[Olsr-dev] [olsrd] [PATCH v3 1/1] gateway: fix lazy gateway selection

[Ferry Huberts]

From: Ferry Huberts <(spam-protected)>

Only an increase in the number of gateway nodes was seen as a network
in flux. A decrease in the number of gateway nodes was not taken into
account.

Signed-off-by: Ferry Huberts <(spam-protected)>
---
 src/gateway_default_handler.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/gateway_default_handler.c b/src/gateway_default_handler.c
index 9db8293..ef68935 100644
--- a/src/gateway_default_handler.c
+++ b/src/gateway_default_handler.c
@@ -90,21 +90,30 @@ static void gw_default_choose_gateway(void) {
   }
 }
 
-/* timer for lazy gateway selection */
+/**
+ * Timer callback for lazy gateway selection
+ *
+ * @param unused unused
+ */
 static void gw_default_timer(void *unused __attribute__ ((unused))) {
-  /* accept a 10% increase without trigger a stablecount reset */
-  if (tc_tree.count * 10 <= gw_def_nodecount * 11) {
+  /* accept a 10% increase/decrease in the number of gateway nodes without triggering a stablecount reset */
+  if (((tc_tree.count * 10) <= (gw_def_nodecount * 11)) ||
+      ((tc_tree.count * 10) >= (gw_def_nodecount *  9))) {
     gw_def_nodecount = tc_tree.count;
   }
-  if (tc_tree.count <= gw_def_nodecount) {
+
+  if (tc_tree.count == gw_def_nodecount) {
+    /* the number of gateway nodes is 'stable' */
     gw_def_stablecount++;
   }
   else {
+    /* there was a significant change in the number of gateway nodes */
     gw_def_nodecount = tc_tree.count;
     gw_def_stablecount = 0;
   }
 
   if (gw_def_stablecount >= olsr_cnf->smart_gw_stablecount) {
+    /* the number of gateway nodes is stable enough, so we should select a new gateway now */
     gw_default_choose_gateway();
   }
 }
-- 
1.7.10.4