src/network/networkd-ndisc.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright © 2014 Intel Corporation. All rights reserved.
   4 ***/
   5
   6 #include <netinet/icmp6.h>
   7 #include <arpa/inet.h>
   8
   9 #include "sd-ndisc.h"
  10
  11 #include "networkd-ndisc.h"
  12 #include "networkd-route.h"
  13 #include "strv.h"
  14
  15 #define NDISC_DNSSL_MAX 64U
  16 #define NDISC_RDNSS_MAX 64U
  17 #define NDISC_PREFIX_LFT_MIN 7200U
  18
  19 static int ndisc_netlink_message_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
  20         int r;
  21
  22         assert(link);
  23         assert(link->ndisc_messages > 0);
  24
  25         link->ndisc_messages--;
  26
  27         r = sd_netlink_message_get_errno(m);
  28         if (r < 0 && r != -EEXIST)
  29                 log_link_error_errno(link, r, "Could not set NDisc route or address: %m");
  30
  31         if (link->ndisc_messages == 0) {
  32                 link->ndisc_configured = true;
  33                 link_check_ready(link);
  34         }
  35
  36         return 1;
  37 }
  38
  39 static int ndisc_router_process_default(Link *link, sd_ndisc_router *rt) {
  40         _cleanup_(route_freep) Route *route = NULL;
  41         struct in6_addr gateway;
  42         uint16_t lifetime;
  43         unsigned preference;
  44         uint32_t mtu;
  45         usec_t time_now;
  46         int r;
  47         Address *address;
  48         Iterator i;
  49
  50         assert(link);
  51         assert(rt);
  52
  53         r = sd_ndisc_router_get_lifetime(rt, &lifetime);
  54         if (r < 0)
  55                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
  56
  57         if (lifetime == 0) /* not a default router */
  58                 return 0;
  59
  60         r = sd_ndisc_router_get_address(rt, &gateway);
  61         if (r < 0)
  62                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
  63
  64         SET_FOREACH(address, link->addresses, i)
  65                 if (!memcmp(&gateway, &address->in_addr.in6, sizeof(address->in_addr.in6))) {
  66                         char buffer[INET6_ADDRSTRLEN];
  67
  68                         log_link_debug(link, "No NDisc route added, gateway %s matches local address",
  69                                        inet_ntop(AF_INET6,
  70                                                  &address->in_addr.in6,
  71                                                  buffer, sizeof(buffer)));
  72                         return 0;
  73                 }
  74
  75         SET_FOREACH(address, link->addresses_foreign, i)
  76                 if (!memcmp(&gateway, &address->in_addr.in6, sizeof(address->in_addr.in6))) {
  77                         char buffer[INET6_ADDRSTRLEN];
  78
  79                         log_link_debug(link, "No NDisc route added, gateway %s matches local address",
  80                                        inet_ntop(AF_INET6,
  81                                                  &address->in_addr.in6,
  82                                                  buffer, sizeof(buffer)));
  83                         return 0;
  84                 }
  85
  86         r = sd_ndisc_router_get_preference(rt, &preference);
  87         if (r < 0)
  88                 return log_link_warning_errno(link, r, "Failed to get default router preference from RA: %m");
  89
  90         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
  91         if (r < 0)
  92                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
  93
  94         r = sd_ndisc_router_get_mtu(rt, &mtu);
  95         if (r == -ENODATA)
  96                 mtu = 0;
  97         else if (r < 0)
  98                 return log_link_warning_errno(link, r, "Failed to get default router MTU from RA: %m");
  99
 100         r = route_new(&route);
 101         if (r < 0)
 102                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 103
 104         route->family = AF_INET6;
 105         route->table = link->network->ipv6_accept_ra_route_table;
 106         route->priority = link->network->dhcp_route_metric;
 107         route->protocol = RTPROT_RA;
 108         route->pref = preference;
 109         route->gw.in6 = gateway;
 110         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 111         route->mtu = mtu;
 112
 113         r = route_configure(route, link, ndisc_netlink_message_handler);
 114         if (r < 0) {
 115                 log_link_warning_errno(link, r, "Could not set default route: %m");
 116                 link_enter_failed(link);
 117                 return r;
 118         }
 119
 120         link->ndisc_messages++;
 121
 122         return 0;
 123 }
 124
 125 static int ndisc_router_process_autonomous_prefix(Link *link, sd_ndisc_router *rt) {
 126         _cleanup_(address_freep) Address *address = NULL;
 127         Address *existing_address;
 128         uint32_t lifetime_valid, lifetime_preferred, lifetime_remaining;
 129         usec_t time_now;
 130         unsigned prefixlen;
 131         int r;
 132
 133         assert(link);
 134         assert(rt);
 135
 136         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 137         if (r < 0)
 138                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 139
 140         r = sd_ndisc_router_prefix_get_prefixlen(rt, &prefixlen);
 141         if (r < 0)
 142                 return log_link_error_errno(link, r, "Failed to get prefix length: %m");
 143
 144         r = sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime_valid);
 145         if (r < 0)
 146                 return log_link_error_errno(link, r, "Failed to get prefix valid lifetime: %m");
 147
 148         r = sd_ndisc_router_prefix_get_preferred_lifetime(rt, &lifetime_preferred);
 149         if (r < 0)
 150                 return log_link_error_errno(link, r, "Failed to get prefix preferred lifetime: %m");
 151
 152         /* The preferred lifetime is never greater than the valid lifetime */
 153         if (lifetime_preferred > lifetime_valid)
 154                 return 0;
 155
 156         r = address_new(&address);
 157         if (r < 0)
 158                 return log_link_error_errno(link, r, "Could not allocate address: %m");
 159
 160         address->family = AF_INET6;
 161         r = sd_ndisc_router_prefix_get_address(rt, &address->in_addr.in6);
 162         if (r < 0)
 163                 return log_link_error_errno(link, r, "Failed to get prefix address: %m");
 164
 165         if (in_addr_is_null(AF_INET6, (const union in_addr_union *) &link->network->ipv6_token) == 0)
 166                 memcpy(((char *)&address->in_addr.in6) + 8, ((char *)&link->network->ipv6_token) + 8, 8);
 167         else {
 168                 /* see RFC4291 section 2.5.1 */
 169                 address->in_addr.in6.s6_addr[8]  = link->mac.ether_addr_octet[0];
 170                 address->in_addr.in6.s6_addr[8] ^= 1 << 1;
 171                 address->in_addr.in6.s6_addr[9]  = link->mac.ether_addr_octet[1];
 172                 address->in_addr.in6.s6_addr[10] = link->mac.ether_addr_octet[2];
 173                 address->in_addr.in6.s6_addr[11] = 0xff;
 174                 address->in_addr.in6.s6_addr[12] = 0xfe;
 175                 address->in_addr.in6.s6_addr[13] = link->mac.ether_addr_octet[3];
 176                 address->in_addr.in6.s6_addr[14] = link->mac.ether_addr_octet[4];
 177                 address->in_addr.in6.s6_addr[15] = link->mac.ether_addr_octet[5];
 178         }
 179         address->prefixlen = prefixlen;
 180         address->flags = IFA_F_NOPREFIXROUTE|IFA_F_MANAGETEMPADDR;
 181         address->cinfo.ifa_prefered = lifetime_preferred;
 182
 183         /* see RFC4862 section 5.5.3.e */
 184         r = address_get(link, address->family, &address->in_addr, address->prefixlen, &existing_address);
 185         if (r > 0) {
 186                 lifetime_remaining = existing_address->cinfo.tstamp / 100 + existing_address->cinfo.ifa_valid - time_now / USEC_PER_SEC;
 187                 if (lifetime_valid > NDISC_PREFIX_LFT_MIN || lifetime_valid > lifetime_remaining)
 188                         address->cinfo.ifa_valid = lifetime_valid;
 189                 else if (lifetime_remaining <= NDISC_PREFIX_LFT_MIN)
 190                         address->cinfo.ifa_valid = lifetime_remaining;
 191                 else
 192                         address->cinfo.ifa_valid = NDISC_PREFIX_LFT_MIN;
 193         } else if (lifetime_valid > 0)
 194                 address->cinfo.ifa_valid = lifetime_valid;
 195         else
 196                 return 0; /* see RFC4862 section 5.5.3.d */
 197
 198         if (address->cinfo.ifa_valid == 0)
 199                 return 0;
 200
 201         r = address_configure(address, link, ndisc_netlink_message_handler, true);
 202         if (r < 0) {
 203                 log_link_warning_errno(link, r, "Could not set SLAAC address: %m");
 204                 link_enter_failed(link);
 205                 return r;
 206         }
 207
 208         link->ndisc_messages++;
 209
 210         return 0;
 211 }
 212
 213 static int ndisc_router_process_onlink_prefix(Link *link, sd_ndisc_router *rt) {
 214         _cleanup_(route_freep) Route *route = NULL;
 215         usec_t time_now;
 216         uint32_t lifetime;
 217         unsigned prefixlen;
 218         int r;
 219
 220         assert(link);
 221         assert(rt);
 222
 223         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 224         if (r < 0)
 225                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 226
 227         r = sd_ndisc_router_prefix_get_prefixlen(rt, &prefixlen);
 228         if (r < 0)
 229                 return log_link_error_errno(link, r, "Failed to get prefix length: %m");
 230
 231         r = sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime);
 232         if (r < 0)
 233                 return log_link_error_errno(link, r, "Failed to get prefix lifetime: %m");
 234
 235         r = route_new(&route);
 236         if (r < 0)
 237                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 238
 239         route->family = AF_INET6;
 240         route->table = link->network->ipv6_accept_ra_route_table;
 241         route->priority = link->network->dhcp_route_metric;
 242         route->protocol = RTPROT_RA;
 243         route->flags = RTM_F_PREFIX;
 244         route->dst_prefixlen = prefixlen;
 245         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 246
 247         r = sd_ndisc_router_prefix_get_address(rt, &route->dst.in6);
 248         if (r < 0)
 249                 return log_link_error_errno(link, r, "Failed to get prefix address: %m");
 250
 251         r = route_configure(route, link, ndisc_netlink_message_handler);
 252         if (r < 0) {
 253                 log_link_warning_errno(link, r, "Could not set prefix route: %m");
 254                 link_enter_failed(link);
 255                 return r;
 256         }
 257
 258         link->ndisc_messages++;
 259
 260         return 0;
 261 }
 262
 263 static int ndisc_router_process_route(Link *link, sd_ndisc_router *rt) {
 264         _cleanup_(route_freep) Route *route = NULL;
 265         struct in6_addr gateway;
 266         uint32_t lifetime;
 267         unsigned preference, prefixlen;
 268         usec_t time_now;
 269         int r;
 270
 271         assert(link);
 272
 273         r = sd_ndisc_router_route_get_lifetime(rt, &lifetime);
 274         if (r < 0)
 275                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
 276
 277         if (lifetime == 0)
 278                 return 0;
 279
 280         r = sd_ndisc_router_get_address(rt, &gateway);
 281         if (r < 0)
 282                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
 283
 284         r = sd_ndisc_router_route_get_prefixlen(rt, &prefixlen);
 285         if (r < 0)
 286                 return log_link_warning_errno(link, r, "Failed to get route prefix length: %m");
 287
 288         r = sd_ndisc_router_route_get_preference(rt, &preference);
 289         if (r < 0)
 290                 return log_link_warning_errno(link, r, "Failed to get default router preference from RA: %m");
 291
 292         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 293         if (r < 0)
 294                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 295
 296         r = route_new(&route);
 297         if (r < 0)
 298                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 299
 300         route->family = AF_INET6;
 301         route->table = link->network->ipv6_accept_ra_route_table;
 302         route->protocol = RTPROT_RA;
 303         route->pref = preference;
 304         route->gw.in6 = gateway;
 305         route->dst_prefixlen = prefixlen;
 306         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 307
 308         r = sd_ndisc_router_route_get_address(rt, &route->dst.in6);
 309         if (r < 0)
 310                 return log_link_error_errno(link, r, "Failed to get route address: %m");
 311
 312         r = route_configure(route, link, ndisc_netlink_message_handler);
 313         if (r < 0) {
 314                 log_link_warning_errno(link, r, "Could not set additional route: %m");
 315                 link_enter_failed(link);
 316                 return r;
 317         }
 318
 319         link->ndisc_messages++;
 320
 321         return 0;
 322 }
 323
 324 static void ndisc_rdnss_hash_func(const NDiscRDNSS *x, struct siphash *state) {
 325         siphash24_compress(&x->address, sizeof(x->address), state);
 326 }
 327
 328 static int ndisc_rdnss_compare_func(const NDiscRDNSS *a, const NDiscRDNSS *b) {
 329         return memcmp(&a->address, &b->address, sizeof(a->address));
 330 }
 331
 332 DEFINE_PRIVATE_HASH_OPS(ndisc_rdnss_hash_ops, NDiscRDNSS, ndisc_rdnss_hash_func, ndisc_rdnss_compare_func);
 333
 334 static int ndisc_router_process_rdnss(Link *link, sd_ndisc_router *rt) {
 335         uint32_t lifetime;
 336         const struct in6_addr *a;
 337         usec_t time_now;
 338         int i, n, r;
 339
 340         assert(link);
 341         assert(rt);
 342
 343         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 344         if (r < 0)
 345                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 346
 347         r = sd_ndisc_router_rdnss_get_lifetime(rt, &lifetime);
 348         if (r < 0)
 349                 return log_link_warning_errno(link, r, "Failed to get RDNSS lifetime: %m");
 350
 351         n = sd_ndisc_router_rdnss_get_addresses(rt, &a);
 352         if (n < 0)
 353                 return log_link_warning_errno(link, n, "Failed to get RDNSS addresses: %m");
 354
 355         for (i = 0; i < n; i++) {
 356                 _cleanup_free_ NDiscRDNSS *x = NULL;
 357                 NDiscRDNSS d = {
 358                         .address = a[i],
 359                 }, *y;
 360
 361                 if (lifetime == 0) {
 362                         (void) set_remove(link->ndisc_rdnss, &d);
 363                         link_dirty(link);
 364                         continue;
 365                 }
 366
 367                 y = set_get(link->ndisc_rdnss, &d);
 368                 if (y) {
 369                         y->valid_until = time_now + lifetime * USEC_PER_SEC;
 370                         continue;
 371                 }
 372
 373                 ndisc_vacuum(link);
 374
 375                 if (set_size(link->ndisc_rdnss) >= NDISC_RDNSS_MAX) {
 376                         log_link_warning(link, "Too many RDNSS records per link, ignoring.");
 377                         continue;
 378                 }
 379
 380                 r = set_ensure_allocated(&link->ndisc_rdnss, &ndisc_rdnss_hash_ops);
 381                 if (r < 0)
 382                         return log_oom();
 383
 384                 x = new(NDiscRDNSS, 1);
 385                 if (!x)
 386                         return log_oom();
 387
 388                 *x = (NDiscRDNSS) {
 389                         .address = a[i],
 390                         .valid_until = time_now + lifetime * USEC_PER_SEC,
 391                 };
 392
 393                 r = set_put(link->ndisc_rdnss, x);
 394                 if (r < 0)
 395                         return log_oom();
 396
 397                 TAKE_PTR(x);
 398
 399                 assert(r > 0);
 400                 link_dirty(link);
 401         }
 402
 403         return 0;
 404 }
 405
 406 static void ndisc_dnssl_hash_func(const NDiscDNSSL *x, struct siphash *state) {
 407         siphash24_compress(NDISC_DNSSL_DOMAIN(x), strlen(NDISC_DNSSL_DOMAIN(x)), state);
 408 }
 409
 410 static int ndisc_dnssl_compare_func(const NDiscDNSSL *a, const NDiscDNSSL *b) {
 411         return strcmp(NDISC_DNSSL_DOMAIN(a), NDISC_DNSSL_DOMAIN(b));
 412 }
 413
 414 DEFINE_PRIVATE_HASH_OPS(ndisc_dnssl_hash_ops, NDiscDNSSL, ndisc_dnssl_hash_func, ndisc_dnssl_compare_func);
 415
 416 static void ndisc_router_process_dnssl(Link *link, sd_ndisc_router *rt) {
 417         _cleanup_strv_free_ char **l = NULL;
 418         uint32_t lifetime;
 419         usec_t time_now;
 420         char **i;
 421         int r;
 422
 423         assert(link);
 424         assert(rt);
 425
 426         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 427         if (r < 0) {
 428                 log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 429                 return;
 430         }
 431
 432         r = sd_ndisc_router_dnssl_get_lifetime(rt, &lifetime);
 433         if (r < 0) {
 434                 log_link_warning_errno(link, r, "Failed to get RDNSS lifetime: %m");
 435                 return;
 436         }
 437
 438         r = sd_ndisc_router_dnssl_get_domains(rt, &l);
 439         if (r < 0) {
 440                 log_link_warning_errno(link, r, "Failed to get RDNSS addresses: %m");
 441                 return;
 442         }
 443
 444         STRV_FOREACH(i, l) {
 445                 _cleanup_free_ NDiscDNSSL *s;
 446                 NDiscDNSSL *x;
 447
 448                 s = malloc0(ALIGN(sizeof(NDiscDNSSL)) + strlen(*i) + 1);
 449                 if (!s) {
 450                         log_oom();
 451                         return;
 452                 }
 453
 454                 strcpy(NDISC_DNSSL_DOMAIN(s), *i);
 455
 456                 if (lifetime == 0) {
 457                         (void) set_remove(link->ndisc_dnssl, s);
 458                         link_dirty(link);
 459                         continue;
 460                 }
 461
 462                 x = set_get(link->ndisc_dnssl, s);
 463                 if (x) {
 464                         x->valid_until = time_now + lifetime * USEC_PER_SEC;
 465                         continue;
 466                 }
 467
 468                 ndisc_vacuum(link);
 469
 470                 if (set_size(link->ndisc_dnssl) >= NDISC_DNSSL_MAX) {
 471                         log_link_warning(link, "Too many DNSSL records per link, ignoring.");
 472                         continue;
 473                 }
 474
 475                 r = set_ensure_allocated(&link->ndisc_dnssl, &ndisc_dnssl_hash_ops);
 476                 if (r < 0) {
 477                         log_oom();
 478                         return;
 479                 }
 480
 481                 s->valid_until = time_now + lifetime * USEC_PER_SEC;
 482
 483                 r = set_put(link->ndisc_dnssl, s);
 484                 if (r < 0) {
 485                         log_oom();
 486                         return;
 487                 }
 488
 489                 s = NULL;
 490                 assert(r > 0);
 491                 link_dirty(link);
 492         }
 493 }
 494
 495 static void ndisc_router_process_options(Link *link, sd_ndisc_router *rt) {
 496         int r;
 497
 498         assert(link);
 499         assert(rt);
 500
 501         r = sd_ndisc_router_option_rewind(rt);
 502         for (;;) {
 503                 uint8_t type;
 504
 505                 if (r < 0) {
 506                         log_link_warning_errno(link, r, "Failed to iterate through options: %m");
 507                         return;
 508                 }
 509                 if (r == 0) /* EOF */
 510                         break;
 511
 512                 r = sd_ndisc_router_option_get_type(rt, &type);
 513                 if (r < 0) {
 514                         log_link_warning_errno(link, r, "Failed to get RA option type: %m");
 515                         return;
 516                 }
 517
 518                 switch (type) {
 519
 520                 case SD_NDISC_OPTION_PREFIX_INFORMATION: {
 521                         uint8_t flags;
 522
 523                         r = sd_ndisc_router_prefix_get_flags(rt, &flags);
 524                         if (r < 0) {
 525                                 log_link_warning_errno(link, r, "Failed to get RA prefix flags: %m");
 526                                 return;
 527                         }
 528
 529                         if (flags & ND_OPT_PI_FLAG_ONLINK)
 530                                 (void) ndisc_router_process_onlink_prefix(link, rt);
 531                         if (flags & ND_OPT_PI_FLAG_AUTO)
 532                                 (void) ndisc_router_process_autonomous_prefix(link, rt);
 533
 534                         break;
 535                 }
 536
 537                 case SD_NDISC_OPTION_ROUTE_INFORMATION:
 538                         (void) ndisc_router_process_route(link, rt);
 539                         break;
 540
 541                 case SD_NDISC_OPTION_RDNSS:
 542                         if (link->network->ipv6_accept_ra_use_dns)
 543                                 (void) ndisc_router_process_rdnss(link, rt);
 544                         break;
 545
 546                 case SD_NDISC_OPTION_DNSSL:
 547                         if (link->network->ipv6_accept_ra_use_dns)
 548                                 (void) ndisc_router_process_dnssl(link, rt);
 549                         break;
 550                 }
 551
 552                 r = sd_ndisc_router_option_next(rt);
 553         }
 554 }
 555
 556 static int ndisc_router_handler(Link *link, sd_ndisc_router *rt) {
 557         uint64_t flags;
 558         int r = 0;
 559
 560         assert(link);
 561         assert(link->network);
 562         assert(link->manager);
 563         assert(rt);
 564
 565         r = sd_ndisc_router_get_flags(rt, &flags);
 566         if (r < 0)
 567                 return log_link_warning_errno(link, r, "Failed to get RA flags: %m");
 568
 569         if (flags & (ND_RA_FLAG_MANAGED | ND_RA_FLAG_OTHER)) {
 570                 /* (re)start DHCPv6 client in stateful or stateless mode according to RA flags */
 571                 r = dhcp6_request_address(link, !(flags & ND_RA_FLAG_MANAGED));
 572                 if (r < 0 && r != -EBUSY)
 573                         log_link_warning_errno(link, r, "Could not acquire DHCPv6 lease on NDisc request: %m");
 574                 else {
 575                         log_link_debug(link, "Acquiring DHCPv6 lease on NDisc request");
 576                         r = 0;
 577                 }
 578         }
 579
 580         ndisc_router_process_default(link, rt);
 581         ndisc_router_process_options(link, rt);
 582
 583         return r;
 584 }
 585
 586 static void ndisc_handler(sd_ndisc *nd, sd_ndisc_event event, sd_ndisc_router *rt, void *userdata) {
 587         Link *link = userdata;
 588
 589         assert(link);
 590
 591         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 592                 return;
 593
 594         switch (event) {
 595
 596         case SD_NDISC_EVENT_ROUTER:
 597                 (void) ndisc_router_handler(link, rt);
 598                 break;
 599
 600         case SD_NDISC_EVENT_TIMEOUT:
 601                 link->ndisc_configured = true;
 602                 link_check_ready(link);
 603
 604                 break;
 605         default:
 606                 log_link_warning(link, "IPv6 Neighbor Discovery unknown event: %d", event);
 607         }
 608 }
 609
 610 int ndisc_configure(Link *link) {
 611         int r;
 612
 613         assert(link);
 614
 615         r = sd_ndisc_new(&link->ndisc);
 616         if (r < 0)
 617                 return r;
 618
 619         r = sd_ndisc_attach_event(link->ndisc, NULL, 0);
 620         if (r < 0)
 621                 return r;
 622
 623         r = sd_ndisc_set_mac(link->ndisc, &link->mac);
 624         if (r < 0)
 625                 return r;
 626
 627         r = sd_ndisc_set_ifindex(link->ndisc, link->ifindex);
 628         if (r < 0)
 629                 return r;
 630
 631         r = sd_ndisc_set_callback(link->ndisc, ndisc_handler, link);
 632         if (r < 0)
 633                 return r;
 634
 635         return 0;
 636 }
 637
 638 void ndisc_vacuum(Link *link) {
 639         NDiscRDNSS *r;
 640         NDiscDNSSL *d;
 641         Iterator i;
 642         usec_t time_now;
 643
 644         assert(link);
 645
 646         /* Removes all RDNSS and DNSSL entries whose validity time has passed */
 647
 648         time_now = now(clock_boottime_or_monotonic());
 649
 650         SET_FOREACH(r, link->ndisc_rdnss, i)
 651                 if (r->valid_until < time_now) {
 652                         free(set_remove(link->ndisc_rdnss, r));
 653                         link_dirty(link);
 654                 }
 655
 656         SET_FOREACH(d, link->ndisc_dnssl, i)
 657                 if (d->valid_until < time_now) {
 658                         free(set_remove(link->ndisc_dnssl, d));
 659                         link_dirty(link);
 660                 }
 661 }
 662
 663 void ndisc_flush(Link *link) {
 664         assert(link);
 665
 666         /* Removes all RDNSS and DNSSL entries, without exception */
 667
 668         link->ndisc_rdnss = set_free_free(link->ndisc_rdnss);
 669         link->ndisc_dnssl = set_free_free(link->ndisc_dnssl);
 670 }