package ch.ethz.ssh2.transport;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import java.security.SecureRandom;
import java.util.Vector;
import ch.ethz.ssh2.ConnectionInfo;
import ch.ethz.ssh2.DHGexParameters;
import ch.ethz.ssh2.ServerHostKeyVerifier;
import ch.ethz.ssh2.crypto.CryptoWishList;
import ch.ethz.ssh2.crypto.cipher.BlockCipher;
import ch.ethz.ssh2.crypto.digest.MAC;
import ch.ethz.ssh2.log.Logger;
import ch.ethz.ssh2.packets.PacketDisconnect;
import ch.ethz.ssh2.packets.Packets;
import ch.ethz.ssh2.packets.TypesReader;
import ch.ethz.ssh2.util.Tokenizer;
/*
* Yes, the "standard" is a big mess. On one side, the say that arbitary channel
* packets are allowed during kex exchange, on the other side we need to blindly
* ignore the next _packet_ if the KEX guess was wrong. Where do we know from that
* the next packet is not a channel data packet? Yes, we could check if it is in
* the KEX range. But the standard says nothing about this. The OpenSSH guys
* block local "normal" traffic during KEX. That's fine - however, they assume
* that the other side is doing the same. During re-key, if they receive traffic
* other than KEX, they become horribly irritated and kill the connection. Since
* we are very likely going to communicate with OpenSSH servers, we have to play
* the same game - even though we could do better.
*
* btw: having stdout and stderr on the same channel, with a shared window, is
* also a VERY good idea... =(
*/
/**
* TransportManager.
*
* @author Christian Plattner, plattner@inf.ethz.ch
* @version $Id: TransportManager.java,v 1.13 2006/02/14 19:43:15 cplattne Exp $
*/
public class TransportManager
{
private static final Logger log = Logger.getLogger(TransportManager.class);
class HandlerEntry
{
MessageHandler mh;
int low;
int high;
}
private final Vector asynchronousQueue = new Vector();
private Thread asynchronousThread = null;
class AsynchronousWorker extends Thread
{
public void run()
{
while (true)
{
byte[] msg = null;
synchronized (asynchronousQueue)
{
if (asynchronousQueue.size() == 0)
{
/* After the queue is empty for about 2 seconds, stop this thread */
try
{
asynchronousQueue.wait(2000);
}
catch (InterruptedException e)
{
/* OKOK, if somebody interrupts us, then we may die earlier. */
}
if (asynchronousQueue.size() == 0)
{
asynchronousThread = null;
return;
}
}
msg = (byte[]) asynchronousQueue.remove(0);
}
/* The following invocation may throw an IOException.
* There is no point in handling it - it simply means
* that the connection has a problem and we should stop
* sending asynchronously messages. We do not need to signal that
* we have exited (asynchronousThread = null): further
* messages in the queue cannot be sent by this or any
* other thread.
* Other threads will sooner or later (when receiving or
* sending the next message) get the same IOException and
* get to the same conclusion.
*/
try
{
sendMessage(msg);
}
catch (IOException e)
{
return;
}
}
}
}
String hostname;
int port;
final Socket sock = new Socket();
Object connectionSemaphore = new Object();
boolean flagKexOngoing = false;
boolean connectionClosed = false;
Throwable reasonClosedCause = null;
Vector kexBlockedSendQueue = new Vector(10);
TransportConnection tc;
KexManager km;
Vector messageHandlers = new Vector();
Thread receiveThread;
/**
* There were reports that there are JDKs which use
* the resolver even though one supplies a dotted IP
* address in the Socket constructor. That is why we
* try to generate the InetAdress "by hand".
*
* @param host
* @return the InetAddress
* @throws UnknownHostException
*/
private InetAddress createInetAddress(String host) throws UnknownHostException
{
/* Check if it is a dotted IP4 address */
InetAddress addr = parseIPv4Address(host);
if (addr != null)
return addr;
return InetAddress.getByName(host);
}
private InetAddress parseIPv4Address(String host) throws UnknownHostException
{
if (host == null)
return null;
String[] quad = Tokenizer.parseTokens(host, '.');
if ((quad == null) || (quad.length != 4))
return null;
byte[] addr = new byte[4];
for (int i = 0; i < 4; i++)
{
int part = 0;
if ((quad[i].length() == 0) || (quad[i].length() > 3))
return null;
for (int k = 0; k < quad[i].length(); k++)
{
char c = quad[i].charAt(k);
/* No, Character.isDigit is not the same */
if ((c < '0') || (c > '9'))
return null;
part = part * 10 + (c - '0');
}
if (part > 255) /* 300.1.2.3 is invalid =) */
return null;
addr[i] = (byte) part;
}
return InetAddress.getByAddress(addr);
}
public TransportManager(String host, int port) throws IOException
{
this.hostname = host;
this.port = port;
}
public int getPacketOverheadEstimate()
{
return tc.getPacketOverheadEstimate();
}
public void setTcpNoDelay(boolean state) throws IOException
{
sock.setTcpNoDelay(state);
}
public void setSoTimeout(int timeout) throws IOException
{
sock.setSoTimeout(timeout);
}
public ConnectionInfo getConnectionInfo(int kexNumber) throws IOException
{
return km.getOrWaitForConnectionInfo(kexNumber);
}
public Throwable getReasonClosedCause()
{
synchronized (connectionSemaphore)
{
return reasonClosedCause;
}
}
public byte[] getSessionIdentifier()
{
return km.sessionId;
}
public void close(Throwable cause, boolean useDisconnectPacket)
{
if (useDisconnectPacket == false)
{
/* OK, hard shutdown - do not aquire the semaphore,
* perhaps somebody is inside (and waits until the remote
* side is ready to accept new data). */
try
{
sock.close();
}
catch (IOException ignore)
{
}
/* OK, whoever tried to send data, should now agree that
* there is no point in further waiting =)
* It is save now to aquire the semaphore.
*/
}
synchronized (connectionSemaphore)
{
if (connectionClosed)
return;
if (useDisconnectPacket == true)
{
try
{
byte[] msg = new PacketDisconnect(Packets.SSH_DISCONNECT_BY_APPLICATION, cause.getMessage(), "")
.getPayload();
if (tc != null)
tc.sendMessage(msg);
}
catch (IOException ignore)
{
}
try
{
sock.close();
}
catch (IOException ignore)
{
}
}
connectionClosed = true;
reasonClosedCause = cause; /* may be null */
connectionSemaphore.notifyAll();
}
}
public void initialize(CryptoWishList cwl, ServerHostKeyVerifier verifier, DHGexParameters dhgex,
int connectTimeout, SecureRandom rnd) throws IOException
{
/* See the comment for createInetAddress() */
InetAddress addr = createInetAddress(hostname);
sock.connect(new InetSocketAddress(addr, port), connectTimeout);
sock.setSoTimeout(0);
tc = new TransportConnection(sock.getInputStream(), sock.getOutputStream(), rnd);
ClientServerHello csh = new ClientServerHello(sock.getInputStream(), sock.getOutputStream());
km = new KexManager(this, csh, cwl, hostname, port, verifier, rnd);
km.initiateKEX(cwl, dhgex);
receiveThread = new Thread(new Runnable()
{
public void run()
{
try
{
receiveLoop();
}
catch (IOException e)
{
close(e, false);
if (log.isEnabled())
log.log(10, "Receive thread: error in receiveLoop: " + e.getMessage());
}
if (log.isEnabled())
log.log(50, "Receive thread: back from receiveLoop");
/* Tell all handlers that it is time to say goodbye */
if (km != null)
{
try
{
km.handleMessage(null, 0);
}
catch (IOException e)
{
}
}
for (int i = 0; i < messageHandlers.size(); i++)
{
HandlerEntry he = (HandlerEntry) messageHandlers.elementAt(i);
try
{
he.mh.handleMessage(null, 0);
}
catch (Exception ignore)
{
}
}
}
});
receiveThread.setDaemon(true);
receiveThread.start();
}
public void registerMessageHandler(MessageHandler mh, int low, int high)
{
HandlerEntry he = new HandlerEntry();
he.mh = mh;
he.low = low;
he.high = high;
synchronized (messageHandlers)
{
messageHandlers.addElement(he);
}
}
public void removeMessageHandler(MessageHandler mh, int low, int high)
{
synchronized (messageHandlers)
{
for (int i = 0; i < messageHandlers.size(); i++)
{
HandlerEntry he = (HandlerEntry) messageHandlers.elementAt(i);
if ((he.mh == mh) && (he.low == low) && (he.high == high))
{
messageHandlers.removeElementAt(i);
break;
}
}
}
}
public void sendKexMessage(byte[] msg) throws IOException
{
synchronized (connectionSemaphore)
{
if (connectionClosed)
{
throw (IOException) new IOException("Sorry, this connection is closed.").initCause(reasonClosedCause);
}
flagKexOngoing = true;
try
{
tc.sendMessage(msg);
}
catch (IOException e)
{
close(e, false);
throw e;
}
}
}
public void kexFinished() throws IOException
{
synchronized (connectionSemaphore)
{
flagKexOngoing = false;
for (int i = 0; i < kexBlockedSendQueue.size(); i++)
{
tc.sendMessage((byte[]) kexBlockedSendQueue.elementAt(i));
}
connectionSemaphore.notifyAll();
}
}
public void forceKeyExchange(CryptoWishList cwl, DHGexParameters dhgex) throws IOException
{
km.initiateKEX(cwl, dhgex);
}
public void changeRecvCipher(BlockCipher bc, MAC mac)
{
tc.changeRecvCipher(bc, mac);
}
public void changeSendCipher(BlockCipher bc, MAC mac)
{
tc.changeSendCipher(bc, mac);
}
public void sendAsynchronousMessage(byte[] msg) throws IOException
{
synchronized (asynchronousQueue)
{
asynchronousQueue.addElement(msg);
/* This limit should be flexible enough. We need this, otherwise the peer
* can flood us with global requests (and other stuff where we have to reply
* with an asynchronous message) and (if the server just sends data and does not
* read what we send) this will probably put us in a low memory situation
* (our send queue would grow and grow and...) */
if (asynchronousQueue.size() > 100)
throw new IOException("Error: the peer is not consuming our asynchronous replies.");
/* Check if we have an asynchronous sending thread */
if (asynchronousThread == null)
{
asynchronousThread = new AsynchronousWorker();
asynchronousThread.setDaemon(true);
asynchronousThread.start();
/* The thread will stop after 2 seconds of inactivity (i.e., empty queue) */
}
}
}
public void sendMessage(byte[] msg) throws IOException
{
synchronized (connectionSemaphore)
{
while (true)
{
if (connectionClosed)
{
throw (IOException) new IOException("Sorry, this connection is closed.")
.initCause(reasonClosedCause);
}
if (flagKexOngoing == false)
break;
if (Thread.currentThread() == receiveThread)
{
// Never block the receive thread
// Use a queue for non-KEX reply packets
// which were generated in the receive thread
kexBlockedSendQueue.addElement(msg);
return;
}
try
{
connectionSemaphore.wait();
}
catch (InterruptedException e)
{
}
}
try
{
tc.sendMessage(msg);
}
catch (IOException e)
{
close(e, false);
throw e;
}
}
}
public void receiveLoop() throws IOException
{
byte[] msg = new byte[35000];
while (true)
{
int msglen = tc.receiveMessage(msg, 0, msg.length);
int type = msg[0] & 0xff;
if (type == Packets.SSH_MSG_IGNORE)
continue;
if (type == Packets.SSH_MSG_DEBUG)
{
if (log.isEnabled())
{
TypesReader tr = new TypesReader(msg, 0, msglen);
tr.readByte();
tr.readBoolean();
StringBuffer debugMessageBuffer = new StringBuffer();
debugMessageBuffer.append(tr.readString("UTF-8"));
for (int i = 0; i < debugMessageBuffer.length(); i++)
{
char c = debugMessageBuffer.charAt(i);
if ((c >= 32) && (c <= 126))
continue;
debugMessageBuffer.setCharAt(i, '\uFFFD');
}
log.log(50, "DEBUG Message from remote: '" + debugMessageBuffer.toString() + "'");
}
continue;
}
if (type == Packets.SSH_MSG_UNIMPLEMENTED)
{
throw new IOException("Peer sent UNIMPLEMENTED message, that should not happen.");
}
if (type == Packets.SSH_MSG_DISCONNECT)
{
TypesReader tr = new TypesReader(msg, 0, msglen);
tr.readByte();
int reason_code = tr.readUINT32();
StringBuffer reasonBuffer = new StringBuffer();
reasonBuffer.append(tr.readString("UTF-8"));
/*
* Do not get fooled by servers that send abnormal long error
* messages
*/
if (reasonBuffer.length() > 255)
{
reasonBuffer.setLength(255);
reasonBuffer.setCharAt(254, '.');
reasonBuffer.setCharAt(253, '.');
reasonBuffer.setCharAt(252, '.');
}
/*
* Also, check that the server did not send charcaters that may
* screw up the receiver -> restrict to reasonable US-ASCII
* subset -> "printable characters" (ASCII 32 - 126). Replace
* all others with 0xFFFD (UNICODE replacement character).
*/
for (int i = 0; i < reasonBuffer.length(); i++)
{
char c = reasonBuffer.charAt(i);
if ((c >= 32) && (c <= 126))
continue;
reasonBuffer.setCharAt(i, '\uFFFD');
}
throw new IOException("Peer sent DISCONNECT message (reason code " + reason_code + "): "
+ reasonBuffer.toString());
}
/*
* Is it a KEX Packet?
*/
if ((type == Packets.SSH_MSG_KEXINIT) || (type == Packets.SSH_MSG_NEWKEYS)
|| ((type >= 30) && (type <= 49)))
{
km.handleMessage(msg, msglen);
continue;
}
MessageHandler mh = null;
for (int i = 0; i < messageHandlers.size(); i++)
{
HandlerEntry he = (HandlerEntry) messageHandlers.elementAt(i);
if ((he.low <= type) && (type <= he.high))
{
mh = he.mh;
break;
}
}
if (mh == null)
throw new IOException("Unexpected SSH message (type " + type + ")");
mh.handleMessage(msg, msglen);
}
}
}