net/batman-adv/bat_v.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
 *
 * Linus Lüssing, Marek Lindner
 */

#include "bat_v.h"
#include "main.h"

#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/limits.h>
#include <linux/list.h>
#include <linux/minmax.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/genetlink.h>
#include <net/netlink.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

#include "bat_algo.h"
#include "bat_v_elp.h"
#include "bat_v_ogm.h"
#include "gateway_client.h"
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "netlink.h"
#include "originator.h"

/**
 * batadv_v_iface_activate() - finalise the activation of a hard interface
 * @hard_iface: interface to activate
 *
 * Reuse the currently selected primary interface to seed the ELP packet.
 * Immediately activate the interface.
 */
static void batadv_v_iface_activate(struct batadv_hard_iface *hard_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(hard_iface->mesh_iface);
	struct batadv_hard_iface *primary_if;

	primary_if = batadv_primary_if_get_selected(bat_priv);

	if (primary_if) {
		batadv_v_elp_iface_activate(primary_if, hard_iface);
		batadv_hardif_put(primary_if);
	}

	/* B.A.T.M.A.N. V does not use any queuing mechanism, therefore it can
	 * set the interface as ACTIVE right away, without any risk of race
	 * condition
	 */
	if (hard_iface->if_status == BATADV_IF_TO_BE_ACTIVATED)
		hard_iface->if_status = BATADV_IF_ACTIVE;
}

/**
 * batadv_v_iface_enable() - enable the B.A.T.M.A.N. V protocol on an
 *  interface
 * @hard_iface: interface to enable
 *
 * Enable the ELP and OGM components for @hard_iface. On error, the partially
 * enabled state is rolled back before returning.
 *
 * Return: 0 on success or negative error number in case of failure
 */
static int batadv_v_iface_enable(struct batadv_hard_iface *hard_iface)
{
	int ret;

	ret = batadv_v_elp_iface_enable(hard_iface);
	if (ret < 0)
		return ret;

	ret = batadv_v_ogm_iface_enable(hard_iface);
	if (ret < 0)
		batadv_v_elp_iface_disable(hard_iface);

	return ret;
}

/**
 * batadv_v_iface_disable() - disable the B.A.T.M.A.N. V protocol on an
 *  interface
 * @hard_iface: interface to disable
 */
static void batadv_v_iface_disable(struct batadv_hard_iface *hard_iface)
{
	batadv_v_ogm_iface_disable(hard_iface);
	batadv_v_elp_iface_disable(hard_iface);
}

/**
 * batadv_v_primary_iface_set() - apply primary interface state
 * @hard_iface: interface which just became the primary
 */
static void batadv_v_primary_iface_set(struct batadv_hard_iface *hard_iface)
{
	batadv_v_elp_primary_iface_set(hard_iface);
	batadv_v_ogm_primary_iface_set(hard_iface);
}

/**
 * batadv_v_iface_update_mac() - react to hard-interface MAC address change
 * @hard_iface: the modified interface
 *
 * If the modified interface is the primary one, update the originator
 * address in the ELP and OGM messages to reflect the new MAC address.
 */
static void batadv_v_iface_update_mac(struct batadv_hard_iface *hard_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(hard_iface->mesh_iface);
	struct batadv_hard_iface *primary_if;

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

	batadv_v_primary_iface_set(hard_iface);
out:
	batadv_hardif_put(primary_if);
}

/**
 * batadv_v_hardif_neigh_init() - initialise the B.A.T.M.A.N. V state of a
 *  hard interface neighbour
 * @hardif_neigh: hard interface neighbour to initialise
 */
static void
batadv_v_hardif_neigh_init(struct batadv_hardif_neigh_node *hardif_neigh)
{
	ewma_throughput_init(&hardif_neigh->bat_v.throughput);
}

/**
 * batadv_v_neigh_dump_neigh() - Dump a neighbour into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @hardif_neigh: Neighbour to dump
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_v_neigh_dump_neigh(struct sk_buff *msg, u32 portid, u32 seq,
			  struct batadv_hardif_neigh_node *hardif_neigh)
{
	unsigned int last_seen_msecs;
	u32 throughput;
	void *hdr;

	last_seen_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen);
	throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
	throughput = throughput * 100;

	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, NLM_F_MULTI,
			  BATADV_CMD_GET_NEIGHBORS);
	if (!hdr)
		return -ENOBUFS;

	if (nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
		    hardif_neigh->addr) ||
	    nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
			   hardif_neigh->if_incoming->net_dev->name) ||
	    nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
			hardif_neigh->if_incoming->net_dev->ifindex) ||
	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS,
			last_seen_msecs) ||
	    nla_put_u32(msg, BATADV_ATTR_THROUGHPUT, throughput))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

 nla_put_failure:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

/**
 * batadv_v_neigh_dump_hardif() - Dump the  neighbours of a hard interface into
 *  a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @hard_iface: The hard interface to be dumped
 * @idx_s: Entries to be skipped
 *
 * This function assumes the caller holds rcu_read_lock().
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_v_neigh_dump_hardif(struct sk_buff *msg, u32 portid, u32 seq,
			   struct batadv_priv *bat_priv,
			   struct batadv_hard_iface *hard_iface,
			   int *idx_s)
{
	struct batadv_hardif_neigh_node *hardif_neigh;
	int idx = 0;

	hlist_for_each_entry_rcu(hardif_neigh,
				 &hard_iface->neigh_list, list) {
		if (idx++ < *idx_s)
			continue;

		if (batadv_v_neigh_dump_neigh(msg, portid, seq, hardif_neigh)) {
			*idx_s = idx - 1;
			return -EMSGSIZE;
		}
	}

	*idx_s = 0;
	return 0;
}

/**
 * batadv_v_neigh_dump() - Dump the neighbours of a hard interface  into a
 *  message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 * @single_hardif: Limit dumping to this hard interface
 */
static void
batadv_v_neigh_dump(struct sk_buff *msg, struct netlink_callback *cb,
		    struct batadv_priv *bat_priv,
		    struct batadv_hard_iface *single_hardif)
{
	int portid = NETLINK_CB(cb->skb).portid;
	struct batadv_hard_iface *hard_iface;
	int i_hardif_s = cb->args[0];
	struct list_head *iter;
	int idx = cb->args[1];
	int i_hardif = 0;

	rcu_read_lock();
	if (single_hardif) {
		if (i_hardif_s == 0) {
			if (batadv_v_neigh_dump_hardif(msg, portid,
						       cb->nlh->nlmsg_seq,
						       bat_priv, single_hardif,
						       &idx) == 0)
				i_hardif++;
		}
	} else {
		netdev_for_each_lower_private_rcu(bat_priv->mesh_iface, hard_iface, iter) {
			if (i_hardif++ < i_hardif_s)
				continue;

			if (batadv_v_neigh_dump_hardif(msg, portid,
						       cb->nlh->nlmsg_seq,
						       bat_priv, hard_iface,
						       &idx)) {
				i_hardif--;
				break;
			}
		}
	}
	rcu_read_unlock();

	cb->args[0] = i_hardif;
	cb->args[1] = idx;
}

/**
 * batadv_v_orig_dump_subentry() - Dump an originator subentry into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @orig_node: Originator to dump
 * @neigh_node: Single hops neighbour
 * @best: Is the best originator
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_v_orig_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
			    struct batadv_priv *bat_priv,
			    struct batadv_hard_iface *if_outgoing,
			    struct batadv_orig_node *orig_node,
			    struct batadv_neigh_node *neigh_node,
			    bool best)
{
	struct batadv_neigh_ifinfo *n_ifinfo;
	unsigned int last_seen_msecs;
	u32 throughput;
	void *hdr;

	n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
	if (!n_ifinfo)
		return 0;

	throughput = n_ifinfo->bat_v.throughput * 100;

	batadv_neigh_ifinfo_put(n_ifinfo);

	last_seen_msecs = jiffies_to_msecs(jiffies - orig_node->last_seen);

	if (if_outgoing != BATADV_IF_DEFAULT &&
	    if_outgoing != neigh_node->if_incoming)
		return 0;

	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, NLM_F_MULTI,
			  BATADV_CMD_GET_ORIGINATORS);
	if (!hdr)
		return -ENOBUFS;

	if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN, orig_node->orig) ||
	    nla_put(msg, BATADV_ATTR_NEIGH_ADDRESS, ETH_ALEN,
		    neigh_node->addr) ||
	    nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
			   neigh_node->if_incoming->net_dev->name) ||
	    nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
			neigh_node->if_incoming->net_dev->ifindex) ||
	    nla_put_u32(msg, BATADV_ATTR_THROUGHPUT, throughput) ||
	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS,
			last_seen_msecs))
		goto nla_put_failure;

	if (best && nla_put_flag(msg, BATADV_ATTR_FLAG_BEST))
		goto nla_put_failure;

	genlmsg_end(msg, hdr);
	return 0;

 nla_put_failure:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

/**
 * batadv_v_orig_dump_entry() - Dump an originator entry into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @orig_node: Originator to dump
 * @sub_s: Number of sub entries to skip
 *
 * This function assumes the caller holds rcu_read_lock().
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_v_orig_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
			 struct batadv_priv *bat_priv,
			 struct batadv_hard_iface *if_outgoing,
			 struct batadv_orig_node *orig_node, int *sub_s)
{
	struct batadv_neigh_node *neigh_node_best;
	struct batadv_neigh_node *neigh_node;
	int sub = 0;
	bool best;

	neigh_node_best = batadv_orig_router_get(orig_node, if_outgoing);
	if (!neigh_node_best)
		goto out;

	hlist_for_each_entry_rcu(neigh_node, &orig_node->neigh_list, list) {
		if (sub++ < *sub_s)
			continue;

		best = (neigh_node == neigh_node_best);

		if (batadv_v_orig_dump_subentry(msg, portid, seq, bat_priv,
						if_outgoing, orig_node,
						neigh_node, best)) {
			batadv_neigh_node_put(neigh_node_best);

			*sub_s = sub - 1;
			return -EMSGSIZE;
		}
	}

 out:
	batadv_neigh_node_put(neigh_node_best);

	*sub_s = 0;
	return 0;
}

/**
 * batadv_v_orig_dump_bucket() - Dump an originator bucket into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @seq: Sequence number of netlink message
 * @bat_priv: The bat priv with all the mesh interface information
 * @if_outgoing: Limit dump to entries with this outgoing interface
 * @head: Bucket to be dumped
 * @idx_s: Number of entries to be skipped
 * @sub: Number of sub entries to be skipped
 *
 * Return: Error code, or 0 on success
 */
static int
batadv_v_orig_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
			  struct batadv_priv *bat_priv,
			  struct batadv_hard_iface *if_outgoing,
			  struct hlist_head *head, int *idx_s, int *sub)
{
	struct batadv_orig_node *orig_node;
	int idx = 0;

	rcu_read_lock();
	hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
		if (idx++ < *idx_s)
			continue;

		if (batadv_v_orig_dump_entry(msg, portid, seq, bat_priv,
					     if_outgoing, orig_node, sub)) {
			rcu_read_unlock();
			*idx_s = idx - 1;
			return -EMSGSIZE;
		}
	}
	rcu_read_unlock();

	*idx_s = 0;
	*sub = 0;
	return 0;
}

/**
 * batadv_v_orig_dump() - Dump the originators into a message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 * @if_outgoing: Limit dump to entries with this outgoing interface
 */
static void
batadv_v_orig_dump(struct sk_buff *msg, struct netlink_callback *cb,
		   struct batadv_priv *bat_priv,
		   struct batadv_hard_iface *if_outgoing)
{
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	int portid = NETLINK_CB(cb->skb).portid;
	int bucket = cb->args[0];
	struct hlist_head *head;
	int idx = cb->args[1];
	int sub = cb->args[2];

	while (bucket < hash->size) {
		head = &hash->table[bucket];

		if (batadv_v_orig_dump_bucket(msg, portid,
					      cb->nlh->nlmsg_seq,
					      bat_priv, if_outgoing, head, &idx,
					      &sub))
			break;

		bucket++;
	}

	cb->args[0] = bucket;
	cb->args[1] = idx;
	cb->args[2] = sub;
}

/**
 * batadv_v_neigh_cmp() - compare two B.A.T.M.A.N. V neighbours by throughput
 * @neigh1: first neighbour to compare
 * @if_outgoing1: outgoing interface to use for @neigh1
 * @neigh2: second neighbour to compare
 * @if_outgoing2: outgoing interface to use for @neigh2
 *
 * Return: a positive value if @neigh1 is better, a negative value if @neigh2
 *  is better and 0 if both have equal throughput
 */
static int batadv_v_neigh_cmp(struct batadv_neigh_node *neigh1,
			      struct batadv_hard_iface *if_outgoing1,
			      struct batadv_neigh_node *neigh2,
			      struct batadv_hard_iface *if_outgoing2)
{
	struct batadv_neigh_ifinfo *ifinfo1;
	struct batadv_neigh_ifinfo *ifinfo2;
	int ret = 0;

	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
	if (!ifinfo1)
		goto err_ifinfo1;

	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
	if (!ifinfo2)
		goto err_ifinfo2;

	ret = ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;

	batadv_neigh_ifinfo_put(ifinfo2);
err_ifinfo2:
	batadv_neigh_ifinfo_put(ifinfo1);
err_ifinfo1:
	return ret;
}

/**
 * batadv_v_neigh_is_sob() - check whether two B.A.T.M.A.N. V neighbours have
 *  a similar or better throughput
 * @neigh1: first neighbour to compare
 * @if_outgoing1: outgoing interface to use for @neigh1
 * @neigh2: second neighbour to compare
 * @if_outgoing2: outgoing interface to use for @neigh2
 *
 * Return: true if the throughput of @neigh2 is at least 3/4 of the
 *  @neigh1 throughput
 */
static bool batadv_v_neigh_is_sob(struct batadv_neigh_node *neigh1,
				  struct batadv_hard_iface *if_outgoing1,
				  struct batadv_neigh_node *neigh2,
				  struct batadv_hard_iface *if_outgoing2)
{
	struct batadv_neigh_ifinfo *ifinfo1;
	struct batadv_neigh_ifinfo *ifinfo2;
	bool ret = false;
	u32 threshold;

	ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
	if (!ifinfo1)
		goto err_ifinfo1;

	ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
	if (!ifinfo2)
		goto err_ifinfo2;

	threshold = ifinfo1->bat_v.throughput / 4;
	threshold = ifinfo1->bat_v.throughput - threshold;

	ret = ifinfo2->bat_v.throughput > threshold;

	batadv_neigh_ifinfo_put(ifinfo2);
err_ifinfo2:
	batadv_neigh_ifinfo_put(ifinfo1);
err_ifinfo1:
	return ret;
}

/**
 * batadv_v_init_sel_class() - initialize GW selection class
 * @bat_priv: the bat priv with all the mesh interface information
 */
static void batadv_v_init_sel_class(struct batadv_priv *bat_priv)
{
	/* set default throughput difference threshold to 5Mbps */
	WRITE_ONCE(bat_priv->gw.sel_class, 50);
}

/**
 * batadv_v_gw_throughput_get() - retrieve the GW-bandwidth for a given GW
 * @gw_node: the GW to retrieve the metric for
 * @bw: the pointer where the metric will be stored. The metric is computed as
 *  the minimum between the GW advertised throughput and the path throughput to
 *  it in the mesh
 *
 * Return: 0 on success, -1 on failure
 */
static int batadv_v_gw_throughput_get(struct batadv_gw_node *gw_node, u32 *bw)
{
	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
	struct batadv_orig_node *orig_node;
	struct batadv_neigh_node *router;
	int ret = -1;

	orig_node = gw_node->orig_node;
	router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
	if (!router)
		goto out;

	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
	if (!router_ifinfo)
		goto out;

	/* the GW metric is computed as the minimum between the path throughput
	 * to reach the GW itself and the advertised bandwidth.
	 * This gives us an approximation of the effective throughput that the
	 * client can expect via this particular GW node
	 */
	*bw = router_ifinfo->bat_v.throughput;
	*bw = min_t(u32, *bw, gw_node->bandwidth_down);

	ret = 0;
out:
	batadv_neigh_node_put(router);
	batadv_neigh_ifinfo_put(router_ifinfo);

	return ret;
}

/**
 * batadv_v_gw_get_best_gw_node() - retrieve the best GW node
 * @bat_priv: the bat priv with all the mesh interface information
 *
 * Return: the GW node having the best GW-metric, NULL if no GW is known
 */
static struct batadv_gw_node *
batadv_v_gw_get_best_gw_node(struct batadv_priv *bat_priv)
{
	struct batadv_gw_node *curr_gw = NULL;
	struct batadv_gw_node *gw_node;
	u32 max_bw = 0;
	u32 bw;

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {
		if (!kref_get_unless_zero(&gw_node->refcount))
			continue;

		if (batadv_v_gw_throughput_get(gw_node, &bw) < 0)
			goto next;

		if (curr_gw && bw <= max_bw)
			goto next;

		batadv_gw_node_put(curr_gw);

		curr_gw = gw_node;
		kref_get(&curr_gw->refcount);
		max_bw = bw;

next:
		batadv_gw_node_put(gw_node);
	}
	rcu_read_unlock();

	return curr_gw;
}

/**
 * batadv_v_gw_is_eligible() - check if an originator would be selected as GW
 * @bat_priv: the bat priv with all the mesh interface information
 * @curr_gw_orig: originator representing the currently selected GW
 * @orig_node: the originator representing the new candidate
 *
 * Return: true if orig_node can be selected as current GW, false otherwise
 */
static bool batadv_v_gw_is_eligible(struct batadv_priv *bat_priv,
				    struct batadv_orig_node *curr_gw_orig,
				    struct batadv_orig_node *orig_node)
{
	struct batadv_gw_node *orig_gw = NULL;
	struct batadv_gw_node *curr_gw;
	u32 orig_throughput;
	u32 gw_throughput;
	bool ret = false;
	u32 threshold;

	threshold = READ_ONCE(bat_priv->gw.sel_class);

	curr_gw = batadv_gw_node_get(bat_priv, curr_gw_orig);
	if (!curr_gw) {
		ret = true;
		goto out;
	}

	if (batadv_v_gw_throughput_get(curr_gw, &gw_throughput) < 0) {
		ret = true;
		goto out;
	}

	orig_gw = batadv_gw_node_get(bat_priv, orig_node);
	if (!orig_gw)
		goto out;

	if (batadv_v_gw_throughput_get(orig_gw, &orig_throughput) < 0)
		goto out;

	if (orig_throughput < gw_throughput)
		goto out;

	if ((orig_throughput - gw_throughput) < threshold)
		goto out;

	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
		   "Restarting gateway selection: better gateway found (throughput curr: %u, throughput new: %u)\n",
		   gw_throughput, orig_throughput);

	ret = true;
out:
	batadv_gw_node_put(curr_gw);
	batadv_gw_node_put(orig_gw);

	return ret;
}

/**
 * batadv_v_gw_dump_entry() - Dump a gateway into a message
 * @msg: Netlink message to dump into
 * @portid: Port making netlink request
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 * @gw_node: Gateway to be dumped
 *
 * Return: Error code, or 0 on success
 */
static int batadv_v_gw_dump_entry(struct sk_buff *msg, u32 portid,
				  struct netlink_callback *cb,
				  struct batadv_priv *bat_priv,
				  struct batadv_gw_node *gw_node)
{
	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
	struct batadv_gw_node *curr_gw = NULL;
	struct batadv_neigh_node *router;
	int ret = 0;
	void *hdr;

	router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);
	if (!router)
		goto out;

	router_ifinfo = batadv_neigh_ifinfo_get(router, BATADV_IF_DEFAULT);
	if (!router_ifinfo)
		goto out;

	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

	hdr = genlmsg_put(msg, portid, cb->nlh->nlmsg_seq,
			  &batadv_netlink_family, NLM_F_MULTI,
			  BATADV_CMD_GET_GATEWAYS);
	if (!hdr) {
		ret = -ENOBUFS;
		goto out;
	}

	genl_dump_check_consistent(cb, hdr);

	ret = -EMSGSIZE;

	if (curr_gw == gw_node) {
		if (nla_put_flag(msg, BATADV_ATTR_FLAG_BEST)) {
			genlmsg_cancel(msg, hdr);
			goto out;
		}
	}

	if (nla_put(msg, BATADV_ATTR_ORIG_ADDRESS, ETH_ALEN,
		    gw_node->orig_node->orig)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put_u32(msg, BATADV_ATTR_THROUGHPUT,
			router_ifinfo->bat_v.throughput)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put(msg, BATADV_ATTR_ROUTER, ETH_ALEN, router->addr)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
			   router->if_incoming->net_dev->name)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put_u32(msg, BATADV_ATTR_HARD_IFINDEX,
			router->if_incoming->net_dev->ifindex)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_DOWN,
			gw_node->bandwidth_down)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	if (nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_UP, gw_node->bandwidth_up)) {
		genlmsg_cancel(msg, hdr);
		goto out;
	}

	genlmsg_end(msg, hdr);
	ret = 0;

out:
	batadv_gw_node_put(curr_gw);
	batadv_neigh_ifinfo_put(router_ifinfo);
	batadv_neigh_node_put(router);
	return ret;
}

/**
 * batadv_v_gw_dump() - Dump gateways into a message
 * @msg: Netlink message to dump into
 * @cb: Control block containing additional options
 * @bat_priv: The bat priv with all the mesh interface information
 */
static void batadv_v_gw_dump(struct sk_buff *msg, struct netlink_callback *cb,
			     struct batadv_priv *bat_priv)
{
	int portid = NETLINK_CB(cb->skb).portid;
	struct batadv_gw_node *gw_node;
	int idx_skip = cb->args[0];
	int idx = 0;

	spin_lock_bh(&bat_priv->gw.list_lock);
	cb->seq = bat_priv->gw.generation << 1 | 1;

	hlist_for_each_entry(gw_node, &bat_priv->gw.gateway_list, list) {
		if (idx++ < idx_skip)
			continue;

		if (batadv_v_gw_dump_entry(msg, portid, cb, bat_priv,
					   gw_node)) {
			idx_skip = idx - 1;
			goto unlock;
		}
	}

	idx_skip = idx;
unlock:
	spin_unlock_bh(&bat_priv->gw.list_lock);

	cb->args[0] = idx_skip;
}

static struct batadv_algo_ops batadv_batman_v __read_mostly = {
	.name = "BATMAN_V",
	.iface = {
		.activate = batadv_v_iface_activate,
		.enable = batadv_v_iface_enable,
		.disable = batadv_v_iface_disable,
		.update_mac = batadv_v_iface_update_mac,
		.primary_set = batadv_v_primary_iface_set,
	},
	.neigh = {
		.hardif_init = batadv_v_hardif_neigh_init,
		.cmp = batadv_v_neigh_cmp,
		.is_similar_or_better = batadv_v_neigh_is_sob,
		.dump = batadv_v_neigh_dump,
	},
	.orig = {
		.dump = batadv_v_orig_dump,
	},
	.gw = {
		.init_sel_class = batadv_v_init_sel_class,
		.sel_class_max = U32_MAX,
		.get_best_gw_node = batadv_v_gw_get_best_gw_node,
		.is_eligible = batadv_v_gw_is_eligible,
		.dump = batadv_v_gw_dump,
	},
};

/**
 * batadv_v_hardif_init() - initialize the algorithm specific fields in the
 *  hard-interface object
 * @hard_iface: the hard-interface to initialize
 */
void batadv_v_hardif_init(struct batadv_hard_iface *hard_iface)
{
	/* enable link throughput auto-detection by setting the throughput
	 * override to zero
	 */
	WRITE_ONCE(hard_iface->bat_v.throughput_override, 0);
	WRITE_ONCE(hard_iface->bat_v.elp_interval, 500);

	hard_iface->bat_v.aggr_len = 0;
	skb_queue_head_init(&hard_iface->bat_v.aggr_list);
	hard_iface->bat_v.aggr_list_enabled = false;
	INIT_DELAYED_WORK(&hard_iface->bat_v.aggr_wq,
			  batadv_v_ogm_aggr_work);
	/* make sure it doesn't run until interface gets enabled */
	disable_delayed_work(&hard_iface->bat_v.aggr_wq);
}

/**
 * batadv_v_mesh_init() - initialize the B.A.T.M.A.N. V private resources for a
 *  mesh
 * @bat_priv: the object representing the mesh interface to initialise
 *
 * Return: 0 on success or a negative error code otherwise
 */
int batadv_v_mesh_init(struct batadv_priv *bat_priv)
{
	int ret = 0;

	ret = batadv_v_ogm_init(bat_priv);
	if (ret < 0)
		return ret;

	return 0;
}

/**
 * batadv_v_mesh_free() - free the B.A.T.M.A.N. V private resources for a mesh
 * @bat_priv: the object representing the mesh interface to free
 */
void batadv_v_mesh_free(struct batadv_priv *bat_priv)
{
	batadv_v_ogm_free(bat_priv);
}

/**
 * batadv_v_init() - B.A.T.M.A.N. V initialization function
 *
 * Description: Takes care of initializing all the subcomponents.
 * It is invoked upon module load only.
 *
 * Return: 0 on success or a negative error code otherwise
 */
int __init batadv_v_init(void)
{
	int ret;

	/* B.A.T.M.A.N. V echo location protocol packet  */
	ret = batadv_recv_handler_register(BATADV_ELP,
					   batadv_v_elp_packet_recv);
	if (ret < 0)
		return ret;

	ret = batadv_recv_handler_register(BATADV_OGM2,
					   batadv_v_ogm_packet_recv);
	if (ret < 0)
		goto elp_unregister;

	ret = batadv_algo_register(&batadv_batman_v);
	if (ret < 0)
		goto ogm_unregister;

	return ret;

ogm_unregister:
	batadv_recv_handler_unregister(BATADV_OGM2);

elp_unregister:
	batadv_recv_handler_unregister(BATADV_ELP);

	return ret;
}

/**
 * batadv_v_deinit() - B.A.T.M.A.N. V deinitialization function
 */
void batadv_v_deinit(void)
{
	batadv_recv_handler_unregister(BATADV_OGM2);
	batadv_recv_handler_unregister(BATADV_ELP);
}