-/* If the composed actions may be applied to any packet in the given 'flow',
- * returns true. Otherwise, the actions should only be applied to 'packet', or
- * not at all, if 'packet' was NULL. */
+/* Determines whether packets in 'flow' within 'br' should be forwarded or
+ * dropped. Returns true if they may be forwarded, false if they should be
+ * dropped.
+ *
+ * If 'have_packet' is true, it indicates that the caller is processing a
+ * received packet. If 'have_packet' is false, then the caller is just
+ * revalidating an existing flow because configuration has changed. Either
+ * way, 'have_packet' only affects logging (there is no point in logging errors
+ * during revalidation).
+ *
+ * Sets '*in_portp' to the input port. This will be a null pointer if
+ * flow->in_port does not designate a known input port (in which case
+ * is_admissible() returns false).
+ *
+ * When returning true, sets '*vlanp' to the effective VLAN of the input
+ * packet, as returned by flow_get_vlan().
+ *
+ * May also add tags to '*tags', although the current implementation only does
+ * so in one special case.
+ */