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         client->fd = safe_close(client->fd);
 188
 189         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 190
 191         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 192         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 193         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 194
 195         client->attempt = 1;
 196
 197         client_notify(client, error);
 198
 199         client->start_time = 0;
 200         client->secs = 0;
 201         client->state = DHCP_STATE_INIT;
 202
 203         if (client->lease)
 204                 client->lease = sd_dhcp_lease_unref(client->lease);
 205
 206         log_dhcp_client(client, "STOPPED");
 207
 208         return 0;
 209 }
 210
 211 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
 212                                uint8_t type, uint16_t secs, uint8_t **opt,
 213                                size_t *optlen) {
 214         int r;
 215
 216         assert(secs);
 217
 218         r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
 219                               optlen);
 220         if (r < 0)
 221                 return r;
 222
 223         /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
 224            refuse to issue an DHCP lease if 'secs' is set to zero */
 225         message->secs = htobe16(secs);
 226
 227         memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
 228
 229         if (client->state == DHCP_STATE_RENEWING ||
 230             client->state == DHCP_STATE_REBINDING)
 231                 message->ciaddr = client->lease->address;
 232
 233         /* Some DHCP servers will refuse to issue an DHCP lease if the Client
 234            Identifier option is not set */
 235         r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
 236                                ETH_ALEN, &client->mac_addr);
 237         if (r < 0)
 238                 return r;
 239
 240         if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
 241                 be16_t max_size;
 242
 243                 r = dhcp_option_append(opt, optlen,
 244                                        DHCP_OPTION_PARAMETER_REQUEST_LIST,
 245                                        client->req_opts_size,
 246                                        client->req_opts);
 247                 if (r < 0)
 248                         return r;
 249
 250                 /* Some DHCP servers will send bigger DHCP packets than the
 251                    defined default size unless the Maximum Messge Size option
 252                    is explicitely set */
 253                 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
 254                                    DHCP_MIN_OPTIONS_SIZE);
 255                 r = dhcp_option_append(opt, optlen,
 256                                        DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
 257                                        2, &max_size);
 258                 if (r < 0)
 259                         return r;
 260         }
 261
 262         return 0;
 263 }
 264
 265 static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
 266                                 size_t len) {
 267         dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
 268                                       INADDR_BROADCAST, DHCP_PORT_SERVER, len);
 269
 270         return dhcp_network_send_raw_socket(client->fd, &client->link,
 271                                             packet, len);
 272 }
 273
 274 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
 275         int err = 0;
 276         _cleanup_free_ DHCPPacket *discover;
 277         size_t optlen, len;
 278         uint8_t *opt;
 279
 280         optlen = DHCP_MIN_OPTIONS_SIZE;
 281         len = sizeof(DHCPPacket) + optlen;
 282
 283         discover = malloc0(len);
 284
 285         if (!discover)
 286                 return -ENOMEM;
 287
 288         err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
 289                                   secs, &opt, &optlen);
 290         if (err < 0)
 291                 return err;
 292
 293         if (client->last_addr != INADDR_ANY) {
 294                 err = dhcp_option_append(&opt, &optlen,
 295                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 296                                          4, &client->last_addr);
 297                 if (err < 0)
 298                         return err;
 299         }
 300
 301         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 302         if (err < 0)
 303                 return err;
 304
 305         err = dhcp_client_send_raw(client, discover, len);
 306         if (err < 0)
 307                 return err;
 308
 309         log_dhcp_client(client, "DISCOVER");
 310
 311         return 0;
 312 }
 313
 314 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
 315         _cleanup_free_ DHCPPacket *request;
 316         size_t optlen, len;
 317         int err;
 318         uint8_t *opt;
 319
 320         optlen = DHCP_MIN_OPTIONS_SIZE;
 321         len = sizeof(DHCPPacket) + optlen;
 322
 323         request = malloc0(len);
 324         if (!request)
 325                 return -ENOMEM;
 326
 327         err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
 328                                   &opt, &optlen);
 329         if (err < 0)
 330                 return err;
 331
 332         if (client->state == DHCP_STATE_REQUESTING) {
 333                 err = dhcp_option_append(&opt, &optlen,
 334                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 335                                          4, &client->lease->address);
 336                 if (err < 0)
 337                         return err;
 338
 339                 err = dhcp_option_append(&opt, &optlen,
 340                                          DHCP_OPTION_SERVER_IDENTIFIER,
 341                                          4, &client->lease->server_address);
 342                 if (err < 0)
 343                         return err;
 344         }
 345
 346         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 347         if (err < 0)
 348                 return err;
 349
 350         if (client->state == DHCP_STATE_RENEWING) {
 351                 err = dhcp_network_send_udp_socket(client->fd,
 352                                                    client->lease->server_address,
 353                                                    DHCP_PORT_SERVER,
 354                                                    &request->dhcp,
 355                                                    len - DHCP_IP_UDP_SIZE);
 356         } else {
 357                 err = dhcp_client_send_raw(client, request, len);
 358         }
 359         if (err < 0)
 360                 return err;
 361
 362         log_dhcp_client(client, "REQUEST");
 363
 364         return 0;
 365 }
 366
 367 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 368 {
 369         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 370
 371         return client->secs;
 372 }
 373
 374 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 375                                  void *userdata) {
 376         sd_dhcp_client *client = userdata;
 377         usec_t next_timeout = 0;
 378         uint64_t time_now;
 379         uint32_t time_left;
 380         int r;
 381
 382         assert(s);
 383         assert(client);
 384         assert(client->event);
 385
 386         r = sd_event_get_now_monotonic(client->event, &time_now);
 387         if (r < 0)
 388                 goto error;
 389
 390         switch (client->state) {
 391         case DHCP_STATE_RENEWING:
 392
 393                 time_left = (client->lease->t2 - client->lease->t1) / 2;
 394                 if (time_left < 60)
 395                         time_left = 60;
 396
 397                 next_timeout = time_now + time_left * USEC_PER_SEC;
 398
 399                 break;
 400
 401         case DHCP_STATE_REBINDING:
 402
 403                 time_left = (client->lease->lifetime - client->lease->t2) / 2;
 404                 if (time_left < 60)
 405                         time_left = 60;
 406
 407                 next_timeout = time_now + time_left * USEC_PER_SEC;
 408                 break;
 409
 410         case DHCP_STATE_INIT:
 411         case DHCP_STATE_INIT_REBOOT:
 412         case DHCP_STATE_REBOOTING:
 413         case DHCP_STATE_SELECTING:
 414         case DHCP_STATE_REQUESTING:
 415         case DHCP_STATE_BOUND:
 416
 417                 if (client->attempt < 64)
 418                         client->attempt *= 2;
 419
 420                 next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC;
 421
 422                 break;
 423         }
 424
 425         next_timeout += (random_u32() & 0x1fffff);
 426
 427         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 428
 429         r = sd_event_add_monotonic(client->event,
 430                                      &client->timeout_resend,
 431                                      next_timeout,
 432                                      10 * USEC_PER_MSEC,
 433                                      client_timeout_resend, client);
 434         if (r < 0)
 435                 goto error;
 436
 437         r = sd_event_source_set_priority(client->timeout_resend,
 438                                          client->event_priority);
 439         if (r < 0)
 440                 goto error;
 441
 442         switch (client->state) {
 443         case DHCP_STATE_INIT:
 444
 445                 client_update_secs(client, time_now);
 446
 447                 r = client_send_discover(client, client->secs);
 448                 if (r >= 0) {
 449                         client->state = DHCP_STATE_SELECTING;
 450                         client->attempt = 1;
 451                 } else {
 452                         if (client->attempt >= 64)
 453                                 goto error;
 454                 }
 455
 456                 break;
 457
 458         case DHCP_STATE_SELECTING:
 459                 client_update_secs(client, time_now);
 460
 461                 r = client_send_discover(client, client->secs);
 462                 if (r < 0 && client->attempt >= 64)
 463                         goto error;
 464
 465                 break;
 466
 467         case DHCP_STATE_REQUESTING:
 468         case DHCP_STATE_RENEWING:
 469         case DHCP_STATE_REBINDING:
 470                 r = client_send_request(client, client->secs);
 471                 if (r < 0 && client->attempt >= 64)
 472                          goto error;
 473
 474                 client->request_sent = time_now;
 475
 476                 break;
 477
 478         case DHCP_STATE_INIT_REBOOT:
 479         case DHCP_STATE_REBOOTING:
 480         case DHCP_STATE_BOUND:
 481
 482                 break;
 483         }
 484
 485         return 0;
 486
 487 error:
 488         client_stop(client, r);
 489
 490         /* Errors were dealt with when stopping the client, don't spill
 491            errors into the event loop handler */
 492         return 0;
 493 }
 494
 495 static int client_initialize_events(sd_dhcp_client *client,
 496                                     sd_event_io_handler_t io_callback) {
 497         int r;
 498
 499         assert(client);
 500         assert(client->event);
 501
 502         r = sd_event_add_io(client->event, &client->receive_message,
 503                             client->fd, EPOLLIN, io_callback,
 504                             client);
 505         if (r < 0)
 506                 goto error;
 507
 508         r = sd_event_source_set_priority(client->receive_message,
 509                                          client->event_priority);
 510         if (r < 0)
 511                 goto error;
 512
 513         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 514
 515         r = sd_event_add_monotonic(client->event,
 516                                    &client->timeout_resend, 0, 0,
 517                                    client_timeout_resend, client);
 518         if (r < 0)
 519                 goto error;
 520
 521         r = sd_event_source_set_priority(client->timeout_resend,
 522                                          client->event_priority);
 523
 524 error:
 525         if (r < 0)
 526                 client_stop(client, r);
 527
 528         return 0;
 529
 530 }
 531
 532 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 533                                  void *userdata) {
 534         sd_dhcp_client *client = userdata;
 535
 536         log_dhcp_client(client, "EXPIRED");
 537
 538         client_stop(client, DHCP_EVENT_EXPIRED);
 539
 540         return 0;
 541 }
 542
 543 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 544         sd_dhcp_client *client = userdata;
 545         int r;
 546
 547         client->receive_message = sd_event_source_unref(client->receive_message);
 548         client->fd = safe_close(client->fd);
 549
 550         client->state = DHCP_STATE_REBINDING;
 551         client->attempt = 1;
 552
 553         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 554         if (r < 0) {
 555                 client_stop(client, r);
 556                 return 0;
 557         }
 558
 559         client->fd = r;
 560
 561         log_dhcp_client(client, "TIMEOUT T2");
 562
 563         return client_initialize_events(client, client_receive_message_raw);
 564 }
 565
 566 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 567                              void *userdata) {
 568         sd_dhcp_client *client = userdata;
 569         int r;
 570
 571         client->state = DHCP_STATE_RENEWING;
 572         client->attempt = 1;
 573
 574         r = dhcp_network_bind_udp_socket(client->index,
 575                                          client->lease->address,
 576                                          DHCP_PORT_CLIENT);
 577         if (r < 0) {
 578                 client_stop(client, r);
 579                 return 0;
 580         }
 581
 582         client->fd = r;
 583
 584         log_dhcp_client(client, "TIMEOUT T1");
 585
 586         return client_initialize_events(client, client_receive_message_udp);
 587 }
 588
 589 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 590                                size_t len) {
 591         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 592         int r;
 593
 594         r = dhcp_lease_new(&lease);
 595         if (r < 0)
 596                 return r;
 597
 598         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 599         if (r != DHCP_OFFER)
 600                 return -ENOMSG;
 601
 602         lease->next_server = offer->siaddr;
 603
 604         lease->address = offer->yiaddr;
 605
 606         if (lease->address == INADDR_ANY ||
 607             lease->server_address == INADDR_ANY ||
 608             lease->subnet_mask == INADDR_ANY ||
 609             lease->lifetime == 0)
 610                 return -ENOMSG;
 611
 612         client->lease = lease;
 613         lease = NULL;
 614
 615         log_dhcp_client(client, "OFFER");
 616
 617         return 0;
 618 }
 619
 620 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 621                              size_t len) {
 622         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 623         int r;
 624
 625         r = dhcp_lease_new(&lease);
 626         if (r < 0)
 627                 return r;
 628
 629         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 630         if (r == DHCP_NAK) {
 631                 log_dhcp_client(client, "NAK");
 632                 return DHCP_EVENT_NO_LEASE;
 633         }
 634
 635         if (r != DHCP_ACK)
 636                 return -ENOMSG;
 637
 638         lease->next_server = ack->siaddr;
 639
 640         lease->address = ack->yiaddr;
 641
 642         if (lease->address == INADDR_ANY ||
 643             lease->server_address == INADDR_ANY ||
 644             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 645                 return -ENOMSG;
 646
 647         r = DHCP_EVENT_IP_ACQUIRE;
 648         if (client->lease) {
 649                 if (client->lease->address != lease->address ||
 650                     client->lease->subnet_mask != lease->subnet_mask ||
 651                     client->lease->router != lease->router) {
 652                         r = DHCP_EVENT_IP_CHANGE;
 653                 }
 654
 655                 client->lease = sd_dhcp_lease_unref(client->lease);
 656         }
 657
 658         client->lease = lease;
 659         lease = NULL;
 660
 661         log_dhcp_client(client, "ACK");
 662
 663         return r;
 664 }
 665
 666 static uint64_t client_compute_timeout(uint64_t request_sent,
 667                                        uint32_t lifetime) {
 668         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 669                 + (random_u32() & 0x1fffff);
 670 }
 671
 672 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 673         uint64_t next_timeout;
 674         int r;
 675
 676         assert(client);
 677         assert(client->event);
 678
 679         if (client->lease->lifetime < 10)
 680                 return -EINVAL;
 681
 682         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 683         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 684         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 685
 686         if (!client->lease->t1)
 687                 client->lease->t1 = client->lease->lifetime / 2;
 688
 689         next_timeout = client_compute_timeout(client->request_sent,
 690                                               client->lease->t1);
 691         if (next_timeout < usec)
 692                 return -EINVAL;
 693
 694         r = sd_event_add_monotonic(client->event,
 695                                    &client->timeout_t1,
 696                                    next_timeout,
 697                                    10 * USEC_PER_MSEC,
 698                                    client_timeout_t1, client);
 699         if (r < 0)
 700                 return r;
 701
 702         r = sd_event_source_set_priority(client->timeout_t1,
 703                                          client->event_priority);
 704         if (r < 0)
 705                 return r;
 706
 707         if (!client->lease->t2)
 708                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 709
 710         if (client->lease->t2 < client->lease->t1)
 711                 return -EINVAL;
 712
 713         if (client->lease->lifetime < client->lease->t2)
 714                 return -EINVAL;
 715
 716         next_timeout = client_compute_timeout(client->request_sent,
 717                                               client->lease->t2);
 718         if (next_timeout < usec)
 719                 return -EINVAL;
 720
 721         r = sd_event_add_monotonic(client->event,
 722                                    &client->timeout_t2,
 723                                    next_timeout,
 724                                    10 * USEC_PER_MSEC,
 725                                    client_timeout_t2, client);
 726         if (r < 0)
 727                 return r;
 728
 729         r = sd_event_source_set_priority(client->timeout_t2,
 730                                          client->event_priority);
 731         if (r < 0)
 732                 return r;
 733
 734         next_timeout = client_compute_timeout(client->request_sent,
 735                                               client->lease->lifetime);
 736         if (next_timeout < usec)
 737                 return -EINVAL;
 738
 739         r = sd_event_add_monotonic(client->event,
 740                                    &client->timeout_expire, next_timeout,
 741                                    10 * USEC_PER_MSEC,
 742                                    client_timeout_expire, client);
 743         if (r < 0)
 744                 return r;
 745
 746         r = sd_event_source_set_priority(client->timeout_expire,
 747                                          client->event_priority);
 748         if (r < 0)
 749                 return r;
 750
 751         return 0;
 752 }
 753
 754 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 755                                  int len, usec_t time_now) {
 756         int r = 0, notify_event = 0;
 757
 758         assert(client);
 759         assert(client->event);
 760         assert(message);
 761
 762         if (len < DHCP_MESSAGE_SIZE) {
 763                 log_dhcp_client(client, "message too small (%d bytes): "
 764                                 "ignoring", len);
 765                 return 0;
 766         }
 767
 768         if (message->op != BOOTREPLY) {
 769                 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
 770                 return 0;
 771         }
 772
 773         if (be32toh(message->xid) != client->xid) {
 774                 log_dhcp_client(client, "received xid (%u) does not match "
 775                                 "expected (%u): ignoring",
 776                                 be32toh(message->xid), client->xid);
 777                 return 0;
 778         }
 779
 780         if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
 781                    ETHER_ADDR_LEN)) {
 782                 log_dhcp_client(client, "received chaddr does not match "
 783                                 "expected: ignoring");
 784                 return 0;
 785         }
 786
 787         switch (client->state) {
 788         case DHCP_STATE_SELECTING:
 789
 790                 r = client_handle_offer(client, message, len);
 791                 if (r >= 0) {
 792
 793                         client->timeout_resend =
 794                                 sd_event_source_unref(client->timeout_resend);
 795
 796                         client->state = DHCP_STATE_REQUESTING;
 797                         client->attempt = 1;
 798
 799                         r = sd_event_add_monotonic(client->event,
 800                                                    &client->timeout_resend, 0,
 801                                                    0, client_timeout_resend,
 802                                                    client);
 803                         if (r < 0)
 804                                 goto error;
 805
 806                         r = sd_event_source_set_priority(client->timeout_resend,
 807                                                          client->event_priority);
 808                         if (r < 0)
 809                                 goto error;
 810                 }
 811
 812                 break;
 813
 814         case DHCP_STATE_REQUESTING:
 815         case DHCP_STATE_RENEWING:
 816         case DHCP_STATE_REBINDING:
 817
 818                 r = client_handle_ack(client, message, len);
 819
 820                 if (r == DHCP_EVENT_NO_LEASE)
 821                         goto error;
 822
 823                 if (r >= 0) {
 824                         client->timeout_resend =
 825                                 sd_event_source_unref(client->timeout_resend);
 826
 827                         if (client->state == DHCP_STATE_REQUESTING)
 828                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 829                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 830                                 notify_event = r;
 831
 832                         client->state = DHCP_STATE_BOUND;
 833                         client->attempt = 1;
 834
 835                         client->last_addr = client->lease->address;
 836
 837                         r = client_set_lease_timeouts(client, time_now);
 838                         if (r < 0)
 839                                 goto error;
 840
 841                         if (notify_event)
 842                                 client_notify(client, notify_event);
 843
 844                         client->receive_message =
 845                                 sd_event_source_unref(client->receive_message);
 846                         client->fd = safe_close(client->fd);
 847                 }
 848
 849                 r = 0;
 850
 851                 break;
 852
 853         case DHCP_STATE_INIT:
 854         case DHCP_STATE_INIT_REBOOT:
 855         case DHCP_STATE_REBOOTING:
 856         case DHCP_STATE_BOUND:
 857
 858                 break;
 859         }
 860
 861 error:
 862         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 863                 return client_stop(client, r);
 864
 865         return 0;
 866 }
 867
 868 static int client_receive_message_udp(sd_event_source *s, int fd,
 869                                       uint32_t revents, void *userdata) {
 870         sd_dhcp_client *client = userdata;
 871         _cleanup_free_ DHCPMessage *message = NULL;
 872         int buflen = 0, len, r;
 873         usec_t time_now;
 874
 875         assert(s);
 876         assert(client);
 877         assert(client->event);
 878
 879         r = ioctl(fd, FIONREAD, &buflen);
 880         if (r < 0 || buflen <= 0)
 881                 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
 882
 883         message = malloc0(buflen);
 884         if (!message)
 885                 return -ENOMEM;
 886
 887         len = read(fd, message, buflen);
 888         if (len < 0)
 889                 return 0;
 890
 891         r = sd_event_get_now_monotonic(client->event, &time_now);
 892         if (r < 0)
 893                 return client_stop(client, r);
 894
 895         return client_handle_message(client, message, len,
 896                                      time_now);
 897 }
 898
 899 static int client_receive_message_raw(sd_event_source *s, int fd,
 900                                       uint32_t revents, void *userdata) {
 901         sd_dhcp_client *client = userdata;
 902         _cleanup_free_ DHCPPacket *packet = NULL;
 903         usec_t time_now;
 904         uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
 905         struct iovec iov = {};
 906         struct msghdr msg = {
 907                 .msg_iov = &iov,
 908                 .msg_iovlen = 1,
 909                 .msg_control = cmsgbuf,
 910                 .msg_controllen = sizeof(cmsgbuf),
 911         };
 912         struct cmsghdr *cmsg;
 913         bool checksum = true;
 914         int buflen = 0, len, r;
 915
 916         assert(s);
 917         assert(client);
 918         assert(client->event);
 919
 920         r = ioctl(fd, FIONREAD, &buflen);
 921         if (r < 0 || buflen <= 0)
 922                 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
 923
 924         packet = malloc0(buflen);
 925         if (!packet)
 926                 return -ENOMEM;
 927
 928         iov.iov_base = packet;
 929         iov.iov_len = buflen;
 930
 931         len = recvmsg(fd, &msg, 0);
 932         if (len < 0) {
 933                 log_dhcp_client(client, "could not receive message from raw "
 934                                 "socket: %s", strerror(errno));
 935                 return 0;
 936         }
 937
 938         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
 939                 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
 940                         struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
 941
 942                         checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
 943                         break;
 944                 }
 945         }
 946
 947         r = dhcp_packet_verify_headers(packet, len, checksum);
 948         if (r < 0)
 949                 return 0;
 950
 951         len -= DHCP_IP_UDP_SIZE;
 952
 953         r = sd_event_get_now_monotonic(client->event, &time_now);
 954         if (r < 0)
 955                 return client_stop(client, r);
 956
 957         return client_handle_message(client, &packet->dhcp, len, time_now);
 958 }
 959
 960 int sd_dhcp_client_start(sd_dhcp_client *client) {
 961         int r;
 962
 963         assert_return(client, -EINVAL);
 964         assert_return(client->event, -EINVAL);
 965         assert_return(client->index > 0, -EINVAL);
 966         assert_return(client->state == DHCP_STATE_INIT ||
 967                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 968
 969         client->xid = random_u32();
 970
 971         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 972
 973         if (r < 0) {
 974                 client_stop(client, r);
 975                 return r;
 976         }
 977
 978         client->fd = r;
 979         client->start_time = now(CLOCK_MONOTONIC);
 980         client->secs = 0;
 981
 982         log_dhcp_client(client, "STARTED");
 983
 984         return client_initialize_events(client, client_receive_message_raw);
 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 }