/** {@inheritDoc} */
@Override
public RawPacket transform(RawPacket pkt) {
byte[] buf = pkt.getBuffer();
int off = pkt.getOffset();
int len = pkt.getLength();
// If the specified pkt represents a DTLS record, then it should pass
// through this PacketTransformer (e.g. it has been sent through
// DatagramTransportImpl).
if (isDtlsRecord(buf, off, len)) return pkt;
// SRTP
if (!transformEngine.isSrtpDisabled()) {
// DTLS-SRTP has not been initialized yet or has failed to
// initialize.
SinglePacketTransformer srtpTransformer = waitInitializeAndGetSRTPTransformer();
if (srtpTransformer != null) pkt = srtpTransformer.transform(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.
}
// Pure/non-SRTP DTLS
else {
// The specified pkt will pass through this PacketTransformer only
// if it gets transformed into a DTLS record.
pkt = null;
sendApplicationData(buf, off, len);
}
return pkt;
}
/**
* 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();
}
/** {@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;
}