TCPTelnet.java

/*
 * Copyright 2015-2025 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package sockslib.utils;

import sockslib.client.SocksProxy;
import sockslib.client.SocksSocket;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;

/**
 * The class <code>TCPTelnet</code> implements {@link Telnet} based on TCP protocol.
 *
 * @author Youchao Feng
 * @version 1.0
 * @date Oct 15, 2015 12:42 PM
 * @see Telnet
 * @see UDPTelnet
 */
public final class TCPTelnet implements Telnet {

  private TelnetSocketInitializer socketInitializer;

  private SocksProxy proxy;

  public TCPTelnet() {
  }

  public TCPTelnet(SocksProxy proxy) {
    this.proxy = proxy;
  }

  @Override public byte[] request(final byte[] outputBytes, final String host, final int port)
      throws IOException {
    return request(outputBytes, new InetSocketAddress(host, port));
  }

  @Override public byte[] request(final byte[] outputBytes, final SocketAddress address)
      throws IOException {
    InputStream inputStream = null;
    OutputStream outputStream = null;
    ByteArrayOutputStream cache = null;
    Socket socket = null;
    if (proxy != null) {
      socket = new SocksSocket(proxy);
    } else {
      socket = new Socket();
    }
    byte[] response = null;
    IOException exception = null;
    try {
      if (socketInitializer != null) {
        socket = socketInitializer.init(socket);
      }
      socket.connect(address);
      outputStream = new BufferedOutputStream(socket.getOutputStream());
      inputStream = new BufferedInputStream(socket.getInputStream());
      outputStream.write(outputBytes);
      outputStream.flush();
      cache = new ByteArrayOutputStream();
      byte[] buffer = new byte[1024 * 5];
      int length = 0;
      while ((length = inputStream.read(buffer)) > 0) {
        cache.write(buffer, 0, length);
      }
      response = cache.toByteArray();
    } catch (IOException e) {
      exception = e;
    } finally {
      ResourceUtil.close(inputStream);
      ResourceUtil.close(outputStream);
      ResourceUtil.close(socket);
    }
    if (exception != null) {
      throw exception;
    }
    return response;
  }

  public TelnetSocketInitializer getSocketInitializer() {
    return socketInitializer;
  }

  public void setSocketInitializer(final TelnetSocketInitializer socketInitializer) {
    this.socketInitializer = socketInitializer;
  }

  public SocksProxy getProxy() {
    return proxy;
  }

  public void setProxy(SocksProxy proxy) {
    this.proxy = proxy;
  }
}