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 <arpa/inet.h>
24 #include <net/route.h>
30 static void forward_router_solicitation(const struct interface *iface);
31 static void forward_router_advertisement(uint8_t *data, size_t len);
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);
38 static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
40 static FILE *fp_route = NULL;
42 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
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));
53 // Let the kernel compute our checksums
55 setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
57 // This is required by RFC 4861
59 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
60 setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
62 // We need to know the source interface
64 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
65 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
69 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
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));
79 router_event.uloop.fd = sock;
80 odhcpd_register(&router_event);
82 if (!(fp_route = fopen("/proc/net/ipv6_route", "r")))
83 syslog(LOG_ERR, "Failed to open routing table: %s",
86 signal(SIGUSR1, sigusr1_refresh);
91 int setup_router_interface(struct interface *iface, bool enable)
93 if (!fp_route || router_event.uloop.fd < 0)
96 struct ipv6_mreq all_nodes = {ALL_IPV6_NODES, iface->ifindex};
97 struct ipv6_mreq all_routers = {ALL_IPV6_ROUTERS, iface->ifindex};
99 uloop_timeout_cancel(&iface->timer_rs);
100 iface->timer_rs.cb = NULL;
102 if (iface->ifindex <= 0)
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));
112 trigger_router_advert(&iface->timer_rs);
114 void *mreq = &all_routers;
116 if (iface->ra == RELAYD_RELAY && iface->master) {
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);
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));
132 // Signal handler to resend all RDs
133 static void sigusr1_refresh(_unused int signal)
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);
141 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
143 struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
144 struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
146 /* Hoplimit is already checked in odhcpd_receive_packets */
147 if (len < sizeof(*hdr) || hdr->icmp6_code)
150 switch (hdr->icmp6_type) {
151 case ND_ROUTER_ADVERT:
152 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
155 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
158 case ND_ROUTER_SOLICIT:
159 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
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)
172 // Check all options parsed successfully
177 // Detect whether a default route exists, also find the source prefixes
178 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
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};
187 while (fgets(line, sizeof(line), fp_route)) {
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]);
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;
212 return found_default;
215 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
218 uint32_t minival = iface->ra_mininterval;
221 *maxival = iface->ra_maxinterval;
223 if (*maxival > minvalid/3)
224 *maxival = minvalid/3;
226 if (*maxival > MaxRtrAdvInterval)
227 *maxival = MaxRtrAdvInterval;
228 else if (*maxival < 4)
231 if (minival < MinRtrAdvInterval)
232 minival = MinRtrAdvInterval;
233 else if (minival > (*maxival * 3)/4)
234 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
236 odhcpd_urandom(&msecs, sizeof(msecs));
237 msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
243 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
245 uint16_t lifetime = 3*maxival;
247 if (iface->ra_lifetime >= 0) {
248 lifetime = iface->ra_lifetime;
249 if (lifetime < maxival)
251 else if (lifetime > 9000)
269 // Router Advert server mode
270 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
272 time_t now = odhcpd_time();
273 int mtu = iface->ra_mtu;
274 int hlim = iface->ra_hoplimit;
277 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
283 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
286 struct nd_router_advert h;
287 struct icmpv6_opt lladdr;
288 struct nd_opt_mtu mtu;
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)},
296 adv.h.nd_ra_curhoplimit = hlim;
299 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
301 if (iface->ra_managed >= RA_MANAGED_MFLAG)
302 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
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;
309 adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
310 adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
312 odhcpd_get_mac(iface, adv.lladdr.data);
314 // If not currently shutting down
315 struct odhcpd_ipaddr *addrs = NULL;
317 uint32_t minvalid = UINT32_MAX;
318 bool default_route = false;
319 bool valid_prefix = false;
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);
327 ipcnt = iface->ia_addr_len;
329 // Check default route
330 if (iface->default_router) {
331 default_route = true;
333 if (iface->default_router > 1)
335 } else if (parse_routes(addrs, ipcnt))
336 default_route = true;
340 struct in6_addr dns_pref, *dns_addr = &dns_pref;
343 odhcpd_get_interface_dns_addr(iface, &dns_pref);
345 // Construct Prefix Information options
347 struct nd_opt_prefix_info *pfxs = NULL;
349 for (ssize_t i = 0; i < ipcnt; ++i) {
350 struct odhcpd_ipaddr *addr = &addrs[i];
351 uint32_t preferred = 0;
354 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
355 char namebuf[INET6_ADDRSTRLEN];
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);
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))
372 struct nd_opt_prefix_info *tmp;
374 tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
376 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
381 p = &pfxs[pfxs_cnt++];
382 memset(p, 0, sizeof(*p));
385 if (addr->preferred > (uint32_t)now) {
386 preferred = TIME_LEFT(addr->preferred, now);
388 if (iface->ra_useleasetime &&
389 preferred > iface->dhcpv4_leasetime)
390 preferred = iface->dhcpv4_leasetime;
393 valid = TIME_LEFT(addr->valid, now);
394 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
395 valid = iface->dhcpv4_leasetime;
397 if (minvalid > valid)
400 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
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);
419 // Calculate periodic transmit
421 int msecs = calc_adv_interval(iface, minvalid, &maxival);
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;
429 adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
432 adv.h.nd_ra_router_lifetime = 0;
434 syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
437 if (iface->dns_cnt > 0) {
438 dns_addr = iface->dns;
439 dns_cnt = iface->dns_cnt;
442 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
451 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
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;
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);
461 search_domain = search_buf;
467 search_padded = ((search_len + 7) & (~7)) + 8;
476 } *search = alloca(sizeof(*search) + search_padded);
478 search->type = ND_OPT_DNS_SEARCH;
479 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
482 memcpy(search->name, search_domain, search_len);
483 memset(&search->name[search_len], 0, search_padded - search_len);
486 size_t routes_cnt = 0;
494 } *tmp, *routes = NULL;
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;
508 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
510 syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
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;
534 search->lifetime = htonl(maxival*10);
535 dns.lifetime = search->lifetime;
537 struct icmpv6_opt adv_interval = {
538 .type = ND_OPT_RTR_ADV_INTERVAL,
540 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
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};
553 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
554 dest.sin6_addr = *from;
556 odhcpd_send(router_event.uloop.fd,
557 &dest, iov, ARRAY_SIZE(iov), iface);
566 static void trigger_router_advert(struct uloop_timeout *event)
568 struct interface *iface = container_of(event, struct interface, timer_rs);
569 int msecs = send_router_advert(iface, NULL);
571 // Rearm timer if not shut down
573 uloop_timeout_set(event, msecs);
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)
581 struct icmp6_hdr *hdr = data;
582 struct sockaddr_in6 *from = addr;
584 if (!router_icmpv6_valid(addr, data, len))
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());
599 // Forward router solicitation
600 static void forward_router_solicitation(const struct interface *iface)
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};
610 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
611 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
615 // Handler for incoming router solicitations on slave interfaces
616 static void forward_router_advertisement(uint8_t *data, size_t len)
618 struct nd_router_advert *adv = (struct nd_router_advert *)data;
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;
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
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;
638 syslog(LOG_NOTICE, "Got a RA");
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;
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};
647 struct interface *iface;
648 list_for_each_entry(iface, &interfaces, head) {
649 if (iface->ra != RELAYD_RELAY || iface->master)
652 // Fixup source hardware address option
654 odhcpd_get_mac(iface, mac_ptr);
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;
662 if (rewrite_cnt == 0) {
663 if (odhcpd_get_interface_dns_addr(iface, &addr))
664 continue; // Unable to comply
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];
677 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);