Re: [PATCH v7 2/2] bluetooth: Add MGMT Adv Monitor Device Found/Lost events

From: Luiz Augusto von Dentz
Date: Mon Dec 13 2021 - 12:21:15 EST

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Hi Manish,

On Mon, Dec 6, 2021 at 8:39 AM Manish Mandlik <mmandlik@xxxxxxxxxx> wrote:
>
> Hi Luiz,
>
> On Fri, Dec 3, 2021 at 5:19 PM Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote:
>>
>> Hi Manish,
>>
>> On Thu, Dec 2, 2021 at 11:16 PM Manish Mandlik <mmandlik@xxxxxxxxxx> wrote:
>> >
>> > This patch introduces two new MGMT events for notifying the bluetoothd
>> > whenever the controller starts/stops monitoring a device.
>> >
>> > Test performed:
>> > - Verified by logs that the MSFT Monitor Device is received from the
>> > controller and the bluetoothd is notified whenever the controller
>> > starts/stops monitoring a device.
>> >
>> > Signed-off-by: Manish Mandlik <mmandlik@xxxxxxxxxx>
>> > Reviewed-by: Miao-chen Chou <mcchou@xxxxxxxxxx>
>> >
>> > ---
>> >
>> > Changes in v7:
>> > - Refactor mgmt_device_found() to fix stack frame size limit
>> >
>> > Changes in v6:
>> > - Fix compiler warning for mgmt_adv_monitor_device_found().
>> >
>> > Changes in v5:
>> > - New patch in the series. Split previous patch into two.
>> > - Update the Device Found logic to send existing Device Found event or
>> > Adv Monitor Device Found event depending on the active scanning state.
>> >
>> > include/net/bluetooth/hci_core.h | 3 +
>> > include/net/bluetooth/mgmt.h | 16 +++++
>> > net/bluetooth/mgmt.c | 106 +++++++++++++++++++++++++++++--
>> > net/bluetooth/msft.c | 15 ++++-
>> > 4 files changed, 134 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
>> > index 5ccd19dec77c..3b53214ff49f 100644
>> > --- a/include/net/bluetooth/hci_core.h
>> > +++ b/include/net/bluetooth/hci_core.h
>> > @@ -599,6 +599,7 @@ struct hci_dev {
>> > struct delayed_work interleave_scan;
>> >
>> > struct list_head monitored_devices;
>> > + bool advmon_pend_notify;
>> >
>> > #if IS_ENABLED(CONFIG_BT_LEDS)
>> > struct led_trigger *power_led;
>> > @@ -1847,6 +1848,8 @@ void mgmt_adv_monitor_removed(struct hci_dev *hdev, u16 handle);
>> > int mgmt_phy_configuration_changed(struct hci_dev *hdev, struct sock *skip);
>> > int mgmt_add_adv_patterns_monitor_complete(struct hci_dev *hdev, u8 status);
>> > int mgmt_remove_adv_monitor_complete(struct hci_dev *hdev, u8 status);
>> > +void mgmt_adv_monitor_device_lost(struct hci_dev *hdev, u16 handle,
>> > + bdaddr_t *bdaddr, u8 addr_type);
>> >
>> > u8 hci_le_conn_update(struct hci_conn *conn, u16 min, u16 max, u16 latency,
>> > u16 to_multiplier);
>> > diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
>> > index 107b25deae68..99266f7aebdc 100644
>> > --- a/include/net/bluetooth/mgmt.h
>> > +++ b/include/net/bluetooth/mgmt.h
>> > @@ -1104,3 +1104,19 @@ struct mgmt_ev_controller_resume {
>> > #define MGMT_WAKE_REASON_NON_BT_WAKE 0x0
>> > #define MGMT_WAKE_REASON_UNEXPECTED 0x1
>> > #define MGMT_WAKE_REASON_REMOTE_WAKE 0x2
>> > +
>> > +#define MGMT_EV_ADV_MONITOR_DEVICE_FOUND 0x002f
>> > +struct mgmt_ev_adv_monitor_device_found {
>> > + __le16 monitor_handle;
>> > + struct mgmt_addr_info addr;
>> > + __s8 rssi;
>> > + __le32 flags;
>> > + __le16 eir_len;
>> > + __u8 eir[0];
>> > +} __packed;
>> > +
>> > +#define MGMT_EV_ADV_MONITOR_DEVICE_LOST 0x0030
>> > +struct mgmt_ev_adv_monitor_device_lost {
>> > + __le16 monitor_handle;
>> > + struct mgmt_addr_info addr;
>> > +} __packed;
>> > diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
>> > index bf989ae03f9f..06e0769f350d 100644
>> > --- a/net/bluetooth/mgmt.c
>> > +++ b/net/bluetooth/mgmt.c
>> > @@ -174,6 +174,8 @@ static const u16 mgmt_events[] = {
>> > MGMT_EV_ADV_MONITOR_REMOVED,
>> > MGMT_EV_CONTROLLER_SUSPEND,
>> > MGMT_EV_CONTROLLER_RESUME,
>> > + MGMT_EV_ADV_MONITOR_DEVICE_FOUND,
>> > + MGMT_EV_ADV_MONITOR_DEVICE_LOST,
>> > };
>> >
>> > static const u16 mgmt_untrusted_commands[] = {
>> > @@ -9524,6 +9526,100 @@ static bool is_filter_match(struct hci_dev *hdev, s8 rssi, u8 *eir,
>> > return true;
>> > }
>> >
>> > +void mgmt_adv_monitor_device_lost(struct hci_dev *hdev, u16 handle,
>> > + bdaddr_t *bdaddr, u8 addr_type)
>> > +{
>> > + struct mgmt_ev_adv_monitor_device_lost ev;
>> > +
>> > + ev.monitor_handle = cpu_to_le16(handle);
>> > + bacpy(&ev.addr.bdaddr, bdaddr);
>> > + ev.addr.type = addr_type;
>> > +
>> > + mgmt_event(MGMT_EV_ADV_MONITOR_DEVICE_LOST, hdev, &ev, sizeof(ev),
>> > + NULL);
>> > +}
>> > +
>> > +static void mgmt_adv_monitor_device_found(struct hci_dev *hdev,
>> > + struct mgmt_ev_device_found *ev,
>> > + size_t ev_size, bool discovering)
>> > +{
>> > + char buf[518];
>>
>> We should try to avoid declaring such big stack variable, instead Im
>> working on a set the should enable you to use skb_put/skb_put_data
>> directly into the skb, here are the current changes I have for
>> device_found:
>>
>> https://gist.github.com/Vudentz/ffce584912eb7dc4add9c3bb25466fa5
>>
>> I'm addressing Marcel's comments and will send the set to the list later today.
>
> Please let me know once these changes land bluetooth-next, I'll update my patch and send out the new revision.

Those changes are already in bluetooth-next.

>>
>>
>> > + struct mgmt_ev_adv_monitor_device_found *advmon_ev = (void *)buf;
>> > + size_t advmon_ev_size;
>> > + struct monitored_device *dev, *tmp;
>> > + bool matched = false;
>> > + bool notified = false;
>> > +
>> > + /* We have received the Advertisement Report because:
>> > + * 1. the kernel has initiated active discovery
>> > + * 2. if not, we have pend_le_reports > 0 in which case we are doing
>> > + * passive scanning
>> > + * 3. if none of the above is true, we have one or more active
>> > + * Advertisement Monitor
>> > + *
>> > + * For case 1 and 2, report all advertisements via MGMT_EV_DEVICE_FOUND
>> > + * and report ONLY one advertisement per device for the matched Monitor
>> > + * via MGMT_EV_ADV_MONITOR_DEVICE_FOUND event.
>> > + *
>> > + * For case 3, since we are not active scanning and all advertisements
>> > + * received are due to a matched Advertisement Monitor, report all
>> > + * advertisements ONLY via MGMT_EV_ADV_MONITOR_DEVICE_FOUND event.
>> > + */
>> > + if (discovering) {
>> > + mgmt_event(MGMT_EV_DEVICE_FOUND, hdev, ev, ev_size, NULL);
>> > +
>> > + if (!hdev->advmon_pend_notify)
>> > + return;
>> > + }
>> > +
>> > + /* Make sure that the buffer is big enough */
>> > + advmon_ev_size = ev_size + (sizeof(*advmon_ev) - sizeof(*ev));
>> > + if (advmon_ev_size > sizeof(buf))
>> > + return;
>> > +
>> > + /* ADV_MONITOR_DEVICE_FOUND is similar to DEVICE_FOUND event except
>> > + * that it also has 'monitor_handle'. Make a copy of DEVICE_FOUND and
>> > + * store monitor_handle of the matched monitor.
>> > + */
>> > + memcpy(&advmon_ev->addr, ev, ev_size);
>> > +
>> > + hdev->advmon_pend_notify = false;
>> > +
>> > + list_for_each_entry_safe(dev, tmp, &hdev->monitored_devices, list) {
>> > + if (!bacmp(&dev->bdaddr, &advmon_ev->addr.bdaddr)) {
>> > + matched = true;
>> > +
>> > + if (!dev->notified) {
>> > + advmon_ev->monitor_handle =
>> > + cpu_to_le16(dev->handle);
>> > +
>> > + mgmt_event(MGMT_EV_ADV_MONITOR_DEVICE_FOUND,
>> > + hdev, advmon_ev, advmon_ev_size,
>> > + NULL);
>> > +
>> > + notified = true;
>> > + dev->notified = true;
>> > + }
>> > + }
>> > +
>> > + if (!dev->notified)
>> > + hdev->advmon_pend_notify = true;
>> > + }
>> > +
>> > + if (!discovering &&
>> > + ((matched && !notified) || !msft_monitor_supported(hdev))) {
>> > + /* Handle 0 indicates that we are not active scanning and this
>> > + * is a subsequent advertisement report for an already matched
>> > + * Advertisement Monitor or the controller offloading support
>> > + * is not available.
>> > + */
>> > + advmon_ev->monitor_handle = 0;
>> > +
>> > + mgmt_event(MGMT_EV_ADV_MONITOR_DEVICE_FOUND, hdev, advmon_ev,
>> > + advmon_ev_size, NULL);
>> > + }
>> > +}
>> > +
>> > void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>> > u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
>> > u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
>> > @@ -9531,6 +9627,7 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>> > char buf[512];
>> > struct mgmt_ev_device_found *ev = (void *)buf;
>> > size_t ev_size;
>> > + bool report_device_found = hci_discovery_active(hdev);
>> >
>> > /* Don't send events for a non-kernel initiated discovery. With
>> > * LE one exception is if we have pend_le_reports > 0 in which
>> > @@ -9539,11 +9636,10 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>> > if (!hci_discovery_active(hdev)) {
>> > if (link_type == ACL_LINK)
>> > return;
>> > - if (link_type == LE_LINK &&
>> > - list_empty(&hdev->pend_le_reports) &&
>> > - !hci_is_adv_monitoring(hdev)) {
>> > + if (link_type == LE_LINK && !list_empty(&hdev->pend_le_reports))
>> > + report_device_found = true;
>> > + else if (!hci_is_adv_monitoring(hdev))
>> > return;
>> > - }
>> > }
>> >
>> > if (hdev->discovery.result_filtering) {
>> > @@ -9606,7 +9702,7 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>> > ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
>> > ev_size = sizeof(*ev) + eir_len + scan_rsp_len;
>> >
>> > - mgmt_event(MGMT_EV_DEVICE_FOUND, hdev, ev, ev_size, NULL);
>> > + mgmt_adv_monitor_device_found(hdev, ev, ev_size, report_device_found);
>> > }
>> >
>> > void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>> > diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
>> > index aadabe78baf6..3e2385562d2b 100644
>> > --- a/net/bluetooth/msft.c
>> > +++ b/net/bluetooth/msft.c
>> > @@ -579,8 +579,16 @@ void msft_do_close(struct hci_dev *hdev)
>> >
>> > hci_dev_lock(hdev);
>> >
>> > - /* Clear any devices that are being monitored */
>> > + /* Clear any devices that are being monitored and notify device lost */
>> > +
>> > + hdev->advmon_pend_notify = false;
>> > +
>> > list_for_each_entry_safe(dev, tmp_dev, &hdev->monitored_devices, list) {
>> > + if (dev->notified)
>> > + mgmt_adv_monitor_device_lost(hdev, dev->handle,
>> > + &dev->bdaddr,
>> > + dev->addr_type);
>> > +
>> > list_del(&dev->list);
>> > kfree(dev);
>> > }
>> > @@ -639,6 +647,7 @@ static void msft_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr,
>> >
>> > INIT_LIST_HEAD(&dev->list);
>> > list_add(&dev->list, &hdev->monitored_devices);
>> > + hdev->advmon_pend_notify = true;
>> > }
>> >
>> > /* This function requires the caller holds hdev->lock */
>> > @@ -649,6 +658,10 @@ static void msft_device_lost(struct hci_dev *hdev, bdaddr_t *bdaddr,
>> >
>> > list_for_each_entry_safe(dev, tmp, &hdev->monitored_devices, list) {
>> > if (dev->handle == mgmt_handle) {
>> > + if (dev->notified)
>> > + mgmt_adv_monitor_device_lost(hdev, mgmt_handle,
>> > + bdaddr, addr_type);
>> > +
>> > list_del(&dev->list);
>> > kfree(dev);
>> >
>> > --
>> > 2.34.0.384.gca35af8252-goog
>> >
>>
>>
>> --
>> Luiz Augusto von Dentz
>
>
> Thanks,
> Manish.

--
Luiz Augusto von Dentz

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