#!/bin/bash

#

# dhclient-script: Network interface configuration script run by

#                  dhclient based on DHCP client communication

#

# Copyright (C) 2008-2014  Red Hat, Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# 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.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#

# Author(s): David Cantrell <dcantrell@redhat.com>

#            Jiri Popelka <jpopelka@redhat.com>

#

# ----------

# This script is a rewrite/reworking on dhclient-script originally

# included as part of dhcp-970306:

# dhclient-script for Linux. Dan Halbert, March, 1997.

# Updated for Linux 2.[12] by Brian J. Murrell, January 1999.

# Modified by David Cantrell <dcantrell@redhat.com> for Fedora and RHEL

# ----------

#

PATH=/bin:/usr/bin:/sbin

# scripts in dhclient.d/ use $SAVEDIR (#833054)

export SAVEDIR=/var/lib/dhclient

LOGFACILITY="local7"

LOGLEVEL="notice"

ETCDIR="/etc/dhcp"

RESOLVCONF="/etc/resolv.conf"

logmessage() {

    msg="${1}"

    logger -p "${LOGFACILITY}.${LOGLEVEL}" -t "NET" "dhclient: ${msg}"

}

eventually_add_hostnames_domain_to_search() {

# For the case when hostname for this machine has a domain that is not in domain_search list

# 1) get a hostname with `ipcalc --hostname` or `hostnamectl --transient`

# 2) get the domain from this hostname

# 3) add this domain to search line in resolv.conf if it's not already

#    there (domain list that we have recently added there is a parameter of this function)

# We can't do this directly when generating resolv.conf in make_resolv_conf(), because

# we need to first save the resolv.conf with obtained values before we can call `ipcalc --hostname`.

# See bug 637763

    search="${1}"

    if need_hostname; then

        status=1

        OLD_HOSTNAME=$HOSTNAME

        if [ -n "${new_ip_address}" ]; then

            eval $(/usr/bin/ipcalc --silent --hostname "${new_ip_address}" ; echo "status=$?")

        elif [ -n "${new_ip6_address}" ]; then

            eval $(/usr/bin/ipcalc --silent --hostname "${new_ip6_address}" ; echo "status=$?")

        fi

        if [ ${status} -eq 0 ]; then

            domain=$(echo "${HOSTNAME}" | cut -s -d "." -f 2-)

        fi

        HOSTNAME=$OLD_HOSTNAME

    else

          domain=$(hostnamectl --transient 2>/dev/null | cut -s -d "." -f 2-)

    fi

    if [ -n "${domain}" ] &&

       [ ! "${domain}" = "localdomain" ] &&

       [ ! "${domain}" = "localdomain6" ] &&

       [ ! "${domain}" = "(none)" ] &&

       [[ ! "${domain}" = *\ * ]]; then

       is_in="false"

       for s in ${search}; do

           if [ "${s}" = "${domain}" ] ||

              [ "${s}" = "${domain}." ]; then

              is_in="true"

           fi

       done

       if [ "${is_in}" = "false" ]; then

           # Add domain name to search list (#637763)

          sed -i -e "s/${search}/${search} ${domain}/" "${RESOLVCONF}"

       fi

    fi

}

make_resolv_conf() {

    [ "${PEERDNS}" = "no" ] && return

    if [ "${reason}" = "RENEW" ] &&

       [ "${new_domain_name}" = "${old_domain_name}" ] &&

       [ "${new_domain_name_servers}" = "${old_domain_name_servers}" ]; then

        return

    fi

    if [ -n "${new_domain_name}" ] ||

       [ -n "${new_domain_name_servers}" ] ||

       [ -n "${new_domain_search}" ]; then

        rscf="$(mktemp "${TMPDIR:-/tmp}/XXXXXX")"

        [[ -z "${rscf}" ]] && return

        echo "; generated by /usr/sbin/dhclient-script" > "${rscf}"

        if [ -n "${SEARCH}" ]; then

            search="${SEARCH}"

        else

            if [ -n "${new_domain_search}" ]; then

                # Remove instaces of \032 (#450042)

                search="${new_domain_search//\\032/ }"

            elif [ -n "${new_domain_name}" ]; then

                # Note that the DHCP 'Domain Name Option' is really just a domain

                # name, and that this practice of using the domain name option as

                # a search path is both nonstandard and deprecated.

                search="${new_domain_name}"

            fi

        fi

        if [ -n "${search}" ]; then

            echo "search ${search}" >> "${rscf}"

        fi

        if [ -n "${RES_OPTIONS}" ]; then

            echo "options ${RES_OPTIONS}" >> "${rscf}"

        fi

        if [ -n "${new_domain_name_servers}" ]; then

            for nameserver in ${new_domain_name_servers} ; do

                echo "nameserver ${nameserver}" >> "${rscf}"

            done

        else # keep 'old' nameservers

            sed -n /^\w*[Nn][Aa][Mm][Ee][Ss][Ee][Rr][Vv][Ee][Rr]/p "${RESOLVCONF}" >> "${rscf}"

        fi

        change_resolv_conf "${rscf}"

        rm -f "${rscf}"

        if [ -n "${search}" ]; then

            eventually_add_hostnames_domain_to_search "${search}"

        fi

    elif [ -n "${new_dhcp6_name_servers}" ] ||

         [ -n "${new_dhcp6_domain_search}" ]; then

        rscf="$(mktemp "${TMPDIR:-/tmp}/XXXXXX")"

        [[ -z "${rscf}" ]] && return

        echo "; generated by /usr/sbin/dhclient-script" > "${rscf}"

        if [ -n "${SEARCH}" ]; then

            search="${SEARCH}"

        else

            if [ -n "${new_dhcp6_domain_search}" ]; then

                search="${new_dhcp6_domain_search//\\032/ }"

            fi

        fi

        if [ -n "${search}" ]; then

            echo "search ${search}" >> "${rscf}"

        fi

        if [ -n "${RES_OPTIONS}" ]; then

            echo "options ${RES_OPTIONS}" >> "${rscf}"

        fi

        shopt -s nocasematch

        if [ -n "${new_dhcp6_name_servers}" ]; then

            for nameserver in ${new_dhcp6_name_servers} ; do

                # If the nameserver has a link-local address

                # add a <zone_id> (interface name) to it.

                if  [[ "$nameserver" =~ ^fe80:: ]]

                then

                    zone_id="%${interface}"

                else

                    zone_id=

                fi

                echo "nameserver ${nameserver}$zone_id" >> "${rscf}"

            done

        else # keep 'old' nameservers

            sed -n /^\w*[Nn][Aa][Mm][Ee][Ss][Ee][Rr][Vv][Ee][Rr]/p "${RESOLVCONF}" >> "${rscf}"

        fi

        shopt -u nocasematch

        change_resolv_conf "${rscf}"

        rm -f "${rscf}"

        if [ -n "${search}" ]; then

            eventually_add_hostnames_domain_to_search "${search}"

        fi

    fi

}

# run given script

run_hook() {

    local script

    local exit_status

    script="${1}"

    if [ -f ${script} ]; then

        . ${script}

    fi

    if [ -n "${exit_status}" ] && [ "${exit_status}" -ne 0 ]; then

        logmessage "${script} returned non-zero exit status ${exit_status}"

    fi

    return ${exit_status}

}

# run scripts in given directory

run_hookdir() {

    local dir

    dir="${1}"

    if [ -d "${dir}" ]; then

        for script in $(find $dir -executable ! -empty); do

            run_hook ${script} || return $?

        done

    fi

    return 0

}

exit_with_hooks() {

    # Source the documented exit-hook script, if it exists

    run_hook "${ETCDIR}/dhclient-exit-hooks" || exit $?

    # Now run scripts in the hooks directory.

    run_hookdir "${ETCDIR}/dhclient-exit-hooks.d" || exit $?

    exit ${1}

}

quad2num() {

    if [ $# -eq 4 ]; then

        let n="${1} << 24 | ${2} << 16 | ${3} << 8 | ${4}"

        echo "${n}"

        return 0

    else

        echo "0"

        return 1

    fi

}

ip2num() {

    IFS='.' quad2num ${1}

}

num2ip() {

    let n="${1}"

    let o1="(${n} >> 24) & 0xff"

    let o2="(${n} >> 16) & 0xff"

    let o3="(${n} >> 8) & 0xff"

    let o4="${n} & 0xff"

    echo "${o1}.${o2}.${o3}.${o4}"

}

get_network_address() {

# get network address for the given IP address and (netmask or prefix)

    ip="${1}"

    nm="${2}"

    if [ -n "${ip}" -a -n "${nm}" ]; then

        if [[ "${nm}" = *.* ]]; then

            ipcalc -s -n "${ip}" "${nm}" | cut -d '=' -f 2

        else

            ipcalc -s -n "${ip}/${nm}" | cut -d '=' -f 2

        fi

    fi

}

get_prefix() {

# get prefix for the given IP address and mask

    ip="${1}"

    nm="${2}"

    if [ -n "${ip}" -a -n "${nm}" ]; then

        ipcalc -s -p "${ip}" "${nm}" | cut -d '=' -f 2

    fi

}

class_bits() {

    let ip=$(IFS='.' ip2num "${1}")

    let bits=32

    let mask='255'

    for ((i=0; i <= 3; i++, 'mask<<=8')); do

        let v='ip&mask'

        if [ "$v" -eq 0 ] ; then

             let bits-=8

        else

             break

        fi

    done

    echo $bits

}

is_router_reachable() {

    # handle DHCP servers that give us a router not on our subnet

    router="${1}"

    routersubnet="$(get_network_address "${router}" "${new_subnet_mask}")"

    mysubnet="$(get_network_address "${new_ip_address}" "${new_subnet_mask}")"

    if [ ! "${routersubnet}" = "${mysubnet}" ]; then

        # TODO: This function should not have side effects such as adding or

        # removing routes. Can this be done with "ip route get" or similar

        # instead? Are there cases that rely on this route being created here?

        ip -4 route replace "${router}/32" dev "${interface}"

        if [ "$?" -ne 0 ]; then

            logmessage "failed to create host route for ${router}"

            return 1

        fi

    fi

    return 0

}

add_default_gateway() {

    router="${1}"

    if is_router_reachable "${router}" ; then

        if [ $# -gt 1 ] && [ -n "${2}" ] && [[ "${2}" -gt 0 ]]; then

            ip -4 route replace default via "${router}" dev "${interface}" metric "${2}"

        else

            ip -4 route replace default via "${router}" dev "${interface}"

        fi

        if [ $? -ne 0 ]; then

            logmessage "failed to create default route: ${router} dev ${interface} ${metric}"

            return 1

        else

            return 0

        fi

    fi

    return 1

}

execute_client_side_configuration_scripts() {

# execute any additional client side configuration scripts we have

    if [ "${1}" == "config" ] || [ "${1}" == "restore" ]; then

        for f in ${ETCDIR}/dhclient.d/*.sh ; do

            if [ -x "${f}" ]; then

                subsystem="${f%.sh}"

                subsystem="${subsystem##*/}"

                . "${f}"

                "${subsystem}_${1}"

            fi

        done

    fi

}

flush_dev() {

# Instead of bringing the interface down (#574568)

# explicitly clear ARP cache and flush all addresses & routes.

    ip -4 addr flush dev "${1}" >/dev/null 2>&1

    ip -4 route flush dev "${1}" >/dev/null 2>&1

    ip -4 neigh flush dev "${1}" >/dev/null 2>&1

}

remove_old_addr() {

    if [ -n "${old_ip_address}" ]; then

        if [ -n "${old_prefix}" ]; then

            ip -4 addr del "${old_ip_address}/${old_prefix}" dev "${interface}" >/dev/null 2>&1

        else

            ip -4 addr del "${old_ip_address}" dev "${interface}" >/dev/null 2>&1

        fi

    fi

}

dhconfig() {

    if [ -n "${old_ip_address}" ] && [ -n "${alias_ip_address}" ] &&

       [ ! "${alias_ip_address}" = "${old_ip_address}" ]; then

        # possible new alias, remove old alias first

        ip -4 addr del "${old_ip_address}" dev "${interface}" label "${interface}:0"

    fi

    if [ -n "${old_ip_address}" ] &&

       [ ! "${old_ip_address}" = "${new_ip_address}" ]; then

        # IP address changed. Delete all routes, and clear the ARP cache.

        flush_dev "${interface}"

    fi

    # make sure the interface is up

    ip link set dev "${interface}" up

    # replace = add if it doesn't exist or override (update lifetimes) if it's there

    ip -4 addr replace "${new_ip_address}/${new_prefix}" broadcast "${new_broadcast_address}" dev "${interface}" \

       valid_lft "${new_dhcp_lease_time}" preferred_lft "${new_dhcp_lease_time}" >/dev/null 2>&1

    if [ "${reason}" = "BOUND" ] || [ "${reason}" = "REBOOT" ] ||

       [ ! "${old_ip_address}" = "${new_ip_address}" ] ||

       [ ! "${old_subnet_mask}" = "${new_subnet_mask}" ] ||

       [ ! "${old_network_number}" = "${new_network_number}" ] ||

       [ ! "${old_broadcast_address}" = "${new_broadcast_address}" ] ||

       [ ! "${old_routers}" = "${new_routers}" ] ||

       [ ! "${old_interface_mtu}" = "${new_interface_mtu}" ]; then

        # The 576 MTU is only used for X.25 and dialup connections

        # where the admin wants low latency.  Such a low MTU can cause

        # problems with UDP traffic, among other things.  As such,

        # disallow MTUs from 576 and below by default, so that broken

        # MTUs are ignored, but higher stuff is allowed (1492, 1500, etc).

        if [ -n "${new_interface_mtu}" ] && [ "${new_interface_mtu}" -gt 576 ]; then

            ip link set dev "${interface}" mtu "${new_interface_mtu}"

        fi

        # static routes

        if [ -n "${new_classless_static_routes}" ] ||

           [ -n "${new_static_routes}" ]; then

            if [ -n "${new_classless_static_routes}" ]; then

                IFS=', |' static_routes=(${new_classless_static_routes})

                # If the DHCP server returns both a Classless Static Routes option and

                # a Router option, the DHCP client MUST ignore the Router option. (RFC3442)

                new_routers=""

            else

                IFS=', |' static_routes=(${new_static_routes})

            fi

            route_targets=()

            for((i=0; i<${#static_routes[@]}; i+=2)); do

                target=${static_routes[$i]}

                if [ -n "${new_classless_static_routes}" ]; then

                    if [ "${target}" = "0" ]; then

                        new_routers="${static_routes[$i+1]}"

                        continue

                    else

                        prefix=${target%%.*}

                        target=${target#*.}

                        IFS="." target_arr=(${target})

                        unset IFS

                        ((pads=4-${#target_arr[@]}))

                        for j in $(seq $pads); do

                            target="${target}.0"

                        done

                        # Client MUST zero any bits in the subnet number where the corresponding bit in the mask is zero.

                        # In other words, the subnet number installed in the routing table is the logical AND of

                        # the subnet number and subnet mask given in the Classless Static Routes option. (RFC3442)

                        target="$(get_network_address "${target}" "${prefix}")"

                    fi

                else

                    prefix=$(class_bits "${target}")

                fi

                gateway=${static_routes[$i+1]}

                # special case 0.0.0.0 to allow static routing for link-local addresses

                # (including IPv4 multicast) which will not have a next-hop (#769463, #787318)

                if [ "${gateway}" = "0.0.0.0" ]; then

                    valid_gateway=0

                    scope='scope link'

                else

                    is_router_reachable "${gateway}"

                    valid_gateway=$?

                    scope=''

                fi

                if [ "${valid_gateway}" -eq 0 ]; then

                    metric=''

                    for t in "${route_targets[@]}"; do

                        if [ "${t}" = "${target}" ]; then

                            if [ -z "${metric}" ]; then

                                metric=1

                            else

                                ((metric=metric+1))

                            fi

                        fi

                    done

                    if [ -n "${metric}" ]; then

                        metric="metric ${metric}"

                    fi

                    ip -4 route replace "${target}/${prefix}" proto static via "${gateway}" dev "${interface}" ${metric} ${scope}

                    if [ $? -ne 0 ]; then

                        logmessage "failed to create static route: ${target}/${prefix} via ${gateway} dev ${interface} ${metric}"

                    else

                        route_targets=(${route_targets[@]} ${target})

                    fi

                fi

            done

        fi

        # gateways

        if [[ ( "${DEFROUTE}" != "no" ) &&

              (( -z "${GATEWAYDEV}" ) || ( "${GATEWAYDEV}" = "${interface}" )) ]]; then

            if [[ ( -z "${GATEWAY}" ) ||

                  (( -n "${DHCLIENT_IGNORE_GATEWAY}" ) && ( "${DHCLIENT_IGNORE_GATEWAY}" = [Yy]* )) ]]; then

                metric="${METRIC:-}"

                let i="${METRIC:-0}"

                default_routers=()

                for router in ${new_routers} ; do

                    added_router=-

                    for r in "${default_routers[@]}" ; do

                        if [ "${r}" = "${router}" ]; then

                            added_router=1

                        fi

                    done

                    if [ -z "${router}" ] ||

                       [ "${added_router}" = "1" ] ||

                       [ "$(IFS='.' ip2num ${router})" -le 0 ] ||

                       [[ ( "${router}" = "${new_broadcast_address}" ) &&

                          ( "${new_subnet_mask}" != "255.255.255.255" ) ]]; then

                        continue

                    fi

                    default_routers=(${default_routers[@]} ${router})

                    add_default_gateway "${router}" "${metric}"

                    let i=i+1

                    metric=${i}

                done

            elif [ -n "${GATEWAY}" ]; then

                routersubnet=$(get_network_address "${GATEWAY}" "${new_subnet_mask}")

                mysubnet=$(get_network_address "${new_ip_address}" "${new_subnet_mask}")

                if [ "${routersubnet}" = "${mysubnet}" ]; then

                    ip -4 route replace default via "${GATEWAY}" dev "${interface}"

                fi

            fi

        fi

    fi

    if [ ! "${new_ip_address}" = "${alias_ip_address}" ] &&

       [ -n "${alias_ip_address}" ]; then

        # Reset the alias address (fix: this should really only do this on changes)

        ip -4 addr flush dev "${interface}" label "${interface}:0" >/dev/null 2>&1

        ip -4 addr replace "${alias_ip_address}/${alias_prefix}" broadcast "${alias_broadcast_address}" dev "${interface}" label "${interface}:0"

        ip -4 route replace "${alias_ip_address}/32" dev "${interface}"

    fi

    # After dhclient brings an interface UP with a new IP address, subnet mask, 

    # and routes, in the REBOOT/BOUND states -> search for "dhclient-up-hooks".

    if [ "${reason}" = "BOUND" ] || [ "${reason}" = "REBOOT" ] ||

       [ ! "${old_ip_address}" = "${new_ip_address}" ] ||

       [ ! "${old_subnet_mask}" = "${new_subnet_mask}" ] ||

       [ ! "${old_network_number}" = "${new_network_number}" ] ||

       [ ! "${old_broadcast_address}" = "${new_broadcast_address}" ] ||

       [ ! "${old_routers}" = "${new_routers}" ] ||

       [ ! "${old_interface_mtu}" = "${new_interface_mtu}" ]; then

        if [ -x "${ETCDIR}/dhclient-${interface}-up-hooks" ]; then

            . "${ETCDIR}/dhclient-${interface}-up-hooks"

        elif [ -x ${ETCDIR}/dhclient-up-hooks ]; then

            . ${ETCDIR}/dhclient-up-hooks

        fi

    fi

    make_resolv_conf

    if [ -n "${new_host_name}" ] && need_hostname; then

        hostnamectl set-hostname --transient --no-ask-password "${new_host_name}"

    fi

    if [[ ( "${DHCP_TIME_OFFSET_SETS_TIMEZONE}" = [yY1]* ) &&

          ( -n "${new_time_offset}" ) ]]; then

        # DHCP option "time-offset" is requested by default and should be

        # handled.  The geographical zone abbreviation cannot be determined

        # from the GMT offset, but the $ZONEINFO/Etc/GMT$offset file can be

        # used - note: this disables DST.

        ((z=new_time_offset/3600))

        ((hoursWest=$(printf '%+d' $z)))

        if (( $hoursWest < 0 )); then

            # tzdata treats negative 'hours west' as positive 'gmtoff'!

            ((hoursWest*=-1))

        fi

        tzfile=/usr/share/zoneinfo/Etc/GMT$(printf '%+d' ${hoursWest})

        if [ -e "${tzfile}" ]; then

            cp -fp "${tzfile}" /etc/localtime

            touch /etc/localtime

        fi

    fi

    execute_client_side_configuration_scripts "config"

}

wait_for_link_local() {

    # we need a link-local address to be ready (not tentative)

    for i in $(seq 50); do

        linklocal=$(ip -6 addr show dev "${interface}" scope link)

        # tentative flag means DAD is still not complete

        tentative=$(echo "${linklocal}" | grep tentative)

        [[ -n "${linklocal}" && -z "${tentative}" ]] && exit_with_hooks 0

        sleep 0.1

    done

}

# Section 18.1.8. (Receipt of Reply Messages) of RFC 3315 says:

# The client SHOULD perform duplicate address detection on each of

# the addresses in any IAs it receives in the Reply message before

# using that address for traffic.

add_ipv6_addr_with_DAD() {

            ip -6 addr replace "${new_ip6_address}/${new_ip6_prefixlen}" \

                dev "${interface}" scope global valid_lft "${new_max_life}" \

                                          preferred_lft "${new_preferred_life}"

            # repeatedly test whether newly added address passed

            # duplicate address detection (DAD)

            for i in $(seq 5); do

                sleep 1 # give the DAD some time

                addr=$(ip -6 addr show dev "${interface}" \

                       | grep "${new_ip6_address}/${new_ip6_prefixlen}")

                # tentative flag == DAD is still not complete

                tentative=$(echo "${addr}" | grep tentative)

                # dadfailed flag == address is already in use somewhere else

                dadfailed=$(echo "${addr}" | grep dadfailed)

                if [ -n "${dadfailed}" ] ; then

                    # address was added with valid_lft/preferred_lft 'forever', remove it

                    ip -6 addr del "${new_ip6_address}/${new_ip6_prefixlen}" dev "${interface}"

                    exit_with_hooks 3

                fi

                if [ -z "${tentative}" ] ; then

                    if [ -n "${addr}" ]; then

                        # DAD is over

                        return 0

                    else

                        # address was auto-removed (or not added at all)

                        exit_with_hooks 3

                    fi

                fi

            done

            return 0

}

dh6config() {

    if [ -n "${old_ip6_prefix}" ] ||

       [ -n "${new_ip6_prefix}" ]; then

        echo "Prefix ${reason} old=${old_ip6_prefix} new=${new_ip6_prefix}"

        exit_with_hooks 0

    fi

    case "${reason}" in

        BOUND6)

            if [ -z "${new_ip6_address}" ] ||

               [ -z "${new_ip6_prefixlen}" ]; then

                exit_with_hooks 2

            fi

            add_ipv6_addr_with_DAD

            make_resolv_conf

            ;;

        RENEW6|REBIND6)

            if [[ -n "${new_ip6_address}" ]] &&

               [[ -n "${new_ip6_prefixlen}" ]]; then

               if [[  ! "${new_ip6_address}" = "${old_ip6_address}" ]]; then

                   [[ -n "${old_ip6_address}" ]] && ip -6 addr del "${old_ip6_address}" dev "${interface}"

               fi

               # call it even if new_ip6_address = old_ip6_address to update lifetimes

               add_ipv6_addr_with_DAD

            fi

            if [ ! "${new_dhcp6_name_servers}" = "${old_dhcp6_name_servers}" ] ||

               [ ! "${new_dhcp6_domain_search}" = "${old_dhcp6_domain_search}" ]; then

                make_resolv_conf

            fi

            ;;

        DEPREF6)

            if [ -z "${new_ip6_prefixlen}" ]; then

                exit_with_hooks 2

            fi

            ip -6 addr change "${new_ip6_address}/${new_ip6_prefixlen}" \

                dev "${interface}" scope global preferred_lft 0

            ;;

    esac

    execute_client_side_configuration_scripts "config"

}

# Functions from /etc/sysconfig/network-scripts/network-functions

need_hostname ()

{

    CHECK_HOSTNAME=$(hostnamectl --transient)

    if [[ "${CHECK_HOSTNAME}" = "(none)" ]] ||

       [[ "${CHECK_HOSTNAME}" = "localhost" ]] ||

       [[ "${CHECK_HOSTNAME}" = "localhost.localdomain" ]]; then

        return 0

    else

        return 1

    fi

}

# Takes one argument - temporary resolv.conf file

change_resolv_conf ()

{

    options=$(grep '^[\ \	]*option' "${RESOLVCONF}" 2>/dev/null);

    if [[ -n "${options}" ]]; then

       # merge options from existing resolv.conf with specified resolv.conf content

       newres="${options}"$'\n'$(grep -vF "${options}" "${1}");

    else

       newres=$(cat "${1}");

    fi;

    eval $(echo "${newres}" > "${RESOLVCONF}"; echo "status=$?")

    if [[ $status -eq 0 ]]; then

        logger -p local7.notice -t "NET" -i "${0} : updated ${RESOLVCONF}";

        [[ -e /var/run/nscd/socket ]] && /usr/sbin/nscd -i hosts; # invalidate cache

    fi;

    return $status;

}

get_config_by_name ()

{

    LANG=C grep -E -i -l \

        "^[[:space:]]*NAME=\"(Auto |System )?${1}\"" \