Implement PushReconstructedRecoveredSig in CSigningManager

We can reconstruct recovered sigs from other P2P messages to avoid
re-validation of those. We will do this later in InstantSend code.

src/llmq/quorums_signing.cpp

@@ -440,11 +440,25 @@ void CSigningManager::CollectPendingRecoveredSigsToVerify(
     }
 }
 
+bool CSigningManager::ProcessPendingReconstructedRecoveredSigs()
+{
+    decltype(pendingReconstructedRecoveredSigs) l;
+    {
+        LOCK(cs);
+        l = std::move(pendingReconstructedRecoveredSigs);
+    }
+    for (auto& p : l) {
+        ProcessRecoveredSig(-1, p.first, p.second, *g_connman);
+    }
+}
+
 bool CSigningManager::ProcessPendingRecoveredSigs(CConnman& connman)
 {
     std::unordered_map<NodeId, std::list<CRecoveredSig>> recSigsByNode;
     std::unordered_map<std::pair<Consensus::LLMQType, uint256>, CQuorumCPtr, StaticSaltedHasher> quorums;
 
+    ProcessPendingReconstructedRecoveredSigs();
+
     CollectPendingRecoveredSigsToVerify(32, recSigsByNode, quorums);
     if (recSigsByNode.empty()) {
         return false;
@@ -550,6 +564,12 @@ void CSigningManager::ProcessRecoveredSig(NodeId nodeId, const CRecoveredSig& re
     }
 }
 
+void CSigningManager::PushReconstructedRecoveredSig(const llmq::CRecoveredSig& recoveredSig, const llmq::CQuorumCPtr& quorum)
+{
+    LOCK(cs);
+    pendingReconstructedRecoveredSigs.emplace_back(recoveredSig, quorum);
+}
+
 void CSigningManager::Cleanup()
 {
     int64_t now = GetTimeMillis();

src/llmq/quorums_signing.h

@@ -126,6 +126,7 @@ class CSigningManager
 
     // Incoming and not verified yet
     std::unordered_map<NodeId, std::list<CRecoveredSig>> pendingRecoveredSigs;
+    std::list<std::pair<CRecoveredSig, CQuorumCPtr>> pendingReconstructedRecoveredSigs;
 
     // must be protected by cs
     FastRandomContext rnd;
@@ -142,13 +143,18 @@ class CSigningManager
 
     void ProcessMessage(CNode* pnode, const std::string& strCommand, CDataStream& vRecv, CConnman& connman);
 
+    // This is called when a recovered signature was was reconstructed from another P2P message and is known to be valid
+    // This is the case for example when a signature appears as part of InstantSend or ChainLocks
+    void PushReconstructedRecoveredSig(const CRecoveredSig& recoveredSig, const CQuorumCPtr& quorum);
+
 private:
     void ProcessMessageRecoveredSig(CNode* pfrom, const CRecoveredSig& recoveredSig, CConnman& connman);
     bool PreVerifyRecoveredSig(NodeId nodeId, const CRecoveredSig& recoveredSig, bool& retBan);
 
     void CollectPendingRecoveredSigsToVerify(size_t maxUniqueSessions,
             std::unordered_map<NodeId, std::list<CRecoveredSig>>& retSigShares,
             std::unordered_map<std::pair<Consensus::LLMQType, uint256>, CQuorumCPtr, StaticSaltedHasher>& retQuorums);
+    bool ProcessPendingReconstructedRecoveredSigs();
     bool ProcessPendingRecoveredSigs(CConnman& connman); // called from the worker thread of CSigSharesManager
     void ProcessRecoveredSig(NodeId nodeId, const CRecoveredSig& recoveredSig, const CQuorumCPtr& quorum, CConnman& connman);
     void Cleanup(); // called from the worker thread of CSigSharesManager