From 52669a925a86cfd9180086e7957bcd6f2b1194a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Duda?= <lukasz.duda@nordicsemi.no>
Date: Fri, 26 Oct 2018 06:08:17 +0200
Subject: [PATCH] [coap] add support for CoAP header exceeding 255 bytes
 (#3210)

---
 include/openthread/coap.h     | 4 ++--
 src/core/coap/coap_header.cpp | 2 +-
 src/core/coap/coap_header.hpp | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/openthread/coap.h b/include/openthread/coap.h
index 8a73d58e7..4cfed8d8d 100644
--- a/include/openthread/coap.h
+++ b/include/openthread/coap.h
@@ -165,7 +165,7 @@ typedef enum otCoapOptionContentFormat {
     OT_COAP_OPTION_CONTENT_FORMAT_JWS          = 101 ///< application/json-web-signature
 } otCoapOptionContentFormat;
 
-#define OT_COAP_HEADER_MAX_LENGTH 128 ///< Max CoAP header length (bytes)
+#define OT_COAP_HEADER_MAX_LENGTH 512 ///< Max CoAP header length (bytes)
 
 /**
  * This structure represents a CoAP header.
@@ -183,7 +183,7 @@ typedef struct otCoapHeader
         } mFields;                                 ///< Structure representing a CoAP base header
         uint8_t mBytes[OT_COAP_HEADER_MAX_LENGTH]; ///< The raw byte encoding for the CoAP header
     } mHeader;                                     ///< The CoAP header encoding
-    uint8_t      mHeaderLength;                    ///< The CoAP header length (bytes)
+    uint16_t     mHeaderLength;                    ///< The CoAP header length (bytes)
     uint16_t     mOptionLast;                      ///< The last CoAP Option Number value
     uint16_t     mFirstOptionOffset;               ///< The byte offset for the first CoAP Option
     uint16_t     mNextOptionOffset;                ///< The byte offset for the next CoAP Option
diff --git a/src/core/coap/coap_header.cpp b/src/core/coap/coap_header.cpp
index 052efcfe3..7c86d4889 100644
--- a/src/core/coap/coap_header.cpp
+++ b/src/core/coap/coap_header.cpp
@@ -249,7 +249,7 @@ otError Header::AppendOption(const Option &aOption)
     memcpy(cur, aOption.mValue, aOption.mLength);
     cur += aOption.mLength;
 
-    mHeaderLength += static_cast<uint8_t>(cur - buf);
+    mHeaderLength += static_cast<uint16_t>(cur - buf);
     mOptionLast = aOption.mNumber;
 
 exit:
diff --git a/src/core/coap/coap_header.hpp b/src/core/coap/coap_header.hpp
index d5a067e1d..cf8e30e38 100644
--- a/src/core/coap/coap_header.hpp
+++ b/src/core/coap/coap_header.hpp
@@ -402,7 +402,7 @@ public:
      * @returns The header length in bytes.
      *
      */
-    uint8_t GetLength(void) const { return mHeaderLength; }
+    uint16_t GetLength(void) const { return mHeaderLength; }
 
     /**
      * This method sets a default response header based on request header.