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, live_interfaces, 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                 live_interfaces = 0;
 192                 for (i = 0, l = protocols; l; l = l->next) {
 193                         struct interface_info *ip = l->local;
 194
 195                         if (ip == NULL || ip->dead)
 196                                 continue;
 197                         fds[i].fd = l->fd;
 198                         fds[i].events = POLLIN;
 199                         fds[i].revents = 0;
 200                         i++;
 201                         if (l->handler == got_one)
 202                                 live_interfaces++;
 203                 }
 204                 if (live_interfaces == 0)
 205                         error("No live interfaces to poll on - exiting.");
 206
 207                 /* Wait for a packet or a timeout... XXX */
 208                 count = poll(fds, nfds, to_msec);
 209
 210                 /* Not likely to be transitory... */
 211                 if (count == -1) {
 212                         if (errno == EAGAIN || errno == EINTR) {
 213                                 time(&cur_time);
 214                                 continue;
 215                         } else
 216                                 error("poll: %m");
 217                 }
 218
 219                 /* Get the current time... */
 220                 time(&cur_time);
 221
 222                 i = 0;
 223                 for (l = protocols; l; l = l->next) {
 224                         struct interface_info *ip;
 225                         ip = l->local;
 226                         if ((fds[i].revents & (POLLIN | POLLHUP))) {
 227                                 fds[i].revents = 0;
 228                                 if (ip && (l->handler != got_one ||
 229                                     !ip->dead))
 230                                         (*(l->handler))(l);
 231                                 if (interfaces_invalidated)
 232                                         break;
 233                         }
 234                         i++;
 235                 }
 236                 interfaces_invalidated = 0;
 237         } while (1);
 238 }
 239
 240
 241 void
 242 got_one(struct protocol *l)
 243 {
 244         struct sockaddr_in from;
 245         struct hardware hfrom;
 246         struct iaddr ifrom;
 247         ssize_t result;
 248         union {
 249                 /*
 250                  * Packet input buffer.  Must be as large as largest
 251                  * possible MTU.
 252                  */
 253                 unsigned char packbuf[4095];
 254                 struct dhcp_packet packet;
 255         } u;
 256         struct interface_info *ip = l->local;
 257
 258         if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
 259             &hfrom)) == -1) {
 260                 warning("receive_packet failed on %s: %s", ip->name,
 261                     strerror(errno));
 262                 ip->errors++;
 263                 if ((!interface_status(ip)) ||
 264                     (ip->noifmedia && ip->errors > 20)) {
 265                         /* our interface has gone away. */
 266                         warning("Interface %s no longer appears valid.",
 267                             ip->name);
 268                         ip->dead = 1;
 269                         interfaces_invalidated = 1;
 270                         close(l->fd);
 271                         remove_protocol(l);
 272                         free(ip);
 273                 }
 274                 return;
 275         }
 276         if (result == 0)
 277                 return;
 278
 279         if (bootp_packet_handler) {
 280                 ifrom.len = 4;
 281                 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
 282
 283                 (*bootp_packet_handler)(ip, &u.packet, result,
 284                     from.sin_port, ifrom, &hfrom);
 285         }
 286 }
 287
 288 int
 289 interface_status(struct interface_info *ifinfo)
 290 {
 291         char *ifname = ifinfo->name;
 292         int ifsock = ifinfo->rfdesc;
 293         struct ifreq ifr;
 294         struct ifmediareq ifmr;
 295
 296         /* get interface flags */
 297         memset(&ifr, 0, sizeof(ifr));
 298         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 299         if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
 300                 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
 301                 goto inactive;
 302         }
 303
 304         /*
 305          * if one of UP and RUNNING flags is dropped,
 306          * the interface is not active.
 307          */
 308         if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
 309                 goto inactive;
 310
 311         /* Next, check carrier on the interface, if possible */
 312         if (ifinfo->noifmedia)
 313                 goto active;
 314         memset(&ifmr, 0, sizeof(ifmr));
 315         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 316         if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
 317                 if (errno != EINVAL) {
 318                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 319                             ifname);
 320
 321                         ifinfo->noifmedia = 1;
 322                         goto active;
 323                 }
 324                 /*
 325                  * EINVAL (or ENOTTY) simply means that the interface
 326                  * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
 327                  */
 328                 ifinfo->noifmedia = 1;
 329                 goto active;
 330         }
 331         if (ifmr.ifm_status & IFM_AVALID) {
 332                 switch (ifmr.ifm_active & IFM_NMASK) {
 333                 case IFM_ETHER:
 334                 case IFM_IEEE80211:
 335                         if (ifmr.ifm_status & IFM_ACTIVE)
 336                                 goto active;
 337                         else
 338                                 goto inactive;
 339                         break;
 340                 default:
 341                         goto inactive;
 342                 }
 343         }
 344 inactive:
 345         return (0);
 346 active:
 347         return (1);
 348 }
 349
 350 void
 351 add_timeout(time_t when, void (*where)(void *), void *what)
 352 {
 353         struct timeout *t, *q;
 354
 355         /* See if this timeout supersedes an existing timeout. */
 356         t = NULL;
 357         for (q = timeouts; q; q = q->next) {
 358                 if (q->func == where && q->what == what) {
 359                         if (t)
 360                                 t->next = q->next;
 361                         else
 362                                 timeouts = q->next;
 363                         break;
 364                 }
 365                 t = q;
 366         }
 367
 368         /* If we didn't supersede a timeout, allocate a timeout
 369            structure now. */
 370         if (!q) {
 371                 if (free_timeouts) {
 372                         q = free_timeouts;
 373                         free_timeouts = q->next;
 374                         q->func = where;
 375                         q->what = what;
 376                 } else {
 377                         q = malloc(sizeof(struct timeout));
 378                         if (!q)
 379                                 error("Can't allocate timeout structure!");
 380                         q->func = where;
 381                         q->what = what;
 382                 }
 383         }
 384
 385         q->when = when;
 386
 387         /* Now sort this timeout into the timeout list. */
 388
 389         /* Beginning of list? */
 390         if (!timeouts || timeouts->when > q->when) {
 391                 q->next = timeouts;
 392                 timeouts = q;
 393                 return;
 394         }
 395
 396         /* Middle of list? */
 397         for (t = timeouts; t->next; t = t->next) {
 398                 if (t->next->when > q->when) {
 399                         q->next = t->next;
 400                         t->next = q;
 401                         return;
 402                 }
 403         }
 404
 405         /* End of list. */
 406         t->next = q;
 407         q->next = NULL;
 408 }
 409
 410 void
 411 cancel_timeout(void (*where)(void *), void *what)
 412 {
 413         struct timeout *t, *q;
 414
 415         /* Look for this timeout on the list, and unlink it if we find it. */
 416         t = NULL;
 417         for (q = timeouts; q; q = q->next) {
 418                 if (q->func == where && q->what == what) {
 419                         if (t)
 420                                 t->next = q->next;
 421                         else
 422                                 timeouts = q->next;
 423                         break;
 424                 }
 425                 t = q;
 426         }
 427
 428         /* If we found the timeout, put it on the free list. */
 429         if (q) {
 430                 q->next = free_timeouts;
 431                 free_timeouts = q;
 432         }
 433 }
 434
 435 /* Add a protocol to the list of protocols... */
 436 void
 437 add_protocol(char *name, int fd, void (*handler)(struct protocol *),
 438     void *local)
 439 {
 440         struct protocol *p;
 441
 442         p = malloc(sizeof(*p));
 443         if (!p)
 444                 error("can't allocate protocol struct for %s", name);
 445
 446         p->fd = fd;
 447         p->handler = handler;
 448         p->local = local;
 449         p->next = protocols;
 450         protocols = p;
 451 }
 452
 453 void
 454 remove_protocol(struct protocol *proto)
 455 {
 456         struct protocol *p, *next, *prev;
 457
 458         prev = NULL;
 459         for (p = protocols; p; p = next) {
 460                 next = p->next;
 461                 if (p == proto) {
 462                         if (prev)
 463                                 prev->next = p->next;
 464                         else
 465                                 protocols = p->next;
 466                         free(p);
 467                 }
 468         }
 469 }
 470
 471 int
 472 interface_link_status(char *ifname)
 473 {
 474         struct ifmediareq ifmr;
 475         int sock;
 476
 477         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 478                 error("Can't create socket");
 479
 480         memset(&ifmr, 0, sizeof(ifmr));
 481         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 482         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
 483                 /* EINVAL -> link state unknown. treat as active */
 484                 if (errno != EINVAL)
 485                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 486                             ifname);
 487                 close(sock);
 488                 return (1);
 489         }
 490         close(sock);
 491
 492         if (ifmr.ifm_status & IFM_AVALID) {
 493                 switch (ifmr.ifm_active & IFM_NMASK) {
 494                 case IFM_ETHER:
 495                 case IFM_IEEE80211:
 496                         if (ifmr.ifm_status & IFM_ACTIVE)
 497                                 return (1);
 498                         else
 499                                 return (0);
 500                 }
 501         }
 502         return (1);
 503 }