src/libsystemd-network/sd-radv.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright © 2017 Intel Corporation. All rights reserved.
   4 ***/
   5
   6 #include <netinet/icmp6.h>
   7 #include <netinet/in.h>
   8 #include <arpa/inet.h>
   9
  10 #include "sd-radv.h"
  11
  12 #include "alloc-util.h"
  13 #include "dns-domain.h"
  14 #include "ether-addr-util.h"
  15 #include "event-util.h"
  16 #include "fd-util.h"
  17 #include "icmp6-util.h"
  18 #include "in-addr-util.h"
  19 #include "io-util.h"
  20 #include "macro.h"
  21 #include "radv-internal.h"
  22 #include "random-util.h"
  23 #include "socket-util.h"
  24 #include "string-util.h"
  25 #include "strv.h"
  26 #include "util.h"
  27
  28 _public_ int sd_radv_new(sd_radv **ret) {
  29         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  30
  31         assert_return(ret, -EINVAL);
  32
  33         ra = new(sd_radv, 1);
  34         if (!ra)
  35                 return -ENOMEM;
  36
  37         *ra = (sd_radv) {
  38                 .n_ref = 1,
  39                 .fd = -1,
  40         };
  41
  42         *ret = TAKE_PTR(ra);
  43
  44         return 0;
  45 }
  46
  47 _public_ int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  48         int r;
  49
  50         assert_return(ra, -EINVAL);
  51         assert_return(!ra->event, -EBUSY);
  52
  53         if (event)
  54                 ra->event = sd_event_ref(event);
  55         else {
  56                 r = sd_event_default(&ra->event);
  57                 if (r < 0)
  58                         return 0;
  59         }
  60
  61         ra->event_priority = priority;
  62
  63         return 0;
  64 }
  65
  66 _public_ int sd_radv_detach_event(sd_radv *ra) {
  67
  68         assert_return(ra, -EINVAL);
  69
  70         ra->event = sd_event_unref(ra->event);
  71         return 0;
  72 }
  73
  74 _public_ sd_event *sd_radv_get_event(sd_radv *ra) {
  75         assert_return(ra, NULL);
  76
  77         return ra->event;
  78 }
  79
  80 static void radv_reset(sd_radv *ra) {
  81         assert(ra);
  82
  83         (void) event_source_disable(ra->timeout_event_source);
  84
  85         ra->recv_event_source =
  86                 sd_event_source_unref(ra->recv_event_source);
  87
  88         ra->ra_sent = 0;
  89 }
  90
  91 static sd_radv *radv_free(sd_radv *ra) {
  92         if (!ra)
  93                 return NULL;
  94
  95         while (ra->prefixes) {
  96                 sd_radv_prefix *p = ra->prefixes;
  97
  98                 LIST_REMOVE(prefix, ra->prefixes, p);
  99                 sd_radv_prefix_unref(p);
 100         }
 101
 102         free(ra->rdnss);
 103         free(ra->dnssl);
 104
 105         ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source);
 106
 107         radv_reset(ra);
 108
 109         sd_radv_detach_event(ra);
 110
 111         ra->fd = safe_close(ra->fd);
 112
 113         return mfree(ra);
 114 }
 115
 116 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
 117
 118 static int radv_send(sd_radv *ra, const struct in6_addr *dst, uint32_t router_lifetime) {
 119         sd_radv_prefix *p;
 120         struct sockaddr_in6 dst_addr = {
 121                 .sin6_family = AF_INET6,
 122                 .sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
 123         };
 124         struct nd_router_advert adv = {};
 125         struct {
 126                 struct nd_opt_hdr opthdr;
 127                 struct ether_addr slladdr;
 128         } _packed_ opt_mac = {
 129                 .opthdr = {
 130                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 131                         .nd_opt_len = (sizeof(struct nd_opt_hdr) +
 132                                        sizeof(struct ether_addr) - 1) /8 + 1,
 133                 },
 134         };
 135         struct nd_opt_mtu opt_mtu =  {
 136                 .nd_opt_mtu_type = ND_OPT_MTU,
 137                 .nd_opt_mtu_len = 1,
 138         };
 139         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, RDNSS
 140            and DNSSL */
 141         struct iovec iov[5 + ra->n_prefixes];
 142         struct msghdr msg = {
 143                 .msg_name = &dst_addr,
 144                 .msg_namelen = sizeof(dst_addr),
 145                 .msg_iov = iov,
 146         };
 147         usec_t time_now;
 148         int r;
 149
 150         assert(ra);
 151
 152         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 153         if (r < 0)
 154                 return r;
 155
 156         if (dst && !IN6_IS_ADDR_UNSPECIFIED(dst))
 157                 dst_addr.sin6_addr = *dst;
 158
 159         adv.nd_ra_type = ND_ROUTER_ADVERT;
 160         adv.nd_ra_curhoplimit = ra->hop_limit;
 161         adv.nd_ra_flags_reserved = ra->flags;
 162         adv.nd_ra_router_lifetime = htobe16(router_lifetime);
 163         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 164
 165         /* MAC address is optional, either because the link does not use L2
 166            addresses or load sharing is desired. See RFC 4861, Section 4.2 */
 167         if (!ether_addr_is_null(&ra->mac_addr)) {
 168                 opt_mac.slladdr = ra->mac_addr;
 169                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 170         }
 171
 172         if (ra->mtu) {
 173                 opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
 174                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 175         }
 176
 177         LIST_FOREACH(prefix, p, ra->prefixes) {
 178                 if (p->valid_until) {
 179
 180                         if (time_now > p->valid_until)
 181                                 p->opt.valid_lifetime = 0;
 182                         else
 183                                 p->opt.valid_lifetime = htobe32((p->valid_until - time_now) / USEC_PER_SEC);
 184
 185                         if (time_now > p->preferred_until)
 186                                 p->opt.preferred_lifetime = 0;
 187                         else
 188                                 p->opt.preferred_lifetime = htobe32((p->preferred_until - time_now) / USEC_PER_SEC);
 189                 }
 190                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 191         }
 192
 193         if (ra->rdnss)
 194                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 195
 196         if (ra->dnssl)
 197                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 198
 199         if (sendmsg(ra->fd, &msg, 0) < 0)
 200                 return -errno;
 201
 202         return 0;
 203 }
 204
 205 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 206         sd_radv *ra = userdata;
 207         _cleanup_free_ char *addr = NULL;
 208         struct in6_addr src;
 209         triple_timestamp timestamp;
 210         int r;
 211         ssize_t buflen;
 212         _cleanup_free_ char *buf = NULL;
 213
 214         assert(s);
 215         assert(ra);
 216         assert(ra->event);
 217
 218         buflen = next_datagram_size_fd(fd);
 219         if (buflen < 0)
 220                 return (int) buflen;
 221
 222         buf = new0(char, buflen);
 223         if (!buf)
 224                 return -ENOMEM;
 225
 226         r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
 227         if (r < 0) {
 228                 switch (r) {
 229                 case -EADDRNOTAVAIL:
 230                         (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
 231                         log_radv("Received RS from non-link-local address %s. Ignoring", addr);
 232                         break;
 233
 234                 case -EMULTIHOP:
 235                         log_radv("Received RS with invalid hop limit. Ignoring.");
 236                         break;
 237
 238                 case -EPFNOSUPPORT:
 239                         log_radv("Received invalid source address from ICMPv6 socket. Ignoring.");
 240                         break;
 241
 242                 case -EAGAIN: /* ignore spurious wakeups */
 243                         break;
 244
 245                 default:
 246                         log_radv_errno(r, "Unexpected error receiving from ICMPv6 socket: %m");
 247                         break;
 248                 }
 249
 250                 return 0;
 251         }
 252
 253         if ((size_t) buflen < sizeof(struct nd_router_solicit)) {
 254                 log_radv("Too short packet received");
 255                 return 0;
 256         }
 257
 258         (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr);
 259
 260         r = radv_send(ra, &src, ra->lifetime);
 261         if (r < 0)
 262                 log_radv_errno(r, "Unable to send solicited Router Advertisement to %s: %m", strnull(addr));
 263         else
 264                 log_radv("Sent solicited Router Advertisement to %s", strnull(addr));
 265
 266         return 0;
 267 }
 268
 269 static usec_t radv_compute_timeout(usec_t min, usec_t max) {
 270         assert_return(min <= max, SD_RADV_DEFAULT_MIN_TIMEOUT_USEC);
 271
 272         return min + (random_u32() % (max - min));
 273 }
 274
 275 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 276         int r;
 277         sd_radv *ra = userdata;
 278         usec_t min_timeout = SD_RADV_DEFAULT_MIN_TIMEOUT_USEC;
 279         usec_t max_timeout = SD_RADV_DEFAULT_MAX_TIMEOUT_USEC;
 280         usec_t time_now, timeout;
 281         char time_string[FORMAT_TIMESPAN_MAX];
 282
 283         assert(s);
 284         assert(ra);
 285         assert(ra->event);
 286
 287         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 288         if (r < 0)
 289                 goto fail;
 290
 291         r = radv_send(ra, NULL, ra->lifetime);
 292         if (r < 0)
 293                 log_radv_errno(r, "Unable to send Router Advertisement: %m");
 294
 295         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 296         if (ra->ra_sent < SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS) {
 297                 max_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 298                 min_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC / 3;
 299         }
 300
 301         timeout = radv_compute_timeout(min_timeout, max_timeout);
 302
 303         log_radv("Next Router Advertisement in %s",
 304                  format_timespan(time_string, FORMAT_TIMESPAN_MAX,
 305                                  timeout, USEC_PER_SEC));
 306
 307         r = event_reset_time(ra->event, &ra->timeout_event_source,
 308                              clock_boottime_or_monotonic(),
 309                              time_now + timeout, MSEC_PER_SEC,
 310                              radv_timeout, ra,
 311                              ra->event_priority, "radv-timeout", true);
 312         if (r < 0)
 313                 goto fail;
 314
 315         ra->ra_sent++;
 316
 317         return 0;
 318
 319 fail:
 320         sd_radv_stop(ra);
 321
 322         return 0;
 323 }
 324
 325 _public_ int sd_radv_stop(sd_radv *ra) {
 326         int r;
 327
 328         assert_return(ra, -EINVAL);
 329
 330         if (ra->state == SD_RADV_STATE_IDLE)
 331                 return 0;
 332
 333         log_radv("Stopping IPv6 Router Advertisement daemon");
 334
 335         /* RFC 4861, Section 6.2.5, send at least one Router Advertisement
 336            with zero lifetime  */
 337         r = radv_send(ra, NULL, 0);
 338         if (r < 0)
 339                 log_radv_errno(r, "Unable to send last Router Advertisement with router lifetime set to zero: %m");
 340
 341         radv_reset(ra);
 342         ra->fd = safe_close(ra->fd);
 343         ra->state = SD_RADV_STATE_IDLE;
 344
 345         return 0;
 346 }
 347
 348 _public_ int sd_radv_start(sd_radv *ra) {
 349         int r;
 350
 351         assert_return(ra, -EINVAL);
 352         assert_return(ra->event, -EINVAL);
 353         assert_return(ra->ifindex > 0, -EINVAL);
 354
 355         if (ra->state != SD_RADV_STATE_IDLE)
 356                 return 0;
 357
 358         r = event_reset_time(ra->event, &ra->timeout_event_source,
 359                              clock_boottime_or_monotonic(),
 360                              0, 0,
 361                              radv_timeout, ra,
 362                              ra->event_priority, "radv-timeout", true);
 363         if (r < 0)
 364                 goto fail;
 365
 366         r = icmp6_bind_router_advertisement(ra->ifindex);
 367         if (r < 0)
 368                 goto fail;
 369
 370         ra->fd = r;
 371
 372         r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra);
 373         if (r < 0)
 374                 goto fail;
 375
 376         r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority);
 377         if (r < 0)
 378                 goto fail;
 379
 380         (void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message");
 381
 382         ra->state = SD_RADV_STATE_ADVERTISING;
 383
 384         log_radv("Started IPv6 Router Advertisement daemon");
 385
 386         return 0;
 387
 388  fail:
 389         radv_reset(ra);
 390
 391         return r;
 392 }
 393
 394 _public_ int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 395         assert_return(ra, -EINVAL);
 396         assert_return(ifindex >= -1, -EINVAL);
 397
 398         if (ra->state != SD_RADV_STATE_IDLE)
 399                 return -EBUSY;
 400
 401         ra->ifindex = ifindex;
 402
 403         return 0;
 404 }
 405
 406 _public_ int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 407         assert_return(ra, -EINVAL);
 408
 409         if (ra->state != SD_RADV_STATE_IDLE)
 410                 return -EBUSY;
 411
 412         if (mac_addr)
 413                 ra->mac_addr = *mac_addr;
 414         else
 415                 zero(ra->mac_addr);
 416
 417         return 0;
 418 }
 419
 420 _public_ int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 421         assert_return(ra, -EINVAL);
 422         assert_return(mtu >= 1280, -EINVAL);
 423
 424         ra->mtu = mtu;
 425
 426         return 0;
 427 }
 428
 429 _public_ int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 430         assert_return(ra, -EINVAL);
 431
 432         if (ra->state != SD_RADV_STATE_IDLE)
 433                 return -EBUSY;
 434
 435         ra->hop_limit = hop_limit;
 436
 437         return 0;
 438 }
 439
 440 _public_ int sd_radv_set_router_lifetime(sd_radv *ra, uint32_t router_lifetime) {
 441         assert_return(ra, -EINVAL);
 442
 443         if (ra->state != SD_RADV_STATE_IDLE)
 444                 return -EBUSY;
 445
 446         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the
 447            preference value MUST be set to (00) by the sender..." */
 448         if (router_lifetime == 0 &&
 449             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 450                 return -ETIME;
 451
 452         ra->lifetime = router_lifetime;
 453
 454         return 0;
 455 }
 456
 457 _public_ int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 458         assert_return(ra, -EINVAL);
 459
 460         if (ra->state != SD_RADV_STATE_IDLE)
 461                 return -EBUSY;
 462
 463         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 464
 465         return 0;
 466 }
 467
 468 _public_ int sd_radv_set_other_information(sd_radv *ra, int other) {
 469         assert_return(ra, -EINVAL);
 470
 471         if (ra->state != SD_RADV_STATE_IDLE)
 472                 return -EBUSY;
 473
 474         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 475
 476         return 0;
 477 }
 478
 479 _public_ int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 480         int r = 0;
 481
 482         assert_return(ra, -EINVAL);
 483         assert_return(IN_SET(preference,
 484                              SD_NDISC_PREFERENCE_LOW,
 485                              SD_NDISC_PREFERENCE_MEDIUM,
 486                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 487
 488         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 489
 490         return r;
 491 }
 492
 493 _public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, int dynamic) {
 494         sd_radv_prefix *cur;
 495         int r;
 496         _cleanup_free_ char *addr_p = NULL;
 497         char time_string_preferred[FORMAT_TIMESPAN_MAX];
 498         char time_string_valid[FORMAT_TIMESPAN_MAX];
 499         usec_t time_now, valid, preferred, valid_until, preferred_until;
 500
 501         assert_return(ra, -EINVAL);
 502
 503         if (!p)
 504                 return -EINVAL;
 505
 506         /* Refuse prefixes that don't have a prefix set */
 507         if (IN6_IS_ADDR_UNSPECIFIED(&p->opt.in6_addr))
 508                 return -ENOEXEC;
 509
 510         LIST_FOREACH(prefix, cur, ra->prefixes) {
 511
 512                 r = in_addr_prefix_intersect(AF_INET6,
 513                                              (union in_addr_union*) &cur->opt.in6_addr,
 514                                              cur->opt.prefixlen,
 515                                              (union in_addr_union*) &p->opt.in6_addr,
 516                                              p->opt.prefixlen);
 517                 if (r > 0) {
 518                         _cleanup_free_ char *addr_cur = NULL;
 519
 520                         (void) in_addr_to_string(AF_INET6,
 521                                                  (union in_addr_union*) &p->opt.in6_addr,
 522                                                  &addr_p);
 523
 524                         if (dynamic && cur->opt.prefixlen == p->opt.prefixlen)
 525                                 goto update;
 526
 527                         (void) in_addr_to_string(AF_INET6,
 528                                                  (union in_addr_union*) &cur->opt.in6_addr,
 529                                                  &addr_cur);
 530                         log_radv("IPv6 prefix %s/%u already configured, ignoring %s/%u",
 531                                  addr_cur, cur->opt.prefixlen,
 532                                  addr_p, p->opt.prefixlen);
 533
 534                         return -EEXIST;
 535                 }
 536         }
 537
 538         p = sd_radv_prefix_ref(p);
 539
 540         LIST_APPEND(prefix, ra->prefixes, p);
 541
 542         ra->n_prefixes++;
 543
 544         (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &p->opt.in6_addr, &addr_p);
 545
 546         if (!dynamic) {
 547                 log_radv("Added prefix %s/%d", addr_p, p->opt.prefixlen);
 548                 return 0;
 549         }
 550
 551         cur = p;
 552
 553  update:
 554         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 555         if (r < 0)
 556                 return r;
 557
 558         valid = be32toh(p->opt.valid_lifetime) * USEC_PER_SEC;
 559         valid_until = usec_add(valid, time_now);
 560         if (valid_until == USEC_INFINITY)
 561                 return -EOVERFLOW;
 562
 563         preferred = be32toh(p->opt.preferred_lifetime) * USEC_PER_SEC;
 564         preferred_until = usec_add(preferred, time_now);
 565         if (preferred_until == USEC_INFINITY)
 566                 return -EOVERFLOW;
 567
 568         cur->valid_until = valid_until;
 569         cur->preferred_until = preferred_until;
 570
 571         log_radv("%s prefix %s/%u preferred %s valid %s",
 572                  cur? "Updated": "Added",
 573                  addr_p, p->opt.prefixlen,
 574                  format_timespan(time_string_preferred, FORMAT_TIMESPAN_MAX,
 575                                  preferred, USEC_PER_SEC),
 576                  format_timespan(time_string_valid, FORMAT_TIMESPAN_MAX,
 577                                  valid, USEC_PER_SEC));
 578
 579         return 0;
 580 }
 581
 582 _public_ sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra,
 583                                                const struct in6_addr *prefix,
 584                                                unsigned char prefixlen) {
 585         sd_radv_prefix *cur, *next;
 586
 587         assert_return(ra, NULL);
 588         assert_return(prefix, NULL);
 589
 590         LIST_FOREACH_SAFE(prefix, cur, next, ra->prefixes) {
 591                 if (prefixlen != cur->opt.prefixlen)
 592                         continue;
 593
 594                 if (!in_addr_equal(AF_INET6,
 595                                    (union in_addr_union *)prefix,
 596                                    (union in_addr_union *)&cur->opt.in6_addr))
 597                         continue;
 598
 599                 LIST_REMOVE(prefix, ra->prefixes, cur);
 600                 ra->n_prefixes--;
 601
 602                 break;
 603         }
 604
 605         return cur;
 606 }
 607
 608 _public_ int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime,
 609                                const struct in6_addr *dns, size_t n_dns) {
 610         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 611         size_t len;
 612
 613         assert_return(ra, -EINVAL);
 614         assert_return(n_dns < 128, -EINVAL);
 615
 616         if (!dns || n_dns == 0) {
 617                 ra->rdnss = mfree(ra->rdnss);
 618                 ra->n_rdnss = 0;
 619
 620                 return 0;
 621         }
 622
 623         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 624
 625         opt_rdnss = malloc0(len);
 626         if (!opt_rdnss)
 627                 return -ENOMEM;
 628
 629         opt_rdnss->type = SD_RADV_OPT_RDNSS;
 630         opt_rdnss->length = len / 8;
 631         opt_rdnss->lifetime = htobe32(lifetime);
 632
 633         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 634
 635         free_and_replace(ra->rdnss, opt_rdnss);
 636
 637         ra->n_rdnss = n_dns;
 638
 639         return 0;
 640 }
 641
 642 _public_ int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime,
 643                                char **search_list) {
 644         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 645         size_t len = 0;
 646         char **s;
 647         uint8_t *p;
 648
 649         assert_return(ra, -EINVAL);
 650
 651         if (strv_isempty(search_list)) {
 652                 ra->dnssl = mfree(ra->dnssl);
 653                 return 0;
 654         }
 655
 656         STRV_FOREACH(s, search_list)
 657                 len += strlen(*s) + 2;
 658
 659         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 660
 661         opt_dnssl = malloc0(len);
 662         if (!opt_dnssl)
 663                 return -ENOMEM;
 664
 665         opt_dnssl->type = SD_RADV_OPT_DNSSL;
 666         opt_dnssl->length = len / 8;
 667         opt_dnssl->lifetime = htobe32(lifetime);
 668
 669         p = (uint8_t *)(opt_dnssl + 1);
 670         len -= sizeof(struct sd_radv_opt_dns);
 671
 672         STRV_FOREACH(s, search_list) {
 673                 int r;
 674
 675                 r = dns_name_to_wire_format(*s, p, len, false);
 676                 if (r < 0)
 677                         return r;
 678
 679                 if (len < (size_t)r)
 680                         return -ENOBUFS;
 681
 682                 p += r;
 683                 len -= r;
 684         }
 685
 686         free_and_replace(ra->dnssl, opt_dnssl);
 687
 688         return 0;
 689 }
 690
 691 _public_ int sd_radv_prefix_new(sd_radv_prefix **ret) {
 692         sd_radv_prefix *p;
 693
 694         assert_return(ret, -EINVAL);
 695
 696         p = new(sd_radv_prefix, 1);
 697         if (!p)
 698                 return -ENOMEM;
 699
 700         *p = (sd_radv_prefix) {
 701                 .n_ref = 1,
 702
 703                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 704                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 705                 .opt.prefixlen = 64,
 706
 707                 /* RFC 4861, Section 6.2.1 */
 708                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 709
 710                 .opt.preferred_lifetime = htobe32(604800),
 711                 .opt.valid_lifetime = htobe32(2592000),
 712         };
 713
 714         *ret = p;
 715         return 0;
 716 }
 717
 718 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
 719
 720 _public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr,
 721                                        unsigned char prefixlen) {
 722         assert_return(p, -EINVAL);
 723         assert_return(in6_addr, -EINVAL);
 724
 725         if (prefixlen < 3 || prefixlen > 128)
 726                 return -EINVAL;
 727
 728         if (prefixlen > 64)
 729                 /* unusual but allowed, log it */
 730                 log_radv("Unusual prefix length %d greater than 64", prefixlen);
 731
 732         p->opt.in6_addr = *in6_addr;
 733         p->opt.prefixlen = prefixlen;
 734
 735         return 0;
 736 }
 737
 738 _public_ int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
 739         assert_return(p, -EINVAL);
 740
 741         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
 742
 743         return 0;
 744 }
 745
 746 _public_ int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,
 747                                                           int address_autoconfiguration) {
 748         assert_return(p, -EINVAL);
 749
 750         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
 751
 752         return 0;
 753 }
 754
 755 _public_ int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p,
 756                                                uint32_t valid_lifetime) {
 757         assert_return(p, -EINVAL);
 758
 759         p->opt.valid_lifetime = htobe32(valid_lifetime);
 760
 761         return 0;
 762 }
 763
 764 _public_ int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p,
 765                                                    uint32_t preferred_lifetime) {
 766         assert_return(p, -EINVAL);
 767
 768         p->opt.preferred_lifetime = htobe32(preferred_lifetime);
 769
 770         return 0;
 771 }