#!/bin/bash # # lc_servip - script for verifying the service IP and the real # interface IP in a remote host are in the same subnet # ############################################################################### # Usage usage() { cat >&2 < service IPaddr the IP address to failover hostname the hostname of the remote node EOF exit 1 } # Check arguments if [ $# -lt 2 ]; then usage fi # Remote command REMOTE=${REMOTE:-"ssh -x -q"} # Check whether the reomte command is pdsh is_pdsh() { if [ "${REMOTE}" = "${REMOTE#*pdsh}" ]; then return 1 fi return 0 } # # inSameIPsubnet serviceIPaddr interfaceIPaddr mask # # Given two IP addresses and a subnet mask determine if these IP # addresses are in the same subnet. If they are, return 0, else return 1. # inSameIPsubnet() { declare -i n declare -ia mask declare -ia ip1 ip2 # IP addresses given declare -i quad1 quad2 # calculated quad words # # Remove '.' characters from dotted decimal notation and save # in arrays. i.e. # # 192.168.1.163 -> array[0] = 192 # array[1] = 168 # array[2] = 1 # array[3] = 163 # let n=0 for quad in $(echo $1 | awk -F. '{print $1 " " $2 " " $3 " " $4}') do ip1[n]=$quad let n=n+1 done let n=0 for quad in $(echo $2 | awk -F. '{print $1 " " $2 " " $3 " " $4}') do ip2[n]=$quad let n=n+1 done let n=0 for quad in $(echo $3 | awk -F. '{print $1 " " $2 " " $3 " " $4}') do mask[n]=$quad let n=n+1 done # # For each quad word, logically AND the IP address with the subnet # mask to get the network/subnet quad word. If the resulting # quad words for both IP addresses are the same they are in the # same IP subnet. # for n in 0 1 2 3 do let $((quad1=${ip1[n]} & ${mask[n]})) let $((quad2=${ip2[n]} & ${mask[n]})) if [ $quad1 != $quad2 ]; then echo >&2 $"`basename $0`: Service IP address $1 and"\ "real interface IP address $2 are in"\ "different subnets!" return 1 # in different subnets fi done return 0 # in the same subnet, all quad words matched } # # findInterface IPaddr hostname # # Given a target IP address and a hostname, find the interface in which # this address is configured. If found return 0, if not return 1. The # interface name is returned to stdout. # findInterface() { declare ret_line declare line declare intf declare addr declare state declare target=$1 declare hostname=$2 while read ret_line do set -- ${ret_line} is_pdsh && shift intf="$1" shift line="$*" while read line do if [ "$line" = "" ]; then # go to next interface continue 2 fi set - $line addr= while [ $# -gt 0 ]; do case $1 in addr:*) addr=${1##addr:} if [ -n "$addr" -a "$addr" = "$target" ] then echo $intf return 0 fi ;; esac shift done done done < <(${REMOTE} $hostname /sbin/ifconfig) echo >&2 "`basename $0`: Cannot find the interface in which" \ "$target is configured in the host $hostname!" return 1 } # # findNetmask interface hostname # # Given an interface find the netmask addresses associated with it. # Return 0 when found, else return 1. The netmask is returned to stdout. # findNetmask() { declare ret_line declare line declare addr declare target=$1 declare hostname=$2 while read ret_line do set -- ${ret_line} is_pdsh && shift line="$*" set - $line while [ $# -gt 0 ]; do case $1 in Mask:*) echo ${1##*:} # return netmask addr return 0 ;; esac shift done done < <(${REMOTE} $hostname /sbin/ifconfig $target) echo >&2 "`basename $0`: Cannot find the netmask associated with" \ "the interface $target in the host $hostname!" return 1 } # # check_srvIPaddr serviceIPaddr hostname # # Given a service IP address and hostname, check whether the service IP address # and the real interface IP address of hostname are in the same subnet. # If they are, return 0, else return 1. # check_srvIPaddr() { declare real_IPaddr declare real_intf declare netmask declare srv_IPaddr=$1 declare hostname=$2 # Get the corresponding IP address of the hostname from /etc/hosts table real_IPaddr=`egrep "[[:space:]]$hostname([[:space:]]|$)" /etc/hosts \ | awk '{print $1}'` if [ -z "$real_IPaddr" ]; then echo >&2 "`basename $0`: Hostname $hostname does not exist in" \ "the local /etc/hosts table!" return 1 fi if [ ${#real_IPaddr} -gt 15 ]; then echo >&2 "`basename $0`: More than one IP address line" \ "corresponding to $hostname in the local" \ "/etc/hosts table!" return 1 fi # Get the interface in which the real IP address is configured real_intf=$(findInterface $real_IPaddr $hostname) if [ $? -ne 0 ]; then return 1 fi real_intf=${real_intf%%:*} # Get the netmask address associated with the real interface netmask=$(findNetmask $real_intf $hostname) if [ $? -ne 0 ]; then return 1 fi # Determine if the service IP address and the real IP address # are in the same subnet inSameIPsubnet $srv_IPaddr $real_IPaddr $netmask if [ $? -ne 0 ]; then return 1 fi return 0 } # Check service IP address if ! check_srvIPaddr $1 $2; then exit 1 fi exit 0