Re: [RFCv0 03/21] Bluetooth: Add L2CAP create channel request handling.

[Andrei Emeltchenko <Andrei.Emeltchenko.news@gmail.com>]

Hi Mat,

On Wed, Jul 25, 2012 at 04:50:55PM -0700, Mat Martineau wrote:
> The L2CAP create channel request is very similar to an L2CAP connect
> request, but it has an additional parameter for the controller ID.  If
> the controller id is 0, the channel is set up on the BR/EDR controller
> (just like a connect request).  Using a valid high speed controller ID
> will cause the channel to be initially created on that high speed
> controller.  While the L2CAP data will be initially routed over the
> AMP controller, the L2CAP fixed signaling channel only uses BR/EDR.
> 
> When a create channel request is received for a high speed controller,
> a pending response is always sent first.  After the high speed
> physical and logical links are complete a success response will be
> sent.
> 
> Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
> ---
>  net/bluetooth/l2cap_core.c | 69 +++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 53 insertions(+), 16 deletions(-)
> 
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 24000ad..131d0da 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -3362,8 +3362,9 @@ static inline int l2cap_command_rej(struct l2cap_conn *conn, struct l2cap_cmd_hd
>  	return 0;
>  }
>  
> -static void __l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
> -			    u8 *data, u8 rsp_code, u8 amp_id)
> +static struct l2cap_chan *__l2cap_connect(struct l2cap_conn *conn,
> +					  struct l2cap_cmd_hdr *cmd,
> +					  u8 *data, u8 rsp_code, u8 chan_id)

Do you think chan_id is better then amp_id? At least for channel connect amp_id
looks better.

>  {
>  	struct l2cap_conn_req *req = (struct l2cap_conn_req *) data;
>  	struct l2cap_conn_rsp rsp;
> @@ -3390,7 +3391,7 @@ static void __l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
>  
>  	/* Check if the ACL is secure enough (if not SDP) */
>  	if (psm != __constant_cpu_to_le16(L2CAP_PSM_SDP) &&
> -				!hci_conn_check_link_mode(conn->hcon)) {
> +	    !hci_conn_check_link_mode(conn->hcon)) {

This change (and maybe some others may be merged with previous patch) ?

>  		conn->disc_reason = HCI_ERROR_AUTH_FAILURE;
>  		result = L2CAP_CR_SEC_BLOCK;
>  		goto response;
> @@ -3414,6 +3415,7 @@ static void __l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
>  	bacpy(&bt_sk(sk)->dst, conn->dst);
>  	chan->psm  = psm;
>  	chan->dcid = scid;
> +	chan->chan_id = chan_id;
>  
>  	bt_accept_enqueue(parent, sk);
>  
> @@ -3433,8 +3435,16 @@ static void __l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
>  				status = L2CAP_CS_AUTHOR_PEND;
>  				parent->sk_data_ready(parent, 0);
>  			} else {
> -				__l2cap_state_change(chan, BT_CONFIG);
> -				result = L2CAP_CR_SUCCESS;
> +				/* Force pending result for AMP controllers.
> +				 * The connection will succeed after the
> +				 * physical link is up. */
> +				if (chan_id) {
> +					__l2cap_state_change(chan, BT_CONNECT2);
> +					result = L2CAP_CR_PEND;
> +				} else {
> +					__l2cap_state_change(chan, BT_CONFIG);
> +					result = L2CAP_CR_SUCCESS;
> +				}
>  				status = L2CAP_CS_NO_INFO;
>  			}
>  		} else {
> @@ -3480,6 +3490,8 @@ sendresp:
>  					l2cap_build_conf_req(chan, buf), buf);
>  		chan->num_conf_req++;
>  	}
> +
> +	return chan;
>  }
>  
>  static int l2cap_connect_req(struct l2cap_conn *conn,
> @@ -3970,12 +3982,12 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn, struct l2cap_cm
>  	return 0;
>  }
>  
> -static inline int l2cap_create_channel_req(struct l2cap_conn *conn,
> -					struct l2cap_cmd_hdr *cmd, u16 cmd_len,
> -					void *data)
> +static int l2cap_create_channel_req(struct l2cap_conn *conn,
> +				    struct l2cap_cmd_hdr *cmd, u16 cmd_len,
> +				    void *data)
>  {
>  	struct l2cap_create_chan_req *req = data;
> -	struct l2cap_create_chan_rsp rsp;
> +	struct l2cap_chan *chan;
>  	u16 psm, scid;
>  
>  	if (cmd_len != sizeof(*req))
> @@ -3989,14 +4001,39 @@ static inline int l2cap_create_channel_req(struct l2cap_conn *conn,
>  
>  	BT_DBG("psm 0x%2.2x, scid 0x%4.4x, amp_id %d", psm, scid, req->amp_id);
>  
> -	/* Placeholder: Always reject */
> -	rsp.dcid = 0;
> -	rsp.scid = cpu_to_le16(scid);
> -	rsp.result = __constant_cpu_to_le16(L2CAP_CR_NO_MEM);
> -	rsp.status = __constant_cpu_to_le16(L2CAP_CS_NO_INFO);
> +	if (req->amp_id) {
> +		struct hci_dev *hdev;
>  
> -	l2cap_send_cmd(conn, cmd->ident, L2CAP_CREATE_CHAN_RSP,
> -		       sizeof(rsp), &rsp);
> +		/* Validate AMP controller id */
> +		hdev = hci_dev_get(req->amp_id);
> +		if (!hdev || !test_bit(HCI_UP, &hdev->flags)) {

Should we also check dev_type here? This might be second BREDR controller.

> +			struct l2cap_create_chan_rsp rsp;
> +
> +			rsp.dcid = 0;
> +			rsp.scid = cpu_to_le16(scid);
> +			rsp.result = L2CAP_CR_BAD_AMP;
> +			rsp.status = L2CAP_CS_NO_INFO;
> +
> +			l2cap_send_cmd(conn, cmd->ident, L2CAP_CREATE_CHAN_RSP,
> +				       sizeof(rsp), &rsp);
> +
> +			if (hdev)
> +				hci_dev_put(hdev);
> +
> +			return 0;
> +		}
> +
> +		hci_dev_put(hdev);
> +	}
> +
> +	chan = __l2cap_connect(conn, cmd, data, L2CAP_CREATE_CHAN_RSP,
> +			       req->amp_id);
> +
> +	/* Placeholder - uncomment when amp functions are available
> +	if (chan && req->amp_id &&
> +	    (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE))
> +		amp_accept_physical(conn, req->amp_id, sk);

I hope "sk" is a typo, we shall use "chan" here.

Best regards 
Andrei Emeltchenko