incubator-nuttx/net/utils/net_incr32.c

123 lines
4.0 KiB
C

/****************************************************************************
* net/utils/net_incr32.c
*
* Copyright (C) 2007-2010, 2012, 2014-2015, 2017 Gregory Nutt. All
* rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/icmp.h>
#include "utils/utils.h"
#ifndef CONFIG_NET_ARCH_INCR32
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: net_carry32
*
* Description:
* Calculate the Internet checksum over a buffer.
*
****************************************************************************/
static inline void net_carry32(FAR uint8_t *sum, uint16_t op16)
{
if (sum[2] < (op16 >> 8))
{
++sum[1];
if (sum[1] == 0)
{
++sum[0];
}
}
if (sum[3] < (op16 & 0xff))
{
++sum[2];
if (sum[2] == 0)
{
++sum[1];
if (sum[1] == 0)
{
++sum[0];
}
}
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: net_incr32
*
* Description:
*
* Carry out a 32-bit addition.
*
* By defining CONFIG_NET_ARCH_INCR32, the architecture can replace
* net_incr32 with hardware assisted solutions.
*
* Input Parameters:
* op32 - A pointer to a 4-byte array representing a 32-bit integer in
* network byte order (big endian). This value may not be word
* aligned. The value pointed to by op32 is modified in place
*
* op16 - A 16-bit integer in host byte order.
*
****************************************************************************/
void net_incr32(FAR uint8_t *op32, uint16_t op16)
{
op32[3] += (op16 & 0xff);
op32[2] += (op16 >> 8);
net_carry32(op32, op16);
}
#endif /* CONFIG_NET_ARCH_INCR32 */