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Message-ID: <CABBYNZLXzc2QDJ-8_XaoOSL+CXnrfHi-t8DPRTjO+wJjmCbV-w@mail.gmail.com>
Date: Thu, 26 May 2022 13:25:44 -0700
From: Luiz Augusto von Dentz <luiz.dentz@...il.com>
To: Joseph Hwang <josephsih@...omium.org>
Cc: linux-bluetooth@...r.kernel.org, marcel@...tmann.org,
pali@...nel.org, chromeos-bluetooth-upstreaming@...omium.org,
josephsih@...gle.com, kernel test robot <lkp@...el.com>,
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: Re: [PATCH v6 2/5] Bluetooth: aosp: surface AOSP quality report
through mgmt
Hi Joseph,
On Thu, May 26, 2022 at 4:21 AM Joseph Hwang <josephsih@...omium.org> wrote:
>
> 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.
>
> Reported-by: kernel test robot <lkp@...el.com>
>
> Signed-off-by: Joseph Hwang <josephsih@...omium.org>
> Reviewed-by: Archie Pusaka <apusaka@...omium.org>
> ---
>
> Changes in v6:
> - Fixed a sparse check warning about using static for evt_prefixes.
>
> 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..8398971eddf4 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.
> + */
> +static 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;
> + }
> + }
> + }
> +}
I recall saying that having such matching logic applied without the
driver confirming that is the structure it using to be a bad idea
since it could actually cause an event to misinterpret and cause bad
behavior, instead we probably need a callback that gets populated by
the driver e.g.(hdev->vendor_evt) then the driver can either populate
with hci_vendor_evt if it does use prefixes or its own specialized
function or NULL if it doesn't use vendor events, specially for old
controllers Id leave it as NULL.
> 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
>
--
Luiz Augusto von Dentz
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