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2022-01-04 12:22:53 +02:00

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4.3 KiB
C

/**HEADER********************************************************************
*
* Copyright (c) 2008 Freescale Semiconductor;
* All Rights Reserved
*
* Copyright (c) 2004-2008 Embedded Access Inc.;
* All Rights Reserved
*
* Copyright (c) 1989-2008 ARC International;
* All Rights Reserved
*
***************************************************************************
*
* THIS SOFTWARE IS PROVIDED BY FREESCALE "AS IS" AND ANY EXPRESSED OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL FREESCALE OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*
**************************************************************************
*
* $FileName: checksum.c$
* $Version : 3.8.7.0$
* $Date : Jun-14-2012$
*
* Comments:
*
* This file contains the implementation for a one's
* complement checksum.
*
*END************************************************************************/
#include <rtcs.h>
#include "rtcs_prv.h"
#include "tcpip.h"
#include "ip_prv.h"
/*FUNCTION*-------------------------------------------------------------
*
* Function Name : IP_Sum_immediate
* Returned Value : one's complement checksum
* Comments :
* Returns a one's complement checksum of two numbers.
*
* Note: This function returns 0 iff both summands are 0.
*
*END*-----------------------------------------------------------------*/
uint_16 IP_Sum_immediate
(
uint_16 sum,
/* [IN] initial sum */
uint_16 immediate
/* [IN] number to add to sum */
)
{ /* Body */
uint_32 total = sum & 0xFFFF;
total += immediate & 0xFFFF;
sum = (total >> 16) & 0xFFFF;
total = (total & 0xFFFF) + sum;
return total;
} /* Endbody */
/*FUNCTION*-------------------------------------------------------------
*
* Function Name : IP_Sum_PCB
* Returned Value : one's complement checksum
* Comments :
* Returns a one's complement checksum over all fragments in a PCB.
*
* Note: This function returns 0 iff all summands are 0.
*
*END*-----------------------------------------------------------------*/
uint_16 IP_Sum_PCB
(
uint_16 sum,
/* [IN] initial sum */
RTCSPCB_PTR pcb
/* [IN] the PCB */
)
{ /* Body */
PCB_FRAGMENT_PTR frag = &pcb->PCBPTR->FRAG[1];
uint_32 is_odd = pcb->HEADER_FRAG_USED & 1;
sum = _mem_sum_ip(sum, pcb->HEADER_FRAG_USED, RTCSPCB_DATA(pcb));
while (frag->LENGTH) {
if (is_odd) {
/* If previous fragment was odd, add in first byte in lower 8 bits */
sum = IP_Sum_immediate(sum, frag->FRAGMENT[0] & 0xFF);
} /* Endif */
sum = _mem_sum_ip(sum, frag->LENGTH - is_odd, frag->FRAGMENT + is_odd);
is_odd = (frag->LENGTH - is_odd) & 1;
frag++;
} /* Endwhile */
return sum;
} /* Endbody */
/*FUNCTION*-------------------------------------------------------------
*
* Function Name : IP_Sum_pseudo
* Returned Value : one's complement checksum
* Comments :
* Returns a one's complement checksum of the IP pseudo header
*
* Note: This function returns 0 iff all summands are 0.
*
*END*-----------------------------------------------------------------*/
#if RTCSCFG_ENABLE_IP4
uint_16 IP_Sum_pseudo
(
uint_16 sum,
/* [IN] initial sum */
RTCSPCB_PTR pcb,
/* [IN] the PCB */
int_32 layer
/* [IN] IP layer, relative to current */
)
{ /* Body */
IP_HEADER_PTR iphead = (IP_HEADER_PTR)RTCSPCB_DATA_NETWORK(pcb);
uint_16 protocol;
protocol = RTCSPCB_TRANSPORT_PROTL(pcb);
sum = _mem_sum_ip(sum, 8, iphead->SOURCE); /* source and dest */
sum = IP_Sum_immediate(sum, protocol); /* protocol */
return sum;
} /* Endbody */
#endif /* RTCSCFG_ENABLE_IP4 */
/* EOF */