text: /*
   * FreeRTOS Kernel V10.3.0
   * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy of
   * this software and associated documentation files (the "Software"), to deal in
   * the Software without restriction, including without limitation the rights to
   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
   * the Software, and to permit persons to whom the Software is furnished to do so,
   * subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
   * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
   * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   * http://www.FreeRTOS.org
   * http://aws.amazon.com/freertos
   *
   * 1 tab == 4 spaces!
   */
  
  /* WinPCap includes. */
  #include "pcap.h"
  #include "remote-ext.h"
  
  /* uIP includes. */
  #include "net/uip.h"
  #include "net/uip_arp.h"
  #include "net/clock-arch.h"
  
  /* FreeRTOS includes. */
  #include "FreeRTOS.h"
  #include "task.h"
  #include "queue.h"
  
  /*
   * Query the computer the simulation is being executed on to find the network
   * interfaces it has installed.
   */
  static pcap_if_t * prvPrintAvailableNetworkInterfaces( void );
  
  /*
   * Open the network interface.  The number of the interface to be opened is set
   * by the configNETWORK_INTERFACE_TO_USE constant in FreeRTOSConfig.h.
   */
  static void prvOpenSelectedNetworkInterface( pcap_if_t *pxAllNetworkInterfaces );
  
  /*
   * Configure the capture filter to allow blocking reads, and to filter out
   * packets that are not of interest to this demo.
   */
  static void prvConfigureCaptureBehaviour( void );
  
  pcap_t *pxOpenedInterfaceHandle = NULL;
  LARGE_INTEGER freq, sys_start_time;
  
  #define archNUM_BUFFERS	5
  #define archNUM_BUFFER_POINTERS ( archNUM_BUFFERS - 1 )
  
  static void prvInterruptSimulator( void *pvParameters );
  
  static unsigned char ucEthernetBuffer[ archNUM_BUFFERS ][ UIP_CONF_BUFFER_SIZE ];
  static unsigned char *pucEthernetBufferPointers[ archNUM_BUFFER_POINTERS ];
  
  static long lLengthOfDataInBuffer[ archNUM_BUFFER_POINTERS ] = { 0 };
  static unsigned char ucNextBufferToFill = 0U, ucNextBufferToProcess = 0U;
  
  unsigned char *uip_buf = NULL;
  char cErrorBuffer[PCAP_ERRBUF_SIZE];
  
  void vNetifTx( void )
  {
  	pcap_sendpacket( pxOpenedInterfaceHandle, uip_buf, uip_len );
  	pcap_sendpacket( pxOpenedInterfaceHandle, uip_buf, uip_len );
  }
  /*-----------------------------------------------------------*/
  
  unsigned portBASE_TYPE uxNetifRx( void )
  {
  unsigned portBASE_TYPE xDataLen;
  unsigned char *pucTemp;
  
  	/* Check there is really data available. */
  	xDataLen = lLengthOfDataInBuffer[ ucNextBufferToProcess ];
  	if( xDataLen != 0L )
  	{
  
  		/* The buffer pointed to by uip_buf is going to change.  Remember which
  		buffer uip_buf is currently pointing to. */
  		pucTemp = uip_buf;
  
  		/* Point uip_buf at the next buffer that contains data. */
  		uip_buf = pucEthernetBufferPointers[ ucNextBufferToProcess ];
  
  		/* The buffer pointed to by 
  		pucEthernetBufferPointeres[ ucNextBufferToProcess ] is now in use by
  		uip_buf, but the buffer uip_buf was pointing to on entry to this
  		function is free.  Set 
  		pucEthernetBufferPointeres[ ucNextBufferToProcess ] to the free 
  		buffer. */
  		pucEthernetBufferPointers[ ucNextBufferToProcess ] = pucTemp;
  		lLengthOfDataInBuffer[ ucNextBufferToProcess ] = 0L;
  
  		ucNextBufferToProcess++;
  		if( ucNextBufferToProcess >= archNUM_BUFFER_POINTERS )
  		{
  			ucNextBufferToProcess = 0L;
  		}
  	}
  
  	return xDataLen;
  }
  /*-----------------------------------------------------------*/
  
  portBASE_TYPE xNetifInit( void )
  {
  portBASE_TYPE x;
  pcap_if_t *pxAllNetworkInterfaces;
  
  	/* Allocate a free buffer to each buffer pointer. */
  	for( x = 0; x < sizeof( pucEthernetBufferPointers ) / sizeof( unsigned char * ); x++ )
  	{
  		pucEthernetBufferPointers[ x ] = &( ucEthernetBuffer[ x ][ 0 ] );
  	}
  
  	/* Start with uip_buf pointing to a buffer that is not referenced from the
  	pucEthernetBufferPointers[] array. */
  	uip_buf = &( ucEthernetBuffer[ archNUM_BUFFERS - 1 ][ 0 ] );
  
  	/* Query the computer the simulation is being executed on to find the 
  	network interfaces it has installed. */
  	pxAllNetworkInterfaces = prvPrintAvailableNetworkInterfaces();
  	
  	/* Open the network interface.  The number of the interface to be opened is 
  	set by the configNETWORK_INTERFACE_TO_USE constant in FreeRTOSConfig.h.
  	Calling this function will set the pxOpenedInterfaceHandle variable.  If,
  	after calling this function, pxOpenedInterfaceHandle is equal to NULL, then
  	the interface could not be opened. */
  	if( pxAllNetworkInterfaces != NULL )
  	{
  		prvOpenSelectedNetworkInterface( pxAllNetworkInterfaces );
  	}
  	
  
  	return x;
  }
  /*-----------------------------------------------------------*/
  
  static pcap_if_t * prvPrintAvailableNetworkInterfaces( void )
  {    
  pcap_if_t * pxAllNetworkInterfaces = NULL, *xInterface;
  long lInterfaceNumber = 1;
  
      if( pcap_findalldevs_ex( PCAP_SRC_IF_STRING, NULL, &pxAllNetworkInterfaces, cErrorBuffer ) == -1 )
      {
          printf( "\r\nCould not obtain a list of network interfaces\r\n%s\r\n", cErrorBuffer );
          pxAllNetworkInterfaces = NULL;
      }
  
  	if( pxAllNetworkInterfaces != NULL )
  	{
  		/* Print out the list of network interfaces.  The first in the list
  		is interface '1', not interface '0'. */
  		for( xInterface = pxAllNetworkInterfaces; xInterface != NULL; xInterface = xInterface->next )
  		{
  			printf( "%d. %s", lInterfaceNumber, xInterface->name );
  			
  			if( xInterface->description != NULL )
  			{
  				printf( " (%s)\r\n", xInterface->description );
  			}
  			else
  			{
  				printf( " (No description available)\r\n") ;
  			}
  			
  			lInterfaceNumber++;
  		}
  	}
  
      if( lInterfaceNumber == 1 )
      {
  		/* The interface number was never incremented, so the above for() loop
  		did not execute meaning no interfaces were found. */
          printf( " \r\nNo network interfaces were found.\r\n" );
          pxAllNetworkInterfaces = NULL;
      }
  
  	printf( "\r\nThe interface that will be opened is set by configNETWORK_INTERFACE_TO_USE which should be defined in FreeRTOSConfig.h\r\n" );
  	printf( "Attempting to open interface number %d.\r\n", configNETWORK_INTERFACE_TO_USE );
  	
      if( ( configNETWORK_INTERFACE_TO_USE < 1L ) || ( configNETWORK_INTERFACE_TO_USE > lInterfaceNumber ) )
      {
          printf("\r\nconfigNETWORK_INTERFACE_TO_USE is not in the valid range.\r\n" );
  		
  		if( pxAllNetworkInterfaces != NULL )
  		{
  			/* Free the device list, as no devices are going to be opened. */
  			pcap_freealldevs( pxAllNetworkInterfaces );
  			pxAllNetworkInterfaces = NULL;
  		}
      }
  
  	return pxAllNetworkInterfaces;
  }
  /*-----------------------------------------------------------*/
  
  static void prvOpenSelectedNetworkInterface( pcap_if_t *pxAllNetworkInterfaces )
  {
  pcap_if_t *xInterface;
  long x;
  
      /* Walk the list of devices until the selected device is located. */
  	xInterface = pxAllNetworkInterfaces;
      for( x = 0L; x < ( configNETWORK_INTERFACE_TO_USE - 1L ); x++ )
  	{
  		xInterface = xInterface->next;
  	}
  
      /* Open the selected interface. */
  	pxOpenedInterfaceHandle = pcap_open(	xInterface->name,          	/* The name of the selected interface. */
  											UIP_CONF_BUFFER_SIZE, 		/* The size of the packet to capture. */
  											PCAP_OPENFLAG_PROMISCUOUS,	/* Open in promiscious mode as the MAC and 
  																		IP address is going to be "simulated", and 
  																		not be the real MAC and IP address.  This allows
  																		trafic to the simulated IP address to be routed
  																		to uIP, and trafic to the real IP address to be
  																		routed to the Windows TCP/IP stack. */
  											0xfffffffL,             	/* The read time out.  This is going to block
  																		until data is available. */
  											NULL,             			/* No authentication is required as this is
  																		not a remote capture session. */
  											cErrorBuffer            
  									   );
  									   
      if ( pxOpenedInterfaceHandle == NULL )
      {
          printf( "\r\n%s is not supported by WinPcap and cannot be opened\r\n", xInterface->name );
      }
  	else
  	{
  		/* Configure the capture filter to allow blocking reads, and to filter 
  		out packets that are not of interest to this demo. */
  		prvConfigureCaptureBehaviour();
  	}
  
  	/* The device list is no longer required. */
  	pcap_freealldevs( pxAllNetworkInterfaces );
  }
  /*-----------------------------------------------------------*/
  
  static void prvConfigureCaptureBehaviour( void )
  {
  struct bpf_program xFilterCode;
  const long lMinBytesToCopy = 10L, lBlocking = 0L;
  unsigned long ulNetMask;
  
  	/* Unblock a read as soon as anything is received. */
  	pcap_setmintocopy( pxOpenedInterfaceHandle, lMinBytesToCopy );
  
  	/* Allow blocking. */
  	pcap_setnonblock( pxOpenedInterfaceHandle, lBlocking, cErrorBuffer );
  
  	/* Set up a filter so only the packets of interest are passed to the uIP
  	stack.  cErrorBuffer is used for convenience to create the string.  Don't
  	confuse this with an error message. */
  	sprintf( cErrorBuffer, "broadcast or multicast or host %d.%d.%d.%d", configIP_ADDR0, configIP_ADDR1, configIP_ADDR2, configIP_ADDR3 );
  
  	ulNetMask = ( configNET_MASK3 << 24UL ) | ( configNET_MASK2 << 16UL ) | ( configNET_MASK1 << 8L ) | configNET_MASK0;
  
  	if( pcap_compile(pxOpenedInterfaceHandle, &xFilterCode, cErrorBuffer, 1, ulNetMask ) < 0 )
      {
          printf("\r\nThe packet filter string is invalid\r\n" );
      }
  	else
  	{    
  		if( pcap_setfilter( pxOpenedInterfaceHandle, &xFilterCode ) < 0 )
  		{
  			printf( "\r\nAn error occurred setting the packet filter.\r\n" );
  		}
  	}
  
  	/* Create a task that simulates an interrupt in a real system.  This will
  	block waiting for packets, then send a message to the uIP task when data
  	is available. */
  	xTaskCreate( prvInterruptSimulator, "MAC_ISR", configMINIMAL_STACK_SIZE, NULL, ( configuIP_TASK_PRIORITY - 1 ), NULL );
  }
  /*-----------------------------------------------------------*/
  
  static void prvInterruptSimulator( void *pvParameters )
  {
  static struct pcap_pkthdr *pxHeader;
  const unsigned char *pucPacketData;
  extern QueueHandle_t xEMACEventQueue;
  const unsigned long ulRxEvent = uipETHERNET_RX_EVENT;
  long lResult;
  
  	/* Just to kill the compiler warning. */
  	( void ) pvParameters;
  
  	for( ;; )
  	{
  		/* Get the next packet. */
  		lResult = pcap_next_ex( pxOpenedInterfaceHandle, &pxHeader, &pucPacketData );
  		if( lResult )
  		{
  			/* Is the next buffer into which data should be placed free? */
  			if( lLengthOfDataInBuffer[ ucNextBufferToFill ] == 0L )
  			{
  				/* Copy the data from the captured packet into the buffer. */
  				memcpy( pucEthernetBufferPointers[ ucNextBufferToFill ], pucPacketData, pxHeader->len );
  
  				/* Note the amount of data that was copied. */
  				lLengthOfDataInBuffer[ ucNextBufferToFill ] = pxHeader->len;
  
  				/* Move onto the next buffer, wrapping around if necessary. */
  				ucNextBufferToFill++;
  				if( ucNextBufferToFill >= archNUM_BUFFER_POINTERS )
  				{
  					ucNextBufferToFill = 0U;
  				}
  
  				/* Data was received and stored.  Send a message to the uIP task
  				to let it know. */
  				xQueueSendToBack( xEMACEventQueue, &ulRxEvent, portMAX_DELAY );
  			}
  		}
  	}
  }
  
  