--- /dev/null
+package edu.uci.iotproject.detection.layer2;
+
+import edu.uci.iotproject.analysis.TriggerTrafficExtractor;
+import edu.uci.iotproject.util.PcapPacketUtils;
+import org.pcap4j.core.PcapPacket;
+import org.pcap4j.util.MacAddress;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Attempts to detect the presence of a specific packet sequence in the set of packets provided through multiple calls
+ * to {@link #matchPacket(PcapPacket)}, considering only layer 2 information. This class has the same flavor as the
+ * {@link Layer2SequenceMatcher} class.
+ *
+ * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
+ * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
+ */
+public class Layer2RangeMatcher extends Layer2AbstractMatcher {
+ /**
+ * The range this {@link Layer2RangeMatcher} is searching for.
+ */
+ private final List<PcapPacket> mLowerBound;
+ private final List<PcapPacket> mUpperBound;
+ private final double mEps;
+
+ /**
+ * Create a {@code Layer2RangeMatcher}.
+ * @param lowerBound The lower bound of the sequence to match against (search for).
+ * @param upperBound The upper bound of the sequence to match against (search for).
+ * @param eps The epsilon value used in the DBSCAN algorithm.
+ */
+ public Layer2RangeMatcher(List<PcapPacket> lowerBound, List<PcapPacket> upperBound, double eps) {
+ // TODO: Just use the lower bound since both lower and upper bounds' packets essentially have the same direction
+ // TODO: for the same position in the array. Both arrays also have the same length.
+ super(lowerBound);
+ mLowerBound = lowerBound;
+ mUpperBound = upperBound;
+ mEps = eps;
+ }
+
+ /**
+ * Attempt to advance this {@code Layer2RangeMatcher} by matching {@code packet} against the packet that this
+ * {@code Layer2RangeMatcher} expects as the next packet of the sequence it is searching for.
+ * @param packet
+ * @return {@code true} if this {@code Layer2SequenceMatcher} could advance by adding {@code packet} to its set of
+ * matched packets, {@code false} otherwise.
+ */
+ public boolean matchPacket(PcapPacket packet) {
+ if (getMatchedPacketsCount() == getTargetSequencePacketCount()) {
+ // We already matched the entire sequence, so we can't match any more packets.
+ return false;
+ }
+
+ // Verify that new packet pertains to same flow as previously matched packets, if any.
+ if (getMatchedPacketsCount() > 0) {
+ MacAddress pktSrc = PcapPacketUtils.getEthSrcAddr(packet);
+ MacAddress pktDst = PcapPacketUtils.getEthDstAddr(packet);
+ MacAddress earlierPktSrc = PcapPacketUtils.getEthSrcAddr(mMatchedPackets.get(0));
+ MacAddress earlierPktDst = PcapPacketUtils.getEthDstAddr(mMatchedPackets.get(0));
+ if (!(pktSrc.equals(earlierPktSrc) && pktDst.equals(earlierPktDst) ||
+ pktSrc.equals(earlierPktDst) && pktDst.equals(earlierPktSrc))) {
+ return false;
+ }
+ }
+
+ // Get representative of the packet we expect to match next.
+ PcapPacket expectedLowerBound = mLowerBound.get(mMatchedPackets.size());
+ PcapPacket expectedUpperBound = mUpperBound.get(mMatchedPackets.size());
+ // First verify if the received packet has the length we're looking for (the length should be within the range).
+// if (expectedLowerBound.getOriginalLength() - (int) mEps <= packet.getOriginalLength() &&
+// packet.getOriginalLength() <= expectedUpperBound.getOriginalLength() + (int) mEps){
+ if (expectedLowerBound.getOriginalLength() - (int) mEps <= packet.getOriginalLength() &&
+ packet.getOriginalLength() <= expectedUpperBound.getOriginalLength() + (int) mEps){
+ // If this is the first packet, we only need to verify that its length is correct. Time constraints are
+ // obviously satisfied as there are no previous packets. Furthermore, direction matches by definition as we
+ // don't know the MAC of the device (or phone) in advance, so we can't enforce a rule saying "first packet
+ // must originate from this particular MAC".
+ if (getMatchedPacketsCount() == 0) {
+ // Store packet as matched and advance.
+ mMatchedPackets.add(packet);
+ return true;
+ }
+ // Check if direction of packet matches expected direction.
+ boolean actualDirection = getPacketDirection(mMatchedPackets.get(getMatchedPacketsCount()-1),
+ mPacketDirections[getMatchedPacketsCount()-1], packet);
+ boolean expectedDirection = mPacketDirections[getMatchedPacketsCount()];
+ if (actualDirection != expectedDirection) {
+ return false;
+ }
+ // Next apply timing constraints:
+ // 1: to be a match, the packet must have a later timestamp than any other packet currently matched
+ // 2: does adding the packet cause the max allowed time between first packet and last packet to be exceeded?
+ if (!packet.getTimestamp().isAfter(mMatchedPackets.get(getMatchedPacketsCount()-1).getTimestamp())) {
+ return false;
+ }
+ if (packet.getTimestamp().isAfter(mMatchedPackets.get(0).getTimestamp().
+ plusMillis(TriggerTrafficExtractor.INCLUSION_WINDOW_MILLIS))) {
+ return false;
+ }
+ // If we made it here, it means that this packet has the expected length, direction, and obeys the timing
+ // constraints, so we store it and advance.
+ mMatchedPackets.add(packet);
+ if (mMatchedPackets.size() == mLowerBound.size()) {
+ // TODO report (to observers?) that we are done?
+ }
+ return true;
+ }
+ return false;
+ }
+
+ public int getTargetSequencePacketCount() {
+ return mLowerBound.size();
+ }
+
+ public List<PcapPacket> getTargetLowerBound() {
+ return mLowerBound;
+ }
+
+ public List<PcapPacket> getTargetUpperBound() {
+ return mLowerBound;
+ }
+}
projects / pingpong.git / blobdiff