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✏️ Editing: ifup-aliases

#!/bin/bash

#
# configures aliases of device $1
#
# This script goes out of its way to arrive at the configuration of ip
# aliases described in the ifcfg-$DEV:* and ifcfg-$DEV-range* files from
# whatever existing configuration it may be given: existing aliases not
# specified in the configuration will be removed, netmasks and broadcast
# addrs will be updated on existing aliases, and new aliases will be setup.
#
#   range specification files:
#
# One can specify ranges of alised ipaddress using ifcfg-$DEV-range* files.
# Specify multiple ranges using multiple files, such as ifcfg-eth0-range0 and
# ifcfg-eth0-range1, etc. In these files, the following configuration variables 
# specify the range:
#
#    IPADDR_START    -- ipaddr to start range at. eg "192.168.30.1"
#    IPADDR_END      -- ipaddr to end range at. eg "192.168.30.254"
#    CLONENUM_START  -- interface clone number to start using for this range. eg "0"
#
# The above example values create the interfaces eth0:0 through eth0:253 using
# ipaddrs 192.168.30.1 through 192.168.30.254, inclusive.
#
# Other configuration variables such as NETMASK and BROADCAST may be specified
# in the range file and will apply to all of the ipaddresses in the range. Range
# files also inherit configuration from the ifcfg-$DEV file just like normal.
#
# Note that IPADDR_START and IPADR_END are required to be in the same class-c
# block. I.e. IPADDR_START=192.168.30.1 and IPADDR_END=192.168.31.255 is
# not valid.
#
#   speed with large sets of interfaces:
#
# Considerable effort was spent making this script fast. It can efficiently 
# handle a thousand ip aliases on one interface.
# 
# With large sets of ipaddresses the NO_ALIASROUTING=yes configuration is
# highly recommended. (This can be specified in ifcfg-$DEV and inherited.) This
# prevents this script from setting up routing details for the virtual
# interfaces, which I don't think is needed, because outgoing traffic can use the
# main interface. However, make your own conclusions on what you need.
# 
# My test setup of four class C address blocks on a P166 took 25 seconds of 
# which 16 seconds of this was spent in the ifcconfig calls. Without the 
# NO_ALIASROUTING=yes config an additional 12 seconds is spent in route calls.
#
#   notes on internals:
#
# This script uses the bash "eval" command to lookup shell variables with names
# which are generated from other shell variables. This allows us to, in effect,
# create hashes using the shell variable namesspace by just including the hash
# key in the name of the variable.
#
# This script originally written by: David Harris <dharris@drh.net> 
#                                    Principal Engineer, DRH Internet
#                                    June 30, 1999
#
#            modified by: Bill Nottingham <notting@redhat.com>

TEXTDOMAIN=initscripts
TEXTDOMAINDIR=/etc/locale

device=$1
if [ "$device" = "" ]; then
  echo $"usage: ifup-aliases <net-device> [<parent-config>]\n"
  exit 1
fi

PARENTCONFIG=${2:-ifcfg-$device}
parent_device=$device

cd /etc/sysconfig/network-scripts  
. ./network-functions

# Grab the current configuration of any running aliases, place device info
# into variables of the form:
# rdev_<index>_addr = <ip address>
# rdev_<index>_pb = <prefix>_<broadcast>
# rdevip_<ipaddress> = <index>
# Example:
# rdev_0_addr=192.168.1.1
# rdev_0_pb=24_192.16.1.255
# rdevip_192_168_1_1=0
#
# A list of all the devices is created in rdev_LIST.

eval $( ip addr show $device label $device:* | \
    awk 'BEGIN { COUNT=0;LAST_DEV="" } /inet / {
        # Split IP address into address/prefix
        split($2,IPADDR,"/");
        # Create A_B_C_D IP address form
        IP_ADDR=IPADDR[1];
        gsub(/\./,"_",IP_ADDR);
        # Split device into device:index
        split($NF,DEV,":");
        # Update last device
        LAST_DEV=LAST_DEV " " DEV[2];
        printf("rdev_%s_addr=%s\nrdevip_%s=%s\nrdev_%s_pb=%s_%s\nrdev_LIST=\"%s\"\n",
        DEV[2],IPADDR[1],IP_ADDR,DEV[2],DEV[2],IPADDR[2],$4,LAST_DEV);
    } END {
        if(LAST_DEV == "") print "no_devices_are_up=yes"
    }' );

#
# Store configuration of the parent device and network
#

# read from the /etc/sysconfig/network
eval ` (
    . /etc/sysconfig/network;
    echo network_GATEWAY=$GATEWAY\;;
    echo network_GATEWAYDEV=$GATEWAYDEV\;;
) `

# read defaults from the parent config file
[ -f $PARENTCONFIG ] || {
    net_log $"Missing config file $PARENTCONFIG."
    exit 1
}
eval ` (
    . ./$PARENTCONFIG;
    echo default_PREFIX=$PREFIX\;;
    echo default_NETMASK=$NETMASK\;;
    echo default_BROADCAST=$BROADCAST\;;
    echo default_GATEWAY=$GATEWAY\;;
    echo default_NO_ALIASROUTING=$NO_ALIASROUTING\;;
    echo default_ARPCHECK=$ARPCHECK\;;
    echo default_ARPUPDATE=$ARPUPDATE\;;
) `
[ -z "$default_GATEWAY" ] && default_GATEWAY=$network_GATEWAY

function ini_env ()
{
    DEVICE=""
    IPADDR=""
    IPV6ADDR=""
    PREFIX=$default_PREFIX
    NETMASK=$default_NETMASK
    BROADCAST=$default_BROADCAST
    GATEWAY=$default_GATEWAY
    NO_ALIASROUTING=$default_NO_ALIASROUTING
    ONPARENT=""
    ARPCHECK=$default_ARPCHECK
    ARPUPDATE=$default_ARPUPDATE
}

function is_default_gateway ()
{
    LC_ALL=C /sbin/ip route ls default scope global \
        | awk '$3 == "'"$1"'" { found = 1; } END { exit found == 0; }'
}

#
# Read the alias configuration files and enable each aliased
# device using new_interface()
#

function new_interface ()
{

ipa=$IPADDR; ipb=${ipa#*.}; ipc=${ipb#*.};
    IPGLOP="${ipa%%.*}_${ipb%%.*}_${ipc%%.*}_${ipc#*.}";
    DEVNUM=${DEVICE#*:}

MATCH='^[0-9A-Za-z_]*$'
    if (LC_ALL=C; [[ ! "$DEVNUM" =~ $MATCH ]]); then
        net_log $"error in $FILE: invalid alias number"
        return 1
    fi

eval "
        ipseen=\$ipseen_${IPGLOP}; devseen=\$devseen_${DEVNUM};
        ipseen_${IPGLOP}=$FILE; devseen_${DEVNUM}=$FILE;
    ";

if [ -n "$ipseen" ]; then
        net_log $"error in $FILE: already seen ipaddr $IPADDR in $ipseen"
        return 1
    fi

if [ -n "$devseen" ]; then
        net_log $"error in $FILE: already seen device $parent_device:$DEVNUM in $devseen"
        return 1
    fi

if [ -z "$DEVICE" -o -z "$IPADDR" ]; then
        if [ -n "$IPV6ADDR" -a -n "$DEVICE" ] && ! is_false "$IPV6INIT"; then
            /etc/sysconfig/network-scripts/ifup-ipv6 ${DEVICE}
            return $?
        fi
        net_log $"error in $FILE: didn't specify device or ipaddr"
        return 1
    fi

if [ -z "$NETMASK" -a -z "$PREFIX" ]; then
        net_log $"error iN $FILE: didn't specify netmask or prefix"
    fi

if [ -z "$PREFIX" ]; then
        eval $(/bin/ipcalc --prefix ${IPADDR} ${NETMASK})
    fi

if [ -z "$BROADCAST" -o "$BROADCAST" = "$default_BROADCAST" ]; then
        eval $(/bin/ipcalc --broadcast ${IPADDR}/${PREFIX})
    fi

if [ "$no_devices_are_up" = "yes" ]; then
        setup_this=yes
    else

setup_this=""

eval "
        rdev_addr=\$rdev_${DEVNUM}_addr;
        rdev_pb=\$rdev_${DEVNUM}_pb;
        rdev_mark=\$rdev_${DEVNUM}_mark;
        rdevip=\$rdevip_${IPGLOP};
        ";

if [ -n "$rdev_addr" ]; then
            if [ "$rdev_addr" = "${IPADDR}" ]; then
                newmark=keep
                if [ "$rdev_pb" != "${PREFIX}_${BROADCAST}" ]; then
                    setup_this=freshen
                else
                    setup_this=no
                fi
            else
                if [ "$rdev_mark" != "remove" ]; then
                    /sbin/ip addr flush dev $parent_device label $parent_device:${DEVNUM}
                fi
                newmark=remove
                setup_this=yes
            fi
            if [ -n "$rdev_mark" -a "$rdev_mark" != "$newmark" ]; then
                net_log $"error in ifcfg-${parent_device}: files"
                return 1
            fi
            eval " rdev_${DEVNUM}_mark=\$newmark ";
        else
            setup_this=yes
        fi

if [ -n "$rdevip" -a "$rdevip" != "${DEVNUM}" ]; then
            eval " mark_remove=\$rdev_${rdevip}_mark ";
            if [ -n "$mark_remove" -a "$mark_remove" != "remove" ]; then
                net_log $"error in ifcfg-${parent_device}: files"
                return 1
            fi
            if [ "$mark_remove" != "remove" ]; then
                eval " rdev_${rdevip}_mark=remove ";
                /sbin/ip addr flush dev $parent_device label $parent_device:$rdevip
            fi
        fi

if [ "$setup_this" = "freshen" ] ; then
        # we can do the freshen stuff right now
        /sbin/ip addr change ${IPADDR}/${PREFIX} brd ${BROADCAST}
    fi

if [ "$setup_this" = "yes" ] ; then
        if [ "${parent_device}" != "lo" ] &&  [ "${ARPCHECK}" != "no" ] && \
                is_available ${parent_device} && \
                ( grep -qswi "up" /sys/class/net/${parent_device}/operstate ||  grep -qswi "1" /sys/class/net/${parent_device}/carrier ) ; then
            echo $"Determining if ip address ${IPADDR} is already in use for device ${parent_device}..."
            ARPING=$(/sbin/arping -c 2 -w ${ARPING_WAIT:-3} -D -I ${parent_device} ${IPADDR})
            if [ $? = 1 ]; then
                ARPINGMAC=$(echo $ARPING | sed -ne 's/.*\[$.*$\].*/\1/p')
                net_log $"Error, some other host ($ARPINGMAC) already uses address ${IPADDR}."
                return 1
            fi
        fi

/sbin/ip addr add ${IPADDR}/${PREFIX} brd ${BROADCAST} \
            dev ${parent_device} label ${DEVICE}

# update ARP cache of neighboring computers:
        if ! is_false "${ARPUPDATE}" && [ "${REALDEVICE}" != "lo" ]; then
            /sbin/arping -q -A -c 1 -w ${ARPING_UPDATE_WAIT:-3} -I ${parent_device} ${IPADDR}
            ( sleep 2;
            /sbin/arping -q -U -c 1 -w ${ARPING_UPDATE_WAIT:-3} -I ${parent_device} ${IPADDR} ) > /dev/null 2>&1 < /dev/null &
        fi

! is_false "$IPV6INIT" && \
            /etc/sysconfig/network-scripts/ifup-ipv6 ${DEVICE}

if [ "$NO_ALIASROUTING" != yes ]; then

GATEWAYDEV=$network_GATEWAYDEV;

if [ -n "${GATEWAY}" -a \
                    $ -z "${GATEWAYDEV}" -o "${GATEWAYDEV}" = "${DEVICE}" $ ]; then
                # set up default gateway, if it isn't already there
                if ! is_default_gateway "$GATEWAY"; then
                    ip route replace default ${METRIC:+metric $METRIC} via ${GATEWAY} dev ${DEVICE}
                fi
            fi

/etc/sysconfig/network-scripts/ifup-routes ${DEVICE} ${NAME}

ifuplocal_queue="$ifuplocal_queue $DEVICE"
        fi
    fi
}

if [ "$BASH_VERSINFO" ]; then
    shopt -s nullglob
else
    allow_null_glob_expansion=foo
fi

for FILE in ifcfg-${parent_device}:* ; do
    is_ignored_file "$FILE" && continue
    ini_env
    . ./$FILE
    [ -z "$DEVICE" ] && DEVICE=${FILE##ifcfg-}
    [ "$ONPARENT" != "no" -a "$ONPARENT" != "NO" ] && new_interface
    unset DEVICE
done

for FILE in ifcfg-${parent_device}-range* ; do
    is_ignored_file "$FILE" && continue
    ini_env
    . ./$FILE

ipaddr_prefix=${IPADDR_START%.*}
    ipaddr_startnum=${IPADDR_START##*.}
    ipaddr_endnum=${IPADDR_END##*.}

if [ "${IPADDR_START%.*}" != "${IPADDR_END%.*}" ]; then
        net_log $"error in $FILE: IPADDR_START and IPADDR_END don't agree"
        continue
    fi

if [ $ipaddr_startnum -gt $ipaddr_endnum ]; then
        net_log $"error in $FILE: IPADDR_START greater than IPADDR_END"
        continue
    fi

ipaddr_num=$ipaddr_startnum
    ipaddr_clonenum=$CLONENUM_START

while [ $ipaddr_num -le $ipaddr_endnum ]; do
        IPADDR="$ipaddr_prefix.$ipaddr_num"
        DEVICE="$parent_device:$ipaddr_clonenum"
        IPV6INIT="no"
        [ "$ONPARENT" != "no" -a "$ONPARENT" != "NO" ] && new_interface
        ipaddr_num=$(($ipaddr_num+1))
        ipaddr_clonenum=$(($ipaddr_clonenum+1))
    done
done

#
# Remove any devices that should not be around
#
for DEVNUM in $rdev_LIST ; do
    eval " rdev_mark=\$rdev_${DEVNUM}_mark "
    if [ -z "$rdev_mark" ]; then
        /sbin/ip addr flush dev $parent_device label $parent_device:${DEVNUM}
    fi
done

if [ -x /sbin/ifup-local ]; then
    for DEVICE in $ifuplocal_queue ; do
        /sbin/ifup-local ${DEVICE}
    done
fi

MR SKB