[5/6] Bluetooth: ISO: use correct CIS order in Set CIG Parameters event

The order of CIS handle array in Set CIG Parameters response shall match
the order of the CIS_ID array in the command (Core v5.3 Vol 4 Part E Sec
7.8.97).  We send CIS_IDs mainly in the order of increasing CIS_ID (but
with "last" CIS first if it has fixed CIG_ID).  In handling of the
reply, we currently assume this is also the same as the order of
hci_conn in hdev->conn_hash, but that is not true.

Match the correct hci_conn to the correct handle by matching them based
on the CIG+CIS combination.  The CIG+CIS combination shall be unique for
ISO_LINK hci_conn at state >= BT_BOUND, which we maintain in
hci_le_set_cig_params.

Fixes: 26afbd826ee3 ("Bluetooth: Add initial implementation of CIS connections")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
---
 net/bluetooth/hci_event.c | 66 +++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 16 deletions(-)

Hi Pauli,

On Sun, May 28, 2023 at 10:49 AM Pauli Virtanen <pav@iki.fi> wrote:
>
> The order of CIS handle array in Set CIG Parameters response shall match
> the order of the CIS_ID array in the command (Core v5.3 Vol 4 Part E Sec
> 7.8.97).  We send CIS_IDs mainly in the order of increasing CIS_ID (but
> with "last" CIS first if it has fixed CIG_ID).  In handling of the
> reply, we currently assume this is also the same as the order of
> hci_conn in hdev->conn_hash, but that is not true.
>
> Match the correct hci_conn to the correct handle by matching them based
> on the CIG+CIS combination.  The CIG+CIS combination shall be unique for
> ISO_LINK hci_conn at state >= BT_BOUND, which we maintain in
> hci_le_set_cig_params.
>
> Fixes: 26afbd826ee3 ("Bluetooth: Add initial implementation of CIS connections")
> Signed-off-by: Pauli Virtanen <pav@iki.fi>
> ---
>  net/bluetooth/hci_event.c | 66 +++++++++++++++++++++++++++++----------
>  1 file changed, 50 insertions(+), 16 deletions(-)
>
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index d00ef6e3fc45..71d8f1442287 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -3804,43 +3804,77 @@ static u8 hci_cc_le_set_cig_params(struct hci_dev *hdev, void *data,
>                                    struct sk_buff *skb)
>  {
>         struct hci_rp_le_set_cig_params *rp = data;
> +       struct hci_cp_le_set_cig_params *cp;
>         struct hci_conn *conn;
> -       int i = 0;
> +       u16 handles[0x1f];
> +       int num_handles;
> +       u8 status = rp->status;
> +       int i;
>
>         bt_dev_dbg(hdev, "status 0x%2.2x", rp->status);
>
> +       cp = hci_sent_cmd_data(hdev, HCI_OP_LE_SET_CIG_PARAMS);
> +       if (!cp || rp->num_handles != cp->num_cis || rp->cig_id != cp->cig_id ||
> +           rp->num_handles > ARRAY_SIZE(handles)) {
> +               bt_dev_err(hdev, "unexpected Set CIG Parameters response data");
> +               status = HCI_ERROR_UNSPECIFIED;
> +       }
> +
>         hci_dev_lock(hdev);
>
> -       if (rp->status) {
> +       if (status) {
>                 while ((conn = hci_conn_hash_lookup_cig(hdev, rp->cig_id))) {
>                         conn->state = BT_CLOSED;
> -                       hci_connect_cfm(conn, rp->status);
> +                       hci_connect_cfm(conn, status);
>                         hci_conn_del(conn);
>                 }
>                 goto unlock;
>         }
>
> +       /* BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E page 2553
> +        *
> +        * If the Status return parameter is zero, then the Controller shall
> +        * set the Connection_Handle arrayed return parameter to the connection
> +        * handle(s) corresponding to the CIS configurations specified in
> +        * the CIS_IDs command parameter, in the same order.
> +        */
> +
> +       num_handles = rp->num_handles;
> +       for (i = 0; i < rp->num_handles; ++i)
> +               handles[i] = __le16_to_cpu(rp->handle[i]);

Using the request is a good idea but the code below sounds a little
too complicated, can we just lookup the hci_conn by cig/cis at this
point using the request parameters and just assign the handle in a
single loop?

>         rcu_read_lock();
>
>         list_for_each_entry_rcu(conn, &hdev->conn_hash.list, list) {
> -               if (conn->type != ISO_LINK ||
> -                   conn->iso_qos.ucast.cig != rp->cig_id ||
> -                   conn->state == BT_CONNECTED)
> +               if (conn->type != ISO_LINK || !bacmp(&conn->dst, BDADDR_ANY) ||
> +                   (conn->state != BT_BOUND && conn->state != BT_CONNECT) ||
> +                   conn->iso_qos.ucast.cig != rp->cig_id)
>                         continue;
>
> -               conn->handle = __le16_to_cpu(rp->handle[i++]);
> +               for (i = 0; i < rp->num_handles; ++i) {
> +                       if (handles[i] == HCI_CONN_HANDLE_UNSET)
> +                               continue;
> +                       if (conn->iso_qos.ucast.cis != cp->cis[i].cis_id)
> +                               continue;
>
> -               bt_dev_dbg(hdev, "%p handle 0x%4.4x parent %p", conn,
> -                          conn->handle, conn->parent);
> +                       conn->handle = handles[i];
> +                       handles[i] = HCI_CONN_HANDLE_UNSET;
> +                       --num_handles;
>
> -               /* Create CIS if LE is already connected */
> -               if (conn->parent && conn->parent->state == BT_CONNECTED) {
> -                       rcu_read_unlock();
> -                       hci_le_create_cis(conn);
> -                       rcu_read_lock();
> +                       bt_dev_dbg(hdev, "%p handle 0x%4.4x parent %p",
> +                                  conn, conn->handle, conn->parent);
> +
> +                       /* Create CIS if LE is already connected */
> +                       if (conn->parent &&
> +                           conn->parent->state == BT_CONNECTED) {
> +                               rcu_read_unlock();
> +                               hci_le_create_cis(conn);
> +                               rcu_read_lock();
> +                       }
> +
> +                       break;
>                 }
> -
> -               if (i == rp->num_handles)
> +               if (!num_handles)
>                         break;
>         }
>
> --
> 2.40.1
>