Merge #19723: Ignore unknown messages before VERACK

675e55e Ignore unknown messages before VERACK (Suhas Daftuar)

Pull request description:

  This allows for feature negotiation to take place with messages between VERSION and VERACK in the future, without requiring additional software changes to specifically ignore messages for features that are unimplemented by our software.

ACKs for top commit:
  sipa:
    utACK 675e55e
  practicalswift:
    ACK 675e55e: patch looks correct
  MarcoFalke:
    ACK 675e55e
  hebasto:
    ACK 675e55e, the offender peer will be eventually disconnected due to the timeout.

Tree-SHA512: 8d2b1d8b9843f2ee26b2c30f7c5ff0bfcfbe3f46b32cd0369c48ece26624151091237e83ce3f18c6da004099026602cfab1642ac916db777f047d170b365c007

Author: MarcoFalke

src/net_processing.cpp

@@ -2604,8 +2604,7 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
     }
 
     if (!pfrom.fSuccessfullyConnected) {
-        // Must have a verack message before anything else
-        Misbehaving(pfrom.GetId(), 1, "non-verack message before version handshake");
+        LogPrint(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId());
         return;
     }