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nl80211/cfg80211: add match filtering for sched_scan

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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@ti.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Luciano Coelho 2011-08-31 16:01:48 +03:00 committed by John W. Linville
parent cedb5412ba
commit a1f1c21c18
3 changed files with 121 additions and 1 deletions
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43
include/linux/nl80211.h
View file

@ -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
*

20
include/net/cfg80211.h
View file

@ -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;

59
net/wireless/nl80211.c
View file

@ -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,