src/libsystemd-dhcp/sd-dhcp-client.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2013 Intel Corporation. All rights reserved.
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdlib.h>
  21 #include <errno.h>
  22 #include <string.h>
  23 #include <stdio.h>
  24 #include <net/ethernet.h>
  25 #include <sys/param.h>
  26
  27 #include "util.h"
  28 #include "list.h"
  29
  30 #include "dhcp-protocol.h"
  31 #include "dhcp-lease.h"
  32 #include "dhcp-internal.h"
  33 #include "sd-dhcp-client.h"
  34
  35 struct sd_dhcp_client {
  36         DHCPState state;
  37         sd_event *event;
  38         int event_priority;
  39         sd_event_source *timeout_resend;
  40         int index;
  41         int fd;
  42         union sockaddr_union link;
  43         sd_event_source *receive_message;
  44         uint8_t *req_opts;
  45         size_t req_opts_allocated;
  46         size_t req_opts_size;
  47         be32_t last_addr;
  48         struct ether_addr mac_addr;
  49         uint32_t xid;
  50         usec_t start_time;
  51         uint16_t secs;
  52         unsigned int attempt;
  53         usec_t request_sent;
  54         sd_event_source *timeout_t1;
  55         sd_event_source *timeout_t2;
  56         sd_event_source *timeout_expire;
  57         sd_dhcp_client_cb_t cb;
  58         void *userdata;
  59         sd_dhcp_lease *lease;
  60 };
  61
  62 static const uint8_t default_req_opts[] = {
  63         DHCP_OPTION_SUBNET_MASK,
  64         DHCP_OPTION_ROUTER,
  65         DHCP_OPTION_HOST_NAME,
  66         DHCP_OPTION_DOMAIN_NAME,
  67         DHCP_OPTION_DOMAIN_NAME_SERVER,
  68         DHCP_OPTION_NTP_SERVER,
  69 };
  70
  71 static int client_receive_message_raw(sd_event_source *s, int fd,
  72                                       uint32_t revents, void *userdata);
  73 static int client_receive_message_udp(sd_event_source *s, int fd,
  74                                       uint32_t revents, void *userdata);
  75
  76 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
  77                                 void *userdata) {
  78         assert_return(client, -EINVAL);
  79
  80         client->cb = cb;
  81         client->userdata = userdata;
  82
  83         return 0;
  84 }
  85
  86 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
  87         size_t i;
  88
  89         assert_return(client, -EINVAL);
  90         assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
  91
  92         switch(option) {
  93         case DHCP_OPTION_PAD:
  94         case DHCP_OPTION_OVERLOAD:
  95         case DHCP_OPTION_MESSAGE_TYPE:
  96         case DHCP_OPTION_PARAMETER_REQUEST_LIST:
  97         case DHCP_OPTION_END:
  98                 return -EINVAL;
  99
 100         default:
 101                 break;
 102         }
 103
 104         for (i = 0; i < client->req_opts_size; i++)
 105                 if (client->req_opts[i] == option)
 106                         return -EEXIST;
 107
 108         if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
 109                             client->req_opts_size + 1))
 110                 return -ENOMEM;
 111
 112         client->req_opts[client->req_opts_size++] = option;
 113
 114         return 0;
 115 }
 116
 117 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
 118                                        const struct in_addr *last_addr) {
 119         assert_return(client, -EINVAL);
 120         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 121
 122         if (last_addr)
 123                 client->last_addr = last_addr->s_addr;
 124         else
 125                 client->last_addr = INADDR_ANY;
 126
 127         return 0;
 128 }
 129
 130 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
 131         assert_return(client, -EINVAL);
 132         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 133         assert_return(interface_index >= -1, -EINVAL);
 134
 135         client->index = interface_index;
 136
 137         return 0;
 138 }
 139
 140 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
 141                            const struct ether_addr *addr) {
 142         assert_return(client, -EINVAL);
 143         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 144
 145         memcpy(&client->mac_addr, addr, ETH_ALEN);
 146
 147         return 0;
 148 }
 149
 150 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
 151         assert_return(client, -EINVAL);
 152         assert_return(ret, -EINVAL);
 153
 154         if (client->state != DHCP_STATE_BOUND &&
 155             client->state != DHCP_STATE_RENEWING &&
 156             client->state != DHCP_STATE_REBINDING)
 157                 return -EADDRNOTAVAIL;
 158
 159         *ret = sd_dhcp_lease_ref(client->lease);
 160
 161         return 0;
 162 }
 163
 164 static int client_notify(sd_dhcp_client *client, int event) {
 165         if (client->cb)
 166                 client->cb(client, event, client->userdata);
 167
 168         return 0;
 169 }
 170
 171 static int client_stop(sd_dhcp_client *client, int error) {
 172         assert_return(client, -EINVAL);
 173
 174         client->receive_message =
 175                 sd_event_source_unref(client->receive_message);
 176
 177         if (client->fd >= 0)
 178                 close(client->fd);
 179         client->fd = -1;
 180
 181         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 182
 183         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 184         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 185         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 186
 187         client->attempt = 1;
 188
 189         client_notify(client, error);
 190
 191         client->start_time = 0;
 192         client->secs = 0;
 193         client->state = DHCP_STATE_INIT;
 194
 195         if (client->lease)
 196                 client->lease = sd_dhcp_lease_unref(client->lease);
 197
 198         return 0;
 199 }
 200
 201 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
 202                                uint8_t type, uint16_t secs, uint8_t **opt,
 203                                size_t *optlen) {
 204         int r;
 205
 206         r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
 207                               secs, opt, optlen);
 208         if (r < 0)
 209                 return r;
 210
 211         memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
 212
 213         if (client->state == DHCP_STATE_RENEWING ||
 214             client->state == DHCP_STATE_REBINDING)
 215                 message->ciaddr = client->lease->address;
 216
 217         /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
 218            Identifier option is not set */
 219         r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
 220                                ETH_ALEN, &client->mac_addr);
 221         if (r < 0)
 222                 return r;
 223
 224         if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
 225                 be16_t max_size;
 226
 227                 r = dhcp_option_append(opt, optlen,
 228                                        DHCP_OPTION_PARAMETER_REQUEST_LIST,
 229                                        client->req_opts_size,
 230                                        client->req_opts);
 231                 if (r < 0)
 232                         return r;
 233
 234                 /* Some DHCP servers will send bigger DHCP packets than the
 235                    defined default size unless the Maximum Messge Size option
 236                    is explicitely set */
 237                 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
 238                                    DHCP_MIN_OPTIONS_SIZE);
 239                 r = dhcp_option_append(opt, optlen,
 240                                        DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
 241                                        2, &max_size);
 242                 if (r < 0)
 243                         return r;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
 250         int err = 0;
 251         _cleanup_free_ DHCPPacket *discover;
 252         size_t optlen, len;
 253         uint8_t *opt;
 254
 255         optlen = DHCP_MIN_OPTIONS_SIZE;
 256         len = sizeof(DHCPPacket) + optlen;
 257
 258         discover = malloc0(len);
 259
 260         if (!discover)
 261                 return -ENOMEM;
 262
 263         err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
 264                                   secs, &opt, &optlen);
 265         if (err < 0)
 266                 return err;
 267
 268         if (client->last_addr != INADDR_ANY) {
 269                 err = dhcp_option_append(&opt, &optlen,
 270                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 271                                          4, &client->last_addr);
 272                 if (err < 0)
 273                         return err;
 274         }
 275
 276         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 277         if (err < 0)
 278                 return err;
 279
 280         dhcp_packet_append_ip_headers(discover, BOOTREQUEST, len);
 281
 282         err = dhcp_network_send_raw_socket(client->fd, &client->link,
 283                                            discover, len);
 284
 285         return err;
 286 }
 287
 288 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
 289         _cleanup_free_ DHCPPacket *request;
 290         size_t optlen, len;
 291         int err;
 292         uint8_t *opt;
 293
 294         optlen = DHCP_MIN_OPTIONS_SIZE;
 295         len = DHCP_MESSAGE_SIZE + optlen;
 296
 297         request = malloc0(len);
 298         if (!request)
 299                 return -ENOMEM;
 300
 301         err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
 302                                   &opt, &optlen);
 303         if (err < 0)
 304                 return err;
 305
 306         if (client->state == DHCP_STATE_REQUESTING) {
 307                 err = dhcp_option_append(&opt, &optlen,
 308                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 309                                          4, &client->lease->address);
 310                 if (err < 0)
 311                         return err;
 312
 313                 err = dhcp_option_append(&opt, &optlen,
 314                                          DHCP_OPTION_SERVER_IDENTIFIER,
 315                                          4, &client->lease->server_address);
 316                 if (err < 0)
 317                         return err;
 318         }
 319
 320         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 321         if (err < 0)
 322                 return err;
 323
 324         if (client->state == DHCP_STATE_RENEWING) {
 325                 err = dhcp_network_send_udp_socket(client->fd,
 326                                                    client->lease->server_address,
 327                                                    DHCP_PORT_SERVER,
 328                                                    &request->dhcp,
 329                                                    len - DHCP_IP_UDP_SIZE);
 330         } else {
 331                 dhcp_packet_append_ip_headers(request, BOOTREQUEST, len);
 332
 333                 err = dhcp_network_send_raw_socket(client->fd, &client->link,
 334                                                    request, len);
 335         }
 336
 337         return err;
 338 }
 339
 340 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 341 {
 342         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 343
 344         return client->secs;
 345 }
 346
 347 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 348                                  void *userdata) {
 349         sd_dhcp_client *client = userdata;
 350         usec_t next_timeout = 0;
 351         uint32_t time_left;
 352         int r = 0;
 353
 354         assert(s);
 355         assert(client);
 356         assert(client->event);
 357
 358         switch (client->state) {
 359         case DHCP_STATE_RENEWING:
 360
 361                 time_left = (client->lease->t2 - client->lease->t1) / 2;
 362                 if (time_left < 60)
 363                         time_left = 60;
 364
 365                 next_timeout = usec + time_left * USEC_PER_SEC;
 366
 367                 break;
 368
 369         case DHCP_STATE_REBINDING:
 370
 371                 time_left = (client->lease->lifetime - client->lease->t2) / 2;
 372                 if (time_left < 60)
 373                         time_left = 60;
 374
 375                 next_timeout = usec + time_left * USEC_PER_SEC;
 376                 break;
 377
 378         case DHCP_STATE_INIT:
 379         case DHCP_STATE_INIT_REBOOT:
 380         case DHCP_STATE_REBOOTING:
 381         case DHCP_STATE_SELECTING:
 382         case DHCP_STATE_REQUESTING:
 383         case DHCP_STATE_BOUND:
 384
 385                 if (client->attempt < 64)
 386                         client->attempt *= 2;
 387
 388                 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
 389
 390                 break;
 391         }
 392
 393         next_timeout += (random_u32() & 0x1fffff);
 394
 395         r = sd_event_add_monotonic(client->event,
 396                                      &client->timeout_resend,
 397                                      next_timeout,
 398                                      10 * USEC_PER_MSEC,
 399                                      client_timeout_resend, client);
 400         if (r < 0)
 401                 goto error;
 402
 403         r = sd_event_source_set_priority(client->timeout_resend,
 404                                          client->event_priority);
 405         if (r < 0)
 406                 goto error;
 407
 408         switch (client->state) {
 409         case DHCP_STATE_INIT:
 410
 411                 client_update_secs(client, usec);
 412
 413                 r = client_send_discover(client, client->secs);
 414                 if (r >= 0) {
 415                         client->state = DHCP_STATE_SELECTING;
 416                         client->attempt = 1;
 417                 } else {
 418                         if (client->attempt >= 64)
 419                                 goto error;
 420                 }
 421
 422                 break;
 423
 424         case DHCP_STATE_SELECTING:
 425                 client_update_secs(client, usec);
 426
 427                 r = client_send_discover(client, client->secs);
 428                 if (r < 0 && client->attempt >= 64)
 429                         goto error;
 430
 431                 break;
 432
 433         case DHCP_STATE_REQUESTING:
 434         case DHCP_STATE_RENEWING:
 435         case DHCP_STATE_REBINDING:
 436                 r = client_send_request(client, client->secs);
 437                 if (r < 0 && client->attempt >= 64)
 438                          goto error;
 439
 440                 client->request_sent = usec;
 441
 442                 break;
 443
 444         case DHCP_STATE_INIT_REBOOT:
 445         case DHCP_STATE_REBOOTING:
 446         case DHCP_STATE_BOUND:
 447
 448                 break;
 449         }
 450
 451         return 0;
 452
 453 error:
 454         client_stop(client, r);
 455
 456         /* Errors were dealt with when stopping the client, don't spill
 457            errors into the event loop handler */
 458         return 0;
 459 }
 460
 461 static int client_initialize_events(sd_dhcp_client *client,
 462                                     sd_event_io_handler_t io_callback,
 463                                     usec_t usec) {
 464         int r;
 465
 466         assert(client);
 467         assert(client->event);
 468
 469         r = sd_event_add_io(client->event, &client->receive_message,
 470                             client->fd, EPOLLIN, io_callback,
 471                             client);
 472         if (r < 0)
 473                 goto error;
 474
 475         r = sd_event_source_set_priority(client->receive_message,
 476                                          client->event_priority);
 477         if (r < 0)
 478                 goto error;
 479
 480         r = sd_event_add_monotonic(client->event,
 481                                    &client->timeout_resend,
 482                                    usec, 0,
 483                                    client_timeout_resend, client);
 484         if (r < 0)
 485                 goto error;
 486
 487         r = sd_event_source_set_priority(client->timeout_resend,
 488                                          client->event_priority);
 489
 490 error:
 491         if (r < 0)
 492                 client_stop(client, r);
 493
 494         return 0;
 495
 496 }
 497
 498 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 499                                  void *userdata) {
 500         sd_dhcp_client *client = userdata;
 501
 502         client_stop(client, DHCP_EVENT_EXPIRED);
 503
 504         return 0;
 505 }
 506
 507 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 508         sd_dhcp_client *client = userdata;
 509         int r;
 510
 511         if (client->fd >= 0) {
 512                 client->receive_message =
 513                         sd_event_source_unref(client->receive_message);
 514                 close(client->fd);
 515                 client->fd = -1;
 516         }
 517
 518         client->state = DHCP_STATE_REBINDING;
 519         client->attempt = 1;
 520
 521         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 522         if (r < 0) {
 523                 client_stop(client, r);
 524                 return 0;
 525         }
 526
 527         client->fd = r;
 528
 529         return client_initialize_events(client, client_receive_message_raw,
 530                                         usec);
 531 }
 532
 533 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 534                              void *userdata) {
 535         sd_dhcp_client *client = userdata;
 536         int r;
 537
 538         client->state = DHCP_STATE_RENEWING;
 539         client->attempt = 1;
 540
 541         r = dhcp_network_bind_udp_socket(client->index,
 542                                          client->lease->address,
 543                                          DHCP_PORT_CLIENT);
 544         if (r < 0) {
 545                 client_stop(client, r);
 546                 return 0;
 547         }
 548
 549         client->fd = r;
 550
 551         return client_initialize_events(client, client_receive_message_udp, usec);
 552 }
 553
 554 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 555                                size_t len) {
 556         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 557         int r;
 558
 559         r = dhcp_lease_new(&lease);
 560         if (r < 0)
 561                 return r;
 562
 563         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 564         if (r != DHCP_OFFER)
 565                 return -ENOMSG;
 566
 567         lease->address = offer->yiaddr;
 568
 569         if (lease->address == INADDR_ANY ||
 570             lease->server_address == INADDR_ANY ||
 571             lease->subnet_mask == INADDR_ANY ||
 572             lease->lifetime == 0)
 573                 return -ENOMSG;
 574
 575         client->lease = lease;
 576         lease = NULL;
 577
 578         return 0;
 579 }
 580
 581 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 582                              size_t len) {
 583         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 584         int r;
 585
 586         r = dhcp_lease_new(&lease);
 587         if (r < 0)
 588                 return r;
 589
 590         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 591         if (r == DHCP_NAK)
 592                 return DHCP_EVENT_NO_LEASE;
 593
 594         if (r != DHCP_ACK)
 595                 return -ENOMSG;
 596
 597         lease->address = ack->yiaddr;
 598
 599         if (lease->address == INADDR_ANY ||
 600             lease->server_address == INADDR_ANY ||
 601             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 602                 return -ENOMSG;
 603
 604         r = DHCP_EVENT_IP_ACQUIRE;
 605         if (client->lease) {
 606                 if (client->lease->address != lease->address ||
 607                     client->lease->subnet_mask != lease->subnet_mask ||
 608                     client->lease->router != lease->router) {
 609                         r = DHCP_EVENT_IP_CHANGE;
 610                 }
 611
 612                 client->lease = sd_dhcp_lease_unref(client->lease);
 613         }
 614
 615         client->lease = lease;
 616         lease = NULL;
 617
 618         return r;
 619 }
 620
 621 static uint64_t client_compute_timeout(uint64_t request_sent,
 622                                        uint32_t lifetime) {
 623         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 624                 + (random_u32() & 0x1fffff);
 625 }
 626
 627 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 628         uint64_t next_timeout;
 629         int r;
 630
 631         assert(client);
 632         assert(client->event);
 633
 634         if (client->lease->lifetime < 10)
 635                 return -EINVAL;
 636
 637         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 638         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 639         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 640
 641         if (!client->lease->t1)
 642                 client->lease->t1 = client->lease->lifetime / 2;
 643
 644         next_timeout = client_compute_timeout(client->request_sent,
 645                                               client->lease->t1);
 646         if (next_timeout < usec)
 647                 return -EINVAL;
 648
 649         r = sd_event_add_monotonic(client->event,
 650                                      &client->timeout_t1,
 651                                      next_timeout,
 652                                      10 * USEC_PER_MSEC,
 653                                      client_timeout_t1, client);
 654         if (r < 0)
 655                 return r;
 656
 657         r = sd_event_source_set_priority(client->timeout_t1,
 658                                          client->event_priority);
 659         if (r < 0)
 660                 return r;
 661
 662         if (!client->lease->t2)
 663                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 664
 665         if (client->lease->t2 < client->lease->t1)
 666                 return -EINVAL;
 667
 668         if (client->lease->lifetime < client->lease->t2)
 669                 return -EINVAL;
 670
 671         next_timeout = client_compute_timeout(client->request_sent,
 672                                               client->lease->t2);
 673         if (next_timeout < usec)
 674                 return -EINVAL;
 675
 676         r = sd_event_add_monotonic(client->event,
 677                                      &client->timeout_t2,
 678                                      next_timeout,
 679                                      10 * USEC_PER_MSEC,
 680                                      client_timeout_t2, client);
 681         if (r < 0)
 682                 return r;
 683
 684         r = sd_event_source_set_priority(client->timeout_t2,
 685                                          client->event_priority);
 686         if (r < 0)
 687                 return r;
 688
 689         next_timeout = client_compute_timeout(client->request_sent,
 690                                               client->lease->lifetime);
 691         if (next_timeout < usec)
 692                 return -EINVAL;
 693
 694         r = sd_event_add_monotonic(client->event,
 695                                      &client->timeout_expire, next_timeout,
 696                                      10 * USEC_PER_MSEC,
 697                                      client_timeout_expire, client);
 698         if (r < 0)
 699                 return r;
 700
 701         r = sd_event_source_set_priority(client->timeout_expire,
 702                                          client->event_priority);
 703         if (r < 0)
 704                 return r;
 705
 706         return 0;
 707 }
 708
 709 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 710                                  int len, usec_t time_now) {
 711         int r = 0, notify_event = 0;
 712
 713         assert(client);
 714         assert(client->event);
 715         assert(message);
 716
 717         if (be32toh(message->xid) != client->xid)
 718                 return 0;
 719
 720         if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
 721                    ETHER_ADDR_LEN))
 722                 return 0;
 723
 724         switch (client->state) {
 725         case DHCP_STATE_SELECTING:
 726
 727                 r = client_handle_offer(client, message, len);
 728                 if (r >= 0) {
 729
 730                         client->timeout_resend =
 731                                 sd_event_source_unref(client->timeout_resend);
 732
 733                         client->state = DHCP_STATE_REQUESTING;
 734                         client->attempt = 1;
 735
 736                         r = sd_event_add_monotonic(client->event,
 737                                                    &client->timeout_resend,
 738                                                    time_now, 0,
 739                                                    client_timeout_resend,
 740                                                    client);
 741                         if (r < 0)
 742                                 goto error;
 743
 744                         r = sd_event_source_set_priority(client->timeout_resend,
 745                                                          client->event_priority);
 746                         if (r < 0)
 747                                 goto error;
 748                 }
 749
 750                 break;
 751
 752         case DHCP_STATE_REQUESTING:
 753         case DHCP_STATE_RENEWING:
 754         case DHCP_STATE_REBINDING:
 755
 756                 r = client_handle_ack(client, message, len);
 757
 758                 if (r == DHCP_EVENT_NO_LEASE)
 759                         goto error;
 760
 761                 if (r >= 0) {
 762                         client->timeout_resend =
 763                                 sd_event_source_unref(client->timeout_resend);
 764
 765                         if (client->state == DHCP_STATE_REQUESTING)
 766                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 767                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 768                                 notify_event = r;
 769
 770                         client->state = DHCP_STATE_BOUND;
 771                         client->attempt = 1;
 772
 773                         client->last_addr = client->lease->address;
 774
 775                         r = client_set_lease_timeouts(client, time_now);
 776                         if (r < 0)
 777                                 goto error;
 778
 779                         if (notify_event)
 780                                 client_notify(client, notify_event);
 781
 782                         client->receive_message =
 783                                 sd_event_source_unref(client->receive_message);
 784                         close(client->fd);
 785                         client->fd = -1;
 786                 }
 787
 788                 r = 0;
 789
 790                 break;
 791
 792         case DHCP_STATE_INIT:
 793         case DHCP_STATE_INIT_REBOOT:
 794         case DHCP_STATE_REBOOTING:
 795         case DHCP_STATE_BOUND:
 796
 797                 break;
 798         }
 799
 800 error:
 801         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 802                 return client_stop(client, r);
 803
 804         return 0;
 805 }
 806
 807 static int client_receive_message_udp(sd_event_source *s, int fd,
 808                                       uint32_t revents, void *userdata) {
 809         sd_dhcp_client *client = userdata;
 810         uint8_t buf[sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE];
 811         int buflen = sizeof(buf);
 812         int len, r = 0;
 813         usec_t time_now;
 814
 815         assert(s);
 816         assert(client);
 817         assert(client->event);
 818
 819         len = read(fd, &buf, buflen);
 820         if (len < 0)
 821                 return 0;
 822
 823         r = sd_event_get_now_monotonic(client->event, &time_now);
 824         if (r < 0)
 825                 return client_stop(client, r);
 826
 827         return client_handle_message(client, (DHCPMessage *) buf, len,
 828                                      time_now);
 829 }
 830
 831 static int client_receive_message_raw(sd_event_source *s, int fd,
 832                                       uint32_t revents, void *userdata) {
 833         sd_dhcp_client *client = userdata;
 834         uint8_t buf[sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE];
 835         int buflen = sizeof(buf);
 836         int len, r = 0;
 837         DHCPPacket *packet;
 838         usec_t time_now;
 839
 840         assert(s);
 841         assert(client);
 842         assert(client->event);
 843
 844         len = read(fd, &buf, buflen);
 845         if (len < 0)
 846                 return 0;
 847
 848         packet = (DHCPPacket *) buf;
 849
 850         r = dhcp_packet_verify_headers(packet, BOOTREPLY, len);
 851         if (r < 0)
 852                 return 0;
 853
 854         len -= DHCP_IP_UDP_SIZE;
 855
 856         r = sd_event_get_now_monotonic(client->event, &time_now);
 857         if (r < 0)
 858                 return client_stop(client, r);
 859
 860         return client_handle_message(client, &packet->dhcp, len, time_now);
 861 }
 862
 863 int sd_dhcp_client_start(sd_dhcp_client *client) {
 864         int r;
 865
 866         assert_return(client, -EINVAL);
 867         assert_return(client->event, -EINVAL);
 868         assert_return(client->index > 0, -EINVAL);
 869         assert_return(client->state == DHCP_STATE_INIT ||
 870                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 871
 872         client->xid = random_u32();
 873
 874         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 875
 876         if (r < 0) {
 877                 client_stop(client, r);
 878                 return r;
 879         }
 880
 881         client->fd = r;
 882         client->start_time = now(CLOCK_MONOTONIC);
 883         client->secs = 0;
 884
 885         return client_initialize_events(client, client_receive_message_raw,
 886                                         client->start_time);
 887 }
 888
 889 int sd_dhcp_client_stop(sd_dhcp_client *client) {
 890         return client_stop(client, DHCP_EVENT_STOP);
 891 }
 892
 893 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
 894                                 int priority) {
 895         int r;
 896
 897         assert_return(client, -EINVAL);
 898         assert_return(!client->event, -EBUSY);
 899
 900         if (event)
 901                 client->event = sd_event_ref(event);
 902         else {
 903                 r = sd_event_default(&client->event);
 904                 if (r < 0)
 905                         return 0;
 906         }
 907
 908         client->event_priority = priority;
 909
 910         return 0;
 911 }
 912
 913 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
 914         assert_return(client, -EINVAL);
 915
 916         client->event = sd_event_unref(client->event);
 917
 918         return 0;
 919 }
 920
 921 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
 922         if (!client)
 923                 return NULL;
 924
 925         return client->event;
 926 }
 927
 928 void sd_dhcp_client_free(sd_dhcp_client *client) {
 929         if (!client)
 930                 return;
 931
 932         sd_dhcp_client_stop(client);
 933         sd_dhcp_client_detach_event(client);
 934
 935         free(client->req_opts);
 936         free(client);
 937 }
 938
 939 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
 940 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
 941
 942 int sd_dhcp_client_new(sd_dhcp_client **ret) {
 943         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
 944
 945         assert_return(ret, -EINVAL);
 946
 947         client = new0(sd_dhcp_client, 1);
 948         if (!client)
 949                 return -ENOMEM;
 950
 951         client->state = DHCP_STATE_INIT;
 952         client->index = -1;
 953         client->fd = -1;
 954         client->attempt = 1;
 955
 956         client->req_opts_size = ELEMENTSOF(default_req_opts);
 957
 958         client->req_opts = memdup(default_req_opts, client->req_opts_size);
 959         if (!client->req_opts)
 960                 return -ENOMEM;
 961
 962         *ret = client;
 963         client = NULL;
 964
 965         return 0;
 966 }