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Commit 50164d8f authored by Antonio Quartulli's avatar Antonio Quartulli Committed by Simon Wunderlich
Browse files

batman-adv: B.A.T.M.A.N. V - implement GW selection logic



Since the GW selection logic has been made routing protocol specific
it is now possible for B.A.T.M.A.N V to have its own mechanism by
providing the API implementation.

Implement the GW specific API in the B.A.T.M.A.N. V protocol in
order to provide a working GW selection mechanism.

Signed-off-by: default avatarAntonio Quartulli <a@unstable.cc>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
parent 34d99cfe
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+222 −1
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
@@ -40,6 +41,7 @@
#include "gateway_common.h"
#include "hard-interface.h"
#include "hash.h"
#include "log.h"
#include "originator.h"
#include "packet.h"

@@ -350,6 +352,213 @@ static ssize_t batadv_v_show_sel_class(struct batadv_priv *bat_priv, char *buff)
	return sprintf(buff, "%u.%u MBit\n", class / 10, class % 10);
}

/**
 * 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:
	if (router)
		batadv_neigh_node_put(router);
	if (router_ifinfo)
		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 soft 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 *gw_node, *curr_gw = NULL;
	u32 max_bw = 0, bw;

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.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;

		if (curr_gw)
			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 a originator would be selected as GW
 * @bat_priv: the bat priv with all the soft 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 *curr_gw = NULL, *orig_gw = NULL;
	u32 gw_throughput, orig_throughput, threshold;
	bool ret = false;

	threshold = atomic_read(&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_node)
		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:
	if (curr_gw)
		batadv_gw_node_put(curr_gw);
	if (orig_gw)
		batadv_gw_node_put(orig_gw);

	return ret;
}

/* fails if orig_node has no router */
static int batadv_v_gw_write_buffer_text(struct batadv_priv *bat_priv,
					 struct seq_file *seq,
					 const struct batadv_gw_node *gw_node)
{
	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 (%9u.%1u) %pM [%10s]: %u.%u/%u.%u MBit\n",
		   (curr_gw == gw_node ? "=>" : "  "),
		   gw_node->orig_node->orig,
		   router_ifinfo->bat_v.throughput / 10,
		   router_ifinfo->bat_v.throughput % 10, 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;
}

/**
 * batadv_v_gw_print - print the gateway list
 * @bat_priv: the bat priv with all the soft interface information
 * @seq: gateway table seq_file struct
 */
static void batadv_v_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        ( throughput)           Nexthop [outgoingIF]: advertised uplink bandwidth\n");

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
		/* fails if orig_node has no router */
		if (batadv_v_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");
}

static struct batadv_algo_ops batadv_batman_v __read_mostly = {
	.name = "BATMAN_V",
	.iface = {
@@ -371,6 +580,9 @@ static struct batadv_algo_ops batadv_batman_v __read_mostly = {
	.gw = {
		.store_sel_class = batadv_v_store_sel_class,
		.show_sel_class = batadv_v_show_sel_class,
		.get_best_gw_node = batadv_v_gw_get_best_gw_node,
		.is_eligible = batadv_v_gw_is_eligible,
		.print = batadv_v_gw_print,
	},
};

@@ -397,7 +609,16 @@ void batadv_v_hardif_init(struct batadv_hard_iface *hard_iface)
 */
int batadv_v_mesh_init(struct batadv_priv *bat_priv)
{
	return batadv_v_ogm_init(bat_priv);
	int ret = 0;

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

	/* set default throughput difference threshold to 5Mbps */
	atomic_set(&bat_priv->gw.sel_class, 50);

	return 0;
}

/**
+2 −3
Original line number Diff line number Diff line
@@ -360,8 +360,7 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv,
 *
 * Return: gateway node if found or NULL otherwise.
 */
static struct batadv_gw_node *
batadv_gw_node_get(struct batadv_priv *bat_priv,
struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig_node)
{
	struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
+2 −0
Original line number Diff line number Diff line
@@ -47,5 +47,7 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, struct sk_buff *skb);
enum batadv_dhcp_recipient
batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
			     u8 *chaddr);
struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig_node);

#endif /* _NET_BATMAN_ADV_GATEWAY_CLIENT_H_ */