text: // SPDX-License-Identifier: GPL-2.0
  /* Copyright (C) B.A.T.M.A.N. contributors:
   *
   * Marek Lindner, Simon Wunderlich
   */
  
  #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/cpumask.h>
  #include <linux/errno.h>
  #include <linux/etherdevice.h>
  #include <linux/ethtool.h>
  #include <linux/gfp.h>
  #include <linux/if_ether.h>
  #include <linux/if_vlan.h>
  #include <linux/jiffies.h>
  #include <linux/kernel.h>
  #include <linux/kref.h>
  #include <linux/list.h>
  #include <linux/lockdep.h>
  #include <linux/netdevice.h>
  #include <linux/netlink.h>
  #include <linux/percpu.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 <net/net_namespace.h>
  #include <net/netlink.h>
  #include <uapi/linux/batadv_packet.h>
  #include <uapi/linux/batman_adv.h>
  
  #include "bat_algo.h"
  #include "bridge_loop_avoidance.h"
  #include "distributed-arp-table.h"
  #include "gateway_client.h"
  #include "hard-interface.h"
  #include "multicast.h"
  #include "network-coding.h"
  #include "originator.h"
  #include "send.h"
  #include "translation-table.h"
  
  /**
   * batadv_skb_head_push() - Increase header size and move (push) head pointer
   * @skb: packet buffer which should be modified
   * @len: number of bytes to add
   *
   * Return: 0 on success or negative error number in case of failure
   */
  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;
  }
  
  /**
   * batadv_sum_counter() - Sum the cpu-local counters for index 'idx'
   * @bat_priv: the bat priv with all the soft interface information
   * @idx: index of counter to sum up
   *
   * Return: sum of all cpu-local counters
   */
  static u64 batadv_sum_counter(struct batadv_priv *bat_priv,  size_t idx)
  {
  	u64 *counters, sum = 0;
  	int cpu;
  
  	for_each_possible_cpu(cpu) {
  		counters = per_cpu_ptr(bat_priv->bat_counters, cpu);
  		sum += counters[idx];
  	}
  
  	return sum;
  }
  
  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 = &dev->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 netdev_tx_t 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;
  	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 = 0;
  	bool do_bcast = false, client_added;
  	unsigned short vid;
  	u32 seqno;
  	int gw_mode;
  	enum batadv_forw_mode forw_mode = BATADV_FORW_SINGLE;
  	struct batadv_orig_node *mcast_single_orig = NULL;
  	int network_offset = ETH_HLEN;
  	__be16 proto;
  
  	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
  		goto dropped;
  
  	/* reset control block to avoid left overs from previous users */
  	memset(skb->cb, 0, sizeof(struct batadv_skb_cb));
  
  	netif_trans_update(soft_iface);
  	vid = batadv_get_vid(skb, 0);
  
  	skb_reset_mac_header(skb);
  	ethhdr = eth_hdr(skb);
  
  	proto = ethhdr->h_proto;
  
  	switch (ntohs(proto)) {
  	case ETH_P_8021Q:
  		if (!pskb_may_pull(skb, sizeof(*vhdr)))
  			goto dropped;
  		vhdr = vlan_eth_hdr(skb);
  		proto = vhdr->h_vlan_encapsulated_proto;
  
  		/* drop batman-in-batman packets to prevent loops */
  		if (proto != htons(ETH_P_BATMAN)) {
  			network_offset += VLAN_HLEN;
  			break;
  		}
  
  		fallthrough;
  	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) &&
  	    !batadv_bla_is_loopdetect_mac(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;
  	}
  
  	/* Snoop address candidates from DHCPACKs for early DAT filling */
  	batadv_dat_snoop_outgoing_dhcp_ack(bat_priv, skb, proto, vid);
  
  	/* 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 ||
  			    forw_mode == BATADV_FORW_SOME)
  				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 - 1;
  
  		/* 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_send_bcast_packet(bat_priv, skb, brd_delay, true);
  	/* 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_mcast_forw_send_orig(bat_priv, skb, vid,
  							  mcast_single_orig);
  		} else if (forw_mode == BATADV_FORW_SOME) {
  			ret = batadv_mcast_forw_send(bat_priv, skb, 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_SUCCESS)
  			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:
  	batadv_orig_node_put(mcast_single_orig);
  	batadv_hardif_put(primary_if);
  	return NETDEV_TX_OK;
  }
  
  /**
   * batadv_interface_rx() - receive ethernet frame on local batman-adv interface
   * @soft_iface: local interface which will receive the ethernet frame
   * @skb: ethernet frame for @soft_iface
   * @hdr_size: size of already parsed batman-adv header
   * @orig_node: originator from which the batman-adv packet was sent
   *
   * Sends an ethernet frame to the receive path of the local @soft_iface.
   * skb->data has still point to the batman-adv header with the size @hdr_size.
   * The caller has to have parsed this header already and made sure that at least
   * @hdr_size bytes are still available for pull in @skb.
   *
   * The packet may still get dropped. This can happen when the encapsulated
   * ethernet frame is invalid or contains again an batman-adv packet. Also
   * unicast packets will be dropped directly when it was sent between two
   * isolated clients.
   */
  void batadv_interface_rx(struct net_device *soft_iface,
  			 struct sk_buff *skb, 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);
  	struct vlan_ethhdr *vhdr;
  	struct ethhdr *ethhdr;
  	unsigned short vid;
  	int packet_type;
  
  	batadv_bcast_packet = (struct batadv_bcast_packet *)skb->data;
  	packet_type = batadv_bcast_packet->packet_type;
  
  	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_ct(skb);
  
  	if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
  		goto dropped;
  
  	vid = batadv_get_vid(skb, 0);
  	ethhdr = eth_hdr(skb);
  
  	switch (ntohs(ethhdr->h_proto)) {
  	case ETH_P_8021Q:
  		if (!pskb_may_pull(skb, VLAN_ETH_HLEN))
  			goto dropped;
  
  		vhdr = (struct vlan_ethhdr *)skb->data;
  
  		/* drop batman-in-batman packets to prevent loops */
  		if (vhdr->h_vlan_encapsulated_proto != htons(ETH_P_BATMAN))
  			break;
  
  		fallthrough;
  	case ETH_P_BATMAN:
  		goto dropped;
  	}
  
  	/* skb->dev & skb->pkt_type are set here */
  	skb->protocol = eth_type_trans(skb, soft_iface);
  	skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
  
  	batadv_inc_counter(bat_priv, BATADV_CNT_RX);
  	batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
  			   skb->len + ETH_HLEN);
  
  	/* 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, packet_type))
  		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_release() - release vlan from lists and queue for free
   *  after rcu grace period
   * @ref: kref pointer of the vlan object
   */
  void batadv_softif_vlan_release(struct kref *ref)
  {
  	struct batadv_softif_vlan *vlan;
  
  	vlan = container_of(ref, struct batadv_softif_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
   *
   * Return: 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 (!kref_get_unless_zero(&vlan_tmp->refcount))
  			continue;
  
  		vlan = vlan_tmp;
  		break;
  	}
  	rcu_read_unlock();
  
  	return vlan;
  }
  
  /**
   * batadv_softif_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
   *
   * Return: 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;
  
  	spin_lock_bh(&bat_priv->softif_vlan_list_lock);
  
  	vlan = batadv_softif_vlan_get(bat_priv, vid);
  	if (vlan) {
  		batadv_softif_vlan_put(vlan);
  		spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
  		return -EEXIST;
  	}
  
  	vlan = kzalloc(sizeof(*vlan), GFP_ATOMIC);
  	if (!vlan) {
  		spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
  		return -ENOMEM;
  	}
  
  	vlan->bat_priv = bat_priv;
  	vlan->vid = vid;
  	kref_init(&vlan->refcount);
  
  	atomic_set(&vlan->ap_isolation, 0);
  
  	kref_get(&vlan->refcount);
  	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);
  
  	/* don't return reference to new softif_vlan */
  	batadv_softif_vlan_put(vlan);
  
  	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_softif_vlan_put(vlan);
  }
  
  /**
   * batadv_interface_add_vid() - ndo_add_vid API implementation
   * @dev: the netdev of the mesh interface
   * @proto: protocol of the vlan id
   * @vid: identifier of the new vlan
   *
   * Set up all the internal structures for handling the new vlan on top of the
   * mesh interface
   *
   * Return: 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;
  
  	/* 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);
  
  	/* 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
   * @proto: protocol of the vlan id
   * @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
   *
   * Return: 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_put(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_init_late() - late stage initialization of soft interface
   * @dev: registered network device to modify
   *
   * Return: 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;
  
  	/* 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
  	atomic_set(&bat_priv->multicast_mode, 1);
  	atomic_set(&bat_priv->multicast_fanout, 16);
  	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.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
  	atomic_set(&bat_priv->tp_num, 0);
  
  	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;
  
  	batadv_nc_init_bat_priv(bat_priv);
  
  	if (!bat_priv->algo_ops) {
  		ret = batadv_algo_select(bat_priv, batadv_routing_algo);
  		if (ret < 0)
  			goto free_bat_counters;
  	}
  
  	ret = batadv_mesh_init(dev);
  	if (ret < 0)
  		goto free_bat_counters;
  
  	return 0;
  
  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
   * @extack: extended ACK report struct
   *
   * Return: 0 if successful or error otherwise.
   */
  static int batadv_softif_slave_add(struct net_device *dev,
  				   struct net_device *slave_dev,
  				   struct netlink_ext_ack *extack)
  {
  	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);
  
  out:
  	batadv_hardif_put(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);
  	ret = 0;
  
  out:
  	batadv_hardif_put(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,
  };
  
  static void batadv_get_drvinfo(struct net_device *dev,
  			       struct ethtool_drvinfo *info)
  {
  	strscpy(info->driver, "B.A.T.M.A.N. advanced", sizeof(info->driver));
  	strscpy(info->version, BATADV_SOURCE_VERSION, sizeof(info->version));
  	strscpy(info->fw_version, "N/A", sizeof(info->fw_version));
  	strscpy(info->bus_info, "batman", sizeof(info->bus_info));
  }
  
  /* 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;
  }
  
  static const struct ethtool_ops batadv_ethtool_ops = {
  	.get_drvinfo = batadv_get_drvinfo,
  	.get_link = ethtool_op_get_link,
  	.get_strings = batadv_get_strings,
  	.get_ethtool_stats = batadv_get_ethtool_stats,
  	.get_sset_count = batadv_get_sset_count,
  };
  
  /**
   * batadv_softif_free() - Deconstructor of batadv_soft_interface
   * @dev: Device to cleanup and remove
   */
  static void batadv_softif_free(struct net_device *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();
  }
  
  /**
   * 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)
  {
  	ether_setup(dev);
  
  	dev->netdev_ops = &batadv_netdev_ops;
  	dev->needs_free_netdev = true;
  	dev->priv_destructor = batadv_softif_free;
  	dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_NETNS_LOCAL;
  	dev->features |= NETIF_F_LLTX;
  	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;
  }
  
  /**
   * batadv_softif_validate() - validate configuration of new batadv link
   * @tb: IFLA_INFO_DATA netlink attributes
   * @data: enum batadv_ifla_attrs attributes
   * @extack: extended ACK report struct
   *
   * Return: 0 if successful or error otherwise.
   */
  static int batadv_softif_validate(struct nlattr *tb[], struct nlattr *data[],
  				  struct netlink_ext_ack *extack)
  {
  	struct batadv_algo_ops *algo_ops;
  
  	if (!data)
  		return 0;
  
  	if (data[IFLA_BATADV_ALGO_NAME]) {
  		algo_ops = batadv_algo_get(nla_data(data[IFLA_BATADV_ALGO_NAME]));
  		if (!algo_ops)
  			return -EINVAL;
  	}
  
  	return 0;
  }
  
  /**
   * batadv_softif_newlink() - pre-initialize and register new batadv link
   * @src_net: the applicable net namespace
   * @dev: network device to register
   * @tb: IFLA_INFO_DATA netlink attributes
   * @data: enum batadv_ifla_attrs attributes
   * @extack: extended ACK report struct
   *
   * Return: 0 if successful or error otherwise.
   */
  static int batadv_softif_newlink(struct net *src_net, struct net_device *dev,
  				 struct nlattr *tb[], struct nlattr *data[],
  				 struct netlink_ext_ack *extack)
  {
  	struct batadv_priv *bat_priv = netdev_priv(dev);
  	const char *algo_name;
  	int err;
  
  	if (data && data[IFLA_BATADV_ALGO_NAME]) {
  		algo_name = nla_data(data[IFLA_BATADV_ALGO_NAME]);
  		err = batadv_algo_select(bat_priv, algo_name);
  		if (err)
  			return -EINVAL;
  	}
  
  	return register_netdevice(dev);
  }
  
  /**
   * 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_priv *bat_priv = netdev_priv(soft_iface);
  	struct batadv_hard_iface *hard_iface;
  	struct batadv_softif_vlan *vlan;
  
  	list_for_each_entry(hard_iface, &batadv_hardif_list, list) {
  		if (hard_iface->soft_iface == soft_iface)
  			batadv_hardif_disable_interface(hard_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_put(vlan);
  	}
  
  	unregister_netdevice_queue(soft_iface, head);
  }
  
  /**
   * batadv_softif_is_valid() - Check whether device is a batadv soft interface
   * @net_dev: device which should be checked
   *
   * Return: true when net_dev is a batman-adv interface, false otherwise
   */
  bool batadv_softif_is_valid(const struct net_device *net_dev)
  {
  	if (net_dev->netdev_ops->ndo_start_xmit == batadv_interface_tx)
  		return true;
  
  	return false;
  }
  
  static const struct nla_policy batadv_ifla_policy[IFLA_BATADV_MAX + 1] = {
  	[IFLA_BATADV_ALGO_NAME]	= { .type = NLA_NUL_STRING },
  };
  
  struct rtnl_link_ops batadv_link_ops __read_mostly = {
  	.kind		= "batadv",
  	.priv_size	= sizeof(struct batadv_priv),
  	.setup		= batadv_softif_init_early,
  	.maxtype	= IFLA_BATADV_MAX,
  	.policy		= batadv_ifla_policy,
  	.validate	= batadv_softif_validate,
  	.newlink	= batadv_softif_newlink,
  	.dellink	= batadv_softif_destroy_netlink,
  };
  