source: freewrt/package/base-files/default/usr/share/udhcpc/default.script@ 15d8ea1

#!/bin/sh
[ -z "$1" ] && echo "Error: should be run by udhcpc" && exit 1

RESOLV_CONF="/tmp/resolv.conf"

hotplug_event() {
        nvram show 2>&- | grep _proto=dhcp | {
                while :; do
                        read FOO
                        [ -z "$FOO" ] && break
                        FOO="${FOO%%_*}"
                        [ "$(nvram get ${FOO}_ifname)" = "${interface}" ] || continue
                        env -i ACTION="$1" INTERFACE="${FOO}" PROTO=dhcp /sbin/hotplug iface
                done
        }
}

case "$1" in
        deconfig)
                ifconfig $interface 0.0.0.0
                hotplug_event ifdown
        ;;
        renew|bound)
                ifconfig $interface $ip \
                netmask ${subnet:-255.255.255.0} \
                broadcast ${broadcast:-+}

                if [ -n "$router" ] ; then
                        echo "deleting routers"
                        while route del default gw 0.0.0.0 dev $interface >&- 2>&- ; do :; done
                                        
                        for i in $router ; do
                                echo "adding router $i"
                                route add default gw $i dev $interface
                        done
                fi

                echo -n > $RESOLV_CONF
                ${domain:+echo search $domain} >> $RESOLV_CONF
                for i in $dns ; do
                        echo "adding dns $i"
                        echo "nameserver $i" >> $RESOLV_CONF
                done
                
                hotplug_event ifup
                
                # user rules
                [ -f /etc/udhcpc.user ] && . /etc/udhcpc.user
        ;;
esac

exit 0