use script for setting/deleting system nameservers

1 files changed, 120 insertions, 0 deletions

diff --git a/scripts/vyatta-system-nameservers b/scripts/vyatta-system-nameservers
new file mode 100644
index 00000000..8756bbb6
--- /dev/null
+++ b/scripts/vyatta-system-nameservers
@@ -0,0 +1,120 @@
+#!/bin/bash
+#
+# Module: vyatta-system-nameservers
+#
+# **** License ****
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# This code was originally developed by Vyatta, Inc.
+# Portions created by Vyatta are Copyright (C) 2008 Vyatta, Inc.
+# All Rights Reserved.
+#
+# Author: Mohit Mehta
+# Date: September 2008
+# Description: CLI back-end script for setting/deleting system nameservers
+#
+# **** End License ****
+#
+
+print_usage()
+{
+    echo "Usage:"
+    echo -e "\t$0 update <ip of name-server>"
+    echo -e "\t$0 delete <ip of name-server>"
+}
+
+restart_dnsmasq ()
+{
+  # restart dnsmasq if dns-forwarding is configured
+  if [ -d /opt/vyatta/config/active/service/dns/forwarding ]; then
+     /opt/vyatta/sbin/vyatta-dns-forwarding.pl --update-dnsforwarding >&/dev/null
+  fi
+}
+
+restart_ntp ()
+{
+  # restart ntp if ntp is configured
+  if [ -f /etc/ntp.conf ] && grep -q "^server" /etc/ntp.conf; then
+     /usr/sbin/invoke-rc.d ntp restart >&/dev/null
+  fi
+}
+
+
+update_system_nameservers ()
+{
+  nameserver=$1
+  touch /etc/resolv.conf
+  # if name-server already in /etc/resolv.conf then exit
+  if grep -q "$nameserver\($\|[[:space:]]\)" /etc/resolv.conf; then
+     exit 0
+  else
+  # find last instance of cli inserted nameserver
+  # insert currently received nameserver immediately after that
+  # this is done to keep system set nameservers priority over dhcp received nameservers
+     cli_ns_array=($(awk '{if (!$3) print $2}' /etc/resolv.conf))
+     cli_ns_array_len=${#cli_ns_array[*]}
+     line_num=0
+     if [ $cli_ns_array_len -gt 0 ]; then
+        grepped_ns_line=`grep "${cli_ns_array[$cli_ns_array_len-1]}$" -n /etc/resolv.conf`
+        echo ${grepped_ns_line%%:*} > /etc/resolv_tmp.conf
+        line_num=`cat /etc/resolv_tmp.conf`
+     fi
+     head -$line_num /etc/resolv.conf > /etc/resolv_tmp.conf
+     echo "nameserver      $nameserver" >> /etc/resolv_tmp.conf
+     total_lines=`cat /etc/resolv.conf | wc -l`
+     rest_lines=`expr $total_lines - $line_num`
+     tail -$rest_lines /etc/resolv.conf >> /etc/resolv_tmp.conf
+     mv -f /etc/resolv_tmp.conf /etc/resolv.conf
+  fi
+  restart_dnsmasq
+  restart_ntp
+}
+
+delete_system_nameserver ()
+{
+  nameserver=$1
+  touch /etc/resolv.conf
+  # remove specified nameserver
+  sed -i "/$nameserver$/d" /etc/resolv.conf
+  restart_dnsmasq
+  restart_ntp
+}
+
+
+#
+# main
+#
+
+case "$1" in
+    update)
+        if [ $# -ne 2 ]; then
+                print_usage
+                exit 1
+        fi
+        update_system_nameservers $2
+        exit 0
+        ;;
+
+    delete)
+        if [ $# -ne 2 ]; then
+                print_usage
+                exit 1
+        fi
+        delete_system_nameserver $2
+        exit 0
+        ;;
+
+
+    *)
+        print_usage
+        exit 1
+        ;;
+
+esac