1 files changed, 790 insertions, 97 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 19b0abd6c640..f00f666e2ccd 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -35,6 +35,7 @@
 #include <linux/list.h>
 #include <linux/lockdep.h>
 #include <linux/netdevice.h>
+#include <linux/netlink.h>
 #include <linux/pkt_sched.h>
 #include <linux/printk.h>
 #include <linux/random.h>
@@ -48,12 +49,17 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
+#include <net/genetlink.h>
+#include <net/netlink.h>
+#include <uapi/linux/batman_adv.h>
 
 #include "bat_algo.h"
 #include "bitarray.h"
+#include "gateway_client.h"
 #include "hard-interface.h"
 #include "hash.h"
 #include "log.h"
+#include "netlink.h"
 #include "network-coding.h"
 #include "originator.h"
 #include "packet.h"
@@ -318,17 +324,18 @@ batadv_iv_ogm_orig_get(struct batadv_priv *bat_priv, const u8 *addr)
 	if (!orig_node->bat_iv.bcast_own_sum)
 		goto free_orig_node;
 
+	kref_get(&orig_node->refcount);
 	hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
 				     batadv_choose_orig, orig_node,
 				     &orig_node->hash_entry);
 	if (hash_added != 0)
-		goto free_orig_node;
+		goto free_orig_node_hash;
 
 	return orig_node;
 
-free_orig_node:
-	/* free twice, as batadv_orig_node_new sets refcount to 2 */
+free_orig_node_hash:
 	batadv_orig_node_put(orig_node);
+free_orig_node:
 	batadv_orig_node_put(orig_node);
 
 	return NULL;
@@ -528,36 +535,25 @@ static void batadv_iv_ogm_send_to_if(struct batadv_forw_packet *forw_packet,
 static void batadv_iv_ogm_emit(struct batadv_forw_packet *forw_packet)
 {
 	struct net_device *soft_iface;
-	struct batadv_priv *bat_priv;
-	struct batadv_hard_iface *primary_if = NULL;
 
 	if (!forw_packet->if_incoming) {
 		pr_err("Error - can't forward packet: incoming iface not specified\n");
-		goto out;
+		return;
 	}
 
 	soft_iface = forw_packet->if_incoming->soft_iface;
-	bat_priv = netdev_priv(soft_iface);
 
 	if (WARN_ON(!forw_packet->if_outgoing))
-		goto out;
+		return;
 
 	if (WARN_ON(forw_packet->if_outgoing->soft_iface != soft_iface))
-		goto out;
+		return;
 
 	if (forw_packet->if_incoming->if_status != BATADV_IF_ACTIVE)
-		goto out;
-
-	primary_if = batadv_primary_if_get_selected(bat_priv);
-	if (!primary_if)
-		goto out;
+		return;
 
 	/* only for one specific outgoing interface */
 	batadv_iv_ogm_send_to_if(forw_packet, forw_packet->if_outgoing);
-
-out:
-	if (primary_if)
-		batadv_hardif_put(primary_if);
 }
 
 /**
@@ -685,19 +681,12 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 	struct batadv_forw_packet *forw_packet_aggr;
 	unsigned char *skb_buff;
 	unsigned int skb_size;
+	atomic_t *queue_left = own_packet ? NULL : &bat_priv->batman_queue_left;
 
-	/* own packet should always be scheduled */
-	if (!own_packet) {
-		if (!batadv_atomic_dec_not_zero(&bat_priv->batman_queue_left)) {
-			batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
-				   "batman packet queue full\n");
-			return;
-		}
-	}
-
-	forw_packet_aggr = kmalloc(sizeof(*forw_packet_aggr), GFP_ATOMIC);
+	forw_packet_aggr = batadv_forw_packet_alloc(if_incoming, if_outgoing,
+						    queue_left, bat_priv);
 	if (!forw_packet_aggr)
-		goto out_nomem;
+		return;
 
 	if (atomic_read(&bat_priv->aggregated_ogms) &&
 	    packet_len < BATADV_MAX_AGGREGATION_BYTES)
@@ -708,8 +697,11 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 	skb_size += ETH_HLEN;
 
 	forw_packet_aggr->skb = netdev_alloc_skb_ip_align(NULL, skb_size);
-	if (!forw_packet_aggr->skb)
-		goto out_free_forw_packet;
+	if (!forw_packet_aggr->skb) {
+		batadv_forw_packet_free(forw_packet_aggr, true);
+		return;
+	}
+
 	forw_packet_aggr->skb->priority = TC_PRIO_CONTROL;
 	skb_reserve(forw_packet_aggr->skb, ETH_HLEN);
 
@@ -717,12 +709,7 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 	forw_packet_aggr->packet_len = packet_len;
 	memcpy(skb_buff, packet_buff, packet_len);
 
-	kref_get(&if_incoming->refcount);
-	kref_get(&if_outgoing->refcount);
 	forw_packet_aggr->own = own_packet;
-	forw_packet_aggr->if_incoming = if_incoming;
-	forw_packet_aggr->if_outgoing = if_outgoing;
-	forw_packet_aggr->num_packets = 0;
 	forw_packet_aggr->direct_link_flags = BATADV_NO_FLAGS;
 	forw_packet_aggr->send_time = send_time;
 
@@ -730,24 +717,10 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 	if (direct_link)
 		forw_packet_aggr->direct_link_flags |= 1;
 
-	/* add new packet to packet list */
-	spin_lock_bh(&bat_priv->forw_bat_list_lock);
-	hlist_add_head(&forw_packet_aggr->list, &bat_priv->forw_bat_list);
-	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
-
-	/* start timer for this packet */
 	INIT_DELAYED_WORK(&forw_packet_aggr->delayed_work,
 			  batadv_iv_send_outstanding_bat_ogm_packet);
-	queue_delayed_work(batadv_event_workqueue,
-			   &forw_packet_aggr->delayed_work,
-			   send_time - jiffies);
-
-	return;
-out_free_forw_packet:
-	kfree(forw_packet_aggr);
-out_nomem:
-	if (!own_packet)
-		atomic_inc(&bat_priv->batman_queue_left);
+
+	batadv_forw_packet_ogmv1_queue(bat_priv, forw_packet_aggr, send_time);
 }
 
 /* aggregate a new packet into the existing ogm packet */
@@ -1292,7 +1265,7 @@ static bool batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node,
 	 */
 	tq_iface_penalty = BATADV_TQ_MAX_VALUE;
 	if (if_outgoing && (if_incoming == if_outgoing) &&
-	    batadv_is_wifi_netdev(if_outgoing->net_dev))
+	    batadv_is_wifi_hardif(if_outgoing))
 		tq_iface_penalty = batadv_hop_penalty(BATADV_TQ_MAX_VALUE,
 						      bat_priv);
 
@@ -1631,7 +1604,7 @@ out:
 	if (hardif_neigh)
 		batadv_hardif_neigh_put(hardif_neigh);
 
-	kfree_skb(skb_priv);
+	consume_skb(skb_priv);
 }
 
 /**
@@ -1803,17 +1776,17 @@ static void batadv_iv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 	struct delayed_work *delayed_work;
 	struct batadv_forw_packet *forw_packet;
 	struct batadv_priv *bat_priv;
+	bool dropped = false;
 
 	delayed_work = to_delayed_work(work);
 	forw_packet = container_of(delayed_work, struct batadv_forw_packet,
 				   delayed_work);
 	bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
-	spin_lock_bh(&bat_priv->forw_bat_list_lock);
-	hlist_del(&forw_packet->list);
-	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
 
-	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
+	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
+		dropped = true;
 		goto out;
+	}
 
 	batadv_iv_ogm_emit(forw_packet);
 
@@ -1830,11 +1803,10 @@ static void batadv_iv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 		batadv_iv_ogm_schedule(forw_packet->if_incoming);
 
 out:
-	/* don't count own packet */
-	if (!forw_packet->own)
-		atomic_inc(&bat_priv->batman_queue_left);
-
-	batadv_forw_packet_free(forw_packet);
+	/* do we get something for free()? */
+	if (batadv_forw_packet_steal(forw_packet,
+				     &bat_priv->forw_bat_list_lock))
+		batadv_forw_packet_free(forw_packet, dropped);
 }
 
 static int batadv_iv_ogm_receive(struct sk_buff *skb,
@@ -1844,17 +1816,18 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 	struct batadv_ogm_packet *ogm_packet;
 	u8 *packet_pos;
 	int ogm_offset;
-	bool ret;
+	bool res;
+	int ret = NET_RX_DROP;
 
-	ret = batadv_check_management_packet(skb, if_incoming, BATADV_OGM_HLEN);
-	if (!ret)
-		return NET_RX_DROP;
+	res = batadv_check_management_packet(skb, if_incoming, BATADV_OGM_HLEN);
+	if (!res)
+		goto free_skb;
 
 	/* did we receive a B.A.T.M.A.N. IV OGM packet on an interface
 	 * that does not have B.A.T.M.A.N. IV enabled ?
 	 */
 	if (bat_priv->algo_ops->iface.enable != batadv_iv_ogm_iface_enable)
-		return NET_RX_DROP;
+		goto free_skb;
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 	batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
@@ -1875,10 +1848,18 @@ static int batadv_iv_ogm_receive(struct sk_buff *skb,
 		ogm_packet = (struct batadv_ogm_packet *)packet_pos;
 	}
 
-	kfree_skb(skb);
-	return NET_RX_SUCCESS;
+	ret = NET_RX_SUCCESS;
+
+free_skb:
+	if (ret == NET_RX_SUCCESS)
+		consume_skb(skb);
+	else
+		kfree_skb(skb);
+
+	return ret;
 }
 
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
 /**
  * batadv_iv_ogm_orig_print_neigh - print neighbors for the originator table
  * @orig_node: the orig_node for which the neighbors are printed
@@ -1976,8 +1957,239 @@ next:
 	if (batman_count == 0)
 		seq_puts(seq, "No batman nodes in range ...\n");
 }
+#endif
+
+/**
+ * batadv_iv_ogm_neigh_get_tq_avg - Get the TQ average for a neighbour on a
+ *  given outgoing interface.
+ * @neigh_node: Neighbour of interest
+ * @if_outgoing: Outgoing interface of interest
+ * @tq_avg: Pointer of where to store the TQ average
+ *
+ * Return: False if no average TQ available, otherwise true.
+ */
+static bool
+batadv_iv_ogm_neigh_get_tq_avg(struct batadv_neigh_node *neigh_node,
+			       struct batadv_hard_iface *if_outgoing,
+			       u8 *tq_avg)
+{
+	struct batadv_neigh_ifinfo *n_ifinfo;
+
+	n_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
+	if (!n_ifinfo)
+		return false;
+
+	*tq_avg = n_ifinfo->bat_iv.tq_avg;
+	batadv_neigh_ifinfo_put(n_ifinfo);
+
+	return true;
+}
+
+/**
+ * batadv_iv_ogm_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 soft 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_iv_ogm_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)
+{
+	void *hdr;
+	u8 tq_avg;
+	unsigned int last_seen_msecs;
+
+	last_seen_msecs = jiffies_to_msecs(jiffies - orig_node->last_seen);
+
+	if (!batadv_iv_ogm_neigh_get_tq_avg(neigh_node, if_outgoing, &tq_avg))
+		return 0;
+
+	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_u32(msg, BATADV_ATTR_HARD_IFINDEX,
+			neigh_node->if_incoming->net_dev->ifindex) ||
+	    nla_put_u8(msg, BATADV_ATTR_TQ, tq_avg) ||
+	    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_iv_ogm_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 soft 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_iv_ogm_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;
+	u8 tq_avg_best;
+
+	neigh_node_best = batadv_orig_router_get(orig_node, if_outgoing);
+	if (!neigh_node_best)
+		goto out;
+
+	if (!batadv_iv_ogm_neigh_get_tq_avg(neigh_node_best, if_outgoing,
+					    &tq_avg_best))
+		goto out;
+
+	if (tq_avg_best == 0)
+		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_iv_ogm_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:
+	if (neigh_node_best)
+		batadv_neigh_node_put(neigh_node_best);
+
+	*sub_s = 0;
+	return 0;
+}
+
+/**
+ * batadv_iv_ogm_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 soft 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_iv_ogm_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_iv_ogm_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_iv_ogm_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 soft interface information
+ * @if_outgoing: Limit dump to entries with this outgoing interface
+ */
+static void
+batadv_iv_ogm_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;
+	struct hlist_head *head;
+	int bucket = cb->args[0];
+	int idx = cb->args[1];
+	int sub = cb->args[2];
+	int portid = NETLINK_CB(cb->skb).portid;
+
+	while (bucket < hash->size) {
+		head = &hash->table[bucket];
+
+		if (batadv_iv_ogm_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;
+}
+
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
+/**
  * batadv_iv_hardif_neigh_print - print a single hop neighbour node
  * @seq: neighbour table seq_file struct
  * @hardif_neigh: hardif neighbour information
@@ -2027,37 +2239,43 @@ static void batadv_iv_neigh_print(struct batadv_priv *bat_priv,
 	if (batman_count == 0)
 		seq_puts(seq, "No batman nodes in range ...\n");
 }
+#endif
 
 /**
- * batadv_iv_ogm_neigh_cmp - compare the metrics of two neighbors
+ * batadv_iv_ogm_neigh_diff - calculate tq difference of two neighbors
  * @neigh1: the first neighbor object of the comparison
  * @if_outgoing1: outgoing interface for the first neighbor
  * @neigh2: the second neighbor object of the comparison
  * @if_outgoing2: outgoing interface for the second neighbor
+ * @diff: pointer to integer receiving the calculated difference
  *
- * Return: a value less, equal to or greater than 0 if the metric via neigh1 is
- * lower, the same as or higher than the metric via neigh2
+ * The content of *@diff is only valid when this function returns true.
+ * It is less, equal to or greater than 0 if the metric via neigh1 is lower,
+ * the same as or higher than the metric via neigh2
+ *
+ * Return: true when the difference could be calculated, false otherwise
  */
-static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
-				   struct batadv_hard_iface *if_outgoing1,
-				   struct batadv_neigh_node *neigh2,
-				   struct batadv_hard_iface *if_outgoing2)
+static bool batadv_iv_ogm_neigh_diff(struct batadv_neigh_node *neigh1,
+				     struct batadv_hard_iface *if_outgoing1,
+				     struct batadv_neigh_node *neigh2,
+				     struct batadv_hard_iface *if_outgoing2,
+				     int *diff)
 {
 	struct batadv_neigh_ifinfo *neigh1_ifinfo, *neigh2_ifinfo;
 	u8 tq1, tq2;
-	int diff;
+	bool ret = true;
 
 	neigh1_ifinfo = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
 	neigh2_ifinfo = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
 
 	if (!neigh1_ifinfo || !neigh2_ifinfo) {
-		diff = 0;
+		ret = false;
 		goto out;
 	}
 
 	tq1 = neigh1_ifinfo->bat_iv.tq_avg;
 	tq2 = neigh2_ifinfo->bat_iv.tq_avg;
-	diff = tq1 - tq2;
+	*diff = (int)tq1 - (int)tq2;
 
 out:
 	if (neigh1_ifinfo)
@@ -2065,6 +2283,162 @@ out:
 	if (neigh2_ifinfo)
 		batadv_neigh_ifinfo_put(neigh2_ifinfo);
 
+	return ret;
+}
+
+/**
+ * batadv_iv_ogm_neigh_dump_neigh - Dump a neighbour into a netlink message
+ * @msg: Netlink message to dump into
+ * @portid: Port making netlink request
+ * @seq: Sequence number of netlink message
+ * @hardif_neigh: Neighbour to be dumped
+ *
+ * Return: Error code, or 0 on success
+ */
+static int
+batadv_iv_ogm_neigh_dump_neigh(struct sk_buff *msg, u32 portid, u32 seq,
+			       struct batadv_hardif_neigh_node *hardif_neigh)
+{
+	void *hdr;
+	unsigned int last_seen_msecs;
+
+	last_seen_msecs = jiffies_to_msecs(jiffies - hardif_neigh->last_seen);
+
+	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_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))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+	return 0;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+/**
+ * batadv_iv_ogm_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 soft interface information
+ * @hard_iface: Hard interface to dump the neighbours for
+ * @idx_s: Number of entries to skip
+ *
+ * This function assumes the caller holds rcu_read_lock().
+ *
+ * Return: Error code, or 0 on success
+ */
+static int
+batadv_iv_ogm_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_iv_ogm_neigh_dump_neigh(msg, portid, seq,
+						   hardif_neigh)) {
+			*idx_s = idx - 1;
+			return -EMSGSIZE;
+		}
+	}
+
+	*idx_s = 0;
+	return 0;
+}
+
+/**
+ * batadv_iv_ogm_neigh_dump - Dump the neighbours into a message
+ * @msg: Netlink message to dump into
+ * @cb: Control block containing additional options
+ * @bat_priv: The bat priv with all the soft interface information
+ * @single_hardif: Limit dump to this hard interfaace
+ */
+static void
+batadv_iv_ogm_neigh_dump(struct sk_buff *msg, struct netlink_callback *cb,
+			 struct batadv_priv *bat_priv,
+			 struct batadv_hard_iface *single_hardif)
+{
+	struct batadv_hard_iface *hard_iface;
+	int i_hardif = 0;
+	int i_hardif_s = cb->args[0];
+	int idx = cb->args[1];
+	int portid = NETLINK_CB(cb->skb).portid;
+
+	rcu_read_lock();
+	if (single_hardif) {
+		if (i_hardif_s == 0) {
+			if (batadv_iv_ogm_neigh_dump_hardif(msg, portid,
+							    cb->nlh->nlmsg_seq,
+							    bat_priv,
+							    single_hardif,
+							    &idx) == 0)
+				i_hardif++;
+		}
+	} else {
+		list_for_each_entry_rcu(hard_iface, &batadv_hardif_list,
+					list) {
+			if (hard_iface->soft_iface != bat_priv->soft_iface)
+				continue;
+
+			if (i_hardif++ < i_hardif_s)
+				continue;
+
+			if (batadv_iv_ogm_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_iv_ogm_neigh_cmp - compare the metrics of two neighbors
+ * @neigh1: the first neighbor object of the comparison
+ * @if_outgoing1: outgoing interface for the first neighbor
+ * @neigh2: the second neighbor object of the comparison
+ * @if_outgoing2: outgoing interface for the second neighbor
+ *
+ * Return: a value less, equal to or greater than 0 if the metric via neigh1 is
+ * lower, the same as or higher than the metric via neigh2
+ */
+static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
+				   struct batadv_hard_iface *if_outgoing1,
+				   struct batadv_neigh_node *neigh2,
+				   struct batadv_hard_iface *if_outgoing2)
+{
+	bool ret;
+	int diff;
+
+	ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
+				       if_outgoing2, &diff);
+	if (!ret)
+		return 0;
+
 	return diff;
 }
 
@@ -2085,36 +2459,341 @@ batadv_iv_ogm_neigh_is_sob(struct batadv_neigh_node *neigh1,
 			   struct batadv_neigh_node *neigh2,
 			   struct batadv_hard_iface *if_outgoing2)
 {
-	struct batadv_neigh_ifinfo *neigh1_ifinfo, *neigh2_ifinfo;
-	u8 tq1, tq2;
 	bool ret;
+	int diff;
 
-	neigh1_ifinfo = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
-	neigh2_ifinfo = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
+	ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
+				       if_outgoing2, &diff);
+	if (!ret)
+		return false;
 
-	/* we can't say that the metric is better */
-	if (!neigh1_ifinfo || !neigh2_ifinfo) {
-		ret = false;
+	ret = diff > -BATADV_TQ_SIMILARITY_THRESHOLD;
+	return ret;
+}
+
+static void batadv_iv_iface_activate(struct batadv_hard_iface *hard_iface)
+{
+	/* begin scheduling originator messages on that interface */
+	batadv_iv_ogm_schedule(hard_iface);
+}
+
+static struct batadv_gw_node *
+batadv_iv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
+{
+	struct batadv_neigh_node *router;
+	struct batadv_neigh_ifinfo *router_ifinfo;
+	struct batadv_gw_node *gw_node, *curr_gw = NULL;
+	u64 max_gw_factor = 0;
+	u64 tmp_gw_factor = 0;
+	u8 max_tq = 0;
+	u8 tq_avg;
+	struct batadv_orig_node *orig_node;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {
+		orig_node = gw_node->orig_node;
+		router = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
+		if (!router)
+			continue;
+
+		router_ifinfo = batadv_neigh_ifinfo_get(router,
+							BATADV_IF_DEFAULT);
+		if (!router_ifinfo)
+			goto next;
+
+		if (!kref_get_unless_zero(&gw_node->refcount))
+			goto next;
+
+		tq_avg = router_ifinfo->bat_iv.tq_avg;
+
+		switch (atomic_read(&bat_priv->gw.sel_class)) {
+		case 1: /* fast connection */
+			tmp_gw_factor = tq_avg * tq_avg;
+			tmp_gw_factor *= gw_node->bandwidth_down;
+			tmp_gw_factor *= 100 * 100;
+			tmp_gw_factor >>= 18;
+
+			if ((tmp_gw_factor > max_gw_factor) ||
+			    ((tmp_gw_factor == max_gw_factor) &&
+			     (tq_avg > max_tq))) {
+				if (curr_gw)
+					batadv_gw_node_put(curr_gw);
+				curr_gw = gw_node;
+				kref_get(&curr_gw->refcount);
+			}
+			break;
+
+		default: /* 2:  stable connection (use best statistic)
+			  * 3:  fast-switch (use best statistic but change as
+			  *     soon as a better gateway appears)
+			  * XX: late-switch (use best statistic but change as
+			  *     soon as a better gateway appears which has
+			  *     $routing_class more tq points)
+			  */
+			if (tq_avg > max_tq) {
+				if (curr_gw)
+					batadv_gw_node_put(curr_gw);
+				curr_gw = gw_node;
+				kref_get(&curr_gw->refcount);
+			}
+			break;
+		}
+
+		if (tq_avg > max_tq)
+			max_tq = tq_avg;
+
+		if (tmp_gw_factor > max_gw_factor)
+			max_gw_factor = tmp_gw_factor;
+
+		batadv_gw_node_put(gw_node);
+
+next:
+		batadv_neigh_node_put(router);
+		if (router_ifinfo)
+			batadv_neigh_ifinfo_put(router_ifinfo);
+	}
+	rcu_read_unlock();
+
+	return curr_gw;
+}
+
+static bool batadv_iv_gw_is_eligible(struct batadv_priv *bat_priv,
+				     struct batadv_orig_node *curr_gw_orig,
+				     struct batadv_orig_node *orig_node)
+{
+	struct batadv_neigh_ifinfo *router_orig_ifinfo = NULL;
+	struct batadv_neigh_ifinfo *router_gw_ifinfo = NULL;
+	struct batadv_neigh_node *router_gw = NULL;
+	struct batadv_neigh_node *router_orig = NULL;
+	u8 gw_tq_avg, orig_tq_avg;
+	bool ret = false;
+
+	/* dynamic re-election is performed only on fast or late switch */
+	if (atomic_read(&bat_priv->gw.sel_class) <= 2)
+		return false;
+
+	router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
+	if (!router_gw) {
+		ret = true;
 		goto out;
 	}
 
-	tq1 = neigh1_ifinfo->bat_iv.tq_avg;
-	tq2 = neigh2_ifinfo->bat_iv.tq_avg;
-	ret = (tq1 - tq2) > -BATADV_TQ_SIMILARITY_THRESHOLD;
+	router_gw_ifinfo = batadv_neigh_ifinfo_get(router_gw,
+						   BATADV_IF_DEFAULT);
+	if (!router_gw_ifinfo) {
+		ret = true;
+		goto out;
+	}
+
+	router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
+	if (!router_orig)
+		goto out;
+
+	router_orig_ifinfo = batadv_neigh_ifinfo_get(router_orig,
+						     BATADV_IF_DEFAULT);
+	if (!router_orig_ifinfo)
+		goto out;
+
+	gw_tq_avg = router_gw_ifinfo->bat_iv.tq_avg;
+	orig_tq_avg = router_orig_ifinfo->bat_iv.tq_avg;
 
+	/* the TQ value has to be better */
+	if (orig_tq_avg < gw_tq_avg)
+		goto out;
+
+	/* if the routing class is greater than 3 the value tells us how much
+	 * greater the TQ value of the new gateway must be
+	 */
+	if ((atomic_read(&bat_priv->gw.sel_class) > 3) &&
+	    (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw.sel_class)))
+		goto out;
+
+	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+		   "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
+		   gw_tq_avg, orig_tq_avg);
+
+	ret = true;
 out:
-	if (neigh1_ifinfo)
-		batadv_neigh_ifinfo_put(neigh1_ifinfo);
-	if (neigh2_ifinfo)
-		batadv_neigh_ifinfo_put(neigh2_ifinfo);
+	if (router_gw_ifinfo)
+		batadv_neigh_ifinfo_put(router_gw_ifinfo);
+	if (router_orig_ifinfo)
+		batadv_neigh_ifinfo_put(router_orig_ifinfo);
+	if (router_gw)
+		batadv_neigh_node_put(router_gw);
+	if (router_orig)
+		batadv_neigh_node_put(router_orig);
 
 	return ret;
 }
 
-static void batadv_iv_iface_activate(struct batadv_hard_iface *hard_iface)
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
+/* fails if orig_node has no router */
+static int batadv_iv_gw_write_buffer_text(struct batadv_priv *bat_priv,
+					  struct seq_file *seq,
+					  const struct batadv_gw_node *gw_node)
 {
-	/* begin scheduling originator messages on that interface */
-	batadv_iv_ogm_schedule(hard_iface);
+	struct batadv_gw_node *curr_gw;
+	struct batadv_neigh_node *router;
+	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
+	int ret = -1;
+
+	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);
+
+	seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %u.%u/%u.%u MBit\n",
+		   (curr_gw == gw_node ? "=>" : "  "),
+		   gw_node->orig_node->orig,
+		   router_ifinfo->bat_iv.tq_avg, router->addr,
+		   router->if_incoming->net_dev->name,
+		   gw_node->bandwidth_down / 10,
+		   gw_node->bandwidth_down % 10,
+		   gw_node->bandwidth_up / 10,
+		   gw_node->bandwidth_up % 10);
+	ret = seq_has_overflowed(seq) ? -1 : 0;
+
+	if (curr_gw)
+		batadv_gw_node_put(curr_gw);
+out:
+	if (router_ifinfo)
+		batadv_neigh_ifinfo_put(router_ifinfo);
+	if (router)
+		batadv_neigh_node_put(router);
+	return ret;
+}
+
+static void batadv_iv_gw_print(struct batadv_priv *bat_priv,
+			       struct seq_file *seq)
+{
+	struct batadv_gw_node *gw_node;
+	int gw_count = 0;
+
+	seq_puts(seq,
+		 "      Gateway      (#/255)           Nexthop [outgoingIF]: advertised uplink bandwidth\n");
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {
+		/* fails if orig_node has no router */
+		if (batadv_iv_gw_write_buffer_text(bat_priv, seq, gw_node) < 0)
+			continue;
+
+		gw_count++;
+	}
+	rcu_read_unlock();
+
+	if (gw_count == 0)
+		seq_puts(seq, "No gateways in range ...\n");
+}
+#endif
+
+/**
+ * batadv_iv_gw_dump_entry - Dump a gateway 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 soft interface information
+ * @gw_node: Gateway to be dumped
+ *
+ * Return: Error code, or 0 on success
+ */
+static int batadv_iv_gw_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
+				   struct batadv_priv *bat_priv,
+				   struct batadv_gw_node *gw_node)
+{
+	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
+	struct batadv_neigh_node *router;
+	struct batadv_gw_node *curr_gw;
+	int ret = -EINVAL;
+	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, seq, &batadv_netlink_family,
+			  NLM_F_MULTI, BATADV_CMD_GET_GATEWAYS);
+	if (!hdr) {
+		ret = -ENOBUFS;
+		goto out;
+	}
+
+	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) ||
+	    nla_put_u8(msg, BATADV_ATTR_TQ, router_ifinfo->bat_iv.tq_avg) ||
+	    nla_put(msg, BATADV_ATTR_ROUTER, ETH_ALEN,
+		    router->addr) ||
+	    nla_put_string(msg, BATADV_ATTR_HARD_IFNAME,
+			   router->if_incoming->net_dev->name) ||
+	    nla_put_u32(msg, BATADV_ATTR_BANDWIDTH_DOWN,
+			gw_node->bandwidth_down) ||
+	    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:
+	if (router_ifinfo)
+		batadv_neigh_ifinfo_put(router_ifinfo);
+	if (router)
+		batadv_neigh_node_put(router);
+	return ret;
+}
+
+/**
+ * batadv_iv_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 soft interface information
+ */
+static void batadv_iv_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;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.gateway_list, list) {
+		if (idx++ < idx_skip)
+			continue;
+
+		if (batadv_iv_gw_dump_entry(msg, portid, cb->nlh->nlmsg_seq,
+					    bat_priv, gw_node)) {
+			idx_skip = idx - 1;
+			goto unlock;
+		}
+	}
+
+	idx_skip = idx;
+unlock:
+	rcu_read_unlock();
+
+	cb->args[0] = idx_skip;
 }
 
 static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
@@ -2129,14 +2808,28 @@ static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
 	.neigh = {
 		.cmp = batadv_iv_ogm_neigh_cmp,
 		.is_similar_or_better = batadv_iv_ogm_neigh_is_sob,
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
 		.print = batadv_iv_neigh_print,
+#endif
+		.dump = batadv_iv_ogm_neigh_dump,
 	},
 	.orig = {
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
 		.print = batadv_iv_ogm_orig_print,
+#endif
+		.dump = batadv_iv_ogm_orig_dump,
 		.free = batadv_iv_ogm_orig_free,
 		.add_if = batadv_iv_ogm_orig_add_if,
 		.del_if = batadv_iv_ogm_orig_del_if,
 	},
+	.gw = {
+		.get_best_gw_node = batadv_iv_gw_get_best_gw_node,
+		.is_eligible = batadv_iv_gw_is_eligible,
+#ifdef CONFIG_BATMAN_ADV_DEBUGFS
+		.print = batadv_iv_gw_print,
+#endif
+		.dump = batadv_iv_gw_dump,
+	},
 };
 
 int __init batadv_iv_init(void)