Add note about not implementing PSK id_hint

include/mbedtls/ssl.h

@@ -1614,6 +1614,11 @@ int mbedtls_ssl_conf_own_cert( mbedtls_ssl_config *conf,
  * \note           This is mainly useful for clients. Servers will usually
  *                 want to use \c mbedtls_ssl_conf_psk_cb() instead.
  *
+ * \note           Currently clients can only register one pre-shared key.
+ *                 In other words, the servers' idendity hint is ignored.
+ *                 Please contact us if you need ability to set multiple PSKs
+ *                 on clients and select one based on the identity hint.
+ *
  * \param conf     SSL configuration
  * \param psk      pointer to the pre-shared key
  * \param psk_len  pre-shared key length

library/ssl_cli.c

@@ -1981,8 +1981,11 @@ static int ssl_parse_server_psk_hint( mbedtls_ssl_context *ssl,
         return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
     }
 
-    // TODO: Retrieve PSK identity hint and callback to app
-    //
+    /*
+     * Note: we currently ignore the PKS identity hint, as we only allow one
+     * PSK to be provisionned on the client. This could be changed later if
+     * someone needs that feature.
+     */
     *p += len;
     ret = 0;
 

library/ssl_srv.c

@@ -2718,7 +2718,8 @@ static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
     if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
         ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
     {
-        /* TODO: Support identity hints */
+        /* Note: we don't support identity hints, until someone asks
+         * for them. */
         *(p++) = 0x00;
         *(p++) = 0x00;