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 #define PACKET_SIZE(start, end) (((uint8_t *)end - (uint8_t *)start) < DHCPV4_MIN_PACKET_SIZE ? \
  39                                  DHCPV4_MIN_PACKET_SIZE : (uint8_t *)end - (uint8_t *)start)
  40
  41 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
  42 static int setup_dhcpv4_addresses(struct interface *iface);
  43 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
  44 static void valid_until_cb(struct uloop_timeout *event);
  45 static void handle_addrlist_change(struct interface *iface);
  46 static void dhcpv4_fr_start(struct dhcp_assignment *a);
  47 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a);
  48 static void dhcpv4_fr_stop(struct dhcp_assignment *a);
  49 static void handle_dhcpv4(void *addr, void *data, size_t len,
  50                 struct interface *iface, void *dest_addr);
  51 static struct dhcp_assignment* dhcpv4_lease(struct interface *iface,
  52                 enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
  53                 uint32_t *leasetime, const char *hostname, const size_t hostname_len,
  54                 const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid,
  55                 const char *reqopts, const size_t reqopts_len);
  56
  57 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
  58 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
  59 static uint32_t serial = 0;
  60
  61 struct odhcpd_ref_ip {
  62         struct list_head head;
  63         int ref_cnt;
  64         struct odhcpd_ipaddr addr;
  65 };
  66
  67 /* Create socket and register events */
  68 int dhcpv4_init(void)
  69 {
  70         uloop_timeout_set(&valid_until_timeout, 1000);
  71         netlink_add_netevent_handler(&dhcpv4_netevent_handler);
  72
  73         return 0;
  74 }
  75
  76 int dhcpv4_setup_interface(struct interface *iface, bool enable)
  77 {
  78         int ret = 0;
  79
  80         if (iface->dhcpv4_event.uloop.fd >= 0) {
  81                 uloop_fd_delete(&iface->dhcpv4_event.uloop);
  82                 close(iface->dhcpv4_event.uloop.fd);
  83                 iface->dhcpv4_event.uloop.fd = -1;
  84         }
  85
  86         if (iface->dhcpv4 && enable) {
  87                 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
  88                                         {INADDR_ANY}, {0}};
  89                 int val = 1;
  90
  91                 if (!iface->dhcpv4_assignments.next)
  92                         INIT_LIST_HEAD(&iface->dhcpv4_assignments);
  93
  94                 if (!iface->dhcpv4_fr_ips.next)
  95                         INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
  96
  97                 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  98                 if (iface->dhcpv4_event.uloop.fd < 0) {
  99                         syslog(LOG_ERR, "socket(AF_INET): %m");
 100                         ret = -1;
 101                         goto out;
 102                 }
 103
 104                 /* Basic IPv4 configuration */
 105                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
 106                                         &val, sizeof(val)) < 0) {
 107                         syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
 108                         ret = -1;
 109                         goto out;
 110                 }
 111
 112                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
 113                                         &val, sizeof(val)) < 0) {
 114                         syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
 115                         ret = -1;
 116                         goto out;
 117                 }
 118
 119                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
 120                                         &val, sizeof(val)) < 0) {
 121                         syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
 122                         ret = -1;
 123                         goto out;
 124                 }
 125
 126                 val = IPTOS_PREC_INTERNETCONTROL;
 127                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
 128                                         &val, sizeof(val)) < 0) {
 129                         syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
 130                         ret = -1;
 131                         goto out;
 132                 }
 133
 134                 val = IP_PMTUDISC_DONT;
 135                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
 136                                         &val, sizeof(val)) < 0) {
 137                         syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
 138                         ret = -1;
 139                         goto out;
 140                 }
 141
 142                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 143                                         iface->ifname, strlen(iface->ifname)) < 0) {
 144                         syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 145                         ret = -1;
 146                         goto out;
 147                 }
 148
 149                 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
 150                                         sizeof(bind_addr)) < 0) {
 151                         syslog(LOG_ERR, "bind(): %m");
 152                         ret = -1;
 153                         goto out;
 154                 }
 155
 156                 if (setup_dhcpv4_addresses(iface) < 0) {
 157                         ret = -1;
 158                         goto out;
 159                 }
 160
 161                 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
 162                 odhcpd_register(&iface->dhcpv4_event);
 163         } else if (iface->dhcpv4_assignments.next) {
 164                 while (!list_empty(&iface->dhcpv4_assignments))
 165                         free_assignment(list_first_entry(&iface->dhcpv4_assignments,
 166                                                         struct dhcp_assignment, head));
 167         }
 168
 169 out:
 170         if (ret < 0 && iface->dhcpv4_event.uloop.fd >= 0) {
 171                 close(iface->dhcpv4_event.uloop.fd);
 172                 iface->dhcpv4_event.uloop.fd = -1;
 173         }
 174
 175         return ret;
 176 }
 177
 178
 179 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 180 {
 181         struct interface *iface = info->iface;
 182
 183         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 184                 return;
 185
 186         switch (event) {
 187         case NETEV_IFINDEX_CHANGE:
 188                 dhcpv4_setup_interface(iface, true);
 189                 break;
 190         case NETEV_ADDRLIST_CHANGE:
 191                 handle_addrlist_change(iface);
 192                 break;
 193         default:
 194                 break;
 195         }
 196 }
 197
 198 static struct dhcp_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 199 {
 200         struct dhcp_assignment *a;
 201
 202         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 203                 if (!memcmp(a->hwaddr, hwaddr, 6))
 204                         return a;
 205
 206         return NULL;
 207 }
 208
 209 static int setup_dhcpv4_addresses(struct interface *iface)
 210 {
 211         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 212         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 213         iface->dhcpv4_local.s_addr = INADDR_ANY;
 214         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 215         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 216
 217         /* Sanity checks */
 218         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 219             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 220             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 221                 syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
 222                 return -1;
 223         }
 224
 225         if (!iface->addr4_len) {
 226                 syslog(LOG_ERR, "No network(s) available on %s", iface->name);
 227                 return -1;
 228         }
 229
 230         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 231         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 232
 233         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 234                 struct in_addr *addr = &iface->addr4[i].addr.in;
 235                 struct in_addr mask;
 236
 237                 if (addr_is_fr_ip(iface, addr))
 238                         continue;
 239
 240                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 241                 if ((start & ntohl(~mask.s_addr)) == start &&
 242                             (end & ntohl(~mask.s_addr)) == end) {
 243                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 244                                                         (addr->s_addr & mask.s_addr);
 245                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 246                                                         (addr->s_addr & mask.s_addr);
 247                         iface->dhcpv4_local = *addr;
 248                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 249                         iface->dhcpv4_mask = mask;
 250                         return 0;
 251                 }
 252         }
 253
 254         /* Don't allocate IP range for subnets bigger than 28 */
 255         if (iface->addr4[0].prefix > 28) {
 256                 syslog(LOG_ERR, "Auto allocation of DHCP range fails on %s", iface->name);
 257                 return -1;
 258         }
 259
 260         iface->dhcpv4_local = iface->addr4[0].addr.in;
 261         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 262         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 263         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 264
 265         /* Auto allocate ranges */
 266         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
 267                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 268                 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
 269         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
 270                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 271                 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
 272         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
 273                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 274                 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
 275         } else {
 276                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 277                 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
 278         }
 279
 280         return 0;
 281 }
 282
 283 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 284 {
 285         *ptr = ip;
 286         ip->ref_cnt++;
 287 }
 288
 289 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 290 {
 291         struct odhcpd_ref_ip *ip = *ptr;
 292
 293         if (--ip->ref_cnt == 0) {
 294                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 295
 296                 list_del(&ip->head);
 297                 free(ip);
 298         }
 299
 300         *ptr = NULL;
 301 }
 302
 303 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 304 {
 305         struct odhcpd_ref_ip *p;
 306
 307         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 308                 if (addr->s_addr == p->addr.addr.in.s_addr)
 309                         return true;
 310         }
 311
 312         return false;
 313 }
 314
 315 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 316                                 uint32_t mask)
 317 {
 318         struct dhcp_assignment *a = NULL;
 319         struct odhcpd_ref_ip *fr_ip = NULL;
 320
 321         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 322                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 323                     !a->fr_ip &&
 324                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 325                         if (!fr_ip) {
 326                                 fr_ip = calloc(1, sizeof(*fr_ip));
 327                                 if (!fr_ip)
 328                                         break;
 329
 330                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 331                                 fr_ip->addr = *addr;
 332                         }
 333                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 334                 }
 335         }
 336
 337         return fr_ip ? true : false;
 338 }
 339
 340 static void valid_until_cb(struct uloop_timeout *event)
 341 {
 342         struct interface *iface;
 343         time_t now = odhcpd_time();
 344
 345         avl_for_each_element(&interfaces, iface, avl) {
 346                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 347                         continue;
 348
 349                 struct dhcp_assignment *a, *n;
 350                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 351                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 352                                 free_assignment(a);
 353                 }
 354         }
 355         uloop_timeout_set(event, 1000);
 356 }
 357
 358 static void handle_addrlist_change(struct interface *iface)
 359 {
 360         struct odhcpd_ipaddr ip;
 361         struct odhcpd_ref_ip *a;
 362         struct dhcp_assignment *c;
 363         uint32_t mask = iface->dhcpv4_mask.s_addr;
 364
 365         memset(&ip, 0, sizeof(ip));
 366         ip.addr.in = iface->dhcpv4_local;
 367         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 368         ip.broadcast = iface->dhcpv4_bcast;
 369
 370         setup_dhcpv4_addresses(iface);
 371
 372         if ((ip.addr.in.s_addr & mask) ==
 373             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 374                 return;
 375
 376         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 377                 return;
 378
 379         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 380                 return;
 381
 382         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 383
 384         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 385                 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
 386                 return;
 387         }
 388
 389         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 390                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 391                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 392                                 dhcpv4_fr_rand_delay(c);
 393                         else
 394                                 dhcpv4_fr_stop(c);
 395                 }
 396         }
 397 }
 398
 399 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 400 {
 401         switch (reqmsg) {
 402         case (DHCPV4_MSG_DISCOVER):
 403                 return "DHCPV4_MSG_DISCOVER";
 404         case (DHCPV4_MSG_OFFER):
 405                 return "DHCPV4_MSG_OFFER";
 406         case (DHCPV4_MSG_REQUEST):
 407                 return "DHCPV4_MSG_REQUEST";
 408         case (DHCPV4_MSG_DECLINE):
 409                 return "DHCPV4_MSG_DECLINE";
 410         case (DHCPV4_MSG_ACK):
 411                 return "DHCPV4_MSG_ACK";
 412         case (DHCPV4_MSG_NAK):
 413                 return "DHCPV4_MSG_NAK";
 414         case (DHCPV4_MSG_RELEASE):
 415                 return "DHCPV4_MSG_RELEASE";
 416         case (DHCPV4_MSG_INFORM):
 417                 return "DHCPV4_MSG_INFORM";
 418         case (DHCPV4_MSG_FORCERENEW):
 419                 return "DHCPV4_MSG_FORCERENEW";
 420         default:
 421                 return "UNKNOWN";
 422         }
 423 }
 424
 425 static void dhcpv4_free_assignment(struct dhcp_assignment *a)
 426 {
 427         if (a->fr_ip)
 428                 dhcpv4_fr_stop(a);
 429 }
 430
 431 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 432                 uint8_t type, uint8_t len, const void *data)
 433 {
 434         uint8_t *c = *cookie;
 435         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 436         bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END;
 437         int total_len = tag_only ? 1 : 2 + len;
 438
 439         if (*cookie + total_len > end)
 440                 return;
 441
 442         *cookie += total_len;
 443         *c++ = type;
 444
 445         if (tag_only)
 446                 return;
 447
 448         *c++ = len;
 449         memcpy(c, data, 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, PACKET_SIZE(&fr_msg, cookie),
 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_NOTICE, "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_ERR, "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         size_t reqopts_len = 0;
 639         char hostname[256];
 640         char reqopts[256];
 641         bool accept_fr_nonce = false;
 642         bool incl_fr_opt = false;
 643
 644         uint8_t *start = &req->options[4];
 645         uint8_t *end = ((uint8_t*)data) + len;
 646         struct dhcpv4_option *opt;
 647         dhcpv4_for_each_option(start, end, opt) {
 648                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 649                         reqmsg = opt->data[0];
 650                 else if (opt->type == DHCPV4_OPT_REQOPTS && opt->len > 0) {
 651                         reqopts_len = opt->len;
 652                         memcpy(reqopts, opt->data, reqopts_len);
 653                         reqopts[reqopts_len] = 0;
 654                 } else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 655                         hostname_len = opt->len;
 656                         memcpy(hostname, opt->data, hostname_len);
 657                         hostname[hostname_len] = 0;
 658                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 659                         memcpy(&reqaddr, opt->data, 4);
 660                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 661                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 662                                 return;
 663                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 664                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 665                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 666                                 size_t elen = strlen(iface->filter_class);
 667                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 668                                         return; // Ignore from homenet
 669                         }
 670                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 671                         memcpy(&leasetime, opt->data, 4);
 672                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 673                         for (uint8_t i = 0; i < opt->len; i++) {
 674                                 if (opt->data[i] == 1) {
 675                                         accept_fr_nonce = true;
 676                                         break;
 677                                 }
 678                         }
 679
 680                 }
 681         }
 682
 683         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 684             reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 685             reqmsg != DHCPV4_MSG_RELEASE)
 686                 return;
 687
 688         struct dhcp_assignment *a = NULL;
 689         uint32_t serverid = iface->dhcpv4_local.s_addr;
 690         uint32_t fr_serverid = INADDR_ANY;
 691
 692         if (reqmsg != DHCPV4_MSG_INFORM)
 693                 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 694                                  &leasetime, hostname, hostname_len,
 695                                  accept_fr_nonce, &incl_fr_opt, &fr_serverid,
 696                                  reqopts, reqopts_len);
 697
 698         if (!a) {
 699                 if (reqmsg == DHCPV4_MSG_REQUEST)
 700                         msg = DHCPV4_MSG_NAK;
 701                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 702                         return;
 703         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 704                 msg = DHCPV4_MSG_OFFER;
 705         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 706                         ((reqaddr && reqaddr != a->addr) ||
 707                          (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
 708                 msg = DHCPV4_MSG_NAK;
 709                 /*
 710                  * DHCP client requested an IP which we can't offer to him. Probably the
 711                  * client changed the network or the network has been changed. The reply
 712                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 713                  *
 714                  * For modern devices we build an answer that includes a valid IP, like
 715                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 716                  * perform additional DHCP round trips.
 717                  *
 718                  */
 719
 720                 /*
 721                  *
 722                  * Buggy clients do serverid checking in nack messages; therefore set the
 723                  * serverid in nack messages triggered by a previous force renew equal to
 724                  * the server id in use at that time by the server
 725                  *
 726                  */
 727                 if (fr_serverid)
 728                         serverid = fr_serverid;
 729
 730                 if (req->ciaddr.s_addr &&
 731                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 732                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 733                         req->ciaddr.s_addr = INADDR_ANY;
 734         }
 735
 736         syslog(LOG_NOTICE, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
 737                         odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
 738
 739 #ifdef WITH_UBUS
 740         if (reqmsg == DHCPV4_MSG_RELEASE)
 741                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 742                                         &req->ciaddr, hostname, iface->ifname);
 743 #endif
 744         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 745                 return;
 746
 747         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 748         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 749
 750         if (a) {
 751                 uint32_t val;
 752
 753                 reply.yiaddr.s_addr = a->addr;
 754
 755                 val = htonl(leasetime);
 756                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 757
 758                 if (leasetime != UINT32_MAX) {
 759                         val = htonl(500 * leasetime / 1000);
 760                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 761
 762                         val = htonl(875 * leasetime / 1000);
 763                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 764                 }
 765
 766                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 767                                 &iface->dhcpv4_mask.s_addr);
 768
 769                 if (a->hostname)
 770                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 771                                         strlen(a->hostname), a->hostname);
 772
 773                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 774                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 775
 776                 if (incl_fr_opt) {
 777                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 778                                 struct dhcpv4_auth_forcerenew auth = {
 779                                         .protocol = 3,
 780                                         .algorithm = 1,
 781                                         .rdm = 0,
 782                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 783                                         .type = 1,
 784                                         .key = {0},
 785                                 };
 786
 787                                 memcpy(auth.key, a->key, sizeof(auth.key));
 788                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 789                         } else {
 790                                 uint8_t one = 1;
 791                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 792                                         sizeof(one), &one);
 793                         }
 794                 }
 795         }
 796
 797         struct ifreq ifr;
 798
 799         memset(&ifr, 0, sizeof(ifr));
 800         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 801
 802         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 803                 uint16_t mtu = htons(ifr.ifr_mtu);
 804                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 805         }
 806
 807         if (iface->search && iface->search_len <= 255)
 808                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 809                                 iface->search_len, iface->search);
 810         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 811                 uint8_t search_buf[256];
 812                 int len = dn_comp(_res.dnsrch[0], search_buf,
 813                                                 sizeof(search_buf), NULL, NULL);
 814                 if (len > 0)
 815                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 816                                         len, search_buf);
 817         }
 818
 819         if (iface->dhcpv4_router_cnt == 0)
 820                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 821         else
 822                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 823                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 824
 825
 826         if (iface->dhcpv4_dns_cnt == 0)
 827                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 828         else
 829                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 830                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 831
 832
 833         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 834
 835         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 836         if (req->giaddr.s_addr) {
 837                 /*
 838                  * relay agent is configured, send reply to the agent
 839                  */
 840                 dest.sin_addr = req->giaddr;
 841                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 842         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 843                 /*
 844                  * client has existing configuration (ciaddr is set) AND this address is
 845                  * not the address it used for the dhcp message
 846                  */
 847                 dest.sin_addr = req->ciaddr;
 848                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 849         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 850                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 851                 /*
 852                  * client requests a broadcast reply OR we can't offer an IP
 853                  */
 854                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 855                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 856         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 857                 /*
 858                  * client has no previous configuration -> no IP, so we need to reply
 859                  * with a broadcast packet
 860                  */
 861                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 862                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 863         } else {
 864                 struct arpreq arp = {.arp_flags = ATF_COM};
 865
 866                 /*
 867                  * send reply to the newly (in this proccess) allocated IP
 868                  */
 869                 dest.sin_addr = reply.yiaddr;
 870                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 871
 872                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 873                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 874                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 875
 876                 if (ioctl(sock, SIOCSARP, &arp) < 0)
 877                         syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
 878         }
 879
 880         if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT,
 881                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 882                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 883                         dhcpv4_msg_to_string(msg),
 884                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 885                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 886                         inet_ntoa(dest.sin_addr));
 887         else
 888                 syslog(LOG_NOTICE, "Sent %s to %s - %s",
 889                         dhcpv4_msg_to_string(msg),
 890                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 891                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 892                         inet_ntoa(dest.sin_addr));
 893
 894
 895 #ifdef WITH_UBUS
 896         if (msg == DHCPV4_MSG_ACK)
 897                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 898                                         hostname, iface->ifname);
 899 #endif
 900 }
 901
 902 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
 903                           uint32_t raddr)
 904 {
 905         struct dhcp_assignment *c;
 906         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 907         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 908         uint32_t count = end - start + 1;
 909         uint32_t seed = 0;
 910
 911         /* Preconfigured IP address by static lease */
 912         if (a->addr) {
 913                 if (list_empty(&iface->dhcpv4_assignments)) {
 914                         list_add(&a->head, &iface->dhcpv4_assignments);
 915                         return true;
 916                 }
 917
 918                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 919                         if (ntohl(c->addr) > ntohl(a->addr)) {
 920                                 list_add_tail(&a->head, &c->head);
 921                                 return true;
 922                         } else if (ntohl(a->addr) == ntohl(c->addr))
 923                                 return false;
 924                 }
 925         }
 926
 927         /* try to assign the IP the client asked for */
 928         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 929             !config_find_lease_by_ipaddr(raddr)) {
 930                 if (list_empty(&iface->dhcpv4_assignments)) {
 931                         list_add(&a->head, &iface->dhcpv4_assignments);
 932                         goto raddr_out;
 933                 }
 934
 935                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 936                         if (ntohl(raddr) == ntohl(c->addr))
 937                                 break;
 938
 939                         if (ntohl(c->addr) > ntohl(raddr) || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 940                                 list_add_tail(&a->head,
 941                                               ntohl(c->addr) > ntohl(raddr) ? &c->head : &iface->dhcpv4_assignments);
 942 raddr_out:
 943                                 a->addr = raddr;
 944
 945                                 syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
 946                                        ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 947                                        ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 948
 949                                 return true;
 950                         }
 951                 }
 952         }
 953
 954         /* Seed RNG with checksum of hwaddress */
 955         for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
 956                 /* Knuth's multiplicative method */
 957                 uint8_t o = a->hwaddr[i];
 958                 seed += (o*2654435761) % UINT32_MAX;
 959         }
 960
 961         srand(seed);
 962
 963         for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
 964              ++i, try = (((try - start) + 1) % count) + start) {
 965
 966                 if (config_find_lease_by_ipaddr(htonl(try)))
 967                         continue;
 968
 969                 if (list_empty(&iface->dhcpv4_assignments)) {
 970                         list_add(&a->head, &iface->dhcpv4_assignments);
 971                         a->addr = htonl(try);
 972
 973                         syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
 974                                ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 975                                ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 976
 977                         return true;
 978                 }
 979
 980                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 981                         if (try == ntohl(c->addr))
 982                                 break;
 983
 984                         if (ntohl(c->addr) > try || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 985                                 list_add_tail(&a->head,
 986                                               ntohl(c->addr) > try ? &c->head : &iface->dhcpv4_assignments);
 987                                 a->addr = htonl(try);
 988
 989                                 syslog(LOG_INFO, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 990                                         ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 991                                         ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3],
 992                                         i, count);
 993
 994                                 return true;
 995                         }
 996                 }
 997         }
 998
 999         syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
1000         return false;
1001 }
1002
1003
1004 static struct dhcp_assignment*
1005 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
1006              const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
1007              const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
1008              uint32_t *fr_serverid, const char* reqopts, const size_t reqopts_len)
1009 {
1010         struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
1011         struct lease *l = config_find_lease_by_mac(mac);
1012         time_t now = odhcpd_time();
1013
1014         if (l && a && a->lease != l) {
1015                 free_assignment(a);
1016                 a = NULL;
1017         }
1018
1019         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1020                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1021                 dhcpv4_fr_stop(a);
1022         }
1023
1024         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1025                 bool assigned = !!a;
1026
1027                 if (!a) {
1028                         if (!iface->no_dynamic_dhcp || l) {
1029                                 /* Create new binding */
1030                                 a = calloc(1, sizeof(*a));
1031                                 if (!a) {
1032                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1033                                                         iface->ifname);
1034                                         return NULL;
1035                                 }
1036                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1037                                 /* Set valid time to 0 for static lease indicating */
1038                                 /* infinite lifetime otherwise current time        */
1039                                 a->valid_until = l ? 0 : now;
1040                                 a->dhcp_free_cb = dhcpv4_free_assignment;
1041                                 a->iface = iface;
1042                                 a->flags = OAF_DHCPV4;
1043                                 a->addr = l ? l->ipaddr : INADDR_ANY;
1044
1045                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1046
1047                                 if (l) {
1048                                         a->flags |= OAF_STATIC;
1049
1050                                         if (l->hostname)
1051                                                 a->hostname = strdup(l->hostname);
1052
1053                                         if (l->leasetime)
1054                                                 a->leasetime = l->leasetime;
1055
1056                                         list_add(&a->lease_list, &l->assignments);
1057                                         a->lease = l;
1058                                 }
1059                         }
1060                 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1061                             (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1062                             !(a->flags & OAF_STATIC)) {
1063                         list_del(&a->head);
1064                         a->addr = INADDR_ANY;
1065
1066                         assigned = dhcpv4_assign(iface, a, reqaddr);
1067                 }
1068
1069                 if (assigned) {
1070                         uint32_t my_leasetime;
1071
1072                         if (a->leasetime)
1073                                 my_leasetime = a->leasetime;
1074                         else
1075                                 my_leasetime = iface->dhcpv4_leasetime;
1076
1077                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1078                                 *leasetime = my_leasetime;
1079
1080                         if (msg == DHCPV4_MSG_DISCOVER) {
1081                                 a->flags &= ~OAF_BOUND;
1082
1083                                 *incl_fr_opt = accept_fr_nonce;
1084                                 if (!(a->flags & OAF_STATIC))
1085                                         a->valid_until = now;
1086                         } else {
1087                                 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1088                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1089                                         if (a->hostname) {
1090                                                 memcpy(a->hostname, hostname, hostname_len);
1091                                                 a->hostname[hostname_len] = 0;
1092
1093                                                 if (odhcpd_valid_hostname(a->hostname))
1094                                                         a->flags &= ~OAF_BROKEN_HOSTNAME;
1095                                                 else
1096                                                         a->flags |= OAF_BROKEN_HOSTNAME;
1097                                         }
1098                                 }
1099
1100                                 if (reqopts_len > 0) {
1101                                         a->reqopts = realloc(a->reqopts, reqopts_len + 1);
1102                                         if (a->reqopts) {
1103                                                 memcpy(a->reqopts, reqopts, reqopts_len);
1104                                                 a->reqopts[reqopts_len] = 0;
1105                                         }
1106                                 }
1107
1108                                 if (!(a->flags & OAF_BOUND)) {
1109                                         a->accept_fr_nonce = accept_fr_nonce;
1110                                         *incl_fr_opt = accept_fr_nonce;
1111                                         odhcpd_urandom(a->key, sizeof(a->key));
1112                                         a->flags |= OAF_BOUND;
1113                                 } else
1114                                         *incl_fr_opt = false;
1115
1116                                 if (!(a->flags & OAF_STATIC))
1117                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1118                         }
1119                 } else if (!assigned && a) {
1120                         /* Cleanup failed assignment */
1121                         free_assignment(a);
1122                         a = NULL;
1123                 }
1124
1125         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1126                 a->flags &= ~OAF_BOUND;
1127
1128                 if (!(a->flags & OAF_STATIC))
1129                         a->valid_until = now - 1;
1130
1131         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1132                 a->flags &= ~OAF_BOUND;
1133
1134                 if (!(a->flags & OAF_STATIC)) {
1135                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1136                         a->valid_until = now + 3600; /* Block address for 1h */
1137                 }
1138         }
1139
1140         dhcpv6_ia_write_statefile();
1141
1142         return a;
1143 }