sbin/dhclient/dispatch.c

   1 /*      $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $     */
   2
   3 /*
   4  * Copyright 2004 Henning Brauer <henning@openbsd.org>
   5  * Copyright (c) 1995, 1996, 1997, 1998, 1999
   6  * The Internet Software Consortium.   All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of The Internet Software Consortium nor the names
  18  *    of its contributors may be used to endorse or promote products derived
  19  *    from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
  22  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  23  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  25  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
  26  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  28  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  29  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  30  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * This software has been written for the Internet Software Consortium
  36  * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
  37  * Enterprises.  To learn more about the Internet Software Consortium,
  38  * see ``http://www.vix.com/isc''.  To learn more about Vixie
  39  * Enterprises, see ``http://www.vix.com''.
  40  */
  41
  42 #include <sys/cdefs.h>
  43 __FBSDID("$FreeBSD$");
  44
  45 #include "dhcpd.h"
  46
  47 #include <sys/ioctl.h>
  48
  49 #include <net/if_media.h>
  50 #include <ifaddrs.h>
  51 #include <poll.h>
  52
  53 struct protocol *protocols;
  54 struct timeout *timeouts;
  55 static struct timeout *free_timeouts;
  56 static int interfaces_invalidated;
  57 void (*bootp_packet_handler)(struct interface_info *,
  58     struct dhcp_packet *, int, unsigned int,
  59     struct iaddr, struct hardware *);
  60
  61 static int interface_status(struct interface_info *ifinfo);
  62
  63 /*
  64  * Use getifaddrs() to get a list of all the attached interfaces.  For
  65  * each interface that's of type INET and not the loopback interface,
  66  * register that interface with the network I/O software, figure out
  67  * what subnet it's on, and add it to the list of interfaces.
  68  */
  69 void
  70 discover_interfaces(struct interface_info *iface)
  71 {
  72         struct ifaddrs *ifap, *ifa;
  73         struct sockaddr_in foo;
  74         struct ifreq *tif;
  75
  76         if (getifaddrs(&ifap) != 0)
  77                 error("getifaddrs failed");
  78
  79         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
  80                 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
  81                     (ifa->ifa_flags & IFF_POINTOPOINT) ||
  82                     (!(ifa->ifa_flags & IFF_UP)))
  83                         continue;
  84
  85                 if (strcmp(iface->name, ifa->ifa_name))
  86                         continue;
  87
  88                 /*
  89                  * If we have the capability, extract link information
  90                  * and record it in a linked list.
  91                  */
  92                 if (ifa->ifa_addr->sa_family == AF_LINK) {
  93                         struct sockaddr_dl *foo =
  94                             (struct sockaddr_dl *)ifa->ifa_addr;
  95
  96                         iface->index = foo->sdl_index;
  97                         iface->hw_address.hlen = foo->sdl_alen;
  98                         iface->hw_address.htype = HTYPE_ETHER; /* XXX */
  99                         memcpy(iface->hw_address.haddr,
 100                             LLADDR(foo), foo->sdl_alen);
 101                 } else if (ifa->ifa_addr->sa_family == AF_INET) {
 102                         struct iaddr addr;
 103
 104                         memcpy(&foo, ifa->ifa_addr, sizeof(foo));
 105                         if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
 106                                 continue;
 107                         if (!iface->ifp) {
 108                                 int len = IFNAMSIZ + ifa->ifa_addr->sa_len;
 109                                 if ((tif = malloc(len)) == NULL)
 110                                         error("no space to remember ifp");
 111                                 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
 112                                 memcpy(&tif->ifr_addr, ifa->ifa_addr,
 113                                     ifa->ifa_addr->sa_len);
 114                                 iface->ifp = tif;
 115                                 iface->primary_address = foo.sin_addr;
 116                         }
 117                         addr.len = 4;
 118                         memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
 119                 }
 120         }
 121
 122         if (!iface->ifp)
 123                 error("%s: not found", iface->name);
 124
 125         /* Register the interface... */
 126         if_register_receive(iface);
 127         if_register_send(iface);
 128         add_protocol(iface->name, iface->rfdesc, got_one, iface);
 129         freeifaddrs(ifap);
 130 }
 131
 132 void
 133 reinitialize_interfaces(void)
 134 {
 135         interfaces_invalidated = 1;
 136 }
 137
 138 /*
 139  * Wait for packets to come in using poll().  When a packet comes in,
 140  * call receive_packet to receive the packet and possibly strip hardware
 141  * addressing information from it, and then call through the
 142  * bootp_packet_handler hook to try to do something with it.
 143  */
 144 void
 145 dispatch(void)
 146 {
 147         int count, i, to_msec, nfds = 0;
 148         struct protocol *l;
 149         struct pollfd *fds;
 150         time_t howlong;
 151
 152         for (l = protocols; l; l = l->next)
 153                 nfds++;
 154
 155         fds = malloc(nfds * sizeof(struct pollfd));
 156         if (fds == NULL)
 157                 error("Can't allocate poll structures.");
 158
 159         do {
 160                 /*
 161                  * Call any expired timeouts, and then if there's still
 162                  * a timeout registered, time out the select call then.
 163                  */
 164 another:
 165                 if (timeouts) {
 166                         struct timeout *t;
 167
 168                         if (timeouts->when <= cur_time) {
 169                                 t = timeouts;
 170                                 timeouts = timeouts->next;
 171                                 (*(t->func))(t->what);
 172                                 t->next = free_timeouts;
 173                                 free_timeouts = t;
 174                                 goto another;
 175                         }
 176
 177                         /*
 178                          * Figure timeout in milliseconds, and check for
 179                          * potential overflow, so we can cram into an
 180                          * int for poll, while not polling with a
 181                          * negative timeout and blocking indefinitely.
 182                          */
 183                         howlong = timeouts->when - cur_time;
 184                         if (howlong > INT_MAX / 1000)
 185                                 howlong = INT_MAX / 1000;
 186                         to_msec = howlong * 1000;
 187                 } else
 188                         to_msec = -1;
 189
 190                 /* Set up the descriptors to be polled. */
 191                 for (i = 0, l = protocols; l; l = l->next) {
 192                         struct interface_info *ip = l->local;
 193
 194                         if (ip && (l->handler != got_one || !ip->dead)) {
 195                                 fds[i].fd = l->fd;
 196                                 fds[i].events = POLLIN;
 197                                 fds[i].revents = 0;
 198                                 i++;
 199                         }
 200                 }
 201
 202                 if (i == 0)
 203                         error("No live interfaces to poll on - exiting.");
 204
 205                 /* Wait for a packet or a timeout... XXX */
 206                 count = poll(fds, nfds, to_msec);
 207
 208                 /* Not likely to be transitory... */
 209                 if (count == -1) {
 210                         if (errno == EAGAIN || errno == EINTR) {
 211                                 time(&cur_time);
 212                                 continue;
 213                         } else
 214                                 error("poll: %m");
 215                 }
 216
 217                 /* Get the current time... */
 218                 time(&cur_time);
 219
 220                 i = 0;
 221                 for (l = protocols; l; l = l->next) {
 222                         struct interface_info *ip;
 223                         ip = l->local;
 224                         if ((fds[i].revents & (POLLIN | POLLHUP))) {
 225                                 fds[i].revents = 0;
 226                                 if (ip && (l->handler != got_one ||
 227                                     !ip->dead))
 228                                         (*(l->handler))(l);
 229                                 if (interfaces_invalidated)
 230                                         break;
 231                         }
 232                         i++;
 233                 }
 234                 interfaces_invalidated = 0;
 235         } while (1);
 236 }
 237
 238
 239 void
 240 got_one(struct protocol *l)
 241 {
 242         struct sockaddr_in from;
 243         struct hardware hfrom;
 244         struct iaddr ifrom;
 245         ssize_t result;
 246         union {
 247                 /*
 248                  * Packet input buffer.  Must be as large as largest
 249                  * possible MTU.
 250                  */
 251                 unsigned char packbuf[4095];
 252                 struct dhcp_packet packet;
 253         } u;
 254         struct interface_info *ip = l->local;
 255
 256         if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
 257             &hfrom)) == -1) {
 258                 warning("receive_packet failed on %s: %s", ip->name,
 259                     strerror(errno));
 260                 ip->errors++;
 261                 if ((!interface_status(ip)) ||
 262                     (ip->noifmedia && ip->errors > 20)) {
 263                         /* our interface has gone away. */
 264                         warning("Interface %s no longer appears valid.",
 265                             ip->name);
 266                         ip->dead = 1;
 267                         interfaces_invalidated = 1;
 268                         close(l->fd);
 269                         remove_protocol(l);
 270                         free(ip);
 271                 }
 272                 return;
 273         }
 274         if (result == 0)
 275                 return;
 276
 277         if (bootp_packet_handler) {
 278                 ifrom.len = 4;
 279                 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
 280
 281                 (*bootp_packet_handler)(ip, &u.packet, result,
 282                     from.sin_port, ifrom, &hfrom);
 283         }
 284 }
 285
 286 int
 287 interface_status(struct interface_info *ifinfo)
 288 {
 289         char *ifname = ifinfo->name;
 290         int ifsock = ifinfo->rfdesc;
 291         struct ifreq ifr;
 292         struct ifmediareq ifmr;
 293
 294         /* get interface flags */
 295         memset(&ifr, 0, sizeof(ifr));
 296         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 297         if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
 298                 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
 299                 goto inactive;
 300         }
 301
 302         /*
 303          * if one of UP and RUNNING flags is dropped,
 304          * the interface is not active.
 305          */
 306         if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
 307                 goto inactive;
 308
 309         /* Next, check carrier on the interface, if possible */
 310         if (ifinfo->noifmedia)
 311                 goto active;
 312         memset(&ifmr, 0, sizeof(ifmr));
 313         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 314         if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
 315                 if (errno != EINVAL) {
 316                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 317                             ifname);
 318
 319                         ifinfo->noifmedia = 1;
 320                         goto active;
 321                 }
 322                 /*
 323                  * EINVAL (or ENOTTY) simply means that the interface
 324                  * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
 325                  */
 326                 ifinfo->noifmedia = 1;
 327                 goto active;
 328         }
 329         if (ifmr.ifm_status & IFM_AVALID) {
 330                 switch (ifmr.ifm_active & IFM_NMASK) {
 331                 case IFM_ETHER:
 332                 case IFM_IEEE80211:
 333                         if (ifmr.ifm_status & IFM_ACTIVE)
 334                                 goto active;
 335                         else
 336                                 goto inactive;
 337                         break;
 338                 default:
 339                         goto inactive;
 340                 }
 341         }
 342 inactive:
 343         return (0);
 344 active:
 345         return (1);
 346 }
 347
 348 void
 349 add_timeout(time_t when, void (*where)(void *), void *what)
 350 {
 351         struct timeout *t, *q;
 352
 353         /* See if this timeout supersedes an existing timeout. */
 354         t = NULL;
 355         for (q = timeouts; q; q = q->next) {
 356                 if (q->func == where && q->what == what) {
 357                         if (t)
 358                                 t->next = q->next;
 359                         else
 360                                 timeouts = q->next;
 361                         break;
 362                 }
 363                 t = q;
 364         }
 365
 366         /* If we didn't supersede a timeout, allocate a timeout
 367            structure now. */
 368         if (!q) {
 369                 if (free_timeouts) {
 370                         q = free_timeouts;
 371                         free_timeouts = q->next;
 372                         q->func = where;
 373                         q->what = what;
 374                 } else {
 375                         q = malloc(sizeof(struct timeout));
 376                         if (!q)
 377                                 error("Can't allocate timeout structure!");
 378                         q->func = where;
 379                         q->what = what;
 380                 }
 381         }
 382
 383         q->when = when;
 384
 385         /* Now sort this timeout into the timeout list. */
 386
 387         /* Beginning of list? */
 388         if (!timeouts || timeouts->when > q->when) {
 389                 q->next = timeouts;
 390                 timeouts = q;
 391                 return;
 392         }
 393
 394         /* Middle of list? */
 395         for (t = timeouts; t->next; t = t->next) {
 396                 if (t->next->when > q->when) {
 397                         q->next = t->next;
 398                         t->next = q;
 399                         return;
 400                 }
 401         }
 402
 403         /* End of list. */
 404         t->next = q;
 405         q->next = NULL;
 406 }
 407
 408 void
 409 cancel_timeout(void (*where)(void *), void *what)
 410 {
 411         struct timeout *t, *q;
 412
 413         /* Look for this timeout on the list, and unlink it if we find it. */
 414         t = NULL;
 415         for (q = timeouts; q; q = q->next) {
 416                 if (q->func == where && q->what == what) {
 417                         if (t)
 418                                 t->next = q->next;
 419                         else
 420                                 timeouts = q->next;
 421                         break;
 422                 }
 423                 t = q;
 424         }
 425
 426         /* If we found the timeout, put it on the free list. */
 427         if (q) {
 428                 q->next = free_timeouts;
 429                 free_timeouts = q;
 430         }
 431 }
 432
 433 /* Add a protocol to the list of protocols... */
 434 void
 435 add_protocol(char *name, int fd, void (*handler)(struct protocol *),
 436     void *local)
 437 {
 438         struct protocol *p;
 439
 440         p = malloc(sizeof(*p));
 441         if (!p)
 442                 error("can't allocate protocol struct for %s", name);
 443
 444         p->fd = fd;
 445         p->handler = handler;
 446         p->local = local;
 447         p->next = protocols;
 448         protocols = p;
 449 }
 450
 451 void
 452 remove_protocol(struct protocol *proto)
 453 {
 454         struct protocol *p, *next, *prev;
 455
 456         prev = NULL;
 457         for (p = protocols; p; p = next) {
 458                 next = p->next;
 459                 if (p == proto) {
 460                         if (prev)
 461                                 prev->next = p->next;
 462                         else
 463                                 protocols = p->next;
 464                         free(p);
 465                 }
 466         }
 467 }
 468
 469 int
 470 interface_link_status(char *ifname)
 471 {
 472         struct ifmediareq ifmr;
 473         int sock;
 474
 475         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 476                 error("Can't create socket");
 477
 478         memset(&ifmr, 0, sizeof(ifmr));
 479         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 480         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
 481                 /* EINVAL -> link state unknown. treat as active */
 482                 if (errno != EINVAL)
 483                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 484                             ifname);
 485                 close(sock);
 486                 return (1);
 487         }
 488         close(sock);
 489
 490         if (ifmr.ifm_status & IFM_AVALID) {
 491                 switch (ifmr.ifm_active & IFM_NMASK) {
 492                 case IFM_ETHER:
 493                 case IFM_IEEE80211:
 494                         if (ifmr.ifm_status & IFM_ACTIVE)
 495                                 return (1);
 496                         else
 497                                 return (0);
 498                 }
 499         }
 500         return (1);
 501 }