diff options
Diffstat (limited to 'network-scripts/network-functions')
| -rwxr-xr-x | network-scripts/network-functions | 765 |
1 files changed, 765 insertions, 0 deletions
diff --git a/network-scripts/network-functions b/network-scripts/network-functions new file mode 100755 index 00000000..2d95cfcf --- /dev/null +++ b/network-scripts/network-functions @@ -0,0 +1,765 @@ +# -*-Shell-script-*- +# +# This file is not a stand-alone shell script; it provides functions +# to network scripts that source it. + +# Set up a default search path. +PATH="/sbin:/usr/sbin:/bin:/usr/bin" +export PATH + +# We need to initialize the $HOSTNAME variable by ourselves now: +# (It was previously done for RHEL-6 branch, but got lost in time.) +HOSTNAME="$(hostname)" + +[ -z "$__sed_discard_ignored_files" ] && . /etc/init.d/functions + +RESOLVCONF_FLAGFILE=/var/run/resolvconf/enable-updates + +get_hwaddr () +{ + if [ -f /sys/class/net/${1}/address ]; then + tr '[a-z]' '[A-Z]' < /sys/class/net/${1}/address + elif [ -d "/sys/class/net/${1}" ]; then + LC_ALL= LANG= ip -o link show ${1} 2>/dev/null | \ + awk '{ print toupper(gensub(/.*link\/[^ ]* ([[:alnum:]:]*).*/, + "\\1", 1)); }' + fi +} + +get_config_by_device () +{ + LANG=C grep -l "^[[:space:]]*DEVICE=['\"]\?${1}['\"]\?\([[:space:]#]\|$\)" \ + /etc/sysconfig/network-scripts/ifcfg-* \ + | LC_ALL=C sed -e "$__sed_discard_ignored_files" +} + +get_config_by_hwaddr () +{ + LANG=C grep -il "^[[:space:]]*HWADDR=['\"]\?${1}['\"]\?\([[:space:]#]\|$\)" /etc/sysconfig/network-scripts/ifcfg-* \ + | LC_ALL=C sed -e "$__sed_discard_ignored_files" +} + +get_config_by_subchannel () +{ + LANG=C grep -E -i -l \ + "^[[:space:]]*SUBCHANNELS=['\"]?([0-9]\.[0-9]\.[a-f0-9]+,){0,2}${1}(,[0-9]\.[0-9]\.[a-f0-9]+){0,2}['\"]?([[:space:]]+#|[[:space:]]*$)" \ + /etc/sysconfig/network-scripts/ifcfg-* \ + | LC_ALL=C sed -e "$__sed_discard_ignored_files" +} + +get_config_by_name () +{ + LANG=C grep -E -i -l "^[[:space:]]*NAME=\"(Auto |System )?${1}\"" \ + /etc/sysconfig/network-scripts/ifcfg-* \ + | LC_ALL=C sed -e "$__sed_discard_ignored_files" +} + +get_device_by_hwaddr () +{ + LANG=C ip -o link | awk -F ': ' -vIGNORECASE=1 '!/link\/ieee802\.11/ && /'"$1"'/ { print $2 }' +} + +get_uuid_by_config () +{ + dbus-send --system --print-reply --dest=com.redhat.ifcfgrh1 /com/redhat/ifcfgrh1 com.redhat.ifcfgrh1.GetIfcfgDetails string:"/etc/sysconfig/network-scripts/$1" 2>/dev/null | awk -F '"' '/string / { print $2 }' +} + +generate_lease_file_name () +{ + local ver=$1 + LEASEFILE="/var/lib/dhclient/dhclient$ver-${DEVICE}.leases" + if [ -f $LEASEFILE ]; then + return + fi + LEASEFILE="/var/lib/dhclient/dhclient$ver-${UUID}-${DEVICE}.lease" +} + +generate_config_file_name () +{ + local ver=$1 + if [ -s /etc/dhcp/dhclient$ver-${DEVICE}.conf ]; then + DHCLIENTCONF="-cf /etc/dhcp/dhclient$ver-${DEVICE}.conf"; + elif [ -s /etc/dhclient$ver-${DEVICE}.conf ]; then + DHCLIENTCONF="-cf /etc/dhclient$ver-${DEVICE}.conf"; + else + DHCLIENTCONF=''; + fi +} + +need_config () +{ + local nconfig + + CONFIG="ifcfg-${1}" + [ -f "${CONFIG}" ] && return + CONFIG="${1##*/}" + [ -f "${CONFIG}" ] && return + nconfig=$(get_config_by_name "${1}") + if [ -n "$nconfig" ] && [ -f "$nconfig" ]; then + CONFIG=${nconfig##*/} + return + fi + local addr=$(get_hwaddr ${1}) + if [ -n "$addr" ]; then + nconfig=$(get_config_by_hwaddr ${addr}) + if [ -n "$nconfig" ] ; then + CONFIG=${nconfig##*/} + [ -f "${CONFIG}" ] && return + fi + fi + nconfig=$(get_config_by_device ${1}) + if [ -n "$nconfig" ] && [ -f "$nconfig" ]; then + CONFIG=${nconfig##*/} + return + fi +} + +source_config () +{ + CONFIG=${CONFIG##*/} + DEVNAME=${CONFIG##ifcfg-} + . /etc/sysconfig/network-scripts/$CONFIG + [ -r "keys-$DEVNAME" ] && . /etc/sysconfig/network-scripts/keys-$DEVNAME + case "$TYPE" in + Ethernet) + DEVICETYPE="eth" + ;; + CIPE) + DEVICETYPE="cipcb" + ;; + IPSEC) + DEVICETYPE="ipsec" + ;; + Modem) + DEVICETYPE="ppp" + ;; + xDSL) + DEVICETYPE="ppp" + ;; + ISDN) + DEVICETYPE="ippp" + ;; + Wireless) + DEVICETYPE="eth" + ;; + "Token Ring") + DEVICETYPE="eth" + ;; + CTC) + DEVICETYPE="ctc" + ;; + GRE | GRE6 | IPIP | IPIP6) + DEVICETYPE="tunnel" + ;; + SIT | sit) + DEVICETYPE="sit" + ;; + InfiniBand | infiniband) + DEVICETYPE="ib" + ;; + OVS*) + DEVICETYPE="ovs" + ;; + Bridge) + DEVICETYPE="eth" + ;; + esac + if [ -n "$HWADDR" ]; then + HWADDR=$(tr '[a-z]' '[A-Z]' <<<"$HWADDR") + fi + if [ -n "$MACADDR" ]; then + MACADDR=$(tr '[a-z]' '[A-Z]' <<<"$MACADDR") + fi + [ -z "$DEVICE" -a -n "$HWADDR" ] && DEVICE=$(get_device_by_hwaddr $HWADDR) + [ -z "$DEVICETYPE" ] && DEVICETYPE=$(echo ${DEVICE} | sed "s/[0-9]*$//") + [ -z "$REALDEVICE" -a -n "$PARENTDEVICE" ] && REALDEVICE=$PARENTDEVICE + [ -z "$REALDEVICE" ] && REALDEVICE=${DEVICE%%:*} + [ -z "$SYSCTLDEVICE" ] && SYSCTLDEVICE=${REALDEVICE/.//} + if [ "${DEVICE}" != "${REALDEVICE}" ]; then + ISALIAS=yes + else + ISALIAS=no + fi + if is_nm_running && [ "$REALDEVICE" != "lo" ] ; then + nm_con_load "$CONFIG" + if ! is_false $NM_CONTROLLED; then + UUID=$(get_uuid_by_config $CONFIG) + [ -n "$UUID" ] && _use_nm=true + fi + fi +} + +nm_con_load () { + dbus-send --system --print-reply \ + --dest=org.freedesktop.NetworkManager \ + /org/freedesktop/NetworkManager/Settings \ + org.freedesktop.NetworkManager.Settings.LoadConnections \ + array:string:"/etc/sysconfig/network-scripts/${1}" >/dev/null 2>&1 +} + +ethtool_set() +{ + oldifs=$IFS; + IFS=';'; + if [ -n "${ETHTOOL_DELAY}" ]; then + # Convert microseconds to seconds: + local ETHTOOL_DELAY_SEC=$(convert2sec ${ETHTOOL_DELAY} micro) + sleep ${ETHTOOL_DELAY_SEC} + fi + for opts in $ETHTOOL_OPTS ; do + IFS=$oldifs; + if [[ "${opts}" =~ [[:space:]]*- ]]; then + /sbin/ethtool $opts + else + /sbin/ethtool -s ${REALDEVICE} $opts + fi + IFS=';'; + done + IFS=$oldifs; +} + +expand_config () +{ + local i=0 val + for idx in '' {0..255} ; do + ipaddr[$i]=$(eval echo '$'IPADDR$idx) + if [ -z "${ipaddr[$i]}" ]; then + [ "$idx" ] && [ $idx -ge 2 ] && break + continue + fi + prefix[$i]=$(eval echo '$'PREFIX$idx) + netmask[$i]=$(eval echo '$'NETMASK$idx) + broadcast[$i]=$(eval echo '$'BROADCAST$idx) + arpcheck[$i]=$(eval echo '$'ARPCHECK$idx) + arpupdate[$i]=$(eval echo '$'ARPUPDATE$idx) + + if [ "${prefix[$i]}x" != "x" ]; then + val=$(/bin/ipcalc --netmask "${ipaddr[$i]}/${prefix[$i]}") + netmask[$i]=${val##NETMASK=} + fi + + if [ "${netmask[$i]}x" = "x" ]; then + val=$(/bin/ipcalc --netmask "${ipaddr[$i]}") + netmask[$i]=${val##NETMASK=} + fi + + if [ "${prefix[$i]}x" = "x" ]; then + val=$(/bin/ipcalc --prefix ${ipaddr[$i]} ${netmask[$i]}) + prefix[$i]=${val##PREFIX=} + fi + + if [ "${broadcast[$i]}x" = "x" ]; then + val=$(/bin/ipcalc --broadcast ${ipaddr[$i]} ${netmask[$i]}) + broadcast[$i]=${val##BROADCAST=} + fi + + if [ "${arpcheck[$i]}x" != "x" ]; then + arpcheck[$i]=${arpcheck[$i]##ARPCHECK=} + arpcheck[$i]=${arpcheck[$i],,*} + fi + + if [ "${arpupdate[$i]}x" != "x" ]; then + arpupdate[$i]=${arpupdate[$i]##ARPUPDATE=} + arpupdate[$i]=${arpupdate[$i],,*} + fi + + i=$((i+1)) + done + + [ -n "$DHCP_HOSTNAME" ] && DHCP_HOSTNAME=${DHCP_HOSTNAME%%.*} + + if [ -z "${NETWORK}" ]; then + eval $(/bin/ipcalc --network ${ipaddr[0]} ${netmask[0]}) + fi +} + +toggle_value () +{ + if is_true "$2"; then + echo "$1 on" + elif is_false "$2"; then + echo "$1 off" + else + echo '' + fi +} + +is_nm_running () +{ + dbus-send --system --print-reply \ + --dest=org.freedesktop.DBus \ + /org/freedesktop/DBus \ + org.freedesktop.DBus.GetNameOwner \ + string:"org.freedesktop.NetworkManager" >/dev/null 2>&1 +} + +is_nm_device_unavailable () +{ + [ -x /usr/bin/nmcli ] && \ + LANG=C LC_ALL=C nmcli -t --fields device,state dev status 2>/dev/null | grep -q "^${1}:unavailable$" +} + +is_nm_active () +{ + [ -x /usr/bin/nmcli ] && \ + LANG=C LC_ALL=C nmcli -t --fields device,state dev status 2>/dev/null | grep -q "^${1}:connected$" +} + +is_nm_handling () +{ + [ -x /usr/bin/nmcli ] && \ + LANG=C nmcli -t --fields device,state dev status 2>/dev/null | grep -q "^\(${1}:connected\)\|\(${1}:connecting.*\)$" +} + +is_nm_device_unmanaged () +{ + [ -x /usr/bin/nmcli ] && \ + LANG=C LC_ALL=C nmcli -t --fields GENERAL dev show "${1}" 2>/dev/null | awk -F ':' '/GENERAL.STATE/ { if ($2 == "unmanaged") exit 0 ; else exit 1; }' +} + +# Sets $alias to the device module if $? != 0 +is_available () +{ + [ -z "$1" ] && return 1 + + [ -d "/sys/class/net/$1" ] && return 0 + + [ -n "$BONDING_OPTS" ] && install_bonding_driver $1 + + alias=$(modprobe -c | awk \ + 'BEGIN { alias = ""; } + $1 == "alias" && $2 == "'"$1"'" { alias = $3; } + $1 == "install" { install[$2] = $3; } + END { + cmd = install[alias]; + print alias; + if (alias == "" || alias == "off" || cmd == "/bin/true" || cmd == ":") + exit 1; + exit 0; + } + ') + [ $? -eq 0 ] || return 2 + + modprobe $1 > /dev/null 2>&1 || { + return 1 + } + if [ -n "$HWADDR" ]; then + local curdev=$(get_device_by_hwaddr "$HWADDR") + if [ -z "$curdev" ]; then + return 1 + fi + fi + + if [ ${alias} = "bonding" ]; then + install_bonding_driver $1 + fi + + [ -d "/sys/class/net/$1" ] && return 0 || return 1 +} + +is_available_wait () +{ + [ -z "$1" ] && return 1 + + local retry=${2##*[!0-9]*} + + is_available $1 && return 0 + ret=$? + + while [ 0"$retry" -gt 0 ]; do + sleep 1 + [ -d "/sys/class/net/$1" ] && return 0 + retry=$(($retry -1)) + done + + return $ret +} + +is_hostname_set () +{ + case "${HOSTNAME}" in + '(none)' | 'localhost' | 'localhost.localdomain') + # Hostname NOT set: + return 1 + ;; + *) + # Hostname IS set: + return 0 + ;; + esac +} + +need_hostname () +{ + # Should we avoid obtaining hostname from DHCP? (user override) + is_true "${NO_DHCP_HOSTNAME}" && return 1 + + if is_hostname_set; then + # Hostname is already set, we do not need to acquire it: + return 1 + else + # Hostname is NOT set, we need to acquire it: + return 0 + fi +} + +set_hostname_options () +{ + # User explicitly requires to *not* send DHCP_HOSTNAME, DHCP_FQDN or HOSTNAME: + is_false "${DHCP_SEND_HOSTNAME}" && return + + if [[ -n "${DHCP_HOSTNAME}" && -n "${DHCP_FQDN}" ]]; then + net_log $"Both 'DHCP_HOSTNAME=${DHCP_HOSTNAME}' and 'DHCP_FQDN=${DHCP_FQDN}' are configured... Using DHCP_FQDN." warning + fi + + local hostname_options='' + + # DHCP_FQDN takes precedence before DHCP_HOSTNAME -- as it does in NetworkManager, + # and DHCP_HOSTNAME takes precedence before HOSTNAME: + if [[ -n "${DHCP_FQDN}" ]]; then + hostname_options="-F ${DHCP_FQDN}" + elif [[ -n "${DHCP_HOSTNAME}" ]]; then + hostname_options="-H ${DHCP_HOSTNAME}" + elif is_hostname_set; then + # We need to truncate the hostname in case it is the FQDN: + hostname_options="-H ${HOSTNAME%%.*}" + else + # Nothing to send to the DHCP server: + # ['(none)', 'localhost' or 'localhost.localdomain' are not valid] + return + fi + + # Append the hostname options to the content of passed variable name: + eval "$1='${!1} ${hostname_options}'" + + return +} + +set_hostname () +{ + hostname $1 + if ! grep search /etc/resolv.conf >/dev/null 2>&1; then + domain=$(echo $1 | sed 's/^[^\.]*\.//') + if [ -n "$domain" ]; then + rsctmp=$(mktemp /tmp/XXXXXX); + cat /etc/resolv.conf > $rsctmp + echo "search $domain" >> $rsctmp + + # Backup resolv.conf only if it doesn't exist already: + ! [ -f /etc/resolv.conf.save ] && cp -af /etc/resolv.conf /etc/resolv.conf.save + + change_resolv_conf $rsctmp + /bin/rm -f $rsctmp + fi + fi + if [ -d /etc/sysconfig/network-scripts/hostname.d -a -x /usr/bin/run-parts ]; then + /usr/bin/run-parts --arg $1 /etc/sysconfig/network-scripts/hostname.d + fi +} + +check_device_down () +{ + [ ! -d /sys/class/net/$1 ] && return 0 + if LC_ALL=C ip -o link show dev $1 2>/dev/null | grep -q ",UP" ; then + return 1 + else + return 0 + fi +} + +check_link_down () +{ + if [ "${MII_NOT_SUPPORTED}" = yes ]; then + return 1 + fi + if ! LC_ALL=C ip link show dev $1 2>/dev/null| grep -q ",UP" ; then + ip link set dev $1 up >/dev/null 2>&1 + fi + timeout=0 + delay=10 + [ -n "$LINKDELAY" ] && delay=$(($LINKDELAY * 2)) + while [ $timeout -le $delay ]; do + [ "$(cat /sys/class/net/$REALDEVICE/carrier 2>/dev/null)" != "0" ] && return 1 + sleep 0.5 + timeout=$((timeout+1)) + done + return 0 +} + +check_default_route () +{ + LC_ALL=C ip route list match 0.0.0.0/0 | grep -q default +} + +find_gateway_dev () +{ + . /etc/sysconfig/network + if [ -n "${GATEWAY}" -a "${GATEWAY}" != "none" ] ; then + dev=$(LC_ALL=C /sbin/ip route get to "${GATEWAY}" 2>/dev/null | \ + sed -n 's/.* dev \([[:alnum:]]*\) .*/\1/p') + if [ -n "$dev" ]; then + GATEWAYDEV="$dev" + fi + fi +} + +# After the device $1 goes away, restore the standard default route; typically +# used for ppp with DEFROUTE temporarily replacing the "standard" default +# route. +# FIXME: This function doesn't support some newer features (GATEWAY in ifcfg, +# $WINDOW, $METRIC) +add_default_route () +{ + . /etc/sysconfig/network + check_default_route && return 0 + find_gateway_dev + if [ "$GATEWAYDEV" != "" -a -n "${GATEWAY}" -a \ + "${GATEWAY}" != "none" ]; then + if ! check_device_down $1; then + if [ "$GATEWAY" = "0.0.0.0" ]; then + /sbin/ip route add default dev ${GATEWAYDEV} + else + /sbin/ip route add default via ${GATEWAY} + fi + fi + elif [ -f /etc/default-routes ]; then + while read spec; do + /sbin/ip route add $spec + done < /etc/default-routes + rm -f /etc/default-routes + fi +} + +is_wireless_device () +{ + [ -x /usr/sbin/iw ] || return 1 + LC_ALL=C /usr/sbin/iw dev $1 info > /dev/null 2>&1 && return 0 + return 1 +} + +phy_wireless_device () +{ + cat /sys/class/net/$1/phy80211/name +} + +bond_master_exists () +{ + local bond_name + [ -z "${1}" ] && return 1 + [ ! -f /sys/class/net/bonding_masters ] && return 1 + + for bond_name in $(< /sys/class/net/bonding_masters); do + [ "${bond_name}" == "${1}" ] && return 0 + done + return 1 +} + +install_bonding_driver () +{ + local fn="install_bonding_driver" + + if ! bond_master_exists ${1}; then + modprobe bonding || return 1 + echo "+$1" > /sys/class/net/bonding_masters 2>/dev/null + fi + ( + # Set config here + need_config "$1" + source_config + if [ -f /sys/class/net/${DEVICE}/bonding/slaves ] && [ $(wc -l < /sys/class/net/${DEVICE}/bonding/slaves) -eq 0 ]; then + /sbin/ip link set dev ${DEVICE} down + + # parse options and put them to arrays + for arg in $BONDING_OPTS ; do + bopts_keys[${#bopts_keys[*]}]=${arg%%=*} + bopts_vals[${#bopts_vals[*]}]=${arg##*=} + done + + # add the bits to setup driver parameters here + # first set mode, miimon + for (( idx=0; idx < ${#bopts_keys[*]}; idx++ )) ; do + key=${bopts_keys[$idx]} + value=${bopts_vals[$idx]} + + if [ "${key}" = "mode" ] ; then + echo "${value}" > /sys/class/net/${DEVICE}/bonding/$key || { + net_log $"Failed to set value '$value' [mode] to ${DEVICE} bonding device" err $fn + } + bopts_keys[$idx]="" + fi + if [ "${key}" = "miimon" ] ; then + echo "${value}" > /sys/class/net/${DEVICE}/bonding/$key || { + net_log $"Failed to set value '$value' [miimon] to ${DEVICE} bonding device" err $fn + } + bopts_keys[$idx]="" + fi + done + + # set all other remaining options + for (( idx=0; idx < ${#bopts_keys[*]}; idx++ )) ; do + key=${bopts_keys[$idx]} + value=${bopts_vals[$idx]} + + # option already set; take next + [[ -z "$key" ]] && continue + + if [ "${key}" = "arp_ip_target" -a "${value:0:1}" != "+" ]; then + OLDIFS=$IFS; + IFS=','; + for arp_ip in $value; do + if ! grep -q $arp_ip /sys/class/net/${DEVICE}/bonding/$key; then + echo +$arp_ip > /sys/class/net/${DEVICE}/bonding/$key || { + net_log $"Failed to set '$arp_ip' value [arp_ip_target] to ${DEVICE} bonding device" err $fn + } + fi + done + IFS=$OLDIFS; + elif [ "${key}" = "arp_ip_target" ]; then + if ! grep -q ${value#+} /sys/class/net/${DEVICE}/bonding/$key; then + echo "$value" > /sys/class/net/${DEVICE}/bonding/$key || { + net_log $"Failed to set '$value' value [arp_ip_target] to ${DEVICE} bonding device" err $fn + } + fi + elif [ "${key}" != "primary" ]; then + echo $value > /sys/class/net/${DEVICE}/bonding/$key || { + net_log $"Failed to set '$value' value [$key] to ${DEVICE} bonding device" err $fn + } + fi + done + fi + ) + return 0 +} + +is_bonding_device () +{ + [ -f "/sys/class/net/$1/bonding/slaves" ] +} + +# Invoke this when /etc/resolv.conf has changed: +change_resolv_conf () +{ + oldumask=$(umask) + umask 022 + s=$(/bin/grep '^[\ \ ]*option' /etc/resolv.conf 2>/dev/null) + if [ $# -gt 1 ]; then + if [ "x$s" != "x" ]; then + s="$s"$'\n' + fi + n_args=$# + while [ $n_args -gt 0 ]; do + case "$s" in + *$1*) + shift + n_args=$(($n_args-1)) + continue + ;; + esac + s="$s$1" + shift + if [ $# -gt 0 ]; then + s="$s"$'\n' + fi + n_args=$(($n_args-1)) + done + elif [ $# -eq 1 -a -r "$1" ]; then + if [ "x$s" != "x" ]; then + s="$s"$'\n'$(/bin/grep -vF "$s" $1) + else + s=$(cat $1) + fi + else + return + fi + if [ -e "$RESOLVCONF_FLAGFILE" ]; then + echo "$s" | /sbin/resolvconf -a ${DEVICE} + else + (echo "$s" > /etc/resolv.conf) >/dev/null 2>&1; + fi + r=$? + if [ $r -eq 0 ]; then + [ -x /sbin/restorecon ] && /sbin/restorecon /etc/resolv.conf >/dev/null 2>&1 # reset the correct context + /usr/bin/logger -p local7.notice -t "NET" -i "$0 : updated /etc/resolv.conf" + [ -e /run/nscd/socket ] && /usr/sbin/nscd -i hosts # invalidate cache + fi + umask "$oldumask" + return $r +} + +clear_resolv_conf () +{ + if [ -e "$RESOLVCONF_FLAGFILE" ]; then + /sbin/resolvconf -d ${DEVICE} + elif [ -f /etc/resolv.conf.save ]; then + change_resolv_conf /etc/resolv.conf.save + rm -f /etc/resolv.conf.save + fi +} + +# Logging function +# +# Usage: net_log <message> <err|warning|info> <optional file/function name> +# +# Default level is 'err'. + +net_log() +{ + local message="$1" + local level="$2" + local name="$3" + + [ -z "$message" ] && return 1 + [ -z "$level" ] && level=err + [ -z "$name" ] && name=$0 + + case $level in + 'debug') + local txt_level=$"DEBUG " + ;; + 'err') + local txt_level=$"ERROR " + ;; + 'warning') + local txt_level=$"WARN " + ;; + 'info') + local txt_level=$"INFO " + ;; + esac + + echo "$txt_level: [$name] $message" + + if [ -x /usr/bin/logger ]; then + /usr/bin/logger -p daemon.$level -t "$name" "$message" + fi + return 0 +} + +update_DNS_entries() +{ + # Remove duplicate values from DNS options if any: + if [ -n "${DNS3}" ] && [[ "${DNS3}" == "${DNS2}" || "${DNS3}" == "${DNS1}" ]]; then + unset DNS3 + fi + + if [ -n "${DNS2}" ] && [[ "${DNS2}" == "${DNS1}" ]]; then + unset DNS2 + fi + + # Shift the DNS options if necessary: + if [ -z "${DNS1}" ] && [ -n "${DNS2}" ]; then + DNS1="${DNS2}" + unset DNS2 + fi + + if [ -z "${DNS2}" ] && [ -n "${DNS3}" ]; then + DNS2="${DNS3}" + unset DNS3 + fi + + # We need to check DNS1 again in case only DNS3 was set at all: + if [ -z "${DNS1}" ] && [ -n "${DNS2}" ]; then + DNS1="${DNS2}" + unset DNS2 + fi +} |