From 0e070cd2fd4bbff31c3886e70aaed2319911cc37 Mon Sep 17 00:00:00 2001
From: Jarrod Johnson <jjohnson2@lenovo.com>
Date: Mon, 5 Mar 2018 13:47:49 -0500
Subject: [PATCH] Fix infinite loop if unfortunate IPv6 encountered

---
 xCAT-server/lib/xcat/plugins/dhcp.pm | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xCAT-server/lib/xcat/plugins/dhcp.pm b/xCAT-server/lib/xcat/plugins/dhcp.pm
index 503d1e7fe..1d3c2bfd2 100644
--- a/xCAT-server/lib/xcat/plugins/dhcp.pm
+++ b/xCAT-server/lib/xcat/plugins/dhcp.pm
@@ -2187,7 +2187,10 @@ sub getzonesfornet {
             $rev .= $_ . ".";
             $nibbs--;
         }
-        while ($nibbs) {
+	if ($nibbs < 1) {
+		return ();  # Don't presume to handle maskless subnets...
+        }
+        while ($nibbs > 0) {
             $rev .= "0.";
             $nibbs--;
         }