Significant simplification to path logic.

node/Constants.hpp

@@ -289,7 +289,7 @@
 #define ZT_PEER_PING_PERIOD 60000
 
 /**
- * Paths are considered expired if they have not produced a real packet in this long
+ * Paths are considered expired if they have not sent us a real packet in this long
  */
 #define ZT_PEER_PATH_EXPIRATION ((ZT_PEER_PING_PERIOD * 4) + 3000)
 

node/IncomingPacket.cpp

@@ -1200,16 +1200,12 @@ bool IncomingPacket::_doPUSH_DIRECT_PATHS(const RuntimeEnvironment *RR,void *tPt
 
 			switch(addrType) {
 				case 4: {
-					InetAddress a(field(ptr,4),4,at<uint16_t>(ptr + 4));
-
-					bool redundant = false;
-					if ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_CLUSTER_REDIRECT) != 0) {
-						peer->setClusterOptimal(a);
-					} else {
-						redundant = peer->hasActivePathTo(now,a);
-					}
-
-					if ( ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_FORGET_PATH) == 0) && (!redundant) && (RR->node->shouldUsePathForZeroTierTraffic(tPtr,peer->address(),_path->localAddress(),a)) ) {
+					const InetAddress a(field(ptr,4),4,at<uint16_t>(ptr + 4));
+					if (
+					    ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_FORGET_PATH) == 0) && // not being told to forget
+							(!( ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_CLUSTER_REDIRECT) == 0) && (peer->hasActivePathTo(now,a)) )) && // not already known
+							(RR->node->shouldUsePathForZeroTierTraffic(tPtr,peer->address(),_path->localAddress(),a)) ) // should use path
+					{
 						if (++countPerScope[(int)a.ipScope()][0] <= ZT_PUSH_DIRECT_PATHS_MAX_PER_SCOPE_AND_FAMILY) {
 							TRACE("attempting to contact %s at pushed direct path %s",peer->address().toString().c_str(),a.toString().c_str());
 							peer->attemptToContactAt(tPtr,InetAddress(),a,now,false,0);
@@ -1219,16 +1215,12 @@ bool IncomingPacket::_doPUSH_DIRECT_PATHS(const RuntimeEnvironment *RR,void *tPt
 					}
 				}	break;
 				case 6: {
-					InetAddress a(field(ptr,16),16,at<uint16_t>(ptr + 16));
-
-					bool redundant = false;
-					if ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_CLUSTER_REDIRECT) != 0) {
-						peer->setClusterOptimal(a);
-					} else {
-						redundant = peer->hasActivePathTo(now,a);
-					}
-
-					if ( ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_FORGET_PATH) == 0) && (!redundant) && (RR->node->shouldUsePathForZeroTierTraffic(tPtr,peer->address(),_path->localAddress(),a)) ) {
+					const InetAddress a(field(ptr,16),16,at<uint16_t>(ptr + 16));
+					if (
+					    ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_FORGET_PATH) == 0) && // not being told to forget
+							(!( ((flags & ZT_PUSH_DIRECT_PATHS_FLAG_CLUSTER_REDIRECT) == 0) && (peer->hasActivePathTo(now,a)) )) && // not already known
+							(RR->node->shouldUsePathForZeroTierTraffic(tPtr,peer->address(),_path->localAddress(),a)) ) // should use path
+					{
 						if (++countPerScope[(int)a.ipScope()][1] <= ZT_PUSH_DIRECT_PATHS_MAX_PER_SCOPE_AND_FAMILY) {
 							TRACE("attempting to contact %s at pushed direct path %s",peer->address().toString().c_str(),a.toString().c_str());
 							peer->attemptToContactAt(tPtr,InetAddress(),a,now,false,0);

node/Node.cpp

@@ -407,17 +407,17 @@ ZT_PeerList *Node::peers() const
 		p->latency = pi->second->latency();
 		p->role = RR->topology->role(pi->second->identity().address());
 
-		std::vector< std::pair< SharedPtr<Path>,bool > > paths(pi->second->paths(_now));
+		std::vector< SharedPtr<Path> > paths(pi->second->paths(_now));
 		SharedPtr<Path> bestp(pi->second->getBestPath(_now,false));
 		p->pathCount = 0;
-		for(std::vector< std::pair< SharedPtr<Path>,bool > >::iterator path(paths.begin());path!=paths.end();++path) {
-			memcpy(&(p->paths[p->pathCount].address),&(path->first->address()),sizeof(struct sockaddr_storage));
-			p->paths[p->pathCount].lastSend = path->first->lastOut();
-			p->paths[p->pathCount].lastReceive = path->first->lastIn();
-			p->paths[p->pathCount].trustedPathId = RR->topology->getOutboundPathTrust(path->first->address());
-			p->paths[p->pathCount].linkQuality = (int)path->first->linkQuality();
-			p->paths[p->pathCount].expired = path->second;
-			p->paths[p->pathCount].preferred = (path->first == bestp) ? 1 : 0;
+		for(std::vector< SharedPtr<Path> >::iterator path(paths.begin());path!=paths.end();++path) {
+			memcpy(&(p->paths[p->pathCount].address),&((*path)->address()),sizeof(struct sockaddr_storage));
+			p->paths[p->pathCount].lastSend = (*path)->lastOut();
+			p->paths[p->pathCount].lastReceive = (*path)->lastIn();
+			p->paths[p->pathCount].trustedPathId = RR->topology->getOutboundPathTrust((*path)->address());
+			p->paths[p->pathCount].linkQuality = (int)(*path)->linkQuality();
+			p->paths[p->pathCount].expired = 0;
+			p->paths[p->pathCount].preferred = ((*path) == bestp) ? 1 : 0;
 			++p->pathCount;
 		}
 	}

node/Peer.cpp

@@ -27,14 +27,6 @@
 #include "Cluster.hpp"
 #include "Packet.hpp"
 
-#ifndef AF_MAX
-#if AF_INET > AF_INET6
-#define AF_MAX AF_INET
-#else
-#define AF_MAX AF_INET6
-#endif
-#endif
-
 namespace ZeroTier {
 
 Peer::Peer(const RuntimeEnvironment *renv,const Identity &myIdentity,const Identity &peerIdentity) :
@@ -51,18 +43,15 @@ Peer::Peer(const RuntimeEnvironment *renv,const Identity &myIdentity,const Ident
 	_lastComRequestSent(0),
 	_lastCredentialsReceived(0),
 	_lastTrustEstablishedPacketReceived(0),
-	_remoteClusterOptimal4(0),
 	_vProto(0),
 	_vMajor(0),
 	_vMinor(0),
 	_vRevision(0),
 	_id(peerIdentity),
-	_numPaths(0),
 	_latency(0),
 	_directPathPushCutoffCount(0),
 	_credentialsCutoffCount(0)
 {
-	memset(_remoteClusterOptimal6,0,sizeof(_remoteClusterOptimal6));
 	if (!myIdentity.agree(peerIdentity,_key,ZT_PEER_SECRET_KEY_LENGTH))
 		throw std::runtime_error("new peer identity key agreement failed");
 }
@@ -80,7 +69,7 @@ void Peer::received(
 	const uint64_t now = RR->node->now();
 
 #ifdef ZT_ENABLE_CLUSTER
-	bool suboptimalPath = false;
+	bool isClusterSuboptimalPath = false;
 	if ((RR->cluster)&&(hops == 0)) {
 		// Note: findBetterEndpoint() is first since we still want to check
 		// for a better endpoint even if we don't actually send a redirect.
@@ -146,65 +135,60 @@ void Peer::received(
 		path->updateLinkQuality((unsigned int)(packetId & 7));
 
 	if (hops == 0) {
-		bool pathIsConfirmed = false;
+		bool pathAlreadyKnown = false;
 		{
 			Mutex::Lock _l(_paths_m);
-			for(unsigned int p=0;p<_numPaths;++p) {
-				if (_paths[p].path->address() == path->address()) {
-					_paths[p].lastReceive = now;
-					_paths[p].path = path; // local address may have changed!
+			if ((path->address().ss_family == AF_INET)&&(_v4Path.p)) {
+				const struct sockaddr_in *const r = reinterpret_cast<const struct sockaddr_in *>(&(path->address()));
+				const struct sockaddr_in *const l = reinterpret_cast<const struct sockaddr_in *>(&(_v4Path.p->address()));
+				const struct sockaddr_in *const rl = reinterpret_cast<const struct sockaddr_in *>(&(path->localAddress()));
+				const struct sockaddr_in *const ll = reinterpret_cast<const struct sockaddr_in *>(&(_v4Path.p->localAddress()));
+				if ((r->sin_addr.s_addr == l->sin_addr.s_addr)&&(r->sin_port == l->sin_port)&&(rl->sin_addr.s_addr == ll->sin_addr.s_addr)&&(rl->sin_port == ll->sin_port)) {
+					_v4Path.lr = now;
 #ifdef ZT_ENABLE_CLUSTER
-					_paths[p].localClusterSuboptimal = suboptimalPath;
+					_v4Path.localClusterSuboptimal = isClusterSuboptimalPath;
 #endif
-					pathIsConfirmed = true;
-					break;
+					pathAlreadyKnown = true;
+				}
+			} else if ((path->address().ss_family == AF_INET6)&&(_v6Path.p)) {
+				const struct sockaddr_in6 *const r = reinterpret_cast<const struct sockaddr_in6 *>(&(path->address()));
+				const struct sockaddr_in6 *const l = reinterpret_cast<const struct sockaddr_in6 *>(&(_v6Path.p->address()));
+				const struct sockaddr_in6 *const rl = reinterpret_cast<const struct sockaddr_in6 *>(&(path->localAddress()));
+				const struct sockaddr_in6 *const ll = reinterpret_cast<const struct sockaddr_in6 *>(&(_v6Path.p->localAddress()));
+				if ((!memcmp(r->sin6_addr.s6_addr,l->sin6_addr.s6_addr,16))&&(r->sin6_port == l->sin6_port)&&(!memcmp(rl->sin6_addr.s6_addr,ll->sin6_addr.s6_addr,16))&&(rl->sin6_port == ll->sin6_port)) {
+					_v6Path.lr = now;
+#ifdef ZT_ENABLE_CLUSTER
+					_v6Path.localClusterSuboptimal = isClusterSuboptimalPath;
+#endif
+					pathAlreadyKnown = true;
 				}
 			}
 		}
 
-		if ( (!pathIsConfirmed) && (RR->node->shouldUsePathForZeroTierTraffic(tPtr,_id.address(),path->localAddress(),path->address())) ) {
+		if ( (!pathAlreadyKnown) && (RR->node->shouldUsePathForZeroTierTraffic(tPtr,_id.address(),path->localAddress(),path->address())) ) {
 			if (verb == Packet::VERB_OK) {
 				Mutex::Lock _l(_paths_m);
-
-				// Since this is a new path, figure out where to put it (possibly replacing an old/dead one)
-				unsigned int slot;
-				if (_numPaths < ZT_MAX_PEER_NETWORK_PATHS) {
-					slot = _numPaths++;
-				} else {
-					// First try to replace the worst within the same address family, if possible
-					int worstSlot = -1;
-					uint64_t worstScore = 0xffffffffffffffffULL;
-					for(unsigned int p=0;p<_numPaths;++p) {
-						if (_paths[p].path->address().ss_family == path->address().ss_family) {
-							const uint64_t s = _pathScore(p,now);
-							if (s < worstScore) {
-								worstScore = s;
-								worstSlot = (int)p;
-							}
-						}
-					}
-					if (worstSlot >= 0) {
-						slot = (unsigned int)worstSlot;
-					} else {
-						// If we can't find one with the same family, replace the worst of any family
-						slot = ZT_MAX_PEER_NETWORK_PATHS - 1;
-						for(unsigned int p=0;p<_numPaths;++p) {
-							const uint64_t s = _pathScore(p,now);
-							if (s < worstScore) {
-								worstScore = s;
-								slot = p;
-							}
-						}
+				if (path->address().ss_family == AF_INET) {
+					if ((!_v4Path.p)||(!_v4Path.p->alive(now))||(path->preferenceRank() >= _v4Path.p->preferenceRank())) {
+						_v4Path.lr = now;
+						_v4Path.p = path;
+#ifdef ZT_ENABLE_CLUSTER
+						_v4Path.localClusterSuboptimal = isClusterSuboptimalPath;
+						if (RR->cluster)
+							RR->cluster->broadcastHavePeer(_id);
+#endif
 					}
-				}
-
-				_paths[slot].lastReceive = now;
-				_paths[slot].path = path;
+				} else if (path->address().ss_family == AF_INET6) {
+					if ((!_v6Path.p)||(!_v6Path.p->alive(now))||(path->preferenceRank() >= _v6Path.p->preferenceRank())) {
+						_v6Path.lr = now;
+						_v6Path.p = path;
 #ifdef ZT_ENABLE_CLUSTER
-				_paths[slot].localClusterSuboptimal = suboptimalPath;
-				if (RR->cluster)
-					RR->cluster->broadcastHavePeer(_id);
+						_v6Path.localClusterSuboptimal = isClusterSuboptimalPath;
+						if (RR->cluster)
+							RR->cluster->broadcastHavePeer(_id);
 #endif
+					}
+				}
 			} else {
 				TRACE("got %s via unknown path %s(%s), confirming...",Packet::verbString(verb),_id.address().toString().c_str(),path->address().toString().c_str());
 				attemptToContactAt(tPtr,path->localAddress(),path->address(),now,true,path->nextOutgoingCounter());
@@ -214,10 +198,10 @@ void Peer::received(
 	} else if (this->trustEstablished(now)) {
 		// Send PUSH_DIRECT_PATHS if hops>0 (relayed) and we have a trust relationship (common network membership)
 #ifdef ZT_ENABLE_CLUSTER
-			// Cluster mode disables normal PUSH_DIRECT_PATHS in favor of cluster-based peer redirection
-			const bool haveCluster = (RR->cluster);
+		// Cluster mode disables normal PUSH_DIRECT_PATHS in favor of cluster-based peer redirection
+		const bool haveCluster = (RR->cluster);
 #else
-			const bool haveCluster = false;
+		const bool haveCluster = false;
 #endif
 		if ( ((now - _lastDirectPathPushSent) >= ZT_DIRECT_PATH_PUSH_INTERVAL) && (!haveCluster) ) {
 			_lastDirectPathPushSent = now;
@@ -290,60 +274,50 @@ void Peer::received(
 	}
 }
 
-bool Peer::hasActivePathTo(uint64_t now,const InetAddress &addr) const
-{
-	Mutex::Lock _l(_paths_m);
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( (_paths[p].path->address() == addr) && ((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION) && (_paths[p].path->alive(now)) )
-			return true; 
-	}
-	return false;
-}
-
-bool Peer::sendDirect(void *tPtr,const void *data,unsigned int len,uint64_t now,bool forceEvenIfDead)
+bool Peer::sendDirect(void *tPtr,const void *data,unsigned int len,uint64_t now,bool force)
 {
 	Mutex::Lock _l(_paths_m);
 
-	int bestp = -1;
-	uint64_t best = 0ULL;
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( ((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION) && (_paths[p].path->alive(now)||(forceEvenIfDead)) ) {
-			const uint64_t s = _pathScore(p,now);
-			if (s >= best) {
-				best = s;
-				bestp = (int)p;
-			}
+	uint64_t v6lr = 0;
+	if ( ((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION) && (_v6Path.p) )
+		v6lr = _v6Path.p->lastIn();
+	uint64_t v4lr = 0;
+	if ( ((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION) && (_v4Path.p) )
+		v4lr = _v4Path.p->lastIn();
+
+	if ( (v6lr > v4lr) && ((now - v6lr) < ZT_PATH_ALIVE_TIMEOUT) ) {
+		return _v6Path.p->send(RR,tPtr,data,len,now);
+	} else if ((now - v4lr) < ZT_PATH_ALIVE_TIMEOUT) {
+		return _v4Path.p->send(RR,tPtr,data,len,now);
+	} else if (force) {
+		if (v6lr > v4lr) {
+			return _v6Path.p->send(RR,tPtr,data,len,now);
+		} else if (v4lr) {
+			return _v4Path.p->send(RR,tPtr,data,len,now);
 		}
 	}
 
-	if (bestp >= 0) {
-		return _paths[bestp].path->send(RR,tPtr,data,len,now);
-	} else {
-		return false;
-	}
+	return false;
 }
 
 SharedPtr<Path> Peer::getBestPath(uint64_t now,bool includeExpired)
 {
 	Mutex::Lock _l(_paths_m);
 
-	int bestp = -1;
-	uint64_t best = 0ULL;
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( ((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION) || (includeExpired) ) {
-			const uint64_t s = _pathScore(p,now);
-			if (s >= best) {
-				best = s;
-				bestp = (int)p;
-			}
-		}
+	uint64_t v6lr = 0;
+	if ( ( includeExpired || ((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION) ) && (_v6Path.p) )
+		v6lr = _v6Path.p->lastIn();
+	uint64_t v4lr = 0;
+	if ( ( includeExpired || ((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION) ) && (_v4Path.p) )
+		v4lr = _v4Path.p->lastIn();
+
+	if (v6lr > v4lr) {
+		return _v6Path.p;
+	} else if (v4lr) {
+		return _v4Path.p;
 	}
 
-	if (bestp >= 0) {
-		return _paths[bestp].path;
-	} else {
-		return SharedPtr<Path>();
-	}
+	return SharedPtr<Path>();
 }
 
 void Peer::sendHELLO(void *tPtr,const InetAddress &localAddr,const InetAddress &atAddress,uint64_t now,unsigned int counter)
@@ -420,79 +394,44 @@ bool Peer::doPingAndKeepalive(void *tPtr,uint64_t now,int inetAddressFamily)
 {
 	Mutex::Lock _l(_paths_m);
 
-	int bestp = -1;
-	uint64_t best = 0ULL;
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( ((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION) && ((inetAddressFamily < 0)||((int)_paths[p].path->address().ss_family == inetAddressFamily)) ) {
-			const uint64_t s = _pathScore(p,now);
-			if (s >= best) {
-				best = s;
-				bestp = (int)p;
+	if (inetAddressFamily < 0) {
+		uint64_t v6lr = 0;
+		if ( ((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION) && (_v6Path.p) )
+			v6lr = _v6Path.p->lastIn();
+		uint64_t v4lr = 0;
+		if ( ((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION) && (_v4Path.p) )
+			v4lr = _v4Path.p->lastIn();
+
+		if (v6lr > v4lr) {
+			if ( ((now - _v6Path.lr) >= ZT_PEER_PING_PERIOD) || (_v6Path.p->needsHeartbeat(now)) ) {
+				attemptToContactAt(tPtr,_v6Path.p->localAddress(),_v6Path.p->address(),now,false,_v6Path.p->nextOutgoingCounter());
+				_v6Path.p->sent(now);
+				return true;
+			}
+		} else if (v4lr) {
+			if ( ((now - _v4Path.lr) >= ZT_PEER_PING_PERIOD) || (_v4Path.p->needsHeartbeat(now)) ) {
+				attemptToContactAt(tPtr,_v4Path.p->localAddress(),_v4Path.p->address(),now,false,_v4Path.p->nextOutgoingCounter());
+				_v4Path.p->sent(now);
+				return true;
 			}
 		}
-	}
-
-	if (bestp >= 0) {
-		if ( ((now - _paths[bestp].lastReceive) >= ZT_PEER_PING_PERIOD) || (_paths[bestp].path->needsHeartbeat(now)) ) {
-			attemptToContactAt(tPtr,_paths[bestp].path->localAddress(),_paths[bestp].path->address(),now,false,_paths[bestp].path->nextOutgoingCounter());
-			_paths[bestp].path->sent(now);
-		}
-		return true;
 	} else {
-		return false;
-	}
-}
-
-bool Peer::hasActiveDirectPath(uint64_t now) const
-{
-	Mutex::Lock _l(_paths_m);
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if (((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION)&&(_paths[p].path->alive(now)))
-			return true;
-	}
-	return false;
-}
-
-void Peer::resetWithinScope(void *tPtr,InetAddress::IpScope scope,int inetAddressFamily,uint64_t now)
-{
-	Mutex::Lock _l(_paths_m);
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( (_paths[p].path->address().ss_family == inetAddressFamily) && (_paths[p].path->address().ipScope() == scope) ) {
-			attemptToContactAt(tPtr,_paths[p].path->localAddress(),_paths[p].path->address(),now,false,_paths[p].path->nextOutgoingCounter());
-			_paths[p].path->sent(now);
-			_paths[p].lastReceive = 0; // path will not be used unless it speaks again
-		}
-	}
-}
-
-void Peer::getRendezvousAddresses(uint64_t now,InetAddress &v4,InetAddress &v6) const
-{
-	Mutex::Lock _l(_paths_m);
-
-	int bestp4 = -1,bestp6 = -1;
-	uint64_t best4 = 0ULL,best6 = 0ULL;
-	for(unsigned int p=0;p<_numPaths;++p) {
-		if ( ((now - _paths[p].lastReceive) <= ZT_PEER_PATH_EXPIRATION) && (_paths[p].path->alive(now)) ) {
-			if (_paths[p].path->address().ss_family == AF_INET) {
-				const uint64_t s = _pathScore(p,now);
-				if (s >= best4) {
-					best4 = s;
-					bestp4 = (int)p;
-				}
-			} else if (_paths[p].path->address().ss_family == AF_INET6) {
-				const uint64_t s = _pathScore(p,now);
-				if (s >= best6) {
-					best6 = s;
-					bestp6 = (int)p;
-				}
+		if ( (inetAddressFamily == AF_INET) && ((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION) ) {
+			if ( ((now - _v4Path.lr) >= ZT_PEER_PING_PERIOD) || (_v4Path.p->needsHeartbeat(now)) ) {
+				attemptToContactAt(tPtr,_v4Path.p->localAddress(),_v4Path.p->address(),now,false,_v4Path.p->nextOutgoingCounter());
+				_v4Path.p->sent(now);
+				return true;
+			}
+		} else if ( (inetAddressFamily == AF_INET6) && ((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION) ) {
+			if ( ((now - _v6Path.lr) >= ZT_PEER_PING_PERIOD) || (_v6Path.p->needsHeartbeat(now)) ) {
+				attemptToContactAt(tPtr,_v6Path.p->localAddress(),_v6Path.p->address(),now,false,_v6Path.p->nextOutgoingCounter());
+				_v6Path.p->sent(now);
+				return true;
 			}
 		}
 	}
 
-	if (bestp4 >= 0)
-		v4 = _paths[bestp4].path->address();
-	if (bestp6 >= 0)
-		v6 = _paths[bestp6].path->address();
+	return false;
 }
 
 } // namespace ZeroTier

node/Peer.hpp

@@ -108,20 +108,10 @@ public:
 	 * @param addr Remote address
 	 * @return True if we have an active path to this destination
 	 */
-	bool hasActivePathTo(uint64_t now,const InetAddress &addr) const;
-
-	/**
-	 * Set which known path for an address family is optimal
-	 *
-	 * @param addr Address to make exclusive
-	 */
-	inline void setClusterOptimal(const InetAddress &addr)
+	inline bool hasActivePathTo(uint64_t now,const InetAddress &addr) const
 	{
-		if (addr.ss_family == AF_INET) {
-			_remoteClusterOptimal4 = (uint32_t)reinterpret_cast<const struct sockaddr_in *>(&addr)->sin_addr.s_addr;
-		} else if (addr.ss_family == AF_INET6) {
-			memcpy(_remoteClusterOptimal6,reinterpret_cast<const struct sockaddr_in6 *>(&addr)->sin6_addr.s6_addr,16);
-		}
+		Mutex::Lock _l(_paths_m);
+		return ( ((addr.ss_family == AF_INET)&&(_v4Path.p)&&(_v4Path.p->address() == addr)&&(_v4Path.p->alive(now))) || ((addr.ss_family == AF_INET6)&&(_v6Path.p)&&(_v6Path.p->address() == addr)&&(_v6Path.p->alive(now))) );
 	}
 
 	/**
@@ -131,14 +121,17 @@ public:
 	 * @param data Packet data
 	 * @param len Packet length
 	 * @param now Current time
-	 * @param forceEvenIfDead If true, send even if the path is not 'alive'
+	 * @param force If true, send even if path is not alive
 	 * @return True if we actually sent something
 	 */
-	bool sendDirect(void *tPtr,const void *data,unsigned int len,uint64_t now,bool forceEvenIfDead);
+	bool sendDirect(void *tPtr,const void *data,unsigned int len,uint64_t now,bool force);
 
 	/**
 	 * Get the best current direct path
 	 *
+	 * This does not check Path::alive(), but does return the most recently
+	 * active path and does check expiration (which is a longer timeout).
+	 *
 	 * @param now Current time
 	 * @param includeExpired If true, include even expired paths
 	 * @return Best current path or NULL if none
@@ -192,12 +185,6 @@ public:
 	 */
 	bool doPingAndKeepalive(void *tPtr,uint64_t now,int inetAddressFamily);
 
-	/**
-	 * @param now Current time
-	 * @return True if this peer has at least one active and alive direct path
-	 */
-	bool hasActiveDirectPath(uint64_t now) const;
-
 	/**
 	 * Reset paths within a given IP scope and address family
 	 *
@@ -209,30 +196,48 @@ public:
 	 * @param inetAddressFamily Family e.g. AF_INET
 	 * @param now Current time
 	 */
-	void resetWithinScope(void *tPtr,InetAddress::IpScope scope,int inetAddressFamily,uint64_t now);
+	inline void resetWithinScope(void *tPtr,InetAddress::IpScope scope,int inetAddressFamily,uint64_t now)
+	{
+		Mutex::Lock _l(_paths_m);
+		if ((inetAddressFamily == AF_INET)&&(_v4Path.lr)&&(_v4Path.p->address().ipScope() == scope)) {
+			attemptToContactAt(tPtr,_v4Path.p->localAddress(),_v4Path.p->address(),now,false,_v4Path.p->nextOutgoingCounter());
+			_v4Path.p->sent(now);
+			_v4Path.lr = 0; // path will not be used unless it speaks again
+		} else if ((inetAddressFamily == AF_INET6)&&(_v6Path.lr)&&(_v6Path.p->address().ipScope() == scope)) {
+			attemptToContactAt(tPtr,_v6Path.p->localAddress(),_v6Path.p->address(),now,false,_v6Path.p->nextOutgoingCounter());
+			_v6Path.p->sent(now);
+			_v6Path.lr = 0; // path will not be used unless it speaks again
+		}
+	}
 
 	/**
-	 * Get most recently active path addresses for IPv4 and/or IPv6
-	 *
-	 * Note that v4 and v6 are not modified if they are not found, so
-	 * initialize these to a NULL address to be able to check.
+	 * Fill parameters with V4 and V6 addresses if known and alive
 	 *
 	 * @param now Current time
 	 * @param v4 Result parameter to receive active IPv4 address, if any
 	 * @param v6 Result parameter to receive active IPv6 address, if any
 	 */
-	void getRendezvousAddresses(uint64_t now,InetAddress &v4,InetAddress &v6) const;
+	inline void getRendezvousAddresses(uint64_t now,InetAddress &v4,InetAddress &v6) const
+	{
+		Mutex::Lock _l(_paths_m);
+		if (((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION)&&(_v4Path.p->alive(now)))
+			v4 = _v4Path.p->address();
+		if (((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION)&&(_v6Path.p->alive(now)))
+			v6 = _v6Path.p->address();
+	}
 
 	/**
 	 * @param now Current time
-	 * @return All known direct paths to this peer and whether they are expired (true == expired)
+	 * @return All known paths to this peer
 	 */
-	inline std::vector< std::pair< SharedPtr<Path>,bool > > paths(const uint64_t now) const
+	inline std::vector< SharedPtr<Path> > paths(const uint64_t now) const
 	{
-		std::vector< std::pair< SharedPtr<Path>,bool > > pp;
+		std::vector< SharedPtr<Path> > pp;
 		Mutex::Lock _l(_paths_m);
-		for(unsigned int p=0,np=_numPaths;p<np;++p)
-			pp.push_back(std::pair< SharedPtr<Path>,bool >(_paths[p].path,(now - _paths[p].lastReceive) > ZT_PEER_PATH_EXPIRATION));
+		if (((now - _v4Path.lr) < ZT_PEER_PATH_EXPIRATION)&&(_v4Path.p->alive(now)))
+			pp.push_back(_v4Path.p);
+		if (((now - _v6Path.lr) < ZT_PEER_PATH_EXPIRATION)&&(_v6Path.p->alive(now)))
+			pp.push_back(_v6Path.p);
 		return pp;
 	}
 
@@ -424,32 +429,19 @@ public:
 	}
 
 private:
-	inline uint64_t _pathScore(const unsigned int p,const uint64_t now) const
+	struct _PeerPath
 	{
-		uint64_t s = ZT_PEER_PING_PERIOD + _paths[p].lastReceive + (uint64_t)(_paths[p].path->preferenceRank() * (ZT_PEER_PING_PERIOD / ZT_PATH_MAX_PREFERENCE_RANK));
-
-		if (_paths[p].path->address().ss_family == AF_INET) {
-			s +=  (uint64_t)(ZT_PEER_PING_PERIOD * (unsigned long)(reinterpret_cast<const struct sockaddr_in *>(&(_paths[p].path->address()))->sin_addr.s_addr == _remoteClusterOptimal4));
-		} else if (_paths[p].path->address().ss_family == AF_INET6) {
-			uint64_t clusterWeight = ZT_PEER_PING_PERIOD;
-			const uint8_t *a = reinterpret_cast<const uint8_t *>(reinterpret_cast<const struct sockaddr_in6 *>(&(_paths[p].path->address()))->sin6_addr.s6_addr);
-			for(long i=0;i<16;++i) {
-				if (a[i] != _remoteClusterOptimal6[i]) {
-					clusterWeight = 0;
-					break;
-				}
-			}
-			s += clusterWeight;
-		}
-
-		s += (ZT_PEER_PING_PERIOD / 2) * (uint64_t)_paths[p].path->alive(now);
-
 #ifdef ZT_ENABLE_CLUSTER
-		s -= ZT_PEER_PING_PERIOD * (uint64_t)_paths[p].localClusterSuboptimal;
+		_PeerPath() : lr(0),p(),localClusterSuboptimal(false) {}
+#else
+		_PeerPath() : lr(0),p() {}
 #endif
-
-		return s;
-	}
+		uint64_t lr; // time of last valid ZeroTier packet
+		SharedPtr<Path> p;
+#ifdef ZT_ENABLE_CLUSTER
+		bool localClusterSuboptimal; // true if our cluster has determined that we should not be serving this peer
+#endif
+	};
 
 	uint8_t _key[ZT_PEER_SECRET_KEY_LENGTH];
 
@@ -468,26 +460,17 @@ private:
 	uint64_t _lastCredentialsReceived;
 	uint64_t _lastTrustEstablishedPacketReceived;
 
-	uint8_t _remoteClusterOptimal6[16];
-	uint32_t _remoteClusterOptimal4;
-
 	uint16_t _vProto;
 	uint16_t _vMajor;
 	uint16_t _vMinor;
 	uint16_t _vRevision;
 
-	Identity _id;
-
-	struct {
-		uint64_t lastReceive;
-		SharedPtr<Path> path;
-#ifdef ZT_ENABLE_CLUSTER
-		bool localClusterSuboptimal;
-#endif
-	} _paths[ZT_MAX_PEER_NETWORK_PATHS];
+	_PeerPath _v4Path; // IPv4 direct path
+	_PeerPath _v6Path; // IPv6 direct path
 	Mutex _paths_m;
 
-	unsigned int _numPaths;
+	Identity _id;
+
 	unsigned int _latency;
 	unsigned int _directPathPushCutoffCount;
 	unsigned int _credentialsCutoffCount;

node/Topology.hpp

@@ -314,7 +314,9 @@ public:
 		Address *a = (Address *)0;
 		SharedPtr<Peer> *p = (SharedPtr<Peer> *)0;
 		while (i.next(a,p)) {
-			cnt += (unsigned long)((*p)->hasActiveDirectPath(now));
+			const SharedPtr<Path> pp((*p)->getBestPath(now,false));
+			if ((pp)&&(pp->alive(now)))
+				++cnt;
 		}
 		return cnt;
 	}