src/network/networkd-dhcp4.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <netinet/ether.h>
   4 #include <linux/if.h>
   5
   6 #include "alloc-util.h"
   7 #include "hostname-util.h"
   8 #include "parse-util.h"
   9 #include "network-internal.h"
  10 #include "networkd-link.h"
  11 #include "networkd-manager.h"
  12 #include "networkd-network.h"
  13 #include "string-util.h"
  14 #include "sysctl-util.h"
  15
  16 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
  17         int r;
  18
  19         assert(link);
  20         assert(link->dhcp4_messages > 0);
  21
  22         link->dhcp4_messages--;
  23
  24         r = sd_netlink_message_get_errno(m);
  25         if (r < 0 && r != -EEXIST) {
  26                 log_link_error_errno(link, r, "Could not set DHCPv4 route: %m");
  27                 link_enter_failed(link);
  28         }
  29
  30         if (link->dhcp4_messages == 0) {
  31                 link->dhcp4_configured = true;
  32                 link_check_ready(link);
  33         }
  34
  35         return 1;
  36 }
  37
  38 static int route_scope_from_address(const Route *route, const struct in_addr *self_addr) {
  39         assert(route);
  40         assert(self_addr);
  41
  42         if (in_addr_is_localhost(AF_INET, &route->dst) ||
  43             (self_addr->s_addr && route->dst.in.s_addr == self_addr->s_addr))
  44                 return RT_SCOPE_HOST;
  45         else if (in4_addr_is_null(&route->gw.in))
  46                 return RT_SCOPE_LINK;
  47         else
  48                 return RT_SCOPE_UNIVERSE;
  49 }
  50
  51 static int link_set_dhcp_routes(Link *link) {
  52         _cleanup_free_ sd_dhcp_route **static_routes = NULL;
  53         bool classless_route = false, static_route = false;
  54         const struct in_addr *router;
  55         struct in_addr address;
  56         int r, n, i;
  57         uint32_t table;
  58
  59         assert(link);
  60
  61         if (!link->dhcp_lease) /* link went down while we configured the IP addresses? */
  62                 return 0;
  63
  64         if (!link->network) /* link went down while we configured the IP addresses? */
  65                 return 0;
  66
  67         if (!link->network->dhcp_use_routes)
  68                 return 0;
  69
  70         table = link_get_dhcp_route_table(link);
  71
  72         r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
  73         if (r < 0)
  74                 return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
  75
  76         n = sd_dhcp_lease_get_routes(link->dhcp_lease, &static_routes);
  77         if (n == -ENODATA)
  78                 log_link_debug_errno(link, n, "DHCP: No routes received from DHCP server: %m");
  79         else if (n < 0)
  80                 log_link_debug_errno(link, n, "DHCP error: could not get routes: %m");
  81
  82         for (i = 0; i < n; i++) {
  83                 switch (sd_dhcp_route_get_option(static_routes[i])) {
  84                 case SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE:
  85                         classless_route = true;
  86                         break;
  87                 case SD_DHCP_OPTION_STATIC_ROUTE:
  88                         static_route = true;
  89                         break;
  90                 }
  91         }
  92
  93         for (i = 0; i < n; i++) {
  94                 _cleanup_(route_freep) Route *route = NULL;
  95
  96                 /* if the DHCP server returns both a Classless Static Routes option and a Static Routes option,
  97                    the DHCP client MUST ignore the Static Routes option. */
  98                 if (classless_route &&
  99                     sd_dhcp_route_get_option(static_routes[i]) != SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE)
 100                         continue;
 101
 102                 r = route_new(&route);
 103                 if (r < 0)
 104                         return log_link_error_errno(link, r, "Could not allocate route: %m");
 105
 106                 route->family = AF_INET;
 107                 route->protocol = RTPROT_DHCP;
 108                 assert_se(sd_dhcp_route_get_gateway(static_routes[i], &route->gw.in) >= 0);
 109                 assert_se(sd_dhcp_route_get_destination(static_routes[i], &route->dst.in) >= 0);
 110                 assert_se(sd_dhcp_route_get_destination_prefix_length(static_routes[i], &route->dst_prefixlen) >= 0);
 111                 route->priority = link->network->dhcp_route_metric;
 112                 route->table = table;
 113                 route->scope = route_scope_from_address(route, &address);
 114
 115                 r = route_configure(route, link, dhcp4_route_handler);
 116                 if (r < 0)
 117                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 118
 119                 link->dhcp4_messages++;
 120         }
 121
 122         r = sd_dhcp_lease_get_router(link->dhcp_lease, &router);
 123         if (IN_SET(r, 0, -ENODATA))
 124                 log_link_info(link, "DHCP: No gateway received from DHCP server.");
 125         else if (r < 0)
 126                 log_link_warning_errno(link, r, "DHCP error: could not get gateway: %m");
 127         else if (in4_addr_is_null(&router[0]))
 128                 log_link_info(link, "DHCP: Received gateway is null.");
 129
 130         /* According to RFC 3442: If the DHCP server returns both a Classless Static Routes option and
 131            a Router option, the DHCP client MUST ignore the Router option. */
 132         if (classless_route && static_route)
 133                 log_link_warning(link, "Classless static routes received from DHCP server: ignoring static-route option and router option");
 134
 135         if (r > 0 && !classless_route && !in4_addr_is_null(&router[0])) {
 136                 _cleanup_(route_freep) Route *route = NULL, *route_gw = NULL;
 137
 138                 r = route_new(&route_gw);
 139                 if (r < 0)
 140                         return log_link_error_errno(link, r,  "Could not allocate route: %m");
 141
 142                 /* The dhcp netmask may mask out the gateway. Add an explicit
 143                  * route for the gw host so that we can route no matter the
 144                  * netmask or existing kernel route tables. */
 145                 route_gw->family = AF_INET;
 146                 route_gw->dst.in = router[0];
 147                 route_gw->dst_prefixlen = 32;
 148                 route_gw->prefsrc.in = address;
 149                 route_gw->scope = RT_SCOPE_LINK;
 150                 route_gw->protocol = RTPROT_DHCP;
 151                 route_gw->priority = link->network->dhcp_route_metric;
 152                 route_gw->table = table;
 153
 154                 r = route_configure(route_gw, link, dhcp4_route_handler);
 155                 if (r < 0)
 156                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 157
 158                 link->dhcp4_messages++;
 159
 160                 r = route_new(&route);
 161                 if (r < 0)
 162                         return log_link_error_errno(link, r, "Could not allocate route: %m");
 163
 164                 route->family = AF_INET;
 165                 route->gw.in = router[0];
 166                 route->prefsrc.in = address;
 167                 route->protocol = RTPROT_DHCP;
 168                 route->priority = link->network->dhcp_route_metric;
 169                 route->table = table;
 170
 171                 r = route_configure(route, link, dhcp4_route_handler);
 172                 if (r < 0) {
 173                         log_link_warning_errno(link, r, "Could not set routes: %m");
 174                         link_enter_failed(link);
 175                         return r;
 176                 }
 177
 178                 link->dhcp4_messages++;
 179         }
 180
 181         return 0;
 182 }
 183
 184 static int dhcp_lease_lost(Link *link) {
 185         _cleanup_(address_freep) Address *address = NULL;
 186         const struct in_addr *router;
 187         struct in_addr addr;
 188         struct in_addr netmask;
 189         unsigned prefixlen = 0;
 190         int r;
 191
 192         assert(link);
 193         assert(link->dhcp_lease);
 194
 195         log_link_warning(link, "DHCP lease lost");
 196
 197         if (link->network->dhcp_use_routes) {
 198                 _cleanup_free_ sd_dhcp_route **routes = NULL;
 199                 int n, i;
 200
 201                 n = sd_dhcp_lease_get_routes(link->dhcp_lease, &routes);
 202                 if (n >= 0) {
 203                         for (i = 0; i < n; i++) {
 204                                 _cleanup_(route_freep) Route *route = NULL;
 205
 206                                 r = route_new(&route);
 207                                 if (r >= 0) {
 208                                         route->family = AF_INET;
 209                                         assert_se(sd_dhcp_route_get_gateway(routes[i], &route->gw.in) >= 0);
 210                                         assert_se(sd_dhcp_route_get_destination(routes[i], &route->dst.in) >= 0);
 211                                         assert_se(sd_dhcp_route_get_destination_prefix_length(routes[i], &route->dst_prefixlen) >= 0);
 212
 213                                         route_remove(route, link, NULL);
 214                                 }
 215                         }
 216                 }
 217         }
 218
 219         r = address_new(&address);
 220         if (r >= 0) {
 221                 r = sd_dhcp_lease_get_router(link->dhcp_lease, &router);
 222                 if (r > 0 && !in4_addr_is_null(&router[0])) {
 223                         _cleanup_(route_freep) Route *route_gw = NULL;
 224                         _cleanup_(route_freep) Route *route = NULL;
 225
 226                         r = route_new(&route_gw);
 227                         if (r >= 0) {
 228                                 route_gw->family = AF_INET;
 229                                 route_gw->dst.in = router[0];
 230                                 route_gw->dst_prefixlen = 32;
 231                                 route_gw->scope = RT_SCOPE_LINK;
 232
 233                                 route_remove(route_gw, link, NULL);
 234                         }
 235
 236                         r = route_new(&route);
 237                         if (r >= 0) {
 238                                 route->family = AF_INET;
 239                                 route->gw.in = router[0];
 240
 241                                 route_remove(route, link, NULL);
 242                         }
 243                 }
 244
 245                 r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr);
 246                 if (r >= 0) {
 247                         r = sd_dhcp_lease_get_netmask(link->dhcp_lease, &netmask);
 248                         if (r >= 0)
 249                                 prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 250
 251                         address->family = AF_INET;
 252                         address->in_addr.in = addr;
 253                         address->prefixlen = prefixlen;
 254
 255                         address_remove(address, link, NULL);
 256                 }
 257         }
 258
 259         if (link->network->dhcp_use_mtu) {
 260                 uint16_t mtu;
 261
 262                 r = sd_dhcp_lease_get_mtu(link->dhcp_lease, &mtu);
 263                 if (r >= 0 && link->original_mtu != mtu) {
 264                         r = link_set_mtu(link, link->original_mtu);
 265                         if (r < 0) {
 266                                 log_link_warning(link,
 267                                                  "DHCP error: could not reset MTU");
 268                                 link_enter_failed(link);
 269                                 return r;
 270                         }
 271                 }
 272         }
 273
 274         if (link->network->dhcp_use_hostname) {
 275                 const char *hostname = NULL;
 276
 277                 if (link->network->dhcp_hostname)
 278                         hostname = link->network->dhcp_hostname;
 279                 else
 280                         (void) sd_dhcp_lease_get_hostname(link->dhcp_lease, &hostname);
 281
 282                 if (hostname) {
 283                         /* If a hostname was set due to the lease, then unset it now. */
 284                         r = manager_set_hostname(link->manager, NULL);
 285                         if (r < 0)
 286                                 log_link_warning_errno(link, r, "Failed to reset transient hostname: %m");
 287                 }
 288         }
 289
 290         link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
 291         link_dirty(link);
 292         link->dhcp4_configured = false;
 293
 294         return 0;
 295 }
 296
 297 static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
 298         int r;
 299
 300         assert(link);
 301
 302         r = sd_netlink_message_get_errno(m);
 303         if (r < 0 && r != -EEXIST) {
 304                 log_link_error_errno(link, r, "Could not set DHCPv4 address: %m");
 305                 link_enter_failed(link);
 306         } else if (r >= 0)
 307                 manager_rtnl_process_address(rtnl, m, link->manager);
 308
 309         link_set_dhcp_routes(link);
 310
 311         if (link->dhcp4_messages == 0) {
 312                 link->dhcp4_configured = true;
 313                 link_check_ready(link);
 314         }
 315
 316         return 1;
 317 }
 318
 319 static int dhcp4_update_address(Link *link,
 320                                 struct in_addr *address,
 321                                 struct in_addr *netmask,
 322                                 uint32_t lifetime) {
 323         _cleanup_(address_freep) Address *addr = NULL;
 324         unsigned prefixlen;
 325         int r;
 326
 327         assert(address);
 328         assert(netmask);
 329         assert(lifetime);
 330
 331         prefixlen = in4_addr_netmask_to_prefixlen(netmask);
 332
 333         r = address_new(&addr);
 334         if (r < 0)
 335                 return r;
 336
 337         addr->family = AF_INET;
 338         addr->in_addr.in.s_addr = address->s_addr;
 339         addr->cinfo.ifa_prefered = lifetime;
 340         addr->cinfo.ifa_valid = lifetime;
 341         addr->prefixlen = prefixlen;
 342         addr->broadcast.s_addr = address->s_addr | ~netmask->s_addr;
 343
 344         /* allow reusing an existing address and simply update its lifetime
 345          * in case it already exists */
 346         r = address_configure(addr, link, dhcp4_address_handler, true);
 347         if (r < 0)
 348                 return r;
 349
 350         return 0;
 351 }
 352
 353 static int dhcp_lease_renew(sd_dhcp_client *client, Link *link) {
 354         sd_dhcp_lease *lease;
 355         struct in_addr address;
 356         struct in_addr netmask;
 357         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 358         int r;
 359
 360         assert(link);
 361         assert(client);
 362         assert(link->network);
 363
 364         r = sd_dhcp_client_get_lease(client, &lease);
 365         if (r < 0)
 366                 return log_link_warning_errno(link, r, "DHCP error: no lease: %m");
 367
 368         sd_dhcp_lease_unref(link->dhcp_lease);
 369         link->dhcp4_configured = false;
 370         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 371         link_dirty(link);
 372
 373         r = sd_dhcp_lease_get_address(lease, &address);
 374         if (r < 0)
 375                 return log_link_warning_errno(link, r, "DHCP error: no address: %m");
 376
 377         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 378         if (r < 0)
 379                 return log_link_warning_errno(link, r, "DHCP error: no netmask: %m");
 380
 381         if (!link->network->dhcp_critical) {
 382                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 383                 if (r < 0)
 384                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 385         }
 386
 387         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 388         if (r < 0) {
 389                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 390                 link_enter_failed(link);
 391                 return r;
 392         }
 393
 394         return 0;
 395 }
 396
 397 static int dhcp_lease_acquired(sd_dhcp_client *client, Link *link) {
 398         const struct in_addr *router;
 399         sd_dhcp_lease *lease;
 400         struct in_addr address;
 401         struct in_addr netmask;
 402         unsigned prefixlen;
 403         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 404         int r;
 405
 406         assert(client);
 407         assert(link);
 408
 409         r = sd_dhcp_client_get_lease(client, &lease);
 410         if (r < 0)
 411                 return log_link_error_errno(link, r, "DHCP error: No lease: %m");
 412
 413         r = sd_dhcp_lease_get_address(lease, &address);
 414         if (r < 0)
 415                 return log_link_error_errno(link, r, "DHCP error: No address: %m");
 416
 417         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 418         if (r < 0)
 419                 return log_link_error_errno(link, r, "DHCP error: No netmask: %m");
 420
 421         prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 422
 423         r = sd_dhcp_lease_get_router(lease, &router);
 424         if (r < 0 && r != -ENODATA)
 425                 return log_link_error_errno(link, r, "DHCP error: Could not get gateway: %m");
 426
 427         if (r > 0 && !in4_addr_is_null(&router[0]))
 428                 log_struct(LOG_INFO,
 429                            LOG_LINK_INTERFACE(link),
 430                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
 431                                             ADDRESS_FMT_VAL(address),
 432                                             prefixlen,
 433                                             ADDRESS_FMT_VAL(router[0])),
 434                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 435                            "PREFIXLEN=%u", prefixlen,
 436                            "GATEWAY=%u.%u.%u.%u", ADDRESS_FMT_VAL(router[0]));
 437         else
 438                 log_struct(LOG_INFO,
 439                            LOG_LINK_INTERFACE(link),
 440                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u",
 441                                             ADDRESS_FMT_VAL(address),
 442                                             prefixlen),
 443                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 444                            "PREFIXLEN=%u", prefixlen);
 445
 446         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 447         link_dirty(link);
 448
 449         if (link->network->dhcp_use_mtu) {
 450                 uint16_t mtu;
 451
 452                 r = sd_dhcp_lease_get_mtu(lease, &mtu);
 453                 if (r >= 0) {
 454                         r = link_set_mtu(link, mtu);
 455                         if (r < 0)
 456                                 log_link_error_errno(link, r, "Failed to set MTU to %" PRIu16 ": %m", mtu);
 457                 }
 458         }
 459
 460         if (link->network->dhcp_use_hostname) {
 461                 const char *dhcpname = NULL;
 462                 _cleanup_free_ char *hostname = NULL;
 463
 464                 if (link->network->dhcp_hostname)
 465                         dhcpname = link->network->dhcp_hostname;
 466                 else
 467                         (void) sd_dhcp_lease_get_hostname(lease, &dhcpname);
 468
 469                 if (dhcpname) {
 470                         r = shorten_overlong(dhcpname, &hostname);
 471                         if (r < 0)
 472                                 log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s', ignoring: %m", dhcpname);
 473                         if (r == 1)
 474                                 log_link_notice(link, "Overlong DCHP hostname received, shortened from '%s' to '%s'", dhcpname, hostname);
 475                 }
 476
 477                 if (hostname) {
 478                         r = manager_set_hostname(link->manager, hostname);
 479                         if (r < 0)
 480                                 log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
 481                 }
 482         }
 483
 484         if (link->network->dhcp_use_timezone) {
 485                 const char *tz = NULL;
 486
 487                 (void) sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
 488
 489                 if (tz) {
 490                         r = manager_set_timezone(link->manager, tz);
 491                         if (r < 0)
 492                                 log_link_error_errno(link, r, "Failed to set timezone to '%s': %m", tz);
 493                 }
 494         }
 495
 496         if (!link->network->dhcp_critical) {
 497                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 498                 if (r < 0)
 499                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 500         }
 501
 502         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 503         if (r < 0) {
 504                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 505                 link_enter_failed(link);
 506                 return r;
 507         }
 508
 509         return 0;
 510 }
 511 static void dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
 512         Link *link = userdata;
 513         int r = 0;
 514
 515         assert(link);
 516         assert(link->network);
 517         assert(link->manager);
 518
 519         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 520                 return;
 521
 522         switch (event) {
 523                 case SD_DHCP_CLIENT_EVENT_EXPIRED:
 524                 case SD_DHCP_CLIENT_EVENT_STOP:
 525                 case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
 526                         if (link->network->dhcp_critical) {
 527                                 log_link_error(link, "DHCPv4 connection considered system critical, ignoring request to reconfigure it.");
 528                                 return;
 529                         }
 530
 531                         if (link->dhcp_lease) {
 532                                 r = dhcp_lease_lost(link);
 533                                 if (r < 0) {
 534                                         link_enter_failed(link);
 535                                         return;
 536                                 }
 537                         }
 538
 539                         if (event == SD_DHCP_CLIENT_EVENT_IP_CHANGE) {
 540                                 r = dhcp_lease_acquired(client, link);
 541                                 if (r < 0) {
 542                                         link_enter_failed(link);
 543                                         return;
 544                                 }
 545                         }
 546
 547                         break;
 548                 case SD_DHCP_CLIENT_EVENT_RENEW:
 549                         r = dhcp_lease_renew(client, link);
 550                         if (r < 0) {
 551                                 link_enter_failed(link);
 552                                 return;
 553                         }
 554                         break;
 555                 case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
 556                         r = dhcp_lease_acquired(client, link);
 557                         if (r < 0) {
 558                                 link_enter_failed(link);
 559                                 return;
 560                         }
 561                         break;
 562                 default:
 563                         if (event < 0)
 564                                 log_link_warning_errno(link, event, "DHCP error: Client failed: %m");
 565                         else
 566                                 log_link_warning(link, "DHCP unknown event: %i", event);
 567                         break;
 568         }
 569
 570         return;
 571 }
 572
 573 static int dhcp4_set_hostname(Link *link) {
 574         _cleanup_free_ char *hostname = NULL;
 575         const char *hn;
 576         int r;
 577
 578         assert(link);
 579
 580         if (!link->network->dhcp_send_hostname)
 581                 hn = NULL;
 582         else if (link->network->dhcp_hostname)
 583                 hn = link->network->dhcp_hostname;
 584         else {
 585                 r = gethostname_strict(&hostname);
 586                 if (r < 0 && r != -ENXIO) /* ENXIO: no hostname set or hostname is "localhost" */
 587                         return r;
 588
 589                 hn = hostname;
 590         }
 591
 592         r = sd_dhcp_client_set_hostname(link->dhcp_client, hn);
 593         if (r == -EINVAL && hostname)
 594                 /* Ignore error when the machine's hostname is not suitable to send in DHCP packet. */
 595                 log_link_warning_errno(link, r, "DHCP4 CLIENT: Failed to set hostname from kernel hostname, ignoring: %m");
 596         else if (r < 0)
 597                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set hostname: %m");
 598
 599         return 0;
 600 }
 601
 602 static bool promote_secondaries_enabled(const char *ifname) {
 603         _cleanup_free_ char *promote_secondaries_sysctl = NULL;
 604         char *promote_secondaries_path;
 605         int r;
 606
 607         promote_secondaries_path = strjoina("net/ipv4/conf/", ifname, "/promote_secondaries");
 608         r = sysctl_read(promote_secondaries_path, &promote_secondaries_sysctl);
 609         if (r < 0) {
 610                 log_debug_errno(r, "Cannot read sysctl %s", promote_secondaries_path);
 611                 return false;
 612         }
 613
 614         truncate_nl(promote_secondaries_sysctl);
 615         r = parse_boolean(promote_secondaries_sysctl);
 616         if (r < 0)
 617                 log_warning_errno(r, "Cannot parse sysctl %s with content %s as boolean", promote_secondaries_path, promote_secondaries_sysctl);
 618         return r > 0;
 619 }
 620
 621 /* dhcp4_set_promote_secondaries will ensure this interface has
 622  * the "promote_secondaries" option in the kernel set. If this sysctl
 623  * is not set DHCP will work only as long as the IP address does not
 624  * changes between leases. The kernel will remove all secondary IP
 625  * addresses of an interface otherwise. The way systemd-network works
 626  * is that the new IP of a lease is added as a secondary IP and when
 627  * the primary one expires it relies on the kernel to promote the
 628  * secondary IP. See also https://github.com/systemd/systemd/issues/7163
 629  */
 630 int dhcp4_set_promote_secondaries(Link *link) {
 631         int r;
 632
 633         assert(link);
 634         assert(link->network);
 635         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 636
 637         /* check if the kernel has promote_secondaries enabled for our
 638          * interface. If it is not globally enabled or enabled for the
 639          * specific interface we must either enable it.
 640          */
 641         if (!(promote_secondaries_enabled("all") || promote_secondaries_enabled(link->ifname))) {
 642                 char *promote_secondaries_path = NULL;
 643
 644                 log_link_debug(link, "promote_secondaries is unset, setting it");
 645                 promote_secondaries_path = strjoina("net/ipv4/conf/", link->ifname, "/promote_secondaries");
 646                 r = sysctl_write(promote_secondaries_path, "1");
 647                 if (r < 0)
 648                         log_link_warning_errno(link, r, "cannot set sysctl %s to 1", promote_secondaries_path);
 649                 return r > 0;
 650         }
 651
 652         return 0;
 653 }
 654
 655 int dhcp4_set_client_identifier(Link *link) {
 656         int r;
 657
 658         assert(link);
 659         assert(link->network);
 660         assert(link->dhcp_client);
 661
 662         switch (link->network->dhcp_client_identifier) {
 663         case DHCP_CLIENT_ID_DUID: {
 664                 /* If configured, apply user specified DUID and IAID */
 665                 const DUID *duid = link_get_duid(link);
 666
 667                 if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
 668                         r = sd_dhcp_client_set_iaid_duid_llt(link->dhcp_client,
 669                                                              link->network->iaid_set,
 670                                                              link->network->iaid,
 671                                                              duid->llt_time);
 672                 else
 673                         r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
 674                                                          link->network->iaid_set,
 675                                                          link->network->iaid,
 676                                                          duid->type,
 677                                                          duid->raw_data_len > 0 ? duid->raw_data : NULL,
 678                                                          duid->raw_data_len);
 679                 if (r < 0)
 680                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set IAID+DUID: %m");
 681                 break;
 682         }
 683         case DHCP_CLIENT_ID_DUID_ONLY: {
 684                 /* If configured, apply user specified DUID */
 685                 const DUID *duid = link_get_duid(link);
 686
 687                 if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
 688                         r = sd_dhcp_client_set_duid_llt(link->dhcp_client,
 689                                                         duid->llt_time);
 690                 else
 691                         r = sd_dhcp_client_set_duid(link->dhcp_client,
 692                                                     duid->type,
 693                                                     duid->raw_data_len > 0 ? duid->raw_data : NULL,
 694                                                     duid->raw_data_len);
 695                 if (r < 0)
 696                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set DUID: %m");
 697                 break;
 698         }
 699         case DHCP_CLIENT_ID_MAC:
 700                 r = sd_dhcp_client_set_client_id(link->dhcp_client,
 701                                                  ARPHRD_ETHER,
 702                                                  (const uint8_t *) &link->mac,
 703                                                  sizeof(link->mac));
 704                 if (r < 0)
 705                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set client ID: %m");
 706                 break;
 707         default:
 708                 assert_not_reached("Unknown client identifier type.");
 709         }
 710
 711         return 0;
 712 }
 713
 714 int dhcp4_configure(Link *link) {
 715         int r;
 716
 717         assert(link);
 718         assert(link->network);
 719         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 720
 721         if (!link->dhcp_client) {
 722                 r = sd_dhcp_client_new(&link->dhcp_client, link->network->dhcp_anonymize);
 723                 if (r == -ENOMEM)
 724                         return log_oom();
 725                 if (r < 0)
 726                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to create DHCP4 client: %m");
 727         }
 728
 729         r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
 730         if (r < 0)
 731                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to attach event: %m");
 732
 733         r = sd_dhcp_client_set_mac(link->dhcp_client,
 734                                    (const uint8_t *) &link->mac,
 735                                    sizeof (link->mac), ARPHRD_ETHER);
 736         if (r < 0)
 737                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set MAC address: %m");
 738
 739         r = sd_dhcp_client_set_ifindex(link->dhcp_client, link->ifindex);
 740         if (r < 0)
 741                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set ifindex: %m");
 742
 743         r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp4_handler, link);
 744         if (r < 0)
 745                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set callback: %m");
 746
 747         r = sd_dhcp_client_set_request_broadcast(link->dhcp_client,
 748                                                  link->network->dhcp_broadcast);
 749         if (r < 0)
 750                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for broadcast: %m");
 751
 752         if (link->mtu) {
 753                 r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
 754                 if (r < 0)
 755                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set MTU: %m");
 756         }
 757
 758         if (link->network->dhcp_use_mtu) {
 759                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 760                                                       SD_DHCP_OPTION_INTERFACE_MTU);
 761                 if (r < 0)
 762                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for MTU: %m");
 763         }
 764
 765         /* NOTE: even if this variable is called "use", it also "sends" PRL
 766          * options, maybe there should be a different configuration variable
 767          * to send or not route options?. */
 768         /* NOTE: when using Anonymize=yes, routes PRL options are sent
 769          * by default, so they don't need to be added here. */
 770         if (link->network->dhcp_use_routes && !link->network->dhcp_anonymize) {
 771                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 772                                                       SD_DHCP_OPTION_STATIC_ROUTE);
 773                 if (r < 0)
 774                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for static route: %m");
 775
 776                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 777                                                       SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE);
 778                 if (r < 0)
 779                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for classless static route: %m");
 780         }
 781
 782         if (link->network->dhcp_use_ntp) {
 783                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NTP_SERVER);
 784                 if (r < 0)
 785                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for NTP server: %m");
 786         }
 787
 788         if (link->network->dhcp_use_timezone) {
 789                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NEW_TZDB_TIMEZONE);
 790                 if (r < 0)
 791                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for timezone: %m");
 792         }
 793
 794         r = dhcp4_set_hostname(link);
 795         if (r < 0)
 796                 return r;
 797
 798         if (link->network->dhcp_vendor_class_identifier) {
 799                 r = sd_dhcp_client_set_vendor_class_identifier(link->dhcp_client,
 800                                                                link->network->dhcp_vendor_class_identifier);
 801                 if (r < 0)
 802                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set vendor class identifier: %m");
 803         }
 804
 805         if (link->network->dhcp_user_class) {
 806                 r = sd_dhcp_client_set_user_class(link->dhcp_client, (const char **) link->network->dhcp_user_class);
 807                 if (r < 0)
 808                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set user class: %m");
 809         }
 810
 811         if (link->network->dhcp_client_port) {
 812                 r = sd_dhcp_client_set_client_port(link->dhcp_client, link->network->dhcp_client_port);
 813                 if (r < 0)
 814                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set listen port: %m");
 815         }
 816
 817         return dhcp4_set_client_identifier(link);
 818 }