Tunnels: Make new tunnel selection round-robin

Remove one-second stickiness, as OCMOSJ caching does the job better
http://zzz.i2p/topics/2454

history.txt

+2020-03-24 zzz
+ * Tunnels: Make new tunnel selection round-robin
+
+2020-03-20 zzz
+ * Tunnels: FragmentHandler cleanup (ticket #2699)
+
+2020-03-17 zzz
+ * i2psnark: Hide non-i2p trackers on details page
+
+2020-03-15 zzz
+ * Ratchet: Stub out ack and ack request blocks
+
 2020-03-01 zzz
  * Console:
    - Disable browser launch on /configclients when a service

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

@@ -18,7 +18,7 @@ public class RouterVersion {
     /** deprecated */
     public final static String ID = "Monotone";
     public final static String VERSION = CoreVersion.VERSION;
-    public final static long BUILD = 3;
+    public final static long BUILD = 4;
 
     /** for example "-test" */
     public final static String EXTRA = "";

router/java/src/net/i2p/router/tunnel/pool/TunnelPool.java

@@ -40,8 +40,7 @@ public class TunnelPool {
     private final TunnelPoolManager _manager;
     protected volatile boolean _alive;
     private long _lifetimeProcessed;
-    private TunnelInfo _lastSelected;
-    private long _lastSelectionPeriod;
+    private int _lastSelectedIdx;
     private final int _expireSkew;
     private long _started;
     private long _lastRateUpdate;
@@ -124,8 +123,6 @@ public class TunnelPool {
         if (_log.shouldLog(Log.WARN))
             _log.warn(toString() + ": Shutdown called");
         _alive = false;
-        _lastSelectionPeriod = 0;
-        _lastSelected = null;
         _context.statManager().removeRateStat(_rateName);
         synchronized (_inProgress) {
             _inProgress.clear();
@@ -152,20 +149,6 @@ public class TunnelPool {
             _settings.readFromProperties(TunnelPoolSettings.PREFIX_OUTBOUND_EXPLORATORY, props);
     }
     
-    /** 
-     * when selecting tunnels, stick with the same one for a brief 
-     * period to allow batching if we can.
-     */
-    private long curPeriod() {
-        long period = _context.clock().now();
-        long ms = period % 1000;
-        if (ms > 500)
-            period = period - ms + 500;
-        else
-            period = period - ms;
-        return period;
-    }
-    
     private long getLifetime() { return System.currentTimeMillis() - _started; }
     
     /**
@@ -180,33 +163,24 @@ public class TunnelPool {
     private TunnelInfo selectTunnel(boolean allowRecurseOnFail) {
         boolean avoidZeroHop = !_settings.getAllowZeroHop();
         
-        long period = curPeriod();
         synchronized (_tunnels) {
-            if (_lastSelectionPeriod == period) {
-                if ( (_lastSelected != null) && 
-                     (_lastSelected.getExpiration() > period) &&
-                     (_tunnels.contains(_lastSelected)) )
-                    return _lastSelected;
-            }
-            _lastSelectionPeriod = period;
-            _lastSelected = null;
-
             if (_tunnels.isEmpty()) {
                 if (_log.shouldLog(Log.WARN))
                     _log.warn(toString() + ": No tunnels to select from");
             } else {
-                Collections.shuffle(_tunnels, _context.random());
                 
                 // if there are nonzero hop tunnels and the zero hop tunnels are fallbacks, 
                 // avoid the zero hop tunnels
                 TunnelInfo backloggedTunnel = null;
                 if (avoidZeroHop) {
                     for (int i = 0; i < _tunnels.size(); i++) {
-                        TunnelInfo info = _tunnels.get(i);
+                        _lastSelectedIdx++;
+                        if (_lastSelectedIdx >= _tunnels.size())
+                            _lastSelectedIdx = 0;
+                        TunnelInfo info = _tunnels.get(_lastSelectedIdx);
                         if ( (info.getLength() > 1) && (info.getExpiration() > _context.clock().now()) ) {
                             // avoid outbound tunnels where the 1st hop is backlogged
                             if (_settings.isInbound() || !_context.commSystem().isBacklogged(info.getPeer(1))) {
-                                _lastSelected = info;
                                 return info;
                             } else {
                                 backloggedTunnel = info;
@@ -229,7 +203,6 @@ public class TunnelPool {
                         if (_settings.isInbound() || info.getLength() <= 1 ||
                             !_context.commSystem().isBacklogged(info.getPeer(1))) {
                             //_log.debug("Selecting tunnel: " + info + " - " + _tunnels);
-                            _lastSelected = info;
                             return info;
                         } else {
                             backloggedTunnel = info;
@@ -505,10 +478,6 @@ public class TunnelPool {
             if (_settings.isInbound() && !_settings.isExploratory())
                 ls = locked_buildNewLeaseSet();
             remaining = _tunnels.size();
-            if (_lastSelected == info) {
-                _lastSelected = null;
-                _lastSelectionPeriod = 0;
-            }
         }
 
         _manager.getExecutor().repoll();
@@ -573,10 +542,6 @@ public class TunnelPool {
                 return;
             if (_settings.isInbound() && !_settings.isExploratory())
                 ls = locked_buildNewLeaseSet();
-            if (_lastSelected == cfg) {
-                _lastSelected = null;
-                _lastSelectionPeriod = 0;
-            }
         }
         
         _manager.tunnelFailed();