sbin/dhclient/dhclient.c

   1 /*      $OpenBSD: src/sbin/dhclient/dhclient.c,v 1.155 2012/09/17 20:30:17 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 char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
  72 char *path_dhclient_db = NULL;
  73
  74 int log_perror = 1;
  75 int privfd;
  76 int nullfd = -1;
  77 int no_daemon;
  78 int unknown_ok = 1;
  79 int routefd = -1;
  80
  81 struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
  82 struct in_addr inaddr_any;
  83 struct sockaddr_in sockaddr_broadcast;
  84
  85 struct interface_info *ifi;
  86 struct client_state *client;
  87 struct client_config *config;
  88
  89 int              findproto(char *, int);
  90 struct sockaddr *get_ifa(char *, int);
  91 void             usage(void);
  92 int              check_option(struct client_lease *l, int option);
  93 int              ipv4addrs(char * buf);
  94 int              res_hnok(const char *dn);
  95 char            *option_as_string(unsigned int code, unsigned char *data, int len);
  96 int              fork_privchld(int, int);
  97 void             get_ifname(char *, char *);
  98
  99 time_t  scripttime;
 100 static FILE *leaseFile;
 101
 102 int
 103 findproto(char *cp, int n)
 104 {
 105         struct sockaddr *sa;
 106         int i;
 107
 108         if (n == 0)
 109                 return -1;
 110         for (i = 1; i; i <<= 1) {
 111                 if (i & n) {
 112                         sa = (struct sockaddr *)cp;
 113                         switch (i) {
 114                         case RTA_IFA:
 115                         case RTA_DST:
 116                         case RTA_GATEWAY:
 117                         case RTA_NETMASK:
 118                                 if (sa->sa_family == AF_INET)
 119                                         return AF_INET;
 120                                 if (sa->sa_family == AF_INET6)
 121                                         return AF_INET6;
 122                                 break;
 123                         case RTA_IFP:
 124                                 break;
 125                         }
 126                         RT_ADVANCE(cp, sa);
 127                 }
 128         }
 129         return (-1);
 130 }
 131
 132 struct sockaddr *
 133 get_ifa(char *cp, int n)
 134 {
 135         struct sockaddr *sa;
 136         int i;
 137
 138         if (n == 0)
 139                 return (NULL);
 140         for (i = 1; i; i <<= 1)
 141                 if (i & n) {
 142                         sa = (struct sockaddr *)cp;
 143                         if (i == RTA_IFA)
 144                                 return (sa);
 145                         RT_ADVANCE(cp, sa);
 146                 }
 147
 148         return (NULL);
 149 }
 150 struct iaddr defaddr = { .len = 4 }; /* NULL is for silence warnings */
 151
 152 void
 153 routehandler(void)
 154 {
 155         int linkstat;
 156         char msg[2048];
 157         struct rt_msghdr *rtm;
 158         struct if_msghdr *ifm;
 159         struct ifa_msghdr *ifam;
 160         struct if_announcemsghdr *ifan;
 161         struct client_lease *l;
 162         struct sockaddr *sa;
 163         struct iaddr a;
 164         ssize_t n;
 165         char *errmsg, buf[64];
 166
 167         do {
 168                 n = read(routefd, &msg, sizeof(msg));
 169         } while (n == -1 && errno == EINTR);
 170
 171         rtm = (struct rt_msghdr *)msg;
 172         if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen ||
 173             rtm->rtm_version != RTM_VERSION)
 174                 return;
 175
 176         switch (rtm->rtm_type) {
 177         case RTM_NEWADDR:
 178                 ifam = (struct ifa_msghdr *)rtm;
 179                 if (ifam->ifam_index != ifi->index)
 180                         break;
 181                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
 182                         break;
 183                 sa = get_ifa((char *)(ifam + 1), ifam->ifam_addrs);
 184                 if (sa == NULL) {
 185                         errmsg = "sa == NULL";
 186                         goto die;
 187                 }
 188
 189                 if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf))
 190                         error("king bula sez: len mismatch");
 191                 memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len);
 192                 if (addr_eq(a, defaddr))
 193                         break;
 194
 195                 /* state_panic() can try unexpired existing leases */
 196                 if (client->active && addr_eq(a, client->active->address))
 197                         break;
 198                 for (l = client->leases; l != NULL; l = l->next)
 199                         if (addr_eq(a, l->address))
 200                                 break;
 201
 202                 if (l != NULL)
 203                         /* new addr is the one we set */
 204                         break;
 205                 snprintf(buf, sizeof(buf), "%s: %s",
 206                     "new address not one we set", piaddr(a));
 207                 errmsg = buf;
 208                 goto die;
 209         case RTM_DELADDR:
 210                 ifam = (struct ifa_msghdr *)rtm;
 211                 if (ifam->ifam_index != ifi->index)
 212                         break;
 213                 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
 214                         break;
 215                 /* XXX check addrs like RTM_NEWADDR instead of this? */
 216                 if (scripttime == 0 || time(NULL) < scripttime + 10)
 217                         break;
 218                 errmsg = "interface address deleted";
 219                 goto die;
 220         case RTM_IFINFO:
 221                 ifm = (struct if_msghdr *)rtm;
 222                 if (ifm->ifm_index != ifi->index)
 223                         break;
 224                 if ((rtm->rtm_flags & RTF_UP) == 0) {
 225                         errmsg = "interface down";
 226                         goto die;
 227                 }
 228
 229                 linkstat =
 230                     LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0;
 231                 if (linkstat != ifi->linkstat) {
 232 #ifdef DEBUG
 233                         debug("link state %s -> %s",
 234                             ifi->linkstat ? "up" : "down",
 235                             linkstat ? "up" : "down");
 236 #endif
 237                         ifi->linkstat = interface_status(ifi->name);
 238                         if (ifi->linkstat) {
 239                                 client->state = S_REBOOTING;
 240                                 state_reboot();
 241                         } else if (client->active) {
 242                                 script_init("FAIL");
 243                                 script_write_params("old_", client->active);
 244                                 script_go();
 245                         }
 246                 }
 247                 break;
 248         case RTM_IFANNOUNCE:
 249                 ifan = (struct if_announcemsghdr *)rtm;
 250                 if (ifan->ifan_what == IFAN_DEPARTURE &&
 251                     ifan->ifan_index == ifi->index) {
 252                         errmsg = "interface departure";
 253                         goto die;
 254                 }
 255                 break;
 256         default:
 257                 break;
 258         }
 259         return;
 260
 261 die:
 262         script_init("FAIL");
 263         script_write_params("old_", client->active);
 264         script_go();
 265         sleep(2);
 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
 326         memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
 327         sockaddr_broadcast.sin_family = AF_INET;
 328         sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
 329         sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
 330         sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
 331         inaddr_any.s_addr = INADDR_ANY;
 332
 333         read_client_conf();
 334
 335         if (interface_status(ifi->name) == 0) {
 336                 interface_link_forceup(ifi->name);
 337                 /* Give it up to 4 seconds of silent grace to find link */
 338                 i = -4;
 339         } else
 340                 i = 0;
 341
 342         while (!(ifi->linkstat = interface_status(ifi->name))) {
 343                 if (i == 0)
 344                         fprintf(stderr, "%s: no link ...", ifi->name);
 345                 else if (i > 0)
 346                         fprintf(stderr, ".");
 347                 fflush(stderr);
 348                 if (++i > config->link_timeout) {
 349                         fprintf(stderr, " sleeping\n");
 350                         goto dispatch;
 351                 }
 352                 sleep(1);
 353         }
 354         if (i > 0)
 355                 fprintf(stderr, " got link\n");
 356
 357  dispatch:
 358         if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
 359                 error("cannot open %s: %m", _PATH_DEVNULL);
 360
 361         if ((pw = getpwnam("_dhcp")) == NULL)
 362                 error("no such user: _dhcp");
 363
 364         if (pipe(pipe_fd) == -1)
 365                 error("pipe");
 366
 367         fork_privchld(pipe_fd[0], pipe_fd[1]);
 368
 369         close(pipe_fd[0]);
 370         privfd = pipe_fd[1];
 371
 372         if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1)
 373                 error("can't open and lock %s: %m", path_dhclient_db);
 374         read_client_leases();
 375         if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL)
 376                 error("can't open %s: %m", path_dhclient_db);
 377         rewrite_client_leases();
 378         close(fd);
 379
 380         if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1)
 381                 error("socket(PF_ROUTE, SOCK_RAW): %m");
 382
 383         /* set up the interface */
 384         discover_interface();
 385
 386         if (chroot(_PATH_VAREMPTY) == -1)
 387                 error("chroot");
 388         if (chdir("/") == -1)
 389                 error("chdir(\"/\")");
 390
 391         if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
 392                 error("setresgid");
 393         if (setgroups(1, &pw->pw_gid) == -1)
 394                 error("setgroups");
 395         if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
 396                 error("setresuid");
 397
 398         endpwent();
 399
 400         setproctitle("%s", ifi->name);
 401
 402         if (ifi->linkstat) {
 403                 client->state = S_REBOOTING;
 404                 state_reboot();
 405         } else
 406                 go_daemon();
 407
 408         dispatch();
 409
 410         /* not reached */
 411         return (0);
 412 }
 413
 414 void
 415 usage(void)
 416 {
 417         fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n",
 418             getprogname());
 419         exit(1);
 420 }
 421
 422 /*
 423  * Individual States:
 424  *
 425  * Each routine is called from the dhclient_state_machine() in one of
 426  * these conditions:
 427  * -> entering INIT state
 428  * -> recvpacket_flag == 0: timeout in this state
 429  * -> otherwise: received a packet in this state
 430  *
 431  * Return conditions as handled by dhclient_state_machine():
 432  * Returns 1, sendpacket_flag = 1: send packet, reset timer.
 433  * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
 434  * Returns 0: finish the nap which was interrupted for no good reason.
 435  *
 436  * Several per-interface variables are used to keep track of the process:
 437  *   active_lease: the lease that is being used on the interface
 438  *                 (null pointer if not configured yet).
 439  *   offered_leases: leases corresponding to DHCPOFFER messages that have
 440  *                   been sent to us by DHCP servers.
 441  *   acked_leases: leases corresponding to DHCPACK messages that have been
 442  *                 sent to us by DHCP servers.
 443  *   sendpacket: DHCP packet we're trying to send.
 444  *   destination: IP address to send sendpacket to
 445  * In addition, there are several relevant per-lease variables.
 446  *   T1_expiry, T2_expiry, lease_expiry: lease milestones
 447  * In the active lease, these control the process of renewing the lease;
 448  * In leases on the acked_leases list, this simply determines when we
 449  * can no longer legitimately use the lease.
 450  */
 451 void
 452 state_reboot(void)
 453 {
 454         /* Cancel all timeouts, since a link state change gets us here
 455            and can happen anytime. */
 456         cancel_timeout();
 457
 458         /* If we don't remember an active lease, go straight to INIT. */
 459         if (!client->active || client->active->is_bootp) {
 460                 client->state = S_INIT;
 461                 state_init();
 462                 return;
 463         }
 464
 465         /* make_request doesn't initialize xid because it normally comes
 466            from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
 467            so pick an xid now. */
 468         client->xid = arc4random();
 469
 470         /* Make a DHCPREQUEST packet, and set appropriate per-interface
 471            flags. */
 472         make_request(client->active);
 473         client->destination = iaddr_broadcast;
 474         client->first_sending = time(NULL);
 475         client->interval = 0;
 476
 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 = time(NULL);
 494         client->interval = 0;
 495
 496         send_discover();
 497 }
 498
 499 /*
 500  * state_selecting is called when one or more DHCPOFFER packets
 501  * have been received and a configurable period of time has passed.
 502  */
 503 void
 504 state_selecting(void)
 505 {
 506         struct client_lease *lp, *next, *picked;
 507         time_t cur_time;
 508
 509         /* Cancel state_selecting and send_discover timeouts, since either
 510            one could have got us here. */
 511         cancel_timeout();
 512
 513         /* We have received one or more DHCPOFFER packets.   Currently,
 514            the only criterion by which we judge leases is whether or
 515            not we get a response when we arp for them. */
 516         picked = NULL;
 517         for (lp = client->offered_leases; lp; lp = next) {
 518                 next = lp->next;
 519
 520                 if (!picked) {
 521                         picked = lp;
 522                 } else {
 523                         make_decline(lp);
 524                         send_decline();
 525                         free_client_lease(lp);
 526                 }
 527         }
 528         client->offered_leases = NULL;
 529
 530         /* If we just tossed all the leases we were offered, go back
 531            to square one. */
 532         if (!picked) {
 533                 client->state = S_INIT;
 534                 state_init();
 535                 return;
 536         }
 537         picked->next = NULL;
 538
 539         time(&cur_time);
 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         send_request();
 572 }
 573
 574 void
 575 dhcpack(struct iaddr client_addr, struct option_data *options)
 576 {
 577         struct client_lease *lease;
 578         time_t cur_time;
 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();
 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         time(&cur_time);
 630
 631         client->new->expiry += cur_time;
 632         /* Lease lengths can never be negative. */
 633         if (client->new->expiry < cur_time)
 634                 client->new->expiry = TIME_MAX;
 635         client->new->renewal += cur_time;
 636         if (client->new->renewal < cur_time)
 637                 client->new->renewal = TIME_MAX;
 638         client->new->rebind += cur_time;
 639         if (client->new->rebind < cur_time)
 640                 client->new->rebind = TIME_MAX;
 641
 642         bind_lease();
 643 }
 644
 645 void
 646 bind_lease(void)
 647 {
 648         /* Run the client script with the new parameters. */
 649         script_init((client->state == S_REQUESTING ? "BOUND" :
 650             (client->state == S_RENEWING ? "RENEW" :
 651                 (client->state == S_REBOOTING ? "REBOOT" : "REBIND"))));
 652         if (client->active && client->state != S_REBOOTING)
 653                 script_write_params("old_", client->active);
 654         script_write_params("new_", client->new);
 655         script_go();
 656
 657         /* Replace the old active lease with the new one. */
 658         if (client->active)
 659                 free_client_lease(client->active);
 660         client->active = client->new;
 661         client->new = NULL;
 662
 663         /* Write out new leases file. */
 664         rewrite_client_leases();
 665
 666         /* Set timeout to start the renewal process. */
 667         set_timeout(client->active->renewal, state_bound);
 668
 669         note("bound to %s -- renewal in %lld seconds.",
 670             piaddr(client->active->address),
 671             (long long)(client->active->renewal - time(NULL)));
 672         client->state = S_BOUND;
 673         go_daemon();
 674 }
 675
 676 /*
 677  * state_bound is called when we've successfully bound to a particular
 678  * lease, but the renewal time on that lease has expired.   We are
 679  * expected to unicast a DHCPREQUEST to the server that gave us our
 680  * original lease.
 681  */
 682 void
 683 state_bound(void)
 684 {
 685         /* T1 has expired. */
 686         make_request(client->active);
 687         client->xid = client->packet.xid;
 688
 689         if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
 690                 memcpy(client->destination.iabuf,
 691                     client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data,
 692                     4);
 693                 client->destination.len = 4;
 694         } else
 695                 client->destination = iaddr_broadcast;
 696
 697         client->first_sending = time(NULL);
 698         client->interval = 0;
 699         client->state = S_RENEWING;
 700
 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         time_t 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 <= time(NULL))
 776                 state_selecting();
 777         else {
 778                 set_timeout(stop_selecting, state_selecting);
 779         }
 780 }
 781
 782 /*
 783  * Allocate a client_lease structure and initialize it from the
 784  * parameters in the specified packet.
 785  */
 786 struct client_lease *
 787 packet_to_lease(struct option_data *options)
 788 {
 789         struct client_lease *lease;
 790         int i;
 791
 792         lease = malloc(sizeof(struct client_lease));
 793
 794         if (!lease) {
 795                 warning("dhcpoffer: no memory to record lease.");
 796                 return (NULL);
 797         }
 798
 799         memset(lease, 0, sizeof(*lease));
 800
 801         /* Copy the lease options. */
 802         for (i = 0; i < 256; i++) {
 803                 if (options[i].len) {
 804                         lease->options[i] = options[i];
 805                         options[i].data = NULL;
 806                         options[i].len = 0;
 807                         if (!check_option(lease, i)) {
 808                                 warning("Invalid lease option - ignoring offer");
 809                                 free_client_lease(lease);
 810                                 return (NULL);
 811                         }
 812                 }
 813         }
 814
 815         lease->address.len = sizeof(client->packet.yiaddr);
 816         memcpy(lease->address.iabuf, &client->packet.yiaddr,
 817             lease->address.len);
 818
 819         /* If the server name was filled out, copy it. */
 820         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
 821             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
 822             client->packet.sname[0]) {
 823                 lease->server_name = malloc(DHCP_SNAME_LEN + 1);
 824                 if (!lease->server_name) {
 825                         warning("dhcpoffer: no memory for server name.");
 826                         free_client_lease(lease);
 827                         return (NULL);
 828                 }
 829                 memcpy(lease->server_name, client->packet.sname,
 830                     DHCP_SNAME_LEN);
 831                 lease->server_name[DHCP_SNAME_LEN] = '\0';
 832                 if (!res_hnok(lease->server_name)) {
 833                         warning("Bogus server name %s", lease->server_name);
 834                         free(lease->server_name);
 835                         lease->server_name = NULL;
 836                 }
 837         }
 838
 839         /* Ditto for the filename. */
 840         if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
 841             !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) &&
 842             client->packet.file[0]) {
 843                 /* Don't count on the NUL terminator. */
 844                 lease->filename = malloc(DHCP_FILE_LEN + 1);
 845                 if (!lease->filename) {
 846                         warning("dhcpoffer: no memory for filename.");
 847                         free_client_lease(lease);
 848                         return (NULL);
 849                 }
 850                 memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN);
 851                 lease->filename[DHCP_FILE_LEN] = '\0';
 852         }
 853         return lease;
 854 }
 855
 856 void
 857 dhcpnak(struct iaddr client_addr, struct option_data *options)
 858 {
 859
 860         if (client->state != S_REBOOTING &&
 861             client->state != S_REQUESTING &&
 862             client->state != S_RENEWING &&
 863             client->state != S_REBINDING)
 864                 return;
 865
 866
 867         if (!client->active) {
 868                 note("DHCPNAK with no active lease.");
 869                 return;
 870         }
 871
 872         free_client_lease(client->active);
 873         client->active = NULL;
 874
 875         /* Stop sending DHCPREQUEST packets... */
 876         cancel_timeout();
 877
 878         client->state = S_INIT;
 879         state_init();
 880 }
 881
 882 /*
 883  * Send out a DHCPDISCOVER packet, and set a timeout to send out another
 884  * one after the right interval has expired.  If we don't get an offer by
 885  * the time we reach the panic interval, call the panic function.
 886  */
 887 void
 888 send_discover(void)
 889 {
 890         time_t cur_time;
 891         int interval, increase = 1;
 892
 893         time(&cur_time);
 894
 895         /* Figure out how long it's been since we started transmitting. */
 896         interval = cur_time - client->first_sending;
 897
 898         /* If we're past the panic timeout, call the script and tell it
 899            we haven't found anything for this interface yet. */
 900         if (interval > config->timeout) {
 901                 state_panic();
 902                 return;
 903         }
 904
 905         /*
 906          * If we're supposed to increase the interval, do so.  If it's
 907          * currently zero (i.e., we haven't sent any packets yet), set
 908          * it to initial_interval; otherwise, add to it a random
 909          * number between zero and two times itself.  On average, this
 910          * means that it will double with every transmission.
 911          */
 912         if (increase) {
 913                 if (!client->interval)
 914                         client->interval = config->initial_interval;
 915                 else {
 916                         client->interval += (arc4random() >> 2) %
 917                             (2 * client->interval);
 918                 }
 919
 920                 /* Don't backoff past cutoff. */
 921                 if (client->interval > config->backoff_cutoff)
 922                         client->interval = ((config->backoff_cutoff / 2)
 923                                  + ((arc4random() >> 2) %
 924                                     config->backoff_cutoff));
 925         } else if (!client->interval)
 926                 client->interval = config->initial_interval;
 927
 928         /* If the backoff would take us to the panic timeout, just use that
 929            as the interval. */
 930         if (cur_time + client->interval >
 931             client->first_sending + config->timeout)
 932                 client->interval = (client->first_sending +
 933                          config->timeout) - cur_time + 1;
 934
 935         /* Record the number of seconds since we started sending. */
 936         if (interval < 65536)
 937                 client->packet.secs = htons(interval);
 938         else
 939                 client->packet.secs = htons(65535);
 940         client->secs = client->packet.secs;
 941
 942         note("DHCPDISCOVER on %s to %s port %d interval %ld",
 943             ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr),
 944             ntohs(sockaddr_broadcast.sin_port), client->interval);
 945
 946         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
 947
 948         set_timeout_interval(client->interval, send_discover);
 949 }
 950
 951 /*
 952  * state_panic gets called if we haven't received any offers in a preset
 953  * amount of time.   When this happens, we try to use existing leases
 954  * that haven't yet expired, and failing that, we call the client script
 955  * and hope it can do something.
 956  */
 957 void
 958 state_panic(void)
 959 {
 960         struct client_lease *loop = client->active;
 961         struct client_lease *lp;
 962         time_t cur_time;
 963
 964         note("No DHCPOFFERS received.");
 965
 966         /* We may not have an active lease, but we may have some
 967            predefined leases that we can try. */
 968         if (!client->active && client->leases)
 969                 goto activate_next;
 970
 971         /* Run through the list of leases and see if one can be used. */
 972         time(&cur_time);
 973         while (client->active) {
 974                 if (client->active->expiry > cur_time) {
 975                         note("Trying recorded lease %s",
 976                             piaddr(client->active->address));
 977                         /* Run the client script with the existing
 978                            parameters. */
 979                         script_init("TIMEOUT");
 980                         script_write_params("new_", client->active);
 981
 982                         /* If the old lease is still good and doesn't
 983                            yet need renewal, go into BOUND state and
 984                            timeout at the renewal time. */
 985                         if (!script_go()) {
 986                                 if (cur_time < client->active->renewal) {
 987                                         client->state = S_BOUND;
 988                                         note("bound: renewal in %lld seconds.",
 989                                             (long long)(client->active->renewal
 990                                             - cur_time));
 991                                         set_timeout(client->active->renewal,
 992                                             state_bound);
 993                                 } else {
 994                                         client->state = S_BOUND;
 995                                         note("bound: immediate renewal.");
 996                                         state_bound();
 997                                 }
 998                                 go_daemon();
 999                                 return;
1000                         }
1001                 }
1002
1003                 /* If there are no other leases, give up. */
1004                 if (!client->leases) {
1005                         client->leases = client->active;
1006                         client->active = NULL;
1007                         break;
1008                 }
1009
1010 activate_next:
1011                 /* Otherwise, put the active lease at the end of the
1012                    lease list, and try another lease.. */
1013                 for (lp = client->leases; lp->next; lp = lp->next)
1014                         ;
1015                 lp->next = client->active;
1016                 if (lp->next)
1017                         lp->next->next = NULL;
1018                 client->active = client->leases;
1019                 client->leases = client->leases->next;
1020
1021                 /* If we already tried this lease, we've exhausted the
1022                    set of leases, so we might as well give up for
1023                    now. */
1024                 if (client->active == loop)
1025                         break;
1026                 else if (!loop)
1027                         loop = client->active;
1028         }
1029
1030         /* No leases were available, or what was available didn't work, so
1031            tell the shell script that we failed to allocate an address,
1032            and try again later. */
1033         note("No working leases in persistent database - sleeping.");
1034         script_init("FAIL");
1035         script_go();
1036         client->state = S_INIT;
1037         set_timeout_interval(config->retry_interval, state_init);
1038         go_daemon();
1039 }
1040
1041 void
1042 send_request(void)
1043 {
1044         struct sockaddr_in destination;
1045         struct in_addr from;
1046         time_t cur_time;
1047         int interval;
1048
1049         time(&cur_time);
1050
1051         /* Figure out how long it's been since we started transmitting. */
1052         interval = (int)(cur_time - client->first_sending);
1053
1054         /* If we're in the INIT-REBOOT or REQUESTING state and we're
1055            past the reboot timeout, go to INIT and see if we can
1056            DISCOVER an address... */
1057         /* XXX In the INIT-REBOOT state, if we don't get an ACK, it
1058            means either that we're on a network with no DHCP server,
1059            or that our server is down.  In the latter case, assuming
1060            that there is a backup DHCP server, DHCPDISCOVER will get
1061            us a new address, but we could also have successfully
1062            reused our old address.  In the former case, we're hosed
1063            anyway.  This is not a win-prone situation. */
1064         if ((client->state == S_REBOOTING ||
1065             client->state == S_REQUESTING) &&
1066             interval > config->reboot_timeout) {
1067                 client->state = S_INIT;
1068                 cancel_timeout();
1069                 state_init();
1070                 return;
1071         }
1072
1073         /* If the lease has expired, relinquish the address and go back
1074            to the INIT state. */
1075         if (client->state != S_REQUESTING &&
1076             cur_time > client->active->expiry) {
1077                 /* Run the client script with the new parameters. */
1078                 script_init("EXPIRE");
1079                 script_write_params("old_", client->active);
1080                 script_go();
1081
1082                 client->state = S_INIT;
1083                 state_init();
1084                 return;
1085         }
1086
1087         /* Do the exponential backoff... */
1088         if (!client->interval)
1089                 client->interval = config->initial_interval;
1090         else
1091                 client->interval += ((arc4random() >> 2) %
1092                     (2 * client->interval));
1093
1094         /* Don't backoff past cutoff. */
1095         if (client->interval > config->backoff_cutoff)
1096                 client->interval = ((config->backoff_cutoff / 2) +
1097                     ((arc4random() >> 2) % client->interval));
1098
1099         /* If the backoff would take us to the expiry time, just set the
1100            timeout to the expiry time. */
1101         if (client->state != S_REQUESTING && cur_time + client->interval >
1102             client->active->expiry)
1103                 client->interval = client->active->expiry - cur_time + 1;
1104
1105         /* If the lease T2 time has elapsed, or if we're not yet bound,
1106            broadcast the DHCPREQUEST rather than unicasting. */
1107         memset(&destination, 0, sizeof(destination));
1108         if (client->state == S_REQUESTING ||
1109             client->state == S_REBOOTING ||
1110             cur_time > client->active->rebind)
1111                 destination.sin_addr.s_addr = INADDR_BROADCAST;
1112         else
1113                 memcpy(&destination.sin_addr.s_addr, client->destination.iabuf,
1114                     sizeof(destination.sin_addr.s_addr));
1115         destination.sin_port = htons(REMOTE_PORT);
1116         destination.sin_family = AF_INET;
1117         destination.sin_len = sizeof(destination);
1118
1119         if (client->state != S_REQUESTING)
1120                 memcpy(&from, client->active->address.iabuf, sizeof(from));
1121         else
1122                 from.s_addr = INADDR_ANY;
1123
1124         /* Record the number of seconds since we started sending. */
1125         if (client->state == S_REQUESTING)
1126                 client->packet.secs = client->secs;
1127         else {
1128                 if (interval < 65536)
1129                         client->packet.secs = htons(interval);
1130                 else
1131                         client->packet.secs = htons(65535);
1132         }
1133
1134         note("DHCPREQUEST on %s to %s port %d", ifi->name,
1135             inet_ntoa(destination.sin_addr), ntohs(destination.sin_port));
1136
1137         send_packet(from, &destination, NULL);
1138
1139         set_timeout_interval(client->interval, send_request);
1140 }
1141
1142 void
1143 send_decline(void)
1144 {
1145         note("DHCPDECLINE on %s to %s port %d", ifi->name,
1146             inet_ntoa(sockaddr_broadcast.sin_addr),
1147             ntohs(sockaddr_broadcast.sin_port));
1148
1149         send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1150 }
1151
1152 void
1153 make_discover(struct client_lease *lease)
1154 {
1155         unsigned char discover = DHCPDISCOVER;
1156         struct option_data options[256];
1157         int i;
1158
1159         memset(options, 0, sizeof(options));
1160         memset(&client->packet, 0, sizeof(client->packet));
1161
1162         /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */
1163         i = DHO_DHCP_MESSAGE_TYPE;
1164         options[i].data = &discover;
1165         options[i].len = sizeof(discover);
1166
1167         /* Request the options we want */
1168         i  = DHO_DHCP_PARAMETER_REQUEST_LIST;
1169         options[i].data = config->requested_options;
1170         options[i].len = config->requested_option_count;
1171
1172         /* If we had an address, try to get it again. */
1173         if (lease) {
1174                 client->requested_address = lease->address;
1175                 i = DHO_DHCP_REQUESTED_ADDRESS;
1176                 options[i].data = lease->address.iabuf;
1177                 options[i].len = lease->address.len;
1178         } else
1179                 client->requested_address.len = 0;
1180
1181         /* Send any options requested in the config file. */
1182         for (i = 0; i < 256; i++)
1183                 if (!options[i].data &&
1184                     config->send_options[i].data) {
1185                         options[i].data = config->send_options[i].data;
1186                         options[i].len = config->send_options[i].len;
1187                 }
1188
1189         /* Set up the option buffer to fit in a minimal UDP packet. */
1190         i = cons_options(options);
1191         if (i == -1 || client->packet.options[i] != DHO_END)
1192                 error("options do not fit in DHCPDISCOVER packet.");
1193         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1194         if (client->packet_length < BOOTP_MIN_LEN)
1195                 client->packet_length = BOOTP_MIN_LEN;
1196
1197         client->packet.op = BOOTREQUEST;
1198         client->packet.htype = ifi->hw_address.htype;
1199         client->packet.hlen = ifi->hw_address.hlen;
1200         client->packet.hops = 0;
1201         client->packet.xid = arc4random();
1202         client->packet.secs = 0; /* filled in by send_discover. */
1203         client->packet.flags = 0;
1204
1205         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1206         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1207         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1208         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1209         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1210             ifi->hw_address.hlen);
1211 }
1212
1213 void
1214 make_request(struct client_lease * lease)
1215 {
1216         unsigned char request = DHCPREQUEST;
1217         struct option_data options[256];
1218         int i;
1219
1220         memset(options, 0, sizeof(options));
1221         memset(&client->packet, 0, sizeof(client->packet));
1222
1223         /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
1224         i = DHO_DHCP_MESSAGE_TYPE;
1225         options[i].data = &request;
1226         options[i].len = sizeof(request);
1227
1228         /* Request the options we want */
1229         i = DHO_DHCP_PARAMETER_REQUEST_LIST;
1230         options[i].data = config->requested_options;
1231         options[i].len = config->requested_option_count;
1232
1233         /* If we are requesting an address that hasn't yet been assigned
1234            to us, use the DHCP Requested Address option. */
1235         if (client->state == S_REQUESTING) {
1236                 /* Send back the server identifier... */
1237                 i = DHO_DHCP_SERVER_IDENTIFIER;
1238                 options[i].data = lease->options[i].data;
1239                 options[i].len = lease->options[i].len;
1240         }
1241         if (client->state == S_REQUESTING ||
1242             client->state == S_REBOOTING) {
1243                 client->requested_address = lease->address;
1244                 i = DHO_DHCP_REQUESTED_ADDRESS;
1245                 options[i].data = lease->address.iabuf;
1246                 options[i].len = lease->address.len;
1247         } else
1248                 client->requested_address.len = 0;
1249
1250         /* Send any options requested in the config file. */
1251         for (i = 0; i < 256; i++)
1252                 if (!options[i].data && config->send_options[i].data) {
1253                         options[i].data = config->send_options[i].data;
1254                         options[i].len = config->send_options[i].len;
1255                 }
1256
1257         /* Set up the option buffer to fit in a minimal UDP packet. */
1258         i = cons_options(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(options);
1326         if (i == -1 || client->packet.options[i] != DHO_END)
1327                 error("options do not fit in DHCPDECLINE packet.");
1328         client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1329         if (client->packet_length < BOOTP_MIN_LEN)
1330                 client->packet_length = BOOTP_MIN_LEN;
1331
1332         client->packet.op = BOOTREQUEST;
1333         client->packet.htype = ifi->hw_address.htype;
1334         client->packet.hlen = ifi->hw_address.hlen;
1335         client->packet.hops = 0;
1336         client->packet.xid = client->xid;
1337         client->packet.secs = 0; /* Filled in by send_request. */
1338         client->packet.flags = 0;
1339
1340         /* ciaddr must always be zero. */
1341         memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1342         memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1343         memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1344         memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1345         memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1346             ifi->hw_address.hlen);
1347 }
1348
1349 void
1350 free_client_lease(struct client_lease *lease)
1351 {
1352         int i;
1353
1354         if (lease->server_name)
1355                 free(lease->server_name);
1356         if (lease->filename)
1357                 free(lease->filename);
1358         for (i = 0; i < 256; i++) {
1359                 if (lease->options[i].len)
1360                         free(lease->options[i].data);
1361         }
1362         free(lease);
1363 }
1364
1365 void
1366 rewrite_client_leases(void)
1367 {
1368         struct client_lease *lp;
1369
1370         if (!leaseFile) /* XXX */
1371                 error("lease file not open");
1372
1373         fflush(leaseFile);
1374         rewind(leaseFile);
1375
1376         for (lp = client->leases; lp; lp = lp->next) {
1377                 if (client->active && addr_eq(lp->address,
1378                         client->active->address))
1379                         continue;
1380                 write_client_lease(lp);
1381         }
1382
1383         if (client->active)
1384                 write_client_lease(client->active);
1385
1386         fflush(leaseFile);
1387         ftruncate(fileno(leaseFile), ftello(leaseFile));
1388         fsync(fileno(leaseFile));
1389 }
1390
1391 void
1392 write_client_lease(struct client_lease *lease)
1393 {
1394         struct tm *t;
1395         int i;
1396
1397         /* If the lease came from the config file, we don't need to stash
1398            a copy in the lease database. */
1399         if (lease->is_static)
1400                 return;
1401
1402         if (!leaseFile) /* XXX */
1403                 error("lease file not open");
1404
1405         fprintf(leaseFile, "lease {\n");
1406         if (lease->is_bootp)
1407                 fprintf(leaseFile, "  bootp;\n");
1408         fprintf(leaseFile, "  interface \"%s\";\n", ifi->name);
1409         fprintf(leaseFile, "  fixed-address %s;\n", piaddr(lease->address));
1410         if (lease->filename)
1411                 fprintf(leaseFile, "  filename \"%s\";\n", lease->filename);
1412         if (lease->server_name)
1413                 fprintf(leaseFile, "  server-name \"%s\";\n",
1414                     lease->server_name);
1415         for (i = 0; i < 256; i++)
1416                 if (lease->options[i].len)
1417                         fprintf(leaseFile, "  option %s %s;\n",
1418                             dhcp_options[i].name,
1419                             pretty_print_option(i, lease->options[i].data,
1420                             lease->options[i].len, 1, 1));
1421
1422         t = gmtime(&lease->renewal);
1423         fprintf(leaseFile, "  renew %d %d/%d/%d %02d:%02d:%02d;\n",
1424             t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1425             t->tm_hour, t->tm_min, t->tm_sec);
1426         t = gmtime(&lease->rebind);
1427         fprintf(leaseFile, "  rebind %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->expiry);
1431         fprintf(leaseFile, "  expire %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         fprintf(leaseFile, "}\n");
1435         fflush(leaseFile);
1436 }
1437
1438 void
1439 script_init(char *reason)
1440 {
1441         size_t           len;
1442         struct imsg_hdr  hdr;
1443         struct buf      *buf;
1444
1445         hdr.code = IMSG_SCRIPT_INIT;
1446         hdr.len = sizeof(struct imsg_hdr) + sizeof(size_t) + strlen(reason);
1447         buf = buf_open(hdr.len);
1448
1449         buf_add(buf, &hdr, sizeof(hdr));
1450         len = strlen(reason);
1451         buf_add(buf, &len, sizeof(len));
1452         buf_add(buf, reason, len);
1453
1454         buf_close(privfd, buf);
1455 }
1456
1457 void
1458 priv_script_init(char *reason)
1459 {
1460         client->scriptEnvsize = 100;
1461         if (client->scriptEnv == NULL)
1462                 client->scriptEnv =
1463                     calloc(client->scriptEnvsize, sizeof(char *));
1464         if (client->scriptEnv == NULL)
1465                 error("script_init: no memory for environment");
1466
1467         client->scriptEnv[0] = strdup(CLIENT_PATH);
1468         if (client->scriptEnv[0] == NULL)
1469                 error("script_init: no memory for environment");
1470
1471         client->scriptEnv[1] = NULL;
1472
1473         script_set_env("", "interface", ifi->name);
1474
1475         script_set_env("", "reason", reason);
1476 }
1477
1478 void
1479 priv_script_write_params(char *prefix, struct client_lease *lease)
1480 {
1481         u_int8_t dbuf[1500];
1482         int i, len = 0;
1483         char tbuf[128];
1484
1485         script_set_env(prefix, "ip_address", piaddr(lease->address));
1486
1487         if (lease->options[DHO_SUBNET_MASK].len &&
1488             (lease->options[DHO_SUBNET_MASK].len <
1489             sizeof(lease->address.iabuf))) {
1490                 struct iaddr netmask, subnet, broadcast;
1491
1492                 memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data,
1493                     lease->options[DHO_SUBNET_MASK].len);
1494                 netmask.len = lease->options[DHO_SUBNET_MASK].len;
1495
1496                 subnet = subnet_number(lease->address, netmask);
1497                 if (subnet.len) {
1498                         script_set_env(prefix, "network_number",
1499                             piaddr(subnet));
1500                         if (!lease->options[DHO_BROADCAST_ADDRESS].len) {
1501                                 broadcast = broadcast_addr(subnet, netmask);
1502                                 if (broadcast.len)
1503                                         script_set_env(prefix,
1504                                             "broadcast_address",
1505                                             piaddr(broadcast));
1506                         }
1507                 }
1508         }
1509
1510         if (lease->filename)
1511                 script_set_env(prefix, "filename", lease->filename);
1512         if (lease->server_name)
1513                 script_set_env(prefix, "server_name",
1514                     lease->server_name);
1515         for (i = 0; i < 256; i++) {
1516                 u_int8_t *dp = NULL;
1517
1518                 if (config->defaults[i].len) {
1519                         if (lease->options[i].len) {
1520                                 switch (config->default_actions[i]) {
1521                                 case ACTION_IGNORE:
1522                                         /* handled below */
1523                                         break;
1524                                 case ACTION_DEFAULT:
1525                                         dp = lease->options[i].data;
1526                                         len = lease->options[i].len;
1527                                         break;
1528                                 case ACTION_SUPERSEDE:
1529 supersede:
1530                                         dp = config->defaults[i].data;
1531                                         len = config->defaults[i].len;
1532                                         break;
1533                                 case ACTION_PREPEND:
1534                                         len = config->defaults[i].len +
1535                                             lease->options[i].len;
1536                                         if (len >= sizeof(dbuf)) {
1537                                                 warning("no space to %s %s",
1538                                                     "prepend option",
1539                                                     dhcp_options[i].name);
1540                                                 goto supersede;
1541                                         }
1542                                         dp = dbuf;
1543                                         memcpy(dp,
1544                                             config->defaults[i].data,
1545                                             config->defaults[i].len);
1546                                         memcpy(dp +
1547                                             config->defaults[i].len,
1548                                             lease->options[i].data,
1549                                             lease->options[i].len);
1550                                         dp[len] = '\0';
1551                                         break;
1552                                 case ACTION_APPEND:
1553                                         len = config->defaults[i].len +
1554                                             lease->options[i].len;
1555                                         if (len >= sizeof(dbuf)) {
1556                                                 warning("no space to %s %s",
1557                                                     "append option",
1558                                                     dhcp_options[i].name);
1559                                                 goto supersede;
1560                                         }
1561                                         dp = dbuf;
1562                                         memcpy(dp, lease->options[i].data,
1563                                             lease->options[i].len);
1564                                         memcpy(dp + lease->options[i].len,
1565                                             config->defaults[i].data,
1566                                             config->defaults[i].len);
1567                                         dp[len] = '\0';
1568                                 }
1569                         } else {
1570                                 dp = config->defaults[i].data;
1571                                 len = config->defaults[i].len;
1572                         }
1573                 } else if (lease->options[i].len) {
1574                         len = lease->options[i].len;
1575                         dp = lease->options[i].data;
1576                 } else {
1577                         len = 0;
1578                 }
1579                 if (len && config->default_actions[i] == ACTION_IGNORE) {
1580                         len = 0;
1581                 }
1582                 if (len) {
1583                         char name[256];
1584
1585                         if (dhcp_option_ev_name(name, sizeof(name),
1586                             &dhcp_options[i]))
1587                                 script_set_env(prefix, name,
1588                                     pretty_print_option(i, dp, len, 0, 0));
1589                 }
1590         }
1591         snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry);
1592         script_set_env(prefix, "expiry", tbuf);
1593 }
1594
1595 void
1596 script_write_params(char *prefix, struct client_lease *lease)
1597 {
1598         size_t           fn_len = 0, sn_len = 0, pr_len = 0;
1599         struct imsg_hdr  hdr;
1600         struct buf      *buf;
1601         int              i;
1602
1603         if (lease->filename != NULL)
1604                 fn_len = strlen(lease->filename);
1605         if (lease->server_name != NULL)
1606                 sn_len = strlen(lease->server_name);
1607         if (prefix != NULL)
1608                 pr_len = strlen(prefix);
1609
1610         hdr.code = IMSG_SCRIPT_WRITE_PARAMS;
1611         hdr.len = sizeof(hdr) + sizeof(struct client_lease) +
1612             sizeof(size_t) + fn_len + sizeof(size_t) + sn_len +
1613             sizeof(size_t) + pr_len;
1614
1615         for (i = 0; i < 256; i++)
1616                 hdr.len += sizeof(int) + lease->options[i].len;
1617
1618         scripttime = time(NULL);
1619
1620         buf = buf_open(hdr.len);
1621
1622         buf_add(buf, &hdr, sizeof(hdr));
1623         buf_add(buf, lease, sizeof(struct client_lease));
1624         buf_add(buf, &fn_len, sizeof(fn_len));
1625         buf_add(buf, lease->filename, fn_len);
1626         buf_add(buf, &sn_len, sizeof(sn_len));
1627         buf_add(buf, lease->server_name, sn_len);
1628         buf_add(buf, &pr_len, sizeof(pr_len));
1629         buf_add(buf, prefix, pr_len);
1630
1631         for (i = 0; i < 256; i++) {
1632                 buf_add(buf, &lease->options[i].len,
1633                     sizeof(lease->options[i].len));
1634                 buf_add(buf, lease->options[i].data,
1635                     lease->options[i].len);
1636         }
1637
1638         buf_close(privfd, buf);
1639 }
1640
1641 int
1642 script_go(void)
1643 {
1644         struct imsg_hdr  hdr;
1645         struct buf      *buf;
1646         int              ret;
1647
1648         scripttime = time(NULL);
1649
1650         hdr.code = IMSG_SCRIPT_GO;
1651         hdr.len = sizeof(struct imsg_hdr);
1652
1653         buf = buf_open(hdr.len);
1654
1655         buf_add(buf, &hdr, sizeof(hdr));
1656         buf_close(privfd, buf);
1657
1658         bzero(&hdr, sizeof(hdr));
1659         buf_read(privfd, &hdr, sizeof(hdr));
1660         if (hdr.code != IMSG_SCRIPT_GO_RET)
1661                 error("unexpected msg type %u", hdr.code);
1662         if (hdr.len != sizeof(hdr) + sizeof(int))
1663                 error("received corrupted message");
1664         buf_read(privfd, &ret, sizeof(ret));
1665
1666         return (ret);
1667 }
1668
1669 int
1670 priv_script_go(void)
1671 {
1672         char *scriptName, *argv[2], **envp;
1673         int pid, wpid, wstatus;
1674
1675         scripttime = time(NULL);
1676
1677         scriptName = config->script_name;
1678         envp = client->scriptEnv;
1679
1680         argv[0] = scriptName;
1681         argv[1] = NULL;
1682
1683         pid = fork();
1684         if (pid < 0) {
1685                 error("fork: %m");
1686                 wstatus = 0;
1687         } else if (pid) {
1688                 do {
1689                         wpid = wait(&wstatus);
1690                 } while (wpid != pid && wpid > 0);
1691                 if (wpid < 0) {
1692                         error("wait: %m");
1693                         wstatus = 0;
1694                 }
1695         } else {
1696                 execve(scriptName, argv, envp);
1697                 error("execve (%s, ...): %m", scriptName);
1698         }
1699
1700         script_flush_env();
1701
1702         return (WEXITSTATUS(wstatus));
1703 }
1704
1705 void
1706 script_set_env(const char *prefix, const char *name, const char *value)
1707 {
1708         int i, j, namelen;
1709
1710         namelen = strlen(name);
1711
1712         for (i = 0; client->scriptEnv[i]; i++)
1713                 if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
1714                     client->scriptEnv[i][namelen] == '=')
1715                         break;
1716
1717         if (client->scriptEnv[i])
1718                 /* Reuse the slot. */
1719                 free(client->scriptEnv[i]);
1720         else {
1721                 /* New variable.  Expand if necessary. */
1722                 if (i >= client->scriptEnvsize - 1) {
1723                         char **newscriptEnv;
1724                         int newscriptEnvsize = client->scriptEnvsize + 50;
1725
1726                         newscriptEnv = realloc(client->scriptEnv,
1727                             newscriptEnvsize);
1728                         if (newscriptEnv == NULL) {
1729                                 free(client->scriptEnv);
1730                                 client->scriptEnv = NULL;
1731                                 client->scriptEnvsize = 0;
1732                                 error("script_set_env: no memory for variable");
1733                         }
1734                         client->scriptEnv = newscriptEnv;
1735                         client->scriptEnvsize = newscriptEnvsize;
1736                 }
1737                 /* need to set the NULL pointer at end of array beyond
1738                    the new slot. */
1739                 client->scriptEnv[i + 1] = NULL;
1740         }
1741         /* Allocate space and format the variable in the appropriate slot. */
1742         client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
1743             strlen(value) + 1);
1744         if (client->scriptEnv[i] == NULL)
1745                 error("script_set_env: no memory for variable assignment");
1746
1747         /* No `` or $() command substitution allowed in environment values! */
1748         for (j = 0; j < strlen(value); j++)
1749                 switch (value[j]) {
1750                 case '`':
1751                 case '$':
1752                         error("illegal character (%c) in value '%s'", value[j],
1753                             value);
1754                         /* not reached */
1755                 }
1756         snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1757             1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
1758 }
1759
1760 void
1761 script_flush_env(void)
1762 {
1763         int i;
1764
1765         for (i = 0; client->scriptEnv[i]; i++) {
1766                 free(client->scriptEnv[i]);
1767                 client->scriptEnv[i] = NULL;
1768         }
1769         client->scriptEnvsize = 0;
1770 }
1771
1772 int
1773 dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option)
1774 {
1775         size_t i;
1776
1777         for (i = 0; option->name[i]; i++) {
1778                 if (i + 1 == buflen)
1779                         return 0;
1780                 if (option->name[i] == '-')
1781                         buf[i] = '_';
1782                 else
1783                         buf[i] = option->name[i];
1784         }
1785
1786         buf[i] = 0;
1787         return 1;
1788 }
1789
1790 void
1791 go_daemon(void)
1792 {
1793         static int state = 0;
1794
1795         if (no_daemon || state)
1796                 return;
1797
1798         state = 1;
1799
1800         /* Stop logging to stderr... */
1801         log_perror = 0;
1802
1803         if (daemon(1, 0) == -1)
1804                 error("daemon");
1805
1806         /* we are chrooted, daemon(3) fails to open /dev/null */
1807         if (nullfd != -1) {
1808                 dup2(nullfd, STDIN_FILENO);
1809                 dup2(nullfd, STDOUT_FILENO);
1810                 dup2(nullfd, STDERR_FILENO);
1811                 close(nullfd);
1812                 nullfd = -1;
1813         }
1814 }
1815
1816 int
1817 check_option(struct client_lease *l, int option)
1818 {
1819         char *opbuf;
1820         char *sbuf;
1821
1822         /* we use this, since this is what gets passed to dhclient-script */
1823
1824         opbuf = pretty_print_option(option, l->options[option].data,
1825             l->options[option].len, 0, 0);
1826
1827         sbuf = option_as_string(option, l->options[option].data,
1828             l->options[option].len);
1829
1830         switch (option) {
1831         case DHO_SUBNET_MASK:
1832         case DHO_SWAP_SERVER:
1833         case DHO_BROADCAST_ADDRESS:
1834         case DHO_DHCP_SERVER_IDENTIFIER:
1835         case DHO_ROUTER_SOLICITATION_ADDRESS:
1836         case DHO_DHCP_REQUESTED_ADDRESS:
1837                 if (ipv4addrs(opbuf) == 0) {
1838                         warning("Invalid IP address in option %s: %s",
1839                             dhcp_options[option].name, opbuf);
1840                         return (0);
1841                 }
1842                 if (l->options[option].len != 4) { /* RFC 2132 */
1843                         warning("warning: Only 1 IP address allowed in "
1844                             "%s option; length %d, must be 4",
1845                             dhcp_options[option].name,
1846                             l->options[option].len);
1847                         l->options[option].len = 4;
1848                 }
1849                 return (1);
1850         case DHO_TIME_SERVERS:
1851         case DHO_NAME_SERVERS:
1852         case DHO_ROUTERS:
1853         case DHO_DOMAIN_NAME_SERVERS:
1854         case DHO_LOG_SERVERS:
1855         case DHO_COOKIE_SERVERS:
1856         case DHO_LPR_SERVERS:
1857         case DHO_IMPRESS_SERVERS:
1858         case DHO_RESOURCE_LOCATION_SERVERS:
1859         case DHO_NIS_SERVERS:
1860         case DHO_NTP_SERVERS:
1861         case DHO_NETBIOS_NAME_SERVERS:
1862         case DHO_NETBIOS_DD_SERVER:
1863         case DHO_FONT_SERVERS:
1864                 if (ipv4addrs(opbuf) == 0) {
1865                         warning("Invalid IP address in option %s: %s",
1866                             dhcp_options[option].name, opbuf);
1867                         return (0);
1868                 }
1869                 return (1);
1870         case DHO_HOST_NAME:
1871         case DHO_DOMAIN_NAME:
1872         case DHO_NIS_DOMAIN:
1873                 if (!res_hnok(sbuf)) {
1874                         warning("Bogus Host Name option %d: %s (%s)", option,
1875                             sbuf, opbuf);
1876                         l->options[option].len = 0;
1877                         free(l->options[option].data);
1878                 }
1879                 return (1);
1880         case DHO_PAD:
1881         case DHO_TIME_OFFSET:
1882         case DHO_BOOT_SIZE:
1883         case DHO_MERIT_DUMP:
1884         case DHO_ROOT_PATH:
1885         case DHO_EXTENSIONS_PATH:
1886         case DHO_IP_FORWARDING:
1887         case DHO_NON_LOCAL_SOURCE_ROUTING:
1888         case DHO_POLICY_FILTER:
1889         case DHO_MAX_DGRAM_REASSEMBLY:
1890         case DHO_DEFAULT_IP_TTL:
1891         case DHO_PATH_MTU_AGING_TIMEOUT:
1892         case DHO_PATH_MTU_PLATEAU_TABLE:
1893         case DHO_INTERFACE_MTU:
1894         case DHO_ALL_SUBNETS_LOCAL:
1895         case DHO_PERFORM_MASK_DISCOVERY:
1896         case DHO_MASK_SUPPLIER:
1897         case DHO_ROUTER_DISCOVERY:
1898         case DHO_STATIC_ROUTES:
1899         case DHO_TRAILER_ENCAPSULATION:
1900         case DHO_ARP_CACHE_TIMEOUT:
1901         case DHO_IEEE802_3_ENCAPSULATION:
1902         case DHO_DEFAULT_TCP_TTL:
1903         case DHO_TCP_KEEPALIVE_INTERVAL:
1904         case DHO_TCP_KEEPALIVE_GARBAGE:
1905         case DHO_VENDOR_ENCAPSULATED_OPTIONS:
1906         case DHO_NETBIOS_NODE_TYPE:
1907         case DHO_NETBIOS_SCOPE:
1908         case DHO_X_DISPLAY_MANAGER:
1909         case DHO_DHCP_LEASE_TIME:
1910         case DHO_DHCP_OPTION_OVERLOAD:
1911         case DHO_DHCP_MESSAGE_TYPE:
1912         case DHO_DHCP_PARAMETER_REQUEST_LIST:
1913         case DHO_DHCP_MESSAGE:
1914         case DHO_DHCP_MAX_MESSAGE_SIZE:
1915         case DHO_DHCP_RENEWAL_TIME:
1916         case DHO_DHCP_REBINDING_TIME:
1917         case DHO_DHCP_CLASS_IDENTIFIER:
1918         case DHO_DHCP_CLIENT_IDENTIFIER:
1919         case DHO_DHCP_USER_CLASS_ID:
1920         case DHO_TFTP_SERVER:
1921         case DHO_END:
1922                 return (1);
1923         default:
1924                 if (!unknown_ok)
1925                         warning("unknown dhcp option value 0x%x", option);
1926                 return (unknown_ok);
1927         }
1928 }
1929
1930 int
1931 res_hnok(const char *name)
1932 {
1933         const char *dn = name;
1934         int pch = '.', ch = *dn++;
1935         int warn = 0;
1936
1937         while (ch != '\0') {
1938                 int nch = *dn++;
1939
1940                 if (ch == '.') {
1941                         ;
1942                 } else if (pch == '.' || nch == '.' || nch == '\0') {
1943                         if (!isalnum(ch))
1944                                 return (0);
1945                 } else if (!isalnum(ch) && ch != '-' && ch != '_')
1946                                 return (0);
1947                 else if (ch == '_' && warn == 0) {
1948                         warning("warning: hostname %s contains an "
1949                             "underscore which violates RFC 952", name);
1950                         warn++;
1951                 }
1952                 pch = ch, ch = nch;
1953         }
1954         return (1);
1955 }
1956
1957 /* Does buf consist only of dotted decimal ipv4 addrs?
1958  * return how many if so,
1959  * otherwise, return 0
1960  */
1961 int
1962 ipv4addrs(char * buf)
1963 {
1964         struct in_addr jnk;
1965         int count = 0;
1966
1967         while (inet_aton(buf, &jnk) == 1){
1968                 count++;
1969                 while (*buf == '.' || isdigit(*buf))
1970                         buf++;
1971                 if (*buf == '\0')
1972                         return (count);
1973                 while (*buf ==  ' ')
1974                         buf++;
1975         }
1976         return (0);
1977 }
1978
1979 char *
1980 option_as_string(unsigned int code, unsigned char *data, int len)
1981 {
1982         static char optbuf[32768]; /* XXX */
1983         char *op = optbuf;
1984         int opleft = sizeof(optbuf);
1985         unsigned char *dp = data;
1986
1987         if (code > 255)
1988                 error("option_as_string: bad code %d", code);
1989
1990         for (; dp < data + len; dp++) {
1991                 if (!isascii(*dp) || !isprint(*dp)) {
1992                         if (dp + 1 != data + len || *dp != 0) {
1993                                 size_t oplen;
1994                                 snprintf(op, opleft, "\\%03o", *dp);
1995                                 oplen = strlen(op);
1996                                 op += oplen;
1997                                 opleft -= oplen;
1998                         }
1999                 } else if (*dp == '"' || *dp == '\'' || *dp == '$' ||
2000                     *dp == '`' || *dp == '\\') {
2001                         *op++ = '\\';
2002                         *op++ = *dp;
2003                         opleft -= 2;
2004                 } else {
2005                         *op++ = *dp;
2006                         opleft--;
2007                 }
2008         }
2009         if (opleft < 1)
2010                 goto toobig;
2011         *op = 0;
2012         return optbuf;
2013 toobig:
2014         warning("dhcp option too large");
2015         return "<error>";
2016 }
2017
2018 int
2019 fork_privchld(int fd, int fd2)
2020 {
2021         struct pollfd pfd[1];
2022         int nfds, pfail = 0;
2023
2024         switch (fork()) {
2025         case -1:
2026                 error("cannot fork");
2027                 break;
2028         case 0:
2029                 break;
2030         default:
2031                 return (0);
2032         }
2033
2034         if (chdir("/") == -1)
2035                 error("chdir(\"/\")");
2036
2037         setproctitle("%s [priv]", ifi->name);
2038
2039         dup2(nullfd, STDIN_FILENO);
2040         dup2(nullfd, STDOUT_FILENO);
2041         dup2(nullfd, STDERR_FILENO);
2042         close(nullfd);
2043         close(fd2);
2044
2045         for (;;) {
2046                 pfd[0].fd = fd;
2047                 pfd[0].events = POLLIN;
2048                 if ((nfds = poll(pfd, 1, INFTIM)) == -1)
2049                         if (errno != EINTR)
2050                                 error("poll error");
2051
2052                 /*
2053                  * Handle temporary errors, but bail if they persist.
2054                  */
2055                 if (nfds == 0 || !(pfd[0].revents & POLLIN)) {
2056                         if (pfail > POLL_FAILURES)
2057                                 error("poll failed > %d times", POLL_FAILURES);
2058                         sleep(pfail * POLL_FAILURE_WAIT);
2059                         pfail++;
2060                         continue;
2061                 }
2062
2063                 dispatch_imsg(fd);
2064         }
2065 }
2066
2067 void
2068 get_ifname(char *ifname, char *arg)
2069 {
2070         struct ifgroupreq ifgr;
2071         struct ifg_req *ifg;
2072         int s, len;
2073
2074         if (!strcmp(arg, "egress")) {
2075                 s = socket(AF_INET, SOCK_DGRAM, 0);
2076                 if (s == -1)
2077                         error("socket error");
2078                 bzero(&ifgr, sizeof(ifgr));
2079                 strlcpy(ifgr.ifgr_name, "egress", sizeof(ifgr.ifgr_name));
2080                 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) {
2081                         if (errno == ENOENT)
2082                                 error("no interface in group egress found");
2083                         error("ioctl SIOCGIFGMEMB: %m");
2084                 }
2085                 len = ifgr.ifgr_len;
2086                 if ((ifgr.ifgr_groups = calloc(1, len)) == NULL)
2087                         error("get_ifname");
2088                 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1)
2089                         error("ioctl SIOCGIFGMEMB: %m");
2090
2091                 arg = NULL;
2092                 for (ifg = ifgr.ifgr_groups;
2093                      ifg && len >= sizeof(struct ifg_req); ifg++) {
2094                         len -= sizeof(struct ifg_req);
2095                         if (arg)
2096                                 error("too many interfaces in group egress");
2097                         arg = ifg->ifgrq_member;
2098                 }
2099
2100                 if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2101                         error("Interface name too long: %m");
2102
2103                 free(ifgr.ifgr_groups);
2104                 close(s);
2105         } else if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2106                 error("Interface name too long");
2107 }