1 files changed, 463 insertions, 416 deletions

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index f105219f4a4b..7a11b245e9f4 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -1,48 +1,81 @@
-/* Copyright (C) 2009-2013 B.A.T.M.A.N. contributors:
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 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 "sysfs.h"
 #include "gateway_client.h"
-#include "gateway_common.h"
-#include "hard-interface.h"
-#include "originator.h"
-#include "translation-table.h"
-#include "routing.h"
+#include "main.h"
+
+#include <linux/atomic.h>
+#include <linux/byteorder/generic.h>
+#include <linux/container_of.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/etherdevice.h>
+#include <linux/gfp.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/netdevice.h>
+#include <linux/netlink.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/sprintf.h>
+#include <linux/stddef.h>
 #include <linux/udp.h>
-#include <linux/if_vlan.h>
+#include <uapi/linux/batadv_packet.h>
+#include <uapi/linux/batman_adv.h>
 
-/* This is the offset of the options field in a dhcp packet starting at
- * the beginning of the dhcp header
+#include "hard-interface.h"
+#include "log.h"
+#include "netlink.h"
+#include "originator.h"
+#include "routing.h"
+#include "translation-table.h"
+
+/* These are the offsets of the "hw type" and "hw address length" in the dhcp
+ * packet starting at the beginning of the dhcp header
+ */
+#define BATADV_DHCP_HTYPE_OFFSET	1
+#define BATADV_DHCP_HLEN_OFFSET		2
+/* Value of htype representing Ethernet */
+#define BATADV_DHCP_HTYPE_ETHERNET	0x01
+/* This is the offset of the "chaddr" field in the dhcp packet starting at the
+ * beginning of the dhcp header
  */
-#define BATADV_DHCP_OPTIONS_OFFSET 240
-#define BATADV_DHCP_REQUEST 3
+#define BATADV_DHCP_CHADDR_OFFSET	28
 
-static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
+/**
+ * batadv_gw_node_release() - release gw_node from lists and queue for free
+ *  after rcu grace period
+ * @ref: kref pointer of the gw_node
+ */
+void batadv_gw_node_release(struct kref *ref)
 {
-	if (atomic_dec_and_test(&gw_node->refcount))
-		kfree_rcu(gw_node, rcu);
+	struct batadv_gw_node *gw_node;
+
+	gw_node = container_of(ref, struct batadv_gw_node, refcount);
+
+	batadv_orig_node_put(gw_node->orig_node);
+	kfree_rcu(gw_node, rcu);
 }
 
-static struct batadv_gw_node *
+/**
+ * batadv_gw_get_selected_gw_node() - Get currently selected gateway
+ * @bat_priv: the bat priv with all the mesh interface information
+ *
+ * Return: selected gateway (with increased refcnt), NULL on errors
+ */
+struct batadv_gw_node *
 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
 {
 	struct batadv_gw_node *gw_node;
@@ -52,7 +85,7 @@ batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
 	if (!gw_node)
 		goto out;
 
-	if (!atomic_inc_not_zero(&gw_node->refcount))
+	if (!kref_get_unless_zero(&gw_node->refcount))
 		gw_node = NULL;
 
 out:
@@ -60,6 +93,12 @@ out:
 	return gw_node;
 }
 
+/**
+ * batadv_gw_get_selected_orig() - Get originator of currently selected gateway
+ * @bat_priv: the bat priv with all the mesh interface information
+ *
+ * Return: orig_node of selected gateway (with increased refcnt), NULL on errors
+ */
 struct batadv_orig_node *
 batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
 {
@@ -75,14 +114,13 @@ batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
 	if (!orig_node)
 		goto unlock;
 
-	if (!atomic_inc_not_zero(&orig_node->refcount))
+	if (!kref_get_unless_zero(&orig_node->refcount))
 		orig_node = NULL;
 
 unlock:
 	rcu_read_unlock();
 out:
-	if (gw_node)
-		batadv_gw_node_free_ref(gw_node);
+	batadv_gw_node_put(gw_node);
 	return orig_node;
 }
 
@@ -93,115 +131,81 @@ static void batadv_gw_select(struct batadv_priv *bat_priv,
 
 	spin_lock_bh(&bat_priv->gw.list_lock);
 
-	if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
-		new_gw_node = NULL;
+	if (new_gw_node)
+		kref_get(&new_gw_node->refcount);
 
-	curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
-	rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
+	curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node,
+					   true);
 
-	if (curr_gw_node)
-		batadv_gw_node_free_ref(curr_gw_node);
+	batadv_gw_node_put(curr_gw_node);
 
 	spin_unlock_bh(&bat_priv->gw.list_lock);
 }
 
-void batadv_gw_deselect(struct batadv_priv *bat_priv)
+/**
+ * batadv_gw_reselect() - force a gateway reselection
+ * @bat_priv: the bat priv with all the mesh interface information
+ *
+ * Set a flag to remind the GW component to perform a new gateway reselection.
+ * However this function does not ensure that the current gateway is going to be
+ * deselected. The reselection mechanism may elect the same gateway once again.
+ *
+ * This means that invoking batadv_gw_reselect() does not guarantee a gateway
+ * change and therefore a uevent is not necessarily expected.
+ */
+void batadv_gw_reselect(struct batadv_priv *bat_priv)
 {
 	atomic_set(&bat_priv->gw.reselect, 1);
 }
 
-static struct batadv_gw_node *
-batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
+/**
+ * batadv_gw_check_client_stop() - check if client mode has been switched off
+ * @bat_priv: the bat priv with all the mesh interface information
+ *
+ * This function assumes the caller has checked that the gw state *is actually
+ * changing*. This function is not supposed to be called when there is no state
+ * change.
+ */
+void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
 {
-	struct batadv_neigh_node *router;
-	struct batadv_gw_node *gw_node, *curr_gw = NULL;
-	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
-	uint32_t gw_divisor;
-	uint8_t max_tq = 0;
-	int down, up;
-	uint8_t tq_avg;
-	struct batadv_orig_node *orig_node;
-
-	gw_divisor = BATADV_TQ_LOCAL_WINDOW_SIZE * BATADV_TQ_LOCAL_WINDOW_SIZE;
-	gw_divisor *= 64;
-
-	rcu_read_lock();
-	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		if (gw_node->deleted)
-			continue;
-
-		orig_node = gw_node->orig_node;
-		router = batadv_orig_node_get_router(orig_node);
-		if (!router)
-			continue;
-
-		if (!atomic_inc_not_zero(&gw_node->refcount))
-			goto next;
-
-		tq_avg = router->tq_avg;
-
-		switch (atomic_read(&bat_priv->gw_sel_class)) {
-		case 1: /* fast connection */
-			batadv_gw_bandwidth_to_kbit(orig_node->gw_flags,
-						    &down, &up);
-
-			tmp_gw_factor = tq_avg * tq_avg * down * 100 * 100;
-			tmp_gw_factor /= gw_divisor;
-
-			if ((tmp_gw_factor > max_gw_factor) ||
-			    ((tmp_gw_factor == max_gw_factor) &&
-			     (tq_avg > max_tq))) {
-				if (curr_gw)
-					batadv_gw_node_free_ref(curr_gw);
-				curr_gw = gw_node;
-				atomic_inc(&curr_gw->refcount);
-			}
-			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 (tq_avg > max_tq) {
-				if (curr_gw)
-					batadv_gw_node_free_ref(curr_gw);
-				curr_gw = gw_node;
-				atomic_inc(&curr_gw->refcount);
-			}
-			break;
-		}
+	struct batadv_gw_node *curr_gw;
 
-		if (tq_avg > max_tq)
-			max_tq = tq_avg;
+	if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
+		return;
 
-		if (tmp_gw_factor > max_gw_factor)
-			max_gw_factor = tmp_gw_factor;
+	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+	if (!curr_gw)
+		return;
 
-		batadv_gw_node_free_ref(gw_node);
+	/* deselect the current gateway so that next time that client mode is
+	 * enabled a proper GW_ADD event can be sent
+	 */
+	batadv_gw_select(bat_priv, NULL);
 
-next:
-		batadv_neigh_node_free_ref(router);
-	}
-	rcu_read_unlock();
+	/* if batman-adv is switching the gw client mode off and a gateway was
+	 * already selected, send a DEL uevent
+	 */
+	batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
 
-	return curr_gw;
+	batadv_gw_node_put(curr_gw);
 }
 
+/**
+ * batadv_gw_election() - Elect the best gateway
+ * @bat_priv: the bat priv with all the mesh interface information
+ */
 void batadv_gw_election(struct batadv_priv *bat_priv)
 {
-	struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
+	struct batadv_gw_node *curr_gw = NULL;
+	struct batadv_gw_node *next_gw = NULL;
 	struct batadv_neigh_node *router = NULL;
+	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 	char gw_addr[18] = { '\0' };
 
-	/* 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) != BATADV_GW_MODE_CLIENT)
+	if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
+		goto out;
+
+	if (!bat_priv->algo_ops->gw.get_best_gw_node)
 		goto out;
 
 	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
@@ -209,7 +213,11 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
 	if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 		goto out;
 
-	next_gw = batadv_gw_get_best_gw_node(bat_priv);
+	/* if gw.reselect is set to 1 it means that a previous call to
+	 * gw.is_eligible() said that we have a new best GW, therefore it can
+	 * now be picked from the list and selected
+	 */
+	next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
 
 	if (curr_gw == next_gw)
 		goto out;
@@ -217,30 +225,46 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
 	if (next_gw) {
 		sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
 
-		router = batadv_orig_node_get_router(next_gw->orig_node);
+		router = batadv_orig_router_get(next_gw->orig_node,
+						BATADV_IF_DEFAULT);
 		if (!router) {
-			batadv_gw_deselect(bat_priv);
+			batadv_gw_reselect(bat_priv);
+			goto out;
+		}
+
+		router_ifinfo = batadv_neigh_ifinfo_get(router,
+							BATADV_IF_DEFAULT);
+		if (!router_ifinfo) {
+			batadv_gw_reselect(bat_priv);
 			goto out;
 		}
 	}
 
-	if ((curr_gw) && (!next_gw)) {
+	if (curr_gw && !next_gw) {
 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 			   "Removing selected gateway - no gateway in range\n");
 		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
 				    NULL);
-	} else if ((!curr_gw) && (next_gw)) {
+	} else if (!curr_gw && next_gw) {
 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
-			   "Adding route to gateway %pM (gw_flags: %i, tq: %i)\n",
+			   "Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 			   next_gw->orig_node->orig,
-			   next_gw->orig_node->gw_flags, router->tq_avg);
+			   next_gw->bandwidth_down / 10,
+			   next_gw->bandwidth_down % 10,
+			   next_gw->bandwidth_up / 10,
+			   next_gw->bandwidth_up % 10,
+			   router_ifinfo->bat_iv.tq_avg);
 		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
 				    gw_addr);
 	} else {
 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
-			   "Changing route to gateway %pM (gw_flags: %i, tq: %i)\n",
+			   "Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
 			   next_gw->orig_node->orig,
-			   next_gw->orig_node->gw_flags, router->tq_avg);
+			   next_gw->bandwidth_down / 10,
+			   next_gw->bandwidth_down % 10,
+			   next_gw->bandwidth_up / 10,
+			   next_gw->bandwidth_up % 10,
+			   router_ifinfo->bat_iv.tq_avg);
 		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
 				    gw_addr);
 	}
@@ -248,419 +272,433 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
 	batadv_gw_select(bat_priv, next_gw);
 
 out:
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
-	if (next_gw)
-		batadv_gw_node_free_ref(next_gw);
-	if (router)
-		batadv_neigh_node_free_ref(router);
+	batadv_gw_node_put(curr_gw);
+	batadv_gw_node_put(next_gw);
+	batadv_neigh_node_put(router);
+	batadv_neigh_ifinfo_put(router_ifinfo);
 }
 
+/**
+ * batadv_gw_check_election() - Elect orig node as best gateway when eligible
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @orig_node: orig node which is to be checked
+ */
 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 			      struct batadv_orig_node *orig_node)
 {
 	struct batadv_orig_node *curr_gw_orig;
-	struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
-	uint8_t gw_tq_avg, orig_tq_avg;
+
+	/* abort immediately if the routing algorithm does not support gateway
+	 * election
+	 */
+	if (!bat_priv->algo_ops->gw.is_eligible)
+		return;
 
 	curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 	if (!curr_gw_orig)
-		goto deselect;
-
-	router_gw = batadv_orig_node_get_router(curr_gw_orig);
-	if (!router_gw)
-		goto deselect;
+		goto reselect;
 
 	/* this node already is the gateway */
 	if (curr_gw_orig == orig_node)
 		goto out;
 
-	router_orig = batadv_orig_node_get_router(orig_node);
-	if (!router_orig)
-		goto out;
-
-	gw_tq_avg = router_gw->tq_avg;
-	orig_tq_avg = router_orig->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)))
+	if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig,
+						orig_node))
 		goto out;
 
-	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
-		   "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
-		   gw_tq_avg, orig_tq_avg);
-
-deselect:
-	batadv_gw_deselect(bat_priv);
+reselect:
+	batadv_gw_reselect(bat_priv);
 out:
-	if (curr_gw_orig)
-		batadv_orig_node_free_ref(curr_gw_orig);
-	if (router_gw)
-		batadv_neigh_node_free_ref(router_gw);
-	if (router_orig)
-		batadv_neigh_node_free_ref(router_orig);
-
-	return;
+	batadv_orig_node_put(curr_gw_orig);
 }
 
+/**
+ * batadv_gw_node_add() - add gateway node to list of available gateways
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @orig_node: originator announcing gateway capabilities
+ * @gateway: announced bandwidth information
+ *
+ * Has to be called with the appropriate locks being acquired
+ * (gw.list_lock).
+ */
 static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 			       struct batadv_orig_node *orig_node,
-			       uint8_t new_gwflags)
+			       struct batadv_tvlv_gateway_data *gateway)
 {
 	struct batadv_gw_node *gw_node;
-	int down, up;
+
+	lockdep_assert_held(&bat_priv->gw.list_lock);
+
+	if (gateway->bandwidth_down == 0)
+		return;
 
 	gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
 	if (!gw_node)
 		return;
 
+	kref_init(&gw_node->refcount);
 	INIT_HLIST_NODE(&gw_node->list);
+	kref_get(&orig_node->refcount);
 	gw_node->orig_node = orig_node;
-	atomic_set(&gw_node->refcount, 1);
+	gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
+	gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
 
-	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);
+	kref_get(&gw_node->refcount);
+	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list);
+	bat_priv->gw.generation++;
 
-	batadv_gw_bandwidth_to_kbit(new_gwflags, &down, &up);
 	batadv_dbg(BATADV_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"));
+		   "Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
+		   orig_node->orig,
+		   ntohl(gateway->bandwidth_down) / 10,
+		   ntohl(gateway->bandwidth_down) % 10,
+		   ntohl(gateway->bandwidth_up) / 10,
+		   ntohl(gateway->bandwidth_up) % 10);
+
+	/* don't return reference to new gw_node */
+	batadv_gw_node_put(gw_node);
 }
 
-void batadv_gw_node_update(struct batadv_priv *bat_priv,
-			   struct batadv_orig_node *orig_node,
-			   uint8_t new_gwflags)
+/**
+ * batadv_gw_node_get() - retrieve gateway node from list of available gateways
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @orig_node: originator announcing gateway capabilities
+ *
+ * Return: gateway node if found or NULL otherwise.
+ */
+struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
+					  struct batadv_orig_node *orig_node)
 {
-	struct batadv_gw_node *gw_node, *curr_gw;
-
-	/* Note: We don't need a NULL check here, since curr_gw never gets
-	 * dereferenced. If curr_gw is NULL we also should not exit as we may
-	 * have this gateway in our list (duplication check!) even though we
-	 * have no currently selected gateway.
-	 */
-	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+	struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
 
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		if (gw_node->orig_node != orig_node)
+	hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.gateway_list,
+				 list) {
+		if (gw_node_tmp->orig_node != orig_node)
 			continue;
 
-		batadv_dbg(BATADV_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);
+		if (!kref_get_unless_zero(&gw_node_tmp->refcount))
+			continue;
 
-		gw_node->deleted = 0;
+		gw_node = gw_node_tmp;
+		break;
+	}
+	rcu_read_unlock();
 
-		if (new_gwflags == BATADV_NO_FLAGS) {
-			gw_node->deleted = jiffies;
-			batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
-				   "Gateway %pM removed from gateway list\n",
-				   orig_node->orig);
+	return gw_node;
+}
 
-			if (gw_node == curr_gw)
-				goto deselect;
-		}
+/**
+ * batadv_gw_node_update() - update list of available gateways with changed
+ *  bandwidth information
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @orig_node: originator announcing gateway capabilities
+ * @gateway: announced bandwidth information
+ */
+void batadv_gw_node_update(struct batadv_priv *bat_priv,
+			   struct batadv_orig_node *orig_node,
+			   struct batadv_tvlv_gateway_data *gateway)
+{
+	struct batadv_gw_node *gw_node, *curr_gw = NULL;
 
-		goto unlock;
+	spin_lock_bh(&bat_priv->gw.list_lock);
+	gw_node = batadv_gw_node_get(bat_priv, orig_node);
+	if (!gw_node) {
+		batadv_gw_node_add(bat_priv, orig_node, gateway);
+		spin_unlock_bh(&bat_priv->gw.list_lock);
+		goto out;
 	}
+	spin_unlock_bh(&bat_priv->gw.list_lock);
 
-	if (new_gwflags == BATADV_NO_FLAGS)
-		goto unlock;
+	if (gw_node->bandwidth_down == ntohl(gateway->bandwidth_down) &&
+	    gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))
+		goto out;
 
-	batadv_gw_node_add(bat_priv, orig_node, new_gwflags);
-	goto unlock;
+	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+		   "Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
+		   orig_node->orig,
+		   gw_node->bandwidth_down / 10,
+		   gw_node->bandwidth_down % 10,
+		   gw_node->bandwidth_up / 10,
+		   gw_node->bandwidth_up % 10,
+		   ntohl(gateway->bandwidth_down) / 10,
+		   ntohl(gateway->bandwidth_down) % 10,
+		   ntohl(gateway->bandwidth_up) / 10,
+		   ntohl(gateway->bandwidth_up) % 10);
+
+	gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
+	gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
+
+	if (ntohl(gateway->bandwidth_down) == 0) {
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "Gateway %pM removed from gateway list\n",
+			   orig_node->orig);
 
-deselect:
-	batadv_gw_deselect(bat_priv);
-unlock:
-	rcu_read_unlock();
+		/* Note: We don't need a NULL check here, since curr_gw never
+		 * gets dereferenced.
+		 */
+		spin_lock_bh(&bat_priv->gw.list_lock);
+		if (!hlist_unhashed(&gw_node->list)) {
+			hlist_del_init_rcu(&gw_node->list);
+			batadv_gw_node_put(gw_node);
+			bat_priv->gw.generation++;
+		}
+		spin_unlock_bh(&bat_priv->gw.list_lock);
+
+		curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
+		if (gw_node == curr_gw)
+			batadv_gw_reselect(bat_priv);
 
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
+		batadv_gw_node_put(curr_gw);
+	}
+
+out:
+	batadv_gw_node_put(gw_node);
 }
 
+/**
+ * batadv_gw_node_delete() - Remove orig_node from gateway list
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @orig_node: orig node which is currently in process of being removed
+ */
 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 			   struct batadv_orig_node *orig_node)
 {
-	batadv_gw_node_update(bat_priv, orig_node, 0);
+	struct batadv_tvlv_gateway_data gateway;
+
+	gateway.bandwidth_down = 0;
+	gateway.bandwidth_up = 0;
+
+	batadv_gw_node_update(bat_priv, orig_node, &gateway);
 }
 
-void batadv_gw_node_purge(struct batadv_priv *bat_priv)
+/**
+ * batadv_gw_node_free() - Free gateway information from mesh interface
+ * @bat_priv: the bat priv with all the mesh interface information
+ */
+void batadv_gw_node_free(struct batadv_priv *bat_priv)
 {
-	struct batadv_gw_node *gw_node, *curr_gw;
+	struct batadv_gw_node *gw_node;
 	struct hlist_node *node_tmp;
-	unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
-	int do_deselect = 0;
-
-	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 
 	spin_lock_bh(&bat_priv->gw.list_lock);
-
 	hlist_for_each_entry_safe(gw_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) == BATADV_MESH_ACTIVE)
-			continue;
-
-		if (curr_gw == gw_node)
-			do_deselect = 1;
-
-		hlist_del_rcu(&gw_node->list);
-		batadv_gw_node_free_ref(gw_node);
+				  &bat_priv->gw.gateway_list, list) {
+		hlist_del_init_rcu(&gw_node->list);
+		batadv_gw_node_put(gw_node);
+		bat_priv->gw.generation++;
 	}
-
 	spin_unlock_bh(&bat_priv->gw.list_lock);
-
-	/* gw_deselect() needs to acquire the gw_list_lock */
-	if (do_deselect)
-		batadv_gw_deselect(bat_priv);
-
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
 }
 
-/* fails if orig_node has no router */
-static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
-				    struct seq_file *seq,
-				    const struct batadv_gw_node *gw_node)
+/**
+ * batadv_gw_dump() - Dump gateways into a message
+ * @msg: Netlink message to dump into
+ * @cb: Control block containing additional options
+ *
+ * Return: Error code, or length of message
+ */
+int batadv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb)
 {
-	struct batadv_gw_node *curr_gw;
-	struct batadv_neigh_node *router;
-	int down, up, ret = -1;
-
-	batadv_gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);
+	struct batadv_hard_iface *primary_if = NULL;
+	struct net_device *mesh_iface;
+	struct batadv_priv *bat_priv;
+	int ret;
 
-	router = batadv_orig_node_get_router(gw_node->orig_node);
-	if (!router)
-		goto out;
-
-	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
-
-	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
-			 (curr_gw == gw_node ? "=>" : "  "),
-			 gw_node->orig_node->orig,
-			 router->tq_avg, router->addr,
-			 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"));
-
-	batadv_neigh_node_free_ref(router);
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
-out:
-	return ret;
-}
+	mesh_iface = batadv_netlink_get_meshif(cb);
+	if (IS_ERR(mesh_iface))
+		return PTR_ERR(mesh_iface);
 
-int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
-{
-	struct net_device *net_dev = (struct net_device *)seq->private;
-	struct batadv_priv *bat_priv = netdev_priv(net_dev);
-	struct batadv_hard_iface *primary_if;
-	struct batadv_gw_node *gw_node;
-	int gw_count = 0;
+	bat_priv = netdev_priv(mesh_iface);
 
-	primary_if = batadv_seq_print_text_primary_if_get(seq);
-	if (!primary_if)
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
+		ret = -ENOENT;
 		goto out;
-
-	seq_printf(seq,
-		   "      %-12s (%s/%i) %17s [%10s]: gw_class ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
-		   "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
-		   BATADV_SOURCE_VERSION, primary_if->net_dev->name,
-		   primary_if->net_dev->dev_addr, net_dev->name);
-
-	rcu_read_lock();
-	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		if (gw_node->deleted)
-			continue;
-
-		/* fails if orig_node has no router */
-		if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
-			continue;
-
-		gw_count++;
 	}
-	rcu_read_unlock();
-
-	if (gw_count == 0)
-		seq_puts(seq, "No gateways in range ...\n");
 
-out:
-	if (primary_if)
-		batadv_hardif_free_ref(primary_if);
-	return 0;
-}
-
-static bool batadv_is_type_dhcprequest(struct sk_buff *skb, int header_len)
-{
-	int ret = false;
-	unsigned char *p;
-	int pkt_len;
-
-	if (skb_linearize(skb) < 0)
+	if (!bat_priv->algo_ops->gw.dump) {
+		ret = -EOPNOTSUPP;
 		goto out;
+	}
 
-	pkt_len = skb_headlen(skb);
-
-	if (pkt_len < header_len + BATADV_DHCP_OPTIONS_OFFSET + 1)
-		goto out;
+	bat_priv->algo_ops->gw.dump(msg, cb, bat_priv);
 
-	p = skb->data + header_len + BATADV_DHCP_OPTIONS_OFFSET;
-	pkt_len -= header_len + BATADV_DHCP_OPTIONS_OFFSET + 1;
+	ret = msg->len;
 
-	/* Access the dhcp option lists. Each entry is made up by:
-	 * - octet 1: option type
-	 * - octet 2: option data len (only if type != 255 and 0)
-	 * - octet 3: option data
-	 */
-	while (*p != 255 && !ret) {
-		/* p now points to the first octet: option type */
-		if (*p == 53) {
-			/* type 53 is the message type option.
-			 * Jump the len octet and go to the data octet
-			 */
-			if (pkt_len < 2)
-				goto out;
-			p += 2;
-
-			/* check if the message type is what we need */
-			if (*p == BATADV_DHCP_REQUEST)
-				ret = true;
-			break;
-		} else if (*p == 0) {
-			/* option type 0 (padding), just go forward */
-			if (pkt_len < 1)
-				goto out;
-			pkt_len--;
-			p++;
-		} else {
-			/* This is any other option. So we get the length... */
-			if (pkt_len < 1)
-				goto out;
-			pkt_len--;
-			p++;
-
-			/* ...and then we jump over the data */
-			if (pkt_len < 1 + (*p))
-				goto out;
-			pkt_len -= 1 + (*p);
-			p += 1 + (*p);
-		}
-	}
 out:
+	batadv_hardif_put(primary_if);
+	dev_put(mesh_iface);
+
 	return ret;
 }
 
-bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
+/**
+ * batadv_gw_dhcp_recipient_get() - check if a packet is a DHCP message
+ * @skb: the packet to check
+ * @header_len: a pointer to the batman-adv header size
+ * @chaddr: buffer where the client address will be stored. Valid
+ *  only if the function returns BATADV_DHCP_TO_CLIENT
+ *
+ * This function may re-allocate the data buffer of the skb passed as argument.
+ *
+ * Return:
+ * - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
+ *   while parsing it
+ * - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
+ * - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
+ */
+enum batadv_dhcp_recipient
+batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
+			     u8 *chaddr)
 {
+	enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
 	struct ethhdr *ethhdr;
 	struct iphdr *iphdr;
 	struct ipv6hdr *ipv6hdr;
 	struct udphdr *udphdr;
+	struct vlan_ethhdr *vhdr;
+	int chaddr_offset;
+	__be16 proto;
+	u8 *p;
 
 	/* check for ethernet header */
 	if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
-		return false;
-	ethhdr = (struct ethhdr *)skb->data;
+		return BATADV_DHCP_NO;
+
+	ethhdr = eth_hdr(skb);
+	proto = ethhdr->h_proto;
 	*header_len += ETH_HLEN;
 
 	/* check for initial vlan header */
-	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
+	if (proto == htons(ETH_P_8021Q)) {
 		if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
-			return false;
-		ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
+			return BATADV_DHCP_NO;
+
+		vhdr = vlan_eth_hdr(skb);
+		proto = vhdr->h_vlan_encapsulated_proto;
 		*header_len += VLAN_HLEN;
 	}
 
 	/* check for ip header */
-	switch (ntohs(ethhdr->h_proto)) {
-	case ETH_P_IP:
+	switch (proto) {
+	case htons(ETH_P_IP):
 		if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
-			return false;
+			return BATADV_DHCP_NO;
+
 		iphdr = (struct iphdr *)(skb->data + *header_len);
 		*header_len += iphdr->ihl * 4;
 
 		/* check for udp header */
 		if (iphdr->protocol != IPPROTO_UDP)
-			return false;
+			return BATADV_DHCP_NO;
 
 		break;
-	case ETH_P_IPV6:
+	case htons(ETH_P_IPV6):
 		if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
-			return false;
+			return BATADV_DHCP_NO;
+
 		ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
 		*header_len += sizeof(*ipv6hdr);
 
 		/* check for udp header */
 		if (ipv6hdr->nexthdr != IPPROTO_UDP)
-			return false;
+			return BATADV_DHCP_NO;
 
 		break;
 	default:
-		return false;
+		return BATADV_DHCP_NO;
 	}
 
 	if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
-		return false;
+		return BATADV_DHCP_NO;
+
 	udphdr = (struct udphdr *)(skb->data + *header_len);
 	*header_len += sizeof(*udphdr);
 
 	/* check for bootp port */
-	if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
-	    (ntohs(udphdr->dest) != 67))
-		return false;
+	switch (proto) {
+	case htons(ETH_P_IP):
+		if (udphdr->dest == htons(67))
+			ret = BATADV_DHCP_TO_SERVER;
+		else if (udphdr->source == htons(67))
+			ret = BATADV_DHCP_TO_CLIENT;
+		break;
+	case htons(ETH_P_IPV6):
+		if (udphdr->dest == htons(547))
+			ret = BATADV_DHCP_TO_SERVER;
+		else if (udphdr->source == htons(547))
+			ret = BATADV_DHCP_TO_CLIENT;
+		break;
+	}
+
+	chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
+	/* store the client address if the message is going to a client */
+	if (ret == BATADV_DHCP_TO_CLIENT) {
+		if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN))
+			return BATADV_DHCP_NO;
 
-	if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
-	    (ntohs(udphdr->dest) != 547))
-		return false;
+		/* check if the DHCP packet carries an Ethernet DHCP */
+		p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
+		if (*p != BATADV_DHCP_HTYPE_ETHERNET)
+			return BATADV_DHCP_NO;
 
-	return true;
+		/* check if the DHCP packet carries a valid Ethernet address */
+		p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
+		if (*p != ETH_ALEN)
+			return BATADV_DHCP_NO;
+
+		ether_addr_copy(chaddr, skb->data + chaddr_offset);
+	}
+
+	return ret;
 }
 
+/**
+ * batadv_gw_out_of_range() - check if the dhcp request destination is the best
+ *  gateway
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @skb: the outgoing packet
+ *
+ * Check if the skb is a DHCP request and if it is sent to the current best GW
+ * server. Due to topology changes it may be the case that the GW server
+ * previously selected is not the best one anymore.
+ *
+ * This call might reallocate skb data.
+ * Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
+ *
+ * Return: true if the packet destination is unicast and it is not the best gw,
+ * false otherwise.
+ */
 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
-			    struct sk_buff *skb, struct ethhdr *ethhdr)
+			    struct sk_buff *skb)
 {
-	struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
+	struct batadv_neigh_node *neigh_curr = NULL;
+	struct batadv_neigh_node *neigh_old = NULL;
 	struct batadv_orig_node *orig_dst_node = NULL;
+	struct batadv_gw_node *gw_node = NULL;
 	struct batadv_gw_node *curr_gw = NULL;
-	bool ret, out_of_range = false;
-	unsigned int header_len = 0;
-	uint8_t curr_tq_avg;
+	struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
+	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+	bool out_of_range = false;
+	u8 curr_tq_avg;
+	unsigned short vid;
+
+	vid = batadv_get_vid(skb, 0);
 
-	ret = batadv_gw_is_dhcp_target(skb, &header_len);
-	if (!ret)
+	if (is_multicast_ether_addr(ethhdr->h_dest))
 		goto out;
 
 	orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
-						 ethhdr->h_dest);
+						 ethhdr->h_dest, vid);
 	if (!orig_dst_node)
 		goto out;
 
-	if (!orig_dst_node->gw_flags)
-		goto out;
-
-	ret = batadv_is_type_dhcprequest(skb, header_len);
-	if (!ret)
+	gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
+	if (!gw_node)
 		goto out;
 
-	switch (atomic_read(&bat_priv->gw_mode)) {
+	switch (atomic_read(&bat_priv->gw.mode)) {
 	case BATADV_GW_MODE_SERVER:
 		/* If we are a GW then we are our best GW. We can artificially
 		 * set the tq towards ourself as the maximum value
@@ -685,7 +723,14 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 		if (!neigh_curr)
 			goto out;
 
-		curr_tq_avg = neigh_curr->tq_avg;
+		curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
+						      BATADV_IF_DEFAULT);
+		if (!curr_ifinfo)
+			goto out;
+
+		curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
+		batadv_neigh_ifinfo_put(curr_ifinfo);
+
 		break;
 	case BATADV_GW_MODE_OFF:
 	default:
@@ -696,17 +741,19 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
 	if (!neigh_old)
 		goto out;
 
-	if (curr_tq_avg - neigh_old->tq_avg > BATADV_GW_THRESHOLD)
+	old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
+	if (!old_ifinfo)
+		goto out;
+
+	if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
 		out_of_range = true;
+	batadv_neigh_ifinfo_put(old_ifinfo);
 
 out:
-	if (orig_dst_node)
-		batadv_orig_node_free_ref(orig_dst_node);
-	if (curr_gw)
-		batadv_gw_node_free_ref(curr_gw);
-	if (neigh_old)
-		batadv_neigh_node_free_ref(neigh_old);
-	if (neigh_curr)
-		batadv_neigh_node_free_ref(neigh_curr);
+	batadv_orig_node_put(orig_dst_node);
+	batadv_gw_node_put(curr_gw);
+	batadv_gw_node_put(gw_node);
+	batadv_neigh_node_put(neigh_old);
+	batadv_neigh_node_put(neigh_curr);
 	return out_of_range;
 }