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 #define DHCP_CLIENT_MIN_OPTIONS_SIZE            312
  36
  37 struct sd_dhcp_client {
  38         DHCPState state;
  39         sd_event *event;
  40         int event_priority;
  41         sd_event_source *timeout_resend;
  42         int index;
  43         int fd;
  44         union sockaddr_union link;
  45         sd_event_source *receive_message;
  46         uint8_t *req_opts;
  47         size_t req_opts_allocated;
  48         size_t req_opts_size;
  49         be32_t last_addr;
  50         struct ether_addr mac_addr;
  51         uint32_t xid;
  52         usec_t start_time;
  53         uint16_t secs;
  54         unsigned int attempt;
  55         usec_t request_sent;
  56         sd_event_source *timeout_t1;
  57         sd_event_source *timeout_t2;
  58         sd_event_source *timeout_expire;
  59         sd_dhcp_client_cb_t cb;
  60         void *userdata;
  61         sd_dhcp_lease *lease;
  62 };
  63
  64 static const uint8_t default_req_opts[] = {
  65         DHCP_OPTION_SUBNET_MASK,
  66         DHCP_OPTION_ROUTER,
  67         DHCP_OPTION_HOST_NAME,
  68         DHCP_OPTION_DOMAIN_NAME,
  69         DHCP_OPTION_DOMAIN_NAME_SERVER,
  70         DHCP_OPTION_NTP_SERVER,
  71 };
  72
  73 static int client_receive_message(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_CLIENT_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_CLIENT_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_CLIENT_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                                                    &request->dhcp,
 328                                                    len - DHCP_IP_UDP_SIZE);
 329         } else {
 330                 dhcp_packet_append_ip_headers(request, BOOTREQUEST, len);
 331
 332                 err = dhcp_network_send_raw_socket(client->fd, &client->link,
 333                                                    request, len);
 334         }
 335
 336         return err;
 337 }
 338
 339 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 340 {
 341         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 342
 343         return client->secs;
 344 }
 345
 346 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 347                                  void *userdata) {
 348         sd_dhcp_client *client = userdata;
 349         usec_t next_timeout = 0;
 350         uint32_t time_left;
 351         int r = 0;
 352
 353         assert(s);
 354         assert(client);
 355         assert(client->event);
 356
 357         switch (client->state) {
 358         case DHCP_STATE_RENEWING:
 359
 360                 time_left = (client->lease->t2 - client->lease->t1)/2;
 361                 if (time_left < 60)
 362                         time_left = 60;
 363
 364                 next_timeout = usec + time_left * USEC_PER_SEC;
 365
 366                 break;
 367
 368         case DHCP_STATE_REBINDING:
 369
 370                 time_left = (client->lease->lifetime - client->lease->t2)/2;
 371                 if (time_left < 60)
 372                         time_left = 60;
 373
 374                 next_timeout = usec + time_left * USEC_PER_SEC;
 375                 break;
 376
 377         case DHCP_STATE_INIT:
 378         case DHCP_STATE_INIT_REBOOT:
 379         case DHCP_STATE_REBOOTING:
 380         case DHCP_STATE_SELECTING:
 381         case DHCP_STATE_REQUESTING:
 382         case DHCP_STATE_BOUND:
 383
 384                 if (client->attempt < 64)
 385                         client->attempt *= 2;
 386
 387                 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
 388
 389                 break;
 390         }
 391
 392         next_timeout += (random_u32() & 0x1fffff);
 393
 394         r = sd_event_add_monotonic(client->event, next_timeout,
 395                                      10 * USEC_PER_MSEC,
 396                                      client_timeout_resend, client,
 397                                      &client->timeout_resend);
 398         if (r < 0)
 399                 goto error;
 400
 401         r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
 402         if (r < 0)
 403                 goto error;
 404
 405         switch (client->state) {
 406         case DHCP_STATE_INIT:
 407
 408                 client_update_secs(client, usec);
 409
 410                 r = client_send_discover(client, client->secs);
 411                 if (r >= 0) {
 412                         client->state = DHCP_STATE_SELECTING;
 413                         client->attempt = 1;
 414                 } else {
 415                         if (client->attempt >= 64)
 416                                 goto error;
 417                 }
 418
 419                 break;
 420
 421         case DHCP_STATE_SELECTING:
 422                 client_update_secs(client, usec);
 423
 424                 r = client_send_discover(client, client->secs);
 425                 if (r < 0 && client->attempt >= 64)
 426                         goto error;
 427
 428                 break;
 429
 430         case DHCP_STATE_REQUESTING:
 431         case DHCP_STATE_RENEWING:
 432         case DHCP_STATE_REBINDING:
 433                 r = client_send_request(client, client->secs);
 434                 if (r < 0 && client->attempt >= 64)
 435                          goto error;
 436
 437                 client->request_sent = usec;
 438
 439                 break;
 440
 441         case DHCP_STATE_INIT_REBOOT:
 442         case DHCP_STATE_REBOOTING:
 443         case DHCP_STATE_BOUND:
 444
 445                 break;
 446         }
 447
 448         return 0;
 449
 450 error:
 451         client_stop(client, r);
 452
 453         /* Errors were dealt with when stopping the client, don't spill
 454            errors into the event loop handler */
 455         return 0;
 456 }
 457
 458 static int client_initialize_events(sd_dhcp_client *client, usec_t usec) {
 459         int r;
 460
 461         assert(client);
 462         assert(client->event);
 463
 464         r = sd_event_add_io(client->event, client->fd, EPOLLIN,
 465                             client_receive_message, client,
 466                             &client->receive_message);
 467         if (r < 0)
 468                 goto error;
 469
 470         r = sd_event_source_set_priority(client->receive_message, client->event_priority);
 471         if (r < 0)
 472                 goto error;
 473
 474         r = sd_event_add_monotonic(client->event, usec, 0,
 475                                    client_timeout_resend, client,
 476                                    &client->timeout_resend);
 477         if (r < 0)
 478                 goto error;
 479
 480         r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
 481
 482 error:
 483         if (r < 0)
 484                 client_stop(client, r);
 485
 486         return 0;
 487
 488 }
 489
 490 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 491                                  void *userdata) {
 492         sd_dhcp_client *client = userdata;
 493
 494         client_stop(client, DHCP_EVENT_EXPIRED);
 495
 496         return 0;
 497 }
 498
 499 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 500         sd_dhcp_client *client = userdata;
 501         int r;
 502
 503         if (client->fd >= 0) {
 504                 client->receive_message =
 505                         sd_event_source_unref(client->receive_message);
 506                 close(client->fd);
 507                 client->fd = -1;
 508         }
 509
 510         client->state = DHCP_STATE_REBINDING;
 511         client->attempt = 1;
 512
 513         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 514         if (r < 0) {
 515                 client_stop(client, r);
 516                 return 0;
 517         }
 518
 519         client->fd = r;
 520
 521         return client_initialize_events(client, usec);
 522 }
 523
 524 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
 525         sd_dhcp_client *client = userdata;
 526         int r;
 527
 528         client->state = DHCP_STATE_RENEWING;
 529         client->attempt = 1;
 530
 531         r = dhcp_network_bind_udp_socket(client->index,
 532                                          client->lease->address);
 533         if (r < 0) {
 534                 client_stop(client, r);
 535                 return 0;
 536         }
 537
 538         client->fd = r;
 539
 540         return client_initialize_events(client, usec);
 541 }
 542
 543 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
 544                                  size_t len) {
 545         int r;
 546
 547         r = dhcp_packet_verify_headers(message, BOOTREPLY, len);
 548         if (r < 0)
 549                 return r;
 550
 551         if (be32toh(message->dhcp.xid) != client->xid)
 552                 return -EINVAL;
 553
 554         if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
 555                     ETHER_ADDR_LEN))
 556                 return -EINVAL;
 557
 558         return 0;
 559 }
 560
 561 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
 562                                 size_t len) {
 563         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 564         int r;
 565
 566         r = client_verify_headers(client, offer, len);
 567         if (r < 0)
 568                 return r;
 569
 570         r = dhcp_lease_new(&lease);
 571         if (r < 0)
 572                 return r;
 573
 574         len = len - DHCP_IP_UDP_SIZE;
 575         r = dhcp_option_parse(&offer->dhcp, len, dhcp_lease_parse_options,
 576                               lease);
 577         if (r != DHCP_OFFER)
 578                 return -ENOMSG;
 579
 580         lease->address = offer->dhcp.yiaddr;
 581
 582         if (lease->address == INADDR_ANY ||
 583             lease->server_address == INADDR_ANY ||
 584             lease->subnet_mask == INADDR_ANY ||
 585             lease->lifetime == 0)
 586                 return -ENOMSG;
 587
 588         client->lease = lease;
 589         lease = NULL;
 590
 591         return 0;
 592 }
 593
 594 static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
 595                               size_t len) {
 596         DHCPPacket *ack;
 597         DHCPMessage *dhcp;
 598         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 599         int r;
 600
 601         if (client->state == DHCP_STATE_RENEWING) {
 602                 dhcp = (DHCPMessage *)buf;
 603         } else {
 604                 ack = (DHCPPacket *)buf;
 605
 606                 r = client_verify_headers(client, ack, len);
 607                 if (r < 0)
 608                         return r;
 609
 610                 dhcp = &ack->dhcp;
 611                 len -= DHCP_IP_UDP_SIZE;
 612         }
 613
 614         r = dhcp_lease_new(&lease);
 615         if (r < 0)
 616                 return r;
 617
 618         r = dhcp_option_parse(dhcp, len, dhcp_lease_parse_options, lease);
 619         if (r == DHCP_NAK)
 620                 return DHCP_EVENT_NO_LEASE;
 621
 622         if (r != DHCP_ACK)
 623                 return -ENOMSG;
 624
 625         lease->address = dhcp->yiaddr;
 626
 627         if (lease->address == INADDR_ANY ||
 628             lease->server_address == INADDR_ANY ||
 629             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 630                 return -ENOMSG;
 631
 632         r = DHCP_EVENT_IP_ACQUIRE;
 633         if (client->lease) {
 634                 if (client->lease->address != lease->address ||
 635                     client->lease->subnet_mask != lease->subnet_mask ||
 636                     client->lease->router != lease->router) {
 637                         r = DHCP_EVENT_IP_CHANGE;
 638                 }
 639
 640                 client->lease = sd_dhcp_lease_unref(client->lease);
 641         }
 642
 643         client->lease = lease;
 644         lease = NULL;
 645
 646         return r;
 647 }
 648
 649 static uint64_t client_compute_timeout(uint64_t request_sent,
 650                                        uint32_t lifetime) {
 651         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 652                 + (random_u32() & 0x1fffff);
 653 }
 654
 655 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 656         uint64_t next_timeout;
 657         int r;
 658
 659         assert(client);
 660         assert(client->event);
 661
 662         if (client->lease->lifetime < 10)
 663                 return -EINVAL;
 664
 665         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 666         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 667         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 668
 669         if (!client->lease->t1)
 670                 client->lease->t1 = client->lease->lifetime / 2;
 671
 672         next_timeout = client_compute_timeout(client->request_sent,
 673                                               client->lease->t1);
 674         if (next_timeout < usec)
 675                 return -EINVAL;
 676
 677         r = sd_event_add_monotonic(client->event, next_timeout,
 678                                      10 * USEC_PER_MSEC,
 679                                      client_timeout_t1, client,
 680                                      &client->timeout_t1);
 681         if (r < 0)
 682                 return r;
 683
 684         r = sd_event_source_set_priority(client->timeout_t1, client->event_priority);
 685         if (r < 0)
 686                 return r;
 687
 688         if (!client->lease->t2)
 689                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 690
 691         if (client->lease->t2 < client->lease->t1)
 692                 return -EINVAL;
 693
 694         if (client->lease->lifetime < client->lease->t2)
 695                 return -EINVAL;
 696
 697         next_timeout = client_compute_timeout(client->request_sent,
 698                                               client->lease->t2);
 699         if (next_timeout < usec)
 700                 return -EINVAL;
 701
 702         r = sd_event_add_monotonic(client->event, next_timeout,
 703                                      10 * USEC_PER_MSEC,
 704                                      client_timeout_t2, client,
 705                                      &client->timeout_t2);
 706         if (r < 0)
 707                 return r;
 708
 709         r = sd_event_source_set_priority(client->timeout_t2, client->event_priority);
 710         if (r < 0)
 711                 return r;
 712
 713         next_timeout = client_compute_timeout(client->request_sent,
 714                                               client->lease->lifetime);
 715         if (next_timeout < usec)
 716                 return -EINVAL;
 717
 718         r = sd_event_add_monotonic(client->event, next_timeout,
 719                                      10 * USEC_PER_MSEC,
 720                                      client_timeout_expire, client,
 721                                      &client->timeout_expire);
 722         if (r < 0)
 723                 return r;
 724
 725         r = sd_event_source_set_priority(client->timeout_expire, client->event_priority);
 726         if (r < 0)
 727                 return r;
 728
 729         return 0;
 730 }
 731
 732 static int client_receive_message(sd_event_source *s, int fd,
 733                                   uint32_t revents, void *userdata) {
 734         sd_dhcp_client *client = userdata;
 735         uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
 736         int buflen = sizeof(buf);
 737         int len, r = 0, notify_event = 0;
 738         DHCPPacket *message;
 739         usec_t time_now;
 740
 741         assert(s);
 742         assert(client);
 743         assert(client->event);
 744
 745         len = read(fd, &buf, buflen);
 746         if (len < 0)
 747                 return 0;
 748
 749         r = sd_event_get_now_monotonic(client->event, &time_now);
 750         if (r < 0)
 751                 goto error;
 752
 753         switch (client->state) {
 754         case DHCP_STATE_SELECTING:
 755
 756                 message = (DHCPPacket *)&buf;
 757
 758                 if (client_receive_offer(client, message, len) >= 0) {
 759
 760                         client->timeout_resend =
 761                                 sd_event_source_unref(client->timeout_resend);
 762
 763                         client->state = DHCP_STATE_REQUESTING;
 764                         client->attempt = 1;
 765
 766                         r = sd_event_add_monotonic(client->event, time_now, 0,
 767                                                    client_timeout_resend,
 768                                                    client,
 769                                                    &client->timeout_resend);
 770                         if (r < 0)
 771                                 goto error;
 772
 773                         r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
 774                         if (r < 0)
 775                                 goto error;
 776                 }
 777
 778                 break;
 779
 780         case DHCP_STATE_REQUESTING:
 781         case DHCP_STATE_RENEWING:
 782         case DHCP_STATE_REBINDING:
 783
 784                 r = client_receive_ack(client, buf, len);
 785
 786                 if (r == DHCP_EVENT_NO_LEASE)
 787                         goto error;
 788
 789                 if (r >= 0) {
 790                         client->timeout_resend =
 791                                 sd_event_source_unref(client->timeout_resend);
 792
 793                         if (client->state == DHCP_STATE_REQUESTING)
 794                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 795                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 796                                 notify_event = r;
 797
 798                         client->state = DHCP_STATE_BOUND;
 799                         client->attempt = 1;
 800
 801                         client->last_addr = client->lease->address;
 802
 803                         r = client_set_lease_timeouts(client, time_now);
 804                         if (r < 0)
 805                                 goto error;
 806
 807                         if (notify_event)
 808                                 client_notify(client, notify_event);
 809
 810                         client->receive_message =
 811                                 sd_event_source_unref(client->receive_message);
 812                         close(client->fd);
 813                         client->fd = -1;
 814                 }
 815
 816                 r = 0;
 817
 818                 break;
 819
 820         case DHCP_STATE_INIT:
 821         case DHCP_STATE_INIT_REBOOT:
 822         case DHCP_STATE_REBOOTING:
 823         case DHCP_STATE_BOUND:
 824
 825                 break;
 826         }
 827
 828 error:
 829         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 830                 return client_stop(client, r);
 831
 832         return 0;
 833 }
 834
 835 int sd_dhcp_client_start(sd_dhcp_client *client) {
 836         int r;
 837
 838         assert_return(client, -EINVAL);
 839         assert_return(client->event, -EINVAL);
 840         assert_return(client->index > 0, -EINVAL);
 841         assert_return(client->state == DHCP_STATE_INIT ||
 842                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 843
 844         client->xid = random_u32();
 845
 846         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 847
 848         if (r < 0) {
 849                 client_stop(client, r);
 850                 return r;
 851         }
 852
 853         client->fd = r;
 854         client->start_time = now(CLOCK_MONOTONIC);
 855         client->secs = 0;
 856
 857         return client_initialize_events(client, client->start_time);
 858 }
 859
 860 int sd_dhcp_client_stop(sd_dhcp_client *client) {
 861         return client_stop(client, DHCP_EVENT_STOP);
 862 }
 863
 864 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) {
 865         int r;
 866
 867         assert_return(client, -EINVAL);
 868         assert_return(!client->event, -EBUSY);
 869
 870         if (event)
 871                 client->event = sd_event_ref(event);
 872         else {
 873                 r = sd_event_default(&client->event);
 874                 if (r < 0)
 875                         return 0;
 876         }
 877
 878         client->event_priority = priority;
 879
 880         return 0;
 881 }
 882
 883 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
 884         assert_return(client, -EINVAL);
 885
 886         client->event = sd_event_unref(client->event);
 887
 888         return 0;
 889 }
 890
 891 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
 892         if (!client)
 893                 return NULL;
 894
 895         return client->event;
 896 }
 897
 898 void sd_dhcp_client_free(sd_dhcp_client *client) {
 899         if (!client)
 900                 return;
 901
 902         sd_dhcp_client_stop(client);
 903         sd_dhcp_client_detach_event(client);
 904
 905         free(client->req_opts);
 906         free(client);
 907 }
 908
 909 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
 910 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
 911
 912 int sd_dhcp_client_new(sd_dhcp_client **ret) {
 913         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
 914
 915         assert_return(ret, -EINVAL);
 916
 917         client = new0(sd_dhcp_client, 1);
 918         if (!client)
 919                 return -ENOMEM;
 920
 921         client->state = DHCP_STATE_INIT;
 922         client->index = -1;
 923         client->fd = -1;
 924         client->attempt = 1;
 925
 926         client->req_opts_size = ELEMENTSOF(default_req_opts);
 927
 928         client->req_opts = memdup(default_req_opts, client->req_opts_size);
 929         if (!client->req_opts)
 930                 return -ENOMEM;
 931
 932         *ret = client;
 933         client = NULL;
 934
 935         return 0;
 936 }