ban4jp - / Mbed 2 deprecated uIP-1-0_webserver

uIP 1.0 based webserver for LPC1114 + ENC28J60

Dependencies:   mbed TMP102

uip/uip_arp.c@0:685224d2f66d, 2014-06-14 (annotated)

Committer:
ban4jp
Date:
Sat Jun 14 16:02:21 2014 +0000
Revision:
0:685224d2f66d
Child:
3:a2715e9c7737
initial commit.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ban4jp 0:685224d2f66d 1 /**
ban4jp 0:685224d2f66d 2 * \addtogroup uip
ban4jp 0:685224d2f66d 3 * @{
ban4jp 0:685224d2f66d 4 */
ban4jp 0:685224d2f66d 5
ban4jp 0:685224d2f66d 6 /**
ban4jp 0:685224d2f66d 7 * \defgroup uiparp uIP Address Resolution Protocol
ban4jp 0:685224d2f66d 8 * @{
ban4jp 0:685224d2f66d 9 *
ban4jp 0:685224d2f66d 10 * The Address Resolution Protocol ARP is used for mapping between IP
ban4jp 0:685224d2f66d 11 * addresses and link level addresses such as the Ethernet MAC
ban4jp 0:685224d2f66d 12 * addresses. ARP uses broadcast queries to ask for the link level
ban4jp 0:685224d2f66d 13 * address of a known IP address and the host which is configured with
ban4jp 0:685224d2f66d 14 * the IP address for which the query was meant, will respond with its
ban4jp 0:685224d2f66d 15 * link level address.
ban4jp 0:685224d2f66d 16 *
ban4jp 0:685224d2f66d 17 * \note This ARP implementation only supports Ethernet.
ban4jp 0:685224d2f66d 18 */
ban4jp 0:685224d2f66d 19
ban4jp 0:685224d2f66d 20 /**
ban4jp 0:685224d2f66d 21 * \file
ban4jp 0:685224d2f66d 22 * Implementation of the ARP Address Resolution Protocol.
ban4jp 0:685224d2f66d 23 * \author Adam Dunkels <adam@dunkels.com>
ban4jp 0:685224d2f66d 24 *
ban4jp 0:685224d2f66d 25 */
ban4jp 0:685224d2f66d 26
ban4jp 0:685224d2f66d 27 /*
ban4jp 0:685224d2f66d 28 * Copyright (c) 2001-2003, Adam Dunkels.
ban4jp 0:685224d2f66d 29 * All rights reserved.
ban4jp 0:685224d2f66d 30 *
ban4jp 0:685224d2f66d 31 * Redistribution and use in source and binary forms, with or without
ban4jp 0:685224d2f66d 32 * modification, are permitted provided that the following conditions
ban4jp 0:685224d2f66d 33 * are met:
ban4jp 0:685224d2f66d 34 * 1. Redistributions of source code must retain the above copyright
ban4jp 0:685224d2f66d 35 * notice, this list of conditions and the following disclaimer.
ban4jp 0:685224d2f66d 36 * 2. Redistributions in binary form must reproduce the above copyright
ban4jp 0:685224d2f66d 37 * notice, this list of conditions and the following disclaimer in the
ban4jp 0:685224d2f66d 38 * documentation and/or other materials provided with the distribution.
ban4jp 0:685224d2f66d 39 * 3. The name of the author may not be used to endorse or promote
ban4jp 0:685224d2f66d 40 * products derived from this software without specific prior
ban4jp 0:685224d2f66d 41 * written permission.
ban4jp 0:685224d2f66d 42 *
ban4jp 0:685224d2f66d 43 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
ban4jp 0:685224d2f66d 44 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
ban4jp 0:685224d2f66d 45 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ban4jp 0:685224d2f66d 46 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
ban4jp 0:685224d2f66d 47 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
ban4jp 0:685224d2f66d 48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
ban4jp 0:685224d2f66d 49 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
ban4jp 0:685224d2f66d 50 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
ban4jp 0:685224d2f66d 51 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
ban4jp 0:685224d2f66d 52 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
ban4jp 0:685224d2f66d 53 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
ban4jp 0:685224d2f66d 54 *
ban4jp 0:685224d2f66d 55 * This file is part of the uIP TCP/IP stack.
ban4jp 0:685224d2f66d 56 *
ban4jp 0:685224d2f66d 57 * $Id: uip_arp.c,v 1.8 2006/06/02 23:36:21 adam Exp $
ban4jp 0:685224d2f66d 58 *
ban4jp 0:685224d2f66d 59 */
ban4jp 0:685224d2f66d 60
ban4jp 0:685224d2f66d 61
ban4jp 0:685224d2f66d 62 #include "uip_arp.h"
ban4jp 0:685224d2f66d 63
ban4jp 0:685224d2f66d 64 #include <string.h>
ban4jp 0:685224d2f66d 65
ban4jp 0:685224d2f66d 66 struct arp_hdr {
ban4jp 0:685224d2f66d 67 struct uip_eth_hdr ethhdr;
ban4jp 0:685224d2f66d 68 u16_t hwtype;
ban4jp 0:685224d2f66d 69 u16_t protocol;
ban4jp 0:685224d2f66d 70 u8_t hwlen;
ban4jp 0:685224d2f66d 71 u8_t protolen;
ban4jp 0:685224d2f66d 72 u16_t opcode;
ban4jp 0:685224d2f66d 73 struct uip_eth_addr shwaddr;
ban4jp 0:685224d2f66d 74 u16_t sipaddr[2];
ban4jp 0:685224d2f66d 75 struct uip_eth_addr dhwaddr;
ban4jp 0:685224d2f66d 76 u16_t dipaddr[2];
ban4jp 0:685224d2f66d 77 };
ban4jp 0:685224d2f66d 78
ban4jp 0:685224d2f66d 79 struct ethip_hdr {
ban4jp 0:685224d2f66d 80 struct uip_eth_hdr ethhdr;
ban4jp 0:685224d2f66d 81 /* IP header. */
ban4jp 0:685224d2f66d 82 u8_t vhl,
ban4jp 0:685224d2f66d 83 tos,
ban4jp 0:685224d2f66d 84 len[2],
ban4jp 0:685224d2f66d 85 ipid[2],
ban4jp 0:685224d2f66d 86 ipoffset[2],
ban4jp 0:685224d2f66d 87 ttl,
ban4jp 0:685224d2f66d 88 proto;
ban4jp 0:685224d2f66d 89 u16_t ipchksum;
ban4jp 0:685224d2f66d 90 u16_t srcipaddr[2],
ban4jp 0:685224d2f66d 91 destipaddr[2];
ban4jp 0:685224d2f66d 92 };
ban4jp 0:685224d2f66d 93
ban4jp 0:685224d2f66d 94 #define ARP_REQUEST 1
ban4jp 0:685224d2f66d 95 #define ARP_REPLY 2
ban4jp 0:685224d2f66d 96
ban4jp 0:685224d2f66d 97 #define ARP_HWTYPE_ETH 1
ban4jp 0:685224d2f66d 98
ban4jp 0:685224d2f66d 99 struct arp_entry {
ban4jp 0:685224d2f66d 100 u16_t ipaddr[2];
ban4jp 0:685224d2f66d 101 struct uip_eth_addr ethaddr;
ban4jp 0:685224d2f66d 102 u8_t time;
ban4jp 0:685224d2f66d 103 };
ban4jp 0:685224d2f66d 104
ban4jp 0:685224d2f66d 105 static const struct uip_eth_addr broadcast_ethaddr =
ban4jp 0:685224d2f66d 106 {{0xff,0xff,0xff,0xff,0xff,0xff}};
ban4jp 0:685224d2f66d 107 static const u16_t broadcast_ipaddr[2] = {0xffff,0xffff};
ban4jp 0:685224d2f66d 108
ban4jp 0:685224d2f66d 109 static struct arp_entry arp_table[UIP_ARPTAB_SIZE];
ban4jp 0:685224d2f66d 110 static u16_t ipaddr[2];
ban4jp 0:685224d2f66d 111 static u8_t i, c;
ban4jp 0:685224d2f66d 112
ban4jp 0:685224d2f66d 113 static u8_t arptime;
ban4jp 0:685224d2f66d 114 static u8_t tmpage;
ban4jp 0:685224d2f66d 115
ban4jp 0:685224d2f66d 116 #define BUF ((struct arp_hdr *)&uip_buf[0])
ban4jp 0:685224d2f66d 117 #define IPBUF ((struct ethip_hdr *)&uip_buf[0])
ban4jp 0:685224d2f66d 118 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 119 /**
ban4jp 0:685224d2f66d 120 * Initialize the ARP module.
ban4jp 0:685224d2f66d 121 *
ban4jp 0:685224d2f66d 122 */
ban4jp 0:685224d2f66d 123 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 124 void
ban4jp 0:685224d2f66d 125 uip_arp_init(void)
ban4jp 0:685224d2f66d 126 {
ban4jp 0:685224d2f66d 127 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 128 memset(arp_table[i].ipaddr, 0, 4);
ban4jp 0:685224d2f66d 129 }
ban4jp 0:685224d2f66d 130 }
ban4jp 0:685224d2f66d 131 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 132 /**
ban4jp 0:685224d2f66d 133 * Periodic ARP processing function.
ban4jp 0:685224d2f66d 134 *
ban4jp 0:685224d2f66d 135 * This function performs periodic timer processing in the ARP module
ban4jp 0:685224d2f66d 136 * and should be called at regular intervals. The recommended interval
ban4jp 0:685224d2f66d 137 * is 10 seconds between the calls.
ban4jp 0:685224d2f66d 138 *
ban4jp 0:685224d2f66d 139 */
ban4jp 0:685224d2f66d 140 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 141 void
ban4jp 0:685224d2f66d 142 uip_arp_timer(void)
ban4jp 0:685224d2f66d 143 {
ban4jp 0:685224d2f66d 144 struct arp_entry *tabptr;
ban4jp 0:685224d2f66d 145
ban4jp 0:685224d2f66d 146 ++arptime;
ban4jp 0:685224d2f66d 147 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 148 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 149 if((tabptr->ipaddr[0] | tabptr->ipaddr[1]) != 0 &&
ban4jp 0:685224d2f66d 150 arptime - tabptr->time >= UIP_ARP_MAXAGE) {
ban4jp 0:685224d2f66d 151 memset(tabptr->ipaddr, 0, 4);
ban4jp 0:685224d2f66d 152 }
ban4jp 0:685224d2f66d 153 }
ban4jp 0:685224d2f66d 154
ban4jp 0:685224d2f66d 155 }
ban4jp 0:685224d2f66d 156 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 157 static void
ban4jp 0:685224d2f66d 158 uip_arp_update(u16_t *ipaddr, struct uip_eth_addr *ethaddr)
ban4jp 0:685224d2f66d 159 {
ban4jp 0:685224d2f66d 160 register struct arp_entry *tabptr;
ban4jp 0:685224d2f66d 161 /* Walk through the ARP mapping table and try to find an entry to
ban4jp 0:685224d2f66d 162 update. If none is found, the IP -> MAC address mapping is
ban4jp 0:685224d2f66d 163 inserted in the ARP table. */
ban4jp 0:685224d2f66d 164 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 165
ban4jp 0:685224d2f66d 166 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 167 /* Only check those entries that are actually in use. */
ban4jp 0:685224d2f66d 168 if(tabptr->ipaddr[0] != 0 &&
ban4jp 0:685224d2f66d 169 tabptr->ipaddr[1] != 0) {
ban4jp 0:685224d2f66d 170
ban4jp 0:685224d2f66d 171 /* Check if the source IP address of the incoming packet matches
ban4jp 0:685224d2f66d 172 the IP address in this ARP table entry. */
ban4jp 0:685224d2f66d 173 if(ipaddr[0] == tabptr->ipaddr[0] &&
ban4jp 0:685224d2f66d 174 ipaddr[1] == tabptr->ipaddr[1]) {
ban4jp 0:685224d2f66d 175
ban4jp 0:685224d2f66d 176 /* An old entry found, update this and return. */
ban4jp 0:685224d2f66d 177 memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
ban4jp 0:685224d2f66d 178 tabptr->time = arptime;
ban4jp 0:685224d2f66d 179
ban4jp 0:685224d2f66d 180 return;
ban4jp 0:685224d2f66d 181 }
ban4jp 0:685224d2f66d 182 }
ban4jp 0:685224d2f66d 183 }
ban4jp 0:685224d2f66d 184
ban4jp 0:685224d2f66d 185 /* If we get here, no existing ARP table entry was found, so we
ban4jp 0:685224d2f66d 186 create one. */
ban4jp 0:685224d2f66d 187
ban4jp 0:685224d2f66d 188 /* First, we try to find an unused entry in the ARP table. */
ban4jp 0:685224d2f66d 189 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 190 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 191 if(tabptr->ipaddr[0] == 0 &&
ban4jp 0:685224d2f66d 192 tabptr->ipaddr[1] == 0) {
ban4jp 0:685224d2f66d 193 break;
ban4jp 0:685224d2f66d 194 }
ban4jp 0:685224d2f66d 195 }
ban4jp 0:685224d2f66d 196
ban4jp 0:685224d2f66d 197 /* If no unused entry is found, we try to find the oldest entry and
ban4jp 0:685224d2f66d 198 throw it away. */
ban4jp 0:685224d2f66d 199 if(i == UIP_ARPTAB_SIZE) {
ban4jp 0:685224d2f66d 200 tmpage = 0;
ban4jp 0:685224d2f66d 201 c = 0;
ban4jp 0:685224d2f66d 202 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 203 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 204 if(arptime - tabptr->time > tmpage) {
ban4jp 0:685224d2f66d 205 tmpage = arptime - tabptr->time;
ban4jp 0:685224d2f66d 206 c = i;
ban4jp 0:685224d2f66d 207 }
ban4jp 0:685224d2f66d 208 }
ban4jp 0:685224d2f66d 209 i = c;
ban4jp 0:685224d2f66d 210 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 211 }
ban4jp 0:685224d2f66d 212
ban4jp 0:685224d2f66d 213 /* Now, i is the ARP table entry which we will fill with the new
ban4jp 0:685224d2f66d 214 information. */
ban4jp 0:685224d2f66d 215 memcpy(tabptr->ipaddr, ipaddr, 4);
ban4jp 0:685224d2f66d 216 memcpy(tabptr->ethaddr.addr, ethaddr->addr, 6);
ban4jp 0:685224d2f66d 217 tabptr->time = arptime;
ban4jp 0:685224d2f66d 218 }
ban4jp 0:685224d2f66d 219 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 220 /**
ban4jp 0:685224d2f66d 221 * ARP processing for incoming IP packets
ban4jp 0:685224d2f66d 222 *
ban4jp 0:685224d2f66d 223 * This function should be called by the device driver when an IP
ban4jp 0:685224d2f66d 224 * packet has been received. The function will check if the address is
ban4jp 0:685224d2f66d 225 * in the ARP cache, and if so the ARP cache entry will be
ban4jp 0:685224d2f66d 226 * refreshed. If no ARP cache entry was found, a new one is created.
ban4jp 0:685224d2f66d 227 *
ban4jp 0:685224d2f66d 228 * This function expects an IP packet with a prepended Ethernet header
ban4jp 0:685224d2f66d 229 * in the uip_buf[] buffer, and the length of the packet in the global
ban4jp 0:685224d2f66d 230 * variable uip_len.
ban4jp 0:685224d2f66d 231 */
ban4jp 0:685224d2f66d 232 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 233 #if 0
ban4jp 0:685224d2f66d 234 void
ban4jp 0:685224d2f66d 235 uip_arp_ipin(void)
ban4jp 0:685224d2f66d 236 {
ban4jp 0:685224d2f66d 237 uip_len -= sizeof(struct uip_eth_hdr);
ban4jp 0:685224d2f66d 238
ban4jp 0:685224d2f66d 239 /* Only insert/update an entry if the source IP address of the
ban4jp 0:685224d2f66d 240 incoming IP packet comes from a host on the local network. */
ban4jp 0:685224d2f66d 241 if((IPBUF->srcipaddr[0] & uip_netmask[0]) !=
ban4jp 0:685224d2f66d 242 (uip_hostaddr[0] & uip_netmask[0])) {
ban4jp 0:685224d2f66d 243 return;
ban4jp 0:685224d2f66d 244 }
ban4jp 0:685224d2f66d 245 if((IPBUF->srcipaddr[1] & uip_netmask[1]) !=
ban4jp 0:685224d2f66d 246 (uip_hostaddr[1] & uip_netmask[1])) {
ban4jp 0:685224d2f66d 247 return;
ban4jp 0:685224d2f66d 248 }
ban4jp 0:685224d2f66d 249 uip_arp_update(IPBUF->srcipaddr, &(IPBUF->ethhdr.src));
ban4jp 0:685224d2f66d 250
ban4jp 0:685224d2f66d 251 return;
ban4jp 0:685224d2f66d 252 }
ban4jp 0:685224d2f66d 253 #endif /* 0 */
ban4jp 0:685224d2f66d 254 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 255 /**
ban4jp 0:685224d2f66d 256 * ARP processing for incoming ARP packets.
ban4jp 0:685224d2f66d 257 *
ban4jp 0:685224d2f66d 258 * This function should be called by the device driver when an ARP
ban4jp 0:685224d2f66d 259 * packet has been received. The function will act differently
ban4jp 0:685224d2f66d 260 * depending on the ARP packet type: if it is a reply for a request
ban4jp 0:685224d2f66d 261 * that we previously sent out, the ARP cache will be filled in with
ban4jp 0:685224d2f66d 262 * the values from the ARP reply. If the incoming ARP packet is an ARP
ban4jp 0:685224d2f66d 263 * request for our IP address, an ARP reply packet is created and put
ban4jp 0:685224d2f66d 264 * into the uip_buf[] buffer.
ban4jp 0:685224d2f66d 265 *
ban4jp 0:685224d2f66d 266 * When the function returns, the value of the global variable uip_len
ban4jp 0:685224d2f66d 267 * indicates whether the device driver should send out a packet or
ban4jp 0:685224d2f66d 268 * not. If uip_len is zero, no packet should be sent. If uip_len is
ban4jp 0:685224d2f66d 269 * non-zero, it contains the length of the outbound packet that is
ban4jp 0:685224d2f66d 270 * present in the uip_buf[] buffer.
ban4jp 0:685224d2f66d 271 *
ban4jp 0:685224d2f66d 272 * This function expects an ARP packet with a prepended Ethernet
ban4jp 0:685224d2f66d 273 * header in the uip_buf[] buffer, and the length of the packet in the
ban4jp 0:685224d2f66d 274 * global variable uip_len.
ban4jp 0:685224d2f66d 275 */
ban4jp 0:685224d2f66d 276 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 277 void
ban4jp 0:685224d2f66d 278 uip_arp_arpin(void)
ban4jp 0:685224d2f66d 279 {
ban4jp 0:685224d2f66d 280
ban4jp 0:685224d2f66d 281 if(uip_len < sizeof(struct arp_hdr)) {
ban4jp 0:685224d2f66d 282 uip_len = 0;
ban4jp 0:685224d2f66d 283 return;
ban4jp 0:685224d2f66d 284 }
ban4jp 0:685224d2f66d 285 uip_len = 0;
ban4jp 0:685224d2f66d 286
ban4jp 0:685224d2f66d 287 switch(BUF->opcode) {
ban4jp 0:685224d2f66d 288 case HTONS(ARP_REQUEST):
ban4jp 0:685224d2f66d 289 /* ARP request. If it asked for our address, we send out a
ban4jp 0:685224d2f66d 290 reply. */
ban4jp 0:685224d2f66d 291 if(uip_ipaddr_cmp(BUF->dipaddr, uip_hostaddr)) {
ban4jp 0:685224d2f66d 292 /* First, we register the one who made the request in our ARP
ban4jp 0:685224d2f66d 293 table, since it is likely that we will do more communication
ban4jp 0:685224d2f66d 294 with this host in the future. */
ban4jp 0:685224d2f66d 295 uip_arp_update(BUF->sipaddr, &BUF->shwaddr);
ban4jp 0:685224d2f66d 296
ban4jp 0:685224d2f66d 297 /* The reply opcode is 2. */
ban4jp 0:685224d2f66d 298 BUF->opcode = HTONS(2);
ban4jp 0:685224d2f66d 299
ban4jp 0:685224d2f66d 300 memcpy(BUF->dhwaddr.addr, BUF->shwaddr.addr, 6);
ban4jp 0:685224d2f66d 301 memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 302 memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 303 memcpy(BUF->ethhdr.dest.addr, BUF->dhwaddr.addr, 6);
ban4jp 0:685224d2f66d 304
ban4jp 0:685224d2f66d 305 BUF->dipaddr[0] = BUF->sipaddr[0];
ban4jp 0:685224d2f66d 306 BUF->dipaddr[1] = BUF->sipaddr[1];
ban4jp 0:685224d2f66d 307 BUF->sipaddr[0] = uip_hostaddr[0];
ban4jp 0:685224d2f66d 308 BUF->sipaddr[1] = uip_hostaddr[1];
ban4jp 0:685224d2f66d 309
ban4jp 0:685224d2f66d 310 BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);
ban4jp 0:685224d2f66d 311 uip_len = sizeof(struct arp_hdr);
ban4jp 0:685224d2f66d 312 }
ban4jp 0:685224d2f66d 313 break;
ban4jp 0:685224d2f66d 314 case HTONS(ARP_REPLY):
ban4jp 0:685224d2f66d 315 /* ARP reply. We insert or update the ARP table if it was meant
ban4jp 0:685224d2f66d 316 for us. */
ban4jp 0:685224d2f66d 317 if(uip_ipaddr_cmp(BUF->dipaddr, uip_hostaddr)) {
ban4jp 0:685224d2f66d 318 uip_arp_update(BUF->sipaddr, &BUF->shwaddr);
ban4jp 0:685224d2f66d 319 }
ban4jp 0:685224d2f66d 320 break;
ban4jp 0:685224d2f66d 321 }
ban4jp 0:685224d2f66d 322
ban4jp 0:685224d2f66d 323 return;
ban4jp 0:685224d2f66d 324 }
ban4jp 0:685224d2f66d 325 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 326 /**
ban4jp 0:685224d2f66d 327 * Prepend Ethernet header to an outbound IP packet and see if we need
ban4jp 0:685224d2f66d 328 * to send out an ARP request.
ban4jp 0:685224d2f66d 329 *
ban4jp 0:685224d2f66d 330 * This function should be called before sending out an IP packet. The
ban4jp 0:685224d2f66d 331 * function checks the destination IP address of the IP packet to see
ban4jp 0:685224d2f66d 332 * what Ethernet MAC address that should be used as a destination MAC
ban4jp 0:685224d2f66d 333 * address on the Ethernet.
ban4jp 0:685224d2f66d 334 *
ban4jp 0:685224d2f66d 335 * If the destination IP address is in the local network (determined
ban4jp 0:685224d2f66d 336 * by logical ANDing of netmask and our IP address), the function
ban4jp 0:685224d2f66d 337 * checks the ARP cache to see if an entry for the destination IP
ban4jp 0:685224d2f66d 338 * address is found. If so, an Ethernet header is prepended and the
ban4jp 0:685224d2f66d 339 * function returns. If no ARP cache entry is found for the
ban4jp 0:685224d2f66d 340 * destination IP address, the packet in the uip_buf[] is replaced by
ban4jp 0:685224d2f66d 341 * an ARP request packet for the IP address. The IP packet is dropped
ban4jp 0:685224d2f66d 342 * and it is assumed that they higher level protocols (e.g., TCP)
ban4jp 0:685224d2f66d 343 * eventually will retransmit the dropped packet.
ban4jp 0:685224d2f66d 344 *
ban4jp 0:685224d2f66d 345 * If the destination IP address is not on the local network, the IP
ban4jp 0:685224d2f66d 346 * address of the default router is used instead.
ban4jp 0:685224d2f66d 347 *
ban4jp 0:685224d2f66d 348 * When the function returns, a packet is present in the uip_buf[]
ban4jp 0:685224d2f66d 349 * buffer, and the length of the packet is in the global variable
ban4jp 0:685224d2f66d 350 * uip_len.
ban4jp 0:685224d2f66d 351 */
ban4jp 0:685224d2f66d 352 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 353 void
ban4jp 0:685224d2f66d 354 uip_arp_out(void)
ban4jp 0:685224d2f66d 355 {
ban4jp 0:685224d2f66d 356 struct arp_entry *tabptr;
ban4jp 0:685224d2f66d 357
ban4jp 0:685224d2f66d 358 /* Find the destination IP address in the ARP table and construct
ban4jp 0:685224d2f66d 359 the Ethernet header. If the destination IP addres isn't on the
ban4jp 0:685224d2f66d 360 local network, we use the default router's IP address instead.
ban4jp 0:685224d2f66d 361
ban4jp 0:685224d2f66d 362 If not ARP table entry is found, we overwrite the original IP
ban4jp 0:685224d2f66d 363 packet with an ARP request for the IP address. */
ban4jp 0:685224d2f66d 364
ban4jp 0:685224d2f66d 365 /* First check if destination is a local broadcast. */
ban4jp 0:685224d2f66d 366 if(uip_ipaddr_cmp(IPBUF->destipaddr, broadcast_ipaddr)) {
ban4jp 0:685224d2f66d 367 memcpy(IPBUF->ethhdr.dest.addr, broadcast_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 368 } else {
ban4jp 0:685224d2f66d 369 /* Check if the destination address is on the local network. */
ban4jp 0:685224d2f66d 370 if(!uip_ipaddr_maskcmp(IPBUF->destipaddr, uip_hostaddr, uip_netmask)) {
ban4jp 0:685224d2f66d 371 /* Destination address was not on the local network, so we need to
ban4jp 0:685224d2f66d 372 use the default router's IP address instead of the destination
ban4jp 0:685224d2f66d 373 address when determining the MAC address. */
ban4jp 0:685224d2f66d 374 uip_ipaddr_copy(ipaddr, uip_draddr);
ban4jp 0:685224d2f66d 375 } else {
ban4jp 0:685224d2f66d 376 /* Else, we use the destination IP address. */
ban4jp 0:685224d2f66d 377 uip_ipaddr_copy(ipaddr, IPBUF->destipaddr);
ban4jp 0:685224d2f66d 378 }
ban4jp 0:685224d2f66d 379
ban4jp 0:685224d2f66d 380 for(i = 0; i < UIP_ARPTAB_SIZE; ++i) {
ban4jp 0:685224d2f66d 381 tabptr = &arp_table[i];
ban4jp 0:685224d2f66d 382 if(uip_ipaddr_cmp(ipaddr, tabptr->ipaddr)) {
ban4jp 0:685224d2f66d 383 break;
ban4jp 0:685224d2f66d 384 }
ban4jp 0:685224d2f66d 385 }
ban4jp 0:685224d2f66d 386
ban4jp 0:685224d2f66d 387 if(i == UIP_ARPTAB_SIZE) {
ban4jp 0:685224d2f66d 388 /* The destination address was not in our ARP table, so we
ban4jp 0:685224d2f66d 389 overwrite the IP packet with an ARP request. */
ban4jp 0:685224d2f66d 390
ban4jp 0:685224d2f66d 391 memset(BUF->ethhdr.dest.addr, 0xff, 6);
ban4jp 0:685224d2f66d 392 memset(BUF->dhwaddr.addr, 0x00, 6);
ban4jp 0:685224d2f66d 393 memcpy(BUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 394 memcpy(BUF->shwaddr.addr, uip_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 395
ban4jp 0:685224d2f66d 396 uip_ipaddr_copy(BUF->dipaddr, ipaddr);
ban4jp 0:685224d2f66d 397 uip_ipaddr_copy(BUF->sipaddr, uip_hostaddr);
ban4jp 0:685224d2f66d 398 BUF->opcode = HTONS(ARP_REQUEST); /* ARP request. */
ban4jp 0:685224d2f66d 399 BUF->hwtype = HTONS(ARP_HWTYPE_ETH);
ban4jp 0:685224d2f66d 400 BUF->protocol = HTONS(UIP_ETHTYPE_IP);
ban4jp 0:685224d2f66d 401 BUF->hwlen = 6;
ban4jp 0:685224d2f66d 402 BUF->protolen = 4;
ban4jp 0:685224d2f66d 403 BUF->ethhdr.type = HTONS(UIP_ETHTYPE_ARP);
ban4jp 0:685224d2f66d 404
ban4jp 0:685224d2f66d 405 uip_appdata = &uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN];
ban4jp 0:685224d2f66d 406
ban4jp 0:685224d2f66d 407 uip_len = sizeof(struct arp_hdr);
ban4jp 0:685224d2f66d 408 return;
ban4jp 0:685224d2f66d 409 }
ban4jp 0:685224d2f66d 410
ban4jp 0:685224d2f66d 411 /* Build an ethernet header. */
ban4jp 0:685224d2f66d 412 memcpy(IPBUF->ethhdr.dest.addr, tabptr->ethaddr.addr, 6);
ban4jp 0:685224d2f66d 413 }
ban4jp 0:685224d2f66d 414 memcpy(IPBUF->ethhdr.src.addr, uip_ethaddr.addr, 6);
ban4jp 0:685224d2f66d 415
ban4jp 0:685224d2f66d 416 IPBUF->ethhdr.type = HTONS(UIP_ETHTYPE_IP);
ban4jp 0:685224d2f66d 417
ban4jp 0:685224d2f66d 418 uip_len += sizeof(struct uip_eth_hdr);
ban4jp 0:685224d2f66d 419 }
ban4jp 0:685224d2f66d 420 /*-----------------------------------------------------------------------------------*/
ban4jp 0:685224d2f66d 421
ban4jp 0:685224d2f66d 422 /** @} */
ban4jp 0:685224d2f66d 423 /** @} */