transport: Support bind socket to specified interface in transport and esp-tls

components/esp-tls/esp_tls.c

@@ -231,6 +231,15 @@ static esp_err_t esp_tls_set_socket_options(int fd, const esp_tls_cfg_t *cfg)
                 return ESP_ERR_ESP_TLS_SOCKET_SETOPT_FAILED;
             }
         }
+        if (cfg->if_name) {
+            if (cfg->if_name->ifr_name[0] != 0) {
+                ESP_LOGD(TAG, "Bind [sock=%d] to interface %s", fd, cfg->if_name->ifr_name);
+                if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,  cfg->if_name, sizeof(struct ifreq)) != 0) {
+                    ESP_LOGE(TAG, "Bind [sock=%d] to interface %s fail", fd, cfg->if_name->ifr_name);
+                    return ESP_ERR_ESP_TLS_SOCKET_SETOPT_FAILED;
+                }
+            }
+        }
     }
     return ESP_OK;
 }
@@ -266,7 +275,7 @@ static esp_err_t esp_tcp_connect(const char *host, int hostlen, int port, int *s
         return ret;
     }
 
-    // Set timeout options and keep-alive options if configured
+    // Set timeout options, keep-alive options and bind device options if configured
     ret = esp_tls_set_socket_options(fd, cfg);
     if (ret != ESP_OK) {
         goto err;

components/esp-tls/esp_tls.h

@@ -172,6 +172,7 @@ typedef struct esp_tls_cfg {
     void *ds_data;                          /*!< Pointer for digital signature peripheral context */
     bool is_plain_tcp;                      /*!< Use non-TLS connection: When set to true, the esp-tls uses
                                                  plain TCP transport rather then TLS/SSL connection */
+    struct ifreq *if_name;                  /*!< The name of interface for data to go through. Use the default interface without setting */
 } esp_tls_cfg_t;
 
 #ifdef CONFIG_ESP_TLS_SERVER

components/tcp_transport/include/esp_transport_ssl.h

@@ -173,6 +173,15 @@ void esp_transport_ssl_set_psk_key_hint(esp_transport_handle_t t, const psk_hint
  */
 void esp_transport_ssl_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg);
 
+/**
+ * @brief      Set name of interface that socket can be binded on
+ *             So the data can transport on this interface
+ *
+ * @param[in]  t        The transport handle
+ * @param[in]  if_name  The interface name
+ */
+void esp_transport_ssl_set_interface_name(esp_transport_handle_t t, struct ifreq *if_name);
+
 #ifdef __cplusplus
 }
 #endif

components/tcp_transport/include/esp_transport_tcp.h

@@ -16,6 +16,7 @@
 #define _ESP_TRANSPORT_TCP_H_
 
 #include "esp_transport.h"
+#include <sys/socket.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -30,6 +31,15 @@ extern "C" {
  */
 void esp_transport_tcp_set_keep_alive(esp_transport_handle_t t, esp_transport_keep_alive_t *keep_alive_cfg);
 
+/**
+ * @brief      Set name of interface that socket can be binded on
+ *             So the data can transport on this interface
+ *
+ * @param[in]  t        The transport handle
+ * @param[in]  if_name  The interface name
+ */
+void esp_transport_tcp_set_interface_name(esp_transport_handle_t t, struct ifreq *if_name);
+
 /**
  * @brief      Create TCP transport, the transport handle must be release esp_transport_destroy callback
  *

components/tcp_transport/transport_ssl.c

@@ -345,6 +345,12 @@ void esp_transport_ssl_set_keep_alive(esp_transport_handle_t t, esp_transport_ke
     ssl->cfg.keep_alive_cfg = (tls_keep_alive_cfg_t *) keep_alive_cfg;
 }
 
+void esp_transport_ssl_set_interface_name(esp_transport_handle_t t, struct ifreq *if_name)
+{
+    GET_SSL_FROM_TRANSPORT_OR_RETURN(ssl, t);
+    ssl->cfg.if_name = if_name;
+}
+
 esp_transport_handle_t esp_transport_ssl_init(void)
 {
     esp_transport_handle_t t = esp_transport_init();
@@ -378,3 +384,8 @@ void esp_transport_tcp_set_keep_alive(esp_transport_handle_t t, esp_transport_ke
 {
     return esp_transport_ssl_set_keep_alive(t, keep_alive_cfg);
 }
+
+void esp_transport_tcp_set_interface_name(esp_transport_handle_t t, struct ifreq *if_name)
+{
+    return esp_transport_ssl_set_interface_name(t, if_name);
+}