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         /* RFC 4191, Section 2.2,
 205          * "...If the Router Lifetime is zero, the preference value MUST be set to (00) by the sender..." */
 206         adv.nd_ra_flags_reserved = ra->flags | (ra->lifetime_usec > 0 ? (ra->preference << 3) : 0);
 207         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 208
 209         /* MAC address is optional, either because the link does not use L2 addresses or load sharing is
 210          * desired. See RFC 4861, Section 4.2. */
 211         if (!ether_addr_is_null(&ra->mac_addr))
 212                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 213
 214         if (ra->mtu > 0)
 215                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 216
 217         LIST_FOREACH(prefix, p, ra->prefixes) {
 218                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 219
 220                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 221                                           p->lifetime_valid_usec);
 222
 223                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 224                                                p->lifetime_preferred_usec,
 225                                                lifetime_valid_usec);
 226
 227                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 228                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 229
 230                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 231         }
 232
 233         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 234                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 235                                                         rt->lifetime_usec));
 236
 237                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 238         }
 239
 240         LIST_FOREACH(prefix, p, ra->pref64_prefixes)
 241                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 242
 243         if (ra->rdnss)
 244                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 245
 246         if (ra->dnssl)
 247                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 248
 249         if (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
 250                 ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
 251                 ra->home_agent.nd_opt_home_agent_info_len = 1;
 252
 253                 /* 0 means to place the current Router Lifetime value */
 254                 if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
 255                         ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
 256
 257                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
 258         }
 259
 260         if (sendmsg(ra->fd, &msg, 0) < 0)
 261                 return -errno;
 262
 263         return 0;
 264 }
 265
 266 static int radv_process_packet(sd_radv *ra, ICMP6Packet *packet) {
 267         int r;
 268
 269         assert(ra);
 270         assert(packet);
 271
 272         if (icmp6_packet_get_type(packet) != ND_ROUTER_SOLICIT)
 273                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EBADMSG), "Received ICMP6 packet with unexpected type, ignoring.");
 274
 275         _cleanup_(sd_ndisc_router_solicit_unrefp) sd_ndisc_router_solicit *rs = NULL;
 276         rs = ndisc_router_solicit_new(packet);
 277         if (!rs)
 278                 return log_oom_debug();
 279
 280         r = ndisc_router_solicit_parse(ra, rs);
 281         if (r < 0)
 282                 return r;
 283
 284         struct in6_addr src;
 285         r = sd_ndisc_router_solicit_get_sender_address(rs, &src);
 286         if (r == -ENODATA) /* null address is allowed */
 287                 return sd_radv_send(ra); /* When an unsolicited RA, we need to also update timer. */
 288         if (r < 0)
 289                 return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
 290         if (in6_addr_equal(&src, &ra->ipv6ll))
 291                 /* This should be definitely caused by a misconfiguration. If we send RA to ourself, the
 292                  * kernel complains about that. Let's ignore the packet. */
 293                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EADDRINUSE), "Received RS from the same interface, ignoring.");
 294
 295         r = radv_send_router(ra, &src);
 296         if (r < 0)
 297                 return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
 298
 299         log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
 300         return 0;
 301 }
 302
 303 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 304         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
 305         sd_radv *ra = ASSERT_PTR(userdata);
 306         int r;
 307
 308         assert(fd >= 0);
 309
 310         r = icmp6_packet_receive(fd, &packet);
 311         if (r < 0) {
 312                 log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
 313                 return 0;
 314         }
 315
 316         (void) radv_process_packet(ra, packet);
 317         return 0;
 318 }
 319
 320 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 321         sd_radv *ra = ASSERT_PTR(userdata);
 322
 323         if (sd_radv_send(ra) < 0)
 324                 (void) sd_radv_stop(ra);
 325
 326         return 0;
 327 }
 328
 329 int sd_radv_send(sd_radv *ra) {
 330         usec_t min_timeout, max_timeout, time_now, timeout;
 331         int r;
 332
 333         assert_return(ra, -EINVAL);
 334         assert_return(ra->event, -EINVAL);
 335         assert_return(sd_radv_is_running(ra), -EINVAL);
 336         assert(router_lifetime_is_valid(ra->lifetime_usec));
 337
 338         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 339         if (r < 0)
 340                 return r;
 341
 342         r = radv_send_router(ra, NULL);
 343         if (r < 0)
 344                 return log_radv_errno(ra, r, "Unable to send Router Advertisement: %m");
 345
 346         ra->ra_sent++;
 347
 348         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 349         if (ra->ra_sent <= RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 350                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 351         else
 352                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 353
 354         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 355          * so lower the interval here */
 356         if (ra->lifetime_usec > 0)
 357                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 358
 359         if (max_timeout >= 9 * USEC_PER_SEC)
 360                 min_timeout = max_timeout / 3;
 361         else
 362                 min_timeout = max_timeout * 3 / 4;
 363
 364         /* RFC 4861, Section 6.2.1.
 365          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 366          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 367         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 368         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 369         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 370         assert(min_timeout <= max_timeout * 3 / 4);
 371
 372         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 373         log_radv(ra, "Sent unsolicited Router Advertisement. Next advertisement will be in %s.",
 374                  FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 375
 376         return event_reset_time(
 377                         ra->event, &ra->timeout_event_source,
 378                         CLOCK_BOOTTIME,
 379                         usec_add(time_now, timeout), MSEC_PER_SEC,
 380                         radv_timeout, ra,
 381                         ra->event_priority, "radv-timeout", true);
 382 }
 383
 384 int sd_radv_stop(sd_radv *ra) {
 385         int r;
 386
 387         if (!ra)
 388                 return 0;
 389
 390         if (ra->state == RADV_STATE_IDLE)
 391                 return 0;
 392
 393         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 394
 395         /* RFC 4861, Section 6.2.5:
 396          * the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
 397          * multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
 398         r = radv_send_router_on_stop(ra);
 399         if (r < 0)
 400                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
 401
 402         radv_reset(ra);
 403         ra->fd = safe_close(ra->fd);
 404         ra->state = RADV_STATE_IDLE;
 405
 406         return 0;
 407 }
 408
 409 static int radv_setup_recv_event(sd_radv *ra) {
 410         int r;
 411
 412         assert(ra);
 413         assert(ra->event);
 414         assert(ra->ifindex > 0);
 415
 416         _cleanup_close_ int fd = -EBADF;
 417         fd = icmp6_bind(ra->ifindex, /* is_router = */ true);
 418         if (fd < 0)
 419                 return fd;
 420
 421         _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
 422         r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
 423         if (r < 0)
 424                 return r;
 425
 426         r = sd_event_source_set_priority(s, ra->event_priority);
 427         if (r < 0)
 428                 return r;
 429
 430         (void) sd_event_source_set_description(s, "radv-receive-message");
 431
 432         ra->fd = TAKE_FD(fd);
 433         ra->recv_event_source = TAKE_PTR(s);
 434         return 0;
 435 }
 436
 437 int sd_radv_start(sd_radv *ra) {
 438         int r;
 439
 440         assert_return(ra, -EINVAL);
 441         assert_return(ra->event, -EINVAL);
 442         assert_return(ra->ifindex > 0, -EINVAL);
 443
 444         if (ra->state != RADV_STATE_IDLE)
 445                 return 0;
 446
 447         r = radv_setup_recv_event(ra);
 448         if (r < 0)
 449                 goto fail;
 450
 451         r = event_reset_time(ra->event, &ra->timeout_event_source,
 452                              CLOCK_BOOTTIME,
 453                              0, 0,
 454                              radv_timeout, ra,
 455                              ra->event_priority, "radv-timeout", true);
 456         if (r < 0)
 457                 goto fail;
 458
 459         ra->state = RADV_STATE_ADVERTISING;
 460
 461         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 462
 463         return 0;
 464
 465  fail:
 466         radv_reset(ra);
 467
 468         return r;
 469 }
 470
 471 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 472         assert_return(ra, -EINVAL);
 473         assert_return(ifindex > 0, -EINVAL);
 474
 475         if (ra->state != RADV_STATE_IDLE)
 476                 return -EBUSY;
 477
 478         ra->ifindex = ifindex;
 479
 480         return 0;
 481 }
 482
 483 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 484         assert_return(ra, -EINVAL);
 485         assert_return(ifname, -EINVAL);
 486
 487         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 488                 return -EINVAL;
 489
 490         return free_and_strdup(&ra->ifname, ifname);
 491 }
 492
 493 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 494         int r;
 495
 496         assert_return(ra, -EINVAL);
 497
 498         r = get_ifname(ra->ifindex, &ra->ifname);
 499         if (r < 0)
 500                 return r;
 501
 502         if (ret)
 503                 *ret = ra->ifname;
 504
 505         return 0;
 506 }
 507
 508 int sd_radv_set_link_local_address(sd_radv *ra, const struct in6_addr *addr) {
 509         assert_return(ra, -EINVAL);
 510         assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);
 511
 512         if (addr)
 513                 ra->ipv6ll = *addr;
 514         else
 515                 zero(ra->ipv6ll);
 516
 517         return 0;
 518 }
 519
 520 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 521         assert_return(ra, -EINVAL);
 522
 523         if (ra->state != RADV_STATE_IDLE)
 524                 return -EBUSY;
 525
 526         if (mac_addr)
 527                 ra->mac_addr = *mac_addr;
 528         else
 529                 zero(ra->mac_addr);
 530
 531         return 0;
 532 }
 533
 534 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 535         assert_return(ra, -EINVAL);
 536         assert_return(mtu >= 1280, -EINVAL);
 537
 538         ra->mtu = mtu;
 539
 540         return 0;
 541 }
 542
 543 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 544         assert_return(ra, -EINVAL);
 545
 546         ra->hop_limit = hop_limit;
 547         return 0;
 548 }
 549
 550 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 551         assert_return(ra, -EINVAL);
 552
 553         ra->retransmit_usec = usec;
 554         return 0;
 555 }
 556
 557 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 558         assert_return(ra, -EINVAL);
 559
 560         if (!router_lifetime_is_valid(usec))
 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, uint8_t 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         ra->preference = preference;
 589         return 0;
 590 }
 591
 592 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 593         assert_return(ra, -EINVAL);
 594
 595         if (ra->state != RADV_STATE_IDLE)
 596                 return -EBUSY;
 597
 598         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 599
 600         return 0;
 601 }
 602
 603 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 604         assert_return(ra, -EINVAL);
 605
 606         if (ra->state != RADV_STATE_IDLE)
 607                 return -EBUSY;
 608
 609         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 610
 611         return 0;
 612 }
 613
 614 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 615         assert_return(ra, -EINVAL);
 616
 617         if (ra->state != RADV_STATE_IDLE)
 618                 return -EBUSY;
 619
 620         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 621                 return -EINVAL;
 622
 623         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 624         return 0;
 625 }
 626
 627 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 628         sd_radv_prefix *found = NULL;
 629         int r;
 630
 631         assert_return(ra, -EINVAL);
 632         assert_return(p, -EINVAL);
 633
 634         /* Refuse prefixes that don't have a prefix set */
 635         if (in6_addr_is_null(&p->opt.in6_addr))
 636                 return -ENOEXEC;
 637
 638         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 639
 640         LIST_FOREACH(prefix, cur, ra->prefixes) {
 641                 r = in_addr_prefix_intersect(AF_INET6,
 642                                              (const union in_addr_union*) &cur->opt.in6_addr,
 643                                              cur->opt.prefixlen,
 644                                              (const union in_addr_union*) &p->opt.in6_addr,
 645                                              p->opt.prefixlen);
 646                 if (r < 0)
 647                         return r;
 648                 if (r == 0)
 649                         continue;
 650
 651                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 652                         found = cur;
 653                         break;
 654                 }
 655
 656                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 657                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 658                                       addr_p,
 659                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 660         }
 661
 662         if (found) {
 663                 /* p and cur may be equivalent. First increment the reference counter. */
 664                 sd_radv_prefix_ref(p);
 665
 666                 /* Then, remove the old entry. */
 667                 LIST_REMOVE(prefix, ra->prefixes, found);
 668                 sd_radv_prefix_unref(found);
 669
 670                 /* Finally, add the new entry. */
 671                 LIST_APPEND(prefix, ra->prefixes, p);
 672
 673                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 674                          addr_p,
 675                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 676                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 677         } else {
 678                 /* The prefix is new. Let's simply add it. */
 679
 680                 sd_radv_prefix_ref(p);
 681                 LIST_APPEND(prefix, ra->prefixes, p);
 682                 ra->n_prefixes++;
 683
 684                 log_radv(ra, "Added prefix %s", addr_p);
 685         }
 686
 687         if (ra->state == RADV_STATE_IDLE)
 688                 return 0;
 689
 690         if (ra->ra_sent == 0)
 691                 return 0;
 692
 693         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 694         r = radv_send_router(ra, NULL);
 695         if (r < 0)
 696                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 697         else
 698                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 699
 700         return 0;
 701 }
 702
 703 void sd_radv_remove_prefix(
 704                 sd_radv *ra,
 705                 const struct in6_addr *prefix,
 706                 unsigned char prefixlen) {
 707
 708         if (!ra)
 709                 return;
 710
 711         if (!prefix)
 712                 return;
 713
 714         LIST_FOREACH(prefix, cur, ra->prefixes) {
 715                 if (prefixlen != cur->opt.prefixlen)
 716                         continue;
 717
 718                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 719                         continue;
 720
 721                 LIST_REMOVE(prefix, ra->prefixes, cur);
 722                 ra->n_prefixes--;
 723                 sd_radv_prefix_unref(cur);
 724                 return;
 725         }
 726 }
 727
 728 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 729         sd_radv_route_prefix *found = NULL;
 730         int r;
 731
 732         assert_return(ra, -EINVAL);
 733         assert_return(p, -EINVAL);
 734
 735         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 736
 737         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 738                 r = in_addr_prefix_intersect(AF_INET6,
 739                                              (const union in_addr_union*) &cur->opt.in6_addr,
 740                                              cur->opt.prefixlen,
 741                                              (const union in_addr_union*) &p->opt.in6_addr,
 742                                              p->opt.prefixlen);
 743                 if (r < 0)
 744                         return r;
 745                 if (r == 0)
 746                         continue;
 747
 748                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 749                         found = cur;
 750                         break;
 751                 }
 752
 753                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 754                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 755                                       addr_p,
 756                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 757         }
 758
 759         if (found) {
 760                 /* p and cur may be equivalent. First increment the reference counter. */
 761                 sd_radv_route_prefix_ref(p);
 762
 763                 /* Then, remove the old entry. */
 764                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 765                 sd_radv_route_prefix_unref(found);
 766
 767                 /* Finally, add the new entry. */
 768                 LIST_APPEND(prefix, ra->route_prefixes, p);
 769
 770                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 771                          strna(addr_p),
 772                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 773         } else {
 774                 /* The route prefix is new. Let's simply add it. */
 775
 776                 sd_radv_route_prefix_ref(p);
 777                 LIST_APPEND(prefix, ra->route_prefixes, p);
 778                 ra->n_route_prefixes++;
 779
 780                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 781         }
 782
 783         if (ra->state == RADV_STATE_IDLE)
 784                 return 0;
 785
 786         if (ra->ra_sent == 0)
 787                 return 0;
 788
 789         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 790         r = radv_send_router(ra, NULL);
 791         if (r < 0)
 792                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 793                                strna(addr_p));
 794         else
 795                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 796
 797         return 0;
 798 }
 799
 800 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 801         sd_radv_pref64_prefix *found = NULL;
 802         int r;
 803
 804         assert_return(ra, -EINVAL);
 805         assert_return(p, -EINVAL);
 806
 807         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 808
 809         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 810                 r = in_addr_prefix_intersect(AF_INET6,
 811                                              (const union in_addr_union*) &cur->in6_addr,
 812                                              cur->prefixlen,
 813                                              (const union in_addr_union*) &p->in6_addr,
 814                                              p->prefixlen);
 815                 if (r < 0)
 816                         return r;
 817                 if (r == 0)
 818                         continue;
 819
 820                 if (cur->prefixlen == p->prefixlen) {
 821                         found = cur;
 822                         break;
 823                 }
 824
 825                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 826                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 827                                       addr_p,
 828                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 829         }
 830
 831         if (found) {
 832                 /* p and cur may be equivalent. First increment the reference counter. */
 833                 sd_radv_pref64_prefix_ref(p);
 834
 835                 /* Then, remove the old entry. */
 836                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 837                 sd_radv_pref64_prefix_unref(found);
 838
 839                 /* Finally, add the new entry. */
 840                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 841
 842                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 843                          strna(addr_p),
 844                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 845         } else {
 846                 /* The route prefix is new. Let's simply add it. */
 847
 848                 sd_radv_pref64_prefix_ref(p);
 849                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 850                 ra->n_pref64_prefixes++;
 851
 852                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 853         }
 854
 855         if (ra->state == RADV_STATE_IDLE)
 856                 return 0;
 857
 858         if (ra->ra_sent == 0)
 859                 return 0;
 860
 861         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 862         r = radv_send_router(ra, NULL);
 863         if (r < 0)
 864                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 865                                strna(addr_p));
 866         else
 867                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 868
 869         return 0;
 870 }
 871
 872 int sd_radv_set_rdnss(
 873                 sd_radv *ra,
 874                 uint64_t lifetime_usec,
 875                 const struct in6_addr *dns,
 876                 size_t n_dns) {
 877
 878         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 879         size_t len;
 880
 881         assert_return(ra, -EINVAL);
 882         assert_return(n_dns < 128, -EINVAL);
 883
 884         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 885                 return -EINVAL;
 886
 887         if (!dns || n_dns == 0) {
 888                 ra->rdnss = mfree(ra->rdnss);
 889                 ra->n_rdnss = 0;
 890
 891                 return 0;
 892         }
 893
 894         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 895
 896         opt_rdnss = malloc0(len);
 897         if (!opt_rdnss)
 898                 return -ENOMEM;
 899
 900         opt_rdnss->type = RADV_OPT_RDNSS;
 901         opt_rdnss->length = len / 8;
 902         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 903
 904         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 905
 906         free_and_replace(ra->rdnss, opt_rdnss);
 907
 908         ra->n_rdnss = n_dns;
 909
 910         return 0;
 911 }
 912
 913 int sd_radv_set_dnssl(
 914                 sd_radv *ra,
 915                 uint64_t lifetime_usec,
 916                 char **search_list) {
 917
 918         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 919         size_t len = 0;
 920         uint8_t *p;
 921
 922         assert_return(ra, -EINVAL);
 923
 924         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 925                 return -EINVAL;
 926
 927         if (strv_isempty(search_list)) {
 928                 ra->dnssl = mfree(ra->dnssl);
 929                 return 0;
 930         }
 931
 932         STRV_FOREACH(s, search_list)
 933                 len += strlen(*s) + 2;
 934
 935         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 936
 937         opt_dnssl = malloc0(len);
 938         if (!opt_dnssl)
 939                 return -ENOMEM;
 940
 941         opt_dnssl->type = RADV_OPT_DNSSL;
 942         opt_dnssl->length = len / 8;
 943         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 944
 945         p = (uint8_t *)(opt_dnssl + 1);
 946         len -= sizeof(struct sd_radv_opt_dns);
 947
 948         STRV_FOREACH(s, search_list) {
 949                 int r;
 950
 951                 r = dns_name_to_wire_format(*s, p, len, false);
 952                 if (r < 0)
 953                         return r;
 954
 955                 if (len < (size_t)r)
 956                         return -ENOBUFS;
 957
 958                 p += r;
 959                 len -= r;
 960         }
 961
 962         free_and_replace(ra->dnssl, opt_dnssl);
 963
 964         return 0;
 965 }
 966
 967 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 968         sd_radv_prefix *p;
 969
 970         assert_return(ret, -EINVAL);
 971
 972         p = new(sd_radv_prefix, 1);
 973         if (!p)
 974                 return -ENOMEM;
 975
 976         *p = (sd_radv_prefix) {
 977                 .n_ref = 1,
 978
 979                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 980                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 981                 .opt.prefixlen = 64,
 982
 983                 /* RFC 4861, Section 6.2.1 */
 984                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 985
 986                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 987                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 988                 .valid_until = USEC_INFINITY,
 989                 .preferred_until = USEC_INFINITY,
 990         };
 991
 992         *ret = p;
 993         return 0;
 994 }
 995
 996 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
 997
 998 int sd_radv_prefix_set_prefix(
 999                 sd_radv_prefix *p,
1000                 const struct in6_addr *in6_addr,
1001                 unsigned char prefixlen) {
1002
1003         assert_return(p, -EINVAL);
1004         assert_return(in6_addr, -EINVAL);
1005
1006         if (prefixlen < 3 || prefixlen > 128)
1007                 return -EINVAL;
1008
1009         if (prefixlen > 64)
1010                 /* unusual but allowed, log it */
1011                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
1012
1013         p->opt.in6_addr = *in6_addr;
1014         p->opt.prefixlen = prefixlen;
1015
1016         return 0;
1017 }
1018
1019 int sd_radv_prefix_get_prefix(
1020                 sd_radv_prefix *p,
1021                 struct in6_addr *ret_in6_addr,
1022                 unsigned char *ret_prefixlen) {
1023
1024         assert_return(p, -EINVAL);
1025         assert_return(ret_in6_addr, -EINVAL);
1026         assert_return(ret_prefixlen, -EINVAL);
1027
1028         *ret_in6_addr = p->opt.in6_addr;
1029         *ret_prefixlen = p->opt.prefixlen;
1030
1031         return 0;
1032 }
1033
1034 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1035         assert_return(p, -EINVAL);
1036
1037         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1038
1039         return 0;
1040 }
1041
1042 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1043         assert_return(p, -EINVAL);
1044
1045         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1046
1047         return 0;
1048 }
1049
1050 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1051         assert_return(p, -EINVAL);
1052
1053         p->lifetime_valid_usec = lifetime_usec;
1054         p->valid_until = valid_until;
1055
1056         return 0;
1057 }
1058
1059 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1060         assert_return(p, -EINVAL);
1061
1062         p->lifetime_preferred_usec = lifetime_usec;
1063         p->preferred_until = valid_until;
1064
1065         return 0;
1066 }
1067
1068 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1069         sd_radv_route_prefix *p;
1070
1071         assert_return(ret, -EINVAL);
1072
1073         p = new(sd_radv_route_prefix, 1);
1074         if (!p)
1075                 return -ENOMEM;
1076
1077         *p = (sd_radv_route_prefix) {
1078                 .n_ref = 1,
1079
1080                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1081                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1082                 .opt.prefixlen = 64,
1083
1084                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1085                 .valid_until = USEC_INFINITY,
1086         };
1087
1088         *ret = p;
1089         return 0;
1090 }
1091
1092 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1093
1094 int sd_radv_route_prefix_set_prefix(
1095                 sd_radv_route_prefix *p,
1096                 const struct in6_addr *in6_addr,
1097                 unsigned char prefixlen) {
1098
1099         assert_return(p, -EINVAL);
1100         assert_return(in6_addr, -EINVAL);
1101
1102         if (prefixlen > 128)
1103                 return -EINVAL;
1104
1105         if (prefixlen > 64)
1106                 /* unusual but allowed, log it */
1107                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1108
1109         p->opt.in6_addr = *in6_addr;
1110         p->opt.prefixlen = prefixlen;
1111
1112         return 0;
1113 }
1114
1115 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1116         assert_return(p, -EINVAL);
1117
1118         p->lifetime_usec = lifetime_usec;
1119         p->valid_until = valid_until;
1120
1121         return 0;
1122 }
1123
1124 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1125         sd_radv_pref64_prefix *p;
1126
1127         assert_return(ret, -EINVAL);
1128
1129         p = new(sd_radv_pref64_prefix, 1);
1130         if (!p)
1131                 return -ENOMEM;
1132
1133         *p = (sd_radv_pref64_prefix) {
1134                 .n_ref = 1,
1135
1136                 .opt.type = RADV_OPT_PREF64,
1137                 .opt.length = 2,
1138         };
1139
1140         *ret = p;
1141         return 0;
1142 }
1143
1144 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1145
1146 int sd_radv_pref64_prefix_set_prefix(
1147                 sd_radv_pref64_prefix *p,
1148                 const struct in6_addr *prefix,
1149                 uint8_t prefixlen,
1150                 uint64_t lifetime_usec) {
1151
1152         uint16_t pref64_lifetime;
1153         uint8_t prefixlen_code;
1154         int r;
1155
1156         assert_return(p, -EINVAL);
1157         assert_return(prefix, -EINVAL);
1158
1159         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1160         if (r < 0)
1161                 return log_radv_errno(NULL, r,
1162                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1163
1164         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1165                 return -EINVAL;
1166
1167         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1168         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1169         pref64_lifetime |= prefixlen_code;
1170
1171         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1172         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1173
1174         p->in6_addr = *prefix;
1175         p->prefixlen = prefixlen;
1176
1177         return 0;
1178 }