ClientServerHello.java :  » Net » Ganymed-SSH-2 » ch » ethz » ssh2 » transport » Java Open Source

package ch.ethz.ssh2.transport;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import ch.ethz.ssh2.Connection;

/**
 * ClientServerHello.
 * 
 * @author Christian Plattner, plattner@inf.ethz.ch
 * @version $Id: ClientServerHello.java,v 1.8 2006/08/02 11:57:12 cplattne Exp $
 */
public class ClientServerHello
{
  String server_line;
  String client_line;

  String server_versioncomment;

  public final static int readLineRN(InputStream is, byte[] buffer) throws IOException
  {
    int pos = 0;
    boolean need10 = false;
    int len = 0;
    while (true)
    {
      int c = is.read();
      if (c == -1)
        throw new IOException("Premature connection close");

      buffer[pos++] = (byte) c;

      if (c == 13)
      {
        need10 = true;
        continue;
      }

      if (c == 10)
        break;

      if (need10 == true)
        throw new IOException("Malformed line sent by the server, the line does not end correctly.");

      len++;
      if (pos >= buffer.length)
        throw new IOException("The server sent a too long line.");
    }

    return len;
  }

  public ClientServerHello(InputStream bi, OutputStream bo) throws IOException
  {
    client_line = "SSH-2.0-" + Connection.identification;

    bo.write((client_line + "\r\n").getBytes());
    bo.flush();

    byte[] serverVersion = new byte[512];

    for (int i = 0; i < 50; i++)
    {
      int len = readLineRN(bi, serverVersion);

      server_line = new String(serverVersion, 0, len);

      if (server_line.startsWith("SSH-"))
        break;
    }

    if (server_line.startsWith("SSH-") == false)
      throw new IOException(
          "Malformed server identification string. There was no line starting with 'SSH-' amongst the first 50 lines.");

    if (server_line.startsWith("SSH-1.99-"))
      server_versioncomment = server_line.substring(9);
    else if (server_line.startsWith("SSH-2.0-"))
      server_versioncomment = server_line.substring(8);
    else
      throw new IOException("Server uses incompatible protocol, it is not SSH-2 compatible.");
  }

  /**
   * @return Returns the client_versioncomment.
   */
  public byte[] getClientString()
  {
    return client_line.getBytes();
  }

  /**
   * @return Returns the server_versioncomment.
   */
  public byte[] getServerString()
  {
    return server_line.getBytes();
  }
}