From 66409193dc23ac6e7376cb1ef36c2ddd801b4e0a Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Thu, 1 Aug 2013 20:19:32 +0100
Subject: [PATCH] Sanity check for dhcp-range template.

---
 src/option.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/option.c b/src/option.c
index 006e4cc..c94bdd2 100644
--- a/src/option.c
+++ b/src/option.c
@@ -2460,6 +2460,15 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    
 	    if (!is_same_net6(&new->start6, &new->end6, new->prefix))
 	      ret_err(_("inconsistent DHCPv6 range"));
+	    
+	    if (new->flags & CONTEXT_TEMPLATE)
+	      {
+		struct in6_addr zero;
+		memset(&zero, 0, sizeof(zero));
+		if (!is_same_net6(&zero, &new->start6, new->prefix))
+		  ret_err(_("prefix must be zero with \"constructor:\" argument"));
+	      }
+	    
 	    if (addr6part(&new->start6) > addr6part(&new->end6))
 	      {
 		struct in6_addr tmp = new->start6;