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 == -ENODATA) /* null address is allowed */
 285                 return sd_radv_send(ra); /* When an unsolicited RA, we need to also update timer. */
 286         if (r < 0)
 287                 return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
 288         if (in6_addr_equal(&src, &ra->ipv6ll))
 289                 /* This should be definitely caused by a misconfiguration. If we send RA to ourself, the
 290                  * kernel complains about that. Let's ignore the packet. */
 291                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EADDRINUSE), "Received RS from the same interface, ignoring.");
 292
 293         r = radv_send_router(ra, &src);
 294         if (r < 0)
 295                 return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
 296
 297         log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
 298         return 0;
 299 }
 300
 301 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 302         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
 303         sd_radv *ra = ASSERT_PTR(userdata);
 304         int r;
 305
 306         assert(fd >= 0);
 307
 308         r = icmp6_packet_receive(fd, &packet);
 309         if (r < 0) {
 310                 log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
 311                 return 0;
 312         }
 313
 314         (void) radv_process_packet(ra, packet);
 315         return 0;
 316 }
 317
 318 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 319         sd_radv *ra = ASSERT_PTR(userdata);
 320
 321         if (sd_radv_send(ra) < 0)
 322                 (void) sd_radv_stop(ra);
 323
 324         return 0;
 325 }
 326
 327 int sd_radv_send(sd_radv *ra) {
 328         usec_t min_timeout, max_timeout, time_now, timeout;
 329         int r;
 330
 331         assert_return(ra, -EINVAL);
 332         assert_return(ra->event, -EINVAL);
 333         assert_return(sd_radv_is_running(ra), -EINVAL);
 334         assert(router_lifetime_is_valid(ra->lifetime_usec));
 335
 336         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 337         if (r < 0)
 338                 return r;
 339
 340         r = radv_send_router(ra, NULL);
 341         if (r < 0)
 342                 return log_radv_errno(ra, r, "Unable to send Router Advertisement: %m");
 343
 344         ra->ra_sent++;
 345
 346         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 347         if (ra->ra_sent <= RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 348                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 349         else
 350                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 351
 352         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 353          * so lower the interval here */
 354         if (ra->lifetime_usec > 0)
 355                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 356
 357         if (max_timeout >= 9 * USEC_PER_SEC)
 358                 min_timeout = max_timeout / 3;
 359         else
 360                 min_timeout = max_timeout * 3 / 4;
 361
 362         /* RFC 4861, Section 6.2.1.
 363          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 364          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 365         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 366         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 367         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 368         assert(min_timeout <= max_timeout * 3 / 4);
 369
 370         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 371         log_radv(ra, "Sent unsolicited Router Advertisement. Next advertisement will be in %s.",
 372                  FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 373
 374         return event_reset_time(
 375                         ra->event, &ra->timeout_event_source,
 376                         CLOCK_BOOTTIME,
 377                         usec_add(time_now, timeout), MSEC_PER_SEC,
 378                         radv_timeout, ra,
 379                         ra->event_priority, "radv-timeout", true);
 380 }
 381
 382 int sd_radv_stop(sd_radv *ra) {
 383         int r;
 384
 385         if (!ra)
 386                 return 0;
 387
 388         if (ra->state == RADV_STATE_IDLE)
 389                 return 0;
 390
 391         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 392
 393         /* RFC 4861, Section 6.2.5:
 394          * the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
 395          * multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
 396         r = radv_send_router_on_stop(ra);
 397         if (r < 0)
 398                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
 399
 400         radv_reset(ra);
 401         ra->fd = safe_close(ra->fd);
 402         ra->state = RADV_STATE_IDLE;
 403
 404         return 0;
 405 }
 406
 407 static int radv_setup_recv_event(sd_radv *ra) {
 408         int r;
 409
 410         assert(ra);
 411         assert(ra->event);
 412         assert(ra->ifindex > 0);
 413
 414         _cleanup_close_ int fd = -EBADF;
 415         fd = icmp6_bind(ra->ifindex, /* is_router = */ true);
 416         if (fd < 0)
 417                 return fd;
 418
 419         _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
 420         r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
 421         if (r < 0)
 422                 return r;
 423
 424         r = sd_event_source_set_priority(s, ra->event_priority);
 425         if (r < 0)
 426                 return r;
 427
 428         (void) sd_event_source_set_description(s, "radv-receive-message");
 429
 430         ra->fd = TAKE_FD(fd);
 431         ra->recv_event_source = TAKE_PTR(s);
 432         return 0;
 433 }
 434
 435 int sd_radv_start(sd_radv *ra) {
 436         int r;
 437
 438         assert_return(ra, -EINVAL);
 439         assert_return(ra->event, -EINVAL);
 440         assert_return(ra->ifindex > 0, -EINVAL);
 441
 442         if (ra->state != RADV_STATE_IDLE)
 443                 return 0;
 444
 445         r = radv_setup_recv_event(ra);
 446         if (r < 0)
 447                 goto fail;
 448
 449         r = event_reset_time(ra->event, &ra->timeout_event_source,
 450                              CLOCK_BOOTTIME,
 451                              0, 0,
 452                              radv_timeout, ra,
 453                              ra->event_priority, "radv-timeout", true);
 454         if (r < 0)
 455                 goto fail;
 456
 457         ra->state = RADV_STATE_ADVERTISING;
 458
 459         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 460
 461         return 0;
 462
 463  fail:
 464         radv_reset(ra);
 465
 466         return r;
 467 }
 468
 469 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 470         assert_return(ra, -EINVAL);
 471         assert_return(ifindex > 0, -EINVAL);
 472
 473         if (ra->state != RADV_STATE_IDLE)
 474                 return -EBUSY;
 475
 476         ra->ifindex = ifindex;
 477
 478         return 0;
 479 }
 480
 481 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 482         assert_return(ra, -EINVAL);
 483         assert_return(ifname, -EINVAL);
 484
 485         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 486                 return -EINVAL;
 487
 488         return free_and_strdup(&ra->ifname, ifname);
 489 }
 490
 491 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 492         int r;
 493
 494         assert_return(ra, -EINVAL);
 495
 496         r = get_ifname(ra->ifindex, &ra->ifname);
 497         if (r < 0)
 498                 return r;
 499
 500         if (ret)
 501                 *ret = ra->ifname;
 502
 503         return 0;
 504 }
 505
 506 int sd_radv_set_link_local_address(sd_radv *ra, const struct in6_addr *addr) {
 507         assert_return(ra, -EINVAL);
 508         assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);
 509
 510         if (addr)
 511                 ra->ipv6ll = *addr;
 512         else
 513                 zero(ra->ipv6ll);
 514
 515         return 0;
 516 }
 517
 518 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 519         assert_return(ra, -EINVAL);
 520
 521         if (ra->state != RADV_STATE_IDLE)
 522                 return -EBUSY;
 523
 524         if (mac_addr)
 525                 ra->mac_addr = *mac_addr;
 526         else
 527                 zero(ra->mac_addr);
 528
 529         return 0;
 530 }
 531
 532 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 533         assert_return(ra, -EINVAL);
 534         assert_return(mtu >= 1280, -EINVAL);
 535
 536         ra->mtu = mtu;
 537
 538         return 0;
 539 }
 540
 541 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 542         assert_return(ra, -EINVAL);
 543
 544         if (ra->state != RADV_STATE_IDLE)
 545                 return -EBUSY;
 546
 547         ra->hop_limit = hop_limit;
 548
 549         return 0;
 550 }
 551
 552 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 553         assert_return(ra, -EINVAL);
 554
 555         if (ra->state != RADV_STATE_IDLE)
 556                 return -EBUSY;
 557
 558         if (usec > RADV_MAX_RETRANSMIT_USEC)
 559                 return -EINVAL;
 560
 561         ra->retransmit_usec = usec;
 562         return 0;
 563 }
 564
 565 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 566         assert_return(ra, -EINVAL);
 567
 568         if (ra->state != RADV_STATE_IDLE)
 569                 return -EBUSY;
 570
 571         if (!router_lifetime_is_valid(usec))
 572                 return -EINVAL;
 573
 574         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 575          * to (00) by the sender..." */
 576         if (usec == 0 &&
 577             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 578                 return -EINVAL;
 579
 580         ra->lifetime_usec = usec;
 581         return 0;
 582 }
 583
 584 int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 585         assert_return(ra, -EINVAL);
 586
 587         if (ra->state != RADV_STATE_IDLE)
 588                 return -EBUSY;
 589
 590         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 591
 592         return 0;
 593 }
 594
 595 int sd_radv_set_other_information(sd_radv *ra, int other) {
 596         assert_return(ra, -EINVAL);
 597
 598         if (ra->state != RADV_STATE_IDLE)
 599                 return -EBUSY;
 600
 601         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 602
 603         return 0;
 604 }
 605
 606 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 607         assert_return(ra, -EINVAL);
 608         assert_return(IN_SET(preference,
 609                              SD_NDISC_PREFERENCE_LOW,
 610                              SD_NDISC_PREFERENCE_MEDIUM,
 611                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 612
 613         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 614          * to (00) by the sender..." */
 615         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 616                 return -EINVAL;
 617
 618         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 619
 620         return 0;
 621 }
 622
 623 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 624         assert_return(ra, -EINVAL);
 625
 626         if (ra->state != RADV_STATE_IDLE)
 627                 return -EBUSY;
 628
 629         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 630
 631         return 0;
 632 }
 633
 634 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 635         assert_return(ra, -EINVAL);
 636
 637         if (ra->state != RADV_STATE_IDLE)
 638                 return -EBUSY;
 639
 640         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 641
 642         return 0;
 643 }
 644
 645 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 646         assert_return(ra, -EINVAL);
 647
 648         if (ra->state != RADV_STATE_IDLE)
 649                 return -EBUSY;
 650
 651         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 652                 return -EINVAL;
 653
 654         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 655         return 0;
 656 }
 657
 658 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 659         sd_radv_prefix *found = NULL;
 660         int r;
 661
 662         assert_return(ra, -EINVAL);
 663         assert_return(p, -EINVAL);
 664
 665         /* Refuse prefixes that don't have a prefix set */
 666         if (in6_addr_is_null(&p->opt.in6_addr))
 667                 return -ENOEXEC;
 668
 669         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 670
 671         LIST_FOREACH(prefix, cur, ra->prefixes) {
 672                 r = in_addr_prefix_intersect(AF_INET6,
 673                                              (const union in_addr_union*) &cur->opt.in6_addr,
 674                                              cur->opt.prefixlen,
 675                                              (const union in_addr_union*) &p->opt.in6_addr,
 676                                              p->opt.prefixlen);
 677                 if (r < 0)
 678                         return r;
 679                 if (r == 0)
 680                         continue;
 681
 682                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 683                         found = cur;
 684                         break;
 685                 }
 686
 687                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 688                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 689                                       addr_p,
 690                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 691         }
 692
 693         if (found) {
 694                 /* p and cur may be equivalent. First increment the reference counter. */
 695                 sd_radv_prefix_ref(p);
 696
 697                 /* Then, remove the old entry. */
 698                 LIST_REMOVE(prefix, ra->prefixes, found);
 699                 sd_radv_prefix_unref(found);
 700
 701                 /* Finally, add the new entry. */
 702                 LIST_APPEND(prefix, ra->prefixes, p);
 703
 704                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 705                          addr_p,
 706                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 707                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 708         } else {
 709                 /* The prefix is new. Let's simply add it. */
 710
 711                 sd_radv_prefix_ref(p);
 712                 LIST_APPEND(prefix, ra->prefixes, p);
 713                 ra->n_prefixes++;
 714
 715                 log_radv(ra, "Added prefix %s", addr_p);
 716         }
 717
 718         if (ra->state == RADV_STATE_IDLE)
 719                 return 0;
 720
 721         if (ra->ra_sent == 0)
 722                 return 0;
 723
 724         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 725         r = radv_send_router(ra, NULL);
 726         if (r < 0)
 727                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 728         else
 729                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 730
 731         return 0;
 732 }
 733
 734 void sd_radv_remove_prefix(
 735                 sd_radv *ra,
 736                 const struct in6_addr *prefix,
 737                 unsigned char prefixlen) {
 738
 739         if (!ra)
 740                 return;
 741
 742         if (!prefix)
 743                 return;
 744
 745         LIST_FOREACH(prefix, cur, ra->prefixes) {
 746                 if (prefixlen != cur->opt.prefixlen)
 747                         continue;
 748
 749                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 750                         continue;
 751
 752                 LIST_REMOVE(prefix, ra->prefixes, cur);
 753                 ra->n_prefixes--;
 754                 sd_radv_prefix_unref(cur);
 755                 return;
 756         }
 757 }
 758
 759 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 760         sd_radv_route_prefix *found = NULL;
 761         int r;
 762
 763         assert_return(ra, -EINVAL);
 764         assert_return(p, -EINVAL);
 765
 766         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 767
 768         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 769                 r = in_addr_prefix_intersect(AF_INET6,
 770                                              (const union in_addr_union*) &cur->opt.in6_addr,
 771                                              cur->opt.prefixlen,
 772                                              (const union in_addr_union*) &p->opt.in6_addr,
 773                                              p->opt.prefixlen);
 774                 if (r < 0)
 775                         return r;
 776                 if (r == 0)
 777                         continue;
 778
 779                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 780                         found = cur;
 781                         break;
 782                 }
 783
 784                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 785                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 786                                       addr_p,
 787                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 788         }
 789
 790         if (found) {
 791                 /* p and cur may be equivalent. First increment the reference counter. */
 792                 sd_radv_route_prefix_ref(p);
 793
 794                 /* Then, remove the old entry. */
 795                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 796                 sd_radv_route_prefix_unref(found);
 797
 798                 /* Finally, add the new entry. */
 799                 LIST_APPEND(prefix, ra->route_prefixes, p);
 800
 801                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 802                          strna(addr_p),
 803                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 804         } else {
 805                 /* The route prefix is new. Let's simply add it. */
 806
 807                 sd_radv_route_prefix_ref(p);
 808                 LIST_APPEND(prefix, ra->route_prefixes, p);
 809                 ra->n_route_prefixes++;
 810
 811                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 812         }
 813
 814         if (ra->state == RADV_STATE_IDLE)
 815                 return 0;
 816
 817         if (ra->ra_sent == 0)
 818                 return 0;
 819
 820         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 821         r = radv_send_router(ra, NULL);
 822         if (r < 0)
 823                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 824                                strna(addr_p));
 825         else
 826                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 827
 828         return 0;
 829 }
 830
 831 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 832         sd_radv_pref64_prefix *found = NULL;
 833         int r;
 834
 835         assert_return(ra, -EINVAL);
 836         assert_return(p, -EINVAL);
 837
 838         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 839
 840         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 841                 r = in_addr_prefix_intersect(AF_INET6,
 842                                              (const union in_addr_union*) &cur->in6_addr,
 843                                              cur->prefixlen,
 844                                              (const union in_addr_union*) &p->in6_addr,
 845                                              p->prefixlen);
 846                 if (r < 0)
 847                         return r;
 848                 if (r == 0)
 849                         continue;
 850
 851                 if (cur->prefixlen == p->prefixlen) {
 852                         found = cur;
 853                         break;
 854                 }
 855
 856                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 857                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 858                                       addr_p,
 859                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 860         }
 861
 862         if (found) {
 863                 /* p and cur may be equivalent. First increment the reference counter. */
 864                 sd_radv_pref64_prefix_ref(p);
 865
 866                 /* Then, remove the old entry. */
 867                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 868                 sd_radv_pref64_prefix_unref(found);
 869
 870                 /* Finally, add the new entry. */
 871                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 872
 873                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 874                          strna(addr_p),
 875                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 876         } else {
 877                 /* The route prefix is new. Let's simply add it. */
 878
 879                 sd_radv_pref64_prefix_ref(p);
 880                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 881                 ra->n_pref64_prefixes++;
 882
 883                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 884         }
 885
 886         if (ra->state == RADV_STATE_IDLE)
 887                 return 0;
 888
 889         if (ra->ra_sent == 0)
 890                 return 0;
 891
 892         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 893         r = radv_send_router(ra, NULL);
 894         if (r < 0)
 895                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 896                                strna(addr_p));
 897         else
 898                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 899
 900         return 0;
 901 }
 902
 903 int sd_radv_set_rdnss(
 904                 sd_radv *ra,
 905                 uint64_t lifetime_usec,
 906                 const struct in6_addr *dns,
 907                 size_t n_dns) {
 908
 909         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 910         size_t len;
 911
 912         assert_return(ra, -EINVAL);
 913         assert_return(n_dns < 128, -EINVAL);
 914
 915         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 916                 return -EINVAL;
 917
 918         if (!dns || n_dns == 0) {
 919                 ra->rdnss = mfree(ra->rdnss);
 920                 ra->n_rdnss = 0;
 921
 922                 return 0;
 923         }
 924
 925         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 926
 927         opt_rdnss = malloc0(len);
 928         if (!opt_rdnss)
 929                 return -ENOMEM;
 930
 931         opt_rdnss->type = RADV_OPT_RDNSS;
 932         opt_rdnss->length = len / 8;
 933         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 934
 935         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 936
 937         free_and_replace(ra->rdnss, opt_rdnss);
 938
 939         ra->n_rdnss = n_dns;
 940
 941         return 0;
 942 }
 943
 944 int sd_radv_set_dnssl(
 945                 sd_radv *ra,
 946                 uint64_t lifetime_usec,
 947                 char **search_list) {
 948
 949         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 950         size_t len = 0;
 951         uint8_t *p;
 952
 953         assert_return(ra, -EINVAL);
 954
 955         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 956                 return -EINVAL;
 957
 958         if (strv_isempty(search_list)) {
 959                 ra->dnssl = mfree(ra->dnssl);
 960                 return 0;
 961         }
 962
 963         STRV_FOREACH(s, search_list)
 964                 len += strlen(*s) + 2;
 965
 966         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 967
 968         opt_dnssl = malloc0(len);
 969         if (!opt_dnssl)
 970                 return -ENOMEM;
 971
 972         opt_dnssl->type = RADV_OPT_DNSSL;
 973         opt_dnssl->length = len / 8;
 974         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 975
 976         p = (uint8_t *)(opt_dnssl + 1);
 977         len -= sizeof(struct sd_radv_opt_dns);
 978
 979         STRV_FOREACH(s, search_list) {
 980                 int r;
 981
 982                 r = dns_name_to_wire_format(*s, p, len, false);
 983                 if (r < 0)
 984                         return r;
 985
 986                 if (len < (size_t)r)
 987                         return -ENOBUFS;
 988
 989                 p += r;
 990                 len -= r;
 991         }
 992
 993         free_and_replace(ra->dnssl, opt_dnssl);
 994
 995         return 0;
 996 }
 997
 998 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 999         sd_radv_prefix *p;
1000
1001         assert_return(ret, -EINVAL);
1002
1003         p = new(sd_radv_prefix, 1);
1004         if (!p)
1005                 return -ENOMEM;
1006
1007         *p = (sd_radv_prefix) {
1008                 .n_ref = 1,
1009
1010                 .opt.type = ND_OPT_PREFIX_INFORMATION,
1011                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
1012                 .opt.prefixlen = 64,
1013
1014                 /* RFC 4861, Section 6.2.1 */
1015                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
1016
1017                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1018                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
1019                 .valid_until = USEC_INFINITY,
1020                 .preferred_until = USEC_INFINITY,
1021         };
1022
1023         *ret = p;
1024         return 0;
1025 }
1026
1027 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
1028
1029 int sd_radv_prefix_set_prefix(
1030                 sd_radv_prefix *p,
1031                 const struct in6_addr *in6_addr,
1032                 unsigned char prefixlen) {
1033
1034         assert_return(p, -EINVAL);
1035         assert_return(in6_addr, -EINVAL);
1036
1037         if (prefixlen < 3 || prefixlen > 128)
1038                 return -EINVAL;
1039
1040         if (prefixlen > 64)
1041                 /* unusual but allowed, log it */
1042                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
1043
1044         p->opt.in6_addr = *in6_addr;
1045         p->opt.prefixlen = prefixlen;
1046
1047         return 0;
1048 }
1049
1050 int sd_radv_prefix_get_prefix(
1051                 sd_radv_prefix *p,
1052                 struct in6_addr *ret_in6_addr,
1053                 unsigned char *ret_prefixlen) {
1054
1055         assert_return(p, -EINVAL);
1056         assert_return(ret_in6_addr, -EINVAL);
1057         assert_return(ret_prefixlen, -EINVAL);
1058
1059         *ret_in6_addr = p->opt.in6_addr;
1060         *ret_prefixlen = p->opt.prefixlen;
1061
1062         return 0;
1063 }
1064
1065 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1066         assert_return(p, -EINVAL);
1067
1068         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1069
1070         return 0;
1071 }
1072
1073 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1074         assert_return(p, -EINVAL);
1075
1076         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1077
1078         return 0;
1079 }
1080
1081 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1082         assert_return(p, -EINVAL);
1083
1084         p->lifetime_valid_usec = lifetime_usec;
1085         p->valid_until = valid_until;
1086
1087         return 0;
1088 }
1089
1090 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1091         assert_return(p, -EINVAL);
1092
1093         p->lifetime_preferred_usec = lifetime_usec;
1094         p->preferred_until = valid_until;
1095
1096         return 0;
1097 }
1098
1099 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1100         sd_radv_route_prefix *p;
1101
1102         assert_return(ret, -EINVAL);
1103
1104         p = new(sd_radv_route_prefix, 1);
1105         if (!p)
1106                 return -ENOMEM;
1107
1108         *p = (sd_radv_route_prefix) {
1109                 .n_ref = 1,
1110
1111                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1112                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1113                 .opt.prefixlen = 64,
1114
1115                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1116                 .valid_until = USEC_INFINITY,
1117         };
1118
1119         *ret = p;
1120         return 0;
1121 }
1122
1123 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1124
1125 int sd_radv_route_prefix_set_prefix(
1126                 sd_radv_route_prefix *p,
1127                 const struct in6_addr *in6_addr,
1128                 unsigned char prefixlen) {
1129
1130         assert_return(p, -EINVAL);
1131         assert_return(in6_addr, -EINVAL);
1132
1133         if (prefixlen > 128)
1134                 return -EINVAL;
1135
1136         if (prefixlen > 64)
1137                 /* unusual but allowed, log it */
1138                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1139
1140         p->opt.in6_addr = *in6_addr;
1141         p->opt.prefixlen = prefixlen;
1142
1143         return 0;
1144 }
1145
1146 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1147         assert_return(p, -EINVAL);
1148
1149         p->lifetime_usec = lifetime_usec;
1150         p->valid_until = valid_until;
1151
1152         return 0;
1153 }
1154
1155 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1156         sd_radv_pref64_prefix *p;
1157
1158         assert_return(ret, -EINVAL);
1159
1160         p = new(sd_radv_pref64_prefix, 1);
1161         if (!p)
1162                 return -ENOMEM;
1163
1164         *p = (sd_radv_pref64_prefix) {
1165                 .n_ref = 1,
1166
1167                 .opt.type = RADV_OPT_PREF64,
1168                 .opt.length = 2,
1169         };
1170
1171         *ret = p;
1172         return 0;
1173 }
1174
1175 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1176
1177 int sd_radv_pref64_prefix_set_prefix(
1178                 sd_radv_pref64_prefix *p,
1179                 const struct in6_addr *prefix,
1180                 uint8_t prefixlen,
1181                 uint64_t lifetime_usec) {
1182
1183         uint16_t pref64_lifetime;
1184         uint8_t prefixlen_code;
1185         int r;
1186
1187         assert_return(p, -EINVAL);
1188         assert_return(prefix, -EINVAL);
1189
1190         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1191         if (r < 0)
1192                 return log_radv_errno(NULL, r,
1193                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1194
1195         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1196                 return -EINVAL;
1197
1198         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1199         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1200         pref64_lifetime |= prefixlen_code;
1201
1202         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1203         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1204
1205         p->in6_addr = *prefix;
1206         p->prefixlen = prefixlen;
1207
1208         return 0;
1209 }