linux/drivers/staging/batman-adv/hard-interface.c - nest-guard/1.0/linux - Git at Google

 /*
  * Copyright (C) 2007-2010 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>

 #define MIN(x, y) ((x) < (y) ? (x) : (y))

 /* protect update critical side of if_list - but not the content */
 static DEFINE_SPINLOCK(if_list_lock);

 struct batman_if *get_batman_if_by_netdev(struct net_device *net_dev)
 {
 	struct batman_if *batman_if;

 	rcu_read_lock();
 	list_for_each_entry_rcu(batman_if, &if_list, list) {
 		if (batman_if->net_dev == net_dev)
 			goto out;
 	}

 	batman_if = NULL;

 out:
 	if (batman_if)
 		hardif_hold(batman_if);

 	rcu_read_unlock();
 	return batman_if;
 }

 static int is_valid_iface(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 */
 #ifdef HAVE_NET_DEVICE_OPS
 	if (net_dev->netdev_ops->ndo_start_xmit == interface_tx)
 		return 0;
 #else
 	if (net_dev->hard_start_xmit == interface_tx)
 		return 0;
 #endif

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

 	return 1;
 }

 static struct batman_if *get_active_batman_if(struct net_device *soft_iface)
 {
 	struct batman_if *batman_if;

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

 		if (batman_if->if_status == IF_ACTIVE)
 			goto out;
 	}

 	batman_if = NULL;

 out:
 	if (batman_if)
 		hardif_hold(batman_if);

 	rcu_read_unlock();
 	return batman_if;
 }

 static void update_primary_addr(struct bat_priv *bat_priv)
 {
 	struct vis_packet *vis_packet;

 	vis_packet = (struct vis_packet *)
 				bat_priv->my_vis_info->skb_packet->data;
 	memcpy(vis_packet->vis_orig,
 	       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 	memcpy(vis_packet->sender_orig,
 	       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 }

 static void set_primary_if(struct bat_priv *bat_priv,
 			   struct batman_if *batman_if)
 {
 	struct batman_packet *batman_packet;
 	struct batman_if *old_if;

 	if (batman_if)
 		hardif_hold(batman_if);

 	old_if = bat_priv->primary_if;
 	bat_priv->primary_if = batman_if;

 	if (old_if)
 		hardif_put(old_if);

 	if (!bat_priv->primary_if)
 		return;

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

 	update_primary_addr(bat_priv);

 	/***
 	 * hacky trick to make sure that we send the HNA information via
 	 * our new primary interface
 	 */
 	atomic_set(&bat_priv->hna_local_changed, 1);
 }

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

 	return false;
 }

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

 static void check_known_mac_addr(struct net_device *net_dev)
 {
 	struct batman_if *batman_if;

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

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

 		if (!compare_orig(batman_if->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,
 			   batman_if->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)
 {
 	struct bat_priv *bat_priv = netdev_priv(soft_iface);
 	struct batman_if *batman_if;
 	/* 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->frag_enabled))
 		goto out;

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

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

 		min_mtu = MIN(batman_if->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 batman_if *batman_if)
 {
 	struct bat_priv *bat_priv;

 	if (batman_if->if_status != IF_INACTIVE)
 		return;

 	bat_priv = netdev_priv(batman_if->soft_iface);

 	update_mac_addresses(batman_if);
 	batman_if->if_status = IF_TO_BE_ACTIVATED;

 	/**
 	 * the first active interface becomes our primary interface or
 	 * the next active interface after the old primay interface was removed
 	 */
 	if (!bat_priv->primary_if)
 		set_primary_if(bat_priv, batman_if);

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

 	update_min_mtu(batman_if->soft_iface);
 	return;
 }

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

 	batman_if->if_status = IF_INACTIVE;

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

 	update_min_mtu(batman_if->soft_iface);
 }

 int hardif_enable_interface(struct batman_if *batman_if, char *iface_name)
 {
 	struct bat_priv *bat_priv;
 	struct batman_packet *batman_packet;

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

 	batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);

 	if (!batman_if->soft_iface) {
 		batman_if->soft_iface = softif_create(iface_name);

 		if (!batman_if->soft_iface)
 			goto err;

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

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

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

 	batman_packet = (struct batman_packet *)(batman_if->packet_buff);
 	batman_packet->packet_type = BAT_PACKET;
 	batman_packet->version = COMPAT_VERSION;
 	batman_packet->flags = 0;
 	batman_packet->ttl = 2;
 	batman_packet->tq = TQ_MAX_VALUE;
 	batman_packet->num_hna = 0;

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

 	batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
 	batman_if->batman_adv_ptype.func = batman_skb_recv;
 	batman_if->batman_adv_ptype.dev = batman_if->net_dev;
 	hardif_hold(batman_if);
 	dev_add_pack(&batman_if->batman_adv_ptype);

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

 	if (atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu <
 		ETH_DATA_LEN + BAT_HEADER_LEN)
 		bat_info(batman_if->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",
 			batman_if->net_dev->name, batman_if->net_dev->mtu,
 			ETH_DATA_LEN + BAT_HEADER_LEN);

 	if (!atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu <
 		ETH_DATA_LEN + BAT_HEADER_LEN)
 		bat_info(batman_if->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",
 			batman_if->net_dev->name, batman_if->net_dev->mtu,
 			ETH_DATA_LEN + BAT_HEADER_LEN);

 	if (hardif_is_iface_up(batman_if))
 		hardif_activate_interface(batman_if);
 	else
 		bat_err(batman_if->soft_iface, "Not using interface %s "
 			"(retrying later): interface not active\n",
 			batman_if->net_dev->name);

 	/* begin scheduling originator messages on that interface */
 	schedule_own_packet(batman_if);

 out:
 	return 0;

 err:
 	return -ENOMEM;
 }

 void hardif_disable_interface(struct batman_if *batman_if)
 {
 	struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);

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

 	if (batman_if->if_status != IF_INACTIVE)
 		return;

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

 	bat_priv->num_ifaces--;
 	orig_hash_del_if(batman_if, bat_priv->num_ifaces);

 	if (batman_if == bat_priv->primary_if) {
 		struct batman_if *new_if;

 		new_if = get_active_batman_if(batman_if->soft_iface);
 		set_primary_if(bat_priv, new_if);

 		if (new_if)
 			hardif_put(new_if);
 	}

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

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

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

 	batman_if->soft_iface = NULL;
 }

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

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

 	dev_hold(net_dev);

 	batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC);
 	if (!batman_if) {
 		pr_err("Can't add interface (%s): out of memory\n",
 		       net_dev->name);
 		goto release_dev;
 	}

 	ret = sysfs_add_hardif(&batman_if->hardif_obj, net_dev);
 	if (ret)
 		goto free_if;

 	batman_if->if_num = -1;
 	batman_if->net_dev = net_dev;
 	batman_if->soft_iface = NULL;
 	batman_if->if_status = IF_NOT_IN_USE;
 	INIT_LIST_HEAD(&batman_if->list);
 	atomic_set(&batman_if->refcnt, 0);
 	hardif_hold(batman_if);

 	check_known_mac_addr(batman_if->net_dev);

 	spin_lock(&if_list_lock);
 	list_add_tail_rcu(&batman_if->list, &if_list);
 	spin_unlock(&if_list_lock);

 	/* extra reference for return */
 	hardif_hold(batman_if);
 	return batman_if;

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

 static void hardif_remove_interface(struct batman_if *batman_if)
 {
 	/* first deactivate interface */
 	if (batman_if->if_status != IF_NOT_IN_USE)
 		hardif_disable_interface(batman_if);

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

 	batman_if->if_status = IF_TO_BE_REMOVED;
 	synchronize_rcu();
 	sysfs_del_hardif(&batman_if->hardif_obj);
 	hardif_put(batman_if);
 }

 void hardif_remove_interfaces(void)
 {
 	struct batman_if *batman_if, *batman_if_tmp;
 	struct list_head if_queue;

 	INIT_LIST_HEAD(&if_queue);

 	spin_lock(&if_list_lock);
 	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) {
 		list_del_rcu(&batman_if->list);
 		list_add_tail(&batman_if->list, &if_queue);
 	}
 	spin_unlock(&if_list_lock);

 	rtnl_lock();
 	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_queue, list) {
 		hardif_remove_interface(batman_if);
 	}
 	rtnl_unlock();
 }

 static int hard_if_event(struct notifier_block *this,
 			 unsigned long event, void *ptr)
 {
 	struct net_device *net_dev = (struct net_device *)ptr;
 	struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
 	struct bat_priv *bat_priv;

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

 	if (!batman_if)
 		goto out;

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

 		hardif_remove_interface(batman_if);
 		break;
 	case NETDEV_CHANGEMTU:
 		if (batman_if->soft_iface)
 			update_min_mtu(batman_if->soft_iface);
 		break;
 	case NETDEV_CHANGEADDR:
 		if (batman_if->if_status == IF_NOT_IN_USE) {
 			hardif_put(batman_if);
 			goto out;
 		}

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

 		bat_priv = netdev_priv(batman_if->soft_iface);
 		if (batman_if == bat_priv->primary_if)
 			update_primary_addr(bat_priv);
 		break;
 	default:
 		break;
 	};
 	hardif_put(batman_if);

 out:
 	return NOTIFY_DONE;
 }

 /* receive a packet with the batman ethertype coming on a hard
  * interface */
 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 batman_if *batman_if;
 	int ret;

 	batman_if = container_of(ptype, struct batman_if, 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 (!batman_if->soft_iface)
 		goto err_free;

 	bat_priv = netdev_priv(batman_if->soft_iface);

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

 	/* discard frames on not active interfaces */
 	if (batman_if->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, batman_if);
 		break;

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

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

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

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

 		/* vis packet */
 	case BAT_VIS:
 		ret = recv_vis_packet(skb, batman_if);
 		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;
 }

 struct notifier_block hard_if_notifier = {
 	.notifier_call = hard_if_event,
 };
	/*
	* Copyright (C) 2007-2010 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>

	#define MIN(x, y) ((x) < (y) ? (x) : (y))

	/* protect update critical side of if_list - but not the content */
	static DEFINE_SPINLOCK(if_list_lock);

	struct batman_if get_batman_if_by_netdev(struct net_device net_dev)
	{
	struct batman_if *batman_if;

	rcu_read_lock();
	list_for_each_entry_rcu(batman_if, &if_list, list) {
	if (batman_if->net_dev == net_dev)
	goto out;
	}

	batman_if = NULL;

	out:
	if (batman_if)
	hardif_hold(batman_if);

	rcu_read_unlock();
	return batman_if;
	}

	static int is_valid_iface(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 */
	#ifdef HAVE_NET_DEVICE_OPS
	if (net_dev->netdev_ops->ndo_start_xmit == interface_tx)
	return 0;
	#else
	if (net_dev->hard_start_xmit == interface_tx)
	return 0;
	#endif

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

	return 1;
	}

	static struct batman_if get_active_batman_if(struct net_device soft_iface)
	{
	struct batman_if *batman_if;

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

	if (batman_if->if_status == IF_ACTIVE)
	goto out;
	}

	batman_if = NULL;

	out:
	if (batman_if)
	hardif_hold(batman_if);

	rcu_read_unlock();
	return batman_if;
	}

	static void update_primary_addr(struct bat_priv *bat_priv)
	{
	struct vis_packet *vis_packet;

	vis_packet = (struct vis_packet *)
	bat_priv->my_vis_info->skb_packet->data;
	memcpy(vis_packet->vis_orig,
	bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
	memcpy(vis_packet->sender_orig,
	bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
	}

	static void set_primary_if(struct bat_priv *bat_priv,
	struct batman_if *batman_if)
	{
	struct batman_packet *batman_packet;
	struct batman_if *old_if;

	if (batman_if)
	hardif_hold(batman_if);

	old_if = bat_priv->primary_if;
	bat_priv->primary_if = batman_if;

	if (old_if)
	hardif_put(old_if);

	if (!bat_priv->primary_if)
	return;

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

	update_primary_addr(bat_priv);

	/***
	* hacky trick to make sure that we send the HNA information via
	* our new primary interface
	*/
	atomic_set(&bat_priv->hna_local_changed, 1);
	}

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

	return false;
	}

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

	static void check_known_mac_addr(struct net_device *net_dev)
	{
	struct batman_if *batman_if;

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

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

	if (!compare_orig(batman_if->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,
	batman_if->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)
	{
	struct bat_priv *bat_priv = netdev_priv(soft_iface);
	struct batman_if *batman_if;
	/* 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->frag_enabled))
	goto out;

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

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

	min_mtu = MIN(batman_if->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 batman_if *batman_if)
	{
	struct bat_priv *bat_priv;

	if (batman_if->if_status != IF_INACTIVE)
	return;

	bat_priv = netdev_priv(batman_if->soft_iface);

	update_mac_addresses(batman_if);
	batman_if->if_status = IF_TO_BE_ACTIVATED;

	/**
	* the first active interface becomes our primary interface or
	* the next active interface after the old primay interface was removed
	*/
	if (!bat_priv->primary_if)
	set_primary_if(bat_priv, batman_if);

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

	update_min_mtu(batman_if->soft_iface);
	return;
	}

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

	batman_if->if_status = IF_INACTIVE;

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

	update_min_mtu(batman_if->soft_iface);
	}

	int hardif_enable_interface(struct batman_if batman_if, char iface_name)
	{
	struct bat_priv *bat_priv;
	struct batman_packet *batman_packet;

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

	batman_if->soft_iface = dev_get_by_name(&init_net, iface_name);

	if (!batman_if->soft_iface) {
	batman_if->soft_iface = softif_create(iface_name);

	if (!batman_if->soft_iface)
	goto err;

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

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

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

	batman_packet = (struct batman_packet *)(batman_if->packet_buff);
	batman_packet->packet_type = BAT_PACKET;
	batman_packet->version = COMPAT_VERSION;
	batman_packet->flags = 0;
	batman_packet->ttl = 2;
	batman_packet->tq = TQ_MAX_VALUE;
	batman_packet->num_hna = 0;

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

	batman_if->batman_adv_ptype.type = __constant_htons(ETH_P_BATMAN);
	batman_if->batman_adv_ptype.func = batman_skb_recv;
	batman_if->batman_adv_ptype.dev = batman_if->net_dev;
	hardif_hold(batman_if);
	dev_add_pack(&batman_if->batman_adv_ptype);

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

	if (atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu <
	ETH_DATA_LEN + BAT_HEADER_LEN)
	bat_info(batman_if->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",
	batman_if->net_dev->name, batman_if->net_dev->mtu,
	ETH_DATA_LEN + BAT_HEADER_LEN);

	if (!atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu <
	ETH_DATA_LEN + BAT_HEADER_LEN)
	bat_info(batman_if->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",
	batman_if->net_dev->name, batman_if->net_dev->mtu,
	ETH_DATA_LEN + BAT_HEADER_LEN);

	if (hardif_is_iface_up(batman_if))
	hardif_activate_interface(batman_if);
	else
	bat_err(batman_if->soft_iface, "Not using interface %s "
	"(retrying later): interface not active\n",
	batman_if->net_dev->name);

	/* begin scheduling originator messages on that interface */
	schedule_own_packet(batman_if);

	out:
	return 0;

	err:
	return -ENOMEM;
	}

	void hardif_disable_interface(struct batman_if *batman_if)
	{
	struct bat_priv *bat_priv = netdev_priv(batman_if->soft_iface);

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

	if (batman_if->if_status != IF_INACTIVE)
	return;

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

	bat_priv->num_ifaces--;
	orig_hash_del_if(batman_if, bat_priv->num_ifaces);

	if (batman_if == bat_priv->primary_if) {
	struct batman_if *new_if;

	new_if = get_active_batman_if(batman_if->soft_iface);
	set_primary_if(bat_priv, new_if);

	if (new_if)
	hardif_put(new_if);
	}

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

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

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

	batman_if->soft_iface = NULL;
	}

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

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

	dev_hold(net_dev);

	batman_if = kmalloc(sizeof(struct batman_if), GFP_ATOMIC);
	if (!batman_if) {
	pr_err("Can't add interface (%s): out of memory\n",
	net_dev->name);
	goto release_dev;
	}

	ret = sysfs_add_hardif(&batman_if->hardif_obj, net_dev);
	if (ret)
	goto free_if;

	batman_if->if_num = -1;
	batman_if->net_dev = net_dev;
	batman_if->soft_iface = NULL;
	batman_if->if_status = IF_NOT_IN_USE;
	INIT_LIST_HEAD(&batman_if->list);
	atomic_set(&batman_if->refcnt, 0);
	hardif_hold(batman_if);

	check_known_mac_addr(batman_if->net_dev);

	spin_lock(&if_list_lock);
	list_add_tail_rcu(&batman_if->list, &if_list);
	spin_unlock(&if_list_lock);

	/* extra reference for return */
	hardif_hold(batman_if);
	return batman_if;

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

	static void hardif_remove_interface(struct batman_if *batman_if)
	{
	/* first deactivate interface */
	if (batman_if->if_status != IF_NOT_IN_USE)
	hardif_disable_interface(batman_if);

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

	batman_if->if_status = IF_TO_BE_REMOVED;
	synchronize_rcu();
	sysfs_del_hardif(&batman_if->hardif_obj);
	hardif_put(batman_if);
	}

	void hardif_remove_interfaces(void)
	{
	struct batman_if batman_if, batman_if_tmp;
	struct list_head if_queue;

	INIT_LIST_HEAD(&if_queue);

	spin_lock(&if_list_lock);
	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_list, list) {
	list_del_rcu(&batman_if->list);
	list_add_tail(&batman_if->list, &if_queue);
	}
	spin_unlock(&if_list_lock);

	rtnl_lock();
	list_for_each_entry_safe(batman_if, batman_if_tmp, &if_queue, list) {
	hardif_remove_interface(batman_if);
	}
	rtnl_unlock();
	}

	static int hard_if_event(struct notifier_block *this,
	unsigned long event, void *ptr)
	{
	struct net_device net_dev = (struct net_device )ptr;
	struct batman_if *batman_if = get_batman_if_by_netdev(net_dev);
	struct bat_priv *bat_priv;

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

	if (!batman_if)
	goto out;

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

	hardif_remove_interface(batman_if);
	break;
	case NETDEV_CHANGEMTU:
	if (batman_if->soft_iface)
	update_min_mtu(batman_if->soft_iface);
	break;
	case NETDEV_CHANGEADDR:
	if (batman_if->if_status == IF_NOT_IN_USE) {
	hardif_put(batman_if);
	goto out;
	}

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

	bat_priv = netdev_priv(batman_if->soft_iface);
	if (batman_if == bat_priv->primary_if)
	update_primary_addr(bat_priv);
	break;
	default:
	break;
	};
	hardif_put(batman_if);

	out:
	return NOTIFY_DONE;
	}

	/* receive a packet with the batman ethertype coming on a hard
	* interface */
	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 batman_if *batman_if;
	int ret;

	batman_if = container_of(ptype, struct batman_if, 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 (!batman_if->soft_iface)
	goto err_free;

	bat_priv = netdev_priv(batman_if->soft_iface);

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

	/* discard frames on not active interfaces */
	if (batman_if->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, batman_if);
	break;

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

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

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

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

	/* vis packet */
	case BAT_VIS:
	ret = recv_vis_packet(skb, batman_if);
	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;
	}

	struct notifier_block hard_if_notifier = {
	.notifier_call = hard_if_event,
	};