/* WinPCAP function. */
void pcap_callback( u_char *user, const struct pcap_pkthdr *pkt_header, const u_char *pkt_data )
{
(void)user;
/* THIS IS CALLED FROM A WINDOWS THREAD - DO NOT ATTEMPT ANY FREERTOS CALLS
OR TO PRINT OUT MESSAGES HERE. */
/* Pass data to the FreeRTOS simulator on a thread safe circular buffer. */
if( ( pkt_header->caplen <= ( ipconfigNETWORK_MTU + ipSIZE_OF_ETH_HEADER ) ) &&
( uxStreamBufferGetSpace( xRecvBuffer ) >= ( ( ( size_t ) pkt_header->caplen ) + sizeof( *pkt_header ) ) ) )
{
uxStreamBufferAdd( xRecvBuffer, 0, ( const uint8_t* ) pkt_header, sizeof( *pkt_header ) );
uxStreamBufferAdd( xRecvBuffer, 0, ( const uint8_t* ) pkt_data, ( size_t ) pkt_header->caplen );
}
}
BaseType_t xNetworkInterfaceOutput( NetworkBufferDescriptor_t * const pxNetworkBuffer, BaseType_t bReleaseAfterSend )
{
size_t xSpace;
iptraceNETWORK_INTERFACE_TRANSMIT();
configASSERT( xIsCallingFromIPTask() == pdTRUE );
/* Both the length of the data being sent and the actual data being sent
are placed in the thread safe buffer used to pass data between the FreeRTOS
tasks and the Win32 thread that sends data via the WinPCAP library. Drop
the packet if there is insufficient space in the buffer to hold both. */
xSpace = uxStreamBufferGetSpace( xSendBuffer );
if( ( pxNetworkBuffer->xDataLength <= ( ipconfigNETWORK_MTU + ipSIZE_OF_ETH_HEADER ) ) &&
( xSpace >= ( pxNetworkBuffer->xDataLength + sizeof( pxNetworkBuffer->xDataLength ) ) ) )
{
/* First write in the length of the data, then write in the data
itself. */
uxStreamBufferAdd( xSendBuffer, 0, ( const uint8_t * ) &( pxNetworkBuffer->xDataLength ), sizeof( pxNetworkBuffer->xDataLength ) );
uxStreamBufferAdd( xSendBuffer, 0, ( const uint8_t * ) pxNetworkBuffer->pucEthernetBuffer, pxNetworkBuffer->xDataLength );
}
else
{
FreeRTOS_debug_printf( ( "xNetworkInterfaceOutput: send buffers full to store %lu\n", pxNetworkBuffer->xDataLength ) );
}
/* Kick the Tx task in either case in case it doesn't know the buffer is
full. */
SetEvent( pvSendEvent );
/* The buffer has been sent so can be released. */
if( bReleaseAfterSend != pdFALSE )
{
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
return pdPASS;
}
/*
* uxStreamBufferAdd( )
* Adds data to a stream buffer. If uxOffset > 0, data will be written at
* an offset from uxHead while uxHead will not be moved yet. This possibility
* will be used when TCP data is received while earlier data is still missing.
* If 'pucData' equals NULL, the function is called to advance 'uxHead' only.
*/
size_t uxStreamBufferAdd( StreamBuffer_t *pxBuffer, size_t uxOffset, const uint8_t *pucData, size_t uxCount )
{
size_t uxSpace, uxNextHead, uxFirst;
uxSpace = uxStreamBufferGetSpace( pxBuffer );
/* If uxOffset > 0, items can be placed in front of uxHead */
if( uxSpace > uxOffset )
{
uxSpace -= uxOffset;
}
else
{
uxSpace = 0u;
}
/* The number of bytes that can be written is the minimum of the number of
bytes requested and the number available. */
uxCount = FreeRTOS_min_uint32( uxSpace, uxCount );
if( uxCount != 0u )
{
uxNextHead = pxBuffer->uxHead;
if( uxOffset != 0u )
{
/* ( uxOffset > 0 ) means: write in front if the uxHead marker */
uxNextHead += uxOffset;
if( uxNextHead >= pxBuffer->LENGTH )
{
uxNextHead -= pxBuffer->LENGTH;
}
}
if( pucData != NULL )
{
/* Calculate the number of bytes that can be added in the first
write - which may be less than the total number of bytes that need
to be added if the buffer will wrap back to the beginning. */
uxFirst = FreeRTOS_min_uint32( pxBuffer->LENGTH - uxNextHead, uxCount );
/* Write as many bytes as can be written in the first write. */
memcpy( ( void* ) ( pxBuffer->ucArray + uxNextHead ), pucData, uxFirst );
/* If the number of bytes written was less than the number that
could be written in the first write... */
if( uxCount > uxFirst )
{
/* ...then write the remaining bytes to the start of the
buffer. */
memcpy( ( void * )pxBuffer->ucArray, pucData + uxFirst, uxCount - uxFirst );
}
}
if( uxOffset == 0u )
{
/* ( uxOffset == 0 ) means: write at uxHead position */
uxNextHead += uxCount;
if( uxNextHead >= pxBuffer->LENGTH )
{
uxNextHead -= pxBuffer->LENGTH;
}
pxBuffer->uxHead = uxNextHead;
}
if( xStreamBufferLessThenEqual( pxBuffer, pxBuffer->uxFront, uxNextHead ) != pdFALSE )
{
/* Advance the front pointer */
pxBuffer->uxFront = uxNextHead;
}
}
return uxCount;
}
