/* $NetBSD: in_cksum.c,v 1.7 1997/09/02 13:18:15 thorpej Exp $ */ /*- * Copyright (c) 1988, 1992, 1993 * The Regents of the University of California. All rights reserved. * Copyright (c) 1996 * Matt Thomas * * 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. * * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93 */ #include /* RCS ID & Copyright macro defns */ __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include /* * Checksum routine for Internet Protocol family headers * (Portable Alpha version). * * 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) (x > 65535 ? x -= 65535 : x) #define REDUCE32 \ { \ q_util.q = sum; \ sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ } #define REDUCE16 \ { \ q_util.q = sum; \ l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \ sum = l_util.s[0] + l_util.s[1]; \ ADDCARRY(sum); \ } static const u_int32_t in_masks[] = { /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/ 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */ 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */ 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */ 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */ }; union l_util { u_int16_t s[2]; u_int32_t l; }; union q_util { u_int16_t s[4]; u_int32_t l[2]; u_int64_t q; }; static u_int64_t in_cksumdata(const void *buf, int len) { const u_int32_t *lw = (const u_int32_t *) buf; u_int64_t sum = 0; u_int64_t prefilled; int offset; union q_util q_util; if ((3 & (long) lw) == 0 && len == 20) { sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4]; REDUCE32; return sum; } if ((offset = 3 & (long) lw) != 0) { const u_int32_t *masks = in_masks + (offset << 2); lw = (u_int32_t *) (((long) lw) - offset); sum = *lw++ & masks[len >= 3 ? 3 : len]; len -= 4 - offset; if (len <= 0) { REDUCE32; return sum; } } #if 0 /* * Force to cache line boundary. */ offset = 32 - (0x1f & (long) lw); if (offset < 32 && len > offset) { len -= offset; if (4 & offset) { sum += (u_int64_t) lw[0]; lw += 1; } if (8 & offset) { sum += (u_int64_t) lw[0] + lw[1]; lw += 2; } if (16 & offset) { sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; lw += 4; } } #endif /* * access prefilling to start load of next cache line. * then add current cache line * save result of prefilling for loop iteration. */ prefilled = lw[0]; while ((len -= 32) >= 4) { u_int64_t prefilling = lw[8]; sum += prefilled + lw[1] + lw[2] + lw[3] + lw[4] + lw[5] + lw[6] + lw[7]; lw += 8; prefilled = prefilling; } if (len >= 0) { sum += prefilled + lw[1] + lw[2] + lw[3] + lw[4] + lw[5] + lw[6] + lw[7]; lw += 8; } else { len += 32; } while ((len -= 16) >= 0) { sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3]; lw += 4; } len += 16; while ((len -= 4) >= 0) { sum += (u_int64_t) *lw++; } len += 4; if (len > 0) sum += (u_int64_t) (in_masks[len] & *lw); REDUCE32; return sum; } u_short in_addword(u_short a, u_short b) { u_int64_t sum = a + b; ADDCARRY(sum); return (sum); } u_short in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c) { u_int64_t sum; union q_util q_util; union l_util l_util; sum = (u_int64_t) a + b + c; REDUCE16; return (sum); } u_short in_cksum_skip(struct mbuf *m, int len, int skip) { u_int64_t sum = 0; int mlen = 0; int clen = 0; caddr_t addr; union q_util q_util; union l_util l_util; len -= skip; for (; skip && m; m = m->m_next) { if (m->m_len > skip) { mlen = m->m_len - skip; addr = mtod(m, caddr_t) + skip; goto skip_start; } else { skip -= m->m_len; } } for (; m && len; m = m->m_next) { if (m->m_len == 0) continue; mlen = m->m_len; addr = mtod(m, caddr_t); skip_start: if (len < mlen) mlen = len; if ((clen ^ (long) addr) & 1) sum += in_cksumdata(addr, mlen) << 8; else sum += in_cksumdata(addr, mlen); clen += mlen; len -= mlen; } REDUCE16; return (~sum & 0xffff); } u_int in_cksum_hdr(const struct ip *ip) { u_int64_t sum = in_cksumdata(ip, sizeof(struct ip)); union q_util q_util; union l_util l_util; REDUCE16; return (~sum & 0xffff); }