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_AFTR_NAME), 260 htons(DHCPV6_OPT_PD_EXCLUDE), 261 #ifdef EXT_CER_ID 262 htons(DHCPV6_OPT_CER_ID), 263 #endif 264 htons(DHCPV6_OPT_S46_CONT_MAPE), 265 htons(DHCPV6_OPT_S46_CONT_MAPT), 266 htons(DHCPV6_OPT_S46_CONT_LW), 267 }; 268 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro)); 269 } 270 // Required oro 271 uint16_t req_oro[] = { 272 htons(DHCPV6_OPT_INF_MAX_RT), 273 htons(DHCPV6_OPT_SOL_MAX_RT), 274 htons(DHCPV6_OPT_INFO_REFRESH), 275 }; 276 odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro)); 277 278 // Configure IPv6-options 279 int val = 1; 280 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0) 281 goto failure; 282 283 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0) 284 goto failure; 285 286 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0) 287 goto failure; 288 289 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0) 290 goto failure; 291 292 if (setsockopt(sock, SOL_SOCKET, SO_PRIORITY, &sk_prio, sizeof(sk_prio)) < 0) 293 goto failure; 294 295 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6, 296 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 }; 297 298 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0) 299 goto failure; 300 301 return 0; 302 303 failure: 304 if (sock >= 0) 305 close(sock); 306 307 return -1; 308 } 309 310 enum { 311 IOV_HDR=0, 312 IOV_ORO, 313 IOV_CL_ID, 314 IOV_SRV_ID, 315 IOV_OPTS, 316 IOV_RECONF_ACCEPT, 317 IOV_FQDN, 318 IOV_HDR_IA_NA, 319 IOV_IA_NA, 320 IOV_IA_PD, 321 IOV_TOTAL 322 }; 323 324 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd, bool stateful_only) 325 { 326 int mode = DHCPV6_UNKNOWN; 327 328 na_mode = na; 329 pd_mode = pd; 330 stateful_only_mode = stateful_only; 331 332 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) 333 mode = DHCPV6_STATELESS; 334 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE) 335 mode = DHCPV6_STATEFUL; 336 337 return mode; 338 } 339 340 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs) 341 { 342 // Build FQDN 343 char fqdn_buf[256]; 344 gethostname(fqdn_buf, sizeof(fqdn_buf)); 345 struct { 346 uint16_t type; 347 uint16_t len; 348 uint8_t flags; 349 uint8_t data[256]; 350 } fqdn; 351 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data, 352 sizeof(fqdn.data), NULL, NULL); 353 fqdn.type = htons(DHCPV6_OPT_FQDN); 354 fqdn.len = htons(fqdn_len - 4); 355 fqdn.flags = 0; 356 357 // Build Client ID 358 size_t cl_id_len; 359 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len); 360 361 // Get Server ID 362 size_t srv_id_len; 363 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len); 364 365 // Build IA_PDs 366 size_t ia_pd_entries = 0, ia_pd_len = 0; 367 uint8_t *ia_pd; 368 369 if (type == DHCPV6_MSG_SOLICIT) { 370 odhcp6c_clear_state(STATE_IA_PD); 371 size_t n_prefixes; 372 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes); 373 n_prefixes /= sizeof(struct odhcp6c_request_prefix); 374 375 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix))); 376 377 for (size_t i = 0; i < n_prefixes; i++) { 378 struct dhcpv6_ia_hdr hdr_ia_pd = { 379 htons(DHCPV6_OPT_IA_PD), 380 htons(sizeof(hdr_ia_pd) - 4 + 381 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length), 382 request_prefixes[i].iaid, 0, 0 383 }; 384 struct dhcpv6_ia_prefix pref = { 385 .type = htons(DHCPV6_OPT_IA_PREFIX), 386 .len = htons(sizeof(pref) - 4), 387 .prefix = request_prefixes[i].length 388 }; 389 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd)); 390 ia_pd_len += sizeof(hdr_ia_pd); 391 if (request_prefixes[i].length) { 392 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref)); 393 ia_pd_len += sizeof(pref); 394 } 395 } 396 } else { 397 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries); 398 ia_pd_entries /= sizeof(*e); 399 400 // we're too lazy to count our distinct IAIDs, 401 // so just allocate maximally needed space 402 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 + 403 sizeof(struct dhcpv6_ia_hdr))); 404 405 for (size_t i = 0; i < ia_pd_entries; ++i) { 406 uint32_t iaid = e[i].iaid; 407 408 // check if this is an unprocessed IAID and skip if not. 409 int new_iaid = 1; 410 for (int j = i-1; j >= 0; j--) { 411 if (e[j].iaid == iaid) { 412 new_iaid = 0; 413 break; 414 } 415 } 416 417 if (!new_iaid) 418 continue; 419 420 // construct header 421 struct dhcpv6_ia_hdr hdr_ia_pd = { 422 htons(DHCPV6_OPT_IA_PD), 423 htons(sizeof(hdr_ia_pd) - 4), 424 iaid, 0, 0 425 }; 426 427 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd)); 428 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len); 429 ia_pd_len += sizeof(hdr_ia_pd); 430 431 for (size_t j = i; j < ia_pd_entries; j++) { 432 if (e[j].iaid != iaid) 433 continue; 434 435 uint8_t ex_len = 0; 436 if (e[j].priority > 0) 437 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6; 438 439 struct dhcpv6_ia_prefix p = { 440 .type = htons(DHCPV6_OPT_IA_PREFIX), 441 .len = htons(sizeof(p) - 4U + ex_len), 442 .prefix = e[j].length, 443 .addr = e[j].target 444 }; 445 446 if (type == DHCPV6_MSG_REQUEST) { 447 p.preferred = htonl(e[j].preferred); 448 p.valid = htonl(e[j].valid); 449 } 450 451 memcpy(ia_pd + ia_pd_len, &p, sizeof(p)); 452 ia_pd_len += sizeof(p); 453 454 if (ex_len) { 455 ia_pd[ia_pd_len++] = 0; 456 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE; 457 ia_pd[ia_pd_len++] = 0; 458 ia_pd[ia_pd_len++] = ex_len - 4; 459 ia_pd[ia_pd_len++] = e[j].priority; 460 461 uint32_t excl = ntohl(e[j].router.s6_addr32[1]); 462 excl >>= (64 - e[j].priority); 463 excl <<= 8 - ((e[j].priority - e[j].length) % 8); 464 465 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8) 466 ia_pd[ia_pd_len + i] = excl & 0xff; 467 ia_pd_len += ex_len - 5; 468 } 469 470 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U); 471 } 472 } 473 } 474 475 // Build IA_NAs 476 size_t ia_na_entries, ia_na_len = 0; 477 void *ia_na = NULL; 478 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries); 479 ia_na_entries /= sizeof(*e); 480 481 struct dhcpv6_ia_hdr hdr_ia_na = { 482 htons(DHCPV6_OPT_IA_NA), 483 htons(sizeof(hdr_ia_na) - 4), 484 htonl(1), 0, 0 485 }; 486 487 struct dhcpv6_ia_addr pa[ia_na_entries]; 488 for (size_t i = 0; i < ia_na_entries; ++i) { 489 pa[i].type = htons(DHCPV6_OPT_IA_ADDR); 490 pa[i].len = htons(sizeof(pa[i]) - 4U); 491 pa[i].addr = e[i].target; 492 493 if (type == DHCPV6_MSG_REQUEST) { 494 pa[i].preferred = htonl(e[i].preferred); 495 pa[i].valid = htonl(e[i].valid); 496 } else { 497 pa[i].preferred = 0; 498 pa[i].valid = 0; 499 } 500 } 501 502 ia_na = pa; 503 ia_na_len = sizeof(pa); 504 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len); 505 506 // Reconfigure Accept 507 struct { 508 uint16_t type; 509 uint16_t length; 510 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0}; 511 512 // Option list 513 size_t opts_len; 514 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len); 515 516 // Option Request List 517 size_t oro_entries, oro_len = 0; 518 uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries); 519 520 oro_entries /= sizeof(*s_oro); 521 oro = alloca(oro_entries * sizeof(*oro)); 522 523 for (size_t i = 0; i < oro_entries; i++) { 524 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i])); 525 526 if (opt) { 527 if (!(opt->flags & OPT_ORO)) 528 continue; 529 530 if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT) 531 continue; 532 533 if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ) 534 continue; 535 536 if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ) 537 continue; 538 } 539 540 oro[oro_len++] = s_oro[i]; 541 } 542 oro_len *= sizeof(*oro); 543 544 // Prepare Header 545 struct { 546 uint8_t type; 547 uint8_t trid[3]; 548 uint16_t elapsed_type; 549 uint16_t elapsed_len; 550 uint16_t elapsed_value; 551 uint16_t oro_type; 552 uint16_t oro_len; 553 } hdr = { 554 type, {trid[0], trid[1], trid[2]}, 555 htons(DHCPV6_OPT_ELAPSED), htons(2), 556 htons((ecs > 0xffff) ? 0xffff : ecs), 557 htons(DHCPV6_OPT_ORO), htons(oro_len), 558 }; 559 560 struct iovec iov[IOV_TOTAL] = { 561 [IOV_HDR] = {&hdr, sizeof(hdr)}, 562 [IOV_ORO] = {oro, oro_len}, 563 [IOV_CL_ID] = {cl_id, cl_id_len}, 564 [IOV_SRV_ID] = {srv_id, srv_id_len}, 565 [IOV_OPTS] = { opts, opts_len }, 566 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)}, 567 [IOV_FQDN] = {&fqdn, fqdn_len}, 568 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)}, 569 [IOV_IA_NA] = {ia_na, ia_na_len}, 570 [IOV_IA_PD] = {ia_pd, ia_pd_len}, 571 }; 572 573 size_t cnt = IOV_TOTAL; 574 if (type == DHCPV6_MSG_INFO_REQ) 575 cnt = IOV_HDR_IA_NA; 576 577 // Disable IAs if not used 578 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0) 579 iov[IOV_HDR_IA_NA].iov_len = 0; 580 581 if (na_mode == IA_MODE_NONE) 582 iov[IOV_HDR_IA_NA].iov_len = 0; 583 584 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) || 585 !(client_options & DHCPV6_ACCEPT_RECONFIGURE)) 586 iov[IOV_RECONF_ACCEPT].iov_len = 0; 587 588 if (!(client_options & DHCPV6_CLIENT_FQDN)) 589 iov[IOV_FQDN].iov_len = 0; 590 591 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT), 592 0, ALL_DHCPV6_RELAYS, ifindex}; 593 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv), 594 .msg_iov = iov, .msg_iovlen = cnt}; 595 596 switch (type) { 597 case DHCPV6_MSG_REQUEST: 598 case DHCPV6_MSG_RENEW: 599 case DHCPV6_MSG_RELEASE: 600 case DHCPV6_MSG_DECLINE: 601 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) && 602 odhcp6c_addr_in_scope(&server_addr)) { 603 srv.sin6_addr = server_addr; 604 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr)) 605 srv.sin6_scope_id = 0; 606 } 607 break; 608 default: 609 break; 610 } 611 612 if (sendmsg(sock, &msg, 0) < 0) { 613 char in6_str[INET6_ADDRSTRLEN]; 614 615 syslog(LOG_ERR, "Failed to send %s message to %s (%s)", 616 dhcpv6_msg_to_str(type), 617 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr, 618 in6_str, sizeof(in6_str)), strerror(errno)); 619 } 620 } 621 622 static int64_t dhcpv6_rand_delay(int64_t time) 623 { 624 int random; 625 odhcp6c_random(&random, sizeof(random)); 626 627 return (time * ((int64_t)random % 1000LL)) / 10000LL; 628 } 629 630 int dhcpv6_request(enum dhcpv6_msg type) 631 { 632 uint8_t rc = 0; 633 uint64_t timeout = UINT32_MAX; 634 struct dhcpv6_retx *retx = &dhcpv6_retx[type]; 635 636 if (retx->delay) { 637 struct timespec ts = {0, 0}; 638 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000; 639 640 while (nanosleep(&ts, &ts) < 0 && errno == EINTR); 641 } 642 643 if (type == DHCPV6_MSG_UNKNOWN) 644 timeout = t1; 645 else if (type == DHCPV6_MSG_RENEW) 646 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0); 647 else if (type == DHCPV6_MSG_REBIND) 648 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0); 649 650 if (timeout == 0) 651 return -1; 652 653 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)", 654 retx->name, timeout, retx->max_rc); 655 656 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed; 657 658 // Generate transaction ID 659 uint8_t trid[3] = {0, 0, 0}; 660 if (type != DHCPV6_MSG_UNKNOWN) 661 odhcp6c_random(trid, sizeof(trid)); 662 663 ssize_t len = -1; 664 int64_t rto = 0; 665 666 do { 667 if (rto == 0) { 668 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000); 669 670 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2) 671 while (type == DHCPV6_MSG_SOLICIT && delay <= 0) 672 delay = dhcpv6_rand_delay(retx->init_timeo * 1000); 673 674 rto = (retx->init_timeo * 1000 + delay); 675 } else 676 rto = (2 * rto + dhcpv6_rand_delay(rto)); 677 678 if (retx->max_timeo && (rto >= retx->max_timeo * 1000)) 679 rto = retx->max_timeo * 1000 + 680 dhcpv6_rand_delay(retx->max_timeo * 1000); 681 682 // Calculate end for this round and elapsed time 683 uint64_t round_end = round_start + rto; 684 elapsed = round_start - start; 685 686 // Don't wait too long if timeout differs from infinite 687 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000)) 688 round_end = timeout * 1000 + start; 689 690 // Built and send package 691 switch (type) { 692 case DHCPV6_MSG_UNKNOWN: 693 break; 694 default: 695 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)", 696 retx->name, elapsed, rc); 697 // Fall through 698 case DHCPV6_MSG_SOLICIT: 699 case DHCPV6_MSG_INFO_REQ: 700 dhcpv6_send(type, trid, elapsed / 10); 701 rc++; 702 } 703 704 // Receive rounds 705 for (; len < 0 && (round_start < round_end); 706 round_start = odhcp6c_get_milli_time()) { 707 uint8_t buf[1536]; 708 union { 709 struct cmsghdr hdr; 710 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]; 711 } cmsg_buf; 712 struct iovec iov = {buf, sizeof(buf)}; 713 struct sockaddr_in6 addr; 714 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr), 715 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf, 716 .msg_controllen = sizeof(cmsg_buf)}; 717 struct in6_pktinfo *pktinfo = NULL; 718 const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf; 719 720 // Check for pending signal 721 if (odhcp6c_signal_process()) 722 return -1; 723 724 // Set timeout for receiving 725 uint64_t t = round_end - round_start; 726 struct timeval tv = {t / 1000, (t % 1000) * 1000}; 727 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, 728 &tv, sizeof(tv)) < 0) 729 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)", 730 strerror(errno)); 731 732 // Receive cycle 733 len = recvmsg(sock, &msg, 0); 734 if (len < 0) 735 continue; 736 737 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; 738 ch = CMSG_NXTHDR(&msg, ch)) { 739 if (ch->cmsg_level == SOL_IPV6 && 740 ch->cmsg_type == IPV6_PKTINFO) { 741 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch); 742 break; 743 } 744 } 745 746 if (pktinfo == NULL) { 747 len = -1; 748 continue; 749 } 750 751 if (!dhcpv6_response_is_valid(buf, len, trid, 752 type, &pktinfo->ipi6_addr)) { 753 len = -1; 754 continue; 755 } 756 757 uint8_t *opt = &buf[4]; 758 uint8_t *opt_end = opt + len - 4; 759 760 round_start = odhcp6c_get_milli_time(); 761 elapsed = round_start - start; 762 syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms", 763 dhcpv6_msg_to_str(hdr->msg_type), elapsed); 764 765 if (retx->handler_reply) 766 len = retx->handler_reply(type, rc, opt, opt_end, &addr); 767 768 if (len > 0 && round_end - round_start > 1000) 769 round_end = 1000 + round_start; 770 } 771 772 // Allow 773 if (retx->handler_finish) 774 len = retx->handler_finish(); 775 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) && 776 (!retx->max_rc || rc < retx->max_rc)); 777 return len; 778 } 779 780 // Message validation checks according to RFC3315 chapter 15 781 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len, 782 const uint8_t transaction[3], enum dhcpv6_msg type, 783 const struct in6_addr *daddr) 784 { 785 const struct dhcpv6_header *rep = buf; 786 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id, 787 transaction, sizeof(rep->tr_id))) 788 return false; // Invalid reply 789 790 if (type == DHCPV6_MSG_SOLICIT) { 791 if (rep->msg_type != DHCPV6_MSG_ADVERT && 792 rep->msg_type != DHCPV6_MSG_REPLY) 793 return false; 794 795 } else if (type == DHCPV6_MSG_UNKNOWN) { 796 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF) 797 return false; 798 799 } else if (rep->msg_type != DHCPV6_MSG_REPLY) 800 return false; 801 802 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL, 803 rcmsg = DHCPV6_MSG_UNKNOWN; 804 uint16_t otype, olen = UINT16_MAX; 805 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false, 806 ia_present = false, options_valid = true; 807 808 size_t client_id_len, server_id_len; 809 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len); 810 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len); 811 812 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) { 813 if (otype == DHCPV6_OPT_CLIENTID) { 814 clientid_ok = (olen + 4U == client_id_len) && !memcmp( 815 &odata[-4], client_id, client_id_len); 816 } else if (otype == DHCPV6_OPT_SERVERID) { 817 if (server_id_len) 818 serverid_ok = (olen + 4U == server_id_len) && !memcmp( 819 &odata[-4], server_id, server_id_len); 820 else 821 serverid_ok = true; 822 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 + 823 sizeof(struct dhcpv6_auth_reconfigure)) { 824 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; 825 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2) 826 continue; 827 828 md5_ctx_t md5; 829 uint8_t serverhash[16], secretbytes[64]; 830 uint32_t hash[4]; 831 memcpy(serverhash, r->key, sizeof(serverhash)); 832 memset(r->key, 0, sizeof(r->key)); 833 834 memset(secretbytes, 0, sizeof(secretbytes)); 835 memcpy(secretbytes, reconf_key, sizeof(reconf_key)); 836 837 for (size_t i = 0; i < sizeof(secretbytes); ++i) 838 secretbytes[i] ^= 0x36; 839 840 md5_begin(&md5); 841 md5_hash(secretbytes, sizeof(secretbytes), &md5); 842 md5_hash(buf, len, &md5); 843 md5_end(hash, &md5); 844 845 for (size_t i = 0; i < sizeof(secretbytes); ++i) { 846 secretbytes[i] ^= 0x36; 847 secretbytes[i] ^= 0x5c; 848 } 849 850 md5_begin(&md5); 851 md5_hash(secretbytes, sizeof(secretbytes), &md5); 852 md5_hash(hash, 16, &md5); 853 md5_end(hash, &md5); 854 855 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash)); 856 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) { 857 rcmsg = odata[0]; 858 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) { 859 ia_present = true; 860 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr)) 861 options_valid = false; 862 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) || 863 (otype == DHCPV6_OPT_PD_EXCLUDE)) 864 // Options are not allowed on global level 865 options_valid = false; 866 } 867 868 if (!options_valid || ((odata + olen) > end)) 869 return false; 870 871 if (type == DHCPV6_MSG_INFO_REQ && ia_present) 872 return false; 873 874 if (rep->msg_type == DHCPV6_MSG_RECONF) { 875 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) || 876 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) || 877 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr)) 878 return false; 879 } 880 881 return clientid_ok && serverid_ok; 882 } 883 884 int dhcpv6_poll_reconfigure(void) 885 { 886 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN); 887 888 switch (ret) { 889 /* 890 * Only RENEW/REBIND/INFORMATION REQUEST 891 * message transmission can be requested 892 * by a RECONFIGURE 893 */ 894 case DHCPV6_MSG_RENEW: 895 case DHCPV6_MSG_REBIND: 896 case DHCPV6_MSG_INFO_REQ: 897 ret = dhcpv6_request(ret); 898 break; 899 900 default: 901 break; 902 } 903 904 return ret; 905 } 906 907 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc, 908 const void *opt, const void *end, _unused const struct sockaddr_in6 *from) 909 { 910 uint16_t otype, olen; 911 uint8_t *odata; 912 enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN; 913 914 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 915 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) { 916 switch (odata[0]) { 917 case DHCPV6_MSG_REBIND: 918 if (t2 != UINT32_MAX) 919 t2 = 0; 920 // Fall through 921 case DHCPV6_MSG_RENEW: 922 if (t1 != UINT32_MAX) 923 t1 = 0; 924 // Fall through 925 case DHCPV6_MSG_INFO_REQ: 926 msg = odata[0]; 927 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s", 928 dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF)); 929 break; 930 931 default: 932 break; 933 } 934 } 935 } 936 937 if (msg != DHCPV6_MSG_UNKNOWN) 938 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL); 939 940 return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg); 941 } 942 943 // Collect all advertised servers 944 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc, 945 const void *opt, const void *end, _unused const struct sockaddr_in6 *from) 946 { 947 uint16_t olen, otype; 948 uint8_t *odata, pref = 0; 949 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, 950 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT, 951 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0}; 952 bool have_na = false; 953 int have_pd = 0; 954 955 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 956 if (orig == DHCPV6_MSG_SOLICIT && 957 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) || 958 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) && 959 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) { 960 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]); 961 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr)); 962 } 963 964 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) { 965 memcpy(cand.duid, odata, olen); 966 cand.duid_len = olen; 967 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 && 968 cand.preference >= 0) { 969 cand.preference = pref = odata[0]; 970 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) { 971 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST)) 972 cand.server_addr = *(struct in6_addr *)odata; 973 974 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) { 975 cand.wants_reconfigure = true; 976 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) { 977 uint32_t sol_max_rt = ntohl_unaligned(odata); 978 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN && 979 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX) 980 cand.sol_max_rt = sol_max_rt; 981 982 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) { 983 uint32_t inf_max_rt = ntohl_unaligned(odata); 984 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN && 985 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX) 986 cand.inf_max_rt = inf_max_rt; 987 988 } else if (otype == DHCPV6_OPT_IA_PD && 989 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) { 990 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4]; 991 uint8_t *oend = odata + olen, *d; 992 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) { 993 if (otype == DHCPV6_OPT_IA_PREFIX && 994 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) { 995 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4]; 996 have_pd = p->prefix; 997 } 998 } 999 } else if (otype == DHCPV6_OPT_IA_NA && 1000 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) { 1001 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4]; 1002 uint8_t *oend = odata + olen, *d; 1003 1004 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) { 1005 if (otype == DHCPV6_OPT_IA_ADDR && 1006 olen >= -4 + sizeof(struct dhcpv6_ia_addr)) 1007 have_na = true; 1008 } 1009 } 1010 } 1011 1012 if ((stateful_only_mode && !have_na && !have_pd) || 1013 (!have_na && na_mode == IA_MODE_FORCE) || 1014 (!have_pd && pd_mode == IA_MODE_FORCE)) { 1015 /* 1016 * RFC7083 states to process the SOL_MAX_RT and 1017 * INF_MAX_RT options even if the DHCPv6 server 1018 * did not propose any IA_NA and/or IA_PD 1019 */ 1020 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt; 1021 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt; 1022 return -1; 1023 } 1024 1025 if (na_mode != IA_MODE_NONE && !have_na) { 1026 cand.has_noaddravail = true; 1027 cand.preference -= 1000; 1028 } 1029 1030 if (pd_mode != IA_MODE_NONE) { 1031 if (have_pd) 1032 cand.preference += 2000 + (128 - have_pd); 1033 else 1034 cand.preference -= 2000; 1035 } 1036 1037 if (cand.duid_len > 0) { 1038 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len); 1039 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len); 1040 dhcpv6_add_server_cand(&cand); 1041 } 1042 1043 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1; 1044 } 1045 1046 static int dhcpv6_commit_advert(void) 1047 { 1048 return dhcpv6_promote_server_cand(); 1049 } 1050 1051 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc, 1052 const void *opt, const void *end, const struct sockaddr_in6 *from) 1053 { 1054 dhcpv6_handle_advert(orig, rc, opt, end, from); 1055 if (dhcpv6_commit_advert() < 0) 1056 return -1; 1057 1058 return dhcpv6_handle_reply(orig, rc, opt, end, from); 1059 } 1060 1061 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc, 1062 const void *opt, const void *end, const struct sockaddr_in6 *from) 1063 { 1064 uint8_t *odata; 1065 uint16_t otype, olen; 1066 uint32_t refresh = 86400; 1067 int ret = 1; 1068 unsigned int state_IAs; 1069 unsigned int updated_IAs = 0; 1070 bool handled_status_codes[_DHCPV6_Status_Max] = { false, }; 1071 1072 odhcp6c_expire(true); 1073 1074 if (orig == DHCPV6_MSG_UNKNOWN) { 1075 static time_t last_update = 0; 1076 time_t now = odhcp6c_get_milli_time() / 1000; 1077 1078 uint32_t elapsed = (last_update > 0) ? now - last_update : 0; 1079 last_update = now; 1080 1081 if (t1 != UINT32_MAX) 1082 t1 -= elapsed; 1083 1084 if (t2 != UINT32_MAX) 1085 t2 -= elapsed; 1086 1087 if (t3 != UINT32_MAX) 1088 t3 -= elapsed; 1089 1090 if (t1 < 0) 1091 t1 = 0; 1092 1093 if (t2 < 0) 1094 t2 = 0; 1095 1096 if (t3 < 0) 1097 t3 = 0; 1098 } 1099 1100 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) { 1101 // Delete NA and PD we have in the state from the Advert 1102 odhcp6c_clear_state(STATE_IA_NA); 1103 odhcp6c_clear_state(STATE_IA_PD); 1104 } 1105 1106 if (opt) { 1107 odhcp6c_clear_state(STATE_DNS); 1108 odhcp6c_clear_state(STATE_SEARCH); 1109 odhcp6c_clear_state(STATE_SNTP_IP); 1110 odhcp6c_clear_state(STATE_NTP_IP); 1111 odhcp6c_clear_state(STATE_NTP_FQDN); 1112 odhcp6c_clear_state(STATE_SIP_IP); 1113 odhcp6c_clear_state(STATE_SIP_FQDN); 1114 odhcp6c_clear_state(STATE_AFTR_NAME); 1115 odhcp6c_clear_state(STATE_CER); 1116 odhcp6c_clear_state(STATE_S46_MAPT); 1117 odhcp6c_clear_state(STATE_S46_MAPE); 1118 odhcp6c_clear_state(STATE_S46_LW); 1119 odhcp6c_clear_state(STATE_PASSTHRU); 1120 odhcp6c_clear_state(STATE_CUSTOM_OPTS); 1121 1122 // Parse and find all matching IAs 1123 dhcpv6_for_each_option(opt, end, otype, olen, odata) { 1124 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype); 1125 1126 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) 1127 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) { 1128 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]); 1129 1130 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) || 1131 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD)) 1132 continue; 1133 1134 // Test ID 1135 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA) 1136 continue; 1137 1138 uint16_t code = DHCPV6_Success; 1139 uint16_t stype, slen; 1140 uint8_t *sdata; 1141 // Get and handle status code 1142 dhcpv6_for_each_option(&ia_hdr[1], odata + olen, 1143 stype, slen, sdata) { 1144 if (stype == DHCPV6_OPT_STATUS && slen >= 2) { 1145 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL; 1146 uint16_t mlen = (slen > 2) ? slen - 2 : 0; 1147 1148 code = ((int)sdata[0]) << 8 | ((int)sdata[1]); 1149 1150 if (code == DHCPV6_Success) 1151 continue; 1152 1153 dhcpv6_handle_ia_status_code(orig, ia_hdr, 1154 code, mdata, mlen, handled_status_codes, &ret); 1155 1156 if (ret > 0) 1157 return ret; 1158 1159 break; 1160 } 1161 } 1162 1163 if (code != DHCPV6_Success) 1164 continue; 1165 1166 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen); 1167 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) { 1168 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST)) 1169 server_addr = *(struct in6_addr *)odata; 1170 1171 } 1172 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) { 1173 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL; 1174 uint16_t mlen = (olen > 2) ? olen - 2 : 0; 1175 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]); 1176 1177 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret); 1178 } else if (otype == DHCPV6_OPT_DNS_SERVERS) { 1179 if (olen % 16 == 0) 1180 odhcp6c_add_state(STATE_DNS, odata, olen); 1181 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) 1182 odhcp6c_add_state(STATE_SEARCH, odata, olen); 1183 else if (otype == DHCPV6_OPT_SNTP_SERVERS) { 1184 if (olen % 16 == 0) 1185 odhcp6c_add_state(STATE_SNTP_IP, odata, olen); 1186 } else if (otype == DHCPV6_OPT_NTP_SERVER) { 1187 uint16_t stype, slen; 1188 uint8_t *sdata; 1189 // Test status and bail if error 1190 dhcpv6_for_each_option(odata, odata + olen, 1191 stype, slen, sdata) { 1192 if (slen == 16 && (stype == NTP_MC_ADDR || 1193 stype == NTP_SRV_ADDR)) 1194 odhcp6c_add_state(STATE_NTP_IP, 1195 sdata, slen); 1196 else if (slen > 0 && stype == NTP_SRV_FQDN) 1197 odhcp6c_add_state(STATE_NTP_FQDN, 1198 sdata, slen); 1199 } 1200 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) { 1201 if (olen == 16) 1202 odhcp6c_add_state(STATE_SIP_IP, odata, olen); 1203 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) 1204 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen); 1205 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) { 1206 refresh = ntohl_unaligned(odata); 1207 } else if (otype == DHCPV6_OPT_AUTH) { 1208 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) { 1209 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4]; 1210 if (r->protocol == 3 && r->algorithm == 1 && 1211 r->reconf_type == 1) 1212 memcpy(reconf_key, r->key, sizeof(r->key)); 1213 } 1214 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) { 1215 size_t cur_len; 1216 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len); 1217 if (cur_len == 0) 1218 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen); 1219 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) { 1220 uint32_t sol_max_rt = ntohl_unaligned(odata); 1221 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN && 1222 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX) 1223 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt; 1224 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) { 1225 uint32_t inf_max_rt = ntohl_unaligned(odata); 1226 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN && 1227 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX) 1228 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt; 1229 #ifdef EXT_CER_ID 1230 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 + 1231 sizeof(struct dhcpv6_cer_id)) { 1232 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4]; 1233 struct in6_addr any = IN6ADDR_ANY_INIT; 1234 if (memcmp(&cer_id->addr, &any, sizeof(any))) 1235 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any)); 1236 #endif 1237 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) { 1238 odhcp6c_add_state(STATE_S46_MAPT, odata, olen); 1239 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) { 1240 size_t mape_len; 1241 odhcp6c_get_state(STATE_S46_MAPE, &mape_len); 1242 if (mape_len == 0) 1243 odhcp6c_add_state(STATE_S46_MAPE, odata, olen); 1244 } else if (otype == DHCPV6_OPT_S46_CONT_LW) { 1245 odhcp6c_add_state(STATE_S46_LW, odata, olen); 1246 } else 1247 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4); 1248 1249 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU)) 1250 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4); 1251 } 1252 } 1253 1254 // Bail out if fatal status code was received 1255 if (ret <= 0) 1256 return ret; 1257 1258 switch (orig) { 1259 case DHCPV6_MSG_REQUEST: 1260 case DHCPV6_MSG_REBIND: 1261 case DHCPV6_MSG_RENEW: 1262 state_IAs = dhcpv6_calc_refresh_timers(); 1263 // In case there're no state IA entries 1264 // keep sending request/renew/rebind messages 1265 if (state_IAs == 0) { 1266 ret = 0; 1267 break; 1268 } 1269 1270 if (orig == DHCPV6_MSG_REQUEST) { 1271 // All server candidates can be cleared if not yet bound 1272 if (!odhcp6c_is_bound()) 1273 dhcpv6_clear_all_server_cand(); 1274 1275 odhcp6c_clear_state(STATE_SERVER_ADDR); 1276 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16); 1277 } else if (orig == DHCPV6_MSG_RENEW) { 1278 // Send further renews if T1 is not set and if 1279 // there're IAs which were not in the Reply message 1280 if (!t1 && state_IAs != updated_IAs) { 1281 if (updated_IAs) 1282 // Publish updates 1283 script_call("updated", 0, false); 1284 1285 /* 1286 * RFC8415 states following in §18.2.10.1 : 1287 * Sends a Renew/Rebind if any of the IAs are not in the Reply 1288 * message, but as this likely indicates that the server that 1289 * responded does not support that IA type, sending immediately is 1290 * unlikely to produce a different result. Therefore, the client 1291 * MUST rate-limit its transmissions (see Section 14.1) and MAY just 1292 * wait for the normal retransmission time (as if the Reply message 1293 * had not been received). The client continues to use other 1294 * bindings for which the server did return information 1295 */ 1296 ret = -1; 1297 } 1298 } else if (orig == DHCPV6_MSG_REBIND) { 1299 odhcp6c_clear_state(STATE_SERVER_ADDR); 1300 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16); 1301 1302 // Send further rebinds if T1 and T2 is not set and if 1303 // there're IAs which were not in the Reply message 1304 if (!t1 && !t2 && state_IAs != updated_IAs) { 1305 if (updated_IAs) 1306 // Publish updates 1307 script_call("updated", 0, false); 1308 1309 /* 1310 * RFC8415 states following in §18.2.10.1 : 1311 * Sends a Renew/Rebind if any of the IAs are not in the Reply 1312 * message, but as this likely indicates that the server that 1313 * responded does not support that IA type, sending immediately is 1314 * unlikely to produce a different result. Therefore, the client 1315 * MUST rate-limit its transmissions (see Section 14.1) and MAY just 1316 * wait for the normal retransmission time (as if the Reply message 1317 * had not been received). The client continues to use other 1318 * bindings for which the server did return information 1319 */ 1320 ret = -1; 1321 } 1322 } 1323 break; 1324 1325 case DHCPV6_MSG_INFO_REQ: 1326 // All server candidates can be cleared if not yet bound 1327 if (!odhcp6c_is_bound()) 1328 dhcpv6_clear_all_server_cand(); 1329 1330 t1 = refresh; 1331 break; 1332 1333 default: 1334 break; 1335 } 1336 1337 return ret; 1338 } 1339 1340 static unsigned int dhcpv6_parse_ia(void *opt, void *end) 1341 { 1342 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt; 1343 unsigned int updated_IAs = 0; 1344 uint32_t t1, t2; 1345 uint16_t otype, olen; 1346 uint8_t *odata; 1347 char buf[INET6_ADDRSTRLEN]; 1348 1349 t1 = ntohl(ia_hdr->t1); 1350 t2 = ntohl(ia_hdr->t2); 1351 1352 if (t1 > t2 && t1 > 0 && t2 > 0) 1353 return 0; 1354 1355 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); 1356 1357 // Update address IA 1358 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) { 1359 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 1360 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0}; 1361 1362 entry.iaid = ia_hdr->iaid; 1363 1364 if (otype == DHCPV6_OPT_IA_PREFIX) { 1365 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4]; 1366 if (olen + 4U < sizeof(*prefix)) 1367 continue; 1368 1369 entry.valid = ntohl(prefix->valid); 1370 entry.preferred = ntohl(prefix->preferred); 1371 1372 if (entry.preferred > entry.valid) 1373 continue; 1374 1375 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX)); 1376 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX)); 1377 if (entry.t1 > entry.t2) 1378 entry.t1 = entry.t2; 1379 1380 entry.length = prefix->prefix; 1381 entry.target = prefix->addr; 1382 uint16_t stype, slen; 1383 uint8_t *sdata; 1384 1385 // Parse PD-exclude 1386 bool ok = true; 1387 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U, 1388 odata + olen, stype, slen, sdata) { 1389 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2) 1390 continue; 1391 1392 uint8_t elen = sdata[0]; 1393 if (elen > 64) 1394 elen = 64; 1395 1396 if (entry.length < 32 || elen <= entry.length) { 1397 ok = false; 1398 continue; 1399 } 1400 1401 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1; 1402 if (slen <= bytes) { 1403 ok = false; 1404 continue; 1405 } 1406 1407 uint32_t exclude = 0; 1408 do { 1409 exclude = exclude << 8 | sdata[bytes]; 1410 } while (--bytes); 1411 1412 exclude >>= 8 - ((elen - entry.length) % 8); 1413 exclude <<= 64 - elen; 1414 1415 // Abusing router & priority fields for exclusion 1416 entry.router = entry.target; 1417 entry.router.s6_addr32[1] |= htonl(exclude); 1418 entry.priority = elen; 1419 } 1420 1421 if (ok) { 1422 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0)) 1423 updated_IAs++; 1424 1425 syslog(LOG_INFO, "%s/%d preferred %d valid %d", 1426 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)), 1427 entry.length, entry.preferred , entry.valid); 1428 } 1429 1430 entry.priority = 0; 1431 memset(&entry.router, 0, sizeof(entry.router)); 1432 } else if (otype == DHCPV6_OPT_IA_ADDR) { 1433 struct dhcpv6_ia_addr *addr = (void*)&odata[-4]; 1434 if (olen + 4U < sizeof(*addr)) 1435 continue; 1436 1437 entry.preferred = ntohl(addr->preferred); 1438 entry.valid = ntohl(addr->valid); 1439 1440 if (entry.preferred > entry.valid) 1441 continue; 1442 1443 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX)); 1444 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX)); 1445 if (entry.t1 > entry.t2) 1446 entry.t1 = entry.t2; 1447 1448 entry.length = 128; 1449 entry.target = addr->addr; 1450 1451 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0)) 1452 updated_IAs++; 1453 1454 syslog(LOG_INFO, "%s preferred %d valid %d", 1455 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)), 1456 entry.preferred , entry.valid); 1457 } 1458 } 1459 1460 return updated_IAs; 1461 } 1462 1463 static unsigned int dhcpv6_calc_refresh_timers(void) 1464 { 1465 struct odhcp6c_entry *e; 1466 size_t ia_na_entries, ia_pd_entries, i; 1467 size_t invalid_entries = 0; 1468 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0; 1469 1470 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries); 1471 ia_na_entries /= sizeof(*e); 1472 1473 for (i = 0; i < ia_na_entries; i++) { 1474 /* Exclude invalid IA_NA entries */ 1475 if (!e[i].valid) { 1476 invalid_entries++; 1477 continue; 1478 } 1479 1480 if (e[i].t1 < l_t1) 1481 l_t1 = e[i].t1; 1482 1483 if (e[i].t2 < l_t2) 1484 l_t2 = e[i].t2; 1485 1486 if (e[i].valid > l_t3) 1487 l_t3 = e[i].valid; 1488 } 1489 1490 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries); 1491 ia_pd_entries /= sizeof(*e); 1492 1493 for (i = 0; i < ia_pd_entries; i++) { 1494 /* Exclude invalid IA_PD entries */ 1495 if (!e[i].valid) { 1496 invalid_entries++; 1497 continue; 1498 } 1499 1500 if (e[i].t1 < l_t1) 1501 l_t1 = e[i].t1; 1502 1503 if (e[i].t2 < l_t2) 1504 l_t2 = e[i].t2; 1505 1506 if (e[i].valid > l_t3) 1507 l_t3 = e[i].valid; 1508 } 1509 1510 if (ia_pd_entries + ia_na_entries - invalid_entries) { 1511 t1 = l_t1; 1512 t2 = l_t2; 1513 t3 = l_t3; 1514 1515 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3); 1516 } 1517 1518 return (unsigned int)(ia_pd_entries + ia_na_entries); 1519 } 1520 1521 static void dhcpv6_log_status_code(const uint16_t code, const char *scope, 1522 const void *status_msg, int len) 1523 { 1524 const char *src = status_msg; 1525 char buf[len + 3]; 1526 char *dst = buf; 1527 1528 if (len) { 1529 *dst++ = '('; 1530 while (len--) { 1531 *dst = isprint((unsigned char)*src) ? *src : '?'; 1532 src++; 1533 dst++; 1534 } 1535 *dst++ = ')'; 1536 } 1537 1538 *dst = 0; 1539 1540 syslog(LOG_WARNING, "Server returned %s status '%s %s'", 1541 scope, dhcpv6_status_code_to_str(code), buf); 1542 } 1543 1544 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig, 1545 const uint16_t code, const void *status_msg, const int len, 1546 int *ret) 1547 { 1548 dhcpv6_log_status_code(code, "message", status_msg, len); 1549 1550 switch (code) { 1551 case DHCPV6_UnspecFail: 1552 // Generic failure 1553 *ret = 0; 1554 break; 1555 1556 case DHCPV6_UseMulticast: 1557 switch(orig) { 1558 case DHCPV6_MSG_REQUEST: 1559 case DHCPV6_MSG_RENEW: 1560 case DHCPV6_MSG_RELEASE: 1561 case DHCPV6_MSG_DECLINE: 1562 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8 1563 server_addr = in6addr_any; 1564 *ret = 0; 1565 break; 1566 default: 1567 break; 1568 } 1569 break; 1570 1571 case DHCPV6_NoAddrsAvail: 1572 case DHCPV6_NoPrefixAvail: 1573 if (orig == DHCPV6_MSG_REQUEST) 1574 *ret = 0; // Failure 1575 break; 1576 1577 default: 1578 break; 1579 } 1580 } 1581 1582 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig, 1583 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code, 1584 const void *status_msg, const int len, 1585 bool handled_status_codes[_DHCPV6_Status_Max], int *ret) 1586 { 1587 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ? 1588 "IA_NA" : "IA_PD", status_msg, len); 1589 1590 switch (code) { 1591 case DHCPV6_NoBinding: 1592 switch (orig) { 1593 case DHCPV6_MSG_RENEW: 1594 case DHCPV6_MSG_REBIND: 1595 if ((*ret > 0) && !handled_status_codes[code]) 1596 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST); 1597 break; 1598 1599 default: 1600 break; 1601 } 1602 break; 1603 1604 default: 1605 *ret = 0; 1606 break; 1607 } 1608 } 1609 1610 // Note this always takes ownership of cand->ia_na and cand->ia_pd 1611 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand) 1612 { 1613 size_t cand_len, i; 1614 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1615 1616 // Remove identical duid server candidate 1617 for (i = 0; i < cand_len / sizeof(*c); ++i) { 1618 if (cand->duid_len == c[i].duid_len && 1619 !memcmp(cand->duid, c[i].duid, cand->duid_len)) { 1620 free(c[i].ia_na); 1621 free(c[i].ia_pd); 1622 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c)); 1623 break; 1624 } 1625 } 1626 1627 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1628 i < cand_len / sizeof(*c); ++i) { 1629 if (c[i].preference < cand->preference) 1630 break; 1631 } 1632 1633 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) { 1634 free(cand->ia_na); 1635 free(cand->ia_pd); 1636 } 1637 } 1638 1639 static void dhcpv6_clear_all_server_cand(void) 1640 { 1641 size_t cand_len, i; 1642 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1643 1644 // Server candidates need deep delete for IA_NA/IA_PD 1645 for (i = 0; i < cand_len / sizeof(*c); ++i) { 1646 free(c[i].ia_na); 1647 free(c[i].ia_pd); 1648 } 1649 odhcp6c_clear_state(STATE_SERVER_CAND); 1650 } 1651 1652 int dhcpv6_promote_server_cand(void) 1653 { 1654 size_t cand_len; 1655 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len); 1656 uint16_t hdr[2]; 1657 int ret = DHCPV6_STATELESS; 1658 1659 // Clear lingering candidate state info 1660 odhcp6c_clear_state(STATE_SERVER_ID); 1661 odhcp6c_clear_state(STATE_IA_NA); 1662 odhcp6c_clear_state(STATE_IA_PD); 1663 1664 if (!cand_len) 1665 return -1; 1666 1667 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) { 1668 na_mode = IA_MODE_NONE; 1669 1670 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt; 1671 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt; 1672 1673 return dhcpv6_request(DHCPV6_MSG_SOLICIT); 1674 } 1675 1676 hdr[0] = htons(DHCPV6_OPT_SERVERID); 1677 hdr[1] = htons(cand->duid_len); 1678 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr)); 1679 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len); 1680 accept_reconfig = cand->wants_reconfigure; 1681 1682 if (cand->ia_na_len) { 1683 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len); 1684 free(cand->ia_na); 1685 if (na_mode != IA_MODE_NONE) 1686 ret = DHCPV6_STATEFUL; 1687 } 1688 1689 if (cand->ia_pd_len) { 1690 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len); 1691 free(cand->ia_pd); 1692 if (pd_mode != IA_MODE_NONE) 1693 ret = DHCPV6_STATEFUL; 1694 } 1695 1696 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt; 1697 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt; 1698 1699 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand)); 1700 1701 return ret; 1702 } 1703
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