+/*
+ * Callback for interface changes.
+ *
+ * iface is a pointer to the name of the interface.
+ *
+ * up is 1 if the interface is up, 0 if it's down.
+ *
+ * XXX - we really want "gone", not "down", where "gone" may include
+ * "down" if the OS requires an interface to be up in order to start
+ * a capture on it (as is the case in Linux and in OS X prior to
+ * Lion), but should also include *gone*, as in "there is no longer
+ * an interface with this name, so it's neither down nor up".
+ *
+ * We also may want other events, such as address changes, so what
+ * we might want is "add", "remove", and "modify" as the events.
+ */