1 /* $OpenBSD: dhclient.c,v 1.118 2008/05/09 05:19:14 reyk Exp $ */ 2 /* $DragonFly: src/sbin/dhclient/dhclient.c,v 1.2 2008/09/10 10:01:18 matthias Exp $ */ 3 4 /* 5 * Copyright 2004 Henning Brauer <henning@openbsd.org> 6 * Copyright (c) 1995, 1996, 1997, 1998, 1999 7 * The Internet Software Consortium. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of The Internet Software Consortium nor the names 19 * of its contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 23 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 24 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 26 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 29 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 30 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 31 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * This software has been written for the Internet Software Consortium 37 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 38 * Enterprises. To learn more about the Internet Software Consortium, 39 * see ``http://www.vix.com/isc''. To learn more about Vixie 40 * Enterprises, see ``http://www.vix.com''. 41 * 42 * This client was substantially modified and enhanced by Elliot Poger 43 * for use on Linux while he was working on the MosquitoNet project at 44 * Stanford. 45 * 46 * The current version owes much to Elliot's Linux enhancements, but 47 * was substantially reorganized and partially rewritten by Ted Lemon 48 * so as to use the same networking framework that the Internet Software 49 * Consortium DHCP server uses. Much system-specific configuration code 50 * was moved into a shell script so that as support for more operating 51 * systems is added, it will not be necessary to port and maintain 52 * system-specific configuration code to these operating systems - instead, 53 * the shell script can invoke the native tools to accomplish the same 54 * purpose. 55 */ 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); 99 100 #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 /* ARGSUSED */ 158 void 159 routehandler(void) 160 { 161 int linkstat; 162 char msg[2048]; 163 struct rt_msghdr *rtm; 164 struct if_msghdr *ifm; 165 struct ifa_msghdr *ifam; 166 struct if_announcemsghdr *ifan; 167 struct client_lease *l; 168 time_t t = time(NULL); 169 struct sockaddr *sa; 170 struct iaddr a; 171 ssize_t n; 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 goto die; 192 193 if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf)) 194 error("king bula sez: len mismatch"); 195 memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len); 196 if (addr_eq(a, defaddr)) 197 break; 198 199 for (l = client->active; l != NULL; l = l->next) 200 if (addr_eq(a, l->address)) 201 break; 202 203 if (l != NULL || (client->alias && 204 addr_eq(a, client->alias->address))) 205 /* new addr is the one we set */ 206 break; 207 208 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 if (scripttime == 0 || t < scripttime + 10) 216 break; 217 goto die; 218 case RTM_IFINFO: 219 ifm = (struct if_msghdr *)rtm; 220 if (ifm->ifm_index != ifi->index) 221 break; 222 if ((rtm->rtm_flags & RTF_UP) == 0) 223 goto die; 224 225 linkstat = 226 LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0; 227 if (linkstat != ifi->linkstat) { 228 debug("link state %s -> %s", 229 ifi->linkstat ? "up" : "down", 230 linkstat ? "up" : "down"); 231 ifi->linkstat = interface_link_status(ifi->name); 232 if (ifi->linkstat) { 233 client->state = S_INIT; 234 state_reboot(); 235 } 236 } 237 break; 238 case RTM_IFANNOUNCE: 239 ifan = (struct if_announcemsghdr *)rtm; 240 if (ifan->ifan_what == IFAN_DEPARTURE && 241 ifan->ifan_index == ifi->index) 242 goto die; 243 break; 244 default: 245 break; 246 } 247 return; 248 249 die: 250 script_init("FAIL", NULL); 251 if (client->alias) 252 script_write_params("alias_", client->alias); 253 script_go(); 254 exit(1); 255 } 256 257 int 258 main(int argc, char *argv[]) 259 { 260 int ch, fd, quiet = 0, i = 0, pipe_fd[2]; 261 struct passwd *pw; 262 263 /* Initially, log errors to stderr as well as to syslogd. */ 264 openlog(getprogname(), LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY); 265 setlogmask(LOG_UPTO(LOG_INFO)); 266 267 while ((ch = getopt(argc, argv, "c:dl:qu")) != -1) 268 switch (ch) { 269 case 'c': 270 path_dhclient_conf = optarg; 271 break; 272 case 'd': 273 no_daemon = 1; 274 break; 275 case 'l': 276 path_dhclient_db = optarg; 277 break; 278 case 'q': 279 quiet = 1; 280 break; 281 case 'u': 282 unknown_ok = 0; 283 break; 284 default: 285 usage(); 286 } 287 288 argc -= optind; 289 argv += optind; 290 291 if (argc != 1) 292 usage(); 293 294 ifi = calloc(1, sizeof(*ifi)); 295 if (ifi == NULL) 296 error("ifi calloc"); 297 client = calloc(1, sizeof(*client)); 298 if (client == NULL) 299 error("client calloc"); 300 config = calloc(1, sizeof(*config)); 301 if (config == NULL) 302 error("config calloc"); 303 304 if (strlcpy(ifi->name, argv[0], IFNAMSIZ) >= IFNAMSIZ) 305 error("Interface name too long"); 306 if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s", 307 _PATH_DHCLIENT_DB, ifi->name) == -1) 308 error("asprintf"); 309 310 if (quiet) 311 log_perror = 0; 312 313 tzset(); 314 time(&cur_time); 315 316 memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast)); 317 sockaddr_broadcast.sin_family = AF_INET; 318 sockaddr_broadcast.sin_port = htons(REMOTE_PORT); 319 sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST; 320 sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast); 321 inaddr_any.s_addr = INADDR_ANY; 322 323 read_client_conf(); 324 325 if (interface_status(ifi->name) == 0) { 326 interface_link_forceup(ifi->name); 327 /* Give it up to 4 seconds of silent grace to find link */ 328 i = -4; 329 } else 330 i = 0; 331 332 while (!(ifi->linkstat = interface_link_status(ifi->name))) { 333 if (i == 0) 334 fprintf(stderr, "%s: no link ...", ifi->name); 335 else if (i > 0) 336 fprintf(stderr, "."); 337 fflush(stderr); 338 if (++i > config->link_timeout) { 339 fprintf(stderr, " sleeping\n"); 340 goto dispatch; 341 } 342 sleep(1); 343 } 344 if (i >= 0) 345 fprintf(stderr, " got link\n"); 346 347 dispatch: 348 if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1) 349 error("cannot open %s: %m", _PATH_DEVNULL); 350 351 if ((pw = getpwnam("_dhcp")) == NULL) { 352 warning("no such user: _dhcp, falling back to \"nobody\""); 353 if ((pw = getpwnam("nobody")) == NULL) 354 error("no such user: nobody"); 355 } 356 357 if (pipe(pipe_fd) == -1) 358 error("pipe"); 359 360 fork_privchld(pipe_fd[0], pipe_fd[1]); 361 362 close(pipe_fd[0]); 363 privfd = pipe_fd[1]; 364 365 if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1) 366 error("can't open and lock %s: %m", path_dhclient_db); 367 read_client_leases(); 368 if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL) 369 error("can't open %s: %m", path_dhclient_db); 370 rewrite_client_leases(); 371 close(fd); 372 373 priv_script_init("PREINIT", NULL); 374 if (client->alias) 375 priv_script_write_params("alias_", client->alias); 376 priv_script_go(); 377 378 if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1) 379 error("socket(PF_ROUTE, SOCK_RAW): %m"); 380 381 /* set up the interface */ 382 discover_interface(); 383 384 if (chroot(_PATH_VAREMPTY) == -1) 385 error("chroot"); 386 if (chdir("/") == -1) 387 error("chdir(\"/\")"); 388 389 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) 390 error("setresgid"); 391 if (setgroups(1, &pw->pw_gid) == -1) 392 error("setgroups"); 393 if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) 394 error("setresuid"); 395 396 endpwent(); 397 398 setproctitle("%s", ifi->name); 399 400 if (ifi->linkstat) { 401 client->state = S_INIT; 402 state_reboot(); 403 } else 404 go_daemon(); 405 406 dispatch(); 407 408 /* not reached */ 409 return (0); 410 } 411 412 void 413 usage(void) 414 { 415 fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n", 416 getprogname()); 417 exit(1); 418 } 419 420 /* 421 * Individual States: 422 * 423 * Each routine is called from the dhclient_state_machine() in one of 424 * these conditions: 425 * -> entering INIT state 426 * -> recvpacket_flag == 0: timeout in this state 427 * -> otherwise: received a packet in this state 428 * 429 * Return conditions as handled by dhclient_state_machine(): 430 * Returns 1, sendpacket_flag = 1: send packet, reset timer. 431 * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone). 432 * Returns 0: finish the nap which was interrupted for no good reason. 433 * 434 * Several per-interface variables are used to keep track of the process: 435 * active_lease: the lease that is being used on the interface 436 * (null pointer if not configured yet). 437 * offered_leases: leases corresponding to DHCPOFFER messages that have 438 * been sent to us by DHCP servers. 439 * acked_leases: leases corresponding to DHCPACK messages that have been 440 * sent to us by DHCP servers. 441 * sendpacket: DHCP packet we're trying to send. 442 * destination: IP address to send sendpacket to 443 * In addition, there are several relevant per-lease variables. 444 * T1_expiry, T2_expiry, lease_expiry: lease milestones 445 * In the active lease, these control the process of renewing the lease; 446 * In leases on the acked_leases list, this simply determines when we 447 * can no longer legitimately use the lease. 448 */ 449 void 450 state_reboot(void) 451 { 452 /* If we don't remember an active lease, go straight to INIT. */ 453 if (!client->active || client->active->is_bootp) { 454 state_init(); 455 return; 456 } 457 458 /* We are in the rebooting state. */ 459 client->state = S_REBOOTING; 460 461 /* make_request doesn't initialize xid because it normally comes 462 from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER, 463 so pick an xid now. */ 464 client->xid = arc4random(); 465 466 /* Make a DHCPREQUEST packet, and set appropriate per-interface 467 flags. */ 468 make_request(client->active); 469 client->destination = iaddr_broadcast; 470 client->first_sending = cur_time; 471 client->interval = config->initial_interval; 472 473 /* Zap the medium list... */ 474 client->medium = NULL; 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 = config->initial_interval; 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 /* Check to see if we got an ARPREPLY for the address 523 in this particular lease. */ 524 if (!picked) { 525 script_init("ARPCHECK", lp->medium); 526 script_write_params("check_", lp); 527 528 /* If the ARPCHECK code detects another 529 machine using the offered address, it exits 530 nonzero. We need to send a DHCPDECLINE and 531 toss the lease. */ 532 if (script_go()) { 533 make_decline(lp); 534 send_decline(); 535 goto freeit; 536 } 537 picked = lp; 538 picked->next = NULL; 539 } else { 540 freeit: 541 free_client_lease(lp); 542 } 543 } 544 client->offered_leases = NULL; 545 546 /* If we just tossed all the leases we were offered, go back 547 to square one. */ 548 if (!picked) { 549 client->state = S_INIT; 550 state_init(); 551 return; 552 } 553 554 /* If it was a BOOTREPLY, we can just take the address right now. */ 555 if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) { 556 client->new = picked; 557 558 /* Make up some lease expiry times 559 XXX these should be configurable. */ 560 client->new->expiry = cur_time + 12000; 561 client->new->renewal += cur_time + 8000; 562 client->new->rebind += cur_time + 10000; 563 564 client->state = S_REQUESTING; 565 566 /* Bind to the address we received. */ 567 bind_lease(); 568 return; 569 } 570 571 /* Go to the REQUESTING state. */ 572 client->destination = iaddr_broadcast; 573 client->state = S_REQUESTING; 574 client->first_sending = cur_time; 575 client->interval = config->initial_interval; 576 577 /* Make a DHCPREQUEST packet from the lease we picked. */ 578 make_request(picked); 579 client->xid = client->packet.xid; 580 581 /* Toss the lease we picked - we'll get it back in a DHCPACK. */ 582 free_client_lease(picked); 583 584 /* Add an immediate timeout to send the first DHCPREQUEST packet. */ 585 send_request(); 586 } 587 588 void 589 dhcpack(struct iaddr client_addr, struct option_data *options) 590 { 591 struct client_lease *lease; 592 593 if (client->xid != client->packet.xid) 594 return; 595 596 if (client->state != S_REBOOTING && 597 client->state != S_REQUESTING && 598 client->state != S_RENEWING && 599 client->state != S_REBINDING) 600 return; 601 602 note("DHCPACK from %s", piaddr(client_addr)); 603 604 lease = packet_to_lease(options); 605 if (!lease) { 606 note("packet_to_lease failed."); 607 return; 608 } 609 610 client->new = lease; 611 612 /* Stop resending DHCPREQUEST. */ 613 cancel_timeout(send_request); 614 615 /* Figure out the lease time. */ 616 if (client->new->options[DHO_DHCP_LEASE_TIME].data) 617 client->new->expiry = 618 getULong(client->new->options[DHO_DHCP_LEASE_TIME].data); 619 else 620 client->new->expiry = DEFAULT_LEASE_TIME; 621 /* A number that looks negative here is really just very large, 622 because the lease expiry offset is unsigned. */ 623 if (client->new->expiry < 0) 624 client->new->expiry = TIME_MAX; 625 /* XXX should be fixed by resetting the client state */ 626 if (client->new->expiry < 60) 627 client->new->expiry = 60; 628 629 /* Take the server-provided renewal time if there is one; 630 otherwise figure it out according to the spec. */ 631 if (client->new->options[DHO_DHCP_RENEWAL_TIME].len) 632 client->new->renewal = 633 getULong(client->new->options[DHO_DHCP_RENEWAL_TIME].data); 634 else 635 client->new->renewal = client->new->expiry / 2; 636 637 /* Same deal with the rebind time. */ 638 if (client->new->options[DHO_DHCP_REBINDING_TIME].len) 639 client->new->rebind = 640 getULong(client->new->options[DHO_DHCP_REBINDING_TIME].data); 641 else 642 client->new->rebind = client->new->renewal + 643 client->new->renewal / 2 + client->new->renewal / 4; 644 645 client->new->expiry += cur_time; 646 /* Lease lengths can never be negative. */ 647 if (client->new->expiry < cur_time) 648 client->new->expiry = TIME_MAX; 649 client->new->renewal += cur_time; 650 if (client->new->renewal < cur_time) 651 client->new->renewal = TIME_MAX; 652 client->new->rebind += cur_time; 653 if (client->new->rebind < cur_time) 654 client->new->rebind = TIME_MAX; 655 656 bind_lease(); 657 } 658 659 void 660 bind_lease(void) 661 { 662 /* Remember the medium. */ 663 client->new->medium = client->medium; 664 665 /* Write out the new lease. */ 666 write_client_lease(client->new, 0); 667 668 /* Run the client script with the new parameters. */ 669 script_init((client->state == S_REQUESTING ? "BOUND" : 670 (client->state == S_RENEWING ? "RENEW" : 671 (client->state == S_REBOOTING ? "REBOOT" : "REBIND"))), 672 client->new->medium); 673 if (client->active && client->state != S_REBOOTING) 674 script_write_params("old_", client->active); 675 script_write_params("new_", client->new); 676 if (client->alias) 677 script_write_params("alias_", client->alias); 678 script_go(); 679 680 /* Replace the old active lease with the new one. */ 681 if (client->active) 682 free_client_lease(client->active); 683 client->active = client->new; 684 client->new = NULL; 685 686 /* Set up a timeout to start the renewal process. */ 687 add_timeout(client->active->renewal, state_bound); 688 689 note("bound to %s -- renewal in %ld seconds.", 690 piaddr(client->active->address), 691 client->active->renewal - cur_time); 692 client->state = S_BOUND; 693 reinitialize_interface(); 694 go_daemon(); 695 } 696 697 /* 698 * state_bound is called when we've successfully bound to a particular 699 * lease, but the renewal time on that lease has expired. We are 700 * expected to unicast a DHCPREQUEST to the server that gave us our 701 * original lease. 702 */ 703 void 704 state_bound(void) 705 { 706 /* T1 has expired. */ 707 make_request(client->active); 708 client->xid = client->packet.xid; 709 710 if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) { 711 memcpy(client->destination.iabuf, 712 client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data, 713 4); 714 client->destination.len = 4; 715 } else 716 client->destination = iaddr_broadcast; 717 718 client->first_sending = cur_time; 719 client->interval = config->initial_interval; 720 client->state = S_RENEWING; 721 722 /* Send the first packet immediately. */ 723 send_request(); 724 } 725 726 void 727 dhcpoffer(struct iaddr client_addr, struct option_data *options) 728 { 729 struct client_lease *lease, *lp; 730 int i; 731 int arp_timeout_needed, stop_selecting; 732 char *name = options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" : 733 "BOOTREPLY"; 734 735 if (client->xid != client->packet.xid) 736 return; 737 738 if (client->state != S_SELECTING) 739 return; 740 741 note("%s from %s", name, piaddr(client_addr)); 742 743 /* If this lease doesn't supply the minimum required parameters, 744 blow it off. */ 745 for (i = 0; config->required_options[i]; i++) { 746 if (!options[config->required_options[i]].len) { 747 note("%s isn't satisfactory.", name); 748 return; 749 } 750 } 751 752 /* If we've already seen this lease, don't record it again. */ 753 for (lease = client->offered_leases; 754 lease; lease = lease->next) { 755 if (lease->address.len == sizeof(client->packet.yiaddr) && 756 !memcmp(lease->address.iabuf, 757 &client->packet.yiaddr, lease->address.len)) { 758 debug("%s already seen.", name); 759 return; 760 } 761 } 762 763 lease = packet_to_lease(options); 764 if (!lease) { 765 note("packet_to_lease failed."); 766 return; 767 } 768 769 /* If this lease was acquired through a BOOTREPLY, record that 770 fact. */ 771 if (!options[DHO_DHCP_MESSAGE_TYPE].len) 772 lease->is_bootp = 1; 773 774 /* Record the medium under which this lease was offered. */ 775 lease->medium = client->medium; 776 777 /* Send out an ARP Request for the offered IP address. */ 778 script_init("ARPSEND", lease->medium); 779 script_write_params("check_", lease); 780 /* If the script can't send an ARP request without waiting, 781 we'll be waiting when we do the ARPCHECK, so don't wait now. */ 782 if (script_go()) 783 arp_timeout_needed = 0; 784 else 785 arp_timeout_needed = 2; 786 787 /* Figure out when we're supposed to stop selecting. */ 788 stop_selecting = client->first_sending + config->select_interval; 789 790 /* If this is the lease we asked for, put it at the head of the 791 list, and don't mess with the arp request timeout. */ 792 if (lease->address.len == client->requested_address.len && 793 !memcmp(lease->address.iabuf, 794 client->requested_address.iabuf, 795 client->requested_address.len)) { 796 lease->next = client->offered_leases; 797 client->offered_leases = lease; 798 } else { 799 /* If we already have an offer, and arping for this 800 offer would take us past the selection timeout, 801 then don't extend the timeout - just hope for the 802 best. */ 803 if (client->offered_leases && 804 (cur_time + arp_timeout_needed) > stop_selecting) 805 arp_timeout_needed = 0; 806 807 /* Put the lease at the end of the list. */ 808 lease->next = NULL; 809 if (!client->offered_leases) 810 client->offered_leases = lease; 811 else { 812 for (lp = client->offered_leases; lp->next; 813 lp = lp->next) 814 ; /* nothing */ 815 lp->next = lease; 816 } 817 } 818 819 /* If we're supposed to stop selecting before we've had time 820 to wait for the ARPREPLY, add some delay to wait for 821 the ARPREPLY. */ 822 if (stop_selecting - cur_time < arp_timeout_needed) 823 stop_selecting = cur_time + arp_timeout_needed; 824 825 /* If the selecting interval has expired, go immediately to 826 state_selecting(). Otherwise, time out into 827 state_selecting at the select interval. */ 828 if (stop_selecting <= 0) 829 state_selecting(); 830 else { 831 add_timeout(stop_selecting, state_selecting); 832 cancel_timeout(send_discover); 833 } 834 } 835 836 /* 837 * Allocate a client_lease structure and initialize it from the 838 * parameters in the specified packet. 839 */ 840 struct client_lease * 841 packet_to_lease(struct option_data *options) 842 { 843 struct client_lease *lease; 844 int i; 845 846 lease = malloc(sizeof(struct client_lease)); 847 848 if (!lease) { 849 warning("dhcpoffer: no memory to record lease."); 850 return (NULL); 851 } 852 853 memset(lease, 0, sizeof(*lease)); 854 855 /* Copy the lease options. */ 856 for (i = 0; i < 256; i++) { 857 if (options[i].len) { 858 lease->options[i] = options[i]; 859 options[i].data = NULL; 860 options[i].len = 0; 861 if (!check_option(lease, i)) { 862 warning("Invalid lease option - ignoring offer"); 863 free_client_lease(lease); 864 return (NULL); 865 } 866 } 867 } 868 869 lease->address.len = sizeof(client->packet.yiaddr); 870 memcpy(lease->address.iabuf, &client->packet.yiaddr, 871 lease->address.len); 872 873 /* If the server name was filled out, copy it. */ 874 if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len || 875 !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) && 876 client->packet.sname[0]) { 877 lease->server_name = malloc(DHCP_SNAME_LEN + 1); 878 if (!lease->server_name) { 879 warning("dhcpoffer: no memory for server name."); 880 free_client_lease(lease); 881 return (NULL); 882 } 883 memcpy(lease->server_name, client->packet.sname, 884 DHCP_SNAME_LEN); 885 lease->server_name[DHCP_SNAME_LEN] = '\0'; 886 if (!res_hnok(lease->server_name)) { 887 warning("Bogus server name %s", lease->server_name); 888 free(lease->server_name); 889 lease->server_name = NULL; 890 } 891 } 892 893 /* Ditto for the filename. */ 894 if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len || 895 !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) && 896 client->packet.file[0]) { 897 /* Don't count on the NUL terminator. */ 898 lease->filename = malloc(DHCP_FILE_LEN + 1); 899 if (!lease->filename) { 900 warning("dhcpoffer: no memory for filename."); 901 free_client_lease(lease); 902 return (NULL); 903 } 904 memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN); 905 lease->filename[DHCP_FILE_LEN] = '\0'; 906 } 907 return lease; 908 } 909 910 void 911 dhcpnak(struct iaddr client_addr, struct option_data *options) 912 { 913 if (client->xid != client->packet.xid) 914 return; 915 916 if (client->state != S_REBOOTING && 917 client->state != S_REQUESTING && 918 client->state != S_RENEWING && 919 client->state != S_REBINDING) 920 return; 921 922 note("DHCPNAK from %s", piaddr(client_addr)); 923 924 if (!client->active) { 925 note("DHCPNAK with no active lease."); 926 return; 927 } 928 929 free_client_lease(client->active); 930 client->active = NULL; 931 932 /* Stop sending DHCPREQUEST packets... */ 933 cancel_timeout(send_request); 934 935 client->state = S_INIT; 936 state_init(); 937 } 938 939 /* 940 * Send out a DHCPDISCOVER packet, and set a timeout to send out another 941 * one after the right interval has expired. If we don't get an offer by 942 * the time we reach the panic interval, call the panic function. 943 */ 944 void 945 send_discover(void) 946 { 947 int interval, increase = 1; 948 949 /* Figure out how long it's been since we started transmitting. */ 950 interval = cur_time - client->first_sending; 951 952 /* If we're past the panic timeout, call the script and tell it 953 we haven't found anything for this interface yet. */ 954 if (interval > config->timeout) { 955 state_panic(); 956 return; 957 } 958 959 /* If we're selecting media, try the whole list before doing 960 the exponential backoff, but if we've already received an 961 offer, stop looping, because we obviously have it right. */ 962 if (!client->offered_leases && config->media) { 963 int fail = 0; 964 again: 965 if (client->medium) { 966 client->medium = client->medium->next; 967 increase = 0; 968 } 969 if (!client->medium) { 970 if (fail) 971 error("No valid media types for %s!", ifi->name); 972 client->medium = config->media; 973 increase = 1; 974 } 975 976 note("Trying medium \"%s\" %d", client->medium->string, 977 increase); 978 script_init("MEDIUM", client->medium); 979 if (script_go()) 980 goto again; 981 } 982 983 /* 984 * If we're supposed to increase the interval, do so. If it's 985 * currently zero (i.e., we haven't sent any packets yet), set 986 * it to initial_interval; otherwise, add to it a random 987 * number between zero and two times itself. On average, this 988 * means that it will double with every transmission. 989 */ 990 if (increase) { 991 if (!client->interval) 992 client->interval = config->initial_interval; 993 else { 994 client->interval += (arc4random() >> 2) % 995 (2 * client->interval); 996 } 997 998 /* Don't backoff past cutoff. */ 999 if (client->interval > config->backoff_cutoff) 1000 client->interval = ((config->backoff_cutoff / 2) 1001 + ((arc4random() >> 2) % 1002 config->backoff_cutoff)); 1003 } else if (!client->interval) 1004 client->interval = config->initial_interval; 1005 1006 /* If the backoff would take us to the panic timeout, just use that 1007 as the interval. */ 1008 if (cur_time + client->interval > 1009 client->first_sending + config->timeout) 1010 client->interval = (client->first_sending + 1011 config->timeout) - cur_time + 1; 1012 1013 /* Record the number of seconds since we started sending. */ 1014 if (interval < 65536) 1015 client->packet.secs = htons(interval); 1016 else 1017 client->packet.secs = htons(65535); 1018 client->secs = client->packet.secs; 1019 1020 note("DHCPDISCOVER on %s to %s port %d interval %ld", 1021 ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr), 1022 ntohs(sockaddr_broadcast.sin_port), client->interval); 1023 1024 /* Send out a packet. */ 1025 send_packet(inaddr_any, &sockaddr_broadcast, NULL); 1026 1027 add_timeout(cur_time + client->interval, send_discover); 1028 } 1029 1030 /* 1031 * state_panic gets called if we haven't received any offers in a preset 1032 * amount of time. When this happens, we try to use existing leases 1033 * that haven't yet expired, and failing that, we call the client script 1034 * and hope it can do something. 1035 */ 1036 void 1037 state_panic(void) 1038 { 1039 struct client_lease *loop = client->active; 1040 struct client_lease *lp; 1041 1042 note("No DHCPOFFERS received."); 1043 1044 /* We may not have an active lease, but we may have some 1045 predefined leases that we can try. */ 1046 if (!client->active && client->leases) 1047 goto activate_next; 1048 1049 /* Run through the list of leases and see if one can be used. */ 1050 while (client->active) { 1051 if (client->active->expiry > cur_time) { 1052 note("Trying recorded lease %s", 1053 piaddr(client->active->address)); 1054 /* Run the client script with the existing 1055 parameters. */ 1056 script_init("TIMEOUT", 1057 client->active->medium); 1058 script_write_params("new_", client->active); 1059 if (client->alias) 1060 script_write_params("alias_", 1061 client->alias); 1062 1063 /* If the old lease is still good and doesn't 1064 yet need renewal, go into BOUND state and 1065 timeout at the renewal time. */ 1066 if (!script_go()) { 1067 if (cur_time < 1068 client->active->renewal) { 1069 client->state = S_BOUND; 1070 note("bound: renewal in %ld seconds.", 1071 client->active->renewal - 1072 cur_time); 1073 add_timeout(client->active->renewal, 1074 state_bound); 1075 } else { 1076 client->state = S_BOUND; 1077 note("bound: immediate renewal."); 1078 state_bound(); 1079 } 1080 reinitialize_interface(); 1081 go_daemon(); 1082 return; 1083 } 1084 } 1085 1086 /* If there are no other leases, give up. */ 1087 if (!client->leases) { 1088 client->leases = client->active; 1089 client->active = NULL; 1090 break; 1091 } 1092 1093 activate_next: 1094 /* Otherwise, put the active lease at the end of the 1095 lease list, and try another lease.. */ 1096 for (lp = client->leases; lp->next; lp = lp->next) 1097 ; 1098 lp->next = client->active; 1099 if (lp->next) 1100 lp->next->next = NULL; 1101 client->active = client->leases; 1102 client->leases = client->leases->next; 1103 1104 /* If we already tried this lease, we've exhausted the 1105 set of leases, so we might as well give up for 1106 now. */ 1107 if (client->active == loop) 1108 break; 1109 else if (!loop) 1110 loop = client->active; 1111 } 1112 1113 /* No leases were available, or what was available didn't work, so 1114 tell the shell script that we failed to allocate an address, 1115 and try again later. */ 1116 note("No working leases in persistent database - sleeping."); 1117 script_init("FAIL", NULL); 1118 if (client->alias) 1119 script_write_params("alias_", client->alias); 1120 script_go(); 1121 client->state = S_INIT; 1122 add_timeout(cur_time + config->retry_interval, state_init); 1123 go_daemon(); 1124 } 1125 1126 void 1127 send_request(void) 1128 { 1129 struct sockaddr_in destination; 1130 struct in_addr from; 1131 int interval; 1132 1133 /* Figure out how long it's been since we started transmitting. */ 1134 interval = cur_time - client->first_sending; 1135 1136 /* If we're in the INIT-REBOOT or REQUESTING state and we're 1137 past the reboot timeout, go to INIT and see if we can 1138 DISCOVER an address... */ 1139 /* XXX In the INIT-REBOOT state, if we don't get an ACK, it 1140 means either that we're on a network with no DHCP server, 1141 or that our server is down. In the latter case, assuming 1142 that there is a backup DHCP server, DHCPDISCOVER will get 1143 us a new address, but we could also have successfully 1144 reused our old address. In the former case, we're hosed 1145 anyway. This is not a win-prone situation. */ 1146 if ((client->state == S_REBOOTING || 1147 client->state == S_REQUESTING) && 1148 interval > config->reboot_timeout) { 1149 cancel: 1150 client->state = S_INIT; 1151 cancel_timeout(send_request); 1152 state_init(); 1153 return; 1154 } 1155 1156 /* If we're in the reboot state, make sure the media is set up 1157 correctly. */ 1158 if (client->state == S_REBOOTING && 1159 !client->medium && 1160 client->active->medium) { 1161 script_init("MEDIUM", client->active->medium); 1162 1163 /* If the medium we chose won't fly, go to INIT state. */ 1164 if (script_go()) 1165 goto cancel; 1166 1167 /* Record the medium. */ 1168 client->medium = client->active->medium; 1169 } 1170 1171 /* If the lease has expired, relinquish the address and go back 1172 to the INIT state. */ 1173 if (client->state != S_REQUESTING && 1174 cur_time > client->active->expiry) { 1175 /* Run the client script with the new parameters. */ 1176 script_init("EXPIRE", NULL); 1177 script_write_params("old_", client->active); 1178 if (client->alias) 1179 script_write_params("alias_", client->alias); 1180 script_go(); 1181 1182 /* Now do a preinit on the interface so that we can 1183 discover a new address. */ 1184 script_init("PREINIT", NULL); 1185 if (client->alias) 1186 script_write_params("alias_", client->alias); 1187 script_go(); 1188 1189 client->state = S_INIT; 1190 state_init(); 1191 return; 1192 } 1193 1194 /* Do the exponential backoff... */ 1195 if (!client->interval) 1196 client->interval = config->initial_interval; 1197 else 1198 client->interval += ((arc4random() >> 2) % 1199 (2 * client->interval)); 1200 1201 /* Don't backoff past cutoff. */ 1202 if (client->interval > config->backoff_cutoff) 1203 client->interval = ((config->backoff_cutoff / 2) + 1204 ((arc4random() >> 2) % client->interval)); 1205 1206 /* If the backoff would take us to the expiry time, just set the 1207 timeout to the expiry time. */ 1208 if (client->state != S_REQUESTING && cur_time + client->interval > 1209 client->active->expiry) 1210 client->interval = client->active->expiry - cur_time + 1; 1211 1212 /* If the lease T2 time has elapsed, or if we're not yet bound, 1213 broadcast the DHCPREQUEST rather than unicasting. */ 1214 memset(&destination, 0, sizeof(destination)); 1215 if (client->state == S_REQUESTING || 1216 client->state == S_REBOOTING || 1217 cur_time > client->active->rebind) 1218 destination.sin_addr.s_addr = INADDR_BROADCAST; 1219 else 1220 memcpy(&destination.sin_addr.s_addr, client->destination.iabuf, 1221 sizeof(destination.sin_addr.s_addr)); 1222 destination.sin_port = htons(REMOTE_PORT); 1223 destination.sin_family = AF_INET; 1224 destination.sin_len = sizeof(destination); 1225 1226 if (client->state != S_REQUESTING) 1227 memcpy(&from, client->active->address.iabuf, sizeof(from)); 1228 else 1229 from.s_addr = INADDR_ANY; 1230 1231 /* Record the number of seconds since we started sending. */ 1232 if (client->state == S_REQUESTING) 1233 client->packet.secs = client->secs; 1234 else { 1235 if (interval < 65536) 1236 client->packet.secs = htons(interval); 1237 else 1238 client->packet.secs = htons(65535); 1239 } 1240 1241 note("DHCPREQUEST on %s to %s port %d", ifi->name, 1242 inet_ntoa(destination.sin_addr), ntohs(destination.sin_port)); 1243 1244 /* Send out a packet. */ 1245 send_packet(from, &destination, NULL); 1246 1247 add_timeout(cur_time + client->interval, send_request); 1248 } 1249 1250 void 1251 send_decline(void) 1252 { 1253 note("DHCPDECLINE on %s to %s port %d", ifi->name, 1254 inet_ntoa(sockaddr_broadcast.sin_addr), 1255 ntohs(sockaddr_broadcast.sin_port)); 1256 1257 /* Send out a packet. */ 1258 send_packet(inaddr_any, &sockaddr_broadcast, NULL); 1259 } 1260 1261 void 1262 make_discover(struct client_lease *lease) 1263 { 1264 unsigned char discover = DHCPDISCOVER; 1265 struct option_data options[256]; 1266 int i; 1267 1268 memset(options, 0, sizeof(options)); 1269 memset(&client->packet, 0, sizeof(client->packet)); 1270 1271 /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */ 1272 i = DHO_DHCP_MESSAGE_TYPE; 1273 options[i].data = &discover; 1274 options[i].len = sizeof(discover); 1275 1276 /* Request the options we want */ 1277 i = DHO_DHCP_PARAMETER_REQUEST_LIST; 1278 options[i].data = config->requested_options; 1279 options[i].len = config->requested_option_count; 1280 1281 /* If we had an address, try to get it again. */ 1282 if (lease) { 1283 client->requested_address = lease->address; 1284 i = DHO_DHCP_REQUESTED_ADDRESS; 1285 options[i].data = lease->address.iabuf; 1286 options[i].len = lease->address.len; 1287 } else 1288 client->requested_address.len = 0; 1289 1290 /* Send any options requested in the config file. */ 1291 for (i = 0; i < 256; i++) 1292 if (!options[i].data && 1293 config->send_options[i].data) { 1294 options[i].data = config->send_options[i].data; 1295 options[i].len = config->send_options[i].len; 1296 } 1297 1298 /* Set up the option buffer to fit in a minimal UDP packet. */ 1299 i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN, 1300 options); 1301 if (i == -1 || client->packet.options[i] != DHO_END) 1302 error("options do not fit in DHCPDISCOVER packet."); 1303 client->packet_length = DHCP_FIXED_NON_UDP+i+1; 1304 if (client->packet_length < BOOTP_MIN_LEN) 1305 client->packet_length = BOOTP_MIN_LEN; 1306 1307 client->packet.op = BOOTREQUEST; 1308 client->packet.htype = ifi->hw_address.htype; 1309 client->packet.hlen = ifi->hw_address.hlen; 1310 client->packet.hops = 0; 1311 client->packet.xid = arc4random(); 1312 client->packet.secs = 0; /* filled in by send_discover. */ 1313 client->packet.flags = 0; 1314 1315 memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr)); 1316 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); 1317 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); 1318 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); 1319 memcpy(client->packet.chaddr, ifi->hw_address.haddr, 1320 ifi->hw_address.hlen); 1321 } 1322 1323 void 1324 make_request(struct client_lease * lease) 1325 { 1326 unsigned char request = DHCPREQUEST; 1327 struct option_data options[256]; 1328 int i; 1329 1330 memset(options, 0, sizeof(options)); 1331 memset(&client->packet, 0, sizeof(client->packet)); 1332 1333 /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */ 1334 i = DHO_DHCP_MESSAGE_TYPE; 1335 options[i].data = &request; 1336 options[i].len = sizeof(request); 1337 1338 /* Request the options we want */ 1339 i = DHO_DHCP_PARAMETER_REQUEST_LIST; 1340 options[i].data = config->requested_options; 1341 options[i].len = config->requested_option_count; 1342 1343 /* If we are requesting an address that hasn't yet been assigned 1344 to us, use the DHCP Requested Address option. */ 1345 if (client->state == S_REQUESTING) { 1346 /* Send back the server identifier... */ 1347 i = DHO_DHCP_SERVER_IDENTIFIER; 1348 options[i].data = lease->options[i].data; 1349 options[i].len = lease->options[i].len; 1350 } 1351 if (client->state == S_REQUESTING || 1352 client->state == S_REBOOTING) { 1353 client->requested_address = lease->address; 1354 i = DHO_DHCP_REQUESTED_ADDRESS; 1355 options[i].data = lease->address.iabuf; 1356 options[i].len = lease->address.len; 1357 } else 1358 client->requested_address.len = 0; 1359 1360 /* Send any options requested in the config file. */ 1361 for (i = 0; i < 256; i++) 1362 if (!options[i].data && config->send_options[i].data) { 1363 options[i].data = config->send_options[i].data; 1364 options[i].len = config->send_options[i].len; 1365 } 1366 1367 /* Set up the option buffer to fit in a minimal UDP packet. */ 1368 i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN, 1369 options); 1370 if (i == -1 || client->packet.options[i] != DHO_END) 1371 error("options do not fit in DHCPREQUEST packet."); 1372 client->packet_length = DHCP_FIXED_NON_UDP+i+1; 1373 if (client->packet_length < BOOTP_MIN_LEN) 1374 client->packet_length = BOOTP_MIN_LEN; 1375 1376 client->packet.op = BOOTREQUEST; 1377 client->packet.htype = ifi->hw_address.htype; 1378 client->packet.hlen = ifi->hw_address.hlen; 1379 client->packet.hops = 0; 1380 client->packet.xid = client->xid; 1381 client->packet.secs = 0; /* Filled in by send_request. */ 1382 client->packet.flags = 0; 1383 1384 /* If we own the address we're requesting, put it in ciaddr; 1385 otherwise set ciaddr to zero. */ 1386 if (client->state == S_BOUND || 1387 client->state == S_RENEWING || 1388 client->state == S_REBINDING) { 1389 memcpy(&client->packet.ciaddr, 1390 lease->address.iabuf, lease->address.len); 1391 } else { 1392 memset(&client->packet.ciaddr, 0, 1393 sizeof(client->packet.ciaddr)); 1394 } 1395 1396 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); 1397 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); 1398 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); 1399 memcpy(client->packet.chaddr, ifi->hw_address.haddr, 1400 ifi->hw_address.hlen); 1401 } 1402 1403 void 1404 make_decline(struct client_lease *lease) 1405 { 1406 struct option_data options[256]; 1407 unsigned char decline = DHCPDECLINE; 1408 int i; 1409 1410 memset(options, 0, sizeof(options)); 1411 memset(&client->packet, 0, sizeof(client->packet)); 1412 1413 /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */ 1414 i = DHO_DHCP_MESSAGE_TYPE; 1415 options[i].data = &decline; 1416 options[i].len = sizeof(decline); 1417 1418 /* Send back the server identifier... */ 1419 i = DHO_DHCP_SERVER_IDENTIFIER; 1420 options[i].data = lease->options[i].data; 1421 options[i].len = lease->options[i].len; 1422 1423 /* Send back the address we're declining. */ 1424 i = DHO_DHCP_REQUESTED_ADDRESS; 1425 options[i].data = lease->address.iabuf; 1426 options[i].len = lease->address.len; 1427 1428 /* Send the uid if the user supplied one. */ 1429 i = DHO_DHCP_CLIENT_IDENTIFIER; 1430 if (config->send_options[i].len) { 1431 options[i].data = config->send_options[i].data; 1432 options[i].len = config->send_options[i].len; 1433 } 1434 1435 /* Set up the option buffer to fit in a minimal UDP packet. */ 1436 i = cons_options(client->packet.options, 576 - DHCP_FIXED_LEN, 1437 options); 1438 if (i == -1 || client->packet.options[i] != DHO_END) 1439 error("options do not fit in DHCPDECLINE packet."); 1440 client->packet_length = DHCP_FIXED_NON_UDP+i+1; 1441 if (client->packet_length < BOOTP_MIN_LEN) 1442 client->packet_length = BOOTP_MIN_LEN; 1443 1444 client->packet.op = BOOTREQUEST; 1445 client->packet.htype = ifi->hw_address.htype; 1446 client->packet.hlen = ifi->hw_address.hlen; 1447 client->packet.hops = 0; 1448 client->packet.xid = client->xid; 1449 client->packet.secs = 0; /* Filled in by send_request. */ 1450 client->packet.flags = 0; 1451 1452 /* ciaddr must always be zero. */ 1453 memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr)); 1454 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr)); 1455 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr)); 1456 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr)); 1457 memcpy(client->packet.chaddr, ifi->hw_address.haddr, 1458 ifi->hw_address.hlen); 1459 } 1460 1461 void 1462 free_client_lease(struct client_lease *lease) 1463 { 1464 int i; 1465 1466 if (lease->server_name) 1467 free(lease->server_name); 1468 if (lease->filename) 1469 free(lease->filename); 1470 for (i = 0; i < 256; i++) { 1471 if (lease->options[i].len) 1472 free(lease->options[i].data); 1473 } 1474 free(lease); 1475 } 1476 1477 void 1478 rewrite_client_leases(void) 1479 { 1480 struct client_lease *lp; 1481 1482 if (!leaseFile) /* XXX */ 1483 error("lease file not open"); 1484 1485 fflush(leaseFile); 1486 rewind(leaseFile); 1487 1488 for (lp = client->leases; lp; lp = lp->next) 1489 write_client_lease(lp, 1); 1490 if (client->active) 1491 write_client_lease(client->active, 1); 1492 1493 fflush(leaseFile); 1494 ftruncate(fileno(leaseFile), ftello(leaseFile)); 1495 fsync(fileno(leaseFile)); 1496 } 1497 1498 void 1499 write_client_lease(struct client_lease *lease, int rewrite) 1500 { 1501 static int leases_written; 1502 struct tm *t; 1503 int i; 1504 1505 if (!rewrite) { 1506 if (leases_written++ > 20) { 1507 rewrite_client_leases(); 1508 leases_written = 0; 1509 } 1510 } 1511 1512 /* If the lease came from the config file, we don't need to stash 1513 a copy in the lease database. */ 1514 if (lease->is_static) 1515 return; 1516 1517 if (!leaseFile) /* XXX */ 1518 error("lease file not open"); 1519 1520 fprintf(leaseFile, "lease {\n"); 1521 if (lease->is_bootp) 1522 fprintf(leaseFile, " bootp;\n"); 1523 fprintf(leaseFile, " interface \"%s\";\n", ifi->name); 1524 fprintf(leaseFile, " fixed-address %s;\n", piaddr(lease->address)); 1525 if (lease->filename) 1526 fprintf(leaseFile, " filename \"%s\";\n", lease->filename); 1527 if (lease->server_name) 1528 fprintf(leaseFile, " server-name \"%s\";\n", 1529 lease->server_name); 1530 if (lease->medium) 1531 fprintf(leaseFile, " medium \"%s\";\n", lease->medium->string); 1532 for (i = 0; i < 256; i++) 1533 if (lease->options[i].len) 1534 fprintf(leaseFile, " option %s %s;\n", 1535 dhcp_options[i].name, 1536 pretty_print_option(i, lease->options[i].data, 1537 lease->options[i].len, 1, 1)); 1538 1539 t = gmtime(&lease->renewal); 1540 fprintf(leaseFile, " renew %d %d/%d/%d %02d:%02d:%02d;\n", 1541 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, 1542 t->tm_hour, t->tm_min, t->tm_sec); 1543 t = gmtime(&lease->rebind); 1544 fprintf(leaseFile, " rebind %d %d/%d/%d %02d:%02d:%02d;\n", 1545 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, 1546 t->tm_hour, t->tm_min, t->tm_sec); 1547 t = gmtime(&lease->expiry); 1548 fprintf(leaseFile, " expire %d %d/%d/%d %02d:%02d:%02d;\n", 1549 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, 1550 t->tm_hour, t->tm_min, t->tm_sec); 1551 fprintf(leaseFile, "}\n"); 1552 fflush(leaseFile); 1553 } 1554 1555 void 1556 script_init(char *reason, struct string_list *medium) 1557 { 1558 size_t len, mediumlen = 0; 1559 struct imsg_hdr hdr; 1560 struct buf *buf; 1561 1562 if (medium != NULL && medium->string != NULL) 1563 mediumlen = strlen(medium->string); 1564 1565 hdr.code = IMSG_SCRIPT_INIT; 1566 hdr.len = sizeof(struct imsg_hdr) + 1567 sizeof(size_t) + mediumlen + 1568 sizeof(size_t) + strlen(reason); 1569 1570 buf = buf_open(hdr.len); 1571 1572 buf_add(buf, &hdr, sizeof(hdr)); 1573 buf_add(buf, &mediumlen, sizeof(mediumlen)); 1574 if (mediumlen > 0) 1575 buf_add(buf, medium->string, mediumlen); 1576 len = strlen(reason); 1577 buf_add(buf, &len, sizeof(len)); 1578 buf_add(buf, reason, len); 1579 1580 buf_close(privfd, buf); 1581 } 1582 1583 void 1584 priv_script_init(char *reason, char *medium) 1585 { 1586 client->scriptEnvsize = 100; 1587 if (client->scriptEnv == NULL) 1588 client->scriptEnv = 1589 calloc(client->scriptEnvsize, sizeof(char *)); 1590 if (client->scriptEnv == NULL) 1591 error("script_init: no memory for environment"); 1592 1593 client->scriptEnv[0] = strdup(CLIENT_PATH); 1594 if (client->scriptEnv[0] == NULL) 1595 error("script_init: no memory for environment"); 1596 1597 client->scriptEnv[1] = NULL; 1598 1599 script_set_env("", "interface", ifi->name); 1600 1601 if (medium) 1602 script_set_env("", "medium", medium); 1603 1604 script_set_env("", "reason", reason); 1605 } 1606 1607 void 1608 priv_script_write_params(char *prefix, struct client_lease *lease) 1609 { 1610 u_int8_t dbuf[1500]; 1611 int i, len = 0; 1612 char tbuf[128]; 1613 1614 script_set_env(prefix, "ip_address", piaddr(lease->address)); 1615 1616 if (lease->options[DHO_SUBNET_MASK].len && 1617 (lease->options[DHO_SUBNET_MASK].len < 1618 sizeof(lease->address.iabuf))) { 1619 struct iaddr netmask, subnet, broadcast; 1620 1621 memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data, 1622 lease->options[DHO_SUBNET_MASK].len); 1623 netmask.len = lease->options[DHO_SUBNET_MASK].len; 1624 1625 subnet = subnet_number(lease->address, netmask); 1626 if (subnet.len) { 1627 script_set_env(prefix, "network_number", 1628 piaddr(subnet)); 1629 if (!lease->options[DHO_BROADCAST_ADDRESS].len) { 1630 broadcast = broadcast_addr(subnet, netmask); 1631 if (broadcast.len) 1632 script_set_env(prefix, 1633 "broadcast_address", 1634 piaddr(broadcast)); 1635 } 1636 } 1637 } 1638 1639 if (lease->filename) 1640 script_set_env(prefix, "filename", lease->filename); 1641 if (lease->server_name) 1642 script_set_env(prefix, "server_name", 1643 lease->server_name); 1644 for (i = 0; i < 256; i++) { 1645 u_int8_t *dp = NULL; 1646 1647 if (config->defaults[i].len) { 1648 if (lease->options[i].len) { 1649 switch (config->default_actions[i]) { 1650 case ACTION_DEFAULT: 1651 dp = lease->options[i].data; 1652 len = lease->options[i].len; 1653 break; 1654 case ACTION_SUPERSEDE: 1655 supersede: 1656 dp = config->defaults[i].data; 1657 len = config->defaults[i].len; 1658 break; 1659 case ACTION_PREPEND: 1660 len = config->defaults[i].len + 1661 lease->options[i].len; 1662 if (len > sizeof(dbuf)) { 1663 warning("no space to %s %s", 1664 "prepend option", 1665 dhcp_options[i].name); 1666 goto supersede; 1667 } 1668 dp = dbuf; 1669 memcpy(dp, 1670 config->defaults[i].data, 1671 config->defaults[i].len); 1672 memcpy(dp + 1673 config->defaults[i].len, 1674 lease->options[i].data, 1675 lease->options[i].len); 1676 dp[len] = '\0'; 1677 break; 1678 case ACTION_APPEND: 1679 len = config->defaults[i].len + 1680 lease->options[i].len; 1681 if (len > sizeof(dbuf)) { 1682 warning("no space to %s %s", 1683 "append option", 1684 dhcp_options[i].name); 1685 goto supersede; 1686 } 1687 dp = dbuf; 1688 memcpy(dp, lease->options[i].data, 1689 lease->options[i].len); 1690 memcpy(dp + lease->options[i].len, 1691 config->defaults[i].data, 1692 config->defaults[i].len); 1693 dp[len] = '\0'; 1694 } 1695 } else { 1696 dp = config->defaults[i].data; 1697 len = config->defaults[i].len; 1698 } 1699 } else if (lease->options[i].len) { 1700 len = lease->options[i].len; 1701 dp = lease->options[i].data; 1702 } else { 1703 len = 0; 1704 } 1705 if (len) { 1706 char name[256]; 1707 1708 if (dhcp_option_ev_name(name, sizeof(name), 1709 &dhcp_options[i])) 1710 script_set_env(prefix, name, 1711 pretty_print_option(i, dp, len, 0, 0)); 1712 } 1713 } 1714 snprintf(tbuf, sizeof(tbuf), "%d", (int)lease->expiry); 1715 script_set_env(prefix, "expiry", tbuf); 1716 } 1717 1718 void 1719 script_write_params(char *prefix, struct client_lease *lease) 1720 { 1721 size_t fn_len = 0, sn_len = 0, pr_len = 0; 1722 struct imsg_hdr hdr; 1723 struct buf *buf; 1724 int i; 1725 1726 if (lease->filename != NULL) 1727 fn_len = strlen(lease->filename); 1728 if (lease->server_name != NULL) 1729 sn_len = strlen(lease->server_name); 1730 if (prefix != NULL) 1731 pr_len = strlen(prefix); 1732 1733 hdr.code = IMSG_SCRIPT_WRITE_PARAMS; 1734 hdr.len = sizeof(hdr) + sizeof(struct client_lease) + 1735 sizeof(size_t) + fn_len + sizeof(size_t) + sn_len + 1736 sizeof(size_t) + pr_len; 1737 1738 for (i = 0; i < 256; i++) 1739 hdr.len += sizeof(int) + lease->options[i].len; 1740 1741 scripttime = time(NULL); 1742 1743 buf = buf_open(hdr.len); 1744 1745 buf_add(buf, &hdr, sizeof(hdr)); 1746 buf_add(buf, lease, sizeof(struct client_lease)); 1747 buf_add(buf, &fn_len, sizeof(fn_len)); 1748 buf_add(buf, lease->filename, fn_len); 1749 buf_add(buf, &sn_len, sizeof(sn_len)); 1750 buf_add(buf, lease->server_name, sn_len); 1751 buf_add(buf, &pr_len, sizeof(pr_len)); 1752 buf_add(buf, prefix, pr_len); 1753 1754 for (i = 0; i < 256; i++) { 1755 buf_add(buf, &lease->options[i].len, 1756 sizeof(lease->options[i].len)); 1757 buf_add(buf, lease->options[i].data, 1758 lease->options[i].len); 1759 } 1760 1761 buf_close(privfd, buf); 1762 } 1763 1764 int 1765 script_go(void) 1766 { 1767 struct imsg_hdr hdr; 1768 struct buf *buf; 1769 int ret; 1770 1771 scripttime = time(NULL); 1772 1773 hdr.code = IMSG_SCRIPT_GO; 1774 hdr.len = sizeof(struct imsg_hdr); 1775 1776 buf = buf_open(hdr.len); 1777 1778 buf_add(buf, &hdr, sizeof(hdr)); 1779 buf_close(privfd, buf); 1780 1781 bzero(&hdr, sizeof(hdr)); 1782 buf_read(privfd, &hdr, sizeof(hdr)); 1783 if (hdr.code != IMSG_SCRIPT_GO_RET) 1784 error("unexpected msg type %u", hdr.code); 1785 if (hdr.len != sizeof(hdr) + sizeof(int)) 1786 error("received corrupted message"); 1787 buf_read(privfd, &ret, sizeof(ret)); 1788 1789 return (ret); 1790 } 1791 1792 int 1793 priv_script_go(void) 1794 { 1795 char *scriptName, *argv[2], **envp; 1796 int pid, wpid, wstatus; 1797 1798 scripttime = time(NULL); 1799 1800 scriptName = config->script_name; 1801 envp = client->scriptEnv; 1802 1803 argv[0] = scriptName; 1804 argv[1] = NULL; 1805 1806 pid = fork(); 1807 if (pid < 0) { 1808 error("fork: %m"); 1809 wstatus = 0; 1810 } else if (pid) { 1811 do { 1812 wpid = wait(&wstatus); 1813 } while (wpid != pid && wpid > 0); 1814 if (wpid < 0) { 1815 error("wait: %m"); 1816 wstatus = 0; 1817 } 1818 } else { 1819 execve(scriptName, argv, envp); 1820 error("execve (%s, ...): %m", scriptName); 1821 } 1822 1823 script_flush_env(); 1824 1825 return (WEXITSTATUS(wstatus)); 1826 } 1827 1828 void 1829 script_set_env(const char *prefix, const char *name, const char *value) 1830 { 1831 int i, j, namelen; 1832 1833 namelen = strlen(name); 1834 1835 for (i = 0; client->scriptEnv[i]; i++) 1836 if (strncmp(client->scriptEnv[i], name, namelen) == 0 && 1837 client->scriptEnv[i][namelen] == '=') 1838 break; 1839 1840 if (client->scriptEnv[i]) 1841 /* Reuse the slot. */ 1842 free(client->scriptEnv[i]); 1843 else { 1844 /* New variable. Expand if necessary. */ 1845 if (i >= client->scriptEnvsize - 1) { 1846 char **newscriptEnv; 1847 int newscriptEnvsize = client->scriptEnvsize + 50; 1848 1849 newscriptEnv = realloc(client->scriptEnv, 1850 newscriptEnvsize); 1851 if (newscriptEnv == NULL) { 1852 free(client->scriptEnv); 1853 client->scriptEnv = NULL; 1854 client->scriptEnvsize = 0; 1855 error("script_set_env: no memory for variable"); 1856 } 1857 client->scriptEnv = newscriptEnv; 1858 client->scriptEnvsize = newscriptEnvsize; 1859 } 1860 /* need to set the NULL pointer at end of array beyond 1861 the new slot. */ 1862 client->scriptEnv[i + 1] = NULL; 1863 } 1864 /* Allocate space and format the variable in the appropriate slot. */ 1865 client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 + 1866 strlen(value) + 1); 1867 if (client->scriptEnv[i] == NULL) 1868 error("script_set_env: no memory for variable assignment"); 1869 1870 /* No `` or $() command substitution allowed in environment values! */ 1871 for (j = 0; j < strlen(value); j++) 1872 switch (value[j]) { 1873 case '`': 1874 case '$': 1875 error("illegal character (%c) in value '%s'", value[j], 1876 value); 1877 /* not reached */ 1878 } 1879 snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) + 1880 1 + strlen(value) + 1, "%s%s=%s", prefix, name, value); 1881 } 1882 1883 void 1884 script_flush_env(void) 1885 { 1886 int i; 1887 1888 for (i = 0; client->scriptEnv[i]; i++) { 1889 free(client->scriptEnv[i]); 1890 client->scriptEnv[i] = NULL; 1891 } 1892 client->scriptEnvsize = 0; 1893 } 1894 1895 int 1896 dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option) 1897 { 1898 size_t i; 1899 1900 for (i = 0; option->name[i]; i++) { 1901 if (i + 1 == buflen) 1902 return 0; 1903 if (option->name[i] == '-') 1904 buf[i] = '_'; 1905 else 1906 buf[i] = option->name[i]; 1907 } 1908 1909 buf[i] = 0; 1910 return 1; 1911 } 1912 1913 void 1914 go_daemon(void) 1915 { 1916 static int state = 0; 1917 1918 if (no_daemon || state) 1919 return; 1920 1921 state = 1; 1922 1923 /* Stop logging to stderr... */ 1924 log_perror = 0; 1925 1926 if (daemon(1, 0) == -1) 1927 error("daemon"); 1928 1929 /* we are chrooted, daemon(3) fails to open /dev/null */ 1930 if (nullfd != -1) { 1931 dup2(nullfd, STDIN_FILENO); 1932 dup2(nullfd, STDOUT_FILENO); 1933 dup2(nullfd, STDERR_FILENO); 1934 close(nullfd); 1935 nullfd = -1; 1936 } 1937 } 1938 1939 int 1940 check_option(struct client_lease *l, int option) 1941 { 1942 char *opbuf; 1943 char *sbuf; 1944 1945 /* we use this, since this is what gets passed to dhclient-script */ 1946 1947 opbuf = pretty_print_option(option, l->options[option].data, 1948 l->options[option].len, 0, 0); 1949 1950 sbuf = option_as_string(option, l->options[option].data, 1951 l->options[option].len); 1952 1953 switch (option) { 1954 case DHO_SUBNET_MASK: 1955 case DHO_TIME_SERVERS: 1956 case DHO_NAME_SERVERS: 1957 case DHO_ROUTERS: 1958 case DHO_DOMAIN_NAME_SERVERS: 1959 case DHO_LOG_SERVERS: 1960 case DHO_COOKIE_SERVERS: 1961 case DHO_LPR_SERVERS: 1962 case DHO_IMPRESS_SERVERS: 1963 case DHO_RESOURCE_LOCATION_SERVERS: 1964 case DHO_SWAP_SERVER: 1965 case DHO_BROADCAST_ADDRESS: 1966 case DHO_NIS_SERVERS: 1967 case DHO_NTP_SERVERS: 1968 case DHO_NETBIOS_NAME_SERVERS: 1969 case DHO_NETBIOS_DD_SERVER: 1970 case DHO_FONT_SERVERS: 1971 case DHO_DHCP_SERVER_IDENTIFIER: 1972 if (!ipv4addrs(opbuf)) { 1973 warning("Invalid IP address in option: %s", opbuf); 1974 return (0); 1975 } 1976 return (1); 1977 case DHO_HOST_NAME: 1978 case DHO_DOMAIN_NAME: 1979 case DHO_NIS_DOMAIN: 1980 if (!res_hnok(sbuf)) { 1981 warning("Bogus Host Name option %d: %s (%s)", option, 1982 sbuf, opbuf); 1983 l->options[option].len = 0; 1984 free(l->options[option].data); 1985 } 1986 return (1); 1987 case DHO_PAD: 1988 case DHO_TIME_OFFSET: 1989 case DHO_BOOT_SIZE: 1990 case DHO_MERIT_DUMP: 1991 case DHO_ROOT_PATH: 1992 case DHO_EXTENSIONS_PATH: 1993 case DHO_IP_FORWARDING: 1994 case DHO_NON_LOCAL_SOURCE_ROUTING: 1995 case DHO_POLICY_FILTER: 1996 case DHO_MAX_DGRAM_REASSEMBLY: 1997 case DHO_DEFAULT_IP_TTL: 1998 case DHO_PATH_MTU_AGING_TIMEOUT: 1999 case DHO_PATH_MTU_PLATEAU_TABLE: 2000 case DHO_INTERFACE_MTU: 2001 case DHO_ALL_SUBNETS_LOCAL: 2002 case DHO_PERFORM_MASK_DISCOVERY: 2003 case DHO_MASK_SUPPLIER: 2004 case DHO_ROUTER_DISCOVERY: 2005 case DHO_ROUTER_SOLICITATION_ADDRESS: 2006 case DHO_STATIC_ROUTES: 2007 case DHO_TRAILER_ENCAPSULATION: 2008 case DHO_ARP_CACHE_TIMEOUT: 2009 case DHO_IEEE802_3_ENCAPSULATION: 2010 case DHO_DEFAULT_TCP_TTL: 2011 case DHO_TCP_KEEPALIVE_INTERVAL: 2012 case DHO_TCP_KEEPALIVE_GARBAGE: 2013 case DHO_VENDOR_ENCAPSULATED_OPTIONS: 2014 case DHO_NETBIOS_NODE_TYPE: 2015 case DHO_NETBIOS_SCOPE: 2016 case DHO_X_DISPLAY_MANAGER: 2017 case DHO_DHCP_REQUESTED_ADDRESS: 2018 case DHO_DHCP_LEASE_TIME: 2019 case DHO_DHCP_OPTION_OVERLOAD: 2020 case DHO_DHCP_MESSAGE_TYPE: 2021 case DHO_DHCP_PARAMETER_REQUEST_LIST: 2022 case DHO_DHCP_MESSAGE: 2023 case DHO_DHCP_MAX_MESSAGE_SIZE: 2024 case DHO_DHCP_RENEWAL_TIME: 2025 case DHO_DHCP_REBINDING_TIME: 2026 case DHO_DHCP_CLASS_IDENTIFIER: 2027 case DHO_DHCP_CLIENT_IDENTIFIER: 2028 case DHO_DHCP_USER_CLASS_ID: 2029 case DHO_END: 2030 return (1); 2031 default: 2032 warning("unknown dhcp option value 0x%x", option); 2033 return (unknown_ok); 2034 } 2035 } 2036 2037 int 2038 res_hnok(const char *name) 2039 { 2040 const char *dn = name; 2041 int pch = '.', ch = *dn++; 2042 int warn = 0; 2043 2044 while (ch != '\0') { 2045 int nch = *dn++; 2046 2047 if (ch == '.') { 2048 ; 2049 } else if (pch == '.' || nch == '.' || nch == '\0') { 2050 if (!isalnum(ch)) 2051 return (0); 2052 } else if (!isalnum(ch) && ch != '-' && ch != '_') 2053 return (0); 2054 else if (ch == '_' && warn == 0) { 2055 warning("warning: hostname %s contains an " 2056 "underscore which violates RFC 952", name); 2057 warn++; 2058 } 2059 pch = ch, ch = nch; 2060 } 2061 return (1); 2062 } 2063 2064 /* Does buf consist only of dotted decimal ipv4 addrs? 2065 * return how many if so, 2066 * otherwise, return 0 2067 */ 2068 int 2069 ipv4addrs(char * buf) 2070 { 2071 struct in_addr jnk; 2072 int count = 0; 2073 2074 while (inet_aton(buf, &jnk) == 1){ 2075 count++; 2076 while (*buf == '.' || isdigit(*buf)) 2077 buf++; 2078 if (*buf == '\0') 2079 return (count); 2080 while (*buf == ' ') 2081 buf++; 2082 } 2083 return (0); 2084 } 2085 2086 char * 2087 option_as_string(unsigned int code, unsigned char *data, int len) 2088 { 2089 static char optbuf[32768]; /* XXX */ 2090 char *op = optbuf; 2091 int opleft = sizeof(optbuf); 2092 unsigned char *dp = data; 2093 2094 if (code > 255) 2095 error("option_as_string: bad code %d", code); 2096 2097 for (; dp < data + len; dp++) { 2098 if (!isascii(*dp) || !isprint(*dp)) { 2099 if (dp + 1 != data + len || *dp != 0) { 2100 size_t oplen; 2101 snprintf(op, opleft, "\\%03o", *dp); 2102 oplen = strlen(op); 2103 op += oplen; 2104 opleft -= oplen; 2105 } 2106 } else if (*dp == '"' || *dp == '\'' || *dp == '$' || 2107 *dp == '`' || *dp == '\\') { 2108 *op++ = '\\'; 2109 *op++ = *dp; 2110 opleft -= 2; 2111 } else { 2112 *op++ = *dp; 2113 opleft--; 2114 } 2115 } 2116 if (opleft < 1) 2117 goto toobig; 2118 *op = 0; 2119 return optbuf; 2120 toobig: 2121 warning("dhcp option too large"); 2122 return "<error>"; 2123 } 2124 2125 int 2126 fork_privchld(int fd, int fd2) 2127 { 2128 struct pollfd pfd[1]; 2129 int nfds, pfail = 0; 2130 2131 switch (fork()) { 2132 case -1: 2133 error("cannot fork"); 2134 break; 2135 case 0: 2136 break; 2137 default: 2138 return (0); 2139 } 2140 2141 if (chdir("/") == -1) 2142 error("chdir(\"/\")"); 2143 2144 setproctitle("%s [priv]", ifi->name); 2145 2146 dup2(nullfd, STDIN_FILENO); 2147 dup2(nullfd, STDOUT_FILENO); 2148 dup2(nullfd, STDERR_FILENO); 2149 close(nullfd); 2150 close(fd2); 2151 2152 for (;;) { 2153 pfd[0].fd = fd; 2154 pfd[0].events = POLLIN; 2155 if ((nfds = poll(pfd, 1, INFTIM)) == -1) 2156 if (errno != EINTR) 2157 error("poll error"); 2158 2159 /* 2160 * Handle temporary errors, but bail if they persist. 2161 */ 2162 if (nfds == 0 || !(pfd[0].revents & POLLIN)) { 2163 if (pfail > POLL_FAILURES) 2164 error("poll failed > %d times", POLL_FAILURES); 2165 sleep(pfail * POLL_FAILURE_WAIT); 2166 pfail++; 2167 continue; 2168 } 2169 2170 dispatch_imsg(fd); 2171 } 2172 } 2173