/**************************************************************************** * net/utils/net_chksum.c * * Copyright (C) 2007-2010, 2012, 2014 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #ifdef CONFIG_NET #include #include #include #include #include #include #include "utils/utils.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define BUF ((struct net_iphdr_s *)&dev->d_buf[NET_LL_HDRLEN]) #define ICMPBUF ((struct icmp_iphdr_s *)&dev->d_buf[NET_LL_HDRLEN]) /**************************************************************************** * 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]) - IP_HDRLEN; #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[IP_HDRLEN + NET_LL_HDRLEN], 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, IP_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_LL_HDRLEN], IP_HDRLEN); 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, IP_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, IP_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 */