Adding PacketLevelSignatureExtractor.

[pingpong.git] / Code / Projects / PacketLevelSignatureExtractor / src / main / java / edu / uci / iotproject / trafficreassembly / layer2 / Layer2Flow.java

diff --git a/Code/Projects/PacketLevelSignatureExtractor/src/main/java/edu/uci/iotproject/trafficreassembly/layer2/Layer2Flow.java b/Code/Projects/PacketLevelSignatureExtractor/src/main/java/edu/uci/iotproject/trafficreassembly/layer2/Layer2Flow.java
new file mode 100644 (file)
index 0000000..f8c3237
--- /dev/null
+++ b/Code/Projects/PacketLevelSignatureExtractor/src/main/java/edu/uci/iotproject/trafficreassembly/layer2/Layer2Flow.java
@@ -0,0 +1,115 @@
+package edu.uci.iotproject.trafficreassembly.layer2;
+
+import org.pcap4j.core.PcapPacket;
+import org.pcap4j.packet.EthernetPacket;
+import org.pcap4j.util.MacAddress;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Models a layer 2 flow: groups packets exchanged between two specific endpoints (MAC addresses).
+ *
+ * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
+ * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
+ */
+public class Layer2Flow {
+
+    /**
+     * The first endpoint of this layer 2 flow.
+     */
+    private final MacAddress mEndpoint1;
+
+    /**
+     * The second endpoint of this layer 2 flow.
+     */
+    private final MacAddress mEndpoint2;
+
+    /**
+     * Clients observing for changes to this layer 2 flow.
+     */
+    private final List<Layer2FlowObserver> mFlowObservers = new ArrayList<>();
+
+    public Layer2Flow(MacAddress endpoint1, MacAddress endpoint2) {
+        mEndpoint1 = endpoint1;
+        mEndpoint2 = endpoint2;
+    }
+
+    /**
+     * Get the first endpoint of this flow.
+     * @return the first endpoint of this flow.
+     */
+    public MacAddress getEndpoint1() {
+        return mEndpoint1;
+    }
+
+    /**
+     * Get the second endpoint of this flow.
+     * @return the second endpoint of this flow.
+     */
+    public MacAddress getEndpoint2() {
+        return mEndpoint2;
+    }
+
+    /**
+     * Register as an observer of this flow.
+     * @param observer The client that is to be notified whenever this flow changes (has new packets added).
+     */
+    public void addFlowObserver(Layer2FlowObserver observer) {
+        mFlowObservers.add(observer);
+    }
+
+    /**
+     * Deregister as an observer of this flow.
+     * @param observer The client that no longer wishes to be notified whenever this flow changes.
+     */
+    public void removeFlowObserver(Layer2FlowObserver observer) {
+        mFlowObservers.remove(observer);
+    }
+
+    /**
+     * The packets in the flow.
+     */
+    private final List<PcapPacket> mPackets = new ArrayList<>();
+
+    /**
+     * Add a packet to this flow.
+     * @param packet The packet that is to be added to the flow.
+     */
+    public void addPacket(PcapPacket packet) {
+        verifyAddresses(packet);
+        mPackets.add(packet);
+        // Notify flow observers of the new packet
+        mFlowObservers.forEach(o -> o.onNewPacket(this, packet));
+    }
+
+    /**
+     * Get the packets pertaining to this flow.
+     * @return The packets pertaining to this flow.
+     */
+    public List<PcapPacket> getPackets() {
+        return Collections.unmodifiableList(mPackets);
+    }
+
+    /**
+     * Verify that a packet pertains to this flow.
+     * @param packet The packet that is to be verified.
+     */
+    private void verifyAddresses(PcapPacket packet) {
+        EthernetPacket ethPkt = packet.get(EthernetPacket.class);
+        MacAddress srcAddr = ethPkt.getHeader().getSrcAddr();
+        MacAddress dstAddr = ethPkt.getHeader().getDstAddr();
+        if ((mEndpoint1.equals(srcAddr) && mEndpoint2.equals(dstAddr)) ||
+                (mEndpoint1.equals(dstAddr) && mEndpoint2.equals(srcAddr))) {
+            // All is good.
+            return;
+        }
+        throw new IllegalArgumentException("Mismatch in MACs: packet does not pertain to this flow");
+    }
+
+    @Override
+    public String toString() {
+        return getClass().getSimpleName() + String.format(" with mEndpoint1=%s and mEndpoint2=%s", mEndpoint1, mEndpoint2);
+    }
+}