From bafc4d1f7971edbe7cd411fbe2ee6876ded35c6e Mon Sep 17 00:00:00 2001
From: Allain Legacy <allain.legacy@windriver.com>
Date: Thu, 14 Apr 2016 12:04:55 -0400
Subject: [PATCH] CGTS-3416: dhclient: restrict interfaces to those on command
 line only

By default, the dhclient process does not respect the list of interfaces
supplied at the command line.  It configures any interfaces found to be
specified in the config file.  Since we customize options for each interface in
our config file and run a separate dhclient process for each interface we end
up with multiple dhclient processes that each service all interfaces.  This is
undesirable because it is possible that a request is sent by process A but
received by process B.  This leads to lease expiry events even though a valid
request packet was returned by the server.

This change introduces a "--restrict-interfaces" option to the dhclient process
to force it to ignore all interfaces in config files other than those specified
at the command line.

To activate this change our version of ifup/ifdown has been modified to
pass the "--restrict-interfaces" to dhclient as well as to request that each
process use its own lease file to avoid file corruption.
---
 sysconfig/network-scripts/ifdown-eth | 2 +-
 sysconfig/network-scripts/ifup-eth   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/sysconfig/network-scripts/ifdown-eth b/sysconfig/network-scripts/ifdown-eth
index 7ccbddf..5b75162 100755
--- a/sysconfig/network-scripts/ifdown-eth
+++ b/sysconfig/network-scripts/ifdown-eth
@@ -92,7 +92,7 @@ for VER in "" 6 ; do
         dhcpid=$(cat /var/run/dhclient$VER-${DEVICE}.pid)
         generate_lease_file_name $VER
         if is_true "$DHCPRELEASE";  then
-            /sbin/dhclient -r -lf ${LEASEFILE} -pf /var/run/dhclient$VER-${DEVICE}.pid ${DEVICE} >/dev/null 2>&1
+            /sbin/dhclient -r -lf ${LEASEFILE} --restrict-interfaces -pf /var/run/dhclient$VER-${DEVICE}.pid ${DEVICE} >/dev/null 2>&1
             retcode=$?
         else
             kill $dhcpid >/dev/null 2>&1
diff --git a/sysconfig/network-scripts/ifup-eth b/sysconfig/network-scripts/ifup-eth
index 3da5c16..9bcf57f 100755
--- a/sysconfig/network-scripts/ifup-eth
+++ b/sysconfig/network-scripts/ifup-eth
@@ -204,7 +204,7 @@ if [ -n "${DYNCONFIG}" ] && [ -x /sbin/dhclient ]; then
     generate_lease_file_name

     # Initialize the dhclient args and obtain the hostname options if needed:
-    DHCLIENTARGS="${DHCLIENTARGS} ${ONESHOT} -q ${DHCLIENTCONF} -lf ${LEASEFILE} -pf /var/run/dhclient-${DEVICE}.pid"
+    DHCLIENTARGS="${DHCLIENTARGS} ${ONESHOT} -q ${DHCLIENTCONF} -lf ${LEASEFILE} --restrict-interfaces -pf /var/run/dhclient-${DEVICE}.pid"
     set_hostname_options DHCLIENTARGS

     echo
@@ -355,7 +355,7 @@ if is_true "${DHCPV6C}" && [ -x /sbin/dhclient ]; then
     echo -n $"Determining IPv6 information for ${DEVICE}..."

     # Initialize the dhclient args for IPv6 and obtain the hostname options if needed:
-    DHCLIENTARGS="-6 -1 ${DHCPV6C_OPTIONS} ${DHCLIENTCONF} -lf ${LEASEFILE} -pf /var/run/dhclient6-${DEVICE}.pid ${DEVICE}"
+    DHCLIENTARGS="-6 -1 ${DHCPV6C_OPTIONS} ${DHCLIENTCONF} -lf ${LEASEFILE} --restrict-interfaces -pf /var/run/dhclient6-${DEVICE}.pid ${DEVICE}"
     set_hostname_options DHCLIENTARGS

     if /sbin/dhclient $DHCLIENTARGS; then
--
1.9.1