mbedTLS: Add generic support for mbedTLS debug output via the esp_log functionality

components/mbedtls/Kconfig

@@ -24,15 +24,12 @@ config MBEDTLS_DEBUG
    bool "Enable mbedTLS debugging"
    default n
    help
-       Enable mbedTLS debugging functions.
-       
-       If this option is enabled, use the mbedtls_debug_set_threshold()
-       and mbedtls_ssl_conf_dbg() functions to obtain debugging output
-       from mbedTLS.
-       
-       Note thatm mbedTLS debugging is not related to the ESP logging
-       functionality. See the "https_request_main" example for a
-       sample function which connects the two together.
+       Enable mbedTLS debugging functions at compile time.
+
+       If this option is enabled, you can include
+	   "mbedtls/esp_debug.h" and call mbedtls_esp_enable_debug_log()
+	   at runtime in order to enable mbedTLS debug output via the ESP
+	   log mechanism.
 
 config MBEDTLS_HARDWARE_AES
    bool "Enable hardware AES acceleration"

components/mbedtls/port/include/mbedtls/esp_debug.h

@@ -0,0 +1,45 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+#include "sdkconfig.h"
+#ifdef CONFIG_MBEDTLS_DEBUG
+
+/** @brief Enable mbedTLS debug logging via the esp_log mechanism.
+ *
+ * mbedTLS internal debugging is filtered from a specified mbedTLS
+ * threshold level to esp_log level at runtime:
+ *
+ * - 1 - Warning
+ * - 2 - Info
+ * - 3 - Debug
+ * - 4 - Verbose
+ *
+ * (Note that mbedTLS debug thresholds are not always consistently used.)
+ *
+ * This function will set the esp log level for "mbedtls" to the specified mbedTLS
+ * threshold level that matches. However, the overall max ESP log level must be set high
+ * enough in menuconfig, or some messages may be filtered at compile time.
+ *
+ * @param conf mbedtls_ssl_config structure
+ * @param mbedTLS debug threshold, 0-4. Messages are filtered at runtime.
+ */
+void mbedtls_esp_enable_debug_log(mbedtls_ssl_config *conf, int threshold);
+
+/** @brief Disable mbedTLS debug logging via the esp_log mechanism.
+ *
+ */
+void mbedtls_esp_disable_debug_log(mbedtls_ssl_config *conf);
+
+
+#endif

components/mbedtls/port/mbedtls_debug.c

@@ -0,0 +1,86 @@
+// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+
+#include <strings.h>
+
+#include "esp_log.h"
+#include "mbedtls/platform.h"
+#include "mbedtls/debug.h"
+#include "mbedtls/ssl.h"
+#include "mbedtls/esp_debug.h"
+
+static const char *TAG = "mbedtls";
+
+static void mbedtls_esp_debug(void *ctx, int level,
+                              const char *file, int line,
+                              const char *str);
+
+void mbedtls_esp_enable_debug_log(mbedtls_ssl_config *conf, int threshold)
+{
+    mbedtls_debug_set_threshold(threshold);
+    mbedtls_ssl_conf_dbg(conf, mbedtls_esp_debug, NULL);
+    esp_log_level_t level = ESP_LOG_NONE;
+    switch(threshold) {
+    case 1:
+        level = ESP_LOG_WARN;
+    case 2:
+        level = ESP_LOG_INFO;
+    case 3:
+        level = ESP_LOG_DEBUG;
+    case 4:
+        level = ESP_LOG_VERBOSE;
+    }
+    esp_log_level_set(TAG, level);
+}
+
+void mbedtls_esp_disable_debug_log(mbedtls_ssl_config *conf)
+{
+    mbedtls_ssl_conf_dbg(conf, NULL, NULL);
+}
+
+/* Default mbedtls debug function that translates mbedTLS debug output
+   to ESP_LOGx debug output.
+*/
+static void mbedtls_esp_debug(void *ctx, int level,
+                     const char *file, int line,
+                     const char *str)
+{
+    char *file_sep;
+
+    /* Shorten 'file' from the whole file path to just the filename
+
+       This is a bit wasteful because the macros are compiled in with
+       the full _FILE_ path in each case.
+    */
+    file_sep = rindex(file, '/');
+    if(file_sep)
+        file = file_sep+1;
+
+    switch(level) {
+    case 1:
+        ESP_LOGW(TAG, "%s:%d %s", file, line, str);
+        break;
+    case 2:
+        ESP_LOGI(TAG, "%s:%d %s", file, line, str);
+        break;
+    case 3:
+        ESP_LOGD(TAG, "%s:%d %s", file, line, str);
+    case 4:
+        ESP_LOGV(TAG, "%s:%d %s", file, line, str);
+        break;
+    default:
+        ESP_LOGE(TAG, "Unexpected log level %d: %s", level, str);
+        break;
+    }
+}