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 #include "privsep.h"
  47
  48 #include <sys/ioctl.h>
  49
  50 #include <net/if_media.h>
  51 #include <ifaddrs.h>
  52 #include <poll.h>
  53
  54 struct protocol *protocols;
  55 struct timeout *timeouts;
  56 static struct timeout *free_timeouts;
  57 static int interfaces_invalidated;
  58 void (*bootp_packet_handler)(struct interface_info *,
  59     struct dhcp_packet *, int, unsigned int,
  60     struct iaddr, struct hardware *);
  61
  62 static int interface_status(struct interface_info *ifinfo);
  63
  64 /*
  65  * Use getifaddrs() to get a list of all the attached interfaces.  For
  66  * each interface that's of type INET and not the loopback interface,
  67  * register that interface with the network I/O software, figure out
  68  * what subnet it's on, and add it to the list of interfaces.
  69  */
  70 void
  71 discover_interfaces(struct interface_info *iface)
  72 {
  73         struct ifaddrs *ifap, *ifa;
  74         struct sockaddr_in foo;
  75         struct ifreq *tif;
  76
  77         if (getifaddrs(&ifap) != 0)
  78                 error("getifaddrs failed");
  79
  80         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
  81                 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
  82                     (ifa->ifa_flags & IFF_POINTOPOINT) ||
  83                     (!(ifa->ifa_flags & IFF_UP)))
  84                         continue;
  85
  86                 if (strcmp(iface->name, ifa->ifa_name))
  87                         continue;
  88
  89                 /*
  90                  * If we have the capability, extract link information
  91                  * and record it in a linked list.
  92                  */
  93                 if (ifa->ifa_addr->sa_family == AF_LINK) {
  94                         struct sockaddr_dl *foo =
  95                             (struct sockaddr_dl *)ifa->ifa_addr;
  96
  97                         iface->index = foo->sdl_index;
  98                         iface->hw_address.hlen = foo->sdl_alen;
  99                         iface->hw_address.htype = HTYPE_ETHER; /* XXX */
 100                         memcpy(iface->hw_address.haddr,
 101                             LLADDR(foo), foo->sdl_alen);
 102                 } else if (ifa->ifa_addr->sa_family == AF_INET) {
 103                         struct iaddr addr;
 104
 105                         memcpy(&foo, ifa->ifa_addr, sizeof(foo));
 106                         if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
 107                                 continue;
 108                         if (!iface->ifp) {
 109                                 if ((tif = calloc(1, sizeof(struct ifreq)))
 110                                     == NULL)
 111                                         error("no space to remember ifp");
 112                                 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
 113                                 memcpy(&tif->ifr_addr, ifa->ifa_addr,
 114                                     ifa->ifa_addr->sa_len);
 115                                 iface->ifp = tif;
 116                                 iface->primary_address = foo.sin_addr;
 117                         }
 118                         addr.len = 4;
 119                         memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
 120                 }
 121         }
 122
 123         if (!iface->ifp)
 124                 error("%s: not found", iface->name);
 125
 126         /* Register the interface... */
 127         if_register_receive(iface);
 128         if_register_send(iface);
 129         add_protocol(iface->name, iface->rfdesc, got_one, iface);
 130         freeifaddrs(ifap);
 131 }
 132
 133 void
 134 reinitialize_interfaces(void)
 135 {
 136         interfaces_invalidated = 1;
 137 }
 138
 139 /*
 140  * Wait for packets to come in using poll().  When a packet comes in,
 141  * call receive_packet to receive the packet and possibly strip hardware
 142  * addressing information from it, and then call through the
 143  * bootp_packet_handler hook to try to do something with it.
 144  */
 145 void
 146 dispatch(void)
 147 {
 148         int count, live_interfaces, i, to_msec, nfds = 0;
 149         struct protocol *l;
 150         struct pollfd *fds;
 151         time_t howlong;
 152
 153         for (l = protocols; l; l = l->next)
 154                 nfds++;
 155
 156         fds = malloc(nfds * sizeof(struct pollfd));
 157         if (fds == NULL)
 158                 error("Can't allocate poll structures.");
 159
 160         do {
 161                 /*
 162                  * Call any expired timeouts, and then if there's still
 163                  * a timeout registered, time out the select call then.
 164                  */
 165 another:
 166                 if (timeouts) {
 167                         struct timeout *t;
 168
 169                         if (timeouts->when <= cur_time) {
 170                                 t = timeouts;
 171                                 timeouts = timeouts->next;
 172                                 (*(t->func))(t->what);
 173                                 t->next = free_timeouts;
 174                                 free_timeouts = t;
 175                                 goto another;
 176                         }
 177
 178                         /*
 179                          * Figure timeout in milliseconds, and check for
 180                          * potential overflow, so we can cram into an
 181                          * int for poll, while not polling with a
 182                          * negative timeout and blocking indefinitely.
 183                          */
 184                         howlong = timeouts->when - cur_time;
 185                         if (howlong > INT_MAX / 1000)
 186                                 howlong = INT_MAX / 1000;
 187                         to_msec = howlong * 1000;
 188                 } else
 189                         to_msec = -1;
 190
 191                 /* Set up the descriptors to be polled. */
 192                 live_interfaces = 0;
 193                 for (i = 0, l = protocols; l; l = l->next) {
 194                         struct interface_info *ip = l->local;
 195
 196                         if (ip == NULL || ip->dead)
 197                                 continue;
 198                         fds[i].fd = l->fd;
 199                         fds[i].events = POLLIN;
 200                         fds[i].revents = 0;
 201                         i++;
 202                         if (l->handler == got_one)
 203                                 live_interfaces++;
 204                 }
 205                 if (live_interfaces == 0)
 206                         error("No live interfaces to poll on - exiting.");
 207
 208                 /* Wait for a packet or a timeout... XXX */
 209                 count = poll(fds, nfds, to_msec);
 210
 211                 /* Not likely to be transitory... */
 212                 if (count == -1) {
 213                         if (errno == EAGAIN || errno == EINTR) {
 214                                 time(&cur_time);
 215                                 continue;
 216                         } else
 217                                 error("poll: %m");
 218                 }
 219
 220                 /* Get the current time... */
 221                 time(&cur_time);
 222
 223                 i = 0;
 224                 for (l = protocols; l; l = l->next) {
 225                         struct interface_info *ip;
 226                         ip = l->local;
 227                         if ((fds[i].revents & (POLLIN | POLLHUP))) {
 228                                 fds[i].revents = 0;
 229                                 if (ip && (l->handler != got_one ||
 230                                     !ip->dead))
 231                                         (*(l->handler))(l);
 232                                 if (interfaces_invalidated)
 233                                         break;
 234                         }
 235                         i++;
 236                 }
 237                 interfaces_invalidated = 0;
 238         } while (1);
 239 }
 240
 241
 242 void
 243 got_one(struct protocol *l)
 244 {
 245         struct sockaddr_in from;
 246         struct hardware hfrom;
 247         struct iaddr ifrom;
 248         ssize_t result;
 249         union {
 250                 /*
 251                  * Packet input buffer.  Must be as large as largest
 252                  * possible MTU.
 253                  */
 254                 unsigned char packbuf[4095];
 255                 struct dhcp_packet packet;
 256         } u;
 257         struct interface_info *ip = l->local;
 258
 259         if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
 260             &hfrom)) == -1) {
 261                 warning("receive_packet failed on %s: %s", ip->name,
 262                     strerror(errno));
 263                 ip->errors++;
 264                 if ((!interface_status(ip)) ||
 265                     (ip->noifmedia && ip->errors > 20)) {
 266                         /* our interface has gone away. */
 267                         warning("Interface %s no longer appears valid.",
 268                             ip->name);
 269                         ip->dead = 1;
 270                         interfaces_invalidated = 1;
 271                         close(l->fd);
 272                         remove_protocol(l);
 273                         free(ip);
 274                 }
 275                 return;
 276         }
 277         if (result == 0)
 278                 return;
 279
 280         if (bootp_packet_handler) {
 281                 ifrom.len = 4;
 282                 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
 283
 284                 (*bootp_packet_handler)(ip, &u.packet, result,
 285                     from.sin_port, ifrom, &hfrom);
 286         }
 287 }
 288
 289 int
 290 interface_status(struct interface_info *ifinfo)
 291 {
 292         char *ifname = ifinfo->name;
 293         int ifsock = ifinfo->rfdesc;
 294         struct ifreq ifr;
 295         struct ifmediareq ifmr;
 296
 297         /* get interface flags */
 298         memset(&ifr, 0, sizeof(ifr));
 299         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 300         if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
 301                 syslog(LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m", ifname);
 302                 goto inactive;
 303         }
 304
 305         /*
 306          * if one of UP and RUNNING flags is dropped,
 307          * the interface is not active.
 308          */
 309         if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
 310                 goto inactive;
 311
 312         /* Next, check carrier on the interface, if possible */
 313         if (ifinfo->noifmedia)
 314                 goto active;
 315         memset(&ifmr, 0, sizeof(ifmr));
 316         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 317         if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
 318                 if (errno != EINVAL) {
 319                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 320                             ifname);
 321
 322                         ifinfo->noifmedia = 1;
 323                         goto active;
 324                 }
 325                 /*
 326                  * EINVAL (or ENOTTY) simply means that the interface
 327                  * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
 328                  */
 329                 ifinfo->noifmedia = 1;
 330                 goto active;
 331         }
 332         if (ifmr.ifm_status & IFM_AVALID) {
 333                 switch (ifmr.ifm_active & IFM_NMASK) {
 334                 case IFM_ETHER:
 335                 case IFM_IEEE80211:
 336                         if (ifmr.ifm_status & IFM_ACTIVE)
 337                                 goto active;
 338                         else
 339                                 goto inactive;
 340                         break;
 341                 default:
 342                         goto inactive;
 343                 }
 344         }
 345 inactive:
 346         return (0);
 347 active:
 348         return (1);
 349 }
 350
 351 void
 352 add_timeout(time_t when, void (*where)(void *), void *what)
 353 {
 354         struct timeout *t, *q;
 355
 356         /* See if this timeout supersedes an existing timeout. */
 357         t = NULL;
 358         for (q = timeouts; q; q = q->next) {
 359                 if (q->func == where && q->what == what) {
 360                         if (t)
 361                                 t->next = q->next;
 362                         else
 363                                 timeouts = q->next;
 364                         break;
 365                 }
 366                 t = q;
 367         }
 368
 369         /* If we didn't supersede a timeout, allocate a timeout
 370            structure now. */
 371         if (!q) {
 372                 if (free_timeouts) {
 373                         q = free_timeouts;
 374                         free_timeouts = q->next;
 375                         q->func = where;
 376                         q->what = what;
 377                 } else {
 378                         q = malloc(sizeof(struct timeout));
 379                         if (!q)
 380                                 error("Can't allocate timeout structure!");
 381                         q->func = where;
 382                         q->what = what;
 383                 }
 384         }
 385
 386         q->when = when;
 387
 388         /* Now sort this timeout into the timeout list. */
 389
 390         /* Beginning of list? */
 391         if (!timeouts || timeouts->when > q->when) {
 392                 q->next = timeouts;
 393                 timeouts = q;
 394                 return;
 395         }
 396
 397         /* Middle of list? */
 398         for (t = timeouts; t->next; t = t->next) {
 399                 if (t->next->when > q->when) {
 400                         q->next = t->next;
 401                         t->next = q;
 402                         return;
 403                 }
 404         }
 405
 406         /* End of list. */
 407         t->next = q;
 408         q->next = NULL;
 409 }
 410
 411 void
 412 cancel_timeout(void (*where)(void *), void *what)
 413 {
 414         struct timeout *t, *q;
 415
 416         /* Look for this timeout on the list, and unlink it if we find it. */
 417         t = NULL;
 418         for (q = timeouts; q; q = q->next) {
 419                 if (q->func == where && q->what == what) {
 420                         if (t)
 421                                 t->next = q->next;
 422                         else
 423                                 timeouts = q->next;
 424                         break;
 425                 }
 426                 t = q;
 427         }
 428
 429         /* If we found the timeout, put it on the free list. */
 430         if (q) {
 431                 q->next = free_timeouts;
 432                 free_timeouts = q;
 433         }
 434 }
 435
 436 /* Add a protocol to the list of protocols... */
 437 void
 438 add_protocol(char *name, int fd, void (*handler)(struct protocol *),
 439     void *local)
 440 {
 441         struct protocol *p;
 442
 443         p = malloc(sizeof(*p));
 444         if (!p)
 445                 error("can't allocate protocol struct for %s", name);
 446
 447         p->fd = fd;
 448         p->handler = handler;
 449         p->local = local;
 450         p->next = protocols;
 451         protocols = p;
 452 }
 453
 454 void
 455 remove_protocol(struct protocol *proto)
 456 {
 457         struct protocol *p, *next;
 458
 459         for (p = protocols; p; p = next) {
 460                 next = p->next;
 461                 if (p == proto) {
 462                         protocols = p->next;
 463                         free(p);
 464                 }
 465         }
 466 }
 467
 468 int
 469 interface_link_status(char *ifname)
 470 {
 471         struct ifmediareq ifmr;
 472         int sock;
 473
 474         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 475                 error("Can't create socket");
 476
 477         memset(&ifmr, 0, sizeof(ifmr));
 478         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 479         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
 480                 /* EINVAL -> link state unknown. treat as active */
 481                 if (errno != EINVAL)
 482                         syslog(LOG_DEBUG, "ioctl(SIOCGIFMEDIA) on %s: %m",
 483                             ifname);
 484                 close(sock);
 485                 return (1);
 486         }
 487         close(sock);
 488
 489         if (ifmr.ifm_status & IFM_AVALID) {
 490                 switch (ifmr.ifm_active & IFM_NMASK) {
 491                 case IFM_ETHER:
 492                 case IFM_IEEE80211:
 493                         if (ifmr.ifm_status & IFM_ACTIVE)
 494                                 return (1);
 495                         else
 496                                 return (0);
 497                 }
 498         }
 499         return (1);
 500 }
 501
 502 void
 503 interface_set_mtu_unpriv(int privfd, u_int16_t mtu)
 504 {
 505         struct imsg_hdr hdr;
 506         struct buf *buf;
 507         int errs = 0;
 508
 509         hdr.code = IMSG_SET_INTERFACE_MTU;
 510         hdr.len = sizeof(hdr) +
 511                 sizeof(u_int16_t);
 512
 513         if ((buf = buf_open(hdr.len)) == NULL)
 514                 error("buf_open: %m");
 515
 516         errs += buf_add(buf, &hdr, sizeof(hdr));
 517         errs += buf_add(buf, &mtu, sizeof(mtu));
 518         if (errs)
 519                 error("buf_add: %m");
 520
 521         if (buf_close(privfd, buf) == -1)
 522                 error("buf_close: %m");
 523 }
 524
 525 void
 526 interface_set_mtu_priv(char *ifname, u_int16_t mtu)
 527 {
 528         struct ifreq ifr;
 529         int sock;
 530
 531         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 532                 error("Can't create socket");
 533
 534         memset(&ifr, 0, sizeof(ifr));
 535
 536         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 537         ifr.ifr_mtu = mtu;
 538
 539         if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
 540                 warning("SIOCSIFMTU failed (%d): %s", mtu,
 541                         strerror(errno));
 542         close(sock);
 543 }