sbin/dhclient/dhclient.c

   1 /*      $OpenBSD: src/sbin/dhclient/dhclient.c,v 1.139 2011/04/04 11:14:52 krw 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  * This client was substantially modified and enhanced by Elliot Poger
  42  * for use on Linux while he was working on the MosquitoNet project at
  43  * Stanford.
  44  *
  45  * The current version owes much to Elliot's Linux enhancements, but
  46  * was substantially reorganized and partially rewritten by Ted Lemon
  47  * so as to use the same networking framework that the Internet Software
  48  * Consortium DHCP server uses.   Much system-specific configuration code
  49  * was moved into a shell script so that as support for more operating
  50  * systems is added, it will not be necessary to port and maintain
  51  * system-specific configuration code to these operating systems - instead,
  52  * the shell script can invoke the native tools to accomplish the same
  53  * purpose.
  54  */
  55 #include <sys/ioctl.h>
  56
  57 #include <ctype.h>
  58 #include <poll.h>
  59 #include <pwd.h>
  60 #include <unistd.h>
  61
  62 #include "dhcpd.h"
  63 #include "privsep.h"
  64
  65 #define CLIENT_PATH             "PATH=/usr/bin:/usr/sbin:/bin:/sbin"
  66 #define DEFAULT_LEASE_TIME      43200   /* 12 hours... */
  67 #define TIME_MAX                2147483647
  68 #define POLL_FAILURES           10
  69 #define POLL_FAILURE_WAIT       1       /* Back off multiplier (seconds) */
  70
  71 time_t cur_time;
  72
  73 char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
  74 char *path_dhclient_db = NULL;
  75
  76 int log_perror = 1;
  77 int privfd;
  78 int nullfd = -1;
  79 int no_daemon;
  80 int unknown_ok = 1;
  81 int routefd = -1;
  82
  83 struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
  84 struct in_addr inaddr_any;
  85 struct sockaddr_in sockaddr_broadcast;
  86
  87 struct interface_info *ifi;
  88 struct client_state *client;
  89 struct client_config *config;
  90
  91 int              findproto(char *, int);
  92 struct sockaddr *get_ifa(char *, int);
  93 void             usage(void);
  94 int              check_option(struct client_lease *l, int option);
  95 int              ipv4addrs(char * buf);
  96 int              res_hnok(const char *dn);
  97 char            *option_as_string(unsigned int code, unsigned char *data, int len);
  98 int              fork_privchld(int, int);
  99 void             get_ifname(char *, char *);
 100 #define ROUNDUP(a) \
 101             ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
 102 #define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
 103
 104 time_t  scripttime;
 105 static FILE *leaseFile;
 106
 107 int
 108 findproto(char *cp, int n)
 109 {
 110         struct sockaddr *sa;
 111         int i;
 112
 113         if (n == 0)
 114                 return -1;
 115         for (i = 1; i; i <<= 1) {
 116                 if (i & n) {
 117                         sa = (struct sockaddr *)cp;
 118                         switch (i) {
 119                         case RTA_IFA:
 120                         case RTA_DST:
 121                         case RTA_GATEWAY:
 122                         case RTA_NETMASK:
 123                                 if (sa->sa_family == AF_INET)
 124                                         return AF_INET;
 125                                 if (sa->sa_family == AF_INET6)
 126                                         return AF_INET6;
 127                                 break;
 128                         case RTA_IFP:
 129                                 break;
 130                         }
 131                         ADVANCE(cp, sa);
 132                 }
 133         }
 134         return (-1);
 135 }
 136
 137 struct sockaddr *
 138 get_ifa(char *cp, int n)
 139 {
 140         struct sockaddr *sa;
 141         int i;
 142
 143         if (n == 0)
 144                 return (NULL);
 145         for (i = 1; i; i <<= 1)
 146                 if (i & n) {
 147                         sa = (struct sockaddr *)cp;
 148                         if (i == RTA_IFA)
 149                                 return (sa);
 150                         ADVANCE(cp, sa);
 151                 }
 152
 153         return (NULL);
 154 }
 155 struct iaddr defaddr = { .len = 4 }; /* NULL is for silence warnings */
 156
 157 void
 158 routehandler(void)
 159 {
 160         int linkstat;
 161         char msg[2048];
 162         struct rt_msghdr *rtm;
 163         struct if_msghdr *ifm;
 164         struct ifa_msghdr *ifam;
 165         struct if_announcemsghdr *ifan;
 166         struct client_lease *l;
 167         time_t t = time(NULL);
 168         struct sockaddr *sa;
 169         struct iaddr a;
 170         ssize_t n;
 171         char *errmsg, buf[64];
 172
 173         do {
 174                 n = read(routefd, &msg, sizeof(msg));
 175         } while (n == -1 && errno == EINTR);
 176
 177         rtm = (struct rt_msghdr *)msg;
 178         if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen ||
 179             rtm->rtm_version != RTM_VERSION)
 180                 return;
 181
 182         switch (rtm->rtm_type) {
 183         case RTM_NEWADDR:
 184                 ifam = (struct ifa_msghdr *)rtm;
 185                 if (ifam->ifam_index != ifi->index)
 186                         break;
 187                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
 188                         break;
 189                 sa = get_ifa((char *)(ifam + 1), ifam->ifam_addrs);
 190                 if (sa == NULL) {
 191                         errmsg = "sa == NULL";
 192                         goto die;
 193                 }
 194
 195                 if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf))
 196                         error("king bula sez: len mismatch");
 197                 memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len);
 198                 if (addr_eq(a, defaddr))
 199                         break;
 200
 201                 /* state_panic() can try unexpired existing leases */
 202                 if (client->active && addr_eq(a, client->active->address))
 203                         break;
 204                 for (l = client->leases; l != NULL; l = l->next)
 205                         if (addr_eq(a, l->address))
 206                                 break;
 207
 208                 if (l != NULL)
 209                         /* new addr is the one we set */
 210                         break;
 211                 snprintf(buf, sizeof(buf), "%s: %s",
 212                     "new address not one we set", piaddr(a));
 213                 errmsg = buf;
 214                 goto die;
 215         case RTM_DELADDR:
 216                 ifam = (struct ifa_msghdr *)rtm;
 217                 if (ifam->ifam_index != ifi->index)
 218                         break;
 219                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
 220                         break;
 221                 /* XXX check addrs like RTM_NEWADDR instead of this? */
 222                 if (scripttime == 0 || t < scripttime + 10)
 223                         break;
 224                 errmsg = "interface address deleted";
 225                 goto die;
 226         case RTM_IFINFO:
 227                 ifm = (struct if_msghdr *)rtm;
 228                 if (ifm->ifm_index != ifi->index)
 229                         break;
 230                 if ((rtm->rtm_flags & RTF_UP) == 0) {
 231                         errmsg = "interface down";
 232                         goto die;
 233                 }
 234
 235                 linkstat =
 236                     LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0;
 237                 if (linkstat != ifi->linkstat) {
 238 #ifdef DEBUG
 239                         debug("link state %s -> %s",
 240                             ifi->linkstat ? "up" : "down",
 241                             linkstat ? "up" : "down");
 242 #endif
 243                         ifi->linkstat = interface_link_status(ifi->name);
 244                         if (ifi->linkstat) {
 245                                 client->state = S_INIT;
 246                                 state_reboot();
 247                         }
 248                 }
 249                 break;
 250         case RTM_IFANNOUNCE:
 251                 ifan = (struct if_announcemsghdr *)rtm;
 252                 if (ifan->ifan_what == IFAN_DEPARTURE &&
 253                     ifan->ifan_index == ifi->index) {
 254                         errmsg = "interface departure";
 255                         goto die;
 256                 }
 257                 break;
 258         default:
 259                 break;
 260         }
 261         return;
 262
 263 die:
 264         script_init("FAIL");
 265         script_go();
 266         error("routehandler: %s", errmsg);
 267 }
 268
 269 int
 270 main(int argc, char *argv[])
 271 {
 272         int      ch, fd, quiet = 0, i = 0, pipe_fd[2];
 273         struct passwd *pw;
 274
 275         /* Initially, log errors to stderr as well as to syslogd. */
 276         openlog(getprogname(), LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
 277         setlogmask(LOG_UPTO(LOG_INFO));
 278
 279         while ((ch = getopt(argc, argv, "c:dl:qu")) != -1)
 280                 switch (ch) {
 281                 case 'c':
 282                         path_dhclient_conf = optarg;
 283                         break;
 284                 case 'd':
 285                         no_daemon = 1;
 286                         break;
 287                 case 'l':
 288                         path_dhclient_db = optarg;
 289                         break;
 290                 case 'q':
 291                         quiet = 1;
 292                         break;
 293                 case 'u':
 294                         unknown_ok = 0;
 295                         break;
 296                 default:
 297                         usage();
 298                 }
 299
 300         argc -= optind;
 301         argv += optind;
 302
 303         if (argc != 1)
 304                 usage();
 305
 306         ifi = calloc(1, sizeof(*ifi));
 307         if (ifi == NULL)
 308                 error("ifi calloc");
 309         client = calloc(1, sizeof(*client));
 310         if (client == NULL)
 311                 error("client calloc");
 312         config = calloc(1, sizeof(*config));
 313         if (config == NULL)
 314                 error("config calloc");
 315
 316         get_ifname(ifi->name, argv[0]);
 317         if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s",
 318             _PATH_DHCLIENT_DB, ifi->name) == -1)
 319                 error("asprintf");
 320
 321         if (quiet)
 322                 log_perror = 0;
 323
 324         tzset();
 325         time(&cur_time);
 326
 327         memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
 328         sockaddr_broadcast.sin_family = AF_INET;
 329         sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
 330         sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
 331         sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
 332         inaddr_any.s_addr = INADDR_ANY;
 333
 334         read_client_conf();
 335
 336         if (interface_status(ifi->name) == 0) {
 337                 interface_link_forceup(ifi->name);
 338                 /* Give it up to 4 seconds of silent grace to find link */
 339                 i = -4;
 340         } else
 341                 i = 0;
 342
 343         while (!(ifi->linkstat = interface_link_status(ifi->name))) {
 344                 if (i == 0)
 345                         fprintf(stderr, "%s: no link ...", ifi->name);
 346                 else if (i > 0)
 347                         fprintf(stderr, ".");
 348                 fflush(stderr);
 349                 if (++i > config->link_timeout) {
 350                         fprintf(stderr, " sleeping\n");
 351                         goto dispatch;
 352                 }
 353                 sleep(1);
 354         }
 355         if (i > 0)
 356                 fprintf(stderr, " got link\n");
 357
 358  dispatch:
 359         if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
 360                 error("cannot open %s: %m", _PATH_DEVNULL);
 361
 362         if ((pw = getpwnam("_dhcp")) == NULL)
 363                 error("no such user: _dhcp");
 364
 365         if (pipe(pipe_fd) == -1)
 366                 error("pipe");
 367
 368         fork_privchld(pipe_fd[0], pipe_fd[1]);
 369
 370         close(pipe_fd[0]);
 371         privfd = pipe_fd[1];
 372
 373         if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1)
 374                 error("can't open and lock %s: %m", path_dhclient_db);
 375         read_client_leases();
 376         if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL)
 377                 error("can't open %s: %m", path_dhclient_db);
 378         rewrite_client_leases();
 379         close(fd);
 380
 381         if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1)
 382                 error("socket(PF_ROUTE, SOCK_RAW): %m");
 383
 384         /* set up the interface */
 385         discover_interface();
 386
 387         if (chroot(_PATH_VAREMPTY) == -1)
 388                 error("chroot");
 389         if (chdir("/") == -1)
 390                 error("chdir(\"/\")");
 391
 392         if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
 393                 error("setresgid");
 394         if (setgroups(1, &pw->pw_gid) == -1)
 395                 error("setgroups");
 396         if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
 397                 error("setresuid");
 398
 399         endpwent();
 400
 401         setproctitle("%s", ifi->name);
 402
 403         if (ifi->linkstat) {
 404                 client->state = S_INIT;
 405                 state_reboot();
 406         } else
 407                 go_daemon();
 408
 409         dispatch();
 410
 411         /* not reached */
 412         return (0);
 413 }
 414
 415 void
 416 usage(void)
 417 {
 418         fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n",
 419             getprogname());
 420         exit(1);
 421 }
 422
 423 /*
 424  * Individual States:
 425  *
 426  * Each routine is called from the dhclient_state_machine() in one of
 427  * these conditions:
 428  * -> entering INIT state
 429  * -> recvpacket_flag == 0: timeout in this state
 430  * -> otherwise: received a packet in this state
 431  *
 432  * Return conditions as handled by dhclient_state_machine():
 433  * Returns 1, sendpacket_flag = 1: send packet, reset timer.
 434  * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
 435  * Returns 0: finish the nap which was interrupted for no good reason.
 436  *
 437  * Several per-interface variables are used to keep track of the process:
 438  *   active_lease: the lease that is being used on the interface
 439  *                 (null pointer if not configured yet).
 440  *   offered_leases: leases corresponding to DHCPOFFER messages that have
 441  *                   been sent to us by DHCP servers.
 442  *   acked_leases: leases corresponding to DHCPACK messages that have been
 443  *                 sent to us by DHCP servers.
 444  *   sendpacket: DHCP packet we're trying to send.
 445  *   destination: IP address to send sendpacket to
 446  * In addition, there are several relevant per-lease variables.
 447  *   T1_expiry, T2_expiry, lease_expiry: lease milestones
 448  * In the active lease, these control the process of renewing the lease;
 449  * In leases on the acked_leases list, this simply determines when we
 450  * can no longer legitimately use the lease.
 451  */
 452 void
 453 state_reboot(void)
 454 {
 455         /* If we don't remember an active lease, go straight to INIT. */
 456         if (!client->active || client->active->is_bootp) {
 457                 state_init();
 458                 return;
 459         }
 460
 461         /* We are in the rebooting state. */
 462         client->state = S_REBOOTING;
 463
 464         /* make_request doesn't initialize xid because it normally comes
 465            from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
 466            so pick an xid now. */
 467         client->xid = arc4random();
 468
 469         /* Make a DHCPREQUEST packet, and set appropriate per-interface
 470            flags. */
 471         make_request(client->active);
 472         client->destination = iaddr_broadcast;
 473         client->first_sending = cur_time;
 474         client->interval = 0;
 475
 476         /* Send out the first DHCPREQUEST packet. */
 477         send_request();
 478 }
 479
 480 /*
 481  * Called when a lease has completely expired and we've
 482  * been unable to renew it.
 483  */
 484 void
 485 state_init(void)
 486 {
 487         /* Make a DHCPDISCOVER packet, and set appropriate per-interface
 488            flags. */
 489         make_discover(client->active);
 490         client->xid = client->packet.xid;
 491         client->destination = iaddr_broadcast;
 492         client->state = S_SELECTING;
 493         client->first_sending = cur_time;
 494         client->interval = 0;
 495
 496         /* Add an immediate timeout to cause the first DHCPDISCOVER packet
 497            to go out. */
 498         send_discover();
 499 }
 500
 501 /*
 502  * state_selecting is called when one or more DHCPOFFER packets
 503  * have been received and a configurable period of time has passed.
 504  */
 505 void
 506 state_selecting(void)
 507 {
 508         struct client_lease *lp, *next, *picked;
 509
 510         /* Cancel state_selecting and send_discover timeouts, since either
 511            one could have got us here. */
 512         cancel_timeout(state_selecting);
 513         cancel_timeout(send_discover);
 514
 515         /* We have received one or more DHCPOFFER packets.   Currently,
 516            the only criterion by which we judge leases is whether or
 517            not we get a response when we arp for them. */
 518         picked = NULL;
 519         for (lp = client->offered_leases; lp; lp = next) {
 520                 next = lp->next;
 521
 522                 if (!picked) {
 523                         picked = lp;
 524                 } else {
 525                         make_decline(lp);
 526                         send_decline();
 527                         free_client_lease(lp);
 528                 }
 529         }
 530         client->offered_leases = NULL;
 531
 532         /* If we just tossed all the leases we were offered, go back
 533            to square one. */
 534         if (!picked) {
 535                 client->state = S_INIT;
 536                 state_init();
 537                 return;
 538         }
 539         picked->next = NULL;
 540
 541         /* If it was a BOOTREPLY, we can just take the address right now. */
 542         if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) {
 543                 client->new = picked;
 544
 545                 /* Make up some lease expiry times
 546                    XXX these should be configurable. */
 547                 client->new->expiry = cur_time + 12000;
 548                 client->new->renewal += cur_time + 8000;
 549                 client->new->rebind += cur_time + 10000;
 550
 551                 client->state = S_REQUESTING;
 552
 553                 /* Bind to the address we received. */
 554                 bind_lease();
 555                 return;
 556         }
 557
 558         /* Go to the REQUESTING state. */
 559         client->destination = iaddr_broadcast;
 560         client->state = S_REQUESTING;
 561         client->first_sending = cur_time;
 562         client->interval = 0;
 563
 564         /* Make a DHCPREQUEST packet from the lease we picked. */
 565         make_request(picked);
 566         client->xid = client->packet.xid;
 567
 568         /* Toss the lease we picked - we'll get it back in a DHCPACK. */
 569         free_client_lease(picked);
 570
 571         /* Add an immediate timeout to send the first DHCPREQUEST packet. */
 572         send_request();
 573 }
 574
 575 void
 576 dhcpack(struct iaddr client_addr, struct option_data *options)
 577 {
 578         struct client_lease *lease;
 579
 580
 581         if (client->state != S_REBOOTING &&
 582             client->state != S_REQUESTING &&
 583             client->state != S_RENEWING &&
 584             client->state != S_REBINDING)
 585                 return;
 586
 587
 588         lease = packet_to_lease(options);
 589         if (!lease) {
 590                 note("packet_to_lease failed.");
 591                 return;
 592         }
 593
 594         client->new = lease;
 595
 596         /* Stop resending DHCPREQUEST. */
 597         cancel_timeout(send_request);
 598
 599         /* Figure out the lease time. */
 600         if (client->new->options[DHO_DHCP_LEASE_TIME].data)
 601                 client->new->expiry =
 602                     getULong(client->new->options[DHO_DHCP_LEASE_TIME].data);
 603         else
 604                 client->new->expiry = DEFAULT_LEASE_TIME;
 605         /* A number that looks negative here is really just very large,
 606            because the lease expiry offset is unsigned. */
 607         if (client->new->expiry < 0)
 608                 client->new->expiry = TIME_MAX;
 609         /* XXX should be fixed by resetting the client state */
 610         if (client->new->expiry < 60)
 611                 client->new->expiry = 60;
 612
 613         /* Take the server-provided renewal time if there is one;
 614            otherwise figure it out according to the spec. */
 615         if (client->new->options[DHO_DHCP_RENEWAL_TIME].len)
 616                 client->new->renewal =
 617                     getULong(client->new->options[DHO_DHCP_RENEWAL_TIME].data);
 618         else
 619                 client->new->renewal = client->new->expiry / 2;
 620
 621         /* Same deal with the rebind time. */
 622         if (client->new->options[DHO_DHCP_REBINDING_TIME].len)
 623                 client->new->rebind =
 624                     getULong(client->new->options[DHO_DHCP_REBINDING_TIME].data);
 625         else
 626                 client->new->rebind = client->new->renewal +
 627                     client->new->renewal / 2 + client->new->renewal / 4;
 628
 629         client->new->expiry += cur_time;
 630         /* Lease lengths can never be negative. */
 631         if (client->new->expiry < cur_time)
 632                 client->new->expiry = TIME_MAX;
 633         client->new->renewal += cur_time;
 634         if (client->new->renewal < cur_time)
 635                 client->new->renewal = TIME_MAX;
 636         client->new->rebind += cur_time;
 637         if (client->new->rebind < cur_time)
 638                 client->new->rebind = TIME_MAX;
 639
 640         bind_lease();
 641 }
 642
 643 void
 644 bind_lease(void)
 645 {
 646         /* Write out the new lease. */
 647         write_client_lease(client->new, 0);
 648
 649         /* Run the client script with the new parameters. */
 650         script_init((client->state == S_REQUESTING ? "BOUND" :
 651             (client->state == S_RENEWING ? "RENEW" :
 652                 (client->state == S_REBOOTING ? "REBOOT" : "REBIND"))));
 653         if (client->active && client->state != S_REBOOTING)
 654                 script_write_params("old_", client->active);
 655         script_write_params("new_", client->new);
 656         script_go();
 657
 658         /* Replace the old active lease with the new one. */
 659         if (client->active)
 660                 free_client_lease(client->active);
 661         client->active = client->new;
 662         client->new = NULL;
 663
 664         /* Set up a timeout to start the renewal process. */
 665         add_timeout(client->active->renewal, state_bound);
 666
 667         note("bound to %s -- renewal in %ld seconds.",
 668             piaddr(client->active->address),
 669             client->active->renewal - cur_time);
 670         client->state = S_BOUND;
 671         reinitialize_interface();
 672         go_daemon();
 673 }
 674
 675 /*
 676  * state_bound is called when we've successfully bound to a particular
 677  * lease, but the renewal time on that lease has expired.   We are
 678  * expected to unicast a DHCPREQUEST to the server that gave us our
 679  * original lease.
 680  */
 681 void
 682 state_bound(void)
 683 {
 684         /* T1 has expired. */
 685         make_request(client->active);
 686         client->xid = client->packet.xid;
 687
 688         if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
 689                 memcpy(client->destination.iabuf,
 690                     client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data,
 691                     4);
 692                 client->destination.len = 4;
 693         } else
 694                 client->destination = iaddr_broadcast;
 695
 696         client->first_sending = cur_time;
 697         client->interval = 0;
 698         client->state = S_RENEWING;
 699
 700         /* Send the first packet immediately. */
 701         send_request();
 702 }
 703
 704 void
 705 dhcpoffer(struct iaddr client_addr, struct option_data *options)
 706 {
 707         struct client_lease *lease, *lp;
 708         int i;
 709         int stop_selecting;
 710         char *name = options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" :
 711             "BOOTREPLY";
 712
 713
 714         if (client->state != S_SELECTING)
 715                 return;
 716
 717
 718         /* If this lease doesn't supply the minimum required parameters,
 719            blow it off. */
 720         for (i = 0; config->required_options[i]; i++) {
 721                 if (!options[config->required_options[i]].len) {
 722                         note("%s isn't satisfactory.", name);
 723                         return;
 724                 }
 725         }
 726
 727         /* If we've already seen this lease, don't record it again. */
 728         for (lease = client->offered_leases;
 729             lease; lease = lease->next) {
 730                 if (lease->address.len == sizeof(client->packet.yiaddr) &&
 731                     !memcmp(lease->address.iabuf,
 732                     &client->packet.yiaddr, lease->address.len)) {
 733 #ifdef DEBUG
 734                         debug("%s already seen.", name);
 735 #endif
 736                         return;
 737                 }
 738         }
 739
 740         lease = packet_to_lease(options);
 741         if (!lease) {
 742                 note("packet_to_lease failed.");
 743                 return;
 744         }
 745
 746         /* If this lease was acquired through a BOOTREPLY, record that
 747            fact. */
 748         if (!options[DHO_DHCP_MESSAGE_TYPE].len)
 749                 lease->is_bootp = 1;
 750
 751         /* Figure out when we're supposed to stop selecting. */
 752         stop_selecting = client->first_sending + config->select_interval;
 753
 754         /* If this is the lease we asked for, put it at the head of the
 755            list, and don't mess with the arp request timeout. */
 756         if (addr_eq(lease->address, client->requested_address)) {
 757                 lease->next = client->offered_leases;
 758                 client->offered_leases = lease;
 759         } else {
 760                 /* Put the lease at the end of the list. */
 761                 lease->next = NULL;
 762                 if (!client->offered_leases)
 763                         client->offered_leases = lease;
 764                 else {
 765                         for (lp = client->offered_leases; lp->next;
 766                             lp = lp->next)
 767                                 ;       /* nothing */
 768                         lp->next = lease;
 769                 }
 770         }
 771
 772         /* If the selecting interval has expired, go immediately to
 773            state_selecting().  Otherwise, time out into
 774            state_selecting at the select interval. */
 775         if (stop_selecting <= cur_time)
 776                 state_selecting();
 777         else {
 778                 add_timeout(stop_selecting, state_selecting);
 779                 cancel_timeout(send_discover);
 780         }
 781 }
 782
 783 /*
 784  * Allocate a client_lease structure and initialize it from the
 785  * parameters in the specified packet.
 786  */
 787 struct client_lease *
 788 packet_to_lease(struct option_data *options)
 789 {
 790         struct client_lease *lease;
 791         int i;
 792
 793         lease = malloc(sizeof(struct client_lease));
 794
 795         if (!lease) {
 796                 warning("dhcpoffer: no memory to record lease.");
 797                 return (NULL);
 798         }
 799
 800         memset(lease, 0, sizeof(*lease));
 801
 802         /* Copy the lease options. */
 803         for (i = 0; i < 256; i++) {
 804                 if (options[i].len) {
 805                         lease->options[i] = options[i];
 806                         options[i].data = NULL;
 807                         options[i].len = 0;
 808                         if (!check_option(lease, i)) {
 809                                 warning("Invalid lease option - ignoring offer");
 810                                 free_client_lease(lease);
 811                                 return (NULL);
 812                         }
 813                 }
 814         }
 815
 816         lease->address.len = sizeof(client->packet.yiaddr);
 817         memcpy(lease->address.iabuf, &client->packet.yiaddr,
 818             lease->address.len);
 819
 820         /* If the server name was filled out, copy it. */
 821         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
 822             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
 823             client->packet.sname[0]) {
 824                 lease->server_name = malloc(DHCP_SNAME_LEN + 1);
 825                 if (!lease->server_name) {
 826                         warning("dhcpoffer: no memory for server name.");
 827                         free_client_lease(lease);
 828                         return (NULL);
 829                 }
 830                 memcpy(lease->server_name, client->packet.sname,
 831                     DHCP_SNAME_LEN);
 832                 lease->server_name[DHCP_SNAME_LEN] = '\0';
 833                 if (!res_hnok(lease->server_name)) {
 834                         warning("Bogus server name %s", lease->server_name);
 835                         free(lease->server_name);
 836                         lease->server_name = NULL;
 837                 }
 838         }
 839
 840         /* Ditto for the filename. */
 841         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
 842             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) &&
 843             client->packet.file[0]) {
 844                 /* Don't count on the NUL terminator. */
 845                 lease->filename = malloc(DHCP_FILE_LEN + 1);
 846                 if (!lease->filename) {
 847                         warning("dhcpoffer: no memory for filename.");
 848                         free_client_lease(lease);
 849                         return (NULL);
 850                 }
 851                 memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN);
 852                 lease->filename[DHCP_FILE_LEN] = '\0';
 853         }
 854         return lease;
 855 }
 856
 857 void
 858 dhcpnak(struct iaddr client_addr, struct option_data *options)
 859 {
 860
 861         if (client->state != S_REBOOTING &&
 862             client->state != S_REQUESTING &&
 863             client->state != S_RENEWING &&
 864             client->state != S_REBINDING)
 865                 return;
 866
 867
 868         if (!client->active) {
 869                 note("DHCPNAK with no active lease.");
 870                 return;
 871         }
 872
 873         free_client_lease(client->active);
 874         client->active = NULL;
 875
 876         /* Stop sending DHCPREQUEST packets... */
 877         cancel_timeout(send_request);
 878
 879         client->state = S_INIT;
 880         state_init();
 881 }
 882
 883 /*
 884  * Send out a DHCPDISCOVER packet, and set a timeout to send out another
 885  * one after the right interval has expired.  If we don't get an offer by
 886  * the time we reach the panic interval, call the panic function.
 887  */
 888 void
 889 send_discover(void)
 890 {
 891         int interval, increase = 1;
 892
 893         /* Figure out how long it's been since we started transmitting. */
 894         interval = cur_time - client->first_sending;
 895
 896         /* If we're past the panic timeout, call the script and tell it
 897            we haven't found anything for this interface yet. */
 898         if (interval > config->timeout) {
 899                 state_panic();
 900                 return;
 901         }
 902
 903         /*
 904          * If we're supposed to increase the interval, do so.  If it's
 905          * currently zero (i.e., we haven't sent any packets yet), set
 906          * it to initial_interval; otherwise, add to it a random
 907          * number between zero and two times itself.  On average, this
 908          * means that it will double with every transmission.
 909          */
 910         if (increase) {
 911                 if (!client->interval)
 912                         client->interval = config->initial_interval;
 913                 else {
 914                         client->interval += (arc4random() >> 2) %
 915                             (2 * client->interval);
 916                 }
 917
 918                 /* Don't backoff past cutoff. */
 919                 if (client->interval > config->backoff_cutoff)
 920                         client->interval = ((config->backoff_cutoff / 2)
 921                                  + ((arc4random() >> 2) %
 922                                     config->backoff_cutoff));
 923         } else if (!client->interval)
 924                 client->interval = config->initial_interval;
 925
 926         /* If the backoff would take us to the panic timeout, just use that
 927            as the interval. */
 928         if (cur_time + client->interval >
 929             client->first_sending + config->timeout)
 930                 client->interval = (client->first_sending +
 931                          config->timeout) - cur_time + 1;
 932
 933         /* Record the number of seconds since we started sending. */
 934         if (interval < 65536)
 935                 client->packet.secs = htons(interval);
 936         else
 937                 client->packet.secs = htons(65535);
 938         client->secs = client->packet.secs;
 939
 940         note("DHCPDISCOVER on %s to %s port %d interval %ld",
 941             ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr),
 942             ntohs(sockaddr_broadcast.sin_port), client->interval);
 943
 944         /* Send out a packet. */
 945         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
 946
 947         add_timeout(cur_time + client->interval, send_discover);
 948 }
 949
 950 /*
 951  * state_panic gets called if we haven't received any offers in a preset
 952  * amount of time.   When this happens, we try to use existing leases
 953  * that haven't yet expired, and failing that, we call the client script
 954  * and hope it can do something.
 955  */
 956 void
 957 state_panic(void)
 958 {
 959         struct client_lease *loop = client->active;
 960         struct client_lease *lp;
 961
 962         note("No DHCPOFFERS received.");
 963
 964         /* We may not have an active lease, but we may have some
 965            predefined leases that we can try. */
 966         if (!client->active && client->leases)
 967                 goto activate_next;
 968
 969         /* Run through the list of leases and see if one can be used. */
 970         while (client->active) {
 971                 if (client->active->expiry > cur_time) {
 972                         note("Trying recorded lease %s",
 973                             piaddr(client->active->address));
 974                         /* Run the client script with the existing
 975                            parameters. */
 976                         script_init("TIMEOUT");
 977                         script_write_params("new_", client->active);
 978
 979                         /* If the old lease is still good and doesn't
 980                            yet need renewal, go into BOUND state and
 981                            timeout at the renewal time. */
 982                         if (!script_go()) {
 983                                 if (cur_time <
 984                                     client->active->renewal) {
 985                                         client->state = S_BOUND;
 986                                         note("bound: renewal in %ld seconds.",
 987                                             client->active->renewal -
 988                                             cur_time);
 989                                         add_timeout(client->active->renewal,
 990                                             state_bound);
 991                                 } else {
 992                                         client->state = S_BOUND;
 993                                         note("bound: immediate renewal.");
 994                                         state_bound();
 995                                 }
 996                                 reinitialize_interface();
 997                                 go_daemon();
 998                                 return;
 999                         }
1000                 }
1001
1002                 /* If there are no other leases, give up. */
1003                 if (!client->leases) {
1004                         client->leases = client->active;
1005                         client->active = NULL;
1006                         break;
1007                 }
1008
1009 activate_next:
1010                 /* Otherwise, put the active lease at the end of the
1011                    lease list, and try another lease.. */
1012                 for (lp = client->leases; lp->next; lp = lp->next)
1013                         ;
1014                 lp->next = client->active;
1015                 if (lp->next)
1016                         lp->next->next = NULL;
1017                 client->active = client->leases;
1018                 client->leases = client->leases->next;
1019
1020                 /* If we already tried this lease, we've exhausted the
1021                    set of leases, so we might as well give up for
1022                    now. */
1023                 if (client->active == loop)
1024                         break;
1025                 else if (!loop)
1026                         loop = client->active;
1027         }
1028
1029         /* No leases were available, or what was available didn't work, so
1030            tell the shell script that we failed to allocate an address,
1031            and try again later. */
1032         note("No working leases in persistent database - sleeping.");
1033         script_init("FAIL");
1034         script_go();
1035         client->state = S_INIT;
1036         add_timeout(cur_time + config->retry_interval, state_init);
1037         go_daemon();
1038 }
1039
1040 void
1041 send_request(void)
1042 {
1043         struct sockaddr_in destination;
1044         struct in_addr from;
1045         int interval;
1046
1047         /* Figure out how long it's been since we started transmitting. */
1048         interval = cur_time - client->first_sending;
1049
1050         /* If we're in the INIT-REBOOT or REQUESTING state and we're
1051            past the reboot timeout, go to INIT and see if we can
1052            DISCOVER an address... */
1053         /* XXX In the INIT-REBOOT state, if we don't get an ACK, it
1054            means either that we're on a network with no DHCP server,
1055            or that our server is down.  In the latter case, assuming
1056            that there is a backup DHCP server, DHCPDISCOVER will get
1057            us a new address, but we could also have successfully
1058            reused our old address.  In the former case, we're hosed
1059            anyway.  This is not a win-prone situation. */
1060         if ((client->state == S_REBOOTING ||
1061             client->state == S_REQUESTING) &&
1062             interval > config->reboot_timeout) {
1063                 client->state = S_INIT;
1064                 cancel_timeout(send_request);
1065                 state_init();
1066                 return;
1067         }
1068
1069         /* If the lease has expired, relinquish the address and go back
1070            to the INIT state. */
1071         if (client->state != S_REQUESTING &&
1072             cur_time > client->active->expiry) {
1073                 /* Run the client script with the new parameters. */
1074                 script_init("EXPIRE");
1075                 script_write_params("old_", client->active);
1076                 script_go();
1077
1078                 client->state = S_INIT;
1079                 state_init();
1080                 return;
1081         }
1082
1083         /* Do the exponential backoff... */
1084         if (!client->interval)
1085                 client->interval = config->initial_interval;
1086         else
1087                 client->interval += ((arc4random() >> 2) %
1088                     (2 * client->interval));
1089
1090         /* Don't backoff past cutoff. */
1091         if (client->interval > config->backoff_cutoff)
1092                 client->interval = ((config->backoff_cutoff / 2) +
1093                     ((arc4random() >> 2) % client->interval));
1094
1095         /* If the backoff would take us to the expiry time, just set the
1096            timeout to the expiry time. */
1097         if (client->state != S_REQUESTING && cur_time + client->interval >
1098             client->active->expiry)
1099                 client->interval = client->active->expiry - cur_time + 1;
1100
1101         /* If the lease T2 time has elapsed, or if we're not yet bound,
1102            broadcast the DHCPREQUEST rather than unicasting. */
1103         memset(&destination, 0, sizeof(destination));
1104         if (client->state == S_REQUESTING ||
1105             client->state == S_REBOOTING ||
1106             cur_time > client->active->rebind)
1107                 destination.sin_addr.s_addr = INADDR_BROADCAST;
1108         else
1109                 memcpy(&destination.sin_addr.s_addr, client->destination.iabuf,
1110                     sizeof(destination.sin_addr.s_addr));
1111         destination.sin_port = htons(REMOTE_PORT);
1112         destination.sin_family = AF_INET;
1113         destination.sin_len = sizeof(destination);
1114
1115         if (client->state != S_REQUESTING)
1116                 memcpy(&from, client->active->address.iabuf, sizeof(from));
1117         else
1118                 from.s_addr = INADDR_ANY;
1119
1120         /* Record the number of seconds since we started sending. */
1121         if (client->state == S_REQUESTING)
1122                 client->packet.secs = client->secs;
1123         else {
1124                 if (interval < 65536)
1125                         client->packet.secs = htons(interval);
1126                 else
1127                         client->packet.secs = htons(65535);
1128         }
1129
1130         note("DHCPREQUEST on %s to %s port %d", ifi->name,
1131             inet_ntoa(destination.sin_addr), ntohs(destination.sin_port));
1132
1133         /* Send out a packet. */
1134         send_packet(from, &destination, NULL);
1135
1136         add_timeout(cur_time + client->interval, send_request);
1137 }
1138
1139 void
1140 send_decline(void)
1141 {
1142         note("DHCPDECLINE on %s to %s port %d", ifi->name,
1143             inet_ntoa(sockaddr_broadcast.sin_addr),
1144             ntohs(sockaddr_broadcast.sin_port));
1145
1146         /* Send out a packet. */
1147         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1148 }
1149
1150 void
1151 make_discover(struct client_lease *lease)
1152 {
1153         unsigned char discover = DHCPDISCOVER;
1154         struct option_data options[256];
1155         int i;
1156
1157         memset(options, 0, sizeof(options));
1158         memset(&client->packet, 0, sizeof(client->packet));
1159
1160         /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */
1161         i = DHO_DHCP_MESSAGE_TYPE;
1162         options[i].data = &discover;
1163         options[i].len = sizeof(discover);
1164
1165         /* Request the options we want */
1166         i  = DHO_DHCP_PARAMETER_REQUEST_LIST;
1167         options[i].data = config->requested_options;
1168         options[i].len = config->requested_option_count;
1169
1170         /* If we had an address, try to get it again. */
1171         if (lease) {
1172                 client->requested_address = lease->address;
1173                 i = DHO_DHCP_REQUESTED_ADDRESS;
1174                 options[i].data = lease->address.iabuf;
1175                 options[i].len = lease->address.len;
1176         } else
1177                 client->requested_address.len = 0;
1178
1179         /* Send any options requested in the config file. */
1180         for (i = 0; i < 256; i++)
1181                 if (!options[i].data &&
1182                     config->send_options[i].data) {
1183                         options[i].data = config->send_options[i].data;
1184                         options[i].len = config->send_options[i].len;
1185                 }
1186
1187         /* Set up the option buffer to fit in a minimal UDP packet. */
1188         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1189             options);
1190         if (i == -1 || client->packet.options[i] != DHO_END)
1191                 error("options do not fit in DHCPDISCOVER packet.");
1192         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1193         if (client->packet_length < BOOTP_MIN_LEN)
1194                 client->packet_length = BOOTP_MIN_LEN;
1195
1196         client->packet.op = BOOTREQUEST;
1197         client->packet.htype = ifi->hw_address.htype;
1198         client->packet.hlen = ifi->hw_address.hlen;
1199         client->packet.hops = 0;
1200         client->packet.xid = arc4random();
1201         client->packet.secs = 0; /* filled in by send_discover. */
1202         client->packet.flags = 0;
1203
1204         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1205         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1206         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1207         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1208         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1209             ifi->hw_address.hlen);
1210 }
1211
1212 void
1213 make_request(struct client_lease * lease)
1214 {
1215         unsigned char request = DHCPREQUEST;
1216         struct option_data options[256];
1217         int i;
1218
1219         memset(options, 0, sizeof(options));
1220         memset(&client->packet, 0, sizeof(client->packet));
1221
1222         /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
1223         i = DHO_DHCP_MESSAGE_TYPE;
1224         options[i].data = &request;
1225         options[i].len = sizeof(request);
1226
1227         /* Request the options we want */
1228         i = DHO_DHCP_PARAMETER_REQUEST_LIST;
1229         options[i].data = config->requested_options;
1230         options[i].len = config->requested_option_count;
1231
1232         /* If we are requesting an address that hasn't yet been assigned
1233            to us, use the DHCP Requested Address option. */
1234         if (client->state == S_REQUESTING) {
1235                 /* Send back the server identifier... */
1236                 i = DHO_DHCP_SERVER_IDENTIFIER;
1237                 options[i].data = lease->options[i].data;
1238                 options[i].len = lease->options[i].len;
1239         }
1240         if (client->state == S_REQUESTING ||
1241             client->state == S_REBOOTING) {
1242                 client->requested_address = lease->address;
1243                 i = DHO_DHCP_REQUESTED_ADDRESS;
1244                 options[i].data = lease->address.iabuf;
1245                 options[i].len = lease->address.len;
1246         } else
1247                 client->requested_address.len = 0;
1248
1249         /* Send any options requested in the config file. */
1250         for (i = 0; i < 256; i++)
1251                 if (!options[i].data && config->send_options[i].data) {
1252                         options[i].data = config->send_options[i].data;
1253                         options[i].len = config->send_options[i].len;
1254                 }
1255
1256         /* Set up the option buffer to fit in a minimal UDP packet. */
1257         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1258             options);
1259         if (i == -1 || client->packet.options[i] != DHO_END)
1260                 error("options do not fit in DHCPREQUEST packet.");
1261         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1262         if (client->packet_length < BOOTP_MIN_LEN)
1263                 client->packet_length = BOOTP_MIN_LEN;
1264
1265         client->packet.op = BOOTREQUEST;
1266         client->packet.htype = ifi->hw_address.htype;
1267         client->packet.hlen = ifi->hw_address.hlen;
1268         client->packet.hops = 0;
1269         client->packet.xid = client->xid;
1270         client->packet.secs = 0; /* Filled in by send_request. */
1271         client->packet.flags = 0;
1272
1273         /* If we own the address we're requesting, put it in ciaddr;
1274            otherwise set ciaddr to zero. */
1275         if (client->state == S_BOUND ||
1276             client->state == S_RENEWING ||
1277             client->state == S_REBINDING) {
1278                 memcpy(&client->packet.ciaddr,
1279                     lease->address.iabuf, lease->address.len);
1280         } else {
1281                 memset(&client->packet.ciaddr, 0,
1282                     sizeof(client->packet.ciaddr));
1283         }
1284
1285         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1286         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1287         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1288         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1289             ifi->hw_address.hlen);
1290 }
1291
1292 void
1293 make_decline(struct client_lease *lease)
1294 {
1295         struct option_data options[256];
1296         unsigned char decline = DHCPDECLINE;
1297         int i;
1298
1299         memset(options, 0, sizeof(options));
1300         memset(&client->packet, 0, sizeof(client->packet));
1301
1302         /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */
1303         i = DHO_DHCP_MESSAGE_TYPE;
1304         options[i].data = &decline;
1305         options[i].len = sizeof(decline);
1306
1307         /* Send back the server identifier... */
1308         i = DHO_DHCP_SERVER_IDENTIFIER;
1309         options[i].data = lease->options[i].data;
1310         options[i].len = lease->options[i].len;
1311
1312         /* Send back the address we're declining. */
1313         i = DHO_DHCP_REQUESTED_ADDRESS;
1314         options[i].data = lease->address.iabuf;
1315         options[i].len = lease->address.len;
1316
1317         /* Send the uid if the user supplied one. */
1318         i = DHO_DHCP_CLIENT_IDENTIFIER;
1319         if (config->send_options[i].len) {
1320                 options[i].data = config->send_options[i].data;
1321                 options[i].len = config->send_options[i].len;
1322         }
1323
1324         /* Set up the option buffer to fit in a minimal UDP packet. */
1325         i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN,
1326             options);
1327         if (i == -1 || client->packet.options[i] != DHO_END)
1328                 error("options do not fit in DHCPDECLINE packet.");
1329         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1330         if (client->packet_length < BOOTP_MIN_LEN)
1331                 client->packet_length = BOOTP_MIN_LEN;
1332
1333         client->packet.op = BOOTREQUEST;
1334         client->packet.htype = ifi->hw_address.htype;
1335         client->packet.hlen = ifi->hw_address.hlen;
1336         client->packet.hops = 0;
1337         client->packet.xid = client->xid;
1338         client->packet.secs = 0; /* Filled in by send_request. */
1339         client->packet.flags = 0;
1340
1341         /* ciaddr must always be zero. */
1342         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1343         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1344         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1345         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1346         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1347             ifi->hw_address.hlen);
1348 }
1349
1350 void
1351 free_client_lease(struct client_lease *lease)
1352 {
1353         int i;
1354
1355         if (lease->server_name)
1356                 free(lease->server_name);
1357         if (lease->filename)
1358                 free(lease->filename);
1359         for (i = 0; i < 256; i++) {
1360                 if (lease->options[i].len)
1361                         free(lease->options[i].data);
1362         }
1363         free(lease);
1364 }
1365
1366 void
1367 rewrite_client_leases(void)
1368 {
1369         struct client_lease *lp;
1370
1371         if (!leaseFile) /* XXX */
1372                 error("lease file not open");
1373
1374         fflush(leaseFile);
1375         rewind(leaseFile);
1376
1377         for (lp = client->leases; lp; lp = lp->next)
1378                 write_client_lease(lp, 1);
1379         if (client->active)
1380                 write_client_lease(client->active, 1);
1381
1382         fflush(leaseFile);
1383         ftruncate(fileno(leaseFile), ftello(leaseFile));
1384         fsync(fileno(leaseFile));
1385 }
1386
1387 void
1388 write_client_lease(struct client_lease *lease, int rewrite)
1389 {
1390         static int leases_written;
1391         struct tm *t;
1392         int i;
1393
1394         if (!rewrite) {
1395                 if (leases_written++ > 20) {
1396                         rewrite_client_leases();
1397                         leases_written = 0;
1398                 }
1399         }
1400
1401         /* If the lease came from the config file, we don't need to stash
1402            a copy in the lease database. */
1403         if (lease->is_static)
1404                 return;
1405
1406         if (!leaseFile) /* XXX */
1407                 error("lease file not open");
1408
1409         fprintf(leaseFile, "lease {\n");
1410         if (lease->is_bootp)
1411                 fprintf(leaseFile, "  bootp;\n");
1412         fprintf(leaseFile, "  interface \"%s\";\n", ifi->name);
1413         fprintf(leaseFile, "  fixed-address %s;\n", piaddr(lease->address));
1414         if (lease->filename)
1415                 fprintf(leaseFile, "  filename \"%s\";\n", lease->filename);
1416         if (lease->server_name)
1417                 fprintf(leaseFile, "  server-name \"%s\";\n",
1418                     lease->server_name);
1419         for (i = 0; i < 256; i++)
1420                 if (lease->options[i].len)
1421                         fprintf(leaseFile, "  option %s %s;\n",
1422                             dhcp_options[i].name,
1423                             pretty_print_option(i, lease->options[i].data,
1424                             lease->options[i].len, 1, 1));
1425
1426         t = gmtime(&lease->renewal);
1427         fprintf(leaseFile, "  renew %d %d/%d/%d %02d:%02d:%02d;\n",
1428             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1429             t->tm_hour, t->tm_min, t->tm_sec);
1430         t = gmtime(&lease->rebind);
1431         fprintf(leaseFile, "  rebind %d %d/%d/%d %02d:%02d:%02d;\n",
1432             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1433             t->tm_hour, t->tm_min, t->tm_sec);
1434         t = gmtime(&lease->expiry);
1435         fprintf(leaseFile, "  expire %d %d/%d/%d %02d:%02d:%02d;\n",
1436             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1437             t->tm_hour, t->tm_min, t->tm_sec);
1438         fprintf(leaseFile, "}\n");
1439         fflush(leaseFile);
1440 }
1441
1442 void
1443 script_init(char *reason)
1444 {
1445         size_t           len;
1446         struct imsg_hdr  hdr;
1447         struct buf      *buf;
1448
1449         hdr.code = IMSG_SCRIPT_INIT;
1450         hdr.len = sizeof(struct imsg_hdr) + sizeof(size_t) + strlen(reason);
1451         buf = buf_open(hdr.len);
1452
1453         buf_add(buf, &hdr, sizeof(hdr));
1454         len = strlen(reason);
1455         buf_add(buf, &len, sizeof(len));
1456         buf_add(buf, reason, len);
1457
1458         buf_close(privfd, buf);
1459 }
1460
1461 void
1462 priv_script_init(char *reason)
1463 {
1464         client->scriptEnvsize = 100;
1465         if (client->scriptEnv == NULL)
1466                 client->scriptEnv =
1467                     calloc(client->scriptEnvsize, sizeof(char *));
1468         if (client->scriptEnv == NULL)
1469                 error("script_init: no memory for environment");
1470
1471         client->scriptEnv[0] = strdup(CLIENT_PATH);
1472         if (client->scriptEnv[0] == NULL)
1473                 error("script_init: no memory for environment");
1474
1475         client->scriptEnv[1] = NULL;
1476
1477         script_set_env("", "interface", ifi->name);
1478
1479         script_set_env("", "reason", reason);
1480 }
1481
1482 void
1483 priv_script_write_params(char *prefix, struct client_lease *lease)
1484 {
1485         u_int8_t dbuf[1500];
1486         int i, len = 0;
1487         char tbuf[128];
1488
1489         script_set_env(prefix, "ip_address", piaddr(lease->address));
1490
1491         if (lease->options[DHO_SUBNET_MASK].len &&
1492             (lease->options[DHO_SUBNET_MASK].len <
1493             sizeof(lease->address.iabuf))) {
1494                 struct iaddr netmask, subnet, broadcast;
1495
1496                 memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data,
1497                     lease->options[DHO_SUBNET_MASK].len);
1498                 netmask.len = lease->options[DHO_SUBNET_MASK].len;
1499
1500                 subnet = subnet_number(lease->address, netmask);
1501                 if (subnet.len) {
1502                         script_set_env(prefix, "network_number",
1503                             piaddr(subnet));
1504                         if (!lease->options[DHO_BROADCAST_ADDRESS].len) {
1505                                 broadcast = broadcast_addr(subnet, netmask);
1506                                 if (broadcast.len)
1507                                         script_set_env(prefix,
1508                                             "broadcast_address",
1509                                             piaddr(broadcast));
1510                         }
1511                 }
1512         }
1513
1514         if (lease->filename)
1515                 script_set_env(prefix, "filename", lease->filename);
1516         if (lease->server_name)
1517                 script_set_env(prefix, "server_name",
1518                     lease->server_name);
1519         for (i = 0; i < 256; i++) {
1520                 u_int8_t *dp = NULL;
1521
1522                 if (config->defaults[i].len) {
1523                         if (lease->options[i].len) {
1524                                 switch (config->default_actions[i]) {
1525                                 case ACTION_DEFAULT:
1526                                         dp = lease->options[i].data;
1527                                         len = lease->options[i].len;
1528                                         break;
1529                                 case ACTION_SUPERSEDE:
1530 supersede:
1531                                         dp = config->defaults[i].data;
1532                                         len = config->defaults[i].len;
1533                                         break;
1534                                 case ACTION_PREPEND:
1535                                         len = config->defaults[i].len +
1536                                             lease->options[i].len;
1537                                         if (len >= sizeof(dbuf)) {
1538                                                 warning("no space to %s %s",
1539                                                     "prepend option",
1540                                                     dhcp_options[i].name);
1541                                                 goto supersede;
1542                                         }
1543                                         dp = dbuf;
1544                                         memcpy(dp,
1545                                             config->defaults[i].data,
1546                                             config->defaults[i].len);
1547                                         memcpy(dp +
1548                                             config->defaults[i].len,
1549                                             lease->options[i].data,
1550                                             lease->options[i].len);
1551                                         dp[len] = '\0';
1552                                         break;
1553                                 case ACTION_APPEND:
1554                                         len = config->defaults[i].len +
1555                                             lease->options[i].len;
1556                                         if (len >= sizeof(dbuf)) {
1557                                                 warning("no space to %s %s",
1558                                                     "append option",
1559                                                     dhcp_options[i].name);
1560                                                 goto supersede;
1561                                         }
1562                                         dp = dbuf;
1563                                         memcpy(dp, lease->options[i].data,
1564                                             lease->options[i].len);
1565                                         memcpy(dp + lease->options[i].len,
1566                                             config->defaults[i].data,
1567                                             config->defaults[i].len);
1568                                         dp[len] = '\0';
1569                                 }
1570                         } else {
1571                                 dp = config->defaults[i].data;
1572                                 len = config->defaults[i].len;
1573                         }
1574                 } else if (lease->options[i].len) {
1575                         len = lease->options[i].len;
1576                         dp = lease->options[i].data;
1577                 } else {
1578                         len = 0;
1579                 }
1580                 if (len) {
1581                         char name[256];
1582
1583                         if (dhcp_option_ev_name(name, sizeof(name),
1584                             &dhcp_options[i]))
1585                                 script_set_env(prefix, name,
1586                                     pretty_print_option(i, dp, len, 0, 0));
1587                 }
1588         }
1589         snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry);
1590         script_set_env(prefix, "expiry", tbuf);
1591 }
1592
1593 void
1594 script_write_params(char *prefix, struct client_lease *lease)
1595 {
1596         size_t           fn_len = 0, sn_len = 0, pr_len = 0;
1597         struct imsg_hdr  hdr;
1598         struct buf      *buf;
1599         int              i;
1600
1601         if (lease->filename != NULL)
1602                 fn_len = strlen(lease->filename);
1603         if (lease->server_name != NULL)
1604                 sn_len = strlen(lease->server_name);
1605         if (prefix != NULL)
1606                 pr_len = strlen(prefix);
1607
1608         hdr.code = IMSG_SCRIPT_WRITE_PARAMS;
1609         hdr.len = sizeof(hdr) + sizeof(struct client_lease) +
1610             sizeof(size_t) + fn_len + sizeof(size_t) + sn_len +
1611             sizeof(size_t) + pr_len;
1612
1613         for (i = 0; i < 256; i++)
1614                 hdr.len += sizeof(int) + lease->options[i].len;
1615
1616         scripttime = time(NULL);
1617
1618         buf = buf_open(hdr.len);
1619
1620         buf_add(buf, &hdr, sizeof(hdr));
1621         buf_add(buf, lease, sizeof(struct client_lease));
1622         buf_add(buf, &fn_len, sizeof(fn_len));
1623         buf_add(buf, lease->filename, fn_len);
1624         buf_add(buf, &sn_len, sizeof(sn_len));
1625         buf_add(buf, lease->server_name, sn_len);
1626         buf_add(buf, &pr_len, sizeof(pr_len));
1627         buf_add(buf, prefix, pr_len);
1628
1629         for (i = 0; i < 256; i++) {
1630                 buf_add(buf, &lease->options[i].len,
1631                     sizeof(lease->options[i].len));
1632                 buf_add(buf, lease->options[i].data,
1633                     lease->options[i].len);
1634         }
1635
1636         buf_close(privfd, buf);
1637 }
1638
1639 int
1640 script_go(void)
1641 {
1642         struct imsg_hdr  hdr;
1643         struct buf      *buf;
1644         int              ret;
1645
1646         scripttime = time(NULL);
1647
1648         hdr.code = IMSG_SCRIPT_GO;
1649         hdr.len = sizeof(struct imsg_hdr);
1650
1651         buf = buf_open(hdr.len);
1652
1653         buf_add(buf, &hdr, sizeof(hdr));
1654         buf_close(privfd, buf);
1655
1656         bzero(&hdr, sizeof(hdr));
1657         buf_read(privfd, &hdr, sizeof(hdr));
1658         if (hdr.code != IMSG_SCRIPT_GO_RET)
1659                 error("unexpected msg type %u", hdr.code);
1660         if (hdr.len != sizeof(hdr) + sizeof(int))
1661                 error("received corrupted message");
1662         buf_read(privfd, &ret, sizeof(ret));
1663
1664         return (ret);
1665 }
1666
1667 int
1668 priv_script_go(void)
1669 {
1670         char *scriptName, *argv[2], **envp;
1671         int pid, wpid, wstatus;
1672
1673         scripttime = time(NULL);
1674
1675         scriptName = config->script_name;
1676         envp = client->scriptEnv;
1677
1678         argv[0] = scriptName;
1679         argv[1] = NULL;
1680
1681         pid = fork();
1682         if (pid < 0) {
1683                 error("fork: %m");
1684                 wstatus = 0;
1685         } else if (pid) {
1686                 do {
1687                         wpid = wait(&wstatus);
1688                 } while (wpid != pid && wpid > 0);
1689                 if (wpid < 0) {
1690                         error("wait: %m");
1691                         wstatus = 0;
1692                 }
1693         } else {
1694                 execve(scriptName, argv, envp);
1695                 error("execve (%s, ...): %m", scriptName);
1696         }
1697
1698         script_flush_env();
1699
1700         return (WEXITSTATUS(wstatus));
1701 }
1702
1703 void
1704 script_set_env(const char *prefix, const char *name, const char *value)
1705 {
1706         int i, j, namelen;
1707
1708         namelen = strlen(name);
1709
1710         for (i = 0; client->scriptEnv[i]; i++)
1711                 if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
1712                     client->scriptEnv[i][namelen] == '=')
1713                         break;
1714
1715         if (client->scriptEnv[i])
1716                 /* Reuse the slot. */
1717                 free(client->scriptEnv[i]);
1718         else {
1719                 /* New variable.  Expand if necessary. */
1720                 if (i >= client->scriptEnvsize - 1) {
1721                         char **newscriptEnv;
1722                         int newscriptEnvsize = client->scriptEnvsize + 50;
1723
1724                         newscriptEnv = realloc(client->scriptEnv,
1725                             newscriptEnvsize);
1726                         if (newscriptEnv == NULL) {
1727                                 free(client->scriptEnv);
1728                                 client->scriptEnv = NULL;
1729                                 client->scriptEnvsize = 0;
1730                                 error("script_set_env: no memory for variable");
1731                         }
1732                         client->scriptEnv = newscriptEnv;
1733                         client->scriptEnvsize = newscriptEnvsize;
1734                 }
1735                 /* need to set the NULL pointer at end of array beyond
1736                    the new slot. */
1737                 client->scriptEnv[i + 1] = NULL;
1738         }
1739         /* Allocate space and format the variable in the appropriate slot. */
1740         client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
1741             strlen(value) + 1);
1742         if (client->scriptEnv[i] == NULL)
1743                 error("script_set_env: no memory for variable assignment");
1744
1745         /* No `` or $() command substitution allowed in environment values! */
1746         for (j = 0; j < strlen(value); j++)
1747                 switch (value[j]) {
1748                 case '`':
1749                 case '$':
1750                         error("illegal character (%c) in value '%s'", value[j],
1751                             value);
1752                         /* not reached */
1753                 }
1754         snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1755             1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
1756 }
1757
1758 void
1759 script_flush_env(void)
1760 {
1761         int i;
1762
1763         for (i = 0; client->scriptEnv[i]; i++) {
1764                 free(client->scriptEnv[i]);
1765                 client->scriptEnv[i] = NULL;
1766         }
1767         client->scriptEnvsize = 0;
1768 }
1769
1770 int
1771 dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option)
1772 {
1773         size_t i;
1774
1775         for (i = 0; option->name[i]; i++) {
1776                 if (i + 1 == buflen)
1777                         return 0;
1778                 if (option->name[i] == '-')
1779                         buf[i] = '_';
1780                 else
1781                         buf[i] = option->name[i];
1782         }
1783
1784         buf[i] = 0;
1785         return 1;
1786 }
1787
1788 void
1789 go_daemon(void)
1790 {
1791         static int state = 0;
1792
1793         if (no_daemon || state)
1794                 return;
1795
1796         state = 1;
1797
1798         /* Stop logging to stderr... */
1799         log_perror = 0;
1800
1801         if (daemon(1, 0) == -1)
1802                 error("daemon");
1803
1804         /* we are chrooted, daemon(3) fails to open /dev/null */
1805         if (nullfd != -1) {
1806                 dup2(nullfd, STDIN_FILENO);
1807                 dup2(nullfd, STDOUT_FILENO);
1808                 dup2(nullfd, STDERR_FILENO);
1809                 close(nullfd);
1810                 nullfd = -1;
1811         }
1812 }
1813
1814 int
1815 check_option(struct client_lease *l, int option)
1816 {
1817         char *opbuf;
1818         char *sbuf;
1819
1820         /* we use this, since this is what gets passed to dhclient-script */
1821
1822         opbuf = pretty_print_option(option, l->options[option].data,
1823             l->options[option].len, 0, 0);
1824
1825         sbuf = option_as_string(option, l->options[option].data,
1826             l->options[option].len);
1827
1828         switch (option) {
1829         case DHO_SUBNET_MASK:
1830         case DHO_SWAP_SERVER:
1831         case DHO_BROADCAST_ADDRESS:
1832         case DHO_DHCP_SERVER_IDENTIFIER:
1833         case DHO_ROUTER_SOLICITATION_ADDRESS:
1834         case DHO_DHCP_REQUESTED_ADDRESS:
1835                 if (ipv4addrs(opbuf) == 0) {
1836                         warning("Invalid IP address in option %s: %s",
1837                             dhcp_options[option].name, opbuf);
1838                         return (0);
1839                 }
1840                 if (l->options[option].len != 4) { /* RFC 2132 */
1841                         warning("warning: Only 1 IP address allowed in "
1842                             "%s option; length %d, must be 4",
1843                             dhcp_options[option].name,
1844                             l->options[option].len);
1845                         l->options[option].len = 4;
1846                 }
1847                 return (1);
1848         case DHO_TIME_SERVERS:
1849         case DHO_NAME_SERVERS:
1850         case DHO_ROUTERS:
1851         case DHO_DOMAIN_NAME_SERVERS:
1852         case DHO_LOG_SERVERS:
1853         case DHO_COOKIE_SERVERS:
1854         case DHO_LPR_SERVERS:
1855         case DHO_IMPRESS_SERVERS:
1856         case DHO_RESOURCE_LOCATION_SERVERS:
1857         case DHO_NIS_SERVERS:
1858         case DHO_NTP_SERVERS:
1859         case DHO_NETBIOS_NAME_SERVERS:
1860         case DHO_NETBIOS_DD_SERVER:
1861         case DHO_FONT_SERVERS:
1862                 if (ipv4addrs(opbuf) == 0) {
1863                         warning("Invalid IP address in option %s: %s",
1864                             dhcp_options[option].name, opbuf);
1865                         return (0);
1866                 }
1867                 return (1);
1868         case DHO_HOST_NAME:
1869         case DHO_DOMAIN_NAME:
1870         case DHO_NIS_DOMAIN:
1871                 if (!res_hnok(sbuf)) {
1872                         warning("Bogus Host Name option %d: %s (%s)", option,
1873                             sbuf, opbuf);
1874                         l->options[option].len = 0;
1875                         free(l->options[option].data);
1876                 }
1877                 return (1);
1878         case DHO_PAD:
1879         case DHO_TIME_OFFSET:
1880         case DHO_BOOT_SIZE:
1881         case DHO_MERIT_DUMP:
1882         case DHO_ROOT_PATH:
1883         case DHO_EXTENSIONS_PATH:
1884         case DHO_IP_FORWARDING:
1885         case DHO_NON_LOCAL_SOURCE_ROUTING:
1886         case DHO_POLICY_FILTER:
1887         case DHO_MAX_DGRAM_REASSEMBLY:
1888         case DHO_DEFAULT_IP_TTL:
1889         case DHO_PATH_MTU_AGING_TIMEOUT:
1890         case DHO_PATH_MTU_PLATEAU_TABLE:
1891         case DHO_INTERFACE_MTU:
1892         case DHO_ALL_SUBNETS_LOCAL:
1893         case DHO_PERFORM_MASK_DISCOVERY:
1894         case DHO_MASK_SUPPLIER:
1895         case DHO_ROUTER_DISCOVERY:
1896         case DHO_STATIC_ROUTES:
1897         case DHO_TRAILER_ENCAPSULATION:
1898         case DHO_ARP_CACHE_TIMEOUT:
1899         case DHO_IEEE802_3_ENCAPSULATION:
1900         case DHO_DEFAULT_TCP_TTL:
1901         case DHO_TCP_KEEPALIVE_INTERVAL:
1902         case DHO_TCP_KEEPALIVE_GARBAGE:
1903         case DHO_VENDOR_ENCAPSULATED_OPTIONS:
1904         case DHO_NETBIOS_NODE_TYPE:
1905         case DHO_NETBIOS_SCOPE:
1906         case DHO_X_DISPLAY_MANAGER:
1907         case DHO_DHCP_LEASE_TIME:
1908         case DHO_DHCP_OPTION_OVERLOAD:
1909         case DHO_DHCP_MESSAGE_TYPE:
1910         case DHO_DHCP_PARAMETER_REQUEST_LIST:
1911         case DHO_DHCP_MESSAGE:
1912         case DHO_DHCP_MAX_MESSAGE_SIZE:
1913         case DHO_DHCP_RENEWAL_TIME:
1914         case DHO_DHCP_REBINDING_TIME:
1915         case DHO_DHCP_CLASS_IDENTIFIER:
1916         case DHO_DHCP_CLIENT_IDENTIFIER:
1917         case DHO_DHCP_USER_CLASS_ID:
1918         case DHO_TFTP_SERVER:
1919         case DHO_END:
1920                 return (1);
1921         default:
1922                 warning("unknown dhcp option value 0x%x", option);
1923                 return (unknown_ok);
1924         }
1925 }
1926
1927 int
1928 res_hnok(const char *name)
1929 {
1930         const char *dn = name;
1931         int pch = '.', ch = *dn++;
1932         int warn = 0;
1933
1934         while (ch != '\0') {
1935                 int nch = *dn++;
1936
1937                 if (ch == '.') {
1938                         ;
1939                 } else if (pch == '.' || nch == '.' || nch == '\0') {
1940                         if (!isalnum(ch))
1941                                 return (0);
1942                 } else if (!isalnum(ch) && ch != '-' && ch != '_')
1943                                 return (0);
1944                 else if (ch == '_' && warn == 0) {
1945                         warning("warning: hostname %s contains an "
1946                             "underscore which violates RFC 952", name);
1947                         warn++;
1948                 }
1949                 pch = ch, ch = nch;
1950         }
1951         return (1);
1952 }
1953
1954 /* Does buf consist only of dotted decimal ipv4 addrs?
1955  * return how many if so,
1956  * otherwise, return 0
1957  */
1958 int
1959 ipv4addrs(char * buf)
1960 {
1961         struct in_addr jnk;
1962         int count = 0;
1963
1964         while (inet_aton(buf, &jnk) == 1){
1965                 count++;
1966                 while (*buf == '.' || isdigit(*buf))
1967                         buf++;
1968                 if (*buf == '\0')
1969                         return (count);
1970                 while (*buf ==  ' ')
1971                         buf++;
1972         }
1973         return (0);
1974 }
1975
1976 char *
1977 option_as_string(unsigned int code, unsigned char *data, int len)
1978 {
1979         static char optbuf[32768]; /* XXX */
1980         char *op = optbuf;
1981         int opleft = sizeof(optbuf);
1982         unsigned char *dp = data;
1983
1984         if (code > 255)
1985                 error("option_as_string: bad code %d", code);
1986
1987         for (; dp < data + len; dp++) {
1988                 if (!isascii(*dp) || !isprint(*dp)) {
1989                         if (dp + 1 != data + len || *dp != 0) {
1990                                 size_t oplen;
1991                                 snprintf(op, opleft, "\\%03o", *dp);
1992                                 oplen = strlen(op);
1993                                 op += oplen;
1994                                 opleft -= oplen;
1995                         }
1996                 } else if (*dp == '"' || *dp == '\'' || *dp == '$' ||
1997                     *dp == '`' || *dp == '\\') {
1998                         *op++ = '\\';
1999                         *op++ = *dp;
2000                         opleft -= 2;
2001                 } else {
2002                         *op++ = *dp;
2003                         opleft--;
2004                 }
2005         }
2006         if (opleft < 1)
2007                 goto toobig;
2008         *op = 0;
2009         return optbuf;
2010 toobig:
2011         warning("dhcp option too large");
2012         return "<error>";
2013 }
2014
2015 int
2016 fork_privchld(int fd, int fd2)
2017 {
2018         struct pollfd pfd[1];
2019         int nfds, pfail = 0;
2020
2021         switch (fork()) {
2022         case -1:
2023                 error("cannot fork");
2024                 break;
2025         case 0:
2026                 break;
2027         default:
2028                 return (0);
2029         }
2030
2031         if (chdir("/") == -1)
2032                 error("chdir(\"/\")");
2033
2034         setproctitle("%s [priv]", ifi->name);
2035
2036         dup2(nullfd, STDIN_FILENO);
2037         dup2(nullfd, STDOUT_FILENO);
2038         dup2(nullfd, STDERR_FILENO);
2039         close(nullfd);
2040         close(fd2);
2041
2042         for (;;) {
2043                 pfd[0].fd = fd;
2044                 pfd[0].events = POLLIN;
2045                 if ((nfds = poll(pfd, 1, INFTIM)) == -1)
2046                         if (errno != EINTR)
2047                                 error("poll error");
2048
2049                 /*
2050                  * Handle temporary errors, but bail if they persist.
2051                  */
2052                 if (nfds == 0 || !(pfd[0].revents & POLLIN)) {
2053                         if (pfail > POLL_FAILURES)
2054                                 error("poll failed > %d times", POLL_FAILURES);
2055                         sleep(pfail * POLL_FAILURE_WAIT);
2056                         pfail++;
2057                         continue;
2058                 }
2059
2060                 dispatch_imsg(fd);
2061         }
2062 }
2063
2064 void
2065 get_ifname(char *ifname, char *arg)
2066 {
2067         struct ifgroupreq ifgr;
2068         struct ifg_req *ifg;
2069         int s, len;
2070
2071         if (!strcmp(arg, "egress")) {
2072                 s = socket(AF_INET, SOCK_DGRAM, 0);
2073                 if (s == -1)
2074                         error("socket error");
2075                 bzero(&ifgr, sizeof(ifgr));
2076                 strlcpy(ifgr.ifgr_name, "egress", sizeof(ifgr.ifgr_name));
2077                 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) {
2078                         if (errno == ENOENT)
2079                                 error("no interface in group egress found");
2080                         error("ioctl SIOCGIFGMEMB: %m");
2081                 }
2082                 len = ifgr.ifgr_len;
2083                 if ((ifgr.ifgr_groups = calloc(1, len)) == NULL)
2084                         error("get_ifname");
2085                 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1)
2086                         error("ioctl SIOCGIFGMEMB: %m");
2087
2088                 arg = NULL;
2089                 for (ifg = ifgr.ifgr_groups;
2090                      ifg && len >= sizeof(struct ifg_req); ifg++) {
2091                         len -= sizeof(struct ifg_req);
2092                         if (arg)
2093                                 error("too many interfaces in group egress");
2094                         arg = ifg->ifgrq_member;
2095                 }
2096
2097                 if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2098                         error("Interface name too long: %m");
2099
2100                 free(ifgr.ifgr_groups);
2101                 close(s);
2102         } else if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2103                 error("Interface name too long");
2104 }