nl80211: add new scan flag to indicate P2P search

Scan request (NL80211_CMD_TRIGGER_SCAN) is used for triggering both scan and P2P search.
At driver/firmware layer, scan and P2P search might be handled differently.

Add new scan flag to indicate P2P search. This flag can be used by applications (e.g. wpa_supplicant) to explicitly request P2P search.

---
 include/uapi/linux/nl80211.h | 2 ++
 1 file changed, 2 insertions(+)

index f52797a..d7d07d6 100644
@@ -4383,12 +4383,14 @@ enum nl80211_connect_failed_reason {
  *	locally administered 1, multicast 0) is assumed.
  *	This flag must not be requested when the feature isn't supported, check
  *	the nl80211 feature flags for the device.
+ * @NL80211_SCAN_FLAG_P2P: indicate this is a request for a P2P search
  */
 enum nl80211_scan_flags {
 	NL80211_SCAN_FLAG_LOW_PRIORITY			= 1<<0,
 	NL80211_SCAN_FLAG_FLUSH				= 1<<1,
 	NL80211_SCAN_FLAG_AP				= 1<<2,
 	NL80211_SCAN_FLAG_RANDOM_ADDR			= 1<<3,
+	NL80211_SCAN_FLAG_P2P				= 1<<4,
 };
 
 /**

1.9.1

I think this ship has sailed many months ago -- too late, you can never rely on wpa_supplicant settings this flag.

If you need to distinguish, you should be able to advertise P2P-Device supports, and then get P2P scans on the P2P-Device virtual interface. Could be a pure driver thing of course.

johannes

I'm not sure I'd fully agree with that.. wpa_supplicant currently maps its internal struct wpa_driver_scan_params::p2p_probe to NL80211_ATTR_TX_NO_CCK_RATE (and also removal of CCK rates from NL80211_ATTR_SCAN_SUPP_RATES). However, neither of these make much sense in bands other than 2.4 GHz. There is ongoing effort in defining P2P social channels on other bands and it would be useful to be prepared for those with a clear nl80211 flag in scan parameters. P2P on those new bands will require wpa_supplicant changes, so it is reasonable to assume that a wpa_supplicant version that supports those bands will also support this new flag.

It would be unfortunate to force people to use P2P-Device for this.

Jouni Malinen                                            PGP id EFC895FA

Hi Johannes,

Following Jouni's comment, would you please re-consider?

Thanks,
Dedy.

From: Jouni Malinen [mailto:[email protected]]
Sent: Monday, January 26, 2015 11:58 AM

differently.

internal struct wpa_driver_scan_params::p2p_probe to NL80211_ATTR_TX_NO_CCK_RATE (and also removal of CCK rates from NL80211_ATTR_SCAN_SUPP_RATES). However, neither of these make much sense in bands other than 2.4 GHz. There is ongoing effort in defining P2P social channels on other bands and it would be useful to be prepared for those with a clear nl80211 flag in scan parameters. P2P on those new bands will require wpa_supplicant changes, so it is reasonable to assume that a wpa_supplicant version that supports those bands will also support this new flag.

Just for the record - we discussed this in Ottawa and as I understood it you seemed not to object as much to P2P-Device as here originally.

In particular, we discussed the fact that P2P-Device can share MAC addresses with the regular interface, but also from a 'foreign' interface (i.e. a different NIC supporting e.g. different bands).

I'll drop all of this for now, at least until you investigate P2P-Device support more thoroughly.

johannes