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                 }
 123
 124                 if (iface->ra == RELAYD_RELAY || (iface->ra == RELAYD_SERVER && !iface->master))
 125                         setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
 126                                         IPV6_ADD_MEMBERSHIP, mreq, sizeof(all_nodes));
 127         }
 128         return 0;
 129 }
 130
 131
 132 // Signal handler to resend all RDs
 133 static void sigusr1_refresh(_unused int signal)
 134 {
 135         struct interface *iface;
 136         list_for_each_entry(iface, &interfaces, head)
 137                 if (iface->ra == RELAYD_SERVER && !iface->master)
 138                         uloop_timeout_set(&iface->timer_rs, 1000);
 139 }
 140
 141 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
 142 {
 143         struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
 144         struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
 145
 146         /* Hoplimit is already checked in odhcpd_receive_packets */
 147         if (len < sizeof(*hdr) || hdr->icmp6_code)
 148                 return false;
 149
 150         switch (hdr->icmp6_type) {
 151         case ND_ROUTER_ADVERT:
 152                 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
 153                         return false;
 154
 155                 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
 156                 break;
 157
 158         case ND_ROUTER_SOLICIT:
 159                 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
 160                 break;
 161
 162         default:
 163                 return false;
 164         }
 165
 166         icmpv6_for_each_option(opt, opt, end)
 167                 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
 168                                 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
 169                                 hdr->icmp6_type == ND_ROUTER_SOLICIT)
 170                         return false;
 171
 172         // Check all options parsed successfully
 173         return opt == end;
 174 }
 175
 176
 177 // Detect whether a default route exists, also find the source prefixes
 178 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 179 {
 180         rewind(fp_route);
 181
 182         char line[512], ifname[16];
 183         bool found_default = false;
 184         struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0,
 185                                         .dprefix = 0, .preferred = 0, .valid = 0};
 186
 187         while (fgets(line, sizeof(line), fp_route)) {
 188                 uint32_t rflags;
 189                 if (sscanf(line, "00000000000000000000000000000000 00 "
 190                                 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
 191                                 strcmp(ifname, "lo")) {
 192                         found_default = true;
 193                 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
 194                                 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
 195                                 &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) &&
 196                                 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
 197                         // Find source prefixes by scanning through unreachable-routes
 198                         p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]);
 199                         p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]);
 200
 201                         for (ssize_t i = 0; i < len; ++i) {
 202                                 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
 203                                                 !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) {
 204                                         n[i].dprefix = p.prefix;
 205                                         break;
 206                                 }
 207                         }
 208
 209                 }
 210         }
 211
 212         return found_default;
 213 }
 214
 215 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
 216                 uint32_t *maxival)
 217 {
 218         uint32_t minival = iface->ra_mininterval;
 219         int msecs;
 220
 221         *maxival = iface->ra_maxinterval;
 222
 223         if (*maxival > minvalid/3)
 224                 *maxival = minvalid/3;
 225
 226         if (*maxival > MaxRtrAdvInterval)
 227                 *maxival = MaxRtrAdvInterval;
 228         else if (*maxival < 4)
 229                 *maxival = 4;
 230
 231         if (minival < MinRtrAdvInterval)
 232                 minival = MinRtrAdvInterval;
 233         else if (minival > (*maxival * 3)/4)
 234                 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
 235
 236         odhcpd_urandom(&msecs, sizeof(msecs));
 237         msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
 238                         minival*1000;
 239
 240         return msecs;
 241 }
 242
 243 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
 244 {
 245         uint16_t lifetime = 3*maxival;
 246
 247         if (iface->ra_lifetime >= 0) {
 248                 lifetime = iface->ra_lifetime;
 249                 if (lifetime < maxival)
 250                         lifetime = maxival;
 251                 else if (lifetime > 9000)
 252                         lifetime = 9000;
 253         }
 254
 255         return lifetime;
 256 }
 257
 258 enum {
 259         IOV_RA_ADV=0,
 260         IOV_RA_PFXS,
 261         IOV_RA_ROUTES,
 262         IOV_RA_DNS,
 263         IOV_RA_DNS_ADDR,
 264         IOV_RA_SEARCH,
 265         IOV_RA_ADV_INTERVAL,
 266         IOV_RA_TOTAL,
 267 };
 268
 269 // Router Advert server mode
 270 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
 271 {
 272         time_t now = odhcpd_time();
 273         int mtu = iface->ra_mtu;
 274         int hlim = iface->ra_hoplimit;
 275
 276         if (mtu == 0)
 277                 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
 278
 279         if (mtu < 1280)
 280                 mtu = 1280;
 281
 282         if (hlim == 0)
 283                 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
 284
 285         struct {
 286                 struct nd_router_advert h;
 287                 struct icmpv6_opt lladdr;
 288                 struct nd_opt_mtu mtu;
 289         } adv = {
 290                 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
 291                 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
 292                 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
 293         };
 294
 295         if (hlim > 0)
 296                 adv.h.nd_ra_curhoplimit = hlim;
 297
 298         if (iface->dhcpv6)
 299                 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
 300
 301         if (iface->ra_managed >= RA_MANAGED_MFLAG)
 302                 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
 303
 304         if (iface->route_preference < 0)
 305                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
 306         else if (iface->route_preference > 0)
 307                 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
 308
 309         adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
 310         adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
 311
 312         odhcpd_get_mac(iface, adv.lladdr.data);
 313
 314         // If not currently shutting down
 315         struct odhcpd_ipaddr *addrs = NULL;
 316         ssize_t ipcnt = 0;
 317         uint32_t minvalid = UINT32_MAX;
 318         bool default_route = false;
 319         bool valid_prefix = false;
 320
 321         // If not shutdown
 322         if (iface->timer_rs.cb) {
 323                 size_t size = sizeof(*addrs) * iface->ia_addr_len;
 324                 addrs = alloca(size);
 325                 memcpy(addrs, iface->ia_addr, size);
 326
 327                 ipcnt = iface->ia_addr_len;
 328
 329                 // Check default route
 330                 if (iface->default_router) {
 331                         default_route = true;
 332
 333                         if (iface->default_router > 1)
 334                                 valid_prefix = true;
 335                 } else if (parse_routes(addrs, ipcnt))
 336                         default_route = true;
 337         }
 338
 339
 340         struct in6_addr dns_pref, *dns_addr = &dns_pref;
 341         size_t dns_cnt = 1;
 342
 343         odhcpd_get_interface_dns_addr(iface, &dns_pref);
 344
 345         // Construct Prefix Information options
 346         size_t pfxs_cnt = 0;
 347         struct nd_opt_prefix_info *pfxs = NULL;
 348
 349         for (ssize_t i = 0; i < ipcnt; ++i) {
 350                 struct odhcpd_ipaddr *addr = &addrs[i];
 351                 uint32_t preferred = 0;
 352                 uint32_t valid = 0;
 353
 354                 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
 355                         char namebuf[INET6_ADDRSTRLEN];
 356
 357                         inet_ntop(AF_INET6, &addr->addr.in6, namebuf, sizeof(namebuf));
 358                         syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
 359                                         namebuf, addr->prefix, addr->valid, iface->ifname);
 360                         continue;
 361                 }
 362
 363                 struct nd_opt_prefix_info *p = NULL;
 364                 for (size_t i = 0; i < pfxs_cnt; ++i) {
 365                         if (addr->prefix == pfxs[i].nd_opt_pi_prefix_len &&
 366                                         !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
 367                                         &addr->addr.in6, addr->prefix))
 368                                 p = &pfxs[i];
 369                 }
 370
 371                 if (!p) {
 372                         struct nd_opt_prefix_info *tmp;
 373
 374                         tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
 375                         if (!tmp) {
 376                                 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
 377                                 continue;
 378                         }
 379
 380                         pfxs = tmp;
 381                         p = &pfxs[pfxs_cnt++];
 382                         memset(p, 0, sizeof(*p));
 383                 }
 384
 385                 if (addr->preferred > (uint32_t)now) {
 386                         preferred = TIME_LEFT(addr->preferred, now);
 387
 388                         if (iface->ra_useleasetime &&
 389                                         preferred > iface->dhcpv4_leasetime)
 390                                 preferred = iface->dhcpv4_leasetime;
 391                 }
 392
 393                 valid = TIME_LEFT(addr->valid, now);
 394                 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
 395                         valid = iface->dhcpv4_leasetime;
 396
 397                 if (minvalid > valid)
 398                         minvalid = valid;
 399
 400                 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
 401                         valid_prefix = true;
 402
 403                 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr.in6,
 404                                 (iface->ra_advrouter) ? 128 : addr->prefix);
 405                 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
 406                 p->nd_opt_pi_len = 4;
 407                 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
 408                 p->nd_opt_pi_flags_reserved = 0;
 409                 if (!iface->ra_not_onlink)
 410                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
 411                 if (iface->ra_managed < RA_MANAGED_NO_AFLAG && addr->prefix <= 64)
 412                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
 413                 if (iface->ra_advrouter)
 414                         p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
 415                 p->nd_opt_pi_preferred_time = htonl(preferred);
 416                 p->nd_opt_pi_valid_time = htonl(valid);
 417         }
 418
 419         // Calculate periodic transmit
 420         uint32_t maxival;
 421         int msecs = calc_adv_interval(iface, minvalid, &maxival);
 422
 423         if (default_route) {
 424                 if (!valid_prefix) {
 425                         syslog(LOG_WARNING, "A default route is present but there is no public prefix "
 426                                         "on %s thus we don't announce a default route!", iface->ifname);
 427                         adv.h.nd_ra_router_lifetime = 0;
 428                 } else
 429                         adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
 430
 431         } else
 432                 adv.h.nd_ra_router_lifetime = 0;
 433
 434         syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
 435
 436         // DNS Recursive DNS
 437         if (iface->dns_cnt > 0) {
 438                 dns_addr = iface->dns;
 439                 dns_cnt = iface->dns_cnt;
 440         }
 441
 442         if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
 443                 dns_cnt = 0;
 444
 445         struct {
 446                 uint8_t type;
 447                 uint8_t len;
 448                 uint8_t pad;
 449                 uint8_t pad2;
 450                 uint32_t lifetime;
 451         } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
 452
 453         // DNS Search options
 454         uint8_t search_buf[256], *search_domain = iface->search;
 455         size_t search_len = iface->search_len, search_padded = 0;
 456
 457         if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
 458                 int len = dn_comp(_res.dnsrch[0], search_buf,
 459                                 sizeof(search_buf), NULL, NULL);
 460                 if (len > 0) {
 461                         search_domain = search_buf;
 462                         search_len = len;
 463                 }
 464         }
 465
 466         if (search_len > 0)
 467                 search_padded = ((search_len + 7) & (~7)) + 8;
 468
 469         struct {
 470                 uint8_t type;
 471                 uint8_t len;
 472                 uint8_t pad;
 473                 uint8_t pad2;
 474                 uint32_t lifetime;
 475                 uint8_t name[];
 476         } *search = alloca(sizeof(*search) + search_padded);
 477
 478         search->type = ND_OPT_DNS_SEARCH;
 479         search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
 480         search->pad = 0;
 481         search->pad2 = 0;
 482         memcpy(search->name, search_domain, search_len);
 483         memset(&search->name[search_len], 0, search_padded - search_len);
 484
 485
 486         size_t routes_cnt = 0;
 487         struct {
 488                 uint8_t type;
 489                 uint8_t len;
 490                 uint8_t prefix;
 491                 uint8_t flags;
 492                 uint32_t lifetime;
 493                 uint32_t addr[4];
 494         } *tmp, *routes = NULL;
 495
 496         for (ssize_t i = 0; i < ipcnt; ++i) {
 497                 struct odhcpd_ipaddr *addr = &addrs[i];
 498                 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now ||
 499                                 (addr->dprefix == 64 && addr->prefix == 64)) {
 500                         continue; // Address not suitable
 501                 } else if (addr->dprefix > 32) {
 502                         addr->addr.in6.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
 503                 } else if (addr->dprefix <= 32) {
 504                         addr->addr.in6.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
 505                         addr->addr.in6.s6_addr32[1] = 0;
 506                 }
 507
 508                 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
 509                 if (!tmp) {
 510                         syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
 511                         continue;
 512                 }
 513
 514                 routes = tmp;
 515
 516                 memset(&routes[routes_cnt], 0, sizeof(*routes));
 517                 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
 518                 routes[routes_cnt].len = sizeof(*routes) / 8;
 519                 routes[routes_cnt].prefix = addr->dprefix;
 520                 routes[routes_cnt].flags = 0;
 521                 if (iface->route_preference < 0)
 522                         routes[routes_cnt].flags |= ND_RA_PREF_LOW;
 523                 else if (iface->route_preference > 0)
 524                         routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
 525                 routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now));
 526                 routes[routes_cnt].addr[0] = addr->addr.in6.s6_addr32[0];
 527                 routes[routes_cnt].addr[1] = addr->addr.in6.s6_addr32[1];
 528                 routes[routes_cnt].addr[2] = 0;
 529                 routes[routes_cnt].addr[3] = 0;
 530
 531                 ++routes_cnt;
 532         }
 533
 534         search->lifetime = htonl(maxival*10);
 535         dns.lifetime = search->lifetime;
 536
 537         struct icmpv6_opt adv_interval = {
 538                 .type = ND_OPT_RTR_ADV_INTERVAL,
 539                 .len = 1,
 540                 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
 541         };
 542
 543         struct iovec iov[IOV_RA_TOTAL] = {
 544                         [IOV_RA_ADV] = {&adv, sizeof(adv)},
 545                         [IOV_RA_PFXS] = {pfxs, pfxs_cnt * sizeof(*pfxs)},
 546                         [IOV_RA_ROUTES] = {routes, routes_cnt * sizeof(*routes)},
 547                         [IOV_RA_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
 548                         [IOV_RA_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)},
 549                         [IOV_RA_SEARCH] = {search, search->len * 8},
 550                         [IOV_RA_ADV_INTERVAL] = {&adv_interval, adv_interval.len * 8}};
 551         struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
 552
 553         if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
 554                 dest.sin6_addr = *from;
 555
 556         odhcpd_send(router_event.uloop.fd,
 557                         &dest, iov, ARRAY_SIZE(iov), iface);
 558
 559         free(pfxs);
 560         free(routes);
 561
 562         return msecs;
 563 }
 564
 565
 566 static void trigger_router_advert(struct uloop_timeout *event)
 567 {
 568         struct interface *iface = container_of(event, struct interface, timer_rs);
 569         int msecs = send_router_advert(iface, NULL);
 570
 571         // Rearm timer if not shut down
 572         if (event->cb)
 573                 uloop_timeout_set(event, msecs);
 574 }
 575
 576
 577 // Event handler for incoming ICMPv6 packets
 578 static void handle_icmpv6(void *addr, void *data, size_t len,
 579                 struct interface *iface, _unused void *dest)
 580 {
 581         struct icmp6_hdr *hdr = data;
 582         struct sockaddr_in6 *from = addr;
 583
 584         if (!router_icmpv6_valid(addr, data, len))
 585                 return;
 586
 587         if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
 588                 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
 589                         send_router_advert(iface, &from->sin6_addr);
 590         } else if (iface->ra == RELAYD_RELAY) { // Relay mode
 591                 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
 592                         forward_router_advertisement(data, len);
 593                 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
 594                         forward_router_solicitation(odhcpd_get_master_interface());
 595         }
 596 }
 597
 598
 599 // Forward router solicitation
 600 static void forward_router_solicitation(const struct interface *iface)
 601 {
 602         if (!iface)
 603                 return;
 604
 605         struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
 606         struct iovec iov = {&rs, sizeof(rs)};
 607         struct sockaddr_in6 all_routers =
 608                 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
 609
 610         syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
 611         odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
 612 }
 613
 614
 615 // Handler for incoming router solicitations on slave interfaces
 616 static void forward_router_advertisement(uint8_t *data, size_t len)
 617 {
 618         struct nd_router_advert *adv = (struct nd_router_advert *)data;
 619
 620         // Rewrite options
 621         uint8_t *end = data + len;
 622         uint8_t *mac_ptr = NULL;
 623         struct in6_addr *dns_ptr = NULL;
 624         size_t dns_count = 0;
 625
 626         struct icmpv6_opt *opt;
 627         icmpv6_for_each_option(opt, &adv[1], end) {
 628                 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
 629                         // Store address of source MAC-address
 630                         mac_ptr = opt->data;
 631                 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
 632                         // Check if we have to rewrite DNS
 633                         dns_ptr = (struct in6_addr*)&opt->data[6];
 634                         dns_count = (opt->len - 1) / 2;
 635                 }
 636         }
 637
 638         syslog(LOG_NOTICE, "Got a RA");
 639
 640         // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
 641         adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
 642
 643         // Forward advertisement to all slave interfaces
 644         struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
 645         struct iovec iov = {data, len};
 646
 647         struct interface *iface;
 648         list_for_each_entry(iface, &interfaces, head) {
 649                 if (iface->ra != RELAYD_RELAY || iface->master)
 650                         continue;
 651
 652                 // Fixup source hardware address option
 653                 if (mac_ptr)
 654                         odhcpd_get_mac(iface, mac_ptr);
 655
 656                 // If we have to rewrite DNS entries
 657                 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
 658                         const struct in6_addr *rewrite = iface->dns;
 659                         struct in6_addr addr;
 660                         size_t rewrite_cnt = iface->dns_cnt;
 661
 662                         if (rewrite_cnt == 0) {
 663                                 if (odhcpd_get_interface_dns_addr(iface, &addr))
 664                                         continue; // Unable to comply
 665
 666                                 rewrite = &addr;
 667                                 rewrite_cnt = 1;
 668                         }
 669
 670                         // Copy over any other addresses
 671                         for (size_t i = 0; i < dns_count; ++i) {
 672                                 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
 673                                 dns_ptr[i] = rewrite[j];
 674                         }
 675                 }
 676
 677                 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);
 678         }
 679 }