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/* $NetBSD: in_cksum.c,v 1.8 1998/08/15 10:18:17 mycroft Exp $ */ /*- * Copyright (c) 1998 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Charles M. Hannum. * * 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 NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /*- * Copyright (c) 1990 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. * * from tahoe: in_cksum.c 1.2 86/01/05 * @(#)in_cksum.c 1.3 (Berkeley) 1/19/91 */ #include <sys/param.h> #include <sys/systm.h> #include <sys/mbuf.h> #include <netinet/in.h> /* * Checksum routine for Internet Protocol family headers. * * This routine is very heavily used in the network * code and should be modified for each CPU to be as fast as possible. * * This implementation is the ns32k version. */ #define REDUCE {sum = (sum & 0xffff) + (sum >> 16);} #define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;} #define SWAP {sum <<= 8;} #define ADVANCE(x) {w += x; mlen -= x;} /* * Thanks to gcc we don't have to guess * which registers contain sum & w. */ #define Asm __asm __volatile #define ADD(n) Asm("addd " #n "(%2),%0" : "=r" (sum) : "0" (sum), "r" (w)) #define ADC(n) Asm("addcd " #n "(%2),%0" : "=r" (sum) : "0" (sum), "r" (w)) #define MOP Asm("addcd 0,%0" : "=r" (sum) : "0" (sum)) #define UNSWAP Asm("rotd 8,%0" : "=r" (sum) : "0" (sum)) #define ADDBYTE {sum += *w; SWAP; byte_swapped ^= 1;} #define ADDWORD {sum += *(u_short *)w;} int in_cksum(m, len) register struct mbuf *m; register int len; { register u_char *w; register unsigned sum = 0; register int mlen = 0; int byte_swapped = 0; for (; m && len; m = m->m_next) { mlen = m->m_len; if (mlen == 0) continue; w = mtod(m, u_char *); if (len < mlen) mlen = len; len -= mlen; if (mlen < 16) goto short_mbuf; /* * Force to long boundary so we do longword aligned * memory operations */ if ((3 & (long)w) != 0) { REDUCE; if ((1 & (long)w) != 0) { ADDBYTE; ADVANCE(1); } if ((2 & (long)w) != 0) { ADDWORD; ADVANCE(2); } } /* * Align 4 bytes past a 16-byte cache line boundary. */ if ((4 & (long)w) == 0) { ADD(0); MOP; ADVANCE(4); } if ((8 & (long)w) != 0) { ADD(0); ADC(4); MOP; ADVANCE(8); } /* * Do as much of the checksum as possible 32 bits at at time. * In fact, this loop is unrolled to make overhead from * branches &c small. */ while (mlen >= 32) { /* * Add with carry 16 words and fold in the last carry * by adding a 0 with carry. * * Use the burst fill delay for pointer update. */ ADD(0); ADC(4); ADC(8); ADC(12); MOP; w += 32; ADD(-16); ADC(-12); ADC(-8); ADC(-4); MOP; mlen -= 32; } if (mlen >= 16) { ADD(12); ADC(0); ADC(4); ADC(8); MOP; ADVANCE(16); } short_mbuf: if (mlen >= 8) { ADD(0); ADC(4); MOP; ADVANCE(8); } if (mlen >= 4) { ADD(0); MOP; ADVANCE(4); } if (mlen > 0) { REDUCE; if (mlen >= 2) { ADDWORD; ADVANCE(2); } if (mlen >= 1) { ADDBYTE; } } } if (len) printf("cksum: out of data\n"); if (byte_swapped) { UNSWAP; } REDUCE; ADDCARRY; return (sum ^ 0xffff); }