[PATCH v3 0/3] cfg80211/mac80211: implementation of scheduled scan

[PATCH v3 0/3] cfg80211/mac80211: implementation of scheduled scan

[Luciano Coelho]

Hi,

I found a race condition in my previous patches when scan results where queued
and we got a stop request before processing them.  I have now fixed this by
checking whether we're scanning before sending results and by not queuing new
scan results after we have stopped.

Two new changes from v2:

* make sure we still have sched_scan_req when trying to send scan results;
* don't queue scan results events if the scheduled scan is not running;

And the previous changes, from v1 were:

* fixed @ssid description in cfg80211_sched_scan_request();
* cleaned the 'out_free' inside an else block;
* use a trace event class for sched_scan_start/_stop and hw_scan;
* a couple of patches sent separately with more common trace classes;
* removed the FIF_BCN_PRBRESP_PROMISC flag on sched_scanning;
* moved conditions a bit around in ieee80211_rx_h_passive_scan(), so the
  IEEE80211_RX_IN_SCAN flag is not needed in sched_scan;
* sent a separate patch not to drop skb->len < 24 frames in scans;
* fixed freeing the ies array when the sched_scan_start driver callback fails;


Cheers,
Luca.

Luciano Coelho (3):
  cfg80211/nl80211: add support for scheduled scans
  mac80211: add support for HW scheduled scan
  cfg80211/nl80211: add interval attribute for scheduled scans

 include/linux/nl80211.h     |   32 ++++++
 include/net/cfg80211.h      |   59 ++++++++++
 include/net/mac80211.h      |   50 ++++++++
 net/mac80211/cfg.c          |   27 +++++
 net/mac80211/driver-ops.h   |   29 +++++-
 net/mac80211/driver-trace.h |   88 ++++++++++++---
 net/mac80211/ieee80211_i.h  |    9 ++
 net/mac80211/main.c         |    6 +-
 net/mac80211/rx.c           |    6 +-
 net/mac80211/scan.c         |   99 ++++++++++++++++
 net/wireless/core.c         |   12 ++-
 net/wireless/core.h         |    7 +
 net/wireless/nl80211.c      |  260 +++++++++++++++++++++++++++++++++++++++++++
 net/wireless/nl80211.h      |    4 +
 net/wireless/scan.c         |   70 ++++++++++++
 15 files changed, 735 insertions(+), 23 deletions(-)

[PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Luciano Coelho]

Implement new functionality for scheduled scan offload.  With this feature we
can scan automatically at certain intervals.

The idea is that the hardware can perform scan automatically and filter on
desired results without waking up the host unnecessarily.

Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
commands to the nl80211 interface.  When results are available they are
reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
informed when the scheduled scan has stopped with a
NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.

Signed-off-by: Luciano Coelho <coelho@ti.com>
---
 include/linux/nl80211.h |   25 +++++
 include/net/cfg80211.h  |   57 +++++++++++
 net/wireless/core.c     |   12 ++-
 net/wireless/core.h     |    7 ++
 net/wireless/nl80211.c  |  250 +++++++++++++++++++++++++++++++++++++++++++++++
 net/wireless/nl80211.h  |    4 +
 net/wireless/scan.c     |   70 +++++++++++++
 7 files changed, 424 insertions(+), 1 deletions(-)

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 109cac5..8f02fac 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -203,6 +203,26 @@
  * @NL80211_CMD_SCAN_ABORTED: scan was aborted, for unspecified reasons,
  *	partial scan results may be available
  *
+ * @NL80211_CMD_START_SCHED_SCAN: start a scheduled scan.  Like with normal
+ *	scans, if SSIDs (%NL80211_ATTR_SCAN_SSIDS) are passed, they are used
+ *	in the probe requests.  For broadcast, a broadcast SSID must be
+ *	passed (ie. an empty string).  If no SSID is passed, no probe
+ *	requests are sent and a passive scan is performed.
+ *	%NL80211_ATTR_SCAN_FREQUENCIES, 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.
+ * @NL80211_CMD_STOP_SCHED_SCAN: stop a scheduled scan
+ * @NL80211_CMD_SCHED_SCAN_RESULTS: indicates that there are scheduled scan
+ *	results available.
+ * @NL80211_CMD_SCHED_SCAN_STOPPED: indicates that the scheduled scan has
+ *	stopped.  The driver may issue this event at any time during a
+ *	scheduled scan.  One reason for stopping the scan is if the hardware
+ *	does not support starting an association or a normal scan while running
+ *	a scheduled scan.  This event is also sent when the
+ *	%NL80211_CMD_STOP_SCHED_SCAN command is received or when the interface
+ *	is brought down while a scheduled scan was running.
+ *
  * @NL80211_CMD_GET_SURVEY: get survey resuls, e.g. channel occupation
  *      or noise level
  * @NL80211_CMD_NEW_SURVEY_RESULTS: survey data notification (as a reply to
@@ -545,6 +565,11 @@ enum nl80211_commands {
 	NL80211_CMD_GET_WOWLAN,
 	NL80211_CMD_SET_WOWLAN,
 
+	NL80211_CMD_START_SCHED_SCAN,
+	NL80211_CMD_STOP_SCHED_SCAN,
+	NL80211_CMD_SCHED_SCAN_RESULTS,
+	NL80211_CMD_SCHED_SCAN_STOPPED,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0920daf..d9b92c4 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -793,6 +793,33 @@ struct cfg80211_scan_request {
 };
 
 /**
+ * struct cfg80211_sched_scan_request - scheduled scan request description
+ *
+ * @ssids: SSIDs to scan for (passed in the probe_reqs in active scans)
+ * @n_ssids: number of SSIDs
+ * @n_channels: total number of channels to scan
+ * @ie: optional information element(s) to add into Probe Request or %NULL
+ * @ie_len: length of ie in octets
+ * @wiphy: the wiphy this was for
+ * @dev: the interface
+ * @channels: channels to scan
+ */
+struct cfg80211_sched_scan_request {
+	struct cfg80211_ssid *ssids;
+	int n_ssids;
+	u32 n_channels;
+	const u8 *ie;
+	size_t ie_len;
+
+	/* internal */
+	struct wiphy *wiphy;
+	struct net_device *dev;
+
+	/* keep last */
+	struct ieee80211_channel *channels[0];
+};
+
+/**
  * enum cfg80211_signal_type - signal type
  *
  * @CFG80211_SIGNAL_TYPE_NONE: no signal strength information available
@@ -1261,6 +1288,10 @@ struct cfg80211_wowlan {
  * @set_power_mgmt: Configure WLAN power management. A timeout value of -1
  *	allows the driver to adjust the dynamic ps timeout value.
  * @set_cqm_rssi_config: Configure connection quality monitor RSSI threshold.
+ * @sched_scan_start: Tell the driver to start a scheduled scan.
+ * @sched_scan_stop: Tell the driver to stop an ongoing scheduled
+ *	scan.  The driver_initiated flag specifies whether the driver
+ *	itself has informed that the scan has stopped.
  *
  * @mgmt_frame_register: Notify driver that a management frame type was
  *	registered. Note that this callback may not sleep, and cannot run
@@ -1447,6 +1478,12 @@ struct cfg80211_ops {
 	int	(*set_ringparam)(struct wiphy *wiphy, u32 tx, u32 rx);
 	void	(*get_ringparam)(struct wiphy *wiphy,
 				 u32 *tx, u32 *tx_max, u32 *rx, u32 *rx_max);
+
+	int	(*sched_scan_start)(struct wiphy *wiphy,
+				struct net_device *dev,
+				struct cfg80211_sched_scan_request *request);
+	int	(*sched_scan_stop)(struct wiphy *wiphy, struct net_device *dev,
+				   bool driver_initiated);
 };
 
 /*
@@ -1491,6 +1528,7 @@ struct cfg80211_ops {
  * @WIPHY_FLAG_IBSS_RSN: The device supports IBSS RSN.
  * @WIPHY_FLAG_MESH_AUTH: The device supports mesh authentication by routing
  *	auth frames to userspace. See @NL80211_MESH_SETUP_USERSPACE_AUTH.
+ * @WIPHY_FLAG_SCHED_SCAN: The device supports scheduled scans.
  */
 enum wiphy_flags {
 	WIPHY_FLAG_CUSTOM_REGULATORY		= BIT(0),
@@ -1503,6 +1541,7 @@ 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),
 };
 
 struct mac_address {
@@ -2324,6 +2363,24 @@ int cfg80211_wext_siwpmksa(struct net_device *dev,
 void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted);
 
 /**
+ * cfg80211_sched_scan_results - notify that new scan results are available
+ *
+ * @wiphy: the wiphy which got scheduled scan results
+ */
+void cfg80211_sched_scan_results(struct wiphy *wiphy);
+
+/**
+ * cfg80211_sched_scan_stopped - notify that the scheduled scan has stopped
+ *
+ * @wiphy: the wiphy on which the scheduled scan stopped
+ *
+ * The driver can call this function to inform cfg80211 that the
+ * scheduled scan had to be stopped, for whatever reason.  The driver
+ * is then called back via the sched_scan_stop operation when done.
+ */
+void cfg80211_sched_scan_stopped(struct wiphy *wiphy);
+
+/**
  * cfg80211_inform_bss_frame - inform cfg80211 of a received BSS frame
  *
  * @wiphy: the wiphy reporting the BSS
diff --git a/net/wireless/core.c b/net/wireless/core.c
index bea0d80..f924a49 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -370,7 +370,8 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
 	spin_lock_init(&rdev->bss_lock);
 	INIT_LIST_HEAD(&rdev->bss_list);
 	INIT_WORK(&rdev->scan_done_wk, __cfg80211_scan_done);
-
+	INIT_WORK(&rdev->sched_scan_results_wk, __cfg80211_sched_scan_results);
+	INIT_WORK(&rdev->sched_scan_stopped_wk, __cfg80211_sched_scan_stopped);
 #ifdef CONFIG_CFG80211_WEXT
 	rdev->wiphy.wext = &cfg80211_wext_handler;
 #endif
@@ -672,6 +673,11 @@ static void wdev_cleanup_work(struct work_struct *work)
 		___cfg80211_scan_done(rdev, true);
 	}
 
+	if (WARN_ON(rdev->sched_scan_req &&
+		    rdev->sched_scan_req->dev == wdev->netdev)) {
+		__cfg80211_stop_sched_scan(rdev, false);
+	}
+
 	cfg80211_unlock_rdev(rdev);
 
 	mutex_lock(&rdev->devlist_mtx);
@@ -759,6 +765,10 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 			break;
 		case NL80211_IFTYPE_P2P_CLIENT:
 		case NL80211_IFTYPE_STATION:
+			cfg80211_lock_rdev(rdev);
+			__cfg80211_stop_sched_scan(rdev, false);
+			cfg80211_unlock_rdev(rdev);
+
 			wdev_lock(wdev);
 #ifdef CONFIG_CFG80211_WEXT
 			kfree(wdev->wext.ie);
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 7a18c10..e3f7b1d 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -60,8 +60,11 @@ struct cfg80211_registered_device {
 	struct rb_root bss_tree;
 	u32 bss_generation;
 	struct cfg80211_scan_request *scan_req; /* protected by RTNL */
+	struct cfg80211_sched_scan_request *sched_scan_req;
 	unsigned long suspend_at;
 	struct work_struct scan_done_wk;
+	struct work_struct sched_scan_results_wk;
+	struct work_struct sched_scan_stopped_wk;
 
 #ifdef CONFIG_NL80211_TESTMODE
 	struct genl_info *testmode_info;
@@ -411,6 +414,10 @@ void cfg80211_sme_rx_auth(struct net_device *dev, const u8 *buf, size_t len);
 void cfg80211_sme_disassoc(struct net_device *dev, int idx);
 void __cfg80211_scan_done(struct work_struct *wk);
 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak);
+void __cfg80211_sched_scan_results(struct work_struct *wk);
+int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
+			       bool driver_initiated);
+void __cfg80211_sched_scan_stopped(struct work_struct *wk);
 void cfg80211_upload_connect_keys(struct wireless_dev *wdev);
 int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 			  struct net_device *dev, enum nl80211_iftype ntype,
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0a199a1..0c32faf 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -759,6 +759,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	}
 	CMD(set_channel, SET_CHANNEL);
 	CMD(set_wds_peer, SET_WDS_PEER);
+	if (dev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+		CMD(sched_scan_start, START_SCHED_SCAN);
 
 #undef CMD
 
@@ -3349,6 +3351,179 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+static int nl80211_start_sched_scan(struct sk_buff *skb,
+				    struct genl_info *info)
+{
+	struct cfg80211_sched_scan_request *request;
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct cfg80211_ssid *ssid;
+	struct ieee80211_channel *channel;
+	struct nlattr *attr;
+	struct wiphy *wiphy;
+	int err, tmp, n_ssids = 0, n_channels, i;
+	enum ieee80211_band band;
+	size_t ie_len;
+
+	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
+	    !rdev->ops->sched_scan_start)
+		return -EOPNOTSUPP;
+
+	if (!is_valid_ie_attr(info->attrs[NL80211_ATTR_IE]))
+		return -EINVAL;
+
+	if (rdev->sched_scan_req)
+		return -EINPROGRESS;
+
+	wiphy = &rdev->wiphy;
+
+	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+		n_channels = validate_scan_freqs(
+				info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]);
+		if (!n_channels)
+			return -EINVAL;
+	} else {
+		n_channels = 0;
+
+		for (band = 0; band < IEEE80211_NUM_BANDS; band++)
+			if (wiphy->bands[band])
+				n_channels += wiphy->bands[band]->n_channels;
+	}
+
+	if (info->attrs[NL80211_ATTR_SCAN_SSIDS])
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS],
+				    tmp)
+			n_ssids++;
+
+	if (n_ssids > wiphy->max_scan_ssids)
+		return -EINVAL;
+
+	if (info->attrs[NL80211_ATTR_IE])
+		ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
+	else
+		ie_len = 0;
+
+	if (ie_len > wiphy->max_scan_ie_len)
+		return -EINVAL;
+
+	request = kzalloc(sizeof(*request)
+			+ sizeof(*ssid) * n_ssids
+			+ sizeof(channel) * n_channels
+			+ ie_len, GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	if (n_ssids)
+		request->ssids = (void *)&request->channels[n_channels];
+	request->n_ssids = n_ssids;
+	if (ie_len) {
+		if (request->ssids)
+			request->ie = (void *)(request->ssids + n_ssids);
+		else
+			request->ie = (void *)(request->channels + n_channels);
+	}
+
+	i = 0;
+	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
+		/* user specified, bail out if channel not found */
+		nla_for_each_nested(attr,
+				    info->attrs[NL80211_ATTR_SCAN_FREQUENCIES],
+				    tmp) {
+			struct ieee80211_channel *chan;
+
+			chan = ieee80211_get_channel(wiphy, nla_get_u32(attr));
+
+			if (!chan) {
+				err = -EINVAL;
+				goto out_free;
+			}
+
+			/* ignore disabled channels */
+			if (chan->flags & IEEE80211_CHAN_DISABLED)
+				continue;
+
+			request->channels[i] = chan;
+			i++;
+		}
+	} else {
+		/* all channels */
+		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+			int j;
+			if (!wiphy->bands[band])
+				continue;
+			for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
+				struct ieee80211_channel *chan;
+
+				chan = &wiphy->bands[band]->channels[j];
+
+				if (chan->flags & IEEE80211_CHAN_DISABLED)
+					continue;
+
+				request->channels[i] = chan;
+				i++;
+			}
+		}
+	}
+
+	if (!i) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	request->n_channels = i;
+
+	i = 0;
+	if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {
+		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS],
+				    tmp) {
+			if (request->ssids[i].ssid_len >
+			    IEEE80211_MAX_SSID_LEN) {
+				err = -EINVAL;
+				goto out_free;
+			}
+			memcpy(request->ssids[i].ssid, nla_data(attr),
+			       nla_len(attr));
+			request->ssids[i].ssid_len = nla_len(attr);
+			i++;
+		}
+	}
+
+	if (info->attrs[NL80211_ATTR_IE]) {
+		request->ie_len = nla_len(info->attrs[NL80211_ATTR_IE]);
+		memcpy((void *)request->ie,
+		       nla_data(info->attrs[NL80211_ATTR_IE]),
+		       request->ie_len);
+	}
+
+	request->dev = dev;
+	request->wiphy = &rdev->wiphy;
+
+	err = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
+	if (!err) {
+		rdev->sched_scan_req = request;
+		nl80211_send_sched_scan(rdev, dev,
+					NL80211_CMD_START_SCHED_SCAN);
+		goto out;
+	}
+
+out_free:
+	kfree(request);
+out:
+	return err;
+}
+
+static int nl80211_stop_sched_scan(struct sk_buff *skb,
+				   struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+
+	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
+	    !rdev->ops->sched_scan_stop)
+		return -EOPNOTSUPP;
+
+	return __cfg80211_stop_sched_scan(rdev, false);
+}
+
 static int nl80211_send_bss(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 			    struct cfg80211_registered_device *rdev,
 			    struct wireless_dev *wdev,
@@ -5319,6 +5494,22 @@ static struct genl_ops nl80211_ops[] = {
 		.dumpit = nl80211_dump_scan,
 	},
 	{
+		.cmd = NL80211_CMD_START_SCHED_SCAN,
+		.doit = nl80211_start_sched_scan,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL80211_CMD_STOP_SCHED_SCAN,
+		.doit = nl80211_stop_sched_scan,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
+	{
 		.cmd = NL80211_CMD_AUTHENTICATE,
 		.doit = nl80211_authenticate,
 		.policy = nl80211_policy,
@@ -5644,6 +5835,28 @@ static int nl80211_send_scan_msg(struct sk_buff *msg,
 	return -EMSGSIZE;
 }
 
+static int
+nl80211_send_sched_scan_msg(struct sk_buff *msg,
+			    struct cfg80211_registered_device *rdev,
+			    struct net_device *netdev,
+			    u32 pid, u32 seq, int flags, u32 cmd)
+{
+	void *hdr;
+
+	hdr = nl80211hdr_put(msg, pid, seq, flags, cmd);
+	if (!hdr)
+		return -1;
+
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx);
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex);
+
+	return genlmsg_end(msg, hdr);
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
 void nl80211_send_scan_start(struct cfg80211_registered_device *rdev,
 			     struct net_device *netdev)
 {
@@ -5701,6 +5914,43 @@ void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
 				nl80211_scan_mcgrp.id, GFP_KERNEL);
 }
 
+void nl80211_send_sched_scan_results(struct cfg80211_registered_device *rdev,
+				     struct net_device *netdev)
+{
+	struct sk_buff *msg;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	if (nl80211_send_sched_scan_msg(msg, rdev, netdev, 0, 0, 0,
+					NL80211_CMD_SCHED_SCAN_RESULTS) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+				nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
+void nl80211_send_sched_scan(struct cfg80211_registered_device *rdev,
+			     struct net_device *netdev, u32 cmd)
+{
+	struct sk_buff *msg;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	if (nl80211_send_sched_scan_msg(msg, rdev, netdev, 0, 0, 0, cmd) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+				nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
 /*
  * This can happen on global regulatory changes or device specific settings
  * based on custom world regulatory domains.
diff --git a/net/wireless/nl80211.h b/net/wireless/nl80211.h
index f2af695..2f1bfb8 100644
--- a/net/wireless/nl80211.h
+++ b/net/wireless/nl80211.h
@@ -12,6 +12,10 @@ void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
 			    struct net_device *netdev);
 void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
 			       struct net_device *netdev);
+void nl80211_send_sched_scan(struct cfg80211_registered_device *rdev,
+			     struct net_device *netdev, u32 cmd);
+void nl80211_send_sched_scan_results(struct cfg80211_registered_device *rdev,
+				     struct net_device *netdev);
 void nl80211_send_reg_change_event(struct regulatory_request *request);
 void nl80211_send_rx_auth(struct cfg80211_registered_device *rdev,
 			  struct net_device *netdev,
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index fbf6f33..0275bbc 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -93,6 +93,76 @@ void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
 }
 EXPORT_SYMBOL(cfg80211_scan_done);
 
+void __cfg80211_sched_scan_results(struct work_struct *wk)
+{
+	struct cfg80211_registered_device *rdev;
+
+	rdev = container_of(wk, struct cfg80211_registered_device,
+			    sched_scan_results_wk);
+
+	cfg80211_lock_rdev(rdev);
+
+	/* we don't have sched_scan_req anymore if the scan is stopping */
+	if (rdev->sched_scan_req)
+		nl80211_send_sched_scan_results(rdev,
+						rdev->sched_scan_req->dev);
+
+	cfg80211_unlock_rdev(rdev);
+}
+
+void cfg80211_sched_scan_results(struct wiphy *wiphy)
+{
+	/* ignore if we're not scanning */
+	if (wiphy_to_dev(wiphy)->sched_scan_req)
+		queue_work(cfg80211_wq,
+			   &wiphy_to_dev(wiphy)->sched_scan_results_wk);
+}
+EXPORT_SYMBOL(cfg80211_sched_scan_results);
+
+void __cfg80211_sched_scan_stopped(struct work_struct *wk)
+{
+	struct cfg80211_registered_device *rdev;
+
+	rdev = container_of(wk, struct cfg80211_registered_device,
+			    sched_scan_stopped_wk);
+
+	cfg80211_lock_rdev(rdev);
+	__cfg80211_stop_sched_scan(rdev, true);
+	cfg80211_unlock_rdev(rdev);
+}
+
+void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
+{
+	queue_work(cfg80211_wq, &wiphy_to_dev(wiphy)->sched_scan_stopped_wk);
+}
+EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
+
+int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
+			       bool driver_initiated)
+{
+	int err;
+	struct net_device *dev;
+
+	ASSERT_RDEV_LOCK(rdev);
+
+	if (!rdev->sched_scan_req)
+		return 0;
+
+	dev = rdev->sched_scan_req->dev;
+
+	err = rdev->ops->sched_scan_stop(&rdev->wiphy, dev,
+					 driver_initiated);
+	if (err)
+		return err;
+
+	nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
+
+	kfree(rdev->sched_scan_req);
+	rdev->sched_scan_req = NULL;
+
+	return err;
+}
+
 static void bss_release(struct kref *ref)
 {
 	struct cfg80211_internal_bss *bss;
-- 
1.7.1

Re: [PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Stanislaw Gruszka]

On Wed, May 11, 2011 at 05:09:35PM +0300, Luciano Coelho wrote:
> Implement new functionality for scheduled scan offload.  With this feature we
> can scan automatically at certain intervals.
> 
> The idea is that the hardware can perform scan automatically and filter on
> desired results without waking up the host unnecessarily.

Can you elaborate more about this?

> Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
> commands to the nl80211 interface.  When results are available they are
> reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
> informed when the scheduled scan has stopped with a
> NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
> the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.
> 
> Signed-off-by: Luciano Coelho <coelho@ti.com>
> ---
>  include/linux/nl80211.h |   25 +++++
>  include/net/cfg80211.h  |   57 +++++++++++
>  net/wireless/core.c     |   12 ++-
>  net/wireless/core.h     |    7 ++
>  net/wireless/nl80211.c  |  250 +++++++++++++++++++++++++++++++++++++++++++++++
>  net/wireless/nl80211.h  |    4 +
>  net/wireless/scan.c     |   70 +++++++++++++
>  7 files changed, 424 insertions(+), 1 deletions(-)

And explain, why all of this is needed, instead of modify existing scan
code and reuse existing infrastructure. This sched_scan does not seems to
be something different than normal hardware scan we have already, or I'm
wrong.

Thanks
Stanislaw

Re: [PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Luciano Coelho]

On Thu, 2011-05-12 at 17:05 +0200, Stanislaw Gruszka wrote:
> On Wed, May 11, 2011 at 05:09:35PM +0300, Luciano Coelho wrote:
> > Implement new functionality for scheduled scan offload.  With this feature we
> > can scan automatically at certain intervals.
> > 
> > The idea is that the hardware can perform scan automatically and filter on
> > desired results without waking up the host unnecessarily.
> 
> Can you elaborate more about this?

Some devices require very low power consumption, like mobile phones and
other mobile devices, as you know. ;)

With this feature, we can offload the scanning entirely to the wireless
chip, when we're not connected but looking for APs to connect to, so the
host can keep sleeping and consuming very low power.

Let's say you're looking for an AP with SSID "myap".  You can keep your
device scanning for it, so that it's able to connect automatically when
it shows up without having to keep your device's main CPU awake and
consuming power.  When "myap" shows in the scan results, the main CPU is
awoken and the device can connect to it.

This is also useful when connected and scanning for better access points
to roam to.

This patchset is just the first step, so not much is supported, but I'm
already working on more features that will allow you to choose a list of
SSIDs to scan for, so you can keep scanning for all SSIDs your device
already knows and automatically wake up when one (or more) of them is
(or are) found.


> > Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
> > commands to the nl80211 interface.  When results are available they are
> > reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
> > informed when the scheduled scan has stopped with a
> > NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
> > the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.
> > 
> > Signed-off-by: Luciano Coelho <coelho@ti.com>
> > ---
> >  include/linux/nl80211.h |   25 +++++
> >  include/net/cfg80211.h  |   57 +++++++++++
> >  net/wireless/core.c     |   12 ++-
> >  net/wireless/core.h     |    7 ++
> >  net/wireless/nl80211.c  |  250 +++++++++++++++++++++++++++++++++++++++++++++++
> >  net/wireless/nl80211.h  |    4 +
> >  net/wireless/scan.c     |   70 +++++++++++++
> >  7 files changed, 424 insertions(+), 1 deletions(-)
> 
> And explain, why all of this is needed, instead of modify existing scan
> code and reuse existing infrastructure. This sched_scan does not seems to
> be something different than normal hardware scan we have already, or I'm
> wrong.

It is something different.  At first, I was thinking about modifying the
existing scan mechanism.  But it turned out to be too complicated,
because the scheduled scan is a long-term operation and the normal scan
is done for a very short time (and the rest of the stack assumes it will
complete quickly enough as not to interfere with the connection.

-- 
Cheers,
Luca.

Re: [PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Stanislaw Gruszka]

On Thu, May 12, 2011 at 07:20:01PM +0300, Luciano Coelho wrote:
> > > The idea is that the hardware can perform scan automatically and filter on
> > > desired results without waking up the host unnecessarily.
> > 
> > Can you elaborate more about this?
> 
> Some devices require very low power consumption, like mobile phones and
> other mobile devices, as you know. ;)
> 
> With this feature, we can offload the scanning entirely to the wireless
> chip, when we're not connected but looking for APs to connect to, so the
> host can keep sleeping and consuming very low power.
> 
> Let's say you're looking for an AP with SSID "myap".  You can keep your
> device scanning for it, so that it's able to connect automatically when
> it shows up without having to keep your device's main CPU awake and
> consuming power.  When "myap" shows in the scan results, the main CPU is
> awoken and the device can connect to it.

I see, thanks for the explanations.

> > > Add NL80211_CMD_START_SCHED_SCAN and NL80211_CMD_STOP_SCHED_SCAN
> > > commands to the nl80211 interface.  When results are available they are
> > > reported by NL80211_CMD_SCHED_SCAN_RESULTS events.  The userspace is
> > > informed when the scheduled scan has stopped with a
> > > NL80211_CMD_SCHED_SCAN_STOPPED event, which can be triggered either by
> > > the driver or by a call to NL80211_CMD_STOP_SCHED_SCAN.
> > > 
> > > Signed-off-by: Luciano Coelho <coelho@ti.com>
> > > ---
> > >  include/linux/nl80211.h |   25 +++++
> > >  include/net/cfg80211.h  |   57 +++++++++++
> > >  net/wireless/core.c     |   12 ++-
> > >  net/wireless/core.h     |    7 ++
> > >  net/wireless/nl80211.c  |  250 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  net/wireless/nl80211.h  |    4 +
> > >  net/wireless/scan.c     |   70 +++++++++++++
> > >  7 files changed, 424 insertions(+), 1 deletions(-)
> > 
> > And explain, why all of this is needed, instead of modify existing scan
> > code and reuse existing infrastructure. This sched_scan does not seems to
> > be something different than normal hardware scan we have already, or I'm
> > wrong.
> 
> It is something different.  At first, I was thinking about modifying the
> existing scan mechanism.  But it turned out to be too complicated,

I wonder if at least at user space we could have some consolidations, i.e.
merge NL80211_CMD_START_SCHED_SCAN to NL80211_CMD_TRIGGER_SCAN, and
create new command NL80211_CMD_CANCEL_SCAN like NL80211_CMD_STOP_SCHED_SCAN
but worked also on normal scan. Anyway this probably does not matter now,
since patches were applied, and we have that API now.

> because the scheduled scan is a long-term operation and the normal scan
> is done for a very short time (and the rest of the stack assumes it will
> complete quickly enough as not to interfere with the connection.

Hmm, is this drawback of implementation or can not be done technically
(question to myself :-) ? I can image that in ideal case hardware scanning
will not affect normal operation, no matter how long it will take.
Software scan is much worse, since we have to change channels manually.
We currently share code between software scan and hardware scan in
mac80211. Perhaps separating hw and sw scan code, would be a good idea
and allow to consolidate hw scan and sched scan. I planning to look
at this more closely.

Thanks
Stanislaw

Re: [PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Johannes Berg]

On Fri, 2011-05-13 at 12:45 +0200, Stanislaw Gruszka wrote:

> > because the scheduled scan is a long-term operation and the normal scan
> > is done for a very short time (and the rest of the stack assumes it will
> > complete quickly enough as not to interfere with the connection.
> 
> Hmm, is this drawback of implementation or can not be done technically
> (question to myself :-) ? I can image that in ideal case hardware scanning
> will not affect normal operation, no matter how long it will take.
> Software scan is much worse, since we have to change channels manually.
> We currently share code between software scan and hardware scan in
> mac80211. Perhaps separating hw and sw scan code, would be a good idea
> and allow to consolidate hw scan and sched scan. I planning to look
> at this more closely.

Well, it's also a semantic question. If you trigger a scan, you expect a
result (or an abort) after a while. It could of course be extended with
a new attribute, but the error checking for that gets complicated,
especially if you consider older kernels that would simply ignore that
new attribute.

So basically, the only difference between "trigger scan (scheduled=1)"
and "trigger scheduled scan" (which this implements) would be in
nl80211. Everything else would have to separate them, since there are a
lot of internal things that behave differently depending on whether a
scan is running or not. Add the error checking, and I think we've got a
good case for new API :)

Also, you don't want to implement the scheduled scan in mac80211. This
is a powersaving feature, so that doesn't make sense, and if some
application _really_ needs to emulate it then it can do that itself, it
doesn't need mac80211 to do it for it.

johannes

Re: [PATCH v3 1/3] cfg80211/nl80211: add support for scheduled scans

[Luciano Coelho]

On Fri, 2011-05-13 at 12:52 +0200, Johannes Berg wrote:
> On Fri, 2011-05-13 at 12:45 +0200, Stanislaw Gruszka wrote:
> 
> > > because the scheduled scan is a long-term operation and the normal scan
> > > is done for a very short time (and the rest of the stack assumes it will
> > > complete quickly enough as not to interfere with the connection.
> > 
> > Hmm, is this drawback of implementation or can not be done technically
> > (question to myself :-) ? I can image that in ideal case hardware scanning
> > will not affect normal operation, no matter how long it will take.
> > Software scan is much worse, since we have to change channels manually.
> > We currently share code between software scan and hardware scan in
> > mac80211. Perhaps separating hw and sw scan code, would be a good idea
> > and allow to consolidate hw scan and sched scan. I planning to look
> > at this more closely.
> 
> Well, it's also a semantic question. If you trigger a scan, you expect a
> result (or an abort) after a while. It could of course be extended with
> a new attribute, but the error checking for that gets complicated,
> especially if you consider older kernels that would simply ignore that
> new attribute.
> 
> So basically, the only difference between "trigger scan (scheduled=1)"
> and "trigger scheduled scan" (which this implements) would be in
> nl80211. Everything else would have to separate them, since there are a
> lot of internal things that behave differently depending on whether a
> scan is running or not. Add the error checking, and I think we've got a
> good case for new API :)

I agree.  I think it's better to keep it simpler with a new command.
Especially because the scheduled scan command will be extended with a
few more arguments, which may not make sense with normal scans, such as
filters etc.

-- 
Cheers,
Luca.

[PATCH v3 2/3] mac80211: add support for HW scheduled scan

[Luciano Coelho]

Implement support for HW scheduled scan.  The mac80211 code doesn't perform
scheduled scans itself, but calls the driver to start and stop scheduled
scans.

This patch also creates a trace event class to be used by drv_hw_scan
and the new drv_sched_scan_start and drv_sched_stop functions, in
order to avoid duplicate code.

Signed-off-by: Luciano Coelho <coelho@ti.com>
---
 include/net/mac80211.h      |   50 ++++++++++++++++++++++
 net/mac80211/cfg.c          |   27 ++++++++++++
 net/mac80211/driver-ops.h   |   29 ++++++++++++-
 net/mac80211/driver-trace.h |   88 ++++++++++++++++++++++++++++++--------
 net/mac80211/ieee80211_i.h  |    9 ++++
 net/mac80211/main.c         |    6 ++-
 net/mac80211/rx.c           |    6 ++-
 net/mac80211/scan.c         |   99 +++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 292 insertions(+), 22 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index f2ef7c2..8c7189c 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -537,6 +537,21 @@ struct ieee80211_tx_info {
 	};
 };
 
+/**
+ * ieee80211_sched_scan_ies - scheduled scan IEs
+ *
+ * This structure is used to pass the appropriate IEs to be used in scheduled
+ * scans for all bands.  It contains both the IEs passed from the userspace
+ * and the ones generated by mac80211.
+ *
+ * @ie: array with the IEs for each supported band
+ * @len: array with the total length of the IEs for each band
+ */
+struct ieee80211_sched_scan_ies {
+	u8 *ie[IEEE80211_NUM_BANDS];
+	size_t len[IEEE80211_NUM_BANDS];
+};
+
 static inline struct ieee80211_tx_info *IEEE80211_SKB_CB(struct sk_buff *skb)
 {
 	return (struct ieee80211_tx_info *)skb->cb;
@@ -1693,6 +1708,13 @@ enum ieee80211_ampdu_mlme_action {
  *	any error unless this callback returned a negative error code.
  *	The callback can sleep.
  *
+ * @sched_scan_start: Ask the hardware to start scanning repeatedly at
+ *	specific intervals.  The driver must call the
+ *	ieee80211_sched_scan_results() function whenever it finds results.
+ *	This process will continue until sched_scan_stop is called.
+ *
+ * @sched_scan_stop: Tell the hardware to stop an ongoing scheduled scan.
+ *
  * @sw_scan_start: Notifier function that is called just before a software scan
  *	is started. Can be NULL, if the driver doesn't need this notification.
  *	The callback can sleep.
@@ -1877,6 +1899,12 @@ struct ieee80211_ops {
 				u32 iv32, u16 *phase1key);
 	int (*hw_scan)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		       struct cfg80211_scan_request *req);
+	int (*sched_scan_start)(struct ieee80211_hw *hw,
+				struct ieee80211_vif *vif,
+				struct cfg80211_sched_scan_request *req,
+				struct ieee80211_sched_scan_ies *ies);
+	void (*sched_scan_stop)(struct ieee80211_hw *hw,
+			       struct ieee80211_vif *vif);
 	void (*sw_scan_start)(struct ieee80211_hw *hw);
 	void (*sw_scan_complete)(struct ieee80211_hw *hw);
 	int (*get_stats)(struct ieee80211_hw *hw,
@@ -2594,6 +2622,28 @@ void ieee80211_wake_queues(struct ieee80211_hw *hw);
 void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted);
 
 /**
+ * ieee80211_sched_scan_results - got results from scheduled scan
+ *
+ * When a scheduled scan is running, this function needs to be called by the
+ * driver whenever there are new scan results available.
+ *
+ * @hw: the hardware that is performing scheduled scans
+ */
+void ieee80211_sched_scan_results(struct ieee80211_hw *hw);
+
+/**
+ * ieee80211_sched_scan_stopped - inform that the scheduled scan has stopped
+ *
+ * When a scheduled scan is running, this function can be called by
+ * the driver if it needs to stop the scan to perform another task.
+ * Usual scenarios are drivers that cannot continue the scheduled scan
+ * while associating, for instance.
+ *
+ * @hw: the hardware that is performing scheduled scans
+ */
+void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw);
+
+/**
  * ieee80211_iterate_active_interfaces - iterate active interfaces
  *
  * This function iterates over the interfaces associated with a given
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 1ebc133..9e0a9a2 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1343,6 +1343,31 @@ static int ieee80211_scan(struct wiphy *wiphy,
 	return ieee80211_request_scan(sdata, req);
 }
 
+static int
+ieee80211_sched_scan_start(struct wiphy *wiphy,
+			   struct net_device *dev,
+			   struct cfg80211_sched_scan_request *req)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+	if (!sdata->local->ops->sched_scan_start)
+		return -EOPNOTSUPP;
+
+	return ieee80211_request_sched_scan_start(sdata, req);
+}
+
+static int
+ieee80211_sched_scan_stop(struct wiphy *wiphy, struct net_device *dev,
+			  bool driver_initiated)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+	if (!sdata->local->ops->sched_scan_stop)
+		return -EOPNOTSUPP;
+
+	return ieee80211_request_sched_scan_stop(sdata, driver_initiated);
+}
+
 static int ieee80211_auth(struct wiphy *wiphy, struct net_device *dev,
 			  struct cfg80211_auth_request *req)
 {
@@ -2084,6 +2109,8 @@ struct cfg80211_ops mac80211_config_ops = {
 	.suspend = ieee80211_suspend,
 	.resume = ieee80211_resume,
 	.scan = ieee80211_scan,
+	.sched_scan_start = ieee80211_sched_scan_start,
+	.sched_scan_stop = ieee80211_sched_scan_stop,
 	.auth = ieee80211_auth,
 	.assoc = ieee80211_assoc,
 	.deauth = ieee80211_deauth,
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index aa16bd8..eebf7a6 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -212,12 +212,39 @@ static inline int drv_hw_scan(struct ieee80211_local *local,
 
 	might_sleep();
 
-	trace_drv_hw_scan(local, sdata, req);
+	trace_drv_hw_scan(local, sdata);
 	ret = local->ops->hw_scan(&local->hw, &sdata->vif, req);
 	trace_drv_return_int(local, ret);
 	return ret;
 }
 
+static inline int
+drv_sched_scan_start(struct ieee80211_local *local,
+		     struct ieee80211_sub_if_data *sdata,
+		     struct cfg80211_sched_scan_request *req,
+		     struct ieee80211_sched_scan_ies *ies)
+{
+	int ret;
+
+	might_sleep();
+
+	trace_drv_sched_scan_start(local, sdata);
+	ret = local->ops->sched_scan_start(&local->hw, &sdata->vif,
+					      req, ies);
+	trace_drv_return_int(local, ret);
+	return ret;
+}
+
+static inline void drv_sched_scan_stop(struct ieee80211_local *local,
+				       struct ieee80211_sub_if_data *sdata)
+{
+	might_sleep();
+
+	trace_drv_sched_scan_stop(local, sdata);
+	local->ops->sched_scan_stop(&local->hw, &sdata->vif);
+	trace_drv_return_void(local);
+}
+
 static inline void drv_sw_scan_start(struct ieee80211_local *local)
 {
 	might_sleep();
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index dd9779d..ed9edcb 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -98,6 +98,27 @@ DECLARE_EVENT_CLASS(local_u32_evt,
 	)
 );
 
+DECLARE_EVENT_CLASS(local_sdata_evt,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		VIF_ENTRY
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		VIF_ASSIGN;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT VIF_PR_FMT,
+		LOCAL_PR_ARG, VIF_PR_ARG
+	)
+);
+
 DEFINE_EVENT(local_only_evt, drv_return_void,
 	TP_PROTO(struct ieee80211_local *local),
 	TP_ARGS(local)
@@ -433,27 +454,22 @@ TRACE_EVENT(drv_update_tkip_key,
 	)
 );
 
-TRACE_EVENT(drv_hw_scan,
+DEFINE_EVENT(local_sdata_evt, drv_hw_scan,
 	TP_PROTO(struct ieee80211_local *local,
-		 struct ieee80211_sub_if_data *sdata,
-		 struct cfg80211_scan_request *req),
-
-	TP_ARGS(local, sdata, req),
-
-	TP_STRUCT__entry(
-		LOCAL_ENTRY
-		VIF_ENTRY
-	),
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata)
+);
 
-	TP_fast_assign(
-		LOCAL_ASSIGN;
-		VIF_ASSIGN;
-	),
+DEFINE_EVENT(local_sdata_evt, drv_sched_scan_start,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata)
+);
 
-	TP_printk(
-		LOCAL_PR_FMT VIF_PR_FMT,
-		LOCAL_PR_ARG,VIF_PR_ARG
-	)
+DEFINE_EVENT(local_sdata_evt, drv_sched_scan_stop,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata)
 );
 
 DEFINE_EVENT(local_only_evt, drv_sw_scan_start,
@@ -1180,6 +1196,42 @@ TRACE_EVENT(api_scan_completed,
 	)
 );
 
+TRACE_EVENT(api_sched_scan_results,
+	TP_PROTO(struct ieee80211_local *local),
+
+	TP_ARGS(local),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT, LOCAL_PR_ARG
+	)
+);
+
+TRACE_EVENT(api_sched_scan_stopped,
+	TP_PROTO(struct ieee80211_local *local),
+
+	TP_ARGS(local),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT, LOCAL_PR_ARG
+	)
+);
+
 TRACE_EVENT(api_sta_block_awake,
 	TP_PROTO(struct ieee80211_local *local,
 		 struct ieee80211_sta *sta, bool block),
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a0d3ab2..750054c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -843,6 +843,9 @@ struct ieee80211_local {
 	int scan_channel_idx;
 	int scan_ies_len;
 
+	bool sched_scanning;
+	struct ieee80211_sched_scan_ies sched_scan_ies;
+
 	unsigned long leave_oper_channel_time;
 	enum mac80211_scan_state next_scan_state;
 	struct delayed_work scan_work;
@@ -1150,6 +1153,12 @@ ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
 void ieee80211_rx_bss_put(struct ieee80211_local *local,
 			  struct ieee80211_bss *bss);
 
+/* scheduled scan handling */
+int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
+				       struct cfg80211_sched_scan_request *req);
+int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata,
+				      bool driver_initiated);
+
 /* off-channel helpers */
 bool ieee80211_cfg_on_oper_channel(struct ieee80211_local *local);
 void ieee80211_offchannel_enable_all_ps(struct ieee80211_local *local,
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index cb326d3..fda89d3 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -358,7 +358,8 @@ static void ieee80211_restart_work(struct work_struct *work)
 	flush_workqueue(local->workqueue);
 
 	mutex_lock(&local->mtx);
-	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
+	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
+	     local->sched_scanning,
 		"%s called with hardware scan in progress\n", __func__);
 	mutex_unlock(&local->mtx);
 
@@ -830,6 +831,9 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	if (!local->ops->remain_on_channel)
 		local->hw.wiphy->max_remain_on_channel_duration = 5000;
 
+	if (local->ops->sched_scan_start)
+		local->hw.wiphy->flags |= WIPHY_FLAG_SUPPORTS_SCHED_SCAN;
+
 	result = wiphy_register(local->hw.wiphy);
 	if (result < 0)
 		goto fail_wiphy_register;
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 13a6697..95aab81 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -404,11 +404,13 @@ ieee80211_rx_h_passive_scan(struct ieee80211_rx_data *rx)
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 	struct sk_buff *skb = rx->skb;
 
-	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN)))
+	if (likely(!(status->rx_flags & IEEE80211_RX_IN_SCAN) &&
+		   !local->sched_scanning))
 		return RX_CONTINUE;
 
 	if (test_bit(SCAN_HW_SCANNING, &local->scanning) ||
-	    test_bit(SCAN_SW_SCANNING, &local->scanning))
+	    test_bit(SCAN_SW_SCANNING, &local->scanning) ||
+	    local->sched_scanning)
 		return ieee80211_scan_rx(rx->sdata, skb);
 
 	/* scanning finished during invoking of handlers */
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 8acce72..ea44a8e 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -15,6 +15,7 @@
 #include <linux/if_arp.h>
 #include <linux/rtnetlink.h>
 #include <linux/pm_qos_params.h>
+#include <linux/slab.h>
 #include <net/sch_generic.h>
 #include <linux/slab.h>
 #include <net/mac80211.h>
@@ -850,3 +851,101 @@ void ieee80211_scan_cancel(struct ieee80211_local *local)
 	}
 	mutex_unlock(&local->mtx);
 }
+
+int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata,
+				       struct cfg80211_sched_scan_request *req)
+{
+	struct ieee80211_local *local = sdata->local;
+	int ret, i;
+
+	mutex_lock(&sdata->local->mtx);
+
+	if (local->sched_scanning) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	if (!local->ops->sched_scan_start) {
+		ret = -ENOTSUPP;
+		goto out;
+	}
+
+	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
+		local->sched_scan_ies.ie[i] = kzalloc(2 +
+						      IEEE80211_MAX_SSID_LEN +
+						      local->scan_ies_len,
+						      GFP_KERNEL);
+		if (!local->sched_scan_ies.ie[i]) {
+			ret = -ENOMEM;
+			goto out_free;
+		}
+
+		local->sched_scan_ies.len[i] =
+			ieee80211_build_preq_ies(local,
+						 local->sched_scan_ies.ie[i],
+						 req->ie, req->ie_len, i,
+						 (u32) -1, 0);
+	}
+
+	ret = drv_sched_scan_start(local, sdata, req,
+				   &local->sched_scan_ies);
+	if (ret == 0) {
+		local->sched_scanning = true;
+		goto out;
+	}
+
+out_free:
+	while (i > 0)
+		kfree(local->sched_scan_ies.ie[--i]);
+out:
+	mutex_unlock(&sdata->local->mtx);
+	return ret;
+}
+
+int ieee80211_request_sched_scan_stop(struct ieee80211_sub_if_data *sdata,
+				      bool driver_initiated)
+{
+	struct ieee80211_local *local = sdata->local;
+	int ret = 0, i;
+
+	mutex_lock(&sdata->local->mtx);
+
+	if (!local->ops->sched_scan_stop) {
+		ret = -ENOTSUPP;
+		goto out;
+	}
+
+	if (local->sched_scanning) {
+		for (i = 0; i < IEEE80211_NUM_BANDS; i++)
+			kfree(local->sched_scan_ies.ie[i]);
+
+		if (!driver_initiated)
+			drv_sched_scan_stop(local, sdata);
+		local->sched_scanning = false;
+	}
+
+out:
+	mutex_unlock(&sdata->local->mtx);
+
+	return ret;
+}
+
+void ieee80211_sched_scan_results(struct ieee80211_hw *hw)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	trace_api_sched_scan_results(local);
+
+	cfg80211_sched_scan_results(hw->wiphy);
+}
+EXPORT_SYMBOL(ieee80211_sched_scan_results);
+
+void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	trace_api_sched_scan_stopped(local);
+
+	cfg80211_sched_scan_stopped(hw->wiphy);
+}
+EXPORT_SYMBOL(ieee80211_sched_scan_stopped);
-- 
1.7.1

[PATCH v3 3/3] cfg80211/nl80211: add interval attribute for scheduled scans

[Luciano Coelho]

Introduce NL80211_ATTR_SCHED_SCAN_INTERVAL as a required attribute for
NL80211_CMD_START_SCHED_SCAN.  This value informs the driver at which
intervals the scheduled scan cycles should be executed.

Signed-off-by: Luciano Coelho <coelho@ti.com>
---
 include/linux/nl80211.h |   25 ++++++++++++++++---------
 include/net/cfg80211.h  |    2 ++
 net/wireless/nl80211.c  |   10 ++++++++++
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index 8f02fac..5912529 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -203,15 +203,17 @@
  * @NL80211_CMD_SCAN_ABORTED: scan was aborted, for unspecified reasons,
  *	partial scan results may be available
  *
- * @NL80211_CMD_START_SCHED_SCAN: start a scheduled scan.  Like with normal
- *	scans, if SSIDs (%NL80211_ATTR_SCAN_SSIDS) are passed, they are used
- *	in the probe requests.  For broadcast, a broadcast SSID must be
- *	passed (ie. an empty string).  If no SSID is passed, no probe
- *	requests are sent and a passive scan is performed.
- *	%NL80211_ATTR_SCAN_FREQUENCIES, 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.
+ * @NL80211_CMD_START_SCHED_SCAN: start a scheduled scan at certain
+ *	intervals, as specified by %NL80211_ATTR_SCHED_SCAN_INTERVAL.
+ *	Like with normal scans, if SSIDs (%NL80211_ATTR_SCAN_SSIDS)
+ *	are passed, they are used in the probe requests.  For
+ *	broadcast, a broadcast SSID must be passed (ie. an empty
+ *	string).  If no SSID is passed, no probe requests are sent and
+ *	a passive scan is performed.  %NL80211_ATTR_SCAN_FREQUENCIES,
+ *	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.
  * @NL80211_CMD_STOP_SCHED_SCAN: stop a scheduled scan
  * @NL80211_CMD_SCHED_SCAN_RESULTS: indicates that there are scheduled scan
  *	results available.
@@ -945,6 +947,9 @@ enum nl80211_commands {
  *	indicate which WoW triggers should be enabled. This is also
  *	used by %NL80211_CMD_GET_WOWLAN to get the currently enabled WoWLAN
  *	triggers.
+
+ * @NL80211_ATTR_SCHED_SCAN_INTERVAL: Interval between scheduled scan
+ *	cycles, in msecs.
  *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -1138,6 +1143,8 @@ enum nl80211_attrs {
 	NL80211_ATTR_WOWLAN_TRIGGERS,
 	NL80211_ATTR_WOWLAN_TRIGGERS_SUPPORTED,
 
+	NL80211_ATTR_SCHED_SCAN_INTERVAL,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index d9b92c4..b18327f 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -798,6 +798,7 @@ struct cfg80211_scan_request {
  * @ssids: SSIDs to scan for (passed in the probe_reqs in active scans)
  * @n_ssids: number of SSIDs
  * @n_channels: total number of channels to scan
+ * @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
  * @wiphy: the wiphy this was for
@@ -808,6 +809,7 @@ struct cfg80211_sched_scan_request {
 	struct cfg80211_ssid *ssids;
 	int n_ssids;
 	u32 n_channels;
+	u32 interval;
 	const u8 *ie;
 	size_t ie_len;
 
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0c32faf..b95436a 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -174,6 +174,7 @@ static const struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] = {
 	[NL80211_ATTR_OFFCHANNEL_TX_OK] = { .type = NLA_FLAG },
 	[NL80211_ATTR_KEY_DEFAULT_TYPES] = { .type = NLA_NESTED },
 	[NL80211_ATTR_WOWLAN_TRIGGERS] = { .type = NLA_NESTED },
+	[NL80211_ATTR_SCHED_SCAN_INTERVAL] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -3362,6 +3363,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 	struct nlattr *attr;
 	struct wiphy *wiphy;
 	int err, tmp, n_ssids = 0, n_channels, i;
+	u32 interval;
 	enum ieee80211_band band;
 	size_t ie_len;
 
@@ -3375,6 +3377,13 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 	if (rdev->sched_scan_req)
 		return -EINPROGRESS;
 
+	if (!info->attrs[NL80211_ATTR_SCHED_SCAN_INTERVAL])
+		return -EINVAL;
+
+	interval = nla_get_u32(info->attrs[NL80211_ATTR_SCHED_SCAN_INTERVAL]);
+	if (interval == 0)
+		return -EINVAL;
+
 	wiphy = &rdev->wiphy;
 
 	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {
@@ -3497,6 +3506,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 
 	request->dev = dev;
 	request->wiphy = &rdev->wiphy;
+	request->interval = interval;
 
 	err = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
 	if (!err) {
-- 
1.7.1