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;
209 // Router Advert server mode
210 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
212 int mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
213 int hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
219 struct nd_router_advert h;
220 struct icmpv6_opt lladdr;
221 struct nd_opt_mtu mtu;
222 struct nd_opt_prefix_info prefix[RELAYD_MAX_PREFIXES];
224 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
225 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
226 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
230 adv.h.nd_ra_curhoplimit = hlim;
233 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
235 if (iface->managed >= RELAYD_MANAGED_MFLAG)
236 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
238 if (iface->route_preference < 0)
239 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_LOW;
240 else if (iface->route_preference > 0)
241 adv.h.nd_ra_flags_reserved |= ND_RA_PREF_HIGH;
242 odhcpd_get_mac(iface, adv.lladdr.data);
244 // If not currently shutting down
245 struct odhcpd_ipaddr addrs[RELAYD_MAX_PREFIXES];
247 uint64_t minvalid = UINT64_MAX;
248 uint64_t maxvalid = 0;
251 if (iface->timer_rs.cb) {
252 ipcnt = odhcpd_get_interface_addresses(iface->ifindex,
253 addrs, ARRAY_SIZE(addrs));
255 // Check default route
256 if (iface->default_router > 1)
257 adv.h.nd_ra_router_lifetime = htons(iface->default_router);
258 if (parse_routes(addrs, ipcnt))
259 adv.h.nd_ra_router_lifetime = htons(1);
262 // Construct Prefix Information options
265 struct in6_addr dns_pref = IN6ADDR_ANY_INIT, *dns_addr = &dns_pref;
266 uint32_t dns_time = 0;
269 for (ssize_t i = 0; i < ipcnt; ++i) {
270 struct odhcpd_ipaddr *addr = &addrs[i];
271 if (addr->prefix > 96)
272 continue; // Address not suitable
274 if (addr->preferred > MaxValidTime)
275 addr->preferred = MaxValidTime;
277 if (addr->valid > MaxValidTime)
278 addr->valid = MaxValidTime;
280 struct nd_opt_prefix_info *p = NULL;
281 for (size_t i = 0; i < cnt; ++i) {
282 if (addr->prefix == adv.prefix[i].nd_opt_pi_prefix_len &&
283 !odhcpd_bmemcmp(&adv.prefix[i].nd_opt_pi_prefix,
284 &addr->addr, addr->prefix))
289 if (cnt >= ARRAY_SIZE(adv.prefix))
292 p = &adv.prefix[cnt++];
295 if (addr->preferred > 0 &&
296 minvalid > 1000ULL * addr->valid)
297 minvalid = 1000ULL * addr->valid;
299 if (maxvalid < 1000ULL * addr->valid)
300 maxvalid = 1000ULL * addr->valid;
302 if (((addr->addr.s6_addr[0] & 0xfe) != 0xfc || iface->default_router)
303 && ntohs(adv.h.nd_ra_router_lifetime) < addr->valid)
304 adv.h.nd_ra_router_lifetime = htons(addr->valid);
306 odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
307 (iface->ra_advrouter) ? 128 : addr->prefix);
308 p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
309 p->nd_opt_pi_len = 4;
310 p->nd_opt_pi_prefix_len = (addr->prefix < 64) ? 64 : addr->prefix;
311 p->nd_opt_pi_flags_reserved = 0;
312 if (!iface->ra_not_onlink)
313 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_ONLINK;
314 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && addr->prefix <= 64)
315 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
316 if (iface->ra_advrouter)
317 p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
318 p->nd_opt_pi_valid_time = htonl(addr->valid);
319 p->nd_opt_pi_preferred_time = htonl(addr->preferred);
321 if (addr->preferred > dns_time) {
322 dns_time = addr->preferred;
323 dns_pref = addr->addr;
327 if (!iface->default_router && ntohs(adv.h.nd_ra_router_lifetime) == 1) {
328 syslog(LOG_WARNING, "A default route is present but there is no public prefix "
329 "on %s thus we don't announce a default route!", iface->ifname);
330 adv.h.nd_ra_router_lifetime = 0;
334 if (iface->dns_cnt > 0) {
335 dns_addr = iface->dns;
336 dns_cnt = iface->dns_cnt;
340 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
349 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
353 // DNS Search options
354 uint8_t search_buf[256], *search_domain = iface->search;
355 size_t search_len = iface->search_len, search_padded = 0;
357 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
358 int len = dn_comp(_res.dnsrch[0], search_buf,
359 sizeof(search_buf), NULL, NULL);
361 search_domain = search_buf;
367 search_padded = ((search_len + 7) & (~7)) + 8;
376 } *search = alloca(sizeof(*search) + search_padded);
378 search->type = ND_OPT_DNS_SEARCH;
379 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
382 memcpy(search->name, search_domain, search_len);
383 memset(&search->name[search_len], 0, search_padded - search_len);
386 size_t routes_cnt = 0;
394 } routes[RELAYD_MAX_PREFIXES];
396 for (ssize_t i = 0; i < ipcnt; ++i) {
397 struct odhcpd_ipaddr *addr = &addrs[i];
398 if (addr->dprefix > 64 || addr->dprefix == 0 ||
399 (addr->dprefix == 64 && addr->prefix == 64)) {
400 continue; // Address not suitable
401 } else if (addr->dprefix > 32) {
402 addr->addr.s6_addr32[1] &= htonl(~((1U << (64 - addr->dprefix)) - 1));
403 } else if (addr->dprefix <= 32) {
404 addr->addr.s6_addr32[0] &= htonl(~((1U << (32 - addr->dprefix)) - 1));
405 addr->addr.s6_addr32[1] = 0;
408 routes[routes_cnt].type = ND_OPT_ROUTE_INFO;
409 routes[routes_cnt].len = sizeof(*routes) / 8;
410 routes[routes_cnt].prefix = addr->dprefix;
411 routes[routes_cnt].flags = 0;
412 if (iface->route_preference < 0)
413 routes[routes_cnt].flags |= ND_RA_PREF_LOW;
414 else if (iface->route_preference > 0)
415 routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
416 routes[routes_cnt].lifetime = htonl(addr->valid);
417 routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
418 routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
419 routes[routes_cnt].addr[2] = 0;
420 routes[routes_cnt].addr[3] = 0;
425 // Calculate periodic transmit
427 uint32_t maxival = iface->ra_maxinterval * 1000;
430 if (maxival < 4000 || maxival > MaxRtrAdvInterval * 1000)
431 maxival = MaxRtrAdvInterval * 1000;
433 if (maxival > minvalid / 3) {
434 maxival = minvalid / 3;
440 minival = (maxival * 3) / 4;
442 search->lifetime = htonl(maxvalid / 1000);
445 dns.lifetime = search->lifetime;
447 odhcpd_urandom(&msecs, sizeof(msecs));
448 msecs = (labs(msecs) % (maxival - minival)) + minival;
450 struct icmpv6_opt adv_interval = {
451 .type = ND_OPT_RTR_ADV_INTERVAL,
453 .data = {0, 0, maxival >> 24, maxival >> 16, maxival >> 8, maxival}
456 struct iovec iov[RA_IOV_LEN] = {
457 {&adv, (uint8_t*)&adv.prefix[cnt] - (uint8_t*)&adv},
458 {&routes, routes_cnt * sizeof(*routes)},
459 {&dns, (dns_cnt) ? sizeof(dns) : 0},
460 {dns_addr, dns_cnt * sizeof(*dns_addr)},
461 {search, search->len * 8},
462 {&adv_interval, adv_interval.len * 8}};
463 struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
465 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
466 dest.sin6_addr = *from;
468 odhcpd_send(router_event.uloop.fd,
469 &dest, iov, ARRAY_SIZE(iov), iface);
475 static void trigger_router_advert(struct uloop_timeout *event)
477 struct interface *iface = container_of(event, struct interface, timer_rs);
478 int msecs = send_router_advert(iface, NULL);
480 // Rearm timer if not shut down
482 uloop_timeout_set(event, msecs);
486 // Event handler for incoming ICMPv6 packets
487 static void handle_icmpv6(void *addr, void *data, size_t len,
488 struct interface *iface, _unused void *dest)
490 struct icmp6_hdr *hdr = data;
491 struct sockaddr_in6 *from = addr;
493 if (!router_icmpv6_valid(addr, data, len))
496 if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
497 if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
498 send_router_advert(iface, &from->sin6_addr);
499 } else if (iface->ra == RELAYD_RELAY) { // Relay mode
500 if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
501 forward_router_advertisement(data, len);
502 else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
503 forward_router_solicitation(odhcpd_get_master_interface());
508 // Forward router solicitation
509 static void forward_router_solicitation(const struct interface *iface)
514 struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
515 struct iovec iov = {&rs, sizeof(rs)};
516 struct sockaddr_in6 all_routers =
517 {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, iface->ifindex};
519 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
520 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
524 // Handler for incoming router solicitations on slave interfaces
525 static void forward_router_advertisement(uint8_t *data, size_t len)
527 struct nd_router_advert *adv = (struct nd_router_advert *)data;
530 uint8_t *end = data + len;
531 uint8_t *mac_ptr = NULL;
532 struct in6_addr *dns_ptr = NULL;
533 size_t dns_count = 0;
535 struct icmpv6_opt *opt;
536 icmpv6_for_each_option(opt, &adv[1], end) {
537 if (opt->type == ND_OPT_SOURCE_LINKADDR) {
538 // Store address of source MAC-address
540 } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 1) {
541 // Check if we have to rewrite DNS
542 dns_ptr = (struct in6_addr*)&opt->data[6];
543 dns_count = (opt->len - 1) / 2;
547 syslog(LOG_NOTICE, "Got a RA");
549 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
550 adv->nd_ra_flags_reserved |= ND_RA_FLAG_PROXY;
552 // Forward advertisement to all slave interfaces
553 struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
554 struct iovec iov = {data, len};
556 struct interface *iface;
557 list_for_each_entry(iface, &interfaces, head) {
558 if (iface->ra != RELAYD_RELAY || iface->master)
561 // Fixup source hardware address option
563 odhcpd_get_mac(iface, mac_ptr);
565 // If we have to rewrite DNS entries
566 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
567 const struct in6_addr *rewrite = iface->dns;
568 struct in6_addr addr;
569 size_t rewrite_cnt = iface->dns_cnt;
571 if (rewrite_cnt == 0) {
572 if (odhcpd_get_preferred_interface_address(iface->ifindex, &addr) < 1)
573 continue; // Unable to comply
579 // Copy over any other addresses
580 for (size_t i = 0; i < dns_count; ++i) {
581 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
582 dns_ptr[i] = rewrite[j];
586 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);