The following commit has been merged in the master branch: commit 50164d8f500f1cd211178f7b3d062987d68fe013 Author: Antonio Quartulli a@unstable.cc Date: Sun Jul 3 12:46:34 2016 +0200

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: Antonio Quartulli a@unstable.cc Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Marek Lindner mareklindner@neomailbox.ch Signed-off-by: Simon Wunderlich sw@simonwunderlich.de

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c index 90fd5ee..1d777b1 100644 --- a/net/batman-adv/bat_v.c +++ b/net/batman-adv/bat_v.c @@ -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; }

/** diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index ec363f3..a77a179 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -360,9 +360,8 @@ 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_orig_node *orig_node) +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;

diff --git a/net/batman-adv/gateway_client.h b/net/batman-adv/gateway_client.h index 4c9edde..6b40432 100644 --- a/net/batman-adv/gateway_client.h +++ b/net/batman-adv/gateway_client.h @@ -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_ */