mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-16 10:20:30 +00:00
95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
/*
|
|
*
|
|
* ===================================
|
|
* HARP | Host ATM Research Platform
|
|
* ===================================
|
|
*
|
|
*
|
|
* This Host ATM Research Platform ("HARP") file (the "Software") is
|
|
* made available by Network Computing Services, Inc. ("NetworkCS")
|
|
* "AS IS". NetworkCS does not provide maintenance, improvements or
|
|
* support of any kind.
|
|
*
|
|
* NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED,
|
|
* INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
* AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE
|
|
* SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE.
|
|
* In no event shall NetworkCS be responsible for any damages, including
|
|
* but not limited to consequential damages, arising from or relating to
|
|
* any use of the Software or related support.
|
|
*
|
|
* Copyright 1994-1998 Network Computing Services, Inc.
|
|
*
|
|
* Copies of this Software may be made, however, the above copyright
|
|
* notice must be reproduced on all copies.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
/*
|
|
* User Space Library Functions
|
|
* ----------------------------
|
|
*
|
|
* IP checksum computation
|
|
*
|
|
*/
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/param.h>
|
|
#include <sys/socket.h>
|
|
#include <net/if.h>
|
|
#include <netinet/in.h>
|
|
#include <netatm/port.h>
|
|
#include <netatm/atm.h>
|
|
#include <netatm/atm_if.h>
|
|
#include <netatm/atm_sap.h>
|
|
#include <netatm/atm_sys.h>
|
|
#include <netatm/atm_ioctl.h>
|
|
|
|
#include "libatm.h"
|
|
|
|
/*
|
|
* Compute an IP checksum
|
|
*
|
|
* This code was taken from RFC 1071.
|
|
*
|
|
* "The following "C" code algorithm computes the checksum with an inner
|
|
* loop that sums 16 bits at a time in a 32-bit accumulator."
|
|
*
|
|
* Arguments:
|
|
* addr pointer to the buffer whose checksum is to be computed
|
|
* count number of bytes to include in the checksum
|
|
*
|
|
* Returns:
|
|
* the computed checksum
|
|
*
|
|
*/
|
|
short
|
|
ip_checksum(addr, count)
|
|
char *addr;
|
|
int count;
|
|
{
|
|
/* Compute Internet Checksum for "count" bytes
|
|
* beginning at location "addr".
|
|
*/
|
|
long sum = 0;
|
|
|
|
while( count > 1 ) {
|
|
/* This is the inner loop */
|
|
sum += ntohs(* (unsigned short *) addr);
|
|
addr += sizeof(unsigned short);
|
|
count -= sizeof(unsigned short);
|
|
}
|
|
|
|
/* Add left-over byte, if any */
|
|
if( count > 0 )
|
|
sum += * (unsigned char *) addr;
|
|
|
|
/* Fold 32-bit sum to 16 bits */
|
|
while (sum>>16)
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
return((short)~sum);
|
|
}
|