lib/libsdp/sdp.3

.\" Copyright (c) 2003 Maksim Yevmenkin <m_evmenkin@yahoo.com>
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.\" $Id: sdp.3,v 1.1 2003/09/07 20:34:19 max Exp $
.\"
.Dd April 30, 2018
.Dt SDP 3
.Os
.Sh NAME
.Nm SDP_GET8 ,
.Nm SDP_GET16 ,
.Nm SDP_GET32 ,
.Nm SDP_GET64 ,
.Nm SDP_GET128 ,
.Nm SDP_GET_UUID128 ,
.Nm SDP_PUT8 ,
.Nm SDP_PUT16 ,
.Nm SDP_PUT32 ,
.Nm SDP_PUT64 ,
.Nm SDP_PUT128 ,
.Nm SDP_PUT_UUID128 ,
.Nm sdp_open ,
.Nm sdp_open_local ,
.Nm sdp_close ,
.Nm sdp_error ,
.Nm sdp_get_lcaddr ,
.Nm sdp_search ,
.Nm sdp_attr2desc ,
.Nm sdp_uuid2desc
.Nd Bluetooth SDP routines
.Sh LIBRARY
.Lb libsdp
.Sh SYNOPSIS
.In bluetooth.h
.In sdp.h
.Fn SDP_GET8 "b" "cp"
.Fn SDP_GET16 "s" "cp"
.Fn SDP_GET32 "l" "cp"
.Fn SDP_GET64 "l" "cp"
.Fn SDP_GET128 "l" "cp"
.Fn SDP_GET_UUID128 "l" "cp"
.Fn SDP_PUT8 "b" "cp"
.Fn SDP_PUT16 "s" "cp"
.Fn SDP_PUT32 "l" "cp"
.Fn SDP_PUT64 "l" "cp"
.Fn SDP_PUT128 "l" "cp"
.Fn SDP_PUT_UUID128 "l" "cp"
.Ft "void *"
.Fn sdp_open "bdaddr_t const *l" "bdaddr_t const *r"
.Ft "void *"
.Fn sdp_open_local "char const *control"
.Ft int32_t
.Fn sdp_close "void *xs"
.Ft int32_t
.Fn sdp_error "void *xs"
.Ft int32_t
.Fn sdp_get_lcaddr "void *xs" "bdaddr_t *l"
.Ft int32_t
.Fo sdp_search
.Fa "void *xs" "uint32_t plen" "uint16_t const *pp" "uint32_t alen"
.Fa "uint32_t const *ap" "uint32_t vlen" "sdp_attr_t *vp"
.Fc
.Ft "char const * const"
.Fn sdp_attr2desc "uint16_t attr"
.Ft "char const * const"
.Fn sdp_uuid2desc "uint16_t uuid"
.Ft int32_t
.Fo sdp_register_service
.Fa "void *xss" "uint16_t uuid" "bdaddr_p const bdaddr" "uint8_t const *data"
.Fa "uint32_t datalen" "uint32_t *handle"
.Fc
.Ft int32_t
.Fn sdp_unregister_service "void *xss" "uint32_t handle"
.Ft int32_t
.Fo sdp_change_service
.Fa "void *xss" "uint32_t handle" "uint8_t const *data" "uint32_t datalen"
.Fc
.Sh DESCRIPTION
The
.Fn SDP_GET8 ,
.Fn SDP_GET16 ,
.Fn SDP_GET32 ,
.Fn SDP_GET64
and
.Fn SDP_GET128
macros are used to get byte, short, long, long long and 128-bit integer
from the buffer pointed by
.Fa cp
pointer.
The pointer is automatically advanced.
.Pp
The
.Fn SDP_PUT8 ,
.Fn SDP_PUT16 ,
.Fn SDP_PUT32 ,
.Fn SDP_PUT64
and
.Fn SDP_PUT128
macros are used to put byte, short, long, long long and 128-bit integer
into the buffer pointed by
.Fa cp
pointer.
The pointer is automatically advanced.
.Pp
.Fn SDP_GET_UUID128
and
.Fn SDP_PUT_UUID128
macros are used to get and put 128-bit UUID into the buffer pointed by
.Fa cp
pointer.
The pointer is automatically advanced.
.Pp
The
.Fn sdp_open
and
.Fn sdp_open_local
functions each return a pointer to an opaque object describing SDP session.
The
.Fa l
argument passed to
.Fn sdp_open
function should point to a source BD_ADDR.
If source BD_ADDR is
.Dv NULL
then source address
.Dv NG_HCI_BDADDR_ANY
is used.
The
.Fa r
argument passed to
.Fn sdp_open
function should point to a
.Pf non- Dv NULL
remote BD_ADDR.
Remote BD_ADDR cannot be
.Dv NG_HCI_BDADDR_ANY .
The
.Fn sdp_open_local
function takes path to the control socket and opens a connection to a local
SDP server.
If path to the control socket is
.Dv NULL
then default
.Pa /var/run/sdp
path will be used.
.Pp
The
.Fn sdp_close
function terminates active SDP session and deletes SDP session object.
The
.Fa xs
parameter should point to a valid SDP session object created with
.Fn sdp_open
or
.Fn sdp_open_local .
.Pp
The
.Fn sdp_error
function returns last error that is stored inside SDP session object.
The
.Fa xs
parameter should point to a valid SDP session object created with
.Fn sdp_open
or
.Fn sdp_open_local .
The error value returned can be converted to a human readable message by
calling
.Xr strerror 3
function.
.Pp
The
.Fn sdp_get_lcaddr
function returns the SDP session actual source BD_ADDR.
The
.Fa xs
parameter should point to a valid SDP session object created with
.Fn sdp_open .
The
.Fa l
parameter should point to a buffer in which the value for the requested BD_ADDR
is to be returned.
.Fn sdp_get_lcaddr
function is useful if the current SDP session has been opened with the
.Dv NG_HCI_BDADDR_ANY
value passed as a source address.
.Pp
The
.Fn sdp_search
function is used to perform SDP Service Search Attribute Request.
The
.Fa xs
parameter should point to a valid SDP session object created with
.Fn sdp_open
or
.Fn sdp_open_local .
The
.Fa pp
parameter is a Service Search Pattern - an array of one or more Service
Class IDs.
The maximum number of Service Class IDs in the array is 12.
The
.Fa plen
parameter is the length of the Service Search pattern.
The
.Fa ap
parameter is an Attribute ID Range List - an array of one or more SDP Attribute
ID Range.
Each attribute ID Range is encoded as a 32-bit unsigned integer data
element, where the high order 16 bits are interpreted as the beginning
attribute ID of the range and the low order 16 bits are interpreted as the
ending attribute ID of the range.
The attribute IDs contained in the Attribute ID Ranges List must be listed in
ascending order without duplication of any attribute ID values.
Note that all attributes may be requested by specifying a range of
0x0000-0xFFFF.
The
.Fa alen
parameter is the length of the Attribute ID Ranges List.
The
.Fn SDP_ATTR_RANGE "lo" "hi"
macro can be used to prepare Attribute ID Range.
The
.Fa vp
parameter should be an array of
.Vt sdp_attr_t
structures.
Each
.Vt sdp_attr_t
structure describes single SDP attribute and defined as follows:
.Bd -literal -offset indent
struct sdp_attr {
        uint16_t        flags;
#define SDP_ATTR_OK             (0 << 0)
#define SDP_ATTR_INVALID        (1 << 0)
#define SDP_ATTR_TRUNCATED      (1 << 1)
        uint16_t        attr;  /* SDP_ATTR_xxx */
        uint32_t        vlen;  /* length of the value[] in bytes */
        uint8_t        *value; /* base pointer */
};
typedef struct sdp_attr         sdp_attr_t;
typedef struct sdp_attr *       sdp_attr_p;
.Ed
.Pp
The caller of the
.Fn sdp_search
function is expected to prepare the array of
.Vt sdp_attr
structures and for each element of the array both
.Va vlen
and
.Va value
must be set.
The
.Fn sdp_search
function will fill each
.Vt sdp_attr_t
structure with attribute and value, i.e., it will set
.Va flags ,
.Va attr
and
.Va vlen
fields.
The actual value of the attribute will be copied into
.Va value
buffer.
Note: attributes are returned in the order they appear in the Service Search
Attribute Response.
SDP server could return several attributes for the same record.
In this case the order of the attributes will be: all attributes for the first
records, then all attributes for the second record etc.
.Pp
The
.Fn sdp_attr2desc
and
.Fn sdp_uuid2desc
functions each take a numeric attribute ID/UUID value and convert it to a
human readable description.
.Pp
The
.Fn sdp_register_service
function
is used to register service with the local SDP server.
The
.Fa xss
parameter should point to a valid SDP session object obtained from
.Fn sdp_open_local .
The
.Fa uuid
parameter is a SDP Service Class ID for the service to be registered.
The
.Fa bdaddr
parameter should point to a valid BD_ADDR.
The service will be only advertised if request was received by the local device
with
.Fa bdaddr .
If
.Fa bdaddr
is set to
.Dv NG_HCI_BDADDR_ANY
then the service will be advertised to any remote devices that queries for it.
The
.Fa data
and
.Fa datalen
parameters specify data and size of the data for the service.
Upon successful return
.Fn sdp_register_service
will populate
.Fa handle
with the SDP record handle.
This parameter is optional and can be set to
.Dv NULL .
.Pp
The
.Fn sdp_unregister_service
function
is used to unregister service with the local SDP server.
The
.Fa xss
parameter should point to a valid SDP session object obtained from
.Fn sdp_open_local .
The
.Fa handle
parameter should contain a valid SDP record handle of the service to be
unregistered.
.Pp
The
.Fn sdp_change_service
function is used to change data associated with the existing service on
the local SDP server.
The
.Fa xss
parameter should point to a valid SDP session object obtained from
.Fn sdp_open_local .
The
.Fa handle
parameter should contain a valid SDP record handle of the service to be changed.
The
.Fa data
and
.Fa datalen
parameters specify data and size of the data for the service.
.Sh CAVEAT
When registering services with the local SDP server the application must
keep the SDP session open.
If SDP session is closed then the local SDP server will remove all services
that were registered over the session.
The application is allowed to change or unregister service if it was registered
over the same session.
.Sh EXAMPLES
The following example shows how to get
.Dv SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST
attribute for the
.Dv SDP_SERVICE_CLASS_SERIAL_PORT
service from the remote device.
.Bd -literal -offset indent
bdaddr_t       remote;
uint8_t        buffer[1024];
void          *ss    = NULL;
uint16_t       serv  = SDP_SERVICE_CLASS_SERIAL_PORT;
uint32_t       attr  = SDP_ATTR_RANGE(
                            SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST,
                            SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST);
sdp_attr_t     proto = { SDP_ATTR_INVALID,0,sizeof(buffer),buffer };

/* Obtain/set remote BDADDR here */

if ((ss = sdp_open(NG_HCI_BDADDR_ANY, remote)) == NULL)
        /* exit ENOMEM */
if (sdp_error(ss) != 0)
        /* exit sdp_error(ss) */

if (sdp_search(ss, 1, &serv, 1, &attr, 1, &proto) != 0)
        /* exit sdp_error(ss) */

if (proto.flags != SDP_ATTR_OK)
        /* exit see proto.flags for details */

/* If we got here then we have attribute value in proto.value */
.Ed
.Sh DIAGNOSTICS
Both
.Fn sdp_open
and
.Fn sdp_open_local
will return
.Dv NULL
if memory allocation for the new SDP session object fails.
If the new SDP object was created then caller is still expected to call
.Fn sdp_error
to check if there was connection error.
.Pp
The
.Fn sdp_get_lcaddr ,
.Fn sdp_search ,
.Fn sdp_register_service ,
.Fn sdp_unregister_service ,
and
.Fn sdp_change_service
functions return non-zero value on error.
The caller is expected to call
.Fn sdp_error
to find out more about error.
.Sh SEE ALSO
.Xr bluetooth 3 ,
.Xr strerror 3 ,
.Xr sdpcontrol 8 ,
.Xr sdpd 8
.Sh AUTHORS
.An Maksim Yevmenkin Aq Mt m_evmenkin@yahoo.com
.Sh BUGS
Most likely.
Please report bugs if found.