From c81ad17305725d1ed363be84f0dab33b36b94b58 Mon Sep 17 00:00:00 2001
From: Carl Friess <carl.friess@me.com>
Date: Fri, 13 Dec 2024 16:50:10 +0100
Subject: [PATCH] Ignore invalid function codes sent to other servers

---
 nanomodbus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nanomodbus.c b/nanomodbus.c
index 6583217..30bc17c 100644
--- a/nanomodbus.c
+++ b/nanomodbus.c
@@ -1878,7 +1878,8 @@ static nmbs_error handle_req_fc(nmbs_t* nmbs) {
 #endif
         default:
             flush(nmbs);
-            err = send_exception_msg(nmbs, NMBS_EXCEPTION_ILLEGAL_FUNCTION);
+            if (!nmbs->msg.ignored && !nmbs->msg.broadcast)
+                err = send_exception_msg(nmbs, NMBS_EXCEPTION_ILLEGAL_FUNCTION);
     }
 
     return err;