2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2018 Hans Dedecker <dedeckeh@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
21 #include <sys/timerfd.h>
22 #include <arpa/inet.h>
24 #include <libubox/utils.h>
30 static void relay_client_request(struct sockaddr_in6 *source,
31 const void *data, size_t len, struct interface *iface);
32 static void relay_server_response(uint8_t *data, size_t len);
34 static void handle_dhcpv6(void *addr, void *data, size_t len,
35 struct interface *iface, void *dest);
36 static void handle_client_request(void *addr, void *data, size_t len,
37 struct interface *iface, void *dest_addr);
40 /* Create socket and register events */
43 return dhcpv6_ia_init();
46 int dhcpv6_setup_interface(struct interface *iface, bool enable)
50 if (iface->dhcpv6_event.uloop.fd > 0) {
51 uloop_fd_delete(&iface->dhcpv6_event.uloop);
52 close(iface->dhcpv6_event.uloop.fd);
53 iface->dhcpv6_event.uloop.fd = -1;
56 /* Configure multicast settings */
57 if (enable && iface->dhcpv6) {
58 struct sockaddr_in6 bind_addr = {AF_INET6, htons(DHCPV6_SERVER_PORT),
59 0, IN6ADDR_ANY_INIT, 0};
60 struct ipv6_mreq mreq;
63 iface->dhcpv6_event.uloop.fd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
64 if (iface->dhcpv6_event.uloop.fd < 0) {
65 syslog(LOG_ERR, "socket(AF_INET6): %m");
70 /* Basic IPv6 configuration */
71 if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
72 iface->ifname, strlen(iface->ifname)) < 0) {
73 syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
78 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_V6ONLY,
79 &val, sizeof(val)) < 0) {
80 syslog(LOG_ERR, "setsockopt(IPV6_V6ONLY): %m");
85 if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
86 &val, sizeof(val)) < 0) {
87 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
92 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
93 &val, sizeof(val)) < 0) {
94 syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m");
99 val = DHCPV6_HOP_COUNT_LIMIT;
100 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
101 &val, sizeof(val)) < 0) {
102 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m");
108 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
109 &val, sizeof(val)) < 0) {
110 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m");
115 if (bind(iface->dhcpv6_event.uloop.fd, (struct sockaddr*)&bind_addr,
116 sizeof(bind_addr)) < 0) {
117 syslog(LOG_ERR, "bind(): %m");
122 memset(&mreq, 0, sizeof(mreq));
123 inet_pton(AF_INET6, ALL_DHCPV6_RELAYS, &mreq.ipv6mr_multiaddr);
124 mreq.ipv6mr_interface = iface->ifindex;
126 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
127 &mreq, sizeof(mreq)) < 0) {
128 syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
133 if (iface->dhcpv6 == MODE_SERVER) {
134 memset(&mreq, 0, sizeof(mreq));
135 inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &mreq.ipv6mr_multiaddr);
136 mreq.ipv6mr_interface = iface->ifindex;
138 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
139 &mreq, sizeof(mreq)) < 0) {
140 syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
146 iface->dhcpv6_event.handle_dgram = handle_dhcpv6;
147 odhcpd_register(&iface->dhcpv6_event);
150 ret = dhcpv6_ia_setup_interface(iface, enable);
153 if (ret < 0 && iface->dhcpv6_event.uloop.fd > 0) {
154 close(iface->dhcpv6_event.uloop.fd);
155 iface->dhcpv6_event.uloop.fd = -1;
165 #define IOV_STAT IOV_MAXRT
172 #define IOV_REFRESH IOV_PDBUF
179 static void handle_nested_message(uint8_t *data, size_t len,
180 struct dhcpv6_client_header **c_hdr, uint8_t **opts,
181 uint8_t **end, struct iovec iov[IOV_TOTAL])
183 struct dhcpv6_relay_header *r_hdr = (struct dhcpv6_relay_header *)data;
184 uint16_t otype, olen;
187 if (iov[IOV_NESTED].iov_base == NULL) {
188 iov[IOV_NESTED].iov_base = data;
189 iov[IOV_NESTED].iov_len = len;
192 if (len < sizeof(struct dhcpv6_client_header))
195 if (r_hdr->msg_type != DHCPV6_MSG_RELAY_FORW) {
196 iov[IOV_NESTED].iov_len = data - (uint8_t *)iov[IOV_NESTED].iov_base;
197 *c_hdr = (void *)data;
198 *opts = (uint8_t *)&(*c_hdr)[1];
203 dhcpv6_for_each_option(r_hdr->options, data + len, otype, olen, odata) {
204 if (otype == DHCPV6_OPT_RELAY_MSG) {
205 iov[IOV_RELAY_MSG].iov_base = odata + olen;
206 iov[IOV_RELAY_MSG].iov_len = (((uint8_t *)iov[IOV_NESTED].iov_base) +
207 iov[IOV_NESTED].iov_len) - (odata + olen);
208 handle_nested_message(odata, olen, c_hdr, opts, end, iov);
215 static void update_nested_message(uint8_t *data, size_t len, ssize_t pdiff)
217 struct dhcpv6_relay_header *hdr = (struct dhcpv6_relay_header*)data;
218 if (hdr->msg_type != DHCPV6_MSG_RELAY_FORW)
221 hdr->msg_type = DHCPV6_MSG_RELAY_REPL;
223 uint16_t otype, olen;
225 dhcpv6_for_each_option(hdr->options, data + len, otype, olen, odata) {
226 if (otype == DHCPV6_OPT_RELAY_MSG) {
228 odata[-2] = (olen >> 8) & 0xff;
229 odata[-1] = olen & 0xff;
230 update_nested_message(odata, olen - pdiff, pdiff);
236 /* Simple DHCPv6-server for information requests */
237 static void handle_client_request(void *addr, void *data, size_t len,
238 struct interface *iface, void *dest_addr)
240 struct dhcpv6_client_header *hdr = data;
241 uint8_t *opts = (uint8_t *)&hdr[1], *opts_end = (uint8_t *)data + len;
242 bool o_rapid_commit = false;
244 if (len < sizeof(*hdr))
247 syslog(LOG_NOTICE, "Got DHCPv6 request on %s", iface->name);
249 /* Construct reply message */
250 struct __attribute__((packed)) {
253 uint16_t serverid_type;
254 uint16_t serverid_length;
256 uint16_t hardware_type;
258 uint16_t clientid_type;
259 uint16_t clientid_length;
260 uint8_t clientid_buf[130];
262 .msg_type = DHCPV6_MSG_REPLY,
263 .serverid_type = htons(DHCPV6_OPT_SERVERID),
264 .serverid_length = htons(10),
265 .duid_type = htons(3),
266 .hardware_type = htons(1),
267 .clientid_type = htons(DHCPV6_OPT_CLIENTID),
270 odhcpd_get_mac(iface, dest.mac);
272 struct __attribute__((packed)) {
276 } maxrt = {htons(DHCPV6_OPT_SOL_MAX_RT), htons(sizeof(maxrt) - 4),
279 struct __attribute__((packed)) {
282 } rapid_commit = {htons(DHCPV6_OPT_RAPID_COMMIT), 0};
284 struct __attribute__((packed)) {
288 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
289 htons(DHCPV6_STATUS_USEMULTICAST)};
291 struct __attribute__((packed)) {
295 } refresh = {htons(DHCPV6_OPT_INFO_REFRESH), htons(sizeof(uint32_t)),
298 struct in6_addr dns_addr, *dns_addr_ptr = iface->dns;
299 size_t dns_cnt = iface->dns_cnt;
301 if ((dns_cnt == 0) &&
302 !odhcpd_get_interface_dns_addr(iface, &dns_addr)) {
303 dns_addr_ptr = &dns_addr;
310 } dns = {htons(DHCPV6_OPT_DNS_SERVERS), htons(dns_cnt * sizeof(*dns_addr_ptr))};
314 /* DNS Search options */
315 uint8_t search_buf[256], *search_domain = iface->search;
316 size_t search_len = iface->search_len;
318 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
319 int len = dn_comp(_res.dnsrch[0], search_buf,
320 sizeof(search_buf), NULL, NULL);
322 search_domain = search_buf;
330 } search = {htons(DHCPV6_OPT_DNS_DOMAIN), htons(search_len)};
333 struct dhcpv6_cer_id cerid = {
335 .type = htons(EXT_CER_ID),
338 .addr = iface->dhcpv6_pd_cer,
343 struct iovec iov[IOV_TOTAL] = {
344 [IOV_NESTED] = {NULL, 0},
345 [IOV_DEST] = {&dest, (uint8_t*)&dest.clientid_type - (uint8_t*)&dest},
346 [IOV_MAXRT] = {&maxrt, sizeof(maxrt)},
347 [IOV_RAPID_COMMIT] = {&rapid_commit, 0},
348 [IOV_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
349 [IOV_DNS_ADDR] = {dns_addr_ptr, dns_cnt * sizeof(*dns_addr_ptr)},
350 [IOV_SEARCH] = {&search, (search_len) ? sizeof(search) : 0},
351 [IOV_SEARCH_DOMAIN] = {search_domain, search_len},
352 [IOV_PDBUF] = {pdbuf, 0},
353 [IOV_CERID] = {&cerid, 0},
354 [IOV_DHCPV6_RAW] = {iface->dhcpv6_raw, iface->dhcpv6_raw_len},
355 [IOV_RELAY_MSG] = {NULL, 0}
358 if (hdr->msg_type == DHCPV6_MSG_RELAY_FORW)
359 handle_nested_message(data, len, &hdr, &opts, &opts_end, iov);
361 if (hdr->msg_type == DHCPV6_MSG_ADVERTISE || hdr->msg_type == DHCPV6_MSG_REPLY ||
362 hdr->msg_type == DHCPV6_MSG_RELAY_REPL)
365 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
366 (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_CONFIRM ||
367 hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST))
370 memcpy(dest.tr_id, hdr->transaction_id, sizeof(dest.tr_id));
372 /* Go through options and find what we need */
373 uint16_t otype, olen;
375 dhcpv6_for_each_option(opts, opts_end, otype, olen, odata) {
376 if (otype == DHCPV6_OPT_CLIENTID && olen <= 130) {
377 dest.clientid_length = htons(olen);
378 memcpy(dest.clientid_buf, odata, olen);
379 iov[IOV_DEST].iov_len += 4 + olen;
380 } else if (otype == DHCPV6_OPT_SERVERID) {
381 if (olen != ntohs(dest.serverid_length) ||
382 memcmp(odata, &dest.duid_type, olen))
383 return; /* Not for us */
384 } else if (iface->filter_class && otype == DHCPV6_OPT_USER_CLASS) {
385 uint8_t *c = odata, *cend = &odata[olen];
386 for (; &c[2] <= cend && &c[2 + (c[0] << 8) + c[1]] <= cend; c = &c[2 + (c[0] << 8) + c[1]]) {
387 size_t elen = strlen(iface->filter_class);
388 if (((((size_t)c[0]) << 8) | c[1]) == elen && !memcmp(&c[2], iface->filter_class, elen))
389 return; /* Ignore from homenet */
391 } else if (otype == DHCPV6_OPT_IA_PD) {
393 iov[IOV_CERID].iov_len = sizeof(cerid);
395 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)) {
396 struct odhcpd_ipaddr *addrs;
397 ssize_t len = netlink_get_interface_addrs(0, true, &addrs);
399 for (ssize_t i = 0; i < len; ++i)
400 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)
401 || memcmp(&addrs[i].addr, &cerid.addr, sizeof(cerid.addr)) < 0)
402 cerid.addr = addrs[i].addr.in6;
407 } else if (otype == DHCPV6_OPT_RAPID_COMMIT && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
408 iov[IOV_RAPID_COMMIT].iov_len = sizeof(rapid_commit);
409 o_rapid_commit = true;
413 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
414 (hdr->msg_type == DHCPV6_MSG_REQUEST || hdr->msg_type == DHCPV6_MSG_RENEW ||
415 hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE)) {
416 iov[IOV_STAT].iov_base = &stat;
417 iov[IOV_STAT].iov_len = sizeof(stat);
419 for (ssize_t i = IOV_STAT + 1; i < IOV_TOTAL; ++i)
422 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
426 if (hdr->msg_type == DHCPV6_MSG_SOLICIT && !o_rapid_commit) {
427 dest.msg_type = DHCPV6_MSG_ADVERTISE;
428 } else if (hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST) {
429 iov[IOV_REFRESH].iov_base = &refresh;
430 iov[IOV_REFRESH].iov_len = sizeof(refresh);
432 /* Return inf max rt option in reply to information request */
433 maxrt.type = htons(DHCPV6_OPT_INF_MAX_RT);
436 if (hdr->msg_type != DHCPV6_MSG_INFORMATION_REQUEST) {
437 ssize_t ialen = dhcpv6_ia_handle_IAs(pdbuf, sizeof(pdbuf), iface, addr, (const void *)hdr, opts_end);
439 iov[IOV_PDBUF].iov_len = ialen;
441 (ialen == 0 && (hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_CONFIRM)))
445 if (iov[IOV_NESTED].iov_len > 0) /* Update length */
446 update_nested_message(data, len, iov[IOV_DEST].iov_len + iov[IOV_MAXRT].iov_len +
447 iov[IOV_RAPID_COMMIT].iov_len + iov[IOV_DNS].iov_len +
448 iov[IOV_DNS_ADDR].iov_len + iov[IOV_SEARCH].iov_len +
449 iov[IOV_SEARCH_DOMAIN].iov_len + iov[IOV_PDBUF].iov_len +
450 iov[IOV_CERID].iov_len + iov[IOV_DHCPV6_RAW].iov_len -
451 (4 + opts_end - opts));
453 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
457 /* Central DHCPv6-relay handler */
458 static void handle_dhcpv6(void *addr, void *data, size_t len,
459 struct interface *iface, void *dest_addr)
461 if (iface->dhcpv6 == MODE_SERVER) {
462 handle_client_request(addr, data, len, iface, dest_addr);
463 } else if (iface->dhcpv6 == MODE_RELAY) {
465 relay_server_response(data, len);
467 relay_client_request(addr, data, len, iface);
472 /* Relay server response (regular relay server handling) */
473 static void relay_server_response(uint8_t *data, size_t len)
475 /* Information we need to gather */
476 uint8_t *payload_data = NULL;
477 size_t payload_len = 0;
478 int32_t ifaceidx = 0;
479 struct sockaddr_in6 target = {AF_INET6, htons(DHCPV6_CLIENT_PORT),
480 0, IN6ADDR_ANY_INIT, 0};
482 syslog(LOG_NOTICE, "Got a DHCPv6-reply");
485 uint8_t *odata, *end = data + len;
487 /* Relay DHCPv6 reply from server to client */
488 struct dhcpv6_relay_header *h = (void*)data;
489 if (len < sizeof(*h) || h->msg_type != DHCPV6_MSG_RELAY_REPL)
492 memcpy(&target.sin6_addr, &h->peer_address,
493 sizeof(struct in6_addr));
495 /* Go through options and find what we need */
496 dhcpv6_for_each_option(h->options, end, otype, olen, odata) {
497 if (otype == DHCPV6_OPT_INTERFACE_ID
498 && olen == sizeof(ifaceidx)) {
499 memcpy(&ifaceidx, odata, sizeof(ifaceidx));
500 } else if (otype == DHCPV6_OPT_RELAY_MSG) {
501 payload_data = odata;
506 /* Invalid interface-id or basic payload */
507 struct interface *iface = odhcpd_get_interface_by_index(ifaceidx);
508 if (!iface || iface->master || !payload_data || payload_len < 4)
511 bool is_authenticated = false;
512 struct in6_addr *dns_ptr = NULL;
513 size_t dns_count = 0;
515 /* If the payload is relay-reply we have to send to the server port */
516 if (payload_data[0] == DHCPV6_MSG_RELAY_REPL) {
517 target.sin6_port = htons(DHCPV6_SERVER_PORT);
518 } else { /* Go through the payload data */
519 struct dhcpv6_client_header *h = (void*)payload_data;
520 end = payload_data + payload_len;
522 dhcpv6_for_each_option(&h[1], end, otype, olen, odata) {
523 if (otype == DHCPV6_OPT_DNS_SERVERS && olen >= 16) {
524 dns_ptr = (struct in6_addr*)odata;
525 dns_count = olen / 16;
526 } else if (otype == DHCPV6_OPT_AUTH) {
527 is_authenticated = true;
532 /* Rewrite DNS servers if requested */
533 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
534 if (is_authenticated)
535 return; /* Impossible to rewrite */
537 const struct in6_addr *rewrite = iface->dns;
538 struct in6_addr addr;
539 size_t rewrite_cnt = iface->dns_cnt;
541 if (rewrite_cnt == 0) {
542 if (odhcpd_get_interface_dns_addr(iface, &addr))
543 return; // Unable to get interface address
549 /* Copy over any other addresses */
550 for (size_t i = 0; i < dns_count; ++i) {
551 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
552 memcpy(&dns_ptr[i], &rewrite[j], sizeof(*rewrite));
556 struct iovec iov = {payload_data, payload_len};
557 odhcpd_send(iface->dhcpv6_event.uloop.fd, &target, &iov, 1, iface);
560 static struct odhcpd_ipaddr *relay_link_address(struct interface *iface)
562 struct odhcpd_ipaddr *addr = NULL;
563 time_t now = odhcpd_time();
565 for (size_t i = 0; i < iface->addr6_len; i++) {
566 if (iface->addr6[i].valid <= (uint32_t)now)
569 if (iface->addr6[i].preferred > (uint32_t)now) {
570 addr = &iface->addr6[i];
574 if (!addr || (iface->addr6[i].valid > addr->valid))
575 addr = &iface->addr6[i];
581 /* Relay client request (regular DHCPv6-relay) */
582 static void relay_client_request(struct sockaddr_in6 *source,
583 const void *data, size_t len, struct interface *iface)
585 struct interface *master = odhcpd_get_master_interface();
586 const struct dhcpv6_relay_header *h = data;
587 struct sockaddr_in6 s;
589 if (!master || master->dhcpv6 != MODE_RELAY ||
590 h->msg_type == DHCPV6_MSG_RELAY_REPL ||
591 h->msg_type == DHCPV6_MSG_RECONFIGURE ||
592 h->msg_type == DHCPV6_MSG_REPLY ||
593 h->msg_type == DHCPV6_MSG_ADVERTISE)
594 return; /* Invalid message types for client */
596 syslog(LOG_NOTICE, "Got a DHCPv6-request");
598 /* Construct our forwarding envelope */
599 struct dhcpv6_relay_forward_envelope hdr = {
600 .msg_type = DHCPV6_MSG_RELAY_FORW,
602 .interface_id_type = htons(DHCPV6_OPT_INTERFACE_ID),
603 .interface_id_len = htons(sizeof(uint32_t)),
604 .relay_message_type = htons(DHCPV6_OPT_RELAY_MSG),
605 .relay_message_len = htons(len),
608 if (h->msg_type == DHCPV6_MSG_RELAY_FORW) { /* handle relay-forward */
609 if (h->hop_count >= DHCPV6_HOP_COUNT_LIMIT)
610 return; // Invalid hop count
612 hdr.hop_count = h->hop_count + 1;
615 /* use memcpy here as the destination fields are unaligned */
616 uint32_t ifindex = iface->ifindex;
617 memcpy(&hdr.peer_address, &source->sin6_addr, sizeof(struct in6_addr));
618 memcpy(&hdr.interface_id_data, &ifindex, sizeof(ifindex));
620 /* Detect public IP of slave interface to use as link-address */
621 struct odhcpd_ipaddr *ip = relay_link_address(iface);
623 /* No suitable address! Is the slave not configured yet?
624 * Detect public IP of master interface and use it instead
625 * This is WRONG and probably violates the RFC. However
626 * otherwise we have a hen and egg problem because the
627 * slave-interface cannot be auto-configured. */
628 ip = relay_link_address(master);
630 return; /* Could not obtain a suitable address */
633 memcpy(&hdr.link_address, &ip->addr.in6, sizeof(hdr.link_address));
635 memset(&s, 0, sizeof(s));
636 s.sin6_family = AF_INET6;
637 s.sin6_port = htons(DHCPV6_SERVER_PORT);
638 inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &s.sin6_addr);
640 struct iovec iov[2] = {{&hdr, sizeof(hdr)}, {(void*)data, len}};
641 odhcpd_send(master->dhcpv6_event.uloop.fd, &s, iov, 2, master);