iopsys-feed/netmode/files/sbin/netmode-discover

#!/bin/sh

mask_to_cidr() {
    nbits=0
    IFS=.
    for dec in $1 ; do
        case $dec in
            255) let nbits+=8;;
            254) let nbits+=7;;
            252) let nbits+=6;;
            248) let nbits+=5;;
            240) let nbits+=4;;
            224) let nbits+=3;;
            192) let nbits+=2;;
            128) let nbits+=1;;
            0);;
            *) echo "Error: $dec is not recognised"; exit 1
        esac
    done
    echo "$nbits"
}

while true; do
	[ -e /sys/class/net/br-wan ] || {
		sleep 5
		continue
	}

	unlisted=0

	ps | grep wifi | grep -q reload || {
		for mac in $(brctl showmacs br-wan 2>/dev/null | tail -n +2 | grep no | awk '{print$2}'); do
			grep -q "$mac" /proc/net/arp || unlisted=$((unlisted+1))
		done

		ipaddr=$(ifconfig br-wan | grep -v inet6 | grep inet | tr ':' ' ' | awk '{print$3}')
		netmask=$(ifconfig br-wan | grep -v inet6 | grep inet | tr ':' ' ' | awk '{print$7}')
		mask=$(mask_to_cidr $netmask)
	}

	if [ $unlisted -gt 0 -a -n "$ipaddr" -a -n "$netmask" -a $mask -ge 24 ]; then
		fping -c 1 -t 1000 -g $ipaddr/$mask -q >/dev/null 2>&1
	fi

	sleep 30
done