lib/drivers/lwip/src/core/ipv4/autoip.c

   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   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, struct ip_addr *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 /**
 135  * Handle a IP address conflict after an ARP conflict detection
 136  */
 137 static void
 138 autoip_handle_arp_conflict(struct netif *netif)
 139 {
 140   /* Somehow detect if we are defending or retreating */
 141   unsigned char defend = 1; /* tbd */
 142
 143   if(defend) {
 144     if(netif->autoip->lastconflict > 0) {
 145       /* retreat, there was a conflicting ARP in the last
 146        * DEFEND_INTERVAL seconds
 147        */
 148       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
 149         ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
 150
 151       /* TODO: close all TCP sessions */
 152       autoip_start(netif);
 153     } else {
 154       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
 155         ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
 156       autoip_arp_announce(netif);
 157       netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
 158     }
 159   } else {
 160     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
 161       ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
 162     /* TODO: close all TCP sessions */
 163     autoip_start(netif);
 164   }
 165 }
 166
 167 /**
 168  * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
 169  *
 170  * @param netif network interface on which create the IP-Address
 171  * @param ipaddr ip address to initialize
 172  */
 173 static void
 174 autoip_create_addr(struct netif *netif, struct ip_addr *ipaddr)
 175 {
 176   /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
 177    * compliant to RFC 3927 Section 2.1
 178    * We have 254 * 256 possibilities */
 179
 180   u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
 181   addr += netif->autoip->tried_llipaddr;
 182   addr = AUTOIP_NET | (addr & 0xffff);
 183   /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */
 184
 185   if (addr < AUTOIP_RANGE_START) {
 186     addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
 187   }
 188   if (addr > AUTOIP_RANGE_END) {
 189     addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
 190   }
 191   LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
 192     (addr <= AUTOIP_RANGE_END));
 193   ipaddr->addr = htonl(addr);
 194
 195   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
 196     ("autoip_create_addr(): tried_llipaddr=%"U16_F", 0x%08"X32_F"\n",
 197     (u16_t)(netif->autoip->tried_llipaddr), (u32_t)(ipaddr->addr)));
 198 }
 199
 200 /**
 201  * Sends an ARP probe from a network interface
 202  *
 203  * @param netif network interface used to send the probe
 204  */
 205 static err_t
 206 autoip_arp_probe(struct netif *netif)
 207 {
 208   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
 209     (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, &ethzero,
 210     &netif->autoip->llipaddr, ARP_REQUEST);
 211 }
 212
 213 /**
 214  * Sends an ARP announce from a network interface
 215  *
 216  * @param netif network interface used to send the announce
 217  */
 218 static err_t
 219 autoip_arp_announce(struct netif *netif)
 220 {
 221   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
 222     (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, &ethzero,
 223     &netif->autoip->llipaddr, ARP_REQUEST);
 224 }
 225
 226 /**
 227  * Configure interface for use with current LL IP-Address
 228  *
 229  * @param netif network interface to configure with current LL IP-Address
 230  */
 231 static err_t
 232 autoip_bind(struct netif *netif)
 233 {
 234   struct autoip *autoip = netif->autoip;
 235   struct ip_addr sn_mask, gw_addr;
 236
 237   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 238     ("autoip_bind(netif=%p) %c%c%"U16_F" 0x%08"X32_F"\n",
 239     (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num, autoip->llipaddr.addr));
 240
 241   IP4_ADDR(&sn_mask, 255, 255, 0, 0);
 242   IP4_ADDR(&gw_addr, 0, 0, 0, 0);
 243
 244   netif_set_ipaddr(netif, &autoip->llipaddr);
 245   netif_set_netmask(netif, &sn_mask);
 246   netif_set_gw(netif, &gw_addr);
 247
 248   /* bring the interface up */
 249   netif_set_up(netif);
 250
 251   return ERR_OK;
 252 }
 253
 254 /**
 255  * Start AutoIP client
 256  *
 257  * @param netif network interface on which start the AutoIP client
 258  */
 259 err_t
 260 autoip_start(struct netif *netif)
 261 {
 262   struct autoip *autoip = netif->autoip;
 263   err_t result = ERR_OK;
 264
 265   if(netif_is_up(netif)) {
 266     netif_set_down(netif);
 267   }
 268
 269   /* Set IP-Address, Netmask and Gateway to 0 to make sure that
 270    * ARP Packets are formed correctly
 271    */
 272   netif->ip_addr.addr = 0;
 273   netif->netmask.addr = 0;
 274   netif->gw.addr      = 0;
 275
 276   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
 277     ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
 278     netif->name[1], (u16_t)netif->num));
 279   if(autoip == NULL) {
 280     /* no AutoIP client attached yet? */
 281     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 282       ("autoip_start(): starting new AUTOIP client\n"));
 283     autoip = mem_malloc(sizeof(struct autoip));
 284     if(autoip == NULL) {
 285       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 286         ("autoip_start(): could not allocate autoip\n"));
 287       return ERR_MEM;
 288     }
 289     memset( autoip, 0, sizeof(struct autoip));
 290     /* store this AutoIP client in the netif */
 291     netif->autoip = autoip;
 292     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
 293   } else {
 294     autoip->state = AUTOIP_STATE_OFF;
 295     autoip->ttw = 0;
 296     autoip->sent_num = 0;
 297     memset(&autoip->llipaddr, 0, sizeof(struct ip_addr));
 298     autoip->lastconflict = 0;
 299   }
 300
 301   autoip_create_addr(netif, &(autoip->llipaddr));
 302   autoip->tried_llipaddr++;
 303   autoip_start_probing(netif);
 304
 305   return result;
 306 }
 307
 308 static void
 309 autoip_start_probing(struct netif *netif)
 310 {
 311   struct autoip *autoip = netif->autoip;
 312
 313   autoip->state = AUTOIP_STATE_PROBING;
 314   autoip->sent_num = 0;
 315
 316   /* time to wait to first probe, this is randomly
 317    * choosen out of 0 to PROBE_WAIT seconds.
 318    * compliant to RFC 3927 Section 2.2.1
 319    */
 320   autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
 321
 322   /*
 323    * if we tried more then MAX_CONFLICTS we must limit our rate for
 324    * accquiring and probing address
 325    * compliant to RFC 3927 Section 2.2.1
 326    */
 327   if(autoip->tried_llipaddr > MAX_CONFLICTS) {
 328     autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
 329   }
 330 }
 331
 332 /**
 333  * Handle a possible change in the network configuration.
 334  *
 335  * If there is an AutoIP address configured, take the interface down
 336  * and begin probing with the same address.
 337  */
 338 void
 339 autoip_network_changed(struct netif *netif)
 340 {
 341   if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
 342     netif_set_down(netif);
 343     autoip_start_probing(netif);
 344   }
 345 }
 346
 347 /**
 348  * Stop AutoIP client
 349  *
 350  * @param netif network interface on which stop the AutoIP client
 351  */
 352 err_t
 353 autoip_stop(struct netif *netif)
 354 {
 355   netif->autoip->state = AUTOIP_STATE_OFF;
 356   netif_set_down(netif);
 357   return ERR_OK;
 358 }
 359
 360 /**
 361  * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
 362  */
 363 void
 364 autoip_tmr()
 365 {
 366   struct netif *netif = netif_list;
 367   /* loop through netif's */
 368   while (netif != NULL) {
 369     /* only act on AutoIP configured interfaces */
 370     if (netif->autoip != NULL) {
 371       if(netif->autoip->lastconflict > 0) {
 372         netif->autoip->lastconflict--;
 373       }
 374
 375       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 376         ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
 377         (u16_t)(netif->autoip->state), netif->autoip->ttw));
 378
 379       switch(netif->autoip->state) {
 380         case AUTOIP_STATE_PROBING:
 381           if(netif->autoip->ttw > 0) {
 382             netif->autoip->ttw--;
 383           } else {
 384             if(netif->autoip->sent_num >= PROBE_NUM) {
 385               netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
 386               netif->autoip->sent_num = 0;
 387               netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
 388             } else {
 389               autoip_arp_probe(netif);
 390               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 391                 ("autoip_tmr() PROBING Sent Probe\n"));
 392               netif->autoip->sent_num++;
 393               /* calculate time to wait to next probe */
 394               netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
 395                 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
 396                 PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
 397             }
 398           }
 399           break;
 400
 401         case AUTOIP_STATE_ANNOUNCING:
 402           if(netif->autoip->ttw > 0) {
 403             netif->autoip->ttw--;
 404           } else {
 405             if(netif->autoip->sent_num == 0) {
 406              /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
 407               * Now we can bind to an IP address and use it.
 408               *
 409               * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
 410               * which counts as an announcement.
 411               */
 412               autoip_bind(netif);
 413             } else {
 414               autoip_arp_announce(netif);
 415               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
 416                 ("autoip_tmr() ANNOUNCING Sent Announce\n"));
 417             }
 418             netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
 419             netif->autoip->sent_num++;
 420
 421             if(netif->autoip->sent_num >= ANNOUNCE_NUM) {
 422                 netif->autoip->state = AUTOIP_STATE_BOUND;
 423                 netif->autoip->sent_num = 0;
 424                 netif->autoip->ttw = 0;
 425             }
 426           }
 427           break;
 428       }
 429     }
 430     /* proceed to next network interface */
 431     netif = netif->next;
 432   }
 433 }
 434
 435 /**
 436  * Handles every incoming ARP Packet, called by etharp_arp_input.
 437  *
 438  * @param netif network interface to use for autoip processing
 439  * @param hdr Incoming ARP packet
 440  */
 441 void
 442 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
 443 {
 444   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
 445   if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
 446    /* when ip.src == llipaddr && hw.src != netif->hwaddr
 447     *
 448     * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
 449     * we have a conflict and must solve it
 450     */
 451     struct ip_addr sipaddr, dipaddr;
 452     struct eth_addr netifaddr;
 453     netifaddr.addr[0] = netif->hwaddr[0];
 454     netifaddr.addr[1] = netif->hwaddr[1];
 455     netifaddr.addr[2] = netif->hwaddr[2];
 456     netifaddr.addr[3] = netif->hwaddr[3];
 457     netifaddr.addr[4] = netif->hwaddr[4];
 458     netifaddr.addr[5] = netif->hwaddr[5];
 459
 460     /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
 461      * structure packing (not using structure copy which breaks strict-aliasing rules).
 462      */
 463     SMEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr));
 464     SMEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr));
 465
 466     if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
 467         ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
 468          (netif->autoip->sent_num == 0))) {
 469      /* RFC 3927 Section 2.2.1:
 470       * from beginning to after ANNOUNCE_WAIT
 471       * seconds we have a conflict if
 472       * ip.src == llipaddr OR
 473       * ip.dst == llipaddr && hw.src != own hwaddr
 474       */
 475       if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
 476           (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
 477            !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
 478         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
 479           ("autoip_arp_reply(): Probe Conflict detected\n"));
 480         autoip_start(netif);
 481       }
 482     } else {
 483      /* RFC 3927 Section 2.5:
 484       * in any state we have a conflict if
 485       * ip.src == llipaddr && hw.src != own hwaddr
 486       */
 487       if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
 488           !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
 489         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
 490           ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
 491         autoip_handle_arp_conflict(netif);
 492       }
 493     }
 494   }
 495 }
 496
 497 #endif /* LWIP_AUTOIP */