[PATCH v4 3/3] Bluetooth: Add MGMT Load Connection Subrate command

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Add MGMT_OP_LOAD_CONN_SUBRATE (0x005C) command to load per-device
connection subrate parameters when the SCI feature is supported.

Add MGMT_EV_CONN_SUBRATE (0x0033) event to notify userspace when
connection rate changes occur via the LE Connection Rate Change HCI
event.

Add subrate fields (subrate_min, subrate_max, max_latency, cont_num)
to struct hci_conn_params to store the loaded subrate parameters, and
the corresponding le_rate_* fields to struct hci_conn to track the
parameters currently in use.

When a single entry is loaded for an already-connected central, or on
connection completion, the LE Connection Rate Request procedure is
initiated to apply the parameters.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_core.h |  10 +++
 include/net/bluetooth/hci_sync.h |   1 +
 include/net/bluetooth/mgmt.h     |  28 +++++++
 net/bluetooth/hci_event.c        |  32 ++++++--
 net/bluetooth/hci_sync.c         |  69 ++++++++++++++++
 net/bluetooth/mgmt.c             | 132 +++++++++++++++++++++++++++++++
 6 files changed, 264 insertions(+), 8 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index d1f37097925d..b7e032a824e1 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -816,6 +816,14 @@ struct hci_conn_params {
 	u16 conn_latency;
 	u16 supervision_timeout;
 
+	u16 rate_min_interval;
+	u16 rate_max_interval;
+	u16 subrate_min;
+	u16 subrate_max;
+	u16 max_latency;
+	u16 cont_num;
+	u16 rate_supv_timeout;
+
 	enum {
 		HCI_AUTO_CONN_DISABLED,
 		HCI_AUTO_CONN_REPORT,
@@ -2503,6 +2511,8 @@ void mgmt_advertising_removed(struct sock *sk, struct hci_dev *hdev,
 int mgmt_phy_configuration_changed(struct hci_dev *hdev, struct sock *skip);
 void mgmt_adv_monitor_device_lost(struct hci_dev *hdev, u16 handle,
 				  bdaddr_t *bdaddr, u8 addr_type);
+void mgmt_conn_subrate_notify(struct hci_dev *hdev, struct hci_conn *conn,
+			      u8 status);
 
 int hci_abort_conn(struct hci_conn *conn, u8 reason);
 void hci_le_conn_update(struct hci_conn *conn, u16 min, u16 max, u16 latency,
diff --git a/include/net/bluetooth/hci_sync.h b/include/net/bluetooth/hci_sync.h
index 0756d6fe77d4..a6579a868678 100644
--- a/include/net/bluetooth/hci_sync.h
+++ b/include/net/bluetooth/hci_sync.h
@@ -183,6 +183,7 @@ int hci_connect_le_sync(struct hci_dev *hdev, struct hci_conn *conn);
 int hci_cancel_connect_sync(struct hci_dev *hdev, struct hci_conn *conn);
 int hci_le_conn_update_sync(struct hci_dev *hdev, struct hci_conn *conn,
 			    struct hci_conn_params *params);
+int hci_le_conn_rate_request(struct hci_dev *hdev, struct hci_conn *conn);
 
 int hci_connect_pa_sync(struct hci_dev *hdev, struct hci_conn *conn);
 int hci_connect_big_sync(struct hci_dev *hdev, struct hci_conn *conn);
diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index b285441db55b..1e22eab1081c 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -894,6 +894,23 @@ struct mgmt_cp_hci_cmd_sync {
 } __packed;
 #define MGMT_HCI_CMD_SYNC_SIZE		6
 
+#define MGMT_OP_LOAD_CONN_SUBRATE	0x005C
+struct mgmt_conn_subrate {
+	struct mgmt_addr_info addr;
+	__le16 min_interval;
+	__le16 max_interval;
+	__le16 subrate_min;
+	__le16 subrate_max;
+	__le16 max_latency;
+	__le16 cont_num;
+	__le16 supv_timeout;
+} __packed;
+struct mgmt_cp_load_conn_subrate {
+	__le16 param_count;
+	struct mgmt_conn_subrate params[] __counted_by_le(param_count);
+} __packed;
+#define MGMT_LOAD_CONN_SUBRATE_SIZE	2
+
 #define MGMT_EV_CMD_COMPLETE		0x0001
 struct mgmt_ev_cmd_complete {
 	__le16	opcode;
@@ -1193,3 +1210,14 @@ struct mgmt_ev_mesh_device_found {
 struct mgmt_ev_mesh_pkt_cmplt {
 	__u8	handle;
 } __packed;
+
+#define MGMT_EV_CONN_SUBRATE			0x0033
+struct mgmt_ev_conn_subrate {
+	struct mgmt_addr_info addr;
+	__u8	status;
+	__le16	interval;
+	__le16	subrate;
+	__le16	latency;
+	__le16	cont_num;
+	__le16	supv_timeout;
+} __packed;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 5732b282f6df..9d8b0ce63c6f 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -5903,6 +5903,17 @@ static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
 		}
 	}
 
+	/* If we are central and have subrate parameters stored, queue a
+	 * connection rate request to apply them.
+	 */
+	if (conn->role == HCI_ROLE_MASTER && le_sci_capable(hdev)) {
+		struct hci_conn_params *p;
+
+		p = hci_conn_params_lookup(hdev, &conn->dst, conn->dst_type);
+		if (p && p->subrate_max)
+			hci_le_conn_rate_request(hdev, conn);
+	}
+
 unlock:
 	hci_update_passive_scan(hdev);
 	hci_dev_unlock(hdev);
@@ -7407,18 +7418,23 @@ static void hci_le_conn_rate_change_evt(struct hci_dev *hdev, void *data,
 
 	bt_dev_dbg(hdev, "status 0x%2.2x", ev->status);
 
-	if (ev->status)
-		return;
-
 	hci_dev_lock(hdev);
 
 	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(ev->handle));
 	if (conn) {
-		conn->le_rate_interval = le16_to_cpu(ev->interval);
-		conn->le_subrate = le16_to_cpu(ev->subrate);
-		conn->le_rate_latency = le16_to_cpu(ev->latency);
-		conn->le_cont_num = le16_to_cpu(ev->cont_number);
-		conn->le_rate_supv_timeout = le16_to_cpu(ev->supv_timeout);
+		/* Only update the stored rate parameters on success; on
+		 * failure the values in the event are not valid. Userspace is
+		 * notified either way.
+		 */
+		if (!ev->status) {
+			conn->le_rate_interval = le16_to_cpu(ev->interval);
+			conn->le_subrate = le16_to_cpu(ev->subrate);
+			conn->le_rate_latency = le16_to_cpu(ev->latency);
+			conn->le_cont_num = le16_to_cpu(ev->cont_number);
+			conn->le_rate_supv_timeout =
+				le16_to_cpu(ev->supv_timeout);
+		}
+		mgmt_conn_subrate_notify(hdev, conn, ev->status);
 	}
 
 	hci_dev_unlock(hdev);
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 868ab1f1daf7..701edef7d08b 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -7282,6 +7282,75 @@ int hci_le_conn_update_sync(struct hci_dev *hdev, struct hci_conn *conn,
 				     sizeof(cp), &cp, HCI_CMD_TIMEOUT);
 }
 
+static int hci_le_conn_rate_request_sync(struct hci_dev *hdev, void *data)
+{
+	struct hci_conn *conn = data;
+	struct hci_conn_params *params;
+	struct hci_cp_le_conn_rate cp;
+
+	hci_dev_lock(hdev);
+
+	/* The request was queued asynchronously so re-validate the connection
+	 * and its parameters under hdev->lock. The connection may have been
+	 * torn down, or may not have a valid handle yet (still connecting),
+	 * and the parameters may have been removed in the meantime (e.g. by
+	 * Load Connection Parameters). Snapshot the rate values so the
+	 * blocking command below can run without holding hdev->lock.
+	 */
+	if (!hci_conn_valid(hdev, conn) ||
+	    HCI_CONN_HANDLE_UNSET(conn->handle)) {
+		hci_dev_unlock(hdev);
+		return -ECANCELED;
+	}
+
+	params = hci_conn_params_lookup(hdev, &conn->dst, conn->dst_type);
+	if (!params) {
+		hci_dev_unlock(hdev);
+		return -ECANCELED;
+	}
+
+	memset(&cp, 0, sizeof(cp));
+	cp.handle	= cpu_to_le16(conn->handle);
+	cp.interval_min	= cpu_to_le16(params->rate_min_interval);
+	cp.interval_max	= cpu_to_le16(params->rate_max_interval);
+	cp.subrate_min	= cpu_to_le16(params->subrate_min);
+	cp.subrate_max	= cpu_to_le16(params->subrate_max);
+	cp.max_latency	= cpu_to_le16(params->max_latency);
+	cp.cont_num	= cpu_to_le16(params->cont_num);
+	cp.supv_timeout	= cpu_to_le16(params->rate_supv_timeout);
+	cp.min_ce_len	= cpu_to_le16(0x0000);
+	cp.max_ce_len	= cpu_to_le16(0x0000);
+
+	hci_dev_unlock(hdev);
+
+	return __hci_cmd_sync_status(hdev, HCI_OP_LE_CONN_RATE,
+				     sizeof(cp), &cp, HCI_CMD_TIMEOUT);
+}
+
+static void hci_le_conn_rate_request_destroy(struct hci_dev *hdev, void *data,
+					     int err)
+{
+	struct hci_conn *conn = data;
+
+	hci_conn_put(conn);
+}
+
+int hci_le_conn_rate_request(struct hci_dev *hdev, struct hci_conn *conn)
+{
+	int err;
+
+	/* Hold a reference to the connection so it cannot be freed while the
+	 * request is pending or running on the cmd_sync worker.
+	 */
+	err = hci_cmd_sync_queue(hdev, hci_le_conn_rate_request_sync,
+				 hci_conn_get(conn),
+				 hci_le_conn_rate_request_destroy);
+	if (err < 0)
+		hci_conn_put(conn);
+
+	return err;
+}
+
 static void create_pa_complete(struct hci_dev *hdev, void *data, int err)
 {
 	struct hci_conn *conn = data;
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 58f01fbfcf71..e376759ccf00 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -8160,6 +8160,119 @@ static int load_conn_param(struct sock *sk, struct hci_dev *hdev, void *data,
 				 NULL, 0);
 }
 
+static int load_conn_subrate(struct sock *sk, struct hci_dev *hdev, void *data,
+			     u16 len)
+{
+	struct mgmt_cp_load_conn_subrate *cp = data;
+	const u16 max_param_count = ((U16_MAX - sizeof(*cp)) /
+				     sizeof(struct mgmt_conn_subrate));
+	u16 param_count, expected_len;
+	int i;
+
+	if (!lmp_le_capable(hdev) || !le_sci_capable(hdev))
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_LOAD_CONN_SUBRATE,
+				       MGMT_STATUS_NOT_SUPPORTED);
+
+	param_count = __le16_to_cpu(cp->param_count);
+	if (param_count > max_param_count) {
+		bt_dev_err(hdev, "load_conn_subrate: too big param_count value %u",
+			   param_count);
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_LOAD_CONN_SUBRATE,
+				       MGMT_STATUS_INVALID_PARAMS);
+	}
+
+	expected_len = struct_size(cp, params, param_count);
+	if (expected_len != len) {
+		bt_dev_err(hdev, "load_conn_subrate: expected %u bytes, got %u bytes",
+			   expected_len, len);
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_LOAD_CONN_SUBRATE,
+				       MGMT_STATUS_INVALID_PARAMS);
+	}
+
+	bt_dev_dbg(hdev, "param_count %u", param_count);
+
+	hci_dev_lock(hdev);
+
+	for (i = 0; i < param_count; i++) {
+		struct mgmt_conn_subrate *param = &cp->params[i];
+		struct hci_conn_params *hci_param;
+		u16 min, max, subrate_min, subrate_max;
+		u16 max_latency, cont_num, supv_timeout;
+		u8 addr_type;
+
+		bt_dev_dbg(hdev, "Adding subrate %pMR (type %u)",
+			   &param->addr.bdaddr, param->addr.type);
+
+		if (param->addr.type == BDADDR_LE_PUBLIC) {
+			addr_type = ADDR_LE_DEV_PUBLIC;
+		} else if (param->addr.type == BDADDR_LE_RANDOM) {
+			addr_type = ADDR_LE_DEV_RANDOM;
+		} else {
+			bt_dev_err(hdev, "ignoring invalid connection subrate parameters");
+			continue;
+		}
+
+		min = le16_to_cpu(param->min_interval);
+		max = le16_to_cpu(param->max_interval);
+		subrate_min = le16_to_cpu(param->subrate_min);
+		subrate_max = le16_to_cpu(param->subrate_max);
+		max_latency = le16_to_cpu(param->max_latency);
+		cont_num = le16_to_cpu(param->cont_num);
+		supv_timeout = le16_to_cpu(param->supv_timeout);
+
+		/* Validate the parameters before storing them. Reject
+		 * logically inconsistent values instead of forwarding them to
+		 * the controller.
+		 */
+		if (min > max || subrate_min > subrate_max ||
+		    subrate_min < 1 || supv_timeout < 1) {
+			bt_dev_err(hdev, "ignoring invalid connection subrate parameters");
+			continue;
+		}
+
+		hci_param = hci_conn_params_add(hdev, &param->addr.bdaddr,
+						addr_type);
+		if (!hci_param) {
+			bt_dev_err(hdev, "failed to add connection parameters");
+			continue;
+		}
+
+		hci_param->rate_min_interval = min;
+		hci_param->rate_max_interval = max;
+		hci_param->subrate_min = subrate_min;
+		hci_param->subrate_max = subrate_max;
+		hci_param->max_latency = max_latency;
+		hci_param->cont_num = cont_num;
+		hci_param->rate_supv_timeout = supv_timeout;
+
+		/* If the device is connected as central check if the
+		 * connection rate parameters need to be updated.
+		 */
+		if (!i && param_count == 1) {
+			struct hci_conn *conn;
+
+			conn = hci_conn_hash_lookup_le(hdev,
+						       &hci_param->addr,
+						       addr_type);
+			if (conn && conn->state == BT_CONNECTED &&
+			    conn->role == HCI_ROLE_MASTER &&
+			    (conn->le_rate_interval < min ||
+			     conn->le_rate_interval > max ||
+			     conn->le_subrate < subrate_min ||
+			     conn->le_subrate > subrate_max ||
+			     conn->le_rate_latency != max_latency ||
+			     conn->le_cont_num != cont_num ||
+			     conn->le_rate_supv_timeout != supv_timeout))
+				hci_le_conn_rate_request(hdev, conn);
+		}
+	}
+
+	hci_dev_unlock(hdev);
+
+	return mgmt_cmd_complete(sk, hdev->id, MGMT_OP_LOAD_CONN_SUBRATE, 0,
+				 NULL, 0);
+}
+
 static int set_external_config(struct sock *sk, struct hci_dev *hdev,
 			       void *data, u16 len)
 {
@@ -9577,6 +9690,8 @@ static const struct hci_mgmt_handler mgmt_handlers[] = {
 						HCI_MGMT_VAR_LEN },
 	{ mesh_send_cancel,        MGMT_MESH_SEND_CANCEL_SIZE },
 	{ mgmt_hci_cmd_sync,       MGMT_HCI_CMD_SYNC_SIZE, HCI_MGMT_VAR_LEN },
+	{ load_conn_subrate,       MGMT_LOAD_CONN_SUBRATE_SIZE,
+						HCI_MGMT_VAR_LEN },
 };
 
 void mgmt_index_added(struct hci_dev *hdev)
@@ -10725,6 +10840,23 @@ int mgmt_init(void)
 	return hci_mgmt_chan_register(&chan);
 }
 
+void mgmt_conn_subrate_notify(struct hci_dev *hdev, struct hci_conn *conn,
+			      u8 status)
+{
+	struct mgmt_ev_conn_subrate ev;
+
+	bacpy(&ev.addr.bdaddr, &conn->dst);
+	ev.addr.type = link_to_bdaddr(conn->type, conn->dst_type);
+	ev.status = mgmt_status(status);
+	ev.interval = cpu_to_le16(conn->le_rate_interval);
+	ev.subrate = cpu_to_le16(conn->le_subrate);
+	ev.latency = cpu_to_le16(conn->le_rate_latency);
+	ev.cont_num = cpu_to_le16(conn->le_cont_num);
+	ev.supv_timeout = cpu_to_le16(conn->le_rate_supv_timeout);
+
+	mgmt_event(MGMT_EV_CONN_SUBRATE, hdev, &ev, sizeof(ev), NULL);
+}
+
 void mgmt_exit(void)
 {
 	hci_mgmt_chan_unregister(&chan);
-- 
2.54.0