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                                                    &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,
 402                                          client->event_priority);
 403         if (r < 0)
 404                 goto error;
 405
 406         switch (client->state) {
 407         case DHCP_STATE_INIT:
 408
 409                 client_update_secs(client, usec);
 410
 411                 r = client_send_discover(client, client->secs);
 412                 if (r >= 0) {
 413                         client->state = DHCP_STATE_SELECTING;
 414                         client->attempt = 1;
 415                 } else {
 416                         if (client->attempt >= 64)
 417                                 goto error;
 418                 }
 419
 420                 break;
 421
 422         case DHCP_STATE_SELECTING:
 423                 client_update_secs(client, usec);
 424
 425                 r = client_send_discover(client, client->secs);
 426                 if (r < 0 && client->attempt >= 64)
 427                         goto error;
 428
 429                 break;
 430
 431         case DHCP_STATE_REQUESTING:
 432         case DHCP_STATE_RENEWING:
 433         case DHCP_STATE_REBINDING:
 434                 r = client_send_request(client, client->secs);
 435                 if (r < 0 && client->attempt >= 64)
 436                          goto error;
 437
 438                 client->request_sent = usec;
 439
 440                 break;
 441
 442         case DHCP_STATE_INIT_REBOOT:
 443         case DHCP_STATE_REBOOTING:
 444         case DHCP_STATE_BOUND:
 445
 446                 break;
 447         }
 448
 449         return 0;
 450
 451 error:
 452         client_stop(client, r);
 453
 454         /* Errors were dealt with when stopping the client, don't spill
 455            errors into the event loop handler */
 456         return 0;
 457 }
 458
 459 static int client_initialize_events(sd_dhcp_client *client,
 460                                     sd_event_io_handler_t io_callback,
 461                                     usec_t usec) {
 462         int r;
 463
 464         assert(client);
 465         assert(client->event);
 466
 467         r = sd_event_add_io(client->event, client->fd, EPOLLIN, io_callback,
 468                             client, &client->receive_message);
 469         if (r < 0)
 470                 goto error;
 471
 472         r = sd_event_source_set_priority(client->receive_message,
 473                                          client->event_priority);
 474         if (r < 0)
 475                 goto error;
 476
 477         r = sd_event_add_monotonic(client->event, usec, 0,
 478                                    client_timeout_resend, client,
 479                                    &client->timeout_resend);
 480         if (r < 0)
 481                 goto error;
 482
 483         r = sd_event_source_set_priority(client->timeout_resend,
 484                                          client->event_priority);
 485
 486 error:
 487         if (r < 0)
 488                 client_stop(client, r);
 489
 490         return 0;
 491
 492 }
 493
 494 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 495                                  void *userdata) {
 496         sd_dhcp_client *client = userdata;
 497
 498         client_stop(client, DHCP_EVENT_EXPIRED);
 499
 500         return 0;
 501 }
 502
 503 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 504         sd_dhcp_client *client = userdata;
 505         int r;
 506
 507         if (client->fd >= 0) {
 508                 client->receive_message =
 509                         sd_event_source_unref(client->receive_message);
 510                 close(client->fd);
 511                 client->fd = -1;
 512         }
 513
 514         client->state = DHCP_STATE_REBINDING;
 515         client->attempt = 1;
 516
 517         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 518         if (r < 0) {
 519                 client_stop(client, r);
 520                 return 0;
 521         }
 522
 523         client->fd = r;
 524
 525         return client_initialize_events(client, client_receive_message_raw,
 526                                         usec);
 527 }
 528
 529 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 530                              void *userdata) {
 531         sd_dhcp_client *client = userdata;
 532         int r;
 533
 534         client->state = DHCP_STATE_RENEWING;
 535         client->attempt = 1;
 536
 537         r = dhcp_network_bind_udp_socket(client->index,
 538                                          client->lease->address);
 539         if (r < 0) {
 540                 client_stop(client, r);
 541                 return 0;
 542         }
 543
 544         client->fd = r;
 545
 546         return client_initialize_events(client, client_receive_message_udp, usec);
 547 }
 548
 549 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 550                                size_t len) {
 551         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 552         int r;
 553
 554         r = dhcp_lease_new(&lease);
 555         if (r < 0)
 556                 return r;
 557
 558         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 559         if (r != DHCP_OFFER)
 560                 return -ENOMSG;
 561
 562         lease->address = offer->yiaddr;
 563
 564         if (lease->address == INADDR_ANY ||
 565             lease->server_address == INADDR_ANY ||
 566             lease->subnet_mask == INADDR_ANY ||
 567             lease->lifetime == 0)
 568                 return -ENOMSG;
 569
 570         client->lease = lease;
 571         lease = NULL;
 572
 573         return 0;
 574 }
 575
 576 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 577                              size_t len) {
 578         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 579         int r;
 580
 581         r = dhcp_lease_new(&lease);
 582         if (r < 0)
 583                 return r;
 584
 585         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 586         if (r == DHCP_NAK)
 587                 return DHCP_EVENT_NO_LEASE;
 588
 589         if (r != DHCP_ACK)
 590                 return -ENOMSG;
 591
 592         lease->address = ack->yiaddr;
 593
 594         if (lease->address == INADDR_ANY ||
 595             lease->server_address == INADDR_ANY ||
 596             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 597                 return -ENOMSG;
 598
 599         r = DHCP_EVENT_IP_ACQUIRE;
 600         if (client->lease) {
 601                 if (client->lease->address != lease->address ||
 602                     client->lease->subnet_mask != lease->subnet_mask ||
 603                     client->lease->router != lease->router) {
 604                         r = DHCP_EVENT_IP_CHANGE;
 605                 }
 606
 607                 client->lease = sd_dhcp_lease_unref(client->lease);
 608         }
 609
 610         client->lease = lease;
 611         lease = NULL;
 612
 613         return r;
 614 }
 615
 616 static uint64_t client_compute_timeout(uint64_t request_sent,
 617                                        uint32_t lifetime) {
 618         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 619                 + (random_u32() & 0x1fffff);
 620 }
 621
 622 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 623         uint64_t next_timeout;
 624         int r;
 625
 626         assert(client);
 627         assert(client->event);
 628
 629         if (client->lease->lifetime < 10)
 630                 return -EINVAL;
 631
 632         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 633         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 634         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 635
 636         if (!client->lease->t1)
 637                 client->lease->t1 = client->lease->lifetime / 2;
 638
 639         next_timeout = client_compute_timeout(client->request_sent,
 640                                               client->lease->t1);
 641         if (next_timeout < usec)
 642                 return -EINVAL;
 643
 644         r = sd_event_add_monotonic(client->event, next_timeout,
 645                                      10 * USEC_PER_MSEC,
 646                                      client_timeout_t1, client,
 647                                      &client->timeout_t1);
 648         if (r < 0)
 649                 return r;
 650
 651         r = sd_event_source_set_priority(client->timeout_t1,
 652                                          client->event_priority);
 653         if (r < 0)
 654                 return r;
 655
 656         if (!client->lease->t2)
 657                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 658
 659         if (client->lease->t2 < client->lease->t1)
 660                 return -EINVAL;
 661
 662         if (client->lease->lifetime < client->lease->t2)
 663                 return -EINVAL;
 664
 665         next_timeout = client_compute_timeout(client->request_sent,
 666                                               client->lease->t2);
 667         if (next_timeout < usec)
 668                 return -EINVAL;
 669
 670         r = sd_event_add_monotonic(client->event, next_timeout,
 671                                      10 * USEC_PER_MSEC,
 672                                      client_timeout_t2, client,
 673                                      &client->timeout_t2);
 674         if (r < 0)
 675                 return r;
 676
 677         r = sd_event_source_set_priority(client->timeout_t2,
 678                                          client->event_priority);
 679         if (r < 0)
 680                 return r;
 681
 682         next_timeout = client_compute_timeout(client->request_sent,
 683                                               client->lease->lifetime);
 684         if (next_timeout < usec)
 685                 return -EINVAL;
 686
 687         r = sd_event_add_monotonic(client->event, next_timeout,
 688                                      10 * USEC_PER_MSEC,
 689                                      client_timeout_expire, client,
 690                                      &client->timeout_expire);
 691         if (r < 0)
 692                 return r;
 693
 694         r = sd_event_source_set_priority(client->timeout_expire,
 695                                          client->event_priority);
 696         if (r < 0)
 697                 return r;
 698
 699         return 0;
 700 }
 701
 702 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 703                                  int len, usec_t time_now) {
 704         int r = 0, notify_event = 0;
 705
 706         assert(client);
 707         assert(client->event);
 708         assert(message);
 709
 710         if (be32toh(message->xid) != client->xid)
 711                 return -EINVAL;
 712
 713         if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
 714                    ETHER_ADDR_LEN))
 715                 return -EINVAL;
 716
 717         switch (client->state) {
 718         case DHCP_STATE_SELECTING:
 719
 720                 r = client_handle_offer(client, message, len);
 721                 if (r >= 0) {
 722
 723                         client->timeout_resend =
 724                                 sd_event_source_unref(client->timeout_resend);
 725
 726                         client->state = DHCP_STATE_REQUESTING;
 727                         client->attempt = 1;
 728
 729                         r = sd_event_add_monotonic(client->event, time_now, 0,
 730                                                    client_timeout_resend,
 731                                                    client,
 732                                                    &client->timeout_resend);
 733                         if (r < 0)
 734                                 goto error;
 735
 736                         r = sd_event_source_set_priority(client->timeout_resend,
 737                                                          client->event_priority);
 738                         if (r < 0)
 739                                 goto error;
 740                 }
 741
 742                 break;
 743
 744         case DHCP_STATE_REQUESTING:
 745         case DHCP_STATE_RENEWING:
 746         case DHCP_STATE_REBINDING:
 747
 748                 r = client_handle_ack(client, message, len);
 749
 750                 if (r == DHCP_EVENT_NO_LEASE)
 751                         goto error;
 752
 753                 if (r >= 0) {
 754                         client->timeout_resend =
 755                                 sd_event_source_unref(client->timeout_resend);
 756
 757                         if (client->state == DHCP_STATE_REQUESTING)
 758                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 759                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 760                                 notify_event = r;
 761
 762                         client->state = DHCP_STATE_BOUND;
 763                         client->attempt = 1;
 764
 765                         client->last_addr = client->lease->address;
 766
 767                         r = client_set_lease_timeouts(client, time_now);
 768                         if (r < 0)
 769                                 goto error;
 770
 771                         if (notify_event)
 772                                 client_notify(client, notify_event);
 773
 774                         client->receive_message =
 775                                 sd_event_source_unref(client->receive_message);
 776                         close(client->fd);
 777                         client->fd = -1;
 778                 }
 779
 780                 r = 0;
 781
 782                 break;
 783
 784         case DHCP_STATE_INIT:
 785         case DHCP_STATE_INIT_REBOOT:
 786         case DHCP_STATE_REBOOTING:
 787         case DHCP_STATE_BOUND:
 788
 789                 break;
 790         }
 791
 792 error:
 793         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 794                 return client_stop(client, r);
 795
 796         return 0;
 797 }
 798
 799 static int client_receive_message_raw(sd_event_source *s, int fd,
 800                                       uint32_t revents, void *userdata) {
 801         sd_dhcp_client *client = userdata;
 802         uint8_t buf[sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE];
 803         int buflen = sizeof(buf);
 804         int len, r = 0;
 805         usec_t time_now;
 806
 807         assert(s);
 808         assert(client);
 809         assert(client->event);
 810
 811         len = read(fd, &buf, buflen);
 812         if (len < 0)
 813                 return 0;
 814
 815         r = sd_event_get_now_monotonic(client->event, &time_now);
 816         if (r < 0)
 817                 return client_stop(client, r);
 818
 819         return client_handle_message(client, (DHCPMessage *) buf, len,
 820                                      time_now);
 821 }
 822
 823 static int client_receive_message_udp(sd_event_source *s, int fd,
 824                                       uint32_t revents, void *userdata) {
 825         sd_dhcp_client *client = userdata;
 826         uint8_t buf[sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE];
 827         int buflen = sizeof(buf);
 828         int len, r = 0;
 829         DHCPPacket *packet;
 830         usec_t time_now;
 831
 832         assert(s);
 833         assert(client);
 834         assert(client->event);
 835
 836         len = read(fd, &buf, buflen);
 837         if (len < 0)
 838                 return 0;
 839
 840         packet = (DHCPPacket *) buf;
 841
 842         r = dhcp_packet_verify_headers(packet, BOOTREPLY, len);
 843         if (r < 0)
 844                 return r;
 845
 846         len -= DHCP_IP_UDP_SIZE;
 847
 848         r = sd_event_get_now_monotonic(client->event, &time_now);
 849         if (r < 0)
 850                 return client_stop(client, r);
 851
 852         return client_handle_message(client, &packet->dhcp, len, time_now);
 853 }
 854
 855 int sd_dhcp_client_start(sd_dhcp_client *client) {
 856         int r;
 857
 858         assert_return(client, -EINVAL);
 859         assert_return(client->event, -EINVAL);
 860         assert_return(client->index > 0, -EINVAL);
 861         assert_return(client->state == DHCP_STATE_INIT ||
 862                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 863
 864         client->xid = random_u32();
 865
 866         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 867
 868         if (r < 0) {
 869                 client_stop(client, r);
 870                 return r;
 871         }
 872
 873         client->fd = r;
 874         client->start_time = now(CLOCK_MONOTONIC);
 875         client->secs = 0;
 876
 877         return client_initialize_events(client, client_receive_message_udp,
 878                                         client->start_time);
 879 }
 880
 881 int sd_dhcp_client_stop(sd_dhcp_client *client) {
 882         return client_stop(client, DHCP_EVENT_STOP);
 883 }
 884
 885 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
 886                                 int priority) {
 887         int r;
 888
 889         assert_return(client, -EINVAL);
 890         assert_return(!client->event, -EBUSY);
 891
 892         if (event)
 893                 client->event = sd_event_ref(event);
 894         else {
 895                 r = sd_event_default(&client->event);
 896                 if (r < 0)
 897                         return 0;
 898         }
 899
 900         client->event_priority = priority;
 901
 902         return 0;
 903 }
 904
 905 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
 906         assert_return(client, -EINVAL);
 907
 908         client->event = sd_event_unref(client->event);
 909
 910         return 0;
 911 }
 912
 913 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
 914         if (!client)
 915                 return NULL;
 916
 917         return client->event;
 918 }
 919
 920 void sd_dhcp_client_free(sd_dhcp_client *client) {
 921         if (!client)
 922                 return;
 923
 924         sd_dhcp_client_stop(client);
 925         sd_dhcp_client_detach_event(client);
 926
 927         free(client->req_opts);
 928         free(client);
 929 }
 930
 931 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
 932 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
 933
 934 int sd_dhcp_client_new(sd_dhcp_client **ret) {
 935         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
 936
 937         assert_return(ret, -EINVAL);
 938
 939         client = new0(sd_dhcp_client, 1);
 940         if (!client)
 941                 return -ENOMEM;
 942
 943         client->state = DHCP_STATE_INIT;
 944         client->index = -1;
 945         client->fd = -1;
 946         client->attempt = 1;
 947
 948         client->req_opts_size = ELEMENTSOF(default_req_opts);
 949
 950         client->req_opts = memdup(default_req_opts, client->req_opts_size);
 951         if (!client->req_opts)
 952                 return -ENOMEM;
 953
 954         *ret = client;
 955         client = NULL;
 956
 957         return 0;
 958 }