www.pudn.com > TCPmodbushy.rar > inet.c
/*
* 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
*
*/
/* inet.c
*
* Functions common to all TCP/IP modules, such as the Internet checksum and the
* byte order functions.
*
*/
#include "o:/lwip/opt.h"
#include "o:/lwip/arch.h"
#include "o:/lwip/def.h"
#include "o:/IPv4/lwip/inet.h"
#include "o:/lwip/sys.h"
#include "o:/lwip/debug.h"
/* This is a reference implementation 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. You will
* need to port it to your architecture and in your sys_arch.h:
*
* #define LWIP_CHKSUM
*/
#ifndef LWIP_CHKSUM
#define LWIP_CHKSUM lwip_standard_chksum
/**
* 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 lenght to 64k
* @note host endianess is irrelevant (p3 RFC1071)
*/
static u16_t
lwip_standard_chksum(void xdata *dataptr, u16_t len)
{
u32_t acc;
u16_t src;
u8_t xdata *octetptr;
acc = 0;
/* dataptr may be at odd or even addresses */
octetptr = (u8_t xdata *)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 & 0xffff0000) != 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 0
/*
* 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
*/
static u16_t
lwip_standard_chksum2(void xdata *dataptr, int len)
{
u8_t xdata *pb = dataptr;
u16_t xdata *ps, t = 0;
u32_t sum = 0;
int odd = ((u32_t)pb & 1);
/* Get aligned to u16_t */
if (odd && len > 0) {
((u8_t xdata *)&t)[1] = *pb++;
len--;
}
/* Add the bulk of the data */
ps = (u16_t xdata *)pb;
while (len > 1) {
sum += *ps++;
len -= 2;
}
/* Consume left-over byte, if any */
if (len > 0)
((u8_t xdata *)&t)[0] = *(u8_t xdata *)ps;;
/* Add end bytes */
sum += t;
/* Fold 32-bit sum to 16 bits */
while (sum >> 16)
sum = (sum & 0xffff) + (sum >> 16);
/* Swap if alignment was odd */
if (odd)
sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
return sum;
}
/**
* 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.
*
* @todo First argument type conflicts with generic checksum routine.
*
* by Curt McDowell, Broadcom Corp. December 8th, 2005
*/
static u16_t
lwip_standard_chksum4(u8_t xdata *pb, int len)
{
u16_t xdata *ps;
u16_t t = 0;
u32_t xdata *pl;
u32_t sum = 0, tmp;
/* starts at odd byte address? */
int odd = ((u32_t)pb & 1);
if (odd && len > 0) {
((u8_t xdata *)&t)[1] = *pb++;
len--;
}
ps = (u16_t xdata *)pb;
if (((u32_t)ps & 3) && len > 1) {
sum += *ps++;
len -= 2;
}
pl = (u32_t xdata *)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 = (sum >> 16) + (sum & 0xffff);
ps = (u16_t xdata *)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 xdata *)&t)[0] = *(u8_t xdata *)ps;
sum += t; /* add end bytes */
while (sum >> 16) /* combine halves */
sum = (sum >> 16) + (sum & 0xffff);
if (odd)
sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);
return sum;
}
#endif
/* inet_chksum_pseudo:
*
* Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
*/
u16_t
inet_chksum_pseudo(struct pbuf xdata *p,
struct ip_addr xdata *src, struct ip_addr xdata *dest,
u8_t proto, u16_t proto_len)
{
u32_t acc;
struct pbuf xdata *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 xdata *)q, (void xdata *)q->next));
acc += LWIP_CHKSUM(q->payload, q->len);
/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
while (acc >> 16) {
acc = (acc & 0xffffUL) + (acc >> 16);
}
if (q->len % 2 != 0) {
swapped = 1 - swapped;
acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
}
/*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
}
if (swapped) {
acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);
}
acc += (src->addr & 0xffffUL);
acc += ((src->addr >> 16) & 0xffffUL);
acc += (dest->addr & 0xffffUL);
acc += ((dest->addr >> 16) & 0xffffUL);
acc += (u32_t)htons((u16_t)proto);
acc += (u32_t)htons(proto_len);
while (acc >> 16) {
acc = (acc & 0xffffUL) + (acc >> 16);
}
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 primarely for IP
* and ICMP.
*/
u16_t
inet_chksum(void xdata *dataptr, u16_t len)
{
u32_t acc;
acc = LWIP_CHKSUM(dataptr, len);
while (acc >> 16) {
acc = (acc & 0xffff) + (acc >> 16);
}
return (u16_t)~(acc & 0xffff);
}
u16_t
inet_chksum_pbuf(struct pbuf xdata *p)
{
u32_t acc;
struct pbuf xdata *q;
u8_t swapped;
acc = 0;
swapped = 0;
for(q = p; q != NULL; q = q->next) {
acc += LWIP_CHKSUM(q->payload, q->len);
while (acc >> 16) {
acc = (acc & 0xffffUL) + (acc >> 16);
}
if (q->len % 2 != 0) {
swapped = 1 - swapped;
acc = (acc & 0x00ffUL << 8) | (acc & 0xff00UL >> 8);
}
}
if (swapped) {
acc = ((acc & 0x00ffUL) << 8) | ((acc & 0xff00UL) >> 8);
}
return (u16_t)~(acc & 0xffffUL);
}
/* Here for now until needed in other places in lwIP */
#ifndef isascii
#define in_range(c, lo, up) ((u8_t)c >= lo && (u8_t)c <= up)
#define isascii(c) in_range(c, 0x20, 0x7f)
#define isdigit(c) in_range(c, '0', '9')
#define isxdigit(c) (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
#define islower(c) in_range(c, 'a', 'z')
#define isspace(c) (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
#endif
#ifndef BYTE_ORDER
#error BYTE_ORDER is not defined
#endif
#if BYTE_ORDER == LITTLE_ENDIAN
u16_t
htons(u16_t n)
{
return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
}
u16_t
ntohs(u16_t n)
{
return htons(n);
}
u32_t
htonl(u32_t n)
{
return ((n & 0xff) << 24) |
((n & 0xff00) << 8) |
((n & 0xff0000) >> 8) |
((n & 0xff000000) >> 24);
}
u32_t
ntohl(u32_t n)
{
return htonl(n);
}
#endif /* BYTE_ORDER == LITTLE_ENDIAN */