Diff: lwip/core/ipv4/inet_chksum.c

Revision:

1:9d93f4dc2f46

Parent:

0:8b387bed54c2

--- a/lwip/core/ipv4/inet_chksum.c	Mon Jan 10 21:03:11 2011 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,450 +0,0 @@
-/**
- * @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) */