Jason Andryuk wrote:
> On Tue, Jun 22, 2010 at 10:51 AM, Sebastian Smolorz
>
> <Sebastian.Smolorz@xxxxxx> wrote:
> > Fix authentication process of wireless driver at76c50x-usb.c which was
> > broken since kernel 2.6.31
>
> Thanks for working on this, but unfortunately it does not work with my
> Linksys WUSB11.
Thanks for testing the patch.
> Does it work for you?
It does but I must admit that I did not test the direct probing, only the
authentication.
Which kernel version did you patch?
>
> [ 168.420082] usb 4-1: new full speed USB device using uhci_hcd and
> address 2 [ 168.719582] Atmel at76x USB Wireless LAN Driver 0.17
> loading
> [ 168.743011] usb 4-1: using firmware atmel_at76c503-i3861.bin
> (version 0.90.0-44)
> [ 168.746784] phy1: Selected rate control algorithm 'minstrel'
> [ 168.747410] phy1: USB 4-1:1.0, MAC 00:06:25:00:6a:7a, firmware
> 0.90.0-2 [ 168.747413] phy1: regulatory domain 0x10: FCC (USA)
> [ 168.747434] usbcore: registered new interface driver at76c50x-usb
> [ 168.803980] udev: renamed network interface wlan0 to wlan3
> [ 168.837883] ADDRCONF(NETDEV_UP): wlan3: link is not ready
> [ 274.423484] wlan3: direct probe to 00:13:46:08:8a:6e (try 1)
> [ 274.622558] wlan3: direct probe to 00:13:46:08:8a:6e (try 2)
> [ 274.822600] wlan3: direct probe to 00:13:46:08:8a:6e (try 3)
> [ 275.022557] wlan3: direct probe to 00:13:46:08:8a:6e timed out
> [ 284.694487] wlan3: direct probe to 00:13:46:08:8a:6e (try 1)
> [ 284.900075] wlan3: direct probe to 00:13:46:08:8a:6e (try 2)
> [ 285.105548] wlan3: direct probe to 00:13:46:08:8a:6e (try 3)
> [ 285.302565] wlan3: direct probe to 00:13:46:08:8a:6e timed out
> [ 294.954450] wlan3: direct probe to 00:13:46:08:8a:6e (try 1)
> [ 295.152564] wlan3: direct probe to 00:13:46:08:8a:6e (try 2)
> [ 295.352559] wlan3: direct probe to 00:13:46:08:8a:6e (try 3)
> [ 295.552556] wlan3: direct probe to 00:13:46:08:8a:6e timed out
>
> > + /* The following code lines are important when the device is
> > going to + * authenticate with a new bssid. The driver must
> > send CMD_JOIN before + * an authentication frame is
> > transmitted. For this to succeed, the + * correct bssid of the
> > AP must be known. As mac80211 does not inform + * drivers about
> > the bssid prior to the authentication process the + * following
> > workaround is necessary. If the TX frame is an + *
> > authentication frame extract the bssid and send the CMD_JOIN. */ +
> > if (mgmt->frame_control & cpu_to_le16(IEEE80211_STYPE_AUTH)) { +
> > if (compare_ether_addr(priv->bssid, mgmt->bssid)) { +
> > memcpy(priv->bssid, mgmt->bssid, ETH_ALEN); +
> > ieee80211_queue_work(hw, &priv->work_join_bssid); +
> > return NETDEV_TX_BUSY;
> > + }
> > + }
> > +
>
> The check for IEEE80211_STYPE_AUTH may be insufficient since direct
> probe is sent with frame control IEEE80211_STYPE_PROBE_REQ. Maybe a
> better check would be comparing struct ieee80211_work.type to
> IEEE80211_WORK_DIRECT_PROBE or IEEE80211_WORK_AUTH? I am not sure if
> that is accessible in the driver's tx function though.
No, it's not accessible by the driver.
>
> With the frame_control check modified for either IEEE80211_STYPE_AUTH
> or IEEE80211_STYPE_PROBE_REQ, it is still unsuccessful.
> at76_work_join_bssid is called between the first and second direct
> probe attempt. However, the CMD_JOIN command is not in the log.
> Presumably that occurs because the BSSID pulled from the PROBE_REQ is
> ff:ff:ff:ff:ff:ff which fails the is_valid_ether_addr(priv->bssid)
> check in at76_work_join_bssid.
The problem is that when probed directly, no (real) bssid is coded in the
frame, only the multicast address. So with a frame of type
IEEE80211_STYPE_PROBE_REQ we have no chance to decode the bssid because
mac80211 doesn't give us the needed information. I think in the case of
direct probing we are lost, only the authentication works with the patch I
sent. Another solution would be to change mac80211 but that would be a
special solution for just one driver. It's questionable if this is a viable
way. On the other hand it would be great to have a working driver again.
--
Sebastian
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