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 "network-common.h"
  23 #include "radv-internal.h"
  24 #include "random-util.h"
  25 #include "socket-util.h"
  26 #include "string-util.h"
  27 #include "strv.h"
  28 #include "unaligned.h"
  29
  30 int sd_radv_new(sd_radv **ret) {
  31         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  32
  33         assert_return(ret, -EINVAL);
  34
  35         ra = new(sd_radv, 1);
  36         if (!ra)
  37                 return -ENOMEM;
  38
  39         *ra = (sd_radv) {
  40                 .n_ref = 1,
  41                 .fd = -EBADF,
  42                 .lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
  43         };
  44
  45         *ret = TAKE_PTR(ra);
  46
  47         return 0;
  48 }
  49
  50 int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  51         int r;
  52
  53         assert_return(ra, -EINVAL);
  54         assert_return(!ra->event, -EBUSY);
  55
  56         if (event)
  57                 ra->event = sd_event_ref(event);
  58         else {
  59                 r = sd_event_default(&ra->event);
  60                 if (r < 0)
  61                         return 0;
  62         }
  63
  64         ra->event_priority = priority;
  65
  66         return 0;
  67 }
  68
  69 int sd_radv_detach_event(sd_radv *ra) {
  70
  71         assert_return(ra, -EINVAL);
  72
  73         ra->event = sd_event_unref(ra->event);
  74         return 0;
  75 }
  76
  77 sd_event *sd_radv_get_event(sd_radv *ra) {
  78         assert_return(ra, NULL);
  79
  80         return ra->event;
  81 }
  82
  83 int sd_radv_is_running(sd_radv *ra) {
  84         assert_return(ra, false);
  85
  86         return ra->state != RADV_STATE_IDLE;
  87 }
  88
  89 static void radv_reset(sd_radv *ra) {
  90         assert(ra);
  91
  92         (void) event_source_disable(ra->timeout_event_source);
  93
  94         ra->recv_event_source = sd_event_source_disable_unref(ra->recv_event_source);
  95
  96         ra->ra_sent = 0;
  97 }
  98
  99 static sd_radv *radv_free(sd_radv *ra) {
 100         if (!ra)
 101                 return NULL;
 102
 103         LIST_CLEAR(prefix, ra->prefixes, sd_radv_prefix_unref);
 104         LIST_CLEAR(prefix, ra->route_prefixes, sd_radv_route_prefix_unref);
 105         LIST_CLEAR(prefix, ra->pref64_prefixes, sd_radv_pref64_prefix_unref);
 106
 107         free(ra->rdnss);
 108         free(ra->dnssl);
 109
 110         radv_reset(ra);
 111
 112         sd_event_source_unref(ra->timeout_event_source);
 113         sd_radv_detach_event(ra);
 114
 115         ra->fd = safe_close(ra->fd);
 116         free(ra->ifname);
 117
 118         return mfree(ra);
 119 }
 120
 121 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
 122
 123 static bool router_lifetime_is_valid(usec_t lifetime_usec) {
 124         return lifetime_usec == 0 ||
 125                 (lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
 126                  lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
 127 }
 128
 129 static int radv_send(sd_radv *ra, const struct in6_addr *dst, usec_t lifetime_usec) {
 130         struct sockaddr_in6 dst_addr = {
 131                 .sin6_family = AF_INET6,
 132                 .sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT,
 133         };
 134         struct nd_router_advert adv = {};
 135         struct {
 136                 struct nd_opt_hdr opthdr;
 137                 struct ether_addr slladdr;
 138         } _packed_ opt_mac = {
 139                 .opthdr = {
 140                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 141                         .nd_opt_len = (sizeof(struct nd_opt_hdr) +
 142                                        sizeof(struct ether_addr) - 1) /8 + 1,
 143                 },
 144         };
 145         struct nd_opt_mtu opt_mtu =  {
 146                 .nd_opt_mtu_type = ND_OPT_MTU,
 147                 .nd_opt_mtu_len = 1,
 148         };
 149         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, N pref64 prefixes, RDNSS,
 150          * DNSSL, and home agent. */
 151         struct iovec iov[6 + ra->n_prefixes + ra->n_route_prefixes + ra->n_pref64_prefixes];
 152         struct msghdr msg = {
 153                 .msg_name = &dst_addr,
 154                 .msg_namelen = sizeof(dst_addr),
 155                 .msg_iov = iov,
 156         };
 157         usec_t time_now;
 158         int r;
 159
 160         assert(ra);
 161         assert(router_lifetime_is_valid(lifetime_usec));
 162
 163         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 164         if (r < 0)
 165                 return r;
 166
 167         if (dst && in6_addr_is_set(dst))
 168                 dst_addr.sin6_addr = *dst;
 169
 170         adv.nd_ra_type = ND_ROUTER_ADVERT;
 171         adv.nd_ra_curhoplimit = ra->hop_limit;
 172         adv.nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec);
 173         adv.nd_ra_flags_reserved = ra->flags;
 174         assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
 175         adv.nd_ra_router_lifetime = usec_to_be16_sec(lifetime_usec);
 176         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 177
 178         /* MAC address is optional, either because the link does not use L2
 179            addresses or load sharing is desired. See RFC 4861, Section 4.2 */
 180         if (!ether_addr_is_null(&ra->mac_addr)) {
 181                 opt_mac.slladdr = ra->mac_addr;
 182                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 183         }
 184
 185         if (ra->mtu > 0) {
 186                 opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu);
 187                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 188         }
 189
 190         LIST_FOREACH(prefix, p, ra->prefixes) {
 191                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 192
 193                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 194                                           p->lifetime_valid_usec);
 195
 196                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 197                                                p->lifetime_preferred_usec,
 198                                                lifetime_valid_usec);
 199
 200                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 201                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 202
 203                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 204         }
 205
 206         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 207                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 208                                                         rt->lifetime_usec));
 209
 210                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 211         }
 212
 213         LIST_FOREACH(prefix, p, ra->pref64_prefixes)
 214                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 215
 216         if (ra->rdnss)
 217                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 218
 219         if (ra->dnssl)
 220                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 221
 222         if (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
 223                 ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
 224                 ra->home_agent.nd_opt_home_agent_info_len = 1;
 225
 226                 /* 0 means to place the current Router Lifetime value */
 227                 if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
 228                         ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
 229
 230                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
 231         }
 232
 233         if (sendmsg(ra->fd, &msg, 0) < 0)
 234                 return -errno;
 235
 236         return 0;
 237 }
 238
 239 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 240         sd_radv *ra = ASSERT_PTR(userdata);
 241         struct in6_addr src;
 242         triple_timestamp timestamp;
 243         int r;
 244
 245         assert(s);
 246         assert(ra->event);
 247
 248         ssize_t buflen = next_datagram_size_fd(fd);
 249         if (ERRNO_IS_NEG_TRANSIENT(buflen) || ERRNO_IS_NEG_DISCONNECT(buflen))
 250                 return 0;
 251         if (buflen < 0) {
 252                 log_radv_errno(ra, buflen, "Failed to determine datagram size to read, ignoring: %m");
 253                 return 0;
 254         }
 255
 256         _cleanup_free_ char *buf = new0(char, buflen);
 257         if (!buf)
 258                 return -ENOMEM;
 259
 260         r = icmp6_receive(fd, buf, buflen, &src, &timestamp);
 261         if (ERRNO_IS_NEG_TRANSIENT(r) || ERRNO_IS_NEG_DISCONNECT(r))
 262                 return 0;
 263         if (r < 0)
 264                 switch (r) {
 265                 case -EADDRNOTAVAIL:
 266                         log_radv(ra, "Received RS from neither link-local nor null address. Ignoring");
 267                         return 0;
 268
 269                 case -EMULTIHOP:
 270                         log_radv(ra, "Received RS with invalid hop limit. Ignoring.");
 271                         return 0;
 272
 273                 case -EPFNOSUPPORT:
 274                         log_radv(ra, "Received invalid source address from ICMPv6 socket. Ignoring.");
 275                         return 0;
 276
 277                 default:
 278                         log_radv_errno(ra, r, "Unexpected error receiving from ICMPv6 socket, ignoring: %m");
 279                         return 0;
 280                 }
 281
 282         if ((size_t) buflen < sizeof(struct nd_router_solicit)) {
 283                 log_radv(ra, "Too short packet received, ignoring");
 284                 return 0;
 285         }
 286
 287         /* TODO: if the sender address is null, check that the message does not have the source link-layer
 288          * address option. See RFC 4861 Section 6.1.1. */
 289
 290         const char *addr = IN6_ADDR_TO_STRING(&src);
 291
 292         r = radv_send(ra, &src, ra->lifetime_usec);
 293         if (r < 0)
 294                 log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", addr);
 295         else
 296                 log_radv(ra, "Sent solicited Router Advertisement to %s", addr);
 297
 298         return 0;
 299 }
 300
 301 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 302         usec_t min_timeout, max_timeout, time_now, timeout;
 303         sd_radv *ra = ASSERT_PTR(userdata);
 304         int r;
 305
 306         assert(s);
 307         assert(ra->event);
 308         assert(router_lifetime_is_valid(ra->lifetime_usec));
 309
 310         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 311         if (r < 0)
 312                 goto fail;
 313
 314         r = radv_send(ra, NULL, ra->lifetime_usec);
 315         if (r < 0)
 316                 log_radv_errno(ra, r, "Unable to send Router Advertisement, ignoring: %m");
 317
 318         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 319         if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 320                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 321         else
 322                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 323
 324         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 325          * so lower the interval here */
 326         if (ra->lifetime_usec > 0)
 327                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 328
 329         if (max_timeout >= 9 * USEC_PER_SEC)
 330                 min_timeout = max_timeout / 3;
 331         else
 332                 min_timeout = max_timeout * 3 / 4;
 333
 334         /* RFC 4861, Section 6.2.1.
 335          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 336          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 337         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 338         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 339         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 340         assert(min_timeout <= max_timeout * 3 / 4);
 341
 342         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 343         log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 344
 345         r = event_reset_time(ra->event, &ra->timeout_event_source,
 346                              CLOCK_BOOTTIME,
 347                              usec_add(time_now, timeout), MSEC_PER_SEC,
 348                              radv_timeout, ra,
 349                              ra->event_priority, "radv-timeout", true);
 350         if (r < 0)
 351                 goto fail;
 352
 353         ra->ra_sent++;
 354
 355         return 0;
 356
 357 fail:
 358         sd_radv_stop(ra);
 359
 360         return 0;
 361 }
 362
 363 int sd_radv_stop(sd_radv *ra) {
 364         int r;
 365
 366         if (!ra)
 367                 return 0;
 368
 369         if (ra->state == RADV_STATE_IDLE)
 370                 return 0;
 371
 372         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 373
 374         /* RFC 4861, Section 6.2.5, send at least one Router Advertisement
 375            with zero lifetime  */
 376         r = radv_send(ra, NULL, 0);
 377         if (r < 0)
 378                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
 379
 380         radv_reset(ra);
 381         ra->fd = safe_close(ra->fd);
 382         ra->state = RADV_STATE_IDLE;
 383
 384         return 0;
 385 }
 386
 387 int sd_radv_start(sd_radv *ra) {
 388         int r;
 389
 390         assert_return(ra, -EINVAL);
 391         assert_return(ra->event, -EINVAL);
 392         assert_return(ra->ifindex > 0, -EINVAL);
 393
 394         if (ra->state != RADV_STATE_IDLE)
 395                 return 0;
 396
 397         r = event_reset_time(ra->event, &ra->timeout_event_source,
 398                              CLOCK_BOOTTIME,
 399                              0, 0,
 400                              radv_timeout, ra,
 401                              ra->event_priority, "radv-timeout", true);
 402         if (r < 0)
 403                 goto fail;
 404
 405         r = icmp6_bind_router_advertisement(ra->ifindex);
 406         if (r < 0)
 407                 goto fail;
 408
 409         ra->fd = r;
 410
 411         r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra);
 412         if (r < 0)
 413                 goto fail;
 414
 415         r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority);
 416         if (r < 0)
 417                 goto fail;
 418
 419         (void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message");
 420
 421         ra->state = RADV_STATE_ADVERTISING;
 422
 423         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 424
 425         return 0;
 426
 427  fail:
 428         radv_reset(ra);
 429
 430         return r;
 431 }
 432
 433 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 434         assert_return(ra, -EINVAL);
 435         assert_return(ifindex > 0, -EINVAL);
 436
 437         if (ra->state != RADV_STATE_IDLE)
 438                 return -EBUSY;
 439
 440         ra->ifindex = ifindex;
 441
 442         return 0;
 443 }
 444
 445 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 446         assert_return(ra, -EINVAL);
 447         assert_return(ifname, -EINVAL);
 448
 449         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 450                 return -EINVAL;
 451
 452         return free_and_strdup(&ra->ifname, ifname);
 453 }
 454
 455 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 456         int r;
 457
 458         assert_return(ra, -EINVAL);
 459
 460         r = get_ifname(ra->ifindex, &ra->ifname);
 461         if (r < 0)
 462                 return r;
 463
 464         if (ret)
 465                 *ret = ra->ifname;
 466
 467         return 0;
 468 }
 469
 470 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 471         assert_return(ra, -EINVAL);
 472
 473         if (ra->state != RADV_STATE_IDLE)
 474                 return -EBUSY;
 475
 476         if (mac_addr)
 477                 ra->mac_addr = *mac_addr;
 478         else
 479                 zero(ra->mac_addr);
 480
 481         return 0;
 482 }
 483
 484 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 485         assert_return(ra, -EINVAL);
 486         assert_return(mtu >= 1280, -EINVAL);
 487
 488         ra->mtu = mtu;
 489
 490         return 0;
 491 }
 492
 493 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 494         assert_return(ra, -EINVAL);
 495
 496         if (ra->state != RADV_STATE_IDLE)
 497                 return -EBUSY;
 498
 499         ra->hop_limit = hop_limit;
 500
 501         return 0;
 502 }
 503
 504 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 505         assert_return(ra, -EINVAL);
 506
 507         if (ra->state != RADV_STATE_IDLE)
 508                 return -EBUSY;
 509
 510         if (usec > RADV_MAX_RETRANSMIT_USEC)
 511                 return -EINVAL;
 512
 513         ra->retransmit_usec = usec;
 514         return 0;
 515 }
 516
 517 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 518         assert_return(ra, -EINVAL);
 519
 520         if (ra->state != RADV_STATE_IDLE)
 521                 return -EBUSY;
 522
 523         if (!router_lifetime_is_valid(usec))
 524                 return -EINVAL;
 525
 526         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 527          * to (00) by the sender..." */
 528         if (usec == 0 &&
 529             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 530                 return -EINVAL;
 531
 532         ra->lifetime_usec = usec;
 533         return 0;
 534 }
 535
 536 int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 537         assert_return(ra, -EINVAL);
 538
 539         if (ra->state != RADV_STATE_IDLE)
 540                 return -EBUSY;
 541
 542         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 543
 544         return 0;
 545 }
 546
 547 int sd_radv_set_other_information(sd_radv *ra, int other) {
 548         assert_return(ra, -EINVAL);
 549
 550         if (ra->state != RADV_STATE_IDLE)
 551                 return -EBUSY;
 552
 553         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 554
 555         return 0;
 556 }
 557
 558 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 559         assert_return(ra, -EINVAL);
 560         assert_return(IN_SET(preference,
 561                              SD_NDISC_PREFERENCE_LOW,
 562                              SD_NDISC_PREFERENCE_MEDIUM,
 563                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 564
 565         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 566          * to (00) by the sender..." */
 567         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 568                 return -EINVAL;
 569
 570         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 571
 572         return 0;
 573 }
 574
 575 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 576         assert_return(ra, -EINVAL);
 577
 578         if (ra->state != RADV_STATE_IDLE)
 579                 return -EBUSY;
 580
 581         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 582
 583         return 0;
 584 }
 585
 586 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 587         assert_return(ra, -EINVAL);
 588
 589         if (ra->state != RADV_STATE_IDLE)
 590                 return -EBUSY;
 591
 592         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 593
 594         return 0;
 595 }
 596
 597 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 598         assert_return(ra, -EINVAL);
 599
 600         if (ra->state != RADV_STATE_IDLE)
 601                 return -EBUSY;
 602
 603         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 604                 return -EINVAL;
 605
 606         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 607         return 0;
 608 }
 609
 610 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 611         sd_radv_prefix *found = NULL;
 612         int r;
 613
 614         assert_return(ra, -EINVAL);
 615         assert_return(p, -EINVAL);
 616
 617         /* Refuse prefixes that don't have a prefix set */
 618         if (in6_addr_is_null(&p->opt.in6_addr))
 619                 return -ENOEXEC;
 620
 621         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 622
 623         LIST_FOREACH(prefix, cur, ra->prefixes) {
 624                 r = in_addr_prefix_intersect(AF_INET6,
 625                                              (const union in_addr_union*) &cur->opt.in6_addr,
 626                                              cur->opt.prefixlen,
 627                                              (const union in_addr_union*) &p->opt.in6_addr,
 628                                              p->opt.prefixlen);
 629                 if (r < 0)
 630                         return r;
 631                 if (r == 0)
 632                         continue;
 633
 634                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 635                         found = cur;
 636                         break;
 637                 }
 638
 639                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 640                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 641                                       addr_p,
 642                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 643         }
 644
 645         if (found) {
 646                 /* p and cur may be equivalent. First increment the reference counter. */
 647                 sd_radv_prefix_ref(p);
 648
 649                 /* Then, remove the old entry. */
 650                 LIST_REMOVE(prefix, ra->prefixes, found);
 651                 sd_radv_prefix_unref(found);
 652
 653                 /* Finally, add the new entry. */
 654                 LIST_APPEND(prefix, ra->prefixes, p);
 655
 656                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 657                          addr_p,
 658                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 659                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 660         } else {
 661                 /* The prefix is new. Let's simply add it. */
 662
 663                 sd_radv_prefix_ref(p);
 664                 LIST_APPEND(prefix, ra->prefixes, p);
 665                 ra->n_prefixes++;
 666
 667                 log_radv(ra, "Added prefix %s", addr_p);
 668         }
 669
 670         if (ra->state == RADV_STATE_IDLE)
 671                 return 0;
 672
 673         if (ra->ra_sent == 0)
 674                 return 0;
 675
 676         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 677         r = radv_send(ra, NULL, ra->lifetime_usec);
 678         if (r < 0)
 679                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 680         else
 681                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 682
 683         return 0;
 684 }
 685
 686 void sd_radv_remove_prefix(
 687                 sd_radv *ra,
 688                 const struct in6_addr *prefix,
 689                 unsigned char prefixlen) {
 690
 691         if (!ra)
 692                 return;
 693
 694         if (!prefix)
 695                 return;
 696
 697         LIST_FOREACH(prefix, cur, ra->prefixes) {
 698                 if (prefixlen != cur->opt.prefixlen)
 699                         continue;
 700
 701                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 702                         continue;
 703
 704                 LIST_REMOVE(prefix, ra->prefixes, cur);
 705                 ra->n_prefixes--;
 706                 sd_radv_prefix_unref(cur);
 707                 return;
 708         }
 709 }
 710
 711 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 712         sd_radv_route_prefix *found = NULL;
 713         int r;
 714
 715         assert_return(ra, -EINVAL);
 716         assert_return(p, -EINVAL);
 717
 718         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 719
 720         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 721                 r = in_addr_prefix_intersect(AF_INET6,
 722                                              (const union in_addr_union*) &cur->opt.in6_addr,
 723                                              cur->opt.prefixlen,
 724                                              (const union in_addr_union*) &p->opt.in6_addr,
 725                                              p->opt.prefixlen);
 726                 if (r < 0)
 727                         return r;
 728                 if (r == 0)
 729                         continue;
 730
 731                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 732                         found = cur;
 733                         break;
 734                 }
 735
 736                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 737                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 738                                       addr_p,
 739                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 740         }
 741
 742         if (found) {
 743                 /* p and cur may be equivalent. First increment the reference counter. */
 744                 sd_radv_route_prefix_ref(p);
 745
 746                 /* Then, remove the old entry. */
 747                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 748                 sd_radv_route_prefix_unref(found);
 749
 750                 /* Finally, add the new entry. */
 751                 LIST_APPEND(prefix, ra->route_prefixes, p);
 752
 753                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 754                          strna(addr_p),
 755                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 756         } else {
 757                 /* The route prefix is new. Let's simply add it. */
 758
 759                 sd_radv_route_prefix_ref(p);
 760                 LIST_APPEND(prefix, ra->route_prefixes, p);
 761                 ra->n_route_prefixes++;
 762
 763                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 764         }
 765
 766         if (ra->state == RADV_STATE_IDLE)
 767                 return 0;
 768
 769         if (ra->ra_sent == 0)
 770                 return 0;
 771
 772         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 773         r = radv_send(ra, NULL, ra->lifetime_usec);
 774         if (r < 0)
 775                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 776                                strna(addr_p));
 777         else
 778                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 779
 780         return 0;
 781 }
 782
 783 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 784         sd_radv_pref64_prefix *found = NULL;
 785         int r;
 786
 787         assert_return(ra, -EINVAL);
 788         assert_return(p, -EINVAL);
 789
 790         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 791
 792         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 793                 r = in_addr_prefix_intersect(AF_INET6,
 794                                              (const union in_addr_union*) &cur->in6_addr,
 795                                              cur->prefixlen,
 796                                              (const union in_addr_union*) &p->in6_addr,
 797                                              p->prefixlen);
 798                 if (r < 0)
 799                         return r;
 800                 if (r == 0)
 801                         continue;
 802
 803                 if (cur->prefixlen == p->prefixlen) {
 804                         found = cur;
 805                         break;
 806                 }
 807
 808                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 809                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 810                                       addr_p,
 811                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 812         }
 813
 814         if (found) {
 815                 /* p and cur may be equivalent. First increment the reference counter. */
 816                 sd_radv_pref64_prefix_ref(p);
 817
 818                 /* Then, remove the old entry. */
 819                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 820                 sd_radv_pref64_prefix_unref(found);
 821
 822                 /* Finally, add the new entry. */
 823                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 824
 825                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 826                          strna(addr_p),
 827                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 828         } else {
 829                 /* The route prefix is new. Let's simply add it. */
 830
 831                 sd_radv_pref64_prefix_ref(p);
 832                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 833                 ra->n_pref64_prefixes++;
 834
 835                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 836         }
 837
 838         if (ra->state == RADV_STATE_IDLE)
 839                 return 0;
 840
 841         if (ra->ra_sent == 0)
 842                 return 0;
 843
 844         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 845         r = radv_send(ra, NULL, ra->lifetime_usec);
 846         if (r < 0)
 847                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 848                                strna(addr_p));
 849         else
 850                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 851
 852         return 0;
 853 }
 854
 855 int sd_radv_set_rdnss(
 856                 sd_radv *ra,
 857                 uint64_t lifetime_usec,
 858                 const struct in6_addr *dns,
 859                 size_t n_dns) {
 860
 861         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 862         size_t len;
 863
 864         assert_return(ra, -EINVAL);
 865         assert_return(n_dns < 128, -EINVAL);
 866
 867         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 868                 return -EINVAL;
 869
 870         if (!dns || n_dns == 0) {
 871                 ra->rdnss = mfree(ra->rdnss);
 872                 ra->n_rdnss = 0;
 873
 874                 return 0;
 875         }
 876
 877         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 878
 879         opt_rdnss = malloc0(len);
 880         if (!opt_rdnss)
 881                 return -ENOMEM;
 882
 883         opt_rdnss->type = RADV_OPT_RDNSS;
 884         opt_rdnss->length = len / 8;
 885         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 886
 887         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 888
 889         free_and_replace(ra->rdnss, opt_rdnss);
 890
 891         ra->n_rdnss = n_dns;
 892
 893         return 0;
 894 }
 895
 896 int sd_radv_set_dnssl(
 897                 sd_radv *ra,
 898                 uint64_t lifetime_usec,
 899                 char **search_list) {
 900
 901         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 902         size_t len = 0;
 903         uint8_t *p;
 904
 905         assert_return(ra, -EINVAL);
 906
 907         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 908                 return -EINVAL;
 909
 910         if (strv_isempty(search_list)) {
 911                 ra->dnssl = mfree(ra->dnssl);
 912                 return 0;
 913         }
 914
 915         STRV_FOREACH(s, search_list)
 916                 len += strlen(*s) + 2;
 917
 918         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 919
 920         opt_dnssl = malloc0(len);
 921         if (!opt_dnssl)
 922                 return -ENOMEM;
 923
 924         opt_dnssl->type = RADV_OPT_DNSSL;
 925         opt_dnssl->length = len / 8;
 926         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 927
 928         p = (uint8_t *)(opt_dnssl + 1);
 929         len -= sizeof(struct sd_radv_opt_dns);
 930
 931         STRV_FOREACH(s, search_list) {
 932                 int r;
 933
 934                 r = dns_name_to_wire_format(*s, p, len, false);
 935                 if (r < 0)
 936                         return r;
 937
 938                 if (len < (size_t)r)
 939                         return -ENOBUFS;
 940
 941                 p += r;
 942                 len -= r;
 943         }
 944
 945         free_and_replace(ra->dnssl, opt_dnssl);
 946
 947         return 0;
 948 }
 949
 950 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 951         sd_radv_prefix *p;
 952
 953         assert_return(ret, -EINVAL);
 954
 955         p = new(sd_radv_prefix, 1);
 956         if (!p)
 957                 return -ENOMEM;
 958
 959         *p = (sd_radv_prefix) {
 960                 .n_ref = 1,
 961
 962                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 963                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 964                 .opt.prefixlen = 64,
 965
 966                 /* RFC 4861, Section 6.2.1 */
 967                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 968
 969                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 970                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 971                 .valid_until = USEC_INFINITY,
 972                 .preferred_until = USEC_INFINITY,
 973         };
 974
 975         *ret = p;
 976         return 0;
 977 }
 978
 979 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
 980
 981 int sd_radv_prefix_set_prefix(
 982                 sd_radv_prefix *p,
 983                 const struct in6_addr *in6_addr,
 984                 unsigned char prefixlen) {
 985
 986         assert_return(p, -EINVAL);
 987         assert_return(in6_addr, -EINVAL);
 988
 989         if (prefixlen < 3 || prefixlen > 128)
 990                 return -EINVAL;
 991
 992         if (prefixlen > 64)
 993                 /* unusual but allowed, log it */
 994                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
 995
 996         p->opt.in6_addr = *in6_addr;
 997         p->opt.prefixlen = prefixlen;
 998
 999         return 0;
1000 }
1001
1002 int sd_radv_prefix_get_prefix(
1003                 sd_radv_prefix *p,
1004                 struct in6_addr *ret_in6_addr,
1005                 unsigned char *ret_prefixlen) {
1006
1007         assert_return(p, -EINVAL);
1008         assert_return(ret_in6_addr, -EINVAL);
1009         assert_return(ret_prefixlen, -EINVAL);
1010
1011         *ret_in6_addr = p->opt.in6_addr;
1012         *ret_prefixlen = p->opt.prefixlen;
1013
1014         return 0;
1015 }
1016
1017 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1018         assert_return(p, -EINVAL);
1019
1020         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1021
1022         return 0;
1023 }
1024
1025 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1026         assert_return(p, -EINVAL);
1027
1028         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1029
1030         return 0;
1031 }
1032
1033 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1034         assert_return(p, -EINVAL);
1035
1036         p->lifetime_valid_usec = lifetime_usec;
1037         p->valid_until = valid_until;
1038
1039         return 0;
1040 }
1041
1042 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1043         assert_return(p, -EINVAL);
1044
1045         p->lifetime_preferred_usec = lifetime_usec;
1046         p->preferred_until = valid_until;
1047
1048         return 0;
1049 }
1050
1051 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1052         sd_radv_route_prefix *p;
1053
1054         assert_return(ret, -EINVAL);
1055
1056         p = new(sd_radv_route_prefix, 1);
1057         if (!p)
1058                 return -ENOMEM;
1059
1060         *p = (sd_radv_route_prefix) {
1061                 .n_ref = 1,
1062
1063                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1064                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1065                 .opt.prefixlen = 64,
1066
1067                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1068                 .valid_until = USEC_INFINITY,
1069         };
1070
1071         *ret = p;
1072         return 0;
1073 }
1074
1075 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1076
1077 int sd_radv_route_prefix_set_prefix(
1078                 sd_radv_route_prefix *p,
1079                 const struct in6_addr *in6_addr,
1080                 unsigned char prefixlen) {
1081
1082         assert_return(p, -EINVAL);
1083         assert_return(in6_addr, -EINVAL);
1084
1085         if (prefixlen > 128)
1086                 return -EINVAL;
1087
1088         if (prefixlen > 64)
1089                 /* unusual but allowed, log it */
1090                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1091
1092         p->opt.in6_addr = *in6_addr;
1093         p->opt.prefixlen = prefixlen;
1094
1095         return 0;
1096 }
1097
1098 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1099         assert_return(p, -EINVAL);
1100
1101         p->lifetime_usec = lifetime_usec;
1102         p->valid_until = valid_until;
1103
1104         return 0;
1105 }
1106
1107 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1108         sd_radv_pref64_prefix *p;
1109
1110         assert_return(ret, -EINVAL);
1111
1112         p = new(sd_radv_pref64_prefix, 1);
1113         if (!p)
1114                 return -ENOMEM;
1115
1116         *p = (sd_radv_pref64_prefix) {
1117                 .n_ref = 1,
1118
1119                 .opt.type = RADV_OPT_PREF64,
1120                 .opt.length = 2,
1121         };
1122
1123         *ret = p;
1124         return 0;
1125 }
1126
1127 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1128
1129 int sd_radv_pref64_prefix_set_prefix(
1130                 sd_radv_pref64_prefix *p,
1131                 const struct in6_addr *prefix,
1132                 uint8_t prefixlen,
1133                 uint64_t lifetime_usec) {
1134
1135         uint16_t pref64_lifetime;
1136         uint8_t prefixlen_code;
1137         int r;
1138
1139         assert_return(p, -EINVAL);
1140         assert_return(prefix, -EINVAL);
1141
1142         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1143         if (r < 0)
1144                 return log_radv_errno(NULL, r,
1145                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1146
1147         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1148                 return -EINVAL;
1149
1150         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1151         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1152         pref64_lifetime |= prefixlen_code;
1153
1154         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1155         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1156
1157         p->in6_addr = *prefix;
1158         p->prefixlen = prefixlen;
1159
1160         return 0;
1161 }