net/batman-adv/hard-interface.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
  *
  * Marek Lindner, Simon Wunderlich
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  * 02110-1301, USA
  *
  */

 #include "main.h"
 #include "hard-interface.h"
 #include "soft-interface.h"
 #include "send.h"
 #include "translation-table.h"
 #include "routing.h"
 #include "bat_sysfs.h"
 #include "originator.h"
 #include "hash.h"

 #include <linux/if_arp.h>


 static int batman_skb_recv(struct sk_buff *skb,
 			   struct net_device *dev,
 			   struct packet_type *ptype,
 			   struct net_device *orig_dev);

 void hardif_free_rcu(struct rcu_head *rcu)
 {
 	struct hard_iface *hard_iface;

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

 struct hard_iface *hardif_get_by_netdev(const struct net_device *net_dev)
 {
 	struct hard_iface *hard_iface;

 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &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 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 (softif_is_valid(net_dev))
 		return 0;

 	/* Device is being bridged */
 	/* if (net_dev->priv_flags & IFF_BRIDGE_PORT)
 		return 0; */

 	return 1;
 }

 static struct hard_iface *hardif_get_active(const struct net_device *soft_iface)
 {
 	struct hard_iface *hard_iface;

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

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

 	hard_iface = NULL;

 out:
 	rcu_read_unlock();
 	return hard_iface;
 }

 static void primary_if_update_addr(struct bat_priv *bat_priv)
 {
 	struct vis_packet *vis_packet;
 	struct hard_iface *primary_if;

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

 	vis_packet = (struct vis_packet *)
 				bat_priv->my_vis_info->skb_packet->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);

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

 static void primary_if_select(struct bat_priv *bat_priv,
 			      struct hard_iface *new_hard_iface)
 {
 	struct hard_iface *curr_hard_iface;
 	struct batman_packet *batman_packet;

 	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 (curr_hard_iface)
 		hardif_free_ref(curr_hard_iface);

 	if (!new_hard_iface)
 		return;

 	batman_packet = (struct batman_packet *)(new_hard_iface->packet_buff);
 	batman_packet->flags = PRIMARIES_FIRST_HOP;
 	batman_packet->ttl = TTL;

 	primary_if_update_addr(bat_priv);
 }

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

 	return false;
 }

 static void update_mac_addresses(struct hard_iface *hard_iface)
 {
 	memcpy(((struct batman_packet *)(hard_iface->packet_buff))->orig,
 	       hard_iface->net_dev->dev_addr, ETH_ALEN);
 	memcpy(((struct batman_packet *)(hard_iface->packet_buff))->prev_sender,
 	       hard_iface->net_dev->dev_addr, ETH_ALEN);
 }

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

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

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

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

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

 int hardif_min_mtu(struct net_device *soft_iface)
 {
 	const struct bat_priv *bat_priv = netdev_priv(soft_iface);
 	const struct 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, &hardif_list, list) {
 		if ((hard_iface->if_status != IF_ACTIVE) &&
 		    (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 			continue;

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

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

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

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

 static void hardif_activate_interface(struct hard_iface *hard_iface)
 {
 	struct bat_priv *bat_priv;
 	struct hard_iface *primary_if = NULL;

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

 	bat_priv = netdev_priv(hard_iface->soft_iface);

 	update_mac_addresses(hard_iface);
 	hard_iface->if_status = 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 = primary_if_get_selected(bat_priv);
 	if (!primary_if)
 		primary_if_select(bat_priv, hard_iface);

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

 	update_min_mtu(hard_iface->soft_iface);

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

 static void hardif_deactivate_interface(struct hard_iface *hard_iface)
 {
 	if ((hard_iface->if_status != IF_ACTIVE) &&
 	    (hard_iface->if_status != IF_TO_BE_ACTIVATED))
 		return;

 	hard_iface->if_status = IF_INACTIVE;

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

 	update_min_mtu(hard_iface->soft_iface);
 }

 int hardif_enable_interface(struct hard_iface *hard_iface,
 			    const char *iface_name)
 {
 	struct bat_priv *bat_priv;
 	struct batman_packet *batman_packet;
 	struct net_device *soft_iface;
 	int ret;

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

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

 	soft_iface = dev_get_by_name(&init_net, iface_name);

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

 	hard_iface->soft_iface = soft_iface;
 	bat_priv = netdev_priv(hard_iface->soft_iface);
 	hard_iface->packet_len = BAT_PACKET_LEN;
 	hard_iface->packet_buff = kmalloc(hard_iface->packet_len, GFP_ATOMIC);

 	if (!hard_iface->packet_buff) {
 		bat_err(hard_iface->soft_iface, "Can't add interface packet "
 			"(%s): out of memory\n", hard_iface->net_dev->name);
 		ret = -ENOMEM;
 		goto err;
 	}

 	batman_packet = (struct batman_packet *)(hard_iface->packet_buff);
 	batman_packet->packet_type = BAT_PACKET;
 	batman_packet->version = COMPAT_VERSION;
 	batman_packet->flags = NO_FLAGS;
 	batman_packet->ttl = 2;
 	batman_packet->tq = TQ_MAX_VALUE;
 	batman_packet->tt_num_changes = 0;
 	batman_packet->ttvn = 0;

 	hard_iface->if_num = bat_priv->num_ifaces;
 	bat_priv->num_ifaces++;
 	hard_iface->if_status = IF_INACTIVE;
 	orig_hash_add_if(hard_iface, bat_priv->num_ifaces);

 	hard_iface->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 	hard_iface->batman_adv_ptype.func = 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->seqno, 1);
 	atomic_set(&hard_iface->frag_seqno, 1);
 	bat_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 + BAT_HEADER_LEN)
 		bat_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 + BAT_HEADER_LEN);

 	if (!atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
 		ETH_DATA_LEN + BAT_HEADER_LEN)
 		bat_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 + BAT_HEADER_LEN);

 	if (hardif_is_iface_up(hard_iface))
 		hardif_activate_interface(hard_iface);
 	else
 		bat_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 */
 	schedule_own_packet(hard_iface);

 out:
 	return 0;

 err:
 	hardif_free_ref(hard_iface);
 	return ret;
 }

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

 	if (hard_iface->if_status == IF_ACTIVE)
 		hardif_deactivate_interface(hard_iface);

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

 	bat_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--;
 	orig_hash_del_if(hard_iface, bat_priv->num_ifaces);

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

 		new_if = hardif_get_active(hard_iface->soft_iface);
 		primary_if_select(bat_priv, new_if);

 		if (new_if)
 			hardif_free_ref(new_if);
 	}

 	kfree(hard_iface->packet_buff);
 	hard_iface->packet_buff = NULL;
 	hard_iface->if_status = IF_NOT_IN_USE;

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

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

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

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

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

 	ASSERT_RTNL();

 	ret = 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) {
 		pr_err("Can't add interface (%s): out of memory\n",
 		       net_dev->name);
 		goto release_dev;
 	}

 	ret = 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 = IF_NOT_IN_USE;
 	INIT_LIST_HEAD(&hard_iface->list);
 	/* extra reference for return */
 	atomic_set(&hard_iface->refcount, 2);

 	check_known_mac_addr(hard_iface->net_dev);
 	list_add_tail_rcu(&hard_iface->list, &hardif_list);

 	return hard_iface;

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

 static void hardif_remove_interface(struct hard_iface *hard_iface)
 {
 	ASSERT_RTNL();

 	/* first deactivate interface */
 	if (hard_iface->if_status != IF_NOT_IN_USE)
 		hardif_disable_interface(hard_iface);

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

 	hard_iface->if_status = IF_TO_BE_REMOVED;
 	sysfs_del_hardif(&hard_iface->hardif_obj);
 	hardif_free_ref(hard_iface);
 }

 void hardif_remove_interfaces(void)
 {
 	struct hard_iface *hard_iface, *hard_iface_tmp;

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

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

 	if (!hard_iface && event == NETDEV_REGISTER)
 		hard_iface = hardif_add_interface(net_dev);

 	if (!hard_iface)
 		goto out;

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

 		hardif_remove_interface(hard_iface);
 		break;
 	case NETDEV_CHANGEMTU:
 		if (hard_iface->soft_iface)
 			update_min_mtu(hard_iface->soft_iface);
 		break;
 	case NETDEV_CHANGEADDR:
 		if (hard_iface->if_status == IF_NOT_IN_USE)
 			goto hardif_put;

 		check_known_mac_addr(hard_iface->net_dev);
 		update_mac_addresses(hard_iface);

 		bat_priv = netdev_priv(hard_iface->soft_iface);
 		primary_if = primary_if_get_selected(bat_priv);
 		if (!primary_if)
 			goto hardif_put;

 		if (hard_iface == primary_if)
 			primary_if_update_addr(bat_priv);
 		break;
 	default:
 		break;
 	}

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

 /* incoming packets with the batman ethertype received on any active hard
  * interface */
 static int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 			   struct packet_type *ptype,
 			   struct net_device *orig_dev)
 {
 	struct bat_priv *bat_priv;
 	struct batman_packet *batman_packet;
 	struct hard_iface *hard_iface;
 	int ret;

 	hard_iface = container_of(ptype, struct hard_iface, batman_adv_ptype);
 	skb = skb_share_check(skb, GFP_ATOMIC);

 	/* skb was released by skb_share_check() */
 	if (!skb)
 		goto err_out;

 	/* packet should hold at least type and version */
 	if (unlikely(!pskb_may_pull(skb, 2)))
 		goto err_free;

 	/* expect a valid ethernet header here. */
 	if (unlikely(skb->mac_len != sizeof(struct ethhdr)
 				|| !skb_mac_header(skb)))
 		goto err_free;

 	if (!hard_iface->soft_iface)
 		goto err_free;

 	bat_priv = netdev_priv(hard_iface->soft_iface);

 	if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
 		goto err_free;

 	/* discard frames on not active interfaces */
 	if (hard_iface->if_status != IF_ACTIVE)
 		goto err_free;

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

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

 	/* all receive handlers return whether they received or reused
 	 * the supplied skb. if not, we have to free the skb. */

 	switch (batman_packet->packet_type) {
 		/* batman originator packet */
 	case BAT_PACKET:
 		ret = recv_bat_packet(skb, hard_iface);
 		break;

 		/* batman icmp packet */
 	case BAT_ICMP:
 		ret = recv_icmp_packet(skb, hard_iface);
 		break;

 		/* unicast packet */
 	case BAT_UNICAST:
 		ret = recv_unicast_packet(skb, hard_iface);
 		break;

 		/* fragmented unicast packet */
 	case BAT_UNICAST_FRAG:
 		ret = recv_ucast_frag_packet(skb, hard_iface);
 		break;

 		/* broadcast packet */
 	case BAT_BCAST:
 		ret = recv_bcast_packet(skb, hard_iface);
 		break;

 		/* vis packet */
 	case BAT_VIS:
 		ret = recv_vis_packet(skb, hard_iface);
 		break;
 		/* Translation table query (request or response) */
 	case BAT_TT_QUERY:
 		ret = recv_tt_query(skb, hard_iface);
 		break;
 		/* Roaming advertisement */
 	case BAT_ROAM_ADV:
 		ret = recv_roam_adv(skb, hard_iface);
 		break;
 	default:
 		ret = NET_RX_DROP;
 	}

 	if (ret == NET_RX_DROP)
 		kfree_skb(skb);

 	/* return NET_RX_SUCCESS in any case as we
 	 * most probably dropped the packet for
 	 * routing-logical reasons. */

 	return NET_RX_SUCCESS;

 err_free:
 	kfree_skb(skb);
 err_out:
 	return NET_RX_DROP;
 }

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

 	if (ifindex == 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 hard_if_notifier = {
 	.notifier_call = hard_if_event,
 };
	/*
	* Copyright (C) 2007-2011 B.A.T.M.A.N. contributors:
	*
	* Marek Lindner, Simon Wunderlich
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General Public
	* License as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	* 02110-1301, USA
	*
	*/

	#include "main.h"
	#include "hard-interface.h"
	#include "soft-interface.h"
	#include "send.h"
	#include "translation-table.h"
	#include "routing.h"
	#include "bat_sysfs.h"
	#include "originator.h"
	#include "hash.h"

	#include <linux/if_arp.h>


	static int batman_skb_recv(struct sk_buff *skb,
	struct net_device *dev,
	struct packet_type *ptype,
	struct net_device *orig_dev);

	void hardif_free_rcu(struct rcu_head *rcu)
	{
	struct hard_iface *hard_iface;

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

	struct hard_iface hardif_get_by_netdev(const struct net_device net_dev)
	{
	struct hard_iface *hard_iface;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &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 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 (softif_is_valid(net_dev))
	return 0;

	/* Device is being bridged */
	/* if (net_dev->priv_flags & IFF_BRIDGE_PORT)
	return 0; */

	return 1;
	}

	static struct hard_iface hardif_get_active(const struct net_device soft_iface)
	{
	struct hard_iface *hard_iface;

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

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

	hard_iface = NULL;

	out:
	rcu_read_unlock();
	return hard_iface;
	}

	static void primary_if_update_addr(struct bat_priv *bat_priv)
	{
	struct vis_packet *vis_packet;
	struct hard_iface *primary_if;

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

	vis_packet = (struct vis_packet *)
	bat_priv->my_vis_info->skb_packet->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);

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

	static void primary_if_select(struct bat_priv *bat_priv,
	struct hard_iface *new_hard_iface)
	{
	struct hard_iface *curr_hard_iface;
	struct batman_packet *batman_packet;

	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 (curr_hard_iface)
	hardif_free_ref(curr_hard_iface);

	if (!new_hard_iface)
	return;

	batman_packet = (struct batman_packet *)(new_hard_iface->packet_buff);
	batman_packet->flags = PRIMARIES_FIRST_HOP;
	batman_packet->ttl = TTL;

	primary_if_update_addr(bat_priv);
	}

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

	return false;
	}

	static void update_mac_addresses(struct hard_iface *hard_iface)
	{
	memcpy(((struct batman_packet *)(hard_iface->packet_buff))->orig,
	hard_iface->net_dev->dev_addr, ETH_ALEN);
	memcpy(((struct batman_packet *)(hard_iface->packet_buff))->prev_sender,
	hard_iface->net_dev->dev_addr, ETH_ALEN);
	}

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

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

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

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

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

	int hardif_min_mtu(struct net_device *soft_iface)
	{
	const struct bat_priv *bat_priv = netdev_priv(soft_iface);
	const struct 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, &hardif_list, list) {
	if ((hard_iface->if_status != IF_ACTIVE) &&
	(hard_iface->if_status != IF_TO_BE_ACTIVATED))
	continue;

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

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

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

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

	static void hardif_activate_interface(struct hard_iface *hard_iface)
	{
	struct bat_priv *bat_priv;
	struct hard_iface *primary_if = NULL;

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

	bat_priv = netdev_priv(hard_iface->soft_iface);

	update_mac_addresses(hard_iface);
	hard_iface->if_status = 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 = primary_if_get_selected(bat_priv);
	if (!primary_if)
	primary_if_select(bat_priv, hard_iface);

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

	update_min_mtu(hard_iface->soft_iface);

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

	static void hardif_deactivate_interface(struct hard_iface *hard_iface)
	{
	if ((hard_iface->if_status != IF_ACTIVE) &&
	(hard_iface->if_status != IF_TO_BE_ACTIVATED))
	return;

	hard_iface->if_status = IF_INACTIVE;

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

	update_min_mtu(hard_iface->soft_iface);
	}

	int hardif_enable_interface(struct hard_iface *hard_iface,
	const char *iface_name)
	{
	struct bat_priv *bat_priv;
	struct batman_packet *batman_packet;
	struct net_device *soft_iface;
	int ret;

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

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

	soft_iface = dev_get_by_name(&init_net, iface_name);

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

	hard_iface->soft_iface = soft_iface;
	bat_priv = netdev_priv(hard_iface->soft_iface);
	hard_iface->packet_len = BAT_PACKET_LEN;
	hard_iface->packet_buff = kmalloc(hard_iface->packet_len, GFP_ATOMIC);

	if (!hard_iface->packet_buff) {
	bat_err(hard_iface->soft_iface, "Can't add interface packet "
	"(%s): out of memory\n", hard_iface->net_dev->name);
	ret = -ENOMEM;
	goto err;
	}

	batman_packet = (struct batman_packet *)(hard_iface->packet_buff);
	batman_packet->packet_type = BAT_PACKET;
	batman_packet->version = COMPAT_VERSION;
	batman_packet->flags = NO_FLAGS;
	batman_packet->ttl = 2;
	batman_packet->tq = TQ_MAX_VALUE;
	batman_packet->tt_num_changes = 0;
	batman_packet->ttvn = 0;

	hard_iface->if_num = bat_priv->num_ifaces;
	bat_priv->num_ifaces++;
	hard_iface->if_status = IF_INACTIVE;
	orig_hash_add_if(hard_iface, bat_priv->num_ifaces);

	hard_iface->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
	hard_iface->batman_adv_ptype.func = 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->seqno, 1);
	atomic_set(&hard_iface->frag_seqno, 1);
	bat_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 + BAT_HEADER_LEN)
	bat_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 + BAT_HEADER_LEN);

	if (!atomic_read(&bat_priv->fragmentation) && hard_iface->net_dev->mtu <
	ETH_DATA_LEN + BAT_HEADER_LEN)
	bat_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 + BAT_HEADER_LEN);

	if (hardif_is_iface_up(hard_iface))
	hardif_activate_interface(hard_iface);
	else
	bat_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 */
	schedule_own_packet(hard_iface);

	out:
	return 0;

	err:
	hardif_free_ref(hard_iface);
	return ret;
	}

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

	if (hard_iface->if_status == IF_ACTIVE)
	hardif_deactivate_interface(hard_iface);

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

	bat_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--;
	orig_hash_del_if(hard_iface, bat_priv->num_ifaces);

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

	new_if = hardif_get_active(hard_iface->soft_iface);
	primary_if_select(bat_priv, new_if);

	if (new_if)
	hardif_free_ref(new_if);
	}

	kfree(hard_iface->packet_buff);
	hard_iface->packet_buff = NULL;
	hard_iface->if_status = IF_NOT_IN_USE;

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

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

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

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

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

	ASSERT_RTNL();

	ret = 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) {
	pr_err("Can't add interface (%s): out of memory\n",
	net_dev->name);
	goto release_dev;
	}

	ret = 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 = IF_NOT_IN_USE;
	INIT_LIST_HEAD(&hard_iface->list);
	/* extra reference for return */
	atomic_set(&hard_iface->refcount, 2);

	check_known_mac_addr(hard_iface->net_dev);
	list_add_tail_rcu(&hard_iface->list, &hardif_list);

	return hard_iface;

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

	static void hardif_remove_interface(struct hard_iface *hard_iface)
	{
	ASSERT_RTNL();

	/* first deactivate interface */
	if (hard_iface->if_status != IF_NOT_IN_USE)
	hardif_disable_interface(hard_iface);

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

	hard_iface->if_status = IF_TO_BE_REMOVED;
	sysfs_del_hardif(&hard_iface->hardif_obj);
	hardif_free_ref(hard_iface);
	}

	void hardif_remove_interfaces(void)
	{
	struct hard_iface hard_iface, hard_iface_tmp;

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

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

	if (!hard_iface && event == NETDEV_REGISTER)
	hard_iface = hardif_add_interface(net_dev);

	if (!hard_iface)
	goto out;

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

	hardif_remove_interface(hard_iface);
	break;
	case NETDEV_CHANGEMTU:
	if (hard_iface->soft_iface)
	update_min_mtu(hard_iface->soft_iface);
	break;
	case NETDEV_CHANGEADDR:
	if (hard_iface->if_status == IF_NOT_IN_USE)
	goto hardif_put;

	check_known_mac_addr(hard_iface->net_dev);
	update_mac_addresses(hard_iface);

	bat_priv = netdev_priv(hard_iface->soft_iface);
	primary_if = primary_if_get_selected(bat_priv);
	if (!primary_if)
	goto hardif_put;

	if (hard_iface == primary_if)
	primary_if_update_addr(bat_priv);
	break;
	default:
	break;
	}

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

	/* incoming packets with the batman ethertype received on any active hard
	* interface */
	static int batman_skb_recv(struct sk_buff skb, struct net_device dev,
	struct packet_type *ptype,
	struct net_device *orig_dev)
	{
	struct bat_priv *bat_priv;
	struct batman_packet *batman_packet;
	struct hard_iface *hard_iface;
	int ret;

	hard_iface = container_of(ptype, struct hard_iface, batman_adv_ptype);
	skb = skb_share_check(skb, GFP_ATOMIC);

	/* skb was released by skb_share_check() */
	if (!skb)
	goto err_out;

	/* packet should hold at least type and version */
	if (unlikely(!pskb_may_pull(skb, 2)))
	goto err_free;

	/* expect a valid ethernet header here. */
	if (unlikely(skb->mac_len != sizeof(struct ethhdr)
	\|\| !skb_mac_header(skb)))
	goto err_free;

	if (!hard_iface->soft_iface)
	goto err_free;

	bat_priv = netdev_priv(hard_iface->soft_iface);

	if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
	goto err_free;

	/* discard frames on not active interfaces */
	if (hard_iface->if_status != IF_ACTIVE)
	goto err_free;

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

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

	/* all receive handlers return whether they received or reused
	* the supplied skb. if not, we have to free the skb. */

	switch (batman_packet->packet_type) {
	/* batman originator packet */
	case BAT_PACKET:
	ret = recv_bat_packet(skb, hard_iface);
	break;

	/* batman icmp packet */
	case BAT_ICMP:
	ret = recv_icmp_packet(skb, hard_iface);
	break;

	/* unicast packet */
	case BAT_UNICAST:
	ret = recv_unicast_packet(skb, hard_iface);
	break;

	/* fragmented unicast packet */
	case BAT_UNICAST_FRAG:
	ret = recv_ucast_frag_packet(skb, hard_iface);
	break;

	/* broadcast packet */
	case BAT_BCAST:
	ret = recv_bcast_packet(skb, hard_iface);
	break;

	/* vis packet */
	case BAT_VIS:
	ret = recv_vis_packet(skb, hard_iface);
	break;
	/* Translation table query (request or response) */
	case BAT_TT_QUERY:
	ret = recv_tt_query(skb, hard_iface);
	break;
	/* Roaming advertisement */
	case BAT_ROAM_ADV:
	ret = recv_roam_adv(skb, hard_iface);
	break;
	default:
	ret = NET_RX_DROP;
	}

	if (ret == NET_RX_DROP)
	kfree_skb(skb);

	/* return NET_RX_SUCCESS in any case as we
	* most probably dropped the packet for
	* routing-logical reasons. */

	return NET_RX_SUCCESS;

	err_free:
	kfree_skb(skb);
	err_out:
	return NET_RX_DROP;
	}

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

	if (ifindex == 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 hard_if_notifier = {
	.notifier_call = hard_if_event,
	};