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handlerRemoved() — netty Function Reference

Architecture documentation for the handlerRemoved() function in PcapWriteHandler.java from the netty codebase.

Function java Buffer Allocators calls 3

Entity Profile

Dependency Diagram

graph TD
  83e8cd99_fb62_b9e8_70a4_3ee322e6c838["handlerRemoved()"]
  59f0289b_ecfd_de3c_3397_4cf08e2047d1["PcapWriteHandler"]
  83e8cd99_fb62_b9e8_70a4_3ee322e6c838 -->|defined in| 59f0289b_ecfd_de3c_3397_4cf08e2047d1
  bbfbdddd_98c4_8181_5429_a45dee375189["completeTCPWrite()"]
  83e8cd99_fb62_b9e8_70a4_3ee322e6c838 -->|calls| bbfbdddd_98c4_8181_5429_a45dee375189
  89999839_bf9a_67ff_18ff_46d98e911624["incrementUintSegmentNumber()"]
  83e8cd99_fb62_b9e8_70a4_3ee322e6c838 -->|calls| 89999839_bf9a_67ff_18ff_46d98e911624
  5c216ebb_cca2_4b62_0ccb_54f1456bc752["close()"]
  83e8cd99_fb62_b9e8_70a4_3ee322e6c838 -->|calls| 5c216ebb_cca2_4b62_0ccb_54f1456bc752
  style 83e8cd99_fb62_b9e8_70a4_3ee322e6c838 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

handler/src/main/java/io/netty/handler/pcap/PcapWriteHandler.java lines 616–658

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {

        // If `isTCP` is true and state is WRITING, then we'll simulate a `FIN` flow.
        if (channelType == ChannelType.TCP && state.get() == State.WRITING) {
            logger.debug("Starting Fake TCP FIN+ACK Flow to close connection");

            ByteBufAllocator byteBufAllocator = ctx.alloc();
            ByteBuf tcpBuf = byteBufAllocator.buffer();

            try {
                long initiatorSegmentNumber = isServerPipeline? receiveSegmentNumber : sendSegmentNumber;
                long initiatorAckNumber = isServerPipeline? sendSegmentNumber : receiveSegmentNumber;
                // Write FIN+ACK with Normal Source and Destination Address
                TCPPacket.writePacket(tcpBuf, null, initiatorSegmentNumber, initiatorAckNumber, initiatorAddr.getPort(),
                                      handlerAddr.getPort(), TCPPacket.TCPFlag.FIN, TCPPacket.TCPFlag.ACK);
                completeTCPWrite(initiatorAddr, handlerAddr, tcpBuf, byteBufAllocator, ctx);

                // Write FIN+ACK with Reversed Source and Destination Address
                TCPPacket.writePacket(tcpBuf, null, initiatorAckNumber, initiatorSegmentNumber, handlerAddr.getPort(),
                                      initiatorAddr.getPort(), TCPPacket.TCPFlag.FIN, TCPPacket.TCPFlag.ACK);
                completeTCPWrite(handlerAddr, initiatorAddr, tcpBuf, byteBufAllocator, ctx);

                // Increment by 1 when responding to FIN
                sendSegmentNumber = incrementUintSegmentNumber(sendSegmentNumber, 1);
                receiveSegmentNumber = incrementUintSegmentNumber(receiveSegmentNumber, 1);
                initiatorSegmentNumber = isServerPipeline? receiveSegmentNumber : sendSegmentNumber;
                initiatorAckNumber = isServerPipeline? sendSegmentNumber : receiveSegmentNumber;

                // Write ACK with Normal Source and Destination Address
                TCPPacket.writePacket(tcpBuf, null, initiatorSegmentNumber, initiatorAckNumber,
                                      initiatorAddr.getPort(), handlerAddr.getPort(), TCPPacket.TCPFlag.ACK);
                completeTCPWrite(initiatorAddr, handlerAddr, tcpBuf, byteBufAllocator, ctx);
            } finally {
                tcpBuf.release();
            }

            logger.debug("Finished Fake TCP FIN+ACK Flow to close connection");
        }

        close();
        super.handlerRemoved(ctx);
    }

Domain

Subdomains

Defined In

Calls

Source

Frequently Asked Questions

What does handlerRemoved() do?
handlerRemoved() is a function in the netty codebase, defined in handler/src/main/java/io/netty/handler/pcap/PcapWriteHandler.java.
Where is handlerRemoved() defined?
handlerRemoved() is defined in handler/src/main/java/io/netty/handler/pcap/PcapWriteHandler.java at line 616.
What does handlerRemoved() call?
handlerRemoved() calls 3 function(s): close, completeTCPWrite, incrementUintSegmentNumber.

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