673aa5deac
Sometimes tls_do_bio() might be called when there is no new data to process (most notably, when resuming reads), in such a case internal TLS session state will remain untouched and old value in 'errno' will alter the result of SSL_get_error() call, possibly making it to return SSL_ERROR_SYSCALL. This value will be treated as an error, and will lead to closing the connection, which is not what expected.