RTL8187 in master mode with hostapd

RTL8187 in master mode with hostapd

[Marco]

Hi,

I own an Alfa AWUS036H network adapter using the rtl8187 driver on a
Debian box running kernel 3.5.0. I want to use it with hostapd, which
apparently requires master mode to be enabled in the driver.

The page http://linuxwireless.org/en/users/Drivers/rtl8187 states:

  not working yet: AP/Master mode

What means *yet*? Is it planned to add master mode support in the
near future? Do you have other suggestions what I could do to get
the driver to work together with hostap?

Disclaimer: I am not an expert in those things. I set up the access
point some years ago, then the network adapter started to function
unreliably. I then replaced it with a different one (the
abovementioned 036H) and didn't manage to get my setup running
again.


Best regards

Marco

Re: RTL8187 in master mode with hostapd

[Larry Finger]

On 07/27/2012 10:11 AM, Marco wrote:
> Hi,
>
> I own an Alfa AWUS036H network adapter using the rtl8187 driver on a
> Debian box running kernel 3.5.0. I want to use it with hostapd, which
> apparently requires master mode to be enabled in the driver.
>
> The page http://linuxwireless.org/en/users/Drivers/rtl8187 states:
>
>    not working yet: AP/Master mode
>
> What means *yet*? Is it planned to add master mode support in the
> near future? Do you have other suggestions what I could do to get
> the driver to work together with hostap?
>
> Disclaimer: I am not an expert in those things. I set up the access
> point some years ago, then the network adapter started to function
> unreliably. I then replaced it with a different one (the
> abovementioned 036H) and didn't manage to get my setup running
> again.

In the case of the RTL8187L, which is the chip in your Alfa device, it means 
*never*. That chip only has a single hardware transmit queue and the work of 
getting the high-priority traffic, such as beacons, transmitted at the correct 
time would be much more than it would be worth.

Sorry,

Larry

Re: RTL8187 in master mode with hostapd

[Marco]

On 2012-07-28 Larry Finger
<Larry.Finger@lwfinger.net> wrote:

Hi Larry,

> In the case of the RTL8187L, which is the chip in your Alfa device, it means 
> *never*.

Thanks for this straightforward answer. In this case it makes sense
to change the point AP/Master mode on the driver description page

http://linuxwireless.org/en/users/Drivers/rtl8187

from “not working yet” to “not supported”.

> That chip only has a single hardware transmit queue and the work of 
> getting the high-priority traffic, such as beacons, transmitted at the correct 
> time would be much more than it would be worth.

I wasn't aware of that when I bought the device.

It might be off-topic here, but what chip (or device) would you
recommend instead, for use in an AP? It has to be connected via USB,
support master mode and, only if possible, run without the need of
proprietary firmware.


Thanks for taking the time to deal with my issue.

Marco

Re: RTL8187 in master mode with hostapd

[Larry Finger]

On 07/28/2012 02:16 PM, Marco wrote:
> On 2012-07-28 Larry Finger
> <Larry.Finger@lwfinger.net> wrote:
>
> Hi Larry,
>
>> In the case of the RTL8187L, which is the chip in your Alfa device, it means
>> *never*.
>
> Thanks for this straightforward answer. In this case it makes sense
> to change the point AP/Master mode on the driver description page
>
> http://linuxwireless.org/en/users/Drivers/rtl8187
>
> from “not working yet” to “not supported”.
>
>> That chip only has a single hardware transmit queue and the work of
>> getting the high-priority traffic, such as beacons, transmitted at the correct
>> time would be much more than it would be worth.
>
> I wasn't aware of that when I bought the device.
>
> It might be off-topic here, but what chip (or device) would you
> recommend instead, for use in an AP? It has to be connected via USB,
> support master mode and, only if possible, run without the need of
> proprietary firmware.
>
>
> Thanks for taking the time to deal with my issue.

As far as I know, there are no USB devices that meet all of your requirements. 
If you relax the one about external firmware, then any of the USB devices that 
run rt2800usb (Ralink) should support master mode. I'm not at home now and do 
not have mine with me, thus I cannot give you a make/model. An older dual-band 
model is the Dell 1450U. These are available new on E-bay for $10. Perhaps 
someone else on this list can suggest other specific models. I am quite certain 
that Atheros also has such devices.

Larry

Re: RTL8187 in master mode with hostapd

[Joelle]

Larry Finger <Larry.Finger@...> writes:

> 
> As far as I know, there are no USB devices that meet all of your
requirements. 
> If you relax the one about external firmware, then any of the USB devices
that 
> run rt2800usb (Ralink) should support master mode. I'm not at home now and do 
> not have mine with me, thus I cannot give you a make/model. An older
dual-band 
> model is the Dell 1450U. These are available new on E-bay for $10. Perhaps 
> someone else on this list can suggest other specific models. I am quite
certain 
> that Atheros also has such devices.
> 
> Larry
> 
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The statement that the rtl8187 CANNOT be set as an AP is utterly wrong. Alfa
networks provides a Windows utility that allows one to setup an AP, I've
used it and it works(as well as anything on windows). It seems that this is
a crime against technology that windows can provide a functionality that
Linux cannot or may never. 

Re: RTL8187 in master mode with hostapd

[Larry Finger]

On 04/17/2013 07:51 AM, Joelle wrote:
>
> The statement that the rtl8187 CANNOT be set as an AP is utterly wrong. Alfa
> networks provides a Windows utility that allows one to setup an AP, I've
> used it and it works(as well as anything on windows). It seems that this is
> a crime against technology that windows can provide a functionality that
> Linux cannot or may never.

I did not say that the RTL8187{B,L} cannot be used as an AP! I said that rtl8187 
cannot. The capitalization is important. With caps, it refers to a device; 
without implies a driver.

I am not sure how well an RTL8187L would work as it only has a single transmit 
queue, but perhaps it would work.

If you think there is a "crime against technology", then you need to be the one 
to make the necessary changes to rtl8187. After all, the source is open.

Larry

Re: RTL8187 in master mode with hostapd

[Joelle]

> I did not say that the RTL8187{B,L} cannot be used as an AP! I said that
rtl8187 
> cannot. The capitalization is important. With caps, it refers to a device; 
> without implies a driver.
> 
> I am not sure how well an RTL8187L would work as it only has a single
transmit 
> queue, but perhaps it would work.
> 
> If you think there is a "crime against technology", then you need to be
the one 
> to make the necessary changes to rtl8187. After all, the source is open.
> 
> Larry
> 

The driver as distributed with the distros cannot provided AP functionality,
this is true. However one only needs to patch in the proper call functions
for AP functionality to work, which is what I did with the power functions.
The patch is available on the Realtek site but is formatted for kernal ver
2.something and thus most be painstakingly edited in. This means that the
driver as provided by the manufacturer, which was also provided as open
source, utilized these functions and more. But as this chipset is now
considered legacy by the manufacturer they no longer update the driver, thus
breaking compatibility with new generations of linux.

I see this as a "crime against technology", and the comment that
compatibility will 'never' come because the ability is and was available in
these prior versions, all be it patched. This means that very little work
needs to be done by someone who knows what they are doing. As for myself, I
only 'almost' know what I'm doing and can't provide the technical expertise
required to build a reliable enough driver to be given to the distros, nor
do I have the repute to suggest an integration.

It's also a crime that the windows drivers continue to be updated, at the
least a newish win 7 is available, but the linux community does not wish to
peruse greater functionality. While I can't substantiate this with any
degree of certainty I do recall an Ubuntu mod saying that they will never
provider greater support because the primary use for the Alfa adapters,
which was the primary purchaser of said chipsets, is for hacking purposes.
This is a tragedy as the rtl8187, or any in that series, as well as the Alfa
adapters can and do provide an excellent platform for many wifi needs.

I also should address the transmit issue as well if I'm to maintain any
credibility. High priority kernal patches can be used to provide one's
software router with appropriate timing. In fact there were, perhaps are, a
lot of 'very cheep' wifi router which had limited capabilities in their
chipsets but made up for those deficiencies with software 'cheats'. At this
moment I'm serving my 'very' small town with free wifi internet through a
Windows XP Aspire One, with routing provided by my dedicated linux soft
router. Despite the slowness of the laptop, idiocies of windows, and other
drawbacks with my setup I've had up to 30 people surfing at once with a peek
of 50 or so sitting authenticated.

It's a shame I can't integrate my soft-router and my soft-AP into one unit
without having to downgrade to an earlier release or having an aneurysm
because I'm staring at code during my few free time hours.

Re: RTL8187 in master mode with hostapd

[Larry Finger]

On 04/17/2013 10:42 AM, Joelle wrote:
>
> The driver as distributed with the distros cannot provided AP functionality,
> this is true. However one only needs to patch in the proper call functions
> for AP functionality to work, which is what I did with the power functions.
> The patch is available on the Realtek site but is formatted for kernal ver
> 2.something and thus most be painstakingly edited in. This means that the
> driver as provided by the manufacturer, which was also provided as open
> source, utilized these functions and more. But as this chipset is now
> considered legacy by the manufacturer they no longer update the driver, thus
> breaking compatibility with new generations of linux.

Again, you are mixing apples and oranges. The driver on the Realtek web site 
does not use mac80211; whereas the one in the kernel does.

> I see this as a "crime against technology", and the comment that
> compatibility will 'never' come because the ability is and was available in
> these prior versions, all be it patched. This means that very little work
> needs to be done by someone who knows what they are doing. As for myself, I
> only 'almost' know what I'm doing and can't provide the technical expertise
> required to build a reliable enough driver to be given to the distros, nor
> do I have the repute to suggest an integration.

If you do not have the skills to integrate the changes, then you need to find 
someone that can. I must say that accusing peoples of "crimes against 
technology" is hardly tghe way to start.

> It's also a crime that the windows drivers continue to be updated, at the
> least a newish win 7 is available, but the linux community does not wish to
> peruse greater functionality. While I can't substantiate this with any
> degree of certainty I do recall an Ubuntu mod saying that they will never
> provider greater support because the primary use for the Alfa adapters,
> which was the primary purchaser of said chipsets, is for hacking purposes.
> This is a tragedy as the rtl8187, or any in that series, as well as the Alfa
> adapters can and do provide an excellent platform for many wifi needs.

If the Ubuntu quote was referring to using the driver with air-crack, then I agree.

> I also should address the transmit issue as well if I'm to maintain any
> credibility. High priority kernal patches can be used to provide one's
> software router with appropriate timing. In fact there were, perhaps are, a
> lot of 'very cheep' wifi router which had limited capabilities in their
> chipsets but made up for those deficiencies with software 'cheats'. At this
> moment I'm serving my 'very' small town with free wifi internet through a
> Windows XP Aspire One, with routing provided by my dedicated linux soft
> router. Despite the slowness of the laptop, idiocies of windows, and other
> drawbacks with my setup I've had up to 30 people surfing at once with a peek
> of 50 or so sitting authenticated.

If you have the ability to setup and maintain something like that, then I would 
think you should be able to port the non-mac80211 driver to modern kernels, or 
modify the kernel driver. At the moment, I am working on 3 drivers for which 
there is *NO* Linux driver publicly available. To me, that has a much higher 
priority. Besides, I am not getting paid to do this, and you are making me want 
to go fishing.

Larry