[PATCH 0/2] modify the inclusion of supported channels IE

[PATCH 0/2] modify the inclusion of supported channels IE

[Ilan Peer]

The 80211-2012 specification defines in 8.4.2.20 that the supported
channels information element should contain a list of the channel subbands
in which the station is capable to operate. Change the mac80211 implementation
to add all the channels currently enabled by the device (excluding disabled
channels).

Note: the implementation is not complete as it missing an better handling
for subband in bands other than 2.4 GHz.

Ilan Peer (2):
  cfg80211: Add a function to get the number of enabled channels
  mac80211: Add all enabled channels to the supported channels element

 include/net/cfg80211.h |    9 ++++++
 net/mac80211/mlme.c    |   80 ++++++++++++++++++++++++++++++++++++++++++------
 net/wireless/util.c    |   21 +++++++++++++
 3 files changed, 100 insertions(+), 10 deletions(-)

-- 
1.7.10.4

[PATCH 1/2] cfg80211: Add a function to get the number of enabled channels

[Ilan Peer]

Add a utility function to get the number of channels enabled by
the device.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
---
 include/net/cfg80211.h |    9 +++++++++
 net/wireless/util.c    |   21 +++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 80a1021..405ef5b 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4532,6 +4532,15 @@ void cfg80211_report_wowlan_wakeup(struct wireless_dev *wdev,
  */
 void cfg80211_crit_proto_stopped(struct wireless_dev *wdev, gfp_t gfp);
 
+/**
+ * ieee80211_get_num_enabled_channels - get the number of channels supported
+ * and enabled by the device.
+ * @wiphy: the wiphy
+ *
+ * Return: the number of channels supported and enabled by the device.
+ */
+unsigned int ieee80211_get_num_enabled_channels(struct wiphy *wiphy);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 935dea9..fb5f685 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1462,6 +1462,27 @@ int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 	return 0;
 }
 
+unsigned int ieee80211_get_num_enabled_channels(struct wiphy *wiphy)
+{
+	struct ieee80211_supported_band *sband;
+	unsigned int n_channels, i, j;
+
+	for (i = 0, n_channels = 0; i < IEEE80211_NUM_BANDS; i++) {
+		sband = wiphy->bands[i];
+		if (!sband)
+			continue;
+
+		for (j = 0; j < sband->n_channels; j++) {
+			if (!(sband->channels[j].flags &
+			      IEEE80211_CHAN_DISABLED))
+				n_channels++;
+		}
+	}
+
+	return n_channels;
+}
+EXPORT_SYMBOL(ieee80211_get_num_enabled_channels);
+
 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
 const unsigned char rfc1042_header[] __aligned(2) =
-- 
1.7.10.4

[PATCH 1/2 v2] cfg80211: Add a function to get the number of supported channels

[Ilan Peer]

Add a utility function to get the number of channels supported by
the device, and update the places in the code that need this data.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
---
 include/net/cfg80211.h |    9 +++++++++
 net/wireless/nl80211.c |   13 ++-----------
 net/wireless/scan.c    |    7 ++-----
 net/wireless/sme.c     |   13 +++----------
 net/wireless/util.c    |   13 +++++++++++++
 5 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 56c5977..b5ed170 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4640,6 +4640,15 @@ void cfg80211_report_wowlan_wakeup(struct wireless_dev *wdev,
  */
 void cfg80211_crit_proto_stopped(struct wireless_dev *wdev, gfp_t gfp);
 
+/**
+ * ieee80211_get_num_supported_channels - get the number of channels supported
+ * by the device.
+ * @wiphy: the wiphy
+ *
+ * Return: the number of channels supported by the device.
+ */
+unsigned int ieee80211_get_num_supported_channels(struct wiphy *wiphy);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b4f40fe..2404564 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5285,12 +5285,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 			goto unlock;
 		}
 	} else {
-		enum ieee80211_band band;
-		n_channels = 0;
-
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
+		n_channels = ieee80211_get_num_supported_channels(wiphy);
 	}
 
 	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
@@ -5498,11 +5493,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 		if (!n_channels)
 			return -EINVAL;
 	} else {
-		n_channels = 0;
-
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
+		n_channels = ieee80211_get_num_supported_channels(wiphy);
 	}
 
 	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index a32d52a..2bf4686 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1089,11 +1089,8 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 	/* Determine number of channels, needed to allocate creq */
 	if (wreq && wreq->num_channels)
 		n_channels = wreq->num_channels;
-	else {
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
-	}
+	else
+		n_channles = ieee80211_get_num_supported_channels(wiphy);
 
 	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
 		       n_channels * sizeof(void *),
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 5d6e7bb..a635091 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -70,18 +70,11 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev)
 	if (rdev->scan_req)
 		return -EBUSY;
 
-	if (wdev->conn->params.channel) {
+	if (wdev->conn->params.channel)
 		n_channels = 1;
-	} else {
-		enum ieee80211_band band;
-		n_channels = 0;
+	else
+		n_channels = ieee80211_get_num_supported_channels(wdev->wiphy);
 
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
-			if (!wdev->wiphy->bands[band])
-				continue;
-			n_channels += wdev->wiphy->bands[band]->n_channels;
-		}
-	}
 	request = kzalloc(sizeof(*request) + sizeof(request->ssids[0]) +
 			  sizeof(request->channels[0]) * n_channels,
 			  GFP_KERNEL);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 5618888..959c43c 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1479,6 +1479,19 @@ int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 	return 0;
 }
 
+unsigned int ieee80211_get_num_supported_channels(struct wiphy *wiphy)
+{
+	enum ieee80211_band band;
+	unsigned int n_channels;
+
+	for (band = 0, n_channels = 0; band < IEEE80211_NUM_BANDS; band++)
+		if (wiphy->bands[band])
+			n_channels += wiphy->bands[band]->n_channels;
+
+	return n_channels;
+}
+EXPORT_SYMBOL(ieee80211_get_num_supported_channels);
+
 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
 const unsigned char rfc1042_header[] __aligned(2) =
-- 
1.7.10.4

Re: [PATCH 1/2 v2] cfg80211: Add a function to get the number of supported channels

[Johannes Berg]

On Thu, 2014-01-09 at 11:17 +0200, Ilan Peer wrote:


> +	else
> +		n_channles = ieee80211_get_num_supported_channels(wiphy);

err ...

johannes

Re: [PATCH 1/2 v2] cfg80211: Add a function to get the number of supported channels

[Johannes Berg]

On Thu, 2014-01-09 at 11:17 +0200, Ilan Peer wrote:

> +unsigned int ieee80211_get_num_supported_channels(struct wiphy *wiphy)
> +{
> +	enum ieee80211_band band;
> +	unsigned int n_channels;

Seems nicer to do the = 0 here rather than in the loop?

> +	for (band = 0, n_channels = 0; band < IEEE80211_NUM_BANDS; band++)

johannes

[PATCH 1/2 v3] cfg80211: Add a function to get the number of supported channels

[Ilan Peer]

Add a utility function to get the number of channels supported by
the device, and update the places in the code that need this data.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
---
 include/net/cfg80211.h |    9 +++++++++
 net/wireless/nl80211.c |   13 ++-----------
 net/wireless/scan.c    |    7 ++-----
 net/wireless/sme.c     |   13 +++----------
 net/wireless/util.c    |   13 +++++++++++++
 5 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 56c5977..b5ed170 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4640,6 +4640,15 @@ void cfg80211_report_wowlan_wakeup(struct wireless_dev *wdev,
  */
 void cfg80211_crit_proto_stopped(struct wireless_dev *wdev, gfp_t gfp);
 
+/**
+ * ieee80211_get_num_supported_channels - get the number of channels supported
+ * by the device.
+ * @wiphy: the wiphy
+ *
+ * Return: the number of channels supported by the device.
+ */
+unsigned int ieee80211_get_num_supported_channels(struct wiphy *wiphy);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b4f40fe..2404564 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5285,12 +5285,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 			goto unlock;
 		}
 	} else {
-		enum ieee80211_band band;
-		n_channels = 0;
-
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
+		n_channels = ieee80211_get_num_supported_channels(wiphy);
 	}
 
 	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
@@ -5498,11 +5493,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 		if (!n_channels)
 			return -EINVAL;
 	} else {
-		n_channels = 0;
-
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
+		n_channels = ieee80211_get_num_supported_channels(wiphy);
 	}
 
 	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index a32d52a..2bf4686 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1089,11 +1089,8 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 	/* Determine number of channels, needed to allocate creq */
 	if (wreq && wreq->num_channels)
 		n_channels = wreq->num_channels;
-	else {
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
-			if (wiphy->bands[band])
-				n_channels += wiphy->bands[band]->n_channels;
-	}
+	else
+		n_channles = ieee80211_get_num_supported_channels(wiphy);
 
 	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
 		       n_channels * sizeof(void *),
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 5d6e7bb..a635091 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -70,18 +70,11 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev)
 	if (rdev->scan_req)
 		return -EBUSY;
 
-	if (wdev->conn->params.channel) {
+	if (wdev->conn->params.channel)
 		n_channels = 1;
-	} else {
-		enum ieee80211_band band;
-		n_channels = 0;
+	else
+		n_channels = ieee80211_get_num_supported_channels(wdev->wiphy);
 
-		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
-			if (!wdev->wiphy->bands[band])
-				continue;
-			n_channels += wdev->wiphy->bands[band]->n_channels;
-		}
-	}
 	request = kzalloc(sizeof(*request) + sizeof(request->ssids[0]) +
 			  sizeof(request->channels[0]) * n_channels,
 			  GFP_KERNEL);
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 5618888..959c43c 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1479,6 +1479,19 @@ int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 	return 0;
 }
 
+unsigned int ieee80211_get_num_supported_channels(struct wiphy *wiphy)
+{
+	enum ieee80211_band band;
+	unsigned int n_channels;
+
+	for (band = 0, n_channels = 0; band < IEEE80211_NUM_BANDS; band++)
+		if (wiphy->bands[band])
+			n_channels += wiphy->bands[band]->n_channels;
+
+	return n_channels;
+}
+EXPORT_SYMBOL(ieee80211_get_num_supported_channels);
+
 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
 const unsigned char rfc1042_header[] __aligned(2) =
-- 
1.7.10.4

Re: [PATCH 1/2 v3] cfg80211: Add a function to get the number of supported channels

[Johannes Berg]

On Thu, 2014-01-09 at 11:37 +0200, Ilan Peer wrote:
> Add a utility function to get the number of channels supported by
> the device, and update the places in the code that need this data.

Applied with some fixes.

johannes

[PATCH 2/2] [RFC] mac80211: Add all enabled channels to the supported channels element

[Ilan Peer]

In the current implementation, in case that the AP supports
spectrum management, the supported channels information element added
to the association and re-association frames includes only the channels
that where in the same band as that of the operating channel of the AP.
However, the 80211-2012 specification defines in 8.4.2.20 that the supported
channels information element should contain a list of the channel subbands
in which the station is capable to operate.

Fix this gap by including all the channels enabled by the device
(excluding channels that are marked as disabled).

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
---
 net/mac80211/mlme.c |   80 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 70 insertions(+), 10 deletions(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 9c2c7ee..04da17d 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -540,6 +540,70 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
 	ieee80211_ie_build_vht_cap(pos, &vht_cap, cap);
 }
 
+static void ieee80211_add_supported_channels(struct ieee80211_local *local,
+					     struct sk_buff *skb,
+					     unsigned int n_channels)
+{
+	struct ieee80211_supported_band *sband;
+	unsigned int i, j;
+	u8 *pos, *len_pos;
+
+	if (!n_channels)
+		return;
+
+	pos = skb_put(skb, 2);
+	*pos++ = WLAN_EID_SUPPORTED_CHANNELS;
+	len_pos = pos;
+	*len_pos = 0;
+
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		u8 chan, first_chan = 0, count = 0;
+
+		sband = local->hw.wiphy->bands[i];
+		if (!sband)
+			continue;
+
+		for (j = 0; j < sband->n_channels; j++) {
+			u16 center_freq;
+
+			if (sband->channels[j].flags & IEEE80211_CHAN_DISABLED)
+				continue;
+
+			center_freq = sband->channels[j].center_freq;
+			chan = ieee80211_frequency_to_channel(center_freq);
+
+			if (first_chan == 0) {
+				/* first subband */
+				first_chan = chan;
+				count = 1;
+			} else if (first_chan + count == chan) {
+				/* continue the subband.
+				 * TODO: this is really only useful for 2.4,
+				 * need to add spacing considerations for other
+				 * bands as well (the definition of a subband
+				 * in the 802.11 spec. is a bit vague).
+				 */
+				count++;
+			} else {
+				/* store the subband and start a new one */
+				pos = skb_put(skb, 2);
+				*pos++ = first_chan;
+				*pos = count;
+				*len_pos += 2;
+				first_chan = chan;
+				count = 1;
+			}
+		}
+
+		if (first_chan) {
+				pos = skb_put(skb, 2);
+				*pos++ = first_chan;
+				*pos = count;
+				*len_pos += 2;
+		}
+	}
+}
+
 static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_local *local = sdata->local;
@@ -555,6 +619,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	struct ieee80211_chanctx_conf *chanctx_conf;
 	struct ieee80211_channel *chan;
 	u32 rate_flags, rates = 0;
+	unsigned int n_channels;
 
 	sdata_assert_lock(sdata);
 
@@ -597,12 +662,15 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		}
 	}
 
+	/* Get the number of enabled channels for spectrum management */
+	n_channels = ieee80211_get_num_enabled_channels(local->hw.wiphy);
+
 	skb = alloc_skb(local->hw.extra_tx_headroom +
 			sizeof(*mgmt) + /* bit too much but doesn't matter */
 			2 + assoc_data->ssid_len + /* SSID */
 			4 + rates_len + /* (extended) rates */
 			4 + /* power capability */
-			2 + 2 * sband->n_channels + /* supported channels */
+			2 + 2 * n_channels + /* supported channels */
 			2 + sizeof(struct ieee80211_ht_cap) + /* HT */
 			2 + sizeof(struct ieee80211_vht_cap) + /* VHT */
 			assoc_data->ie_len + /* extra IEs */
@@ -704,15 +772,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		*pos++ = ieee80211_chandef_max_power(&chanctx_conf->def);
 
 		/* 2. supported channels */
-		/* TODO: get this in reg domain format */
-		pos = skb_put(skb, 2 * sband->n_channels + 2);
-		*pos++ = WLAN_EID_SUPPORTED_CHANNELS;
-		*pos++ = 2 * sband->n_channels;
-		for (i = 0; i < sband->n_channels; i++) {
-			*pos++ = ieee80211_frequency_to_channel(
-					sband->channels[i].center_freq);
-			*pos++ = 1; /* one channel in the subband*/
-		}
+		ieee80211_add_supported_channels(local, skb, n_channels);
 	}
 
 	/* if present, add any custom IEs that go before HT */
-- 
1.7.10.4

RE: [PATCH 2/2] [RFC] mac80211: Add all enabled channels to the supported channels element

[Peer, Ilan]

> In the current implementation, in case that the AP supports spectrum
> management, the supported channels information element added to the
> association and re-association frames includes only the channels that where
> in the same band as that of the operating channel of the AP.
> However, the 80211-2012 specification defines in 8.4.2.20 that the supported
> channels information element should contain a list of the channel subbands
> in which the station is capable to operate.
> 
> +
> +			if (first_chan == 0) {
> +				/* first subband */
> +				first_chan = chan;
> +				count = 1;
> +			} else if (first_chan + count == chan) {
> +				/* continue the subband.
> +				 * TODO: this is really only useful for 2.4,
> +				 * need to add spacing considerations for
> other
> +				 * bands as well (the definition of a subband
> +				 * in the 802.11 spec. is a bit vague).
> +				 */

Any suggestions on how to better handle this? 

Thanks in advance :)

Ilan.

Re: [PATCH 2/2] [RFC] mac80211: Add all enabled channels to the supported channels element

[Johannes Berg]

On Tue, 2013-12-31 at 17:32 +0200, Ilan Peer wrote:


> +                       chan =
> ieee80211_frequency_to_channel(center_freq);
> +
> +                       if (first_chan == 0) {
> +                               /* first subband */
> +                               first_chan = chan;
> +                               count = 1;
> +                       } else if (first_chan + count == chan) {
> +                               /* continue the subband.
> +                                * TODO: this is really only useful
> for 2.4,
> +                                * need to add spacing considerations for other
> +                                * bands as well (the definition of a
> subband
> +                                * in the 802.11 spec. is a bit
> vague).
> +                                */
> +                               count++;

I agree this is very vague - anyone have a good idea who to ask?

As it is now, I'm not sure it's correct at all, even in the version we
have today, since different operating classes could have different
requirements. Especially since we support 5/10 MHz now, I suspect even
ieee80211_frequency_to_channel() really should be taught about operating
classes in some form?

> +	/* Get the number of enabled channels for spectrum management */
> +	n_channels = ieee80211_get_num_enabled_channels(local->hw.wiphy);

I would prefer you did this with an upper bound rather than the number
of enabled channels - we don't need a good estimate, worst case we'll
allocate a few bytes too many, but if we get it completely wrong e.g.
because the channel flags are being changed, then we could overrun the
SKB allocation, I think?

It'd also be faster to iterate only the bands and add up n_channels
rather than checking each channel's enabled bit.

johannes

RE: [PATCH 2/2] [RFC] mac80211: Add all enabled channels to the supported channels element

[Peer, Ilan]

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ICAgICAgIGlmIChmaXJzdF9jaGFuID09IDApIHsNCj4gPiArICAgICAgICAgICAgICAgICAgICAg
ICAgICAgICAgIC8qIGZpcnN0IHN1YmJhbmQgKi8NCj4gPiArICAgICAgICAgICAgICAgICAgICAg
ICAgICAgICAgIGZpcnN0X2NoYW4gPSBjaGFuOw0KPiA+ICsgICAgICAgICAgICAgICAgICAgICAg
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[PATCH 2/2 v2] [RFC]mac80211: Add all enabled channels to the supported channels element

[Ilan Peer]

In the current implementation, in case that the AP supports
spectrum management, the supported channels information element added
to the association and re-association frames includes only the channels
that where in the same band as that of the operating channel of the AP.
However, the 80211-2012 specification defines in 8.4.2.20 that the supported
channels information element should contain a list of the channel subbands
in which the station is capable to operate.

Fix this gap by include all the channels enabled by the station
(excluding channels that are marked as disabled).

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
---
 net/mac80211/mlme.c |   77 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 67 insertions(+), 10 deletions(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index fc1d824..d26f7e2 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -540,6 +540,67 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
 	ieee80211_ie_build_vht_cap(pos, &vht_cap, cap);
 }
 
+static void ieee80211_add_supported_channels(struct ieee80211_local *local,
+					     struct sk_buff *skb,
+					     unsigned int n_channels)
+{
+	struct ieee80211_supported_band *sband;
+	unsigned int i, j;
+	u8 *pos, *len_pos;
+
+	pos = skb_put(skb, 2);
+	*pos++ = WLAN_EID_SUPPORTED_CHANNELS;
+	len_pos = pos;
+	*len_pos = 0;
+
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		u8 chan, first_chan = 0, count = 0;
+
+		sband = local->hw.wiphy->bands[i];
+		if (!sband)
+			continue;
+
+		for (j = 0; j < sband->n_channels; j++) {
+			u16 center_freq;
+
+			if (sband->channels[j].flags & IEEE80211_CHAN_DISABLED)
+				continue;
+
+			center_freq = sband->channels[j].center_freq;
+			chan = ieee80211_frequency_to_channel(center_freq);
+
+			if (first_chan == 0) {
+				/* first subband */
+				first_chan = chan;
+				count = 1;
+			} else if (first_chan + count == chan) {
+				/* continue the subband.
+				 * TODO: this is really only useful for 2.4,
+				 * need to add spacing considerations for other
+				 * bands as well (the definition of a subband
+				 * in the 802.11 spec. is a bit vague).
+				 */
+				count++;
+			} else {
+				/* store the subband and start a new one */
+				pos = skb_put(skb, 2);
+				*pos++ = first_chan;
+				*pos = count;
+				*len_pos += 2;
+				first_chan = chan;
+				count = 1;
+			}
+		}
+
+		if (first_chan) {
+				pos = skb_put(skb, 2);
+				*pos++ = first_chan;
+				*pos = count;
+				*len_pos += 2;
+		}
+	}
+}
+
 static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_local *local = sdata->local;
@@ -555,6 +616,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 	struct ieee80211_chanctx_conf *chanctx_conf;
 	struct ieee80211_channel *chan;
 	u32 rate_flags, rates = 0;
+	unsigned int n_channels;
 
 	sdata_assert_lock(sdata);
 
@@ -597,12 +659,15 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		}
 	}
 
+	/* Get the number of supported channels for spectrum management */
+	n_channels = ieee80211_get_num_supported_channels(local->hw.wiphy);
+
 	skb = alloc_skb(local->hw.extra_tx_headroom +
 			sizeof(*mgmt) + /* bit too much but doesn't matter */
 			2 + assoc_data->ssid_len + /* SSID */
 			4 + rates_len + /* (extended) rates */
 			4 + /* power capability */
-			2 + 2 * sband->n_channels + /* supported channels */
+			2 + 2 * n_channels + /* supported channels */
 			2 + sizeof(struct ieee80211_ht_cap) + /* HT */
 			2 + sizeof(struct ieee80211_vht_cap) + /* VHT */
 			assoc_data->ie_len + /* extra IEs */
@@ -704,15 +769,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		*pos++ = ieee80211_chandef_max_power(&chanctx_conf->def);
 
 		/* 2. supported channels */
-		/* TODO: get this in reg domain format */
-		pos = skb_put(skb, 2 * sband->n_channels + 2);
-		*pos++ = WLAN_EID_SUPPORTED_CHANNELS;
-		*pos++ = 2 * sband->n_channels;
-		for (i = 0; i < sband->n_channels; i++) {
-			*pos++ = ieee80211_frequency_to_channel(
-					sband->channels[i].center_freq);
-			*pos++ = 1; /* one channel in the subband*/
-		}
+		ieee80211_add_supported_channels(local, skb, n_channels);
 	}
 
 	/* if present, add any custom IEs that go before HT */
-- 
1.7.10.4