Date:   Wed, 25 May 2022 18:45:42 +0800
From:   Joseph Hwang <josephsih@...omium.org>
To:     linux-bluetooth@...r.kernel.org, marcel@...tmann.org,
        luiz.dentz@...il.com, pali@...nel.org
Cc:     josephsih@...gle.com, chromeos-bluetooth-upstreaming@...omium.org,
        Joseph Hwang <josephsih@...omium.org>,
        Archie Pusaka <apusaka@...omium.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH v5 2/5] Bluetooth: aosp: surface AOSP quality report through mgmt

When receiving a HCI vendor event, the kernel checks if it is an
AOSP bluetooth quality report. If yes, the event is sent to bluez
user space through the mgmt socket.

Signed-off-by: Joseph Hwang <josephsih@...omium.org>
Reviewed-by: Archie Pusaka <apusaka@...omium.org>
---

Changes in v5:
- Define "struct ext_vendor_prefix" to replace "struct vendor_prefix"
  so that extended vendor prefix = prefix + 1-octet subcode
- Define aosp_ext_prefix to provide AOSP extended prefix which is
  returned by aosp_get_ext_prefix().
- Redefine struct ext_vendor_event_prefix such that
  . it uses get_ext_vendor_prefix to get prefix and subcodes where
    the prefix and the prefix length may be variable and are not
    unknown until run time;
  . it uses vendor_func to handle a vendor event
  This table handles vendor events in a generic way.
- Rewrite hci_vendor_evt() so that it compares both vendor prefix
  and subcode to match a vendor event.
- Define set_ext_prefix() to create MSFT extended vendor prefix
  which is returned by msft_get_ext_prefix().
- Do not EXPORT_SYMBOL(mgmt_quality_report).
- Keep msft_get_ext_prefix in msft instead of hci_dev since it is
  not used by any drivers.

Changes in v3:
- Rebase to resolve the code conflict.
- Move aosp_quality_report_evt() from hci_event.c to aosp.c.
- A new patch (3/3) is added to enable the quality report feature.

Changes in v2:
- Scrap the two structures defined in aosp.c and use constants for
  size check.
- Do a basic size check about the quality report event. Do not pull
  data from the event in which the kernel has no interest.
- Define vendor event prefixes with which vendor events of distinct
  vendor specifications can be clearly differentiated.
- Use mgmt helpers to add the header and data to a mgmt skb.

 include/net/bluetooth/hci_core.h | 12 +++++++
 include/net/bluetooth/mgmt.h     |  7 +++++
 net/bluetooth/aosp.c             | 50 +++++++++++++++++++++++++++++
 net/bluetooth/aosp.h             | 18 +++++++++++
 net/bluetooth/hci_event.c        | 54 +++++++++++++++++++++++++++++++-
 net/bluetooth/mgmt.c             | 19 +++++++++++
 net/bluetooth/msft.c             | 28 ++++++++++++++++-
 net/bluetooth/msft.h             | 12 +++++--
 8 files changed, 195 insertions(+), 5 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 64d3a63759a8..f89738c6b973 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -328,6 +328,13 @@ struct amp_assoc {
 
 #define HCI_MAX_PAGES	3
 
+struct ext_vendor_prefix {
+	__u8 *prefix;
+	__u8 prefix_len;
+	__u8 *subcodes;
+	__u8 subcodes_len;
+};
+
 struct hci_dev {
 	struct list_head list;
 	struct mutex	lock;
@@ -1876,6 +1883,8 @@ 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);
+int mgmt_quality_report(struct hci_dev *hdev, void *data, u32 data_len,
+			u8 quality_spec);
 
 u8 hci_le_conn_update(struct hci_conn *conn, u16 min, u16 max, u16 latency,
 		      u16 to_multiplier);
@@ -1894,4 +1903,7 @@ void hci_copy_identity_address(struct hci_dev *hdev, bdaddr_t *bdaddr,
 
 #define TRANSPORT_TYPE_MAX	0x04
 
+#define QUALITY_SPEC_AOSP_BQR		0x0
+#define QUALITY_SPEC_INTEL_TELEMETRY	0x1
+
 #endif /* __HCI_CORE_H */
diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
index c1c2fd72d9e3..6ccd0067c295 100644
--- a/include/net/bluetooth/mgmt.h
+++ b/include/net/bluetooth/mgmt.h
@@ -1127,3 +1127,10 @@ struct mgmt_ev_adv_monitor_device_lost {
 	__le16 monitor_handle;
 	struct mgmt_addr_info addr;
 } __packed;
+
+#define MGMT_EV_QUALITY_REPORT			0x0031
+struct mgmt_ev_quality_report {
+	__u8	quality_spec;
+	__u32	data_len;
+	__u8	data[];
+} __packed;
diff --git a/net/bluetooth/aosp.c b/net/bluetooth/aosp.c
index 432ae3aac9e3..94faa15b1ea0 100644
--- a/net/bluetooth/aosp.c
+++ b/net/bluetooth/aosp.c
@@ -199,3 +199,53 @@ int aosp_set_quality_report(struct hci_dev *hdev, bool enable)
 	else
 		return disable_quality_report(hdev);
 }
+
+/* The following LEN = 1-byte Sub-event code + 48-byte Sub-event Parameters */
+#define BLUETOOTH_QUALITY_REPORT_LEN 49
+
+bool aosp_check_quality_report_len(struct sk_buff *skb)
+{
+	/* skb->len is allowed to be larger than BLUETOOTH_QUALITY_REPORT_LEN
+	 * to accommodate an additional Vendor Specific Parameter (vsp) field.
+	 */
+	if (skb->len < BLUETOOTH_QUALITY_REPORT_LEN) {
+		BT_ERR("AOSP evt data len %d too short (%u expected)",
+		       skb->len, BLUETOOTH_QUALITY_REPORT_LEN);
+		return false;
+	}
+
+	return true;
+}
+
+/* AOSP HCI Requirements use 0x54 and up as sub-event codes without
+ * actually defining a vendor prefix. Refer to
+ * https://source.android.com/devices/bluetooth/hci_requirements
+ * Hence, the other vendor event prefixes should not use the same
+ * space to avoid collision.
+ * Since the AOSP does not define a prefix, its prefix is NULL
+ * and prefix_len is 0.
+ * While there are a number of subcodes in AOSP, only interested in
+ * Bluetooth Quality Report (0x58) for now.
+ */
+#define AOSP_EV_QUALITY_REPORT		0x58
+
+static unsigned char AOSP_SUBCODES[] = { AOSP_EV_QUALITY_REPORT };
+
+static struct ext_vendor_prefix aosp_ext_prefix = {
+	.prefix		= NULL,
+	.prefix_len	= 0,
+	.subcodes	= AOSP_SUBCODES,
+	.subcodes_len	= sizeof(AOSP_SUBCODES),
+};
+
+struct ext_vendor_prefix *aosp_get_ext_prefix(struct hci_dev *hdev)
+{
+	return &aosp_ext_prefix;
+}
+
+void aosp_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	if (aosp_has_quality_report(hdev) && aosp_check_quality_report_len(skb))
+		mgmt_quality_report(hdev, skb->data, skb->len,
+				    QUALITY_SPEC_AOSP_BQR);
+}
diff --git a/net/bluetooth/aosp.h b/net/bluetooth/aosp.h
index 2fd8886d51b2..8208e01fffed 100644
--- a/net/bluetooth/aosp.h
+++ b/net/bluetooth/aosp.h
@@ -10,6 +10,9 @@ void aosp_do_close(struct hci_dev *hdev);
 
 bool aosp_has_quality_report(struct hci_dev *hdev);
 int aosp_set_quality_report(struct hci_dev *hdev, bool enable);
+bool aosp_check_quality_report_len(struct sk_buff *skb);
+struct ext_vendor_prefix *aosp_get_ext_prefix(struct hci_dev *hdev);
+void aosp_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb);
 
 #else
 
@@ -26,4 +29,19 @@ static inline int aosp_set_quality_report(struct hci_dev *hdev, bool enable)
 	return -EOPNOTSUPP;
 }
 
+static inline bool aosp_check_quality_report_len(struct sk_buff *skb)
+{
+	return false;
+}
+
+static inline struct ext_vendor_prefix *
+aosp_get_ext_prefix(struct hci_dev *hdev)
+{
+	return NULL;
+}
+
+static inline void aosp_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+}
+
 #endif
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 0270e597c285..c2c6725678ec 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -37,6 +37,7 @@
 #include "smp.h"
 #include "msft.h"
 #include "eir.h"
+#include "aosp.h"
 
 #define ZERO_KEY "\x00\x00\x00\x00\x00\x00\x00\x00" \
 		 "\x00\x00\x00\x00\x00\x00\x00\x00"
@@ -4259,6 +4260,57 @@ static void hci_num_comp_blocks_evt(struct hci_dev *hdev, void *data,
 	queue_work(hdev->workqueue, &hdev->tx_work);
 }
 
+/* Every distinct vendor specification must have a well-defined vendor
+ * event prefix to determine if a vendor event meets the specification.
+ * Some vendor prefixes are fixed values while some other vendor prefixes
+ * are only available at run time.
+ */
+struct ext_vendor_event_prefix {
+	/* Some vendor prefixes are variable length. For convenience,
+	 * the prefix in struct ext_vendor_prefix is in little endian.
+	 */
+	struct ext_vendor_prefix *
+		(*get_ext_vendor_prefix)(struct hci_dev *hdev);
+	void (*vendor_func)(struct hci_dev *hdev, struct sk_buff *skb);
+} evt_prefixes[] = {
+	{ aosp_get_ext_prefix, aosp_vendor_evt },
+	{ msft_get_ext_prefix, msft_vendor_evt },
+
+	/* end with a null entry */
+	{},
+};
+
+static void hci_vendor_evt(struct hci_dev *hdev, void *data,
+			   struct sk_buff *skb)
+{
+	int i, j;
+	struct ext_vendor_prefix *vnd;
+	__u8 subcode;
+
+	for (i = 0; evt_prefixes[i].get_ext_vendor_prefix; i++) {
+		vnd = evt_prefixes[i].get_ext_vendor_prefix(hdev);
+		if (!vnd)
+			continue;
+
+		/* Compare the raw prefix data in little endian directly. */
+		if (memcmp(vnd->prefix, skb->data, vnd->prefix_len))
+			continue;
+
+		/* Make sure that there are more data after prefix. */
+		if (skb->len <= vnd->prefix_len)
+			continue;
+
+		/* The subcode is the single octet following the prefix. */
+		subcode = skb->data[vnd->prefix_len];
+		for (j = 0; j < vnd->subcodes_len; j++) {
+			if (vnd->subcodes[j] == subcode) {
+				evt_prefixes[i].vendor_func(hdev, skb);
+				break;
+			}
+		}
+	}
+}
+
 static void hci_mode_change_evt(struct hci_dev *hdev, void *data,
 				struct sk_buff *skb)
 {
@@ -6879,7 +6931,7 @@ static const struct hci_ev {
 	HCI_EV(HCI_EV_NUM_COMP_BLOCKS, hci_num_comp_blocks_evt,
 	       sizeof(struct hci_ev_num_comp_blocks)),
 	/* [0xff = HCI_EV_VENDOR] */
-	HCI_EV_VL(HCI_EV_VENDOR, msft_vendor_evt, 0, HCI_MAX_EVENT_SIZE),
+	HCI_EV_VL(HCI_EV_VENDOR, hci_vendor_evt, 0, HCI_MAX_EVENT_SIZE),
 };
 
 static void hci_event_func(struct hci_dev *hdev, u8 event, struct sk_buff *skb,
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 1ad84f34097f..9d3666bdd07c 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -4332,6 +4332,25 @@ static int set_exp_feature(struct sock *sk, struct hci_dev *hdev,
 			       MGMT_STATUS_NOT_SUPPORTED);
 }
 
+int mgmt_quality_report(struct hci_dev *hdev, void *data, u32 data_len,
+			u8 quality_spec)
+{
+	struct mgmt_ev_quality_report *ev;
+	struct sk_buff *skb;
+
+	skb = mgmt_alloc_skb(hdev, MGMT_EV_QUALITY_REPORT,
+			     sizeof(*ev) + data_len);
+	if (!skb)
+		return -ENOMEM;
+
+	ev = skb_put(skb, sizeof(*ev));
+	ev->quality_spec = quality_spec;
+	ev->data_len = data_len;
+	skb_put_data(skb, data, data_len);
+
+	return mgmt_event_skb(skb, NULL);
+}
+
 static int get_device_flags(struct sock *sk, struct hci_dev *hdev, void *data,
 			    u16 data_len)
 {
diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
index f43994523b1f..c003e94faccd 100644
--- a/net/bluetooth/msft.c
+++ b/net/bluetooth/msft.c
@@ -116,6 +116,20 @@ bool msft_monitor_supported(struct hci_dev *hdev)
 	return !!(msft_get_features(hdev) & MSFT_FEATURE_MASK_LE_ADV_MONITOR);
 }
 
+/* Add the MSFT vendor event subcodes into MSFT_SUBCODES which
+ * msft_vendor_evt() is interested in handling.
+ */
+static unsigned char MSFT_SUBCODES[] = { MSFT_EV_LE_MONITOR_DEVICE };
+static struct ext_vendor_prefix msft_ext_prefix = { 0 };
+
+static void set_ext_prefix(struct msft_data *msft)
+{
+	msft_ext_prefix.prefix = msft->evt_prefix;
+	msft_ext_prefix.prefix_len = msft->evt_prefix_len;
+	msft_ext_prefix.subcodes = MSFT_SUBCODES;
+	msft_ext_prefix.subcodes_len = sizeof(MSFT_SUBCODES);
+}
+
 static bool read_supported_features(struct hci_dev *hdev,
 				    struct msft_data *msft)
 {
@@ -156,6 +170,8 @@ static bool read_supported_features(struct hci_dev *hdev,
 	if (msft->features & MSFT_FEATURE_MASK_CURVE_VALIDITY)
 		hdev->msft_curve_validity = true;
 
+	set_ext_prefix(msft);
+
 	kfree_skb(skb);
 	return true;
 
@@ -742,7 +758,17 @@ static void msft_monitor_device_evt(struct hci_dev *hdev, struct sk_buff *skb)
 				 handle_data->mgmt_handle);
 }
 
-void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb)
+struct ext_vendor_prefix *msft_get_ext_prefix(struct hci_dev *hdev)
+{
+	struct msft_data *msft = hdev->msft_data;
+
+	if (!msft)
+		return NULL;
+
+	return &msft_ext_prefix;
+}
+
+void msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct msft_data *msft = hdev->msft_data;
 	u8 *evt_prefix;
diff --git a/net/bluetooth/msft.h b/net/bluetooth/msft.h
index afcaf7d3b1cb..1515ae06c628 100644
--- a/net/bluetooth/msft.h
+++ b/net/bluetooth/msft.h
@@ -17,7 +17,7 @@ void msft_register(struct hci_dev *hdev);
 void msft_unregister(struct hci_dev *hdev);
 void msft_do_open(struct hci_dev *hdev);
 void msft_do_close(struct hci_dev *hdev);
-void msft_vendor_evt(struct hci_dev *hdev, void *data, struct sk_buff *skb);
+void msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb);
 __u64 msft_get_features(struct hci_dev *hdev);
 int msft_add_monitor_pattern(struct hci_dev *hdev, struct adv_monitor *monitor);
 int msft_remove_monitor(struct hci_dev *hdev, struct adv_monitor *monitor,
@@ -27,6 +27,7 @@ int msft_set_filter_enable(struct hci_dev *hdev, bool enable);
 int msft_suspend_sync(struct hci_dev *hdev);
 int msft_resume_sync(struct hci_dev *hdev);
 bool msft_curve_validity(struct hci_dev *hdev);
+struct ext_vendor_prefix *msft_get_ext_prefix(struct hci_dev *hdev);
 
 #else
 
@@ -39,8 +40,7 @@ static inline void msft_register(struct hci_dev *hdev) {}
 static inline void msft_unregister(struct hci_dev *hdev) {}
 static inline void msft_do_open(struct hci_dev *hdev) {}
 static inline void msft_do_close(struct hci_dev *hdev) {}
-static inline void msft_vendor_evt(struct hci_dev *hdev, void *data,
-				   struct sk_buff *skb) {}
+static inline void msft_vendor_evt(struct hci_dev *hdev, struct sk_buff *skb) {}
 static inline __u64 msft_get_features(struct hci_dev *hdev) { return 0; }
 static inline int msft_add_monitor_pattern(struct hci_dev *hdev,
 					   struct adv_monitor *monitor)
@@ -77,4 +77,10 @@ static inline bool msft_curve_validity(struct hci_dev *hdev)
 	return false;
 }
 
+static inline struct ext_vendor_prefix *
+msft_get_ext_prefix(struct hci_dev *hdev)
+{
+	return NULL;
+}
+
 #endif
-- 
2.36.1.124.g0e6072fb45-goog

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