src/network/networkd-dhcp4.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013-2014 Tom Gundersen <teg@jklm.no>
   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 <netinet/ether.h>
  21 #include <linux/if.h>
  22
  23 #include "alloc-util.h"
  24 #include "dhcp-lease-internal.h"
  25 #include "hostname-util.h"
  26 #include "network-internal.h"
  27 #include "networkd-link.h"
  28
  29 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m,
  30                                void *userdata) {
  31         _cleanup_link_unref_ Link *link = userdata;
  32         int r;
  33
  34         assert(link);
  35         assert(link->dhcp4_messages > 0);
  36
  37         link->dhcp4_messages--;
  38
  39         r = sd_netlink_message_get_errno(m);
  40         if (r < 0 && r != -EEXIST) {
  41                 log_link_error_errno(link, r, "Could not set DHCPv4 route: %m");
  42                 link_enter_failed(link);
  43         }
  44
  45         if (link->dhcp4_messages == 0) {
  46                 link->dhcp4_configured = true;
  47                 link_check_ready(link);
  48         }
  49
  50         return 1;
  51 }
  52
  53 static int link_set_dhcp_routes(Link *link) {
  54         struct in_addr gateway;
  55         _cleanup_free_ sd_dhcp_route **static_routes = NULL;
  56         int r, n, i;
  57
  58         assert(link);
  59         assert(link->dhcp_lease);
  60         assert(link->network);
  61
  62         if (!link->network->dhcp_use_routes)
  63                 return 0;
  64
  65         r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
  66         if (r < 0 && r != -ENODATA)
  67                 return log_link_warning_errno(link, r, "DHCP error: could not get gateway: %m");
  68
  69         if (r >= 0) {
  70                 struct in_addr address;
  71                 _cleanup_route_free_ Route *route = NULL;
  72                 _cleanup_route_free_ Route *route_gw = NULL;
  73
  74                 r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
  75                 if (r < 0)
  76                         return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
  77
  78                 r = route_new(&route);
  79                 if (r < 0)
  80                         return log_link_error_errno(link, r, "Could not allocate route: %m");
  81
  82                 route->protocol = RTPROT_DHCP;
  83
  84                 r = route_new(&route_gw);
  85                 if (r < 0)
  86                         return log_link_error_errno(link, r,  "Could not allocate route: %m");
  87
  88                 /* The dhcp netmask may mask out the gateway. Add an explicit
  89                  * route for the gw host so that we can route no matter the
  90                  * netmask or existing kernel route tables. */
  91                 route_gw->family = AF_INET;
  92                 route_gw->dst.in = gateway;
  93                 route_gw->dst_prefixlen = 32;
  94                 route_gw->prefsrc.in = address;
  95                 route_gw->scope = RT_SCOPE_LINK;
  96                 route_gw->protocol = RTPROT_DHCP;
  97                 route_gw->priority = link->network->dhcp_route_metric;
  98
  99                 r = route_configure(route_gw, link, &dhcp4_route_handler);
 100                 if (r < 0)
 101                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 102
 103                 link->dhcp4_messages++;
 104
 105                 route->family = AF_INET;
 106                 route->gw.in = gateway;
 107                 route->prefsrc.in = address;
 108                 route->priority = link->network->dhcp_route_metric;
 109
 110                 r = route_configure(route, link, &dhcp4_route_handler);
 111                 if (r < 0) {
 112                         log_link_warning_errno(link, r, "Could not set routes: %m");
 113                         link_enter_failed(link);
 114                         return r;
 115                 }
 116
 117                 link->dhcp4_messages++;
 118         }
 119
 120         n = sd_dhcp_lease_get_routes(link->dhcp_lease, &static_routes);
 121         if (n == -ENODATA)
 122                 return 0;
 123         if (n < 0)
 124                 return log_link_warning_errno(link, n, "DHCP error: could not get routes: %m");
 125
 126         for (i = 0; i < n; i++) {
 127                 _cleanup_route_free_ Route *route = NULL;
 128
 129                 r = route_new(&route);
 130                 if (r < 0)
 131                         return log_link_error_errno(link, r, "Could not allocate route: %m");
 132
 133                 route->family = AF_INET;
 134                 route->protocol = RTPROT_DHCP;
 135                 assert_se(sd_dhcp_route_get_gateway(static_routes[i], &route->gw.in) >= 0);
 136                 assert_se(sd_dhcp_route_get_destination(static_routes[i], &route->dst.in) >= 0);
 137                 assert_se(sd_dhcp_route_get_destination_prefix_length(static_routes[i], &route->dst_prefixlen) >= 0);
 138                 route->priority = link->network->dhcp_route_metric;
 139
 140                 r = route_configure(route, link, &dhcp4_route_handler);
 141                 if (r < 0)
 142                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 143
 144                 link->dhcp4_messages++;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int dhcp_lease_lost(Link *link) {
 151         _cleanup_address_free_ Address *address = NULL;
 152         struct in_addr addr;
 153         struct in_addr netmask;
 154         struct in_addr gateway;
 155         unsigned prefixlen = 0;
 156         int r;
 157
 158         assert(link);
 159         assert(link->dhcp_lease);
 160
 161         log_link_warning(link, "DHCP lease lost");
 162
 163         if (link->network->dhcp_use_routes) {
 164                 _cleanup_free_ sd_dhcp_route **routes = NULL;
 165                 int n, i;
 166
 167                 n = sd_dhcp_lease_get_routes(link->dhcp_lease, &routes);
 168                 if (n >= 0) {
 169                         for (i = 0; i < n; i++) {
 170                                 _cleanup_route_free_ Route *route = NULL;
 171
 172                                 r = route_new(&route);
 173                                 if (r >= 0) {
 174                                         route->family = AF_INET;
 175                                         assert_se(sd_dhcp_route_get_gateway(routes[i], &route->gw.in) >= 0);
 176                                         assert_se(sd_dhcp_route_get_destination(routes[i], &route->dst.in) >= 0);
 177                                         assert_se(sd_dhcp_route_get_destination_prefix_length(routes[i], &route->dst_prefixlen) >= 0);
 178
 179                                         route_remove(route, link,
 180                                                    &link_route_remove_handler);
 181                                 }
 182                         }
 183                 }
 184         }
 185
 186         r = address_new(&address);
 187         if (r >= 0) {
 188                 r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
 189                 if (r >= 0) {
 190                         _cleanup_route_free_ Route *route_gw = NULL;
 191                         _cleanup_route_free_ Route *route = NULL;
 192
 193                         r = route_new(&route_gw);
 194                         if (r >= 0) {
 195                                 route_gw->family = AF_INET;
 196                                 route_gw->dst.in = gateway;
 197                                 route_gw->dst_prefixlen = 32;
 198                                 route_gw->scope = RT_SCOPE_LINK;
 199
 200                                 route_remove(route_gw, link,
 201                                            &link_route_remove_handler);
 202                         }
 203
 204                         r = route_new(&route);
 205                         if (r >= 0) {
 206                                 route->family = AF_INET;
 207                                 route->gw.in = gateway;
 208
 209                                 route_remove(route, link,
 210                                            &link_route_remove_handler);
 211                         }
 212                 }
 213
 214                 r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr);
 215                 if (r >= 0) {
 216                         r = sd_dhcp_lease_get_netmask(link->dhcp_lease, &netmask);
 217                         if (r >= 0)
 218                                 prefixlen = in_addr_netmask_to_prefixlen(&netmask);
 219
 220                         address->family = AF_INET;
 221                         address->in_addr.in = addr;
 222                         address->prefixlen = prefixlen;
 223
 224                         address_remove(address, link, &link_address_remove_handler);
 225                 }
 226         }
 227
 228         if (link->network->dhcp_use_mtu) {
 229                 uint16_t mtu;
 230
 231                 r = sd_dhcp_lease_get_mtu(link->dhcp_lease, &mtu);
 232                 if (r >= 0 && link->original_mtu != mtu) {
 233                         r = link_set_mtu(link, link->original_mtu);
 234                         if (r < 0) {
 235                                 log_link_warning(link,
 236                                                  "DHCP error: could not reset MTU");
 237                                 link_enter_failed(link);
 238                                 return r;
 239                         }
 240                 }
 241         }
 242
 243         if (link->network->dhcp_use_hostname) {
 244                 const char *hostname = NULL;
 245
 246                 if (link->network->dhcp_hostname)
 247                         hostname = link->network->dhcp_hostname;
 248                 else
 249                         (void) sd_dhcp_lease_get_hostname(link->dhcp_lease, &hostname);
 250
 251                 if (hostname) {
 252                         /* If a hostname was set due to the lease, then unset it now. */
 253                         r = link_set_hostname(link, NULL);
 254                         if (r < 0)
 255                                 log_link_warning_errno(link, r, "Failed to reset transient hostname: %m");
 256                 }
 257         }
 258
 259         link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
 260         link_dirty(link);
 261         link->dhcp4_configured = false;
 262
 263         return 0;
 264 }
 265
 266 static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m,
 267                                  void *userdata) {
 268         _cleanup_link_unref_ Link *link = userdata;
 269         int r;
 270
 271         assert(link);
 272
 273         r = sd_netlink_message_get_errno(m);
 274         if (r < 0 && r != -EEXIST) {
 275                 log_link_error_errno(link, r, "Could not set DHCPv4 address: %m");
 276                 link_enter_failed(link);
 277         } else if (r >= 0)
 278                 manager_rtnl_process_address(rtnl, m, link->manager);
 279
 280         link_set_dhcp_routes(link);
 281
 282         return 1;
 283 }
 284
 285 static int dhcp4_update_address(Link *link,
 286                                 struct in_addr *address,
 287                                 struct in_addr *netmask,
 288                                 uint32_t lifetime) {
 289         _cleanup_address_free_ Address *addr = NULL;
 290         unsigned prefixlen;
 291         int r;
 292
 293         assert(address);
 294         assert(netmask);
 295         assert(lifetime);
 296
 297         prefixlen = in_addr_netmask_to_prefixlen(netmask);
 298
 299         r = address_new(&addr);
 300         if (r < 0)
 301                 return r;
 302
 303         addr->family = AF_INET;
 304         addr->in_addr.in.s_addr = address->s_addr;
 305         addr->cinfo.ifa_prefered = lifetime;
 306         addr->cinfo.ifa_valid = lifetime;
 307         addr->prefixlen = prefixlen;
 308         addr->broadcast.s_addr = address->s_addr | ~netmask->s_addr;
 309
 310         /* allow reusing an existing address and simply update its lifetime
 311          * in case it already exists */
 312         r = address_configure(addr, link, &dhcp4_address_handler, true);
 313         if (r < 0)
 314                 return r;
 315
 316         return 0;
 317 }
 318
 319 static int dhcp_lease_renew(sd_dhcp_client *client, Link *link) {
 320         sd_dhcp_lease *lease;
 321         struct in_addr address;
 322         struct in_addr netmask;
 323         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 324         int r;
 325
 326         assert(link);
 327         assert(client);
 328         assert(link->network);
 329
 330         r = sd_dhcp_client_get_lease(client, &lease);
 331         if (r < 0)
 332                 return log_link_warning_errno(link, r, "DHCP error: no lease: %m");
 333
 334         sd_dhcp_lease_unref(link->dhcp_lease);
 335         link->dhcp4_configured = false;
 336         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 337         link_dirty(link);
 338
 339         r = sd_dhcp_lease_get_address(lease, &address);
 340         if (r < 0)
 341                 return log_link_warning_errno(link, r, "DHCP error: no address: %m");
 342
 343         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 344         if (r < 0)
 345                 return log_link_warning_errno(link, r, "DHCP error: no netmask: %m");
 346
 347         if (!link->network->dhcp_critical) {
 348                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 349                 if (r < 0)
 350                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 351         }
 352
 353         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 354         if (r < 0) {
 355                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 356                 link_enter_failed(link);
 357                 return r;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static int dhcp_lease_acquired(sd_dhcp_client *client, Link *link) {
 364         sd_dhcp_lease *lease;
 365         struct in_addr address;
 366         struct in_addr netmask;
 367         struct in_addr gateway;
 368         unsigned prefixlen;
 369         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 370         int r;
 371
 372         assert(client);
 373         assert(link);
 374
 375         r = sd_dhcp_client_get_lease(client, &lease);
 376         if (r < 0)
 377                 return log_link_error_errno(link, r, "DHCP error: No lease: %m");
 378
 379         r = sd_dhcp_lease_get_address(lease, &address);
 380         if (r < 0)
 381                 return log_link_error_errno(link, r, "DHCP error: No address: %m");
 382
 383         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 384         if (r < 0)
 385                 return log_link_error_errno(link, r, "DHCP error: No netmask: %m");
 386
 387         prefixlen = in_addr_netmask_to_prefixlen(&netmask);
 388
 389         r = sd_dhcp_lease_get_router(lease, &gateway);
 390         if (r < 0 && r != -ENODATA)
 391                 return log_link_error_errno(link, r, "DHCP error: Could not get gateway: %m");
 392
 393         if (r >= 0)
 394                 log_struct(LOG_INFO,
 395                            LOG_LINK_INTERFACE(link),
 396                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
 397                                             ADDRESS_FMT_VAL(address),
 398                                             prefixlen,
 399                                             ADDRESS_FMT_VAL(gateway)),
 400                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 401                            "PREFIXLEN=%u", prefixlen,
 402                            "GATEWAY=%u.%u.%u.%u", ADDRESS_FMT_VAL(gateway),
 403                            NULL);
 404         else
 405                 log_struct(LOG_INFO,
 406                            LOG_LINK_INTERFACE(link),
 407                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u",
 408                                             ADDRESS_FMT_VAL(address),
 409                                             prefixlen),
 410                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 411                            "PREFIXLEN=%u", prefixlen,
 412                            NULL);
 413
 414         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 415         link_dirty(link);
 416
 417         if (link->network->dhcp_use_mtu) {
 418                 uint16_t mtu;
 419
 420                 r = sd_dhcp_lease_get_mtu(lease, &mtu);
 421                 if (r >= 0) {
 422                         r = link_set_mtu(link, mtu);
 423                         if (r < 0)
 424                                 log_link_error_errno(link, r, "Failed to set MTU to %" PRIu16 ": %m", mtu);
 425                 }
 426         }
 427
 428         if (link->network->dhcp_use_hostname) {
 429                 const char *hostname = NULL;
 430
 431                 if (link->network->dhcp_hostname)
 432                         hostname = link->network->dhcp_hostname;
 433                 else
 434                         (void) sd_dhcp_lease_get_hostname(lease, &hostname);
 435
 436                 if (hostname) {
 437                         r = link_set_hostname(link, hostname);
 438                         if (r < 0)
 439                                 log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
 440                 }
 441         }
 442
 443         if (link->network->dhcp_use_timezone) {
 444                 const char *tz = NULL;
 445
 446                 (void) sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
 447
 448                 if (tz) {
 449                         r = link_set_timezone(link, tz);
 450                         if (r < 0)
 451                                 log_link_error_errno(link, r, "Failed to set timezone to '%s': %m", tz);
 452                 }
 453         }
 454
 455         if (!link->network->dhcp_critical) {
 456                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 457                 if (r < 0) {
 458                         log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 459                         return r;
 460                 }
 461         }
 462
 463         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 464         if (r < 0) {
 465                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 466                 link_enter_failed(link);
 467                 return r;
 468         }
 469
 470         return 0;
 471 }
 472 static void dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
 473         Link *link = userdata;
 474         int r = 0;
 475
 476         assert(link);
 477         assert(link->network);
 478         assert(link->manager);
 479
 480         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 481                 return;
 482
 483         switch (event) {
 484                 case SD_DHCP_CLIENT_EVENT_EXPIRED:
 485                 case SD_DHCP_CLIENT_EVENT_STOP:
 486                 case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
 487                         if (link->network->dhcp_critical) {
 488                                 log_link_error(link, "DHCPv4 connection considered system critical, ignoring request to reconfigure it.");
 489                                 return;
 490                         }
 491
 492                         if (link->dhcp_lease) {
 493                                 r = dhcp_lease_lost(link);
 494                                 if (r < 0) {
 495                                         link_enter_failed(link);
 496                                         return;
 497                                 }
 498                         }
 499
 500                         if (event == SD_DHCP_CLIENT_EVENT_IP_CHANGE) {
 501                                 r = dhcp_lease_acquired(client, link);
 502                                 if (r < 0) {
 503                                         link_enter_failed(link);
 504                                         return;
 505                                 }
 506                         }
 507
 508                         break;
 509                 case SD_DHCP_CLIENT_EVENT_RENEW:
 510                         r = dhcp_lease_renew(client, link);
 511                         if (r < 0) {
 512                                 link_enter_failed(link);
 513                                 return;
 514                         }
 515                         break;
 516                 case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
 517                         r = dhcp_lease_acquired(client, link);
 518                         if (r < 0) {
 519                                 link_enter_failed(link);
 520                                 return;
 521                         }
 522                         break;
 523                 default:
 524                         if (event < 0)
 525                                 log_link_warning_errno(link, event, "DHCP error: Client failed: %m");
 526                         else
 527                                 log_link_warning(link, "DHCP unknown event: %i", event);
 528                         break;
 529         }
 530
 531         return;
 532 }
 533
 534 int dhcp4_configure(Link *link) {
 535         int r;
 536
 537         assert(link);
 538         assert(link->network);
 539         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 540
 541         if (!link->dhcp_client) {
 542                 r = sd_dhcp_client_new(&link->dhcp_client);
 543                 if (r < 0)
 544                         return r;
 545         }
 546
 547         r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
 548         if (r < 0)
 549                 return r;
 550
 551         r = sd_dhcp_client_set_mac(link->dhcp_client,
 552                                    (const uint8_t *) &link->mac,
 553                                    sizeof (link->mac), ARPHRD_ETHER);
 554         if (r < 0)
 555                 return r;
 556
 557         r = sd_dhcp_client_set_index(link->dhcp_client, link->ifindex);
 558         if (r < 0)
 559                 return r;
 560
 561         r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp4_handler, link);
 562         if (r < 0)
 563                 return r;
 564
 565         r = sd_dhcp_client_set_request_broadcast(link->dhcp_client,
 566                                                  link->network->dhcp_broadcast);
 567         if (r < 0)
 568                 return r;
 569
 570         if (link->mtu) {
 571                 r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
 572                 if (r < 0)
 573                         return r;
 574         }
 575
 576         if (link->network->dhcp_use_mtu) {
 577                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 578                                                       SD_DHCP_OPTION_INTERFACE_MTU);
 579                 if (r < 0)
 580                         return r;
 581         }
 582
 583         if (link->network->dhcp_use_routes) {
 584                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 585                                                       SD_DHCP_OPTION_STATIC_ROUTE);
 586                 if (r < 0)
 587                         return r;
 588                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 589                                                       SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE);
 590                 if (r < 0)
 591                         return r;
 592         }
 593
 594         /* Always acquire the timezone and NTP */
 595         r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NTP_SERVER);
 596         if (r < 0)
 597                 return r;
 598
 599         r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NEW_TZDB_TIMEZONE);
 600         if (r < 0)
 601                 return r;
 602
 603         if (link->network->dhcp_send_hostname) {
 604                 _cleanup_free_ char *hostname = NULL;
 605                 const char *hn = NULL;
 606
 607                 if (!link->network->dhcp_hostname) {
 608                         hostname = gethostname_malloc();
 609                         if (!hostname)
 610                                 return -ENOMEM;
 611
 612                         hn = hostname;
 613                 } else
 614                         hn = link->network->dhcp_hostname;
 615
 616                 if (!is_localhost(hn)) {
 617                         r = sd_dhcp_client_set_hostname(link->dhcp_client, hn);
 618                         if (r < 0)
 619                                 return r;
 620                 }
 621         }
 622
 623         if (link->network->dhcp_vendor_class_identifier) {
 624                 r = sd_dhcp_client_set_vendor_class_identifier(link->dhcp_client,
 625                                                                link->network->dhcp_vendor_class_identifier);
 626                 if (r < 0)
 627                         return r;
 628         }
 629
 630         switch (link->network->dhcp_client_identifier) {
 631         case DHCP_CLIENT_ID_DUID:
 632                 /* If configured, apply user specified DUID and/or IAID */
 633                 if (link->network->duid_type != _DUID_TYPE_INVALID)
 634                         r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
 635                                                          link->network->iaid,
 636                                                          link->network->dhcp_duid_type,
 637                                                          link->network->dhcp_duid,
 638                                                          link->network->dhcp_duid_len);
 639                 else
 640                         r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
 641                                                          link->network->iaid,
 642                                                          link->manager->dhcp_duid_type,
 643                                                          link->manager->dhcp_duid,
 644                                                          link->manager->dhcp_duid_len);
 645                 if (r < 0)
 646                         return r;
 647                 break;
 648         case DHCP_CLIENT_ID_MAC:
 649                 r = sd_dhcp_client_set_client_id(link->dhcp_client,
 650                                                  ARPHRD_ETHER,
 651                                                  (const uint8_t *) &link->mac,
 652                                                  sizeof (link->mac));
 653                 if (r < 0)
 654                         return r;
 655                 break;
 656         default:
 657                 assert_not_reached("Unknown client identifier type.");
 658         }
 659
 660         return 0;
 661 }