Re: [PATCH v3 3/3] cfg80211: Allow usermode to query wiphy specific regd info

On Wed, Nov 26, 2014 at 6:47 PM, Luis R. Rodriguez [off-list ref] wrote:

On Wed, Nov 26, 2014 at 11:43 AM, Arik Nemtsov [off-list ref] wrote:

quoted

On Tue, Nov 25, 2014 at 10:28 PM, Luis R. Rodriguez [off-list ref] wrote:

quoted

On Sun, Nov 23, 2014 at 05:02:21PM +0200, Arik Nemtsov wrote:

quoted

From: Jonathan Doron <redacted>

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.

Signed-off-by: Jonathan Doron <redacted>
Signed-off-by: Arik Nemtsov <redacted>
---
 include/uapi/linux/nl80211.h | 18 ++++++++++-
 net/wireless/nl80211.c       | 71 ++++++++++++++++++++++++++++++++++++--------
 net/wireless/reg.c           |  2 +-
 net/wireless/reg.h           |  1 +
 4 files changed, 78 insertions(+), 14 deletions(-)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 3771e7d..b222e5c 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h

@@ -252,7 +252,12 @@
  *   %NL80211_ATTR_IFINDEX.
  *
  * @NL80211_CMD_GET_REG: ask the wireless core to send us its currently set
- *   regulatory domain.
+ *   regulatory domain. If %NL80211_ATTR_WIPHY is specified and the device
+ *   self-manages its regulatory settings, its private regulatory domain
+ *   will be returned.
+ *   If %NL80211_ATTR_WIPHY_GET_PRIV_REG is specified in addition to
+ *   %NL80211_ATTR_WIPHY, a device's private regulatory domain will be
+ *   returned, even if it's regulatory is not self-managed.
  * @NL80211_CMD_SET_REG: Set current regulatory domain. CRDA sends this command
  *   after being queried by the kernel. CRDA replies by sending a regulatory
  *   domain structure which consists of %NL80211_ATTR_REG_ALPHA set to our

@@ -1693,6 +1698,14 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_MAC_MASK: MAC address mask
  *
+ * @NL80211_ATTR_WIPHY_SELF_MANAGED_REG: flag attribute indicating the
+ *   regulatory information was obtained from the private regdomain
+ *   of a device with self-managed regulatory.
+ * @NL80211_ATTR_WIPHY_GET_PRIV_REG: flag attribute indicating the regulatory
+ *   information should be obtained from a device's private regdomain,
+ *   if it exists. This will happen even if the device is not self-managing
+ *   its regulatory.

As with REGULATORY_WIPHY_SELF_MANAGED we need a flag that cfg80211 sets for
drivers that use regulatory_hint() API, perhaps REGULATORY_WIPHY_REG_HINT.
Then this can be used by cfg80211 to send to userspace regdomains for wiphys
that have used this API. Below you enable userspace to only query for these
explictly but we want to be able to let userspace get all information, ie
through 'iw reg get'. This should go in as a separate patch along with
NL80211_ATTR_WIPHY_GET_PRIV_REG as its use predates
NL80211_ATTR_WIPHY_SELF_MANAGED_REG, this will also let you stuff in the boiler
plate code for getting that reg first, getting self managed regd's can then
go in as a clear secondary evolutionary step.

Note that we don't really need the new REGULATORY_WIPHY_REG_HINT.. If
a wiphy is not self-managed, we can just put
NL80211_ATTR_WIPHY_PRIV_REG, since it's obvious the regulatory_hint
API was used.

What if a driver sets the managed flag and then uses regulatory_hint()
? Either way if this is addressed and we can also infer what type of
wiphy->regd it is well that's OK with me, the flag idea was just in
case we needed it, so I think you might be right.

A self-managed device can't use regulatory_hint().. This is the
regular path which also updates the cfg80211 regdomain.
If a device tries to do that, the new regd from CRDA will never reach
it. So we're covered here.

Arik