#!/bin/sh

FRITZBOX="192.168.0.1"

PAYLOAD=\
'<?xml version="1.0" encoding="utf-8" ?>
<s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
  <s:Body>
    <u:GetExternalIPAddress xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1" />
  </s:Body>
</s:Envelope>'

curl -s "http://$FRITZBOX:49000/igdupnp/control/WANIPConn1" \
     -H "Content-Type: text/xml; charset=utf-8" \
     -H "SoapAction:urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIPAddress" \
     -d "$PAYLOAD" | grep -Eo "\<[[:digit:]]{1,3}(\.[[:digit:]]{1,3}){3}\>"