[PATCH v3 4/7] Bluetooth: hci_event: Ignore reserved bits in LE Extended Adv Report

From: Sven Peter
Date: Mon Sep 19 2022 - 12:50:06 EST


Broadcom controllers present on Apple Silicon devices use the upper
8 bits of the event type in the LE Extended Advertising Report for
the channel on which the frame has been received.
These bits are reserved according to the Bluetooth spec anyway such that
we can just drop them to ensure that the advertising results are parsed
correctly.

The following excerpt from a btmon trace shows a report received on
channel 37 by these controllers:

> HCI Event: LE Meta Event (0x3e) plen 55
LE Extended Advertising Report (0x0d)
Num reports: 1
Entry 0
Event type: 0x2513
Props: 0x0013
Connectable
Scannable
Use legacy advertising PDUs
Data status: Complete
Reserved (0x2500)
Legacy PDU Type: Reserved (0x2513)
Address type: Public (0x00)
Address: XX:XX:XX:XX:XX:XX (Shenzhen Jingxun Software [...])
Primary PHY: LE 1M
Secondary PHY: No packets
SID: no ADI field (0xff)
TX power: 127 dBm
RSSI: -76 dBm (0xb4)
Periodic advertising interval: 0.00 msec (0x0000)
Direct address type: Public (0x00)
Direct address: 00:00:00:00:00:00 (OUI 00-00-00)
Data length: 0x1d
[...]
Flags: 0x18
Simultaneous LE and BR/EDR (Controller)
Simultaneous LE and BR/EDR (Host)
Company: Harman International Industries, Inc. (87)
Data: [...]
Service Data (UUID 0xfddf):
Name (complete): JBL Flip 5

Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
---
changes from v2:
- removed quirk and apply mask unconditionally since only bit 0-6
are used according to the spec
changes from v1:
- adjusted the commit message a bit to make checkpatch happy

include/net/bluetooth/hci.h | 1 +
net/bluetooth/hci_event.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index cf29511b25a8..556916110636 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -2576,6 +2576,7 @@ struct hci_ev_le_conn_complete {
#define LE_EXT_ADV_DIRECT_IND 0x0004
#define LE_EXT_ADV_SCAN_RSP 0x0008
#define LE_EXT_ADV_LEGACY_PDU 0x0010
+#define LE_EXT_ADV_EVT_TYPE_MASK 0x007f

#define ADDR_LE_DEV_PUBLIC 0x00
#define ADDR_LE_DEV_RANDOM 0x01
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 6643c9c20fa4..00616cae596a 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -6481,7 +6481,7 @@ static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, void *data,
info->length))
break;

- evt_type = __le16_to_cpu(info->type);
+ evt_type = __le16_to_cpu(info->type) & LE_EXT_ADV_EVT_TYPE_MASK;
legacy_evt_type = ext_evt_type_to_legacy(hdev, evt_type);
if (legacy_evt_type != LE_ADV_INVALID) {
process_adv_report(hdev, legacy_evt_type, &info->bdaddr,
--
2.25.1