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         enable = enable && (iface->dhcpv4 != MODE_DISABLED);
  81
  82         if (iface->dhcpv4_event.uloop.fd >= 0) {
  83                 uloop_fd_delete(&iface->dhcpv4_event.uloop);
  84                 close(iface->dhcpv4_event.uloop.fd);
  85                 iface->dhcpv4_event.uloop.fd = -1;
  86         }
  87
  88         if (enable) {
  89                 struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
  90                                         {INADDR_ANY}, {0}};
  91                 int val = 1;
  92
  93                 iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  94                 if (iface->dhcpv4_event.uloop.fd < 0) {
  95                         syslog(LOG_ERR, "socket(AF_INET): %m");
  96                         ret = -1;
  97                         goto out;
  98                 }
  99
 100                 /* Basic IPv4 configuration */
 101                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
 102                                         &val, sizeof(val)) < 0) {
 103                         syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
 104                         ret = -1;
 105                         goto out;
 106                 }
 107
 108                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
 109                                         &val, sizeof(val)) < 0) {
 110                         syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
 111                         ret = -1;
 112                         goto out;
 113                 }
 114
 115                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
 116                                         &val, sizeof(val)) < 0) {
 117                         syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
 118                         ret = -1;
 119                         goto out;
 120                 }
 121
 122                 val = IPTOS_PREC_INTERNETCONTROL;
 123                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
 124                                         &val, sizeof(val)) < 0) {
 125                         syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
 126                         ret = -1;
 127                         goto out;
 128                 }
 129
 130                 val = IP_PMTUDISC_DONT;
 131                 if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
 132                                         &val, sizeof(val)) < 0) {
 133                         syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
 134                         ret = -1;
 135                         goto out;
 136                 }
 137
 138                 if (setsockopt(iface->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 139                                         iface->ifname, strlen(iface->ifname)) < 0) {
 140                         syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 141                         ret = -1;
 142                         goto out;
 143                 }
 144
 145                 if (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
 146                                         sizeof(bind_addr)) < 0) {
 147                         syslog(LOG_ERR, "bind(): %m");
 148                         ret = -1;
 149                         goto out;
 150                 }
 151
 152                 if (setup_dhcpv4_addresses(iface) < 0) {
 153                         ret = -1;
 154                         goto out;
 155                 }
 156
 157                 iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
 158                 odhcpd_register(&iface->dhcpv4_event);
 159         } else {
 160                 while (!list_empty(&iface->dhcpv4_assignments))
 161                         free_assignment(list_first_entry(&iface->dhcpv4_assignments,
 162                                                         struct dhcp_assignment, head));
 163         }
 164
 165 out:
 166         if (ret < 0 && iface->dhcpv4_event.uloop.fd >= 0) {
 167                 close(iface->dhcpv4_event.uloop.fd);
 168                 iface->dhcpv4_event.uloop.fd = -1;
 169         }
 170
 171         return ret;
 172 }
 173
 174
 175 static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 176 {
 177         struct interface *iface = info->iface;
 178
 179         if (!iface || iface->dhcpv4 == MODE_DISABLED)
 180                 return;
 181
 182         switch (event) {
 183         case NETEV_IFINDEX_CHANGE:
 184                 dhcpv4_setup_interface(iface, true);
 185                 break;
 186         case NETEV_ADDRLIST_CHANGE:
 187                 handle_addrlist_change(iface);
 188                 break;
 189         default:
 190                 break;
 191         }
 192 }
 193
 194 static struct dhcp_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
 195 {
 196         struct dhcp_assignment *a;
 197
 198         list_for_each_entry(a, &iface->dhcpv4_assignments, head)
 199                 if (!memcmp(a->hwaddr, hwaddr, 6))
 200                         return a;
 201
 202         return NULL;
 203 }
 204
 205 static int setup_dhcpv4_addresses(struct interface *iface)
 206 {
 207         iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
 208         iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
 209         iface->dhcpv4_local.s_addr = INADDR_ANY;
 210         iface->dhcpv4_bcast.s_addr = INADDR_ANY;
 211         iface->dhcpv4_mask.s_addr = INADDR_ANY;
 212
 213         /* Sanity checks */
 214         if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
 215             iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
 216             ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
 217                 syslog(LOG_WARNING, "Invalid DHCP range for %s", iface->name);
 218                 return -1;
 219         }
 220
 221         if (!iface->addr4_len) {
 222                 syslog(LOG_WARNING, "No network(s) available on %s", iface->name);
 223                 return -1;
 224         }
 225
 226         uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
 227         uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
 228
 229         for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
 230                 struct in_addr *addr = &iface->addr4[i].addr.in;
 231                 struct in_addr mask;
 232
 233                 if (addr_is_fr_ip(iface, addr))
 234                         continue;
 235
 236                 odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
 237                 if ((start & ntohl(~mask.s_addr)) == start &&
 238                                 (end & ntohl(~mask.s_addr)) == end &&
 239                                 end < ntohl(~mask.s_addr)) {    /* Exclude broadcast address */
 240                         iface->dhcpv4_start_ip.s_addr = htonl(start) |
 241                                                         (addr->s_addr & mask.s_addr);
 242                         iface->dhcpv4_end_ip.s_addr = htonl(end) |
 243                                                         (addr->s_addr & mask.s_addr);
 244                         iface->dhcpv4_local = *addr;
 245                         iface->dhcpv4_bcast = iface->addr4[i].broadcast;
 246                         iface->dhcpv4_mask = mask;
 247                         return 0;
 248                 }
 249         }
 250
 251         /* Don't allocate IP range for subnets bigger than 28 */
 252         if (iface->addr4[0].prefix > 28) {
 253                 syslog(LOG_WARNING, "Auto allocation of DHCP range fails on %s", iface->name);
 254                 return -1;
 255         }
 256
 257         iface->dhcpv4_local = iface->addr4[0].addr.in;
 258         iface->dhcpv4_bcast = iface->addr4[0].broadcast;
 259         odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
 260         end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
 261
 262         /* Auto allocate ranges */
 263         if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {           /* /24, 150 of 256, [100..249] */
 264                 iface->dhcpv4_start_ip.s_addr = start | htonl(100);
 265                 iface->dhcpv4_end_ip.s_addr = end | htonl(100 + 150 - 1);
 266         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff80) {    /* /25, 100 of 128, [20..119] */
 267                 iface->dhcpv4_start_ip.s_addr = start | htonl(20);
 268                 iface->dhcpv4_end_ip.s_addr = end | htonl(20 + 100 - 1);
 269         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {    /* /26, 50 of 64, [10..59] */
 270                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 271                 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 50 - 1);
 272         } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {    /* /27, 20 of 32, [10..29] */
 273                 iface->dhcpv4_start_ip.s_addr = start | htonl(10);
 274                 iface->dhcpv4_end_ip.s_addr = end | htonl(10 + 20 - 1);
 275         } else {                                                        /* /28, 10 of 16, [3..12] */
 276                 iface->dhcpv4_start_ip.s_addr = start | htonl(3);
 277                 iface->dhcpv4_end_ip.s_addr = end | htonl(3 + 10 - 1);
 278         }
 279
 280         return 0;
 281 }
 282
 283 static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
 284 {
 285         *ptr = ip;
 286         ip->ref_cnt++;
 287 }
 288
 289 static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
 290 {
 291         struct odhcpd_ref_ip *ip = *ptr;
 292
 293         if (--ip->ref_cnt == 0) {
 294                 netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
 295
 296                 list_del(&ip->head);
 297                 free(ip);
 298         }
 299
 300         *ptr = NULL;
 301 }
 302
 303 static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
 304 {
 305         struct odhcpd_ref_ip *p;
 306
 307         list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
 308                 if (addr->s_addr == p->addr.addr.in.s_addr)
 309                         return true;
 310         }
 311
 312         return false;
 313 }
 314
 315 static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
 316                                 uint32_t mask)
 317 {
 318         struct dhcp_assignment *a = NULL;
 319         struct odhcpd_ref_ip *fr_ip = NULL;
 320
 321         list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
 322                 if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
 323                     !a->fr_ip &&
 324                     ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
 325                         if (!fr_ip) {
 326                                 fr_ip = calloc(1, sizeof(*fr_ip));
 327                                 if (!fr_ip)
 328                                         break;
 329
 330                                 list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
 331                                 fr_ip->addr = *addr;
 332                         }
 333                         inc_ref_cnt_ip(&a->fr_ip, fr_ip);
 334                 }
 335         }
 336
 337         return fr_ip ? true : false;
 338 }
 339
 340 static void valid_until_cb(struct uloop_timeout *event)
 341 {
 342         struct interface *iface;
 343         time_t now = odhcpd_time();
 344
 345         avl_for_each_element(&interfaces, iface, avl) {
 346                 struct dhcp_assignment *a, *n;
 347
 348                 if (iface->dhcpv4 != MODE_SERVER)
 349                         continue;
 350
 351                 list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
 352                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
 353                                 free_assignment(a);
 354                 }
 355         }
 356         uloop_timeout_set(event, 1000);
 357 }
 358
 359 static void handle_addrlist_change(struct interface *iface)
 360 {
 361         struct odhcpd_ipaddr ip;
 362         struct odhcpd_ref_ip *a;
 363         struct dhcp_assignment *c;
 364         uint32_t mask = iface->dhcpv4_mask.s_addr;
 365
 366         memset(&ip, 0, sizeof(ip));
 367         ip.addr.in = iface->dhcpv4_local;
 368         ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
 369         ip.broadcast = iface->dhcpv4_bcast;
 370
 371         setup_dhcpv4_addresses(iface);
 372
 373         if ((ip.addr.in.s_addr & mask) ==
 374             (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
 375                 return;
 376
 377         if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
 378                 return;
 379
 380         if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
 381                 return;
 382
 383         a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
 384
 385         if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
 386                 syslog(LOG_WARNING, "Failed to add ip address on %s", iface->name);
 387                 return;
 388         }
 389
 390         list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 391                 if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
 392                         if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
 393                                 dhcpv4_fr_rand_delay(c);
 394                         else
 395                                 dhcpv4_fr_stop(c);
 396                 }
 397         }
 398 }
 399
 400 static char *dhcpv4_msg_to_string(uint8_t reqmsg)
 401 {
 402         switch (reqmsg) {
 403         case (DHCPV4_MSG_DISCOVER):
 404                 return "DHCPV4_MSG_DISCOVER";
 405         case (DHCPV4_MSG_OFFER):
 406                 return "DHCPV4_MSG_OFFER";
 407         case (DHCPV4_MSG_REQUEST):
 408                 return "DHCPV4_MSG_REQUEST";
 409         case (DHCPV4_MSG_DECLINE):
 410                 return "DHCPV4_MSG_DECLINE";
 411         case (DHCPV4_MSG_ACK):
 412                 return "DHCPV4_MSG_ACK";
 413         case (DHCPV4_MSG_NAK):
 414                 return "DHCPV4_MSG_NAK";
 415         case (DHCPV4_MSG_RELEASE):
 416                 return "DHCPV4_MSG_RELEASE";
 417         case (DHCPV4_MSG_INFORM):
 418                 return "DHCPV4_MSG_INFORM";
 419         case (DHCPV4_MSG_FORCERENEW):
 420                 return "DHCPV4_MSG_FORCERENEW";
 421         default:
 422                 return "UNKNOWN";
 423         }
 424 }
 425
 426 static void dhcpv4_free_assignment(struct dhcp_assignment *a)
 427 {
 428         if (a->fr_ip)
 429                 dhcpv4_fr_stop(a);
 430 }
 431
 432 static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 433                 uint8_t type, uint8_t len, const void *data)
 434 {
 435         uint8_t *c = *cookie;
 436         uint8_t *end = (uint8_t *)msg + sizeof(*msg);
 437         bool tag_only = type == DHCPV4_OPT_PAD || type == DHCPV4_OPT_END;
 438         int total_len = tag_only ? 1 : 2 + len;
 439
 440         if (*cookie + total_len > end)
 441                 return;
 442
 443         *cookie += total_len;
 444         *c++ = type;
 445
 446         if (tag_only)
 447                 return;
 448
 449         *c++ = len;
 450         memcpy(c, data, len);
 451 }
 452
 453 static void dhcpv4_fr_send(struct dhcp_assignment *a)
 454 {
 455         struct dhcpv4_message fr_msg = {
 456                 .op = DHCPV4_BOOTREPLY,
 457                 .htype = 1,
 458                 .hlen = 6,
 459                 .hops = 0,
 460                 .secs = 0,
 461                 .flags = 0,
 462                 .ciaddr = {INADDR_ANY},
 463                 .yiaddr = {INADDR_ANY},
 464                 .siaddr = {INADDR_ANY},
 465                 .giaddr = {INADDR_ANY},
 466                 .chaddr = {0},
 467                 .sname = {0},
 468                 .file = {0},
 469         };
 470         struct dhcpv4_auth_forcerenew *auth_o, auth = {
 471                 .protocol = 3,
 472                 .algorithm = 1,
 473                 .rdm = 0,
 474                 .replay = {htonl(time(NULL)), htonl(++serial)},
 475                 .type = 2,
 476                 .key = {0},
 477         };
 478         struct interface *iface = a->iface;
 479
 480         odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
 481         memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
 482
 483         fr_msg.options[0] = 0x63;
 484         fr_msg.options[1] = 0x82;
 485         fr_msg.options[2] = 0x53;
 486         fr_msg.options[3] = 0x63;
 487
 488         uint8_t *cookie = &fr_msg.options[4];
 489         uint8_t msg = DHCPV4_MSG_FORCERENEW;
 490
 491         dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 492         if (a->accept_fr_nonce) {
 493                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 494                 auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
 495                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 496
 497                 md5_ctx_t md5;
 498                 uint8_t secretbytes[64];
 499                 memset(secretbytes, 0, sizeof(secretbytes));
 500                 memcpy(secretbytes, a->key, sizeof(a->key));
 501
 502                 for (size_t i = 0; i < sizeof(secretbytes); ++i)
 503                         secretbytes[i] ^= 0x36;
 504
 505                 md5_begin(&md5);
 506                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 507                 md5_hash(&fr_msg, sizeof(fr_msg), &md5);
 508                 md5_end(auth_o->key, &md5);
 509
 510                 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 511                         secretbytes[i] ^= 0x36;
 512                         secretbytes[i] ^= 0x5c;
 513                 }
 514
 515                 md5_begin(&md5);
 516                 md5_hash(secretbytes, sizeof(secretbytes), &md5);
 517                 md5_hash(auth_o->key, sizeof(auth_o->key), &md5);
 518                 md5_end(auth_o->key, &md5);
 519         } else {
 520                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
 521                                 &a->fr_ip->addr.addr.in.s_addr);
 522                 dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
 523         }
 524
 525         struct sockaddr_in dest;
 526         memset(&dest, 0, sizeof(dest));
 527         dest.sin_family = AF_INET;
 528         dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 529         dest.sin_addr.s_addr = a->addr;
 530
 531         if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, PACKET_SIZE(&fr_msg, cookie),
 532                         MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
 533                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
 534                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 535         else
 536                 syslog(LOG_DEBUG, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
 537                         odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
 538 }
 539
 540 static void dhcpv4_fr_timer(struct uloop_timeout *event)
 541 {
 542         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 543
 544         if (a->fr_cnt > 0 && a->fr_cnt < 8) {
 545                 dhcpv4_fr_send(a);
 546                 uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 547                 a->fr_cnt++;
 548         } else
 549                 dhcpv4_fr_stop(a);
 550 }
 551
 552 static void dhcpv4_fr_start(struct dhcp_assignment *a)
 553 {
 554         uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
 555         a->fr_timer.cb = dhcpv4_fr_timer;
 556         a->fr_cnt++;
 557
 558         dhcpv4_fr_send(a);
 559 }
 560
 561 static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
 562 {
 563         struct dhcp_assignment *a = container_of(event, struct dhcp_assignment, fr_timer);
 564         struct interface *iface = a->iface;
 565
 566         (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
 567 }
 568
 569 static void dhcpv4_fr_rand_delay(struct dhcp_assignment *a)
 570 {
 571 #define MIN_DELAY   500
 572 #define MAX_FUZZ    500
 573         int msecs;
 574
 575         odhcpd_urandom(&msecs, sizeof(msecs));
 576
 577         msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
 578
 579         uloop_timeout_set(&a->fr_timer, msecs);
 580         a->fr_timer.cb = dhcpv4_fr_delay_timer;
 581 }
 582
 583 static void dhcpv4_fr_stop(struct dhcp_assignment *a)
 584 {
 585         uloop_timeout_cancel(&a->fr_timer);
 586         decr_ref_cnt_ip(&a->fr_ip, a->iface);
 587         a->fr_cnt = 0;
 588         a->fr_timer.cb = NULL;
 589 }
 590
 591 /* Handler for DHCPv4 messages */
 592 static void handle_dhcpv4(void *addr, void *data, size_t len,
 593                 struct interface *iface, _unused void *dest_addr)
 594 {
 595         struct dhcpv4_message *req = data;
 596
 597         if (iface->dhcpv4 == MODE_DISABLED)
 598                 return;
 599
 600         if (len < offsetof(struct dhcpv4_message, options) + 4 ||
 601                         req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
 602                 return;
 603
 604         syslog(LOG_DEBUG, "Got DHCPv4 request on %s", iface->name);
 605
 606         if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
 607                 syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
 608                 return;
 609         }
 610
 611         int sock = iface->dhcpv4_event.uloop.fd;
 612
 613         struct dhcpv4_message reply = {
 614                 .op = DHCPV4_BOOTREPLY,
 615                 .htype = req->htype,
 616                 .hlen = req->hlen,
 617                 .hops = 0,
 618                 .xid = req->xid,
 619                 .secs = 0,
 620                 .flags = req->flags,
 621                 .ciaddr = {INADDR_ANY},
 622                 .giaddr = req->giaddr,
 623                 .siaddr = iface->dhcpv4_local,
 624         };
 625         memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
 626
 627         reply.options[0] = 0x63;
 628         reply.options[1] = 0x82;
 629         reply.options[2] = 0x53;
 630         reply.options[3] = 0x63;
 631
 632         uint8_t *cookie = &reply.options[4];
 633         uint8_t reqmsg = DHCPV4_MSG_REQUEST;
 634         uint8_t msg = DHCPV4_MSG_ACK;
 635
 636         uint32_t reqaddr = INADDR_ANY;
 637         uint32_t leasetime = 0;
 638         size_t hostname_len = 0;
 639         size_t reqopts_len = 0;
 640         char hostname[256];
 641         char reqopts[256];
 642         bool accept_fr_nonce = false;
 643         bool incl_fr_opt = false;
 644
 645         uint8_t *start = &req->options[4];
 646         uint8_t *end = ((uint8_t*)data) + len;
 647         struct dhcpv4_option *opt;
 648         dhcpv4_for_each_option(start, end, opt) {
 649                 if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
 650                         reqmsg = opt->data[0];
 651                 else if (opt->type == DHCPV4_OPT_REQOPTS && opt->len > 0) {
 652                         reqopts_len = opt->len;
 653                         memcpy(reqopts, opt->data, reqopts_len);
 654                         reqopts[reqopts_len] = 0;
 655                 } else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
 656                         hostname_len = opt->len;
 657                         memcpy(hostname, opt->data, hostname_len);
 658                         hostname[hostname_len] = 0;
 659                 } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
 660                         memcpy(&reqaddr, opt->data, 4);
 661                 else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
 662                         if (memcmp(opt->data, &iface->dhcpv4_local, 4))
 663                                 return;
 664                 } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
 665                         uint8_t *c = opt->data, *cend = &opt->data[opt->len];
 666                         for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
 667                                 size_t elen = strlen(iface->filter_class);
 668                                 if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
 669                                         return; // Ignore from homenet
 670                         }
 671                 } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
 672                         memcpy(&leasetime, opt->data, 4);
 673                 else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
 674                         for (uint8_t i = 0; i < opt->len; i++) {
 675                                 if (opt->data[i] == 1) {
 676                                         accept_fr_nonce = true;
 677                                         break;
 678                                 }
 679                         }
 680
 681                 }
 682         }
 683
 684         if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
 685             reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
 686             reqmsg != DHCPV4_MSG_RELEASE)
 687                 return;
 688
 689         struct dhcp_assignment *a = NULL;
 690         uint32_t serverid = iface->dhcpv4_local.s_addr;
 691         uint32_t fr_serverid = INADDR_ANY;
 692
 693         if (reqmsg != DHCPV4_MSG_INFORM)
 694                 a = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
 695                                  &leasetime, hostname, hostname_len,
 696                                  accept_fr_nonce, &incl_fr_opt, &fr_serverid,
 697                                  reqopts, reqopts_len);
 698
 699         if (!a) {
 700                 if (reqmsg == DHCPV4_MSG_REQUEST)
 701                         msg = DHCPV4_MSG_NAK;
 702                 else if (reqmsg == DHCPV4_MSG_DISCOVER)
 703                         return;
 704         } else if (reqmsg == DHCPV4_MSG_DISCOVER)
 705                 msg = DHCPV4_MSG_OFFER;
 706         else if (reqmsg == DHCPV4_MSG_REQUEST &&
 707                         ((reqaddr && reqaddr != a->addr) ||
 708                          (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr))) {
 709                 msg = DHCPV4_MSG_NAK;
 710                 /*
 711                  * DHCP client requested an IP which we can't offer to him. Probably the
 712                  * client changed the network or the network has been changed. The reply
 713                  * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
 714                  *
 715                  * For modern devices we build an answer that includes a valid IP, like
 716                  * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
 717                  * perform additional DHCP round trips.
 718                  *
 719                  */
 720
 721                 /*
 722                  *
 723                  * Buggy clients do serverid checking in nack messages; therefore set the
 724                  * serverid in nack messages triggered by a previous force renew equal to
 725                  * the server id in use at that time by the server
 726                  *
 727                  */
 728                 if (fr_serverid)
 729                         serverid = fr_serverid;
 730
 731                 if (req->ciaddr.s_addr &&
 732                                 ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
 733                                  (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 734                         req->ciaddr.s_addr = INADDR_ANY;
 735         }
 736
 737         syslog(LOG_INFO, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
 738                         odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
 739
 740 #ifdef WITH_UBUS
 741         if (reqmsg == DHCPV4_MSG_RELEASE)
 742                 ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
 743                                         &req->ciaddr, hostname, iface->ifname);
 744 #endif
 745         if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
 746                 return;
 747
 748         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
 749         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
 750
 751         if (a) {
 752                 uint32_t val;
 753
 754                 reply.yiaddr.s_addr = a->addr;
 755
 756                 val = htonl(leasetime);
 757                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
 758
 759                 if (leasetime != UINT32_MAX) {
 760                         val = htonl(500 * leasetime / 1000);
 761                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
 762
 763                         val = htonl(875 * leasetime / 1000);
 764                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
 765                 }
 766
 767                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
 768                                 &iface->dhcpv4_mask.s_addr);
 769
 770                 if (a->hostname)
 771                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
 772                                         strlen(a->hostname), a->hostname);
 773
 774                 if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
 775                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
 776
 777                 if (incl_fr_opt) {
 778                         if (reqmsg == DHCPV4_MSG_REQUEST) {
 779                                 struct dhcpv4_auth_forcerenew auth = {
 780                                         .protocol = 3,
 781                                         .algorithm = 1,
 782                                         .rdm = 0,
 783                                         .replay = {htonl(time(NULL)), htonl(++serial)},
 784                                         .type = 1,
 785                                         .key = {0},
 786                                 };
 787
 788                                 memcpy(auth.key, a->key, sizeof(auth.key));
 789                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
 790                         } else {
 791                                 uint8_t one = 1;
 792                                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
 793                                         sizeof(one), &one);
 794                         }
 795                 }
 796         }
 797
 798         struct ifreq ifr;
 799
 800         memset(&ifr, 0, sizeof(ifr));
 801         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 802
 803         if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 804                 uint16_t mtu = htons(ifr.ifr_mtu);
 805                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
 806         }
 807
 808         if (iface->search && iface->search_len <= 255)
 809                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 810                                 iface->search_len, iface->search);
 811         else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 812                 uint8_t search_buf[256];
 813                 int len = dn_comp(_res.dnsrch[0], search_buf,
 814                                                 sizeof(search_buf), NULL, NULL);
 815                 if (len > 0)
 816                         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
 817                                         len, search_buf);
 818         }
 819
 820         if (iface->dhcpv4_router_cnt == 0)
 821                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
 822         else
 823                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
 824                                 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
 825
 826
 827         if (iface->dhcpv4_dns_cnt == 0)
 828                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
 829         else
 830                 dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
 831                                 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
 832
 833
 834         dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
 835
 836         struct sockaddr_in dest = *((struct sockaddr_in*)addr);
 837         if (req->giaddr.s_addr) {
 838                 /*
 839                  * relay agent is configured, send reply to the agent
 840                  */
 841                 dest.sin_addr = req->giaddr;
 842                 dest.sin_port = htons(DHCPV4_SERVER_PORT);
 843         } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
 844                 /*
 845                  * client has existing configuration (ciaddr is set) AND this address is
 846                  * not the address it used for the dhcp message
 847                  */
 848                 dest.sin_addr = req->ciaddr;
 849                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 850         } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
 851                         req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
 852                 /*
 853                  * client requests a broadcast reply OR we can't offer an IP
 854                  */
 855                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 856                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 857         } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
 858                 /*
 859                  * client has no previous configuration -> no IP, so we need to reply
 860                  * with a broadcast packet
 861                  */
 862                 dest.sin_addr.s_addr = INADDR_BROADCAST;
 863                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 864         } else {
 865                 struct arpreq arp = {.arp_flags = ATF_COM};
 866
 867                 /*
 868                  * send reply to the newly (in this proccess) allocated IP
 869                  */
 870                 dest.sin_addr = reply.yiaddr;
 871                 dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 872
 873                 memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
 874                 memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
 875                 memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
 876
 877                 if (ioctl(sock, SIOCSARP, &arp) < 0)
 878                         syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
 879         }
 880
 881         if (sendto(sock, &reply, PACKET_SIZE(&reply, cookie), MSG_DONTWAIT,
 882                         (struct sockaddr*)&dest, sizeof(dest)) < 0)
 883                 syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
 884                         dhcpv4_msg_to_string(msg),
 885                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 886                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 887                         inet_ntoa(dest.sin_addr));
 888         else
 889                 syslog(LOG_DEBUG, "Sent %s to %s - %s",
 890                         dhcpv4_msg_to_string(msg),
 891                         dest.sin_addr.s_addr == INADDR_BROADCAST ?
 892                         "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
 893                         inet_ntoa(dest.sin_addr));
 894
 895
 896 #ifdef WITH_UBUS
 897         if (msg == DHCPV4_MSG_ACK)
 898                 ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
 899                                         hostname, iface->ifname);
 900 #endif
 901 }
 902
 903 static bool dhcpv4_insert_assignment(struct list_head *list, struct dhcp_assignment *a,
 904                                      uint32_t addr)
 905 {
 906         uint32_t h_addr = ntohl(addr);
 907         struct dhcp_assignment *c;
 908
 909         list_for_each_entry(c, list, head) {
 910                 uint32_t c_addr = ntohl(c->addr);
 911
 912                 if (c_addr == h_addr)
 913                         return false;
 914
 915                 if (c_addr > h_addr)
 916                         break;
 917         }
 918
 919         /* Insert new node before c (might match list head) */
 920         a->addr = addr;
 921         list_add_tail(&a->head, &c->head);
 922
 923         return true;
 924 }
 925
 926 static char* ip4toa(uint32_t addr)
 927 {
 928         static char buf[16];
 929
 930         snprintf(buf, sizeof(buf), "%u.%u.%u.%u",
 931                 ((uint8_t *)&addr)[0], ((uint8_t *)&addr)[1],
 932                 ((uint8_t *)&addr)[2], ((uint8_t *)&addr)[3]);
 933
 934         return buf;
 935 }
 936
 937 static bool dhcpv4_assign(struct interface *iface, struct dhcp_assignment *a,
 938                           uint32_t raddr)
 939 {
 940         uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
 941         uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
 942         uint32_t count = end - start + 1;
 943         uint32_t seed = 0;
 944         bool assigned;
 945
 946         /* Preconfigured IP address by static lease */
 947         if (a->addr) {
 948                 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
 949                                                     a, a->addr);
 950
 951                 if (assigned)
 952                         syslog(LOG_DEBUG, "Assigning static IP: %s", ip4toa(a->addr));
 953
 954                 return assigned;
 955         }
 956
 957         /* try to assign the IP the client asked for */
 958         if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
 959             !config_find_lease_by_ipaddr(raddr)) {
 960                 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
 961                                                     a, raddr);
 962
 963                 if (assigned) {
 964                         syslog(LOG_DEBUG, "Assigning the IP the client asked for: %s",
 965                                ip4toa(a->addr));
 966
 967                         return true;
 968                 }
 969         }
 970
 971         /* Seed RNG with checksum of hwaddress */
 972         for (size_t i = 0; i < sizeof(a->hwaddr); ++i) {
 973                 /* Knuth's multiplicative method */
 974                 uint8_t o = a->hwaddr[i];
 975                 seed += (o*2654435761) % UINT32_MAX;
 976         }
 977
 978         srand(seed);
 979
 980         for (uint32_t i = 0, try = (((uint32_t)rand()) % count) + start; i < count;
 981              ++i, try = (((try - start) + 1) % count) + start) {
 982                 uint32_t n_try = htonl(try);
 983
 984                 if (config_find_lease_by_ipaddr(n_try))
 985                         continue;
 986
 987                 assigned = dhcpv4_insert_assignment(&iface->dhcpv4_assignments,
 988                                                     a, n_try);
 989
 990                 if (assigned) {
 991                         syslog(LOG_DEBUG, "Assigning mapped IP: %s (try %u of %u)",
 992                                ip4toa(a->addr), i + 1, count);
 993
 994                         return true;
 995                 }
 996         }
 997
 998         syslog(LOG_NOTICE, "Can't assign any IP address -> address space is full");
 999
1000         return false;
1001 }
1002
1003
1004 static struct dhcp_assignment*
1005 dhcpv4_lease(struct interface *iface, enum dhcpv4_msg msg, const uint8_t *mac,
1006              const uint32_t reqaddr, uint32_t *leasetime, const char *hostname,
1007              const size_t hostname_len, const bool accept_fr_nonce, bool *incl_fr_opt,
1008              uint32_t *fr_serverid, const char* reqopts, const size_t reqopts_len)
1009 {
1010         struct dhcp_assignment *a = find_assignment_by_hwaddr(iface, mac);
1011         struct lease *l = config_find_lease_by_mac(mac);
1012         time_t now = odhcpd_time();
1013
1014         if (l && a && a->lease != l) {
1015                 free_assignment(a);
1016                 a = NULL;
1017         }
1018
1019         if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
1020                 *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
1021                 dhcpv4_fr_stop(a);
1022         }
1023
1024         if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
1025                 bool assigned = !!a;
1026
1027                 if (!a) {
1028                         if (!iface->no_dynamic_dhcp || l) {
1029                                 /* Create new binding */
1030                                 a = alloc_assignment(0);
1031                                 if (!a) {
1032                                         syslog(LOG_WARNING, "Failed to alloc assignment on interface %s",
1033                                                             iface->ifname);
1034                                         return NULL;
1035                                 }
1036                                 memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
1037                                 /* Set valid time to 0 for static lease indicating */
1038                                 /* infinite lifetime otherwise current time        */
1039                                 a->valid_until = l ? 0 : now;
1040                                 a->dhcp_free_cb = dhcpv4_free_assignment;
1041                                 a->iface = iface;
1042                                 a->flags = OAF_DHCPV4;
1043                                 a->addr = l ? l->ipaddr : INADDR_ANY;
1044
1045                                 assigned = dhcpv4_assign(iface, a, reqaddr);
1046
1047                                 if (l) {
1048                                         a->flags |= OAF_STATIC;
1049
1050                                         if (l->hostname)
1051                                                 a->hostname = strdup(l->hostname);
1052
1053                                         if (l->leasetime)
1054                                                 a->leasetime = l->leasetime;
1055
1056                                         list_add(&a->lease_list, &l->assignments);
1057                                         a->lease = l;
1058                                 }
1059                         }
1060                 } else if (((a->addr & iface->dhcpv4_mask.s_addr) !=
1061                             (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) &&
1062                             !(a->flags & OAF_STATIC)) {
1063                         list_del_init(&a->head);
1064                         a->addr = INADDR_ANY;
1065
1066                         assigned = dhcpv4_assign(iface, a, reqaddr);
1067                 }
1068
1069                 if (assigned) {
1070                         uint32_t my_leasetime;
1071
1072                         if (a->leasetime)
1073                                 my_leasetime = a->leasetime;
1074                         else
1075                                 my_leasetime = iface->dhcpv4_leasetime;
1076
1077                         if ((*leasetime == 0) || (my_leasetime < *leasetime))
1078                                 *leasetime = my_leasetime;
1079
1080                         if (msg == DHCPV4_MSG_DISCOVER) {
1081                                 a->flags &= ~OAF_BOUND;
1082
1083                                 *incl_fr_opt = accept_fr_nonce;
1084                                 if (!(a->flags & OAF_STATIC))
1085                                         a->valid_until = now;
1086                         } else {
1087                                 if ((!(a->flags & OAF_STATIC) || !a->hostname) && hostname_len > 0) {
1088                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1089                                         if (a->hostname) {
1090                                                 memcpy(a->hostname, hostname, hostname_len);
1091                                                 a->hostname[hostname_len] = 0;
1092
1093                                                 if (odhcpd_valid_hostname(a->hostname))
1094                                                         a->flags &= ~OAF_BROKEN_HOSTNAME;
1095                                                 else
1096                                                         a->flags |= OAF_BROKEN_HOSTNAME;
1097                                         }
1098                                 }
1099
1100                                 if (reqopts_len > 0) {
1101                                         a->reqopts = realloc(a->reqopts, reqopts_len + 1);
1102                                         if (a->reqopts) {
1103                                                 memcpy(a->reqopts, reqopts, reqopts_len);
1104                                                 a->reqopts[reqopts_len] = 0;
1105                                         }
1106                                 }
1107
1108                                 if (!(a->flags & OAF_BOUND)) {
1109                                         a->accept_fr_nonce = accept_fr_nonce;
1110                                         *incl_fr_opt = accept_fr_nonce;
1111                                         odhcpd_urandom(a->key, sizeof(a->key));
1112                                         a->flags |= OAF_BOUND;
1113                                 } else
1114                                         *incl_fr_opt = false;
1115
1116                                 if (!(a->flags & OAF_STATIC))
1117                                         a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
1118                         }
1119                 } else if (!assigned && a) {
1120                         /* Cleanup failed assignment */
1121                         free_assignment(a);
1122                         a = NULL;
1123                 }
1124
1125         } else if (msg == DHCPV4_MSG_RELEASE && a) {
1126                 a->flags &= ~OAF_BOUND;
1127
1128                 if (!(a->flags & OAF_STATIC))
1129                         a->valid_until = now - 1;
1130
1131         } else if (msg == DHCPV4_MSG_DECLINE && a) {
1132                 a->flags &= ~OAF_BOUND;
1133
1134                 if (!(a->flags & OAF_STATIC)) {
1135                         memset(a->hwaddr, 0, sizeof(a->hwaddr));
1136                         a->valid_until = now + 3600; /* Block address for 1h */
1137                 }
1138         }
1139
1140         dhcpv6_ia_write_statefile();
1141
1142         return a;
1143 }