| /** |
| * @file |
| * Internet checksum functions.\n |
| * |
| * These are some reference implementations of the checksum algorithm, with the |
| * aim of being simple, correct and fully portable. Checksumming is the |
| * first thing you would want to optimize for your platform. If you create |
| * your own version, link it in and in your cc.h put: |
| * |
| * \#define LWIP_CHKSUM your_checksum_routine |
| * |
| * Or you can select from the implementations below by defining |
| * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3. |
| */ |
| |
| /* |
| * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
| * All rights reserved. |
| * |
| * 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. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. |
| * |
| * This file is part of the lwIP TCP/IP stack. |
| * |
| * Author: Adam Dunkels <adam@sics.se> |
| * |
| */ |
| |
| #include "lwip/opt.h" |
| |
| #include "lwip/inet_chksum.h" |
| #include "lwip/def.h" |
| #include "lwip/ip_addr.h" |
| |
| #include <string.h> |
| |
| #ifndef LWIP_CHKSUM |
| # define LWIP_CHKSUM lwip_standard_chksum |
| # ifndef LWIP_CHKSUM_ALGORITHM |
| # define LWIP_CHKSUM_ALGORITHM 2 |
| # endif |
| u16_t lwip_standard_chksum(const void *dataptr, int len); |
| #endif |
| /* If none set: */ |
| #ifndef LWIP_CHKSUM_ALGORITHM |
| # define LWIP_CHKSUM_ALGORITHM 0 |
| #endif |
| |
| #if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */ |
| /** |
| * lwip checksum |
| * |
| * @param dataptr points to start of data to be summed at any boundary |
| * @param len length of data to be summed |
| * @return host order (!) lwip checksum (non-inverted Internet sum) |
| * |
| * @note accumulator size limits summable length to 64k |
| * @note host endianess is irrelevant (p3 RFC1071) |
| */ |
| u16_t |
| lwip_standard_chksum(const void *dataptr, int len) |
| { |
| u32_t acc; |
| u16_t src; |
| const u8_t *octetptr; |
| |
| acc = 0; |
| /* dataptr may be at odd or even addresses */ |
| octetptr = (const u8_t *)dataptr; |
| while (len > 1) { |
| /* declare first octet as most significant |
| thus assume network order, ignoring host order */ |
| src = (*octetptr) << 8; |
| octetptr++; |
| /* declare second octet as least significant */ |
| src |= (*octetptr); |
| octetptr++; |
| acc += src; |
| len -= 2; |
| } |
| if (len > 0) { |
| /* accumulate remaining octet */ |
| src = (*octetptr) << 8; |
| acc += src; |
| } |
| /* add deferred carry bits */ |
| acc = (acc >> 16) + (acc & 0x0000ffffUL); |
| if ((acc & 0xffff0000UL) != 0) { |
| acc = (acc >> 16) + (acc & 0x0000ffffUL); |
| } |
| /* This maybe a little confusing: reorder sum using lwip_htons() |
| instead of lwip_ntohs() since it has a little less call overhead. |
| The caller must invert bits for Internet sum ! */ |
| return lwip_htons((u16_t)acc); |
| } |
| #endif |
| |
| #if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */ |
| /* |
| * Curt McDowell |
| * Broadcom Corp. |
| * csm@broadcom.com |
| * |
| * IP checksum two bytes at a time with support for |
| * unaligned buffer. |
| * Works for len up to and including 0x20000. |
| * by Curt McDowell, Broadcom Corp. 12/08/2005 |
| * |
| * @param dataptr points to start of data to be summed at any boundary |
| * @param len length of data to be summed |
| * @return host order (!) lwip checksum (non-inverted Internet sum) |
| */ |
| u16_t |
| lwip_standard_chksum(const void *dataptr, int len) |
| { |
| const u8_t *pb = (const u8_t *)dataptr; |
| const u16_t *ps; |
| u16_t t = 0; |
| u32_t sum = 0; |
| int odd = ((mem_ptr_t)pb & 1); |
| |
| /* Get aligned to u16_t */ |
| if (odd && len > 0) { |
| ((u8_t *)&t)[1] = *pb++; |
| len--; |
| } |
| |
| /* Add the bulk of the data */ |
| ps = (const u16_t *)(const void *)pb; |
| while (len > 1) { |
| sum += *ps++; |
| len -= 2; |
| } |
| |
| /* Consume left-over byte, if any */ |
| if (len > 0) { |
| ((u8_t *)&t)[0] = *(const u8_t *)ps; |
| } |
| |
| /* Add end bytes */ |
| sum += t; |
| |
| /* Fold 32-bit sum to 16 bits |
| calling this twice is probably faster than if statements... */ |
| sum = FOLD_U32T(sum); |
| sum = FOLD_U32T(sum); |
| |
| /* Swap if alignment was odd */ |
| if (odd) { |
| sum = SWAP_BYTES_IN_WORD(sum); |
| } |
| |
| return (u16_t)sum; |
| } |
| #endif |
| |
| #if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */ |
| /** |
| * An optimized checksum routine. Basically, it uses loop-unrolling on |
| * the checksum loop, treating the head and tail bytes specially, whereas |
| * the inner loop acts on 8 bytes at a time. |
| * |
| * @arg start of buffer to be checksummed. May be an odd byte address. |
| * @len number of bytes in the buffer to be checksummed. |
| * @return host order (!) lwip checksum (non-inverted Internet sum) |
| * |
| * by Curt McDowell, Broadcom Corp. December 8th, 2005 |
| */ |
| u16_t |
| lwip_standard_chksum(const void *dataptr, int len) |
| { |
| const u8_t *pb = (const u8_t *)dataptr; |
| const u16_t *ps; |
| u16_t t = 0; |
| const u32_t *pl; |
| u32_t sum = 0, tmp; |
| /* starts at odd byte address? */ |
| int odd = ((mem_ptr_t)pb & 1); |
| |
| if (odd && len > 0) { |
| ((u8_t *)&t)[1] = *pb++; |
| len--; |
| } |
| |
| ps = (const u16_t *)(const void *)pb; |
| |
| if (((mem_ptr_t)ps & 3) && len > 1) { |
| sum += *ps++; |
| len -= 2; |
| } |
| |
| pl = (const u32_t *)(const void *)ps; |
| |
| while (len > 7) { |
| tmp = sum + *pl++; /* ping */ |
| if (tmp < sum) { |
| tmp++; /* add back carry */ |
| } |
| |
| sum = tmp + *pl++; /* pong */ |
| if (sum < tmp) { |
| sum++; /* add back carry */ |
| } |
| |
| len -= 8; |
| } |
| |
| /* make room in upper bits */ |
| sum = FOLD_U32T(sum); |
| |
| ps = (const u16_t *)pl; |
| |
| /* 16-bit aligned word remaining? */ |
| while (len > 1) { |
| sum += *ps++; |
| len -= 2; |
| } |
| |
| /* dangling tail byte remaining? */ |
| if (len > 0) { /* include odd byte */ |
| ((u8_t *)&t)[0] = *(const u8_t *)ps; |
| } |
| |
| sum += t; /* add end bytes */ |
| |
| /* Fold 32-bit sum to 16 bits |
| calling this twice is probably faster than if statements... */ |
| sum = FOLD_U32T(sum); |
| sum = FOLD_U32T(sum); |
| |
| if (odd) { |
| sum = SWAP_BYTES_IN_WORD(sum); |
| } |
| |
| return (u16_t)sum; |
| } |
| #endif |
| |
| /** Parts of the pseudo checksum which are common to IPv4 and IPv6 */ |
| static u16_t |
| inet_cksum_pseudo_base(struct pbuf *p, u8_t proto, u16_t proto_len, u32_t acc) |
| { |
| struct pbuf *q; |
| int swapped = 0; |
| |
| /* iterate through all pbuf in chain */ |
| for (q = p; q != NULL; q = q->next) { |
| LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n", |
| (void *)q, (void *)q->next)); |
| acc += LWIP_CHKSUM(q->payload, q->len); |
| /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/ |
| /* just executing this next line is probably faster that the if statement needed |
| to check whether we really need to execute it, and does no harm */ |
| acc = FOLD_U32T(acc); |
| if (q->len % 2 != 0) { |
| swapped = !swapped; |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/ |
| } |
| |
| if (swapped) { |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| |
| acc += (u32_t)lwip_htons((u16_t)proto); |
| acc += (u32_t)lwip_htons(proto_len); |
| |
| /* Fold 32-bit sum to 16 bits |
| calling this twice is probably faster than if statements... */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc)); |
| return (u16_t)~(acc & 0xffffUL); |
| } |
| |
| #if LWIP_IPV4 |
| /* inet_chksum_pseudo: |
| * |
| * Calculates the IPv4 pseudo Internet checksum used by TCP and UDP for a pbuf chain. |
| * IP addresses are expected to be in network byte order. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param src source ip address (used for checksum of pseudo header) |
| * @param dst destination ip address (used for checksum of pseudo header) |
| * @param proto ip protocol (used for checksum of pseudo header) |
| * @param proto_len length of the ip data part (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| inet_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len, |
| const ip4_addr_t *src, const ip4_addr_t *dest) |
| { |
| u32_t acc; |
| u32_t addr; |
| |
| addr = ip4_addr_get_u32(src); |
| acc = (addr & 0xffffUL); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| addr = ip4_addr_get_u32(dest); |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| /* fold down to 16 bits */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| |
| return inet_cksum_pseudo_base(p, proto, proto_len, acc); |
| } |
| #endif /* LWIP_IPV4 */ |
| |
| #if LWIP_IPV6 |
| /** |
| * Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain. |
| * IPv6 addresses are expected to be in network byte order. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param proto ipv6 protocol/next header (used for checksum of pseudo header) |
| * @param proto_len length of the ipv6 payload (used for checksum of pseudo header) |
| * @param src source ipv6 address (used for checksum of pseudo header) |
| * @param dest destination ipv6 address (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| ip6_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len, |
| const ip6_addr_t *src, const ip6_addr_t *dest) |
| { |
| u32_t acc = 0; |
| u32_t addr; |
| u8_t addr_part; |
| |
| for (addr_part = 0; addr_part < 4; addr_part++) { |
| addr = src->addr[addr_part]; |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| addr = dest->addr[addr_part]; |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| } |
| /* fold down to 16 bits */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| |
| return inet_cksum_pseudo_base(p, proto, proto_len, acc); |
| } |
| #endif /* LWIP_IPV6 */ |
| |
| /* ip_chksum_pseudo: |
| * |
| * Calculates the IPv4 or IPv6 pseudo Internet checksum used by TCP and UDP for a pbuf chain. |
| * IP addresses are expected to be in network byte order. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param src source ip address (used for checksum of pseudo header) |
| * @param dst destination ip address (used for checksum of pseudo header) |
| * @param proto ip protocol (used for checksum of pseudo header) |
| * @param proto_len length of the ip data part (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| ip_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len, |
| const ip_addr_t *src, const ip_addr_t *dest) |
| { |
| #if LWIP_IPV6 |
| if (IP_IS_V6(dest)) { |
| return ip6_chksum_pseudo(p, proto, proto_len, ip_2_ip6(src), ip_2_ip6(dest)); |
| } |
| #endif /* LWIP_IPV6 */ |
| #if LWIP_IPV4 && LWIP_IPV6 |
| else |
| #endif /* LWIP_IPV4 && LWIP_IPV6 */ |
| #if LWIP_IPV4 |
| { |
| return inet_chksum_pseudo(p, proto, proto_len, ip_2_ip4(src), ip_2_ip4(dest)); |
| } |
| #endif /* LWIP_IPV4 */ |
| } |
| |
| /** Parts of the pseudo checksum which are common to IPv4 and IPv6 */ |
| static u16_t |
| inet_cksum_pseudo_partial_base(struct pbuf *p, u8_t proto, u16_t proto_len, |
| u16_t chksum_len, u32_t acc) |
| { |
| struct pbuf *q; |
| int swapped = 0; |
| u16_t chklen; |
| |
| /* iterate through all pbuf in chain */ |
| for (q = p; (q != NULL) && (chksum_len > 0); q = q->next) { |
| LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n", |
| (void *)q, (void *)q->next)); |
| chklen = q->len; |
| if (chklen > chksum_len) { |
| chklen = chksum_len; |
| } |
| acc += LWIP_CHKSUM(q->payload, chklen); |
| chksum_len = (u16_t)(chksum_len - chklen); |
| LWIP_ASSERT("delete me", chksum_len < 0x7fff); |
| /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/ |
| /* fold the upper bit down */ |
| acc = FOLD_U32T(acc); |
| if (q->len % 2 != 0) { |
| swapped = !swapped; |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/ |
| } |
| |
| if (swapped) { |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| |
| acc += (u32_t)lwip_htons((u16_t)proto); |
| acc += (u32_t)lwip_htons(proto_len); |
| |
| /* Fold 32-bit sum to 16 bits |
| calling this twice is probably faster than if statements... */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc)); |
| return (u16_t)~(acc & 0xffffUL); |
| } |
| |
| #if LWIP_IPV4 |
| /* inet_chksum_pseudo_partial: |
| * |
| * Calculates the IPv4 pseudo Internet checksum used by TCP and UDP for a pbuf chain. |
| * IP addresses are expected to be in network byte order. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param src source ip address (used for checksum of pseudo header) |
| * @param dst destination ip address (used for checksum of pseudo header) |
| * @param proto ip protocol (used for checksum of pseudo header) |
| * @param proto_len length of the ip data part (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| inet_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len, |
| u16_t chksum_len, const ip4_addr_t *src, const ip4_addr_t *dest) |
| { |
| u32_t acc; |
| u32_t addr; |
| |
| addr = ip4_addr_get_u32(src); |
| acc = (addr & 0xffffUL); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| addr = ip4_addr_get_u32(dest); |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| /* fold down to 16 bits */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| |
| return inet_cksum_pseudo_partial_base(p, proto, proto_len, chksum_len, acc); |
| } |
| #endif /* LWIP_IPV4 */ |
| |
| #if LWIP_IPV6 |
| /** |
| * Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain. |
| * IPv6 addresses are expected to be in network byte order. Will only compute for a |
| * portion of the payload. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param proto ipv6 protocol/next header (used for checksum of pseudo header) |
| * @param proto_len length of the ipv6 payload (used for checksum of pseudo header) |
| * @param chksum_len number of payload bytes used to compute chksum |
| * @param src source ipv6 address (used for checksum of pseudo header) |
| * @param dest destination ipv6 address (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| ip6_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len, |
| u16_t chksum_len, const ip6_addr_t *src, const ip6_addr_t *dest) |
| { |
| u32_t acc = 0; |
| u32_t addr; |
| u8_t addr_part; |
| |
| for (addr_part = 0; addr_part < 4; addr_part++) { |
| addr = src->addr[addr_part]; |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| addr = dest->addr[addr_part]; |
| acc = (u32_t)(acc + (addr & 0xffffUL)); |
| acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL)); |
| } |
| /* fold down to 16 bits */ |
| acc = FOLD_U32T(acc); |
| acc = FOLD_U32T(acc); |
| |
| return inet_cksum_pseudo_partial_base(p, proto, proto_len, chksum_len, acc); |
| } |
| #endif /* LWIP_IPV6 */ |
| |
| /* ip_chksum_pseudo_partial: |
| * |
| * Calculates the IPv4 or IPv6 pseudo Internet checksum used by TCP and UDP for a pbuf chain. |
| * |
| * @param p chain of pbufs over that a checksum should be calculated (ip data part) |
| * @param src source ip address (used for checksum of pseudo header) |
| * @param dst destination ip address (used for checksum of pseudo header) |
| * @param proto ip protocol (used for checksum of pseudo header) |
| * @param proto_len length of the ip data part (used for checksum of pseudo header) |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| ip_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len, |
| u16_t chksum_len, const ip_addr_t *src, const ip_addr_t *dest) |
| { |
| #if LWIP_IPV6 |
| if (IP_IS_V6(dest)) { |
| return ip6_chksum_pseudo_partial(p, proto, proto_len, chksum_len, ip_2_ip6(src), ip_2_ip6(dest)); |
| } |
| #endif /* LWIP_IPV6 */ |
| #if LWIP_IPV4 && LWIP_IPV6 |
| else |
| #endif /* LWIP_IPV4 && LWIP_IPV6 */ |
| #if LWIP_IPV4 |
| { |
| return inet_chksum_pseudo_partial(p, proto, proto_len, chksum_len, ip_2_ip4(src), ip_2_ip4(dest)); |
| } |
| #endif /* LWIP_IPV4 */ |
| } |
| |
| /* inet_chksum: |
| * |
| * Calculates the Internet checksum over a portion of memory. Used primarily for IP |
| * and ICMP. |
| * |
| * @param dataptr start of the buffer to calculate the checksum (no alignment needed) |
| * @param len length of the buffer to calculate the checksum |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| |
| u16_t |
| inet_chksum(const void *dataptr, u16_t len) |
| { |
| return (u16_t)~(unsigned int)LWIP_CHKSUM(dataptr, len); |
| } |
| |
| /** |
| * Calculate a checksum over a chain of pbufs (without pseudo-header, much like |
| * inet_chksum only pbufs are used). |
| * |
| * @param p pbuf chain over that the checksum should be calculated |
| * @return checksum (as u16_t) to be saved directly in the protocol header |
| */ |
| u16_t |
| inet_chksum_pbuf(struct pbuf *p) |
| { |
| u32_t acc; |
| struct pbuf *q; |
| int swapped = 0; |
| |
| acc = 0; |
| for (q = p; q != NULL; q = q->next) { |
| acc += LWIP_CHKSUM(q->payload, q->len); |
| acc = FOLD_U32T(acc); |
| if (q->len % 2 != 0) { |
| swapped = !swapped; |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| } |
| |
| if (swapped) { |
| acc = SWAP_BYTES_IN_WORD(acc); |
| } |
| return (u16_t)~(acc & 0xffffUL); |
| } |
| |
| /* These are some implementations for LWIP_CHKSUM_COPY, which copies data |
| * like MEMCPY but generates a checksum at the same time. Since this is a |
| * performance-sensitive function, you might want to create your own version |
| * in assembly targeted at your hardware by defining it in lwipopts.h: |
| * #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len) |
| */ |
| |
| #if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */ |
| /** Safe but slow: first call MEMCPY, then call LWIP_CHKSUM. |
| * For architectures with big caches, data might still be in cache when |
| * generating the checksum after copying. |
| */ |
| u16_t |
| lwip_chksum_copy(void *dst, const void *src, u16_t len) |
| { |
| MEMCPY(dst, src, len); |
| return LWIP_CHKSUM(dst, len); |
| } |
| #endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */ |