/**
* 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;
}
/**
* Gets the {@code SRTPTransformer} used by this instance. If {@link #_srtpTransformer} does not
* exist (yet) and the state of this instance indicates that its initialization is in progess,
* then blocks until {@code _srtpTransformer} is initialized and returns it.
*
* @return the {@code SRTPTransformer} used by this instance
*/
private SinglePacketTransformer waitInitializeAndGetSRTPTransformer() {
SinglePacketTransformer srtpTransformer = _srtpTransformer;
if (srtpTransformer != null) return srtpTransformer;
if (rtcpmux && Component.RTCP == componentID) return initializeSRTCPTransformerFromRtp();
// XXX It is our explicit policy to rely on the SrtpListener to notify
// the user that the session is not secure. Unfortunately, (1) the
// SrtpListener is not supported by this DTLS SrtpControl implementation
// and (2) encrypted packets may arrive soon enough to be let through
// while _srtpTransformer is still initializing. Consequently, we will
// block and wait for _srtpTransformer to initialize.
boolean interrupted = false;
try {
synchronized (this) {
do {
srtpTransformer = _srtpTransformer;
if (srtpTransformer != null) break; // _srtpTransformer is initialized
if (connectThread == null) {
// Though _srtpTransformer is NOT initialized, there is
// no point in waiting because there is no one to
// initialize it.
break;
}
try {
// It does not really matter (enough) how much we wait
// here because we wait in a loop.
long timeout = CONNECT_TRIES * CONNECT_RETRY_INTERVAL;
wait(timeout);
} catch (InterruptedException ie) {
interrupted = true;
}
} while (true);
}
} finally {
if (interrupted) Thread.currentThread().interrupt();
}
return srtpTransformer;
}
/**
* Determines whether {@link #runInConnectThread(DTLSProtocol, TlsPeer, DatagramTransport)} is to
* try to establish a DTLS connection.
*
* @param i the number of tries remaining after the current one
* @param datagramTransport
* @return <tt>true</tt> to try to establish a DTLS connection; otherwise, <tt>false</tt>
*/
private boolean enterRunInConnectThreadLoop(int i, DatagramTransport datagramTransport) {
if (i < 0 || i > CONNECT_TRIES) {
return false;
} else {
Thread currentThread = Thread.currentThread();
synchronized (this) {
if (i > 0 && i < CONNECT_TRIES - 1) {
boolean interrupted = false;
try {
wait(CONNECT_RETRY_INTERVAL);
} catch (InterruptedException ie) {
interrupted = true;
}
if (interrupted) currentThread.interrupt();
}
return currentThread.equals(this.connectThread)
&& datagramTransport.equals(this.datagramTransport);
}
}
}
/**
* Runs in {@link #connectThread} to initialize {@link #dtlsTransport}.
*
* @param dtlsProtocol
* @param tlsPeer
* @param datagramTransport
*/
private void runInConnectThread(
DTLSProtocol dtlsProtocol, TlsPeer tlsPeer, DatagramTransport datagramTransport) {
DTLSTransport dtlsTransport = null;
final boolean srtp = !transformEngine.isSrtpDisabled();
int srtpProtectionProfile = 0;
TlsContext tlsContext = null;
// DTLS client
if (dtlsProtocol instanceof DTLSClientProtocol) {
DTLSClientProtocol dtlsClientProtocol = (DTLSClientProtocol) dtlsProtocol;
TlsClientImpl tlsClient = (TlsClientImpl) tlsPeer;
for (int i = CONNECT_TRIES - 1; i >= 0; i--) {
if (!enterRunInConnectThreadLoop(i, datagramTransport)) break;
try {
dtlsTransport = dtlsClientProtocol.connect(tlsClient, datagramTransport);
break;
} catch (IOException ioe) {
if (!handleRunInConnectThreadException(
ioe, "Failed to connect this DTLS client to a DTLS" + " server!", i)) {
break;
}
}
}
if (dtlsTransport != null && srtp) {
srtpProtectionProfile = tlsClient.getChosenProtectionProfile();
tlsContext = tlsClient.getContext();
}
}
// DTLS server
else if (dtlsProtocol instanceof DTLSServerProtocol) {
DTLSServerProtocol dtlsServerProtocol = (DTLSServerProtocol) dtlsProtocol;
TlsServerImpl tlsServer = (TlsServerImpl) tlsPeer;
for (int i = CONNECT_TRIES - 1; i >= 0; i--) {
if (!enterRunInConnectThreadLoop(i, datagramTransport)) break;
try {
dtlsTransport = dtlsServerProtocol.accept(tlsServer, datagramTransport);
break;
} catch (IOException ioe) {
if (!handleRunInConnectThreadException(
ioe, "Failed to accept a connection from a DTLS client!", i)) {
break;
}
}
}
if (dtlsTransport != null && srtp) {
srtpProtectionProfile = tlsServer.getChosenProtectionProfile();
tlsContext = tlsServer.getContext();
}
} else {
// It MUST be either a DTLS client or a DTLS server.
throw new IllegalStateException("dtlsProtocol");
}
SinglePacketTransformer srtpTransformer =
(dtlsTransport == null || !srtp)
? null
: initializeSRTPTransformer(srtpProtectionProfile, tlsContext);
boolean closeSRTPTransformer;
synchronized (this) {
if (Thread.currentThread().equals(this.connectThread)
&& datagramTransport.equals(this.datagramTransport)) {
this.dtlsTransport = dtlsTransport;
_srtpTransformer = srtpTransformer;
notifyAll();
}
closeSRTPTransformer = (_srtpTransformer != srtpTransformer);
}
if (closeSRTPTransformer && srtpTransformer != null) srtpTransformer.close();
}