net/batman-adv/bat_iv_ogm.c - SHIFTPHONES/kernel/shift/mainline - Gitiles

 /*
  * 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 "bat_ogm.h"
 #include "translation-table.h"
 #include "ring_buffer.h"
 #include "originator.h"
 #include "routing.h"
 #include "gateway_common.h"
 #include "gateway_client.h"
 #include "hard-interface.h"
 #include "send.h"

 /* is there another aggregated packet here? */
 static int bat_ogm_aggr_packet(int buff_pos, int packet_len,
 			       int tt_num_changes)
 {
 	int next_buff_pos = buff_pos + BATMAN_OGM_LEN + tt_len(tt_num_changes);

 	return (next_buff_pos <= packet_len) &&
 		(next_buff_pos <= MAX_AGGREGATION_BYTES);
 }

 static void bat_ogm_orig_update(struct bat_priv *bat_priv,
 				struct orig_node *orig_node,
 				const struct ethhdr *ethhdr,
 				const struct batman_ogm_packet
 							*batman_ogm_packet,
 				struct hard_iface *if_incoming,
 				const unsigned char *tt_buff, int is_duplicate)
 {
 	struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL;
 	struct neigh_node *router = NULL;
 	struct orig_node *orig_node_tmp;
 	struct hlist_node *node;
 	uint8_t bcast_own_sum_orig, bcast_own_sum_neigh;

 	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_eth(tmp_neigh_node->addr, ethhdr->h_source) &&
 		    (tmp_neigh_node->if_incoming == if_incoming) &&
 		     atomic_inc_not_zero(&tmp_neigh_node->refcount)) {
 			if (neigh_node)
 				neigh_node_free_ref(neigh_node);
 			neigh_node = tmp_neigh_node;
 			continue;
 		}

 		if (is_duplicate)
 			continue;

 		spin_lock_bh(&tmp_neigh_node->tq_lock);
 		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);
 		spin_unlock_bh(&tmp_neigh_node->tq_lock);
 	}

 	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);

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

 	rcu_read_unlock();

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

 	spin_lock_bh(&neigh_node->tq_lock);
 	ring_buffer_set(neigh_node->tq_recv,
 			&neigh_node->tq_index,
 			batman_ogm_packet->tq);
 	neigh_node->tq_avg = ring_buffer_avg(neigh_node->tq_recv);
 	spin_unlock_bh(&neigh_node->tq_lock);

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

 	bonding_candidate_add(orig_node, neigh_node);

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

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

 	/* if the TQ is the same and the link not more symmetric we
 	 * won't consider it either */
 	if (router && (neigh_node->tq_avg == router->tq_avg)) {
 		orig_node_tmp = router->orig_node;
 		spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
 		bcast_own_sum_orig =
 			orig_node_tmp->bcast_own_sum[if_incoming->if_num];
 		spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

 		orig_node_tmp = neigh_node->orig_node;
 		spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
 		bcast_own_sum_neigh =
 			orig_node_tmp->bcast_own_sum[if_incoming->if_num];
 		spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

 		if (bcast_own_sum_orig >= bcast_own_sum_neigh)
 			goto update_tt;
 	}

 	update_route(bat_priv, orig_node, neigh_node);

 update_tt:
 	/* I have to check for transtable changes only if the OGM has been
 	 * sent through a primary interface */
 	if (((batman_ogm_packet->orig != ethhdr->h_source) &&
 	     (batman_ogm_packet->ttl > 2)) ||
 	    (batman_ogm_packet->flags & PRIMARIES_FIRST_HOP))
 		tt_update_orig(bat_priv, orig_node, tt_buff,
 			       batman_ogm_packet->tt_num_changes,
 			       batman_ogm_packet->ttvn,
 			       batman_ogm_packet->tt_crc);

 	if (orig_node->gw_flags != batman_ogm_packet->gw_flags)
 		gw_node_update(bat_priv, orig_node,
 			       batman_ogm_packet->gw_flags);

 	orig_node->gw_flags = batman_ogm_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)
 		neigh_node_free_ref(neigh_node);
 	if (router)
 		neigh_node_free_ref(router);
 }

 static int bat_ogm_calc_tq(struct orig_node *orig_node,
 			   struct orig_node *orig_neigh_node,
 			   struct batman_ogm_packet *batman_ogm_packet,
 			   struct hard_iface *if_incoming)
 {
 	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct neigh_node *neigh_node = NULL, *tmp_neigh_node;
 	struct hlist_node *node;
 	uint8_t total_count;
 	uint8_t orig_eq_count, neigh_rq_count, tq_own;
 	int tq_asym_penalty, ret = 0;

 	/* find corresponding one hop neighbor */
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(tmp_neigh_node, node,
 				 &orig_neigh_node->neigh_list, list) {

 		if (!compare_eth(tmp_neigh_node->addr, orig_neigh_node->orig))
 			continue;

 		if (tmp_neigh_node->if_incoming != if_incoming)
 			continue;

 		if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
 			continue;

 		neigh_node = tmp_neigh_node;
 		break;
 	}
 	rcu_read_unlock();

 	if (!neigh_node)
 		neigh_node = create_neighbor(orig_neigh_node,
 					     orig_neigh_node,
 					     orig_neigh_node->orig,
 					     if_incoming);

 	if (!neigh_node)
 		goto out;

 	/* if orig_node is direct neighbor update neigh_node last_valid */
 	if (orig_node == orig_neigh_node)
 		neigh_node->last_valid = jiffies;

 	orig_node->last_valid = jiffies;

 	/* find packet count of corresponding one hop neighbor */
 	spin_lock_bh(&orig_node->ogm_cnt_lock);
 	orig_eq_count = orig_neigh_node->bcast_own_sum[if_incoming->if_num];
 	neigh_rq_count = neigh_node->real_packet_count;
 	spin_unlock_bh(&orig_node->ogm_cnt_lock);

 	/* pay attention to not get a value bigger than 100 % */
 	total_count = (orig_eq_count > neigh_rq_count ?
 		       neigh_rq_count : orig_eq_count);

 	/* 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_rq_count < TQ_LOCAL_BIDRECT_RECV_MINIMUM))
 		tq_own = 0;
 	else
 		/* neigh_node->real_packet_count is never zero as we
 		 * only purge old information when getting new
 		 * information */
 		tq_own = (TQ_MAX_VALUE * total_count) /	neigh_rq_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
 	 */
 	tq_asym_penalty = TQ_MAX_VALUE - (TQ_MAX_VALUE *
 				(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
 				(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
 				(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count)) /
 					(TQ_LOCAL_WINDOW_SIZE *
 					 TQ_LOCAL_WINDOW_SIZE *
 					 TQ_LOCAL_WINDOW_SIZE);

 	batman_ogm_packet->tq = ((batman_ogm_packet->tq * tq_own
 							* 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_rq_count, tq_own,	tq_asym_penalty, batman_ogm_packet->tq);

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

 out:
 	if (neigh_node)
 		neigh_node_free_ref(neigh_node);
 	return ret;
 }

 /* 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 int bat_ogm_update_seqnos(const struct ethhdr *ethhdr,
 				 const struct batman_ogm_packet
 							*batman_ogm_packet,
 				 const struct hard_iface *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;
 	int is_duplicate = 0;
 	int32_t seq_diff;
 	int need_update = 0;
 	int set_mark, ret = -1;

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

 	spin_lock_bh(&orig_node->ogm_cnt_lock);
 	seq_diff = batman_ogm_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 out;

 	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_ogm_packet->seqno);

 		if (compare_eth(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_ogm_packet->seqno);
 		orig_node->last_real_seqno = batman_ogm_packet->seqno;
 	}

 	ret = is_duplicate;

 out:
 	spin_unlock_bh(&orig_node->ogm_cnt_lock);
 	orig_node_free_ref(orig_node);
 	return ret;
 }

 static void bat_ogm_process(const struct ethhdr *ethhdr,
 			    struct batman_ogm_packet *batman_ogm_packet,
 			    const unsigned char *tt_buff,
 			    struct hard_iface *if_incoming)
 {
 	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct hard_iface *hard_iface;
 	struct orig_node *orig_neigh_node, *orig_node;
 	struct neigh_node *router = NULL, *router_router = NULL;
 	struct neigh_node *orig_neigh_router = NULL;
 	int has_directlink_flag;
 	int is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
 	int is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
 	int 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_ogm_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_ogm_packet->packet_type != BAT_OGM)
 		return;

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

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

 	is_single_hop_neigh = (compare_eth(ethhdr->h_source,
 					   batman_ogm_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, ttvn %u, "
 		"crc %u, changes %u, td %d, TTL %d, V %d, IDF %d)\n",
 		ethhdr->h_source, if_incoming->net_dev->name,
 		if_incoming->net_dev->dev_addr, batman_ogm_packet->orig,
 		batman_ogm_packet->prev_sender, batman_ogm_packet->seqno,
 		batman_ogm_packet->ttvn, batman_ogm_packet->tt_crc,
 		batman_ogm_packet->tt_num_changes, batman_ogm_packet->tq,
 		batman_ogm_packet->ttl, batman_ogm_packet->version,
 		has_directlink_flag);

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

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

 		if (compare_eth(ethhdr->h_source,
 				hard_iface->net_dev->dev_addr))
 			is_my_addr = 1;

 		if (compare_eth(batman_ogm_packet->orig,
 				hard_iface->net_dev->dev_addr))
 			is_my_orig = 1;

 		if (compare_eth(batman_ogm_packet->prev_sender,
 				hard_iface->net_dev->dev_addr))
 			is_my_oldorig = 1;

 		if (is_broadcast_ether_addr(ethhdr->h_source))
 			is_broadcast = 1;
 	}
 	rcu_read_unlock();

 	if (batman_ogm_packet->version != COMPAT_VERSION) {
 		bat_dbg(DBG_BATMAN, bat_priv,
 			"Drop packet: incompatible batman version (%i)\n",
 			batman_ogm_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 */
 		/* save packet seqno for bidirectional check */
 		if (has_directlink_flag &&
 		    compare_eth(if_incoming->net_dev->dev_addr,
 				batman_ogm_packet->orig)) {
 			offset = if_incoming->if_num * NUM_WORDS;

 			spin_lock_bh(&orig_neigh_node->ogm_cnt_lock);
 			word = &(orig_neigh_node->bcast_own[offset]);
 			bit_mark(word,
 				 if_incoming_seqno -
 						batman_ogm_packet->seqno - 2);
 			orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
 				bit_packet_count(word);
 			spin_unlock_bh(&orig_neigh_node->ogm_cnt_lock);
 		}

 		bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: "
 			"originator packet from myself (via neighbor)\n");
 		orig_node_free_ref(orig_neigh_node);
 		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_ogm_packet->orig);
 	if (!orig_node)
 		return;

 	is_duplicate = bat_ogm_update_seqnos(ethhdr, batman_ogm_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_ogm_packet->tq == 0) {
 		bat_dbg(DBG_BATMAN, bat_priv,
 			"Drop packet: originator packet with tq equal 0\n");
 		goto out;
 	}

 	router = orig_node_get_router(orig_node);
 	if (router)
 		router_router = orig_node_get_router(router->orig_node);

 	/* avoid temporary routing loops */
 	if (router && router_router &&
 	    (compare_eth(router->addr, batman_ogm_packet->prev_sender)) &&
 	    !(compare_eth(batman_ogm_packet->orig,
 			  batman_ogm_packet->prev_sender)) &&
 	    (compare_eth(router->addr, router_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;

 	orig_neigh_router = orig_node_get_router(orig_neigh_node);

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

 	is_bidirectional = bat_ogm_calc_tq(orig_node, orig_neigh_node,
 					   batman_ogm_packet, if_incoming);

 	bonding_save_primary(orig_node, orig_neigh_node, batman_ogm_packet);

 	/* 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_ogm_packet->seqno) &&
 	      (orig_node->last_ttl - 3 <= batman_ogm_packet->ttl))))
 		bat_ogm_orig_update(bat_priv, orig_node, ethhdr,
 				    batman_ogm_packet, if_incoming,
 				    tt_buff, is_duplicate);

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

 		/* mark direct link on incoming interface */
 		schedule_forward_packet(orig_node, ethhdr, batman_ogm_packet,
 					1, 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_ogm_packet,
 				0, if_incoming);

 out_neigh:
 	if ((orig_neigh_node) && (!is_single_hop_neigh))
 		orig_node_free_ref(orig_neigh_node);
 out:
 	if (router)
 		neigh_node_free_ref(router);
 	if (router_router)
 		neigh_node_free_ref(router_router);
 	if (orig_neigh_router)
 		neigh_node_free_ref(orig_neigh_router);

 	orig_node_free_ref(orig_node);
 }

 void bat_ogm_receive(const struct ethhdr *ethhdr, unsigned char *packet_buff,
 		     int packet_len, struct hard_iface *if_incoming)
 {
 	struct batman_ogm_packet *batman_ogm_packet;
 	int buff_pos = 0;
 	unsigned char *tt_buff;

 	batman_ogm_packet = (struct batman_ogm_packet *)packet_buff;

 	/* unpack the aggregated packets and process them one by one */
 	do {
 		/* network to host order for our 32bit seqno and the
 		   orig_interval */
 		batman_ogm_packet->seqno = ntohl(batman_ogm_packet->seqno);
 		batman_ogm_packet->tt_crc = ntohs(batman_ogm_packet->tt_crc);

 		tt_buff = packet_buff + buff_pos + BATMAN_OGM_LEN;

 		bat_ogm_process(ethhdr, batman_ogm_packet,
 				tt_buff, if_incoming);

 		buff_pos += BATMAN_OGM_LEN +
 				tt_len(batman_ogm_packet->tt_num_changes);

 		batman_ogm_packet = (struct batman_ogm_packet *)
 						(packet_buff + buff_pos);
 	} while (bat_ogm_aggr_packet(buff_pos, packet_len,
 				     batman_ogm_packet->tt_num_changes));
 }
	/*
	* 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 "bat_ogm.h"
	#include "translation-table.h"
	#include "ring_buffer.h"
	#include "originator.h"
	#include "routing.h"
	#include "gateway_common.h"
	#include "gateway_client.h"
	#include "hard-interface.h"
	#include "send.h"

	/* is there another aggregated packet here? */
	static int bat_ogm_aggr_packet(int buff_pos, int packet_len,
	int tt_num_changes)
	{
	int next_buff_pos = buff_pos + BATMAN_OGM_LEN + tt_len(tt_num_changes);

	return (next_buff_pos <= packet_len) &&
	(next_buff_pos <= MAX_AGGREGATION_BYTES);
	}

	static void bat_ogm_orig_update(struct bat_priv *bat_priv,
	struct orig_node *orig_node,
	const struct ethhdr *ethhdr,
	const struct batman_ogm_packet
	*batman_ogm_packet,
	struct hard_iface *if_incoming,
	const unsigned char *tt_buff, int is_duplicate)
	{
	struct neigh_node neigh_node = NULL, tmp_neigh_node = NULL;
	struct neigh_node *router = NULL;
	struct orig_node *orig_node_tmp;
	struct hlist_node *node;
	uint8_t bcast_own_sum_orig, bcast_own_sum_neigh;

	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_eth(tmp_neigh_node->addr, ethhdr->h_source) &&
	(tmp_neigh_node->if_incoming == if_incoming) &&
	atomic_inc_not_zero(&tmp_neigh_node->refcount)) {
	if (neigh_node)
	neigh_node_free_ref(neigh_node);
	neigh_node = tmp_neigh_node;
	continue;
	}

	if (is_duplicate)
	continue;

	spin_lock_bh(&tmp_neigh_node->tq_lock);
	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);
	spin_unlock_bh(&tmp_neigh_node->tq_lock);
	}

	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);

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

	rcu_read_unlock();

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

	spin_lock_bh(&neigh_node->tq_lock);
	ring_buffer_set(neigh_node->tq_recv,
	&neigh_node->tq_index,
	batman_ogm_packet->tq);
	neigh_node->tq_avg = ring_buffer_avg(neigh_node->tq_recv);
	spin_unlock_bh(&neigh_node->tq_lock);

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

	bonding_candidate_add(orig_node, neigh_node);

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

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

	/* if the TQ is the same and the link not more symmetric we
	* won't consider it either */
	if (router && (neigh_node->tq_avg == router->tq_avg)) {
	orig_node_tmp = router->orig_node;
	spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
	bcast_own_sum_orig =
	orig_node_tmp->bcast_own_sum[if_incoming->if_num];
	spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

	orig_node_tmp = neigh_node->orig_node;
	spin_lock_bh(&orig_node_tmp->ogm_cnt_lock);
	bcast_own_sum_neigh =
	orig_node_tmp->bcast_own_sum[if_incoming->if_num];
	spin_unlock_bh(&orig_node_tmp->ogm_cnt_lock);

	if (bcast_own_sum_orig >= bcast_own_sum_neigh)
	goto update_tt;
	}

	update_route(bat_priv, orig_node, neigh_node);

	update_tt:
	/* I have to check for transtable changes only if the OGM has been
	* sent through a primary interface */
	if (((batman_ogm_packet->orig != ethhdr->h_source) &&
	(batman_ogm_packet->ttl > 2)) \|\|
	(batman_ogm_packet->flags & PRIMARIES_FIRST_HOP))
	tt_update_orig(bat_priv, orig_node, tt_buff,
	batman_ogm_packet->tt_num_changes,
	batman_ogm_packet->ttvn,
	batman_ogm_packet->tt_crc);

	if (orig_node->gw_flags != batman_ogm_packet->gw_flags)
	gw_node_update(bat_priv, orig_node,
	batman_ogm_packet->gw_flags);

	orig_node->gw_flags = batman_ogm_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)
	neigh_node_free_ref(neigh_node);
	if (router)
	neigh_node_free_ref(router);
	}

	static int bat_ogm_calc_tq(struct orig_node *orig_node,
	struct orig_node *orig_neigh_node,
	struct batman_ogm_packet *batman_ogm_packet,
	struct hard_iface *if_incoming)
	{
	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct neigh_node neigh_node = NULL, tmp_neigh_node;
	struct hlist_node *node;
	uint8_t total_count;
	uint8_t orig_eq_count, neigh_rq_count, tq_own;
	int tq_asym_penalty, ret = 0;

	/* find corresponding one hop neighbor */
	rcu_read_lock();
	hlist_for_each_entry_rcu(tmp_neigh_node, node,
	&orig_neigh_node->neigh_list, list) {

	if (!compare_eth(tmp_neigh_node->addr, orig_neigh_node->orig))
	continue;

	if (tmp_neigh_node->if_incoming != if_incoming)
	continue;

	if (!atomic_inc_not_zero(&tmp_neigh_node->refcount))
	continue;

	neigh_node = tmp_neigh_node;
	break;
	}
	rcu_read_unlock();

	if (!neigh_node)
	neigh_node = create_neighbor(orig_neigh_node,
	orig_neigh_node,
	orig_neigh_node->orig,
	if_incoming);

	if (!neigh_node)
	goto out;

	/* if orig_node is direct neighbor update neigh_node last_valid */
	if (orig_node == orig_neigh_node)
	neigh_node->last_valid = jiffies;

	orig_node->last_valid = jiffies;

	/* find packet count of corresponding one hop neighbor */
	spin_lock_bh(&orig_node->ogm_cnt_lock);
	orig_eq_count = orig_neigh_node->bcast_own_sum[if_incoming->if_num];
	neigh_rq_count = neigh_node->real_packet_count;
	spin_unlock_bh(&orig_node->ogm_cnt_lock);

	/* pay attention to not get a value bigger than 100 % */
	total_count = (orig_eq_count > neigh_rq_count ?
	neigh_rq_count : orig_eq_count);

	/* 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_rq_count < TQ_LOCAL_BIDRECT_RECV_MINIMUM))
	tq_own = 0;
	else
	/* neigh_node->real_packet_count is never zero as we
	* only purge old information when getting new
	* information */
	tq_own = (TQ_MAX_VALUE * total_count) / neigh_rq_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
	*/
	tq_asym_penalty = TQ_MAX_VALUE - (TQ_MAX_VALUE *
	(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
	(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count) *
	(TQ_LOCAL_WINDOW_SIZE - neigh_rq_count)) /
	(TQ_LOCAL_WINDOW_SIZE *
	TQ_LOCAL_WINDOW_SIZE *
	TQ_LOCAL_WINDOW_SIZE);

	batman_ogm_packet->tq = ((batman_ogm_packet->tq * tq_own
	* 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_rq_count, tq_own, tq_asym_penalty, batman_ogm_packet->tq);

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

	out:
	if (neigh_node)
	neigh_node_free_ref(neigh_node);
	return ret;
	}

	/* 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 int bat_ogm_update_seqnos(const struct ethhdr *ethhdr,
	const struct batman_ogm_packet
	*batman_ogm_packet,
	const struct hard_iface *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;
	int is_duplicate = 0;
	int32_t seq_diff;
	int need_update = 0;
	int set_mark, ret = -1;

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

	spin_lock_bh(&orig_node->ogm_cnt_lock);
	seq_diff = batman_ogm_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 out;

	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_ogm_packet->seqno);

	if (compare_eth(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_ogm_packet->seqno);
	orig_node->last_real_seqno = batman_ogm_packet->seqno;
	}

	ret = is_duplicate;

	out:
	spin_unlock_bh(&orig_node->ogm_cnt_lock);
	orig_node_free_ref(orig_node);
	return ret;
	}

	static void bat_ogm_process(const struct ethhdr *ethhdr,
	struct batman_ogm_packet *batman_ogm_packet,
	const unsigned char *tt_buff,
	struct hard_iface *if_incoming)
	{
	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct hard_iface *hard_iface;
	struct orig_node orig_neigh_node, orig_node;
	struct neigh_node router = NULL, router_router = NULL;
	struct neigh_node *orig_neigh_router = NULL;
	int has_directlink_flag;
	int is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0;
	int is_broadcast = 0, is_bidirectional, is_single_hop_neigh;
	int 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_ogm_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_ogm_packet->packet_type != BAT_OGM)
	return;

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

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

	is_single_hop_neigh = (compare_eth(ethhdr->h_source,
	batman_ogm_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, ttvn %u, "
	"crc %u, changes %u, td %d, TTL %d, V %d, IDF %d)\n",
	ethhdr->h_source, if_incoming->net_dev->name,
	if_incoming->net_dev->dev_addr, batman_ogm_packet->orig,
	batman_ogm_packet->prev_sender, batman_ogm_packet->seqno,
	batman_ogm_packet->ttvn, batman_ogm_packet->tt_crc,
	batman_ogm_packet->tt_num_changes, batman_ogm_packet->tq,
	batman_ogm_packet->ttl, batman_ogm_packet->version,
	has_directlink_flag);

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

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

	if (compare_eth(ethhdr->h_source,
	hard_iface->net_dev->dev_addr))
	is_my_addr = 1;

	if (compare_eth(batman_ogm_packet->orig,
	hard_iface->net_dev->dev_addr))
	is_my_orig = 1;

	if (compare_eth(batman_ogm_packet->prev_sender,
	hard_iface->net_dev->dev_addr))
	is_my_oldorig = 1;

	if (is_broadcast_ether_addr(ethhdr->h_source))
	is_broadcast = 1;
	}
	rcu_read_unlock();

	if (batman_ogm_packet->version != COMPAT_VERSION) {
	bat_dbg(DBG_BATMAN, bat_priv,
	"Drop packet: incompatible batman version (%i)\n",
	batman_ogm_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 */
	/* save packet seqno for bidirectional check */
	if (has_directlink_flag &&
	compare_eth(if_incoming->net_dev->dev_addr,
	batman_ogm_packet->orig)) {
	offset = if_incoming->if_num * NUM_WORDS;

	spin_lock_bh(&orig_neigh_node->ogm_cnt_lock);
	word = &(orig_neigh_node->bcast_own[offset]);
	bit_mark(word,
	if_incoming_seqno -
	batman_ogm_packet->seqno - 2);
	orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
	bit_packet_count(word);
	spin_unlock_bh(&orig_neigh_node->ogm_cnt_lock);
	}

	bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: "
	"originator packet from myself (via neighbor)\n");
	orig_node_free_ref(orig_neigh_node);
	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_ogm_packet->orig);
	if (!orig_node)
	return;

	is_duplicate = bat_ogm_update_seqnos(ethhdr, batman_ogm_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_ogm_packet->tq == 0) {
	bat_dbg(DBG_BATMAN, bat_priv,
	"Drop packet: originator packet with tq equal 0\n");
	goto out;
	}

	router = orig_node_get_router(orig_node);
	if (router)
	router_router = orig_node_get_router(router->orig_node);

	/* avoid temporary routing loops */
	if (router && router_router &&
	(compare_eth(router->addr, batman_ogm_packet->prev_sender)) &&
	!(compare_eth(batman_ogm_packet->orig,
	batman_ogm_packet->prev_sender)) &&
	(compare_eth(router->addr, router_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;

	orig_neigh_router = orig_node_get_router(orig_neigh_node);

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

	is_bidirectional = bat_ogm_calc_tq(orig_node, orig_neigh_node,
	batman_ogm_packet, if_incoming);

	bonding_save_primary(orig_node, orig_neigh_node, batman_ogm_packet);

	/* 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_ogm_packet->seqno) &&
	(orig_node->last_ttl - 3 <= batman_ogm_packet->ttl))))
	bat_ogm_orig_update(bat_priv, orig_node, ethhdr,
	batman_ogm_packet, if_incoming,
	tt_buff, is_duplicate);

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

	/* mark direct link on incoming interface */
	schedule_forward_packet(orig_node, ethhdr, batman_ogm_packet,
	1, 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_ogm_packet,
	0, if_incoming);

	out_neigh:
	if ((orig_neigh_node) && (!is_single_hop_neigh))
	orig_node_free_ref(orig_neigh_node);
	out:
	if (router)
	neigh_node_free_ref(router);
	if (router_router)
	neigh_node_free_ref(router_router);
	if (orig_neigh_router)
	neigh_node_free_ref(orig_neigh_router);

	orig_node_free_ref(orig_node);
	}

	void bat_ogm_receive(const struct ethhdr ethhdr, unsigned char packet_buff,
	int packet_len, struct hard_iface *if_incoming)
	{
	struct batman_ogm_packet *batman_ogm_packet;
	int buff_pos = 0;
	unsigned char *tt_buff;

	batman_ogm_packet = (struct batman_ogm_packet *)packet_buff;

	/* unpack the aggregated packets and process them one by one */
	do {
	/* network to host order for our 32bit seqno and the
	orig_interval */
	batman_ogm_packet->seqno = ntohl(batman_ogm_packet->seqno);
	batman_ogm_packet->tt_crc = ntohs(batman_ogm_packet->tt_crc);

	tt_buff = packet_buff + buff_pos + BATMAN_OGM_LEN;

	bat_ogm_process(ethhdr, batman_ogm_packet,
	tt_buff, if_incoming);

	buff_pos += BATMAN_OGM_LEN +
	tt_len(batman_ogm_packet->tt_num_changes);

	batman_ogm_packet = (struct batman_ogm_packet *)
	(packet_buff + buff_pos);
	} while (bat_ogm_aggr_packet(buff_pos, packet_len,
	batman_ogm_packet->tt_num_changes));
	}