- * helper, followed by a @const tunnel_ops *@ referring to the tunnel driver
- * of interest. The server responds with a sequence of @PS_TRACE@ and/or
- * @PS_WARN@ messages, followed by either a @PS_TUNFD@ carrying a file
- * descriptor, or a @PS_TUNERR@ followed by an integer @errno@ code.
+ * helper, followed by a strin naming the tunnel driver of interest. The
+ * server responds with a sequence of @PS_TRACE@ and/or @PS_WARN@ messages,
+ * followed by either a @PS_TUNFD@ carrying a file descriptor, or a
+ * @PS_TUNERR@ followed by an integer @errno@ code.
+ *
+ * Simple data items are sent as native representations. A string is sent as
+ * a @size_t@ giving the string's length in bytes followed by that many
+ * characters. There is no padding for alignment.