[PATCH v3] nl80211: specify RSSI threshold in scheduled scan

[PATCH v3] nl80211: specify RSSI threshold in scheduled scan

[Thomas Pedersen]

Support configuring an RSSI threshold in dBm (s32) when requesting
scheduled scan, below which a BSS won't be reported by the cfg80211
driver.

Signed-off-by: Thomas Pedersen <c_tpeder@qca.qualcomm.com>

---

v2:
	naming (Kalle)
	remove WIPHY_FLAG (Kalle)
	use sched_scan_match_attr (Luca)

v3:
	nl80211 API names (Holger)
	misc. / typos (Johannes)

 include/linux/nl80211.h |    3 +++
 include/net/cfg80211.h  |    2 ++
 net/wireless/nl80211.c  |    6 +++++-
 3 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 970afdf..93e13f7 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1956,6 +1956,8 @@ enum nl80211_reg_rule_attr {
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_INVALID: attribute number 0 is reserved
  * @NL80211_SCHED_SCAN_MATCH_ATTR_SSID: SSID to be used for matching,
  * only report BSS with matching SSID.
+ * @NL80211_SCHED_SCAN_MATCH_ATTR_RSSI: RSSI threshold (in dBm) for reporting a
+ *	BSS in scan results. Filtering is turned off if not specified.
  * @NL80211_SCHED_SCAN_MATCH_ATTR_MAX: highest scheduled scan filter
  *	attribute number currently defined
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST: internal use
@@ -1964,6 +1966,7 @@ enum nl80211_sched_scan_match_attr {
 	__NL80211_SCHED_SCAN_MATCH_ATTR_INVALID,
 
 	NL80211_ATTR_SCHED_SCAN_MATCH_SSID,
+	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI,
 
 	/* keep last */
 	__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7319f25..55a9d24 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -975,6 +975,7 @@ struct cfg80211_match_set {
  * @wiphy: the wiphy this was for
  * @dev: the interface
  * @channels: channels to scan
+ * @rssi_thold: don't report scan results below this threshold (in s32 dBm)
  */
 struct cfg80211_sched_scan_request {
 	struct cfg80211_ssid *ssids;
@@ -985,6 +986,7 @@ struct cfg80211_sched_scan_request {
 	size_t ie_len;
 	struct cfg80211_match_set *match_sets;
 	int n_match_sets;
+	s32 rssi_thold;
 
 	/* internal */
 	struct wiphy *wiphy;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 7ae54b8..629e72c 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -252,6 +252,7 @@ static const struct nla_policy
 nl80211_match_policy[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1] = {
 	[NL80211_ATTR_SCHED_SCAN_MATCH_SSID] = { .type = NLA_BINARY,
 						 .len = IEEE80211_MAX_SSID_LEN },
+	[NL80211_SCHED_SCAN_MATCH_ATTR_RSSI] = { .type = NLA_U32 },
 };
 
 /* ifidx get helper */
@@ -4241,7 +4242,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 		nla_for_each_nested(attr,
 				    info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH],
 				    tmp) {
-			struct nlattr *ssid;
+			struct nlattr *ssid, *rssi;
 
 			nla_parse(tb, NL80211_SCHED_SCAN_MATCH_ATTR_MAX,
 				  nla_data(attr), nla_len(attr),
@@ -4257,6 +4258,9 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 				request->match_sets[i].ssid.ssid_len =
 					nla_len(ssid);
 			}
+			rssi = tb[NL80211_SCHED_SCAN_MATCH_ATTR_RSSI];
+			if (rssi)
+				request->rssi_thold = nla_get_u32(rssi);
 			i++;
 		}
 	}
-- 
1.7.4.1

Re: [PATCH v3] nl80211: specify RSSI threshold in scheduled scan

[Johannes Berg]

On Tue, 2012-06-19 at 10:33 -0700, Thomas Pedersen wrote:
> Support configuring an RSSI threshold in dBm (s32) when requesting
> scheduled scan, below which a BSS won't be reported by the cfg80211
> driver.

> @@ -4241,7 +4242,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
>  		nla_for_each_nested(attr,
>  				    info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH],
>  				    tmp) {
> -			struct nlattr *ssid;
> +			struct nlattr *ssid, *rssi;
>  
>  			nla_parse(tb, NL80211_SCHED_SCAN_MATCH_ATTR_MAX,
>  				  nla_data(attr), nla_len(attr),
> @@ -4257,6 +4258,9 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
>  				request->match_sets[i].ssid.ssid_len =
>  					nla_len(ssid);
>  			}
> +			rssi = tb[NL80211_SCHED_SCAN_MATCH_ATTR_RSSI];
> +			if (rssi)
> +				request->rssi_thold = nla_get_u32(rssi);

I was going to apply this, but then I realized ... if userspace doesn't
set the value then the default is 0 which is a bit useless, better set
to a very small negative value or something, right?

johannes

Re: [PATCH v3] nl80211: specify RSSI threshold in scheduled scan

[Pedersen, Thomas]

On Wed, Jun 20, 2012 at 10:26:59AM +0200, Johannes Berg wrote:
> On Tue, 2012-06-19 at 10:33 -0700, Thomas Pedersen wrote:
> > Support configuring an RSSI threshold in dBm (s32) when requesting
> > scheduled scan, below which a BSS won't be reported by the cfg80211
> > driver.
> 
> > @@ -4241,7 +4242,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
> >  		nla_for_each_nested(attr,
> >  				    info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH],
> >  				    tmp) {
> > -			struct nlattr *ssid;
> > +			struct nlattr *ssid, *rssi;
> >  
> >  			nla_parse(tb, NL80211_SCHED_SCAN_MATCH_ATTR_MAX,
> >  				  nla_data(attr), nla_len(attr),
> > @@ -4257,6 +4258,9 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
> >  				request->match_sets[i].ssid.ssid_len =
> >  					nla_len(ssid);
> >  			}
> > +			rssi = tb[NL80211_SCHED_SCAN_MATCH_ATTR_RSSI];
> > +			if (rssi)
> > +				request->rssi_thold = nla_get_u32(rssi);
> 
> I was going to apply this, but then I realized ... if userspace doesn't
> set the value then the default is 0 which is a bit useless, better set
> to a very small negative value or something, right?

OK. I was still treating the '0' threshold as "off" in the driver, but
this is more consistent. Will submit a v4 shortly.

Thanks,
Thomas