cassyarduino cassyarduino / UIPEthernet

UIPEthernet library for Arduino IDE, Eclipse with arduino plugin and MBED/SMeshStudio (AVR,STM32F,ESP8266,Intel ARC32,Nordic nRF51,Teensy boards,Realtek Ameba(RTL8195A,RTL8710)), ENC28j60 network chip. Compatible with Wiznet W5100 Ethernet library API. Compiled and tested on Nucleo-F302R8. Master repository is: https://github.com/UIPEthernet/UIPEthernet/

utility/uip_arp.c@39:deeb00b81cc9, 2018-01-23 (annotated)

Committer:
cassyarduino
Date:
Tue Jan 23 15:08:43 2018 +0100
Revision:
39:deeb00b81cc9
Parent:
0:e3fb1267e3c3 
Release: 2.0.4

Who changed what in which revision?

UserRevisionLine numberNew contents of line
cassyarduino 0:e3fb1267e3c3 1 /**
cassyarduino 0:e3fb1267e3c3 2 * \addtogroup uip
cassyarduino 0:e3fb1267e3c3 3 * @{
cassyarduino 0:e3fb1267e3c3 4 */
cassyarduino 0:e3fb1267e3c3 5
cassyarduino 0:e3fb1267e3c3 6 /**
cassyarduino 0:e3fb1267e3c3 7 * \defgroup uiparp uIP Address Resolution Protocol
cassyarduino 0:e3fb1267e3c3 8 * @{
cassyarduino 0:e3fb1267e3c3 9 *
cassyarduino 0:e3fb1267e3c3 10 * The Address Resolution Protocol ARP is used for mapping between IP
cassyarduino 0:e3fb1267e3c3 11 * addresses and link level addresses such as the Ethernet MAC
cassyarduino 0:e3fb1267e3c3 12 * addresses. ARP uses broadcast queries to ask for the link level
cassyarduino 0:e3fb1267e3c3 13 * address of a known IP address and the host which is configured with
cassyarduino 0:e3fb1267e3c3 14 * the IP address for which the query was meant, will respond with its
cassyarduino 0:e3fb1267e3c3 15 * link level address.
cassyarduino 0:e3fb1267e3c3 16 *
cassyarduino 0:e3fb1267e3c3 17 * \note This ARP implementation only supports Ethernet.
cassyarduino 0:e3fb1267e3c3 18 */
cassyarduino 0:e3fb1267e3c3 19
cassyarduino 0:e3fb1267e3c3 20 /**
cassyarduino 0:e3fb1267e3c3 21 * \file
cassyarduino 0:e3fb1267e3c3 22 * Implementation of the ARP Address Resolution Protocol.
cassyarduino 0:e3fb1267e3c3 23 * \author Adam Dunkels <adam@dunkels.com>
cassyarduino 0:e3fb1267e3c3 24 *
cassyarduino 0:e3fb1267e3c3 25 */
cassyarduino 0:e3fb1267e3c3 26
cassyarduino 0:e3fb1267e3c3 27 /*
cassyarduino 0:e3fb1267e3c3 28 * Copyright (c) 2001-2003, Adam Dunkels.
cassyarduino 0:e3fb1267e3c3 29 * All rights reserved.
cassyarduino 0:e3fb1267e3c3 30 *
cassyarduino 0:e3fb1267e3c3 31 * Redistribution and use in source and binary forms, with or without
cassyarduino 0:e3fb1267e3c3 32 * modification, are permitted provided that the following conditions
cassyarduino 0:e3fb1267e3c3 33 * are met:
cassyarduino 0:e3fb1267e3c3 34 * 1. Redistributions of source code must retain the above copyright
cassyarduino 0:e3fb1267e3c3 35 * notice, this list of conditions and the following disclaimer.
cassyarduino 0:e3fb1267e3c3 36 * 2. Redistributions in binary form must reproduce the above copyright
cassyarduino 0:e3fb1267e3c3 37 * notice, this list of conditions and the following disclaimer in the
cassyarduino 0:e3fb1267e3c3 38 * documentation and/or other materials provided with the distribution.
cassyarduino 0:e3fb1267e3c3 39 * 3. The name of the author may not be used to endorse or promote
cassyarduino 0:e3fb1267e3c3 40 * products derived from this software without specific prior
cassyarduino 0:e3fb1267e3c3 41 * written permission.
cassyarduino 0:e3fb1267e3c3 42 *
cassyarduino 0:e3fb1267e3c3 43 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
cassyarduino 0:e3fb1267e3c3 44 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
cassyarduino 0:e3fb1267e3c3 45 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
cassyarduino 0:e3fb1267e3c3 46 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
cassyarduino 0:e3fb1267e3c3 47 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
cassyarduino 0:e3fb1267e3c3 48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
cassyarduino 0:e3fb1267e3c3 49 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
cassyarduino 0:e3fb1267e3c3 50 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
cassyarduino 0:e3fb1267e3c3 51 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
cassyarduino 0:e3fb1267e3c3 52 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
cassyarduino 0:e3fb1267e3c3 53 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
cassyarduino 0:e3fb1267e3c3 54 *
cassyarduino 0:e3fb1267e3c3 55 * This file is part of the uIP TCP/IP stack.
cassyarduino 0:e3fb1267e3c3 56 *
cassyarduino 0:e3fb1267e3c3 57 * $Id: uip_arp.c,v 1.8 2006/06/02 23:36:21 adam Exp $
cassyarduino 0:e3fb1267e3c3 58 *
cassyarduino 0:e3fb1267e3c3 59 */
cassyarduino 0:e3fb1267e3c3 60
cassyarduino 0:e3fb1267e3c3 61
cassyarduino 0:e3fb1267e3c3 62 #include "uip_arp.h"
cassyarduino 0:e3fb1267e3c3 63
cassyarduino 0:e3fb1267e3c3 64 #include <string.h>
cassyarduino 0:e3fb1267e3c3 65
cassyarduino 0:e3fb1267e3c3 66 struct arp_hdr {
cassyarduino 0:e3fb1267e3c3 67 struct uip_eth_hdr ethhdr;
cassyarduino 0:e3fb1267e3c3 68 u16_t hwtype;
cassyarduino 0:e3fb1267e3c3 69 u16_t protocol;
cassyarduino 0:e3fb1267e3c3 70 u8_t hwlen;
cassyarduino 0:e3fb1267e3c3 71 u8_t protolen;
cassyarduino 0:e3fb1267e3c3 72 u16_t opcode;
cassyarduino 0:e3fb1267e3c3 73 struct uip_eth_addr shwaddr;
cassyarduino 0:e3fb1267e3c3 74 u16_t sipaddr[2];
cassyarduino 0:e3fb1267e3c3 75 struct uip_eth_addr dhwaddr;
cassyarduino 0:e3fb1267e3c3 76 u16_t dipaddr[2];
cassyarduino 0:e3fb1267e3c3 77 };
cassyarduino 0:e3fb1267e3c3 78
cassyarduino 0:e3fb1267e3c3 79 struct ethip_hdr {
cassyarduino 0:e3fb1267e3c3 80 struct uip_eth_hdr ethhdr;
cassyarduino 0:e3fb1267e3c3 81 /* IP header. */
cassyarduino 0:e3fb1267e3c3 82 u8_t vhl,
cassyarduino 0:e3fb1267e3c3 83 tos,
cassyarduino 0:e3fb1267e3c3 84 len[2],
cassyarduino 0:e3fb1267e3c3 85 ipid[2],
cassyarduino 0:e3fb1267e3c3 86 ipoffset[2],
cassyarduino 0:e3fb1267e3c3 87 ttl,
cassyarduino 0:e3fb1267e3c3 88 proto;
cassyarduino 0:e3fb1267e3c3 89 u16_t ipchksum;
cassyarduino 0:e3fb1267e3c3 90 u16_t srcipaddr[2],
cassyarduino 0:e3fb1267e3c3 91 destipaddr[2];
cassyarduino 0:e3fb1267e3c3 92 };
cassyarduino 0:e3fb1267e3c3 93
cassyarduino 0:e3fb1267e3c3 94 #define ARP_REQUEST 1
cassyarduino 0:e3fb1267e3c3 95 #define ARP_REPLY 2
cassyarduino 0:e3fb1267e3c3 96
cassyarduino 0:e3fb1267e3c3 97 #define ARP_HWTYPE_ETH 1
cassyarduino 0:e3fb1267e3c3 98
cassyarduino 0:e3fb1267e3c3 99 struct arp_entry {
cassyarduino 0:e3fb1267e3c3 100 u16_t ipaddr[2];
cassyarduino 0:e3fb1267e3c3 101 struct uip_eth_addr ethaddr;
cassyarduino 0:e3fb1267e3c3 102 u8_t time;
cassyarduino 0:e3fb1267e3c3 103 };
cassyarduino 0:e3fb1267e3c3 104
cassyarduino 0:e3fb1267e3c3 105 static const struct uip_eth_addr broadcast_ethaddr =
cassyarduino 0:e3fb1267e3c3 106 {{0xff,0xff,0xff,0xff,0xff,0xff}};
cassyarduino 0:e3fb1267e3c3 107 static const u16_t broadcast_ipaddr[2] = {0xffff,0xffff};
cassyarduino 0:e3fb1267e3c3 108
cassyarduino 0:e3fb1267e3c3 109 static struct arp_entry arp_table[UIP_ARPTAB_SIZE];
cassyarduino 0:e3fb1267e3c3 110 static u16_t ipaddr[2];
cassyarduino 0:e3fb1267e3c3 111 static u8_t i, c;
cassyarduino 0:e3fb1267e3c3 112
cassyarduino 0:e3fb1267e3c3 113 static u8_t arptime;
cassyarduino 0:e3fb1267e3c3 114 static u8_t tmpage;
cassyarduino 0:e3fb1267e3c3 115
cassyarduino 0:e3fb1267e3c3 116 #define BUF ((struct arp_hdr *)&uip_buf[0])
cassyarduino 0:e3fb1267e3c3 117 #define IPBUF ((struct ethip_hdr *)&uip_buf[0])
cassyarduino 0:e3fb1267e3c3 118 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 119 /**
cassyarduino 0:e3fb1267e3c3 120 * Initialize the ARP module.
cassyarduino 0:e3fb1267e3c3 121 *
cassyarduino 0:e3fb1267e3c3 122 */
cassyarduino 0:e3fb1267e3c3 123 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 124 void
cassyarduino 0:e3fb1267e3c3 125 uip_arp_init(void)
cassyarduino 0:e3fb1267e3c3 126 {
cassyarduino 0:e3fb1267e3c3 127 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 128 memset(arp_table[i].ipaddr, 0, 4);
cassyarduino 0:e3fb1267e3c3 129 }
cassyarduino 0:e3fb1267e3c3 130 }
cassyarduino 0:e3fb1267e3c3 131 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 132 /**
cassyarduino 0:e3fb1267e3c3 133 * Periodic ARP processing function.
cassyarduino 0:e3fb1267e3c3 134 *
cassyarduino 0:e3fb1267e3c3 135 * This function performs periodic timer processing in the ARP module
cassyarduino 0:e3fb1267e3c3 136 * and should be called at regular intervals. The recommended interval
cassyarduino 0:e3fb1267e3c3 137 * is 10 seconds between the calls.
cassyarduino 0:e3fb1267e3c3 138 *
cassyarduino 0:e3fb1267e3c3 139 */
cassyarduino 0:e3fb1267e3c3 140 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 141 void
cassyarduino 0:e3fb1267e3c3 142 uip_arp_timer(void)
cassyarduino 0:e3fb1267e3c3 143 {
cassyarduino 0:e3fb1267e3c3 144 struct arp_entry *tabptr;
cassyarduino 0:e3fb1267e3c3 145
cassyarduino 0:e3fb1267e3c3 146 ++arptime;
cassyarduino 0:e3fb1267e3c3 147 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 148 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 149 if((tabptr->ipaddr[0] | tabptr->ipaddr[1]) != 0 &&
cassyarduino 0:e3fb1267e3c3 150 arptime - tabptr->time >= UIP_ARP_MAXAGE) {
cassyarduino 0:e3fb1267e3c3 151 memset(tabptr->ipaddr, 0, 4);
cassyarduino 0:e3fb1267e3c3 152 }
cassyarduino 0:e3fb1267e3c3 153 }
cassyarduino 0:e3fb1267e3c3 154
cassyarduino 0:e3fb1267e3c3 155 }
cassyarduino 0:e3fb1267e3c3 156 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 157 static void
cassyarduino 0:e3fb1267e3c3 158 uip_arp_update(u16_t *ipaddr, struct uip_eth_addr *ethaddr)
cassyarduino 0:e3fb1267e3c3 159 {
cassyarduino 0:e3fb1267e3c3 160 register struct arp_entry *tabptr;
cassyarduino 0:e3fb1267e3c3 161 /* Walk through the ARP mapping table and try to find an entry to
cassyarduino 0:e3fb1267e3c3 162 update. If none is found, the IP -> MAC address mapping is
cassyarduino 0:e3fb1267e3c3 163 inserted in the ARP table. */
cassyarduino 0:e3fb1267e3c3 164 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 165
cassyarduino 0:e3fb1267e3c3 166 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 167 /* Only check those entries that are actually in use. */
cassyarduino 0:e3fb1267e3c3 168 if(tabptr->ipaddr[0] != 0 &&
cassyarduino 0:e3fb1267e3c3 169 tabptr->ipaddr[1] != 0) {
cassyarduino 0:e3fb1267e3c3 170
cassyarduino 0:e3fb1267e3c3 171 /* Check if the source IP address of the incoming packet matches
cassyarduino 0:e3fb1267e3c3 172 the IP address in this ARP table entry. */
cassyarduino 0:e3fb1267e3c3 173 if(ipaddr[0] == tabptr->ipaddr[0] &&
cassyarduino 0:e3fb1267e3c3 174 ipaddr[1] == tabptr->ipaddr[1]) {
cassyarduino 0:e3fb1267e3c3 175
cassyarduino 0:e3fb1267e3c3 176 /* An old entry found, update this and return. */
cassyarduino 0:e3fb1267e3c3 177 memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
cassyarduino 0:e3fb1267e3c3 178 tabptr->time = arptime;
cassyarduino 0:e3fb1267e3c3 179
cassyarduino 0:e3fb1267e3c3 180 return;
cassyarduino 0:e3fb1267e3c3 181 }
cassyarduino 0:e3fb1267e3c3 182 }
cassyarduino 0:e3fb1267e3c3 183 }
cassyarduino 0:e3fb1267e3c3 184
cassyarduino 0:e3fb1267e3c3 185 /* If we get here, no existing ARP table entry was found, so we
cassyarduino 0:e3fb1267e3c3 186 create one. */
cassyarduino 0:e3fb1267e3c3 187
cassyarduino 0:e3fb1267e3c3 188 /* First, we try to find an unused entry in the ARP table. */
cassyarduino 0:e3fb1267e3c3 189 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 190 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 191 if(tabptr->ipaddr[0] == 0 &&
cassyarduino 0:e3fb1267e3c3 192 tabptr->ipaddr[1] == 0) {
cassyarduino 0:e3fb1267e3c3 193 break;
cassyarduino 0:e3fb1267e3c3 194 }
cassyarduino 0:e3fb1267e3c3 195 }
cassyarduino 0:e3fb1267e3c3 196
cassyarduino 0:e3fb1267e3c3 197 /* If no unused entry is found, we try to find the oldest entry and
cassyarduino 0:e3fb1267e3c3 198 throw it away. */
cassyarduino 0:e3fb1267e3c3 199 if(i == UIP_ARPTAB_SIZE) {
cassyarduino 0:e3fb1267e3c3 200 tmpage = 0;
cassyarduino 0:e3fb1267e3c3 201 c = 0;
cassyarduino 0:e3fb1267e3c3 202 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 203 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 204 if(arptime - tabptr->time > tmpage) {
cassyarduino 0:e3fb1267e3c3 205 tmpage = arptime - tabptr->time;
cassyarduino 0:e3fb1267e3c3 206 c = i;
cassyarduino 0:e3fb1267e3c3 207 }
cassyarduino 0:e3fb1267e3c3 208 }
cassyarduino 0:e3fb1267e3c3 209 i = c;
cassyarduino 0:e3fb1267e3c3 210 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 211 }
cassyarduino 0:e3fb1267e3c3 212
cassyarduino 0:e3fb1267e3c3 213 /* Now, i is the ARP table entry which we will fill with the new
cassyarduino 0:e3fb1267e3c3 214 information. */
cassyarduino 0:e3fb1267e3c3 215 memcpy(tabptr->ipaddr, ipaddr, 4);
cassyarduino 0:e3fb1267e3c3 216 memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
cassyarduino 0:e3fb1267e3c3 217 tabptr->time = arptime;
cassyarduino 0:e3fb1267e3c3 218 }
cassyarduino 0:e3fb1267e3c3 219 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 220 /**
cassyarduino 0:e3fb1267e3c3 221 * ARP processing for incoming IP packets
cassyarduino 0:e3fb1267e3c3 222 *
cassyarduino 0:e3fb1267e3c3 223 * This function should be called by the device driver when an IP
cassyarduino 0:e3fb1267e3c3 224 * packet has been received. The function will check if the address is
cassyarduino 0:e3fb1267e3c3 225 * in the ARP cache, and if so the ARP cache entry will be
cassyarduino 0:e3fb1267e3c3 226 * refreshed. If no ARP cache entry was found, a new one is created.
cassyarduino 0:e3fb1267e3c3 227 *
cassyarduino 0:e3fb1267e3c3 228 * This function expects an IP packet with a prepended Ethernet header
cassyarduino 0:e3fb1267e3c3 229 * in the uip_buf[] buffer, and the length of the packet in the global
cassyarduino 0:e3fb1267e3c3 230 * variable uip_len.
cassyarduino 0:e3fb1267e3c3 231 */
cassyarduino 0:e3fb1267e3c3 232 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 233 //#if 0
cassyarduino 0:e3fb1267e3c3 234 void
cassyarduino 0:e3fb1267e3c3 235 uip_arp_ipin(void)
cassyarduino 0:e3fb1267e3c3 236 {
cassyarduino 0:e3fb1267e3c3 237 uip_len -= sizeof(struct uip_eth_hdr);
cassyarduino 0:e3fb1267e3c3 238
cassyarduino 0:e3fb1267e3c3 239 /* Only insert/update an entry if the source IP address of the
cassyarduino 0:e3fb1267e3c3 240 incoming IP packet comes from a host on the local network. */
cassyarduino 0:e3fb1267e3c3 241 if((IPBUF->srcipaddr[0] & uip_netmask[0]) !=
cassyarduino 0:e3fb1267e3c3 242 (uip_hostaddr[0] & uip_netmask[0])) {
cassyarduino 0:e3fb1267e3c3 243 return;
cassyarduino 0:e3fb1267e3c3 244 }
cassyarduino 0:e3fb1267e3c3 245 if((IPBUF->srcipaddr[1] & uip_netmask[1]) !=
cassyarduino 0:e3fb1267e3c3 246 (uip_hostaddr[1] & uip_netmask[1])) {
cassyarduino 0:e3fb1267e3c3 247 return;
cassyarduino 0:e3fb1267e3c3 248 }
cassyarduino 0:e3fb1267e3c3 249 uip_arp_update(IPBUF->srcipaddr, &(IPBUF->ethhdr.src));
cassyarduino 0:e3fb1267e3c3 250
cassyarduino 0:e3fb1267e3c3 251 return;
cassyarduino 0:e3fb1267e3c3 252 }
cassyarduino 0:e3fb1267e3c3 253 //#endif /* 0 */
cassyarduino 0:e3fb1267e3c3 254 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 255 /**
cassyarduino 0:e3fb1267e3c3 256 * ARP processing for incoming ARP packets.
cassyarduino 0:e3fb1267e3c3 257 *
cassyarduino 0:e3fb1267e3c3 258 * This function should be called by the device driver when an ARP
cassyarduino 0:e3fb1267e3c3 259 * packet has been received. The function will act differently
cassyarduino 0:e3fb1267e3c3 260 * depending on the ARP packet type: if it is a reply for a request
cassyarduino 0:e3fb1267e3c3 261 * that we previously sent out, the ARP cache will be filled in with
cassyarduino 0:e3fb1267e3c3 262 * the values from the ARP reply. If the incoming ARP packet is an ARP
cassyarduino 0:e3fb1267e3c3 263 * request for our IP address, an ARP reply packet is created and put
cassyarduino 0:e3fb1267e3c3 264 * into the uip_buf[] buffer.
cassyarduino 0:e3fb1267e3c3 265 *
cassyarduino 0:e3fb1267e3c3 266 * When the function returns, the value of the global variable uip_len
cassyarduino 0:e3fb1267e3c3 267 * indicates whether the device driver should send out a packet or
cassyarduino 0:e3fb1267e3c3 268 * not. If uip_len is zero, no packet should be sent. If uip_len is
cassyarduino 0:e3fb1267e3c3 269 * non-zero, it contains the length of the outbound packet that is
cassyarduino 0:e3fb1267e3c3 270 * present in the uip_buf[] buffer.
cassyarduino 0:e3fb1267e3c3 271 *
cassyarduino 0:e3fb1267e3c3 272 * This function expects an ARP packet with a prepended Ethernet
cassyarduino 0:e3fb1267e3c3 273 * header in the uip_buf[] buffer, and the length of the packet in the
cassyarduino 0:e3fb1267e3c3 274 * global variable uip_len.
cassyarduino 0:e3fb1267e3c3 275 */
cassyarduino 0:e3fb1267e3c3 276 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 277 void
cassyarduino 0:e3fb1267e3c3 278 uip_arp_arpin(void)
cassyarduino 0:e3fb1267e3c3 279 {
cassyarduino 0:e3fb1267e3c3 280
cassyarduino 0:e3fb1267e3c3 281 if(uip_len < sizeof(struct arp_hdr)) {
cassyarduino 0:e3fb1267e3c3 282 uip_len = 0;
cassyarduino 0:e3fb1267e3c3 283 return;
cassyarduino 0:e3fb1267e3c3 284 }
cassyarduino 0:e3fb1267e3c3 285 uip_len = 0;
cassyarduino 0:e3fb1267e3c3 286
cassyarduino 0:e3fb1267e3c3 287 switch(BUF->opcode) {
cassyarduino 0:e3fb1267e3c3 288 case HTONS(ARP_REQUEST):
cassyarduino 0:e3fb1267e3c3 289 /* ARP request. If it asked for our address, we send out a
cassyarduino 0:e3fb1267e3c3 290 reply. */
cassyarduino 0:e3fb1267e3c3 291 if(uip_ipaddr_cmp(BUF->dipaddr, uip_hostaddr)) {
cassyarduino 0:e3fb1267e3c3 292 /* First, we register the one who made the request in our ARP
cassyarduino 0:e3fb1267e3c3 293 table, since it is likely that we will do more communication
cassyarduino 0:e3fb1267e3c3 294 with this host in the future. */
cassyarduino 0:e3fb1267e3c3 295 uip_arp_update(BUF->sipaddr, &BUF->shwaddr);
cassyarduino 0:e3fb1267e3c3 296
cassyarduino 0:e3fb1267e3c3 297 /* The reply opcode is 2. */
cassyarduino 0:e3fb1267e3c3 298 BUF->opcode = HTONS(2);
cassyarduino 0:e3fb1267e3c3 299
cassyarduino 0:e3fb1267e3c3 300 memcpy(BUF->dhwaddr.addr, BUF->shwaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 301 memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 302 memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 303 memcpy(BUF->ethhdr.dest.addr, BUF->dhwaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 304
cassyarduino 0:e3fb1267e3c3 305 BUF->dipaddr[0] = BUF->sipaddr[0];
cassyarduino 0:e3fb1267e3c3 306 BUF->dipaddr[1] = BUF->sipaddr[1];
cassyarduino 0:e3fb1267e3c3 307 BUF->sipaddr[0] = uip_hostaddr[0];
cassyarduino 0:e3fb1267e3c3 308 BUF->sipaddr[1] = uip_hostaddr[1];
cassyarduino 0:e3fb1267e3c3 309
cassyarduino 0:e3fb1267e3c3 310 BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);
cassyarduino 0:e3fb1267e3c3 311 uip_len = sizeof(struct arp_hdr);
cassyarduino 0:e3fb1267e3c3 312 }
cassyarduino 0:e3fb1267e3c3 313 break;
cassyarduino 0:e3fb1267e3c3 314 case HTONS(ARP_REPLY):
cassyarduino 0:e3fb1267e3c3 315 /* ARP reply. We insert or update the ARP table if it was meant
cassyarduino 0:e3fb1267e3c3 316 for us. */
cassyarduino 0:e3fb1267e3c3 317 if(uip_ipaddr_cmp(BUF->dipaddr, uip_hostaddr)) {
cassyarduino 0:e3fb1267e3c3 318 uip_arp_update(BUF->sipaddr, &BUF->shwaddr);
cassyarduino 0:e3fb1267e3c3 319 }
cassyarduino 0:e3fb1267e3c3 320 break;
cassyarduino 0:e3fb1267e3c3 321 }
cassyarduino 0:e3fb1267e3c3 322
cassyarduino 0:e3fb1267e3c3 323 return;
cassyarduino 0:e3fb1267e3c3 324 }
cassyarduino 0:e3fb1267e3c3 325 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 326 /**
cassyarduino 0:e3fb1267e3c3 327 * Prepend Ethernet header to an outbound IP packet and see if we need
cassyarduino 0:e3fb1267e3c3 328 * to send out an ARP request.
cassyarduino 0:e3fb1267e3c3 329 *
cassyarduino 0:e3fb1267e3c3 330 * This function should be called before sending out an IP packet. The
cassyarduino 0:e3fb1267e3c3 331 * function checks the destination IP address of the IP packet to see
cassyarduino 0:e3fb1267e3c3 332 * what Ethernet MAC address that should be used as a destination MAC
cassyarduino 0:e3fb1267e3c3 333 * address on the Ethernet.
cassyarduino 0:e3fb1267e3c3 334 *
cassyarduino 0:e3fb1267e3c3 335 * If the destination IP address is in the local network (determined
cassyarduino 0:e3fb1267e3c3 336 * by logical ANDing of netmask and our IP address), the function
cassyarduino 0:e3fb1267e3c3 337 * checks the ARP cache to see if an entry for the destination IP
cassyarduino 0:e3fb1267e3c3 338 * address is found. If so, an Ethernet header is prepended and the
cassyarduino 0:e3fb1267e3c3 339 * function returns. If no ARP cache entry is found for the
cassyarduino 0:e3fb1267e3c3 340 * destination IP address, the packet in the uip_buf[] is replaced by
cassyarduino 0:e3fb1267e3c3 341 * an ARP request packet for the IP address. The IP packet is dropped
cassyarduino 0:e3fb1267e3c3 342 * and it is assumed that they higher level protocols (e.g., TCP)
cassyarduino 0:e3fb1267e3c3 343 * eventually will retransmit the dropped packet.
cassyarduino 0:e3fb1267e3c3 344 *
cassyarduino 0:e3fb1267e3c3 345 * If the destination IP address is not on the local network, the IP
cassyarduino 0:e3fb1267e3c3 346 * address of the default router is used instead.
cassyarduino 0:e3fb1267e3c3 347 *
cassyarduino 0:e3fb1267e3c3 348 * When the function returns, a packet is present in the uip_buf[]
cassyarduino 0:e3fb1267e3c3 349 * buffer, and the length of the packet is in the global variable
cassyarduino 0:e3fb1267e3c3 350 * uip_len.
cassyarduino 0:e3fb1267e3c3 351 */
cassyarduino 0:e3fb1267e3c3 352 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 353 void
cassyarduino 0:e3fb1267e3c3 354 uip_arp_out(void)
cassyarduino 0:e3fb1267e3c3 355 {
cassyarduino 0:e3fb1267e3c3 356 struct arp_entry *tabptr;
cassyarduino 0:e3fb1267e3c3 357
cassyarduino 0:e3fb1267e3c3 358 /* Find the destination IP address in the ARP table and construct
cassyarduino 0:e3fb1267e3c3 359 the Ethernet header. If the destination IP addres isn't on the
cassyarduino 0:e3fb1267e3c3 360 local network, we use the default router's IP address instead.
cassyarduino 0:e3fb1267e3c3 361
cassyarduino 0:e3fb1267e3c3 362 If not ARP table entry is found, we overwrite the original IP
cassyarduino 0:e3fb1267e3c3 363 packet with an ARP request for the IP address. */
cassyarduino 0:e3fb1267e3c3 364
cassyarduino 0:e3fb1267e3c3 365 /* First check if destination is a local broadcast. */
cassyarduino 0:e3fb1267e3c3 366 if(uip_ipaddr_cmp(IPBUF->destipaddr, broadcast_ipaddr)) {
cassyarduino 0:e3fb1267e3c3 367 memcpy(IPBUF->ethhdr.dest.addr, broadcast_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 368 } else {
cassyarduino 0:e3fb1267e3c3 369 /* Check if the destination address is on the local network. */
cassyarduino 0:e3fb1267e3c3 370 if(!uip_ipaddr_maskcmp(IPBUF->destipaddr, uip_hostaddr, uip_netmask)) {
cassyarduino 0:e3fb1267e3c3 371 /* Destination address was not on the local network, so we need to
cassyarduino 0:e3fb1267e3c3 372 use the default router's IP address instead of the destination
cassyarduino 0:e3fb1267e3c3 373 address when determining the MAC address. */
cassyarduino 0:e3fb1267e3c3 374 uip_ipaddr_copy(ipaddr, uip_draddr);
cassyarduino 0:e3fb1267e3c3 375 } else {
cassyarduino 0:e3fb1267e3c3 376 /* Else, we use the destination IP address. */
cassyarduino 0:e3fb1267e3c3 377 uip_ipaddr_copy(ipaddr, IPBUF->destipaddr);
cassyarduino 0:e3fb1267e3c3 378 }
cassyarduino 0:e3fb1267e3c3 379
cassyarduino 0:e3fb1267e3c3 380 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
cassyarduino 0:e3fb1267e3c3 381 tabptr = &arp_table[i];
cassyarduino 0:e3fb1267e3c3 382 if(uip_ipaddr_cmp(ipaddr, tabptr->ipaddr)) {
cassyarduino 0:e3fb1267e3c3 383 break;
cassyarduino 0:e3fb1267e3c3 384 }
cassyarduino 0:e3fb1267e3c3 385 }
cassyarduino 0:e3fb1267e3c3 386
cassyarduino 0:e3fb1267e3c3 387 if(i == UIP_ARPTAB_SIZE) {
cassyarduino 0:e3fb1267e3c3 388 /* The destination address was not in our ARP table, so we
cassyarduino 0:e3fb1267e3c3 389 overwrite the IP packet with an ARP request. */
cassyarduino 0:e3fb1267e3c3 390
cassyarduino 0:e3fb1267e3c3 391 memset(BUF->ethhdr.dest.addr, 0xff, 6);
cassyarduino 0:e3fb1267e3c3 392 memset(BUF->dhwaddr.addr, 0x00, 6);
cassyarduino 0:e3fb1267e3c3 393 memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 394 memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 395
cassyarduino 0:e3fb1267e3c3 396 uip_ipaddr_copy(BUF->dipaddr, ipaddr);
cassyarduino 0:e3fb1267e3c3 397 uip_ipaddr_copy(BUF->sipaddr, uip_hostaddr);
cassyarduino 0:e3fb1267e3c3 398 BUF->opcode = HTONS(ARP_REQUEST); /* ARP request. */
cassyarduino 0:e3fb1267e3c3 399 BUF->hwtype = HTONS(ARP_HWTYPE_ETH);
cassyarduino 0:e3fb1267e3c3 400 BUF->protocol = HTONS(UIP_ETHTYPE_IP);
cassyarduino 0:e3fb1267e3c3 401 BUF->hwlen = 6;
cassyarduino 0:e3fb1267e3c3 402 BUF->protolen = 4;
cassyarduino 0:e3fb1267e3c3 403 BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);
cassyarduino 0:e3fb1267e3c3 404
cassyarduino 0:e3fb1267e3c3 405 uip_appdata = &uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN];
cassyarduino 0:e3fb1267e3c3 406
cassyarduino 0:e3fb1267e3c3 407 uip_len = sizeof(struct arp_hdr);
cassyarduino 0:e3fb1267e3c3 408 return;
cassyarduino 0:e3fb1267e3c3 409 }
cassyarduino 0:e3fb1267e3c3 410
cassyarduino 0:e3fb1267e3c3 411 /* Build an ethernet header. */
cassyarduino 0:e3fb1267e3c3 412 memcpy(IPBUF->ethhdr.dest.addr, tabptr->ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 413 }
cassyarduino 0:e3fb1267e3c3 414 memcpy(IPBUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
cassyarduino 0:e3fb1267e3c3 415
cassyarduino 0:e3fb1267e3c3 416 IPBUF->ethhdr.type = HTONS(UIP_ETHTYPE_IP);
cassyarduino 0:e3fb1267e3c3 417
cassyarduino 0:e3fb1267e3c3 418 uip_len += sizeof(struct uip_eth_hdr);
cassyarduino 0:e3fb1267e3c3 419 }
cassyarduino 0:e3fb1267e3c3 420 /*-----------------------------------------------------------------------------------*/
cassyarduino 0:e3fb1267e3c3 421
cassyarduino 0:e3fb1267e3c3 422 /** @} */
cassyarduino 0:e3fb1267e3c3 423 /** @} */