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.Dd November 20, 2007
.Dt BLUETOOTH 9
.Os
.Sh NAME
.Nm BLUETOOTH
.Nd Bluetooth Device/Protocol API
.Sh SYNOPSIS
.In netbt/bluetooth.h
.In netbt/hci.h
.In netbt/l2cap.h
.In netbt/rfcomm.h
.Ft struct hci_unit *
.Fn hci_attach "const struct hci_if *hci_if" "device_t dev" "uint16_t flags"
.Ft void
.Fn hci_detach "struct hci_unit *unit"
.Ft void
.Fn hci_input_event "struct hci_unit *unit" "struct mbuf *m"
.Ft void
.Fn hci_input_acl "struct hci_unit *unit" "struct mbuf *m"
.Ft void
.Fn hci_input_sco "struct hci_unit *unit" "struct mbuf *m"
.Ft int
.Fn btproto_attach "btproto_handle *" "const struct btproto *proto" "void *ref"
.Ft int
.Fn btproto_bind "btproto_handle" "struct sockaddr_bt *addr"
.Ft int
.Fn btproto_sockaddr "btproto_handle" "struct sockaddr_bt *addr"
.Ft int
.Fn btproto_connect "btproto_handle" "struct sockaddr_bt *addr"
.Ft int
.Fn btproto_peeraddr "btproto_handle" "struct sockaddr_bt *addr"
.Ft int
.Fn btproto_disconnect "btproto_handle" "int linger"
.Ft int
.Fn btproto_detach "btproto_handle *"
.Ft int
.Fn btproto_listen "btproto_handle"
.Ft int
.Fn btproto_send "btproto_handle" "struct mbuf *mbuf"
.Ft int
.Fn btproto_rcvd "btproto_handle" "size_t space"
.Ft int
.Fn btproto_setopt "btproto_handle" "int optarg" "void *arg"
.Ft int
.Fn btproto_getopt "btproto_handle" "int optarg" "void *arg"
.Sh DESCRIPTION
The Bluetooth Protocol Stack provides socket based access to Bluetooth
Devices.
This document describes device driver access to the stack from
below, and also the general Bluetooth Protocol/Service API for layering
above existing Bluetooth Protocols.
.Sh DATA TYPES
Device drivers attaching to the Bluetooth Protocol Stack should pass a
pointer to a
.Fa struct hci_if
defined in
.In netbt/hci.h
containing the driver information as follows:
.Bd -literal
struct hci_if {
	int	(*enable)(device_t);
	void	(*disable)(device_t);
	void	(*output_cmd)(device_t, struct mbuf *);
	void	(*output_acl)(device_t, struct mbuf *);
	void	(*output_sco)(device_t, struct mbuf *);
	void	(*get_stats)(device_t, struct bt_stats *, int);
	int	ipl;
};
.Ed
.Pp
Statistics counters should be updated by the device after packets have
been transmitted or received, or when errors occur.
.Bd -literal
struct bt_stats {
	uint32_t	err_tx;
	uint32_t	err_rx;
	uint32_t	cmd_tx;
	uint32_t	evt_rx;
	uint32_t	acl_tx;
	uint32_t	acl_rx;
	uint32_t	sco_tx;
	uint32_t	sco_rx;
	uint32_t	byte_tx;
	uint32_t	byte_rx;
};
.Ed
.Pp
Bluetooth Protocol layers attaching above the Bluetooth Protocol Stack
will make use of the
.Fa struct btproto
data type, which is defined in
.In netbt/bluetooth.h
and contains the following function callbacks which
should be initialized by the protocol layer before attaching to the
protocol which it uses:
.Bd -literal
struct btproto {
	void (*connecting)(void *);
	void (*connected)(void *);
	void (*disconnected)(void *, int);
	void *(*newconn)(void *, struct sockaddr_bt *, struct sockaddr_bt *);
	void (*complete)(void *, int);
	void (*linkmode)(void *, int);
	void (*input)(void *, struct mbuf *);
};
.Ed
.Sh FUNCTIONS
The following functions are related to the Bluetooth Device API.
.Bl -tag -width XXXX
.It Fn hci_attach "hci_if" "dev"
Attach Bluetooth HCI device
.Ar dev
to the protocol stack in the manner described by
.Ar hci_if .
Driver quirks may be registered by passing the corresponding
.Dv BTF_xxxx
flag in the
.Ar flags
argument.
.Pp
.Fn hci_attach
will return a
.Fa struct hci_unit
handle to be passed to the protocol stack in other calls.
.It Fn hci_detach "unit"
Detach Bluetooth HCI
.Ar unit
from the device.
.It Fn hci_input_event "unit" "mbuf"
This function should be called by the device when it has an event
packet to present to the protocol stack.
It may be called from an interrupt routine at the
.Fa ipl
value given in the
.Ar hci_if
descriptor.
.It Fn hci_input_acl "unit" "mbuf"
This function should be called by the device when it has an ACL data
packet to present to the protocol stack.
It may be called from an interrupt routine at the
.Fa ipl
value given in the
.Ar hci_if
descriptor.
.It Fn hci_input_sco "unit" "mbuf"
This function should be called by the device when it has an SCO data
packet to present to the protocol stack.
It may be called from an interrupt routine at the
.Fa ipl
value given in the
.Ar hci_if
descriptor.
.It Fn "(*enable)" "dev"
This will be called when the protocol stack wishes to enable the device.
.It Fn "(*disable)" "dev"
This will be called when the protocol stack wishes to disable the device.
.It Fn "(*output_cmd)" "dev" "mbuf"
Will be called to output command packets on the device.
The device is responsible for arbitrating access to the output queue, and
output commands should be sent asynchronously.
The device owns the
.Ar mbuf
and should release it when sent.
.It Fn "(*output_acl)" "dev" "mbuf"
Will be called to output ACL data packets on the device.
The device is responsible for arbitrating access to the output queue, and
ACL data packets should be sent asynchronously.
The device owns the
.Ar mbuf
and should release it when sent.
.It Fn "(*output_sco)" "dev" "mbuf"
Will be called to output SCO data packets on the device.
The device is responsible for arbitrating access to the output queue, and
SCO data packets should be sent asynchronously.
When the SCO data packet has been placed on the device and the
.Ar mbuf
is no longer required, it should be returned to the Bluetooth protocol
stack via the
.Fn hci_complete_sco
call.
.It Fn "(*get_stats)" "dev" "dest" "flush"
Will be called when IO statistics are requested.
The
.Fa bt_stats
structure
.Ar dest
should be filled in, and if the
.Ar flush
argument is true, statistics should be reset.
.El
.Pp
The following function definitions are related to the Bluetooth Protocol API.
Note that the "btproto" prefix is representative only, the protocol being
used will have a more specific prefix with prototypes being declared in
the appropriate
.In netbt/btproto.h
file.
.Bl -tag -width XXXX
.It Fn btproto_attach "handle_ptr" "proto" "ref"
Allocate and initialize a new protocol object at the
.Ar handle_ptr
address that should subsequently be passed into the other functions.
.Ar proto
is a pointer to the
.Fa btproto
structure as described above containing relevant callbacks, and
.Ar ref
is the argument that will be supplied to those calls.
.It Fn btproto_bind "handle" "addr"
Set the local address of the protocol object described by
.Ar handle
to
.Ar addr .
.It Fn btproto_sockaddr "handle" "addr"
Copy the local address of the protocol object described by
.Ar handle
into
.Ar addr
.It Fn btproto_connect "handle" "addr"
Initiate a connection by the protocol object described by
.Ar handle
to the remote device described by
.Ar addr .
This will result in a call to either
.Fn proto->connected
or
.Fn proto->disconnected ,
and optionally
.Fn proto->connecting
with the appropriate reference as given to
.Fn btproto_attach .
.It Fn btproto_peeraddr "handle" "addr"
Copy the remote address of the protocol object described by
.Ar handle
into
.Ar addr .
.It Fn btproto_disconnect "handle" "linger"
Schedule a disconnection by the protocol object described by
.Ar handle .
This will result in a call to
.Fn proto->disconnected
with the appropriate reference when the connection is torn
down.
If linger is zero, the disconnection will be initiated
immediately and any outstanding data may be lost.
.It Fn btproto_detach "handle_ptr"
Detach the protocol object described by the value in the location of
.Ar handle_ptr ,
and free any related memory.
The pointer in the location is cleared.
.It Fn btproto_listen "handle"
Use the protocol object described by
.Ar handle
as a listening post.
This will result in calls to the
.Fn proto->newconn
function when incoming connections are detected.
.It Fn btproto_send "handle" "mbuf"
Send data on the connection described by the protocol object.
.It Fn btproto_rcvd "handle" "space"
Indicate to the protocol that
.Ar space
is now available in the input buffers so that flow control may be
deasserted.
This should also be called to indicate initial buffer space.
Note that
.Ar space
is an absolute value.
.It Fn btproto_setopt "handle" "optarg" "arg"
Set options on the protocol object described by
.Ar handle .
.It Fn btproto_getopt "handle" "optarg" "arg"
Get options for the protocol object described by
.Ar handle .
.It Fn "(*connecting)" "ref"
This function will be called when the protocol receives information
that the connection described by
.Ar ref
is pending.
.It Fn "(*connected)" "ref"
This function will be called when the connection described by
.Ar ref
is successful and indicates that data may now be sent.
.It Fn "(*disconnected)" "ref" "error"
This function will be called when the connection described by
.Ar ref
is disconnected.
.It Fn "*(*newconn)" "ref" "laddr" "raddr"
This function will be called when the protocol receives a new incoming
connection on the local device described by
.Ar laddr
from the remote device described by
.Ar raddr .
The protocol should decide if it wishes to accept the connection and
should attach and return a new instance of the relevant protocol handle
or NULL.
.It Fn "(*complete)" "ref" "count"
This function will be called when the protocol has completed sending
data.
Complete will usually mean that the data has successfully left
the device though for guaranteed protocols it can mean that the data
has arrived at the other end and been acknowledged, and that
.Ar count
amount of data can be removed from the socket buffer.
The units of the
.Ar count
value will be dependent on the protocol being used (e.g. RFCOMM is bytes,
but L2CAP is packets)
.It Fn "(*linkmode)" "ref" "mode"
This function will be called for established connections, when the link mode
of the baseband link has changed.
.Ar mode
is the new mode.
.It Fn "(*input)" "ref" "mbuf"
This function is called to supply new data on the connection described by
.Ar ref .
.El
.Sh CODE REFERENCES
The Bluetooth Protocol Stack is contained in the
.Pa sys/netbt
directory.
.Pp
The Bluetooth Device API as described above is contained
in the
.Pa sys/netbt/hci_unit.c
file.
.Pp
For examples of the Bluetooth Protocol API see the interaction between
the L2CAP upper layer in
.Pa sys/netbt/l2cap_upper.c
and either the L2CAP socket layer in
.Pa sys/netbt/l2cap_socket.c
or the
.Xr bthidev 4
pseudo-device in
.Pa sys/dev/bluetooth/bthidev.c .
.Pp
Also, the RFCOMM upper layer in
.Pa sys/netbt/rfcomm_upper.c
and the RFCOMM socket layer in
.Pa sys/netbt/rfcomm_socket.c .
.Sh SEE ALSO
.Xr bluetooth 4 ,
.Xr bt3c 4 ,
.Xr bthidev 4 ,
.Xr ubt 4
.Sh HISTORY
This Bluetooth Protocol Stack was written for
.Nx 4.0
by
.An Iain Hibbert ,
under the sponsorship of Itronix, Inc.