esp_https_server : change config option secure_enable to transport_mode and some minor changes

transport_mode accepts enum httpd_ssl_transport_t instead of true/false.
This will allow for extension to dual mode (server running on both secure and insecure ports) in the future.

components/esp_https_server/include/esp_https_server.h

@@ -19,6 +19,11 @@
 #include "esp_err.h"
 #include "esp_http_server.h"
 
+typedef enum {
+    HTTPD_SSL_TRANSPORT_SECURE,      // SSL Enabled
+    HTTPD_SSL_TRANSPORT_INSECURE     // SSL disabled
+} httpd_ssl_transport_mode_t;
+
 /**
  * HTTPS server config struct
  *
@@ -44,13 +49,13 @@ struct httpd_ssl_config {
     /** Private key byte length */
     size_t prvtkey_len;
 
-    /** Enable SSL (default true) */
-    bool secure_enable;
+    /** Transport Mode (default secure) */
+    httpd_ssl_transport_mode_t transport_mode;
 
-    /** Port used when SSL is enabled (default 443) */
+    /** Port used when transport mode is secure (default 443) */
     uint16_t port_secure;
 
-    /** Port used when SSL is disabled (default 80) */
+    /** Port used when transport mode is insecure (default 80) */
     uint16_t port_insecure;
 };
 
@@ -62,7 +67,7 @@ typedef struct httpd_ssl_config httpd_ssl_config_t;
  * (http_server default config had to be copied for customization)
  *
  * Notes:
- * - port is set when starting the server, according to 'secure_enable'
+ * - port is set when starting the server, according to 'transport_mode'
  * - one socket uses ~ 40kB RAM with SSL, we reduce the default socket count to 4
  * - SSL sockets are usually long-lived, closing LRU prevents pool exhaustion DOS
  * - Stack size may need adjustments depending on the user application
@@ -87,7 +92,7 @@ typedef struct httpd_ssl_config httpd_ssl_config_t;
         .open_fn = NULL,                          \
         .close_fn = NULL,                         \
     },                                            \
-    .secure_enable = true,                        \
+    .transport_mode = HTTPD_SSL_TRANSPORT_SECURE, \
     .port_secure = 443,                           \
     .port_insecure = 80,                          \
 }

components/esp_https_server/src/https_server.c

@@ -118,9 +118,9 @@ static esp_err_t httpd_ssl_open(httpd_handle_t server, int sockfd)
     httpd_sess_set_transport_ctx(server, sockfd, ssl, httpd_ssl_close);
 
     // Set rx/tx/pending override functions
-    httpd_set_sess_send_override(server, sockfd, httpd_ssl_send);
-    httpd_set_sess_recv_override(server, sockfd, httpd_ssl_recv);
-    httpd_set_sess_pending_override(server, sockfd, httpd_ssl_pending);
+    httpd_sess_set_send_override(server, sockfd, httpd_ssl_send);
+    httpd_sess_set_recv_override(server, sockfd, httpd_ssl_recv);
+    httpd_sess_set_pending_override(server, sockfd, httpd_ssl_pending);
 
     // all access should now go through SSL
 
@@ -183,7 +183,7 @@ esp_err_t httpd_ssl_start(httpd_handle_t *pHandle, struct httpd_ssl_config *conf
 
     ESP_LOGI(TAG, "Starting server");
 
-    if (config->secure_enable) {
+    if (HTTPD_SSL_TRANSPORT_SECURE == config->transport_mode) {
         SSL_CTX *ctx = create_secure_context(config);
         if (!ctx) {
             return ESP_FAIL;