ieee802154: Add support for user beaconing requests

Parse user requests for sending beacons, start sending beacons at a
regular pace. If needed, the pace can be updated with a new request. The
process can also be interrupted at any moment.

The page and channel must be changed beforehands if needed. Interval
orders above 14 are reserved to tell a device it must answer BEACON_REQ
coming from another device as part of an active scan procedure and this
is not yet supported.

A netlink "beacon request" structure is created to list the
requirements.

Mac layers may now implement the ->send_beacons() and
->stop_beacons() hooks.

Co-developed-by: David Girault <[e-mail]>
Signed-off-by: David Girault <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Acked-by: Alexander Aring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stefan Schmidt <[e-mail]>

include/net/cfg802154.h

···
 struct wpan_phy;
 struct wpan_phy_cca;
 struct cfg802154_scan_request;
+struct cfg802154_beacon_request;
 
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 struct ieee802154_llsec_device_key;
···
 				struct cfg802154_scan_request *request);
 	int	(*abort_scan)(struct wpan_phy *wpan_phy,
 			      struct wpan_dev *wpan_dev);
+	int	(*send_beacons)(struct wpan_phy *wpan_phy,
+				struct cfg802154_beacon_request *request);
+	int	(*stop_beacons)(struct wpan_phy *wpan_phy,
+				struct wpan_dev *wpan_dev);
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	void	(*get_llsec_table)(struct wpan_phy *wpan_phy,
 				   struct wpan_dev *wpan_dev,
···
 	u8 page;
 	u32 channels;
 	u8 duration;
+	struct wpan_dev *wpan_dev;
+	struct wpan_phy *wpan_phy;
+};
+
+/**
+ * struct cfg802154_beacon_request - Beacon request descriptor
+ *
+ * @interval: interval n between sendings, in multiple order of the super frame
+ *            duration: aBaseSuperframeDuration * (2^n) unless the interval
+ *            order is greater or equal to 15, in this case beacons won't be
+ *            passively sent out at a fixed rate but instead inform the device
+ *            that it should answer beacon requests as part of active scan
+ *            procedures
+ * @wpan_dev: the concerned wpan device
+ * @wpan_phy: the wpan phy this was for
+ */
+struct cfg802154_beacon_request {
+	u8 interval;
 	struct wpan_dev *wpan_dev;
 	struct wpan_phy *wpan_phy;
 };

include/net/nl802154.h

···
 	NL802154_CMD_TRIGGER_SCAN,
 	NL802154_CMD_ABORT_SCAN,
 	NL802154_CMD_SCAN_DONE,
+	NL802154_CMD_SEND_BEACONS,
+	NL802154_CMD_STOP_BEACONS,
 
 	/* add new commands above here */
 
···
 	NL802154_ATTR_SCAN_MEAN_PRF,
 	NL802154_ATTR_SCAN_DURATION,
 	NL802154_ATTR_SCAN_DONE_REASON,
+	NL802154_ATTR_BEACON_INTERVAL,
 
 	/* add attributes here, update the policy in nl802154.c */
 

net/ieee802154/nl802154.c

···
 	[NL802154_ATTR_SCAN_MEAN_PRF] = { .type = NLA_U8 },
 	[NL802154_ATTR_SCAN_DURATION] = { .type = NLA_U8 },
 	[NL802154_ATTR_SCAN_DONE_REASON] = { .type = NLA_U8 },
+	[NL802154_ATTR_BEACON_INTERVAL] = { .type = NLA_U8 },
 
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },
···
 	return rdev_abort_scan(rdev, wpan_dev);
 }
 
+static int
+nl802154_send_beacons(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg802154_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
+	struct wpan_phy *wpan_phy = &rdev->wpan_phy;
+	struct cfg802154_beacon_request *request;
+	int err;
+
+	/* Only coordinators can send beacons */
+	if (wpan_dev->iftype != NL802154_IFTYPE_COORD)
+		return -EOPNOTSUPP;
+
+	if (wpan_dev->pan_id == cpu_to_le16(IEEE802154_PANID_BROADCAST)) {
+		pr_err("Device is not part of any PAN\n");
+		return -EPERM;
+	}
+
+	request = kzalloc(sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->wpan_dev = wpan_dev;
+	request->wpan_phy = wpan_phy;
+
+	if (info->attrs[NL802154_ATTR_BEACON_INTERVAL]) {
+		request->interval = nla_get_u8(info->attrs[NL802154_ATTR_BEACON_INTERVAL]);
+		if (request->interval > IEEE802154_MAX_SCAN_DURATION) {
+			pr_err("Interval is out of range\n");
+			err = -EINVAL;
+			goto free_request;
+		}
+	} else {
+		/* Use maximum duration order by default */
+		request->interval = IEEE802154_MAX_SCAN_DURATION;
+	}
+
+	if (wpan_dev->netdev)
+		dev_hold(wpan_dev->netdev);
+
+	err = rdev_send_beacons(rdev, request);
+	if (err) {
+		pr_err("Failure starting sending beacons (%d)\n", err);
+		goto free_device;
+	}
+
+	return 0;
+
+free_device:
+	if (wpan_dev->netdev)
+		dev_put(wpan_dev->netdev);
+free_request:
+	kfree(request);
+
+	return err;
+}
+
+void nl802154_beaconing_done(struct wpan_dev *wpan_dev)
+{
+	if (wpan_dev->netdev)
+		dev_put(wpan_dev->netdev);
+}
+EXPORT_SYMBOL_GPL(nl802154_beaconing_done);
+
+static int
+nl802154_stop_beacons(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg802154_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
+
+	/* Resources are released in the notification helper above */
+	return rdev_stop_beacons(rdev, wpan_dev);
+}
+
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 static const struct nla_policy nl802154_dev_addr_policy[NL802154_DEV_ADDR_ATTR_MAX + 1] = {
 	[NL802154_DEV_ADDR_ATTR_PAN_ID] = { .type = NLA_U16 },
···
 	{
 		.cmd = NL802154_CMD_ABORT_SCAN,
 		.doit = nl802154_abort_scan,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL802154_FLAG_NEED_NETDEV |
+				  NL802154_FLAG_CHECK_NETDEV_UP |
+				  NL802154_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL802154_CMD_SEND_BEACONS,
+		.doit = nl802154_send_beacons,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL802154_FLAG_NEED_NETDEV |
+				  NL802154_FLAG_CHECK_NETDEV_UP |
+				  NL802154_FLAG_NEED_RTNL,
+	},
+	{
+		.cmd = NL802154_CMD_STOP_BEACONS,
+		.doit = nl802154_stop_beacons,
 		.flags = GENL_ADMIN_PERM,
 		.internal_flags = NL802154_FLAG_NEED_NETDEV |
 				  NL802154_FLAG_CHECK_NETDEV_UP |

net/ieee802154/nl802154.h

···
 int nl802154_scan_started(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev);
 int nl802154_scan_done(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
 		       enum nl802154_scan_done_reasons reason);
+void nl802154_beaconing_done(struct wpan_dev *wpan_dev);
 
 #endif /* __IEEE802154_NL802154_H */

net/ieee802154/rdev-ops.h

···
 	return ret;
 }
 
+static inline int rdev_send_beacons(struct cfg802154_registered_device *rdev,
+				    struct cfg802154_beacon_request *request)
+{
+	int ret;
+
+	if (!rdev->ops->send_beacons)
+		return -EOPNOTSUPP;
+
+	trace_802154_rdev_send_beacons(&rdev->wpan_phy, request);
+	ret = rdev->ops->send_beacons(&rdev->wpan_phy, request);
+	trace_802154_rdev_return_int(&rdev->wpan_phy, ret);
+	return ret;
+}
+
+static inline int rdev_stop_beacons(struct cfg802154_registered_device *rdev,
+				    struct wpan_dev *wpan_dev)
+{
+	int ret;
+
+	if (!rdev->ops->stop_beacons)
+		return -EOPNOTSUPP;
+
+	trace_802154_rdev_stop_beacons(&rdev->wpan_phy, wpan_dev);
+	ret = rdev->ops->stop_beacons(&rdev->wpan_phy, wpan_dev);
+	trace_802154_rdev_return_int(&rdev->wpan_phy, ret);
+	return ret;
+}
+
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 /* TODO this is already a nl802154, so move into ieee802154 */
 static inline void

net/ieee802154/trace.h

···
 		  WPAN_PHY_PR_ARG, __entry->page, __entry->channels, __entry->duration)
 );
 
+TRACE_EVENT(802154_rdev_send_beacons,
+	TP_PROTO(struct wpan_phy *wpan_phy,
+		 struct cfg802154_beacon_request *request),
+	TP_ARGS(wpan_phy, request),
+	TP_STRUCT__entry(
+		WPAN_PHY_ENTRY
+		__field(u8, interval)
+	),
+	TP_fast_assign(
+		WPAN_PHY_ASSIGN;
+		__entry->interval = request->interval;
+	),
+	TP_printk(WPAN_PHY_PR_FMT ", sending beacons (interval order: %d)",
+		  WPAN_PHY_PR_ARG, __entry->interval)
+);
+
 DECLARE_EVENT_CLASS(802154_wdev_template,
 	TP_PROTO(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev),
 	TP_ARGS(wpan_phy, wpan_dev),
···
 );
 
 DEFINE_EVENT(802154_wdev_template, 802154_rdev_abort_scan,
+	TP_PROTO(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev),
+	TP_ARGS(wpan_phy, wpan_dev)
+);
+
+DEFINE_EVENT(802154_wdev_template, 802154_rdev_stop_beacons,
 	TP_PROTO(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev),
 	TP_ARGS(wpan_phy, wpan_dev)
 );