Add support for DHCP on bridges (#125259, original patch by Anders Kaseorg

<anders@kaseorg.com>):
- rc.d/init.d/network: Initialize bridges after bridged interfaces,
  deinitialize them before bridged interfaces
- sysconfig/network-scripts/ifdown-eth: Destroy bridges lazily when the last
  bridged interface is stopped
- sysconfig/network-scripts/ifup-eth:
  * Handle bridges before checking for module presence or wireless devices
  * Add bridges lazily when the first bridged interface is started

1 files changed, 19 insertions, 16 deletions

diff --git a/sysconfig/network-scripts/ifup-eth b/sysconfig/network-scripts/ifup-eth
index 5a4a985e..dad0d851 100755
--- a/sysconfig/network-scripts/ifup-eth
+++ b/sysconfig/network-scripts/ifup-eth
@@ -50,27 +50,14 @@ if [ -n "${HWADDR}" ]; then
     fi
 fi
 
-# now check the real state
-is_available ${REALDEVICE} || {
-      if [ -n "$alias" ]; then
-         echo $"$alias device ${DEVICE} does not seem to be present, delaying initialization."
-      else
-         echo $"Device ${DEVICE} does not seem to be present, delaying initialization."
-      fi
-      exit 1
-}
-
-# is the device wireless? If so, configure wireless device specifics
-is_wireless_device ${DEVICE} && . ./ifup-wireless
-
 if [ "${TYPE}" = "Bridge" ]; then
       if [ ! -x /usr/sbin/brctl ]; then
 	  echo $"Bridge support not available: brctl not found"
 	  exit 1
       fi
-      /sbin/ip link set dev ${DEVICE} down 2>/dev/null
-      /usr/sbin/brctl delbr ${DEVICE} 2>/dev/null
-      /usr/sbin/brctl addbr ${DEVICE} 2>/dev/null
+      if ! LC_ALL=C /usr/sbin/brctl show | LC_ALL=C grep -q "^${DEVICE}	"; then
+	  /usr/sbin/brctl addbr ${DEVICE} 2>/dev/null
+      fi
       # brctl doesn't report success/failure (BZ #104408)
       # Test for ourselves whether it worked.
       if ! /usr/sbin/brctl show | LANG=C grep -q "^${DEVICE}	" ; then
@@ -82,7 +69,23 @@ if [ "${TYPE}" = "Bridge" ]; then
       [ -n "${STP}" ] && /usr/sbin/brctl stp ${DEVICE} ${STP}
 fi
 
+# now check the real state
+is_available ${REALDEVICE} || {
+      if [ -n "$alias" ]; then
+         echo $"$alias device ${DEVICE} does not seem to be present, delaying initialization."
+      else
+         echo $"Device ${DEVICE} does not seem to be present, delaying initialization."
+      fi
+      exit 1
+}
+
+# is the device wireless? If so, configure wireless device specifics
+is_wireless_device ${DEVICE} && . ./ifup-wireless
+
 if [ -n "${BRIDGE}" -a -x /usr/sbin/brctl ]; then
+      if ! LC_ALL=C /usr/sbin/brctl show | LC_ALL=C grep -q "^${BRIDGE}	"; then
+	  /usr/sbin/brctl addbr ${BRIDGE} 2>/dev/null
+      fi
       /sbin/ip addr flush dev ${DEVICE} 2>/dev/null
       /sbin/ip link set dev ${DEVICE} up
       /usr/sbin/brctl addif ${BRIDGE} ${DEVICE}