ieee802154: Add support for user scanning requests

The ieee802154 layer should be able to scan a set of channels in order
to look for beacons advertizing PANs. Supporting this involves adding
two user commands: triggering scans and aborting scans. The user should
also be notified when a new beacon is received and also upon scan
termination.

A scan request structure is created to list the requirements and to be
accessed asynchronously when changing channels or receiving beacons.

Mac layers may now implement the ->trigger_scan() and ->abort_scan()
hooks.

Co-developed-by: David Girault <david.girault@qorvo.com>
Signed-off-by: David Girault <david.girault@qorvo.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20230103165644.432209-2-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

4 files changed, 291 insertions, 0 deletions

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 248ad5e46969..11aa693af449 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -221,6 +221,13 @@ static const struct nla_policy nl802154_policy[NL802154_ATTR_MAX+1] = {
 
 	[NL802154_ATTR_COORDINATOR] = { .type = NLA_NESTED },
 
+	[NL802154_ATTR_SCAN_TYPE] = { .type = NLA_U8 },
+	[NL802154_ATTR_SCAN_CHANNELS] = { .type = NLA_U32 },
+	[NL802154_ATTR_SCAN_PREAMBLE_CODES] = { .type = NLA_U64 },
+	[NL802154_ATTR_SCAN_MEAN_PRF] = { .type = NLA_U8 },
+	[NL802154_ATTR_SCAN_DURATION] = { .type = NLA_U8 },
+	[NL802154_ATTR_SCAN_DONE_REASON] = { .type = NLA_U8 },
+
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	[NL802154_ATTR_SEC_ENABLED] = { .type = NLA_U8, },
 	[NL802154_ATTR_SEC_OUT_LEVEL] = { .type = NLA_U32, },
@@ -1384,6 +1391,203 @@ int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
 }
 EXPORT_SYMBOL_GPL(nl802154_scan_event);
 
+static int nl802154_trigger_scan(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_scan_request *request;
+	u8 type;
+	int err;
+
+	/* Monitors are not allowed to perform scans */
+	if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
+		return -EPERM;
+
+	request = kzalloc(sizeof(*request), GFP_KERNEL);
+	if (!request)
+		return -ENOMEM;
+
+	request->wpan_dev = wpan_dev;
+	request->wpan_phy = wpan_phy;
+
+	type = nla_get_u8(info->attrs[NL802154_ATTR_SCAN_TYPE]);
+	switch (type) {
+	case NL802154_SCAN_PASSIVE:
+		request->type = type;
+		break;
+	default:
+		pr_err("Unsupported scan type: %d\n", type);
+		err = -EINVAL;
+		goto free_request;
+	}
+
+	if (info->attrs[NL802154_ATTR_PAGE]) {
+		request->page = nla_get_u8(info->attrs[NL802154_ATTR_PAGE]);
+		if (request->page > IEEE802154_MAX_PAGE) {
+			pr_err("Invalid page %d > %d\n",
+			       request->page, IEEE802154_MAX_PAGE);
+			err = -EINVAL;
+			goto free_request;
+		}
+	} else {
+		/* Use current page by default */
+		request->page = wpan_phy->current_page;
+	}
+
+	if (info->attrs[NL802154_ATTR_SCAN_CHANNELS]) {
+		request->channels = nla_get_u32(info->attrs[NL802154_ATTR_SCAN_CHANNELS]);
+		if (request->channels >= BIT(IEEE802154_MAX_CHANNEL + 1)) {
+			pr_err("Invalid channels bitfield %x ≥ %lx\n",
+			       request->channels,
+			       BIT(IEEE802154_MAX_CHANNEL + 1));
+			err = -EINVAL;
+			goto free_request;
+		}
+	} else {
+		/* Scan all supported channels by default */
+		request->channels = wpan_phy->supported.channels[request->page];
+	}
+
+	if (info->attrs[NL802154_ATTR_SCAN_PREAMBLE_CODES] ||
+	    info->attrs[NL802154_ATTR_SCAN_MEAN_PRF]) {
+		pr_err("Preamble codes and mean PRF not supported yet\n");
+		err = -EINVAL;
+		goto free_request;
+	}
+
+	if (info->attrs[NL802154_ATTR_SCAN_DURATION]) {
+		request->duration = nla_get_u8(info->attrs[NL802154_ATTR_SCAN_DURATION]);
+		if (request->duration > IEEE802154_MAX_SCAN_DURATION) {
+			pr_err("Duration is out of range\n");
+			err = -EINVAL;
+			goto free_request;
+		}
+	} else {
+		/* Use maximum duration order by default */
+		request->duration = IEEE802154_MAX_SCAN_DURATION;
+	}
+
+	if (wpan_dev->netdev)
+		dev_hold(wpan_dev->netdev);
+
+	err = rdev_trigger_scan(rdev, request);
+	if (err) {
+		pr_err("Failure starting scanning (%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;
+}
+
+static int nl802154_prep_scan_msg(struct sk_buff *msg,
+				  struct cfg802154_registered_device *rdev,
+				  struct wpan_dev *wpan_dev, u32 portid,
+				  u32 seq, int flags, u8 cmd, u8 arg)
+{
+	void *hdr;
+
+	hdr = nl802154hdr_put(msg, portid, seq, flags, cmd);
+	if (!hdr)
+		return -ENOBUFS;
+
+	if (nla_put_u32(msg, NL802154_ATTR_WPAN_PHY, rdev->wpan_phy_idx))
+		goto nla_put_failure;
+
+	if (wpan_dev->netdev &&
+	    nla_put_u32(msg, NL802154_ATTR_IFINDEX, wpan_dev->netdev->ifindex))
+		goto nla_put_failure;
+
+	if (nla_put_u64_64bit(msg, NL802154_ATTR_WPAN_DEV,
+			      wpan_dev_id(wpan_dev), NL802154_ATTR_PAD))
+		goto nla_put_failure;
+
+	if (cmd == NL802154_CMD_SCAN_DONE &&
+	    nla_put_u8(msg, NL802154_ATTR_SCAN_DONE_REASON, arg))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+
+	return -EMSGSIZE;
+}
+
+static int nl802154_send_scan_msg(struct cfg802154_registered_device *rdev,
+				  struct wpan_dev *wpan_dev, u8 cmd, u8 arg)
+{
+	struct sk_buff *msg;
+	int ret;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	ret = nl802154_prep_scan_msg(msg, rdev, wpan_dev, 0, 0, 0, cmd, arg);
+	if (ret < 0) {
+		nlmsg_free(msg);
+		return ret;
+	}
+
+	return genlmsg_multicast_netns(&nl802154_fam,
+				       wpan_phy_net(&rdev->wpan_phy), msg, 0,
+				       NL802154_MCGRP_SCAN, GFP_KERNEL);
+}
+
+int nl802154_scan_started(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev)
+{
+	struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(wpan_phy);
+	int err;
+
+	/* Ignore errors when there are no listeners */
+	err = nl802154_send_scan_msg(rdev, wpan_dev, NL802154_CMD_TRIGGER_SCAN, 0);
+	if (err == -ESRCH)
+		err = 0;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(nl802154_scan_started);
+
+int nl802154_scan_done(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
+		       enum nl802154_scan_done_reasons reason)
+{
+	struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(wpan_phy);
+	int err;
+
+	/* Ignore errors when there are no listeners */
+	err = nl802154_send_scan_msg(rdev, wpan_dev, NL802154_CMD_SCAN_DONE, reason);
+	if (err == -ESRCH)
+		err = 0;
+
+	if (wpan_dev->netdev)
+		dev_put(wpan_dev->netdev);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(nl802154_scan_done);
+
+static int nl802154_abort_scan(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_abort_scan(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 },
@@ -2474,6 +2678,22 @@ static const struct genl_ops nl802154_ops[] = {
 		.internal_flags = NL802154_FLAG_NEED_NETDEV |
 				  NL802154_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL802154_CMD_TRIGGER_SCAN,
+		.doit = nl802154_trigger_scan,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL802154_FLAG_NEED_NETDEV |
+				  NL802154_FLAG_CHECK_NETDEV_UP |
+				  NL802154_FLAG_NEED_RTNL,
+	},
+	{
+		.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,
+	},
 #ifdef CONFIG_IEEE802154_NL802154_EXPERIMENTAL
 	{
 		.cmd = NL802154_CMD_SET_SEC_PARAMS,
diff --git a/net/ieee802154/nl802154.h b/net/ieee802154/nl802154.h
index 89b805500032..cfa7134be747 100644
--- a/net/ieee802154/nl802154.h
+++ b/net/ieee802154/nl802154.h
@@ -6,5 +6,8 @@ int nl802154_init(void);
 void nl802154_exit(void);
 int nl802154_scan_event(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev,
 			struct ieee802154_coord_desc *desc);
+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);
 
 #endif /* __IEEE802154_NL802154_H */
diff --git a/net/ieee802154/rdev-ops.h b/net/ieee802154/rdev-ops.h
index 598f5af49775..e171d74c3251 100644
--- a/net/ieee802154/rdev-ops.h
+++ b/net/ieee802154/rdev-ops.h
@@ -209,6 +209,34 @@ rdev_set_ackreq_default(struct cfg802154_registered_device *rdev,
 	return ret;
 }
 
+static inline int rdev_trigger_scan(struct cfg802154_registered_device *rdev,
+				    struct cfg802154_scan_request *request)
+{
+	int ret;
+
+	if (!rdev->ops->trigger_scan)
+		return -EOPNOTSUPP;
+
+	trace_802154_rdev_trigger_scan(&rdev->wpan_phy, request);
+	ret = rdev->ops->trigger_scan(&rdev->wpan_phy, request);
+	trace_802154_rdev_return_int(&rdev->wpan_phy, ret);
+	return ret;
+}
+
+static inline int rdev_abort_scan(struct cfg802154_registered_device *rdev,
+				  struct wpan_dev *wpan_dev)
+{
+	int ret;
+
+	if (!rdev->ops->abort_scan)
+		return -EOPNOTSUPP;
+
+	trace_802154_rdev_abort_scan(&rdev->wpan_phy, wpan_dev);
+	ret = rdev->ops->abort_scan(&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
diff --git a/net/ieee802154/trace.h b/net/ieee802154/trace.h
index 19c2e5d60e76..e5405f737ded 100644
--- a/net/ieee802154/trace.h
+++ b/net/ieee802154/trace.h
@@ -295,6 +295,46 @@ TRACE_EVENT(802154_rdev_set_ackreq_default,
 		WPAN_DEV_PR_ARG, BOOL_TO_STR(__entry->ackreq))
 );
 
+TRACE_EVENT(802154_rdev_trigger_scan,
+	TP_PROTO(struct wpan_phy *wpan_phy,
+		 struct cfg802154_scan_request *request),
+	TP_ARGS(wpan_phy, request),
+	TP_STRUCT__entry(
+		WPAN_PHY_ENTRY
+		__field(u8, page)
+		__field(u32, channels)
+		__field(u8, duration)
+	),
+	TP_fast_assign(
+		WPAN_PHY_ASSIGN;
+		__entry->page = request->page;
+		__entry->channels = request->channels;
+		__entry->duration = request->duration;
+	),
+	TP_printk(WPAN_PHY_PR_FMT ", scan, page: %d, channels: %x, duration %d",
+		  WPAN_PHY_PR_ARG, __entry->page, __entry->channels, __entry->duration)
+);
+
+DECLARE_EVENT_CLASS(802154_wdev_template,
+	TP_PROTO(struct wpan_phy *wpan_phy, struct wpan_dev *wpan_dev),
+	TP_ARGS(wpan_phy, wpan_dev),
+	TP_STRUCT__entry(
+		WPAN_PHY_ENTRY
+		WPAN_DEV_ENTRY
+	),
+	TP_fast_assign(
+		WPAN_PHY_ASSIGN;
+		WPAN_DEV_ASSIGN;
+	),
+	TP_printk(WPAN_PHY_PR_FMT ", " WPAN_DEV_PR_FMT,
+		  WPAN_PHY_PR_ARG, WPAN_DEV_PR_ARG)
+);
+
+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)
+);
+
 TRACE_EVENT(802154_rdev_return_int,
 	TP_PROTO(struct wpan_phy *wpan_phy, int ret),
 	TP_ARGS(wpan_phy, ret),