soft-interface.c

/* Copyright (C) 2007-2015 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, see <http://www.gnu.org/licenses/>.
 */

#include "soft-interface.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/fs.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/percpu.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include "bridge_loop_avoidance.h"
#include "debugfs.h"
#include "distributed-arp-table.h"
#include "gateway_client.h"
#include "gateway_common.h"
#include "hard-interface.h"
#include "multicast.h"
#include "network-coding.h"
#include "packet.h"
#include "send.h"
#include "sysfs.h"
#include "translation-table.h"

static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd);
static void batadv_get_drvinfo(struct net_device *dev,
			       struct ethtool_drvinfo *info);
static u32 batadv_get_msglevel(struct net_device *dev);
static void batadv_set_msglevel(struct net_device *dev, u32 value);
static u32 batadv_get_link(struct net_device *dev);
static void batadv_get_strings(struct net_device *dev, u32 stringset, u8 *data);
static void batadv_get_ethtool_stats(struct net_device *dev,
				     struct ethtool_stats *stats, u64 *data);
static int batadv_get_sset_count(struct net_device *dev, int stringset);

static const struct ethtool_ops batadv_ethtool_ops = {
	.get_settings = batadv_get_settings,
	.get_drvinfo = batadv_get_drvinfo,
	.get_msglevel = batadv_get_msglevel,
	.set_msglevel = batadv_set_msglevel,
	.get_link = batadv_get_link,
	.get_strings = batadv_get_strings,
	.get_ethtool_stats = batadv_get_ethtool_stats,
	.get_sset_count = batadv_get_sset_count,
};

int batadv_skb_head_push(struct sk_buff *skb, unsigned int len)
{
	int result;

	/* TODO: We must check if we can release all references to non-payload
	 * data using skb_header_release in our skbs to allow skb_cow_header to
	 * work optimally. This means that those skbs are not allowed to read
	 * or write any data which is before the current position of skb->data
	 * after that call and thus allow other skbs with the same data buffer
	 * to write freely in that area.
	 */
	result = skb_cow_head(skb, len);
	if (result < 0)
		return result;

	skb_push(skb, len);
	return 0;
}

static int batadv_interface_open(struct net_device *dev)
{
	netif_start_queue(dev);
	return 0;
}

static int batadv_interface_release(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

static struct net_device_stats *batadv_interface_stats(struct net_device *dev)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	struct net_device_stats *stats = &bat_priv->stats;

	stats->tx_packets = batadv_sum_counter(bat_priv, BATADV_CNT_TX);
	stats->tx_bytes = batadv_sum_counter(bat_priv, BATADV_CNT_TX_BYTES);
	stats->tx_dropped = batadv_sum_counter(bat_priv, BATADV_CNT_TX_DROPPED);
	stats->rx_packets = batadv_sum_counter(bat_priv, BATADV_CNT_RX);
	stats->rx_bytes = batadv_sum_counter(bat_priv, BATADV_CNT_RX_BYTES);
	return stats;
}

static int batadv_interface_set_mac_addr(struct net_device *dev, void *p)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	struct batadv_softif_vlan *vlan;
	struct sockaddr *addr = p;
	u8 old_addr[ETH_ALEN];

	if (!is_valid_ether_addr(addr->sa_data))
		return -EADDRNOTAVAIL;

	ether_addr_copy(old_addr, dev->dev_addr);
	ether_addr_copy(dev->dev_addr, addr->sa_data);

	/* only modify transtable if it has been initialized before */
	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		return 0;

	rcu_read_lock();
	hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
		batadv_tt_local_remove(bat_priv, old_addr, vlan->vid,
				       "mac address changed", false);
		batadv_tt_local_add(dev, addr->sa_data, vlan->vid,
				    BATADV_NULL_IFINDEX, BATADV_NO_MARK);
	}
	rcu_read_unlock();

	return 0;
}

static int batadv_interface_change_mtu(struct net_device *dev, int new_mtu)
{
	/* check ranges */
	if ((new_mtu < 68) || (new_mtu > batadv_hardif_min_mtu(dev)))
		return -EINVAL;

	dev->mtu = new_mtu;

	return 0;
}

/**
 * batadv_interface_set_rx_mode - set the rx mode of a device
 * @dev: registered network device to modify
 *
 * We do not actually need to set any rx filters for the virtual batman
 * soft interface. However a dummy handler enables a user to set static
 * multicast listeners for instance.
 */
static void batadv_interface_set_rx_mode(struct net_device *dev)
{
}

static int batadv_interface_tx(struct sk_buff *skb,
			       struct net_device *soft_iface)
{
	struct ethhdr *ethhdr;
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
	struct batadv_hard_iface *primary_if = NULL;
	struct batadv_bcast_packet *bcast_packet;
	__be16 ethertype = htons(ETH_P_BATMAN);
	static const u8 stp_addr[ETH_ALEN] = {0x01, 0x80, 0xC2, 0x00,
					      0x00, 0x00};
	static const u8 ectp_addr[ETH_ALEN] = {0xCF, 0x00, 0x00, 0x00,
					       0x00, 0x00};
	enum batadv_dhcp_recipient dhcp_rcp = BATADV_DHCP_NO;
	u8 *dst_hint = NULL, chaddr[ETH_ALEN];
	struct vlan_ethhdr *vhdr;
	unsigned int header_len = 0;
	int data_len = skb->len, ret;
	unsigned long brd_delay = 1;
	bool do_bcast = false, client_added;
	unsigned short vid;
	u32 seqno;
	int gw_mode;
	enum batadv_forw_mode forw_mode;
	struct batadv_orig_node *mcast_single_orig = NULL;
	int network_offset = ETH_HLEN;

	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		goto dropped;

	soft_iface->trans_start = jiffies;
	vid = batadv_get_vid(skb, 0);
	ethhdr = eth_hdr(skb);

	switch (ntohs(ethhdr->h_proto)) {
	case ETH_P_8021Q:
		vhdr = vlan_eth_hdr(skb);

		if (vhdr->h_vlan_encapsulated_proto != ethertype) {
			network_offset += VLAN_HLEN;
			break;
		}

		/* fall through */
	case ETH_P_BATMAN:
		goto dropped;
	}

	skb_set_network_header(skb, network_offset);

	if (batadv_bla_tx(bat_priv, skb, vid))
		goto dropped;

	/* skb->data might have been reallocated by batadv_bla_tx() */
	ethhdr = eth_hdr(skb);

	/* Register the client MAC in the transtable */
	if (!is_multicast_ether_addr(ethhdr->h_source)) {
		client_added = batadv_tt_local_add(soft_iface, ethhdr->h_source,
						   vid, skb->skb_iif,
						   skb->mark);
		if (!client_added)
			goto dropped;
	}

	/* don't accept stp packets. STP does not help in meshes.
	 * better use the bridge loop avoidance ...
	 *
	 * The same goes for ECTP sent at least by some Cisco Switches,
	 * it might confuse the mesh when used with bridge loop avoidance.
	 */
	if (batadv_compare_eth(ethhdr->h_dest, stp_addr))
		goto dropped;

	if (batadv_compare_eth(ethhdr->h_dest, ectp_addr))
		goto dropped;

	gw_mode = atomic_read(&bat_priv->gw_mode);
	if (is_multicast_ether_addr(ethhdr->h_dest)) {
		/* if gw mode is off, broadcast every packet */
		if (gw_mode == BATADV_GW_MODE_OFF) {
			do_bcast = true;
			goto send;
		}

		dhcp_rcp = batadv_gw_dhcp_recipient_get(skb, &header_len,
							chaddr);
		/* skb->data may have been modified by
		 * batadv_gw_dhcp_recipient_get()
		 */
		ethhdr = eth_hdr(skb);
		/* if gw_mode is on, broadcast any non-DHCP message.
		 * All the DHCP packets are going to be sent as unicast
		 */
		if (dhcp_rcp == BATADV_DHCP_NO) {
			do_bcast = true;
			goto send;
		}

		if (dhcp_rcp == BATADV_DHCP_TO_CLIENT)
			dst_hint = chaddr;
		else if ((gw_mode == BATADV_GW_MODE_SERVER) &&
			 (dhcp_rcp == BATADV_DHCP_TO_SERVER))
			/* gateways should not forward any DHCP message if
			 * directed to a DHCP server
			 */
			goto dropped;

send:
		if (do_bcast && !is_broadcast_ether_addr(ethhdr->h_dest)) {
			forw_mode = batadv_mcast_forw_mode(bat_priv, skb,
							   &mcast_single_orig);
			if (forw_mode == BATADV_FORW_NONE)
				goto dropped;

			if (forw_mode == BATADV_FORW_SINGLE)
				do_bcast = false;
		}
	}

	batadv_skb_set_priority(skb, 0);

	/* ethernet packet should be broadcasted */
	if (do_bcast) {
		primary_if = batadv_primary_if_get_selected(bat_priv);
		if (!primary_if)
			goto dropped;

		/* in case of ARP request, we do not immediately broadcasti the
		 * packet, instead we first wait for DAT to try to retrieve the
		 * correct ARP entry
		 */
		if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb))
			brd_delay = msecs_to_jiffies(ARP_REQ_DELAY);

		if (batadv_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
			goto dropped;

		bcast_packet = (struct batadv_bcast_packet *)skb->data;
		bcast_packet->version = BATADV_COMPAT_VERSION;
		bcast_packet->ttl = BATADV_TTL;

		/* batman packet type: broadcast */
		bcast_packet->packet_type = BATADV_BCAST;
		bcast_packet->reserved = 0;

		/* hw address of first interface is the orig mac because only
		 * this mac is known throughout the mesh
		 */
		ether_addr_copy(bcast_packet->orig,
				primary_if->net_dev->dev_addr);

		/* set broadcast sequence number */
		seqno = atomic_inc_return(&bat_priv->bcast_seqno);
		bcast_packet->seqno = htonl(seqno);

		batadv_add_bcast_packet_to_list(bat_priv, skb, brd_delay);

		/* a copy is stored in the bcast list, therefore removing
		 * the original skb.
		 */
		kfree_skb(skb);

	/* unicast packet */
	} else {
		/* DHCP packets going to a server will use the GW feature */
		if (dhcp_rcp == BATADV_DHCP_TO_SERVER) {
			ret = batadv_gw_out_of_range(bat_priv, skb);
			if (ret)
				goto dropped;
			ret = batadv_send_skb_via_gw(bat_priv, skb, vid);
		} else if (mcast_single_orig) {
			ret = batadv_send_skb_unicast(bat_priv, skb,
						      BATADV_UNICAST, 0,
						      mcast_single_orig, vid);
		} else {
			if (batadv_dat_snoop_outgoing_arp_request(bat_priv,
								  skb))
				goto dropped;

			batadv_dat_snoop_outgoing_arp_reply(bat_priv, skb);

			ret = batadv_send_skb_via_tt(bat_priv, skb, dst_hint,
						     vid);
		}
		if (ret == NET_XMIT_DROP)
			goto dropped_freed;
	}

	batadv_inc_counter(bat_priv, BATADV_CNT_TX);
	batadv_add_counter(bat_priv, BATADV_CNT_TX_BYTES, data_len);
	goto end;

dropped:
	kfree_skb(skb);
dropped_freed:
	batadv_inc_counter(bat_priv, BATADV_CNT_TX_DROPPED);
end:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return NETDEV_TX_OK;
}

void batadv_interface_rx(struct net_device *soft_iface,
			 struct sk_buff *skb, struct batadv_hard_iface *recv_if,
			 int hdr_size, struct batadv_orig_node *orig_node)
{
	struct batadv_bcast_packet *batadv_bcast_packet;
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
	__be16 ethertype = htons(ETH_P_BATMAN);
	struct vlan_ethhdr *vhdr;
	struct ethhdr *ethhdr;
	unsigned short vid;
	bool is_bcast;

	batadv_bcast_packet = (struct batadv_bcast_packet *)skb->data;
	is_bcast = (batadv_bcast_packet->packet_type == BATADV_BCAST);

	/* check if enough space is available for pulling, and pull */
	if (!pskb_may_pull(skb, hdr_size))
		goto dropped;

	skb_pull_rcsum(skb, hdr_size);
	skb_reset_mac_header(skb);

	/* clean the netfilter state now that the batman-adv header has been
	 * removed
	 */
	nf_reset(skb);

	vid = batadv_get_vid(skb, 0);
	ethhdr = eth_hdr(skb);

	switch (ntohs(ethhdr->h_proto)) {
	case ETH_P_8021Q:
		vhdr = (struct vlan_ethhdr *)skb->data;

		if (vhdr->h_vlan_encapsulated_proto != ethertype)
			break;

		/* fall through */
	case ETH_P_BATMAN:
		goto dropped;
	}

	/* skb->dev & skb->pkt_type are set here */
	if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
		goto dropped;
	skb->protocol = eth_type_trans(skb, soft_iface);

	/* should not be necessary anymore as we use skb_pull_rcsum()
	 * TODO: please verify this and remove this TODO
	 * -- Dec 21st 2009, Simon Wunderlich
	 */

	/* skb->ip_summed = CHECKSUM_UNNECESSARY; */

	batadv_inc_counter(bat_priv, BATADV_CNT_RX);
	batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
			   skb->len + ETH_HLEN);

	soft_iface->last_rx = jiffies;

	/* Let the bridge loop avoidance check the packet. If will
	 * not handle it, we can safely push it up.
	 */
	if (batadv_bla_rx(bat_priv, skb, vid, is_bcast))
		goto out;

	if (orig_node)
		batadv_tt_add_temporary_global_entry(bat_priv, orig_node,
						     ethhdr->h_source, vid);

	if (is_multicast_ether_addr(ethhdr->h_dest)) {
		/* set the mark on broadcast packets if AP isolation is ON and
		 * the packet is coming from an "isolated" client
		 */
		if (batadv_vlan_ap_isola_get(bat_priv, vid) &&
		    batadv_tt_global_is_isolated(bat_priv, ethhdr->h_source,
						 vid)) {
			/* save bits in skb->mark not covered by the mask and
			 * apply the mark on the rest
			 */
			skb->mark &= ~bat_priv->isolation_mark_mask;
			skb->mark |= bat_priv->isolation_mark;
		}
	} else if (batadv_is_ap_isolated(bat_priv, ethhdr->h_source,
					 ethhdr->h_dest, vid)) {
		goto dropped;
	}

	netif_rx(skb);
	goto out;

dropped:
	kfree_skb(skb);
out:
	return;
}

/**
 * batadv_softif_vlan_free_ref - decrease the vlan object refcounter and
 *  possibly free it
 * @softif_vlan: the vlan object to release
 */
void batadv_softif_vlan_free_ref(struct batadv_softif_vlan *vlan)
{
	if (!vlan)
		return;

	if (atomic_dec_and_test(&vlan->refcount)) {
		spin_lock_bh(&vlan->bat_priv->softif_vlan_list_lock);
		hlist_del_rcu(&vlan->list);
		spin_unlock_bh(&vlan->bat_priv->softif_vlan_list_lock);

		kfree_rcu(vlan, rcu);
	}
}

/**
 * batadv_softif_vlan_get - get the vlan object for a specific vid
 * @bat_priv: the bat priv with all the soft interface information
 * @vid: the identifier of the vlan object to retrieve
 *
 * Returns the private data of the vlan matching the vid passed as argument or
 * NULL otherwise. The refcounter of the returned object is incremented by 1.
 */
struct batadv_softif_vlan *batadv_softif_vlan_get(struct batadv_priv *bat_priv,
						  unsigned short vid)
{
	struct batadv_softif_vlan *vlan_tmp, *vlan = NULL;

	rcu_read_lock();
	hlist_for_each_entry_rcu(vlan_tmp, &bat_priv->softif_vlan_list, list) {
		if (vlan_tmp->vid != vid)
			continue;

		if (!atomic_inc_not_zero(&vlan_tmp->refcount))
			continue;

		vlan = vlan_tmp;
		break;
	}
	rcu_read_unlock();

	return vlan;
}

/**
 * batadv_create_vlan - allocate the needed resources for a new vlan
 * @bat_priv: the bat priv with all the soft interface information
 * @vid: the VLAN identifier
 *
 * Returns 0 on success, a negative error otherwise.
 */
int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
{
	struct batadv_softif_vlan *vlan;
	int err;

	vlan = batadv_softif_vlan_get(bat_priv, vid);
	if (vlan) {
		batadv_softif_vlan_free_ref(vlan);
		return -EEXIST;
	}

	vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC);
	if (!vlan)
		return -ENOMEM;

	vlan->bat_priv = bat_priv;
	vlan->vid = vid;
	atomic_set(&vlan->refcount, 1);

	atomic_set(&vlan->ap_isolation, 0);

	err = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan);
	if (err) {
		kfree(vlan);
		return err;
	}

	spin_lock_bh(&bat_priv->softif_vlan_list_lock);
	hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list);
	spin_unlock_bh(&bat_priv->softif_vlan_list_lock);

	/* add a new TT local entry. This one will be marked with the NOPURGE
	 * flag
	 */
	batadv_tt_local_add(bat_priv->soft_iface,
			    bat_priv->soft_iface->dev_addr, vid,
			    BATADV_NULL_IFINDEX, BATADV_NO_MARK);

	return 0;
}

/**
 * batadv_softif_destroy_vlan - remove and destroy a softif_vlan object
 * @bat_priv: the bat priv with all the soft interface information
 * @vlan: the object to remove
 */
static void batadv_softif_destroy_vlan(struct batadv_priv *bat_priv,
				       struct batadv_softif_vlan *vlan)
{
	/* explicitly remove the associated TT local entry because it is marked
	 * with the NOPURGE flag
	 */
	batadv_tt_local_remove(bat_priv, bat_priv->soft_iface->dev_addr,
			       vlan->vid, "vlan interface destroyed", false);

	batadv_sysfs_del_vlan(bat_priv, vlan);
	batadv_softif_vlan_free_ref(vlan);
}

/**
 * batadv_interface_add_vid - ndo_add_vid API implementation
 * @dev: the netdev of the mesh interface
 * @vid: identifier of the new vlan
 *
 * Set up all the internal structures for handling the new vlan on top of the
 * mesh interface
 *
 * Returns 0 on success or a negative error code in case of failure.
 */
static int batadv_interface_add_vid(struct net_device *dev, __be16 proto,
				    unsigned short vid)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	struct batadv_softif_vlan *vlan;
	int ret;

	/* only 802.1Q vlans are supported.
	 * batman-adv does not know how to handle other types
	 */
	if (proto != htons(ETH_P_8021Q))
		return -EINVAL;

	vid |= BATADV_VLAN_HAS_TAG;

	/* if a new vlan is getting created and it already exists, it means that
	 * it was not deleted yet. batadv_softif_vlan_get() increases the
	 * refcount in order to revive the object.
	 *
	 * if it does not exist then create it.
	 */
	vlan = batadv_softif_vlan_get(bat_priv, vid);
	if (!vlan)
		return batadv_softif_create_vlan(bat_priv, vid);

	/* recreate the sysfs object if it was already destroyed (and it should
	 * be since we received a kill_vid() for this vlan
	 */
	if (!vlan->kobj) {
		ret = batadv_sysfs_add_vlan(bat_priv->soft_iface, vlan);
		if (ret) {
			batadv_softif_vlan_free_ref(vlan);
			return ret;
		}
	}

	/* add a new TT local entry. This one will be marked with the NOPURGE
	 * flag. This must be added again, even if the vlan object already
	 * exists, because the entry was deleted by kill_vid()
	 */
	batadv_tt_local_add(bat_priv->soft_iface,
			    bat_priv->soft_iface->dev_addr, vid,
			    BATADV_NULL_IFINDEX, BATADV_NO_MARK);

	return 0;
}

/**
 * batadv_interface_kill_vid - ndo_kill_vid API implementation
 * @dev: the netdev of the mesh interface
 * @vid: identifier of the deleted vlan
 *
 * Destroy all the internal structures used to handle the vlan identified by vid
 * on top of the mesh interface
 *
 * Returns 0 on success, -EINVAL if the specified prototype is not ETH_P_8021Q
 * or -ENOENT if the specified vlan id wasn't registered.
 */
static int batadv_interface_kill_vid(struct net_device *dev, __be16 proto,
				     unsigned short vid)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	struct batadv_softif_vlan *vlan;

	/* only 802.1Q vlans are supported. batman-adv does not know how to
	 * handle other types
	 */
	if (proto != htons(ETH_P_8021Q))
		return -EINVAL;

	vlan = batadv_softif_vlan_get(bat_priv, vid | BATADV_VLAN_HAS_TAG);
	if (!vlan)
		return -ENOENT;

	batadv_softif_destroy_vlan(bat_priv, vlan);

	/* finally free the vlan object */
	batadv_softif_vlan_free_ref(vlan);

	return 0;
}

/* batman-adv network devices have devices nesting below it and are a special
 * "super class" of normal network devices; split their locks off into a
 * separate class since they always nest.
 */
static struct lock_class_key batadv_netdev_xmit_lock_key;
static struct lock_class_key batadv_netdev_addr_lock_key;

/**
 * batadv_set_lockdep_class_one - Set lockdep class for a single tx queue
 * @dev: device which owns the tx queue
 * @txq: tx queue to modify
 * @_unused: always NULL
 */
static void batadv_set_lockdep_class_one(struct net_device *dev,
					 struct netdev_queue *txq,
					 void *_unused)
{
	lockdep_set_class(&txq->_xmit_lock, &batadv_netdev_xmit_lock_key);
}

/**
 * batadv_set_lockdep_class - Set txq and addr_list lockdep class
 * @dev: network device to modify
 */
static void batadv_set_lockdep_class(struct net_device *dev)
{
	lockdep_set_class(&dev->addr_list_lock, &batadv_netdev_addr_lock_key);
	netdev_for_each_tx_queue(dev, batadv_set_lockdep_class_one, NULL);
}

/**
 * batadv_softif_destroy_finish - cleans up the remains of a softif
 * @work: work queue item
 *
 * Free the parts of the soft interface which can not be removed under
 * rtnl lock (to prevent deadlock situations).
 */
static void batadv_softif_destroy_finish(struct work_struct *work)
{
	struct batadv_softif_vlan *vlan;
	struct batadv_priv *bat_priv;
	struct net_device *soft_iface;

	bat_priv = container_of(work, struct batadv_priv,
				cleanup_work);
	soft_iface = bat_priv->soft_iface;

	/* destroy the "untagged" VLAN */
	vlan = batadv_softif_vlan_get(bat_priv, BATADV_NO_FLAGS);
	if (vlan) {
		batadv_softif_destroy_vlan(bat_priv, vlan);
		batadv_softif_vlan_free_ref(vlan);
	}

	batadv_sysfs_del_meshif(soft_iface);
	unregister_netdev(soft_iface);
}

/**
 * batadv_softif_init_late - late stage initialization of soft interface
 * @dev: registered network device to modify
 *
 * Returns error code on failures
 */
static int batadv_softif_init_late(struct net_device *dev)
{
	struct batadv_priv *bat_priv;
	u32 random_seqno;
	int ret;
	size_t cnt_len = sizeof(u64) * BATADV_CNT_NUM;

	batadv_set_lockdep_class(dev);

	bat_priv = netdev_priv(dev);
	bat_priv->soft_iface = dev;
	INIT_WORK(&bat_priv->cleanup_work, batadv_softif_destroy_finish);

	/* batadv_interface_stats() needs to be available as soon as
	 * register_netdevice() has been called
	 */
	bat_priv->bat_counters = __alloc_percpu(cnt_len, __alignof__(u64));
	if (!bat_priv->bat_counters)
		return -ENOMEM;

	atomic_set(&bat_priv->aggregated_ogms, 1);
	atomic_set(&bat_priv->bonding, 0);
#ifdef CONFIG_BATMAN_ADV_BLA
	atomic_set(&bat_priv->bridge_loop_avoidance, 1);
#endif
#ifdef CONFIG_BATMAN_ADV_DAT
	atomic_set(&bat_priv->distributed_arp_table, 1);
#endif
#ifdef CONFIG_BATMAN_ADV_MCAST
	bat_priv->mcast.flags = BATADV_NO_FLAGS;
	atomic_set(&bat_priv->multicast_mode, 1);
	atomic_set(&bat_priv->mcast.num_disabled, 0);
	atomic_set(&bat_priv->mcast.num_want_all_unsnoopables, 0);
	atomic_set(&bat_priv->mcast.num_want_all_ipv4, 0);
	atomic_set(&bat_priv->mcast.num_want_all_ipv6, 0);
#endif
	atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
	atomic_set(&bat_priv->gw_sel_class, 20);
	atomic_set(&bat_priv->gw.bandwidth_down, 100);
	atomic_set(&bat_priv->gw.bandwidth_up, 20);
	atomic_set(&bat_priv->orig_interval, 1000);
	atomic_set(&bat_priv->hop_penalty, 30);
#ifdef CONFIG_BATMAN_ADV_DEBUG
	atomic_set(&bat_priv->log_level, 0);
#endif
	atomic_set(&bat_priv->fragmentation, 1);
	atomic_set(&bat_priv->packet_size_max, ETH_DATA_LEN);
	atomic_set(&bat_priv->bcast_queue_left, BATADV_BCAST_QUEUE_LEN);
	atomic_set(&bat_priv->batman_queue_left, BATADV_BATMAN_QUEUE_LEN);

	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
	atomic_set(&bat_priv->bcast_seqno, 1);
	atomic_set(&bat_priv->tt.vn, 0);
	atomic_set(&bat_priv->tt.local_changes, 0);
	atomic_set(&bat_priv->tt.ogm_append_cnt, 0);
#ifdef CONFIG_BATMAN_ADV_BLA
	atomic_set(&bat_priv->bla.num_requests, 0);
#endif
	bat_priv->tt.last_changeset = NULL;
	bat_priv->tt.last_changeset_len = 0;
	bat_priv->isolation_mark = 0;
	bat_priv->isolation_mark_mask = 0;

	/* randomize initial seqno to avoid collision */
	get_random_bytes(&random_seqno, sizeof(random_seqno));
	atomic_set(&bat_priv->frag_seqno, random_seqno);

	bat_priv->primary_if = NULL;
	bat_priv->num_ifaces = 0;

	batadv_nc_init_bat_priv(bat_priv);

	ret = batadv_algo_select(bat_priv, batadv_routing_algo);
	if (ret < 0)
		goto free_bat_counters;

	ret = batadv_debugfs_add_meshif(dev);
	if (ret < 0)
		goto free_bat_counters;

	ret = batadv_mesh_init(dev);
	if (ret < 0)
		goto unreg_debugfs;

	return 0;

unreg_debugfs:
	batadv_debugfs_del_meshif(dev);
free_bat_counters:
	free_percpu(bat_priv->bat_counters);
	bat_priv->bat_counters = NULL;

	return ret;
}

/**
 * batadv_softif_slave_add - Add a slave interface to a batadv_soft_interface
 * @dev: batadv_soft_interface used as master interface
 * @slave_dev: net_device which should become the slave interface
 *
 * Return 0 if successful or error otherwise.
 */
static int batadv_softif_slave_add(struct net_device *dev,
				   struct net_device *slave_dev)
{
	struct batadv_hard_iface *hard_iface;
	int ret = -EINVAL;

	hard_iface = batadv_hardif_get_by_netdev(slave_dev);
	if (!hard_iface || hard_iface->soft_iface)
		goto out;

	ret = batadv_hardif_enable_interface(hard_iface, dev->name);

out:
	if (hard_iface)
		batadv_hardif_free_ref(hard_iface);
	return ret;
}

/**
 * batadv_softif_slave_del - Delete a slave iface from a batadv_soft_interface
 * @dev: batadv_soft_interface used as master interface
 * @slave_dev: net_device which should be removed from the master interface
 *
 * Return 0 if successful or error otherwise.
 */
static int batadv_softif_slave_del(struct net_device *dev,
				   struct net_device *slave_dev)
{
	struct batadv_hard_iface *hard_iface;
	int ret = -EINVAL;

	hard_iface = batadv_hardif_get_by_netdev(slave_dev);

	if (!hard_iface || hard_iface->soft_iface != dev)
		goto out;

	batadv_hardif_disable_interface(hard_iface, BATADV_IF_CLEANUP_KEEP);
	ret = 0;

out:
	if (hard_iface)
		batadv_hardif_free_ref(hard_iface);
	return ret;
}

static const struct net_device_ops batadv_netdev_ops = {
	.ndo_init = batadv_softif_init_late,
	.ndo_open = batadv_interface_open,
	.ndo_stop = batadv_interface_release,
	.ndo_get_stats = batadv_interface_stats,
	.ndo_vlan_rx_add_vid = batadv_interface_add_vid,
	.ndo_vlan_rx_kill_vid = batadv_interface_kill_vid,
	.ndo_set_mac_address = batadv_interface_set_mac_addr,
	.ndo_change_mtu = batadv_interface_change_mtu,
	.ndo_set_rx_mode = batadv_interface_set_rx_mode,
	.ndo_start_xmit = batadv_interface_tx,
	.ndo_validate_addr = eth_validate_addr,
	.ndo_add_slave = batadv_softif_slave_add,
	.ndo_del_slave = batadv_softif_slave_del,
};

/**
 * batadv_softif_free - Deconstructor of batadv_soft_interface
 * @dev: Device to cleanup and remove
 */
static void batadv_softif_free(struct net_device *dev)
{
	batadv_debugfs_del_meshif(dev);
	batadv_mesh_free(dev);

	/* some scheduled RCU callbacks need the bat_priv struct to accomplish
	 * their tasks. Wait for them all to be finished before freeing the
	 * netdev and its private data (bat_priv)
	 */
	rcu_barrier();

	free_netdev(dev);
}

/**
 * batadv_softif_init_early - early stage initialization of soft interface
 * @dev: registered network device to modify
 */
static void batadv_softif_init_early(struct net_device *dev)
{
	struct batadv_priv *priv = netdev_priv(dev);

	ether_setup(dev);

	dev->netdev_ops = &batadv_netdev_ops;
	dev->destructor = batadv_softif_free;
	dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
	dev->priv_flags |= IFF_NO_QUEUE;

	/* can't call min_mtu, because the needed variables
	 * have not been initialized yet
	 */
	dev->mtu = ETH_DATA_LEN;

	/* generate random address */
	eth_hw_addr_random(dev);

	dev->ethtool_ops = &batadv_ethtool_ops;

	memset(priv, 0, sizeof(*priv));
}

struct net_device *batadv_softif_create(const char *name)
{
	struct net_device *soft_iface;
	int ret;

	soft_iface = alloc_netdev(sizeof(struct batadv_priv), name,
				  NET_NAME_UNKNOWN, batadv_softif_init_early);
	if (!soft_iface)
		return NULL;

	soft_iface->rtnl_link_ops = &batadv_link_ops;

	ret = register_netdevice(soft_iface);
	if (ret < 0) {
		pr_err("Unable to register the batman interface '%s': %i\n",
		       name, ret);
		free_netdev(soft_iface);
		return NULL;
	}

	return soft_iface;
}

/**
 * batadv_softif_destroy_sysfs - deletion of batadv_soft_interface via sysfs
 * @soft_iface: the to-be-removed batman-adv interface
 */
void batadv_softif_destroy_sysfs(struct net_device *soft_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);

	queue_work(batadv_event_workqueue, &bat_priv->cleanup_work);
}

/**
 * batadv_softif_destroy_netlink - deletion of batadv_soft_interface via netlink
 * @soft_iface: the to-be-removed batman-adv interface
 * @head: list pointer
 */
static void batadv_softif_destroy_netlink(struct net_device *soft_iface,
					  struct list_head *head)
{
	struct batadv_hard_iface *hard_iface;

	list_for_each_entry(hard_iface, &batadv_hardif_list, list) {
		if (hard_iface->soft_iface == soft_iface)
			batadv_hardif_disable_interface(hard_iface,
							BATADV_IF_CLEANUP_KEEP);
	}

	batadv_sysfs_del_meshif(soft_iface);
	unregister_netdevice_queue(soft_iface, head);
}

int batadv_softif_is_valid(const struct net_device *net_dev)
{
	if (net_dev->netdev_ops->ndo_start_xmit == batadv_interface_tx)
		return 1;

	return 0;
}

struct rtnl_link_ops batadv_link_ops __read_mostly = {
	.kind		= "batadv",
	.priv_size	= sizeof(struct batadv_priv),
	.setup		= batadv_softif_init_early,
	.dellink	= batadv_softif_destroy_netlink,
};

/* ethtool */
static int batadv_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported = 0;
	cmd->advertising = 0;
	ethtool_cmd_speed_set(cmd, SPEED_10);
	cmd->duplex = DUPLEX_FULL;
	cmd->port = PORT_TP;
	cmd->phy_address = 0;
	cmd->transceiver = XCVR_INTERNAL;
	cmd->autoneg = AUTONEG_DISABLE;
	cmd->maxtxpkt = 0;
	cmd->maxrxpkt = 0;

	return 0;
}

static void batadv_get_drvinfo(struct net_device *dev,
			       struct ethtool_drvinfo *info)
{
	strlcpy(info->driver, "B.A.T.M.A.N. advanced", sizeof(info->driver));
	strlcpy(info->version, BATADV_SOURCE_VERSION, sizeof(info->version));
	strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
	strlcpy(info->bus_info, "batman", sizeof(info->bus_info));
}

static u32 batadv_get_msglevel(struct net_device *dev)
{
	return -EOPNOTSUPP;
}

static void batadv_set_msglevel(struct net_device *dev, u32 value)
{
}

static u32 batadv_get_link(struct net_device *dev)
{
	return 1;
}

/* Inspired by drivers/net/ethernet/dlink/sundance.c:1702
 * Declare each description string in struct.name[] to get fixed sized buffer
 * and compile time checking for strings longer than ETH_GSTRING_LEN.
 */
static const struct {
	const char name[ETH_GSTRING_LEN];
} batadv_counters_strings[] = {
	{ "tx" },
	{ "tx_bytes" },
	{ "tx_dropped" },
	{ "rx" },
	{ "rx_bytes" },
	{ "forward" },
	{ "forward_bytes" },
	{ "mgmt_tx" },
	{ "mgmt_tx_bytes" },
	{ "mgmt_rx" },
	{ "mgmt_rx_bytes" },
	{ "frag_tx" },
	{ "frag_tx_bytes" },
	{ "frag_rx" },
	{ "frag_rx_bytes" },
	{ "frag_fwd" },
	{ "frag_fwd_bytes" },
	{ "tt_request_tx" },
	{ "tt_request_rx" },
	{ "tt_response_tx" },
	{ "tt_response_rx" },
	{ "tt_roam_adv_tx" },
	{ "tt_roam_adv_rx" },
#ifdef CONFIG_BATMAN_ADV_DAT
	{ "dat_get_tx" },
	{ "dat_get_rx" },
	{ "dat_put_tx" },
	{ "dat_put_rx" },
	{ "dat_cached_reply_tx" },
#endif
#ifdef CONFIG_BATMAN_ADV_NC
	{ "nc_code" },
	{ "nc_code_bytes" },
	{ "nc_recode" },
	{ "nc_recode_bytes" },
	{ "nc_buffer" },
	{ "nc_decode" },
	{ "nc_decode_bytes" },
	{ "nc_decode_failed" },
	{ "nc_sniffed" },
#endif
};

static void batadv_get_strings(struct net_device *dev, u32 stringset, u8 *data)
{
	if (stringset == ETH_SS_STATS)
		memcpy(data, batadv_counters_strings,
		       sizeof(batadv_counters_strings));
}

static void batadv_get_ethtool_stats(struct net_device *dev,
				     struct ethtool_stats *stats, u64 *data)
{
	struct batadv_priv *bat_priv = netdev_priv(dev);
	int i;

	for (i = 0; i < BATADV_CNT_NUM; i++)
		data[i] = batadv_sum_counter(bat_priv, i);
}

static int batadv_get_sset_count(struct net_device *dev, int stringset)
{
	if (stringset == ETH_SS_STATS)
		return BATADV_CNT_NUM;

	return -EOPNOTSUPP;
}