From 222e2ff421609a7ff5e0565156028771d284f7ad Mon Sep 17 00:00:00 2001
From: Steven Cooreman <steven.cooreman@silabs.com>
Date: Tue, 4 Apr 2017 11:37:15 +0200
Subject: [PATCH] Allow alternate core implementation of CCM

---
 include/mbedtls/ccm.h    | 16 ++++++++++++++++
 include/mbedtls/config.h |  1 +
 library/ccm.c            |  3 +++
 3 files changed, 20 insertions(+)

diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index ef75839ba..579402fd4 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -28,6 +28,10 @@
 #define MBEDTLS_ERR_CCM_BAD_INPUT      -0x000D /**< Bad input parameters to function. */
 #define MBEDTLS_ERR_CCM_AUTH_FAILED    -0x000F /**< Authenticated decryption failed. */
 
+#if !defined(MBEDTLS_CCM_ALT)
+// Regular implementation
+//
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -125,6 +129,18 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len );
 
+#ifdef __cplusplus
+}
+#endif
+
+#else  /* !MBEDTLS_CCM_ALT */
+#include "ccm_alt.h"
+#endif /* !MBEDTLS_CCM_ALT */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /**
  * \brief          Checkup routine
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 0f7e29bcf..941769fd0 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -237,6 +237,7 @@
 //#define MBEDTLS_ARC4_ALT
 //#define MBEDTLS_BLOWFISH_ALT
 //#define MBEDTLS_CAMELLIA_ALT
+//#define MBEDTLS_CCM_ALT
 //#define MBEDTLS_DES_ALT
 //#define MBEDTLS_XTEA_ALT
 //#define MBEDTLS_MD2_ALT
diff --git a/library/ccm.c b/library/ccm.c
index 13a8fd1a2..9101e5f7c 100644
--- a/library/ccm.c
+++ b/library/ccm.c
@@ -49,6 +49,8 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
 
+#if !defined(MBEDTLS_CCM_ALT)
+
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
@@ -348,6 +350,7 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
     return( 0 );
 }
 
+#endif /* !MBEDTLS_CCM_ALT */
 
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /*