Make PcapExporter record timestamps with preserving packet intervals

tools/cooja/java/org/contikios/cooja/Simulation.java

@@ -71,6 +71,7 @@ public class Simulation extends Observable implements Runnable {
   private long speedLimitLastSimtime;
   private long speedLimitLastRealtime;
 
+  private long lastStartTime;
   private long currentSimulationTime = 0;
 
   private String title = null;
@@ -248,7 +249,7 @@ public class Simulation extends Observable implements Runnable {
   }
 
   public void run() {
-    long lastStartTime = System.currentTimeMillis();
+    lastStartTime = System.currentTimeMillis();
     logger.info("Simulation main loop started, system time: " + lastStartTime);
     isRunning = true;
     speedLimitLastRealtime = System.currentTimeMillis();
@@ -1074,6 +1075,16 @@ public class Simulation extends Observable implements Runnable {
     return currentSimulationTime / MILLISECOND;
   }
 
+  /**
+   * Return the actual time value corresponding to an argument which
+   * is a simulation time value in microseconds.
+   *
+   * @return Actual time (microseconds)
+   */
+  public long convertSimTimeToActualTime(long simTime) {
+    return simTime + lastStartTime * 1000;
+  }
+
   /**
    * Changes radio medium of this simulation to the given.
    *

tools/cooja/java/org/contikios/cooja/plugins/RadioLogger.java

@@ -694,8 +694,8 @@ public class RadioLogger extends VisPlugin {
     StringBuilder verbose = new StringBuilder();
 
     /* default analyzer */
-    PacketAnalyzer.Packet packet = new PacketAnalyzer.Packet(data, PacketAnalyzer.MAC_LEVEL);
+    PacketAnalyzer.Packet packet = new PacketAnalyzer.Packet(data, PacketAnalyzer.MAC_LEVEL,
-
+                                                             simulation.convertSimTimeToActualTime(conn.startTime));
     if (analyzePacket(packet, brief, verbose)) {
       if (packet.hasMoreData()) {
         byte[] payload = packet.getPayload();

tools/cooja/java/org/contikios/cooja/plugins/analyzers/IEEE802154Analyzer.java

@@ -69,7 +69,7 @@ public class IEEE802154Analyzer extends PacketAnalyzer {
 
     if (pcapExporter != null) {
       try {
-        pcapExporter.exportPacketData(packet.getPayload());
+        pcapExporter.exportPacketData(packet.getPayload(), packet.getTimestamp());
       } catch (IOException e) {
         logger.error("Could not export PCap data", e);
       }

tools/cooja/java/org/contikios/cooja/plugins/analyzers/PacketAnalyzer.java

@@ -18,6 +18,7 @@ public abstract class PacketAnalyzer {
     int level;
     /* size = length - consumed bytes at tail */
     int size;
+    long ts;  /* in microseconds */
 
     /* L2 addresseses */
     byte[] llsender;
@@ -25,10 +26,11 @@ public abstract class PacketAnalyzer {
 
     byte lastDispatch = 0;
 
-    public Packet(byte[] data, int level) {
+    public Packet(byte[] data, int level, long ts) {
       this.level = level;
       this.data = data.clone();
       this.size = data.length;
+      this.ts = ts;
     }
 
     public void consumeBytesStart(int bytes) {
@@ -79,6 +81,10 @@ public abstract class PacketAnalyzer {
     public byte[] getLLReceiver() {
       return llreceiver;
     }
+
+    public long getTimestamp() {
+      return ts;
+    }
   };
 
   public abstract boolean matchPacket(Packet packet);

tools/cooja/java/org/contikios/cooja/plugins/analyzers/PcapExporter.java

@@ -41,15 +41,15 @@ public class PcapExporter {
     out = null;
   }
 
-  public void exportPacketData(byte[] data) throws IOException {
+  public void exportPacketData(byte[] data, long ts) throws IOException {
     if (out == null) {
       /* pcap file never set, open default */
       openPcap(null);
     }
     try {
       /* pcap packet header */
-      out.writeInt((int) (System.currentTimeMillis() / 1000));
+      out.writeInt((int) (ts / 1000000));
-      out.writeInt((int) ((System.currentTimeMillis() % 1000) * 1000));
+      out.writeInt((int) (ts % 1000000));
       out.writeInt(data.length);
       out.writeInt(data.length);
       /* and the data */