src/libsystemd-dhcp/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
  26 #include "util.h"
  27 #include "list.h"
  28
  29 #include "dhcp-protocol.h"
  30 #include "dhcp-internal.h"
  31 #include "sd-dhcp-client.h"
  32
  33 #define DHCP_CLIENT_MIN_OPTIONS_SIZE            312
  34
  35 struct DHCPLease {
  36         uint32_t t1;
  37         uint32_t t2;
  38         uint32_t lifetime;
  39         uint32_t address;
  40         uint32_t server_address;
  41         uint32_t subnet_mask;
  42         uint32_t router;
  43 };
  44
  45 typedef struct DHCPLease DHCPLease;
  46
  47 struct sd_dhcp_client {
  48         DHCPState state;
  49         sd_event *event;
  50         sd_event_source *timeout_resend;
  51         int index;
  52         int fd;
  53         union sockaddr_union link;
  54         sd_event_source *receive_message;
  55         uint8_t *req_opts;
  56         size_t req_opts_size;
  57         uint32_t last_addr;
  58         struct ether_addr mac_addr;
  59         uint32_t xid;
  60         usec_t start_time;
  61         unsigned int attempt;
  62         usec_t request_sent;
  63         sd_event_source *timeout_t1;
  64         sd_event_source *timeout_t2;
  65         sd_event_source *timeout_expire;
  66         DHCPLease *lease;
  67 };
  68
  69 static const uint8_t default_req_opts[] = {
  70         DHCP_OPTION_SUBNET_MASK,
  71         DHCP_OPTION_ROUTER,
  72         DHCP_OPTION_HOST_NAME,
  73         DHCP_OPTION_DOMAIN_NAME,
  74         DHCP_OPTION_DOMAIN_NAME_SERVER,
  75         DHCP_OPTION_NTP_SERVER,
  76 };
  77
  78 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
  79 {
  80         size_t i;
  81
  82         assert_return(client, -EINVAL);
  83         assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
  84
  85         switch(option) {
  86         case DHCP_OPTION_PAD:
  87         case DHCP_OPTION_OVERLOAD:
  88         case DHCP_OPTION_MESSAGE_TYPE:
  89         case DHCP_OPTION_PARAMETER_REQUEST_LIST:
  90         case DHCP_OPTION_END:
  91                 return -EINVAL;
  92
  93         default:
  94                 break;
  95         }
  96
  97         for (i = 0; i < client->req_opts_size; i++)
  98                 if (client->req_opts[i] == option)
  99                         return -EEXIST;
 100
 101         if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
 102                             client->req_opts_size + 1))
 103                 return -ENOMEM;
 104
 105         client->req_opts[client->req_opts_size - 1] = option;
 106
 107         return 0;
 108 }
 109
 110 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
 111                                        const struct in_addr *last_addr)
 112 {
 113         assert_return(client, -EINVAL);
 114         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 115
 116         if (last_addr)
 117                 client->last_addr = last_addr->s_addr;
 118         else
 119                 client->last_addr = INADDR_ANY;
 120
 121         return 0;
 122 }
 123
 124 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
 125 {
 126         assert_return(client, -EINVAL);
 127         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 128         assert_return(interface_index >= -1, -EINVAL);
 129
 130         client->index = interface_index;
 131
 132         return 0;
 133 }
 134
 135 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
 136                            const struct ether_addr *addr)
 137 {
 138         assert_return(client, -EINVAL);
 139         assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
 140
 141         memcpy(&client->mac_addr, addr, ETH_ALEN);
 142
 143         return 0;
 144 }
 145
 146 static int client_notify(sd_dhcp_client *client, int event)
 147 {
 148         return 0;
 149 }
 150
 151 static int client_stop(sd_dhcp_client *client, int error)
 152 {
 153         assert_return(client, -EINVAL);
 154         assert_return(client->state != DHCP_STATE_INIT &&
 155                       client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
 156
 157         client->receive_message =
 158                 sd_event_source_unref(client->receive_message);
 159
 160         if (client->fd >= 0)
 161                 close(client->fd);
 162         client->fd = -1;
 163
 164         client->timeout_resend = sd_event_source_unref(client->timeout_resend);
 165
 166         client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
 167         client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
 168         client->timeout_expire = sd_event_source_unref(client->timeout_expire);
 169
 170         client->attempt = 1;
 171
 172         switch (client->state) {
 173
 174         case DHCP_STATE_INIT:
 175         case DHCP_STATE_SELECTING:
 176         case DHCP_STATE_REQUESTING:
 177         case DHCP_STATE_BOUND:
 178
 179                 client->start_time = 0;
 180                 client->state = DHCP_STATE_INIT;
 181                 break;
 182
 183         case DHCP_STATE_INIT_REBOOT:
 184         case DHCP_STATE_REBOOTING:
 185         case DHCP_STATE_RENEWING:
 186         case DHCP_STATE_REBINDING:
 187
 188                 break;
 189         }
 190
 191         if (client->lease) {
 192                 free(client->lease);
 193                 client->lease = NULL;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
 200                               DHCPMessage *message, uint16_t secs,
 201                               uint8_t **opt, size_t *optlen)
 202 {
 203         int err;
 204         be16_t max_size;
 205
 206         *opt = (uint8_t *)(message + 1);
 207
 208         if (*optlen < 4)
 209                 return -ENOBUFS;
 210         *optlen -= 4;
 211
 212         message->op = BOOTREQUEST;
 213         message->htype = 1;
 214         message->hlen = ETHER_ADDR_LEN;
 215         message->xid = htobe32(client->xid);
 216
 217         /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
 218            refuse to issue an DHCP lease if 'secs' is set to zero */
 219         message->secs = htobe16(secs);
 220
 221         memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
 222         (*opt)[0] = 0x63;
 223         (*opt)[1] = 0x82;
 224         (*opt)[2] = 0x53;
 225         (*opt)[3] = 0x63;
 226
 227         *opt += 4;
 228
 229         err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
 230                                  &type);
 231         if (err < 0)
 232                 return err;
 233
 234         /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
 235            Identifier option is not set */
 236         err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
 237                                  ETH_ALEN, &client->mac_addr);
 238         if (err < 0)
 239                 return err;
 240
 241         if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
 242                 err = dhcp_option_append(opt, optlen,
 243                                          DHCP_OPTION_PARAMETER_REQUEST_LIST,
 244                                          client->req_opts_size,
 245                                          client->req_opts);
 246                 if (err < 0)
 247                         return err;
 248
 249                 /* Some DHCP servers will send bigger DHCP packets than the
 250                    defined default size unless the Maximum Messge Size option
 251                    is explicitely set */
 252                 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
 253                                    DHCP_CLIENT_MIN_OPTIONS_SIZE);
 254                 err = dhcp_option_append(opt, optlen,
 255                                          DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
 256                                          2, &max_size);
 257                 if (err < 0)
 258                         return err;
 259         }
 260
 261         return 0;
 262 }
 263
 264 static uint16_t client_checksum(void *buf, int len)
 265 {
 266         uint32_t sum;
 267         uint16_t *check;
 268         int i;
 269         uint8_t *odd;
 270
 271         sum = 0;
 272         check = buf;
 273
 274         for (i = 0; i < len / 2 ; i++)
 275                 sum += check[i];
 276
 277         if (len & 0x01) {
 278                 odd = buf;
 279                 sum += odd[len];
 280         }
 281
 282         return ~((sum & 0xffff) + (sum >> 16));
 283 }
 284
 285 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
 286 {
 287         packet->ip.version = IPVERSION;
 288         packet->ip.ihl = DHCP_IP_SIZE / 4;
 289         packet->ip.tot_len = htobe16(len);
 290
 291         packet->ip.protocol = IPPROTO_UDP;
 292         packet->ip.saddr = INADDR_ANY;
 293         packet->ip.daddr = INADDR_BROADCAST;
 294
 295         packet->udp.source = htobe16(DHCP_PORT_CLIENT);
 296         packet->udp.dest = htobe16(DHCP_PORT_SERVER);
 297         packet->udp.len = htobe16(len - DHCP_IP_SIZE);
 298
 299         packet->ip.check = packet->udp.len;
 300         packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
 301
 302         packet->ip.ttl = IPDEFTTL;
 303         packet->ip.check = 0;
 304         packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
 305 }
 306
 307 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
 308 {
 309         int err = 0;
 310         _cleanup_free_ DHCPPacket *discover;
 311         size_t optlen, len;
 312         uint8_t *opt;
 313
 314         optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
 315         len = sizeof(DHCPPacket) + optlen;
 316
 317         discover = malloc0(len);
 318
 319         if (!discover)
 320                 return -ENOMEM;
 321
 322         err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
 323                                  secs, &opt, &optlen);
 324         if (err < 0)
 325                 return err;
 326
 327         if (client->last_addr != INADDR_ANY) {
 328                 err = dhcp_option_append(&opt, &optlen,
 329                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 330                                          4, &client->last_addr);
 331                 if (err < 0)
 332                         return err;
 333         }
 334
 335         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 336         if (err < 0)
 337                 return err;
 338
 339         client_append_ip_headers(discover, len);
 340
 341         err = dhcp_network_send_raw_socket(client->fd, &client->link,
 342                                            discover, len);
 343
 344         return err;
 345 }
 346
 347 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
 348 {
 349         _cleanup_free_ DHCPPacket *request;
 350         size_t optlen, len;
 351         int err;
 352         uint8_t *opt;
 353
 354         optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
 355         len = DHCP_MESSAGE_SIZE + optlen;
 356
 357         request = malloc0(len);
 358         if (!request)
 359                 return -ENOMEM;
 360
 361         err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
 362                                  &opt, &optlen);
 363         if (err < 0)
 364                 return err;
 365
 366         if (client->state == DHCP_STATE_REQUESTING) {
 367                 err = dhcp_option_append(&opt, &optlen,
 368                                          DHCP_OPTION_REQUESTED_IP_ADDRESS,
 369                                          4, &client->lease->address);
 370                 if (err < 0)
 371                         return err;
 372
 373                 err = dhcp_option_append(&opt, &optlen,
 374                                          DHCP_OPTION_SERVER_IDENTIFIER,
 375                                          4, &client->lease->server_address);
 376                 if (err < 0)
 377                         return err;
 378         }
 379
 380         err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
 381         if (err < 0)
 382                 return err;
 383
 384         client_append_ip_headers(request, len);
 385
 386         err = dhcp_network_send_raw_socket(client->fd, &client->link,
 387                                            request, len);
 388
 389         return err;
 390 }
 391
 392 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
 393                                  void *userdata)
 394 {
 395         sd_dhcp_client *client = userdata;
 396         usec_t next_timeout;
 397         uint16_t secs;
 398         int err = 0;
 399
 400         secs = (usec - client->start_time) / USEC_PER_SEC;
 401
 402         if (client->attempt < 64)
 403                 client->attempt *= 2;
 404
 405         next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
 406                 (random_u() & 0x1fffff);
 407
 408         err = sd_event_add_monotonic(client->event, next_timeout,
 409                                      10 * USEC_PER_MSEC,
 410                                      client_timeout_resend, client,
 411                                      &client->timeout_resend);
 412         if (err < 0)
 413                 goto error;
 414
 415         switch (client->state) {
 416         case DHCP_STATE_INIT:
 417                 err = client_send_discover(client, secs);
 418                 if (err >= 0) {
 419                         client->state = DHCP_STATE_SELECTING;
 420                         client->attempt = 1;
 421                 } else {
 422                         if (client->attempt >= 64)
 423                                 goto error;
 424                 }
 425
 426                 break;
 427
 428         case DHCP_STATE_SELECTING:
 429                 err = client_send_discover(client, secs);
 430                 if (err < 0 && client->attempt >= 64)
 431                         goto error;
 432
 433                 break;
 434
 435         case DHCP_STATE_REQUESTING:
 436                 err = client_send_request(client, secs);
 437                 if (err < 0 && client->attempt >= 64)
 438                          goto error;
 439
 440                 client->request_sent = usec;
 441
 442                 break;
 443
 444         case DHCP_STATE_INIT_REBOOT:
 445         case DHCP_STATE_REBOOTING:
 446         case DHCP_STATE_BOUND:
 447         case DHCP_STATE_RENEWING:
 448         case DHCP_STATE_REBINDING:
 449
 450                 break;
 451         }
 452
 453         return 0;
 454
 455 error:
 456         client_stop(client, err);
 457
 458         /* Errors were dealt with when stopping the client, don't spill
 459            errors into the event loop handler */
 460         return 0;
 461 }
 462
 463 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
 464                                  void *userdata)
 465 {
 466         return 0;
 467 }
 468
 469 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
 470 {
 471         return 0;
 472 }
 473
 474 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
 475 {
 476         return 0;
 477 }
 478
 479 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
 480                               void *user_data)
 481 {
 482         DHCPLease *lease = user_data;
 483         be32_t val;
 484
 485         switch(code) {
 486
 487         case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
 488                 if (len == 4) {
 489                         memcpy(&val, option, 4);
 490                         lease->lifetime = be32toh(val);
 491                 }
 492
 493                 break;
 494
 495         case DHCP_OPTION_SERVER_IDENTIFIER:
 496                 if (len >= 4)
 497                         memcpy(&lease->server_address, option, 4);
 498
 499                 break;
 500
 501         case DHCP_OPTION_SUBNET_MASK:
 502                 if (len >= 4)
 503                         memcpy(&lease->subnet_mask, option, 4);
 504
 505                 break;
 506
 507         case DHCP_OPTION_ROUTER:
 508                 if (len >= 4)
 509                         memcpy(&lease->router, option, 4);
 510
 511                 break;
 512
 513         case DHCP_OPTION_RENEWAL_T1_TIME:
 514                 if (len == 4) {
 515                         memcpy(&val, option, 4);
 516                         lease->t1 = be32toh(val);
 517                 }
 518
 519                 break;
 520
 521         case DHCP_OPTION_REBINDING_T2_TIME:
 522                 if (len == 4) {
 523                         memcpy(&val, option, 4);
 524                         lease->t2 = be32toh(val);
 525                 }
 526
 527                 break;
 528         }
 529
 530         return 0;
 531 }
 532
 533 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
 534                                  size_t len)
 535 {
 536         size_t hdrlen;
 537
 538         if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
 539                 return -EINVAL;
 540
 541         hdrlen = message->ip.ihl * 4;
 542         if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
 543                                                            hdrlen))
 544                 return -EINVAL;
 545
 546         message->ip.check = message->udp.len;
 547         message->ip.ttl = 0;
 548
 549         if (hdrlen + be16toh(message->udp.len) > len ||
 550             client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
 551                 return -EINVAL;
 552
 553         if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
 554             be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
 555                 return -EINVAL;
 556
 557         if (message->dhcp.op != BOOTREPLY)
 558                 return -EINVAL;
 559
 560         if (be32toh(message->dhcp.xid) != client->xid)
 561                 return -EINVAL;
 562
 563         if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
 564                     ETHER_ADDR_LEN))
 565                 return -EINVAL;
 566
 567         return 0;
 568 }
 569
 570 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
 571                                 size_t len)
 572 {
 573         int err;
 574         DHCPLease *lease;
 575
 576         err = client_verify_headers(client, offer, len);
 577         if (err < 0)
 578                 return err;
 579
 580         lease = new0(DHCPLease, 1);
 581         if (!lease)
 582                 return -ENOMEM;
 583
 584         len = len - DHCP_IP_UDP_SIZE;
 585         if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
 586                               lease) != DHCP_OFFER)
 587                 goto error;
 588
 589         lease->address = offer->dhcp.yiaddr;
 590
 591         if (lease->address == INADDR_ANY ||
 592             lease->server_address == INADDR_ANY ||
 593             lease->subnet_mask == INADDR_ANY ||
 594             lease->lifetime == 0)
 595                 goto error;
 596
 597         client->lease = lease;
 598
 599         return 0;
 600
 601 error:
 602         free(lease);
 603
 604         return -ENOMSG;
 605 }
 606
 607 static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
 608                               size_t len)
 609 {
 610         int r;
 611         DHCPLease *lease;
 612
 613         r = client_verify_headers(client, offer, len);
 614         if (r < 0)
 615                 return r;
 616
 617         lease = new0(DHCPLease, 1);
 618         if (!lease)
 619                 return -ENOBUFS;
 620
 621         len = len - DHCP_IP_UDP_SIZE;
 622         r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, lease);
 623
 624         if (r != DHCP_ACK)
 625                 goto error;
 626
 627         lease->address = offer->dhcp.yiaddr;
 628
 629         if (lease->address == INADDR_ANY ||
 630             lease->server_address == INADDR_ANY ||
 631             lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
 632                 r = -ENOMSG;
 633                 goto error;
 634         }
 635
 636         r = DHCP_EVENT_IP_ACQUIRE;
 637         if (client->lease) {
 638                 if (client->lease->address != lease->address ||
 639                     client->lease->subnet_mask != lease->subnet_mask ||
 640                     client->lease->router != lease->router) {
 641                         r = DHCP_EVENT_IP_CHANGE;
 642                 }
 643
 644                 free(client->lease);
 645         }
 646
 647         client->lease = lease;
 648
 649         return r;
 650
 651 error:
 652         free(lease);
 653
 654         return r;
 655 }
 656
 657 static uint64_t client_compute_timeout(uint64_t request_sent,
 658                                        uint32_t lifetime)
 659 {
 660         return request_sent + (lifetime - 3) * USEC_PER_SEC +
 661                 + (random_u() & 0x1fffff);
 662 }
 663
 664 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
 665 {
 666         int err;
 667         uint64_t next_timeout;
 668
 669         if (client->lease->lifetime < 10)
 670                 return -EINVAL;
 671
 672         if (!client->lease->t1)
 673                 client->lease->t1 = client->lease->lifetime / 2;
 674
 675         next_timeout = client_compute_timeout(client->request_sent,
 676                                               client->lease->t1);
 677         if (next_timeout < usec)
 678                 return -EINVAL;
 679
 680         err = sd_event_add_monotonic(client->event, next_timeout,
 681                                      10 * USEC_PER_MSEC,
 682                                      client_timeout_t1, client,
 683                                      &client->timeout_t1);
 684         if (err < 0)
 685                 return err;
 686
 687         if (!client->lease->t2)
 688                 client->lease->t2 = client->lease->lifetime * 7 / 8;
 689
 690         if (client->lease->t2 < client->lease->t1)
 691                 return -EINVAL;
 692
 693         if (client->lease->lifetime < client->lease->t2)
 694                 return -EINVAL;
 695
 696         next_timeout = client_compute_timeout(client->request_sent,
 697                                               client->lease->t2);
 698         if (next_timeout < usec)
 699                 return -EINVAL;
 700
 701         err = sd_event_add_monotonic(client->event, next_timeout,
 702                                      10 * USEC_PER_MSEC,
 703                                      client_timeout_t2, client,
 704                                      &client->timeout_t2);
 705         if (err < 0)
 706                 return err;
 707
 708         next_timeout = client_compute_timeout(client->request_sent,
 709                                               client->lease->lifetime);
 710         if (next_timeout < usec)
 711                 return -EINVAL;
 712
 713         err = sd_event_add_monotonic(client->event, next_timeout,
 714                                      10 * USEC_PER_MSEC,
 715                                      client_timeout_expire, client,
 716                                      &client->timeout_expire);
 717         if (err < 0)
 718                 return err;
 719
 720         return 0;
 721 }
 722
 723 static int client_receive_raw_message(sd_event_source *s, int fd,
 724                                       uint32_t revents, void *userdata)
 725 {
 726         sd_dhcp_client *client = userdata;
 727         uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
 728         int buflen = sizeof(buf);
 729         int len, r = 0;
 730         DHCPPacket *message;
 731         usec_t time_now;
 732
 733         len = read(fd, &buf, buflen);
 734         if (len < 0)
 735                 return 0;
 736
 737         r = sd_event_get_now_monotonic(client->event, &time_now);
 738         if (r < 0)
 739                 goto error;
 740
 741         message = (DHCPPacket *)&buf;
 742
 743         switch (client->state) {
 744         case DHCP_STATE_SELECTING:
 745
 746                 if (client_receive_offer(client, message, len) >= 0) {
 747
 748                         client->timeout_resend =
 749                                 sd_event_source_unref(client->timeout_resend);
 750
 751                         client->state = DHCP_STATE_REQUESTING;
 752                         client->attempt = 1;
 753
 754                         r = sd_event_add_monotonic(client->event, time_now, 0,
 755                                                    client_timeout_resend,
 756                                                    client,
 757                                                    &client->timeout_resend);
 758                         if (r < 0)
 759                                 goto error;
 760                 }
 761
 762                 break;
 763
 764         case DHCP_STATE_REQUESTING:
 765
 766                 r = client_receive_ack(client, message, len);
 767                 if (r == DHCP_EVENT_NO_LEASE)
 768                         goto error;
 769
 770                 if (r >= 0) {
 771                         client->timeout_resend =
 772                                 sd_event_source_unref(client->timeout_resend);
 773
 774                         client->state = DHCP_STATE_BOUND;
 775                         client->attempt = 1;
 776
 777                         client->last_addr = client->lease->address;
 778
 779                         r = client_set_lease_timeouts(client, time_now);
 780                         if (r < 0 )
 781                                 goto error;
 782
 783                         client_notify(client, DHCP_EVENT_IP_ACQUIRE);
 784
 785                         close(client->fd);
 786                         client->fd = -1;
 787                         client->receive_message =
 788                                 sd_event_source_unref(client->receive_message);
 789                 }
 790                 break;
 791
 792         case DHCP_STATE_INIT:
 793         case DHCP_STATE_INIT_REBOOT:
 794         case DHCP_STATE_REBOOTING:
 795         case DHCP_STATE_BOUND:
 796         case DHCP_STATE_RENEWING:
 797         case DHCP_STATE_REBINDING:
 798
 799                 break;
 800         }
 801
 802 error:
 803         if (r < 0)
 804                 return client_stop(client, r);
 805
 806         return 0;
 807 }
 808
 809 int sd_dhcp_client_start(sd_dhcp_client *client)
 810 {
 811         int err;
 812
 813         assert_return(client, -EINVAL);
 814         assert_return(client->index >= 0, -EINVAL);
 815         assert_return(client->state == DHCP_STATE_INIT ||
 816                       client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
 817
 818         client->xid = random_u();
 819
 820         client->fd = dhcp_network_bind_raw_socket(client->index,
 821                                                   &client->link);
 822
 823         if (client->fd < 0) {
 824                 err = client->fd;
 825                 goto error;
 826         }
 827
 828         err = sd_event_add_io(client->event, client->fd, EPOLLIN,
 829                               client_receive_raw_message, client,
 830                               &client->receive_message);
 831         if (err < 0)
 832                 goto error;
 833
 834         client->start_time = now(CLOCK_MONOTONIC);
 835         err = sd_event_add_monotonic(client->event, client->start_time, 0,
 836                                      client_timeout_resend, client,
 837                                      &client->timeout_resend);
 838         if (err < 0)
 839                 goto error;
 840
 841         return 0;
 842
 843 error:
 844         client_stop(client, err);
 845
 846         return err;
 847 }
 848
 849 int sd_dhcp_client_stop(sd_dhcp_client *client)
 850 {
 851         return client_stop(client, 0);
 852 }
 853
 854 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
 855 {
 856         sd_dhcp_client *client;
 857
 858         assert_return(event, NULL);
 859
 860         client = new0(sd_dhcp_client, 1);
 861         if (!client)
 862                 return NULL;
 863
 864         client->event = sd_event_ref(event);
 865         client->state = DHCP_STATE_INIT;
 866         client->index = -1;
 867         client->fd = -1;
 868         client->attempt = 1;
 869
 870         client->req_opts_size = ELEMENTSOF(default_req_opts);
 871
 872         client->req_opts = memdup(default_req_opts, client->req_opts_size);
 873         if (!client->req_opts) {
 874                 free(client);
 875                 return NULL;
 876         }
 877
 878         return client;
 879 }