1 /** 2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org> 3 * Copyright (C) 2018 Hans Dedecker <dedeckeh@gmail.com> 4 * 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. 8 * 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. 13 * 14 * 15 */ 16 17 #include <errno.h> 18 #include <unistd.h> 19 #include <stddef.h> 20 #include <resolv.h> 21 #include <sys/timerfd.h> 22 #include <arpa/inet.h> 23 24 #include <libubox/utils.h> 25 26 #include "odhcpd.h" 27 #include "dhcpv6.h" 28 29 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); 33 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); 38 39 40 /* Create socket and register events */ 41 int dhcpv6_init(void) 42 { 43 return dhcpv6_ia_init(); 44 } 45 46 int dhcpv6_setup_interface(struct interface *iface, bool enable) 47 { 48 int ret = 0; 49 50 enable = enable && (iface->dhcpv6 != MODE_DISABLED); 51 52 if (iface->dhcpv6_event.uloop.fd >= 0) { 53 uloop_fd_delete(&iface->dhcpv6_event.uloop); 54 close(iface->dhcpv6_event.uloop.fd); 55 iface->dhcpv6_event.uloop.fd = -1; 56 } 57 58 /* Configure multicast settings */ 59 if (enable) { 60 struct sockaddr_in6 bind_addr = {AF_INET6, htons(DHCPV6_SERVER_PORT), 61 0, IN6ADDR_ANY_INIT, 0}; 62 struct ipv6_mreq mreq; 63 int val = 1; 64 65 iface->dhcpv6_event.uloop.fd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP); 66 if (iface->dhcpv6_event.uloop.fd < 0) { 67 syslog(LOG_ERR, "socket(AF_INET6): %m"); 68 ret = -1; 69 goto out; 70 } 71 72 /* Basic IPv6 configuration */ 73 if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE, 74 iface->ifname, strlen(iface->ifname)) < 0) { 75 syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m"); 76 ret = -1; 77 goto out; 78 } 79 80 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_V6ONLY, 81 &val, sizeof(val)) < 0) { 82 syslog(LOG_ERR, "setsockopt(IPV6_V6ONLY): %m"); 83 ret = -1; 84 goto out; 85 } 86 87 if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR, 88 &val, sizeof(val)) < 0) { 89 syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m"); 90 ret = -1; 91 goto out; 92 } 93 94 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, 95 &val, sizeof(val)) < 0) { 96 syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m"); 97 ret = -1; 98 goto out; 99 } 100 101 val = DHCPV6_HOP_COUNT_LIMIT; 102 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, 103 &val, sizeof(val)) < 0) { 104 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m"); 105 ret = -1; 106 goto out; 107 } 108 109 val = 0; 110 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, 111 &val, sizeof(val)) < 0) { 112 syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m"); 113 ret = -1; 114 goto out; 115 } 116 117 if (bind(iface->dhcpv6_event.uloop.fd, (struct sockaddr*)&bind_addr, 118 sizeof(bind_addr)) < 0) { 119 syslog(LOG_ERR, "bind(): %m"); 120 ret = -1; 121 goto out; 122 } 123 124 memset(&mreq, 0, sizeof(mreq)); 125 inet_pton(AF_INET6, ALL_DHCPV6_RELAYS, &mreq.ipv6mr_multiaddr); 126 mreq.ipv6mr_interface = iface->ifindex; 127 128 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, 129 &mreq, sizeof(mreq)) < 0) { 130 syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m"); 131 ret = -1; 132 goto out; 133 } 134 135 if (iface->dhcpv6 == MODE_SERVER) { 136 memset(&mreq, 0, sizeof(mreq)); 137 inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &mreq.ipv6mr_multiaddr); 138 mreq.ipv6mr_interface = iface->ifindex; 139 140 if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, 141 &mreq, sizeof(mreq)) < 0) { 142 syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m"); 143 ret = -1; 144 goto out; 145 } 146 } 147 148 iface->dhcpv6_event.handle_dgram = handle_dhcpv6; 149 odhcpd_register(&iface->dhcpv6_event); 150 } 151 152 ret = dhcpv6_ia_setup_interface(iface, enable); 153 154 out: 155 if (ret < 0 && iface->dhcpv6_event.uloop.fd >= 0) { 156 close(iface->dhcpv6_event.uloop.fd); 157 iface->dhcpv6_event.uloop.fd = -1; 158 } 159 160 return ret; 161 } 162 163 enum { 164 IOV_NESTED = 0, 165 IOV_DEST, 166 IOV_MAXRT, 167 #define IOV_STAT IOV_MAXRT 168 IOV_RAPID_COMMIT, 169 IOV_DNS, 170 IOV_DNS_ADDR, 171 IOV_SEARCH, 172 IOV_SEARCH_DOMAIN, 173 IOV_PDBUF, 174 #define IOV_REFRESH IOV_PDBUF 175 IOV_CERID, 176 IOV_DHCPV6_RAW, 177 IOV_RELAY_MSG, 178 IOV_TOTAL 179 }; 180 181 static void handle_nested_message(uint8_t *data, size_t len, 182 struct dhcpv6_client_header **c_hdr, uint8_t **opts, 183 uint8_t **end, struct iovec iov[IOV_TOTAL]) 184 { 185 struct dhcpv6_relay_header *r_hdr = (struct dhcpv6_relay_header *)data; 186 uint16_t otype, olen; 187 uint8_t *odata; 188 189 if (iov[IOV_NESTED].iov_base == NULL) { 190 iov[IOV_NESTED].iov_base = data; 191 iov[IOV_NESTED].iov_len = len; 192 } 193 194 if (len < sizeof(struct dhcpv6_client_header)) 195 return; 196 197 if (r_hdr->msg_type != DHCPV6_MSG_RELAY_FORW) { 198 iov[IOV_NESTED].iov_len = data - (uint8_t *)iov[IOV_NESTED].iov_base; 199 *c_hdr = (void *)data; 200 *opts = (uint8_t *)&(*c_hdr)[1]; 201 *end = data + len; 202 return; 203 } 204 205 dhcpv6_for_each_option(r_hdr->options, data + len, otype, olen, odata) { 206 if (otype == DHCPV6_OPT_RELAY_MSG) { 207 iov[IOV_RELAY_MSG].iov_base = odata + olen; 208 iov[IOV_RELAY_MSG].iov_len = (((uint8_t *)iov[IOV_NESTED].iov_base) + 209 iov[IOV_NESTED].iov_len) - (odata + olen); 210 handle_nested_message(odata, olen, c_hdr, opts, end, iov); 211 return; 212 } 213 } 214 } 215 216 217 static void update_nested_message(uint8_t *data, size_t len, ssize_t pdiff) 218 { 219 struct dhcpv6_relay_header *hdr = (struct dhcpv6_relay_header*)data; 220 if (hdr->msg_type != DHCPV6_MSG_RELAY_FORW) 221 return; 222 223 hdr->msg_type = DHCPV6_MSG_RELAY_REPL; 224 225 uint16_t otype, olen; 226 uint8_t *odata; 227 dhcpv6_for_each_option(hdr->options, data + len, otype, olen, odata) { 228 if (otype == DHCPV6_OPT_RELAY_MSG) { 229 olen += pdiff; 230 odata[-2] = (olen >> 8) & 0xff; 231 odata[-1] = olen & 0xff; 232 update_nested_message(odata, olen - pdiff, pdiff); 233 return; 234 } 235 } 236 } 237 238 /* Simple DHCPv6-server for information requests */ 239 static void handle_client_request(void *addr, void *data, size_t len, 240 struct interface *iface, void *dest_addr) 241 { 242 struct dhcpv6_client_header *hdr = data; 243 uint8_t *opts = (uint8_t *)&hdr[1], *opts_end = (uint8_t *)data + len; 244 bool o_rapid_commit = false; 245 246 if (len < sizeof(*hdr)) 247 return; 248 249 syslog(LOG_DEBUG, "Got a DHCPv6-request on %s", iface->name); 250 251 /* Construct reply message */ 252 struct __attribute__((packed)) { 253 uint8_t msg_type; 254 uint8_t tr_id[3]; 255 uint16_t serverid_type; 256 uint16_t serverid_length; 257 uint16_t duid_type; 258 uint16_t hardware_type; 259 uint8_t mac[6]; 260 uint16_t clientid_type; 261 uint16_t clientid_length; 262 uint8_t clientid_buf[130]; 263 } dest = { 264 .msg_type = DHCPV6_MSG_REPLY, 265 .serverid_type = htons(DHCPV6_OPT_SERVERID), 266 .serverid_length = htons(10), 267 .duid_type = htons(3), 268 .hardware_type = htons(1), 269 .clientid_type = htons(DHCPV6_OPT_CLIENTID), 270 .clientid_buf = {0} 271 }; 272 odhcpd_get_mac(iface, dest.mac); 273 274 struct __attribute__((packed)) { 275 uint16_t type; 276 uint16_t len; 277 uint32_t value; 278 } maxrt = {htons(DHCPV6_OPT_SOL_MAX_RT), htons(sizeof(maxrt) - 4), 279 htonl(60)}; 280 281 struct __attribute__((packed)) { 282 uint16_t type; 283 uint16_t len; 284 } rapid_commit = {htons(DHCPV6_OPT_RAPID_COMMIT), 0}; 285 286 struct __attribute__((packed)) { 287 uint16_t type; 288 uint16_t len; 289 uint16_t value; 290 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4), 291 htons(DHCPV6_STATUS_USEMULTICAST)}; 292 293 struct __attribute__((packed)) { 294 uint16_t type; 295 uint16_t len; 296 uint32_t value; 297 } refresh = {htons(DHCPV6_OPT_INFO_REFRESH), htons(sizeof(uint32_t)), 298 htonl(600)}; 299 300 struct in6_addr dns_addr, *dns_addr_ptr = iface->dns; 301 size_t dns_cnt = iface->dns_cnt; 302 303 if ((dns_cnt == 0) && 304 !odhcpd_get_interface_dns_addr(iface, &dns_addr)) { 305 dns_addr_ptr = &dns_addr; 306 dns_cnt = 1; 307 } 308 309 struct { 310 uint16_t type; 311 uint16_t len; 312 } dns = {htons(DHCPV6_OPT_DNS_SERVERS), htons(dns_cnt * sizeof(*dns_addr_ptr))}; 313 314 315 316 /* DNS Search options */ 317 uint8_t search_buf[256], *search_domain = iface->search; 318 size_t search_len = iface->search_len; 319 320 if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) { 321 int len = dn_comp(_res.dnsrch[0], search_buf, 322 sizeof(search_buf), NULL, NULL); 323 if (len > 0) { 324 search_domain = search_buf; 325 search_len = len; 326 } 327 } 328 329 struct { 330 uint16_t type; 331 uint16_t len; 332 } search = {htons(DHCPV6_OPT_DNS_DOMAIN), htons(search_len)}; 333 334 335 struct dhcpv6_cer_id cerid = { 336 #ifdef EXT_CER_ID 337 .type = htons(EXT_CER_ID), 338 #endif 339 .len = htons(36), 340 .addr = iface->dhcpv6_pd_cer, 341 }; 342 343 344 uint8_t pdbuf[512]; 345 struct iovec iov[IOV_TOTAL] = { 346 [IOV_NESTED] = {NULL, 0}, 347 [IOV_DEST] = {&dest, (uint8_t*)&dest.clientid_type - (uint8_t*)&dest}, 348 [IOV_MAXRT] = {&maxrt, sizeof(maxrt)}, 349 [IOV_RAPID_COMMIT] = {&rapid_commit, 0}, 350 [IOV_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0}, 351 [IOV_DNS_ADDR] = {dns_addr_ptr, dns_cnt * sizeof(*dns_addr_ptr)}, 352 [IOV_SEARCH] = {&search, (search_len) ? sizeof(search) : 0}, 353 [IOV_SEARCH_DOMAIN] = {search_domain, search_len}, 354 [IOV_PDBUF] = {pdbuf, 0}, 355 [IOV_CERID] = {&cerid, 0}, 356 [IOV_DHCPV6_RAW] = {iface->dhcpv6_raw, iface->dhcpv6_raw_len}, 357 [IOV_RELAY_MSG] = {NULL, 0} 358 }; 359 360 if (hdr->msg_type == DHCPV6_MSG_RELAY_FORW) 361 handle_nested_message(data, len, &hdr, &opts, &opts_end, iov); 362 363 if (hdr->msg_type == DHCPV6_MSG_ADVERTISE || hdr->msg_type == DHCPV6_MSG_REPLY || 364 hdr->msg_type == DHCPV6_MSG_RELAY_REPL) 365 return; 366 367 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 && 368 (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_CONFIRM || 369 hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST)) 370 return; 371 372 memcpy(dest.tr_id, hdr->transaction_id, sizeof(dest.tr_id)); 373 374 /* Go through options and find what we need */ 375 uint16_t otype, olen; 376 uint8_t *odata; 377 dhcpv6_for_each_option(opts, opts_end, otype, olen, odata) { 378 if (otype == DHCPV6_OPT_CLIENTID && olen <= 130) { 379 dest.clientid_length = htons(olen); 380 memcpy(dest.clientid_buf, odata, olen); 381 iov[IOV_DEST].iov_len += 4 + olen; 382 } else if (otype == DHCPV6_OPT_SERVERID) { 383 if (olen != ntohs(dest.serverid_length) || 384 memcmp(odata, &dest.duid_type, olen)) 385 return; /* Not for us */ 386 } else if (iface->filter_class && otype == DHCPV6_OPT_USER_CLASS) { 387 uint8_t *c = odata, *cend = &odata[olen]; 388 for (; &c[2] <= cend && &c[2 + (c[0] << 8) + c[1]] <= cend; c = &c[2 + (c[0] << 8) + c[1]]) { 389 size_t elen = strlen(iface->filter_class); 390 if (((((size_t)c[0]) << 8) | c[1]) == elen && !memcmp(&c[2], iface->filter_class, elen)) 391 return; /* Ignore from homenet */ 392 } 393 } else if (otype == DHCPV6_OPT_IA_PD) { 394 #ifdef EXT_CER_ID 395 iov[IOV_CERID].iov_len = sizeof(cerid); 396 397 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)) { 398 struct odhcpd_ipaddr *addrs; 399 ssize_t len = netlink_get_interface_addrs(0, true, &addrs); 400 401 for (ssize_t i = 0; i < len; ++i) 402 if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr) 403 || memcmp(&addrs[i].addr, &cerid.addr, sizeof(cerid.addr)) < 0) 404 cerid.addr = addrs[i].addr.in6; 405 406 free(addrs); 407 } 408 #endif 409 } else if (otype == DHCPV6_OPT_RAPID_COMMIT && hdr->msg_type == DHCPV6_MSG_SOLICIT) { 410 iov[IOV_RAPID_COMMIT].iov_len = sizeof(rapid_commit); 411 o_rapid_commit = true; 412 } 413 } 414 415 if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 && 416 (hdr->msg_type == DHCPV6_MSG_REQUEST || hdr->msg_type == DHCPV6_MSG_RENEW || 417 hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE)) { 418 iov[IOV_STAT].iov_base = &stat; 419 iov[IOV_STAT].iov_len = sizeof(stat); 420 421 for (ssize_t i = IOV_STAT + 1; i < IOV_TOTAL; ++i) 422 iov[i].iov_len = 0; 423 424 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface); 425 return; 426 } 427 428 if (hdr->msg_type == DHCPV6_MSG_SOLICIT && !o_rapid_commit) { 429 dest.msg_type = DHCPV6_MSG_ADVERTISE; 430 } else if (hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST) { 431 iov[IOV_REFRESH].iov_base = &refresh; 432 iov[IOV_REFRESH].iov_len = sizeof(refresh); 433 434 /* Return inf max rt option in reply to information request */ 435 maxrt.type = htons(DHCPV6_OPT_INF_MAX_RT); 436 } 437 438 if (hdr->msg_type != DHCPV6_MSG_INFORMATION_REQUEST) { 439 ssize_t ialen = dhcpv6_ia_handle_IAs(pdbuf, sizeof(pdbuf), iface, addr, (const void *)hdr, opts_end); 440 441 iov[IOV_PDBUF].iov_len = ialen; 442 if (ialen < 0 || 443 (ialen == 0 && (hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_CONFIRM))) 444 return; 445 } 446 447 if (iov[IOV_NESTED].iov_len > 0) /* Update length */ 448 update_nested_message(data, len, iov[IOV_DEST].iov_len + iov[IOV_MAXRT].iov_len + 449 iov[IOV_RAPID_COMMIT].iov_len + iov[IOV_DNS].iov_len + 450 iov[IOV_DNS_ADDR].iov_len + iov[IOV_SEARCH].iov_len + 451 iov[IOV_SEARCH_DOMAIN].iov_len + iov[IOV_PDBUF].iov_len + 452 iov[IOV_CERID].iov_len + iov[IOV_DHCPV6_RAW].iov_len - 453 (4 + opts_end - opts)); 454 455 syslog(LOG_DEBUG, "Sending a DHCPv6-%s on %s", iov[IOV_NESTED].iov_len ? "relay-reply" : "reply", iface->name); 456 457 odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface); 458 } 459 460 461 /* Central DHCPv6-relay handler */ 462 static void handle_dhcpv6(void *addr, void *data, size_t len, 463 struct interface *iface, void *dest_addr) 464 { 465 if (iface->dhcpv6 == MODE_SERVER) { 466 handle_client_request(addr, data, len, iface, dest_addr); 467 } else if (iface->dhcpv6 == MODE_RELAY) { 468 if (iface->master) 469 relay_server_response(data, len); 470 else 471 relay_client_request(addr, data, len, iface); 472 } 473 } 474 475 476 /* Relay server response (regular relay server handling) */ 477 static void relay_server_response(uint8_t *data, size_t len) 478 { 479 /* Information we need to gather */ 480 uint8_t *payload_data = NULL; 481 size_t payload_len = 0; 482 int32_t ifaceidx = 0; 483 struct sockaddr_in6 target = {AF_INET6, htons(DHCPV6_CLIENT_PORT), 484 0, IN6ADDR_ANY_INIT, 0}; 485 int otype, olen; 486 uint8_t *odata, *end = data + len; 487 /* Relay DHCPv6 reply from server to client */ 488 struct dhcpv6_relay_header *h = (void*)data; 489 490 syslog(LOG_DEBUG, "Got a DHCPv6-relay-reply"); 491 492 if (len < sizeof(*h) || h->msg_type != DHCPV6_MSG_RELAY_REPL) 493 return; 494 495 memcpy(&target.sin6_addr, &h->peer_address, sizeof(struct in6_addr)); 496 497 /* Go through options and find what we need */ 498 dhcpv6_for_each_option(h->options, end, otype, olen, odata) { 499 if (otype == DHCPV6_OPT_INTERFACE_ID 500 && olen == sizeof(ifaceidx)) { 501 memcpy(&ifaceidx, odata, sizeof(ifaceidx)); 502 } else if (otype == DHCPV6_OPT_RELAY_MSG) { 503 payload_data = odata; 504 payload_len = olen; 505 } 506 } 507 508 /* Invalid interface-id or basic payload */ 509 struct interface *iface = odhcpd_get_interface_by_index(ifaceidx); 510 if (!iface || iface->master || !payload_data || payload_len < 4) 511 return; 512 513 bool is_authenticated = false; 514 struct in6_addr *dns_ptr = NULL; 515 size_t dns_count = 0; 516 517 /* If the payload is relay-reply we have to send to the server port */ 518 if (payload_data[0] == DHCPV6_MSG_RELAY_REPL) { 519 target.sin6_port = htons(DHCPV6_SERVER_PORT); 520 } else { /* Go through the payload data */ 521 struct dhcpv6_client_header *h = (void*)payload_data; 522 end = payload_data + payload_len; 523 524 dhcpv6_for_each_option(&h[1], end, otype, olen, odata) { 525 if (otype == DHCPV6_OPT_DNS_SERVERS && olen >= 16) { 526 dns_ptr = (struct in6_addr*)odata; 527 dns_count = olen / 16; 528 } else if (otype == DHCPV6_OPT_AUTH) { 529 is_authenticated = true; 530 } 531 } 532 } 533 534 /* Rewrite DNS servers if requested */ 535 if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) { 536 if (is_authenticated) 537 return; /* Impossible to rewrite */ 538 539 const struct in6_addr *rewrite = iface->dns; 540 struct in6_addr addr; 541 size_t rewrite_cnt = iface->dns_cnt; 542 543 if (rewrite_cnt == 0) { 544 if (odhcpd_get_interface_dns_addr(iface, &addr)) 545 return; /* Unable to get interface address */ 546 547 rewrite = &addr; 548 rewrite_cnt = 1; 549 } 550 551 /* Copy over any other addresses */ 552 for (size_t i = 0; i < dns_count; ++i) { 553 size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1; 554 memcpy(&dns_ptr[i], &rewrite[j], sizeof(*rewrite)); 555 } 556 } 557 558 struct iovec iov = {payload_data, payload_len}; 559 560 syslog(LOG_DEBUG, "Sending a DHCPv6-reply on %s", iface->name); 561 562 odhcpd_send(iface->dhcpv6_event.uloop.fd, &target, &iov, 1, iface); 563 } 564 565 static struct odhcpd_ipaddr *relay_link_address(struct interface *iface) 566 { 567 struct odhcpd_ipaddr *addr = NULL; 568 time_t now = odhcpd_time(); 569 570 for (size_t i = 0; i < iface->addr6_len; i++) { 571 if (iface->addr6[i].valid <= (uint32_t)now) 572 continue; 573 574 if (iface->addr6[i].preferred > (uint32_t)now) { 575 addr = &iface->addr6[i]; 576 break; 577 } 578 579 if (!addr || (iface->addr6[i].valid > addr->valid)) 580 addr = &iface->addr6[i]; 581 } 582 583 return addr; 584 } 585 586 /* Relay client request (regular DHCPv6-relay) */ 587 static void relay_client_request(struct sockaddr_in6 *source, 588 const void *data, size_t len, struct interface *iface) 589 { 590 const struct dhcpv6_relay_header *h = data; 591 /* Construct our forwarding envelope */ 592 struct dhcpv6_relay_forward_envelope hdr = { 593 .msg_type = DHCPV6_MSG_RELAY_FORW, 594 .hop_count = 0, 595 .interface_id_type = htons(DHCPV6_OPT_INTERFACE_ID), 596 .interface_id_len = htons(sizeof(uint32_t)), 597 .relay_message_type = htons(DHCPV6_OPT_RELAY_MSG), 598 .relay_message_len = htons(len), 599 }; 600 struct iovec iov[2] = {{&hdr, sizeof(hdr)}, {(void *)data, len}}; 601 struct interface *c; 602 struct odhcpd_ipaddr *ip; 603 struct sockaddr_in6 s; 604 605 if (h->msg_type == DHCPV6_MSG_RELAY_REPL || 606 h->msg_type == DHCPV6_MSG_RECONFIGURE || 607 h->msg_type == DHCPV6_MSG_REPLY || 608 h->msg_type == DHCPV6_MSG_ADVERTISE) 609 return; /* Invalid message types for client */ 610 611 syslog(LOG_DEBUG, "Got a DHCPv6-request on %s", iface->name); 612 613 if (h->msg_type == DHCPV6_MSG_RELAY_FORW) { /* handle relay-forward */ 614 if (h->hop_count >= DHCPV6_HOP_COUNT_LIMIT) 615 return; /* Invalid hop count */ 616 617 hdr.hop_count = h->hop_count + 1; 618 } 619 620 /* use memcpy here as the destination fields are unaligned */ 621 memcpy(&hdr.peer_address, &source->sin6_addr, sizeof(struct in6_addr)); 622 memcpy(&hdr.interface_id_data, &iface->ifindex, sizeof(iface->ifindex)); 623 624 /* Detect public IP of slave interface to use as link-address */ 625 ip = relay_link_address(iface); 626 if (ip) 627 memcpy(&hdr.link_address, &ip->addr.in6, sizeof(hdr.link_address)); 628 629 memset(&s, 0, sizeof(s)); 630 s.sin6_family = AF_INET6; 631 s.sin6_port = htons(DHCPV6_SERVER_PORT); 632 inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &s.sin6_addr); 633 634 avl_for_each_element(&interfaces, c, avl) { 635 if (!c->master || c->dhcpv6 != MODE_RELAY) 636 continue; 637 638 if (!ip) { 639 /* No suitable address! Is the slave not configured yet? 640 * Detect public IP of master interface and use it instead 641 * This is WRONG and probably violates the RFC. However 642 * otherwise we have a hen and egg problem because the 643 * slave-interface cannot be auto-configured. */ 644 ip = relay_link_address(c); 645 if (!ip) 646 continue; /* Could not obtain a suitable address */ 647 648 memcpy(&hdr.link_address, &ip->addr.in6, sizeof(hdr.link_address)); 649 ip = NULL; 650 } 651 652 syslog(LOG_DEBUG, "Sending a DHCPv6-relay-forward on %s", c->name); 653 654 odhcpd_send(c->dhcpv6_event.uloop.fd, &s, iov, 2, c); 655 } 656 } 657
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