mac80211/iwlwifi + hidden ssids

Hello,
I am unable to connect to a dynamic wep network with hidden ssid using iwl3945 and the lastest fedora 7 kernel (which should have very recent stuff). The problem is that the card never finds the ap. Running wpa_supplicant directly shows "Got scan results xxx bytes" (can't

remeber the exact message).
While with ipw3945d + ieee80211 it works fine. (NetworkManager does not connect either see http://bugzilla.gnome.org/show_bug.cgi?id=464215 ). I haven't tryed the suggestion there yet because I am not near the network right now.
Any idea whats wrong? Does it work for anybody (maybe with other mac80211 drivers)
Currently I am not sure whom to blame iwl3945 or mac80211 or both.

Quoted 5 lines · dragoran

Hello,
I am unable to connect to a dynamic wep network with hidden ssid using iwl3945 and the lastest fedora 7 kernel (which should have very recent stuff). The problem is that the card never finds the ap. Running wpa_supplicant directly shows "Got scan results xxx bytes" (can't

Quoted 8 lines

remeber the exact message).
While with ipw3945d + ieee80211 it works fine. (NetworkManager does not connect either see http://bugzilla.gnome.org/show_bug.cgi?id=464215 ). I haven't tryed the suggestion there yet because I am not near the network right now.
Any idea whats wrong? Does it work for anybody (maybe with other mac80211 drivers)
Currently I am not sure whom to blame iwl3945 or mac80211 or both.

Fedora 7 kernels are a little behind (1-2 weeks behind wireless-2.6) ATM, so it might be best to handle this at bugzilla.kernel.org.

F7 _does_ have the kernel patch to probe for hidden SSIDs when associating. What I've found with that patch is that manually invoking the wireless tools yields satisfactory results, but that NM (which afaik relies on wpa_supplicant) still tends to have problems.

My hunch is that wpa_supplicant (at least how NM configures it) is doing something "too smart", but I really don't know.

Do you have control over the AP? If so, can you temporarily try using static WEP or an open configuration so that you can test using iwconfig?

Quoted 4 lines · John W. Linville

Quoted 3 lines · dragoran

Hello,
I am unable to connect to a dynamic wep network with hidden ssid using iwl3945 and the lastest fedora 7 kernel (which should have very recent

Quoted 2 lines

Fedora 7 kernels are a little behind (1-2 weeks behind wireless-2.6) ATM, so it might be best to handle this at bugzilla.kernel.org.

Ok, will file a bug after collecting more data (wpa_supplicant output).

Quoted 4 lines

F7 _does_ have the kernel patch to probe for hidden SSIDs when associating. What I've found with that patch is that manually invoking the wireless tools yields satisfactory results, but that NM (which afaik relies on wpa_supplicant) still tends to have problems.

I know I also followed the thread on the nm list but it seems that I cannot even get a connection with wpa_supplicant started by hand.

the wpa_supplicant.conf I tryed:
-----------

# this driver requires ap_scan=2 mode when using hidden SSIDs
# request driver to take care of AP selection and roaming
ap_scan=2

the exact same config works with the old stack.... should I try to change the ap_scan value to 1 ?

Quoted 5 lines · dragoran

Hello,
I am unable to connect to a dynamic wep network with hidden ssid using iwl3945 and the lastest fedora 7 kernel (which should have very recent stuff). The problem is that the card never finds the ap. Running wpa_supplicant directly shows "Got scan results xxx bytes" (can't

Quoted 8 lines

remeber the exact message).
While with ipw3945d + ieee80211 it works fine. (NetworkManager does not connect either see http://bugzilla.gnome.org/show_bug.cgi?id=464215 ). I haven't tryed the suggestion there yet because I am not near the network right now.
Any idea whats wrong? Does it work for anybody (maybe with other mac80211 drivers)
Currently I am not sure whom to blame iwl3945 or mac80211 or both.

Fedora 7 kernels are a little behind (1-2 weeks behind wireless-2.6) ATM, so it might be best to handle this at bugzilla.kernel.org.

F7 _does_ have the kernel patch to probe for hidden SSIDs when associating. What I've found with that patch is that manually invoking the wireless tools yields satisfactory results, but that NM (which afaik relies on wpa_supplicant) still tends to have problems. My hunch is that wpa_supplicant (at least how NM configures it) is doing something "too smart", but I really don't know.

Do you have control over the AP? If so, can you temporarily try using static WEP or an open configuration so that you can test using iwconfig?

Thanks,

John

[..]
wpa_supplicant's support for hidden SSIDs sort of sucks; mainly because the drivers implement this in different ways. wpa_supplicant says you must use "ap_scan=2" for hidden SSIDs (and possibly ssid_scan=1 to do specific ssid probe requests), which causes wpa_supplicant to blast all settings to the card directly and not try to be smart about AP scanning and selection. However, this doesn't work often because drivers are inconsistent about this.

The way it _should_ work is that if scan_ssid = 1 for a network, wpa_supplicant should ask that the driver scan the specific ssid using IW_SCAN_THIS_ESSID. The card would then issue specific SSID scan requests on each channel during the scan, and hopefully find the AP in question.

Unfortunately, most drivers don't support IW_SCAN_THIS_ESSID. So the best we can do is set AP_SCAN=2, let wpa_supplicant blow all the settings to the card, and just _hope_ that the card/driver are smart enough to find the hidden SSID on their own and associate. Which is less often than we'd hope.

Quoted 15 lines · Dan Williams

[..]
wpa_supplicant's support for hidden SSIDs sort of sucks; mainly because the drivers implement this in different ways. wpa_supplicant says you must use "ap_scan=2" for hidden SSIDs (and possibly ssid_scan=1 to do specific ssid probe requests), which causes wpa_supplicant to blast all settings to the card directly and not try to be smart about AP scanning and selection. However, this doesn't work often because drivers are inconsistent about this.

The way it _should_ work is that if scan_ssid = 1 for a network, wpa_supplicant should ask that the driver scan the specific ssid using IW_SCAN_THIS_ESSID. The card would then issue specific SSID scan requests on each channel during the scan, and hopefully find the AP in question.

Quoted 5 lines

Unfortunately, most drivers don't support IW_SCAN_THIS_ESSID. So the best we can do is set AP_SCAN=2, let wpa_supplicant blow all the settings to the card, and just _hope_ that the card/driver are smart enough to find the hidden SSID on their own and associate. Which is less often than we'd hope.

so your are suggestion to use ap_scan=2 and add scan_ssid=1 to the network block?
nm seems not to do this.

btw shouldn't all mac80211 drivers either work or not work because the code for this is in mac80211 and not in the drivers?

I will be able to test again this friday will try this and the ap_scan=1 if there are other suggestion feel free to say them so I can add them to my "totest" list ;)

Quoted 2 lines · dragoran

btw shouldn't all mac80211 drivers either work or not work because the code for this is in mac80211 and not in the drivers?

Yeah, pretty much; but each driver/firmware may handle hidden ssids slightly differently. mac80211 should bring some sanity to this area, but I wouldn't discount variation between even mac80211 based drivers.

Quoted 8 lines · Dan Williams

Quoted 2 lines · dragoran

btw shouldn't all mac80211 drivers either work or not work because the code for this is in mac80211 and not in the drivers?

Yeah, pretty much; but each driver/firmware may handle hidden ssids slightly differently. mac80211 should bring some sanity to this area, but I wouldn't discount variation between even mac80211 based drivers.

Hmmm...doesn't the iwlwifi firmware intercede in scanning?

Quoted 1 line · dragoran

btw shouldn't all mac80211 drivers either work or not work because

Quoted 1 line

code for this is in mac80211 and not in the drivers?

Yeah, pretty much; but each driver/firmware may handle hidden ssids slightly differently. mac80211 should bring some sanity to this area, but I wouldn't discount variation between even mac80211 based drivers.

Quoted 1 line · dragoran

btw shouldn't all mac80211 drivers either work or not work because

Quoted 1 line

code for this is in mac80211 and not in the drivers?

Yeah, pretty much; but each driver/firmware may handle hidden ssids slightly differently. mac80211 should bring some sanity to this area, but I wouldn't discount variation between even mac80211 based drivers.

Hey,

I bit more info. I am hearing it is a Cisco CCX feature and will not be included in the open source code.

Dana

Quoted 6 lines · Dana R

Hey,

I bit more info. I am hearing it is a Cisco CCX feature and will not be included in the open source code.

Dana

Huh? I'm not sure what "it" is? Care to elaborate?

I do find it dismaying to hear that Intel is holding back wireless compatibility features from Linux...

John
--
John W. Linville
[email protected]

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Quoted 6 lines · Dana R

Hey,

I bit more info. I am hearing it is a Cisco CCX feature and will not be included in the open source code.

Dana

Huh? I'm not sure what "it" is? Care to elaborate?

I do find it dismaying to hear that Intel is holding back wireless compatibility features from Linux...

John

best we can do is set AP_SCAN=2, let wpa_supplicant blow all the settings to the card, and just _hope_ that the card/driver are smart enough to find the hidden SSID on their own and associate. Which is less often than we'd hope.