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.
20 #include <sys/timerfd.h>
26 static void relay_client_request(struct sockaddr_in6 *source,
27 const void *data, size_t len, struct interface *iface);
28 static void relay_server_response(uint8_t *data, size_t len);
30 static void handle_dhcpv6(void *addr, void *data, size_t len,
31 struct interface *iface, void *dest);
32 static void handle_client_request(void *addr, void *data, size_t len,
33 struct interface *iface, void *dest_addr);
37 // Create socket and register events
45 int setup_dhcpv6_interface(struct interface *iface, bool enable)
47 if (iface->dhcpv6_event.uloop.fd > 0) {
48 uloop_fd_delete(&iface->dhcpv6_event.uloop);
49 close(iface->dhcpv6_event.uloop.fd);
50 iface->dhcpv6_event.uloop.fd = -1;
53 // Configure multicast settings
54 if (enable && iface->dhcpv6 && !iface->master) {
55 int sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
57 syslog(LOG_ERR, "Failed to create DHCPv6 server socket: %s",
62 // Basic IPv6 configuration
63 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, iface->ifname, strlen(iface->ifname));
66 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
67 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
68 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
70 val = DHCPV6_HOP_COUNT_LIMIT;
71 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &val, sizeof(val));
74 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
76 struct sockaddr_in6 bind_addr = {AF_INET6, htons(DHCPV6_SERVER_PORT),
77 0, IN6ADDR_ANY_INIT, 0};
79 if (bind(sock, (struct sockaddr*)&bind_addr, sizeof(bind_addr))) {
80 syslog(LOG_ERR, "Failed to open DHCPv6 server socket: %s",
85 struct ipv6_mreq relay = {ALL_DHCPV6_RELAYS, iface->ifindex};
86 struct ipv6_mreq server = {ALL_DHCPV6_SERVERS, iface->ifindex};
87 setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &relay, sizeof(relay));
89 if (iface->dhcpv6 == RELAYD_SERVER)
90 setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &server, sizeof(server));
92 iface->dhcpv6_event.uloop.fd = sock;
93 iface->dhcpv6_event.handle_dgram = handle_dhcpv6;
94 odhcpd_register(&iface->dhcpv6_event);
97 return setup_dhcpv6_ia_interface(iface, enable);
104 #define IOV_STAT IOV_MAXRT
110 #define IOV_REFRESH IOV_PDBUF
117 static void handle_nested_message(uint8_t *data, size_t len,
118 uint8_t **opts, uint8_t **end, struct iovec iov[IOV_TOTAL - 1])
120 struct dhcpv6_relay_header *hdr = (struct dhcpv6_relay_header*)data;
121 if (iov[IOV_NESTED].iov_base == NULL) {
122 iov[IOV_NESTED].iov_base = data;
123 iov[IOV_NESTED].iov_len = len;
126 if (len < sizeof(struct dhcpv6_client_header))
129 if (hdr->msg_type != DHCPV6_MSG_RELAY_FORW) {
130 iov[IOV_NESTED].iov_len = data - (uint8_t*)iov[IOV_NESTED].iov_base;
131 struct dhcpv6_client_header *hdr = (void*)data;
132 *opts = (uint8_t*)&hdr[1];
137 uint16_t otype, olen;
139 dhcpv6_for_each_option(hdr->options, data + len, otype, olen, odata) {
140 if (otype == DHCPV6_OPT_RELAY_MSG) {
141 iov[IOV_RELAY_MSG].iov_base = odata + olen;
142 iov[IOV_RELAY_MSG].iov_len = (((uint8_t*)iov[IOV_NESTED].iov_base) +
143 iov[IOV_NESTED].iov_len) - (odata + olen);
144 handle_nested_message(odata, olen, opts, end, iov);
151 static void update_nested_message(uint8_t *data, size_t len, ssize_t pdiff)
153 struct dhcpv6_relay_header *hdr = (struct dhcpv6_relay_header*)data;
154 if (hdr->msg_type != DHCPV6_MSG_RELAY_FORW)
157 hdr->msg_type = DHCPV6_MSG_RELAY_REPL;
159 uint16_t otype, olen;
161 dhcpv6_for_each_option(hdr->options, data + len, otype, olen, odata) {
162 if (otype == DHCPV6_OPT_RELAY_MSG) {
164 odata[-2] = (olen >> 8) & 0xff;
165 odata[-1] = olen & 0xff;
166 update_nested_message(odata, olen - pdiff, pdiff);
172 // Simple DHCPv6-server for information requests
173 static void handle_client_request(void *addr, void *data, size_t len,
174 struct interface *iface, void *dest_addr)
176 struct dhcpv6_client_header *hdr = data;
178 if (len < sizeof(*hdr))
181 syslog(LOG_NOTICE, "Got DHCPv6 request");
183 // Construct reply message
184 struct __attribute__((packed)) {
187 uint16_t serverid_type;
188 uint16_t serverid_length;
190 uint16_t hardware_type;
192 uint16_t clientid_type;
193 uint16_t clientid_length;
194 uint8_t clientid_buf[130];
196 .msg_type = DHCPV6_MSG_REPLY,
197 .serverid_type = htons(DHCPV6_OPT_SERVERID),
198 .serverid_length = htons(10),
199 .duid_type = htons(3),
200 .hardware_type = htons(1),
201 .clientid_type = htons(DHCPV6_OPT_CLIENTID),
204 odhcpd_get_mac(iface, dest.mac);
206 struct __attribute__((packed)) {
210 } maxrt = {htons(DHCPV6_OPT_SOL_MAX_RT), htons(sizeof(maxrt) - 4),
213 struct __attribute__((packed)) {
217 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
218 htons(DHCPV6_STATUS_USEMULTICAST)};
220 struct __attribute__((packed)) {
224 } refresh = {htons(DHCPV6_OPT_INFO_REFRESH), htons(sizeof(uint32_t)),
227 struct odhcpd_ipaddr ipaddr;
228 struct in6_addr *dns_addr = iface->dns;
229 size_t dns_cnt = iface->dns_cnt;
231 if (dns_cnt == 0 && odhcpd_get_interface_addresses(iface->ifindex, &ipaddr, 1) == 1) {
232 dns_addr = &ipaddr.addr;
239 } dns = {htons(DHCPV6_OPT_DNS_SERVERS), htons(dns_cnt * sizeof(*dns_addr))};
243 // DNS Search options
244 uint8_t search_buf[256], *search_domain = iface->search;
245 size_t search_len = iface->search_len;
247 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
248 int len = dn_comp(_res.dnsrch[0], search_buf,
249 sizeof(search_buf), NULL, NULL);
251 search_domain = search_buf;
259 } search = {htons(DHCPV6_OPT_DNS_DOMAIN), htons(search_len)};
262 struct dhcpv6_cer_id cerid = {
264 .type = htons(EXT_CER_ID),
267 .addr = iface->dhcpv6_pd_cer,
272 struct iovec iov[IOV_TOTAL] = {
273 [IOV_NESTED] = {NULL, 0},
274 [IOV_DEST] = {&dest, (uint8_t*)&dest.clientid_type - (uint8_t*)&dest},
275 [IOV_MAXRT] = {&maxrt, sizeof(maxrt)},
276 [IOV_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
277 [IOV_DNS_ADDR] = {dns_addr, dns_cnt * sizeof(*dns_addr)},
278 [IOV_SEARCH] = {&search, (search_len) ? sizeof(search) : 0},
279 [IOV_SEARCH_DOMAIN] = {search_domain, search_len},
280 [IOV_PDBUF] = {pdbuf, 0},
281 [IOV_CERID] = {&cerid, 0},
282 [IOV_DHCPV6_RAW] = {iface->dhcpv6_raw, iface->dhcpv6_raw_len},
283 [IOV_RELAY_MSG] = {NULL, 0}
286 uint8_t *opts = (uint8_t*)&hdr[1], *opts_end = (uint8_t*)data + len;
287 if (hdr->msg_type == DHCPV6_MSG_RELAY_FORW)
288 handle_nested_message(data, len, &opts, &opts_end, iov);
290 memcpy(dest.tr_id, &opts[-3], sizeof(dest.tr_id));
292 if (opts[-4] == DHCPV6_MSG_ADVERTISE || opts[-4] == DHCPV6_MSG_REPLY || opts[-4] == DHCPV6_MSG_RELAY_REPL)
295 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
296 (opts[-4] == DHCPV6_MSG_SOLICIT || opts[-4] == DHCPV6_MSG_CONFIRM ||
297 opts[-4] == DHCPV6_MSG_REBIND || opts[-4] == DHCPV6_MSG_INFORMATION_REQUEST))
300 if (opts[-4] == DHCPV6_MSG_SOLICIT) {
301 dest.msg_type = DHCPV6_MSG_ADVERTISE;
302 } else if (opts[-4] == DHCPV6_MSG_INFORMATION_REQUEST) {
303 iov[IOV_REFRESH].iov_base = &refresh;
304 iov[IOV_REFRESH].iov_len = sizeof(refresh);
306 // Return inf max rt option in reply to information request
307 maxrt.type = htons(DHCPV6_OPT_INF_MAX_RT);
310 // Go through options and find what we need
311 uint16_t otype, olen;
313 dhcpv6_for_each_option(opts, opts_end, otype, olen, odata) {
314 if (otype == DHCPV6_OPT_CLIENTID && olen <= 130) {
315 dest.clientid_length = htons(olen);
316 memcpy(dest.clientid_buf, odata, olen);
317 iov[IOV_DEST].iov_len += 4 + olen;
318 } else if (otype == DHCPV6_OPT_SERVERID) {
319 if (olen != ntohs(dest.serverid_length) ||
320 memcmp(odata, &dest.duid_type, olen))
321 return; // Not for us
322 } else if (iface->filter_class && otype == DHCPV6_OPT_USER_CLASS) {
323 uint8_t *c = odata, *cend = &odata[olen];
324 for (; &c[2] <= cend && &c[2 + (c[0] << 8) + c[1]] <= cend; c = &c[2 + (c[0] << 8) + c[1]]) {
325 size_t elen = strlen(iface->filter_class);
326 if (((((size_t)c[0]) << 8) | c[1]) == elen && !memcmp(&c[2], iface->filter_class, elen))
327 return; // Ignore from homenet
329 } else if (otype == DHCPV6_OPT_IA_PD) {
331 iov[IOV_CERID].iov_len = sizeof(cerid);
333 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)) {
334 struct odhcpd_ipaddr addrs[32];
335 ssize_t len = odhcpd_get_interface_addresses(0, addrs,
336 sizeof(addrs) / sizeof(*addrs));
338 for (ssize_t i = 0; i < len; ++i)
339 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)
340 || memcmp(&addrs[i].addr, &cerid.addr, sizeof(cerid.addr)) < 0)
341 cerid.addr = addrs[i].addr;
347 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
348 (opts[-4] == DHCPV6_MSG_REQUEST || opts[-4] == DHCPV6_MSG_RENEW ||
349 opts[-4] == DHCPV6_MSG_RELEASE || opts[-4] == DHCPV6_MSG_DECLINE)) {
350 iov[IOV_STAT].iov_base = &stat;
351 iov[IOV_STAT].iov_len = sizeof(stat);
353 for (ssize_t i = IOV_STAT + 1; i < IOV_TOTAL; ++i)
356 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
360 if (opts[-4] != DHCPV6_MSG_INFORMATION_REQUEST) {
361 ssize_t ialen = dhcpv6_handle_ia(pdbuf, sizeof(pdbuf), iface, addr, &opts[-4], opts_end);
362 iov[IOV_PDBUF].iov_len = ialen;
363 if (ialen < 0 || (ialen == 0 && (opts[-4] == DHCPV6_MSG_REBIND || opts[-4] == DHCPV6_MSG_CONFIRM)))
367 if (iov[IOV_NESTED].iov_len > 0) // Update length
368 update_nested_message(data, len, iov[IOV_DEST].iov_len + iov[IOV_MAXRT].iov_len +
369 iov[IOV_DNS].iov_len + iov[IOV_DNS_ADDR].iov_len +
370 iov[IOV_SEARCH].iov_len + iov[IOV_SEARCH_DOMAIN].iov_len +
371 iov[IOV_PDBUF].iov_len + iov[IOV_CERID].iov_len +
372 iov[IOV_DHCPV6_RAW].iov_len - (4 + opts_end - opts));
374 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
378 // Central DHCPv6-relay handler
379 static void handle_dhcpv6(void *addr, void *data, size_t len,
380 struct interface *iface, void *dest_addr)
382 if (iface->dhcpv6 == RELAYD_SERVER) {
383 handle_client_request(addr, data, len, iface, dest_addr);
384 } else if (iface->dhcpv6 == RELAYD_RELAY) {
386 relay_server_response(data, len);
388 relay_client_request(addr, data, len, iface);
393 // Relay server response (regular relay server handling)
394 static void relay_server_response(uint8_t *data, size_t len)
396 // Information we need to gather
397 uint8_t *payload_data = NULL;
398 size_t payload_len = 0;
399 int32_t ifaceidx = 0;
400 struct sockaddr_in6 target = {AF_INET6, htons(DHCPV6_CLIENT_PORT),
401 0, IN6ADDR_ANY_INIT, 0};
403 syslog(LOG_NOTICE, "Got a DHCPv6-reply");
406 uint8_t *odata, *end = data + len;
408 // Relay DHCPv6 reply from server to client
409 struct dhcpv6_relay_header *h = (void*)data;
410 if (len < sizeof(*h) || h->msg_type != DHCPV6_MSG_RELAY_REPL)
413 memcpy(&target.sin6_addr, &h->peer_address,
414 sizeof(struct in6_addr));
416 // Go through options and find what we need
417 dhcpv6_for_each_option(h->options, end, otype, olen, odata) {
418 if (otype == DHCPV6_OPT_INTERFACE_ID
419 && olen == sizeof(ifaceidx)) {
420 memcpy(&ifaceidx, odata, sizeof(ifaceidx));
421 } else if (otype == DHCPV6_OPT_RELAY_MSG) {
422 payload_data = odata;
427 // Invalid interface-id or basic payload
428 struct interface *iface = odhcpd_get_interface_by_index(ifaceidx);
429 if (!iface || iface->master || !payload_data || payload_len < 4)
432 bool is_authenticated = false;
433 struct in6_addr *dns_ptr = NULL;
434 size_t dns_count = 0;
436 // If the payload is relay-reply we have to send to the server port
437 if (payload_data[0] == DHCPV6_MSG_RELAY_REPL) {
438 target.sin6_port = htons(DHCPV6_SERVER_PORT);
439 } else { // Go through the payload data
440 struct dhcpv6_client_header *h = (void*)payload_data;
441 end = payload_data + payload_len;
443 dhcpv6_for_each_option(&h[1], end, otype, olen, odata) {
444 if (otype == DHCPV6_OPT_DNS_SERVERS && olen >= 16) {
445 dns_ptr = (struct in6_addr*)odata;
446 dns_count = olen / 16;
447 } else if (otype == DHCPV6_OPT_AUTH) {
448 is_authenticated = true;
453 // Rewrite DNS servers if requested
454 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
455 if (is_authenticated)
456 return; // Impossible to rewrite
458 struct odhcpd_ipaddr ip;
459 const struct in6_addr *rewrite = iface->dns;
460 size_t rewrite_cnt = iface->dns_cnt;
462 if (rewrite_cnt == 0) {
463 if (odhcpd_get_interface_addresses(iface->ifindex, &ip, 1) < 1)
464 return; // Unable to get interface address
470 // Copy over any other addresses
471 for (size_t i = 0; i < dns_count; ++i) {
472 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
473 memcpy(&dns_ptr[i], &rewrite[j], sizeof(*rewrite));
477 struct iovec iov = {payload_data, payload_len};
478 odhcpd_send(iface->dhcpv6_event.uloop.fd, &target, &iov, 1, iface);
482 // Relay client request (regular DHCPv6-relay)
483 static void relay_client_request(struct sockaddr_in6 *source,
484 const void *data, size_t len, struct interface *iface)
486 struct interface *master = odhcpd_get_master_interface();
487 const struct dhcpv6_relay_header *h = data;
488 if (!master || master->dhcpv6 != RELAYD_RELAY ||
489 h->msg_type == DHCPV6_MSG_RELAY_REPL ||
490 h->msg_type == DHCPV6_MSG_RECONFIGURE ||
491 h->msg_type == DHCPV6_MSG_REPLY ||
492 h->msg_type == DHCPV6_MSG_ADVERTISE)
493 return; // Invalid message types for client
495 syslog(LOG_NOTICE, "Got a DHCPv6-request");
497 // Construct our forwarding envelope
498 struct dhcpv6_relay_forward_envelope hdr = {
499 .msg_type = DHCPV6_MSG_RELAY_FORW,
501 .interface_id_type = htons(DHCPV6_OPT_INTERFACE_ID),
502 .interface_id_len = htons(sizeof(uint32_t)),
503 .relay_message_type = htons(DHCPV6_OPT_RELAY_MSG),
504 .relay_message_len = htons(len),
507 if (h->msg_type == DHCPV6_MSG_RELAY_FORW) { // handle relay-forward
508 if (h->hop_count >= DHCPV6_HOP_COUNT_LIMIT)
509 return; // Invalid hop count
511 hdr.hop_count = h->hop_count + 1;
514 // use memcpy here as the destination fields are unaligned
515 uint32_t ifindex = iface->ifindex;
516 memcpy(&hdr.peer_address, &source->sin6_addr, sizeof(struct in6_addr));
517 memcpy(&hdr.interface_id_data, &ifindex, sizeof(ifindex));
519 // Detect public IP of slave interface to use as link-address
520 struct odhcpd_ipaddr ip;
521 if (odhcpd_get_interface_addresses(iface->ifindex, &ip, 1) < 1) {
522 // No suitable address! Is the slave not configured yet?
523 // Detect public IP of master interface and use it instead
524 // This is WRONG and probably violates the RFC. However
525 // otherwise we have a hen and egg problem because the
526 // slave-interface cannot be auto-configured.
527 if (odhcpd_get_interface_addresses(master->ifindex, &ip, 1) < 1)
528 return; // Could not obtain a suitable address
530 memcpy(&hdr.link_address, &ip.addr, sizeof(hdr.link_address));
532 struct sockaddr_in6 dhcpv6_servers = {AF_INET6,
533 htons(DHCPV6_SERVER_PORT), 0, ALL_DHCPV6_SERVERS, 0};
534 struct iovec iov[2] = {{&hdr, sizeof(hdr)}, {(void*)data, len}};
535 odhcpd_send(iface->dhcpv6_event.uloop.fd, &dhcpv6_servers, iov, 2, master);