[p2p] Reattempt initial send of unbroadcast transactions

Every 10-15 minutes, the scheduler kicks off a job that queues unbroadcast
transactions onto each node.

Author: amitiuttarwar

src/net_processing.cpp

@@ -779,6 +779,19 @@ void PeerLogicValidation::InitializeNode(CNode *pnode) {
         PushNodeVersion(pnode, connman, GetTime());
 }
 
+void PeerLogicValidation::ReattemptInitialBroadcast(CScheduler& scheduler) const
+{
+    std::set<uint256> unbroadcast_txids = m_mempool.GetUnbroadcastTxs();
+
+    for (const uint256& txid : unbroadcast_txids) {
+        RelayTransaction(txid, *connman);
+    }
+
+    // schedule next run for 10-15 minutes in the future
+    const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5});
+    scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
+}
+
 void PeerLogicValidation::FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTime) {
     fUpdateConnectionTime = false;
     LOCK(cs_main);
@@ -1128,6 +1141,10 @@ PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn, BanMan* banman, CS
     // timer.
     static_assert(EXTRA_PEER_CHECK_INTERVAL < STALE_CHECK_INTERVAL, "peer eviction timer should be less than stale tip check timer");
     scheduler.scheduleEvery([this, consensusParams] { this->CheckForStaleTipAndEvictPeers(consensusParams); }, std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL});
+
+    // schedule next run for 10-15 minutes in the future
+    const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5});
+    scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
 }
 
 /**

src/net_processing.h

@@ -75,6 +75,8 @@ class PeerLogicValidation final : public CValidationInterface, public NetEventsI
     void CheckForStaleTipAndEvictPeers(const Consensus::Params &consensusParams);
     /** If we have extra outbound peers, try to disconnect the one with the oldest block announcement */
     void EvictExtraOutboundPeers(int64_t time_in_seconds) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
+    /** Retrieve unbroadcast transactions from the mempool and reattempt sending to peers */
+    void ReattemptInitialBroadcast(CScheduler& scheduler) const;
 
 private:
     int64_t m_stale_tip_check_time; //!< Next time to check for stale tip