[BlueZ PATCH v1 0/3] Introduce Advertisement Monitor Device Tracking event

Hello Bt-Maintainers,

Bluetooth Advertisement Monitor API was introduced to support background
scanning and proximity detection based on the application specified RSSI
thresholds and content filters on LE advertisement packets.

To optimize the power consumption, the API offloads the content
filtering and RSSI tracking to the controller if the controller
offloading support is available. However, this monitoring is not
completely offloaded as the bluetoothd also handles RSSI thresholds and
timeouts in order to fulfill high/low thresholds/timeouts filtering with
D-bus clients.

There is further room to achieve better power optimization by supporting
the controller event HCI_VS_MSFT_LE_Monitor_Device_Event to fulfill true
monitor offloading. This is currently not supported as it was originally
desired to minimize the changes to the MGMT interface and reuse the
existing MGMT event - MGMT_EV_DEVICE_FOUND to pass advertisements to
bluetoothd and let bluetoothd handle the RSSI thresholds and timeouts in
order to fulfill the D-bus API requirements for the client.

This patch series introduces a new MGMT interface -
MGMT_EV_ADV_MONITOR_TRACKING to deliver the Monitor Device event
received from the controller to the bluetoothd.

Please let me know what you think about this or if you have any further
questions.

Thanks,
Manish.


Manish Mandlik (3):
  doc: Add Advertisement Monitor Device Tracking event
  lib: Add definition of AdvMonitor Tracking event
  adv_monitor: Receive Device Tracking event

 doc/mgmt-api.txt  | 27 ++++++++++++++++++++++++++-
 lib/mgmt.h        |  8 ++++++++
 src/adv_monitor.c | 25 +++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 1 deletion(-)

-- 
2.33.0.685.g46640cef36-goog

This patch adds the Advertisement Monitor Device Traching event. This
event indicates that the controller has stated/stopped tracking a
particular device matching one of the already added Advertisement
Monitor.

Reviewed-by: Miao-chen Chou <redacted>
Reviewed-by: Yun-Hao Chung <redacted>
---

 doc/mgmt-api.txt | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/doc/mgmt-api.txt b/doc/mgmt-api.txt
index 5355fedb0..06df3e914 100644
--- a/doc/mgmt-api.txt
+++ b/doc/mgmt-api.txt

@@ -107,7 +107,8 @@ Configuration command, Default Runtime Configuration Changed event, Get
 Device Flags command, Set Device Flags command, Device Flags Changed event,
 Read Advertisement Monitor Features command, Add Advertisement Patterns
 Monitor command, Remove Advertisement Monitor command, Advertisement Monitor
-Added event and Advertisement Monitor Removed event.
+Added event, Advertisement Monitor Removed event and Advertisement Monitor
+Device Tracking event.
 
 
 Example

@@ -4910,3 +4911,27 @@ Controller Resume Event
 	Address_Type. Otherwise, Address and Address_Type will both be zero.
 
 	This event will be sent to all management sockets.
+
+
+Advertisement Monitor Device Tracking Event
+===========================================
+
+	Event code:		0x002f
+	Controller Index:	<controller_id>
+	Event Parameters:	Monitor_Handle (2 octets)
+				Monitor_State (1 octet)
+				Address (6 octets)
+				Address_Type (1 octet)
+
+	This event indicates that the controller has started/stopped tracking
+	a particular device matching the Advertisement Monitor with handle
+	Monitor_Handle.
+
+	Possible values for the Monitor_State parameter:
+		0	The controller has stopped tracking a device
+		1	The controller has started tracking a device
+
+	The address of the device being tracked will be shared in Address and
+	Address_Type.
+
+	This event will be sent to all management sockets.

-- 
2.33.0.685.g46640cef36-goog

This patch adds a definition of the Advertisement Monitor Device
Tracking event.

---

 lib/mgmt.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/mgmt.h b/lib/mgmt.h
index 0a6349321..f23041f96 100644
--- a/lib/mgmt.h
+++ b/lib/mgmt.h

@@ -1014,6 +1014,13 @@ struct mgmt_ev_controller_resume {
 	uint8_t wake_reason;
 } __packed;
 
+#define MGMT_EV_ADV_MONITOR_TRACKING	0x002f
+struct mgmt_ev_adv_monitor_tracking {
+	uint16_t monitor_handle;
+	uint8_t monitor_state;
+	struct mgmt_addr_info addr;
+} __packed;
+
 static const char *mgmt_op[] = {
 	"<0x0000>",
 	"Read Version",

@@ -1152,6 +1159,7 @@ static const char *mgmt_ev[] = {
 	"Advertisement Monitor Removed",
 	"Controller Suspend",
 	"Controller Resume",
+	"Advertisement Monitor Device Tracking",	/* 0x002f */
 };
 
 static const char *mgmt_status[] = {

-- 
2.33.0.685.g46640cef36-goog

This patch registers a callback function to receive Advertisement
Monitor Device Tracking event.

Test performed:
- verified by logs that Monitor Device is received from the controller
  and sent to the bluetoothd when the controller starts/stops monitoring
  a bluetooth device.

---

 src/adv_monitor.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/adv_monitor.c b/src/adv_monitor.c
index 715ac5904..05bd49134 100644
--- a/src/adv_monitor.c
+++ b/src/adv_monitor.c

@@ -1531,6 +1531,27 @@ static void adv_monitor_removed_callback(uint16_t index, uint16_t length,
 		ev->monitor_handle);
 }
 
+/* Processes Adv Monitor tracking event from kernel */
+static void adv_monitor_tracking_callback(uint16_t index, uint16_t length,
+					  const void *param, void *user_data)
+{
+	struct btd_adv_monitor_manager *manager = user_data;
+	const struct mgmt_ev_adv_monitor_tracking *ev = param;
+	uint16_t handle = le16_to_cpu(ev->monitor_handle);
+	const uint16_t adapter_id = manager->adapter_id;
+	char addr[18];
+
+	if (length < sizeof(*ev)) {
+		btd_error(adapter_id,
+				"Wrong size of Adv Monitor Tracking event");
+		return;
+	}
+
+	ba2str(&ev->addr.bdaddr, addr);
+	DBG("Adv monitor with handle 0x%04x %s tracking device %s", handle,
+			ev->monitor_state ? "started" : "stopped", addr);
+}
+
 /* Allocates a manager object */
 static struct btd_adv_monitor_manager *manager_new(
 						struct btd_adapter *adapter,

@@ -1555,6 +1576,10 @@ static struct btd_adv_monitor_manager *manager_new(
 			manager->adapter_id, adv_monitor_removed_callback,
 			manager, NULL);
 
+	mgmt_register(manager->mgmt, MGMT_EV_ADV_MONITOR_TRACKING,
+			manager->adapter_id, adv_monitor_tracking_callback,
+			manager, NULL);
+
 	return manager;
 }
 

-- 
2.33.0.685.g46640cef36-goog

Hi Manish,

On Mon, Sep 27, 2021 at 1:17 PM Manish Mandlik [off-list ref] wrote:

I wonder if wouldn't it be better to indicate this over Device Found?
Or the controller will indicate the advertising report in addition to
this event? Btw, I think it is about time we introduce these commands
to the emulator in order to have proper CI tests, without it cannot
become a stable API.

--
2.33.0.685.g46640cef36-goog

-- 
Luiz Augusto von Dentz

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=553715

---Test result---

Test Summary:
CheckPatch                    PASS      4.10 seconds
GitLint                       PASS      2.72 seconds
Prep - Setup ELL              PASS      50.41 seconds
Build - Prep                  PASS      0.47 seconds
Build - Configure             PASS      9.43 seconds
Build - Make                  PASS      219.41 seconds
Make Check                    PASS      9.73 seconds
Make Distcheck                PASS      263.95 seconds
Build w/ext ELL - Configure   PASS      9.43 seconds
Build w/ext ELL - Make        PASS      203.37 seconds



---
Regards,
Linux Bluetooth

Hi Manish,

I have to echo Luiz's comment here. How is this suppose to work. We now get a Device Found and Device Tracked event?

Wouldn’t it be really better to have a “I am tracked” flag in the Device Found event?

Regards

Marcel