source: freewrt/package/fwifupdown/lib/alias@ 4624b5d

#!/bin/sh
#
# This file is part of the FreeWRT project. FreeWRT is copyrighted
# material, please see the LICENCE file in the top-level directory
# or at http://www.freewrt.org/licence for details.
#
# Christian Fischer <spaetzle@freewrt.org>
#

CFG_PREUP_IFUP_CHECK_OFF=1
CFG_UP_IFUP_CHECK_OFF=1
CFG_DOWN_IFUP_CHECK_OFF=1

iface_type() {
        [ "$(echo $IFACE | sed 's/[^:]*//g')" = ":" ]
}

alias_exists() {
        [ "$(ip a 2>&- | grep $IFACE | sed "s/.*[^${IFACE}]//")" = "$IFACE" ]
}

get_primary() {
        echo $IFACE | sed 's/:.*$//'
}

if_preup() {
        if alias_exists
        then
                mstate 1
                merr "Alias already created, run ifdown $IFACE first"
                return 1
        fi
        is_up $(get_primary) || ifup $(get_primary) || return 1
}

if_up() {
        if alias_exists && is_up $(get_primary)
        then
                mstate 0
        else
                mstate 1
        fi
}

if_down() {
        if ! alias_exists
        then
                mdown
                mstate 1
                merr "Alias doesn't exist, run ifup $IFACE first"
                return 1
        fi

        ### busybox ifdown workaround ###
        # running busybox ifdown <alias interface name> causes primary interface shutdown

        mdown
        ip link set down $IFACE >/dev/null 2>&1
        mstate $?
        builtin exit 1
}

if_postdown() {
:
}

# vim:ts=4