import java.util.HashMap;
import java.util.List;
import java.util.Map;
-import java.util.concurrent.CopyOnWriteArrayList;
import java.util.function.Function;
/**
* 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, Layer2RangeMatcher[]> mPerFlowRangeMatcher = new HashMap<>();
private final Map<Layer2Flow, List<Layer2RangeMatcher>> mPerFlowRangeMatcher = new HashMap<>();
private final Function<Layer2Flow, Boolean> mFlowFilter;
private int mInclusionTimeMillis;
+ /**
+ * Keeping track of maximum number of skipped packets
+ */
+ private int mMaxSkippedPackets;
+// private List<Integer> mMaxSkippedPackets;
+
+ private int mLimitSkippedPackets;
+
/**
* 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, int inclusionTimeMillis,
- boolean isRangeBased, double eps) {
+ boolean isRangeBased, double eps, int limitSkippedPackets) {
// Consider all flows if no flow filter specified.
- this(cluster, flow -> true, inclusionTimeMillis, isRangeBased, eps);
+ this(cluster, flow -> true, inclusionTimeMillis, isRangeBased, eps, limitSkippedPackets);
}
/**
* @param eps The epsilon value used in the DBSCAN algorithm.
*/
public Layer2ClusterMatcher(List<List<PcapPacket>> cluster, Function<Layer2Flow, Boolean> flowFilter,
- int inclusionTimeMillis, boolean isRangeBased, double eps) {
+ int inclusionTimeMillis, boolean isRangeBased, double eps, int limitSkippedPackets) {
super(cluster, isRangeBased);
mFlowFilter = flowFilter;
mRangeBased = isRangeBased;
mEps = eps;
mInclusionTimeMillis =
inclusionTimeMillis == 0 ? TriggerTrafficExtractor.INCLUSION_WINDOW_MILLIS : inclusionTimeMillis;
+ mMaxSkippedPackets = 0;
+// mMaxSkippedPackets = new ArrayList<>();
+ // Give integer's MAX_VALUE if -1
+ mLimitSkippedPackets = limitSkippedPackets == -1 ? Integer.MAX_VALUE : limitSkippedPackets;
}
@Override
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 {
}
}
+ // 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;
+ }
+// mMaxSkippedPackets.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).
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()));
+ }
// Terminate sequence matcher since matching is complete.
listMatchers.remove(matcher);
}
System.out.println(">>> IGNORING FLOW: " + newFlow + " <<<");
}
}
+
+ /**
+ * Return the maximum number of skipped packets.
+ */
+ public int getMaxSkippedPackets() {
+ return mMaxSkippedPackets;
+ }
+// public List<Integer> getMaxSkippedPackets() {
+// return mMaxSkippedPackets;
+// }
}