Em Terça-feira 10 Março 2009, às 04:13:34, Johannes Berg escreveu:
> On Mon, 2009-03-09 at 18:50 -0300, Herton Ronaldo Krzesinski wrote:
> > I have the problem when using 2.6.29 and judging by the code the situation
> > stays the same with wireless-testing, even after the fix "mac80211: deauth when
> > interface is marked down" (the fix doesn't work with kernel 2.6.28 or later, as
> > I'll explain).
> >
> > The problem is, with latest kernels wpa_supplicant isn't still notified when
> > interface goes down, even after commit "mac80211: deauth when interface is
> > marked down" (e327b847 on Linus tree). There isn't a problem with this commit,
> > but because of other code changes it doesn't work on latest kernels (but works
> > if I apply same/similar change on 2.6.27 for example).
> >
> > The issue is as follows: after commit "mac80211: restructure disassoc/deauth
> > flows" in 2.6.28, the call to ieee80211_sta_deauthenticate added by commit
> > e327b847 will not work: because we do sta_info_flush(local, sdata); inside
> > ieee80211_stop (iface.c), all stations in interface are cleared, so when calling
> > ieee80211_sta_deauthenticate->ieee80211_set_disassoc (mlme.c), inside
> > ieee80211_set_disassoc we have this in the beginning:
> >
> > sta = sta_info_get(local, ifsta->bssid);
> > if (!sta) {
> >
> > the !sta check triggers, so the function returns early and
> > ieee80211_sta_send_apinfo(sdata, ifsta); later isn't called, so wpa_supplicant
> > isn't notified with SIOCGIWAP
>
> Interesting problem.
>
> > One possible fix is moving sta_info_flush, to avoid !sta, and seems good, like
> > the following:
> >
> > diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
> > index 2acc416..0929581 100644
> > --- a/net/mac80211/iface.c
> > +++ b/net/mac80211/iface.c
> > @@ -370,25 +370,6 @@ static int ieee80211_stop(struct net_device *dev)
> > rcu_read_unlock();
> >
> > /*
> > - * Remove all stations associated with this interface.
> > - *
> > - * This must be done before calling ops->remove_interface()
> > - * because otherwise we can later invoke ops->sta_notify()
> > - * whenever the STAs are removed, and that invalidates driver
> > - * assumptions about always getting a vif pointer that is valid
> > - * (because if we remove a STA after ops->remove_interface()
> > - * the driver will have removed the vif info already!)
> > - *
> > - * We could relax this and only unlink the stations from the
> > - * hash table and list but keep them on a per-sdata list that
> > - * will be inserted back again when the interface is brought
> > - * up again, but I don't currently see a use case for that,
> > - * except with WDS which gets a STA entry created when it is
> > - * brought up.
> > - */
> > - sta_info_flush(local, sdata);
> > -
> > - /*
> > * Don't count this interface for promisc/allmulti while it
> > * is down. dev_mc_unsync() will invoke set_multicast_list
> > * on the master interface which will sync these down to the
> > @@ -539,6 +520,26 @@ static int ieee80211_stop(struct net_device *dev)
> > conf.mac_addr = dev->dev_addr;
> > /* disable all keys for as long as this netdev is down */
> > ieee80211_disable_keys(sdata);
> > +
> > + /*
> > + * Remove all stations associated with this interface.
> > + *
> > + * This must be done before calling ops->remove_interface()
> > + * because otherwise we can later invoke ops->sta_notify()
> > + * whenever the STAs are removed, and that invalidates driver
> > + * assumptions about always getting a vif pointer that is valid
> > + * (because if we remove a STA after ops->remove_interface()
> > + * the driver will have removed the vif info already!)
> > + *
> > + * We could relax this and only unlink the stations from the
> > + * hash table and list but keep them on a per-sdata list that
> > + * will be inserted back again when the interface is brought
> > + * up again, but I don't currently see a use case for that,
> > + * except with WDS which gets a STA entry created when it is
> > + * brought up.
> > + */
> > + sta_info_flush(local, sdata);
> > +
> > local->ops->remove_interface(local_to_hw(local), &conf);
> > }
> >
> > My question is, is the patch above safe? that is, do we need to always
> > call sta_info_flush on interface down like currently, or just for the case we
> > call remove_interface, like the comment states? if the latter, patch above
> > is good, and solves the wpa_supplicant/userspace issue.
>
> The comment states it must be before remove_interface, not that it
> doesn't need to be called unless that is called, and this code moving is
> incorrect for AP_VLAN devices.
>
> You could move the disassoc part out of the switch to before this.
Ok, here is the new patch, if it's ok please apply (I can resubmit with patch
in subject/standalone message if necessary):
>From eb6f79597b9e6af8a3618873a781fd6ebcbd50a0 Mon Sep 17 00:00:00 2001
From: Herton Ronaldo Krzesinski <herton@xxxxxxxxxxxxxxx>
Date: Tue, 10 Mar 2009 09:44:17 -0300
Subject: [PATCH] mac80211: deauth before flushing STA information
Even after commit "mac80211: deauth when interface is marked down"
(e327b847 on Linus tree), userspace still isn't notified when interface
goes down. There isn't a problem with this commit, but because of other
code changes it doesn't work on kernels >= 2.6.28 (works if same/similar
change applied on 2.6.27 for example).
The issue is as follows: after commit "mac80211: restructure disassoc/deauth
flows" in 2.6.28, the call to ieee80211_sta_deauthenticate added by
commit e327b847 will not work: because we do sta_info_flush(local, sdata)
inside ieee80211_stop (iface.c), all stations in interface are cleared, so
when calling ieee80211_sta_deauthenticate->ieee80211_set_disassoc (mlme.c),
inside ieee80211_set_disassoc we have this in the beginning:
sta = sta_info_get(local, ifsta->bssid);
if (!sta) {
The !sta check triggers, thus the function returns early and
ieee80211_sta_send_apinfo(sdata, ifsta) later isn't called, so
wpa_supplicant/userspace isn't notified with SIOCGIWAP.
This commit moves deauthentication to before flushing STA info
(sta_info_flush), thus the above can't happen and userspace is really
notified when interface goes down.
Signed-off-by: Herton Ronaldo Krzesinski <herton@xxxxxxxxxxxxxxx>
---
net/mac80211/iface.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 2acc416..f9f27b9 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -370,6 +370,18 @@ static int ieee80211_stop(struct net_device *dev)
rcu_read_unlock();
/*
+ * Announce that we are leaving the network, in case we are a
+ * station interface type. This must be done before removing
+ * all stations associated with sta_info_flush, otherwise STA
+ * information will be gone and no announce being done.
+ */
+ if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+ if (sdata->u.mgd.state != IEEE80211_STA_MLME_DISABLED)
+ ieee80211_sta_deauthenticate(sdata,
+ WLAN_REASON_DEAUTH_LEAVING);
+ }
+
+ /*
* Remove all stations associated with this interface.
*
* This must be done before calling ops->remove_interface()
@@ -454,10 +466,6 @@ static int ieee80211_stop(struct net_device *dev)
netif_addr_unlock_bh(local->mdev);
break;
case NL80211_IFTYPE_STATION:
- /* Announce that we are leaving the network. */
- if (sdata->u.mgd.state != IEEE80211_STA_MLME_DISABLED)
- ieee80211_sta_deauthenticate(sdata,
- WLAN_REASON_DEAUTH_LEAVING);
memset(sdata->u.mgd.bssid, 0, ETH_ALEN);
del_timer_sync(&sdata->u.mgd.chswitch_timer);
del_timer_sync(&sdata->u.mgd.timer);
--
1.6.2
>
> johannes
>
--
[]'s
Herton
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