From 758cac3bedccedeece8f59279b8ffa95bac21241 Mon Sep 17 00:00:00 2001
From: anthony-crystalpeak
 <108027248+anthony-crystalpeak@users.noreply.github.com>
Date: Thu, 13 Jul 2023 12:12:38 -0700
Subject: [PATCH] DOS: port might be null (#451)

---
 apps/router-mstp/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/apps/router-mstp/main.c b/apps/router-mstp/main.c
index 5f1073af..592778ae 100644
--- a/apps/router-mstp/main.c
+++ b/apps/router-mstp/main.c
@@ -901,7 +901,7 @@ static void routed_apdu_handler(uint16_t snet,
             datalink_send_pdu(port->net, &remote_dest, npdu, &Tx_Buffer[0],
                 npdu_len + apdu_len);
         }
-    } else if (dest->net) {
+    } else if (port && dest->net) {
         debug_printf("Routing to Unknown Route %u\n", (unsigned)dest->net);
         /* Case 3: a global broadcast is required. */
         dest->mac_len = 0;