From 330c2aacac28b9eb794b8b54a02c619d40219949 Mon Sep 17 00:00:00 2001
From: Mark Qvist <mark@unsigned.io>
Date: Mon, 13 Jan 2025 14:42:03 +0100
Subject: [PATCH] Fixed incorrect resource SDU calculation when link MTU is set

---
 RNS/Resource.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/RNS/Resource.py b/RNS/Resource.py
index a05e1b3..b0c726a 100644
--- a/RNS/Resource.py
+++ b/RNS/Resource.py
@@ -276,7 +276,10 @@ class Resource:
 
         self.status = Resource.NONE
         self.link = link
-        self.sdu = link.mdu or Resource.SDU
+        if self.link.mtu:
+            self.sdu = self.link.mtu - RNS.Reticulum.HEADER_MAXSIZE - RNS.Reticulum.IFAC_MIN_SIZE
+        else:
+            self.sdu = link.mdu or Resource.SDU
         self.max_retries = Resource.MAX_RETRIES
         self.max_adv_retries = Resource.MAX_ADV_RETRIES
         self.retries_left = self.max_retries