--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ch/ethz/ssh2/Connection.java	Fri Jul 18 11:21:46 2014 -0700
@@ -0,0 +1,1273 @@
+/*
+ * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
+ * Please refer to the LICENSE.txt for licensing details.
+ */
+
+package ch.ethz.ssh2;
+
+import java.io.CharArrayWriter;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.SocketTimeoutException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import ch.ethz.ssh2.auth.AgentProxy;
+import ch.ethz.ssh2.auth.AuthenticationManager;
+import ch.ethz.ssh2.channel.ChannelManager;
+import ch.ethz.ssh2.compression.CompressionFactory;
+import ch.ethz.ssh2.crypto.CryptoWishList;
+import ch.ethz.ssh2.crypto.cipher.BlockCipherFactory;
+import ch.ethz.ssh2.crypto.digest.MAC;
+import ch.ethz.ssh2.packets.PacketIgnore;
+import ch.ethz.ssh2.transport.ClientTransportManager;
+import ch.ethz.ssh2.transport.HTTPProxyClientTransportManager;
+import ch.ethz.ssh2.transport.KexManager;
+import ch.ethz.ssh2.util.TimeoutService;
+import ch.ethz.ssh2.util.TimeoutService.TimeoutToken;
+
+/**
+ * A <code>Connection</code> is used to establish an encrypted TCP/IP
+ * connection to a SSH-2 server.
+ * <p/>
+ * Typically, one
+ * <ol>
+ * <li>creates a {@link #Connection(String) Connection} object.</li>
+ * <li>calls the {@link #connect() connect()} method.</li>
+ * <li>calls some of the authentication methods (e.g., {@link #authenticateWithPublicKey(String, File, String) authenticateWithPublicKey()}).</li>
+ * <li>calls one or several times the {@link #openSession() openSession()} method.</li>
+ * <li>finally, one must close the connection and release resources with the {@link #close() close()} method.</li>
+ * </ol>
+ *
+ * @author Christian Plattner
+ * @version $Id: Connection.java 160 2014-05-01 14:30:26Z dkocher@sudo.ch $
+ */
+
+public class Connection {
+    /**
+     * The identifier presented to the SSH-2 server. This is the same
+     * as the "softwareversion" defined in RFC 4253.
+     * <p/>
+     * <b>NOTE: As per the RFC, the "softwareversion" string MUST consist of printable
+     * US-ASCII characters, with the exception of whitespace characters and the minus sign (-).</b>
+     */
+    private String softwareversion
+            = String.format("Ganymed_%s", Version.getSpecification());
+
+	/* Will be used to generate all random data needed for the current connection.
+     * Note: SecureRandom.nextBytes() is thread safe.
+	 */
+
+    private SecureRandom generator;
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     *
+     * @return The list of supported cipher algorithms by this implementation.
+     */
+    public static synchronized String[] getAvailableCiphers() {
+        return BlockCipherFactory.getDefaultCipherList();
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     *
+     * @return The list of supported MAC algorthims by this implementation.
+     */
+    public static synchronized String[] getAvailableMACs() {
+        return MAC.getMacList();
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     *
+     * @return The list of supported server host key algorthims by this implementation.
+     */
+    public static synchronized String[] getAvailableServerHostKeyAlgorithms() {
+        return KexManager.getDefaultServerHostkeyAlgorithmList();
+    }
+
+    private AuthenticationManager am;
+
+    private boolean authenticated;
+    private ChannelManager cm;
+
+    private CryptoWishList cryptoWishList
+            = new CryptoWishList();
+
+    private DHGexParameters dhgexpara
+            = new DHGexParameters();
+
+    private final String hostname;
+
+    private final int port;
+
+    private ClientTransportManager tm;
+
+    private boolean tcpNoDelay = false;
+
+    private HTTPProxyData proxy;
+
+    private List<ConnectionMonitor> connectionMonitors
+            = new ArrayList<ConnectionMonitor>();
+
+    /**
+     * Prepares a fresh <code>Connection</code> object which can then be used
+     * to establish a connection to the specified SSH-2 server.
+     * <p/>
+     * Same as {@link #Connection(String, int) Connection(hostname, 22)}.
+     *
+     * @param hostname the hostname of the SSH-2 server.
+     */
+    public Connection(String hostname) {
+        this(hostname, 22);
+    }
+
+    /**
+     * Prepares a fresh <code>Connection</code> object which can then be used
+     * to establish a connection to the specified SSH-2 server.
+     *
+     * @param hostname the host where we later want to connect to.
+     * @param port     port on the server, normally 22.
+     */
+    public Connection(String hostname, int port) {
+        this.hostname = hostname;
+        this.port = port;
+    }
+
+    /**
+     * Prepares a fresh <code>Connection</code> object which can then be used
+     * to establish a connection to the specified SSH-2 server.
+     *
+     * @param hostname        the host where we later want to connect to.
+     * @param port            port on the server, normally 22.
+     * @param softwareversion Allows you to set a custom "softwareversion" string as defined in RFC 4253.
+     *                        <b>NOTE: As per the RFC, the "softwareversion" string MUST consist of printable
+     *                        US-ASCII characters, with the exception of whitespace characters and the minus sign (-).</b>
+     */
+    public Connection(String hostname, int port, String softwareversion) {
+        this.hostname = hostname;
+        this.port = port;
+        this.softwareversion = softwareversion;
+    }
+
+    public Connection(String hostname, int port, final HTTPProxyData proxy) {
+        this.hostname = hostname;
+        this.port = port;
+        this.proxy = proxy;
+    }
+
+    public Connection(String hostname, int port, String softwareversion, final HTTPProxyData proxy) {
+        this.hostname = hostname;
+        this.port = port;
+        this.softwareversion = softwareversion;
+        this.proxy = proxy;
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself. This method
+     * is based on DSA (it uses DSA to sign a challenge sent by the server).
+     * <p/>
+     * If the authentication phase is complete, <code>true</code> will be
+     * returned. If the server does not accept the request (or if further
+     * authentication steps are needed), <code>false</code> is returned and
+     * one can retry either by using this or any other authentication method
+     * (use the <code>getRemainingAuthMethods</code> method to get a list of
+     * the remaining possible methods).
+     *
+     * @param user     A <code>String</code> holding the username.
+     * @param pem      A <code>String</code> containing the DSA private key of the
+     *                 user in OpenSSH key format (PEM, you can't miss the
+     *                 "-----BEGIN DSA PRIVATE KEY-----" tag). The string may contain
+     *                 linefeeds.
+     * @param password If the PEM string is 3DES encrypted ("DES-EDE3-CBC"), then you
+     *                 must specify the password. Otherwise, this argument will be
+     *                 ignored and can be set to <code>null</code>.
+     * @return whether the connection is now authenticated.
+     * @throws IOException
+     * @deprecated You should use one of the {@link #authenticateWithPublicKey(String, File, String) authenticateWithPublicKey()}
+     * methods, this method is just a wrapper for it and will
+     * disappear in future builds.
+     */
+    public synchronized boolean authenticateWithDSA(String user, String pem, String password) throws IOException {
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+        if(pem == null) {
+            throw new IllegalArgumentException("pem argument is null");
+        }
+
+        authenticated = am.authenticatePublicKey(user, pem.toCharArray(), password, getOrCreateSecureRND());
+
+        return authenticated;
+    }
+
+    /**
+     * A wrapper that calls {@link #authenticateWithKeyboardInteractive(String, String[], InteractiveCallback)
+     * authenticateWithKeyboardInteractivewith} a <code>null</code> submethod list.
+     *
+     * @param user A <code>String</code> holding the username.
+     * @param cb   An <code>InteractiveCallback</code> which will be used to
+     *             determine the responses to the questions asked by the server.
+     * @return whether the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithKeyboardInteractive(String user, InteractiveCallback cb)
+            throws IOException {
+        return authenticateWithKeyboardInteractive(user, null, cb);
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself. This method
+     * is based on "keyboard-interactive", specified in
+     * draft-ietf-secsh-auth-kbdinteract-XX. Basically, you have to define a
+     * callback object which will be feeded with challenges generated by the
+     * server. Answers are then sent back to the server. It is possible that the
+     * callback will be called several times during the invocation of this
+     * method (e.g., if the server replies to the callback's answer(s) with
+     * another challenge...)
+     * <p/>
+     * If the authentication phase is complete, <code>true</code> will be
+     * returned. If the server does not accept the request (or if further
+     * authentication steps are needed), <code>false</code> is returned and
+     * one can retry either by using this or any other authentication method
+     * (use the <code>getRemainingAuthMethods</code> method to get a list of
+     * the remaining possible methods).
+     * <p/>
+     * Note: some SSH servers advertise "keyboard-interactive", however, any
+     * interactive request will be denied (without having sent any challenge to
+     * the client).
+     *
+     * @param user       A <code>String</code> holding the username.
+     * @param submethods An array of submethod names, see
+     *                   draft-ietf-secsh-auth-kbdinteract-XX. May be <code>null</code>
+     *                   to indicate an empty list.
+     * @param cb         An <code>InteractiveCallback</code> which will be used to
+     *                   determine the responses to the questions asked by the server.
+     * @return whether the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithKeyboardInteractive(String user, String[] submethods,
+                                                                    InteractiveCallback cb) throws IOException {
+        if(cb == null) {
+            throw new IllegalArgumentException("Callback may not ne NULL!");
+        }
+
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+        authenticated = am.authenticateInteractive(user, submethods, cb);
+
+        return authenticated;
+    }
+
+    public synchronized boolean authenticateWithAgent(String user, AgentProxy proxy) throws IOException {
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+        authenticated = am.authenticatePublicKey(user, proxy);
+
+        return authenticated;
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself. This method
+     * sends username and password to the server.
+     * <p/>
+     * If the authentication phase is complete, <code>true</code> will be
+     * returned. If the server does not accept the request (or if further
+     * authentication steps are needed), <code>false</code> is returned and
+     * one can retry either by using this or any other authentication method
+     * (use the <code>getRemainingAuthMethods</code> method to get a list of
+     * the remaining possible methods).
+     * <p/>
+     * Note: if this method fails, then please double-check that it is actually
+     * offered by the server (use {@link #getRemainingAuthMethods(String) getRemainingAuthMethods()}.
+     * <p/>
+     * Often, password authentication is disabled, but users are not aware of it.
+     * Many servers only offer "publickey" and "keyboard-interactive". However,
+     * even though "keyboard-interactive" *feels* like password authentication
+     * (e.g., when using the putty or openssh clients) it is *not* the same mechanism.
+     *
+     * @param user
+     * @param password
+     * @return if the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithPassword(String user, String password) throws IOException {
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+        if(password == null) {
+            throw new IllegalArgumentException("password argument is null");
+        }
+
+        authenticated = am.authenticatePassword(user, password);
+
+        return authenticated;
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself.
+     * This method can be used to explicitly use the special "none"
+     * authentication method (where only a username has to be specified).
+     * <p/>
+     * Note 1: The "none" method may always be tried by clients, however as by
+     * the specs, the server will not explicitly announce it. In other words,
+     * the "none" token will never show up in the list returned by
+     * {@link #getRemainingAuthMethods(String)}.
+     * <p/>
+     * Note 2: no matter which one of the authenticateWithXXX() methods
+     * you call, the library will always issue exactly one initial "none"
+     * authentication request to retrieve the initially allowed list of
+     * authentication methods by the server. Please read RFC 4252 for the
+     * details.
+     * <p/>
+     * If the authentication phase is complete, <code>true</code> will be
+     * returned. If further authentication steps are needed, <code>false</code>
+     * is returned and one can retry by any other authentication method
+     * (use the <code>getRemainingAuthMethods</code> method to get a list of
+     * the remaining possible methods).
+     *
+     * @param user
+     * @return if the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithNone(String user) throws IOException {
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+		/* Trigger the sending of the PacketUserauthRequestNone packet */
+        /* (if not already done)                                       */
+
+        authenticated = am.authenticateNone(user);
+
+        return authenticated;
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself.
+     * The authentication method "publickey" works by signing a challenge
+     * sent by the server. The signature is either DSA or RSA based - it
+     * just depends on the type of private key you specify, either a DSA
+     * or RSA private key in PEM format. And yes, this is may seem to be a
+     * little confusing, the method is called "publickey" in the SSH-2 protocol
+     * specification, however since we need to generate a signature, you
+     * actually have to supply a private key =).
+     * <p/>
+     * The private key contained in the PEM file may also be encrypted ("Proc-Type: 4,ENCRYPTED").
+     * The library supports DES-CBC and DES-EDE3-CBC encryption, as well
+     * as the more exotic PEM encrpytions AES-128-CBC, AES-192-CBC and AES-256-CBC.
+     * <p/>
+     * If the authentication phase is complete, <code>true</code> will be
+     * returned. If the server does not accept the request (or if further
+     * authentication steps are needed), <code>false</code> is returned and
+     * one can retry either by using this or any other authentication method
+     * (use the <code>getRemainingAuthMethods</code> method to get a list of
+     * the remaining possible methods).
+     * <p/>
+     * NOTE PUTTY USERS: Event though your key file may start with "-----BEGIN..."
+     * it is not in the expected format. You have to convert it to the OpenSSH
+     * key format by using the "puttygen" tool (can be downloaded from the Putty
+     * website). Simply load your key and then use the "Conversions/Export OpenSSH key"
+     * functionality to get a proper PEM file.
+     *
+     * @param user          A <code>String</code> holding the username.
+     * @param pemPrivateKey A <code>char[]</code> containing a DSA or RSA private key of the
+     *                      user in OpenSSH key format (PEM, you can't miss the
+     *                      "-----BEGIN DSA PRIVATE KEY-----" or "-----BEGIN RSA PRIVATE KEY-----"
+     *                      tag). The char array may contain linebreaks/linefeeds.
+     * @param password      If the PEM structure is encrypted ("Proc-Type: 4,ENCRYPTED") then
+     *                      you must specify a password. Otherwise, this argument will be ignored
+     *                      and can be set to <code>null</code>.
+     * @return whether the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithPublicKey(String user, char[] pemPrivateKey, String password)
+            throws IOException {
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        if(user == null) {
+            throw new IllegalArgumentException("user argument is null");
+        }
+
+        if(pemPrivateKey == null) {
+            throw new IllegalArgumentException("pemPrivateKey argument is null");
+        }
+
+        authenticated = am.authenticatePublicKey(user, pemPrivateKey, password, getOrCreateSecureRND());
+
+        return authenticated;
+    }
+
+    /**
+     * A convenience wrapper function which reads in a private key (PEM format, either DSA or RSA)
+     * and then calls <code>authenticateWithPublicKey(String, char[], String)</code>.
+     * <p/>
+     * NOTE PUTTY USERS: Event though your key file may start with "-----BEGIN..."
+     * it is not in the expected format. You have to convert it to the OpenSSH
+     * key format by using the "puttygen" tool (can be downloaded from the Putty
+     * website). Simply load your key and then use the "Conversions/Export OpenSSH key"
+     * functionality to get a proper PEM file.
+     *
+     * @param user     A <code>String</code> holding the username.
+     * @param pemFile  A <code>File</code> object pointing to a file containing a DSA or RSA
+     *                 private key of the user in OpenSSH key format (PEM, you can't miss the
+     *                 "-----BEGIN DSA PRIVATE KEY-----" or "-----BEGIN RSA PRIVATE KEY-----"
+     *                 tag).
+     * @param password If the PEM file is encrypted then you must specify the password.
+     *                 Otherwise, this argument will be ignored and can be set to <code>null</code>.
+     * @return whether the connection is now authenticated.
+     * @throws IOException
+     */
+    public synchronized boolean authenticateWithPublicKey(String user, File pemFile, String password)
+            throws IOException {
+        if(pemFile == null) {
+            throw new IllegalArgumentException("pemFile argument is null");
+        }
+
+        char[] buff = new char[256];
+
+        CharArrayWriter cw = new CharArrayWriter();
+
+        FileReader fr = new FileReader(pemFile);
+
+        while(true) {
+            int len = fr.read(buff);
+            if(len < 0) {
+                break;
+            }
+            cw.write(buff, 0, len);
+        }
+
+        fr.close();
+
+        return authenticateWithPublicKey(user, cw.toCharArray(), password);
+    }
+
+    /**
+     * Add a {@link ConnectionMonitor} to this connection. Can be invoked at any time,
+     * but it is best to add connection monitors before invoking
+     * <code>connect()</code> to avoid glitches (e.g., you add a connection monitor after
+     * a successful connect(), but the connection has died in the mean time. Then,
+     * your connection monitor won't be notified.)
+     * <p/>
+     * You can add as many monitors as you like. If a monitor has already been added, then
+     * this method does nothing.
+     *
+     * @param cmon An object implementing the {@link ConnectionMonitor} interface.
+     * @see ConnectionMonitor
+     */
+    public synchronized void addConnectionMonitor(ConnectionMonitor cmon) {
+        if(!connectionMonitors.contains(cmon)) {
+            connectionMonitors.add(cmon);
+            if(tm != null) {
+                tm.setConnectionMonitors(connectionMonitors);
+            }
+        }
+    }
+
+    /**
+     * Remove a {@link ConnectionMonitor} from this connection.
+     *
+     * @param cmon
+     * @return whether the monitor could be removed
+     */
+    public synchronized boolean removeConnectionMonitor(ConnectionMonitor cmon) {
+        boolean existed = connectionMonitors.remove(cmon);
+        if(tm != null) {
+            tm.setConnectionMonitors(connectionMonitors);
+        }
+        return existed;
+    }
+
+    /**
+     * Close the connection to the SSH-2 server. All assigned sessions will be
+     * closed, too. Can be called at any time. Don't forget to call this once
+     * you don't need a connection anymore - otherwise the receiver thread may
+     * run forever.
+     */
+    public synchronized void close() {
+        if(cm != null) {
+            cm.closeAllChannels();
+        }
+        if(tm != null) {
+            tm.close();
+            tm = null;
+        }
+        am = null;
+        cm = null;
+        authenticated = false;
+    }
+
+    public synchronized void close(IOException t) {
+        if(cm != null) {
+            cm.closeAllChannels();
+        }
+        if(tm != null) {
+            tm.close(t);
+            tm = null;
+        }
+        am = null;
+        cm = null;
+        authenticated = false;
+    }
+
+    /**
+     * Same as {@link #connect(ServerHostKeyVerifier, int, int) connect(null, 0, 0)}.
+     *
+     * @return see comments for the {@link #connect(ServerHostKeyVerifier, int, int) connect(ServerHostKeyVerifier, int, int)} method.
+     * @throws IOException
+     */
+    public synchronized ConnectionInfo connect() throws IOException {
+        return connect(null, 0, 0);
+    }
+
+    /**
+     * Same as {@link #connect(ServerHostKeyVerifier, int, int) connect(verifier, 0, 0)}.
+     *
+     * @return see comments for the {@link #connect(ServerHostKeyVerifier, int, int) connect(ServerHostKeyVerifier, int, int)} method.
+     * @throws IOException
+     */
+    public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier) throws IOException {
+        return connect(verifier, 0, 0);
+    }
+
+    /**
+     * Connect to the SSH-2 server and, as soon as the server has presented its
+     * host key, use the {@link ServerHostKeyVerifier#verifyServerHostKey(String,
+     * int, String, byte[]) ServerHostKeyVerifier.verifyServerHostKey()}
+     * method of the <code>verifier</code> to ask for permission to proceed.
+     * If <code>verifier</code> is <code>null</code>, then any host key will be
+     * accepted - this is NOT recommended, since it makes man-in-the-middle attackes
+     * VERY easy (somebody could put a proxy SSH server between you and the real server).
+     * <p/>
+     * Note: The verifier will be called before doing any crypto calculations
+     * (i.e., diffie-hellman). Therefore, if you don't like the presented host key then
+     * no CPU cycles are wasted (and the evil server has less information about us).
+     * <p/>
+     * However, it is still possible that the server presented a fake host key: the server
+     * cheated (typically a sign for a man-in-the-middle attack) and is not able to generate
+     * a signature that matches its host key. Don't worry, the library will detect such
+     * a scenario later when checking the signature (the signature cannot be checked before
+     * having completed the diffie-hellman exchange).
+     * <p/>
+     * Note 2: The  {@link ServerHostKeyVerifier#verifyServerHostKey(String,
+     * int, String, byte[]) ServerHostKeyVerifier.verifyServerHostKey()} method
+     * will *NOT* be called from the current thread, the call is being made from a
+     * background thread (there is a background dispatcher thread for every
+     * established connection).
+     * <p/>
+     * Note 3: This method will block as long as the key exchange of the underlying connection
+     * has not been completed (and you have not specified any timeouts).
+     * <p/>
+     * Note 4: If you want to re-use a connection object that was successfully connected,
+     * then you must call the {@link #close()} method before invoking <code>connect()</code> again.
+     *
+     * @param verifier       An object that implements the
+     *                       {@link ServerHostKeyVerifier} interface. Pass <code>null</code>
+     *                       to accept any server host key - NOT recommended.
+     * @param connectTimeout Connect the underlying TCP socket to the server with the given timeout
+     *                       value (non-negative, in milliseconds). Zero means no timeout.
+     * @param kexTimeout     Timeout for complete connection establishment (non-negative,
+     *                       in milliseconds). Zero means no timeout. The timeout counts from the
+     *                       moment you invoke the connect() method and is cancelled as soon as the
+     *                       first key-exchange round has finished. It is possible that
+     *                       the timeout event will be fired during the invocation of the
+     *                       <code>verifier</code> callback, but it will only have an effect after
+     *                       the <code>verifier</code> returns.
+     * @return A {@link ConnectionInfo} object containing the details of
+     * the established connection.
+     * @throws IOException If any problem occurs, e.g., the server's host key is not
+     *                     accepted by the <code>verifier</code> or there is problem during
+     *                     the initial crypto setup (e.g., the signature sent by the server is wrong).
+     *                     <p/>
+     *                     In case of a timeout (either connectTimeout or kexTimeout)
+     *                     a SocketTimeoutException is thrown.
+     *                     <p/>
+     *                     An exception may also be thrown if the connection was already successfully
+     *                     connected (no matter if the connection broke in the mean time) and you invoke
+     *                     <code>connect()</code> again without having called {@link #close()} first.
+     *                     <p/>
+     *                     If a HTTP proxy is being used and the proxy refuses the connection,
+     *                     then a {@link HTTPProxyException} may be thrown, which
+     *                     contains the details returned by the proxy. If the proxy is buggy and does
+     *                     not return a proper HTTP response, then a normal IOException is thrown instead.
+     */
+    public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier, int connectTimeout, int kexTimeout)
+            throws IOException {
+        final class TimeoutState {
+            boolean isCancelled = false;
+            boolean timeoutSocketClosed = false;
+        }
+
+        if(tm != null) {
+            throw new IllegalStateException(String.format("Connection to %s is already in connected state", hostname));
+        }
+
+        if(connectTimeout < 0) {
+            throw new IllegalArgumentException("connectTimeout must be non-negative!");
+        }
+
+        if(kexTimeout < 0) {
+            throw new IllegalArgumentException("kexTimeout must be non-negative!");
+        }
+
+        final TimeoutState state = new TimeoutState();
+
+        if(null == proxy) {
+            tm = new ClientTransportManager(new Socket());
+        }
+        else {
+            tm = new HTTPProxyClientTransportManager(new Socket(), proxy);
+        }
+        tm.setSoTimeout(connectTimeout);
+        tm.setTcpNoDelay(tcpNoDelay);
+        tm.setConnectionMonitors(connectionMonitors);
+
+        try {
+            TimeoutToken token = null;
+
+            if(kexTimeout > 0) {
+                final Runnable timeoutHandler = new Runnable() {
+					@Override
+                    public void run() {
+                        synchronized(state) {
+                            if(state.isCancelled) {
+                                return;
+                            }
+                            state.timeoutSocketClosed = true;
+                            tm.close(new SocketTimeoutException("The connect timeout expired"));
+                        }
+                    }
+                };
+
+                long timeoutHorizont = System.currentTimeMillis() + kexTimeout;
+
+                token = TimeoutService.addTimeoutHandler(timeoutHorizont, timeoutHandler);
+            }
+
+            tm.connect(hostname, port, softwareversion, cryptoWishList, verifier, dhgexpara, connectTimeout,
+                    getOrCreateSecureRND());
+
+			/* Wait until first KEX has finished */
+
+            ConnectionInfo ci = tm.getConnectionInfo(1);
+
+			/* Now try to cancel the timeout, if needed */
+
+            if(token != null) {
+                TimeoutService.cancelTimeoutHandler(token);
+
+				/* Were we too late? */
+
+                synchronized(state) {
+                    if(state.timeoutSocketClosed) {
+                        throw new IOException("This exception will be replaced by the one below =)");
+                    }
+                    /* Just in case the "cancelTimeoutHandler" invocation came just a little bit
+                     * too late but the handler did not enter the semaphore yet - we can
+					 * still stop it.
+					 */
+                    state.isCancelled = true;
+                }
+            }
+
+            return ci;
+        }
+        catch(SocketTimeoutException e) {
+            throw e;
+        }
+        catch(HTTPProxyException e) {
+            throw e;
+        }
+        catch(IOException e) {
+            // This will also invoke any registered connection monitors
+            close(e);
+
+            synchronized(state) {
+                /* Show a clean exception, not something like "the socket is closed!?!" */
+                if(state.timeoutSocketClosed) {
+                    throw new SocketTimeoutException(String.format("The kexTimeout (%d ms) expired.", kexTimeout));
+                }
+            }
+            throw e;
+        }
+    }
+
+    /**
+     * Creates a new {@link LocalPortForwarder}.
+     * A <code>LocalPortForwarder</code> forwards TCP/IP connections that arrive at a local
+     * port via the secure tunnel to another host (which may or may not be
+     * identical to the remote SSH-2 server).
+     * <p/>
+     * This method must only be called after one has passed successfully the authentication step.
+     * There is no limit on the number of concurrent forwardings.
+     *
+     * @param local_port      the local port the LocalPortForwarder shall bind to.
+     * @param host_to_connect target address (IP or hostname)
+     * @param port_to_connect target port
+     * @return A {@link LocalPortForwarder} object.
+     * @throws IOException
+     */
+    public synchronized LocalPortForwarder createLocalPortForwarder(int local_port, String host_to_connect,
+                                                                    int port_to_connect) throws IOException {
+        this.checkConnection();
+
+        return new LocalPortForwarder(cm, local_port, host_to_connect, port_to_connect);
+    }
+
+    /**
+     * Creates a new {@link LocalPortForwarder}.
+     * A <code>LocalPortForwarder</code> forwards TCP/IP connections that arrive at a local
+     * port via the secure tunnel to another host (which may or may not be
+     * identical to the remote SSH-2 server).
+     * <p/>
+     * This method must only be called after one has passed successfully the authentication step.
+     * There is no limit on the number of concurrent forwardings.
+     *
+     * @param addr            specifies the InetSocketAddress where the local socket shall be bound to.
+     * @param host_to_connect target address (IP or hostname)
+     * @param port_to_connect target port
+     * @return A {@link LocalPortForwarder} object.
+     * @throws IOException
+     */
+    public synchronized LocalPortForwarder createLocalPortForwarder(InetSocketAddress addr, String host_to_connect,
+                                                                    int port_to_connect) throws IOException {
+        this.checkConnection();
+
+        return new LocalPortForwarder(cm, addr, host_to_connect, port_to_connect);
+    }
+
+    /**
+     * Creates a new {@link LocalStreamForwarder}.
+     * A <code>LocalStreamForwarder</code> manages an Input/Outputstream pair
+     * that is being forwarded via the secure tunnel into a TCP/IP connection to another host
+     * (which may or may not be identical to the remote SSH-2 server).
+     *
+     * @param host_to_connect
+     * @param port_to_connect
+     * @return A {@link LocalStreamForwarder} object.
+     * @throws IOException
+     */
+    public synchronized LocalStreamForwarder createLocalStreamForwarder(String host_to_connect, int port_to_connect)
+            throws IOException {
+        this.checkConnection();
+
+        return new LocalStreamForwarder(cm, host_to_connect, port_to_connect);
+    }
+
+    /**
+     * Create a very basic {@link SCPClient} that can be used to copy
+     * files from/to the SSH-2 server.
+     * <p/>
+     * Works only after one has passed successfully the authentication step.
+     * There is no limit on the number of concurrent SCP clients.
+     * <p/>
+     * Note: This factory method will probably disappear in the future.
+     *
+     * @return A {@link SCPClient} object.
+     * @throws IOException
+     */
+    public synchronized SCPClient createSCPClient() throws IOException {
+        this.checkConnection();
+
+        return new SCPClient(this);
+    }
+
+    /**
+     * Force an asynchronous key re-exchange (the call does not block). The
+     * latest values set for MAC, Cipher and DH group exchange parameters will
+     * be used. If a key exchange is currently in progress, then this method has
+     * the only effect that the so far specified parameters will be used for the
+     * next (server driven) key exchange.
+     * <p/>
+     * Note: This implementation will never start a key exchange (other than the initial one)
+     * unless you or the SSH-2 server ask for it.
+     *
+     * @throws IOException In case of any failure behind the scenes.
+     */
+    public synchronized void forceKeyExchange() throws IOException {
+        this.checkConnection();
+
+        tm.forceKeyExchange(cryptoWishList, dhgexpara, null, null);
+    }
+
+    /**
+     * Returns the hostname that was passed to the constructor.
+     *
+     * @return the hostname
+     */
+    public synchronized String getHostname() {
+        return hostname;
+    }
+
+    /**
+     * Returns the port that was passed to the constructor.
+     *
+     * @return the TCP port
+     */
+    public synchronized int getPort() {
+        return port;
+    }
+
+    /**
+     * Returns a {@link ConnectionInfo} object containing the details of
+     * the connection. Can be called as soon as the connection has been
+     * established (successfully connected).
+     *
+     * @return A {@link ConnectionInfo} object.
+     * @throws IOException In case of any failure behind the scenes.
+     */
+    public synchronized ConnectionInfo getConnectionInfo() throws IOException {
+        this.checkConnection();
+
+        return tm.getConnectionInfo(1);
+    }
+
+    /**
+     * After a successful connect, one has to authenticate oneself. This method
+     * can be used to tell which authentication methods are supported by the
+     * server at a certain stage of the authentication process (for the given
+     * username).
+     * <p/>
+     * Note 1: the username will only be used if no authentication step was done
+     * so far (it will be used to ask the server for a list of possible
+     * authentication methods by sending the initial "none" request). Otherwise,
+     * this method ignores the user name and returns a cached method list
+     * (which is based on the information contained in the last negative server response).
+     * <p/>
+     * Note 2: the server may return method names that are not supported by this
+     * implementation.
+     * <p/>
+     * After a successful authentication, this method must not be called
+     * anymore.
+     *
+     * @param user A <code>String</code> holding the username.
+     * @return a (possibly emtpy) array holding authentication method names.
+     * @throws IOException
+     */
+    public synchronized String[] getRemainingAuthMethods(String user) throws IOException {
+        if(user == null) {
+            throw new IllegalArgumentException("user argument may not be NULL!");
+        }
+
+        if(tm == null) {
+            throw new IllegalStateException("Connection is not established!");
+        }
+
+        if(authenticated) {
+            throw new IllegalStateException("Connection is already authenticated!");
+        }
+
+        if(am == null) {
+            am = new AuthenticationManager(tm);
+        }
+
+        if(cm == null) {
+            cm = new ChannelManager(tm);
+        }
+
+        final Set<String> remainingMethods = am.getRemainingMethods(user);
+        return remainingMethods.toArray(new String[remainingMethods.size()]);
+    }
+
+    /**
+     * Determines if the authentication phase is complete. Can be called at any
+     * time.
+     *
+     * @return <code>true</code> if no further authentication steps are
+     * needed.
+     */
+    public synchronized boolean isAuthenticationComplete() {
+        return authenticated;
+    }
+
+    /**
+     * Returns true if there was at least one failed authentication request and
+     * the last failed authentication request was marked with "partial success"
+     * by the server. This is only needed in the rare case of SSH-2 server setups
+     * that cannot be satisfied with a single successful authentication request
+     * (i.e., multiple authentication steps are needed.)
+     * <p/>
+     * If you are interested in the details, then have a look at RFC4252.
+     *
+     * @return if the there was a failed authentication step and the last one
+     * was marked as a "partial success".
+     */
+    public synchronized boolean isAuthenticationPartialSuccess() {
+        if(am == null) {
+            return false;
+        }
+        return am.getPartialSuccess();
+    }
+
+    /**
+     * Checks if a specified authentication method is available. This method is
+     * actually just a wrapper for {@link #getRemainingAuthMethods(String)
+     * getRemainingAuthMethods()}.
+     *
+     * @param user   A <code>String</code> holding the username.
+     * @param method An authentication method name (e.g., "publickey", "password",
+     *               "keyboard-interactive") as specified by the SSH-2 standard.
+     * @return if the specified authentication method is currently available.
+     * @throws IOException
+     */
+    public synchronized boolean isAuthMethodAvailable(String user, String method) throws IOException {
+        String methods[] = getRemainingAuthMethods(user);
+        for(final String m : methods) {
+            if(m.compareTo(method) == 0) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private SecureRandom getOrCreateSecureRND() {
+        if(generator == null) {
+            generator = new SecureRandom();
+        }
+        return generator;
+    }
+
+    /**
+     * Open a new {@link Session} on this connection. Works only after one has passed
+     * successfully the authentication step. There is no limit on the number of
+     * concurrent sessions.
+     *
+     * @return A {@link Session} object.
+     * @throws IOException
+     */
+    public synchronized Session openSession() throws IOException {
+        this.checkConnection();
+
+        return new Session(cm, getOrCreateSecureRND());
+    }
+
+    /**
+     * Send an SSH_MSG_IGNORE packet. This method will generate a random data attribute
+     * (length between 0 (invlusive) and 16 (exclusive) bytes, contents are random bytes).
+     * <p/>
+     * This method must only be called once the connection is established.
+     *
+     * @throws IOException
+     */
+    public synchronized void sendIgnorePacket() throws IOException {
+        SecureRandom rnd = getOrCreateSecureRND();
+
+        byte[] data = new byte[rnd.nextInt(16)];
+        rnd.nextBytes(data);
+
+        sendIgnorePacket(data);
+    }
+
+    /**
+     * Send an SSH_MSG_IGNORE packet with the given data attribute.
+     * <p/>
+     * This method must only be called once the connection is established.
+     *
+     * @throws IOException
+     */
+    public synchronized void sendIgnorePacket(byte[] data) throws IOException {
+        this.checkConnection();
+
+        PacketIgnore pi = new PacketIgnore(data);
+
+        tm.sendMessage(pi.getPayload());
+    }
+
+    /**
+     * Controls whether compression is used on the link or not.
+     */
+    public synchronized void setCompression(String[] algorithms) {
+        CompressionFactory.checkCompressorList(algorithms);
+        cryptoWishList.c2s_comp_algos = algorithms;
+    }
+
+    public synchronized void enableCompression() {
+        cryptoWishList.c2s_comp_algos = CompressionFactory.getDefaultCompressorList();
+        cryptoWishList.s2c_comp_algos = CompressionFactory.getDefaultCompressorList();
+    }
+
+    public synchronized void disableCompression() {
+        cryptoWishList.c2s_comp_algos = new String[]{"none"};
+        cryptoWishList.s2c_comp_algos = new String[]{"none"};
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     */
+    public synchronized void setClient2ServerCiphers(final String[] ciphers) {
+        if((ciphers == null) || (ciphers.length == 0)) {
+            throw new IllegalArgumentException();
+        }
+        BlockCipherFactory.checkCipherList(ciphers);
+        cryptoWishList.c2s_enc_algos = ciphers;
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     */
+    public synchronized void setClient2ServerMACs(final String[] macs) {
+        MAC.checkMacList(macs);
+        cryptoWishList.c2s_mac_algos = macs;
+    }
+
+    /**
+     * Sets the parameters for the diffie-hellman group exchange. Unless you
+     * know what you are doing, you will never need this. Default values are
+     * defined in the {@link DHGexParameters} class.
+     *
+     * @param dgp {@link DHGexParameters}, non null.
+     */
+    public synchronized void setDHGexParameters(DHGexParameters dgp) {
+        if(dgp == null) {
+            throw new IllegalArgumentException();
+        }
+
+        dhgexpara = dgp;
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     */
+    public synchronized void setServer2ClientCiphers(final String[] ciphers) {
+        BlockCipherFactory.checkCipherList(ciphers);
+        cryptoWishList.s2c_enc_algos = ciphers;
+    }
+
+    /**
+     * Unless you know what you are doing, you will never need this.
+     */
+    public synchronized void setServer2ClientMACs(final String[] macs) {
+        MAC.checkMacList(macs);
+        cryptoWishList.s2c_mac_algos = macs;
+    }
+
+    /**
+     * Define the set of allowed server host key algorithms to be used for
+     * the following key exchange operations.
+     * <p/>
+     * Unless you know what you are doing, you will never need this.
+     *
+     * @param algos An array of allowed server host key algorithms.
+     *              SSH-2 defines <code>ssh-dss</code> and <code>ssh-rsa</code>.
+     *              The entries of the array must be ordered after preference, i.e.,
+     *              the entry at index 0 is the most preferred one. You must specify
+     *              at least one entry.
+     */
+    public synchronized void setServerHostKeyAlgorithms(final String[] algos) {
+        KexManager.checkServerHostkeyAlgorithmsList(algos);
+        cryptoWishList.serverHostKeyAlgorithms = algos;
+    }
+
+    /**
+     * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm) on the underlying socket.
+     * <p/>
+     * Can be called at any time. If the connection has not yet been established
+     * then the passed value will be stored and set after the socket has been set up.
+     * The default value that will be used is <code>false</code>.
+     *
+     * @param enable the argument passed to the <code>Socket.setTCPNoDelay()</code> method.
+     * @throws IOException
+     */
+    public synchronized void setTCPNoDelay(boolean enable) throws IOException {
+        tcpNoDelay = enable;
+        if(tm != null) {
+            tm.setTcpNoDelay(enable);
+        }
+    }
+
+    /**
+     * Request a remote port forwarding.
+     * If successful, then forwarded connections will be redirected to the given target address.
+     * You can cancle a requested remote port forwarding by calling
+     * {@link #cancelRemotePortForwarding(int) cancelRemotePortForwarding()}.
+     * <p/>
+     * A call of this method will block until the peer either agreed or disagreed to your request-
+     * <p/>
+     * Note 1: this method typically fails if you
+     * <ul>
+     * <li>pass a port number for which the used remote user has not enough permissions (i.e., port
+     * &lt; 1024)</li>
+     * <li>or pass a port number that is already in use on the remote server</li>
+     * <li>or if remote port forwarding is disabled on the server.</li>
+     * </ul>
+     * <p/>
+     * Note 2: (from the openssh man page): By default, the listening socket on the server will be
+     * bound to the loopback interface only. This may be overriden by specifying a bind address.
+     * Specifying a remote bind address will only succeed if the server's <b>GatewayPorts</b> option
+     * is enabled (see sshd_config(5)).
+     *
+     * @param bindAddress   address to bind to on the server:
+     *                      <ul>
+     *                      <li>"" means that connections are to be accepted on all protocol families
+     *                      supported by the SSH implementation</li>
+     *                      <li>"0.0.0.0" means to listen on all IPv4 addresses</li>
+     *                      <li>"::" means to listen on all IPv6 addresses</li>
+     *                      <li>"localhost" means to listen on all protocol families supported by the SSH
+     *                      implementation on loopback addresses only, [RFC3330] and RFC3513]</li>
+     *                      <li>"127.0.0.1" and "::1" indicate listening on the loopback interfaces for
+     *                      IPv4 and IPv6 respectively</li>
+     *                      </ul>
+     * @param bindPort      port number to bind on the server (must be &gt; 0)
+     * @param targetAddress the target address (IP or hostname)
+     * @param targetPort    the target port
+     * @throws IOException
+     */
+    public synchronized void requestRemotePortForwarding(String bindAddress, int bindPort, String targetAddress,
+                                                         int targetPort) throws IOException {
+        this.checkConnection();
+
+        if((bindAddress == null) || (targetAddress == null) || (bindPort <= 0) || (targetPort <= 0)) {
+            throw new IllegalArgumentException();
+        }
+
+        cm.requestGlobalForward(bindAddress, bindPort, targetAddress, targetPort);
+    }
+
+    /**
+     * Cancel an earlier requested remote port forwarding.
+     * Currently active forwardings will not be affected (e.g., disrupted).
+     * Note that further connection forwarding requests may be received until
+     * this method has returned.
+     *
+     * @param bindPort the allocated port number on the server
+     * @throws IOException if the remote side refuses the cancel request or another low
+     *                     level error occurs (e.g., the underlying connection is closed)
+     */
+    public synchronized void cancelRemotePortForwarding(int bindPort) throws IOException {
+        this.checkConnection();
+
+        cm.requestCancelGlobalForward(bindPort);
+    }
+
+    /**
+     * Provide your own instance of SecureRandom. Can be used, e.g., if you
+     * want to seed the used SecureRandom generator manually.
+     * <p/>
+     * The SecureRandom instance is used during key exchanges, public key authentication,
+     * x11 cookie generation and the like.
+     *
+     * @param rnd a SecureRandom instance
+     */
+    public synchronized void setSecureRandom(SecureRandom rnd) {
+        if(rnd == null) {
+            throw new IllegalArgumentException();
+        }
+        this.generator = rnd;
+    }
+
+    private void checkConnection() throws IllegalStateException {
+        if(tm == null) {
+            throw new IllegalStateException("You need to establish a connection first.");
+        }
+        if(!authenticated) {
+            throw new IllegalStateException("The connection is not authenticated.");
+        }
+    }
+}