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 "dhcpd.h"
  43
  44 #include <sys/ioctl.h>
  45
  46 #include <net/if_media.h>
  47 #include <ifaddrs.h>
  48 #include <poll.h>
  49
  50 struct protocol *protocols;
  51 struct timeout *timeouts;
  52 static struct timeout *free_timeouts;
  53 static int interfaces_invalidated;
  54 void (*bootp_packet_handler)(struct interface_info *,
  55     struct dhcp_packet *, int, unsigned int,
  56     struct iaddr, struct hardware *);
  57
  58 static int interface_status(struct interface_info *ifinfo);
  59
  60 /*
  61  * Use getifaddrs() to get a list of all the attached interfaces.  For
  62  * each interface that's of type INET and not the loopback interface,
  63  * register that interface with the network I/O software, figure out
  64  * what subnet it's on, and add it to the list of interfaces.
  65  */
  66 void
  67 discover_interfaces(struct interface_info *iface)
  68 {
  69         struct ifaddrs *ifap, *ifa;
  70         struct sockaddr_in foo;
  71         struct ifreq *tif;
  72
  73         if (getifaddrs(&ifap) != 0)
  74                 error("getifaddrs failed");
  75
  76         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
  77                 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
  78                     (ifa->ifa_flags & IFF_POINTOPOINT) ||
  79                     (!(ifa->ifa_flags & IFF_UP)))
  80                         continue;
  81
  82                 if (strcmp(iface->name, ifa->ifa_name))
  83                         continue;
  84
  85                 /*
  86                  * If we have the capability, extract link information
  87                  * and record it in a linked list.
  88                  */
  89                 if (ifa->ifa_addr->sa_family == AF_LINK) {
  90                         struct sockaddr_dl *foo =
  91                             (struct sockaddr_dl *)ifa->ifa_addr;
  92
  93                         iface->index = foo->sdl_index;
  94                         iface->hw_address.hlen = foo->sdl_alen;
  95                         iface->hw_address.htype = HTYPE_ETHER; /* XXX */
  96                         memcpy(iface->hw_address.haddr,
  97                             LLADDR(foo), foo->sdl_alen);
  98                 } else if (ifa->ifa_addr->sa_family == AF_INET) {
  99                         struct iaddr addr;
 100
 101                         memcpy(&foo, ifa->ifa_addr, sizeof(foo));
 102                         if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
 103                                 continue;
 104                         if (!iface->ifp) {
 105                                 int len = IFNAMSIZ + ifa->ifa_addr->sa_len;
 106                                 if ((tif = malloc(len)) == NULL)
 107                                         error("no space to remember ifp");
 108                                 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
 109                                 memcpy(&tif->ifr_addr, ifa->ifa_addr,
 110                                     ifa->ifa_addr->sa_len);
 111                                 iface->ifp = tif;
 112                                 iface->primary_address = foo.sin_addr;
 113                         }
 114                         addr.len = 4;
 115                         memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
 116                 }
 117         }
 118
 119         if (!iface->ifp)
 120                 error("%s: not found", iface->name);
 121
 122         /* Register the interface... */
 123         if_register_receive(iface);
 124         if_register_send(iface);
 125         add_protocol(iface->name, iface->rfdesc, got_one, iface);
 126         freeifaddrs(ifap);
 127 }
 128
 129 void
 130 reinitialize_interfaces(void)
 131 {
 132         interfaces_invalidated = 1;
 133 }
 134
 135 /*
 136  * Wait for packets to come in using poll().  When a packet comes in,
 137  * call receive_packet to receive the packet and possibly strip hardware
 138  * addressing information from it, and then call through the
 139  * bootp_packet_handler hook to try to do something with it.
 140  */
 141 void
 142 dispatch(void)
 143 {
 144         int count, i, to_msec, nfds = 0;
 145         struct protocol *l;
 146         struct pollfd *fds;
 147         time_t howlong;
 148
 149         for (l = protocols; l; l = l->next)
 150                 nfds++;
 151
 152         fds = malloc(nfds * sizeof(struct pollfd));
 153         if (fds == NULL)
 154                 error("Can't allocate poll structures.");
 155
 156         do {
 157                 /*
 158                  * Call any expired timeouts, and then if there's still
 159                  * a timeout registered, time out the select call then.
 160                  */
 161 another:
 162                 if (timeouts) {
 163                         struct timeout *t;
 164
 165                         if (timeouts->when <= cur_time) {
 166                                 t = timeouts;
 167                                 timeouts = timeouts->next;
 168                                 (*(t->func))(t->what);
 169                                 t->next = free_timeouts;
 170                                 free_timeouts = t;
 171                                 goto another;
 172                         }
 173
 174                         /*
 175                          * Figure timeout in milliseconds, and check for
 176                          * potential overflow, so we can cram into an
 177                          * int for poll, while not polling with a
 178                          * negative timeout and blocking indefinitely.
 179                          */
 180                         howlong = timeouts->when - cur_time;
 181                         if (howlong > INT_MAX / 1000)
 182                                 howlong = INT_MAX / 1000;
 183                         to_msec = howlong * 1000;
 184                 } else
 185                         to_msec = -1;
 186
 187                 /* Set up the descriptors to be polled. */
 188                 for (i = 0, l = protocols; l; l = l->next) {
 189                         struct interface_info *ip = l->local;
 190
 191                         if (ip && (l->handler != got_one || !ip->dead)) {
 192                                 fds[i].fd = l->fd;
 193                                 fds[i].events = POLLIN;
 194                                 fds[i].revents = 0;
 195                                 i++;
 196                         }
 197                 }
 198
 199                 if (i == 0)
 200                         error("No live interfaces to poll on - exiting.");
 201
 202                 /* Wait for a packet or a timeout... XXX */
 203                 count = poll(fds, nfds, to_msec);
 204
 205                 /* Not likely to be transitory... */
 206                 if (count == -1) {
 207                         if (errno == EAGAIN || errno == EINTR) {
 208                                 time(&cur_time);
 209                                 continue;
 210                         } else
 211                                 error("poll: %m");
 212                 }
 213
 214                 /* Get the current time... */
 215                 time(&cur_time);
 216
 217                 i = 0;
 218                 for (l = protocols; l; l = l->next) {
 219                         struct interface_info *ip;
 220                         ip = l->local;
 221                         if ((fds[i].revents & (POLLIN | POLLHUP))) {
 222                                 fds[i].revents = 0;
 223                                 if (ip && (l->handler != got_one ||
 224                                     !ip->dead))
 225                                         (*(l->handler))(l);
 226                                 if (interfaces_invalidated)
 227                                         break;
 228                         }
 229                         i++;
 230                 }
 231                 interfaces_invalidated = 0;
 232         } while (1);
 233 }
 234
 235
 236 void
 237 got_one(struct protocol *l)
 238 {
 239         struct sockaddr_in from;
 240         struct hardware hfrom;
 241         struct iaddr ifrom;
 242         ssize_t result;
 243         union {
 244                 /*
 245                  * Packet input buffer.  Must be as large as largest
 246                  * possible MTU.
 247                  */
 248                 unsigned char packbuf[4095];
 249                 struct dhcp_packet packet;
 250         } u;
 251         struct interface_info *ip = l->local;
 252
 253         if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
 254             &hfrom)) == -1) {
 255                 warning("receive_packet failed on %s: %s", ip->name,
 256                     strerror(errno));
 257                 ip->errors++;
 258                 if ((!interface_status(ip)) ||
 259                     (ip->noifmedia && ip->errors > 20)) {
 260                         /* our interface has gone away. */
 261                         warning("Interface %s no longer appears valid.",
 262                             ip->name);
 263                         ip->dead = 1;
 264                         interfaces_invalidated = 1;
 265                         close(l->fd);
 266                         remove_protocol(l);
 267                         free(ip);
 268                 }
 269                 return;
 270         }
 271         if (result == 0)
 272                 return;
 273
 274         if (bootp_packet_handler) {
 275                 ifrom.len = 4;
 276                 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
 277
 278                 (*bootp_packet_handler)(ip, &u.packet, result,
 279                     from.sin_port, ifrom, &hfrom);
 280         }
 281 }
 282
 283 int
 284 interface_status(struct interface_info *ifinfo)
 285 {
 286         char *ifname = ifinfo->name;
 287         int ifsock = ifinfo->rfdesc;
 288         struct ifreq ifr;
 289         struct ifmediareq ifmr;
 290
 291         /* get interface flags */
 292         memset(&ifr, 0, sizeof(ifr));
 293         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 294         if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
 295                 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
 296                 goto inactive;
 297         }
 298
 299         /*
 300          * if one of UP and RUNNING flags is dropped,
 301          * the interface is not active.
 302          */
 303         if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
 304                 goto inactive;
 305
 306         /* Next, check carrier on the interface, if possible */
 307         if (ifinfo->noifmedia)
 308                 goto active;
 309         memset(&ifmr, 0, sizeof(ifmr));
 310         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 311         if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
 312                 if (errno != EINVAL) {
 313                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 314                             ifname);
 315
 316                         ifinfo->noifmedia = 1;
 317                         goto active;
 318                 }
 319                 /*
 320                  * EINVAL (or ENOTTY) simply means that the interface
 321                  * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
 322                  */
 323                 ifinfo->noifmedia = 1;
 324                 goto active;
 325         }
 326         if (ifmr.ifm_status & IFM_AVALID) {
 327                 switch (ifmr.ifm_active & IFM_NMASK) {
 328                 case IFM_ETHER:
 329                         if (ifmr.ifm_status & IFM_ACTIVE)
 330                                 goto active;
 331                         else
 332                                 goto inactive;
 333                         break;
 334                 default:
 335                         goto inactive;
 336                 }
 337         }
 338 inactive:
 339         return (0);
 340 active:
 341         return (1);
 342 }
 343
 344 void
 345 add_timeout(time_t when, void (*where)(void *), void *what)
 346 {
 347         struct timeout *t, *q;
 348
 349         /* See if this timeout supersedes an existing timeout. */
 350         t = NULL;
 351         for (q = timeouts; q; q = q->next) {
 352                 if (q->func == where && q->what == what) {
 353                         if (t)
 354                                 t->next = q->next;
 355                         else
 356                                 timeouts = q->next;
 357                         break;
 358                 }
 359                 t = q;
 360         }
 361
 362         /* If we didn't supersede a timeout, allocate a timeout
 363            structure now. */
 364         if (!q) {
 365                 if (free_timeouts) {
 366                         q = free_timeouts;
 367                         free_timeouts = q->next;
 368                         q->func = where;
 369                         q->what = what;
 370                 } else {
 371                         q = malloc(sizeof(struct timeout));
 372                         if (!q)
 373                                 error("Can't allocate timeout structure!");
 374                         q->func = where;
 375                         q->what = what;
 376                 }
 377         }
 378
 379         q->when = when;
 380
 381         /* Now sort this timeout into the timeout list. */
 382
 383         /* Beginning of list? */
 384         if (!timeouts || timeouts->when > q->when) {
 385                 q->next = timeouts;
 386                 timeouts = q;
 387                 return;
 388         }
 389
 390         /* Middle of list? */
 391         for (t = timeouts; t->next; t = t->next) {
 392                 if (t->next->when > q->when) {
 393                         q->next = t->next;
 394                         t->next = q;
 395                         return;
 396                 }
 397         }
 398
 399         /* End of list. */
 400         t->next = q;
 401         q->next = NULL;
 402 }
 403
 404 void
 405 cancel_timeout(void (*where)(void *), void *what)
 406 {
 407         struct timeout *t, *q;
 408
 409         /* Look for this timeout on the list, and unlink it if we find it. */
 410         t = NULL;
 411         for (q = timeouts; q; q = q->next) {
 412                 if (q->func == where && q->what == what) {
 413                         if (t)
 414                                 t->next = q->next;
 415                         else
 416                                 timeouts = q->next;
 417                         break;
 418                 }
 419                 t = q;
 420         }
 421
 422         /* If we found the timeout, put it on the free list. */
 423         if (q) {
 424                 q->next = free_timeouts;
 425                 free_timeouts = q;
 426         }
 427 }
 428
 429 /* Add a protocol to the list of protocols... */
 430 void
 431 add_protocol(char *name, int fd, void (*handler)(struct protocol *),
 432     void *local)
 433 {
 434         struct protocol *p;
 435
 436         p = malloc(sizeof(*p));
 437         if (!p)
 438                 error("can't allocate protocol struct for %s", name);
 439
 440         p->fd = fd;
 441         p->handler = handler;
 442         p->local = local;
 443         p->next = protocols;
 444         protocols = p;
 445 }
 446
 447 void
 448 remove_protocol(struct protocol *proto)
 449 {
 450         struct protocol *p, *next, *prev;
 451
 452         prev = NULL;
 453         for (p = protocols; p; p = next) {
 454                 next = p->next;
 455                 if (p == proto) {
 456                         if (prev)
 457                                 prev->next = p->next;
 458                         else
 459                                 protocols = p->next;
 460                         free(p);
 461                 }
 462         }
 463 }
 464
 465 int
 466 interface_link_status(char *ifname)
 467 {
 468         struct ifmediareq ifmr;
 469         int sock;
 470
 471         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 472                 error("Can't create socket");
 473
 474         memset(&ifmr, 0, sizeof(ifmr));
 475         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 476         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
 477                 /* EINVAL -> link state unknown. treat as active */
 478                 if (errno != EINVAL)
 479                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 480                             ifname);
 481                 close(sock);
 482                 return (1);
 483         }
 484         close(sock);
 485
 486         if (ifmr.ifm_status & IFM_AVALID) {
 487                 if ((ifmr.ifm_active & IFM_NMASK) == IFM_ETHER) {
 488                         if (ifmr.ifm_status & IFM_ACTIVE)
 489                                 return (1);
 490                         else
 491                                 return (0);
 492                 }
 493         }
 494         return (1);
 495 }