src/router.c

   1 /**
   2  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2018 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <signal.h>
  19 #include <resolv.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <stdbool.h>
  24 #include <arpa/inet.h>
  25 #include <net/route.h>
  26
  27 #include <libubox/utils.h>
  28
  29 #include "router.h"
  30 #include "odhcpd.h"
  31
  32
  33 static void forward_router_solicitation(const struct interface *iface);
  34 static void forward_router_advertisement(const struct interface *iface, uint8_t *data, size_t len);
  35
  36 static void handle_icmpv6(void *addr, void *data, size_t len,
  37                 struct interface *iface, void *dest);
  38 static void trigger_router_advert(struct uloop_timeout *event);
  39 static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info);
  40
  41 static struct netevent_handler router_netevent_handler = { .cb = router_netevent_cb, };
  42
  43 static FILE *fp_route = NULL;
  44
  45
  46 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
  47
  48 int router_init(void)
  49 {
  50         int ret = 0;
  51
  52         if (!(fp_route = fopen("/proc/net/ipv6_route", "r"))) {
  53                 syslog(LOG_ERR, "fopen(/proc/net/ipv6_route): %m");
  54                 ret = -1;
  55                 goto out;
  56         }
  57
  58         if (netlink_add_netevent_handler(&router_netevent_handler) < 0) {
  59                 syslog(LOG_ERR, "Failed to add netevent handler");
  60                 ret = -1;
  61         }
  62
  63 out:
  64         if (ret < 0 && fp_route) {
  65                 fclose(fp_route);
  66                 fp_route = NULL;
  67         }
  68
  69         return ret;
  70 }
  71
  72
  73 int router_setup_interface(struct interface *iface, bool enable)
  74 {
  75         int ret = 0;
  76
  77         enable = enable && (iface->ra != MODE_DISABLED);
  78
  79         if (!fp_route) {
  80                 ret = -1;
  81                 goto out;
  82         }
  83
  84
  85         if (!enable && iface->router_event.uloop.fd >= 0) {
  86                 if (!iface->master) {
  87                         uloop_timeout_cancel(&iface->timer_rs);
  88                         iface->timer_rs.cb = NULL;
  89
  90                         trigger_router_advert(&iface->timer_rs);
  91                 }
  92
  93                 uloop_fd_delete(&iface->router_event.uloop);
  94                 close(iface->router_event.uloop.fd);
  95                 iface->router_event.uloop.fd = -1;
  96         } else if (enable) {
  97                 struct icmp6_filter filt;
  98                 struct ipv6_mreq mreq;
  99                 int val = 2;
 100
 101                 if (iface->router_event.uloop.fd < 0) {
 102                         /* Open ICMPv6 socket */
 103                         iface->router_event.uloop.fd = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC,
 104                                                               IPPROTO_ICMPV6);
 105                         if (iface->router_event.uloop.fd < 0) {
 106                                 syslog(LOG_ERR, "socket(AF_INET6): %m");
 107                                 ret = -1;
 108                                 goto out;
 109                         }
 110
 111                         if (setsockopt(iface->router_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
 112                                        iface->ifname, strlen(iface->ifname)) < 0) {
 113                                 syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
 114                                 ret = -1;
 115                                 goto out;
 116                         }
 117
 118                         /* Let the kernel compute our checksums */
 119                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_RAW, IPV6_CHECKSUM,
 120                                        &val, sizeof(val)) < 0) {
 121                                 syslog(LOG_ERR, "setsockopt(IPV6_CHECKSUM): %m");
 122                                 ret = -1;
 123                                 goto out;
 124                         }
 125
 126                         /* This is required by RFC 4861 */
 127                         val = 255;
 128                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
 129                                        &val, sizeof(val)) < 0) {
 130                                 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m");
 131                                 ret = -1;
 132                                 goto out;
 133                         }
 134
 135                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS,
 136                                        &val, sizeof(val)) < 0) {
 137                                 syslog(LOG_ERR, "setsockopt(IPV6_UNICAST_HOPS): %m");
 138                                 ret = -1;
 139                                 goto out;
 140                         }
 141
 142                         /* We need to know the source interface */
 143                         val = 1;
 144                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
 145                                        &val, sizeof(val)) < 0) {
 146                                 syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m");
 147                                 ret = -1;
 148                                 goto out;
 149                         }
 150
 151                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
 152                                        &val, sizeof(val)) < 0) {
 153                                 syslog(LOG_ERR, "setsockopt(IPV6_RECVHOPLIMIT): %m");
 154                                 ret = -1;
 155                                 goto out;
 156                         }
 157
 158                         /* Don't loop back */
 159                         val = 0;
 160                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
 161                                        &val, sizeof(val)) < 0) {
 162                                 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m");
 163                                 ret = -1;
 164                                 goto out;
 165                         }
 166
 167                         /* Filter ICMPv6 package types */
 168                         ICMP6_FILTER_SETBLOCKALL(&filt);
 169                         ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
 170                         ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
 171                         if (setsockopt(iface->router_event.uloop.fd, IPPROTO_ICMPV6, ICMP6_FILTER,
 172                                        &filt, sizeof(filt)) < 0) {
 173                                 syslog(LOG_ERR, "setsockopt(ICMP6_FILTER): %m");
 174                                 ret = -1;
 175                                 goto out;
 176                         }
 177
 178                         iface->router_event.handle_dgram = handle_icmpv6;
 179                         odhcpd_register(&iface->router_event);
 180                 } else {
 181                         uloop_timeout_cancel(&iface->timer_rs);
 182                         iface->timer_rs.cb = NULL;
 183
 184                         memset(&mreq, 0, sizeof(mreq));
 185                         mreq.ipv6mr_interface = iface->ifindex;
 186                         inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr);
 187                         setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 188                                    &mreq, sizeof(mreq));
 189
 190                         inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &mreq.ipv6mr_multiaddr);
 191                         setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 192                                    &mreq, sizeof(mreq));
 193                 }
 194
 195                 memset(&mreq, 0, sizeof(mreq));
 196                 mreq.ipv6mr_interface = iface->ifindex;
 197                 inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &mreq.ipv6mr_multiaddr);
 198
 199                 if (iface->ra == MODE_RELAY && iface->master) {
 200                         inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr);
 201                         forward_router_solicitation(iface);
 202                 } else if (iface->ra == MODE_SERVER) {
 203                         iface->timer_rs.cb = trigger_router_advert;
 204                         uloop_timeout_set(&iface->timer_rs, 1000);
 205                 }
 206
 207                 if (setsockopt(iface->router_event.uloop.fd, IPPROTO_IPV6,
 208                                IPV6_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
 209                         ret = -1;
 210                         syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
 211                         goto out;
 212                 }
 213         }
 214 out:
 215         if (ret < 0 && iface->router_event.uloop.fd >= 0) {
 216                 if (iface->router_event.uloop.registered)
 217                         uloop_fd_delete(&iface->router_event.uloop);
 218
 219                 close(iface->router_event.uloop.fd);
 220                 iface->router_event.uloop.fd = -1;
 221         }
 222
 223         return ret;
 224 }
 225
 226
 227 static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 228 {
 229         struct interface *iface;
 230
 231         switch (event) {
 232         case NETEV_IFINDEX_CHANGE:
 233                 iface = info->iface;
 234                 if (iface && iface->router_event.uloop.fd >= 0) {
 235                         if (iface->router_event.uloop.registered)
 236                                 uloop_fd_delete(&iface->router_event.uloop);
 237
 238                         close(iface->router_event.uloop.fd);
 239                         iface->router_event.uloop.fd = -1;
 240                 }
 241                 break;
 242         case NETEV_ROUTE6_ADD:
 243         case NETEV_ROUTE6_DEL:
 244                 if (info->rt.dst_len)
 245                         break;
 246
 247                 avl_for_each_element(&interfaces, iface, avl) {
 248                         if (iface->ra == MODE_SERVER && !iface->master)
 249                                 uloop_timeout_set(&iface->timer_rs, 1000);
 250                 }
 251                 break;
 252         case NETEV_ADDR6LIST_CHANGE:
 253                 iface = info->iface;
 254                 if (iface && iface->ra == MODE_SERVER && !iface->master)
 255                         uloop_timeout_set(&iface->timer_rs, 1000);
 256                 break;
 257         default:
 258                 break;
 259         }
 260 }
 261
 262
 263 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
 264 {
 265         struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
 266         struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
 267
 268         /* Hoplimit is already checked in odhcpd_receive_packets */
 269         if (len < sizeof(*hdr) || hdr->icmp6_code)
 270                 return false;
 271
 272         switch (hdr->icmp6_type) {
 273         case ND_ROUTER_ADVERT:
 274                 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
 275                         return false;
 276
 277                 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
 278                 break;
 279
 280         case ND_ROUTER_SOLICIT:
 281                 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
 282                 break;
 283
 284         default:
 285                 return false;
 286         }
 287
 288         icmpv6_for_each_option(opt, opt, end)
 289                 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
 290                                 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
 291                                 hdr->icmp6_type == ND_ROUTER_SOLICIT)
 292                         return false;
 293
 294         /* Check all options parsed successfully */
 295         return opt == end;
 296 }
 297
 298
 299 /* Detect whether a default route exists, also find the source prefixes */
 300 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 301 {
 302         struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0,
 303                                         .dprefix = 0, .preferred = 0, .valid = 0};
 304         bool found_default = false;
 305         char line[512], ifname[16];
 306
 307         rewind(fp_route);
 308
 309         while (fgets(line, sizeof(line), fp_route)) {
 310                 uint32_t rflags;
 311                 if (sscanf(line, "00000000000000000000000000000000 00 "
 312                                 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
 313                                 strcmp(ifname, "lo")) {
 314                         found_default = true;
 315                 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
 316                                 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
 317                                 &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) &&
 318                                 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
 319                         // Find source prefixes by scanning through unreachable-routes
 320                         p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]);
 321                         p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]);
 322
 323                         for (ssize_t i = 0; i < len; ++i) {
 324                                 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
 325                                                 !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) {
 326                                         n[i].dprefix = p.prefix;
 327                                         break;
 328                                 }
 329                         }
 330                 }
 331         }
 332
 333         return found_default;
 334 }
 335
 336 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
 337                              uint32_t *maxival)
 338 {
 339         uint32_t minival = iface->ra_mininterval;
 340         int msecs;
 341
 342         *maxival = iface->ra_maxinterval;
 343
 344         if (*maxival > minvalid/3)
 345                 *maxival = minvalid/3;
 346
 347         if (*maxival > MaxRtrAdvInterval)
 348                 *maxival = MaxRtrAdvInterval;
 349         else if (*maxival < 4)
 350                 *maxival = 4;
 351
 352         if (minival < MinRtrAdvInterval)
 353                 minival = MinRtrAdvInterval;
 354         else if (minival > (*maxival * 3)/4)
 355                 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
 356
 357         odhcpd_urandom(&msecs, sizeof(msecs));
 358         msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
 359                         minival*1000;
 360
 361         return msecs;
 362 }
 363
 364 static uint32_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
 365 {
 366         uint32_t lifetime = 3*maxival;
 367
 368         if (iface->ra_lifetime >= 0) {
 369                 lifetime = iface->ra_lifetime;
 370                 if (lifetime > 0 && lifetime < maxival)
 371                         lifetime = maxival;
 372                 else if (lifetime > 9000)
 373                         lifetime = 9000;
 374         }
 375
 376         return lifetime;
 377 }
 378
 379 enum {
 380         IOV_RA_ADV=0,
 381         IOV_RA_PFXS,
 382         IOV_RA_ROUTES,
 383         IOV_RA_DNS,
 384         IOV_RA_SEARCH,
 385         IOV_RA_ADV_INTERVAL,
 386         IOV_RA_TOTAL,
 387 };
 388
 389 struct adv_msg {
 390         struct nd_router_advert h;
 391         struct icmpv6_opt lladdr;
 392         struct nd_opt_mtu mtu;
 393 };
 394
 395 struct nd_opt_dns_server {
 396         uint8_t type;
 397         uint8_t len;
 398         uint8_t pad;
 399         uint8_t pad2;
 400         uint32_t lifetime;
 401         struct in6_addr addr[];
 402 };
 403
 404 struct nd_opt_search_list {
 405         uint8_t type;
 406         uint8_t len;
 407         uint8_t pad;
 408         uint8_t pad2;
 409         uint32_t lifetime;
 410         uint8_t name[];
 411 };
 412
 413 struct nd_opt_route_info {
 414         uint8_t type;
 415         uint8_t len;
 416         uint8_t prefix;
 417         uint8_t flags;
 418         uint32_t lifetime;
 419         uint32_t addr[4];
 420 };
 421
 422 /* Router Advert server mode */
 423 static int send_router_advert(struct interface *iface, const struct in6_addr *from)
 424 {
 425         time_t now = odhcpd_time();
 426         struct odhcpd_ipaddr *addrs = NULL;
 427         struct adv_msg adv;
 428         struct nd_opt_prefix_info *pfxs = NULL;
 429         struct nd_opt_dns_server *dns = NULL;
 430         struct nd_opt_search_list *search = NULL;
 431         struct nd_opt_route_info *routes = NULL;
 432         struct nd_opt_adv_interval adv_interval;
 433         struct iovec iov[IOV_RA_TOTAL];
 434         struct sockaddr_in6 dest;
 435         size_t dns_sz = 0, search_sz = 0, pfxs_cnt = 0, routes_cnt = 0;
 436         ssize_t addr_cnt = 0;
 437         uint32_t minvalid = UINT32_MAX, maxival, lifetime;
 438         int msecs, mtu = iface->ra_mtu, hlim = iface->ra_hoplimit;
 439         bool default_route = false;
 440         bool valid_prefix = false;
 441         char buf[INET6_ADDRSTRLEN];
 442
 443         memset(&adv, 0, sizeof(adv));
 444         adv.h.nd_ra_type = ND_ROUTER_ADVERT;
 445
 446         if (hlim == 0)
 447                 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
 448
 449         if (hlim > 0)
 450                 adv.h.nd_ra_curhoplimit = hlim;
 451
 452         adv.h.nd_ra_flags_reserved = iface->ra_flags;
 453
 454         if (iface->route_preference < 0)
 455                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 456         else if (iface->route_preference > 0)
 457                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
 458
 459         adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
 460         adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
 461
 462         adv.lladdr.type = ND_OPT_SOURCE_LINKADDR;
 463         adv.lladdr.len = 1;
 464         odhcpd_get_mac(iface, adv.lladdr.data);
 465
 466         adv.mtu.nd_opt_mtu_type = ND_OPT_MTU;
 467         adv.mtu.nd_opt_mtu_len = 1;
 468
 469         if (mtu == 0)
 470                 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
 471
 472         if (mtu < 1280)
 473                 mtu = 1280;
 474
 475         adv.mtu.nd_opt_mtu_mtu = htonl(mtu);
 476
 477         iov[IOV_RA_ADV].iov_base = (char *)&adv;
 478         iov[IOV_RA_ADV].iov_len = sizeof(adv);
 479
 480         /* If not shutdown */
 481         if (iface->timer_rs.cb) {
 482                 size_t size = sizeof(*addrs) * iface->addr6_len;
 483
 484                 addrs = alloca(size);
 485                 memcpy(addrs, iface->addr6, size);
 486
 487                 addr_cnt = iface->addr6_len;
 488
 489                 /* Check default route */
 490                 if (iface->default_router) {
 491                         default_route = true;
 492
 493                         if (iface->default_router > 1)
 494                                 valid_prefix = true;
 495                 } else if (parse_routes(addrs, addr_cnt))
 496                         default_route = true;
 497         }
 498
 499         /* Construct Prefix Information options */
 500         for (ssize_t i = 0; i < addr_cnt; ++i) {
 501                 struct odhcpd_ipaddr *addr = &addrs[i];
 502                 struct nd_opt_prefix_info *p = NULL;
 503                 uint32_t preferred = 0;
 504                 uint32_t valid = 0;
 505
 506                 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
 507                         syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
 508                                 inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)), addr->prefix,
 509                                 addr->valid, iface->name);
 510                         continue;
 511                 }
 512
 513                 if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
 514                                    iface->pio_filter_length) != 0 ||
 515                     addr->prefix < iface->pio_filter_length) {
 516                         syslog(LOG_INFO, "Address %s filtered out as RA prefix on %s",
 517                                inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 518                                iface->name);
 519                         continue; /* PIO filtered out of this RA */
 520                 }
 521
 522                 for (size_t i = 0; i < pfxs_cnt; ++i) {
 523                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
 524                                         !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 525                                         &addr->addr.in6, addr->prefix))
 526                                 p = &pfxs[i];
 527                 }
 528
 529                 if (!p) {
 530                         struct nd_opt_prefix_info *tmp;
 531
 532                         tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
 533                         if (!tmp) {
 534                                 syslog(LOG_ERR, "Realloc failed for RA prefix option on %s", iface->name);
 535                                 continue;
 536                         }
 537
 538                         pfxs = tmp;
 539                         p = &pfxs[pfxs_cnt++];
 540                         memset(p, 0, sizeof(*p));
 541                 }
 542
 543                 if (addr->preferred > (uint32_t)now) {
 544                         preferred = TIME_LEFT(addr->preferred, now);
 545
 546                         if (iface->ra_useleasetime &&
 547                                         preferred > iface->dhcpv4_leasetime)
 548                                 preferred = iface->dhcpv4_leasetime;
 549                 }
 550
 551                 valid = TIME_LEFT(addr->valid, now);
 552                 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
 553                         valid = iface->dhcpv4_leasetime;
 554
 555                 if (minvalid > valid)
 556                         minvalid = valid;
 557
 558                 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
 559                         valid_prefix = true;
 560
 561                 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr.in6,
 562                                 (iface->ra_advrouter) ? 128 : addr->prefix);
 563                 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 564                 p->nd_opt_pi_len = 4;
 565                 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 566                 p->nd_opt_pi_flags_reserved = 0;
 567                 if (!iface->ra_not_onlink)
 568                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
 569                 if (iface->ra_slaac && addr->prefix <= 64)
 570                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 571                 if (iface->ra_advrouter)
 572                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
 573                 p->nd_opt_pi_preferred_time = htonl(preferred);
 574                 p->nd_opt_pi_valid_time = htonl(valid);
 575         }
 576
 577         iov[IOV_RA_PFXS].iov_base = (char *)pfxs;
 578         iov[IOV_RA_PFXS].iov_len = pfxs_cnt * sizeof(*pfxs);
 579
 580         /* Calculate periodic transmit */
 581         msecs = calc_adv_interval(iface, minvalid, &maxival);
 582         lifetime = calc_ra_lifetime(iface, maxival);
 583
 584         if (default_route) {
 585                 if (!valid_prefix) {
 586                         syslog(LOG_WARNING, "A default route is present but there is no public prefix "
 587                                         "on %s thus we don't announce a default route!", iface->name);
 588                         adv.h.nd_ra_router_lifetime = 0;
 589                 } else
 590                         adv.h.nd_ra_router_lifetime = htons(lifetime < UINT16_MAX ? lifetime : UINT16_MAX);
 591
 592         } else
 593                 adv.h.nd_ra_router_lifetime = 0;
 594
 595         syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->name);
 596
 597         /* DNS options */
 598         if (iface->ra_dns) {
 599                 struct in6_addr dns_pref, *dns_addr = NULL;
 600                 size_t dns_cnt = 0, search_len = iface->search_len;
 601                 uint8_t *search_domain = iface->search;
 602
 603                 /* DNS Recursive DNS */
 604                 if (iface->dns_cnt > 0) {
 605                         dns_addr = iface->dns;
 606                         dns_cnt = iface->dns_cnt;
 607                 } else if (!odhcpd_get_interface_dns_addr(iface, &dns_pref)) {
 608                         dns_addr = &dns_pref;
 609                         dns_cnt = 1;
 610                 }
 611
 612                 if (dns_cnt) {
 613                         dns_sz = sizeof(*dns) + sizeof(struct in6_addr)*dns_cnt;
 614
 615                         dns = alloca(dns_sz);
 616                         memset(dns, 0, dns_sz);
 617                         dns->type = ND_OPT_RECURSIVE_DNS;
 618                         dns->len = 1 + (2 * dns_cnt);
 619                         dns->lifetime = htonl(lifetime);
 620                         memcpy(dns->addr, dns_addr, sizeof(struct in6_addr)*dns_cnt);
 621                 }
 622
 623                 /* DNS Search options */
 624                 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 625                         uint8_t search_buf[256];
 626
 627                         int len = dn_comp(_res.dnsrch[0], search_buf,
 628                                         sizeof(search_buf), NULL, NULL);
 629                         if (len > 0) {
 630                                 search_domain = search_buf;
 631                                 search_len = len;
 632                         }
 633                 }
 634
 635                 if (search_len > 0) {
 636                         size_t search_padded = ((search_len + 7) & (~7)) + 8;
 637
 638                         search_sz = sizeof(*search) + search_padded;
 639
 640                         search = alloca(search_sz);
 641                         memset(search, 0, search_sz);
 642                         search->type = ND_OPT_DNS_SEARCH;
 643                         search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
 644                         search->lifetime = htonl(lifetime);
 645                         memcpy(search->name, search_domain, search_len);
 646                         memset(&search->name[search_len], 0, search_padded - search_len);
 647                 }
 648         }
 649
 650         iov[IOV_RA_DNS].iov_base = (char *)dns;
 651         iov[IOV_RA_DNS].iov_len = dns_sz;
 652         iov[IOV_RA_SEARCH].iov_base = (char *)search;
 653         iov[IOV_RA_SEARCH].iov_len = search_sz;
 654
 655         for (ssize_t i = 0; i < addr_cnt; ++i) {
 656                 struct odhcpd_ipaddr *addr = &addrs[i];
 657                 struct nd_opt_route_info *tmp;
 658                 uint32_t valid;
 659
 660                 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now) {
 661                         syslog(LOG_INFO, "Address %s (dprefix %d, valid %u) not suitable as RA route on %s",
 662                                 inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 663                                 addr->dprefix, addr->valid, iface->name);
 664
 665                         continue; /* Address not suitable */
 666                 }
 667
 668                 if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
 669                                 iface->pio_filter_length) != 0 ||
 670                                 addr->prefix < iface->pio_filter_length) {
 671                         syslog(LOG_INFO, "Address %s filtered out as RA route on %s",
 672                                inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 673                                iface->name);
 674                         continue; /* PIO filtered out of this RA */
 675                 }
 676
 677                 if (addr->dprefix > 32) {
 678                         addr->addr.in6.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
 679                 } else if (addr->dprefix <= 32) {
 680                         addr->addr.in6.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
 681                         addr->addr.in6.s6_addr32[1] = 0;
 682                 }
 683
 684                 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
 685                 if (!tmp) {
 686                         syslog(LOG_ERR, "Realloc failed for RA route option on %s", iface->name);
 687                         continue;
 688                 }
 689
 690                 routes = tmp;
 691
 692                 memset(&routes[routes_cnt], 0, sizeof(*routes));
 693                 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 694                 routes[routes_cnt].len = sizeof(*routes) / 8;
 695                 routes[routes_cnt].prefix = addr->dprefix;
 696                 routes[routes_cnt].flags = 0;
 697                 if (iface->route_preference < 0)
 698                         routes[routes_cnt].flags |= ND_RA_PREF_LOW;
 699                 else if (iface->route_preference > 0)
 700                         routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
 701
 702                 valid = TIME_LEFT(addr->valid, now);
 703                 routes[routes_cnt].lifetime = htonl(valid < lifetime ? valid : lifetime);
 704                 routes[routes_cnt].addr[0] = addr->addr.in6.s6_addr32[0];
 705                 routes[routes_cnt].addr[1] = addr->addr.in6.s6_addr32[1];
 706                 routes[routes_cnt].addr[2] = 0;
 707                 routes[routes_cnt].addr[3] = 0;
 708
 709                 ++routes_cnt;
 710         }
 711
 712         iov[IOV_RA_ROUTES].iov_base = (char *)routes;
 713         iov[IOV_RA_ROUTES].iov_len = routes_cnt * sizeof(*routes);
 714
 715         memset(&adv_interval, 0, sizeof(adv_interval));
 716         adv_interval.nd_opt_adv_interval_type = ND_OPT_RTR_ADV_INTERVAL;
 717         adv_interval.nd_opt_adv_interval_len = 1;
 718         adv_interval.nd_opt_adv_interval_ival = htonl(maxival);
 719
 720         iov[IOV_RA_ADV_INTERVAL].iov_base = (char *)&adv_interval;
 721         iov[IOV_RA_ADV_INTERVAL].iov_len = adv_interval.nd_opt_adv_interval_len * 8;
 722
 723         memset(&dest, 0, sizeof(dest));
 724         dest.sin6_family = AF_INET6;
 725
 726         if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
 727                 dest.sin6_addr = *from;
 728         else
 729                 inet_pton(AF_INET6, ALL_IPV6_NODES, &dest.sin6_addr);
 730
 731         syslog(LOG_NOTICE, "Sending a RA on %s", iface->name);
 732
 733         odhcpd_send(iface->router_event.uloop.fd, &dest, iov, ARRAY_SIZE(iov), iface);
 734
 735         free(pfxs);
 736         free(routes);
 737
 738         return msecs;
 739 }
 740
 741
 742 static void trigger_router_advert(struct uloop_timeout *event)
 743 {
 744         struct interface *iface = container_of(event, struct interface, timer_rs);
 745         int msecs = send_router_advert(iface, NULL);
 746
 747         /* Rearm timer if not shut down */
 748         if (event->cb)
 749                 uloop_timeout_set(event, msecs);
 750 }
 751
 752
 753 /* Event handler for incoming ICMPv6 packets */
 754 static void handle_icmpv6(void *addr, void *data, size_t len,
 755                 struct interface *iface, _unused void *dest)
 756 {
 757         struct icmp6_hdr *hdr = data;
 758         struct sockaddr_in6 *from = addr;
 759
 760         if (!router_icmpv6_valid(addr, data, len))
 761                 return;
 762
 763         if ((iface->ra == MODE_SERVER && !iface->master)) { /* Server mode */
 764                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
 765                         send_router_advert(iface, &from->sin6_addr);
 766         } else if (iface->ra == MODE_RELAY) { /* Relay mode */
 767                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master) {
 768                         struct interface *c;
 769
 770                         avl_for_each_element(&interfaces, c, avl) {
 771                                 if (!c->master || c->ra != MODE_RELAY)
 772                                         continue;
 773
 774                                 forward_router_solicitation(c);
 775                         }
 776                 } else if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
 777                         forward_router_advertisement(iface, data, len);
 778         }
 779 }
 780
 781
 782 /* Forward router solicitation */
 783 static void forward_router_solicitation(const struct interface *iface)
 784 {
 785         struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
 786         struct iovec iov = {&rs, sizeof(rs)};
 787         struct sockaddr_in6 all_routers;
 788
 789         if (!iface)
 790                 return;
 791
 792         memset(&all_routers, 0, sizeof(all_routers));
 793         all_routers.sin6_family = AF_INET6;
 794         inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &all_routers.sin6_addr);
 795         all_routers.sin6_scope_id = iface->ifindex;
 796
 797         syslog(LOG_NOTICE, "Sending RS to %s", iface->name);
 798         odhcpd_send(iface->router_event.uloop.fd, &all_routers, &iov, 1, iface);
 799 }
 800
 801
 802 /* Handler for incoming router solicitations on slave interfaces */
 803 static void forward_router_advertisement(const struct interface *iface, uint8_t *data, size_t len)
 804 {
 805         struct nd_router_advert *adv = (struct nd_router_advert *)data;
 806         struct sockaddr_in6 all_nodes;
 807         struct icmpv6_opt *opt;
 808         struct interface *c;
 809         struct iovec iov = { .iov_base = data, .iov_len = len };
 810         /* Rewrite options */
 811         uint8_t *end = data + len;
 812         uint8_t *mac_ptr = NULL;
 813         struct in6_addr *dns_ptr = NULL;
 814         size_t dns_count = 0;
 815
 816         icmpv6_for_each_option(opt, &adv[1], end) {
 817                 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 818                         /* Store address of source MAC-address */
 819                         mac_ptr = opt->data;
 820                 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
 821                         /* Check if we have to rewrite DNS */
 822                         dns_ptr = (struct in6_addr*)&opt->data[6];
 823                         dns_count = (opt->len - 1) / 2;
 824                 }
 825         }
 826
 827         syslog(LOG_NOTICE, "Got a RA on %s", iface->name);
 828
 829         /* Indicate a proxy, however we don't follow the rest of RFC 4389 yet */
 830         adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
 831
 832         /* Forward advertisement to all slave interfaces */
 833         memset(&all_nodes, 0, sizeof(all_nodes));
 834         all_nodes.sin6_family = AF_INET6;
 835         inet_pton(AF_INET6, ALL_IPV6_NODES, &all_nodes.sin6_addr);
 836
 837         avl_for_each_element(&interfaces, c, avl) {
 838                 if (c->ra != MODE_RELAY || c->master)
 839                         continue;
 840
 841                 /* Fixup source hardware address option */
 842                 if (mac_ptr)
 843                         odhcpd_get_mac(c, mac_ptr);
 844
 845                 /* If we have to rewrite DNS entries */
 846                 if (c->always_rewrite_dns && dns_ptr && dns_count > 0) {
 847                         const struct in6_addr *rewrite = c->dns;
 848                         struct in6_addr addr;
 849                         size_t rewrite_cnt = c->dns_cnt;
 850
 851                         if (rewrite_cnt == 0) {
 852                                 if (odhcpd_get_interface_dns_addr(c, &addr))
 853                                         continue; /* Unable to comply */
 854
 855                                 rewrite = &addr;
 856                                 rewrite_cnt = 1;
 857                         }
 858
 859                         /* Copy over any other addresses */
 860                         for (size_t i = 0; i < dns_count; ++i) {
 861                                 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
 862                                 dns_ptr[i] = rewrite[j];
 863                         }
 864                 }
 865
 866                 syslog(LOG_NOTICE, "Forward a RA on %s", c->name);
 867
 868                 odhcpd_send(c->router_event.uloop.fd, &all_nodes, &iov, 1, c);
 869         }
 870 }