Copy of NetServicesMin with the HTTP Client library. Includes modification for HTTP servers which send the HTTP status line in its own packet.
lwip/core/ipv4/inet_chksum.c
- Committer:
- andrewbonney
- Date:
- 2011-05-26
- Revision:
- 0:18dd877d2c77
File content as of revision 0:18dd877d2c77:
/** * @file * Incluse internet checksum functions. * */ /* * 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 <stddef.h> #include <string.h> /* 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. */ #ifndef LWIP_CHKSUM # define LWIP_CHKSUM lwip_standard_chksum # ifndef LWIP_CHKSUM_ALGORITHM # define LWIP_CHKSUM_ALGORITHM 2 # endif #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) */ static u16_t lwip_standard_chksum(void *dataptr, u16_t len) { u32_t acc; u16_t src; u8_t *octetptr; acc = 0; /* dataptr may be at odd or even addresses */ octetptr = (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 htons() instead of ntohs() since it has a little less call overhead. The caller must invert bits for Internet sum ! */ return 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) */ static u16_t lwip_standard_chksum(void *dataptr, int len) { u8_t *pb = (u8_t *)dataptr; u16_t *ps, 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 = (u16_t *)(void *)pb; while (len > 1) { sum += *ps++; len -= 2; } /* Consume left-over byte, if any */ if (len > 0) { ((u8_t *)&t)[0] = *(u8_t *)ps; } /* Add end bytes */ sum += t; /* Fold 32-bit sum to 16 bits calling this twice is propably 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 */ static u16_t lwip_standard_chksum(void *dataptr, int len) { u8_t *pb = (u8_t *)dataptr; u16_t *ps, t = 0; 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 = (u16_t *)pb; if (((mem_ptr_t)ps & 3) && len > 1) { sum += *ps++; len -= 2; } pl = (u32_t *)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 = (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] = *(u8_t *)ps; } sum += t; /* add end bytes */ /* Fold 32-bit sum to 16 bits calling this twice is propably 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 /* inet_chksum_pseudo: * * Calculates the 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, ip_addr_t *src, ip_addr_t *dest, u8_t proto, u16_t proto_len) { u32_t acc; u32_t addr; struct pbuf *q; u8_t swapped; acc = 0; 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 = 1 - 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); } addr = ip4_addr_get_u32(src); acc += (addr & 0xffffUL); acc += ((addr >> 16) & 0xffffUL); addr = ip4_addr_get_u32(dest); acc += (addr & 0xffffUL); acc += ((addr >> 16) & 0xffffUL); acc += (u32_t)htons((u16_t)proto); acc += (u32_t)htons(proto_len); /* Fold 32-bit sum to 16 bits calling this twice is propably 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); } /* inet_chksum_pseudo: * * Calculates the 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, ip_addr_t *src, ip_addr_t *dest, u8_t proto, u16_t proto_len, u16_t chksum_len) { u32_t acc; u32_t addr; struct pbuf *q; u8_t swapped; u16_t chklen; acc = 0; swapped = 0; /* 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 -= 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 = 1 - 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); } addr = ip4_addr_get_u32(src); acc += (addr & 0xffffUL); acc += ((addr >> 16) & 0xffffUL); addr = ip4_addr_get_u32(dest); acc += (addr & 0xffffUL); acc += ((addr >> 16) & 0xffffUL); acc += (u32_t)htons((u16_t)proto); acc += (u32_t)htons(proto_len); /* Fold 32-bit sum to 16 bits calling this twice is propably 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); } /* 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(void *dataptr, u16_t len) { return ~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; u8_t swapped; acc = 0; swapped = 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 = 1 - 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) */