[164] | 1 | /**
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| 2 | * @file
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| 3 | * Incluse internet checksum functions.
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| 4 | *
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| 5 | */
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| 6 |
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| 7 | /*
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| 8 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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| 9 | * All rights reserved.
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| 10 | *
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| 11 | * Redistribution and use in source and binary forms, with or without modification,
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| 12 | * are permitted provided that the following conditions are met:
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| 13 | *
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| 14 | * 1. Redistributions of source code must retain the above copyright notice,
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| 15 | * this list of conditions and the following disclaimer.
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| 16 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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| 17 | * this list of conditions and the following disclaimer in the documentation
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| 18 | * and/or other materials provided with the distribution.
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| 19 | * 3. The name of the author may not be used to endorse or promote products
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| 20 | * derived from this software without specific prior written permission.
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| 21 | *
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| 22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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| 23 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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| 24 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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| 25 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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| 26 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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| 27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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| 29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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| 30 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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| 31 | * OF SUCH DAMAGE.
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| 32 | *
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| 33 | * This file is part of the lwIP TCP/IP stack.
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| 34 | *
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| 35 | * Author: Adam Dunkels <adam@sics.se>
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| 36 | *
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| 37 | */
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| 38 |
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| 39 | #include "lwip/opt.h"
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| 40 |
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| 41 | #include "lwip/inet_chksum.h"
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| 42 | #include "lwip/def.h"
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| 43 |
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| 44 | #include <stddef.h>
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| 45 | #include <string.h>
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| 46 |
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| 47 | /* These are some reference implementations of the checksum algorithm, with the
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| 48 | * aim of being simple, correct and fully portable. Checksumming is the
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| 49 | * first thing you would want to optimize for your platform. If you create
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| 50 | * your own version, link it in and in your cc.h put:
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| 51 | *
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| 52 | * #define LWIP_CHKSUM <your_checksum_routine>
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| 53 | *
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| 54 | * Or you can select from the implementations below by defining
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| 55 | * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
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| 56 | */
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| 57 |
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| 58 | #ifndef LWIP_CHKSUM
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| 59 | # define LWIP_CHKSUM lwip_standard_chksum
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| 60 | # ifndef LWIP_CHKSUM_ALGORITHM
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| 61 | # define LWIP_CHKSUM_ALGORITHM 2
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| 62 | # endif
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| 63 | #endif
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| 64 | /* If none set: */
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| 65 | #ifndef LWIP_CHKSUM_ALGORITHM
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| 66 | # define LWIP_CHKSUM_ALGORITHM 0
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| 67 | #endif
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| 68 |
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| 69 | #if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
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| 70 | /**
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| 71 | * lwip checksum
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| 72 | *
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| 73 | * @param dataptr points to start of data to be summed at any boundary
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| 74 | * @param len length of data to be summed
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| 75 | * @return host order (!) lwip checksum (non-inverted Internet sum)
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| 76 | *
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| 77 | * @note accumulator size limits summable length to 64k
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| 78 | * @note host endianess is irrelevant (p3 RFC1071)
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| 79 | */
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| 80 | static u16_t
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| 81 | lwip_standard_chksum(void *dataptr, u16_t len)
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| 82 | {
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| 83 | u32_t acc;
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| 84 | u16_t src;
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| 85 | u8_t *octetptr;
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| 86 |
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| 87 | acc = 0;
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| 88 | /* dataptr may be at odd or even addresses */
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| 89 | octetptr = (u8_t*)dataptr;
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| 90 | while (len > 1) {
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| 91 | /* declare first octet as most significant
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| 92 | thus assume network order, ignoring host order */
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| 93 | src = (*octetptr) << 8;
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| 94 | octetptr++;
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| 95 | /* declare second octet as least significant */
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| 96 | src |= (*octetptr);
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| 97 | octetptr++;
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| 98 | acc += src;
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| 99 | len -= 2;
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| 100 | }
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| 101 | if (len > 0) {
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| 102 | /* accumulate remaining octet */
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| 103 | src = (*octetptr) << 8;
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| 104 | acc += src;
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| 105 | }
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| 106 | /* add deferred carry bits */
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| 107 | acc = (acc >> 16) + (acc & 0x0000ffffUL);
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| 108 | if ((acc & 0xffff0000UL) != 0) {
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| 109 | acc = (acc >> 16) + (acc & 0x0000ffffUL);
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| 110 | }
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| 111 | /* This maybe a little confusing: reorder sum using htons()
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| 112 | instead of ntohs() since it has a little less call overhead.
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| 113 | The caller must invert bits for Internet sum ! */
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| 114 | return htons((u16_t)acc);
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| 115 | }
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| 116 | #endif
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| 117 |
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| 118 | #if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
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| 119 | /*
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| 120 | * Curt McDowell
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| 121 | * Broadcom Corp.
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| 122 | * csm@broadcom.com
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| 123 | *
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| 124 | * IP checksum two bytes at a time with support for
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| 125 | * unaligned buffer.
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| 126 | * Works for len up to and including 0x20000.
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| 127 | * by Curt McDowell, Broadcom Corp. 12/08/2005
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| 128 | *
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| 129 | * @param dataptr points to start of data to be summed at any boundary
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| 130 | * @param len length of data to be summed
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| 131 | * @return host order (!) lwip checksum (non-inverted Internet sum)
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| 132 | */
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| 133 |
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| 134 | static u16_t
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| 135 | lwip_standard_chksum(void *dataptr, int len)
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| 136 | {
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| 137 | u8_t *pb = (u8_t *)dataptr;
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| 138 | u16_t *ps, t = 0;
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| 139 | u32_t sum = 0;
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| 140 | int odd = ((mem_ptr_t)pb & 1);
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| 141 |
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| 142 | /* Get aligned to u16_t */
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| 143 | if (odd && len > 0) {
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| 144 | ((u8_t *)&t)[1] = *pb++;
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| 145 | len--;
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| 146 | }
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| 147 |
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| 148 | /* Add the bulk of the data */
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| 149 | ps = (u16_t *)(void *)pb;
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| 150 | while (len > 1) {
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| 151 | sum += *ps++;
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| 152 | len -= 2;
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| 153 | }
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| 154 |
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| 155 | /* Consume left-over byte, if any */
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| 156 | if (len > 0) {
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| 157 | ((u8_t *)&t)[0] = *(u8_t *)ps;
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| 158 | }
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| 159 |
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| 160 | /* Add end bytes */
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| 161 | sum += t;
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| 162 |
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| 163 | /* Fold 32-bit sum to 16 bits
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| 164 | calling this twice is propably faster than if statements... */
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| 165 | sum = FOLD_U32T(sum);
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| 166 | sum = FOLD_U32T(sum);
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| 167 |
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| 168 | /* Swap if alignment was odd */
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| 169 | if (odd) {
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| 170 | sum = SWAP_BYTES_IN_WORD(sum);
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| 171 | }
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| 172 |
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| 173 | return (u16_t)sum;
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| 174 | }
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| 175 | #endif
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| 176 |
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| 177 | #if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
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| 178 | /**
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| 179 | * An optimized checksum routine. Basically, it uses loop-unrolling on
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| 180 | * the checksum loop, treating the head and tail bytes specially, whereas
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| 181 | * the inner loop acts on 8 bytes at a time.
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| 182 | *
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| 183 | * @arg start of buffer to be checksummed. May be an odd byte address.
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| 184 | * @len number of bytes in the buffer to be checksummed.
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| 185 | * @return host order (!) lwip checksum (non-inverted Internet sum)
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| 186 | *
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| 187 | * by Curt McDowell, Broadcom Corp. December 8th, 2005
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| 188 | */
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| 189 |
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| 190 | static u16_t
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| 191 | lwip_standard_chksum(void *dataptr, int len)
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| 192 | {
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| 193 | u8_t *pb = (u8_t *)dataptr;
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| 194 | u16_t *ps, t = 0;
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| 195 | u32_t *pl;
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| 196 | u32_t sum = 0, tmp;
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| 197 | /* starts at odd byte address? */
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| 198 | int odd = ((mem_ptr_t)pb & 1);
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| 199 |
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| 200 | if (odd && len > 0) {
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| 201 | ((u8_t *)&t)[1] = *pb++;
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| 202 | len--;
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| 203 | }
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| 204 |
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| 205 | ps = (u16_t *)pb;
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| 206 |
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| 207 | if (((mem_ptr_t)ps & 3) && len > 1) {
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| 208 | sum += *ps++;
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| 209 | len -= 2;
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| 210 | }
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| 211 |
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| 212 | pl = (u32_t *)ps;
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| 213 |
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| 214 | while (len > 7) {
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| 215 | tmp = sum + *pl++; /* ping */
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| 216 | if (tmp < sum) {
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| 217 | tmp++; /* add back carry */
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| 218 | }
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| 219 |
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| 220 | sum = tmp + *pl++; /* pong */
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| 221 | if (sum < tmp) {
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| 222 | sum++; /* add back carry */
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| 223 | }
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| 224 |
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| 225 | len -= 8;
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| 226 | }
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| 227 |
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| 228 | /* make room in upper bits */
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| 229 | sum = FOLD_U32T(sum);
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| 230 |
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| 231 | ps = (u16_t *)pl;
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| 232 |
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| 233 | /* 16-bit aligned word remaining? */
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| 234 | while (len > 1) {
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| 235 | sum += *ps++;
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| 236 | len -= 2;
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| 237 | }
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| 238 |
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| 239 | /* dangling tail byte remaining? */
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| 240 | if (len > 0) { /* include odd byte */
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| 241 | ((u8_t *)&t)[0] = *(u8_t *)ps;
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| 242 | }
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| 243 |
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| 244 | sum += t; /* add end bytes */
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| 245 |
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| 246 | /* Fold 32-bit sum to 16 bits
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| 247 | calling this twice is propably faster than if statements... */
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| 248 | sum = FOLD_U32T(sum);
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| 249 | sum = FOLD_U32T(sum);
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| 250 |
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| 251 | if (odd) {
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| 252 | sum = SWAP_BYTES_IN_WORD(sum);
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| 253 | }
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| 254 |
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| 255 | return (u16_t)sum;
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| 256 | }
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| 257 | #endif
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| 258 |
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| 259 | /* inet_chksum_pseudo:
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| 260 | *
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| 261 | * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
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| 262 | * IP addresses are expected to be in network byte order.
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| 263 | *
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| 264 | * @param p chain of pbufs over that a checksum should be calculated (ip data part)
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| 265 | * @param src source ip address (used for checksum of pseudo header)
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| 266 | * @param dst destination ip address (used for checksum of pseudo header)
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| 267 | * @param proto ip protocol (used for checksum of pseudo header)
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| 268 | * @param proto_len length of the ip data part (used for checksum of pseudo header)
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| 269 | * @return checksum (as u16_t) to be saved directly in the protocol header
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| 270 | */
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| 271 | u16_t
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| 272 | inet_chksum_pseudo(struct pbuf *p,
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| 273 | ip_addr_t *src, ip_addr_t *dest,
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| 274 | u8_t proto, u16_t proto_len)
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| 275 | {
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| 276 | u32_t acc;
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| 277 | u32_t addr;
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| 278 | struct pbuf *q;
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| 279 | u8_t swapped;
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| 280 |
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| 281 | acc = 0;
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| 282 | swapped = 0;
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| 283 | /* iterate through all pbuf in chain */
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| 284 | for(q = p; q != NULL; q = q->next) {
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| 285 | LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
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| 286 | (void *)q, (void *)q->next));
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| 287 | acc += LWIP_CHKSUM(q->payload, q->len);
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| 288 | /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
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| 289 | /* just executing this next line is probably faster that the if statement needed
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| 290 | to check whether we really need to execute it, and does no harm */
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| 291 | acc = FOLD_U32T(acc);
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| 292 | if (q->len % 2 != 0) {
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| 293 | swapped = 1 - swapped;
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| 294 | acc = SWAP_BYTES_IN_WORD(acc);
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| 295 | }
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| 296 | /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
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| 297 | }
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| 298 |
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| 299 | if (swapped) {
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| 300 | acc = SWAP_BYTES_IN_WORD(acc);
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| 301 | }
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| 302 | addr = ip4_addr_get_u32(src);
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| 303 | acc += (addr & 0xffffUL);
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| 304 | acc += ((addr >> 16) & 0xffffUL);
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| 305 | addr = ip4_addr_get_u32(dest);
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| 306 | acc += (addr & 0xffffUL);
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| 307 | acc += ((addr >> 16) & 0xffffUL);
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| 308 | acc += (u32_t)htons((u16_t)proto);
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| 309 | acc += (u32_t)htons(proto_len);
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| 310 |
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| 311 | /* Fold 32-bit sum to 16 bits
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| 312 | calling this twice is propably faster than if statements... */
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| 313 | acc = FOLD_U32T(acc);
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| 314 | acc = FOLD_U32T(acc);
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| 315 | LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
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| 316 | return (u16_t)~(acc & 0xffffUL);
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| 317 | }
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| 318 |
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| 319 | /* inet_chksum_pseudo:
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| 320 | *
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| 321 | * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
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| 322 | * IP addresses are expected to be in network byte order.
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| 323 | *
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| 324 | * @param p chain of pbufs over that a checksum should be calculated (ip data part)
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| 325 | * @param src source ip address (used for checksum of pseudo header)
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| 326 | * @param dst destination ip address (used for checksum of pseudo header)
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| 327 | * @param proto ip protocol (used for checksum of pseudo header)
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| 328 | * @param proto_len length of the ip data part (used for checksum of pseudo header)
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| 329 | * @return checksum (as u16_t) to be saved directly in the protocol header
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| 330 | */
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| 331 | u16_t
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| 332 | inet_chksum_pseudo_partial(struct pbuf *p,
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| 333 | ip_addr_t *src, ip_addr_t *dest,
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| 334 | u8_t proto, u16_t proto_len, u16_t chksum_len)
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| 335 | {
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| 336 | u32_t acc;
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| 337 | u32_t addr;
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| 338 | struct pbuf *q;
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| 339 | u8_t swapped;
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| 340 | u16_t chklen;
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| 341 |
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| 342 | acc = 0;
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| 343 | swapped = 0;
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| 344 | /* iterate through all pbuf in chain */
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| 345 | for(q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
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| 346 | LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
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| 347 | (void *)q, (void *)q->next));
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| 348 | chklen = q->len;
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| 349 | if (chklen > chksum_len) {
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| 350 | chklen = chksum_len;
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| 351 | }
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| 352 | acc += LWIP_CHKSUM(q->payload, chklen);
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| 353 | chksum_len -= chklen;
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| 354 | LWIP_ASSERT("delete me", chksum_len < 0x7fff);
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| 355 | /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
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| 356 | /* fold the upper bit down */
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| 357 | acc = FOLD_U32T(acc);
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| 358 | if (q->len % 2 != 0) {
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| 359 | swapped = 1 - swapped;
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| 360 | acc = SWAP_BYTES_IN_WORD(acc);
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| 361 | }
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| 362 | /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
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| 363 | }
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| 364 |
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| 365 | if (swapped) {
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| 366 | acc = SWAP_BYTES_IN_WORD(acc);
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| 367 | }
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| 368 | addr = ip4_addr_get_u32(src);
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| 369 | acc += (addr & 0xffffUL);
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| 370 | acc += ((addr >> 16) & 0xffffUL);
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| 371 | addr = ip4_addr_get_u32(dest);
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| 372 | acc += (addr & 0xffffUL);
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| 373 | acc += ((addr >> 16) & 0xffffUL);
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| 374 | acc += (u32_t)htons((u16_t)proto);
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| 375 | acc += (u32_t)htons(proto_len);
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| 376 |
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| 377 | /* Fold 32-bit sum to 16 bits
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| 378 | calling this twice is propably faster than if statements... */
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| 379 | acc = FOLD_U32T(acc);
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| 380 | acc = FOLD_U32T(acc);
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| 381 | LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
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| 382 | return (u16_t)~(acc & 0xffffUL);
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| 383 | }
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| 384 |
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| 385 | /* inet_chksum:
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| 386 | *
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| 387 | * Calculates the Internet checksum over a portion of memory. Used primarily for IP
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| 388 | * and ICMP.
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| 389 | *
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| 390 | * @param dataptr start of the buffer to calculate the checksum (no alignment needed)
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| 391 | * @param len length of the buffer to calculate the checksum
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| 392 | * @return checksum (as u16_t) to be saved directly in the protocol header
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| 393 | */
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| 394 |
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| 395 | u16_t
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| 396 | inet_chksum(void *dataptr, u16_t len)
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| 397 | {
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| 398 | return ~LWIP_CHKSUM(dataptr, len);
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| 399 | }
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| 400 |
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| 401 | /**
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| 402 | * Calculate a checksum over a chain of pbufs (without pseudo-header, much like
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| 403 | * inet_chksum only pbufs are used).
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| 404 | *
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| 405 | * @param p pbuf chain over that the checksum should be calculated
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| 406 | * @return checksum (as u16_t) to be saved directly in the protocol header
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| 407 | */
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| 408 | u16_t
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| 409 | inet_chksum_pbuf(struct pbuf *p)
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| 410 | {
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| 411 | u32_t acc;
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| 412 | struct pbuf *q;
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| 413 | u8_t swapped;
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| 414 |
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| 415 | acc = 0;
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| 416 | swapped = 0;
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| 417 | for(q = p; q != NULL; q = q->next) {
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| 418 | acc += LWIP_CHKSUM(q->payload, q->len);
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| 419 | acc = FOLD_U32T(acc);
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| 420 | if (q->len % 2 != 0) {
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| 421 | swapped = 1 - swapped;
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| 422 | acc = SWAP_BYTES_IN_WORD(acc);
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| 423 | }
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| 424 | }
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| 425 |
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| 426 | if (swapped) {
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| 427 | acc = SWAP_BYTES_IN_WORD(acc);
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| 428 | }
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| 429 | return (u16_t)~(acc & 0xffffUL);
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| 430 | }
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| 431 |
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| 432 | /* These are some implementations for LWIP_CHKSUM_COPY, which copies data
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| 433 | * like MEMCPY but generates a checksum at the same time. Since this is a
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| 434 | * performance-sensitive function, you might want to create your own version
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| 435 | * in assembly targeted at your hardware by defining it in lwipopts.h:
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| 436 | * #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len)
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| 437 | */
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| 438 |
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| 439 | #if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */
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| 440 | /** Safe but slow: first call MEMCPY, then call LWIP_CHKSUM.
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| 441 | * For architectures with big caches, data might still be in cache when
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| 442 | * generating the checksum after copying.
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| 443 | */
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| 444 | u16_t
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| 445 | lwip_chksum_copy(void *dst, const void *src, u16_t len)
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| 446 | {
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| 447 | MEMCPY(dst, src, len);
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| 448 | return LWIP_CHKSUM(dst, len);
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| 449 | }
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| 450 | #endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */
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