[PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Jouni Malinen]

Add a new NL80211_CMD_SET_TX_BITRATE_MASK command and related
attributes to provide support for setting TX rate mask for rate
control. This uses the existing cfg80211 set_bitrate_mask operation
that was previously used only with WEXT compat code (SIOCSIWRATE). The
nl80211 command allows more generic configuration of allowed rates as
a mask instead of fixed/max rate.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>

---
 include/linux/nl80211.h |   44 +++++++++++++++++++
 include/net/cfg80211.h  |    4 -
 net/wireless/nl80211.c  |  111 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 157 insertions(+), 2 deletions(-)

--- wireless-testing.orig/include/linux/nl80211.h	2009-12-29 10:50:56.000000000 +0200
+++ wireless-testing/include/linux/nl80211.h	2009-12-29 10:56:42.000000000 +0200
@@ -295,6 +295,10 @@
  *	This command is also used as an event to notify when a requested
  *	remain-on-channel duration has expired.
  *
+ * @NL80211_CMD_SET_TX_BITRATE_MASK: Set the mask of rates to be used in TX
+ *	rate selection. %NL80211_ATTR_IFINDEX is used to specify the interface
+ *	and @NL80211_ATTR_TX_RATES the set of allowed rates.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -381,6 +385,8 @@ enum nl80211_commands {
 	NL80211_CMD_REMAIN_ON_CHANNEL,
 	NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL,
 
+	NL80211_CMD_SET_TX_BITRATE_MASK,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -638,6 +644,13 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_COOKIE: Generic 64-bit cookie to identify objects.
  *
+ * @NL80211_ATTR_TX_RATES: Nested set of attributes
+ *	(enum nl80211_tx_rate_attributes) describing TX rates per band. The
+ *	enum nl80211_band value is used as the index (nla_type() of the nested
+ *	data. If a band is not included, it will be configured to allow all
+ *	rates based on negotiated supported rates information. This attribute
+ *	is used with %NL80211_CMD_SET_TX_BITRATE_MASK.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -779,6 +792,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_COOKIE,
 
+	NL80211_ATTR_TX_RATES,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -1478,4 +1493,33 @@ enum nl80211_key_attributes {
 	NL80211_KEY_MAX = __NL80211_KEY_AFTER_LAST - 1
 };
 
+/**
+ * enum nl80211_tx_rate_attributes - TX rate set attributes
+ * @__NL80211_TXRATE_INVALID: invalid
+ * @NL80211_TXRATE_LEGACY: Legacy (non-MCS) rates allowed for TX rate selection
+ *	in an array of rates as defined in IEEE 802.11 7.3.2.2 (u8 values with
+ *	1 = 500 kbps) but without the IE length restriction (at most
+ *	%NL80211_MAX_SUPP_RATES in a single array).
+ * @__NL80211_TXRATE_AFTER_LAST: internal
+ * @NL80211_TXRATE_MAX: highest TX rate attribute
+ */
+enum nl80211_tx_rate_attributes {
+	__NL80211_TXRATE_INVALID,
+	NL80211_TXRATE_LEGACY,
+
+	/* keep last */
+	__NL80211_TXRATE_AFTER_LAST,
+	NL80211_TXRATE_MAX = __NL80211_TXRATE_AFTER_LAST - 1
+};
+
+/**
+ * enum nl80211_band - Frequency band
+ * @NL80211_BAND_2GHZ - 2.4 GHz ISM band
+ * @NL80211_BAND_5GHZ - around 5 GHz band (4.9 - 5.7 GHz)
+ */
+enum nl80211_band {
+	NL80211_BAND_2GHZ,
+	NL80211_BAND_5GHZ,
+};
+
 #endif /* __LINUX_NL80211_H */
--- wireless-testing.orig/net/wireless/nl80211.c	2009-12-29 10:50:57.000000000 +0200
+++ wireless-testing/net/wireless/nl80211.c	2009-12-29 10:57:37.000000000 +0200
@@ -143,6 +143,7 @@ static struct nla_policy nl80211_policy[
 				 .len = WLAN_PMKID_LEN },
 	[NL80211_ATTR_DURATION] = { .type = NLA_U32 },
 	[NL80211_ATTR_COOKIE] = { .type = NLA_U64 },
+	[NL80211_ATTR_TX_RATES] = { .type = NLA_NESTED },
 };
 
 /* policy for the attributes */
@@ -572,6 +573,7 @@ static int nl80211_send_wiphy(struct sk_
 	CMD(del_pmksa, DEL_PMKSA);
 	CMD(flush_pmksa, FLUSH_PMKSA);
 	CMD(remain_on_channel, REMAIN_ON_CHANNEL);
+	CMD(set_bitrate_mask, SET_TX_BITRATE_MASK);
 	if (dev->wiphy.flags & WIPHY_FLAG_NETNS_OK) {
 		i++;
 		NLA_PUT_U32(msg, i, NL80211_CMD_SET_WIPHY_NETNS);
@@ -4423,6 +4425,109 @@ static int nl80211_cancel_remain_on_chan
 	return err;
 }
 
+static u32 rateset_to_mask(struct ieee80211_supported_band *sband,
+			   u8 *rates, u8 rates_len)
+{
+	u8 i;
+	u32 mask = 0;
+
+	for (i = 0; i < rates_len; i++) {
+		int rate = (rates[i] & 0x7f) * 5;
+		int ridx;
+		for (ridx = 0; ridx < sband->n_bitrates; ridx++) {
+			struct ieee80211_rate *srate =
+				&sband->bitrates[ridx];
+			if (rate == srate->bitrate) {
+				mask |= 1 << ridx;
+				break;
+			}
+		}
+		if (ridx == sband->n_bitrates)
+			return 0; /* rate not found */
+	}
+
+	return mask;
+}
+
+static struct nla_policy
+nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] __read_mostly = {
+	[NL80211_TXRATE_LEGACY] = { .type = NLA_BINARY,
+				    .len = NL80211_MAX_SUPP_RATES },
+};
+
+static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
+				       struct genl_info *info)
+{
+	struct nlattr *tb[NL80211_TXRATE_MAX + 1];
+	struct cfg80211_registered_device *rdev;
+	struct cfg80211_bitrate_mask mask;
+	int err, rem, i;
+	struct net_device *dev;
+	struct nlattr *tx_rates;
+	struct ieee80211_supported_band *sband;
+
+	if (info->attrs[NL80211_ATTR_TX_RATES] == NULL)
+		return -EINVAL;
+
+	rtnl_lock();
+
+	err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
+	if (err)
+		goto unlock_rtnl;
+
+	if (!rdev->ops->set_bitrate_mask) {
+		err = -EOPNOTSUPP;
+		goto unlock;
+	}
+
+	memset(&mask, 0, sizeof(mask));
+	/* Default to all rates enabled */
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		sband = rdev->wiphy.bands[i];
+		mask.control[i].legacy =
+			sband ? (1 << sband->n_bitrates) - 1 : 0;
+	}
+
+	/*
+	 * The nested attribute uses enum nl80211_band as the index. This maps
+	 * directly to the enum ieee80211_band values used in cfg80211.
+	 */
+	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
+	{
+		enum ieee80211_band band = nla_type(tx_rates);
+		if (band < 0 || band >= IEEE80211_NUM_BANDS) {
+			err = -EINVAL;
+			goto unlock;
+		}
+		sband = rdev->wiphy.bands[band];
+		if (sband == NULL) {
+			err = -EINVAL;
+			goto unlock;
+		}
+		nla_parse(tb, NL80211_TXRATE_MAX, nla_data(tx_rates),
+			  nla_len(tx_rates), nl80211_txattr_policy);
+		if (tb[NL80211_TXRATE_LEGACY]) {
+			mask.control[band].legacy = rateset_to_mask(
+				sband,
+				nla_data(tb[NL80211_TXRATE_LEGACY]),
+				nla_len(tb[NL80211_TXRATE_LEGACY]));
+			if (mask.control[band].legacy == 0) {
+				err = -EINVAL;
+				goto unlock;
+			}
+		}
+	}
+
+	err = rdev->ops->set_bitrate_mask(&rdev->wiphy, dev, NULL, &mask);
+
+ unlock:
+	dev_put(dev);
+	cfg80211_unlock_rdev(rdev);
+ unlock_rtnl:
+	rtnl_unlock();
+	return err;
+}
+
 static struct genl_ops nl80211_ops[] = {
 	{
 		.cmd = NL80211_CMD_GET_WIPHY,
@@ -4697,6 +4802,12 @@ static struct genl_ops nl80211_ops[] = {
 		.policy = nl80211_policy,
 		.flags = GENL_ADMIN_PERM,
 	},
+	{
+		.cmd = NL80211_CMD_SET_TX_BITRATE_MASK,
+		.doit = nl80211_set_tx_bitrate_mask,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
--- wireless-testing.orig/include/net/cfg80211.h	2009-12-29 10:54:29.000000000 +0200
+++ wireless-testing/include/net/cfg80211.h	2009-12-29 10:55:52.000000000 +0200
@@ -39,8 +39,8 @@
  * @IEEE80211_BAND_5GHZ: around 5GHz band (4.9-5.7)
  */
 enum ieee80211_band {
-	IEEE80211_BAND_2GHZ,
-	IEEE80211_BAND_5GHZ,
+	IEEE80211_BAND_2GHZ = NL80211_BAND_2GHZ,
+	IEEE80211_BAND_5GHZ = NL80211_BAND_5GHZ,
 
 	/* keep last */
 	IEEE80211_NUM_BANDS

-- 

-- 
Jouni Malinen                                            PGP id EFC895FA

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Johannes Berg]

[-- Attachment #1: Type: text/plain, Size: 8636 bytes --]

On Tue, 2009-12-29 at 12:59 +0200, Jouni Malinen wrote:
> plain text document attachment (nl80211-rc-rate-mask.patch)
> Add a new NL80211_CMD_SET_TX_BITRATE_MASK command and related
> attributes to provide support for setting TX rate mask for rate
> control. This uses the existing cfg80211 set_bitrate_mask operation
> that was previously used only with WEXT compat code (SIOCSIWRATE). The
> nl80211 command allows more generic configuration of allowed rates as
> a mask instead of fixed/max rate.
> 
> Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>

Looks fine.

Acked-by: Johannes Berg <johannes@sipsolutions.net>

> ---
>  include/linux/nl80211.h |   44 +++++++++++++++++++
>  include/net/cfg80211.h  |    4 -
>  net/wireless/nl80211.c  |  111
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 157 insertions(+), 2 deletions(-)
> 
> --- wireless-testing.orig/include/linux/nl80211.h	2009-12-29
> 10:50:56.000000000 +0200
> +++ wireless-testing/include/linux/nl80211.h	2009-12-29
> 10:56:42.000000000 +0200
> @@ -295,6 +295,10 @@
>   *	This command is also used as an event to notify when a requested
>   *	remain-on-channel duration has expired.
>   *
> + * @NL80211_CMD_SET_TX_BITRATE_MASK: Set the mask of rates to be used
> in TX
> + *	rate selection. %NL80211_ATTR_IFINDEX is used to specify the
> interface
> + *	and @NL80211_ATTR_TX_RATES the set of allowed rates.
> + *
>   * @NL80211_CMD_MAX: highest used command number
>   * @__NL80211_CMD_AFTER_LAST: internal use
>   */
> @@ -381,6 +385,8 @@ enum nl80211_commands {
>  	NL80211_CMD_REMAIN_ON_CHANNEL,
>  	NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL,
>  
> +	NL80211_CMD_SET_TX_BITRATE_MASK,
> +
>  	/* add new commands above here */
>  
>  	/* used to define NL80211_CMD_MAX below */
> @@ -638,6 +644,13 @@ enum nl80211_commands {
>   *
>   * @NL80211_ATTR_COOKIE: Generic 64-bit cookie to identify objects.
>   *
> + * @NL80211_ATTR_TX_RATES: Nested set of attributes
> + *	(enum nl80211_tx_rate_attributes) describing TX rates per band.
> The
> + *	enum nl80211_band value is used as the index (nla_type() of the
> nested
> + *	data. If a band is not included, it will be configured to allow
> all
> + *	rates based on negotiated supported rates information. This
> attribute
> + *	is used with %NL80211_CMD_SET_TX_BITRATE_MASK.
> + *
>   * @NL80211_ATTR_MAX: highest attribute number currently defined
>   * @__NL80211_ATTR_AFTER_LAST: internal use
>   */
> @@ -779,6 +792,8 @@ enum nl80211_attrs {
>  
>  	NL80211_ATTR_COOKIE,
>  
> +	NL80211_ATTR_TX_RATES,
> +
>  	/* add attributes here, update the policy in nl80211.c */
>  
>  	__NL80211_ATTR_AFTER_LAST,
> @@ -1478,4 +1493,33 @@ enum nl80211_key_attributes {
>  	NL80211_KEY_MAX = __NL80211_KEY_AFTER_LAST - 1
>  };
>  
> +/**
> + * enum nl80211_tx_rate_attributes - TX rate set attributes
> + * @__NL80211_TXRATE_INVALID: invalid
> + * @NL80211_TXRATE_LEGACY: Legacy (non-MCS) rates allowed for TX rate
> selection
> + *	in an array of rates as defined in IEEE 802.11 7.3.2.2 (u8 values
> with
> + *	1 = 500 kbps) but without the IE length restriction (at most
> + *	%NL80211_MAX_SUPP_RATES in a single array).
> + * @__NL80211_TXRATE_AFTER_LAST: internal
> + * @NL80211_TXRATE_MAX: highest TX rate attribute
> + */
> +enum nl80211_tx_rate_attributes {
> +	__NL80211_TXRATE_INVALID,
> +	NL80211_TXRATE_LEGACY,
> +
> +	/* keep last */
> +	__NL80211_TXRATE_AFTER_LAST,
> +	NL80211_TXRATE_MAX = __NL80211_TXRATE_AFTER_LAST - 1
> +};
> +
> +/**
> + * enum nl80211_band - Frequency band
> + * @NL80211_BAND_2GHZ - 2.4 GHz ISM band
> + * @NL80211_BAND_5GHZ - around 5 GHz band (4.9 - 5.7 GHz)
> + */
> +enum nl80211_band {
> +	NL80211_BAND_2GHZ,
> +	NL80211_BAND_5GHZ,
> +};
> +
>  #endif /* __LINUX_NL80211_H */
> --- wireless-testing.orig/net/wireless/nl80211.c	2009-12-29
> 10:50:57.000000000 +0200
> +++ wireless-testing/net/wireless/nl80211.c	2009-12-29
> 10:57:37.000000000 +0200
> @@ -143,6 +143,7 @@ static struct nla_policy nl80211_policy[
>  				 .len = WLAN_PMKID_LEN },
>  	[NL80211_ATTR_DURATION] = { .type = NLA_U32 },
>  	[NL80211_ATTR_COOKIE] = { .type = NLA_U64 },
> +	[NL80211_ATTR_TX_RATES] = { .type = NLA_NESTED },
>  };
>  
>  /* policy for the attributes */
> @@ -572,6 +573,7 @@ static int nl80211_send_wiphy(struct sk_
>  	CMD(del_pmksa, DEL_PMKSA);
>  	CMD(flush_pmksa, FLUSH_PMKSA);
>  	CMD(remain_on_channel, REMAIN_ON_CHANNEL);
> +	CMD(set_bitrate_mask, SET_TX_BITRATE_MASK);
>  	if (dev->wiphy.flags & WIPHY_FLAG_NETNS_OK) {
>  		i++;
>  		NLA_PUT_U32(msg, i, NL80211_CMD_SET_WIPHY_NETNS);
> @@ -4423,6 +4425,109 @@ static int nl80211_cancel_remain_on_chan
>  	return err;
>  }
>  
> +static u32 rateset_to_mask(struct ieee80211_supported_band *sband,
> +			   u8 *rates, u8 rates_len)
> +{
> +	u8 i;
> +	u32 mask = 0;
> +
> +	for (i = 0; i < rates_len; i++) {
> +		int rate = (rates[i] & 0x7f) * 5;
> +		int ridx;
> +		for (ridx = 0; ridx < sband->n_bitrates; ridx++) {
> +			struct ieee80211_rate *srate =
> +				&sband->bitrates[ridx];
> +			if (rate == srate->bitrate) {
> +				mask |= 1 << ridx;
> +				break;
> +			}
> +		}
> +		if (ridx == sband->n_bitrates)
> +			return 0; /* rate not found */
> +	}
> +
> +	return mask;
> +}
> +
> +static struct nla_policy
> +nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] __read_mostly = {
> +	[NL80211_TXRATE_LEGACY] = { .type = NLA_BINARY,
> +				    .len = NL80211_MAX_SUPP_RATES },
> +};
> +
> +static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
> +				       struct genl_info *info)
> +{
> +	struct nlattr *tb[NL80211_TXRATE_MAX + 1];
> +	struct cfg80211_registered_device *rdev;
> +	struct cfg80211_bitrate_mask mask;
> +	int err, rem, i;
> +	struct net_device *dev;
> +	struct nlattr *tx_rates;
> +	struct ieee80211_supported_band *sband;
> +
> +	if (info->attrs[NL80211_ATTR_TX_RATES] == NULL)
> +		return -EINVAL;
> +
> +	rtnl_lock();
> +
> +	err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
> +	if (err)
> +		goto unlock_rtnl;
> +
> +	if (!rdev->ops->set_bitrate_mask) {
> +		err = -EOPNOTSUPP;
> +		goto unlock;
> +	}
> +
> +	memset(&mask, 0, sizeof(mask));
> +	/* Default to all rates enabled */
> +	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
> +		sband = rdev->wiphy.bands[i];
> +		mask.control[i].legacy =
> +			sband ? (1 << sband->n_bitrates) - 1 : 0;
> +	}
> +
> +	/*
> +	 * The nested attribute uses enum nl80211_band as the index. This
> maps
> +	 * directly to the enum ieee80211_band values used in cfg80211.
> +	 */
> +	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES],
> rem)
> +	{
> +		enum ieee80211_band band = nla_type(tx_rates);
> +		if (band < 0 || band >= IEEE80211_NUM_BANDS) {
> +			err = -EINVAL;
> +			goto unlock;
> +		}
> +		sband = rdev->wiphy.bands[band];
> +		if (sband == NULL) {
> +			err = -EINVAL;
> +			goto unlock;
> +		}
> +		nla_parse(tb, NL80211_TXRATE_MAX, nla_data(tx_rates),
> +			  nla_len(tx_rates), nl80211_txattr_policy);
> +		if (tb[NL80211_TXRATE_LEGACY]) {
> +			mask.control[band].legacy = rateset_to_mask(
> +				sband,
> +				nla_data(tb[NL80211_TXRATE_LEGACY]),
> +				nla_len(tb[NL80211_TXRATE_LEGACY]));
> +			if (mask.control[band].legacy == 0) {
> +				err = -EINVAL;
> +				goto unlock;
> +			}
> +		}
> +	}
> +
> +	err = rdev->ops->set_bitrate_mask(&rdev->wiphy, dev, NULL, &mask);
> +
> + unlock:
> +	dev_put(dev);
> +	cfg80211_unlock_rdev(rdev);
> + unlock_rtnl:
> +	rtnl_unlock();
> +	return err;
> +}
> +
>  static struct genl_ops nl80211_ops[] = {
>  	{
>  		.cmd = NL80211_CMD_GET_WIPHY,
> @@ -4697,6 +4802,12 @@ static struct genl_ops nl80211_ops[] = {
>  		.policy = nl80211_policy,
>  		.flags = GENL_ADMIN_PERM,
>  	},
> +	{
> +		.cmd = NL80211_CMD_SET_TX_BITRATE_MASK,
> +		.doit = nl80211_set_tx_bitrate_mask,
> +		.policy = nl80211_policy,
> +		.flags = GENL_ADMIN_PERM,
> +	},
>  };
>  
>  static struct genl_multicast_group nl80211_mlme_mcgrp = {
> --- wireless-testing.orig/include/net/cfg80211.h	2009-12-29
> 10:54:29.000000000 +0200
> +++ wireless-testing/include/net/cfg80211.h	2009-12-29
> 10:55:52.000000000 +0200
> @@ -39,8 +39,8 @@
>   * @IEEE80211_BAND_5GHZ: around 5GHz band (4.9-5.7)
>   */
>  enum ieee80211_band {
> -	IEEE80211_BAND_2GHZ,
> -	IEEE80211_BAND_5GHZ,
> +	IEEE80211_BAND_2GHZ = NL80211_BAND_2GHZ,
> +	IEEE80211_BAND_5GHZ = NL80211_BAND_5GHZ,
>  
>  	/* keep last */
>  	IEEE80211_NUM_BANDS
> 
> -- 
> 


[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 801 bytes --]

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Philip Prindeville]

  On 12/29/09 2:59 AM, Jouni Malinen wrote:

> Add a new NL80211_CMD_SET_TX_BITRATE_MASK command and related
> attributes to provide support for setting TX rate mask for rate
> control. This uses the existing cfg80211 set_bitrate_mask operation
> that was previously used only with WEXT compat code (SIOCSIWRATE). The
> nl80211 command allows more generic configuration of allowed rates as
> a mask instead of fixed/max rate.
>
> Signed-off-by: Jouni Malinen<jouni.malinen@atheros.com>
>
> ---
>   include/linux/nl80211.h |   44 +++++++++++++++++++
>   include/net/cfg80211.h  |    4 -
>   net/wireless/nl80211.c  |  111 ++++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 157 insertions(+), 2 deletions(-)
>
> --- wireless-testing.orig/include/linux/nl80211.h	2009-12-29 10:50:56.000000000 +0200
> +++ wireless-testing/include/linux/nl80211.h	2009-12-29 10:56:42.000000000 +0200
> @@ -295,6 +295,10 @@
>    *	This command is also used as an event to notify when a requested
>    *	remain-on-channel duration has expired.
>    *
> + * @NL80211_CMD_SET_TX_BITRATE_MASK: Set the mask of rates to be used in TX
> + *	rate selection. %NL80211_ATTR_IFINDEX is used to specify the interface
> + *	and @NL80211_ATTR_TX_RATES the set of allowed rates.
> + *
>    * @NL80211_CMD_MAX: highest used command number
>    * @__NL80211_CMD_AFTER_LAST: internal use
>    */
> @@ -381,6 +385,8 @@ enum nl80211_commands {
>   	NL80211_CMD_REMAIN_ON_CHANNEL,
>   	NL80211_CMD_CANCEL_REMAIN_ON_CHANNEL,
>
> +	NL80211_CMD_SET_TX_BITRATE_MASK,
> +
>   	/* add new commands above here */
>
>   	/* used to define NL80211_CMD_MAX below */
> @@ -638,6 +644,13 @@ enum nl80211_commands {
>    *
>    * @NL80211_ATTR_COOKIE: Generic 64-bit cookie to identify objects.
>    *
> + * @NL80211_ATTR_TX_RATES: Nested set of attributes
> + *	(enum nl80211_tx_rate_attributes) describing TX rates per band. The
> + *	enum nl80211_band value is used as the index (nla_type() of the nested
> + *	data. If a band is not included, it will be configured to allow all
> + *	rates based on negotiated supported rates information. This attribute
> + *	is used with %NL80211_CMD_SET_TX_BITRATE_MASK.
> + *
>    * @NL80211_ATTR_MAX: highest attribute number currently defined
>    * @__NL80211_ATTR_AFTER_LAST: internal use
>    */
> @@ -779,6 +792,8 @@ enum nl80211_attrs {
>
>   	NL80211_ATTR_COOKIE,
>
> +	NL80211_ATTR_TX_RATES,
> +
>   	/* add attributes here, update the policy in nl80211.c */
>
>   	__NL80211_ATTR_AFTER_LAST,
> @@ -1478,4 +1493,33 @@ enum nl80211_key_attributes {
>   	NL80211_KEY_MAX = __NL80211_KEY_AFTER_LAST - 1
>   };
>
> +/**
> + * enum nl80211_tx_rate_attributes - TX rate set attributes
> + * @__NL80211_TXRATE_INVALID: invalid
> + * @NL80211_TXRATE_LEGACY: Legacy (non-MCS) rates allowed for TX rate selection
> + *	in an array of rates as defined in IEEE 802.11 7.3.2.2 (u8 values with
> + *	1 = 500 kbps) but without the IE length restriction (at most
> + *	%NL80211_MAX_SUPP_RATES in a single array).
> + * @__NL80211_TXRATE_AFTER_LAST: internal
> + * @NL80211_TXRATE_MAX: highest TX rate attribute
> + */
> +enum nl80211_tx_rate_attributes {
> +	__NL80211_TXRATE_INVALID,
> +	NL80211_TXRATE_LEGACY,
> +
> +	/* keep last */
> +	__NL80211_TXRATE_AFTER_LAST,
> +	NL80211_TXRATE_MAX = __NL80211_TXRATE_AFTER_LAST - 1
> +};
> +
> +/**
> + * enum nl80211_band - Frequency band
> + * @NL80211_BAND_2GHZ - 2.4 GHz ISM band
> + * @NL80211_BAND_5GHZ - around 5 GHz band (4.9 - 5.7 GHz)
> + */
> +enum nl80211_band {
> +	NL80211_BAND_2GHZ,
> +	NL80211_BAND_5GHZ,
> +};
> +
>   #endif /* __LINUX_NL80211_H */
> --- wireless-testing.orig/net/wireless/nl80211.c	2009-12-29 10:50:57.000000000 +0200
> +++ wireless-testing/net/wireless/nl80211.c	2009-12-29 10:57:37.000000000 +0200
> @@ -143,6 +143,7 @@ static struct nla_policy nl80211_policy[
>   				 .len = WLAN_PMKID_LEN },
>   	[NL80211_ATTR_DURATION] = { .type = NLA_U32 },
>   	[NL80211_ATTR_COOKIE] = { .type = NLA_U64 },
> +	[NL80211_ATTR_TX_RATES] = { .type = NLA_NESTED },
>   };
>
>   /* policy for the attributes */
> @@ -572,6 +573,7 @@ static int nl80211_send_wiphy(struct sk_
>   	CMD(del_pmksa, DEL_PMKSA);
>   	CMD(flush_pmksa, FLUSH_PMKSA);
>   	CMD(remain_on_channel, REMAIN_ON_CHANNEL);
> +	CMD(set_bitrate_mask, SET_TX_BITRATE_MASK);
>   	if (dev->wiphy.flags&  WIPHY_FLAG_NETNS_OK) {
>   		i++;
>   		NLA_PUT_U32(msg, i, NL80211_CMD_SET_WIPHY_NETNS);
> @@ -4423,6 +4425,109 @@ static int nl80211_cancel_remain_on_chan
>   	return err;
>   }
>
> +static u32 rateset_to_mask(struct ieee80211_supported_band *sband,
> +			   u8 *rates, u8 rates_len)
> +{
> +	u8 i;
> +	u32 mask = 0;
> +
> +	for (i = 0; i<  rates_len; i++) {
> +		int rate = (rates[i]&  0x7f) * 5;
> +		int ridx;
> +		for (ridx = 0; ridx<  sband->n_bitrates; ridx++) {
> +			struct ieee80211_rate *srate =
> +				&sband->bitrates[ridx];
> +			if (rate == srate->bitrate) {
> +				mask |= 1<<  ridx;
> +				break;
> +			}
> +		}
> +		if (ridx == sband->n_bitrates)
> +			return 0; /* rate not found */
> +	}
> +
> +	return mask;
> +}
> +
> +static struct nla_policy
> +nl80211_txattr_policy[NL80211_TXRATE_MAX + 1] __read_mostly = {
> +	[NL80211_TXRATE_LEGACY] = { .type = NLA_BINARY,
> +				    .len = NL80211_MAX_SUPP_RATES },
> +};
> +
> +static int nl80211_set_tx_bitrate_mask(struct sk_buff *skb,
> +				       struct genl_info *info)
> +{
> +	struct nlattr *tb[NL80211_TXRATE_MAX + 1];
> +	struct cfg80211_registered_device *rdev;
> +	struct cfg80211_bitrate_mask mask;
> +	int err, rem, i;
> +	struct net_device *dev;
> +	struct nlattr *tx_rates;
> +	struct ieee80211_supported_band *sband;
> +
> +	if (info->attrs[NL80211_ATTR_TX_RATES] == NULL)
> +		return -EINVAL;
> +
> +	rtnl_lock();
> +
> +	err = get_rdev_dev_by_info_ifindex(info,&rdev,&dev);
> +	if (err)
> +		goto unlock_rtnl;
> +
> +	if (!rdev->ops->set_bitrate_mask) {
> +		err = -EOPNOTSUPP;
> +		goto unlock;
> +	}
> +
> +	memset(&mask, 0, sizeof(mask));
> +	/* Default to all rates enabled */
> +	for (i = 0; i<  IEEE80211_NUM_BANDS; i++) {
> +		sband = rdev->wiphy.bands[i];
> +		mask.control[i].legacy =
> +			sband ? (1<<  sband->n_bitrates) - 1 : 0;
> +	}
> +
> +	/*
> +	 * The nested attribute uses enum nl80211_band as the index. This maps
> +	 * directly to the enum ieee80211_band values used in cfg80211.
> +	 */
> +	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
> +	{
> +		enum ieee80211_band band = nla_type(tx_rates);

Can this even work?  The first entry in nl80211_band is NL80211_BAND_2GHZ, i.e. zero.

Yet looking at libnl-1.1/lib/attr.c there's:

int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
               struct nla_policy *policy)
{
...
         nla_for_each_attr(nla, head, len, rem) {
                 int type = nla_type(nla);

                 if (type == 0) {
                         fprintf(stderr, "Illegal nla->nla_type == 0\n");
                         continue;
                 }

so any time nla->nla_type is set to NL80211_BAND_2GHZ, isn't this going to be problematic?

Or am I misreading this code?

-Philip


> +		if (band<  0 || band>= IEEE80211_NUM_BANDS) {
> +			err = -EINVAL;
> +			goto unlock;
> +		}
> +		sband = rdev->wiphy.bands[band];
> +		if (sband == NULL) {
> +			err = -EINVAL;
> +			goto unlock;
> +		}
> +		nla_parse(tb, NL80211_TXRATE_MAX, nla_data(tx_rates),
> +			  nla_len(tx_rates), nl80211_txattr_policy);
> +		if (tb[NL80211_TXRATE_LEGACY]) {
> +			mask.control[band].legacy = rateset_to_mask(
> +				sband,
> +				nla_data(tb[NL80211_TXRATE_LEGACY]),
> +				nla_len(tb[NL80211_TXRATE_LEGACY]));
> +			if (mask.control[band].legacy == 0) {
> +				err = -EINVAL;
> +				goto unlock;
> +			}
> +		}
> +	}
> +
> +	err = rdev->ops->set_bitrate_mask(&rdev->wiphy, dev, NULL,&mask);
> +
> + unlock:
> +	dev_put(dev);
> +	cfg80211_unlock_rdev(rdev);
> + unlock_rtnl:
> +	rtnl_unlock();
> +	return err;
> +}
> +
>   static struct genl_ops nl80211_ops[] = {
>   	{
>   		.cmd = NL80211_CMD_GET_WIPHY,
> @@ -4697,6 +4802,12 @@ static struct genl_ops nl80211_ops[] = {
>   		.policy = nl80211_policy,
>   		.flags = GENL_ADMIN_PERM,
>   	},
> +	{
> +		.cmd = NL80211_CMD_SET_TX_BITRATE_MASK,
> +		.doit = nl80211_set_tx_bitrate_mask,
> +		.policy = nl80211_policy,
> +		.flags = GENL_ADMIN_PERM,
> +	},
>   };
>
>   static struct genl_multicast_group nl80211_mlme_mcgrp = {
> --- wireless-testing.orig/include/net/cfg80211.h	2009-12-29 10:54:29.000000000 +0200
> +++ wireless-testing/include/net/cfg80211.h	2009-12-29 10:55:52.000000000 +0200
> @@ -39,8 +39,8 @@
>    * @IEEE80211_BAND_5GHZ: around 5GHz band (4.9-5.7)
>    */
>   enum ieee80211_band {
> -	IEEE80211_BAND_2GHZ,
> -	IEEE80211_BAND_5GHZ,
> +	IEEE80211_BAND_2GHZ = NL80211_BAND_2GHZ,
> +	IEEE80211_BAND_5GHZ = NL80211_BAND_5GHZ,
>
>   	/* keep last */
>   	IEEE80211_NUM_BANDS
>

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Johannes Berg]

On Thu, 2010-08-19 at 14:26 -0700, Philip Prindeville wrote:

> > +	/*
> > +	 * The nested attribute uses enum nl80211_band as the index. This maps
> > +	 * directly to the enum ieee80211_band values used in cfg80211.
> > +	 */
> > +	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
> > +	{
> > +		enum ieee80211_band band = nla_type(tx_rates);
> 
> Can this even work?  The first entry in nl80211_band is NL80211_BAND_2GHZ, i.e. zero.
> 
> Yet looking at libnl-1.1/lib/attr.c there's:
> 
> int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
>                struct nla_policy *policy)
> {
> ...
>          nla_for_each_attr(nla, head, len, rem) {
>                  int type = nla_type(nla);
> 
>                  if (type == 0) {

Well, notice how you're quoting code that does the same thing
(for_each_attr), but the latter code does the extra non-zero check,
which we don't.

We don't use nla_parse for this, we have to use
nla_parse_nested/for_each_attr. Yeah, it's a little quirky, but still
works fine.

johannes

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Philip Prindeville]

  On 8/20/10 2:20 AM, Johannes Berg wrote:
> On Thu, 2010-08-19 at 14:26 -0700, Philip Prindeville wrote:
>
>>> +	/*
>>> +	 * The nested attribute uses enum nl80211_band as the index. This maps
>>> +	 * directly to the enum ieee80211_band values used in cfg80211.
>>> +	 */
>>> +	nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
>>> +	{
>>> +		enum ieee80211_band band = nla_type(tx_rates);
>> Can this even work?  The first entry in nl80211_band is NL80211_BAND_2GHZ, i.e. zero.
>>
>> Yet looking at libnl-1.1/lib/attr.c there's:
>>
>> int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
>>                 struct nla_policy *policy)
>> {
>> ...
>>           nla_for_each_attr(nla, head, len, rem) {
>>                   int type = nla_type(nla);
>>
>>                   if (type == 0) {
> Well, notice how you're quoting code that does the same thing
> (for_each_attr), but the latter code does the extra non-zero check,
> which we don't.
>
> We don't use nla_parse for this, we have to use
> nla_parse_nested/for_each_attr. Yeah, it's a little quirky, but still
> works fine.
>
> johannes
>

Well, I grepped through all the relevant source (i.e. libnl and iw) and the only place that the string "Illegal nla->nla_type == 0" gets printed was there, and I'm definitely seeing it.

So while the condition might be set in the driver, it's detected in "iw" here.

That was my point.

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Philip Prindeville]

  On 8/20/10 9:33 AM, Philip Prindeville wrote:
>  On 8/20/10 2:20 AM, Johannes Berg wrote:
>> On Thu, 2010-08-19 at 14:26 -0700, Philip Prindeville wrote:
>>
>>>> +    /*
>>>> +     * The nested attribute uses enum nl80211_band as the index. This maps
>>>> +     * directly to the enum ieee80211_band values used in cfg80211.
>>>> +     */
>>>> +    nla_for_each_nested(tx_rates, info->attrs[NL80211_ATTR_TX_RATES], rem)
>>>> +    {
>>>> +        enum ieee80211_band band = nla_type(tx_rates);
>>> Can this even work?  The first entry in nl80211_band is NL80211_BAND_2GHZ, i.e. zero.
>>>
>>> Yet looking at libnl-1.1/lib/attr.c there's:
>>>
>>> int nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
>>>                 struct nla_policy *policy)
>>> {
>>> ...
>>>           nla_for_each_attr(nla, head, len, rem) {
>>>                   int type = nla_type(nla);
>>>
>>>                   if (type == 0) {
>> Well, notice how you're quoting code that does the same thing
>> (for_each_attr), but the latter code does the extra non-zero check,
>> which we don't.
>>
>> We don't use nla_parse for this, we have to use
>> nla_parse_nested/for_each_attr. Yeah, it's a little quirky, but still
>> works fine.
>>
>> johannes
>>
>
> Well, I grepped through all the relevant source (i.e. libnl and iw) and the only place that the string "Illegal nla->nla_type == 0" gets printed was there, and I'm definitely seeing it.
>
> So while the condition might be set in the driver, it's detected in "iw" here.
>
> That was my point.


What I'm trying to say is that even though the driver handles the condition of nla_type == 0 when it generates the message, the condition isn't handled correct when the message finally gets passed up into user-space, because the above sequence in the netlink library gets hit both for "iw" and "hostapd".

So it's not enough to handle it correctly in the driver: it needs to be handled in libnl as well.

There are 3 potential solutions:

(1) go with a 1-based enum for the band, instead of 0-based;
(2) remove the test for nla_type == 0 in nla_parse() in libnl;
(3) use a way to convey the band that doesn't involve overloading nla_type;

What's the correct fix?

Thanks,

-Philip

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Johannes Berg]

On Fri, 2010-08-20 at 15:54 -0700, Philip Prindeville wrote:

> What I'm trying to say is that even though the driver handles the
> condition of nla_type == 0 when it generates the message, the
> condition isn't handled correct when the message finally gets passed
> up into user-space, because the above sequence in the netlink library
> gets hit both for "iw" and "hostapd".
> 
> So it's not enough to handle it correctly in the driver: it needs to
> be handled in libnl as well.
> 
> There are 3 potential solutions:
> 
> (1) go with a 1-based enum for the band, instead of 0-based;
> (2) remove the test for nla_type == 0 in nla_parse() in libnl;
> (3) use a way to convey the band that doesn't involve overloading
> nla_type;
> 
> What's the correct fix?

You managed to totally throw me off course ... The problem is completely
unrelated to this, see the patch I just sent :-)

johannes

Re: [PATCH 3/3] nl80211: New command for setting TX rate mask for rate control

[Philip Prindeville]

  On 8/24/10 3:16 AM, Johannes Berg wrote:
> On Fri, 2010-08-20 at 15:54 -0700, Philip Prindeville wrote:
>
>> What I'm trying to say is that even though the driver handles the
>> condition of nla_type == 0 when it generates the message, the
>> condition isn't handled correct when the message finally gets passed
>> up into user-space, because the above sequence in the netlink library
>> gets hit both for "iw" and "hostapd".
>>
>> So it's not enough to handle it correctly in the driver: it needs to
>> be handled in libnl as well.
>>
>> There are 3 potential solutions:
>>
>> (1) go with a 1-based enum for the band, instead of 0-based;
>> (2) remove the test for nla_type == 0 in nla_parse() in libnl;
>> (3) use a way to convey the band that doesn't involve overloading
>> nla_type;
>>
>> What's the correct fix?
> You managed to totally throw me off course ... The problem is completely
> unrelated to this, see the patch I just sent :-)
>
> johannes
>

Confirmed your fix.  http://pastebin.ca/1924624

Thanks!