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 sigusr1_refresh(int signal);
  37
  38 static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
  39
  40 static FILE *fp_route = NULL;
  41
  42 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
  43
  44 int init_router(void)
  45 {
  46         // Open ICMPv6 socket
  47         int sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
  48         if (sock < 0 && errno != EAFNOSUPPORT) {
  49                 syslog(LOG_ERR, "Failed to open RAW-socket: %s", strerror(errno));
  50                 return -1;
  51         }
  52
  53         // Let the kernel compute our checksums
  54         int val = 2;
  55         setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
  56
  57         // This is required by RFC 4861
  58         val = 255;
  59         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
  60         setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
  61
  62         // We need to know the source interface
  63         val = 1;
  64         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
  65         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
  66
  67         // Don't loop back
  68         val = 0;
  69         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
  70
  71         // Filter ICMPv6 package types
  72         struct icmp6_filter filt;
  73         ICMP6_FILTER_SETBLOCKALL(&filt);
  74         ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
  75         ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
  76         setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
  77
  78         // Register socket
  79         router_event.uloop.fd = sock;
  80         odhcpd_register(&router_event);
  81
  82         if (!(fp_route = fopen("/proc/net/ipv6_route", "r")))
  83                 syslog(LOG_ERR, "Failed to open routing table: %s",
  84                                 strerror(errno));
  85
  86         signal(SIGUSR1, sigusr1_refresh);
  87         return 0;
  88 }
  89
  90
  91 int setup_router_interface(struct interface *iface, bool enable)
  92 {
  93         if (!fp_route || router_event.uloop.fd < 0)
  94                 return -1;
  95
  96         struct ipv6_mreq all_nodes = {ALL_IPV6_NODES, iface->ifindex};
  97         struct ipv6_mreq all_routers = {ALL_IPV6_ROUTERS, iface->ifindex};
  98
  99         uloop_timeout_cancel(&iface->timer_rs);
 100         iface->timer_rs.cb = NULL;
 101
 102         if (iface->ifindex <= 0)
 103                 return -1;
 104
 105         setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 106                         &all_nodes, sizeof(all_nodes));
 107         setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
 108                         &all_routers, sizeof(all_routers));
 109
 110         if (!enable) {
 111                 if (iface->ra)
 112                         trigger_router_advert(&iface->timer_rs);
 113         } else {
 114                 void *mreq = &all_routers;
 115
 116                 if (iface->ra == RELAYD_RELAY && iface->master) {
 117                         mreq = &all_nodes;
 118                         forward_router_solicitation(iface);
 119                 } else if (iface->ra == RELAYD_SERVER && !iface->master) {
 120                         iface->timer_rs.cb = trigger_router_advert;
 121                         uloop_timeout_set(&iface->timer_rs, 1000);
 122                         ndp_rqs_addr6_dump();
 123                 }
 124
 125                 if (iface->ra == RELAYD_RELAY || (iface->ra == RELAYD_SERVER && !iface->master))
 126                         setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
 127                                         IPV6_ADD_MEMBERSHIP, mreq, sizeof(all_nodes));
 128         }
 129         return 0;
 130 }
 131
 132
 133 // Signal handler to resend all RDs
 134 static void sigusr1_refresh(_unused int signal)
 135 {
 136         struct interface *iface;
 137         list_for_each_entry(iface, &interfaces, head)
 138                 if (iface->ra == RELAYD_SERVER && !iface->master)
 139                         uloop_timeout_set(&iface->timer_rs, 1000);
 140 }
 141
 142 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
 143 {
 144         struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
 145         struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
 146
 147         /* Hoplimit is already checked in odhcpd_receive_packets */
 148         if (len < sizeof(*hdr) || hdr->icmp6_code)
 149                 return false;
 150
 151         switch (hdr->icmp6_type) {
 152         case ND_ROUTER_ADVERT:
 153                 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
 154                         return false;
 155
 156                 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
 157                 break;
 158
 159         case ND_ROUTER_SOLICIT:
 160                 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
 161                 break;
 162
 163         default:
 164                 return false;
 165         }
 166
 167         icmpv6_for_each_option(opt, opt, end)
 168                 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
 169                                 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
 170                                 hdr->icmp6_type == ND_ROUTER_SOLICIT)
 171                         return false;
 172
 173         // Check all options parsed successfully
 174         return opt == end;
 175 }
 176
 177
 178 // Detect whether a default route exists, also find the source prefixes
 179 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 180 {
 181         rewind(fp_route);
 182
 183         char line[512], ifname[16];
 184         bool found_default = false;
 185         struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, 0, 0, 0};
 186         while (fgets(line, sizeof(line), fp_route)) {
 187                 uint32_t rflags;
 188                 if (sscanf(line, "00000000000000000000000000000000 00 "
 189                                 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
 190                                 strcmp(ifname, "lo")) {
 191                         found_default = true;
 192                 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
 193                                 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
 194                                 &p.addr.s6_addr32[0], &p.addr.s6_addr32[1], &p.prefix, &rflags) &&
 195                                 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
 196                         // Find source prefixes by scanning through unreachable-routes
 197                         p.addr.s6_addr32[0] = htonl(p.addr.s6_addr32[0]);
 198                         p.addr.s6_addr32[1] = htonl(p.addr.s6_addr32[1]);
 199
 200                         for (ssize_t i = 0; i < len; ++i) {
 201                                 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
 202                                                 !odhcpd_bmemcmp(&p.addr, &n[i].addr, p.prefix)) {
 203                                         n[i].dprefix = p.prefix;
 204                                         break;
 205                                 }
 206                         }
 207
 208                 }
 209         }
 210
 211         return found_default;
 212 }
 213
 214 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
 215                 uint32_t *maxival)
 216 {
 217         uint32_t minival = iface->ra_mininterval;
 218         int msecs;
 219
 220         *maxival = iface->ra_maxinterval;
 221
 222         if (*maxival > minvalid/3)
 223                 *maxival = minvalid/3;
 224
 225         if (*maxival > MaxRtrAdvInterval)
 226                 *maxival = MaxRtrAdvInterval;
 227         else if (*maxival < 4)
 228                 *maxival = 4;
 229
 230         if (minival < MinRtrAdvInterval)
 231                 minival = MinRtrAdvInterval;
 232         else if (minival > (*maxival * 3)/4)
 233                 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
 234
 235         odhcpd_urandom(&msecs, sizeof(msecs));
 236         msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
 237                         minival*1000;
 238
 239         return msecs;
 240 }
 241
 242 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
 243 {
 244         uint16_t lifetime = 3*maxival;
 245
 246         if (iface->ra_lifetime >= 0) {
 247                 lifetime = iface->ra_lifetime;
 248                 if (lifetime < maxival)
 249                         lifetime = maxival;
 250                 else if (lifetime > 9000)
 251                         lifetime = 9000;
 252         }
 253
 254         return lifetime;
 255 }
 256
 257 enum {
 258         IOV_RA_ADV=0,
 259         IOV_RA_PFXS,
 260         IOV_RA_ROUTES,
 261         IOV_RA_DNS,
 262         IOV_RA_DNS_ADDR,
 263         IOV_RA_SEARCH,
 264         IOV_RA_ADV_INTERVAL,
 265         IOV_RA_TOTAL,
 266 };
 267
 268 // Router Advert server mode
 269 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
 270 {
 271         time_t now = odhcpd_time();
 272         int mtu = iface->ra_mtu;
 273         int hlim = iface->ra_hoplimit;
 274
 275         if (mtu == 0)
 276                 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
 277
 278         if (mtu < 1280)
 279                 mtu = 1280;
 280
 281         if (hlim == 0)
 282                 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
 283
 284         struct {
 285                 struct nd_router_advert h;
 286                 struct icmpv6_opt lladdr;
 287                 struct nd_opt_mtu mtu;
 288         } adv = {
 289                 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
 290                 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
 291                 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
 292         };
 293
 294         if (hlim > 0)
 295                 adv.h.nd_ra_curhoplimit = hlim;
 296
 297         if (iface->dhcpv6)
 298                 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
 299
 300         if (iface->managed >= RELAYD_MANAGED_MFLAG)
 301                 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
 302
 303         if (iface->route_preference < 0)
 304                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 305         else if (iface->route_preference > 0)
 306                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
 307
 308         adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
 309         adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
 310
 311         odhcpd_get_mac(iface, adv.lladdr.data);
 312
 313         // If not currently shutting down
 314         struct odhcpd_ipaddr *addrs = NULL;
 315         ssize_t ipcnt = 0;
 316         uint32_t minvalid = UINT32_MAX;
 317         bool default_route = false;
 318         bool valid_prefix = false;
 319
 320         // If not shutdown
 321         if (iface->timer_rs.cb) {
 322                 size_t size = sizeof(*addrs) * iface->ia_addr_len;
 323                 addrs = alloca(size);
 324                 memcpy(addrs, iface->ia_addr, size);
 325
 326                 ipcnt = iface->ia_addr_len;
 327
 328                 // Check default route
 329                 if (iface->default_router) {
 330                         default_route = true;
 331
 332                         if (iface->default_router > 1)
 333                                 valid_prefix = true;
 334                 } else if (parse_routes(addrs, ipcnt))
 335                         default_route = true;
 336         }
 337
 338
 339         struct in6_addr dns_pref, *dns_addr = &dns_pref;
 340         size_t dns_cnt = 1;
 341
 342         odhcpd_get_interface_dns_addr(iface, &dns_pref);
 343
 344         // Construct Prefix Information options
 345         size_t pfxs_cnt = 0;
 346         struct nd_opt_prefix_info *pfxs = NULL;
 347
 348         for (ssize_t i = 0; i < ipcnt; ++i) {
 349                 struct odhcpd_ipaddr *addr = &addrs[i];
 350                 uint32_t preferred = 0;
 351                 uint32_t valid = 0;
 352
 353                 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
 354                         char namebuf[INET6_ADDRSTRLEN];
 355
 356                         inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
 357                         syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
 358                                         namebuf, addr->prefix, addr->valid, iface->ifname);
 359                         continue;
 360                 }
 361
 362                 struct nd_opt_prefix_info *p = NULL;
 363                 for (size_t i = 0; i < pfxs_cnt; ++i) {
 364                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
 365                                         !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 366                                         &addr->addr, addr->prefix))
 367                                 p = &pfxs[i];
 368                 }
 369
 370                 if (!p) {
 371                         struct nd_opt_prefix_info *tmp;
 372
 373                         tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
 374                         if (!tmp) {
 375                                 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
 376                                 continue;
 377                         }
 378
 379                         pfxs = tmp;
 380                         p = &pfxs[pfxs_cnt++];
 381                         memset(p, 0, sizeof(*p));
 382                 }
 383
 384                 if (addr->preferred > (uint32_t)now) {
 385                         preferred = TIME_LEFT(addr->preferred, now);
 386
 387                         if (iface->ra_useleasetime &&
 388                                         preferred > iface->dhcpv4_leasetime)
 389                                 preferred = iface->dhcpv4_leasetime;
 390                 }
 391
 392                 valid = TIME_LEFT(addr->valid, now);
 393                 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
 394                         valid = iface->dhcpv4_leasetime;
 395
 396                 if (minvalid > valid)
 397                         minvalid = valid;
 398
 399                 if (!IN6_IS_ADDR_ULA(&addr->addr) || iface->default_router)
 400                         valid_prefix = true;
 401
 402                 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
 403                                 (iface->ra_advrouter) ? 128 : addr->prefix);
 404                 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 405                 p->nd_opt_pi_len = 4;
 406                 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 407                 p->nd_opt_pi_flags_reserved = 0;
 408                 if (!iface->ra_not_onlink)
 409                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
 410                 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
 411                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 412                 if (iface->ra_advrouter)
 413                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
 414                 p->nd_opt_pi_preferred_time = htonl(preferred);
 415                 p->nd_opt_pi_valid_time = htonl(valid);
 416         }
 417
 418         // Calculate periodic transmit
 419         uint32_t maxival;
 420         int msecs = calc_adv_interval(iface, minvalid, &maxival);
 421
 422         if (default_route) {
 423                 if (!valid_prefix) {
 424                         syslog(LOG_WARNING, "A default route is present but there is no public prefix "
 425                                         "on %s thus we don't announce a default route!", iface->ifname);
 426                         adv.h.nd_ra_router_lifetime = 0;
 427                 } else
 428                         adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
 429
 430         } else
 431                 adv.h.nd_ra_router_lifetime = 0;
 432
 433         syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
 434
 435         // DNS Recursive DNS
 436         if (iface->dns_cnt > 0) {
 437                 dns_addr = iface->dns;
 438                 dns_cnt = iface->dns_cnt;
 439         }
 440
 441         if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
 442                 dns_cnt = 0;
 443
 444         struct {
 445                 uint8_t type;
 446                 uint8_t len;
 447                 uint8_t pad;
 448                 uint8_t pad2;
 449                 uint32_t lifetime;
 450         } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
 451
 452         // DNS Search options
 453         uint8_t search_buf[256], *search_domain = iface->search;
 454         size_t search_len = iface->search_len, search_padded = 0;
 455
 456         if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 457                 int len = dn_comp(_res.dnsrch[0], search_buf,
 458                                 sizeof(search_buf), NULL, NULL);
 459                 if (len > 0) {
 460                         search_domain = search_buf;
 461                         search_len = len;
 462                 }
 463         }
 464
 465         if (search_len > 0)
 466                 search_padded = ((search_len + 7) & (~7)) + 8;
 467
 468         struct {
 469                 uint8_t type;
 470                 uint8_t len;
 471                 uint8_t pad;
 472                 uint8_t pad2;
 473                 uint32_t lifetime;
 474                 uint8_t name[];
 475         } *search = alloca(sizeof(*search) + search_padded);
 476
 477         search->type = ND_OPT_DNS_SEARCH;
 478         search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
 479         search->pad = 0;
 480         search->pad2 = 0;
 481         memcpy(search->name, search_domain, search_len);
 482         memset(&search->name[search_len], 0, search_padded - search_len);
 483
 484
 485         size_t routes_cnt = 0;
 486         struct {
 487                 uint8_t type;
 488                 uint8_t len;
 489                 uint8_t prefix;
 490                 uint8_t flags;
 491                 uint32_t lifetime;
 492                 uint32_t addr[4];
 493         } *tmp, *routes = NULL;
 494
 495         for (ssize_t i = 0; i < ipcnt; ++i) {
 496                 struct odhcpd_ipaddr *addr = &addrs[i];
 497                 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now ||
 498                                 (addr->dprefix == 64 && addr->prefix == 64)) {
 499                         continue; // Address not suitable
 500                 } else if (addr->dprefix > 32) {
 501                         addr->addr.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
 502                 } else if (addr->dprefix <= 32) {
 503                         addr->addr.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
 504                         addr->addr.s6_addr32[1] = 0;
 505                 }
 506
 507                 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
 508                 if (!tmp) {
 509                         syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
 510                         continue;
 511                 }
 512
 513                 routes = tmp;
 514
 515                 memset(&routes[routes_cnt], 0, sizeof(*routes));
 516                 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 517                 routes[routes_cnt].len = sizeof(*routes) / 8;
 518                 routes[routes_cnt].prefix = addr->dprefix;
 519                 routes[routes_cnt].flags = 0;
 520                 if (iface->route_preference < 0)
 521                         routes[routes_cnt].flags |= ND_RA_PREF_LOW;
 522                 else if (iface->route_preference > 0)
 523                         routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
 524                 routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now));
 525                 routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
 526                 routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
 527                 routes[routes_cnt].addr[2] = 0;
 528                 routes[routes_cnt].addr[3] = 0;
 529
 530                 ++routes_cnt;
 531         }
 532
 533         search->lifetime = htonl(maxival*10);
 534         dns.lifetime = search->lifetime;
 535
 536         struct icmpv6_opt adv_interval = {
 537                 .type = ND_OPT_RTR_ADV_INTERVAL,
 538                 .len = 1,
 539                 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
 540         };
 541
 542         struct iovec iov[IOV_RA_TOTAL] = {
 543                         [IOV_RA_ADV] = {&adv, sizeof(adv)},
 544                         [IOV_RA_PFXS] = {pfxs, pfxs_cnt * sizeof(*pfxs)},
 545                         [IOV_RA_ROUTES] = {routes, routes_cnt * sizeof(*routes)},
 546                         [IOV_RA_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
 547                         [IOV_RA_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)},
 548                         [IOV_RA_SEARCH] = {search, search->len * 8},
 549                         [IOV_RA_ADV_INTERVAL] = {&adv_interval, adv_interval.len * 8}};
 550         struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
 551
 552         if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
 553                 dest.sin6_addr = *from;
 554
 555         odhcpd_send(router_event.uloop.fd,
 556                         &dest, iov, ARRAY_SIZE(iov), iface);
 557
 558         free(pfxs);
 559         free(routes);
 560
 561         return msecs;
 562 }
 563
 564
 565 static void trigger_router_advert(struct uloop_timeout *event)
 566 {
 567         struct interface *iface = container_of(event, struct interface, timer_rs);
 568         int msecs = send_router_advert(iface, NULL);
 569
 570         // Rearm timer if not shut down
 571         if (event->cb)
 572                 uloop_timeout_set(event, msecs);
 573 }
 574
 575
 576 // Event handler for incoming ICMPv6 packets
 577 static void handle_icmpv6(void *addr, void *data, size_t len,
 578                 struct interface *iface, _unused void *dest)
 579 {
 580         struct icmp6_hdr *hdr = data;
 581         struct sockaddr_in6 *from = addr;
 582
 583         if (!router_icmpv6_valid(addr, data, len))
 584                 return;
 585
 586         if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
 587                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
 588                         send_router_advert(iface, &from->sin6_addr);
 589         } else if (iface->ra == RELAYD_RELAY) { // Relay mode
 590                 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
 591                         forward_router_advertisement(data, len);
 592                 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
 593                         forward_router_solicitation(odhcpd_get_master_interface());
 594         }
 595 }
 596
 597
 598 // Forward router solicitation
 599 static void forward_router_solicitation(const struct interface *iface)
 600 {
 601         if (!iface)
 602                 return;
 603
 604         struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
 605         struct iovec iov = {&rs, sizeof(rs)};
 606         struct sockaddr_in6 all_routers =
 607                 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
 608
 609         syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
 610         odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
 611 }
 612
 613
 614 // Handler for incoming router solicitations on slave interfaces
 615 static void forward_router_advertisement(uint8_t *data, size_t len)
 616 {
 617         struct nd_router_advert *adv = (struct nd_router_advert *)data;
 618
 619         // Rewrite options
 620         uint8_t *end = data + len;
 621         uint8_t *mac_ptr = NULL;
 622         struct in6_addr *dns_ptr = NULL;
 623         size_t dns_count = 0;
 624
 625         struct icmpv6_opt *opt;
 626         icmpv6_for_each_option(opt, &adv[1], end) {
 627                 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 628                         // Store address of source MAC-address
 629                         mac_ptr = opt->data;
 630                 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
 631                         // Check if we have to rewrite DNS
 632                         dns_ptr = (struct in6_addr*)&opt->data[6];
 633                         dns_count = (opt->len - 1) / 2;
 634                 }
 635         }
 636
 637         syslog(LOG_NOTICE, "Got a RA");
 638
 639         // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
 640         adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
 641
 642         // Forward advertisement to all slave interfaces
 643         struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
 644         struct iovec iov = {data, len};
 645
 646         struct interface *iface;
 647         list_for_each_entry(iface, &interfaces, head) {
 648                 if (iface->ra != RELAYD_RELAY || iface->master)
 649                         continue;
 650
 651                 // Fixup source hardware address option
 652                 if (mac_ptr)
 653                         odhcpd_get_mac(iface, mac_ptr);
 654
 655                 // If we have to rewrite DNS entries
 656                 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
 657                         const struct in6_addr *rewrite = iface->dns;
 658                         struct in6_addr addr;
 659                         size_t rewrite_cnt = iface->dns_cnt;
 660
 661                         if (rewrite_cnt == 0) {
 662                                 if (odhcpd_get_interface_dns_addr(iface, &addr))
 663                                         continue; // Unable to comply
 664
 665                                 rewrite = &addr;
 666                                 rewrite_cnt = 1;
 667                         }
 668
 669                         // Copy over any other addresses
 670                         for (size_t i = 0; i < dns_count; ++i) {
 671                                 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
 672                                 dns_ptr[i] = rewrite[j];
 673                         }
 674                 }
 675
 676                 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);
 677         }
 678 }