[PATCH v4] Bluetooth: Add vendor-specific packet classification for ISO data

[Ying Hsu]

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 v4:
- Only register classify_pkt_type on AX211 (GfP2) and BE200 (GaP).

Changes in v3:
- Move Intel's classify_pkt_type implementation from btusb.c to btintel.c.

Changes in v2:
- Adds vendor-specific packet classificaton in hci_dev.
- Keeps reclassification in hci_recv_frame.

 drivers/bluetooth/btintel.c      | 25 +++++++++++++++++++++++--
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_core.c         | 16 ++++++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index 27e03951e68b..ff33e1aa2929 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c
@@ -2549,6 +2549,24 @@ static void btintel_set_dsm_reset_method(struct hci_dev *hdev,
 	data->acpi_reset_method = btintel_acpi_reset_method;
 }
 
+#define BTINTEL_ISODATA_HANDLE_BASE 0x900
+
+static u8 btintel_classify_pkt_type(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	/*
+	 * Distinguish ISO data packets form ACL data packets
+	 * based on their connection 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) >= BTINTEL_ISODATA_HANDLE_BASE)
+			return HCI_ISODATA_PKT;
+	}
+
+	return hci_skb_pkt_type(skb);
+}
+
 int btintel_bootloader_setup_tlv(struct hci_dev *hdev,
 				 struct intel_version_tlv *ver)
 {
@@ -2989,11 +3007,14 @@ static int btintel_setup_combined(struct hci_dev *hdev)
 		err = btintel_bootloader_setup(hdev, &ver);
 		btintel_register_devcoredump_support(hdev);
 		break;
+	case 0x18: /* GfP2 */
+	case 0x1c: /* GaP */
+		/* Re-classify packet type for controllers with LE audio */
+		hdev->classify_pkt_type = btintel_classify_pkt_type;
+		fallthrough;
 	case 0x17:
-	case 0x18:
 	case 0x19:
 	case 0x1b:
-	case 0x1c:
 	case 0x1e:
 		/* Display version information of TLV type */
 		btintel_version_info_tlv(hdev, &ver_tlv);
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