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net_chksum.c:mod process of generating sum to solve checksum error 

Signed-off-by: wangchen <wangchen41@xiaomi.com>
This commit is contained in:
wangchen 2023-10-18 14:11:44 +08:00 committed by Xiang Xiao
parent 27c2940df2
commit ff7eda46e7
1 changed files with 87 additions and 36 deletions
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121
net/utils/net_chksum.c
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@ -27,6 +27,86 @@
#include "utils/utils.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: checksum
*
* 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.
* odd - the flag of the Calculated data sum
*
* Returned Value:
* The updated checksum value.
*
****************************************************************************/
#ifndef CONFIG_NET_ARCH_CHKSUM
uint16_t checksum(uint16_t sum, FAR const uint8_t *data,
uint16_t len, bool *odd)
{
FAR const uint8_t *dataptr;
FAR const uint8_t *last_byte;
uint16_t t;
dataptr = data;
last_byte = data + len - 1;
if (*odd == true)
{
t = dataptr[0];
sum += t;
if (sum < t)
{
sum++; /* carry */
}
dataptr += 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;
}
*odd = false;
if (dataptr == last_byte)
{
t = (dataptr[0] << 8) + 0;
sum += t;
if (sum < t)
{
sum++; /* carry */
}
*odd = true;
}
/* Return sum in host byte order. */
return sum;
}
/****************************************************************************
* Public Functions
****************************************************************************/
@ -50,44 +130,13 @@
*
****************************************************************************/
#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;
bool odd = false;
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 */
return checksum(sum, data, len, &odd);
}
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 */
/****************************************************************************
@ -113,6 +162,8 @@ uint16_t chksum_iob(uint16_t sum, FAR struct iob_s *iob, uint16_t offset)
{
/* Skip to the I/O buffer containing the data offset */
bool odd = false;
while (iob != NULL && offset > iob->io_len)
{
offset -= iob->io_len;
@ -125,8 +176,8 @@ uint16_t chksum_iob(uint16_t sum, FAR struct iob_s *iob, uint16_t offset)
while (iob != NULL)
{
sum = chksum(sum, iob->io_data + iob->io_offset + offset,
iob->io_len - offset);
sum = checksum(sum, iob->io_data + iob->io_offset + offset,
iob->io_len - offset, &odd);
iob = iob->io_flink;
offset = 0;
}