SSU2: Hook in IMF Bloom filter to detect dups

Call messagePartiallyReceived() even for dups or expired messages
so an ack is generated.

router/java/src/net/i2p/router/transport/udp/InboundMessageFragments.java

@@ -83,6 +83,32 @@ class InboundMessageFragments /*implements UDPTransport.PartialACKSource */{
         }
     }
 
+    /**
+     * This message was received.
+     * SSU 2 only.
+     * No stats updated here, caller should handle stats.
+     *
+     * @return true if this message was a duplicate
+     * @since 0.9.54
+     */
+
+    public boolean messageReceived(long messageID) {
+        return _recentlyCompletedMessages.add(messageID);
+    }
+
+    /**
+     * Was this message recently received?
+     * SSU 2 only.
+     * No stats updated here, caller should handle stats.
+     *
+     * @return true if this message was recently received.
+     * @since 0.9.54
+     */
+
+    public boolean wasRecentlyReceived(long messageID) {
+        return _recentlyCompletedMessages.isKnown(messageID);
+    }
+
     /**
      * Pull the fragments and ACKs out of the authenticated data packet
      */

router/java/src/net/i2p/router/transport/udp/PeerState2.java

@@ -435,7 +435,14 @@ public class PeerState2 extends PeerState implements SSU2Payload.PayloadCallback
             _log.debug("Got I2NP block: " + msg);
         // 9 byte header
         int size = msg.getMessageSize() - 7;
-        messageFullyReceived(msg.getUniqueId(), size);
+        long messageId = msg.getUniqueId();
+        messageFullyReceived(messageId, size);
+        if (_transport.getInboundFragments().messageReceived(messageId)) {
+            _context.statManager().addRateData("udp.ignoreRecentDuplicate", 1);
+            if (_log.shouldInfo())
+                _log.info("Got dup msg: " + messageId + " on " + this);
+            return;
+        }
         // complete message, skip IMF and MessageReceiver
         _transport.messageReceived(msg, null, _remotePeer, 0, size);
     }
@@ -446,13 +453,20 @@ public class PeerState2 extends PeerState implements SSU2Payload.PayloadCallback
         InboundMessageState state;
         boolean messageComplete = false;
         boolean messageExpired = false;
-        boolean messageDup = false;
+        boolean messageDup;
 
         synchronized (_inboundMessages) {
             state = _inboundMessages.get(messageId);
             if (state == null) {
-                state = new InboundMessageState(_context, messageId, _remotePeer, data, off, len, frag, isLast);
-                _inboundMessages.put(messageId, state);
+                // Bloom filter in router will catch it, but use IMF's Bloom filter
+                // to save resources here
+                messageDup = _transport.getInboundFragments().wasRecentlyReceived(messageId);
+                if (messageDup) {
+                    state = null;
+                } else {
+                    state = new InboundMessageState(_context, messageId, _remotePeer, data, off, len, frag, isLast);
+                    _inboundMessages.put(messageId, state);
+                }
             } else {
                 messageDup = state.hasFragment(frag);
                 if (!messageDup) {
@@ -471,22 +485,38 @@ public class PeerState2 extends PeerState implements SSU2Payload.PayloadCallback
         }
 
         if (messageDup) {
+            messagePartiallyReceived();
+            // Only update stats for the first fragment,
+            // otherwise it wildly overstates things
+            if (frag == 0)
+                _context.statManager().addRateData("udp.ignoreRecentDuplicate", 1);
             synchronized(this) {
                 _packetsReceivedDuplicate++;
             }
-            if (_log.shouldWarn())
-                _log.warn("dup fragment rcvd: " + frag + " for " + state);
+            if (_log.shouldInfo()) {
+                if (state != null)
+                    _log.info("dup fragment rcvd: " + frag + " for " + state);
+                else
+                    _log.info("dup fragment rcvd: " + messageId + ' ' + frag + " on " + this);
+            }
             return;
         }
 
         if (messageComplete) {
                 messageFullyReceived(messageId, state.getCompleteSize());
+                if (_transport.getInboundFragments().messageReceived(messageId)) {
+                    _context.statManager().addRateData("udp.ignoreRecentDuplicate", 1);
+                    if (_log.shouldInfo())
+                        _log.info("Got dup msg: " + messageId + " on " + this);
+                    return;
+                }
                 if (_log.shouldDebug())
                 _log.debug("Message received completely!  " + state);
             _context.statManager().addRateData("udp.receivedCompleteTime", state.getLifetime(), state.getLifetime());
             _context.statManager().addRateData("udp.receivedCompleteFragments", state.getFragmentCount(), state.getLifetime());
             receiveMessage(state);
         } else if (messageExpired) {
+            messagePartiallyReceived();
             if (_log.shouldWarn())
                 _log.warn("Message expired while only being partially read: " + state);
             _context.messageHistory().droppedInboundMessage(state.getMessageId(), state.getFrom(), "expired while partially read: " + state.toString());

router/java/src/net/i2p/router/transport/udp/UDPTransport.java

@@ -3463,6 +3463,13 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
         return _testManager;
     }
 
+    /**
+     *  @since 0.9.54
+     */
+    InboundMessageFragments getInboundFragments() {
+        return _inboundFragments;
+    }
+
     /**
      * Does nothing
      * @deprecated as of 0.9.31