From 5b56f96aaad4a55a26576e0610fb49bde448dabe Mon Sep 17 00:00:00 2001
From: Gurucharan Shetty <gshetty@nicira.com>
Date: Wed, 13 Mar 2013 12:24:54 -0700
Subject: [PATCH] rhel: Prevent duplicate ifup calls.

When we configure OVS using rhel ifupdown scripts,
we call ifup on a bridge twice. Once while configuring the
bridge and once while configuring the ports of the bridge.
This looks harmless but unnecessary. This patch fixes the
behavior.

Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
---
 rhel/README.RHEL                            |  6 +++-
 rhel/etc_sysconfig_network-scripts_ifup-ovs | 38 +++++++++++++++++----
 2 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/rhel/README.RHEL b/rhel/README.RHEL
index d9b68e4b3..ba2774a66 100644
--- a/rhel/README.RHEL
+++ b/rhel/README.RHEL
@@ -42,11 +42,15 @@ assignments.  The following OVS-specific variable names are supported:
 Note
 ----
 
-"ifdown" on a bridge will not bring individual ports on the bridge
+* "ifdown" on a bridge will not bring individual ports on the bridge
 down.  "ifup" on a bridge will not add ports to the bridge.  This
 behavior should be compatible with standard bridges (with
 TYPE=Bridge).
 
+* If 'ifup' on an interface is called multiple times, one can see
+"RTNETLINK answers: File exists" printed on the console. This comes from
+ifup-eth trying to add zeroconf route multiple times and is harmless.
+
 Examples
 --------
 
diff --git a/rhel/etc_sysconfig_network-scripts_ifup-ovs b/rhel/etc_sysconfig_network-scripts_ifup-ovs
index ae095a083..b36252020 100755
--- a/rhel/etc_sysconfig_network-scripts_ifup-ovs
+++ b/rhel/etc_sysconfig_network-scripts_ifup-ovs
@@ -34,7 +34,7 @@ if [ ! -x ${OTHERSCRIPT} ]; then
 	OTHERSCRIPT="/etc/sysconfig/network-scripts/ifup-eth"
 fi
 
-check_recursion()
+check_recursion ()
 {
 	[ -n "${UPPEDSTACK}" ] && for _r in ${UPPEDSTACK}; do
 		[ "$_r" = "$1" ] && return 1
@@ -43,6 +43,13 @@ check_recursion()
 	return 0
 }
 
+ifup_ovs_bridge ()
+{
+	if ovs-vsctl br-exists "${OVS_BRIDGE}"; then :; else
+		/sbin/ifup "${OVS_BRIDGE}"
+	fi
+}
+
 if [ -z "${UPPEDSTACK}" ]; then
 	UPPEDSTACK="${DEVICE}"
 fi
@@ -57,7 +64,22 @@ done
 
 case "$TYPE" in
 	OVSBridge)
-		ovs-vsctl -t ${TIMEOUT} -- --may-exist add-br "$DEVICE" $OVS_OPTIONS ${OVS_EXTRA+-- $OVS_EXTRA}
+		# If bridge already exists and is up, it has been configured through
+		# other cases like OVSPort, OVSIntPort and OVSBond. If it is down or
+		# it does not exist, create it. It is possible for a bridge to exist
+		# because it remained in the OVSDB for some reason, but it won't be up.
+		if check_device_down "${DEVICE}"; then
+			ovs-vsctl -t ${TIMEOUT} -- --may-exist add-br "$DEVICE" $OVS_OPTIONS \
+			${OVS_EXTRA+-- $OVS_EXTRA}
+		else
+			OVSBRIDGECONFIGURED="yes"
+		fi
+
+		# When dhcp is enabled, the assumption is that there will be a port to
+		# attach (otherwise, we can't reach out for dhcp). So, we do not
+		# configure the bridge through rhel's ifup infrastructure unless
+		# it is being configured after the port has been configured.
+		# The "OVSINTF" is set only after the port is configured.
 		if [ "${OVSBOOTPROTO}" = "dhcp" ] && [ -n "${OVSINTF}" ]; then
 			case " ${OVSDHCPINTERFACES} " in
 				*" ${OVSINTF} "*)
@@ -65,25 +87,29 @@ case "$TYPE" in
 				;;
 			esac
 		fi
-		if [ "${OVSBOOTPROTO}" != "dhcp" ] && [ -z "${OVSINTF}" ]; then
+
+		# When dhcp is not enabled, it is possible that someone may want
+		# a standalone bridge (i.e it may not have any ports). Configure it.
+		if [ "${OVSBOOTPROTO}" != "dhcp" ] && [ -z "${OVSINTF}" ] && \
+			[ "${OVSBRIDGECONFIGURED}" != "yes" ]; then
 			${OTHERSCRIPT} ${CONFIG}
 		fi
 		[ -n "${STP}" ] && ovs-vsctl --no-wait set bridge "${DEVICE}" stp_enable="${STP}"
 		exit 0
 		;;
 	OVSPort)
-		/sbin/ifup "$OVS_BRIDGE"
+		ifup_ovs_bridge
 		${OTHERSCRIPT} ${CONFIG} ${2}
 		ovs-vsctl -t ${TIMEOUT} -- --may-exist add-port "$OVS_BRIDGE" "$DEVICE" $OVS_OPTIONS ${OVS_EXTRA+-- $OVS_EXTRA}
 		OVSINTF=${DEVICE} /sbin/ifup "$OVS_BRIDGE"
 		;;
 	OVSIntPort)
-		/sbin/ifup "$OVS_BRIDGE"
+		ifup_ovs_bridge
 		ovs-vsctl -t ${TIMEOUT} -- --may-exist add-port "$OVS_BRIDGE" "$DEVICE" $OVS_OPTIONS -- set Interface "$DEVICE" type=internal ${OVS_EXTRA+-- $OVS_EXTRA}
 		${OTHERSCRIPT} ${CONFIG} ${2}
 		;;
 	OVSBond)
-		/sbin/ifup "$OVS_BRIDGE"
+		ifup_ovs_bridge
 		for _iface in $BOND_IFACES; do
 			/sbin/ifup ${_iface}
 		done
-- 
2.43.0