Don't allow passthrough subclients to reconnect

src/stratifier.c

@@ -3343,6 +3343,12 @@ out_unlock:
 	return ret;
 }
 
+/* passthrough subclients have client_ids in the high bits */
+static inline bool passthrough_subclient(const int64_t client_id)
+{
+	return (client_id > 0xffffffffll);
+}
+
 /* Extranonce1 must be set here. Needs to be entered with client holding a ref
  * count. */
 static json_t *parse_subscribe(stratum_instance_t *client, const int64_t client_id, const json_t *params_val)
@@ -3386,7 +3392,7 @@ static json_t *parse_subscribe(stratum_instance_t *client, const int64_t client_
 			session_id = int_from_sessionid(buf);
 			LOGDEBUG("Found old session id %d", session_id);
 		}
-		if (!ckp->proxy && session_id) {
+		if (!ckp->proxy && session_id && !passthrough_subclient(client_id)) {
 			if ((client->enonce1_64 = disconnected_sessionid_exists(sdata, session_id, client_id))) {
 				sprintf(client->enonce1, "%016lx", client->enonce1_64);
 				old_match = true;