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109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/**
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* @file
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* Common functions used throughout the stack.
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*
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*/
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/*
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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Simon Goldschmidt
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*
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*/
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#include "lwip/opt.h"
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#include "lwip/def.h"
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/**
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* These are reference implementations of the byte swapping functions.
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* Again with the aim of being simple, correct and fully portable.
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* Byte swapping is the second thing you would want to optimize. You will
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* need to port it to your architecture and in your cc.h:
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*
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* #define LWIP_PLATFORM_BYTESWAP 1
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* #define LWIP_PLATFORM_HTONS(x) <your_htons>
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* #define LWIP_PLATFORM_HTONL(x) <your_htonl>
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*
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* Note ntohs() and ntohl() are merely references to the htonx counterparts.
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*/
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#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
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/**
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* Convert an u16_t from host- to network byte order.
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*
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* @param n u16_t in host byte order
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* @return n in network byte order
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*/
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u16_t
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lwip_htons(u16_t n)
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{
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return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
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}
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/**
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* Convert an u16_t from network- to host byte order.
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*
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* @param n u16_t in network byte order
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* @return n in host byte order
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*/
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u16_t
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lwip_ntohs(u16_t n)
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{
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return lwip_htons(n);
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}
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/**
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* Convert an u32_t from host- to network byte order.
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*
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* @param n u32_t in host byte order
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* @return n in network byte order
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*/
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u32_t
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lwip_htonl(u32_t n)
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{
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return ((n & 0xff) << 24) |
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((n & 0xff00) << 8) |
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((n & 0xff0000UL) >> 8) |
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((n & 0xff000000UL) >> 24);
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}
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/**
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* Convert an u32_t from network- to host byte order.
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*
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* @param n u32_t in network byte order
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* @return n in host byte order
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*/
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u32_t
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lwip_ntohl(u32_t n)
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{
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return lwip_htonl(n);
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}
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#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */
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