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 "iovec-util.h"
  20 #include "macro.h"
  21 #include "memory-util.h"
  22 #include "ndisc-router-solicit-internal.h"
  23 #include "network-common.h"
  24 #include "radv-internal.h"
  25 #include "random-util.h"
  26 #include "socket-util.h"
  27 #include "string-util.h"
  28 #include "strv.h"
  29 #include "unaligned.h"
  30
  31 int sd_radv_new(sd_radv **ret) {
  32         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  33
  34         assert_return(ret, -EINVAL);
  35
  36         ra = new(sd_radv, 1);
  37         if (!ra)
  38                 return -ENOMEM;
  39
  40         *ra = (sd_radv) {
  41                 .n_ref = 1,
  42                 .fd = -EBADF,
  43                 .lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
  44         };
  45
  46         *ret = TAKE_PTR(ra);
  47
  48         return 0;
  49 }
  50
  51 int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  52         int r;
  53
  54         assert_return(ra, -EINVAL);
  55         assert_return(!ra->event, -EBUSY);
  56
  57         if (event)
  58                 ra->event = sd_event_ref(event);
  59         else {
  60                 r = sd_event_default(&ra->event);
  61                 if (r < 0)
  62                         return 0;
  63         }
  64
  65         ra->event_priority = priority;
  66
  67         return 0;
  68 }
  69
  70 int sd_radv_detach_event(sd_radv *ra) {
  71
  72         assert_return(ra, -EINVAL);
  73
  74         ra->event = sd_event_unref(ra->event);
  75         return 0;
  76 }
  77
  78 sd_event *sd_radv_get_event(sd_radv *ra) {
  79         assert_return(ra, NULL);
  80
  81         return ra->event;
  82 }
  83
  84 int sd_radv_is_running(sd_radv *ra) {
  85         if (!ra)
  86                 return false;
  87
  88         return ra->state != RADV_STATE_IDLE;
  89 }
  90
  91 static void radv_reset(sd_radv *ra) {
  92         assert(ra);
  93
  94         (void) event_source_disable(ra->timeout_event_source);
  95
  96         ra->recv_event_source = sd_event_source_disable_unref(ra->recv_event_source);
  97
  98         ra->ra_sent = 0;
  99 }
 100
 101 static sd_radv *radv_free(sd_radv *ra) {
 102         if (!ra)
 103                 return NULL;
 104
 105         LIST_CLEAR(prefix, ra->prefixes, sd_radv_prefix_unref);
 106         LIST_CLEAR(prefix, ra->route_prefixes, sd_radv_route_prefix_unref);
 107         LIST_CLEAR(prefix, ra->pref64_prefixes, sd_radv_pref64_prefix_unref);
 108
 109         free(ra->rdnss);
 110         free(ra->dnssl);
 111
 112         radv_reset(ra);
 113
 114         sd_event_source_unref(ra->timeout_event_source);
 115         sd_radv_detach_event(ra);
 116
 117         ra->fd = safe_close(ra->fd);
 118         free(ra->ifname);
 119
 120         return mfree(ra);
 121 }
 122
 123 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
 124
 125 static bool router_lifetime_is_valid(usec_t lifetime_usec) {
 126         assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
 127         return lifetime_usec == 0 ||
 128                 (lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
 129                  lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
 130 }
 131
 132 static int radv_send_router_on_stop(sd_radv *ra) {
 133         static const struct nd_router_advert adv = {
 134                 .nd_ra_type = ND_ROUTER_ADVERT,
 135         };
 136
 137         _cleanup_set_free_ Set *options = NULL;
 138         usec_t time_now;
 139         int r;
 140
 141         assert(ra);
 142
 143         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 144         if (r < 0)
 145                 return r;
 146
 147         if (!ether_addr_is_null(&ra->mac_addr)) {
 148                 r = ndisc_option_set_link_layer_address(&options, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, &ra->mac_addr);
 149                 if (r < 0)
 150                         return r;
 151         }
 152
 153         return ndisc_send(ra->fd, &IN6_ADDR_ALL_NODES_MULTICAST, &adv.nd_ra_hdr, options, time_now);
 154 }
 155
 156 static int radv_send_router(sd_radv *ra, const struct in6_addr *dst) {
 157         assert(ra);
 158
 159         struct sockaddr_in6 dst_addr = {
 160                 .sin6_family = AF_INET6,
 161                 .sin6_addr = IN6_ADDR_ALL_NODES_MULTICAST,
 162         };
 163         struct nd_router_advert adv = {
 164                 .nd_ra_type = ND_ROUTER_ADVERT,
 165                 .nd_ra_router_lifetime = usec_to_be16_sec(ra->lifetime_usec),
 166                 .nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec),
 167         };
 168         struct {
 169                 struct nd_opt_hdr opthdr;
 170                 struct ether_addr slladdr;
 171         } _packed_ opt_mac = {
 172                 .opthdr = {
 173                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 174                         .nd_opt_len = DIV_ROUND_UP(sizeof(struct nd_opt_hdr) + sizeof(struct ether_addr), 8),
 175                 },
 176                 .slladdr = ra->mac_addr,
 177         };
 178         struct nd_opt_mtu opt_mtu =  {
 179                 .nd_opt_mtu_type = ND_OPT_MTU,
 180                 .nd_opt_mtu_len = 1,
 181                 .nd_opt_mtu_mtu = htobe32(ra->mtu),
 182         };
 183         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, N pref64 prefixes, RDNSS,
 184          * DNSSL, and home agent. */
 185         struct iovec iov[6 + ra->n_prefixes + ra->n_route_prefixes + ra->n_pref64_prefixes];
 186         struct msghdr msg = {
 187                 .msg_name = &dst_addr,
 188                 .msg_namelen = sizeof(dst_addr),
 189                 .msg_iov = iov,
 190         };
 191         usec_t time_now;
 192         int r;
 193
 194         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 195         if (r < 0)
 196                 return r;
 197
 198         if (dst && in6_addr_is_set(dst))
 199                 dst_addr.sin6_addr = *dst;
 200
 201         /* The nd_ra_curhoplimit and nd_ra_flags_reserved fields cannot specified with nd_ra_router_lifetime
 202          * simultaneously in the structured initializer in the above. */
 203         adv.nd_ra_curhoplimit = ra->hop_limit;
 204         adv.nd_ra_flags_reserved = ra->flags;
 205         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 206
 207         /* MAC address is optional, either because the link does not use L2 addresses or load sharing is
 208          * desired. See RFC 4861, Section 4.2. */
 209         if (!ether_addr_is_null(&ra->mac_addr))
 210                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 211
 212         if (ra->mtu > 0)
 213                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 214
 215         LIST_FOREACH(prefix, p, ra->prefixes) {
 216                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 217
 218                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 219                                           p->lifetime_valid_usec);
 220
 221                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 222                                                p->lifetime_preferred_usec,
 223                                                lifetime_valid_usec);
 224
 225                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 226                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 227
 228                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 229         }
 230
 231         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 232                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 233                                                         rt->lifetime_usec));
 234
 235                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 236         }
 237
 238         LIST_FOREACH(prefix, p, ra->pref64_prefixes)
 239                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 240
 241         if (ra->rdnss)
 242                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 243
 244         if (ra->dnssl)
 245                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 246
 247         if (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
 248                 ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
 249                 ra->home_agent.nd_opt_home_agent_info_len = 1;
 250
 251                 /* 0 means to place the current Router Lifetime value */
 252                 if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
 253                         ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
 254
 255                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
 256         }
 257
 258         if (sendmsg(ra->fd, &msg, 0) < 0)
 259                 return -errno;
 260
 261         return 0;
 262 }
 263
 264 static int radv_process_packet(sd_radv *ra, ICMP6Packet *packet) {
 265         int r;
 266
 267         assert(ra);
 268         assert(packet);
 269
 270         if (icmp6_packet_get_type(packet) != ND_ROUTER_SOLICIT)
 271                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EBADMSG), "Received ICMP6 packet with unexpected type, ignoring.");
 272
 273         _cleanup_(sd_ndisc_router_solicit_unrefp) sd_ndisc_router_solicit *rs = NULL;
 274         rs = ndisc_router_solicit_new(packet);
 275         if (!rs)
 276                 return log_oom_debug();
 277
 278         r = ndisc_router_solicit_parse(ra, rs);
 279         if (r < 0)
 280                 return r;
 281
 282         struct in6_addr src = {};
 283         r = sd_ndisc_router_solicit_get_sender_address(rs, &src);
 284         if (r < 0 && r != -ENODATA) /* null address is allowed */
 285                 return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
 286         if (r >= 0 && in6_addr_equal(&src, &ra->ipv6ll))
 287                 /* This should be definitely caused by a misconfiguration. If we send RA to ourself, the
 288                  * kernel complains about that. Let's ignore the packet. */
 289                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EADDRINUSE), "Received RS from the same interface, ignoring.");
 290
 291         r = radv_send_router(ra, &src);
 292         if (r < 0)
 293                 return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
 294
 295         log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
 296         return 0;
 297 }
 298
 299 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 300         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
 301         sd_radv *ra = ASSERT_PTR(userdata);
 302         int r;
 303
 304         assert(fd >= 0);
 305
 306         r = icmp6_packet_receive(fd, &packet);
 307         if (r < 0) {
 308                 log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
 309                 return 0;
 310         }
 311
 312         (void) radv_process_packet(ra, packet);
 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 = ASSERT_PTR(userdata);
 319         int r;
 320
 321         assert(s);
 322         assert(ra->event);
 323         assert(router_lifetime_is_valid(ra->lifetime_usec));
 324
 325         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 326         if (r < 0)
 327                 goto fail;
 328
 329         r = radv_send_router(ra, NULL);
 330         if (r < 0)
 331                 log_radv_errno(ra, r, "Unable to send Router Advertisement, ignoring: %m");
 332
 333         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 334         if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 335                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 336         else
 337                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 338
 339         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 340          * so lower the interval here */
 341         if (ra->lifetime_usec > 0)
 342                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 343
 344         if (max_timeout >= 9 * USEC_PER_SEC)
 345                 min_timeout = max_timeout / 3;
 346         else
 347                 min_timeout = max_timeout * 3 / 4;
 348
 349         /* RFC 4861, Section 6.2.1.
 350          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 351          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 352         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 353         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 354         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 355         assert(min_timeout <= max_timeout * 3 / 4);
 356
 357         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 358         log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 359
 360         r = event_reset_time(ra->event, &ra->timeout_event_source,
 361                              CLOCK_BOOTTIME,
 362                              usec_add(time_now, timeout), MSEC_PER_SEC,
 363                              radv_timeout, ra,
 364                              ra->event_priority, "radv-timeout", true);
 365         if (r < 0)
 366                 goto fail;
 367
 368         ra->ra_sent++;
 369
 370         return 0;
 371
 372 fail:
 373         sd_radv_stop(ra);
 374
 375         return 0;
 376 }
 377
 378 int sd_radv_stop(sd_radv *ra) {
 379         int r;
 380
 381         if (!ra)
 382                 return 0;
 383
 384         if (ra->state == RADV_STATE_IDLE)
 385                 return 0;
 386
 387         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 388
 389         /* RFC 4861, Section 6.2.5:
 390          * the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
 391          * multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
 392         r = radv_send_router_on_stop(ra);
 393         if (r < 0)
 394                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %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 static int radv_setup_recv_event(sd_radv *ra) {
 404         int r;
 405
 406         assert(ra);
 407         assert(ra->event);
 408         assert(ra->ifindex > 0);
 409
 410         _cleanup_close_ int fd = -EBADF;
 411         fd = icmp6_bind(ra->ifindex, /* is_router = */ true);
 412         if (fd < 0)
 413                 return fd;
 414
 415         _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
 416         r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
 417         if (r < 0)
 418                 return r;
 419
 420         r = sd_event_source_set_priority(s, ra->event_priority);
 421         if (r < 0)
 422                 return r;
 423
 424         (void) sd_event_source_set_description(s, "radv-receive-message");
 425
 426         ra->fd = TAKE_FD(fd);
 427         ra->recv_event_source = TAKE_PTR(s);
 428         return 0;
 429 }
 430
 431 int sd_radv_start(sd_radv *ra) {
 432         int r;
 433
 434         assert_return(ra, -EINVAL);
 435         assert_return(ra->event, -EINVAL);
 436         assert_return(ra->ifindex > 0, -EINVAL);
 437
 438         if (ra->state != RADV_STATE_IDLE)
 439                 return 0;
 440
 441         r = radv_setup_recv_event(ra);
 442         if (r < 0)
 443                 goto fail;
 444
 445         r = event_reset_time(ra->event, &ra->timeout_event_source,
 446                              CLOCK_BOOTTIME,
 447                              0, 0,
 448                              radv_timeout, ra,
 449                              ra->event_priority, "radv-timeout", true);
 450         if (r < 0)
 451                 goto fail;
 452
 453         ra->state = RADV_STATE_ADVERTISING;
 454
 455         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 456
 457         return 0;
 458
 459  fail:
 460         radv_reset(ra);
 461
 462         return r;
 463 }
 464
 465 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 466         assert_return(ra, -EINVAL);
 467         assert_return(ifindex > 0, -EINVAL);
 468
 469         if (ra->state != RADV_STATE_IDLE)
 470                 return -EBUSY;
 471
 472         ra->ifindex = ifindex;
 473
 474         return 0;
 475 }
 476
 477 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 478         assert_return(ra, -EINVAL);
 479         assert_return(ifname, -EINVAL);
 480
 481         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 482                 return -EINVAL;
 483
 484         return free_and_strdup(&ra->ifname, ifname);
 485 }
 486
 487 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 488         int r;
 489
 490         assert_return(ra, -EINVAL);
 491
 492         r = get_ifname(ra->ifindex, &ra->ifname);
 493         if (r < 0)
 494                 return r;
 495
 496         if (ret)
 497                 *ret = ra->ifname;
 498
 499         return 0;
 500 }
 501
 502 int sd_radv_set_link_local_address(sd_radv *ra, const struct in6_addr *addr) {
 503         assert_return(ra, -EINVAL);
 504         assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);
 505
 506         if (addr)
 507                 ra->ipv6ll = *addr;
 508         else
 509                 zero(ra->ipv6ll);
 510
 511         return 0;
 512 }
 513
 514 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 515         assert_return(ra, -EINVAL);
 516
 517         if (ra->state != RADV_STATE_IDLE)
 518                 return -EBUSY;
 519
 520         if (mac_addr)
 521                 ra->mac_addr = *mac_addr;
 522         else
 523                 zero(ra->mac_addr);
 524
 525         return 0;
 526 }
 527
 528 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 529         assert_return(ra, -EINVAL);
 530         assert_return(mtu >= 1280, -EINVAL);
 531
 532         ra->mtu = mtu;
 533
 534         return 0;
 535 }
 536
 537 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 538         assert_return(ra, -EINVAL);
 539
 540         ra->hop_limit = hop_limit;
 541         return 0;
 542 }
 543
 544 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 545         assert_return(ra, -EINVAL);
 546
 547         ra->retransmit_usec = usec;
 548         return 0;
 549 }
 550
 551 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 552         assert_return(ra, -EINVAL);
 553
 554         if (!router_lifetime_is_valid(usec))
 555                 return -EINVAL;
 556
 557         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 558          * to (00) by the sender..." */
 559         if (usec == 0 &&
 560             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 561                 return -EINVAL;
 562
 563         ra->lifetime_usec = usec;
 564         return 0;
 565 }
 566
 567 int sd_radv_set_managed_information(sd_radv *ra, int b) {
 568         assert_return(ra, -EINVAL);
 569
 570         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, b);
 571         return 0;
 572 }
 573
 574 int sd_radv_set_other_information(sd_radv *ra, int b) {
 575         assert_return(ra, -EINVAL);
 576
 577         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, b);
 578         return 0;
 579 }
 580
 581 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 582         assert_return(ra, -EINVAL);
 583         assert_return(IN_SET(preference,
 584                              SD_NDISC_PREFERENCE_LOW,
 585                              SD_NDISC_PREFERENCE_MEDIUM,
 586                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 587
 588         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 589          * to (00) by the sender..." */
 590         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 591                 return -EINVAL;
 592
 593         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 594
 595         return 0;
 596 }
 597
 598 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 599         assert_return(ra, -EINVAL);
 600
 601         if (ra->state != RADV_STATE_IDLE)
 602                 return -EBUSY;
 603
 604         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 605
 606         return 0;
 607 }
 608
 609 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 610         assert_return(ra, -EINVAL);
 611
 612         if (ra->state != RADV_STATE_IDLE)
 613                 return -EBUSY;
 614
 615         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 616
 617         return 0;
 618 }
 619
 620 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 621         assert_return(ra, -EINVAL);
 622
 623         if (ra->state != RADV_STATE_IDLE)
 624                 return -EBUSY;
 625
 626         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 627                 return -EINVAL;
 628
 629         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 630         return 0;
 631 }
 632
 633 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 634         sd_radv_prefix *found = NULL;
 635         int r;
 636
 637         assert_return(ra, -EINVAL);
 638         assert_return(p, -EINVAL);
 639
 640         /* Refuse prefixes that don't have a prefix set */
 641         if (in6_addr_is_null(&p->opt.in6_addr))
 642                 return -ENOEXEC;
 643
 644         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 645
 646         LIST_FOREACH(prefix, cur, ra->prefixes) {
 647                 r = in_addr_prefix_intersect(AF_INET6,
 648                                              (const union in_addr_union*) &cur->opt.in6_addr,
 649                                              cur->opt.prefixlen,
 650                                              (const union in_addr_union*) &p->opt.in6_addr,
 651                                              p->opt.prefixlen);
 652                 if (r < 0)
 653                         return r;
 654                 if (r == 0)
 655                         continue;
 656
 657                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 658                         found = cur;
 659                         break;
 660                 }
 661
 662                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 663                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 664                                       addr_p,
 665                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 666         }
 667
 668         if (found) {
 669                 /* p and cur may be equivalent. First increment the reference counter. */
 670                 sd_radv_prefix_ref(p);
 671
 672                 /* Then, remove the old entry. */
 673                 LIST_REMOVE(prefix, ra->prefixes, found);
 674                 sd_radv_prefix_unref(found);
 675
 676                 /* Finally, add the new entry. */
 677                 LIST_APPEND(prefix, ra->prefixes, p);
 678
 679                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 680                          addr_p,
 681                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 682                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 683         } else {
 684                 /* The prefix is new. Let's simply add it. */
 685
 686                 sd_radv_prefix_ref(p);
 687                 LIST_APPEND(prefix, ra->prefixes, p);
 688                 ra->n_prefixes++;
 689
 690                 log_radv(ra, "Added prefix %s", addr_p);
 691         }
 692
 693         if (ra->state == RADV_STATE_IDLE)
 694                 return 0;
 695
 696         if (ra->ra_sent == 0)
 697                 return 0;
 698
 699         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 700         r = radv_send_router(ra, NULL);
 701         if (r < 0)
 702                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 703         else
 704                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 705
 706         return 0;
 707 }
 708
 709 void sd_radv_remove_prefix(
 710                 sd_radv *ra,
 711                 const struct in6_addr *prefix,
 712                 unsigned char prefixlen) {
 713
 714         if (!ra)
 715                 return;
 716
 717         if (!prefix)
 718                 return;
 719
 720         LIST_FOREACH(prefix, cur, ra->prefixes) {
 721                 if (prefixlen != cur->opt.prefixlen)
 722                         continue;
 723
 724                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 725                         continue;
 726
 727                 LIST_REMOVE(prefix, ra->prefixes, cur);
 728                 ra->n_prefixes--;
 729                 sd_radv_prefix_unref(cur);
 730                 return;
 731         }
 732 }
 733
 734 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 735         sd_radv_route_prefix *found = NULL;
 736         int r;
 737
 738         assert_return(ra, -EINVAL);
 739         assert_return(p, -EINVAL);
 740
 741         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 742
 743         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 744                 r = in_addr_prefix_intersect(AF_INET6,
 745                                              (const union in_addr_union*) &cur->opt.in6_addr,
 746                                              cur->opt.prefixlen,
 747                                              (const union in_addr_union*) &p->opt.in6_addr,
 748                                              p->opt.prefixlen);
 749                 if (r < 0)
 750                         return r;
 751                 if (r == 0)
 752                         continue;
 753
 754                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 755                         found = cur;
 756                         break;
 757                 }
 758
 759                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 760                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 761                                       addr_p,
 762                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 763         }
 764
 765         if (found) {
 766                 /* p and cur may be equivalent. First increment the reference counter. */
 767                 sd_radv_route_prefix_ref(p);
 768
 769                 /* Then, remove the old entry. */
 770                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 771                 sd_radv_route_prefix_unref(found);
 772
 773                 /* Finally, add the new entry. */
 774                 LIST_APPEND(prefix, ra->route_prefixes, p);
 775
 776                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 777                          strna(addr_p),
 778                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 779         } else {
 780                 /* The route prefix is new. Let's simply add it. */
 781
 782                 sd_radv_route_prefix_ref(p);
 783                 LIST_APPEND(prefix, ra->route_prefixes, p);
 784                 ra->n_route_prefixes++;
 785
 786                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 787         }
 788
 789         if (ra->state == RADV_STATE_IDLE)
 790                 return 0;
 791
 792         if (ra->ra_sent == 0)
 793                 return 0;
 794
 795         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 796         r = radv_send_router(ra, NULL);
 797         if (r < 0)
 798                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 799                                strna(addr_p));
 800         else
 801                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 802
 803         return 0;
 804 }
 805
 806 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 807         sd_radv_pref64_prefix *found = NULL;
 808         int r;
 809
 810         assert_return(ra, -EINVAL);
 811         assert_return(p, -EINVAL);
 812
 813         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 814
 815         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 816                 r = in_addr_prefix_intersect(AF_INET6,
 817                                              (const union in_addr_union*) &cur->in6_addr,
 818                                              cur->prefixlen,
 819                                              (const union in_addr_union*) &p->in6_addr,
 820                                              p->prefixlen);
 821                 if (r < 0)
 822                         return r;
 823                 if (r == 0)
 824                         continue;
 825
 826                 if (cur->prefixlen == p->prefixlen) {
 827                         found = cur;
 828                         break;
 829                 }
 830
 831                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 832                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 833                                       addr_p,
 834                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 835         }
 836
 837         if (found) {
 838                 /* p and cur may be equivalent. First increment the reference counter. */
 839                 sd_radv_pref64_prefix_ref(p);
 840
 841                 /* Then, remove the old entry. */
 842                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 843                 sd_radv_pref64_prefix_unref(found);
 844
 845                 /* Finally, add the new entry. */
 846                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 847
 848                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 849                          strna(addr_p),
 850                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 851         } else {
 852                 /* The route prefix is new. Let's simply add it. */
 853
 854                 sd_radv_pref64_prefix_ref(p);
 855                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 856                 ra->n_pref64_prefixes++;
 857
 858                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 859         }
 860
 861         if (ra->state == RADV_STATE_IDLE)
 862                 return 0;
 863
 864         if (ra->ra_sent == 0)
 865                 return 0;
 866
 867         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 868         r = radv_send_router(ra, NULL);
 869         if (r < 0)
 870                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 871                                strna(addr_p));
 872         else
 873                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 874
 875         return 0;
 876 }
 877
 878 int sd_radv_set_rdnss(
 879                 sd_radv *ra,
 880                 uint64_t lifetime_usec,
 881                 const struct in6_addr *dns,
 882                 size_t n_dns) {
 883
 884         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 885         size_t len;
 886
 887         assert_return(ra, -EINVAL);
 888         assert_return(n_dns < 128, -EINVAL);
 889
 890         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 891                 return -EINVAL;
 892
 893         if (!dns || n_dns == 0) {
 894                 ra->rdnss = mfree(ra->rdnss);
 895                 ra->n_rdnss = 0;
 896
 897                 return 0;
 898         }
 899
 900         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 901
 902         opt_rdnss = malloc0(len);
 903         if (!opt_rdnss)
 904                 return -ENOMEM;
 905
 906         opt_rdnss->type = RADV_OPT_RDNSS;
 907         opt_rdnss->length = len / 8;
 908         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 909
 910         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 911
 912         free_and_replace(ra->rdnss, opt_rdnss);
 913
 914         ra->n_rdnss = n_dns;
 915
 916         return 0;
 917 }
 918
 919 int sd_radv_set_dnssl(
 920                 sd_radv *ra,
 921                 uint64_t lifetime_usec,
 922                 char **search_list) {
 923
 924         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 925         size_t len = 0;
 926         uint8_t *p;
 927
 928         assert_return(ra, -EINVAL);
 929
 930         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 931                 return -EINVAL;
 932
 933         if (strv_isempty(search_list)) {
 934                 ra->dnssl = mfree(ra->dnssl);
 935                 return 0;
 936         }
 937
 938         STRV_FOREACH(s, search_list)
 939                 len += strlen(*s) + 2;
 940
 941         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 942
 943         opt_dnssl = malloc0(len);
 944         if (!opt_dnssl)
 945                 return -ENOMEM;
 946
 947         opt_dnssl->type = RADV_OPT_DNSSL;
 948         opt_dnssl->length = len / 8;
 949         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 950
 951         p = (uint8_t *)(opt_dnssl + 1);
 952         len -= sizeof(struct sd_radv_opt_dns);
 953
 954         STRV_FOREACH(s, search_list) {
 955                 int r;
 956
 957                 r = dns_name_to_wire_format(*s, p, len, false);
 958                 if (r < 0)
 959                         return r;
 960
 961                 if (len < (size_t)r)
 962                         return -ENOBUFS;
 963
 964                 p += r;
 965                 len -= r;
 966         }
 967
 968         free_and_replace(ra->dnssl, opt_dnssl);
 969
 970         return 0;
 971 }
 972
 973 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 974         sd_radv_prefix *p;
 975
 976         assert_return(ret, -EINVAL);
 977
 978         p = new(sd_radv_prefix, 1);
 979         if (!p)
 980                 return -ENOMEM;
 981
 982         *p = (sd_radv_prefix) {
 983                 .n_ref = 1,
 984
 985                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 986                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 987                 .opt.prefixlen = 64,
 988
 989                 /* RFC 4861, Section 6.2.1 */
 990                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 991
 992                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 993                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 994                 .valid_until = USEC_INFINITY,
 995                 .preferred_until = USEC_INFINITY,
 996         };
 997
 998         *ret = p;
 999         return 0;
1000 }
1001
1002 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
1003
1004 int sd_radv_prefix_set_prefix(
1005                 sd_radv_prefix *p,
1006                 const struct in6_addr *in6_addr,
1007                 unsigned char prefixlen) {
1008
1009         assert_return(p, -EINVAL);
1010         assert_return(in6_addr, -EINVAL);
1011
1012         if (prefixlen < 3 || prefixlen > 128)
1013                 return -EINVAL;
1014
1015         if (prefixlen > 64)
1016                 /* unusual but allowed, log it */
1017                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
1018
1019         p->opt.in6_addr = *in6_addr;
1020         p->opt.prefixlen = prefixlen;
1021
1022         return 0;
1023 }
1024
1025 int sd_radv_prefix_get_prefix(
1026                 sd_radv_prefix *p,
1027                 struct in6_addr *ret_in6_addr,
1028                 unsigned char *ret_prefixlen) {
1029
1030         assert_return(p, -EINVAL);
1031         assert_return(ret_in6_addr, -EINVAL);
1032         assert_return(ret_prefixlen, -EINVAL);
1033
1034         *ret_in6_addr = p->opt.in6_addr;
1035         *ret_prefixlen = p->opt.prefixlen;
1036
1037         return 0;
1038 }
1039
1040 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1041         assert_return(p, -EINVAL);
1042
1043         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1044
1045         return 0;
1046 }
1047
1048 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1049         assert_return(p, -EINVAL);
1050
1051         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1052
1053         return 0;
1054 }
1055
1056 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1057         assert_return(p, -EINVAL);
1058
1059         p->lifetime_valid_usec = lifetime_usec;
1060         p->valid_until = valid_until;
1061
1062         return 0;
1063 }
1064
1065 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1066         assert_return(p, -EINVAL);
1067
1068         p->lifetime_preferred_usec = lifetime_usec;
1069         p->preferred_until = valid_until;
1070
1071         return 0;
1072 }
1073
1074 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1075         sd_radv_route_prefix *p;
1076
1077         assert_return(ret, -EINVAL);
1078
1079         p = new(sd_radv_route_prefix, 1);
1080         if (!p)
1081                 return -ENOMEM;
1082
1083         *p = (sd_radv_route_prefix) {
1084                 .n_ref = 1,
1085
1086                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1087                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1088                 .opt.prefixlen = 64,
1089
1090                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1091                 .valid_until = USEC_INFINITY,
1092         };
1093
1094         *ret = p;
1095         return 0;
1096 }
1097
1098 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1099
1100 int sd_radv_route_prefix_set_prefix(
1101                 sd_radv_route_prefix *p,
1102                 const struct in6_addr *in6_addr,
1103                 unsigned char prefixlen) {
1104
1105         assert_return(p, -EINVAL);
1106         assert_return(in6_addr, -EINVAL);
1107
1108         if (prefixlen > 128)
1109                 return -EINVAL;
1110
1111         if (prefixlen > 64)
1112                 /* unusual but allowed, log it */
1113                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1114
1115         p->opt.in6_addr = *in6_addr;
1116         p->opt.prefixlen = prefixlen;
1117
1118         return 0;
1119 }
1120
1121 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1122         assert_return(p, -EINVAL);
1123
1124         p->lifetime_usec = lifetime_usec;
1125         p->valid_until = valid_until;
1126
1127         return 0;
1128 }
1129
1130 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1131         sd_radv_pref64_prefix *p;
1132
1133         assert_return(ret, -EINVAL);
1134
1135         p = new(sd_radv_pref64_prefix, 1);
1136         if (!p)
1137                 return -ENOMEM;
1138
1139         *p = (sd_radv_pref64_prefix) {
1140                 .n_ref = 1,
1141
1142                 .opt.type = RADV_OPT_PREF64,
1143                 .opt.length = 2,
1144         };
1145
1146         *ret = p;
1147         return 0;
1148 }
1149
1150 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1151
1152 int sd_radv_pref64_prefix_set_prefix(
1153                 sd_radv_pref64_prefix *p,
1154                 const struct in6_addr *prefix,
1155                 uint8_t prefixlen,
1156                 uint64_t lifetime_usec) {
1157
1158         uint16_t pref64_lifetime;
1159         uint8_t prefixlen_code;
1160         int r;
1161
1162         assert_return(p, -EINVAL);
1163         assert_return(prefix, -EINVAL);
1164
1165         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1166         if (r < 0)
1167                 return log_radv_errno(NULL, r,
1168                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1169
1170         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1171                 return -EINVAL;
1172
1173         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1174         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1175         pref64_lifetime |= prefixlen_code;
1176
1177         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1178         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1179
1180         p->in6_addr = *prefix;
1181         p->prefixlen = prefixlen;
1182
1183         return 0;
1184 }