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(sd_radv *ra, const struct in6_addr *dst, usec_t lifetime_usec) {
 133         assert(ra);
 134         assert(router_lifetime_is_valid(lifetime_usec));
 135
 136         struct sockaddr_in6 dst_addr = {
 137                 .sin6_family = AF_INET6,
 138                 .sin6_addr = IN6_ADDR_ALL_NODES_MULTICAST,
 139         };
 140         struct nd_router_advert adv = {
 141                 .nd_ra_type = ND_ROUTER_ADVERT,
 142                 .nd_ra_router_lifetime = usec_to_be16_sec(lifetime_usec),
 143                 .nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec),
 144         };
 145         struct {
 146                 struct nd_opt_hdr opthdr;
 147                 struct ether_addr slladdr;
 148         } _packed_ opt_mac = {
 149                 .opthdr = {
 150                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 151                         .nd_opt_len = DIV_ROUND_UP(sizeof(struct nd_opt_hdr) + sizeof(struct ether_addr), 8),
 152                 },
 153                 .slladdr = ra->mac_addr,
 154         };
 155         struct nd_opt_mtu opt_mtu =  {
 156                 .nd_opt_mtu_type = ND_OPT_MTU,
 157                 .nd_opt_mtu_len = 1,
 158                 .nd_opt_mtu_mtu = htobe32(ra->mtu),
 159         };
 160         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, N pref64 prefixes, RDNSS,
 161          * DNSSL, and home agent. */
 162         struct iovec iov[6 + ra->n_prefixes + ra->n_route_prefixes + ra->n_pref64_prefixes];
 163         struct msghdr msg = {
 164                 .msg_name = &dst_addr,
 165                 .msg_namelen = sizeof(dst_addr),
 166                 .msg_iov = iov,
 167         };
 168         usec_t time_now;
 169         int r;
 170
 171         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 172         if (r < 0)
 173                 return r;
 174
 175         if (dst && in6_addr_is_set(dst))
 176                 dst_addr.sin6_addr = *dst;
 177
 178         /* The nd_ra_curhoplimit and nd_ra_flags_reserved fields cannot specified with nd_ra_router_lifetime
 179          * simultaneously in the structured initializer in the above. */
 180         adv.nd_ra_curhoplimit = ra->hop_limit;
 181         adv.nd_ra_flags_reserved = ra->flags;
 182         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 183
 184         /* MAC address is optional, either because the link does not use L2 addresses or load sharing is
 185          * desired. See RFC 4861, Section 4.2. */
 186         if (!ether_addr_is_null(&ra->mac_addr))
 187                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 188
 189         if (ra->mtu > 0)
 190                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 191
 192         LIST_FOREACH(prefix, p, ra->prefixes) {
 193                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 194
 195                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 196                                           p->lifetime_valid_usec);
 197
 198                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 199                                                p->lifetime_preferred_usec,
 200                                                lifetime_valid_usec);
 201
 202                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 203                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 204
 205                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 206         }
 207
 208         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 209                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 210                                                         rt->lifetime_usec));
 211
 212                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 213         }
 214
 215         LIST_FOREACH(prefix, p, ra->pref64_prefixes)
 216                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 217
 218         if (ra->rdnss)
 219                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 220
 221         if (ra->dnssl)
 222                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 223
 224         if (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
 225                 ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
 226                 ra->home_agent.nd_opt_home_agent_info_len = 1;
 227
 228                 /* 0 means to place the current Router Lifetime value */
 229                 if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
 230                         ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
 231
 232                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
 233         }
 234
 235         if (sendmsg(ra->fd, &msg, 0) < 0)
 236                 return -errno;
 237
 238         return 0;
 239 }
 240
 241 static int radv_process_packet(sd_radv *ra, ICMP6Packet *packet) {
 242         int r;
 243
 244         assert(ra);
 245         assert(packet);
 246
 247         if (icmp6_packet_get_type(packet) != ND_ROUTER_SOLICIT)
 248                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EBADMSG), "Received ICMP6 packet with unexpected type, ignoring.");
 249
 250         _cleanup_(sd_ndisc_router_solicit_unrefp) sd_ndisc_router_solicit *rs = NULL;
 251         rs = ndisc_router_solicit_new(packet);
 252         if (!rs)
 253                 return log_oom_debug();
 254
 255         r = ndisc_router_solicit_parse(ra, rs);
 256         if (r < 0)
 257                 return r;
 258
 259         struct in6_addr src = {};
 260         r = sd_ndisc_router_solicit_get_sender_address(rs, &src);
 261         if (r < 0 && r != -ENODATA) /* null address is allowed */
 262                 return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
 263
 264         r = radv_send_router(ra, &src, ra->lifetime_usec);
 265         if (r < 0)
 266                 return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
 267
 268         log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
 269         return 0;
 270 }
 271
 272 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 273         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
 274         sd_radv *ra = ASSERT_PTR(userdata);
 275         int r;
 276
 277         assert(fd >= 0);
 278
 279         r = icmp6_packet_receive(fd, &packet);
 280         if (r < 0) {
 281                 log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
 282                 return 0;
 283         }
 284
 285         (void) radv_process_packet(ra, packet);
 286         return 0;
 287 }
 288
 289 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 290         usec_t min_timeout, max_timeout, time_now, timeout;
 291         sd_radv *ra = ASSERT_PTR(userdata);
 292         int r;
 293
 294         assert(s);
 295         assert(ra->event);
 296         assert(router_lifetime_is_valid(ra->lifetime_usec));
 297
 298         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 299         if (r < 0)
 300                 goto fail;
 301
 302         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 303         if (r < 0)
 304                 log_radv_errno(ra, r, "Unable to send Router Advertisement, ignoring: %m");
 305
 306         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 307         if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 308                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 309         else
 310                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 311
 312         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 313          * so lower the interval here */
 314         if (ra->lifetime_usec > 0)
 315                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 316
 317         if (max_timeout >= 9 * USEC_PER_SEC)
 318                 min_timeout = max_timeout / 3;
 319         else
 320                 min_timeout = max_timeout * 3 / 4;
 321
 322         /* RFC 4861, Section 6.2.1.
 323          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 324          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 325         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 326         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 327         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 328         assert(min_timeout <= max_timeout * 3 / 4);
 329
 330         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 331         log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 332
 333         r = event_reset_time(ra->event, &ra->timeout_event_source,
 334                              CLOCK_BOOTTIME,
 335                              usec_add(time_now, timeout), MSEC_PER_SEC,
 336                              radv_timeout, ra,
 337                              ra->event_priority, "radv-timeout", true);
 338         if (r < 0)
 339                 goto fail;
 340
 341         ra->ra_sent++;
 342
 343         return 0;
 344
 345 fail:
 346         sd_radv_stop(ra);
 347
 348         return 0;
 349 }
 350
 351 int sd_radv_stop(sd_radv *ra) {
 352         int r;
 353
 354         if (!ra)
 355                 return 0;
 356
 357         if (ra->state == RADV_STATE_IDLE)
 358                 return 0;
 359
 360         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 361
 362         /* RFC 4861, Section 6.2.5:
 363          * the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
 364          * multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
 365         r = radv_send_router(ra, NULL, 0);
 366         if (r < 0)
 367                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
 368
 369         radv_reset(ra);
 370         ra->fd = safe_close(ra->fd);
 371         ra->state = RADV_STATE_IDLE;
 372
 373         return 0;
 374 }
 375
 376 static int radv_setup_recv_event(sd_radv *ra) {
 377         int r;
 378
 379         assert(ra);
 380         assert(ra->event);
 381         assert(ra->ifindex > 0);
 382
 383         _cleanup_close_ int fd = -EBADF;
 384         fd = icmp6_bind(ra->ifindex, /* is_router = */ true);
 385         if (fd < 0)
 386                 return fd;
 387
 388         _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
 389         r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
 390         if (r < 0)
 391                 return r;
 392
 393         r = sd_event_source_set_priority(s, ra->event_priority);
 394         if (r < 0)
 395                 return r;
 396
 397         (void) sd_event_source_set_description(s, "radv-receive-message");
 398
 399         ra->fd = TAKE_FD(fd);
 400         ra->recv_event_source = TAKE_PTR(s);
 401         return 0;
 402 }
 403
 404 int sd_radv_start(sd_radv *ra) {
 405         int r;
 406
 407         assert_return(ra, -EINVAL);
 408         assert_return(ra->event, -EINVAL);
 409         assert_return(ra->ifindex > 0, -EINVAL);
 410
 411         if (ra->state != RADV_STATE_IDLE)
 412                 return 0;
 413
 414         r = radv_setup_recv_event(ra);
 415         if (r < 0)
 416                 goto fail;
 417
 418         r = event_reset_time(ra->event, &ra->timeout_event_source,
 419                              CLOCK_BOOTTIME,
 420                              0, 0,
 421                              radv_timeout, ra,
 422                              ra->event_priority, "radv-timeout", true);
 423         if (r < 0)
 424                 goto fail;
 425
 426         ra->state = RADV_STATE_ADVERTISING;
 427
 428         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 429
 430         return 0;
 431
 432  fail:
 433         radv_reset(ra);
 434
 435         return r;
 436 }
 437
 438 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 439         assert_return(ra, -EINVAL);
 440         assert_return(ifindex > 0, -EINVAL);
 441
 442         if (ra->state != RADV_STATE_IDLE)
 443                 return -EBUSY;
 444
 445         ra->ifindex = ifindex;
 446
 447         return 0;
 448 }
 449
 450 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 451         assert_return(ra, -EINVAL);
 452         assert_return(ifname, -EINVAL);
 453
 454         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 455                 return -EINVAL;
 456
 457         return free_and_strdup(&ra->ifname, ifname);
 458 }
 459
 460 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 461         int r;
 462
 463         assert_return(ra, -EINVAL);
 464
 465         r = get_ifname(ra->ifindex, &ra->ifname);
 466         if (r < 0)
 467                 return r;
 468
 469         if (ret)
 470                 *ret = ra->ifname;
 471
 472         return 0;
 473 }
 474
 475 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 476         assert_return(ra, -EINVAL);
 477
 478         if (ra->state != RADV_STATE_IDLE)
 479                 return -EBUSY;
 480
 481         if (mac_addr)
 482                 ra->mac_addr = *mac_addr;
 483         else
 484                 zero(ra->mac_addr);
 485
 486         return 0;
 487 }
 488
 489 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 490         assert_return(ra, -EINVAL);
 491         assert_return(mtu >= 1280, -EINVAL);
 492
 493         ra->mtu = mtu;
 494
 495         return 0;
 496 }
 497
 498 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 499         assert_return(ra, -EINVAL);
 500
 501         if (ra->state != RADV_STATE_IDLE)
 502                 return -EBUSY;
 503
 504         ra->hop_limit = hop_limit;
 505
 506         return 0;
 507 }
 508
 509 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 510         assert_return(ra, -EINVAL);
 511
 512         if (ra->state != RADV_STATE_IDLE)
 513                 return -EBUSY;
 514
 515         if (usec > RADV_MAX_RETRANSMIT_USEC)
 516                 return -EINVAL;
 517
 518         ra->retransmit_usec = usec;
 519         return 0;
 520 }
 521
 522 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 523         assert_return(ra, -EINVAL);
 524
 525         if (ra->state != RADV_STATE_IDLE)
 526                 return -EBUSY;
 527
 528         if (!router_lifetime_is_valid(usec))
 529                 return -EINVAL;
 530
 531         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 532          * to (00) by the sender..." */
 533         if (usec == 0 &&
 534             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 535                 return -EINVAL;
 536
 537         ra->lifetime_usec = usec;
 538         return 0;
 539 }
 540
 541 int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 542         assert_return(ra, -EINVAL);
 543
 544         if (ra->state != RADV_STATE_IDLE)
 545                 return -EBUSY;
 546
 547         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 548
 549         return 0;
 550 }
 551
 552 int sd_radv_set_other_information(sd_radv *ra, int other) {
 553         assert_return(ra, -EINVAL);
 554
 555         if (ra->state != RADV_STATE_IDLE)
 556                 return -EBUSY;
 557
 558         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 559
 560         return 0;
 561 }
 562
 563 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 564         assert_return(ra, -EINVAL);
 565         assert_return(IN_SET(preference,
 566                              SD_NDISC_PREFERENCE_LOW,
 567                              SD_NDISC_PREFERENCE_MEDIUM,
 568                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 569
 570         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 571          * to (00) by the sender..." */
 572         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 573                 return -EINVAL;
 574
 575         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 576
 577         return 0;
 578 }
 579
 580 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 581         assert_return(ra, -EINVAL);
 582
 583         if (ra->state != RADV_STATE_IDLE)
 584                 return -EBUSY;
 585
 586         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 587
 588         return 0;
 589 }
 590
 591 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 592         assert_return(ra, -EINVAL);
 593
 594         if (ra->state != RADV_STATE_IDLE)
 595                 return -EBUSY;
 596
 597         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 598
 599         return 0;
 600 }
 601
 602 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 603         assert_return(ra, -EINVAL);
 604
 605         if (ra->state != RADV_STATE_IDLE)
 606                 return -EBUSY;
 607
 608         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 609                 return -EINVAL;
 610
 611         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 612         return 0;
 613 }
 614
 615 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 616         sd_radv_prefix *found = NULL;
 617         int r;
 618
 619         assert_return(ra, -EINVAL);
 620         assert_return(p, -EINVAL);
 621
 622         /* Refuse prefixes that don't have a prefix set */
 623         if (in6_addr_is_null(&p->opt.in6_addr))
 624                 return -ENOEXEC;
 625
 626         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 627
 628         LIST_FOREACH(prefix, cur, ra->prefixes) {
 629                 r = in_addr_prefix_intersect(AF_INET6,
 630                                              (const union in_addr_union*) &cur->opt.in6_addr,
 631                                              cur->opt.prefixlen,
 632                                              (const union in_addr_union*) &p->opt.in6_addr,
 633                                              p->opt.prefixlen);
 634                 if (r < 0)
 635                         return r;
 636                 if (r == 0)
 637                         continue;
 638
 639                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 640                         found = cur;
 641                         break;
 642                 }
 643
 644                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 645                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 646                                       addr_p,
 647                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 648         }
 649
 650         if (found) {
 651                 /* p and cur may be equivalent. First increment the reference counter. */
 652                 sd_radv_prefix_ref(p);
 653
 654                 /* Then, remove the old entry. */
 655                 LIST_REMOVE(prefix, ra->prefixes, found);
 656                 sd_radv_prefix_unref(found);
 657
 658                 /* Finally, add the new entry. */
 659                 LIST_APPEND(prefix, ra->prefixes, p);
 660
 661                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 662                          addr_p,
 663                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 664                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 665         } else {
 666                 /* The prefix is new. Let's simply add it. */
 667
 668                 sd_radv_prefix_ref(p);
 669                 LIST_APPEND(prefix, ra->prefixes, p);
 670                 ra->n_prefixes++;
 671
 672                 log_radv(ra, "Added prefix %s", addr_p);
 673         }
 674
 675         if (ra->state == RADV_STATE_IDLE)
 676                 return 0;
 677
 678         if (ra->ra_sent == 0)
 679                 return 0;
 680
 681         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 682         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 683         if (r < 0)
 684                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 685         else
 686                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 687
 688         return 0;
 689 }
 690
 691 void sd_radv_remove_prefix(
 692                 sd_radv *ra,
 693                 const struct in6_addr *prefix,
 694                 unsigned char prefixlen) {
 695
 696         if (!ra)
 697                 return;
 698
 699         if (!prefix)
 700                 return;
 701
 702         LIST_FOREACH(prefix, cur, ra->prefixes) {
 703                 if (prefixlen != cur->opt.prefixlen)
 704                         continue;
 705
 706                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 707                         continue;
 708
 709                 LIST_REMOVE(prefix, ra->prefixes, cur);
 710                 ra->n_prefixes--;
 711                 sd_radv_prefix_unref(cur);
 712                 return;
 713         }
 714 }
 715
 716 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 717         sd_radv_route_prefix *found = NULL;
 718         int r;
 719
 720         assert_return(ra, -EINVAL);
 721         assert_return(p, -EINVAL);
 722
 723         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 724
 725         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 726                 r = in_addr_prefix_intersect(AF_INET6,
 727                                              (const union in_addr_union*) &cur->opt.in6_addr,
 728                                              cur->opt.prefixlen,
 729                                              (const union in_addr_union*) &p->opt.in6_addr,
 730                                              p->opt.prefixlen);
 731                 if (r < 0)
 732                         return r;
 733                 if (r == 0)
 734                         continue;
 735
 736                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 737                         found = cur;
 738                         break;
 739                 }
 740
 741                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 742                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 743                                       addr_p,
 744                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 745         }
 746
 747         if (found) {
 748                 /* p and cur may be equivalent. First increment the reference counter. */
 749                 sd_radv_route_prefix_ref(p);
 750
 751                 /* Then, remove the old entry. */
 752                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 753                 sd_radv_route_prefix_unref(found);
 754
 755                 /* Finally, add the new entry. */
 756                 LIST_APPEND(prefix, ra->route_prefixes, p);
 757
 758                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 759                          strna(addr_p),
 760                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 761         } else {
 762                 /* The route prefix is new. Let's simply add it. */
 763
 764                 sd_radv_route_prefix_ref(p);
 765                 LIST_APPEND(prefix, ra->route_prefixes, p);
 766                 ra->n_route_prefixes++;
 767
 768                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 769         }
 770
 771         if (ra->state == RADV_STATE_IDLE)
 772                 return 0;
 773
 774         if (ra->ra_sent == 0)
 775                 return 0;
 776
 777         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 778         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 779         if (r < 0)
 780                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 781                                strna(addr_p));
 782         else
 783                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 784
 785         return 0;
 786 }
 787
 788 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 789         sd_radv_pref64_prefix *found = NULL;
 790         int r;
 791
 792         assert_return(ra, -EINVAL);
 793         assert_return(p, -EINVAL);
 794
 795         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 796
 797         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 798                 r = in_addr_prefix_intersect(AF_INET6,
 799                                              (const union in_addr_union*) &cur->in6_addr,
 800                                              cur->prefixlen,
 801                                              (const union in_addr_union*) &p->in6_addr,
 802                                              p->prefixlen);
 803                 if (r < 0)
 804                         return r;
 805                 if (r == 0)
 806                         continue;
 807
 808                 if (cur->prefixlen == p->prefixlen) {
 809                         found = cur;
 810                         break;
 811                 }
 812
 813                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 814                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 815                                       addr_p,
 816                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 817         }
 818
 819         if (found) {
 820                 /* p and cur may be equivalent. First increment the reference counter. */
 821                 sd_radv_pref64_prefix_ref(p);
 822
 823                 /* Then, remove the old entry. */
 824                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 825                 sd_radv_pref64_prefix_unref(found);
 826
 827                 /* Finally, add the new entry. */
 828                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 829
 830                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 831                          strna(addr_p),
 832                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 833         } else {
 834                 /* The route prefix is new. Let's simply add it. */
 835
 836                 sd_radv_pref64_prefix_ref(p);
 837                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 838                 ra->n_pref64_prefixes++;
 839
 840                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 841         }
 842
 843         if (ra->state == RADV_STATE_IDLE)
 844                 return 0;
 845
 846         if (ra->ra_sent == 0)
 847                 return 0;
 848
 849         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 850         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 851         if (r < 0)
 852                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 853                                strna(addr_p));
 854         else
 855                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 856
 857         return 0;
 858 }
 859
 860 int sd_radv_set_rdnss(
 861                 sd_radv *ra,
 862                 uint64_t lifetime_usec,
 863                 const struct in6_addr *dns,
 864                 size_t n_dns) {
 865
 866         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 867         size_t len;
 868
 869         assert_return(ra, -EINVAL);
 870         assert_return(n_dns < 128, -EINVAL);
 871
 872         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 873                 return -EINVAL;
 874
 875         if (!dns || n_dns == 0) {
 876                 ra->rdnss = mfree(ra->rdnss);
 877                 ra->n_rdnss = 0;
 878
 879                 return 0;
 880         }
 881
 882         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 883
 884         opt_rdnss = malloc0(len);
 885         if (!opt_rdnss)
 886                 return -ENOMEM;
 887
 888         opt_rdnss->type = RADV_OPT_RDNSS;
 889         opt_rdnss->length = len / 8;
 890         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 891
 892         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 893
 894         free_and_replace(ra->rdnss, opt_rdnss);
 895
 896         ra->n_rdnss = n_dns;
 897
 898         return 0;
 899 }
 900
 901 int sd_radv_set_dnssl(
 902                 sd_radv *ra,
 903                 uint64_t lifetime_usec,
 904                 char **search_list) {
 905
 906         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 907         size_t len = 0;
 908         uint8_t *p;
 909
 910         assert_return(ra, -EINVAL);
 911
 912         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 913                 return -EINVAL;
 914
 915         if (strv_isempty(search_list)) {
 916                 ra->dnssl = mfree(ra->dnssl);
 917                 return 0;
 918         }
 919
 920         STRV_FOREACH(s, search_list)
 921                 len += strlen(*s) + 2;
 922
 923         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 924
 925         opt_dnssl = malloc0(len);
 926         if (!opt_dnssl)
 927                 return -ENOMEM;
 928
 929         opt_dnssl->type = RADV_OPT_DNSSL;
 930         opt_dnssl->length = len / 8;
 931         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 932
 933         p = (uint8_t *)(opt_dnssl + 1);
 934         len -= sizeof(struct sd_radv_opt_dns);
 935
 936         STRV_FOREACH(s, search_list) {
 937                 int r;
 938
 939                 r = dns_name_to_wire_format(*s, p, len, false);
 940                 if (r < 0)
 941                         return r;
 942
 943                 if (len < (size_t)r)
 944                         return -ENOBUFS;
 945
 946                 p += r;
 947                 len -= r;
 948         }
 949
 950         free_and_replace(ra->dnssl, opt_dnssl);
 951
 952         return 0;
 953 }
 954
 955 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 956         sd_radv_prefix *p;
 957
 958         assert_return(ret, -EINVAL);
 959
 960         p = new(sd_radv_prefix, 1);
 961         if (!p)
 962                 return -ENOMEM;
 963
 964         *p = (sd_radv_prefix) {
 965                 .n_ref = 1,
 966
 967                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 968                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 969                 .opt.prefixlen = 64,
 970
 971                 /* RFC 4861, Section 6.2.1 */
 972                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 973
 974                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 975                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 976                 .valid_until = USEC_INFINITY,
 977                 .preferred_until = USEC_INFINITY,
 978         };
 979
 980         *ret = p;
 981         return 0;
 982 }
 983
 984 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
 985
 986 int sd_radv_prefix_set_prefix(
 987                 sd_radv_prefix *p,
 988                 const struct in6_addr *in6_addr,
 989                 unsigned char prefixlen) {
 990
 991         assert_return(p, -EINVAL);
 992         assert_return(in6_addr, -EINVAL);
 993
 994         if (prefixlen < 3 || prefixlen > 128)
 995                 return -EINVAL;
 996
 997         if (prefixlen > 64)
 998                 /* unusual but allowed, log it */
 999                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
1000
1001         p->opt.in6_addr = *in6_addr;
1002         p->opt.prefixlen = prefixlen;
1003
1004         return 0;
1005 }
1006
1007 int sd_radv_prefix_get_prefix(
1008                 sd_radv_prefix *p,
1009                 struct in6_addr *ret_in6_addr,
1010                 unsigned char *ret_prefixlen) {
1011
1012         assert_return(p, -EINVAL);
1013         assert_return(ret_in6_addr, -EINVAL);
1014         assert_return(ret_prefixlen, -EINVAL);
1015
1016         *ret_in6_addr = p->opt.in6_addr;
1017         *ret_prefixlen = p->opt.prefixlen;
1018
1019         return 0;
1020 }
1021
1022 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1023         assert_return(p, -EINVAL);
1024
1025         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1026
1027         return 0;
1028 }
1029
1030 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1031         assert_return(p, -EINVAL);
1032
1033         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1034
1035         return 0;
1036 }
1037
1038 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1039         assert_return(p, -EINVAL);
1040
1041         p->lifetime_valid_usec = lifetime_usec;
1042         p->valid_until = valid_until;
1043
1044         return 0;
1045 }
1046
1047 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1048         assert_return(p, -EINVAL);
1049
1050         p->lifetime_preferred_usec = lifetime_usec;
1051         p->preferred_until = valid_until;
1052
1053         return 0;
1054 }
1055
1056 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1057         sd_radv_route_prefix *p;
1058
1059         assert_return(ret, -EINVAL);
1060
1061         p = new(sd_radv_route_prefix, 1);
1062         if (!p)
1063                 return -ENOMEM;
1064
1065         *p = (sd_radv_route_prefix) {
1066                 .n_ref = 1,
1067
1068                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1069                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1070                 .opt.prefixlen = 64,
1071
1072                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1073                 .valid_until = USEC_INFINITY,
1074         };
1075
1076         *ret = p;
1077         return 0;
1078 }
1079
1080 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1081
1082 int sd_radv_route_prefix_set_prefix(
1083                 sd_radv_route_prefix *p,
1084                 const struct in6_addr *in6_addr,
1085                 unsigned char prefixlen) {
1086
1087         assert_return(p, -EINVAL);
1088         assert_return(in6_addr, -EINVAL);
1089
1090         if (prefixlen > 128)
1091                 return -EINVAL;
1092
1093         if (prefixlen > 64)
1094                 /* unusual but allowed, log it */
1095                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1096
1097         p->opt.in6_addr = *in6_addr;
1098         p->opt.prefixlen = prefixlen;
1099
1100         return 0;
1101 }
1102
1103 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1104         assert_return(p, -EINVAL);
1105
1106         p->lifetime_usec = lifetime_usec;
1107         p->valid_until = valid_until;
1108
1109         return 0;
1110 }
1111
1112 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1113         sd_radv_pref64_prefix *p;
1114
1115         assert_return(ret, -EINVAL);
1116
1117         p = new(sd_radv_pref64_prefix, 1);
1118         if (!p)
1119                 return -ENOMEM;
1120
1121         *p = (sd_radv_pref64_prefix) {
1122                 .n_ref = 1,
1123
1124                 .opt.type = RADV_OPT_PREF64,
1125                 .opt.length = 2,
1126         };
1127
1128         *ret = p;
1129         return 0;
1130 }
1131
1132 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1133
1134 int sd_radv_pref64_prefix_set_prefix(
1135                 sd_radv_pref64_prefix *p,
1136                 const struct in6_addr *prefix,
1137                 uint8_t prefixlen,
1138                 uint64_t lifetime_usec) {
1139
1140         uint16_t pref64_lifetime;
1141         uint8_t prefixlen_code;
1142         int r;
1143
1144         assert_return(p, -EINVAL);
1145         assert_return(prefix, -EINVAL);
1146
1147         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1148         if (r < 0)
1149                 return log_radv_errno(NULL, r,
1150                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1151
1152         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1153                 return -EINVAL;
1154
1155         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1156         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1157         pref64_lifetime |= prefixlen_code;
1158
1159         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1160         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1161
1162         p->in6_addr = *prefix;
1163         p->prefixlen = prefixlen;
1164
1165         return 0;
1166 }