1 package edu.uci.iotproject.detection.layer2;
3 import edu.uci.iotproject.analysis.TriggerTrafficExtractor;
4 import edu.uci.iotproject.analysis.UserAction;
5 import edu.uci.iotproject.detection.AbstractClusterMatcher;
6 import edu.uci.iotproject.detection.ClusterMatcherObserver;
7 import edu.uci.iotproject.detection.SignatureDetectorObserver;
8 import edu.uci.iotproject.io.PcapHandleReader;
9 import edu.uci.iotproject.io.PrintWriterUtils;
10 import edu.uci.iotproject.trafficreassembly.layer2.Layer2Flow;
11 import edu.uci.iotproject.trafficreassembly.layer2.Layer2FlowReassembler;
12 import edu.uci.iotproject.util.PcapPacketUtils;
13 import edu.uci.iotproject.util.PrintUtils;
14 import org.jgrapht.GraphPath;
15 import org.jgrapht.alg.shortestpath.DijkstraShortestPath;
16 import org.jgrapht.graph.DefaultWeightedEdge;
17 import org.jgrapht.graph.SimpleDirectedWeightedGraph;
18 import org.pcap4j.core.*;
21 import java.io.FileWriter;
22 import java.io.IOException;
23 import java.io.PrintWriter;
24 import java.time.Duration;
26 import java.util.function.Function;
27 import java.util.regex.Pattern;
30 * Performs layer 2 signature detection.
32 * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
33 * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
35 public class Layer2SignatureDetector implements PacketListener, ClusterMatcherObserver {
38 * If set to {@code true}, output written to the results file is also dumped to standard out.
40 private static boolean DUPLICATE_OUTPUT_TO_STD_OUT = true;
44 * This is only useful for the filter for direction when it is a WAN signature (Phone-Cloud or Device-Cloud).
45 * Phone-Device signatures do not have router MAC address in it.
47 // TODO: We can remove the following constants if we do remove router's MAC filtering for directions
48 private static String TRAINING_ROUTER_WLAN_MAC = null;
49 private static String ROUTER_WLAN_MAC = null;
50 //private static String TRAINING_ROUTER_WLAN_MAC = "b0:b9:8a:73:69:8e";
51 //private static String ROUTER_WLAN_MAC = "00:c1:b1:14:eb:31";
53 private static List<Function<Layer2Flow, Boolean>> parseSignatureMacFilters(String filtersString) {
54 List<Function<Layer2Flow, Boolean>> filters = new ArrayList<>();
55 String[] filterRegexes = filtersString.split(";");
56 for (String filterRegex : filterRegexes) {
57 final Pattern regex = Pattern.compile(filterRegex);
58 // Create a filter that includes all flows where one of the two MAC addresses match the regex.
59 filters.add(flow -> regex.matcher(flow.getEndpoint1().toString()).matches() || regex.matcher(flow.getEndpoint2().toString()).matches());
64 public static void main(String[] args) throws PcapNativeException, NotOpenException, IOException {
65 String errMsg = String.format("SPECTO version 1.0\n" +
66 "Copyright (C) 2018-2019 Janus Varmarken and Rahmadi Trimananda.\n" +
67 "University of California, Irvine.\n" +
68 "All rights reserved.\n\n" +
69 "Usage: %s inputPcapFile onAnalysisFile offAnalysisFile onSignatureFile offSignatureFile " +
70 "resultsFile signatureDuration eps onMaxSkippedPackets offMaxSkippedPackets" +
71 "\n inputPcapFile: the target of the detection" +
72 "\n onAnalysisFile: the file that contains the ON clusters analysis" +
73 "\n offAnalysisFile: the file that contains the OFF clusters analysis" +
74 "\n onSignatureFile: the file that contains the ON signature to search for" +
75 "\n offSignatureFile: the file that contains the OFF signature to search for" +
76 "\n resultsFile: where to write the results of the detection" +
77 "\n signatureDuration: the maximum duration of signature detection" +
78 "\n epsilon: the epsilon value for the DBSCAN algorithm\n" +
79 "\n Additional options (add '-r' before the following two parameters):" +
80 "\n delta: delta for relaxed matching" +
81 "\n packetId: packet number in the sequence" +
82 "\n (could be more than one packet whose matching is relaxed, " +
83 "\n e.g., 0,1 for packets 0 and 1)",
84 Layer2SignatureDetector.class.getSimpleName());
85 String optParamsExplained = "Above are the required, positional arguments. In addition to these, the " +
86 "following options and associated positional arguments may be used:\n" +
87 " '-onmacfilters <regex>;<regex>;...;<regex>' which specifies that sequence matching should ONLY" +
88 " be performed on flows where the MAC of one of the two endpoints matches the given regex. Note " +
89 "that you MUST specify a regex for each cluster of the signature. This is to facilitate more " +
90 "aggressive filtering on parts of the signature (e.g., the communication that involves the " +
91 "smart home device itself as one can drop all flows that do not include an endpoint with a MAC " +
92 "that matches the vendor's prefix).\n" +
93 " '-offmacfilters <regex>;<regex>;...;<regex>' works exactly the same as onmacfilters, but " +
94 "applies to the OFF signature instead of the ON signature.\n" +
95 " '-sout <boolean literal>' true/false literal indicating if output should also be printed to std out; default is true.\n" +
96 " '-vpn <router mac>' router's MAC address; this is to simulate a VPN that combines all flows even when the traffic is not a VPN traffic.\n" +
97 " '-onskipped <max duration of on-signature>' the maximum duration of ON signature detection.\n" +
98 " '-offskipped <max duration of off-signature>' the maximum duration of OFF signature detection.\n";
99 // Parse required parameters.
100 if (args.length < 8) {
101 System.out.println(errMsg);
102 System.out.println(optParamsExplained);
105 final String pcapFile = args[0];
106 final String onClusterAnalysisFile = args[1];
107 final String offClusterAnalysisFile = args[2];
108 final String onSignatureFile = args[3];
109 final String offSignatureFile = args[4];
110 final String resultsFile = args[5];
111 final int signatureDuration = Integer.parseInt(args[6]);
112 final double eps = Double.parseDouble(args[7]);
113 // Additional feature---relaxed matching
115 final Set<Integer> packetSet = new HashSet<>();
116 if (args.length > 8 && args[8].equals("-r")) {
117 delta = Integer.parseInt(args[9]);
118 StringTokenizer stringTokenizerOff = new StringTokenizer(args[10], ",");
119 // Add the list of packet IDs
120 while(stringTokenizerOff.hasMoreTokens()) {
121 int id = Integer.parseInt(stringTokenizerOff.nextToken());
125 // Parse optional parameters.
126 List<Function<Layer2Flow, Boolean>> onSignatureMacFilters = null, offSignatureMacFilters = null;
127 String vpnClientMacAddress = null;
128 int onMaxSkippedPackets = -1;
129 int offMaxSkippedPackets = -1;
130 final int optParamsStartIdx = 8;
131 if (args.length > optParamsStartIdx) {
132 for (int i = optParamsStartIdx; i < args.length; i++) {
133 if (args[i].equalsIgnoreCase("-onMacFilters")) {
134 // Next argument is the cluster-wise MAC filters (separated by semicolons).
135 onSignatureMacFilters = parseSignatureMacFilters(args[i+1]);
136 } else if (args[i].equalsIgnoreCase("-offMacFilters")) {
137 // Next argument is the cluster-wise MAC filters (separated by semicolons).
138 offSignatureMacFilters = parseSignatureMacFilters(args[i+1]);
139 } else if (args[i].equalsIgnoreCase("-sout")) {
140 // Next argument is a boolean true/false literal.
141 DUPLICATE_OUTPUT_TO_STD_OUT = Boolean.parseBoolean(args[i+1]);
142 } else if (args[i].equalsIgnoreCase("-vpn")) {
143 vpnClientMacAddress = args[i+1];
144 } else if (args[i].equalsIgnoreCase("-onskipped")) {
145 if (i+2 > args.length - 1 || !args[i+2].equalsIgnoreCase("-offskipped")) {
146 throw new Error("Please make sure that the -onskipped and -offskipped options are both used at the same time...");
148 if (args[i+2].equalsIgnoreCase("-offskipped")) {
149 onMaxSkippedPackets = Integer.parseInt(args[i+1]);
150 offMaxSkippedPackets = Integer.parseInt(args[i+3]);
156 // Prepare file outputter.
157 File outputFile = new File(resultsFile);
158 outputFile.getParentFile().mkdirs();
159 final PrintWriter resultsWriter = new PrintWriter(new FileWriter(outputFile));
160 // Include metadata as comments at the top
161 PrintWriterUtils.println("# Detection results for:", resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
162 PrintWriterUtils.println("# - inputPcapFile: " + pcapFile, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
163 PrintWriterUtils.println("# - onAnalysisFile: " + onClusterAnalysisFile, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
164 PrintWriterUtils.println("# - offAnalysisFile: " + offClusterAnalysisFile, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
165 PrintWriterUtils.println("# - onSignatureFile: " + onSignatureFile, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
166 PrintWriterUtils.println("# - offSignatureFile: " + offSignatureFile, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
167 resultsWriter.flush();
169 // Create signature detectors and add observers that output their detected events.
170 List<List<List<PcapPacket>>> onSignature = PrintUtils.deserializeFromFile(onSignatureFile);
171 List<List<List<PcapPacket>>> offSignature = PrintUtils.deserializeFromFile(offSignatureFile);
172 // Load signature analyses
173 List<List<List<PcapPacket>>> onClusterAnalysis = PrintUtils.deserializeFromFile(onClusterAnalysisFile);
174 List<List<List<PcapPacket>>> offClusterAnalysis = PrintUtils.deserializeFromFile(offClusterAnalysisFile);
175 // TODO: FOR NOW WE DECIDE PER SIGNATURE AND THEN WE OR THE BOOLEANS
176 // TODO: SINCE WE ONLY HAVE 2 SIGNATURES FOR NOW (ON AND OFF), THEN IT IS USUALLY EITHER RANGE-BASED OR
177 // TODO: STRICT MATCHING
178 // Check if we should use range-based matching
179 boolean isRangeBasedForOn = PcapPacketUtils.isRangeBasedMatching(onSignature, eps, offSignature);
180 boolean isRangeBasedForOff = PcapPacketUtils.isRangeBasedMatching(offSignature, eps, onSignature);
181 // TODO: WE DON'T DO RANGE-BASED FOR NOW BECAUSE THE RESULTS ARE TERRIBLE FOR LAYER 2 MATCHING
182 // TODO: THIS WOULD ONLY WORK FOR SIGNATURES LONGER THAN 2 PACKETS
183 // boolean isRangeBasedForOn = false;
184 // boolean isRangeBasedForOff = false;
185 // Update the signature with ranges if it is range-based
186 if (isRangeBasedForOn) {
187 onSignature = PcapPacketUtils.useRangeBasedMatching(onSignature, onClusterAnalysis);
189 if (isRangeBasedForOff) {
190 offSignature = PcapPacketUtils.useRangeBasedMatching(offSignature, offClusterAnalysis);
192 Layer2SignatureDetector onDetector = onSignatureMacFilters == null ?
193 new Layer2SignatureDetector(onSignature, TRAINING_ROUTER_WLAN_MAC, ROUTER_WLAN_MAC, signatureDuration,
194 isRangeBasedForOn, eps, onMaxSkippedPackets, vpnClientMacAddress, delta, packetSet) :
195 new Layer2SignatureDetector(onSignature, TRAINING_ROUTER_WLAN_MAC, ROUTER_WLAN_MAC,
196 onSignatureMacFilters, signatureDuration, isRangeBasedForOn, eps, onMaxSkippedPackets,
197 vpnClientMacAddress, delta, packetSet);
198 Layer2SignatureDetector offDetector = offSignatureMacFilters == null ?
199 new Layer2SignatureDetector(offSignature, TRAINING_ROUTER_WLAN_MAC, ROUTER_WLAN_MAC, signatureDuration,
200 isRangeBasedForOff, eps, offMaxSkippedPackets, vpnClientMacAddress, delta, packetSet) :
201 new Layer2SignatureDetector(offSignature, TRAINING_ROUTER_WLAN_MAC, ROUTER_WLAN_MAC, offSignatureMacFilters,
202 signatureDuration, isRangeBasedForOff, eps, offMaxSkippedPackets, vpnClientMacAddress, delta, packetSet);
203 final List<UserAction> detectedEvents = new ArrayList<>();
204 onDetector.addObserver((signature, match) -> {
205 UserAction event = new UserAction(UserAction.Type.TOGGLE_ON, match.get(0).get(0).getTimestamp());
206 PrintWriterUtils.println(event, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
207 detectedEvents.add(event);
209 offDetector.addObserver((signature, match) -> {
210 UserAction event = new UserAction(UserAction.Type.TOGGLE_OFF, match.get(0).get(0).getTimestamp());
211 PrintWriterUtils.println(event, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
212 detectedEvents.add(event);
215 // Load the PCAP file
218 handle = Pcaps.openOffline(pcapFile, PcapHandle.TimestampPrecision.NANO);
219 } catch (PcapNativeException pne) {
220 handle = Pcaps.openOffline(pcapFile);
222 PcapHandleReader reader = new PcapHandleReader(handle, p -> true, onDetector, offDetector);
224 reader.readFromHandle();
226 String resultOn = "# Number of detected events of type " + UserAction.Type.TOGGLE_ON + ": " +
227 detectedEvents.stream().filter(ua -> ua.getType() == UserAction.Type.TOGGLE_ON).count();
228 String resultOff = "# Number of detected events of type " + UserAction.Type.TOGGLE_OFF + ": " +
229 detectedEvents.stream().filter(ua -> ua.getType() == UserAction.Type.TOGGLE_OFF).count();
230 String onMaximumSkippedPackets = "# Maximum number of skipped packets in ON signature " +
231 Integer.toString(onDetector.getMaxSkippedPackets());
232 String offMaximumSkippedPackets = "# Maximum number of skipped packets in OFF signature " +
233 Integer.toString(offDetector.getMaxSkippedPackets());
234 PrintWriterUtils.println(resultOn, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
235 PrintWriterUtils.println(resultOff, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
236 // Perform the skipped packet analysis if needed
237 if (onMaxSkippedPackets != -1 && offMaxSkippedPackets != -1) {
238 PrintWriterUtils.println(onMaximumSkippedPackets, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
239 for (Integer skippedPackets : onDetector.getSkippedPackets()) {
240 PrintWriterUtils.println(skippedPackets, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
242 PrintWriterUtils.println(offMaximumSkippedPackets, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
243 for (Integer skippedPackets : offDetector.getSkippedPackets()) {
244 PrintWriterUtils.println(skippedPackets, resultsWriter, DUPLICATE_OUTPUT_TO_STD_OUT);
247 // Flush output to results file and close it.
248 resultsWriter.flush();
249 resultsWriter.close();
253 * The signature that this {@link Layer2SignatureDetector} is searching for.
255 private final List<List<List<PcapPacket>>> mSignature;
258 * The {@link Layer2ClusterMatcher}s in charge of detecting each individual sequence of packets that together make
259 * up the the signature.
261 private final List<Layer2ClusterMatcher> mClusterMatchers;
264 * For each {@code i} ({@code i >= 0 && i < mPendingMatches.length}), {@code mPendingMatches[i]} holds the matches
265 * found by the {@link Layer2ClusterMatcher} at {@code mClusterMatchers.get(i)} that have yet to be "consumed",
266 * i.e., have yet to be included in a signature detected by this {@link Layer2SignatureDetector} (a signature can
267 * be encompassed of multiple packet sequences occurring shortly after one another on multiple connections).
269 private final List<List<PcapPacket>>[] mPendingMatches;
272 * Maps a {@link Layer2ClusterMatcher} to its corresponding index in {@link #mPendingMatches}.
274 private final Map<Layer2ClusterMatcher, Integer> mClusterMatcherIds;
277 * In charge of reassembling layer 2 packet flows.
279 private Layer2FlowReassembler mFlowReassembler;
281 private final List<SignatureDetectorObserver> mObservers = new ArrayList<>();
283 private int mInclusionTimeMillis;
286 * Skipped-packet analysis.
288 private int mMaxSkippedPackets;
289 private List<Integer> mSkippedPackets;
293 public Layer2SignatureDetector(List<List<List<PcapPacket>>> searchedSignature, String trainingRouterWlanMac,
294 String routerWlanMac, int signatureDuration, boolean isRangeBased, double eps,
295 int limitSkippedPackets, String vpnClientMacAddress, int delta, Set<Integer> packetSet) {
296 this(searchedSignature, trainingRouterWlanMac, routerWlanMac, null, signatureDuration, isRangeBased,
297 eps, limitSkippedPackets, vpnClientMacAddress, delta, packetSet);
300 public Layer2SignatureDetector(List<List<List<PcapPacket>>> searchedSignature, String trainingRouterWlanMac,
301 String routerWlanMac, List<Function<Layer2Flow, Boolean>> flowFilters,
302 int inclusionTimeMillis, boolean isRangeBased, double eps, int limitSkippedPackets,
303 String vpnClientMacAddress, int delta, Set<Integer> packetSet) {
304 if (flowFilters != null && flowFilters.size() != searchedSignature.size()) {
305 throw new IllegalArgumentException("If flow filters are used, there must be a flow filter for each cluster " +
306 "of the signature.");
308 mSignature = Collections.unmodifiableList(searchedSignature);
309 List<Layer2ClusterMatcher> clusterMatchers = new ArrayList<>();
310 for (int i = 0; i < mSignature.size(); i++) {
311 List<List<PcapPacket>> cluster = mSignature.get(i);
312 Layer2ClusterMatcher clusterMatcher = flowFilters == null ?
313 new Layer2ClusterMatcher(cluster, trainingRouterWlanMac, routerWlanMac, inclusionTimeMillis,
314 isRangeBased, eps, limitSkippedPackets, delta, packetSet) :
315 new Layer2ClusterMatcher(cluster, trainingRouterWlanMac, routerWlanMac, flowFilters.get(i),
316 inclusionTimeMillis, isRangeBased, eps, limitSkippedPackets, delta, packetSet);
317 clusterMatcher.addObserver(this);
318 clusterMatchers.add(clusterMatcher);
320 mClusterMatchers = Collections.unmodifiableList(clusterMatchers);
321 mPendingMatches = new List[mClusterMatchers.size()];
322 for (int i = 0; i < mPendingMatches.length; i++) {
323 mPendingMatches[i] = new ArrayList<>();
325 Map<Layer2ClusterMatcher, Integer> clusterMatcherIds = new HashMap<>();
326 for (int i = 0; i < mClusterMatchers.size(); i++) {
327 clusterMatcherIds.put(mClusterMatchers.get(i), i);
329 mClusterMatcherIds = Collections.unmodifiableMap(clusterMatcherIds);
330 // Register all cluster matchers to receive a notification whenever a new flow is encountered.
331 if (vpnClientMacAddress != null) {
332 mFlowReassembler = new Layer2FlowReassembler(vpnClientMacAddress);
334 mFlowReassembler = new Layer2FlowReassembler();
336 mClusterMatchers.forEach(cm -> mFlowReassembler.addObserver(cm));
337 mInclusionTimeMillis =
338 inclusionTimeMillis == 0 ? TriggerTrafficExtractor.INCLUSION_WINDOW_MILLIS : inclusionTimeMillis;
339 mMaxSkippedPackets = 0;
340 mSkippedPackets = new ArrayList<>();
343 public int getMaxSkippedPackets() {
344 return mMaxSkippedPackets;
347 public List<Integer> getSkippedPackets() {
348 for (Layer2ClusterMatcher matcher : mClusterMatchers) {
349 mSkippedPackets.addAll(matcher.getSkippedPackets());
351 return mSkippedPackets;
355 public void gotPacket(PcapPacket packet) {
356 // Forward packet processing to the flow reassembler that in turn notifies the cluster matchers as appropriate
357 mFlowReassembler.gotPacket(packet);
361 public void onMatch(AbstractClusterMatcher clusterMatcher, List<PcapPacket> match) {
362 // TODO: a cluster matcher found a match
363 if (clusterMatcher instanceof Layer2ClusterMatcher) {
364 // Add the match at the corresponding index
365 mPendingMatches[mClusterMatcherIds.get(clusterMatcher)].add(match);
366 checkSignatureMatch();
367 // Update maximum number of skipped packets
368 if (mMaxSkippedPackets < ((Layer2ClusterMatcher) clusterMatcher).getMaxSkippedPackets()) {
369 mMaxSkippedPackets = ((Layer2ClusterMatcher) clusterMatcher).getMaxSkippedPackets();
374 public void addObserver(SignatureDetectorObserver observer) {
375 mObservers.add(observer);
378 public boolean removeObserver(SignatureDetectorObserver observer) {
379 return mObservers.remove(observer);
383 @SuppressWarnings("Duplicates")
384 private void checkSignatureMatch() {
385 // << Graph-based approach using Balint's idea. >>
386 // This implementation assumes that the packets in the inner lists (the sequences) are ordered by asc timestamp.
388 // There cannot be a signature match until each Layer3ClusterMatcher has found a match of its respective sequence.
389 if (Arrays.stream(mPendingMatches).noneMatch(l -> l.isEmpty())) {
391 final SimpleDirectedWeightedGraph<Vertex, DefaultWeightedEdge> graph =
392 new SimpleDirectedWeightedGraph<>(DefaultWeightedEdge.class);
393 // Add a vertex for each match found by all cluster matchers.
394 // And maintain an array to keep track of what cluster matcher each vertex corresponds to
395 final List<Vertex>[] vertices = new List[mPendingMatches.length];
396 for (int i = 0; i < mPendingMatches.length; i++) {
397 vertices[i] = new ArrayList<>();
398 for (List<PcapPacket> sequence : mPendingMatches[i]) {
399 Vertex v = new Vertex(sequence);
400 vertices[i].add(v); // retain reference for later when we are to add edges
401 graph.addVertex(v); // add to vertex to graph
404 // Add dummy source and sink vertices to facilitate search.
405 final Vertex source = new Vertex(null);
406 final Vertex sink = new Vertex(null);
407 graph.addVertex(source);
408 graph.addVertex(sink);
409 // The source is connected to all vertices that wrap the sequences detected by cluster matcher at index 0.
410 // Note: zero cost edges as this is just a dummy link to facilitate search from a common start node.
411 for (Vertex v : vertices[0]) {
412 DefaultWeightedEdge edge = graph.addEdge(source, v);
413 graph.setEdgeWeight(edge, 0.0);
415 // Similarly, all vertices that wrap the sequences detected by the last cluster matcher of the signature
416 // are connected to the sink node.
417 for (Vertex v : vertices[vertices.length-1]) {
418 DefaultWeightedEdge edge = graph.addEdge(v, sink);
419 graph.setEdgeWeight(edge, 0.0);
421 // Now link sequences detected by the cluster matcher at index i to sequences detected by the cluster
422 // matcher at index i+1 if they obey the timestamp constraint (i.e., that the latter is later in time than
424 for (int i = 0; i < vertices.length; i++) {
426 if (j < vertices.length) {
427 for (Vertex iv : vertices[i]) {
428 PcapPacket ivLast = iv.sequence.get(iv.sequence.size()-1);
429 for (Vertex jv : vertices[j]) {
430 PcapPacket jvFirst = jv.sequence.get(jv.sequence.size()-1);
431 if (ivLast.getTimestamp().isBefore(jvFirst.getTimestamp())) {
432 DefaultWeightedEdge edge = graph.addEdge(iv, jv);
433 // The weight is the duration of the i'th sequence plus the duration between the i'th
434 // and i+1'th sequence.
435 Duration d = Duration.
436 between(iv.sequence.get(0).getTimestamp(), jvFirst.getTimestamp());
437 // Unfortunately weights are double values, so must convert from long to double.
438 // TODO: need nano second precision? If so, use d.toNanos().
439 // TODO: risk of overflow when converting from long to double..?
440 graph.setEdgeWeight(edge, Long.valueOf(d.toMillis()).doubleValue());
442 // Alternative version if we cannot assume that sequences are ordered by timestamp:
443 // if (iv.sequence.stream().max(Comparator.comparing(PcapPacket::getTimestamp)).get()
444 // .getTimestamp().isBefore(jv.sequence.stream().min(
445 // Comparator.comparing(PcapPacket::getTimestamp)).get().getTimestamp())) {
452 // Graph construction complete, run shortest-path to find a (potential) signature match.
453 DijkstraShortestPath<Vertex, DefaultWeightedEdge> dijkstra = new DijkstraShortestPath<>(graph);
454 GraphPath<Vertex, DefaultWeightedEdge> shortestPath = dijkstra.getPath(source, sink);
455 if (shortestPath != null) {
456 // The total weight is the duration between the first packet of the first sequence and the last packet
457 // of the last sequence, so we simply have to compare the weight against the timeframe that we allow
458 // the signature to span. For now we just use the inclusion window we defined for training purposes.
459 // Note however, that we must convert back from double to long as the weight is stored as a double in
461 if (((long)shortestPath.getWeight()) < mInclusionTimeMillis) {
462 // There's a signature match!
463 // Extract the match from the vertices
464 List<List<PcapPacket>> signatureMatch = new ArrayList<>();
465 for(Vertex v : shortestPath.getVertexList()) {
466 if (v == source || v == sink) {
467 // Skip the dummy source and sink nodes.
470 signatureMatch.add(v.sequence);
471 // As there is a one-to-one correspondence between vertices[] and pendingMatches[], we know that
472 // the sequence we've "consumed" for index i of the matched signature is also at index i in
473 // pendingMatches. We must remove it from pendingMatches so that we don't use it to construct
474 // another signature match in a later call.
475 mPendingMatches[signatureMatch.size()-1].remove(v.sequence);
477 // Declare success: notify observers
478 mObservers.forEach(obs -> obs.onSignatureDetected(mSignature,
479 Collections.unmodifiableList(signatureMatch)));
486 * Encapsulates a {@code List<PcapPacket>} so as to allow the list to be used as a vertex in a graph while avoiding
487 * the expensive {@link AbstractList#equals(Object)} calls when adding vertices to the graph.
488 * Using this wrapper makes the incurred {@code equals(Object)} calls delegate to {@link Object#equals(Object)}
489 * instead of {@link AbstractList#equals(Object)}. The net effect is a faster implementation, but the graph will not
490 * recognize two lists that contain the same items--from a value and not reference point of view--as the same
491 * vertex. However, this is fine for our purposes -- in fact restricting it to reference equality seems more
494 private static class Vertex {
495 private final List<PcapPacket> sequence;
496 private Vertex(List<PcapPacket> wrappedSequence) {
497 sequence = wrappedSequence;