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.Dd October 25, 2011
.Dt BT_DEV 3
.Os
.Sh NAME
.Nm bt_devaddr ,
.Nm bt_devname ,
.Nm bt_devenum ,
.Nm bt_devinfo ,
.Nm bt_devopen ,
.Nm bt_devsend ,
.Nm bt_devrecv ,
.Nm bt_devreq ,
.Nm bt_devfilter ,
.Nm bt_devfilter_pkt_set ,
.Nm bt_devfilter_pkt_clr ,
.Nm bt_devfilter_pkt_tst ,
.Nm bt_devfilter_evt_set ,
.Nm bt_devfilter_evt_clr ,
.Nm bt_devfilter_evt_tst ,
.Nm bt_devinquiry
.Nd Bluetooth device access routines
.Sh LIBRARY
.Lb libbluetooth
.Sh SYNOPSIS
.In bluetooth.h
.Ft int
.Fn bt_devaddr "const char *name" "bdaddr_t *bdaddr"
.Ft int
.Fn bt_devname "char *name" "const bdaddr_t *bdaddr"
.Ft int
.Fn bt_devenum "int (*cb)(int, const struct bt_devinfo *, void *)" "void *arg"
.Ft int
.Fn bt_devinfo "const char *name" "struct bt_devinfo *info"
.Ft int
.Fn bt_devopen "const char *name" "int flags"
.Ft ssize_t
.Fn bt_devsend "int s" "uint16_t opcode" "void *param" "size_t plen"
.Ft ssize_t
.Fn bt_devrecv "int s" "void *buf" "size_t size" "time_t timeout"
.Ft int
.Fn bt_devreq "int s" "struct bt_devreq *req" "time_t timeout"
.Ft int
.Fn bt_devfilter "int s" "const struct bt_devfilter *new" "struct bt_devfilter *old"
.Ft void
.Fn bt_devfilter_pkt_set "struct bt_devfilter *filter" "uint8_t type"
.Ft void
.Fn bt_devfilter_pkt_clr "struct bt_devfilter *filter" "uint8_t type"
.Ft int
.Fn bt_devfilter_pkt_tst "const struct bt_devfilter *filter" "uint8_t type"
.Ft void
.Fn bt_devfilter_evt_set "struct bt_devfilter *filter" "uint8_t event"
.Ft void
.Fn bt_devfilter_evt_clr "struct bt_devfilter *filter" "uint8_t event"
.Ft int
.Fn bt_devfilter_evt_tst "const struct bt_devfilter *filter" "uint8_t event"
.Ft int
.Fn bt_devinquiry "const char *name" "time_t timeout" "int max_rsp" "struct bt_devinquiry **iip"
.Sh DESCRIPTION
These routines are designed to provide access to locally configured Bluetooth
devices in an operating system independent manner via a socket providing access
to Bluetooth HCI packets.
.Sh FUNCTIONS
.Bl -tag -width 4n
.It Fn bt_devaddr "name" "bdaddr"
Return a Bluetooth device address.
.Fn bt_devaddr
will return 1 if the NUL-terminated
.Fa name
string refers to a Bluetooth device present in the system, otherwise 0.
The name may be given as a device name
.Pq eg Qo ubt0 Qc
or Bluetooth device address
.Pq eg Qo 00:11:22:33:44:55 Qc
and the actual device address will be written to
.Fa bdaddr
if not
.Dv NULL .
.It Fn bt_devname "name" "bdaddr"
Return a Bluetooth device name.
.Fn bt_devname
returns 1 if the
.Fa bdaddr
refers to a Bluetooth device present in the system, otherwise 0.
The
.Fa name
buffer, if given, should have space for at least
.Dv HCI_DEVNAME_SIZE
bytes and the string will be NUL-terminated.
.It Fn bt_devenum "cb" "arg"
Enumerate Bluetooth devices present in the system.
For each device found, the
.Fa cb
function
.Pq if not Dv NULL
will be called with the
.Fa arg
argument provided, a fully populated
.Ft bt_devinfo
structure and, where the device is enabled, a socket handle as returned by
.Fn bt_devopen .
The callback function can halt the enumeration by returning a
non-zero value, and
.Fn bt_devenum
returns the number of successfully enumerated devices.
.It Fn bt_devinfo "name" "info"
Obtain information from a Bluetooth device present in the system.
The
.Fa info
argument is a pointer to a
.Ft bt_devinfo
structure into which information about device
.Fa name
is placed.
The
.Ft bt_devinfo
structure contains at least the following members:
.Bd -literal
        char        devname[HCI_DEVNAME_SIZE];
        int         enabled;    /* device is enabled */

        /* device information */
        bdaddr_t    bdaddr;
        uint8_t     features[HCI_FEATURES_SIZE];
        uint16_t    acl_size;   /* max ACL data size */
        uint16_t    acl_pkts;   /* total ACL packet buffers */
        uint16_t    sco_size;   /* max SCO data size */
        uint16_t    sco_pkts;   /* total SCO packet buffers */

        /* flow control */
        uint16_t    cmd_free;   /* available CMD packet buffers */
        uint16_t    acl_free;   /* available ACL packet buffers */
        uint16_t    sco_free;   /* available SCO packet buffers */

        /* statistics */
        uint32_t    cmd_sent;
        uint32_t    evnt_recv;
        uint32_t    acl_recv;
        uint32_t    acl_sent;
        uint32_t    sco_recv;
        uint32_t    sco_sent;
        uint32_t    bytes_recv;
        uint32_t    bytes_sent;

        /* device settings */
        uint16_t    link_policy_info;
        uint16_t    packet_type_info;
        uint16_t    role_switch_info;
.Ed
.Lp
Because a Bluetooth device must be enabled in order to retrieve
information, the
.Fa enabled
flag should be tested to be non-zero before relying on further data.
.It Fn bt_devopen "name" "flags"
Return a Bluetooth HCI socket handle bound and connected to the
named Bluetooth device or, if
.Fa name
is
.Dv NULL ,
enabled to receive packets from any device.
The socket should be closed using
.Xr close 2
after use.
Any combination of the following
.Fa flags
may be used to pre-set the socket options:
.Bl -tag -width ".Dv BTOPT_DIRECTION"
.It Dv BTOPT_DIRECTION
Enable control messages on each packet indicating the direction of travel.
.It Dv BTOPT_TIMESTAMP
Enable control messages providing packet timestamps.
.El
.Lp
The default filter on the socket will only allow the HCI Event packets
.Qq Command Status
and
.Qq Command Complete
to be received.
.It Fn bt_devsend "s" "opcode" "param" "plen"
Send an HCI command packet on the socket
.Fa s .
The
.Fa opcode
should be in host byte order and the
.Fa param
and
.Fa plen
arguments can be used to provide command parameter data.
.Fn bt_devsend
will return the number of bytes successfully written.
.It Fn bt_devrecv "s" "buf" "size" "timeout"
Receive a single HCI packet on the socket
.Fa s .
.Fn bt_devrecv
will return the number of bytes successfully received unless the
provided buffer could not contain the entire packet, or if a timeout was
requested with a non-negative
.Fa timeout
value.
.It Fn bt_devreq "s" "req" "timeout"
Make an HCI request on the socket
.Fa s .
The
.Fa req
argument is a pointer to a
.Ft bt_devreq
structure, defined as:
.Bd -literal -offset indent
struct bt_devreq {
        uint16_t        opcode;
        uint8_t         event;
        void           *cparam;
        size_t          clen;
        void           *rparam;
        size_t          rlen;
};
.Ed
.Lp
.Fn bt_devreq
sends an HCI command packet with the given
.Fa opcode
and command parameters of
.Fa clen
bytes at
.Fa cparam
then waits up to
.Fa timeout
seconds for the command to return a
.Qq Command Complete
event.
In the case where the command returns
.Qq Command Status
and an additional event, and where the status indicates
that the command is in progress,
.Fn bt_devreq
will wait for the additional
.Fa event
specified in the request.
If required, any response will be copied into the buffer of
.Fa rlen
bytes at
.Fa rparam ,
and
.Fa rlen
will be adjusted to indicate the number of bytes stored.
.Fn bt_devreq
temporarily modifies the socket filter.
.It Fn bt_devfilter "s" "new" "old"
Update or extract the packet filter on HCI socket
.Fa s .
Filters can be set to indicate packet types
.Pq Commands, Events, ACL and SCO data ,
and individual event IDs.
Where
.Fa old
is given, the currently set filter will be extracted first, then if
.Fa new
is given, the filter will be updated.
.It Fn bt_devfilter_pkt_set "filter" "type"
Set packet
.Fa type
in
.Fa filter .
.It Fn bt_devfilter_pkt_clr "filter" "type"
Clear packet
.Fa type
from
.Fa filter .
.It Fn bt_devfilter_pkt_tst "filter" "type"
Test if
.Fa filter
has packet
.Fa type
set.
.It Fn bt_devfilter_evt_set "filter" "event"
Set
.Fa event
ID in
.Fa filter .
.It Fn bt_devfilter_evt_clr "filter" "event"
Clear
.Fa event
ID from
.Fa filter .
.It Fn bt_devfilter_evt_tst "filter" "event"
Test if
.Fa filter
has
.Fa event
ID set.
.It Fn bt_devinquiry "name" "timeout" "max_rsp" "iip"
Perform a Bluetooth Inquiry using the device
.Fa name ,
or the first available device if
.Dv NULL
is passed.
The inquiry length will be
.Fa timeout
seconds, and the number of responses
.Pq up to a limit of Fa max_rsp
will be returned.
A pointer to an array of
.Ft bt_devinquiry
structures, defined as:
.Bd -literal -offset indent
struct bt_devinquiry {
        bdaddr_t        bdaddr;
        uint8_t         pscan_rep_mode;
        uint8_t         pscan_period_mode;
        uint8_t         dev_class[3];
        uint16_t        clock_offset;
        int8_t          rssi;
        uint8_t         data[240];
};
.Ed
.Lp
will be stored in the location given by
.Fa iip
and this should be released after use with
.Xr free 3 .
.El
.Sh RETURN VALUES
These Bluetooth device access routines return \-1 on failure, and
.Va errno
will be set to indicate the error.
.Sh ERRORS
In addition to errors returned by the standard C library IO functions,
the following errors may be indicated by device access routines.
.Bl -tag -offset indent -width ".Bq Er ETIMEDOUT"
.It Bq Er EINVAL
A provided function argument was not valid.
.It Bq Er EIO
A device response was not properly understood.
.It Bq Er ETIMEDOUT
An operation exceeded the given time limit.
.El
.Sh SEE ALSO
.Xr bluetooth 3
.Sh HISTORY
The Bluetooth device access API was created by
.An Maksim Yevmenkin
and first appeared in
.Fx .
This implementation written for
.Nx
by
.An Iain Hibbert .