nl80211: add an attribute to allow delaying the first scheduled scan cycle

The userspace may want to delay the the first scheduled scan or
net-detect cycle.  Add an optional attribute to the scheduled scan
configuration to pass the delay to be (optionally) used by the driver.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
[add the attribute to the policy to validate it]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 24 insertions, 6 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7b44ba0a7632..64e09e1e8099 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1493,6 +1493,10 @@ struct cfg80211_match_set {
  * @rcu_head: RCU callback used to free the struct
  * @owner_nlportid: netlink portid of owner (if this should is a request
  *      owned by a particular socket)
+ * @delay: delay in seconds to use before starting the first scan
+ *      cycle.  The driver may ignore this parameter and start
+ *      immediately (or at any other time), if this feature is not
+ *      supported.
  */
 struct cfg80211_sched_scan_request {
         struct cfg80211_ssid *ssids;
@@ -1506,6 +1510,7 @@ struct cfg80211_sched_scan_request {
         struct cfg80211_match_set *match_sets;
         int n_match_sets;
         s32 min_rssi_thold;
+        u32 delay;
 
         u8 mac_addr[ETH_ALEN] __aligned(2);
         u8 mac_addr_mask[ETH_ALEN] __aligned(2);
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index f68532b015db..1cbc3aae425c 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -324,7 +324,9 @@
  *      if passed, define which channels should be scanned; if not
  *      passed, all channels allowed for the current regulatory domain
  *      are used.  Extra IEs can also be passed from the userspace by
- *      using the %NL80211_ATTR_IE attribute.
+ *      using the %NL80211_ATTR_IE attribute.  The first cycle of the
+ *      scheduled scan can be delayed by %NL80211_ATTR_SCHED_SCAN_DELAY
+ *      is supplied.
  * @NL80211_CMD_STOP_SCHED_SCAN: stop a scheduled scan. Returns -ENOENT if
  *      scheduled scan is not running. The caller may assume that as soon
  *      as the call returns, it is safe to start a new scheduled scan again.
@@ -1735,6 +1737,9 @@ enum nl80211_commands {
  *      should be contained in the result as the sum of the respective counters
  *      over all channels.
  *
+ * @NL80211_ATTR_SCHED_SCAN_DELAY: delay before a scheduled scan (or a
+ *      WoWLAN net-detect scan) is started, u32 in seconds.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2100,6 +2105,8 @@ enum nl80211_attrs {
 
         NL80211_ATTR_NETNS_FD,
 
+        NL80211_ATTR_SCHED_SCAN_DELAY,
+
         /* add attributes here, update the policy in nl80211.c */
 
         __NL80211_ATTR_AFTER_LAST,
@@ -3743,11 +3750,12 @@ struct nl80211_pattern_support {
  * @NL80211_WOWLAN_TRIG_NET_DETECT: wake up when a configured network
  *      is detected.  This is a nested attribute that contains the
  *      same attributes used with @NL80211_CMD_START_SCHED_SCAN.  It
- *      specifies how the scan is performed (e.g. the interval and the
- *      channels to scan) as well as the scan results that will
- *      trigger a wake (i.e. the matchsets).  This attribute is also
- *      sent in a response to @NL80211_CMD_GET_WIPHY, indicating the
- *      number of match sets supported by the driver (u32).
+ *      specifies how the scan is performed (e.g. the interval, the
+ *      channels to scan and the initial delay) as well as the scan
+ *      results that will trigger a wake (i.e. the matchsets).  This
+ *      attribute is also sent in a response to
+ *      @NL80211_CMD_GET_WIPHY, indicating the number of match sets
+ *      supported by the driver (u32).
  * @NL80211_WOWLAN_TRIG_NET_DETECT_RESULTS: nested attribute
  *      containing an array with information about what triggered the
  *      wake up.  If no elements are present in the array, it means
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c64100ec79e3..4542e8683beb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -398,6 +398,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
         [NL80211_ATTR_MAC_MASK] = { .len = ETH_ALEN },
         [NL80211_ATTR_WIPHY_SELF_MANAGED_REG] = { .type = NLA_FLAG },
         [NL80211_ATTR_NETNS_FD] = { .type = NLA_U32 },
+        [NL80211_ATTR_SCHED_SCAN_DELAY] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -6205,6 +6206,10 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
                 }
         }
 
+        if (attrs[NL80211_ATTR_SCHED_SCAN_DELAY])
+                request->delay =
+                        nla_get_u32(attrs[NL80211_ATTR_SCHED_SCAN_DELAY]);
+
         request->interval = interval;
         request->scan_start = jiffies;