From ddc17434c4f1b48471171ca69de8acc0d6a4db2b Mon Sep 17 00:00:00 2001
From: Andrew Bettison <andrewb@zip.com.au>
Date: Mon, 30 Jul 2012 18:35:28 +0930
Subject: [PATCH] Fix next-hop logic for case of no interfaces up

---
 overlay_interface.c |  4 ++--
 overlay_route.c     | 27 ++++++++++++++-------------
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/overlay_interface.c b/overlay_interface.c
index cc2b4dd3..33eef34b 100644
--- a/overlay_interface.c
+++ b/overlay_interface.c
@@ -654,7 +654,7 @@ void overlay_interface_discover(struct sched_ent *alarm){
   int detect_real_interfaces = 0;
   
   /* Mark all UP interfaces as DETECTING, so we can tell which interfaces are new, and which are dead */
-  for(i = 0; i < overlay_interface_count; i++)
+  for (i = 0; i < overlay_interface_count; i++)
     if (overlay_interfaces[i].state==INTERFACE_STATE_UP)
       overlay_interfaces[i].state=INTERFACE_STATE_DETECTING;
 
@@ -665,7 +665,7 @@ void overlay_interface_discover(struct sched_ent *alarm){
       continue;
     }
     
-    for(i = 0; i < overlay_interface_count; i++)
+    for (i = 0; i < overlay_interface_count; i++)
       if (!strcasecmp(overlay_interfaces[i].name,r->namespec)){
 	if (overlay_interfaces[i].state==INTERFACE_STATE_DETECTING)
 	  overlay_interfaces[i].state=INTERFACE_STATE_UP;
diff --git a/overlay_route.c b/overlay_route.c
index 51fe28d4..a07fbc85 100644
--- a/overlay_route.c
+++ b/overlay_route.c
@@ -398,28 +398,29 @@ int overlay_get_nexthop(unsigned char *d,unsigned char *nexthop,int *interface)
   
   long long now = gettime_ms();
   overlay_neighbour *direct_neighbour=NULL;
-  
-  if (n->neighbour_id){
+
+  if (n->neighbour_id) {
     direct_neighbour = &overlay_neighbours[n->neighbour_id];
     overlay_route_recalc_neighbour_metrics(direct_neighbour, now);
     /* Is a direct neighbour.
        So in the absence of any better indirect route, we pick the interface that
-       we can hear this neighbour on the most reliably, and then send the frame 
+       we can hear this neighbour on the most reliably, and then send the frame
        via that interface and directly addressed to the recipient. */
-
-    *interface=0;
-    for(i=1;i<OVERLAY_MAX_INTERFACES;i++) {
-      if (overlay_interfaces[i].state==INTERFACE_STATE_UP &&
-	  direct_neighbour->scores[i]>direct_neighbour->scores[*interface]) *interface=i;
+    int ifn = -1;
+    for (i = 0; i < overlay_interface_count; ++i) {
+      if ( overlay_interfaces[i].state == INTERFACE_STATE_UP
+	&& (ifn == -1 || direct_neighbour->scores[i] > direct_neighbour->scores[ifn]))
+	ifn = i;
     }
-    if (direct_neighbour->scores[*interface]>0) {
-      bcopy(d,nexthop,SID_SIZE);
-      if (0) DEBUGF("nexthop is %s",alloca_tohex_sid(nexthop));
+    if (ifn != -1 && direct_neighbour->scores[ifn] > 0) {
+      *interface = ifn;
+      bcopy(d, nexthop, SID_SIZE);
+      if (debug&DEBUG_OVERLAYROUTING)
+	DEBUGF("nexthop is %s", alloca_tohex_sid(nexthop));
       return 0;
     }
-    // otherwise fall through
   }
-  
+
   /* Is not a direct neighbour.
      XXX - Very simplistic for now. */
   int o;