Keep track of basic aliveness for peers regardless if direct or indirect connectivity and use this for multicast propagation. Also consolidate adding of active bridges via the same functor as regular multicast next hops.

node/Multicaster.hpp

@@ -40,6 +40,7 @@
 #include "Constants.hpp"
 #include "Mutex.hpp"
 #include "MulticastGroup.hpp"
+#include "Topology.hpp"
 #include "Address.hpp"
 #include "Buffer.hpp"
 
@@ -112,6 +113,7 @@ public:
 	 * @param nwid Network ID
 	 * @param mg Multicast group
 	 * @param nextHopFunc Function to call for each address, search stops if it returns false
+	 * @tparam F Function to receive each next hop address
 	 */
 	template<typename F>
 	inline void getNextHops(uint64_t nwid,const MulticastGroup &mg,F nextHopFunc)
@@ -151,20 +153,40 @@ public:
 		 * @param origin Originating address
 		 * @param prefixBits Number of bits in propagation restriction prefix
 		 * @param prefix Propagation restrition prefix
+		 * @param topology Topology database
+		 * @param now Current time
 		 */
-		AddToPropagationQueue(unsigned char **ptr,unsigned char *end,unsigned char *bloom,uint16_t bloomNonce,const Address &origin,unsigned int prefixBits,uint64_t prefix)
-			throw() :
+		AddToPropagationQueue(
+			unsigned char **ptr,
+			unsigned char *end,
+			unsigned char *bloom,
+			uint16_t bloomNonce,
+			const Address &origin,
+			unsigned int prefixBits,
+			uint64_t prefix,
+			const Topology *topology,
+			uint64_t now)
+		throw() :
 			_origin(origin),
 			_bloomNonce((uint64_t)bloomNonce),
 			_prefix(prefix),
+			_now(now),
 			_ptr(ptr),
 			_end(end),
 			_bloom(bloom),
+			_topology(topology),
 			_prefixBits(prefixBits) {}
 
+		/**
+		 * @param a Address to (possibly) add
+		 * @return True if FIFO still contains room for more possible addresses
+		 */
 		inline bool operator()(const Address &a)
 			throw()
 		{
+			if (*_ptr >= _end)
+				return false;
+
 			// Exclude original sender -- obviously they've already seen it
 			if (a == _origin)
 				return true;
@@ -173,27 +195,36 @@ public:
 			if (!a.withinMulticastPropagationPrefix(_prefix,_prefixBits))
 				return true;
 
-			// Exclude addresses remembered in bloom filter -- or else remember them
+			// Exclude addresses remembered in bloom filter
 			uint64_t aint = a.toInt() + _bloomNonce;
 			const unsigned int bit = (unsigned int)(aint ^ (aint >> 13) ^ (aint >> 26) ^ (aint >> 39)) & 0x1fff;
 			unsigned char *const bbyte = _bloom + (bit >> 3); // note: bloom filter size == 1024 is hard-coded here
 			const unsigned char bmask = 1 << (bit & 7);
 			if ((*bbyte & bmask))
+				return true; // address already visited
+
+			// Exclude peers that don't appear to be online
+			SharedPtr<Peer> p(_topology->getPeer(a));
+			if ((!p)||(!p->alive(_now)))
 				return true;
-			else *bbyte |= bmask;
+
+			// Remember address in bloom filter
+			*bbyte |= bmask;
 
 			a.copyTo(*_ptr,ZT_ADDRESS_LENGTH);
-			return ((*_ptr += ZT_ADDRESS_LENGTH) != _end);
+			return ((*_ptr += ZT_ADDRESS_LENGTH) < _end);
 		}
 
 	private:
 		const Address _origin;
 		const uint64_t _bloomNonce;
 		const uint64_t _prefix;
+		const uint64_t _now;
 		unsigned char **const _ptr;
 		unsigned char *const _end;
 		unsigned char *const _bloom;
-		unsigned int _prefixBits;
+		const Topology *const _topology;
+		const unsigned int _prefixBits;
 	};
 
 private: