limit tunnel length to 8 hops

libi2pd/Tunnel.cpp

@@ -42,8 +42,8 @@ namespace tunnel
 	void Tunnel::Build (uint32_t replyMsgID, std::shared_ptr<OutboundTunnel> outboundTunnel)
 	{
 		auto numHops = m_Config->GetNumHops ();
-		int numRecords = numHops <= STANDARD_NUM_RECORDS ? STANDARD_NUM_RECORDS : numHops;
-		auto msg = NewI2NPShortMessage ();
+		int numRecords = numHops <= STANDARD_NUM_RECORDS ? STANDARD_NUM_RECORDS : MAX_NUM_RECORDS;
+		auto msg = numRecords <= STANDARD_NUM_RECORDS ? NewI2NPShortMessage () : NewI2NPMessage ();
 		*msg->GetPayload () = numRecords;
 		msg->len += numRecords*TUNNEL_BUILD_RECORD_SIZE + 1;
 		// shuffle records

libi2pd/Tunnel.h

@@ -37,7 +37,8 @@ namespace tunnel
 	const int TUNNEL_RECREATION_THRESHOLD = 90; // 1.5 minutes
 	const int TUNNEL_CREATION_TIMEOUT = 30; // 30 seconds
 	const int STANDARD_NUM_RECORDS = 4; // in VariableTunnelBuild message
-
+	const int MAX_NUM_RECORDS = 8;
+	
 	enum TunnelState
 	{
 		eTunnelStatePending,