1 /** 2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org> 3 * Copyright (C) 2017-2018 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 #include <time.h> 17 #include <fcntl.h> 18 #include <errno.h> 19 #include <inttypes.h> 20 #include <stdlib.h> 21 #include <signal.h> 22 #include <limits.h> 23 #include <resolv.h> 24 #include <string.h> 25 #include <unistd.h> 26 #include <syslog.h> 27 #include <stdbool.h> 28 #include <ctype.h> 29 #include <sys/time.h> 30 #include <sys/ioctl.h> 31 #include <sys/socket.h> 32 #include <arpa/inet.h> 33 #include <netinet/in.h> 34 35 #include <net/if.h> 36 #include <net/ethernet.h> 37 38 #include "odhcp6c.h" 39 #ifdef USE_LIBUBOX 40 #include <libubox/md5.h> 41 #else 42 #include "md5.h" 43 #endif 44 45 46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\ 47 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}} 48 #define DHCPV6_CLIENT_PORT 546 49 #define DHCPV6_SERVER_PORT 547 50 #define DHCPV6_DUID_LLADDR 3 51 #define DHCPV6_REQ_DELAY 1 52 53 #define DHCPV6_SOL_MAX_RT_MIN 60 54 #define DHCPV6_SOL_MAX_RT_MAX 86400 55 #define DHCPV6_INF_MAX_RT_MIN 60 56 #define DHCPV6_INF_MAX_RT_MAX 86400 57 58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len, 59 const uint8_t transaction[3], enum dhcpv6_msg type, 60 const struct in6_addr *daddr); 61 62 static unsigned int dhcpv6_parse_ia(void *opt, void *end); 63 64 static unsigned int dhcpv6_calc_refresh_timers(void); 65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig, 66 const uint16_t code, const void *status_msg, const int len, 67 int *ret); 68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig, 69 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code, 70 const void *status_msg, const int len, 71 bool handled_status_codes[_DHCPV6_Status_Max], 72 int *ret); 73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand); 74 static void dhcpv6_clear_all_server_cand(void); 75 76 static reply_handler dhcpv6_handle_reply; 77 static reply_handler dhcpv6_handle_advert; 78 static reply_handler dhcpv6_handle_rebind_reply; 79 static reply_handler dhcpv6_handle_reconfigure; 80 static int dhcpv6_commit_advert(void); 81 82 // RFC 3315 - 5.5 Timeout and Delay values 83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = { 84 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>", 85 dhcpv6_handle_reconfigure, NULL}, 86 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT", 87 dhcpv6_handle_advert, dhcpv6_commit_advert}, 88 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST", 89 dhcpv6_handle_reply, NULL}, 90 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW", 91 dhcpv6_handle_reply, NULL}, 92 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND", 93 dhcpv6_handle_rebind_reply, NULL}, 94 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL}, 95 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL}, 96 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ", 97 dhcpv6_handle_reply, NULL}, 98 }; 99 100 // Sockets 101 static int sock = -1; 102 static int ifindex = -1; 103 static int64_t t1 = 0, t2 = 0, t3 = 0; 104 105 // IA states 106 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE; 107 static bool stateful_only_mode = false; 108 static bool accept_reconfig = false; 109 // Server unicast address 110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT; 111 112 // Reconfigure key 113 static uint8_t reconf_key[16]; 114 115 // client options 116 static unsigned int client_options = 0; 117 118 static uint32_t ntohl_unaligned(const uint8_t *data) 119 { 120 uint32_t buf; 121 122 memcpy(&buf, data, sizeof(buf)); 123 return ntohl(buf); 124 } 125 126 static char *dhcpv6_msg_to_str(enum dhcpv6_msg msg) 127 { 128 switch (msg) { 129 case DHCPV6_MSG_SOLICIT: 130 return "SOLICIT"; 131 132 case DHCPV6_MSG_ADVERT: 133 return "ADVERTISE"; 134 135 case DHCPV6_MSG_REQUEST: 136 return "REQUEST"; 137 138 case DHCPV6_MSG_RENEW: 139 return "RENEW"; 140 141 case DHCPV6_MSG_REBIND: 142 return "REBIND"; 143 144 case DHCPV6_MSG_REPLY: 145 return "REPLY"; 146 147 case DHCPV6_MSG_RELEASE: 148 return "RELEASE"; 149 150 case DHCPV6_MSG_DECLINE: 151 return "DECLINE"; 152 153 case DHCPV6_MSG_RECONF: 154 return "RECONFIGURE"; 155 156 case DHCPV6_MSG_INFO_REQ: 157 return "INFORMATION REQUEST"; 158 159 default: 160 break; 161 } 162 163 return "UNKNOWN"; 164 } 165 166 static char *dhcpv6_status_code_to_str(uint16_t code) 167 { 168 switch (code) { 169 case DHCPV6_Success: 170 return "Success"; 171 172 case DHCPV6_UnspecFail: 173 return "Unspecified Failure"; 174 175 case DHCPV6_NoAddrsAvail: 176 return "No Address Available"; 177 178 case DHCPV6_NoBinding: 179 return "No Binding"; 180 181 case DHCPV6_NotOnLink: 182 return "Not On Link"; 183 184 case DHCPV6_UseMulticast: 185 return "Use Multicast"; 186 187 case DHCPV6_NoPrefixAvail: 188 return "No Prefix Available"; 189 190 default: 191 break; 192 } 193 194 return "Unknown"; 195 } 196 197 int init_dhcpv6(const char *ifname, unsigned int options, int sk_prio, int sol_timeout) 198 { 199 client_options = options; 200 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout; 201 202 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP); 203 if (sock < 0) 204 goto failure; 205 206 // Detect interface 207 struct ifreq ifr; 208 memset(&ifr, 0, sizeof(ifr)); 209 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1); 210 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0) 211 goto failure; 212 213 ifindex = ifr.ifr_ifindex; 214 215 // Create client DUID 216 size_t client_id_len; 217 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len); 218 if (client_id_len == 0) { 219 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0, 220 DHCPV6_DUID_LLADDR, 0, 1}; 221 222 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0) 223 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN); 224 225 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0}; 226 struct ifreq ifs[100], *ifp, *ifend; 227 struct ifconf ifc; 228 ifc.ifc_req = ifs; 229 ifc.ifc_len = sizeof(ifs); 230 231 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) && 232 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) { 233 // If our interface doesn't have an address... 234 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq)); 235 for (ifp = ifc.ifc_req; ifp < ifend && 236 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) { 237 memcpy(ifr.ifr_name, ifp->ifr_name, 238 sizeof(ifr.ifr_name)); 239 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0) 240 continue; 241 242 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, 243 ETHER_ADDR_LEN); 244 } 245 } 246 247 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid)); 248 } 249 250 // Create ORO 251 if (!(client_options & DHCPV6_STRICT_OPTIONS)) { 252 uint16_t oro[] = { 253 htons(DHCPV6_OPT_SIP_SERVER_D), 254 htons(DHCPV6_OPT_SIP_SERVER_A), 255 htons(DHCPV6_OPT_DNS_SERVERS), 256 htons(DHCPV6_OPT_DNS_DOMAIN), 257 htons(DHCPV6_OPT_SNTP_SERVERS), 258 htons(DHCPV6_OPT_NTP_SERVER), 259 htons(DHCPV6_OPT_PD_EXCLUDE), 260 #ifdef EXT_CER_ID 261 htons(DHCPV6_OPT_CER_ID), 262 #endif 263 }; 264 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro)); 265 } 266 // Required oro 267 uint16_t req_oro[] = { 268 htons(DHCPV6_OPT_INF_MAX_RT), 269 htons(DHCPV6_OPT_SOL_MAX_RT), 270 htons(DHCPV6_OPT_INFO_REFRESH), 271 }; 272 odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro)); 273 274 // Configure IPv6-options 275 int val = 1; 276 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0) 277 goto failure; 278 279 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0) 280 goto failure; 281 282 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0) 283 goto failure; 284 285 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0) 286 goto failure; 287 288 if (setsockopt(sock, SOL_SOCKET, SO_PRIORITY, &sk_prio, sizeof(sk_prio)) < 0) 289 goto failure; 290 291 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6, 292 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 }; 293 294 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0) 295 goto failure; 296 297 return 0; 298 299 failure: 300 if (sock >= 0) 301 close(sock); 302 303 return -1; 304 } 305 306 enum { 307 IOV_HDR=0, 308 IOV_ORO, 309 IOV_CL_ID, 310 IOV_SRV_ID, 311 IOV_OPTS, 312 IOV_RECONF_ACCEPT, 313 IOV_FQDN, 314 IOV_HDR_IA_NA, 315 IOV_IA_NA, 316 IOV_IA_PD, 317 IOV_TOTAL 318 }; 319 320 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd, bool stateful_only) 321 { 322 int mode = DHCPV6_UNKNOWN; 323 324 na_mode = na; 325 pd_mode = pd; 326 stateful_only_mode = stateful_only; 327 328 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) 329 mode = DHCPV6_STATELESS; 330 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE) 331 mode = DHCPV6_STATEFUL; 332 333 return mode; 334 } 335 336 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs) 337 { 338 // Build FQDN 339 char fqdn_buf[256]; 340 gethostname(fqdn_buf, sizeof(fqdn_buf)); 341 struct { 342 uint16_t type; 343 uint16_t len; 344 uint8_t flags; 345 uint8_t data[256]; 346 } fqdn; 347 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data, 348 sizeof(fqdn.data), NULL, NULL); 349 fqdn.type = htons(DHCPV6_OPT_FQDN); 350 fqdn.len = htons(fqdn_len - 4); 351 fqdn.flags = 0; 352 353 // Build Client ID 354 size_t cl_id_len; 355 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len); 356 357 // Get Server ID 358 size_t srv_id_len; 359 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len); 360 361 // Build IA_PDs 362 size_t ia_pd_entries = 0, ia_pd_len = 0; 363 uint8_t *ia_pd; 364 365 if (type == DHCPV6_MSG_SOLICIT) { 366 odhcp6c_clear_state(STATE_IA_PD); 367 size_t n_prefixes; 368 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes); 369 n_prefixes /= sizeof(struct odhcp6c_request_prefix); 370 371 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix))); 372 373 for (size_t i = 0; i < n_prefixes; i++) { 374 struct dhcpv6_ia_hdr hdr_ia_pd = { 375 htons(DHCPV6_OPT_IA_PD), 376 htons(sizeof(hdr_ia_pd) - 4 + 377 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length), 378 request_prefixes[i].iaid, 0, 0 379 }; 380 struct dhcpv6_ia_prefix pref = { 381 .type = htons(DHCPV6_OPT_IA_PREFIX), 382 .len = htons(sizeof(pref) - 4), 383 .prefix = request_prefixes[i].length, 384 .addr = request_prefixes[i].addr 385 }; 386 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd)); 387 ia_pd_len += sizeof(hdr_ia_pd); 388 if (request_prefixes[i].length) { 389 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref)); 390 ia_pd_len += sizeof(pref); 391 } 392 } 393 } else { 394 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries); 395 ia_pd_entries /= sizeof(*e); 396 397 // we're too lazy to count our distinct IAIDs, 398 // so just allocate maximally needed space 399 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 + 400 sizeof(struct dhcpv6_ia_hdr))); 401 402 for (size_t i = 0; i < ia_pd_entries; ++i) { 403 uint32_t iaid = e[i].iaid; 404 405 // check if this is an unprocessed IAID and skip if not. 406 int new_iaid = 1; 407 for (int j = i-1; j >= 0; j--) { 408 if (e[j].iaid == iaid) { 409 new_iaid = 0; 410 break; 411 } 412 } 413 414 if (!new_iaid) 415 continue; 416 417 // construct header 418 struct dhcpv6_ia_hdr hdr_ia_pd = { 419 htons(DHCPV6_OPT_IA_PD), 420 htons(sizeof(hdr_ia_pd) - 4), 421 iaid, 0, 0 422 }; 423 424 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd)); 425 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len); 426 ia_pd_len += sizeof(hdr_ia_pd); 427 428 for (size_t j = i; j < ia_pd_entries; j++) { 429 if (e[j].iaid != iaid) 430 continue; 431 432 uint8_t ex_len = 0; 433 if (e[j].priority > 0) 434 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6; 435 436 struct dhcpv6_ia_prefix p = { 437 .type = htons(DHCPV6_OPT_IA_PREFIX), 438 .len = htons(sizeof(p) - 4U + ex_len), 439 .prefix = e[j].length, 440 .addr = e[j].target 441 }; 442 443 if (type == DHCPV6_MSG_REQUEST) { 444 p.preferred = htonl(e[j].preferred); 445 p.valid = htonl(e[j].valid); 446 } 447 448 memcpy(ia_pd + ia_pd_len, &p, sizeof(p)); 449 ia_pd_len += sizeof(p); 450 451 if (ex_len) { 452 ia_pd[ia_pd_len++] = 0; 453 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE; 454 ia_pd[ia_pd_len++] = 0; 455 ia_pd[ia_pd_len++] = ex_len - 4; 456 ia_pd[ia_pd_len++] = e[j].priority; 457 458 uint32_t excl = ntohl(e[j].router.s6_addr32[1]); 459 excl >>= (64 - e[j].priority); 460 excl <<= 8 - ((e[j].priority - e[j].length) % 8); 461 462 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8) 463 ia_pd[ia_pd_len + i] = excl & 0xff; 464 ia_pd_len += ex_len - 5; 465 } 466 467 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U); 468 } 469 } 470 } 471 472 // Build IA_NAs 473 size_t ia_na_entries, ia_na_len = 0; 474 void *ia_na = NULL; 475 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries); 476 ia_na_entries /= sizeof(*e); 477 478 struct dhcpv6_ia_hdr hdr_ia_na = { 479 htons(DHCPV6_OPT_IA_NA), 480 htons(sizeof(hdr_ia_na) - 4), 481 htonl(1), 0, 0 482 }; 483 484 struct dhcpv6_ia_addr pa[ia_na_entries]; 485 for (size_t i = 0; i < ia_na_entries; ++i) { 486 pa[i].type = htons(DHCPV6_OPT_IA_ADDR); 487 pa[i].len = htons(sizeof(pa[i]) - 4U); 488 pa[i].addr = e[i].target; 489 490 if (type == DHCPV6_MSG_REQUEST) { 491 pa[i].preferred = htonl(e[i].preferred); 492 pa[i].valid = htonl(e[i].valid); 493 } else { 494 pa[i].preferred = 0; 495 pa[i].valid = 0; 496 } 497 } 498 499 ia_na = pa; 500 ia_na_len = sizeof(pa); 501 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len); 502 503 // Reconfigure Accept 504 struct { 505 uint16_t type; 506 uint16_t length; 507 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0}; 508 509 // Option list 510 size_t opts_len; 511 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len); 512 513 // Option Request List 514 size_t oro_entries, oro_len = 0; 515 uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries); 516 517 oro_entries /= sizeof(*s_oro); 518 oro = alloca(oro_entries * sizeof(*oro)); 519 520 for (size_t i = 0; i < oro_entries; i++) { 521 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i])); 522 523 if (opt) { 524 if (!(opt->flags & OPT_ORO)) 525 continue; 526 527 if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT) 528 continue; 529 530 if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ) 531 continue; 532 533 if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ) 534 continue; 535 } 536 537 oro[oro_len++] = s_oro[i]; 538 } 539 oro_len *= sizeof(*oro); 540 541 // Prepare Header 542 struct { 543 uint8_t type; 544 uint8_t trid[3]; 545 uint16_t elapsed_type; 546 uint16_t elapsed_len; 547 uint16_t elapsed_value; 548 uint16_t oro_type; 549 uint16_t oro_len; 550 } hdr = { 551 type, {trid[0], trid[1], trid[2]}, 552 htons(DHCPV6_OPT_ELAPSED), htons(2), 553 htons((ecs > 0xffff) ? 0xffff : ecs), 554 htons(DHCPV6_OPT_ORO), htons(oro_len), 555 }; 556 557 struct iovec iov[IOV_TOTAL] = { 558 [IOV_HDR] = {&hdr, sizeof(hdr)}, 559 [IOV_ORO] = {oro, oro_len}, 560 [IOV_CL_ID] = {cl_id, cl_id_len}, 561 [IOV_SRV_ID] = {srv_id, srv_id_len}, 562 [IOV_OPTS] = { opts, opts_len }, 563 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)}, 564 [IOV_FQDN] = {&fqdn, fqdn_len}, 565 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)}, 566 [IOV_IA_NA] = {ia_na, ia_na_len}, 567 [IOV_IA_PD] = {ia_pd, ia_pd_len}, 568 }; 569 570 size_t cnt = IOV_TOTAL; 571 if (type == DHCPV6_MSG_INFO_REQ) 572 cnt = IOV_HDR_IA_NA; 573 574 // Disable IAs if not used 575 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0) 576 iov[IOV_HDR_IA_NA].iov_len = 0; 577 578 if (na_mode == IA_MODE_NONE) 579 iov[IOV_HDR_IA_NA].iov_len = 0; 580 581 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) || 582 !(client_options & DHCPV6_ACCEPT_RECONFIGURE)) 583 iov[IOV_RECONF_ACCEPT].iov_len = 0; 584 585 if (!(client_options & DHCPV6_CLIENT_FQDN)) 586 iov[IOV_FQDN].iov_len = 0; 587 588 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT), 589 0, ALL_DHCPV6_RELAYS, ifindex}; 590 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv), 591 .msg_iov = iov, .msg_iovlen = cnt}; 592 593 switch (type) { 594 case DHCPV6_MSG_REQUEST: 595 case DHCPV6_MSG_RENEW: 596 case DHCPV6_MSG_RELEASE: 597 case DHCPV6_MSG_DECLINE: 598 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) && 599 odhcp6c_addr_in_scope(&server_addr)) { 600 srv.sin6_addr = server_addr; 601 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr)) 602 srv.sin6_scope_id = 0; 603 } 604 break; 605 default: 606 break; 607 } 608 609 if (sendmsg(sock, &msg, 0) < 0) { 610 char in6_str[INET6_ADDRSTRLEN]; 611 612 syslog(LOG_ERR, "Failed to send %s message to %s (%s)", 613 dhcpv6_msg_to_str(type), 614 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr, 615 in6_str, sizeof(in6_str)), strerror(errno)); 616 } 617 } 618 619 static int64_t dhcpv6_rand_delay(int64_t time) 620 { 621 int random; 622 odhcp6c_random(&random, sizeof(random)); 623 624 return (time * ((int64_t)random % 1000LL)) / 10000LL; 625 } 626 627 int dhcpv6_request(enum dhcpv6_msg type) 628 { 629 uint8_t rc = 0; 630 uint64_t timeout = UINT32_MAX; 631 struct dhcpv6_retx *retx = &dhcpv6_retx[type]; 632 633 if (retx->delay) { 634 struct timespec ts = {0, 0}; 635 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000; 636 637 while (nanosleep(&ts, &ts) < 0 && errno == EINTR); 638 } 639 640 if (type == DHCPV6_MSG_UNKNOWN) 641 timeout = t1; 642 else if (type == DHCPV6_MSG_RENEW) 643 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0); 644 else if (type == DHCPV6_MSG_REBIND) 645 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0); 646 647 if (timeout == 0) 648 return -1; 649 650 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)", 651 retx->name, timeout, retx->max_rc); 652 653 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed; 654 655 // Generate transaction ID 656 uint8_t trid[3] = {0, 0, 0}; 657 if (type != DHCPV6_MSG_UNKNOWN) 658 odhcp6c_random(trid, sizeof(trid)); 659 660 ssize_t len = -1; 661 int64_t rto = 0; 662 663 do { 664 if (rto == 0) { 665 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000); 666 667 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2) 668 while (type == DHCPV6_MSG_SOLICIT && delay <= 0) 669 delay = dhcpv6_rand_delay(retx->init_timeo * 1000); 670 671 rto = (retx->init_timeo * 1000 + delay); 672 } else 673 rto = (2 * rto + dhcpv6_rand_delay(rto)); 674 675 if (retx->max_timeo && (rto >= retx->max_timeo * 1000)) 676 rto = retx->max_timeo * 1000 + 677 dhcpv6_rand_delay(retx->max_timeo * 1000); 678 679 // Calculate end for this round and elapsed time 680 uint64_t round_end = round_start + rto; 681 elapsed = round_start - start; 682 683 // Don't wait too long if timeout differs from infinite 684 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000)) 685 round_end = timeout * 1000 + start; 686 687 // Built and send package 688 switch (type) { 689 case DHCPV6_MSG_UNKNOWN: 690 break; 691 default: 692 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)", 693 retx->name, elapsed, rc); 694 // Fall through 695 case DHCPV6_MSG_SOLICIT: 696 case DHCPV6_MSG_INFO_REQ: 697 dhcpv6_send(type, trid, elapsed / 10); 698 rc++; 699 } 700 701 // Receive rounds 702 for (; len < 0 && (round_start < round_end); 703 round_start = odhcp6c_get_milli_time()) { 704 uint8_t buf[1536]; 705 union { 706 struct cmsghdr hdr; 707 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; 708 } cmsg_buf; 709 struct iovec iov = {buf, sizeof(buf)}; 710 struct sockaddr_in6 addr; 711 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr), 712 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf, 713 .msg_controllen = sizeof(cmsg_buf)}; 714 struct in6_pktinfo *pktinfo = NULL; 715 const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf; 716 717 // Check for pending signal 718 if (odhcp6c_signal_process()) 719 return -1; 720 721 // Set timeout for receiving 722 uint64_t t = round_end - round_start; 723 struct timeval tv = {t / 1000, (t % 1000) * 1000}; 724 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, 725 &tv, sizeof(tv)) < 0) 726 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)", 727 strerror(errno)); 728 729 // Receive cycle 730 len = recvmsg(sock, &msg, 0); 731 if (len < 0) 732 continue; 733 734 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; 735 ch = CMSG_NXTHDR(&msg, ch)) { 736 if (ch->cmsg_level == SOL_IPV6 && 737 ch->cmsg_type == IPV6_PKTINFO) { 738 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch); 739 break; 740 } 741 } 742 743 if (pktinfo == NULL) { 744 len = -1; 745 continue; 746 } 747 748 if (!dhcpv6_response_is_valid(buf, len, trid, 749 type, &pktinfo->ipi6_addr)) { 750 len = -1; 751 continue; 752 } 753 754 uint8_t *opt = &buf[4]; 755 uint8_t *opt_end = opt + len - 4; 756 757 round_start = odhcp6c_get_milli_time(); 758 elapsed = round_start - start; 759 syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms", 760 dhcpv6_msg_to_str(hdr->msg_type), elapsed); 761 762 if (retx->handler_reply) 763 len = retx->handler_reply(type, rc, opt, opt_end, &addr); 764 765 if (len > 0 && round_end - round_start > 1000) 766 round_end = 1000 + round_start; 767 } 768 769 // Allow 770 if (retx->handler_finish) 771 len = retx->handler_finish(); 772 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) && 773 (!retx->max_rc || rc < retx->max_rc)); 774 return len; 775 } 776 777 // Message validation checks according to RFC3315 chapter 15 778 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len, 779 const uint8_t transaction[3], enum dhcpv6_msg type, 780 const struct in6_addr *daddr) 781 { 782 const struct dhcpv6_header *rep = buf; 783 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id, 784 transaction, sizeof(rep->tr_id))) 785 return false; // Invalid reply 786 787 if (type == DHCPV6_MSG_SOLICIT) { 788 if (rep->msg_type != DHCPV6_MSG_ADVERT && 789 rep->msg_type != DHCPV6_MSG_REPLY) 790 return false; 791 792 } else if (type == DHCPV6_MSG_UNKNOWN) { 793 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF) 794 return false; 795 796 } else if (rep->msg_type != DHCPV6_MSG_REPLY) 797 return false; 798 799 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL, 800 rcmsg = DHCPV6_MSG_UNKNOWN; 801 uint16_t otype, olen = UINT16_MAX; 802 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false, 803 ia_present = false, options_valid = true; 804 805 size_t client_id_len, server_id_len; 806 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len); 807 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len); 808 809 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) { 810 if (otype == DHCPV6_OPT_CLIENTID) { 811 clientid_ok = (olen + 4U == client_id_len) && !memcmp( 812 &odata[-4], client_id, client_id_len); 813 } else if (otype == DHCPV6_OPT_SERVERID) { 814 if (server_id_len) 815 serverid_ok = (olen + 4U == server_id_len) && !memcmp( 816 &odata[-4], server_id, server_id_len); 817 else 818 serverid_ok = true; 819 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 + 820 sizeof(struct dhcpv6_auth_reconfigure)) { 821 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; 822 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2) 823 continue; 824 825 md5_ctx_t md5; 826 uint8_t serverhash[16], secretbytes[64]; 827 uint32_t hash[4]; 828 memcpy(serverhash, r->key, sizeof(serverhash)); 829 memset(r->key, 0, sizeof(r->key)); 830 831 memset(secretbytes, 0, sizeof(secretbytes)); 832 memcpy(secretbytes, reconf_key, sizeof(reconf_key)); 833 834 for (size_t i = 0; i < sizeof(secretbytes); ++i) 835 secretbytes[i] ^= 0x36; 836 837 md5_begin(&md5); 838 md5_hash(secretbytes, sizeof(secretbytes), &md5); 839 md5_hash(buf, len, &md5); 840 md5_end(hash, &md5); 841 842 for (size_t i = 0; i < sizeof(secretbytes); ++i) { 843 secretbytes[i] ^= 0x36; 844 secretbytes[i] ^= 0x5c; 845 } 846 847 md5_begin(&md5); 848 md5_hash(secretbytes, sizeof(secretbytes), &md5); 849 md5_hash(hash, 16, &md5); 850 md5_end(hash, &md5); 851 852 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash)); 853 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) { 854 rcmsg = odata[0]; 855 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) { 856 ia_present = true; 857 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr)) 858 options_valid = false; 859 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) || 860 (otype == DHCPV6_OPT_PD_EXCLUDE)) 861 // Options are not allowed on global level 862 options_valid = false; 863 } 864 865 if (!options_valid || ((odata + olen) > end)) 866 return false; 867 868 if (type == DHCPV6_MSG_INFO_REQ && ia_present) 869 return false; 870 871 if (rep->msg_type == DHCPV6_MSG_RECONF) { 872 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) || 873 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) || 874 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr)) 875 return false; 876 } 877 878 return clientid_ok && serverid_ok; 879 } 880 881 int dhcpv6_poll_reconfigure(void) 882 { 883 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN); 884 885 switch (ret) { 886 /* 887 * Only RENEW/REBIND/INFORMATION REQUEST 888 * message transmission can be requested 889 * by a RECONFIGURE 890 */ 891 case DHCPV6_MSG_RENEW: 892 case DHCPV6_MSG_REBIND: 893 case DHCPV6_MSG_INFO_REQ: 894 ret = dhcpv6_request(ret); 895 break; 896 897 default: 898 break; 899 } 900 901 return ret; 902 } 903 904 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc, 905 const void *opt, const void *end, _unused const struct sockaddr_in6 *from) 906 { 907 uint16_t otype, olen; 908 uint8_t *odata; 909 enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN; 910 911 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 912 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) { 913 switch (odata[0]) { 914 case DHCPV6_MSG_REBIND: 915 if (t2 != UINT32_MAX) 916 t2 = 0; 917 // Fall through 918 case DHCPV6_MSG_RENEW: 919 if (t1 != UINT32_MAX) 920 t1 = 0; 921 // Fall through 922 case DHCPV6_MSG_INFO_REQ: 923 msg = odata[0]; 924 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s", 925 dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF)); 926 break; 927 928 default: 929 break; 930 } 931 } 932 } 933 934 if (msg != DHCPV6_MSG_UNKNOWN) 935 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL); 936 937 return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg); 938 } 939 940 // Collect all advertised servers 941 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc, 942 const void *opt, const void *end, _unused const struct sockaddr_in6 *from) 943 { 944 uint16_t olen, otype; 945 uint8_t *odata, pref = 0; 946 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, 947 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT, 948 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0}; 949 bool have_na = false; 950 int have_pd = 0; 951 952 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 953 if (orig == DHCPV6_MSG_SOLICIT && 954 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) || 955 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) && 956 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) { 957 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]); 958 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr)); 959 } 960 961 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) { 962 memcpy(cand.duid, odata, olen); 963 cand.duid_len = olen; 964 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 && 965 cand.preference >= 0) { 966 cand.preference = pref = odata[0]; 967 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) { 968 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST)) 969 cand.server_addr = *(struct in6_addr *)odata; 970 971 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) { 972 cand.wants_reconfigure = true; 973 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) { 974 uint32_t sol_max_rt = ntohl_unaligned(odata); 975 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN && 976 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX) 977 cand.sol_max_rt = sol_max_rt; 978 979 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) { 980 uint32_t inf_max_rt = ntohl_unaligned(odata); 981 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN && 982 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX) 983 cand.inf_max_rt = inf_max_rt; 984 985 } else if (otype == DHCPV6_OPT_IA_PD && 986 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) { 987 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4]; 988 uint8_t *oend = odata + olen, *d; 989 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) { 990 if (otype == DHCPV6_OPT_IA_PREFIX && 991 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) { 992 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4]; 993 have_pd = p->prefix; 994 } 995 } 996 } else if (otype == DHCPV6_OPT_IA_NA && 997 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) { 998 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4]; 999 uint8_t *oend = odata + olen, *d; 1000 1001 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) { 1002 if (otype == DHCPV6_OPT_IA_ADDR && 1003 olen >= -4 + sizeof(struct dhcpv6_ia_addr)) 1004 have_na = true; 1005 } 1006 } 1007 } 1008 1009 if ((stateful_only_mode && !have_na && !have_pd) || 1010 (!have_na && na_mode == IA_MODE_FORCE) || 1011 (!have_pd && pd_mode == IA_MODE_FORCE)) { 1012 /* 1013 * RFC7083 states to process the SOL_MAX_RT and 1014 * INF_MAX_RT options even if the DHCPv6 server 1015 * did not propose any IA_NA and/or IA_PD 1016 */ 1017 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt; 1018 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt; 1019 return -1; 1020 } 1021 1022 if (na_mode != IA_MODE_NONE && !have_na) { 1023 cand.has_noaddravail = true; 1024 cand.preference -= 1000; 1025 } 1026 1027 if (pd_mode != IA_MODE_NONE) { 1028 if (have_pd) 1029 cand.preference += 2000 + (128 - have_pd); 1030 else 1031 cand.preference -= 2000; 1032 } 1033 1034 if (cand.duid_len > 0) { 1035 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len); 1036 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len); 1037 dhcpv6_add_server_cand(&cand); 1038 } 1039 1040 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1; 1041 } 1042 1043 static int dhcpv6_commit_advert(void) 1044 { 1045 return dhcpv6_promote_server_cand(); 1046 } 1047 1048 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc, 1049 const void *opt, const void *end, const struct sockaddr_in6 *from) 1050 { 1051 dhcpv6_handle_advert(orig, rc, opt, end, from); 1052 if (dhcpv6_commit_advert() < 0) 1053 return -1; 1054 1055 return dhcpv6_handle_reply(orig, rc, opt, end, from); 1056 } 1057 1058 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc, 1059 const void *opt, const void *end, const struct sockaddr_in6 *from) 1060 { 1061 uint8_t *odata; 1062 uint16_t otype, olen; 1063 uint32_t refresh = 86400; 1064 int ret = 1; 1065 unsigned int state_IAs; 1066 unsigned int updated_IAs = 0; 1067 bool handled_status_codes[_DHCPV6_Status_Max] = { false, }; 1068 1069 odhcp6c_expire(true); 1070 1071 if (orig == DHCPV6_MSG_UNKNOWN) { 1072 static time_t last_update = 0; 1073 time_t now = odhcp6c_get_milli_time() / 1000; 1074 1075 uint32_t elapsed = (last_update > 0) ? now - last_update : 0; 1076 last_update = now; 1077 1078 if (t1 != UINT32_MAX) 1079 t1 -= elapsed; 1080 1081 if (t2 != UINT32_MAX) 1082 t2 -= elapsed; 1083 1084 if (t3 != UINT32_MAX) 1085 t3 -= elapsed; 1086 1087 if (t1 < 0) 1088 t1 = 0; 1089 1090 if (t2 < 0) 1091 t2 = 0; 1092 1093 if (t3 < 0) 1094 t3 = 0; 1095 } 1096 1097 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) { 1098 // Delete NA and PD we have in the state from the Advert 1099 odhcp6c_clear_state(STATE_IA_NA); 1100 odhcp6c_clear_state(STATE_IA_PD); 1101 } 1102 1103 if (opt) { 1104 odhcp6c_clear_state(STATE_DNS); 1105 odhcp6c_clear_state(STATE_SEARCH); 1106 odhcp6c_clear_state(STATE_SNTP_IP); 1107 odhcp6c_clear_state(STATE_NTP_IP); 1108 odhcp6c_clear_state(STATE_NTP_FQDN); 1109 odhcp6c_clear_state(STATE_SIP_IP); 1110 odhcp6c_clear_state(STATE_SIP_FQDN); 1111 odhcp6c_clear_state(STATE_AFTR_NAME); 1112 odhcp6c_clear_state(STATE_CER); 1113 odhcp6c_clear_state(STATE_S46_MAPT); 1114 odhcp6c_clear_state(STATE_S46_MAPE); 1115 odhcp6c_clear_state(STATE_S46_LW); 1116 odhcp6c_clear_state(STATE_PASSTHRU); 1117 odhcp6c_clear_state(STATE_CUSTOM_OPTS); 1118 1119 // Parse and find all matching IAs 1120 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 1121 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype); 1122 1123 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) 1124 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) { 1125 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]); 1126 1127 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) || 1128 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD)) 1129 continue; 1130 1131 // Test ID 1132 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA) 1133 continue; 1134 1135 uint16_t code = DHCPV6_Success; 1136 uint16_t stype, slen; 1137 uint8_t *sdata; 1138 // Get and handle status code 1139 dhcpv6_for_each_option(&ia_hdr[1], odata + olen, 1140 stype, slen, sdata) { 1141 if (stype == DHCPV6_OPT_STATUS && slen >= 2) { 1142 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL; 1143 uint16_t mlen = (slen > 2) ? slen - 2 : 0; 1144 1145 code = ((int)sdata[0]) << 8 | ((int)sdata[1]); 1146 1147 if (code == DHCPV6_Success) 1148 continue; 1149 1150 dhcpv6_handle_ia_status_code(orig, ia_hdr, 1151 code, mdata, mlen, handled_status_codes, &ret); 1152 1153 if (ret > 0) 1154 return ret; 1155 1156 break; 1157 } 1158 } 1159 1160 if (code != DHCPV6_Success) 1161 continue; 1162 1163 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen); 1164 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) { 1165 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST)) 1166 server_addr = *(struct in6_addr *)odata; 1167 1168 } 1169 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) { 1170 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL; 1171 uint16_t mlen = (olen > 2) ? olen - 2 : 0; 1172 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]); 1173 1174 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret); 1175 } else if (otype == DHCPV6_OPT_DNS_SERVERS) { 1176 if (olen % 16 == 0) 1177 odhcp6c_add_state(STATE_DNS, odata, olen); 1178 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) 1179 odhcp6c_add_state(STATE_SEARCH, odata, olen); 1180 else if (otype == DHCPV6_OPT_SNTP_SERVERS) { 1181 if (olen % 16 == 0) 1182 odhcp6c_add_state(STATE_SNTP_IP, odata, olen); 1183 } else if (otype == DHCPV6_OPT_NTP_SERVER) { 1184 uint16_t stype, slen; 1185 uint8_t *sdata; 1186 // Test status and bail if error 1187 dhcpv6_for_each_option(odata, odata + olen, 1188 stype, slen, sdata) { 1189 if (slen == 16 && (stype == NTP_MC_ADDR || 1190 stype == NTP_SRV_ADDR)) 1191 odhcp6c_add_state(STATE_NTP_IP, 1192 sdata, slen); 1193 else if (slen > 0 && stype == NTP_SRV_FQDN) 1194 odhcp6c_add_state(STATE_NTP_FQDN, 1195 sdata, slen); 1196 } 1197 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) { 1198 if (olen == 16) 1199 odhcp6c_add_state(STATE_SIP_IP, odata, olen); 1200 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) 1201 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen); 1202 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) { 1203 refresh = ntohl_unaligned(odata); 1204 } else if (otype == DHCPV6_OPT_AUTH) { 1205 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) { 1206 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; 1207 if (r->protocol == 3 && r->algorithm == 1 && 1208 r->reconf_type == 1) 1209 memcpy(reconf_key, r->key, sizeof(r->key)); 1210 } 1211 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) { 1212 size_t cur_len; 1213 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len); 1214 if (cur_len == 0) 1215 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen); 1216 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) { 1217 uint32_t sol_max_rt = ntohl_unaligned(odata); 1218 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN && 1219 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX) 1220 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt; 1221 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) { 1222 uint32_t inf_max_rt = ntohl_unaligned(odata); 1223 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN && 1224 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX) 1225 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt; 1226 #ifdef EXT_CER_ID 1227 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 + 1228 sizeof(struct dhcpv6_cer_id)) { 1229 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4]; 1230 struct in6_addr any = IN6ADDR_ANY_INIT; 1231 if (memcmp(&cer_id->addr, &any, sizeof(any))) 1232 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any)); 1233 #endif 1234 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) { 1235 odhcp6c_add_state(STATE_S46_MAPT, odata, olen); 1236 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) { 1237 size_t mape_len; 1238 odhcp6c_get_state(STATE_S46_MAPE, &mape_len); 1239 if (mape_len == 0) 1240 odhcp6c_add_state(STATE_S46_MAPE, odata, olen); 1241 } else if (otype == DHCPV6_OPT_S46_CONT_LW) { 1242 odhcp6c_add_state(STATE_S46_LW, odata, olen); 1243 } else 1244 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4); 1245 1246 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU)) 1247 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4); 1248 } 1249 } 1250 1251 // Bail out if fatal status code was received 1252 if (ret <= 0) 1253 return ret; 1254 1255 switch (orig) { 1256 case DHCPV6_MSG_REQUEST: 1257 case DHCPV6_MSG_REBIND: 1258 case DHCPV6_MSG_RENEW: 1259 state_IAs = dhcpv6_calc_refresh_timers(); 1260 // In case there're no state IA entries 1261 // keep sending request/renew/rebind messages 1262 if (state_IAs == 0) { 1263 ret = 0; 1264 break; 1265 } 1266 1267 if (orig == DHCPV6_MSG_REQUEST) { 1268 // All server candidates can be cleared if not yet bound 1269 if (!odhcp6c_is_bound()) 1270 dhcpv6_clear_all_server_cand(); 1271 1272 odhcp6c_clear_state(STATE_SERVER_ADDR); 1273 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16); 1274 } else if (orig == DHCPV6_MSG_RENEW) { 1275 // Send further renews if T1 is not set and if 1276 // there're IAs which were not in the Reply message 1277 if (!t1 && state_IAs != updated_IAs) { 1278 if (updated_IAs) 1279 // Publish updates 1280 script_call("updated", 0, false); 1281 1282 /* 1283 * RFC8415 states following in §18.2.10.1 : 1284 * Sends a Renew/Rebind if any of the IAs are not in the Reply 1285 * message, but as this likely indicates that the server that 1286 * responded does not support that IA type, sending immediately is 1287 * unlikely to produce a different result. Therefore, the client 1288 * MUST rate-limit its transmissions (see Section 14.1) and MAY just 1289 * wait for the normal retransmission time (as if the Reply message 1290 * had not been received). The client continues to use other 1291 * bindings for which the server did return information 1292 */ 1293 ret = -1; 1294 } 1295 } else if (orig == DHCPV6_MSG_REBIND) { 1296 odhcp6c_clear_state(STATE_SERVER_ADDR); 1297 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16); 1298 1299 // Send further rebinds if T1 and T2 is not set and if 1300 // there're IAs which were not in the Reply message 1301 if (!t1 && !t2 && state_IAs != updated_IAs) { 1302 if (updated_IAs) 1303 // Publish updates 1304 script_call("updated", 0, false); 1305 1306 /* 1307 * RFC8415 states following in §18.2.10.1 : 1308 * Sends a Renew/Rebind if any of the IAs are not in the Reply 1309 * message, but as this likely indicates that the server that 1310 * responded does not support that IA type, sending immediately is 1311 * unlikely to produce a different result. Therefore, the client 1312 * MUST rate-limit its transmissions (see Section 14.1) and MAY just 1313 * wait for the normal retransmission time (as if the Reply message 1314 * had not been received). The client continues to use other 1315 * bindings for which the server did return information 1316 */ 1317 ret = -1; 1318 } 1319 } 1320 break; 1321 1322 case DHCPV6_MSG_INFO_REQ: 1323 // All server candidates can be cleared if not yet bound 1324 if (!odhcp6c_is_bound()) 1325 dhcpv6_clear_all_server_cand(); 1326 1327 t1 = refresh; 1328 break; 1329 1330 default: 1331 break; 1332 } 1333 1334 return ret; 1335 } 1336 1337 static unsigned int dhcpv6_parse_ia(void *opt, void *end) 1338 { 1339 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt; 1340 unsigned int updated_IAs = 0; 1341 uint32_t t1, t2; 1342 uint16_t otype, olen; 1343 uint8_t *odata; 1344 char buf[INET6_ADDRSTRLEN]; 1345 1346 t1 = ntohl(ia_hdr->t1); 1347 t2 = ntohl(ia_hdr->t2); 1348 1349 if (t1 > t2 && t1 > 0 && t2 > 0) 1350 return 0; 1351 1352 syslog(LOG_INFO, "%s %04x T1 %d T2 %d", ntohs(ia_hdr->type) == DHCPV6_OPT_IA_PD ? "IA_PD" : "IA_NA", ntohl(ia_hdr->iaid), t1, t2); 1353 1354 // Update address IA 1355 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) { 1356 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 1357 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0}; 1358 1359 entry.iaid = ia_hdr->iaid; 1360 1361 if (otype == DHCPV6_OPT_IA_PREFIX) { 1362 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4]; 1363 if (olen + 4U < sizeof(*prefix)) 1364 continue; 1365 1366 entry.valid = ntohl(prefix->valid); 1367 entry.preferred = ntohl(prefix->preferred); 1368 1369 if (entry.preferred > entry.valid) 1370 continue; 1371 1372 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX)); 1373 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX)); 1374 if (entry.t1 > entry.t2) 1375 entry.t1 = entry.t2; 1376 1377 entry.length = prefix->prefix; 1378 entry.target = prefix->addr; 1379 uint16_t stype, slen; 1380 uint8_t *sdata; 1381 1382 // Parse PD-exclude 1383 bool ok = true; 1384 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U, 1385 odata + olen, stype, slen, sdata) { 1386 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2) 1387 continue; 1388 1389 uint8_t elen = sdata[0]; 1390 if (elen > 64) 1391 elen = 64; 1392 1393 if (entry.length < 32 || elen <= entry.length) { 1394 ok = false; 1395 continue; 1396 } 1397 1398 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1; 1399 if (slen <= bytes) { 1400 ok = false; 1401 continue; 1402 } 1403 1404 uint32_t exclude = 0; 1405 do { 1406 exclude = exclude << 8 | sdata[bytes]; 1407 } while (--bytes); 1408 1409 exclude >>= 8 - ((elen - entry.length) % 8); 1410 exclude <<= 64 - elen; 1411 1412 // Abusing router & priority fields for exclusion 1413 entry.router = entry.target; 1414 entry.router.s6_addr32[1] |= htonl(exclude); 1415 entry.priority = elen; 1416 } 1417 1418 if (ok) { 1419 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0)) 1420 updated_IAs++; 1421 1422 syslog(LOG_INFO, "%s/%d preferred %d valid %d", 1423 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)), 1424 entry.length, entry.preferred , entry.valid); 1425 } 1426 1427 entry.priority = 0; 1428 memset(&entry.router, 0, sizeof(entry.router)); 1429 } else if (otype == DHCPV6_OPT_IA_ADDR) { 1430 struct dhcpv6_ia_addr *addr = (void*)&odata[-4]; 1431 if (olen + 4U < sizeof(*addr)) 1432 continue; 1433 1434 entry.preferred = ntohl(addr->preferred); 1435 entry.valid = ntohl(addr->valid); 1436 1437 if (entry.preferred > entry.valid) 1438 continue; 1439 1440 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX)); 1441 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX)); 1442 if (entry.t1 > entry.t2) 1443 entry.t1 = entry.t2; 1444 1445 entry.length = 128; 1446 entry.target = addr->addr; 1447 1448 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0)) 1449 updated_IAs++; 1450 1451 syslog(LOG_INFO, "%s preferred %d valid %d", 1452 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)), 1453 entry.preferred , entry.valid); 1454 } 1455 } 1456 1457 return updated_IAs; 1458 } 1459 1460 static unsigned int dhcpv6_calc_refresh_timers(void) 1461 { 1462 struct odhcp6c_entry *e; 1463 size_t ia_na_entries, ia_pd_entries, i; 1464 size_t invalid_entries = 0; 1465 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0; 1466 1467 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries); 1468 ia_na_entries /= sizeof(*e); 1469 1470 for (i = 0; i < ia_na_entries; i++) { 1471 /* Exclude invalid IA_NA entries */ 1472 if (!e[i].valid) { 1473 invalid_entries++; 1474 continue; 1475 } 1476 1477 if (e[i].t1 < l_t1) 1478 l_t1 = e[i].t1; 1479 1480 if (e[i].t2 < l_t2) 1481 l_t2 = e[i].t2; 1482 1483 if (e[i].valid > l_t3) 1484 l_t3 = e[i].valid; 1485 } 1486 1487 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries); 1488 ia_pd_entries /= sizeof(*e); 1489 1490 for (i = 0; i < ia_pd_entries; i++) { 1491 /* Exclude invalid IA_PD entries */ 1492 if (!e[i].valid) { 1493 invalid_entries++; 1494 continue; 1495 } 1496 1497 if (e[i].t1 < l_t1) 1498 l_t1 = e[i].t1; 1499 1500 if (e[i].t2 < l_t2) 1501 l_t2 = e[i].t2; 1502 1503 if (e[i].valid > l_t3) 1504 l_t3 = e[i].valid; 1505 } 1506 1507 if (ia_pd_entries + ia_na_entries - invalid_entries) { 1508 t1 = l_t1; 1509 t2 = l_t2; 1510 t3 = l_t3; 1511 1512 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3); 1513 } 1514 1515 return (unsigned int)(ia_pd_entries + ia_na_entries); 1516 } 1517 1518 static void dhcpv6_log_status_code(const uint16_t code, const char *scope, 1519 const void *status_msg, int len) 1520 { 1521 const char *src = status_msg; 1522 char buf[len + 3]; 1523 char *dst = buf; 1524 1525 if (len) { 1526 *dst++ = '('; 1527 while (len--) { 1528 *dst = isprint((unsigned char)*src) ? *src : '?'; 1529 src++; 1530 dst++; 1531 } 1532 *dst++ = ')'; 1533 } 1534 1535 *dst = 0; 1536 1537 syslog(LOG_WARNING, "Server returned %s status '%s %s'", 1538 scope, dhcpv6_status_code_to_str(code), buf); 1539 } 1540 1541 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig, 1542 const uint16_t code, const void *status_msg, const int len, 1543 int *ret) 1544 { 1545 dhcpv6_log_status_code(code, "message", status_msg, len); 1546 1547 switch (code) { 1548 case DHCPV6_UnspecFail: 1549 // Generic failure 1550 *ret = 0; 1551 break; 1552 1553 case DHCPV6_UseMulticast: 1554 switch(orig) { 1555 case DHCPV6_MSG_REQUEST: 1556 case DHCPV6_MSG_RENEW: 1557 case DHCPV6_MSG_RELEASE: 1558 case DHCPV6_MSG_DECLINE: 1559 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8 1560 server_addr = in6addr_any; 1561 *ret = 0; 1562 break; 1563 default: 1564 break; 1565 } 1566 break; 1567 1568 case DHCPV6_NoAddrsAvail: 1569 case DHCPV6_NoPrefixAvail: 1570 if (orig == DHCPV6_MSG_REQUEST) 1571 *ret = 0; // Failure 1572 break; 1573 1574 default: 1575 break; 1576 } 1577 } 1578 1579 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig, 1580 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code, 1581 const void *status_msg, const int len, 1582 bool handled_status_codes[_DHCPV6_Status_Max], int *ret) 1583 { 1584 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ? 1585 "IA_NA" : "IA_PD", status_msg, len); 1586 1587 switch (code) { 1588 case DHCPV6_NoBinding: 1589 switch (orig) { 1590 case DHCPV6_MSG_RENEW: 1591 case DHCPV6_MSG_REBIND: 1592 if ((*ret > 0) && !handled_status_codes[code]) 1593 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST); 1594 break; 1595 1596 default: 1597 break; 1598 } 1599 break; 1600 1601 default: 1602 *ret = 0; 1603 break; 1604 } 1605 } 1606 1607 // Note this always takes ownership of cand->ia_na and cand->ia_pd 1608 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand) 1609 { 1610 size_t cand_len, i; 1611 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1612 1613 // Remove identical duid server candidate 1614 for (i = 0; i < cand_len / sizeof(*c); ++i) { 1615 if (cand->duid_len == c[i].duid_len && 1616 !memcmp(cand->duid, c[i].duid, cand->duid_len)) { 1617 free(c[i].ia_na); 1618 free(c[i].ia_pd); 1619 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c)); 1620 break; 1621 } 1622 } 1623 1624 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1625 i < cand_len / sizeof(*c); ++i) { 1626 if (c[i].preference < cand->preference) 1627 break; 1628 } 1629 1630 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) { 1631 free(cand->ia_na); 1632 free(cand->ia_pd); 1633 } 1634 } 1635 1636 static void dhcpv6_clear_all_server_cand(void) 1637 { 1638 size_t cand_len, i; 1639 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1640 1641 // Server candidates need deep delete for IA_NA/IA_PD 1642 for (i = 0; i < cand_len / sizeof(*c); ++i) { 1643 free(c[i].ia_na); 1644 free(c[i].ia_pd); 1645 } 1646 odhcp6c_clear_state(STATE_SERVER_CAND); 1647 } 1648 1649 int dhcpv6_promote_server_cand(void) 1650 { 1651 size_t cand_len; 1652 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1653 uint16_t hdr[2]; 1654 int ret = DHCPV6_STATELESS; 1655 1656 // Clear lingering candidate state info 1657 odhcp6c_clear_state(STATE_SERVER_ID); 1658 odhcp6c_clear_state(STATE_IA_NA); 1659 odhcp6c_clear_state(STATE_IA_PD); 1660 1661 if (!cand_len) 1662 return -1; 1663 1664 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) { 1665 na_mode = IA_MODE_NONE; 1666 1667 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt; 1668 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt; 1669 1670 return dhcpv6_request(DHCPV6_MSG_SOLICIT); 1671 } 1672 1673 hdr[0] = htons(DHCPV6_OPT_SERVERID); 1674 hdr[1] = htons(cand->duid_len); 1675 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr)); 1676 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len); 1677 accept_reconfig = cand->wants_reconfigure; 1678 1679 if (cand->ia_na_len) { 1680 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len); 1681 free(cand->ia_na); 1682 if (na_mode != IA_MODE_NONE) 1683 ret = DHCPV6_STATEFUL; 1684 } 1685 1686 if (cand->ia_pd_len) { 1687 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len); 1688 free(cand->ia_pd); 1689 if (pd_mode != IA_MODE_NONE) 1690 ret = DHCPV6_STATEFUL; 1691 } 1692 1693 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt; 1694 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt; 1695 1696 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand)); 1697 1698 return ret; 1699 } 1700
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