May 27, 2005 SDP 3

### NAME

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_uuid2desc - Bluetooth SDP routines

### LIBRARY

Service Discovery Protocol Library (libsdp, -lsdp)

### SYNOPSIS

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 * const` sdp_attr2desc(```uint16_t attr`)
```char const * const` sdp_uuid2desc(```uint16_t uuid`)
```int32_t` sdp_register_service(`` ```void *xss` `uint16_t uuid` `bdaddr_t const *bdaddr` `uint8_t const *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 const *data` `uint32_t datalen` )

### DESCRIPTION

The SDP_GET8(``), SDP_GET16(``), SDP_GET32(``), SDP_GET64(``) and SDP_GET128(``) 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 SDP_PUT8(``), SDP_PUT16(``), SDP_PUT32(``), SDP_PUT64(``) and SDP_PUT128(``) 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.

SDP_GET_UUID128(``) and SDP_PUT_UUID128(``) macros are used to get and put 128-bit UUID into the buffer pointed by ```cp` pointer. The pointer is automatically advanced.

The sdp_open(``) and sdp_open_local(``) 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 sdp_close(``) 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 sdp_error(``) 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.

The sdp_search(``) function is used to perform SDP Service Search Attribute Request. The ```xs` parameter should point to a valid SDP session object created with sdp_open(``) or sdp_open_local(``). The ```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 ```plen` parameter is the length of the Service Search pattern. The ```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 ```alen` parameter is the length of the Attribute ID Ranges List. The SDP_ATTR_RANGE(```lo``, hi`) macro can be used to prepare Attribute ID Range. The ```vp` parameter should be an array of structures. Each structure describes single SDP attribute and defined as follows:

  `

      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 sdp_search(``) function is expected to prepare the array of structures and for each element of the array both vlen and value must be set. The sdp_search(``) function will fill each 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 sdp_attr2desc(``) and sdp_uuid2desc(``) functions each take a numeric attribute ID/UUID value and convert it to a human readable description.

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

The sdp_change_service(``) 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 sdp_open_local(``). 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.

### 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.

### EXAMPLES

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 */

  `

### DIAGNOSTICS

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.

### SEE ALSO

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

### AUTHORS

Maksim Yevmenkin <m_evmenkin@yahoo.com>

### BUGS

Most likely. Please report bugs if found.

### HISTORY

libsdp first appeared in FreeBSD and was ported to NetBSD4.0 by Iain Hibbert
.