/* * Copyright (c) 2000 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) 1982, 1992, 1993 * The Regents of the University of California. 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)ns_cksum.c 8.1 (Berkeley) 6/10/93 */ #include <sys/param.h> #include <sys/mbuf.h> /* * Checksum routine for Network Systems Protocol Packets (Big-Endian). * * This routine is very heavily used in the network * code and should be modified for each CPU to be as fast as possible. */ #define ADDCARRY(x) { if ((x) > 65535) (x) -= 65535; } #define FOLD(x) {l_util.l = (x); (x) = l_util.s[0] + l_util.s[1]; ADDCARRY(x);} u_short ns_cksum(m, len) register struct mbuf *m; register int len; { register u_short *w; register int sum = 0; register int mlen = 0; register int sum2; union { u_short s[2]; long l; } l_util; for (;m && len; m = m->m_next) { if (m->m_len == 0) continue; /* * Each trip around loop adds in * word from one mbuf segment. */ w = mtod(m, u_short *); if (mlen == -1) { /* * There is a byte left from the last segment; * ones-complement add it into the checksum. */ #if BYTE_ORDER == BIG_ENDIAN sum += *(u_char *)w; #else sum += *(u_char *)w << 8; #endif sum += sum; w = (u_short *)(1 + (char *)w); mlen = m->m_len - 1; len--; FOLD(sum); } else mlen = m->m_len; if (len < mlen) mlen = len; len -= mlen; /* * We can do a 16 bit ones complement sum using * 32 bit arithmetic registers for adding, * with carries from the low added * into the high (by normal carry-chaining) * so long as we fold back before 16 carries have occured. */ if (1 & (int) w) goto uuuuglyy; #ifndef TINY /* -DTINY reduces the size from 1250 to 550, but slows it down by 22% */ while ((mlen -= 32) >= 0) { sum += w[0]; sum += sum; sum += w[1]; sum += sum; sum += w[2]; sum += sum; sum += w[3]; sum += sum; sum += w[4]; sum += sum; sum += w[5]; sum += sum; sum += w[6]; sum += sum; sum += w[7]; sum += sum; FOLD(sum); sum += w[8]; sum += sum; sum += w[9]; sum += sum; sum += w[10]; sum += sum; sum += w[11]; sum += sum; sum += w[12]; sum += sum; sum += w[13]; sum += sum; sum += w[14]; sum += sum; sum += w[15]; sum += sum; FOLD(sum); w += 16; } mlen += 32; #endif while ((mlen -= 8) >= 0) { sum += w[0]; sum += sum; sum += w[1]; sum += sum; sum += w[2]; sum += sum; sum += w[3]; sum += sum; FOLD(sum); w += 4; } mlen += 8; while ((mlen -= 2) >= 0) { sum += *w++; sum += sum; } goto commoncase; uuuuglyy: #if BYTE_ORDER == BIG_ENDIAN #define ww(n) (((u_char *)w)[n + n + 1]) #define vv(n) (((u_char *)w)[n + n]) #else #if BYTE_ORDER == LITTLE_ENDIAN #define vv(n) (((u_char *)w)[n + n + 1]) #define ww(n) (((u_char *)w)[n + n]) #endif #endif sum2 = 0; #ifndef TINY while ((mlen -= 32) >= 0) { sum += ww(0); sum += sum; sum += ww(1); sum += sum; sum += ww(2); sum += sum; sum += ww(3); sum += sum; sum += ww(4); sum += sum; sum += ww(5); sum += sum; sum += ww(6); sum += sum; sum += ww(7); sum += sum; FOLD(sum); sum += ww(8); sum += sum; sum += ww(9); sum += sum; sum += ww(10); sum += sum; sum += ww(11); sum += sum; sum += ww(12); sum += sum; sum += ww(13); sum += sum; sum += ww(14); sum += sum; sum += ww(15); sum += sum; FOLD(sum); sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2; sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2; sum2 += vv(4); sum2 += sum2; sum2 += vv(5); sum2 += sum2; sum2 += vv(6); sum2 += sum2; sum2 += vv(7); sum2 += sum2; FOLD(sum2); sum2 += vv(8); sum2 += sum2; sum2 += vv(9); sum2 += sum2; sum2 += vv(10); sum2 += sum2; sum2 += vv(11); sum2 += sum2; sum2 += vv(12); sum2 += sum2; sum2 += vv(13); sum2 += sum2; sum2 += vv(14); sum2 += sum2; sum2 += vv(15); sum2 += sum2; FOLD(sum2); w += 16; } mlen += 32; #endif while ((mlen -= 8) >= 0) { sum += ww(0); sum += sum; sum += ww(1); sum += sum; sum += ww(2); sum += sum; sum += ww(3); sum += sum; FOLD(sum); sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2; sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2; FOLD(sum2); w += 4; } mlen += 8; while ((mlen -= 2) >= 0) { sum += ww(0); sum += sum; sum2 += vv(0); sum2 += sum2; w++; } sum += (sum2 << 8); commoncase: if (mlen == -1) { #if BYTE_ORDER == BIG_ENDIAN sum += *(u_char *)w << 8; #else sum += *(u_char *)w; #endif } FOLD(sum); } if (mlen == -1) { /* We had an odd number of bytes to sum; assume a garbage byte of zero and clean up */ sum += sum; FOLD(sum); } /* * sum has already been kept to low sixteen bits. * just examine result and exit. */ if(sum==0xffff) sum = 0; return (sum); }