[PATCH 0/3] mac80211: VHT managed mode & radiotap support

[PATCH 0/3] mac80211: VHT managed mode & radiotap support

[Johannes Berg]

For managed mode, we have to parse the VHT operation IE to
determine what the channel setting should be, and then take
into account local capabilities for the channel to use,
possibly disabling some capabilities due to regulatory.

Also add some radiotap support so we differentiate VHT from
other (HT or legacy) frames.

johannes

[PATCH 1/3] cfg80211: rework chandef checking and export it

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Some of the chandef checking that we do in cfg80211
to check if a channel is supported or not is also
needed in mac80211, so rework that a bit and export
the functions that are needed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/cfg80211.h | 21 ++++++++++--
 net/wireless/chan.c    | 92 ++++++++++++++++++++++++++++++++++----------------
 net/wireless/core.h    |  6 ----
 net/wireless/nl80211.c | 37 ++------------------
 4 files changed, 84 insertions(+), 72 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index e78db2c..a238f41 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -58,6 +58,8 @@
  * structures here describe these capabilities in detail.
  */
 
+struct wiphy;
+
 /*
  * wireless hardware capability structures
  */
@@ -388,6 +390,22 @@ cfg80211_chandef_compatible(const struct cfg80211_chan_def *chandef1,
 			    const struct cfg80211_chan_def *chandef2);
 
 /**
+ * cfg80211_chandef_valid - check if a channel definition is valid
+ * @chandef: the channel definition to check
+ */
+bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef);
+
+/**
+ * cfg80211_chandef_usable - check if secondary channels can be used
+ * @wiphy: the wiphy to validate against
+ * @chandef: the channel definition to check
+ * @prohibited_flags: the regulatory chanenl flags that must not be set
+ */
+bool cfg80211_chandef_usable(struct wiphy *wiphy,
+			     const struct cfg80211_chan_def *chandef,
+			     u32 prohibited_flags);
+
+/**
  * enum survey_info_flags - survey information flags
  *
  * @SURVEY_INFO_NOISE_DBM: noise (in dBm) was filled in
@@ -1045,9 +1063,6 @@ struct ieee80211_txq_params {
 	u8 aifs;
 };
 
-/* from net/wireless.h */
-struct wiphy;
-
 /**
  * DOC: Scanning and BSS list handling
  *
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index bf2dfd5..b5f6983 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -44,7 +44,7 @@ void cfg80211_chandef_create(struct cfg80211_chan_def *chandef,
 }
 EXPORT_SYMBOL(cfg80211_chandef_create);
 
-bool cfg80211_chan_def_valid(const struct cfg80211_chan_def *chandef)
+bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
 {
 	u32 control_freq;
 
@@ -105,6 +105,7 @@ bool cfg80211_chan_def_valid(const struct cfg80211_chan_def *chandef)
 
 	return true;
 }
+EXPORT_SYMBOL(cfg80211_chandef_valid);
 
 static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
 				  int *pri40, int *pri80)
@@ -187,9 +188,9 @@ cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
 }
 EXPORT_SYMBOL(cfg80211_chandef_compatible);
 
-bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
-				 u32 center_freq, u32 bandwidth,
-				 u32 prohibited_flags)
+static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
+					u32 center_freq, u32 bandwidth,
+					u32 prohibited_flags)
 {
 	struct ieee80211_channel *c;
 	u32 freq;
@@ -205,55 +206,88 @@ bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
 	return true;
 }
 
-static bool cfg80211_check_beacon_chans(struct wiphy *wiphy,
-					u32 center_freq, u32 bw)
+bool cfg80211_chandef_usable(struct wiphy *wiphy,
+			     const struct cfg80211_chan_def *chandef,
+			     u32 prohibited_flags)
 {
-	return cfg80211_secondary_chans_ok(wiphy, center_freq, bw,
-					   IEEE80211_CHAN_DISABLED |
-					   IEEE80211_CHAN_PASSIVE_SCAN |
-					   IEEE80211_CHAN_NO_IBSS |
-					   IEEE80211_CHAN_RADAR);
-}
+	struct ieee80211_sta_ht_cap *ht_cap;
+	struct ieee80211_sta_vht_cap *vht_cap;
+	u32 width, control_freq;
 
-bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
-			     struct cfg80211_chan_def *chandef)
-{
-	u32 width;
-	bool res;
+	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+		return false;
 
-	trace_cfg80211_reg_can_beacon(wiphy, chandef);
+	ht_cap = &wiphy->bands[chandef->chan->band]->ht_cap;
+	vht_cap = &wiphy->bands[chandef->chan->band]->vht_cap;
 
-	if (WARN_ON(!cfg80211_chan_def_valid(chandef))) {
-		trace_cfg80211_return_bool(false);
-		return false;
-	}
+	control_freq = chandef->chan->center_freq;
 
 	switch (chandef->width) {
-	case NL80211_CHAN_WIDTH_20_NOHT:
 	case NL80211_CHAN_WIDTH_20:
+		if (!ht_cap->ht_supported)
+			return false;
+	case NL80211_CHAN_WIDTH_20_NOHT:
 		width = 20;
 		break;
 	case NL80211_CHAN_WIDTH_40:
 		width = 40;
+		if (!ht_cap->ht_supported)
+			return false;
+		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
+		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
+			return false;
+		if (chandef->center_freq1 < control_freq &&
+		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
+			return false;
+		if (chandef->center_freq1 > control_freq &&
+		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
+			return false;
 		break;
-	case NL80211_CHAN_WIDTH_80:
 	case NL80211_CHAN_WIDTH_80P80:
+		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))
+			return false;
+	case NL80211_CHAN_WIDTH_80:
+		if (!vht_cap->vht_supported)
+			return false;
 		width = 80;
 		break;
 	case NL80211_CHAN_WIDTH_160:
+		if (!vht_cap->vht_supported)
+			return false;
+		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ))
+			return false;
 		width = 160;
 		break;
 	default:
 		WARN_ON_ONCE(1);
-		trace_cfg80211_return_bool(false);
 		return false;
 	}
 
-	res = cfg80211_check_beacon_chans(wiphy, chandef->center_freq1, width);
+	/* TODO: missing regulatory check on 80/160 bandwidth */
+
+	if (!cfg80211_secondary_chans_ok(wiphy, chandef->center_freq1,
+					 width, prohibited_flags))
+		return false;
+
+	if (!chandef->center_freq2)
+		return true;
+	return cfg80211_secondary_chans_ok(wiphy, chandef->center_freq2,
+					   width, prohibited_flags);
+}
+EXPORT_SYMBOL(cfg80211_chandef_usable);
+
+bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
+			     struct cfg80211_chan_def *chandef)
+{
+	bool res;
+
+	trace_cfg80211_reg_can_beacon(wiphy, chandef);
 
-	if (res && chandef->center_freq2)
-		res = cfg80211_check_beacon_chans(wiphy, chandef->center_freq2,
-						  width);
+	res = cfg80211_chandef_usable(wiphy, chandef,
+				      IEEE80211_CHAN_DISABLED |
+				      IEEE80211_CHAN_PASSIVE_SCAN |
+				      IEEE80211_CHAN_NO_IBSS |
+				      IEEE80211_CHAN_RADAR);
 
 	trace_cfg80211_return_bool(res);
 	return res;
diff --git a/net/wireless/core.h b/net/wireless/core.h
index a0c8dec..6183a0d 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -483,12 +483,6 @@ int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
 void cfg80211_update_iface_num(struct cfg80211_registered_device *rdev,
 			       enum nl80211_iftype iftype, int num);
 
-bool cfg80211_chan_def_valid(const struct cfg80211_chan_def *chandef);
-
-bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
-				 u32 center_freq, u32 bandwidth,
-				 u32 prohibited_flags);
-
 #define CFG80211_MAX_NUM_DIFFERENT_CHANNELS 10
 
 #ifdef CONFIG_CFG80211_DEVELOPER_WARNINGS
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d038fa4..ced04f2 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -1420,63 +1420,32 @@ static int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
 	ht_cap = &rdev->wiphy.bands[chandef->chan->band]->ht_cap;
 	vht_cap = &rdev->wiphy.bands[chandef->chan->band]->vht_cap;
 
-	if (!cfg80211_chan_def_valid(chandef))
+	if (!cfg80211_chandef_valid(chandef))
 		return -EINVAL;
 
 	switch (chandef->width) {
 	case NL80211_CHAN_WIDTH_20:
-		if (!ht_cap->ht_supported)
-			return -EINVAL;
 	case NL80211_CHAN_WIDTH_20_NOHT:
 		width = 20;
 		break;
 	case NL80211_CHAN_WIDTH_40:
 		width = 40;
-		/* quick early regulatory check */
-		if (chandef->center_freq1 < control_freq &&
-		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
-			return -EINVAL;
-		if (chandef->center_freq1 > control_freq &&
-		    chandef->chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
-			return -EINVAL;
-		if (!ht_cap->ht_supported)
-			return -EINVAL;
-		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
-		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
-			return -EINVAL;
 		break;
 	case NL80211_CHAN_WIDTH_80:
 		width = 80;
-		if (!vht_cap->vht_supported)
-			return -EINVAL;
 		break;
 	case NL80211_CHAN_WIDTH_80P80:
 		width = 80;
-		if (!vht_cap->vht_supported)
-			return -EINVAL;
-		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ))
-			return -EINVAL;
 		break;
 	case NL80211_CHAN_WIDTH_160:
 		width = 160;
-		if (!vht_cap->vht_supported)
-			return -EINVAL;
-		if (!(vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ))
-			return -EINVAL;
 		break;
 	default:
 		return -EINVAL;
 	}
 
-	if (!cfg80211_secondary_chans_ok(&rdev->wiphy, chandef->center_freq1,
-					 width, IEEE80211_CHAN_DISABLED))
+	if (!cfg80211_chandef_usable(&rdev->wiphy, chandef, IEEE80211_CHAN_DISABLED))
 		return -EINVAL;
-	if (chandef->center_freq2 &&
-	    !cfg80211_secondary_chans_ok(&rdev->wiphy, chandef->center_freq2,
-					 width, IEEE80211_CHAN_DISABLED))
-		return -EINVAL;
-
-	/* TODO: missing regulatory check on bandwidth */
 
 	return 0;
 }
@@ -1841,7 +1810,7 @@ static inline u64 wdev_id(struct wireless_dev *wdev)
 static int nl80211_send_chandef(struct sk_buff *msg,
 				 struct cfg80211_chan_def *chandef)
 {
-	WARN_ON(!cfg80211_chan_def_valid(chandef));
+	WARN_ON(!cfg80211_chandef_valid(chandef));
 
 	if (nla_put_u32(msg, NL80211_ATTR_WIPHY_FREQ,
 			chandef->chan->center_freq))
-- 
1.8.0

[PATCH 2/3] mac80211: support VHT association

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Determine the VHT channel from the AP's VHT operation IE
(if present) and configure the hardware to that channel
if it is supported. If channel contexts cause a channel
to not be usable, try a smaller bandwidth.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/linux/ieee80211.h  |  15 ++
 net/mac80211/ieee80211_i.h |   2 +
 net/mac80211/mlme.c        | 370 ++++++++++++++++++++++++++++++++++++---------
 3 files changed, 315 insertions(+), 72 deletions(-)

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index f9c5a78..8f690e5 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1213,6 +1213,21 @@ struct ieee80211_vht_cap {
 } __packed;
 
 /**
+ * enum ieee80211_vht_chanwidth - VHT channel width
+ * @IEEE80211_VHT_CHANWIDTH_USE_HT: use the HT operation IE to
+ *	determine the channel width (20 or 40 MHz)
+ * @IEEE80211_VHT_CHANWIDTH_80MHZ: 80 MHz bandwidth
+ * @IEEE80211_VHT_CHANWIDTH_160MHZ: 160 MHz bandwidth
+ * @IEEE80211_VHT_CHANWIDTH_80P80MHZ: 80+80 MHz bandwidth
+ */
+enum ieee80211_vht_chanwidth {
+	IEEE80211_VHT_CHANWIDTH_USE_HT		= 0,
+	IEEE80211_VHT_CHANWIDTH_80MHZ		= 1,
+	IEEE80211_VHT_CHANWIDTH_160MHZ		= 2,
+	IEEE80211_VHT_CHANWIDTH_80P80MHZ	= 3,
+};
+
+/**
  * struct ieee80211_vht_operation - VHT operation IE
  *
  * This structure is the "VHT operation element" as
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 0a8f83d..8d8bf71 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -371,6 +371,8 @@ enum ieee80211_sta_flags {
 	IEEE80211_STA_RESET_SIGNAL_AVE	= BIT(9),
 	IEEE80211_STA_DISABLE_40MHZ	= BIT(10),
 	IEEE80211_STA_DISABLE_VHT	= BIT(11),
+	IEEE80211_STA_DISABLE_80P80MHZ	= BIT(12),
+	IEEE80211_STA_DISABLE_160MHZ	= BIT(13),
 };
 
 struct ieee80211_mgd_auth_data {
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d2a4f78..e15977f 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -354,6 +354,16 @@ static void ieee80211_add_vht_ie(struct ieee80211_sub_if_data *sdata,
 	/* determine capability flags */
 	cap = vht_cap.cap;
 
+	if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_80P80MHZ) {
+		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ;
+		cap |= IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+	}
+
+	if (sdata->u.mgd.flags & IEEE80211_STA_DISABLE_160MHZ) {
+		cap &= ~IEEE80211_VHT_CAP_SHORT_GI_160;
+		cap &= ~IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ;
+	}
+
 	/* reserve and fill IE */
 	pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
 	ieee80211_ie_build_vht_cap(pos, &vht_cap, cap);
@@ -543,6 +553,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
 		offset = noffset;
 	}
 
+	if (WARN_ON_ONCE((ifmgd->flags & IEEE80211_STA_DISABLE_HT) &&
+			 !(ifmgd->flags & IEEE80211_STA_DISABLE_VHT)))
+		ifmgd->flags |= IEEE80211_STA_DISABLE_VHT;
+
 	if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT))
 		ieee80211_add_ht_ie(sdata, skb, assoc_data->ap_ht_param,
 				    sband, chan, sdata->smps_mode);
@@ -3183,23 +3197,272 @@ int ieee80211_max_network_latency(struct notifier_block *nb,
 	return 0;
 }
 
+static u32 chandef_downgrade(struct cfg80211_chan_def *c)
+{
+	u32 ret;
+	int tmp;
+
+	switch (c->width) {
+	case NL80211_CHAN_WIDTH_20:
+		c->width = NL80211_CHAN_WIDTH_20_NOHT;
+		ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		c->width = NL80211_CHAN_WIDTH_20;
+		c->center_freq1 = c->chan->center_freq;
+		ret = IEEE80211_STA_DISABLE_40MHZ |
+		      IEEE80211_STA_DISABLE_VHT;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+		tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
+		/* n_P40 */
+		tmp /= 2;
+		/* freq_P40 */
+		c->center_freq1 = c->center_freq1 - 20 + 40 * tmp;
+		c->width = NL80211_CHAN_WIDTH_40;
+		ret = IEEE80211_STA_DISABLE_VHT;
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+		c->center_freq2 = 0;
+		c->width = NL80211_CHAN_WIDTH_80;
+		ret = IEEE80211_STA_DISABLE_80P80MHZ |
+		      IEEE80211_STA_DISABLE_160MHZ;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		/* n_P20 */
+		tmp = (70 + c->chan->center_freq - c->center_freq1)/20;
+		/* n_P80 */
+		tmp /= 4;
+		c->center_freq1 = c->center_freq1 - 40 + 80 * tmp;
+		c->width = NL80211_CHAN_WIDTH_80;
+		ret = IEEE80211_STA_DISABLE_80P80MHZ |
+		      IEEE80211_STA_DISABLE_160MHZ;
+		break;
+	default:
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		WARN_ON_ONCE(1);
+		c->width = NL80211_CHAN_WIDTH_20_NOHT;
+		ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+		break;
+	}
+
+	WARN_ON_ONCE(!cfg80211_chandef_valid(c));
+
+	return ret;
+}
+
+static u32
+ieee80211_determine_chantype(struct ieee80211_sub_if_data *sdata,
+			     struct ieee80211_supported_band *sband,
+			     struct ieee80211_channel *channel,
+			     const struct ieee80211_ht_operation *ht_oper,
+			     const struct ieee80211_vht_operation *vht_oper,
+			     struct cfg80211_chan_def *chandef)
+{
+	struct cfg80211_chan_def vht_chandef;
+	u32 ht_cfreq, ret;
+
+	chandef->chan = channel;
+	chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
+	chandef->center_freq1 = channel->center_freq;
+	chandef->center_freq2 = 0;
+
+	if (!ht_oper || !sband->ht_cap.ht_supported) {
+		ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	chandef->width = NL80211_CHAN_WIDTH_20;
+
+	ht_cfreq = ieee80211_channel_to_frequency(ht_oper->primary_chan,
+						  channel->band);
+	/* check that channel matches the right operating channel */
+	if (channel->center_freq != ht_cfreq) {
+		/*
+		 * It's possible that some APs are confused here;
+		 * Netgear WNDR3700 sometimes reports 4 higher than
+		 * the actual channel in association responses, but
+		 * since we look at probe response/beacon data here
+		 * it should be OK.
+		 */
+		sdata_info(sdata,
+			   "Wrong control channel: center-freq: %d ht-cfreq: %d ht->primary_chan: %d band: %d - Disabling HT\n",
+			   channel->center_freq, ht_cfreq,
+			   ht_oper->primary_chan, channel->band);
+		ret = IEEE80211_STA_DISABLE_HT | IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	/* check 40 MHz support, if we have it */
+	if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
+		switch (ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
+		case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
+			chandef->width = NL80211_CHAN_WIDTH_40;
+			chandef->center_freq1 += 10;
+			break;
+		case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
+			chandef->width = NL80211_CHAN_WIDTH_40;
+			chandef->center_freq1 -= 10;
+			break;
+		}
+	} else {
+		/* 40 MHz (and 80 MHz) must be supported for VHT */
+		ret = IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	if (!vht_oper || !sband->vht_cap.vht_supported) {
+		ret = IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	vht_chandef.chan = channel;
+	vht_chandef.center_freq1 =
+		ieee80211_channel_to_frequency(vht_oper->center_freq_seg1_idx,
+					       channel->band);
+	vht_chandef.center_freq2 = 0;
+
+	if (vht_oper->center_freq_seg2_idx)
+		vht_chandef.center_freq2 =
+			ieee80211_channel_to_frequency(
+				vht_oper->center_freq_seg2_idx,
+				channel->band);
+
+	switch (vht_oper->chan_width) {
+	case IEEE80211_VHT_CHANWIDTH_USE_HT:
+		vht_chandef.width = chandef->width;
+		break;
+	case IEEE80211_VHT_CHANWIDTH_80MHZ:
+		vht_chandef.width = NL80211_CHAN_WIDTH_80;
+		break;
+	case IEEE80211_VHT_CHANWIDTH_160MHZ:
+		vht_chandef.width = NL80211_CHAN_WIDTH_160;
+		break;
+	case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
+		vht_chandef.width = NL80211_CHAN_WIDTH_80P80;
+		break;
+	default:
+		sdata_info(sdata,
+			   "AP VHT operation IE has invalid channel width (%d), disable VHT\n",
+			   vht_oper->chan_width);
+		ret = IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	if (!cfg80211_chandef_valid(&vht_chandef)) {
+		sdata_info(sdata,
+			   "AP VHT information is invalid, disable VHT\n");
+		ret = IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	if (cfg80211_chandef_identical(chandef, &vht_chandef)) {
+		ret = 0;
+		goto out;
+	}
+
+	if (!cfg80211_chandef_compatible(chandef, &vht_chandef)) {
+		sdata_info(sdata,
+			   "AP VHT information doesn't match HT, disable VHT\n");
+		ret = IEEE80211_STA_DISABLE_VHT;
+		goto out;
+	}
+
+	*chandef = vht_chandef;
+
+	ret = 0;
+
+	while (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef,
+					IEEE80211_CHAN_DISABLED)) {
+		if (WARN_ON(chandef->width == NL80211_CHAN_WIDTH_20_NOHT)) {
+			ret = IEEE80211_STA_DISABLE_HT |
+			      IEEE80211_STA_DISABLE_VHT;
+			goto out;
+		}
+
+		ret = chandef_downgrade(chandef);
+	}
+
+	if (chandef->width != vht_chandef.width)
+		sdata_info(sdata,
+			   "local regulatory prevented using AP HT/VHT configuration, downgraded\n");
+
+out:
+	WARN_ON_ONCE(!cfg80211_chandef_valid(chandef));
+	return ret;
+}
+
+static u8 ieee80211_ht_vht_rx_chains(struct ieee80211_sub_if_data *sdata,
+				     struct cfg80211_bss *cbss)
+{
+	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+	const u8 *ht_cap_ie, *vht_cap_ie;
+	const struct ieee80211_ht_cap *ht_cap;
+	const struct ieee80211_vht_cap *vht_cap;
+	u8 chains = 1;
+
+	if (ifmgd->flags & IEEE80211_STA_DISABLE_HT)
+		return chains;
+
+	ht_cap_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY,
+				     cbss->information_elements,
+				     cbss->len_information_elements);
+	if (ht_cap_ie && ht_cap_ie[1] >= sizeof(*ht_cap)) {
+		ht_cap = (void *)(ht_cap_ie + 2);
+		chains = ieee80211_mcs_to_chains(&ht_cap->mcs);
+		/*
+		 * TODO: use "Tx Maximum Number Spatial Streams Supported" and
+		 *	 "Tx Unequal Modulation Supported" fields.
+		 */
+		
+	}
+
+	if (ifmgd->flags & IEEE80211_STA_DISABLE_VHT)
+		return chains;
+
+
+	vht_cap_ie = cfg80211_find_ie(WLAN_EID_VHT_CAPABILITY,
+				      cbss->information_elements,
+				      cbss->len_information_elements);
+	if (vht_cap_ie && vht_cap_ie[1] >= sizeof(*vht_cap)) {
+		u8 nss;
+		u16 tx_mcs_map;
+
+		vht_cap = (void *)(vht_cap_ie + 2);
+		tx_mcs_map = le16_to_cpu(vht_cap->supp_mcs.tx_mcs_map);
+		for (nss = 8; nss > 0; nss--) {
+			if (((tx_mcs_map >> (2 * (nss - 1))) & 3) !=
+					IEEE80211_VHT_MCS_NOT_SUPPORTED)
+				break;
+		}
+		/* TODO: use "Tx Highest Supported Long GI Data Rate" field? */
+		chains = max(chains, nss);
+	}
+
+	return chains;
+}
+
 static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 				  struct cfg80211_bss *cbss)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
-	int ht_cfreq;
-	enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
-	const u8 *ht_oper_ie;
 	const struct ieee80211_ht_operation *ht_oper = NULL;
+	const struct ieee80211_vht_operation *vht_oper = NULL;
 	struct ieee80211_supported_band *sband;
 	struct cfg80211_chan_def chandef;
+	int ret;
 
 	sband = local->hw.wiphy->bands[cbss->channel->band];
 
-	ifmgd->flags &= ~IEEE80211_STA_DISABLE_40MHZ;
+	ifmgd->flags &= ~(IEEE80211_STA_DISABLE_40MHZ |
+			  IEEE80211_STA_DISABLE_80P80MHZ |
+			  IEEE80211_STA_DISABLE_160MHZ);
+
+	if (!(ifmgd->flags & IEEE80211_STA_DISABLE_HT) &&
+	    sband->ht_cap.ht_supported) {
+		const u8 *ht_oper_ie;
 
-	if (sband->ht_cap.ht_supported) {
 		ht_oper_ie = cfg80211_find_ie(WLAN_EID_HT_OPERATION,
 					      cbss->information_elements,
 					      cbss->len_information_elements);
@@ -3207,82 +3470,45 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 			ht_oper = (void *)(ht_oper_ie + 2);
 	}
 
-	if (ht_oper) {
-		ht_cfreq = ieee80211_channel_to_frequency(ht_oper->primary_chan,
-							  cbss->channel->band);
-		/* check that channel matches the right operating channel */
-		if (cbss->channel->center_freq != ht_cfreq) {
-			/*
-			 * It's possible that some APs are confused here;
-			 * Netgear WNDR3700 sometimes reports 4 higher than
-			 * the actual channel in association responses, but
-			 * since we look at probe response/beacon data here
-			 * it should be OK.
-			 */
+	if (!(ifmgd->flags & IEEE80211_STA_DISABLE_VHT) &&
+	    sband->vht_cap.vht_supported) {
+		const u8 *vht_oper_ie;
+
+		vht_oper_ie = cfg80211_find_ie(WLAN_EID_VHT_OPERATION,
+					       cbss->information_elements,
+					       cbss->len_information_elements);
+		if (vht_oper_ie && vht_oper_ie[1] >= sizeof(*vht_oper))
+			vht_oper = (void *)(vht_oper_ie + 2);
+		if (vht_oper && !ht_oper) {
+			vht_oper = NULL;
 			sdata_info(sdata,
-				   "Wrong control channel: center-freq: %d ht-cfreq: %d ht->primary_chan: %d band: %d - Disabling HT\n",
-				   cbss->channel->center_freq,
-				   ht_cfreq, ht_oper->primary_chan,
-				   cbss->channel->band);
-			ht_oper = NULL;
+				   "AP advertised VHT without HT, disabling both\n");
+			sdata->flags |= IEEE80211_STA_DISABLE_HT;
+			sdata->flags |= IEEE80211_STA_DISABLE_VHT;
 		}
 	}
 
-	if (ht_oper) {
-		/*
-		 * cfg80211 already verified that the channel itself can
-		 * be used, but it didn't check that we can do the right
-		 * HT type, so do that here as well. If HT40 isn't allowed
-		 * on this channel, disable 40 MHz operation.
-		 */
-		const u8 *ht_cap_ie;
-		const struct ieee80211_ht_cap *ht_cap;
-		u8 chains = 1;
-
-		channel_type = NL80211_CHAN_HT20;
-
-		if (sband->ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) {
-			switch (ht_oper->ht_param &
-					IEEE80211_HT_PARAM_CHA_SEC_OFFSET) {
-			case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
-				if (cbss->channel->flags &
-						IEEE80211_CHAN_NO_HT40PLUS)
-					ifmgd->flags |=
-						IEEE80211_STA_DISABLE_40MHZ;
-				else
-					channel_type = NL80211_CHAN_HT40PLUS;
-				break;
-			case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
-				if (cbss->channel->flags &
-						IEEE80211_CHAN_NO_HT40MINUS)
-					ifmgd->flags |=
-						IEEE80211_STA_DISABLE_40MHZ;
-				else
-					channel_type = NL80211_CHAN_HT40MINUS;
-				break;
-			}
-		}
+	ifmgd->flags |= ieee80211_determine_chantype(sdata, sband,
+						     cbss->channel,
+						     ht_oper, vht_oper,
+						     &chandef);
 
-		ht_cap_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY,
-					     cbss->information_elements,
-					     cbss->len_information_elements);
-		if (ht_cap_ie && ht_cap_ie[1] >= sizeof(*ht_cap)) {
-			ht_cap = (void *)(ht_cap_ie + 2);
-			chains = ieee80211_mcs_to_chains(&ht_cap->mcs);
-		}
-		sdata->needed_rx_chains = min(chains, local->rx_chains);
-	} else {
-		sdata->needed_rx_chains = 1;
-		sdata->u.mgd.flags |= IEEE80211_STA_DISABLE_HT;
-	}
+	sdata->needed_rx_chains = min(ieee80211_ht_vht_rx_chains(sdata, cbss),
+				      local->rx_chains);
 
 	/* will change later if needed */
 	sdata->smps_mode = IEEE80211_SMPS_OFF;
 
-	ieee80211_vif_release_channel(sdata);
-	cfg80211_chandef_create(&chandef, cbss->channel, channel_type);
-	return ieee80211_vif_use_channel(sdata, &chandef,
-					 IEEE80211_CHANCTX_SHARED);
+	/*
+	 * If this fails (possibly due to channel context sharing
+	 * on incompatible channels, e.g. 80+80 and 160 sharing the
+	 * same control channel) try to use a smaller bandwidth.
+	 */
+	ret = ieee80211_vif_use_channel(sdata, &chandef,
+					IEEE80211_CHANCTX_SHARED);
+	while (ret && chandef.width != NL80211_CHAN_WIDTH_20_NOHT)
+		ifmgd->flags |= chandef_downgrade(&chandef);
+	return ret;
 }
 
 static int ieee80211_prep_connection(struct ieee80211_sub_if_data *sdata,
-- 
1.8.0

[PATCH 3/3] mac80211: support (partial) VHT radiotap information

[Johannes Berg]

From: Johannes Berg <johannes.berg@intel.com>

Add some information that we have about VHT to radiotap.
This at least lets one see the MCS and NSS information.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 include/net/ieee80211_radiotap.h | 24 ++++++++++++++++++++++++
 include/net/mac80211.h           |  5 +++++
 net/mac80211/main.c              |  2 ++
 net/mac80211/rx.c                | 40 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+)

diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index 7f0df13..c399963 100644
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -186,6 +186,10 @@ struct ieee80211_radiotap_header {
  * IEEE80211_RADIOTAP_AMPDU_STATUS	u32, u16, u8, u8	unitless
  *
  *	Contains the AMPDU information for the subframe.
+ *
+ * IEEE80211_RADIOTAP_VHT	u16, u8, u8, u8[4], u8, u8, u16
+ *
+ *	Contains VHT information about this frame.
  */
 enum ieee80211_radiotap_type {
 	IEEE80211_RADIOTAP_TSFT = 0,
@@ -209,6 +213,7 @@ enum ieee80211_radiotap_type {
 
 	IEEE80211_RADIOTAP_MCS = 19,
 	IEEE80211_RADIOTAP_AMPDU_STATUS = 20,
+	IEEE80211_RADIOTAP_VHT = 21,
 
 	/* valid in every it_present bitmap, even vendor namespaces */
 	IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
@@ -282,6 +287,25 @@ enum ieee80211_radiotap_type {
 #define IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR		0x0010
 #define IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN	0x0020
 
+/* For IEEE80211_RADIOTAP_VHT */
+#define IEEE80211_RADIOTAP_VHT_KNOWN_STBC			0x0001
+#define IEEE80211_RADIOTAP_VHT_KNOWN_TXOP_PS_NA			0x0002
+#define IEEE80211_RADIOTAP_VHT_KNOWN_GI				0x0004
+#define IEEE80211_RADIOTAP_VHT_KNOWN_SGI_NSYM_DIS		0x0008
+#define IEEE80211_RADIOTAP_VHT_KNOWN_LDPC_EXTRA_OFDM_SYM	0x0010
+#define IEEE80211_RADIOTAP_VHT_KNOWN_BEAMFORMED			0x0020
+#define IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH			0x0040
+#define IEEE80211_RADIOTAP_VHT_KNOWN_GROUP_ID			0x0080
+#define IEEE80211_RADIOTAP_VHT_KNOWN_PARTIAL_AID		0x0100
+
+#define IEEE80211_RADIOTAP_VHT_FLAG_STBC			0x01
+#define IEEE80211_RADIOTAP_VHT_FLAG_TXOP_PS_NA			0x02
+#define IEEE80211_RADIOTAP_VHT_FLAG_SGI				0x04
+#define IEEE80211_RADIOTAP_VHT_FLAG_SGI_NSYM_M10_9		0x08
+#define IEEE80211_RADIOTAP_VHT_FLAG_LDPC_EXTRA_OFDM_SYM		0x10
+#define IEEE80211_RADIOTAP_VHT_FLAG_BEAMFORMED			0x20
+
+
 /* helpers */
 static inline int ieee80211_get_radiotap_len(unsigned char *data)
 {
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index db7680a..e806f1d 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1473,6 +1473,10 @@ enum ieee80211_hw_flags {
  *	include _FMT. Use %IEEE80211_RADIOTAP_MCS_HAVE_* values, only
  *	adding _BW is supported today.
  *
+ * @radiotap_vht_details: lists which VHT MCS information the HW reports,
+ *	the default is _GI | _BANDWIDTH.
+ *	Use the %IEEE80211_RADIOTAP_VHT_KNOWN_* values.
+ *
  * @netdev_features: netdev features to be set in each netdev created
  *	from this HW. Note only HW checksum features are currently
  *	compatible with mac80211. Other feature bits will be rejected.
@@ -1499,6 +1503,7 @@ struct ieee80211_hw {
 	u8 max_tx_aggregation_subframes;
 	u8 offchannel_tx_hw_queue;
 	u8 radiotap_mcs_details;
+	u16 radiotap_vht_details;
 	netdev_features_t netdev_features;
 };
 
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 6e93340..c4ed83b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -638,6 +638,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	local->hw.radiotap_mcs_details = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
 					 IEEE80211_RADIOTAP_MCS_HAVE_GI |
 					 IEEE80211_RADIOTAP_MCS_HAVE_BW;
+	local->hw.radiotap_vht_details = IEEE80211_RADIOTAP_VHT_KNOWN_GI |
+					 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
 	local->user_power_level = IEEE80211_UNSET_POWER_LEVEL;
 	wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 825f33c..9b13b8b 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -111,6 +111,11 @@ ieee80211_rx_radiotap_space(struct ieee80211_local *local,
 		len += 8;
 	}
 
+	if (status->flag & RX_FLAG_VHT) {
+		len = ALIGN(len, 2);
+		len += 12;
+	}
+
 	if (status->vendor_radiotap_len) {
 		if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
 			status->vendor_radiotap_align = 1;
@@ -297,6 +302,41 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 		*pos++ = 0;
 	}
 
+	if (status->flag & RX_FLAG_VHT) {
+		u16 known = local->hw.radiotap_vht_details;
+
+		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
+		/* known field - how to handle 80+80? */
+		if (status->flag & RX_FLAG_80P80MHZ)
+			known &= ~IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
+		put_unaligned_le16(known, pos);
+		pos += 2;
+		/* flags */
+		if (status->flag & RX_FLAG_SHORT_GI)
+			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
+		pos++;
+		/* bandwidth */
+		if (status->flag & RX_FLAG_80MHZ)
+			*pos++ = 4;
+		else if (status->flag & RX_FLAG_80P80MHZ)
+			*pos++ = 0; /* marked not known above */
+		else if (status->flag & RX_FLAG_160MHZ)
+			*pos++ = 11;
+		else if (status->flag & RX_FLAG_40MHZ)
+			*pos++ = 1;
+		else /* 20 MHz */
+			*pos++ = 0;
+		/* MCS/NSS */
+		*pos = (status->rate_idx << 4) | status->vht_nss;
+		pos += 4;
+		/* coding field */
+		pos++;
+		/* group ID */
+		pos++;
+		/* partial_aid */
+		pos += 2;
+	}
+
 	if (status->vendor_radiotap_len) {
 		/* ensure 2 byte alignment for the vendor field as required */
 		if ((pos - (u8 *)rthdr) & 1)
-- 
1.8.0

Re: [PATCH 2/3] mac80211: support VHT association

[Mahesh Palivela]

On 11/26/2012 07:55 PM, Johannes Berg wrote:
> +static u8 ieee80211_ht_vht_rx_chains(struct ieee80211_sub_if_data *sdata,
> +				     struct cfg80211_bss *cbss)
> +{
> +	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
> +	const u8 *ht_cap_ie, *vht_cap_ie;
> +	const struct ieee80211_ht_cap *ht_cap;
> +	const struct ieee80211_vht_cap *vht_cap;
> +	u8 chains = 1;
> +
> +	if (ifmgd->flags & IEEE80211_STA_DISABLE_HT)
> +		return chains;
> +
> +	ht_cap_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY,
> +				     cbss->information_elements,
> +				     cbss->len_information_elements);
> +	if (ht_cap_ie && ht_cap_ie[1] >= sizeof(*ht_cap)) {
> +		ht_cap = (void *)(ht_cap_ie + 2);
> +		chains = ieee80211_mcs_to_chains(&ht_cap->mcs);
> +		/*
> +		 * TODO: use "Tx Maximum Number Spatial Streams Supported" and
> +		 *	 "Tx Unequal Modulation Supported" fields.
> +		 */
> +		
> +	}
> +
> +	if (ifmgd->flags & IEEE80211_STA_DISABLE_VHT)
> +		return chains;
> +
> +
> +	vht_cap_ie = cfg80211_find_ie(WLAN_EID_VHT_CAPABILITY,
> +				      cbss->information_elements,
> +				      cbss->len_information_elements);
> +	if (vht_cap_ie && vht_cap_ie[1] >= sizeof(*vht_cap)) {
> +		u8 nss;
> +		u16 tx_mcs_map;
> +
> +		vht_cap = (void *)(vht_cap_ie + 2);
> +		tx_mcs_map = le16_to_cpu(vht_cap->supp_mcs.tx_mcs_map);

Guess we should take rx_mcs_map as we are determining vht_rx_chains?

Thanks,
Mahesh

Re: [PATCH 2/3] mac80211: support VHT association

[Johannes Berg]

On Tue, 2012-11-27 at 17:42 +0530, Mahesh Palivela wrote:

> > +		vht_cap = (void *)(vht_cap_ie + 2);
> > +		tx_mcs_map = le16_to_cpu(vht_cap->supp_mcs.tx_mcs_map);
> 
> Guess we should take rx_mcs_map as we are determining vht_rx_chains?

No, when we determine our needed RX chains, we need to know what the AP
can transmit to us, not what the AP can receive.

johannes

Re: [PATCH 0/3] mac80211: VHT managed mode & radiotap support

[Johannes Berg]

On Mon, 2012-11-26 at 15:25 +0100, Johannes Berg wrote:
> For managed mode, we have to parse the VHT operation IE to
> determine what the channel setting should be, and then take
> into account local capabilities for the channel to use,
> possibly disabling some capabilities due to regulatory.
> 
> Also add some radiotap support so we differentiate VHT from
> other (HT or legacy) frames.

Applied, with a few whitespace changes.

johannes