On 1/30/24 01:05, Johannes Berg wrote:
From: Johannes Berg <johannes.berg@xxxxxxxxx>
This could be used e.g. for temporarily sending quiet
(mode=1 in CSA/ECSA), or updating bandwidth. This is
I know the intent here (from the other thread), but using the phrase _or
updating bandwidth_ is probably not correct since currently without this
change also, just changing the bandwidth is possible, isn't it?
In the chandef identical check we have -
return (chandef1->chan == chandef2->chan &&
chandef1->width == chandef2->width && ....
``````````````````````````````````
So the width would not match hence false would be returned.
Also, bringing a part of the discussion we had in the other thread -
>>> I'm thinking about removing that identical() check entirely - you
>>> might want to switch to the same channel with quiet=1. At least for
>>> testing that'd be really useful, and I don't think it really serves
>>> any purpose to forbid it.
>
>> Yeah, we can do. But is there any actual use case? Also, what if some
>> notorious user space application simply sends NL command without even
>> quiet=1? There should be some check I guess?
>
> I'm not sure we care much about a broken userspace application running
> with root privileges breaking something here? :-)
>
> And at least for testing it's very useful to be able to do that. Agree
> that identical channel and quiet==0 doesn't make _sense_, but even
> then I'm not sure there's a lot of value in not permitting it. With
> quiet==1 at least it does make some sense still though, and we're
> currently not allowing it, hence my patch (to be able to test
> scenarios like that we saw elsewhere.)
Agreed to your point. So in that case, should we skip the identical
check only when quiet=1?
also useful for testing, since it's something that an
AP may do and the client needs to be prepared. Simply
allow it.
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/mac80211/cfg.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8f647e28e354..c92acbf7b002 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3874,10 +3874,6 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
if (sdata->wdev.cac_started)
return -EBUSY;
- if (cfg80211_chandef_identical(&chanreq.oper,
- &sdata->vif.bss_conf.chanreq.oper))
- return -EINVAL;
-
if (chanreq.oper.punctured && !sdata->vif.bss_conf.eht_support)
return -EINVAL;
