User might want to be notified with intermediate scan results only
above some minimal RSSI. Adding new NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI
u32 attribute for the intermediate scan results RSSI filtering mechanism,
which will significantly reduce unnecessary Kernel-User traffic.
It might be optionally enabled during NL80211_CMD_TRIGGER_SCAN.
Signed-off-by: Victor Goldenshtein <VictorG@xxxxxx>
---
include/linux/nl80211.h | 5 +++++
net/wireless/core.h | 1 +
net/wireless/nl80211.c | 13 +++++++++++--
net/wireless/scan.c | 4 ++++
4 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 5a10ec0..44cc394 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -1063,6 +1063,10 @@ enum nl80211_commands {
* scan result notification event (%NL80211_CMD_IM_SCAN_RESULT)
* for the %NL80211_CMD_TRIGGER_SCAN command.
* When set: will notify on each new scan result in the cache.
+ * @%NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI: Intermediate event filtering.
+ * When set: will notify only those new scan result whose signal
+ * strength of probe response/beacon (in dBm) is stronger than this
+ * negative value (usually: -20 dBm > X > -95 dBm).
*
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
@@ -1275,6 +1279,7 @@ enum nl80211_attrs {
NL80211_ATTR_IE_ASSOC_RESP,
NL80211_ATTR_IM_SCAN_RESULT,
+ NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI,
/* add attributes here, update the policy in nl80211.c */
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 7484255..bacd5b3 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -78,6 +78,7 @@ struct cfg80211_registered_device {
/* intermediate scan result configuration */
bool im_scan_result;
+ s32 im_scan_result_min_rssi_mbm;
/* must be last because of the way we do wiphy_priv(),
* and it should at least be aligned to NETDEV_ALIGN */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9e60b48..82c7b40 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -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_IM_SCAN_RESULT] = { .type = NLA_FLAG },
+ [NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI] = { .type = NLA_U32 },
};
/* policy for the key attributes */
@@ -3558,10 +3559,18 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
}
}
- if (info->attrs[NL80211_ATTR_IM_SCAN_RESULT])
+ if (info->attrs[NL80211_ATTR_IM_SCAN_RESULT]) {
rdev->im_scan_result = 1;
- else
+ if (info->attrs[NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI]) {
+ attr = info->attrs[NL80211_ATTR_IM_SCAN_RESULT_MIN_RSSI];
+ rdev->im_scan_result_min_rssi_mbm =
+ DBM_TO_MBM(nla_get_u32(attr));
+ } else {
+ rdev->im_scan_result_min_rssi_mbm = 0;
+ }
+ } else {
rdev->im_scan_result = 0;
+ }
request->dev = dev;
request->wiphy = &rdev->wiphy;
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 9be42c3..257c70a 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -183,6 +183,10 @@ void cfg80211_send_intermediate_result(struct net_device *dev,
if ((!rdev->im_scan_result) || (!rdev->scan_req) || (!cbss))
return;
+ if ((rdev->im_scan_result_min_rssi_mbm) &&
+ (rdev->im_scan_result_min_rssi_mbm > cbss->signal))
+ return;
+
ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
if (!ev)
return;
--
1.7.0.4
--
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