cfg80211/nl80211: add support for scheduled scans

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>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 342 insertions, 1 deletions

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 95dd583..4fac370 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -761,6 +761,8 @@ 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
 
@@ -3357,6 +3359,179 @@ 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,
@@ -5327,6 +5502,22 @@ 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,
@@ -5652,6 +5843,28 @@ 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)
 {
@@ -5709,6 +5922,43 @@ 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 62e542a..65dfae3 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;