source: bootscripts-standard/bootscripts/clfs/sysconfig/network-devices/ifup@ 94bfdfa

#!/bin/bash
########################################################################
# Begin $network_devices/ifup
#
# Description : Interface Up
#
# Authors     : Nathan Coulson - nathan@linuxfromscratch.org
#               Kevin P. Fleming - kpfleming@linuxfromscratch.org
#
# Version     : 00.00
#
# Notes       : the IFCONFIG variable is passed to the scripts found
#               in the services directory, to indicate what file the
#               service should source to get environmental variables.
#
########################################################################

. /etc/sysconfig/rc 
. ${rc_functions} 

# Collect a list of configuration files for our interface
if [ -n "${2}" ]; then
        for file in ${@#$1} # All parameters except $1
  do
                FILES="${FILES} ${network_devices}/ifconfig.${1}/${file}"
        done
elif [ -d "${network_devices}/ifconfig.${1}" ]; then
        FILES=`echo ${network_devices}/ifconfig.${1}/*`
else 
        FILES="${network_devices}/ifconfig.${1}"
fi

boot_mesg "Bringing up the ${1} interface..."
boot_mesg_flush

# Process each configuration file
for file in ${FILES}; do
        # skip backup files
        if [ "${file}" != "${file%""~""}" ]; then
                continue
        fi

        if [ ! -f "${file}" ]; then
                boot_mesg "${file} is not a network configuration file or directory." ${WARNING}
                echo_warning
                continue
        fi

        (
                . ${file}

                # Will not process this service if started by boot, and ONBOOT
                # is not set to yes
                if [ "${IN_BOOT}" = "1" -a "${ONBOOT}" != "yes" ]; then
                        continue
                fi
                # Will not process this service if started by hotplug, and 
                # ONHOTPLUG is not set to yes
                if [ "${IN_HOTPLUG}" = "1" -a "${ONHOTPLUG}" != "yes" -a "${HOSTNAME}" != "(none)" ]; then
                         continue
                fi

                # This will allow us to assign subinterfaces to our primary
                if [ "${INTERFACE}" != "" ]; then
                        NET_IF=${INTERFACE}
                else
                        NET_IF=${1}
                fi

                if [ -n "${SERVICE}" -a -x "${network_devices}/services/${SERVICE}" ]; then
                        if [ -z "${CHECK_LINK}" -o "${CHECK_LINK}" = "y" -o "${CHECK_LINK}" = "yes" -o "${CHECK_LINK}" = "1" ]; then
                                TEST="`ip addr show ${NET_IF} | grep inet | grep ${NET_IF} | cut -f1 -d'/' | cut -f2 -d't' | cut -f2 -d' '`"
                                if [ "$TEST" != "" ]; then
                                                boot_mesg "Interface ${NET_IF} already configured with IP ${TEST}." ${WARNING}
                                                echo_warning
                                                continue
                                else
                                        if ip link show ${NET_IF} > /dev/null 2>&1; then
                                                link_status=`ip link show ${NET_IF} 2> /dev/null | grep ${NET_IF}`
                                                if [ -n "${link_status}" ]; then
                                                        if ! echo "${link_status}" | grep -q UP; then
                                                                ip link set ${NET_IF} up
                                                        fi
                                                fi
                                        else
                                                boot_mesg "Interface ${NET_IF} doesn't exist." ${WARNING}
                                                echo_warning
                                                continue
                                        fi
                                fi
                        fi
                        IFCONFIG=${file} ${network_devices}/services/${SERVICE} ${NET_IF} up
                else
                        boot_mesg "Unable to process ${file}.  Either" ${FAILURE}
                        boot_mesg " the SERVICE variable was not set,"
                        boot_mesg " or the specified service cannot be executed."
                        echo_failure
                        continue
                fi
        )
done

# End $network_devices/ifup