package edu.uci.iotproject.detection.layer2;
+import edu.uci.iotproject.analysis.TriggerTrafficExtractor;
import edu.uci.iotproject.trafficreassembly.layer2.Layer2FlowReassembler;
import edu.uci.iotproject.trafficreassembly.layer2.Layer2Flow;
import edu.uci.iotproject.trafficreassembly.layer2.Layer2FlowReassemblerObserver;
* of {@link #mCluster} and has so far matched {@code j} packets of that particular sequence.
*/
private final Map<Layer2Flow, Layer2SequenceMatcher[][]> mPerFlowSeqMatchers = new HashMap<>();
+ private final Map<Layer2Flow, List<Layer2RangeMatcher>> mPerFlowRangeMatcher = new HashMap<>();
private final Function<Layer2Flow, Boolean> mFlowFilter;
+ /**
+ * Specifying range-based instead of conservative exact matching.
+ */
+ private final boolean mRangeBased;
+
+ /**
+ * Epsilon value used by the DBSCAN algorithm; it is used again for range-based matching here.
+ */
+ private final double mEps;
+
+ private int mInclusionTimeMillis;
+
+ /**
+ * Keeping track of maximum number of skipped packets
+ */
+ private int mMaxSkippedPackets;
+ private List<Integer> mSkippedPackets;
+
+ private int mLimitSkippedPackets;
+
+ /**
+ * Router's WLAN MAC.
+ */
+ private String mTrainingRouterWlanMac;
+ private String mRouterWlanMac;
+
/**
* Create a new {@link Layer2ClusterMatcher} that attempts to find occurrences of {@code cluster}'s members.
* @param cluster The sequence mutations that the new {@link Layer2ClusterMatcher} should search for.
*/
- public Layer2ClusterMatcher(List<List<PcapPacket>> cluster) {
+ public Layer2ClusterMatcher(List<List<PcapPacket>> cluster, String trainingRouterWlanMac, String routerWlanMac, int inclusionTimeMillis,
+ boolean isRangeBased, double eps, int limitSkippedPackets) {
// Consider all flows if no flow filter specified.
- this(cluster, flow -> true);
+ this(cluster, trainingRouterWlanMac, routerWlanMac, flow -> true, inclusionTimeMillis, isRangeBased, eps,
+ limitSkippedPackets);
}
/**
* Create a new {@link Layer2ClusterMatcher} that attempts to find occurrences of {@code cluster}'s members.
* @param cluster The sequence mutations that the new {@link Layer2ClusterMatcher} should search for.
+ * @param trainingRouterWlanMac The training router's WLAN MAC (used for determining the direction of packets).
+ * @param routerWlanMac The target trace router's WLAN MAC (used for determining the direction of packets).
* @param flowFilter A filter that defines what {@link Layer2Flow}s the new {@link Layer2ClusterMatcher} should
* search for {@code cluster}'s members in. If {@code flowFilter} returns {@code true}, the flow
* will be included (searched). Note that {@code flowFilter} is only queried once for each flow,
* namely when the {@link Layer2FlowReassembler} notifies the {@link Layer2ClusterMatcher} about
* the new flow. This functionality may for example come in handy when one only wants to search
* for matches in the subset of flows that involves a specific (range of) MAC(s).
+ * @param inclusionTimeMillis Packet inclusion time limit for matching.
+ * @param isRangeBased The boolean that decides if it is range-based vs. strict matching.
+ * @param eps The epsilon value used in the DBSCAN algorithm.
*/
- public Layer2ClusterMatcher(List<List<PcapPacket>> cluster, Function<Layer2Flow, Boolean> flowFilter) {
- super(cluster);
+ public Layer2ClusterMatcher(List<List<PcapPacket>> cluster, String trainingRouterWlanMac, String routerWlanMac,
+ Function<Layer2Flow, Boolean> flowFilter, int inclusionTimeMillis, boolean isRangeBased,
+ double eps, int limitSkippedPackets) {
+ super(cluster, isRangeBased);
mFlowFilter = flowFilter;
+ mTrainingRouterWlanMac = trainingRouterWlanMac;
+ mRouterWlanMac = routerWlanMac;
+ mRangeBased = isRangeBased;
+ mEps = eps;
+ mInclusionTimeMillis =
+ inclusionTimeMillis == 0 ? TriggerTrafficExtractor.INCLUSION_WINDOW_MILLIS : inclusionTimeMillis;
+ mMaxSkippedPackets = 0;
+ mSkippedPackets = new ArrayList<>();
+ // Give integer's MAX_VALUE if -1
+ mLimitSkippedPackets = limitSkippedPackets == -1 ? Integer.MAX_VALUE : limitSkippedPackets;
}
@Override
public void onNewPacket(Layer2Flow flow, PcapPacket newPacket) {
+ if (mRangeBased) {
+ rangeBasedMatching(flow, newPacket);
+ } else {
+ conservativeMatching(flow, newPacket);
+ }
+ }
+
+ private void conservativeMatching(Layer2Flow flow, PcapPacket newPacket) {
if (mPerFlowSeqMatchers.get(flow) == null) {
// If this is the first time we encounter this flow, we need to set up sequence matchers for it.
// All sequences of the cluster have the same length, so we only need to compute the length of the nested
Layer2SequenceMatcher[][] matchers = new Layer2SequenceMatcher[mCluster.size()][mCluster.get(0).size()];
// Prepare a "state 0" sequence matcher for each sequence variation in the cluster.
for (int i = 0; i < matchers.length; i++) {
- matchers[i][0] = new Layer2SequenceMatcher(mCluster.get(i));
+ matchers[i][0] = new Layer2SequenceMatcher(mCluster.get(i), mInclusionTimeMillis, mTrainingRouterWlanMac,
+ mRouterWlanMac);
}
// Associate the new sequence matcher table with the new flow
mPerFlowSeqMatchers.put(flow, matchers);
boolean matched = sm.matchPacket(newPacket);
if (matched) {
if (sm.getMatchedPacketsCount() == sm.getTargetSequencePacketCount()) {
- // Sequence matcher has a match. Report it to observers.
- mObservers.forEach(o -> o.onMatch(this, sm.getMatchedPackets()));
+ // Update maximum skipped packets
+ boolean stillMatch = checkMaxSkippedPackets(flow.getPackets(), sm.getMatchedPackets());
+ if (stillMatch) {
+ // Sequence matcher has a match. Report it to observers.
+ mObservers.forEach(o -> o.onMatch(this, sm.getMatchedPackets()));
+ }
// Remove the now terminated sequence matcher.
matchers[i][j] = null;
} else {
// We always want to have a sequence matcher in state 0, regardless of if the one that advanced
// from state zero completed its matching or if it replaced a different one in state 1 or not.
if (sm.getMatchedPacketsCount() == 1) {
- matchers[i][j] = new Layer2SequenceMatcher(sm.getTargetSequence());
+ matchers[i][j] = new Layer2SequenceMatcher(sm.getTargetSequence(), mInclusionTimeMillis,
+ mTrainingRouterWlanMac, mRouterWlanMac);
}
}
}
}
}
+ // Update the maximum number of skipped packets.
+ private boolean checkMaxSkippedPackets(List<PcapPacket> flowPackets, List<PcapPacket> matchedPackets) {
+ // Count number of skipped packets by looking into
+ // the difference of indices of two matched packets.
+ boolean stillMatch = true;
+ for(int i = 1; i < matchedPackets.size(); ++i) {
+ int currIndex = flowPackets.indexOf(matchedPackets.get(i-1));
+ int nextIndex = flowPackets.indexOf(matchedPackets.get(i));
+ int skippedPackets = nextIndex - currIndex;
+ if (mMaxSkippedPackets < skippedPackets) {
+ mMaxSkippedPackets = skippedPackets;
+ }
+ if (mLimitSkippedPackets < skippedPackets) {
+ stillMatch = false;
+ }
+ mSkippedPackets.add(skippedPackets);
+ }
+ return stillMatch;
+ }
+
+ private void rangeBasedMatching(Layer2Flow flow, PcapPacket newPacket) {
+ // TODO: For range-based matching, we need to create a new matcher every time we see the first element of
+ // the sequence (between lower and upper bounds).
+ if (mPerFlowRangeMatcher.get(flow) == null) {
+ // If this is the first time we encounter this flow, we need to set up a list of sequence matchers.
+ List<Layer2RangeMatcher> listMatchers = new ArrayList<>();
+ // Prepare a "state 0" sequence matcher.
+ Layer2RangeMatcher matcher = new Layer2RangeMatcher(mCluster.get(0), mCluster.get(1),
+ mInclusionTimeMillis, mEps, mTrainingRouterWlanMac, mRouterWlanMac);
+ listMatchers.add(matcher);
+ // Associate the new sequence matcher table with the new flow.
+ mPerFlowRangeMatcher.put(flow, listMatchers);
+ }
+ // Fetch table that contains sequence matchers for this flow.
+ List<Layer2RangeMatcher> listMatchers = mPerFlowRangeMatcher.get(flow);
+ // Add a new matcher if all matchers have already advanced to the next stage.
+ // We always need a new matcher to match from NO packets.
+ boolean addOneArray = true;
+ for(Layer2RangeMatcher matcher : listMatchers) {
+ if (matcher.getMatchedPacketsCount() == 0) {
+ addOneArray = false;
+ }
+ }
+ // Add the new matcher into the list
+ if (addOneArray) {
+ Layer2RangeMatcher newMatcher = new Layer2RangeMatcher(mCluster.get(0), mCluster.get(1),
+ mInclusionTimeMillis, mEps, mTrainingRouterWlanMac, mRouterWlanMac);
+ listMatchers.add(newMatcher);
+ }
+ // Present packet to the sequence matchers.
+ // Make a shallow copy of the list so that we can clean up the actual list when a matcher is terminated.
+ // Otherwise, we would get an exception for changing the list while iterating on it.
+ List<Layer2RangeMatcher> listMatchersCopy = new ArrayList<>(listMatchers);
+ Layer2RangeMatcher previousMatcher = null;
+ for(Layer2RangeMatcher matcher : listMatchersCopy) {
+ Layer2RangeMatcher sm = matcher;
+ // Check if no packets are matched yet or if there are matched packets, the next packet to be matched
+ // has to be later than the last matched packet.
+ // In most traces, a small amount of the packets appear out of order (with regards to their timestamp),
+ // which is why this check is required.
+ // Obviously it would not be needed if packets where guaranteed to be processed in timestamp
+ // order here.
+ if (sm.getMatchedPacketsCount() == 0 ||
+ newPacket.getTimestamp().isAfter(sm.getLastPacket().getTimestamp())) {
+ boolean matched = sm.matchPacket(newPacket);
+ if (matched) {
+ // BUG: found on May 29, 2019
+ // We need to remove a previous match if the current match is later in time.
+ // This is done only if we have matched at least 1 packet (we are about to match the second or
+ // later packets) and we match for the same packet position in the signature (check the size!).
+ if (previousMatcher != null && sm.getMatchedPacketsCount() > 1 &&
+ previousMatcher.getMatchedPacketsCount() == sm.getMatchedPacketsCount()) {
+ List<PcapPacket> previouslyMatchedPackets = previousMatcher.getMatchedPackets();
+ List<PcapPacket> currentlyMatchedPackets = sm.getMatchedPackets();
+ // We need to check 1 packet before the last matched packet from the previous matcher.
+ int packetIndexToCheck = (sm.getMatchedPacketsCount() - 1) - 1;
+ if (currentlyMatchedPackets.get(packetIndexToCheck).getTimestamp().
+ isAfter(previouslyMatchedPackets.get(packetIndexToCheck).getTimestamp())) {
+ listMatchers.remove(previousMatcher);
+ }
+ }
+ if (sm.getMatchedPacketsCount() == sm.getTargetSequencePacketCount()) {
+ // Update maximum skipped packets
+ boolean stillMatch = checkMaxSkippedPackets(flow.getPackets(), sm.getMatchedPackets());
+ if (stillMatch) {
+ // Sequence matcher has a match. Report it to observers.
+ mObservers.forEach(o -> o.onMatch(this, sm.getMatchedPackets()));
+ }
+ // Terminate sequence matcher since matching is complete.
+ listMatchers.remove(matcher);
+ }
+ previousMatcher = sm;
+ }
+ }
+ }
+ }
@Override
protected List<List<PcapPacket>> pruneCluster(List<List<PcapPacket>> cluster) {
System.out.println(">>> IGNORING FLOW: " + newFlow + " <<<");
}
}
+
+ /**
+ * Return the maximum number of skipped packets.
+ */
+ public int getMaxSkippedPackets() {
+ return mMaxSkippedPackets;
+ }
+
+ /**
+ * Return the numbers of skipped packets.
+ */
+ public List<Integer> getSkippedPackets() {
+ return mSkippedPackets;
+ }
}
projects / pingpong.git / blobdiff