diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 9fc8041..f070b0f 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -156,6 +156,15 @@
 
     return( 0 );
 }
+
+int mbedtls_ssl_write_hostname_ext( mbedtls_ssl_context *ssl,
+                                    unsigned char *buf,
+                                    const unsigned char *end,
+                                    size_t *olen )
+{
+    return ssl_write_hostname_ext( ssl, buf, end, olen );
+}
+
 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)