451 lines
13 KiB
C
451 lines
13 KiB
C
/**
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* @file
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* Incluse internet checksum functions.
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*
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*/
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/*
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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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*/
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#include "lwip/opt.h"
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#include "lwip/inet_chksum.h"
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#include "lwip/def.h"
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#include <stddef.h>
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#include <string.h>
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/* These are some reference implementations of the checksum algorithm, with the
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* aim of being simple, correct and fully portable. Checksumming is the
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* first thing you would want to optimize for your platform. If you create
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* your own version, link it in and in your cc.h put:
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*
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* #define LWIP_CHKSUM <your_checksum_routine>
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*
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* Or you can select from the implementations below by defining
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* LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
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*/
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#ifndef LWIP_CHKSUM
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# define LWIP_CHKSUM lwip_standard_chksum
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# ifndef LWIP_CHKSUM_ALGORITHM
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# define LWIP_CHKSUM_ALGORITHM 2
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# endif
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#endif
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/* If none set: */
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#ifndef LWIP_CHKSUM_ALGORITHM
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# define LWIP_CHKSUM_ALGORITHM 0
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#endif
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#if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
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/**
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* lwip checksum
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*
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* @param dataptr points to start of data to be summed at any boundary
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* @param len length of data to be summed
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* @return host order (!) lwip checksum (non-inverted Internet sum)
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*
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* @note accumulator size limits summable length to 64k
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* @note host endianess is irrelevant (p3 RFC1071)
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*/
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static u16_t
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lwip_standard_chksum(void *dataptr, u16_t len)
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{
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u32_t acc;
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u16_t src;
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u8_t *octetptr;
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acc = 0;
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/* dataptr may be at odd or even addresses */
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octetptr = (u8_t*)dataptr;
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while (len > 1) {
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/* declare first octet as most significant
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thus assume network order, ignoring host order */
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src = (*octetptr) << 8;
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octetptr++;
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/* declare second octet as least significant */
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src |= (*octetptr);
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octetptr++;
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acc += src;
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len -= 2;
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}
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if (len > 0) {
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/* accumulate remaining octet */
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src = (*octetptr) << 8;
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acc += src;
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}
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/* add deferred carry bits */
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acc = (acc >> 16) + (acc & 0x0000ffffUL);
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if ((acc & 0xffff0000UL) != 0) {
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acc = (acc >> 16) + (acc & 0x0000ffffUL);
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}
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/* This maybe a little confusing: reorder sum using htons()
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instead of ntohs() since it has a little less call overhead.
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The caller must invert bits for Internet sum ! */
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return htons((u16_t)acc);
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}
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#endif
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#if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
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/*
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* Curt McDowell
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* Broadcom Corp.
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* csm@broadcom.com
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*
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* IP checksum two bytes at a time with support for
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* unaligned buffer.
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* Works for len up to and including 0x20000.
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* by Curt McDowell, Broadcom Corp. 12/08/2005
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*
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* @param dataptr points to start of data to be summed at any boundary
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* @param len length of data to be summed
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* @return host order (!) lwip checksum (non-inverted Internet sum)
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*/
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static u16_t
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lwip_standard_chksum(void *dataptr, int len)
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{
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u8_t *pb = (u8_t *)dataptr;
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u16_t *ps, t = 0;
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u32_t sum = 0;
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int odd = ((mem_ptr_t)pb & 1);
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/* Get aligned to u16_t */
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if (odd && len > 0) {
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((u8_t *)&t)[1] = *pb++;
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len--;
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}
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/* Add the bulk of the data */
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ps = (u16_t *)(void *)pb;
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while (len > 1) {
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sum += *ps++;
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len -= 2;
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}
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/* Consume left-over byte, if any */
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if (len > 0) {
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((u8_t *)&t)[0] = *(u8_t *)ps;
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}
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/* Add end bytes */
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sum += t;
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/* Fold 32-bit sum to 16 bits
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calling this twice is propably faster than if statements... */
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sum = FOLD_U32T(sum);
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sum = FOLD_U32T(sum);
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/* Swap if alignment was odd */
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if (odd) {
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sum = SWAP_BYTES_IN_WORD(sum);
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}
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return (u16_t)sum;
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}
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#endif
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#if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
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/**
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* An optimized checksum routine. Basically, it uses loop-unrolling on
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* the checksum loop, treating the head and tail bytes specially, whereas
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* the inner loop acts on 8 bytes at a time.
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*
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* @arg start of buffer to be checksummed. May be an odd byte address.
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* @len number of bytes in the buffer to be checksummed.
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* @return host order (!) lwip checksum (non-inverted Internet sum)
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*
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* by Curt McDowell, Broadcom Corp. December 8th, 2005
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*/
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static u16_t
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lwip_standard_chksum(void *dataptr, int len)
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{
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u8_t *pb = (u8_t *)dataptr;
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u16_t *ps, t = 0;
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u32_t *pl;
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u32_t sum = 0, tmp;
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/* starts at odd byte address? */
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int odd = ((mem_ptr_t)pb & 1);
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if (odd && len > 0) {
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((u8_t *)&t)[1] = *pb++;
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len--;
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}
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ps = (u16_t *)pb;
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if (((mem_ptr_t)ps & 3) && len > 1) {
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sum += *ps++;
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len -= 2;
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}
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pl = (u32_t *)ps;
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while (len > 7) {
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tmp = sum + *pl++; /* ping */
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if (tmp < sum) {
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tmp++; /* add back carry */
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}
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sum = tmp + *pl++; /* pong */
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if (sum < tmp) {
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sum++; /* add back carry */
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}
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len -= 8;
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}
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/* make room in upper bits */
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sum = FOLD_U32T(sum);
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ps = (u16_t *)pl;
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/* 16-bit aligned word remaining? */
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while (len > 1) {
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sum += *ps++;
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len -= 2;
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}
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/* dangling tail byte remaining? */
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if (len > 0) { /* include odd byte */
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((u8_t *)&t)[0] = *(u8_t *)ps;
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}
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sum += t; /* add end bytes */
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/* Fold 32-bit sum to 16 bits
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calling this twice is propably faster than if statements... */
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sum = FOLD_U32T(sum);
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sum = FOLD_U32T(sum);
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if (odd) {
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sum = SWAP_BYTES_IN_WORD(sum);
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}
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return (u16_t)sum;
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}
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#endif
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/* inet_chksum_pseudo:
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*
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* Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
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* IP addresses are expected to be in network byte order.
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*
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* @param p chain of pbufs over that a checksum should be calculated (ip data part)
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* @param src source ip address (used for checksum of pseudo header)
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* @param dst destination ip address (used for checksum of pseudo header)
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* @param proto ip protocol (used for checksum of pseudo header)
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* @param proto_len length of the ip data part (used for checksum of pseudo header)
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* @return checksum (as u16_t) to be saved directly in the protocol header
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*/
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u16_t
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inet_chksum_pseudo(struct pbuf *p,
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ip_addr_t *src, ip_addr_t *dest,
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u8_t proto, u16_t proto_len)
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{
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u32_t acc;
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u32_t addr;
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struct pbuf *q;
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u8_t swapped;
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acc = 0;
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swapped = 0;
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/* iterate through all pbuf in chain */
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for(q = p; q != NULL; q = q->next) {
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LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
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(void *)q, (void *)q->next));
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acc += LWIP_CHKSUM(q->payload, q->len);
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/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
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/* just executing this next line is probably faster that the if statement needed
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to check whether we really need to execute it, and does no harm */
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acc = FOLD_U32T(acc);
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if (q->len % 2 != 0) {
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swapped = 1 - swapped;
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
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}
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if (swapped) {
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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addr = ip4_addr_get_u32(src);
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acc += (addr & 0xffffUL);
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acc += ((addr >> 16) & 0xffffUL);
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addr = ip4_addr_get_u32(dest);
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acc += (addr & 0xffffUL);
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acc += ((addr >> 16) & 0xffffUL);
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acc += (u32_t)htons((u16_t)proto);
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acc += (u32_t)htons(proto_len);
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/* Fold 32-bit sum to 16 bits
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calling this twice is propably faster than if statements... */
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acc = FOLD_U32T(acc);
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acc = FOLD_U32T(acc);
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LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
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return (u16_t)~(acc & 0xffffUL);
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}
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/* inet_chksum_pseudo:
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*
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* Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
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* IP addresses are expected to be in network byte order.
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*
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* @param p chain of pbufs over that a checksum should be calculated (ip data part)
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* @param src source ip address (used for checksum of pseudo header)
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* @param dst destination ip address (used for checksum of pseudo header)
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* @param proto ip protocol (used for checksum of pseudo header)
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* @param proto_len length of the ip data part (used for checksum of pseudo header)
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* @return checksum (as u16_t) to be saved directly in the protocol header
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*/
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u16_t
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inet_chksum_pseudo_partial(struct pbuf *p,
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ip_addr_t *src, ip_addr_t *dest,
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u8_t proto, u16_t proto_len, u16_t chksum_len)
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{
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u32_t acc;
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u32_t addr;
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struct pbuf *q;
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u8_t swapped;
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u16_t chklen;
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acc = 0;
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swapped = 0;
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/* iterate through all pbuf in chain */
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for(q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
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LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
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(void *)q, (void *)q->next));
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chklen = q->len;
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if (chklen > chksum_len) {
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chklen = chksum_len;
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}
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acc += LWIP_CHKSUM(q->payload, chklen);
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chksum_len -= chklen;
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LWIP_ASSERT("delete me", chksum_len < 0x7fff);
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/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
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/* fold the upper bit down */
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acc = FOLD_U32T(acc);
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if (q->len % 2 != 0) {
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swapped = 1 - swapped;
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
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}
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if (swapped) {
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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addr = ip4_addr_get_u32(src);
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acc += (addr & 0xffffUL);
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acc += ((addr >> 16) & 0xffffUL);
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addr = ip4_addr_get_u32(dest);
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acc += (addr & 0xffffUL);
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acc += ((addr >> 16) & 0xffffUL);
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acc += (u32_t)htons((u16_t)proto);
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acc += (u32_t)htons(proto_len);
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/* Fold 32-bit sum to 16 bits
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calling this twice is propably faster than if statements... */
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acc = FOLD_U32T(acc);
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acc = FOLD_U32T(acc);
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LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
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return (u16_t)~(acc & 0xffffUL);
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}
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/* inet_chksum:
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*
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* Calculates the Internet checksum over a portion of memory. Used primarily for IP
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* and ICMP.
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*
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* @param dataptr start of the buffer to calculate the checksum (no alignment needed)
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* @param len length of the buffer to calculate the checksum
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* @return checksum (as u16_t) to be saved directly in the protocol header
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*/
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u16_t
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inet_chksum(void *dataptr, u16_t len)
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{
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return ~LWIP_CHKSUM(dataptr, len);
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}
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/**
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* Calculate a checksum over a chain of pbufs (without pseudo-header, much like
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* inet_chksum only pbufs are used).
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*
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* @param p pbuf chain over that the checksum should be calculated
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* @return checksum (as u16_t) to be saved directly in the protocol header
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*/
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u16_t
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inet_chksum_pbuf(struct pbuf *p)
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{
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u32_t acc;
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struct pbuf *q;
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u8_t swapped;
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acc = 0;
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swapped = 0;
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for(q = p; q != NULL; q = q->next) {
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acc += LWIP_CHKSUM(q->payload, q->len);
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acc = FOLD_U32T(acc);
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if (q->len % 2 != 0) {
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swapped = 1 - swapped;
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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}
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if (swapped) {
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acc = SWAP_BYTES_IN_WORD(acc);
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}
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return (u16_t)~(acc & 0xffffUL);
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}
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/* These are some implementations for LWIP_CHKSUM_COPY, which copies data
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* like MEMCPY but generates a checksum at the same time. Since this is a
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* performance-sensitive function, you might want to create your own version
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* in assembly targeted at your hardware by defining it in lwipopts.h:
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* #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len)
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*/
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#if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */
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/** Safe but slow: first call MEMCPY, then call LWIP_CHKSUM.
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* For architectures with big caches, data might still be in cache when
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* generating the checksum after copying.
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*/
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u16_t
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lwip_chksum_copy(void *dst, const void *src, u16_t len)
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{
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MEMCPY(dst, src, len);
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return LWIP_CHKSUM(dst, len);
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}
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#endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */
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