2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
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.
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.
23 #include <net/route.h>
29 static void forward_router_solicitation(const struct interface *iface);
30 static void forward_router_advertisement(uint8_t *data, size_t len);
32 static void handle_icmpv6(void *addr, void *data, size_t len,
33 struct interface *iface, void *dest);
34 static void trigger_router_advert(struct uloop_timeout *event);
35 static void sigusr1_refresh(int signal);
37 static struct odhcpd_event router_event = {{.fd = -1}, handle_icmpv6};
39 static FILE *fp_route = NULL;
46 int sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
47 if (sock < 0 && errno != EAFNOSUPPORT) {
48 syslog(LOG_ERR, "Failed to open RAW-socket: %s", strerror(errno));
52 // Let the kernel compute our checksums
54 setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
56 // This is required by RFC 4861
58 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
59 setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
61 // We need to know the source interface
63 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
64 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
68 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
70 // Filter ICMPv6 package types
71 struct icmp6_filter filt;
72 ICMP6_FILTER_SETBLOCKALL(&filt);
73 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
74 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
75 setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt, sizeof(filt));
78 router_event.uloop.fd = sock;
79 odhcpd_register(&router_event);
81 if (!(fp_route = fopen("/proc/net/ipv6_route", "r")))
82 syslog(LOG_ERR, "Failed to open routing table: %s",
85 signal(SIGUSR1, sigusr1_refresh);
90 int setup_router_interface(struct interface *iface, bool enable)
92 if (!fp_route || router_event.uloop.fd < 0)
95 struct ipv6_mreq all_nodes = {ALL_IPV6_NODES, iface->ifindex};
96 struct ipv6_mreq all_routers = {ALL_IPV6_ROUTERS, iface->ifindex};
98 uloop_timeout_cancel(&iface->timer_rs);
99 iface->timer_rs.cb = NULL;
101 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
102 &all_nodes, sizeof(all_nodes));
103 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
104 &all_routers, sizeof(all_routers));
108 trigger_router_advert(&iface->timer_rs);
110 void *mreq = &all_routers;
112 if (iface->ra == RELAYD_RELAY && iface->master) {
114 forward_router_solicitation(iface);
115 } else if (iface->ra == RELAYD_SERVER && !iface->master) {
116 iface->timer_rs.cb = trigger_router_advert;
117 trigger_router_advert(&iface->timer_rs);
120 if (iface->ra == RELAYD_RELAY || (iface->ra == RELAYD_SERVER && !iface->master))
121 setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
122 IPV6_ADD_MEMBERSHIP, mreq, sizeof(all_nodes));
128 // Signal handler to resend all RDs
129 static void sigusr1_refresh(_unused int signal)
131 struct interface *iface;
132 list_for_each_entry(iface, &interfaces, head)
133 if (iface->ra == RELAYD_SERVER && !iface->master)
134 uloop_timeout_set(&iface->timer_rs, 1000);
137 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
139 struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
140 struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
142 /* Hoplimit is already checked in odhcpd_receive_packets */
143 if (len < sizeof(*hdr) || hdr->icmp6_code)
146 switch (hdr->icmp6_type) {
147 case ND_ROUTER_ADVERT:
148 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
151 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
154 case ND_ROUTER_SOLICIT:
155 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
162 icmpv6_for_each_option(opt, opt, end)
163 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
164 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
165 hdr->icmp6_type == ND_ROUTER_SOLICIT)
168 // Check all options parsed successfully
173 // Detect whether a default route exists, also find the source prefixes
174 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
178 char line[512], ifname[16];
179 bool found_default = false;
180 struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, 0, 0, 0};
181 while (fgets(line, sizeof(line), fp_route)) {
183 if (sscanf(line, "00000000000000000000000000000000 00 "
184 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
185 strcmp(ifname, "lo")) {
186 found_default = true;
187 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
188 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
189 &p.addr.s6_addr32[0], &p.addr.s6_addr32[1], &p.prefix, &rflags) &&
190 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
191 // Find source prefixes by scanning through unreachable-routes
192 p.addr.s6_addr32[0] = htonl(p.addr.s6_addr32[0]);
193 p.addr.s6_addr32[1] = htonl(p.addr.s6_addr32[1]);
195 for (ssize_t i = 0; i < len; ++i) {
196 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
197 !odhcpd_bmemcmp(&p.addr, &n[i].addr, p.prefix)) {
198 n[i].dprefix = p.prefix;
206 return found_default;
210 static void send_neigh_ra(const struct in6_addr *addr,
211 const struct interface *iface, void *data)
213 struct sockaddr_in6 dest = {
214 .sin6_family = AF_INET6,
216 .sin6_scope_id = iface->ifindex,
218 odhcpd_send(router_event.uloop.fd, &dest, data, RA_IOV_LEN, iface);
222 // Router Advert server mode
223 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
225 int mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
226 int hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
232 struct nd_router_advert h;
233 struct icmpv6_opt lladdr;
234 struct nd_opt_mtu mtu;
235 struct nd_opt_prefix_info prefix[RELAYD_MAX_PREFIXES];
237 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
238 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
239 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
243 adv.h.nd_ra_curhoplimit = hlim;
246 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
248 if (iface->managed >= RELAYD_MANAGED_MFLAG)
249 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
251 if (iface->route_preference < 0)
252 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
253 else if (iface->route_preference > 0)
254 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
255 odhcpd_get_mac(iface, adv.lladdr.data);
257 // If not currently shutting down
258 struct odhcpd_ipaddr addrs[RELAYD_MAX_PREFIXES];
260 uint64_t maxpreferred = 0;
263 if (iface->timer_rs.cb) {
264 ipcnt = odhcpd_get_interface_addresses(iface->ifindex,
265 addrs, ARRAY_SIZE(addrs));
267 // Check default route
268 if (parse_routes(addrs, ipcnt) || iface->default_router > 1)
269 adv.h.nd_ra_router_lifetime =
270 htons(3 * MaxRtrAdvInterval);
273 // Construct Prefix Information options
274 bool have_public = false;
277 struct in6_addr dns_pref = IN6ADDR_ANY_INIT, *dns_addr = &dns_pref;
278 uint32_t dns_time = 0;
281 for (ssize_t i = 0; i < ipcnt; ++i) {
282 struct odhcpd_ipaddr *addr = &addrs[i];
283 if (addr->prefix > 96)
284 continue; // Address not suitable
286 if (addr->preferred > MaxPreferredTime)
287 addr->preferred = MaxPreferredTime;
289 if (addr->valid > MaxValidTime)
290 addr->valid = MaxValidTime;
292 struct nd_opt_prefix_info *p = NULL;
293 for (size_t i = 0; i < cnt; ++i) {
294 if (addr->prefix == adv.prefix[i].nd_opt_pi_prefix_len &&
295 !odhcpd_bmemcmp(&adv.prefix[i].nd_opt_pi_prefix,
296 &addr->addr, addr->prefix))
301 if (cnt >= ARRAY_SIZE(adv.prefix))
304 p = &adv.prefix[cnt++];
307 if ((addr->addr.s6_addr[0] & 0xfe) != 0xfc && addr->preferred > 0) {
310 if (maxpreferred < 1000 * addr->preferred)
311 maxpreferred = 1000 * addr->preferred;
314 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
315 (iface->ra_advrouter) ? 128 : addr->prefix);
316 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
317 p->nd_opt_pi_len = 4;
318 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
319 p->nd_opt_pi_flags_reserved = 0;
320 if (!iface->ra_not_onlink)
321 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
322 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
323 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
324 if (iface->ra_advrouter)
325 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
326 p->nd_opt_pi_valid_time = htonl(addr->valid);
327 p->nd_opt_pi_preferred_time = htonl(addr->preferred);
329 if (addr->preferred > dns_time) {
330 dns_time = addr->preferred;
331 dns_pref = addr->addr;
335 if (!have_public && !iface->default_router && adv.h.nd_ra_router_lifetime) {
336 syslog(LOG_WARNING, "A default route is present but there is no public prefix "
337 "on %s thus we don't announce a default route!", iface->ifname);
338 adv.h.nd_ra_router_lifetime = 0;
342 if (iface->dns_cnt > 0) {
343 dns_addr = iface->dns;
344 dns_cnt = iface->dns_cnt;
345 dns_time = 2 * MaxRtrAdvInterval;
348 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
357 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
361 // DNS Search options
362 uint8_t search_buf[256], *search_domain = iface->search;
363 size_t search_len = iface->search_len, search_padded = 0;
365 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
366 int len = dn_comp(_res.dnsrch[0], search_buf,
367 sizeof(search_buf), NULL, NULL);
369 search_domain = search_buf;
375 search_padded = ((search_len + 7) & (~7)) + 8;
384 } *search = alloca(sizeof(*search) + search_padded);
386 search->type = ND_OPT_DNS_SEARCH;
387 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
390 search->lifetime = htonl(2 * MaxRtrAdvInterval);;
391 memcpy(search->name, search_domain, search_len);
392 memset(&search->name[search_len], 0, search_padded - search_len);
395 size_t routes_cnt = 0;
403 } routes[RELAYD_MAX_PREFIXES];
405 for (ssize_t i = 0; i < ipcnt; ++i) {
406 struct odhcpd_ipaddr *addr = &addrs[i];
407 if (addr->dprefix > 64 || addr->dprefix == 0 ||
408 (addr->dprefix == 64 && addr->prefix == 64)) {
409 continue; // Address not suitable
410 } else if (addr->dprefix > 32) {
411 addr->addr.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
412 } else if (addr->dprefix <= 32) {
413 addr->addr.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
414 addr->addr.s6_addr32[1] = 0;
417 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
418 routes[routes_cnt].len = sizeof(*routes) / 8;
419 routes[routes_cnt].prefix = addr->dprefix;
420 routes[routes_cnt].flags = 0;
421 if (iface->route_preference < 0)
422 routes[routes_cnt].flags |= ND_RA_PREF_LOW;
423 else if (iface->route_preference > 0)
424 routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
425 routes[routes_cnt].lifetime = htonl(addr->valid);
426 routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
427 routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
428 routes[routes_cnt].addr[2] = 0;
429 routes[routes_cnt].addr[3] = 0;
434 // Calculate periodic transmit
436 uint32_t maxival = MaxRtrAdvInterval * 1000;
437 uint32_t minival = MinRtrAdvInterval * 1000;
439 if (maxpreferred > 0 && maxival > maxpreferred / 2) {
440 maxival = maxpreferred / 2;
445 minival = maxival / 3;
447 minival = (maxival * 3) / 4;
450 odhcpd_urandom(&msecs, sizeof(msecs));
451 msecs = (labs(msecs) % (maxival - minival)) + minival;
453 struct icmpv6_opt adv_interval = {
454 .type = ND_OPT_RTR_ADV_INTERVAL,
456 .data = {0, 0, maxival >> 24, maxival >> 16, maxival >> 8, maxival}
459 struct iovec iov[RA_IOV_LEN] = {
460 {&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
461 {&routes, routes_cnt * sizeof(*routes)},
462 {&dns, (dns_cnt) ? sizeof(dns) : 0},
463 {dns_addr, dns_cnt * sizeof(*dns_addr)},
464 {search, search->len * 8},
465 {&adv_interval, adv_interval.len * 8}};
466 struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
468 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
469 dest.sin6_addr = *from;
471 odhcpd_send(router_event.uloop.fd,
472 &dest, iov, ARRAY_SIZE(iov), iface);
474 odhcpd_iterate_interface_neighbors(iface, send_neigh_ra, iov);
479 static void trigger_router_advert(struct uloop_timeout *event)
481 struct interface *iface = container_of(event, struct interface, timer_rs);
482 int msecs = send_router_advert(iface, NULL);
484 // Rearm timer if not shut down
486 uloop_timeout_set(event, msecs);
490 // Event handler for incoming ICMPv6 packets
491 static void handle_icmpv6(void *addr, void *data, size_t len,
492 struct interface *iface, _unused void *dest)
494 struct icmp6_hdr *hdr = data;
495 struct sockaddr_in6 *from = addr;
497 if (!router_icmpv6_valid(addr, data, len))
500 if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
501 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
502 send_router_advert(iface, &from->sin6_addr);
503 } else if (iface->ra == RELAYD_RELAY) { // Relay mode
504 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
505 forward_router_advertisement(data, len);
506 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
507 forward_router_solicitation(odhcpd_get_master_interface());
512 // Forward router solicitation
513 static void forward_router_solicitation(const struct interface *iface)
518 struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
519 struct iovec iov = {&rs, sizeof(rs)};
520 struct sockaddr_in6 all_routers =
521 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
523 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
524 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
528 // Handler for incoming router solicitations on slave interfaces
529 static void forward_router_advertisement(uint8_t *data, size_t len)
531 struct nd_router_advert *adv = (struct nd_router_advert *)data;
534 uint8_t *end = data + len;
535 uint8_t *mac_ptr = NULL;
536 struct in6_addr *dns_ptr = NULL;
537 size_t dns_count = 0;
539 struct icmpv6_opt *opt;
540 icmpv6_for_each_option(opt, &adv[1], end) {
541 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
542 // Store address of source MAC-address
544 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
545 // Check if we have to rewrite DNS
546 dns_ptr = (struct in6_addr*)&opt->data[6];
547 dns_count = (opt->len - 1) / 2;
551 syslog(LOG_NOTICE, "Got a RA");
553 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
554 adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
556 // Forward advertisement to all slave interfaces
557 struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
558 struct iovec iov = {data, len};
560 struct interface *iface;
561 list_for_each_entry(iface, &interfaces, head) {
562 if (iface->ra != RELAYD_RELAY || iface->master)
565 // Fixup source hardware address option
567 odhcpd_get_mac(iface, mac_ptr);
569 // If we have to rewrite DNS entries
570 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
571 const struct in6_addr *rewrite = iface->dns;
572 struct in6_addr addr;
573 size_t rewrite_cnt = iface->dns_cnt;
575 if (rewrite_cnt == 0) {
576 if (odhcpd_get_preferred_interface_address(iface->ifindex, &addr) < 1)
577 continue; // Unable to comply
583 // Copy over any other addresses
584 for (size_t i = 0; i < dns_count; ++i) {
585 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
586 dns_ptr[i] = rewrite[j];
590 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);