net/batman-adv/hard-interface.c - kernel/msm-5.4 - Gitiles

 /* Copyright (C) 2007-2012 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 "distributed-arp-table.h"
 #include "hard-interface.h"
 #include "soft-interface.h"
 #include "send.h"
 #include "translation-table.h"
 #include "routing.h"
 #include "sysfs.h"
 #include "originator.h"
 #include "hash.h"
 #include "bridge_loop_avoidance.h"

 #include <linux/if_arp.h>

 void batadv_hardif_free_rcu(struct rcu_head *rcu)
 {
 	struct batadv_hard_iface *hard_iface;

 	hard_iface = container_of(rcu, struct batadv_hard_iface, rcu);
 	dev_put(hard_iface->net_dev);
 	kfree(hard_iface);
 }

 struct batadv_hard_iface *
 batadv_hardif_get_by_netdev(const struct net_device *net_dev)
 {
 	struct batadv_hard_iface *hard_iface;

 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 		if (hard_iface->net_dev == net_dev &&
 		    atomic_inc_not_zero(&hard_iface->refcount))
 			goto out;
 	}

 	hard_iface = NULL;

 out:
 	rcu_read_unlock();
 	return hard_iface;
 }

 static int batadv_is_valid_iface(const struct net_device *net_dev)
 {
 	if (net_dev->flags & IFF_LOOPBACK)
 		return 0;

 	if (net_dev->type != ARPHRD_ETHER)
 		return 0;

 	if (net_dev->addr_len != ETH_ALEN)
 		return 0;

 	/* no batman over batman */
 	if (batadv_softif_is_valid(net_dev))
 		return 0;

 	return 1;
 }

 static struct batadv_hard_iface *
 batadv_hardif_get_active(const struct net_device *soft_iface)
 {
 	struct batadv_hard_iface *hard_iface;

 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 		if (hard_iface->soft_iface != soft_iface)
 			continue;

 		if (hard_iface->if_status == BATADV_IF_ACTIVE &&
 		    atomic_inc_not_zero(&hard_iface->refcount))
 			goto out;
 	}

 	hard_iface = NULL;

 out:
 	rcu_read_unlock();
 	return hard_iface;
 }

 static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
 					  struct batadv_hard_iface *oldif)
 {
 	struct batadv_vis_packet *vis_packet;
 	struct batadv_hard_iface *primary_if;
 	struct sk_buff *skb;

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

 	batadv_dat_init_own_addr(bat_priv, primary_if);

 	skb = bat_priv->vis.my_info->skb_packet;
 	vis_packet = (struct batadv_vis_packet *)skb->data;
 	memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
 	memcpy(vis_packet->sender_orig,
 	       primary_if->net_dev->dev_addr, ETH_ALEN);

 	batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 }

 static void batadv_primary_if_select(struct batadv_priv *bat_priv,
 				     struct batadv_hard_iface *new_hard_iface)
 {
 	struct batadv_hard_iface *curr_hard_iface;

 	ASSERT_RTNL();

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

 	curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
 	rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);

 	if (!new_hard_iface)
 		goto out;

 	bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
 	batadv_primary_if_update_addr(bat_priv, curr_hard_iface);

 out:
 	if (curr_hard_iface)
 		batadv_hardif_free_ref(curr_hard_iface);
 }

 static bool
 batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
 {
 	if (hard_iface->net_dev->flags & IFF_UP)
 		return true;

 	return false;
 }

 static void batadv_check_known_mac_addr(const struct net_device *net_dev)
 {
 	const struct batadv_hard_iface *hard_iface;

 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 		if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 		    (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 			continue;

 		if (hard_iface->net_dev == net_dev)
 			continue;

 		if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
 					net_dev->dev_addr))
 			continue;

 		pr_warn("The newly added mac address (%pM) already exists on: %s\n",
 			net_dev->dev_addr, hard_iface->net_dev->name);
 		pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
 	}
 	rcu_read_unlock();
 }

 int batadv_hardif_min_mtu(struct net_device *soft_iface)
 {
 	const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
 	const struct batadv_hard_iface *hard_iface;
 	/* allow big frames if all devices are capable to do so
 	 * (have MTU > 1500 + BAT_HEADER_LEN)
 	 */
 	int min_mtu = ETH_DATA_LEN;

 	if (atomic_read(&bat_priv->fragmentation))
 		goto out;

 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 		if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 		    (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 			continue;

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

 		min_mtu = min_t(int,
 				hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
 				min_mtu);
 	}
 	rcu_read_unlock();
 out:
 	return min_mtu;
 }

 /* adjusts the MTU if a new interface with a smaller MTU appeared. */
 void batadv_update_min_mtu(struct net_device *soft_iface)
 {
 	int min_mtu;

 	min_mtu = batadv_hardif_min_mtu(soft_iface);
 	if (soft_iface->mtu != min_mtu)
 		soft_iface->mtu = min_mtu;
 }

 static void
 batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_priv *bat_priv;
 	struct batadv_hard_iface *primary_if = NULL;

 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
 		goto out;

 	bat_priv = netdev_priv(hard_iface->soft_iface);

 	bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
 	hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;

 	/* the first active interface becomes our primary interface or
 	 * the next active interface after the old primary interface was removed
 	 */
 	primary_if = batadv_primary_if_get_selected(bat_priv);
 	if (!primary_if)
 		batadv_primary_if_select(bat_priv, hard_iface);

 	batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
 		    hard_iface->net_dev->name);

 	batadv_update_min_mtu(hard_iface->soft_iface);

 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 }

 static void
 batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
 {
 	if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
 	    (hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
 		return;

 	hard_iface->if_status = BATADV_IF_INACTIVE;

 	batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
 		    hard_iface->net_dev->name);

 	batadv_update_min_mtu(hard_iface->soft_iface);
 }

 int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 				   const char *iface_name)
 {
 	struct batadv_priv *bat_priv;
 	struct net_device *soft_iface;
 	__be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
 	int ret;

 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 		goto out;

 	if (!atomic_inc_not_zero(&hard_iface->refcount))
 		goto out;

 	/* hard-interface is part of a bridge */
 	if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
 		pr_err("You are about to enable batman-adv on '%s' which already is part of a bridge. Unless you know exactly what you are doing this is probably wrong and won't work the way you think it would.\n",
 		       hard_iface->net_dev->name);

 	soft_iface = dev_get_by_name(&init_net, iface_name);

 	if (!soft_iface) {
 		soft_iface = batadv_softif_create(iface_name);

 		if (!soft_iface) {
 			ret = -ENOMEM;
 			goto err;
 		}

 		/* dev_get_by_name() increases the reference counter for us */
 		dev_hold(soft_iface);
 	}

 	if (!batadv_softif_is_valid(soft_iface)) {
 		pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
 		       soft_iface->name);
 		ret = -EINVAL;
 		goto err_dev;
 	}

 	hard_iface->soft_iface = soft_iface;
 	bat_priv = netdev_priv(hard_iface->soft_iface);

 	ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
 	if (ret < 0)
 		goto err_dev;

 	hard_iface->if_num = bat_priv->num_ifaces;
 	bat_priv->num_ifaces++;
 	hard_iface->if_status = BATADV_IF_INACTIVE;
 	ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
 	if (ret < 0) {
 		bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 		bat_priv->num_ifaces--;
 		hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 		goto err_dev;
 	}

 	hard_iface->batman_adv_ptype.type = ethertype;
 	hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
 	hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
 	dev_add_pack(&hard_iface->batman_adv_ptype);

 	atomic_set(&hard_iface->frag_seqno, 1);
 	batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
 		    hard_iface->net_dev->name);

 	if (atomic_read(&bat_priv->fragmentation) &&
 	    hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
 		batadv_info(hard_iface->soft_iface,
 			    "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %zi would solve the problem.\n",
 			    hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 			    ETH_DATA_LEN + BATADV_HEADER_LEN);

 	if (!atomic_read(&bat_priv->fragmentation) &&
 	    hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
 		batadv_info(hard_iface->soft_iface,
 			    "The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %zi.\n",
 			    hard_iface->net_dev->name, hard_iface->net_dev->mtu,
 			    ETH_DATA_LEN + BATADV_HEADER_LEN);

 	if (batadv_hardif_is_iface_up(hard_iface))
 		batadv_hardif_activate_interface(hard_iface);
 	else
 		batadv_err(hard_iface->soft_iface,
 			   "Not using interface %s (retrying later): interface not active\n",
 			   hard_iface->net_dev->name);

 	/* begin scheduling originator messages on that interface */
 	batadv_schedule_bat_ogm(hard_iface);

 out:
 	return 0;

 err_dev:
 	dev_put(soft_iface);
 err:
 	batadv_hardif_free_ref(hard_iface);
 	return ret;
 }

 void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 	struct batadv_hard_iface *primary_if = NULL;

 	if (hard_iface->if_status == BATADV_IF_ACTIVE)
 		batadv_hardif_deactivate_interface(hard_iface);

 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
 		goto out;

 	batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
 		    hard_iface->net_dev->name);
 	dev_remove_pack(&hard_iface->batman_adv_ptype);

 	bat_priv->num_ifaces--;
 	batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);

 	primary_if = batadv_primary_if_get_selected(bat_priv);
 	if (hard_iface == primary_if) {
 		struct batadv_hard_iface *new_if;

 		new_if = batadv_hardif_get_active(hard_iface->soft_iface);
 		batadv_primary_if_select(bat_priv, new_if);

 		if (new_if)
 			batadv_hardif_free_ref(new_if);
 	}

 	bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;

 	/* delete all references to this hard_iface */
 	batadv_purge_orig_ref(bat_priv);
 	batadv_purge_outstanding_packets(bat_priv, hard_iface);
 	dev_put(hard_iface->soft_iface);

 	/* nobody uses this interface anymore */
 	if (!bat_priv->num_ifaces)
 		batadv_softif_destroy(hard_iface->soft_iface);

 	hard_iface->soft_iface = NULL;
 	batadv_hardif_free_ref(hard_iface);

 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 }

 static struct batadv_hard_iface *
 batadv_hardif_add_interface(struct net_device *net_dev)
 {
 	struct batadv_hard_iface *hard_iface;
 	int ret;

 	ASSERT_RTNL();

 	ret = batadv_is_valid_iface(net_dev);
 	if (ret != 1)
 		goto out;

 	dev_hold(net_dev);

 	hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
 	if (!hard_iface)
 		goto release_dev;

 	ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
 	if (ret)
 		goto free_if;

 	hard_iface->if_num = -1;
 	hard_iface->net_dev = net_dev;
 	hard_iface->soft_iface = NULL;
 	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
 	INIT_LIST_HEAD(&hard_iface->list);
 	/* extra reference for return */
 	atomic_set(&hard_iface->refcount, 2);

 	batadv_check_known_mac_addr(hard_iface->net_dev);
 	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);

 	/* This can't be called via a bat_priv callback because
 	 * we have no bat_priv yet.
 	 */
 	atomic_set(&hard_iface->bat_iv.ogm_seqno, 1);
 	hard_iface->bat_iv.ogm_buff = NULL;

 	return hard_iface;

 free_if:
 	kfree(hard_iface);
 release_dev:
 	dev_put(net_dev);
 out:
 	return NULL;
 }

 static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
 {
 	ASSERT_RTNL();

 	/* first deactivate interface */
 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 		batadv_hardif_disable_interface(hard_iface);

 	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
 		return;

 	hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
 	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
 	batadv_hardif_free_ref(hard_iface);
 }

 void batadv_hardif_remove_interfaces(void)
 {
 	struct batadv_hard_iface *hard_iface, *hard_iface_tmp;

 	rtnl_lock();
 	list_for_each_entry_safe(hard_iface, hard_iface_tmp,
 				 &batadv_hardif_list, list) {
 		list_del_rcu(&hard_iface->list);
 		batadv_hardif_remove_interface(hard_iface);
 	}
 	rtnl_unlock();
 }

 static int batadv_hard_if_event(struct notifier_block *this,
 				unsigned long event, void *ptr)
 {
 	struct net_device *net_dev = ptr;
 	struct batadv_hard_iface *hard_iface;
 	struct batadv_hard_iface *primary_if = NULL;
 	struct batadv_priv *bat_priv;

 	hard_iface = batadv_hardif_get_by_netdev(net_dev);
 	if (!hard_iface && event == NETDEV_REGISTER)
 		hard_iface = batadv_hardif_add_interface(net_dev);

 	if (!hard_iface)
 		goto out;

 	switch (event) {
 	case NETDEV_UP:
 		batadv_hardif_activate_interface(hard_iface);
 		break;
 	case NETDEV_GOING_DOWN:
 	case NETDEV_DOWN:
 		batadv_hardif_deactivate_interface(hard_iface);
 		break;
 	case NETDEV_UNREGISTER:
 		list_del_rcu(&hard_iface->list);

 		batadv_hardif_remove_interface(hard_iface);
 		break;
 	case NETDEV_CHANGEMTU:
 		if (hard_iface->soft_iface)
 			batadv_update_min_mtu(hard_iface->soft_iface);
 		break;
 	case NETDEV_CHANGEADDR:
 		if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
 			goto hardif_put;

 		batadv_check_known_mac_addr(hard_iface->net_dev);

 		bat_priv = netdev_priv(hard_iface->soft_iface);
 		bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);

 		primary_if = batadv_primary_if_get_selected(bat_priv);
 		if (!primary_if)
 			goto hardif_put;

 		if (hard_iface == primary_if)
 			batadv_primary_if_update_addr(bat_priv, NULL);
 		break;
 	default:
 		break;
 	}

 hardif_put:
 	batadv_hardif_free_ref(hard_iface);
 out:
 	if (primary_if)
 		batadv_hardif_free_ref(primary_if);
 	return NOTIFY_DONE;
 }

 /* This function returns true if the interface represented by ifindex is a
  * 802.11 wireless device
  */
 bool batadv_is_wifi_iface(int ifindex)
 {
 	struct net_device *net_device = NULL;
 	bool ret = false;

 	if (ifindex == BATADV_NULL_IFINDEX)
 		goto out;

 	net_device = dev_get_by_index(&init_net, ifindex);
 	if (!net_device)
 		goto out;

 #ifdef CONFIG_WIRELESS_EXT
 	/* pre-cfg80211 drivers have to implement WEXT, so it is possible to
 	 * check for wireless_handlers != NULL
 	 */
 	if (net_device->wireless_handlers)
 		ret = true;
 	else
 #endif
 		/* cfg80211 drivers have to set ieee80211_ptr */
 		if (net_device->ieee80211_ptr)
 			ret = true;
 out:
 	if (net_device)
 		dev_put(net_device);
 	return ret;
 }

 struct notifier_block batadv_hard_if_notifier = {
 	.notifier_call = batadv_hard_if_event,
 };
	/* Copyright (C) 2007-2012 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 "distributed-arp-table.h"
	#include "hard-interface.h"
	#include "soft-interface.h"
	#include "send.h"
	#include "translation-table.h"
	#include "routing.h"
	#include "sysfs.h"
	#include "originator.h"
	#include "hash.h"
	#include "bridge_loop_avoidance.h"

	#include <linux/if_arp.h>

	void batadv_hardif_free_rcu(struct rcu_head *rcu)
	{
	struct batadv_hard_iface *hard_iface;

	hard_iface = container_of(rcu, struct batadv_hard_iface, rcu);
	dev_put(hard_iface->net_dev);
	kfree(hard_iface);
	}

	struct batadv_hard_iface *
	batadv_hardif_get_by_netdev(const struct net_device *net_dev)
	{
	struct batadv_hard_iface *hard_iface;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
	if (hard_iface->net_dev == net_dev &&
	atomic_inc_not_zero(&hard_iface->refcount))
	goto out;
	}

	hard_iface = NULL;

	out:
	rcu_read_unlock();
	return hard_iface;
	}

	static int batadv_is_valid_iface(const struct net_device *net_dev)
	{
	if (net_dev->flags & IFF_LOOPBACK)
	return 0;

	if (net_dev->type != ARPHRD_ETHER)
	return 0;

	if (net_dev->addr_len != ETH_ALEN)
	return 0;

	/* no batman over batman */
	if (batadv_softif_is_valid(net_dev))
	return 0;

	return 1;
	}

	static struct batadv_hard_iface *
	batadv_hardif_get_active(const struct net_device *soft_iface)
	{
	struct batadv_hard_iface *hard_iface;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
	if (hard_iface->soft_iface != soft_iface)
	continue;

	if (hard_iface->if_status == BATADV_IF_ACTIVE &&
	atomic_inc_not_zero(&hard_iface->refcount))
	goto out;
	}

	hard_iface = NULL;

	out:
	rcu_read_unlock();
	return hard_iface;
	}

	static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
	struct batadv_hard_iface *oldif)
	{
	struct batadv_vis_packet *vis_packet;
	struct batadv_hard_iface *primary_if;
	struct sk_buff *skb;

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

	batadv_dat_init_own_addr(bat_priv, primary_if);

	skb = bat_priv->vis.my_info->skb_packet;
	vis_packet = (struct batadv_vis_packet *)skb->data;
	memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(vis_packet->sender_orig,
	primary_if->net_dev->dev_addr, ETH_ALEN);

	batadv_bla_update_orig_address(bat_priv, primary_if, oldif);
	out:
	if (primary_if)
	batadv_hardif_free_ref(primary_if);
	}

	static void batadv_primary_if_select(struct batadv_priv *bat_priv,
	struct batadv_hard_iface *new_hard_iface)
	{
	struct batadv_hard_iface *curr_hard_iface;

	ASSERT_RTNL();

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

	curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
	rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);

	if (!new_hard_iface)
	goto out;

	bat_priv->bat_algo_ops->bat_primary_iface_set(new_hard_iface);
	batadv_primary_if_update_addr(bat_priv, curr_hard_iface);

	out:
	if (curr_hard_iface)
	batadv_hardif_free_ref(curr_hard_iface);
	}

	static bool
	batadv_hardif_is_iface_up(const struct batadv_hard_iface *hard_iface)
	{
	if (hard_iface->net_dev->flags & IFF_UP)
	return true;

	return false;
	}

	static void batadv_check_known_mac_addr(const struct net_device *net_dev)
	{
	const struct batadv_hard_iface *hard_iface;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
	if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
	(hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
	continue;

	if (hard_iface->net_dev == net_dev)
	continue;

	if (!batadv_compare_eth(hard_iface->net_dev->dev_addr,
	net_dev->dev_addr))
	continue;

	pr_warn("The newly added mac address (%pM) already exists on: %s\n",
	net_dev->dev_addr, hard_iface->net_dev->name);
	pr_warn("It is strongly recommended to keep mac addresses unique to avoid problems!\n");
	}
	rcu_read_unlock();
	}

	int batadv_hardif_min_mtu(struct net_device *soft_iface)
	{
	const struct batadv_priv *bat_priv = netdev_priv(soft_iface);
	const struct batadv_hard_iface *hard_iface;
	/* allow big frames if all devices are capable to do so
	* (have MTU > 1500 + BAT_HEADER_LEN)
	*/
	int min_mtu = ETH_DATA_LEN;

	if (atomic_read(&bat_priv->fragmentation))
	goto out;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
	if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
	(hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
	continue;

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

	min_mtu = min_t(int,
	hard_iface->net_dev->mtu - BATADV_HEADER_LEN,
	min_mtu);
	}
	rcu_read_unlock();
	out:
	return min_mtu;
	}

	/* adjusts the MTU if a new interface with a smaller MTU appeared. */
	void batadv_update_min_mtu(struct net_device *soft_iface)
	{
	int min_mtu;

	min_mtu = batadv_hardif_min_mtu(soft_iface);
	if (soft_iface->mtu != min_mtu)
	soft_iface->mtu = min_mtu;
	}

	static void
	batadv_hardif_activate_interface(struct batadv_hard_iface *hard_iface)
	{
	struct batadv_priv *bat_priv;
	struct batadv_hard_iface *primary_if = NULL;

	if (hard_iface->if_status != BATADV_IF_INACTIVE)
	goto out;

	bat_priv = netdev_priv(hard_iface->soft_iface);

	bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);
	hard_iface->if_status = BATADV_IF_TO_BE_ACTIVATED;

	/* the first active interface becomes our primary interface or
	* the next active interface after the old primary interface was removed
	*/
	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
	batadv_primary_if_select(bat_priv, hard_iface);

	batadv_info(hard_iface->soft_iface, "Interface activated: %s\n",
	hard_iface->net_dev->name);

	batadv_update_min_mtu(hard_iface->soft_iface);

	out:
	if (primary_if)
	batadv_hardif_free_ref(primary_if);
	}

	static void
	batadv_hardif_deactivate_interface(struct batadv_hard_iface *hard_iface)
	{
	if ((hard_iface->if_status != BATADV_IF_ACTIVE) &&
	(hard_iface->if_status != BATADV_IF_TO_BE_ACTIVATED))
	return;

	hard_iface->if_status = BATADV_IF_INACTIVE;

	batadv_info(hard_iface->soft_iface, "Interface deactivated: %s\n",
	hard_iface->net_dev->name);

	batadv_update_min_mtu(hard_iface->soft_iface);
	}

	int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
	const char *iface_name)
	{
	struct batadv_priv *bat_priv;
	struct net_device *soft_iface;
	__be16 ethertype = __constant_htons(BATADV_ETH_P_BATMAN);
	int ret;

	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
	goto out;

	if (!atomic_inc_not_zero(&hard_iface->refcount))
	goto out;

	/* hard-interface is part of a bridge */
	if (hard_iface->net_dev->priv_flags & IFF_BRIDGE_PORT)
	pr_err("You are about to enable batman-adv on '%s' which already is part of a bridge. Unless you know exactly what you are doing this is probably wrong and won't work the way you think it would.\n",
	hard_iface->net_dev->name);

	soft_iface = dev_get_by_name(&init_net, iface_name);

	if (!soft_iface) {
	soft_iface = batadv_softif_create(iface_name);

	if (!soft_iface) {
	ret = -ENOMEM;
	goto err;
	}

	/* dev_get_by_name() increases the reference counter for us */
	dev_hold(soft_iface);
	}

	if (!batadv_softif_is_valid(soft_iface)) {
	pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
	soft_iface->name);
	ret = -EINVAL;
	goto err_dev;
	}

	hard_iface->soft_iface = soft_iface;
	bat_priv = netdev_priv(hard_iface->soft_iface);

	ret = bat_priv->bat_algo_ops->bat_iface_enable(hard_iface);
	if (ret < 0)
	goto err_dev;

	hard_iface->if_num = bat_priv->num_ifaces;
	bat_priv->num_ifaces++;
	hard_iface->if_status = BATADV_IF_INACTIVE;
	ret = batadv_orig_hash_add_if(hard_iface, bat_priv->num_ifaces);
	if (ret < 0) {
	bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
	bat_priv->num_ifaces--;
	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
	goto err_dev;
	}

	hard_iface->batman_adv_ptype.type = ethertype;
	hard_iface->batman_adv_ptype.func = batadv_batman_skb_recv;
	hard_iface->batman_adv_ptype.dev = hard_iface->net_dev;
	dev_add_pack(&hard_iface->batman_adv_ptype);

	atomic_set(&hard_iface->frag_seqno, 1);
	batadv_info(hard_iface->soft_iface, "Adding interface: %s\n",
	hard_iface->net_dev->name);

	if (atomic_read(&bat_priv->fragmentation) &&
	hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
	batadv_info(hard_iface->soft_iface,
	"The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to %zi would solve the problem.\n",
	hard_iface->net_dev->name, hard_iface->net_dev->mtu,
	ETH_DATA_LEN + BATADV_HEADER_LEN);

	if (!atomic_read(&bat_priv->fragmentation) &&
	hard_iface->net_dev->mtu < ETH_DATA_LEN + BATADV_HEADER_LEN)
	batadv_info(hard_iface->soft_iface,
	"The MTU of interface %s is too small (%i) to handle the transport of batman-adv packets. If you experience problems getting traffic through try increasing the MTU to %zi.\n",
	hard_iface->net_dev->name, hard_iface->net_dev->mtu,
	ETH_DATA_LEN + BATADV_HEADER_LEN);

	if (batadv_hardif_is_iface_up(hard_iface))
	batadv_hardif_activate_interface(hard_iface);
	else
	batadv_err(hard_iface->soft_iface,
	"Not using interface %s (retrying later): interface not active\n",
	hard_iface->net_dev->name);

	/* begin scheduling originator messages on that interface */
	batadv_schedule_bat_ogm(hard_iface);

	out:
	return 0;

	err_dev:
	dev_put(soft_iface);
	err:
	batadv_hardif_free_ref(hard_iface);
	return ret;
	}

	void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface)
	{
	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
	struct batadv_hard_iface *primary_if = NULL;

	if (hard_iface->if_status == BATADV_IF_ACTIVE)
	batadv_hardif_deactivate_interface(hard_iface);

	if (hard_iface->if_status != BATADV_IF_INACTIVE)
	goto out;

	batadv_info(hard_iface->soft_iface, "Removing interface: %s\n",
	hard_iface->net_dev->name);
	dev_remove_pack(&hard_iface->batman_adv_ptype);

	bat_priv->num_ifaces--;
	batadv_orig_hash_del_if(hard_iface, bat_priv->num_ifaces);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (hard_iface == primary_if) {
	struct batadv_hard_iface *new_if;

	new_if = batadv_hardif_get_active(hard_iface->soft_iface);
	batadv_primary_if_select(bat_priv, new_if);

	if (new_if)
	batadv_hardif_free_ref(new_if);
	}

	bat_priv->bat_algo_ops->bat_iface_disable(hard_iface);
	hard_iface->if_status = BATADV_IF_NOT_IN_USE;

	/* delete all references to this hard_iface */
	batadv_purge_orig_ref(bat_priv);
	batadv_purge_outstanding_packets(bat_priv, hard_iface);
	dev_put(hard_iface->soft_iface);

	/* nobody uses this interface anymore */
	if (!bat_priv->num_ifaces)
	batadv_softif_destroy(hard_iface->soft_iface);

	hard_iface->soft_iface = NULL;
	batadv_hardif_free_ref(hard_iface);

	out:
	if (primary_if)
	batadv_hardif_free_ref(primary_if);
	}

	static struct batadv_hard_iface *
	batadv_hardif_add_interface(struct net_device *net_dev)
	{
	struct batadv_hard_iface *hard_iface;
	int ret;

	ASSERT_RTNL();

	ret = batadv_is_valid_iface(net_dev);
	if (ret != 1)
	goto out;

	dev_hold(net_dev);

	hard_iface = kmalloc(sizeof(*hard_iface), GFP_ATOMIC);
	if (!hard_iface)
	goto release_dev;

	ret = batadv_sysfs_add_hardif(&hard_iface->hardif_obj, net_dev);
	if (ret)
	goto free_if;

	hard_iface->if_num = -1;
	hard_iface->net_dev = net_dev;
	hard_iface->soft_iface = NULL;
	hard_iface->if_status = BATADV_IF_NOT_IN_USE;
	INIT_LIST_HEAD(&hard_iface->list);
	/* extra reference for return */
	atomic_set(&hard_iface->refcount, 2);

	batadv_check_known_mac_addr(hard_iface->net_dev);
	list_add_tail_rcu(&hard_iface->list, &batadv_hardif_list);

	/* This can't be called via a bat_priv callback because
	* we have no bat_priv yet.
	*/
	atomic_set(&hard_iface->bat_iv.ogm_seqno, 1);
	hard_iface->bat_iv.ogm_buff = NULL;

	return hard_iface;

	free_if:
	kfree(hard_iface);
	release_dev:
	dev_put(net_dev);
	out:
	return NULL;
	}

	static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
	{
	ASSERT_RTNL();

	/* first deactivate interface */
	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
	batadv_hardif_disable_interface(hard_iface);

	if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
	return;

	hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
	batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
	batadv_hardif_free_ref(hard_iface);
	}

	void batadv_hardif_remove_interfaces(void)
	{
	struct batadv_hard_iface hard_iface, hard_iface_tmp;

	rtnl_lock();
	list_for_each_entry_safe(hard_iface, hard_iface_tmp,
	&batadv_hardif_list, list) {
	list_del_rcu(&hard_iface->list);
	batadv_hardif_remove_interface(hard_iface);
	}
	rtnl_unlock();
	}

	static int batadv_hard_if_event(struct notifier_block *this,
	unsigned long event, void *ptr)
	{
	struct net_device *net_dev = ptr;
	struct batadv_hard_iface *hard_iface;
	struct batadv_hard_iface *primary_if = NULL;
	struct batadv_priv *bat_priv;

	hard_iface = batadv_hardif_get_by_netdev(net_dev);
	if (!hard_iface && event == NETDEV_REGISTER)
	hard_iface = batadv_hardif_add_interface(net_dev);

	if (!hard_iface)
	goto out;

	switch (event) {
	case NETDEV_UP:
	batadv_hardif_activate_interface(hard_iface);
	break;
	case NETDEV_GOING_DOWN:
	case NETDEV_DOWN:
	batadv_hardif_deactivate_interface(hard_iface);
	break;
	case NETDEV_UNREGISTER:
	list_del_rcu(&hard_iface->list);

	batadv_hardif_remove_interface(hard_iface);
	break;
	case NETDEV_CHANGEMTU:
	if (hard_iface->soft_iface)
	batadv_update_min_mtu(hard_iface->soft_iface);
	break;
	case NETDEV_CHANGEADDR:
	if (hard_iface->if_status == BATADV_IF_NOT_IN_USE)
	goto hardif_put;

	batadv_check_known_mac_addr(hard_iface->net_dev);

	bat_priv = netdev_priv(hard_iface->soft_iface);
	bat_priv->bat_algo_ops->bat_iface_update_mac(hard_iface);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
	goto hardif_put;

	if (hard_iface == primary_if)
	batadv_primary_if_update_addr(bat_priv, NULL);
	break;
	default:
	break;
	}

	hardif_put:
	batadv_hardif_free_ref(hard_iface);
	out:
	if (primary_if)
	batadv_hardif_free_ref(primary_if);
	return NOTIFY_DONE;
	}

	/* This function returns true if the interface represented by ifindex is a
	* 802.11 wireless device
	*/
	bool batadv_is_wifi_iface(int ifindex)
	{
	struct net_device *net_device = NULL;
	bool ret = false;

	if (ifindex == BATADV_NULL_IFINDEX)
	goto out;

	net_device = dev_get_by_index(&init_net, ifindex);
	if (!net_device)
	goto out;

	#ifdef CONFIG_WIRELESS_EXT
	/* pre-cfg80211 drivers have to implement WEXT, so it is possible to
	* check for wireless_handlers != NULL
	*/
	if (net_device->wireless_handlers)
	ret = true;
	else
	#endif
	/* cfg80211 drivers have to set ieee80211_ptr */
	if (net_device->ieee80211_ptr)
	ret = true;
	out:
	if (net_device)
	dev_put(net_device);
	return ret;
	}

	struct notifier_block batadv_hard_if_notifier = {
	.notifier_call = batadv_hard_if_event,
	};