1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * dhcpcd - DHCP client daemon 4 * Copyright (c) 2006-2023 Roy Marples <roy@marples.name> 5 * All rights reserved 6 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/socket.h> 31 32 #include <arpa/inet.h> 33 #include <net/if.h> 34 #include <net/route.h> 35 #include <netinet/if_ether.h> 36 #include <netinet/in_systm.h> 37 #include <netinet/in.h> 38 #include <netinet/ip.h> 39 #define __FAVOR_BSD /* Nasty glibc hack so we can use BSD semantics for UDP */ 40 #include <netinet/udp.h> 41 #undef __FAVOR_BSD 42 43 #ifdef AF_LINK 44 # include <net/if_dl.h> 45 #endif 46 47 #include <assert.h> 48 #include <ctype.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <inttypes.h> 52 #include <stdbool.h> 53 #include <stddef.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 #include <syslog.h> 59 60 #define ELOOP_QUEUE ELOOP_DHCP 61 #include "config.h" 62 #include "arp.h" 63 #include "bpf.h" 64 #include "common.h" 65 #include "dhcp.h" 66 #include "dhcpcd.h" 67 #include "dhcp-common.h" 68 #include "duid.h" 69 #include "eloop.h" 70 #include "if.h" 71 #include "ipv4.h" 72 #include "ipv4ll.h" 73 #include "logerr.h" 74 #include "privsep.h" 75 #include "sa.h" 76 #include "script.h" 77 78 #define DAD "Duplicate address detected" 79 #define DHCP_MIN_LEASE 20 80 81 #define IPV4A ADDRIPV4 | ARRAY 82 #define IPV4R ADDRIPV4 | REQUEST 83 84 /* We should define a maximum for the NAK exponential backoff */ 85 #define NAKOFF_MAX 60 86 87 #ifndef IPDEFTTL 88 #define IPDEFTTL 64 /* RFC1340 */ 89 #endif 90 91 /* Support older systems with different defines */ 92 #if !defined(IP_RECVPKTINFO) && defined(IP_PKTINFO) 93 #define IP_RECVPKTINFO IP_PKTINFO 94 #endif 95 96 /* Assert the correct structure size for on wire */ 97 __CTASSERT(sizeof(struct ip) == 20); 98 __CTASSERT(sizeof(struct udphdr) == 8); 99 __CTASSERT(sizeof(struct bootp) == 300); 100 101 struct dhcp_op { 102 uint8_t value; 103 const char *name; 104 }; 105 106 static const struct dhcp_op dhcp_ops[] = { 107 { DHCP_DISCOVER, "DISCOVER" }, 108 { DHCP_OFFER, "OFFER" }, 109 { DHCP_REQUEST, "REQUEST" }, 110 { DHCP_DECLINE, "DECLINE" }, 111 { DHCP_ACK, "ACK" }, 112 { DHCP_NAK, "NAK" }, 113 { DHCP_RELEASE, "RELEASE" }, 114 { DHCP_INFORM, "INFORM" }, 115 { DHCP_FORCERENEW, "FORCERENEW"}, 116 { 0, NULL } 117 }; 118 119 static const char * const dhcp_params[] = { 120 "ip_address", 121 "subnet_cidr", 122 "network_number", 123 "filename", 124 "server_name", 125 NULL 126 }; 127 128 static int dhcp_openbpf(struct interface *); 129 static void dhcp_start1(void *); 130 #if defined(ARP) && (!defined(KERNEL_RFC5227) || defined(ARPING)) 131 static void dhcp_arp_found(struct arp_state *, const struct arp_msg *); 132 #endif 133 static void dhcp_handledhcp(struct interface *, struct bootp *, size_t, 134 const struct in_addr *); 135 static void dhcp_handleifudp(void *, unsigned short); 136 static int dhcp_initstate(struct interface *); 137 138 void 139 dhcp_printoptions(const struct dhcpcd_ctx *ctx, 140 const struct dhcp_opt *opts, size_t opts_len) 141 { 142 const char * const *p; 143 size_t i, j; 144 const struct dhcp_opt *opt, *opt2; 145 int cols; 146 147 for (p = dhcp_params; *p; p++) 148 printf(" %s\n", *p); 149 150 for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) { 151 for (j = 0, opt2 = opts; j < opts_len; j++, opt2++) 152 if (opt->option == opt2->option) 153 break; 154 if (j == opts_len) { 155 cols = printf("%03d %s", opt->option, opt->var); 156 dhcp_print_option_encoding(opt, cols); 157 } 158 } 159 for (i = 0, opt = opts; i < opts_len; i++, opt++) { 160 cols = printf("%03d %s", opt->option, opt->var); 161 dhcp_print_option_encoding(opt, cols); 162 } 163 } 164 165 static const uint8_t * 166 get_option(struct dhcpcd_ctx *ctx, 167 const struct bootp *bootp, size_t bootp_len, 168 unsigned int opt, size_t *opt_len) 169 { 170 const uint8_t *p, *e; 171 uint8_t l, o, ol, overl, *bp; 172 const uint8_t *op; 173 size_t bl; 174 175 if (bootp == NULL || bootp_len < DHCP_MIN_LEN) { 176 errno = EINVAL; 177 return NULL; 178 } 179 180 /* Check we have the magic cookie */ 181 if (!IS_DHCP(bootp)) { 182 errno = ENOTSUP; 183 return NULL; 184 } 185 186 p = bootp->vend + 4; /* options after the 4 byte cookie */ 187 e = (const uint8_t *)bootp + bootp_len; 188 ol = o = overl = 0; 189 bp = NULL; 190 op = NULL; 191 bl = 0; 192 while (p < e) { 193 o = *p++; 194 switch (o) { 195 case DHO_PAD: 196 /* No length to read */ 197 continue; 198 case DHO_END: 199 if (overl & 1) { 200 /* bit 1 set means parse boot file */ 201 overl = (uint8_t)(overl & ~1); 202 p = bootp->file; 203 e = p + sizeof(bootp->file); 204 } else if (overl & 2) { 205 /* bit 2 set means parse server name */ 206 overl = (uint8_t)(overl & ~2); 207 p = bootp->sname; 208 e = p + sizeof(bootp->sname); 209 } else 210 goto exit; 211 /* No length to read */ 212 continue; 213 } 214 215 /* Check we can read the length */ 216 if (p == e) { 217 errno = EINVAL; 218 return NULL; 219 } 220 l = *p++; 221 222 /* Check we can read the option data, if present */ 223 if (p + l > e) { 224 errno = EINVAL; 225 return NULL; 226 } 227 228 if (o == DHO_OPTSOVERLOADED) { 229 /* Ensure we only get this option once by setting 230 * the last bit as well as the value. 231 * This is valid because only the first two bits 232 * actually mean anything in RFC2132 Section 9.3 */ 233 if (l == 1 && !overl) 234 overl = 0x80 | p[0]; 235 } 236 237 if (o == opt) { 238 if (op) { 239 /* We must concatonate the options. */ 240 if (bl + l > ctx->opt_buffer_len) { 241 size_t pos; 242 uint8_t *nb; 243 244 if (bp) 245 pos = (size_t) 246 (bp - ctx->opt_buffer); 247 else 248 pos = 0; 249 nb = realloc(ctx->opt_buffer, bl + l); 250 if (nb == NULL) 251 return NULL; 252 ctx->opt_buffer = nb; 253 ctx->opt_buffer_len = bl + l; 254 bp = ctx->opt_buffer + pos; 255 } 256 if (bp == NULL) 257 bp = ctx->opt_buffer; 258 memcpy(bp, op, ol); 259 bp += ol; 260 } 261 ol = l; 262 op = p; 263 bl += ol; 264 } 265 p += l; 266 } 267 268 exit: 269 if (opt_len) 270 *opt_len = bl; 271 if (bp) { 272 memcpy(bp, op, ol); 273 return (const uint8_t *)ctx->opt_buffer; 274 } 275 if (op) 276 return op; 277 errno = ENOENT; 278 return NULL; 279 } 280 281 static int 282 get_option_addr(struct dhcpcd_ctx *ctx, 283 struct in_addr *a, const struct bootp *bootp, size_t bootp_len, 284 uint8_t option) 285 { 286 const uint8_t *p; 287 size_t len; 288 289 p = get_option(ctx, bootp, bootp_len, option, &len); 290 if (!p || len < (ssize_t)sizeof(a->s_addr)) 291 return -1; 292 memcpy(&a->s_addr, p, sizeof(a->s_addr)); 293 return 0; 294 } 295 296 static int 297 get_option_uint32(struct dhcpcd_ctx *ctx, 298 uint32_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option) 299 { 300 const uint8_t *p; 301 size_t len; 302 uint32_t d; 303 304 p = get_option(ctx, bootp, bootp_len, option, &len); 305 if (!p || len < (ssize_t)sizeof(d)) 306 return -1; 307 memcpy(&d, p, sizeof(d)); 308 if (i) 309 *i = ntohl(d); 310 return 0; 311 } 312 313 static int 314 get_option_uint16(struct dhcpcd_ctx *ctx, 315 uint16_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option) 316 { 317 const uint8_t *p; 318 size_t len; 319 uint16_t d; 320 321 p = get_option(ctx, bootp, bootp_len, option, &len); 322 if (!p || len < (ssize_t)sizeof(d)) 323 return -1; 324 memcpy(&d, p, sizeof(d)); 325 if (i) 326 *i = ntohs(d); 327 return 0; 328 } 329 330 static int 331 get_option_uint8(struct dhcpcd_ctx *ctx, 332 uint8_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option) 333 { 334 const uint8_t *p; 335 size_t len; 336 337 p = get_option(ctx, bootp, bootp_len, option, &len); 338 if (!p || len < (ssize_t)sizeof(*p)) 339 return -1; 340 if (i) 341 *i = *(p); 342 return 0; 343 } 344 345 ssize_t 346 print_rfc3442(FILE *fp, const uint8_t *data, size_t data_len) 347 { 348 const uint8_t *p = data, *e; 349 size_t ocets; 350 uint8_t cidr; 351 struct in_addr addr; 352 353 /* Minimum is 5 -first is CIDR and a router length of 4 */ 354 if (data_len < 5) { 355 errno = EINVAL; 356 return -1; 357 } 358 359 e = p + data_len; 360 while (p < e) { 361 if (p != data) { 362 if (fputc(' ', fp) == EOF) 363 return -1; 364 } 365 cidr = *p++; 366 if (cidr > 32) { 367 errno = EINVAL; 368 return -1; 369 } 370 ocets = (size_t)(cidr + 7) / NBBY; 371 if (p + 4 + ocets > e) { 372 errno = ERANGE; 373 return -1; 374 } 375 /* If we have ocets then we have a destination and netmask */ 376 addr.s_addr = 0; 377 if (ocets > 0) { 378 memcpy(&addr.s_addr, p, ocets); 379 p += ocets; 380 } 381 if (fprintf(fp, "%s/%d", inet_ntoa(addr), cidr) == -1) 382 return -1; 383 384 /* Finally, snag the router */ 385 memcpy(&addr.s_addr, p, 4); 386 p += 4; 387 if (fprintf(fp, " %s", inet_ntoa(addr)) == -1) 388 return -1; 389 } 390 391 if (fputc('\0', fp) == EOF) 392 return -1; 393 return 1; 394 } 395 396 static int 397 decode_rfc3442_rt(rb_tree_t *routes, struct interface *ifp, 398 const uint8_t *data, size_t dl) 399 { 400 const uint8_t *p = data; 401 const uint8_t *e; 402 uint8_t cidr; 403 size_t ocets; 404 struct rt *rt = NULL; 405 struct in_addr dest, netmask, gateway; 406 int n; 407 408 /* Minimum is 5 -first is CIDR and a router length of 4 */ 409 if (dl < 5) { 410 errno = EINVAL; 411 return -1; 412 } 413 414 n = 0; 415 e = p + dl; 416 while (p < e) { 417 cidr = *p++; 418 if (cidr > 32) { 419 errno = EINVAL; 420 return -1; 421 } 422 423 ocets = (size_t)(cidr + 7) / NBBY; 424 if (p + 4 + ocets > e) { 425 errno = ERANGE; 426 return -1; 427 } 428 429 if ((rt = rt_new(ifp)) == NULL) 430 return -1; 431 432 /* If we have ocets then we have a destination and netmask */ 433 dest.s_addr = 0; 434 if (ocets > 0) { 435 memcpy(&dest.s_addr, p, ocets); 436 p += ocets; 437 netmask.s_addr = htonl(~0U << (32 - cidr)); 438 } else 439 netmask.s_addr = 0; 440 441 /* Finally, snag the router */ 442 memcpy(&gateway.s_addr, p, 4); 443 p += 4; 444 445 if (netmask.s_addr == INADDR_BROADCAST) 446 rt->rt_flags = RTF_HOST; 447 448 sa_in_init(&rt->rt_dest, &dest); 449 sa_in_init(&rt->rt_netmask, &netmask); 450 sa_in_init(&rt->rt_gateway, &gateway); 451 if (rt_proto_add(routes, rt)) 452 n = 1; 453 } 454 return n; 455 } 456 457 ssize_t 458 print_rfc3361(FILE *fp, const uint8_t *data, size_t dl) 459 { 460 uint8_t enc; 461 char sip[NS_MAXDNAME]; 462 struct in_addr addr; 463 464 if (dl < 2) { 465 errno = EINVAL; 466 return 0; 467 } 468 469 enc = *data++; 470 dl--; 471 switch (enc) { 472 case 0: 473 if (decode_rfc1035(sip, sizeof(sip), data, dl) == -1) 474 return -1; 475 if (efprintf(fp, "%s", sip) == -1) 476 return -1; 477 break; 478 case 1: 479 if (dl % 4 != 0) { 480 errno = EINVAL; 481 break; 482 } 483 addr.s_addr = INADDR_BROADCAST; 484 for (; 485 dl != 0; 486 data += sizeof(addr.s_addr), dl -= sizeof(addr.s_addr)) 487 { 488 memcpy(&addr.s_addr, data, sizeof(addr.s_addr)); 489 if (fprintf(fp, "%s", inet_ntoa(addr)) == -1) 490 return -1; 491 if (dl != sizeof(addr.s_addr)) { 492 if (fputc(' ', fp) == EOF) 493 return -1; 494 } 495 } 496 if (fputc('\0', fp) == EOF) 497 return -1; 498 break; 499 default: 500 errno = EINVAL; 501 return 0; 502 } 503 504 return 1; 505 } 506 507 static char * 508 get_option_string(struct dhcpcd_ctx *ctx, 509 const struct bootp *bootp, size_t bootp_len, uint8_t option) 510 { 511 size_t len; 512 const uint8_t *p; 513 char *s; 514 515 p = get_option(ctx, bootp, bootp_len, option, &len); 516 if (!p || len == 0 || *p == '\0') 517 return NULL; 518 519 s = malloc(sizeof(char) * (len + 1)); 520 if (s) { 521 memcpy(s, p, len); 522 s[len] = '\0'; 523 } 524 return s; 525 } 526 527 /* This calculates the netmask that we should use for static routes. 528 * This IS different from the calculation used to calculate the netmask 529 * for an interface address. */ 530 static uint32_t 531 route_netmask(uint32_t ip_in) 532 { 533 /* used to be unsigned long - check if error */ 534 uint32_t p = ntohl(ip_in); 535 uint32_t t; 536 537 if (IN_CLASSA(p)) 538 t = ~IN_CLASSA_NET; 539 else { 540 if (IN_CLASSB(p)) 541 t = ~IN_CLASSB_NET; 542 else { 543 if (IN_CLASSC(p)) 544 t = ~IN_CLASSC_NET; 545 else 546 t = 0; 547 } 548 } 549 550 while (t & p) 551 t >>= 1; 552 553 return (htonl(~t)); 554 } 555 556 /* We need to obey routing options. 557 * If we have a CSR then we only use that. 558 * Otherwise we add static routes and then routers. */ 559 static int 560 get_option_routes(rb_tree_t *routes, struct interface *ifp, 561 const struct bootp *bootp, size_t bootp_len) 562 { 563 struct if_options *ifo = ifp->options; 564 const uint8_t *p; 565 const uint8_t *e; 566 struct rt *rt = NULL; 567 struct in_addr dest, netmask, gateway; 568 size_t len; 569 const char *csr = ""; 570 int n; 571 572 /* If we have CSR's then we MUST use these only */ 573 if (!has_option_mask(ifo->nomask, DHO_CSR)) 574 p = get_option(ifp->ctx, bootp, bootp_len, DHO_CSR, &len); 575 else 576 p = NULL; 577 /* Check for crappy MS option */ 578 if (!p && !has_option_mask(ifo->nomask, DHO_MSCSR)) { 579 p = get_option(ifp->ctx, bootp, bootp_len, DHO_MSCSR, &len); 580 if (p) 581 csr = "MS "; 582 } 583 if (p && (n = decode_rfc3442_rt(routes, ifp, p, len)) != -1) { 584 const struct dhcp_state *state; 585 586 state = D_CSTATE(ifp); 587 if (!(ifo->options & DHCPCD_CSR_WARNED) && 588 !(state->added & STATE_FAKE)) 589 { 590 logdebugx("%s: using %sClassless Static Routes", 591 ifp->name, csr); 592 ifo->options |= DHCPCD_CSR_WARNED; 593 } 594 return n; 595 } 596 597 n = 0; 598 /* OK, get our static routes first. */ 599 if (!has_option_mask(ifo->nomask, DHO_STATICROUTE)) 600 p = get_option(ifp->ctx, bootp, bootp_len, 601 DHO_STATICROUTE, &len); 602 else 603 p = NULL; 604 /* RFC 2131 Section 5.8 states length MUST be in multiples of 8 */ 605 if (p && len % 8 == 0) { 606 e = p + len; 607 while (p < e) { 608 memcpy(&dest.s_addr, p, sizeof(dest.s_addr)); 609 p += 4; 610 memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr)); 611 p += 4; 612 /* RFC 2131 Section 5.8 states default route is 613 * illegal */ 614 if (gateway.s_addr == INADDR_ANY) 615 continue; 616 if ((rt = rt_new(ifp)) == NULL) 617 return -1; 618 619 /* A on-link host route is normally set by having the 620 * gateway match the destination or assigned address */ 621 if (gateway.s_addr == dest.s_addr || 622 (gateway.s_addr == bootp->yiaddr || 623 gateway.s_addr == bootp->ciaddr)) 624 { 625 gateway.s_addr = INADDR_ANY; 626 netmask.s_addr = INADDR_BROADCAST; 627 } else 628 netmask.s_addr = route_netmask(dest.s_addr); 629 if (netmask.s_addr == INADDR_BROADCAST) 630 rt->rt_flags = RTF_HOST; 631 632 sa_in_init(&rt->rt_dest, &dest); 633 sa_in_init(&rt->rt_netmask, &netmask); 634 sa_in_init(&rt->rt_gateway, &gateway); 635 if (rt_proto_add(routes, rt)) 636 n++; 637 } 638 } 639 640 /* Now grab our routers */ 641 if (!has_option_mask(ifo->nomask, DHO_ROUTER)) 642 p = get_option(ifp->ctx, bootp, bootp_len, DHO_ROUTER, &len); 643 else 644 p = NULL; 645 if (p && len % 4 == 0) { 646 e = p + len; 647 dest.s_addr = INADDR_ANY; 648 netmask.s_addr = INADDR_ANY; 649 while (p < e) { 650 if ((rt = rt_new(ifp)) == NULL) 651 return -1; 652 memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr)); 653 p += 4; 654 sa_in_init(&rt->rt_dest, &dest); 655 sa_in_init(&rt->rt_netmask, &netmask); 656 sa_in_init(&rt->rt_gateway, &gateway); 657 if (rt_proto_add(routes, rt)) 658 n++; 659 } 660 } 661 662 return n; 663 } 664 665 uint16_t 666 dhcp_get_mtu(const struct interface *ifp) 667 { 668 const struct dhcp_state *state; 669 uint16_t mtu; 670 671 if (ifp->options->mtu) 672 return (uint16_t)ifp->options->mtu; 673 mtu = 0; /* bogus gcc warning */ 674 if ((state = D_CSTATE(ifp)) == NULL || 675 has_option_mask(ifp->options->nomask, DHO_MTU) || 676 get_option_uint16(ifp->ctx, &mtu, 677 state->new, state->new_len, DHO_MTU) == -1) 678 return 0; 679 return mtu; 680 } 681 682 /* Grab our routers from the DHCP message and apply any MTU value 683 * the message contains */ 684 int 685 dhcp_get_routes(rb_tree_t *routes, struct interface *ifp) 686 { 687 const struct dhcp_state *state; 688 689 if ((state = D_CSTATE(ifp)) == NULL || !(state->added & STATE_ADDED)) 690 return 0; 691 return get_option_routes(routes, ifp, state->new, state->new_len); 692 } 693 694 /* Assumes DHCP options */ 695 static int 696 dhcp_message_add_addr(struct bootp *bootp, 697 uint8_t type, struct in_addr addr) 698 { 699 uint8_t *p; 700 size_t len; 701 702 p = bootp->vend; 703 while (*p != DHO_END) { 704 p++; 705 p += *p + 1; 706 } 707 708 len = (size_t)(p - bootp->vend); 709 if (len + 6 > sizeof(bootp->vend)) { 710 errno = ENOMEM; 711 return -1; 712 } 713 714 *p++ = type; 715 *p++ = 4; 716 memcpy(p, &addr.s_addr, 4); 717 p += 4; 718 *p = DHO_END; 719 return 0; 720 } 721 722 static ssize_t 723 make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type) 724 { 725 struct bootp *bootp; 726 uint8_t *lp, *p, *e; 727 uint8_t *n_params = NULL; 728 uint32_t ul; 729 uint16_t sz; 730 size_t len, i; 731 const struct dhcp_opt *opt; 732 struct if_options *ifo = ifp->options; 733 const struct dhcp_state *state = D_CSTATE(ifp); 734 const struct dhcp_lease *lease = &state->lease; 735 char hbuf[HOSTNAME_MAX_LEN + 1]; 736 const char *hostname; 737 const struct vivco *vivco; 738 int mtu; 739 #ifdef AUTH 740 uint8_t *auth, auth_len; 741 #endif 742 743 if ((mtu = if_getmtu(ifp)) == -1) 744 logerr("%s: if_getmtu", ifp->name); 745 else if (mtu < MTU_MIN) { 746 if (if_setmtu(ifp, MTU_MIN) == -1) 747 logerr("%s: if_setmtu", ifp->name); 748 mtu = MTU_MIN; 749 } 750 751 if (ifo->options & DHCPCD_BOOTP) 752 bootp = calloc(1, sizeof (*bootp)); 753 else 754 /* Make the maximal message we could send */ 755 bootp = calloc(1, (size_t)(mtu - IP_UDP_SIZE)); 756 757 if (bootp == NULL) 758 return -1; 759 *bootpm = bootp; 760 761 if (state->addr != NULL && 762 (type == DHCP_INFORM || type == DHCP_RELEASE || 763 (type == DHCP_REQUEST && 764 state->addr->mask.s_addr == lease->mask.s_addr && 765 (state->new == NULL || IS_DHCP(state->new)) && 766 !(state->added & (STATE_FAKE | STATE_EXPIRED))))) 767 bootp->ciaddr = state->addr->addr.s_addr; 768 769 bootp->op = BOOTREQUEST; 770 bootp->htype = (uint8_t)ifp->hwtype; 771 if (ifp->hwlen != 0 && ifp->hwlen <= sizeof(bootp->chaddr)) { 772 bootp->hlen = (uint8_t)ifp->hwlen; 773 memcpy(&bootp->chaddr, &ifp->hwaddr, ifp->hwlen); 774 } 775 776 if (ifo->options & DHCPCD_BROADCAST && 777 bootp->ciaddr == 0 && 778 type != DHCP_DECLINE && 779 type != DHCP_RELEASE) 780 bootp->flags = htons(BROADCAST_FLAG); 781 782 if (type != DHCP_DECLINE && type != DHCP_RELEASE) { 783 struct timespec tv; 784 unsigned long long secs; 785 786 clock_gettime(CLOCK_MONOTONIC, &tv); 787 secs = eloop_timespec_diff(&tv, &state->started, NULL); 788 if (secs > UINT16_MAX) 789 bootp->secs = htons((uint16_t)UINT16_MAX); 790 else 791 bootp->secs = htons((uint16_t)secs); 792 } 793 794 bootp->xid = htonl(state->xid); 795 796 if (ifo->options & DHCPCD_BOOTP) 797 return sizeof(*bootp); 798 799 p = bootp->vend; 800 e = (uint8_t *)bootp + (mtu - IP_UDP_SIZE) - 1; /* -1 for DHO_END */ 801 802 ul = htonl(MAGIC_COOKIE); 803 memcpy(p, &ul, sizeof(ul)); 804 p += sizeof(ul); 805 806 #define AREA_LEFT (size_t)(e - p) 807 #define AREA_FIT(s) if ((s) > AREA_LEFT) goto toobig 808 #define AREA_CHECK(s) if ((s) + 2UL > AREA_LEFT) goto toobig 809 #define PUT_ADDR(o, a) do { \ 810 AREA_CHECK(4); \ 811 *p++ = (o); \ 812 *p++ = 4; \ 813 memcpy(p, &(a)->s_addr, 4); \ 814 p += 4; \ 815 } while (0 /* CONSTCOND */) 816 817 /* Options are listed in numerical order as per RFC 7844 Section 3.1 818 * XXX: They should be randomised. */ 819 820 bool putip = false; 821 if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) { 822 if (type == DHCP_DECLINE || 823 (type == DHCP_REQUEST && 824 (state->addr == NULL || 825 state->added & (STATE_FAKE | STATE_EXPIRED) || 826 lease->addr.s_addr != state->addr->addr.s_addr))) 827 { 828 putip = true; 829 PUT_ADDR(DHO_IPADDRESS, &lease->addr); 830 } 831 } 832 833 AREA_CHECK(3); 834 *p++ = DHO_MESSAGETYPE; 835 *p++ = 1; 836 *p++ = type; 837 838 if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) { 839 if (type == DHCP_RELEASE || putip) { 840 if (lease->server.s_addr) 841 PUT_ADDR(DHO_SERVERID, &lease->server); 842 } 843 } 844 845 if (type == DHCP_DECLINE) { 846 len = strlen(DAD); 847 if (len > AREA_LEFT) { 848 *p++ = DHO_MESSAGE; 849 *p++ = (uint8_t)len; 850 memcpy(p, DAD, len); 851 p += len; 852 } 853 } 854 855 #define DHCP_DIR(type) ((type) == DHCP_DISCOVER || (type) == DHCP_INFORM || \ 856 (type) == DHCP_REQUEST) 857 858 if (DHCP_DIR(type)) { 859 /* vendor is already encoded correctly, so just add it */ 860 if (ifo->vendor[0]) { 861 AREA_CHECK(ifo->vendor[0]); 862 *p++ = DHO_VENDOR; 863 memcpy(p, ifo->vendor, (size_t)ifo->vendor[0] + 1); 864 p += ifo->vendor[0] + 1; 865 } 866 } 867 868 if (type == DHCP_DISCOVER && ifo->options & DHCPCD_REQUEST) 869 PUT_ADDR(DHO_IPADDRESS, &ifo->req_addr); 870 871 if (DHCP_DIR(type)) { 872 if (type != DHCP_INFORM) { 873 if (ifo->leasetime != 0) { 874 AREA_CHECK(4); 875 *p++ = DHO_LEASETIME; 876 *p++ = 4; 877 ul = htonl(ifo->leasetime); 878 memcpy(p, &ul, 4); 879 p += 4; 880 } 881 } 882 883 AREA_CHECK(0); 884 *p++ = DHO_PARAMETERREQUESTLIST; 885 n_params = p; 886 *p++ = 0; 887 for (i = 0, opt = ifp->ctx->dhcp_opts; 888 i < ifp->ctx->dhcp_opts_len; 889 i++, opt++) 890 { 891 if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask)) 892 continue; 893 if (type == DHCP_INFORM && 894 (opt->option == DHO_RENEWALTIME || 895 opt->option == DHO_REBINDTIME)) 896 continue; 897 AREA_FIT(1); 898 *p++ = (uint8_t)opt->option; 899 } 900 for (i = 0, opt = ifo->dhcp_override; 901 i < ifo->dhcp_override_len; 902 i++, opt++) 903 { 904 /* Check if added above */ 905 for (lp = n_params + 1; lp < p; lp++) 906 if (*lp == (uint8_t)opt->option) 907 break; 908 if (lp < p) 909 continue; 910 if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask)) 911 continue; 912 if (type == DHCP_INFORM && 913 (opt->option == DHO_RENEWALTIME || 914 opt->option == DHO_REBINDTIME)) 915 continue; 916 AREA_FIT(1); 917 *p++ = (uint8_t)opt->option; 918 } 919 *n_params = (uint8_t)(p - n_params - 1); 920 921 if (mtu != -1 && 922 !(has_option_mask(ifo->nomask, DHO_MAXMESSAGESIZE))) 923 { 924 AREA_CHECK(2); 925 *p++ = DHO_MAXMESSAGESIZE; 926 *p++ = 2; 927 sz = htons((uint16_t)(mtu - IP_UDP_SIZE)); 928 memcpy(p, &sz, 2); 929 p += 2; 930 } 931 932 if (ifo->userclass[0] && 933 !has_option_mask(ifo->nomask, DHO_USERCLASS)) 934 { 935 AREA_CHECK(ifo->userclass[0]); 936 *p++ = DHO_USERCLASS; 937 memcpy(p, ifo->userclass, 938 (size_t)ifo->userclass[0] + 1); 939 p += ifo->userclass[0] + 1; 940 } 941 } 942 943 if (state->clientid) { 944 AREA_CHECK(state->clientid[0]); 945 *p++ = DHO_CLIENTID; 946 memcpy(p, state->clientid, (size_t)state->clientid[0] + 1); 947 p += state->clientid[0] + 1; 948 } 949 950 if (DHCP_DIR(type) && 951 !has_option_mask(ifo->nomask, DHO_VENDORCLASSID) && 952 ifo->vendorclassid[0]) 953 { 954 AREA_CHECK(ifo->vendorclassid[0]); 955 *p++ = DHO_VENDORCLASSID; 956 memcpy(p, ifo->vendorclassid, (size_t)ifo->vendorclassid[0]+1); 957 p += ifo->vendorclassid[0] + 1; 958 } 959 960 if (type == DHCP_DISCOVER && 961 !(ifp->ctx->options & DHCPCD_TEST) && 962 DHC_REQ(ifo->requestmask, ifo->nomask, DHO_RAPIDCOMMIT)) 963 { 964 /* RFC 4039 Section 3 */ 965 AREA_CHECK(0); 966 *p++ = DHO_RAPIDCOMMIT; 967 *p++ = 0; 968 } 969 970 if (DHCP_DIR(type)) { 971 hostname = dhcp_get_hostname(hbuf, sizeof(hbuf), ifo); 972 973 /* 974 * RFC4702 3.1 States that if we send the Client FQDN option 975 * then we MUST NOT also send the Host Name option. 976 * Technically we could, but that is not RFC conformant and 977 * also seems to break some DHCP server implemetations such as 978 * Windows. On the other hand, ISC dhcpd is just as non RFC 979 * conformant by not accepting a partially qualified FQDN. 980 */ 981 if (ifo->fqdn != FQDN_DISABLE) { 982 /* IETF DHC-FQDN option (81), RFC4702 */ 983 i = 3; 984 if (hostname) 985 i += encode_rfc1035(hostname, NULL); 986 AREA_CHECK(i); 987 *p++ = DHO_FQDN; 988 *p++ = (uint8_t)i; 989 /* 990 * Flags: 0000NEOS 991 * S: 1 => Client requests Server to update 992 * a RR in DNS as well as PTR 993 * O: 1 => Server indicates to client that 994 * DNS has been updated 995 * E: 1 => Name data is DNS format 996 * N: 1 => Client requests Server to not 997 * update DNS 998 */ 999 if (hostname) 1000 *p++ = (uint8_t)((ifo->fqdn & 0x09) | 0x04); 1001 else 1002 *p++ = (FQDN_NONE & 0x09) | 0x04; 1003 *p++ = 0; /* from server for PTR RR */ 1004 *p++ = 0; /* from server for A RR if S=1 */ 1005 if (hostname) { 1006 i = encode_rfc1035(hostname, p); 1007 p += i; 1008 } 1009 } else if (ifo->options & DHCPCD_HOSTNAME && hostname) { 1010 len = strlen(hostname); 1011 AREA_CHECK(len); 1012 *p++ = DHO_HOSTNAME; 1013 *p++ = (uint8_t)len; 1014 memcpy(p, hostname, len); 1015 p += len; 1016 } 1017 } 1018 1019 #ifdef AUTH 1020 auth = NULL; /* appease GCC */ 1021 auth_len = 0; 1022 if (ifo->auth.options & DHCPCD_AUTH_SEND) { 1023 ssize_t alen = dhcp_auth_encode(ifp->ctx, &ifo->auth, 1024 state->auth.token, 1025 NULL, 0, 4, type, NULL, 0); 1026 if (alen != -1 && alen > UINT8_MAX) { 1027 errno = ERANGE; 1028 alen = -1; 1029 } 1030 if (alen == -1) 1031 logerr("%s: dhcp_auth_encode", ifp->name); 1032 else if (alen != 0) { 1033 auth_len = (uint8_t)alen; 1034 AREA_CHECK(auth_len); 1035 *p++ = DHO_AUTHENTICATION; 1036 *p++ = auth_len; 1037 auth = p; 1038 p += auth_len; 1039 } 1040 } 1041 #endif 1042 1043 /* RFC 2563 Auto Configure */ 1044 if (type == DHCP_DISCOVER && ifo->options & DHCPCD_IPV4LL && 1045 !(has_option_mask(ifo->nomask, DHO_AUTOCONFIGURE))) 1046 { 1047 AREA_CHECK(1); 1048 *p++ = DHO_AUTOCONFIGURE; 1049 *p++ = 1; 1050 *p++ = 1; 1051 } 1052 1053 if (DHCP_DIR(type)) { 1054 if (ifo->mudurl[0]) { 1055 AREA_CHECK(ifo->mudurl[0]); 1056 *p++ = DHO_MUDURL; 1057 memcpy(p, ifo->mudurl, (size_t)ifo->mudurl[0] + 1); 1058 p += ifo->mudurl[0] + 1; 1059 } 1060 1061 if (ifo->vivco_len && 1062 !has_option_mask(ifo->nomask, DHO_VIVCO)) 1063 { 1064 AREA_CHECK(sizeof(ul)); 1065 *p++ = DHO_VIVCO; 1066 lp = p++; 1067 *lp = sizeof(ul); 1068 ul = htonl(ifo->vivco_en); 1069 memcpy(p, &ul, sizeof(ul)); 1070 p += sizeof(ul); 1071 for (i = 0, vivco = ifo->vivco; 1072 i < ifo->vivco_len; 1073 i++, vivco++) 1074 { 1075 AREA_FIT(vivco->len); 1076 if (vivco->len + 2 + *lp > 255) { 1077 logerrx("%s: VIVCO option too big", 1078 ifp->name); 1079 free(bootp); 1080 return -1; 1081 } 1082 *p++ = (uint8_t)vivco->len; 1083 memcpy(p, vivco->data, vivco->len); 1084 p += vivco->len; 1085 *lp = (uint8_t)(*lp + vivco->len + 1); 1086 } 1087 } 1088 1089 #ifdef AUTH 1090 if ((ifo->auth.options & DHCPCD_AUTH_SENDREQUIRE) != 1091 DHCPCD_AUTH_SENDREQUIRE && 1092 !has_option_mask(ifo->nomask, DHO_FORCERENEW_NONCE)) 1093 { 1094 /* We support HMAC-MD5 */ 1095 AREA_CHECK(1); 1096 *p++ = DHO_FORCERENEW_NONCE; 1097 *p++ = 1; 1098 *p++ = AUTH_ALG_HMAC_MD5; 1099 } 1100 #endif 1101 } 1102 1103 *p++ = DHO_END; 1104 len = (size_t)(p - (uint8_t *)bootp); 1105 1106 /* Pad out to the BOOTP message length. 1107 * Even if we send a DHCP packet with a variable length vendor area, 1108 * some servers / relay agents don't like packets smaller than 1109 * a BOOTP message which is fine because that's stipulated 1110 * in RFC1542 section 2.1. */ 1111 while (len < sizeof(*bootp)) { 1112 *p++ = DHO_PAD; 1113 len++; 1114 } 1115 1116 #ifdef AUTH 1117 if (ifo->auth.options & DHCPCD_AUTH_SEND && auth_len != 0) 1118 dhcp_auth_encode(ifp->ctx, &ifo->auth, state->auth.token, 1119 (uint8_t *)bootp, len, 4, type, auth, auth_len); 1120 #endif 1121 1122 return (ssize_t)len; 1123 1124 toobig: 1125 logerrx("%s: DHCP message too big", ifp->name); 1126 free(bootp); 1127 return -1; 1128 } 1129 1130 static size_t 1131 read_lease(struct interface *ifp, struct bootp **bootp) 1132 { 1133 union { 1134 struct bootp bootp; 1135 uint8_t buf[FRAMELEN_MAX]; 1136 } buf; 1137 struct dhcp_state *state = D_STATE(ifp); 1138 ssize_t sbytes; 1139 size_t bytes; 1140 uint8_t type; 1141 #ifdef AUTH 1142 const uint8_t *auth; 1143 size_t auth_len; 1144 #endif 1145 1146 /* Safety */ 1147 *bootp = NULL; 1148 1149 if (state->leasefile[0] == '\0') { 1150 logdebugx("reading standard input"); 1151 sbytes = read(fileno(stdin), buf.buf, sizeof(buf.buf)); 1152 } else { 1153 logdebugx("%s: reading lease: %s", 1154 ifp->name, state->leasefile); 1155 sbytes = dhcp_readfile(ifp->ctx, state->leasefile, 1156 buf.buf, sizeof(buf.buf)); 1157 } 1158 if (sbytes == -1) { 1159 if (errno != ENOENT) 1160 logerr("%s: %s", ifp->name, state->leasefile); 1161 return 0; 1162 } 1163 bytes = (size_t)sbytes; 1164 1165 /* Ensure the packet is at lease BOOTP sized 1166 * with a vendor area of 4 octets 1167 * (it should be more, and our read packet enforces this so this 1168 * code should not be needed, but of course people could 1169 * scribble whatever in the stored lease file. */ 1170 if (bytes < DHCP_MIN_LEN) { 1171 logerrx("%s: %s: truncated lease", ifp->name, __func__); 1172 return 0; 1173 } 1174 1175 if (ifp->ctx->options & DHCPCD_DUMPLEASE) 1176 goto out; 1177 1178 /* We may have found a BOOTP server */ 1179 if (get_option_uint8(ifp->ctx, &type, &buf.bootp, bytes, 1180 DHO_MESSAGETYPE) == -1) 1181 type = 0; 1182 1183 #ifdef AUTH 1184 /* Authenticate the message */ 1185 auth = get_option(ifp->ctx, &buf.bootp, bytes, 1186 DHO_AUTHENTICATION, &auth_len); 1187 if (auth) { 1188 if (dhcp_auth_validate(&state->auth, &ifp->options->auth, 1189 &buf.bootp, bytes, 4, type, auth, auth_len) == NULL) 1190 { 1191 logerr("%s: authentication failed", ifp->name); 1192 return 0; 1193 } 1194 if (state->auth.token) 1195 logdebugx("%s: validated using 0x%08" PRIu32, 1196 ifp->name, state->auth.token->secretid); 1197 else 1198 logdebugx("%s: accepted reconfigure key", ifp->name); 1199 } else if ((ifp->options->auth.options & DHCPCD_AUTH_SENDREQUIRE) == 1200 DHCPCD_AUTH_SENDREQUIRE) 1201 { 1202 logerrx("%s: authentication now required", ifp->name); 1203 return 0; 1204 } 1205 #endif 1206 1207 out: 1208 *bootp = malloc(bytes); 1209 if (*bootp == NULL) { 1210 logerr(__func__); 1211 return 0; 1212 } 1213 memcpy(*bootp, buf.buf, bytes); 1214 return bytes; 1215 } 1216 1217 static const struct dhcp_opt * 1218 dhcp_getoverride(const struct if_options *ifo, unsigned int o) 1219 { 1220 size_t i; 1221 const struct dhcp_opt *opt; 1222 1223 for (i = 0, opt = ifo->dhcp_override; 1224 i < ifo->dhcp_override_len; 1225 i++, opt++) 1226 { 1227 if (opt->option == o) 1228 return opt; 1229 } 1230 return NULL; 1231 } 1232 1233 static const uint8_t * 1234 dhcp_getoption(struct dhcpcd_ctx *ctx, 1235 size_t *os, unsigned int *code, size_t *len, 1236 const uint8_t *od, size_t ol, struct dhcp_opt **oopt) 1237 { 1238 size_t i; 1239 struct dhcp_opt *opt; 1240 1241 if (od) { 1242 if (ol < 2) { 1243 errno = EINVAL; 1244 return NULL; 1245 } 1246 *os = 2; /* code + len */ 1247 *code = (unsigned int)*od++; 1248 *len = (size_t)*od++; 1249 if (*len > ol - *os) { 1250 errno = ERANGE; 1251 return NULL; 1252 } 1253 } 1254 1255 *oopt = NULL; 1256 for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) { 1257 if (opt->option == *code) { 1258 *oopt = opt; 1259 break; 1260 } 1261 } 1262 1263 return od; 1264 } 1265 1266 ssize_t 1267 dhcp_env(FILE *fenv, const char *prefix, const struct interface *ifp, 1268 const struct bootp *bootp, size_t bootp_len) 1269 { 1270 const struct if_options *ifo; 1271 const uint8_t *p; 1272 struct in_addr addr; 1273 struct in_addr net; 1274 struct in_addr brd; 1275 struct dhcp_opt *opt, *vo; 1276 size_t i, pl; 1277 char safe[(BOOTP_FILE_LEN * 4) + 1]; 1278 uint8_t overl = 0; 1279 uint32_t en; 1280 1281 ifo = ifp->options; 1282 if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len, 1283 DHO_OPTSOVERLOADED) == -1) 1284 overl = 0; 1285 1286 if (bootp->yiaddr || bootp->ciaddr) { 1287 /* Set some useful variables that we derive from the DHCP 1288 * message but are not necessarily in the options */ 1289 addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr; 1290 if (efprintf(fenv, "%s_ip_address=%s", 1291 prefix, inet_ntoa(addr)) == -1) 1292 return -1; 1293 if (get_option_addr(ifp->ctx, &net, 1294 bootp, bootp_len, DHO_SUBNETMASK) == -1) { 1295 net.s_addr = ipv4_getnetmask(addr.s_addr); 1296 if (efprintf(fenv, "%s_subnet_mask=%s", 1297 prefix, inet_ntoa(net)) == -1) 1298 return -1; 1299 } 1300 if (efprintf(fenv, "%s_subnet_cidr=%d", 1301 prefix, inet_ntocidr(net))== -1) 1302 return -1; 1303 if (get_option_addr(ifp->ctx, &brd, 1304 bootp, bootp_len, DHO_BROADCAST) == -1) 1305 { 1306 brd.s_addr = addr.s_addr | ~net.s_addr; 1307 if (efprintf(fenv, "%s_broadcast_address=%s", 1308 prefix, inet_ntoa(brd)) == -1) 1309 return -1; 1310 } 1311 addr.s_addr = bootp->yiaddr & net.s_addr; 1312 if (efprintf(fenv, "%s_network_number=%s", 1313 prefix, inet_ntoa(addr)) == -1) 1314 return -1; 1315 } 1316 1317 if (*bootp->file && !(overl & 1)) { 1318 print_string(safe, sizeof(safe), OT_STRING, 1319 bootp->file, sizeof(bootp->file)); 1320 if (efprintf(fenv, "%s_filename=%s", prefix, safe) == -1) 1321 return -1; 1322 } 1323 if (*bootp->sname && !(overl & 2)) { 1324 print_string(safe, sizeof(safe), OT_STRING | OT_DOMAIN, 1325 bootp->sname, sizeof(bootp->sname)); 1326 if (efprintf(fenv, "%s_server_name=%s", prefix, safe) == -1) 1327 return -1; 1328 } 1329 1330 /* Zero our indexes */ 1331 for (i = 0, opt = ifp->ctx->dhcp_opts; 1332 i < ifp->ctx->dhcp_opts_len; 1333 i++, opt++) 1334 dhcp_zero_index(opt); 1335 for (i = 0, opt = ifp->options->dhcp_override; 1336 i < ifp->options->dhcp_override_len; 1337 i++, opt++) 1338 dhcp_zero_index(opt); 1339 for (i = 0, opt = ifp->ctx->vivso; 1340 i < ifp->ctx->vivso_len; 1341 i++, opt++) 1342 dhcp_zero_index(opt); 1343 1344 for (i = 0, opt = ifp->ctx->dhcp_opts; 1345 i < ifp->ctx->dhcp_opts_len; 1346 i++, opt++) 1347 { 1348 if (has_option_mask(ifo->nomask, opt->option)) 1349 continue; 1350 if (dhcp_getoverride(ifo, opt->option)) 1351 continue; 1352 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl); 1353 if (p == NULL) 1354 continue; 1355 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name, 1356 opt, dhcp_getoption, p, pl); 1357 1358 if (opt->option != DHO_VIVSO || pl <= (int)sizeof(uint32_t)) 1359 continue; 1360 memcpy(&en, p, sizeof(en)); 1361 en = ntohl(en); 1362 vo = vivso_find(en, ifp); 1363 if (vo == NULL) 1364 continue; 1365 /* Skip over en + total size */ 1366 p += sizeof(en) + 1; 1367 pl -= sizeof(en) + 1; 1368 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name, 1369 vo, dhcp_getoption, p, pl); 1370 } 1371 1372 for (i = 0, opt = ifo->dhcp_override; 1373 i < ifo->dhcp_override_len; 1374 i++, opt++) 1375 { 1376 if (has_option_mask(ifo->nomask, opt->option)) 1377 continue; 1378 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl); 1379 if (p == NULL) 1380 continue; 1381 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name, 1382 opt, dhcp_getoption, p, pl); 1383 } 1384 1385 return 1; 1386 } 1387 1388 static void 1389 get_lease(struct interface *ifp, 1390 struct dhcp_lease *lease, const struct bootp *bootp, size_t len) 1391 { 1392 struct dhcpcd_ctx *ctx; 1393 1394 assert(bootp != NULL); 1395 1396 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie)); 1397 /* BOOTP does not set yiaddr for replies when ciaddr is set. */ 1398 lease->addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr; 1399 ctx = ifp->ctx; 1400 if (ifp->options->options & (DHCPCD_STATIC | DHCPCD_INFORM)) { 1401 if (ifp->options->req_addr.s_addr != INADDR_ANY) { 1402 lease->mask = ifp->options->req_mask; 1403 if (ifp->options->req_brd.s_addr != INADDR_ANY) 1404 lease->brd = ifp->options->req_brd; 1405 else 1406 lease->brd.s_addr = 1407 lease->addr.s_addr | ~lease->mask.s_addr; 1408 } else { 1409 const struct ipv4_addr *ia; 1410 1411 ia = ipv4_iffindaddr(ifp, &lease->addr, NULL); 1412 assert(ia != NULL); 1413 lease->mask = ia->mask; 1414 lease->brd = ia->brd; 1415 } 1416 } else { 1417 if (get_option_addr(ctx, &lease->mask, bootp, len, 1418 DHO_SUBNETMASK) == -1) 1419 lease->mask.s_addr = 1420 ipv4_getnetmask(lease->addr.s_addr); 1421 if (get_option_addr(ctx, &lease->brd, bootp, len, 1422 DHO_BROADCAST) == -1) 1423 lease->brd.s_addr = 1424 lease->addr.s_addr | ~lease->mask.s_addr; 1425 } 1426 if (get_option_uint32(ctx, &lease->leasetime, 1427 bootp, len, DHO_LEASETIME) != 0) 1428 lease->leasetime = DHCP_INFINITE_LIFETIME; 1429 if (get_option_uint32(ctx, &lease->renewaltime, 1430 bootp, len, DHO_RENEWALTIME) != 0) 1431 lease->renewaltime = 0; 1432 if (get_option_uint32(ctx, &lease->rebindtime, 1433 bootp, len, DHO_REBINDTIME) != 0) 1434 lease->rebindtime = 0; 1435 if (get_option_addr(ctx, &lease->server, bootp, len, DHO_SERVERID) != 0) 1436 lease->server.s_addr = INADDR_ANY; 1437 } 1438 1439 static const char * 1440 get_dhcp_op(uint8_t type) 1441 { 1442 const struct dhcp_op *d; 1443 1444 for (d = dhcp_ops; d->name; d++) 1445 if (d->value == type) 1446 return d->name; 1447 return NULL; 1448 } 1449 1450 static void 1451 dhcp_fallback(void *arg) 1452 { 1453 struct interface *iface; 1454 1455 iface = (struct interface *)arg; 1456 dhcpcd_selectprofile(iface, iface->options->fallback); 1457 dhcpcd_startinterface(iface); 1458 } 1459 1460 static void 1461 dhcp_new_xid(struct interface *ifp) 1462 { 1463 struct dhcp_state *state; 1464 const struct interface *ifp1; 1465 const struct dhcp_state *state1; 1466 1467 state = D_STATE(ifp); 1468 if (ifp->options->options & DHCPCD_XID_HWADDR && 1469 ifp->hwlen >= sizeof(state->xid)) 1470 /* The lower bits are probably more unique on the network */ 1471 memcpy(&state->xid, 1472 (ifp->hwaddr + ifp->hwlen) - sizeof(state->xid), 1473 sizeof(state->xid)); 1474 else { 1475 again: 1476 state->xid = arc4random(); 1477 } 1478 1479 /* Ensure it's unique */ 1480 TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) { 1481 if (ifp == ifp1) 1482 continue; 1483 if ((state1 = D_CSTATE(ifp1)) == NULL) 1484 continue; 1485 if (state1->xid == state->xid) 1486 break; 1487 } 1488 if (ifp1 != NULL) { 1489 if (ifp->options->options & DHCPCD_XID_HWADDR && 1490 ifp->hwlen >= sizeof(state->xid)) 1491 { 1492 logerrx("%s: duplicate xid on %s", 1493 ifp->name, ifp1->name); 1494 return; 1495 } 1496 goto again; 1497 } 1498 1499 /* We can't do this when sharing leases across interfaes */ 1500 #if 0 1501 /* As the XID changes, re-apply the filter. */ 1502 if (state->bpf_fd != -1) { 1503 if (bpf_bootp(ifp, state->bpf_fd) == -1) 1504 logerr(__func__); /* try to continue */ 1505 } 1506 #endif 1507 } 1508 1509 static void 1510 dhcp_closebpf(struct interface *ifp) 1511 { 1512 struct dhcpcd_ctx *ctx = ifp->ctx; 1513 struct dhcp_state *state = D_STATE(ifp); 1514 1515 #ifdef PRIVSEP 1516 if (IN_PRIVSEP_SE(ctx)) 1517 ps_bpf_closebootp(ifp); 1518 #endif 1519 1520 if (state->bpf != NULL) { 1521 eloop_event_delete(ctx->eloop, state->bpf->bpf_fd); 1522 bpf_close(state->bpf); 1523 state->bpf = NULL; 1524 } 1525 } 1526 1527 static void 1528 dhcp_closeinet(struct interface *ifp) 1529 { 1530 struct dhcpcd_ctx *ctx = ifp->ctx; 1531 struct dhcp_state *state = D_STATE(ifp); 1532 1533 #ifdef PRIVSEP 1534 if (IN_PRIVSEP_SE(ctx)) { 1535 if (state->addr != NULL) 1536 ps_inet_closebootp(state->addr); 1537 } 1538 #endif 1539 1540 if (state->udp_rfd != -1) { 1541 eloop_event_delete(ctx->eloop, state->udp_rfd); 1542 close(state->udp_rfd); 1543 state->udp_rfd = -1; 1544 } 1545 } 1546 1547 void 1548 dhcp_close(struct interface *ifp) 1549 { 1550 struct dhcp_state *state = D_STATE(ifp); 1551 1552 if (state == NULL) 1553 return; 1554 1555 dhcp_closebpf(ifp); 1556 dhcp_closeinet(ifp); 1557 1558 state->interval = 0; 1559 } 1560 1561 int 1562 dhcp_openudp(struct in_addr *ia) 1563 { 1564 int s; 1565 struct sockaddr_in sin; 1566 int n; 1567 1568 if ((s = xsocket(PF_INET, SOCK_DGRAM | SOCK_CXNB, IPPROTO_UDP)) == -1) 1569 return -1; 1570 1571 n = 1; 1572 if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &n, sizeof(n)) == -1) 1573 goto errexit; 1574 #ifdef IP_RECVIF 1575 if (setsockopt(s, IPPROTO_IP, IP_RECVIF, &n, sizeof(n)) == -1) 1576 goto errexit; 1577 #else 1578 if (setsockopt(s, IPPROTO_IP, IP_RECVPKTINFO, &n, sizeof(n)) == -1) 1579 goto errexit; 1580 #endif 1581 #ifdef SO_RERROR 1582 if (setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)) == -1) 1583 goto errexit; 1584 #endif 1585 1586 memset(&sin, 0, sizeof(sin)); 1587 sin.sin_family = AF_INET; 1588 sin.sin_port = htons(BOOTPC); 1589 if (ia != NULL) 1590 sin.sin_addr = *ia; 1591 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) == -1) 1592 goto errexit; 1593 1594 return s; 1595 1596 errexit: 1597 close(s); 1598 return -1; 1599 } 1600 1601 static uint16_t 1602 in_cksum(const void *data, size_t len, uint32_t *isum) 1603 { 1604 const uint16_t *word = data; 1605 uint32_t sum = isum != NULL ? *isum : 0; 1606 1607 for (; len > 1; len -= sizeof(*word)) 1608 sum += *word++; 1609 1610 if (len == 1) 1611 sum += htons((uint16_t)(*(const uint8_t *)word << 8)); 1612 1613 if (isum != NULL) 1614 *isum = sum; 1615 1616 sum = (sum >> 16) + (sum & 0xffff); 1617 sum += (sum >> 16); 1618 1619 return (uint16_t)~sum; 1620 } 1621 1622 static struct bootp_pkt * 1623 dhcp_makeudppacket(size_t *sz, const uint8_t *data, size_t length, 1624 struct in_addr source, struct in_addr dest) 1625 { 1626 struct bootp_pkt *udpp; 1627 struct ip *ip; 1628 struct udphdr *udp; 1629 1630 if ((udpp = calloc(1, sizeof(*ip) + sizeof(*udp) + length)) == NULL) 1631 return NULL; 1632 ip = &udpp->ip; 1633 udp = &udpp->udp; 1634 1635 /* OK, this is important :) 1636 * We copy the data to our packet and then create a small part of the 1637 * ip structure and an invalid ip_len (basically udp length). 1638 * We then fill the udp structure and put the checksum 1639 * of the whole packet into the udp checksum. 1640 * Finally we complete the ip structure and ip checksum. 1641 * If we don't do the ordering like so then the udp checksum will be 1642 * broken, so find another way of doing it! */ 1643 1644 memcpy(&udpp->bootp, data, length); 1645 1646 ip->ip_p = IPPROTO_UDP; 1647 ip->ip_src.s_addr = source.s_addr; 1648 if (dest.s_addr == 0) 1649 ip->ip_dst.s_addr = INADDR_BROADCAST; 1650 else 1651 ip->ip_dst.s_addr = dest.s_addr; 1652 1653 udp->uh_sport = htons(BOOTPC); 1654 udp->uh_dport = htons(BOOTPS); 1655 udp->uh_ulen = htons((uint16_t)(sizeof(*udp) + length)); 1656 ip->ip_len = udp->uh_ulen; 1657 udp->uh_sum = in_cksum(udpp, sizeof(*ip) + sizeof(*udp) + length, NULL); 1658 1659 ip->ip_v = IPVERSION; 1660 ip->ip_hl = sizeof(*ip) >> 2; 1661 ip->ip_id = (uint16_t)arc4random_uniform(UINT16_MAX); 1662 ip->ip_ttl = IPDEFTTL; 1663 ip->ip_len = htons((uint16_t)(sizeof(*ip) + sizeof(*udp) + length)); 1664 ip->ip_sum = in_cksum(ip, sizeof(*ip), NULL); 1665 if (ip->ip_sum == 0) 1666 ip->ip_sum = 0xffff; /* RFC 768 */ 1667 1668 *sz = sizeof(*ip) + sizeof(*udp) + length; 1669 return udpp; 1670 } 1671 1672 static ssize_t 1673 dhcp_sendudp(struct interface *ifp, struct in_addr *to, void *data, size_t len) 1674 { 1675 struct sockaddr_in sin = { 1676 .sin_family = AF_INET, 1677 .sin_addr = *to, 1678 .sin_port = htons(BOOTPS), 1679 #ifdef HAVE_SA_LEN 1680 .sin_len = sizeof(sin), 1681 #endif 1682 }; 1683 struct udphdr udp = { 1684 .uh_sport = htons(BOOTPC), 1685 .uh_dport = htons(BOOTPS), 1686 .uh_ulen = htons((uint16_t)(sizeof(udp) + len)), 1687 }; 1688 struct iovec iov[] = { 1689 { .iov_base = &udp, .iov_len = sizeof(udp), }, 1690 { .iov_base = data, .iov_len = len, }, 1691 }; 1692 struct msghdr msg = { 1693 .msg_name = (void *)&sin, 1694 .msg_namelen = sizeof(sin), 1695 .msg_iov = iov, 1696 .msg_iovlen = __arraycount(iov), 1697 }; 1698 struct dhcpcd_ctx *ctx = ifp->ctx; 1699 1700 #ifdef PRIVSEP 1701 if (ctx->options & DHCPCD_PRIVSEP) 1702 return ps_inet_sendbootp(ifp, &msg); 1703 #endif 1704 return sendmsg(ctx->udp_wfd, &msg, 0); 1705 } 1706 1707 static void 1708 send_message(struct interface *ifp, uint8_t type, 1709 void (*callback)(void *)) 1710 { 1711 struct dhcp_state *state = D_STATE(ifp); 1712 struct if_options *ifo = ifp->options; 1713 struct bootp *bootp; 1714 struct bootp_pkt *udp; 1715 size_t len, ulen; 1716 ssize_t r; 1717 struct in_addr from, to; 1718 unsigned int RT; 1719 1720 if (callback == NULL) { 1721 /* No carrier? Don't bother sending the packet. */ 1722 if (!if_is_link_up(ifp)) 1723 return; 1724 logdebugx("%s: sending %s with xid 0x%x", 1725 ifp->name, 1726 ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type), 1727 state->xid); 1728 RT = 0; /* bogus gcc warning */ 1729 } else { 1730 if (state->interval == 0) 1731 state->interval = 4; 1732 else { 1733 state->interval *= 2; 1734 if (state->interval > 64) 1735 state->interval = 64; 1736 } 1737 RT = (state->interval * MSEC_PER_SEC) + 1738 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC); 1739 /* No carrier? Don't bother sending the packet. 1740 * However, we do need to advance the timeout. */ 1741 if (!if_is_link_up(ifp)) 1742 goto fail; 1743 logdebugx("%s: sending %s (xid 0x%x), next in %0.1f seconds", 1744 ifp->name, 1745 ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type), 1746 state->xid, 1747 (float)RT / MSEC_PER_SEC); 1748 } 1749 1750 r = make_message(&bootp, ifp, type); 1751 if (r == -1) 1752 goto fail; 1753 len = (size_t)r; 1754 1755 if (!(state->added & (STATE_FAKE | STATE_EXPIRED)) && 1756 state->addr != NULL && 1757 ipv4_iffindaddr(ifp, &state->lease.addr, NULL) != NULL) 1758 from.s_addr = state->lease.addr.s_addr; 1759 else 1760 from.s_addr = INADDR_ANY; 1761 if (from.s_addr != INADDR_ANY && 1762 state->lease.server.s_addr != INADDR_ANY) 1763 to.s_addr = state->lease.server.s_addr; 1764 else 1765 to.s_addr = INADDR_BROADCAST; 1766 1767 /* 1768 * If not listening on the unspecified address we can 1769 * only receive broadcast messages via BPF. 1770 * Sockets bound to an address cannot receive broadcast messages 1771 * even if they are setup to send them. 1772 * Broadcasting from UDP is only an optimisation for rebinding 1773 * and on BSD, at least, is reliant on the subnet route being 1774 * correctly configured to receive the unicast reply. 1775 * As such, we always broadcast and receive the reply to it via BPF. 1776 * This also guarantees we have a DHCP server attached to the 1777 * interface we want to configure because we can't dictate the 1778 * interface via IP_PKTINFO unlike for IPv6. 1779 */ 1780 if (to.s_addr != INADDR_BROADCAST) { 1781 if (dhcp_sendudp(ifp, &to, bootp, len) != -1) 1782 goto out; 1783 logerr("%s: dhcp_sendudp", ifp->name); 1784 } 1785 1786 if (dhcp_openbpf(ifp) == -1) 1787 goto out; 1788 1789 udp = dhcp_makeudppacket(&ulen, (uint8_t *)bootp, len, from, to); 1790 if (udp == NULL) { 1791 logerr("%s: dhcp_makeudppacket", ifp->name); 1792 r = 0; 1793 #ifdef PRIVSEP 1794 } else if (ifp->ctx->options & DHCPCD_PRIVSEP) { 1795 r = ps_bpf_sendbootp(ifp, udp, ulen); 1796 free(udp); 1797 #endif 1798 } else { 1799 r = bpf_send(state->bpf, ETHERTYPE_IP, udp, ulen); 1800 free(udp); 1801 } 1802 /* If we failed to send a raw packet this normally means 1803 * we don't have the ability to work beneath the IP layer 1804 * for this interface. 1805 * As such we remove it from consideration without actually 1806 * stopping the interface. */ 1807 if (r == -1) { 1808 logerr("%s: bpf_send", ifp->name); 1809 switch(errno) { 1810 case ENETDOWN: 1811 case ENETRESET: 1812 case ENETUNREACH: 1813 case ENOBUFS: 1814 break; 1815 default: 1816 if (!(ifp->ctx->options & DHCPCD_TEST)) 1817 dhcp_drop(ifp, "FAIL"); 1818 eloop_timeout_delete(ifp->ctx->eloop, 1819 NULL, ifp); 1820 callback = NULL; 1821 } 1822 } 1823 1824 out: 1825 free(bootp); 1826 1827 fail: 1828 /* Even if we fail to send a packet we should continue as we are 1829 * as our failure timeouts will change out codepath when needed. */ 1830 if (callback != NULL) 1831 eloop_timeout_add_msec(ifp->ctx->eloop, RT, callback, ifp); 1832 } 1833 1834 static void 1835 send_inform(void *arg) 1836 { 1837 1838 send_message((struct interface *)arg, DHCP_INFORM, send_inform); 1839 } 1840 1841 static void 1842 send_discover(void *arg) 1843 { 1844 1845 send_message((struct interface *)arg, DHCP_DISCOVER, send_discover); 1846 } 1847 1848 static void 1849 send_request(void *arg) 1850 { 1851 1852 send_message((struct interface *)arg, DHCP_REQUEST, send_request); 1853 } 1854 1855 static void 1856 send_renew(void *arg) 1857 { 1858 1859 send_message((struct interface *)arg, DHCP_REQUEST, send_renew); 1860 } 1861 1862 static void 1863 send_rebind(void *arg) 1864 { 1865 1866 send_message((struct interface *)arg, DHCP_REQUEST, send_rebind); 1867 } 1868 1869 void 1870 dhcp_discover(void *arg) 1871 { 1872 struct interface *ifp = arg; 1873 struct dhcp_state *state = D_STATE(ifp); 1874 struct if_options *ifo = ifp->options; 1875 1876 state->state = DHS_DISCOVER; 1877 dhcp_new_xid(ifp); 1878 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 1879 if (!(state->added & STATE_EXPIRED)) { 1880 if (ifo->fallback) 1881 eloop_timeout_add_sec(ifp->ctx->eloop, 1882 ifo->reboot, dhcp_fallback, ifp); 1883 #ifdef IPV4LL 1884 else if (ifo->options & DHCPCD_IPV4LL) 1885 eloop_timeout_add_sec(ifp->ctx->eloop, 1886 ifo->reboot, ipv4ll_start, ifp); 1887 #endif 1888 } 1889 if (ifo->options & DHCPCD_REQUEST) 1890 loginfox("%s: soliciting a DHCP lease (requesting %s)", 1891 ifp->name, inet_ntoa(ifo->req_addr)); 1892 else 1893 loginfox("%s: soliciting a %s lease", 1894 ifp->name, ifo->options & DHCPCD_BOOTP ? "BOOTP" : "DHCP"); 1895 send_discover(ifp); 1896 } 1897 1898 static void 1899 dhcp_request(void *arg) 1900 { 1901 struct interface *ifp = arg; 1902 struct dhcp_state *state = D_STATE(ifp); 1903 1904 state->state = DHS_REQUEST; 1905 send_request(ifp); 1906 } 1907 1908 static void 1909 dhcp_expire(void *arg) 1910 { 1911 struct interface *ifp = arg; 1912 struct dhcp_state *state = D_STATE(ifp); 1913 1914 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) { 1915 logwarnx("%s: DHCP lease expired, extending lease", ifp->name); 1916 state->added |= STATE_EXPIRED; 1917 } else { 1918 logerrx("%s: DHCP lease expired", ifp->name); 1919 dhcp_drop(ifp, "EXPIRE"); 1920 dhcp_unlink(ifp->ctx, state->leasefile); 1921 } 1922 state->interval = 0; 1923 dhcp_discover(ifp); 1924 } 1925 1926 #if defined(ARP) || defined(IN_IFF_DUPLICATED) 1927 static void 1928 dhcp_decline(struct interface *ifp) 1929 { 1930 1931 send_message(ifp, DHCP_DECLINE, NULL); 1932 } 1933 #endif 1934 1935 static void 1936 dhcp_startrenew(void *arg) 1937 { 1938 struct interface *ifp = arg; 1939 struct dhcp_state *state; 1940 struct dhcp_lease *lease; 1941 1942 if ((state = D_STATE(ifp)) == NULL) 1943 return; 1944 1945 /* Only renew in the bound or renew states */ 1946 if (state->state != DHS_BOUND && 1947 state->state != DHS_RENEW) 1948 return; 1949 1950 /* Remove the timeout as the renew may have been forced. */ 1951 eloop_timeout_delete(ifp->ctx->eloop, dhcp_startrenew, ifp); 1952 1953 lease = &state->lease; 1954 logdebugx("%s: renewing lease of %s", ifp->name, 1955 inet_ntoa(lease->addr)); 1956 state->state = DHS_RENEW; 1957 dhcp_new_xid(ifp); 1958 state->interval = 0; 1959 send_renew(ifp); 1960 } 1961 1962 void 1963 dhcp_renew(struct interface *ifp) 1964 { 1965 1966 dhcp_startrenew(ifp); 1967 } 1968 1969 static void 1970 dhcp_rebind(void *arg) 1971 { 1972 struct interface *ifp = arg; 1973 struct dhcp_state *state = D_STATE(ifp); 1974 struct dhcp_lease *lease = &state->lease; 1975 1976 logwarnx("%s: failed to renew DHCP, rebinding", ifp->name); 1977 logdebugx("%s: expire in %"PRIu32" seconds", 1978 ifp->name, lease->leasetime - lease->rebindtime); 1979 state->state = DHS_REBIND; 1980 eloop_timeout_delete(ifp->ctx->eloop, send_renew, ifp); 1981 state->lease.server.s_addr = INADDR_ANY; 1982 state->interval = 0; 1983 ifp->options->options &= ~(DHCPCD_CSR_WARNED | 1984 DHCPCD_ROUTER_HOST_ROUTE_WARNED); 1985 send_rebind(ifp); 1986 } 1987 1988 #if defined(ARP) || defined(IN_IFF_DUPLICATED) 1989 static void 1990 dhcp_finish_dad(struct interface *ifp, struct in_addr *ia) 1991 { 1992 struct dhcp_state *state = D_STATE(ifp); 1993 1994 if (state->state == DHS_BOUND) 1995 return; 1996 if (state->offer == NULL || state->offer->yiaddr != ia->s_addr) 1997 return; 1998 1999 logdebugx("%s: DAD completed for %s", ifp->name, inet_ntoa(*ia)); 2000 if (!(ifp->options->options & DHCPCD_INFORM)) 2001 dhcp_bind(ifp); 2002 #ifndef IN_IFF_DUPLICATED 2003 else { 2004 struct bootp *bootp; 2005 size_t len; 2006 2007 bootp = state->new; 2008 len = state->new_len; 2009 state->new = state->offer; 2010 state->new_len = state->offer_len; 2011 get_lease(ifp, &state->lease, state->new, state->new_len); 2012 ipv4_applyaddr(ifp); 2013 state->new = bootp; 2014 state->new_len = len; 2015 } 2016 #endif 2017 2018 #ifdef IPV4LL 2019 /* Stop IPv4LL now we have a working DHCP address */ 2020 if (!IN_LINKLOCAL(ntohl(ia->s_addr))) 2021 ipv4ll_drop(ifp); 2022 #endif 2023 2024 if (ifp->options->options & DHCPCD_INFORM) 2025 dhcp_inform(ifp); 2026 } 2027 2028 static bool 2029 dhcp_addr_duplicated(struct interface *ifp, struct in_addr *ia) 2030 { 2031 struct dhcp_state *state = D_STATE(ifp); 2032 unsigned long long opts = ifp->options->options; 2033 struct dhcpcd_ctx *ctx = ifp->ctx; 2034 bool deleted = false; 2035 #ifdef IN_IFF_DUPLICATED 2036 struct ipv4_addr *iap; 2037 #endif 2038 2039 if ((state->offer == NULL || state->offer->yiaddr != ia->s_addr) && 2040 !IN_ARE_ADDR_EQUAL(ia, &state->lease.addr)) 2041 return deleted; 2042 2043 /* RFC 2131 3.1.5, Client-server interaction */ 2044 logerrx("%s: DAD detected %s", ifp->name, inet_ntoa(*ia)); 2045 dhcp_unlink(ifp->ctx, state->leasefile); 2046 if (!(opts & DHCPCD_STATIC) && !state->lease.frominfo) 2047 dhcp_decline(ifp); 2048 #ifdef IN_IFF_DUPLICATED 2049 if ((iap = ipv4_iffindaddr(ifp, ia, NULL)) != NULL) { 2050 ipv4_deladdr(iap, 0); 2051 deleted = true; 2052 } 2053 #endif 2054 eloop_timeout_delete(ctx->eloop, NULL, ifp); 2055 if (opts & (DHCPCD_STATIC | DHCPCD_INFORM)) { 2056 state->reason = "EXPIRE"; 2057 script_runreason(ifp, state->reason); 2058 #define NOT_ONLY_SELF (DHCPCD_MANAGER | DHCPCD_IPV6RS | DHCPCD_DHCP6) 2059 if (!(ctx->options & NOT_ONLY_SELF)) 2060 eloop_exit(ifp->ctx->eloop, EXIT_FAILURE); 2061 return deleted; 2062 } 2063 eloop_timeout_add_sec(ifp->ctx->eloop, 2064 DHCP_RAND_MAX, dhcp_discover, ifp); 2065 return deleted; 2066 } 2067 #endif 2068 2069 #ifdef ARP 2070 #ifdef KERNEL_RFC5227 2071 #ifdef ARPING 2072 static void 2073 dhcp_arp_announced(struct arp_state *state) 2074 { 2075 2076 arp_free(state); 2077 } 2078 #endif 2079 #else 2080 static void 2081 dhcp_arp_defend_failed(struct arp_state *astate) 2082 { 2083 struct interface *ifp = astate->iface; 2084 2085 dhcp_drop(ifp, "EXPIRED"); 2086 dhcp_start1(ifp); 2087 } 2088 #endif 2089 2090 #if !defined(KERNEL_RFC5227) || defined(ARPING) 2091 static void dhcp_arp_not_found(struct arp_state *); 2092 2093 static struct arp_state * 2094 dhcp_arp_new(struct interface *ifp, struct in_addr *addr) 2095 { 2096 struct arp_state *astate; 2097 2098 astate = arp_new(ifp, addr); 2099 if (astate == NULL) 2100 return NULL; 2101 2102 astate->found_cb = dhcp_arp_found; 2103 astate->not_found_cb = dhcp_arp_not_found; 2104 #ifdef KERNEL_RFC5227 2105 astate->announced_cb = dhcp_arp_announced; 2106 #else 2107 astate->announced_cb = NULL; 2108 astate->defend_failed_cb = dhcp_arp_defend_failed; 2109 #endif 2110 return astate; 2111 } 2112 #endif 2113 2114 #ifdef ARPING 2115 static int 2116 dhcp_arping(struct interface *ifp) 2117 { 2118 struct dhcp_state *state; 2119 struct if_options *ifo; 2120 struct arp_state *astate; 2121 struct in_addr addr; 2122 2123 state = D_STATE(ifp); 2124 ifo = ifp->options; 2125 2126 if (ifo->arping_len == 0 || state->arping_index > ifo->arping_len) 2127 return 0; 2128 2129 if (state->arping_index + 1 == ifo->arping_len) { 2130 state->arping_index++; 2131 dhcpcd_startinterface(ifp); 2132 return 1; 2133 } 2134 2135 addr.s_addr = ifo->arping[++state->arping_index]; 2136 astate = dhcp_arp_new(ifp, &addr); 2137 if (astate == NULL) { 2138 logerr(__func__); 2139 return -1; 2140 } 2141 arp_probe(astate); 2142 return 1; 2143 } 2144 #endif 2145 2146 #if !defined(KERNEL_RFC5227) || defined(ARPING) 2147 static void 2148 dhcp_arp_not_found(struct arp_state *astate) 2149 { 2150 struct interface *ifp; 2151 2152 ifp = astate->iface; 2153 #ifdef ARPING 2154 if (dhcp_arping(ifp) == 1) { 2155 arp_free(astate); 2156 return; 2157 } 2158 #endif 2159 2160 dhcp_finish_dad(ifp, &astate->addr); 2161 } 2162 2163 static void 2164 dhcp_arp_found(struct arp_state *astate, const struct arp_msg *amsg) 2165 { 2166 struct in_addr addr; 2167 struct interface *ifp = astate->iface; 2168 #ifdef ARPING 2169 struct dhcp_state *state; 2170 struct if_options *ifo; 2171 2172 state = D_STATE(ifp); 2173 2174 ifo = ifp->options; 2175 if (state->arping_index != -1 && 2176 state->arping_index < ifo->arping_len && 2177 amsg && 2178 amsg->sip.s_addr == ifo->arping[state->arping_index]) 2179 { 2180 char buf[HWADDR_LEN * 3]; 2181 2182 hwaddr_ntoa(amsg->sha, ifp->hwlen, buf, sizeof(buf)); 2183 if (dhcpcd_selectprofile(ifp, buf) == -1 && 2184 dhcpcd_selectprofile(ifp, inet_ntoa(amsg->sip)) == -1) 2185 { 2186 /* We didn't find a profile for this 2187 * address or hwaddr, so move to the next 2188 * arping profile */ 2189 dhcp_arp_not_found(astate); 2190 return; 2191 } 2192 arp_free(astate); 2193 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2194 dhcpcd_startinterface(ifp); 2195 return; 2196 } 2197 #else 2198 UNUSED(amsg); 2199 #endif 2200 2201 addr = astate->addr; 2202 arp_free(astate); 2203 dhcp_addr_duplicated(ifp, &addr); 2204 } 2205 #endif 2206 2207 #endif /* ARP */ 2208 2209 void 2210 dhcp_bind(struct interface *ifp) 2211 { 2212 struct dhcpcd_ctx *ctx = ifp->ctx; 2213 struct dhcp_state *state = D_STATE(ifp); 2214 struct if_options *ifo = ifp->options; 2215 struct dhcp_lease *lease = &state->lease; 2216 uint8_t old_state; 2217 2218 state->reason = NULL; 2219 /* If we don't have an offer, we are re-binding a lease on preference, 2220 * normally when two interfaces have a lease matching IP addresses. */ 2221 if (state->offer) { 2222 free(state->old); 2223 state->old = state->new; 2224 state->old_len = state->new_len; 2225 state->new = state->offer; 2226 state->new_len = state->offer_len; 2227 state->offer = NULL; 2228 state->offer_len = 0; 2229 } 2230 get_lease(ifp, lease, state->new, state->new_len); 2231 if (ifo->options & DHCPCD_STATIC) { 2232 loginfox("%s: using static address %s/%d", 2233 ifp->name, inet_ntoa(lease->addr), 2234 inet_ntocidr(lease->mask)); 2235 lease->leasetime = DHCP_INFINITE_LIFETIME; 2236 state->reason = "STATIC"; 2237 } else if (ifo->options & DHCPCD_INFORM) { 2238 loginfox("%s: received approval for %s", 2239 ifp->name, inet_ntoa(lease->addr)); 2240 lease->leasetime = DHCP_INFINITE_LIFETIME; 2241 state->reason = "INFORM"; 2242 } else { 2243 if (lease->frominfo) 2244 state->reason = "TIMEOUT"; 2245 if (lease->leasetime == DHCP_INFINITE_LIFETIME) { 2246 lease->renewaltime = 2247 lease->rebindtime = 2248 lease->leasetime; 2249 loginfox("%s: leased %s for infinity", 2250 ifp->name, inet_ntoa(lease->addr)); 2251 } else { 2252 if (lease->leasetime < DHCP_MIN_LEASE) { 2253 logwarnx("%s: minimum lease is %d seconds", 2254 ifp->name, DHCP_MIN_LEASE); 2255 lease->leasetime = DHCP_MIN_LEASE; 2256 } 2257 if (lease->rebindtime == 0) 2258 lease->rebindtime = 2259 (uint32_t)(lease->leasetime * T2); 2260 else if (lease->rebindtime >= lease->leasetime) { 2261 lease->rebindtime = 2262 (uint32_t)(lease->leasetime * T2); 2263 logwarnx("%s: rebind time greater than lease " 2264 "time, forcing to %"PRIu32" seconds", 2265 ifp->name, lease->rebindtime); 2266 } 2267 if (lease->renewaltime == 0) 2268 lease->renewaltime = 2269 (uint32_t)(lease->leasetime * T1); 2270 else if (lease->renewaltime > lease->rebindtime) { 2271 lease->renewaltime = 2272 (uint32_t)(lease->leasetime * T1); 2273 logwarnx("%s: renewal time greater than " 2274 "rebind time, forcing to %"PRIu32" seconds", 2275 ifp->name, lease->renewaltime); 2276 } 2277 if (state->state == DHS_RENEW && state->addr && 2278 lease->addr.s_addr == state->addr->addr.s_addr && 2279 !(state->added & STATE_FAKE)) 2280 logdebugx("%s: leased %s for %"PRIu32" seconds", 2281 ifp->name, inet_ntoa(lease->addr), 2282 lease->leasetime); 2283 else 2284 loginfox("%s: leased %s for %"PRIu32" seconds", 2285 ifp->name, inet_ntoa(lease->addr), 2286 lease->leasetime); 2287 } 2288 } 2289 if (ctx->options & DHCPCD_TEST) { 2290 state->reason = "TEST"; 2291 script_runreason(ifp, state->reason); 2292 eloop_exit(ctx->eloop, EXIT_SUCCESS); 2293 return; 2294 } 2295 if (state->reason == NULL) { 2296 if (state->old && 2297 !(state->added & (STATE_FAKE | STATE_EXPIRED))) 2298 { 2299 if (state->old->yiaddr == state->new->yiaddr && 2300 lease->server.s_addr && 2301 state->state != DHS_REBIND) 2302 state->reason = "RENEW"; 2303 else 2304 state->reason = "REBIND"; 2305 } else if (state->state == DHS_REBOOT) 2306 state->reason = "REBOOT"; 2307 else 2308 state->reason = "BOUND"; 2309 } 2310 if (lease->leasetime == DHCP_INFINITE_LIFETIME) 2311 lease->renewaltime = lease->rebindtime = lease->leasetime; 2312 else { 2313 eloop_timeout_add_sec(ctx->eloop, 2314 lease->renewaltime, dhcp_startrenew, ifp); 2315 eloop_timeout_add_sec(ctx->eloop, 2316 lease->rebindtime, dhcp_rebind, ifp); 2317 eloop_timeout_add_sec(ctx->eloop, 2318 lease->leasetime, dhcp_expire, ifp); 2319 logdebugx("%s: renew in %"PRIu32" seconds, rebind in %"PRIu32 2320 " seconds", 2321 ifp->name, lease->renewaltime, lease->rebindtime); 2322 } 2323 state->state = DHS_BOUND; 2324 if (!state->lease.frominfo && 2325 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))) { 2326 logdebugx("%s: writing lease: %s", 2327 ifp->name, state->leasefile); 2328 if (dhcp_writefile(ifp->ctx, state->leasefile, 0640, 2329 state->new, state->new_len) == -1) 2330 logerr("dhcp_writefile: %s", state->leasefile); 2331 } 2332 2333 old_state = state->added; 2334 2335 if (!(ifo->options & DHCPCD_CONFIGURE)) { 2336 struct ipv4_addr *ia; 2337 2338 script_runreason(ifp, state->reason); 2339 dhcpcd_daemonise(ifp->ctx); 2340 2341 /* We we are not configuring the address, we need to keep 2342 * the BPF socket open if the address does not exist. */ 2343 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL); 2344 if (ia != NULL) { 2345 state->addr = ia; 2346 state->added = STATE_ADDED; 2347 dhcp_closebpf(ifp); 2348 goto openudp; 2349 } 2350 return; 2351 } 2352 2353 /* Add the address */ 2354 if (ipv4_applyaddr(ifp) == NULL) { 2355 /* There was an error adding the address. 2356 * If we are in oneshot, exit with a failure. */ 2357 if (ctx->options & DHCPCD_ONESHOT) { 2358 loginfox("exiting due to oneshot"); 2359 eloop_exit(ctx->eloop, EXIT_FAILURE); 2360 } 2361 return; 2362 } 2363 2364 /* Close the BPF filter as we can now receive DHCP messages 2365 * on a UDP socket. */ 2366 dhcp_closebpf(ifp); 2367 2368 openudp: 2369 /* If not in manager mode, open an address specific socket. */ 2370 if (ctx->options & DHCPCD_MANAGER || 2371 ifo->options & DHCPCD_STATIC || 2372 (state->old != NULL && 2373 state->old->yiaddr == state->new->yiaddr && 2374 old_state & STATE_ADDED && !(old_state & STATE_FAKE))) 2375 return; 2376 2377 dhcp_closeinet(ifp); 2378 #ifdef PRIVSEP 2379 if (IN_PRIVSEP_SE(ctx)) { 2380 if (ps_inet_openbootp(state->addr) == -1) 2381 logerr(__func__); 2382 return; 2383 } 2384 #endif 2385 2386 state->udp_rfd = dhcp_openudp(&state->addr->addr); 2387 if (state->udp_rfd == -1) { 2388 logerr(__func__); 2389 /* Address sharing without manager mode is not supported. 2390 * It's also possible another DHCP client could be running, 2391 * which is even worse. 2392 * We still need to work, so re-open BPF. */ 2393 dhcp_openbpf(ifp); 2394 return; 2395 } 2396 if (eloop_event_add(ctx->eloop, state->udp_rfd, ELE_READ, 2397 dhcp_handleifudp, ifp) == -1) 2398 logerr("%s: eloop_event_add", __func__); 2399 } 2400 2401 static size_t 2402 dhcp_message_new(struct bootp **bootp, 2403 const struct in_addr *addr, const struct in_addr *mask) 2404 { 2405 uint8_t *p; 2406 uint32_t cookie; 2407 2408 if ((*bootp = calloc(1, sizeof(**bootp))) == NULL) 2409 return 0; 2410 2411 (*bootp)->yiaddr = addr->s_addr; 2412 p = (*bootp)->vend; 2413 2414 cookie = htonl(MAGIC_COOKIE); 2415 memcpy(p, &cookie, sizeof(cookie)); 2416 p += sizeof(cookie); 2417 2418 if (mask->s_addr != INADDR_ANY) { 2419 *p++ = DHO_SUBNETMASK; 2420 *p++ = sizeof(mask->s_addr); 2421 memcpy(p, &mask->s_addr, sizeof(mask->s_addr)); 2422 p+= sizeof(mask->s_addr); 2423 } 2424 2425 *p = DHO_END; 2426 return sizeof(**bootp); 2427 } 2428 2429 #if defined(ARP) || defined(KERNEL_RFC5227) 2430 static int 2431 dhcp_arp_address(struct interface *ifp) 2432 { 2433 struct dhcp_state *state; 2434 struct in_addr addr; 2435 struct ipv4_addr *ia; 2436 2437 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2438 2439 state = D_STATE(ifp); 2440 addr.s_addr = state->offer->yiaddr == INADDR_ANY ? 2441 state->offer->ciaddr : state->offer->yiaddr; 2442 /* If the interface already has the address configured 2443 * then we can't ARP for duplicate detection. */ 2444 ia = ipv4_iffindaddr(ifp, &addr, NULL); 2445 #ifdef IN_IFF_NOTUSEABLE 2446 if (ia == NULL || ia->addr_flags & IN_IFF_NOTUSEABLE) { 2447 state->state = DHS_PROBE; 2448 if (ia == NULL) { 2449 struct dhcp_lease l; 2450 2451 get_lease(ifp, &l, state->offer, state->offer_len); 2452 /* Add the address now, let the kernel handle DAD. */ 2453 ipv4_addaddr(ifp, &l.addr, &l.mask, &l.brd, 2454 l.leasetime, l.rebindtime); 2455 } else if (ia->addr_flags & IN_IFF_DUPLICATED) 2456 dhcp_addr_duplicated(ifp, &ia->addr); 2457 else 2458 loginfox("%s: waiting for DAD on %s", 2459 ifp->name, inet_ntoa(addr)); 2460 return 0; 2461 } 2462 #else 2463 if (!(ifp->flags & IFF_NOARP) && 2464 ifp->options->options & DHCPCD_ARP) 2465 { 2466 struct arp_state *astate; 2467 struct dhcp_lease l; 2468 2469 /* Even if the address exists, we need to defend it. */ 2470 astate = dhcp_arp_new(ifp, &addr); 2471 if (astate == NULL) 2472 return -1; 2473 2474 if (ia == NULL) { 2475 state->state = DHS_PROBE; 2476 get_lease(ifp, &l, state->offer, state->offer_len); 2477 loginfox("%s: probing address %s/%d", 2478 ifp->name, inet_ntoa(l.addr), inet_ntocidr(l.mask)); 2479 /* We need to handle DAD. */ 2480 arp_probe(astate); 2481 return 0; 2482 } 2483 } 2484 #endif 2485 2486 return 1; 2487 } 2488 2489 static void 2490 dhcp_arp_bind(struct interface *ifp) 2491 { 2492 2493 if (ifp->ctx->options & DHCPCD_TEST || 2494 dhcp_arp_address(ifp) == 1) 2495 dhcp_bind(ifp); 2496 } 2497 #endif 2498 2499 static void 2500 dhcp_lastlease(void *arg) 2501 { 2502 struct interface *ifp = arg; 2503 struct dhcp_state *state = D_STATE(ifp); 2504 2505 loginfox("%s: timed out contacting a DHCP server, using last lease", 2506 ifp->name); 2507 #if defined(ARP) || defined(KERNEL_RFC5227) 2508 dhcp_arp_bind(ifp); 2509 #else 2510 dhcp_bind(ifp); 2511 #endif 2512 /* Set expired here because dhcp_bind() -> ipv4_addaddr() will reset 2513 * state */ 2514 state->added |= STATE_EXPIRED; 2515 state->interval = 0; 2516 dhcp_discover(ifp); 2517 } 2518 2519 static void 2520 dhcp_static(struct interface *ifp) 2521 { 2522 struct if_options *ifo; 2523 struct dhcp_state *state; 2524 struct ipv4_addr *ia; 2525 2526 state = D_STATE(ifp); 2527 ifo = ifp->options; 2528 2529 ia = NULL; 2530 if (ifo->req_addr.s_addr == INADDR_ANY && 2531 (ia = ipv4_iffindaddr(ifp, NULL, NULL)) == NULL) 2532 { 2533 loginfox("%s: waiting for 3rd party to " 2534 "configure IP address", ifp->name); 2535 state->reason = "3RDPARTY"; 2536 script_runreason(ifp, state->reason); 2537 return; 2538 } 2539 2540 state->offer_len = dhcp_message_new(&state->offer, 2541 ia ? &ia->addr : &ifo->req_addr, 2542 ia ? &ia->mask : &ifo->req_mask); 2543 if (state->offer_len) 2544 #if defined(ARP) || defined(KERNEL_RFC5227) 2545 dhcp_arp_bind(ifp); 2546 #else 2547 dhcp_bind(ifp); 2548 #endif 2549 } 2550 2551 void 2552 dhcp_inform(struct interface *ifp) 2553 { 2554 struct dhcp_state *state; 2555 struct if_options *ifo; 2556 struct ipv4_addr *ia; 2557 2558 state = D_STATE(ifp); 2559 ifo = ifp->options; 2560 2561 free(state->offer); 2562 state->offer = NULL; 2563 state->offer_len = 0; 2564 2565 if (ifo->req_addr.s_addr == INADDR_ANY) { 2566 ia = ipv4_iffindaddr(ifp, NULL, NULL); 2567 if (ia == NULL) { 2568 loginfox("%s: waiting for 3rd party to " 2569 "configure IP address", 2570 ifp->name); 2571 if (!(ifp->ctx->options & DHCPCD_TEST)) { 2572 state->reason = "3RDPARTY"; 2573 script_runreason(ifp, state->reason); 2574 } 2575 return; 2576 } 2577 } else { 2578 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, &ifo->req_mask); 2579 if (ia == NULL) { 2580 if (ifp->ctx->options & DHCPCD_TEST) { 2581 logerrx("%s: cannot add IP address in test mode", 2582 ifp->name); 2583 return; 2584 } 2585 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, NULL); 2586 if (ia != NULL) 2587 /* Netmask must be different, delete it. */ 2588 ipv4_deladdr(ia, 1); 2589 state->offer_len = dhcp_message_new(&state->offer, 2590 &ifo->req_addr, &ifo->req_mask); 2591 #ifdef ARP 2592 if (dhcp_arp_address(ifp) != 1) 2593 return; 2594 #endif 2595 ia = ipv4_iffindaddr(ifp, 2596 &ifo->req_addr, &ifo->req_mask); 2597 assert(ia != NULL); 2598 } 2599 } 2600 2601 state->state = DHS_INFORM; 2602 state->addr = ia; 2603 state->offer_len = dhcp_message_new(&state->offer, 2604 &ia->addr, &ia->mask); 2605 if (state->offer_len) { 2606 dhcp_new_xid(ifp); 2607 get_lease(ifp, &state->lease, state->offer, state->offer_len); 2608 send_inform(ifp); 2609 } 2610 } 2611 2612 void 2613 dhcp_reboot_newopts(struct interface *ifp, unsigned long long oldopts) 2614 { 2615 struct if_options *ifo; 2616 struct dhcp_state *state = D_STATE(ifp); 2617 2618 if (state == NULL || state->state == DHS_NONE) 2619 return; 2620 ifo = ifp->options; 2621 if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC) && 2622 (state->addr == NULL || 2623 state->addr->addr.s_addr != ifo->req_addr.s_addr)) || 2624 (oldopts & (DHCPCD_INFORM | DHCPCD_STATIC) && 2625 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC)))) 2626 { 2627 dhcp_drop(ifp, "EXPIRE"); 2628 } 2629 } 2630 2631 #ifdef ARP 2632 static int 2633 dhcp_activeaddr(const struct interface *ifp, const struct in_addr *addr) 2634 { 2635 const struct interface *ifp1; 2636 const struct dhcp_state *state; 2637 2638 TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) { 2639 if (ifp1 == ifp) 2640 continue; 2641 if ((state = D_CSTATE(ifp1)) == NULL) 2642 continue; 2643 switch(state->state) { 2644 case DHS_REBOOT: 2645 case DHS_RENEW: 2646 case DHS_REBIND: 2647 case DHS_BOUND: 2648 case DHS_INFORM: 2649 break; 2650 default: 2651 continue; 2652 } 2653 if (state->lease.addr.s_addr == addr->s_addr) 2654 return 1; 2655 } 2656 return 0; 2657 } 2658 #endif 2659 2660 static void 2661 dhcp_reboot(struct interface *ifp) 2662 { 2663 struct if_options *ifo; 2664 struct dhcp_state *state = D_STATE(ifp); 2665 #ifdef ARP 2666 struct ipv4_addr *ia; 2667 #endif 2668 2669 if (state == NULL || state->state == DHS_NONE) 2670 return; 2671 ifo = ifp->options; 2672 state->state = DHS_REBOOT; 2673 state->interval = 0; 2674 2675 if (ifo->options & DHCPCD_LINK && !if_is_link_up(ifp)) { 2676 loginfox("%s: waiting for carrier", ifp->name); 2677 return; 2678 } 2679 if (ifo->options & DHCPCD_STATIC) { 2680 dhcp_static(ifp); 2681 return; 2682 } 2683 if (ifo->options & DHCPCD_INFORM) { 2684 loginfox("%s: informing address of %s", 2685 ifp->name, inet_ntoa(state->lease.addr)); 2686 dhcp_inform(ifp); 2687 return; 2688 } 2689 if (ifo->reboot == 0 || state->offer == NULL) { 2690 dhcp_discover(ifp); 2691 return; 2692 } 2693 if (!IS_DHCP(state->offer)) 2694 return; 2695 2696 loginfox("%s: rebinding lease of %s", 2697 ifp->name, inet_ntoa(state->lease.addr)); 2698 2699 #ifdef ARP 2700 #ifndef KERNEL_RFC5227 2701 /* Create the DHCP ARP state so we can defend it. */ 2702 (void)dhcp_arp_new(ifp, &state->lease.addr); 2703 #endif 2704 2705 /* If the address exists on the interface and no other interface 2706 * is currently using it then announce it to ensure this 2707 * interface gets the reply. */ 2708 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL); 2709 if (ia != NULL && 2710 !(ifp->ctx->options & DHCPCD_TEST) && 2711 #ifdef IN_IFF_NOTUSEABLE 2712 !(ia->addr_flags & IN_IFF_NOTUSEABLE) && 2713 #endif 2714 dhcp_activeaddr(ifp, &state->lease.addr) == 0) 2715 arp_ifannounceaddr(ifp, &state->lease.addr); 2716 #endif 2717 2718 dhcp_new_xid(ifp); 2719 state->lease.server.s_addr = INADDR_ANY; 2720 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2721 2722 #ifdef IPV4LL 2723 /* Need to add this before dhcp_expire and friends. */ 2724 if (!ifo->fallback && ifo->options & DHCPCD_IPV4LL) 2725 eloop_timeout_add_sec(ifp->ctx->eloop, 2726 ifo->reboot, ipv4ll_start, ifp); 2727 #endif 2728 2729 if (ifo->options & DHCPCD_LASTLEASE && state->lease.frominfo) 2730 eloop_timeout_add_sec(ifp->ctx->eloop, 2731 ifo->reboot, dhcp_lastlease, ifp); 2732 else if (!(ifo->options & DHCPCD_INFORM)) 2733 eloop_timeout_add_sec(ifp->ctx->eloop, 2734 ifo->reboot, dhcp_expire, ifp); 2735 2736 /* Don't bother ARP checking as the server could NAK us first. 2737 * Don't call dhcp_request as that would change the state */ 2738 send_request(ifp); 2739 } 2740 2741 void 2742 dhcp_drop(struct interface *ifp, const char *reason) 2743 { 2744 struct dhcp_state *state = D_STATE(ifp); 2745 2746 /* dhcp_start may just have been called and we don't yet have a state 2747 * but we do have a timeout, so punt it. */ 2748 if (state == NULL || state->state == DHS_NONE) { 2749 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2750 return; 2751 } 2752 2753 #ifdef ARP 2754 if (state->addr != NULL) 2755 arp_freeaddr(ifp, &state->addr->addr); 2756 #endif 2757 #ifdef ARPING 2758 state->arping_index = -1; 2759 #endif 2760 2761 if (ifp->options->options & DHCPCD_RELEASE && 2762 !(ifp->options->options & DHCPCD_INFORM)) 2763 { 2764 /* Failure to send the release may cause this function to 2765 * re-enter so guard by setting the state. */ 2766 if (state->state == DHS_RELEASE) 2767 return; 2768 state->state = DHS_RELEASE; 2769 2770 dhcp_unlink(ifp->ctx, state->leasefile); 2771 if (if_is_link_up(ifp) && 2772 state->new != NULL && 2773 state->lease.server.s_addr != INADDR_ANY) 2774 { 2775 loginfox("%s: releasing lease of %s", 2776 ifp->name, inet_ntoa(state->lease.addr)); 2777 dhcp_new_xid(ifp); 2778 send_message(ifp, DHCP_RELEASE, NULL); 2779 } 2780 } 2781 #ifdef AUTH 2782 else if (state->auth.reconf != NULL) { 2783 /* 2784 * Drop the lease as the token may only be present 2785 * in the initial reply message and not subsequent 2786 * renewals. 2787 * If dhcpcd is restarted, the token is lost. 2788 * XXX persist this in another file? 2789 */ 2790 dhcp_unlink(ifp->ctx, state->leasefile); 2791 } 2792 #endif 2793 2794 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2795 #ifdef AUTH 2796 dhcp_auth_reset(&state->auth); 2797 #endif 2798 2799 state->state = DHS_NONE; 2800 free(state->offer); 2801 state->offer = NULL; 2802 state->offer_len = 0; 2803 free(state->old); 2804 state->old = state->new; 2805 state->old_len = state->new_len; 2806 state->new = NULL; 2807 state->new_len = 0; 2808 state->reason = reason; 2809 if (ifp->options->options & DHCPCD_CONFIGURE) 2810 ipv4_applyaddr(ifp); 2811 else { 2812 state->addr = NULL; 2813 state->added = 0; 2814 script_runreason(ifp, state->reason); 2815 } 2816 free(state->old); 2817 state->old = NULL; 2818 state->old_len = 0; 2819 state->lease.addr.s_addr = 0; 2820 ifp->options->options &= ~(DHCPCD_CSR_WARNED | 2821 DHCPCD_ROUTER_HOST_ROUTE_WARNED); 2822 2823 /* Close DHCP ports so a changed interface family is picked 2824 * up by a new BPF state. */ 2825 dhcp_close(ifp); 2826 } 2827 2828 static int 2829 blacklisted_ip(const struct if_options *ifo, in_addr_t addr) 2830 { 2831 size_t i; 2832 2833 for (i = 0; i < ifo->blacklist_len; i += 2) 2834 if (ifo->blacklist[i] == (addr & ifo->blacklist[i + 1])) 2835 return 1; 2836 return 0; 2837 } 2838 2839 #define WHTLST_NONE 0 2840 #define WHTLST_MATCH 1 2841 #define WHTLST_NOMATCH 2 2842 static unsigned int 2843 whitelisted_ip(const struct if_options *ifo, in_addr_t addr) 2844 { 2845 size_t i; 2846 2847 if (ifo->whitelist_len == 0) 2848 return WHTLST_NONE; 2849 for (i = 0; i < ifo->whitelist_len; i += 2) 2850 if (ifo->whitelist[i] == (addr & ifo->whitelist[i + 1])) 2851 return WHTLST_MATCH; 2852 return WHTLST_NOMATCH; 2853 } 2854 2855 static void 2856 log_dhcp(int loglevel, const char *msg, 2857 const struct interface *ifp, const struct bootp *bootp, size_t bootp_len, 2858 const struct in_addr *from, int ad) 2859 { 2860 const char *tfrom; 2861 char *a, sname[sizeof(bootp->sname) * 4]; 2862 struct in_addr addr; 2863 int r; 2864 uint8_t overl; 2865 2866 if (strcmp(msg, "NAK:") == 0) { 2867 a = get_option_string(ifp->ctx, bootp, bootp_len, DHO_MESSAGE); 2868 if (a) { 2869 char *tmp; 2870 size_t al, tmpl; 2871 2872 al = strlen(a); 2873 tmpl = (al * 4) + 1; 2874 tmp = malloc(tmpl); 2875 if (tmp == NULL) { 2876 logerr(__func__); 2877 free(a); 2878 return; 2879 } 2880 print_string(tmp, tmpl, OT_STRING, (uint8_t *)a, al); 2881 free(a); 2882 a = tmp; 2883 } 2884 } else if (ad && bootp->yiaddr != 0) { 2885 addr.s_addr = bootp->yiaddr; 2886 a = strdup(inet_ntoa(addr)); 2887 if (a == NULL) { 2888 logerr(__func__); 2889 return; 2890 } 2891 } else 2892 a = NULL; 2893 2894 tfrom = "from"; 2895 r = get_option_addr(ifp->ctx, &addr, bootp, bootp_len, DHO_SERVERID); 2896 if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len, 2897 DHO_OPTSOVERLOADED) == -1) 2898 overl = 0; 2899 if (bootp->sname[0] && r == 0 && !(overl & 2)) { 2900 print_string(sname, sizeof(sname), OT_STRING | OT_DOMAIN, 2901 bootp->sname, sizeof(bootp->sname)); 2902 if (a == NULL) 2903 logmessage(loglevel, "%s: %s %s %s %s", 2904 ifp->name, msg, tfrom, inet_ntoa(addr), sname); 2905 else 2906 logmessage(loglevel, "%s: %s %s %s %s %s", 2907 ifp->name, msg, a, tfrom, inet_ntoa(addr), sname); 2908 } else { 2909 if (r != 0) { 2910 tfrom = "via"; 2911 addr = *from; 2912 } 2913 if (a == NULL) 2914 logmessage(loglevel, "%s: %s %s %s", 2915 ifp->name, msg, tfrom, inet_ntoa(addr)); 2916 else 2917 logmessage(loglevel, "%s: %s %s %s %s", 2918 ifp->name, msg, a, tfrom, inet_ntoa(addr)); 2919 } 2920 free(a); 2921 } 2922 2923 /* If we're sharing the same IP address with another interface on the 2924 * same network, we may receive the DHCP reply on the wrong interface. 2925 * Try and re-direct it here. */ 2926 static void 2927 dhcp_redirect_dhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len, 2928 const struct in_addr *from) 2929 { 2930 struct interface *ifn; 2931 const struct dhcp_state *state; 2932 uint32_t xid; 2933 2934 xid = ntohl(bootp->xid); 2935 TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) { 2936 if (ifn == ifp) 2937 continue; 2938 state = D_CSTATE(ifn); 2939 if (state == NULL || state->state == DHS_NONE) 2940 continue; 2941 if (state->xid != xid) 2942 continue; 2943 if (ifn->hwlen <= sizeof(bootp->chaddr) && 2944 memcmp(bootp->chaddr, ifn->hwaddr, ifn->hwlen)) 2945 continue; 2946 logdebugx("%s: redirecting DHCP message to %s", 2947 ifp->name, ifn->name); 2948 dhcp_handledhcp(ifn, bootp, bootp_len, from); 2949 } 2950 } 2951 2952 static void 2953 dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len, 2954 const struct in_addr *from) 2955 { 2956 struct dhcp_state *state = D_STATE(ifp); 2957 struct if_options *ifo = ifp->options; 2958 struct dhcp_lease *lease = &state->lease; 2959 uint8_t type, tmp; 2960 struct in_addr addr; 2961 unsigned int i; 2962 char *msg; 2963 bool bootp_copied; 2964 uint32_t v6only_time = 0; 2965 bool use_v6only = false; 2966 #ifdef AUTH 2967 const uint8_t *auth; 2968 size_t auth_len; 2969 #endif 2970 #ifdef IN_IFF_DUPLICATED 2971 struct ipv4_addr *ia; 2972 #endif 2973 2974 #define LOGDHCP0(l, m) \ 2975 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 0) 2976 #define LOGDHCP(l, m) \ 2977 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 1) 2978 2979 #define IS_STATE_ACTIVE(s) ((s)-state != DHS_NONE && \ 2980 (s)->state != DHS_INIT && (s)->state != DHS_BOUND) 2981 2982 if (bootp->op != BOOTREPLY) { 2983 if (IS_STATE_ACTIVE(state)) 2984 logdebugx("%s: op (%d) is not BOOTREPLY", 2985 ifp->name, bootp->op); 2986 return; 2987 } 2988 2989 if (state->xid != ntohl(bootp->xid)) { 2990 if (IS_STATE_ACTIVE(state)) 2991 logdebugx("%s: wrong xid 0x%x (expecting 0x%x) from %s", 2992 ifp->name, ntohl(bootp->xid), state->xid, 2993 inet_ntoa(*from)); 2994 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from); 2995 return; 2996 } 2997 2998 if (ifp->hwlen <= sizeof(bootp->chaddr) && 2999 memcmp(bootp->chaddr, ifp->hwaddr, ifp->hwlen)) 3000 { 3001 if (IS_STATE_ACTIVE(state)) { 3002 char buf[sizeof(bootp->chaddr) * 3]; 3003 3004 logdebugx("%s: xid 0x%x is for hwaddr %s", 3005 ifp->name, ntohl(bootp->xid), 3006 hwaddr_ntoa(bootp->chaddr, sizeof(bootp->chaddr), 3007 buf, sizeof(buf))); 3008 } 3009 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from); 3010 return; 3011 } 3012 3013 if (!ifp->active) 3014 return; 3015 3016 i = whitelisted_ip(ifp->options, from->s_addr); 3017 switch (i) { 3018 case WHTLST_NOMATCH: 3019 logwarnx("%s: non whitelisted DHCP packet from %s", 3020 ifp->name, inet_ntoa(*from)); 3021 return; 3022 case WHTLST_MATCH: 3023 break; 3024 case WHTLST_NONE: 3025 if (blacklisted_ip(ifp->options, from->s_addr) == 1) { 3026 logwarnx("%s: blacklisted DHCP packet from %s", 3027 ifp->name, inet_ntoa(*from)); 3028 return; 3029 } 3030 } 3031 3032 /* We may have found a BOOTP server */ 3033 if (get_option_uint8(ifp->ctx, &type, 3034 bootp, bootp_len, DHO_MESSAGETYPE) == -1) 3035 type = 0; 3036 else if (ifo->options & DHCPCD_BOOTP) { 3037 logdebugx("%s: ignoring DHCP reply (expecting BOOTP)", 3038 ifp->name); 3039 return; 3040 } 3041 3042 #ifdef AUTH 3043 /* Authenticate the message */ 3044 auth = get_option(ifp->ctx, bootp, bootp_len, 3045 DHO_AUTHENTICATION, &auth_len); 3046 if (auth) { 3047 if (dhcp_auth_validate(&state->auth, &ifo->auth, 3048 (uint8_t *)bootp, bootp_len, 4, type, 3049 auth, auth_len) == NULL) 3050 { 3051 LOGDHCP0(LOG_ERR, "authentication failed"); 3052 return; 3053 } 3054 if (state->auth.token) 3055 logdebugx("%s: validated using 0x%08" PRIu32, 3056 ifp->name, state->auth.token->secretid); 3057 else 3058 loginfox("%s: accepted reconfigure key", ifp->name); 3059 } else if (ifo->auth.options & DHCPCD_AUTH_SEND) { 3060 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) { 3061 LOGDHCP0(LOG_ERR, "no authentication"); 3062 return; 3063 } 3064 LOGDHCP0(LOG_WARNING, "no authentication"); 3065 } 3066 #endif 3067 3068 /* RFC 3203 */ 3069 if (type == DHCP_FORCERENEW) { 3070 if (from->s_addr == INADDR_ANY || 3071 from->s_addr == INADDR_BROADCAST) 3072 { 3073 LOGDHCP(LOG_ERR, "discarding Force Renew"); 3074 return; 3075 } 3076 #ifdef AUTH 3077 if (auth == NULL) { 3078 LOGDHCP(LOG_ERR, "unauthenticated Force Renew"); 3079 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) 3080 return; 3081 } 3082 if (state->state != DHS_BOUND && state->state != DHS_INFORM) { 3083 LOGDHCP(LOG_DEBUG, "not bound, ignoring Force Renew"); 3084 return; 3085 } 3086 LOGDHCP(LOG_INFO, "Force Renew from"); 3087 /* The rebind and expire timings are still the same, we just 3088 * enter the renew state early */ 3089 if (state->state == DHS_BOUND) 3090 dhcp_renew(ifp); 3091 else { 3092 eloop_timeout_delete(ifp->ctx->eloop, 3093 send_inform, ifp); 3094 dhcp_inform(ifp); 3095 } 3096 #else 3097 LOGDHCP(LOG_ERR, "unauthenticated Force Renew"); 3098 #endif 3099 return; 3100 } 3101 3102 if (state->state == DHS_BOUND) { 3103 LOGDHCP(LOG_DEBUG, "bound, ignoring"); 3104 return; 3105 } 3106 3107 if (state->state == DHS_PROBE) { 3108 /* Ignore any DHCP messages whilst probing a lease to bind. */ 3109 LOGDHCP(LOG_DEBUG, "probing, ignoring"); 3110 return; 3111 } 3112 3113 /* reset the message counter */ 3114 state->interval = 0; 3115 3116 /* Ensure that no reject options are present */ 3117 for (i = 1; i < 255; i++) { 3118 if (has_option_mask(ifo->rejectmask, i) && 3119 get_option_uint8(ifp->ctx, &tmp, 3120 bootp, bootp_len, (uint8_t)i) == 0) 3121 { 3122 LOGDHCP(LOG_WARNING, "reject DHCP"); 3123 return; 3124 } 3125 } 3126 3127 if (type == DHCP_NAK) { 3128 /* For NAK, only check if we require the ServerID */ 3129 if (has_option_mask(ifo->requiremask, DHO_SERVERID) && 3130 get_option_addr(ifp->ctx, &addr, 3131 bootp, bootp_len, DHO_SERVERID) == -1) 3132 { 3133 LOGDHCP(LOG_WARNING, "reject NAK"); 3134 return; 3135 } 3136 3137 /* We should restart on a NAK */ 3138 LOGDHCP(LOG_WARNING, "NAK:"); 3139 if ((msg = get_option_string(ifp->ctx, 3140 bootp, bootp_len, DHO_MESSAGE))) 3141 { 3142 logwarnx("%s: message: %s", ifp->name, msg); 3143 free(msg); 3144 } 3145 if (state->state == DHS_INFORM) /* INFORM should not be NAKed */ 3146 return; 3147 if (!(ifp->ctx->options & DHCPCD_TEST)) { 3148 dhcp_drop(ifp, "NAK"); 3149 dhcp_unlink(ifp->ctx, state->leasefile); 3150 } 3151 3152 /* If we constantly get NAKS then we should slowly back off */ 3153 eloop_timeout_add_sec(ifp->ctx->eloop, 3154 state->nakoff, dhcp_discover, ifp); 3155 if (state->nakoff == 0) 3156 state->nakoff = 1; 3157 else { 3158 state->nakoff *= 2; 3159 if (state->nakoff > NAKOFF_MAX) 3160 state->nakoff = NAKOFF_MAX; 3161 } 3162 return; 3163 } 3164 3165 /* Ensure that all required options are present */ 3166 for (i = 1; i < 255; i++) { 3167 if (has_option_mask(ifo->requiremask, i) && 3168 get_option_uint8(ifp->ctx, &tmp, 3169 bootp, bootp_len, (uint8_t)i) != 0) 3170 { 3171 /* If we are BOOTP, then ignore the need for serverid. 3172 * To ignore BOOTP, require dhcp_message_type. 3173 * However, nothing really stops BOOTP from providing 3174 * DHCP style options as well so the above isn't 3175 * always true. */ 3176 if (type == 0 && i == DHO_SERVERID) 3177 continue; 3178 LOGDHCP(LOG_WARNING, "reject DHCP"); 3179 return; 3180 } 3181 } 3182 3183 if (has_option_mask(ifo->requestmask, DHO_IPV6_PREFERRED_ONLY)) { 3184 if (get_option_uint32(ifp->ctx, &v6only_time, bootp, bootp_len, 3185 DHO_IPV6_PREFERRED_ONLY) == 0 && 3186 (state->state == DHS_DISCOVER || state->state == DHS_REBOOT)) 3187 { 3188 char v6msg[128]; 3189 3190 use_v6only = true; 3191 if (v6only_time < MIN_V6ONLY_WAIT) 3192 v6only_time = MIN_V6ONLY_WAIT; 3193 snprintf(v6msg, sizeof(v6msg), 3194 "IPv6-Only Preferred received (%u seconds)", 3195 v6only_time); 3196 LOGDHCP(LOG_INFO, v6msg); 3197 } 3198 } 3199 3200 /* DHCP Auto-Configure, RFC 2563 */ 3201 if (type == DHCP_OFFER && bootp->yiaddr == 0) { 3202 LOGDHCP(LOG_WARNING, "no address given"); 3203 if ((msg = get_option_string(ifp->ctx, 3204 bootp, bootp_len, DHO_MESSAGE))) 3205 { 3206 logwarnx("%s: message: %s", ifp->name, msg); 3207 free(msg); 3208 } 3209 #ifdef IPV4LL 3210 if (state->state == DHS_DISCOVER && 3211 get_option_uint8(ifp->ctx, &tmp, bootp, bootp_len, 3212 DHO_AUTOCONFIGURE) == 0) 3213 { 3214 switch (tmp) { 3215 case 0: 3216 LOGDHCP(LOG_WARNING, "IPv4LL disabled from"); 3217 ipv4ll_drop(ifp); 3218 #ifdef ARP 3219 arp_drop(ifp); 3220 #endif 3221 break; 3222 case 1: 3223 LOGDHCP(LOG_WARNING, "IPv4LL enabled from"); 3224 ipv4ll_start(ifp); 3225 break; 3226 default: 3227 logerrx("%s: unknown auto configuration " 3228 "option %d", 3229 ifp->name, tmp); 3230 break; 3231 } 3232 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3233 eloop_timeout_add_sec(ifp->ctx->eloop, 3234 use_v6only ? v6only_time : DHCP_MAX, 3235 dhcp_discover, ifp); 3236 } 3237 #endif 3238 return; 3239 } 3240 3241 if (use_v6only) { 3242 dhcp_drop(ifp, "EXPIRE"); 3243 dhcp_unlink(ifp->ctx, state->leasefile); 3244 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3245 eloop_timeout_add_sec(ifp->ctx->eloop, v6only_time, 3246 dhcp_discover, ifp); 3247 return; 3248 } 3249 3250 /* Ensure that the address offered is valid */ 3251 if ((type == 0 || type == DHCP_OFFER || type == DHCP_ACK) && 3252 (bootp->ciaddr == INADDR_ANY || bootp->ciaddr == INADDR_BROADCAST) 3253 && 3254 (bootp->yiaddr == INADDR_ANY || bootp->yiaddr == INADDR_BROADCAST)) 3255 { 3256 LOGDHCP(LOG_WARNING, "reject invalid address"); 3257 return; 3258 } 3259 3260 #ifdef IN_IFF_DUPLICATED 3261 ia = ipv4_iffindaddr(ifp, &lease->addr, NULL); 3262 if (ia && ia->addr_flags & IN_IFF_DUPLICATED) { 3263 LOGDHCP(LOG_WARNING, "declined duplicate address"); 3264 if (type) 3265 dhcp_decline(ifp); 3266 ipv4_deladdr(ia, 0); 3267 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3268 eloop_timeout_add_sec(ifp->ctx->eloop, 3269 DHCP_RAND_MAX, dhcp_discover, ifp); 3270 return; 3271 } 3272 #endif 3273 3274 bootp_copied = false; 3275 if ((type == 0 || type == DHCP_OFFER) && state->state == DHS_DISCOVER) { 3276 lease->frominfo = 0; 3277 lease->addr.s_addr = bootp->yiaddr; 3278 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie)); 3279 if (type == 0 || 3280 get_option_addr(ifp->ctx, 3281 &lease->server, bootp, bootp_len, DHO_SERVERID) != 0) 3282 lease->server.s_addr = INADDR_ANY; 3283 3284 /* Test for rapid commit in the OFFER */ 3285 if (!(ifp->ctx->options & DHCPCD_TEST) && 3286 has_option_mask(ifo->requestmask, DHO_RAPIDCOMMIT) && 3287 get_option(ifp->ctx, bootp, bootp_len, 3288 DHO_RAPIDCOMMIT, NULL)) 3289 { 3290 state->state = DHS_REQUEST; 3291 goto rapidcommit; 3292 } 3293 3294 LOGDHCP(LOG_INFO, "offered"); 3295 if (state->offer_len < bootp_len) { 3296 free(state->offer); 3297 if ((state->offer = malloc(bootp_len)) == NULL) { 3298 logerr(__func__); 3299 state->offer_len = 0; 3300 return; 3301 } 3302 } 3303 state->offer_len = bootp_len; 3304 memcpy(state->offer, bootp, bootp_len); 3305 bootp_copied = true; 3306 if (ifp->ctx->options & DHCPCD_TEST) { 3307 free(state->old); 3308 state->old = state->new; 3309 state->old_len = state->new_len; 3310 state->new = state->offer; 3311 state->new_len = state->offer_len; 3312 state->offer = NULL; 3313 state->offer_len = 0; 3314 state->reason = "TEST"; 3315 script_runreason(ifp, state->reason); 3316 eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS); 3317 state->bpf->bpf_flags |= BPF_EOF; 3318 return; 3319 } 3320 eloop_timeout_delete(ifp->ctx->eloop, send_discover, ifp); 3321 /* We don't request BOOTP addresses */ 3322 if (type) { 3323 /* We used to ARP check here, but that seems to be in 3324 * violation of RFC2131 where it only describes 3325 * DECLINE after REQUEST. 3326 * It also seems that some MS DHCP servers actually 3327 * ignore DECLINE if no REQUEST, ie we decline a 3328 * DISCOVER. */ 3329 dhcp_request(ifp); 3330 return; 3331 } 3332 } 3333 3334 if (type) { 3335 if (type == DHCP_OFFER) { 3336 LOGDHCP(LOG_WARNING, "ignoring offer of"); 3337 return; 3338 } 3339 3340 /* We should only be dealing with acks */ 3341 if (type != DHCP_ACK) { 3342 LOGDHCP(LOG_ERR, "not ACK or OFFER"); 3343 return; 3344 } 3345 3346 if (state->state == DHS_DISCOVER) { 3347 /* We only allow ACK of rapid commit DISCOVER. */ 3348 if (has_option_mask(ifo->requestmask, 3349 DHO_RAPIDCOMMIT) && 3350 get_option(ifp->ctx, bootp, bootp_len, 3351 DHO_RAPIDCOMMIT, NULL)) 3352 state->state = DHS_REQUEST; 3353 else { 3354 LOGDHCP(LOG_DEBUG, "ignoring ack of"); 3355 return; 3356 } 3357 } 3358 3359 rapidcommit: 3360 if (!(ifo->options & DHCPCD_INFORM)) 3361 LOGDHCP(LOG_DEBUG, "acknowledged"); 3362 else 3363 ifo->options &= ~DHCPCD_STATIC; 3364 } 3365 3366 /* No NAK, so reset the backoff 3367 * We don't reset on an OFFER message because the server could 3368 * potentially NAK the REQUEST. */ 3369 state->nakoff = 0; 3370 3371 /* BOOTP could have already assigned this above. */ 3372 if (!bootp_copied) { 3373 if (state->offer_len < bootp_len) { 3374 free(state->offer); 3375 if ((state->offer = malloc(bootp_len)) == NULL) { 3376 logerr(__func__); 3377 state->offer_len = 0; 3378 return; 3379 } 3380 } 3381 state->offer_len = bootp_len; 3382 memcpy(state->offer, bootp, bootp_len); 3383 } 3384 3385 lease->frominfo = 0; 3386 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3387 3388 #if defined(ARP) || defined(KERNEL_RFC5227) 3389 dhcp_arp_bind(ifp); 3390 #else 3391 dhcp_bind(ifp); 3392 #endif 3393 } 3394 3395 static void * 3396 get_udp_data(void *packet, size_t *len) 3397 { 3398 const struct ip *ip = packet; 3399 size_t ip_hl = (size_t)ip->ip_hl * 4; 3400 char *p = packet; 3401 3402 p += ip_hl + sizeof(struct udphdr); 3403 *len = (size_t)ntohs(ip->ip_len) - sizeof(struct udphdr) - ip_hl; 3404 return p; 3405 } 3406 3407 static bool 3408 is_packet_udp_bootp(void *packet, size_t plen) 3409 { 3410 struct ip *ip = packet; 3411 size_t ip_hlen; 3412 struct udphdr udp; 3413 3414 if (plen < sizeof(*ip)) 3415 return false; 3416 3417 if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP) 3418 return false; 3419 3420 /* Sanity. */ 3421 if (ntohs(ip->ip_len) > plen) 3422 return false; 3423 3424 ip_hlen = (size_t)ip->ip_hl * 4; 3425 if (ip_hlen < sizeof(*ip)) 3426 return false; 3427 3428 /* Check we have a UDP header and BOOTP. */ 3429 if (ip_hlen + sizeof(udp) + offsetof(struct bootp, vend) > plen) 3430 return false; 3431 3432 /* Sanity. */ 3433 memcpy(&udp, (char *)ip + ip_hlen, sizeof(udp)); 3434 if (ntohs(udp.uh_ulen) < sizeof(udp)) 3435 return false; 3436 if (ip_hlen + ntohs(udp.uh_ulen) > plen) 3437 return false; 3438 3439 /* Check it's to and from the right ports. */ 3440 if (udp.uh_dport != htons(BOOTPC) || udp.uh_sport != htons(BOOTPS)) 3441 return false; 3442 3443 return true; 3444 } 3445 3446 /* Lengths have already been checked. */ 3447 static bool 3448 checksums_valid(void *packet, 3449 struct in_addr *from, unsigned int flags) 3450 { 3451 struct ip *ip = packet; 3452 union pip { 3453 struct ip ip; 3454 uint16_t w[sizeof(struct ip) / 2]; 3455 } pip = { 3456 .ip = { 3457 .ip_p = IPPROTO_UDP, 3458 .ip_src = ip->ip_src, 3459 .ip_dst = ip->ip_dst, 3460 } 3461 }; 3462 size_t ip_hlen; 3463 struct udphdr udp; 3464 char *udpp, *uh_sump; 3465 uint32_t csum; 3466 3467 if (from != NULL) 3468 from->s_addr = ip->ip_src.s_addr; 3469 3470 ip_hlen = (size_t)ip->ip_hl * 4; 3471 if (in_cksum(ip, ip_hlen, NULL) != 0) 3472 return false; 3473 3474 if (flags & BPF_PARTIALCSUM) 3475 return true; 3476 3477 udpp = (char *)ip + ip_hlen; 3478 memcpy(&udp, udpp, sizeof(udp)); 3479 if (udp.uh_sum == 0) 3480 return true; 3481 3482 /* UDP checksum is based on a pseudo IP header alongside 3483 * the UDP header and payload. */ 3484 pip.ip.ip_len = udp.uh_ulen; 3485 csum = 0; 3486 3487 /* Need to zero the UDP sum in the packet for the checksum to work. */ 3488 uh_sump = udpp + offsetof(struct udphdr, uh_sum); 3489 memset(uh_sump, 0, sizeof(udp.uh_sum)); 3490 3491 /* Checksum pseudo header and then UDP + payload. */ 3492 in_cksum(pip.w, sizeof(pip.w), &csum); 3493 csum = in_cksum(udpp, ntohs(udp.uh_ulen), &csum); 3494 3495 #if 0 /* Not needed, just here for completeness. */ 3496 /* Put the checksum back. */ 3497 memcpy(uh_sump, &udp.uh_sum, sizeof(udp.uh_sum)); 3498 #endif 3499 3500 return csum == udp.uh_sum; 3501 } 3502 3503 static void 3504 dhcp_handlebootp(struct interface *ifp, struct bootp *bootp, size_t len, 3505 struct in_addr *from) 3506 { 3507 size_t v; 3508 3509 if (len < offsetof(struct bootp, vend)) { 3510 logerrx("%s: truncated packet (%zu) from %s", 3511 ifp->name, len, inet_ntoa(*from)); 3512 return; 3513 } 3514 3515 /* Unlikely, but appeases sanitizers. */ 3516 if (len > FRAMELEN_MAX) { 3517 logerrx("%s: packet exceeded frame length (%zu) from %s", 3518 ifp->name, len, inet_ntoa(*from)); 3519 return; 3520 } 3521 3522 /* To make our IS_DHCP macro easy, ensure the vendor 3523 * area has at least 4 octets. */ 3524 v = len - offsetof(struct bootp, vend); 3525 while (v < 4) { 3526 bootp->vend[v++] = '\0'; 3527 len++; 3528 } 3529 3530 dhcp_handledhcp(ifp, bootp, len, from); 3531 } 3532 3533 void 3534 dhcp_packet(struct interface *ifp, uint8_t *data, size_t len, 3535 unsigned int bpf_flags) 3536 { 3537 struct bootp *bootp; 3538 struct in_addr from; 3539 size_t udp_len; 3540 size_t fl = bpf_frame_header_len(ifp); 3541 #ifdef PRIVSEP 3542 const struct dhcp_state *state = D_CSTATE(ifp); 3543 3544 /* It's possible that an interface departs and arrives in short 3545 * order to receive a BPF frame out of order. 3546 * There is a similar check in ARP, but much lower down the stack. 3547 * It's not needed for other inet protocols because we send the 3548 * message as a whole and select the interface off that and then 3549 * check state. BPF on the other hand is very interface 3550 * specific and we do need this check. */ 3551 if (state == NULL) 3552 return; 3553 3554 /* Ignore double reads */ 3555 if (IN_PRIVSEP(ifp->ctx)) { 3556 switch (state->state) { 3557 case DHS_BOUND: /* FALLTHROUGH */ 3558 case DHS_RENEW: 3559 return; 3560 default: 3561 break; 3562 } 3563 } 3564 #endif 3565 3566 /* Trim frame header */ 3567 if (fl != 0) { 3568 if (len < fl) { 3569 logerrx("%s: %s: short frame header %zu", 3570 __func__, ifp->name, len); 3571 return; 3572 } 3573 len -= fl; 3574 /* Move the data to avoid alignment errors. */ 3575 memmove(data, data + fl, len); 3576 } 3577 3578 /* Validate filter. */ 3579 if (!is_packet_udp_bootp(data, len)) { 3580 #ifdef BPF_DEBUG 3581 logerrx("%s: DHCP BPF validation failure", ifp->name); 3582 #endif 3583 return; 3584 } 3585 3586 if (!checksums_valid(data, &from, bpf_flags)) { 3587 logerrx("%s: checksum failure from %s", 3588 ifp->name, inet_ntoa(from)); 3589 return; 3590 } 3591 3592 /* 3593 * DHCP has a variable option area rather than a fixed vendor area. 3594 * Because DHCP uses the BOOTP protocol it should still send BOOTP 3595 * sized packets to be RFC compliant. 3596 * However some servers send a truncated vendor area. 3597 * dhcpcd can work fine without the vendor area being sent. 3598 */ 3599 bootp = get_udp_data(data, &udp_len); 3600 dhcp_handlebootp(ifp, bootp, udp_len, &from); 3601 } 3602 3603 static void 3604 dhcp_readbpf(void *arg, unsigned short events) 3605 { 3606 struct interface *ifp = arg; 3607 uint8_t buf[FRAMELEN_MAX]; 3608 ssize_t bytes; 3609 struct dhcp_state *state = D_STATE(ifp); 3610 struct bpf *bpf = state->bpf; 3611 3612 if (events != ELE_READ) 3613 logerrx("%s: unexpected event 0x%04x", __func__, events); 3614 3615 bpf->bpf_flags &= ~BPF_EOF; 3616 while (!(bpf->bpf_flags & BPF_EOF)) { 3617 bytes = bpf_read(bpf, buf, sizeof(buf)); 3618 if (bytes == -1) { 3619 if (state->state != DHS_NONE) { 3620 logerr("%s: %s", __func__, ifp->name); 3621 dhcp_close(ifp); 3622 } 3623 break; 3624 } 3625 dhcp_packet(ifp, buf, (size_t)bytes, bpf->bpf_flags); 3626 /* Check we still have a state after processing. */ 3627 if ((state = D_STATE(ifp)) == NULL) 3628 break; 3629 if ((bpf = state->bpf) == NULL) 3630 break; 3631 } 3632 } 3633 3634 void 3635 dhcp_recvmsg(struct dhcpcd_ctx *ctx, struct msghdr *msg) 3636 { 3637 struct sockaddr_in *from = (struct sockaddr_in *)msg->msg_name; 3638 struct iovec *iov = &msg->msg_iov[0]; 3639 struct interface *ifp; 3640 const struct dhcp_state *state; 3641 3642 ifp = if_findifpfromcmsg(ctx, msg, NULL); 3643 if (ifp == NULL) { 3644 logerr(__func__); 3645 return; 3646 } 3647 state = D_CSTATE(ifp); 3648 if (state == NULL) { 3649 /* Try re-directing it to another interface. */ 3650 dhcp_redirect_dhcp(ifp, (struct bootp *)iov->iov_base, 3651 iov->iov_len, &from->sin_addr); 3652 return; 3653 } 3654 3655 if (state->bpf != NULL) { 3656 /* Avoid a duplicate read if BPF is open for the interface. */ 3657 return; 3658 } 3659 #ifdef PRIVSEP 3660 if (IN_PRIVSEP(ctx)) { 3661 switch (state->state) { 3662 case DHS_BOUND: /* FALLTHROUGH */ 3663 case DHS_RENEW: 3664 break; 3665 default: 3666 /* Any other state we ignore it or will receive 3667 * via BPF. */ 3668 return; 3669 } 3670 } 3671 #endif 3672 3673 dhcp_handlebootp(ifp, iov->iov_base, iov->iov_len, 3674 &from->sin_addr); 3675 } 3676 3677 static void 3678 dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp, 3679 unsigned short events) 3680 { 3681 const struct dhcp_state *state; 3682 struct sockaddr_in from; 3683 union { 3684 struct bootp bootp; 3685 uint8_t buf[10 * 1024]; /* Maximum MTU */ 3686 } iovbuf; 3687 struct iovec iov = { 3688 .iov_base = iovbuf.buf, 3689 .iov_len = sizeof(iovbuf.buf), 3690 }; 3691 union { 3692 struct cmsghdr hdr; 3693 #ifdef IP_RECVIF 3694 uint8_t buf[CMSG_SPACE(sizeof(struct sockaddr_dl))]; 3695 #else 3696 uint8_t buf[CMSG_SPACE(sizeof(struct in_pktinfo))]; 3697 #endif 3698 } cmsgbuf = { .buf = { 0 } }; 3699 struct msghdr msg = { 3700 .msg_name = &from, .msg_namelen = sizeof(from), 3701 .msg_iov = &iov, .msg_iovlen = 1, 3702 .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf), 3703 }; 3704 int s; 3705 ssize_t bytes; 3706 3707 if (events != ELE_READ) 3708 logerrx("%s: unexpected event 0x%04x", __func__, events); 3709 3710 if (ifp != NULL) { 3711 state = D_CSTATE(ifp); 3712 s = state->udp_rfd; 3713 } else 3714 s = ctx->udp_rfd; 3715 3716 bytes = recvmsg(s, &msg, 0); 3717 if (bytes == -1) { 3718 logerr(__func__); 3719 return; 3720 } 3721 3722 iov.iov_len = (size_t)bytes; 3723 dhcp_recvmsg(ctx, &msg); 3724 } 3725 3726 static void 3727 dhcp_handleudp(void *arg, unsigned short events) 3728 { 3729 struct dhcpcd_ctx *ctx = arg; 3730 3731 dhcp_readudp(ctx, NULL, events); 3732 } 3733 3734 static void 3735 dhcp_handleifudp(void *arg, unsigned short events) 3736 { 3737 struct interface *ifp = arg; 3738 3739 dhcp_readudp(ifp->ctx, ifp, events); 3740 } 3741 3742 static int 3743 dhcp_openbpf(struct interface *ifp) 3744 { 3745 struct dhcp_state *state; 3746 3747 state = D_STATE(ifp); 3748 3749 #ifdef PRIVSEP 3750 if (IN_PRIVSEP_SE(ifp->ctx)) { 3751 if (ps_bpf_openbootp(ifp) == -1) { 3752 logerr(__func__); 3753 return -1; 3754 } 3755 return 0; 3756 } 3757 #endif 3758 3759 if (state->bpf != NULL) 3760 return 0; 3761 3762 state->bpf = bpf_open(ifp, bpf_bootp, NULL); 3763 if (state->bpf == NULL) { 3764 if (errno == ENOENT) { 3765 logerrx("%s not found", bpf_name); 3766 /* May as well disable IPv4 entirely at 3767 * this point as we really need it. */ 3768 ifp->options->options &= ~DHCPCD_IPV4; 3769 } else 3770 logerr("%s: %s", __func__, ifp->name); 3771 return -1; 3772 } 3773 3774 if (eloop_event_add(ifp->ctx->eloop, state->bpf->bpf_fd, ELE_READ, 3775 dhcp_readbpf, ifp) == -1) 3776 logerr("%s: eloop_event_add", __func__); 3777 return 0; 3778 } 3779 3780 void 3781 dhcp_free(struct interface *ifp) 3782 { 3783 struct dhcp_state *state = D_STATE(ifp); 3784 struct dhcpcd_ctx *ctx; 3785 3786 dhcp_close(ifp); 3787 #ifdef ARP 3788 arp_drop(ifp); 3789 #endif 3790 if (state) { 3791 state->state = DHS_NONE; 3792 free(state->old); 3793 free(state->new); 3794 free(state->offer); 3795 free(state->clientid); 3796 free(state); 3797 } 3798 3799 ctx = ifp->ctx; 3800 /* If we don't have any more DHCP enabled interfaces, 3801 * close the global socket and release resources */ 3802 if (ctx->ifaces) { 3803 TAILQ_FOREACH(ifp, ctx->ifaces, next) { 3804 state = D_STATE(ifp); 3805 if (state != NULL && state->state != DHS_NONE) 3806 break; 3807 } 3808 } 3809 if (ifp == NULL) { 3810 if (ctx->udp_rfd != -1) { 3811 eloop_event_delete(ctx->eloop, ctx->udp_rfd); 3812 close(ctx->udp_rfd); 3813 ctx->udp_rfd = -1; 3814 } 3815 if (ctx->udp_wfd != -1) { 3816 close(ctx->udp_wfd); 3817 ctx->udp_wfd = -1; 3818 } 3819 3820 free(ctx->opt_buffer); 3821 ctx->opt_buffer = NULL; 3822 ctx->opt_buffer_len = 0; 3823 } 3824 } 3825 3826 static int 3827 dhcp_initstate(struct interface *ifp) 3828 { 3829 struct dhcp_state *state; 3830 3831 state = D_STATE(ifp); 3832 if (state != NULL) 3833 return 0; 3834 3835 ifp->if_data[IF_DATA_DHCP] = calloc(1, sizeof(*state)); 3836 state = D_STATE(ifp); 3837 if (state == NULL) 3838 return -1; 3839 3840 state->state = DHS_NONE; 3841 /* 0 is a valid fd, so init to -1 */ 3842 state->udp_rfd = -1; 3843 #ifdef ARPING 3844 state->arping_index = -1; 3845 #endif 3846 return 1; 3847 } 3848 3849 static int 3850 dhcp_init(struct interface *ifp) 3851 { 3852 struct dhcp_state *state; 3853 struct if_options *ifo; 3854 uint8_t len; 3855 char buf[(sizeof(ifo->clientid) - 1) * 3]; 3856 3857 if (dhcp_initstate(ifp) == -1) 3858 return -1; 3859 3860 state = D_STATE(ifp); 3861 state->state = DHS_INIT; 3862 state->reason = "PREINIT"; 3863 state->nakoff = 0; 3864 dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile), 3865 AF_INET, ifp); 3866 3867 ifo = ifp->options; 3868 /* We need to drop the leasefile so that dhcp_start 3869 * doesn't load it. */ 3870 if (ifo->options & DHCPCD_REQUEST) 3871 dhcp_unlink(ifp->ctx, state->leasefile); 3872 3873 free(state->clientid); 3874 state->clientid = NULL; 3875 3876 if (ifo->options & DHCPCD_ANONYMOUS) { 3877 /* Removing the option could show that we want anonymous. 3878 * As such keep it as it's already in the hwaddr field. */ 3879 goto make_clientid; 3880 } else if (*ifo->clientid) { 3881 state->clientid = malloc((size_t)(ifo->clientid[0] + 1)); 3882 if (state->clientid == NULL) 3883 goto eexit; 3884 memcpy(state->clientid, ifo->clientid, 3885 (size_t)(ifo->clientid[0]) + 1); 3886 } else if (ifo->options & DHCPCD_CLIENTID) { 3887 if (ifo->options & DHCPCD_DUID) { 3888 state->clientid = malloc(ifp->ctx->duid_len + 6); 3889 if (state->clientid == NULL) 3890 goto eexit; 3891 state->clientid[0] =(uint8_t)(ifp->ctx->duid_len + 5); 3892 state->clientid[1] = 255; /* RFC 4361 */ 3893 memcpy(state->clientid + 2, ifo->iaid, 4); 3894 memcpy(state->clientid + 6, ifp->ctx->duid, 3895 ifp->ctx->duid_len); 3896 } else { 3897 make_clientid: 3898 len = (uint8_t)(ifp->hwlen + 1); 3899 state->clientid = malloc((size_t)len + 1); 3900 if (state->clientid == NULL) 3901 goto eexit; 3902 state->clientid[0] = len; 3903 state->clientid[1] = (uint8_t)ifp->hwtype; 3904 memcpy(state->clientid + 2, ifp->hwaddr, 3905 ifp->hwlen); 3906 } 3907 } 3908 3909 if (ifo->options & DHCPCD_DUID) 3910 /* Don't bother logging as DUID and IAID are reported 3911 * at device start. */ 3912 return 0; 3913 3914 if (ifo->options & DHCPCD_CLIENTID && state->clientid != NULL) 3915 logdebugx("%s: using ClientID %s", ifp->name, 3916 hwaddr_ntoa(state->clientid + 1, state->clientid[0], 3917 buf, sizeof(buf))); 3918 else if (ifp->hwlen) 3919 logdebugx("%s: using hwaddr %s", ifp->name, 3920 hwaddr_ntoa(ifp->hwaddr, ifp->hwlen, buf, sizeof(buf))); 3921 return 0; 3922 3923 eexit: 3924 logerr(__func__); 3925 return -1; 3926 } 3927 3928 static void 3929 dhcp_start1(void *arg) 3930 { 3931 struct interface *ifp = arg; 3932 struct dhcpcd_ctx *ctx = ifp->ctx; 3933 struct if_options *ifo = ifp->options; 3934 struct dhcp_state *state; 3935 uint32_t l; 3936 int nolease; 3937 3938 if (!(ifo->options & DHCPCD_IPV4)) 3939 return; 3940 3941 /* Listen on *.*.*.*:bootpc so that the kernel never sends an 3942 * ICMP port unreachable message back to the DHCP server. 3943 * Only do this in manager mode so we don't swallow messages 3944 * for dhcpcd running on another interface. */ 3945 if ((ctx->options & (DHCPCD_MANAGER|DHCPCD_PRIVSEP)) == DHCPCD_MANAGER 3946 && ctx->udp_rfd == -1) 3947 { 3948 ctx->udp_rfd = dhcp_openudp(NULL); 3949 if (ctx->udp_rfd == -1) { 3950 logerr(__func__); 3951 return; 3952 } 3953 if (eloop_event_add(ctx->eloop, ctx->udp_rfd, ELE_READ, 3954 dhcp_handleudp, ctx) == -1) 3955 logerr("%s: eloop_event_add", __func__); 3956 } 3957 if (!IN_PRIVSEP(ctx) && ctx->udp_wfd == -1) { 3958 ctx->udp_wfd = xsocket(PF_INET, SOCK_RAW|SOCK_CXNB,IPPROTO_UDP); 3959 if (ctx->udp_wfd == -1) { 3960 logerr(__func__); 3961 return; 3962 } 3963 } 3964 3965 if (dhcp_init(ifp) == -1) { 3966 logerr("%s: dhcp_init", ifp->name); 3967 return; 3968 } 3969 3970 state = D_STATE(ifp); 3971 clock_gettime(CLOCK_MONOTONIC, &state->started); 3972 state->interval = 0; 3973 free(state->offer); 3974 state->offer = NULL; 3975 state->offer_len = 0; 3976 3977 #ifdef ARPING 3978 if (ifo->arping_len && state->arping_index < ifo->arping_len) { 3979 dhcp_arping(ifp); 3980 return; 3981 } 3982 #endif 3983 3984 if (ifo->options & DHCPCD_STATIC) { 3985 dhcp_static(ifp); 3986 return; 3987 } 3988 3989 if (ifo->options & DHCPCD_INFORM) { 3990 dhcp_inform(ifp); 3991 return; 3992 } 3993 3994 /* We don't want to read the old lease if we NAK an old test */ 3995 nolease = state->offer && ifp->ctx->options & DHCPCD_TEST; 3996 if (!nolease && ifo->options & DHCPCD_DHCP) { 3997 state->offer_len = read_lease(ifp, &state->offer); 3998 /* Check the saved lease matches the type we want */ 3999 if (state->offer) { 4000 #ifdef IN_IFF_DUPLICATED 4001 struct in_addr addr; 4002 struct ipv4_addr *ia; 4003 4004 addr.s_addr = state->offer->yiaddr; 4005 ia = ipv4_iffindaddr(ifp, &addr, NULL); 4006 #endif 4007 4008 if ((!IS_DHCP(state->offer) && 4009 !(ifo->options & DHCPCD_BOOTP)) || 4010 #ifdef IN_IFF_DUPLICATED 4011 (ia && ia->addr_flags & IN_IFF_DUPLICATED) || 4012 #endif 4013 (IS_DHCP(state->offer) && 4014 ifo->options & DHCPCD_BOOTP)) 4015 { 4016 free(state->offer); 4017 state->offer = NULL; 4018 state->offer_len = 0; 4019 } 4020 } 4021 } 4022 if (state->offer) { 4023 struct ipv4_addr *ia; 4024 time_t mtime; 4025 4026 get_lease(ifp, &state->lease, state->offer, state->offer_len); 4027 state->lease.frominfo = 1; 4028 if (state->new == NULL && 4029 (ia = ipv4_iffindaddr(ifp, 4030 &state->lease.addr, &state->lease.mask)) != NULL) 4031 { 4032 /* We still have the IP address from the last lease. 4033 * Fake add the address and routes from it so the lease 4034 * can be cleaned up. */ 4035 state->new = malloc(state->offer_len); 4036 if (state->new) { 4037 memcpy(state->new, 4038 state->offer, state->offer_len); 4039 state->new_len = state->offer_len; 4040 state->addr = ia; 4041 state->added |= STATE_ADDED | STATE_FAKE; 4042 rt_build(ifp->ctx, AF_INET); 4043 } else 4044 logerr(__func__); 4045 } 4046 if (!IS_DHCP(state->offer)) { 4047 free(state->offer); 4048 state->offer = NULL; 4049 state->offer_len = 0; 4050 } else if (!(ifo->options & DHCPCD_LASTLEASE_EXTEND) && 4051 state->lease.leasetime != DHCP_INFINITE_LIFETIME && 4052 dhcp_filemtime(ifp->ctx, state->leasefile, &mtime) == 0) 4053 { 4054 time_t now; 4055 4056 /* Offset lease times and check expiry */ 4057 now = time(NULL); 4058 if (now == -1 || 4059 (time_t)state->lease.leasetime < now - mtime) 4060 { 4061 logdebugx("%s: discarding expired lease", 4062 ifp->name); 4063 free(state->offer); 4064 state->offer = NULL; 4065 state->offer_len = 0; 4066 state->lease.addr.s_addr = 0; 4067 /* Technically we should discard the lease 4068 * as it's expired, just as DHCPv6 addresses 4069 * would be by the kernel. 4070 * However, this may violate POLA so 4071 * we currently leave it be. 4072 * If we get a totally different lease from 4073 * the DHCP server we'll drop it anyway, as 4074 * we will on any other event which would 4075 * trigger a lease drop. 4076 * This should only happen if dhcpcd stops 4077 * running and the lease expires before 4078 * dhcpcd starts again. */ 4079 #if 0 4080 if (state->new) 4081 dhcp_drop(ifp, "EXPIRE"); 4082 #endif 4083 } else { 4084 l = (uint32_t)(now - mtime); 4085 state->lease.leasetime -= l; 4086 state->lease.renewaltime -= l; 4087 state->lease.rebindtime -= l; 4088 } 4089 } 4090 } 4091 4092 #ifdef IPV4LL 4093 if (!(ifo->options & DHCPCD_DHCP)) { 4094 if (ifo->options & DHCPCD_IPV4LL) 4095 ipv4ll_start(ifp); 4096 return; 4097 } 4098 #endif 4099 4100 if (state->offer == NULL || 4101 !IS_DHCP(state->offer) || 4102 ifo->options & DHCPCD_ANONYMOUS) 4103 dhcp_discover(ifp); 4104 else 4105 dhcp_reboot(ifp); 4106 } 4107 4108 void 4109 dhcp_start(struct interface *ifp) 4110 { 4111 unsigned int delay; 4112 #ifdef ARPING 4113 const struct dhcp_state *state; 4114 #endif 4115 4116 if (!(ifp->options->options & DHCPCD_IPV4)) 4117 return; 4118 4119 /* If we haven't been given a netmask for our requested address, 4120 * set it now. */ 4121 if (ifp->options->req_addr.s_addr != INADDR_ANY && 4122 ifp->options->req_mask.s_addr == INADDR_ANY) 4123 ifp->options->req_mask.s_addr = 4124 ipv4_getnetmask(ifp->options->req_addr.s_addr); 4125 4126 /* If we haven't specified a ClientID and our hardware address 4127 * length is greater than BOOTP CHADDR then we enforce a ClientID 4128 * of the hardware address type and the hardware address. 4129 * If there is no hardware address and no ClientID set, 4130 * force a DUID based ClientID. */ 4131 if (ifp->hwlen > 16) 4132 ifp->options->options |= DHCPCD_CLIENTID; 4133 else if (ifp->hwlen == 0 && !(ifp->options->options & DHCPCD_CLIENTID)) 4134 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_DUID; 4135 4136 /* Firewire and InfiniBand interfaces require ClientID and 4137 * the broadcast option being set. */ 4138 switch (ifp->hwtype) { 4139 case ARPHRD_IEEE1394: /* FALLTHROUGH */ 4140 case ARPHRD_INFINIBAND: 4141 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_BROADCAST; 4142 break; 4143 } 4144 4145 /* If we violate RFC2131 section 3.7 then require ARP 4146 * to detect if any other client wants our address. */ 4147 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) 4148 ifp->options->options |= DHCPCD_ARP; 4149 4150 /* No point in delaying a static configuration */ 4151 if (ifp->options->options & DHCPCD_STATIC || 4152 !(ifp->options->options & DHCPCD_INITIAL_DELAY)) 4153 { 4154 dhcp_start1(ifp); 4155 return; 4156 } 4157 4158 #ifdef ARPING 4159 /* If we have arpinged then we have already delayed. */ 4160 state = D_CSTATE(ifp); 4161 if (state != NULL && state->arping_index != -1) { 4162 dhcp_start1(ifp); 4163 return; 4164 } 4165 #endif 4166 delay = MSEC_PER_SEC + 4167 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC); 4168 logdebugx("%s: delaying IPv4 for %0.1f seconds", 4169 ifp->name, (float)delay / MSEC_PER_SEC); 4170 4171 eloop_timeout_add_msec(ifp->ctx->eloop, delay, dhcp_start1, ifp); 4172 } 4173 4174 void 4175 dhcp_abort(struct interface *ifp) 4176 { 4177 struct dhcp_state *state; 4178 4179 state = D_STATE(ifp); 4180 #ifdef ARPING 4181 if (state != NULL) 4182 state->arping_index = -1; 4183 #endif 4184 4185 eloop_timeout_delete(ifp->ctx->eloop, dhcp_start1, ifp); 4186 4187 if (state != NULL && state->added) { 4188 rt_build(ifp->ctx, AF_INET); 4189 #ifdef ARP 4190 if (ifp->options->options & DHCPCD_ARP) 4191 arp_announceaddr(ifp->ctx, &state->addr->addr); 4192 #endif 4193 } 4194 } 4195 4196 struct ipv4_addr * 4197 dhcp_handleifa(int cmd, struct ipv4_addr *ia, pid_t pid) 4198 { 4199 struct interface *ifp; 4200 struct dhcp_state *state; 4201 struct if_options *ifo; 4202 uint8_t i; 4203 4204 ifp = ia->iface; 4205 state = D_STATE(ifp); 4206 if (state == NULL || state->state == DHS_NONE) 4207 return ia; 4208 4209 if (cmd == RTM_DELADDR) { 4210 if (state->addr == ia) { 4211 loginfox("%s: pid %d deleted IP address %s", 4212 ifp->name, pid, ia->saddr); 4213 dhcp_close(ifp); 4214 state->addr = NULL; 4215 /* Don't clear the added state as we need 4216 * to drop the lease. */ 4217 dhcp_drop(ifp, "EXPIRE"); 4218 dhcp_start1(ifp); 4219 return ia; 4220 } 4221 } 4222 4223 if (cmd != RTM_NEWADDR) 4224 return ia; 4225 4226 #ifdef IN_IFF_NOTUSEABLE 4227 if (!(ia->addr_flags & IN_IFF_NOTUSEABLE)) 4228 dhcp_finish_dad(ifp, &ia->addr); 4229 else if (ia->addr_flags & IN_IFF_DUPLICATED) 4230 return dhcp_addr_duplicated(ifp, &ia->addr) ? NULL : ia; 4231 #endif 4232 4233 ifo = ifp->options; 4234 4235 #ifdef PRIVSEP 4236 if (IN_PRIVSEP_SE(ifp->ctx) && 4237 !(ifp->ctx->options & (DHCPCD_MANAGER | DHCPCD_CONFIGURE)) && 4238 IN_ARE_ADDR_EQUAL(&state->lease.addr, &ia->addr)) 4239 { 4240 state->addr = ia; 4241 state->added = STATE_ADDED; 4242 dhcp_closebpf(ifp); 4243 if (ps_inet_openbootp(ia) == -1) 4244 logerr(__func__); 4245 } 4246 #endif 4247 4248 /* If we have requested a specific address, return now. 4249 * The below code is only for when inform or static has been 4250 * requested without a specific address. */ 4251 if (ifo->req_addr.s_addr != INADDR_ANY) 4252 return ia; 4253 4254 /* Only inform if we are NOT in the inform state or bound. */ 4255 if (ifo->options & DHCPCD_INFORM) { 4256 if (state->state != DHS_INFORM && state->state != DHS_BOUND) 4257 dhcp_inform(ifp); 4258 return ia; 4259 } 4260 4261 /* Static and inform are mutually exclusive. If not static, return. */ 4262 if (!(ifo->options & DHCPCD_STATIC)) 4263 return ia; 4264 4265 free(state->old); 4266 state->old = state->new; 4267 state->new_len = dhcp_message_new(&state->new, &ia->addr, &ia->mask); 4268 if (state->new == NULL) 4269 return ia; 4270 4271 if (ifp->flags & IFF_POINTOPOINT) { 4272 for (i = 1; i < 255; i++) 4273 if (i != DHO_ROUTER && has_option_mask(ifo->dstmask,i)) 4274 dhcp_message_add_addr(state->new, i, ia->brd); 4275 } 4276 4277 state->reason = "STATIC"; 4278 rt_build(ifp->ctx, AF_INET); 4279 script_runreason(ifp, state->reason); 4280 4281 return ia; 4282 } 4283 4284 #ifndef SMALL 4285 int 4286 dhcp_dump(struct interface *ifp) 4287 { 4288 struct dhcp_state *state; 4289 4290 ifp->if_data[IF_DATA_DHCP] = state = calloc(1, sizeof(*state)); 4291 if (state == NULL) { 4292 logerr(__func__); 4293 return -1; 4294 } 4295 state->new_len = read_lease(ifp, &state->new); 4296 if (state->new == NULL) { 4297 logerr("read_lease"); 4298 return -1; 4299 } 4300 state->reason = "DUMP"; 4301 return script_runreason(ifp, state->reason); 4302 } 4303 #endif 4304