1 /** 2 * @file 3 * AutoIP Automatic LinkLocal IP Configuration 4 * 5 */ 6 7 /* 8 * 9 * Copyright (c) 2007 Dominik Spies <kontakt (at) dspies.de> 10 * All rights reserved. 11 * 12 * Redistribution and use in source and binary forms, with or without modification, 13 * are permitted provided that the following conditions are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright notice, 16 * this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright notice, 18 * this list of conditions and the following disclaimer in the documentation 19 * and/or other materials provided with the distribution. 20 * 3. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 24 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 26 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 28 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 31 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 32 * OF SUCH DAMAGE. 33 * 34 * Author: Dominik Spies <kontakt (at) dspies.de> 35 * 36 * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform 37 * with RFC 3927. 38 * 39 * 40 * Please coordinate changes and requests with Dominik Spies 41 * <kontakt (at) dspies.de> 42 */ 43 44 /******************************************************************************* 45 * USAGE: 46 * 47 * define LWIP_AUTOIP 1 in your lwipopts.h 48 * 49 * If you don't use tcpip.c (so, don't call, you don't call tcpip_init): 50 * - First, call autoip_init(). 51 * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces, 52 * that should be defined in autoip.h. 53 * I recommend a value of 100. The value must divide 1000 with a remainder almost 0. 54 * Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 .... 55 * 56 * Without DHCP: 57 * - Call autoip_start() after netif_add(). 58 * 59 * With DHCP: 60 * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h. 61 * - Configure your DHCP Client. 62 * 63 */ 64 65 #include "lwip/opt.h" 66 67 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */ 68 69 #include "lwip/mem.h" 70 #include "lwip/udp.h" 71 #include "lwip/ip_addr.h" 72 #include "lwip/netif.h" 73 #include "lwip/autoip.h" 74 #include "netif/etharp.h" 75 76 #include <stdlib.h> 77 #include <string.h> 78 79 /* 169.254.0.0 */ 80 #define AUTOIP_NET 0xA9FE0000 81 /* 169.254.1.0 */ 82 #define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100) 83 /* 169.254.254.255 */ 84 #define AUTOIP_RANGE_END (AUTOIP_NET | 0xFEFF) 85 86 87 /** Pseudo random macro based on netif informations. 88 * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */ 89 #ifndef LWIP_AUTOIP_RAND 90 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \ 91 ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \ 92 ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \ 93 ((u32_t)((netif->hwaddr[4]) & 0xff))) + \ 94 (netif->autoip?netif->autoip->tried_llipaddr:0)) 95 #endif /* LWIP_AUTOIP_RAND */ 96 97 /** 98 * Macro that generates the initial IP address to be tried by AUTOIP. 99 * If you want to override this, define it to something else in lwipopts.h. 100 */ 101 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR 102 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \ 103 htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \ 104 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8))) 105 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */ 106 107 /* static functions */ 108 static void autoip_handle_arp_conflict(struct netif *netif); 109 110 /* creates a pseudo random LL IP-Address for a network interface */ 111 static void autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr); 112 113 /* sends an ARP probe */ 114 static err_t autoip_arp_probe(struct netif *netif); 115 116 /* sends an ARP announce */ 117 static err_t autoip_arp_announce(struct netif *netif); 118 119 /* configure interface for use with current LL IP-Address */ 120 static err_t autoip_bind(struct netif *netif); 121 122 /* start sending probes for llipaddr */ 123 static void autoip_start_probing(struct netif *netif); 124 125 /** 126 * Initialize this module 127 */ 128 void 129 autoip_init(void) 130 { 131 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_init()\n")); 132 } 133 134 /** Set a statically allocated struct autoip to work with. 135 * Using this prevents autoip_start to allocate it using mem_malloc. 136 * 137 * @param netif the netif for which to set the struct autoip 138 * @param dhcp (uninitialised) dhcp struct allocated by the application 139 */ 140 void 141 autoip_set_struct(struct netif *netif, struct autoip *autoip) 142 { 143 LWIP_ASSERT("netif != NULL", netif != NULL); 144 LWIP_ASSERT("autoip != NULL", autoip != NULL); 145 LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL); 146 147 /* clear data structure */ 148 memset(autoip, 0, sizeof(struct autoip)); 149 /* autoip->state = AUTOIP_STATE_OFF; */ 150 netif->autoip = autoip; 151 } 152 153 /** Restart AutoIP client and check the next address (conflict detected) 154 * 155 * @param netif The netif under AutoIP control 156 */ 157 static void 158 autoip_restart(struct netif *netif) 159 { 160 netif->autoip->tried_llipaddr++; 161 autoip_start(netif); 162 } 163 164 /** 165 * Handle a IP address conflict after an ARP conflict detection 166 */ 167 static void 168 autoip_handle_arp_conflict(struct netif *netif) 169 { 170 /* Somehow detect if we are defending or retreating */ 171 unsigned char defend = 1; /* tbd */ 172 173 if(defend) { 174 if(netif->autoip->lastconflict > 0) { 175 /* retreat, there was a conflicting ARP in the last 176 * DEFEND_INTERVAL seconds 177 */ 178 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 179 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n")); 180 181 /* TODO: close all TCP sessions */ 182 autoip_restart(netif); 183 } else { 184 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 185 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n")); 186 autoip_arp_announce(netif); 187 netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND; 188 } 189 } else { 190 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 191 ("autoip_handle_arp_conflict(): we do not defend, retreating\n")); 192 /* TODO: close all TCP sessions */ 193 autoip_restart(netif); 194 } 195 } 196 197 /** 198 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255 199 * 200 * @param netif network interface on which create the IP-Address 201 * @param ipaddr ip address to initialize 202 */ 203 static void 204 autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr) 205 { 206 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255 207 * compliant to RFC 3927 Section 2.1 208 * We have 254 * 256 possibilities */ 209 210 u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif)); 211 addr += netif->autoip->tried_llipaddr; 212 addr = AUTOIP_NET | (addr & 0xffff); 213 /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 214 215 if (addr < AUTOIP_RANGE_START) { 216 addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 217 } 218 if (addr > AUTOIP_RANGE_END) { 219 addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 220 } 221 LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) && 222 (addr <= AUTOIP_RANGE_END)); 223 ip4_addr_set_u32(ipaddr, htonl(addr)); 224 225 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 226 ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 227 (u16_t)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), 228 ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr))); 229 } 230 231 /** 232 * Sends an ARP probe from a network interface 233 * 234 * @param netif network interface used to send the probe 235 */ 236 static err_t 237 autoip_arp_probe(struct netif *netif) 238 { 239 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, 240 (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, ðzero, 241 &netif->autoip->llipaddr, ARP_REQUEST); 242 } 243 244 /** 245 * Sends an ARP announce from a network interface 246 * 247 * @param netif network interface used to send the announce 248 */ 249 static err_t 250 autoip_arp_announce(struct netif *netif) 251 { 252 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, 253 (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, ðzero, 254 &netif->autoip->llipaddr, ARP_REQUEST); 255 } 256 257 /** 258 * Configure interface for use with current LL IP-Address 259 * 260 * @param netif network interface to configure with current LL IP-Address 261 */ 262 static err_t 263 autoip_bind(struct netif *netif) 264 { 265 struct autoip *autoip = netif->autoip; 266 ip_addr_t sn_mask, gw_addr; 267 268 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 269 ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 270 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num, 271 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr), 272 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr))); 273 274 IP4_ADDR(&sn_mask, 255, 255, 0, 0); 275 IP4_ADDR(&gw_addr, 0, 0, 0, 0); 276 277 netif_set_ipaddr(netif, &autoip->llipaddr); 278 netif_set_netmask(netif, &sn_mask); 279 netif_set_gw(netif, &gw_addr); 280 281 /* bring the interface up */ 282 netif_set_up(netif); 283 284 return ERR_OK; 285 } 286 287 /** 288 * Start AutoIP client 289 * 290 * @param netif network interface on which start the AutoIP client 291 */ 292 err_t 293 autoip_start(struct netif *netif) 294 { 295 struct autoip *autoip = netif->autoip; 296 err_t result = ERR_OK; 297 298 if(netif_is_up(netif)) { 299 netif_set_down(netif); 300 } 301 302 /* Set IP-Address, Netmask and Gateway to 0 to make sure that 303 * ARP Packets are formed correctly 304 */ 305 ip_addr_set_zero(&netif->ip_addr); 306 ip_addr_set_zero(&netif->netmask); 307 ip_addr_set_zero(&netif->gw); 308 309 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 310 ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], 311 netif->name[1], (u16_t)netif->num)); 312 if(autoip == NULL) { 313 /* no AutoIP client attached yet? */ 314 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 315 ("autoip_start(): starting new AUTOIP client\n")); 316 autoip = (struct autoip *)mem_malloc(sizeof(struct autoip)); 317 if(autoip == NULL) { 318 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 319 ("autoip_start(): could not allocate autoip\n")); 320 return ERR_MEM; 321 } 322 memset(autoip, 0, sizeof(struct autoip)); 323 /* store this AutoIP client in the netif */ 324 netif->autoip = autoip; 325 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip")); 326 } else { 327 autoip->state = AUTOIP_STATE_OFF; 328 autoip->ttw = 0; 329 autoip->sent_num = 0; 330 ip_addr_set_zero(&autoip->llipaddr); 331 autoip->lastconflict = 0; 332 } 333 334 autoip_create_addr(netif, &(autoip->llipaddr)); 335 autoip_start_probing(netif); 336 337 return result; 338 } 339 340 static void 341 autoip_start_probing(struct netif *netif) 342 { 343 struct autoip *autoip = netif->autoip; 344 345 autoip->state = AUTOIP_STATE_PROBING; 346 autoip->sent_num = 0; 347 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 348 ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 349 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr), 350 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr))); 351 352 /* time to wait to first probe, this is randomly 353 * choosen out of 0 to PROBE_WAIT seconds. 354 * compliant to RFC 3927 Section 2.2.1 355 */ 356 autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND)); 357 358 /* 359 * if we tried more then MAX_CONFLICTS we must limit our rate for 360 * accquiring and probing address 361 * compliant to RFC 3927 Section 2.2.1 362 */ 363 if(autoip->tried_llipaddr > MAX_CONFLICTS) { 364 autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND; 365 } 366 } 367 368 /** 369 * Handle a possible change in the network configuration. 370 * 371 * If there is an AutoIP address configured, take the interface down 372 * and begin probing with the same address. 373 */ 374 void 375 autoip_network_changed(struct netif *netif) 376 { 377 if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) { 378 netif_set_down(netif); 379 autoip_start_probing(netif); 380 } 381 } 382 383 /** 384 * Stop AutoIP client 385 * 386 * @param netif network interface on which stop the AutoIP client 387 */ 388 err_t 389 autoip_stop(struct netif *netif) 390 { 391 netif->autoip->state = AUTOIP_STATE_OFF; 392 netif_set_down(netif); 393 return ERR_OK; 394 } 395 396 /** 397 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds 398 */ 399 void 400 autoip_tmr() 401 { 402 struct netif *netif = netif_list; 403 /* loop through netif's */ 404 while (netif != NULL) { 405 /* only act on AutoIP configured interfaces */ 406 if (netif->autoip != NULL) { 407 if(netif->autoip->lastconflict > 0) { 408 netif->autoip->lastconflict--; 409 } 410 411 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 412 ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n", 413 (u16_t)(netif->autoip->state), netif->autoip->ttw)); 414 415 switch(netif->autoip->state) { 416 case AUTOIP_STATE_PROBING: 417 if(netif->autoip->ttw > 0) { 418 netif->autoip->ttw--; 419 } else { 420 if(netif->autoip->sent_num >= PROBE_NUM) { 421 netif->autoip->state = AUTOIP_STATE_ANNOUNCING; 422 netif->autoip->sent_num = 0; 423 netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND; 424 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 425 ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 426 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr), 427 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr))); 428 } else { 429 autoip_arp_probe(netif); 430 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 431 ("autoip_tmr() PROBING Sent Probe\n")); 432 netif->autoip->sent_num++; 433 /* calculate time to wait to next probe */ 434 netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) % 435 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) + 436 PROBE_MIN * AUTOIP_TICKS_PER_SECOND); 437 } 438 } 439 break; 440 441 case AUTOIP_STATE_ANNOUNCING: 442 if(netif->autoip->ttw > 0) { 443 netif->autoip->ttw--; 444 } else { 445 if(netif->autoip->sent_num == 0) { 446 /* We are here the first time, so we waited ANNOUNCE_WAIT seconds 447 * Now we can bind to an IP address and use it. 448 * 449 * autoip_bind calls netif_set_up. This triggers a gratuitous ARP 450 * which counts as an announcement. 451 */ 452 autoip_bind(netif); 453 } else { 454 autoip_arp_announce(netif); 455 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 456 ("autoip_tmr() ANNOUNCING Sent Announce\n")); 457 } 458 netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND; 459 netif->autoip->sent_num++; 460 461 if(netif->autoip->sent_num >= ANNOUNCE_NUM) { 462 netif->autoip->state = AUTOIP_STATE_BOUND; 463 netif->autoip->sent_num = 0; 464 netif->autoip->ttw = 0; 465 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 466 ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n", 467 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr), 468 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr))); 469 } 470 } 471 break; 472 } 473 } 474 /* proceed to next network interface */ 475 netif = netif->next; 476 } 477 } 478 479 /** 480 * Handles every incoming ARP Packet, called by etharp_arp_input. 481 * 482 * @param netif network interface to use for autoip processing 483 * @param hdr Incoming ARP packet 484 */ 485 void 486 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr) 487 { 488 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n")); 489 if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) { 490 /* when ip.src == llipaddr && hw.src != netif->hwaddr 491 * 492 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr 493 * we have a conflict and must solve it 494 */ 495 ip_addr_t sipaddr, dipaddr; 496 struct eth_addr netifaddr; 497 ETHADDR16_COPY(netifaddr.addr, netif->hwaddr); 498 499 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without 500 * structure packing (not using structure copy which breaks strict-aliasing rules). 501 */ 502 IPADDR2_COPY(&sipaddr, &hdr->sipaddr); 503 IPADDR2_COPY(&dipaddr, &hdr->dipaddr); 504 505 if ((netif->autoip->state == AUTOIP_STATE_PROBING) || 506 ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) && 507 (netif->autoip->sent_num == 0))) { 508 /* RFC 3927 Section 2.2.1: 509 * from beginning to after ANNOUNCE_WAIT 510 * seconds we have a conflict if 511 * ip.src == llipaddr OR 512 * ip.dst == llipaddr && hw.src != own hwaddr 513 */ 514 if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) || 515 (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) && 516 !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) { 517 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING, 518 ("autoip_arp_reply(): Probe Conflict detected\n")); 519 autoip_restart(netif); 520 } 521 } else { 522 /* RFC 3927 Section 2.5: 523 * in any state we have a conflict if 524 * ip.src == llipaddr && hw.src != own hwaddr 525 */ 526 if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) && 527 !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) { 528 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING, 529 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n")); 530 autoip_handle_arp_conflict(netif); 531 } 532 } 533 } 534 } 535 536 #endif /* LWIP_AUTOIP */ 537
