Relay txes through MN network faster than through regular nodes (#2397)

* Half the delay for relaying txes to Masternode outbound peers comparing to regular ones

* No delay for relaying txes if our node is a Masternode

src/net_processing.cpp

@@ -3343,11 +3343,14 @@ bool SendMessages(CNode* pto, CConnman& connman, const std::atomic<bool>& interr
             pto->vInventoryBlockToSend.clear();
 
             // Check whether periodic sends should happen
-            bool fSendTrickle = pto->fWhitelisted;
+            // Note: If this node is running in a Masternode mode, it makes no sense to delay outgoing txes
+            // because we never produce any txes ourselves i.e. no privacy is lost in this case.
+            bool fSendTrickle = pto->fWhitelisted || fMasternodeMode;
             if (pto->nNextInvSend < nNow) {
                 fSendTrickle = true;
-                // Use half the delay for outbound peers, as there is less privacy concern for them.
-                pto->nNextInvSend = PoissonNextSend(nNow, INVENTORY_BROADCAST_INTERVAL >> !pto->fInbound);
+                // Use half the delay for regular outbound peers, as there is less privacy concern for them,
+                // and quarter the delay for Masternode outbound peers, as there is even less privacy concern in this case.
+                pto->nNextInvSend = PoissonNextSend(nNow, INVENTORY_BROADCAST_INTERVAL >> !pto->fInbound >> pto->fMasternode);
             }
 
             // Time to send but the peer has requested we not relay transactions.

src/validation.h

@@ -112,7 +112,8 @@ static const unsigned int AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24 * 24 * 60;
 /** Average delay between peer address broadcasts in seconds. */
 static const unsigned int AVG_ADDRESS_BROADCAST_INTERVAL = 30;
 /** Average delay between trickled inventory transmissions in seconds.
- *  Blocks and whitelisted receivers bypass this, outbound peers get half this delay. */
+ *  Blocks and whitelisted receivers bypass this, regular outbound peers get half this delay,
+ *  Masternode outbound peers get quarter this delay. */
 static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
 /** Maximum number of inventory items to send per transmission.
  *  Limits the impact of low-fee transaction floods.