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 bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
  41 static void valid_until_cb(struct uloop_timeout *event);
  42 static void handle_addrlist_change(struct interface *iface);
  43 static void dhcpv4_fr_start(struct dhcp_assignment *a);
  44 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a);
  45 static void dhcpv4_fr_stop(struct dhcp_assignment *a);
  46 static void handle_dhcpv4(void *addr, void *data, size_t len,
  47                 struct interface *iface, void *dest_addr);
  48 static struct dhcp_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         } else if (iface->dhcpv4_assignments.next) {
 160                 while (!list_empty(&iface->dhcpv4_assignments))
 161                         dhcpv4_free_assignment(list_first_entry(&iface->dhcpv4_assignments,
 162                                                         struct dhcp_assignment, head));
 163         }
 164
 165 out:
 166         if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
 167                 close(iface->dhcpv4_event.uloop.fd);
 168                 iface->dhcpv4_event.uloop.fd = -1;
 169         }
 170
 171         return ret;
 172 }
 173
 174
 175 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 176 {
 177         struct interface *iface = info->iface;
 178
 179         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 180                 return;
 181
 182         switch (event) {
 183         case NETEV_IFINDEX_CHANGE:
 184                 dhcpv4_setup_interface(iface, true);
 185                 break;
 186         case NETEV_ADDRLIST_CHANGE:
 187                 handle_addrlist_change(iface);
 188                 break;
 189         default:
 190                 break;
 191         }
 192 }
 193
 194 static struct dhcp_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 195 {
 196         struct dhcp_assignment *a;
 197
 198         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 199                 if (!memcmp(a->hwaddr, hwaddr, 6))
 200                         return a;
 201
 202         return NULL;
 203 }
 204
 205 static int setup_dhcpv4_addresses(struct interface *iface)
 206 {
 207         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 208         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 209         iface->dhcpv4_local.s_addr = INADDR_ANY;
 210         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 211         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 212
 213         /* Sanity checks */
 214         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 215             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 216             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 217                 syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
 218                 return -1;
 219         }
 220
 221         if (!iface->addr4_len) {
 222                 syslog(LOG_WARNING, "No network(s) available on %s", iface->name);
 223                 return -1;
 224         }
 225
 226         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 227         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 228
 229         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 230                 struct in_addr *addr = &iface->addr4[i].addr.in;
 231                 struct in_addr mask;
 232
 233                 if (addr_is_fr_ip(iface, addr))
 234                         continue;
 235
 236                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 237                 if ((start & ntohl(~mask.s_addr)) == start &&
 238                             (end & ntohl(~mask.s_addr)) == end) {
 239                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 240                                                         (addr->s_addr & mask.s_addr);
 241                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 242                                                         (addr->s_addr & mask.s_addr);
 243                         iface->dhcpv4_local = *addr;
 244                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 245                         iface->dhcpv4_mask = mask;
 246                         return 0;
 247                 }
 248         }
 249
 250         /* Don't allocate IP range for subnets bigger than 28 */
 251         if (iface->addr4[0].prefix > 28) {
 252                 syslog(LOG_WARNING, "Auto allocation of DHCP range fails on %s", iface->name);
 253                 return -1;
 254         }
 255
 256         iface->dhcpv4_local = iface->addr4[0].addr.in;
 257         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 258         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 259         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 260
 261         /* Auto allocate ranges */
 262         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
 263                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 264                 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
 265         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
 266                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 267                 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
 268         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
 269                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 270                 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
 271         } else {
 272                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 273                 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
 274         }
 275
 276         return 0;
 277 }
 278
 279 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 280 {
 281         *ptr = ip;
 282         ip->ref_cnt++;
 283 }
 284
 285 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 286 {
 287         struct odhcpd_ref_ip *ip = *ptr;
 288
 289         if (--ip->ref_cnt == 0) {
 290                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 291
 292                 list_del(&ip->head);
 293                 free(ip);
 294         }
 295
 296         *ptr = NULL;
 297 }
 298
 299 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 300 {
 301         struct odhcpd_ref_ip *p;
 302
 303         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 304                 if (addr->s_addr == p->addr.addr.in.s_addr)
 305                         return true;
 306         }
 307
 308         return false;
 309 }
 310
 311 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 312                                 uint32_t mask)
 313 {
 314         struct dhcp_assignment *a = NULL;
 315         struct odhcpd_ref_ip *fr_ip = NULL;
 316
 317         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 318                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 319                     !a->fr_ip &&
 320                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 321                         if (!fr_ip) {
 322                                 fr_ip = calloc(1, sizeof(*fr_ip));
 323                                 if (!fr_ip)
 324                                         break;
 325
 326                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 327                                 fr_ip->addr = *addr;
 328                         }
 329                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 330                 }
 331         }
 332
 333         return fr_ip ? true : false;
 334 }
 335
 336 static void valid_until_cb(struct uloop_timeout *event)
 337 {
 338         struct interface *iface;
 339         time_t now = odhcpd_time();
 340
 341         avl_for_each_element(&interfaces, iface, avl) {
 342                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 343                         continue;
 344
 345                 struct dhcp_assignment *a, *n;
 346                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 347                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 348                                 dhcpv4_free_assignment(a);
 349                 }
 350         }
 351         uloop_timeout_set(event, 1000);
 352 }
 353
 354 static void handle_addrlist_change(struct interface *iface)
 355 {
 356         struct odhcpd_ipaddr ip;
 357         struct odhcpd_ref_ip *a;
 358         struct dhcp_assignment *c;
 359         uint32_t mask = iface->dhcpv4_mask.s_addr;
 360
 361         memset(&ip, 0, sizeof(ip));
 362         ip.addr.in = iface->dhcpv4_local;
 363         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 364         ip.broadcast = iface->dhcpv4_bcast;
 365
 366         setup_dhcpv4_addresses(iface);
 367
 368         if ((ip.addr.in.s_addr & mask) ==
 369             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 370                 return;
 371
 372         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 373                 return;
 374
 375         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 376                 return;
 377
 378         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 379
 380         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 381                 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
 382                 return;
 383         }
 384
 385         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 386                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 387                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 388                                 dhcpv4_fr_rand_delay(c);
 389                         else
 390                                 dhcpv4_fr_stop(c);
 391                 }
 392         }
 393 }
 394
 395 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 396 {
 397         switch (reqmsg) {
 398         case (DHCPV4_MSG_DISCOVER):
 399                 return "DHCPV4_MSG_DISCOVER";
 400         case (DHCPV4_MSG_OFFER):
 401                 return "DHCPV4_MSG_OFFER";
 402         case (DHCPV4_MSG_REQUEST):
 403                 return "DHCPV4_MSG_REQUEST";
 404         case (DHCPV4_MSG_DECLINE):
 405                 return "DHCPV4_MSG_DECLINE";
 406         case (DHCPV4_MSG_ACK):
 407                 return "DHCPV4_MSG_ACK";
 408         case (DHCPV4_MSG_NAK):
 409                 return "DHCPV4_MSG_NAK";
 410         case (DHCPV4_MSG_RELEASE):
 411                 return "DHCPV4_MSG_RELEASE";
 412         case (DHCPV4_MSG_INFORM):
 413                 return "DHCPV4_MSG_INFORM";
 414         case (DHCPV4_MSG_FORCERENEW):
 415                 return "DHCPV4_MSG_FORCERENEW";
 416         default:
 417                 return "UNKNOWN";
 418         }
 419 }
 420
 421 void dhcpv4_free_assignment(struct dhcp_assignment *a)
 422 {
 423         if (a->head.next)
 424                 list_del(&a->head);
 425
 426         if (a->lease_list.next)
 427                 list_del(&a->lease_list);
 428
 429         if (a->fr_ip)
 430                 dhcpv4_fr_stop(a);
 431
 432         free(a->hostname);
 433         free(a);
 434 }
 435
 436 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 437                 uint8_t type, uint8_t len, const void *data)
 438 {
 439         uint8_t *c = *cookie;
 440         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 441
 442         if (*cookie + 2 + len > end)
 443                 return;
 444
 445         *c++ = type;
 446         *c++ = len;
 447         memcpy(c, data, len);
 448
 449         *cookie = c + len;
 450 }
 451
 452 static void dhcpv4_fr_send(struct dhcp_assignment *a)
 453 {
 454         struct dhcpv4_message fr_msg = {
 455                 .op = DHCPV4_BOOTREPLY,
 456                 .htype = 1,
 457                 .hlen = 6,
 458                 .hops = 0,
 459                 .secs = 0,
 460                 .flags = 0,
 461                 .ciaddr = {INADDR_ANY},
 462                 .yiaddr = {INADDR_ANY},
 463                 .siaddr = {INADDR_ANY},
 464                 .giaddr = {INADDR_ANY},
 465                 .chaddr = {0},
 466                 .sname = {0},
 467                 .file = {0},
 468         };
 469         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 470                 .protocol = 3,
 471                 .algorithm = 1,
 472                 .rdm = 0,
 473                 .replay = {htonl(time(NULL)), htonl(++serial)},
 474                 .type = 2,
 475                 .key = {0},
 476         };
 477         struct interface *iface = a->iface;
 478
 479         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 480         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 481
 482         fr_msg.options[0] = 0x63;
 483         fr_msg.options[1] = 0x82;
 484         fr_msg.options[2] = 0x53;
 485         fr_msg.options[3] = 0x63;
 486
 487         uint8_t *cookie = &fr_msg.options[4];
 488         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 489
 490         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 491         if (a->accept_fr_nonce) {
 492                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 493                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 494                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 495
 496                 md5_ctx_t md5;
 497                 uint8_t secretbytes[64];
 498                 memset(secretbytes, 0, sizeof(secretbytes));
 499                 memcpy(secretbytes, a->key, sizeof(a->key));
 500
 501                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 502                         secretbytes[i] ^= 0x36;
 503
 504                 md5_begin(&md5);
 505                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 506                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 507                 md5_end(auth_o->key, &md5);
 508
 509                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 510                         secretbytes[i] ^= 0x36;
 511                         secretbytes[i] ^= 0x5c;
 512                 }
 513
 514                 md5_begin(&md5);
 515                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 516                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 517                 md5_end(auth_o->key, &md5);
 518         } else {
 519                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 520                                 &a->fr_ip->addr.addr.in.s_addr);
 521                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 522         }
 523
 524         struct sockaddr_in dest;
 525         memset(&dest, 0, sizeof(dest));
 526         dest.sin_family = AF_INET;
 527         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 528         dest.sin_addr.s_addr = a->addr;
 529
 530         if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
 531                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
 532                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
 533                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 534         else
 535                 syslog(LOG_WARNING, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
 536                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 537 }
 538
 539 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 540 {
 541         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 542
 543         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 544                 dhcpv4_fr_send(a);
 545                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 546                 a->fr_cnt++;
 547         } else
 548                 dhcpv4_fr_stop(a);
 549 }
 550
 551 static void dhcpv4_fr_start(struct dhcp_assignment *a)
 552 {
 553         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 554         a->fr_timer.cb = dhcpv4_fr_timer;
 555         a->fr_cnt++;
 556
 557         dhcpv4_fr_send(a);
 558 }
 559
 560 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
 561 {
 562         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 563         struct interface *iface = a->iface;
 564
 565         (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
 566 }
 567
 568 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a)
 569 {
 570 #define MIN_DELAY   500
 571 #define MAX_FUZZ    500
 572         int msecs;
 573
 574         odhcpd_urandom(&msecs, sizeof(msecs));
 575
 576         msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
 577
 578         uloop_timeout_set(&a->fr_timer, msecs);
 579         a->fr_timer.cb = dhcpv4_fr_delay_timer;
 580 }
 581
 582 static void dhcpv4_fr_stop(struct dhcp_assignment *a)
 583 {
 584         uloop_timeout_cancel(&a->fr_timer);
 585         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 586         a->fr_cnt = 0;
 587         a->fr_timer.cb = NULL;
 588 }
 589
 590 /* Handler for DHCPv4 messages */
 591 static void handle_dhcpv4(void *addr, void *data, size_t len,
 592                 struct interface *iface, _unused void *dest_addr)
 593 {
 594         struct dhcpv4_message *req = data;
 595
 596         if (!iface->dhcpv4)
 597                 return;
 598
 599         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 600                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 601                 return;
 602
 603         syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
 604
 605         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 606                 syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
 607                 return;
 608         }
 609
 610         int sock = iface->dhcpv4_event.uloop.fd;
 611
 612         struct dhcpv4_message reply = {
 613                 .op = DHCPV4_BOOTREPLY,
 614                 .htype = req->htype,
 615                 .hlen = req->hlen,
 616                 .hops = 0,
 617                 .xid = req->xid,
 618                 .secs = 0,
 619                 .flags = req->flags,
 620                 .ciaddr = {INADDR_ANY},
 621                 .giaddr = req->giaddr,
 622                 .siaddr = iface->dhcpv4_local,
 623         };
 624         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 625
 626         reply.options[0] = 0x63;
 627         reply.options[1] = 0x82;
 628         reply.options[2] = 0x53;
 629         reply.options[3] = 0x63;
 630
 631         uint8_t *cookie = &reply.options[4];
 632         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 633         uint8_t msg = DHCPV4_MSG_ACK;
 634
 635         uint32_t reqaddr = INADDR_ANY;
 636         uint32_t leasetime = 0;
 637         size_t hostname_len = 0;
 638         char hostname[256];
 639         bool accept_fr_nonce = false;
 640         bool incl_fr_opt = false;
 641
 642         uint8_t *start = &req->options[4];
 643         uint8_t *end = ((uint8_t*)data) + len;
 644         struct dhcpv4_option *opt;
 645         dhcpv4_for_each_option(start, end, opt) {
 646                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 647                         reqmsg = opt->data[0];
 648                 else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 649                         hostname_len = opt->len;
 650                         memcpy(hostname, opt->data, hostname_len);
 651                         hostname[hostname_len] = 0;
 652                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 653                         memcpy(&reqaddr, opt->data, 4);
 654                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 655                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 656                                 return;
 657                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 658                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 659                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 660                                 size_t elen = strlen(iface->filter_class);
 661                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 662                                         return; // Ignore from homenet
 663                         }
 664                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 665                         memcpy(&leasetime, opt->data, 4);
 666                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 667                         for (uint8_t i = 0; i < opt->len; i++) {
 668                                 if (opt->data[i] == 1) {
 669                                         accept_fr_nonce = true;
 670                                         break;
 671                                 }
 672                         }
 673
 674                 }
 675         }
 676
 677         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 678             reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 679             reqmsg != DHCPV4_MSG_RELEASE)
 680                 return;
 681
 682         struct dhcp_assignment *a = NULL;
 683         uint32_t serverid = iface->dhcpv4_local.s_addr;
 684         uint32_t fr_serverid = INADDR_ANY;
 685
 686         if (reqmsg != DHCPV4_MSG_INFORM)
 687                 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 688                                  &leasetime, hostname, hostname_len,
 689                                  accept_fr_nonce, &incl_fr_opt, &fr_serverid);
 690
 691         if (!a) {
 692                 if (reqmsg == DHCPV4_MSG_REQUEST)
 693                         msg = DHCPV4_MSG_NAK;
 694                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 695                         return;
 696         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 697                 msg = DHCPV4_MSG_OFFER;
 698         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 699                         ((reqaddr && reqaddr != a->addr) ||
 700                          (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
 701                 msg = DHCPV4_MSG_NAK;
 702                 /*
 703                  * DHCP client requested an IP which we can't offer to him. Probably the
 704                  * client changed the network or the network has been changed. The reply
 705                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 706                  *
 707                  * For modern devices we build an answer that includes a valid IP, like
 708                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 709                  * perform additional DHCP round trips.
 710                  *
 711                  */
 712
 713                 /*
 714                  *
 715                  * Buggy clients do serverid checking in nack messages; therefore set the
 716                  * serverid in nack messages triggered by a previous force renew equal to
 717                  * the server id in use at that time by the server
 718                  *
 719                  */
 720                 if (fr_serverid)
 721                         serverid = fr_serverid;
 722
 723                 if (req->ciaddr.s_addr &&
 724                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 725                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 726                         req->ciaddr.s_addr = INADDR_ANY;
 727         }
 728
 729         syslog(LOG_WARNING, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
 730                         odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
 731
 732 #ifdef WITH_UBUS
 733         if (reqmsg == DHCPV4_MSG_RELEASE)
 734                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 735                                         &req->ciaddr, hostname, iface->ifname);
 736 #endif
 737         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 738                 return;
 739
 740         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 741         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 742
 743         if (a) {
 744                 uint32_t val;
 745
 746                 reply.yiaddr.s_addr = a->addr;
 747
 748                 val = htonl(leasetime);
 749                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 750
 751                 if (leasetime != UINT32_MAX) {
 752                         val = htonl(500 * leasetime / 1000);
 753                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 754
 755                         val = htonl(875 * leasetime / 1000);
 756                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 757                 }
 758
 759                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 760                                 &iface->dhcpv4_mask.s_addr);
 761
 762                 if (a->hostname)
 763                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 764                                         strlen(a->hostname), a->hostname);
 765
 766                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 767                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 768
 769                 if (incl_fr_opt) {
 770                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 771                                 struct dhcpv4_auth_forcerenew auth = {
 772                                         .protocol = 3,
 773                                         .algorithm = 1,
 774                                         .rdm = 0,
 775                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 776                                         .type = 1,
 777                                         .key = {0},
 778                                 };
 779
 780                                 memcpy(auth.key, a->key, sizeof(auth.key));
 781                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 782                         } else {
 783                                 uint8_t one = 1;
 784                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 785                                         sizeof(one), &one);
 786                         }
 787                 }
 788         }
 789
 790         struct ifreq ifr;
 791
 792         memset(&ifr, 0, sizeof(ifr));
 793         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 794
 795         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 796                 uint16_t mtu = htons(ifr.ifr_mtu);
 797                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 798         }
 799
 800         if (iface->search && iface->search_len <= 255)
 801                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 802                                 iface->search_len, iface->search);
 803         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 804                 uint8_t search_buf[256];
 805                 int len = dn_comp(_res.dnsrch[0], search_buf,
 806                                                 sizeof(search_buf), NULL, NULL);
 807                 if (len > 0)
 808                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 809                                         len, search_buf);
 810         }
 811
 812         if (iface->dhcpv4_router_cnt == 0)
 813                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 814         else
 815                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 816                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 817
 818
 819         if (iface->dhcpv4_dns_cnt == 0)
 820                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 821         else
 822                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 823                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 824
 825
 826         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 827
 828         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 829         if (req->giaddr.s_addr) {
 830                 /*
 831                  * relay agent is configured, send reply to the agent
 832                  */
 833                 dest.sin_addr = req->giaddr;
 834                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 835         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 836                 /*
 837                  * client has existing configuration (ciaddr is set) AND this address is
 838                  * not the address it used for the dhcp message
 839                  */
 840                 dest.sin_addr = req->ciaddr;
 841                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 842         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 843                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 844                 /*
 845                  * client requests a broadcast reply OR we can't offer an IP
 846                  */
 847                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 848                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 849         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 850                 /*
 851                  * client has no previous configuration -> no IP, so we need to reply
 852                  * with a broadcast packet
 853                  */
 854                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 855                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 856         } else {
 857                 struct arpreq arp = {.arp_flags = ATF_COM};
 858
 859                 /*
 860                  * send reply to the newly (in this proccess) allocated IP
 861                  */
 862                 dest.sin_addr = reply.yiaddr;
 863                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 864
 865                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 866                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 867                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 868
 869                 if (ioctl(sock, SIOCSARP, &arp) < 0)
 870                         syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
 871         }
 872
 873         if (sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
 874                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 875                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 876                         dhcpv4_msg_to_string(msg),
 877                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 878                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 879                         inet_ntoa(dest.sin_addr));
 880         else
 881                 syslog(LOG_ERR, "Sent %s to %s - %s",
 882                         dhcpv4_msg_to_string(msg),
 883                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 884                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 885                         inet_ntoa(dest.sin_addr));
 886
 887
 888 #ifdef WITH_UBUS
 889         if (msg == DHCPV4_MSG_ACK)
 890                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 891                                         hostname, iface->ifname);
 892 #endif
 893 }
 894
 895 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
 896                           uint32_t raddr)
 897 {
 898         struct dhcp_assignment *c;
 899         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 900         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 901         uint32_t count = end - start + 1;
 902         uint32_t seed = 0;
 903
 904         /* Preconfigured IP address by static lease */
 905         if (a->addr) {
 906                 if (list_empty(&iface->dhcpv4_assignments)) {
 907                         list_add(&a->head, &iface->dhcpv4_assignments);
 908                         return true;
 909                 }
 910
 911                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 912                         if (ntohl(c->addr) > ntohl(a->addr)) {
 913                                 list_add_tail(&a->head, &c->head);
 914                                 return true;
 915                         } else if (ntohl(a->addr) == ntohl(c->addr))
 916                                 return false;
 917                 }
 918         }
 919
 920         /* try to assign the IP the client asked for */
 921         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 922             !config_find_lease_by_ipaddr(raddr)) {
 923                 if (list_empty(&iface->dhcpv4_assignments)) {
 924                         list_add(&a->head, &iface->dhcpv4_assignments);
 925                         goto raddr_out;
 926                 }
 927
 928                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 929                         if (ntohl(c->addr) > ntohl(raddr)) {
 930                                 list_add_tail(&a->head, &c->head);
 931 raddr_out:
 932                                 a->addr = raddr;
 933
 934                                 syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
 935                                        ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 936                                        ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 937
 938                                 return true;
 939                         } else if (ntohl(raddr) == ntohl(c->addr))
 940                                 break;
 941                 }
 942         }
 943
 944         /* Seed RNG with checksum of hwaddress */
 945         for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
 946                 /* Knuth's multiplicative method */
 947                 uint8_t o = a->hwaddr[i];
 948                 seed += (o*2654435761) % UINT32_MAX;
 949         }
 950
 951         srand(seed);
 952
 953         for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
 954              ++i, try = (((try - start) + 1) % count) + start) {
 955
 956                 if (config_find_lease_by_ipaddr(try))
 957                         continue;
 958
 959                 if (list_empty(&iface->dhcpv4_assignments)) {
 960                         list_add(&a->head, &iface->dhcpv4_assignments);
 961                         a->addr = htonl(try);
 962
 963                         syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
 964                                ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 965                                ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 966
 967                         return true;
 968                 }
 969
 970                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 971                         if (ntohl(c->addr) > try) {
 972                                 list_add_tail(&a->head, &c->head);
 973                                 a->addr = htonl(try);
 974
 975                                 syslog(LOG_DEBUG, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 976                                         ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 977                                         ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3],
 978                                         i, count);
 979
 980                                 return true;
 981                         } else if (try == ntohl(c->addr))
 982                                 break;
 983                 }
 984         }
 985
 986         syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
 987         return false;
 988 }
 989
 990
 991 static struct dhcp_assignment*
 992 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
 993              const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
 994              const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
 995              uint32_t *fr_serverid)
 996 {
 997         struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
 998         struct lease *l = config_find_lease_by_mac(mac);
 999         time_t now = odhcpd_time();
1000
1001         if (l && a && a->lease != l) {
1002                 dhcpv4_free_assignment(a);
1003                 a = NULL;
1004         }
1005
1006         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1007                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1008                 dhcpv4_fr_stop(a);
1009         }
1010
1011         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1012                 bool assigned = !!a;
1013
1014                 if (!a) {
1015                         if (!iface->no_dynamic_dhcp || l) {
1016                                 /* Create new binding */
1017                                 a = calloc(1, sizeof(*a));
1018                                 if (!a) {
1019                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1020                                                         iface->ifname);
1021                                         return NULL;
1022                                 }
1023                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1024                                 /* Set valid time to 0 for static lease indicating */
1025                                 /* infinite lifetime otherwise current time        */
1026                                 a->valid_until = l ? 0 : now;
1027                                 a->iface = iface;
1028                                 a->flags = OAF_DHCPV4;
1029                                 a->addr = l ? l->ipaddr : INADDR_ANY;
1030
1031                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1032
1033                                 if (l) {
1034                                         a->flags |= OAF_STATIC;
1035
1036                                         if (l->hostname)
1037                                                 a->hostname = strdup(l->hostname);
1038
1039                                         if (l->leasetime)
1040                                                 a->leasetime = l->leasetime;
1041
1042                                         list_add(&a->lease_list, &l->assignments);
1043                                         a->lease = l;
1044                                 }
1045                         }
1046                 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1047                             (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1048                             !(a->flags & OAF_STATIC)) {
1049                         list_del(&a->head);
1050                         a->addr = INADDR_ANY;
1051
1052                         assigned = dhcpv4_assign(iface, a, reqaddr);
1053                 }
1054
1055                 if (assigned) {
1056                         uint32_t my_leasetime;
1057
1058                         if (a->leasetime)
1059                                 my_leasetime = a->leasetime;
1060                         else
1061                                 my_leasetime = iface->dhcpv4_leasetime;
1062
1063                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1064                                 *leasetime = my_leasetime;
1065
1066                         if (msg == DHCPV4_MSG_DISCOVER) {
1067                                 a->flags &= ~OAF_BOUND;
1068
1069                                 *incl_fr_opt = accept_fr_nonce;
1070                                 if (!(a->flags & OAF_STATIC))
1071                                         a->valid_until = now;
1072                         } else {
1073                                 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1074                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1075                                         if (a->hostname) {
1076                                                 memcpy(a->hostname, hostname, hostname_len);
1077                                                 a->hostname[hostname_len] = 0;
1078
1079                                                 if (odhcpd_valid_hostname(a->hostname))
1080                                                         a->flags &= ~OAF_BROKEN_HOSTNAME;
1081                                                 else
1082                                                         a->flags |= OAF_BROKEN_HOSTNAME;
1083                                         }
1084                                 }
1085
1086                                 if (!(a->flags & OAF_BOUND)) {
1087                                         a->accept_fr_nonce = accept_fr_nonce;
1088                                         *incl_fr_opt = accept_fr_nonce;
1089                                         odhcpd_urandom(a->key, sizeof(a->key));
1090                                         a->flags |= OAF_BOUND;
1091                                 } else
1092                                         *incl_fr_opt = false;
1093
1094                                 if (!(a->flags & OAF_STATIC))
1095                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1096                         }
1097                 } else if (!assigned && a) {
1098                         /* Cleanup failed assignment */
1099                         dhcpv4_free_assignment(a);
1100                         a = NULL;
1101                 }
1102
1103         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1104                 a->flags &= ~OAF_BOUND;
1105
1106                 if (!(a->flags & OAF_STATIC))
1107                         a->valid_until = now - 1;
1108
1109         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1110                 a->flags &= ~OAF_BOUND;
1111
1112                 if (!(a->flags & OAF_STATIC)) {
1113                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1114                         a->valid_until = now + 3600; /* Block address for 1h */
1115                 }
1116         }
1117
1118         dhcpv6_ia_write_statefile();
1119
1120         return a;
1121 }