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