2004-12-14 jrandom

* Reenable the probabalistic drop on the TCP queues to deal with good old
      fashioned bandwidth limiting.  However, by default the probability is
      rigged to reserve 0% of the queue free - meaning we just aggressively
      fail messages in the queue if we're transferring too slowly.  That
      reservation factor can be increased with 'tcp.queueFreeFactor=0.25'
      (or whatever) and the drop code can be disabled with the parameter
      'tcp.dropProbabalistically=false'.
    * Still penalize a peer on tunnel failure, but don't immediately drop
      their capacity to 0.
    * More aggressively ACK duplicates
    * Randomize the timestamper period
    * Display the clock skew on the connection logs when a peer sends it.
    * Allow the timestamper to fix skews of up to 10 minutes
    * Logging

router/java/src/net/i2p/router/RouterVersion.java

@@ -15,9 +15,9 @@ import net.i2p.CoreVersion;
  *
  */
 public class RouterVersion {
-    public final static String ID = "$Revision: 1.109 $ $Date: 2004/12/11 04:26:24 $";
+    public final static String ID = "$Revision: 1.110 $ $Date: 2004/12/13 08:45:52 $";
     public final static String VERSION = "0.4.2.3";
-    public final static long BUILD = 3;
+    public final static long BUILD = 4;
     public static void main(String args[]) {
         System.out.println("I2P Router version: " + VERSION);
         System.out.println("Router ID: " + RouterVersion.ID);

router/java/src/net/i2p/router/peermanager/CapacityCalculator.java

@@ -95,10 +95,10 @@ public class CapacityCalculator extends Calculator {
         if (curFailed != null)
             failed = curFailed.getCurrentEventCount() + curFailed.getLastEventCount();
         if (failed > 0) {
-            if ( (period <= 10*60*1000) && (curFailed.getCurrentEventCount() > 0) )
-                return 0.0d; // their tunnels have failed in the last 0-10 minutes
-            else
-                val -= failed * stretch;
+            //if ( (period <= 10*60*1000) && (curFailed.getCurrentEventCount() > 0) )
+            //    return 0.0d; // their tunnels have failed in the last 0-10 minutes
+            //else
+            val -= failed * stretch;
         }
         
         if ( (period <= 10*60*1000) && (curRejected.getCurrentEventCount() + curRejected.getLastEventCount() > 0) ) {

router/java/src/net/i2p/router/transport/TransportManager.java

@@ -177,6 +177,8 @@ public class TransportManager implements TransportEventListener {
     }
     
     private List orderBids(HashSet bids, OutNetMessage msg) {
+        if (bids.size() <= 1)
+            return new ArrayList(bids);
         // db messages should go as fast as possible, while the others
         // should use as little bandwidth as possible.  
         I2NPMessage message = msg.getMessage();

router/java/src/net/i2p/router/transport/tcp/ConnectionBuilder.java

@@ -410,12 +410,13 @@ public class ConnectionBuilder {
             RouterInfo peer = new RouterInfo();
             peer.readBytes(_rawIn);
             int status = (int)_rawIn.read() & 0xFF;
-            boolean ok = validateStatus(status);
-            if (!ok) return false;
             
             Properties props = DataHelper.readProperties(_rawIn);
             // ignore these now
             
+            boolean ok = validateStatus(status, props);
+            if (!ok) return false;
+            
             Hash readHash = new Hash();
             readHash.readBytes(_rawIn);
             
@@ -564,12 +565,13 @@ public class ConnectionBuilder {
             RouterInfo peer = new RouterInfo();
             peer.readBytes(_rawIn);
             int status = (int)_rawIn.read() & 0xFF;
-            boolean ok = validateStatus(status);
-            if (!ok) return false;
             
             Properties props = DataHelper.readProperties(_rawIn);
             // ignore these now
             
+            boolean ok = validateStatus(status, props);
+            if (!ok) return false;
+            
             Signature sig = new Signature();
             sig.readBytes(_rawIn);
             
@@ -620,7 +622,7 @@ public class ConnectionBuilder {
      *
      * @return true if ok, false if fail()ed
      */
-    private boolean validateStatus(int status) {
+    private boolean validateStatus(int status, Properties props) {
         switch (status) {
             case -1: // EOF
                 fail("Error reading the status from " 
@@ -636,7 +638,7 @@ public class ConnectionBuilder {
             case ConnectionHandler.STATUS_SKEWED:
                 fail("According to " 
                      + _target.getIdentity().calculateHash().toBase64().substring(0,6)
-                     + ", our clock is off");
+                     + ", our clock is off (they think it is " + props.getProperty("SKEW") + ")");
                 return false;
             case ConnectionHandler.STATUS_SIGNATURE_FAILED: // (only for new sessions)
                 fail("Signature failure talking to " 

router/java/src/net/i2p/router/transport/tcp/TCPConnection.java

@@ -185,7 +185,7 @@ public class TCPConnection {
     }
     
     private boolean shouldDropProbabalistically() {
-        return Boolean.valueOf(_context.getProperty("tcp.dropProbabalistically", "false")).booleanValue();
+        return Boolean.valueOf(_context.getProperty("tcp.dropProbabalistically", "true")).booleanValue();
     }
     
     /**
@@ -210,12 +210,34 @@ public class TCPConnection {
         long sendRate = getSendRate();
         long bytesSendableUntilFirstExpire = sendRate * (earliestExpiration - _context.clock().now()) / 1000;
         
-        // try to keep the queue less than half full
-        long excessQueued = bytesQueued - (bytesSendableUntilFirstExpire/2); 
+        // pretend that instead of being able to push bytesSendableUntilFirstExpire,
+        // that we can only push a fraction of that amount, causing us to probabalistically
+        // drop more than is necessary (leaving a fraction of the queue 'free' for bursts)
+        long excessQueued = (long)(bytesQueued - ((double)bytesSendableUntilFirstExpire * (1.0-getQueueFreeFactor()))); 
         if ( (excessQueued > 0) && (_pendingMessages.size() > 1) && (_transport != null) )
             locked_probabalisticDrop(excessQueued);
     }
     
+    /** 
+     * by default, try to keep the queue completely full, but this can be overridden
+     * with the property 'tcp.queueFreeFactor'
+     *
+     */
+    public static final double DEFAULT_QUEUE_FREE_FACTOR = 0.0;
+    
+    private double getQueueFreeFactor() {
+        String factor = _context.getProperty("tcp.queueFreeFactor");
+        if (factor != null) {
+            try {
+                return Double.parseDouble(factor); 
+            } catch (NumberFormatException nfe) {
+                if (_log.shouldLog(Log.WARN))
+                    _log.warn("Invalid tcp.queueFreeFactor [" + factor + "]", nfe);
+            }
+        }
+        return DEFAULT_QUEUE_FREE_FACTOR;
+    }
+    
     /** how many Bps we are sending data to the peer (or 2KBps if we don't know) */
     public long getSendRate() {
         if (_sendRate == null) return 2*1024;