Push DNS server from OpenVPN to client on connection

Routers
5

Replacement of the up/down shell script to:

#!/bin/sh

case $script_type in
up)
	i=1
	ns=""
	while true; do
		# As we know, for non-Windows openvpn clients can accept push DHCP
		# options by using a client-side up script which parses the 
		# foreign_option_n environmental variable list
		eval opt=\$foreign_option_${i}
		[ -z "${opt}" ] && break

		ns="$ns\n$(echo ${opt} | sed -e 's/dhcp-option DOMAIN/domain/g' -e 's/dhcp-option DNS/nameserver/g')"

		i=$((i + 1))
	done

	if [ -n "$ns" ]; then
		echo -e "$ns" > /tmp/resolv.conf.vpn
	else
		echo -e "nameserver 209.244.0.3\nnameserver 64.6.64.6" > /tmp/resolv.conf.vpn
	fi

	uci set dhcp.@dnsmasq[0].resolvfile='/tmp/resolv.conf.vpn'
	uci commit dhcp
	# Let it runs on background, in order to avoid any delay to add route table,
	# which will effort to mwan3
	/etc/init.d/dnsmasq restart &
	;;
down)
	# Restore dns
	[ -f "/tmp/resolv.conf.vpn" ] || return 0
	rm -fr "/tmp/resolv.conf.vpn"
	uci set dhcp.@dnsmasq[0].resolvfile='/tmp/resolv.conf.auto'
	uci commit dhcp
	/etc/init.d/dnsmasq restart &
	;;
esac

exit 0