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(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 client_send_discover(sd_dhcp_client *client, uint16_t secs) {
 268         int err = 0;
 269         _cleanup_free_ DHCPPacket *discover;
 270         size_t optlen, len;
 271         uint8_t *opt;
 272
 273         optlen = DHCP_MIN_OPTIONS_SIZE;
 274         len = sizeof(DHCPPacket) + optlen;
 275
 276         discover = malloc0(len);
 277
 278         if (!discover)
 279                 return -ENOMEM;
 280
 281         err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
 282                                   secs, &opt, &optlen);
 283         if (err < 0)
 284                 return err;
 285
 286         if (client->last_addr != INADDR_ANY) {
 287                 err = dhcp_option_append(&opt, &optlen,
 288                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 289                                          4, &client->last_addr);
 290                 if (err < 0)
 291                         return err;
 292         }
 293
 294         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 295         if (err < 0)
 296                 return err;
 297
 298         dhcp_packet_append_ip_headers(discover, len);
 299
 300         err = dhcp_network_send_raw_socket(client->fd, &client->link,
 301                                            discover, len);
 302
 303         log_dhcp_client(client, "DISCOVER");
 304
 305         return err;
 306 }
 307
 308 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
 309         _cleanup_free_ DHCPPacket *request;
 310         size_t optlen, len;
 311         int err;
 312         uint8_t *opt;
 313
 314         optlen = DHCP_MIN_OPTIONS_SIZE;
 315         len = sizeof(DHCPPacket) + optlen;
 316
 317         request = malloc0(len);
 318         if (!request)
 319                 return -ENOMEM;
 320
 321         err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
 322                                   &opt, &optlen);
 323         if (err < 0)
 324                 return err;
 325
 326         if (client->state == DHCP_STATE_REQUESTING) {
 327                 err = dhcp_option_append(&opt, &optlen,
 328                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 329                                          4, &client->lease->address);
 330                 if (err < 0)
 331                         return err;
 332
 333                 err = dhcp_option_append(&opt, &optlen,
 334                                          DHCP_OPTION_SERVER_IDENTIFIER,
 335                                          4, &client->lease->server_address);
 336                 if (err < 0)
 337                         return err;
 338         }
 339
 340         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 341         if (err < 0)
 342                 return err;
 343
 344         if (client->state == DHCP_STATE_RENEWING) {
 345                 err = dhcp_network_send_udp_socket(client->fd,
 346                                                    client->lease->server_address,
 347                                                    DHCP_PORT_SERVER,
 348                                                    &request->dhcp,
 349                                                    len - DHCP_IP_UDP_SIZE);
 350         } else {
 351                 dhcp_packet_append_ip_headers(request, len);
 352
 353                 err = dhcp_network_send_raw_socket(client->fd, &client->link,
 354                                                    request, len);
 355         }
 356
 357         log_dhcp_client(client, "REQUEST");
 358
 359         return err;
 360 }
 361
 362 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 363 {
 364         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 365
 366         return client->secs;
 367 }
 368
 369 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 370                                  void *userdata) {
 371         sd_dhcp_client *client = userdata;
 372         usec_t next_timeout = 0;
 373         uint32_t time_left;
 374         int r = 0;
 375
 376         assert(s);
 377         assert(client);
 378         assert(client->event);
 379
 380         switch (client->state) {
 381         case DHCP_STATE_RENEWING:
 382
 383                 time_left = (client->lease->t2 - client->lease->t1) / 2;
 384                 if (time_left < 60)
 385                         time_left = 60;
 386
 387                 next_timeout = usec + time_left * USEC_PER_SEC;
 388
 389                 break;
 390
 391         case DHCP_STATE_REBINDING:
 392
 393                 time_left = (client->lease->lifetime - client->lease->t2) / 2;
 394                 if (time_left < 60)
 395                         time_left = 60;
 396
 397                 next_timeout = usec + time_left * USEC_PER_SEC;
 398                 break;
 399
 400         case DHCP_STATE_INIT:
 401         case DHCP_STATE_INIT_REBOOT:
 402         case DHCP_STATE_REBOOTING:
 403         case DHCP_STATE_SELECTING:
 404         case DHCP_STATE_REQUESTING:
 405         case DHCP_STATE_BOUND:
 406
 407                 if (client->attempt < 64)
 408                         client->attempt *= 2;
 409
 410                 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
 411
 412                 break;
 413         }
 414
 415         next_timeout += (random_u32() & 0x1fffff);
 416
 417         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 418
 419         r = sd_event_add_monotonic(client->event,
 420                                      &client->timeout_resend,
 421                                      next_timeout,
 422                                      10 * USEC_PER_MSEC,
 423                                      client_timeout_resend, client);
 424         if (r < 0)
 425                 goto error;
 426
 427         r = sd_event_source_set_priority(client->timeout_resend,
 428                                          client->event_priority);
 429         if (r < 0)
 430                 goto error;
 431
 432         switch (client->state) {
 433         case DHCP_STATE_INIT:
 434
 435                 client_update_secs(client, usec);
 436
 437                 r = client_send_discover(client, client->secs);
 438                 if (r >= 0) {
 439                         client->state = DHCP_STATE_SELECTING;
 440                         client->attempt = 1;
 441                 } else {
 442                         if (client->attempt >= 64)
 443                                 goto error;
 444                 }
 445
 446                 break;
 447
 448         case DHCP_STATE_SELECTING:
 449                 client_update_secs(client, usec);
 450
 451                 r = client_send_discover(client, client->secs);
 452                 if (r < 0 && client->attempt >= 64)
 453                         goto error;
 454
 455                 break;
 456
 457         case DHCP_STATE_REQUESTING:
 458         case DHCP_STATE_RENEWING:
 459         case DHCP_STATE_REBINDING:
 460                 r = client_send_request(client, client->secs);
 461                 if (r < 0 && client->attempt >= 64)
 462                          goto error;
 463
 464                 client->request_sent = usec;
 465
 466                 break;
 467
 468         case DHCP_STATE_INIT_REBOOT:
 469         case DHCP_STATE_REBOOTING:
 470         case DHCP_STATE_BOUND:
 471
 472                 break;
 473         }
 474
 475         return 0;
 476
 477 error:
 478         client_stop(client, r);
 479
 480         /* Errors were dealt with when stopping the client, don't spill
 481            errors into the event loop handler */
 482         return 0;
 483 }
 484
 485 static int client_initialize_events(sd_dhcp_client *client,
 486                                     sd_event_io_handler_t io_callback,
 487                                     usec_t usec) {
 488         int r;
 489
 490         assert(client);
 491         assert(client->event);
 492
 493         r = sd_event_add_io(client->event, &client->receive_message,
 494                             client->fd, EPOLLIN, io_callback,
 495                             client);
 496         if (r < 0)
 497                 goto error;
 498
 499         r = sd_event_source_set_priority(client->receive_message,
 500                                          client->event_priority);
 501         if (r < 0)
 502                 goto error;
 503
 504         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 505
 506         r = sd_event_add_monotonic(client->event,
 507                                    &client->timeout_resend,
 508                                    usec, 0,
 509                                    client_timeout_resend, client);
 510         if (r < 0)
 511                 goto error;
 512
 513         r = sd_event_source_set_priority(client->timeout_resend,
 514                                          client->event_priority);
 515
 516 error:
 517         if (r < 0)
 518                 client_stop(client, r);
 519
 520         return 0;
 521
 522 }
 523
 524 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 525                                  void *userdata) {
 526         sd_dhcp_client *client = userdata;
 527
 528         log_dhcp_client(client, "EXPIRED");
 529
 530         client_stop(client, DHCP_EVENT_EXPIRED);
 531
 532         return 0;
 533 }
 534
 535 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 536         sd_dhcp_client *client = userdata;
 537         int r;
 538
 539         if (client->fd >= 0) {
 540                 client->receive_message =
 541                         sd_event_source_unref(client->receive_message);
 542                 close(client->fd);
 543                 client->fd = -1;
 544         }
 545
 546         client->state = DHCP_STATE_REBINDING;
 547         client->attempt = 1;
 548
 549         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 550         if (r < 0) {
 551                 client_stop(client, r);
 552                 return 0;
 553         }
 554
 555         client->fd = r;
 556
 557         log_dhcp_client(client, "TIMEOUT T2");
 558
 559         return client_initialize_events(client, client_receive_message_raw,
 560                                         usec);
 561 }
 562
 563 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 564                              void *userdata) {
 565         sd_dhcp_client *client = userdata;
 566         int r;
 567
 568         client->state = DHCP_STATE_RENEWING;
 569         client->attempt = 1;
 570
 571         r = dhcp_network_bind_udp_socket(client->index,
 572                                          client->lease->address,
 573                                          DHCP_PORT_CLIENT);
 574         if (r < 0) {
 575                 client_stop(client, r);
 576                 return 0;
 577         }
 578
 579         client->fd = r;
 580
 581         log_dhcp_client(client, "TIMEOUT T1");
 582
 583         return client_initialize_events(client, client_receive_message_udp, usec);
 584 }
 585
 586 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 587                                size_t len) {
 588         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 589         int r;
 590
 591         r = dhcp_lease_new(&lease);
 592         if (r < 0)
 593                 return r;
 594
 595         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 596         if (r != DHCP_OFFER)
 597                 return -ENOMSG;
 598
 599         lease->next_server = offer->siaddr;
 600
 601         lease->address = offer->yiaddr;
 602
 603         if (lease->address == INADDR_ANY ||
 604             lease->server_address == INADDR_ANY ||
 605             lease->subnet_mask == INADDR_ANY ||
 606             lease->lifetime == 0)
 607                 return -ENOMSG;
 608
 609         client->lease = lease;
 610         lease = NULL;
 611
 612         log_dhcp_client(client, "OFFER");
 613
 614         return 0;
 615 }
 616
 617 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 618                              size_t len) {
 619         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 620         int r;
 621
 622         r = dhcp_lease_new(&lease);
 623         if (r < 0)
 624                 return r;
 625
 626         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 627         if (r == DHCP_NAK) {
 628                 log_dhcp_client(client, "NAK");
 629                 return DHCP_EVENT_NO_LEASE;
 630         }
 631
 632         if (r != DHCP_ACK)
 633                 return -ENOMSG;
 634
 635         lease->next_server = ack->siaddr;
 636
 637         lease->address = ack->yiaddr;
 638
 639         if (lease->address == INADDR_ANY ||
 640             lease->server_address == INADDR_ANY ||
 641             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 642                 return -ENOMSG;
 643
 644         r = DHCP_EVENT_IP_ACQUIRE;
 645         if (client->lease) {
 646                 if (client->lease->address != lease->address ||
 647                     client->lease->subnet_mask != lease->subnet_mask ||
 648                     client->lease->router != lease->router) {
 649                         r = DHCP_EVENT_IP_CHANGE;
 650                 }
 651
 652                 client->lease = sd_dhcp_lease_unref(client->lease);
 653         }
 654
 655         client->lease = lease;
 656         lease = NULL;
 657
 658         log_dhcp_client(client, "ACK");
 659
 660         return r;
 661 }
 662
 663 static uint64_t client_compute_timeout(uint64_t request_sent,
 664                                        uint32_t lifetime) {
 665         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 666                 + (random_u32() & 0x1fffff);
 667 }
 668
 669 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 670         uint64_t next_timeout;
 671         int r;
 672
 673         assert(client);
 674         assert(client->event);
 675
 676         if (client->lease->lifetime < 10)
 677                 return -EINVAL;
 678
 679         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 680         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 681         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 682
 683         if (!client->lease->t1)
 684                 client->lease->t1 = client->lease->lifetime / 2;
 685
 686         next_timeout = client_compute_timeout(client->request_sent,
 687                                               client->lease->t1);
 688         if (next_timeout < usec)
 689                 return -EINVAL;
 690
 691         r = sd_event_add_monotonic(client->event,
 692                                      &client->timeout_t1,
 693                                      next_timeout,
 694                                      10 * USEC_PER_MSEC,
 695                                      client_timeout_t1, client);
 696         if (r < 0)
 697                 return r;
 698
 699         r = sd_event_source_set_priority(client->timeout_t1,
 700                                          client->event_priority);
 701         if (r < 0)
 702                 return r;
 703
 704         if (!client->lease->t2)
 705                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 706
 707         if (client->lease->t2 < client->lease->t1)
 708                 return -EINVAL;
 709
 710         if (client->lease->lifetime < client->lease->t2)
 711                 return -EINVAL;
 712
 713         next_timeout = client_compute_timeout(client->request_sent,
 714                                               client->lease->t2);
 715         if (next_timeout < usec)
 716                 return -EINVAL;
 717
 718         r = sd_event_add_monotonic(client->event,
 719                                      &client->timeout_t2,
 720                                      next_timeout,
 721                                      10 * USEC_PER_MSEC,
 722                                      client_timeout_t2, client);
 723         if (r < 0)
 724                 return r;
 725
 726         r = sd_event_source_set_priority(client->timeout_t2,
 727                                          client->event_priority);
 728         if (r < 0)
 729                 return r;
 730
 731         next_timeout = client_compute_timeout(client->request_sent,
 732                                               client->lease->lifetime);
 733         if (next_timeout < usec)
 734                 return -EINVAL;
 735
 736         r = sd_event_add_monotonic(client->event,
 737                                      &client->timeout_expire, next_timeout,
 738                                      10 * USEC_PER_MSEC,
 739                                      client_timeout_expire, client);
 740         if (r < 0)
 741                 return r;
 742
 743         r = sd_event_source_set_priority(client->timeout_expire,
 744                                          client->event_priority);
 745         if (r < 0)
 746                 return r;
 747
 748         return 0;
 749 }
 750
 751 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 752                                  int len, usec_t time_now) {
 753         int r = 0, notify_event = 0;
 754
 755         assert(client);
 756         assert(client->event);
 757         assert(message);
 758
 759         if (len < DHCP_MESSAGE_SIZE) {
 760                 log_dhcp_client(client, "message too small (%d bytes): "
 761                                 "ignoring", len);
 762                 return 0;
 763         }
 764
 765         if (message->op != BOOTREPLY) {
 766                 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
 767                 return 0;
 768         }
 769
 770         if (be32toh(message->xid) != client->xid) {
 771                 log_dhcp_client(client, "received xid (%u) does not match "
 772                                 "expected (%u): ignoring",
 773                                 be32toh(message->xid), client->xid);
 774                 return 0;
 775         }
 776
 777         if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
 778                    ETHER_ADDR_LEN)) {
 779                 log_dhcp_client(client, "received chaddr does not match "
 780                                 "expected: ignoring");
 781                 return 0;
 782         }
 783
 784         switch (client->state) {
 785         case DHCP_STATE_SELECTING:
 786
 787                 r = client_handle_offer(client, message, len);
 788                 if (r >= 0) {
 789
 790                         client->timeout_resend =
 791                                 sd_event_source_unref(client->timeout_resend);
 792
 793                         client->state = DHCP_STATE_REQUESTING;
 794                         client->attempt = 1;
 795
 796                         r = sd_event_add_monotonic(client->event,
 797                                                    &client->timeout_resend,
 798                                                    time_now, 0,
 799                                                    client_timeout_resend,
 800                                                    client);
 801                         if (r < 0)
 802                                 goto error;
 803
 804                         r = sd_event_source_set_priority(client->timeout_resend,
 805                                                          client->event_priority);
 806                         if (r < 0)
 807                                 goto error;
 808                 }
 809
 810                 break;
 811
 812         case DHCP_STATE_REQUESTING:
 813         case DHCP_STATE_RENEWING:
 814         case DHCP_STATE_REBINDING:
 815
 816                 r = client_handle_ack(client, message, len);
 817
 818                 if (r == DHCP_EVENT_NO_LEASE)
 819                         goto error;
 820
 821                 if (r >= 0) {
 822                         client->timeout_resend =
 823                                 sd_event_source_unref(client->timeout_resend);
 824
 825                         if (client->state == DHCP_STATE_REQUESTING)
 826                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 827                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 828                                 notify_event = r;
 829
 830                         client->state = DHCP_STATE_BOUND;
 831                         client->attempt = 1;
 832
 833                         client->last_addr = client->lease->address;
 834
 835                         r = client_set_lease_timeouts(client, time_now);
 836                         if (r < 0)
 837                                 goto error;
 838
 839                         if (notify_event)
 840                                 client_notify(client, notify_event);
 841
 842                         client->receive_message =
 843                                 sd_event_source_unref(client->receive_message);
 844                         close(client->fd);
 845                         client->fd = -1;
 846                 }
 847
 848                 r = 0;
 849
 850                 break;
 851
 852         case DHCP_STATE_INIT:
 853         case DHCP_STATE_INIT_REBOOT:
 854         case DHCP_STATE_REBOOTING:
 855         case DHCP_STATE_BOUND:
 856
 857                 break;
 858         }
 859
 860 error:
 861         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 862                 return client_stop(client, r);
 863
 864         return 0;
 865 }
 866
 867 static int client_receive_message_udp(sd_event_source *s, int fd,
 868                                       uint32_t revents, void *userdata) {
 869         sd_dhcp_client *client = userdata;
 870         _cleanup_free_ DHCPMessage *message = NULL;
 871         int buflen = 0, len, r;
 872         usec_t time_now;
 873
 874         assert(s);
 875         assert(client);
 876         assert(client->event);
 877
 878         r = ioctl(fd, FIONREAD, &buflen);
 879         if (r < 0 || buflen <= 0)
 880                 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
 881
 882         message = malloc0(buflen);
 883         if (!message)
 884                 return -ENOMEM;
 885
 886         len = read(fd, message, buflen);
 887         if (len < 0)
 888                 return 0;
 889
 890         r = sd_event_get_now_monotonic(client->event, &time_now);
 891         if (r < 0)
 892                 return client_stop(client, r);
 893
 894         return client_handle_message(client, message, len,
 895                                      time_now);
 896 }
 897
 898 static int client_receive_message_raw(sd_event_source *s, int fd,
 899                                       uint32_t revents, void *userdata) {
 900         sd_dhcp_client *client = userdata;
 901         _cleanup_free_ DHCPPacket *packet = NULL;
 902         usec_t time_now;
 903         uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
 904         struct iovec iov = {};
 905         struct msghdr msg = {
 906                 .msg_iov = &iov,
 907                 .msg_iovlen = 1,
 908                 .msg_control = cmsgbuf,
 909                 .msg_controllen = sizeof(cmsgbuf),
 910         };
 911         struct cmsghdr *cmsg;
 912         bool checksum = true;
 913         int buflen = 0, len, r;
 914
 915         assert(s);
 916         assert(client);
 917         assert(client->event);
 918
 919         r = ioctl(fd, FIONREAD, &buflen);
 920         if (r < 0 || buflen <= 0)
 921                 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
 922
 923         packet = malloc0(buflen);
 924         if (!packet)
 925                 return -ENOMEM;
 926
 927         iov.iov_base = packet;
 928         iov.iov_len = buflen;
 929
 930         len = recvmsg(fd, &msg, 0);
 931         if (len < 0) {
 932                 log_dhcp_client(client, "could not receive message from raw "
 933                                 "socket: %s", strerror(errno));
 934                 return 0;
 935         }
 936
 937         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 938                 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
 939                         struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
 940
 941                         checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
 942                         break;
 943                 }
 944         }
 945
 946         r = dhcp_packet_verify_headers(packet, len, checksum);
 947         if (r < 0)
 948                 return 0;
 949
 950         len -= DHCP_IP_UDP_SIZE;
 951
 952         r = sd_event_get_now_monotonic(client->event, &time_now);
 953         if (r < 0)
 954                 return client_stop(client, r);
 955
 956         return client_handle_message(client, &packet->dhcp, len, time_now);
 957 }
 958
 959 int sd_dhcp_client_start(sd_dhcp_client *client) {
 960         int r;
 961
 962         assert_return(client, -EINVAL);
 963         assert_return(client->event, -EINVAL);
 964         assert_return(client->index > 0, -EINVAL);
 965         assert_return(client->state == DHCP_STATE_INIT ||
 966                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 967
 968         client->xid = random_u32();
 969
 970         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 971
 972         if (r < 0) {
 973                 client_stop(client, r);
 974                 return r;
 975         }
 976
 977         client->fd = r;
 978         client->start_time = now(CLOCK_MONOTONIC);
 979         client->secs = 0;
 980
 981         log_dhcp_client(client, "STARTED");
 982
 983         return client_initialize_events(client, client_receive_message_raw,
 984                                         client->start_time);
 985 }
 986
 987 int sd_dhcp_client_stop(sd_dhcp_client *client) {
 988         return client_stop(client, DHCP_EVENT_STOP);
 989 }
 990
 991 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
 992                                 int priority) {
 993         int r;
 994
 995         assert_return(client, -EINVAL);
 996         assert_return(!client->event, -EBUSY);
 997
 998         if (event)
 999                 client->event = sd_event_ref(event);
1000         else {
1001                 r = sd_event_default(&client->event);
1002                 if (r < 0)
1003                         return 0;
1004         }
1005
1006         client->event_priority = priority;
1007
1008         return 0;
1009 }
1010
1011 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
1012         assert_return(client, -EINVAL);
1013
1014         client->event = sd_event_unref(client->event);
1015
1016         return 0;
1017 }
1018
1019 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
1020         if (!client)
1021                 return NULL;
1022
1023         return client->event;
1024 }
1025
1026 void sd_dhcp_client_free(sd_dhcp_client *client) {
1027         if (!client)
1028                 return;
1029
1030         sd_dhcp_client_stop(client);
1031         sd_dhcp_client_detach_event(client);
1032
1033         free(client->req_opts);
1034         free(client);
1035 }
1036
1037 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
1038 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
1039
1040 int sd_dhcp_client_new(sd_dhcp_client **ret) {
1041         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
1042
1043         assert_return(ret, -EINVAL);
1044
1045         client = new0(sd_dhcp_client, 1);
1046         if (!client)
1047                 return -ENOMEM;
1048
1049         client->state = DHCP_STATE_INIT;
1050         client->index = -1;
1051         client->fd = -1;
1052         client->attempt = 1;
1053
1054         client->req_opts_size = ELEMENTSOF(default_req_opts);
1055
1056         client->req_opts = memdup(default_req_opts, client->req_opts_size);
1057         if (!client->req_opts)
1058                 return -ENOMEM;
1059
1060         *ret = client;
1061         client = NULL;
1062
1063         return 0;
1064 }