Examples of org.jnetpcap.protocol.tcpip.Tcp$AlternateChecksum

org.jnetpcap.protocol.tcpip.Tcp
The option described in this memo provides a mechanism to negotiate the use of an alternate checksum at connection-establishment time, as well as a mechanism to carry additional checksum information for algorithms that utilize checksums that are longer than 16 bits.
Definition of the option: the TCP Alternate Checksum Request Option may be sent in a SYN segment by a TCP to indicate that the TCP is prepared to both generate and receive checksums based on an alternate algorithm. During communication, the alternate checksum replaces the regular TCP checksum in the checksum field of the TCP header. Should the alternate checksum require more than 2 bytes to transmit, the checksum may either be moved into a TCP Alternate Checksum Data Option and the checksum field of the TCP header be sent as 0, or the data may be split between the header field and the option. Alternate checksums are computed over the same data as the regular TCP checksum.
@author Mark Bednarczyk @author Sly Technologies, Inc.


    InetAddress dst = InetAddress.getByName("201.1.1.1");
    InetAddress src = InetAddress.getByName("192.168.1.1");


    Ip4 ip = packet.getHeader(new Ip4());
    Tcp tcp = packet.getHeader(new Tcp());


    ip.destination(dst.getAddress());
    ip.source(src.getAddress());


    ip.checksum(ip.calculateChecksum());
    tcp.checksum(tcp.calculateChecksum());
    packet.scan(Ethernet.ID);


    System.out.println(packet);
    List<PcapIf> alldevs = new ArrayList<PcapIf>(); // Will be filled with NICs
    StringBuilder errbuf = new StringBuilder(); // For any error msgs

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    assertNotNull(errbuf.toString(), pcap);


    pcap.loop(Pcap.LOOP_INFINATE, new PcapPacketHandler<String>() {
      Ip4 ip = new Ip4();


      Tcp tcp = new Tcp();


      // public void nextPacket(PcapHeader header, JBuffer buffer, String user)
      // {
      public void nextPacket(PcapPacket packet, String user) {


        if (packet.hasHeader(tcp) == false) {
          return;
        }


        // PcapPacket packet = new PcapPacket(header, buffer);


        long f = packet.getFrameNumber();
        assertTrue("#" + f, packet.hasHeader(ip));


        final int crc =
            Checksum.pseudoTcp(packet, ip.getOffset(), tcp.getOffset());


        if (crc != 0 && tcp.checksum() != crc) {
          System.out.println(tcp);
          System.out.printf("#%d: tcp.crc=%x computed=%x\n", f, tcp.checksum(),
              crc);
          // System.out.println(ip.toHexdump());
          // System.out.println(tcp.toHexdump());
          System.exit(0);
        }

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    assertNotNull(errbuf.toString(), pcap);


    pcap.loop(Pcap.LOOP_INFINATE, new PcapPacketHandler<String>() {
      Ip6 ip = new Ip6();


      Tcp tcp = new Tcp();


      public void nextPacket(PcapPacket packet, String user) {


        if (packet.hasHeader(tcp) == false) {
          return;
        }


        // PcapPacket packet = new PcapPacket(header, buffer);


        long f = packet.getFrameNumber();
        assertTrue("#" + f, packet.hasHeader(ip));


        assertTrue("Frame #" + f, tcp.isChecksumValid());
      }


    }, null);
  }

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   */
  public void testTcpOptions() {
    JPacket packet = TestUtils.getPcapPacket(SMALL_IMAP, 1 - 1);
    System.out.println(packet.toString());
    
    Tcp tcp = packet.getHeader(new Tcp());
    Tcp.Timestamp ts = new Tcp.Timestamp();
    
    if (tcp.hasSubHeader(ts)) {
      System.out.printf("tsval=%d tsecr=%d%n", ts.tsval(), ts.tsecr());
    }
  }

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    long pid = sig.getPid();
    ProcMem pm = new ProcMem();
    long base = 0;
    final PcapPacket packet = new PcapPacket(JMemory.POINTER);
    int loop = 0;
    final Tcp tcp = new Tcp();


    final JBufferHandler<Object> handler = new JBufferHandler<Object>() {


      public void nextPacket(PcapHeader header, JBuffer buffer, Object user) {

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    ProcMem pm = new ProcMem();
    long base = 0;


    final PcapPacket packet = new PcapPacket(JMemory.POINTER);
    final PcapPacket.State state = packet.getState();
    final Tcp tcp = new Tcp();
    // final TcpScanner tcpScanner = new TcpScanner();


    final ByteBuffer byteBuffer = ByteBuffer.allocate(8 * 1024);


    final ReferenceQueue<PcapPacket> refQueue =

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Related Classes of org.jnetpcap.protocol.tcpip.Tcp$AlternateChecksum

org.jnetpcap.packet.TestForMemoryLeaks

org.jnetpcap.protocol.TestTcpIp

org.jnetpcap.TestTransmitter

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