tls13:hrr:add empty frame work

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 775443c..c1ab3ce 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1277,6 +1277,16 @@
 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
 
 /*
+ * Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST
+ */
+
+static int ssl_tls13_write_hello_retry_request( mbedtls_ssl_context *ssl )
+{
+    ((void) ssl);
+    return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+}
+
+/*
  * TLS 1.3 State Machine -- server side
  */
 int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
@@ -1311,6 +1321,7 @@
             ret = ssl_tls13_write_server_hello( ssl );
             break;
 
+<<<<<<< HEAD
         case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS:
             ret = ssl_tls13_write_encrypted_extensions( ssl );
             if( ret != 0 )
@@ -1318,6 +1329,10 @@
                 MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_encrypted_extensions", ret );
                 return( ret );
             }
+=======
+        case MBEDTLS_SSL_HELLO_RETRY_REQUEST:
+            ret = ssl_tls13_write_hello_retry_request( ssl );
+>>>>>>> tls13:hrr:add empty frame work
             break;
 
 #if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)