doc: add new primary-backup.sh script for >= 2.6.29

This patch adds a new primary-backup.sh script for Linux kernels
>= 2.6.29. This script takes advantage of the user-space event
reporting that ctnetlink does since this kernel version.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/doc/sync/primary-backup-2.6.29-and-higher.sh b/doc/sync/primary-backup-2.6.29-and-higher.sh
new file mode 100755
index 0000000..3236c24
--- /dev/null
+++ b/doc/sync/primary-backup-2.6.29-and-higher.sh
@@ -0,0 +1,109 @@
+#!/bin/sh
+# 
+# (C) 2008-2009 by Pablo Neira Ayuso <pablo@netfilter.org>
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+#
+# Description:
+#
+# Use this script is you use a Linux kernel >= 2.6.29.
+#
+# This is the script for primary-backup setups for keepalived
+# (http://www.keepalived.org). You may adapt it to make it work with other
+# high-availability managers.
+#
+# Do not forget to include the required modifications to your keepalived.conf
+# file to invoke this script during keepalived's state transitions.
+#
+# Contributions to improve this script are welcome :).
+#
+
+CONNTRACKD_BIN=/usr/sbin/conntrackd
+CONNTRACKD_LOCK=/var/lock/conntrack.lock
+CONNTRACKD_CONFIG=/etc/conntrackd/conntrackd.conf
+
+case "$1" in
+  primary)
+    #
+    # commit the external cache into the kernel table
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -c
+    if [ $? -eq 1 ]
+    then
+        logger "ERROR: failed to invoke conntrackd -c"
+    fi
+
+    #
+    # flush external cache
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -f external
+    if [ $? -eq 1 ]
+    then
+    	logger "ERROR: failed to invoke conntrackd -f external"
+    fi
+    ;;
+
+  backup)
+    #
+    # is conntrackd running? request some statistics to check it
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -s
+    if [ $? -eq 1 ]
+    then
+        #
+	# something's wrong, do we have a lock file?
+	#
+    	if [ -f $CONNTRACKD_LOCK ]
+	then
+	    logger "WARNING: conntrackd was not cleanly stopped."
+	    logger "If you suspect that it has crashed:"
+	    logger "1) Enable coredumps"
+	    logger "2) Try to reproduce the problem"
+	    logger "3) Post the coredump to netfilter-devel@vger.kernel.org"
+	    rm -f $CONNTRACKD_LOCK
+	fi
+	$CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -d
+	if [ $? -eq 1 ]
+	then
+	    logger "ERROR: cannot launch conntrackd"
+	    exit 1
+	fi
+    fi
+    #
+    # shorten kernel conntrack timers to remove the zombie entries.
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -t
+    if [ $? -eq 1 ]
+    then
+    	logger "ERROR: failed to invoke conntrackd -t"
+    fi
+
+    #
+    # request resynchronization with master firewall replica (if any)
+    # Note: this does nothing in the alarm approach.
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -n
+    if [ $? -eq 1 ]
+    then
+    	logger "ERROR: failed to invoke conntrackd -n"
+    fi
+    ;;
+  fault)
+    #
+    # shorten kernel conntrack timers to remove the zombie entries.
+    #
+    $CONNTRACKD_BIN -C $CONNTRACKD_CONFIG -t
+    if [ $? -eq 1 ]
+    then
+    	logger "ERROR: failed to invoke conntrackd -t"
+    fi
+    ;;
+  *)
+    logger "ERROR: unknown state transition"
+    echo "Usage: primary-backup.sh {primary|backup|fault}"
+    exit 1
+    ;;
+esac
+
+exit 0