src/libsystemd-network/sd-radv.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2017 Intel Corporation. All rights reserved.
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <netinet/icmp6.h>
  21 #include <netinet/in.h>
  22 #include <arpa/inet.h>
  23
  24 #include "sd-radv.h"
  25
  26 #include "macro.h"
  27 #include "alloc-util.h"
  28 #include "fd-util.h"
  29 #include "icmp6-util.h"
  30 #include "in-addr-util.h"
  31 #include "radv-internal.h"
  32 #include "socket-util.h"
  33 #include "string-util.h"
  34 #include "util.h"
  35 #include "random-util.h"
  36
  37 _public_ int sd_radv_new(sd_radv **ret) {
  38         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  39
  40         assert_return(ret, -EINVAL);
  41
  42         ra = new0(sd_radv, 1);
  43         if (!ra)
  44                 return -ENOMEM;
  45
  46         ra->n_ref = 1;
  47
  48         LIST_HEAD_INIT(ra->prefixes);
  49
  50         *ret = ra;
  51         ra = NULL;
  52
  53         return 0;
  54 }
  55
  56 _public_ int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  57         int r;
  58
  59         assert_return(ra, -EINVAL);
  60         assert_return(!ra->event, -EBUSY);
  61
  62         if (event)
  63                 ra->event = sd_event_ref(event);
  64         else {
  65                 r = sd_event_default(&ra->event);
  66                 if (r < 0)
  67                         return 0;
  68         }
  69
  70         ra->event_priority = priority;
  71
  72         return 0;
  73 }
  74
  75 _public_ int sd_radv_detach_event(sd_radv *ra) {
  76
  77         assert_return(ra, -EINVAL);
  78
  79         ra->event = sd_event_unref(ra->event);
  80         return 0;
  81 }
  82
  83 _public_ sd_event *sd_radv_get_event(sd_radv *ra) {
  84         assert_return(ra, NULL);
  85
  86         return ra->event;
  87 }
  88
  89 static void radv_reset(sd_radv *ra) {
  90
  91         ra->timeout_event_source =
  92                 sd_event_source_unref(ra->timeout_event_source);
  93
  94         ra->ra_sent = 0;
  95 }
  96
  97 _public_ sd_radv *sd_radv_ref(sd_radv *ra) {
  98         if (!ra)
  99                 return NULL;
 100
 101         assert(ra->n_ref > 0);
 102         ra->n_ref++;
 103
 104         return ra;
 105 }
 106
 107 _public_ sd_radv *sd_radv_unref(sd_radv *ra) {
 108         if (!ra)
 109                 return NULL;
 110
 111         assert(ra->n_ref > 0);
 112         ra->n_ref--;
 113
 114         if (ra->n_ref > 0)
 115                 return NULL;
 116
 117         while (ra->prefixes) {
 118                 sd_radv_prefix *p = ra->prefixes;
 119
 120                 LIST_REMOVE(prefix, ra->prefixes, p);
 121                 sd_radv_prefix_unref(p);
 122         }
 123
 124         radv_reset(ra);
 125
 126         sd_radv_detach_event(ra);
 127         return mfree(ra);
 128 }
 129
 130 static int radv_send(sd_radv *ra, const struct in6_addr *dst,
 131                      const uint32_t router_lifetime) {
 132
 133         return -ENOSYS;
 134 }
 135
 136 static usec_t radv_compute_timeout(usec_t min, usec_t max) {
 137         assert_return(min <= max, SD_RADV_DEFAULT_MIN_TIMEOUT_USEC);
 138
 139         return min + (random_u32() % (max - min));
 140 }
 141
 142 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 143         int r;
 144         sd_radv *ra = userdata;
 145         usec_t min_timeout = SD_RADV_DEFAULT_MIN_TIMEOUT_USEC;
 146         usec_t max_timeout = SD_RADV_DEFAULT_MAX_TIMEOUT_USEC;
 147         usec_t time_now, timeout;
 148         char time_string[FORMAT_TIMESPAN_MAX];
 149
 150         assert(s);
 151         assert(ra);
 152         assert(ra->event);
 153
 154         ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source);
 155
 156         r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now);
 157         if (r < 0)
 158                 goto fail;
 159
 160         r = radv_send(ra, NULL, ra->lifetime);
 161         if (r < 0)
 162                 log_radv_warning_errno(r, "Unable to send Router Advertisement: %m");
 163
 164         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 165         if (ra->ra_sent < SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS) {
 166                 max_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 167                 min_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC / 3;
 168         }
 169
 170         timeout = radv_compute_timeout(min_timeout, max_timeout);
 171
 172         log_radv("Next Router Advertisement in %s",
 173                  format_timespan(time_string, FORMAT_TIMESPAN_MAX,
 174                                  timeout, USEC_PER_SEC));
 175
 176         r = sd_event_add_time(ra->event, &ra->timeout_event_source,
 177                               clock_boottime_or_monotonic(),
 178                               time_now + timeout, MSEC_PER_SEC,
 179                               radv_timeout, ra);
 180         if (r < 0)
 181                 goto fail;
 182
 183         r = sd_event_source_set_priority(ra->timeout_event_source,
 184                                          ra->event_priority);
 185         if (r < 0)
 186                 goto fail;
 187
 188         r = sd_event_source_set_description(ra->timeout_event_source,
 189                                             "radv-timeout");
 190         if (r < 0)
 191                 goto fail;
 192
 193         ra->ra_sent++;
 194
 195 fail:
 196         if (r < 0)
 197                 sd_radv_stop(ra);
 198
 199         return 0;
 200 }
 201
 202 _public_ int sd_radv_stop(sd_radv *ra) {
 203         int r;
 204
 205         assert_return(ra, -EINVAL);
 206
 207         log_radv("Stopping IPv6 Router Advertisement daemon");
 208
 209         /* RFC 4861, Section 6.2.5, send at least one Router Advertisement
 210            with zero lifetime  */
 211         r = radv_send(ra, NULL, 0);
 212         if (r < 0)
 213                 log_radv_warning_errno(r, "Unable to send last Router Advertisement with router lifetime set to zero: %m");
 214
 215         radv_reset(ra);
 216         ra->state = SD_RADV_STATE_IDLE;
 217
 218         return 0;
 219 }
 220
 221 _public_ int sd_radv_start(sd_radv *ra) {
 222         int r = 0;
 223
 224         assert_return(ra, -EINVAL);
 225         assert_return(ra->event, -EINVAL);
 226         assert_return(ra->ifindex > 0, -EINVAL);
 227
 228         if (ra->state != SD_RADV_STATE_IDLE)
 229                 return 0;
 230
 231         r = sd_event_add_time(ra->event, &ra->timeout_event_source,
 232                               clock_boottime_or_monotonic(), 0, 0,
 233                               radv_timeout, ra);
 234         if (r < 0)
 235                 goto fail;
 236
 237         r = sd_event_source_set_priority(ra->timeout_event_source,
 238                                          ra->event_priority);
 239         if (r < 0)
 240                 goto fail;
 241
 242         (void) sd_event_source_set_description(ra->timeout_event_source,
 243                                                "radv-timeout");
 244
 245         ra->state = SD_RADV_STATE_ADVERTISING;
 246
 247         log_radv("Started IPv6 Router Advertisement daemon");
 248
 249         return 0;
 250
 251  fail:
 252         radv_reset(ra);
 253
 254         return r;
 255 }
 256
 257 _public_ int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 258         assert_return(ra, -EINVAL);
 259         assert_return(ifindex >= -1, -EINVAL);
 260
 261         if (ra->state != SD_RADV_STATE_IDLE)
 262                 return -EBUSY;
 263
 264         ra->ifindex = ifindex;
 265
 266         return 0;
 267 }
 268
 269 _public_ int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 270         assert_return(ra, -EINVAL);
 271
 272         if (ra->state != SD_RADV_STATE_IDLE)
 273                 return -EBUSY;
 274
 275         if (mac_addr)
 276                 ra->mac_addr = *mac_addr;
 277         else
 278                 zero(ra->mac_addr);
 279
 280         return 0;
 281 }
 282
 283 _public_ int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 284         assert_return(ra, -EINVAL);
 285         assert_return(mtu >= 1280, -EINVAL);
 286
 287         if (ra->state != SD_RADV_STATE_IDLE)
 288                 return -EBUSY;
 289
 290         ra->mtu = mtu;
 291
 292         return 0;
 293 }
 294
 295 _public_ int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 296         assert_return(ra, -EINVAL);
 297
 298         if (ra->state != SD_RADV_STATE_IDLE)
 299                 return -EBUSY;
 300
 301         ra->hop_limit = hop_limit;
 302
 303         return 0;
 304 }
 305
 306 _public_ int sd_radv_set_router_lifetime(sd_radv *ra, uint32_t router_lifetime) {
 307         assert_return(ra, -EINVAL);
 308
 309         if (ra->state != SD_RADV_STATE_IDLE)
 310                 return -EBUSY;
 311
 312         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the
 313            preference value MUST be set to (00) by the sender..." */
 314         if (router_lifetime == 0 &&
 315             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 316                 return -ETIME;
 317
 318         ra->lifetime = router_lifetime;
 319
 320         return 0;
 321 }
 322
 323 _public_ int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 324         assert_return(ra, -EINVAL);
 325
 326         if (ra->state != SD_RADV_STATE_IDLE)
 327                 return -EBUSY;
 328
 329         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 330
 331         return 0;
 332 }
 333
 334 _public_ int sd_radv_set_other_information(sd_radv *ra, int other) {
 335         assert_return(ra, -EINVAL);
 336
 337         if (ra->state != SD_RADV_STATE_IDLE)
 338                 return -EBUSY;
 339
 340         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 341
 342         return 0;
 343 }
 344
 345 _public_ int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 346         int r = 0;
 347
 348         assert_return(ra, -EINVAL);
 349         assert_return(IN_SET(preference,
 350                              SD_NDISC_PREFERENCE_LOW,
 351                              SD_NDISC_PREFERENCE_MEDIUM,
 352                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 353
 354         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 355
 356         return r;
 357 }
 358
 359 _public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 360         sd_radv_prefix *cur;
 361         _cleanup_free_ char *addr_p = NULL;
 362
 363         assert_return(ra, -EINVAL);
 364
 365         if (!p)
 366                 return -EINVAL;
 367
 368         LIST_FOREACH(prefix, cur, ra->prefixes) {
 369                 int r;
 370
 371                 r = in_addr_prefix_intersect(AF_INET6,
 372                                              (union in_addr_union*) &cur->opt.in6_addr,
 373                                              cur->opt.prefixlen,
 374                                              (union in_addr_union*) &p->opt.in6_addr,
 375                                              p->opt.prefixlen);
 376                 if (r > 0) {
 377                         _cleanup_free_ char *addr_cur = NULL;
 378
 379                         (void) in_addr_to_string(AF_INET6,
 380                                                  (union in_addr_union*) &cur->opt.in6_addr,
 381                                                  &addr_cur);
 382                         (void) in_addr_to_string(AF_INET6,
 383                                                  (union in_addr_union*) &p->opt.in6_addr,
 384                                                  &addr_p);
 385
 386                         log_radv("IPv6 prefix %s/%u already configured, ignoring %s/%u",
 387                                  addr_cur, cur->opt.prefixlen,
 388                                  addr_p, p->opt.prefixlen);
 389
 390                         return -EEXIST;
 391                 }
 392         }
 393
 394         p = sd_radv_prefix_ref(p);
 395
 396         LIST_APPEND(prefix, ra->prefixes, p);
 397
 398         ra->n_prefixes++;
 399
 400         (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &p->opt.in6_addr, &addr_p);
 401         log_radv("Added prefix %s/%d", addr_p, p->opt.prefixlen);
 402
 403         return 0;
 404 }
 405
 406 _public_ int sd_radv_prefix_new(sd_radv_prefix **ret) {
 407         _cleanup_(sd_radv_prefix_unrefp) sd_radv_prefix *p = NULL;
 408
 409         assert_return(ret, -EINVAL);
 410
 411         p = new0(sd_radv_prefix, 1);
 412         if (!p)
 413                 return -ENOMEM;
 414
 415         p->n_ref = 1;
 416
 417         p->opt.type = ND_OPT_PREFIX_INFORMATION;
 418         p->opt.length = (sizeof(p->opt) - 1) /8 + 1;
 419
 420         p->opt.prefixlen = 64;
 421
 422         /* RFC 4861, Section 6.2.1 */
 423         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, true);
 424         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, true);
 425         p->opt.preferred_lifetime = htobe32(604800);
 426         p->opt.valid_lifetime = htobe32(2592000);
 427
 428         LIST_INIT(prefix, p);
 429
 430         *ret = p;
 431         p = NULL;
 432
 433         return 0;
 434 }
 435
 436 _public_ sd_radv_prefix *sd_radv_prefix_ref(sd_radv_prefix *p) {
 437         if (!p)
 438                 return NULL;
 439
 440         assert(p->n_ref > 0);
 441         p->n_ref++;
 442
 443         return p;
 444 }
 445
 446 _public_ sd_radv_prefix *sd_radv_prefix_unref(sd_radv_prefix *p) {
 447         if (!p)
 448                 return NULL;
 449
 450         assert(p->n_ref > 0);
 451         p->n_ref--;
 452
 453         if (p->n_ref > 0)
 454                 return NULL;
 455
 456         return mfree(p);
 457 }
 458
 459 _public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, struct in6_addr *in6_addr,
 460                                        unsigned char prefixlen) {
 461         assert_return(p, -EINVAL);
 462         assert_return(in6_addr, -EINVAL);
 463
 464         if (prefixlen < 3 || prefixlen > 128)
 465                 return -EINVAL;
 466
 467         if (prefixlen > 64)
 468                 /* unusual but allowed, log it */
 469                 log_radv("Unusual prefix length %d greater than 64", prefixlen);
 470
 471         p->opt.in6_addr = *in6_addr;
 472         p->opt.prefixlen = prefixlen;
 473
 474         return 0;
 475 }
 476
 477 _public_ int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
 478         assert_return(p, -EINVAL);
 479
 480         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
 481
 482         return 0;
 483 }
 484
 485 _public_ int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,
 486                                                           int address_autoconfiguration) {
 487         assert_return(p, -EINVAL);
 488
 489         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
 490
 491         return 0;
 492 }
 493
 494 _public_ int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p,
 495                                                uint32_t valid_lifetime) {
 496         assert_return(p, -EINVAL);
 497
 498         p->opt.valid_lifetime = htobe32(valid_lifetime);
 499
 500         return 0;
 501 }
 502
 503 _public_ int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p,
 504                                                    uint32_t preferred_lifetime) {
 505         assert_return(p, -EINVAL);
 506
 507         p->opt.preferred_lifetime = htobe32(preferred_lifetime);
 508
 509         return 0;
 510 }