dump into
   * @cb: Control block containing additional options
   * @bat_priv: The bat priv with all the soft interface information
   * @if_outgoing: Limit dump to entries with this outgoing interface
   */
  static void
  batadv_v_orig_dump(struct sk_buff *msg, struct netlink_callback *cb,
  		   struct batadv_priv *bat_priv,
  		   struct batadv_hard_iface *if_outgoing)
  {
  	struct batadv_hashtable *hash = bat_priv->orig_hash;
  	struct hlist_head *head;
  	int bucket = cb->args[0];
  	int idx = cb->args[1];
  	int sub = cb->args[2];
  	int portid = NETLINK_CB(cb->skb).portid;
  
  	while (bucket < hash->size) {
  		head = &hash->table[bucket];
  
  		if (batadv_v_orig_dump_bucket(msg, portid,
  					      cb->nlh->nlmsg_seq,
  					      bat_priv, if_outgoing, head, &idx,
  					      &sub))
  			break;
  
  		bucket++;
  	}
  
  	cb->args[0] = bucket;
  	cb->args[1] = idx;
  	cb->args[2] = sub;
  }

  static int batadv_v_neigh_cmp(struct batadv_neigh_node *neigh1,
  			      struct batadv_hard_iface *if_outgoing1,
  			      struct batadv_neigh_node *neigh2,
  			      struct batadv_hard_iface *if_outgoing2)
  {
  	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;

  	int ret = 0;

  
  	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);

  	if (WARN_ON(!ifinfo1))
  		goto err_ifinfo1;

  	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);

  	if (WARN_ON(!ifinfo2))
  		goto err_ifinfo2;

  	ret = ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;

  	batadv_neigh_ifinfo_put(ifinfo2);
  err_ifinfo2:
  	batadv_neigh_ifinfo_put(ifinfo1);
  err_ifinfo1:
  	return ret;

  }
  
  static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
  				  struct batadv_hard_iface *if_outgoing1,
  				  struct batadv_neigh_node *neigh2,
  				  struct batadv_hard_iface *if_outgoing2)
  {
  	struct batadv_neigh_ifinfo *ifinfo1, *ifinfo2;
  	u32 threshold;

  	bool ret = false;

  
  	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);

  	if (WARN_ON(!ifinfo1))
  		goto err_ifinfo1;

  	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
  	if (WARN_ON(!ifinfo2))
  		goto err_ifinfo2;

  	threshold = ifinfo1->bat_v.throughput / 4;
  	threshold = ifinfo1->bat_v.throughput - threshold;

  	ret = ifinfo2->bat_v.throughput > threshold;
  
  	batadv_neigh_ifinfo_put(ifinfo2);
  err_ifinfo2:
  	batadv_neigh_ifinfo_put(ifinfo1);
  err_ifinfo1:
  	return ret;

  }

  /**
   * batadv_v_init_sel_class - initialize GW selection class
   * @bat_priv: the bat priv with all the soft interface information
   */
  static void batadv_v_init_sel_class(struct batadv_priv *bat_priv)
  {
  	/* set default throughput difference threshold to 5Mbps */
  	atomic_set(&bat_priv->gw.sel_class, 50);
  }

  static ssize_t batadv_v_store_sel_class(struct batadv_priv *bat_priv,
  					char *buff, size_t count)
  {
  	u32 old_class, class;
  
  	if (!batadv_parse_throughput(bat_priv->soft_iface, buff,
  				     "B.A.T.M.A.N. V GW selection class",
  				     &class))
  		return -EINVAL;
  
  	old_class = atomic_read(&bat_priv->gw.sel_class);
  	atomic_set(&bat_priv->gw.sel_class, class);
  
  	if (old_class != class)
  		batadv_gw_reselect(bat_priv);
  
  	return count;
  }
  
  static ssize_t batadv_v_show_sel_class(struct batadv_priv *bat_priv, char *buff)
  {
  	u32 class = atomic_read(&bat_priv->gw.sel_class);
  
  	return sprintf(buff, "%u.%u MBit
  ", class / 10, class % 10);
  }

  /**
   * batadv_v_gw_throughput_get - retrieve the GW-bandwidth for a given GW
   * @gw_node: the GW to retrieve the metric for
   * @bw: the pointer where the metric will be stored. The metric is computed as
   *  the minimum between the GW advertised throughput and the path throughput to
   *  it in the mesh
   *
   * Return: 0 on success, -1 on failure
   */
  static int batadv_v_gw_throughput_get(struct batadv_gw_node *gw_node, u32 *bw)
  {
  	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
  	struct batadv_orig_node *orig_node;
  	struct batadv_neigh_node *router;
  	int ret = -1;
  
  	orig_node = gw_node->orig_node;
  	router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
  	if (!router)
  		goto out;
  
  	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
  	if (!router_ifinfo)
  		goto out;
  
  	/* the GW metric is computed as the minimum between the path throughput
  	 * to reach the GW itself and the advertised bandwidth.
  	 * This gives us an approximation of the effective throughput that the
  	 * client can expect via this particular GW node
  	 */
  	*bw = router_ifinfo->bat_v.throughput;
  	*bw = min_t(u32, *bw, gw_node->bandwidth_down);
  
  	ret = 0;
  out:
  	if (router)
  		batadv_neigh_node_put(router);
  	if (router_ifinfo)
  		batadv_neigh_ifinfo_put(router_ifinfo);
  
  	return ret;
  }
  
  /**
   * batadv_v_gw_get_best_gw_node - retrieve the best GW node
   * @bat_priv: the bat priv with all the soft interface information
   *
   * Return: the GW node having the best GW-metric, NULL if no GW is known
   */
  static struct batadv_gw_node *
  batadv_v_gw_get_best_gw_node(struct batadv_priv *bat_priv)
  {
  	struct batadv_gw_node *gw_node, *curr_gw = NULL;
  	u32 max_bw = 0, bw;
  
  	rcu_read_lock();

  	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {

  		if (!kref_get_unless_zero(&gw_node->refcount))
  			continue;
  
  		if (batadv_v_gw_throughput_get(gw_node, &bw) < 0)
  			goto next;
  
  		if (curr_gw && (bw <= max_bw))
  			goto next;
  
  		if (curr_gw)
  			batadv_gw_node_put(curr_gw);
  
  		curr_gw = gw_node;
  		kref_get(&curr_gw->refcount);
  		max_bw = bw;
  
  next:
  		batadv_gw_node_put(gw_node);
  	}
  	rcu_read_unlock();
  
  	return curr_gw;
  }
  
  /**
   * batadv_v_gw_is_eligible - check if a originator would be selected as GW
   * @bat_priv: the bat priv with all the soft interface information
   * @curr_gw_orig: originator representing the currently selected GW
   * @orig_node: the originator representing the new candidate
   *
   * Return: true if orig_node can be selected as current GW, false otherwise
   */
  static bool batadv_v_gw_is_eligible(struct batadv_priv *bat_priv,
  				    struct batadv_orig_node *curr_gw_orig,
  				    struct batadv_orig_node *orig_node)
  {

  	struct batadv_gw_node *curr_gw, *orig_gw = NULL;

  	u32 gw_throughput, orig_throughput, threshold;
  	bool ret = false;
  
  	threshold = atomic_read(&bat_priv->gw.sel_class);
  
  	curr_gw = batadv_gw_node_get(bat_priv, curr_gw_orig);
  	if (!curr_gw) {
  		ret = true;
  		goto out;
  	}
  
  	if (batadv_v_gw_throughput_get(curr_gw, &gw_throughput) < 0) {
  		ret = true;
  		goto out;
  	}
  
  	orig_gw = batadv_gw_node_get(bat_priv, orig_node);
  	if (!orig_node)
  		goto out;
  
  	if (batadv_v_gw_throughput_get(orig_gw, &orig_throughput) < 0)
  		goto out;
  
  	if (orig_throughput < gw_throughput)
  		goto out;
  
  	if ((orig_throughput - gw_throughput) < threshold)
  		goto out;
  
  	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
  		   "Restarting gateway selection: better gateway found (throughput curr: %u, throughput new: %u)
  ",
  		   gw_throughput, orig_throughput);
  
  	ret = true;
  out:
  	if (curr_gw)
  		batadv_gw_node_put(curr_gw);
  	if (orig_gw)
  		batadv_gw_node_put(orig_gw);
  
  	return ret;
  }

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  /* fails if orig_node has no router */
  static int batadv_v_gw_write_buffer_text(struct batadv_priv *bat_priv,
  					 struct seq_file *seq,
  					 const struct batadv_gw_node *gw_node)
  {
  	struct batadv_gw_node *curr_gw;
  	struct batadv_neigh_node *router;
  	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
  	int ret = -1;
  
  	router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
  	if (!router)
  		goto out;
  
  	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
  	if (!router_ifinfo)
  		goto out;
  
  	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
  
  	seq_printf(seq, "%s %pM (%9u.%1u) %pM [%10s]: %u.%u/%u.%u MBit
  ",
  		   (curr_gw == gw_node ? "=>" : "  "),
  		   gw_node->orig_node->orig,
  		   router_ifinfo->bat_v.throughput / 10,
  		   router_ifinfo->bat_v.throughput % 10, router->addr,
  		   router->if_incoming->net_dev->name,
  		   gw_node->bandwidth_down / 10,
  		   gw_node->bandwidth_down % 10,
  		   gw_node->bandwidth_up / 10,
  		   gw_node->bandwidth_up % 10);
  	ret = seq_has_overflowed(seq) ? -1 : 0;
  
  	if (curr_gw)
  		batadv_gw_node_put(curr_gw);
  out:
  	if (router_ifinfo)
  		batadv_neigh_ifinfo_put(router_ifinfo);
  	if (router)
  		batadv_neigh_node_put(router);
  	return ret;
  }
  
  /**
   * batadv_v_gw_print - print the gateway list
   * @bat_priv: the bat priv with all the soft interface information
   * @seq: gateway table seq_file struct
   */
  static void batadv_v_gw_print(struct batadv_priv *bat_priv,
  			      struct seq_file *seq)
  {
  	struct batadv_gw_node *gw_node;
  	int gw_count = 0;
  
  	seq_puts(seq,
  		 "      Gateway        ( throughput)           Nexthop [outgoingIF]: advertised uplink bandwidth
  ");
  
  	rcu_read_lock();

  	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {

  		/* fails if orig_node has no router */
  		if (batadv_v_gw_write_buffer_text(bat_priv, seq, gw_node) < 0)
  			continue;
  
  		gw_count++;
  	}
  	rcu_read_unlock();
  
  	if (gw_count == 0)
  		seq_puts(seq, "No gateways in range ...
  ");
  }

  #endif

  /**
   * batadv_v_gw_dump_entry - Dump a gateway into a message
   * @msg: Netlink message to dump into
   * @portid: Port making netlink request
   * @seq: Sequence number of netlink message
   * @bat_priv: The bat priv with all the soft interface information
   * @gw_node: Gateway to be dumped
   *
   * Return: Error code, or 0 on success
   */
  static int batadv_v_gw_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
  				  struct batadv_priv *bat_priv,
  				  struct batadv_gw_node *gw_node)
  {
  	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
  	struct batadv_neigh_node *router;

  	struct batadv_gw_node *curr_gw = NULL;

  	int ret = 0;

  	void *hdr;
  
  	router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
  	if (!router)
  		goto out;
  
  	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
  	if (!router_ifinfo)
  		goto out;
  
  	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
  			  NLM_F_MULTI, BATADV_CMD_GET_GATEWAYS);
  	if (!hdr) {
  		ret = -ENOBUFS;
  		goto out;
  	}
  
  	ret = -EMSGSIZE;
  
  	if (curr_gw == gw_node) {
  		if (nla_put_flag(msg, BATADV_ATTR_FLAG_BEST)) {
  			genlmsg_cancel(msg, hdr);
  			goto out;
  		}
  	}
  
  	if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
  		    gw_node->orig_node->orig)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	if (nla_put_u32(msg, BATADV_ATTR_THROUGHPUT,
  			router_ifinfo->bat_v.throughput)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	if (nla_put(msg, BATADV_ATTR_ROUTER, ETH_ALEN, router->addr)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	if (nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
  			   router->if_incoming->net_dev->name)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	if (nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_DOWN,
  			gw_node->bandwidth_down)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	if (nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_UP, gw_node->bandwidth_up)) {
  		genlmsg_cancel(msg, hdr);
  		goto out;
  	}
  
  	genlmsg_end(msg, hdr);
  	ret = 0;
  
  out:

  	if (curr_gw)
  		batadv_gw_node_put(curr_gw);

  	if (router_ifinfo)
  		batadv_neigh_ifinfo_put(router_ifinfo);
  	if (router)
  		batadv_neigh_node_put(router);
  	return ret;
  }
  
  /**
   * batadv_v_gw_dump - Dump gateways into a message
   * @msg: Netlink message to dump into
   * @cb: Control block containing additional options
   * @bat_priv: The bat priv with all the soft interface information
   */
  static void batadv_v_gw_dump(struct sk_buff *msg, struct netlink_callback *cb,
  			     struct batadv_priv *bat_priv)
  {
  	int portid = NETLINK_CB(cb->skb).portid;
  	struct batadv_gw_node *gw_node;
  	int idx_skip = cb->args[0];
  	int idx = 0;
  
  	rcu_read_lock();

  	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {

  		if (idx++ < idx_skip)
  			continue;
  
  		if (batadv_v_gw_dump_entry(msg, portid, cb->nlh->nlmsg_seq,
  					   bat_priv, gw_node)) {
  			idx_skip = idx - 1;
  			goto unlock;
  		}
  	}
  
  	idx_skip = idx;
  unlock:
  	rcu_read_unlock();
  
  	cb->args[0] = idx_skip;
  }

  static struct batadv_algo_ops batadv_batman_v __read_mostly = {
  	.name = "BATMAN_V",

  	.iface = {
  		.activate = batadv_v_iface_activate,
  		.enable = batadv_v_iface_enable,
  		.disable = batadv_v_iface_disable,
  		.update_mac = batadv_v_iface_update_mac,
  		.primary_set = batadv_v_primary_iface_set,
  	},
  	.neigh = {
  		.hardif_init = batadv_v_hardif_neigh_init,
  		.cmp = batadv_v_neigh_cmp,
  		.is_similar_or_better = batadv_v_neigh_is_sob,

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  		.print = batadv_v_neigh_print,

  #endif

  		.dump = batadv_v_neigh_dump,

  	},
  	.orig = {

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  		.print = batadv_v_orig_print,

  #endif

  		.dump = batadv_v_orig_dump,

  	},

  	.gw = {

  		.init_sel_class = batadv_v_init_sel_class,

  		.store_sel_class = batadv_v_store_sel_class,
  		.show_sel_class = batadv_v_show_sel_class,

  		.get_best_gw_node = batadv_v_gw_get_best_gw_node,
  		.is_eligible = batadv_v_gw_is_eligible,

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  		.print = batadv_v_gw_print,

  #endif

  		.dump = batadv_v_gw_dump,

  	},

  };
  
  /**

   * batadv_v_hardif_init - initialize the algorithm specific fields in the
   *  hard-interface object
   * @hard_iface: the hard-interface to initialize
   */
  void batadv_v_hardif_init(struct batadv_hard_iface *hard_iface)
  {
  	/* enable link throughput auto-detection by setting the throughput
  	 * override to zero
  	 */
  	atomic_set(&hard_iface->bat_v.throughput_override, 0);
  	atomic_set(&hard_iface->bat_v.elp_interval, 500);
  }
  
  /**

   * batadv_v_mesh_init - initialize the B.A.T.M.A.N. V private resources for a
   *  mesh
   * @bat_priv: the object representing the mesh interface to initialise
   *
   * Return: 0 on success or a negative error code otherwise
   */
  int batadv_v_mesh_init(struct batadv_priv *bat_priv)
  {

  	int ret = 0;
  
  	ret = batadv_v_ogm_init(bat_priv);
  	if (ret < 0)
  		return ret;

  	return 0;

  }
  
  /**
   * batadv_v_mesh_free - free the B.A.T.M.A.N. V private resources for a mesh
   * @bat_priv: the object representing the mesh interface to free
   */
  void batadv_v_mesh_free(struct batadv_priv *bat_priv)
  {
  	batadv_v_ogm_free(bat_priv);
  }
  
  /**

   * batadv_v_init - B.A.T.M.A.N. V initialization function
   *
   * Description: Takes care of initializing all the subcomponents.
   * It is invoked upon module load only.
   *
   * Return: 0 on success or a negative error code otherwise
   */
  int __init batadv_v_init(void)
  {

  	int ret;
  
  	/* B.A.T.M.A.N. V echo location protocol packet  */
  	ret = batadv_recv_handler_register(BATADV_ELP,
  					   batadv_v_elp_packet_recv);
  	if (ret < 0)
  		return ret;

  	ret = batadv_recv_handler_register(BATADV_OGM2,
  					   batadv_v_ogm_packet_recv);
  	if (ret < 0)
  		goto elp_unregister;

  	ret = batadv_algo_register(&batadv_batman_v);

  	if (ret < 0)

  		goto ogm_unregister;
  
  	return ret;
  
  ogm_unregister:
  	batadv_recv_handler_unregister(BATADV_OGM2);
  
  elp_unregister:
  	batadv_recv_handler_unregister(BATADV_ELP);

  
  	return ret;

  }