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