package com.btr.proxy.search.wpad;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.Proxy;
import java.net.ProxySelector;
import java.net.Socket;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.net.UnknownHostException;
import java.util.List;
import java.util.Properties;
import com.btr.proxy.search.ProxySearchStrategy;
import com.btr.proxy.util.Logger;
import com.btr.proxy.util.Logger.LogLevel;
import com.btr.proxy.util.ProxyUtil;
/*****************************************************************************
* Uses automatic proxy script search (WPAD) to find an PAC file automatically.
* <p>
* Note: at the moment only the DNS name guessing schema is implemented. All
* others are missing.
* </p>
* <p>
* For more information about WPAD: <a
* href="http://en.wikipedia.org/wiki/Web_Proxy_Autodiscovery_Protocol"
* >Web_Proxy_Autodiscovery_Protocol</a>
* </p>
* <p>
* Outdated RFC draft: <a href=
* "http://www.web-cache.com/Writings/Internet-Drafts/draft-ietf-wrec-wpad-01.txt"
* >draft-ietf-wrec-wpad-01.txt</a>
* </p>
*
* @author Bernd Rosstauscher (proxyvole@rosstauscher.de) Copyright 2009
****************************************************************************/
public class WpadProxySearchStrategy implements ProxySearchStrategy {
/*************************************************************************
* Constructor
************************************************************************/
public WpadProxySearchStrategy() {
super();
}
/*************************************************************************
* Loads the proxy settings from a PAC file.
* The location of the PAC file is determined automatically.
*
* @return a configured ProxySelector, null if none is found.
************************************************************************/
public ProxySelector getProxySelector() {
Logger.log(getClass(), LogLevel.TRACE, "Using WPAD to find a proxy");
String pacScriptUrl = detectScriptUrlPerDNS();
if (pacScriptUrl == null) {
return null;
}
Logger.log(getClass(), LogLevel.TRACE, "PAC script url found: {0}", pacScriptUrl);
return ProxyUtil.buildPacSelectorForUrl(pacScriptUrl);
}
/*************************************************************************
* Loads the settings and stores them in a properties map.
*
* @return the settings.
************************************************************************/
public Properties readSettings() {
String pacScriptUrl = detectScriptUrlPerDNS();
if (pacScriptUrl == null) {
return null;
}
Properties result = new Properties();
result.setProperty("url", pacScriptUrl);
return result;
}
/*************************************************************************
* Uses DNS to find the script URL.
* Attention: this detection method is known to have some severe security
* issues.
*
* @return the URL, null if not found.
************************************************************************/
private String detectScriptUrlPerDNS() {
// TODO: Java way of finding all search domains? Seems not trivial
// Windows workaround could be running ipconfig /all and parsing...
Logger.log(getClass(), LogLevel.TRACE, "Searching per DNS guessing.");
String ret;
int index;
ret = tryUrl("http://wpad/wpad.dat");
if (ret != null)
return ret;
String fqdn = null;
try {
fqdn = InetAddress.getLocalHost().getCanonicalHostName();
} catch (UnknownHostException e2) {
// Not successful, try other methods
}
if (fqdn != null && !fqdn.matches("\\d+\\.\\d+\\.\\d+\\.\\d+") && (index = fqdn.indexOf('.')) != -1) {
ret = tryUrl("http://wpad." + fqdn.substring(index + 1) + "/wpad.dat");
if (ret != null)
return ret;
}
BufferedReader br = null;
String[] addresses = null;
try {
FileReader fr = new FileReader("/etc/resolv.conf");
br = new BufferedReader(fr);
String input;
while ((input = br.readLine()) != null) {
if (input.startsWith("search")) {
// the first one is "search" and afterwards addresses are following.
addresses = input.substring(6).split(" ");
break;
}
}
} catch (IOException e1) {
Logger.log(getClass(), LogLevel.DEBUG, "Could not read resolv.conf");
} finally {
try {
br.close();
} catch (Exception e) {
}
}
if (addresses == null) {
addresses = new String[] { "" };
}
for (int i = 0; i < addresses.length; ++i) {
String address = addresses[i].trim().replaceAll("^\\.+", "").replaceAll("\\.+$", "");
if (address.length() < 4)
continue;
do {
ret = tryUrl("http://wpad." + address + "/wpad.dat");
if (ret != null)
return ret;
// don't construct something like wpad.de....
index = address.indexOf('.');
if (index == -1 || index + 7 > address.length())
break;
address = address.substring(index + 1);
if (address.indexOf('.') == -1)
break;
} while (true);
}
return null;
}
private String tryUrl(String url) {
try {
URL lookupURL = new URL(url);
Logger.log(getClass(), LogLevel.DEBUG, "Trying url: {0}", lookupURL);
HttpURLConnection con = (HttpURLConnection) lookupURL.openConnection(Proxy.NO_PROXY);
con.setConnectTimeout(1500);
con.setReadTimeout(2500);
con.setRequestMethod("HEAD");
con.setInstanceFollowRedirects(true);
con.setRequestProperty("accept", "application/x-ns-proxy-autoconfig");
if (con.getResponseCode() == 200) {
String result = lookupURL.toString();
return result;
}
con.disconnect();
} catch (Exception e) {
Logger.log(getClass(), LogLevel.DEBUG, "Not available ({0})", e);
// Not a real error, try next address
}
return null;
}
// Main method for testing.
public static void main(String[] args) throws IOException {
WpadProxySearchStrategy wPSS = new WpadProxySearchStrategy();
// System.setProperty("com.btr.proxy.pac.overrideLocalIP", "10.0.0.1");
try {
ProxySelector pS = wPSS.getProxySelector();
ProxySelector.setDefault(pS);
List<Proxy> proxyList = pS.select(new URI("http://www.google.de"));
if (proxyList.isEmpty()) {
Logger.log(WpadProxySearchStrategy.class, LogLevel.INFO, "ProxyList is empty!");
} else {
Logger.log(WpadProxySearchStrategy.class, LogLevel.INFO, "proxyList contains: {0}",
proxyList.toString());
}
} catch (URISyntaxException e) {
// TODO bjoern 28.10.2014 Auto-generated catch block
e.printStackTrace();
}
URL test = new URL("http://www.google.de");
URLConnection uc = test.openConnection();
BufferedReader br = new BufferedReader(new InputStreamReader(uc.getInputStream()));
String inputLine;
while ((inputLine = br.readLine()) != null) {
System.out.println(inputLine);
}
Socket socket = new Socket("www.google.de", 80);
try {
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
bw.write("GET / HTTP/1.1\r\nHost: www.google.de\r\nConnection: close\r\nAccept-Encoding: *\r\n\r\n");
bw.flush();
br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while ((inputLine = br.readLine()) != null) {
System.out.println(inputLine);
}
} finally {
socket.close();
}
}
}
