[B.A.T.M.A.N.] [PATCH v5 0/6] GW code: make it algorithm-agnostic and add B.A.T.M.A.N. V support

[B.A.T.M.A.N.] [PATCH v5 0/6] GW code: make it algorithm-agnostic and add B.A.T.M.A.N. V support

[Antonio Quartulli]

This cover letter only tries to recap the changes applied from the previous
version. Please check the patch for major details.

Changes from v1:
- rebased on top of latest master (some patches from the previous patchset were
  merged already)
- accidental change to the GW table header moved to right patch
- remove bat_ prefix from API names
- API subobjects redefined as proper struct instead of anonymous ones to fix
  kernel-doc complaints
- bonus kernel-doc added
- missing include files added

Changes from v2:
- minimum default value of gw_sel_class restored to 1

Changes from v3:
- move "batman-adv: split routing API data structure in subobjects" as patch 1
- check if algo_ops->gw.get_best_gw_node was implemented before calling it
- add patch to disable GW mode knobs if API have not been implemented (6/6)

Changes from v4:
- drop CONFIG_BATMAN_ADV_BATMAN_V dependency when declaring batadv_gw_node_get()
  in gateway_client.h
- rebased on top of current master

Cheers,

Antonio Quartulli (4):
  batman-adv: make the GW selection class algorithm specific
  batman-adv: make GW election code protocol specific
  batman-adv: B.A.T.M.A.N. V - implement GW selection logic
  batman-adv: disable sysfs knobs when GW-mode is not implemented

 net/batman-adv/bat_iv_ogm.c     | 219 ++++++++++++++++++++++++++++++++++
 net/batman-adv/bat_v.c          | 254 +++++++++++++++++++++++++++++++++++++++-
 net/batman-adv/gateway_client.c | 222 +++++------------------------------
 net/batman-adv/gateway_client.h |   5 +
 net/batman-adv/gateway_common.c |   5 +-
 net/batman-adv/sysfs.c          |  62 +++++++++-
 net/batman-adv/types.h          |  23 ++++
 7 files changed, 592 insertions(+), 198 deletions(-)

-- 
2.8.4

[B.A.T.M.A.N.] [PATCH v5 1/4] batman-adv: make the GW selection class algorithm specific

[Antonio Quartulli]

The B.A.T.M.A.N. V algorithm uses a different metric compared to its
predecessor and for this reason the logic used to compute the best
Gateway is also changed. This means that the GW selection class
fed to this logic has a semantics that depends on the algorithm being
used.

Make the parsing and printing routine of the GW selection class
routing algorithm specific. Each algorithm can now parse (and print)
this value independently.

If no API is provided by any algorithm, the default is to use the
current mechanism of considering such value like an integer between
1 and 255.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
 net/batman-adv/bat_v.c | 34 ++++++++++++++++++++++++++++++++++
 net/batman-adv/sysfs.c | 34 ++++++++++++++++++++++++++++++++--
 net/batman-adv/types.h | 13 +++++++++++++
 3 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index 0366cbf..90fd5ee 100644
--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -21,8 +21,10 @@
 #include <linux/atomic.h>
 #include <linux/bug.h>
 #include <linux/cache.h>
+#include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
+#include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
@@ -34,6 +36,8 @@
 #include "bat_algo.h"
 #include "bat_v_elp.h"
 #include "bat_v_ogm.h"
+#include "gateway_client.h"
+#include "gateway_common.h"
 #include "hard-interface.h"
 #include "hash.h"
 #include "originator.h"
@@ -320,6 +324,32 @@ err_ifinfo1:
 	return ret;
 }
 
+static ssize_t batadv_v_store_sel_class(struct batadv_priv *bat_priv,
+					char *buff, size_t count)
+{
+	u32 old_class, class;
+
+	if (!batadv_parse_throughput(bat_priv->soft_iface, buff,
+				     "B.A.T.M.A.N. V GW selection class",
+				     &class))
+		return -EINVAL;
+
+	old_class = atomic_read(&bat_priv->gw.sel_class);
+	atomic_set(&bat_priv->gw.sel_class, class);
+
+	if (old_class != class)
+		batadv_gw_reselect(bat_priv);
+
+	return count;
+}
+
+static ssize_t batadv_v_show_sel_class(struct batadv_priv *bat_priv, char *buff)
+{
+	u32 class = atomic_read(&bat_priv->gw.sel_class);
+
+	return sprintf(buff, "%u.%u MBit\n", class / 10, class % 10);
+}
+
 static struct batadv_algo_ops batadv_batman_v __read_mostly = {
 	.name = "BATMAN_V",
 	.iface = {
@@ -338,6 +368,10 @@ static struct batadv_algo_ops batadv_batman_v __read_mostly = {
 	.orig = {
 		.print = batadv_v_orig_print,
 	},
+	.gw = {
+		.store_sel_class = batadv_v_store_sel_class,
+		.show_sel_class = batadv_v_show_sel_class,
+	},
 };
 
 /**
diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c
index fe9ca94..bb43742 100644
--- a/net/batman-adv/sysfs.c
+++ b/net/batman-adv/sysfs.c
@@ -514,6 +514,36 @@ static ssize_t batadv_store_gw_mode(struct kobject *kobj,
 	return count;
 }
 
+static ssize_t batadv_show_gw_sel_class(struct kobject *kobj,
+					struct attribute *attr, char *buff)
+{
+	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj);
+
+	if (bat_priv->algo_ops->gw.show_sel_class)
+		return bat_priv->algo_ops->gw.show_sel_class(bat_priv, buff);
+
+	return sprintf(buff, "%i\n", atomic_read(&bat_priv->gw.sel_class));
+}
+
+static ssize_t batadv_store_gw_sel_class(struct kobject *kobj,
+					 struct attribute *attr, char *buff,
+					 size_t count)
+{
+	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj);
+
+	if (buff[count - 1] == '\n')
+		buff[count - 1] = '\0';
+
+	if (bat_priv->algo_ops->gw.store_sel_class)
+		return bat_priv->algo_ops->gw.store_sel_class(bat_priv, buff,
+							      count);
+
+	return __batadv_store_uint_attr(buff, count, 1, BATADV_TQ_MAX_VALUE,
+					batadv_post_gw_reselect, attr,
+					&bat_priv->gw.sel_class,
+					bat_priv->soft_iface);
+}
+
 static ssize_t batadv_show_gw_bwidth(struct kobject *kobj,
 				     struct attribute *attr, char *buff)
 {
@@ -625,8 +655,8 @@ BATADV_ATTR_SIF_UINT(orig_interval, orig_interval, S_IRUGO | S_IWUSR,
 		     2 * BATADV_JITTER, INT_MAX, NULL);
 BATADV_ATTR_SIF_UINT(hop_penalty, hop_penalty, S_IRUGO | S_IWUSR, 0,
 		     BATADV_TQ_MAX_VALUE, NULL);
-BATADV_ATTR_SIF_UINT(gw_sel_class, gw.sel_class, S_IRUGO | S_IWUSR, 1,
-		     BATADV_TQ_MAX_VALUE, batadv_post_gw_reselect);
+static BATADV_ATTR(gw_sel_class, S_IRUGO | S_IWUSR, batadv_show_gw_sel_class,
+		   batadv_store_gw_sel_class);
 static BATADV_ATTR(gw_bandwidth, S_IRUGO | S_IWUSR, batadv_show_gw_bwidth,
 		   batadv_store_gw_bwidth);
 #ifdef CONFIG_BATMAN_ADV_MCAST
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 43db7b6..f24d93d 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1448,12 +1448,24 @@ struct batadv_algo_orig_ops {
 };
 
 /**
+ * struct batadv_algo_gw_ops - mesh algorithm callbacks (GW specific)
+ * @store_sel_class: parse and stores a new GW selection class
+ * @show_sel_class: prints the current GW selection class
+ */
+struct batadv_algo_gw_ops {
+	ssize_t (*store_sel_class)(struct batadv_priv *bat_priv, char *buff,
+				   size_t count);
+	ssize_t (*show_sel_class)(struct batadv_priv *bat_priv, char *buff);
+};
+
+/**
  * struct batadv_algo_ops - mesh algorithm callbacks
  * @list: list node for the batadv_algo_list
  * @name: name of the algorithm
  * @iface: callbacks related to interface handling
  * @neigh: callbacks related to neighbors handling
  * @orig: callbacks related to originators handling
+ * @gw: callbacks related to GW mode
  */
 struct batadv_algo_ops {
 	struct hlist_node list;
@@ -1461,6 +1473,7 @@ struct batadv_algo_ops {
 	struct batadv_algo_iface_ops iface;
 	struct batadv_algo_neigh_ops neigh;
 	struct batadv_algo_orig_ops orig;
+	struct batadv_algo_gw_ops gw;
 };
 
 /**
-- 
2.8.4

[B.A.T.M.A.N.] [PATCH v5 2/4] batman-adv: make GW election code protocol specific

[Antonio Quartulli]

Each routing protocol may have its own specific logic about
gateway election which is potentially based on the metric being
used.

Create two GW specific API functions and move the current election
logic in the B.A.T.M.A.N. IV specific code.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
 net/batman-adv/bat_iv_ogm.c     | 219 ++++++++++++++++++++++++++++++++++++++++
 net/batman-adv/gateway_client.c | 213 +++++---------------------------------
 net/batman-adv/gateway_client.h |   3 +
 net/batman-adv/gateway_common.c |   5 +-
 net/batman-adv/types.h          |  10 ++
 5 files changed, 258 insertions(+), 192 deletions(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index 19b0abd..e907492 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -51,6 +51,7 @@
 
 #include "bat_algo.h"
 #include "bitarray.h"
+#include "gateway_client.h"
 #include "hard-interface.h"
 #include "hash.h"
 #include "log.h"
@@ -2117,6 +2118,219 @@ static void batadv_iv_iface_activate(struct batadv_hard_iface *hard_iface)
 	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.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;
+	}
+
+	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 (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;
+}
+
+/* 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)
+{
+	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_printf(seq,
+		   "      Gateway      (#/255)           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_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");
+}
+
 static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
 	.name = "BATMAN_IV",
 	.iface = {
@@ -2137,6 +2351,11 @@ static struct batadv_algo_ops batadv_batman_iv __read_mostly = {
 		.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,
+		.print = batadv_iv_gw_print,
+	},
 };
 
 int __init batadv_iv_init(void)
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index 63a805d..564f9d9 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -80,12 +80,12 @@ static void batadv_gw_node_release(struct kref *ref)
  * batadv_gw_node_put - decrement the gw_node refcounter and possibly release it
  * @gw_node: gateway node to free
  */
-static void batadv_gw_node_put(struct batadv_gw_node *gw_node)
+void batadv_gw_node_put(struct batadv_gw_node *gw_node)
 {
 	kref_put(&gw_node->refcount, batadv_gw_node_release);
 }
 
-static struct batadv_gw_node *
+struct batadv_gw_node *
 batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
 {
 	struct batadv_gw_node *gw_node;
@@ -164,86 +164,6 @@ void batadv_gw_reselect(struct batadv_priv *bat_priv)
 	atomic_set(&bat_priv->gw.reselect, 1);
 }
 
-static struct batadv_gw_node *
-batadv_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.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;
-}
-
 /**
  * batadv_gw_check_client_stop - check if client mode has been switched off
  * @bat_priv: the bat priv with all the soft interface information
@@ -287,12 +207,15 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
 	if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
 		goto out;
 
+	if (!bat_priv->algo_ops->gw.get_best_gw_node)
+		goto out;
+
 	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
 
 	if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 		goto out;
 
-	next_gw = batadv_gw_get_best_gw_node(bat_priv);
+	next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
 
 	if (curr_gw == next_gw)
 		goto out;
@@ -360,70 +283,31 @@ out:
 void batadv_gw_check_election(struct batadv_priv *bat_priv,
 			      struct batadv_orig_node *orig_node)
 {
-	struct batadv_neigh_ifinfo *router_orig_tq = NULL;
-	struct batadv_neigh_ifinfo *router_gw_tq = NULL;
 	struct batadv_orig_node *curr_gw_orig;
-	struct batadv_neigh_node *router_gw = NULL;
-	struct batadv_neigh_node *router_orig = NULL;
-	u8 gw_tq_avg, orig_tq_avg;
+
+	/* abort immediately if the routing algorithm does not support gateway
+	 * election
+	 */
+	if (!bat_priv->algo_ops->gw.is_eligible)
+		return;
 
 	curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
 	if (!curr_gw_orig)
 		goto reselect;
 
-	router_gw = batadv_orig_router_get(curr_gw_orig, BATADV_IF_DEFAULT);
-	if (!router_gw)
-		goto reselect;
-
-	router_gw_tq = batadv_neigh_ifinfo_get(router_gw,
-					       BATADV_IF_DEFAULT);
-	if (!router_gw_tq)
-		goto reselect;
-
 	/* this node already is the gateway */
 	if (curr_gw_orig == orig_node)
 		goto out;
 
-	router_orig = batadv_orig_router_get(orig_node, BATADV_IF_DEFAULT);
-	if (!router_orig)
-		goto out;
-
-	router_orig_tq = batadv_neigh_ifinfo_get(router_orig,
-						 BATADV_IF_DEFAULT);
-	if (!router_orig_tq)
-		goto out;
-
-	gw_tq_avg = router_gw_tq->bat_iv.tq_avg;
-	orig_tq_avg = router_orig_tq->bat_iv.tq_avg;
-
-	/* the TQ value has to be better */
-	if (orig_tq_avg < gw_tq_avg)
+	if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig,
+						orig_node))
 		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);
-
 reselect:
 	batadv_gw_reselect(bat_priv);
 out:
 	if (curr_gw_orig)
 		batadv_orig_node_put(curr_gw_orig);
-	if (router_gw)
-		batadv_neigh_node_put(router_gw);
-	if (router_orig)
-		batadv_neigh_node_put(router_orig);
-	if (router_gw_tq)
-		batadv_neigh_ifinfo_put(router_gw_tq);
-	if (router_orig_tq)
-		batadv_neigh_ifinfo_put(router_orig_tq);
 }
 
 /**
@@ -585,80 +469,31 @@ void batadv_gw_node_free(struct batadv_priv *bat_priv)
 	spin_unlock_bh(&bat_priv->gw.list_lock);
 }
 
-/* fails if orig_node has no router */
-static int batadv_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 (%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;
-}
-
 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
 {
 	struct net_device *net_dev = (struct net_device *)seq->private;
 	struct batadv_priv *bat_priv = netdev_priv(net_dev);
 	struct batadv_hard_iface *primary_if;
-	struct batadv_gw_node *gw_node;
-	int gw_count = 0;
 
 	primary_if = batadv_seq_print_text_primary_if_get(seq);
 	if (!primary_if)
-		goto out;
+		return 0;
 
-	seq_printf(seq,
-		   "      Gateway      (#/255)           Nexthop [outgoingIF]: advertised uplink bandwidth ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
+	seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s %s)]\n",
 		   BATADV_SOURCE_VERSION, primary_if->net_dev->name,
-		   primary_if->net_dev->dev_addr, net_dev->name);
+		   primary_if->net_dev->dev_addr, net_dev->name,
+		   bat_priv->algo_ops->name);
 
-	rcu_read_lock();
-	hlist_for_each_entry_rcu(gw_node, &bat_priv->gw.list, list) {
-		/* fails if orig_node has no router */
-		if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
-			continue;
+	batadv_hardif_put(primary_if);
 
-		gw_count++;
+	if (!bat_priv->algo_ops->gw.print) {
+		seq_puts(seq,
+			 "No printing function for this routing protocol\n");
+		return 0;
 	}
-	rcu_read_unlock();
 
-	if (gw_count == 0)
-		seq_puts(seq, "No gateways in range ...\n");
+	bat_priv->algo_ops->gw.print(bat_priv, seq);
 
-out:
-	if (primary_if)
-		batadv_hardif_put(primary_if);
 	return 0;
 }
 
diff --git a/net/batman-adv/gateway_client.h b/net/batman-adv/gateway_client.h
index 582dd8c..4c9edde 100644
--- a/net/batman-adv/gateway_client.h
+++ b/net/batman-adv/gateway_client.h
@@ -39,6 +39,9 @@ void batadv_gw_node_update(struct batadv_priv *bat_priv,
 void batadv_gw_node_delete(struct batadv_priv *bat_priv,
 			   struct batadv_orig_node *orig_node);
 void batadv_gw_node_free(struct batadv_priv *bat_priv);
+void batadv_gw_node_put(struct batadv_gw_node *gw_node);
+struct batadv_gw_node *
+batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv);
 int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset);
 bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, struct sk_buff *skb);
 enum batadv_dhcp_recipient
diff --git a/net/batman-adv/gateway_common.c b/net/batman-adv/gateway_common.c
index d7bc6a8..2118481 100644
--- a/net/batman-adv/gateway_common.c
+++ b/net/batman-adv/gateway_common.c
@@ -241,10 +241,9 @@ static void batadv_gw_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
 
 	batadv_gw_node_update(bat_priv, orig, &gateway);
 
-	/* restart gateway selection if fast or late switching was enabled */
+	/* restart gateway selection */
 	if ((gateway.bandwidth_down != 0) &&
-	    (atomic_read(&bat_priv->gw.mode) == BATADV_GW_MODE_CLIENT) &&
-	    (atomic_read(&bat_priv->gw.sel_class) > 2))
+	    (atomic_read(&bat_priv->gw.mode) == BATADV_GW_MODE_CLIENT))
 		batadv_gw_check_election(bat_priv, orig);
 }
 
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index f24d93d..426f710 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1451,11 +1451,21 @@ struct batadv_algo_orig_ops {
  * struct batadv_algo_gw_ops - mesh algorithm callbacks (GW specific)
  * @store_sel_class: parse and stores a new GW selection class
  * @show_sel_class: prints the current GW selection class
+ * @get_best_gw_node: select the best GW from the list of available nodes
+ * @is_eligible: check if a newly discovered GW is a potential candidate for
+ *  the election as best GW
+ * @print: print the gateway table (optional)
  */
 struct batadv_algo_gw_ops {
 	ssize_t (*store_sel_class)(struct batadv_priv *bat_priv, char *buff,
 				   size_t count);
 	ssize_t (*show_sel_class)(struct batadv_priv *bat_priv, char *buff);
+	struct batadv_gw_node *(*get_best_gw_node)
+		(struct batadv_priv *bat_priv);
+	bool (*is_eligible)(struct batadv_priv *bat_priv,
+			    struct batadv_orig_node *curr_gw_orig,
+			    struct batadv_orig_node *orig_node);
+	void (*print)(struct batadv_priv *bat_priv, struct seq_file *seq);
 };
 
 /**
-- 
2.8.4

[B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Antonio Quartulli]

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>
---
 net/batman-adv/bat_v.c          | 220 +++++++++++++++++++++++++++++++++++++++-
 net/batman-adv/gateway_client.c |   9 +-
 net/batman-adv/gateway_client.h |   2 +
 3 files changed, 227 insertions(+), 4 deletions(-)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index 90fd5ee..f68be92 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 +352,210 @@ 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 + 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_printf(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 +577,9 @@ 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 +606,16 @@ 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 564f9d9..a77a179 100644
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -215,6 +215,10 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
 	if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
 		goto out;
 
+	/* if gw.reselect is set to 1 it means that a previous call to
+	 * gw.is_eligible() said that we have a new best GW, therefore it can
+	 * now be picked from the list and selected
+	 */
 	next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
 
 	if (curr_gw == next_gw)
@@ -356,9 +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_ */
-- 
2.8.4

[B.A.T.M.A.N.] [PATCH v5 4/4] batman-adv: disable sysfs knobs when GW-mode is not implemented

[Antonio Quartulli]

Now that the GW-mode code is algorithm specific, batman-adv expects the
routing algorithm to implement some APIs to make it work.

However, such APIs are not mandatory, therefore we might have algorithms
not providing them. In this case all the sysfs knobs related to GW-mode
should be deactivated to make sure that settings injected by the user
for this feature are rejected.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
 net/batman-adv/sysfs.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c
index bb43742..486fdd6 100644
--- a/net/batman-adv/sysfs.c
+++ b/net/batman-adv/sysfs.c
@@ -428,6 +428,13 @@ static ssize_t batadv_show_gw_mode(struct kobject *kobj, struct attribute *attr,
 	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj);
 	int bytes_written;
 
+	/* GW mode is not available if the routing algorithm in use does not
+	 * implement the GW API
+	 */
+	if (!bat_priv->algo_ops->gw.get_best_gw_node ||
+	    !bat_priv->algo_ops->gw.is_eligible)
+		return -ENOENT;
+
 	switch (atomic_read(&bat_priv->gw.mode)) {
 	case BATADV_GW_MODE_CLIENT:
 		bytes_written = sprintf(buff, "%s\n",
@@ -455,6 +462,13 @@ static ssize_t batadv_store_gw_mode(struct kobject *kobj,
 	char *curr_gw_mode_str;
 	int gw_mode_tmp = -1;
 
+	/* toggling GW mode is allowed only if the routing algorithm in use
+	 * provides the GW API
+	 */
+	if (!bat_priv->algo_ops->gw.get_best_gw_node ||
+	    !bat_priv->algo_ops->gw.is_eligible)
+		return -EINVAL;
+
 	if (buff[count - 1] == '\n')
 		buff[count - 1] = '\0';
 
@@ -519,6 +533,13 @@ static ssize_t batadv_show_gw_sel_class(struct kobject *kobj,
 {
 	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj);
 
+	/* GW selection class is not available if the routing algorithm in use
+	 * does not implement the GW API
+	 */
+	if (!bat_priv->algo_ops->gw.get_best_gw_node ||
+	    !bat_priv->algo_ops->gw.is_eligible)
+		return -ENOENT;
+
 	if (bat_priv->algo_ops->gw.show_sel_class)
 		return bat_priv->algo_ops->gw.show_sel_class(bat_priv, buff);
 
@@ -531,6 +552,13 @@ static ssize_t batadv_store_gw_sel_class(struct kobject *kobj,
 {
 	struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj);
 
+	/* setting the GW selection class is allowed only if the routing
+	 * algorithm in use implements the GW API
+	 */
+	if (!bat_priv->algo_ops->gw.get_best_gw_node ||
+	    !bat_priv->algo_ops->gw.is_eligible)
+		return -EINVAL;
+
 	if (buff[count - 1] == '\n')
 		buff[count - 1] = '\0';
 
-- 
2.8.4

Re: [B.A.T.M.A.N.] [PATCH v5 1/4] batman-adv: make the GW selection class algorithm specific

[Sven Eckelmann]

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On Sunday 12 June 2016 12:14:23 Antonio Quartulli wrote:
[...]
> +	if (bat_priv->algo_ops->gw.show_sel_class)
> +		return bat_priv->algo_ops->gw.show_sel_class(bat_priv, buff);
[...]
> +	if (bat_priv->algo_ops->gw.store_sel_class)
> +		return bat_priv->algo_ops->gw.store_sel_class(bat_priv, buff,
> +							      count);
[...]
>  /**
> + * struct batadv_algo_gw_ops - mesh algorithm callbacks (GW specific)
> + * @store_sel_class: parse and stores a new GW selection class
> + * @show_sel_class: prints the current GW selection class
> + */
> +struct batadv_algo_gw_ops {
> +	ssize_t (*store_sel_class)(struct batadv_priv *bat_priv, char *buff,
> +				   size_t count);
> +	ssize_t (*show_sel_class)(struct batadv_priv *bat_priv, char *buff);
> +};

Looks like these two are also optional. Can someone please add the "(optional)"
string to the kernel-doc like it was done in the initial batadv_algo_ops
patches? Thanks

Same for get_best_gw_node, is_eligible and print in patch 2

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 4/4] batman-adv: disable sysfs knobs when GW-mode is not implemented

[Sven Eckelmann]

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On Sunday 12 June 2016 12:14:26 Antonio Quartulli wrote:
> Now that the GW-mode code is algorithm specific, batman-adv expects the
> routing algorithm to implement some APIs to make it work.
> 
> However, such APIs are not mandatory, therefore we might have algorithms
> not providing them. In this case all the sysfs knobs related to GW-mode
> should be deactivated to make sure that settings injected by the user
> for this feature are rejected.
> 
> Signed-off-by: Antonio Quartulli <a@unstable.cc>
> ---

Reviewed-by: Sven Eckelmann <sven@narfation.org>

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Sven Eckelmann]

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On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> --- a/net/batman-adv/gateway_client.c
> +++ b/net/batman-adv/gateway_client.c
> @@ -215,6 +215,10 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
>         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
>                 goto out;
>  
> +       /* if gw.reselect is set to 1 it means that a previous call to
> +        * gw.is_eligible() said that we have a new best GW, therefore it can
> +        * now be picked from the list and selected
> +        */
>         next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);

I would guess that this should be either in patch 2/4 on in an extra patch. At
least it is about nothing which is touched otherwise in this patch

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Sven Eckelmann]

[-- Attachment #1: Type: text/plain, Size: 612 bytes --]

On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> +       if (orig_throughput < (gw_throughput + threshold))
> +               goto out;

Possible overflow problem in batadv_v_gw_is_eligible. We don't
know what the user will add here and what the gw_throughput is.

We already had a similar problem in the BATMAN_IV gw selection
code which resulted in weird gw selections. See f63c54bba31d
("batman-adv: Avoid u32 overflow during gateway select").


    if (orig_throughput < gw_throughput)
        goto out;

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

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Sven Eckelmann]

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On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> +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_printf(seq,
> +                  "      Gateway        ( throughput)           Nexthop [outgoingIF]: advertised uplink bandwidth\n");

Maybe you wanted to use seq_puts here. At least you've used it in
similar changes.

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 2/4] batman-adv: make GW election code protocol specific

[Sven Eckelmann]

[-- Attachment #1: Type: text/plain, Size: 499 bytes --]

On Sunday 12 June 2016 12:14:24 Antonio Quartulli wrote:
> +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_printf(seq,
> +                  "      Gateway      (#/255)           Nexthop [outgoingIF]: advertised uplink bandwidth\n");

Maybe you wanted to use seq_puts here. At least you've used it in
similar changes.

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 1/4] batman-adv: make the GW selection class algorithm specific

[Antonio Quartulli]

[-- Attachment #1: Type: text/plain, Size: 1171 bytes --]

On Mon, Jun 13, 2016 at 12:45:17PM +0200, Sven Eckelmann wrote:
> On Sunday 12 June 2016 12:14:23 Antonio Quartulli wrote:
> [...]
> > +	if (bat_priv->algo_ops->gw.show_sel_class)
> > +		return bat_priv->algo_ops->gw.show_sel_class(bat_priv, buff);
> [...]
> > +	if (bat_priv->algo_ops->gw.store_sel_class)
> > +		return bat_priv->algo_ops->gw.store_sel_class(bat_priv, buff,
> > +							      count);
> [...]
> >  /**
> > + * struct batadv_algo_gw_ops - mesh algorithm callbacks (GW specific)
> > + * @store_sel_class: parse and stores a new GW selection class
> > + * @show_sel_class: prints the current GW selection class
> > + */
> > +struct batadv_algo_gw_ops {
> > +	ssize_t (*store_sel_class)(struct batadv_priv *bat_priv, char *buff,
> > +				   size_t count);
> > +	ssize_t (*show_sel_class)(struct batadv_priv *bat_priv, char *buff);
> > +};
> 
> Looks like these two are also optional. Can someone please add the "(optional)"
> string to the kernel-doc like it was done in the initial batadv_algo_ops
> patches? Thanks
> 
> Same for get_best_gw_node, is_eligible and print in patch 2

Sure!

Thanks!



-- 
Antonio Quartulli

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Antonio Quartulli]

[-- Attachment #1: Type: text/plain, Size: 939 bytes --]

On Mon, Jun 13, 2016 at 01:12:52PM +0200, Sven Eckelmann wrote:
> On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> > --- a/net/batman-adv/gateway_client.c
> > +++ b/net/batman-adv/gateway_client.c
> > @@ -215,6 +215,10 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
> >         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
> >                 goto out;
> >  
> > +       /* if gw.reselect is set to 1 it means that a previous call to
> > +        * gw.is_eligible() said that we have a new best GW, therefore it can
> > +        * now be picked from the list and selected
> > +        */
> >         next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
> 
> I would guess that this should be either in patch 2/4 on in an extra patch. At
> least it is about nothing which is touched otherwise in this patch

mh...you are right.

will fix this

-- 
Antonio Quartulli

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Antonio Quartulli]

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On Mon, Jun 13, 2016 at 01:26:31PM +0200, Sven Eckelmann wrote:
> On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> > +       if (orig_throughput < (gw_throughput + threshold))
> > +               goto out;
> 
> Possible overflow problem in batadv_v_gw_is_eligible. We don't
> know what the user will add here and what the gw_throughput is.
> 
> We already had a similar problem in the BATMAN_IV gw selection
> code which resulted in weird gw selections. See f63c54bba31d
> ("batman-adv: Avoid u32 overflow during gateway select").

Sven, correct me if I am wrong, but in f63c54bba31d we are changing the type of
the variables aimed to contain the value computed by the "overflowing"
operation, while in this case we have everything in a if condition: should the
temporary result be implicitly casted to a larger variable as required ?

I may be wrong - but I wanted to ask you to be sure.

Cheers,


-- 
Antonio Quartulli

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Antonio Quartulli]

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On Mon, Jun 13, 2016 at 01:12:52PM +0200, Sven Eckelmann wrote:
> On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> > --- a/net/batman-adv/gateway_client.c
> > +++ b/net/batman-adv/gateway_client.c
> > @@ -215,6 +215,10 @@ void batadv_gw_election(struct batadv_priv *bat_priv)
> >         if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
> >                 goto out;
> >  
> > +       /* if gw.reselect is set to 1 it means that a previous call to
> > +        * gw.is_eligible() said that we have a new best GW, therefore it can
> > +        * now be picked from the list and selected
> > +        */
> >         next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
> 
> I would guess that this should be either in patch 2/4 on in an extra patch. At
> least it is about nothing which is touched otherwise in this patch

Good catch :) Thanks !

I am moving the comment to patch 2/4.

Cheers,

-- 
Antonio Quartulli

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Sven Eckelmann]

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On Monday 27 June 2016 10:36:13 Antonio Quartulli wrote:
> On Mon, Jun 13, 2016 at 01:26:31PM +0200, Sven Eckelmann wrote:
> > On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> > > +       if (orig_throughput < (gw_throughput + threshold))
> > > +               goto out;
> > 
> > Possible overflow problem in batadv_v_gw_is_eligible. We don't
> > know what the user will add here and what the gw_throughput is.
> > 
> > We already had a similar problem in the BATMAN_IV gw selection
> > code which resulted in weird gw selections. See f63c54bba31d
> > ("batman-adv: Avoid u32 overflow during gateway select").
> 
> Sven, correct me if I am wrong, but in f63c54bba31d we are changing the type of
> the variables aimed to contain the value computed by the "overflowing"
> operation, while in this case we have everything in a if condition: should the
> temporary result be implicitly casted to a larger variable as required ?

No, it isn't casted to a larger type. Yes, C has some wild casting rules but I
would not be aware of an "help the programmer to avoid overflows" casting
rule.

We had no other idea how to fix it in the mentioned commit. But here we can do
it without casting to u64.

Kind regards,
	Sven

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Re: [B.A.T.M.A.N.] [PATCH v5 3/4] batman-adv: B.A.T.M.A.N. V - implement GW selection logic

[Antonio Quartulli]

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On Mon, Jun 27, 2016 at 08:19:22AM +0200, Sven Eckelmann wrote:
> On Monday 27 June 2016 10:36:13 Antonio Quartulli wrote:
> > On Mon, Jun 13, 2016 at 01:26:31PM +0200, Sven Eckelmann wrote:
> > > On Sunday 12 June 2016 12:14:25 Antonio Quartulli wrote:
> > > > +       if (orig_throughput < (gw_throughput + threshold))
> > > > +               goto out;
> > > 
> > > Possible overflow problem in batadv_v_gw_is_eligible. We don't
> > > know what the user will add here and what the gw_throughput is.
> > > 
> > > We already had a similar problem in the BATMAN_IV gw selection
> > > code which resulted in weird gw selections. See f63c54bba31d
> > > ("batman-adv: Avoid u32 overflow during gateway select").
> > 
> > Sven, correct me if I am wrong, but in f63c54bba31d we are changing the type of
> > the variables aimed to contain the value computed by the "overflowing"
> > operation, while in this case we have everything in a if condition: should the
> > temporary result be implicitly casted to a larger variable as required ?
> 
> No, it isn't casted to a larger type. Yes, C has some wild casting rules but I
> would not be aware of an "help the programmer to avoid overflows" casting
> rule.
> 
> We had no other idea how to fix it in the mentioned commit. But here we can do
> it without casting to u64.

ok, thanks !

I will modify the patch in the next series.

Cheers,


-- 
Antonio Quartulli

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