Commit 2032f3b2 authored by Thomas Pedersen's avatar Thomas Pedersen Committed by Johannes Berg
Browse files

nl80211: support scan frequencies in KHz 



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: default avatarThomas 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: default avatarJohannes Berg <johannes.berg@intel.com>
parent 942ba88b

include/uapi/linux/nl80211.h

+12 −1
Original line number Diff line number Diff line
@@ -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,

};



/**

net/mac80211/main.c

+2 −0
Original line number Diff line number Diff line
@@ -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 |

net/wireless/nl80211.c

+39 −12
Original line number Diff line number Diff line
@@ -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;
@@ -15231,7 +15245,19 @@ 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 (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++) {
@@ -15239,6 +15265,7 @@ static int nl80211_add_scan_req(struct sk_buff *msg, 
				goto nla_put_failure;

		}

		nla_nest_end(msg, nest);

	}



	if (req->ie &&

	    nla_put(msg, NL80211_ATTR_IE, req->ie_len, req->ie))

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