nl80211: allow multiple active scheduled scan requests

This patch implements the idea to have multiple scheduled scan requests
running concurrently. It mainly illustrates how to deal with the incoming
request from user-space in terms of backward compatibility. In order to
use multiple scheduled scans user-space needs to provide a flag attribute
NL80211_ATTR_SCHED_SCAN_MULTI to indicate support. If not the request is
treated as a legacy scan.

Drivers currently supporting scheduled scan are now indicating they support
a single scheduled scan request. This obsoletes WIPHY_FLAG_SUPPORTS_SCHED_SCAN.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
[clean up netlink destroy path to avoid allocations, code cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 19 insertions, 2 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index af958938b3b1..43c0f389c273 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1678,6 +1678,8 @@ struct cfg80211_bss_select_adjust {
  * @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)
+ * @nl_owner_dead: netlink owner socket was closed - this request be freed
+ * @list: for keeping list of requests.
  * @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
@@ -1722,6 +1724,8 @@ struct cfg80211_sched_scan_request {
 	unsigned long scan_start;
 	struct rcu_head rcu_head;
 	u32 owner_nlportid;
+	bool nl_owner_dead;
+	struct list_head list;
 
 	/* keep last */
 	struct ieee80211_channel *channels[0];
@@ -3213,7 +3217,7 @@ enum wiphy_flags {
 	WIPHY_FLAG_CONTROL_PORT_PROTOCOL	= BIT(7),
 	WIPHY_FLAG_IBSS_RSN			= BIT(8),
 	WIPHY_FLAG_MESH_AUTH			= BIT(10),
-	WIPHY_FLAG_SUPPORTS_SCHED_SCAN		= BIT(11),
+	/* use hole at 11 */
 	/* use hole at 12 */
 	WIPHY_FLAG_SUPPORTS_FW_ROAM		= BIT(13),
 	WIPHY_FLAG_AP_UAPSD			= BIT(14),
@@ -3551,6 +3555,8 @@ struct wiphy_iftype_ext_capab {
  *	this variable determines its size
  * @max_scan_ssids: maximum number of SSIDs the device can scan for in
  *	any given scan
+ * @max_sched_scan_reqs: maximum number of scheduled scan requests that
+ *	the device can run concurrently.
  * @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
@@ -3687,6 +3693,7 @@ struct wiphy {
 
 	int bss_priv_size;
 	u8 max_scan_ssids;
+	u8 max_sched_scan_reqs;
 	u8 max_sched_scan_ssids;
 	u8 max_match_sets;
 	u16 max_scan_ie_len;
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 6095a6c4c412..f34127d241e5 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -387,7 +387,9 @@
  *	are used.  Extra IEs can also be passed from the userspace by
  *	using the %NL80211_ATTR_IE attribute.  The first cycle of the
  *	scheduled scan can be delayed by %NL80211_ATTR_SCHED_SCAN_DELAY
- *	is supplied.
+ *	is supplied. If the device supports multiple concurrent scheduled
+ *	scans, it will allow such when the caller provides the flag attribute
+ *	%NL80211_ATTR_SCHED_SCAN_MULTI to indicate user-space support for it.
  * @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.
@@ -2081,6 +2083,11 @@ enum nl80211_commands {
  * @NL80211_ATTR_PMK: PMK for the PMKSA identified by %NL80211_ATTR_PMKID.
  *	This is used with @NL80211_CMD_SET_PMKSA.
  *
+ * @NL80211_ATTR_SCHED_SCAN_MULTI: flag attribute which user-space shall use to
+ *	indicate that it supports multiple active scheduled scan requests.
+ * @NL80211_ATTR_SCHED_SCAN_MAX_REQS: indicates maximum number of scheduled
+ *	scan request that may be active for the device (u32).
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2500,6 +2507,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PMK,
 
+	NL80211_ATTR_SCHED_SCAN_MULTI,
+	NL80211_ATTR_SCHED_SCAN_MAX_REQS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,