#!/bin/bash

_DetermineMyLANIP() {
	(
		. /var/lib/dhcpcd/dhcpcd-"${UPnP_LAN_Interface}".info
		echo "${IPADDR}"
	)
}

_DetermineRouterLANIP() {
	(
		. /var/lib/dhcpcd/dhcpcd-"${UPnP_LAN_Interface}".info
		read IP xtra <<<"${GATEWAYS}"
		echo "${IP}"
	)
}

UPnP_EnsureURI() {
	[ -n "${UPnP_URI}" ] && return
	[ -z "${UPnP_RouterHost}" ] &&
		UPnP_RouterHost="$(_DetermineRouterLANIP)"
	[ -z "${UPnP_RouterHost}" ] &&
		return # No idea, give up!
	UPnP_URI="http://${UPnP_RouterHost}/UD/?3"
}

UPnP_PortMap() {
	# [UPnP_RemoteHost=<IP>] [...] UPnP_PortMap <Add|Delete>
	local Action="$1" n v dt
	
	UPnP_EnsureURI
	{
		cat <<\EOF
<?xml version="1.0"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
	<SOAP-ENV:Body>
EOF
		echo "<m:${Action}PortMapping xmlns:m=\"urn:schemas-upnp-org:service:WANIPConnection:1\">"
		set |
		 sed 's:^UPnP_::;t;d' |
		 while IFS='=' read n v; do
			dt=
			case "${n}" in
			RemotePort | ExternalPort | InternalPort)
				dt='ui2'
				;;
			Enabled)
				dt='boolean'
				;;
			LeaseDuration)
				dt='ui4'
				;;
			RemoteHost | Protocol | InternalClient | PortMappingDescription)
				dt='string'
				;;
			esac
			[ -n "${dt}" ] &&
			echo "<New${n} xmlns:dt="urn:schemas-microsoft-com:datatypes" dt:dt=\"string\">${v}</New${n}>"
		done
		echo "</m:${Action}PortMapping>"
		cat <<\EOF
	</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
EOF
	} |
	curl \
		--user-agent "Luke-Jr's UPnP Port Forwarding Script (invoked as $0)" \
		--header 'SOAPAction: "urn:schemas-upnp-org:service:WANIPConnection:1#${Action}PortMapping"' \
		--header 'Content-Type: text/xml; charset="utf-8"' \
		--data-binary '@-' \
		"${UPnP_URI}" \
		>/dev/null
}

UPnP_PortFwd() {
	# UPnP_PortFwd <Protocol> <Port> <Description> [DestIP] [DestPort]
	local Protocol="$1" Port="$2" Description="$3" DestIP="$4" DestPort="$5"
	
	[ -z "$DestIP"   ] && DestIP="$(_DetermineMyLANIP)"
	[ -z "$DestPort" ] && DestPort="${Port}"
	
	UPnP_RemoteHost= \
	UPnP_ExternalPort="$Port" \
	UPnP_Protocol="$Protocol" \
	UPnP_PortMap Delete
	
	UPnP_RemoteHost= \
	UPnP_ExternalPort="$Port" \
	UPnP_Protocol="$Protocol" \
	UPnP_InternalPort="${DestPort}" \
	UPnP_InternalClient="${DestIP}" \
	UPnP_Enabled=1 \
	UPnP_PortMappingDescription="$Description" \
	UPnP_LeaseDuration=0 \
	UPnP_PortMap Add
}

UPnP_LAN_Interface="$2"
MyCmd="$3"
[ "$1" == '-i' ] || MyCmd=
shift 3

if [ -z "$MyCmd" ]; then
	exec >&2
	echo "  Usage: $0 -i <Interface> <Command> <Arguments>"
	echo "Example: $0 -i eth0 PortFwd TCP 22 SSH"
	echo ''
	echo 'Commands:'
	echo "	[UPnP_RemoteHost=<IP>] [...] $0 -i <Interface> PortMap <Add|Delete>"
	echo "	$0 -i <Interface> PortFwd <Protocol> <Port> <Description> [DestIP] [DestPort]"
	exit 1
fi

"UPnP_${MyCmd}" "$@"