X-Git-Url: http://plrg.eecs.uci.edu/git/?p=pingpong.git;a=blobdiff_plain;f=Code%2FProjects%2FSmartPlugDetector%2Fsrc%2Fmain%2Fjava%2Fedu%2Fuci%2Fiotproject%2FConversation.java;h=f28b8fd2f3167aa64f91957b9ca766f804c09c0a;hp=bbf7616cd2ac2417b208f8442ac11d2d85f0bfb4;hb=eaf6818c383973cdf5fe5a7f6ee88fcd88425cbf;hpb=09cc04baac94b3eb0acafb1f0d5db2447a54c1f4

diff --git a/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/Conversation.java b/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/Conversation.java
index bbf7616..f28b8fd 100644
--- a/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/Conversation.java
+++ b/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/Conversation.java
@@ -1,5 +1,6 @@
 package edu.uci.iotproject;
 
+import edu.uci.iotproject.util.PcapPacketUtils;
 import org.pcap4j.core.PcapPacket;
 import org.pcap4j.packet.IpV4Packet;
 import org.pcap4j.packet.TcpPacket;
@@ -51,6 +52,11 @@ public class Conversation {
      * Used for filtering out retransmissions.
      */
     private final Set<Integer> mSeqNumbers;
+
+    /**
+     * List of pairs FINs and their corresponding ACKs associated with this conversation.
+     */
+    private List<FinAckPair> mFinPackets;
     /* End instance properties */
 
     /**
@@ -68,6 +74,7 @@ public class Conversation {
         this.mServerPort = serverPort;
         this.mPackets = new ArrayList<>();
         this.mSeqNumbers = new HashSet<>();
+        this.mFinPackets = new ArrayList<>();
     }
 
     /**
@@ -80,36 +87,10 @@ public class Conversation {
      *                              seen in a previous packet.
      */
     public void addPacket(PcapPacket packet, boolean ignoreRetransmissions) {
-        // Apply precondition to preserve class invariant: all packets in mPackets must match the 4 tuple that
-        // defines the conversation.
-        // ==== Precondition: verify that packet does indeed pertain to conversation. ====
-        IpV4Packet ipPacket = Objects.requireNonNull(packet.get(IpV4Packet.class));
+        // Precondition: verify that packet does indeed pertain to conversation.
+        onAddPrecondition(packet);
         // For now we only support TCP flows.
         TcpPacket tcpPacket = Objects.requireNonNull(packet.get(TcpPacket.class));
-        String ipSrc = ipPacket.getHeader().getSrcAddr().getHostAddress();
-        String ipDst = ipPacket.getHeader().getDstAddr().getHostAddress();
-        int srcPort = tcpPacket.getHeader().getSrcPort().valueAsInt();
-        int dstPort = tcpPacket.getHeader().getDstPort().valueAsInt();
-        String clientIp, serverIp;
-        int clientPort, serverPort;
-        if (ipSrc.equals(mClientIp)) {
-            clientIp = ipSrc;
-            clientPort = srcPort;
-            serverIp = ipDst;
-            serverPort = dstPort;
-        } else {
-            clientIp = ipDst;
-            clientPort = dstPort;
-            serverIp = ipSrc;
-            serverPort = srcPort;
-        }
-        if (!(clientIp.equals(mClientIp) && clientPort == mClientPort &&
-                serverIp.equals(mServerIp) && serverPort == mServerPort)) {
-            throw new IllegalArgumentException(
-                    String.format("Attempt to add packet that does not pertain to %s",
-                            Conversation.class.getSimpleName()));
-        }
-        // ================================================================================
         int seqNo = tcpPacket.getHeader().getSequenceNumber();
         if (ignoreRetransmissions && mSeqNumbers.contains(seqNo)) {
             // Packet is a retransmission. Ignore it.
@@ -131,6 +112,39 @@ public class Conversation {
         return Collections.unmodifiableList(mPackets);
     }
 
+    /**
+     * Adds a TCP FIN packet to the list of TCP FIN packets associated with this conversation.
+     * @param finPacket The TCP FIN packet that is to be added to (associated with) this conversation.
+     */
+    public void addFinPacket(PcapPacket finPacket) {
+        // Precondition: verify that packet does indeed pertain to conversation.
+        onAddPrecondition(finPacket);
+        mFinPackets.add(new FinAckPair(finPacket));
+    }
+
+    /**
+     * Attempt to ACK any FIN packets held by this conversation.
+     * @param ackPacket The ACK for a FIN previously added to this conversation.
+     */
+    public void attemptAcknowledgementOfFin(PcapPacket ackPacket) {
+        // Precondition: verify that the packet pertains to this conversation.
+        onAddPrecondition(ackPacket);
+        // Mark unack'ed FIN(s) that this ACK matches as ACK'ed (there might be more than one in case of retransmissions..?)
+        mFinPackets.replaceAll(finAckPair -> (!finAckPair.isAcknowledged() && finAckPair.isCorrespondingAckPacket(ackPacket)) ? new FinAckPair(finAckPair.getFinPacket(), ackPacket) : finAckPair);
+    }
+
+    /**
+     * Get if this {@code Conversation} is considered to have been gracefully shut down.
+     * A {@code Conversation} has been gracefully shut down if it contains a FIN+ACK pair for both directions
+     * (client to server, and server to client).
+     * @return {@code true} if the connection has been gracefully shut down, false otherwise.
+     */
+    public boolean isGracefullyShutdown() {
+        //  The conversation has been gracefully shut down if we have recorded a FIN from both the client and the server which have both been ack'ed.
+        return mFinPackets.stream().anyMatch(finAckPair -> finAckPair.isAcknowledged() && PcapPacketUtils.isSource(finAckPair.getFinPacket(), mClientIp, mClientPort)) &&
+                mFinPackets.stream().anyMatch(finAckPair -> finAckPair.isAcknowledged() && PcapPacketUtils.isSource(finAckPair.getFinPacket(), mServerIp, mServerPort));
+    }
+
     // =========================================================================================================
     // We simply reuse equals and hashCode methods of String.class to be able to use this class as a key
     // in a Map.
@@ -157,4 +171,41 @@ public class Conversation {
     public String toString() {
         return String.format("%s:%d %s:%d", mClientIp, mClientPort, mServerIp, mServerPort);
     }
+
+    /**
+     * Invoke to verify that the precondition holds when a caller attempts to add a packet to this {@code Conversation}.
+     * An {@link IllegalArgumentException} is thrown if the precondition is violated.
+     * @param packet the packet to be added to this {@code Conversation}
+     */
+    private void onAddPrecondition(PcapPacket packet) {
+        // Apply precondition to preserve class invariant: all packets in mPackets must match the 4 tuple that
+        // defines the conversation.
+        IpV4Packet ipPacket = Objects.requireNonNull(packet.get(IpV4Packet.class));
+        // For now we only support TCP flows.
+        TcpPacket tcpPacket = Objects.requireNonNull(packet.get(TcpPacket.class));
+        String ipSrc = ipPacket.getHeader().getSrcAddr().getHostAddress();
+        String ipDst = ipPacket.getHeader().getDstAddr().getHostAddress();
+        int srcPort = tcpPacket.getHeader().getSrcPort().valueAsInt();
+        int dstPort = tcpPacket.getHeader().getDstPort().valueAsInt();
+        String clientIp, serverIp;
+        int clientPort, serverPort;
+        if (ipSrc.equals(mClientIp)) {
+            clientIp = ipSrc;
+            clientPort = srcPort;
+            serverIp = ipDst;
+            serverPort = dstPort;
+        } else {
+            clientIp = ipDst;
+            clientPort = dstPort;
+            serverIp = ipSrc;
+            serverPort = srcPort;
+        }
+        if (!(clientIp.equals(mClientIp) && clientPort == mClientPort &&
+                serverIp.equals(mServerIp) && serverPort == mServerPort)) {
+            throw new IllegalArgumentException(
+                    String.format("Attempt to add packet that does not pertain to %s",
+                            Conversation.class.getSimpleName()));
+        }
+    }
+
 }
\ No newline at end of file