diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index ca3f9cc..61c425c 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -1077,4 +1077,6 @@
 
 
 void mbedtls_ssl_set_timer( mbedtls_ssl_context *ssl, uint32_t millisecs );
+int mbedtls_ssl_check_timer( mbedtls_ssl_context *ssl );
+
 #endif /* ssl_internal.h */