Re: [RFC] add nl80211

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2006-08-24 at 19:27 +0200, Thomas Graf wrote:

> I'd use normal u32 attributes here as well and simply
> enumerate their type 1..n.
> 
> 	int idx = 1
> 	list_for_each_entry(drv, &nl80211_drv_list, list)
> 		NLA_PUT_U32(msg, idx++, drv->wiphy);
> 
> The additional header seems waste but this way you stay flexible
> and can extend the protocol later on. Attribute lengths are
> checked with an open end in mind, i.e. you can put more stuff
> behind that u32 in the future and your old applications will
> still work.
> 
> You also might want to consider returning ifindex and
> the associated name.

That'd be a list of ifindexes again...

> > +static int nl80211_get_intfs(struct sk_buff *skb, struct genl_info *info)

> Try not to reuse the same attribute type for different purposes,
> it will force you to duplicate the validation policy for every
> single command and things become very error prone.

I completely reworked that now so it will:
 * create a nested NL80211_ATTR_INTERFACE_LIST with nested {
   * 1..N attributes, with nested {
     * ATTR_IFINDEX and
     * ATTR_IFNAME
   }
 }

how does that sound? Maybe I should do the same for the WIPHY list? i.e.
create a new type ATTR_WIPHY_LIST and within that nest numbered
attributes (array indexes) and in there put ATTR_WIPHY? So possibly I
could also put ATTR_INTERFACE_LIST in there as well later?

johannes