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- /* $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
- */
- /*
- * 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.
- */
- #include <u.h>
- #include <libc.h>
- #include <ip.h>
- #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 uint32_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 {
- uint16_t s[2];
- uint32_t l;
- };
- union q_util {
- uint16_t s[4];
- uint32_t l[2];
- uint64_t q;
- };
- static uint64_t
- in_cksumdata(const void *buf, int len)
- {
- const uint32_t *lw = (const uint32_t *) buf;
- uint64_t sum = 0;
- uint64_t prefilled;
- int offset;
- union q_util q_util;
- if ((3 & (long) lw) == 0 && len == 20) {
- sum = (uint64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
- REDUCE32;
- return sum;
- }
- if ((offset = 3 & (long) lw) != 0) {
- const uint32_t *masks = in_masks + (offset << 2);
- lw = (uint32_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 += (uint64_t) lw[0];
- lw += 1;
- }
- if (8 & offset) {
- sum += (uint64_t) lw[0] + lw[1];
- lw += 2;
- }
- if (16 & offset) {
- sum += (uint64_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) {
- uint64_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 += (uint64_t) lw[0] + lw[1] + lw[2] + lw[3];
- lw += 4;
- }
- len += 16;
- while ((len -= 4) >= 0) {
- sum += (uint64_t) *lw++;
- }
- len += 4;
- if (len > 0)
- sum += (uint64_t) (in_masks[len] & *lw);
- REDUCE32;
- return sum;
- }
- uint16_t ptclbsum(uint8_t * addr, int len)
- {
- uint64_t sum = in_cksumdata(addr, len);
- union q_util q_util;
- union l_util l_util;
- REDUCE16;
- return ((sum & (uint16_t)0x00ffU) << 8) |
- ((sum & (uint16_t)0xff00U) >> 8);
- }
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