From a4d7c29313a3624f4d0df791a84959f53dc0dc83 Mon Sep 17 00:00:00 2001
From: "Florek, Bartlomiej" <bartlomiej.florek@assaabloy.com>
Date: Wed, 25 Feb 2026 10:18:56 +0000
Subject: [PATCH] fix(config): enhance Zephyr configuration for libcoap

---
 include/coap3/coap_session_internal.h |  3 ++
 zephyr/CMakeLists.txt                 | 13 +++++++--
 zephyr/Kconfig                        | 42 +++++++++++++++++++++++++--
 3 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/include/coap3/coap_session_internal.h b/include/coap3/coap_session_internal.h
index aa14c24e..f1948d82 100644
--- a/include/coap3/coap_session_internal.h
+++ b/include/coap3/coap_session_internal.h
@@ -24,7 +24,10 @@
 extern "C" {
 #endif
 
+#ifndef COAP_DEFAULT_SESSION_TIMEOUT
 #define COAP_DEFAULT_SESSION_TIMEOUT 300
+#endif /* !COAP_DEFAULT_SESSION_TIMEOUT */
+
 #define COAP_PARTIAL_SESSION_TIMEOUT_TICKS (30 * COAP_TICKS_PER_SECOND)
 #define COAP_DEFAULT_MAX_HANDSHAKE_SESSIONS 100
 
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 3604931c..8a36ae6f 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -171,8 +171,17 @@ if(CONFIG_LIBCOAP)
   endif()
 
   add_subdirectory(.. build)
-  target_compile_definitions(coap-3 PUBLIC WITH_ZEPHYR)
-  target_compile_definitions(coap-3 PUBLIC COAP_MEMORY_TYPE_TRACK=1)
+  target_compile_definitions(coap-3
+    PUBLIC
+      WITH_ZEPHYR
+      COAP_MEMORY_TYPE_TRACK=1
+      $<$<BOOL:${CONFIG_LIBCOAP_OBS_MAX_NON}>:COAP_OBS_MAX_NON=${CONFIG_LIBCOAP_OBS_MAX_NON}>
+      $<$<BOOL:${CONFIG_LIBCOAP_DEFAULT_MAX_PDU_RX_SIZE}>:COAP_DEFAULT_MAX_PDU_RX_SIZE=${CONFIG_LIBCOAP_DEFAULT_MAX_PDU_RX_SIZE}>
+      $<$<BOOL:${CONFIG_LIBCOAP_RXBUFFER_SIZE}>:COAP_RXBUFFER_SIZE=${CONFIG_LIBCOAP_RXBUFFER_SIZE}>
+      $<$<BOOL:${CONFIG_LIBCOAP_DEFAULT_MTU}>:COAP_DEFAULT_MTU=${CONFIG_LIBCOAP_DEFAULT_MTU}>
+      $<$<BOOL:${CONFIG_LIBCOAP_DEFAULT_SESSION_TIMEOUT}>:COAP_DEFAULT_SESSION_TIMEOUT=${CONFIG_LIBCOAP_DEFAULT_SESSION_TIMEOUT}>
+    )
+
   target_link_libraries(coap-3 PUBLIC zephyr_interface)
 
   set_property(GLOBAL APPEND PROPERTY ZEPHYR_INTERFACE_LIBS coap-3)
diff --git a/zephyr/Kconfig b/zephyr/Kconfig
index e692bc65..6dd68b1b 100644
--- a/zephyr/Kconfig
+++ b/zephyr/Kconfig
@@ -83,7 +83,7 @@ config LIBCOAP_ASYNC_SUPPORT
     help
         Enable async separate responses functionality for CoAP.
 
-        If this option is disabled, redundent CoAP async separate responses code is removed.
+        If this option is disabled, redundant CoAP async separate responses code is removed.
 
 config LIBCOAP_THREAD_SAFE_SUPPORT
     bool "Enable thread safe support within CoAP"
@@ -121,7 +121,7 @@ config LIBCOAP_CLIENT_SUPPORT
         If this option is disabled, redundant CoAP client only code is
         removed.
         If both this option and LIBCOAP_SERVER_SUPPORT are disabled, then
-        both are automatically enabled for backwards compatability.
+        both are automatically enabled for backwards compatibility.
 
 config LIBCOAP_SERVER_SUPPORT
     bool "Enable Server functionality within CoAP"
@@ -133,7 +133,7 @@ config LIBCOAP_SERVER_SUPPORT
         If this option is disabled, redundant CoAP server only code is
         removed.
         If both this option and LIBCOAP_CLIENT_SUPPORT are disabled, then
-        both are automatically enabled for backwards compatability.
+        both are automatically enabled for backwards compatibility.
 
 config LIBCOAP_DEBUGGING
     bool "Enable CoAP debugging"
@@ -186,6 +186,42 @@ config LIBCOAP_LOG_DEFAULT_LEVEL
     default 7 if LIBCOAP_LOG_DEBUG
     default 8 if LIBCOAP_LOG_OSCORE
 
+config LIBCOAP_DEFAULT_MAX_PDU_RX_SIZE
+    int "Default max PDU RX size in bytes"
+    default 1152
+    help
+        Maximum size of incoming CoAP PDU. RFC7252 4.6 suggests 1152.
+        Increase for larger block-wise transfers (e.g. 1024-4096).
+
+config LIBCOAP_RXBUFFER_SIZE
+    int "Receive buffer size in bytes"
+    default 1472
+    help
+        Size of the socket receive buffer for incoming CoAP/UDP packets.
+        Should be at least as large as the largest expected PDU (e.g. 1472
+        for typical Ethernet MTU minus headers).
+
+config LIBCOAP_DEFAULT_MTU
+    int "Default MTU in bytes"
+    default 1152
+    help
+        Default path/session MTU used for CoAP (RFC7252 4.6 suggests 1152).
+        Used for session MTU and PDU sizing; increase for larger block-wise
+        transfers.
+
+config LIBCOAP_OBS_MAX_NON
+    int "Observe: max NON notifications before CON"
+    default 5
+    range 1 255
+    help
+        Number of NON notifications before sending a CON (RFC7641 4.5).
+
+config LIBCOAP_DEFAULT_SESSION_TIMEOUT
+    int "Default session timeout"
+    default 300
+    help
+        This setting refers to the COAP_DEFAULT_SESSION_TIMEOUT, which defines server session's timeout.
+
 if MBEDTLS
 
 config MBEDTLS_CIPHER_CCM_ENABLED