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) {           /* /24, 150 of 256, [100..249] */
 267                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 268                 iface->dhcpv4_end_ip.s_addr = end | htonl(100 + 150 - 1);
 269         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff80) {    /* /25, 100 of 128, [20..119] */
 270                 iface->dhcpv4_start_ip.s_addr = start | htonl(20);
 271                 iface->dhcpv4_end_ip.s_addr = end | htonl(20 + 100 - 1);
 272         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {    /* /26, 50 of 64, [10..59] */
 273                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 274                 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 50 - 1);
 275         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {    /* /27, 20 of 32, [10..29] */
 276                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 277                 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 20 - 1);
 278         } else {                                                        /* /28, 10 of 16, [3..12] */
 279                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 280                 iface->dhcpv4_end_ip.s_addr = end | htonl(3 + 10 - 1);
 281         }
 282
 283         return 0;
 284 }
 285
 286 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 287 {
 288         *ptr = ip;
 289         ip->ref_cnt++;
 290 }
 291
 292 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 293 {
 294         struct odhcpd_ref_ip *ip = *ptr;
 295
 296         if (--ip->ref_cnt == 0) {
 297                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 298
 299                 list_del(&ip->head);
 300                 free(ip);
 301         }
 302
 303         *ptr = NULL;
 304 }
 305
 306 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 307 {
 308         struct odhcpd_ref_ip *p;
 309
 310         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 311                 if (addr->s_addr == p->addr.addr.in.s_addr)
 312                         return true;
 313         }
 314
 315         return false;
 316 }
 317
 318 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 319                                 uint32_t mask)
 320 {
 321         struct dhcp_assignment *a = NULL;
 322         struct odhcpd_ref_ip *fr_ip = NULL;
 323
 324         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 325                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 326                     !a->fr_ip &&
 327                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 328                         if (!fr_ip) {
 329                                 fr_ip = calloc(1, sizeof(*fr_ip));
 330                                 if (!fr_ip)
 331                                         break;
 332
 333                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 334                                 fr_ip->addr = *addr;
 335                         }
 336                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 337                 }
 338         }
 339
 340         return fr_ip ? true : false;
 341 }
 342
 343 static void valid_until_cb(struct uloop_timeout *event)
 344 {
 345         struct interface *iface;
 346         time_t now = odhcpd_time();
 347
 348         avl_for_each_element(&interfaces, iface, avl) {
 349                 if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
 350                         continue;
 351
 352                 struct dhcp_assignment *a, *n;
 353                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 354                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 355                                 free_assignment(a);
 356                 }
 357         }
 358         uloop_timeout_set(event, 1000);
 359 }
 360
 361 static void handle_addrlist_change(struct interface *iface)
 362 {
 363         struct odhcpd_ipaddr ip;
 364         struct odhcpd_ref_ip *a;
 365         struct dhcp_assignment *c;
 366         uint32_t mask = iface->dhcpv4_mask.s_addr;
 367
 368         memset(&ip, 0, sizeof(ip));
 369         ip.addr.in = iface->dhcpv4_local;
 370         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 371         ip.broadcast = iface->dhcpv4_bcast;
 372
 373         setup_dhcpv4_addresses(iface);
 374
 375         if ((ip.addr.in.s_addr & mask) ==
 376             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 377                 return;
 378
 379         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 380                 return;
 381
 382         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 383                 return;
 384
 385         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 386
 387         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 388                 syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
 389                 return;
 390         }
 391
 392         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 393                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 394                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 395                                 dhcpv4_fr_rand_delay(c);
 396                         else
 397                                 dhcpv4_fr_stop(c);
 398                 }
 399         }
 400 }
 401
 402 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 403 {
 404         switch (reqmsg) {
 405         case (DHCPV4_MSG_DISCOVER):
 406                 return "DHCPV4_MSG_DISCOVER";
 407         case (DHCPV4_MSG_OFFER):
 408                 return "DHCPV4_MSG_OFFER";
 409         case (DHCPV4_MSG_REQUEST):
 410                 return "DHCPV4_MSG_REQUEST";
 411         case (DHCPV4_MSG_DECLINE):
 412                 return "DHCPV4_MSG_DECLINE";
 413         case (DHCPV4_MSG_ACK):
 414                 return "DHCPV4_MSG_ACK";
 415         case (DHCPV4_MSG_NAK):
 416                 return "DHCPV4_MSG_NAK";
 417         case (DHCPV4_MSG_RELEASE):
 418                 return "DHCPV4_MSG_RELEASE";
 419         case (DHCPV4_MSG_INFORM):
 420                 return "DHCPV4_MSG_INFORM";
 421         case (DHCPV4_MSG_FORCERENEW):
 422                 return "DHCPV4_MSG_FORCERENEW";
 423         default:
 424                 return "UNKNOWN";
 425         }
 426 }
 427
 428 static void dhcpv4_free_assignment(struct dhcp_assignment *a)
 429 {
 430         if (a->fr_ip)
 431                 dhcpv4_fr_stop(a);
 432 }
 433
 434 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 435                 uint8_t type, uint8_t len, const void *data)
 436 {
 437         uint8_t *c = *cookie;
 438         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 439         bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END;
 440         int total_len = tag_only ? 1 : 2 + len;
 441
 442         if (*cookie + total_len > end)
 443                 return;
 444
 445         *cookie += total_len;
 446         *c++ = type;
 447
 448         if (tag_only)
 449                 return;
 450
 451         *c++ = len;
 452         memcpy(c, data, len);
 453 }
 454
 455 static void dhcpv4_fr_send(struct dhcp_assignment *a)
 456 {
 457         struct dhcpv4_message fr_msg = {
 458                 .op = DHCPV4_BOOTREPLY,
 459                 .htype = 1,
 460                 .hlen = 6,
 461                 .hops = 0,
 462                 .secs = 0,
 463                 .flags = 0,
 464                 .ciaddr = {INADDR_ANY},
 465                 .yiaddr = {INADDR_ANY},
 466                 .siaddr = {INADDR_ANY},
 467                 .giaddr = {INADDR_ANY},
 468                 .chaddr = {0},
 469                 .sname = {0},
 470                 .file = {0},
 471         };
 472         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 473                 .protocol = 3,
 474                 .algorithm = 1,
 475                 .rdm = 0,
 476                 .replay = {htonl(time(NULL)), htonl(++serial)},
 477                 .type = 2,
 478                 .key = {0},
 479         };
 480         struct interface *iface = a->iface;
 481
 482         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 483         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 484
 485         fr_msg.options[0] = 0x63;
 486         fr_msg.options[1] = 0x82;
 487         fr_msg.options[2] = 0x53;
 488         fr_msg.options[3] = 0x63;
 489
 490         uint8_t *cookie = &fr_msg.options[4];
 491         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 492
 493         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 494         if (a->accept_fr_nonce) {
 495                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 496                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 497                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 498
 499                 md5_ctx_t md5;
 500                 uint8_t secretbytes[64];
 501                 memset(secretbytes, 0, sizeof(secretbytes));
 502                 memcpy(secretbytes, a->key, sizeof(a->key));
 503
 504                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 505                         secretbytes[i] ^= 0x36;
 506
 507                 md5_begin(&md5);
 508                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 509                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 510                 md5_end(auth_o->key, &md5);
 511
 512                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 513                         secretbytes[i] ^= 0x36;
 514                         secretbytes[i] ^= 0x5c;
 515                 }
 516
 517                 md5_begin(&md5);
 518                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 519                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 520                 md5_end(auth_o->key, &md5);
 521         } else {
 522                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 523                                 &a->fr_ip->addr.addr.in.s_addr);
 524                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 525         }
 526
 527         struct sockaddr_in dest;
 528         memset(&dest, 0, sizeof(dest));
 529         dest.sin_family = AF_INET;
 530         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 531         dest.sin_addr.s_addr = a->addr;
 532
 533         if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, PACKET_SIZE(&fr_msg, cookie),
 534                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
 535                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
 536                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 537         else
 538                 syslog(LOG_NOTICE, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
 539                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 540 }
 541
 542 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 543 {
 544         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 545
 546         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 547                 dhcpv4_fr_send(a);
 548                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 549                 a->fr_cnt++;
 550         } else
 551                 dhcpv4_fr_stop(a);
 552 }
 553
 554 static void dhcpv4_fr_start(struct dhcp_assignment *a)
 555 {
 556         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 557         a->fr_timer.cb = dhcpv4_fr_timer;
 558         a->fr_cnt++;
 559
 560         dhcpv4_fr_send(a);
 561 }
 562
 563 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
 564 {
 565         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 566         struct interface *iface = a->iface;
 567
 568         (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
 569 }
 570
 571 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a)
 572 {
 573 #define MIN_DELAY   500
 574 #define MAX_FUZZ    500
 575         int msecs;
 576
 577         odhcpd_urandom(&msecs, sizeof(msecs));
 578
 579         msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
 580
 581         uloop_timeout_set(&a->fr_timer, msecs);
 582         a->fr_timer.cb = dhcpv4_fr_delay_timer;
 583 }
 584
 585 static void dhcpv4_fr_stop(struct dhcp_assignment *a)
 586 {
 587         uloop_timeout_cancel(&a->fr_timer);
 588         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 589         a->fr_cnt = 0;
 590         a->fr_timer.cb = NULL;
 591 }
 592
 593 /* Handler for DHCPv4 messages */
 594 static void handle_dhcpv4(void *addr, void *data, size_t len,
 595                 struct interface *iface, _unused void *dest_addr)
 596 {
 597         struct dhcpv4_message *req = data;
 598
 599         if (!iface->dhcpv4)
 600                 return;
 601
 602         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 603                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 604                 return;
 605
 606         syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
 607
 608         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 609                 syslog(LOG_ERR, "No DHCP range available on %s", iface->name);
 610                 return;
 611         }
 612
 613         int sock = iface->dhcpv4_event.uloop.fd;
 614
 615         struct dhcpv4_message reply = {
 616                 .op = DHCPV4_BOOTREPLY,
 617                 .htype = req->htype,
 618                 .hlen = req->hlen,
 619                 .hops = 0,
 620                 .xid = req->xid,
 621                 .secs = 0,
 622                 .flags = req->flags,
 623                 .ciaddr = {INADDR_ANY},
 624                 .giaddr = req->giaddr,
 625                 .siaddr = iface->dhcpv4_local,
 626         };
 627         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 628
 629         reply.options[0] = 0x63;
 630         reply.options[1] = 0x82;
 631         reply.options[2] = 0x53;
 632         reply.options[3] = 0x63;
 633
 634         uint8_t *cookie = &reply.options[4];
 635         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 636         uint8_t msg = DHCPV4_MSG_ACK;
 637
 638         uint32_t reqaddr = INADDR_ANY;
 639         uint32_t leasetime = 0;
 640         size_t hostname_len = 0;
 641         size_t reqopts_len = 0;
 642         char hostname[256];
 643         char reqopts[256];
 644         bool accept_fr_nonce = false;
 645         bool incl_fr_opt = false;
 646
 647         uint8_t *start = &req->options[4];
 648         uint8_t *end = ((uint8_t*)data) + len;
 649         struct dhcpv4_option *opt;
 650         dhcpv4_for_each_option(start, end, opt) {
 651                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 652                         reqmsg = opt->data[0];
 653                 else if (opt->type == DHCPV4_OPT_REQOPTS && opt->len > 0) {
 654                         reqopts_len = opt->len;
 655                         memcpy(reqopts, opt->data, reqopts_len);
 656                         reqopts[reqopts_len] = 0;
 657                 } else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 658                         hostname_len = opt->len;
 659                         memcpy(hostname, opt->data, hostname_len);
 660                         hostname[hostname_len] = 0;
 661                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 662                         memcpy(&reqaddr, opt->data, 4);
 663                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 664                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 665                                 return;
 666                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 667                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 668                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 669                                 size_t elen = strlen(iface->filter_class);
 670                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 671                                         return; // Ignore from homenet
 672                         }
 673                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 674                         memcpy(&leasetime, opt->data, 4);
 675                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 676                         for (uint8_t i = 0; i < opt->len; i++) {
 677                                 if (opt->data[i] == 1) {
 678                                         accept_fr_nonce = true;
 679                                         break;
 680                                 }
 681                         }
 682
 683                 }
 684         }
 685
 686         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 687             reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 688             reqmsg != DHCPV4_MSG_RELEASE)
 689                 return;
 690
 691         struct dhcp_assignment *a = NULL;
 692         uint32_t serverid = iface->dhcpv4_local.s_addr;
 693         uint32_t fr_serverid = INADDR_ANY;
 694
 695         if (reqmsg != DHCPV4_MSG_INFORM)
 696                 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 697                                  &leasetime, hostname, hostname_len,
 698                                  accept_fr_nonce, &incl_fr_opt, &fr_serverid,
 699                                  reqopts, reqopts_len);
 700
 701         if (!a) {
 702                 if (reqmsg == DHCPV4_MSG_REQUEST)
 703                         msg = DHCPV4_MSG_NAK;
 704                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 705                         return;
 706         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 707                 msg = DHCPV4_MSG_OFFER;
 708         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 709                         ((reqaddr && reqaddr != a->addr) ||
 710                          (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
 711                 msg = DHCPV4_MSG_NAK;
 712                 /*
 713                  * DHCP client requested an IP which we can't offer to him. Probably the
 714                  * client changed the network or the network has been changed. The reply
 715                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 716                  *
 717                  * For modern devices we build an answer that includes a valid IP, like
 718                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 719                  * perform additional DHCP round trips.
 720                  *
 721                  */
 722
 723                 /*
 724                  *
 725                  * Buggy clients do serverid checking in nack messages; therefore set the
 726                  * serverid in nack messages triggered by a previous force renew equal to
 727                  * the server id in use at that time by the server
 728                  *
 729                  */
 730                 if (fr_serverid)
 731                         serverid = fr_serverid;
 732
 733                 if (req->ciaddr.s_addr &&
 734                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 735                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 736                         req->ciaddr.s_addr = INADDR_ANY;
 737         }
 738
 739         syslog(LOG_NOTICE, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
 740                         odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
 741
 742 #ifdef WITH_UBUS
 743         if (reqmsg == DHCPV4_MSG_RELEASE)
 744                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 745                                         &req->ciaddr, hostname, iface->ifname);
 746 #endif
 747         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 748                 return;
 749
 750         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 751         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 752
 753         if (a) {
 754                 uint32_t val;
 755
 756                 reply.yiaddr.s_addr = a->addr;
 757
 758                 val = htonl(leasetime);
 759                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 760
 761                 if (leasetime != UINT32_MAX) {
 762                         val = htonl(500 * leasetime / 1000);
 763                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 764
 765                         val = htonl(875 * leasetime / 1000);
 766                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 767                 }
 768
 769                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 770                                 &iface->dhcpv4_mask.s_addr);
 771
 772                 if (a->hostname)
 773                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 774                                         strlen(a->hostname), a->hostname);
 775
 776                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 777                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 778
 779                 if (incl_fr_opt) {
 780                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 781                                 struct dhcpv4_auth_forcerenew auth = {
 782                                         .protocol = 3,
 783                                         .algorithm = 1,
 784                                         .rdm = 0,
 785                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 786                                         .type = 1,
 787                                         .key = {0},
 788                                 };
 789
 790                                 memcpy(auth.key, a->key, sizeof(auth.key));
 791                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 792                         } else {
 793                                 uint8_t one = 1;
 794                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 795                                         sizeof(one), &one);
 796                         }
 797                 }
 798         }
 799
 800         struct ifreq ifr;
 801
 802         memset(&ifr, 0, sizeof(ifr));
 803         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 804
 805         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 806                 uint16_t mtu = htons(ifr.ifr_mtu);
 807                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 808         }
 809
 810         if (iface->search && iface->search_len <= 255)
 811                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 812                                 iface->search_len, iface->search);
 813         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 814                 uint8_t search_buf[256];
 815                 int len = dn_comp(_res.dnsrch[0], search_buf,
 816                                                 sizeof(search_buf), NULL, NULL);
 817                 if (len > 0)
 818                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 819                                         len, search_buf);
 820         }
 821
 822         if (iface->dhcpv4_router_cnt == 0)
 823                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 824         else
 825                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 826                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 827
 828
 829         if (iface->dhcpv4_dns_cnt == 0)
 830                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 831         else
 832                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 833                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 834
 835
 836         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 837
 838         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 839         if (req->giaddr.s_addr) {
 840                 /*
 841                  * relay agent is configured, send reply to the agent
 842                  */
 843                 dest.sin_addr = req->giaddr;
 844                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 845         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 846                 /*
 847                  * client has existing configuration (ciaddr is set) AND this address is
 848                  * not the address it used for the dhcp message
 849                  */
 850                 dest.sin_addr = req->ciaddr;
 851                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 852         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 853                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 854                 /*
 855                  * client requests a broadcast reply OR we can't offer an IP
 856                  */
 857                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 858                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 859         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 860                 /*
 861                  * client has no previous configuration -> no IP, so we need to reply
 862                  * with a broadcast packet
 863                  */
 864                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 865                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 866         } else {
 867                 struct arpreq arp = {.arp_flags = ATF_COM};
 868
 869                 /*
 870                  * send reply to the newly (in this proccess) allocated IP
 871                  */
 872                 dest.sin_addr = reply.yiaddr;
 873                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 874
 875                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 876                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 877                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 878
 879                 if (ioctl(sock, SIOCSARP, &arp) < 0)
 880                         syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
 881         }
 882
 883         if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT,
 884                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 885                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 886                         dhcpv4_msg_to_string(msg),
 887                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 888                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 889                         inet_ntoa(dest.sin_addr));
 890         else
 891                 syslog(LOG_NOTICE, "Sent %s to %s - %s",
 892                         dhcpv4_msg_to_string(msg),
 893                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 894                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 895                         inet_ntoa(dest.sin_addr));
 896
 897
 898 #ifdef WITH_UBUS
 899         if (msg == DHCPV4_MSG_ACK)
 900                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 901                                         hostname, iface->ifname);
 902 #endif
 903 }
 904
 905 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
 906                           uint32_t raddr)
 907 {
 908         struct dhcp_assignment *c;
 909         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 910         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 911         uint32_t count = end - start + 1;
 912         uint32_t seed = 0;
 913
 914         /* Preconfigured IP address by static lease */
 915         if (a->addr) {
 916                 if (list_empty(&iface->dhcpv4_assignments)) {
 917                         list_add(&a->head, &iface->dhcpv4_assignments);
 918                         return true;
 919                 }
 920
 921                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 922                         if (ntohl(c->addr) > ntohl(a->addr)) {
 923                                 list_add_tail(&a->head, &c->head);
 924                                 return true;
 925                         } else if (ntohl(a->addr) == ntohl(c->addr))
 926                                 return false;
 927                 }
 928         }
 929
 930         /* try to assign the IP the client asked for */
 931         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 932             !config_find_lease_by_ipaddr(raddr)) {
 933                 if (list_empty(&iface->dhcpv4_assignments)) {
 934                         list_add(&a->head, &iface->dhcpv4_assignments);
 935                         goto raddr_out;
 936                 }
 937
 938                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 939                         if (ntohl(raddr) == ntohl(c->addr))
 940                                 break;
 941
 942                         if (ntohl(c->addr) > ntohl(raddr) || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 943                                 list_add_tail(&a->head,
 944                                               ntohl(c->addr) > ntohl(raddr) ? &c->head : &iface->dhcpv4_assignments);
 945 raddr_out:
 946                                 a->addr = raddr;
 947
 948                                 syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
 949                                        ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 950                                        ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 951
 952                                 return true;
 953                         }
 954                 }
 955         }
 956
 957         /* Seed RNG with checksum of hwaddress */
 958         for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
 959                 /* Knuth's multiplicative method */
 960                 uint8_t o = a->hwaddr[i];
 961                 seed += (o*2654435761) % UINT32_MAX;
 962         }
 963
 964         srand(seed);
 965
 966         for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
 967              ++i, try = (((try - start) + 1) % count) + start) {
 968
 969                 if (config_find_lease_by_ipaddr(htonl(try)))
 970                         continue;
 971
 972                 if (list_empty(&iface->dhcpv4_assignments)) {
 973                         list_add(&a->head, &iface->dhcpv4_assignments);
 974                         a->addr = htonl(try);
 975
 976                         syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
 977                                ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 978                                ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3]);
 979
 980                         return true;
 981                 }
 982
 983                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 984                         if (try == ntohl(c->addr))
 985                                 break;
 986
 987                         if (ntohl(c->addr) > try || list_is_last(&c->head, &iface->dhcpv4_assignments)) {
 988                                 list_add_tail(&a->head,
 989                                               ntohl(c->addr) > try ? &c->head : &iface->dhcpv4_assignments);
 990                                 a->addr = htonl(try);
 991
 992                                 syslog(LOG_INFO, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
 993                                         ((uint8_t *)&a->addr)[0], ((uint8_t *)&a->addr)[1],
 994                                         ((uint8_t *)&a->addr)[2], ((uint8_t *)&a->addr)[3],
 995                                         i, count);
 996
 997                                 return true;
 998                         }
 999                 }
1000         }
1001
1002         syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
1003         return false;
1004 }
1005
1006
1007 static struct dhcp_assignment*
1008 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
1009              const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
1010              const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
1011              uint32_t *fr_serverid, const char* reqopts, const size_t reqopts_len)
1012 {
1013         struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
1014         struct lease *l = config_find_lease_by_mac(mac);
1015         time_t now = odhcpd_time();
1016
1017         if (l && a && a->lease != l) {
1018                 free_assignment(a);
1019                 a = NULL;
1020         }
1021
1022         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1023                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1024                 dhcpv4_fr_stop(a);
1025         }
1026
1027         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1028                 bool assigned = !!a;
1029
1030                 if (!a) {
1031                         if (!iface->no_dynamic_dhcp || l) {
1032                                 /* Create new binding */
1033                                 a = calloc(1, sizeof(*a));
1034                                 if (!a) {
1035                                         syslog(LOG_ERR, "Failed to calloc binding on interface %s",
1036                                                         iface->ifname);
1037                                         return NULL;
1038                                 }
1039                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1040                                 /* Set valid time to 0 for static lease indicating */
1041                                 /* infinite lifetime otherwise current time        */
1042                                 a->valid_until = l ? 0 : now;
1043                                 a->dhcp_free_cb = dhcpv4_free_assignment;
1044                                 a->iface = iface;
1045                                 a->flags = OAF_DHCPV4;
1046                                 a->addr = l ? l->ipaddr : INADDR_ANY;
1047
1048                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1049
1050                                 if (l) {
1051                                         a->flags |= OAF_STATIC;
1052
1053                                         if (l->hostname)
1054                                                 a->hostname = strdup(l->hostname);
1055
1056                                         if (l->leasetime)
1057                                                 a->leasetime = l->leasetime;
1058
1059                                         list_add(&a->lease_list, &l->assignments);
1060                                         a->lease = l;
1061                                 }
1062                         }
1063                 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1064                             (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1065                             !(a->flags & OAF_STATIC)) {
1066                         list_del(&a->head);
1067                         a->addr = INADDR_ANY;
1068
1069                         assigned = dhcpv4_assign(iface, a, reqaddr);
1070                 }
1071
1072                 if (assigned) {
1073                         uint32_t my_leasetime;
1074
1075                         if (a->leasetime)
1076                                 my_leasetime = a->leasetime;
1077                         else
1078                                 my_leasetime = iface->dhcpv4_leasetime;
1079
1080                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1081                                 *leasetime = my_leasetime;
1082
1083                         if (msg == DHCPV4_MSG_DISCOVER) {
1084                                 a->flags &= ~OAF_BOUND;
1085
1086                                 *incl_fr_opt = accept_fr_nonce;
1087                                 if (!(a->flags & OAF_STATIC))
1088                                         a->valid_until = now;
1089                         } else {
1090                                 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1091                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1092                                         if (a->hostname) {
1093                                                 memcpy(a->hostname, hostname, hostname_len);
1094                                                 a->hostname[hostname_len] = 0;
1095
1096                                                 if (odhcpd_valid_hostname(a->hostname))
1097                                                         a->flags &= ~OAF_BROKEN_HOSTNAME;
1098                                                 else
1099                                                         a->flags |= OAF_BROKEN_HOSTNAME;
1100                                         }
1101                                 }
1102
1103                                 if (reqopts_len > 0) {
1104                                         a->reqopts = realloc(a->reqopts, reqopts_len + 1);
1105                                         if (a->reqopts) {
1106                                                 memcpy(a->reqopts, reqopts, reqopts_len);
1107                                                 a->reqopts[reqopts_len] = 0;
1108                                         }
1109                                 }
1110
1111                                 if (!(a->flags & OAF_BOUND)) {
1112                                         a->accept_fr_nonce = accept_fr_nonce;
1113                                         *incl_fr_opt = accept_fr_nonce;
1114                                         odhcpd_urandom(a->key, sizeof(a->key));
1115                                         a->flags |= OAF_BOUND;
1116                                 } else
1117                                         *incl_fr_opt = false;
1118
1119                                 if (!(a->flags & OAF_STATIC))
1120                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1121                         }
1122                 } else if (!assigned && a) {
1123                         /* Cleanup failed assignment */
1124                         free_assignment(a);
1125                         a = NULL;
1126                 }
1127
1128         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1129                 a->flags &= ~OAF_BOUND;
1130
1131                 if (!(a->flags & OAF_STATIC))
1132                         a->valid_until = now - 1;
1133
1134         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1135                 a->flags &= ~OAF_BOUND;
1136
1137                 if (!(a->flags & OAF_STATIC)) {
1138                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1139                         a->valid_until = now + 3600; /* Block address for 1h */
1140                 }
1141         }
1142
1143         dhcpv6_ia_write_statefile();
1144
1145         return a;
1146 }