sbin/dhclient/dispatch.c

   1 /*      $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $     */
   2
   3 /*-
   4  * SPDX-License-Identifier: BSD-3-Clause
   5  *
   6  * Copyright 2004 Henning Brauer <henning@openbsd.org>
   7  * Copyright (c) 1995, 1996, 1997, 1998, 1999
   8  * The Internet Software Consortium.   All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of The Internet Software Consortium nor the names
  20  *    of its contributors may be used to endorse or promote products derived
  21  *    from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
  24  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  25  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  26  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
  28  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  31  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  32  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  33  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  34  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  * This software has been written for the Internet Software Consortium
  38  * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
  39  * Enterprises.  To learn more about the Internet Software Consortium,
  40  * see ``http://www.vix.com/isc''.  To learn more about Vixie
  41  * Enterprises, see ``http://www.vix.com''.
  42  */
  43
  44 #include <sys/cdefs.h>
  45 __FBSDID("$FreeBSD$");
  46
  47 #include "dhcpd.h"
  48 #include "privsep.h"
  49
  50 #include <sys/ioctl.h>
  51
  52 #include <net/if_media.h>
  53 #include <ifaddrs.h>
  54 #include <poll.h>
  55
  56 struct protocol *protocols;
  57 struct timeout *timeouts;
  58 static struct timeout *free_timeouts;
  59 static int interfaces_invalidated;
  60 void (*bootp_packet_handler)(struct interface_info *,
  61     struct dhcp_packet *, int, unsigned int,
  62     struct iaddr, struct hardware *);
  63
  64 static int interface_status(struct interface_info *ifinfo);
  65
  66 /*
  67  * Use getifaddrs() to get a list of all the attached interfaces.  For
  68  * each interface that's of type INET and not the loopback interface,
  69  * register that interface with the network I/O software, figure out
  70  * what subnet it's on, and add it to the list of interfaces.
  71  */
  72 void
  73 discover_interfaces(struct interface_info *iface)
  74 {
  75         struct ifaddrs *ifap, *ifa;
  76         struct sockaddr_in foo;
  77         struct ifreq *tif;
  78
  79         if (getifaddrs(&ifap) != 0)
  80                 error("getifaddrs failed");
  81
  82         for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
  83                 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
  84                     (ifa->ifa_flags & IFF_POINTOPOINT) ||
  85                     (!(ifa->ifa_flags & IFF_UP)))
  86                         continue;
  87
  88                 if (strcmp(iface->name, ifa->ifa_name))
  89                         continue;
  90
  91                 /*
  92                  * If we have the capability, extract link information
  93                  * and record it in a linked list.
  94                  */
  95                 if (ifa->ifa_addr->sa_family == AF_LINK) {
  96                         struct sockaddr_dl *foo =
  97                             (struct sockaddr_dl *)ifa->ifa_addr;
  98
  99                         iface->index = foo->sdl_index;
 100                         iface->hw_address.hlen = foo->sdl_alen;
 101                         iface->hw_address.htype = HTYPE_ETHER; /* XXX */
 102                         memcpy(iface->hw_address.haddr,
 103                             LLADDR(foo), foo->sdl_alen);
 104                 } else if (ifa->ifa_addr->sa_family == AF_INET) {
 105                         struct iaddr addr;
 106
 107                         memcpy(&foo, ifa->ifa_addr, sizeof(foo));
 108                         if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
 109                                 continue;
 110                         if (!iface->ifp) {
 111                                 if ((tif = calloc(1, sizeof(struct ifreq)))
 112                                     == NULL)
 113                                         error("no space to remember ifp");
 114                                 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
 115                                 memcpy(&tif->ifr_addr, ifa->ifa_addr,
 116                                     ifa->ifa_addr->sa_len);
 117                                 iface->ifp = tif;
 118                                 iface->primary_address = foo.sin_addr;
 119                         }
 120                         addr.len = 4;
 121                         memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
 122                 }
 123         }
 124
 125         if (!iface->ifp)
 126                 error("%s: not found", iface->name);
 127
 128         /* Register the interface... */
 129         if_register_receive(iface);
 130         if_register_send(iface);
 131         add_protocol(iface->name, iface->rfdesc, got_one, iface);
 132         freeifaddrs(ifap);
 133 }
 134
 135 void
 136 reinitialize_interfaces(void)
 137 {
 138         interfaces_invalidated = 1;
 139 }
 140
 141 /*
 142  * Wait for packets to come in using poll().  When a packet comes in,
 143  * call receive_packet to receive the packet and possibly strip hardware
 144  * addressing information from it, and then call through the
 145  * bootp_packet_handler hook to try to do something with it.
 146  */
 147 void
 148 dispatch(void)
 149 {
 150         int count, live_interfaces, i, to_msec, nfds = 0;
 151         struct protocol *l;
 152         struct pollfd *fds;
 153         time_t howlong;
 154
 155         for (l = protocols; l; l = l->next)
 156                 nfds++;
 157
 158         fds = malloc(nfds * sizeof(struct pollfd));
 159         if (fds == NULL)
 160                 error("Can't allocate poll structures.");
 161
 162         do {
 163                 /*
 164                  * Call any expired timeouts, and then if there's still
 165                  * a timeout registered, time out the select call then.
 166                  */
 167 another:
 168                 if (timeouts) {
 169                         struct timeout *t;
 170
 171                         if (timeouts->when <= cur_time) {
 172                                 t = timeouts;
 173                                 timeouts = timeouts->next;
 174                                 (*(t->func))(t->what);
 175                                 t->next = free_timeouts;
 176                                 free_timeouts = t;
 177                                 goto another;
 178                         }
 179
 180                         /*
 181                          * Figure timeout in milliseconds, and check for
 182                          * potential overflow, so we can cram into an
 183                          * int for poll, while not polling with a
 184                          * negative timeout and blocking indefinitely.
 185                          */
 186                         howlong = timeouts->when - cur_time;
 187                         if (howlong > INT_MAX / 1000)
 188                                 howlong = INT_MAX / 1000;
 189                         to_msec = howlong * 1000;
 190                 } else
 191                         to_msec = -1;
 192
 193                 /* Set up the descriptors to be polled. */
 194                 live_interfaces = 0;
 195                 for (i = 0, l = protocols; l; l = l->next) {
 196                         struct interface_info *ip = l->local;
 197
 198                         if (ip == NULL || ip->dead)
 199                                 continue;
 200                         fds[i].fd = l->fd;
 201                         fds[i].events = POLLIN;
 202                         fds[i].revents = 0;
 203                         i++;
 204                         if (l->handler == got_one)
 205                                 live_interfaces++;
 206                 }
 207                 if (live_interfaces == 0)
 208                         error("No live interfaces to poll on - exiting.");
 209
 210                 /* Wait for a packet or a timeout... XXX */
 211                 count = poll(fds, nfds, to_msec);
 212
 213                 /* Not likely to be transitory... */
 214                 if (count == -1) {
 215                         if (errno == EAGAIN || errno == EINTR) {
 216                                 time(&cur_time);
 217                                 continue;
 218                         } else
 219                                 error("poll: %m");
 220                 }
 221
 222                 /* Get the current time... */
 223                 time(&cur_time);
 224
 225                 i = 0;
 226                 for (l = protocols; l; l = l->next) {
 227                         struct interface_info *ip;
 228                         ip = l->local;
 229                         if ((fds[i].revents & (POLLIN | POLLHUP))) {
 230                                 fds[i].revents = 0;
 231                                 if (ip && (l->handler != got_one ||
 232                                     !ip->dead))
 233                                         (*(l->handler))(l);
 234                                 if (interfaces_invalidated)
 235                                         break;
 236                         }
 237                         i++;
 238                 }
 239                 interfaces_invalidated = 0;
 240         } while (1);
 241 }
 242
 243
 244 void
 245 got_one(struct protocol *l)
 246 {
 247         struct sockaddr_in from;
 248         struct hardware hfrom;
 249         struct iaddr ifrom;
 250         ssize_t result;
 251         union {
 252                 /*
 253                  * Packet input buffer.  Must be as large as largest
 254                  * possible MTU.
 255                  */
 256                 unsigned char packbuf[4095];
 257                 struct dhcp_packet packet;
 258         } u;
 259         struct interface_info *ip = l->local;
 260
 261         if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
 262             &hfrom)) == -1) {
 263                 warning("receive_packet failed on %s: %s", ip->name,
 264                     strerror(errno));
 265                 ip->errors++;
 266                 if ((!interface_status(ip)) ||
 267                     (ip->noifmedia && ip->errors > 20)) {
 268                         /* our interface has gone away. */
 269                         warning("Interface %s no longer appears valid.",
 270                             ip->name);
 271                         ip->dead = 1;
 272                         interfaces_invalidated = 1;
 273                         close(l->fd);
 274                         remove_protocol(l);
 275                         free(ip);
 276                 }
 277                 return;
 278         }
 279         if (result == 0)
 280                 return;
 281
 282         if (bootp_packet_handler) {
 283                 ifrom.len = 4;
 284                 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
 285
 286                 (*bootp_packet_handler)(ip, &u.packet, result,
 287                     from.sin_port, ifrom, &hfrom);
 288         }
 289 }
 290
 291 int
 292 interface_status(struct interface_info *ifinfo)
 293 {
 294         char *ifname = ifinfo->name;
 295         int ifsock = ifinfo->rfdesc;
 296         struct ifreq ifr;
 297         struct ifmediareq ifmr;
 298
 299         /* get interface flags */
 300         memset(&ifr, 0, sizeof(ifr));
 301         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 302         if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
 303                 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m",
 304                     ifname);
 305                 goto inactive;
 306         }
 307
 308         /*
 309          * if one of UP and RUNNING flags is dropped,
 310          * the interface is not active.
 311          */
 312         if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
 313                 goto inactive;
 314
 315         /* Next, check carrier on the interface, if possible */
 316         if (ifinfo->noifmedia)
 317                 goto active;
 318         memset(&ifmr, 0, sizeof(ifmr));
 319         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 320         if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
 321                 if (errno != EINVAL) {
 322                         cap_syslog(capsyslog, LOG_DEBUG,
 323                             "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
 324                         ifinfo->noifmedia = 1;
 325                         goto active;
 326                 }
 327                 /*
 328                  * EINVAL (or ENOTTY) simply means that the interface
 329                  * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
 330                  */
 331                 ifinfo->noifmedia = 1;
 332                 goto active;
 333         }
 334         if (ifmr.ifm_status & IFM_AVALID) {
 335                 switch (ifmr.ifm_active & IFM_NMASK) {
 336                 case IFM_ETHER:
 337                 case IFM_IEEE80211:
 338                         if (ifmr.ifm_status & IFM_ACTIVE)
 339                                 goto active;
 340                         else
 341                                 goto inactive;
 342                         break;
 343                 default:
 344                         goto inactive;
 345                 }
 346         }
 347 inactive:
 348         return (0);
 349 active:
 350         return (1);
 351 }
 352
 353 void
 354 add_timeout(time_t when, void (*where)(void *), void *what)
 355 {
 356         struct timeout *t, *q;
 357
 358         /* See if this timeout supersedes an existing timeout. */
 359         t = NULL;
 360         for (q = timeouts; q; q = q->next) {
 361                 if (q->func == where && q->what == what) {
 362                         if (t)
 363                                 t->next = q->next;
 364                         else
 365                                 timeouts = q->next;
 366                         break;
 367                 }
 368                 t = q;
 369         }
 370
 371         /* If we didn't supersede a timeout, allocate a timeout
 372            structure now. */
 373         if (!q) {
 374                 if (free_timeouts) {
 375                         q = free_timeouts;
 376                         free_timeouts = q->next;
 377                         q->func = where;
 378                         q->what = what;
 379                 } else {
 380                         q = malloc(sizeof(struct timeout));
 381                         if (!q)
 382                                 error("Can't allocate timeout structure!");
 383                         q->func = where;
 384                         q->what = what;
 385                 }
 386         }
 387
 388         q->when = when;
 389
 390         /* Now sort this timeout into the timeout list. */
 391
 392         /* Beginning of list? */
 393         if (!timeouts || timeouts->when > q->when) {
 394                 q->next = timeouts;
 395                 timeouts = q;
 396                 return;
 397         }
 398
 399         /* Middle of list? */
 400         for (t = timeouts; t->next; t = t->next) {
 401                 if (t->next->when > q->when) {
 402                         q->next = t->next;
 403                         t->next = q;
 404                         return;
 405                 }
 406         }
 407
 408         /* End of list. */
 409         t->next = q;
 410         q->next = NULL;
 411 }
 412
 413 void
 414 cancel_timeout(void (*where)(void *), void *what)
 415 {
 416         struct timeout *t, *q;
 417
 418         /* Look for this timeout on the list, and unlink it if we find it. */
 419         t = NULL;
 420         for (q = timeouts; q; q = q->next) {
 421                 if (q->func == where && q->what == what) {
 422                         if (t)
 423                                 t->next = q->next;
 424                         else
 425                                 timeouts = q->next;
 426                         break;
 427                 }
 428                 t = q;
 429         }
 430
 431         /* If we found the timeout, put it on the free list. */
 432         if (q) {
 433                 q->next = free_timeouts;
 434                 free_timeouts = q;
 435         }
 436 }
 437
 438 /* Add a protocol to the list of protocols... */
 439 void
 440 add_protocol(char *name, int fd, void (*handler)(struct protocol *),
 441     void *local)
 442 {
 443         struct protocol *p;
 444
 445         p = malloc(sizeof(*p));
 446         if (!p)
 447                 error("can't allocate protocol struct for %s", name);
 448
 449         p->fd = fd;
 450         p->handler = handler;
 451         p->local = local;
 452         p->next = protocols;
 453         protocols = p;
 454 }
 455
 456 void
 457 remove_protocol(struct protocol *proto)
 458 {
 459         struct protocol *p, *next;
 460
 461         for (p = protocols; p; p = next) {
 462                 next = p->next;
 463                 if (p == proto) {
 464                         protocols = p->next;
 465                         free(p);
 466                 }
 467         }
 468 }
 469
 470 int
 471 interface_link_status(char *ifname)
 472 {
 473         struct ifmediareq ifmr;
 474         int sock;
 475
 476         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 477                 error("Can't create socket");
 478
 479         memset(&ifmr, 0, sizeof(ifmr));
 480         strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
 481         if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
 482                 /* EINVAL -> link state unknown. treat as active */
 483                 if (errno != EINVAL)
 484                         cap_syslog(capsyslog, LOG_DEBUG,
 485                             "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
 486                 close(sock);
 487                 return (1);
 488         }
 489         close(sock);
 490
 491         if (ifmr.ifm_status & IFM_AVALID) {
 492                 switch (ifmr.ifm_active & IFM_NMASK) {
 493                 case IFM_ETHER:
 494                 case IFM_IEEE80211:
 495                         if (ifmr.ifm_status & IFM_ACTIVE)
 496                                 return (1);
 497                         else
 498                                 return (0);
 499                 }
 500         }
 501         return (1);
 502 }
 503
 504 void
 505 interface_set_mtu_unpriv(int privfd, u_int16_t mtu)
 506 {
 507         struct imsg_hdr hdr;
 508         struct buf *buf;
 509         int errs = 0;
 510
 511         hdr.code = IMSG_SET_INTERFACE_MTU;
 512         hdr.len = sizeof(hdr) +
 513                 sizeof(u_int16_t);
 514
 515         if ((buf = buf_open(hdr.len)) == NULL)
 516                 error("buf_open: %m");
 517
 518         errs += buf_add(buf, &hdr, sizeof(hdr));
 519         errs += buf_add(buf, &mtu, sizeof(mtu));
 520         if (errs)
 521                 error("buf_add: %m");
 522
 523         if (buf_close(privfd, buf) == -1)
 524                 error("buf_close: %m");
 525 }
 526
 527 void
 528 interface_set_mtu_priv(char *ifname, u_int16_t mtu)
 529 {
 530         struct ifreq ifr;
 531         int sock;
 532
 533         if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 534                 error("Can't create socket");
 535
 536         memset(&ifr, 0, sizeof(ifr));
 537
 538         strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 539         ifr.ifr_mtu = mtu;
 540
 541         if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
 542                 warning("SIOCSIFMTU failed (%d): %s", mtu,
 543                         strerror(errno));
 544         close(sock);
 545 }