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Manual Page Search Parameters

SDP(3) Library Functions Manual SDP(3)

SDP_GET8, SDP_GET16, SDP_GET32, SDP_GET64, SDP_GET128, SDP_GET_UUID128, SDP_PUT8, SDP_PUT16, SDP_PUT32, SDP_PUT64, SDP_PUT128, SDP_PUT_UUID128, sdp_open, sdp_open_local, sdp_close, sdp_error, sdp_search, sdp_attr2desc, sdp_uuid2descBluetooth SDP routines

library “libsdp”

#include <bluetooth.h>
#include <sdp.h>

SDP_GET8(b, cp);

SDP_GET16(s, cp);

SDP_GET32(l, cp);

SDP_GET64(l, cp);

SDP_GET128(l, cp);

SDP_GET_UUID128(l, cp);

SDP_PUT8(b, cp);

SDP_PUT16(s, cp);

SDP_PUT32(l, cp);

SDP_PUT64(l, cp);

SDP_PUT128(l, cp);

SDP_PUT_UUID128(l, cp);

void *
sdp_open(bdaddr_t const *l, bdaddr_t const *r);

void *
sdp_open_local(char const *control);

int32_t
sdp_close(void *xs);

int32_t
sdp_error(void *xs);

int32_t
sdp_search(void *xs, uint32_t plen, uint16_t const *pp, uint32_t alen, uint32_t const *ap, uint32_t vlen, sdp_attr_t *vp);

char const *
sdp_attr2desc(uint16_t attr);

char const *
sdp_uuid2desc(uint16_t uuid);

int32_t
sdp_register_service(void *xss, uint16_t uuid, bdaddr_t *bdaddr, uint8_t *data, uint32_t datalen, uint32_t *handle);

int32_t
sdp_unregister_service(void *xss, uint32_t handle);

int32_t
sdp_change_service(void *xss, uint32_t handle, uint8_t *data, uint32_t datalen);

The (), (), (), () and () macros are used to get byte, short, long, long long and 128-bit integer from the buffer pointed by cp pointer. The pointer is automatically advanced.

The (), (), (), () and () macros are used to put byte, short, long, long long and 128-bit integer into the buffer pointed by cp pointer. The pointer is automatically advanced.

() and () macros are used to get and put 128-bit UUID into the buffer pointed by cp pointer. The pointer is automatically advanced.

The () and () functions each return a pointer to an opaque object describing SDP session. The l argument passed to sdp_open() function should point to a source BD_ADDR. If source BD_ADDR is NULL then source address BDADDR_ANY is used. The r argument passed to sdp_open() function should point to a non-NULL remote BD_ADDR. Remote BD_ADDR cannot be BDADDR_ANY. The 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 NULL then default /var/run/sdp path will be used.

The () function terminates active SDP session and deletes SDP session object. The xs parameter should point to a valid SDP session object created with sdp_open() or sdp_open_local().

The () function returns last error that is stored inside SDP session object. The xs parameter should point to a valid SDP session object created with sdp_open() or sdp_open_local(). The error value returned can be converted to a human readable message by calling strerror(3) function.

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;

The caller of the () function is expected to prepare the array of sdp_attr structures and for each element of the array both vlen and value must be set. The sdp_search() function will fill each sdp_attr_t structure with attribute and value, i.e., it will set flags, attr and vlen fields. The actual value of the attribute will be copied into 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 secord record etc.

The () and () functions each take a numeric attribute ID/UUID value and convert it to a human readable description.

The () function is used to register service with the local SDP server. The xss parameter should point to a valid SDP session object obtained from (). The uuid parameter is a SDP Service Class ID for the service to be registered. The bdaddr parameter should point to a valid BD_ADDR. The service will be only advertised if request was received by the local device with bdaddr. If bdaddr is set to BDADDR_ANY then the service will be advertised to any remote devices that queries for it. The data and datalen parameters specify data and size of the data for the service. Upon successful return sdp_register_service() will populate handle with the SDP record handle. This parameter is optional and can be set to NULL.

The () function is used to unregister service with the local SDP server. The xss parameter should point to a valid SDP session object obtained from (). The handle parameter should contain a valid SDP record handle of the service to be unregistered.

The () function is used to change data associated with the existing service on the local SDP server. The xss parameter should point to a valid SDP session object obtained from (). The handle parameter should contain a valid SDP record handle of the service to be changed. The data and datalen parameters specify data and size of the data for the service.

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.

The following example shows how to get SDP_ATTR_PROTOCOL_DESCRIPTOR_LIST attribute for the SDP_SERVICE_CLASS_SERIAL_PORT service from the remote device.

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(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 */

Both sdp_open() and sdp_open_local() will return 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 sdp_error() to check if there was connection error.

The sdp_search(), sdp_register_service(), sdp_unregister_service() and sdp_change_service() functions return non-zero value on error. The caller is expected to call sdp_error() to find out more about error.

sdpquery(1), strerror(3), bluetooth(4), sdpd(8)

libsdp first appeared in FreeBSD, was ported to NetBSD 4.0 by Iain Hibbert and imported into DragonFly 1.11.

Maksim Yevmenkin <m_evmenkin@yahoo.com>

Most likely. Please report bugs if found.

April 6, 2018 DragonFly-5.6.1