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 router_netevent_cb(unsigned long event, struct netevent_handler_info *info);
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, };
41 static FILE *fp_route = NULL;
44 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
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: %m");
55 // Let the kernel compute our checksums
57 setsockopt(sock, IPPROTO_RAW, IPV6_CHECKSUM, &val, sizeof(val));
59 // This is required by RFC 4861
61 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
62 setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &val, sizeof(val));
64 // We need to know the source interface
66 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
67 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &val, sizeof(val));
71 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
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));
81 router_event.uloop.fd = sock;
82 odhcpd_register(&router_event);
84 if (!(fp_route = fopen("/proc/net/ipv6_route", "r")))
85 syslog(LOG_ERR, "Failed to open routing table: %m");
87 netlink_add_netevent_handler(&router_netevent_handler);
93 int router_setup_interface(struct interface *iface, bool enable)
95 if (!fp_route || router_event.uloop.fd < 0)
98 struct ipv6_mreq all_nodes = {ALL_IPV6_NODES, iface->ifindex};
99 struct ipv6_mreq all_routers = {ALL_IPV6_ROUTERS, iface->ifindex};
101 uloop_timeout_cancel(&iface->timer_rs);
102 iface->timer_rs.cb = NULL;
104 if (iface->ifindex <= 0)
107 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
108 &all_nodes, sizeof(all_nodes));
109 setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
110 &all_routers, sizeof(all_routers));
114 trigger_router_advert(&iface->timer_rs);
116 void *mreq = &all_routers;
118 if (iface->ra == MODE_RELAY && iface->master) {
120 forward_router_solicitation(iface);
121 } else if (iface->ra == MODE_SERVER && !iface->master) {
122 iface->timer_rs.cb = trigger_router_advert;
123 uloop_timeout_set(&iface->timer_rs, 1000);
126 if (iface->ra == MODE_RELAY || (iface->ra == MODE_SERVER && !iface->master))
127 setsockopt(router_event.uloop.fd, IPPROTO_IPV6,
128 IPV6_ADD_MEMBERSHIP, mreq, sizeof(all_nodes));
134 static void router_netevent_cb(unsigned long event, struct netevent_handler_info *info)
136 struct interface *iface;
139 case NETEV_ROUTE6_ADD:
140 case NETEV_ROUTE6_DEL:
141 if (info->rt.dst_len)
144 list_for_each_entry(iface, &interfaces, head) {
145 if (iface->ra == MODE_SERVER && !iface->master)
146 uloop_timeout_set(&iface->timer_rs, 1000);
149 case NETEV_ADDR6LIST_CHANGE:
151 if (iface && iface->ra == MODE_SERVER && !iface->master)
152 uloop_timeout_set(&iface->timer_rs, 1000);
160 static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
162 struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
163 struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
165 /* Hoplimit is already checked in odhcpd_receive_packets */
166 if (len < sizeof(*hdr) || hdr->icmp6_code)
169 switch (hdr->icmp6_type) {
170 case ND_ROUTER_ADVERT:
171 if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
174 opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
177 case ND_ROUTER_SOLICIT:
178 opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
185 icmpv6_for_each_option(opt, opt, end)
186 if (opt->type == ND_OPT_SOURCE_LINKADDR &&
187 IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
188 hdr->icmp6_type == ND_ROUTER_SOLICIT)
191 // Check all options parsed successfully
196 // Detect whether a default route exists, also find the source prefixes
197 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
201 char line[512], ifname[16];
202 bool found_default = false;
203 struct odhcpd_ipaddr p = { .addr.in6 = IN6ADDR_ANY_INIT, .prefix = 0,
204 .dprefix = 0, .preferred = 0, .valid = 0};
206 while (fgets(line, sizeof(line), fp_route)) {
208 if (sscanf(line, "00000000000000000000000000000000 00 "
209 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname) &&
210 strcmp(ifname, "lo")) {
211 found_default = true;
212 } else if (sscanf(line, "%8" SCNx32 "%8" SCNx32 "%*8" SCNx32 "%*8" SCNx32 " %hhx %*s "
213 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32 " lo",
214 &p.addr.in6.s6_addr32[0], &p.addr.in6.s6_addr32[1], &p.prefix, &rflags) &&
215 p.prefix > 0 && (rflags & RTF_NONEXTHOP) && (rflags & RTF_REJECT)) {
216 // Find source prefixes by scanning through unreachable-routes
217 p.addr.in6.s6_addr32[0] = htonl(p.addr.in6.s6_addr32[0]);
218 p.addr.in6.s6_addr32[1] = htonl(p.addr.in6.s6_addr32[1]);
220 for (ssize_t i = 0; i < len; ++i) {
221 if (n[i].prefix <= 64 && n[i].prefix >= p.prefix &&
222 !odhcpd_bmemcmp(&p.addr.in6, &n[i].addr.in6, p.prefix)) {
223 n[i].dprefix = p.prefix;
231 return found_default;
234 static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
237 uint32_t minival = iface->ra_mininterval;
240 *maxival = iface->ra_maxinterval;
242 if (*maxival > minvalid/3)
243 *maxival = minvalid/3;
245 if (*maxival > MaxRtrAdvInterval)
246 *maxival = MaxRtrAdvInterval;
247 else if (*maxival < 4)
250 if (minival < MinRtrAdvInterval)
251 minival = MinRtrAdvInterval;
252 else if (minival > (*maxival * 3)/4)
253 minival = (*maxival >= 9 ? *maxival/3 : *maxival);
255 odhcpd_urandom(&msecs, sizeof(msecs));
256 msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
262 static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
264 uint16_t lifetime = 3*maxival;
266 if (iface->ra_lifetime >= 0) {
267 lifetime = iface->ra_lifetime;
268 if (lifetime < maxival)
270 else if (lifetime > 9000)
288 // Router Advert server mode
289 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
291 time_t now = odhcpd_time();
292 int mtu = iface->ra_mtu;
293 int hlim = iface->ra_hoplimit;
296 mtu = odhcpd_get_interface_config(iface->ifname, "mtu");
302 hlim = odhcpd_get_interface_config(iface->ifname, "hop_limit");
305 struct nd_router_advert h;
306 struct icmpv6_opt lladdr;
307 struct nd_opt_mtu mtu;
309 .h = {{.icmp6_type = ND_ROUTER_ADVERT, .icmp6_code = 0}, 0, 0},
310 .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
311 .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
315 adv.h.nd_ra_curhoplimit = hlim;
318 adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
320 if (iface->ra_managed >= RA_MANAGED_MFLAG)
321 adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
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;
329 adv.h.nd_ra_reachable = htonl(iface->ra_reachabletime);
330 adv.h.nd_ra_retransmit = htonl(iface->ra_retranstime);
332 odhcpd_get_mac(iface, adv.lladdr.data);
334 // If not currently shutting down
335 struct odhcpd_ipaddr *addrs = NULL;
337 uint32_t minvalid = UINT32_MAX;
338 bool default_route = false;
339 bool valid_prefix = false;
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);
347 ipcnt = iface->addr6_len;
349 // Check default route
350 if (iface->default_router) {
351 default_route = true;
353 if (iface->default_router > 1)
355 } else if (parse_routes(addrs, ipcnt))
356 default_route = true;
360 struct in6_addr dns_pref, *dns_addr = &dns_pref;
363 odhcpd_get_interface_dns_addr(iface, &dns_pref);
365 // Construct Prefix Information options
367 struct nd_opt_prefix_info *pfxs = NULL;
369 for (ssize_t i = 0; i < ipcnt; ++i) {
370 struct odhcpd_ipaddr *addr = &addrs[i];
371 uint32_t preferred = 0;
374 if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
375 char namebuf[INET6_ADDRSTRLEN];
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);
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
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))
397 struct nd_opt_prefix_info *tmp;
399 tmp = realloc(pfxs, sizeof(*pfxs) * (pfxs_cnt + 1));
401 syslog(LOG_ERR, "Realloc failed for RA prefix option on interface %s", iface->ifname);
406 p = &pfxs[pfxs_cnt++];
407 memset(p, 0, sizeof(*p));
410 if (addr->preferred > (uint32_t)now) {
411 preferred = TIME_LEFT(addr->preferred, now);
413 if (iface->ra_useleasetime &&
414 preferred > iface->dhcpv4_leasetime)
415 preferred = iface->dhcpv4_leasetime;
418 valid = TIME_LEFT(addr->valid, now);
419 if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
420 valid = iface->dhcpv4_leasetime;
422 if (minvalid > valid)
425 if (!IN6_IS_ADDR_ULA(&addr->addr.in6) || iface->default_router)
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);
444 // Calculate periodic transmit
446 int msecs = calc_adv_interval(iface, minvalid, &maxival);
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;
454 adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
457 adv.h.nd_ra_router_lifetime = 0;
459 syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
462 if (iface->dns_cnt > 0) {
463 dns_addr = iface->dns;
464 dns_cnt = iface->dns_cnt;
467 if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
476 } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
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;
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);
486 search_domain = search_buf;
492 search_padded = ((search_len + 7) & (~7)) + 8;
501 } *search = alloca(sizeof(*search) + search_padded);
503 search->type = ND_OPT_DNS_SEARCH;
504 search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
507 memcpy(search->name, search_domain, search_len);
508 memset(&search->name[search_len], 0, search_padded - search_len);
511 size_t routes_cnt = 0;
519 } *tmp, *routes = NULL;
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 continue; // Address not suitable
526 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;
533 tmp = realloc(routes, sizeof(*routes) * (routes_cnt + 1));
535 syslog(LOG_ERR, "Realloc failed for RA route option on interface %s", iface->ifname);
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;
559 search->lifetime = htonl(maxival*10);
560 dns.lifetime = search->lifetime;
562 struct icmpv6_opt adv_interval = {
563 .type = ND_OPT_RTR_ADV_INTERVAL,
565 .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
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};
578 if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
579 dest.sin6_addr = *from;
581 odhcpd_send(router_event.uloop.fd,
582 &dest, iov, ARRAY_SIZE(iov), iface);
591 static void trigger_router_advert(struct uloop_timeout *event)
593 struct interface *iface = container_of(event, struct interface, timer_rs);
594 int msecs = send_router_advert(iface, NULL);
596 // Rearm timer if not shut down
598 uloop_timeout_set(event, msecs);
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)
606 struct icmp6_hdr *hdr = data;
607 struct sockaddr_in6 *from = addr;
609 if (!router_icmpv6_valid(addr, data, len))
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());
624 // Forward router solicitation
625 static void forward_router_solicitation(const struct interface *iface)
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};
635 syslog(LOG_NOTICE, "Sending RS to %s", iface->ifname);
636 odhcpd_send(router_event.uloop.fd, &all_routers, &iov, 1, iface);
640 // Handler for incoming router solicitations on slave interfaces
641 static void forward_router_advertisement(uint8_t *data, size_t len)
643 struct nd_router_advert *adv = (struct nd_router_advert *)data;
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;
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
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;
663 syslog(LOG_NOTICE, "Got a RA");
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;
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};
672 struct interface *iface;
673 list_for_each_entry(iface, &interfaces, head) {
674 if (iface->ra != MODE_RELAY || iface->master)
677 // Fixup source hardware address option
679 odhcpd_get_mac(iface, mac_ptr);
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;
687 if (rewrite_cnt == 0) {
688 if (odhcpd_get_interface_dns_addr(iface, &addr))
689 continue; // Unable to comply
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];
702 odhcpd_send(router_event.uloop.fd, &all_nodes, &iov, 1, iface);