Re: [RFC 1/3] cfg80211: Make pre-CAC results valid only for ETSI domain

2017-01-31 Thread Thiagarajan, Vasanthakumar 
On Thursday 26 January 2017 03:04 PM, Johannes Berg wrote:
>
>> +/* Should we apply the grace period during beaconing
>> interface
>> + * shutdown also?
>> + */
>> +cfg80211_sched_dfs_chan_update(rdev);
>
> It might make some sense, say if hostapd crashes and you restart it
> automatically or something?

Sure. Initially it looked tricky to handle this. But I guess we can store
the DFS channel and the time stamp (rdev specific) when the beaconing interface
is brought down. cfg80211_dfs_channels_update_work() can use these information
and apply the grace period before setting the DFS channel state back to 
'usable'.

>
>>  return err;
>> diff --git a/net/wireless/chan.c b/net/wireless/chan.c
>> index 5497d022..090309a 100644
>> --- a/net/wireless/chan.c
>> +++ b/net/wireless/chan.c
>> @@ -456,6 +456,102 @@ bool cfg80211_chandef_dfs_usable(struct wiphy
>> *wiphy,
>>  return (r1 + r2 > 0);
>>   }
>>
>> +static bool cfg80211_5ghz_sub_chan(struct cfg80211_chan_def
>> *chandef,
>> +   struct ieee80211_channel *chan)
>
> This could use some explanation, and I don't see anything that's really
> 5 GHz specific in here, so why that in the function name?

Sure.

>
>> +u32 start_freq_seg0 = 0, end_freq_seg0 = 0;
>> +u32 start_freq_seg1 = 0, end_freq_seg1 = 0;
>> +
>> +if (chandef->chan->center_freq == chan->center_freq)
>> +return true;
>> +
>> +switch (chandef->width) {
>> +case NL80211_CHAN_WIDTH_40:
>> +start_freq_seg0 = chandef->center_freq1 - 20;
>> +end_freq_seg0 = chandef->center_freq1 + 20;
>> +break;
>> +case NL80211_CHAN_WIDTH_80P80:
>> +start_freq_seg1 = chandef->center_freq2 - 40;
>> +end_freq_seg1 = chandef->center_freq2 + 40;
>> +/* fall through */
>> +case NL80211_CHAN_WIDTH_80:
>> +start_freq_seg0 = chandef->center_freq1 - 40;
>> +end_freq_seg0 = chandef->center_freq1 + 40;
>> +break;
>> +case NL80211_CHAN_WIDTH_160:
>> +start_freq_seg0 = chandef->center_freq1 - 80;
>> +end_freq_seg0 = chandef->center_freq1 + 80;
>> +break;
>> +case NL80211_CHAN_WIDTH_20_NOHT:
>> +case NL80211_CHAN_WIDTH_20:
>> +case NL80211_CHAN_WIDTH_5:
>> +case NL80211_CHAN_WIDTH_10:
>> +break;
>> +}
>> +
>> +if (chan->center_freq > start_freq_seg0 &&
>> +chan->center_freq < end_freq_seg0)
>> +return true;
>> +
>> +return chan->center_freq > start_freq_seg1 &&
>> +chan->center_freq < end_freq_seg1;
>> +}
>
> It's also written pretty oddly... The 5/10/20 cases could return
> immediately, the start/end could be replaced by width, and the
> initializations wouldn't be needed at all ... I think we can do better
> here.

Sure, I'll improve this function.

>
>> +bool cfg80211_5ghz_any_wiphy_oper_chan(struct wiphy *wiphy,
>> +   struct ieee80211_channel
>> *chan)
>
> Again, nothing 5 GHz specific.

Ok.

>
>> +struct wireless_dev *wdev;
>> +
>> +ASSERT_RTNL();
>> +
>> +if (!(chan->flags & IEEE80211_CHAN_RADAR))
>> +return false;
>> +
>> +list_for_each_entry(wdev, >wdev_list, list) {
>> +if (!cfg80211_beaconing_iface_active(wdev))
>> +continue;
>> +
>> +if (cfg80211_5ghz_sub_chan(>chandef, chan))
>> +return true;
>> +}
>> +
>> +return false;
>> +}
>>
>>   static bool cfg80211_get_chans_dfs_available(struct wiphy *wiphy,
>>   u32 center_freq,
>> diff --git a/net/wireless/core.h b/net/wireless/core.h
>> index 58ca206..327fe95 100644
>> --- a/net/wireless/core.h
>> +++ b/net/wireless/core.h
>> @@ -459,6 +459,13 @@ void cfg80211_set_dfs_state(struct wiphy *wiphy,
>>   cfg80211_chandef_dfs_cac_time(struct wiphy *wiphy,
>>const struct cfg80211_chan_def
>> *chandef);
>>
>> +void cfg80211_sched_dfs_chan_update(struct
>> cfg80211_registered_device *rdev);
>> +
>> +bool cfg80211_5ghz_any_wiphy_oper_chan(struct wiphy *wiphy,
>> +   struct ieee80211_channel
>> *chan);
>> +
>> +bool cfg80211_beaconing_iface_active(struct wireless_dev *wdev);
>> +
>>   static inline unsigned int elapsed_jiffies_msecs(unsigned long
>> start)
>>   {
>>  unsigned long end = jiffies;
>> diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
>> index 364f900..10bf040 100644
>> --- a/net/wireless/ibss.c
>> +++ b/net/wireless/ibss.c
>> @@ -190,6 +190,7 @@ static void __cfg80211_clear_ibss(struct
>> net_device *dev, bool nowext)
>>  if (!nowext)
>>  wdev->wext.ibss.ssid_len = 0;
>>   #endif
>> +cfg80211_sched_dfs_chan_update(rdev);
>>   }
>>
>>   void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
>> diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
>> index 2d8518a..ec0b1c2

Re: [RFC 1/3] cfg80211: Make pre-CAC results valid only for ETSI domain

2017-01-26 Thread Johannes Berg 

> + /* Should we apply the grace period during beaconing
> interface
> +  * shutdown also?
> +  */
> + cfg80211_sched_dfs_chan_update(rdev);

It might make some sense, say if hostapd crashes and you restart it
automatically or something?

>   return err;
> diff --git a/net/wireless/chan.c b/net/wireless/chan.c
> index 5497d022..090309a 100644
> --- a/net/wireless/chan.c
> +++ b/net/wireless/chan.c
> @@ -456,6 +456,102 @@ bool cfg80211_chandef_dfs_usable(struct wiphy
> *wiphy,
>   return (r1 + r2 > 0);
>  }
>  
> +static bool cfg80211_5ghz_sub_chan(struct cfg80211_chan_def
> *chandef,
> +    struct ieee80211_channel *chan)

This could use some explanation, and I don't see anything that's really
5 GHz specific in here, so why that in the function name?

> + u32 start_freq_seg0 = 0, end_freq_seg0 = 0;
> + u32 start_freq_seg1 = 0, end_freq_seg1 = 0;
> +
> + if (chandef->chan->center_freq == chan->center_freq)
> + return true;
> +
> + switch (chandef->width) {
> + case NL80211_CHAN_WIDTH_40:
> + start_freq_seg0 = chandef->center_freq1 - 20;
> + end_freq_seg0 = chandef->center_freq1 + 20;
> + break;
> + case NL80211_CHAN_WIDTH_80P80:
> + start_freq_seg1 = chandef->center_freq2 - 40;
> + end_freq_seg1 = chandef->center_freq2 + 40;
> + /* fall through */
> + case NL80211_CHAN_WIDTH_80:
> + start_freq_seg0 = chandef->center_freq1 - 40;
> + end_freq_seg0 = chandef->center_freq1 + 40;
> + break;
> + case NL80211_CHAN_WIDTH_160:
> + start_freq_seg0 = chandef->center_freq1 - 80;
> + end_freq_seg0 = chandef->center_freq1 + 80;
> + break;
> + case NL80211_CHAN_WIDTH_20_NOHT:
> + case NL80211_CHAN_WIDTH_20:
> + case NL80211_CHAN_WIDTH_5:
> + case NL80211_CHAN_WIDTH_10:
> + break;
> + }
> +
> + if (chan->center_freq > start_freq_seg0 &&
> + chan->center_freq < end_freq_seg0)
> + return true;
> +
> + return chan->center_freq > start_freq_seg1 &&
> + chan->center_freq < end_freq_seg1;
> +}

It's also written pretty oddly... The 5/10/20 cases could return
immediately, the start/end could be replaced by width, and the
initializations wouldn't be needed at all ... I think we can do better
here.

> +bool cfg80211_5ghz_any_wiphy_oper_chan(struct wiphy *wiphy,
> +    struct ieee80211_channel
> *chan)

Again, nothing 5 GHz specific.

> + struct wireless_dev *wdev;
> +
> + ASSERT_RTNL();
> +
> + if (!(chan->flags & IEEE80211_CHAN_RADAR))
> + return false;
> +
> + list_for_each_entry(wdev, >wdev_list, list) {
> + if (!cfg80211_beaconing_iface_active(wdev))
> + continue;
> +
> + if (cfg80211_5ghz_sub_chan(>chandef, chan))
> + return true;
> + }
> +
> + return false;
> +}
>  
>  static bool cfg80211_get_chans_dfs_available(struct wiphy *wiphy,
>    u32 center_freq,
> diff --git a/net/wireless/core.h b/net/wireless/core.h
> index 58ca206..327fe95 100644
> --- a/net/wireless/core.h
> +++ b/net/wireless/core.h
> @@ -459,6 +459,13 @@ void cfg80211_set_dfs_state(struct wiphy *wiphy,
>  cfg80211_chandef_dfs_cac_time(struct wiphy *wiphy,
>     const struct cfg80211_chan_def
> *chandef);
>  
> +void cfg80211_sched_dfs_chan_update(struct
> cfg80211_registered_device *rdev);
> +
> +bool cfg80211_5ghz_any_wiphy_oper_chan(struct wiphy *wiphy,
> +    struct ieee80211_channel
> *chan);
> +
> +bool cfg80211_beaconing_iface_active(struct wireless_dev *wdev);
> +
>  static inline unsigned int elapsed_jiffies_msecs(unsigned long
> start)
>  {
>   unsigned long end = jiffies;
> diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
> index 364f900..10bf040 100644
> --- a/net/wireless/ibss.c
> +++ b/net/wireless/ibss.c
> @@ -190,6 +190,7 @@ static void __cfg80211_clear_ibss(struct
> net_device *dev, bool nowext)
>   if (!nowext)
>   wdev->wext.ibss.ssid_len = 0;
>  #endif
> + cfg80211_sched_dfs_chan_update(rdev);
>  }
>  
>  void cfg80211_clear_ibss(struct net_device *dev, bool nowext)
> diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
> index 2d8518a..ec0b1c2 100644
> --- a/net/wireless/mesh.c
> +++ b/net/wireless/mesh.c
> @@ -262,6 +262,7 @@ int __cfg80211_leave_mesh(struct
> cfg80211_registered_device *rdev,
>   wdev->beacon_interval = 0;
>   memset(>chandef, 0, sizeof(wdev->chandef));
>   rdev_set_qos_map(rdev, dev, NULL);
> + cfg80211_sched_dfs_chan_update(rdev);
>   }
>  
>   return err;
> diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
> index 22b3d99..3c7e155 100644
> --- a/net/wireless/mlme.c

[RFC 1/3] cfg80211: Make pre-CAC results valid only for ETSI domain

2017-01-25 Thread Vasanthakumar Thiagarajan 
DFS requirement for ETSI domain (section 4.7.1.4 in
ETSI EN 301 893 V1.8.1) is the only one which explicitly
states that once DFS channel is marked as available afer
the CAC, this channel will remain in available state even
moving to a different operating channel. But the same is
not explicitly stated in FCC DFS requirement. Also, Pre-CAC
requriements are not explicitly mentioned in FCC requirement.
Current implementation in keeping DFS channel in available
state is same as described in ETSI domain.

For ETSI DFS domain, this patch gives a grace period of 2 seconds
since the completion of successful CAC before moving the channel's
DFS state to 'usable' from 'available' state. The same grace period
is checked against the channel's dfs_state_entered timestamp while
deciding if a DFS channel is available for operation. There is a new
radar event, NL80211_RADAR_PRE_CAC_EXPIRED, reported when DFS channel
is moved from available to usable state after the grace period. Also
make sure the DFS channel state is reset to usable once the beaconing
operation on that channel is brought down (like stop_ap, leave_ibss
and leave_mesh) in non-ETSI domain.

Signed-off-by: Vasanthakumar Thiagarajan 
---
 include/uapi/linux/nl80211.h |  5 +++
 net/wireless/ap.c|  5 +++
 net/wireless/chan.c  | 96 
 net/wireless/core.h  |  7 
 net/wireless/ibss.c  |  1 +
 net/wireless/mesh.c  |  1 +
 net/wireless/mlme.c  | 41 ++-
 net/wireless/reg.c   | 47 ++
 net/wireless/reg.h   | 14 +++
 9 files changed, 208 insertions(+), 9 deletions(-)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index d6c62ee..9d2d2b1 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -4893,12 +4893,17 @@ enum nl80211_smps_mode {
  * change to the channel status.
  * @NL80211_RADAR_NOP_FINISHED: The Non-Occupancy Period for this channel is
  * over, channel becomes usable.
+ * @NL80211_RADAR_PRE_CAC_EXPIRED: Channel Availability Check done on this
+ * non-operating channel is expired and no longer valid. New CAC must
+ * be done on this channel before starting the operation. This is not
+ * applicable for ETSI dfs domain where pre-CAC is valid for ever.
  */
 enum nl80211_radar_event {
NL80211_RADAR_DETECTED,
NL80211_RADAR_CAC_FINISHED,
NL80211_RADAR_CAC_ABORTED,
NL80211_RADAR_NOP_FINISHED,
+   NL80211_RADAR_PRE_CAC_EXPIRED,
 };
 
 /**
diff --git a/net/wireless/ap.c b/net/wireless/ap.c
index bdad1f9..25666d3 100644
--- a/net/wireless/ap.c
+++ b/net/wireless/ap.c
@@ -32,6 +32,11 @@ int __cfg80211_stop_ap(struct cfg80211_registered_device 
*rdev,
rdev_set_qos_map(rdev, dev, NULL);
if (notify)
nl80211_send_ap_stopped(wdev);
+
+   /* Should we apply the grace period during beaconing interface
+* shutdown also?
+*/
+   cfg80211_sched_dfs_chan_update(rdev);
}
 
return err;
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 5497d022..090309a 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -456,6 +456,102 @@ bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
return (r1 + r2 > 0);
 }
 
+static bool cfg80211_5ghz_sub_chan(struct cfg80211_chan_def *chandef,
+  struct ieee80211_channel *chan)
+{
+   u32 start_freq_seg0 = 0, end_freq_seg0 = 0;
+   u32 start_freq_seg1 = 0, end_freq_seg1 = 0;
+
+   if (chandef->chan->center_freq == chan->center_freq)
+   return true;
+
+   switch (chandef->width) {
+   case NL80211_CHAN_WIDTH_40:
+   start_freq_seg0 = chandef->center_freq1 - 20;
+   end_freq_seg0 = chandef->center_freq1 + 20;
+   break;
+   case NL80211_CHAN_WIDTH_80P80:
+   start_freq_seg1 = chandef->center_freq2 - 40;
+   end_freq_seg1 = chandef->center_freq2 + 40;
+   /* fall through */
+   case NL80211_CHAN_WIDTH_80:
+   start_freq_seg0 = chandef->center_freq1 - 40;
+   end_freq_seg0 = chandef->center_freq1 + 40;
+   break;
+   case NL80211_CHAN_WIDTH_160:
+   start_freq_seg0 = chandef->center_freq1 - 80;
+   end_freq_seg0 = chandef->center_freq1 + 80;
+   break;
+   case NL80211_CHAN_WIDTH_20_NOHT:
+   case NL80211_CHAN_WIDTH_20:
+   case NL80211_CHAN_WIDTH_5:
+   case NL80211_CHAN_WIDTH_10:
+   break;
+   }
+
+   if (chan->center_freq > start_freq_seg0 &&
+   chan->center_freq < end_freq_seg0)
+   return true;
+
+   return chan->center_freq > start_freq_seg1 &&
+   chan->center_freq < end_freq_seg1;
+}
+
+bool