1/** 2 * @file 3 * AutoIP Automatic LinkLocal IP Configuration 4 * 5 */ 6 7/* 8 * 9 * Copyright (c) 2007 Dominik Spies <kontakt@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@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@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 (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 */ 108static void autoip_handle_arp_conflict(struct netif *netif); 109 110/* creates a pseudo random LL IP-Address for a network interface */ 111static void autoip_create_addr(struct netif *netif, struct ip_addr *IPAddr); 112 113/* sends an ARP announce */ 114static err_t autoip_arp_announce(struct netif *netif); 115 116/* configure interface for use with current LL IP-Address */ 117static err_t autoip_bind(struct netif *netif); 118 119/** 120 * Initialize this module 121 */ 122void autoip_init(void) 123{ 124 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_init()\n")); 125} 126 127/** 128 * Handle a IP address conflict after an ARP conflict detection 129 */ 130static void autoip_handle_arp_conflict(struct netif *netif) 131{ 132 /* Somehow detect if we are defending or retreating */ 133 unsigned char defend = 1; /* tbd */ 134 135 if (defend) { 136 if (netif->autoip->lastconflict > 0) { 137 /* retreat, there was a conflicting ARP in the last 138 * DEFEND_INTERVAL seconds 139 */ 140 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 141 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n")); 142 143 /* TODO: close all TCP sessions */ 144 autoip_start(netif); 145 } else { 146 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 147 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n")); 148 autoip_arp_announce(netif); 149 netif->autoip->lastconflict = 150 DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND; 151 } 152 } else { 153 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 154 ("autoip_handle_arp_conflict(): we do not defend, retreating\n")); 155 /* TODO: close all TCP sessions */ 156 autoip_start(netif); 157 } 158} 159 160/** 161 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255 162 * 163 * @param netif network interface on which create the IP-Address 164 * @param IPAddr ip address to initialize 165 */ 166static void autoip_create_addr(struct netif *netif, struct ip_addr *IPAddr) 167{ 168 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255 169 * compliant to RFC 3927 Section 2.1 170 * We have 254 * 256 possibilities */ 171 172 u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif)); 173 174 addr += netif->autoip->tried_llipaddr; 175 addr = AUTOIP_NET | (addr & 0xffff); 176 /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 177 178 if (addr < AUTOIP_RANGE_START) { 179 addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 180 } 181 if (addr > AUTOIP_RANGE_END) { 182 addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1; 183 } 184 LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) && 185 (addr <= AUTOIP_RANGE_END)); 186 IPAddr->addr = htonl(addr); 187 188 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 189 ("autoip_create_addr(): tried_llipaddr=%" U16_F ", 0x%08" X32_F 190 "\n", (u16_t) (netif->autoip->tried_llipaddr), 191 (u32_t) (IPAddr->addr))); 192} 193 194/** 195 * Sends an ARP announce from a network interface 196 * 197 * @param netif network interface used to send the announce 198 */ 199static err_t autoip_arp_announce(struct netif *netif) 200{ 201 return etharp_raw(netif, (struct eth_addr *) netif->hwaddr, ðbroadcast, 202 (struct eth_addr *) netif->hwaddr, 203 &netif->autoip->llipaddr, ðzero, 204 &netif->autoip->llipaddr, ARP_REQUEST); 205} 206 207/** 208 * Configure interface for use with current LL IP-Address 209 * 210 * @param netif network interface to configure with current LL IP-Address 211 */ 212static err_t autoip_bind(struct netif *netif) 213{ 214 struct autoip *autoip = netif->autoip; 215 struct ip_addr sn_mask, gw_addr; 216 217 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 218 ("autoip_bind(netif=%p) %c%c%" U16_F " 0x%08" X32_F "\n", 219 (void *) netif, netif->name[0], netif->name[1], 220 (u16_t) netif->num, autoip->llipaddr.addr)); 221 222 IP4_ADDR(&sn_mask, 255, 255, 0, 0); 223 IP4_ADDR(&gw_addr, 0, 0, 0, 0); 224 225 netif_set_ipaddr(netif, &autoip->llipaddr); 226 netif_set_netmask(netif, &sn_mask); 227 netif_set_gw(netif, &gw_addr); 228 229 /* bring the interface up */ 230 netif_set_up(netif); 231 232 return ERR_OK; 233} 234 235/** 236 * Start AutoIP client 237 * 238 * @param netif network interface on which start the AutoIP client 239 */ 240err_t autoip_start(struct netif * netif) 241{ 242 struct autoip *autoip = netif->autoip; 243 err_t result = ERR_OK; 244 245 if (netif_is_up(netif)) { 246 netif_set_down(netif); 247 } 248 249 /* Set IP-Address, Netmask and Gateway to 0 to make sure that 250 * ARP Packets are formed correctly 251 */ 252 netif->ip_addr.addr = 0; 253 netif->netmask.addr = 0; 254 netif->gw.addr = 0; 255 256 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, 257 ("autoip_start(netif=%p) %c%c%" U16_F "\n", (void *) netif, 258 netif->name[0], netif->name[1], (u16_t) netif->num)); 259 if (autoip == NULL) { 260 /* no AutoIP client attached yet? */ 261 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 262 ("autoip_start(): starting new AUTOIP client\n")); 263 autoip = mem_malloc(sizeof(struct autoip)); 264 if (autoip == NULL) { 265 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 266 ("autoip_start(): could not allocate autoip\n")); 267 return ERR_MEM; 268 } 269 memset(autoip, 0, sizeof(struct autoip)); 270 /* store this AutoIP client in the netif */ 271 netif->autoip = autoip; 272 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 273 ("autoip_start(): allocated autoip")); 274 } else { 275 autoip->state = AUTOIP_STATE_OFF; 276 autoip->ttw = 0; 277 autoip->sent_num = 0; 278 memset(&autoip->llipaddr, 0, sizeof(struct ip_addr)); 279 autoip->lastconflict = 0; 280 } 281 282 autoip_create_addr(netif, &(autoip->llipaddr)); 283 autoip->tried_llipaddr++; 284 autoip->state = AUTOIP_STATE_PROBING; 285 autoip->sent_num = 0; 286 287 /* time to wait to first probe, this is randomly 288 * choosen out of 0 to PROBE_WAIT seconds. 289 * compliant to RFC 3927 Section 2.2.1 290 */ 291 autoip->ttw = 292 (u16_t) (LWIP_AUTOIP_RAND(netif) % 293 (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND)); 294 295 /* 296 * if we tried more then MAX_CONFLICTS we must limit our rate for 297 * accquiring and probing address 298 * compliant to RFC 3927 Section 2.2.1 299 */ 300 301 if (autoip->tried_llipaddr > MAX_CONFLICTS) { 302 autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND; 303 } 304 305 return result; 306} 307 308/** 309 * Stop AutoIP client 310 * 311 * @param netif network interface on which stop the AutoIP client 312 */ 313err_t autoip_stop(struct netif * netif) 314{ 315 netif->autoip->state = AUTOIP_STATE_OFF; 316 netif_set_down(netif); 317 return ERR_OK; 318} 319 320/** 321 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds 322 */ 323void autoip_tmr() 324{ 325 struct netif *netif = netif_list; 326 327 /* loop through netif's */ 328 while (netif != NULL) { 329 /* only act on AutoIP configured interfaces */ 330 if (netif->autoip != NULL) { 331 if (netif->autoip->lastconflict > 0) { 332 netif->autoip->lastconflict--; 333 } 334 335 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, 336 ("autoip_tmr() AutoIP-State: %" U16_F ", ttw=%" U16_F 337 "\n", (u16_t) (netif->autoip->state), 338 netif->autoip->ttw)); 339 340 switch (netif->autoip->state) { 341 case AUTOIP_STATE_PROBING: 342 if (netif->autoip->ttw > 0) { 343 netif->autoip->ttw--; 344 } else { 345 if (netif->autoip->sent_num == PROBE_NUM) { 346 netif->autoip->state = AUTOIP_STATE_ANNOUNCING; 347 netif->autoip->sent_num = 0; 348 netif->autoip->ttw = 349 ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND; 350 } else { 351 etharp_request(netif, &(netif->autoip->llipaddr)); 352 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 353 ("autoip_tmr() PROBING Sent Probe\n")); 354 netif->autoip->sent_num++; 355 /* calculate time to wait to next probe */ 356 netif->autoip->ttw = 357 (u16_t) ((LWIP_AUTOIP_RAND(netif) % 358 ((PROBE_MAX - 359 PROBE_MIN) * 360 AUTOIP_TICKS_PER_SECOND)) + 361 PROBE_MIN * AUTOIP_TICKS_PER_SECOND); 362 } 363 } 364 break; 365 366 case AUTOIP_STATE_ANNOUNCING: 367 if (netif->autoip->ttw > 0) { 368 netif->autoip->ttw--; 369 } else { 370 if (netif->autoip->sent_num == 0) { 371 /* We are here the first time, so we waited ANNOUNCE_WAIT seconds 372 * Now we can bind to an IP address and use it 373 */ 374 autoip_bind(netif); 375 } 376 377 if (netif->autoip->sent_num == ANNOUNCE_NUM) { 378 netif->autoip->state = AUTOIP_STATE_BOUND; 379 netif->autoip->sent_num = 0; 380 netif->autoip->ttw = 0; 381 } else { 382 autoip_arp_announce(netif); 383 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, 384 ("autoip_tmr() ANNOUNCING Sent Announce\n")); 385 netif->autoip->sent_num++; 386 netif->autoip->ttw = 387 ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND; 388 } 389 } 390 break; 391 } 392 } 393 /* proceed to next network interface */ 394 netif = netif->next; 395 } 396} 397 398/** 399 * Handles every incoming ARP Packet, called by etharp_arp_input. 400 * 401 * @param netif network interface to use for autoip processing 402 * @param hdr Incoming ARP packet 403 */ 404void autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr) 405{ 406 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_arp_reply()\n")); 407 if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) { 408 /* when ip.src == llipaddr && hw.src != netif->hwaddr 409 * 410 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr 411 * we have a conflict and must solve it 412 */ 413 struct ip_addr sipaddr, dipaddr; 414 struct eth_addr netifaddr; 415 416 netifaddr.addr[0] = netif->hwaddr[0]; 417 netifaddr.addr[1] = netif->hwaddr[1]; 418 netifaddr.addr[2] = netif->hwaddr[2]; 419 netifaddr.addr[3] = netif->hwaddr[3]; 420 netifaddr.addr[4] = netif->hwaddr[4]; 421 netifaddr.addr[5] = netif->hwaddr[5]; 422 423 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without 424 * structure packing (not using structure copy which breaks strict-aliasing rules). 425 */ 426 SMEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr)); 427 SMEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr)); 428 429 if ((netif->autoip->state == AUTOIP_STATE_PROBING) || 430 ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) && 431 (netif->autoip->sent_num == 0))) { 432 /* RFC 3927 Section 2.2.1: 433 * from beginning to after ANNOUNCE_WAIT 434 * seconds we have a conflict if 435 * ip.src == llipaddr OR 436 * ip.dst == llipaddr && hw.src != own hwaddr 437 */ 438 if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) || 439 (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) && 440 !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) { 441 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 442 ("autoip_arp_reply(): Probe Conflict detected\n")); 443 autoip_start(netif); 444 } 445 } else { 446 /* RFC 3927 Section 2.5: 447 * in any state we have a conflict if 448 * ip.src == llipaddr && hw.src != own hwaddr 449 */ 450 if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) && 451 !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) { 452 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, 453 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n")); 454 autoip_handle_arp_conflict(netif); 455 } 456 } 457 } 458} 459 460#endif /* LWIP_AUTOIP */ 461