Almost done... very few std::map<>s remaining in any spot that matters.

node/Hashtable.hpp

@@ -39,8 +39,9 @@ namespace ZeroTier {
  * A minimal hash table implementation for the ZeroTier core
  *
  * This is not a drop-in replacement for STL containers, and has several
- * limitations. It's designed to be small and fast for use in the
- * ZeroTier core.
+ * limitations. Keys can be uint64_t or an object, and if the latter they
+ * must implement a method called hashCode() that returns an unsigned long
+ * value that is evenly distributed.
  */
 template<typename K,typename V>
 class Hashtable

node/Switch.cpp

@@ -309,31 +309,18 @@ bool Switch::unite(const Address &p1,const Address &p2,bool force)
 
 	const uint64_t now = RR->node->now();
 
-	std::pair<InetAddress,InetAddress> cg(Peer::findCommonGround(*p1p,*p2p,now));
-	if (!(cg.first))
-		return false;
-
-	if (cg.first.ipScope() != cg.second.ipScope())
-		return false;
-
-	// Addresses are sorted in key for last unite attempt map for order
-	// invariant lookup: (p1,p2) == (p2,p1)
-	Array<Address,2> uniteKey;
-	if (p1 >= p2) {
-		uniteKey[0] = p2;
-		uniteKey[1] = p1;
-	} else {
-		uniteKey[0] = p1;
-		uniteKey[1] = p2;
-	}
 	{
 		Mutex::Lock _l(_lastUniteAttempt_m);
-		std::map< Array< Address,2 >,uint64_t >::const_iterator e(_lastUniteAttempt.find(uniteKey));
-		if ((!force)&&(e != _lastUniteAttempt.end())&&((now - e->second) < ZT_MIN_UNITE_INTERVAL))
+		uint64_t &luts = _lastUniteAttempt[_LastUniteKey(p1,p2)];
+		if (((now - luts) < ZT_MIN_UNITE_INTERVAL)&&(!force))
 			return false;
-		else _lastUniteAttempt[uniteKey] = now;
+		luts = now;
 	}
 
+	std::pair<InetAddress,InetAddress> cg(Peer::findCommonGround(*p1p,*p2p,now));
+	if ((!(cg.first))||(cg.first.ipScope() != cg.second.ipScope()))
+		return false;
+
 	TRACE("unite: %s(%s) <> %s(%s)",p1.toString().c_str(),cg.second.toString().c_str(),p2.toString().c_str(),cg.first.toString().c_str());
 
 	/* Tell P1 where to find P2 and vice versa, sending the packets to P1 and
@@ -543,6 +530,17 @@ unsigned long Switch::doTimerTasks(uint64_t now)
 		}
 	}
 
+	{	// Remove really old last unite attempt entries to keep table size controlled
+		Mutex::Lock _l(_lastUniteAttempt_m);
+		Hashtable< _LastUniteKey,uint64_t >::Iterator i(_lastUniteAttempt);
+		_LastUniteKey *k = (_LastUniteKey *)0;
+		uint64_t *v = (uint64_t *)0;
+		while (i.next(k,v)) {
+			if ((now - *v) >= (ZT_MIN_UNITE_INTERVAL * 16))
+				_lastUniteAttempt.erase(*k);
+		}
+	}
+
 	return nextDelay;
 }
 

node/Switch.hpp

@@ -235,7 +235,24 @@ private:
 	Mutex _txQueue_m;
 
 	// Tracks sending of VERB_RENDEZVOUS to relaying peers
-	std::map< Array< Address,2 >,uint64_t > _lastUniteAttempt; // key is always sorted in ascending order, for set-like behavior
+	struct _LastUniteKey
+	{
+		_LastUniteKey() : x(0),y(0) {}
+		_LastUniteKey(const Address &a1,const Address &a2)
+		{
+			if (a1 > a2) {
+				x = a2.toInt();
+				y = a1.toInt();
+			} else {
+				x = a1.toInt();
+				y = a2.toInt();
+			}
+		}
+		inline unsigned long hashCode() const throw() { return ((unsigned long)x ^ (unsigned long)y); }
+		inline bool operator==(const _LastUniteKey &k) const throw() { return ((x == k.x)&&(y == k.y)); }
+		uint64_t x,y;
+	};
+	Hashtable< _LastUniteKey,uint64_t > _lastUniteAttempt; // key is always sorted in ascending order, for set-like behavior
 	Mutex _lastUniteAttempt_m;
 
 	// Active attempts to contact remote peers, including state of multi-phase NAT traversal