From 043a664cca41920c6d779da15ef39cc814ce999e Mon Sep 17 00:00:00 2001
From: Lu Wang <luwannest@users.noreply.github.com>
Date: Wed, 14 Sep 2016 09:38:45 +0800
Subject: [PATCH] Use Openthread Hardware Entropy Collector (#484)

* create new file named as hardware_entropy.c for mbedtls to use OT hardware entropy source
---
 examples/platforms/posix/random.c      |  2 +-
 third_party/mbedtls/Makefile.am        |  1 +
 third_party/mbedtls/hardware_entropy.c | 44 ++++++++++++++++++++++++++
 third_party/mbedtls/mbedtls-config.h   |  4 +--
 4 files changed, 48 insertions(+), 3 deletions(-)
 create mode 100644 third_party/mbedtls/hardware_entropy.c

diff --git a/examples/platforms/posix/random.c b/examples/platforms/posix/random.c
index cb05eed50..09dce589a 100644
--- a/examples/platforms/posix/random.c
+++ b/examples/platforms/posix/random.c
@@ -69,7 +69,7 @@ uint32_t otPlatRandomGet(void)
     return mlcg;
 }
 
-ThreadError otPlatSecureRandomGet(uint16_t aInputLength, uint8_t *aOutput, uint16_t *aOutputLength)
+ThreadError otPlatRandomSecureGet(uint16_t aInputLength, uint8_t *aOutput, uint16_t *aOutputLength)
 {
     ThreadError error = kThreadError_None;
 
diff --git a/third_party/mbedtls/Makefile.am b/third_party/mbedtls/Makefile.am
index bf38f6432..f72f48f96 100644
--- a/third_party/mbedtls/Makefile.am
+++ b/third_party/mbedtls/Makefile.am
@@ -42,6 +42,7 @@ libmbedcrypto_a_CPPFLAGS                      = \
     $(NULL)
 
 libmbedcrypto_a_SOURCES                       = \
+    hardware_entropy.c                          \
     repo/library/aes.c                          \
     repo/library/md.c                           \
     repo/library/md_wrap.c                      \
diff --git a/third_party/mbedtls/hardware_entropy.c b/third_party/mbedtls/hardware_entropy.c
new file mode 100644
index 000000000..6cc17d539
--- /dev/null
+++ b/third_party/mbedtls/hardware_entropy.c
@@ -0,0 +1,44 @@
+/*
+ *    Copyright 2016 Nest Labs Inc. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+/**
+ * @file
+ *   This file implements to use hardware entropy source.
+ *   uncomment MBEDTLS_ENTROPY_HARDWARE_ALT in mbedtls/mbedtls_config.h to use this.
+ */
+
+#include <stddef.h>
+
+#include <openthread-types.h>
+#include <platform/random.h>
+
+#include "mbedtls/entropy.h"
+
+int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len, size_t *olen)
+{
+    ThreadError error;
+
+    (void)data;
+
+    error = otPlatRandomSecureGet((uint16_t)len, (uint8_t *)output, (uint16_t *)olen);
+
+    if (error != kThreadError_None)
+    {
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+
+    return 0;
+}
diff --git a/third_party/mbedtls/mbedtls-config.h b/third_party/mbedtls/mbedtls-config.h
index 495c2d90c..bd2965617 100644
--- a/third_party/mbedtls/mbedtls-config.h
+++ b/third_party/mbedtls/mbedtls-config.h
@@ -294,7 +294,7 @@
  *
  * Uncomment to use your own hardware entropy collector.
  */
-//#define MBEDTLS_ENTROPY_HARDWARE_ALT
+#define MBEDTLS_ENTROPY_HARDWARE_ALT
 
 /**
  * \def MBEDTLS_AES_ROM_TABLES
@@ -786,7 +786,7 @@
  *
  * Uncomment this macro to disable the built-in platform entropy functions.
  */
-//#define MBEDTLS_NO_PLATFORM_ENTROPY
+#define MBEDTLS_NO_PLATFORM_ENTROPY
 
 /**
  * \def MBEDTLS_ENTROPY_FORCE_SHA256