[net_processing] ignore all transactions during ibd

Co-authored-by: Amiti Uttarwar <amiti@uttarwar.org>

src/net_processing.cpp

@@ -3207,6 +3207,11 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             return;
         }
 
+        // Stop processing the transaction early if we are still in IBD since we don't
+        // have enough information to validate it yet. Sending unsolicited transactions
+        // is not considered a protocol violation, so don't punish the peer.
+        if (m_chainman.ActiveChainstate().IsInitialBlockDownload()) return;
+
         CTransactionRef ptx;
         vRecv >> ptx;
         const CTransaction& tx = *ptx;