src/dhcpv4.c

   1 /**
   2  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  *
  15  */
  16
  17 #include <time.h>
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <unistd.h>
  21 #include <stddef.h>
  22 #include <stdlib.h>
  23 #include <resolv.h>
  24 #include <limits.h>
  25 #include <net/if.h>
  26 #include <net/if_arp.h>
  27 #include <netinet/ip.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/timerfd.h>
  30 #include <arpa/inet.h>
  31
  32 #include <libubox/md5.h>
  33
  34 #include "odhcpd.h"
  35 #include "dhcpv4.h"
  36 #include "dhcpv6.h"
  37
  38 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
  39 static int setup_dhcpv4_addresses(struct interface *iface);
  40 static void update_static_assignments(struct interface *iface);
  41 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
  42 static void valid_until_cb(struct uloop_timeout *event);
  43 static void handle_addrlist_change(struct interface *iface);
  44 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a);
  45 static void dhcpv4_fr_start(struct dhcpv4_assignment *a);
  46 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a);
  47 static void handle_dhcpv4(void *addr, void *data, size_t len,
  48                 struct interface *iface, void *dest_addr);
  49 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
  50                 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
  51                 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
  52                 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid);
  53
  54 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
  55 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
  56 static uint32_t serial = 0;
  57
  58 struct odhcpd_ref_ip {
  59         struct list_head head;
  60         int ref_cnt;
  61         struct odhcpd_ipaddr addr;
  62 };
  63
  64 /* Create socket and register events */
  65 int dhcpv4_init(void)
  66 {
  67         uloop_timeout_set(&valid_until_timeout, 1000);
  68         netlink_add_netevent_handler(&dhcpv4_netevent_handler);
  69
  70         return 0;
  71 }
  72
  73 int dhcpv4_setup_interface(struct interface *iface, bool enable)
  74 {
  75         int ret = 0;
  76
  77         if (iface->dhcpv4_event.uloop.fd > 0) {
  78                 uloop_fd_delete(&iface->dhcpv4_event.uloop);
  79                 close(iface->dhcpv4_event.uloop.fd);
  80                 iface->dhcpv4_event.uloop.fd = -1;
  81         }
  82
  83         if (iface->dhcpv4 && enable) {
  84                 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
  85                                         {INADDR_ANY}, {0}};
  86                 int val = 1;
  87
  88                 if (!iface->dhcpv4_assignments.next)
  89                         INIT_LIST_HEAD(&iface->dhcpv4_assignments);
  90
  91                 if (!iface->dhcpv4_fr_ips.next)
  92                         INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
  93
  94                 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  95                 if (iface->dhcpv4_event.uloop.fd < 0) {
  96                         syslog(LOG_ERR, "socket(AF_INET): %m");
  97                         ret = -1;
  98                         goto out;
  99                 }
 100
 101                 /* Basic IPv4 configuration */
 102                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
 103                                         &val, sizeof(val)) < 0) {
 104                         syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
 105                         ret = -1;
 106                         goto out;
 107                 }
 108
 109                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
 110                                         &val, sizeof(val)) < 0) {
 111                         syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
 112                         ret = -1;
 113                         goto out;
 114                 }
 115
 116                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
 117                                         &val, sizeof(val)) < 0) {
 118                         syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
 119                         ret = -1;
 120                         goto out;
 121                 }
 122
 123                 val = IPTOS_PREC_INTERNETCONTROL;
 124                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
 125                                         &val, sizeof(val)) < 0) {
 126                         syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
 127                         ret = -1;
 128                         goto out;
 129                 }
 130
 131                 val = IP_PMTUDISC_DONT;
 132                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
 133                                         &val, sizeof(val)) < 0) {
 134                         syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
 135                         ret = -1;
 136                         goto out;
 137                 }
 138
 139                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 140                                         iface->ifname, strlen(iface->ifname)) < 0) {
 141                         syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 142                         ret = -1;
 143                         goto out;
 144                 }
 145
 146                 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
 147                                         sizeof(bind_addr)) < 0) {
 148                         syslog(LOG_ERR, "bind(): %m");
 149                         ret = -1;
 150                         goto out;
 151                 }
 152
 153                 if (setup_dhcpv4_addresses(iface) < 0) {
 154                         ret = -1;
 155                         goto out;
 156                 }
 157
 158                 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
 159                 odhcpd_register(&iface->dhcpv4_event);
 160
 161                 update_static_assignments(iface);
 162         } else if (iface->dhcpv4_assignments.next) {
 163                 while (!list_empty(&iface->dhcpv4_assignments))
 164                         free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
 165                                                         struct dhcpv4_assignment, head));
 166         }
 167
 168 out:
 169         if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
 170                 close(iface->dhcpv4_event.uloop.fd);
 171                 iface->dhcpv4_event.uloop.fd = -1;
 172         }
 173
 174         return ret;
 175 }
 176
 177
 178 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 179 {
 180         struct interface *iface = info->iface;
 181
 182         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 183                 return;
 184
 185         switch (event) {
 186         case NETEV_IFINDEX_CHANGE:
 187                 dhcpv4_setup_interface(iface, true);
 188                 break;
 189         case NETEV_ADDRLIST_CHANGE:
 190                 handle_addrlist_change(iface);
 191                 break;
 192         default:
 193                 break;
 194         }
 195 }
 196
 197 static struct dhcpv4_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 198 {
 199         struct dhcpv4_assignment *a;
 200
 201         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 202                 if (!memcmp(a->hwaddr, hwaddr, 6))
 203                         return a;
 204
 205         return NULL;
 206 }
 207
 208 static struct dhcpv4_assignment *find_assignment_by_addr(struct interface *iface, const uint32_t addr)
 209 {
 210         struct dhcpv4_assignment *a;
 211
 212         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 213                 if (a->addr == addr)
 214                         return a;
 215
 216         return NULL;
 217 }
 218
 219 static int setup_dhcpv4_addresses(struct interface *iface)
 220 {
 221         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 222         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 223         iface->dhcpv4_local.s_addr = INADDR_ANY;
 224         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 225         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 226
 227         /* Sanity checks */
 228         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 229             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 230             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 231                 syslog(LOG_ERR, "invalid DHCP range for %s", iface->name);
 232                 return -1;
 233         }
 234
 235         if (!iface->addr4_len) {
 236                 syslog(LOG_WARNING, "no network(s) available on %s", iface->name);
 237                 return -1;
 238         }
 239
 240         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 241         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 242
 243         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 244                 struct in_addr *addr = &iface->addr4[i].addr.in;
 245                 struct in_addr mask;
 246
 247                 if (addr_is_fr_ip(iface, addr))
 248                         continue;
 249
 250                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 251                 if ((start & ntohl(~mask.s_addr)) == start &&
 252                             (end & ntohl(~mask.s_addr)) == end) {
 253                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 254                                                         (addr->s_addr & mask.s_addr);
 255                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 256                                                         (addr->s_addr & mask.s_addr);
 257                         iface->dhcpv4_local = *addr;
 258                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 259                         iface->dhcpv4_mask = mask;
 260                         return 0;
 261                 }
 262         }
 263
 264         /* Don't allocate IP range for subnets bigger than 28 */
 265         if (iface->addr4[0].prefix > 28) {
 266                 syslog(LOG_WARNING, "auto allocation of DHCP range fails on %s", iface->name);
 267                 return -1;
 268         }
 269
 270         iface->dhcpv4_local = iface->addr4[0].addr.in;
 271         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 272         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 273         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 274
 275         /* Auto allocate ranges */
 276         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
 277                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 278                 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
 279         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
 280                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 281                 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
 282         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
 283                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 284                 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
 285         } else {
 286                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 287                 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
 288         }
 289
 290         return 0;
 291 }
 292
 293 static void update_static_assignments(struct interface *iface)
 294 {
 295         struct dhcpv4_assignment *a, *c;
 296
 297         /* Cleanup static entries not belonging to the network */
 298         list_for_each_entry_safe(a, c, &iface->dhcpv4_assignments, head) {
 299                 if ((a->flags & OAF_STATIC) &&
 300                                 ((a->addr & iface->dhcpv4_mask.s_addr) !=
 301                                  (iface->dhcpv4_start.s_addr & iface->dhcpv4_mask.s_addr)))
 302                         free_dhcpv4_assignment(a);
 303         }
 304
 305         /* Parse static entries */
 306         struct lease *lease;
 307         list_for_each_entry(lease, &leases, head) {
 308                 if ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 309                                 (lease->ipaddr.s_addr & iface->dhcpv4_mask.s_addr)) {
 310                         continue;
 311                 }
 312
 313                 a = find_assignment_by_hwaddr(iface, lease->mac.ether_addr_octet);
 314
 315                 if (!a) {
 316                         /* Check if there's an assignment with the specified IP address */
 317                         if (find_assignment_by_addr(iface, lease->ipaddr.s_addr))
 318                                 continue;
 319
 320                         /* Construct entry */
 321                         a = calloc(1, sizeof(*a));
 322                         if (!a) {
 323                                 syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
 324                                         iface->ifname);
 325                                 continue;
 326                         }
 327                         memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
 328                 }
 329
 330                 a->leasetime = lease->dhcpv4_leasetime;
 331
 332                 a->addr = lease->ipaddr.s_addr;
 333                 /* Static assignment */
 334                 a->flags |= OAF_STATIC;
 335                 /* Infinite valid */
 336                 a->valid_until = 0;
 337                 a->iface = iface;
 338                 if (lease->hostname[0]) {
 339                         free(a->hostname);
 340                         a->hostname = strdup(lease->hostname);
 341                 }
 342
 343                 /* Assign to all interfaces */
 344                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 345                         if (ntohl(c->addr) > ntohl(a->addr)) {
 346                                 list_add_tail(&a->head, &c->head);
 347                                 break;
 348                         }
 349                 }
 350
 351                 if (&c->head == &iface->dhcpv4_assignments)
 352                         list_add(&a->head, &iface->dhcpv4_assignments);
 353         }
 354 }
 355
 356 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 357 {
 358         *ptr = ip;
 359         ip->ref_cnt++;
 360 }
 361
 362 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 363 {
 364         struct odhcpd_ref_ip *ip = *ptr;
 365
 366         if (--ip->ref_cnt == 0) {
 367                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 368
 369                 list_del(&ip->head);
 370                 free(ip);
 371         }
 372
 373         *ptr = NULL;
 374 }
 375
 376 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 377 {
 378         struct odhcpd_ref_ip *p;
 379
 380         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 381                 if (addr->s_addr == p->addr.addr.in.s_addr)
 382                         return true;
 383         }
 384
 385         return false;
 386 }
 387
 388 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 389                                 uint32_t mask)
 390 {
 391         struct dhcpv4_assignment *a = NULL;
 392         struct odhcpd_ref_ip *fr_ip = NULL;
 393
 394         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 395                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 396                     !a->fr_ip &&
 397                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 398                         if (!fr_ip) {
 399                                 fr_ip = calloc(1, sizeof(*fr_ip));
 400                                 if (!fr_ip)
 401                                         break;
 402
 403                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 404                                 fr_ip->addr = *addr;
 405                         }
 406                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 407                 }
 408         }
 409
 410         return fr_ip ? true : false;
 411 }
 412
 413 static void valid_until_cb(struct uloop_timeout *event)
 414 {
 415         time_t now = odhcpd_time();
 416         struct interface *iface;
 417         list_for_each_entry(iface, &interfaces, head) {
 418                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 419                         continue;
 420
 421                 struct dhcpv4_assignment *a, *n;
 422                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 423                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 424                                 free_dhcpv4_assignment(a);
 425                 }
 426         }
 427         uloop_timeout_set(event, 1000);
 428 }
 429
 430 static void handle_addrlist_change(struct interface *iface)
 431 {
 432         struct odhcpd_ipaddr ip;
 433         struct odhcpd_ref_ip *a;
 434         struct dhcpv4_assignment *c;
 435         uint32_t mask = iface->dhcpv4_mask.s_addr;
 436
 437         memset(&ip, 0, sizeof(ip));
 438         ip.addr.in = iface->dhcpv4_local;
 439         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 440         ip.broadcast = iface->dhcpv4_bcast;
 441
 442         setup_dhcpv4_addresses(iface);
 443
 444         if ((ip.addr.in.s_addr & mask) ==
 445             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 446                 return;
 447
 448         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 449                 return;
 450
 451         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 452                 return;
 453
 454         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 455
 456         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 457                 syslog(LOG_ERR, "Failed to add ip address");
 458                 return;
 459         }
 460
 461         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 462                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 463                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 464                                 dhcpv4_fr_start(c);
 465                         else
 466                                 dhcpv4_fr_stop(c);
 467                 }
 468         }
 469 }
 470
 471 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 472 {
 473         switch (reqmsg) {
 474         case (DHCPV4_MSG_DISCOVER):
 475                 return "DHCPV4_MSG_DISCOVER";
 476         case (DHCPV4_MSG_OFFER):
 477                 return "DHCPV4_MSG_OFFER";
 478         case (DHCPV4_MSG_REQUEST):
 479                 return "DHCPV4_MSG_REQUEST";
 480         case (DHCPV4_MSG_DECLINE):
 481                 return "DHCPV4_MSG_DECLINE";
 482         case (DHCPV4_MSG_ACK):
 483                 return "DHCPV4_MSG_ACK";
 484         case (DHCPV4_MSG_NAK):
 485                 return "DHCPV4_MSG_NAK";
 486         case (DHCPV4_MSG_RELEASE):
 487                 return "DHCPV4_MSG_RELEASE";
 488         case (DHCPV4_MSG_INFORM):
 489                 return "DHCPV4_MSG_INFORM";
 490         case (DHCPV4_MSG_FORCERENEW):
 491                 return "DHCPV4_MSG_FORCERENEW";
 492         default:
 493                 return "UNKNOWN";
 494         }
 495 }
 496
 497 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
 498 {
 499         if (a->head.next)
 500                 list_del(&a->head);
 501
 502         if (a->fr_ip)
 503                 dhcpv4_fr_stop(a);
 504
 505         free(a->hostname);
 506         free(a);
 507 }
 508
 509 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 510                 uint8_t type, uint8_t len, const void *data)
 511 {
 512         uint8_t *c = *cookie;
 513         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 514
 515         if (*cookie + 2 + len > end)
 516                 return;
 517
 518         *c++ = type;
 519         *c++ = len;
 520         memcpy(c, data, len);
 521
 522         *cookie = c + len;
 523 }
 524
 525 static void dhcpv4_fr_send(struct dhcpv4_assignment *a)
 526 {
 527         struct dhcpv4_message fr_msg = {
 528                 .op = DHCPV4_BOOTREPLY,
 529                 .htype = 1,
 530                 .hlen = 6,
 531                 .hops = 0,
 532                 .secs = 0,
 533                 .flags = 0,
 534                 .ciaddr = {INADDR_ANY},
 535                 .yiaddr = {INADDR_ANY},
 536                 .siaddr = {INADDR_ANY},
 537                 .giaddr = {INADDR_ANY},
 538                 .chaddr = {0},
 539                 .sname = {0},
 540                 .file = {0},
 541         };
 542         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 543                 .protocol = 3,
 544                 .algorithm = 1,
 545                 .rdm = 0,
 546                 .replay = {htonl(time(NULL)), htonl(++serial)},
 547                 .type = 2,
 548                 .key = {0},
 549         };
 550         struct interface *iface = a->iface;
 551
 552         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 553         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 554
 555         fr_msg.options[0] = 0x63;
 556         fr_msg.options[1] = 0x82;
 557         fr_msg.options[2] = 0x53;
 558         fr_msg.options[3] = 0x63;
 559
 560         uint8_t *cookie = &fr_msg.options[4];
 561         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 562
 563         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 564         if (a->accept_fr_nonce) {
 565                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 566                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 567                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 568
 569                 md5_ctx_t md5;
 570                 uint8_t secretbytes[64];
 571                 memset(secretbytes, 0, sizeof(secretbytes));
 572                 memcpy(secretbytes, a->key, sizeof(a->key));
 573
 574                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 575                         secretbytes[i] ^= 0x36;
 576
 577                 md5_begin(&md5);
 578                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 579                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 580                 md5_end(auth_o->key, &md5);
 581
 582                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 583                         secretbytes[i] ^= 0x36;
 584                         secretbytes[i] ^= 0x5c;
 585                 }
 586
 587                 md5_begin(&md5);
 588                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 589                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 590                 md5_end(auth_o->key, &md5);
 591         } else {
 592                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 593                                 &a->fr_ip->addr.addr.in.s_addr);
 594                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 595         }
 596
 597         struct sockaddr_in dest;
 598         memset(&dest, 0, sizeof(dest));
 599         dest.sin_family = AF_INET;
 600         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 601         dest.sin_addr.s_addr = a->addr;
 602
 603         if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
 604                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
 605                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
 606                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 607         else
 608                 syslog(LOG_WARNING, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
 609                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 610 }
 611
 612 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 613 {
 614         struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
 615
 616         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 617                 dhcpv4_fr_send(a);
 618                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 619                 a->fr_cnt++;
 620         } else
 621                 dhcpv4_fr_stop(a);
 622 }
 623
 624 static void dhcpv4_fr_start(struct dhcpv4_assignment *a)
 625 {
 626         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 627         a->fr_timer.cb = dhcpv4_fr_timer;
 628         a->fr_cnt++;
 629
 630         dhcpv4_fr_send(a);
 631 }
 632
 633 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a)
 634 {
 635         uloop_timeout_cancel(&a->fr_timer);
 636         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 637         a->fr_cnt = 0;
 638         a->fr_timer.cb = NULL;
 639 }
 640
 641 /* Handler for DHCPv4 messages */
 642 static void handle_dhcpv4(void *addr, void *data, size_t len,
 643                 struct interface *iface, _unused void *dest_addr)
 644 {
 645         if (!iface->dhcpv4)
 646                 return;
 647
 648         struct dhcpv4_message *req = data;
 649         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 650                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 651                 return;
 652
 653
 654         syslog(LOG_NOTICE, "Got DHCPv4 request");
 655
 656         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 657                 syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
 658                 return;
 659         }
 660
 661         int sock = iface->dhcpv4_event.uloop.fd;
 662
 663         struct dhcpv4_message reply = {
 664                 .op = DHCPV4_BOOTREPLY,
 665                 .htype = req->htype,
 666                 .hlen = req->hlen,
 667                 .hops = 0,
 668                 .xid = req->xid,
 669                 .secs = 0,
 670                 .flags = req->flags,
 671                 .ciaddr = {INADDR_ANY},
 672                 .giaddr = req->giaddr,
 673                 .siaddr = iface->dhcpv4_local,
 674         };
 675         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 676
 677         reply.options[0] = 0x63;
 678         reply.options[1] = 0x82;
 679         reply.options[2] = 0x53;
 680         reply.options[3] = 0x63;
 681
 682         uint8_t *cookie = &reply.options[4];
 683         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 684         uint8_t msg = DHCPV4_MSG_ACK;
 685
 686         uint32_t reqaddr = INADDR_ANY;
 687         uint32_t leasetime = 0;
 688         size_t hostname_len = 0;
 689         char hostname[256];
 690         bool accept_fr_nonce = false;
 691         bool incl_fr_opt = false;
 692
 693         uint8_t *start = &req->options[4];
 694         uint8_t *end = ((uint8_t*)data) + len;
 695         struct dhcpv4_option *opt;
 696         dhcpv4_for_each_option(start, end, opt) {
 697                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 698                         reqmsg = opt->data[0];
 699                 else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 700                         hostname_len = opt->len;
 701                         memcpy(hostname, opt->data, hostname_len);
 702                         hostname[hostname_len] = 0;
 703                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 704                         memcpy(&reqaddr, opt->data, 4);
 705                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 706                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 707                                 return;
 708                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 709                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 710                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 711                                 size_t elen = strlen(iface->filter_class);
 712                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 713                                         return; // Ignore from homenet
 714                         }
 715                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 716                         memcpy(&leasetime, opt->data, 4);
 717                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 718                         for (uint8_t i = 0; i < opt->len; i++) {
 719                                 if (opt->data[i] == 1) {
 720                                         accept_fr_nonce = true;
 721                                         break;
 722                                 }
 723                         }
 724
 725                 }
 726         }
 727
 728         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 729                         reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 730                         reqmsg != DHCPV4_MSG_RELEASE)
 731                 return;
 732
 733         struct dhcpv4_assignment *lease = NULL;
 734         uint32_t serverid = iface->dhcpv4_local.s_addr;
 735         uint32_t fr_serverid = INADDR_ANY;
 736
 737         if (reqmsg != DHCPV4_MSG_INFORM)
 738                 lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 739                                         &leasetime, hostname, hostname_len,
 740                                         accept_fr_nonce, &incl_fr_opt, &fr_serverid);
 741
 742         if (!lease) {
 743                 if (reqmsg == DHCPV4_MSG_REQUEST)
 744                         msg = DHCPV4_MSG_NAK;
 745                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 746                         return;
 747         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 748                 msg = DHCPV4_MSG_OFFER;
 749         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 750                         ((reqaddr && reqaddr != lease->addr) ||
 751                          (req->ciaddr.s_addr && req->ciaddr.s_addr != lease->addr))) {
 752                 msg = DHCPV4_MSG_NAK;
 753                 /*
 754                  * DHCP client requested an IP which we can't offer to him. Probably the
 755                  * client changed the network or the network has been changed. The reply
 756                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 757                  *
 758                  * For modern devices we build an answer that includes a valid IP, like
 759                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 760                  * perform additional DHCP round trips.
 761                  *
 762                  */
 763
 764                 /*
 765                  *
 766                  * Buggy clients do serverid checking in nack messages; therefore set the
 767                  * serverid in nack messages triggered by a previous force renew equal to
 768                  * the server id in use at that time by the server
 769                  *
 770                  */
 771                 if (fr_serverid)
 772                         serverid = fr_serverid;
 773
 774                 if (req->ciaddr.s_addr &&
 775                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 776                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 777                         req->ciaddr.s_addr = INADDR_ANY;
 778         }
 779
 780         syslog(LOG_WARNING, "received %s from %s", dhcpv4_msg_to_string(reqmsg),
 781                         odhcpd_print_mac(req->chaddr, req->hlen));
 782
 783 #ifdef WITH_UBUS
 784         if (reqmsg == DHCPV4_MSG_RELEASE)
 785                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 786                                         &req->ciaddr, hostname, iface->ifname);
 787 #endif
 788         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 789                 return;
 790
 791         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 792         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 793
 794         if (lease) {
 795                 uint32_t val;
 796
 797                 reply.yiaddr.s_addr = lease->addr;
 798
 799                 val = htonl(leasetime);
 800                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 801
 802                 if (leasetime != UINT32_MAX) {
 803                         val = htonl(500 * leasetime / 1000);
 804                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 805
 806                         val = htonl(875 * leasetime / 1000);
 807                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 808                 }
 809
 810                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 811                                 &iface->dhcpv4_mask.s_addr);
 812
 813                 if (lease->hostname)
 814                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 815                                         strlen(lease->hostname), lease->hostname);
 816
 817                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 818                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 819
 820                 if (incl_fr_opt) {
 821                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 822                                 struct dhcpv4_auth_forcerenew auth = {
 823                                         .protocol = 3,
 824                                         .algorithm = 1,
 825                                         .rdm = 0,
 826                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 827                                         .type = 1,
 828                                         .key = {0},
 829                                 };
 830
 831                                 memcpy(auth.key, lease->key, sizeof(auth.key));
 832                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 833                         } else {
 834                                 uint8_t one = 1;
 835                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 836                                         sizeof(one), &one);
 837                         }
 838                 }
 839         }
 840
 841         struct ifreq ifr;
 842
 843         memset(&ifr, 0, sizeof(ifr));
 844         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 845
 846         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 847                 uint16_t mtu = htons(ifr.ifr_mtu);
 848                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 849         }
 850
 851         if (iface->search && iface->search_len <= 255)
 852                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 853                                 iface->search_len, iface->search);
 854         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 855                 uint8_t search_buf[256];
 856                 int len = dn_comp(_res.dnsrch[0], search_buf,
 857                                                 sizeof(search_buf), NULL, NULL);
 858                 if (len > 0)
 859                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 860                                         len, search_buf);
 861         }
 862
 863         if (iface->dhcpv4_router_cnt == 0)
 864                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 865         else
 866                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 867                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 868
 869
 870         if (iface->dhcpv4_dns_cnt == 0)
 871                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 872         else
 873                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 874                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 875
 876
 877         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 878
 879         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 880         if (req->giaddr.s_addr) {
 881                 /*
 882                  * relay agent is configured, send reply to the agent
 883                  */
 884                 dest.sin_addr = req->giaddr;
 885                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 886         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 887                 /*
 888                  * client has existing configuration (ciaddr is set) AND this address is
 889                  * not the address it used for the dhcp message
 890                  */
 891                 dest.sin_addr = req->ciaddr;
 892                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 893         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 894                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 895                 /*
 896                  * client requests a broadcast reply OR we can't offer an IP
 897                  */
 898                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 899                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 900         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 901                 /*
 902                  * client has no previous configuration -> no IP, so we need to reply
 903                  * with a broadcast packet
 904                  */
 905                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 906                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 907         } else {
 908                 /*
 909                  * send reply to the newly (in this proccess) allocated IP
 910                  */
 911                 dest.sin_addr = reply.yiaddr;
 912                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 913
 914                 struct arpreq arp = {.arp_flags = ATF_COM};
 915                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 916                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 917                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 918                 ioctl(sock, SIOCSARP, &arp);
 919         }
 920
 921
 922         if (sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
 923                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 924                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 925                         dhcpv4_msg_to_string(msg),
 926                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 927                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 928                         inet_ntoa(dest.sin_addr));
 929         else
 930                 syslog(LOG_ERR, "Sent %s to %s - %s",
 931                         dhcpv4_msg_to_string(msg),
 932                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 933                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 934                         inet_ntoa(dest.sin_addr));
 935
 936
 937 #ifdef WITH_UBUS
 938         if (msg == DHCPV4_MSG_ACK)
 939                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 940                                         hostname, iface->ifname);
 941 #endif
 942 }
 943
 944 static bool dhcpv4_assign(struct interface *iface,
 945                 struct dhcpv4_assignment *assign, uint32_t raddr)
 946 {
 947         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 948         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 949         uint32_t count = end - start + 1;
 950
 951         /* try to assign the IP the client asked for */
 952         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 953                         !find_assignment_by_addr(iface, raddr)) {
 954                 assign->addr = raddr;
 955                 syslog(LOG_INFO, "assigning the IP the client asked for: %u.%u.%u.%u",
 956                                 ((uint8_t *)&assign->addr)[0],
 957                                 ((uint8_t *)&assign->addr)[1],
 958                                 ((uint8_t *)&assign->addr)[2],
 959                                 ((uint8_t *)&assign->addr)[3]);
 960                 return true;
 961         }
 962
 963         /* Seed RNG with checksum of hwaddress */
 964         uint32_t seed = 0;
 965         for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) {
 966                 /* Knuth's multiplicative method */
 967                 uint8_t o = assign->hwaddr[i];
 968                 seed += (o*2654435761) % UINT32_MAX;
 969         }
 970
 971         srand(seed);
 972
 973         uint32_t try = (((uint32_t)rand()) % count) + start;
 974
 975         if (list_empty(&iface->dhcpv4_assignments)) {
 976                 assign->addr = htonl(try);
 977                 syslog(LOG_INFO, "assigning mapped IP (empty list): %u.%u.%u.%u",
 978                                 ((uint8_t *)&assign->addr)[0],
 979                                 ((uint8_t *)&assign->addr)[1],
 980                                 ((uint8_t *)&assign->addr)[2],
 981                                 ((uint8_t *)&assign->addr)[3]);
 982                 return true;
 983         }
 984
 985         for (uint32_t i = 0; i < count; ++i) {
 986                 if (!find_assignment_by_addr(iface, htonl(try))) {
 987                         /* test was successful: IP address is not assigned, assign it */
 988                         assign->addr = htonl(try);
 989                         syslog(LOG_DEBUG, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 990                                         ((uint8_t *)&assign->addr)[0],
 991                                         ((uint8_t *)&assign->addr)[1],
 992                                         ((uint8_t *)&assign->addr)[2],
 993                                         ((uint8_t *)&assign->addr)[3],
 994                                         i, count);
 995                         return true;
 996                 }
 997                 try = (((try - start) + 1) % count) + start;
 998         }
 999
1000         syslog(LOG_WARNING, "can't assign any IP address -> address space is full");
1001         return false;
1002 }
1003
1004
1005 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
1006                 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
1007                 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
1008                 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid)
1009 {
1010         struct dhcpv4_assignment *a = find_assignment_by_hwaddr(iface, mac);
1011         struct dhcpv4_assignment *lease = NULL;
1012         time_t now = odhcpd_time();
1013
1014         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1015                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1016                 dhcpv4_fr_stop(a);
1017         }
1018
1019         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1020                 bool assigned = !!a;
1021
1022                 if (!a) {
1023                         if (!iface->no_dynamic_dhcp) {
1024                                 /* Create new binding */
1025                                 a = calloc(1, sizeof(*a));
1026                                 if (!a) {
1027                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1028                                                         iface->ifname);
1029                                         return NULL;
1030                                 }
1031                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1032                                 /* Don't consider new assignment as infinite */
1033                                 a->valid_until = now;
1034
1035                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1036                                 if (assigned) {
1037                                         a->iface = iface;
1038                                         list_add(&a->head, &iface->dhcpv4_assignments);
1039                                 }
1040                         }
1041                 } else if ((a->addr & iface->dhcpv4_mask.s_addr) !=
1042                                 (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) {
1043                         list_del(&a->head);
1044
1045                         assigned = dhcpv4_assign(iface, a, reqaddr);
1046                         if (assigned)
1047                                 list_add(&a->head, &iface->dhcpv4_assignments);
1048                 }
1049
1050                 if (assigned) {
1051                         uint32_t my_leasetime;
1052
1053                         if (a->leasetime)
1054                                 my_leasetime = a->leasetime;
1055                         else
1056                                 my_leasetime = iface->dhcpv4_leasetime;
1057
1058                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1059                                 *leasetime = my_leasetime;
1060
1061                         if (msg == DHCPV4_MSG_DISCOVER) {
1062                                 a->flags &= ~OAF_BOUND;
1063
1064                                 *incl_fr_opt = accept_fr_nonce;
1065                                 if (!(a->flags & OAF_STATIC))
1066                                         a->valid_until = now;
1067                         } else {
1068                                 if (hostname_len > 0) {
1069                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1070                                         if (a->hostname) {
1071                                                 memcpy(a->hostname, hostname, hostname_len);
1072                                                 a->hostname[hostname_len] = 0;
1073                                         }
1074                                 }
1075
1076                                 if (!(a->flags & OAF_BOUND)) {
1077                                         a->accept_fr_nonce = accept_fr_nonce;
1078                                         *incl_fr_opt = accept_fr_nonce;
1079                                         odhcpd_urandom(a->key, sizeof(a->key));
1080                                         a->flags |= OAF_BOUND;
1081                                 } else
1082                                         *incl_fr_opt = false;
1083
1084                                 if (!(a->flags & OAF_STATIC))
1085                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1086                         }
1087                 } else if (!assigned && a) {
1088                         /* Cleanup failed assignment */
1089                         free_dhcpv4_assignment(a);
1090                         a = NULL;
1091                 }
1092
1093                 if (assigned && a)
1094                         lease = a;
1095         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1096                 a->flags &= ~OAF_BOUND;
1097
1098                 if (!(a->flags & OAF_STATIC))
1099                         a->valid_until = now - 1;
1100
1101         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1102                 a->flags &= ~OAF_BOUND;
1103
1104                 if (!(a->flags & OAF_STATIC)) {
1105                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1106                         a->valid_until = now + 3600; /* Block address for 1h */
1107                 }
1108         }
1109
1110         dhcpv6_write_statefile();
1111
1112         return lease;
1113 }