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 {
  50                 uint8_t type;
  51                 struct ether_addr mac_addr;
  52         } _packed_ client_id;
  53         uint32_t xid;
  54         usec_t start_time;
  55         uint16_t secs;
  56         unsigned int attempt;
  57         usec_t request_sent;
  58         sd_event_source *timeout_t1;
  59         sd_event_source *timeout_t2;
  60         sd_event_source *timeout_expire;
  61         sd_dhcp_client_cb_t cb;
  62         void *userdata;
  63         sd_dhcp_lease *lease;
  64 };
  65
  66 static const uint8_t default_req_opts[] = {
  67         DHCP_OPTION_SUBNET_MASK,
  68         DHCP_OPTION_ROUTER,
  69         DHCP_OPTION_HOST_NAME,
  70         DHCP_OPTION_DOMAIN_NAME,
  71         DHCP_OPTION_DOMAIN_NAME_SERVER,
  72         DHCP_OPTION_NTP_SERVER,
  73 };
  74
  75 static int client_receive_message_raw(sd_event_source *s, int fd,
  76                                       uint32_t revents, void *userdata);
  77 static int client_receive_message_udp(sd_event_source *s, int fd,
  78                                       uint32_t revents, void *userdata);
  79
  80 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
  81                                 void *userdata) {
  82         assert_return(client, -EINVAL);
  83
  84         client->cb = cb;
  85         client->userdata = userdata;
  86
  87         return 0;
  88 }
  89
  90 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
  91         size_t i;
  92
  93         assert_return(client, -EINVAL);
  94         assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
  95
  96         switch(option) {
  97         case DHCP_OPTION_PAD:
  98         case DHCP_OPTION_OVERLOAD:
  99         case DHCP_OPTION_MESSAGE_TYPE:
 100         case DHCP_OPTION_PARAMETER_REQUEST_LIST:
 101         case DHCP_OPTION_END:
 102                 return -EINVAL;
 103
 104         default:
 105                 break;
 106         }
 107
 108         for (i = 0; i < client->req_opts_size; i++)
 109                 if (client->req_opts[i] == option)
 110                         return -EEXIST;
 111
 112         if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
 113                             client->req_opts_size + 1))
 114                 return -ENOMEM;
 115
 116         client->req_opts[client->req_opts_size++] = option;
 117
 118         return 0;
 119 }
 120
 121 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
 122                                        const struct in_addr *last_addr) {
 123         assert_return(client, -EINVAL);
 124         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 125
 126         if (last_addr)
 127                 client->last_addr = last_addr->s_addr;
 128         else
 129                 client->last_addr = INADDR_ANY;
 130
 131         return 0;
 132 }
 133
 134 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
 135         assert_return(client, -EINVAL);
 136         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 137         assert_return(interface_index >= -1, -EINVAL);
 138
 139         client->index = interface_index;
 140
 141         return 0;
 142 }
 143
 144 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
 145                            const struct ether_addr *addr) {
 146         assert_return(client, -EINVAL);
 147         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 148
 149         log_dhcp_client(client, "set MAC address to "
 150                         "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
 151                         addr->ether_addr_octet[0],
 152                         addr->ether_addr_octet[1],
 153                         addr->ether_addr_octet[2],
 154                         addr->ether_addr_octet[3],
 155                         addr->ether_addr_octet[4],
 156                         addr->ether_addr_octet[5]);
 157
 158         memcpy(&client->client_id.mac_addr, addr, ETH_ALEN);
 159         client->client_id.type = 0x01;
 160
 161         return 0;
 162 }
 163
 164 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
 165         assert_return(client, -EINVAL);
 166         assert_return(ret, -EINVAL);
 167
 168         if (client->state != DHCP_STATE_BOUND &&
 169             client->state != DHCP_STATE_RENEWING &&
 170             client->state != DHCP_STATE_REBINDING)
 171                 return -EADDRNOTAVAIL;
 172
 173         *ret = sd_dhcp_lease_ref(client->lease);
 174
 175         return 0;
 176 }
 177
 178 static int client_notify(sd_dhcp_client *client, int event) {
 179         if (client->cb)
 180                 client->cb(client, event, client->userdata);
 181
 182         return 0;
 183 }
 184
 185 static int client_initialize(sd_dhcp_client *client) {
 186         assert_return(client, -EINVAL);
 187
 188         client->receive_message =
 189                 sd_event_source_unref(client->receive_message);
 190
 191         client->fd = safe_close(client->fd);
 192
 193         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 194
 195         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 196         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 197         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 198
 199         client->attempt = 1;
 200
 201         client->start_time = 0;
 202         client->secs = 0;
 203         client->state = DHCP_STATE_INIT;
 204         client->xid = 0;
 205
 206         if (client->lease)
 207                 client->lease = sd_dhcp_lease_unref(client->lease);
 208
 209         return 0;
 210 }
 211
 212 static int client_stop(sd_dhcp_client *client, int error) {
 213         assert_return(client, -EINVAL);
 214
 215         client_notify(client, error);
 216
 217         client_initialize(client);
 218
 219         log_dhcp_client(client, "STOPPED");
 220
 221         return 0;
 222 }
 223
 224 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
 225                                uint8_t type, uint16_t secs, uint8_t **opt,
 226                                size_t *optlen) {
 227         int r;
 228
 229         assert(secs);
 230
 231         r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
 232                               optlen);
 233         if (r < 0)
 234                 return r;
 235
 236         /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
 237            refuse to issue an DHCP lease if 'secs' is set to zero */
 238         message->secs = htobe16(secs);
 239
 240         memcpy(&message->chaddr, &client->client_id.mac_addr, ETH_ALEN);
 241
 242         if (client->state == DHCP_STATE_RENEWING ||
 243             client->state == DHCP_STATE_REBINDING)
 244                 message->ciaddr = client->lease->address;
 245
 246         /* Some DHCP servers will refuse to issue an DHCP lease if the Client
 247            Identifier option is not set */
 248         r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
 249                                sizeof(client->client_id), &client->client_id);
 250         if (r < 0)
 251                 return r;
 252
 253         if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
 254                 be16_t max_size;
 255
 256                 r = dhcp_option_append(opt, optlen,
 257                                        DHCP_OPTION_PARAMETER_REQUEST_LIST,
 258                                        client->req_opts_size,
 259                                        client->req_opts);
 260                 if (r < 0)
 261                         return r;
 262
 263                 /* Some DHCP servers will send bigger DHCP packets than the
 264                    defined default size unless the Maximum Messge Size option
 265                    is explicitely set */
 266                 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
 267                                    DHCP_MIN_OPTIONS_SIZE);
 268                 r = dhcp_option_append(opt, optlen,
 269                                        DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
 270                                        2, &max_size);
 271                 if (r < 0)
 272                         return r;
 273         }
 274
 275         return 0;
 276 }
 277
 278 static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
 279                                 size_t len) {
 280         dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
 281                                       INADDR_BROADCAST, DHCP_PORT_SERVER, len);
 282
 283         return dhcp_network_send_raw_socket(client->fd, &client->link,
 284                                             packet, len);
 285 }
 286
 287 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
 288         int err = 0;
 289         _cleanup_free_ DHCPPacket *discover;
 290         size_t optlen, len;
 291         uint8_t *opt;
 292
 293         optlen = DHCP_MIN_OPTIONS_SIZE;
 294         len = sizeof(DHCPPacket) + optlen;
 295
 296         discover = malloc0(len);
 297
 298         if (!discover)
 299                 return -ENOMEM;
 300
 301         err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
 302                                   secs, &opt, &optlen);
 303         if (err < 0)
 304                 return err;
 305
 306         if (client->last_addr != INADDR_ANY) {
 307                 err = dhcp_option_append(&opt, &optlen,
 308                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 309                                          4, &client->last_addr);
 310                 if (err < 0)
 311                         return err;
 312         }
 313
 314         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 315         if (err < 0)
 316                 return err;
 317
 318         err = dhcp_client_send_raw(client, discover, len - optlen);
 319         if (err < 0)
 320                 return err;
 321
 322         log_dhcp_client(client, "DISCOVER");
 323
 324         return 0;
 325 }
 326
 327 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
 328         _cleanup_free_ DHCPPacket *request;
 329         size_t optlen, len;
 330         int err;
 331         uint8_t *opt;
 332
 333         optlen = DHCP_MIN_OPTIONS_SIZE;
 334         len = sizeof(DHCPPacket) + optlen;
 335
 336         request = malloc0(len);
 337         if (!request)
 338                 return -ENOMEM;
 339
 340         err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
 341                                   &opt, &optlen);
 342         if (err < 0)
 343                 return err;
 344
 345         switch (client->state) {
 346
 347         case DHCP_STATE_INIT_REBOOT:
 348                 err = dhcp_option_append(&opt, &optlen,
 349                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 350                                          4, &client->last_addr);
 351                 if (err < 0)
 352                         return err;
 353                 break;
 354
 355         case DHCP_STATE_REQUESTING:
 356                 err = dhcp_option_append(&opt, &optlen,
 357                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 358                                          4, &client->lease->address);
 359                 if (err < 0)
 360                         return err;
 361
 362                 err = dhcp_option_append(&opt, &optlen,
 363                                          DHCP_OPTION_SERVER_IDENTIFIER,
 364                                          4, &client->lease->server_address);
 365                 if (err < 0)
 366                         return err;
 367                 break;
 368
 369         case DHCP_STATE_INIT:
 370         case DHCP_STATE_SELECTING:
 371         case DHCP_STATE_REBOOTING:
 372         case DHCP_STATE_BOUND:
 373         case DHCP_STATE_RENEWING:
 374         case DHCP_STATE_REBINDING:
 375
 376                 break;
 377         }
 378
 379         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 380         if (err < 0)
 381                 return err;
 382
 383         if (client->state == DHCP_STATE_RENEWING) {
 384                 err = dhcp_network_send_udp_socket(client->fd,
 385                                                    client->lease->server_address,
 386                                                    DHCP_PORT_SERVER,
 387                                                    &request->dhcp,
 388                                                    len - optlen - DHCP_IP_UDP_SIZE);
 389         } else {
 390                 err = dhcp_client_send_raw(client, request, len - optlen);
 391         }
 392         if (err < 0)
 393                 return err;
 394
 395         log_dhcp_client(client, "REQUEST");
 396
 397         return 0;
 398 }
 399
 400 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
 401 {
 402         client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
 403
 404         return client->secs;
 405 }
 406
 407 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 408                                  void *userdata) {
 409         sd_dhcp_client *client = userdata;
 410         usec_t next_timeout = 0;
 411         uint64_t time_now;
 412         uint32_t time_left;
 413         int r;
 414
 415         assert(s);
 416         assert(client);
 417         assert(client->event);
 418
 419         r = sd_event_get_now_monotonic(client->event, &time_now);
 420         if (r < 0)
 421                 goto error;
 422
 423         switch (client->state) {
 424         case DHCP_STATE_RENEWING:
 425
 426                 time_left = (client->lease->t2 - client->lease->t1) / 2;
 427                 if (time_left < 60)
 428                         time_left = 60;
 429
 430                 next_timeout = time_now + time_left * USEC_PER_SEC;
 431
 432                 break;
 433
 434         case DHCP_STATE_REBINDING:
 435
 436                 time_left = (client->lease->lifetime - client->lease->t2) / 2;
 437                 if (time_left < 60)
 438                         time_left = 60;
 439
 440                 next_timeout = time_now + time_left * USEC_PER_SEC;
 441                 break;
 442
 443         case DHCP_STATE_REBOOTING:
 444                 /* start over as we did not receive a timely ack or nak */
 445                 client->state = DHCP_STATE_INIT;
 446                 client->attempt = 1;
 447                 client->xid = random_u32();
 448
 449                 /* fall through */
 450         case DHCP_STATE_INIT:
 451         case DHCP_STATE_INIT_REBOOT:
 452         case DHCP_STATE_SELECTING:
 453         case DHCP_STATE_REQUESTING:
 454         case DHCP_STATE_BOUND:
 455
 456                 if (client->attempt < 64)
 457                         client->attempt *= 2;
 458
 459                 next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC;
 460
 461                 break;
 462         }
 463
 464         next_timeout += (random_u32() & 0x1fffff);
 465
 466         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 467
 468         r = sd_event_add_monotonic(client->event,
 469                                      &client->timeout_resend,
 470                                      next_timeout,
 471                                      10 * USEC_PER_MSEC,
 472                                      client_timeout_resend, client);
 473         if (r < 0)
 474                 goto error;
 475
 476         r = sd_event_source_set_priority(client->timeout_resend,
 477                                          client->event_priority);
 478         if (r < 0)
 479                 goto error;
 480
 481         switch (client->state) {
 482         case DHCP_STATE_INIT:
 483
 484                 client_update_secs(client, time_now);
 485
 486                 r = client_send_discover(client, client->secs);
 487                 if (r >= 0) {
 488                         client->state = DHCP_STATE_SELECTING;
 489                         client->attempt = 1;
 490                 } else {
 491                         if (client->attempt >= 64)
 492                                 goto error;
 493                 }
 494
 495                 break;
 496
 497         case DHCP_STATE_SELECTING:
 498                 client_update_secs(client, time_now);
 499
 500                 r = client_send_discover(client, client->secs);
 501                 if (r < 0 && client->attempt >= 64)
 502                         goto error;
 503
 504                 break;
 505
 506         case DHCP_STATE_INIT_REBOOT:
 507         case DHCP_STATE_REQUESTING:
 508         case DHCP_STATE_RENEWING:
 509         case DHCP_STATE_REBINDING:
 510                 r = client_send_request(client, client->secs);
 511                 if (r < 0 && client->attempt >= 64)
 512                          goto error;
 513
 514                 if (client->state == DHCP_STATE_INIT_REBOOT)
 515                         client->state = DHCP_STATE_REBOOTING;
 516
 517                 client->request_sent = time_now;
 518
 519                 break;
 520
 521         case DHCP_STATE_REBOOTING:
 522         case DHCP_STATE_BOUND:
 523
 524                 break;
 525         }
 526
 527         return 0;
 528
 529 error:
 530         client_stop(client, r);
 531
 532         /* Errors were dealt with when stopping the client, don't spill
 533            errors into the event loop handler */
 534         return 0;
 535 }
 536
 537 static int client_initialize_events(sd_dhcp_client *client,
 538                                     sd_event_io_handler_t io_callback) {
 539         int r;
 540
 541         assert(client);
 542         assert(client->event);
 543
 544         r = sd_event_add_io(client->event, &client->receive_message,
 545                             client->fd, EPOLLIN, io_callback,
 546                             client);
 547         if (r < 0)
 548                 goto error;
 549
 550         r = sd_event_source_set_priority(client->receive_message,
 551                                          client->event_priority);
 552         if (r < 0)
 553                 goto error;
 554
 555         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 556
 557         r = sd_event_add_monotonic(client->event,
 558                                    &client->timeout_resend, 0, 0,
 559                                    client_timeout_resend, client);
 560         if (r < 0)
 561                 goto error;
 562
 563         r = sd_event_source_set_priority(client->timeout_resend,
 564                                          client->event_priority);
 565
 566 error:
 567         if (r < 0)
 568                 client_stop(client, r);
 569
 570         return 0;
 571
 572 }
 573
 574 static int client_start(sd_dhcp_client *client) {
 575         int r;
 576
 577         assert_return(client, -EINVAL);
 578         assert_return(client->event, -EINVAL);
 579         assert_return(client->index > 0, -EINVAL);
 580         assert_return(client->fd < 0, -EBUSY);
 581         assert_return(client->xid == 0, -EINVAL);
 582         assert_return(client->state == DHCP_STATE_INIT ||
 583                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 584
 585         client->xid = random_u32();
 586
 587         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 588
 589         if (r < 0) {
 590                 client_stop(client, r);
 591                 return r;
 592         }
 593
 594         client->fd = r;
 595         client->start_time = now(CLOCK_MONOTONIC);
 596         client->secs = 0;
 597
 598         log_dhcp_client(client, "STARTED");
 599
 600         return client_initialize_events(client, client_receive_message_raw);
 601 }
 602
 603 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 604                                  void *userdata) {
 605         sd_dhcp_client *client = userdata;
 606
 607         log_dhcp_client(client, "EXPIRED");
 608
 609         client_notify(client, DHCP_EVENT_EXPIRED);
 610
 611         /* start over as the lease was lost */
 612         client_initialize(client);
 613         client_start(client);
 614
 615         return 0;
 616 }
 617
 618 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
 619         sd_dhcp_client *client = userdata;
 620         int r;
 621
 622         client->receive_message = sd_event_source_unref(client->receive_message);
 623         client->fd = safe_close(client->fd);
 624
 625         client->state = DHCP_STATE_REBINDING;
 626         client->attempt = 1;
 627
 628         r = dhcp_network_bind_raw_socket(client->index, &client->link);
 629         if (r < 0) {
 630                 client_stop(client, r);
 631                 return 0;
 632         }
 633
 634         client->fd = r;
 635
 636         log_dhcp_client(client, "TIMEOUT T2");
 637
 638         return client_initialize_events(client, client_receive_message_raw);
 639 }
 640
 641 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
 642                              void *userdata) {
 643         sd_dhcp_client *client = userdata;
 644         int r;
 645
 646         client->state = DHCP_STATE_RENEWING;
 647         client->attempt = 1;
 648
 649         r = dhcp_network_bind_udp_socket(client->index,
 650                                          client->lease->address,
 651                                          DHCP_PORT_CLIENT);
 652         if (r < 0) {
 653                 client_stop(client, r);
 654                 return 0;
 655         }
 656
 657         client->fd = r;
 658
 659         log_dhcp_client(client, "TIMEOUT T1");
 660
 661         return client_initialize_events(client, client_receive_message_udp);
 662 }
 663
 664 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
 665                                size_t len) {
 666         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 667         int r;
 668
 669         r = dhcp_lease_new(&lease);
 670         if (r < 0)
 671                 return r;
 672
 673         r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
 674         if (r != DHCP_OFFER)
 675                 return -ENOMSG;
 676
 677         lease->next_server = offer->siaddr;
 678
 679         lease->address = offer->yiaddr;
 680
 681         if (lease->address == INADDR_ANY ||
 682             lease->server_address == INADDR_ANY ||
 683             lease->subnet_mask == INADDR_ANY ||
 684             lease->lifetime == 0)
 685                 return -ENOMSG;
 686
 687         client->lease = lease;
 688         lease = NULL;
 689
 690         log_dhcp_client(client, "OFFER");
 691
 692         return 0;
 693 }
 694
 695 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
 696                              size_t len) {
 697         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 698         int r;
 699
 700         r = dhcp_lease_new(&lease);
 701         if (r < 0)
 702                 return r;
 703
 704         r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
 705         if (r == DHCP_NAK) {
 706                 log_dhcp_client(client, "NAK");
 707                 return DHCP_EVENT_NO_LEASE;
 708         }
 709
 710         if (r != DHCP_ACK)
 711                 return -ENOMSG;
 712
 713         lease->next_server = ack->siaddr;
 714
 715         lease->address = ack->yiaddr;
 716
 717         if (lease->address == INADDR_ANY ||
 718             lease->server_address == INADDR_ANY ||
 719             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
 720                 return -ENOMSG;
 721
 722         r = DHCP_EVENT_IP_ACQUIRE;
 723         if (client->lease) {
 724                 if (client->lease->address != lease->address ||
 725                     client->lease->subnet_mask != lease->subnet_mask ||
 726                     client->lease->router != lease->router) {
 727                         r = DHCP_EVENT_IP_CHANGE;
 728                 }
 729
 730                 client->lease = sd_dhcp_lease_unref(client->lease);
 731         }
 732
 733         client->lease = lease;
 734         lease = NULL;
 735
 736         log_dhcp_client(client, "ACK");
 737
 738         return r;
 739 }
 740
 741 static uint64_t client_compute_timeout(uint64_t request_sent,
 742                                        uint32_t lifetime) {
 743         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 744                 + (random_u32() & 0x1fffff);
 745 }
 746
 747 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
 748         uint64_t next_timeout;
 749         int r;
 750
 751         assert(client);
 752         assert(client->event);
 753
 754         /* don't set timers for infinite leases */
 755         if (client->lease->lifetime == 0xffffffff)
 756                 return 0;
 757
 758         if (client->lease->lifetime < 10)
 759                 return -EINVAL;
 760
 761         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 762         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 763         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 764
 765         if (!client->lease->t1)
 766                 client->lease->t1 = client->lease->lifetime / 2;
 767
 768         next_timeout = client_compute_timeout(client->request_sent,
 769                                               client->lease->t1);
 770         if (next_timeout < usec)
 771                 return -EINVAL;
 772
 773         r = sd_event_add_monotonic(client->event,
 774                                    &client->timeout_t1,
 775                                    next_timeout,
 776                                    10 * USEC_PER_MSEC,
 777                                    client_timeout_t1, client);
 778         if (r < 0)
 779                 return r;
 780
 781         r = sd_event_source_set_priority(client->timeout_t1,
 782                                          client->event_priority);
 783         if (r < 0)
 784                 return r;
 785
 786         if (!client->lease->t2)
 787                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 788
 789         if (client->lease->t2 < client->lease->t1)
 790                 return -EINVAL;
 791
 792         if (client->lease->lifetime < client->lease->t2)
 793                 return -EINVAL;
 794
 795         next_timeout = client_compute_timeout(client->request_sent,
 796                                               client->lease->t2);
 797         if (next_timeout < usec)
 798                 return -EINVAL;
 799
 800         r = sd_event_add_monotonic(client->event,
 801                                    &client->timeout_t2,
 802                                    next_timeout,
 803                                    10 * USEC_PER_MSEC,
 804                                    client_timeout_t2, client);
 805         if (r < 0)
 806                 return r;
 807
 808         r = sd_event_source_set_priority(client->timeout_t2,
 809                                          client->event_priority);
 810         if (r < 0)
 811                 return r;
 812
 813         next_timeout = client_compute_timeout(client->request_sent,
 814                                               client->lease->lifetime);
 815         if (next_timeout < usec)
 816                 return -EINVAL;
 817
 818         r = sd_event_add_monotonic(client->event,
 819                                    &client->timeout_expire, next_timeout,
 820                                    10 * USEC_PER_MSEC,
 821                                    client_timeout_expire, client);
 822         if (r < 0)
 823                 return r;
 824
 825         r = sd_event_source_set_priority(client->timeout_expire,
 826                                          client->event_priority);
 827         if (r < 0)
 828                 return r;
 829
 830         return 0;
 831 }
 832
 833 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
 834                                  int len, usec_t time_now) {
 835         int r = 0, notify_event = 0;
 836
 837         assert(client);
 838         assert(client->event);
 839         assert(message);
 840
 841         if (len < DHCP_MESSAGE_SIZE) {
 842                 log_dhcp_client(client, "message too small (%d bytes): "
 843                                 "ignoring", len);
 844                 return 0;
 845         }
 846
 847         if (message->op != BOOTREPLY) {
 848                 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
 849                 return 0;
 850         }
 851
 852         if (be32toh(message->xid) != client->xid) {
 853                 log_dhcp_client(client, "received xid (%u) does not match "
 854                                 "expected (%u): ignoring",
 855                                 be32toh(message->xid), client->xid);
 856                 return 0;
 857         }
 858
 859         if (memcmp(&message->chaddr[0], &client->client_id.mac_addr,
 860                    ETH_ALEN)) {
 861                 log_dhcp_client(client, "received chaddr does not match "
 862                                 "expected: ignoring");
 863                 return 0;
 864         }
 865
 866         switch (client->state) {
 867         case DHCP_STATE_SELECTING:
 868
 869                 r = client_handle_offer(client, message, len);
 870                 if (r >= 0) {
 871
 872                         client->timeout_resend =
 873                                 sd_event_source_unref(client->timeout_resend);
 874
 875                         client->state = DHCP_STATE_REQUESTING;
 876                         client->attempt = 1;
 877
 878                         r = sd_event_add_monotonic(client->event,
 879                                                    &client->timeout_resend, 0,
 880                                                    0, client_timeout_resend,
 881                                                    client);
 882                         if (r < 0)
 883                                 goto error;
 884
 885                         r = sd_event_source_set_priority(client->timeout_resend,
 886                                                          client->event_priority);
 887                         if (r < 0)
 888                                 goto error;
 889                 }
 890
 891                 break;
 892
 893         case DHCP_STATE_REBOOTING:
 894         case DHCP_STATE_REQUESTING:
 895         case DHCP_STATE_RENEWING:
 896         case DHCP_STATE_REBINDING:
 897
 898                 r = client_handle_ack(client, message, len);
 899
 900                 if (r == DHCP_EVENT_NO_LEASE) {
 901
 902                         client->timeout_resend =
 903                                 sd_event_source_unref(client->timeout_resend);
 904
 905                         if (client->state == DHCP_STATE_REBOOTING) {
 906                                 r = client_initialize(client);
 907                                 if (r < 0)
 908                                         goto error;
 909
 910                                 r = client_start(client);
 911                                 if (r < 0)
 912                                         goto error;
 913                         }
 914
 915                         goto error;
 916                 }
 917
 918                 if (r >= 0) {
 919                         client->timeout_resend =
 920                                 sd_event_source_unref(client->timeout_resend);
 921
 922                         if (IN_SET(client->state, DHCP_STATE_REQUESTING,
 923                                    DHCP_STATE_REBOOTING))
 924                                 notify_event = DHCP_EVENT_IP_ACQUIRE;
 925                         else if (r != DHCP_EVENT_IP_ACQUIRE)
 926                                 notify_event = r;
 927
 928                         client->state = DHCP_STATE_BOUND;
 929                         client->attempt = 1;
 930
 931                         client->last_addr = client->lease->address;
 932
 933                         r = client_set_lease_timeouts(client, time_now);
 934                         if (r < 0)
 935                                 goto error;
 936
 937                         if (notify_event)
 938                                 client_notify(client, notify_event);
 939
 940                         client->receive_message =
 941                                 sd_event_source_unref(client->receive_message);
 942                         client->fd = safe_close(client->fd);
 943                 }
 944
 945                 r = 0;
 946
 947                 break;
 948
 949         case DHCP_STATE_INIT:
 950         case DHCP_STATE_INIT_REBOOT:
 951         case DHCP_STATE_BOUND:
 952
 953                 break;
 954         }
 955
 956 error:
 957         if (r < 0 || r == DHCP_EVENT_NO_LEASE)
 958                 return client_stop(client, r);
 959
 960         return 0;
 961 }
 962
 963 static int client_receive_message_udp(sd_event_source *s, int fd,
 964                                       uint32_t revents, void *userdata) {
 965         sd_dhcp_client *client = userdata;
 966         _cleanup_free_ DHCPMessage *message = NULL;
 967         int buflen = 0, len, r;
 968         usec_t time_now;
 969
 970         assert(s);
 971         assert(client);
 972         assert(client->event);
 973
 974         r = ioctl(fd, FIONREAD, &buflen);
 975         if (r < 0 || buflen <= 0)
 976                 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
 977
 978         message = malloc0(buflen);
 979         if (!message)
 980                 return -ENOMEM;
 981
 982         len = read(fd, message, buflen);
 983         if (len < 0)
 984                 return 0;
 985
 986         r = sd_event_get_now_monotonic(client->event, &time_now);
 987         if (r < 0)
 988                 return client_stop(client, r);
 989
 990         return client_handle_message(client, message, len,
 991                                      time_now);
 992 }
 993
 994 static int client_receive_message_raw(sd_event_source *s, int fd,
 995                                       uint32_t revents, void *userdata) {
 996         sd_dhcp_client *client = userdata;
 997         _cleanup_free_ DHCPPacket *packet = NULL;
 998         usec_t time_now;
 999         uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
1000         struct iovec iov = {};
1001         struct msghdr msg = {
1002                 .msg_iov = &iov,
1003                 .msg_iovlen = 1,
1004                 .msg_control = cmsgbuf,
1005                 .msg_controllen = sizeof(cmsgbuf),
1006         };
1007         struct cmsghdr *cmsg;
1008         bool checksum = true;
1009         int buflen = 0, len, r;
1010
1011         assert(s);
1012         assert(client);
1013         assert(client->event);
1014
1015         r = ioctl(fd, FIONREAD, &buflen);
1016         if (r < 0 || buflen <= 0)
1017                 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
1018
1019         packet = malloc0(buflen);
1020         if (!packet)
1021                 return -ENOMEM;
1022
1023         iov.iov_base = packet;
1024         iov.iov_len = buflen;
1025
1026         len = recvmsg(fd, &msg, 0);
1027         if (len < 0) {
1028                 log_dhcp_client(client, "could not receive message from raw "
1029                                 "socket: %s", strerror(errno));
1030                 return 0;
1031         }
1032
1033         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
1034                 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
1035                         struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
1036
1037                         checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
1038                         break;
1039                 }
1040         }
1041
1042         r = dhcp_packet_verify_headers(packet, len, checksum);
1043         if (r < 0)
1044                 return 0;
1045
1046         len -= DHCP_IP_UDP_SIZE;
1047
1048         r = sd_event_get_now_monotonic(client->event, &time_now);
1049         if (r < 0)
1050                 return client_stop(client, r);
1051
1052         return client_handle_message(client, &packet->dhcp, len, time_now);
1053 }
1054
1055 int sd_dhcp_client_start(sd_dhcp_client *client) {
1056         int r;
1057
1058         assert_return(client, -EINVAL);
1059
1060         r = client_initialize(client);
1061         if (r < 0)
1062                 return r;
1063
1064         if (client->last_addr)
1065                 client->state = DHCP_STATE_INIT_REBOOT;
1066
1067         return client_start(client);
1068 }
1069
1070 int sd_dhcp_client_stop(sd_dhcp_client *client) {
1071         return client_stop(client, DHCP_EVENT_STOP);
1072 }
1073
1074 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
1075                                 int priority) {
1076         int r;
1077
1078         assert_return(client, -EINVAL);
1079         assert_return(!client->event, -EBUSY);
1080
1081         if (event)
1082                 client->event = sd_event_ref(event);
1083         else {
1084                 r = sd_event_default(&client->event);
1085                 if (r < 0)
1086                         return 0;
1087         }
1088
1089         client->event_priority = priority;
1090
1091         return 0;
1092 }
1093
1094 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
1095         assert_return(client, -EINVAL);
1096
1097         client->event = sd_event_unref(client->event);
1098
1099         return 0;
1100 }
1101
1102 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
1103         if (!client)
1104                 return NULL;
1105
1106         return client->event;
1107 }
1108
1109 void sd_dhcp_client_free(sd_dhcp_client *client) {
1110         if (!client)
1111                 return;
1112
1113         sd_dhcp_client_stop(client);
1114         sd_dhcp_client_detach_event(client);
1115
1116         free(client->req_opts);
1117         free(client);
1118 }
1119
1120 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
1121 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
1122
1123 int sd_dhcp_client_new(sd_dhcp_client **ret) {
1124         _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
1125
1126         assert_return(ret, -EINVAL);
1127
1128         client = new0(sd_dhcp_client, 1);
1129         if (!client)
1130                 return -ENOMEM;
1131
1132         client->state = DHCP_STATE_INIT;
1133         client->index = -1;
1134         client->fd = -1;
1135         client->attempt = 1;
1136
1137         client->req_opts_size = ELEMENTSOF(default_req_opts);
1138
1139         client->req_opts = memdup(default_req_opts, client->req_opts_size);
1140         if (!client->req_opts)
1141                 return -ENOMEM;
1142
1143         *ret = client;
1144         client = NULL;
1145
1146         return 0;
1147 }