src/libsystemd-network/sd-radv.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   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 "memory-util.h"
  22 #include "network-common.h"
  23 #include "radv-internal.h"
  24 #include "random-util.h"
  25 #include "socket-util.h"
  26 #include "string-util.h"
  27 #include "strv.h"
  28
  29 int sd_radv_new(sd_radv **ret) {
  30         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  31
  32         assert_return(ret, -EINVAL);
  33
  34         ra = new(sd_radv, 1);
  35         if (!ra)
  36                 return -ENOMEM;
  37
  38         *ra = (sd_radv) {
  39                 .n_ref = 1,
  40                 .fd = -1,
  41                 .lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
  42         };
  43
  44         *ret = TAKE_PTR(ra);
  45
  46         return 0;
  47 }
  48
  49 int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  50         int r;
  51
  52         assert_return(ra, -EINVAL);
  53         assert_return(!ra->event, -EBUSY);
  54
  55         if (event)
  56                 ra->event = sd_event_ref(event);
  57         else {
  58                 r = sd_event_default(&ra->event);
  59                 if (r < 0)
  60                         return 0;
  61         }
  62
  63         ra->event_priority = priority;
  64
  65         return 0;
  66 }
  67
  68 int sd_radv_detach_event(sd_radv *ra) {
  69
  70         assert_return(ra, -EINVAL);
  71
  72         ra->event = sd_event_unref(ra->event);
  73         return 0;
  74 }
  75
  76 sd_event *sd_radv_get_event(sd_radv *ra) {
  77         assert_return(ra, NULL);
  78
  79         return ra->event;
  80 }
  81
  82 int sd_radv_is_running(sd_radv *ra) {
  83         assert_return(ra, false);
  84
  85         return ra->state != RADV_STATE_IDLE;
  86 }
  87
  88 static void radv_reset(sd_radv *ra) {
  89         assert(ra);
  90
  91         (void) event_source_disable(ra->timeout_event_source);
  92
  93         ra->recv_event_source = sd_event_source_disable_unref(ra->recv_event_source);
  94
  95         ra->ra_sent = 0;
  96 }
  97
  98 static sd_radv *radv_free(sd_radv *ra) {
  99         if (!ra)
 100                 return NULL;
 101
 102         while (ra->prefixes) {
 103                 sd_radv_prefix *p = ra->prefixes;
 104
 105                 LIST_REMOVE(prefix, ra->prefixes, p);
 106                 sd_radv_prefix_unref(p);
 107         }
 108
 109         while (ra->route_prefixes) {
 110                 sd_radv_route_prefix *p = ra->route_prefixes;
 111
 112                 LIST_REMOVE(prefix, ra->route_prefixes, p);
 113                 sd_radv_route_prefix_unref(p);
 114         }
 115
 116         free(ra->rdnss);
 117         free(ra->dnssl);
 118
 119         radv_reset(ra);
 120
 121         sd_event_source_unref(ra->timeout_event_source);
 122         sd_radv_detach_event(ra);
 123
 124         ra->fd = safe_close(ra->fd);
 125         free(ra->ifname);
 126
 127         return mfree(ra);
 128 }
 129
 130 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
 131
 132 static bool router_lifetime_is_valid(usec_t lifetime_usec) {
 133         return lifetime_usec == 0 ||
 134                 (lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
 135                  lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
 136 }
 137
 138 static be32_t usec_to_be32_sec(usec_t usec) {
 139         if (usec == USEC_INFINITY)
 140                 /* UINT32_MAX is handled as infinity. */
 141                 return htobe32(UINT32_MAX);
 142
 143         if (usec >= UINT32_MAX * USEC_PER_SEC)
 144                 /* Finite but too large. Let's use the largest finite value. */
 145                 return htobe32(UINT32_MAX - 1);
 146
 147         return htobe32(usec / USEC_PER_SEC);
 148 }
 149
 150 static int radv_send(sd_radv *ra, const struct in6_addr *dst, usec_t lifetime_usec) {
 151         sd_radv_route_prefix *rt;
 152         sd_radv_prefix *p;
 153         struct sockaddr_in6 dst_addr = {
 154                 .sin6_family = AF_INET6,
 155                 .sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
 156         };
 157         struct nd_router_advert adv = {};
 158         struct {
 159                 struct nd_opt_hdr opthdr;
 160                 struct ether_addr slladdr;
 161         } _packed_ opt_mac = {
 162                 .opthdr = {
 163                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 164                         .nd_opt_len = (sizeof(struct nd_opt_hdr) +
 165                                        sizeof(struct ether_addr) - 1) /8 + 1,
 166                 },
 167         };
 168         struct nd_opt_mtu opt_mtu =  {
 169                 .nd_opt_mtu_type = ND_OPT_MTU,
 170                 .nd_opt_mtu_len = 1,
 171         };
 172         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, RDNSS
 173            and DNSSL */
 174         struct iovec iov[5 + ra->n_prefixes + ra->n_route_prefixes];
 175         struct msghdr msg = {
 176                 .msg_name = &dst_addr,
 177                 .msg_namelen = sizeof(dst_addr),
 178                 .msg_iov = iov,
 179         };
 180         usec_t time_now;
 181         int r;
 182
 183         assert(ra);
 184         assert(router_lifetime_is_valid(lifetime_usec));
 185
 186         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 187         if (r < 0)
 188                 return r;
 189
 190         if (dst && in6_addr_is_set(dst))
 191                 dst_addr.sin6_addr = *dst;
 192
 193         adv.nd_ra_type = ND_ROUTER_ADVERT;
 194         adv.nd_ra_curhoplimit = ra->hop_limit;
 195         adv.nd_ra_flags_reserved = ra->flags;
 196         assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
 197         adv.nd_ra_router_lifetime = htobe16(DIV_ROUND_UP(lifetime_usec, USEC_PER_SEC));
 198         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 199
 200         /* MAC address is optional, either because the link does not use L2
 201            addresses or load sharing is desired. See RFC 4861, Section 4.2 */
 202         if (!ether_addr_is_null(&ra->mac_addr)) {
 203                 opt_mac.slladdr = ra->mac_addr;
 204                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 205         }
 206
 207         if (ra->mtu > 0) {
 208                 opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
 209                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 210         }
 211
 212         LIST_FOREACH(prefix, p, ra->prefixes) {
 213                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 214
 215                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 216                                           p->lifetime_valid_usec);
 217
 218                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 219                                                p->lifetime_preferred_usec,
 220                                                lifetime_valid_usec);
 221
 222                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 223                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 224
 225                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 226         }
 227
 228         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 229                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 230                                                         rt->lifetime_usec));
 231
 232                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 233         }
 234
 235         if (ra->rdnss)
 236                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 237
 238         if (ra->dnssl)
 239                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 240
 241         if (sendmsg(ra->fd, &msg, 0) < 0)
 242                 return -errno;
 243
 244         return 0;
 245 }
 246
 247 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 248         sd_radv *ra = userdata;
 249         _cleanup_free_ char *addr = NULL;
 250         struct in6_addr src;
 251         triple_timestamp timestamp;
 252         int r;
 253         ssize_t buflen;
 254         _cleanup_free_ char *buf = NULL;
 255
 256         assert(s);
 257         assert(ra);
 258         assert(ra->event);
 259
 260         buflen = next_datagram_size_fd(fd);
 261         if (buflen < 0) {
 262                 if (ERRNO_IS_TRANSIENT(buflen) || ERRNO_IS_DISCONNECT(buflen))
 263                         return 0;
 264
 265                 log_radv_errno(ra, buflen, "Failed to determine datagram size to read, ignoring: %m");
 266                 return 0;
 267         }
 268
 269         buf = new0(char, buflen);
 270         if (!buf)
 271                 return -ENOMEM;
 272
 273         r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
 274         if (r < 0) {
 275                 if (ERRNO_IS_TRANSIENT(r) || ERRNO_IS_DISCONNECT(r))
 276                         return 0;
 277
 278                 switch (r) {
 279                 case -EADDRNOTAVAIL:
 280                         (void) in_addr_to_string(AF_INET6, (const union in_addr_union*) &src, &addr);
 281                         log_radv(ra, "Received RS from non-link-local address %s. Ignoring", addr);
 282                         break;
 283
 284                 case -EMULTIHOP:
 285                         log_radv(ra, "Received RS with invalid hop limit. Ignoring.");
 286                         break;
 287
 288                 case -EPFNOSUPPORT:
 289                         log_radv(ra, "Received invalid source address from ICMPv6 socket. Ignoring.");
 290                         break;
 291
 292                 default:
 293                         log_radv_errno(ra, r, "Unexpected error receiving from ICMPv6 socket, ignoring: %m");
 294                         break;
 295                 }
 296
 297                 return 0;
 298         }
 299
 300         if ((size_t) buflen < sizeof(struct nd_router_solicit)) {
 301                 log_radv(ra, "Too short packet received, ignoring");
 302                 return 0;
 303         }
 304
 305         (void) in_addr_to_string(AF_INET6, (const union in_addr_union*) &src, &addr);
 306
 307         r = radv_send(ra, &src, ra->lifetime_usec);
 308         if (r < 0)
 309                 log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", strnull(addr));
 310         else
 311                 log_radv(ra, "Sent solicited Router Advertisement to %s", strnull(addr));
 312
 313         return 0;
 314 }
 315
 316 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 317         usec_t min_timeout, max_timeout, time_now, timeout;
 318         sd_radv *ra = userdata;
 319         int r;
 320
 321         assert(s);
 322         assert(ra);
 323         assert(ra->event);
 324         assert(router_lifetime_is_valid(ra->lifetime_usec));
 325
 326         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 327         if (r < 0)
 328                 goto fail;
 329
 330         r = radv_send(ra, NULL, ra->lifetime_usec);
 331         if (r < 0)
 332                 log_radv_errno(ra, r, "Unable to send Router Advertisement: %m");
 333
 334         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 335         if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 336                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 337         else
 338                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 339
 340         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 341          * so lower the interval here */
 342         if (ra->lifetime_usec > 0)
 343                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 344
 345         if (max_timeout >= 9 * USEC_PER_SEC)
 346                 min_timeout = max_timeout / 3;
 347         else
 348                 min_timeout = max_timeout * 3 / 4;
 349
 350         /* RFC 4861, Section 6.2.1.
 351          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 352          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 353         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 354         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 355         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 356         assert(min_timeout <= max_timeout * 3 / 4);
 357
 358         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 359         log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 360
 361         r = event_reset_time(ra->event, &ra->timeout_event_source,
 362                              clock_boottime_or_monotonic(),
 363                              usec_add(time_now, timeout), MSEC_PER_SEC,
 364                              radv_timeout, ra,
 365                              ra->event_priority, "radv-timeout", true);
 366         if (r < 0)
 367                 goto fail;
 368
 369         ra->ra_sent++;
 370
 371         return 0;
 372
 373 fail:
 374         sd_radv_stop(ra);
 375
 376         return 0;
 377 }
 378
 379 int sd_radv_stop(sd_radv *ra) {
 380         int r;
 381
 382         if (!ra)
 383                 return 0;
 384
 385         if (ra->state == RADV_STATE_IDLE)
 386                 return 0;
 387
 388         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 389
 390         /* RFC 4861, Section 6.2.5, send at least one Router Advertisement
 391            with zero lifetime  */
 392         r = radv_send(ra, NULL, 0);
 393         if (r < 0)
 394                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero: %m");
 395
 396         radv_reset(ra);
 397         ra->fd = safe_close(ra->fd);
 398         ra->state = RADV_STATE_IDLE;
 399
 400         return 0;
 401 }
 402
 403 int sd_radv_start(sd_radv *ra) {
 404         int r;
 405
 406         assert_return(ra, -EINVAL);
 407         assert_return(ra->event, -EINVAL);
 408         assert_return(ra->ifindex > 0, -EINVAL);
 409
 410         if (ra->state != RADV_STATE_IDLE)
 411                 return 0;
 412
 413         r = event_reset_time(ra->event, &ra->timeout_event_source,
 414                              clock_boottime_or_monotonic(),
 415                              0, 0,
 416                              radv_timeout, ra,
 417                              ra->event_priority, "radv-timeout", true);
 418         if (r < 0)
 419                 goto fail;
 420
 421         r = icmp6_bind_router_advertisement(ra->ifindex);
 422         if (r < 0)
 423                 goto fail;
 424
 425         ra->fd = r;
 426
 427         r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra);
 428         if (r < 0)
 429                 goto fail;
 430
 431         r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority);
 432         if (r < 0)
 433                 goto fail;
 434
 435         (void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message");
 436
 437         ra->state = RADV_STATE_ADVERTISING;
 438
 439         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 440
 441         return 0;
 442
 443  fail:
 444         radv_reset(ra);
 445
 446         return r;
 447 }
 448
 449 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 450         assert_return(ra, -EINVAL);
 451         assert_return(ifindex > 0, -EINVAL);
 452
 453         if (ra->state != RADV_STATE_IDLE)
 454                 return -EBUSY;
 455
 456         ra->ifindex = ifindex;
 457
 458         return 0;
 459 }
 460
 461 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 462         assert_return(ra, -EINVAL);
 463         assert_return(ifname, -EINVAL);
 464
 465         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 466                 return -EINVAL;
 467
 468         return free_and_strdup(&ra->ifname, ifname);
 469 }
 470
 471 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 472         int r;
 473
 474         assert_return(ra, -EINVAL);
 475
 476         r = get_ifname(ra->ifindex, &ra->ifname);
 477         if (r < 0)
 478                 return r;
 479
 480         if (ret)
 481                 *ret = ra->ifname;
 482
 483         return 0;
 484 }
 485
 486 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 487         assert_return(ra, -EINVAL);
 488
 489         if (ra->state != RADV_STATE_IDLE)
 490                 return -EBUSY;
 491
 492         if (mac_addr)
 493                 ra->mac_addr = *mac_addr;
 494         else
 495                 zero(ra->mac_addr);
 496
 497         return 0;
 498 }
 499
 500 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 501         assert_return(ra, -EINVAL);
 502         assert_return(mtu >= 1280, -EINVAL);
 503
 504         ra->mtu = mtu;
 505
 506         return 0;
 507 }
 508
 509 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 510         assert_return(ra, -EINVAL);
 511
 512         if (ra->state != RADV_STATE_IDLE)
 513                 return -EBUSY;
 514
 515         ra->hop_limit = hop_limit;
 516
 517         return 0;
 518 }
 519
 520 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 521         assert_return(ra, -EINVAL);
 522
 523         if (ra->state != RADV_STATE_IDLE)
 524                 return -EBUSY;
 525
 526         if (!router_lifetime_is_valid(lifetime_usec))
 527                 return -EINVAL;
 528
 529         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 530          * to (00) by the sender..." */
 531         if (lifetime_usec == 0 &&
 532             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 533                 return -EINVAL;
 534
 535         ra->lifetime_usec = lifetime_usec;
 536
 537         return 0;
 538 }
 539
 540 int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 541         assert_return(ra, -EINVAL);
 542
 543         if (ra->state != RADV_STATE_IDLE)
 544                 return -EBUSY;
 545
 546         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 547
 548         return 0;
 549 }
 550
 551 int sd_radv_set_other_information(sd_radv *ra, int other) {
 552         assert_return(ra, -EINVAL);
 553
 554         if (ra->state != RADV_STATE_IDLE)
 555                 return -EBUSY;
 556
 557         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 558
 559         return 0;
 560 }
 561
 562 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 563         assert_return(ra, -EINVAL);
 564         assert_return(IN_SET(preference,
 565                              SD_NDISC_PREFERENCE_LOW,
 566                              SD_NDISC_PREFERENCE_MEDIUM,
 567                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 568
 569         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 570          * to (00) by the sender..." */
 571         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 572                 return -EINVAL;
 573
 574         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 575
 576         return 0;
 577 }
 578
 579 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 580         _cleanup_free_ char *addr_p = NULL;
 581         sd_radv_prefix *cur, *found = NULL;
 582         int r;
 583
 584         assert_return(ra, -EINVAL);
 585         assert_return(p, -EINVAL);
 586
 587         /* Refuse prefixes that don't have a prefix set */
 588         if (in6_addr_is_null(&p->opt.in6_addr))
 589                 return -ENOEXEC;
 590
 591         (void) in6_addr_prefix_to_string(&p->opt.in6_addr, p->opt.prefixlen, &addr_p);
 592
 593         LIST_FOREACH(prefix, cur, ra->prefixes) {
 594
 595                 r = in_addr_prefix_intersect(AF_INET6,
 596                                              (const union in_addr_union*) &cur->opt.in6_addr,
 597                                              cur->opt.prefixlen,
 598                                              (const union in_addr_union*) &p->opt.in6_addr,
 599                                              p->opt.prefixlen);
 600                 if (r < 0)
 601                         return r;
 602                 if (r == 0)
 603                         continue;
 604
 605                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 606                         found = cur;
 607                         break;
 608                 }
 609
 610                 _cleanup_free_ char *addr_cur = NULL;
 611                 (void) in6_addr_prefix_to_string(&cur->opt.in6_addr, cur->opt.prefixlen, &addr_cur);
 612                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 613                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 614                                       strna(addr_p), strna(addr_cur));
 615         }
 616
 617         if (found) {
 618                 /* p and cur may be equivalent. First increment the reference counter. */
 619                 sd_radv_prefix_ref(p);
 620
 621                 /* Then, remove the old entry. */
 622                 LIST_REMOVE(prefix, ra->prefixes, found);
 623                 sd_radv_prefix_unref(found);
 624
 625                 /* Finally, add the new entry. */
 626                 LIST_APPEND(prefix, ra->prefixes, p);
 627
 628                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 629                          strna(addr_p),
 630                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 631                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 632         } else {
 633                 /* The prefix is new. Let's simply add it. */
 634
 635                 sd_radv_prefix_ref(p);
 636                 LIST_APPEND(prefix, ra->prefixes, p);
 637                 ra->n_prefixes++;
 638
 639                 log_radv(ra, "Added prefix %s", strna(addr_p));
 640         }
 641
 642         if (ra->state == RADV_STATE_IDLE)
 643                 return 0;
 644
 645         if (ra->ra_sent == 0)
 646                 return 0;
 647
 648         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 649         r = radv_send(ra, NULL, ra->lifetime_usec);
 650         if (r < 0)
 651                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s: %m",
 652                                strna(addr_p));
 653         else
 654                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", strna(addr_p));
 655
 656         return 0;
 657 }
 658
 659 void sd_radv_remove_prefix(
 660                 sd_radv *ra,
 661                 const struct in6_addr *prefix,
 662                 unsigned char prefixlen) {
 663
 664         sd_radv_prefix *cur;
 665
 666         if (!ra)
 667                 return;
 668
 669         if (!prefix)
 670                 return;
 671
 672         LIST_FOREACH(prefix, cur, ra->prefixes) {
 673                 if (prefixlen != cur->opt.prefixlen)
 674                         continue;
 675
 676                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 677                         continue;
 678
 679                 LIST_REMOVE(prefix, ra->prefixes, cur);
 680                 ra->n_prefixes--;
 681                 sd_radv_prefix_unref(cur);
 682                 return;
 683         }
 684 }
 685
 686 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 687         _cleanup_free_ char *addr_p = NULL;
 688         sd_radv_route_prefix *cur, *found = NULL;
 689         int r;
 690
 691         assert_return(ra, -EINVAL);
 692         assert_return(p, -EINVAL);
 693
 694         (void) in6_addr_prefix_to_string(&p->opt.in6_addr, p->opt.prefixlen, &addr_p);
 695
 696         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 697
 698                 r = in_addr_prefix_intersect(AF_INET6,
 699                                              (const union in_addr_union*) &cur->opt.in6_addr,
 700                                              cur->opt.prefixlen,
 701                                              (const union in_addr_union*) &p->opt.in6_addr,
 702                                              p->opt.prefixlen);
 703                 if (r < 0)
 704                         return r;
 705                 if (r == 0)
 706                         continue;
 707
 708                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 709                         found = cur;
 710                         break;
 711                 }
 712
 713                 _cleanup_free_ char *addr_cur = NULL;
 714                 (void) in6_addr_prefix_to_string(&cur->opt.in6_addr, cur->opt.prefixlen, &addr_cur);
 715                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 716                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 717                                       strna(addr_p), strna(addr_cur));
 718         }
 719
 720         if (found) {
 721                 /* p and cur may be equivalent. First increment the reference counter. */
 722                 sd_radv_route_prefix_ref(p);
 723
 724                 /* Then, remove the old entry. */
 725                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 726                 sd_radv_route_prefix_unref(found);
 727
 728                 /* Finally, add the new entry. */
 729                 LIST_APPEND(prefix, ra->route_prefixes, p);
 730
 731                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 732                          strna(addr_p),
 733                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 734         } else {
 735                 /* The route prefix is new. Let's simply add it. */
 736
 737                 sd_radv_route_prefix_ref(p);
 738                 LIST_APPEND(prefix, ra->route_prefixes, p);
 739                 ra->n_route_prefixes++;
 740
 741                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 742         }
 743
 744         if (ra->state == RADV_STATE_IDLE)
 745                 return 0;
 746
 747         if (ra->ra_sent == 0)
 748                 return 0;
 749
 750         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 751         r = radv_send(ra, NULL, ra->lifetime_usec);
 752         if (r < 0)
 753                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s: %m",
 754                                strna(addr_p));
 755         else
 756                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 757
 758         return 0;
 759 }
 760
 761 int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime,
 762                                const struct in6_addr *dns, size_t n_dns) {
 763         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 764         size_t len;
 765
 766         assert_return(ra, -EINVAL);
 767         assert_return(n_dns < 128, -EINVAL);
 768
 769         if (!dns || n_dns == 0) {
 770                 ra->rdnss = mfree(ra->rdnss);
 771                 ra->n_rdnss = 0;
 772
 773                 return 0;
 774         }
 775
 776         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 777
 778         opt_rdnss = malloc0(len);
 779         if (!opt_rdnss)
 780                 return -ENOMEM;
 781
 782         opt_rdnss->type = RADV_OPT_RDNSS;
 783         opt_rdnss->length = len / 8;
 784         opt_rdnss->lifetime = htobe32(lifetime);
 785
 786         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 787
 788         free_and_replace(ra->rdnss, opt_rdnss);
 789
 790         ra->n_rdnss = n_dns;
 791
 792         return 0;
 793 }
 794
 795 int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime,
 796                                char **search_list) {
 797         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 798         size_t len = 0;
 799         char **s;
 800         uint8_t *p;
 801
 802         assert_return(ra, -EINVAL);
 803
 804         if (strv_isempty(search_list)) {
 805                 ra->dnssl = mfree(ra->dnssl);
 806                 return 0;
 807         }
 808
 809         STRV_FOREACH(s, search_list)
 810                 len += strlen(*s) + 2;
 811
 812         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 813
 814         opt_dnssl = malloc0(len);
 815         if (!opt_dnssl)
 816                 return -ENOMEM;
 817
 818         opt_dnssl->type = RADV_OPT_DNSSL;
 819         opt_dnssl->length = len / 8;
 820         opt_dnssl->lifetime = htobe32(lifetime);
 821
 822         p = (uint8_t *)(opt_dnssl + 1);
 823         len -= sizeof(struct sd_radv_opt_dns);
 824
 825         STRV_FOREACH(s, search_list) {
 826                 int r;
 827
 828                 r = dns_name_to_wire_format(*s, p, len, false);
 829                 if (r < 0)
 830                         return r;
 831
 832                 if (len < (size_t)r)
 833                         return -ENOBUFS;
 834
 835                 p += r;
 836                 len -= r;
 837         }
 838
 839         free_and_replace(ra->dnssl, opt_dnssl);
 840
 841         return 0;
 842 }
 843
 844 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 845         sd_radv_prefix *p;
 846
 847         assert_return(ret, -EINVAL);
 848
 849         p = new(sd_radv_prefix, 1);
 850         if (!p)
 851                 return -ENOMEM;
 852
 853         *p = (sd_radv_prefix) {
 854                 .n_ref = 1,
 855
 856                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 857                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 858                 .opt.prefixlen = 64,
 859
 860                 /* RFC 4861, Section 6.2.1 */
 861                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 862
 863                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 864                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 865                 .valid_until = USEC_INFINITY,
 866                 .preferred_until = USEC_INFINITY,
 867         };
 868
 869         *ret = p;
 870         return 0;
 871 }
 872
 873 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
 874
 875 int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr,
 876                                        unsigned char prefixlen) {
 877         assert_return(p, -EINVAL);
 878         assert_return(in6_addr, -EINVAL);
 879
 880         if (prefixlen < 3 || prefixlen > 128)
 881                 return -EINVAL;
 882
 883         if (prefixlen > 64)
 884                 /* unusual but allowed, log it */
 885                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
 886
 887         p->opt.in6_addr = *in6_addr;
 888         p->opt.prefixlen = prefixlen;
 889
 890         return 0;
 891 }
 892
 893 int sd_radv_prefix_get_prefix(sd_radv_prefix *p, struct in6_addr *ret_in6_addr,
 894                                        unsigned char *ret_prefixlen) {
 895         assert_return(p, -EINVAL);
 896         assert_return(ret_in6_addr, -EINVAL);
 897         assert_return(ret_prefixlen, -EINVAL);
 898
 899         *ret_in6_addr = p->opt.in6_addr;
 900         *ret_prefixlen = p->opt.prefixlen;
 901
 902         return 0;
 903 }
 904
 905 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
 906         assert_return(p, -EINVAL);
 907
 908         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
 909
 910         return 0;
 911 }
 912
 913 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,
 914                                                           int address_autoconfiguration) {
 915         assert_return(p, -EINVAL);
 916
 917         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
 918
 919         return 0;
 920 }
 921
 922 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
 923         assert_return(p, -EINVAL);
 924
 925         p->lifetime_valid_usec = lifetime_usec;
 926         p->valid_until = valid_until;
 927
 928         return 0;
 929 }
 930
 931 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
 932         assert_return(p, -EINVAL);
 933
 934         p->lifetime_preferred_usec = lifetime_usec;
 935         p->preferred_until = valid_until;
 936
 937         return 0;
 938 }
 939
 940 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
 941         sd_radv_route_prefix *p;
 942
 943         assert_return(ret, -EINVAL);
 944
 945         p = new(sd_radv_route_prefix, 1);
 946         if (!p)
 947                 return -ENOMEM;
 948
 949         *p = (sd_radv_route_prefix) {
 950                 .n_ref = 1,
 951
 952                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
 953                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
 954                 .opt.prefixlen = 64,
 955
 956                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 957                 .valid_until = USEC_INFINITY,
 958         };
 959
 960         *ret = p;
 961         return 0;
 962 }
 963
 964 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
 965
 966 int sd_radv_route_prefix_set_prefix(sd_radv_route_prefix *p, const struct in6_addr *in6_addr,
 967                                              unsigned char prefixlen) {
 968         assert_return(p, -EINVAL);
 969         assert_return(in6_addr, -EINVAL);
 970
 971         if (prefixlen > 128)
 972                 return -EINVAL;
 973
 974         if (prefixlen > 64)
 975                 /* unusual but allowed, log it */
 976                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
 977
 978         p->opt.in6_addr = *in6_addr;
 979         p->opt.prefixlen = prefixlen;
 980
 981         return 0;
 982 }
 983
 984 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
 985         assert_return(p, -EINVAL);
 986
 987         p->lifetime_usec = lifetime_usec;
 988         p->valid_until = valid_until;
 989
 990         return 0;
 991 }