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/****************************************************************************
* net/utils/net_chksum.c
*
* Copyright (C) 2007-2010, 2012, 2014 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>
#ifdef CONFIG_NET
#include <stdint.h>
#include <debug.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/icmp.h>
#include "utils/utils.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define BUF ((struct net_iphdr_s *)&dev->d_buf[NET_LLH_LEN])
#define ICMPBUF ((struct icmp_iphdr_s *)&dev->d_buf[NET_LLH_LEN])
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: chksum
****************************************************************************/
#if !CONFIG_NET_ARCH_CHKSUM
static uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len)
{
uint16_t t;
const uint8_t *dataptr;
const uint8_t *last_byte;
dataptr = data;
last_byte = data + len - 1;
while (dataptr < last_byte)
{
/* At least two more bytes */
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: upper_layer_chksum
****************************************************************************/
#if !CONFIG_NET_ARCH_CHKSUM
static uint16_t upper_layer_chksum(FAR struct net_driver_s *dev, uint8_t proto)
{
FAR struct net_iphdr_s *pbuf = BUF;
uint16_t upper_layer_len;
uint16_t sum;
#ifdef CONFIG_NET_IPv6
upper_layer_len = (((uint16_t)(pbuf->len[0]) << 8) + pbuf->len[1]);
#else /* CONFIG_NET_IPv6 */
upper_layer_len = (((uint16_t)(pbuf->len[0]) << 8) + pbuf->len[1]) - IPHDR_LEN;
#endif /* CONFIG_NET_IPv6 */
/* Verify some minimal assumptions */
if (upper_layer_len > CONFIG_NET_BUFSIZE)
{
return 0;
}
/* First sum pseudo-header. */
/* IP protocol and length fields. This addition cannot carry. */
sum = upper_layer_len + proto;
/* Sum IP source and destination addresses. */
sum = chksum(sum, (uint8_t *)&pbuf->srcipaddr, 2 * sizeof(net_ipaddr_t));
/* Sum TCP header and data. */
sum = chksum(sum, &dev->d_buf[IPHDR_LEN + NET_LLH_LEN], upper_layer_len);
return (sum == 0) ? 0xffff : htons(sum);
}
#endif /* CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: icmp_6chksum
****************************************************************************/
#if !CONFIG_NET_ARCH_CHKSUM
#ifdef CONFIG_NET_IPv6
static uint16_t icmp_6chksum(FAR struct net_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_ICMP6);
}
#endif /* CONFIG_NET_IPv6 */
#endif /* CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: net_carry32
*
* Description:
* Calculate the Internet checksum over a buffer.
*
****************************************************************************/
#if !CONFIG_NET_ARCH_INCR32
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];
}
}
}
}
#endif /* CONFIG_NET_ARCH_INCR32 */
/****************************************************************************
* 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.
*
****************************************************************************/
#if !CONFIG_NET_ARCH_INCR32
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 */
/****************************************************************************
* 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.
*
****************************************************************************/
#if !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 */
/****************************************************************************
* Name: ip_chksum
*
* Description:
* Calculate the IP header checksum of the packet header in d_buf.
*
* The IP header checksum is the Internet checksum of the 20 bytes of
* the IP header.
*
* If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
* provided by architecture-specific logic.
*
* Returned Value:
* The IP header checksum of the IP header in the d_buf buffer.
*
****************************************************************************/
#if !CONFIG_NET_ARCH_CHKSUM
uint16_t ip_chksum(FAR struct net_driver_s *dev)
{
uint16_t sum;
sum = chksum(0, &dev->d_buf[NET_LLH_LEN], IPHDR_LEN);
return (sum == 0) ? 0xffff : htons(sum);
}
#endif /* CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: tcp_chksum
*
* Description:
* Calculate the TCP checksum of the packet in d_buf and d_appdata.
*
* The TCP checksum is the Internet checksum of data contents of the
* TCP segment, and a pseudo-header as defined in RFC793.
*
* Note: The d_appdata pointer that points to the packet data may
* point anywhere in memory, so it is not possible to simply calculate
* the Internet checksum of the contents of the d_buf buffer.
*
* Returned Value:
* The TCP checksum of the TCP segment in d_buf and pointed to by
* d_appdata.
*
****************************************************************************/
#if !CONFIG_NET_ARCH_CHKSUM
uint16_t tcp_chksum(FAR struct net_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_TCP);
}
#endif /* CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: udp_chksum
*
* Description:
* Calculate the UDP checksum of the packet in d_buf and d_appdata.
*
****************************************************************************/
#if defined(CONFIG_NET_UDP_CHECKSUMS) && !defined(CONFIG_NET_ARCH_CHKSUM)
uint16_t udp_chksum(FAR struct net_driver_s *dev)
{
return upper_layer_chksum(dev, UIP_PROTO_UDP);
}
#endif /* CONFIG_NET_UDP_CHECKSUMS && !CONFIG_NET_ARCH_CHKSUM */
/****************************************************************************
* Name: icmp_chksum
*
* Description:
* Calculate the checksum of the ICMP message
*
****************************************************************************/
#if defined(CONFIG_NET_ICMP) && defined(CONFIG_NET_ICMP_PING)
uint16_t icmp_chksum(FAR struct net_driver_s *dev, int len)
{
FAR struct icmp_iphdr_s *picmp = ICMPBUF;
return net_chksum((uint16_t*)&picmp->type, len);
}
#endif /* CONFIG_NET_ICMP && CONFIG_NET_ICMP_PING */
#endif /* CONFIG_NET */
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