Another tweak to cluster I/O rules.

node/Cluster.cpp

@@ -516,7 +516,7 @@ void Cluster::broadcastNetworkConfigChunk(const void *chunk,unsigned int len)
 	}
 }
 
-int Cluster::prepSendViaCluster(const Address &toPeerAddress,uint64_t &mostRecentTs,void *peerSecret)
+int Cluster::checkSendViaCluster(const Address &toPeerAddress,uint64_t &mostRecentTs,void *peerSecret)
 {
 	const uint64_t now = RR->node->now();
 	mostRecentTs = 0;

node/Cluster.hpp

@@ -289,7 +289,7 @@ public:
 	 * @param peerSecret Result: Buffer to fill with peer secret on valid return value, must be at least ZT_PEER_SECRET_KEY_LENGTH bytes
 	 * @return -1 if cluster does not know this peer, or a member ID to pass to sendViaCluster()
 	 */
-	int prepSendViaCluster(const Address &toPeerAddress,uint64_t &mostRecentTs,void *peerSecret);
+	int checkSendViaCluster(const Address &toPeerAddress,uint64_t &mostRecentTs,void *peerSecret);
 
 	/**
 	 * Send data via cluster front plane (packet head or fragment)

node/Peer.hpp

@@ -137,7 +137,7 @@ public:
 	 * Get the best current direct path
 	 *
 	 * @param now Current time
-	 * @param includeDead If true, include even expired paths
+	 * @param includeExpired If true, include even expired paths
 	 * @return Best current path or NULL if none
 	 */
 	SharedPtr<Path> getBestPath(uint64_t now,bool includeExpired);

node/Switch.cpp

@@ -691,10 +691,13 @@ bool Switch::_trySend(Packet &packet,bool encrypt)
 	SharedPtr<Path> viaPath;
 	const uint64_t now = RR->node->now();
 	const Address destination(packet.destination());
+
 #ifdef ZT_ENABLE_CLUSTER
 	uint64_t clusterMostRecentTs = 0;
 	int clusterMostRecentMemberId = -1;
 	uint8_t clusterPeerSecret[ZT_PEER_SECRET_KEY_LENGTH];
+	if (RR->cluster)
+		clusterMostRecentMemberId = RR->cluster->checkSendViaCluster(destination,clusterMostRecentTs,clusterPeerSecret);
 #endif
 
 	const SharedPtr<Peer> peer(RR->topology->getPeer(destination));
@@ -708,37 +711,40 @@ bool Switch::_trySend(Packet &packet,bool encrypt)
 
 		viaPath = peer->getBestPath(now,false);
 		if ( (viaPath) && (!viaPath->alive(now)) && (!RR->topology->isUpstream(peer->identity())) ) {
-			if ((now - viaPath->lastOut()) > std::max((now - viaPath->lastIn()) * 4,(uint64_t)ZT_PATH_MIN_REACTIVATE_INTERVAL))
-				peer->attemptToContactAt(viaPath->localAddress(),viaPath->address(),now);
+#ifdef ZT_ENABLE_CLUSTER
+			if ((clusterMostRecentMemberId < 0)||(viaPath->lastIn() > clusterMostRecentTs)) {
+#endif
+				if ((now - viaPath->lastOut()) > std::max((now - viaPath->lastIn()) * 4,(uint64_t)ZT_PATH_MIN_REACTIVATE_INTERVAL)) {
+					peer->attemptToContactAt(viaPath->localAddress(),viaPath->address(),now);
+					viaPath->sent(now);
+				}
+#ifdef ZT_ENABLE_CLUSTER
+			}
+#endif
 			viaPath.zero();
 		}
 
-		if (!viaPath) {
-			const SharedPtr<Peer> relay(RR->topology->getUpstreamPeer());
-			if ( (!relay) || (!(viaPath = relay->getBestPath(now,false))) )
-				viaPath = peer->getBestPath(now,true);
-		}
-
 #ifdef ZT_ENABLE_CLUSTER
-		if (RR->cluster)
-			clusterMostRecentMemberId = RR->cluster->prepSendViaCluster(destination,clusterMostRecentTs,clusterPeerSecret);
 		if (clusterMostRecentMemberId >= 0) {
 			if ((viaPath)&&(viaPath->lastIn() < clusterMostRecentTs))
 				viaPath.zero();
 		} else if (!viaPath) {
-			peer->tryMemorizedPath(now); // periodically attempt memorized or statically defined paths, if any are known
-			return false;
-		}
 #else
 		if (!viaPath) {
+#endif
 			peer->tryMemorizedPath(now); // periodically attempt memorized or statically defined paths, if any are known
-			return false;
+			const SharedPtr<Peer> relay(RR->topology->getUpstreamPeer());
+			if ( (!relay) || (!(viaPath = relay->getBestPath(now,false))) ) {
+				if (!(viaPath = peer->getBestPath(now,true)))
+					return false;
+			}
+#ifdef ZT_ENABLE_CLUSTER
+		}
+#else
 		}
 #endif
 	} else {
 #ifdef ZT_ENABLE_CLUSTER
-		if (RR->cluster)
-			clusterMostRecentMemberId = RR->cluster->prepSendViaCluster(destination,clusterMostRecentTs,clusterPeerSecret);
 		if (clusterMostRecentMemberId < 0) {
 #else
 			requestWhois(destination);
@@ -749,15 +755,6 @@ bool Switch::_trySend(Packet &packet,bool encrypt)
 #endif
 	}
 
-	// Sanity checks
-#ifdef ZT_ENABLE_CLUSTER
-	if ((!viaPath)&&(clusterMostRecentMemberId < 0))
-		return false;
-#else
-	if (!viaPath)
-		return false;
-#endif
-
 	unsigned int chunkSize = std::min(packet.size(),(unsigned int)ZT_UDP_DEFAULT_PAYLOAD_MTU);
 	packet.setFragmented(chunkSize < packet.size());