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 uloop_timeout_set(&iface->timer_rs, 1000);
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;
209 // Router Advert server mode
210 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
212 time_t now = odhcpd_time();
213 int mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
214 int hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
220 struct nd_router_advert h;
221 struct icmpv6_opt lladdr;
222 struct nd_opt_mtu mtu;
223 struct nd_opt_prefix_info prefix[sizeof(iface->ia_addr) / sizeof(*iface->ia_addr)];
225 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
226 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
227 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
231 adv.h.nd_ra_curhoplimit = hlim;
234 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
236 if (iface->managed >= RELAYD_MANAGED_MFLAG)
237 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
239 if (iface->route_preference < 0)
240 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
241 else if (iface->route_preference > 0)
242 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
243 odhcpd_get_mac(iface, adv.lladdr.data);
245 // If not currently shutting down
246 struct odhcpd_ipaddr *addrs = NULL;
248 int64_t minvalid = INT64_MAX;
249 int64_t maxvalid = 0;
252 if (iface->timer_rs.cb) {
253 addrs = iface->ia_addr;
254 ipcnt = iface->ia_addr_len;
256 // Check default route
257 if (parse_routes(addrs, ipcnt))
258 adv.h.nd_ra_router_lifetime = htons(1);
259 if (iface->default_router > 1)
260 adv.h.nd_ra_router_lifetime = htons(iface->default_router);
263 // Construct Prefix Information options
266 struct in6_addr dns_pref = IN6ADDR_ANY_INIT, *dns_addr = &dns_pref;
267 uint32_t dns_time = 0;
270 for (ssize_t i = 0; i < ipcnt; ++i) {
271 struct odhcpd_ipaddr *addr = &addrs[i];
272 if (addr->prefix > 96 || addr->valid <= (uint32_t)now)
273 continue; // Address not suitable
275 struct nd_opt_prefix_info *p = NULL;
276 for (size_t i = 0; i < cnt; ++i) {
277 if (addr->prefix == adv.prefix[i].nd_opt_pi_prefix_len &&
278 !odhcpd_bmemcmp(&adv.prefix[i].nd_opt_pi_prefix,
279 &addr->addr, addr->prefix))
284 if (cnt >= ARRAY_SIZE(adv.prefix))
287 p = &adv.prefix[cnt++];
290 if (addr->preferred > (uint32_t)now &&
291 minvalid > 1000LL * (addr->valid - now))
292 minvalid = 1000LL * (addr->valid - now);
294 if (maxvalid < 1000LL * (addr->valid - now))
295 maxvalid = 1000LL * (addr->valid - now);
297 if (((addr->addr.s6_addr[0] & 0xfe) != 0xfc || iface->default_router)
298 && ntohs(adv.h.nd_ra_router_lifetime) < addr->valid - now)
299 adv.h.nd_ra_router_lifetime = htons(addr->valid - now);
301 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
302 (iface->ra_advrouter) ? 128 : addr->prefix);
303 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
304 p->nd_opt_pi_len = 4;
305 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
306 p->nd_opt_pi_flags_reserved = 0;
307 if (!iface->ra_not_onlink)
308 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
309 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
310 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
311 if (iface->ra_advrouter)
312 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
313 p->nd_opt_pi_valid_time = htonl(addr->valid - now);
314 if (addr->preferred > (uint32_t)now)
315 p->nd_opt_pi_preferred_time = htonl(addr->preferred - now);
318 if (addr->preferred - now > dns_time) {
319 dns_time = addr->preferred - now;
320 dns_pref = addr->addr;
324 if (!iface->default_router && ntohs(adv.h.nd_ra_router_lifetime) == 1) {
325 syslog(LOG_WARNING, "A default route is present but there is no public prefix "
326 "on %s thus we don't announce a default route!", iface->ifname);
327 adv.h.nd_ra_router_lifetime = 0;
331 if (iface->dns_cnt > 0) {
332 dns_addr = iface->dns;
333 dns_cnt = iface->dns_cnt;
337 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
346 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
350 // DNS Search options
351 uint8_t search_buf[256], *search_domain = iface->search;
352 size_t search_len = iface->search_len, search_padded = 0;
354 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
355 int len = dn_comp(_res.dnsrch[0], search_buf,
356 sizeof(search_buf), NULL, NULL);
358 search_domain = search_buf;
364 search_padded = ((search_len + 7) & (~7)) + 8;
373 } *search = alloca(sizeof(*search) + search_padded);
375 search->type = ND_OPT_DNS_SEARCH;
376 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
379 memcpy(search->name, search_domain, search_len);
380 memset(&search->name[search_len], 0, search_padded - search_len);
383 size_t routes_cnt = 0;
391 } routes[RELAYD_MAX_PREFIXES];
393 for (ssize_t i = 0; i < ipcnt; ++i) {
394 struct odhcpd_ipaddr *addr = &addrs[i];
395 if (addr->dprefix > 64 || addr->dprefix == 0 || addr->valid <= (uint32_t)now ||
396 (addr->dprefix == 64 && addr->prefix == 64)) {
397 continue; // Address not suitable
398 } else if (addr->dprefix > 32) {
399 addr->addr.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
400 } else if (addr->dprefix <= 32) {
401 addr->addr.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
402 addr->addr.s6_addr32[1] = 0;
405 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
406 routes[routes_cnt].len = sizeof(*routes) / 8;
407 routes[routes_cnt].prefix = addr->dprefix;
408 routes[routes_cnt].flags = 0;
409 if (iface->route_preference < 0)
410 routes[routes_cnt].flags |= ND_RA_PREF_LOW;
411 else if (iface->route_preference > 0)
412 routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
413 routes[routes_cnt].lifetime = htonl(addr->valid - now);
414 routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
415 routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
416 routes[routes_cnt].addr[2] = 0;
417 routes[routes_cnt].addr[3] = 0;
422 // Calculate periodic transmit
424 uint32_t maxival = iface->ra_maxinterval * 1000;
427 if (maxival < 4000 || maxival > MaxRtrAdvInterval * 1000)
428 maxival = MaxRtrAdvInterval * 1000;
430 if (maxival > minvalid / 3) {
431 maxival = minvalid / 3;
437 minival = (maxival * 3) / 4;
439 search->lifetime = htonl(maxvalid / 1000);
442 dns.lifetime = search->lifetime;
444 odhcpd_urandom(&msecs, sizeof(msecs));
445 msecs = (labs(msecs) % (maxival - minival)) + minival;
447 struct icmpv6_opt adv_interval = {
448 .type = ND_OPT_RTR_ADV_INTERVAL,
450 .data = {0, 0, maxival >> 24, maxival >> 16, maxival >> 8, maxival}
453 struct iovec iov[RA_IOV_LEN] = {
454 {&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
455 {&routes, routes_cnt * sizeof(*routes)},
456 {&dns, (dns_cnt) ? sizeof(dns) : 0},
457 {dns_addr, dns_cnt * sizeof(*dns_addr)},
458 {search, search->len * 8},
459 {&adv_interval, adv_interval.len * 8}};
460 struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
462 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
463 dest.sin6_addr = *from;
465 odhcpd_send(router_event.uloop.fd,
466 &dest, iov, ARRAY_SIZE(iov), iface);
472 static void trigger_router_advert(struct uloop_timeout *event)
474 struct interface *iface = container_of(event, struct interface, timer_rs);
475 int msecs = send_router_advert(iface, NULL);
477 // Rearm timer if not shut down
479 uloop_timeout_set(event, msecs);
483 // Event handler for incoming ICMPv6 packets
484 static void handle_icmpv6(void *addr, void *data, size_t len,
485 struct interface *iface, _unused void *dest)
487 struct icmp6_hdr *hdr = data;
488 struct sockaddr_in6 *from = addr;
490 if (!router_icmpv6_valid(addr, data, len))
493 if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
494 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
495 send_router_advert(iface, &from->sin6_addr);
496 } else if (iface->ra == RELAYD_RELAY) { // Relay mode
497 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
498 forward_router_advertisement(data, len);
499 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
500 forward_router_solicitation(odhcpd_get_master_interface());
505 // Forward router solicitation
506 static void forward_router_solicitation(const struct interface *iface)
511 struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
512 struct iovec iov = {&rs, sizeof(rs)};
513 struct sockaddr_in6 all_routers =
514 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
516 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
517 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
521 // Handler for incoming router solicitations on slave interfaces
522 static void forward_router_advertisement(uint8_t *data, size_t len)
524 struct nd_router_advert *adv = (struct nd_router_advert *)data;
527 uint8_t *end = data + len;
528 uint8_t *mac_ptr = NULL;
529 struct in6_addr *dns_ptr = NULL;
530 size_t dns_count = 0;
532 struct icmpv6_opt *opt;
533 icmpv6_for_each_option(opt, &adv[1], end) {
534 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
535 // Store address of source MAC-address
537 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
538 // Check if we have to rewrite DNS
539 dns_ptr = (struct in6_addr*)&opt->data[6];
540 dns_count = (opt->len - 1) / 2;
544 syslog(LOG_NOTICE, "Got a RA");
546 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
547 adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
549 // Forward advertisement to all slave interfaces
550 struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
551 struct iovec iov = {data, len};
553 struct interface *iface;
554 list_for_each_entry(iface, &interfaces, head) {
555 if (iface->ra != RELAYD_RELAY || iface->master)
558 // Fixup source hardware address option
560 odhcpd_get_mac(iface, mac_ptr);
562 // If we have to rewrite DNS entries
563 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
564 const struct in6_addr *rewrite = iface->dns;
565 struct in6_addr addr;
566 size_t rewrite_cnt = iface->dns_cnt;
568 if (rewrite_cnt == 0) {
569 if (odhcpd_get_preferred_interface_address(iface->ifindex, &addr) < 1)
570 continue; // Unable to comply
576 // Copy over any other addresses
577 for (size_t i = 0; i < dns_count; ++i) {
578 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
579 dns_ptr[i] = rewrite[j];
583 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);