recvmsg() — netty Function Reference

Source Code

transport-classes-epoll/src/main/java/io/netty/channel/epoll/EpollDatagramChannel.java lines 714–753

    private boolean recvmsg(EpollRecvByteAllocatorHandle allocHandle,
                            NativeDatagramPacketArray array, ByteBuf byteBuf) throws IOException {
        RecyclableArrayList datagramPackets = null;
        try {
            int writable = byteBuf.writableBytes();

            boolean added = array.addWritable(byteBuf, byteBuf.writerIndex(), writable);
            assert added;

            allocHandle.attemptedBytesRead(writable);

            NativeDatagramPacketArray.NativeDatagramPacket msg = array.packets()[0];

            int bytesReceived = socket.recvmsg(msg);
            if (!msg.hasSender()) {
                allocHandle.lastBytesRead(-1);
                return false;
            }
            byteBuf.writerIndex(bytesReceived);
            InetSocketAddress local = localAddress();
            DatagramPacket packet = msg.newDatagramPacket(byteBuf, local);
            if (!(packet instanceof io.netty.channel.unix.SegmentedDatagramPacket)) {
                processPacket(pipeline(), allocHandle, bytesReceived, packet);
            } else {
                // Its important that we process all received data out of the NativeDatagramPacketArray
                // before we call fireChannelRead(...). This is because the user may call flush()
                // in a channelRead(...) method and so may re-use the NativeDatagramPacketArray again.
                datagramPackets = RecyclableArrayList.newInstance();
                addDatagramPacketToOut(packet, datagramPackets);

                processPacketList(pipeline(), allocHandle, bytesReceived, datagramPackets);
                datagramPackets.recycle();
                datagramPackets = null;
            }

            return true;
        } finally {
            releaseAndRecycle(byteBuf, datagramPackets);
        }
    }