Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/io/PcapHandleReader.java

   1 package edu.uci.iotproject.io;
   2
   3 import edu.uci.iotproject.analysis.PcapPacketFilter;
   4 import org.pcap4j.core.*;
   5
   6 import java.io.EOFException;
   7 import java.util.concurrent.TimeoutException;
   8
   9 /**
  10  * Reads packets from a {@link PcapHandle} (online or offline) and delivers those packets that pass the test exercised
  11  * by the provided {@link PcapPacketFilter} onto the provided {@link PacketListener}s.
  12  *
  13  * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
  14  * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
  15  */
  16 public class PcapHandleReader {
  17
  18     private final PcapPacketFilter mPacketFilter;
  19     private final PcapHandle mHandle;
  20     private final PacketListener[] mPacketListeners;
  21
  22     /**
  23      * Create a {@code PcapHandleReader}.
  24      * @param handle An <em>open</em> {@link PcapHandle} that packets will be read from.
  25      * @param packetFilter A {@link PcapPacketFilter} that dictates which of the packets read from {@code handle} should
  26      *                     be delivered to {@code packetListeners}. Note that while a value of {@code null} is not
  27      *                     permitted here, the caller can instead simply provide an implementation that always returns
  28      *                     {@code true} if they want to include all packets read from {@code handle}.
  29      * @param packetListeners One or more {@link PacketListener}s to which those packets read from {@code handle} that
  30      *                        pass through {@code packetFilter} are delivered.
  31      */
  32     public PcapHandleReader(PcapHandle handle, PcapPacketFilter packetFilter, PacketListener... packetListeners) {
  33         mHandle = handle;
  34         mPacketFilter = packetFilter;
  35         mPacketListeners = packetListeners;
  36     }
  37
  38
  39     /**
  40      * Start reading (and filtering) packets from the provided {@link PcapHandle}.
  41      * @throws PcapNativeException if an error occurs in the pcap native library.
  42      * @throws NotOpenException if the provided {@code PcapHandle} is not open.
  43      * @throws TimeoutException if packets are being read from a live capture and the timeout expired.
  44      */
  45     public void readFromHandle() throws PcapNativeException, NotOpenException, TimeoutException {
  46         int outOfOrderPackets = 0;
  47         try {
  48             PcapPacket prevPacket = null;
  49             PcapPacket packet;
  50             while ((packet = mHandle.getNextPacketEx()) != null) {
  51                 if (prevPacket != null && packet.getTimestamp().isBefore(prevPacket.getTimestamp())) {
  52                     outOfOrderPackets++;
  53                     /*
  54                     // Fail early if assumption doesn't hold.
  55                     mHandle.close();
  56                     throw new AssertionError("Packets not in ascending temporal order");
  57                     */
  58                 }
  59                 if (mPacketFilter.shouldIncludePacket(packet)) {
  60                     // Packet accepted for inclusion; deliver it to observing client code.
  61                     for (PacketListener consumer : mPacketListeners) {
  62                         consumer.gotPacket(packet);
  63                     }
  64                 }
  65                 prevPacket = packet;
  66             }
  67         } catch (EOFException eof) {
  68             // Reached end of file. All good.
  69             System.out.println(String.format("%s: finished reading pcap file", getClass().getSimpleName()));
  70         }
  71         if (outOfOrderPackets > 0) {
  72             System.err.println(
  73                     String.format("[[[ %s: %d packets appeared out of order (with regards to their timestamps) ]]]",
  74                             getClass().getSimpleName(), outOfOrderPackets));
  75         }
  76         mHandle.close();
  77     }
  78
  79 }