lwip/src/core/ipv6/inet6.c

/**
 * @file
 * Functions common to all TCP/IPv6 modules, such as the Internet checksum and the
 * byte order 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/def.h"
#include "lwip/inet.h"

/* chksum:
 *
 * Sums up all 16 bit words in a memory portion. Also includes any odd byte.
 * This function is used by the other checksum functions.
 *
 * For now, this is not optimized. Must be optimized for the particular processor
 * arcitecture on which it is to run. Preferebly coded in assembler.
 */

static u32_t
chksum(void *dataptr, u16_t len)
{
  u16_t *sdataptr = dataptr;
  u32_t acc;


  for(acc = 0; len > 1; len -= 2) {
    acc += *sdataptr++;
  }

  /* add up any odd byte */
  if (len == 1) {
    acc += htons((u16_t)(*(u8_t *)dataptr) << 8);
  }

  return acc;

}

/* inet_chksum_pseudo:
 *
 * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
 */

u16_t
inet_chksum_pseudo(struct pbuf *p,
       struct ip_addr *src, struct ip_addr *dest,
       u8_t proto, u32_t proto_len)
{
  u32_t acc;
  struct pbuf *q;
  u8_t swapped, i;

  acc = 0;
  swapped = 0;
  for(q = p; q != NULL; q = q->next) {
    acc += chksum(q->payload, q->len);
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
    if (q->len % 2 != 0) {
      swapped = 1 - swapped;
      acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
    }
  }

  if (swapped) {
    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
  }

  for(i = 0; i < 8; i++) {
    acc += ((u16_t *)src->addr)[i] & 0xffff;
    acc += ((u16_t *)dest->addr)[i] & 0xffff;
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
  }
  acc += (u16_t)htons((u16_t)proto);
  acc += ((u16_t *)&proto_len)[0] & 0xffff;
  acc += ((u16_t *)&proto_len)[1] & 0xffff;

  while (acc >> 16) {
    acc = (acc & 0xffff) + (acc >> 16);
  }
  return ~(acc & 0xffff);
}

/* inet_chksum:
 *
 * Calculates the Internet checksum over a portion of memory. Used primarely for IP
 * and ICMP.
 */

u16_t
inet_chksum(void *dataptr, u16_t len)
{
  u32_t acc, sum;

  acc = chksum(dataptr, len);
  sum = (acc & 0xffff) + (acc >> 16);
  sum += (sum >> 16);
  return ~(sum & 0xffff);
}

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 += chksum(q->payload, q->len);
    while (acc >> 16) {
      acc = (acc & 0xffff) + (acc >> 16);
    }
    if (q->len % 2 != 0) {
      swapped = 1 - swapped;
      acc = (acc & 0xff << 8) | (acc & 0xff00 >> 8);
    }
  }

  if (swapped) {
    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
  }
  return ~(acc & 0xffff);
}
Commit	Line	Data
	1	/**
	2	* @file
	3	* Functions common to all TCP/IPv6 modules, such as the Internet checksum and the
	4	* byte order functions.
	5	*
	6	*/
	7
	8	/*
	9	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
	10	* All rights reserved.
	11	*
	12	* Redistribution and use in source and binary forms, with or without modification,
	13	* are permitted provided that the following conditions are met:
	14	*
	15	* 1. Redistributions of source code must retain the above copyright notice,
	16	* this list of conditions and the following disclaimer.
	17	* 2. Redistributions in binary form must reproduce the above copyright notice,
	18	* this list of conditions and the following disclaimer in the documentation
	19	* and/or other materials provided with the distribution.
	20	* 3. The name of the author may not be used to endorse or promote products
	21	* derived from this software without specific prior written permission.
	22	*
	23	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	24	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	25	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
	26	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	27	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	28	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	29	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	30	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	31	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
	32	* OF SUCH DAMAGE.
	33	*
	34	* This file is part of the lwIP TCP/IP stack.
	35	*
	36	* Author: Adam Dunkels <adam@sics.se>
	37	*
	38	*/
	39
	40	#include "lwip/opt.h"
	41
	42	#include "lwip/def.h"
	43	#include "lwip/inet.h"
	44
	45	/* chksum:
	46	*
	47	* Sums up all 16 bit words in a memory portion. Also includes any odd byte.
	48	* This function is used by the other checksum functions.
	49	*
	50	* For now, this is not optimized. Must be optimized for the particular processor
	51	* arcitecture on which it is to run. Preferebly coded in assembler.
	52	*/
	53
	54	static u32_t
	55	chksum(void *dataptr, u16_t len)
	56	{
	57	u16_t *sdataptr = dataptr;
	58	u32_t acc;
	59
	60
	61	for(acc = 0; len > 1; len -= 2) {
	62	acc += *sdataptr++;
	63	}
	64
	65	/* add up any odd byte */
	66	if (len == 1) {
	67	acc += htons((u16_t)((u8_t )dataptr) << 8);
	68	}
	69
	70	return acc;
	71
	72	}
	73
	74	/* inet_chksum_pseudo:
	75	*
	76	* Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
	77	*/
	78
	79	u16_t
	80	inet_chksum_pseudo(struct pbuf *p,
	81	struct ip_addr src, struct ip_addr dest,
	82	u8_t proto, u32_t proto_len)
	83	{
	84	u32_t acc;
	85	struct pbuf *q;
	86	u8_t swapped, i;
	87
	88	acc = 0;
	89	swapped = 0;
	90	for(q = p; q != NULL; q = q->next) {
	91	acc += chksum(q->payload, q->len);
	92	while (acc >> 16) {
	93	acc = (acc & 0xffff) + (acc >> 16);
	94	}
	95	if (q->len % 2 != 0) {
	96	swapped = 1 - swapped;
	97	acc = ((acc & 0xff) << 8) \| ((acc & 0xff00) >> 8);
	98	}
	99	}
	100
	101	if (swapped) {
	102	acc = ((acc & 0xff) << 8) \| ((acc & 0xff00) >> 8);
	103	}
	104
	105	for(i = 0; i < 8; i++) {
	106	acc += ((u16_t *)src->addr)[i] & 0xffff;
	107	acc += ((u16_t *)dest->addr)[i] & 0xffff;
	108	while (acc >> 16) {
	109	acc = (acc & 0xffff) + (acc >> 16);
	110	}
	111	}
	112	acc += (u16_t)htons((u16_t)proto);
	113	acc += ((u16_t *)&proto_len)[0] & 0xffff;
	114	acc += ((u16_t *)&proto_len)[1] & 0xffff;
	115
	116	while (acc >> 16) {
	117	acc = (acc & 0xffff) + (acc >> 16);
	118	}
	119	return ~(acc & 0xffff);
	120	}
	121
	122	/* inet_chksum:
	123	*
	124	* Calculates the Internet checksum over a portion of memory. Used primarely for IP
	125	* and ICMP.
	126	*/
	127
	128	u16_t
	129	inet_chksum(void *dataptr, u16_t len)
	130	{
	131	u32_t acc, sum;
	132
	133	acc = chksum(dataptr, len);
	134	sum = (acc & 0xffff) + (acc >> 16);
	135	sum += (sum >> 16);
	136	return ~(sum & 0xffff);
	137	}
	138
	139	u16_t
	140	inet_chksum_pbuf(struct pbuf *p)
	141	{
	142	u32_t acc;
	143	struct pbuf *q;
	144	u8_t swapped;
	145
	146	acc = 0;
	147	swapped = 0;
	148	for(q = p; q != NULL; q = q->next) {
	149	acc += chksum(q->payload, q->len);
	150	while (acc >> 16) {
	151	acc = (acc & 0xffff) + (acc >> 16);
	152	}
	153	if (q->len % 2 != 0) {
	154	swapped = 1 - swapped;
	155	acc = (acc & 0xff << 8) \| (acc & 0xff00 >> 8);
	156	}
	157	}
	158
	159	if (swapped) {
	160	acc = ((acc & 0xff) << 8) \| ((acc & 0xff00) >> 8);
	161	}
	162	return ~(acc & 0xffff);
	163	}