/**
* Pools the specified <tt>RawPacket</tt> in order to avoid future allocations and to reduce the
* effects of garbage collection.
*
* @param pkt the <tt>RawPacket</tt> to be offered to {@link #rawPacketPool}
*/
private void poolRawPacket(RawPacket pkt) {
pkt.setBuffer(null);
pkt.setFlags(0);
pkt.setLength(0);
pkt.setOffset(0);
rawPacketPool.offer(pkt);
}
public int write(byte[] buffer, int offset, int length, boolean transform) {
RawPacket pkt = rawPacketArray[0];
if (pkt == null) pkt = new RawPacket();
rawPacketArray[0] = pkt;
byte[] pktBuf = pkt.getBuffer();
if (pktBuf == null || pktBuf.length < length) {
pktBuf = new byte[length];
pkt.setBuffer(pktBuf);
}
System.arraycopy(buffer, offset, pktBuf, 0, length);
pkt.setOffset(0);
pkt.setLength(length);
if (transform) {
PacketTransformer packetTransformer =
isControlStream ? rtcpPacketTransformer : rtpPacketTransformer;
if (packetTransformer != null)
rawPacketArray = packetTransformer.reverseTransform(rawPacketArray);
}
SourceTransferHandler transferHandler;
PushSourceStream pushSourceStream;
try {
if (isControlStream) {
transferHandler = controlTransferHandler;
pushSourceStream = getControlInputStream();
} else {
transferHandler = dataTransferHandler;
pushSourceStream = getDataInputStream();
}
} catch (IOException ioe) {
throw new UndeclaredThrowableException(ioe);
}
for (int i = 0; i < rawPacketArray.length; i++) {
RawPacket packet = rawPacketArray[i];
// keep the first element for reuse
if (i != 0) rawPacketArray[i] = null;
if (packet != null) {
if (isControlStream) pendingControlPacket = packet;
else pendingDataPacket = packet;
if (transferHandler != null) {
transferHandler.transferData(pushSourceStream);
}
}
}
return length;
}
/**
* Creates a new <tt>RawPacket</tt> from a specific <tt>DatagramPacket</tt> in order to have this
* instance receive its packet data through its {@link #read(byte[], int, int)} method. Returns an
* array of <tt>RawPacket</tt> with the created packet as its first element (and <tt>null</tt> for
* the other elements).
*
* <p>Allows extenders to intercept the packet data and possibly filter and/or modify it.
*
* @param datagramPacket the <tt>DatagramPacket</tt> containing the packet data
* @return an array of <tt>RawPacket</tt> containing the <tt>RawPacket</tt> which contains the
* packet data of the specified <tt>DatagramPacket</tt> as its first element.
*/
protected RawPacket[] createRawPacket(DatagramPacket datagramPacket) {
RawPacket[] pkts = rawPacketArrayPool.poll();
if (pkts == null) pkts = new RawPacket[1];
RawPacket pkt = rawPacketPool.poll();
if (pkt == null) pkt = new RawPacket();
pkt.setBuffer(datagramPacket.getData());
pkt.setFlags(0);
pkt.setLength(datagramPacket.getLength());
pkt.setOffset(datagramPacket.getOffset());
pkts[0] = pkt;
return pkts;
}
/**
* Removes the RTX encapsulation from a packet.
*
* @param pkt the packet to remove the RTX encapsulation from.
* @return the original media packet represented by {@code pkt}, or null if we couldn't
* reconstruct the original packet.
*/
private RawPacket deRtx(RawPacket pkt) {
boolean success = false;
if (pkt.getPayloadLength() - pkt.getPaddingSize() < 2) {
// We need at least 2 bytes to read the OSN field.
if (logger.isDebugEnabled()) {
logger.debug("Dropping an incoming RTX packet with padding only: " + pkt);
}
return null;
}
long mediaSsrc = getPrimarySsrc(pkt);
if (mediaSsrc != -1) {
if (rtxAssociatedPayloadType != -1) {
int osn = pkt.getOriginalSequenceNumber();
// Remove the RTX header by moving the RTP header two bytes
// right.
byte[] buf = pkt.getBuffer();
int off = pkt.getOffset();
System.arraycopy(buf, off, buf, off + 2, pkt.getHeaderLength());
pkt.setOffset(off + 2);
pkt.setLength(pkt.getLength() - 2);
pkt.setSSRC((int) mediaSsrc);
pkt.setSequenceNumber(osn);
pkt.setPayloadType(rtxAssociatedPayloadType);
success = true;
} else {
logger.warn(
"RTX packet received, but no APT is defined. Packet "
+ "SSRC "
+ pkt.getSSRCAsLong()
+ ", associated media"
+ " SSRC "
+ mediaSsrc);
}
}
// If we failed to handle the RTX packet, drop it.
return success ? pkt : null;
}
/**
* Creates a {@code RawPacket} which represents the original packet encapsulated in {@code pkt}
* using the RTX format.
*
* @param pkt the packet from which to extract a media packet.
* @return the extracted media packet.
*/
private RawPacket createMediaPacket(RawPacket pkt) {
RawPacket mediaPacket = null;
long rtxSsrc = pkt.getSSRC() & 0xffffffffL;
// We need to know the SSRC paired with rtxSsrc *as seen by the
// receiver (i.e. this.channel)*. However, we only store SSRCs
// that endpoints *send* with.
// We therefore assume that SSRC re-writing has not introduced any
// new SSRCs and therefor the FID mappings known to the senders
// also apply to receivers.
RtpChannel sourceChannel = channel.getContent().findChannelByFidSsrc(rtxSsrc);
if (sourceChannel != null) {
long mediaSsrc = sourceChannel.getFidPairedSsrc(rtxSsrc);
if (mediaSsrc != -1) {
byte apt = sourceChannel.getRtxAssociatedPayloadType();
if (apt != -1) {
mediaPacket = new RawPacket(pkt.getBuffer().clone(), pkt.getOffset(), pkt.getLength());
// Remove the RTX header by moving the RTP header two bytes
// right.
byte[] buf = mediaPacket.getBuffer();
int off = mediaPacket.getOffset();
System.arraycopy(buf, off, buf, off + 2, mediaPacket.getHeaderLength());
mediaPacket.setOffset(off + 2);
mediaPacket.setLength(pkt.getLength() - 2);
mediaPacket.setSSRC((int) mediaSsrc);
mediaPacket.setSequenceNumber(pkt.getOriginalSequenceNumber());
mediaPacket.setPayloadType(apt);
}
}
}
return mediaPacket;
}