src/network/networkd-dhcp4.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright © 2013-2014 Tom Gundersen <teg@jklm.no>
   4 ***/
   5
   6 #include <netinet/ether.h>
   7 #include <linux/if.h>
   8
   9 #include "alloc-util.h"
  10 #include "dhcp-lease-internal.h"
  11 #include "hostname-util.h"
  12 #include "parse-util.h"
  13 #include "netdev/vrf.h"
  14 #include "network-internal.h"
  15 #include "networkd-link.h"
  16 #include "networkd-manager.h"
  17 #include "networkd-network.h"
  18 #include "string-util.h"
  19 #include "sysctl-util.h"
  20
  21 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m,
  22                                void *userdata) {
  23         _cleanup_(link_unrefp) Link *link = userdata;
  24         int r;
  25
  26         assert(link);
  27         assert(link->dhcp4_messages > 0);
  28
  29         link->dhcp4_messages--;
  30
  31         r = sd_netlink_message_get_errno(m);
  32         if (r < 0 && r != -EEXIST) {
  33                 log_link_error_errno(link, r, "Could not set DHCPv4 route: %m");
  34                 link_enter_failed(link);
  35         }
  36
  37         if (link->dhcp4_messages == 0) {
  38                 link->dhcp4_configured = true;
  39                 link_check_ready(link);
  40         }
  41
  42         return 1;
  43 }
  44
  45 static int route_scope_from_address(const Route *route, const struct in_addr *self_addr) {
  46         assert(route);
  47         assert(self_addr);
  48
  49         if (in_addr_is_localhost(AF_INET, &route->dst) ||
  50             (self_addr->s_addr && route->dst.in.s_addr == self_addr->s_addr))
  51                 return RT_SCOPE_HOST;
  52         else if (in4_addr_is_null(&route->gw.in))
  53                 return RT_SCOPE_LINK;
  54         else
  55                 return RT_SCOPE_UNIVERSE;
  56 }
  57
  58 static int link_set_dhcp_routes(Link *link) {
  59         _cleanup_free_ sd_dhcp_route **static_routes = NULL;
  60         bool classless_route = false, static_route = false;
  61         struct in_addr gateway, address;
  62         int r, n, i;
  63         uint32_t table;
  64
  65         assert(link);
  66
  67         if (!link->dhcp_lease) /* link went down while we configured the IP addresses? */
  68                 return 0;
  69
  70         if (!link->network) /* link went down while we configured the IP addresses? */
  71                 return 0;
  72
  73         if (!link->network->dhcp_use_routes)
  74                 return 0;
  75
  76         /* When the interface is part of an VRF use the VRFs routing table, unless
  77          * there is a another table specified. */
  78         table = link->network->dhcp_route_table;
  79         if (!link->network->dhcp_route_table_set && link->network->vrf != NULL)
  80                 table = VRF(link->network->vrf)->table;
  81
  82         r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
  83         if (r < 0)
  84                 return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
  85
  86         n = sd_dhcp_lease_get_routes(link->dhcp_lease, &static_routes);
  87         if (n < 0)
  88                 log_link_debug_errno(link, n, "DHCP error: could not get routes: %m");
  89
  90         for (i = 0; i < n; i++) {
  91                 if (static_routes[i]->option == SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE)
  92                         classless_route = true;
  93
  94                 if (static_routes[i]->option == SD_DHCP_OPTION_STATIC_ROUTE)
  95                         static_route = true;
  96         }
  97
  98         for (i = 0; i < n; i++) {
  99                 _cleanup_(route_freep) Route *route = NULL;
 100
 101                 /* if the DHCP server returns both a Classless Static Routes option and a Static Routes option,
 102                    the DHCP client MUST ignore the Static Routes option. */
 103                 if (classless_route && static_routes[i]->option == SD_DHCP_OPTION_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 routes 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,
 218                                                      link_route_remove_handler);
 219                                 }
 220                         }
 221                 }
 222         }
 223
 224         r = address_new(&address);
 225         if (r >= 0) {
 226                 r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
 227                 if (r >= 0) {
 228                         _cleanup_(route_freep) Route *route_gw = NULL;
 229                         _cleanup_(route_freep) Route *route = NULL;
 230
 231                         r = route_new(&route_gw);
 232                         if (r >= 0) {
 233                                 route_gw->family = AF_INET;
 234                                 route_gw->dst.in = gateway;
 235                                 route_gw->dst_prefixlen = 32;
 236                                 route_gw->scope = RT_SCOPE_LINK;
 237
 238                                 route_remove(route_gw, link,
 239                                              link_route_remove_handler);
 240                         }
 241
 242                         r = route_new(&route);
 243                         if (r >= 0) {
 244                                 route->family = AF_INET;
 245                                 route->gw.in = gateway;
 246
 247                                 route_remove(route, link,
 248                                              link_route_remove_handler);
 249                         }
 250                 }
 251
 252                 r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr);
 253                 if (r >= 0) {
 254                         r = sd_dhcp_lease_get_netmask(link->dhcp_lease, &netmask);
 255                         if (r >= 0)
 256                                 prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 257
 258                         address->family = AF_INET;
 259                         address->in_addr.in = addr;
 260                         address->prefixlen = prefixlen;
 261
 262                         address_remove(address, link, link_address_remove_handler);
 263                 }
 264         }
 265
 266         if (link->network->dhcp_use_mtu) {
 267                 uint16_t mtu;
 268
 269                 r = sd_dhcp_lease_get_mtu(link->dhcp_lease, &mtu);
 270                 if (r >= 0 && link->original_mtu != mtu) {
 271                         r = link_set_mtu(link, link->original_mtu);
 272                         if (r < 0) {
 273                                 log_link_warning(link,
 274                                                  "DHCP error: could not reset MTU");
 275                                 link_enter_failed(link);
 276                                 return r;
 277                         }
 278                 }
 279         }
 280
 281         if (link->network->dhcp_use_hostname) {
 282                 const char *hostname = NULL;
 283
 284                 if (link->network->dhcp_hostname)
 285                         hostname = link->network->dhcp_hostname;
 286                 else
 287                         (void) sd_dhcp_lease_get_hostname(link->dhcp_lease, &hostname);
 288
 289                 if (hostname) {
 290                         /* If a hostname was set due to the lease, then unset it now. */
 291                         r = manager_set_hostname(link->manager, NULL);
 292                         if (r < 0)
 293                                 log_link_warning_errno(link, r, "Failed to reset transient hostname: %m");
 294                 }
 295         }
 296
 297         link->dhcp_lease = sd_dhcp_lease_unref(link->dhcp_lease);
 298         link_dirty(link);
 299         link->dhcp4_configured = false;
 300
 301         return 0;
 302 }
 303
 304 static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m,
 305                                  void *userdata) {
 306         _cleanup_(link_unrefp) Link *link = userdata;
 307         int r;
 308
 309         assert(link);
 310
 311         r = sd_netlink_message_get_errno(m);
 312         if (r < 0 && r != -EEXIST) {
 313                 log_link_error_errno(link, r, "Could not set DHCPv4 address: %m");
 314                 link_enter_failed(link);
 315         } else if (r >= 0)
 316                 manager_rtnl_process_address(rtnl, m, link->manager);
 317
 318         link_set_dhcp_routes(link);
 319
 320         if (link->dhcp4_messages == 0) {
 321                 link->dhcp4_configured = true;
 322                 link_check_ready(link);
 323         }
 324
 325         return 1;
 326 }
 327
 328 static int dhcp4_update_address(Link *link,
 329                                 struct in_addr *address,
 330                                 struct in_addr *netmask,
 331                                 uint32_t lifetime) {
 332         _cleanup_(address_freep) Address *addr = NULL;
 333         unsigned prefixlen;
 334         int r;
 335
 336         assert(address);
 337         assert(netmask);
 338         assert(lifetime);
 339
 340         prefixlen = in4_addr_netmask_to_prefixlen(netmask);
 341
 342         r = address_new(&addr);
 343         if (r < 0)
 344                 return r;
 345
 346         addr->family = AF_INET;
 347         addr->in_addr.in.s_addr = address->s_addr;
 348         addr->cinfo.ifa_prefered = lifetime;
 349         addr->cinfo.ifa_valid = lifetime;
 350         addr->prefixlen = prefixlen;
 351         addr->broadcast.s_addr = address->s_addr | ~netmask->s_addr;
 352
 353         /* allow reusing an existing address and simply update its lifetime
 354          * in case it already exists */
 355         r = address_configure(addr, link, dhcp4_address_handler, true);
 356         if (r < 0)
 357                 return r;
 358
 359         return 0;
 360 }
 361
 362 static int dhcp_lease_renew(sd_dhcp_client *client, Link *link) {
 363         sd_dhcp_lease *lease;
 364         struct in_addr address;
 365         struct in_addr netmask;
 366         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 367         int r;
 368
 369         assert(link);
 370         assert(client);
 371         assert(link->network);
 372
 373         r = sd_dhcp_client_get_lease(client, &lease);
 374         if (r < 0)
 375                 return log_link_warning_errno(link, r, "DHCP error: no lease: %m");
 376
 377         sd_dhcp_lease_unref(link->dhcp_lease);
 378         link->dhcp4_configured = false;
 379         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 380         link_dirty(link);
 381
 382         r = sd_dhcp_lease_get_address(lease, &address);
 383         if (r < 0)
 384                 return log_link_warning_errno(link, r, "DHCP error: no address: %m");
 385
 386         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 387         if (r < 0)
 388                 return log_link_warning_errno(link, r, "DHCP error: no netmask: %m");
 389
 390         if (!link->network->dhcp_critical) {
 391                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 392                 if (r < 0)
 393                         return log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 394         }
 395
 396         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 397         if (r < 0) {
 398                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 399                 link_enter_failed(link);
 400                 return r;
 401         }
 402
 403         return 0;
 404 }
 405
 406 static int dhcp_lease_acquired(sd_dhcp_client *client, Link *link) {
 407         sd_dhcp_lease *lease;
 408         struct in_addr address;
 409         struct in_addr netmask;
 410         struct in_addr gateway;
 411         unsigned prefixlen;
 412         uint32_t lifetime = CACHE_INFO_INFINITY_LIFE_TIME;
 413         int r;
 414
 415         assert(client);
 416         assert(link);
 417
 418         r = sd_dhcp_client_get_lease(client, &lease);
 419         if (r < 0)
 420                 return log_link_error_errno(link, r, "DHCP error: No lease: %m");
 421
 422         r = sd_dhcp_lease_get_address(lease, &address);
 423         if (r < 0)
 424                 return log_link_error_errno(link, r, "DHCP error: No address: %m");
 425
 426         r = sd_dhcp_lease_get_netmask(lease, &netmask);
 427         if (r < 0)
 428                 return log_link_error_errno(link, r, "DHCP error: No netmask: %m");
 429
 430         prefixlen = in4_addr_netmask_to_prefixlen(&netmask);
 431
 432         r = sd_dhcp_lease_get_router(lease, &gateway);
 433         if (r < 0 && r != -ENODATA)
 434                 return log_link_error_errno(link, r, "DHCP error: Could not get gateway: %m");
 435
 436         if (r >= 0)
 437                 log_struct(LOG_INFO,
 438                            LOG_LINK_INTERFACE(link),
 439                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
 440                                             ADDRESS_FMT_VAL(address),
 441                                             prefixlen,
 442                                             ADDRESS_FMT_VAL(gateway)),
 443                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 444                            "PREFIXLEN=%u", prefixlen,
 445                            "GATEWAY=%u.%u.%u.%u", ADDRESS_FMT_VAL(gateway));
 446         else
 447                 log_struct(LOG_INFO,
 448                            LOG_LINK_INTERFACE(link),
 449                            LOG_LINK_MESSAGE(link, "DHCPv4 address %u.%u.%u.%u/%u",
 450                                             ADDRESS_FMT_VAL(address),
 451                                             prefixlen),
 452                            "ADDRESS=%u.%u.%u.%u", ADDRESS_FMT_VAL(address),
 453                            "PREFIXLEN=%u", prefixlen);
 454
 455         link->dhcp_lease = sd_dhcp_lease_ref(lease);
 456         link_dirty(link);
 457
 458         if (link->network->dhcp_use_mtu) {
 459                 uint16_t mtu;
 460
 461                 r = sd_dhcp_lease_get_mtu(lease, &mtu);
 462                 if (r >= 0) {
 463                         r = link_set_mtu(link, mtu);
 464                         if (r < 0)
 465                                 log_link_error_errno(link, r, "Failed to set MTU to %" PRIu16 ": %m", mtu);
 466                 }
 467         }
 468
 469         if (link->network->dhcp_use_hostname) {
 470                 const char *dhcpname = NULL;
 471                 _cleanup_free_ char *hostname = NULL;
 472
 473                 if (link->network->dhcp_hostname)
 474                         dhcpname = link->network->dhcp_hostname;
 475                 else
 476                         (void) sd_dhcp_lease_get_hostname(lease, &dhcpname);
 477
 478                 if (dhcpname) {
 479                         r = shorten_overlong(dhcpname, &hostname);
 480                         if (r < 0)
 481                                 log_link_warning_errno(link, r, "Unable to shorten overlong DHCP hostname '%s', ignoring: %m", dhcpname);
 482                         if (r == 1)
 483                                 log_link_notice(link, "Overlong DCHP hostname received, shortened from '%s' to '%s'", dhcpname, hostname);
 484                 }
 485
 486                 if (hostname) {
 487                         r = manager_set_hostname(link->manager, hostname);
 488                         if (r < 0)
 489                                 log_link_error_errno(link, r, "Failed to set transient hostname to '%s': %m", hostname);
 490                 }
 491         }
 492
 493         if (link->network->dhcp_use_timezone) {
 494                 const char *tz = NULL;
 495
 496                 (void) sd_dhcp_lease_get_timezone(link->dhcp_lease, &tz);
 497
 498                 if (tz) {
 499                         r = manager_set_timezone(link->manager, tz);
 500                         if (r < 0)
 501                                 log_link_error_errno(link, r, "Failed to set timezone to '%s': %m", tz);
 502                 }
 503         }
 504
 505         if (!link->network->dhcp_critical) {
 506                 r = sd_dhcp_lease_get_lifetime(link->dhcp_lease, &lifetime);
 507                 if (r < 0) {
 508                         log_link_warning_errno(link, r, "DHCP error: no lifetime: %m");
 509                         return r;
 510                 }
 511         }
 512
 513         r = dhcp4_update_address(link, &address, &netmask, lifetime);
 514         if (r < 0) {
 515                 log_link_warning_errno(link, r, "Could not update IP address: %m");
 516                 link_enter_failed(link);
 517                 return r;
 518         }
 519
 520         return 0;
 521 }
 522 static void dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
 523         Link *link = userdata;
 524         int r = 0;
 525
 526         assert(link);
 527         assert(link->network);
 528         assert(link->manager);
 529
 530         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 531                 return;
 532
 533         switch (event) {
 534                 case SD_DHCP_CLIENT_EVENT_EXPIRED:
 535                 case SD_DHCP_CLIENT_EVENT_STOP:
 536                 case SD_DHCP_CLIENT_EVENT_IP_CHANGE:
 537                         if (link->network->dhcp_critical) {
 538                                 log_link_error(link, "DHCPv4 connection considered system critical, ignoring request to reconfigure it.");
 539                                 return;
 540                         }
 541
 542                         if (link->dhcp_lease) {
 543                                 r = dhcp_lease_lost(link);
 544                                 if (r < 0) {
 545                                         link_enter_failed(link);
 546                                         return;
 547                                 }
 548                         }
 549
 550                         if (event == SD_DHCP_CLIENT_EVENT_IP_CHANGE) {
 551                                 r = dhcp_lease_acquired(client, link);
 552                                 if (r < 0) {
 553                                         link_enter_failed(link);
 554                                         return;
 555                                 }
 556                         }
 557
 558                         break;
 559                 case SD_DHCP_CLIENT_EVENT_RENEW:
 560                         r = dhcp_lease_renew(client, link);
 561                         if (r < 0) {
 562                                 link_enter_failed(link);
 563                                 return;
 564                         }
 565                         break;
 566                 case SD_DHCP_CLIENT_EVENT_IP_ACQUIRE:
 567                         r = dhcp_lease_acquired(client, link);
 568                         if (r < 0) {
 569                                 link_enter_failed(link);
 570                                 return;
 571                         }
 572                         break;
 573                 default:
 574                         if (event < 0)
 575                                 log_link_warning_errno(link, event, "DHCP error: Client failed: %m");
 576                         else
 577                                 log_link_warning(link, "DHCP unknown event: %i", event);
 578                         break;
 579         }
 580
 581         return;
 582 }
 583
 584 static int dhcp4_set_hostname(Link *link) {
 585         _cleanup_free_ char *hostname = NULL;
 586         const char *hn;
 587         int r;
 588
 589         assert(link);
 590
 591         if (!link->network->dhcp_send_hostname)
 592                 hn = NULL;
 593         else if (link->network->dhcp_hostname)
 594                 hn = link->network->dhcp_hostname;
 595         else {
 596                 r = gethostname_strict(&hostname);
 597                 if (r < 0 && r != -ENXIO) /* ENXIO: no hostname set or hostname is "localhost" */
 598                         return r;
 599
 600                 hn = hostname;
 601         }
 602
 603         return sd_dhcp_client_set_hostname(link->dhcp_client, hn);
 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_configure(Link *link) {
 660         int r;
 661
 662         assert(link);
 663         assert(link->network);
 664         assert(link->network->dhcp & ADDRESS_FAMILY_IPV4);
 665
 666         if (!link->dhcp_client) {
 667                 r = sd_dhcp_client_new(&link->dhcp_client, link->network->dhcp_anonymize);
 668                 if (r < 0)
 669                         return r;
 670         }
 671
 672         r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
 673         if (r < 0)
 674                 return r;
 675
 676         r = sd_dhcp_client_set_mac(link->dhcp_client,
 677                                    (const uint8_t *) &link->mac,
 678                                    sizeof (link->mac), ARPHRD_ETHER);
 679         if (r < 0)
 680                 return r;
 681
 682         r = sd_dhcp_client_set_ifindex(link->dhcp_client, link->ifindex);
 683         if (r < 0)
 684                 return r;
 685
 686         r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp4_handler, link);
 687         if (r < 0)
 688                 return r;
 689
 690         r = sd_dhcp_client_set_request_broadcast(link->dhcp_client,
 691                                                  link->network->dhcp_broadcast);
 692         if (r < 0)
 693                 return r;
 694
 695         if (link->mtu) {
 696                 r = sd_dhcp_client_set_mtu(link->dhcp_client, link->mtu);
 697                 if (r < 0)
 698                         return r;
 699         }
 700
 701         if (link->network->dhcp_use_mtu) {
 702                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 703                                                       SD_DHCP_OPTION_INTERFACE_MTU);
 704                 if (r < 0)
 705                         return r;
 706         }
 707
 708         /* NOTE: even if this variable is called "use", it also "sends" PRL
 709          * options, maybe there should be a different configuration variable
 710          * to send or not route options?. */
 711         /* NOTE: when using Anonymize=yes, routes PRL options are sent
 712          * by default, so they don't need to be added here. */
 713         if (link->network->dhcp_use_routes && !link->network->dhcp_anonymize) {
 714                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 715                                                       SD_DHCP_OPTION_STATIC_ROUTE);
 716                 if (r < 0)
 717                         return r;
 718                 r = sd_dhcp_client_set_request_option(link->dhcp_client,
 719                                                       SD_DHCP_OPTION_CLASSLESS_STATIC_ROUTE);
 720                 if (r < 0)
 721                         return r;
 722         }
 723
 724         if (link->network->dhcp_use_ntp) {
 725                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NTP_SERVER);
 726                 if (r < 0)
 727                         return r;
 728         }
 729
 730         if (link->network->dhcp_use_timezone) {
 731                 r = sd_dhcp_client_set_request_option(link->dhcp_client, SD_DHCP_OPTION_NEW_TZDB_TIMEZONE);
 732                 if (r < 0)
 733                         return r;
 734         }
 735
 736         r = dhcp4_set_hostname(link);
 737         if (r < 0)
 738                 return r;
 739
 740         if (link->network->dhcp_vendor_class_identifier) {
 741                 r = sd_dhcp_client_set_vendor_class_identifier(link->dhcp_client,
 742                                                                link->network->dhcp_vendor_class_identifier);
 743                 if (r < 0)
 744                         return r;
 745         }
 746
 747         if (link->network->dhcp_user_class) {
 748                 r = sd_dhcp_client_set_user_class(link->dhcp_client, (const char **) link->network->dhcp_user_class);
 749                 if (r < 0)
 750                         return r;
 751         }
 752
 753         if (link->network->dhcp_client_port) {
 754                 r = sd_dhcp_client_set_client_port(link->dhcp_client, link->network->dhcp_client_port);
 755                 if (r < 0)
 756                         return r;
 757         }
 758
 759         switch (link->network->dhcp_client_identifier) {
 760         case DHCP_CLIENT_ID_DUID: {
 761                 /* If configured, apply user specified DUID and/or IAID */
 762                 const DUID *duid = link_duid(link);
 763
 764                 r = sd_dhcp_client_set_iaid_duid(link->dhcp_client,
 765                                                  link->network->iaid,
 766                                                  duid->type,
 767                                                  duid->raw_data_len > 0 ? duid->raw_data : NULL,
 768                                                  duid->raw_data_len);
 769                 if (r < 0)
 770                         return r;
 771                 break;
 772         }
 773         case DHCP_CLIENT_ID_DUID_ONLY: {
 774                 /* If configured, apply user specified DUID */
 775                 const DUID *duid = link_duid(link);
 776
 777                 r = sd_dhcp_client_set_duid(link->dhcp_client,
 778                                             duid->type,
 779                                             duid->raw_data_len > 0 ? duid->raw_data : NULL,
 780                                             duid->raw_data_len);
 781                 if (r < 0)
 782                         return r;
 783                 break;
 784         }
 785         case DHCP_CLIENT_ID_MAC:
 786                 r = sd_dhcp_client_set_client_id(link->dhcp_client,
 787                                                  ARPHRD_ETHER,
 788                                                  (const uint8_t *) &link->mac,
 789                                                  sizeof(link->mac));
 790                 if (r < 0)
 791                         return r;
 792                 break;
 793         default:
 794                 assert_not_reached("Unknown client identifier type.");
 795         }
 796
 797         return 0;
 798 }