| /* $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 <matt@3am-software.com> |
| * |
| * 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 <sys/bsd_cdefs.h> /* RCS ID & Copyright macro defns */ |
| //__FBSDID("$FreeBSD$"); |
| |
| #include <sys/bsd_param.h> |
| #include <sys/bsd_mbuf.h> |
| #include <sys/bsd_systm.h> |
| #include <netinet/bsd_in_systm.h> |
| #include <netinet/bsd_in.h> |
| #include <netinet/bsd_ip.h> |
| #include <machine/bsd_in_cksum.h> |
| |
| /* |
| * 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); |
| } |
