Re: [RFC] nl80211: Allow GET_INTERFACE dumps to be filtered

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2016-06-30 at 19:51 -0500, Denis Kenzior wrote:
> This patch allows GET_INTERFACE dumps to be filtered based on
> NL80211_ATTR_WIPHY or NL80211_ATTR_WDEV.  The documentation for
> GET_INTERFACE mentions that this is possible:
> "Request an interface's configuration; either a dump request on
> a %NL80211_ATTR_WIPHY or ..."
> 
> However, this behavior has not been implemented until now.
> ---
>  net/wireless/nl80211.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 244d552..24cb4d9 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -2515,15 +2515,47 @@ static int nl80211_send_iface(struct sk_buff
> *msg, u32 portid, u32 seq, int flag
>  	return -EMSGSIZE;
>  }
>  
> +static int nl80211_dump_interface_parse(struct sk_buff *skb,
> +				    struct netlink_callback *cb,
> +				    int *filter_wiphy)
> +{
> +	struct nlattr **tb = nl80211_fam.attrbuf;
> +	int ret = nlmsg_parse(cb->nlh, GENL_HDRLEN +
> nl80211_fam.hdrsize,
> +			      tb, nl80211_fam.maxattr,
> nl80211_policy);
> +	/* ignore parse errors for backward compatibility */
> +	if (ret)
> +		return 0;
> +
> +	if (tb[NL80211_ATTR_WIPHY])
> +		*filter_wiphy = nla_get_u32(tb[NL80211_ATTR_WIPHY]);
> +	if (tb[NL80211_ATTR_WDEV])
> +		*filter_wiphy = nla_get_u64(tb[NL80211_ATTR_WDEV])
> >> 32;

The whole ret thing seems a bit pointless since you check the tb[], but
I guess it's better to be explicit.

Looks fine.

johannes