/**
* Handles a specific <tt>IOException</tt> which was thrown during the execution of {@link
* #runInConnectThread(DTLSProtocol, TlsPeer, DatagramTransport)} while trying to establish a DTLS
* connection
*
* @param ioe the <tt>IOException</tt> to handle
* @param msg the human-readable message to log about the specified <tt>ioe</tt>
* @param i the number of tries remaining after the current one
* @return <tt>true</tt> if the specified <tt>ioe</tt> was successfully handled; <tt>false</tt>,
* otherwise
*/
private boolean handleRunInConnectThreadException(IOException ioe, String msg, int i) {
// SrtpControl.start(MediaType) starts its associated TransformEngine.
// We will use that mediaType to signal the normal stop then as well
// i.e. we will ignore exception after the procedure to stop this
// PacketTransformer has begun.
if (mediaType == null) return false;
if (ioe instanceof TlsFatalAlert) {
TlsFatalAlert tfa = (TlsFatalAlert) ioe;
short alertDescription = tfa.getAlertDescription();
if (alertDescription == AlertDescription.unexpected_message) {
msg += " Received fatal unexpected message.";
if (i == 0
|| !Thread.currentThread().equals(connectThread)
|| connector == null
|| mediaType == null) {
msg += " Giving up after " + (CONNECT_TRIES - i) + " retries.";
} else {
msg += " Will retry.";
logger.error(msg, ioe);
return true;
}
} else {
msg += " Received fatal alert " + alertDescription + ".";
}
}
logger.error(msg, ioe);
return false;
}
/** Stops this <tt>PacketTransformer</tt>. */
private synchronized void stop() {
if (connectThread != null) connectThread = null;
try {
// The dtlsTransport and _srtpTransformer SHOULD be closed, of
// course. The datagramTransport MUST be closed.
if (dtlsTransport != null) {
try {
dtlsTransport.close();
} catch (IOException ioe) {
logger.error("Failed to (properly) close " + dtlsTransport.getClass(), ioe);
}
dtlsTransport = null;
}
if (_srtpTransformer != null) {
_srtpTransformer.close();
_srtpTransformer = null;
}
} finally {
try {
closeDatagramTransport();
} finally {
notifyAll();
}
}
}
/**
* Closes {@link #datagramTransport} if it is non-<tt>null</tt> and logs and swallows any
* <tt>IOException</tt>.
*/
private void closeDatagramTransport() {
if (datagramTransport != null) {
try {
datagramTransport.close();
} catch (IOException ioe) {
// DatagramTransportImpl has no reason to fail because it is
// merely an adapter of #connector and this PacketTransformer to
// the terms of the Bouncy Castle Crypto API.
logger.error("Failed to (properly) close " + datagramTransport.getClass(), ioe);
}
datagramTransport = null;
}
}
/**
* Sends the data contained in a specific byte array as application data through the DTLS
* connection of this <tt>DtlsPacketTransformer</tt>.
*
* @param buf the byte array containing data to send.
* @param off the offset in <tt>buf</tt> where the data begins.
* @param len the length of data to send.
*/
public void sendApplicationData(byte[] buf, int off, int len) {
DTLSTransport dtlsTransport = this.dtlsTransport;
Throwable throwable = null;
if (dtlsTransport != null) {
try {
dtlsTransport.send(buf, off, len);
} catch (IOException ioe) {
throwable = ioe;
}
} else {
throwable = new NullPointerException("dtlsTransport");
}
if (throwable != null) {
// SrtpControl.start(MediaType) starts its associated
// TransformEngine. We will use that mediaType to signal the normal
// stop then as well i.e. we will ignore exception after the
// procedure to stop this PacketTransformer has begun.
if (mediaType != null && !tlsPeerHasRaisedCloseNotifyWarning) {
logger.error("Failed to send application data over DTLS transport: ", throwable);
}
}
}
/** {@inheritDoc} */
@Override
public RawPacket reverseTransform(RawPacket pkt) {
byte[] buf = pkt.getBuffer();
int off = pkt.getOffset();
int len = pkt.getLength();
if (isDtlsRecord(buf, off, len)) {
if (rtcpmux && Component.RTCP == componentID) {
// This should never happen.
logger.warn(
"Dropping a DTLS record, because it was received on the"
+ " RTCP channel while rtcpmux is in use.");
return null;
}
boolean receive;
synchronized (this) {
if (datagramTransport == null) {
receive = false;
} else {
datagramTransport.queueReceive(buf, off, len);
receive = true;
}
}
if (receive) {
DTLSTransport dtlsTransport = this.dtlsTransport;
if (dtlsTransport == null) {
// The specified pkt looks like a DTLS record and it has
// been consumed for the purposes of the secure channel
// represented by this PacketTransformer.
pkt = null;
} else {
try {
int receiveLimit = dtlsTransport.getReceiveLimit();
int delta = receiveLimit - len;
if (delta > 0) {
pkt.grow(delta);
buf = pkt.getBuffer();
off = pkt.getOffset();
len = pkt.getLength();
} else if (delta < 0) {
pkt.shrink(-delta);
buf = pkt.getBuffer();
off = pkt.getOffset();
len = pkt.getLength();
}
int received = dtlsTransport.receive(buf, off, len, DTLS_TRANSPORT_RECEIVE_WAITMILLIS);
if (received <= 0) {
// No application data was decoded.
pkt = null;
} else {
delta = len - received;
if (delta > 0) pkt.shrink(delta);
}
} catch (IOException ioe) {
pkt = null;
// SrtpControl.start(MediaType) starts its associated
// TransformEngine. We will use that mediaType to signal
// the normal stop then as well i.e. we will ignore
// exception after the procedure to stop this
// PacketTransformer has begun.
if (mediaType != null && !tlsPeerHasRaisedCloseNotifyWarning) {
logger.error("Failed to decode a DTLS record!", ioe);
}
}
}
} else {
// The specified pkt looks like a DTLS record but it is
// unexpected in the current state of the secure channel
// represented by this PacketTransformer. This PacketTransformer
// has not been started (successfully) or has been closed.
pkt = null;
}
} else if (transformEngine.isSrtpDisabled()) {
// In pure DTLS mode only DTLS records pass through.
pkt = null;
} else {
// DTLS-SRTP has not been initialized yet or has failed to
// initialize.
SinglePacketTransformer srtpTransformer = waitInitializeAndGetSRTPTransformer();
if (srtpTransformer != null) pkt = srtpTransformer.reverseTransform(pkt);
else if (DROP_UNENCRYPTED_PKTS) pkt = null;
// XXX Else, it is our explicit policy to let the received packet
// pass through and rely on the SrtpListener to notify the user that
// the session is not secured.
}
return pkt;
}