127 lines
3.7 KiB
C
127 lines
3.7 KiB
C
/****************************************************************************
|
|
* net/utils/net_chksum.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
#ifdef CONFIG_NET
|
|
|
|
#include "utils/utils.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: chksum
|
|
*
|
|
* Description:
|
|
* Calculate the raw change sum over the memory region described by
|
|
* data and len.
|
|
*
|
|
* Input Parameters:
|
|
* sum - Partial calculations carried over from a previous call to
|
|
* chksum(). This should be zero on the first time that check
|
|
* sum is called.
|
|
* data - Beginning of the data to include in the checksum.
|
|
* len - Length of the data to include in the checksum.
|
|
*
|
|
* Returned Value:
|
|
* The updated checksum value.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifndef CONFIG_NET_ARCH_CHKSUM
|
|
uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
|
|
{
|
|
FAR const uint8_t *dataptr;
|
|
FAR const uint8_t *last_byte;
|
|
uint16_t t;
|
|
|
|
dataptr = data;
|
|
last_byte = data + len - 1;
|
|
|
|
while (dataptr < last_byte)
|
|
{
|
|
/* At least two more bytes */
|
|
|
|
t = ((uint16_t)dataptr[0] << 8) + dataptr[1];
|
|
sum += t;
|
|
if (sum < t)
|
|
{
|
|
sum++; /* carry */
|
|
}
|
|
|
|
dataptr += 2;
|
|
}
|
|
|
|
if (dataptr == last_byte)
|
|
{
|
|
t = (dataptr[0] << 8) + 0;
|
|
sum += t;
|
|
if (sum < t)
|
|
{
|
|
sum++; /* carry */
|
|
}
|
|
}
|
|
|
|
/* Return sum in host byte order. */
|
|
|
|
return sum;
|
|
}
|
|
#endif /* CONFIG_NET_ARCH_CHKSUM */
|
|
|
|
/****************************************************************************
|
|
* Name: net_chksum
|
|
*
|
|
* Description:
|
|
* Calculate the Internet checksum over a buffer.
|
|
*
|
|
* The Internet checksum is the one's complement of the one's complement
|
|
* sum of all 16-bit words in the buffer.
|
|
*
|
|
* See RFC1071.
|
|
*
|
|
* If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
|
|
* provided by architecture-specific logic.
|
|
*
|
|
* Input Parameters:
|
|
*
|
|
* buf - A pointer to the buffer over which the checksum is to be computed.
|
|
*
|
|
* len - The length of the buffer over which the checksum is to be
|
|
* computed.
|
|
*
|
|
* Returned Value:
|
|
* The Internet checksum of the buffer.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifndef CONFIG_NET_ARCH_CHKSUM
|
|
uint16_t net_chksum(FAR uint16_t *data, uint16_t len)
|
|
{
|
|
return HTONS(chksum(0, (uint8_t *)data, len));
|
|
}
|
|
#endif /* CONFIG_NET_ARCH_CHKSUM */
|
|
|
|
#endif /* CONFIG_NET */
|