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_route_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
  20         Link *link = userdata;
  21         int r;
  22
  23         assert(link);
  24         assert(link->ndisc_messages > 0);
  25
  26         link->ndisc_messages--;
  27
  28         r = sd_netlink_message_get_errno(m);
  29         if (r < 0 && r != -EEXIST)
  30                 log_link_error_errno(link, r, "Could not set NDisc route or address: %m");
  31
  32         if (link->ndisc_messages == 0) {
  33                 link->ndisc_configured = true;
  34                 link_check_ready(link);
  35         }
  36
  37         return 1;
  38 }
  39
  40 static int ndisc_router_process_default(Link *link, sd_ndisc_router *rt) {
  41         _cleanup_(route_freep) Route *route = NULL;
  42         struct in6_addr gateway;
  43         uint16_t lifetime;
  44         unsigned preference;
  45         uint32_t mtu;
  46         usec_t time_now;
  47         int r;
  48         Address *address;
  49         Iterator i;
  50
  51         assert(link);
  52         assert(rt);
  53
  54         r = sd_ndisc_router_get_lifetime(rt, &lifetime);
  55         if (r < 0)
  56                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
  57
  58         if (lifetime == 0) /* not a default router */
  59                 return 0;
  60
  61         r = sd_ndisc_router_get_address(rt, &gateway);
  62         if (r < 0)
  63                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
  64
  65         SET_FOREACH(address, link->addresses, i)
  66                 if (!memcmp(&gateway, &address->in_addr.in6, sizeof(address->in_addr.in6))) {
  67                         char buffer[INET6_ADDRSTRLEN];
  68
  69                         log_link_debug(link, "No NDisc route added, gateway %s matches local address",
  70                                        inet_ntop(AF_INET6,
  71                                                  &address->in_addr.in6,
  72                                                  buffer, sizeof(buffer)));
  73                         return 0;
  74                 }
  75
  76         SET_FOREACH(address, link->addresses_foreign, i)
  77                 if (!memcmp(&gateway, &address->in_addr.in6, sizeof(address->in_addr.in6))) {
  78                         char buffer[INET6_ADDRSTRLEN];
  79
  80                         log_link_debug(link, "No NDisc route added, gateway %s matches local address",
  81                                        inet_ntop(AF_INET6,
  82                                                  &address->in_addr.in6,
  83                                                  buffer, sizeof(buffer)));
  84                         return 0;
  85                 }
  86
  87         r = sd_ndisc_router_get_preference(rt, &preference);
  88         if (r < 0)
  89                 return log_link_warning_errno(link, r, "Failed to get default router preference from RA: %m");
  90
  91         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
  92         if (r < 0)
  93                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
  94
  95         r = sd_ndisc_router_get_mtu(rt, &mtu);
  96         if (r == -ENODATA)
  97                 mtu = 0;
  98         else if (r < 0)
  99                 return log_link_warning_errno(link, r, "Failed to get default router MTU from RA: %m");
 100
 101         r = route_new(&route);
 102         if (r < 0)
 103                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 104
 105         route->family = AF_INET6;
 106         route->table = link->network->ipv6_accept_ra_route_table;
 107         route->priority = link->network->dhcp_route_metric;
 108         route->protocol = RTPROT_RA;
 109         route->pref = preference;
 110         route->gw.in6 = gateway;
 111         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 112         route->mtu = mtu;
 113
 114         r = route_configure(route, link, ndisc_route_handler);
 115         if (r < 0) {
 116                 log_link_warning_errno(link, r, "Could not set default route: %m");
 117                 link_enter_failed(link);
 118                 return r;
 119         }
 120
 121         link->ndisc_messages++;
 122
 123         return 0;
 124 }
 125
 126 static int ndisc_router_process_autonomous_prefix(Link *link, sd_ndisc_router *rt) {
 127         _cleanup_(address_freep) Address *address = NULL;
 128         Address *existing_address;
 129         uint32_t lifetime_valid, lifetime_preferred, lifetime_remaining;
 130         usec_t time_now;
 131         unsigned prefixlen;
 132         int r;
 133
 134         assert(link);
 135         assert(rt);
 136
 137         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 138         if (r < 0)
 139                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 140
 141         r = sd_ndisc_router_prefix_get_prefixlen(rt, &prefixlen);
 142         if (r < 0)
 143                 return log_link_error_errno(link, r, "Failed to get prefix length: %m");
 144
 145         r = sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime_valid);
 146         if (r < 0)
 147                 return log_link_error_errno(link, r, "Failed to get prefix valid lifetime: %m");
 148
 149         r = sd_ndisc_router_prefix_get_preferred_lifetime(rt, &lifetime_preferred);
 150         if (r < 0)
 151                 return log_link_error_errno(link, r, "Failed to get prefix preferred lifetime: %m");
 152
 153         /* The preferred lifetime is never greater than the valid lifetime */
 154         if (lifetime_preferred > lifetime_valid)
 155                 return 0;
 156
 157         r = address_new(&address);
 158         if (r < 0)
 159                 return log_link_error_errno(link, r, "Could not allocate address: %m");
 160
 161         address->family = AF_INET6;
 162         r = sd_ndisc_router_prefix_get_address(rt, &address->in_addr.in6);
 163         if (r < 0)
 164                 return log_link_error_errno(link, r, "Failed to get prefix address: %m");
 165
 166         if (in_addr_is_null(AF_INET6, (const union in_addr_union *) &link->network->ipv6_token) == 0)
 167                 memcpy(((char *)&address->in_addr.in6) + 8, ((char *)&link->network->ipv6_token) + 8, 8);
 168         else {
 169                 /* see RFC4291 section 2.5.1 */
 170                 address->in_addr.in6.s6_addr[8]  = link->mac.ether_addr_octet[0];
 171                 address->in_addr.in6.s6_addr[8] ^= 1 << 1;
 172                 address->in_addr.in6.s6_addr[9]  = link->mac.ether_addr_octet[1];
 173                 address->in_addr.in6.s6_addr[10] = link->mac.ether_addr_octet[2];
 174                 address->in_addr.in6.s6_addr[11] = 0xff;
 175                 address->in_addr.in6.s6_addr[12] = 0xfe;
 176                 address->in_addr.in6.s6_addr[13] = link->mac.ether_addr_octet[3];
 177                 address->in_addr.in6.s6_addr[14] = link->mac.ether_addr_octet[4];
 178                 address->in_addr.in6.s6_addr[15] = link->mac.ether_addr_octet[5];
 179         }
 180         address->prefixlen = prefixlen;
 181         address->flags = IFA_F_NOPREFIXROUTE|IFA_F_MANAGETEMPADDR;
 182         address->cinfo.ifa_prefered = lifetime_preferred;
 183
 184         /* see RFC4862 section 5.5.3.e */
 185         r = address_get(link, address->family, &address->in_addr, address->prefixlen, &existing_address);
 186         if (r > 0) {
 187                 lifetime_remaining = existing_address->cinfo.tstamp / 100 + existing_address->cinfo.ifa_valid - time_now / USEC_PER_SEC;
 188                 if (lifetime_valid > NDISC_PREFIX_LFT_MIN || lifetime_valid > lifetime_remaining)
 189                         address->cinfo.ifa_valid = lifetime_valid;
 190                 else if (lifetime_remaining <= NDISC_PREFIX_LFT_MIN)
 191                         address->cinfo.ifa_valid = lifetime_remaining;
 192                 else
 193                         address->cinfo.ifa_valid = NDISC_PREFIX_LFT_MIN;
 194         } else if (lifetime_valid > 0)
 195                 address->cinfo.ifa_valid = lifetime_valid;
 196         else
 197                 return 0; /* see RFC4862 section 5.5.3.d */
 198
 199         if (address->cinfo.ifa_valid == 0)
 200                 return 0;
 201
 202         r = address_configure(address, link, ndisc_route_handler, true);
 203         if (r < 0) {
 204                 log_link_warning_errno(link, r, "Could not set SLAAC address: %m");
 205                 link_enter_failed(link);
 206                 return r;
 207         }
 208
 209         link->ndisc_messages++;
 210
 211         return 0;
 212 }
 213
 214 static int ndisc_router_process_onlink_prefix(Link *link, sd_ndisc_router *rt) {
 215         _cleanup_(route_freep) Route *route = NULL;
 216         usec_t time_now;
 217         uint32_t lifetime;
 218         unsigned prefixlen;
 219         int r;
 220
 221         assert(link);
 222         assert(rt);
 223
 224         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 225         if (r < 0)
 226                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 227
 228         r = sd_ndisc_router_prefix_get_prefixlen(rt, &prefixlen);
 229         if (r < 0)
 230                 return log_link_error_errno(link, r, "Failed to get prefix length: %m");
 231
 232         r = sd_ndisc_router_prefix_get_valid_lifetime(rt, &lifetime);
 233         if (r < 0)
 234                 return log_link_error_errno(link, r, "Failed to get prefix lifetime: %m");
 235
 236         r = route_new(&route);
 237         if (r < 0)
 238                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 239
 240         route->family = AF_INET6;
 241         route->table = link->network->ipv6_accept_ra_route_table;
 242         route->priority = link->network->dhcp_route_metric;
 243         route->protocol = RTPROT_RA;
 244         route->flags = RTM_F_PREFIX;
 245         route->dst_prefixlen = prefixlen;
 246         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 247
 248         r = sd_ndisc_router_prefix_get_address(rt, &route->dst.in6);
 249         if (r < 0)
 250                 return log_link_error_errno(link, r, "Failed to get prefix address: %m");
 251
 252         r = route_configure(route, link, ndisc_route_handler);
 253         if (r < 0) {
 254                 log_link_warning_errno(link, r, "Could not set prefix route: %m");
 255                 link_enter_failed(link);
 256                 return r;
 257         }
 258
 259         link->ndisc_messages++;
 260
 261         return 0;
 262 }
 263
 264 static int ndisc_router_process_route(Link *link, sd_ndisc_router *rt) {
 265         _cleanup_(route_freep) Route *route = NULL;
 266         struct in6_addr gateway;
 267         uint32_t lifetime;
 268         unsigned preference, prefixlen;
 269         usec_t time_now;
 270         int r;
 271
 272         assert(link);
 273
 274         r = sd_ndisc_router_route_get_lifetime(rt, &lifetime);
 275         if (r < 0)
 276                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
 277
 278         if (lifetime == 0)
 279                 return 0;
 280
 281         r = sd_ndisc_router_get_address(rt, &gateway);
 282         if (r < 0)
 283                 return log_link_warning_errno(link, r, "Failed to get gateway address from RA: %m");
 284
 285         r = sd_ndisc_router_route_get_prefixlen(rt, &prefixlen);
 286         if (r < 0)
 287                 return log_link_warning_errno(link, r, "Failed to get route prefix length: %m");
 288
 289         r = sd_ndisc_router_route_get_preference(rt, &preference);
 290         if (r < 0)
 291                 return log_link_warning_errno(link, r, "Failed to get default router preference from RA: %m");
 292
 293         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 294         if (r < 0)
 295                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 296
 297         r = route_new(&route);
 298         if (r < 0)
 299                 return log_link_error_errno(link, r, "Could not allocate route: %m");
 300
 301         route->family = AF_INET6;
 302         route->table = link->network->ipv6_accept_ra_route_table;
 303         route->protocol = RTPROT_RA;
 304         route->pref = preference;
 305         route->gw.in6 = gateway;
 306         route->dst_prefixlen = prefixlen;
 307         route->lifetime = time_now + lifetime * USEC_PER_SEC;
 308
 309         r = sd_ndisc_router_route_get_address(rt, &route->dst.in6);
 310         if (r < 0)
 311                 return log_link_error_errno(link, r, "Failed to get route address: %m");
 312
 313         r = route_configure(route, link, ndisc_route_handler);
 314         if (r < 0) {
 315                 log_link_warning_errno(link, r, "Could not set additional route: %m");
 316                 link_enter_failed(link);
 317                 return r;
 318         }
 319
 320         link->ndisc_messages++;
 321
 322         return 0;
 323 }
 324
 325 static void ndisc_rdnss_hash_func(const void *p, struct siphash *state) {
 326         const NDiscRDNSS *x = p;
 327
 328         siphash24_compress(&x->address, sizeof(x->address), state);
 329 }
 330
 331 static int ndisc_rdnss_compare_func(const void *_a, const void *_b) {
 332         const NDiscRDNSS *a = _a, *b = _b;
 333
 334         return memcmp(&a->address, &b->address, sizeof(a->address));
 335 }
 336
 337 static const struct hash_ops ndisc_rdnss_hash_ops = {
 338         .hash = ndisc_rdnss_hash_func,
 339         .compare = ndisc_rdnss_compare_func
 340 };
 341
 342 static int ndisc_router_process_rdnss(Link *link, sd_ndisc_router *rt) {
 343         uint32_t lifetime;
 344         const struct in6_addr *a;
 345         usec_t time_now;
 346         int i, n, r;
 347
 348         assert(link);
 349         assert(rt);
 350
 351         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 352         if (r < 0)
 353                 return log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 354
 355         r = sd_ndisc_router_rdnss_get_lifetime(rt, &lifetime);
 356         if (r < 0)
 357                 return log_link_warning_errno(link, r, "Failed to get RDNSS lifetime: %m");
 358
 359         n = sd_ndisc_router_rdnss_get_addresses(rt, &a);
 360         if (n < 0)
 361                 return log_link_warning_errno(link, n, "Failed to get RDNSS addresses: %m");
 362
 363         for (i = 0; i < n; i++) {
 364                 _cleanup_free_ NDiscRDNSS *x = NULL;
 365                 NDiscRDNSS d = {
 366                         .address = a[i],
 367                 }, *y;
 368
 369                 if (lifetime == 0) {
 370                         (void) set_remove(link->ndisc_rdnss, &d);
 371                         link_dirty(link);
 372                         continue;
 373                 }
 374
 375                 y = set_get(link->ndisc_rdnss, &d);
 376                 if (y) {
 377                         y->valid_until = time_now + lifetime * USEC_PER_SEC;
 378                         continue;
 379                 }
 380
 381                 ndisc_vacuum(link);
 382
 383                 if (set_size(link->ndisc_rdnss) >= NDISC_RDNSS_MAX) {
 384                         log_link_warning(link, "Too many RDNSS records per link, ignoring.");
 385                         continue;
 386                 }
 387
 388                 r = set_ensure_allocated(&link->ndisc_rdnss, &ndisc_rdnss_hash_ops);
 389                 if (r < 0)
 390                         return log_oom();
 391
 392                 x = new(NDiscRDNSS, 1);
 393                 if (!x)
 394                         return log_oom();
 395
 396                 *x = (NDiscRDNSS) {
 397                         .address = a[i],
 398                         .valid_until = time_now + lifetime * USEC_PER_SEC,
 399                 };
 400
 401                 r = set_put(link->ndisc_rdnss, x);
 402                 if (r < 0)
 403                         return log_oom();
 404
 405                 TAKE_PTR(x);
 406
 407                 assert(r > 0);
 408                 link_dirty(link);
 409         }
 410
 411         return 0;
 412 }
 413
 414 static void ndisc_dnssl_hash_func(const void *p, struct siphash *state) {
 415         const NDiscDNSSL *x = p;
 416
 417         siphash24_compress(NDISC_DNSSL_DOMAIN(x), strlen(NDISC_DNSSL_DOMAIN(x)), state);
 418 }
 419
 420 static int ndisc_dnssl_compare_func(const void *_a, const void *_b) {
 421         const NDiscDNSSL *a = _a, *b = _b;
 422
 423         return strcmp(NDISC_DNSSL_DOMAIN(a), NDISC_DNSSL_DOMAIN(b));
 424 }
 425
 426 static const struct hash_ops ndisc_dnssl_hash_ops = {
 427         .hash = ndisc_dnssl_hash_func,
 428         .compare = ndisc_dnssl_compare_func
 429 };
 430
 431 static void ndisc_router_process_dnssl(Link *link, sd_ndisc_router *rt) {
 432         _cleanup_strv_free_ char **l = NULL;
 433         uint32_t lifetime;
 434         usec_t time_now;
 435         char **i;
 436         int r;
 437
 438         assert(link);
 439         assert(rt);
 440
 441         r = sd_ndisc_router_get_timestamp(rt, clock_boottime_or_monotonic(), &time_now);
 442         if (r < 0) {
 443                 log_link_warning_errno(link, r, "Failed to get RA timestamp: %m");
 444                 return;
 445         }
 446
 447         r = sd_ndisc_router_dnssl_get_lifetime(rt, &lifetime);
 448         if (r < 0) {
 449                 log_link_warning_errno(link, r, "Failed to get RDNSS lifetime: %m");
 450                 return;
 451         }
 452
 453         r = sd_ndisc_router_dnssl_get_domains(rt, &l);
 454         if (r < 0) {
 455                 log_link_warning_errno(link, r, "Failed to get RDNSS addresses: %m");
 456                 return;
 457         }
 458
 459         STRV_FOREACH(i, l) {
 460                 _cleanup_free_ NDiscDNSSL *s;
 461                 NDiscDNSSL *x;
 462
 463                 s = malloc0(ALIGN(sizeof(NDiscDNSSL)) + strlen(*i) + 1);
 464                 if (!s) {
 465                         log_oom();
 466                         return;
 467                 }
 468
 469                 strcpy(NDISC_DNSSL_DOMAIN(s), *i);
 470
 471                 if (lifetime == 0) {
 472                         (void) set_remove(link->ndisc_dnssl, s);
 473                         link_dirty(link);
 474                         continue;
 475                 }
 476
 477                 x = set_get(link->ndisc_dnssl, s);
 478                 if (x) {
 479                         x->valid_until = time_now + lifetime * USEC_PER_SEC;
 480                         continue;
 481                 }
 482
 483                 ndisc_vacuum(link);
 484
 485                 if (set_size(link->ndisc_dnssl) >= NDISC_DNSSL_MAX) {
 486                         log_link_warning(link, "Too many DNSSL records per link, ignoring.");
 487                         continue;
 488                 }
 489
 490                 r = set_ensure_allocated(&link->ndisc_dnssl, &ndisc_dnssl_hash_ops);
 491                 if (r < 0) {
 492                         log_oom();
 493                         return;
 494                 }
 495
 496                 s->valid_until = time_now + lifetime * USEC_PER_SEC;
 497
 498                 r = set_put(link->ndisc_dnssl, s);
 499                 if (r < 0) {
 500                         log_oom();
 501                         return;
 502                 }
 503
 504                 s = NULL;
 505                 assert(r > 0);
 506                 link_dirty(link);
 507         }
 508 }
 509
 510 static void ndisc_router_process_options(Link *link, sd_ndisc_router *rt) {
 511         int r;
 512
 513         assert(link);
 514         assert(rt);
 515
 516         r = sd_ndisc_router_option_rewind(rt);
 517         for (;;) {
 518                 uint8_t type;
 519
 520                 if (r < 0) {
 521                         log_link_warning_errno(link, r, "Failed to iterate through options: %m");
 522                         return;
 523                 }
 524                 if (r == 0) /* EOF */
 525                         break;
 526
 527                 r = sd_ndisc_router_option_get_type(rt, &type);
 528                 if (r < 0) {
 529                         log_link_warning_errno(link, r, "Failed to get RA option type: %m");
 530                         return;
 531                 }
 532
 533                 switch (type) {
 534
 535                 case SD_NDISC_OPTION_PREFIX_INFORMATION: {
 536                         uint8_t flags;
 537
 538                         r = sd_ndisc_router_prefix_get_flags(rt, &flags);
 539                         if (r < 0) {
 540                                 log_link_warning_errno(link, r, "Failed to get RA prefix flags: %m");
 541                                 return;
 542                         }
 543
 544                         if (flags & ND_OPT_PI_FLAG_ONLINK)
 545                                 (void) ndisc_router_process_onlink_prefix(link, rt);
 546                         if (flags & ND_OPT_PI_FLAG_AUTO)
 547                                 (void) ndisc_router_process_autonomous_prefix(link, rt);
 548
 549                         break;
 550                 }
 551
 552                 case SD_NDISC_OPTION_ROUTE_INFORMATION:
 553                         (void) ndisc_router_process_route(link, rt);
 554                         break;
 555
 556                 case SD_NDISC_OPTION_RDNSS:
 557                         if (link->network->ipv6_accept_ra_use_dns)
 558                                 (void) ndisc_router_process_rdnss(link, rt);
 559                         break;
 560
 561                 case SD_NDISC_OPTION_DNSSL:
 562                         if (link->network->ipv6_accept_ra_use_dns)
 563                                 (void) ndisc_router_process_dnssl(link, rt);
 564                         break;
 565                 }
 566
 567                 r = sd_ndisc_router_option_next(rt);
 568         }
 569 }
 570
 571 static int ndisc_router_handler(Link *link, sd_ndisc_router *rt) {
 572         uint64_t flags;
 573         int r = 0;
 574
 575         assert(link);
 576         assert(link->network);
 577         assert(link->manager);
 578         assert(rt);
 579
 580         r = sd_ndisc_router_get_flags(rt, &flags);
 581         if (r < 0)
 582                 return log_link_warning_errno(link, r, "Failed to get RA flags: %m");
 583
 584         if (flags & (ND_RA_FLAG_MANAGED | ND_RA_FLAG_OTHER)) {
 585                 /* (re)start DHCPv6 client in stateful or stateless mode according to RA flags */
 586                 r = dhcp6_request_address(link, !(flags & ND_RA_FLAG_MANAGED));
 587                 if (r < 0 && r != -EBUSY)
 588                         log_link_warning_errno(link, r, "Could not acquire DHCPv6 lease on NDisc request: %m");
 589                 else {
 590                         log_link_debug(link, "Acquiring DHCPv6 lease on NDisc request");
 591                         r = 0;
 592                 }
 593         }
 594
 595         ndisc_router_process_default(link, rt);
 596         ndisc_router_process_options(link, rt);
 597
 598         return r;
 599 }
 600
 601 static void ndisc_handler(sd_ndisc *nd, sd_ndisc_event event, sd_ndisc_router *rt, void *userdata) {
 602         Link *link = userdata;
 603
 604         assert(link);
 605
 606         if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
 607                 return;
 608
 609         switch (event) {
 610
 611         case SD_NDISC_EVENT_ROUTER:
 612                 (void) ndisc_router_handler(link, rt);
 613                 break;
 614
 615         case SD_NDISC_EVENT_TIMEOUT:
 616                 link->ndisc_configured = true;
 617                 link_check_ready(link);
 618
 619                 break;
 620         default:
 621                 log_link_warning(link, "IPv6 Neighbor Discovery unknown event: %d", event);
 622         }
 623 }
 624
 625 int ndisc_configure(Link *link) {
 626         int r;
 627
 628         assert(link);
 629
 630         r = sd_ndisc_new(&link->ndisc);
 631         if (r < 0)
 632                 return r;
 633
 634         r = sd_ndisc_attach_event(link->ndisc, NULL, 0);
 635         if (r < 0)
 636                 return r;
 637
 638         r = sd_ndisc_set_mac(link->ndisc, &link->mac);
 639         if (r < 0)
 640                 return r;
 641
 642         r = sd_ndisc_set_ifindex(link->ndisc, link->ifindex);
 643         if (r < 0)
 644                 return r;
 645
 646         r = sd_ndisc_set_callback(link->ndisc, ndisc_handler, link);
 647         if (r < 0)
 648                 return r;
 649
 650         return 0;
 651 }
 652
 653 void ndisc_vacuum(Link *link) {
 654         NDiscRDNSS *r;
 655         NDiscDNSSL *d;
 656         Iterator i;
 657         usec_t time_now;
 658
 659         assert(link);
 660
 661         /* Removes all RDNSS and DNSSL entries whose validity time has passed */
 662
 663         time_now = now(clock_boottime_or_monotonic());
 664
 665         SET_FOREACH(r, link->ndisc_rdnss, i)
 666                 if (r->valid_until < time_now) {
 667                         free(set_remove(link->ndisc_rdnss, r));
 668                         link_dirty(link);
 669                 }
 670
 671         SET_FOREACH(d, link->ndisc_dnssl, i)
 672                 if (d->valid_until < time_now) {
 673                         free(set_remove(link->ndisc_dnssl, d));
 674                         link_dirty(link);
 675                 }
 676 }
 677
 678 void ndisc_flush(Link *link) {
 679         assert(link);
 680
 681         /* Removes all RDNSS and DNSSL entries, without exception */
 682
 683         link->ndisc_rdnss = set_free_free(link->ndisc_rdnss);
 684         link->ndisc_dnssl = set_free_free(link->ndisc_dnssl);
 685 }