net/batman-adv/gateway_client.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
  *
  * Marek Lindner
  *
  * 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 "gateway_client.h"
 #include "gateway_common.h"
 #include "hard-interface.h"
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/udp.h>
 #include <linux/if_vlan.h>

 static void gw_node_free_ref(struct gw_node *gw_node)
 {
 	if (atomic_dec_and_test(&gw_node->refcount))
 		kfree_rcu(gw_node, rcu);
 }

 void *gw_get_selected(struct bat_priv *bat_priv)
 {
 	struct gw_node *curr_gateway_tmp;
 	struct orig_node *orig_node = NULL;

 	rcu_read_lock();
 	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 	if (!curr_gateway_tmp)
 		goto out;

 	orig_node = curr_gateway_tmp->orig_node;
 	if (!orig_node)
 		goto out;

 	if (!atomic_inc_not_zero(&orig_node->refcount))
 		orig_node = NULL;

 out:
 	rcu_read_unlock();
 	return orig_node;
 }

 void gw_deselect(struct bat_priv *bat_priv)
 {
 	struct gw_node *gw_node;

 	spin_lock_bh(&bat_priv->gw_list_lock);
 	gw_node = rcu_dereference(bat_priv->curr_gw);
 	rcu_assign_pointer(bat_priv->curr_gw, NULL);
 	spin_unlock_bh(&bat_priv->gw_list_lock);

 	if (gw_node)
 		gw_node_free_ref(gw_node);
 }

 static void gw_select(struct bat_priv *bat_priv, struct gw_node *new_gw_node)
 {
 	struct gw_node *curr_gw_node;

 	if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
 		new_gw_node = NULL;

 	spin_lock_bh(&bat_priv->gw_list_lock);
 	curr_gw_node = rcu_dereference(bat_priv->curr_gw);
 	rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
 	spin_unlock_bh(&bat_priv->gw_list_lock);

 	if (curr_gw_node)
 		gw_node_free_ref(curr_gw_node);
 }

 void gw_election(struct bat_priv *bat_priv)
 {
 	struct hlist_node *node;
 	struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL;
 	uint8_t max_tq = 0;
 	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
 	int down, up;

 	/**
 	 * The batman daemon checks here if we already passed a full originator
 	 * cycle in order to make sure we don't choose the first gateway we
 	 * hear about. This check is based on the daemon's uptime which we
 	 * don't have.
 	 **/
 	if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
 		return;

 	rcu_read_lock();
 	curr_gw = rcu_dereference(bat_priv->curr_gw);
 	if (curr_gw) {
 		rcu_read_unlock();
 		return;
 	}

 	if (hlist_empty(&bat_priv->gw_list)) {

 		if (curr_gw) {
 			rcu_read_unlock();
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Removing selected gateway - "
 				"no gateway in range\n");
 			gw_deselect(bat_priv);
 		} else
 			rcu_read_unlock();

 		return;
 	}

 	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 		if (!gw_node->orig_node->router)
 			continue;

 		if (gw_node->deleted)
 			continue;

 		switch (atomic_read(&bat_priv->gw_sel_class)) {
 		case 1: /* fast connection */
 			gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
 					     &down, &up);

 			tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
 					 gw_node->orig_node->router->tq_avg *
 					 down * 100 * 100) /
 					 (TQ_LOCAL_WINDOW_SIZE *
 					 TQ_LOCAL_WINDOW_SIZE * 64);

 			if ((tmp_gw_factor > max_gw_factor) ||
 			    ((tmp_gw_factor == max_gw_factor) &&
 			     (gw_node->orig_node->router->tq_avg > max_tq)))
 				curr_gw_tmp = gw_node;
 			break;

 		default: /**
 			  * 2:  stable connection (use best statistic)
 			  * 3:  fast-switch (use best statistic but change as
 			  *     soon as a better gateway appears)
 			  * XX: late-switch (use best statistic but change as
 			  *     soon as a better gateway appears which has
 			  *     $routing_class more tq points)
 			  **/
 			if (gw_node->orig_node->router->tq_avg > max_tq)
 				curr_gw_tmp = gw_node;
 			break;
 		}

 		if (gw_node->orig_node->router->tq_avg > max_tq)
 			max_tq = gw_node->orig_node->router->tq_avg;

 		if (tmp_gw_factor > max_gw_factor)
 			max_gw_factor = tmp_gw_factor;
 	}

 	if (curr_gw != curr_gw_tmp) {
 		if ((curr_gw) && (!curr_gw_tmp))
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Removing selected gateway - "
 				"no gateway in range\n");
 		else if ((!curr_gw) && (curr_gw_tmp))
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Adding route to gateway %pM "
 				"(gw_flags: %i, tq: %i)\n",
 				curr_gw_tmp->orig_node->orig,
 				curr_gw_tmp->orig_node->gw_flags,
 				curr_gw_tmp->orig_node->router->tq_avg);
 		else
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Changing route to gateway %pM "
 				"(gw_flags: %i, tq: %i)\n",
 				curr_gw_tmp->orig_node->orig,
 				curr_gw_tmp->orig_node->gw_flags,
 				curr_gw_tmp->orig_node->router->tq_avg);

 		gw_select(bat_priv, curr_gw_tmp);
 	}

 	rcu_read_unlock();
 }

 void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node)
 {
 	struct gw_node *curr_gateway_tmp;
 	uint8_t gw_tq_avg, orig_tq_avg;

 	rcu_read_lock();
 	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
 	if (!curr_gateway_tmp)
 		goto out_rcu;

 	if (!curr_gateway_tmp->orig_node)
 		goto deselect_rcu;

 	if (!curr_gateway_tmp->orig_node->router)
 		goto deselect_rcu;

 	/* this node already is the gateway */
 	if (curr_gateway_tmp->orig_node == orig_node)
 		goto out_rcu;

 	if (!orig_node->router)
 		goto out_rcu;

 	gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
 	rcu_read_unlock();

 	orig_tq_avg = orig_node->router->tq_avg;

 	/* the TQ value has to be better */
 	if (orig_tq_avg < gw_tq_avg)
 		goto out;

 	/**
 	 * if the routing class is greater than 3 the value tells us how much
 	 * greater the TQ value of the new gateway must be
 	 **/
 	if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
 	    (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
 		goto out;

 	bat_dbg(DBG_BATMAN, bat_priv,
 		"Restarting gateway selection: better gateway found (tq curr: "
 		"%i, tq new: %i)\n",
 		gw_tq_avg, orig_tq_avg);
 	goto deselect;

 out_rcu:
 	rcu_read_unlock();
 	goto out;
 deselect_rcu:
 	rcu_read_unlock();
 deselect:
 	gw_deselect(bat_priv);
 out:
 	return;
 }

 static void gw_node_add(struct bat_priv *bat_priv,
 			struct orig_node *orig_node, uint8_t new_gwflags)
 {
 	struct gw_node *gw_node;
 	int down, up;

 	gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
 	if (!gw_node)
 		return;

 	memset(gw_node, 0, sizeof(struct gw_node));
 	INIT_HLIST_NODE(&gw_node->list);
 	gw_node->orig_node = orig_node;
 	atomic_set(&gw_node->refcount, 1);

 	spin_lock_bh(&bat_priv->gw_list_lock);
 	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
 	spin_unlock_bh(&bat_priv->gw_list_lock);

 	gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 	bat_dbg(DBG_BATMAN, bat_priv,
 		"Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
 		orig_node->orig, new_gwflags,
 		(down > 2048 ? down / 1024 : down),
 		(down > 2048 ? "MBit" : "KBit"),
 		(up > 2048 ? up / 1024 : up),
 		(up > 2048 ? "MBit" : "KBit"));
 }

 void gw_node_update(struct bat_priv *bat_priv,
 		    struct orig_node *orig_node, uint8_t new_gwflags)
 {
 	struct hlist_node *node;
 	struct gw_node *gw_node;

 	rcu_read_lock();
 	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 		if (gw_node->orig_node != orig_node)
 			continue;

 		bat_dbg(DBG_BATMAN, bat_priv,
 			"Gateway class of originator %pM changed from "
 			"%i to %i\n",
 			orig_node->orig, gw_node->orig_node->gw_flags,
 			new_gwflags);

 		gw_node->deleted = 0;

 		if (new_gwflags == 0) {
 			gw_node->deleted = jiffies;
 			bat_dbg(DBG_BATMAN, bat_priv,
 				"Gateway %pM removed from gateway list\n",
 				orig_node->orig);

 			if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
 				rcu_read_unlock();
 				gw_deselect(bat_priv);
 				return;
 			}
 		}

 		rcu_read_unlock();
 		return;
 	}
 	rcu_read_unlock();

 	if (new_gwflags == 0)
 		return;

 	gw_node_add(bat_priv, orig_node, new_gwflags);
 }

 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node)
 {
 	return gw_node_update(bat_priv, orig_node, 0);
 }

 void gw_node_purge(struct bat_priv *bat_priv)
 {
 	struct gw_node *gw_node;
 	struct hlist_node *node, *node_tmp;
 	unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;

 	spin_lock_bh(&bat_priv->gw_list_lock);

 	hlist_for_each_entry_safe(gw_node, node, node_tmp,
 				  &bat_priv->gw_list, list) {
 		if (((!gw_node->deleted) ||
 		     (time_before(jiffies, gw_node->deleted + timeout))) &&
 		    atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
 			continue;

 		if (rcu_dereference(bat_priv->curr_gw) == gw_node)
 			gw_deselect(bat_priv);

 		hlist_del_rcu(&gw_node->list);
 		gw_node_free_ref(gw_node);
 	}


 	spin_unlock_bh(&bat_priv->gw_list_lock);
 }

 static int _write_buffer_text(struct bat_priv *bat_priv,
 			      struct seq_file *seq, struct gw_node *gw_node)
 {
 	struct gw_node *curr_gw;
 	int down, up, ret;

 	gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);

 	rcu_read_lock();
 	curr_gw = rcu_dereference(bat_priv->curr_gw);

 	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
 		       (curr_gw == gw_node ? "=>" : "  "),
 		       gw_node->orig_node->orig,
 		       gw_node->orig_node->router->tq_avg,
 		       gw_node->orig_node->router->addr,
 		       gw_node->orig_node->router->if_incoming->net_dev->name,
 		       gw_node->orig_node->gw_flags,
 		       (down > 2048 ? down / 1024 : down),
 		       (down > 2048 ? "MBit" : "KBit"),
 		       (up > 2048 ? up / 1024 : up),
 		       (up > 2048 ? "MBit" : "KBit"));

 	rcu_read_unlock();
 	return ret;
 }

 int gw_client_seq_print_text(struct seq_file *seq, void *offset)
 {
 	struct net_device *net_dev = (struct net_device *)seq->private;
 	struct bat_priv *bat_priv = netdev_priv(net_dev);
 	struct gw_node *gw_node;
 	struct hlist_node *node;
 	int gw_count = 0;

 	if (!bat_priv->primary_if) {

 		return seq_printf(seq, "BATMAN mesh %s disabled - please "
 				  "specify interfaces to enable it\n",
 				  net_dev->name);
 	}

 	if (bat_priv->primary_if->if_status != IF_ACTIVE) {

 		return seq_printf(seq, "BATMAN mesh %s disabled - "
 				       "primary interface not active\n",
 				       net_dev->name);
 	}

 	seq_printf(seq, "      %-12s (%s/%i) %17s [%10s]: gw_class ... "
 		   "[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
 		   "Gateway", "#", TQ_MAX_VALUE, "Nexthop",
 		   "outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
 		   bat_priv->primary_if->net_dev->name,
 		   bat_priv->primary_if->net_dev->dev_addr, net_dev->name);

 	rcu_read_lock();
 	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
 		if (gw_node->deleted)
 			continue;

 		if (!gw_node->orig_node->router)
 			continue;

 		_write_buffer_text(bat_priv, seq, gw_node);
 		gw_count++;
 	}
 	rcu_read_unlock();

 	if (gw_count == 0)
 		seq_printf(seq, "No gateways in range ...\n");

 	return 0;
 }

 int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb)
 {
 	struct ethhdr *ethhdr;
 	struct iphdr *iphdr;
 	struct ipv6hdr *ipv6hdr;
 	struct udphdr *udphdr;
 	unsigned int header_len = 0;

 	if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
 		return 0;

 	/* check for ethernet header */
 	if (!pskb_may_pull(skb, header_len + ETH_HLEN))
 		return 0;
 	ethhdr = (struct ethhdr *)skb->data;
 	header_len += ETH_HLEN;

 	/* check for initial vlan header */
 	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
 		if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
 			return 0;
 		ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
 		header_len += VLAN_HLEN;
 	}

 	/* check for ip header */
 	switch (ntohs(ethhdr->h_proto)) {
 	case ETH_P_IP:
 		if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
 			return 0;
 		iphdr = (struct iphdr *)(skb->data + header_len);
 		header_len += iphdr->ihl * 4;

 		/* check for udp header */
 		if (iphdr->protocol != IPPROTO_UDP)
 			return 0;

 		break;
 	case ETH_P_IPV6:
 		if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
 			return 0;
 		ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
 		header_len += sizeof(struct ipv6hdr);

 		/* check for udp header */
 		if (ipv6hdr->nexthdr != IPPROTO_UDP)
 			return 0;

 		break;
 	default:
 		return 0;
 	}

 	if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
 		return 0;
 	udphdr = (struct udphdr *)(skb->data + header_len);
 	header_len += sizeof(struct udphdr);

 	/* check for bootp port */
 	if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
 	     (ntohs(udphdr->dest) != 67))
 		return 0;

 	if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
 	    (ntohs(udphdr->dest) != 547))
 		return 0;

 	if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
 		return -1;

 	rcu_read_lock();
 	if (!rcu_dereference(bat_priv->curr_gw)) {
 		rcu_read_unlock();
 		return 0;
 	}
 	rcu_read_unlock();

 	return 1;
 }
	/*
	* Copyright (C) 2009-2011 B.A.T.M.A.N. contributors:
	*
	* Marek Lindner
	*
	* 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 "gateway_client.h"
	#include "gateway_common.h"
	#include "hard-interface.h"
	#include <linux/ip.h>
	#include <linux/ipv6.h>
	#include <linux/udp.h>
	#include <linux/if_vlan.h>

	static void gw_node_free_ref(struct gw_node *gw_node)
	{
	if (atomic_dec_and_test(&gw_node->refcount))
	kfree_rcu(gw_node, rcu);
	}

	void gw_get_selected(struct bat_priv bat_priv)
	{
	struct gw_node *curr_gateway_tmp;
	struct orig_node *orig_node = NULL;

	rcu_read_lock();
	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
	if (!curr_gateway_tmp)
	goto out;

	orig_node = curr_gateway_tmp->orig_node;
	if (!orig_node)
	goto out;

	if (!atomic_inc_not_zero(&orig_node->refcount))
	orig_node = NULL;

	out:
	rcu_read_unlock();
	return orig_node;
	}

	void gw_deselect(struct bat_priv *bat_priv)
	{
	struct gw_node *gw_node;

	spin_lock_bh(&bat_priv->gw_list_lock);
	gw_node = rcu_dereference(bat_priv->curr_gw);
	rcu_assign_pointer(bat_priv->curr_gw, NULL);
	spin_unlock_bh(&bat_priv->gw_list_lock);

	if (gw_node)
	gw_node_free_ref(gw_node);
	}

	static void gw_select(struct bat_priv bat_priv, struct gw_node new_gw_node)
	{
	struct gw_node *curr_gw_node;

	if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
	new_gw_node = NULL;

	spin_lock_bh(&bat_priv->gw_list_lock);
	curr_gw_node = rcu_dereference(bat_priv->curr_gw);
	rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);
	spin_unlock_bh(&bat_priv->gw_list_lock);

	if (curr_gw_node)
	gw_node_free_ref(curr_gw_node);
	}

	void gw_election(struct bat_priv *bat_priv)
	{
	struct hlist_node *node;
	struct gw_node gw_node, curr_gw, *curr_gw_tmp = NULL;
	uint8_t max_tq = 0;
	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
	int down, up;

	/**
	* The batman daemon checks here if we already passed a full originator
	* cycle in order to make sure we don't choose the first gateway we
	* hear about. This check is based on the daemon's uptime which we
	* don't have.
	**/
	if (atomic_read(&bat_priv->gw_mode) != GW_MODE_CLIENT)
	return;

	rcu_read_lock();
	curr_gw = rcu_dereference(bat_priv->curr_gw);
	if (curr_gw) {
	rcu_read_unlock();
	return;
	}

	if (hlist_empty(&bat_priv->gw_list)) {

	if (curr_gw) {
	rcu_read_unlock();
	bat_dbg(DBG_BATMAN, bat_priv,
	"Removing selected gateway - "
	"no gateway in range\n");
	gw_deselect(bat_priv);
	} else
	rcu_read_unlock();

	return;
	}

	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
	if (!gw_node->orig_node->router)
	continue;

	if (gw_node->deleted)
	continue;

	switch (atomic_read(&bat_priv->gw_sel_class)) {
	case 1: /* fast connection */
	gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags,
	&down, &up);

	tmp_gw_factor = (gw_node->orig_node->router->tq_avg *
	gw_node->orig_node->router->tq_avg *
	down * 100 * 100) /
	(TQ_LOCAL_WINDOW_SIZE *
	TQ_LOCAL_WINDOW_SIZE * 64);

	if ((tmp_gw_factor > max_gw_factor) \|\|
	((tmp_gw_factor == max_gw_factor) &&
	(gw_node->orig_node->router->tq_avg > max_tq)))
	curr_gw_tmp = gw_node;
	break;

	default: /**
	* 2: stable connection (use best statistic)
	* 3: fast-switch (use best statistic but change as
	* soon as a better gateway appears)
	* XX: late-switch (use best statistic but change as
	* soon as a better gateway appears which has
	* $routing_class more tq points)
	**/
	if (gw_node->orig_node->router->tq_avg > max_tq)
	curr_gw_tmp = gw_node;
	break;
	}

	if (gw_node->orig_node->router->tq_avg > max_tq)
	max_tq = gw_node->orig_node->router->tq_avg;

	if (tmp_gw_factor > max_gw_factor)
	max_gw_factor = tmp_gw_factor;
	}

	if (curr_gw != curr_gw_tmp) {
	if ((curr_gw) && (!curr_gw_tmp))
	bat_dbg(DBG_BATMAN, bat_priv,
	"Removing selected gateway - "
	"no gateway in range\n");
	else if ((!curr_gw) && (curr_gw_tmp))
	bat_dbg(DBG_BATMAN, bat_priv,
	"Adding route to gateway %pM "
	"(gw_flags: %i, tq: %i)\n",
	curr_gw_tmp->orig_node->orig,
	curr_gw_tmp->orig_node->gw_flags,
	curr_gw_tmp->orig_node->router->tq_avg);
	else
	bat_dbg(DBG_BATMAN, bat_priv,
	"Changing route to gateway %pM "
	"(gw_flags: %i, tq: %i)\n",
	curr_gw_tmp->orig_node->orig,
	curr_gw_tmp->orig_node->gw_flags,
	curr_gw_tmp->orig_node->router->tq_avg);

	gw_select(bat_priv, curr_gw_tmp);
	}

	rcu_read_unlock();
	}

	void gw_check_election(struct bat_priv bat_priv, struct orig_node orig_node)
	{
	struct gw_node *curr_gateway_tmp;
	uint8_t gw_tq_avg, orig_tq_avg;

	rcu_read_lock();
	curr_gateway_tmp = rcu_dereference(bat_priv->curr_gw);
	if (!curr_gateway_tmp)
	goto out_rcu;

	if (!curr_gateway_tmp->orig_node)
	goto deselect_rcu;

	if (!curr_gateway_tmp->orig_node->router)
	goto deselect_rcu;

	/* this node already is the gateway */
	if (curr_gateway_tmp->orig_node == orig_node)
	goto out_rcu;

	if (!orig_node->router)
	goto out_rcu;

	gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg;
	rcu_read_unlock();

	orig_tq_avg = orig_node->router->tq_avg;

	/* the TQ value has to be better */
	if (orig_tq_avg < gw_tq_avg)
	goto out;

	/**
	* if the routing class is greater than 3 the value tells us how much
	* greater the TQ value of the new gateway must be
	**/
	if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
	(orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
	goto out;

	bat_dbg(DBG_BATMAN, bat_priv,
	"Restarting gateway selection: better gateway found (tq curr: "
	"%i, tq new: %i)\n",
	gw_tq_avg, orig_tq_avg);
	goto deselect;

	out_rcu:
	rcu_read_unlock();
	goto out;
	deselect_rcu:
	rcu_read_unlock();
	deselect:
	gw_deselect(bat_priv);
	out:
	return;
	}

	static void gw_node_add(struct bat_priv *bat_priv,
	struct orig_node *orig_node, uint8_t new_gwflags)
	{
	struct gw_node *gw_node;
	int down, up;

	gw_node = kmalloc(sizeof(struct gw_node), GFP_ATOMIC);
	if (!gw_node)
	return;

	memset(gw_node, 0, sizeof(struct gw_node));
	INIT_HLIST_NODE(&gw_node->list);
	gw_node->orig_node = orig_node;
	atomic_set(&gw_node->refcount, 1);

	spin_lock_bh(&bat_priv->gw_list_lock);
	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
	spin_unlock_bh(&bat_priv->gw_list_lock);

	gw_bandwidth_to_kbit(new_gwflags, &down, &up);
	bat_dbg(DBG_BATMAN, bat_priv,
	"Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
	orig_node->orig, new_gwflags,
	(down > 2048 ? down / 1024 : down),
	(down > 2048 ? "MBit" : "KBit"),
	(up > 2048 ? up / 1024 : up),
	(up > 2048 ? "MBit" : "KBit"));
	}

	void gw_node_update(struct bat_priv *bat_priv,
	struct orig_node *orig_node, uint8_t new_gwflags)
	{
	struct hlist_node *node;
	struct gw_node *gw_node;

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
	if (gw_node->orig_node != orig_node)
	continue;

	bat_dbg(DBG_BATMAN, bat_priv,
	"Gateway class of originator %pM changed from "
	"%i to %i\n",
	orig_node->orig, gw_node->orig_node->gw_flags,
	new_gwflags);

	gw_node->deleted = 0;

	if (new_gwflags == 0) {
	gw_node->deleted = jiffies;
	bat_dbg(DBG_BATMAN, bat_priv,
	"Gateway %pM removed from gateway list\n",
	orig_node->orig);

	if (gw_node == rcu_dereference(bat_priv->curr_gw)) {
	rcu_read_unlock();
	gw_deselect(bat_priv);
	return;
	}
	}

	rcu_read_unlock();
	return;
	}
	rcu_read_unlock();

	if (new_gwflags == 0)
	return;

	gw_node_add(bat_priv, orig_node, new_gwflags);
	}

	void gw_node_delete(struct bat_priv bat_priv, struct orig_node orig_node)
	{
	return gw_node_update(bat_priv, orig_node, 0);
	}

	void gw_node_purge(struct bat_priv *bat_priv)
	{
	struct gw_node *gw_node;
	struct hlist_node node, node_tmp;
	unsigned long timeout = 2 * PURGE_TIMEOUT * HZ;

	spin_lock_bh(&bat_priv->gw_list_lock);

	hlist_for_each_entry_safe(gw_node, node, node_tmp,
	&bat_priv->gw_list, list) {
	if (((!gw_node->deleted) \|\|
	(time_before(jiffies, gw_node->deleted + timeout))) &&
	atomic_read(&bat_priv->mesh_state) == MESH_ACTIVE)
	continue;

	if (rcu_dereference(bat_priv->curr_gw) == gw_node)
	gw_deselect(bat_priv);

	hlist_del_rcu(&gw_node->list);
	gw_node_free_ref(gw_node);
	}


	spin_unlock_bh(&bat_priv->gw_list_lock);
	}

	static int _write_buffer_text(struct bat_priv *bat_priv,
	struct seq_file seq, struct gw_node gw_node)
	{
	struct gw_node *curr_gw;
	int down, up, ret;

	gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);

	rcu_read_lock();
	curr_gw = rcu_dereference(bat_priv->curr_gw);

	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
	(curr_gw == gw_node ? "=>" : " "),
	gw_node->orig_node->orig,
	gw_node->orig_node->router->tq_avg,
	gw_node->orig_node->router->addr,
	gw_node->orig_node->router->if_incoming->net_dev->name,
	gw_node->orig_node->gw_flags,
	(down > 2048 ? down / 1024 : down),
	(down > 2048 ? "MBit" : "KBit"),
	(up > 2048 ? up / 1024 : up),
	(up > 2048 ? "MBit" : "KBit"));

	rcu_read_unlock();
	return ret;
	}

	int gw_client_seq_print_text(struct seq_file seq, void offset)
	{
	struct net_device net_dev = (struct net_device )seq->private;
	struct bat_priv *bat_priv = netdev_priv(net_dev);
	struct gw_node *gw_node;
	struct hlist_node *node;
	int gw_count = 0;

	if (!bat_priv->primary_if) {

	return seq_printf(seq, "BATMAN mesh %s disabled - please "
	"specify interfaces to enable it\n",
	net_dev->name);
	}

	if (bat_priv->primary_if->if_status != IF_ACTIVE) {

	return seq_printf(seq, "BATMAN mesh %s disabled - "
	"primary interface not active\n",
	net_dev->name);
	}

	seq_printf(seq, " %-12s (%s/%i) %17s [%10s]: gw_class ... "
	"[B.A.T.M.A.N. adv %s%s, MainIF/MAC: %s/%pM (%s)]\n",
	"Gateway", "#", TQ_MAX_VALUE, "Nexthop",
	"outgoingIF", SOURCE_VERSION, REVISION_VERSION_STR,
	bat_priv->primary_if->net_dev->name,
	bat_priv->primary_if->net_dev->dev_addr, net_dev->name);

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
	if (gw_node->deleted)
	continue;

	if (!gw_node->orig_node->router)
	continue;

	_write_buffer_text(bat_priv, seq, gw_node);
	gw_count++;
	}
	rcu_read_unlock();

	if (gw_count == 0)
	seq_printf(seq, "No gateways in range ...\n");

	return 0;
	}

	int gw_is_target(struct bat_priv bat_priv, struct sk_buff skb)
	{
	struct ethhdr *ethhdr;
	struct iphdr *iphdr;
	struct ipv6hdr *ipv6hdr;
	struct udphdr *udphdr;
	unsigned int header_len = 0;

	if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
	return 0;

	/* check for ethernet header */
	if (!pskb_may_pull(skb, header_len + ETH_HLEN))
	return 0;
	ethhdr = (struct ethhdr *)skb->data;
	header_len += ETH_HLEN;

	/* check for initial vlan header */
	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
	if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
	return 0;
	ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
	header_len += VLAN_HLEN;
	}

	/* check for ip header */
	switch (ntohs(ethhdr->h_proto)) {
	case ETH_P_IP:
	if (!pskb_may_pull(skb, header_len + sizeof(struct iphdr)))
	return 0;
	iphdr = (struct iphdr *)(skb->data + header_len);
	header_len += iphdr->ihl * 4;

	/* check for udp header */
	if (iphdr->protocol != IPPROTO_UDP)
	return 0;

	break;
	case ETH_P_IPV6:
	if (!pskb_may_pull(skb, header_len + sizeof(struct ipv6hdr)))
	return 0;
	ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
	header_len += sizeof(struct ipv6hdr);

	/* check for udp header */
	if (ipv6hdr->nexthdr != IPPROTO_UDP)
	return 0;

	break;
	default:
	return 0;
	}

	if (!pskb_may_pull(skb, header_len + sizeof(struct udphdr)))
	return 0;
	udphdr = (struct udphdr *)(skb->data + header_len);
	header_len += sizeof(struct udphdr);

	/* check for bootp port */
	if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
	(ntohs(udphdr->dest) != 67))
	return 0;

	if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
	(ntohs(udphdr->dest) != 547))
	return 0;

	if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
	return -1;

	rcu_read_lock();
	if (!rcu_dereference(bat_priv->curr_gw)) {
	rcu_read_unlock();
	return 0;
	}
	rcu_read_unlock();

	return 1;
	}