Hi Marcel,
On Wednesday 08 of April 2015 01:25:20 Marcel Holtmann wrote:
> When establishing a Bluetooth LE connection, read the remote used
> features mask to determine which features are supported. This was
> not really needed with Bluetooth 4.0, but since Bluetooth 4.1 and
> also 4.2 have introduced new optional features, this becomes more
> important.
>
> This works the same as with BR/EDR where the connection enters the
> BT_CONFIG stage and hci_connect_cfm call is delayed until the remote
> features have been retrieved. Only after successfully receiving the
> remote features, the connection enters the BT_CONNECTED state.
>
> Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> ---
> include/net/bluetooth/hci.h | 12 ++++++++
> net/bluetooth/hci_event.c | 75 +++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 85 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 2f8c830e600c..cb568ecc43a5 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -1376,6 +1376,11 @@ struct hci_cp_le_conn_update {
> __le16 max_ce_len;
> } __packed;
>
> +#define HCI_OP_LE_READ_REMOTE_FEATURES 0x2016
> +struct hci_cp_le_read_remote_features {
> + __le16 handle;
> +} __packed;
> +
> #define HCI_OP_LE_START_ENC 0x2019
> struct hci_cp_le_start_enc {
> __le16 handle;
> @@ -1868,6 +1873,13 @@ struct hci_ev_le_conn_update_complete {
> __le16 supervision_timeout;
> } __packed;
>
> +#define HCI_EV_LE_REMOTE_FEAT_COMPLETE 0x04
> +struct hci_ev_le_remote_feat_complete {
> + __u8 status;
> + __le16 handle;
> + __u8 features[8];
> +} __packed;
> +
> #define HCI_EV_LE_LTK_REQ 0x05
> struct hci_ev_le_ltk_req {
> __le16 handle;
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 01031038eb0e..123a6400a9d7 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -2036,6 +2036,33 @@ unlock:
> hci_dev_unlock(hdev);
> }
>
> +static void hci_cs_le_read_remote_features(struct hci_dev *hdev, u8 status)
> +{
> + struct hci_cp_le_read_remote_features *cp;
> + struct hci_conn *conn;
> +
> + BT_DBG("%s status 0x%2.2x", hdev->name, status);
> +
> + if (!status)
> + return;
> +
> + cp = hci_sent_cmd_data(hdev, HCI_OP_LE_READ_REMOTE_FEATURES);
> + if (!cp)
> + return;
> +
> + hci_dev_lock(hdev);
> +
> + conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(cp->handle));
> + if (conn) {
> + if (conn->state == BT_CONFIG) {
> + hci_connect_cfm(conn, status);
> + hci_conn_drop(conn);
> + }
> + }
> +
> + hci_dev_unlock(hdev);
> +}
> +
> static void hci_cs_le_start_enc(struct hci_dev *hdev, u8 status)
> {
> struct hci_cp_le_start_enc *cp;
> @@ -3104,6 +3131,10 @@ static void hci_cmd_status_evt(struct hci_dev *hdev, struct sk_buff *skb,
> hci_cs_le_create_conn(hdev, ev->status);
> break;
>
> + case HCI_OP_LE_READ_REMOTE_FEATURES:
> + hci_cs_le_read_remote_features(hdev, ev->status);
> + break;
> +
> case HCI_OP_LE_START_ENC:
> hci_cs_le_start_enc(hdev, ev->status);
> break;
> @@ -4515,7 +4546,7 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
>
> conn->sec_level = BT_SECURITY_LOW;
> conn->handle = __le16_to_cpu(ev->handle);
> - conn->state = BT_CONNECTED;
> + conn->state = BT_CONFIG;
>
> conn->le_conn_interval = le16_to_cpu(ev->interval);
> conn->le_conn_latency = le16_to_cpu(ev->latency);
> @@ -4524,7 +4555,18 @@ static void hci_le_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
> hci_debugfs_create_conn(conn);
> hci_conn_add_sysfs(conn);
>
> - hci_connect_cfm(conn, ev->status);
> + if (!ev->status) {
> + struct hci_cp_le_read_remote_features cp;
> +
> + cp.handle = __cpu_to_le16(conn->handle);
> +
> + hci_send_cmd(hdev, HCI_OP_LE_READ_REMOTE_FEATURES,
> + sizeof(cp), &cp);
Core Spec 4.0 allows this command to be send only when local role is master.
Shouldn't this be checked here (at least for 4.0 HW)? Otherwise we will drop
connection as slave if HW replies eg with command disallowed CS.
> +
> + hci_conn_hold(conn);
> + } else {
> + hci_connect_cfm(conn, ev->status);
> + }
>
> params = hci_pend_le_action_lookup(&hdev->pend_le_conns, &conn->dst,
> conn->dst_type);
> @@ -4826,6 +4868,31 @@ static void hci_le_adv_report_evt(struct hci_dev *hdev, struct sk_buff *skb)
> hci_dev_unlock(hdev);
> }
>
> +static void hci_le_remote_feat_complete_evt(struct hci_dev *hdev,
> + struct sk_buff *skb)
> +{
> + struct hci_ev_le_remote_feat_complete *ev = (void *)skb->data;
> + struct hci_conn *conn;
> +
> + BT_DBG("%s status 0x%2.2x", hdev->name, ev->status);
> +
> + hci_dev_lock(hdev);
> +
> + conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(ev->handle));
> + if (conn) {
> + if (!ev->status)
> + memcpy(conn->features[0], ev->features, 8);
> +
> + if (conn->state == BT_CONFIG) {
> + conn->state = BT_CONNECTED;
> + hci_connect_cfm(conn, ev->status);
> + hci_conn_drop(conn);
> + }
> + }
> +
> + hci_dev_unlock(hdev);
> +}
> +
> static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
> {
> struct hci_ev_le_ltk_req *ev = (void *) skb->data;
> @@ -4999,6 +5066,10 @@ static void hci_le_meta_evt(struct hci_dev *hdev, struct sk_buff *skb)
> hci_le_adv_report_evt(hdev, skb);
> break;
>
> + case HCI_EV_LE_REMOTE_FEAT_COMPLETE:
> + hci_le_remote_feat_complete_evt(hdev, skb);
> + break;
> +
> case HCI_EV_LE_LTK_REQ:
> hci_le_ltk_request_evt(hdev, skb);
> break;
>
--
Best regards,
Szymon Janc
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