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package com.btr.proxy.util;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Socket;
import java.util.Arrays;
public class SocksTester {
private static byte[] SOCKS_4_HANDSHAKE = new byte[] {
0x04, // Version
0x01, // establish connection
0x23, (byte)0x82, // Port 9090
0x01, 0x01, 0x01, 0x01, // 1.1.1.1
0x46, 0x72, 0x65, 0x64, 0x00 // Fred\0
};
/**
* Connect to the given host:port and try to talk SOCKS4
* to it, requesting a connection to 1.1.1.1:9090.
* If the server replies using the SOCKS protocol,
* we return true, false otherwise.
* If mustAccept is set, we additionally check that
* the SOCKS proxy actually granted the outgoing connection
* request.
*
* @param host
* @param port
* @return
*/
public static boolean trySocks4(String host, int port, boolean mustAccept) {
Arrays.copyOf(SOCKS_4_HANDSHAKE, SOCKS_4_HANDSHAKE.length);
try (Socket socket = new Socket(Proxy.NO_PROXY)) {
socket.connect(new InetSocketAddress(host, port), 1000);
byte[] buffer = new byte[13];
buffer[0] = 0x04;
buffer[1] = 0x01;
InetSocketAddress google = new InetSocketAddress("www.google.com", 80);
google.getAddress().getAddress();
socket.getOutputStream().write(SOCKS_4_HANDSHAKE);
int num = socket.getInputStream().read(buffer);
// Wrong length or wrong header
if (num < 8 || buffer[0] != 0x00)
return false;
if (mustAccept) {
// Must be accept code
if (buffer[1] != 0x5A)
return false;
} else {
// Must be any valid return code
if (buffer[1] < 0x5A || buffer[1] > 0x5D)
return false;
}
} catch (Exception e) {
return false;
}
return true;
}
}
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