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