+++ /dev/null
-/*
- * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-/*-
- * Copyright (c) 2001 Charles Mott <cmott@scientech.com>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS 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 THE AUTHOR OR 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.
- *
- * Based upon:
- * $FreeBSD: src/lib/libalias/alias_util.c,v 1.4.2.2 2001/06/04 14:59:06 brian Exp $
- */
-
-/*
- Alias_util.c contains general utilities used by other functions
- in the packet aliasing module. At the moment, there are functions
- for computing IP header and TCP packet checksums.
-
- The checksum routines are based upon example code in a Unix networking
- text written by Stevens (sorry, I can't remember the title -- but
- at least this is a good author).
-
- Initial Version: August, 1996 (cjm)
-
- Version 1.7: January 9, 1997
- Added differential checksum update function.
-*/
-
-/*
-Note: the checksum routines assume that the actual checksum word has
-been zeroed out. If the checksum word is filled with the proper value,
-then these routines will give a result of zero (useful for testing
-purposes);
-*/
-
-#include <sys/types.h>
-#include <netinet/in_systm.h>
-#include <netinet/in.h>
-#include <netinet/ip.h>
-#include <netinet/tcp.h>
-
-#include "alias.h"
-#include "alias_local.h"
-
-u_short
-PacketAliasInternetChecksum(u_short *ptr, int nbytes)
-{
- int sum, oddbyte;
-
- sum = 0;
- while (nbytes > 1)
- {
- sum += *ptr++;
- nbytes -= 2;
- }
- if (nbytes == 1)
- {
- oddbyte = 0;
- ((u_char *) &oddbyte)[0] = *(u_char *) ptr;
- ((u_char *) &oddbyte)[1] = 0;
- sum += oddbyte;
- }
- sum = (sum >> 16) + (sum & 0xffff);
- sum += (sum >> 16);
- return(~sum);
-}
-
-u_short
-IpChecksum(struct ip *pip)
-{
- return( PacketAliasInternetChecksum((u_short *) pip,
- (pip->ip_hl << 2)) );
-
-}
-
-u_short
-TcpChecksum(struct ip *pip)
-{
- u_short *ptr;
- struct tcphdr *tc;
- int nhdr, ntcp, nbytes;
- int sum, oddbyte;
-
- nhdr = pip->ip_hl << 2;
- ntcp = ntohs(pip->ip_len) - nhdr;
-
- tc = (struct tcphdr *) ((char *) pip + nhdr);
- ptr = (u_short *) tc;
-
-/* Add up TCP header and data */
- nbytes = ntcp;
- sum = 0;
- while (nbytes > 1)
- {
- sum += *ptr++;
- nbytes -= 2;
- }
- if (nbytes == 1)
- {
- oddbyte = 0;
- ((u_char *) &oddbyte)[0] = *(u_char *) ptr;
- ((u_char *) &oddbyte)[1] = 0;
- sum += oddbyte;
- }
-
-/* "Pseudo-header" data */
- ptr = (u_short *) &(pip->ip_dst);
- sum += *ptr++;
- sum += *ptr;
- ptr = (u_short *) &(pip->ip_src);
- sum += *ptr++;
- sum += *ptr;
- sum += htons((u_short) ntcp);
- sum += htons((u_short) pip->ip_p);
-
-/* Roll over carry bits */
- sum = (sum >> 16) + (sum & 0xffff);
- sum += (sum >> 16);
-
-/* Return checksum */
- return((u_short) ~sum);
-}
-
-
-void
-DifferentialChecksum(u_short *cksum, u_short *new, u_short *old, int n)
-{
- int i;
- int accumulate;
-
- accumulate = *cksum;
- for (i=0; i<n; i++)
- {
- accumulate -= *new++;
- accumulate += *old++;
- }
-
- if (accumulate < 0)
- {
- accumulate = -accumulate;
- accumulate = (accumulate >> 16) + (accumulate & 0xffff);
- accumulate += accumulate >> 16;
- *cksum = (u_short) ~accumulate;
- }
- else
- {
- accumulate = (accumulate >> 16) + (accumulate & 0xffff);
- accumulate += accumulate >> 16;
- *cksum = (u_short) accumulate;
- }
-}
-
projects / apple / network_cmds.git / blobdiff