linux/net/batman-adv/routing.c

/*
 * 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 "routing.h"
#include "send.h"
#include "hash.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "translation-table.h"
#include "originator.h"
#include "ring_buffer.h"
#include "vis.h"
#include "aggregation.h"
#include "gateway_common.h"
#include "gateway_client.h"
#include "unicast.h"

void slide_own_bcast_window(struct batman_if *batman_if)
{
	struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);
	struct hashtable_t *hash = bat_priv->orig_hash;
	struct hlist_node *walk;
	struct hlist_head *head;
	struct element_t *bucket;
	struct orig_node *orig_node;
	unsigned long *word;
	int i;
	size_t word_index;

	spin_lock_bh(&bat_priv->orig_hash_lock);

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(bucket, walk, head, hlist) {
			orig_node = bucket->data;
			word_index = batman_if->if_num * NUM_WORDS;
			word = &(orig_node->bcast_own[word_index]);

			bit_get_packet(bat_priv, word, 1, 0);
			orig_node->bcast_own_sum[batman_if->if_num] =
				bit_packet_count(word);
		}
		rcu_read_unlock();
	}

	spin_unlock_bh(&bat_priv->orig_hash_lock);
}

static void update_HNA(struct bat_priv *bat_priv, struct orig_node *orig_node,
		       unsigned char *hna_buff, int hna_buff_len)
{
	if ((hna_buff_len != orig_node->hna_buff_len) ||
	    ((hna_buff_len > 0) &&
	     (orig_node->hna_buff_len > 0) &&
	     (memcmp(orig_node->hna_buff, hna_buff, hna_buff_len) != 0))) {

		if (orig_node->hna_buff_len > 0)
			hna_global_del_orig(bat_priv, orig_node,
					    "originator changed hna");

		if ((hna_buff_len > 0) && (hna_buff))
			hna_global_add_orig(bat_priv, orig_node,
					    hna_buff, hna_buff_len);
	}
}

static void update_route(struct bat_priv *bat_priv,
			 struct orig_node *orig_node,
			 struct neigh_node *neigh_node,
			 unsigned char *hna_buff, int hna_buff_len)
{
	struct neigh_node *neigh_node_tmp;

	/* route deleted */
	if ((orig_node->router) && (!neigh_node)) {

		bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n",
			orig_node->orig);
		hna_global_del_orig(bat_priv, orig_node,
				    "originator timed out");

		/* route added */
	} else if ((!orig_node->router) && (neigh_node)) {

		bat_dbg(DBG_ROUTES, bat_priv,
			"Adding route towards: %pM (via %pM)\n",
			orig_node->orig, neigh_node->addr);
		hna_global_add_orig(bat_priv, orig_node,
				    hna_buff, hna_buff_len);

		/* route changed */
	} else {
		bat_dbg(DBG_ROUTES, bat_priv,
			"Changing route towards: %pM "
			"(now via %pM - was via %pM)\n",
			orig_node->orig, neigh_node->addr,
			orig_node->router->addr);
	}

	if (neigh_node)
		kref_get(&neigh_node->refcount);
	neigh_node_tmp = orig_node->router;
	orig_node->router = neigh_node;
	if (neigh_node_tmp)
		kref_put(&neigh_node_tmp->refcount, neigh_node_free_ref);
}


void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node,
		   struct neigh_node *neigh_node, unsigned char *hna_buff,
		   int hna_buff_len)
{

	if (!orig_node)
		return;

	if (orig_node->router != neigh_node)
		update_route(bat_priv, orig_node, neigh_node,
			     hna_buff, hna_buff_len);
	/* may be just HNA changed */
	else
		update_HNA(bat_priv, orig_node, hna_buff, hna_buff_len);
}

static int is_bidirectional_neigh(struct orig_node *orig_node,
				struct orig_node *orig_neigh_node,
				struct batman_packet *batman_packet,
				struct batman_if *if_incoming)
{
	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
	struct hlist_node *node;
	unsigned char total_count;
	int ret = 0;

	if (orig_node == orig_neigh_node) {
		rcu_read_lock();
		hlist_for_each_entry_rcu(tmp_neigh_node, node,
					 &orig_node->neigh_list, list) {

			if (compare_orig(tmp_neigh_node->addr,
					 orig_neigh_node->orig) &&
			    (tmp_neigh_node->if_incoming == if_incoming))
				neigh_node = tmp_neigh_node;
		}

		if (!neigh_node)
			neigh_node = create_neighbor(orig_node,
						     orig_neigh_node,
						     orig_neigh_node->orig,
						     if_incoming);
		/* create_neighbor failed, return 0 */
		if (!neigh_node)
			goto unlock;

		kref_get(&neigh_node->refcount);
		rcu_read_unlock();

		neigh_node->last_valid = jiffies;
	} else {
		/* find packet count of corresponding one hop neighbor */
		rcu_read_lock();
		hlist_for_each_entry_rcu(tmp_neigh_node, node,
					 &orig_neigh_node->neigh_list, list) {

			if (compare_orig(tmp_neigh_node->addr,
					 orig_neigh_node->orig) &&
			    (tmp_neigh_node->if_incoming == if_incoming))
				neigh_node = tmp_neigh_node;
		}

		if (!neigh_node)
			neigh_node = create_neighbor(orig_neigh_node,
						     orig_neigh_node,
						     orig_neigh_node->orig,
						     if_incoming);
		/* create_neighbor failed, return 0 */
		if (!neigh_node)
			goto unlock;

		kref_get(&neigh_node->refcount);
		rcu_read_unlock();
	}

	orig_node->last_valid = jiffies;

	/* pay attention to not get a value bigger than 100 % */
	total_count = (orig_neigh_node->bcast_own_sum[if_incoming->if_num] >
		       neigh_node->real_packet_count ?
		       neigh_node->real_packet_count :
		       orig_neigh_node->bcast_own_sum[if_incoming->if_num]);

	/* if we have too few packets (too less data) we set tq_own to zero */
	/* if we receive too few packets it is not considered bidirectional */
	if ((total_count < TQ_LOCAL_BIDRECT_SEND_MINIMUM) ||
	    (neigh_node->real_packet_count < TQ_LOCAL_BIDRECT_RECV_MINIMUM))
		orig_neigh_node->tq_own = 0;
	else
		/* neigh_node->real_packet_count is never zero as we
		 * only purge old information when getting new
		 * information */
		orig_neigh_node->tq_own = (TQ_MAX_VALUE * total_count) /
			neigh_node->real_packet_count;

	/*
	 * 1 - ((1-x) ** 3), normalized to TQ_MAX_VALUE this does
	 * affect the nearly-symmetric links only a little, but
	 * punishes asymmetric links more.  This will give a value
	 * between 0 and TQ_MAX_VALUE
	 */
	orig_neigh_node->tq_asym_penalty =
		TQ_MAX_VALUE -
		(TQ_MAX_VALUE *
		 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count) *
		 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count) *
		 (TQ_LOCAL_WINDOW_SIZE - neigh_node->real_packet_count)) /
		(TQ_LOCAL_WINDOW_SIZE *
		 TQ_LOCAL_WINDOW_SIZE *
		 TQ_LOCAL_WINDOW_SIZE);

	batman_packet->tq = ((batman_packet->tq *
			      orig_neigh_node->tq_own *
			      orig_neigh_node->tq_asym_penalty) /
			     (TQ_MAX_VALUE * TQ_MAX_VALUE));

	bat_dbg(DBG_BATMAN, bat_priv,
		"bidirectional: "
		"orig = %-15pM neigh = %-15pM => own_bcast = %2i, "
		"real recv = %2i, local tq: %3i, asym_penalty: %3i, "
		"total tq: %3i\n",
		orig_node->orig, orig_neigh_node->orig, total_count,
		neigh_node->real_packet_count, orig_neigh_node->tq_own,
		orig_neigh_node->tq_asym_penalty, batman_packet->tq);

	/* if link has the minimum required transmission quality
	 * consider it bidirectional */
	if (batman_packet->tq >= TQ_TOTAL_BIDRECT_LIMIT)
		ret = 1;

	goto out;

unlock:
	rcu_read_unlock();
out:
	if (neigh_node)
		kref_put(&neigh_node->refcount, neigh_node_free_ref);
	return ret;
}

static void update_orig(struct bat_priv *bat_priv,
			struct orig_node *orig_node,
			struct ethhdr *ethhdr,
			struct batman_packet *batman_packet,
			struct batman_if *if_incoming,
			unsigned char *hna_buff, int hna_buff_len,
			char is_duplicate)
{
	struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
	struct hlist_node *node;
	int tmp_hna_buff_len;

	bat_dbg(DBG_BATMAN, bat_priv, "update_originator(): "
		"Searching and updating originator entry of received packet\n");

	rcu_read_lock();
	hlist_for_each_entry_rcu(tmp_neigh_node, node,
				 &orig_node->neigh_list, list) {
		if (compare_orig(tmp_neigh_node->addr, ethhdr->h_source) &&
		    (tmp_neigh_node->if_incoming == if_incoming)) {
			neigh_node = tmp_neigh_node;
			continue;
		}

		if (is_duplicate)
			continue;

		ring_buffer_set(tmp_neigh_node->tq_recv,
				&tmp_neigh_node->tq_index, 0);
		tmp_neigh_node->tq_avg =
			ring_buffer_avg(tmp_neigh_node->tq_recv);
	}

	if (!neigh_node) {
		struct orig_node *orig_tmp;

		orig_tmp = get_orig_node(bat_priv, ethhdr->h_source);
		if (!orig_tmp)
			goto unlock;

		neigh_node = create_neighbor(orig_node, orig_tmp,
					     ethhdr->h_source, if_incoming);

		kref_put(&orig_tmp->refcount, orig_node_free_ref);
		if (!neigh_node)
			goto unlock;
	} else
		bat_dbg(DBG_BATMAN, bat_priv,
			"Updating existing last-hop neighbor of originator\n");

	kref_get(&neigh_node->refcount);
	rcu_read_unlock();

	orig_node->flags = batman_packet->flags;
	neigh_node->last_valid = jiffies;

	ring_buffer_set(neigh_node->tq_recv,
			&neigh_node->tq_index,
			batman_packet->tq);
	neigh_node->tq_avg = ring_buffer_avg(neigh_node->tq_recv);

	if (!is_duplicate) {
		orig_node->last_ttl = batman_packet->ttl;
		neigh_node->last_ttl = batman_packet->ttl;
	}

	tmp_hna_buff_len = (hna_buff_len > batman_packet->num_hna * ETH_ALEN ?
			    batman_packet->num_hna * ETH_ALEN : hna_buff_len);

	/* if this neighbor already is our next hop there is nothing
	 * to change */
	if (orig_node->router == neigh_node)
		goto update_hna;

	/* if this neighbor does not offer a better TQ we won't consider it */
	if ((orig_node->router) &&
	    (orig_node->router->tq_avg > neigh_node->tq_avg))
		goto update_hna;

	/* if the TQ is the same and the link not more symetric we
	 * won't consider it either */
	if ((orig_node->router) &&
	     ((neigh_node->tq_avg == orig_node->router->tq_avg) &&
	     (orig_node->router->orig_node->bcast_own_sum[if_incoming->if_num]
	      >= neigh_node->orig_node->bcast_own_sum[if_incoming->if_num])))
		goto update_hna;

	update_routes(bat_priv, orig_node, neigh_node,
		      hna_buff, tmp_hna_buff_len);
	goto update_gw;

update_hna:
	update_routes(bat_priv, orig_node, orig_node->router,
		      hna_buff, tmp_hna_buff_len);

update_gw:
	if (orig_node->gw_flags != batman_packet->gw_flags)
		gw_node_update(bat_priv, orig_node, batman_packet->gw_flags);

	orig_node->gw_flags = batman_packet->gw_flags;

	/* restart gateway selection if fast or late switching was enabled */
	if ((orig_node->gw_flags) &&
	    (atomic_read(&bat_priv->gw_mode) == GW_MODE_CLIENT) &&
	    (atomic_read(&bat_priv->gw_sel_class) > 2))
		gw_check_election(bat_priv, orig_node);

	goto out;

unlock:
	rcu_read_unlock();
out:
	if (neigh_node)
		kref_put(&neigh_node->refcount, neigh_node_free_ref);
}

/* checks whether the host restarted and is in the protection time.
 * returns:
 *  0 if the packet is to be accepted
 *  1 if the packet is to be ignored.
 */
static int window_protected(struct bat_priv *bat_priv,
			    int32_t seq_num_diff,
			    unsigned long *last_reset)
{
	if ((seq_num_diff <= -TQ_LOCAL_WINDOW_SIZE)
		|| (seq_num_diff >= EXPECTED_SEQNO_RANGE)) {
		if (time_after(jiffies, *last_reset +
			msecs_to_jiffies(RESET_PROTECTION_MS))) {

			*last_reset = jiffies;
			bat_dbg(DBG_BATMAN, bat_priv,
				"old packet received, start protection\n");

			return 0;
		} else
			return 1;
	}
	return 0;
}

/* processes a batman packet for all interfaces, adjusts the sequence number and
 * finds out whether it is a duplicate.
 * returns:
 *   1 the packet is a duplicate
 *   0 the packet has not yet been received
 *  -1 the packet is old and has been received while the seqno window
 *     was protected. Caller should drop it.
 */
static char count_real_packets(struct ethhdr *ethhdr,
			       struct batman_packet *batman_packet,
			       struct batman_if *if_incoming)
{
	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct orig_node *orig_node;
	struct neigh_node *tmp_neigh_node;
	struct hlist_node *node;
	char is_duplicate = 0;
	int32_t seq_diff;
	int need_update = 0;
	int set_mark;

	orig_node = get_orig_node(bat_priv, batman_packet->orig);
	if (!orig_node)
		return 0;

	seq_diff = batman_packet->seqno - orig_node->last_real_seqno;

	/* signalize caller that the packet is to be dropped. */
	if (window_protected(bat_priv, seq_diff,
			     &orig_node->batman_seqno_reset))
		goto err;

	rcu_read_lock();
	hlist_for_each_entry_rcu(tmp_neigh_node, node,
				 &orig_node->neigh_list, list) {

		is_duplicate |= get_bit_status(tmp_neigh_node->real_bits,
					       orig_node->last_real_seqno,
					       batman_packet->seqno);

		if (compare_orig(tmp_neigh_node->addr, ethhdr->h_source) &&
		    (tmp_neigh_node->if_incoming == if_incoming))
			set_mark = 1;
		else
			set_mark = 0;

		/* if the window moved, set the update flag. */
		need_update |= bit_get_packet(bat_priv,
					      tmp_neigh_node->real_bits,
					      seq_diff, set_mark);

		tmp_neigh_node->real_packet_count =
			bit_packet_count(tmp_neigh_node->real_bits);
	}
	rcu_read_unlock();

	if (need_update) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"updating last_seqno: old %d, new %d\n",
			orig_node->last_real_seqno, batman_packet->seqno);
		orig_node->last_real_seqno = batman_packet->seqno;
	}

	kref_put(&orig_node->refcount, orig_node_free_ref);
	return is_duplicate;

err:
	kref_put(&orig_node->refcount, orig_node_free_ref);
	return -1;
}

/* copy primary address for bonding */
static void mark_bonding_address(struct orig_node *orig_node,
				 struct orig_node *orig_neigh_node,
				 struct batman_packet *batman_packet)

{
	if (batman_packet->flags & PRIMARIES_FIRST_HOP)
		memcpy(orig_neigh_node->primary_addr,
		       orig_node->orig, ETH_ALEN);

	return;
}

/* mark possible bond.candidates in the neighbor list */
void update_bonding_candidates(struct orig_node *orig_node)
{
	int candidates;
	int interference_candidate;
	int best_tq;
	struct hlist_node *node, *node2;
	struct neigh_node *tmp_neigh_node, *tmp_neigh_node2;
	struct neigh_node *first_candidate, *last_candidate;

	/* update the candidates for this originator */
	if (!orig_node->router) {
		orig_node->bond.candidates = 0;
		return;
	}

	best_tq = orig_node->router->tq_avg;

	/* update bond.candidates */

	candidates = 0;

	/* mark other nodes which also received "PRIMARIES FIRST HOP" packets
	 * as "bonding partner" */

	/* first, zero the list */
	rcu_read_lock();
	hlist_for_each_entry_rcu(tmp_neigh_node, node,
				 &orig_node->neigh_list, list) {
		tmp_neigh_node->next_bond_candidate = NULL;
	}
	rcu_read_unlock();

	first_candidate = NULL;
	last_candidate = NULL;

	rcu_read_lock();
	hlist_for_each_entry_rcu(tmp_neigh_node, node,
				 &orig_node->neigh_list, list) {

		/* only consider if it has the same primary address ...  */
		if (memcmp(orig_node->orig,
				tmp_neigh_node->orig_node->primary_addr,
				ETH_ALEN) != 0)
			continue;

		/* ... and is good enough to be considered */
		if (tmp_neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD)
			continue;

		/* check if we have another candidate with the same
		 * mac address or interface. If we do, we won't
		 * select this candidate because of possible interference. */

		interference_candidate = 0;
		hlist_for_each_entry_rcu(tmp_neigh_node2, node2,
					 &orig_node->neigh_list, list) {

			if (tmp_neigh_node2 == tmp_neigh_node)
				continue;

			/* we only care if the other candidate is even
			 * considered as candidate. */
			if (!tmp_neigh_node2->next_bond_candidate)
				continue;


			if ((tmp_neigh_node->if_incoming ==
				tmp_neigh_node2->if_incoming)
				|| (memcmp(tmp_neigh_node->addr,
				tmp_neigh_node2->addr, ETH_ALEN) == 0)) {

				interference_candidate = 1;
				break;
			}
		}
		/* don't care further if it is an interference candidate */
		if (interference_candidate)
			continue;

		if (!first_candidate) {
			first_candidate = tmp_neigh_node;
			tmp_neigh_node->next_bond_candidate = first_candidate;
		} else
			tmp_neigh_node->next_bond_candidate = last_candidate;

		last_candidate = tmp_neigh_node;

		candidates++;
	}
	rcu_read_unlock();

	if (candidates > 0) {
		first_candidate->next_bond_candidate = last_candidate;
		orig_node->bond.selected = first_candidate;
	}

	orig_node->bond.candidates = candidates;
}

void receive_bat_packet(struct ethhdr *ethhdr,
				struct batman_packet *batman_packet,
				unsigned char *hna_buff, int hna_buff_len,
				struct batman_if *if_incoming)
{
	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct batman_if *batman_if;
	struct orig_node *orig_neigh_node, *orig_node;
	char has_directlink_flag;
	char is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
	char is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
	char is_duplicate;
	uint32_t if_incoming_seqno;

	/* Silently drop when the batman packet is actually not a
	 * correct packet.
	 *
	 * This might happen if a packet is padded (e.g. Ethernet has a
	 * minimum frame length of 64 byte) and the aggregation interprets
	 * it as an additional length.
	 *
	 * TODO: A more sane solution would be to have a bit in the
	 * batman_packet to detect whether the packet is the last
	 * packet in an aggregation.  Here we expect that the padding
	 * is always zero (or not 0x01)
	 */
	if (batman_packet->packet_type != BAT_PACKET)
		return;

	/* could be changed by schedule_own_packet() */
	if_incoming_seqno = atomic_read(&if_incoming->seqno);

	has_directlink_flag = (batman_packet->flags & DIRECTLINK ? 1 : 0);

	is_single_hop_neigh = (compare_orig(ethhdr->h_source,
					    batman_packet->orig) ? 1 : 0);

	bat_dbg(DBG_BATMAN, bat_priv,
		"Received BATMAN packet via NB: %pM, IF: %s [%pM] "
		"(from OG: %pM, via prev OG: %pM, seqno %d, tq %d, "
		"TTL %d, V %d, IDF %d)\n",
		ethhdr->h_source, if_incoming->net_dev->name,
		if_incoming->net_dev->dev_addr, batman_packet->orig,
		batman_packet->prev_sender, batman_packet->seqno,
		batman_packet->tq, batman_packet->ttl, batman_packet->version,
		has_directlink_flag);

	rcu_read_lock();
	list_for_each_entry_rcu(batman_if, &if_list, list) {
		if (batman_if->if_status != IF_ACTIVE)
			continue;

		if (batman_if->soft_iface != if_incoming->soft_iface)
			continue;

		if (compare_orig(ethhdr->h_source,
				 batman_if->net_dev->dev_addr))
			is_my_addr = 1;

		if (compare_orig(batman_packet->orig,
				 batman_if->net_dev->dev_addr))
			is_my_orig = 1;

		if (compare_orig(batman_packet->prev_sender,
				 batman_if->net_dev->dev_addr))
			is_my_oldorig = 1;

		if (compare_orig(ethhdr->h_source, broadcast_addr))
			is_broadcast = 1;
	}
	rcu_read_unlock();

	if (batman_packet->version != COMPAT_VERSION) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: incompatible batman version (%i)\n",
			batman_packet->version);
		return;
	}

	if (is_my_addr) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: received my own broadcast (sender: %pM"
			")\n",
			ethhdr->h_source);
		return;
	}

	if (is_broadcast) {
		bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: "
		"ignoring all packets with broadcast source addr (sender: %pM"
		")\n", ethhdr->h_source);
		return;
	}

	if (is_my_orig) {
		unsigned long *word;
		int offset;

		orig_neigh_node = get_orig_node(bat_priv, ethhdr->h_source);
		if (!orig_neigh_node)
			return;

		/* neighbor has to indicate direct link and it has to
		 * come via the corresponding interface */
		/* if received seqno equals last send seqno save new
		 * seqno for bidirectional check */
		if (has_directlink_flag &&
		    compare_orig(if_incoming->net_dev->dev_addr,
				 batman_packet->orig) &&
		    (batman_packet->seqno - if_incoming_seqno + 2 == 0)) {
			offset = if_incoming->if_num * NUM_WORDS;
			word = &(orig_neigh_node->bcast_own[offset]);
			bit_mark(word, 0);
			orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
				bit_packet_count(word);
		}

		bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: "
			"originator packet from myself (via neighbor)\n");
		kref_put(&orig_neigh_node->refcount, orig_node_free_ref);
		return;
	}

	if (is_my_oldorig) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: ignoring all rebroadcast echos (sender: "
			"%pM)\n", ethhdr->h_source);
		return;
	}

	orig_node = get_orig_node(bat_priv, batman_packet->orig);
	if (!orig_node)
		return;

	is_duplicate = count_real_packets(ethhdr, batman_packet, if_incoming);

	if (is_duplicate == -1) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: packet within seqno protection time "
			"(sender: %pM)\n", ethhdr->h_source);
		goto out;
	}

	if (batman_packet->tq == 0) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: originator packet with tq equal 0\n");
		goto out;
	}

	/* avoid temporary routing loops */
	if ((orig_node->router) &&
	    (orig_node->router->orig_node->router) &&
	    (compare_orig(orig_node->router->addr,
			  batman_packet->prev_sender)) &&
	    !(compare_orig(batman_packet->orig, batman_packet->prev_sender)) &&
	    (compare_orig(orig_node->router->addr,
			  orig_node->router->orig_node->router->addr))) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: ignoring all rebroadcast packets that "
			"may make me loop (sender: %pM)\n", ethhdr->h_source);
		goto out;
	}

	/* if sender is a direct neighbor the sender mac equals
	 * originator mac */
	orig_neigh_node = (is_single_hop_neigh ?
			   orig_node :
			   get_orig_node(bat_priv, ethhdr->h_source));
	if (!orig_neigh_node)
		goto out_neigh;

	/* drop packet if sender is not a direct neighbor and if we
	 * don't route towards it */
	if (!is_single_hop_neigh && (!orig_neigh_node->router)) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: OGM via unknown neighbor!\n");
		goto out_neigh;
	}

	is_bidirectional = is_bidirectional_neigh(orig_node, orig_neigh_node,
						batman_packet, if_incoming);

	/* update ranking if it is not a duplicate or has the same
	 * seqno and similar ttl as the non-duplicate */
	if (is_bidirectional &&
	    (!is_duplicate ||
	     ((orig_node->last_real_seqno == batman_packet->seqno) &&
	      (orig_node->last_ttl - 3 <= batman_packet->ttl))))
		update_orig(bat_priv, orig_node, ethhdr, batman_packet,
			    if_incoming, hna_buff, hna_buff_len, is_duplicate);

	mark_bonding_address(orig_node, orig_neigh_node, batman_packet);
	update_bonding_candidates(orig_node);

	/* is single hop (direct) neighbor */
	if (is_single_hop_neigh) {

		/* mark direct link on incoming interface */
		schedule_forward_packet(orig_node, ethhdr, batman_packet,
					1, hna_buff_len, if_incoming);

		bat_dbg(DBG_BATMAN, bat_priv, "Forwarding packet: "
			"rebroadcast neighbor packet with direct link flag\n");
		goto out_neigh;
	}

	/* multihop originator */
	if (!is_bidirectional) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: not received via bidirectional link\n");
		goto out_neigh;
	}

	if (is_duplicate) {
		bat_dbg(DBG_BATMAN, bat_priv,
			"Drop packet: duplicate packet received\n");
		goto out_neigh;
	}

	bat_dbg(DBG_BATMAN, bat_priv,
		"Forwarding packet: rebroadcast originator packet\n");
	schedule_forward_packet(orig_node, ethhdr, batman_packet,
				0, hna_buff_len, if_incoming);

out_neigh:
	if (!is_single_hop_neigh)
		kref_put(&orig_neigh_node->refcount, orig_node_free_ref);
out:
	kref_put(&orig_node->refcount, orig_node_free_ref);
}

int recv_bat_packet(struct sk_buff *skb, struct batman_if *batman_if)
{
	struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);
	struct ethhdr *ethhdr;

	/* drop packet if it has not necessary minimum size */
	if (unlikely(!pskb_may_pull(skb, sizeof(struct batman_packet))))
		return NET_RX_DROP;

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

	/* packet with broadcast indication but unicast recipient */
	if (!is_broadcast_ether_addr(ethhdr->h_dest))
		return NET_RX_DROP;

	/* packet with broadcast sender address */
	if (is_broadcast_ether_addr(ethhdr->h_source))
		return NET_RX_DROP;

	/* create a copy of the skb, if needed, to modify it. */
	if (skb_cow(skb, 0) < 0)
		return NET_RX_DROP;

	/* keep skb linear */
	if (skb_linearize(skb) < 0)
		return NET_RX_DROP;

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

	spin_lock_bh(&bat_priv->orig_hash_lock);
	receive_aggr_bat_packet(ethhdr,
				skb->data,
				skb_headlen(skb),
				batman_if);
	spin_unlock_bh(&bat_priv->orig_hash_lock);

	kfree_skb(skb);
	return NET_RX_SUCCESS;
}

static int recv_my_icmp_packet(struct bat_priv *bat_priv,
			       struct sk_buff *skb, size_t icmp_len)
{
	struct orig_node *orig_node;
	struct icmp_packet_rr *icmp_packet;
	struct batman_if *batman_if;
	int ret;
	uint8_t dstaddr[ETH_ALEN];

	icmp_packet = (struct icmp_packet_rr *)skb->data;

	/* add data to device queue */
	if (icmp_packet->msg_type != ECHO_REQUEST) {
		bat_socket_receive_packet(icmp_packet, icmp_len);
		return NET_RX_DROP;
	}

	if (!bat_priv->primary_if)
		return NET_RX_DROP;

	/* answer echo request (ping) */
	/* get routing information */
	spin_lock_bh(&bat_priv->orig_hash_lock);
	rcu_read_lock();
	orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
						   compare_orig, choose_orig,
						   icmp_packet->orig));
	rcu_read_unlock();
	ret = NET_RX_DROP;

	if ((orig_node) && (orig_node->router)) {

		/* don't lock while sending the packets ... we therefore
		 * copy the required data before sending */
		batman_if = orig_node->router->if_incoming;
		memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
		spin_unlock_bh(&bat_priv->orig_hash_lock);

		/* create a copy of the skb, if needed, to modify it. */
		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
			return NET_RX_DROP;

		icmp_packet = (struct icmp_packet_rr *)skb->data;

		memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
		memcpy(icmp_packet->orig,
		       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
		icmp_packet->msg_type = ECHO_REPLY;
		icmp_packet->ttl = TTL;

		send_skb_packet(skb, batman_if, dstaddr);
		ret = NET_RX_SUCCESS;

	} else
		spin_unlock_bh(&bat_priv->orig_hash_lock);

	return ret;
}

static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv,
				  struct sk_buff *skb)
{
	struct orig_node *orig_node;
	struct icmp_packet *icmp_packet;
	struct batman_if *batman_if;
	int ret;
	uint8_t dstaddr[ETH_ALEN];

	icmp_packet = (struct icmp_packet *)skb->data;

	/* send TTL exceeded if packet is an echo request (traceroute) */
	if (icmp_packet->msg_type != ECHO_REQUEST) {
		pr_debug("Warning - can't forward icmp packet from %pM to "
			 "%pM: ttl exceeded\n", icmp_packet->orig,
			 icmp_packet->dst);
		return NET_RX_DROP;
	}

	if (!bat_priv->primary_if)
		return NET_RX_DROP;

	/* get routing information */
	spin_lock_bh(&bat_priv->orig_hash_lock);
	rcu_read_lock();
	orig_node = ((struct orig_node *)
		     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
			       icmp_packet->orig));
	rcu_read_unlock();
	ret = NET_RX_DROP;

	if ((orig_node) && (orig_node->router)) {

		/* don't lock while sending the packets ... we therefore
		 * copy the required data before sending */
		batman_if = orig_node->router->if_incoming;
		memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
		spin_unlock_bh(&bat_priv->orig_hash_lock);

		/* create a copy of the skb, if needed, to modify it. */
		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
			return NET_RX_DROP;

		icmp_packet = (struct icmp_packet *) skb->data;

		memcpy(icmp_packet->dst, icmp_packet->orig, ETH_ALEN);
		memcpy(icmp_packet->orig,
		       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
		icmp_packet->msg_type = TTL_EXCEEDED;
		icmp_packet->ttl = TTL;

		send_skb_packet(skb, batman_if, dstaddr);
		ret = NET_RX_SUCCESS;

	} else
		spin_unlock_bh(&bat_priv->orig_hash_lock);

	return ret;
}


int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	struct icmp_packet_rr *icmp_packet;
	struct ethhdr *ethhdr;
	struct orig_node *orig_node;
	struct batman_if *batman_if;
	int hdr_size = sizeof(struct icmp_packet);
	int ret;
	uint8_t dstaddr[ETH_ALEN];

	/**
	 * we truncate all incoming icmp packets if they don't match our size
	 */
	if (skb->len >= sizeof(struct icmp_packet_rr))
		hdr_size = sizeof(struct icmp_packet_rr);

	/* drop packet if it has not necessary minimum size */
	if (unlikely(!pskb_may_pull(skb, hdr_size)))
		return NET_RX_DROP;

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

	/* packet with unicast indication but broadcast recipient */
	if (is_broadcast_ether_addr(ethhdr->h_dest))
		return NET_RX_DROP;

	/* packet with broadcast sender address */
	if (is_broadcast_ether_addr(ethhdr->h_source))
		return NET_RX_DROP;

	/* not for me */
	if (!is_my_mac(ethhdr->h_dest))
		return NET_RX_DROP;

	icmp_packet = (struct icmp_packet_rr *)skb->data;

	/* add record route information if not full */
	if ((hdr_size == sizeof(struct icmp_packet_rr)) &&
	    (icmp_packet->rr_cur < BAT_RR_LEN)) {
		memcpy(&(icmp_packet->rr[icmp_packet->rr_cur]),
			ethhdr->h_dest, ETH_ALEN);
		icmp_packet->rr_cur++;
	}

	/* packet for me */
	if (is_my_mac(icmp_packet->dst))
		return recv_my_icmp_packet(bat_priv, skb, hdr_size);

	/* TTL exceeded */
	if (icmp_packet->ttl < 2)
		return recv_icmp_ttl_exceeded(bat_priv, skb);

	ret = NET_RX_DROP;

	/* get routing information */
	spin_lock_bh(&bat_priv->orig_hash_lock);
	rcu_read_lock();
	orig_node = ((struct orig_node *)
		     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
			       icmp_packet->dst));
	rcu_read_unlock();

	if ((orig_node) && (orig_node->router)) {

		/* don't lock while sending the packets ... we therefore
		 * copy the required data before sending */
		batman_if = orig_node->router->if_incoming;
		memcpy(dstaddr, orig_node->router->addr, ETH_ALEN);
		spin_unlock_bh(&bat_priv->orig_hash_lock);

		/* create a copy of the skb, if needed, to modify it. */
		if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
			return NET_RX_DROP;

		icmp_packet = (struct icmp_packet_rr *)skb->data;

		/* decrement ttl */
		icmp_packet->ttl--;

		/* route it */
		send_skb_packet(skb, batman_if, dstaddr);
		ret = NET_RX_SUCCESS;

	} else
		spin_unlock_bh(&bat_priv->orig_hash_lock);

	return ret;
}

/* find a suitable router for this originator, and use
 * bonding if possible. */
struct neigh_node *find_router(struct bat_priv *bat_priv,
			       struct orig_node *orig_node,
			       struct batman_if *recv_if)
{
	struct orig_node *primary_orig_node;
	struct orig_node *router_orig;
	struct neigh_node *router, *first_candidate, *best_router;
	static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0};
	int bonding_enabled;

	if (!orig_node)
		return NULL;

	if (!orig_node->router)
		return NULL;

	/* without bonding, the first node should
	 * always choose the default router. */

	bonding_enabled = atomic_read(&bat_priv->bonding);

	if ((!recv_if) && (!bonding_enabled))
		return orig_node->router;

	router_orig = orig_node->router->orig_node;

	/* if we have something in the primary_addr, we can search
	 * for a potential bonding candidate. */
	if (memcmp(router_orig->primary_addr, zero_mac, ETH_ALEN) == 0)
		return orig_node->router;

	/* find the orig_node which has the primary interface. might
	 * even be the same as our router_orig in many cases */

	if (memcmp(router_orig->primary_addr,
				router_orig->orig, ETH_ALEN) == 0) {
		primary_orig_node = router_orig;
	} else {
		rcu_read_lock();
		primary_orig_node = hash_find(bat_priv->orig_hash, compare_orig,
					       choose_orig,
					       router_orig->primary_addr);
		rcu_read_unlock();

		if (!primary_orig_node)
			return orig_node->router;
	}

	/* with less than 2 candidates, we can't do any
	 * bonding and prefer the original router. */

	if (primary_orig_node->bond.candidates < 2)
		return orig_node->router;


	/* all nodes between should choose a candidate which
	 * is is not on the interface where the packet came
	 * in. */
	first_candidate = primary_orig_node->bond.selected;
	router = first_candidate;

	if (bonding_enabled) {
		/* in the bonding case, send the packets in a round
		 * robin fashion over the remaining interfaces. */
		do {
			/* recv_if == NULL on the first node. */
			if (router->if_incoming != recv_if)
				break;

			router = router->next_bond_candidate;
		} while (router != first_candidate);

		primary_orig_node->bond.selected = router->next_bond_candidate;

	} else {
		/* if bonding is disabled, use the best of the
		 * remaining candidates which are not using
		 * this interface. */
		best_router = first_candidate;

		do {
			/* recv_if == NULL on the first node. */
			if ((router->if_incoming != recv_if) &&
				(router->tq_avg > best_router->tq_avg))
					best_router = router;

			router = router->next_bond_candidate;
		} while (router != first_candidate);

		router = best_router;
	}

	return router;
}

static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
{
	struct ethhdr *ethhdr;

	/* drop packet if it has not necessary minimum size */
	if (unlikely(!pskb_may_pull(skb, hdr_size)))
		return -1;

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

	/* packet with unicast indication but broadcast recipient */
	if (is_broadcast_ether_addr(ethhdr->h_dest))
		return -1;

	/* packet with broadcast sender address */
	if (is_broadcast_ether_addr(ethhdr->h_source))
		return -1;

	/* not for me */
	if (!is_my_mac(ethhdr->h_dest))
		return -1;

	return 0;
}

int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if,
			 int hdr_size)
{
	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	struct orig_node *orig_node;
	struct neigh_node *router;
	struct batman_if *batman_if;
	uint8_t dstaddr[ETH_ALEN];
	struct unicast_packet *unicast_packet;
	struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
	int ret;
	struct sk_buff *new_skb;

	unicast_packet = (struct unicast_packet *)skb->data;

	/* TTL exceeded */
	if (unicast_packet->ttl < 2) {
		pr_debug("Warning - can't forward unicast packet from %pM to "
			 "%pM: ttl exceeded\n", ethhdr->h_source,
			 unicast_packet->dest);
		return NET_RX_DROP;
	}

	/* get routing information */
	spin_lock_bh(&bat_priv->orig_hash_lock);
	rcu_read_lock();
	orig_node = ((struct orig_node *)
		     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
			       unicast_packet->dest));
	rcu_read_unlock();

	router = find_router(bat_priv, orig_node, recv_if);

	if (!router) {
		spin_unlock_bh(&bat_priv->orig_hash_lock);
		return NET_RX_DROP;
	}

	/* don't lock while sending the packets ... we therefore
	 * copy the required data before sending */

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

	spin_unlock_bh(&bat_priv->orig_hash_lock);

	/* create a copy of the skb, if needed, to modify it. */
	if (skb_cow(skb, sizeof(struct ethhdr)) < 0)
		return NET_RX_DROP;

	unicast_packet = (struct unicast_packet *)skb->data;

	if (unicast_packet->packet_type == BAT_UNICAST &&
	    atomic_read(&bat_priv->fragmentation) &&
	    skb->len > batman_if->net_dev->mtu)
		return frag_send_skb(skb, bat_priv, batman_if,
				     dstaddr);

	if (unicast_packet->packet_type == BAT_UNICAST_FRAG &&
	    frag_can_reassemble(skb, batman_if->net_dev->mtu)) {

		ret = frag_reassemble_skb(skb, bat_priv, &new_skb);

		if (ret == NET_RX_DROP)
			return NET_RX_DROP;

		/* packet was buffered for late merge */
		if (!new_skb)
			return NET_RX_SUCCESS;

		skb = new_skb;
		unicast_packet = (struct unicast_packet *)skb->data;
	}

	/* decrement ttl */
	unicast_packet->ttl--;

	/* route it */
	send_skb_packet(skb, batman_if, dstaddr);

	return NET_RX_SUCCESS;
}

int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
	struct unicast_packet *unicast_packet;
	int hdr_size = sizeof(struct unicast_packet);

	if (check_unicast_packet(skb, hdr_size) < 0)
		return NET_RX_DROP;

	unicast_packet = (struct unicast_packet *)skb->data;

	/* packet for me */
	if (is_my_mac(unicast_packet->dest)) {
		interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);
		return NET_RX_SUCCESS;
	}

	return route_unicast_packet(skb, recv_if, hdr_size);
}

int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	struct unicast_frag_packet *unicast_packet;
	int hdr_size = sizeof(struct unicast_frag_packet);
	struct sk_buff *new_skb = NULL;
	int ret;

	if (check_unicast_packet(skb, hdr_size) < 0)
		return NET_RX_DROP;

	unicast_packet = (struct unicast_frag_packet *)skb->data;

	/* packet for me */
	if (is_my_mac(unicast_packet->dest)) {

		ret = frag_reassemble_skb(skb, bat_priv, &new_skb);

		if (ret == NET_RX_DROP)
			return NET_RX_DROP;

		/* packet was buffered for late merge */
		if (!new_skb)
			return NET_RX_SUCCESS;

		interface_rx(recv_if->soft_iface, new_skb, recv_if,
			     sizeof(struct unicast_packet));
		return NET_RX_SUCCESS;
	}

	return route_unicast_packet(skb, recv_if, hdr_size);
}


int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	struct orig_node *orig_node;
	struct bcast_packet *bcast_packet;
	struct ethhdr *ethhdr;
	int hdr_size = sizeof(struct bcast_packet);
	int32_t seq_diff;

	/* drop packet if it has not necessary minimum size */
	if (unlikely(!pskb_may_pull(skb, hdr_size)))
		return NET_RX_DROP;

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

	/* packet with broadcast indication but unicast recipient */
	if (!is_broadcast_ether_addr(ethhdr->h_dest))
		return NET_RX_DROP;

	/* packet with broadcast sender address */
	if (is_broadcast_ether_addr(ethhdr->h_source))
		return NET_RX_DROP;

	/* ignore broadcasts sent by myself */
	if (is_my_mac(ethhdr->h_source))
		return NET_RX_DROP;

	bcast_packet = (struct bcast_packet *)skb->data;

	/* ignore broadcasts originated by myself */
	if (is_my_mac(bcast_packet->orig))
		return NET_RX_DROP;

	if (bcast_packet->ttl < 2)
		return NET_RX_DROP;

	spin_lock_bh(&bat_priv->orig_hash_lock);
	rcu_read_lock();
	orig_node = ((struct orig_node *)
		     hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
			       bcast_packet->orig));
	rcu_read_unlock();

	if (!orig_node) {
		spin_unlock_bh(&bat_priv->orig_hash_lock);
		return NET_RX_DROP;
	}

	/* check whether the packet is a duplicate */
	if (get_bit_status(orig_node->bcast_bits,
			   orig_node->last_bcast_seqno,
			   ntohl(bcast_packet->seqno))) {
		spin_unlock_bh(&bat_priv->orig_hash_lock);
		return NET_RX_DROP;
	}

	seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;

	/* check whether the packet is old and the host just restarted. */
	if (window_protected(bat_priv, seq_diff,
			     &orig_node->bcast_seqno_reset)) {
		spin_unlock_bh(&bat_priv->orig_hash_lock);
		return NET_RX_DROP;
	}

	/* mark broadcast in flood history, update window position
	 * if required. */
	if (bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
		orig_node->last_bcast_seqno = ntohl(bcast_packet->seqno);

	spin_unlock_bh(&bat_priv->orig_hash_lock);
	/* rebroadcast packet */
	add_bcast_packet_to_list(bat_priv, skb);

	/* broadcast for me */
	interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size);

	return NET_RX_SUCCESS;
}

int recv_vis_packet(struct sk_buff *skb, struct batman_if *recv_if)
{
	struct vis_packet *vis_packet;
	struct ethhdr *ethhdr;
	struct bat_priv *bat_priv = netdev_priv(recv_if->soft_iface);
	int hdr_size = sizeof(struct vis_packet);

	/* keep skb linear */
	if (skb_linearize(skb) < 0)
		return NET_RX_DROP;

	if (unlikely(!pskb_may_pull(skb, hdr_size)))
		return NET_RX_DROP;

	vis_packet = (struct vis_packet *)skb->data;
	ethhdr = (struct ethhdr *)skb_mac_header(skb);

	/* not for me */
	if (!is_my_mac(ethhdr->h_dest))
		return NET_RX_DROP;

	/* ignore own packets */
	if (is_my_mac(vis_packet->vis_orig))
		return NET_RX_DROP;

	if (is_my_mac(vis_packet->sender_orig))
		return NET_RX_DROP;

	switch (vis_packet->vis_type) {
	case VIS_TYPE_SERVER_SYNC:
		receive_server_sync_packet(bat_priv, vis_packet,
					   skb_headlen(skb));
		break;

	case VIS_TYPE_CLIENT_UPDATE:
		receive_client_update_packet(bat_priv, vis_packet,
					     skb_headlen(skb));
		break;

	default:	/* ignore unknown packet */
		break;
	}

	/* We take a copy of the data in the packet, so we should
	   always free the skbuf. */
	return NET_RX_DROP;
}