src/router.c

   1 /**
   2  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <errno.h>
  16 #include <fcntl.h>
  17 #include <signal.h>
  18 #include <resolv.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <stdbool.h>
  23 #include <arpa/inet.h>
  24 #include <net/route.h>
  25
  26 #include "router.h"
  27 #include "odhcpd.h"
  28
  29
  30 static void forward_router_solicitation(const struct interface *iface);
  31 static void forward_router_advertisement(uint8_t *data, size_t len);
  32
  33 static void handle_icmpv6(void *addr, void *data, size_t len,
  34                 struct interface *iface, void *dest);
  35 static void trigger_router_advert(struct uloop_timeout *event);
  36 static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info);
  37
  38 static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
  39 static struct netevent_handler router_netevent_handler = { .cb = router_netevent_cb, };
  40
  41 static FILE *fp_route = NULL;
  42
  43
  44 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
  45
  46 int router_init(void)
  47 {
  48         struct icmp6_filter filt;
  49         int ret = 0;
  50
  51         /* Open ICMPv6 socket */
  52         router_event.uloop.fd = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
  53         if (router_event.uloop.fd < 0) {
  54                 syslog(LOG_ERR, "socket(AF_INET6): %m");
  55                 ret = -1;
  56                 goto out;
  57         }
  58
  59         /* Let the kernel compute our checksums */
  60         int val = 2;
  61         if (setsockopt(router_event.uloop.fd, IPPROTO_RAW, IPV6_CHECKSUM,
  62                                 &val, sizeof(val)) < 0) {
  63                 syslog(LOG_ERR, "setsockopt(IPV6_CHECKSUM): %m");
  64                 ret = -1;
  65                 goto out;
  66         }
  67
  68         /* This is required by RFC 4861 */
  69         val = 255;
  70         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
  71                                 &val, sizeof(val)) < 0) {
  72                 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m");
  73                 ret = -1;
  74                 goto out;
  75         }
  76
  77         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS,
  78                                 &val, sizeof(val)) < 0) {
  79                 syslog(LOG_ERR, "setsockopt(IPV6_UNICAST_HOPS): %m");
  80                 ret = -1;
  81                 goto out;
  82         }
  83
  84         /* We need to know the source interface */
  85         val = 1;
  86         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
  87                                 &val, sizeof(val)) < 0) {
  88                 syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m");
  89                 ret = -1;
  90                 goto out;
  91         }
  92
  93         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
  94                                 &val, sizeof(val)) < 0) {
  95                 syslog(LOG_ERR, "setsockopt(IPV6_RECVHOPLIMIT): %m");
  96                 ret = -1;
  97                 goto out;
  98         }
  99
 100         /* Don't loop back */
 101         val = 0;
 102         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
 103                                 &val, sizeof(val)) < 0) {
 104                 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m");
 105                 ret = -1;
 106                 goto out;
 107         }
 108
 109         /* Filter ICMPv6 package types */
 110         ICMP6_FILTER_SETBLOCKALL(&filt);
 111         ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
 112         ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
 113         if (setsockopt(router_event.uloop.fd, IPPROTO_ICMPV6, ICMP6_FILTER,
 114                                 &filt, sizeof(filt)) < 0) {
 115                 syslog(LOG_ERR, "setsockopt(ICMP6_FILTER): %m");
 116                 ret = -1;
 117                 goto out;
 118         }
 119
 120         if (!(fp_route = fopen("/proc/net/ipv6_route", "r"))) {
 121                 syslog(LOG_ERR, "fopen(/proc/net/ipv6_route): %m");
 122                 ret = -1;
 123                 goto out;
 124         }
 125
 126         if (netlink_add_netevent_handler(&router_netevent_handler) < 0) {
 127                 syslog(LOG_ERR, "Failed to add netevent handler");
 128                 ret = -1;
 129                 goto out;
 130         }
 131
 132         /* Register socket */
 133         odhcpd_register(&router_event);
 134 out:
 135         if (ret < 0) {
 136                 if (router_event.uloop.fd > 0) {
 137                         close(router_event.uloop.fd);
 138                         router_event.uloop.fd = -1;
 139                 }
 140
 141                 if (fp_route) {
 142                         fclose(fp_route);
 143                         fp_route = NULL;
 144                 }
 145         }
 146
 147         return ret;
 148 }
 149
 150
 151 int router_setup_interface(struct interface *iface, bool enable)
 152 {
 153         struct ipv6_mreq mreq;
 154         int ret = 0;
 155
 156         if (!fp_route || router_event.uloop.fd < 0) {
 157                 ret = -1;
 158                 goto out;
 159         }
 160
 161         uloop_timeout_cancel(&iface->timer_rs);
 162         iface->timer_rs.cb = NULL;
 163
 164         memset(&mreq, 0, sizeof(mreq));
 165         mreq.ipv6mr_interface = iface->ifindex;
 166         inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr);
 167         setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 168                         &mreq, sizeof(mreq));
 169
 170         inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &mreq.ipv6mr_multiaddr);
 171         setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 172                         &mreq, sizeof(mreq));
 173
 174         if (!enable) {
 175                 if (iface->ra)
 176                         trigger_router_advert(&iface->timer_rs);
 177         } else {
 178                 if (iface->ra == MODE_RELAY && iface->master) {
 179                         inet_pton(AF_INET6, ALL_IPV6_NODES, &mreq.ipv6mr_multiaddr);
 180                         forward_router_solicitation(iface);
 181                 } else if (iface->ra == MODE_SERVER && !iface->master) {
 182                         iface->timer_rs.cb = trigger_router_advert;
 183                         uloop_timeout_set(&iface->timer_rs, 1000);
 184                 }
 185
 186                 if (iface->ra == MODE_RELAY || (iface->ra == MODE_SERVER && !iface->master)) {
 187                         if (setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
 188                                         IPV6_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
 189                                 ret = -1;
 190                                 syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
 191                         }
 192                 }
 193         }
 194 out:
 195         return ret;
 196 }
 197
 198
 199 static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info)
 200 {
 201         struct interface *iface;
 202
 203         switch (event) {
 204         case NETEV_ROUTE6_ADD:
 205         case NETEV_ROUTE6_DEL:
 206                 if (info->rt.dst_len)
 207                         break;
 208
 209                 list_for_each_entry(iface, &interfaces, head) {
 210                         if (iface->ra == MODE_SERVER && !iface->master)
 211                                 uloop_timeout_set(&iface->timer_rs, 1000);
 212                 }
 213                 break;
 214         case NETEV_ADDR6LIST_CHANGE:
 215                 iface = info->iface;
 216                 if (iface && iface->ra == MODE_SERVER && !iface->master)
 217                         uloop_timeout_set(&iface->timer_rs, 1000);
 218                 break;
 219         default:
 220                 break;
 221         }
 222 }
 223
 224
 225 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
 226 {
 227         struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
 228         struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
 229
 230         /* Hoplimit is already checked in odhcpd_receive_packets */
 231         if (len < sizeof(*hdr) || hdr->icmp6_code)
 232                 return false;
 233
 234         switch (hdr->icmp6_type) {
 235         case ND_ROUTER_ADVERT:
 236                 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
 237                         return false;
 238
 239                 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
 240                 break;
 241
 242         case ND_ROUTER_SOLICIT:
 243                 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
 244                 break;
 245
 246         default:
 247                 return false;
 248         }
 249
 250         icmpv6_for_each_option(opt, opt, end)
 251                 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
 252                                 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
 253                                 hdr->icmp6_type == ND_ROUTER_SOLICIT)
 254                         return false;
 255
 256         /* Check all options parsed successfully */
 257         return opt == end;
 258 }
 259
 260
 261 /* Detect whether a default route exists, also find the source prefixes */
 262 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 263 {
 264         rewind(fp_route);
 265
 266         char line[512], ifname[16];
 267         bool found_default = false;
 268         struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0,
 269                                         .dprefix = 0, .preferred = 0, .valid = 0};
 270
 271         while (fgets(line, sizeof(line), fp_route)) {
 272                 uint32_t rflags;
 273                 if (sscanf(line, "00000000000000000000000000000000 00 "
 274                                 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
 275                                 strcmp(ifname, "lo")) {
 276                         found_default = true;
 277                 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
 278                                 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
 279                                 &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) &&
 280                                 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
 281                         // Find source prefixes by scanning through unreachable-routes
 282                         p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]);
 283                         p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]);
 284
 285                         for (ssize_t i = 0; i < len; ++i) {
 286                                 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
 287                                                 !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) {
 288                                         n[i].dprefix = p.prefix;
 289                                         break;
 290                                 }
 291                         }
 292
 293                 }
 294         }
 295
 296         return found_default;
 297 }
 298
 299 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
 300                 uint32_t *maxival)
 301 {
 302         uint32_t minival = iface->ra_mininterval;
 303         int msecs;
 304
 305         *maxival = iface->ra_maxinterval;
 306
 307         if (*maxival > minvalid/3)
 308                 *maxival = minvalid/3;
 309
 310         if (*maxival > MaxRtrAdvInterval)
 311                 *maxival = MaxRtrAdvInterval;
 312         else if (*maxival < 4)
 313                 *maxival = 4;
 314
 315         if (minival < MinRtrAdvInterval)
 316                 minival = MinRtrAdvInterval;
 317         else if (minival > (*maxival * 3)/4)
 318                 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
 319
 320         odhcpd_urandom(&msecs, sizeof(msecs));
 321         msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
 322                         minival*1000;
 323
 324         return msecs;
 325 }
 326
 327 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
 328 {
 329         uint16_t lifetime = 3*maxival;
 330
 331         if (iface->ra_lifetime >= 0) {
 332                 lifetime = iface->ra_lifetime;
 333                 if (lifetime < maxival)
 334                         lifetime = maxival;
 335                 else if (lifetime > 9000)
 336                         lifetime = 9000;
 337         }
 338
 339         return lifetime;
 340 }
 341
 342 enum {
 343         IOV_RA_ADV=0,
 344         IOV_RA_PFXS,
 345         IOV_RA_ROUTES,
 346         IOV_RA_DNS,
 347         IOV_RA_DNS_ADDR,
 348         IOV_RA_SEARCH,
 349         IOV_RA_ADV_INTERVAL,
 350         IOV_RA_TOTAL,
 351 };
 352
 353 /* Router Advert server mode */
 354 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
 355 {
 356         time_t now = odhcpd_time();
 357         int mtu = iface->ra_mtu;
 358         int hlim = iface->ra_hoplimit;
 359
 360         if (mtu == 0)
 361                 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
 362
 363         if (mtu < 1280)
 364                 mtu = 1280;
 365
 366         if (hlim == 0)
 367                 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
 368
 369         struct {
 370                 struct nd_router_advert h;
 371                 struct icmpv6_opt lladdr;
 372                 struct nd_opt_mtu mtu;
 373         } adv = {
 374                 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
 375                 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
 376                 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
 377         };
 378
 379         if (hlim > 0)
 380                 adv.h.nd_ra_curhoplimit = hlim;
 381
 382         if (iface->dhcpv6) {
 383                 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
 384
 385                 if (iface->ra_managed >= RA_MANAGED_MFLAG)
 386                         adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
 387         }
 388
 389         if (iface->route_preference < 0)
 390                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 391         else if (iface->route_preference > 0)
 392                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
 393
 394         adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
 395         adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
 396
 397         odhcpd_get_mac(iface, adv.lladdr.data);
 398
 399         /* If not currently shutting down */
 400         struct odhcpd_ipaddr *addrs = NULL;
 401         ssize_t ipcnt = 0;
 402         uint32_t minvalid = UINT32_MAX;
 403         bool default_route = false;
 404         bool valid_prefix = false;
 405
 406         /* If not shutdown */
 407         if (iface->timer_rs.cb) {
 408                 size_t size = sizeof(*addrs) * iface->addr6_len;
 409                 addrs = alloca(size);
 410                 memcpy(addrs, iface->addr6, size);
 411
 412                 ipcnt = iface->addr6_len;
 413
 414                 /* Check default route */
 415                 if (iface->default_router) {
 416                         default_route = true;
 417
 418                         if (iface->default_router > 1)
 419                                 valid_prefix = true;
 420                 } else if (parse_routes(addrs, ipcnt))
 421                         default_route = true;
 422         }
 423
 424
 425         struct in6_addr dns_pref, *dns_addr = &dns_pref;
 426         size_t dns_cnt = 1;
 427
 428         odhcpd_get_interface_dns_addr(iface, &dns_pref);
 429
 430         /* Construct Prefix Information options */
 431         size_t pfxs_cnt = 0;
 432         struct nd_opt_prefix_info *pfxs = NULL;
 433
 434         for (ssize_t i = 0; i < ipcnt; ++i) {
 435                 struct odhcpd_ipaddr *addr = &addrs[i];
 436                 uint32_t preferred = 0;
 437                 uint32_t valid = 0;
 438
 439                 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
 440                         char namebuf[INET6_ADDRSTRLEN];
 441
 442                         inet_ntop(AF_INET6, &addr->addr.in6, namebuf, sizeof(namebuf));
 443                         syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
 444                                         namebuf, addr->prefix, addr->valid, iface->ifname);
 445                         continue;
 446                 }
 447
 448                 if (odhcpd_bmemcmp(&addr->addr, &iface->pio_filter_addr,
 449                                 iface->pio_filter_length) != 0 ||
 450                                 addr->prefix < iface->pio_filter_length)
 451                         continue; // PIO filtered out of this RA
 452
 453                 struct nd_opt_prefix_info *p = NULL;
 454                 for (size_t i = 0; i < pfxs_cnt; ++i) {
 455                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
 456                                         !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 457                                         &addr->addr.in6, addr->prefix))
 458                                 p = &pfxs[i];
 459                 }
 460
 461                 if (!p) {
 462                         struct nd_opt_prefix_info *tmp;
 463
 464                         tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
 465                         if (!tmp) {
 466                                 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
 467                                 continue;
 468                         }
 469
 470                         pfxs = tmp;
 471                         p = &pfxs[pfxs_cnt++];
 472                         memset(p, 0, sizeof(*p));
 473                 }
 474
 475                 if (addr->preferred > (uint32_t)now) {
 476                         preferred = TIME_LEFT(addr->preferred, now);
 477
 478                         if (iface->ra_useleasetime &&
 479                                         preferred > iface->dhcpv4_leasetime)
 480                                 preferred = iface->dhcpv4_leasetime;
 481                 }
 482
 483                 valid = TIME_LEFT(addr->valid, now);
 484                 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
 485                         valid = iface->dhcpv4_leasetime;
 486
 487                 if (minvalid > valid)
 488                         minvalid = valid;
 489
 490                 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
 491                         valid_prefix = true;
 492
 493                 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr.in6,
 494                                 (iface->ra_advrouter) ? 128 : addr->prefix);
 495                 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 496                 p->nd_opt_pi_len = 4;
 497                 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 498                 p->nd_opt_pi_flags_reserved = 0;
 499                 if (!iface->ra_not_onlink)
 500                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
 501                 if (iface->ra_managed < RA_MANAGED_NO_AFLAG && addr->prefix <= 64)
 502                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 503                 if (iface->ra_advrouter)
 504                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
 505                 p->nd_opt_pi_preferred_time = htonl(preferred);
 506                 p->nd_opt_pi_valid_time = htonl(valid);
 507         }
 508
 509         /* Calculate periodic transmit */
 510         uint32_t maxival;
 511         int msecs = calc_adv_interval(iface, minvalid, &maxival);
 512
 513         if (default_route) {
 514                 if (!valid_prefix) {
 515                         syslog(LOG_WARNING, "A default route is present but there is no public prefix "
 516                                         "on %s thus we don't announce a default route!", iface->ifname);
 517                         adv.h.nd_ra_router_lifetime = 0;
 518                 } else
 519                         adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
 520
 521         } else
 522                 adv.h.nd_ra_router_lifetime = 0;
 523
 524         syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
 525
 526         /* DNS Recursive DNS */
 527         if (iface->dns_cnt > 0) {
 528                 dns_addr = iface->dns;
 529                 dns_cnt = iface->dns_cnt;
 530         }
 531
 532         if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
 533                 dns_cnt = 0;
 534
 535         struct {
 536                 uint8_t type;
 537                 uint8_t len;
 538                 uint8_t pad;
 539                 uint8_t pad2;
 540                 uint32_t lifetime;
 541         } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
 542
 543         /* DNS Search options */
 544         uint8_t search_buf[256], *search_domain = iface->search;
 545         size_t search_len = iface->search_len, search_padded = 0;
 546
 547         if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 548                 int len = dn_comp(_res.dnsrch[0], search_buf,
 549                                 sizeof(search_buf), NULL, NULL);
 550                 if (len > 0) {
 551                         search_domain = search_buf;
 552                         search_len = len;
 553                 }
 554         }
 555
 556         if (search_len > 0)
 557                 search_padded = ((search_len + 7) & (~7)) + 8;
 558
 559         struct {
 560                 uint8_t type;
 561                 uint8_t len;
 562                 uint8_t pad;
 563                 uint8_t pad2;
 564                 uint32_t lifetime;
 565                 uint8_t name[];
 566         } *search = alloca(sizeof(*search) + search_padded);
 567
 568         search->type = ND_OPT_DNS_SEARCH;
 569         search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
 570         search->pad = 0;
 571         search->pad2 = 0;
 572
 573         if (search_len > 0) {
 574                 memcpy(search->name, search_domain, search_len);
 575                 memset(&search->name[search_len], 0, search_padded - search_len);
 576         }
 577
 578         size_t routes_cnt = 0;
 579         struct {
 580                 uint8_t type;
 581                 uint8_t len;
 582                 uint8_t prefix;
 583                 uint8_t flags;
 584                 uint32_t lifetime;
 585                 uint32_t addr[4];
 586         } *tmp, *routes = NULL;
 587
 588         for (ssize_t i = 0; i < ipcnt; ++i) {
 589                 struct odhcpd_ipaddr *addr = &addrs[i];
 590                 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now)
 591                         continue; // Address not suitable
 592
 593                 if (addr->dprefix > 32) {
 594                         addr->addr.in6.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
 595                 } else if (addr->dprefix <= 32) {
 596                         addr->addr.in6.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
 597                         addr->addr.in6.s6_addr32[1] = 0;
 598                 }
 599
 600                 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
 601                 if (!tmp) {
 602                         syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
 603                         continue;
 604                 }
 605
 606                 routes = tmp;
 607
 608                 memset(&routes[routes_cnt], 0, sizeof(*routes));
 609                 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 610                 routes[routes_cnt].len = sizeof(*routes) / 8;
 611                 routes[routes_cnt].prefix = addr->dprefix;
 612                 routes[routes_cnt].flags = 0;
 613                 if (iface->route_preference < 0)
 614                         routes[routes_cnt].flags |= ND_RA_PREF_LOW;
 615                 else if (iface->route_preference > 0)
 616                         routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
 617                 routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now));
 618                 routes[routes_cnt].addr[0] = addr->addr.in6.s6_addr32[0];
 619                 routes[routes_cnt].addr[1] = addr->addr.in6.s6_addr32[1];
 620                 routes[routes_cnt].addr[2] = 0;
 621                 routes[routes_cnt].addr[3] = 0;
 622
 623                 ++routes_cnt;
 624         }
 625
 626         search->lifetime = htonl(maxival*10);
 627         dns.lifetime = search->lifetime;
 628
 629         struct icmpv6_opt adv_interval = {
 630                 .type = ND_OPT_RTR_ADV_INTERVAL,
 631                 .len = 1,
 632                 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
 633         };
 634
 635         struct iovec iov[IOV_RA_TOTAL] = {
 636                         [IOV_RA_ADV] = {&adv, sizeof(adv)},
 637                         [IOV_RA_PFXS] = {pfxs, pfxs_cnt * sizeof(*pfxs)},
 638                         [IOV_RA_ROUTES] = {routes, routes_cnt * sizeof(*routes)},
 639                         [IOV_RA_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
 640                         [IOV_RA_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)},
 641                         [IOV_RA_SEARCH] = {search, search->len * 8},
 642                         [IOV_RA_ADV_INTERVAL] = {&adv_interval, adv_interval.len * 8}};
 643         struct sockaddr_in6 dest;
 644
 645         memset(&dest, 0, sizeof(dest));
 646         dest.sin6_family = AF_INET6;
 647
 648         if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
 649                 dest.sin6_addr = *from;
 650         else
 651                 inet_pton(AF_INET6, ALL_IPV6_NODES, &dest.sin6_addr);
 652
 653         odhcpd_send(router_event.uloop.fd,
 654                         &dest, iov, ARRAY_SIZE(iov), iface);
 655
 656         free(pfxs);
 657         free(routes);
 658
 659         return msecs;
 660 }
 661
 662
 663 static void trigger_router_advert(struct uloop_timeout *event)
 664 {
 665         struct interface *iface = container_of(event, struct interface, timer_rs);
 666         int msecs = send_router_advert(iface, NULL);
 667
 668         /* Rearm timer if not shut down */
 669         if (event->cb)
 670                 uloop_timeout_set(event, msecs);
 671 }
 672
 673
 674 /* Event handler for incoming ICMPv6 packets */
 675 static void handle_icmpv6(void *addr, void *data, size_t len,
 676                 struct interface *iface, _unused void *dest)
 677 {
 678         struct icmp6_hdr *hdr = data;
 679         struct sockaddr_in6 *from = addr;
 680
 681         if (!router_icmpv6_valid(addr, data, len))
 682                 return;
 683
 684         if ((iface->ra == MODE_SERVER && !iface->master)) { /* Server mode */
 685                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
 686                         send_router_advert(iface, &from->sin6_addr);
 687         } else if (iface->ra == MODE_RELAY) { /* Relay mode */
 688                 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
 689                         forward_router_advertisement(data, len);
 690                 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
 691                         forward_router_solicitation(odhcpd_get_master_interface());
 692         }
 693 }
 694
 695
 696 /* Forward router solicitation */
 697 static void forward_router_solicitation(const struct interface *iface)
 698 {
 699         struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
 700         struct iovec iov = {&rs, sizeof(rs)};
 701         struct sockaddr_in6 all_routers;
 702
 703         if (!iface)
 704                 return;
 705
 706         memset(&all_routers, 0, sizeof(all_routers));
 707         all_routers.sin6_family = AF_INET6;
 708         inet_pton(AF_INET6, ALL_IPV6_ROUTERS, &all_routers.sin6_addr);
 709         all_routers.sin6_scope_id = iface->ifindex;
 710
 711         syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
 712         odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
 713 }
 714
 715
 716 /* Handler for incoming router solicitations on slave interfaces */
 717 static void forward_router_advertisement(uint8_t *data, size_t len)
 718 {
 719         struct nd_router_advert *adv = (struct nd_router_advert *)data;
 720         struct sockaddr_in6 all_nodes;
 721
 722         /* Rewrite options */
 723         uint8_t *end = data + len;
 724         uint8_t *mac_ptr = NULL;
 725         struct in6_addr *dns_ptr = NULL;
 726         size_t dns_count = 0;
 727
 728         struct icmpv6_opt *opt;
 729         icmpv6_for_each_option(opt, &adv[1], end) {
 730                 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 731                         /* Store address of source MAC-address */
 732                         mac_ptr = opt->data;
 733                 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
 734                         /* Check if we have to rewrite DNS */
 735                         dns_ptr = (struct in6_addr*)&opt->data[6];
 736                         dns_count = (opt->len - 1) / 2;
 737                 }
 738         }
 739
 740         syslog(LOG_NOTICE, "Got a RA");
 741
 742         /* Indicate a proxy, however we don't follow the rest of RFC 4389 yet */
 743         adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
 744
 745         /* Forward advertisement to all slave interfaces */
 746         memset(&all_nodes, 0, sizeof(all_nodes));
 747         all_nodes.sin6_family = AF_INET6;
 748         inet_pton(AF_INET6, ALL_IPV6_NODES, &all_nodes.sin6_addr);
 749
 750         struct iovec iov = {data, len};
 751
 752         struct interface *iface;
 753         list_for_each_entry(iface, &interfaces, head) {
 754                 if (iface->ra != MODE_RELAY || iface->master)
 755                         continue;
 756
 757                 /* Fixup source hardware address option */
 758                 if (mac_ptr)
 759                         odhcpd_get_mac(iface, mac_ptr);
 760
 761                 /* If we have to rewrite DNS entries */
 762                 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
 763                         const struct in6_addr *rewrite = iface->dns;
 764                         struct in6_addr addr;
 765                         size_t rewrite_cnt = iface->dns_cnt;
 766
 767                         if (rewrite_cnt == 0) {
 768                                 if (odhcpd_get_interface_dns_addr(iface, &addr))
 769                                         continue; /* Unable to comply */
 770
 771                                 rewrite = &addr;
 772                                 rewrite_cnt = 1;
 773                         }
 774
 775                         /* Copy over any other addresses */
 776                         for (size_t i = 0; i < dns_count; ++i) {
 777                                 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
 778                                 dns_ptr[i] = rewrite[j];
 779                         }
 780                 }
 781
 782                 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);
 783         }
 784 }