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 "netdev/vrf.h"
  10 #include "network-internal.h"
  11 #include "networkd-link.h"
  12 #include "networkd-manager.h"
  13 #include "networkd-network.h"
  14 #include "string-util.h"
  15 #include "sysctl-util.h"
  16
  17 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
  18         int r;
  19
  20         assert(link);
  21         assert(link->dhcp4_messages > 0);
  22
  23         link->dhcp4_messages--;
  24
  25         r = sd_netlink_message_get_errno(m);
  26         if (r < 0 && r != -EEXIST) {
  27                 log_link_error_errno(link, r, "Could not set DHCPv4 route: %m");
  28                 link_enter_failed(link);
  29         }
  30
  31         if (link->dhcp4_messages == 0) {
  32                 link->dhcp4_configured = true;
  33                 link_check_ready(link);
  34         }
  35
  36         return 1;
  37 }
  38
  39 static int route_scope_from_address(const Route *route, const struct in_addr *self_addr) {
  40         assert(route);
  41         assert(self_addr);
  42
  43         if (in_addr_is_localhost(AF_INET, &route->dst) ||
  44             (self_addr->s_addr && route->dst.in.s_addr == self_addr->s_addr))
  45                 return RT_SCOPE_HOST;
  46         else if (in4_addr_is_null(&route->gw.in))
  47                 return RT_SCOPE_LINK;
  48         else
  49                 return RT_SCOPE_UNIVERSE;
  50 }
  51
  52 static int link_set_dhcp_routes(Link *link) {
  53         _cleanup_free_ sd_dhcp_route **static_routes = NULL;
  54         bool classless_route = false, static_route = false;
  55         struct in_addr gateway, 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         /* When the interface is part of an VRF use the VRFs routing table, unless
  71          * there is a another table specified. */
  72         table = link->network->dhcp_route_table;
  73         if (!link->network->dhcp_route_table_set && link->network->vrf != NULL)
  74                 table = VRF(link->network->vrf)->table;
  75
  76         r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
  77         if (r < 0)
  78                 return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
  79
  80         n = sd_dhcp_lease_get_routes(link->dhcp_lease, &static_routes);
  81         if (n == -ENODATA)
  82                 log_link_debug_errno(link, n, "DHCP: No routes received from DHCP server: %m");
  83         else if (n < 0)
  84                 log_link_debug_errno(link, n, "DHCP error: could not get routes: %m");
  85
  86         for (i = 0; i < n; i++) {
  87                 switch (sd_dhcp_route_get_option(static_routes[i])) {
  88                 case SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE:
  89                         classless_route = true;
  90                         break;
  91                 case SD_DHCP_OPTION_STATIC_ROUTE:
  92                         static_route = true;
  93                         break;
  94                 }
  95         }
  96
  97         for (i = 0; i < n; i++) {
  98                 _cleanup_(route_freep) Route *route = NULL;
  99
 100                 /* if the DHCP server returns both a Classless Static Routes option and a Static Routes option,
 101                    the DHCP client MUST ignore the Static Routes option. */
 102                 if (classless_route &&
 103                     sd_dhcp_route_get_option(static_routes[i]) != SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE)
 104                         continue;
 105
 106                 r = route_new(&route);
 107                 if (r < 0)
 108                         return log_link_error_errno(link, r, "Could not allocate route: %m");
 109
 110                 route->family = AF_INET;
 111                 route->protocol = RTPROT_DHCP;
 112                 assert_se(sd_dhcp_route_get_gateway(static_routes[i], &route->gw.in) >= 0);
 113                 assert_se(sd_dhcp_route_get_destination(static_routes[i], &route->dst.in) >= 0);
 114                 assert_se(sd_dhcp_route_get_destination_prefix_length(static_routes[i], &route->dst_prefixlen) >= 0);
 115                 route->priority = link->network->dhcp_route_metric;
 116                 route->table = table;
 117                 route->scope = route_scope_from_address(route, &address);
 118
 119                 r = route_configure(route, link, dhcp4_route_handler);
 120                 if (r < 0)
 121                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 122
 123                 link->dhcp4_messages++;
 124         }
 125
 126         r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
 127         if (r == -ENODATA)
 128                 log_link_info_errno(link, r, "DHCP: No gateway received from DHCP server: %m");
 129         else if (r < 0)
 130                 log_link_warning_errno(link, r, "DHCP error: could not get gateway: %m");
 131
 132         /* According to RFC 3442: If the DHCP server returns both a Classless Static Routes option and
 133            a Router option, the DHCP client MUST ignore the Router option. */
 134         if (classless_route && static_route)
 135                 log_link_warning(link, "Classless static routes received from DHCP server: ignoring static-route option and router option");
 136
 137         if (r >= 0 && !classless_route) {
 138                 _cleanup_(route_freep) Route *route = NULL;
 139                 _cleanup_(route_freep) Route *route_gw = NULL;
 140
 141                 r = route_new(&route);
 142                 if (r < 0)
 143                         return log_link_error_errno(link, r, "Could not allocate route: %m");
 144
 145                 route->protocol = RTPROT_DHCP;
 146
 147                 r = route_new(&route_gw);
 148                 if (r < 0)
 149                         return log_link_error_errno(link, r,  "Could not allocate route: %m");
 150
 151                 /* The dhcp netmask may mask out the gateway. Add an explicit
 152                  * route for the gw host so that we can route no matter the
 153                  * netmask or existing kernel route tables. */
 154                 route_gw->family = AF_INET;
 155                 route_gw->dst.in = gateway;
 156                 route_gw->dst_prefixlen = 32;
 157                 route_gw->prefsrc.in = address;
 158                 route_gw->scope = RT_SCOPE_LINK;
 159                 route_gw->protocol = RTPROT_DHCP;
 160                 route_gw->priority = link->network->dhcp_route_metric;
 161                 route_gw->table = table;
 162
 163                 r = route_configure(route_gw, link, dhcp4_route_handler);
 164                 if (r < 0)
 165                         return log_link_warning_errno(link, r, "Could not set host route: %m");
 166
 167                 link->dhcp4_messages++;
 168
 169                 route->family = AF_INET;
 170                 route->gw.in = gateway;
 171                 route->prefsrc.in = address;
 172                 route->priority = link->network->dhcp_route_metric;
 173                 route->table = table;
 174
 175                 r = route_configure(route, link, dhcp4_route_handler);
 176                 if (r < 0) {
 177                         log_link_warning_errno(link, r, "Could not set routes: %m");
 178                         link_enter_failed(link);
 179                         return r;
 180                 }
 181
 182                 link->dhcp4_messages++;
 183         }
 184
 185         return 0;
 186 }
 187
 188 static int dhcp_lease_lost(Link *link) {
 189         _cleanup_(address_freep) Address *address = NULL;
 190         struct in_addr addr;
 191         struct in_addr netmask;
 192         struct in_addr gateway;
 193         unsigned prefixlen = 0;
 194         int r;
 195
 196         assert(link);
 197         assert(link->dhcp_lease);
 198
 199         log_link_warning(link, "DHCP lease lost");
 200
 201         if (link->network->dhcp_use_routes) {
 202                 _cleanup_free_ sd_dhcp_route **routes = NULL;
 203                 int n, i;
 204
 205                 n = sd_dhcp_lease_get_routes(link->dhcp_lease, &routes);
 206                 if (n >= 0) {
 207                         for (i = 0; i < n; i++) {
 208                                 _cleanup_(route_freep) Route *route = NULL;
 209
 210                                 r = route_new(&route);
 211                                 if (r >= 0) {
 212                                         route->family = AF_INET;
 213                                         assert_se(sd_dhcp_route_get_gateway(routes[i], &route->gw.in) >= 0);
 214                                         assert_se(sd_dhcp_route_get_destination(routes[i], &route->dst.in) >= 0);
 215                                         assert_se(sd_dhcp_route_get_destination_prefix_length(routes[i], &route->dst_prefixlen) >= 0);
 216
 217                                         route_remove(route, link, NULL);
 218                                 }
 219                         }
 220                 }
 221         }
 222
 223         r = address_new(&address);
 224         if (r >= 0) {
 225                 r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
 226                 if (r >= 0) {
 227                         _cleanup_(route_freep) Route *route_gw = NULL;
 228                         _cleanup_(route_freep) Route *route = NULL;
 229
 230                         r = route_new(&route_gw);
 231                         if (r >= 0) {
 232                                 route_gw->family = AF_INET;
 233                                 route_gw->dst.in = gateway;
 234                                 route_gw->dst_prefixlen = 32;
 235                                 route_gw->scope = RT_SCOPE_LINK;
 236
 237                                 route_remove(route_gw, link, NULL);
 238                         }
 239
 240                         r = route_new(&route);
 241                         if (r >= 0) {
 242                                 route->family = AF_INET;
 243                                 route->gw.in = gateway;
 244
 245                                 route_remove(route, link, NULL);
 246                         }
 247                 }
 248
 249                 r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr);
 250                 if (r >= 0) {
 251                         r = sd_dhcp_lease_get_netmask(link->dhcp_lease, &netmask);
 252                         if (r >= 0)
 253                                 prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 254
 255                         address->family = AF_INET;
 256                         address->in_addr.in = addr;
 257                         address->prefixlen = prefixlen;
 258
 259                         address_remove(address, link, NULL);
 260                 }
 261         }
 262
 263         if (link->network->dhcp_use_mtu) {
 264                 uint16_t mtu;
 265
 266                 r = sd_dhcp_lease_get_mtu(link->dhcp_lease, &mtu);
 267                 if (r >= 0 && link->original_mtu != mtu) {
 268                         r = link_set_mtu(link, link->original_mtu);
 269                         if (r < 0) {
 270                                 log_link_warning(link,
 271                                                  "DHCP error: could not reset MTU");
 272                                 link_enter_failed(link);
 273                                 return r;
 274                         }
 275                 }
 276         }
 277
 278         if (link->network->dhcp_use_hostname) {
 279                 const char *hostname = NULL;
 280
 281                 if (link->network->dhcp_hostname)
 282                         hostname = link->network->dhcp_hostname;
 283                 else
 284                         (void) sd_dhcp_lease_get_hostname(link->dhcp_lease, &hostname);
 285
 286                 if (hostname) {
 287                         /* If a hostname was set due to the lease, then unset it now. */
 288                         r = manager_set_hostname(link->manager, NULL);
 289                         if (r < 0)
 290                                 log_link_warning_errno(link, r, "Failed to reset transient hostname: %m");
 291                 }
 292         }
 293
 294         link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
 295         link_dirty(link);
 296         link->dhcp4_configured = false;
 297
 298         return 0;
 299 }
 300
 301 static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
 302         int r;
 303
 304         assert(link);
 305
 306         r = sd_netlink_message_get_errno(m);
 307         if (r < 0 && r != -EEXIST) {
 308                 log_link_error_errno(link, r, "Could not set DHCPv4 address: %m");
 309                 link_enter_failed(link);
 310         } else if (r >= 0)
 311                 manager_rtnl_process_address(rtnl, m, link->manager);
 312
 313         link_set_dhcp_routes(link);
 314
 315         if (link->dhcp4_messages == 0) {
 316                 link->dhcp4_configured = true;
 317                 link_check_ready(link);
 318         }
 319
 320         return 1;
 321 }
 322
 323 static int dhcp4_update_address(Link *link,
 324                                 struct in_addr *address,
 325                                 struct in_addr *netmask,
 326                                 uint32_t lifetime) {
 327         _cleanup_(address_freep) Address *addr = NULL;
 328         unsigned prefixlen;
 329         int r;
 330
 331         assert(address);
 332         assert(netmask);
 333         assert(lifetime);
 334
 335         prefixlen = in4_addr_netmask_to_prefixlen(netmask);
 336
 337         r = address_new(&addr);
 338         if (r < 0)
 339                 return r;
 340
 341         addr->family = AF_INET;
 342         addr->in_addr.in.s_addr = address->s_addr;
 343         addr->cinfo.ifa_prefered = lifetime;
 344         addr->cinfo.ifa_valid = lifetime;
 345         addr->prefixlen = prefixlen;
 346         addr->broadcast.s_addr = address->s_addr | ~netmask->s_addr;
 347
 348         /* allow reusing an existing address and simply update its lifetime
 349          * in case it already exists */
 350         r = address_configure(addr, link, dhcp4_address_handler, true);
 351         if (r < 0)
 352                 return r;
 353
 354         return 0;
 355 }
 356
 357 static int dhcp_lease_renew(sd_dhcp_client *client, Link *link) {
 358         sd_dhcp_lease *lease;
 359         struct in_addr address;
 360         struct in_addr netmask;
 361         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 362         int r;
 363
 364         assert(link);
 365         assert(client);
 366         assert(link->network);
 367
 368         r = sd_dhcp_client_get_lease(client, &lease);
 369         if (r < 0)
 370                 return log_link_warning_errno(link, r, "DHCP error: no lease: %m");
 371
 372         sd_dhcp_lease_unref(link->dhcp_lease);
 373         link->dhcp4_configured = false;
 374         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 375         link_dirty(link);
 376
 377         r = sd_dhcp_lease_get_address(lease, &address);
 378         if (r < 0)
 379                 return log_link_warning_errno(link, r, "DHCP error: no address: %m");
 380
 381         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 382         if (r < 0)
 383                 return log_link_warning_errno(link, r, "DHCP error: no netmask: %m");
 384
 385         if (!link->network->dhcp_critical) {
 386                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 387                 if (r < 0)
 388                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 389         }
 390
 391         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 392         if (r < 0) {
 393                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 394                 link_enter_failed(link);
 395                 return r;
 396         }
 397
 398         return 0;
 399 }
 400
 401 static int dhcp_lease_acquired(sd_dhcp_client *client, Link *link) {
 402         sd_dhcp_lease *lease;
 403         struct in_addr address;
 404         struct in_addr netmask;
 405         struct in_addr gateway;
 406         unsigned prefixlen;
 407         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 408         int r;
 409
 410         assert(client);
 411         assert(link);
 412
 413         r = sd_dhcp_client_get_lease(client, &lease);
 414         if (r < 0)
 415                 return log_link_error_errno(link, r, "DHCP error: No lease: %m");
 416
 417         r = sd_dhcp_lease_get_address(lease, &address);
 418         if (r < 0)
 419                 return log_link_error_errno(link, r, "DHCP error: No address: %m");
 420
 421         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 422         if (r < 0)
 423                 return log_link_error_errno(link, r, "DHCP error: No netmask: %m");
 424
 425         prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 426
 427         r = sd_dhcp_lease_get_router(lease, &gateway);
 428         if (r < 0 && r != -ENODATA)
 429                 return log_link_error_errno(link, r, "DHCP error: Could not get gateway: %m");
 430
 431         if (r >= 0)
 432                 log_struct(LOG_INFO,
 433                            LOG_LINK_INTERFACE(link),
 434                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
 435                                             ADDRESS_FMT_VAL(address),
 436                                             prefixlen,
 437                                             ADDRESS_FMT_VAL(gateway)),
 438                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 439                            "PREFIXLEN=%u", prefixlen,
 440                            "GATEWAY=%u.%u.%u.%u", ADDRESS_FMT_VAL(gateway));
 441         else
 442                 log_struct(LOG_INFO,
 443                            LOG_LINK_INTERFACE(link),
 444                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u",
 445                                             ADDRESS_FMT_VAL(address),
 446                                             prefixlen),
 447                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 448                            "PREFIXLEN=%u", prefixlen);
 449
 450         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 451         link_dirty(link);
 452
 453         if (link->network->dhcp_use_mtu) {
 454                 uint16_t mtu;
 455
 456                 r = sd_dhcp_lease_get_mtu(lease, &mtu);
 457                 if (r >= 0) {
 458                         r = link_set_mtu(link, mtu);
 459                         if (r < 0)
 460                                 log_link_error_errno(link, r, "Failed to set MTU to %" PRIu16 ": %m", mtu);
 461                 }
 462         }
 463
 464         if (link->network->dhcp_use_hostname) {
 465                 const char *dhcpname = NULL;
 466                 _cleanup_free_ char *hostname = NULL;
 467
 468                 if (link->network->dhcp_hostname)
 469                         dhcpname = link->network->dhcp_hostname;
 470                 else
 471                         (void) sd_dhcp_lease_get_hostname(lease, &dhcpname);
 472
 473                 if (dhcpname) {
 474                         r = shorten_overlong(dhcpname, &hostname);
 475                         if (r < 0)
 476                                 log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s', ignoring: %m", dhcpname);
 477                         if (r == 1)
 478                                 log_link_notice(link, "Overlong DCHP hostname received, shortened from '%s' to '%s'", dhcpname, hostname);
 479                 }
 480
 481                 if (hostname) {
 482                         r = manager_set_hostname(link->manager, hostname);
 483                         if (r < 0)
 484                                 log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
 485                 }
 486         }
 487
 488         if (link->network->dhcp_use_timezone) {
 489                 const char *tz = NULL;
 490
 491                 (void) sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
 492
 493                 if (tz) {
 494                         r = manager_set_timezone(link->manager, tz);
 495                         if (r < 0)
 496                                 log_link_error_errno(link, r, "Failed to set timezone to '%s': %m", tz);
 497                 }
 498         }
 499
 500         if (!link->network->dhcp_critical) {
 501                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 502                 if (r < 0)
 503                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 504         }
 505
 506         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 507         if (r < 0) {
 508                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 509                 link_enter_failed(link);
 510                 return r;
 511         }
 512
 513         return 0;
 514 }
 515 static void dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
 516         Link *link = userdata;
 517         int r = 0;
 518
 519         assert(link);
 520         assert(link->network);
 521         assert(link->manager);
 522
 523         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 524                 return;
 525
 526         switch (event) {
 527                 case SD_DHCP_CLIENT_EVENT_EXPIRED:
 528                 case SD_DHCP_CLIENT_EVENT_STOP:
 529                 case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
 530                         if (link->network->dhcp_critical) {
 531                                 log_link_error(link, "DHCPv4 connection considered system critical, ignoring request to reconfigure it.");
 532                                 return;
 533                         }
 534
 535                         if (link->dhcp_lease) {
 536                                 r = dhcp_lease_lost(link);
 537                                 if (r < 0) {
 538                                         link_enter_failed(link);
 539                                         return;
 540                                 }
 541                         }
 542
 543                         if (event == SD_DHCP_CLIENT_EVENT_IP_CHANGE) {
 544                                 r = dhcp_lease_acquired(client, link);
 545                                 if (r < 0) {
 546                                         link_enter_failed(link);
 547                                         return;
 548                                 }
 549                         }
 550
 551                         break;
 552                 case SD_DHCP_CLIENT_EVENT_RENEW:
 553                         r = dhcp_lease_renew(client, link);
 554                         if (r < 0) {
 555                                 link_enter_failed(link);
 556                                 return;
 557                         }
 558                         break;
 559                 case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
 560                         r = dhcp_lease_acquired(client, link);
 561                         if (r < 0) {
 562                                 link_enter_failed(link);
 563                                 return;
 564                         }
 565                         break;
 566                 default:
 567                         if (event < 0)
 568                                 log_link_warning_errno(link, event, "DHCP error: Client failed: %m");
 569                         else
 570                                 log_link_warning(link, "DHCP unknown event: %i", event);
 571                         break;
 572         }
 573
 574         return;
 575 }
 576
 577 static int dhcp4_set_hostname(Link *link) {
 578         _cleanup_free_ char *hostname = NULL;
 579         const char *hn;
 580         int r;
 581
 582         assert(link);
 583
 584         if (!link->network->dhcp_send_hostname)
 585                 hn = NULL;
 586         else if (link->network->dhcp_hostname)
 587                 hn = link->network->dhcp_hostname;
 588         else {
 589                 r = gethostname_strict(&hostname);
 590                 if (r < 0 && r != -ENXIO) /* ENXIO: no hostname set or hostname is "localhost" */
 591                         return r;
 592
 593                 hn = hostname;
 594         }
 595
 596         r = sd_dhcp_client_set_hostname(link->dhcp_client, hn);
 597         if (r == -EINVAL && hostname)
 598                 /* Ignore error when the machine's hostname is not suitable to send in DHCP packet. */
 599                 log_link_warning_errno(link, r, "DHCP4 CLIENT: Failed to set hostname from kernel hostname, ignoring: %m");
 600         else if (r < 0)
 601                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set hostname: %m");
 602
 603         return 0;
 604 }
 605
 606 static bool promote_secondaries_enabled(const char *ifname) {
 607         _cleanup_free_ char *promote_secondaries_sysctl = NULL;
 608         char *promote_secondaries_path;
 609         int r;
 610
 611         promote_secondaries_path = strjoina("net/ipv4/conf/", ifname, "/promote_secondaries");
 612         r = sysctl_read(promote_secondaries_path, &promote_secondaries_sysctl);
 613         if (r < 0) {
 614                 log_debug_errno(r, "Cannot read sysctl %s", promote_secondaries_path);
 615                 return false;
 616         }
 617
 618         truncate_nl(promote_secondaries_sysctl);
 619         r = parse_boolean(promote_secondaries_sysctl);
 620         if (r < 0)
 621                 log_warning_errno(r, "Cannot parse sysctl %s with content %s as boolean", promote_secondaries_path, promote_secondaries_sysctl);
 622         return r > 0;
 623 }
 624
 625 /* dhcp4_set_promote_secondaries will ensure this interface has
 626  * the "promote_secondaries" option in the kernel set. If this sysctl
 627  * is not set DHCP will work only as long as the IP address does not
 628  * changes between leases. The kernel will remove all secondary IP
 629  * addresses of an interface otherwise. The way systemd-network works
 630  * is that the new IP of a lease is added as a secondary IP and when
 631  * the primary one expires it relies on the kernel to promote the
 632  * secondary IP. See also https://github.com/systemd/systemd/issues/7163
 633  */
 634 int dhcp4_set_promote_secondaries(Link *link) {
 635         int r;
 636
 637         assert(link);
 638         assert(link->network);
 639         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 640
 641         /* check if the kernel has promote_secondaries enabled for our
 642          * interface. If it is not globally enabled or enabled for the
 643          * specific interface we must either enable it.
 644          */
 645         if (!(promote_secondaries_enabled("all") || promote_secondaries_enabled(link->ifname))) {
 646                 char *promote_secondaries_path = NULL;
 647
 648                 log_link_debug(link, "promote_secondaries is unset, setting it");
 649                 promote_secondaries_path = strjoina("net/ipv4/conf/", link->ifname, "/promote_secondaries");
 650                 r = sysctl_write(promote_secondaries_path, "1");
 651                 if (r < 0)
 652                         log_link_warning_errno(link, r, "cannot set sysctl %s to 1", promote_secondaries_path);
 653                 return r > 0;
 654         }
 655
 656         return 0;
 657 }
 658
 659 int dhcp4_set_client_identifier(Link *link) {
 660         int r;
 661
 662         assert(link);
 663         assert(link->network);
 664         assert(link->dhcp_client);
 665
 666         switch (link->network->dhcp_client_identifier) {
 667         case DHCP_CLIENT_ID_DUID: {
 668                 /* If configured, apply user specified DUID and IAID */
 669                 const DUID *duid = link_get_duid(link);
 670
 671                 if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
 672                         r = sd_dhcp_client_set_iaid_duid_llt(link->dhcp_client,
 673                                                              link->network->iaid_set,
 674                                                              link->network->iaid,
 675                                                              duid->llt_time);
 676                 else
 677                         r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
 678                                                          link->network->iaid_set,
 679                                                          link->network->iaid,
 680                                                          duid->type,
 681                                                          duid->raw_data_len > 0 ? duid->raw_data : NULL,
 682                                                          duid->raw_data_len);
 683                 if (r < 0)
 684                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set IAID+DUID: %m");
 685                 break;
 686         }
 687         case DHCP_CLIENT_ID_DUID_ONLY: {
 688                 /* If configured, apply user specified DUID */
 689                 const DUID *duid = link_get_duid(link);
 690
 691                 if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
 692                         r = sd_dhcp_client_set_duid_llt(link->dhcp_client,
 693                                                         duid->llt_time);
 694                 else
 695                         r = sd_dhcp_client_set_duid(link->dhcp_client,
 696                                                     duid->type,
 697                                                     duid->raw_data_len > 0 ? duid->raw_data : NULL,
 698                                                     duid->raw_data_len);
 699                 if (r < 0)
 700                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set DUID: %m");
 701                 break;
 702         }
 703         case DHCP_CLIENT_ID_MAC:
 704                 r = sd_dhcp_client_set_client_id(link->dhcp_client,
 705                                                  ARPHRD_ETHER,
 706                                                  (const uint8_t *) &link->mac,
 707                                                  sizeof(link->mac));
 708                 if (r < 0)
 709                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set client ID: %m");
 710                 break;
 711         default:
 712                 assert_not_reached("Unknown client identifier type.");
 713         }
 714
 715         return 0;
 716 }
 717
 718 int dhcp4_configure(Link *link) {
 719         int r;
 720
 721         assert(link);
 722         assert(link->network);
 723         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 724
 725         if (!link->dhcp_client) {
 726                 r = sd_dhcp_client_new(&link->dhcp_client, link->network->dhcp_anonymize);
 727                 if (r == -ENOMEM)
 728                         return log_oom();
 729                 if (r < 0)
 730                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to create DHCP4 client: %m");
 731         }
 732
 733         r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
 734         if (r < 0)
 735                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to attach event: %m");
 736
 737         r = sd_dhcp_client_set_mac(link->dhcp_client,
 738                                    (const uint8_t *) &link->mac,
 739                                    sizeof (link->mac), ARPHRD_ETHER);
 740         if (r < 0)
 741                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set MAC address: %m");
 742
 743         r = sd_dhcp_client_set_ifindex(link->dhcp_client, link->ifindex);
 744         if (r < 0)
 745                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set ifindex: %m");
 746
 747         r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp4_handler, link);
 748         if (r < 0)
 749                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set callback: %m");
 750
 751         r = sd_dhcp_client_set_request_broadcast(link->dhcp_client,
 752                                                  link->network->dhcp_broadcast);
 753         if (r < 0)
 754                 return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for broadcast: %m");
 755
 756         if (link->mtu) {
 757                 r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
 758                 if (r < 0)
 759                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set MTU: %m");
 760         }
 761
 762         if (link->network->dhcp_use_mtu) {
 763                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 764                                                       SD_DHCP_OPTION_INTERFACE_MTU);
 765                 if (r < 0)
 766                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for MTU: %m");
 767         }
 768
 769         /* NOTE: even if this variable is called "use", it also "sends" PRL
 770          * options, maybe there should be a different configuration variable
 771          * to send or not route options?. */
 772         /* NOTE: when using Anonymize=yes, routes PRL options are sent
 773          * by default, so they don't need to be added here. */
 774         if (link->network->dhcp_use_routes && !link->network->dhcp_anonymize) {
 775                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 776                                                       SD_DHCP_OPTION_STATIC_ROUTE);
 777                 if (r < 0)
 778                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for static route: %m");
 779
 780                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 781                                                       SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE);
 782                 if (r < 0)
 783                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for classless static route: %m");
 784         }
 785
 786         if (link->network->dhcp_use_ntp) {
 787                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NTP_SERVER);
 788                 if (r < 0)
 789                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for NTP server: %m");
 790         }
 791
 792         if (link->network->dhcp_use_timezone) {
 793                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NEW_TZDB_TIMEZONE);
 794                 if (r < 0)
 795                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set request flag for timezone: %m");
 796         }
 797
 798         r = dhcp4_set_hostname(link);
 799         if (r < 0)
 800                 return r;
 801
 802         if (link->network->dhcp_vendor_class_identifier) {
 803                 r = sd_dhcp_client_set_vendor_class_identifier(link->dhcp_client,
 804                                                                link->network->dhcp_vendor_class_identifier);
 805                 if (r < 0)
 806                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set vendor class identifier: %m");
 807         }
 808
 809         if (link->network->dhcp_user_class) {
 810                 r = sd_dhcp_client_set_user_class(link->dhcp_client, (const char **) link->network->dhcp_user_class);
 811                 if (r < 0)
 812                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set user class: %m");
 813         }
 814
 815         if (link->network->dhcp_client_port) {
 816                 r = sd_dhcp_client_set_client_port(link->dhcp_client, link->network->dhcp_client_port);
 817                 if (r < 0)
 818                         return log_link_error_errno(link, r, "DHCP4 CLIENT: Failed to set listen port: %m");
 819         }
 820
 821         return dhcp4_set_client_identifier(link);
 822 }