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Subject: Re: [PATCH v8 5/9] Bluetooth: Add BT_CODEC option for getsockopt for
 SCO socket
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <20210518104232.5431-5-kiran.k@intel.com>
Date:   Thu, 3 Jun 2021 16:35:26 +0200
Cc:     linux-bluetooth@vger.kernel.org, ravishankar.srivatsa@intel.com,
        chethan.tumkur.narayan@intel.com
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Message-Id: <C925CD9C-0CD3-493B-8A5B-42025D2655E6@holtmann.org>
References: <20210518104232.5431-1-kiran.k@intel.com>
 <20210518104232.5431-5-kiran.k@intel.com>
To:     Kiran K <kiran.k@intel.com>
Precedence: bulk

Hi Kiran,

> Add BT_CODEC option for getsockopt systemcall over SCO socket
> to expose the codecs supported by controller
> 
> Signed-off-by: Kiran K <kiran.k@intel.com>
> Reviewed-by: Chethan T N <chethan.tumkur.narayan@intel.com>
> Reviewed-by: Srivatsa Ravishankar <ravishankar.srivatsa@intel.com>
> ---
> include/net/bluetooth/bluetooth.h |  20 ++++++
> include/net/bluetooth/hci.h       |   4 ++
> net/bluetooth/sco.c               | 109 ++++++++++++++++++++++++++++++
> 3 files changed, 133 insertions(+)
> 
> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> index 9125effbf448..1840756958ce 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -153,6 +153,26 @@ struct bt_voice {
> 
> #define BT_SCM_PKT_STATUS	0x03
> 
> +#define BT_CODEC	19
> +
> +struct	bt_codec_caps {
> +	__u8	len;
> +	__u8	data[];
> +} __packed;
> +
> +struct bt_codec {
> +	__u8	id;
> +	__le16	cid;
> +	__le16	vid;
> +	__u8	data_path;
> +	__u8	num_caps;
> +} __packed;
> +
> +struct bt_codecs {
> +	__u8		num_codecs;
> +	struct bt_codec	codecs[];
> +} __packed;
> +

what is encapsulating what here?

> __printf(1, 2)
> void bt_info(const char *fmt, ...);
> __printf(1, 2)
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 731d48ca873a..9658600ae5de 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -2626,6 +2626,10 @@ static inline struct hci_sco_hdr *hci_sco_hdr(const struct sk_buff *skb)
> #define hci_iso_data_len(h)		((h) & 0x3fff)
> #define hci_iso_data_flags(h)		((h) >> 14)
> 
> +/* codec transport types */
> +#define TRANSPORT_BREDR		0x00
> +#define TRANSPORT_SCO_ESCO	0x01
> +

This is confusing. SCO_ESCO is also BREDR.

> /* le24 support */
> static inline void hci_cpu_to_le24(__u32 val, __u8 dst[3])
> {
> diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
> index 3bd41563f118..d66293d1cba4 100644
> --- a/net/bluetooth/sco.c
> +++ b/net/bluetooth/sco.c
> @@ -948,6 +948,11 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
> 	struct bt_voice voice;
> 	u32 phys;
> 	int pkt_status;
> +	struct codec_list *c;
> +	u8 num_codecs, i, __user *ptr;
> +	struct hci_dev *hdev;
> +	struct hci_codec_caps *caps;
> +	__u8	data_path;
> 
> 	BT_DBG("sk %p", sk);
> 
> @@ -1012,6 +1017,110 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
> 			err = -EFAULT;
> 		break;
> 
> +	case BT_CODEC:
> +		num_codecs = 0;
> +		len = 0;
> +
> +		hdev = hci_get_route(&sco_pi(sk)->dst, &sco_pi(sk)->src, BDADDR_BREDR);
> +

Remove extra empty line.

> +		if (!hdev) {
> +			err = -EBADFD;
> +			break;
> +		}
> +
> +		if (!test_bit(HCI_QUIRK_HFP_OFFLOAD_CODECS_SUPPORTED, &hdev->quirks)) {
> +			err = -EOPNOTSUPP;
> +			break;
> +		}
> +
> +		if (!hdev->get_data_path_id) {
> +			err = -EOPNOTSUPP;
> +			break;
> +		}

See it is pointless to check a quirk, you can use the callback for it.

> +
> +		hci_dev_lock(hdev);
> +		list_for_each_entry(c, &hdev->local_codecs, list) {
> +			if (c->transport != TRANSPORT_SCO_ESCO)
> +				continue;
> +			num_codecs++;
> +			for (i = 0, caps = c->caps; i < c->num_caps; i++) {
> +				len += 1 + caps->len;
> +				caps = (void *)&caps->data[caps->len];
> +			}
> +			len += sizeof(struct bt_codec);
> +		}
> +		hci_dev_unlock(hdev);
> +
> +		if (len > 255) {
> +			err = -ENOMEM;
> +			break;

I think this is the wrong error code. You need to indicate that size is wrong. ENOMEM really means that memory allocation failed.

> +		}
> +
> +		ptr = optval;
> +		if (put_user(num_codecs, ptr)) {
> +			err = -EFAULT;
> +			break;
> +		}
> +		ptr += sizeof(num_codecs);
> +
> +		hci_dev_lock(hdev);
> +		list_for_each_entry(c, &hdev->local_codecs, list) {
> +			if (c->transport != TRANSPORT_SCO_ESCO)
> +				continue;
> +
> +			if (put_user(c->id, ptr)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += sizeof(c->id);
> +
> +			if (put_user(c->cid, ptr)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += sizeof(c->cid);
> +
> +			if (put_user(c->vid, ptr)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += sizeof(c->vid);
> +
> +			err = hdev->get_data_path_id(hdev);
> +			if (err < 0) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			data_path = (__u8)err;
> +			if (put_user(data_path, ptr)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += sizeof(data_path);
> +
> +			if (put_user(c->num_caps, ptr)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += sizeof(c->num_caps);
> +
> +			len = 0;
> +			for (i = 0, caps = c->caps; i < c->num_caps; i++) {
> +				len += 1 + caps->len;
> +				caps = (void *)&caps->data[caps->len];
> +			}
> +
> +			if (len && copy_to_user(ptr, c->caps, len)) {
> +				err = -EFAULT;
> +				goto unlock;
> +			}
> +			ptr += len;
> +		}
> +unlock:
> +		hci_dev_unlock(hdev);
> +
> +		break;
> +
> 	default:
> 		err = -ENOPROTOOPT;
> 		break;

Regards

Marcel