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
  56 static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
  57 static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
  58 static uint32_t serial = 0;
  59
  60 struct odhcpd_ref_ip {
  61         struct list_head head;
  62         int ref_cnt;
  63         struct odhcpd_ipaddr addr;
  64 };
  65
  66 /* Create socket and register events */
  67 int dhcpv4_init(void)
  68 {
  69         uloop_timeout_set(&valid_until_timeout, 1000);
  70         netlink_add_netevent_handler(&dhcpv4_netevent_handler);
  71
  72         return 0;
  73 }
  74
  75 int dhcpv4_setup_interface(struct interface *iface, bool enable)
  76 {
  77         int ret = 0;
  78
  79         if (iface->dhcpv4_event.uloop.fd >= 0) {
  80                 uloop_fd_delete(&iface->dhcpv4_event.uloop);
  81                 close(iface->dhcpv4_event.uloop.fd);
  82                 iface->dhcpv4_event.uloop.fd = -1;
  83         }
  84
  85         if (iface->dhcpv4 && enable) {
  86                 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
  87                                         {INADDR_ANY}, {0}};
  88                 int val = 1;
  89
  90                 if (!iface->dhcpv4_assignments.next)
  91                         INIT_LIST_HEAD(&iface->dhcpv4_assignments);
  92
  93                 if (!iface->dhcpv4_fr_ips.next)
  94                         INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
  95
  96                 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  97                 if (iface->dhcpv4_event.uloop.fd < 0) {
  98                         syslog(LOG_ERR, "socket(AF_INET): %m");
  99                         ret = -1;
 100                         goto out;
 101                 }
 102
 103                 /* Basic IPv4 configuration */
 104                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
 105                                         &val, sizeof(val)) < 0) {
 106                         syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
 107                         ret = -1;
 108                         goto out;
 109                 }
 110
 111                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
 112                                         &val, sizeof(val)) < 0) {
 113                         syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
 114                         ret = -1;
 115                         goto out;
 116                 }
 117
 118                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
 119                                         &val, sizeof(val)) < 0) {
 120                         syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
 121                         ret = -1;
 122                         goto out;
 123                 }
 124
 125                 val = IPTOS_PREC_INTERNETCONTROL;
 126                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
 127                                         &val, sizeof(val)) < 0) {
 128                         syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
 129                         ret = -1;
 130                         goto out;
 131                 }
 132
 133                 val = IP_PMTUDISC_DONT;
 134                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
 135                                         &val, sizeof(val)) < 0) {
 136                         syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
 137                         ret = -1;
 138                         goto out;
 139                 }
 140
 141                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 142                                         iface->ifname, strlen(iface->ifname)) < 0) {
 143                         syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 144                         ret = -1;
 145                         goto out;
 146                 }
 147
 148                 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
 149                                         sizeof(bind_addr)) < 0) {
 150                         syslog(LOG_ERR, "bind(): %m");
 151                         ret = -1;
 152                         goto out;
 153                 }
 154
 155                 if (setup_dhcpv4_addresses(iface) < 0) {
 156                         ret = -1;
 157                         goto out;
 158                 }
 159
 160                 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
 161                 odhcpd_register(&iface->dhcpv4_event);
 162         } else if (iface->dhcpv4_assignments.next) {
 163                 while (!list_empty(&iface->dhcpv4_assignments))
 164                         free_assignment(list_first_entry(&iface->dhcpv4_assignments,
 165                                                         struct dhcp_assignment, head));
 166         }
 167
 168 out:
 169         if (ret < 0 && iface->dhcpv4_event.uloop.fd >= 0) {
 170                 close(iface->dhcpv4_event.uloop.fd);
 171                 iface->dhcpv4_event.uloop.fd = -1;
 172         }
 173
 174         return ret;
 175 }
 176
 177
 178 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 179 {
 180         struct interface *iface = info->iface;
 181
 182         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 183                 return;
 184
 185         switch (event) {
 186         case NETEV_IFINDEX_CHANGE:
 187                 dhcpv4_setup_interface(iface, true);
 188                 break;
 189         case NETEV_ADDRLIST_CHANGE:
 190                 handle_addrlist_change(iface);
 191                 break;
 192         default:
 193                 break;
 194         }
 195 }
 196
 197 static struct dhcp_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 198 {
 199         struct dhcp_assignment *a;
 200
 201         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 202                 if (!memcmp(a->hwaddr, hwaddr, 6))
 203                         return a;
 204
 205         return NULL;
 206 }
 207
 208 static int setup_dhcpv4_addresses(struct interface *iface)
 209 {
 210         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 211         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 212         iface->dhcpv4_local.s_addr = INADDR_ANY;
 213         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 214         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 215
 216         /* Sanity checks */
 217         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 218             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 219             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 220                 syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
 221                 return -1;
 222         }
 223
 224         if (!iface->addr4_len) {
 225                 syslog(LOG_ERR, "No network(s) available on %s", iface->name);
 226                 return -1;
 227         }
 228
 229         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 230         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 231
 232         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 233                 struct in_addr *addr = &iface->addr4[i].addr.in;
 234                 struct in_addr mask;
 235
 236                 if (addr_is_fr_ip(iface, addr))
 237                         continue;
 238
 239                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 240                 if ((start & ntohl(~mask.s_addr)) == start &&
 241                             (end & ntohl(~mask.s_addr)) == end) {
 242                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 243                                                         (addr->s_addr & mask.s_addr);
 244                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 245                                                         (addr->s_addr & mask.s_addr);
 246                         iface->dhcpv4_local = *addr;
 247                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 248                         iface->dhcpv4_mask = mask;
 249                         return 0;
 250                 }
 251         }
 252
 253         /* Don't allocate IP range for subnets bigger than 28 */
 254         if (iface->addr4[0].prefix > 28) {
 255                 syslog(LOG_ERR, "Auto allocation of DHCP range fails on %s", iface->name);
 256                 return -1;
 257         }
 258
 259         iface->dhcpv4_local = iface->addr4[0].addr.in;
 260         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 261         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 262         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 263
 264         /* Auto allocate ranges */
 265         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
 266                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 267                 iface->dhcpv4_end_ip.s_addr = end | htonl(250);
 268         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
 269                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 270                 iface->dhcpv4_end_ip.s_addr = end | htonl(60);
 271         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
 272                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 273                 iface->dhcpv4_end_ip.s_addr = end | htonl(30);
 274         } else {
 275                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 276                 iface->dhcpv4_end_ip.s_addr = end | htonl(12);
 277         }
 278
 279         return 0;
 280 }
 281
 282 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 283 {
 284         *ptr = ip;
 285         ip->ref_cnt++;
 286 }
 287
 288 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 289 {
 290         struct odhcpd_ref_ip *ip = *ptr;
 291
 292         if (--ip->ref_cnt == 0) {
 293                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 294
 295                 list_del(&ip->head);
 296                 free(ip);
 297         }
 298
 299         *ptr = NULL;
 300 }
 301
 302 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 303 {
 304         struct odhcpd_ref_ip *p;
 305
 306         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 307                 if (addr->s_addr == p->addr.addr.in.s_addr)
 308                         return true;
 309         }
 310
 311         return false;
 312 }
 313
 314 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 315                                 uint32_t mask)
 316 {
 317         struct dhcp_assignment *a = NULL;
 318         struct odhcpd_ref_ip *fr_ip = NULL;
 319
 320         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 321                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 322                     !a->fr_ip &&
 323                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 324                         if (!fr_ip) {
 325                                 fr_ip = calloc(1, sizeof(*fr_ip));
 326                                 if (!fr_ip)
 327                                         break;
 328
 329                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 330                                 fr_ip->addr = *addr;
 331                         }
 332                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 333                 }
 334         }
 335
 336         return fr_ip ? true : false;
 337 }
 338
 339 static void valid_until_cb(struct uloop_timeout *event)
 340 {
 341         struct interface *iface;
 342         time_t now = odhcpd_time();
 343
 344         avl_for_each_element(&interfaces, iface, avl) {
 345                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 346                         continue;
 347
 348                 struct dhcp_assignment *a, *n;
 349                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 350                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 351                                 free_assignment(a);
 352                 }
 353         }
 354         uloop_timeout_set(event, 1000);
 355 }
 356
 357 static void handle_addrlist_change(struct interface *iface)
 358 {
 359         struct odhcpd_ipaddr ip;
 360         struct odhcpd_ref_ip *a;
 361         struct dhcp_assignment *c;
 362         uint32_t mask = iface->dhcpv4_mask.s_addr;
 363
 364         memset(&ip, 0, sizeof(ip));
 365         ip.addr.in = iface->dhcpv4_local;
 366         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 367         ip.broadcast = iface->dhcpv4_bcast;
 368
 369         setup_dhcpv4_addresses(iface);
 370
 371         if ((ip.addr.in.s_addr & mask) ==
 372             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 373                 return;
 374
 375         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 376                 return;
 377
 378         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 379                 return;
 380
 381         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 382
 383         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 384                 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
 385                 return;
 386         }
 387
 388         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 389                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 390                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 391                                 dhcpv4_fr_rand_delay(c);
 392                         else
 393                                 dhcpv4_fr_stop(c);
 394                 }
 395         }
 396 }
 397
 398 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 399 {
 400         switch (reqmsg) {
 401         case (DHCPV4_MSG_DISCOVER):
 402                 return "DHCPV4_MSG_DISCOVER";
 403         case (DHCPV4_MSG_OFFER):
 404                 return "DHCPV4_MSG_OFFER";
 405         case (DHCPV4_MSG_REQUEST):
 406                 return "DHCPV4_MSG_REQUEST";
 407         case (DHCPV4_MSG_DECLINE):
 408                 return "DHCPV4_MSG_DECLINE";
 409         case (DHCPV4_MSG_ACK):
 410                 return "DHCPV4_MSG_ACK";
 411         case (DHCPV4_MSG_NAK):
 412                 return "DHCPV4_MSG_NAK";
 413         case (DHCPV4_MSG_RELEASE):
 414                 return "DHCPV4_MSG_RELEASE";
 415         case (DHCPV4_MSG_INFORM):
 416                 return "DHCPV4_MSG_INFORM";
 417         case (DHCPV4_MSG_FORCERENEW):
 418                 return "DHCPV4_MSG_FORCERENEW";
 419         default:
 420                 return "UNKNOWN";
 421         }
 422 }
 423
 424 static void dhcpv4_free_assignment(struct dhcp_assignment *a)
 425 {
 426         if (a->fr_ip)
 427                 dhcpv4_fr_stop(a);
 428 }
 429
 430 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 431                 uint8_t type, uint8_t len, const void *data)
 432 {
 433         uint8_t *c = *cookie;
 434         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 435         bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END;
 436         int total_len = tag_only ? 1 : 2 + len;
 437
 438         if (*cookie + total_len > end)
 439                 return;
 440
 441         *cookie += total_len;
 442         *c++ = type;
 443
 444         if (tag_only)
 445                 return;
 446
 447         *c++ = len;
 448         memcpy(c, data, len);
 449 }
 450
 451 static void dhcpv4_fr_send(struct dhcp_assignment *a)
 452 {
 453         struct dhcpv4_message fr_msg = {
 454                 .op = DHCPV4_BOOTREPLY,
 455                 .htype = 1,
 456                 .hlen = 6,
 457                 .hops = 0,
 458                 .secs = 0,
 459                 .flags = 0,
 460                 .ciaddr = {INADDR_ANY},
 461                 .yiaddr = {INADDR_ANY},
 462                 .siaddr = {INADDR_ANY},
 463                 .giaddr = {INADDR_ANY},
 464                 .chaddr = {0},
 465                 .sname = {0},
 466                 .file = {0},
 467         };
 468         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 469                 .protocol = 3,
 470                 .algorithm = 1,
 471                 .rdm = 0,
 472                 .replay = {htonl(time(NULL)), htonl(++serial)},
 473                 .type = 2,
 474                 .key = {0},
 475         };
 476         struct interface *iface = a->iface;
 477
 478         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 479         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 480
 481         fr_msg.options[0] = 0x63;
 482         fr_msg.options[1] = 0x82;
 483         fr_msg.options[2] = 0x53;
 484         fr_msg.options[3] = 0x63;
 485
 486         uint8_t *cookie = &fr_msg.options[4];
 487         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 488
 489         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 490         if (a->accept_fr_nonce) {
 491                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 492                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 493                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 494
 495                 md5_ctx_t md5;
 496                 uint8_t secretbytes[64];
 497                 memset(secretbytes, 0, sizeof(secretbytes));
 498                 memcpy(secretbytes, a->key, sizeof(a->key));
 499
 500                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 501                         secretbytes[i] ^= 0x36;
 502
 503                 md5_begin(&md5);
 504                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 505                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 506                 md5_end(auth_o->key, &md5);
 507
 508                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 509                         secretbytes[i] ^= 0x36;
 510                         secretbytes[i] ^= 0x5c;
 511                 }
 512
 513                 md5_begin(&md5);
 514                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 515                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 516                 md5_end(auth_o->key, &md5);
 517         } else {
 518                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 519                                 &a->fr_ip->addr.addr.in.s_addr);
 520                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 521         }
 522
 523         struct sockaddr_in dest;
 524         memset(&dest, 0, sizeof(dest));
 525         dest.sin_family = AF_INET;
 526         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 527         dest.sin_addr.s_addr = a->addr;
 528
 529         if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, PACKET_SIZE(&fr_msg, cookie),
 530                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
 531                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
 532                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 533         else
 534                 syslog(LOG_NOTICE, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
 535                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 536 }
 537
 538 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 539 {
 540         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 541
 542         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 543                 dhcpv4_fr_send(a);
 544                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 545                 a->fr_cnt++;
 546         } else
 547                 dhcpv4_fr_stop(a);
 548 }
 549
 550 static void dhcpv4_fr_start(struct dhcp_assignment *a)
 551 {
 552         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 553         a->fr_timer.cb = dhcpv4_fr_timer;
 554         a->fr_cnt++;
 555
 556         dhcpv4_fr_send(a);
 557 }
 558
 559 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
 560 {
 561         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 562         struct interface *iface = a->iface;
 563
 564         (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
 565 }
 566
 567 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a)
 568 {
 569 #define MIN_DELAY   500
 570 #define MAX_FUZZ    500
 571         int msecs;
 572
 573         odhcpd_urandom(&msecs, sizeof(msecs));
 574
 575         msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
 576
 577         uloop_timeout_set(&a->fr_timer, msecs);
 578         a->fr_timer.cb = dhcpv4_fr_delay_timer;
 579 }
 580
 581 static void dhcpv4_fr_stop(struct dhcp_assignment *a)
 582 {
 583         uloop_timeout_cancel(&a->fr_timer);
 584         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 585         a->fr_cnt = 0;
 586         a->fr_timer.cb = NULL;
 587 }
 588
 589 /* Handler for DHCPv4 messages */
 590 static void handle_dhcpv4(void *addr, void *data, size_t len,
 591                 struct interface *iface, _unused void *dest_addr)
 592 {
 593         struct dhcpv4_message *req = data;
 594
 595         if (!iface->dhcpv4)
 596                 return;
 597
 598         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 599                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 600                 return;
 601
 602         syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
 603
 604         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 605                 syslog(LOG_ERR, "No DHCP range available on %s", iface->name);
 606                 return;
 607         }
 608
 609         int sock = iface->dhcpv4_event.uloop.fd;
 610
 611         struct dhcpv4_message reply = {
 612                 .op = DHCPV4_BOOTREPLY,
 613                 .htype = req->htype,
 614                 .hlen = req->hlen,
 615                 .hops = 0,
 616                 .xid = req->xid,
 617                 .secs = 0,
 618                 .flags = req->flags,
 619                 .ciaddr = {INADDR_ANY},
 620                 .giaddr = req->giaddr,
 621                 .siaddr = iface->dhcpv4_local,
 622         };
 623         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 624
 625         reply.options[0] = 0x63;
 626         reply.options[1] = 0x82;
 627         reply.options[2] = 0x53;
 628         reply.options[3] = 0x63;
 629
 630         uint8_t *cookie = &reply.options[4];
 631         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 632         uint8_t msg = DHCPV4_MSG_ACK;
 633
 634         uint32_t reqaddr = INADDR_ANY;
 635         uint32_t leasetime = 0;
 636         size_t hostname_len = 0;
 637         char hostname[256];
 638         bool accept_fr_nonce = false;
 639         bool incl_fr_opt = false;
 640
 641         uint8_t *start = &req->options[4];
 642         uint8_t *end = ((uint8_t*)data) + len;
 643         struct dhcpv4_option *opt;
 644         dhcpv4_for_each_option(start, end, opt) {
 645                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 646                         reqmsg = opt->data[0];
 647                 else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 648                         hostname_len = opt->len;
 649                         memcpy(hostname, opt->data, hostname_len);
 650                         hostname[hostname_len] = 0;
 651                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 652                         memcpy(&reqaddr, opt->data, 4);
 653                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 654                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 655                                 return;
 656                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 657                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 658                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 659                                 size_t elen = strlen(iface->filter_class);
 660                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 661                                         return; // Ignore from homenet
 662                         }
 663                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 664                         memcpy(&leasetime, opt->data, 4);
 665                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 666                         for (uint8_t i = 0; i < opt->len; i++) {
 667                                 if (opt->data[i] == 1) {
 668                                         accept_fr_nonce = true;
 669                                         break;
 670                                 }
 671                         }
 672
 673                 }
 674         }
 675
 676         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 677             reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 678             reqmsg != DHCPV4_MSG_RELEASE)
 679                 return;
 680
 681         struct dhcp_assignment *a = NULL;
 682         uint32_t serverid = iface->dhcpv4_local.s_addr;
 683         uint32_t fr_serverid = INADDR_ANY;
 684
 685         if (reqmsg != DHCPV4_MSG_INFORM)
 686                 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 687                                  &leasetime, hostname, hostname_len,
 688                                  accept_fr_nonce, &incl_fr_opt, &fr_serverid);
 689
 690         if (!a) {
 691                 if (reqmsg == DHCPV4_MSG_REQUEST)
 692                         msg = DHCPV4_MSG_NAK;
 693                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 694                         return;
 695         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 696                 msg = DHCPV4_MSG_OFFER;
 697         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 698                         ((reqaddr && reqaddr != a->addr) ||
 699                          (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
 700                 msg = DHCPV4_MSG_NAK;
 701                 /*
 702                  * DHCP client requested an IP which we can't offer to him. Probably the
 703                  * client changed the network or the network has been changed. The reply
 704                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 705                  *
 706                  * For modern devices we build an answer that includes a valid IP, like
 707                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 708                  * perform additional DHCP round trips.
 709                  *
 710                  */
 711
 712                 /*
 713                  *
 714                  * Buggy clients do serverid checking in nack messages; therefore set the
 715                  * serverid in nack messages triggered by a previous force renew equal to
 716                  * the server id in use at that time by the server
 717                  *
 718                  */
 719                 if (fr_serverid)
 720                         serverid = fr_serverid;
 721
 722                 if (req->ciaddr.s_addr &&
 723                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 724                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 725                         req->ciaddr.s_addr = INADDR_ANY;
 726         }
 727
 728         syslog(LOG_NOTICE, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
 729                         odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
 730
 731 #ifdef WITH_UBUS
 732         if (reqmsg == DHCPV4_MSG_RELEASE)
 733                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 734                                         &req->ciaddr, hostname, iface->ifname);
 735 #endif
 736         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 737                 return;
 738
 739         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 740         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 741
 742         if (a) {
 743                 uint32_t val;
 744
 745                 reply.yiaddr.s_addr = a->addr;
 746
 747                 val = htonl(leasetime);
 748                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 749
 750                 if (leasetime != UINT32_MAX) {
 751                         val = htonl(500 * leasetime / 1000);
 752                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 753
 754                         val = htonl(875 * leasetime / 1000);
 755                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 756                 }
 757
 758                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 759                                 &iface->dhcpv4_mask.s_addr);
 760
 761                 if (a->hostname)
 762                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 763                                         strlen(a->hostname), a->hostname);
 764
 765                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 766                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 767
 768                 if (incl_fr_opt) {
 769                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 770                                 struct dhcpv4_auth_forcerenew auth = {
 771                                         .protocol = 3,
 772                                         .algorithm = 1,
 773                                         .rdm = 0,
 774                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 775                                         .type = 1,
 776                                         .key = {0},
 777                                 };
 778
 779                                 memcpy(auth.key, a->key, sizeof(auth.key));
 780                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 781                         } else {
 782                                 uint8_t one = 1;
 783                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 784                                         sizeof(one), &one);
 785                         }
 786                 }
 787         }
 788
 789         struct ifreq ifr;
 790
 791         memset(&ifr, 0, sizeof(ifr));
 792         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 793
 794         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 795                 uint16_t mtu = htons(ifr.ifr_mtu);
 796                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 797         }
 798
 799         if (iface->search && iface->search_len <= 255)
 800                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 801                                 iface->search_len, iface->search);
 802         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 803                 uint8_t search_buf[256];
 804                 int len = dn_comp(_res.dnsrch[0], search_buf,
 805                                                 sizeof(search_buf), NULL, NULL);
 806                 if (len > 0)
 807                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 808                                         len, search_buf);
 809         }
 810
 811         if (iface->dhcpv4_router_cnt == 0)
 812                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 813         else
 814                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 815                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 816
 817
 818         if (iface->dhcpv4_dns_cnt == 0)
 819                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 820         else
 821                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 822                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 823
 824
 825         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 826
 827         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 828         if (req->giaddr.s_addr) {
 829                 /*
 830                  * relay agent is configured, send reply to the agent
 831                  */
 832                 dest.sin_addr = req->giaddr;
 833                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 834         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 835                 /*
 836                  * client has existing configuration (ciaddr is set) AND this address is
 837                  * not the address it used for the dhcp message
 838                  */
 839                 dest.sin_addr = req->ciaddr;
 840                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 841         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 842                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 843                 /*
 844                  * client requests a broadcast reply OR we can't offer an IP
 845                  */
 846                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 847                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 848         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 849                 /*
 850                  * client has no previous configuration -> no IP, so we need to reply
 851                  * with a broadcast packet
 852                  */
 853                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 854                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 855         } else {
 856                 struct arpreq arp = {.arp_flags = ATF_COM};
 857
 858                 /*
 859                  * send reply to the newly (in this proccess) allocated IP
 860                  */
 861                 dest.sin_addr = reply.yiaddr;
 862                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 863
 864                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 865                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 866                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 867
 868                 if (ioctl(sock, SIOCSARP, &arp) < 0)
 869                         syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
 870         }
 871
 872         if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT,
 873                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 874                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 875                         dhcpv4_msg_to_string(msg),
 876                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 877                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 878                         inet_ntoa(dest.sin_addr));
 879         else
 880                 syslog(LOG_NOTICE, "Sent %s to %s - %s",
 881                         dhcpv4_msg_to_string(msg),
 882                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 883                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 884                         inet_ntoa(dest.sin_addr));
 885
 886
 887 #ifdef WITH_UBUS
 888         if (msg == DHCPV4_MSG_ACK)
 889                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 890                                         hostname, iface->ifname);
 891 #endif
 892 }
 893
 894 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
 895                           uint32_t raddr)
 896 {
 897         struct dhcp_assignment *c;
 898         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 899         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 900         uint32_t count = end - start + 1;
 901         uint32_t seed = 0;
 902
 903         /* Preconfigured IP address by static lease */
 904         if (a->addr) {
 905                 if (list_empty(&iface->dhcpv4_assignments)) {
 906                         list_add(&a->head, &iface->dhcpv4_assignments);
 907                         return true;
 908                 }
 909
 910                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 911                         if (ntohl(c->addr) > ntohl(a->addr)) {
 912                                 list_add_tail(&a->head, &c->head);
 913                                 return true;
 914                         } else if (ntohl(a->addr) == ntohl(c->addr))
 915                                 return false;
 916                 }
 917         }
 918
 919         /* try to assign the IP the client asked for */
 920         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 921             !config_find_lease_by_ipaddr(raddr)) {
 922                 if (list_empty(&iface->dhcpv4_assignments)) {
 923                         list_add(&a->head, &iface->dhcpv4_assignments);
 924                         goto raddr_out;
 925                 }
 926
 927                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 928                         if (ntohl(raddr) == ntohl(c->addr))
 929                                 break;
 930
 931                         if (ntohl(c->addr) > ntohl(raddr) || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 932                                 list_add_tail(&a->head,
 933                                               ntohl(c->addr) > ntohl(raddr) ? &c->head : &iface->dhcpv4_assignments);
 934 raddr_out:
 935                                 a->addr = raddr;
 936
 937                                 syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
 938                                        ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 939                                        ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 940
 941                                 return true;
 942                         }
 943                 }
 944         }
 945
 946         /* Seed RNG with checksum of hwaddress */
 947         for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
 948                 /* Knuth's multiplicative method */
 949                 uint8_t o = a->hwaddr[i];
 950                 seed += (o*2654435761) % UINT32_MAX;
 951         }
 952
 953         srand(seed);
 954
 955         for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
 956              ++i, try = (((try - start) + 1) % count) + start) {
 957
 958                 if (config_find_lease_by_ipaddr(htonl(try)))
 959                         continue;
 960
 961                 if (list_empty(&iface->dhcpv4_assignments)) {
 962                         list_add(&a->head, &iface->dhcpv4_assignments);
 963                         a->addr = htonl(try);
 964
 965                         syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
 966                                ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 967                                ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 968
 969                         return true;
 970                 }
 971
 972                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 973                         if (try == ntohl(c->addr))
 974                                 break;
 975
 976                         if (ntohl(c->addr) > try || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 977                                 list_add_tail(&a->head,
 978                                               ntohl(c->addr) > try ? &c->head : &iface->dhcpv4_assignments);
 979                                 a->addr = htonl(try);
 980
 981                                 syslog(LOG_INFO, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 982                                         ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 983                                         ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3],
 984                                         i, count);
 985
 986                                 return true;
 987                         }
 988                 }
 989         }
 990
 991         syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
 992         return false;
 993 }
 994
 995
 996 static struct dhcp_assignment*
 997 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
 998              const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
 999              const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
1000              uint32_t *fr_serverid)
1001 {
1002         struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
1003         struct lease *l = config_find_lease_by_mac(mac);
1004         time_t now = odhcpd_time();
1005
1006         if (l && a && a->lease != l) {
1007                 free_assignment(a);
1008                 a = NULL;
1009         }
1010
1011         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1012                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1013                 dhcpv4_fr_stop(a);
1014         }
1015
1016         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1017                 bool assigned = !!a;
1018
1019                 if (!a) {
1020                         if (!iface->no_dynamic_dhcp || l) {
1021                                 /* Create new binding */
1022                                 a = calloc(1, sizeof(*a));
1023                                 if (!a) {
1024                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1025                                                         iface->ifname);
1026                                         return NULL;
1027                                 }
1028                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1029                                 /* Set valid time to 0 for static lease indicating */
1030                                 /* infinite lifetime otherwise current time        */
1031                                 a->valid_until = l ? 0 : now;
1032                                 a->dhcp_free_cb = dhcpv4_free_assignment;
1033                                 a->iface = iface;
1034                                 a->flags = OAF_DHCPV4;
1035                                 a->addr = l ? l->ipaddr : INADDR_ANY;
1036
1037                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1038
1039                                 if (l) {
1040                                         a->flags |= OAF_STATIC;
1041
1042                                         if (l->hostname)
1043                                                 a->hostname = strdup(l->hostname);
1044
1045                                         if (l->leasetime)
1046                                                 a->leasetime = l->leasetime;
1047
1048                                         list_add(&a->lease_list, &l->assignments);
1049                                         a->lease = l;
1050                                 }
1051                         }
1052                 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1053                             (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1054                             !(a->flags & OAF_STATIC)) {
1055                         list_del(&a->head);
1056                         a->addr = INADDR_ANY;
1057
1058                         assigned = dhcpv4_assign(iface, a, reqaddr);
1059                 }
1060
1061                 if (assigned) {
1062                         uint32_t my_leasetime;
1063
1064                         if (a->leasetime)
1065                                 my_leasetime = a->leasetime;
1066                         else
1067                                 my_leasetime = iface->dhcpv4_leasetime;
1068
1069                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1070                                 *leasetime = my_leasetime;
1071
1072                         if (msg == DHCPV4_MSG_DISCOVER) {
1073                                 a->flags &= ~OAF_BOUND;
1074
1075                                 *incl_fr_opt = accept_fr_nonce;
1076                                 if (!(a->flags & OAF_STATIC))
1077                                         a->valid_until = now;
1078                         } else {
1079                                 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1080                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1081                                         if (a->hostname) {
1082                                                 memcpy(a->hostname, hostname, hostname_len);
1083                                                 a->hostname[hostname_len] = 0;
1084
1085                                                 if (odhcpd_valid_hostname(a->hostname))
1086                                                         a->flags &= ~OAF_BROKEN_HOSTNAME;
1087                                                 else
1088                                                         a->flags |= OAF_BROKEN_HOSTNAME;
1089                                         }
1090                                 }
1091
1092                                 if (!(a->flags & OAF_BOUND)) {
1093                                         a->accept_fr_nonce = accept_fr_nonce;
1094                                         *incl_fr_opt = accept_fr_nonce;
1095                                         odhcpd_urandom(a->key, sizeof(a->key));
1096                                         a->flags |= OAF_BOUND;
1097                                 } else
1098                                         *incl_fr_opt = false;
1099
1100                                 if (!(a->flags & OAF_STATIC))
1101                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1102                         }
1103                 } else if (!assigned && a) {
1104                         /* Cleanup failed assignment */
1105                         free_assignment(a);
1106                         a = NULL;
1107                 }
1108
1109         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1110                 a->flags &= ~OAF_BOUND;
1111
1112                 if (!(a->flags & OAF_STATIC))
1113                         a->valid_until = now - 1;
1114
1115         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1116                 a->flags &= ~OAF_BOUND;
1117
1118                 if (!(a->flags & OAF_STATIC)) {
1119                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1120                         a->valid_until = now + 3600; /* Block address for 1h */
1121                 }
1122         }
1123
1124         dhcpv6_ia_write_statefile();
1125
1126         return a;
1127 }