[RFC 0/2] mac80211: add support for ht_caps mcs rxmask override

[RFC 0/2] mac80211: add support for ht_caps mcs rxmask override

[Cedric DEBARGE]

This patchset allows the ht_caps mcs rxmask to be defined on the fly.
It applies the given rxmask to all available bands.

This is actually limited to radio cards without internal rc.

Cedric DEBARGE (2):
  cfg80211: add support for ht_caps mcs rxmask override
  nl80211: add nl attribute to set ht_caps mcs rxmask override

 include/net/cfg80211.h       |  7 ++++++
 include/uapi/linux/nl80211.h |  5 +++++
 net/mac80211/cfg.c           | 48 +++++++++++++++++++++++++++++++++++++++
 net/mac80211/main.c          | 53 +++++++++++++++++++++++++++++++++++++-------
 net/wireless/nl80211.c       | 18 +++++++++++++++
 net/wireless/rdev-ops.h      | 11 +++++++++
 net/wireless/trace.h         | 15 +++++++++++++
 7 files changed, 149 insertions(+), 8 deletions(-)

-- 
1.9.1

[RFC 1/2] cfg80211: add support for ht_caps mcs rxmask override

[Cedric DEBARGE]

Allows the ht_caps mcs rxmask to be defined on the fly.
In this implementation, the given rxmask is applied to
every band available.
This is only applicable for radio cards without internal rc.

Signed-off-by: Cedric Debarge <cedric.debarge@acksys.fr>
---
 include/net/cfg80211.h |  7 +++++++
 net/mac80211/cfg.c     | 48 +++++++++++++++++++++++++++++++++++++++++++++
 net/mac80211/main.c    | 53 ++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 100 insertions(+), 8 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 9e1b24c..257404b 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2500,6 +2500,8 @@ struct cfg80211_qos_map {
  *	and returning to the base channel for communication with the AP.
  * @tdls_cancel_channel_switch: Stop channel-switching with a TDLS peer. Both
  *	peers must be on the base channel when the call completes.
+ *
+ * @set_htcap_rxmask: Override hardware capabilities for ht_caps mcs rxmask.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -2765,6 +2767,8 @@ struct cfg80211_ops {
 	void	(*tdls_cancel_channel_switch)(struct wiphy *wiphy,
 					      struct net_device *dev,
 					      const u8 *addr);
+
+	int (*set_htcap_rxmask)(struct wiphy *wiphy, uint8_t *rxmask);
 };
 
 /*
@@ -3121,6 +3125,8 @@ struct wiphy_vendor_command {
  *	wiphy is theirs, e.g. in global notifiers
  * @bands: information about bands/channels supported by this device
  *
+ * @init_bands: save of the originals information about bands.
+ *
  * @mgmt_stypes: bitmasks of frame subtypes that can be subscribed to or
  *	transmitted through nl80211, points to an array indexed by interface
  *	type
@@ -3266,6 +3272,7 @@ struct wiphy {
 	const void *privid;
 
 	struct ieee80211_supported_band *bands[IEEE80211_NUM_BANDS];
+	struct ieee80211_supported_band *init_bands[IEEE80211_NUM_BANDS];
 
 	/* Lets us get back the wiphy on the callback */
 	void (*reg_notifier)(struct wiphy *wiphy,
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 66d22de..daa415b 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3350,6 +3350,53 @@ static int ieee80211_del_tx_ts(struct wiphy *wiphy, struct net_device *dev,
 	return -ENOENT;
 }
 
+static int ieee80211_set_htcap_rxmask(struct wiphy *wiphy, uint8_t *rxmask)
+{
+	struct ieee80211_local *local = wiphy_priv(wiphy);
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_supported_band *iband;
+	int blank = 1;
+	int empty;
+	int i;
+
+	if (ieee80211_hw_check(&local->hw, HAS_RATE_CONTROL))
+		return -EINVAL;
+
+	mutex_lock(&local->iflist_mtx);
+	empty = list_empty(&local->interfaces);
+	mutex_unlock(&local->iflist_mtx);
+
+	if (!empty)
+		return -EBUSY;
+
+	for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
+		if (rxmask[i]) {
+			blank = 0;
+			break;
+		}
+
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		int j;
+
+		sband = wiphy->bands[i];
+		iband = wiphy->init_bands[i];
+
+		if (!iband)
+			continue;
+
+		for (j = 0; j < IEEE80211_HT_MCS_MASK_LEN; j++) {
+			if (blank)
+				sband->ht_cap.mcs.rx_mask[j] =
+						iband->ht_cap.mcs.rx_mask[j];
+			else
+				sband->ht_cap.mcs.rx_mask[j] = rxmask[j] &
+						iband->ht_cap.mcs.rx_mask[j];
+		}
+	}
+
+	return 0;
+}
+
 const struct cfg80211_ops mac80211_config_ops = {
 	.add_virtual_intf = ieee80211_add_iface,
 	.del_virtual_intf = ieee80211_del_iface,
@@ -3435,4 +3482,5 @@ const struct cfg80211_ops mac80211_config_ops = {
 	.set_ap_chanwidth = ieee80211_set_ap_chanwidth,
 	.add_tx_ts = ieee80211_add_tx_ts,
 	.del_tx_ts = ieee80211_del_tx_ts,
+	.set_htcap_rxmask = ieee80211_set_htcap_rxmask,
 };
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 6bcf0fa..138f1e4 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -789,15 +789,37 @@ static int ieee80211_init_cipher_suites(struct ieee80211_local *local)
 	return 0;
 }
 
+static int ieee80211_alloc_init_bands(struct wiphy *wiphy)
+{
+	int i;
+
+	memset(wiphy->init_bands, 0, IEEE80211_NUM_BANDS);
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		if (!wiphy->bands[i])
+			continue;
+
+		wiphy->init_bands[i] = kzalloc(sizeof(*wiphy->init_bands[i]),
+					       GFP_KERNEL);
+		if (!wiphy->init_bands[i])
+			return -ENOMEM;
+
+		memcpy(wiphy->init_bands[i], wiphy->bands[i],
+		       sizeof(struct ieee80211_supported_band));
+	}
+
+	return 0;
+}
+
 int ieee80211_register_hw(struct ieee80211_hw *hw)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
-	int result, i;
-	enum ieee80211_band band;
+	struct cfg80211_chan_def dflt_chandef = {};
+	netdev_features_t feature_whitelist;
 	int channels, max_bitrates;
+	enum ieee80211_band band;
 	bool supp_ht, supp_vht;
-	netdev_features_t feature_whitelist;
-	struct cfg80211_chan_def dflt_chandef = {};
+	int result = 0;
+	int i;
 
 	if (ieee80211_hw_check(hw, QUEUE_CONTROL) &&
 	    (local->hw.offchannel_tx_hw_queue == IEEE80211_INVAL_HW_QUEUE ||
@@ -857,6 +879,11 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 
 	local->rx_chains = 1;
 
+	if (ieee80211_alloc_init_bands(hw->wiphy)) {
+		result = -ENOMEM;
+		goto fail_sband_init;
+	}
+
 	/*
 	 * generic code guarantees at least one band,
 	 * set this very early because much code assumes
@@ -919,14 +946,18 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 
 		for (j = 0; j < c->n_limits; j++)
 			if ((c->limits[j].types & BIT(NL80211_IFTYPE_ADHOC)) &&
-			    c->limits[j].max > 1)
-				return -EINVAL;
+			    c->limits[j].max > 1) {
+				result = -EINVAL;
+				goto fail_sband_init;
+			}
 	}
 
 	local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) +
 				      sizeof(void *) * channels, GFP_KERNEL);
-	if (!local->int_scan_req)
-		return -ENOMEM;
+	if (!local->int_scan_req) {
+		result = -ENOMEM;
+		goto fail_sband_init;
+	}
 
 	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 		if (!local->hw.wiphy->bands[band])
@@ -1120,6 +1151,9 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	if (local->wiphy_ciphers_allocated)
 		kfree(local->hw.wiphy->cipher_suites);
 	kfree(local->int_scan_req);
+ fail_sband_init:
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++)
+		kfree(hw->wiphy->init_bands[i]);
 	return result;
 }
 EXPORT_SYMBOL(ieee80211_register_hw);
@@ -1127,6 +1161,7 @@ EXPORT_SYMBOL(ieee80211_register_hw);
 void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	int i;
 
 	tasklet_kill(&local->tx_pending_tasklet);
 	tasklet_kill(&local->tasklet);
@@ -1170,6 +1205,8 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 	ieee80211_wep_free(local);
 	ieee80211_led_exit(local);
 	kfree(local->int_scan_req);
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++)
+		kfree(hw->wiphy->init_bands[i]);
 }
 EXPORT_SYMBOL(ieee80211_unregister_hw);
 
-- 
1.9.1

[RFC 2/2] nl80211: add nl attribute to set ht_caps mcs rxmask override

[Cedric DEBARGE]

This adds the NL80211_ATTR_WIPHY_HTCAP_RXMASK attribute to
NL80211_CMD_SET_WIPHY in order for the user to specify the ht_caps mcs
rxmask.

Signed-off-by: Cedric Debarge <cedric.debarge@acksys.fr>
---
 include/uapi/linux/nl80211.h |  5 +++++
 net/wireless/nl80211.c       | 18 ++++++++++++++++++
 net/wireless/rdev-ops.h      | 11 +++++++++++
 net/wireless/trace.h         | 15 +++++++++++++++
 4 files changed, 49 insertions(+)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 7758969..50a53d8 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1794,6 +1794,9 @@ enum nl80211_commands {
  *	connecting to a PCP, and in %NL80211_CMD_START_AP to start
  *	a PCP instead of AP. Relevant for DMG networks only.
  *
+ * @NL80211_ATTR_WIPHY_HTCAP_RXMASK: Override hardware capabilities for ht_caps
+ *	mcs rxmask.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2170,6 +2173,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PBSS,
 
+	NL80211_ATTR_WIPHY_HTCAP_RXMASK,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 268cb49..ef5ec8b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -402,6 +402,9 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 },
 	[NL80211_ATTR_REG_INDOOR] = { .type = NLA_FLAG },
 	[NL80211_ATTR_PBSS] = { .type = NLA_FLAG },
+	[NL80211_ATTR_WIPHY_HTCAP_RXMASK] = { .type = NLA_BINARY,
+					      .len = IEEE80211_HT_MCS_MASK_LEN
+	},
 };
 
 /* policy for the key attributes */
@@ -2243,6 +2246,21 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
 			return result;
 	}
 
+	if (info->attrs[NL80211_ATTR_WIPHY_HTCAP_RXMASK]) {
+		u8 rxmask[IEEE80211_HT_MCS_MASK_LEN];
+
+		if (wdev)
+			return -EOPNOTSUPP;
+
+		memcpy(rxmask,
+		       nla_data(info->attrs[NL80211_ATTR_WIPHY_HTCAP_RXMASK]),
+		       IEEE80211_HT_MCS_MASK_LEN);
+
+		result = rdev_set_htcap_rxmask(rdev, rxmask);
+		if (result)
+			return result;
+	}
+
 	changed = 0;
 
 	if (info->attrs[NL80211_ATTR_WIPHY_RETRY_SHORT]) {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 8ae0c04..488adb9 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -1071,4 +1071,15 @@ rdev_set_coalesce(struct cfg80211_registered_device *rdev,
 	trace_rdev_return_int(&rdev->wiphy, ret);
 	return ret;
 }
+
+static inline int
+rdev_set_htcap_rxmask(struct cfg80211_registered_device *rdev, uint8_t *rxmask)
+{
+	int ret;
+
+	trace_rdev_set_htcap_rxmask(&rdev->wiphy, rxmask);
+	ret = rdev->ops->set_htcap_rxmask(&rdev->wiphy, rxmask);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
 #endif /* __CFG80211_RDEV_OPS */
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 09b242b..d7c8c3c 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2120,6 +2120,21 @@ TRACE_EVENT(rdev_tdls_cancel_channel_switch,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(addr))
 );
 
+TRACE_EVENT(rdev_set_htcap_rxmask,
+	TP_PROTO(struct wiphy *wiphy, uint8_t *rxmask),
+	TP_ARGS(wiphy, rxmask),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		__array(uint8_t, rxmask, IEEE80211_HT_MCS_MASK_LEN)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		memcpy(__entry->rxmask, rxmask, IEEE80211_HT_MCS_MASK_LEN);
+	),
+	TP_printk(WIPHY_PR_FMT ", %*ph",
+		  WIPHY_PR_ARG, IEEE80211_HT_MCS_MASK_LEN, &__entry->rxmask[0])
+);
+
 /*************************************************************
  *	     cfg80211 exported functions traces		     *
  *************************************************************/
-- 
1.9.1

[RFC 2/2] nl80211: add nl attribute to set ht_caps mcs rxmask override

[Cedric DEBARGE]

This adds the NL80211_ATTR_WIPHY_HTCAP_RXMASK attribute to
NL80211_CMD_SET_WIPHY in order for the user to specify the ht_caps mcs
rxmask.

Signed-off-by: Cedric Debarge <cedric.debarge-eYuUwLwYA0BQFI55V6+gNQ@public.gmane.org>
---
 include/uapi/linux/nl80211.h |  5 +++++
 net/wireless/nl80211.c       | 18 ++++++++++++++++++
 net/wireless/rdev-ops.h      | 11 +++++++++++
 net/wireless/trace.h         | 15 +++++++++++++++
 4 files changed, 49 insertions(+)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 7758969..50a53d8 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1794,6 +1794,9 @@ enum nl80211_commands {
  *	connecting to a PCP, and in %NL80211_CMD_START_AP to start
  *	a PCP instead of AP. Relevant for DMG networks only.
  *
+ * @NL80211_ATTR_WIPHY_HTCAP_RXMASK: Override hardware capabilities for ht_caps
+ *	mcs rxmask.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2170,6 +2173,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PBSS,
 
+	NL80211_ATTR_WIPHY_HTCAP_RXMASK,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 268cb49..ef5ec8b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -402,6 +402,9 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 },
 	[NL80211_ATTR_REG_INDOOR] = { .type = NLA_FLAG },
 	[NL80211_ATTR_PBSS] = { .type = NLA_FLAG },
+	[NL80211_ATTR_WIPHY_HTCAP_RXMASK] = { .type = NLA_BINARY,
+					      .len = IEEE80211_HT_MCS_MASK_LEN
+	},
 };
 
 /* policy for the key attributes */
@@ -2243,6 +2246,21 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
 			return result;
 	}
 
+	if (info->attrs[NL80211_ATTR_WIPHY_HTCAP_RXMASK]) {
+		u8 rxmask[IEEE80211_HT_MCS_MASK_LEN];
+
+		if (wdev)
+			return -EOPNOTSUPP;
+
+		memcpy(rxmask,
+		       nla_data(info->attrs[NL80211_ATTR_WIPHY_HTCAP_RXMASK]),
+		       IEEE80211_HT_MCS_MASK_LEN);
+
+		result = rdev_set_htcap_rxmask(rdev, rxmask);
+		if (result)
+			return result;
+	}
+
 	changed = 0;
 
 	if (info->attrs[NL80211_ATTR_WIPHY_RETRY_SHORT]) {
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 8ae0c04..488adb9 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -1071,4 +1071,15 @@ rdev_set_coalesce(struct cfg80211_registered_device *rdev,
 	trace_rdev_return_int(&rdev->wiphy, ret);
 	return ret;
 }
+
+static inline int
+rdev_set_htcap_rxmask(struct cfg80211_registered_device *rdev, uint8_t *rxmask)
+{
+	int ret;
+
+	trace_rdev_set_htcap_rxmask(&rdev->wiphy, rxmask);
+	ret = rdev->ops->set_htcap_rxmask(&rdev->wiphy, rxmask);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
 #endif /* __CFG80211_RDEV_OPS */
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 09b242b..d7c8c3c 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2120,6 +2120,21 @@ TRACE_EVENT(rdev_tdls_cancel_channel_switch,
 		  WIPHY_PR_ARG, NETDEV_PR_ARG, MAC_PR_ARG(addr))
 );
 
+TRACE_EVENT(rdev_set_htcap_rxmask,
+	TP_PROTO(struct wiphy *wiphy, uint8_t *rxmask),
+	TP_ARGS(wiphy, rxmask),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		__array(uint8_t, rxmask, IEEE80211_HT_MCS_MASK_LEN)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		memcpy(__entry->rxmask, rxmask, IEEE80211_HT_MCS_MASK_LEN);
+	),
+	TP_printk(WIPHY_PR_FMT ", %*ph",
+		  WIPHY_PR_ARG, IEEE80211_HT_MCS_MASK_LEN, &__entry->rxmask[0])
+);
+
 /*************************************************************
  *	     cfg80211 exported functions traces		     *
  *************************************************************/
-- 
1.9.1

Re: [RFC 0/2] mac80211: add support for ht_caps mcs rxmask override

[Johannes Berg]

[reducing CC list]

On Fri, 2016-02-05 at 16:41 +0100, Cedric DEBARGE wrote:
> This patchset allows the ht_caps mcs rxmask to be defined on the fly.
> It applies the given rxmask to all available bands.
> 
> This is actually limited to radio cards without internal rc.
> 

Curious. Ben Greear had suggested something that seems rather similar.
What are you working on that you need this?

I think my comments to him apply to this too - see the thread at
http://thread.gmane.org/gmane.linux.kernel.wireless.general/143789

johannes

RE: [RFC 0/2] mac80211: add support for ht_caps mcs rxmask override

[Cédric Debarge - ACKSYS]

> What are you working on that you need this?

We are working on critical industrial networks where a specific (generally high) bandwidth is required.
Supressing low MCSs (that are not able to handle the desired bandwidth) allows us to be sure that the wireless link can sustain the requested bandwidth.
If the radio conditions do not allow high enough MCSs, we prefer increase the AP density rather than not being able to communicate at the requested speed.
 
> I think my comments to him apply to this too - see the thread at
> http://thread.gmane.org/gmane.linux.kernel.wireless.general/143789

Thanks for the link, I didn't noticed Ben Grear's request.
According to the given patches, it seems the targeted goal is quite similar. So your comments also apply on my demand.

Anyway, thanks for your answer.

Cedric

Re: [RFC 0/2] mac80211: add support for ht_caps mcs rxmask override

[Johannes Berg]

On Fri, 2016-02-19 at 17:39 +0100, Cédric Debarge - ACKSYS wrote:
> > What are you working on that you need this?
> 
> We are working on critical industrial networks where a specific
> (generally high) bandwidth is required.
> Supressing low MCSs (that are not able to handle the desired
> bandwidth) allows us to be sure that the wireless link can sustain
> the requested bandwidth.
> If the radio conditions do not allow high enough MCSs, we prefer
> increase the AP density rather than not being able to communicate at
> the requested speed.

Interesting. So are you saying that you're trying to disable the
low(er) rates by not having the client systems advertise them, possibly
because you can't manipulate the transmitter to not use them?

But that seems a bit strange, since basic/mandatory rates always need
to be supported?

> > I think my comments to him apply to this too - see the thread at
> > http://thread.gmane.org/gmane.linux.kernel.wireless.general/143789
> 
> Thanks for the link, I didn't noticed Ben Grear's request.
> According to the given patches, it seems the targeted goal is quite
> similar. So your comments also apply on my demand.

It seems that your implementation is closer to what I was suggesting
though :)

johannes