/* Copyright (C) 2007-2013 B.A.T.M.A.N. contributors:

   *
   * Marek Lindner, Simon Wunderlich
   *
   * 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 "main.h"

  #include "distributed-arp-table.h"

  #include "send.h"
  #include "routing.h"
  #include "translation-table.h"
  #include "soft-interface.h"
  #include "hard-interface.h"

  #include "vis.h"

  #include "gateway_common.h"
  #include "originator.h"

  #include "network-coding.h"

  #include <linux/if_ether.h>

  static void batadv_send_outstanding_bcast_packet(struct work_struct *work);

  /* send out an already prepared packet to the given address via the

   * specified batman interface
   */

  int batadv_send_skb_packet(struct sk_buff *skb,
  			   struct batadv_hard_iface *hard_iface,

  			   const uint8_t *dst_addr)

  {

  	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);

  	struct ethhdr *ethhdr;

  	if (hard_iface->if_status != BATADV_IF_ACTIVE)

  		goto send_skb_err;

  	if (unlikely(!hard_iface->net_dev))

  		goto send_skb_err;

  	if (!(hard_iface->net_dev->flags & IFF_UP)) {

  		pr_warn("Interface %s is not up - can't send packet via that interface!
  ",
  			hard_iface->net_dev->name);

  		goto send_skb_err;
  	}
  
  	/* push to the ethernet header. */

  	if (batadv_skb_head_push(skb, ETH_HLEN) < 0)

  		goto send_skb_err;
  
  	skb_reset_mac_header(skb);

  	ethhdr = (struct ethhdr *)skb_mac_header(skb);

  	memcpy(ethhdr->h_source, hard_iface->net_dev->dev_addr, ETH_ALEN);

  	memcpy(ethhdr->h_dest, dst_addr, ETH_ALEN);

  	ethhdr->h_proto = __constant_htons(ETH_P_BATMAN);

  
  	skb_set_network_header(skb, ETH_HLEN);
  	skb->priority = TC_PRIO_CONTROL;

  	skb->protocol = __constant_htons(ETH_P_BATMAN);

  	skb->dev = hard_iface->net_dev;

  	/* Save a clone of the skb to use when decoding coded packets */
  	batadv_nc_skb_store_for_decoding(bat_priv, skb);

  	/* dev_queue_xmit() returns a negative result on error.	 However on
  	 * congestion and traffic shaping, it drops and returns NET_XMIT_DROP

  	 * (which is > 0). This will not be treated as an error.
  	 */

  	return dev_queue_xmit(skb);
  send_skb_err:
  	kfree_skb(skb);
  	return NET_XMIT_DROP;
  }

  /**
   * batadv_send_skb_to_orig - Lookup next-hop and transmit skb.
   * @skb: Packet to be transmitted.
   * @orig_node: Final destination of the packet.
   * @recv_if: Interface used when receiving the packet (can be NULL).
   *
   * Looks up the best next-hop towards the passed originator and passes the
   * skb on for preparation of MAC header. If the packet originated from this
   * host, NULL can be passed as recv_if and no interface alternating is
   * attempted.
   *
   * Returns TRUE on success; FALSE otherwise.
   */
  bool batadv_send_skb_to_orig(struct sk_buff *skb,
  			     struct batadv_orig_node *orig_node,
  			     struct batadv_hard_iface *recv_if)
  {
  	struct batadv_priv *bat_priv = orig_node->bat_priv;
  	struct batadv_neigh_node *neigh_node;
  
  	/* batadv_find_router() increases neigh_nodes refcount if found. */
  	neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
  	if (!neigh_node)
  		return false;
  
  	/* route it */
  	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
  
  	batadv_neigh_node_free_ref(neigh_node);
  
  	return true;
  }

  void batadv_schedule_bat_ogm(struct batadv_hard_iface *hard_iface)

  {

  	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);

  	if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
  	    (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))

  		return;

  	/* the interface gets activated here to avoid race conditions between

  	 * the moment of activating the interface in
  	 * hardif_activate_interface() where the originator mac is set and
  	 * outdated packets (especially uninitialized mac addresses) in the
  	 * packet queue
  	 */

  	if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
  		hard_iface->if_status = BATADV_IF_ACTIVE;

  	bat_priv->bat_algo_ops->bat_ogm_schedule(hard_iface);

  }

  static void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet)

  {
  	if (forw_packet->skb)
  		kfree_skb(forw_packet->skb);

  	if (forw_packet->if_incoming)

  		batadv_hardif_free_ref(forw_packet->if_incoming);

  	kfree(forw_packet);
  }

  static void
  _batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,
  				 struct batadv_forw_packet *forw_packet,
  				 unsigned long send_time)

  {
  	INIT_HLIST_NODE(&forw_packet->list);
  
  	/* add new packet to packet list */
  	spin_lock_bh(&bat_priv->forw_bcast_list_lock);
  	hlist_add_head(&forw_packet->list, &bat_priv->forw_bcast_list);
  	spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
  
  	/* start timer for this packet */

  	queue_delayed_work(batadv_event_workqueue, &forw_packet->delayed_work,

  			   send_time);
  }

  /* add a broadcast packet to the queue and setup timers. broadcast packets

   * are sent multiple times to increase probability for being received.

   *
   * This function returns NETDEV_TX_OK on success and NETDEV_TX_BUSY on
   * errors.
   *
   * The skb is not consumed, so the caller should make sure that the

   * skb is freed.
   */

  int batadv_add_bcast_packet_to_list(struct batadv_priv *bat_priv,

  				    const struct sk_buff *skb,
  				    unsigned long delay)

  {

  	struct batadv_hard_iface *primary_if = NULL;
  	struct batadv_forw_packet *forw_packet;

  	struct batadv_bcast_packet *bcast_packet;

  	struct sk_buff *newskb;

  	if (!batadv_atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {

  		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
  			   "bcast packet queue full
  ");

  		goto out;
  	}

  	primary_if = batadv_primary_if_get_selected(bat_priv);

  	if (!primary_if)

  		goto out_and_inc;

  	forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);

  
  	if (!forw_packet)
  		goto out_and_inc;

  	newskb = skb_copy(skb, GFP_ATOMIC);
  	if (!newskb)

  		goto packet_free;
  
  	/* as we have a copy now, it is safe to decrease the TTL */

  	bcast_packet = (struct batadv_bcast_packet *)newskb->data;

  	bcast_packet->header.ttl--;

  	skb_reset_mac_header(newskb);

  	forw_packet->skb = newskb;

  	forw_packet->if_incoming = primary_if;

  
  	/* how often did we send the bcast packet ? */
  	forw_packet->num_packets = 0;

  	INIT_DELAYED_WORK(&forw_packet->delayed_work,
  			  batadv_send_outstanding_bcast_packet);

  	_batadv_add_bcast_packet_to_list(bat_priv, forw_packet, delay);

  	return NETDEV_TX_OK;
  
  packet_free:
  	kfree(forw_packet);
  out_and_inc:
  	atomic_inc(&bat_priv->bcast_queue_left);
  out:

  	if (primary_if)

  		batadv_hardif_free_ref(primary_if);

  	return NETDEV_TX_BUSY;
  }

  static void batadv_send_outstanding_bcast_packet(struct work_struct *work)

  {

  	struct batadv_hard_iface *hard_iface;

  	struct delayed_work *delayed_work;

  	struct batadv_forw_packet *forw_packet;

  	struct sk_buff *skb1;

  	struct net_device *soft_iface;
  	struct batadv_priv *bat_priv;

  	delayed_work = container_of(work, struct delayed_work, work);

  	forw_packet = container_of(delayed_work, struct batadv_forw_packet,
  				   delayed_work);
  	soft_iface = forw_packet->if_incoming->soft_iface;
  	bat_priv = netdev_priv(soft_iface);

  
  	spin_lock_bh(&bat_priv->forw_bcast_list_lock);
  	hlist_del(&forw_packet->list);
  	spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

  	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)

  		goto out;

  	if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
  		goto out;

  	/* rebroadcast packet */
  	rcu_read_lock();

  	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {

  		if (hard_iface->soft_iface != soft_iface)

  			continue;
  
  		/* send a copy of the saved skb */
  		skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
  		if (skb1)

  			batadv_send_skb_packet(skb1, hard_iface,

  					       batadv_broadcast_addr);

  	}
  	rcu_read_unlock();
  
  	forw_packet->num_packets++;
  
  	/* if we still have some more bcasts to send */
  	if (forw_packet->num_packets < 3) {

  		_batadv_add_bcast_packet_to_list(bat_priv, forw_packet,
  						 msecs_to_jiffies(5));

  		return;
  	}
  
  out:

  	batadv_forw_packet_free(forw_packet);

  	atomic_inc(&bat_priv->bcast_queue_left);
  }

  void batadv_send_outstanding_bat_ogm_packet(struct work_struct *work)

  {

  	struct delayed_work *delayed_work;

  	struct batadv_forw_packet *forw_packet;
  	struct batadv_priv *bat_priv;

  	delayed_work = container_of(work, struct delayed_work, work);

  	forw_packet = container_of(delayed_work, struct batadv_forw_packet,
  				   delayed_work);

  	bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
  	spin_lock_bh(&bat_priv->forw_bat_list_lock);
  	hlist_del(&forw_packet->list);
  	spin_unlock_bh(&bat_priv->forw_bat_list_lock);

  	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)

  		goto out;

  	bat_priv->bat_algo_ops->bat_ogm_emit(forw_packet);

  	/* we have to have at least one packet in the queue

  	 * to determine the queues wake up time unless we are
  	 * shutting down
  	 */
  	if (forw_packet->own)

  		batadv_schedule_bat_ogm(forw_packet->if_incoming);

  
  out:
  	/* don't count own packet */
  	if (!forw_packet->own)
  		atomic_inc(&bat_priv->batman_queue_left);

  	batadv_forw_packet_free(forw_packet);

  }

  void
  batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
  				 const struct batadv_hard_iface *hard_iface)

  {

  	struct batadv_forw_packet *forw_packet;

  	struct hlist_node *safe_tmp_node;

  	bool pending;

  	if (hard_iface)

  		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,

  			   "purge_outstanding_packets(): %s
  ",
  			   hard_iface->net_dev->name);

  	else

  		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,

  			   "purge_outstanding_packets()
  ");

  
  	/* free bcast list */
  	spin_lock_bh(&bat_priv->forw_bcast_list_lock);

  	hlist_for_each_entry_safe(forw_packet, safe_tmp_node,

  				  &bat_priv->forw_bcast_list, list) {

  		/* if purge_outstanding_packets() was called with an argument

  		 * we delete only packets belonging to the given interface
  		 */

  		if ((hard_iface) &&
  		    (forw_packet->if_incoming != hard_iface))

  			continue;
  
  		spin_unlock_bh(&bat_priv->forw_bcast_list_lock);

  		/* batadv_send_outstanding_bcast_packet() will lock the list to

  		 * delete the item from the list
  		 */

  		pending = cancel_delayed_work_sync(&forw_packet->delayed_work);

  		spin_lock_bh(&bat_priv->forw_bcast_list_lock);

  
  		if (pending) {
  			hlist_del(&forw_packet->list);

  			batadv_forw_packet_free(forw_packet);

  		}

  	}
  	spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
  
  	/* free batman packet list */
  	spin_lock_bh(&bat_priv->forw_bat_list_lock);

  	hlist_for_each_entry_safe(forw_packet, safe_tmp_node,

  				  &bat_priv->forw_bat_list, list) {

  		/* if purge_outstanding_packets() was called with an argument

  		 * we delete only packets belonging to the given interface
  		 */

  		if ((hard_iface) &&
  		    (forw_packet->if_incoming != hard_iface))

  			continue;
  
  		spin_unlock_bh(&bat_priv->forw_bat_list_lock);

  		/* send_outstanding_bat_packet() will lock the list to

  		 * delete the item from the list
  		 */

  		pending = cancel_delayed_work_sync(&forw_packet->delayed_work);

  		spin_lock_bh(&bat_priv->forw_bat_list_lock);

  
  		if (pending) {
  			hlist_del(&forw_packet->list);

  			batadv_forw_packet_free(forw_packet);

  		}

  	}
  	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
  }