Commit a1f1c21c authored by Luciano Coelho's avatar Luciano Coelho Committed by John W. Linville
Browse files

nl80211/cfg80211: add match filtering for sched_scan 



Introduce filtering for scheduled scans to reduce the number of
unnecessary results (which cause useless wake-ups).

Add a new nested attribute where sets of parameters to be matched can
be passed when starting a scheduled scan.  Only scan results that
match any of the sets will be returned.

At this point, the set consists of a single parameter, an SSID.  This
can be easily extended in the future to support more complex matches.

Signed-off-by: default avatarLuciano Coelho <coelho@ti.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent cedb5412

include/linux/nl80211.h

+43 −0
Original line number Diff line number Diff line
@@ -769,6 +769,8 @@ enum nl80211_commands { 
 *	that can be added to a scan request

 * @NL80211_ATTR_MAX_SCHED_SCAN_IE_LEN: maximum length of information

 *	elements that can be added to a scheduled scan request

 * @NL80211_ATTR_MAX_MATCH_SETS: maximum number of sets that can be

 *	used with @NL80211_ATTR_SCHED_SCAN_MATCH, a wiphy attribute.

 *

 * @NL80211_ATTR_SCAN_FREQUENCIES: nested attribute with frequencies (in MHz)

 * @NL80211_ATTR_SCAN_SSIDS: nested attribute with SSIDs, leave out for passive
@@ -1011,6 +1013,24 @@ enum nl80211_commands { 


 * @NL80211_ATTR_SCHED_SCAN_INTERVAL: Interval between scheduled scan

 *	cycles, in msecs.



 * @NL80211_ATTR_SCHED_SCAN_MATCH: Nested attribute with one or more

 *	sets of attributes to match during scheduled scans.  Only BSSs

 *	that match any of the sets will be reported.  These are

 *	pass-thru filter rules.

 *	For a match to succeed, the BSS must match all attributes of a

 *	set.  Since not every hardware supports matching all types of

 *	attributes, there is no guarantee that the reported BSSs are

 *	fully complying with the match sets and userspace needs to be

 *	able to ignore them by itself.

 *	Thus, the implementation is somewhat hardware-dependent, but

 *	this is only an optimization and the userspace application

 *	needs to handle all the non-filtered results anyway.

 *	If the match attributes don't make sense when combined with

 *	the values passed in @NL80211_ATTR_SCAN_SSIDS (eg. if an SSID

 *	is included in the probe request, but the match attributes

 *	will never let it go through), -EINVAL may be returned.

 *	If ommited, no filtering is done.

 *

 * @NL80211_ATTR_INTERFACE_COMBINATIONS: Nested attribute listing the supported

 *	interface combinations. In each nested item, it contains attributes
@@ -1265,6 +1285,9 @@ enum nl80211_attrs { 


	NL80211_ATTR_ROAM_SUPPORT,



	NL80211_ATTR_SCHED_SCAN_MATCH,

	NL80211_ATTR_MAX_MATCH_SETS,



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



	__NL80211_ATTR_AFTER_LAST,
@@ -1723,6 +1746,26 @@ enum nl80211_reg_rule_attr { 
	NL80211_REG_RULE_ATTR_MAX = __NL80211_REG_RULE_ATTR_AFTER_LAST - 1

};



/**

 * enum nl80211_sched_scan_match_attr - scheduled scan match attributes

 * @__NL80211_SCHED_SCAN_MATCH_ATTR_INVALID: attribute number 0 is reserved

 * @NL80211_SCHED_SCAN_MATCH_ATTR_SSID: SSID to be used for matching,

 * only report BSS with matching SSID.

 * @NL80211_SCHED_SCAN_MATCH_ATTR_MAX: highest scheduled scan filter

 *	attribute number currently defined

 * @__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST: internal use

 */

enum nl80211_sched_scan_match_attr {

	__NL80211_SCHED_SCAN_MATCH_ATTR_INVALID,



	NL80211_ATTR_SCHED_SCAN_MATCH_SSID,



	/* keep last */

	__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST,

	NL80211_SCHED_SCAN_MATCH_ATTR_MAX =

		__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST - 1

};



/**

 * enum nl80211_reg_rule_flags - regulatory rule flags

 *

include/net/cfg80211.h

+20 −0
Original line number Diff line number Diff line
@@ -875,6 +875,15 @@ struct cfg80211_scan_request { 
	struct ieee80211_channel *channels[0];

};



/**

 * struct cfg80211_match_set - sets of attributes to match

 *

 * @ssid: SSID to be matched

 */

struct cfg80211_match_set {

	struct cfg80211_ssid ssid;

};



/**

 * struct cfg80211_sched_scan_request - scheduled scan request description

 *
@@ -884,6 +893,11 @@ struct cfg80211_scan_request { 
 * @interval: interval between each scheduled scan cycle

 * @ie: optional information element(s) to add into Probe Request or %NULL

 * @ie_len: length of ie in octets

 * @match_sets: sets of parameters to be matched for a scan result

 * 	entry to be considered valid and to be passed to the host

 * 	(others are filtered out).

 *	If ommited, all results are passed.

 * @n_match_sets: number of match sets

 * @wiphy: the wiphy this was for

 * @dev: the interface

 * @channels: channels to scan
@@ -895,6 +909,8 @@ struct cfg80211_sched_scan_request { 
	u32 interval;

	const u8 *ie;

	size_t ie_len;

	struct cfg80211_match_set *match_sets;

	int n_match_sets;



	/* internal */

	struct wiphy *wiphy;
@@ -1814,6 +1830,9 @@ struct wiphy_wowlan_support { 
 *	any given scan

 * @max_sched_scan_ssids: maximum number of SSIDs the device can scan

 *	for in any given scheduled scan

 * @max_match_sets: maximum number of match sets the device can handle

 *	when performing a scheduled scan, 0 if filtering is not

 *	supported.

 * @max_scan_ie_len: maximum length of user-controlled IEs device can

 *	add to probe request frames transmitted during a scan, must not

 *	include fixed IEs like supported rates
@@ -1871,6 +1890,7 @@ struct wiphy { 
	int bss_priv_size;

	u8 max_scan_ssids;

	u8 max_sched_scan_ssids;

	u8 max_match_sets;

	u16 max_scan_ie_len;

	u16 max_sched_scan_ie_len;

net/wireless/nl80211.c

+58 −1
Original line number Diff line number Diff line
@@ -190,6 +190,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = { 
	[NL80211_ATTR_IE_ASSOC_RESP] = { .type = NLA_BINARY,

					 .len = IEEE80211_MAX_DATA_LEN },

	[NL80211_ATTR_ROAM_SUPPORT] = { .type = NLA_FLAG },

	[NL80211_ATTR_SCHED_SCAN_MATCH] = { .type = NLA_NESTED },

};



/* policy for the key attributes */
@@ -232,6 +233,12 @@ nl80211_rekey_policy[NUM_NL80211_REKEY_DATA] = { 
	[NL80211_REKEY_DATA_REPLAY_CTR] = { .len = NL80211_REPLAY_CTR_LEN },

};



static const struct nla_policy

nl80211_match_policy[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1] = {

	[NL80211_ATTR_SCHED_SCAN_MATCH_SSID] = { .type = NLA_BINARY,

						 .len = IEEE80211_MAX_SSID_LEN },

};



/* ifidx get helper */

static int nl80211_get_ifidx(struct netlink_callback *cb)

{
@@ -715,6 +722,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags, 
		    dev->wiphy.max_scan_ie_len);

	NLA_PUT_U16(msg, NL80211_ATTR_MAX_SCHED_SCAN_IE_LEN,

		    dev->wiphy.max_sched_scan_ie_len);

	NLA_PUT_U8(msg, NL80211_ATTR_MAX_MATCH_SETS,

		   dev->wiphy.max_match_sets);



	if (dev->wiphy.flags & WIPHY_FLAG_IBSS_RSN)

		NLA_PUT_FLAG(msg, NL80211_ATTR_SUPPORT_IBSS_RSN);
@@ -3632,10 +3641,11 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 
	struct net_device *dev = info->user_ptr[1];

	struct nlattr *attr;

	struct wiphy *wiphy;

	int err, tmp, n_ssids = 0, n_channels, i;

	int err, tmp, n_ssids = 0, n_match_sets = 0, n_channels, i;

	u32 interval;

	enum ieee80211_band band;

	size_t ie_len;

	struct nlattr *tb[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1];



	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||

	    !rdev->ops->sched_scan_start)
@@ -3674,6 +3684,15 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 
	if (n_ssids > wiphy->max_sched_scan_ssids)

		return -EINVAL;



	if (info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH])

		nla_for_each_nested(attr,

				    info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH],

				    tmp)

			n_match_sets++;



	if (n_match_sets > wiphy->max_match_sets)

		return -EINVAL;



	if (info->attrs[NL80211_ATTR_IE])

		ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);

	else
@@ -3691,6 +3710,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 


	request = kzalloc(sizeof(*request)

			+ sizeof(*request->ssids) * n_ssids

			+ sizeof(*request->match_sets) * n_match_sets

			+ sizeof(*request->channels) * n_channels

			+ ie_len, GFP_KERNEL);

	if (!request) {
@@ -3708,6 +3728,18 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 
			request->ie = (void *)(request->channels + n_channels);

	}



	if (n_match_sets) {

		if (request->ie)

			request->match_sets = (void *)(request->ie + ie_len);

		else if (request->ssids)

			request->match_sets =

				(void *)(request->ssids + n_ssids);

		else

			request->match_sets =

				(void *)(request->channels + n_channels);

	}

	request->n_match_sets = n_match_sets;



	i = 0;

	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {

		/* user specified, bail out if channel not found */
@@ -3772,6 +3804,31 @@ static int nl80211_start_sched_scan(struct sk_buff *skb, 
		}

	}



	i = 0;

	if (info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH]) {

		nla_for_each_nested(attr,

				    info->attrs[NL80211_ATTR_SCHED_SCAN_MATCH],

				    tmp) {

			struct nlattr *ssid;



			nla_parse(tb, NL80211_SCHED_SCAN_MATCH_ATTR_MAX,

				  nla_data(attr), nla_len(attr),

				  nl80211_match_policy);

			ssid = tb[NL80211_ATTR_SCHED_SCAN_MATCH_SSID];

			if (ssid) {

				if (nla_len(ssid) > IEEE80211_MAX_SSID_LEN) {

					err = -EINVAL;

					goto out_free;

				}

				memcpy(request->match_sets[i].ssid.ssid,

				       nla_data(ssid), nla_len(ssid));

				request->match_sets[i].ssid.ssid_len =

					nla_len(ssid);

			}

			i++;

		}

	}



	if (info->attrs[NL80211_ATTR_IE]) {

		request->ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);

		memcpy((void *)request->ie,

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