/** Retrieves the size of a Data Element container from the current input buffer, and advances the input buffer
* pointer to the start of the Data Element's contents.
*
* \param[in, out] DataElementHeader Pointer to the start of a Data Element header
* \param[out] ElementHeaderSize Size in bytes of the header that was skipped
*
* \return Size in bytes of the Data Element container's contents, minus the header
*/
static uint32_t SDP_GetDataElementSize(const void** const DataElementHeader,
uint8_t* const ElementHeaderSize)
{
/* Fetch the size of the Data Element structure from the header, increment the current buffer pos */
uint8_t SizeIndex = (SDP_ReadData8(DataElementHeader) & 0x07);
uint32_t ElementValueSize;
/* Convert the Data Element size index into a size in bytes */
switch (SizeIndex)
{
case SDP_DATASIZE_Variable8Bit:
*ElementHeaderSize = (1 + sizeof(uint8_t));
ElementValueSize = SDP_ReadData8(DataElementHeader);
break;
case SDP_DATASIZE_Variable16Bit:
*ElementHeaderSize = (1 + sizeof(uint16_t));
ElementValueSize = SDP_ReadData16(DataElementHeader);
break;
case SDP_DATASIZE_Variable32Bit:
*ElementHeaderSize = (1 + sizeof(uint32_t));
ElementValueSize = SDP_ReadData32(DataElementHeader);
break;
default:
*ElementHeaderSize = 1;
ElementValueSize = (1 << SizeIndex);
break;
}
return ElementValueSize;
}
static void SDP_ServiceAttribute(BT_StackConfig_t* const StackState,
BT_L2CAP_Channel_t* const Channel,
BT_SDP_PDUHeader_t* const SDPHeader)
{
const void* CurrParameterPos = SDPHeader->Parameters;
/* Read service record handle */
uint32_t RecordHandle = SDP_ReadData32(&CurrParameterPos);
/* Read maximum attribute size byte count for the response */
uint16_t MaximumAttributeSize = SDP_ReadData16(&CurrParameterPos);
/* Read search Attribute list sequence header and obtain its data size and a pointer to start of the data */
uint16_t AttributeList[8][2];
uint8_t TotalAttributes = SDP_GetAttributeList(AttributeList, &CurrParameterPos);
/* Read continuation state value from the client */
uint8_t ContinuationState = SDP_ReadData8(&CurrParameterPos);
struct
{
BT_SDP_PDUHeader_t SDPHeader;
uint16_t AttributeListByteCount;
uint8_t ResponseData[200];
} ATTR_PACKED ResponsePacket;
/* Create a pointer to the buffer to indicate the current location for response data to be added */
void* CurrResponsePos = ResponsePacket.ResponseData;
/* Clamp the maximum attribute size to the size of the allocated buffer */
if (MaximumAttributeSize > sizeof(ResponsePacket.ResponseData))
MaximumAttributeSize = sizeof(ResponsePacket.ResponseData);
/* Search through all registered services, looking for UUID matches */
SDP_ServiceEntry_t* CurrentService = RegisteredServices;
while (CurrentService != NULL)
{
/* Retrieve a PROGMEM pointer to the value of the Service Record Handle */
const void* ServiceRecord = SDP_GetAttributeValue(CurrentService, SDP_ATTRIBUTE_ID_SERVICERECORDHANDLE);
/* Check if matching service record found in the table */
if (ServiceRecord)
{
/* Get the size of the header for the Service Record Handle */
uint8_t AttrHeaderSize;
SDP_GetLocalAttributeContainerSize(ServiceRecord, &AttrHeaderSize);
/* Retrieve the endian-swapped service handle of the current service being examined */
uint32_t CurrServiceHandle = be32_to_cpu(pgm_read_dword(ServiceRecord + AttrHeaderSize));
/* Check if the current service in the service table has the requested service handle */
if (RecordHandle == CurrServiceHandle)
{
/* Add the listed attributes for the found UUID to the response */
SDP_AddListedAttributesToResponse(CurrentService, AttributeList, TotalAttributes, &CurrResponsePos);
/* Requested service found, abort the search through the service table */
break;
}
}
/* Select next registered service in the service table list */
CurrentService = CurrentService->NextService;
}
/* Continuation state - always zero */
SDP_WriteData8(&CurrResponsePos, 0);
/* Set the total response list size to the size of the outer container plus its header size and continuation state */
ResponsePacket.AttributeListByteCount = cpu_to_be16((uintptr_t)CurrResponsePos - (uintptr_t)ResponsePacket.ResponseData - sizeof(uint8_t));
/* Fill in the response packet's header */
ResponsePacket.SDPHeader.PDU = SDP_PDU_SERVICEATTRIBUTERESPONSE;
ResponsePacket.SDPHeader.TransactionID = SDPHeader->TransactionID;
ResponsePacket.SDPHeader.ParameterLength = cpu_to_be16(sizeof(ResponsePacket.AttributeListByteCount) + be16_to_cpu(ResponsePacket.AttributeListByteCount) + sizeof(uint8_t));
/* Send the completed response packet to the sender */
SDP_SendFrame(StackState, Channel, (sizeof(ResponsePacket.SDPHeader) + be16_to_cpu(ResponsePacket.SDPHeader.ParameterLength)), &ResponsePacket);
}
/** Internal processing routine for SDP Service Attribute Requests.
*
* \param[in] SDPHeader Pointer to the start of the issued SDP request
* \param[in] Channel Pointer to the Bluetooth channel structure the request was issued to
*/
static void SDP_ProcessServiceAttribute(const SDP_PDUHeader_t* const SDPHeader,
Bluetooth_Channel_t* const Channel)
{
const void* CurrentParameter = ((const void*)SDPHeader + sizeof(SDP_PDUHeader_t));
BT_SDP_DEBUG(1, "<< Service Attribute");
/* Retrieve the service handle whose attributes are to be examined */
uint32_t ServiceHandle = SDP_ReadData32(&CurrentParameter);
BT_SDP_DEBUG(2, "-- Service Handle: 0x%08lX", ServiceHandle);
/* Retrieve the maximum Attribute response size from the request */
uint16_t MaxAttributeSize = SDP_ReadData16(&CurrentParameter);
BT_SDP_DEBUG(2, "-- Max Return Attribute Bytes: 0x%04X", MaxAttributeSize);
/* Retrieve the list of Attributes from the request */
uint16_t AttributeList[8][2];
uint8_t TotalAttributes = SDP_GetAttributeList(AttributeList, &CurrentParameter);
BT_SDP_DEBUG(2, "-- Total Attributes: %d", TotalAttributes);
struct
{
SDP_PDUHeader_t SDPHeader;
uint16_t AttributeListByteCount;
uint8_t ResponseData[100];
} ResponsePacket;
/* Create a pointer to the buffer to indicate the current location for response data to be added */
void* CurrResponsePos = ResponsePacket.ResponseData;
/* Clamp the maximum attribute size to the size of the allocated buffer */
if (MaxAttributeSize > sizeof(ResponsePacket.ResponseData))
MaxAttributeSize = sizeof(ResponsePacket.ResponseData);
uint16_t TotalResponseSize = 0;
/* Search through the global UUID list an item at a time */
for (uint8_t CurrTableItem = 0; CurrTableItem < (sizeof(SDP_Services_Table) / sizeof(void*)); CurrTableItem++)
{
/* Read in a pointer to the current UUID table entry's Attribute table */
ServiceAttributeTable_t* CurrAttributeTable = pgm_read_ptr(&SDP_Services_Table[CurrTableItem]);
/* Retrieve a PROGMEM pointer to the value of the Service Record Handle */
const void* ServiceRecord = SDP_GetAttributeValue(CurrAttributeTable, SDP_ATTRIBUTE_ID_SERVICERECORDHANDLE);
/* Get the size of the header for the Service Record Handle */
uint8_t AttrHeaderSize;
SDP_GetLocalAttributeContainerSize(ServiceRecord, &AttrHeaderSize);
/* Retrieve the endian-swapped service handle of the current service being examined */
uint32_t CurrServiceHandle = SwapEndian_32(pgm_read_dword(ServiceRecord + AttrHeaderSize));
/* Check if the current service in the service table has the requested service handle */
if (ServiceHandle == CurrServiceHandle)
{
/* Add the listed attributes for the found UUID to the response */
TotalResponseSize = SDP_AddListedAttributesToResponse(CurrAttributeTable, AttributeList, TotalAttributes,
&CurrResponsePos);
/* Requested service found, abort the search through the service table */
break;
}
}
/* Continuation state - always zero */
SDP_WriteData8(&CurrResponsePos, 0);
/* Set the total response list size to the size of the outer container plus its header size and continuation state */
ResponsePacket.AttributeListByteCount = SwapEndian_16(TotalResponseSize);
/* Calculate the total parameter length that is to be sent, including the fixed return parameters, the created attribute
value list and the SDP continuation state */
uint16_t ParamLength = (sizeof(ResponsePacket.AttributeListByteCount) + TotalResponseSize + sizeof(uint8_t));
/* Fill in the response packet's header */
ResponsePacket.SDPHeader.PDU = SDP_PDU_SERVICEATTRIBUTERESPONSE;
ResponsePacket.SDPHeader.TransactionID = SDPHeader->TransactionID;
ResponsePacket.SDPHeader.ParameterLength = SwapEndian_16(ParamLength);
BT_SDP_DEBUG(1, ">> Service Attribute Response");
BT_SDP_DEBUG(2, "-- Param Len 0x%04X", ParamLength);
/* Send the completed response packet to the sender */
Bluetooth_SendPacket(&ResponsePacket, (sizeof(ResponsePacket.SDPHeader) + ParamLength), Channel);
}