155 lines
4.9 KiB
C
155 lines
4.9 KiB
C
/****************************************************************************
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* net/utils/net_chksum.c
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*
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* Copyright (C) 2007-2010, 2012, 2014-2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#ifdef CONFIG_NET
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#include <stdint.h>
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#include <debug.h>
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#include <nuttx/net/netconfig.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/ip.h>
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#include <nuttx/net/icmp.h>
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#include "utils/utils.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define IPv4BUF ((struct ipv4_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
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#define IPv6BUF ((struct ipv6_hdr_s *)&dev->d_buf[NET_LL_HDRLEN(dev)])
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: chksum
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*
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* Description:
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* Calculate the raw change some over the memory region described by
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* data and len.
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*
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* Input Parameters:
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* sum - Partial calculations carried over from a previous call to chksum().
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* This should be zero on the first time that check sum is called.
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* data - Beginning of the data to include in the checksum.
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* len - Length of the data to include in the checksum.
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*
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* Returned Value:
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* The updated checksum value.
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*
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****************************************************************************/
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#ifndef CONFIG_NET_ARCH_CHKSUM
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uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
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{
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FAR const uint8_t *dataptr;
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FAR const uint8_t *last_byte;
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uint16_t t;
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dataptr = data;
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last_byte = data + len - 1;
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while (dataptr < last_byte)
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{
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/* At least two more bytes */
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t = ((uint16_t)dataptr[0] << 8) + dataptr[1];
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sum += t;
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if (sum < t)
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{
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sum++; /* carry */
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}
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dataptr += 2;
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}
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if (dataptr == last_byte)
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{
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t = (dataptr[0] << 8) + 0;
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sum += t;
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if (sum < t)
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{
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sum++; /* carry */
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}
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}
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/* Return sum in host byte order. */
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return sum;
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}
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#endif /* CONFIG_NET_ARCH_CHKSUM */
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/****************************************************************************
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* Name: net_chksum
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*
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* Description:
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* Calculate the Internet checksum over a buffer.
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*
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* The Internet checksum is the one's complement of the one's complement
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* sum of all 16-bit words in the buffer.
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*
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* See RFC1071.
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*
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* If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
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* provided by architecture-specific logic.
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*
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* Input Parameters:
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*
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* buf - A pointer to the buffer over which the checksum is to be computed.
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*
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* len - The length of the buffer over which the checksum is to be computed.
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*
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* Returned Value:
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* The Internet checksum of the buffer.
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*
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****************************************************************************/
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#ifndef CONFIG_NET_ARCH_CHKSUM
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uint16_t net_chksum(FAR uint16_t *data, uint16_t len)
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{
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return htons(chksum(0, (uint8_t *)data, len));
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}
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#endif /* CONFIG_NET_ARCH_CHKSUM */
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#endif /* CONFIG_NET */
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