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: Luciano Coelho <coelho@xxxxxx>
---
This replaces "nl80211/cfg80211: add ssid filtering for sched_scan".
The commit has been renamed to better reflect the new logic.
Changes in v2:
* changed the concept to use match sets instead of different
types of filters (as discussed in v1);
include/linux/nl80211.h | 43 ++++++++++++++++++++++++++++++++++
include/net/cfg80211.h | 20 ++++++++++++++++
net/wireless/nl80211.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 121 insertions(+), 1 deletions(-)
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 3769303..4267f7b 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -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
@@ -1252,6 +1272,9 @@ enum nl80211_attrs {
NL80211_ATTR_IE_PROBE_RESP,
NL80211_ATTR_IE_ASSOC_RESP,
+ NL80211_ATTR_SCHED_SCAN_MATCH,
+ NL80211_ATTR_MAX_MATCH_SETS,
+
/* add attributes here, update the policy in nl80211.c */
__NL80211_ATTR_AFTER_LAST,
@@ -1711,6 +1734,26 @@ enum nl80211_reg_rule_attr {
};
/**
+ * 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
*
* @NL80211_RRF_NO_OFDM: OFDM modulation not allowed
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index a37f264..df8d76a 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -874,6 +874,15 @@ struct cfg80211_scan_request {
};
/**
+ * 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
*
* @ssids: SSIDs to scan for (passed in the probe_reqs in active scans)
@@ -882,6 +891,11 @@ 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
@@ -893,6 +907,8 @@ 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;
@@ -1806,6 +1822,9 @@ 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
@@ -1863,6 +1882,7 @@ 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;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 57ecfa4..9c69afd 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -189,6 +189,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
.len = IEEE80211_MAX_DATA_LEN },
[NL80211_ATTR_IE_ASSOC_RESP] = { .type = NLA_BINARY,
.len = IEEE80211_MAX_DATA_LEN },
+ [NL80211_ATTR_SCHED_SCAN_MATCH] = { .type = NLA_NESTED },
};
/* policy for the key attributes */
@@ -231,6 +232,12 @@ 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)
{
@@ -714,6 +721,8 @@ 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);
@@ -3598,10 +3607,11 @@ 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)
@@ -3640,6 +3650,15 @@ 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
@@ -3657,6 +3676,7 @@ 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) {
@@ -3674,6 +3694,18 @@ 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 */
@@ -3738,6 +3770,31 @@ 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,
--
1.7.1
--
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