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_requestfailed(void *arg) 1900 { 1901 struct interface *ifp = arg; 1902 struct dhcp_state *state = D_STATE(ifp); 1903 1904 logwarnx("%s: failed to request the lease", ifp->name); 1905 free(state->offer); 1906 state->offer = NULL; 1907 state->offer_len = 0; 1908 state->interval = 0; 1909 dhcp_discover(ifp); 1910 } 1911 1912 static void 1913 dhcp_request(void *arg) 1914 { 1915 struct interface *ifp = arg; 1916 struct dhcp_state *state = D_STATE(ifp); 1917 1918 state->state = DHS_REQUEST; 1919 // Handle the server being silent to our request. 1920 eloop_timeout_add_sec(ifp->ctx->eloop, ifp->options->reboot, 1921 dhcp_requestfailed, ifp); 1922 send_request(ifp); 1923 } 1924 1925 static void 1926 dhcp_expire(void *arg) 1927 { 1928 struct interface *ifp = arg; 1929 struct dhcp_state *state = D_STATE(ifp); 1930 1931 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) { 1932 logwarnx("%s: DHCP lease expired, extending lease", ifp->name); 1933 state->added |= STATE_EXPIRED; 1934 } else { 1935 logerrx("%s: DHCP lease expired", ifp->name); 1936 dhcp_drop(ifp, "EXPIRE"); 1937 dhcp_unlink(ifp->ctx, state->leasefile); 1938 } 1939 state->interval = 0; 1940 dhcp_discover(ifp); 1941 } 1942 1943 #if defined(ARP) || defined(IN_IFF_DUPLICATED) 1944 static void 1945 dhcp_decline(struct interface *ifp) 1946 { 1947 1948 send_message(ifp, DHCP_DECLINE, NULL); 1949 } 1950 #endif 1951 1952 static void 1953 dhcp_startrenew(void *arg) 1954 { 1955 struct interface *ifp = arg; 1956 struct dhcp_state *state; 1957 struct dhcp_lease *lease; 1958 1959 if ((state = D_STATE(ifp)) == NULL) 1960 return; 1961 1962 /* Only renew in the bound or renew states */ 1963 if (state->state != DHS_BOUND && 1964 state->state != DHS_RENEW) 1965 return; 1966 1967 /* Remove the timeout as the renew may have been forced. */ 1968 eloop_timeout_delete(ifp->ctx->eloop, dhcp_startrenew, ifp); 1969 1970 lease = &state->lease; 1971 logdebugx("%s: renewing lease of %s", ifp->name, 1972 inet_ntoa(lease->addr)); 1973 state->state = DHS_RENEW; 1974 dhcp_new_xid(ifp); 1975 state->interval = 0; 1976 send_renew(ifp); 1977 } 1978 1979 void 1980 dhcp_renew(struct interface *ifp) 1981 { 1982 1983 dhcp_startrenew(ifp); 1984 } 1985 1986 static void 1987 dhcp_rebind(void *arg) 1988 { 1989 struct interface *ifp = arg; 1990 struct dhcp_state *state = D_STATE(ifp); 1991 struct dhcp_lease *lease = &state->lease; 1992 1993 logwarnx("%s: failed to renew DHCP, rebinding", ifp->name); 1994 logdebugx("%s: expire in %"PRIu32" seconds", 1995 ifp->name, lease->leasetime - lease->rebindtime); 1996 state->state = DHS_REBIND; 1997 eloop_timeout_delete(ifp->ctx->eloop, send_renew, ifp); 1998 state->lease.server.s_addr = INADDR_ANY; 1999 state->interval = 0; 2000 ifp->options->options &= ~(DHCPCD_CSR_WARNED | 2001 DHCPCD_ROUTER_HOST_ROUTE_WARNED); 2002 send_rebind(ifp); 2003 } 2004 2005 #if defined(ARP) || defined(IN_IFF_DUPLICATED) 2006 static void 2007 dhcp_finish_dad(struct interface *ifp, struct in_addr *ia) 2008 { 2009 struct dhcp_state *state = D_STATE(ifp); 2010 2011 if (state->state == DHS_BOUND) 2012 return; 2013 if (state->offer == NULL || state->offer->yiaddr != ia->s_addr) 2014 return; 2015 2016 logdebugx("%s: DAD completed for %s", ifp->name, inet_ntoa(*ia)); 2017 if (!(ifp->options->options & DHCPCD_INFORM)) 2018 dhcp_bind(ifp); 2019 #ifndef IN_IFF_DUPLICATED 2020 else { 2021 struct bootp *bootp; 2022 size_t len; 2023 2024 bootp = state->new; 2025 len = state->new_len; 2026 state->new = state->offer; 2027 state->new_len = state->offer_len; 2028 get_lease(ifp, &state->lease, state->new, state->new_len); 2029 ipv4_applyaddr(ifp); 2030 state->new = bootp; 2031 state->new_len = len; 2032 } 2033 #endif 2034 2035 #ifdef IPV4LL 2036 /* Stop IPv4LL now we have a working DHCP address */ 2037 if (!IN_LINKLOCAL(ntohl(ia->s_addr))) 2038 ipv4ll_drop(ifp); 2039 #endif 2040 2041 if (ifp->options->options & DHCPCD_INFORM) 2042 dhcp_inform(ifp); 2043 } 2044 2045 static bool 2046 dhcp_addr_duplicated(struct interface *ifp, struct in_addr *ia) 2047 { 2048 struct dhcp_state *state = D_STATE(ifp); 2049 unsigned long long opts = ifp->options->options; 2050 struct dhcpcd_ctx *ctx = ifp->ctx; 2051 bool deleted = false; 2052 #ifdef IN_IFF_DUPLICATED 2053 struct ipv4_addr *iap; 2054 #endif 2055 2056 if ((state->offer == NULL || state->offer->yiaddr != ia->s_addr) && 2057 !IN_ARE_ADDR_EQUAL(ia, &state->lease.addr)) 2058 return deleted; 2059 2060 /* RFC 2131 3.1.5, Client-server interaction */ 2061 logerrx("%s: DAD detected %s", ifp->name, inet_ntoa(*ia)); 2062 dhcp_unlink(ifp->ctx, state->leasefile); 2063 if (!(opts & DHCPCD_STATIC) && !state->lease.frominfo) 2064 dhcp_decline(ifp); 2065 #ifdef IN_IFF_DUPLICATED 2066 if ((iap = ipv4_iffindaddr(ifp, ia, NULL)) != NULL) { 2067 ipv4_deladdr(iap, 0); 2068 deleted = true; 2069 } 2070 #endif 2071 eloop_timeout_delete(ctx->eloop, NULL, ifp); 2072 if (opts & (DHCPCD_STATIC | DHCPCD_INFORM)) { 2073 state->reason = "EXPIRE"; 2074 script_runreason(ifp, state->reason); 2075 #define NOT_ONLY_SELF (DHCPCD_MANAGER | DHCPCD_IPV6RS | DHCPCD_DHCP6) 2076 if (!(ctx->options & NOT_ONLY_SELF)) 2077 eloop_exit(ifp->ctx->eloop, EXIT_FAILURE); 2078 return deleted; 2079 } 2080 eloop_timeout_add_sec(ifp->ctx->eloop, 2081 DHCP_RAND_MAX, dhcp_discover, ifp); 2082 return deleted; 2083 } 2084 #endif 2085 2086 #ifdef ARP 2087 #ifdef KERNEL_RFC5227 2088 #ifdef ARPING 2089 static void 2090 dhcp_arp_announced(struct arp_state *state) 2091 { 2092 2093 arp_free(state); 2094 } 2095 #endif 2096 #else 2097 static void 2098 dhcp_arp_defend_failed(struct arp_state *astate) 2099 { 2100 struct interface *ifp = astate->iface; 2101 2102 dhcp_drop(ifp, "EXPIRED"); 2103 dhcp_start1(ifp); 2104 } 2105 #endif 2106 2107 #if !defined(KERNEL_RFC5227) || defined(ARPING) 2108 static void dhcp_arp_not_found(struct arp_state *); 2109 2110 static struct arp_state * 2111 dhcp_arp_new(struct interface *ifp, struct in_addr *addr) 2112 { 2113 struct arp_state *astate; 2114 2115 astate = arp_new(ifp, addr); 2116 if (astate == NULL) 2117 return NULL; 2118 2119 astate->found_cb = dhcp_arp_found; 2120 astate->not_found_cb = dhcp_arp_not_found; 2121 #ifdef KERNEL_RFC5227 2122 astate->announced_cb = dhcp_arp_announced; 2123 #else 2124 astate->announced_cb = NULL; 2125 astate->defend_failed_cb = dhcp_arp_defend_failed; 2126 #endif 2127 return astate; 2128 } 2129 #endif 2130 2131 #ifdef ARPING 2132 static int 2133 dhcp_arping(struct interface *ifp) 2134 { 2135 struct dhcp_state *state; 2136 struct if_options *ifo; 2137 struct arp_state *astate; 2138 struct in_addr addr; 2139 2140 state = D_STATE(ifp); 2141 ifo = ifp->options; 2142 2143 if (ifo->arping_len == 0 || state->arping_index > ifo->arping_len) 2144 return 0; 2145 2146 if (state->arping_index + 1 == ifo->arping_len) { 2147 state->arping_index++; 2148 dhcpcd_startinterface(ifp); 2149 return 1; 2150 } 2151 2152 addr.s_addr = ifo->arping[++state->arping_index]; 2153 astate = dhcp_arp_new(ifp, &addr); 2154 if (astate == NULL) { 2155 logerr(__func__); 2156 return -1; 2157 } 2158 arp_probe(astate); 2159 return 1; 2160 } 2161 #endif 2162 2163 #if !defined(KERNEL_RFC5227) || defined(ARPING) 2164 static void 2165 dhcp_arp_not_found(struct arp_state *astate) 2166 { 2167 struct interface *ifp; 2168 2169 ifp = astate->iface; 2170 #ifdef ARPING 2171 if (dhcp_arping(ifp) == 1) { 2172 arp_free(astate); 2173 return; 2174 } 2175 #endif 2176 2177 dhcp_finish_dad(ifp, &astate->addr); 2178 } 2179 2180 static void 2181 dhcp_arp_found(struct arp_state *astate, const struct arp_msg *amsg) 2182 { 2183 struct in_addr addr; 2184 struct interface *ifp = astate->iface; 2185 #ifdef ARPING 2186 struct dhcp_state *state; 2187 struct if_options *ifo; 2188 2189 state = D_STATE(ifp); 2190 2191 ifo = ifp->options; 2192 if (state->arping_index != -1 && 2193 state->arping_index < ifo->arping_len && 2194 amsg && 2195 amsg->sip.s_addr == ifo->arping[state->arping_index]) 2196 { 2197 char buf[HWADDR_LEN * 3]; 2198 2199 hwaddr_ntoa(amsg->sha, ifp->hwlen, buf, sizeof(buf)); 2200 if (dhcpcd_selectprofile(ifp, buf) == -1 && 2201 dhcpcd_selectprofile(ifp, inet_ntoa(amsg->sip)) == -1) 2202 { 2203 /* We didn't find a profile for this 2204 * address or hwaddr, so move to the next 2205 * arping profile */ 2206 dhcp_arp_not_found(astate); 2207 return; 2208 } 2209 arp_free(astate); 2210 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2211 dhcpcd_startinterface(ifp); 2212 return; 2213 } 2214 #else 2215 UNUSED(amsg); 2216 #endif 2217 2218 addr = astate->addr; 2219 arp_free(astate); 2220 dhcp_addr_duplicated(ifp, &addr); 2221 } 2222 #endif 2223 2224 #endif /* ARP */ 2225 2226 void 2227 dhcp_bind(struct interface *ifp) 2228 { 2229 struct dhcpcd_ctx *ctx = ifp->ctx; 2230 struct dhcp_state *state = D_STATE(ifp); 2231 struct if_options *ifo = ifp->options; 2232 struct dhcp_lease *lease = &state->lease; 2233 uint8_t old_state; 2234 2235 state->reason = NULL; 2236 /* If we don't have an offer, we are re-binding a lease on preference, 2237 * normally when two interfaces have a lease matching IP addresses. */ 2238 if (state->offer) { 2239 free(state->old); 2240 state->old = state->new; 2241 state->old_len = state->new_len; 2242 state->new = state->offer; 2243 state->new_len = state->offer_len; 2244 state->offer = NULL; 2245 state->offer_len = 0; 2246 } 2247 get_lease(ifp, lease, state->new, state->new_len); 2248 if (ifo->options & DHCPCD_STATIC) { 2249 loginfox("%s: using static address %s/%d", 2250 ifp->name, inet_ntoa(lease->addr), 2251 inet_ntocidr(lease->mask)); 2252 lease->leasetime = DHCP_INFINITE_LIFETIME; 2253 state->reason = "STATIC"; 2254 } else if (ifo->options & DHCPCD_INFORM) { 2255 loginfox("%s: received approval for %s", 2256 ifp->name, inet_ntoa(lease->addr)); 2257 lease->leasetime = DHCP_INFINITE_LIFETIME; 2258 state->reason = "INFORM"; 2259 } else { 2260 if (lease->frominfo) 2261 state->reason = "TIMEOUT"; 2262 if (lease->leasetime == DHCP_INFINITE_LIFETIME) { 2263 lease->renewaltime = 2264 lease->rebindtime = 2265 lease->leasetime; 2266 loginfox("%s: leased %s for infinity", 2267 ifp->name, inet_ntoa(lease->addr)); 2268 } else { 2269 if (lease->leasetime < DHCP_MIN_LEASE) { 2270 logwarnx("%s: minimum lease is %d seconds", 2271 ifp->name, DHCP_MIN_LEASE); 2272 lease->leasetime = DHCP_MIN_LEASE; 2273 } 2274 if (lease->rebindtime == 0) 2275 lease->rebindtime = 2276 (uint32_t)(lease->leasetime * T2); 2277 else if (lease->rebindtime >= lease->leasetime) { 2278 lease->rebindtime = 2279 (uint32_t)(lease->leasetime * T2); 2280 logwarnx("%s: rebind time greater than lease " 2281 "time, forcing to %"PRIu32" seconds", 2282 ifp->name, lease->rebindtime); 2283 } 2284 if (lease->renewaltime == 0) 2285 lease->renewaltime = 2286 (uint32_t)(lease->leasetime * T1); 2287 else if (lease->renewaltime > lease->rebindtime) { 2288 lease->renewaltime = 2289 (uint32_t)(lease->leasetime * T1); 2290 logwarnx("%s: renewal time greater than " 2291 "rebind time, forcing to %"PRIu32" seconds", 2292 ifp->name, lease->renewaltime); 2293 } 2294 if (state->state == DHS_RENEW && state->addr && 2295 lease->addr.s_addr == state->addr->addr.s_addr && 2296 !(state->added & STATE_FAKE)) 2297 logdebugx("%s: leased %s for %"PRIu32" seconds", 2298 ifp->name, inet_ntoa(lease->addr), 2299 lease->leasetime); 2300 else 2301 loginfox("%s: leased %s for %"PRIu32" seconds", 2302 ifp->name, inet_ntoa(lease->addr), 2303 lease->leasetime); 2304 } 2305 } 2306 if (ctx->options & DHCPCD_TEST) { 2307 state->reason = "TEST"; 2308 script_runreason(ifp, state->reason); 2309 eloop_exit(ctx->eloop, EXIT_SUCCESS); 2310 return; 2311 } 2312 if (state->reason == NULL) { 2313 if (state->old && 2314 !(state->added & (STATE_FAKE | STATE_EXPIRED))) 2315 { 2316 if (state->old->yiaddr == state->new->yiaddr && 2317 lease->server.s_addr && 2318 state->state != DHS_REBIND) 2319 state->reason = "RENEW"; 2320 else 2321 state->reason = "REBIND"; 2322 } else if (state->state == DHS_REBOOT) 2323 state->reason = "REBOOT"; 2324 else 2325 state->reason = "BOUND"; 2326 } 2327 if (lease->leasetime == DHCP_INFINITE_LIFETIME) 2328 lease->renewaltime = lease->rebindtime = lease->leasetime; 2329 else { 2330 eloop_timeout_add_sec(ctx->eloop, 2331 lease->renewaltime, dhcp_startrenew, ifp); 2332 eloop_timeout_add_sec(ctx->eloop, 2333 lease->rebindtime, dhcp_rebind, ifp); 2334 eloop_timeout_add_sec(ctx->eloop, 2335 lease->leasetime, dhcp_expire, ifp); 2336 logdebugx("%s: renew in %"PRIu32" seconds, rebind in %"PRIu32 2337 " seconds", 2338 ifp->name, lease->renewaltime, lease->rebindtime); 2339 } 2340 state->state = DHS_BOUND; 2341 if (!state->lease.frominfo && 2342 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))) { 2343 logdebugx("%s: writing lease: %s", 2344 ifp->name, state->leasefile); 2345 if (dhcp_writefile(ifp->ctx, state->leasefile, 0640, 2346 state->new, state->new_len) == -1) 2347 logerr("dhcp_writefile: %s", state->leasefile); 2348 } 2349 2350 old_state = state->added; 2351 2352 if (!(ifo->options & DHCPCD_CONFIGURE)) { 2353 struct ipv4_addr *ia; 2354 2355 script_runreason(ifp, state->reason); 2356 dhcpcd_daemonise(ifp->ctx); 2357 2358 /* We we are not configuring the address, we need to keep 2359 * the BPF socket open if the address does not exist. */ 2360 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL); 2361 if (ia != NULL) { 2362 state->addr = ia; 2363 state->added = STATE_ADDED; 2364 dhcp_closebpf(ifp); 2365 goto openudp; 2366 } 2367 return; 2368 } 2369 2370 /* Add the address */ 2371 if (ipv4_applyaddr(ifp) == NULL) { 2372 /* There was an error adding the address. 2373 * If we are in oneshot, exit with a failure. */ 2374 if (ctx->options & DHCPCD_ONESHOT) { 2375 loginfox("exiting due to oneshot"); 2376 eloop_exit(ctx->eloop, EXIT_FAILURE); 2377 } 2378 return; 2379 } 2380 2381 /* Close the BPF filter as we can now receive DHCP messages 2382 * on a UDP socket. */ 2383 dhcp_closebpf(ifp); 2384 2385 openudp: 2386 /* If not in manager mode, open an address specific socket. */ 2387 if (ctx->options & DHCPCD_MANAGER || 2388 ifo->options & DHCPCD_STATIC || 2389 (state->old != NULL && 2390 state->old->yiaddr == state->new->yiaddr && 2391 old_state & STATE_ADDED && !(old_state & STATE_FAKE))) 2392 return; 2393 2394 dhcp_closeinet(ifp); 2395 #ifdef PRIVSEP 2396 if (IN_PRIVSEP_SE(ctx)) { 2397 if (ps_inet_openbootp(state->addr) == -1) 2398 logerr(__func__); 2399 return; 2400 } 2401 #endif 2402 2403 state->udp_rfd = dhcp_openudp(&state->addr->addr); 2404 if (state->udp_rfd == -1) { 2405 logerr(__func__); 2406 /* Address sharing without manager mode is not supported. 2407 * It's also possible another DHCP client could be running, 2408 * which is even worse. 2409 * We still need to work, so re-open BPF. */ 2410 dhcp_openbpf(ifp); 2411 return; 2412 } 2413 if (eloop_event_add(ctx->eloop, state->udp_rfd, ELE_READ, 2414 dhcp_handleifudp, ifp) == -1) 2415 logerr("%s: eloop_event_add", __func__); 2416 } 2417 2418 static size_t 2419 dhcp_message_new(struct bootp **bootp, 2420 const struct in_addr *addr, const struct in_addr *mask) 2421 { 2422 uint8_t *p; 2423 uint32_t cookie; 2424 2425 if ((*bootp = calloc(1, sizeof(**bootp))) == NULL) 2426 return 0; 2427 2428 (*bootp)->yiaddr = addr->s_addr; 2429 p = (*bootp)->vend; 2430 2431 cookie = htonl(MAGIC_COOKIE); 2432 memcpy(p, &cookie, sizeof(cookie)); 2433 p += sizeof(cookie); 2434 2435 if (mask->s_addr != INADDR_ANY) { 2436 *p++ = DHO_SUBNETMASK; 2437 *p++ = sizeof(mask->s_addr); 2438 memcpy(p, &mask->s_addr, sizeof(mask->s_addr)); 2439 p+= sizeof(mask->s_addr); 2440 } 2441 2442 *p = DHO_END; 2443 return sizeof(**bootp); 2444 } 2445 2446 #if defined(ARP) || defined(KERNEL_RFC5227) 2447 static int 2448 dhcp_arp_address(struct interface *ifp) 2449 { 2450 struct dhcp_state *state; 2451 struct in_addr addr; 2452 struct ipv4_addr *ia; 2453 2454 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2455 2456 state = D_STATE(ifp); 2457 addr.s_addr = state->offer->yiaddr == INADDR_ANY ? 2458 state->offer->ciaddr : state->offer->yiaddr; 2459 /* If the interface already has the address configured 2460 * then we can't ARP for duplicate detection. */ 2461 ia = ipv4_iffindaddr(ifp, &addr, NULL); 2462 #ifdef IN_IFF_NOTUSEABLE 2463 if (ia == NULL || ia->addr_flags & IN_IFF_NOTUSEABLE) { 2464 state->state = DHS_PROBE; 2465 if (ia == NULL) { 2466 struct dhcp_lease l; 2467 2468 get_lease(ifp, &l, state->offer, state->offer_len); 2469 /* Add the address now, let the kernel handle DAD. */ 2470 ipv4_addaddr(ifp, &l.addr, &l.mask, &l.brd, 2471 l.leasetime, l.rebindtime); 2472 } else if (ia->addr_flags & IN_IFF_DUPLICATED) 2473 dhcp_addr_duplicated(ifp, &ia->addr); 2474 else 2475 loginfox("%s: waiting for DAD on %s", 2476 ifp->name, inet_ntoa(addr)); 2477 return 0; 2478 } 2479 #else 2480 if (!(ifp->flags & IFF_NOARP) && 2481 ifp->options->options & DHCPCD_ARP) 2482 { 2483 struct arp_state *astate; 2484 struct dhcp_lease l; 2485 2486 /* Even if the address exists, we need to defend it. */ 2487 astate = dhcp_arp_new(ifp, &addr); 2488 if (astate == NULL) 2489 return -1; 2490 2491 if (ia == NULL) { 2492 state->state = DHS_PROBE; 2493 get_lease(ifp, &l, state->offer, state->offer_len); 2494 loginfox("%s: probing address %s/%d", 2495 ifp->name, inet_ntoa(l.addr), inet_ntocidr(l.mask)); 2496 /* We need to handle DAD. */ 2497 arp_probe(astate); 2498 return 0; 2499 } 2500 } 2501 #endif 2502 2503 return 1; 2504 } 2505 2506 static void 2507 dhcp_arp_bind(struct interface *ifp) 2508 { 2509 2510 if (ifp->ctx->options & DHCPCD_TEST || 2511 dhcp_arp_address(ifp) == 1) 2512 dhcp_bind(ifp); 2513 } 2514 #endif 2515 2516 static void 2517 dhcp_lastlease(void *arg) 2518 { 2519 struct interface *ifp = arg; 2520 struct dhcp_state *state = D_STATE(ifp); 2521 2522 loginfox("%s: timed out contacting a DHCP server, using last lease", 2523 ifp->name); 2524 #if defined(ARP) || defined(KERNEL_RFC5227) 2525 dhcp_arp_bind(ifp); 2526 #else 2527 dhcp_bind(ifp); 2528 #endif 2529 /* Set expired here because dhcp_bind() -> ipv4_addaddr() will reset 2530 * state */ 2531 state->added |= STATE_EXPIRED; 2532 state->interval = 0; 2533 dhcp_discover(ifp); 2534 } 2535 2536 static void 2537 dhcp_static(struct interface *ifp) 2538 { 2539 struct if_options *ifo; 2540 struct dhcp_state *state; 2541 struct ipv4_addr *ia; 2542 2543 state = D_STATE(ifp); 2544 ifo = ifp->options; 2545 2546 ia = NULL; 2547 if (ifo->req_addr.s_addr == INADDR_ANY && 2548 (ia = ipv4_iffindaddr(ifp, NULL, NULL)) == NULL) 2549 { 2550 loginfox("%s: waiting for 3rd party to " 2551 "configure IP address", ifp->name); 2552 state->reason = "3RDPARTY"; 2553 script_runreason(ifp, state->reason); 2554 return; 2555 } 2556 2557 state->offer_len = dhcp_message_new(&state->offer, 2558 ia ? &ia->addr : &ifo->req_addr, 2559 ia ? &ia->mask : &ifo->req_mask); 2560 if (state->offer_len) 2561 #if defined(ARP) || defined(KERNEL_RFC5227) 2562 dhcp_arp_bind(ifp); 2563 #else 2564 dhcp_bind(ifp); 2565 #endif 2566 } 2567 2568 void 2569 dhcp_inform(struct interface *ifp) 2570 { 2571 struct dhcp_state *state; 2572 struct if_options *ifo; 2573 struct ipv4_addr *ia; 2574 2575 state = D_STATE(ifp); 2576 ifo = ifp->options; 2577 2578 free(state->offer); 2579 state->offer = NULL; 2580 state->offer_len = 0; 2581 2582 if (ifo->req_addr.s_addr == INADDR_ANY) { 2583 ia = ipv4_iffindaddr(ifp, NULL, NULL); 2584 if (ia == NULL) { 2585 loginfox("%s: waiting for 3rd party to " 2586 "configure IP address", 2587 ifp->name); 2588 if (!(ifp->ctx->options & DHCPCD_TEST)) { 2589 state->reason = "3RDPARTY"; 2590 script_runreason(ifp, state->reason); 2591 } 2592 return; 2593 } 2594 } else { 2595 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, &ifo->req_mask); 2596 if (ia == NULL) { 2597 if (ifp->ctx->options & DHCPCD_TEST) { 2598 logerrx("%s: cannot add IP address in test mode", 2599 ifp->name); 2600 return; 2601 } 2602 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, NULL); 2603 if (ia != NULL) 2604 /* Netmask must be different, delete it. */ 2605 ipv4_deladdr(ia, 1); 2606 state->offer_len = dhcp_message_new(&state->offer, 2607 &ifo->req_addr, &ifo->req_mask); 2608 #ifdef ARP 2609 if (dhcp_arp_address(ifp) != 1) 2610 return; 2611 #endif 2612 ia = ipv4_iffindaddr(ifp, 2613 &ifo->req_addr, &ifo->req_mask); 2614 assert(ia != NULL); 2615 } 2616 } 2617 2618 state->state = DHS_INFORM; 2619 state->addr = ia; 2620 state->offer_len = dhcp_message_new(&state->offer, 2621 &ia->addr, &ia->mask); 2622 if (state->offer_len) { 2623 dhcp_new_xid(ifp); 2624 get_lease(ifp, &state->lease, state->offer, state->offer_len); 2625 send_inform(ifp); 2626 } 2627 } 2628 2629 void 2630 dhcp_reboot_newopts(struct interface *ifp, unsigned long long oldopts) 2631 { 2632 struct if_options *ifo; 2633 struct dhcp_state *state = D_STATE(ifp); 2634 2635 if (state == NULL || state->state == DHS_NONE) 2636 return; 2637 ifo = ifp->options; 2638 if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC) && 2639 (state->addr == NULL || 2640 state->addr->addr.s_addr != ifo->req_addr.s_addr)) || 2641 (oldopts & (DHCPCD_INFORM | DHCPCD_STATIC) && 2642 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC)))) 2643 { 2644 dhcp_drop(ifp, "EXPIRE"); 2645 } 2646 } 2647 2648 #ifdef ARP 2649 static int 2650 dhcp_activeaddr(const struct interface *ifp, const struct in_addr *addr) 2651 { 2652 const struct interface *ifp1; 2653 const struct dhcp_state *state; 2654 2655 TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) { 2656 if (ifp1 == ifp) 2657 continue; 2658 if ((state = D_CSTATE(ifp1)) == NULL) 2659 continue; 2660 switch(state->state) { 2661 case DHS_REBOOT: 2662 case DHS_RENEW: 2663 case DHS_REBIND: 2664 case DHS_BOUND: 2665 case DHS_INFORM: 2666 break; 2667 default: 2668 continue; 2669 } 2670 if (state->lease.addr.s_addr == addr->s_addr) 2671 return 1; 2672 } 2673 return 0; 2674 } 2675 #endif 2676 2677 static void 2678 dhcp_reboot(struct interface *ifp) 2679 { 2680 struct if_options *ifo; 2681 struct dhcp_state *state = D_STATE(ifp); 2682 #ifdef ARP 2683 struct ipv4_addr *ia; 2684 #endif 2685 2686 if (state == NULL || state->state == DHS_NONE) 2687 return; 2688 ifo = ifp->options; 2689 state->state = DHS_REBOOT; 2690 state->interval = 0; 2691 2692 if (ifo->options & DHCPCD_LINK && !if_is_link_up(ifp)) { 2693 loginfox("%s: waiting for carrier", ifp->name); 2694 return; 2695 } 2696 if (ifo->options & DHCPCD_STATIC) { 2697 dhcp_static(ifp); 2698 return; 2699 } 2700 if (ifo->options & DHCPCD_INFORM) { 2701 loginfox("%s: informing address of %s", 2702 ifp->name, inet_ntoa(state->lease.addr)); 2703 dhcp_inform(ifp); 2704 return; 2705 } 2706 if (ifo->reboot == 0 || state->offer == NULL) { 2707 dhcp_discover(ifp); 2708 return; 2709 } 2710 if (!IS_DHCP(state->offer)) 2711 return; 2712 2713 loginfox("%s: rebinding lease of %s", 2714 ifp->name, inet_ntoa(state->lease.addr)); 2715 2716 #ifdef ARP 2717 #ifndef KERNEL_RFC5227 2718 /* Create the DHCP ARP state so we can defend it. */ 2719 (void)dhcp_arp_new(ifp, &state->lease.addr); 2720 #endif 2721 2722 /* If the address exists on the interface and no other interface 2723 * is currently using it then announce it to ensure this 2724 * interface gets the reply. */ 2725 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL); 2726 if (ia != NULL && 2727 !(ifp->ctx->options & DHCPCD_TEST) && 2728 #ifdef IN_IFF_NOTUSEABLE 2729 !(ia->addr_flags & IN_IFF_NOTUSEABLE) && 2730 #endif 2731 dhcp_activeaddr(ifp, &state->lease.addr) == 0) 2732 arp_ifannounceaddr(ifp, &state->lease.addr); 2733 #endif 2734 2735 dhcp_new_xid(ifp); 2736 state->lease.server.s_addr = INADDR_ANY; 2737 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2738 2739 #ifdef IPV4LL 2740 /* Need to add this before dhcp_expire and friends. */ 2741 if (!ifo->fallback && ifo->options & DHCPCD_IPV4LL) 2742 eloop_timeout_add_sec(ifp->ctx->eloop, 2743 ifo->reboot, ipv4ll_start, ifp); 2744 #endif 2745 2746 if (ifo->options & DHCPCD_LASTLEASE && state->lease.frominfo) 2747 eloop_timeout_add_sec(ifp->ctx->eloop, 2748 ifo->reboot, dhcp_lastlease, ifp); 2749 else if (!(ifo->options & DHCPCD_INFORM)) 2750 eloop_timeout_add_sec(ifp->ctx->eloop, 2751 ifo->reboot, dhcp_expire, ifp); 2752 2753 /* Don't bother ARP checking as the server could NAK us first. 2754 * Don't call dhcp_request as that would change the state */ 2755 send_request(ifp); 2756 } 2757 2758 void 2759 dhcp_drop(struct interface *ifp, const char *reason) 2760 { 2761 struct dhcp_state *state = D_STATE(ifp); 2762 2763 /* dhcp_start may just have been called and we don't yet have a state 2764 * but we do have a timeout, so punt it. */ 2765 if (state == NULL || state->state == DHS_NONE) { 2766 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2767 return; 2768 } 2769 2770 #ifdef ARP 2771 if (state->addr != NULL) 2772 arp_freeaddr(ifp, &state->addr->addr); 2773 #endif 2774 #ifdef ARPING 2775 state->arping_index = -1; 2776 #endif 2777 2778 if (ifp->options->options & DHCPCD_RELEASE && 2779 !(ifp->options->options & DHCPCD_INFORM)) 2780 { 2781 /* Failure to send the release may cause this function to 2782 * re-enter so guard by setting the state. */ 2783 if (state->state == DHS_RELEASE) 2784 return; 2785 state->state = DHS_RELEASE; 2786 2787 dhcp_unlink(ifp->ctx, state->leasefile); 2788 if (if_is_link_up(ifp) && 2789 state->new != NULL && 2790 state->lease.server.s_addr != INADDR_ANY) 2791 { 2792 loginfox("%s: releasing lease of %s", 2793 ifp->name, inet_ntoa(state->lease.addr)); 2794 dhcp_new_xid(ifp); 2795 send_message(ifp, DHCP_RELEASE, NULL); 2796 } 2797 } 2798 #ifdef AUTH 2799 else if (state->auth.reconf != NULL) { 2800 /* 2801 * Drop the lease as the token may only be present 2802 * in the initial reply message and not subsequent 2803 * renewals. 2804 * If dhcpcd is restarted, the token is lost. 2805 * XXX persist this in another file? 2806 */ 2807 dhcp_unlink(ifp->ctx, state->leasefile); 2808 } 2809 #endif 2810 2811 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 2812 #ifdef AUTH 2813 dhcp_auth_reset(&state->auth); 2814 #endif 2815 2816 state->state = DHS_NONE; 2817 free(state->offer); 2818 state->offer = NULL; 2819 state->offer_len = 0; 2820 free(state->old); 2821 state->old = state->new; 2822 state->old_len = state->new_len; 2823 state->new = NULL; 2824 state->new_len = 0; 2825 state->reason = reason; 2826 if (ifp->options->options & DHCPCD_CONFIGURE) 2827 ipv4_applyaddr(ifp); 2828 else { 2829 state->addr = NULL; 2830 state->added = 0; 2831 script_runreason(ifp, state->reason); 2832 } 2833 free(state->old); 2834 state->old = NULL; 2835 state->old_len = 0; 2836 state->lease.addr.s_addr = 0; 2837 ifp->options->options &= ~(DHCPCD_CSR_WARNED | 2838 DHCPCD_ROUTER_HOST_ROUTE_WARNED); 2839 2840 /* Close DHCP ports so a changed interface family is picked 2841 * up by a new BPF state. */ 2842 dhcp_close(ifp); 2843 } 2844 2845 static int 2846 blacklisted_ip(const struct if_options *ifo, in_addr_t addr) 2847 { 2848 size_t i; 2849 2850 for (i = 0; i < ifo->blacklist_len; i += 2) 2851 if (ifo->blacklist[i] == (addr & ifo->blacklist[i + 1])) 2852 return 1; 2853 return 0; 2854 } 2855 2856 #define WHTLST_NONE 0 2857 #define WHTLST_MATCH 1 2858 #define WHTLST_NOMATCH 2 2859 static unsigned int 2860 whitelisted_ip(const struct if_options *ifo, in_addr_t addr) 2861 { 2862 size_t i; 2863 2864 if (ifo->whitelist_len == 0) 2865 return WHTLST_NONE; 2866 for (i = 0; i < ifo->whitelist_len; i += 2) 2867 if (ifo->whitelist[i] == (addr & ifo->whitelist[i + 1])) 2868 return WHTLST_MATCH; 2869 return WHTLST_NOMATCH; 2870 } 2871 2872 static void 2873 log_dhcp(int loglevel, const char *msg, 2874 const struct interface *ifp, const struct bootp *bootp, size_t bootp_len, 2875 const struct in_addr *from, int ad) 2876 { 2877 const char *tfrom; 2878 char *a, sname[sizeof(bootp->sname) * 4]; 2879 struct in_addr addr; 2880 int r; 2881 uint8_t overl; 2882 2883 if (strcmp(msg, "NAK:") == 0) { 2884 a = get_option_string(ifp->ctx, bootp, bootp_len, DHO_MESSAGE); 2885 if (a) { 2886 char *tmp; 2887 size_t al, tmpl; 2888 2889 al = strlen(a); 2890 tmpl = (al * 4) + 1; 2891 tmp = malloc(tmpl); 2892 if (tmp == NULL) { 2893 logerr(__func__); 2894 free(a); 2895 return; 2896 } 2897 print_string(tmp, tmpl, OT_STRING, (uint8_t *)a, al); 2898 free(a); 2899 a = tmp; 2900 } 2901 } else if (ad && bootp->yiaddr != 0) { 2902 addr.s_addr = bootp->yiaddr; 2903 a = strdup(inet_ntoa(addr)); 2904 if (a == NULL) { 2905 logerr(__func__); 2906 return; 2907 } 2908 } else 2909 a = NULL; 2910 2911 tfrom = "from"; 2912 r = get_option_addr(ifp->ctx, &addr, bootp, bootp_len, DHO_SERVERID); 2913 if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len, 2914 DHO_OPTSOVERLOADED) == -1) 2915 overl = 0; 2916 if (bootp->sname[0] && r == 0 && !(overl & 2)) { 2917 print_string(sname, sizeof(sname), OT_STRING | OT_DOMAIN, 2918 bootp->sname, sizeof(bootp->sname)); 2919 if (a == NULL) 2920 logmessage(loglevel, "%s: %s %s %s %s", 2921 ifp->name, msg, tfrom, inet_ntoa(addr), sname); 2922 else 2923 logmessage(loglevel, "%s: %s %s %s %s %s", 2924 ifp->name, msg, a, tfrom, inet_ntoa(addr), sname); 2925 } else { 2926 if (r != 0) { 2927 tfrom = "via"; 2928 addr = *from; 2929 } 2930 if (a == NULL) 2931 logmessage(loglevel, "%s: %s %s %s", 2932 ifp->name, msg, tfrom, inet_ntoa(addr)); 2933 else 2934 logmessage(loglevel, "%s: %s %s %s %s", 2935 ifp->name, msg, a, tfrom, inet_ntoa(addr)); 2936 } 2937 free(a); 2938 } 2939 2940 /* If we're sharing the same IP address with another interface on the 2941 * same network, we may receive the DHCP reply on the wrong interface. 2942 * Try and re-direct it here. */ 2943 static void 2944 dhcp_redirect_dhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len, 2945 const struct in_addr *from) 2946 { 2947 struct interface *ifn; 2948 const struct dhcp_state *state; 2949 uint32_t xid; 2950 2951 xid = ntohl(bootp->xid); 2952 TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) { 2953 if (ifn == ifp) 2954 continue; 2955 state = D_CSTATE(ifn); 2956 if (state == NULL || state->state == DHS_NONE) 2957 continue; 2958 if (state->xid != xid) 2959 continue; 2960 if (ifn->hwlen <= sizeof(bootp->chaddr) && 2961 memcmp(bootp->chaddr, ifn->hwaddr, ifn->hwlen)) 2962 continue; 2963 logdebugx("%s: redirecting DHCP message to %s", 2964 ifp->name, ifn->name); 2965 dhcp_handledhcp(ifn, bootp, bootp_len, from); 2966 } 2967 } 2968 2969 static void 2970 dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len, 2971 const struct in_addr *from) 2972 { 2973 struct dhcp_state *state = D_STATE(ifp); 2974 struct if_options *ifo = ifp->options; 2975 struct dhcp_lease *lease = &state->lease; 2976 uint8_t type, tmp; 2977 struct in_addr addr; 2978 unsigned int i; 2979 char *msg; 2980 bool bootp_copied; 2981 uint32_t v6only_time = 0; 2982 bool use_v6only = false; 2983 #ifdef AUTH 2984 const uint8_t *auth; 2985 size_t auth_len; 2986 #endif 2987 #ifdef IN_IFF_DUPLICATED 2988 struct ipv4_addr *ia; 2989 #endif 2990 2991 #define LOGDHCP0(l, m) \ 2992 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 0) 2993 #define LOGDHCP(l, m) \ 2994 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 1) 2995 2996 #define IS_STATE_ACTIVE(s) ((s)-state != DHS_NONE && \ 2997 (s)->state != DHS_INIT && (s)->state != DHS_BOUND) 2998 2999 if (bootp->op != BOOTREPLY) { 3000 if (IS_STATE_ACTIVE(state)) 3001 logdebugx("%s: op (%d) is not BOOTREPLY", 3002 ifp->name, bootp->op); 3003 return; 3004 } 3005 3006 if (state->xid != ntohl(bootp->xid)) { 3007 if (IS_STATE_ACTIVE(state)) 3008 logdebugx("%s: wrong xid 0x%x (expecting 0x%x) from %s", 3009 ifp->name, ntohl(bootp->xid), state->xid, 3010 inet_ntoa(*from)); 3011 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from); 3012 return; 3013 } 3014 3015 if (ifp->hwlen <= sizeof(bootp->chaddr) && 3016 memcmp(bootp->chaddr, ifp->hwaddr, ifp->hwlen)) 3017 { 3018 if (IS_STATE_ACTIVE(state)) { 3019 char buf[sizeof(bootp->chaddr) * 3]; 3020 3021 logdebugx("%s: xid 0x%x is for hwaddr %s", 3022 ifp->name, ntohl(bootp->xid), 3023 hwaddr_ntoa(bootp->chaddr, sizeof(bootp->chaddr), 3024 buf, sizeof(buf))); 3025 } 3026 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from); 3027 return; 3028 } 3029 3030 if (!ifp->active) 3031 return; 3032 3033 i = whitelisted_ip(ifp->options, from->s_addr); 3034 switch (i) { 3035 case WHTLST_NOMATCH: 3036 logwarnx("%s: non whitelisted DHCP packet from %s", 3037 ifp->name, inet_ntoa(*from)); 3038 return; 3039 case WHTLST_MATCH: 3040 break; 3041 case WHTLST_NONE: 3042 if (blacklisted_ip(ifp->options, from->s_addr) == 1) { 3043 logwarnx("%s: blacklisted DHCP packet from %s", 3044 ifp->name, inet_ntoa(*from)); 3045 return; 3046 } 3047 } 3048 3049 /* We may have found a BOOTP server */ 3050 if (get_option_uint8(ifp->ctx, &type, 3051 bootp, bootp_len, DHO_MESSAGETYPE) == -1) 3052 type = 0; 3053 else if (ifo->options & DHCPCD_BOOTP) { 3054 logdebugx("%s: ignoring DHCP reply (expecting BOOTP)", 3055 ifp->name); 3056 return; 3057 } 3058 3059 #ifdef AUTH 3060 /* Authenticate the message */ 3061 auth = get_option(ifp->ctx, bootp, bootp_len, 3062 DHO_AUTHENTICATION, &auth_len); 3063 if (auth) { 3064 if (dhcp_auth_validate(&state->auth, &ifo->auth, 3065 (uint8_t *)bootp, bootp_len, 4, type, 3066 auth, auth_len) == NULL) 3067 { 3068 LOGDHCP0(LOG_ERR, "authentication failed"); 3069 return; 3070 } 3071 if (state->auth.token) 3072 logdebugx("%s: validated using 0x%08" PRIu32, 3073 ifp->name, state->auth.token->secretid); 3074 else 3075 loginfox("%s: accepted reconfigure key", ifp->name); 3076 } else if (ifo->auth.options & DHCPCD_AUTH_SEND) { 3077 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) { 3078 LOGDHCP0(LOG_ERR, "no authentication"); 3079 return; 3080 } 3081 LOGDHCP0(LOG_WARNING, "no authentication"); 3082 } 3083 #endif 3084 3085 /* RFC 3203 */ 3086 if (type == DHCP_FORCERENEW) { 3087 if (from->s_addr == INADDR_ANY || 3088 from->s_addr == INADDR_BROADCAST) 3089 { 3090 LOGDHCP(LOG_ERR, "discarding Force Renew"); 3091 return; 3092 } 3093 #ifdef AUTH 3094 if (auth == NULL) { 3095 LOGDHCP(LOG_ERR, "unauthenticated Force Renew"); 3096 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) 3097 return; 3098 } 3099 if (state->state != DHS_BOUND && state->state != DHS_INFORM) { 3100 LOGDHCP(LOG_DEBUG, "not bound, ignoring Force Renew"); 3101 return; 3102 } 3103 LOGDHCP(LOG_INFO, "Force Renew from"); 3104 /* The rebind and expire timings are still the same, we just 3105 * enter the renew state early */ 3106 if (state->state == DHS_BOUND) 3107 dhcp_renew(ifp); 3108 else { 3109 eloop_timeout_delete(ifp->ctx->eloop, 3110 send_inform, ifp); 3111 dhcp_inform(ifp); 3112 } 3113 #else 3114 LOGDHCP(LOG_ERR, "unauthenticated Force Renew"); 3115 #endif 3116 return; 3117 } 3118 3119 if (state->state == DHS_BOUND) { 3120 LOGDHCP(LOG_DEBUG, "bound, ignoring"); 3121 return; 3122 } 3123 3124 if (state->state == DHS_PROBE) { 3125 /* Ignore any DHCP messages whilst probing a lease to bind. */ 3126 LOGDHCP(LOG_DEBUG, "probing, ignoring"); 3127 return; 3128 } 3129 3130 /* reset the message counter */ 3131 state->interval = 0; 3132 3133 /* Ensure that no reject options are present */ 3134 for (i = 1; i < 255; i++) { 3135 if (has_option_mask(ifo->rejectmask, i) && 3136 get_option_uint8(ifp->ctx, &tmp, 3137 bootp, bootp_len, (uint8_t)i) == 0) 3138 { 3139 LOGDHCP(LOG_WARNING, "reject DHCP"); 3140 return; 3141 } 3142 } 3143 3144 if (type == DHCP_NAK) { 3145 /* For NAK, only check if we require the ServerID */ 3146 if (has_option_mask(ifo->requiremask, DHO_SERVERID) && 3147 get_option_addr(ifp->ctx, &addr, 3148 bootp, bootp_len, DHO_SERVERID) == -1) 3149 { 3150 LOGDHCP(LOG_WARNING, "reject NAK"); 3151 return; 3152 } 3153 3154 /* We should restart on a NAK */ 3155 LOGDHCP(LOG_WARNING, "NAK:"); 3156 if ((msg = get_option_string(ifp->ctx, 3157 bootp, bootp_len, DHO_MESSAGE))) 3158 { 3159 logwarnx("%s: message: %s", ifp->name, msg); 3160 free(msg); 3161 } 3162 if (state->state == DHS_INFORM) /* INFORM should not be NAKed */ 3163 return; 3164 if (!(ifp->ctx->options & DHCPCD_TEST)) { 3165 dhcp_drop(ifp, "NAK"); 3166 dhcp_unlink(ifp->ctx, state->leasefile); 3167 } 3168 3169 /* If we constantly get NAKS then we should slowly back off */ 3170 eloop_timeout_add_sec(ifp->ctx->eloop, 3171 state->nakoff, dhcp_discover, ifp); 3172 if (state->nakoff == 0) 3173 state->nakoff = 1; 3174 else { 3175 state->nakoff *= 2; 3176 if (state->nakoff > NAKOFF_MAX) 3177 state->nakoff = NAKOFF_MAX; 3178 } 3179 return; 3180 } 3181 3182 /* Ensure that all required options are present */ 3183 for (i = 1; i < 255; i++) { 3184 if (has_option_mask(ifo->requiremask, i) && 3185 get_option_uint8(ifp->ctx, &tmp, 3186 bootp, bootp_len, (uint8_t)i) != 0) 3187 { 3188 /* If we are BOOTP, then ignore the need for serverid. 3189 * To ignore BOOTP, require dhcp_message_type. 3190 * However, nothing really stops BOOTP from providing 3191 * DHCP style options as well so the above isn't 3192 * always true. */ 3193 if (type == 0 && i == DHO_SERVERID) 3194 continue; 3195 LOGDHCP(LOG_WARNING, "reject DHCP"); 3196 return; 3197 } 3198 } 3199 3200 if (has_option_mask(ifo->requestmask, DHO_IPV6_PREFERRED_ONLY)) { 3201 if (get_option_uint32(ifp->ctx, &v6only_time, bootp, bootp_len, 3202 DHO_IPV6_PREFERRED_ONLY) == 0 && 3203 (state->state == DHS_DISCOVER || state->state == DHS_REBOOT)) 3204 { 3205 char v6msg[128]; 3206 3207 use_v6only = true; 3208 if (v6only_time < MIN_V6ONLY_WAIT) 3209 v6only_time = MIN_V6ONLY_WAIT; 3210 snprintf(v6msg, sizeof(v6msg), 3211 "IPv6-Only Preferred received (%u seconds)", 3212 v6only_time); 3213 LOGDHCP(LOG_INFO, v6msg); 3214 } 3215 } 3216 3217 /* DHCP Auto-Configure, RFC 2563 */ 3218 if (type == DHCP_OFFER && bootp->yiaddr == 0) { 3219 LOGDHCP(LOG_WARNING, "no address given"); 3220 if ((msg = get_option_string(ifp->ctx, 3221 bootp, bootp_len, DHO_MESSAGE))) 3222 { 3223 logwarnx("%s: message: %s", ifp->name, msg); 3224 free(msg); 3225 } 3226 #ifdef IPV4LL 3227 if (state->state == DHS_DISCOVER && 3228 get_option_uint8(ifp->ctx, &tmp, bootp, bootp_len, 3229 DHO_AUTOCONFIGURE) == 0) 3230 { 3231 switch (tmp) { 3232 case 0: 3233 LOGDHCP(LOG_WARNING, "IPv4LL disabled from"); 3234 ipv4ll_drop(ifp); 3235 #ifdef ARP 3236 arp_drop(ifp); 3237 #endif 3238 break; 3239 case 1: 3240 LOGDHCP(LOG_WARNING, "IPv4LL enabled from"); 3241 ipv4ll_start(ifp); 3242 break; 3243 default: 3244 logerrx("%s: unknown auto configuration " 3245 "option %d", 3246 ifp->name, tmp); 3247 break; 3248 } 3249 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3250 eloop_timeout_add_sec(ifp->ctx->eloop, 3251 use_v6only ? v6only_time : DHCP_MAX, 3252 dhcp_discover, ifp); 3253 } 3254 #endif 3255 return; 3256 } 3257 3258 if (use_v6only) { 3259 dhcp_drop(ifp, "EXPIRE"); 3260 dhcp_unlink(ifp->ctx, state->leasefile); 3261 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3262 eloop_timeout_add_sec(ifp->ctx->eloop, v6only_time, 3263 dhcp_discover, ifp); 3264 return; 3265 } 3266 3267 /* Ensure that the address offered is valid */ 3268 if ((type == 0 || type == DHCP_OFFER || type == DHCP_ACK) && 3269 (bootp->ciaddr == INADDR_ANY || bootp->ciaddr == INADDR_BROADCAST) 3270 && 3271 (bootp->yiaddr == INADDR_ANY || bootp->yiaddr == INADDR_BROADCAST)) 3272 { 3273 LOGDHCP(LOG_WARNING, "reject invalid address"); 3274 return; 3275 } 3276 3277 #ifdef IN_IFF_DUPLICATED 3278 ia = ipv4_iffindaddr(ifp, &lease->addr, NULL); 3279 if (ia && ia->addr_flags & IN_IFF_DUPLICATED) { 3280 LOGDHCP(LOG_WARNING, "declined duplicate address"); 3281 if (type) 3282 dhcp_decline(ifp); 3283 ipv4_deladdr(ia, 0); 3284 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3285 eloop_timeout_add_sec(ifp->ctx->eloop, 3286 DHCP_RAND_MAX, dhcp_discover, ifp); 3287 return; 3288 } 3289 #endif 3290 3291 bootp_copied = false; 3292 if ((type == 0 || type == DHCP_OFFER) && state->state == DHS_DISCOVER) { 3293 lease->frominfo = 0; 3294 lease->addr.s_addr = bootp->yiaddr; 3295 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie)); 3296 if (type == 0 || 3297 get_option_addr(ifp->ctx, 3298 &lease->server, bootp, bootp_len, DHO_SERVERID) != 0) 3299 lease->server.s_addr = INADDR_ANY; 3300 3301 /* Test for rapid commit in the OFFER */ 3302 if (!(ifp->ctx->options & DHCPCD_TEST) && 3303 has_option_mask(ifo->requestmask, DHO_RAPIDCOMMIT) && 3304 get_option(ifp->ctx, bootp, bootp_len, 3305 DHO_RAPIDCOMMIT, NULL)) 3306 { 3307 state->state = DHS_REQUEST; 3308 goto rapidcommit; 3309 } 3310 3311 LOGDHCP(LOG_INFO, "offered"); 3312 if (state->offer_len < bootp_len) { 3313 free(state->offer); 3314 if ((state->offer = malloc(bootp_len)) == NULL) { 3315 logerr(__func__); 3316 state->offer_len = 0; 3317 return; 3318 } 3319 } 3320 state->offer_len = bootp_len; 3321 memcpy(state->offer, bootp, bootp_len); 3322 bootp_copied = true; 3323 if (ifp->ctx->options & DHCPCD_TEST) { 3324 free(state->old); 3325 state->old = state->new; 3326 state->old_len = state->new_len; 3327 state->new = state->offer; 3328 state->new_len = state->offer_len; 3329 state->offer = NULL; 3330 state->offer_len = 0; 3331 state->reason = "TEST"; 3332 script_runreason(ifp, state->reason); 3333 eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS); 3334 if (state->bpf) 3335 state->bpf->bpf_flags |= BPF_EOF; 3336 return; 3337 } 3338 eloop_timeout_delete(ifp->ctx->eloop, send_discover, ifp); 3339 /* We don't request BOOTP addresses */ 3340 if (type) { 3341 /* We used to ARP check here, but that seems to be in 3342 * violation of RFC2131 where it only describes 3343 * DECLINE after REQUEST. 3344 * It also seems that some MS DHCP servers actually 3345 * ignore DECLINE if no REQUEST, ie we decline a 3346 * DISCOVER. */ 3347 dhcp_request(ifp); 3348 return; 3349 } 3350 } 3351 3352 if (type) { 3353 if (type == DHCP_OFFER) { 3354 LOGDHCP(LOG_WARNING, "ignoring offer of"); 3355 return; 3356 } 3357 3358 /* We should only be dealing with acks */ 3359 if (type != DHCP_ACK) { 3360 LOGDHCP(LOG_ERR, "not ACK or OFFER"); 3361 return; 3362 } 3363 3364 if (state->state == DHS_DISCOVER) { 3365 /* We only allow ACK of rapid commit DISCOVER. */ 3366 if (has_option_mask(ifo->requestmask, 3367 DHO_RAPIDCOMMIT) && 3368 get_option(ifp->ctx, bootp, bootp_len, 3369 DHO_RAPIDCOMMIT, NULL)) 3370 state->state = DHS_REQUEST; 3371 else { 3372 LOGDHCP(LOG_DEBUG, "ignoring ack of"); 3373 return; 3374 } 3375 } 3376 3377 rapidcommit: 3378 if (!(ifo->options & DHCPCD_INFORM)) 3379 LOGDHCP(LOG_DEBUG, "acknowledged"); 3380 else 3381 ifo->options &= ~DHCPCD_STATIC; 3382 } 3383 3384 /* No NAK, so reset the backoff 3385 * We don't reset on an OFFER message because the server could 3386 * potentially NAK the REQUEST. */ 3387 state->nakoff = 0; 3388 3389 /* BOOTP could have already assigned this above. */ 3390 if (!bootp_copied) { 3391 if (state->offer_len < bootp_len) { 3392 free(state->offer); 3393 if ((state->offer = malloc(bootp_len)) == NULL) { 3394 logerr(__func__); 3395 state->offer_len = 0; 3396 return; 3397 } 3398 } 3399 state->offer_len = bootp_len; 3400 memcpy(state->offer, bootp, bootp_len); 3401 } 3402 3403 lease->frominfo = 0; 3404 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp); 3405 3406 #if defined(ARP) || defined(KERNEL_RFC5227) 3407 dhcp_arp_bind(ifp); 3408 #else 3409 dhcp_bind(ifp); 3410 #endif 3411 } 3412 3413 static void * 3414 get_udp_data(void *packet, size_t *len) 3415 { 3416 const struct ip *ip = packet; 3417 size_t ip_hl = (size_t)ip->ip_hl * 4; 3418 char *p = packet; 3419 3420 p += ip_hl + sizeof(struct udphdr); 3421 *len = (size_t)ntohs(ip->ip_len) - sizeof(struct udphdr) - ip_hl; 3422 return p; 3423 } 3424 3425 static bool 3426 is_packet_udp_bootp(void *packet, size_t plen) 3427 { 3428 struct ip *ip = packet; 3429 size_t ip_hlen; 3430 struct udphdr udp; 3431 3432 if (plen < sizeof(*ip)) 3433 return false; 3434 3435 if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP) 3436 return false; 3437 3438 /* Sanity. */ 3439 if (ntohs(ip->ip_len) > plen) 3440 return false; 3441 3442 ip_hlen = (size_t)ip->ip_hl * 4; 3443 if (ip_hlen < sizeof(*ip)) 3444 return false; 3445 3446 /* Check we have a UDP header and BOOTP. */ 3447 if (ip_hlen + sizeof(udp) + offsetof(struct bootp, vend) > plen) 3448 return false; 3449 3450 /* Sanity. */ 3451 memcpy(&udp, (char *)ip + ip_hlen, sizeof(udp)); 3452 if (ntohs(udp.uh_ulen) < sizeof(udp)) 3453 return false; 3454 if (ip_hlen + ntohs(udp.uh_ulen) > plen) 3455 return false; 3456 3457 /* Check it's to the right port. */ 3458 if (udp.uh_dport != htons(BOOTPC)) 3459 return false; 3460 3461 return true; 3462 } 3463 3464 /* Lengths have already been checked. */ 3465 static bool 3466 checksums_valid(void *packet, 3467 struct in_addr *from, unsigned int flags) 3468 { 3469 struct ip *ip = packet; 3470 union pip { 3471 struct ip ip; 3472 uint16_t w[sizeof(struct ip) / 2]; 3473 } pip = { 3474 .ip = { 3475 .ip_p = IPPROTO_UDP, 3476 .ip_src = ip->ip_src, 3477 .ip_dst = ip->ip_dst, 3478 } 3479 }; 3480 size_t ip_hlen; 3481 struct udphdr udp; 3482 char *udpp, *uh_sump; 3483 uint32_t csum; 3484 3485 if (from != NULL) 3486 from->s_addr = ip->ip_src.s_addr; 3487 3488 ip_hlen = (size_t)ip->ip_hl * 4; 3489 if (in_cksum(ip, ip_hlen, NULL) != 0) 3490 return false; 3491 3492 if (flags & BPF_PARTIALCSUM) 3493 return true; 3494 3495 udpp = (char *)ip + ip_hlen; 3496 memcpy(&udp, udpp, sizeof(udp)); 3497 if (udp.uh_sum == 0) 3498 return true; 3499 3500 /* UDP checksum is based on a pseudo IP header alongside 3501 * the UDP header and payload. */ 3502 pip.ip.ip_len = udp.uh_ulen; 3503 csum = 0; 3504 3505 /* Need to zero the UDP sum in the packet for the checksum to work. */ 3506 uh_sump = udpp + offsetof(struct udphdr, uh_sum); 3507 memset(uh_sump, 0, sizeof(udp.uh_sum)); 3508 3509 /* Checksum pseudo header and then UDP + payload. */ 3510 in_cksum(pip.w, sizeof(pip.w), &csum); 3511 csum = in_cksum(udpp, ntohs(udp.uh_ulen), &csum); 3512 3513 #if 0 /* Not needed, just here for completeness. */ 3514 /* Put the checksum back. */ 3515 memcpy(uh_sump, &udp.uh_sum, sizeof(udp.uh_sum)); 3516 #endif 3517 3518 return csum == udp.uh_sum; 3519 } 3520 3521 static void 3522 dhcp_handlebootp(struct interface *ifp, struct bootp *bootp, size_t len, 3523 struct in_addr *from) 3524 { 3525 size_t v; 3526 3527 if (len < offsetof(struct bootp, vend)) { 3528 logerrx("%s: truncated packet (%zu) from %s", 3529 ifp->name, len, inet_ntoa(*from)); 3530 return; 3531 } 3532 3533 /* Unlikely, but appeases sanitizers. */ 3534 if (len > FRAMELEN_MAX) { 3535 logerrx("%s: packet exceeded frame length (%zu) from %s", 3536 ifp->name, len, inet_ntoa(*from)); 3537 return; 3538 } 3539 3540 /* To make our IS_DHCP macro easy, ensure the vendor 3541 * area has at least 4 octets. */ 3542 v = len - offsetof(struct bootp, vend); 3543 while (v < 4) { 3544 bootp->vend[v++] = '\0'; 3545 len++; 3546 } 3547 3548 dhcp_handledhcp(ifp, bootp, len, from); 3549 } 3550 3551 void 3552 dhcp_packet(struct interface *ifp, uint8_t *data, size_t len, 3553 unsigned int bpf_flags) 3554 { 3555 struct bootp *bootp; 3556 struct in_addr from; 3557 size_t udp_len; 3558 size_t fl = bpf_frame_header_len(ifp); 3559 #ifdef PRIVSEP 3560 const struct dhcp_state *state = D_CSTATE(ifp); 3561 3562 /* It's possible that an interface departs and arrives in short 3563 * order to receive a BPF frame out of order. 3564 * There is a similar check in ARP, but much lower down the stack. 3565 * It's not needed for other inet protocols because we send the 3566 * message as a whole and select the interface off that and then 3567 * check state. BPF on the other hand is very interface 3568 * specific and we do need this check. */ 3569 if (state == NULL) 3570 return; 3571 3572 /* Ignore double reads */ 3573 if (IN_PRIVSEP(ifp->ctx)) { 3574 switch (state->state) { 3575 case DHS_BOUND: /* FALLTHROUGH */ 3576 case DHS_RENEW: 3577 return; 3578 default: 3579 break; 3580 } 3581 } 3582 #endif 3583 3584 /* Trim frame header */ 3585 if (fl != 0) { 3586 if (len < fl) { 3587 logerrx("%s: %s: short frame header %zu", 3588 __func__, ifp->name, len); 3589 return; 3590 } 3591 len -= fl; 3592 /* Move the data to avoid alignment errors. */ 3593 memmove(data, data + fl, len); 3594 } 3595 3596 /* Validate filter. */ 3597 if (!is_packet_udp_bootp(data, len)) { 3598 #ifdef BPF_DEBUG 3599 logerrx("%s: DHCP BPF validation failure", ifp->name); 3600 #endif 3601 return; 3602 } 3603 3604 if (!checksums_valid(data, &from, bpf_flags)) { 3605 logerrx("%s: checksum failure from %s", 3606 ifp->name, inet_ntoa(from)); 3607 return; 3608 } 3609 3610 /* 3611 * DHCP has a variable option area rather than a fixed vendor area. 3612 * Because DHCP uses the BOOTP protocol it should still send BOOTP 3613 * sized packets to be RFC compliant. 3614 * However some servers send a truncated vendor area. 3615 * dhcpcd can work fine without the vendor area being sent. 3616 */ 3617 bootp = get_udp_data(data, &udp_len); 3618 dhcp_handlebootp(ifp, bootp, udp_len, &from); 3619 } 3620 3621 static void 3622 dhcp_readbpf(void *arg, unsigned short events) 3623 { 3624 struct interface *ifp = arg; 3625 uint8_t buf[FRAMELEN_MAX]; 3626 ssize_t bytes; 3627 struct dhcp_state *state = D_STATE(ifp); 3628 struct bpf *bpf = state->bpf; 3629 3630 if (events != ELE_READ) 3631 logerrx("%s: unexpected event 0x%04x", __func__, events); 3632 3633 bpf->bpf_flags &= ~BPF_EOF; 3634 while (!(bpf->bpf_flags & BPF_EOF)) { 3635 bytes = bpf_read(bpf, buf, sizeof(buf)); 3636 if (bytes == -1) { 3637 if (state->state != DHS_NONE) { 3638 logerr("%s: %s", __func__, ifp->name); 3639 dhcp_close(ifp); 3640 } 3641 break; 3642 } 3643 dhcp_packet(ifp, buf, (size_t)bytes, bpf->bpf_flags); 3644 /* Check we still have a state after processing. */ 3645 if ((state = D_STATE(ifp)) == NULL) 3646 break; 3647 if ((bpf = state->bpf) == NULL) 3648 break; 3649 } 3650 } 3651 3652 void 3653 dhcp_recvmsg(struct dhcpcd_ctx *ctx, struct msghdr *msg) 3654 { 3655 struct sockaddr_in *from = (struct sockaddr_in *)msg->msg_name; 3656 struct iovec *iov = &msg->msg_iov[0]; 3657 struct interface *ifp; 3658 const struct dhcp_state *state; 3659 3660 ifp = if_findifpfromcmsg(ctx, msg, NULL); 3661 if (ifp == NULL) { 3662 logerr(__func__); 3663 return; 3664 } 3665 state = D_CSTATE(ifp); 3666 if (state == NULL) { 3667 /* Try re-directing it to another interface. */ 3668 dhcp_redirect_dhcp(ifp, (struct bootp *)iov->iov_base, 3669 iov->iov_len, &from->sin_addr); 3670 return; 3671 } 3672 3673 if (state->bpf != NULL) { 3674 /* Avoid a duplicate read if BPF is open for the interface. */ 3675 return; 3676 } 3677 #ifdef PRIVSEP 3678 if (IN_PRIVSEP(ctx)) { 3679 switch (state->state) { 3680 case DHS_BOUND: /* FALLTHROUGH */ 3681 case DHS_RENEW: 3682 break; 3683 default: 3684 /* Any other state we ignore it or will receive 3685 * via BPF. */ 3686 return; 3687 } 3688 } 3689 #endif 3690 3691 dhcp_handlebootp(ifp, iov->iov_base, iov->iov_len, 3692 &from->sin_addr); 3693 } 3694 3695 static void 3696 dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp, 3697 unsigned short events) 3698 { 3699 const struct dhcp_state *state; 3700 struct sockaddr_in from; 3701 union { 3702 struct bootp bootp; 3703 uint8_t buf[10 * 1024]; /* Maximum MTU */ 3704 } iovbuf; 3705 struct iovec iov = { 3706 .iov_base = iovbuf.buf, 3707 .iov_len = sizeof(iovbuf.buf), 3708 }; 3709 union { 3710 struct cmsghdr hdr; 3711 #ifdef IP_RECVIF 3712 uint8_t buf[CMSG_SPACE(sizeof(struct sockaddr_dl))]; 3713 #else 3714 uint8_t buf[CMSG_SPACE(sizeof(struct in_pktinfo))]; 3715 #endif 3716 } cmsgbuf = { .buf = { 0 } }; 3717 struct msghdr msg = { 3718 .msg_name = &from, .msg_namelen = sizeof(from), 3719 .msg_iov = &iov, .msg_iovlen = 1, 3720 .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf), 3721 }; 3722 int s; 3723 ssize_t bytes; 3724 3725 if (events != ELE_READ) 3726 logerrx("%s: unexpected event 0x%04x", __func__, events); 3727 3728 if (ifp != NULL) { 3729 state = D_CSTATE(ifp); 3730 s = state->udp_rfd; 3731 } else 3732 s = ctx->udp_rfd; 3733 3734 bytes = recvmsg(s, &msg, 0); 3735 if (bytes == -1) { 3736 logerr(__func__); 3737 return; 3738 } 3739 3740 iov.iov_len = (size_t)bytes; 3741 dhcp_recvmsg(ctx, &msg); 3742 } 3743 3744 static void 3745 dhcp_handleudp(void *arg, unsigned short events) 3746 { 3747 struct dhcpcd_ctx *ctx = arg; 3748 3749 dhcp_readudp(ctx, NULL, events); 3750 } 3751 3752 static void 3753 dhcp_handleifudp(void *arg, unsigned short events) 3754 { 3755 struct interface *ifp = arg; 3756 3757 dhcp_readudp(ifp->ctx, ifp, events); 3758 } 3759 3760 static int 3761 dhcp_openbpf(struct interface *ifp) 3762 { 3763 struct dhcp_state *state; 3764 3765 state = D_STATE(ifp); 3766 3767 #ifdef PRIVSEP 3768 if (IN_PRIVSEP_SE(ifp->ctx)) { 3769 if (ps_bpf_openbootp(ifp) == -1) { 3770 logerr(__func__); 3771 return -1; 3772 } 3773 return 0; 3774 } 3775 #endif 3776 3777 if (state->bpf != NULL) 3778 return 0; 3779 3780 state->bpf = bpf_open(ifp, bpf_bootp, NULL); 3781 if (state->bpf == NULL) { 3782 if (errno == ENOENT) { 3783 logerrx("%s not found", bpf_name); 3784 /* May as well disable IPv4 entirely at 3785 * this point as we really need it. */ 3786 ifp->options->options &= ~DHCPCD_IPV4; 3787 } else 3788 logerr("%s: %s", __func__, ifp->name); 3789 return -1; 3790 } 3791 3792 if (eloop_event_add(ifp->ctx->eloop, state->bpf->bpf_fd, ELE_READ, 3793 dhcp_readbpf, ifp) == -1) 3794 logerr("%s: eloop_event_add", __func__); 3795 return 0; 3796 } 3797 3798 void 3799 dhcp_free(struct interface *ifp) 3800 { 3801 struct dhcp_state *state = D_STATE(ifp); 3802 struct dhcpcd_ctx *ctx; 3803 3804 dhcp_close(ifp); 3805 #ifdef ARP 3806 arp_drop(ifp); 3807 #endif 3808 if (state) { 3809 state->state = DHS_NONE; 3810 free(state->old); 3811 free(state->new); 3812 free(state->offer); 3813 free(state->clientid); 3814 free(state); 3815 } 3816 3817 ctx = ifp->ctx; 3818 /* If we don't have any more DHCP enabled interfaces, 3819 * close the global socket and release resources */ 3820 if (ctx->ifaces) { 3821 TAILQ_FOREACH(ifp, ctx->ifaces, next) { 3822 state = D_STATE(ifp); 3823 if (state != NULL && state->state != DHS_NONE) 3824 break; 3825 } 3826 } 3827 if (ifp == NULL) { 3828 if (ctx->udp_rfd != -1) { 3829 eloop_event_delete(ctx->eloop, ctx->udp_rfd); 3830 close(ctx->udp_rfd); 3831 ctx->udp_rfd = -1; 3832 } 3833 if (ctx->udp_wfd != -1) { 3834 close(ctx->udp_wfd); 3835 ctx->udp_wfd = -1; 3836 } 3837 3838 free(ctx->opt_buffer); 3839 ctx->opt_buffer = NULL; 3840 ctx->opt_buffer_len = 0; 3841 } 3842 } 3843 3844 static int 3845 dhcp_initstate(struct interface *ifp) 3846 { 3847 struct dhcp_state *state; 3848 3849 state = D_STATE(ifp); 3850 if (state != NULL) 3851 return 0; 3852 3853 ifp->if_data[IF_DATA_DHCP] = calloc(1, sizeof(*state)); 3854 state = D_STATE(ifp); 3855 if (state == NULL) 3856 return -1; 3857 3858 state->state = DHS_NONE; 3859 /* 0 is a valid fd, so init to -1 */ 3860 state->udp_rfd = -1; 3861 #ifdef ARPING 3862 state->arping_index = -1; 3863 #endif 3864 return 1; 3865 } 3866 3867 static int 3868 dhcp_init(struct interface *ifp) 3869 { 3870 struct dhcp_state *state; 3871 struct if_options *ifo; 3872 uint8_t len; 3873 char buf[(sizeof(ifo->clientid) - 1) * 3]; 3874 3875 if (dhcp_initstate(ifp) == -1) 3876 return -1; 3877 3878 state = D_STATE(ifp); 3879 state->state = DHS_INIT; 3880 state->reason = "PREINIT"; 3881 state->nakoff = 0; 3882 dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile), 3883 AF_INET, ifp); 3884 3885 ifo = ifp->options; 3886 /* We need to drop the leasefile so that dhcp_start 3887 * doesn't load it. */ 3888 if (ifo->options & DHCPCD_REQUEST) 3889 dhcp_unlink(ifp->ctx, state->leasefile); 3890 3891 free(state->clientid); 3892 state->clientid = NULL; 3893 3894 if (ifo->options & DHCPCD_ANONYMOUS) { 3895 /* Removing the option could show that we want anonymous. 3896 * As such keep it as it's already in the hwaddr field. */ 3897 goto make_clientid; 3898 } else if (*ifo->clientid) { 3899 state->clientid = malloc((size_t)(ifo->clientid[0] + 1)); 3900 if (state->clientid == NULL) 3901 goto eexit; 3902 memcpy(state->clientid, ifo->clientid, 3903 (size_t)(ifo->clientid[0]) + 1); 3904 } else if (ifo->options & DHCPCD_CLIENTID) { 3905 if (ifo->options & DHCPCD_DUID) { 3906 state->clientid = malloc(ifp->ctx->duid_len + 6); 3907 if (state->clientid == NULL) 3908 goto eexit; 3909 state->clientid[0] =(uint8_t)(ifp->ctx->duid_len + 5); 3910 state->clientid[1] = 255; /* RFC 4361 */ 3911 memcpy(state->clientid + 2, ifo->iaid, 4); 3912 memcpy(state->clientid + 6, ifp->ctx->duid, 3913 ifp->ctx->duid_len); 3914 } else { 3915 make_clientid: 3916 len = (uint8_t)(ifp->hwlen + 1); 3917 state->clientid = malloc((size_t)len + 1); 3918 if (state->clientid == NULL) 3919 goto eexit; 3920 state->clientid[0] = len; 3921 state->clientid[1] = (uint8_t)ifp->hwtype; 3922 memcpy(state->clientid + 2, ifp->hwaddr, 3923 ifp->hwlen); 3924 } 3925 } 3926 3927 if (ifo->options & DHCPCD_DUID) 3928 /* Don't bother logging as DUID and IAID are reported 3929 * at device start. */ 3930 return 0; 3931 3932 if (ifo->options & DHCPCD_CLIENTID && state->clientid != NULL) 3933 logdebugx("%s: using ClientID %s", ifp->name, 3934 hwaddr_ntoa(state->clientid + 1, state->clientid[0], 3935 buf, sizeof(buf))); 3936 else if (ifp->hwlen) 3937 logdebugx("%s: using hwaddr %s", ifp->name, 3938 hwaddr_ntoa(ifp->hwaddr, ifp->hwlen, buf, sizeof(buf))); 3939 return 0; 3940 3941 eexit: 3942 logerr(__func__); 3943 return -1; 3944 } 3945 3946 static void 3947 dhcp_start1(void *arg) 3948 { 3949 struct interface *ifp = arg; 3950 struct dhcpcd_ctx *ctx = ifp->ctx; 3951 struct if_options *ifo = ifp->options; 3952 struct dhcp_state *state; 3953 uint32_t l; 3954 int nolease; 3955 3956 if (!(ifo->options & DHCPCD_IPV4)) 3957 return; 3958 3959 /* Listen on *.*.*.*:bootpc so that the kernel never sends an 3960 * ICMP port unreachable message back to the DHCP server. 3961 * Only do this in manager mode so we don't swallow messages 3962 * for dhcpcd running on another interface. */ 3963 if ((ctx->options & (DHCPCD_MANAGER|DHCPCD_PRIVSEP)) == DHCPCD_MANAGER 3964 && ctx->udp_rfd == -1) 3965 { 3966 ctx->udp_rfd = dhcp_openudp(NULL); 3967 if (ctx->udp_rfd == -1) { 3968 logerr(__func__); 3969 return; 3970 } 3971 if (eloop_event_add(ctx->eloop, ctx->udp_rfd, ELE_READ, 3972 dhcp_handleudp, ctx) == -1) 3973 logerr("%s: eloop_event_add", __func__); 3974 } 3975 if (!IN_PRIVSEP(ctx) && ctx->udp_wfd == -1) { 3976 ctx->udp_wfd = xsocket(PF_INET, SOCK_RAW|SOCK_CXNB,IPPROTO_UDP); 3977 if (ctx->udp_wfd == -1) { 3978 logerr(__func__); 3979 return; 3980 } 3981 } 3982 3983 if (dhcp_init(ifp) == -1) { 3984 logerr("%s: dhcp_init", ifp->name); 3985 return; 3986 } 3987 3988 state = D_STATE(ifp); 3989 clock_gettime(CLOCK_MONOTONIC, &state->started); 3990 state->interval = 0; 3991 free(state->offer); 3992 state->offer = NULL; 3993 state->offer_len = 0; 3994 3995 #ifdef ARPING 3996 if (ifo->arping_len && state->arping_index < ifo->arping_len) { 3997 dhcp_arping(ifp); 3998 return; 3999 } 4000 #endif 4001 4002 if (ifo->options & DHCPCD_STATIC) { 4003 dhcp_static(ifp); 4004 return; 4005 } 4006 4007 if (ifo->options & DHCPCD_INFORM) { 4008 dhcp_inform(ifp); 4009 return; 4010 } 4011 4012 /* We don't want to read the old lease if we NAK an old test */ 4013 nolease = state->offer && ifp->ctx->options & DHCPCD_TEST; 4014 if (!nolease && ifo->options & DHCPCD_DHCP) { 4015 state->offer_len = read_lease(ifp, &state->offer); 4016 /* Check the saved lease matches the type we want */ 4017 if (state->offer) { 4018 #ifdef IN_IFF_DUPLICATED 4019 struct in_addr addr; 4020 struct ipv4_addr *ia; 4021 4022 addr.s_addr = state->offer->yiaddr; 4023 ia = ipv4_iffindaddr(ifp, &addr, NULL); 4024 #endif 4025 4026 if ((!IS_DHCP(state->offer) && 4027 !(ifo->options & DHCPCD_BOOTP)) || 4028 #ifdef IN_IFF_DUPLICATED 4029 (ia && ia->addr_flags & IN_IFF_DUPLICATED) || 4030 #endif 4031 (IS_DHCP(state->offer) && 4032 ifo->options & DHCPCD_BOOTP)) 4033 { 4034 free(state->offer); 4035 state->offer = NULL; 4036 state->offer_len = 0; 4037 } 4038 } 4039 } 4040 if (state->offer) { 4041 struct ipv4_addr *ia; 4042 time_t mtime; 4043 4044 get_lease(ifp, &state->lease, state->offer, state->offer_len); 4045 state->lease.frominfo = 1; 4046 if (state->new == NULL && 4047 (ia = ipv4_iffindaddr(ifp, 4048 &state->lease.addr, &state->lease.mask)) != NULL) 4049 { 4050 /* We still have the IP address from the last lease. 4051 * Fake add the address and routes from it so the lease 4052 * can be cleaned up. */ 4053 state->new = malloc(state->offer_len); 4054 if (state->new) { 4055 memcpy(state->new, 4056 state->offer, state->offer_len); 4057 state->new_len = state->offer_len; 4058 state->addr = ia; 4059 state->added |= STATE_ADDED | STATE_FAKE; 4060 rt_build(ifp->ctx, AF_INET); 4061 } else 4062 logerr(__func__); 4063 } 4064 if (!IS_DHCP(state->offer)) { 4065 free(state->offer); 4066 state->offer = NULL; 4067 state->offer_len = 0; 4068 } else if (!(ifo->options & DHCPCD_LASTLEASE_EXTEND) && 4069 state->lease.leasetime != DHCP_INFINITE_LIFETIME && 4070 dhcp_filemtime(ifp->ctx, state->leasefile, &mtime) == 0) 4071 { 4072 time_t now; 4073 4074 /* Offset lease times and check expiry */ 4075 now = time(NULL); 4076 if (now == -1 || 4077 (time_t)state->lease.leasetime < now - mtime) 4078 { 4079 logdebugx("%s: discarding expired lease", 4080 ifp->name); 4081 free(state->offer); 4082 state->offer = NULL; 4083 state->offer_len = 0; 4084 state->lease.addr.s_addr = 0; 4085 /* Technically we should discard the lease 4086 * as it's expired, just as DHCPv6 addresses 4087 * would be by the kernel. 4088 * However, this may violate POLA so 4089 * we currently leave it be. 4090 * If we get a totally different lease from 4091 * the DHCP server we'll drop it anyway, as 4092 * we will on any other event which would 4093 * trigger a lease drop. 4094 * This should only happen if dhcpcd stops 4095 * running and the lease expires before 4096 * dhcpcd starts again. */ 4097 #if 0 4098 if (state->new) 4099 dhcp_drop(ifp, "EXPIRE"); 4100 #endif 4101 } else { 4102 l = (uint32_t)(now - mtime); 4103 state->lease.leasetime -= l; 4104 state->lease.renewaltime -= l; 4105 state->lease.rebindtime -= l; 4106 } 4107 } 4108 } 4109 4110 #ifdef IPV4LL 4111 if (!(ifo->options & DHCPCD_DHCP)) { 4112 if (ifo->options & DHCPCD_IPV4LL) 4113 ipv4ll_start(ifp); 4114 return; 4115 } 4116 #endif 4117 4118 if (state->offer == NULL || 4119 !IS_DHCP(state->offer) || 4120 ifo->options & DHCPCD_ANONYMOUS) 4121 dhcp_discover(ifp); 4122 else 4123 dhcp_reboot(ifp); 4124 } 4125 4126 void 4127 dhcp_start(struct interface *ifp) 4128 { 4129 unsigned int delay; 4130 #ifdef ARPING 4131 const struct dhcp_state *state; 4132 #endif 4133 4134 if (!(ifp->options->options & DHCPCD_IPV4)) 4135 return; 4136 4137 /* If we haven't been given a netmask for our requested address, 4138 * set it now. */ 4139 if (ifp->options->req_addr.s_addr != INADDR_ANY && 4140 ifp->options->req_mask.s_addr == INADDR_ANY) 4141 ifp->options->req_mask.s_addr = 4142 ipv4_getnetmask(ifp->options->req_addr.s_addr); 4143 4144 /* If we haven't specified a ClientID and our hardware address 4145 * length is greater than BOOTP CHADDR then we enforce a ClientID 4146 * of the hardware address type and the hardware address. 4147 * If there is no hardware address and no ClientID set, 4148 * force a DUID based ClientID. */ 4149 if (ifp->hwlen > 16) 4150 ifp->options->options |= DHCPCD_CLIENTID; 4151 else if (ifp->hwlen == 0 && !(ifp->options->options & DHCPCD_CLIENTID)) 4152 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_DUID; 4153 4154 /* Firewire and InfiniBand interfaces require ClientID and 4155 * the broadcast option being set. */ 4156 switch (ifp->hwtype) { 4157 case ARPHRD_IEEE1394: /* FALLTHROUGH */ 4158 case ARPHRD_INFINIBAND: 4159 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_BROADCAST; 4160 break; 4161 } 4162 4163 /* If we violate RFC2131 section 3.7 then require ARP 4164 * to detect if any other client wants our address. */ 4165 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) 4166 ifp->options->options |= DHCPCD_ARP; 4167 4168 /* No point in delaying a static configuration */ 4169 if (ifp->options->options & DHCPCD_STATIC || 4170 !(ifp->options->options & DHCPCD_INITIAL_DELAY)) 4171 { 4172 dhcp_start1(ifp); 4173 return; 4174 } 4175 4176 #ifdef ARPING 4177 /* If we have arpinged then we have already delayed. */ 4178 state = D_CSTATE(ifp); 4179 if (state != NULL && state->arping_index != -1) { 4180 dhcp_start1(ifp); 4181 return; 4182 } 4183 #endif 4184 delay = MSEC_PER_SEC + 4185 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC); 4186 logdebugx("%s: delaying IPv4 for %0.1f seconds", 4187 ifp->name, (float)delay / MSEC_PER_SEC); 4188 4189 eloop_timeout_add_msec(ifp->ctx->eloop, delay, dhcp_start1, ifp); 4190 } 4191 4192 void 4193 dhcp_abort(struct interface *ifp) 4194 { 4195 struct dhcp_state *state; 4196 4197 state = D_STATE(ifp); 4198 #ifdef ARPING 4199 if (state != NULL) 4200 state->arping_index = -1; 4201 #endif 4202 4203 eloop_timeout_delete(ifp->ctx->eloop, dhcp_start1, ifp); 4204 4205 if (state != NULL && state->added) { 4206 rt_build(ifp->ctx, AF_INET); 4207 #ifdef ARP 4208 if (ifp->options->options & DHCPCD_ARP) 4209 arp_announceaddr(ifp->ctx, &state->addr->addr); 4210 #endif 4211 } 4212 } 4213 4214 struct ipv4_addr * 4215 dhcp_handleifa(int cmd, struct ipv4_addr *ia, pid_t pid) 4216 { 4217 struct interface *ifp; 4218 struct dhcp_state *state; 4219 struct if_options *ifo; 4220 uint8_t i; 4221 4222 ifp = ia->iface; 4223 state = D_STATE(ifp); 4224 if (state == NULL || state->state == DHS_NONE) 4225 return ia; 4226 4227 if (cmd == RTM_DELADDR) { 4228 if (state->addr == ia) { 4229 loginfox("%s: pid %d deleted IP address %s", 4230 ifp->name, pid, ia->saddr); 4231 dhcp_close(ifp); 4232 state->addr = NULL; 4233 /* Don't clear the added state as we need 4234 * to drop the lease. */ 4235 dhcp_drop(ifp, "EXPIRE"); 4236 dhcp_start1(ifp); 4237 return ia; 4238 } 4239 } 4240 4241 if (cmd != RTM_NEWADDR) 4242 return ia; 4243 4244 #ifdef IN_IFF_NOTUSEABLE 4245 if (!(ia->addr_flags & IN_IFF_NOTUSEABLE)) 4246 dhcp_finish_dad(ifp, &ia->addr); 4247 else if (ia->addr_flags & IN_IFF_DUPLICATED) 4248 return dhcp_addr_duplicated(ifp, &ia->addr) ? NULL : ia; 4249 #endif 4250 4251 ifo = ifp->options; 4252 4253 #ifdef PRIVSEP 4254 if (IN_PRIVSEP_SE(ifp->ctx) && 4255 !(ifp->ctx->options & (DHCPCD_MANAGER | DHCPCD_CONFIGURE)) && 4256 IN_ARE_ADDR_EQUAL(&state->lease.addr, &ia->addr)) 4257 { 4258 state->addr = ia; 4259 state->added = STATE_ADDED; 4260 dhcp_closebpf(ifp); 4261 if (ps_inet_openbootp(ia) == -1) 4262 logerr(__func__); 4263 } 4264 #endif 4265 4266 /* If we have requested a specific address, return now. 4267 * The below code is only for when inform or static has been 4268 * requested without a specific address. */ 4269 if (ifo->req_addr.s_addr != INADDR_ANY) 4270 return ia; 4271 4272 /* Only inform if we are NOT in the inform state or bound. */ 4273 if (ifo->options & DHCPCD_INFORM) { 4274 if (state->state != DHS_INFORM && state->state != DHS_BOUND) 4275 dhcp_inform(ifp); 4276 return ia; 4277 } 4278 4279 /* Static and inform are mutually exclusive. If not static, return. */ 4280 if (!(ifo->options & DHCPCD_STATIC)) 4281 return ia; 4282 4283 free(state->old); 4284 state->old = state->new; 4285 state->new_len = dhcp_message_new(&state->new, &ia->addr, &ia->mask); 4286 if (state->new == NULL) 4287 return ia; 4288 4289 if (ifp->flags & IFF_POINTOPOINT) { 4290 for (i = 1; i < 255; i++) 4291 if (i != DHO_ROUTER && has_option_mask(ifo->dstmask,i)) 4292 dhcp_message_add_addr(state->new, i, ia->brd); 4293 } 4294 4295 state->reason = "STATIC"; 4296 rt_build(ifp->ctx, AF_INET); 4297 script_runreason(ifp, state->reason); 4298 4299 return ia; 4300 } 4301 4302 #ifndef SMALL 4303 int 4304 dhcp_dump(struct interface *ifp) 4305 { 4306 struct dhcp_state *state; 4307 4308 ifp->if_data[IF_DATA_DHCP] = state = calloc(1, sizeof(*state)); 4309 if (state == NULL) { 4310 logerr(__func__); 4311 return -1; 4312 } 4313 state->new_len = read_lease(ifp, &state->new); 4314 if (state->new == NULL) { 4315 logerr("read_lease"); 4316 return -1; 4317 } 4318 state->reason = "DUMP"; 4319 return script_runreason(ifp, state->reason); 4320 } 4321 #endif 4322