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                         close(iface->router_event.uloop.fd);
 236                         iface->router_event.uloop.fd = -1;
 237                 }
 238                 break;
 239         case NETEV_ROUTE6_ADD:
 240         case NETEV_ROUTE6_DEL:
 241                 if (info->rt.dst_len)
 242                         break;
 243
 244                 avl_for_each_element(&interfaces, iface, avl) {
 245                         if (iface->ra == MODE_SERVER && !iface->master)
 246                                 uloop_timeout_set(&iface->timer_rs, 1000);
 247                 }
 248                 break;
 249         case NETEV_ADDR6LIST_CHANGE:
 250                 iface = info->iface;
 251                 if (iface && iface->ra == MODE_SERVER && !iface->master)
 252                         uloop_timeout_set(&iface->timer_rs, 1000);
 253                 break;
 254         default:
 255                 break;
 256         }
 257 }
 258
 259
 260 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
 261 {
 262         struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
 263         struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
 264
 265         /* Hoplimit is already checked in odhcpd_receive_packets */
 266         if (len < sizeof(*hdr) || hdr->icmp6_code)
 267                 return false;
 268
 269         switch (hdr->icmp6_type) {
 270         case ND_ROUTER_ADVERT:
 271                 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
 272                         return false;
 273
 274                 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
 275                 break;
 276
 277         case ND_ROUTER_SOLICIT:
 278                 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
 279                 break;
 280
 281         default:
 282                 return false;
 283         }
 284
 285         icmpv6_for_each_option(opt, opt, end)
 286                 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
 287                                 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
 288                                 hdr->icmp6_type == ND_ROUTER_SOLICIT)
 289                         return false;
 290
 291         /* Check all options parsed successfully */
 292         return opt == end;
 293 }
 294
 295
 296 /* Detect whether a default route exists, also find the source prefixes */
 297 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 298 {
 299         struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0,
 300                                         .dprefix = 0, .preferred = 0, .valid = 0};
 301         bool found_default = false;
 302         char line[512], ifname[16];
 303
 304         rewind(fp_route);
 305
 306         while (fgets(line, sizeof(line), fp_route)) {
 307                 uint32_t rflags;
 308                 if (sscanf(line, "00000000000000000000000000000000 00 "
 309                                 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
 310                                 strcmp(ifname, "lo")) {
 311                         found_default = true;
 312                 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
 313                                 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
 314                                 &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) &&
 315                                 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
 316                         // Find source prefixes by scanning through unreachable-routes
 317                         p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]);
 318                         p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]);
 319
 320                         for (ssize_t i = 0; i < len; ++i) {
 321                                 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
 322                                                 !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) {
 323                                         n[i].dprefix = p.prefix;
 324                                         break;
 325                                 }
 326                         }
 327                 }
 328         }
 329
 330         return found_default;
 331 }
 332
 333 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
 334                              uint32_t *maxival)
 335 {
 336         uint32_t minival = iface->ra_mininterval;
 337         int msecs;
 338
 339         *maxival = iface->ra_maxinterval;
 340
 341         if (*maxival > minvalid/3)
 342                 *maxival = minvalid/3;
 343
 344         if (*maxival > MaxRtrAdvInterval)
 345                 *maxival = MaxRtrAdvInterval;
 346         else if (*maxival < 4)
 347                 *maxival = 4;
 348
 349         if (minival < MinRtrAdvInterval)
 350                 minival = MinRtrAdvInterval;
 351         else if (minival > (*maxival * 3)/4)
 352                 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
 353
 354         odhcpd_urandom(&msecs, sizeof(msecs));
 355         msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
 356                         minival*1000;
 357
 358         return msecs;
 359 }
 360
 361 static uint32_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
 362 {
 363         uint32_t lifetime = 3*maxival;
 364
 365         if (iface->ra_lifetime >= 0) {
 366                 lifetime = iface->ra_lifetime;
 367                 if (lifetime > 0 && lifetime < maxival)
 368                         lifetime = maxival;
 369                 else if (lifetime > 9000)
 370                         lifetime = 9000;
 371         }
 372
 373         return lifetime;
 374 }
 375
 376 enum {
 377         IOV_RA_ADV=0,
 378         IOV_RA_PFXS,
 379         IOV_RA_ROUTES,
 380         IOV_RA_DNS,
 381         IOV_RA_SEARCH,
 382         IOV_RA_ADV_INTERVAL,
 383         IOV_RA_TOTAL,
 384 };
 385
 386 struct adv_msg {
 387         struct nd_router_advert h;
 388         struct icmpv6_opt lladdr;
 389         struct nd_opt_mtu mtu;
 390 };
 391
 392 struct nd_opt_dns_server {
 393         uint8_t type;
 394         uint8_t len;
 395         uint8_t pad;
 396         uint8_t pad2;
 397         uint32_t lifetime;
 398         struct in6_addr addr[];
 399 };
 400
 401 struct nd_opt_search_list {
 402         uint8_t type;
 403         uint8_t len;
 404         uint8_t pad;
 405         uint8_t pad2;
 406         uint32_t lifetime;
 407         uint8_t name[];
 408 };
 409
 410 struct nd_opt_route_info {
 411         uint8_t type;
 412         uint8_t len;
 413         uint8_t prefix;
 414         uint8_t flags;
 415         uint32_t lifetime;
 416         uint32_t addr[4];
 417 };
 418
 419 /* Router Advert server mode */
 420 static int send_router_advert(struct interface *iface, const struct in6_addr *from)
 421 {
 422         time_t now = odhcpd_time();
 423         struct odhcpd_ipaddr *addrs = NULL;
 424         struct adv_msg adv;
 425         struct nd_opt_prefix_info *pfxs = NULL;
 426         struct nd_opt_dns_server *dns = NULL;
 427         struct nd_opt_search_list *search = NULL;
 428         struct nd_opt_route_info *routes = NULL;
 429         struct nd_opt_adv_interval adv_interval;
 430         struct iovec iov[IOV_RA_TOTAL];
 431         struct sockaddr_in6 dest;
 432         size_t dns_sz = 0, search_sz = 0, pfxs_cnt = 0, routes_cnt = 0;
 433         ssize_t addr_cnt = 0;
 434         uint32_t minvalid = UINT32_MAX, maxival, lifetime;
 435         int msecs, mtu = iface->ra_mtu, hlim = iface->ra_hoplimit;
 436         bool default_route = false;
 437         bool valid_prefix = false;
 438         char buf[INET6_ADDRSTRLEN];
 439
 440         memset(&adv, 0, sizeof(adv));
 441         adv.h.nd_ra_type = ND_ROUTER_ADVERT;
 442
 443         if (hlim == 0)
 444                 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
 445
 446         if (hlim > 0)
 447                 adv.h.nd_ra_curhoplimit = hlim;
 448
 449         adv.h.nd_ra_flags_reserved = iface->ra_flags;
 450
 451         if (iface->route_preference < 0)
 452                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 453         else if (iface->route_preference > 0)
 454                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
 455
 456         adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
 457         adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
 458
 459         adv.lladdr.type = ND_OPT_SOURCE_LINKADDR;
 460         adv.lladdr.len = 1;
 461         odhcpd_get_mac(iface, adv.lladdr.data);
 462
 463         adv.mtu.nd_opt_mtu_type = ND_OPT_MTU;
 464         adv.mtu.nd_opt_mtu_len = 1;
 465
 466         if (mtu == 0)
 467                 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
 468
 469         if (mtu < 1280)
 470                 mtu = 1280;
 471
 472         adv.mtu.nd_opt_mtu_mtu = htonl(mtu);
 473
 474         iov[IOV_RA_ADV].iov_base = (char *)&adv;
 475         iov[IOV_RA_ADV].iov_len = sizeof(adv);
 476
 477         /* If not shutdown */
 478         if (iface->timer_rs.cb) {
 479                 size_t size = sizeof(*addrs) * iface->addr6_len;
 480
 481                 addrs = alloca(size);
 482                 memcpy(addrs, iface->addr6, size);
 483
 484                 addr_cnt = iface->addr6_len;
 485
 486                 /* Check default route */
 487                 if (iface->default_router) {
 488                         default_route = true;
 489
 490                         if (iface->default_router > 1)
 491                                 valid_prefix = true;
 492                 } else if (parse_routes(addrs, addr_cnt))
 493                         default_route = true;
 494         }
 495
 496         /* Construct Prefix Information options */
 497         for (ssize_t i = 0; i < addr_cnt; ++i) {
 498                 struct odhcpd_ipaddr *addr = &addrs[i];
 499                 struct nd_opt_prefix_info *p = NULL;
 500                 uint32_t preferred = 0;
 501                 uint32_t valid = 0;
 502
 503                 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
 504                         syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
 505                                 inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)), addr->prefix,
 506                                 addr->valid, iface->name);
 507                         continue;
 508                 }
 509
 510                 if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
 511                                    iface->pio_filter_length) != 0 ||
 512                     addr->prefix < iface->pio_filter_length) {
 513                         syslog(LOG_INFO, "Address %s filtered out as RA prefix on %s",
 514                                inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 515                                iface->name);
 516                         continue; /* PIO filtered out of this RA */
 517                 }
 518
 519                 for (size_t i = 0; i < pfxs_cnt; ++i) {
 520                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
 521                                         !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 522                                         &addr->addr.in6, addr->prefix))
 523                                 p = &pfxs[i];
 524                 }
 525
 526                 if (!p) {
 527                         struct nd_opt_prefix_info *tmp;
 528
 529                         tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
 530                         if (!tmp) {
 531                                 syslog(LOG_ERR, "Realloc failed for RA prefix option on %s", iface->name);
 532                                 continue;
 533                         }
 534
 535                         pfxs = tmp;
 536                         p = &pfxs[pfxs_cnt++];
 537                         memset(p, 0, sizeof(*p));
 538                 }
 539
 540                 if (addr->preferred > (uint32_t)now) {
 541                         preferred = TIME_LEFT(addr->preferred, now);
 542
 543                         if (iface->ra_useleasetime &&
 544                                         preferred > iface->dhcpv4_leasetime)
 545                                 preferred = iface->dhcpv4_leasetime;
 546                 }
 547
 548                 valid = TIME_LEFT(addr->valid, now);
 549                 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
 550                         valid = iface->dhcpv4_leasetime;
 551
 552                 if (minvalid > valid)
 553                         minvalid = valid;
 554
 555                 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
 556                         valid_prefix = true;
 557
 558                 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr.in6,
 559                                 (iface->ra_advrouter) ? 128 : addr->prefix);
 560                 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 561                 p->nd_opt_pi_len = 4;
 562                 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 563                 p->nd_opt_pi_flags_reserved = 0;
 564                 if (!iface->ra_not_onlink)
 565                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
 566                 if (iface->ra_slaac && addr->prefix <= 64)
 567                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 568                 if (iface->ra_advrouter)
 569                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
 570                 p->nd_opt_pi_preferred_time = htonl(preferred);
 571                 p->nd_opt_pi_valid_time = htonl(valid);
 572         }
 573
 574         iov[IOV_RA_PFXS].iov_base = (char *)pfxs;
 575         iov[IOV_RA_PFXS].iov_len = pfxs_cnt * sizeof(*pfxs);
 576
 577         /* Calculate periodic transmit */
 578         msecs = calc_adv_interval(iface, minvalid, &maxival);
 579         lifetime = calc_ra_lifetime(iface, maxival);
 580
 581         if (default_route) {
 582                 if (!valid_prefix) {
 583                         syslog(LOG_WARNING, "A default route is present but there is no public prefix "
 584                                         "on %s thus we don't announce a default route!", iface->name);
 585                         adv.h.nd_ra_router_lifetime = 0;
 586                 } else
 587                         adv.h.nd_ra_router_lifetime = htons(lifetime < UINT16_MAX ? lifetime : UINT16_MAX);
 588
 589         } else
 590                 adv.h.nd_ra_router_lifetime = 0;
 591
 592         syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->name);
 593
 594         /* DNS options */
 595         if (iface->ra_dns) {
 596                 struct in6_addr dns_pref, *dns_addr = NULL;
 597                 size_t dns_cnt = 0, search_len = iface->search_len;
 598                 uint8_t *search_domain = iface->search;
 599
 600                 /* DNS Recursive DNS */
 601                 if (iface->dns_cnt > 0) {
 602                         dns_addr = iface->dns;
 603                         dns_cnt = iface->dns_cnt;
 604                 } else if (!odhcpd_get_interface_dns_addr(iface, &dns_pref)) {
 605                         dns_addr = &dns_pref;
 606                         dns_cnt = 1;
 607                 }
 608
 609                 if (dns_cnt) {
 610                         dns_sz = sizeof(*dns) + sizeof(struct in6_addr)*dns_cnt;
 611
 612                         dns = alloca(dns_sz);
 613                         memset(dns, 0, dns_sz);
 614                         dns->type = ND_OPT_RECURSIVE_DNS;
 615                         dns->len = 1 + (2 * dns_cnt);
 616                         dns->lifetime = htonl(lifetime);
 617                         memcpy(dns->addr, dns_addr, sizeof(struct in6_addr)*dns_cnt);
 618                 }
 619
 620                 /* DNS Search options */
 621                 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 622                         uint8_t search_buf[256];
 623
 624                         int len = dn_comp(_res.dnsrch[0], search_buf,
 625                                         sizeof(search_buf), NULL, NULL);
 626                         if (len > 0) {
 627                                 search_domain = search_buf;
 628                                 search_len = len;
 629                         }
 630                 }
 631
 632                 if (search_len > 0) {
 633                         size_t search_padded = ((search_len + 7) & (~7)) + 8;
 634
 635                         search_sz = sizeof(*search) + search_padded;
 636
 637                         search = alloca(search_sz);
 638                         memset(search, 0, search_sz);
 639                         search->type = ND_OPT_DNS_SEARCH;
 640                         search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
 641                         search->lifetime = htonl(lifetime);
 642                         memcpy(search->name, search_domain, search_len);
 643                         memset(&search->name[search_len], 0, search_padded - search_len);
 644                 }
 645         }
 646
 647         iov[IOV_RA_DNS].iov_base = (char *)dns;
 648         iov[IOV_RA_DNS].iov_len = dns_sz;
 649         iov[IOV_RA_SEARCH].iov_base = (char *)search;
 650         iov[IOV_RA_SEARCH].iov_len = search_sz;
 651
 652         for (ssize_t i = 0; i < addr_cnt; ++i) {
 653                 struct odhcpd_ipaddr *addr = &addrs[i];
 654                 struct nd_opt_route_info *tmp;
 655                 uint32_t valid;
 656
 657                 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now) {
 658                         syslog(LOG_INFO, "Address %s (dprefix %d, valid %u) not suitable as RA route on %s",
 659                                 inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 660                                 addr->dprefix, addr->valid, iface->name);
 661
 662                         continue; /* Address not suitable */
 663                 }
 664
 665                 if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
 666                                 iface->pio_filter_length) != 0 ||
 667                                 addr->prefix < iface->pio_filter_length) {
 668                         syslog(LOG_INFO, "Address %s filtered out as RA route on %s",
 669                                inet_ntop(AF_INET6, &addr->addr.in6, buf, sizeof(buf)),
 670                                iface->name);
 671                         continue; /* PIO filtered out of this RA */
 672                 }
 673
 674                 if (addr->dprefix > 32) {
 675                         addr->addr.in6.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
 676                 } else if (addr->dprefix <= 32) {
 677                         addr->addr.in6.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
 678                         addr->addr.in6.s6_addr32[1] = 0;
 679                 }
 680
 681                 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
 682                 if (!tmp) {
 683                         syslog(LOG_ERR, "Realloc failed for RA route option on %s", iface->name);
 684                         continue;
 685                 }
 686
 687                 routes = tmp;
 688
 689                 memset(&routes[routes_cnt], 0, sizeof(*routes));
 690                 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 691                 routes[routes_cnt].len = sizeof(*routes) / 8;
 692                 routes[routes_cnt].prefix = addr->dprefix;
 693                 routes[routes_cnt].flags = 0;
 694                 if (iface->route_preference < 0)
 695                         routes[routes_cnt].flags |= ND_RA_PREF_LOW;
 696                 else if (iface->route_preference > 0)
 697                         routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
 698
 699                 valid = TIME_LEFT(addr->valid, now);
 700                 routes[routes_cnt].lifetime = htonl(valid < lifetime ? valid : lifetime);
 701                 routes[routes_cnt].addr[0] = addr->addr.in6.s6_addr32[0];
 702                 routes[routes_cnt].addr[1] = addr->addr.in6.s6_addr32[1];
 703                 routes[routes_cnt].addr[2] = 0;
 704                 routes[routes_cnt].addr[3] = 0;
 705
 706                 ++routes_cnt;
 707         }
 708
 709         iov[IOV_RA_ROUTES].iov_base = (char *)routes;
 710         iov[IOV_RA_ROUTES].iov_len = routes_cnt * sizeof(*routes);
 711
 712         memset(&adv_interval, 0, sizeof(adv_interval));
 713         adv_interval.nd_opt_adv_interval_type = ND_OPT_RTR_ADV_INTERVAL;
 714         adv_interval.nd_opt_adv_interval_len = 1;
 715         adv_interval.nd_opt_adv_interval_ival = htonl(maxival);
 716
 717         iov[IOV_RA_ADV_INTERVAL].iov_base = (char *)&adv_interval;
 718         iov[IOV_RA_ADV_INTERVAL].iov_len = adv_interval.nd_opt_adv_interval_len * 8;
 719
 720         memset(&dest, 0, sizeof(dest));
 721         dest.sin6_family = AF_INET6;
 722
 723         if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
 724                 dest.sin6_addr = *from;
 725         else
 726                 inet_pton(AF_INET6, ALL_IPV6_NODES, &dest.sin6_addr);
 727
 728         syslog(LOG_NOTICE, "Sending a RA on %s", iface->name);
 729
 730         odhcpd_send(iface->router_event.uloop.fd, &dest, iov, ARRAY_SIZE(iov), iface);
 731
 732         free(pfxs);
 733         free(routes);
 734
 735         return msecs;
 736 }
 737
 738
 739 static void trigger_router_advert(struct uloop_timeout *event)
 740 {
 741         struct interface *iface = container_of(event, struct interface, timer_rs);
 742         int msecs = send_router_advert(iface, NULL);
 743
 744         /* Rearm timer if not shut down */
 745         if (event->cb)
 746                 uloop_timeout_set(event, msecs);
 747 }
 748
 749
 750 /* Event handler for incoming ICMPv6 packets */
 751 static void handle_icmpv6(void *addr, void *data, size_t len,
 752                 struct interface *iface, _unused void *dest)
 753 {
 754         struct icmp6_hdr *hdr = data;
 755         struct sockaddr_in6 *from = addr;
 756
 757         if (!router_icmpv6_valid(addr, data, len))
 758                 return;
 759
 760         if ((iface->ra == MODE_SERVER && !iface->master)) { /* Server mode */
 761                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
 762                         send_router_advert(iface, &from->sin6_addr);
 763         } else if (iface->ra == MODE_RELAY) { /* Relay mode */
 764                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master) {
 765                         struct interface *c;
 766
 767                         avl_for_each_element(&interfaces, c, avl) {
 768                                 if (!c->master || c->ra != MODE_RELAY)
 769                                         continue;
 770
 771                                 forward_router_solicitation(c);
 772                         }
 773                 } else if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
 774                         forward_router_advertisement(iface, data, len);
 775         }
 776 }
 777
 778
 779 /* Forward router solicitation */
 780 static void forward_router_solicitation(const struct interface *iface)
 781 {
 782         struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
 783         struct iovec iov = {&rs, sizeof(rs)};
 784         struct sockaddr_in6 all_routers;
 785
 786         if (!iface)
 787                 return;
 788
 789         memset(&all_routers, 0, sizeof(all_routers));
 790         all_routers.sin6_family = AF_INET6;
 791         inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &all_routers.sin6_addr);
 792         all_routers.sin6_scope_id = iface->ifindex;
 793
 794         syslog(LOG_NOTICE, "Sending RS to %s", iface->name);
 795         odhcpd_send(iface->router_event.uloop.fd, &all_routers, &iov, 1, iface);
 796 }
 797
 798
 799 /* Handler for incoming router solicitations on slave interfaces */
 800 static void forward_router_advertisement(const struct interface *iface, uint8_t *data, size_t len)
 801 {
 802         struct nd_router_advert *adv = (struct nd_router_advert *)data;
 803         struct sockaddr_in6 all_nodes;
 804         struct icmpv6_opt *opt;
 805         struct interface *c;
 806         struct iovec iov = { .iov_base = data, .iov_len = len };
 807         /* Rewrite options */
 808         uint8_t *end = data + len;
 809         uint8_t *mac_ptr = NULL;
 810         struct in6_addr *dns_ptr = NULL;
 811         size_t dns_count = 0;
 812
 813         icmpv6_for_each_option(opt, &adv[1], end) {
 814                 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 815                         /* Store address of source MAC-address */
 816                         mac_ptr = opt->data;
 817                 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
 818                         /* Check if we have to rewrite DNS */
 819                         dns_ptr = (struct in6_addr*)&opt->data[6];
 820                         dns_count = (opt->len - 1) / 2;
 821                 }
 822         }
 823
 824         syslog(LOG_NOTICE, "Got a RA on %s", iface->name);
 825
 826         /* Indicate a proxy, however we don't follow the rest of RFC 4389 yet */
 827         adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
 828
 829         /* Forward advertisement to all slave interfaces */
 830         memset(&all_nodes, 0, sizeof(all_nodes));
 831         all_nodes.sin6_family = AF_INET6;
 832         inet_pton(AF_INET6, ALL_IPV6_NODES, &all_nodes.sin6_addr);
 833
 834         avl_for_each_element(&interfaces, c, avl) {
 835                 if (c->ra != MODE_RELAY || c->master)
 836                         continue;
 837
 838                 /* Fixup source hardware address option */
 839                 if (mac_ptr)
 840                         odhcpd_get_mac(c, mac_ptr);
 841
 842                 /* If we have to rewrite DNS entries */
 843                 if (c->always_rewrite_dns && dns_ptr && dns_count > 0) {
 844                         const struct in6_addr *rewrite = c->dns;
 845                         struct in6_addr addr;
 846                         size_t rewrite_cnt = c->dns_cnt;
 847
 848                         if (rewrite_cnt == 0) {
 849                                 if (odhcpd_get_interface_dns_addr(c, &addr))
 850                                         continue; /* Unable to comply */
 851
 852                                 rewrite = &addr;
 853                                 rewrite_cnt = 1;
 854                         }
 855
 856                         /* Copy over any other addresses */
 857                         for (size_t i = 0; i < dns_count; ++i) {
 858                                 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
 859                                 dns_ptr[i] = rewrite[j];
 860                         }
 861                 }
 862
 863                 syslog(LOG_NOTICE, "Forward a RA on %s", c->name);
 864
 865                 odhcpd_send(c->router_event.uloop.fd, &all_nodes, &iov, 1, c);
 866         }
 867 }