예제 #1
0
  /**
   * Process a packet that has been received and matches getType()
   *
   * @param skbuf
   * @param deviceAPI
   * @throws SocketException
   */
  public void receive(SocketBuffer skbuf, NetDeviceAPI deviceAPI) throws SocketException {

    // Update statistics
    stat.ipackets.inc();

    // Get IP header
    final IPv4Header hdr = new IPv4Header(skbuf);
    if (!hdr.isChecksumOk()) {
      stat.badsum.inc();
      return;
    }
    // Set the header object in the buffer-field
    skbuf.setNetworkLayerHeader(hdr);

    // Remove header from skbuf-data
    skbuf.pull(hdr.getLength());
    // Trim the end of the message, to we have a valid length
    skbuf.trim(hdr.getDataLength());

    // Now test if the size of the buffer equals the datalength in the
    // header, if now ignore the packet
    if (skbuf.getSize() < hdr.getDataLength()) {
      stat.badlen.inc();
      return;
    }

    // Update the ARP cache for the source address
    updateARPCache(skbuf.getLinkLayerHeader().getSourceAddress(), hdr.getSourceAddress());

    // Get my IP address
    final IPv4ProtocolAddressInfo myAddrInfo =
        (IPv4ProtocolAddressInfo) deviceAPI.getProtocolAddressInfo(getProtocolID());
    if (myAddrInfo == null) {
      stat.nodevaddr.inc();
    }

    // Should I process this packet, or is it for somebody else?
    final IPv4Address dstAddr = hdr.getDestination();
    final boolean shouldProcess;
    if (myAddrInfo != null) {
      shouldProcess = myAddrInfo.contains(dstAddr);
    } else {
      // I don't have an IP address yet, if the linklayer says
      // it is for me, we'll process it, otherwise we'll drop it.
      shouldProcess = !skbuf.getLinkLayerHeader().getDestinationAddress().isBroadcast();
    }
    if (!shouldProcess) {
      // log.debug("IPPacket not for me, ignoring (dst=" + dstAddr + ")");
      return;
    }

    // Is it a fragment?
    if (hdr.isFragment()) {
      // Yes it is a fragment
      stat.fragments.inc();
      deliverFragment(hdr, skbuf);
    } else {
      // It is a complete packet, find the protocol handler
      // and let it do the rest
      deliver(hdr, skbuf);
    }

    // Do a cleanup of the fragmentlist from time to time
    final long now = System.currentTimeMillis();
    if ((now - lastFragmentCleanup) >= (IP_FRAGTIMEOUT * 2)) {
      removeDeadFragments();
    }
  }
예제 #2
0
  /** @see org.jnode.net.TransportLayer#receive(org.jnode.net.SocketBuffer) */
  public void receive(SocketBuffer skbuf) throws SocketException {

    // Increment stats
    stat.ipackets.inc();

    // Get the IP header
    final IPv4Header ipHdr = (IPv4Header) skbuf.getNetworkLayerHeader();

    // Read the TCP header
    final TCPHeader hdr = new TCPHeader(skbuf);

    // Set the TCP header in the buffer-field
    skbuf.setTransportLayerHeader(hdr);
    // Remove the TCP header from the head of the buffer
    skbuf.pull(hdr.getLength());
    // Trim the buffer up to the length in the TCP header
    skbuf.trim(hdr.getDataLength());

    if (!hdr.isChecksumOk()) {
      if (DEBUG) {
        if (log.isDebugEnabled()) {
          log.debug("Receive: badsum: " + hdr);
        }
      }
      stat.badsum.inc();
    } else {
      if (DEBUG) {
        if (log.isDebugEnabled()) {
          log.debug("Receive: " + hdr);
        }
      }

      // Find the corresponding control block
      final TCPControlBlock cb =
          (TCPControlBlock)
              controlBlocks.lookup(
                  ipHdr.getSource(),
                  hdr.getSrcPort(),
                  ipHdr.getDestination(),
                  hdr.getDstPort(),
                  true);
      if (cb == null) {
        final boolean ack = hdr.isFlagAcknowledgeSet();
        final boolean rst = hdr.isFlagResetSet();

        stat.noport.inc();

        // Port unreachable
        if (ack && rst) {
          // the source is also unreachable
          log.debug(
              "Dropping segment due to: connection refused as the source is also unreachable");
        } else {
          processPortUnreachable(ipHdr, hdr);
        }
      } else {
        // Let the cb handle the receive
        cb.receive(hdr, skbuf);
      }
    }
  }