/*

   * Copyright (C) 2008-2011 B.A.T.M.A.N. contributors:

   *
   * 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 "translation-table.h"
  #include "vis.h"
  #include "soft-interface.h"
  #include "hard-interface.h"
  #include "hash.h"
  #include "originator.h"
  
  #define MAX_VIS_PACKET_SIZE 1000

  static void start_vis_timer(struct bat_priv *bat_priv);
  
  /* free the info */
  static void free_info(struct kref *ref)
  {
  	struct vis_info *info = container_of(ref, struct vis_info, refcount);
  	struct bat_priv *bat_priv = info->bat_priv;
  	struct recvlist_node *entry, *tmp;
  
  	list_del_init(&info->send_list);
  	spin_lock_bh(&bat_priv->vis_list_lock);
  	list_for_each_entry_safe(entry, tmp, &info->recv_list, list) {
  		list_del(&entry->list);
  		kfree(entry);
  	}
  
  	spin_unlock_bh(&bat_priv->vis_list_lock);
  	kfree_skb(info->skb_packet);

  	kfree(info);

  }
  
  /* Compare two vis packets, used by the hashing algorithm */

  static int vis_info_cmp(const struct hlist_node *node, const void *data2)

  {

  	const struct vis_info *d1, *d2;
  	const struct vis_packet *p1, *p2;

  
  	d1 = container_of(node, struct vis_info, hash_entry);

  	d2 = data2;
  	p1 = (struct vis_packet *)d1->skb_packet->data;
  	p2 = (struct vis_packet *)d2->skb_packet->data;

  	return compare_eth(p1->vis_orig, p2->vis_orig);

  }
  
  /* hash function to choose an entry in a hash table of given size */
  /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */

  static uint32_t vis_info_choose(const void *data, uint32_t size)

  {

  	const struct vis_info *vis_info = data;
  	const struct vis_packet *packet;
  	const unsigned char *key;

  	uint32_t hash = 0;
  	size_t i;
  
  	packet = (struct vis_packet *)vis_info->skb_packet->data;
  	key = packet->vis_orig;
  	for (i = 0; i < ETH_ALEN; i++) {
  		hash += key[i];
  		hash += (hash << 10);
  		hash ^= (hash >> 6);
  	}
  
  	hash += (hash << 3);
  	hash ^= (hash >> 11);
  	hash += (hash << 15);
  
  	return hash % size;
  }

  static struct vis_info *vis_hash_find(struct bat_priv *bat_priv,

  				      const void *data)

  {
  	struct hashtable_t *hash = bat_priv->vis_hash;
  	struct hlist_head *head;
  	struct hlist_node *node;
  	struct vis_info *vis_info, *vis_info_tmp = NULL;

  	uint32_t index;

  
  	if (!hash)
  		return NULL;
  
  	index = vis_info_choose(data, hash->size);
  	head = &hash->table[index];
  
  	rcu_read_lock();
  	hlist_for_each_entry_rcu(vis_info, node, head, hash_entry) {
  		if (!vis_info_cmp(node, data))
  			continue;
  
  		vis_info_tmp = vis_info;
  		break;
  	}
  	rcu_read_unlock();
  
  	return vis_info_tmp;
  }

  /* insert interface to the list of interfaces of one originator, if it
   * does not already exist in the list */
  static void vis_data_insert_interface(const uint8_t *interface,
  				      struct hlist_head *if_list,
  				      bool primary)
  {
  	struct if_list_entry *entry;
  	struct hlist_node *pos;
  
  	hlist_for_each_entry(entry, pos, if_list, list) {

  		if (compare_eth(entry->addr, interface))

  			return;
  	}

  	/* it's a new address, add it to the list */

  	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
  	if (!entry)
  		return;
  	memcpy(entry->addr, interface, ETH_ALEN);
  	entry->primary = primary;
  	hlist_add_head(&entry->list, if_list);
  }

  static ssize_t vis_data_read_prim_sec(char *buff,
  				      const struct hlist_head *if_list)

  {
  	struct if_list_entry *entry;
  	struct hlist_node *pos;
  	size_t len = 0;
  
  	hlist_for_each_entry(entry, pos, if_list, list) {
  		if (entry->primary)
  			len += sprintf(buff + len, "PRIMARY, ");
  		else
  			len += sprintf(buff + len,  "SEC %pM, ", entry->addr);
  	}
  
  	return len;
  }
  
  static size_t vis_data_count_prim_sec(struct hlist_head *if_list)
  {
  	struct if_list_entry *entry;
  	struct hlist_node *pos;
  	size_t count = 0;
  
  	hlist_for_each_entry(entry, pos, if_list, list) {
  		if (entry->primary)
  			count += 9;
  		else
  			count += 23;
  	}
  
  	return count;
  }
  
  /* read an entry  */

  static ssize_t vis_data_read_entry(char *buff,
  				   const struct vis_info_entry *entry,
  				   const uint8_t *src, bool primary)

  {
  	/* maximal length: max(4+17+2, 3+17+1+3+2) == 26 */
  	if (primary && entry->quality == 0)

  		return sprintf(buff, "TT %pM, ", entry->dest);

  	else if (compare_eth(entry->src, src))

  		return sprintf(buff, "TQ %pM %d, ", entry->dest,
  			       entry->quality);
  
  	return 0;
  }
  
  int vis_seq_print_text(struct seq_file *seq, void *offset)
  {

  	struct hard_iface *primary_if;

  	struct hlist_node *node;

  	struct hlist_head *head;

  	struct vis_info *info;
  	struct vis_packet *packet;
  	struct vis_info_entry *entries;
  	struct net_device *net_dev = (struct net_device *)seq->private;
  	struct bat_priv *bat_priv = netdev_priv(net_dev);
  	struct hashtable_t *hash = bat_priv->vis_hash;
  	HLIST_HEAD(vis_if_list);
  	struct if_list_entry *entry;
  	struct hlist_node *pos, *n;

  	uint32_t i;
  	int j, ret = 0;

  	int vis_server = atomic_read(&bat_priv->vis_mode);
  	size_t buff_pos, buf_size;
  	char *buff;
  	int compare;

  	primary_if = primary_if_get_selected(bat_priv);
  	if (!primary_if)
  		goto out;
  
  	if (vis_server == VIS_TYPE_CLIENT_UPDATE)
  		goto out;

  
  	buf_size = 1;
  	/* Estimate length */
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();
  		hlist_for_each_entry_rcu(info, node, head, hash_entry) {

  			packet = (struct vis_packet *)info->skb_packet->data;
  			entries = (struct vis_info_entry *)

  				((char *)packet + sizeof(*packet));

  
  			for (j = 0; j < packet->entries; j++) {
  				if (entries[j].quality == 0)
  					continue;
  				compare =

  				 compare_eth(entries[j].src, packet->vis_orig);

  				vis_data_insert_interface(entries[j].src,
  							  &vis_if_list,
  							  compare);
  			}
  
  			hlist_for_each_entry(entry, pos, &vis_if_list, list) {
  				buf_size += 18 + 26 * packet->entries;
  
  				/* add primary/secondary records */

  				if (compare_eth(entry->addr, packet->vis_orig))

  					buf_size +=
  					  vis_data_count_prim_sec(&vis_if_list);
  
  				buf_size += 1;
  			}
  
  			hlist_for_each_entry_safe(entry, pos, n, &vis_if_list,
  						  list) {
  				hlist_del(&entry->list);
  				kfree(entry);
  			}
  		}

  		rcu_read_unlock();

  	}
  
  	buff = kmalloc(buf_size, GFP_ATOMIC);
  	if (!buff) {
  		spin_unlock_bh(&bat_priv->vis_hash_lock);

  		ret = -ENOMEM;
  		goto out;

  	}
  	buff[0] = '\0';
  	buff_pos = 0;
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();
  		hlist_for_each_entry_rcu(info, node, head, hash_entry) {

  			packet = (struct vis_packet *)info->skb_packet->data;
  			entries = (struct vis_info_entry *)

  				((char *)packet + sizeof(*packet));

  
  			for (j = 0; j < packet->entries; j++) {
  				if (entries[j].quality == 0)
  					continue;
  				compare =

  				 compare_eth(entries[j].src, packet->vis_orig);

  				vis_data_insert_interface(entries[j].src,
  							  &vis_if_list,
  							  compare);
  			}
  
  			hlist_for_each_entry(entry, pos, &vis_if_list, list) {
  				buff_pos += sprintf(buff + buff_pos, "%pM,",
  						entry->addr);

  				for (j = 0; j < packet->entries; j++)

  					buff_pos += vis_data_read_entry(
  							buff + buff_pos,

  							&entries[j],

  							entry->addr,
  							entry->primary);
  
  				/* add primary/secondary records */

  				if (compare_eth(entry->addr, packet->vis_orig))

  					buff_pos +=
  					 vis_data_read_prim_sec(buff + buff_pos,
  								&vis_if_list);
  
  				buff_pos += sprintf(buff + buff_pos, "
  ");
  			}
  
  			hlist_for_each_entry_safe(entry, pos, n, &vis_if_list,
  						  list) {
  				hlist_del(&entry->list);
  				kfree(entry);
  			}
  		}

  		rcu_read_unlock();

  	}
  
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  
  	seq_printf(seq, "%s", buff);
  	kfree(buff);

  out:
  	if (primary_if)
  		hardif_free_ref(primary_if);
  	return ret;

  }
  
  /* add the info packet to the send list, if it was not
   * already linked in. */
  static void send_list_add(struct bat_priv *bat_priv, struct vis_info *info)
  {
  	if (list_empty(&info->send_list)) {
  		kref_get(&info->refcount);
  		list_add_tail(&info->send_list, &bat_priv->vis_send_list);
  	}
  }
  
  /* delete the info packet from the send list, if it was
   * linked in. */
  static void send_list_del(struct vis_info *info)
  {
  	if (!list_empty(&info->send_list)) {
  		list_del_init(&info->send_list);
  		kref_put(&info->refcount, free_info);
  	}
  }
  
  /* tries to add one entry to the receive list. */
  static void recv_list_add(struct bat_priv *bat_priv,

  			  struct list_head *recv_list, const char *mac)

  {
  	struct recvlist_node *entry;

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

  	if (!entry)
  		return;
  
  	memcpy(entry->mac, mac, ETH_ALEN);
  	spin_lock_bh(&bat_priv->vis_list_lock);
  	list_add_tail(&entry->list, recv_list);
  	spin_unlock_bh(&bat_priv->vis_list_lock);
  }
  
  /* returns 1 if this mac is in the recv_list */
  static int recv_list_is_in(struct bat_priv *bat_priv,

  			   const struct list_head *recv_list, const char *mac)

  {

  	const struct recvlist_node *entry;

  
  	spin_lock_bh(&bat_priv->vis_list_lock);
  	list_for_each_entry(entry, recv_list, list) {

  		if (compare_eth(entry->mac, mac)) {

  			spin_unlock_bh(&bat_priv->vis_list_lock);
  			return 1;
  		}
  	}
  	spin_unlock_bh(&bat_priv->vis_list_lock);
  	return 0;
  }
  
  /* try to add the packet to the vis_hash. return NULL if invalid (e.g. too old,
   * broken.. ).	vis hash must be locked outside.  is_new is set when the packet
   * is newer than old entries in the hash. */
  static struct vis_info *add_packet(struct bat_priv *bat_priv,
  				   struct vis_packet *vis_packet,
  				   int vis_info_len, int *is_new,
  				   int make_broadcast)
  {
  	struct vis_info *info, *old_info;
  	struct vis_packet *search_packet, *old_packet;
  	struct vis_info search_elem;
  	struct vis_packet *packet;
  	int hash_added;
  
  	*is_new = 0;
  	/* sanity check */
  	if (!bat_priv->vis_hash)
  		return NULL;
  
  	/* see if the packet is already in vis_hash */

  	search_elem.skb_packet = dev_alloc_skb(sizeof(*search_packet));

  	if (!search_elem.skb_packet)
  		return NULL;
  	search_packet = (struct vis_packet *)skb_put(search_elem.skb_packet,

  						     sizeof(*search_packet));

  
  	memcpy(search_packet->vis_orig, vis_packet->vis_orig, ETH_ALEN);

  	old_info = vis_hash_find(bat_priv, &search_elem);

  	kfree_skb(search_elem.skb_packet);
  
  	if (old_info) {
  		old_packet = (struct vis_packet *)old_info->skb_packet->data;
  		if (!seq_after(ntohl(vis_packet->seqno),
  			       ntohl(old_packet->seqno))) {
  			if (old_packet->seqno == vis_packet->seqno) {
  				recv_list_add(bat_priv, &old_info->recv_list,
  					      vis_packet->sender_orig);
  				return old_info;
  			} else {
  				/* newer packet is already in hash. */
  				return NULL;
  			}
  		}
  		/* remove old entry */
  		hash_remove(bat_priv->vis_hash, vis_info_cmp, vis_info_choose,
  			    old_info);
  		send_list_del(old_info);
  		kref_put(&old_info->refcount, free_info);
  	}

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

  	if (!info)
  		return NULL;

  	info->skb_packet = dev_alloc_skb(sizeof(*packet) + vis_info_len +
  					 sizeof(struct ethhdr));

  	if (!info->skb_packet) {
  		kfree(info);
  		return NULL;
  	}
  	skb_reserve(info->skb_packet, sizeof(struct ethhdr));

  	packet = (struct vis_packet *)skb_put(info->skb_packet, sizeof(*packet)
  					      + vis_info_len);

  
  	kref_init(&info->refcount);
  	INIT_LIST_HEAD(&info->send_list);
  	INIT_LIST_HEAD(&info->recv_list);
  	info->first_seen = jiffies;
  	info->bat_priv = bat_priv;

  	memcpy(packet, vis_packet, sizeof(*packet) + vis_info_len);

  
  	/* initialize and add new packet. */
  	*is_new = 1;
  
  	/* Make it a broadcast packet, if required */
  	if (make_broadcast)
  		memcpy(packet->target_orig, broadcast_addr, ETH_ALEN);
  
  	/* repair if entries is longer than packet. */
  	if (packet->entries * sizeof(struct vis_info_entry) > vis_info_len)
  		packet->entries = vis_info_len / sizeof(struct vis_info_entry);
  
  	recv_list_add(bat_priv, &info->recv_list, packet->sender_orig);
  
  	/* try to add it */
  	hash_added = hash_add(bat_priv->vis_hash, vis_info_cmp, vis_info_choose,

  			      info, &info->hash_entry);

  	if (hash_added != 0) {

  		/* did not work (for some reason) */

  		kref_put(&info->refcount, free_info);

  		info = NULL;
  	}
  
  	return info;
  }
  
  /* handle the server sync packet, forward if needed. */
  void receive_server_sync_packet(struct bat_priv *bat_priv,
  				struct vis_packet *vis_packet,
  				int vis_info_len)
  {
  	struct vis_info *info;
  	int is_new, make_broadcast;
  	int vis_server = atomic_read(&bat_priv->vis_mode);
  
  	make_broadcast = (vis_server == VIS_TYPE_SERVER_SYNC);
  
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  	info = add_packet(bat_priv, vis_packet, vis_info_len,
  			  &is_new, make_broadcast);
  	if (!info)
  		goto end;
  
  	/* only if we are server ourselves and packet is newer than the one in
  	 * hash.*/
  	if (vis_server == VIS_TYPE_SERVER_SYNC && is_new)
  		send_list_add(bat_priv, info);
  end:
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  }
  
  /* handle an incoming client update packet and schedule forward if needed. */
  void receive_client_update_packet(struct bat_priv *bat_priv,
  				  struct vis_packet *vis_packet,
  				  int vis_info_len)
  {
  	struct vis_info *info;
  	struct vis_packet *packet;
  	int is_new;
  	int vis_server = atomic_read(&bat_priv->vis_mode);
  	int are_target = 0;
  
  	/* clients shall not broadcast. */
  	if (is_broadcast_ether_addr(vis_packet->target_orig))
  		return;
  
  	/* Are we the target for this VIS packet? */
  	if (vis_server == VIS_TYPE_SERVER_SYNC	&&
  	    is_my_mac(vis_packet->target_orig))
  		are_target = 1;
  
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  	info = add_packet(bat_priv, vis_packet, vis_info_len,
  			  &is_new, are_target);
  
  	if (!info)
  		goto end;
  	/* note that outdated packets will be dropped at this point. */
  
  	packet = (struct vis_packet *)info->skb_packet->data;
  
  	/* send only if we're the target server or ... */
  	if (are_target && is_new) {
  		packet->vis_type = VIS_TYPE_SERVER_SYNC;	/* upgrade! */
  		send_list_add(bat_priv, info);
  
  		/* ... we're not the recipient (and thus need to forward). */
  	} else if (!is_my_mac(packet->target_orig)) {
  		send_list_add(bat_priv, info);
  	}
  
  end:
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  }
  
  /* Walk the originators and find the VIS server with the best tq. Set the packet
   * address to its address and return the best_tq.
   *
   * Must be called with the originator hash locked */
  static int find_best_vis_server(struct bat_priv *bat_priv,
  				struct vis_info *info)
  {
  	struct hashtable_t *hash = bat_priv->orig_hash;

  	struct neigh_node *router;

  	struct hlist_node *node;

  	struct hlist_head *head;

  	struct orig_node *orig_node;
  	struct vis_packet *packet;

  	int best_tq = -1;
  	uint32_t i;

  
  	packet = (struct vis_packet *)info->skb_packet->data;
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();

  		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {

  			router = orig_node_get_router(orig_node);
  			if (!router)
  				continue;
  
  			if ((orig_node->flags & VIS_SERVER) &&
  			    (router->tq_avg > best_tq)) {
  				best_tq = router->tq_avg;

  				memcpy(packet->target_orig, orig_node->orig,
  				       ETH_ALEN);
  			}

  			neigh_node_free_ref(router);

  		}

  		rcu_read_unlock();

  	}
  
  	return best_tq;
  }
  
  /* Return true if the vis packet is full. */

  static bool vis_packet_full(const struct vis_info *info)

  {

  	const struct vis_packet *packet;

  	packet = (struct vis_packet *)info->skb_packet->data;
  
  	if (MAX_VIS_PACKET_SIZE / sizeof(struct vis_info_entry)
  		< packet->entries + 1)
  		return true;
  	return false;
  }
  
  /* generates a packet of own vis data,
   * returns 0 on success, -1 if no packet could be generated */
  static int generate_vis_packet(struct bat_priv *bat_priv)
  {
  	struct hashtable_t *hash = bat_priv->orig_hash;

  	struct hlist_node *node;

  	struct hlist_head *head;

  	struct orig_node *orig_node;

  	struct neigh_node *router;

  	struct vis_info *info = bat_priv->my_vis_info;

  	struct vis_packet *packet = (struct vis_packet *)info->skb_packet->data;
  	struct vis_info_entry *entry;

  	struct tt_common_entry *tt_common_entry;

  	int best_tq = -1;
  	uint32_t i;

  
  	info->first_seen = jiffies;
  	packet->vis_type = atomic_read(&bat_priv->vis_mode);

  	memcpy(packet->target_orig, broadcast_addr, ETH_ALEN);
  	packet->ttl = TTL;
  	packet->seqno = htonl(ntohl(packet->seqno) + 1);
  	packet->entries = 0;

  	skb_trim(info->skb_packet, sizeof(*packet));

  
  	if (packet->vis_type == VIS_TYPE_CLIENT_UPDATE) {
  		best_tq = find_best_vis_server(bat_priv, info);

  		if (best_tq < 0)

  			return -1;

  	}
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();

  		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {

  			router = orig_node_get_router(orig_node);
  			if (!router)

  				continue;

  			if (!compare_eth(router->addr, orig_node->orig))
  				goto next;

  			if (router->if_incoming->if_status != IF_ACTIVE)
  				goto next;

  			if (router->tq_avg < 1)
  				goto next;

  
  			/* fill one entry into buffer. */
  			entry = (struct vis_info_entry *)
  				      skb_put(info->skb_packet, sizeof(*entry));
  			memcpy(entry->src,

  			       router->if_incoming->net_dev->dev_addr,

  			       ETH_ALEN);
  			memcpy(entry->dest, orig_node->orig, ETH_ALEN);

  			entry->quality = router->tq_avg;

  			packet->entries++;

  next:
  			neigh_node_free_ref(router);

  			if (vis_packet_full(info))
  				goto unlock;

  		}

  		rcu_read_unlock();

  	}

  	hash = bat_priv->tt_local_hash;

  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();

  		hlist_for_each_entry_rcu(tt_common_entry, node, head,

  					 hash_entry) {

  			entry = (struct vis_info_entry *)
  					skb_put(info->skb_packet,
  						sizeof(*entry));
  			memset(entry->src, 0, ETH_ALEN);

  			memcpy(entry->dest, tt_common_entry->addr, ETH_ALEN);

  			entry->quality = 0; /* 0 means TT */

  			packet->entries++;

  			if (vis_packet_full(info))
  				goto unlock;

  		}

  		rcu_read_unlock();

  	}

  	return 0;

  
  unlock:
  	rcu_read_unlock();
  	return 0;

  }
  
  /* free old vis packets. Must be called with this vis_hash_lock
   * held */
  static void purge_vis_packets(struct bat_priv *bat_priv)
  {

  	uint32_t i;

  	struct hashtable_t *hash = bat_priv->vis_hash;

  	struct hlist_node *node, *node_tmp;

  	struct hlist_head *head;

  	struct vis_info *info;
  
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		hlist_for_each_entry_safe(info, node, node_tmp,
  					  head, hash_entry) {

  			/* never purge own data. */
  			if (info == bat_priv->my_vis_info)
  				continue;
  
  			if (time_after(jiffies,
  				       info->first_seen + VIS_TIMEOUT * HZ)) {

  				hlist_del(node);

  				send_list_del(info);
  				kref_put(&info->refcount, free_info);
  			}
  		}
  	}
  }
  
  static void broadcast_vis_packet(struct bat_priv *bat_priv,
  				 struct vis_info *info)
  {

  	struct neigh_node *router;

  	struct hashtable_t *hash = bat_priv->orig_hash;

  	struct hlist_node *node;

  	struct hlist_head *head;

  	struct orig_node *orig_node;
  	struct vis_packet *packet;
  	struct sk_buff *skb;

  	struct hard_iface *hard_iface;

  	uint8_t dstaddr[ETH_ALEN];

  	uint32_t i;

  	packet = (struct vis_packet *)info->skb_packet->data;
  
  	/* send to all routers in range. */
  	for (i = 0; i < hash->size; i++) {
  		head = &hash->table[i];

  		rcu_read_lock();

  		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {

  			/* if it's a vis server and reachable, send it. */

  			if (!(orig_node->flags & VIS_SERVER))
  				continue;

  
  			router = orig_node_get_router(orig_node);
  			if (!router)
  				continue;

  			/* don't send it if we already received the packet from

  			 * this node. */

  			if (recv_list_is_in(bat_priv, &info->recv_list,

  					    orig_node->orig)) {
  				neigh_node_free_ref(router);

  				continue;

  			}

  
  			memcpy(packet->target_orig, orig_node->orig, ETH_ALEN);

  			hard_iface = router->if_incoming;
  			memcpy(dstaddr, router->addr, ETH_ALEN);
  
  			neigh_node_free_ref(router);

  
  			skb = skb_clone(info->skb_packet, GFP_ATOMIC);
  			if (skb)

  				send_skb_packet(skb, hard_iface, dstaddr);

  		}

  		rcu_read_unlock();

  	}

  }
  
  static void unicast_vis_packet(struct bat_priv *bat_priv,
  			       struct vis_info *info)
  {
  	struct orig_node *orig_node;

  	struct neigh_node *router = NULL;

  	struct sk_buff *skb;
  	struct vis_packet *packet;

  	packet = (struct vis_packet *)info->skb_packet->data;

  	orig_node = orig_hash_find(bat_priv, packet->target_orig);

  	if (!orig_node)

  		goto out;

  	router = orig_node_get_router(orig_node);
  	if (!router)
  		goto out;

  
  	skb = skb_clone(info->skb_packet, GFP_ATOMIC);
  	if (skb)

  		send_skb_packet(skb, router->if_incoming, router->addr);

  
  out:

  	if (router)
  		neigh_node_free_ref(router);

  	if (orig_node)

  		orig_node_free_ref(orig_node);

  }
  
  /* only send one vis packet. called from send_vis_packets() */
  static void send_vis_packet(struct bat_priv *bat_priv, struct vis_info *info)
  {

  	struct hard_iface *primary_if;

  	struct vis_packet *packet;

  	primary_if = primary_if_get_selected(bat_priv);
  	if (!primary_if)
  		goto out;

  	packet = (struct vis_packet *)info->skb_packet->data;
  	if (packet->ttl < 2) {
  		pr_debug("Error - can't send vis packet: ttl exceeded
  ");

  		goto out;

  	}

  	memcpy(packet->sender_orig, primary_if->net_dev->dev_addr, ETH_ALEN);

  	packet->ttl--;
  
  	if (is_broadcast_ether_addr(packet->target_orig))
  		broadcast_vis_packet(bat_priv, info);
  	else
  		unicast_vis_packet(bat_priv, info);
  	packet->ttl++; /* restore TTL */

  
  out:
  	if (primary_if)
  		hardif_free_ref(primary_if);

  }
  
  /* called from timer; send (and maybe generate) vis packet. */
  static void send_vis_packets(struct work_struct *work)
  {
  	struct delayed_work *delayed_work =
  		container_of(work, struct delayed_work, work);
  	struct bat_priv *bat_priv =
  		container_of(delayed_work, struct bat_priv, vis_work);

  	struct vis_info *info;

  
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  	purge_vis_packets(bat_priv);
  
  	if (generate_vis_packet(bat_priv) == 0) {
  		/* schedule if generation was successful */
  		send_list_add(bat_priv, bat_priv->my_vis_info);
  	}

  	while (!list_empty(&bat_priv->vis_send_list)) {
  		info = list_first_entry(&bat_priv->vis_send_list,
  					typeof(*info), send_list);

  
  		kref_get(&info->refcount);
  		spin_unlock_bh(&bat_priv->vis_hash_lock);

  		send_vis_packet(bat_priv, info);

  
  		spin_lock_bh(&bat_priv->vis_hash_lock);
  		send_list_del(info);
  		kref_put(&info->refcount, free_info);
  	}
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  	start_vis_timer(bat_priv);
  }
  
  /* init the vis server. this may only be called when if_list is already
   * initialized (e.g. bat0 is initialized, interfaces have been added) */
  int vis_init(struct bat_priv *bat_priv)
  {
  	struct vis_packet *packet;
  	int hash_added;
  
  	if (bat_priv->vis_hash)
  		return 1;
  
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  
  	bat_priv->vis_hash = hash_new(256);
  	if (!bat_priv->vis_hash) {
  		pr_err("Can't initialize vis_hash
  ");
  		goto err;
  	}
  
  	bat_priv->my_vis_info = kmalloc(MAX_VIS_PACKET_SIZE, GFP_ATOMIC);

  	if (!bat_priv->my_vis_info)

  		goto err;

  	bat_priv->my_vis_info->skb_packet = dev_alloc_skb(sizeof(*packet) +
  							  MAX_VIS_PACKET_SIZE +
  							 sizeof(struct ethhdr));

  	if (!bat_priv->my_vis_info->skb_packet)
  		goto free_info;
  
  	skb_reserve(bat_priv->my_vis_info->skb_packet, sizeof(struct ethhdr));

  	packet = (struct vis_packet *)skb_put(bat_priv->my_vis_info->skb_packet,
  					      sizeof(*packet));

  
  	/* prefill the vis info */
  	bat_priv->my_vis_info->first_seen = jiffies -
  						msecs_to_jiffies(VIS_INTERVAL);
  	INIT_LIST_HEAD(&bat_priv->my_vis_info->recv_list);
  	INIT_LIST_HEAD(&bat_priv->my_vis_info->send_list);
  	kref_init(&bat_priv->my_vis_info->refcount);
  	bat_priv->my_vis_info->bat_priv = bat_priv;
  	packet->version = COMPAT_VERSION;
  	packet->packet_type = BAT_VIS;
  	packet->ttl = TTL;
  	packet->seqno = 0;
  	packet->entries = 0;
  
  	INIT_LIST_HEAD(&bat_priv->vis_send_list);
  
  	hash_added = hash_add(bat_priv->vis_hash, vis_info_cmp, vis_info_choose,

  			      bat_priv->my_vis_info,
  			      &bat_priv->my_vis_info->hash_entry);

  	if (hash_added != 0) {

  		pr_err("Can't add own vis packet into hash
  ");
  		/* not in hash, need to remove it manually. */
  		kref_put(&bat_priv->my_vis_info->refcount, free_info);
  		goto err;
  	}
  
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  	start_vis_timer(bat_priv);
  	return 1;
  
  free_info:
  	kfree(bat_priv->my_vis_info);
  	bat_priv->my_vis_info = NULL;
  err:
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  	vis_quit(bat_priv);
  	return 0;
  }
  
  /* Decrease the reference count on a hash item info */

  static void free_info_ref(struct hlist_node *node, void *arg)

  {

  	struct vis_info *info;

  	info = container_of(node, struct vis_info, hash_entry);

  	send_list_del(info);
  	kref_put(&info->refcount, free_info);
  }
  
  /* shutdown vis-server */
  void vis_quit(struct bat_priv *bat_priv)
  {
  	if (!bat_priv->vis_hash)
  		return;
  
  	cancel_delayed_work_sync(&bat_priv->vis_work);
  
  	spin_lock_bh(&bat_priv->vis_hash_lock);
  	/* properly remove, kill timers ... */
  	hash_delete(bat_priv->vis_hash, free_info_ref, NULL);
  	bat_priv->vis_hash = NULL;
  	bat_priv->my_vis_info = NULL;
  	spin_unlock_bh(&bat_priv->vis_hash_lock);
  }
  
  /* schedule packets for (re)transmission */
  static void start_vis_timer(struct bat_priv *bat_priv)
  {
  	INIT_DELAYED_WORK(&bat_priv->vis_work, send_vis_packets);
  	queue_delayed_work(bat_event_workqueue, &bat_priv->vis_work,
  			   msecs_to_jiffies(VIS_INTERVAL));
  }