/*

   * Copyright (C) 2007-2011 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 "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 "bat_ogm.h"

  
  static void send_outstanding_bcast_packet(struct work_struct *work);

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

  int send_skb_packet(struct sk_buff *skb, struct hard_iface *hard_iface,
  		    const uint8_t *dst_addr)

  {
  	struct ethhdr *ethhdr;

  	if (hard_iface->if_status != 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_warning("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 (my_skb_head_push(skb, sizeof(*ethhdr)) < 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;

  
  	/* 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;
  }

  static void realloc_packet_buffer(struct hard_iface *hard_iface,

  				  int new_len)

  {

  	unsigned char *new_buff;

  	new_buff = kmalloc(new_len, GFP_ATOMIC);
  
  	/* keep old buffer if kmalloc should fail */
  	if (new_buff) {

  		memcpy(new_buff, hard_iface->packet_buff,

  		       BATMAN_OGM_LEN);

  		kfree(hard_iface->packet_buff);
  		hard_iface->packet_buff = new_buff;
  		hard_iface->packet_len = new_len;

  	}
  }

  /* when calling this function (hard_iface == primary_if) has to be true */

  static int prepare_packet_buffer(struct bat_priv *bat_priv,

  				  struct hard_iface *hard_iface)
  {
  	int new_len;

  	new_len = BATMAN_OGM_LEN +

  		  tt_len((uint8_t)atomic_read(&bat_priv->tt_local_changes));
  
  	/* if we have too many changes for one packet don't send any
  	 * and wait for the tt table request which will be fragmented */
  	if (new_len > hard_iface->soft_iface->mtu)

  		new_len = BATMAN_OGM_LEN;

  
  	realloc_packet_buffer(hard_iface, new_len);

  
  	atomic_set(&bat_priv->tt_crc, tt_local_crc(bat_priv));
  
  	/* reset the sending counter */
  	atomic_set(&bat_priv->tt_ogm_append_cnt, TT_OGM_APPEND_MAX);

  	return tt_changes_fill_buffer(bat_priv,
  				      hard_iface->packet_buff + BATMAN_OGM_LEN,
  				      hard_iface->packet_len - BATMAN_OGM_LEN);

  }

  static int reset_packet_buffer(struct bat_priv *bat_priv,

  				struct hard_iface *hard_iface)

  {

  	realloc_packet_buffer(hard_iface, BATMAN_OGM_LEN);

  	return 0;

  }

  void schedule_bat_ogm(struct hard_iface *hard_iface)

  {

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

  	struct hard_iface *primary_if;

  	int tt_num_changes = -1;

  	if ((hard_iface->if_status == IF_NOT_IN_USE) ||
  	    (hard_iface->if_status == 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 == IF_TO_BE_ACTIVATED)
  		hard_iface->if_status = IF_ACTIVE;

  	primary_if = primary_if_get_selected(bat_priv);

  	if (hard_iface == primary_if) {
  		/* if at least one change happened */
  		if (atomic_read(&bat_priv->tt_local_changes) > 0) {

  			tt_commit_changes(bat_priv);

  			tt_num_changes = prepare_packet_buffer(bat_priv,
  							       hard_iface);

  		}

  		/* if the changes have been sent often enough */

  		if (!atomic_dec_not_zero(&bat_priv->tt_ogm_append_cnt))

  			tt_num_changes = reset_packet_buffer(bat_priv,
  							     hard_iface);

  	}

  	if (primary_if)
  		hardif_free_ref(primary_if);

  	bat_ogm_schedule(hard_iface, tt_num_changes);

  }
  
  static void forw_packet_free(struct forw_packet *forw_packet)
  {
  	if (forw_packet->skb)
  		kfree_skb(forw_packet->skb);

  	if (forw_packet->if_incoming)
  		hardif_free_ref(forw_packet->if_incoming);

  	kfree(forw_packet);
  }
  
  static void _add_bcast_packet_to_list(struct bat_priv *bat_priv,
  				      struct 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 */
  	INIT_DELAYED_WORK(&forw_packet->delayed_work,
  			  send_outstanding_bcast_packet);
  	queue_delayed_work(bat_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 add_bcast_packet_to_list(struct bat_priv *bat_priv,

  			     const struct sk_buff *skb, unsigned long delay)

  {

  	struct hard_iface *primary_if = NULL;

  	struct forw_packet *forw_packet;
  	struct bcast_packet *bcast_packet;

  	struct sk_buff *newskb;

  
  	if (!atomic_dec_not_zero(&bat_priv->bcast_queue_left)) {
  		bat_dbg(DBG_BATMAN, bat_priv, "bcast packet queue full
  ");
  		goto out;
  	}

  	primary_if = 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 bcast_packet *)newskb->data;

  	bcast_packet->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;

  	_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)
  		hardif_free_ref(primary_if);

  	return NETDEV_TX_BUSY;
  }
  
  static void send_outstanding_bcast_packet(struct work_struct *work)
  {

  	struct hard_iface *hard_iface;

  	struct delayed_work *delayed_work =
  		container_of(work, struct delayed_work, work);
  	struct forw_packet *forw_packet =
  		container_of(delayed_work, struct forw_packet, delayed_work);
  	struct sk_buff *skb1;
  	struct net_device *soft_iface = forw_packet->if_incoming->soft_iface;
  	struct bat_priv *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) == MESH_DEACTIVATING)
  		goto out;
  
  	/* rebroadcast packet */
  	rcu_read_lock();

  	list_for_each_entry_rcu(hard_iface, &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)

  			send_skb_packet(skb1, hard_iface, broadcast_addr);

  	}
  	rcu_read_unlock();
  
  	forw_packet->num_packets++;
  
  	/* if we still have some more bcasts to send */
  	if (forw_packet->num_packets < 3) {
  		_add_bcast_packet_to_list(bat_priv, forw_packet,
  					  ((5 * HZ) / 1000));
  		return;
  	}
  
  out:
  	forw_packet_free(forw_packet);
  	atomic_inc(&bat_priv->bcast_queue_left);
  }

  void send_outstanding_bat_ogm_packet(struct work_struct *work)

  {
  	struct delayed_work *delayed_work =
  		container_of(work, struct delayed_work, work);
  	struct forw_packet *forw_packet =
  		container_of(delayed_work, struct forw_packet, delayed_work);
  	struct bat_priv *bat_priv;
  
  	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) == MESH_DEACTIVATING)
  		goto out;

  	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)

  		schedule_bat_ogm(forw_packet->if_incoming);

  
  out:
  	/* don't count own packet */
  	if (!forw_packet->own)
  		atomic_inc(&bat_priv->batman_queue_left);
  
  	forw_packet_free(forw_packet);
  }
  
  void purge_outstanding_packets(struct bat_priv *bat_priv,

  			       const struct hard_iface *hard_iface)

  {
  	struct forw_packet *forw_packet;
  	struct hlist_node *tmp_node, *safe_tmp_node;

  	bool pending;

  	if (hard_iface)

  		bat_dbg(DBG_BATMAN, bat_priv,
  			"purge_outstanding_packets(): %s
  ",

  			hard_iface->net_dev->name);

  	else
  		bat_dbg(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, tmp_node, 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);
  
  		/**
  		 * 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);
  			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, tmp_node, 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);
  			forw_packet_free(forw_packet);
  		}

  	}
  	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
  }