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nl80211: New command for setting TX rate mask for rate control
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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>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Jouni Malinen authored and John W. Linville committed Jan 12, 2010
1 parent 37eb0b1 commit 13ae75b
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Showing 3 changed files with 157 additions and 2 deletions.
44 changes: 44 additions & 0 deletions include/linux/nl80211.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
*/
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -640,6 +646,13 @@ 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
*/
Expand Down Expand Up @@ -783,6 +796,8 @@ enum nl80211_attrs {

NL80211_ATTR_WIPHY_COVERAGE_CLASS,

NL80211_ATTR_TX_RATES,

/* add attributes here, update the policy in nl80211.c */

__NL80211_ATTR_AFTER_LAST,
Expand Down Expand Up @@ -1482,4 +1497,33 @@ 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 */
4 changes: 2 additions & 2 deletions include/net/cfg80211.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
111 changes: 111 additions & 0 deletions net/wireless/nl80211.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,7 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
.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 */
Expand Down Expand Up @@ -575,6 +576,7 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
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);
Expand Down Expand Up @@ -4438,6 +4440,109 @@ static int nl80211_cancel_remain_on_channel(struct sk_buff *skb,
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,
Expand Down Expand Up @@ -4712,6 +4817,12 @@ 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 = {
Expand Down

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