Re: [PATCH v2] Bluetooth: Add vendor-specific packet classification for ISO data

[Ying Hsu]

Hi Luiz,

I'm happy to move btusb_intel_classify_pkt_type into btintel.c in the
next patcheset.
As I only tested it on Intel USB BT controllers, I suggest Intel
further assess its applicability to other transports and future BT
controllers in another change.


On Thu, May 23, 2024 at 10:23 PM Luiz Augusto von Dentz
<luiz.dentz@xxxxxxxxx> wrote:
>
> Hi Ying,
>
> On Thu, May 23, 2024 at 2:09 AM Ying Hsu <yinghsu@xxxxxxxxxxxx> wrote:
> >
> > When HCI raw sockets are opened, the Bluetooth kernel module doesn't
> > track CIS/BIS connections. User-space applications have to identify
> > ISO data by maintaining connection information and look up the mapping
> > for each ACL data packet received. Besides, btsnoop log captured in
> > kernel couldn't tell ISO data from ACL data in this case.
> >
> > To avoid additional lookups, this patch introduces vendor-specific
> > packet classification for Intel BT controllers to distinguish
> > ISO data packets from ACL data packets.
> >
> > Signed-off-by: Ying Hsu <yinghsu@xxxxxxxxxxxx>
> > ---
> > Tested LE audio unicast recording on a ChromeOS device with Intel AX211
> >
> > Changes in v2:
> > - Adds vendor-specific packet classificaton in hci_dev.
> > - Keeps reclassification in hci_recv_frame.
> >
> >  drivers/bluetooth/btusb.c        | 19 +++++++++++++++++++
> >  include/net/bluetooth/hci_core.h |  1 +
> >  net/bluetooth/hci_core.c         | 16 ++++++++++++++++
> >  3 files changed, 36 insertions(+)
> >
> > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> > index 79aefdb3324d..75561e749c50 100644
> > --- a/drivers/bluetooth/btusb.c
> > +++ b/drivers/bluetooth/btusb.c
> > @@ -966,6 +966,24 @@ static void btusb_intel_cmd_timeout(struct hci_dev *hdev)
> >         gpiod_set_value_cansleep(reset_gpio, 0);
> >  }
> >
> > +#define BT_USB_INTEL_ISODATA_HANDLE_BASE 0x900
> > +
> > +static u8 btusb_intel_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
>
> We might as well move this to btintel.c since it should not be USB specific.
>
> > +{
> > +       /*
> > +        * Distinguish ISO data packets form ACL data packets
> > +        * based on their conneciton handle value range.
> > +        */
> > +       if (hci_skb_pkt_type(skb) == HCI_ACLDATA_PKT) {
> > +               __u16 handle = __le16_to_cpu(hci_acl_hdr(skb)->handle);
> > +
> > +               if (hci_handle(handle) >= BT_USB_INTEL_ISODATA_HANDLE_BASE)
> > +                       return HCI_ISODATA_PKT;
> > +       }
> > +
> > +       return hci_skb_pkt_type(skb);
> > +}
> > +
> >  #define RTK_DEVCOREDUMP_CODE_MEMDUMP           0x01
> >  #define RTK_DEVCOREDUMP_CODE_HW_ERR            0x02
> >  #define RTK_DEVCOREDUMP_CODE_CMD_TIMEOUT       0x03
> > @@ -4451,6 +4469,7 @@ static int btusb_probe(struct usb_interface *intf,
> >                 /* Transport specific configuration */
> >                 hdev->send = btusb_send_frame_intel;
> >                 hdev->cmd_timeout = btusb_intel_cmd_timeout;
> > +               hdev->classify_pkt_type = btusb_intel_classify_pkt_type;
> >
> >                 if (id->driver_info & BTUSB_INTEL_NO_WBS_SUPPORT)
> >                         btintel_set_flag(hdev, INTEL_ROM_LEGACY_NO_WBS_SUPPORT);
> > diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> > index 9231396fe96f..7b7068a84ff7 100644
> > --- a/include/net/bluetooth/hci_core.h
> > +++ b/include/net/bluetooth/hci_core.h
> > @@ -649,6 +649,7 @@ struct hci_dev {
> >         int (*get_codec_config_data)(struct hci_dev *hdev, __u8 type,
> >                                      struct bt_codec *codec, __u8 *vnd_len,
> >                                      __u8 **vnd_data);
> > +       u8 (*classify_pkt_type)(struct hci_dev *hdev, struct sk_buff *skb);
> >  };
> >
> >  #define HCI_PHY_HANDLE(handle) (handle & 0xff)
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index b3ee9ff17624..8b817a99cefd 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -2941,15 +2941,31 @@ int hci_reset_dev(struct hci_dev *hdev)
> >  }
> >  EXPORT_SYMBOL(hci_reset_dev);
> >
> > +static u8 hci_dev_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
> > +{
> > +       if (hdev->classify_pkt_type)
> > +               return hdev->classify_pkt_type(hdev, skb);
> > +
> > +       return hci_skb_pkt_type(skb);
> > +}
> > +
> >  /* Receive frame from HCI drivers */
> >  int hci_recv_frame(struct hci_dev *hdev, struct sk_buff *skb)
> >  {
> > +       u8 dev_pkt_type;
> > +
> >         if (!hdev || (!test_bit(HCI_UP, &hdev->flags)
> >                       && !test_bit(HCI_INIT, &hdev->flags))) {
> >                 kfree_skb(skb);
> >                 return -ENXIO;
> >         }
> >
> > +       /* Check if the driver agree with packet type classification */
> > +       dev_pkt_type = hci_dev_classify_pkt_type(hdev, skb);
> > +       if (hci_skb_pkt_type(skb) != dev_pkt_type) {
> > +               hci_skb_pkt_type(skb) = dev_pkt_type;
> > +       }
> > +
> >         switch (hci_skb_pkt_type(skb)) {
> >         case HCI_EVENT_PKT:
> >                 break;
> > --
> > 2.45.1.288.g0e0cd299f1-goog
> >
>
>
> --
> Luiz Augusto von Dentz