[ath9k-devel] ath9k: injecting frames at a rate other than 1Mbps

[ath9k-devel] ath9k: injecting frames at a rate other than 1Mbps

[Andrew Watts]

Hi,

I am trying to inject frames at a specific rate (54 Mbps, 36 Mbps etc) but
everything seems to come out at 1Mbps.  I patched the driver with the code
found in this thread
here<http://www.mail-archive.com/ath9k-devel@lists.ath9k.org/msg02853.html>,
but frames are still transmitted at 1Mbps over the air.  I have looked at
the radiotap header for the frame I am injecting and everything seems fine
to me.  I am seeing the same issue with the packetspammer app too.  Does
anyone have a patch for this or know where I should be looking?  I have been
playing with ath_buf_set rate in xmit.c and have not had any success.

Ubuntu 9.10 - 2.6.31-19-generic-pae
Compat-wireless driver from 11-30-2009 (should I upgrade to the latest?)

Thanks in advance.

Andrew
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[ath9k-devel] ath9k: injecting frames at a rate other than 1Mbps

[rootkit85 at yahoo.it]

On Tue, Mar 2, 2010 at 9:00 PM, Andrew Watts <systemstalker@gmail.com> wrote:
> Hi,
>
> I am trying to inject frames at a specific rate (54 Mbps, 36 Mbps etc) but
> everything seems to come out at 1Mbps.? I patched the driver with the code
> found in this thread here, but frames are still transmitted at 1Mbps over
> the air.? I have looked at the radiotap header for the frame I am injecting
> and everything seems fine to me.? I am seeing the same issue with the
> packetspammer app too.? Does anyone have a patch for this or know where I
> should be looking?? I have been playing with ath_buf_set rate in xmit.c and
> have not had any success.
>
> Ubuntu 9.10 - 2.6.31-19-generic-pae
> Compat-wireless driver from 11-30-2009 (should I upgrade to the latest?)
>
> Thanks in advance.
>
> Andrew
>
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>
>

Do you inject from userspace or kernelspace?
How do you know that they are sent at 1 Mbit? Do you sniff from another pc?
My patch was tested only with kernelspace injection, feedback is welcome.

-- 
Matteo Croce
OpenWrt developer
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[ath9k-devel] ath9k: injecting frames at a rate other than 1Mbps

[Pavel Roskin]

On Tue, 2010-03-02 at 22:25 +0100, rootkit85 at yahoo.it wrote:

> Do you inject from userspace or kernelspace?
> How do you know that they are sent at 1 Mbit? Do you sniff from another pc?
> My patch was tested only with kernelspace injection, feedback is welcome.

I think that part is wrong:

+					if (sband->bitrates[i].bitrate <=
+						*iterator.this_arg * 5) {
+						info->control.rates[0].idx = i;
+						break;
+					}

If a bitrate is less than the requested one, it would still match.

I think we should require an exact match.  Requests to use an
unsupported rate should result in dropping the packet.  That applies to
rate 0 as well, unless there is a special interpretation in the
standard.  I don't see any: http://www.radiotap.net/defined-fields/Rate

I tried the part of you patch that handles IEEE80211_RADIOTAP_RATE, but
it still would not work.  It turns out the rate control would override
the rate.  I don't see an easy way to prevent it short of introducing
another flag.

I've made an alternative patch and I'll submit it to linux-wireless
shortly.  It actually works for userspace injection.

-- 
Regards,
Pavel Roskin