contrib/dhcpcd/src/dhcp.c

   1 /* SPDX-License-Identifier: BSD-2-Clause */
   2 /*
   3  * dhcpcd - DHCP client daemon
   4  * Copyright (c) 2006-2020 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 /* Wait N nanoseconds between sending a RELEASE and dropping the address.
  88  * This gives the kernel enough time to actually send it. */
  89 #define RELEASE_DELAY_S         0
  90 #define RELEASE_DELAY_NS        10000000
  91
  92 #ifndef IPDEFTTL
  93 #define IPDEFTTL 64 /* RFC1340 */
  94 #endif
  95
  96 /* Support older systems with different defines */
  97 #if !defined(IP_RECVPKTINFO) && defined(IP_PKTINFO)
  98 #define IP_RECVPKTINFO IP_PKTINFO
  99 #endif
 100
 101 /* Assert the correct structure size for on wire */
 102 __CTASSERT(sizeof(struct ip)            == 20);
 103 __CTASSERT(sizeof(struct udphdr)        == 8);
 104 __CTASSERT(sizeof(struct bootp)         == 300);
 105
 106 struct dhcp_op {
 107         uint8_t value;
 108         const char *name;
 109 };
 110
 111 static const struct dhcp_op dhcp_ops[] = {
 112         { DHCP_DISCOVER,   "DISCOVER" },
 113         { DHCP_OFFER,      "OFFER" },
 114         { DHCP_REQUEST,    "REQUEST" },
 115         { DHCP_DECLINE,    "DECLINE" },
 116         { DHCP_ACK,        "ACK" },
 117         { DHCP_NAK,        "NAK" },
 118         { DHCP_RELEASE,    "RELEASE" },
 119         { DHCP_INFORM,     "INFORM" },
 120         { DHCP_FORCERENEW, "FORCERENEW"},
 121         { 0, NULL }
 122 };
 123
 124 static const char * const dhcp_params[] = {
 125         "ip_address",
 126         "subnet_cidr",
 127         "network_number",
 128         "filename",
 129         "server_name",
 130         NULL
 131 };
 132
 133 static int dhcp_openbpf(struct interface *);
 134 static void dhcp_start1(void *);
 135 #if defined(ARP) && (!defined(KERNEL_RFC5227) || defined(ARPING))
 136 static void dhcp_arp_found(struct arp_state *, const struct arp_msg *);
 137 #endif
 138 static void dhcp_handledhcp(struct interface *, struct bootp *, size_t,
 139     const struct in_addr *);
 140 static void dhcp_handleifudp(void *);
 141 static int dhcp_initstate(struct interface *);
 142
 143 void
 144 dhcp_printoptions(const struct dhcpcd_ctx *ctx,
 145     const struct dhcp_opt *opts, size_t opts_len)
 146 {
 147         const char * const *p;
 148         size_t i, j;
 149         const struct dhcp_opt *opt, *opt2;
 150         int cols;
 151
 152         for (p = dhcp_params; *p; p++)
 153                 printf("    %s\n", *p);
 154
 155         for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
 156                 for (j = 0, opt2 = opts; j < opts_len; j++, opt2++)
 157                         if (opt->option == opt2->option)
 158                                 break;
 159                 if (j == opts_len) {
 160                         cols = printf("%03d %s", opt->option, opt->var);
 161                         dhcp_print_option_encoding(opt, cols);
 162                 }
 163         }
 164         for (i = 0, opt = opts; i < opts_len; i++, opt++) {
 165                 cols = printf("%03d %s", opt->option, opt->var);
 166                 dhcp_print_option_encoding(opt, cols);
 167         }
 168 }
 169
 170 static const uint8_t *
 171 get_option(struct dhcpcd_ctx *ctx,
 172     const struct bootp *bootp, size_t bootp_len,
 173     unsigned int opt, size_t *opt_len)
 174 {
 175         const uint8_t *p, *e;
 176         uint8_t l, o, ol, overl, *bp;
 177         const uint8_t *op;
 178         size_t bl;
 179
 180         if (bootp == NULL || bootp_len < DHCP_MIN_LEN) {
 181                 errno = EINVAL;
 182                 return NULL;
 183         }
 184
 185         /* Check we have the magic cookie */
 186         if (!IS_DHCP(bootp)) {
 187                 errno = ENOTSUP;
 188                 return NULL;
 189         }
 190
 191         p = bootp->vend + 4; /* options after the 4 byte cookie */
 192         e = (const uint8_t *)bootp + bootp_len;
 193         ol = o = overl = 0;
 194         bp = NULL;
 195         op = NULL;
 196         bl = 0;
 197         while (p < e) {
 198                 o = *p++;
 199                 switch (o) {
 200                 case DHO_PAD:
 201                         /* No length to read */
 202                         continue;
 203                 case DHO_END:
 204                         if (overl & 1) {
 205                                 /* bit 1 set means parse boot file */
 206                                 overl = (uint8_t)(overl & ~1);
 207                                 p = bootp->file;
 208                                 e = p + sizeof(bootp->file);
 209                         } else if (overl & 2) {
 210                                 /* bit 2 set means parse server name */
 211                                 overl = (uint8_t)(overl & ~2);
 212                                 p = bootp->sname;
 213                                 e = p + sizeof(bootp->sname);
 214                         } else
 215                                 goto exit;
 216                         /* No length to read */
 217                         continue;
 218                 }
 219
 220                 /* Check we can read the length */
 221                 if (p == e) {
 222                         errno = EINVAL;
 223                         return NULL;
 224                 }
 225                 l = *p++;
 226
 227                 /* Check we can read the option data, if present */
 228                 if (p + l > e) {
 229                         errno = EINVAL;
 230                         return NULL;
 231                 }
 232
 233                 if (o == DHO_OPTSOVERLOADED) {
 234                         /* Ensure we only get this option once by setting
 235                          * the last bit as well as the value.
 236                          * This is valid because only the first two bits
 237                          * actually mean anything in RFC2132 Section 9.3 */
 238                         if (l == 1 && !overl)
 239                                 overl = 0x80 | p[0];
 240                 }
 241
 242                 if (o == opt) {
 243                         if (op) {
 244                                 /* We must concatonate the options. */
 245                                 if (bl + l > ctx->opt_buffer_len) {
 246                                         size_t pos;
 247                                         uint8_t *nb;
 248
 249                                         if (bp)
 250                                                 pos = (size_t)
 251                                                     (bp - ctx->opt_buffer);
 252                                         else
 253                                                 pos = 0;
 254                                         nb = realloc(ctx->opt_buffer, bl + l);
 255                                         if (nb == NULL)
 256                                                 return NULL;
 257                                         ctx->opt_buffer = nb;
 258                                         ctx->opt_buffer_len = bl + l;
 259                                         bp = ctx->opt_buffer + pos;
 260                                 }
 261                                 if (bp == NULL)
 262                                         bp = ctx->opt_buffer;
 263                                 memcpy(bp, op, ol);
 264                                 bp += ol;
 265                         }
 266                         ol = l;
 267                         op = p;
 268                         bl += ol;
 269                 }
 270                 p += l;
 271         }
 272
 273 exit:
 274         if (opt_len)
 275                 *opt_len = bl;
 276         if (bp) {
 277                 memcpy(bp, op, ol);
 278                 return (const uint8_t *)ctx->opt_buffer;
 279         }
 280         if (op)
 281                 return op;
 282         errno = ENOENT;
 283         return NULL;
 284 }
 285
 286 static int
 287 get_option_addr(struct dhcpcd_ctx *ctx,
 288     struct in_addr *a, const struct bootp *bootp, size_t bootp_len,
 289     uint8_t option)
 290 {
 291         const uint8_t *p;
 292         size_t len;
 293
 294         p = get_option(ctx, bootp, bootp_len, option, &len);
 295         if (!p || len < (ssize_t)sizeof(a->s_addr))
 296                 return -1;
 297         memcpy(&a->s_addr, p, sizeof(a->s_addr));
 298         return 0;
 299 }
 300
 301 static int
 302 get_option_uint32(struct dhcpcd_ctx *ctx,
 303     uint32_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
 304 {
 305         const uint8_t *p;
 306         size_t len;
 307         uint32_t d;
 308
 309         p = get_option(ctx, bootp, bootp_len, option, &len);
 310         if (!p || len < (ssize_t)sizeof(d))
 311                 return -1;
 312         memcpy(&d, p, sizeof(d));
 313         if (i)
 314                 *i = ntohl(d);
 315         return 0;
 316 }
 317
 318 static int
 319 get_option_uint16(struct dhcpcd_ctx *ctx,
 320     uint16_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
 321 {
 322         const uint8_t *p;
 323         size_t len;
 324         uint16_t d;
 325
 326         p = get_option(ctx, bootp, bootp_len, option, &len);
 327         if (!p || len < (ssize_t)sizeof(d))
 328                 return -1;
 329         memcpy(&d, p, sizeof(d));
 330         if (i)
 331                 *i = ntohs(d);
 332         return 0;
 333 }
 334
 335 static int
 336 get_option_uint8(struct dhcpcd_ctx *ctx,
 337     uint8_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
 338 {
 339         const uint8_t *p;
 340         size_t len;
 341
 342         p = get_option(ctx, bootp, bootp_len, option, &len);
 343         if (!p || len < (ssize_t)sizeof(*p))
 344                 return -1;
 345         if (i)
 346                 *i = *(p);
 347         return 0;
 348 }
 349
 350 ssize_t
 351 print_rfc3442(FILE *fp, const uint8_t *data, size_t data_len)
 352 {
 353         const uint8_t *p = data, *e;
 354         size_t ocets;
 355         uint8_t cidr;
 356         struct in_addr addr;
 357
 358         /* Minimum is 5 -first is CIDR and a router length of 4 */
 359         if (data_len < 5) {
 360                 errno = EINVAL;
 361                 return -1;
 362         }
 363
 364         e = p + data_len;
 365         while (p < e) {
 366                 if (p != data) {
 367                         if (fputc(' ', fp) == EOF)
 368                                 return -1;
 369                 }
 370                 cidr = *p++;
 371                 if (cidr > 32) {
 372                         errno = EINVAL;
 373                         return -1;
 374                 }
 375                 ocets = (size_t)(cidr + 7) / NBBY;
 376                 if (p + 4 + ocets > e) {
 377                         errno = ERANGE;
 378                         return -1;
 379                 }
 380                 /* If we have ocets then we have a destination and netmask */
 381                 addr.s_addr = 0;
 382                 if (ocets > 0) {
 383                         memcpy(&addr.s_addr, p, ocets);
 384                         p += ocets;
 385                 }
 386                 if (fprintf(fp, "%s/%d", inet_ntoa(addr), cidr) == -1)
 387                         return -1;
 388
 389                 /* Finally, snag the router */
 390                 memcpy(&addr.s_addr, p, 4);
 391                 p += 4;
 392                 if (fprintf(fp, " %s", inet_ntoa(addr)) == -1)
 393                         return -1;
 394         }
 395
 396         if (fputc('\0', fp) == EOF)
 397                 return -1;
 398         return 1;
 399 }
 400
 401 static int
 402 decode_rfc3442_rt(rb_tree_t *routes, struct interface *ifp,
 403     const uint8_t *data, size_t dl, const struct bootp *bootp)
 404 {
 405         const uint8_t *p = data;
 406         const uint8_t *e;
 407         uint8_t cidr;
 408         size_t ocets;
 409         struct rt *rt = NULL;
 410         struct in_addr dest, netmask, gateway;
 411         int n;
 412
 413         /* Minimum is 5 -first is CIDR and a router length of 4 */
 414         if (dl < 5) {
 415                 errno = EINVAL;
 416                 return -1;
 417         }
 418
 419         n = 0;
 420         e = p + dl;
 421         while (p < e) {
 422                 cidr = *p++;
 423                 if (cidr > 32) {
 424                         errno = EINVAL;
 425                         return -1;
 426                 }
 427
 428                 ocets = (size_t)(cidr + 7) / NBBY;
 429                 if (p + 4 + ocets > e) {
 430                         errno = ERANGE;
 431                         return -1;
 432                 }
 433
 434                 if ((rt = rt_new(ifp)) == NULL)
 435                         return -1;
 436
 437                 /* If we have ocets then we have a destination and netmask */
 438                 dest.s_addr = 0;
 439                 if (ocets > 0) {
 440                         memcpy(&dest.s_addr, p, ocets);
 441                         p += ocets;
 442                         netmask.s_addr = htonl(~0U << (32 - cidr));
 443                 } else
 444                         netmask.s_addr = 0;
 445
 446                 /* Finally, snag the router */
 447                 memcpy(&gateway.s_addr, p, 4);
 448                 p += 4;
 449
 450                 /* An on-link host route is normally set by having the
 451                  * gateway match the destination or assigned address */
 452                 if (gateway.s_addr == dest.s_addr ||
 453                     (gateway.s_addr == bootp->yiaddr ||
 454                     gateway.s_addr == bootp->ciaddr))
 455                 {
 456                         gateway.s_addr = INADDR_ANY;
 457                         netmask.s_addr = INADDR_BROADCAST;
 458                 }
 459                 if (netmask.s_addr == INADDR_BROADCAST)
 460                         rt->rt_flags = RTF_HOST;
 461
 462                 sa_in_init(&rt->rt_dest, &dest);
 463                 sa_in_init(&rt->rt_netmask, &netmask);
 464                 sa_in_init(&rt->rt_gateway, &gateway);
 465                 if (rt_proto_add(routes, rt))
 466                         n = 1;
 467         }
 468         return n;
 469 }
 470
 471 ssize_t
 472 print_rfc3361(FILE *fp, const uint8_t *data, size_t dl)
 473 {
 474         uint8_t enc;
 475         char sip[NS_MAXDNAME];
 476         struct in_addr addr;
 477
 478         if (dl < 2) {
 479                 errno = EINVAL;
 480                 return 0;
 481         }
 482
 483         enc = *data++;
 484         dl--;
 485         switch (enc) {
 486         case 0:
 487                 if (decode_rfc1035(sip, sizeof(sip), data, dl) == -1)
 488                         return -1;
 489                 if (efprintf(fp, "%s", sip) == -1)
 490                         return -1;
 491                 break;
 492         case 1:
 493                 if (dl % 4 != 0) {
 494                         errno = EINVAL;
 495                         break;
 496                 }
 497                 addr.s_addr = INADDR_BROADCAST;
 498                 for (;
 499                     dl != 0;
 500                     data += sizeof(addr.s_addr), dl -= sizeof(addr.s_addr))
 501                 {
 502                         memcpy(&addr.s_addr, data, sizeof(addr.s_addr));
 503                         if (fprintf(fp, "%s", inet_ntoa(addr)) == -1)
 504                                 return -1;
 505                         if (dl != sizeof(addr.s_addr)) {
 506                                 if (fputc(' ', fp) == EOF)
 507                                         return -1;
 508                         }
 509                 }
 510                 if (fputc('\0', fp) == EOF)
 511                         return -1;
 512                 break;
 513         default:
 514                 errno = EINVAL;
 515                 return 0;
 516         }
 517
 518         return 1;
 519 }
 520
 521 static char *
 522 get_option_string(struct dhcpcd_ctx *ctx,
 523     const struct bootp *bootp, size_t bootp_len, uint8_t option)
 524 {
 525         size_t len;
 526         const uint8_t *p;
 527         char *s;
 528
 529         p = get_option(ctx, bootp, bootp_len, option, &len);
 530         if (!p || len == 0 || *p == '\0')
 531                 return NULL;
 532
 533         s = malloc(sizeof(char) * (len + 1));
 534         if (s) {
 535                 memcpy(s, p, len);
 536                 s[len] = '\0';
 537         }
 538         return s;
 539 }
 540
 541 /* This calculates the netmask that we should use for static routes.
 542  * This IS different from the calculation used to calculate the netmask
 543  * for an interface address. */
 544 static uint32_t
 545 route_netmask(uint32_t ip_in)
 546 {
 547         /* used to be unsigned long - check if error */
 548         uint32_t p = ntohl(ip_in);
 549         uint32_t t;
 550
 551         if (IN_CLASSA(p))
 552                 t = ~IN_CLASSA_NET;
 553         else {
 554                 if (IN_CLASSB(p))
 555                         t = ~IN_CLASSB_NET;
 556                 else {
 557                         if (IN_CLASSC(p))
 558                                 t = ~IN_CLASSC_NET;
 559                         else
 560                                 t = 0;
 561                 }
 562         }
 563
 564         while (t & p)
 565                 t >>= 1;
 566
 567         return (htonl(~t));
 568 }
 569
 570 /* We need to obey routing options.
 571  * If we have a CSR then we only use that.
 572  * Otherwise we add static routes and then routers. */
 573 static int
 574 get_option_routes(rb_tree_t *routes, struct interface *ifp,
 575     const struct bootp *bootp, size_t bootp_len)
 576 {
 577         struct if_options *ifo = ifp->options;
 578         const uint8_t *p;
 579         const uint8_t *e;
 580         struct rt *rt = NULL;
 581         struct in_addr dest, netmask, gateway;
 582         size_t len;
 583         const char *csr = "";
 584         int n;
 585
 586         /* If we have CSR's then we MUST use these only */
 587         if (!has_option_mask(ifo->nomask, DHO_CSR))
 588                 p = get_option(ifp->ctx, bootp, bootp_len, DHO_CSR, &len);
 589         else
 590                 p = NULL;
 591         /* Check for crappy MS option */
 592         if (!p && !has_option_mask(ifo->nomask, DHO_MSCSR)) {
 593                 p = get_option(ifp->ctx, bootp, bootp_len, DHO_MSCSR, &len);
 594                 if (p)
 595                         csr = "MS ";
 596         }
 597         if (p && (n = decode_rfc3442_rt(routes, ifp, p, len, bootp)) != -1) {
 598                 const struct dhcp_state *state;
 599
 600                 state = D_CSTATE(ifp);
 601                 if (!(ifo->options & DHCPCD_CSR_WARNED) &&
 602                     !(state->added & STATE_FAKE))
 603                 {
 604                         logdebugx("%s: using %sClassless Static Routes",
 605                             ifp->name, csr);
 606                         ifo->options |= DHCPCD_CSR_WARNED;
 607                 }
 608                 return n;
 609         }
 610
 611         n = 0;
 612         /* OK, get our static routes first. */
 613         if (!has_option_mask(ifo->nomask, DHO_STATICROUTE))
 614                 p = get_option(ifp->ctx, bootp, bootp_len,
 615                     DHO_STATICROUTE, &len);
 616         else
 617                 p = NULL;
 618         /* RFC 2131 Section 5.8 states length MUST be in multiples of 8 */
 619         if (p && len % 8 == 0) {
 620                 e = p + len;
 621                 while (p < e) {
 622                         memcpy(&dest.s_addr, p, sizeof(dest.s_addr));
 623                         p += 4;
 624                         memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr));
 625                         p += 4;
 626                         /* RFC 2131 Section 5.8 states default route is
 627                          * illegal */
 628                         if (gateway.s_addr == INADDR_ANY)
 629                                 continue;
 630                         if ((rt = rt_new(ifp)) == NULL)
 631                                 return -1;
 632
 633                         /* A on-link host route is normally set by having the
 634                          * gateway match the destination or assigned address */
 635                         if (gateway.s_addr == dest.s_addr ||
 636                              (gateway.s_addr == bootp->yiaddr ||
 637                               gateway.s_addr == bootp->ciaddr))
 638                         {
 639                                 gateway.s_addr = INADDR_ANY;
 640                                 netmask.s_addr = INADDR_BROADCAST;
 641                         } else
 642                                 netmask.s_addr = route_netmask(dest.s_addr);
 643                         if (netmask.s_addr == INADDR_BROADCAST)
 644                                 rt->rt_flags = RTF_HOST;
 645
 646                         sa_in_init(&rt->rt_dest, &dest);
 647                         sa_in_init(&rt->rt_netmask, &netmask);
 648                         sa_in_init(&rt->rt_gateway, &gateway);
 649                         if (rt_proto_add(routes, rt))
 650                                 n++;
 651                 }
 652         }
 653
 654         /* Now grab our routers */
 655         if (!has_option_mask(ifo->nomask, DHO_ROUTER))
 656                 p = get_option(ifp->ctx, bootp, bootp_len, DHO_ROUTER, &len);
 657         else
 658                 p = NULL;
 659         if (p && len % 4 == 0) {
 660                 e = p + len;
 661                 dest.s_addr = INADDR_ANY;
 662                 netmask.s_addr = INADDR_ANY;
 663                 while (p < e) {
 664                         if ((rt = rt_new(ifp)) == NULL)
 665                                 return -1;
 666                         memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr));
 667                         p += 4;
 668                         sa_in_init(&rt->rt_dest, &dest);
 669                         sa_in_init(&rt->rt_netmask, &netmask);
 670                         sa_in_init(&rt->rt_gateway, &gateway);
 671                         if (rt_proto_add(routes, rt))
 672                                 n++;
 673                 }
 674         }
 675
 676         return n;
 677 }
 678
 679 uint16_t
 680 dhcp_get_mtu(const struct interface *ifp)
 681 {
 682         const struct dhcp_state *state;
 683         uint16_t mtu;
 684
 685         if (ifp->options->mtu)
 686                 return (uint16_t)ifp->options->mtu;
 687         mtu = 0; /* bogus gcc warning */
 688         if ((state = D_CSTATE(ifp)) == NULL ||
 689             has_option_mask(ifp->options->nomask, DHO_MTU) ||
 690             get_option_uint16(ifp->ctx, &mtu,
 691                               state->new, state->new_len, DHO_MTU) == -1)
 692                 return 0;
 693         return mtu;
 694 }
 695
 696 /* Grab our routers from the DHCP message and apply any MTU value
 697  * the message contains */
 698 int
 699 dhcp_get_routes(rb_tree_t *routes, struct interface *ifp)
 700 {
 701         const struct dhcp_state *state;
 702
 703         if ((state = D_CSTATE(ifp)) == NULL || !(state->added & STATE_ADDED))
 704                 return 0;
 705         return get_option_routes(routes, ifp, state->new, state->new_len);
 706 }
 707
 708 /* Assumes DHCP options */
 709 static int
 710 dhcp_message_add_addr(struct bootp *bootp,
 711     uint8_t type, struct in_addr addr)
 712 {
 713         uint8_t *p;
 714         size_t len;
 715
 716         p = bootp->vend;
 717         while (*p != DHO_END) {
 718                 p++;
 719                 p += *p + 1;
 720         }
 721
 722         len = (size_t)(p - bootp->vend);
 723         if (len + 6 > sizeof(bootp->vend)) {
 724                 errno = ENOMEM;
 725                 return -1;
 726         }
 727
 728         *p++ = type;
 729         *p++ = 4;
 730         memcpy(p, &addr.s_addr, 4);
 731         p += 4;
 732         *p = DHO_END;
 733         return 0;
 734 }
 735
 736 static ssize_t
 737 make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 738 {
 739         struct bootp *bootp;
 740         uint8_t *lp, *p, *e;
 741         uint8_t *n_params = NULL;
 742         uint32_t ul;
 743         uint16_t sz;
 744         size_t len, i;
 745         const struct dhcp_opt *opt;
 746         struct if_options *ifo = ifp->options;
 747         const struct dhcp_state *state = D_CSTATE(ifp);
 748         const struct dhcp_lease *lease = &state->lease;
 749         char hbuf[HOSTNAME_MAX_LEN + 1];
 750         const char *hostname;
 751         const struct vivco *vivco;
 752         int mtu;
 753 #ifdef AUTH
 754         uint8_t *auth, auth_len;
 755 #endif
 756
 757         if ((mtu = if_getmtu(ifp)) == -1)
 758                 logerr("%s: if_getmtu", ifp->name);
 759         else if (mtu < MTU_MIN) {
 760                 if (if_setmtu(ifp, MTU_MIN) == -1)
 761                         logerr("%s: if_setmtu", ifp->name);
 762                 mtu = MTU_MIN;
 763         }
 764
 765         if (ifo->options & DHCPCD_BOOTP)
 766                 bootp = calloc(1, sizeof (*bootp));
 767         else
 768                 /* Make the maximal message we could send */
 769                 bootp = calloc(1, (size_t)(mtu - IP_UDP_SIZE));
 770
 771         if (bootp == NULL)
 772                 return -1;
 773         *bootpm = bootp;
 774
 775         if (state->addr != NULL &&
 776             (type == DHCP_INFORM || type == DHCP_RELEASE ||
 777             (type == DHCP_REQUEST &&
 778             state->addr->mask.s_addr == lease->mask.s_addr &&
 779             (state->new == NULL || IS_DHCP(state->new)) &&
 780             !(state->added & STATE_FAKE))))
 781                 bootp->ciaddr = state->addr->addr.s_addr;
 782
 783         bootp->op = BOOTREQUEST;
 784         bootp->htype = (uint8_t)ifp->hwtype;
 785         if (ifp->hwlen != 0 && ifp->hwlen < sizeof(bootp->chaddr)) {
 786                 bootp->hlen = (uint8_t)ifp->hwlen;
 787                 memcpy(&bootp->chaddr, &ifp->hwaddr, ifp->hwlen);
 788         }
 789
 790         if (ifo->options & DHCPCD_BROADCAST &&
 791             bootp->ciaddr == 0 &&
 792             type != DHCP_DECLINE &&
 793             type != DHCP_RELEASE)
 794                 bootp->flags = htons(BROADCAST_FLAG);
 795
 796         if (type != DHCP_DECLINE && type != DHCP_RELEASE) {
 797                 struct timespec tv;
 798                 unsigned long long secs;
 799
 800                 clock_gettime(CLOCK_MONOTONIC, &tv);
 801                 secs = eloop_timespec_diff(&tv, &state->started, NULL);
 802                 if (secs > UINT16_MAX)
 803                         bootp->secs = htons((uint16_t)UINT16_MAX);
 804                 else
 805                         bootp->secs = htons((uint16_t)secs);
 806         }
 807
 808         bootp->xid = htonl(state->xid);
 809
 810         if (ifo->options & DHCPCD_BOOTP)
 811                 return sizeof(*bootp);
 812
 813         p = bootp->vend;
 814         e = (uint8_t *)bootp + (mtu - IP_UDP_SIZE) - 1; /* -1 for DHO_END */
 815
 816         ul = htonl(MAGIC_COOKIE);
 817         memcpy(p, &ul, sizeof(ul));
 818         p += sizeof(ul);
 819
 820 #define AREA_LEFT       (size_t)(e - p)
 821 #define AREA_FIT(s)     if ((s) > AREA_LEFT) goto toobig
 822 #define AREA_CHECK(s)   if ((s) + 2UL > AREA_LEFT) goto toobig
 823 #define PUT_ADDR(o, a)  do {            \
 824         AREA_CHECK(4);                  \
 825         *p++ = (o);                     \
 826         *p++ = 4;                       \
 827         memcpy(p, &(a)->s_addr, 4);     \
 828         p += 4;                         \
 829 } while (0 /* CONSTCOND */)
 830
 831         /* Options are listed in numerical order as per RFC 7844 Section 3.1
 832          * XXX: They should be randomised. */
 833
 834         bool putip = false;
 835         if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) {
 836                 if (type == DHCP_DECLINE ||
 837                     (type == DHCP_REQUEST &&
 838                     (state->addr == NULL ||
 839                     state->added & STATE_FAKE ||
 840                     lease->addr.s_addr != state->addr->addr.s_addr)))
 841                 {
 842                         putip = true;
 843                         PUT_ADDR(DHO_IPADDRESS, &lease->addr);
 844                 }
 845         }
 846
 847         AREA_CHECK(3);
 848         *p++ = DHO_MESSAGETYPE;
 849         *p++ = 1;
 850         *p++ = type;
 851
 852         if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) {
 853                 if (type == DHCP_RELEASE || putip) {
 854                         if (lease->server.s_addr)
 855                                 PUT_ADDR(DHO_SERVERID, &lease->server);
 856                 }
 857         }
 858
 859         if (type == DHCP_DECLINE) {
 860                 len = strlen(DAD);
 861                 if (len > AREA_LEFT) {
 862                         *p++ = DHO_MESSAGE;
 863                         *p++ = (uint8_t)len;
 864                         memcpy(p, DAD, len);
 865                         p += len;
 866                 }
 867         }
 868
 869 #define DHCP_DIR(type) ((type) == DHCP_DISCOVER || (type) == DHCP_INFORM || \
 870     (type) == DHCP_REQUEST)
 871
 872         if (DHCP_DIR(type)) {
 873                 /* vendor is already encoded correctly, so just add it */
 874                 if (ifo->vendor[0]) {
 875                         AREA_CHECK(ifo->vendor[0]);
 876                         *p++ = DHO_VENDOR;
 877                         memcpy(p, ifo->vendor, (size_t)ifo->vendor[0] + 1);
 878                         p += ifo->vendor[0] + 1;
 879                 }
 880         }
 881
 882         if (type == DHCP_DISCOVER && ifo->options & DHCPCD_REQUEST)
 883                 PUT_ADDR(DHO_IPADDRESS, &ifo->req_addr);
 884
 885         if (DHCP_DIR(type)) {
 886                 if (type != DHCP_INFORM) {
 887                         if (ifo->leasetime != 0) {
 888                                 AREA_CHECK(4);
 889                                 *p++ = DHO_LEASETIME;
 890                                 *p++ = 4;
 891                                 ul = htonl(ifo->leasetime);
 892                                 memcpy(p, &ul, 4);
 893                                 p += 4;
 894                         }
 895                 }
 896
 897                 AREA_CHECK(0);
 898                 *p++ = DHO_PARAMETERREQUESTLIST;
 899                 n_params = p;
 900                 *p++ = 0;
 901                 for (i = 0, opt = ifp->ctx->dhcp_opts;
 902                     i < ifp->ctx->dhcp_opts_len;
 903                     i++, opt++)
 904                 {
 905                         if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
 906                                 continue;
 907                         if (type == DHCP_INFORM &&
 908                             (opt->option == DHO_RENEWALTIME ||
 909                                 opt->option == DHO_REBINDTIME))
 910                                 continue;
 911                         AREA_FIT(1);
 912                         *p++ = (uint8_t)opt->option;
 913                 }
 914                 for (i = 0, opt = ifo->dhcp_override;
 915                     i < ifo->dhcp_override_len;
 916                     i++, opt++)
 917                 {
 918                         /* Check if added above */
 919                         for (lp = n_params + 1; lp < p; lp++)
 920                                 if (*lp == (uint8_t)opt->option)
 921                                         break;
 922                         if (lp < p)
 923                                 continue;
 924                         if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
 925                                 continue;
 926                         if (type == DHCP_INFORM &&
 927                             (opt->option == DHO_RENEWALTIME ||
 928                                 opt->option == DHO_REBINDTIME))
 929                                 continue;
 930                         AREA_FIT(1);
 931                         *p++ = (uint8_t)opt->option;
 932                 }
 933                 *n_params = (uint8_t)(p - n_params - 1);
 934
 935                 if (mtu != -1 &&
 936                     !(has_option_mask(ifo->nomask, DHO_MAXMESSAGESIZE)))
 937                 {
 938                         AREA_CHECK(2);
 939                         *p++ = DHO_MAXMESSAGESIZE;
 940                         *p++ = 2;
 941                         sz = htons((uint16_t)(mtu - IP_UDP_SIZE));
 942                         memcpy(p, &sz, 2);
 943                         p += 2;
 944                 }
 945
 946                 if (ifo->userclass[0] &&
 947                     !has_option_mask(ifo->nomask, DHO_USERCLASS))
 948                 {
 949                         AREA_CHECK(ifo->userclass[0]);
 950                         *p++ = DHO_USERCLASS;
 951                         memcpy(p, ifo->userclass,
 952                             (size_t)ifo->userclass[0] + 1);
 953                         p += ifo->userclass[0] + 1;
 954                 }
 955         }
 956
 957         if (state->clientid) {
 958                 AREA_CHECK(state->clientid[0]);
 959                 *p++ = DHO_CLIENTID;
 960                 memcpy(p, state->clientid, (size_t)state->clientid[0] + 1);
 961                 p += state->clientid[0] + 1;
 962         }
 963
 964         if (DHCP_DIR(type) &&
 965             !has_option_mask(ifo->nomask, DHO_VENDORCLASSID) &&
 966             ifo->vendorclassid[0])
 967         {
 968                 AREA_CHECK(ifo->vendorclassid[0]);
 969                 *p++ = DHO_VENDORCLASSID;
 970                 memcpy(p, ifo->vendorclassid, (size_t)ifo->vendorclassid[0]+1);
 971                 p += ifo->vendorclassid[0] + 1;
 972         }
 973
 974         if (type == DHCP_DISCOVER &&
 975             !(ifp->ctx->options & DHCPCD_TEST) &&
 976             DHC_REQ(ifo->requestmask, ifo->nomask, DHO_RAPIDCOMMIT))
 977         {
 978                 /* RFC 4039 Section 3 */
 979                 AREA_CHECK(0);
 980                 *p++ = DHO_RAPIDCOMMIT;
 981                 *p++ = 0;
 982         }
 983
 984         if (DHCP_DIR(type)) {
 985                 hostname = dhcp_get_hostname(hbuf, sizeof(hbuf), ifo);
 986
 987                 /*
 988                  * RFC4702 3.1 States that if we send the Client FQDN option
 989                  * then we MUST NOT also send the Host Name option.
 990                  * Technically we could, but that is not RFC conformant and
 991                  * also seems to break some DHCP server implemetations such as
 992                  * Windows. On the other hand, ISC dhcpd is just as non RFC
 993                  * conformant by not accepting a partially qualified FQDN.
 994                  */
 995                 if (ifo->fqdn != FQDN_DISABLE) {
 996                         /* IETF DHC-FQDN option (81), RFC4702 */
 997                         i = 3;
 998                         if (hostname)
 999                                 i += encode_rfc1035(hostname, NULL);
1000                         AREA_CHECK(i);
1001                         *p++ = DHO_FQDN;
1002                         *p++ = (uint8_t)i;
1003                         /*
1004                          * Flags: 0000NEOS
1005                          * S: 1 => Client requests Server to update
1006                          *         a RR in DNS as well as PTR
1007                          * O: 1 => Server indicates to client that
1008                          *         DNS has been updated
1009                          * E: 1 => Name data is DNS format
1010                          * N: 1 => Client requests Server to not
1011                          *         update DNS
1012                          */
1013                         if (hostname)
1014                                 *p++ = (uint8_t)((ifo->fqdn & 0x09) | 0x04);
1015                         else
1016                                 *p++ = (FQDN_NONE & 0x09) | 0x04;
1017                         *p++ = 0; /* from server for PTR RR */
1018                         *p++ = 0; /* from server for A RR if S=1 */
1019                         if (hostname) {
1020                                 i = encode_rfc1035(hostname, p);
1021                                 p += i;
1022                         }
1023                 } else if (ifo->options & DHCPCD_HOSTNAME && hostname) {
1024                         len = strlen(hostname);
1025                         AREA_CHECK(len);
1026                         *p++ = DHO_HOSTNAME;
1027                         *p++ = (uint8_t)len;
1028                         memcpy(p, hostname, len);
1029                         p += len;
1030                 }
1031         }
1032
1033 #ifdef AUTH
1034         auth = NULL;    /* appease GCC */
1035         auth_len = 0;
1036         if (ifo->auth.options & DHCPCD_AUTH_SEND) {
1037                 ssize_t alen = dhcp_auth_encode(ifp->ctx, &ifo->auth,
1038                     state->auth.token,
1039                     NULL, 0, 4, type, NULL, 0);
1040                 if (alen != -1 && alen > UINT8_MAX) {
1041                         errno = ERANGE;
1042                         alen = -1;
1043                 }
1044                 if (alen == -1)
1045                         logerr("%s: dhcp_auth_encode", ifp->name);
1046                 else if (alen != 0) {
1047                         auth_len = (uint8_t)alen;
1048                         AREA_CHECK(auth_len);
1049                         *p++ = DHO_AUTHENTICATION;
1050                         *p++ = auth_len;
1051                         auth = p;
1052                         p += auth_len;
1053                 }
1054         }
1055 #endif
1056
1057         /* RFC 2563 Auto Configure */
1058         if (type == DHCP_DISCOVER && ifo->options & DHCPCD_IPV4LL &&
1059             !(has_option_mask(ifo->nomask, DHO_AUTOCONFIGURE)))
1060         {
1061                 AREA_CHECK(1);
1062                 *p++ = DHO_AUTOCONFIGURE;
1063                 *p++ = 1;
1064                 *p++ = 1;
1065         }
1066
1067         if (DHCP_DIR(type)) {
1068                 if (ifo->mudurl[0]) {
1069                        AREA_CHECK(ifo->mudurl[0]);
1070                        *p++ = DHO_MUDURL;
1071                        memcpy(p, ifo->mudurl, (size_t)ifo->mudurl[0] + 1);
1072                        p += ifo->mudurl[0] + 1;
1073                 }
1074
1075                 if (ifo->vivco_len &&
1076                     !has_option_mask(ifo->nomask, DHO_VIVCO))
1077                 {
1078                         AREA_CHECK(sizeof(ul));
1079                         *p++ = DHO_VIVCO;
1080                         lp = p++;
1081                         *lp = sizeof(ul);
1082                         ul = htonl(ifo->vivco_en);
1083                         memcpy(p, &ul, sizeof(ul));
1084                         p += sizeof(ul);
1085                         for (i = 0, vivco = ifo->vivco;
1086                             i < ifo->vivco_len;
1087                             i++, vivco++)
1088                         {
1089                                 AREA_FIT(vivco->len);
1090                                 if (vivco->len + 2 + *lp > 255) {
1091                                         logerrx("%s: VIVCO option too big",
1092                                             ifp->name);
1093                                         free(bootp);
1094                                         return -1;
1095                                 }
1096                                 *p++ = (uint8_t)vivco->len;
1097                                 memcpy(p, vivco->data, vivco->len);
1098                                 p += vivco->len;
1099                                 *lp = (uint8_t)(*lp + vivco->len + 1);
1100                         }
1101                 }
1102
1103 #ifdef AUTH
1104                 if ((ifo->auth.options & DHCPCD_AUTH_SENDREQUIRE) !=
1105                     DHCPCD_AUTH_SENDREQUIRE &&
1106                     !has_option_mask(ifo->nomask, DHO_FORCERENEW_NONCE))
1107                 {
1108                         /* We support HMAC-MD5 */
1109                         AREA_CHECK(1);
1110                         *p++ = DHO_FORCERENEW_NONCE;
1111                         *p++ = 1;
1112                         *p++ = AUTH_ALG_HMAC_MD5;
1113                 }
1114 #endif
1115         }
1116
1117         *p++ = DHO_END;
1118         len = (size_t)(p - (uint8_t *)bootp);
1119
1120         /* Pad out to the BOOTP message length.
1121          * Even if we send a DHCP packet with a variable length vendor area,
1122          * some servers / relay agents don't like packets smaller than
1123          * a BOOTP message which is fine because that's stipulated
1124          * in RFC1542 section 2.1. */
1125         while (len < sizeof(*bootp)) {
1126                 *p++ = DHO_PAD;
1127                 len++;
1128         }
1129
1130 #ifdef AUTH
1131         if (ifo->auth.options & DHCPCD_AUTH_SEND && auth_len != 0)
1132                 dhcp_auth_encode(ifp->ctx, &ifo->auth, state->auth.token,
1133                     (uint8_t *)bootp, len, 4, type, auth, auth_len);
1134 #endif
1135
1136         return (ssize_t)len;
1137
1138 toobig:
1139         logerrx("%s: DHCP message too big", ifp->name);
1140         free(bootp);
1141         return -1;
1142 }
1143
1144 static size_t
1145 read_lease(struct interface *ifp, struct bootp **bootp)
1146 {
1147         union {
1148                 struct bootp bootp;
1149                 uint8_t buf[FRAMELEN_MAX];
1150         } buf;
1151         struct dhcp_state *state = D_STATE(ifp);
1152         ssize_t sbytes;
1153         size_t bytes;
1154         uint8_t type;
1155 #ifdef AUTH
1156         const uint8_t *auth;
1157         size_t auth_len;
1158 #endif
1159
1160         /* Safety */
1161         *bootp = NULL;
1162
1163         if (state->leasefile[0] == '\0') {
1164                 logdebugx("reading standard input");
1165                 sbytes = read(fileno(stdin), buf.buf, sizeof(buf.buf));
1166         } else {
1167                 logdebugx("%s: reading lease `%s'",
1168                     ifp->name, state->leasefile);
1169                 sbytes = dhcp_readfile(ifp->ctx, state->leasefile,
1170                     buf.buf, sizeof(buf.buf));
1171         }
1172         if (sbytes == -1) {
1173                 if (errno != ENOENT)
1174                         logerr("%s: %s", ifp->name, state->leasefile);
1175                 return 0;
1176         }
1177         bytes = (size_t)sbytes;
1178
1179         /* Ensure the packet is at lease BOOTP sized
1180          * with a vendor area of 4 octets
1181          * (it should be more, and our read packet enforces this so this
1182          * code should not be needed, but of course people could
1183          * scribble whatever in the stored lease file. */
1184         if (bytes < DHCP_MIN_LEN) {
1185                 logerrx("%s: %s: truncated lease", ifp->name, __func__);
1186                 return 0;
1187         }
1188
1189         if (ifp->ctx->options & DHCPCD_DUMPLEASE)
1190                 goto out;
1191
1192         /* We may have found a BOOTP server */
1193         if (get_option_uint8(ifp->ctx, &type, &buf.bootp, bytes,
1194             DHO_MESSAGETYPE) == -1)
1195                 type = 0;
1196
1197 #ifdef AUTH
1198         /* Authenticate the message */
1199         auth = get_option(ifp->ctx, &buf.bootp, bytes,
1200             DHO_AUTHENTICATION, &auth_len);
1201         if (auth) {
1202                 if (dhcp_auth_validate(&state->auth, &ifp->options->auth,
1203                     &buf.bootp, bytes, 4, type, auth, auth_len) == NULL)
1204                 {
1205                         logerr("%s: authentication failed", ifp->name);
1206                         return 0;
1207                 }
1208                 if (state->auth.token)
1209                         logdebugx("%s: validated using 0x%08" PRIu32,
1210                             ifp->name, state->auth.token->secretid);
1211                 else
1212                         logdebugx("%s: accepted reconfigure key", ifp->name);
1213         } else if ((ifp->options->auth.options & DHCPCD_AUTH_SENDREQUIRE) ==
1214             DHCPCD_AUTH_SENDREQUIRE)
1215         {
1216                 logerrx("%s: authentication now required", ifp->name);
1217                 return 0;
1218         }
1219 #endif
1220
1221 out:
1222         *bootp = malloc(bytes);
1223         if (*bootp == NULL) {
1224                 logerr(__func__);
1225                 return 0;
1226         }
1227         memcpy(*bootp, buf.buf, bytes);
1228         return bytes;
1229 }
1230
1231 static const struct dhcp_opt *
1232 dhcp_getoverride(const struct if_options *ifo, unsigned int o)
1233 {
1234         size_t i;
1235         const struct dhcp_opt *opt;
1236
1237         for (i = 0, opt = ifo->dhcp_override;
1238             i < ifo->dhcp_override_len;
1239             i++, opt++)
1240         {
1241                 if (opt->option == o)
1242                         return opt;
1243         }
1244         return NULL;
1245 }
1246
1247 static const uint8_t *
1248 dhcp_getoption(struct dhcpcd_ctx *ctx,
1249     size_t *os, unsigned int *code, size_t *len,
1250     const uint8_t *od, size_t ol, struct dhcp_opt **oopt)
1251 {
1252         size_t i;
1253         struct dhcp_opt *opt;
1254
1255         if (od) {
1256                 if (ol < 2) {
1257                         errno = EINVAL;
1258                         return NULL;
1259                 }
1260                 *os = 2; /* code + len */
1261                 *code = (unsigned int)*od++;
1262                 *len = (size_t)*od++;
1263                 if (*len > ol - *os) {
1264                         errno = ERANGE;
1265                         return NULL;
1266                 }
1267         }
1268
1269         *oopt = NULL;
1270         for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
1271                 if (opt->option == *code) {
1272                         *oopt = opt;
1273                         break;
1274                 }
1275         }
1276
1277         return od;
1278 }
1279
1280 ssize_t
1281 dhcp_env(FILE *fenv, const char *prefix, const struct interface *ifp,
1282     const struct bootp *bootp, size_t bootp_len)
1283 {
1284         const struct if_options *ifo;
1285         const uint8_t *p;
1286         struct in_addr addr;
1287         struct in_addr net;
1288         struct in_addr brd;
1289         struct dhcp_opt *opt, *vo;
1290         size_t i, pl;
1291         char safe[(BOOTP_FILE_LEN * 4) + 1];
1292         uint8_t overl = 0;
1293         uint32_t en;
1294
1295         ifo = ifp->options;
1296         if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len,
1297             DHO_OPTSOVERLOADED) == -1)
1298                 overl = 0;
1299
1300         if (bootp->yiaddr || bootp->ciaddr) {
1301                 /* Set some useful variables that we derive from the DHCP
1302                  * message but are not necessarily in the options */
1303                 addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr;
1304                 if (efprintf(fenv, "%s_ip_address=%s",
1305                     prefix, inet_ntoa(addr)) == -1)
1306                         return -1;
1307                 if (get_option_addr(ifp->ctx, &net,
1308                     bootp, bootp_len, DHO_SUBNETMASK) == -1) {
1309                         net.s_addr = ipv4_getnetmask(addr.s_addr);
1310                         if (efprintf(fenv, "%s_subnet_mask=%s",
1311                             prefix, inet_ntoa(net)) == -1)
1312                                 return -1;
1313                 }
1314                 if (efprintf(fenv, "%s_subnet_cidr=%d",
1315                     prefix, inet_ntocidr(net))== -1)
1316                         return -1;
1317                 if (get_option_addr(ifp->ctx, &brd,
1318                     bootp, bootp_len, DHO_BROADCAST) == -1)
1319                 {
1320                         brd.s_addr = addr.s_addr | ~net.s_addr;
1321                         if (efprintf(fenv, "%s_broadcast_address=%s",
1322                             prefix, inet_ntoa(brd)) == -1)
1323                                 return -1;
1324                 }
1325                 addr.s_addr = bootp->yiaddr & net.s_addr;
1326                 if (efprintf(fenv, "%s_network_number=%s",
1327                     prefix, inet_ntoa(addr)) == -1)
1328                         return -1;
1329         }
1330
1331         if (*bootp->file && !(overl & 1)) {
1332                 print_string(safe, sizeof(safe), OT_STRING,
1333                     bootp->file, sizeof(bootp->file));
1334                 if (efprintf(fenv, "%s_filename=%s", prefix, safe) == -1)
1335                         return -1;
1336         }
1337         if (*bootp->sname && !(overl & 2)) {
1338                 print_string(safe, sizeof(safe), OT_STRING | OT_DOMAIN,
1339                     bootp->sname, sizeof(bootp->sname));
1340                 if (efprintf(fenv, "%s_server_name=%s", prefix, safe) == -1)
1341                         return -1;
1342         }
1343
1344         /* Zero our indexes */
1345         for (i = 0, opt = ifp->ctx->dhcp_opts;
1346             i < ifp->ctx->dhcp_opts_len;
1347             i++, opt++)
1348                 dhcp_zero_index(opt);
1349         for (i = 0, opt = ifp->options->dhcp_override;
1350             i < ifp->options->dhcp_override_len;
1351             i++, opt++)
1352                 dhcp_zero_index(opt);
1353         for (i = 0, opt = ifp->ctx->vivso;
1354             i < ifp->ctx->vivso_len;
1355             i++, opt++)
1356                 dhcp_zero_index(opt);
1357
1358         for (i = 0, opt = ifp->ctx->dhcp_opts;
1359             i < ifp->ctx->dhcp_opts_len;
1360             i++, opt++)
1361         {
1362                 if (has_option_mask(ifo->nomask, opt->option))
1363                         continue;
1364                 if (dhcp_getoverride(ifo, opt->option))
1365                         continue;
1366                 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl);
1367                 if (p == NULL)
1368                         continue;
1369                 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1370                     opt, dhcp_getoption, p, pl);
1371
1372                 if (opt->option != DHO_VIVSO || pl <= (int)sizeof(uint32_t))
1373                         continue;
1374                 memcpy(&en, p, sizeof(en));
1375                 en = ntohl(en);
1376                 vo = vivso_find(en, ifp);
1377                 if (vo == NULL)
1378                         continue;
1379                 /* Skip over en + total size */
1380                 p += sizeof(en) + 1;
1381                 pl -= sizeof(en) + 1;
1382                 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1383                     vo, dhcp_getoption, p, pl);
1384         }
1385
1386         for (i = 0, opt = ifo->dhcp_override;
1387             i < ifo->dhcp_override_len;
1388             i++, opt++)
1389         {
1390                 if (has_option_mask(ifo->nomask, opt->option))
1391                         continue;
1392                 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl);
1393                 if (p == NULL)
1394                         continue;
1395                 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1396                     opt, dhcp_getoption, p, pl);
1397         }
1398
1399         return 1;
1400 }
1401
1402 static void
1403 get_lease(struct interface *ifp,
1404     struct dhcp_lease *lease, const struct bootp *bootp, size_t len)
1405 {
1406         struct dhcpcd_ctx *ctx;
1407
1408         assert(bootp != NULL);
1409
1410         memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie));
1411         /* BOOTP does not set yiaddr for replies when ciaddr is set. */
1412         lease->addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr;
1413         ctx = ifp->ctx;
1414         if (ifp->options->options & (DHCPCD_STATIC | DHCPCD_INFORM)) {
1415                 if (ifp->options->req_addr.s_addr != INADDR_ANY) {
1416                         lease->mask = ifp->options->req_mask;
1417                         if (ifp->options->req_brd.s_addr != INADDR_ANY)
1418                                 lease->brd = ifp->options->req_brd;
1419                         else
1420                                 lease->brd.s_addr =
1421                                     lease->addr.s_addr | ~lease->mask.s_addr;
1422                 } else {
1423                         const struct ipv4_addr *ia;
1424
1425                         ia = ipv4_iffindaddr(ifp, &lease->addr, NULL);
1426                         assert(ia != NULL);
1427                         lease->mask = ia->mask;
1428                         lease->brd = ia->brd;
1429                 }
1430         } else {
1431                 if (get_option_addr(ctx, &lease->mask, bootp, len,
1432                     DHO_SUBNETMASK) == -1)
1433                         lease->mask.s_addr =
1434                             ipv4_getnetmask(lease->addr.s_addr);
1435                 if (get_option_addr(ctx, &lease->brd, bootp, len,
1436                     DHO_BROADCAST) == -1)
1437                         lease->brd.s_addr =
1438                             lease->addr.s_addr | ~lease->mask.s_addr;
1439         }
1440         if (get_option_uint32(ctx, &lease->leasetime,
1441             bootp, len, DHO_LEASETIME) != 0)
1442                 lease->leasetime = DHCP_INFINITE_LIFETIME;
1443         if (get_option_uint32(ctx, &lease->renewaltime,
1444             bootp, len, DHO_RENEWALTIME) != 0)
1445                 lease->renewaltime = 0;
1446         if (get_option_uint32(ctx, &lease->rebindtime,
1447             bootp, len, DHO_REBINDTIME) != 0)
1448                 lease->rebindtime = 0;
1449         if (get_option_addr(ctx, &lease->server, bootp, len, DHO_SERVERID) != 0)
1450                 lease->server.s_addr = INADDR_ANY;
1451 }
1452
1453 static const char *
1454 get_dhcp_op(uint8_t type)
1455 {
1456         const struct dhcp_op *d;
1457
1458         for (d = dhcp_ops; d->name; d++)
1459                 if (d->value == type)
1460                         return d->name;
1461         return NULL;
1462 }
1463
1464 static void
1465 dhcp_fallback(void *arg)
1466 {
1467         struct interface *iface;
1468
1469         iface = (struct interface *)arg;
1470         dhcpcd_selectprofile(iface, iface->options->fallback);
1471         dhcpcd_startinterface(iface);
1472 }
1473
1474 static void
1475 dhcp_new_xid(struct interface *ifp)
1476 {
1477         struct dhcp_state *state;
1478         const struct interface *ifp1;
1479         const struct dhcp_state *state1;
1480
1481         state = D_STATE(ifp);
1482         if (ifp->options->options & DHCPCD_XID_HWADDR &&
1483             ifp->hwlen >= sizeof(state->xid))
1484                 /* The lower bits are probably more unique on the network */
1485                 memcpy(&state->xid,
1486                     (ifp->hwaddr + ifp->hwlen) - sizeof(state->xid),
1487                     sizeof(state->xid));
1488         else {
1489 again:
1490                 state->xid = arc4random();
1491         }
1492
1493         /* Ensure it's unique */
1494         TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) {
1495                 if (ifp == ifp1)
1496                         continue;
1497                 if ((state1 = D_CSTATE(ifp1)) == NULL)
1498                         continue;
1499                 if (state1->xid == state->xid)
1500                         break;
1501         }
1502         if (ifp1 != NULL) {
1503                 if (ifp->options->options & DHCPCD_XID_HWADDR &&
1504                     ifp->hwlen >= sizeof(state->xid))
1505                 {
1506                         logerrx("%s: duplicate xid on %s",
1507                             ifp->name, ifp1->name);
1508                             return;
1509                 }
1510                 goto again;
1511         }
1512
1513         /* We can't do this when sharing leases across interfaes */
1514 #if 0
1515         /* As the XID changes, re-apply the filter. */
1516         if (state->bpf_fd != -1) {
1517                 if (bpf_bootp(ifp, state->bpf_fd) == -1)
1518                         logerr(__func__); /* try to continue */
1519         }
1520 #endif
1521 }
1522
1523 void
1524 dhcp_close(struct interface *ifp)
1525 {
1526         struct dhcpcd_ctx *ctx = ifp->ctx;
1527         struct dhcp_state *state = D_STATE(ifp);
1528
1529         if (state == NULL)
1530                 return;
1531
1532 #ifdef PRIVSEP
1533         if (IN_PRIVSEP_SE(ctx)) {
1534                 ps_bpf_closebootp(ifp);
1535                 if (state->addr != NULL)
1536                         ps_inet_closebootp(state->addr);
1537         }
1538 #endif
1539
1540         if (state->bpf != NULL) {
1541                 eloop_event_delete(ctx->eloop, state->bpf->bpf_fd);
1542                 bpf_close(state->bpf);
1543                 state->bpf = NULL;
1544         }
1545         if (state->udp_rfd != -1) {
1546                 eloop_event_delete(ctx->eloop, state->udp_rfd);
1547                 close(state->udp_rfd);
1548                 state->udp_rfd = -1;
1549         }
1550
1551         state->interval = 0;
1552 }
1553
1554 int
1555 dhcp_openudp(struct in_addr *ia)
1556 {
1557         int s;
1558         struct sockaddr_in sin;
1559         int n;
1560
1561         if ((s = xsocket(PF_INET, SOCK_DGRAM | SOCK_CXNB, IPPROTO_UDP)) == -1)
1562                 return -1;
1563
1564         n = 1;
1565         if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &n, sizeof(n)) == -1)
1566                 goto errexit;
1567 #ifdef IP_RECVIF
1568         if (setsockopt(s, IPPROTO_IP, IP_RECVIF, &n, sizeof(n)) == -1)
1569                 goto errexit;
1570 #else
1571         if (setsockopt(s, IPPROTO_IP, IP_RECVPKTINFO, &n, sizeof(n)) == -1)
1572                 goto errexit;
1573 #endif
1574 #ifdef SO_RERROR
1575         if (setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)) == -1)
1576                 goto errexit;
1577 #endif
1578
1579         memset(&sin, 0, sizeof(sin));
1580         sin.sin_family = AF_INET;
1581         sin.sin_port = htons(BOOTPC);
1582         if (ia != NULL)
1583                 sin.sin_addr = *ia;
1584         if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) == -1)
1585                 goto errexit;
1586
1587         return s;
1588
1589 errexit:
1590         close(s);
1591         return -1;
1592 }
1593
1594 static uint16_t
1595 in_cksum(const void *data, size_t len, uint32_t *isum)
1596 {
1597         const uint16_t *word = data;
1598         uint32_t sum = isum != NULL ? *isum : 0;
1599
1600         for (; len > 1; len -= sizeof(*word))
1601                 sum += *word++;
1602
1603         if (len == 1)
1604                 sum += htons((uint16_t)(*(const uint8_t *)word << 8));
1605
1606         if (isum != NULL)
1607                 *isum = sum;
1608
1609         sum = (sum >> 16) + (sum & 0xffff);
1610         sum += (sum >> 16);
1611
1612         return (uint16_t)~sum;
1613 }
1614
1615 static struct bootp_pkt *
1616 dhcp_makeudppacket(size_t *sz, const uint8_t *data, size_t length,
1617         struct in_addr source, struct in_addr dest)
1618 {
1619         struct bootp_pkt *udpp;
1620         struct ip *ip;
1621         struct udphdr *udp;
1622
1623         if ((udpp = calloc(1, sizeof(*ip) + sizeof(*udp) + length)) == NULL)
1624                 return NULL;
1625         ip = &udpp->ip;
1626         udp = &udpp->udp;
1627
1628         /* OK, this is important :)
1629          * We copy the data to our packet and then create a small part of the
1630          * ip structure and an invalid ip_len (basically udp length).
1631          * We then fill the udp structure and put the checksum
1632          * of the whole packet into the udp checksum.
1633          * Finally we complete the ip structure and ip checksum.
1634          * If we don't do the ordering like so then the udp checksum will be
1635          * broken, so find another way of doing it! */
1636
1637         memcpy(&udpp->bootp, data, length);
1638
1639         ip->ip_p = IPPROTO_UDP;
1640         ip->ip_src.s_addr = source.s_addr;
1641         if (dest.s_addr == 0)
1642                 ip->ip_dst.s_addr = INADDR_BROADCAST;
1643         else
1644                 ip->ip_dst.s_addr = dest.s_addr;
1645
1646         udp->uh_sport = htons(BOOTPC);
1647         udp->uh_dport = htons(BOOTPS);
1648         udp->uh_ulen = htons((uint16_t)(sizeof(*udp) + length));
1649         ip->ip_len = udp->uh_ulen;
1650         udp->uh_sum = in_cksum(udpp, sizeof(*ip) + sizeof(*udp) + length, NULL);
1651
1652         ip->ip_v = IPVERSION;
1653         ip->ip_hl = sizeof(*ip) >> 2;
1654         ip->ip_id = (uint16_t)arc4random_uniform(UINT16_MAX);
1655         ip->ip_ttl = IPDEFTTL;
1656         ip->ip_len = htons((uint16_t)(sizeof(*ip) + sizeof(*udp) + length));
1657         ip->ip_sum = in_cksum(ip, sizeof(*ip), NULL);
1658         if (ip->ip_sum == 0)
1659                 ip->ip_sum = 0xffff; /* RFC 768 */
1660
1661         *sz = sizeof(*ip) + sizeof(*udp) + length;
1662         return udpp;
1663 }
1664
1665 static ssize_t
1666 dhcp_sendudp(struct interface *ifp, struct in_addr *to, void *data, size_t len)
1667 {
1668         struct sockaddr_in sin = {
1669                 .sin_family = AF_INET,
1670                 .sin_addr = *to,
1671                 .sin_port = htons(BOOTPS),
1672 #ifdef HAVE_SA_LEN
1673                 .sin_len = sizeof(sin),
1674 #endif
1675         };
1676         struct udphdr udp = {
1677             .uh_sport = htons(BOOTPC),
1678             .uh_dport = htons(BOOTPS),
1679             .uh_ulen = htons((uint16_t)(sizeof(udp) + len)),
1680         };
1681         struct iovec iov[] = {
1682             { .iov_base = &udp, .iov_len = sizeof(udp), },
1683             { .iov_base = data, .iov_len = len, },
1684         };
1685         struct msghdr msg = {
1686                 .msg_name = (void *)&sin,
1687                 .msg_namelen = sizeof(sin),
1688                 .msg_iov = iov,
1689                 .msg_iovlen = __arraycount(iov),
1690         };
1691         struct dhcpcd_ctx *ctx = ifp->ctx;
1692
1693 #ifdef PRIVSEP
1694         if (ctx->options & DHCPCD_PRIVSEP)
1695                 return ps_inet_sendbootp(ifp, &msg);
1696 #endif
1697         return sendmsg(ctx->udp_wfd, &msg, 0);
1698 }
1699
1700 static void
1701 send_message(struct interface *ifp, uint8_t type,
1702     void (*callback)(void *))
1703 {
1704         struct dhcp_state *state = D_STATE(ifp);
1705         struct if_options *ifo = ifp->options;
1706         struct bootp *bootp;
1707         struct bootp_pkt *udp;
1708         size_t len, ulen;
1709         ssize_t r;
1710         struct in_addr from, to;
1711         unsigned int RT;
1712
1713         if (callback == NULL) {
1714                 /* No carrier? Don't bother sending the packet. */
1715                 if (ifp->carrier <= LINK_DOWN)
1716                         return;
1717                 logdebugx("%s: sending %s with xid 0x%x",
1718                     ifp->name,
1719                     ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
1720                     state->xid);
1721                 RT = 0; /* bogus gcc warning */
1722         } else {
1723                 if (state->interval == 0)
1724                         state->interval = 4;
1725                 else {
1726                         state->interval *= 2;
1727                         if (state->interval > 64)
1728                                 state->interval = 64;
1729                 }
1730                 RT = (state->interval * MSEC_PER_SEC) +
1731                     (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC);
1732                 /* No carrier? Don't bother sending the packet.
1733                  * However, we do need to advance the timeout. */
1734                 if (ifp->carrier <= LINK_DOWN)
1735                         goto fail;
1736                 logdebugx("%s: sending %s (xid 0x%x), next in %0.1f seconds",
1737                     ifp->name,
1738                     ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
1739                     state->xid,
1740                     (float)RT / MSEC_PER_SEC);
1741         }
1742
1743         r = make_message(&bootp, ifp, type);
1744         if (r == -1)
1745                 goto fail;
1746         len = (size_t)r;
1747
1748         if (!(state->added & STATE_FAKE) &&
1749             state->addr != NULL &&
1750             ipv4_iffindaddr(ifp, &state->lease.addr, NULL) != NULL)
1751                 from.s_addr = state->lease.addr.s_addr;
1752         else
1753                 from.s_addr = INADDR_ANY;
1754         if (from.s_addr != INADDR_ANY &&
1755             state->lease.server.s_addr != INADDR_ANY)
1756                 to.s_addr = state->lease.server.s_addr;
1757         else
1758                 to.s_addr = INADDR_BROADCAST;
1759
1760         /*
1761          * If not listening on the unspecified address we can
1762          * only receive broadcast messages via BPF.
1763          * Sockets bound to an address cannot receive broadcast messages
1764          * even if they are setup to send them.
1765          * Broadcasting from UDP is only an optimisation for rebinding
1766          * and on BSD, at least, is reliant on the subnet route being
1767          * correctly configured to receive the unicast reply.
1768          * As such, we always broadcast and receive the reply to it via BPF.
1769          * This also guarantees we have a DHCP server attached to the
1770          * interface we want to configure because we can't dictate the
1771          * interface via IP_PKTINFO unlike for IPv6.
1772          */
1773         if (to.s_addr != INADDR_BROADCAST) {
1774                 if (dhcp_sendudp(ifp, &to, bootp, len) != -1)
1775                         goto out;
1776                 logerr("%s: dhcp_sendudp", ifp->name);
1777         }
1778
1779         if (dhcp_openbpf(ifp) == -1)
1780                 goto out;
1781
1782         udp = dhcp_makeudppacket(&ulen, (uint8_t *)bootp, len, from, to);
1783         if (udp == NULL) {
1784                 logerr("%s: dhcp_makeudppacket", ifp->name);
1785                 r = 0;
1786 #ifdef PRIVSEP
1787         } else if (ifp->ctx->options & DHCPCD_PRIVSEP) {
1788                 r = ps_bpf_sendbootp(ifp, udp, ulen);
1789                 free(udp);
1790 #endif
1791         } else {
1792                 r = bpf_send(state->bpf, ETHERTYPE_IP, udp, ulen);
1793                 free(udp);
1794         }
1795         /* If we failed to send a raw packet this normally means
1796          * we don't have the ability to work beneath the IP layer
1797          * for this interface.
1798          * As such we remove it from consideration without actually
1799          * stopping the interface. */
1800         if (r == -1) {
1801                 logerr("%s: bpf_send", ifp->name);
1802                 switch(errno) {
1803                 case ENETDOWN:
1804                 case ENETRESET:
1805                 case ENETUNREACH:
1806                 case ENOBUFS:
1807                         break;
1808                 default:
1809                         if (!(ifp->ctx->options & DHCPCD_TEST))
1810                                 dhcp_drop(ifp, "FAIL");
1811                         eloop_timeout_delete(ifp->ctx->eloop,
1812                             NULL, ifp);
1813                         callback = NULL;
1814                 }
1815         }
1816
1817 out:
1818         free(bootp);
1819
1820 fail:
1821         /* Even if we fail to send a packet we should continue as we are
1822          * as our failure timeouts will change out codepath when needed. */
1823         if (callback != NULL)
1824                 eloop_timeout_add_msec(ifp->ctx->eloop, RT, callback, ifp);
1825 }
1826
1827 static void
1828 send_inform(void *arg)
1829 {
1830
1831         send_message((struct interface *)arg, DHCP_INFORM, send_inform);
1832 }
1833
1834 static void
1835 send_discover(void *arg)
1836 {
1837
1838         send_message((struct interface *)arg, DHCP_DISCOVER, send_discover);
1839 }
1840
1841 static void
1842 send_request(void *arg)
1843 {
1844
1845         send_message((struct interface *)arg, DHCP_REQUEST, send_request);
1846 }
1847
1848 static void
1849 send_renew(void *arg)
1850 {
1851
1852         send_message((struct interface *)arg, DHCP_REQUEST, send_renew);
1853 }
1854
1855 static void
1856 send_rebind(void *arg)
1857 {
1858
1859         send_message((struct interface *)arg, DHCP_REQUEST, send_rebind);
1860 }
1861
1862 void
1863 dhcp_discover(void *arg)
1864 {
1865         struct interface *ifp = arg;
1866         struct dhcp_state *state = D_STATE(ifp);
1867         struct if_options *ifo = ifp->options;
1868
1869         state->state = DHS_DISCOVER;
1870         dhcp_new_xid(ifp);
1871         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
1872         if (ifo->fallback)
1873                 eloop_timeout_add_sec(ifp->ctx->eloop,
1874                     ifo->reboot, dhcp_fallback, ifp);
1875 #ifdef IPV4LL
1876         else if (ifo->options & DHCPCD_IPV4LL)
1877                 eloop_timeout_add_sec(ifp->ctx->eloop,
1878                     ifo->reboot, ipv4ll_start, ifp);
1879 #endif
1880         if (ifo->options & DHCPCD_REQUEST)
1881                 loginfox("%s: soliciting a DHCP lease (requesting %s)",
1882                     ifp->name, inet_ntoa(ifo->req_addr));
1883         else
1884                 loginfox("%s: soliciting a %s lease",
1885                     ifp->name, ifo->options & DHCPCD_BOOTP ? "BOOTP" : "DHCP");
1886         send_discover(ifp);
1887 }
1888
1889 static void
1890 dhcp_request(void *arg)
1891 {
1892         struct interface *ifp = arg;
1893         struct dhcp_state *state = D_STATE(ifp);
1894
1895         state->state = DHS_REQUEST;
1896         send_request(ifp);
1897 }
1898
1899 static void
1900 dhcp_expire1(struct interface *ifp)
1901 {
1902         struct dhcp_state *state = D_STATE(ifp);
1903
1904         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
1905         dhcp_drop(ifp, "EXPIRE");
1906         dhcp_unlink(ifp->ctx, state->leasefile);
1907         state->interval = 0;
1908         if (!(ifp->options->options & DHCPCD_LINK) || ifp->carrier > LINK_DOWN)
1909                 dhcp_discover(ifp);
1910 }
1911
1912 static void
1913 dhcp_expire(void *arg)
1914 {
1915         struct interface *ifp = arg;
1916
1917         if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) {
1918                 logwarnx("%s: DHCP lease expired, extending lease", ifp->name);
1919                 return;
1920         }
1921
1922         logerrx("%s: DHCP lease expired", ifp->name);
1923         dhcp_expire1(ifp);
1924 }
1925
1926 #if defined(ARP) || defined(IN_IFF_DUPLICATED)
1927 static void
1928 dhcp_decline(struct interface *ifp)
1929 {
1930
1931         send_message(ifp, DHCP_DECLINE, NULL);
1932 }
1933 #endif
1934
1935 static void
1936 dhcp_startrenew(void *arg)
1937 {
1938         struct interface *ifp = arg;
1939         struct dhcp_state *state;
1940         struct dhcp_lease *lease;
1941
1942         if ((state = D_STATE(ifp)) == NULL)
1943                 return;
1944
1945         /* Only renew in the bound or renew states */
1946         if (state->state != DHS_BOUND &&
1947             state->state != DHS_RENEW)
1948                 return;
1949
1950         /* Remove the timeout as the renew may have been forced. */
1951         eloop_timeout_delete(ifp->ctx->eloop, dhcp_startrenew, ifp);
1952
1953         lease = &state->lease;
1954         logdebugx("%s: renewing lease of %s", ifp->name,
1955             inet_ntoa(lease->addr));
1956         state->state = DHS_RENEW;
1957         dhcp_new_xid(ifp);
1958         state->interval = 0;
1959         send_renew(ifp);
1960 }
1961
1962 void
1963 dhcp_renew(struct interface *ifp)
1964 {
1965
1966         dhcp_startrenew(ifp);
1967 }
1968
1969 static void
1970 dhcp_rebind(void *arg)
1971 {
1972         struct interface *ifp = arg;
1973         struct dhcp_state *state = D_STATE(ifp);
1974         struct dhcp_lease *lease = &state->lease;
1975
1976         logwarnx("%s: failed to renew DHCP, rebinding", ifp->name);
1977         logdebugx("%s: expire in %"PRIu32" seconds",
1978             ifp->name, lease->leasetime - lease->rebindtime);
1979         state->state = DHS_REBIND;
1980         eloop_timeout_delete(ifp->ctx->eloop, send_renew, ifp);
1981         state->lease.server.s_addr = INADDR_ANY;
1982         state->interval = 0;
1983         ifp->options->options &= ~(DHCPCD_CSR_WARNED |
1984             DHCPCD_ROUTER_HOST_ROUTE_WARNED);
1985         send_rebind(ifp);
1986 }
1987
1988 #if defined(ARP) || defined(IN_IFF_DUPLICATED)
1989 static void
1990 dhcp_finish_dad(struct interface *ifp, struct in_addr *ia)
1991 {
1992         struct dhcp_state *state = D_STATE(ifp);
1993
1994         if (state->state != DHS_PROBE)
1995                 return;
1996         if (state->offer == NULL || state->offer->yiaddr != ia->s_addr)
1997                 return;
1998
1999         logdebugx("%s: DAD completed for %s", ifp->name, inet_ntoa(*ia));
2000         if (!(ifp->options->options & DHCPCD_INFORM))
2001                 dhcp_bind(ifp);
2002 #ifndef IN_IFF_DUPLICATED
2003         else {
2004                 struct bootp *bootp;
2005                 size_t len;
2006
2007                 bootp = state->new;
2008                 len = state->new_len;
2009                 state->new = state->offer;
2010                 state->new_len = state->offer_len;
2011                 get_lease(ifp, &state->lease, state->new, state->new_len);
2012                 ipv4_applyaddr(ifp);
2013                 state->new = bootp;
2014                 state->new_len = len;
2015         }
2016 #endif
2017
2018 #ifdef IPV4LL
2019         /* Stop IPv4LL now we have a working DHCP address */
2020         ipv4ll_drop(ifp);
2021 #endif
2022
2023         if (ifp->options->options & DHCPCD_INFORM)
2024                 dhcp_inform(ifp);
2025 }
2026
2027
2028 static bool
2029 dhcp_addr_duplicated(struct interface *ifp, struct in_addr *ia)
2030 {
2031         struct dhcp_state *state = D_STATE(ifp);
2032         unsigned long long opts = ifp->options->options;
2033         struct dhcpcd_ctx *ctx = ifp->ctx;
2034         bool deleted = false;
2035 #ifdef IN_IFF_DUPLICATED
2036         struct ipv4_addr *iap;
2037 #endif
2038
2039         if ((state->offer == NULL || state->offer->yiaddr != ia->s_addr) &&
2040             !IN_ARE_ADDR_EQUAL(ia, &state->lease.addr))
2041                 return deleted;
2042
2043         /* RFC 2131 3.1.5, Client-server interaction */
2044         logerrx("%s: DAD detected %s", ifp->name, inet_ntoa(*ia));
2045         dhcp_unlink(ifp->ctx, state->leasefile);
2046         if (!(opts & DHCPCD_STATIC) && !state->lease.frominfo)
2047                 dhcp_decline(ifp);
2048 #ifdef IN_IFF_DUPLICATED
2049         if ((iap = ipv4_iffindaddr(ifp, ia, NULL)) != NULL) {
2050                 ipv4_deladdr(iap, 0);
2051                 deleted = true;
2052         }
2053 #endif
2054         eloop_timeout_delete(ctx->eloop, NULL, ifp);
2055         if (opts & (DHCPCD_STATIC | DHCPCD_INFORM)) {
2056                 state->reason = "EXPIRE";
2057                 script_runreason(ifp, state->reason);
2058 #define NOT_ONLY_SELF (DHCPCD_MASTER | DHCPCD_IPV6RS | DHCPCD_DHCP6)
2059                 if (!(ctx->options & NOT_ONLY_SELF))
2060                         eloop_exit(ifp->ctx->eloop, EXIT_FAILURE);
2061                 return deleted;
2062         }
2063         eloop_timeout_add_sec(ifp->ctx->eloop,
2064             DHCP_RAND_MAX, dhcp_discover, ifp);
2065         return deleted;
2066 }
2067 #endif
2068
2069 #ifdef ARP
2070 #ifdef KERNEL_RFC5227
2071 static void
2072 dhcp_arp_announced(struct arp_state *state)
2073 {
2074
2075         arp_free(state);
2076 }
2077 #else
2078 static void
2079 dhcp_arp_defend_failed(struct arp_state *astate)
2080 {
2081         struct interface *ifp = astate->iface;
2082
2083         dhcp_drop(ifp, "EXPIRED");
2084         dhcp_start1(ifp);
2085 }
2086 #endif
2087
2088 #if !defined(KERNEL_RFC5227) || defined(ARPING)
2089 static void dhcp_arp_not_found(struct arp_state *);
2090
2091 static struct arp_state *
2092 dhcp_arp_new(struct interface *ifp, struct in_addr *addr)
2093 {
2094         struct arp_state *astate;
2095
2096         astate = arp_new(ifp, addr);
2097         if (astate == NULL)
2098                 return NULL;
2099
2100         astate->found_cb = dhcp_arp_found;
2101         astate->not_found_cb = dhcp_arp_not_found;
2102 #ifdef KERNEL_RFC5227
2103         astate->announced_cb = dhcp_arp_announced;
2104 #else
2105         astate->announced_cb = NULL;
2106         astate->defend_failed_cb = dhcp_arp_defend_failed;
2107 #endif
2108         return astate;
2109 }
2110 #endif
2111
2112 #ifdef ARPING
2113 static int
2114 dhcp_arping(struct interface *ifp)
2115 {
2116         struct dhcp_state *state;
2117         struct if_options *ifo;
2118         struct arp_state *astate;
2119         struct in_addr addr;
2120
2121         state = D_STATE(ifp);
2122         ifo = ifp->options;
2123
2124         if (ifo->arping_len == 0 || state->arping_index > ifo->arping_len)
2125                 return 0;
2126
2127         if (state->arping_index + 1 == ifo->arping_len) {
2128                 state->arping_index++;
2129                 dhcpcd_startinterface(ifp);
2130                 return 1;
2131         }
2132
2133         addr.s_addr = ifo->arping[++state->arping_index];
2134         astate = dhcp_arp_new(ifp, &addr);
2135         if (astate == NULL) {
2136                 logerr(__func__);
2137                 return -1;
2138         }
2139         arp_probe(astate);
2140         return 1;
2141 }
2142 #endif
2143
2144 #if !defined(KERNEL_RFC5227) || defined(ARPING)
2145 static void
2146 dhcp_arp_not_found(struct arp_state *astate)
2147 {
2148         struct interface *ifp;
2149
2150         ifp = astate->iface;
2151 #ifdef ARPING
2152         if (dhcp_arping(ifp) == 1) {
2153                 arp_free(astate);
2154                 return;
2155         }
2156 #endif
2157
2158         dhcp_finish_dad(ifp, &astate->addr);
2159 }
2160
2161 static void
2162 dhcp_arp_found(struct arp_state *astate, const struct arp_msg *amsg)
2163 {
2164         struct in_addr addr;
2165         struct interface *ifp = astate->iface;
2166 #ifdef ARPING
2167         struct dhcp_state *state;
2168         struct if_options *ifo;
2169
2170         state = D_STATE(ifp);
2171
2172         ifo = ifp->options;
2173         if (state->arping_index != -1 &&
2174             state->arping_index < ifo->arping_len &&
2175             amsg &&
2176             amsg->sip.s_addr == ifo->arping[state->arping_index])
2177         {
2178                 char buf[HWADDR_LEN * 3];
2179
2180                 hwaddr_ntoa(amsg->sha, ifp->hwlen, buf, sizeof(buf));
2181                 if (dhcpcd_selectprofile(ifp, buf) == -1 &&
2182                     dhcpcd_selectprofile(ifp, inet_ntoa(amsg->sip)) == -1)
2183                 {
2184                         /* We didn't find a profile for this
2185                          * address or hwaddr, so move to the next
2186                          * arping profile */
2187                         dhcp_arp_not_found(astate);
2188                         return;
2189                 }
2190                 arp_free(astate);
2191                 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2192                 dhcpcd_startinterface(ifp);
2193                 return;
2194         }
2195 #else
2196         UNUSED(amsg);
2197 #endif
2198
2199         addr = astate->addr;
2200         arp_free(astate);
2201         dhcp_addr_duplicated(ifp, &addr);
2202 }
2203 #endif
2204
2205 #endif /* ARP */
2206
2207 void
2208 dhcp_bind(struct interface *ifp)
2209 {
2210         struct dhcpcd_ctx *ctx = ifp->ctx;
2211         struct dhcp_state *state = D_STATE(ifp);
2212         struct if_options *ifo = ifp->options;
2213         struct dhcp_lease *lease = &state->lease;
2214         uint8_t old_state;
2215
2216         state->reason = NULL;
2217         /* If we don't have an offer, we are re-binding a lease on preference,
2218          * normally when two interfaces have a lease matching IP addresses. */
2219         if (state->offer) {
2220                 free(state->old);
2221                 state->old = state->new;
2222                 state->old_len = state->new_len;
2223                 state->new = state->offer;
2224                 state->new_len = state->offer_len;
2225                 state->offer = NULL;
2226                 state->offer_len = 0;
2227         }
2228         get_lease(ifp, lease, state->new, state->new_len);
2229         if (ifo->options & DHCPCD_STATIC) {
2230                 loginfox("%s: using static address %s/%d",
2231                     ifp->name, inet_ntoa(lease->addr),
2232                     inet_ntocidr(lease->mask));
2233                 lease->leasetime = DHCP_INFINITE_LIFETIME;
2234                 state->reason = "STATIC";
2235         } else if (ifo->options & DHCPCD_INFORM) {
2236                 loginfox("%s: received approval for %s",
2237                     ifp->name, inet_ntoa(lease->addr));
2238                 lease->leasetime = DHCP_INFINITE_LIFETIME;
2239                 state->reason = "INFORM";
2240         } else {
2241                 if (lease->frominfo)
2242                         state->reason = "TIMEOUT";
2243                 if (lease->leasetime == DHCP_INFINITE_LIFETIME) {
2244                         lease->renewaltime =
2245                             lease->rebindtime =
2246                             lease->leasetime;
2247                         loginfox("%s: leased %s for infinity",
2248                            ifp->name, inet_ntoa(lease->addr));
2249                 } else {
2250                         if (lease->leasetime < DHCP_MIN_LEASE) {
2251                                 logwarnx("%s: minimum lease is %d seconds",
2252                                     ifp->name, DHCP_MIN_LEASE);
2253                                 lease->leasetime = DHCP_MIN_LEASE;
2254                         }
2255                         if (lease->rebindtime == 0)
2256                                 lease->rebindtime =
2257                                     (uint32_t)(lease->leasetime * T2);
2258                         else if (lease->rebindtime >= lease->leasetime) {
2259                                 lease->rebindtime =
2260                                     (uint32_t)(lease->leasetime * T2);
2261                                 logwarnx("%s: rebind time greater than lease "
2262                                     "time, forcing to %"PRIu32" seconds",
2263                                     ifp->name, lease->rebindtime);
2264                         }
2265                         if (lease->renewaltime == 0)
2266                                 lease->renewaltime =
2267                                     (uint32_t)(lease->leasetime * T1);
2268                         else if (lease->renewaltime > lease->rebindtime) {
2269                                 lease->renewaltime =
2270                                     (uint32_t)(lease->leasetime * T1);
2271                                 logwarnx("%s: renewal time greater than "
2272                                     "rebind time, forcing to %"PRIu32" seconds",
2273                                     ifp->name, lease->renewaltime);
2274                         }
2275                         if (state->state == DHS_RENEW && state->addr &&
2276                             lease->addr.s_addr == state->addr->addr.s_addr &&
2277                             !(state->added & STATE_FAKE))
2278                                 logdebugx("%s: leased %s for %"PRIu32" seconds",
2279                                     ifp->name, inet_ntoa(lease->addr),
2280                                     lease->leasetime);
2281                         else
2282                                 loginfox("%s: leased %s for %"PRIu32" seconds",
2283                                     ifp->name, inet_ntoa(lease->addr),
2284                                     lease->leasetime);
2285                 }
2286         }
2287         if (ctx->options & DHCPCD_TEST) {
2288                 state->reason = "TEST";
2289                 script_runreason(ifp, state->reason);
2290                 eloop_exit(ctx->eloop, EXIT_SUCCESS);
2291                 return;
2292         }
2293         if (state->reason == NULL) {
2294                 if (state->old && !(state->added & STATE_FAKE)) {
2295                         if (state->old->yiaddr == state->new->yiaddr &&
2296                             lease->server.s_addr &&
2297                             state->state != DHS_REBIND)
2298                                 state->reason = "RENEW";
2299                         else
2300                                 state->reason = "REBIND";
2301                 } else if (state->state == DHS_REBOOT)
2302                         state->reason = "REBOOT";
2303                 else
2304                         state->reason = "BOUND";
2305         }
2306         if (lease->leasetime == DHCP_INFINITE_LIFETIME)
2307                 lease->renewaltime = lease->rebindtime = lease->leasetime;
2308         else {
2309                 eloop_timeout_add_sec(ctx->eloop,
2310                     lease->renewaltime, dhcp_startrenew, ifp);
2311                 eloop_timeout_add_sec(ctx->eloop,
2312                     lease->rebindtime, dhcp_rebind, ifp);
2313                 eloop_timeout_add_sec(ctx->eloop,
2314                     lease->leasetime, dhcp_expire, ifp);
2315                 logdebugx("%s: renew in %"PRIu32" seconds, rebind in %"PRIu32
2316                     " seconds",
2317                     ifp->name, lease->renewaltime, lease->rebindtime);
2318         }
2319         state->state = DHS_BOUND;
2320         if (!state->lease.frominfo &&
2321             !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))) {
2322                 logdebugx("%s: writing lease `%s'",
2323                     ifp->name, state->leasefile);
2324                 if (dhcp_writefile(ifp->ctx, state->leasefile, 0640,
2325                     state->new, state->new_len) == -1)
2326                         logerr("dhcp_writefile: %s", state->leasefile);
2327         }
2328
2329         /* Close the BPF filter as we can now receive DHCP messages
2330          * on a UDP socket. */
2331         old_state = state->added;
2332         if (ctx->options & DHCPCD_MASTER ||
2333             state->old == NULL ||
2334             state->old->yiaddr != state->new->yiaddr || old_state & STATE_FAKE)
2335                 dhcp_close(ifp);
2336
2337         ipv4_applyaddr(ifp);
2338
2339         /* If not in master mode, open an address specific socket. */
2340         if (ctx->options & DHCPCD_MASTER ||
2341             (state->old != NULL &&
2342             state->old->yiaddr == state->new->yiaddr &&
2343             old_state & STATE_ADDED && !(old_state & STATE_FAKE)))
2344                 return;
2345
2346 #ifdef PRIVSEP
2347         if (IN_PRIVSEP_SE(ctx)) {
2348                 if (ps_inet_openbootp(state->addr) == -1)
2349                     logerr(__func__);
2350                 return;
2351         }
2352 #endif
2353
2354         state->udp_rfd = dhcp_openudp(&state->addr->addr);
2355         if (state->udp_rfd == -1) {
2356                 logerr(__func__);
2357                 /* Address sharing without master mode is not supported.
2358                  * It's also possible another DHCP client could be running,
2359                  * which is even worse.
2360                  * We still need to work, so re-open BPF. */
2361                 dhcp_openbpf(ifp);
2362                 return;
2363         }
2364         eloop_event_add(ctx->eloop, state->udp_rfd, dhcp_handleifudp, ifp);
2365 }
2366
2367 static void
2368 dhcp_lastlease(void *arg)
2369 {
2370         struct interface *ifp = arg;
2371         struct dhcp_state *state = D_STATE(ifp);
2372
2373         loginfox("%s: timed out contacting a DHCP server, using last lease",
2374             ifp->name);
2375         dhcp_bind(ifp);
2376         state->interval = 0;
2377         dhcp_discover(ifp);
2378 }
2379
2380 static size_t
2381 dhcp_message_new(struct bootp **bootp,
2382     const struct in_addr *addr, const struct in_addr *mask)
2383 {
2384         uint8_t *p;
2385         uint32_t cookie;
2386
2387         if ((*bootp = calloc(1, sizeof(**bootp))) == NULL)
2388                 return 0;
2389
2390         (*bootp)->yiaddr = addr->s_addr;
2391         p = (*bootp)->vend;
2392
2393         cookie = htonl(MAGIC_COOKIE);
2394         memcpy(p, &cookie, sizeof(cookie));
2395         p += sizeof(cookie);
2396
2397         if (mask->s_addr != INADDR_ANY) {
2398                 *p++ = DHO_SUBNETMASK;
2399                 *p++ = sizeof(mask->s_addr);
2400                 memcpy(p, &mask->s_addr, sizeof(mask->s_addr));
2401                 p+= sizeof(mask->s_addr);
2402         }
2403
2404         *p = DHO_END;
2405         return sizeof(**bootp);
2406 }
2407
2408 #if defined(ARP) || defined(KERNEL_RFC5227)
2409 static int
2410 dhcp_arp_address(struct interface *ifp)
2411 {
2412         struct dhcp_state *state;
2413         struct in_addr addr;
2414         struct ipv4_addr *ia;
2415
2416         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2417
2418         state = D_STATE(ifp);
2419         addr.s_addr = state->offer->yiaddr == INADDR_ANY ?
2420             state->offer->ciaddr : state->offer->yiaddr;
2421         /* If the interface already has the address configured
2422          * then we can't ARP for duplicate detection. */
2423         ia = ipv4_iffindaddr(ifp, &addr, NULL);
2424 #ifdef IN_IFF_NOTUSEABLE
2425         if (ia == NULL || ia->addr_flags & IN_IFF_NOTUSEABLE) {
2426                 state->state = DHS_PROBE;
2427                 if (ia == NULL) {
2428                         struct dhcp_lease l;
2429
2430                         get_lease(ifp, &l, state->offer, state->offer_len);
2431                         /* Add the address now, let the kernel handle DAD. */
2432                         ipv4_addaddr(ifp, &l.addr, &l.mask, &l.brd,
2433                             l.leasetime, l.rebindtime);
2434                 } else if (ia->addr_flags & IN_IFF_DUPLICATED)
2435                         dhcp_addr_duplicated(ifp, &ia->addr);
2436                 else
2437                         loginfox("%s: waiting for DAD on %s",
2438                             ifp->name, inet_ntoa(addr));
2439                 return 0;
2440         }
2441 #else
2442         if (!(ifp->flags & IFF_NOARP) &&
2443             ifp->options->options & DHCPCD_ARP)
2444         {
2445                 struct arp_state *astate;
2446                 struct dhcp_lease l;
2447
2448                 /* Even if the address exists, we need to defend it. */
2449                 astate = dhcp_arp_new(ifp, &addr);
2450                 if (astate == NULL)
2451                         return -1;
2452
2453                 if (ia == NULL) {
2454                         state->state = DHS_PROBE;
2455                         get_lease(ifp, &l, state->offer, state->offer_len);
2456                         loginfox("%s: probing address %s/%d",
2457                             ifp->name, inet_ntoa(l.addr), inet_ntocidr(l.mask));
2458                         /* We need to handle DAD. */
2459                         arp_probe(astate);
2460                         return 0;
2461                 }
2462         }
2463 #endif
2464
2465         return 1;
2466 }
2467
2468 static void
2469 dhcp_arp_bind(struct interface *ifp)
2470 {
2471
2472         if (ifp->ctx->options & DHCPCD_TEST ||
2473             dhcp_arp_address(ifp) == 1)
2474                 dhcp_bind(ifp);
2475 }
2476 #endif
2477
2478 static void
2479 dhcp_static(struct interface *ifp)
2480 {
2481         struct if_options *ifo;
2482         struct dhcp_state *state;
2483         struct ipv4_addr *ia;
2484
2485         state = D_STATE(ifp);
2486         ifo = ifp->options;
2487
2488         ia = NULL;
2489         if (ifo->req_addr.s_addr == INADDR_ANY &&
2490             (ia = ipv4_iffindaddr(ifp, NULL, NULL)) == NULL)
2491         {
2492                 loginfox("%s: waiting for 3rd party to "
2493                     "configure IP address", ifp->name);
2494                 state->reason = "3RDPARTY";
2495                 script_runreason(ifp, state->reason);
2496                 return;
2497         }
2498
2499         state->offer_len = dhcp_message_new(&state->offer,
2500             ia ? &ia->addr : &ifo->req_addr,
2501             ia ? &ia->mask : &ifo->req_mask);
2502         if (state->offer_len)
2503 #if defined(ARP) || defined(KERNEL_RFC5227)
2504                 dhcp_arp_bind(ifp);
2505 #else
2506                 dhcp_bind(ifp);
2507 #endif
2508 }
2509
2510 void
2511 dhcp_inform(struct interface *ifp)
2512 {
2513         struct dhcp_state *state;
2514         struct if_options *ifo;
2515         struct ipv4_addr *ia;
2516
2517         state = D_STATE(ifp);
2518         ifo = ifp->options;
2519
2520         state->state = DHS_INFORM;
2521         free(state->offer);
2522         state->offer = NULL;
2523         state->offer_len = 0;
2524
2525         if (ifo->req_addr.s_addr == INADDR_ANY) {
2526                 ia = ipv4_iffindaddr(ifp, NULL, NULL);
2527                 if (ia == NULL) {
2528                         loginfox("%s: waiting for 3rd party to "
2529                             "configure IP address",
2530                             ifp->name);
2531                         if (!(ifp->ctx->options & DHCPCD_TEST)) {
2532                                 state->reason = "3RDPARTY";
2533                                 script_runreason(ifp, state->reason);
2534                         }
2535                         return;
2536                 }
2537         } else {
2538                 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, &ifo->req_mask);
2539                 if (ia == NULL) {
2540                         if (ifp->ctx->options & DHCPCD_TEST) {
2541                                 logerrx("%s: cannot add IP address in test mode",
2542                                     ifp->name);
2543                                 return;
2544                         }
2545                         ia = ipv4_iffindaddr(ifp, &ifo->req_addr, NULL);
2546                         if (ia != NULL)
2547                                 /* Netmask must be different, delete it. */
2548                                 ipv4_deladdr(ia, 1);
2549                         state->offer_len = dhcp_message_new(&state->offer,
2550                             &ifo->req_addr, &ifo->req_mask);
2551 #ifdef ARP
2552                         if (dhcp_arp_address(ifp) != 1)
2553                                 return;
2554 #endif
2555                         ia = ipv4_iffindaddr(ifp,
2556                             &ifo->req_addr, &ifo->req_mask);
2557                         assert(ia != NULL);
2558                 }
2559         }
2560
2561         state->addr = ia;
2562         state->offer_len = dhcp_message_new(&state->offer,
2563             &ia->addr, &ia->mask);
2564         if (state->offer_len) {
2565                 dhcp_new_xid(ifp);
2566                 get_lease(ifp, &state->lease, state->offer, state->offer_len);
2567                 send_inform(ifp);
2568         }
2569 }
2570
2571 void
2572 dhcp_reboot_newopts(struct interface *ifp, unsigned long long oldopts)
2573 {
2574         struct if_options *ifo;
2575         struct dhcp_state *state = D_STATE(ifp);
2576
2577         if (state == NULL || state->state == DHS_NONE)
2578                 return;
2579         ifo = ifp->options;
2580         if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC) &&
2581                 (state->addr == NULL ||
2582                 state->addr->addr.s_addr != ifo->req_addr.s_addr)) ||
2583             (oldopts & (DHCPCD_INFORM | DHCPCD_STATIC) &&
2584                 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))))
2585         {
2586                 dhcp_drop(ifp, "EXPIRE");
2587         }
2588 }
2589
2590 #ifdef ARP
2591 static int
2592 dhcp_activeaddr(const struct interface *ifp, const struct in_addr *addr)
2593 {
2594         const struct interface *ifp1;
2595         const struct dhcp_state *state;
2596
2597         TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) {
2598                 if (ifp1 == ifp)
2599                         continue;
2600                 if ((state = D_CSTATE(ifp1)) == NULL)
2601                         continue;
2602                 switch(state->state) {
2603                 case DHS_REBOOT:
2604                 case DHS_RENEW:
2605                 case DHS_REBIND:
2606                 case DHS_BOUND:
2607                 case DHS_INFORM:
2608                         break;
2609                 default:
2610                         continue;
2611                 }
2612                 if (state->lease.addr.s_addr == addr->s_addr)
2613                         return 1;
2614         }
2615         return 0;
2616 }
2617 #endif
2618
2619 static void
2620 dhcp_reboot(struct interface *ifp)
2621 {
2622         struct if_options *ifo;
2623         struct dhcp_state *state = D_STATE(ifp);
2624 #ifdef ARP
2625         struct ipv4_addr *ia;
2626 #endif
2627
2628         if (state == NULL || state->state == DHS_NONE)
2629                 return;
2630         ifo = ifp->options;
2631         state->state = DHS_REBOOT;
2632         state->interval = 0;
2633
2634         if (ifo->options & DHCPCD_LINK && ifp->carrier <= LINK_DOWN) {
2635                 loginfox("%s: waiting for carrier", ifp->name);
2636                 return;
2637         }
2638         if (ifo->options & DHCPCD_STATIC) {
2639                 dhcp_static(ifp);
2640                 return;
2641         }
2642         if (ifo->options & DHCPCD_INFORM) {
2643                 loginfox("%s: informing address of %s",
2644                     ifp->name, inet_ntoa(state->lease.addr));
2645                 dhcp_inform(ifp);
2646                 return;
2647         }
2648         if (ifo->reboot == 0 || state->offer == NULL) {
2649                 dhcp_discover(ifp);
2650                 return;
2651         }
2652         if (!IS_DHCP(state->offer))
2653                 return;
2654
2655         loginfox("%s: rebinding lease of %s",
2656             ifp->name, inet_ntoa(state->lease.addr));
2657
2658 #ifdef ARP
2659 #ifndef KERNEL_RFC5227
2660         /* Create the DHCP ARP state so we can defend it. */
2661         (void)dhcp_arp_new(ifp, &state->lease.addr);
2662 #endif
2663
2664         /* If the address exists on the interface and no other interface
2665          * is currently using it then announce it to ensure this
2666          * interface gets the reply. */
2667         ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL);
2668         if (ia != NULL &&
2669             !(ifp->ctx->options & DHCPCD_TEST) &&
2670 #ifdef IN_IFF_NOTUSEABLE
2671             !(ia->addr_flags & IN_IFF_NOTUSEABLE) &&
2672 #endif
2673             dhcp_activeaddr(ifp, &state->lease.addr) == 0)
2674                 arp_ifannounceaddr(ifp, &state->lease.addr);
2675 #endif
2676
2677         dhcp_new_xid(ifp);
2678         state->lease.server.s_addr = INADDR_ANY;
2679         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2680
2681 #ifdef IPV4LL
2682         /* Need to add this before dhcp_expire and friends. */
2683         if (!ifo->fallback && ifo->options & DHCPCD_IPV4LL)
2684                 eloop_timeout_add_sec(ifp->ctx->eloop,
2685                     ifo->reboot, ipv4ll_start, ifp);
2686 #endif
2687
2688         if (ifo->options & DHCPCD_LASTLEASE && state->lease.frominfo)
2689                 eloop_timeout_add_sec(ifp->ctx->eloop,
2690                     ifo->reboot, dhcp_lastlease, ifp);
2691         else if (!(ifo->options & DHCPCD_INFORM))
2692                 eloop_timeout_add_sec(ifp->ctx->eloop,
2693                     ifo->reboot, dhcp_expire, ifp);
2694
2695         /* Don't bother ARP checking as the server could NAK us first.
2696          * Don't call dhcp_request as that would change the state */
2697         send_request(ifp);
2698 }
2699
2700 void
2701 dhcp_drop(struct interface *ifp, const char *reason)
2702 {
2703         struct dhcp_state *state;
2704 #ifdef RELEASE_SLOW
2705         struct timespec ts;
2706 #endif
2707
2708         state = D_STATE(ifp);
2709         /* dhcp_start may just have been called and we don't yet have a state
2710          * but we do have a timeout, so punt it. */
2711         if (state == NULL || state->state == DHS_NONE) {
2712                 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2713                 return;
2714         }
2715
2716 #ifdef ARP
2717         if (state->addr != NULL)
2718                 arp_freeaddr(ifp, &state->addr->addr);
2719 #endif
2720 #ifdef ARPING
2721         state->arping_index = -1;
2722 #endif
2723
2724         if (ifp->options->options & DHCPCD_RELEASE &&
2725             !(ifp->options->options & DHCPCD_INFORM))
2726         {
2727                 /* Failure to send the release may cause this function to
2728                  * re-enter so guard by setting the state. */
2729                 if (state->state == DHS_RELEASE)
2730                         return;
2731                 state->state = DHS_RELEASE;
2732
2733                 dhcp_unlink(ifp->ctx, state->leasefile);
2734                 if (ifp->carrier > LINK_DOWN &&
2735                     state->new != NULL &&
2736                     state->lease.server.s_addr != INADDR_ANY)
2737                 {
2738                         loginfox("%s: releasing lease of %s",
2739                             ifp->name, inet_ntoa(state->lease.addr));
2740                         dhcp_new_xid(ifp);
2741                         send_message(ifp, DHCP_RELEASE, NULL);
2742 #ifdef RELEASE_SLOW
2743                         /* Give the packet a chance to go */
2744                         ts.tv_sec = RELEASE_DELAY_S;
2745                         ts.tv_nsec = RELEASE_DELAY_NS;
2746                         nanosleep(&ts, NULL);
2747 #endif
2748                 }
2749         }
2750 #ifdef AUTH
2751         else if (state->auth.reconf != NULL) {
2752                 /*
2753                  * Drop the lease as the token may only be present
2754                  * in the initial reply message and not subsequent
2755                  * renewals.
2756                  * If dhcpcd is restarted, the token is lost.
2757                  * XXX persist this in another file?
2758                  */
2759                 dhcp_unlink(ifp->ctx, state->leasefile);
2760         }
2761 #endif
2762
2763         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2764 #ifdef AUTH
2765         dhcp_auth_reset(&state->auth);
2766 #endif
2767
2768         /* Close DHCP ports so a changed interface family is picked
2769          * up by a new BPF state. */
2770         dhcp_close(ifp);
2771
2772         state->state = DHS_NONE;
2773         free(state->offer);
2774         state->offer = NULL;
2775         state->offer_len = 0;
2776         free(state->old);
2777         state->old = state->new;
2778         state->old_len = state->new_len;
2779         state->new = NULL;
2780         state->new_len = 0;
2781         state->reason = reason;
2782         ipv4_applyaddr(ifp);
2783         free(state->old);
2784         state->old = NULL;
2785         state->old_len = 0;
2786         state->lease.addr.s_addr = 0;
2787         ifp->options->options &= ~(DHCPCD_CSR_WARNED |
2788             DHCPCD_ROUTER_HOST_ROUTE_WARNED);
2789 }
2790
2791 static int
2792 blacklisted_ip(const struct if_options *ifo, in_addr_t addr)
2793 {
2794         size_t i;
2795
2796         for (i = 0; i < ifo->blacklist_len; i += 2)
2797                 if (ifo->blacklist[i] == (addr & ifo->blacklist[i + 1]))
2798                         return 1;
2799         return 0;
2800 }
2801
2802 #define WHTLST_NONE     0
2803 #define WHTLST_MATCH    1
2804 #define WHTLST_NOMATCH  2
2805 static unsigned int
2806 whitelisted_ip(const struct if_options *ifo, in_addr_t addr)
2807 {
2808         size_t i;
2809
2810         if (ifo->whitelist_len == 0)
2811                 return WHTLST_NONE;
2812         for (i = 0; i < ifo->whitelist_len; i += 2)
2813                 if (ifo->whitelist[i] == (addr & ifo->whitelist[i + 1]))
2814                         return WHTLST_MATCH;
2815         return WHTLST_NOMATCH;
2816 }
2817
2818 static void
2819 log_dhcp(int loglevel, const char *msg,
2820     const struct interface *ifp, const struct bootp *bootp, size_t bootp_len,
2821     const struct in_addr *from, int ad)
2822 {
2823         const char *tfrom;
2824         char *a, sname[sizeof(bootp->sname) * 4];
2825         struct in_addr addr;
2826         int r;
2827         uint8_t overl;
2828
2829         if (strcmp(msg, "NAK:") == 0) {
2830                 a = get_option_string(ifp->ctx, bootp, bootp_len, DHO_MESSAGE);
2831                 if (a) {
2832                         char *tmp;
2833                         size_t al, tmpl;
2834
2835                         al = strlen(a);
2836                         tmpl = (al * 4) + 1;
2837                         tmp = malloc(tmpl);
2838                         if (tmp == NULL) {
2839                                 logerr(__func__);
2840                                 free(a);
2841                                 return;
2842                         }
2843                         print_string(tmp, tmpl, OT_STRING, (uint8_t *)a, al);
2844                         free(a);
2845                         a = tmp;
2846                 }
2847         } else if (ad && bootp->yiaddr != 0) {
2848                 addr.s_addr = bootp->yiaddr;
2849                 a = strdup(inet_ntoa(addr));
2850                 if (a == NULL) {
2851                         logerr(__func__);
2852                         return;
2853                 }
2854         } else
2855                 a = NULL;
2856
2857         tfrom = "from";
2858         r = get_option_addr(ifp->ctx, &addr, bootp, bootp_len, DHO_SERVERID);
2859         if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len,
2860             DHO_OPTSOVERLOADED) == -1)
2861                 overl = 0;
2862         if (bootp->sname[0] && r == 0 && !(overl & 2)) {
2863                 print_string(sname, sizeof(sname), OT_STRING | OT_DOMAIN,
2864                     bootp->sname, sizeof(bootp->sname));
2865                 if (a == NULL)
2866                         logmessage(loglevel, "%s: %s %s %s `%s'",
2867                             ifp->name, msg, tfrom, inet_ntoa(addr), sname);
2868                 else
2869                         logmessage(loglevel, "%s: %s %s %s %s `%s'",
2870                             ifp->name, msg, a, tfrom, inet_ntoa(addr), sname);
2871         } else {
2872                 if (r != 0) {
2873                         tfrom = "via";
2874                         addr = *from;
2875                 }
2876                 if (a == NULL)
2877                         logmessage(loglevel, "%s: %s %s %s",
2878                             ifp->name, msg, tfrom, inet_ntoa(addr));
2879                 else
2880                         logmessage(loglevel, "%s: %s %s %s %s",
2881                             ifp->name, msg, a, tfrom, inet_ntoa(addr));
2882         }
2883         free(a);
2884 }
2885
2886 /* If we're sharing the same IP address with another interface on the
2887  * same network, we may receive the DHCP reply on the wrong interface.
2888  * Try and re-direct it here. */
2889 static void
2890 dhcp_redirect_dhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
2891     const struct in_addr *from)
2892 {
2893         struct interface *ifn;
2894         const struct dhcp_state *state;
2895         uint32_t xid;
2896
2897         xid = ntohl(bootp->xid);
2898         TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
2899                 if (ifn == ifp)
2900                         continue;
2901                 state = D_CSTATE(ifn);
2902                 if (state == NULL || state->state == DHS_NONE)
2903                         continue;
2904                 if (state->xid != xid)
2905                         continue;
2906                 if (ifn->hwlen <= sizeof(bootp->chaddr) &&
2907                     memcmp(bootp->chaddr, ifn->hwaddr, ifn->hwlen))
2908                         continue;
2909                 logdebugx("%s: redirecting DHCP message to %s",
2910                     ifp->name, ifn->name);
2911                 dhcp_handledhcp(ifn, bootp, bootp_len, from);
2912         }
2913 }
2914
2915 static void
2916 dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
2917     const struct in_addr *from)
2918 {
2919         struct dhcp_state *state = D_STATE(ifp);
2920         struct if_options *ifo = ifp->options;
2921         struct dhcp_lease *lease = &state->lease;
2922         uint8_t type, tmp;
2923         struct in_addr addr;
2924         unsigned int i;
2925         char *msg;
2926         bool bootp_copied;
2927 #ifdef AUTH
2928         const uint8_t *auth;
2929         size_t auth_len;
2930 #endif
2931 #ifdef IN_IFF_DUPLICATED
2932         struct ipv4_addr *ia;
2933 #endif
2934
2935 #define LOGDHCP0(l, m) \
2936         log_dhcp((l), (m), ifp, bootp, bootp_len, from, 0)
2937 #define LOGDHCP(l, m) \
2938         log_dhcp((l), (m), ifp, bootp, bootp_len, from, 1)
2939
2940 #define IS_STATE_ACTIVE(s) ((s)-state != DHS_NONE && \
2941         (s)->state != DHS_INIT && (s)->state != DHS_BOUND)
2942
2943         if (bootp->op != BOOTREPLY) {
2944                 if (IS_STATE_ACTIVE(state))
2945                         logdebugx("%s: op (%d) is not BOOTREPLY",
2946                             ifp->name, bootp->op);
2947                 return;
2948         }
2949
2950         if (state->xid != ntohl(bootp->xid)) {
2951                 if (IS_STATE_ACTIVE(state))
2952                         logdebugx("%s: wrong xid 0x%x (expecting 0x%x) from %s",
2953                             ifp->name, ntohl(bootp->xid), state->xid,
2954                             inet_ntoa(*from));
2955                 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from);
2956                 return;
2957         }
2958
2959         if (ifp->hwlen <= sizeof(bootp->chaddr) &&
2960             memcmp(bootp->chaddr, ifp->hwaddr, ifp->hwlen))
2961         {
2962                 if (IS_STATE_ACTIVE(state)) {
2963                         char buf[sizeof(bootp->chaddr) * 3];
2964
2965                         logdebugx("%s: xid 0x%x is for hwaddr %s",
2966                             ifp->name, ntohl(bootp->xid),
2967                             hwaddr_ntoa(bootp->chaddr, sizeof(bootp->chaddr),
2968                                     buf, sizeof(buf)));
2969                 }
2970                 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from);
2971                 return;
2972         }
2973
2974         if (!ifp->active)
2975                 return;
2976
2977         i = whitelisted_ip(ifp->options, from->s_addr);
2978         switch (i) {
2979         case WHTLST_NOMATCH:
2980                 logwarnx("%s: non whitelisted DHCP packet from %s",
2981                     ifp->name, inet_ntoa(*from));
2982                 return;
2983         case WHTLST_MATCH:
2984                 break;
2985         case WHTLST_NONE:
2986                 if (blacklisted_ip(ifp->options, from->s_addr) == 1) {
2987                         logwarnx("%s: blacklisted DHCP packet from %s",
2988                             ifp->name, inet_ntoa(*from));
2989                         return;
2990                 }
2991         }
2992
2993         /* We may have found a BOOTP server */
2994         if (get_option_uint8(ifp->ctx, &type,
2995             bootp, bootp_len, DHO_MESSAGETYPE) == -1)
2996                 type = 0;
2997         else if (ifo->options & DHCPCD_BOOTP) {
2998                 logdebugx("%s: ignoring DHCP reply (expecting BOOTP)",
2999                     ifp->name);
3000                 return;
3001         }
3002
3003 #ifdef AUTH
3004         /* Authenticate the message */
3005         auth = get_option(ifp->ctx, bootp, bootp_len,
3006             DHO_AUTHENTICATION, &auth_len);
3007         if (auth) {
3008                 if (dhcp_auth_validate(&state->auth, &ifo->auth,
3009                     (uint8_t *)bootp, bootp_len, 4, type,
3010                     auth, auth_len) == NULL)
3011                 {
3012                         LOGDHCP0(LOG_ERR, "authentication failed");
3013                         return;
3014                 }
3015                 if (state->auth.token)
3016                         logdebugx("%s: validated using 0x%08" PRIu32,
3017                             ifp->name, state->auth.token->secretid);
3018                 else
3019                         loginfox("%s: accepted reconfigure key", ifp->name);
3020         } else if (ifo->auth.options & DHCPCD_AUTH_SEND) {
3021                 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) {
3022                         LOGDHCP0(LOG_ERR, "no authentication");
3023                         return;
3024                 }
3025                 LOGDHCP0(LOG_WARNING, "no authentication");
3026         }
3027 #endif
3028
3029         /* RFC 3203 */
3030         if (type == DHCP_FORCERENEW) {
3031                 if (from->s_addr == INADDR_ANY ||
3032                     from->s_addr == INADDR_BROADCAST)
3033                 {
3034                         LOGDHCP(LOG_ERR, "discarding Force Renew");
3035                         return;
3036                 }
3037 #ifdef AUTH
3038                 if (auth == NULL) {
3039                         LOGDHCP(LOG_ERR, "unauthenticated Force Renew");
3040                         if (ifo->auth.options & DHCPCD_AUTH_REQUIRE)
3041                                 return;
3042                 }
3043                 if (state->state != DHS_BOUND && state->state != DHS_INFORM) {
3044                         LOGDHCP(LOG_DEBUG, "not bound, ignoring Force Renew");
3045                         return;
3046                 }
3047                 LOGDHCP(LOG_INFO, "Force Renew from");
3048                 /* The rebind and expire timings are still the same, we just
3049                  * enter the renew state early */
3050                 if (state->state == DHS_BOUND)
3051                         dhcp_renew(ifp);
3052                 else {
3053                         eloop_timeout_delete(ifp->ctx->eloop,
3054                             send_inform, ifp);
3055                         dhcp_inform(ifp);
3056                 }
3057 #else
3058                 LOGDHCP(LOG_ERR, "unauthenticated Force Renew");
3059 #endif
3060                 return;
3061         }
3062
3063         if (state->state == DHS_BOUND) {
3064                 LOGDHCP(LOG_DEBUG, "bound, ignoring");
3065                 return;
3066         }
3067
3068         if (state->state == DHS_PROBE) {
3069                 /* Ignore any DHCP messages whilst probing a lease to bind. */
3070                 LOGDHCP(LOG_DEBUG, "probing, ignoring");
3071                 return;
3072         }
3073
3074         /* reset the message counter */
3075         state->interval = 0;
3076
3077         /* Ensure that no reject options are present */
3078         for (i = 1; i < 255; i++) {
3079                 if (has_option_mask(ifo->rejectmask, i) &&
3080                     get_option_uint8(ifp->ctx, &tmp,
3081                     bootp, bootp_len, (uint8_t)i) == 0)
3082                 {
3083                         LOGDHCP(LOG_WARNING, "reject DHCP");
3084                         return;
3085                 }
3086         }
3087
3088         if (type == DHCP_NAK) {
3089                 /* For NAK, only check if we require the ServerID */
3090                 if (has_option_mask(ifo->requiremask, DHO_SERVERID) &&
3091                     get_option_addr(ifp->ctx, &addr,
3092                     bootp, bootp_len, DHO_SERVERID) == -1)
3093                 {
3094                         LOGDHCP(LOG_WARNING, "reject NAK");
3095                         return;
3096                 }
3097
3098                 /* We should restart on a NAK */
3099                 LOGDHCP(LOG_WARNING, "NAK:");
3100                 if ((msg = get_option_string(ifp->ctx,
3101                     bootp, bootp_len, DHO_MESSAGE)))
3102                 {
3103                         logwarnx("%s: message: %s", ifp->name, msg);
3104                         free(msg);
3105                 }
3106                 if (state->state == DHS_INFORM) /* INFORM should not be NAKed */
3107                         return;
3108                 if (!(ifp->ctx->options & DHCPCD_TEST)) {
3109                         dhcp_drop(ifp, "NAK");
3110                         dhcp_unlink(ifp->ctx, state->leasefile);
3111                 }
3112
3113                 /* If we constantly get NAKS then we should slowly back off */
3114                 eloop_timeout_add_sec(ifp->ctx->eloop,
3115                     state->nakoff, dhcp_discover, ifp);
3116                 if (state->nakoff == 0)
3117                         state->nakoff = 1;
3118                 else {
3119                         state->nakoff *= 2;
3120                         if (state->nakoff > NAKOFF_MAX)
3121                                 state->nakoff = NAKOFF_MAX;
3122                 }
3123                 return;
3124         }
3125
3126         /* Ensure that all required options are present */
3127         for (i = 1; i < 255; i++) {
3128                 if (has_option_mask(ifo->requiremask, i) &&
3129                     get_option_uint8(ifp->ctx, &tmp,
3130                     bootp, bootp_len, (uint8_t)i) != 0)
3131                 {
3132                         /* If we are BOOTP, then ignore the need for serverid.
3133                          * To ignore BOOTP, require dhcp_message_type.
3134                          * However, nothing really stops BOOTP from providing
3135                          * DHCP style options as well so the above isn't
3136                          * always true. */
3137                         if (type == 0 && i == DHO_SERVERID)
3138                                 continue;
3139                         LOGDHCP(LOG_WARNING, "reject DHCP");
3140                         return;
3141                 }
3142         }
3143
3144         /* DHCP Auto-Configure, RFC 2563 */
3145         if (type == DHCP_OFFER && bootp->yiaddr == 0) {
3146                 LOGDHCP(LOG_WARNING, "no address given");
3147                 if ((msg = get_option_string(ifp->ctx,
3148                     bootp, bootp_len, DHO_MESSAGE)))
3149                 {
3150                         logwarnx("%s: message: %s", ifp->name, msg);
3151                         free(msg);
3152                 }
3153 #ifdef IPV4LL
3154                 if (state->state == DHS_DISCOVER &&
3155                     get_option_uint8(ifp->ctx, &tmp, bootp, bootp_len,
3156                     DHO_AUTOCONFIGURE) == 0)
3157                 {
3158                         switch (tmp) {
3159                         case 0:
3160                                 LOGDHCP(LOG_WARNING, "IPv4LL disabled from");
3161                                 ipv4ll_drop(ifp);
3162 #ifdef ARP
3163                                 arp_drop(ifp);
3164 #endif
3165                                 break;
3166                         case 1:
3167                                 LOGDHCP(LOG_WARNING, "IPv4LL enabled from");
3168                                 ipv4ll_start(ifp);
3169                                 break;
3170                         default:
3171                                 logerrx("%s: unknown auto configuration "
3172                                     "option %d",
3173                                     ifp->name, tmp);
3174                                 break;
3175                         }
3176                         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3177                         eloop_timeout_add_sec(ifp->ctx->eloop,
3178                             DHCP_MAX, dhcp_discover, ifp);
3179                 }
3180 #endif
3181                 return;
3182         }
3183
3184         /* Ensure that the address offered is valid */
3185         if ((type == 0 || type == DHCP_OFFER || type == DHCP_ACK) &&
3186             (bootp->ciaddr == INADDR_ANY || bootp->ciaddr == INADDR_BROADCAST)
3187             &&
3188             (bootp->yiaddr == INADDR_ANY || bootp->yiaddr == INADDR_BROADCAST))
3189         {
3190                 LOGDHCP(LOG_WARNING, "reject invalid address");
3191                 return;
3192         }
3193
3194 #ifdef IN_IFF_DUPLICATED
3195         ia = ipv4_iffindaddr(ifp, &lease->addr, NULL);
3196         if (ia && ia->addr_flags & IN_IFF_DUPLICATED) {
3197                 LOGDHCP(LOG_WARNING, "declined duplicate address");
3198                 if (type)
3199                         dhcp_decline(ifp);
3200                 ipv4_deladdr(ia, 0);
3201                 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3202                 eloop_timeout_add_sec(ifp->ctx->eloop,
3203                     DHCP_RAND_MAX, dhcp_discover, ifp);
3204                 return;
3205         }
3206 #endif
3207
3208         bootp_copied = false;
3209         if ((type == 0 || type == DHCP_OFFER) && state->state == DHS_DISCOVER) {
3210                 lease->frominfo = 0;
3211                 lease->addr.s_addr = bootp->yiaddr;
3212                 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie));
3213                 if (type == 0 ||
3214                     get_option_addr(ifp->ctx,
3215                     &lease->server, bootp, bootp_len, DHO_SERVERID) != 0)
3216                         lease->server.s_addr = INADDR_ANY;
3217
3218                 /* Test for rapid commit in the OFFER */
3219                 if (!(ifp->ctx->options & DHCPCD_TEST) &&
3220                     has_option_mask(ifo->requestmask, DHO_RAPIDCOMMIT) &&
3221                     get_option(ifp->ctx, bootp, bootp_len,
3222                     DHO_RAPIDCOMMIT, NULL))
3223                 {
3224                         state->state = DHS_REQUEST;
3225                         goto rapidcommit;
3226                 }
3227
3228                 LOGDHCP(LOG_INFO, "offered");
3229                 if (state->offer_len < bootp_len) {
3230                         free(state->offer);
3231                         if ((state->offer = malloc(bootp_len)) == NULL) {
3232                                 logerr(__func__);
3233                                 state->offer_len = 0;
3234                                 return;
3235                         }
3236                 }
3237                 state->offer_len = bootp_len;
3238                 memcpy(state->offer, bootp, bootp_len);
3239                 bootp_copied = true;
3240                 if (ifp->ctx->options & DHCPCD_TEST) {
3241                         free(state->old);
3242                         state->old = state->new;
3243                         state->old_len = state->new_len;
3244                         state->new = state->offer;
3245                         state->new_len = state->offer_len;
3246                         state->offer = NULL;
3247                         state->offer_len = 0;
3248                         state->reason = "TEST";
3249                         script_runreason(ifp, state->reason);
3250                         eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS);
3251                         state->bpf->bpf_flags |= BPF_EOF;
3252                         return;
3253                 }
3254                 eloop_timeout_delete(ifp->ctx->eloop, send_discover, ifp);
3255                 /* We don't request BOOTP addresses */
3256                 if (type) {
3257                         /* We used to ARP check here, but that seems to be in
3258                          * violation of RFC2131 where it only describes
3259                          * DECLINE after REQUEST.
3260                          * It also seems that some MS DHCP servers actually
3261                          * ignore DECLINE if no REQUEST, ie we decline a
3262                          * DISCOVER. */
3263                         dhcp_request(ifp);
3264                         return;
3265                 }
3266         }
3267
3268         if (type) {
3269                 if (type == DHCP_OFFER) {
3270                         LOGDHCP(LOG_WARNING, "ignoring offer of");
3271                         return;
3272                 }
3273
3274                 /* We should only be dealing with acks */
3275                 if (type != DHCP_ACK) {
3276                         LOGDHCP(LOG_ERR, "not ACK or OFFER");
3277                         return;
3278                 }
3279
3280                 if (state->state == DHS_DISCOVER) {
3281                         /* We only allow ACK of rapid commit DISCOVER. */
3282                         if (has_option_mask(ifo->requestmask,
3283                             DHO_RAPIDCOMMIT) &&
3284                             get_option(ifp->ctx, bootp, bootp_len,
3285                             DHO_RAPIDCOMMIT, NULL))
3286                                 state->state = DHS_REQUEST;
3287                         else {
3288                                 LOGDHCP(LOG_DEBUG, "ignoring ack of");
3289                                 return;
3290                         }
3291                 }
3292
3293 rapidcommit:
3294                 if (!(ifo->options & DHCPCD_INFORM))
3295                         LOGDHCP(LOG_DEBUG, "acknowledged");
3296                 else
3297                     ifo->options &= ~DHCPCD_STATIC;
3298         }
3299
3300         /* No NAK, so reset the backoff
3301          * We don't reset on an OFFER message because the server could
3302          * potentially NAK the REQUEST. */
3303         state->nakoff = 0;
3304
3305         /* BOOTP could have already assigned this above. */
3306         if (!bootp_copied) {
3307                 if (state->offer_len < bootp_len) {
3308                         free(state->offer);
3309                         if ((state->offer = malloc(bootp_len)) == NULL) {
3310                                 logerr(__func__);
3311                                 state->offer_len = 0;
3312                                 return;
3313                         }
3314                 }
3315                 state->offer_len = bootp_len;
3316                 memcpy(state->offer, bootp, bootp_len);
3317         }
3318
3319         lease->frominfo = 0;
3320         eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3321
3322 #if defined(ARP) || defined(KERNEL_RFC5227)
3323         dhcp_arp_bind(ifp);
3324 #else
3325         dhcp_bind(ifp);
3326 #endif
3327 }
3328
3329 static void *
3330 get_udp_data(void *packet, size_t *len)
3331 {
3332         const struct ip *ip = packet;
3333         size_t ip_hl = (size_t)ip->ip_hl * 4;
3334         char *p = packet;
3335
3336         p += ip_hl + sizeof(struct udphdr);
3337         *len = (size_t)ntohs(ip->ip_len) - sizeof(struct udphdr) - ip_hl;
3338         return p;
3339 }
3340
3341 static bool
3342 is_packet_udp_bootp(void *packet, size_t plen)
3343 {
3344         struct ip *ip = packet;
3345         size_t ip_hlen;
3346         struct udphdr udp;
3347
3348         if (plen < sizeof(*ip))
3349                 return false;
3350
3351         if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP)
3352                 return false;
3353
3354         /* Sanity. */
3355         if (ntohs(ip->ip_len) > plen)
3356                 return false;
3357
3358         ip_hlen = (size_t)ip->ip_hl * 4;
3359         if (ip_hlen < sizeof(*ip))
3360                 return false;
3361
3362         /* Check we have a UDP header and BOOTP. */
3363         if (ip_hlen + sizeof(udp) + offsetof(struct bootp, vend) > plen)
3364                 return false;
3365
3366         /* Sanity. */
3367         memcpy(&udp, (char *)ip + ip_hlen, sizeof(udp));
3368         if (ntohs(udp.uh_ulen) < sizeof(udp))
3369                 return false;
3370         if (ip_hlen + ntohs(udp.uh_ulen) > plen)
3371                 return false;
3372
3373         /* Check it's to and from the right ports. */
3374         if (udp.uh_dport != htons(BOOTPC) || udp.uh_sport != htons(BOOTPS))
3375                 return false;
3376
3377         return true;
3378 }
3379
3380 /* Lengths have already been checked. */
3381 static bool
3382 checksums_valid(void *packet,
3383     struct in_addr *from, unsigned int flags)
3384 {
3385         struct ip *ip = packet;
3386         union pip {
3387                 struct ip ip;
3388                 uint16_t w[sizeof(struct ip) / 2];
3389         } pip = {
3390                 .ip = {
3391                         .ip_p = IPPROTO_UDP,
3392                         .ip_src = ip->ip_src,
3393                         .ip_dst = ip->ip_dst,
3394                 }
3395         };
3396         size_t ip_hlen;
3397         struct udphdr udp;
3398         char *udpp, *uh_sump;
3399         uint32_t csum;
3400
3401         if (from != NULL)
3402                 from->s_addr = ip->ip_src.s_addr;
3403
3404         ip_hlen = (size_t)ip->ip_hl * 4;
3405         if (in_cksum(ip, ip_hlen, NULL) != 0)
3406                 return false;
3407
3408         if (flags & BPF_PARTIALCSUM)
3409                 return true;
3410
3411         udpp = (char *)ip + ip_hlen;
3412         memcpy(&udp, udpp, sizeof(udp));
3413         if (udp.uh_sum == 0)
3414                 return true;
3415
3416         /* UDP checksum is based on a pseudo IP header alongside
3417          * the UDP header and payload. */
3418         pip.ip.ip_len = udp.uh_ulen;
3419         csum = 0;
3420
3421         /* Need to zero the UDP sum in the packet for the checksum to work. */
3422         uh_sump = udpp + offsetof(struct udphdr, uh_sum);
3423         memset(uh_sump, 0, sizeof(udp.uh_sum));
3424
3425         /* Checksum pseudo header and then UDP + payload. */
3426         in_cksum(pip.w, sizeof(pip.w), &csum);
3427         csum = in_cksum(udpp, ntohs(udp.uh_ulen), &csum);
3428
3429 #if 0   /* Not needed, just here for completeness. */
3430         /* Put the checksum back. */
3431         memcpy(uh_sump, &udp.uh_sum, sizeof(udp.uh_sum));
3432 #endif
3433
3434         return csum == udp.uh_sum;
3435 }
3436
3437 static void
3438 dhcp_handlebootp(struct interface *ifp, struct bootp *bootp, size_t len,
3439     struct in_addr *from)
3440 {
3441         size_t v;
3442
3443         if (len < offsetof(struct bootp, vend)) {
3444                 logerrx("%s: truncated packet (%zu) from %s",
3445                     ifp->name, len, inet_ntoa(*from));
3446                 return;
3447         }
3448
3449         /* Unlikely, but appeases sanitizers. */
3450         if (len > FRAMELEN_MAX) {
3451                 logerrx("%s: packet exceeded frame length (%zu) from %s",
3452                     ifp->name, len, inet_ntoa(*from));
3453                 return;
3454         }
3455
3456         /* To make our IS_DHCP macro easy, ensure the vendor
3457          * area has at least 4 octets. */
3458         v = len - offsetof(struct bootp, vend);
3459         while (v < 4) {
3460                 bootp->vend[v++] = '\0';
3461                 len++;
3462         }
3463
3464         dhcp_handledhcp(ifp, bootp, len, from);
3465 }
3466
3467 void
3468 dhcp_packet(struct interface *ifp, uint8_t *data, size_t len,
3469     unsigned int bpf_flags)
3470 {
3471         struct bootp *bootp;
3472         struct in_addr from;
3473         size_t udp_len;
3474         size_t fl = bpf_frame_header_len(ifp);
3475 #ifdef PRIVSEP
3476         const struct dhcp_state *state = D_CSTATE(ifp);
3477
3478         /* Ignore double reads */
3479         if (IN_PRIVSEP(ifp->ctx)) {
3480                 switch (state->state) {
3481                 case DHS_BOUND: /* FALLTHROUGH */
3482                 case DHS_RENEW:
3483                         return;
3484                 default:
3485                         break;
3486                 }
3487         }
3488 #endif
3489
3490         /* Trim frame header */
3491         if (fl != 0) {
3492                 if (len < fl) {
3493                         logerrx("%s: %s: short frame header %zu",
3494                             __func__, ifp->name, len);
3495                         return;
3496                 }
3497                 len -= fl;
3498                 /* Move the data to avoid alignment errors. */
3499                 memmove(data, data + fl, len);
3500         }
3501
3502         /* Validate filter. */
3503         if (!is_packet_udp_bootp(data, len)) {
3504 #ifdef BPF_DEBUG
3505                 logerrx("%s: DHCP BPF validation failure", ifp->name);
3506 #endif
3507                 return;
3508         }
3509
3510         if (!checksums_valid(data, &from, bpf_flags)) {
3511                 logerrx("%s: checksum failure from %s",
3512                     ifp->name, inet_ntoa(from));
3513                 return;
3514         }
3515
3516         /*
3517          * DHCP has a variable option area rather than a fixed vendor area.
3518          * Because DHCP uses the BOOTP protocol it should still send BOOTP
3519          * sized packets to be RFC compliant.
3520          * However some servers send a truncated vendor area.
3521          * dhcpcd can work fine without the vendor area being sent.
3522          */
3523         bootp = get_udp_data(data, &udp_len);
3524         dhcp_handlebootp(ifp, bootp, udp_len, &from);
3525 }
3526
3527 static void
3528 dhcp_readbpf(void *arg)
3529 {
3530         struct interface *ifp = arg;
3531         uint8_t buf[FRAMELEN_MAX];
3532         ssize_t bytes;
3533         struct dhcp_state *state = D_STATE(ifp);
3534         struct bpf *bpf = state->bpf;
3535
3536         bpf->bpf_flags &= ~BPF_EOF;
3537         while (!(bpf->bpf_flags & BPF_EOF)) {
3538                 bytes = bpf_read(bpf, buf, sizeof(buf));
3539                 if (bytes == -1) {
3540                         if (state->state != DHS_NONE) {
3541                                 logerr("%s: %s", __func__, ifp->name);
3542                                 dhcp_close(ifp);
3543                         }
3544                         break;
3545                 }
3546                 dhcp_packet(ifp, buf, (size_t)bytes, bpf->bpf_flags);
3547                 /* Check we still have a state after processing. */
3548                 if ((state = D_STATE(ifp)) == NULL)
3549                         break;
3550                 if ((bpf = state->bpf) == NULL)
3551                         break;
3552         }
3553 }
3554
3555 void
3556 dhcp_recvmsg(struct dhcpcd_ctx *ctx, struct msghdr *msg)
3557 {
3558         struct sockaddr_in *from = (struct sockaddr_in *)msg->msg_name;
3559         struct iovec *iov = &msg->msg_iov[0];
3560         struct interface *ifp;
3561         const struct dhcp_state *state;
3562
3563         ifp = if_findifpfromcmsg(ctx, msg, NULL);
3564         if (ifp == NULL) {
3565                 logerr(__func__);
3566                 return;
3567         }
3568         state = D_CSTATE(ifp);
3569         if (state == NULL) {
3570                 /* Try re-directing it to another interface. */
3571                 dhcp_redirect_dhcp(ifp, (struct bootp *)iov->iov_base,
3572                     iov->iov_len, &from->sin_addr);
3573                 return;
3574         }
3575
3576         if (state->bpf != NULL) {
3577                 /* Avoid a duplicate read if BPF is open for the interface. */
3578                 return;
3579         }
3580 #ifdef PRIVSEP
3581         if (IN_PRIVSEP(ctx)) {
3582                 switch (state->state) {
3583                 case DHS_BOUND: /* FALLTHROUGH */
3584                 case DHS_RENEW:
3585                         break;
3586                 default:
3587                         /* Any other state we ignore it or will receive
3588                          * via BPF. */
3589                         return;
3590                 }
3591         }
3592 #endif
3593
3594         dhcp_handlebootp(ifp, iov->iov_base, iov->iov_len,
3595             &from->sin_addr);
3596 }
3597
3598 static void
3599 dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp)
3600 {
3601         const struct dhcp_state *state;
3602         struct sockaddr_in from;
3603         union {
3604                 struct bootp bootp;
3605                 uint8_t buf[10 * 1024]; /* Maximum MTU */
3606         } iovbuf;
3607         struct iovec iov = {
3608                 .iov_base = iovbuf.buf,
3609                 .iov_len = sizeof(iovbuf.buf),
3610         };
3611         union {
3612                 struct cmsghdr hdr;
3613 #ifdef IP_RECVIF
3614                 uint8_t buf[CMSG_SPACE(sizeof(struct sockaddr_dl))];
3615 #else
3616                 uint8_t buf[CMSG_SPACE(sizeof(struct in_pktinfo))];
3617 #endif
3618         } cmsgbuf = { .buf = { 0 } };
3619         struct msghdr msg = {
3620             .msg_name = &from, .msg_namelen = sizeof(from),
3621             .msg_iov = &iov, .msg_iovlen = 1,
3622             .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf),
3623         };
3624         int s;
3625         ssize_t bytes;
3626
3627         if (ifp != NULL) {
3628                 state = D_CSTATE(ifp);
3629                 s = state->udp_rfd;
3630         } else
3631                 s = ctx->udp_rfd;
3632
3633         bytes = recvmsg(s, &msg, 0);
3634         if (bytes == -1) {
3635                 logerr(__func__);
3636                 return;
3637         }
3638
3639         iov.iov_len = (size_t)bytes;
3640         dhcp_recvmsg(ctx, &msg);
3641 }
3642
3643 static void
3644 dhcp_handleudp(void *arg)
3645 {
3646         struct dhcpcd_ctx *ctx = arg;
3647
3648         dhcp_readudp(ctx, NULL);
3649 }
3650
3651 static void
3652 dhcp_handleifudp(void *arg)
3653 {
3654         struct interface *ifp = arg;
3655
3656         dhcp_readudp(ifp->ctx, ifp);
3657 }
3658
3659 static int
3660 dhcp_openbpf(struct interface *ifp)
3661 {
3662         struct dhcp_state *state;
3663
3664         state = D_STATE(ifp);
3665
3666 #ifdef PRIVSEP
3667         if (IN_PRIVSEP_SE(ifp->ctx)) {
3668                 if (ps_bpf_openbootp(ifp) == -1) {
3669                         logerr(__func__);
3670                         return -1;
3671                 }
3672                 return 0;
3673         }
3674 #endif
3675
3676         if (state->bpf != NULL)
3677                 return 0;
3678
3679         state->bpf = bpf_open(ifp, bpf_bootp, NULL);
3680         if (state->bpf == NULL) {
3681                 if (errno == ENOENT) {
3682                         logerrx("%s not found", bpf_name);
3683                         /* May as well disable IPv4 entirely at
3684                          * this point as we really need it. */
3685                         ifp->options->options &= ~DHCPCD_IPV4;
3686                 } else
3687                         logerr("%s: %s", __func__, ifp->name);
3688                 return -1;
3689         }
3690
3691         eloop_event_add(ifp->ctx->eloop,
3692             state->bpf->bpf_fd, dhcp_readbpf, ifp);
3693         return 0;
3694 }
3695
3696 void
3697 dhcp_free(struct interface *ifp)
3698 {
3699         struct dhcp_state *state = D_STATE(ifp);
3700         struct dhcpcd_ctx *ctx;
3701
3702         dhcp_close(ifp);
3703 #ifdef ARP
3704         arp_drop(ifp);
3705 #endif
3706         if (state) {
3707                 state->state = DHS_NONE;
3708                 free(state->old);
3709                 free(state->new);
3710                 free(state->offer);
3711                 free(state->clientid);
3712                 free(state);
3713         }
3714
3715         ctx = ifp->ctx;
3716         /* If we don't have any more DHCP enabled interfaces,
3717          * close the global socket and release resources */
3718         if (ctx->ifaces) {
3719                 TAILQ_FOREACH(ifp, ctx->ifaces, next) {
3720                         state = D_STATE(ifp);
3721                         if (state != NULL && state->state != DHS_NONE)
3722                                 break;
3723                 }
3724         }
3725         if (ifp == NULL) {
3726                 if (ctx->udp_rfd != -1) {
3727                         eloop_event_delete(ctx->eloop, ctx->udp_rfd);
3728                         close(ctx->udp_rfd);
3729                         ctx->udp_rfd = -1;
3730                 }
3731                 if (ctx->udp_wfd != -1) {
3732                         close(ctx->udp_wfd);
3733                         ctx->udp_wfd = -1;
3734                 }
3735
3736                 free(ctx->opt_buffer);
3737                 ctx->opt_buffer = NULL;
3738         }
3739 }
3740
3741 static int
3742 dhcp_initstate(struct interface *ifp)
3743 {
3744         struct dhcp_state *state;
3745
3746         state = D_STATE(ifp);
3747         if (state != NULL)
3748                 return 0;
3749
3750         ifp->if_data[IF_DATA_DHCP] = calloc(1, sizeof(*state));
3751         state = D_STATE(ifp);
3752         if (state == NULL)
3753                 return -1;
3754
3755         state->state = DHS_NONE;
3756         /* 0 is a valid fd, so init to -1 */
3757         state->udp_rfd = -1;
3758 #ifdef ARPING
3759         state->arping_index = -1;
3760 #endif
3761         return 1;
3762 }
3763
3764 static int
3765 dhcp_init(struct interface *ifp)
3766 {
3767         struct dhcp_state *state;
3768         struct if_options *ifo;
3769         uint8_t len;
3770         char buf[(sizeof(ifo->clientid) - 1) * 3];
3771
3772         if (dhcp_initstate(ifp) == -1)
3773                 return -1;
3774
3775         state = D_STATE(ifp);
3776         state->state = DHS_INIT;
3777         state->reason = "PREINIT";
3778         state->nakoff = 0;
3779         dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile),
3780             AF_INET, ifp);
3781
3782         ifo = ifp->options;
3783         /* We need to drop the leasefile so that dhcp_start
3784          * doesn't load it. */
3785         if (ifo->options & DHCPCD_REQUEST)
3786                 dhcp_unlink(ifp->ctx, state->leasefile);
3787
3788         free(state->clientid);
3789         state->clientid = NULL;
3790
3791         if (ifo->options & DHCPCD_ANONYMOUS) {
3792                 uint8_t duid[DUID_LEN];
3793                 uint8_t duid_len;
3794
3795                 duid_len = (uint8_t)duid_make(duid, ifp, DUID_LL);
3796                 if (duid_len != 0) {
3797                         state->clientid = malloc((size_t)duid_len + 6);
3798                         if (state->clientid == NULL)
3799                                 goto eexit;
3800                         state->clientid[0] =(uint8_t)(duid_len + 5);
3801                         state->clientid[1] = 255; /* RFC 4361 */
3802                         memcpy(state->clientid + 2, ifo->iaid, 4);
3803                         memset(state->clientid + 2, 0, 4); /* IAID */
3804                         memcpy(state->clientid + 6, duid, duid_len);
3805                 }
3806         } else if (*ifo->clientid) {
3807                 state->clientid = malloc((size_t)(ifo->clientid[0] + 1));
3808                 if (state->clientid == NULL)
3809                         goto eexit;
3810                 memcpy(state->clientid, ifo->clientid,
3811                     (size_t)(ifo->clientid[0]) + 1);
3812         } else if (ifo->options & DHCPCD_CLIENTID) {
3813                 if (ifo->options & DHCPCD_DUID) {
3814                         state->clientid = malloc(ifp->ctx->duid_len + 6);
3815                         if (state->clientid == NULL)
3816                                 goto eexit;
3817                         state->clientid[0] =(uint8_t)(ifp->ctx->duid_len + 5);
3818                         state->clientid[1] = 255; /* RFC 4361 */
3819                         memcpy(state->clientid + 2, ifo->iaid, 4);
3820                         memcpy(state->clientid + 6, ifp->ctx->duid,
3821                             ifp->ctx->duid_len);
3822                 } else {
3823                         len = (uint8_t)(ifp->hwlen + 1);
3824                         state->clientid = malloc((size_t)len + 1);
3825                         if (state->clientid == NULL)
3826                                 goto eexit;
3827                         state->clientid[0] = len;
3828                         state->clientid[1] = (uint8_t)ifp->hwtype;
3829                         memcpy(state->clientid + 2, ifp->hwaddr,
3830                             ifp->hwlen);
3831                 }
3832         }
3833
3834         if (ifo->options & DHCPCD_DUID)
3835                 /* Don't bother logging as DUID and IAID are reported
3836                  * at device start. */
3837                 return 0;
3838
3839         if (ifo->options & DHCPCD_CLIENTID && state->clientid != NULL)
3840                 logdebugx("%s: using ClientID %s", ifp->name,
3841                     hwaddr_ntoa(state->clientid + 1, state->clientid[0],
3842                         buf, sizeof(buf)));
3843         else if (ifp->hwlen)
3844                 logdebugx("%s: using hwaddr %s", ifp->name,
3845                     hwaddr_ntoa(ifp->hwaddr, ifp->hwlen, buf, sizeof(buf)));
3846         return 0;
3847
3848 eexit:
3849         logerr(__func__);
3850         return -1;
3851 }
3852
3853 static void
3854 dhcp_start1(void *arg)
3855 {
3856         struct interface *ifp = arg;
3857         struct dhcpcd_ctx *ctx = ifp->ctx;
3858         struct if_options *ifo = ifp->options;
3859         struct dhcp_state *state;
3860         uint32_t l;
3861         int nolease;
3862
3863         if (!(ifo->options & DHCPCD_IPV4))
3864                 return;
3865
3866         /* Listen on *.*.*.*:bootpc so that the kernel never sends an
3867          * ICMP port unreachable message back to the DHCP server.
3868          * Only do this in master mode so we don't swallow messages
3869          * for dhcpcd running on another interface. */
3870         if ((ctx->options & (DHCPCD_MASTER|DHCPCD_PRIVSEP)) == DHCPCD_MASTER
3871             && ctx->udp_rfd == -1)
3872         {
3873                 ctx->udp_rfd = dhcp_openudp(NULL);
3874                 if (ctx->udp_rfd == -1) {
3875                         logerr(__func__);
3876                         return;
3877                 }
3878                 eloop_event_add(ctx->eloop, ctx->udp_rfd, dhcp_handleudp, ctx);
3879         }
3880         if (!IN_PRIVSEP(ctx) && ctx->udp_wfd == -1) {
3881                 ctx->udp_wfd = xsocket(PF_INET, SOCK_RAW|SOCK_CXNB,IPPROTO_UDP);
3882                 if (ctx->udp_wfd == -1) {
3883                         logerr(__func__);
3884                         return;
3885                 }
3886         }
3887
3888         if (dhcp_init(ifp) == -1) {
3889                 logerr("%s: dhcp_init", ifp->name);
3890                 return;
3891         }
3892
3893         state = D_STATE(ifp);
3894         clock_gettime(CLOCK_MONOTONIC, &state->started);
3895         state->interval = 0;
3896         free(state->offer);
3897         state->offer = NULL;
3898         state->offer_len = 0;
3899
3900 #ifdef ARPING
3901         if (ifo->arping_len && state->arping_index < ifo->arping_len) {
3902                 dhcp_arping(ifp);
3903                 return;
3904         }
3905 #endif
3906
3907         if (ifo->options & DHCPCD_STATIC) {
3908                 dhcp_static(ifp);
3909                 return;
3910         }
3911
3912         if (ifo->options & DHCPCD_INFORM) {
3913                 dhcp_inform(ifp);
3914                 return;
3915         }
3916
3917         /* We don't want to read the old lease if we NAK an old test */
3918         nolease = state->offer && ifp->ctx->options & DHCPCD_TEST;
3919         if (!nolease && ifo->options & DHCPCD_DHCP) {
3920                 state->offer_len = read_lease(ifp, &state->offer);
3921                 /* Check the saved lease matches the type we want */
3922                 if (state->offer) {
3923 #ifdef IN_IFF_DUPLICATED
3924                         struct in_addr addr;
3925                         struct ipv4_addr *ia;
3926
3927                         addr.s_addr = state->offer->yiaddr;
3928                         ia = ipv4_iffindaddr(ifp, &addr, NULL);
3929 #endif
3930
3931                         if ((!IS_DHCP(state->offer) &&
3932                             !(ifo->options & DHCPCD_BOOTP)) ||
3933 #ifdef IN_IFF_DUPLICATED
3934                             (ia && ia->addr_flags & IN_IFF_DUPLICATED) ||
3935 #endif
3936                             (IS_DHCP(state->offer) &&
3937                             ifo->options & DHCPCD_BOOTP))
3938                         {
3939                                 free(state->offer);
3940                                 state->offer = NULL;
3941                                 state->offer_len = 0;
3942                         }
3943                 }
3944         }
3945         if (state->offer) {
3946                 struct ipv4_addr *ia;
3947                 time_t mtime;
3948
3949                 get_lease(ifp, &state->lease, state->offer, state->offer_len);
3950                 state->lease.frominfo = 1;
3951                 if (state->new == NULL &&
3952                     (ia = ipv4_iffindaddr(ifp,
3953                     &state->lease.addr, &state->lease.mask)) != NULL)
3954                 {
3955                         /* We still have the IP address from the last lease.
3956                          * Fake add the address and routes from it so the lease
3957                          * can be cleaned up. */
3958                         state->new = malloc(state->offer_len);
3959                         if (state->new) {
3960                                 memcpy(state->new,
3961                                     state->offer, state->offer_len);
3962                                 state->new_len = state->offer_len;
3963                                 state->addr = ia;
3964                                 state->added |= STATE_ADDED | STATE_FAKE;
3965                                 rt_build(ifp->ctx, AF_INET);
3966                         } else
3967                                 logerr(__func__);
3968                 }
3969                 if (!IS_DHCP(state->offer)) {
3970                         free(state->offer);
3971                         state->offer = NULL;
3972                         state->offer_len = 0;
3973                 } else if (!(ifo->options & DHCPCD_LASTLEASE_EXTEND) &&
3974                     state->lease.leasetime != DHCP_INFINITE_LIFETIME &&
3975                     dhcp_filemtime(ifp->ctx, state->leasefile, &mtime) == 0)
3976                 {
3977                         time_t now;
3978
3979                         /* Offset lease times and check expiry */
3980                         now = time(NULL);
3981                         if (now == -1 ||
3982                             (time_t)state->lease.leasetime < now - mtime)
3983                         {
3984                                 logdebugx("%s: discarding expired lease",
3985                                     ifp->name);
3986                                 free(state->offer);
3987                                 state->offer = NULL;
3988                                 state->offer_len = 0;
3989                                 state->lease.addr.s_addr = 0;
3990                                 /* Technically we should discard the lease
3991                                  * as it's expired, just as DHCPv6 addresses
3992                                  * would be by the kernel.
3993                                  * However, this may violate POLA so
3994                                  * we currently leave it be.
3995                                  * If we get a totally different lease from
3996                                  * the DHCP server we'll drop it anyway, as
3997                                  * we will on any other event which would
3998                                  * trigger a lease drop.
3999                                  * This should only happen if dhcpcd stops
4000                                  * running and the lease expires before
4001                                  * dhcpcd starts again. */
4002 #if 0
4003                                 if (state->new)
4004                                         dhcp_drop(ifp, "EXPIRE");
4005 #endif
4006                         } else {
4007                                 l = (uint32_t)(now - mtime);
4008                                 state->lease.leasetime -= l;
4009                                 state->lease.renewaltime -= l;
4010                                 state->lease.rebindtime -= l;
4011                         }
4012                 }
4013         }
4014
4015 #ifdef IPV4LL
4016         if (!(ifo->options & DHCPCD_DHCP)) {
4017                 if (ifo->options & DHCPCD_IPV4LL)
4018                         ipv4ll_start(ifp);
4019                 return;
4020         }
4021 #endif
4022
4023         if (state->offer == NULL ||
4024             !IS_DHCP(state->offer) ||
4025             ifo->options & DHCPCD_ANONYMOUS)
4026                 dhcp_discover(ifp);
4027         else
4028                 dhcp_reboot(ifp);
4029 }
4030
4031 void
4032 dhcp_start(struct interface *ifp)
4033 {
4034         unsigned int delay;
4035 #ifdef ARPING
4036         const struct dhcp_state *state;
4037 #endif
4038
4039         if (!(ifp->options->options & DHCPCD_IPV4))
4040                 return;
4041
4042         /* If we haven't been given a netmask for our requested address,
4043          * set it now. */
4044         if (ifp->options->req_addr.s_addr != INADDR_ANY &&
4045             ifp->options->req_mask.s_addr == INADDR_ANY)
4046                 ifp->options->req_mask.s_addr =
4047                     ipv4_getnetmask(ifp->options->req_addr.s_addr);
4048
4049         /* If we haven't specified a ClientID and our hardware address
4050          * length is greater than BOOTP CHADDR then we enforce a ClientID
4051          * of the hardware address type and the hardware address.
4052          * If there is no hardware address and no ClientID set,
4053          * force a DUID based ClientID. */
4054         if (ifp->hwlen > 16)
4055                 ifp->options->options |= DHCPCD_CLIENTID;
4056         else if (ifp->hwlen == 0 && !(ifp->options->options & DHCPCD_CLIENTID))
4057                 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_DUID;
4058
4059         /* Firewire and InfiniBand interfaces require ClientID and
4060          * the broadcast option being set. */
4061         switch (ifp->hwtype) {
4062         case ARPHRD_IEEE1394:   /* FALLTHROUGH */
4063         case ARPHRD_INFINIBAND:
4064                 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_BROADCAST;
4065                 break;
4066         }
4067
4068         /* If we violate RFC2131 section 3.7 then require ARP
4069          * to detect if any other client wants our address. */
4070         if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND)
4071                 ifp->options->options |= DHCPCD_ARP;
4072
4073         /* No point in delaying a static configuration */
4074         if (ifp->options->options & DHCPCD_STATIC ||
4075             !(ifp->options->options & DHCPCD_INITIAL_DELAY))
4076         {
4077                 dhcp_start1(ifp);
4078                 return;
4079         }
4080
4081 #ifdef ARPING
4082         /* If we have arpinged then we have already delayed. */
4083         state = D_CSTATE(ifp);
4084         if (state != NULL && state->arping_index != -1) {
4085                 dhcp_start1(ifp);
4086                 return;
4087         }
4088 #endif
4089         delay = MSEC_PER_SEC +
4090                 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC);
4091         logdebugx("%s: delaying IPv4 for %0.1f seconds",
4092             ifp->name, (float)delay / MSEC_PER_SEC);
4093
4094         eloop_timeout_add_msec(ifp->ctx->eloop, delay, dhcp_start1, ifp);
4095 }
4096
4097 void
4098 dhcp_abort(struct interface *ifp)
4099 {
4100         struct dhcp_state *state;
4101
4102         state = D_STATE(ifp);
4103 #ifdef ARPING
4104         if (state != NULL)
4105                 state->arping_index = -1;
4106 #endif
4107
4108         eloop_timeout_delete(ifp->ctx->eloop, dhcp_start1, ifp);
4109
4110         if (state != NULL && state->added) {
4111                 rt_build(ifp->ctx, AF_INET);
4112 #ifdef ARP
4113                 if (ifp->options->options & DHCPCD_ARP)
4114                         arp_announceaddr(ifp->ctx, &state->addr->addr);
4115 #endif
4116         }
4117 }
4118
4119 struct ipv4_addr *
4120 dhcp_handleifa(int cmd, struct ipv4_addr *ia, pid_t pid)
4121 {
4122         struct interface *ifp;
4123         struct dhcp_state *state;
4124         struct if_options *ifo;
4125         uint8_t i;
4126
4127         ifp = ia->iface;
4128         state = D_STATE(ifp);
4129         if (state == NULL || state->state == DHS_NONE)
4130                 return ia;
4131
4132         if (cmd == RTM_DELADDR) {
4133                 if (state->addr == ia) {
4134                         loginfox("%s: pid %d deleted IP address %s",
4135                             ifp->name, pid, ia->saddr);
4136                         dhcp_close(ifp);
4137                         state->addr = NULL;
4138                         /* Don't clear the added state as we need
4139                          * to drop the lease. */
4140                         dhcp_drop(ifp, "EXPIRE");
4141                         dhcp_start1(ifp);
4142                         return ia;
4143                 }
4144         }
4145
4146         if (cmd != RTM_NEWADDR)
4147                 return ia;
4148
4149 #ifdef IN_IFF_NOTUSEABLE
4150         if (!(ia->addr_flags & IN_IFF_NOTUSEABLE))
4151                 dhcp_finish_dad(ifp, &ia->addr);
4152         else if (ia->addr_flags & IN_IFF_DUPLICATED)
4153                 return dhcp_addr_duplicated(ifp, &ia->addr) ? NULL : ia;
4154 #endif
4155
4156         ifo = ifp->options;
4157         if (ifo->options & DHCPCD_INFORM) {
4158                 if (state->state != DHS_INFORM)
4159                         dhcp_inform(ifp);
4160                 return ia;
4161         }
4162
4163         if (!(ifo->options & DHCPCD_STATIC))
4164                 return ia;
4165         if (ifo->req_addr.s_addr != INADDR_ANY)
4166                 return ia;
4167
4168         free(state->old);
4169         state->old = state->new;
4170         state->new_len = dhcp_message_new(&state->new, &ia->addr, &ia->mask);
4171         if (state->new == NULL)
4172                 return ia;
4173         if (ifp->flags & IFF_POINTOPOINT) {
4174                 for (i = 1; i < 255; i++)
4175                         if (i != DHO_ROUTER && has_option_mask(ifo->dstmask,i))
4176                                 dhcp_message_add_addr(state->new, i, ia->brd);
4177         }
4178         state->reason = "STATIC";
4179         rt_build(ifp->ctx, AF_INET);
4180         script_runreason(ifp, state->reason);
4181         if (ifo->options & DHCPCD_INFORM) {
4182                 state->state = DHS_INFORM;
4183                 dhcp_new_xid(ifp);
4184                 state->lease.server.s_addr = INADDR_ANY;
4185                 state->addr = ia;
4186                 dhcp_inform(ifp);
4187         }
4188
4189         return ia;
4190 }
4191
4192 #ifndef SMALL
4193 int
4194 dhcp_dump(struct interface *ifp)
4195 {
4196         struct dhcp_state *state;
4197
4198         ifp->if_data[IF_DATA_DHCP] = state = calloc(1, sizeof(*state));
4199         if (state == NULL) {
4200                 logerr(__func__);
4201                 return -1;
4202         }
4203         state->new_len = read_lease(ifp, &state->new);
4204         if (state->new == NULL) {
4205                 logerr("read_lease");
4206                 return -1;
4207         }
4208         state->reason = "DUMP";
4209         return script_runreason(ifp, state->reason);
4210 }
4211 #endif