From 2f6f9dc381fee47735b8fdf2bcad02ca12540f6e Mon Sep 17 00:00:00 2001
From: Chris Buechler <cmb@pfsense.org>
Date: Mon, 8 Dec 2008 02:31:36 +0000
Subject: [PATCH] fix CARP panics with VLANs

---
 etc/inc/interfaces.inc | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/etc/inc/interfaces.inc b/etc/inc/interfaces.inc
index 1621a29d9c..c305910ec9 100644
--- a/etc/inc/interfaces.inc
+++ b/etc/inc/interfaces.inc
@@ -68,7 +68,18 @@ function interface_vlan_configure($if, $tag, $vlanif = "") {
 	mwexec("/sbin/ifconfig " . escapeshellarg($if) . " up vlanhwtag vlanmtu");
 
 	if ($g['booting'] || !(empty($vlanif))) {
-		mwexec("/sbin/ifconfig {$vlanif} destroy", true);
+		/* before destroying, see if CARP is in use
+		  If an interface containing an active CARP IP is destroyed,
+		  the CARP interface will hang in INIT and must be destroyed
+		  itself before it will function again (which causes a panic).
+		  Trying to configure a CARP interface stuck in INIT will
+		  cause a panic as well.  -cmb
+		*/
+		$carpcount = find_number_of_needed_carp_interfaces();
+		/* will continue to destroy VLANs where CARP is not in use
+		  to retain previous behavior and avoid regressions */
+		if($carpcount < 1)
+			mwexec("/sbin/ifconfig {$vlanif} destroy");
 		mwexec("/sbin/ifconfig {$vlanif} create");
 	} else 
 		$vlanif = exec("/sbin/ifconfig vlan create");