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 void valid_until_cb(struct uloop_timeout *event);
  42 static void handle_addrlist_change(struct interface *iface);
  43 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a);
  44 static void dhcpv4_fr_start(struct dhcpv4_assignment *a);
  45 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a);
  46 static void handle_dhcpv4(void *addr, void *data, size_t len,
  47                 struct interface *iface, void *dest_addr);
  48 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
  49                 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
  50                 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
  51                 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid);
  52
  53 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
  54 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
  55 static uint32_t serial = 0;
  56
  57 struct odhcpd_ref_ip {
  58         struct list_head head;
  59         int ref_cnt;
  60         struct odhcpd_ipaddr addr;
  61 };
  62
  63 /* Create socket and register events */
  64 int dhcpv4_init(void)
  65 {
  66         uloop_timeout_set(&valid_until_timeout, 1000);
  67         netlink_add_netevent_handler(&dhcpv4_netevent_handler);
  68
  69         return 0;
  70 }
  71
  72 int dhcpv4_setup_interface(struct interface *iface, bool enable)
  73 {
  74         int ret = 0;
  75
  76         if (iface->dhcpv4_event.uloop.fd > 0) {
  77                 uloop_fd_delete(&iface->dhcpv4_event.uloop);
  78                 close(iface->dhcpv4_event.uloop.fd);
  79                 iface->dhcpv4_event.uloop.fd = -1;
  80         }
  81
  82         if (iface->dhcpv4 && enable) {
  83                 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
  84                                         {INADDR_ANY}, {0}};
  85                 int val = 1;
  86
  87                 if (!iface->dhcpv4_assignments.next)
  88                         INIT_LIST_HEAD(&iface->dhcpv4_assignments);
  89
  90                 if (!iface->dhcpv4_fr_ips.next)
  91                         INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
  92
  93                 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  94                 if (iface->dhcpv4_event.uloop.fd < 0) {
  95                         syslog(LOG_ERR, "socket(AF_INET): %m");
  96                         ret = -1;
  97                         goto out;
  98                 }
  99
 100                 /* Basic IPv4 configuration */
 101                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
 102                                         &val, sizeof(val)) < 0) {
 103                         syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
 104                         ret = -1;
 105                         goto out;
 106                 }
 107
 108                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
 109                                         &val, sizeof(val)) < 0) {
 110                         syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
 111                         ret = -1;
 112                         goto out;
 113                 }
 114
 115                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
 116                                         &val, sizeof(val)) < 0) {
 117                         syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
 118                         ret = -1;
 119                         goto out;
 120                 }
 121
 122                 val = IPTOS_PREC_INTERNETCONTROL;
 123                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
 124                                         &val, sizeof(val)) < 0) {
 125                         syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
 126                         ret = -1;
 127                         goto out;
 128                 }
 129
 130                 val = IP_PMTUDISC_DONT;
 131                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
 132                                         &val, sizeof(val)) < 0) {
 133                         syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
 134                         ret = -1;
 135                         goto out;
 136                 }
 137
 138                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 139                                         iface->ifname, strlen(iface->ifname)) < 0) {
 140                         syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 141                         ret = -1;
 142                         goto out;
 143                 }
 144
 145                 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
 146                                         sizeof(bind_addr)) < 0) {
 147                         syslog(LOG_ERR, "bind(): %m");
 148                         ret = -1;
 149                         goto out;
 150                 }
 151
 152                 if (setup_dhcpv4_addresses(iface) < 0) {
 153                         ret = -1;
 154                         goto out;
 155                 }
 156
 157                 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
 158                 odhcpd_register(&iface->dhcpv4_event);
 159
 160                 update_static_assignments(iface);
 161         } else if (iface->dhcpv4_assignments.next) {
 162                 while (!list_empty(&iface->dhcpv4_assignments))
 163                         free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
 164                                                         struct dhcpv4_assignment, head));
 165         }
 166
 167 out:
 168         if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
 169                 close(iface->dhcpv4_event.uloop.fd);
 170                 iface->dhcpv4_event.uloop.fd = -1;
 171         }
 172
 173         return ret;
 174 }
 175
 176
 177 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 178 {
 179         struct interface *iface = info->iface;
 180
 181         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 182                 return;
 183
 184         switch (event) {
 185         case NETEV_IFINDEX_CHANGE:
 186                 dhcpv4_setup_interface(iface, true);
 187                 break;
 188         case NETEV_ADDRLIST_CHANGE:
 189                 handle_addrlist_change(iface);
 190                 break;
 191         default:
 192                 break;
 193         }
 194 }
 195
 196 static struct dhcpv4_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 197 {
 198         struct dhcpv4_assignment *a;
 199
 200         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 201                 if (!memcmp(a->hwaddr, hwaddr, 6))
 202                         return a;
 203
 204         return NULL;
 205 }
 206
 207 static struct dhcpv4_assignment *find_assignment_by_addr(struct interface *iface, const uint32_t addr)
 208 {
 209         struct dhcpv4_assignment *a;
 210
 211         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 212                 if (a->addr == addr)
 213                         return a;
 214
 215         return NULL;
 216 }
 217
 218 static int setup_dhcpv4_addresses(struct interface *iface)
 219 {
 220         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 221         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 222         iface->dhcpv4_local.s_addr = INADDR_ANY;
 223         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 224         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 225
 226         /* Sanity checks */
 227         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 228             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 229             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 230                 syslog(LOG_ERR, "invalid DHCP range for %s", iface->name);
 231                 return -1;
 232         }
 233
 234         if (!iface->addr4_len) {
 235                 syslog(LOG_WARNING, "no network(s) available on %s", iface->name);
 236                 return -1;
 237         }
 238
 239         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 240         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 241
 242         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 243                 struct in_addr *addr = &iface->addr4[i].addr.in;
 244                 struct in_addr mask;
 245
 246                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 247                 if ((start & ntohl(~mask.s_addr)) == start &&
 248                             (end & ntohl(~mask.s_addr)) == end) {
 249                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 250                                                         (addr->s_addr & mask.s_addr);
 251                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 252                                                         (addr->s_addr & mask.s_addr);
 253                         iface->dhcpv4_local = *addr;
 254                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 255                         iface->dhcpv4_mask = mask;
 256                         return 0;
 257                 }
 258         }
 259
 260         /* Don't allocate IP range for subnets bigger than 28 */
 261         if (iface->addr4[0].prefix > 28) {
 262                 syslog(LOG_WARNING, "auto allocation of DHCP range fails on %s", iface->name);
 263                 return -1;
 264         }
 265
 266         iface->dhcpv4_local = iface->addr4[0].addr.in;
 267         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 268         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 269         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 270
 271         /* Auto allocate ranges */
 272         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
 273                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 274                 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
 275         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
 276                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 277                 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
 278         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
 279                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 280                 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
 281         } else {
 282                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 283                 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
 284         }
 285
 286         return 0;
 287 }
 288
 289 static void update_static_assignments(struct interface *iface)
 290 {
 291         struct dhcpv4_assignment *a, *c;
 292
 293         /* Cleanup static entries not belonging to the network */
 294         list_for_each_entry_safe(a, c, &iface->dhcpv4_assignments, head) {
 295                 if ((a->flags & OAF_STATIC) &&
 296                                 ((a->addr & iface->dhcpv4_mask.s_addr) !=
 297                                  (iface->dhcpv4_start.s_addr & iface->dhcpv4_mask.s_addr)))
 298                         free_dhcpv4_assignment(a);
 299         }
 300
 301         /* Parse static entries */
 302         struct lease *lease;
 303         list_for_each_entry(lease, &leases, head) {
 304                 if ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 305                                 (lease->ipaddr.s_addr & iface->dhcpv4_mask.s_addr)) {
 306                         continue;
 307                 }
 308
 309                 a = find_assignment_by_hwaddr(iface, lease->mac.ether_addr_octet);
 310
 311                 if (!a) {
 312                         /* Check if there's an assignment with the specified IP address */
 313                         if (find_assignment_by_addr(iface, lease->ipaddr.s_addr))
 314                                 continue;
 315
 316                         /* Construct entry */
 317                         a = calloc(1, sizeof(*a));
 318                         if (!a) {
 319                                 syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
 320                                         iface->ifname);
 321                                 continue;
 322                         }
 323                         memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
 324                 }
 325
 326                 a->leasetime = lease->dhcpv4_leasetime;
 327
 328                 a->addr = lease->ipaddr.s_addr;
 329                 /* Static assignment */
 330                 a->flags |= OAF_STATIC;
 331                 /* Infinite valid */
 332                 a->valid_until = 0;
 333                 a->iface = iface;
 334                 if (lease->hostname[0]) {
 335                         free(a->hostname);
 336                         a->hostname = strdup(lease->hostname);
 337                 }
 338
 339                 /* Assign to all interfaces */
 340                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 341                         if (ntohl(c->addr) > ntohl(a->addr)) {
 342                                 list_add_tail(&a->head, &c->head);
 343                                 break;
 344                         }
 345                 }
 346
 347                 if (&c->head == &iface->dhcpv4_assignments)
 348                         list_add(&a->head, &iface->dhcpv4_assignments);
 349         }
 350 }
 351
 352 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 353 {
 354         *ptr = ip;
 355         ip->ref_cnt++;
 356 }
 357
 358 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 359 {
 360         struct odhcpd_ref_ip *ip = *ptr;
 361
 362         if (--ip->ref_cnt == 0) {
 363                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 364
 365                 list_del(&ip->head);
 366                 free(ip);
 367         }
 368
 369         *ptr = NULL;
 370 }
 371
 372 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 373                                 uint32_t mask)
 374 {
 375         struct dhcpv4_assignment *a = NULL;
 376         struct odhcpd_ref_ip *fr_ip = NULL;
 377
 378         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 379                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 380                     !a->fr_ip &&
 381                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 382                         if (!fr_ip) {
 383                                 fr_ip = calloc(1, sizeof(*fr_ip));
 384                                 if (!fr_ip)
 385                                         break;
 386
 387                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 388                                 fr_ip->addr = *addr;
 389                         }
 390                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 391                 }
 392         }
 393
 394         return fr_ip ? true : false;
 395 }
 396
 397 static void valid_until_cb(struct uloop_timeout *event)
 398 {
 399         time_t now = odhcpd_time();
 400         struct interface *iface;
 401         list_for_each_entry(iface, &interfaces, head) {
 402                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 403                         continue;
 404
 405                 struct dhcpv4_assignment *a, *n;
 406                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 407                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 408                                 free_dhcpv4_assignment(a);
 409                 }
 410         }
 411         uloop_timeout_set(event, 1000);
 412 }
 413
 414 static void handle_addrlist_change(struct interface *iface)
 415 {
 416         struct odhcpd_ipaddr ip;
 417         struct odhcpd_ref_ip *a;
 418         struct dhcpv4_assignment *c;
 419         uint32_t mask = iface->dhcpv4_mask.s_addr;
 420
 421         memset(&ip, 0, sizeof(ip));
 422         ip.addr.in = iface->dhcpv4_local;
 423         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 424         ip.broadcast = iface->dhcpv4_bcast;
 425
 426         setup_dhcpv4_addresses(iface);
 427
 428         if ((ip.addr.in.s_addr & mask) ==
 429             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 430                 return;
 431
 432         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 433                 return;
 434
 435         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 436                 return;
 437
 438         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 439
 440         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 441                 syslog(LOG_ERR, "Failed to add ip address");
 442                 return;
 443         }
 444
 445         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 446                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 447                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 448                                 dhcpv4_fr_start(c);
 449                         else
 450                                 dhcpv4_fr_stop(c);
 451                 }
 452         }
 453 }
 454
 455 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 456 {
 457         switch (reqmsg) {
 458         case (DHCPV4_MSG_DISCOVER):
 459                 return "DHCPV4_MSG_DISCOVER";
 460         case (DHCPV4_MSG_OFFER):
 461                 return "DHCPV4_MSG_OFFER";
 462         case (DHCPV4_MSG_REQUEST):
 463                 return "DHCPV4_MSG_REQUEST";
 464         case (DHCPV4_MSG_DECLINE):
 465                 return "DHCPV4_MSG_DECLINE";
 466         case (DHCPV4_MSG_ACK):
 467                 return "DHCPV4_MSG_ACK";
 468         case (DHCPV4_MSG_NAK):
 469                 return "DHCPV4_MSG_NAK";
 470         case (DHCPV4_MSG_RELEASE):
 471                 return "DHCPV4_MSG_RELEASE";
 472         case (DHCPV4_MSG_INFORM):
 473                 return "DHCPV4_MSG_INFORM";
 474         case (DHCPV4_MSG_FORCERENEW):
 475                 return "DHCPV4_MSG_FORCERENEW";
 476         default:
 477                 return "UNKNOWN";
 478         }
 479 }
 480
 481 static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
 482 {
 483         if (a->head.next)
 484                 list_del(&a->head);
 485
 486         if (a->fr_ip)
 487                 dhcpv4_fr_stop(a);
 488
 489         free(a->hostname);
 490         free(a);
 491 }
 492
 493 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 494                 uint8_t type, uint8_t len, const void *data)
 495 {
 496         uint8_t *c = *cookie;
 497         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 498
 499         if (*cookie + 2 + len > end)
 500                 return;
 501
 502         *c++ = type;
 503         *c++ = len;
 504         memcpy(c, data, len);
 505
 506         *cookie = c + len;
 507 }
 508
 509 static void dhcpv4_fr_send(struct dhcpv4_assignment *a)
 510 {
 511         struct dhcpv4_message fr_msg = {
 512                 .op = DHCPV4_BOOTREPLY,
 513                 .htype = 1,
 514                 .hlen = 6,
 515                 .hops = 0,
 516                 .secs = 0,
 517                 .flags = 0,
 518                 .ciaddr = {INADDR_ANY},
 519                 .yiaddr = {INADDR_ANY},
 520                 .siaddr = {INADDR_ANY},
 521                 .giaddr = {INADDR_ANY},
 522                 .chaddr = {0},
 523                 .sname = {0},
 524                 .file = {0},
 525         };
 526         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 527                 .protocol = 3,
 528                 .algorithm = 1,
 529                 .rdm = 0,
 530                 .replay = {htonl(time(NULL)), htonl(++serial)},
 531                 .type = 2,
 532                 .key = {0},
 533         };
 534         struct interface *iface = a->iface;
 535
 536         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 537         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 538
 539         fr_msg.options[0] = 0x63;
 540         fr_msg.options[1] = 0x82;
 541         fr_msg.options[2] = 0x53;
 542         fr_msg.options[3] = 0x63;
 543
 544         uint8_t *cookie = &fr_msg.options[4];
 545         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 546
 547         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 548         if (a->accept_fr_nonce) {
 549                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 550                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 551                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 552
 553                 md5_ctx_t md5;
 554                 uint8_t secretbytes[64];
 555                 memset(secretbytes, 0, sizeof(secretbytes));
 556                 memcpy(secretbytes, a->key, sizeof(a->key));
 557
 558                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 559                         secretbytes[i] ^= 0x36;
 560
 561                 md5_begin(&md5);
 562                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 563                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 564                 md5_end(auth_o->key, &md5);
 565
 566                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 567                         secretbytes[i] ^= 0x36;
 568                         secretbytes[i] ^= 0x5c;
 569                 }
 570
 571                 md5_begin(&md5);
 572                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 573                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 574                 md5_end(auth_o->key, &md5);
 575         } else {
 576                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 577                                 &a->fr_ip->addr.addr.in.s_addr);
 578                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 579         }
 580
 581         struct sockaddr_in dest;
 582         memset(&dest, 0, sizeof(dest));
 583         dest.sin_family = AF_INET;
 584         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 585         dest.sin_addr.s_addr = a->addr;
 586
 587         syslog(LOG_WARNING, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
 588                         dhcpv4_msg_to_string(msg),
 589                         a->hwaddr[0], a->hwaddr[1], a->hwaddr[2],
 590                         a->hwaddr[3], a->hwaddr[4], a->hwaddr[5],
 591                         inet_ntoa(dest.sin_addr));
 592
 593         sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
 594                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
 595 }
 596
 597 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 598 {
 599         struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
 600
 601         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 602                 dhcpv4_fr_send(a);
 603                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 604                 a->fr_cnt++;
 605         } else
 606                 dhcpv4_fr_stop(a);
 607 }
 608
 609 static void dhcpv4_fr_start(struct dhcpv4_assignment *a)
 610 {
 611         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 612         a->fr_timer.cb = dhcpv4_fr_timer;
 613         a->fr_cnt++;
 614
 615         dhcpv4_fr_send(a);
 616 }
 617
 618 static void dhcpv4_fr_stop(struct dhcpv4_assignment *a)
 619 {
 620         uloop_timeout_cancel(&a->fr_timer);
 621         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 622         a->fr_cnt = 0;
 623         a->fr_timer.cb = NULL;
 624 }
 625
 626 // Handler for DHCPv4 messages
 627 static void handle_dhcpv4(void *addr, void *data, size_t len,
 628                 struct interface *iface, _unused void *dest_addr)
 629 {
 630         if (!iface->dhcpv4)
 631                 return;
 632
 633         struct dhcpv4_message *req = data;
 634         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 635                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 636                 return;
 637
 638
 639         syslog(LOG_NOTICE, "Got DHCPv4 request");
 640
 641         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 642                 syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
 643                 return;
 644         }
 645
 646         int sock = iface->dhcpv4_event.uloop.fd;
 647
 648         struct dhcpv4_message reply = {
 649                 .op = DHCPV4_BOOTREPLY,
 650                 .htype = req->htype,
 651                 .hlen = req->hlen,
 652                 .hops = 0,
 653                 .xid = req->xid,
 654                 .secs = 0,
 655                 .flags = req->flags,
 656                 .ciaddr = {INADDR_ANY},
 657                 .giaddr = req->giaddr,
 658                 .siaddr = iface->dhcpv4_local,
 659         };
 660         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 661
 662         reply.options[0] = 0x63;
 663         reply.options[1] = 0x82;
 664         reply.options[2] = 0x53;
 665         reply.options[3] = 0x63;
 666
 667         uint8_t *cookie = &reply.options[4];
 668         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 669         uint8_t msg = DHCPV4_MSG_ACK;
 670
 671         uint32_t reqaddr = INADDR_ANY;
 672         uint32_t leasetime = 0;
 673         size_t hostname_len = 0;
 674         char hostname[256];
 675         bool accept_fr_nonce = false;
 676         bool incl_fr_opt = false;
 677
 678         uint8_t *start = &req->options[4];
 679         uint8_t *end = ((uint8_t*)data) + len;
 680         struct dhcpv4_option *opt;
 681         dhcpv4_for_each_option(start, end, opt) {
 682                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 683                         reqmsg = opt->data[0];
 684                 else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 685                         hostname_len = opt->len;
 686                         memcpy(hostname, opt->data, hostname_len);
 687                         hostname[hostname_len] = 0;
 688                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 689                         memcpy(&reqaddr, opt->data, 4);
 690                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 691                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 692                                 return;
 693                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 694                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 695                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 696                                 size_t elen = strlen(iface->filter_class);
 697                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 698                                         return; // Ignore from homenet
 699                         }
 700                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 701                         memcpy(&leasetime, opt->data, 4);
 702                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 703                         for (uint8_t i = 0; i < opt->len; i++) {
 704                                 if (opt->data[i] == 1) {
 705                                         accept_fr_nonce = true;
 706                                         break;
 707                                 }
 708                         }
 709
 710                 }
 711         }
 712
 713         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 714                         reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 715                         reqmsg != DHCPV4_MSG_RELEASE)
 716                 return;
 717
 718         struct dhcpv4_assignment *lease = NULL;
 719         uint32_t serverid = iface->dhcpv4_local.s_addr;
 720         uint32_t fr_serverid = INADDR_ANY;
 721
 722         if (reqmsg != DHCPV4_MSG_INFORM)
 723                 lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 724                                         &leasetime, hostname, hostname_len,
 725                                         accept_fr_nonce, &incl_fr_opt, &fr_serverid);
 726
 727         if (!lease) {
 728                 if (reqmsg == DHCPV4_MSG_REQUEST)
 729                         msg = DHCPV4_MSG_NAK;
 730                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 731                         return;
 732         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 733                 msg = DHCPV4_MSG_OFFER;
 734         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 735                         ((reqaddr && reqaddr != lease->addr) ||
 736                          (req->ciaddr.s_addr && req->ciaddr.s_addr != lease->addr))) {
 737                 msg = DHCPV4_MSG_NAK;
 738                 /*
 739                  * DHCP client requested an IP which we can't offer to him. Probably the
 740                  * client changed the network or the network has been changed. The reply
 741                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 742                  *
 743                  * For modern devices we build an answer that includes a valid IP, like
 744                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 745                  * perform additional DHCP round trips.
 746                  *
 747                  */
 748
 749                 /*
 750                  *
 751                  * Buggy clients do serverid checking in nack messages; therefore set the
 752                  * serverid in nack messages triggered by a previous force renew equal to
 753                  * the server id in use at that time by the server
 754                  *
 755                  */
 756                 if (fr_serverid)
 757                         serverid = fr_serverid;
 758
 759                 if (req->ciaddr.s_addr &&
 760                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 761                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 762                         req->ciaddr.s_addr = INADDR_ANY;
 763         }
 764
 765         syslog(LOG_WARNING, "received %s from %02x:%02x:%02x:%02x:%02x:%02x",
 766                         dhcpv4_msg_to_string(reqmsg),
 767                         req->chaddr[0],req->chaddr[1],req->chaddr[2],
 768                         req->chaddr[3],req->chaddr[4],req->chaddr[5]);
 769
 770 #ifdef WITH_UBUS
 771         if (reqmsg == DHCPV4_MSG_RELEASE)
 772                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 773                                         &req->ciaddr, hostname, iface->ifname);
 774 #endif
 775         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 776                 return;
 777
 778         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 779         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 780
 781         if (lease) {
 782                 uint32_t val;
 783
 784                 reply.yiaddr.s_addr = lease->addr;
 785
 786                 val = htonl(leasetime);
 787                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 788
 789                 if (leasetime != UINT32_MAX) {
 790                         val = htonl(500 * leasetime / 1000);
 791                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 792
 793                         val = htonl(875 * leasetime / 1000);
 794                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 795                 }
 796
 797                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 798                                 &iface->dhcpv4_mask.s_addr);
 799
 800                 if (lease->hostname)
 801                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 802                                         strlen(lease->hostname), lease->hostname);
 803
 804                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 805                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 806
 807                 if (incl_fr_opt) {
 808                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 809                                 struct dhcpv4_auth_forcerenew auth = {
 810                                         .protocol = 3,
 811                                         .algorithm = 1,
 812                                         .rdm = 0,
 813                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 814                                         .type = 1,
 815                                         .key = {0},
 816                                 };
 817
 818                                 memcpy(auth.key, lease->key, sizeof(auth.key));
 819                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 820                         } else {
 821                                 uint8_t one = 1;
 822                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 823                                         sizeof(one), &one);
 824                         }
 825                 }
 826         }
 827
 828         struct ifreq ifr;
 829
 830         memset(&ifr, 0, sizeof(ifr));
 831         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 832
 833         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 834                 uint16_t mtu = htons(ifr.ifr_mtu);
 835                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 836         }
 837
 838         if (iface->search && iface->search_len <= 255)
 839                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 840                                 iface->search_len, iface->search);
 841         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 842                 uint8_t search_buf[256];
 843                 int len = dn_comp(_res.dnsrch[0], search_buf,
 844                                                 sizeof(search_buf), NULL, NULL);
 845                 if (len > 0)
 846                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 847                                         len, search_buf);
 848         }
 849
 850         if (iface->dhcpv4_router_cnt == 0)
 851                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 852         else
 853                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 854                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 855
 856
 857         if (iface->dhcpv4_dns_cnt == 0)
 858                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 859         else
 860                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 861                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 862
 863
 864         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 865
 866         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 867         if (req->giaddr.s_addr) {
 868                 /*
 869                  * relay agent is configured, send reply to the agent
 870                  */
 871                 dest.sin_addr = req->giaddr;
 872                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 873         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 874                 /*
 875                  * client has existing configuration (ciaddr is set) AND this address is
 876                  * not the address it used for the dhcp message
 877                  */
 878                 dest.sin_addr = req->ciaddr;
 879                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 880         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 881                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 882                 /*
 883                  * client requests a broadcast reply OR we can't offer an IP
 884                  */
 885                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 886                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 887         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 888                 /*
 889                  * client has no previous configuration -> no IP, so we need to reply
 890                  * with a broadcast packet
 891                  */
 892                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 893                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 894         } else {
 895                 /*
 896                  * send reply to the newly (in this proccess) allocated IP
 897                  */
 898                 dest.sin_addr = reply.yiaddr;
 899                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 900
 901                 struct arpreq arp = {.arp_flags = ATF_COM};
 902                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 903                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 904                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 905                 ioctl(sock, SIOCSARP, &arp);
 906         }
 907
 908         if (dest.sin_addr.s_addr == INADDR_BROADCAST)
 909                 /* reply goes to IP broadcast -> MAC broadcast */
 910                 syslog(LOG_WARNING, "sending %s to ff:ff:ff:ff:ff:ff - %s",
 911                                 dhcpv4_msg_to_string(msg),
 912                                 inet_ntoa(dest.sin_addr));
 913         else
 914                 /*
 915                  * reply is send directly to IP,
 916                  * MAC is assumed to be the same as the request
 917                  */
 918                 syslog(LOG_WARNING, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %s",
 919                                 dhcpv4_msg_to_string(msg),
 920                                 req->chaddr[0],req->chaddr[1],req->chaddr[2],
 921                                 req->chaddr[3],req->chaddr[4],req->chaddr[5],
 922                                 inet_ntoa(dest.sin_addr));
 923
 924         sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
 925                         (struct sockaddr*)&dest, sizeof(dest));
 926
 927 #ifdef WITH_UBUS
 928         if (msg == DHCPV4_MSG_ACK)
 929                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 930                                         hostname, iface->ifname);
 931 #endif
 932 }
 933
 934 static bool dhcpv4_assign(struct interface *iface,
 935                 struct dhcpv4_assignment *assign, uint32_t raddr)
 936 {
 937         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 938         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 939         uint32_t count = end - start + 1;
 940
 941         // try to assign the IP the client asked for
 942         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 943                         !find_assignment_by_addr(iface, raddr)) {
 944                 assign->addr = raddr;
 945                 syslog(LOG_INFO, "assigning the IP the client asked for: %u.%u.%u.%u",
 946                                 ((uint8_t *)&assign->addr)[0],
 947                                 ((uint8_t *)&assign->addr)[1],
 948                                 ((uint8_t *)&assign->addr)[2],
 949                                 ((uint8_t *)&assign->addr)[3]);
 950                 return true;
 951         }
 952
 953         // Seed RNG with checksum of hwaddress
 954         uint32_t seed = 0;
 955         for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) {
 956                 // Knuth's multiplicative method
 957                 uint8_t o = assign->hwaddr[i];
 958                 seed += (o*2654435761) % UINT32_MAX;
 959         }
 960
 961         srand(seed);
 962
 963         uint32_t try = (((uint32_t)rand()) % count) + start;
 964
 965         if (list_empty(&iface->dhcpv4_assignments)) {
 966                 assign->addr = htonl(try);
 967                 syslog(LOG_INFO, "assigning mapped IP (empty list): %u.%u.%u.%u",
 968                                 ((uint8_t *)&assign->addr)[0],
 969                                 ((uint8_t *)&assign->addr)[1],
 970                                 ((uint8_t *)&assign->addr)[2],
 971                                 ((uint8_t *)&assign->addr)[3]);
 972                 return true;
 973         }
 974
 975         for (uint32_t i = 0; i < count; ++i) {
 976                 if (!find_assignment_by_addr(iface, htonl(try))) {
 977                         /* test was successful: IP address is not assigned, assign it */
 978                         assign->addr = htonl(try);
 979                         syslog(LOG_DEBUG, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 980                                         ((uint8_t *)&assign->addr)[0],
 981                                         ((uint8_t *)&assign->addr)[1],
 982                                         ((uint8_t *)&assign->addr)[2],
 983                                         ((uint8_t *)&assign->addr)[3],
 984                                         i, count);
 985                         return true;
 986                 }
 987                 try = (((try - start) + 1) % count) + start;
 988         }
 989
 990         syslog(LOG_WARNING, "can't assign any IP address -> address space is full");
 991         return false;
 992 }
 993
 994
 995 static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 996                 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
 997                 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
 998                 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid)
 999 {
1000         struct dhcpv4_assignment *a = find_assignment_by_hwaddr(iface, mac);
1001         struct dhcpv4_assignment *lease = NULL;
1002         time_t now = odhcpd_time();
1003
1004         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1005                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1006                 dhcpv4_fr_stop(a);
1007         }
1008
1009         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1010                 bool assigned = !!a;
1011
1012                 if (!a) {
1013                         if (!iface->no_dynamic_dhcp) {
1014                                 /* Create new binding */
1015                                 a = calloc(1, sizeof(*a));
1016                                 if (!a) {
1017                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1018                                                         iface->ifname);
1019                                         return NULL;
1020                                 }
1021                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1022                                 /* Don't consider new assignment as infinite */
1023                                 a->valid_until = now;
1024
1025                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1026                                 if (assigned) {
1027                                         a->iface = iface;
1028                                         list_add(&a->head, &iface->dhcpv4_assignments);
1029                                 }
1030                         }
1031                 } else if ((a->addr & iface->dhcpv4_mask.s_addr) !=
1032                                 (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) {
1033                         list_del(&a->head);
1034
1035                         assigned = dhcpv4_assign(iface, a, reqaddr);
1036                         if (assigned)
1037                                 list_add(&a->head, &iface->dhcpv4_assignments);
1038                 }
1039
1040                 if (assigned) {
1041                         uint32_t my_leasetime;
1042
1043                         if (a->leasetime)
1044                                 my_leasetime = a->leasetime;
1045                         else
1046                                 my_leasetime = iface->dhcpv4_leasetime;
1047
1048                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1049                                 *leasetime = my_leasetime;
1050
1051                         if (msg == DHCPV4_MSG_DISCOVER) {
1052                                 a->flags &= ~OAF_BOUND;
1053
1054                                 *incl_fr_opt = accept_fr_nonce;
1055                                 if (!(a->flags & OAF_STATIC))
1056                                         a->valid_until = now;
1057                         } else {
1058                                 if (hostname_len > 0) {
1059                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1060                                         if (a->hostname) {
1061                                                 memcpy(a->hostname, hostname, hostname_len);
1062                                                 a->hostname[hostname_len] = 0;
1063                                         }
1064                                 }
1065
1066                                 if (!(a->flags & OAF_BOUND)) {
1067                                         a->accept_fr_nonce = accept_fr_nonce;
1068                                         *incl_fr_opt = accept_fr_nonce;
1069                                         odhcpd_urandom(a->key, sizeof(a->key));
1070                                         a->flags |= OAF_BOUND;
1071                                 } else
1072                                         *incl_fr_opt = false;
1073
1074                                 if (!(a->flags & OAF_STATIC))
1075                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1076                         }
1077                 } else if (!assigned && a) {
1078                         /* Cleanup failed assignment */
1079                         free_dhcpv4_assignment(a);
1080                         a = NULL;
1081                 }
1082
1083                 if (assigned && a)
1084                         lease = a;
1085         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1086                 a->flags &= ~OAF_BOUND;
1087
1088                 if (!(a->flags & OAF_STATIC))
1089                         a->valid_until = now - 1;
1090
1091         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1092                 a->flags &= ~OAF_BOUND;
1093
1094                 if (!(a->flags & OAF_STATIC)) {
1095                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1096                         a->valid_until = now + 3600; /* Block address for 1h */
1097                 }
1098         }
1099
1100         dhcpv6_write_statefile();
1101
1102         return lease;
1103 }