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nl80211: support scan frequencies in KHz

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If the driver advertises NL80211_EXT_FEATURE_SCAN_FREQ_KHZ
userspace can omit NL80211_ATTR_SCAN_FREQUENCIES in favor
of an NL80211_ATTR_SCAN_FREQ_KHZ. To get scan results in
KHz userspace must also set the
NL80211_SCAN_FLAG_FREQ_KHZ.

This lets nl80211 remain compatible with older userspaces
while not requring and sending redundant (and potentially
incorrect) scan frequency sets.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200430172554.18383-4-thomas@adapt-ip.com
[use just nla_nest_start() (not _noflag) for NL80211_ATTR_SCAN_FREQ_KHZ]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Thomas Pedersen 2020-04-30 10:25:52 -07:00 committed by Johannes Berg
parent 942ba88ba9
commit 2032f3b2f9
3 changed files with 53 additions and 13 deletions
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13
include/uapi/linux/nl80211.h
View file

@ -2492,7 +2492,7 @@ enum nl80211_commands {
* an %NL80211_ATTR_WIPHY_FREQ_OFFSET.
* @NL80211_ATTR_CENTER_FREQ1_OFFSET: Center frequency offset in KHz for the
* first channel segment specified in %NL80211_ATTR_CENTER_FREQ1.
*
* @NL80211_ATTR_SCAN_FREQ_KHZ: nested attribute with KHz frequencies
*
* @NUM_NL80211_ATTR: total number of nl80211_attrs available
* @NL80211_ATTR_MAX: highest attribute number currently defined
@ -2972,6 +2972,7 @@ enum nl80211_attrs {
NL80211_ATTR_RECEIVE_MULTICAST,
NL80211_ATTR_WIPHY_FREQ_OFFSET,
NL80211_ATTR_CENTER_FREQ1_OFFSET,
NL80211_ATTR_SCAN_FREQ_KHZ,
/* add attributes here, update the policy in nl80211.c */
@ -5723,6 +5724,11 @@ enum nl80211_feature_flags {
* @NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS: management frame registrations
* are possible for multicast frames and those will be reported properly.
*
* @NL80211_EXT_FEATURE_SCAN_FREQ_KHZ: This driver supports receiving and
* reporting scan request with %NL80211_ATTR_SCAN_FREQ_KHZ. In order to
* report %NL80211_ATTR_SCAN_FREQ_KHZ, %NL80211_SCAN_FLAG_FREQ_KHZ must be
* included in the scan request.
*
* @NUM_NL80211_EXT_FEATURES: number of extended features.
* @MAX_NL80211_EXT_FEATURES: highest extended feature index.
*/
@ -5776,6 +5782,7 @@ enum nl80211_ext_feature_index {
NL80211_EXT_FEATURE_DEL_IBSS_STA,
NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS,
NL80211_EXT_FEATURE_BEACON_PROTECTION_CLIENT,
NL80211_EXT_FEATURE_SCAN_FREQ_KHZ,
/* add new features before the definition below */
NUM_NL80211_EXT_FEATURES,
@ -5887,6 +5894,9 @@ enum nl80211_timeout_reason {
* @NL80211_SCAN_FLAG_MIN_PREQ_CONTENT: minimize probe request content to
* only have supported rates and no additional capabilities (unless
* added by userspace explicitly.)
* @NL80211_SCAN_FLAG_FREQ_KHZ: report scan results with
* %NL80211_ATTR_SCAN_FREQ_KHZ. This also means
* %NL80211_ATTR_SCAN_FREQUENCIES will not be included.
*/
enum nl80211_scan_flags {
NL80211_SCAN_FLAG_LOW_PRIORITY = 1<<0,
@ -5902,6 +5912,7 @@ enum nl80211_scan_flags {
NL80211_SCAN_FLAG_HIGH_ACCURACY = 1<<10,
NL80211_SCAN_FLAG_RANDOM_SN = 1<<11,
NL80211_SCAN_FLAG_MIN_PREQ_CONTENT = 1<<12,
NL80211_SCAN_FLAG_FREQ_KHZ = 1<<13,
};
/**

2
net/mac80211/main.c
View file

@ -596,6 +596,8 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211);
wiphy_ext_feature_set(wiphy,
NL80211_EXT_FEATURE_CONTROL_PORT_NO_PREAUTH);
wiphy_ext_feature_set(wiphy,
NL80211_EXT_FEATURE_SCAN_FREQ_KHZ);
if (!ops->hw_scan) {
wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN |

51
net/wireless/nl80211.c
View file

@ -640,6 +640,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
[NL80211_ATTR_PMK_REAUTH_THRESHOLD] = NLA_POLICY_RANGE(NLA_U8, 1, 100),
[NL80211_ATTR_RECEIVE_MULTICAST] = { .type = NLA_FLAG },
[NL80211_ATTR_WIPHY_FREQ_OFFSET] = NLA_POLICY_RANGE(NLA_U32, 0, 999),
[NL80211_ATTR_SCAN_FREQ_KHZ] = { .type = NLA_NESTED },
};
/* policy for the key attributes */
@ -7719,6 +7720,8 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
struct cfg80211_registered_device *rdev = info->user_ptr[0];
struct wireless_dev *wdev = info->user_ptr[1];
struct cfg80211_scan_request *request;
struct nlattr *scan_freqs = NULL;
bool scan_freqs_khz = false;
struct nlattr *attr;
struct wiphy *wiphy;
int err, tmp, n_ssids = 0, n_channels, i;
@ -7737,9 +7740,17 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
goto unlock;
}
if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
n_channels = validate_scan_freqs(
info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]);
if (info->attrs[NL80211_ATTR_SCAN_FREQ_KHZ]) {
if (!wiphy_ext_feature_isset(wiphy,
NL80211_EXT_FEATURE_SCAN_FREQ_KHZ))
return -EOPNOTSUPP;
scan_freqs = info->attrs[NL80211_ATTR_SCAN_FREQ_KHZ];
scan_freqs_khz = true;
} else if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES])
scan_freqs = info->attrs[NL80211_ATTR_SCAN_FREQUENCIES];
if (scan_freqs) {
n_channels = validate_scan_freqs(scan_freqs);
if (!n_channels) {
err = -EINVAL;
goto unlock;
@ -7787,13 +7798,16 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
}
i = 0;
if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
if (scan_freqs) {
/* user specified, bail out if channel not found */
nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_FREQUENCIES], tmp) {
nla_for_each_nested(attr, scan_freqs, tmp) {
struct ieee80211_channel *chan;
int freq = nla_get_u32(attr);
chan = ieee80211_get_channel(wiphy, nla_get_u32(attr));
if (!scan_freqs_khz)
freq = MHZ_TO_KHZ(freq);
chan = ieee80211_get_channel_khz(wiphy, freq);
if (!chan) {
err = -EINVAL;
goto out_free;
@ -15231,14 +15245,27 @@ static int nl80211_add_scan_req(struct sk_buff *msg,
}
nla_nest_end(msg, nest);
nest = nla_nest_start_noflag(msg, NL80211_ATTR_SCAN_FREQUENCIES);
if (!nest)
goto nla_put_failure;
for (i = 0; i < req->n_channels; i++) {
if (nla_put_u32(msg, i, req->channels[i]->center_freq))
if (req->flags & NL80211_SCAN_FLAG_FREQ_KHZ) {
nest = nla_nest_start(msg, NL80211_ATTR_SCAN_FREQ_KHZ);
if (!nest)
goto nla_put_failure;
for (i = 0; i < req->n_channels; i++) {
if (nla_put_u32(msg, i,
ieee80211_channel_to_khz(req->channels[i])))
goto nla_put_failure;
}
nla_nest_end(msg, nest);
} else {
nest = nla_nest_start_noflag(msg,
NL80211_ATTR_SCAN_FREQUENCIES);
if (!nest)
goto nla_put_failure;
for (i = 0; i < req->n_channels; i++) {
if (nla_put_u32(msg, i, req->channels[i]->center_freq))
goto nla_put_failure;
}
nla_nest_end(msg, nest);
}
nla_nest_end(msg, nest);
if (req->ie &&
nla_put(msg, NL80211_ATTR_IE, req->ie_len, req->ie))