Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/analysis/TcpConversationUtils.java

   1 package edu.uci.iotproject.analysis;
   2
   3 import edu.uci.iotproject.Conversation;
   4 import edu.uci.iotproject.util.PcapPacketUtils;
   5 import org.pcap4j.core.PcapPacket;
   6 import org.pcap4j.packet.IpV4Packet;
   7 import org.pcap4j.packet.TcpPacket;
   8
   9 import java.util.ArrayList;
  10 import java.util.List;
  11
  12 /**
  13  * TODO add class documentation.
  14  *
  15  * @author Janus Varmarken
  16  */
  17 public class TcpConversationUtils {
  18
  19     public static List<PcapPacketPair> extractPacketPairs(Conversation conv) {
  20         List<PcapPacket> packets = conv.getPackets();
  21         List<PcapPacketPair> pairs = new ArrayList<>();
  22         int i = 0;
  23         while (i < packets.size()) {
  24             PcapPacket p1 = packets.get(i);
  25             String p1SrcIp = p1.get(IpV4Packet.class).getHeader().getSrcAddr().getHostAddress();
  26             int p1SrcPort = p1.get(TcpPacket.class).getHeader().getSrcPort().valueAsInt();
  27             if (i+1 < packets.size()) {
  28                 PcapPacket p2 = packets.get(i+1);
  29                 if (PcapPacketUtils.isSource(p2, p1SrcIp, p1SrcPort)) {
  30                     // Two packets in a row going in the same direction -> create one item pair for p1
  31                     pairs.add(new PcapPacketPair(p1, null));
  32                     // Advance one packet as the following two packets may form a valid two-item pair.
  33                     i++;
  34                 } else {
  35                     // The two packets form a response-reply pair, create two-item pair.
  36                     pairs.add(new PcapPacketPair(p1, p2));
  37                     // Advance two packets as we have already processed the packet at index i+1 in order to create the pair.
  38                     i += 2;
  39                 }
  40             } else {
  41                 // Last packet of conversation => one item pair
  42                 pairs.add(new PcapPacketPair(p1, null));
  43                 // Advance i to ensure termination.
  44                 i++;
  45             }
  46         }
  47         return pairs;
  48         // TODO: what if there is long time between response and reply packet? Should we add a threshold and exclude those cases?
  49     }
  50
  51 }