src/libsystemd-network/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 #include <sys/ioctl.h>
  27
  28 #include "util.h"
  29 #include "list.h"
  30
  31 #include "dhcp-protocol.h"
  32 #include "dhcp-internal.h"
  33 #include "dhcp-lease-internal.h"
  34 #include "sd-dhcp-client.h"
  35
  36 struct sd_dhcp_client {
  37         DHCPState state;
  38         sd_event *event;
  39         int event_priority;
  40         sd_event_source *timeout_resend;
  41         int index;
  42         int fd;
  43         union sockaddr_union link;
  44         sd_event_source *receive_message;
  45         uint8_t *req_opts;
  46         size_t req_opts_allocated;
  47         size_t req_opts_size;
  48         be32_t last_addr;
  49         struct ether_addr mac_addr;
  50         uint32_t xid;
  51         usec_t start_time;
  52         uint16_t secs;
  53         unsigned int attempt;
  54         usec_t request_sent;
  55         sd_event_source *timeout_t1;
  56         sd_event_source *timeout_t2;
  57         sd_event_source *timeout_expire;
  58         sd_dhcp_client_cb_t cb;
  59         void *userdata;
  60         sd_dhcp_lease *lease;
  61 };
  62
  63 static const uint8_t default_req_opts[] = {
  64         DHCP_OPTION_SUBNET_MASK,
  65         DHCP_OPTION_ROUTER,
  66         DHCP_OPTION_HOST_NAME,
  67         DHCP_OPTION_DOMAIN_NAME,
  68         DHCP_OPTION_DOMAIN_NAME_SERVER,
  69         DHCP_OPTION_NTP_SERVER,
  70 };
  71
  72 static int client_receive_message_raw(sd_event_source *s, int fd,
  73                                       uint32_t revents, void *userdata);
  74 static int client_receive_message_udp(sd_event_source *s, int fd,
  75                                       uint32_t revents, void *userdata);
  76
  77 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
  78                                 void *userdata) {
  79         assert_return(client, -EINVAL);
  80
  81         client->cb = cb;
  82         client->userdata = userdata;
  83
  84         return 0;
  85 }
  86
  87 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
  88         size_t i;
  89
  90         assert_return(client, -EINVAL);
  91         assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
  92
  93         switch(option) {
  94         case DHCP_OPTION_PAD:
  95         case DHCP_OPTION_OVERLOAD:
  96         case DHCP_OPTION_MESSAGE_TYPE:
  97         case DHCP_OPTION_PARAMETER_REQUEST_LIST:
  98         case DHCP_OPTION_END:
  99                 return -EINVAL;
 100
 101         default:
 102                 break;
 103         }
 104
 105         for (i = 0; i < client->req_opts_size; i++)
 106                 if (client->req_opts[i] == option)
 107                         return -EEXIST;
 108
 109         if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
 110                             client->req_opts_size + 1))
 111                 return -ENOMEM;
 112
 113         client->req_opts[client->req_opts_size++] = option;
 114
 115         return 0;
 116 }
 117
 118 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
 119                                        const struct in_addr *last_addr) {
 120         assert_return(client, -EINVAL);
 121         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 122
 123         if (last_addr)
 124                 client->last_addr = last_addr->s_addr;
 125         else
 126                 client->last_addr = INADDR_ANY;
 127
 128         return 0;
 129 }
 130
 131 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
 132         assert_return(client, -EINVAL);
 133         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 134         assert_return(interface_index >= -1, -EINVAL);
 135
 136         client->index = interface_index;
 137
 138         return 0;
 139 }
 140
 141 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
 142                            const struct ether_addr *addr) {
 143         assert_return(client, -EINVAL);
 144         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 145
 146         log_dhcp_client(client, "set MAC address to "
 147                         "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
 148                         addr->ether_addr_octet[0],
 149                         addr->ether_addr_octet[1],
 150                         addr->ether_addr_octet[2],
 151                         addr->ether_addr_octet[3],
 152                         addr->ether_addr_octet[4],
 153                         addr->ether_addr_octet[5]);
 154
 155         memcpy(&client->mac_addr, addr, ETH_ALEN);
 156
 157         return 0;
 158 }
 159
 160 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
 161         assert_return(client, -EINVAL);
 162         assert_return(ret, -EINVAL);
 163
 164         if (client->state != DHCP_STATE_BOUND &&
 165             client->state != DHCP_STATE_RENEWING &&
 166             client->state != DHCP_STATE_REBINDING)
 167                 return -EADDRNOTAVAIL;
 168
 169         *ret = sd_dhcp_lease_ref(client->lease);
 170
 171         return 0;
 172 }
 173
 174 static int client_notify(sd_dhcp_client *client, int event) {
 175         if (client->cb)
 176                 client->cb(client, event, client->userdata);
 177
 178         return 0;
 179 }
 180
 181 static int client_stop(sd_dhcp_client *client, int error) {
 182         assert_return(client, -EINVAL);
 183
 184         client->receive_message =
 185                 sd_event_source_unref(client->receive_message);
 186
 187         if (client->fd >= 0)
 188                 close_nointr_nofail(client->fd);
 189         client->fd = -1;
 190
 191         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 192
 193         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 194         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 195         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 196
 197         client->attempt = 1;
 198
 199         client_notify(client, error);
 200
 201         client->start_time = 0;
 202         client->secs = 0;
 203         client->state = DHCP_STATE_INIT;
 204
 205         if (client->lease)
 206                 client->lease = sd_dhcp_lease_unref(client->lease);
 207
 208         log_dhcp_client(client, "STOPPED");
 209
 210         return 0;
 211 }
 212
 213 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
 214                                uint8_t type, uint16_t secs, uint8_t **opt,
 215                                size_t *optlen) {
 216         int r;
 217
 218         assert(secs);
 219
 220         r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
 221                               optlen);
 222         if (r < 0)
 223                 return r;
 224
 225         /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
 226            refuse to issue an DHCP lease if 'secs' is set to zero */
 227         message->secs = htobe16(secs);
 228
 229         memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
 230
 231         if (client->state == DHCP_STATE_RENEWING ||
 232             client->state == DHCP_STATE_REBINDING)
 233                 message->ciaddr = client->lease->address;
 234
 235         /* Some DHCP servers will refuse to issue an DHCP lease if the Client
 236            Identifier option is not set */
 237         r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
 238                                ETH_ALEN, &client->mac_addr);
 239         if (r < 0)
 240                 return r;
 241
 242         if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
 243                 be16_t max_size;
 244
 245                 r = dhcp_option_append(opt, optlen,
 246                                        DHCP_OPTION_PARAMETER_REQUEST_LIST,
 247                                        client->req_opts_size,
 248                                        client->req_opts);
 249                 if (r < 0)
 250                         return r;
 251
 252                 /* Some DHCP servers will send bigger DHCP packets than the
 253                    defined default size unless the Maximum Messge Size option
 254                    is explicitely set */
 255                 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
 256                                    DHCP_MIN_OPTIONS_SIZE);
 257                 r = dhcp_option_append(opt, optlen,
 258                                        DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
 259                                        2, &max_size);
 260                 if (r < 0)
 261                         return r;
 262         }
 263
 264         return 0;
 265 }
 266
 267 static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
 268                                 size_t len) {
 269         dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
 270                                       INADDR_BROADCAST, DHCP_PORT_SERVER, len);
 271
 272         return dhcp_network_send_raw_socket(client->fd, &client->link,
 273                                             packet, len);
 274 }
 275
 276 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
 277         int err = 0;
 278         _cleanup_free_ DHCPPacket *discover;
 279         size_t optlen, len;
 280         uint8_t *opt;
 281
 282         optlen = DHCP_MIN_OPTIONS_SIZE;
 283         len = sizeof(DHCPPacket) + optlen;
 284
 285         discover = malloc0(len);
 286
 287         if (!discover)
 288                 return -ENOMEM;
 289
 290         err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
 291                                   secs, &opt, &optlen);
 292         if (err < 0)
 293                 return err;
 294
 295         if (client->last_addr != INADDR_ANY) {
 296                 err = dhcp_option_append(&opt, &optlen,
 297                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 298                                          4, &client->last_addr);
 299                 if (err < 0)
 300                         return err;
 301         }
 302
 303         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 304         if (err < 0)
 305                 return err;
 306
 307         err = dhcp_client_send_raw(client, discover, len);
 308         if (err < 0)
 309                 return err;
 310
 311         log_dhcp_client(client, "DISCOVER");
 312
 313         return 0;
 314 }
 315
 316 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
 317         _cleanup_free_ DHCPPacket *request;
 318         size_t optlen, len;
 319         int err;
 320         uint8_t *opt;
 321
 322         optlen = DHCP_MIN_OPTIONS_SIZE;
 323         len = sizeof(DHCPPacket) + optlen;
 324
 325         request = malloc0(len);
 326         if (!request)
 327                 return -ENOMEM;
 328
 329         err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
 330                                   &opt, &optlen);
 331         if (err < 0)
 332                 return err;
 333
 334         if (client->state == DHCP_STATE_REQUESTING) {
 335                 err = dhcp_option_append(&opt, &optlen,
 336                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 337                                          4, &client->lease->address);
 338                 if (err < 0)
 339                         return err;
 340
 341                 err = dhcp_option_append(&opt, &optlen,
 342                                          DHCP_OPTION_SERVER_IDENTIFIER,
 343                                          4, &client->lease->server_address);
 344                 if (err < 0)
 345                         return err;
 346         }
 347
 348         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 349         if (err < 0)
 350                 return err;
 351
 352         if (client->state == DHCP_STATE_RENEWING) {
 353                 err = dhcp_network_send_udp_socket(client->fd,
 354                                                    client->lease->server_address,
 355                                                    DHCP_PORT_SERVER,
 356                                                    &request->dhcp,
 357                                                    len - DHCP_IP_UDP_SIZE);
 358         } else {
 359                 err = dhcp_client_send_raw(client, request, len);
 360         }
 361         if (err < 0)
 362                 return err;
 363
 364         log_dhcp_client(client, "REQUEST");
 365
 366         return 0;
 367 }
 368
 369 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 370 {
 371         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 372
 373         return client->secs;
 374 }
 375
 376 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 377                                  void *userdata) {
 378         sd_dhcp_client *client = userdata;
 379         usec_t next_timeout = 0;
 380         uint32_t time_left;
 381         int r = 0;
 382
 383         assert(s);
 384         assert(client);
 385         assert(client->event);
 386
 387         switch (client->state) {
 388         case DHCP_STATE_RENEWING:
 389
 390                 time_left = (client->lease->t2 - client->lease->t1) / 2;
 391                 if (time_left < 60)
 392                         time_left = 60;
 393
 394                 next_timeout = usec + time_left * USEC_PER_SEC;
 395
 396                 break;
 397
 398         case DHCP_STATE_REBINDING:
 399
 400                 time_left = (client->lease->lifetime - client->lease->t2) / 2;
 401                 if (time_left < 60)
 402                         time_left = 60;
 403
 404                 next_timeout = usec + time_left * USEC_PER_SEC;
 405                 break;
 406
 407         case DHCP_STATE_INIT:
 408         case DHCP_STATE_INIT_REBOOT:
 409         case DHCP_STATE_REBOOTING:
 410         case DHCP_STATE_SELECTING:
 411         case DHCP_STATE_REQUESTING:
 412         case DHCP_STATE_BOUND:
 413
 414                 if (client->attempt < 64)
 415                         client->attempt *= 2;
 416
 417                 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
 418
 419                 break;
 420         }
 421
 422         next_timeout += (random_u32() & 0x1fffff);
 423
 424         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 425
 426         r = sd_event_add_monotonic(client->event,
 427                                      &client->timeout_resend,
 428                                      next_timeout,
 429                                      10 * USEC_PER_MSEC,
 430                                      client_timeout_resend, client);
 431         if (r < 0)
 432                 goto error;
 433
 434         r = sd_event_source_set_priority(client->timeout_resend,
 435                                          client->event_priority);
 436         if (r < 0)
 437                 goto error;
 438
 439         switch (client->state) {
 440         case DHCP_STATE_INIT:
 441
 442                 client_update_secs(client, usec);
 443
 444                 r = client_send_discover(client, client->secs);
 445                 if (r >= 0) {
 446                         client->state = DHCP_STATE_SELECTING;
 447                         client->attempt = 1;
 448                 } else {
 449                         if (client->attempt >= 64)
 450                                 goto error;
 451                 }
 452
 453                 break;
 454
 455         case DHCP_STATE_SELECTING:
 456                 client_update_secs(client, usec);
 457
 458                 r = client_send_discover(client, client->secs);
 459                 if (r < 0 && client->attempt >= 64)
 460                         goto error;
 461
 462                 break;
 463
 464         case DHCP_STATE_REQUESTING:
 465         case DHCP_STATE_RENEWING:
 466         case DHCP_STATE_REBINDING:
 467                 r = client_send_request(client, client->secs);
 468                 if (r < 0 && client->attempt >= 64)
 469                          goto error;
 470
 471                 client->request_sent = usec;
 472
 473                 break;
 474
 475         case DHCP_STATE_INIT_REBOOT:
 476         case DHCP_STATE_REBOOTING:
 477         case DHCP_STATE_BOUND:
 478
 479                 break;
 480         }
 481
 482         return 0;
 483
 484 error:
 485         client_stop(client, r);
 486
 487         /* Errors were dealt with when stopping the client, don't spill
 488            errors into the event loop handler */
 489         return 0;
 490 }
 491
 492 static int client_initialize_events(sd_dhcp_client *client,
 493                                     sd_event_io_handler_t io_callback,
 494                                     usec_t usec) {
 495         int r;
 496
 497         assert(client);
 498         assert(client->event);
 499
 500         r = sd_event_add_io(client->event, &client->receive_message,
 501                             client->fd, EPOLLIN, io_callback,
 502                             client);
 503         if (r < 0)
 504                 goto error;
 505
 506         r = sd_event_source_set_priority(client->receive_message,
 507                                          client->event_priority);
 508         if (r < 0)
 509                 goto error;
 510
 511         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 512
 513         r = sd_event_add_monotonic(client->event,
 514                                    &client->timeout_resend,
 515                                    usec, 0,
 516                                    client_timeout_resend, client);
 517         if (r < 0)
 518                 goto error;
 519
 520         r = sd_event_source_set_priority(client->timeout_resend,
 521                                          client->event_priority);
 522
 523 error:
 524         if (r < 0)
 525                 client_stop(client, r);
 526
 527         return 0;
 528
 529 }
 530
 531 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 532                                  void *userdata) {
 533         sd_dhcp_client *client = userdata;
 534
 535         log_dhcp_client(client, "EXPIRED");
 536
 537         client_stop(client, DHCP_EVENT_EXPIRED);
 538
 539         return 0;
 540 }
 541
 542 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 543         sd_dhcp_client *client = userdata;
 544         int r;
 545
 546         if (client->fd >= 0) {
 547                 client->receive_message =
 548                         sd_event_source_unref(client->receive_message);
 549                 close_nointr_nofail(client->fd);
 550                 client->fd = -1;
 551         }
 552
 553         client->state = DHCP_STATE_REBINDING;
 554         client->attempt = 1;
 555
 556         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 557         if (r < 0) {
 558                 client_stop(client, r);
 559                 return 0;
 560         }
 561
 562         client->fd = r;
 563
 564         log_dhcp_client(client, "TIMEOUT T2");
 565
 566         return client_initialize_events(client, client_receive_message_raw,
 567                                         usec);
 568 }
 569
 570 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 571                              void *userdata) {
 572         sd_dhcp_client *client = userdata;
 573         int r;
 574
 575         client->state = DHCP_STATE_RENEWING;
 576         client->attempt = 1;
 577
 578         r = dhcp_network_bind_udp_socket(client->index,
 579                                          client->lease->address,
 580                                          DHCP_PORT_CLIENT);
 581         if (r < 0) {
 582                 client_stop(client, r);
 583                 return 0;
 584         }
 585
 586         client->fd = r;
 587
 588         log_dhcp_client(client, "TIMEOUT T1");
 589
 590         return client_initialize_events(client, client_receive_message_udp, usec);
 591 }
 592
 593 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 594                                size_t len) {
 595         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 596         int r;
 597
 598         r = dhcp_lease_new(&lease);
 599         if (r < 0)
 600                 return r;
 601
 602         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 603         if (r != DHCP_OFFER)
 604                 return -ENOMSG;
 605
 606         lease->next_server = offer->siaddr;
 607
 608         lease->address = offer->yiaddr;
 609
 610         if (lease->address == INADDR_ANY ||
 611             lease->server_address == INADDR_ANY ||
 612             lease->subnet_mask == INADDR_ANY ||
 613             lease->lifetime == 0)
 614                 return -ENOMSG;
 615
 616         client->lease = lease;
 617         lease = NULL;
 618
 619         log_dhcp_client(client, "OFFER");
 620
 621         return 0;
 622 }
 623
 624 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 625                              size_t len) {
 626         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 627         int r;
 628
 629         r = dhcp_lease_new(&lease);
 630         if (r < 0)
 631                 return r;
 632
 633         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 634         if (r == DHCP_NAK) {
 635                 log_dhcp_client(client, "NAK");
 636                 return DHCP_EVENT_NO_LEASE;
 637         }
 638
 639         if (r != DHCP_ACK)
 640                 return -ENOMSG;
 641
 642         lease->next_server = ack->siaddr;
 643
 644         lease->address = ack->yiaddr;
 645
 646         if (lease->address == INADDR_ANY ||
 647             lease->server_address == INADDR_ANY ||
 648             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 649                 return -ENOMSG;
 650
 651         r = DHCP_EVENT_IP_ACQUIRE;
 652         if (client->lease) {
 653                 if (client->lease->address != lease->address ||
 654                     client->lease->subnet_mask != lease->subnet_mask ||
 655                     client->lease->router != lease->router) {
 656                         r = DHCP_EVENT_IP_CHANGE;
 657                 }
 658
 659                 client->lease = sd_dhcp_lease_unref(client->lease);
 660         }
 661
 662         client->lease = lease;
 663         lease = NULL;
 664
 665         log_dhcp_client(client, "ACK");
 666
 667         return r;
 668 }
 669
 670 static uint64_t client_compute_timeout(uint64_t request_sent,
 671                                        uint32_t lifetime) {
 672         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 673                 + (random_u32() & 0x1fffff);
 674 }
 675
 676 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 677         uint64_t next_timeout;
 678         int r;
 679
 680         assert(client);
 681         assert(client->event);
 682
 683         if (client->lease->lifetime < 10)
 684                 return -EINVAL;
 685
 686         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 687         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 688         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 689
 690         if (!client->lease->t1)
 691                 client->lease->t1 = client->lease->lifetime / 2;
 692
 693         next_timeout = client_compute_timeout(client->request_sent,
 694                                               client->lease->t1);
 695         if (next_timeout < usec)
 696                 return -EINVAL;
 697
 698         r = sd_event_add_monotonic(client->event,
 699                                      &client->timeout_t1,
 700                                      next_timeout,
 701                                      10 * USEC_PER_MSEC,
 702                                      client_timeout_t1, client);
 703         if (r < 0)
 704                 return r;
 705
 706         r = sd_event_source_set_priority(client->timeout_t1,
 707                                          client->event_priority);
 708         if (r < 0)
 709                 return r;
 710
 711         if (!client->lease->t2)
 712                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 713
 714         if (client->lease->t2 < client->lease->t1)
 715                 return -EINVAL;
 716
 717         if (client->lease->lifetime < client->lease->t2)
 718                 return -EINVAL;
 719
 720         next_timeout = client_compute_timeout(client->request_sent,
 721                                               client->lease->t2);
 722         if (next_timeout < usec)
 723                 return -EINVAL;
 724
 725         r = sd_event_add_monotonic(client->event,
 726                                      &client->timeout_t2,
 727                                      next_timeout,
 728                                      10 * USEC_PER_MSEC,
 729                                      client_timeout_t2, client);
 730         if (r < 0)
 731                 return r;
 732
 733         r = sd_event_source_set_priority(client->timeout_t2,
 734                                          client->event_priority);
 735         if (r < 0)
 736                 return r;
 737
 738         next_timeout = client_compute_timeout(client->request_sent,
 739                                               client->lease->lifetime);
 740         if (next_timeout < usec)
 741                 return -EINVAL;
 742
 743         r = sd_event_add_monotonic(client->event,
 744                                      &client->timeout_expire, next_timeout,
 745                                      10 * USEC_PER_MSEC,
 746                                      client_timeout_expire, client);
 747         if (r < 0)
 748                 return r;
 749
 750         r = sd_event_source_set_priority(client->timeout_expire,
 751                                          client->event_priority);
 752         if (r < 0)
 753                 return r;
 754
 755         return 0;
 756 }
 757
 758 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 759                                  int len, usec_t time_now) {
 760         int r = 0, notify_event = 0;
 761
 762         assert(client);
 763         assert(client->event);
 764         assert(message);
 765
 766         if (len < DHCP_MESSAGE_SIZE) {
 767                 log_dhcp_client(client, "message too small (%d bytes): "
 768                                 "ignoring", len);
 769                 return 0;
 770         }
 771
 772         if (message->op != BOOTREPLY) {
 773                 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
 774                 return 0;
 775         }
 776
 777         if (be32toh(message->xid) != client->xid) {
 778                 log_dhcp_client(client, "received xid (%u) does not match "
 779                                 "expected (%u): ignoring",
 780                                 be32toh(message->xid), client->xid);
 781                 return 0;
 782         }
 783
 784         if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
 785                    ETHER_ADDR_LEN)) {
 786                 log_dhcp_client(client, "received chaddr does not match "
 787                                 "expected: ignoring");
 788                 return 0;
 789         }
 790
 791         switch (client->state) {
 792         case DHCP_STATE_SELECTING:
 793
 794                 r = client_handle_offer(client, message, len);
 795                 if (r >= 0) {
 796
 797                         client->timeout_resend =
 798                                 sd_event_source_unref(client->timeout_resend);
 799
 800                         client->state = DHCP_STATE_REQUESTING;
 801                         client->attempt = 1;
 802
 803                         r = sd_event_add_monotonic(client->event,
 804                                                    &client->timeout_resend,
 805                                                    time_now, 0,
 806                                                    client_timeout_resend,
 807                                                    client);
 808                         if (r < 0)
 809                                 goto error;
 810
 811                         r = sd_event_source_set_priority(client->timeout_resend,
 812                                                          client->event_priority);
 813                         if (r < 0)
 814                                 goto error;
 815                 }
 816
 817                 break;
 818
 819         case DHCP_STATE_REQUESTING:
 820         case DHCP_STATE_RENEWING:
 821         case DHCP_STATE_REBINDING:
 822
 823                 r = client_handle_ack(client, message, len);
 824
 825                 if (r == DHCP_EVENT_NO_LEASE)
 826                         goto error;
 827
 828                 if (r >= 0) {
 829                         client->timeout_resend =
 830                                 sd_event_source_unref(client->timeout_resend);
 831
 832                         if (client->state == DHCP_STATE_REQUESTING)
 833                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 834                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 835                                 notify_event = r;
 836
 837                         client->state = DHCP_STATE_BOUND;
 838                         client->attempt = 1;
 839
 840                         client->last_addr = client->lease->address;
 841
 842                         r = client_set_lease_timeouts(client, time_now);
 843                         if (r < 0)
 844                                 goto error;
 845
 846                         if (notify_event)
 847                                 client_notify(client, notify_event);
 848
 849                         client->receive_message =
 850                                 sd_event_source_unref(client->receive_message);
 851                         close_nointr_nofail(client->fd);
 852                         client->fd = -1;
 853                 }
 854
 855                 r = 0;
 856
 857                 break;
 858
 859         case DHCP_STATE_INIT:
 860         case DHCP_STATE_INIT_REBOOT:
 861         case DHCP_STATE_REBOOTING:
 862         case DHCP_STATE_BOUND:
 863
 864                 break;
 865         }
 866
 867 error:
 868         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 869                 return client_stop(client, r);
 870
 871         return 0;
 872 }
 873
 874 static int client_receive_message_udp(sd_event_source *s, int fd,
 875                                       uint32_t revents, void *userdata) {
 876         sd_dhcp_client *client = userdata;
 877         _cleanup_free_ DHCPMessage *message = NULL;
 878         int buflen = 0, len, r;
 879         usec_t time_now;
 880
 881         assert(s);
 882         assert(client);
 883         assert(client->event);
 884
 885         r = ioctl(fd, FIONREAD, &buflen);
 886         if (r < 0 || buflen <= 0)
 887                 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
 888
 889         message = malloc0(buflen);
 890         if (!message)
 891                 return -ENOMEM;
 892
 893         len = read(fd, message, buflen);
 894         if (len < 0)
 895                 return 0;
 896
 897         r = sd_event_get_now_monotonic(client->event, &time_now);
 898         if (r < 0)
 899                 return client_stop(client, r);
 900
 901         return client_handle_message(client, message, len,
 902                                      time_now);
 903 }
 904
 905 static int client_receive_message_raw(sd_event_source *s, int fd,
 906                                       uint32_t revents, void *userdata) {
 907         sd_dhcp_client *client = userdata;
 908         _cleanup_free_ DHCPPacket *packet = NULL;
 909         usec_t time_now;
 910         uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
 911         struct iovec iov = {};
 912         struct msghdr msg = {
 913                 .msg_iov = &iov,
 914                 .msg_iovlen = 1,
 915                 .msg_control = cmsgbuf,
 916                 .msg_controllen = sizeof(cmsgbuf),
 917         };
 918         struct cmsghdr *cmsg;
 919         bool checksum = true;
 920         int buflen = 0, len, r;
 921
 922         assert(s);
 923         assert(client);
 924         assert(client->event);
 925
 926         r = ioctl(fd, FIONREAD, &buflen);
 927         if (r < 0 || buflen <= 0)
 928                 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
 929
 930         packet = malloc0(buflen);
 931         if (!packet)
 932                 return -ENOMEM;
 933
 934         iov.iov_base = packet;
 935         iov.iov_len = buflen;
 936
 937         len = recvmsg(fd, &msg, 0);
 938         if (len < 0) {
 939                 log_dhcp_client(client, "could not receive message from raw "
 940                                 "socket: %s", strerror(errno));
 941                 return 0;
 942         }
 943
 944         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 945                 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
 946                         struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
 947
 948                         checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
 949                         break;
 950                 }
 951         }
 952
 953         r = dhcp_packet_verify_headers(packet, len, checksum);
 954         if (r < 0)
 955                 return 0;
 956
 957         len -= DHCP_IP_UDP_SIZE;
 958
 959         r = sd_event_get_now_monotonic(client->event, &time_now);
 960         if (r < 0)
 961                 return client_stop(client, r);
 962
 963         return client_handle_message(client, &packet->dhcp, len, time_now);
 964 }
 965
 966 int sd_dhcp_client_start(sd_dhcp_client *client) {
 967         int r;
 968
 969         assert_return(client, -EINVAL);
 970         assert_return(client->event, -EINVAL);
 971         assert_return(client->index > 0, -EINVAL);
 972         assert_return(client->state == DHCP_STATE_INIT ||
 973                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 974
 975         client->xid = random_u32();
 976
 977         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 978
 979         if (r < 0) {
 980                 client_stop(client, r);
 981                 return r;
 982         }
 983
 984         client->fd = r;
 985         client->start_time = now(CLOCK_MONOTONIC);
 986         client->secs = 0;
 987
 988         log_dhcp_client(client, "STARTED");
 989
 990         return client_initialize_events(client, client_receive_message_raw,
 991                                         client->start_time);
 992 }
 993
 994 int sd_dhcp_client_stop(sd_dhcp_client *client) {
 995         return client_stop(client, DHCP_EVENT_STOP);
 996 }
 997
 998 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
 999                                 int priority) {
1000         int r;
1001
1002         assert_return(client, -EINVAL);
1003         assert_return(!client->event, -EBUSY);
1004
1005         if (event)
1006                 client->event = sd_event_ref(event);
1007         else {
1008                 r = sd_event_default(&client->event);
1009                 if (r < 0)
1010                         return 0;
1011         }
1012
1013         client->event_priority = priority;
1014
1015         return 0;
1016 }
1017
1018 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
1019         assert_return(client, -EINVAL);
1020
1021         client->event = sd_event_unref(client->event);
1022
1023         return 0;
1024 }
1025
1026 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
1027         if (!client)
1028                 return NULL;
1029
1030         return client->event;
1031 }
1032
1033 void sd_dhcp_client_free(sd_dhcp_client *client) {
1034         if (!client)
1035                 return;
1036
1037         sd_dhcp_client_stop(client);
1038         sd_dhcp_client_detach_event(client);
1039
1040         free(client->req_opts);
1041         free(client);
1042 }
1043
1044 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
1045 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
1046
1047 int sd_dhcp_client_new(sd_dhcp_client **ret) {
1048         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
1049
1050         assert_return(ret, -EINVAL);
1051
1052         client = new0(sd_dhcp_client, 1);
1053         if (!client)
1054                 return -ENOMEM;
1055
1056         client->state = DHCP_STATE_INIT;
1057         client->index = -1;
1058         client->fd = -1;
1059         client->attempt = 1;
1060
1061         client->req_opts_size = ELEMENTSOF(default_req_opts);
1062
1063         client->req_opts = memdup(default_req_opts, client->req_opts_size);
1064         if (!client->req_opts)
1065                 return -ENOMEM;
1066
1067         *ret = client;
1068         client = NULL;
1069
1070         return 0;
1071 }