Merge bitcoin/bitcoin#26551: p2p: Track orphans by who provided them

c58c249a5b694c88122589fedbef4e2f13f08bb4 net_processing: indicate more work to do when orphans are ready to reconsider (Anthony Towns)
ecb0a3e4259b81d6bb74d59a58eb65552c17d8d8 net_processing: Don't process tx after processing orphans (Anthony Towns)
c5837757068bf8ea3e5b6fdad82f69d1deb81545 net_processing: only process orphans before messages (Anthony Towns)
be2304676bedcd15debcdc694549fdd2b255ba62 txorphange: Drop redundant originator arg from GetTxToReconsider (Anthony Towns)
a4fe09973aa82210b98dcb4e4e9f11ef59780f9b txorphanage: index workset by originating peer (Anthony Towns)

Pull request description:

  We currently process orphans by assigning them to the peer that provided a missing parent; instead assign them to the peer that provided the orphan in the first place. This prevents a peer from being able to marginally delay another peer's transactions and also simplifies the internal API slightly. Because we're now associating orphan processing with the peer that provided the orphan originally, we no longer process orphans immediately after receiving the parent, but defer until a future call to `ProcessMessage`.

  Based on #26295

ACKs for top commit:
  naumenkogs:
    utACK c58c249a5b694c88122589fedbef4e2f13f08bb4
  glozow:
    ACK c58c249a5b694c88122589fedbef4e2f13f08bb4
  mzumsande:
    Code Review ACK c58c249a5b694c88122589fedbef4e2f13f08bb4

Tree-SHA512: 3186c346f21e60440266a2a80a9d23d7b96071414e14b2b3bfe50457c04c18b1eab109c3d8c2a7726a6b10a2eda1f0512510a52c102da112820a26f5d96f12de

1 files changed, 18 insertions, 7 deletions

diff --git a/src/txorphanage.cpp b/src/txorphanage.cpp
index 94f64abca7..19f9fae998 100644
--- a/src/txorphanage.cpp
+++ b/src/txorphanage.cpp
@@ -145,17 +145,19 @@ void TxOrphanage::LimitOrphans(unsigned int max_orphans)
     if (nEvicted > 0) LogPrint(BCLog::MEMPOOL, "orphanage overflow, removed %u tx\n", nEvicted);
 }
 
-void TxOrphanage::AddChildrenToWorkSet(const CTransaction& tx, NodeId peer)
+void TxOrphanage::AddChildrenToWorkSet(const CTransaction& tx)
 {
     LOCK(m_mutex);
 
-    // Get this peer's work set, emplacing an empty set it didn't exist
-    std::set<uint256>& orphan_work_set = m_peer_work_set.try_emplace(peer).first->second;
 
     for (unsigned int i = 0; i < tx.vout.size(); i++) {
         const auto it_by_prev = m_outpoint_to_orphan_it.find(COutPoint(tx.GetHash(), i));
         if (it_by_prev != m_outpoint_to_orphan_it.end()) {
             for (const auto& elem : it_by_prev->second) {
+                // Get this source peer's work set, emplacing an empty set if it didn't exist
+                // (note: if this peer wasn't still connected, we would have removed the orphan tx already)
+                std::set<uint256>& orphan_work_set = m_peer_work_set.try_emplace(elem->second.fromPeer).first->second;
+                // Add this tx to the work set
                 orphan_work_set.insert(elem->first);
             }
         }
@@ -172,7 +174,7 @@ bool TxOrphanage::HaveTx(const GenTxid& gtxid) const
     }
 }
 
-CTransactionRef TxOrphanage::GetTxToReconsider(NodeId peer, NodeId& originator, bool& more)
+CTransactionRef TxOrphanage::GetTxToReconsider(NodeId peer)
 {
     LOCK(m_mutex);
 
@@ -185,16 +187,25 @@ CTransactionRef TxOrphanage::GetTxToReconsider(NodeId peer, NodeId& originator,
 
             const auto orphan_it = m_orphans.find(txid);
             if (orphan_it != m_orphans.end()) {
-                more = !work_set.empty();
-                originator = orphan_it->second.fromPeer;
                 return orphan_it->second.tx;
             }
         }
     }
-    more = false;
     return nullptr;
 }
 
+bool TxOrphanage::HaveTxToReconsider(NodeId peer)
+{
+    LOCK(m_mutex);
+
+    auto work_set_it = m_peer_work_set.find(peer);
+    if (work_set_it != m_peer_work_set.end()) {
+        auto& work_set = work_set_it->second;
+        return !work_set.empty();
+    }
+    return false;
+}
+
 void TxOrphanage::EraseForBlock(const CBlock& block)
 {
     LOCK(m_mutex);