Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/detection/SignatureDetector.java

   1 package edu.uci.iotproject.detection;
   2
   3 import edu.uci.iotproject.analysis.TriggerTrafficExtractor;
   4 import edu.uci.iotproject.analysis.UserAction;
   5 import edu.uci.iotproject.io.PcapHandleReader;
   6 import edu.uci.iotproject.util.PrintUtils;
   7 import org.jgrapht.GraphPath;
   8 import org.jgrapht.alg.shortestpath.DijkstraShortestPath;
   9 import org.jgrapht.graph.DefaultWeightedEdge;
  10 import org.jgrapht.graph.SimpleDirectedWeightedGraph;
  11 import org.pcap4j.core.*;
  12
  13 import java.time.Duration;
  14 import java.time.Instant;
  15 import java.time.ZoneId;
  16 import java.time.format.DateTimeFormatter;
  17 import java.time.format.FormatStyle;
  18 import java.util.*;
  19 import java.util.function.Consumer;
  20
  21 /**
  22  * Detects an event signature that spans one or multiple TCP connections.
  23  *
  24  * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
  25  * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
  26  */
  27 public class SignatureDetector implements PacketListener, ClusterMatcher.ClusterMatchObserver {
  28
  29     // Test client
  30     public static void main(String[] args) throws PcapNativeException, NotOpenException {
  31         String path = "/scratch/July-2018"; // Rahmadi
  32         //String path = "/Users/varmarken/temp/UCI IoT Project/experiments"; // Janus
  33
  34         // No activity test
  35         //final String inputPcapFile = path + "/evaluation/no-activity/no-activity.wlan1.pcap";
  36
  37         // D-Link Siren experiment
  38 //        final String inputPcapFile = path + "/evaluation/dlink-siren/dlink-siren.data.wlan1.pcap";
  39 //        final String inputPcapFile = path + "/evaluation/dlink-siren/dlink-siren.eth0.local.pcap";
  40         // D-Link Siren DEVICE signatures
  41 //        final String onSignatureFile = path + "/2018-08/dlink-siren/onSignature-DLink-Siren-device.sig";
  42 //        final String offSignatureFile = path + "/2018-08/dlink-siren/offSignature-DLink-Siren-device.sig";
  43         // D-Link Siren PHONE signatures
  44 //        final String onSignatureFile = path + "/2018-08/dlink-siren/onSignature-DLink-Siren-phone.sig";
  45 //        final String offSignatureFile = path + "/2018-08/dlink-siren/offSignature-DLink-Siren-phone.sig";
  46
  47         /*
  48         // Kwikset Doorlock Sep 12 experiment
  49 //        final String inputPcapFile = path + "/evaluation/kwikset-doorlock/kwikset-doorlock.data.wlan1.pcap";
  50         final String inputPcapFile = path + "/evaluation/kwikset-doorlock/kwikset-doorlock.data.eth0.pcap";
  51 //        // Kwikset Doorlock PHONE signatures
  52         final String onSignatureFile = path + "/2018-08/kwikset-doorlock/onSignature-Kwikset-Doorlock-phone-new.sig";
  53         final String offSignatureFile = path + "/2018-08/kwikset-doorlock/offSignature-Kwikset-Doorlock-phone-new.sig";
  54         */
  55
  56         // D-Link Plug experiment
  57         //final String inputPcapFile = path + "/evaluation/dlink/dlink-plug.data.wlan1.pcap";
  58 //        final String inputPcapFile = path + "/evaluation/dlink/dlink-plug.data.eth0.pcap";
  59
  60         // D-Link Plug DEVICE signatures
  61 //        final String onSignatureFile = path + "/2018-07/dlink/onSignature-DLink-Plug-device.sig";
  62 //        final String offSignatureFile = path + "/2018-07/dlink/offSignature-DLink-Plug-device.sig";
  63         // D-Link Plug PHONE signatures
  64 //        final String onSignatureFile = path + "/2018-07/dlink/onSignature-DLink-Plug-phone.sig";
  65 //        final String offSignatureFile = path + "/2018-07/dlink/offSignature-DLink-Plug-phone.sig";
  66
  67
  68         // TODO: The following are tests for signatures against training data
  69
  70         /*
  71         // D-Link Plug experiment
  72         final String inputPcapFile = path + "/training/dlink-plug/wlan1/dlink-plug.wlan1.local.pcap";
  73         // D-Link Plug DEVICE signatures
  74         //final String onSignatureFile = path + "/training/dlink-plug/signatures/dlink-plug-onSignature-device-side.sig";
  75         //final String offSignatureFile = path + "/training/dlink-plug/signatures/dlink-plug-offSignature-device-side.sig";
  76         // D-Link Plug PHONE signatures
  77         final String onSignatureFile = path + "/training/dlink-plug/signatures/dlink-plug-onSignature-phone-side.sig";
  78         final String offSignatureFile = path + "/training/dlink-plug/signatures/dlink-plug-offSignature-phone-side.sig";
  79         */
  80
  81         /*
  82         // TP-Link Plug experiment
  83         final String inputPcapFile = path + "/training/tplink-plug/wlan1/tplink-plug.wlan1.local.pcap";
  84         // TP-Link Plug DEVICE signatures
  85         //final String onSignatureFile = path + "/training/tplink-plug/signatures/tplink-plug-onSignature-device-side.sig";
  86         //final String offSignatureFile = path + "/training/tplink-plug/signatures/tplink-plug-offSignature-device-side.sig";
  87         */
  88
  89         // Arlo camera experiment
  90 //        final String inputPcapFile = path + "/training/arlo-camera/wlan1/arlo-camera.wlan1.local.pcap";
  91 //        // TP-Link Plug DEVICE signatures
  92 //        final String onSignatureFile = path + "/training/arlo-camera/signatures/arlo-camera-onSignature-phone-side.sig";
  93 //        final String offSignatureFile = path + "/training/arlo-camera/signatures/arlo-camera-offSignature-phone-side.sig";
  94
  95         // Amazon Alexa experiment
  96 //        final String inputPcapFile = path + "/training/amazon-alexa/wlan1/alexa2.wlan1.local.pcap";
  97 //        // TP-Link Plug DEVICE signatures
  98 //        final String onSignatureFile = path + "/training/amazon-alexa/signatures/amazon-alexa-onSignature-device-side.sig";
  99 //        final String offSignatureFile = path + "/training/amazon-alexa/signatures/amazon-alexa-offSignature-device-side.sig";
 100
 101         // SmartThings Plug experiment
 102 //        final String inputPcapFile = path + "/training/st-plug/wlan1/st-plug.wlan1.local.pcap";
 103         // TP-Link Plug DEVICE signatures
 104         //final String onSignatureFile = path + "/training/st-plug/signatures/st-plug-onSignature-device-side.sig";
 105         //final String offSignatureFile = path + "/training/st-plug/signatures/st-plug-offSignature-device-side.sig";
 106         // TP-Link Plug PHONE signatures
 107 //        final String onSignatureFile = path + "/training/st-plug/signatures/st-plug-onSignature-phone-side.sig";
 108 //        final String offSignatureFile = path + "/training/st-plug/signatures/st-plug-offSignature-phone-side.sig";
 109
 110
 111         // LiFX Bulb experiment
 112 //        final String inputPcapFile = path + "/training/lifx-bulb/wlan1/lifx-bulb.wlan1.local.pcap";
 113 //        // LiFX Bulb DEVICE signatures
 114 //        final String onSignatureFile = path + "/training/lifx-bulb/signatures/lifx-bulb-onSignature-device-side.sig";
 115 //        final String offSignatureFile = path + "/training/lifx-bulb/signatures/lifx-bulb-offSignature-device-side.sig";
 116         // LiFX Bulb PHONE signatures
 117 //        final String onSignatureFile = path + "/training/lifx-bulb/signatures/lifx-bulb-onSignature-phone-side.sig";
 118 //        final String offSignatureFile = path + "/training/lifx-bulb/signatures/lifx-bulb-offSignature-phone-side.sig";
 119
 120
 121         /*
 122         // Blossom Sprinkler experiment
 123         //final String inputPcapFile = path + "/training/blossom-sprinkler/wlan1/blossom-sprinkler.wlan1.local.pcap";
 124         final String inputPcapFile = path + "/training/blossom-sprinkler/eth0/blossom-sprinkler.eth0.local.pcap";
 125         // Blossom Sprinkler DEVICE signatures
 126         final String onSignatureFile = path + "/training/blossom-sprinkler/signatures/blossom-sprinkler-onSignature-device-side.sig";
 127         final String offSignatureFile = path + "/training/blossom-sprinkler/signatures/blossom-sprinkler-offSignature-device-side.sig";
 128         */
 129
 130         // Nest Thermostat experiment
 131         final String inputPcapFile = path + "/training/nest-thermostat/wlan1/nest-thermostat.wlan1.local.pcap";
 132         // Nest Thermostat DEVICE signatures
 133 //        final String onSignatureFile = path + "/training/nest-thermostat/signatures/nest-thermostat-onSignature-device-side.sig";
 134 //        final String offSignatureFile = path + "/training/nest-thermostat/signatures/nest-thermostat-offSignature-device-side.sig";
 135         // Nest Thermostat PHONE signatures
 136         final String onSignatureFile = path + "/training/nest-thermostat/signatures/nest-thermostat-onSignature-phone-side.sig";
 137         final String offSignatureFile = path + "/training/nest-thermostat/signatures/nest-thermostat-offSignature-phone-side.sig";
 138
 139         /*
 140         // Hue Bulb experiment
 141         final String inputPcapFile = path + "/training/hue-bulb/wlan1/hue-bulb.wlan1.local.pcap";
 142         // Hue Bulb PHONE signatures
 143         final String onSignatureFile = path + "/training/hue-bulb/signatures/hue-bulb-onSignature-phone-side.sig";
 144         final String offSignatureFile = path + "/training/hue-bulb/signatures/hue-bulb-offSignature-phone-side.sig";
 145         */
 146
 147         /*
 148         // TP-Link Bulb experiment
 149         final String inputPcapFile = path + "/training/tplink-bulb/wlan1/tplink-bulb.wlan1.local.pcap";
 150         // TP-Link Bulb PHONE signatures
 151         final String onSignatureFile = path + "/training/tplink-bulb/signatures/tplink-bulb-onSignature-phone-side.sig";
 152         final String offSignatureFile = path + "/training/tplink-bulb/signatures/tplink-bulb-offSignature-phone-side.sig";
 153         */
 154
 155         /*
 156         // WeMo Plug experiment
 157         final String inputPcapFile = path + "/training/wemo-plug/wlan1/wemo-plug.wlan1.local.pcap";
 158         // WeMo Plug PHONE signatures
 159         final String onSignatureFile = path + "/training/wemo-plug/signatures/wemo-plug-onSignature-device-side.sig";
 160         final String offSignatureFile = path + "/training/wemo-plug/signatures/wemo-plug-offSignature-device-side.sig";
 161         */
 162
 163         /*
 164         // WeMo Insight Plug experiment
 165         final String inputPcapFile = path + "/training/wemo-insight-plug/wlan1/wemo-insight-plug.wlan1.local.pcap";
 166         // WeMo Insight Plug PHONE signatures
 167         final String onSignatureFile = path + "/training/wemo-insight-plug/signatures/wemo-insight-plug-onSignature-device-side.sig";
 168         final String offSignatureFile = path + "/training/wemo-insight-plug/signatures/wemo-insight-plug-offSignature-device-side.sig";
 169         */
 170
 171
 172         // Kwikset Doorlock Sep 12 experiment
 173 //        final String inputPcapFile = path + "/2018-08/kwikset-doorlock/kwikset3.wlan1.local.pcap";
 174 //        // Kwikset Doorlock PHONE signatures
 175 //        final String onSignatureFile = path + "/2018-08/kwikset-doorlock/onSignature-Kwikset-Doorlock-phone.sig";
 176 //        final String offSignatureFile = path + "/2018-08/kwikset-doorlock/offSignature-Kwikset-Doorlock-phone.sig";
 177
 178
 179         /*
 180         // D-Link Siren experiment
 181         final String inputPcapFile = path + "/2018-08/dlink-siren/dlink-siren.wlan1.local.pcap";
 182         // D-Link Siren DEVICE signatures
 183         //final String onSignatureFile = path + "/2018-08/dlink-siren/onSignature-DLink-Siren-device.sig";
 184         //final String offSignatureFile = path + "/2018-08/dlink-siren/offSignature-DLink-Siren-device.sig";
 185         // D-Link Siren PHONE signatures
 186         final String onSignatureFile = path + "/2018-08/dlink-siren/onSignature-DLink-Siren-phone.sig";
 187         final String offSignatureFile = path + "/2018-08/dlink-siren/offSignature-DLink-Siren-phone.sig";
 188         */
 189
 190         List<List<List<PcapPacket>>> onSignature = PrintUtils.deserializeSignatureFromFile(onSignatureFile);
 191         List<List<List<PcapPacket>>> offSignature = PrintUtils.deserializeSignatureFromFile(offSignatureFile);
 192
 193         // LAN
 194         SignatureDetector onDetector = new SignatureDetector(onSignature, null);
 195         SignatureDetector offDetector = new SignatureDetector(offSignature, null);
 196         // WAN
 197 //        SignatureDetector onDetector = new SignatureDetector(onSignature, "128.195.205.105");
 198 //        SignatureDetector offDetector = new SignatureDetector(offSignature, "128.195.205.105");
 199
 200         final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM).
 201                 withLocale(Locale.US).withZone(ZoneId.of("America/Los_Angeles"));
 202
 203         // Outputs information about a detected event to std.out
 204         final Consumer<UserAction> outputter = ua -> {
 205             String eventDescription;
 206             switch (ua.getType()) {
 207                 case TOGGLE_ON:
 208                     eventDescription = "ON";
 209                     break;
 210                 case TOGGLE_OFF:
 211                     eventDescription = "OFF";
 212                     break;
 213                 default:
 214                     throw new AssertionError("unhandled event type");
 215             }
 216             //String output = String.format("[ !!! %s SIGNATURE DETECTED at %s !!! ]",
 217             //      eventDescription, dateTimeFormatter.format(ua.getTimestamp()));
 218             String output = String.format("%s",
 219                     dateTimeFormatter.format(ua.getTimestamp()));
 220             System.out.println(output);
 221         };
 222
 223         // Let's create observers that construct a UserAction representing the detected event.
 224         final List<UserAction> detectedEvents = new ArrayList<>();
 225         onDetector.addObserver((searched, match) -> {
 226             PcapPacket firstPkt = match.get(0).get(0);
 227             detectedEvents.add(new UserAction(UserAction.Type.TOGGLE_ON, firstPkt.getTimestamp()));
 228         });
 229         offDetector.addObserver((searched, match) -> {
 230             PcapPacket firstPkt = match.get(0).get(0);
 231             detectedEvents.add(new UserAction(UserAction.Type.TOGGLE_OFF, firstPkt.getTimestamp()));
 232         });
 233
 234         PcapHandle handle;
 235         try {
 236             handle = Pcaps.openOffline(inputPcapFile, PcapHandle.TimestampPrecision.NANO);
 237         } catch (PcapNativeException pne) {
 238             handle = Pcaps.openOffline(inputPcapFile);
 239         }
 240         PcapHandleReader reader = new PcapHandleReader(handle, p -> true, onDetector, offDetector);
 241         reader.readFromHandle();
 242
 243         // TODO: need a better way of triggering detection than this...
 244         onDetector.mClusterMatchers.forEach(cm -> cm.performDetection());
 245         offDetector.mClusterMatchers.forEach(cm -> cm.performDetection());
 246
 247         // Sort the list of detected events by timestamp to make it easier to compare it line-by-line with the trigger
 248         // times file.
 249         Collections.sort(detectedEvents, Comparator.comparing(UserAction::getTimestamp));
 250
 251
 252         // Output the detected events
 253         //detectedEvents.forEach(outputter);
 254
 255         // TODO: Temporary clean up until we clean the pipeline
 256         List<UserAction> cleanedDetectedEvents = SignatureDetector.removeDuplicates(detectedEvents);
 257         cleanedDetectedEvents.forEach(outputter);
 258     }
 259
 260     /**
 261      * The signature that this {@link SignatureDetector} is searching for.
 262      */
 263     private final List<List<List<PcapPacket>>> mSignature;
 264
 265     /**
 266      * The {@link ClusterMatcher}s in charge of detecting each individual sequence of packets that together make up the
 267      * the signature.
 268      */
 269     private final List<ClusterMatcher> mClusterMatchers;
 270
 271     /**
 272      * For each {@code i} ({@code i >= 0 && i < pendingMatches.length}), {@code pendingMatches[i]} holds the matches
 273      * found by the {@link ClusterMatcher} at {@code mClusterMatchers.get(i)} that have yet to be "consumed", i.e.,
 274      * have yet to be included in a signature detected by this {@link SignatureDetector} (a signature can be encompassed
 275      * of multiple packet sequences occurring shortly after one another on multiple connections).
 276      */
 277     private final List<List<PcapPacket>>[] pendingMatches;
 278
 279     /**
 280      * Maps a {@link ClusterMatcher} to its corresponding index in {@link #pendingMatches}.
 281      */
 282     private final Map<ClusterMatcher, Integer> mClusterMatcherIds;
 283
 284     private final List<SignatureDetectionObserver> mObservers = new ArrayList<>();
 285
 286     /**
 287      * Remove duplicates in {@code List} of {@code UserAction} objects. We need to clean this up for user actions
 288      * that appear multiple times.
 289      * TODO: This static method is probably just for temporary and we could get rid of this after we clean up
 290      * TODO:    the pipeline
 291      *
 292      * @param listUserAction A {@link List} of {@code UserAction}.
 293      *
 294      */
 295     public static List<UserAction> removeDuplicates(List<UserAction> listUserAction) {
 296
 297         // Iterate and check for duplicates (check timestamps)
 298         Set<Long> epochSecondSet = new HashSet<>();
 299         // Create a target list for cleaned up list
 300         List<UserAction> listUserActionClean = new ArrayList<>();
 301         for(UserAction userAction : listUserAction) {
 302             // Don't insert if any duplicate is found
 303             if(!epochSecondSet.contains(userAction.getTimestamp().getEpochSecond())) {
 304                 listUserActionClean.add(userAction);
 305                 epochSecondSet.add(userAction.getTimestamp().getEpochSecond());
 306             }
 307         }
 308         return listUserActionClean;
 309     }
 310
 311     public SignatureDetector(List<List<List<PcapPacket>>> searchedSignature, String routerWanIp) {
 312         // note: doesn't protect inner lists from changes :'(
 313         mSignature = Collections.unmodifiableList(searchedSignature);
 314         // Generate corresponding/appropriate ClusterMatchers based on the provided signature
 315         List<ClusterMatcher> clusterMatchers = new ArrayList<>();
 316         for (List<List<PcapPacket>> cluster : mSignature) {
 317             clusterMatchers.add(new ClusterMatcher(cluster, routerWanIp, this));
 318         }
 319         mClusterMatchers = Collections.unmodifiableList(clusterMatchers);
 320
 321         // < exploratory >
 322         pendingMatches = new List[mClusterMatchers.size()];
 323         for (int i = 0; i < pendingMatches.length; i++) {
 324             pendingMatches[i] = new ArrayList<>();
 325         }
 326         Map<ClusterMatcher, Integer> clusterMatcherIds = new HashMap<>();
 327         for (int i = 0; i < mClusterMatchers.size(); i++) {
 328             clusterMatcherIds.put(mClusterMatchers.get(i), i);
 329         }
 330         mClusterMatcherIds = Collections.unmodifiableMap(clusterMatcherIds);
 331     }
 332
 333     public void addObserver(SignatureDetectionObserver observer) {
 334         mObservers.add(observer);
 335     }
 336
 337     public boolean removeObserver(SignatureDetectionObserver observer) {
 338         return mObservers.remove(observer);
 339     }
 340
 341     @Override
 342     public void gotPacket(PcapPacket packet) {
 343         // simply delegate packet reception to all ClusterMatchers.
 344         mClusterMatchers.forEach(cm -> cm.gotPacket(packet));
 345     }
 346
 347     @Override
 348     public void onMatch(ClusterMatcher clusterMatcher, List<PcapPacket> match) {
 349         // Add the match at the corresponding index
 350         pendingMatches[mClusterMatcherIds.get(clusterMatcher)].add(match);
 351         checkSignatureMatch();
 352     }
 353
 354     private void checkSignatureMatch() {
 355         // << Graph-based approach using Balint's idea. >>
 356         // This implementation assumes that the packets in the inner lists (the sequences) are ordered by asc timestamp.
 357
 358         // There cannot be a signature match until each ClusterMatcher has found a match of its respective sequence.
 359         if (Arrays.stream(pendingMatches).noneMatch(l -> l.isEmpty())) {
 360             // Construct the DAG
 361             final SimpleDirectedWeightedGraph<Vertex, DefaultWeightedEdge> graph =
 362                     new SimpleDirectedWeightedGraph<>(DefaultWeightedEdge.class);
 363             // Add a vertex for each match found by all ClusterMatchers
 364             // And maintain an array to keep track of what cluster matcher each vertex corresponds to
 365             final List<Vertex>[] vertices = new List[pendingMatches.length];
 366             for (int i = 0; i < pendingMatches.length; i++) {
 367                 vertices[i] = new ArrayList<>();
 368                 for (List<PcapPacket> sequence : pendingMatches[i]) {
 369                     Vertex v = new Vertex(sequence);
 370                     vertices[i].add(v); // retain reference for later when we are to add edges
 371                     graph.addVertex(v); // add to vertex to graph
 372                 }
 373             }
 374             // Add dummy source and sink vertices to facilitate search.
 375             final Vertex source = new Vertex(null);
 376             final Vertex sink = new Vertex(null);
 377             graph.addVertex(source);
 378             graph.addVertex(sink);
 379             // The source is connected to all vertices that wrap the sequences detected by ClusterMatcher at index 0.
 380             // Note: zero cost edges as this is just a dummy link to facilitate search from a common start node.
 381             for (Vertex v : vertices[0]) {
 382                 DefaultWeightedEdge edge = graph.addEdge(source, v);
 383                 graph.setEdgeWeight(edge, 0.0);
 384             }
 385             // Similarly, all vertices that wrap the sequences detected by the last ClusterMatcher of the signature
 386             // are connected to the sink node.
 387             for (Vertex v : vertices[vertices.length-1]) {
 388                 DefaultWeightedEdge edge = graph.addEdge(v, sink);
 389                 graph.setEdgeWeight(edge, 0.0);
 390             }
 391             // Now link sequences detected by ClusterMatcher at index i to sequences detected by ClusterMatcher at index
 392             // i+1 if they obey the timestamp constraint (i.e., that the latter is later in time than the former).
 393             for (int i = 0; i < vertices.length; i++) {
 394                 int j = i + 1;
 395                 if (j < vertices.length) {
 396                     for (Vertex iv : vertices[i]) {
 397                         PcapPacket ivLast = iv.sequence.get(iv.sequence.size()-1);
 398                         for (Vertex jv : vertices[j]) {
 399                             PcapPacket jvFirst = jv.sequence.get(jv.sequence.size()-1);
 400                             if (ivLast.getTimestamp().isBefore(jvFirst.getTimestamp())) {
 401                                 DefaultWeightedEdge edge = graph.addEdge(iv, jv);
 402                                 // The weight is the duration of the i'th sequence plus the duration between the i'th
 403                                 // and i+1'th sequence.
 404                                 Duration d = Duration.
 405                                         between(iv.sequence.get(0).getTimestamp(), jvFirst.getTimestamp());
 406                                 // Unfortunately weights are double values, so must convert from long to double.
 407                                 // TODO: need nano second precision? If so, use d.toNanos().
 408                                 // TODO: risk of overflow when converting from long to double..?
 409                                 graph.setEdgeWeight(edge, Long.valueOf(d.toMillis()).doubleValue());
 410                             }
 411                             // Alternative version if we cannot assume that sequences are ordered by timestamp:
 412 //                            if (iv.sequence.stream().max(Comparator.comparing(PcapPacket::getTimestamp)).get()
 413 //                                    .getTimestamp().isBefore(jv.sequence.stream().min(
 414 //                                            Comparator.comparing(PcapPacket::getTimestamp)).get().getTimestamp())) {
 415 //
 416 //                            }
 417                         }
 418                     }
 419                 }
 420             }
 421             // Graph construction complete, run shortest-path to find a (potential) signature match.
 422             DijkstraShortestPath<Vertex, DefaultWeightedEdge> dijkstra = new DijkstraShortestPath<>(graph);
 423             GraphPath<Vertex, DefaultWeightedEdge> shortestPath = dijkstra.getPath(source, sink);
 424             if (shortestPath != null) {
 425                 // The total weight is the duration between the first packet of the first sequence and the last packet
 426                 // of the last sequence, so we simply have to compare the weight against the timeframe that we allow
 427                 // the signature to span. For now we just use the inclusion window we defined for training purposes.
 428                 // Note however, that we must convert back from double to long as the weight is stored as a double in
 429                 // JGraphT's API.
 430                 if (((long)shortestPath.getWeight()) < TriggerTrafficExtractor.INCLUSION_WINDOW_MILLIS) {
 431                     // There's a signature match!
 432                     // Extract the match from the vertices
 433                     List<List<PcapPacket>> signatureMatch = new ArrayList<>();
 434                     for(Vertex v : shortestPath.getVertexList()) {
 435                         if (v == source || v == sink) {
 436                             // Skip the dummy source and sink nodes.
 437                             continue;
 438                         }
 439                         signatureMatch.add(v.sequence);
 440                         // As there is a one-to-one correspondence between vertices[] and pendingMatches[], we know that
 441                         // the sequence we've "consumed" for index i of the matched signature is also at index i in
 442                         // pendingMatches. We must remove it from pendingMatches so that we don't use it to construct
 443                         // another signature match in a later call.
 444                         pendingMatches[signatureMatch.size()-1].remove(v.sequence);
 445                     }
 446                     // Declare success: notify observers
 447                     mObservers.forEach(obs -> obs.onSignatureDetected(mSignature,
 448                             Collections.unmodifiableList(signatureMatch)));
 449                 }
 450             }
 451         }
 452     }
 453
 454     /**
 455      * Used for registering for notifications of signatures detected by a {@link SignatureDetector}.
 456      */
 457     interface SignatureDetectionObserver {
 458
 459         /**
 460          * Invoked when the {@link SignatureDetector} detects the presence of a signature in the traffic that it's
 461          * examining.
 462          * @param searchedSignature The signature that the {@link SignatureDetector} reporting the match is searching
 463          *                          for.
 464          * @param matchingTraffic The actual traffic trace that matches the searched signature.
 465          */
 466         void onSignatureDetected(List<List<List<PcapPacket>>> searchedSignature,
 467                                  List<List<PcapPacket>> matchingTraffic);
 468     }
 469
 470     /**
 471      * Encapsulates a {@code List<PcapPacket>} so as to allow the list to be used as a vertex in a graph while avoiding
 472      * the expensive {@link AbstractList#equals(Object)} calls when adding vertices to the graph.
 473      * Using this wrapper makes the incurred {@code equals(Object)} calls delegate to {@link Object#equals(Object)}
 474      * instead of {@link AbstractList#equals(Object)}. The net effect is a faster implementation, but the graph will not
 475      * recognize two lists that contain the same items--from a value and not reference point of view--as the same
 476      * vertex. However, this is fine for our purposes -- in fact restricting it to reference equality seems more
 477      * appropriate.
 478      */
 479     private static class Vertex {
 480         private final List<PcapPacket> sequence;
 481         private Vertex(List<PcapPacket> wrappedSequence) {
 482             sequence = wrappedSequence;
 483         }
 484     }
 485 }