1 files changed, 53 insertions, 49 deletions

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 7e9bb2f27c..018541a597 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1608,6 +1608,37 @@ void static ProcessGetBlockData(CNode* pfrom, const CChainParams& chainparams, c
     }
 }
 
+//! Determine whether or not a peer can request a transaction, and return it (or nullptr if not found or not allowed).
+CTransactionRef static FindTxForGetData(CNode* peer, const uint256& txid, const std::chrono::seconds mempool_req, const std::chrono::seconds longlived_mempool_time) LOCKS_EXCLUDED(cs_main)
+{
+    // Check if the requested transaction is so recent that we're just
+    // about to announce it to the peer; if so, they certainly shouldn't
+    // know we already have it.
+    {
+        LOCK(peer->m_tx_relay->cs_tx_inventory);
+        if (peer->m_tx_relay->setInventoryTxToSend.count(txid)) return {};
+    }
+
+    {
+        LOCK(cs_main);
+        // Look up transaction in relay pool
+        auto mi = mapRelay.find(txid);
+        if (mi != mapRelay.end()) return mi->second;
+    }
+
+    auto txinfo = mempool.info(txid);
+    if (txinfo.tx) {
+        // To protect privacy, do not answer getdata using the mempool when
+        // that TX couldn't have been INVed in reply to a MEMPOOL request,
+        // or when it's too recent to have expired from mapRelay.
+        if ((mempool_req.count() && txinfo.m_time <= mempool_req) || txinfo.m_time <= longlived_mempool_time) {
+            return txinfo.tx;
+        }
+    }
+
+    return {};
+}
+
 void static ProcessGetData(CNode* pfrom, const CChainParams& chainparams, CConnman* connman, CTxMemPool& mempool, const std::atomic<bool>& interruptMsgProc) LOCKS_EXCLUDED(cs_main)
 {
     AssertLockNotHeld(cs_main);
@@ -1622,58 +1653,31 @@ void static ProcessGetData(CNode* pfrom, const CChainParams& chainparams, CConnm
     const std::chrono::seconds mempool_req = pfrom->m_tx_relay != nullptr ? pfrom->m_tx_relay->m_last_mempool_req.load()
                                                                           : std::chrono::seconds::min();
 
-    {
-        LOCK(cs_main);
+    // Process as many TX items from the front of the getdata queue as
+    // possible, since they're common and it's efficient to batch process
+    // them.
+    while (it != pfrom->vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX)) {
+        if (interruptMsgProc) return;
+        // The send buffer provides backpressure. If there's no space in
+        // the buffer, pause processing until the next call.
+        if (pfrom->fPauseSend) break;
 
-        // Process as many TX items from the front of the getdata queue as
-        // possible, since they're common and it's efficient to batch process
-        // them.
-        while (it != pfrom->vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX)) {
-            if (interruptMsgProc)
-                return;
-            // The send buffer provides backpressure. If there's no space in
-            // the buffer, pause processing until the next call.
-            if (pfrom->fPauseSend)
-                break;
-
-            const CInv &inv = *it++;
+        const CInv &inv = *it++;
 
-            if (pfrom->m_tx_relay == nullptr) {
-                // Ignore GETDATA requests for transactions from blocks-only peers.
-                continue;
-            }
+        if (pfrom->m_tx_relay == nullptr) {
+            // Ignore GETDATA requests for transactions from blocks-only peers.
+            continue;
+        }
 
-            // Send stream from relay memory
-            bool push = false;
-            auto mi = mapRelay.find(inv.hash);
+        CTransactionRef tx = FindTxForGetData(pfrom, inv.hash, mempool_req, longlived_mempool_time);
+        if (tx) {
             int nSendFlags = (inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0);
-            if (mi != mapRelay.end()) {
-                connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second));
-                push = true;
-            } else {
-                auto txinfo = mempool.info(inv.hash);
-                // To protect privacy, do not answer getdata using the mempool when
-                // that TX couldn't have been INVed in reply to a MEMPOOL request,
-                // or when it's too recent to have expired from mapRelay.
-                if (txinfo.tx && (
-                     (mempool_req.count() && txinfo.m_time <= mempool_req)
-                      || (txinfo.m_time <= longlived_mempool_time)))
-                {
-                    connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *txinfo.tx));
-                    push = true;
-                }
-            }
-
-            if (push) {
-                // We interpret fulfilling a GETDATA for a transaction as a
-                // successful initial broadcast and remove it from our
-                // unbroadcast set.
-                mempool.RemoveUnbroadcastTx(inv.hash);
-            } else {
-                vNotFound.push_back(inv);
-            }
+            connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *tx));
+            mempool.RemoveUnbroadcastTx(inv.hash);
+        } else {
+            vNotFound.push_back(inv);
         }
-    } // release cs_main
+    }
 
     // Only process one BLOCK item per call, since they're uncommon and can be
     // expensive to process.
@@ -2671,8 +2675,8 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
 
     if (msg_type == NetMsgType::TX) {
         // Stop processing the transaction early if
-        // We are in blocks only mode and peer is either not whitelisted or whitelistrelay is off
-        // or if this peer is supposed to be a block-relay-only peer
+        // 1) We are in blocks only mode and peer has no relay permission
+        // 2) This peer is a block-relay-only peer
         if ((!g_relay_txes && !pfrom->HasPermission(PF_RELAY)) || (pfrom->m_tx_relay == nullptr))
         {
             LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom->GetId());