Re: [PATCH v2 4/4] cfg80211: Allow usermode to query wiphy specific regd info

2014-11-21 Thread Arik Nemtsov
On Thu, Nov 20, 2014 at 10:54 PM, Luis R. Rodriguez mcg...@suse.com wrote:

 Then it gets the global one, and it knows it via a wiphy attribute:

   (wiphy-regulatory_flags  REGULATORY_WIPHY_SELF_MANAGED) 
 +   (nla_put_flag(msg, NL80211_ATTR_WIPHY_SELF_MANAGED_REG)))
 +   goto nla_put_failure;

 (we won't do this put_flag if it's global)

 You can still follow this on wpa_s for REGULATORY_WIPHY_SELF_MANAGED, and
 the other type that uses wiphy-regd would still follow the global regdomain.
 The other flag I'm looking for is more informational for userspace in 
 particular
 'iw reg get' (for central and all devices) or 'iw reg get dev wlan0'.

I'm not sure why another flag is needed for userspace. If we have
SELF_MANAGED, we'll return the per-wiphy one (if a wiphy_idx is given
to us of course). For validation purposes, the global one is used in
other cases. And for CUSTOM_REG, we'll return the global one (we don't
have the per-wiphy information in cfg80211).

Arik
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Re: [PATCH v2 4/4] cfg80211: Allow usermode to query wiphy specific regd info

2014-11-20 Thread Johannes Berg
On Sun, 2014-11-16 at 13:06 +0200, Arik Nemtsov wrote:

 We intend to add a patch to wpa_s to always add the wiphy_idx to
 NL80211_CMD_GET_REG. With the current approach only drivers with
 SELF_MANAGED_REG will get wiphy-regd back. This is ok since these are
 new drivers, which are familiar with this API.
 
 But if we use your suggestion and always return wiphy-regd, then some
 driver like ath9k that uses regulatory_hint() will now get it's
 private regd returned to the wpa_s that manages it. I'm not saying
 it's necessarily bad, but it's different than what was returned
 before. The cfg80211 regdomain is intersected with wiphy-regd, so now
 ath9k will start getting more permissive channels in usermode.
 
 So we thought it's best to enable the new behavior only if the driver
 explicitly wants it, using a new regulatory flag.

How does this work the other way around - i.e. a newer wpa_s requesting
per-wiphy information but it not being present?

It seems to me that either way what the kernel should return is the
information that will actually be applied when validated, which is of
course not possible when there are wiphy-specific regdomains and a
global one is requested (unless there's just one wiphy, which might be
something to consider making work?)

I also don't actually see a driver regulatory flag in this patch, as
expected, so not sure what exactly you're talking about above?

johannes

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Re: [PATCH v2 4/4] cfg80211: Allow usermode to query wiphy specific regd info

2014-11-20 Thread Luis R. Rodriguez
On Thu, Nov 20, 2014 at 06:47:24PM +0200, Arik Nemtsov wrote:
 On Thu, Nov 20, 2014 at 5:22 PM, Johannes Berg
 johan...@sipsolutions.net wrote:
  On Sun, 2014-11-16 at 13:06 +0200, Arik Nemtsov wrote:
 
  We intend to add a patch to wpa_s to always add the wiphy_idx to
  NL80211_CMD_GET_REG. With the current approach only drivers with
  SELF_MANAGED_REG will get wiphy-regd back. This is ok since these are
  new drivers, which are familiar with this API.
 
  But if we use your suggestion and always return wiphy-regd, then some
  driver like ath9k that uses regulatory_hint() will now get it's
  private regd returned to the wpa_s that manages it. I'm not saying
  it's necessarily bad, but it's different than what was returned
  before. The cfg80211 regdomain is intersected with wiphy-regd, so now
  ath9k will start getting more permissive channels in usermode.
 
  So we thought it's best to enable the new behavior only if the driver
  explicitly wants it, using a new regulatory flag.
 
  How does this work the other way around - i.e. a newer wpa_s requesting
  per-wiphy information but it not being present?
 
 Then it gets the global one, and it knows it via a wiphy attribute:
 
   (wiphy-regulatory_flags  REGULATORY_WIPHY_SELF_MANAGED) 
 +   (nla_put_flag(msg, NL80211_ATTR_WIPHY_SELF_MANAGED_REG)))
 +   goto nla_put_failure;
 
 (we won't do this put_flag if it's global)

You can still follow this on wpa_s for REGULATORY_WIPHY_SELF_MANAGED, and
the other type that uses wiphy-regd would still follow the global regdomain.
The other flag I'm looking for is more informational for userspace in particular
'iw reg get' (for central and all devices) or 'iw reg get dev wlan0'.

 The supplicant patches are not up yet, but I think for now we will
 just act according to the global one. Anyway it has the option to
 change policy, since it knows.
 
 
  It seems to me that either way what the kernel should return is the
  information that will actually be applied when validated, which is of
  course not possible when there are wiphy-specific regdomains and a
  global one is requested (unless there's just one wiphy, which might be
  something to consider making work?)
 
 Well the cfg80211 regdomain is always intersected with all wiphy-regd
 in the system, so the global one is always less permissive.
 This is of course true before REGULATORY_WIPHY_SELF_MANAGED - in this
 case wiphy-regd will not affect the global regd.

The discrepancy is a long term issue when device combing but it seems folks
dealing with REGULATORY_WIPHY_SELF_MANAGED are OK with supporting whatever
issues come up.

 With CUSTOM_REG we have a special case, since the regulatory code
 doesn't set wiphy-regd, it just applies a user supplied regd to the
 wiphy channels (which get validated).

Its a custom world regdom, its a minimum base set. New information is
always welcomed to help it comply further, and that's what happens.

 If the user also happens to set  wiphy-regd himself with CUSTOM_REG,
 then it makes sense to return the per-wiphy one. The global regd is
 meaningless anyway for CUSTOM_REG, and the per-wiphy one might be too.
 But I guess we can return it if it's there?

When CUSTOM_REG is used we already have code that deals with what is
allowed or now given new hints from different sources, wpa_s can
and should rely on the channel information state it is in already.
All the intersection logic is already dealt for the device. The only
thing wpa_s could probably care more about from the regulatory data is
the actual ISO3166 alpha2 used for country IEs.

  Luis
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Re: [PATCH v2 4/4] cfg80211: Allow usermode to query wiphy specific regd info

2014-11-16 Thread Arik Nemtsov
On Fri, Nov 14, 2014 at 1:13 AM, Luis R. Rodriguez mcg...@suse.com wrote:
 On Thu, Nov 13, 2014 at 06:13:39PM +0200, Arik Nemtsov wrote:
 From: Jonathan Doron j...@wizery.com

 Allow usermode to query wiphy-specific regd info, for drivers that use
 wiphy-specific regulatory management.

 Use the existing API for sending regdomain info to usermode, but return
 the wiphy-specific regd in case wiphy index is provided and the driver
 employs wiphy-specific management. This implies user and kernel-mode
 support for the feature and is backward compatible.

 This patch does not address my feedback about making this generic
 to any wiphy-regd.

Copy-pasting my previous reply:

Well always sending wiphy-regd whenever it is set is easy, but it
might be problematic I guess:

We intend to add a patch to wpa_s to always add the wiphy_idx to
NL80211_CMD_GET_REG. With the current approach only drivers with
SELF_MANAGED_REG will get wiphy-regd back. This is ok since these are
new drivers, which are familiar with this API.

But if we use your suggestion and always return wiphy-regd, then some
driver like ath9k that uses regulatory_hint() will now get it's
private regd returned to the wpa_s that manages it. I'm not saying
it's necessarily bad, but it's different than what was returned
before. The cfg80211 regdomain is intersected with wiphy-regd, so now
ath9k will start getting more permissive channels in usermode.

So we thought it's best to enable the new behavior only if the driver
explicitly wants it, using a new regulatory flag.

Arik
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Re: [PATCH v2 4/4] cfg80211: Allow usermode to query wiphy specific regd info

2014-11-13 Thread Luis R. Rodriguez
On Thu, Nov 13, 2014 at 06:13:39PM +0200, Arik Nemtsov wrote:
 From: Jonathan Doron j...@wizery.com
 
 Allow usermode to query wiphy-specific regd info, for drivers that use
 wiphy-specific regulatory management.
 
 Use the existing API for sending regdomain info to usermode, but return
 the wiphy-specific regd in case wiphy index is provided and the driver
 employs wiphy-specific management. This implies user and kernel-mode
 support for the feature and is backward compatible.

This patch does not address my feedback about making this generic
to any wiphy-regd.

  Luis
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