On Mon, 2011-08-08 at 10:37 +0200, Johannes Berg wrote: > On Tue, 2011-08-02 at 18:10 -0400, Pavel Roskin wrote: > > > > Both of those commands result in libertas being called with > > > cfg80211_scan_request with n_ssids=1 and the "test" SSID present in > > > cfg80211_scan_request.ssids[0], as expected. > > > > > > > > > iwlist eth0 scan > > > iw dev eth0 scan > > > > > > Both of those commands result in libertas being called with > > > cfg80211_scan_request with n_ssids=1 and a zero-length SSID present in > > > cfg80211_scan_request.ssids[0]. > > > Is this a bug? I would expect it to be passed n_ssids=0 in this case. > > > > I believe n_ssids is the number of probe requests to be sent per > > channel. It scanning for all SSIDs, one probe request is sent. It is > > only for passive scanning that we don't need any probes. > > Yeah. "iw dev eth0 scan passive" will cause n_ssids to be 0. I think the question was slightly different. As I understand, Daniel wants to know why the n_ssids is 1 even if no SSID is passed from user space. A zero-length SSID is a broadcast SSID. So probe requests *will* be sent, but with the broadcast SSID. If you explicitly ask for a passive scan (as Johannes mentioned), then n_ssids will be 0 which means that no probe requests should be sent at all. The n_ssids field is the number of *different* probe_reqs that will be sent per channel. Some drivers will send more than one probe_req with the same SSID per channel (eg. wl12xx sends 2 probe_reqs per SSID on each channel). -- Cheers, Luca. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
