Refactor ProcessGetData in anticipation of avoiding cs_main for ABC

src/net_processing.cpp

@@ -1038,29 +1038,11 @@ static void RelayAddress(const CAddress& addr, bool fReachable, CConnman* connma
     connman->ForEachNodeThen(std::move(sortfunc), std::move(pushfunc));
 }
 
-void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParams, CConnman* connman, const std::atomic<bool>& interruptMsgProc)
+void static ProcessGetBlockData(CNode* pfrom, const Consensus::Params& consensusParams, const CInv& inv, CConnman* connman, const std::atomic<bool>& interruptMsgProc)
 {
-    std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
-    std::vector<CInv> vNotFound;
-    const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     LOCK(cs_main);
 
-    while (it != pfrom->vRecvGetData.end()) {
-        // Don't bother if send buffer is too full to respond anyway
-        if (pfrom->fPauseSend)
-            break;
-
-        const CInv &inv = *it;
-        {
-            if (interruptMsgProc)
-                return;
-
-            it++;
-
-            if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK)
-            {
     bool send = false;
-                BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
     std::shared_ptr<const CBlock> a_recent_block;
     std::shared_ptr<const CBlockHeaderAndShortTxIDs> a_recent_compact_block;
     bool fWitnessesPresentInARecentCompactBlock;
@@ -1070,6 +1052,9 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
         a_recent_compact_block = most_recent_compact_block;
         fWitnessesPresentInARecentCompactBlock = fWitnessesPresentInMostRecentCompactBlock;
     }
+
+    {
+        BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
         if (mi != mapBlockIndex.end())
         {
             if (mi->second->nChainTx && !mi->second->IsValid(BLOCK_VALID_SCRIPTS) &&
@@ -1082,11 +1067,16 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
                 CValidationState dummy;
                 ActivateBestChain(dummy, Params(), a_recent_block);
             }
+        }
+    }
+    BlockMap::iterator mi = mapBlockIndex.find(inv.hash);
+    if (mi != mapBlockIndex.end()) {
         send = BlockRequestAllowed(mi->second, consensusParams);
         if (!send) {
             LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom->GetId());
         }
     }
+    const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     // disconnect node in case we have reached the outbound limit for serving historical blocks
     // never disconnect whitelisted nodes
     if (send && connman->OutboundTargetReached(true) && ( ((pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - mi->second->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted)
@@ -1183,9 +1173,26 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
             pfrom->hashContinue.SetNull();
         }
     }
-            }
-            else if (inv.type == MSG_TX || inv.type == MSG_WITNESS_TX)
+}
+
+void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParams, CConnman* connman, const std::atomic<bool>& interruptMsgProc)
+{
+    std::deque<CInv>::iterator it = pfrom->vRecvGetData.begin();
+    std::vector<CInv> vNotFound;
+    const CNetMsgMaker msgMaker(pfrom->GetSendVersion());
     {
+        LOCK(cs_main);
+
+        while (it != pfrom->vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX)) {
+            if (interruptMsgProc)
+                return;
+            // Don't bother if send buffer is too full to respond anyway
+            if (pfrom->fPauseSend)
+                break;
+
+            const CInv &inv = *it;
+            it++;
+
             // Send stream from relay memory
             bool push = false;
             auto mi = mapRelay.find(inv.hash);
@@ -1205,15 +1212,19 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
             if (!push) {
                 vNotFound.push_back(inv);
             }
-            }
 
             // Track requests for our stuff.
             GetMainSignals().Inventory(inv.hash);
+        }
 
-            if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK)
-                break;
+        if (it != pfrom->vRecvGetData.end()) {
+            const CInv &inv = *it;
+            it++;
+            if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK) {
+                ProcessGetBlockData(pfrom, consensusParams, inv, connman, interruptMsgProc);
             }
         }
+    } // release cs_main
 
     pfrom->vRecvGetData.erase(pfrom->vRecvGetData.begin(), it);