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[project/odhcp6c.git] / src / dhcpv6.c
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 accept_reconfig = false;
108 // Server unicast address
109 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
110
111 // Reconfigure key
112 static uint8_t reconf_key[16];
113
114 // client options
115 static unsigned int client_options = 0;
116
117 static uint32_t ntohl_unaligned(const uint8_t *data)
118 {
119 uint32_t buf;
120
121 memcpy(&buf, data, sizeof(buf));
122 return ntohl(buf);
123 }
124
125 static char *dhcpv6_msg_to_str(enum dhcpv6_msg msg)
126 {
127 switch (msg) {
128 case DHCPV6_MSG_SOLICIT:
129 return "SOLICIT";
130
131 case DHCPV6_MSG_ADVERT:
132 return "ADVERTISE";
133
134 case DHCPV6_MSG_REQUEST:
135 return "REQUEST";
136
137 case DHCPV6_MSG_RENEW:
138 return "RENEW";
139
140 case DHCPV6_MSG_REBIND:
141 return "REBIND";
142
143 case DHCPV6_MSG_REPLY:
144 return "REPLY";
145
146 case DHCPV6_MSG_RELEASE:
147 return "RELEASE";
148
149 case DHCPV6_MSG_DECLINE:
150 return "DECLINE";
151
152 case DHCPV6_MSG_RECONF:
153 return "RECONFIGURE";
154
155 case DHCPV6_MSG_INFO_REQ:
156 return "INFORMATION REQUEST";
157
158 default:
159 break;
160 }
161
162 return "UNKNOWN";
163 }
164
165 static char *dhcpv6_status_code_to_str(uint16_t code)
166 {
167 switch (code) {
168 case DHCPV6_Success:
169 return "Success";
170
171 case DHCPV6_UnspecFail:
172 return "Unspecified Failure";
173
174 case DHCPV6_NoAddrsAvail:
175 return "No Address Available";
176
177 case DHCPV6_NoBinding:
178 return "No Binding";
179
180 case DHCPV6_NotOnLink:
181 return "Not On Link";
182
183 case DHCPV6_UseMulticast:
184 return "Use Multicast";
185
186 case DHCPV6_NoPrefixAvail:
187 return "No Prefix Available";
188
189 default:
190 break;
191 }
192
193 return "Unknown";
194 }
195
196 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
197 {
198 client_options = options;
199 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
200
201 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
202 if (sock < 0)
203 goto failure;
204
205 // Detect interface
206 struct ifreq ifr;
207 memset(&ifr, 0, sizeof(ifr));
208 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
209 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
210 goto failure;
211
212 ifindex = ifr.ifr_ifindex;
213
214 // Create client DUID
215 size_t client_id_len;
216 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
217 if (client_id_len == 0) {
218 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
219 DHCPV6_DUID_LLADDR, 0, 1};
220
221 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
222 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
223
224 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
225 struct ifreq ifs[100], *ifp, *ifend;
226 struct ifconf ifc;
227 ifc.ifc_req = ifs;
228 ifc.ifc_len = sizeof(ifs);
229
230 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
231 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
232 // If our interface doesn't have an address...
233 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
234 for (ifp = ifc.ifc_req; ifp < ifend &&
235 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
236 memcpy(ifr.ifr_name, ifp->ifr_name,
237 sizeof(ifr.ifr_name));
238 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
239 continue;
240
241 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
242 ETHER_ADDR_LEN);
243 }
244 }
245
246 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
247 }
248
249 // Create ORO
250 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
251 uint16_t oro[] = {
252 htons(DHCPV6_OPT_SIP_SERVER_D),
253 htons(DHCPV6_OPT_SIP_SERVER_A),
254 htons(DHCPV6_OPT_DNS_SERVERS),
255 htons(DHCPV6_OPT_DNS_DOMAIN),
256 htons(DHCPV6_OPT_SNTP_SERVERS),
257 htons(DHCPV6_OPT_NTP_SERVER),
258 htons(DHCPV6_OPT_AFTR_NAME),
259 htons(DHCPV6_OPT_PD_EXCLUDE),
260 #ifdef EXT_CER_ID
261 htons(DHCPV6_OPT_CER_ID),
262 #endif
263 htons(DHCPV6_OPT_S46_CONT_MAPE),
264 htons(DHCPV6_OPT_S46_CONT_MAPT),
265 htons(DHCPV6_OPT_S46_CONT_LW),
266 };
267 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
268 }
269 // Required oro
270 uint16_t req_oro[] = {
271 htons(DHCPV6_OPT_INF_MAX_RT),
272 htons(DHCPV6_OPT_SOL_MAX_RT),
273 htons(DHCPV6_OPT_INFO_REFRESH),
274 };
275 odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro));
276
277 // Configure IPv6-options
278 int val = 1;
279 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
280 goto failure;
281
282 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
283 goto failure;
284
285 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
286 goto failure;
287
288 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 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)
321 {
322 int mode = DHCPV6_UNKNOWN;
323
324 na_mode = na;
325 pd_mode = pd;
326
327 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
328 mode = DHCPV6_STATELESS;
329 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
330 mode = DHCPV6_STATEFUL;
331
332 return mode;
333 }
334
335 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
336 {
337 // Build FQDN
338 char fqdn_buf[256];
339 gethostname(fqdn_buf, sizeof(fqdn_buf));
340 struct {
341 uint16_t type;
342 uint16_t len;
343 uint8_t flags;
344 uint8_t data[256];
345 } fqdn;
346 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
347 sizeof(fqdn.data), NULL, NULL);
348 fqdn.type = htons(DHCPV6_OPT_FQDN);
349 fqdn.len = htons(fqdn_len - 4);
350 fqdn.flags = 0;
351
352 // Build Client ID
353 size_t cl_id_len;
354 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
355
356 // Get Server ID
357 size_t srv_id_len;
358 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
359
360 // Build IA_PDs
361 size_t ia_pd_entries = 0, ia_pd_len = 0;
362 uint8_t *ia_pd;
363
364 if (type == DHCPV6_MSG_SOLICIT) {
365 odhcp6c_clear_state(STATE_IA_PD);
366 size_t n_prefixes;
367 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
368 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
369
370 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
371
372 for (size_t i = 0; i < n_prefixes; i++) {
373 struct dhcpv6_ia_hdr hdr_ia_pd = {
374 htons(DHCPV6_OPT_IA_PD),
375 htons(sizeof(hdr_ia_pd) - 4 +
376 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
377 request_prefixes[i].iaid, 0, 0
378 };
379 struct dhcpv6_ia_prefix pref = {
380 .type = htons(DHCPV6_OPT_IA_PREFIX),
381 .len = htons(sizeof(pref) - 4),
382 .prefix = request_prefixes[i].length
383 };
384 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
385 ia_pd_len += sizeof(hdr_ia_pd);
386 if (request_prefixes[i].length) {
387 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
388 ia_pd_len += sizeof(pref);
389 }
390 }
391 } else {
392 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
393 ia_pd_entries /= sizeof(*e);
394
395 // we're too lazy to count our distinct IAIDs,
396 // so just allocate maximally needed space
397 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
398 sizeof(struct dhcpv6_ia_hdr)));
399
400 for (size_t i = 0; i < ia_pd_entries; ++i) {
401 uint32_t iaid = e[i].iaid;
402
403 // check if this is an unprocessed IAID and skip if not.
404 int new_iaid = 1;
405 for (int j = i-1; j >= 0; j--) {
406 if (e[j].iaid == iaid) {
407 new_iaid = 0;
408 break;
409 }
410 }
411
412 if (!new_iaid)
413 continue;
414
415 // construct header
416 struct dhcpv6_ia_hdr hdr_ia_pd = {
417 htons(DHCPV6_OPT_IA_PD),
418 htons(sizeof(hdr_ia_pd) - 4),
419 iaid, 0, 0
420 };
421
422 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
423 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
424 ia_pd_len += sizeof(hdr_ia_pd);
425
426 for (size_t j = i; j < ia_pd_entries; j++) {
427 if (e[j].iaid != iaid)
428 continue;
429
430 uint8_t ex_len = 0;
431 if (e[j].priority > 0)
432 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
433
434 struct dhcpv6_ia_prefix p = {
435 .type = htons(DHCPV6_OPT_IA_PREFIX),
436 .len = htons(sizeof(p) - 4U + ex_len),
437 .prefix = e[j].length,
438 .addr = e[j].target
439 };
440
441 if (type == DHCPV6_MSG_REQUEST) {
442 p.preferred = htonl(e[j].preferred);
443 p.valid = htonl(e[j].valid);
444 }
445
446 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
447 ia_pd_len += sizeof(p);
448
449 if (ex_len) {
450 ia_pd[ia_pd_len++] = 0;
451 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
452 ia_pd[ia_pd_len++] = 0;
453 ia_pd[ia_pd_len++] = ex_len - 4;
454 ia_pd[ia_pd_len++] = e[j].priority;
455
456 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
457 excl >>= (64 - e[j].priority);
458 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
459
460 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
461 ia_pd[ia_pd_len + i] = excl & 0xff;
462 ia_pd_len += ex_len - 5;
463 }
464
465 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
466 }
467 }
468 }
469
470 // Build IA_NAs
471 size_t ia_na_entries, ia_na_len = 0;
472 void *ia_na = NULL;
473 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
474 ia_na_entries /= sizeof(*e);
475
476 struct dhcpv6_ia_hdr hdr_ia_na = {
477 htons(DHCPV6_OPT_IA_NA),
478 htons(sizeof(hdr_ia_na) - 4),
479 htonl(1), 0, 0
480 };
481
482 struct dhcpv6_ia_addr pa[ia_na_entries];
483 for (size_t i = 0; i < ia_na_entries; ++i) {
484 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
485 pa[i].len = htons(sizeof(pa[i]) - 4U);
486 pa[i].addr = e[i].target;
487
488 if (type == DHCPV6_MSG_REQUEST) {
489 pa[i].preferred = htonl(e[i].preferred);
490 pa[i].valid = htonl(e[i].valid);
491 } else {
492 pa[i].preferred = 0;
493 pa[i].valid = 0;
494 }
495 }
496
497 ia_na = pa;
498 ia_na_len = sizeof(pa);
499 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
500
501 // Reconfigure Accept
502 struct {
503 uint16_t type;
504 uint16_t length;
505 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
506
507 // Option list
508 size_t opts_len;
509 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
510
511 // Option Request List
512 size_t oro_entries, oro_len = 0;
513 uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries);
514
515 oro_entries /= sizeof(*s_oro);
516 oro = alloca(oro_entries * sizeof(*oro));
517
518 for (size_t i = 0; i < oro_entries; i++) {
519 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i]));
520
521 if (opt) {
522 if (!(opt->flags & OPT_ORO))
523 continue;
524
525 if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT)
526 continue;
527
528 if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ)
529 continue;
530
531 if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ)
532 continue;
533 }
534
535 oro[oro_len++] = s_oro[i];
536 }
537 oro_len *= sizeof(*oro);
538
539 // Prepare Header
540 struct {
541 uint8_t type;
542 uint8_t trid[3];
543 uint16_t elapsed_type;
544 uint16_t elapsed_len;
545 uint16_t elapsed_value;
546 uint16_t oro_type;
547 uint16_t oro_len;
548 } hdr = {
549 type, {trid[0], trid[1], trid[2]},
550 htons(DHCPV6_OPT_ELAPSED), htons(2),
551 htons((ecs > 0xffff) ? 0xffff : ecs),
552 htons(DHCPV6_OPT_ORO), htons(oro_len),
553 };
554
555 struct iovec iov[IOV_TOTAL] = {
556 [IOV_HDR] = {&hdr, sizeof(hdr)},
557 [IOV_ORO] = {oro, oro_len},
558 [IOV_CL_ID] = {cl_id, cl_id_len},
559 [IOV_SRV_ID] = {srv_id, srv_id_len},
560 [IOV_OPTS] = { opts, opts_len },
561 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
562 [IOV_FQDN] = {&fqdn, fqdn_len},
563 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
564 [IOV_IA_NA] = {ia_na, ia_na_len},
565 [IOV_IA_PD] = {ia_pd, ia_pd_len},
566 };
567
568 size_t cnt = IOV_TOTAL;
569 if (type == DHCPV6_MSG_INFO_REQ)
570 cnt = IOV_HDR_IA_NA;
571
572 // Disable IAs if not used
573 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
574 iov[IOV_HDR_IA_NA].iov_len = 0;
575
576 if (na_mode == IA_MODE_NONE)
577 iov[IOV_HDR_IA_NA].iov_len = 0;
578
579 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
580 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
581 iov[IOV_RECONF_ACCEPT].iov_len = 0;
582
583 if (!(client_options & DHCPV6_CLIENT_FQDN))
584 iov[IOV_FQDN].iov_len = 0;
585
586 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
587 0, ALL_DHCPV6_RELAYS, ifindex};
588 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
589 .msg_iov = iov, .msg_iovlen = cnt};
590
591 switch (type) {
592 case DHCPV6_MSG_REQUEST:
593 case DHCPV6_MSG_RENEW:
594 case DHCPV6_MSG_RELEASE:
595 case DHCPV6_MSG_DECLINE:
596 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
597 odhcp6c_addr_in_scope(&server_addr)) {
598 srv.sin6_addr = server_addr;
599 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
600 srv.sin6_scope_id = 0;
601 }
602 break;
603 default:
604 break;
605 }
606
607 if (sendmsg(sock, &msg, 0) < 0) {
608 char in6_str[INET6_ADDRSTRLEN];
609
610 syslog(LOG_ERR, "Failed to send %s message to %s (%s)",
611 dhcpv6_msg_to_str(type),
612 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
613 in6_str, sizeof(in6_str)), strerror(errno));
614 }
615 }
616
617 static int64_t dhcpv6_rand_delay(int64_t time)
618 {
619 int random;
620 odhcp6c_random(&random, sizeof(random));
621
622 return (time * ((int64_t)random % 1000LL)) / 10000LL;
623 }
624
625 int dhcpv6_request(enum dhcpv6_msg type)
626 {
627 uint8_t rc = 0;
628 uint64_t timeout = UINT32_MAX;
629 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
630
631 if (retx->delay) {
632 struct timespec ts = {0, 0};
633 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
634
635 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
636 }
637
638 if (type == DHCPV6_MSG_UNKNOWN)
639 timeout = t1;
640 else if (type == DHCPV6_MSG_RENEW)
641 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
642 else if (type == DHCPV6_MSG_REBIND)
643 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
644
645 if (timeout == 0)
646 return -1;
647
648 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
649 retx->name, timeout, retx->max_rc);
650
651 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
652
653 // Generate transaction ID
654 uint8_t trid[3] = {0, 0, 0};
655 if (type != DHCPV6_MSG_UNKNOWN)
656 odhcp6c_random(trid, sizeof(trid));
657
658 ssize_t len = -1;
659 int64_t rto = 0;
660
661 do {
662 if (rto == 0) {
663 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
664
665 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
666 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
667 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
668
669 rto = (retx->init_timeo * 1000 + delay);
670 } else
671 rto = (2 * rto + dhcpv6_rand_delay(rto));
672
673 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
674 rto = retx->max_timeo * 1000 +
675 dhcpv6_rand_delay(retx->max_timeo * 1000);
676
677 // Calculate end for this round and elapsed time
678 uint64_t round_end = round_start + rto;
679 elapsed = round_start - start;
680
681 // Don't wait too long if timeout differs from infinite
682 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
683 round_end = timeout * 1000 + start;
684
685 // Built and send package
686 switch (type) {
687 case DHCPV6_MSG_UNKNOWN:
688 break;
689 default:
690 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
691 retx->name, elapsed, rc);
692 // Fall through
693 case DHCPV6_MSG_SOLICIT:
694 case DHCPV6_MSG_INFO_REQ:
695 dhcpv6_send(type, trid, elapsed / 10);
696 rc++;
697 }
698
699 // Receive rounds
700 for (; len < 0 && (round_start < round_end);
701 round_start = odhcp6c_get_milli_time()) {
702 uint8_t buf[1536];
703 union {
704 struct cmsghdr hdr;
705 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
706 } cmsg_buf;
707 struct iovec iov = {buf, sizeof(buf)};
708 struct sockaddr_in6 addr;
709 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
710 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
711 .msg_controllen = sizeof(cmsg_buf)};
712 struct in6_pktinfo *pktinfo = NULL;
713 const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf;
714
715 // Check for pending signal
716 if (odhcp6c_signal_process())
717 return -1;
718
719 // Set timeout for receiving
720 uint64_t t = round_end - round_start;
721 struct timeval tv = {t / 1000, (t % 1000) * 1000};
722 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
723 &tv, sizeof(tv)) < 0)
724 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
725 strerror(errno));
726
727 // Receive cycle
728 len = recvmsg(sock, &msg, 0);
729 if (len < 0)
730 continue;
731
732 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
733 ch = CMSG_NXTHDR(&msg, ch)) {
734 if (ch->cmsg_level == SOL_IPV6 &&
735 ch->cmsg_type == IPV6_PKTINFO) {
736 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
737 break;
738 }
739 }
740
741 if (pktinfo == NULL) {
742 len = -1;
743 continue;
744 }
745
746 if (!dhcpv6_response_is_valid(buf, len, trid,
747 type, &pktinfo->ipi6_addr)) {
748 len = -1;
749 continue;
750 }
751
752 uint8_t *opt = &buf[4];
753 uint8_t *opt_end = opt + len - 4;
754
755 round_start = odhcp6c_get_milli_time();
756 elapsed = round_start - start;
757 syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms",
758 dhcpv6_msg_to_str(hdr->msg_type), elapsed);
759
760 if (retx->handler_reply)
761 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
762
763 if (len > 0 && round_end - round_start > 1000)
764 round_end = 1000 + round_start;
765 }
766
767 // Allow
768 if (retx->handler_finish)
769 len = retx->handler_finish();
770 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
771 (!retx->max_rc || rc < retx->max_rc));
772 return len;
773 }
774
775 // Message validation checks according to RFC3315 chapter 15
776 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
777 const uint8_t transaction[3], enum dhcpv6_msg type,
778 const struct in6_addr *daddr)
779 {
780 const struct dhcpv6_header *rep = buf;
781 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
782 transaction, sizeof(rep->tr_id)))
783 return false; // Invalid reply
784
785 if (type == DHCPV6_MSG_SOLICIT) {
786 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
787 rep->msg_type != DHCPV6_MSG_REPLY)
788 return false;
789
790 } else if (type == DHCPV6_MSG_UNKNOWN) {
791 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
792 return false;
793
794 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
795 return false;
796
797 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
798 rcmsg = DHCPV6_MSG_UNKNOWN;
799 uint16_t otype, olen = UINT16_MAX;
800 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
801 ia_present = false, options_valid = true;
802
803 size_t client_id_len, server_id_len;
804 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
805 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
806
807 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
808 if (otype == DHCPV6_OPT_CLIENTID) {
809 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
810 &odata[-4], client_id, client_id_len);
811 } else if (otype == DHCPV6_OPT_SERVERID) {
812 if (server_id_len)
813 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
814 &odata[-4], server_id, server_id_len);
815 else
816 serverid_ok = true;
817 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
818 sizeof(struct dhcpv6_auth_reconfigure)) {
819 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
820 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
821 continue;
822
823 md5_ctx_t md5;
824 uint8_t serverhash[16], secretbytes[64];
825 uint32_t hash[4];
826 memcpy(serverhash, r->key, sizeof(serverhash));
827 memset(r->key, 0, sizeof(r->key));
828
829 memset(secretbytes, 0, sizeof(secretbytes));
830 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
831
832 for (size_t i = 0; i < sizeof(secretbytes); ++i)
833 secretbytes[i] ^= 0x36;
834
835 md5_begin(&md5);
836 md5_hash(secretbytes, sizeof(secretbytes), &md5);
837 md5_hash(buf, len, &md5);
838 md5_end(hash, &md5);
839
840 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
841 secretbytes[i] ^= 0x36;
842 secretbytes[i] ^= 0x5c;
843 }
844
845 md5_begin(&md5);
846 md5_hash(secretbytes, sizeof(secretbytes), &md5);
847 md5_hash(hash, 16, &md5);
848 md5_end(hash, &md5);
849
850 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
851 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
852 rcmsg = odata[0];
853 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
854 ia_present = true;
855 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
856 options_valid = false;
857 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
858 (otype == DHCPV6_OPT_PD_EXCLUDE))
859 // Options are not allowed on global level
860 options_valid = false;
861 }
862
863 if (!options_valid || ((odata + olen) > end))
864 return false;
865
866 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
867 return false;
868
869 if (rep->msg_type == DHCPV6_MSG_RECONF) {
870 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
871 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
872 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
873 return false;
874 }
875
876 return clientid_ok && serverid_ok;
877 }
878
879 int dhcpv6_poll_reconfigure(void)
880 {
881 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
882
883 switch (ret) {
884 /*
885 * Only RENEW/REBIND/INFORMATION REQUEST
886 * message transmission can be requested
887 * by a RECONFIGURE
888 */
889 case DHCPV6_MSG_RENEW:
890 case DHCPV6_MSG_REBIND:
891 case DHCPV6_MSG_INFO_REQ:
892 ret = dhcpv6_request(ret);
893 break;
894
895 default:
896 break;
897 }
898
899 return ret;
900 }
901
902 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
903 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
904 {
905 uint16_t otype, olen;
906 uint8_t *odata;
907 enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN;
908
909 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
910 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
911 switch (odata[0]) {
912 case DHCPV6_MSG_REBIND:
913 if (t2 != UINT32_MAX)
914 t2 = 0;
915 // Fall through
916 case DHCPV6_MSG_RENEW:
917 if (t1 != UINT32_MAX)
918 t1 = 0;
919 // Fall through
920 case DHCPV6_MSG_INFO_REQ:
921 msg = odata[0];
922 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s",
923 dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF));
924 break;
925
926 default:
927 break;
928 }
929 }
930 }
931
932 if (msg != DHCPV6_MSG_UNKNOWN)
933 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
934
935 return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg);
936 }
937
938 // Collect all advertised servers
939 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
940 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
941 {
942 uint16_t olen, otype;
943 uint8_t *odata, pref = 0;
944 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
945 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
946 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
947 bool have_na = false;
948 int have_pd = 0;
949
950 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
951 if (orig == DHCPV6_MSG_SOLICIT &&
952 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
953 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
954 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
955 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
956 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
957 }
958
959 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
960 memcpy(cand.duid, odata, olen);
961 cand.duid_len = olen;
962 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
963 cand.preference >= 0) {
964 cand.preference = pref = odata[0];
965 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
966 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
967 cand.server_addr = *(struct in6_addr *)odata;
968
969 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
970 cand.wants_reconfigure = true;
971 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
972 uint32_t sol_max_rt = ntohl_unaligned(odata);
973 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
974 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
975 cand.sol_max_rt = sol_max_rt;
976
977 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
978 uint32_t inf_max_rt = ntohl_unaligned(odata);
979 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
980 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
981 cand.inf_max_rt = inf_max_rt;
982
983 } else if (otype == DHCPV6_OPT_IA_PD &&
984 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
985 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
986 uint8_t *oend = odata + olen, *d;
987 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
988 if (otype == DHCPV6_OPT_IA_PREFIX &&
989 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
990 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
991 have_pd = p->prefix;
992 }
993 }
994 } else if (otype == DHCPV6_OPT_IA_NA &&
995 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
996 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
997 uint8_t *oend = odata + olen, *d;
998
999 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
1000 if (otype == DHCPV6_OPT_IA_ADDR &&
1001 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
1002 have_na = true;
1003 }
1004 }
1005 }
1006
1007 if ((!have_na && na_mode == IA_MODE_FORCE) ||
1008 (!have_pd && pd_mode == IA_MODE_FORCE)) {
1009 /*
1010 * RFC7083 states to process the SOL_MAX_RT and
1011 * INF_MAX_RT options even if the DHCPv6 server
1012 * did not propose any IA_NA and/or IA_PD
1013 */
1014 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
1015 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
1016 return -1;
1017 }
1018
1019 if (na_mode != IA_MODE_NONE && !have_na) {
1020 cand.has_noaddravail = true;
1021 cand.preference -= 1000;
1022 }
1023
1024 if (pd_mode != IA_MODE_NONE) {
1025 if (have_pd)
1026 cand.preference += 2000 + (128 - have_pd);
1027 else
1028 cand.preference -= 2000;
1029 }
1030
1031 if (cand.duid_len > 0) {
1032 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
1033 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
1034 dhcpv6_add_server_cand(&cand);
1035 }
1036
1037 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
1038 }
1039
1040 static int dhcpv6_commit_advert(void)
1041 {
1042 return dhcpv6_promote_server_cand();
1043 }
1044
1045 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
1046 const void *opt, const void *end, const struct sockaddr_in6 *from)
1047 {
1048 dhcpv6_handle_advert(orig, rc, opt, end, from);
1049 if (dhcpv6_commit_advert() < 0)
1050 return -1;
1051
1052 return dhcpv6_handle_reply(orig, rc, opt, end, from);
1053 }
1054
1055 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
1056 const void *opt, const void *end, const struct sockaddr_in6 *from)
1057 {
1058 uint8_t *odata;
1059 uint16_t otype, olen;
1060 uint32_t refresh = 86400;
1061 int ret = 1;
1062 unsigned int state_IAs;
1063 unsigned int updated_IAs = 0;
1064 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
1065
1066 odhcp6c_expire(true);
1067
1068 if (orig == DHCPV6_MSG_UNKNOWN) {
1069 static time_t last_update = 0;
1070 time_t now = odhcp6c_get_milli_time() / 1000;
1071
1072 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
1073 last_update = now;
1074
1075 if (t1 != UINT32_MAX)
1076 t1 -= elapsed;
1077
1078 if (t2 != UINT32_MAX)
1079 t2 -= elapsed;
1080
1081 if (t3 != UINT32_MAX)
1082 t3 -= elapsed;
1083
1084 if (t1 < 0)
1085 t1 = 0;
1086
1087 if (t2 < 0)
1088 t2 = 0;
1089
1090 if (t3 < 0)
1091 t3 = 0;
1092 }
1093
1094 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1095 // Delete NA and PD we have in the state from the Advert
1096 odhcp6c_clear_state(STATE_IA_NA);
1097 odhcp6c_clear_state(STATE_IA_PD);
1098 }
1099
1100 if (opt) {
1101 odhcp6c_clear_state(STATE_DNS);
1102 odhcp6c_clear_state(STATE_SEARCH);
1103 odhcp6c_clear_state(STATE_SNTP_IP);
1104 odhcp6c_clear_state(STATE_NTP_IP);
1105 odhcp6c_clear_state(STATE_NTP_FQDN);
1106 odhcp6c_clear_state(STATE_SIP_IP);
1107 odhcp6c_clear_state(STATE_SIP_FQDN);
1108 odhcp6c_clear_state(STATE_AFTR_NAME);
1109 odhcp6c_clear_state(STATE_CER);
1110 odhcp6c_clear_state(STATE_S46_MAPT);
1111 odhcp6c_clear_state(STATE_S46_MAPE);
1112 odhcp6c_clear_state(STATE_S46_LW);
1113 odhcp6c_clear_state(STATE_PASSTHRU);
1114 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1115
1116 // Parse and find all matching IAs
1117 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1118 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1119
1120 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1121 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1122 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1123
1124 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1125 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1126 continue;
1127
1128 // Test ID
1129 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1130 continue;
1131
1132 uint16_t code = DHCPV6_Success;
1133 uint16_t stype, slen;
1134 uint8_t *sdata;
1135 // Get and handle status code
1136 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1137 stype, slen, sdata) {
1138 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1139 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1140 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1141
1142 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1143
1144 if (code == DHCPV6_Success)
1145 continue;
1146
1147 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1148 code, mdata, mlen, handled_status_codes, &ret);
1149
1150 if (ret > 0)
1151 return ret;
1152
1153 break;
1154 }
1155 }
1156
1157 if (code != DHCPV6_Success)
1158 continue;
1159
1160 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1161 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1162 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1163 server_addr = *(struct in6_addr *)odata;
1164
1165 }
1166 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1167 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1168 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1169 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1170
1171 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1172 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1173 if (olen % 16 == 0)
1174 odhcp6c_add_state(STATE_DNS, odata, olen);
1175 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1176 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1177 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1178 if (olen % 16 == 0)
1179 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1180 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1181 uint16_t stype, slen;
1182 uint8_t *sdata;
1183 // Test status and bail if error
1184 dhcpv6_for_each_option(odata, odata + olen,
1185 stype, slen, sdata) {
1186 if (slen == 16 && (stype == NTP_MC_ADDR ||
1187 stype == NTP_SRV_ADDR))
1188 odhcp6c_add_state(STATE_NTP_IP,
1189 sdata, slen);
1190 else if (slen > 0 && stype == NTP_SRV_FQDN)
1191 odhcp6c_add_state(STATE_NTP_FQDN,
1192 sdata, slen);
1193 }
1194 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1195 if (olen == 16)
1196 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1197 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1198 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1199 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1200 refresh = ntohl_unaligned(odata);
1201 } else if (otype == DHCPV6_OPT_AUTH) {
1202 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1203 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1204 if (r->protocol == 3 && r->algorithm == 1 &&
1205 r->reconf_type == 1)
1206 memcpy(reconf_key, r->key, sizeof(r->key));
1207 }
1208 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1209 size_t cur_len;
1210 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1211 if (cur_len == 0)
1212 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1213 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1214 uint32_t sol_max_rt = ntohl_unaligned(odata);
1215 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1216 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1217 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1218 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1219 uint32_t inf_max_rt = ntohl_unaligned(odata);
1220 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1221 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1222 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1223 #ifdef EXT_CER_ID
1224 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1225 sizeof(struct dhcpv6_cer_id)) {
1226 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1227 struct in6_addr any = IN6ADDR_ANY_INIT;
1228 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1229 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1230 #endif
1231 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1232 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1233 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1234 size_t mape_len;
1235 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1236 if (mape_len == 0)
1237 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1238 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1239 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1240 } else
1241 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1242
1243 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1244 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1245 }
1246 }
1247
1248 // Bail out if fatal status code was received
1249 if (ret <= 0)
1250 return ret;
1251
1252 switch (orig) {
1253 case DHCPV6_MSG_REQUEST:
1254 case DHCPV6_MSG_REBIND:
1255 case DHCPV6_MSG_RENEW:
1256 state_IAs = dhcpv6_calc_refresh_timers();
1257 // In case there're no state IA entries
1258 // keep sending request/renew/rebind messages
1259 if (state_IAs == 0) {
1260 ret = 0;
1261 break;
1262 }
1263
1264 if (orig == DHCPV6_MSG_REQUEST) {
1265 // All server candidates can be cleared if not yet bound
1266 if (!odhcp6c_is_bound())
1267 dhcpv6_clear_all_server_cand();
1268
1269 odhcp6c_clear_state(STATE_SERVER_ADDR);
1270 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1271 } else if (orig == DHCPV6_MSG_RENEW) {
1272 // Send further renews if T1 is not set and if
1273 // there're IAs which were not in the Reply message
1274 if (!t1 && state_IAs != updated_IAs) {
1275 if (updated_IAs)
1276 // Publish updates
1277 script_call("updated", 0, false);
1278
1279 /*
1280 * RFC8415 states following in §18.2.10.1 :
1281 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1282 * message, but as this likely indicates that the server that
1283 * responded does not support that IA type, sending immediately is
1284 * unlikely to produce a different result. Therefore, the client
1285 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1286 * wait for the normal retransmission time (as if the Reply message
1287 * had not been received). The client continues to use other
1288 * bindings for which the server did return information
1289 */
1290 ret = -1;
1291 }
1292 } else if (orig == DHCPV6_MSG_REBIND) {
1293 odhcp6c_clear_state(STATE_SERVER_ADDR);
1294 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1295
1296 // Send further rebinds if T1 and T2 is not set and if
1297 // there're IAs which were not in the Reply message
1298 if (!t1 && !t2 && state_IAs != updated_IAs) {
1299 if (updated_IAs)
1300 // Publish updates
1301 script_call("updated", 0, false);
1302
1303 /*
1304 * RFC8415 states following in §18.2.10.1 :
1305 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1306 * message, but as this likely indicates that the server that
1307 * responded does not support that IA type, sending immediately is
1308 * unlikely to produce a different result. Therefore, the client
1309 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1310 * wait for the normal retransmission time (as if the Reply message
1311 * had not been received). The client continues to use other
1312 * bindings for which the server did return information
1313 */
1314 ret = -1;
1315 }
1316 }
1317 break;
1318
1319 case DHCPV6_MSG_INFO_REQ:
1320 // All server candidates can be cleared if not yet bound
1321 if (!odhcp6c_is_bound())
1322 dhcpv6_clear_all_server_cand();
1323
1324 t1 = refresh;
1325 break;
1326
1327 default:
1328 break;
1329 }
1330
1331 return ret;
1332 }
1333
1334 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1335 {
1336 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1337 unsigned int updated_IAs = 0;
1338 uint32_t t1, t2;
1339 uint16_t otype, olen;
1340 uint8_t *odata;
1341 char buf[INET6_ADDRSTRLEN];
1342
1343 t1 = ntohl(ia_hdr->t1);
1344 t2 = ntohl(ia_hdr->t2);
1345
1346 if (t1 > t2)
1347 return 0;
1348
1349 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);
1350
1351 // Update address IA
1352 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1353 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1354 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1355
1356 entry.iaid = ia_hdr->iaid;
1357
1358 if (otype == DHCPV6_OPT_IA_PREFIX) {
1359 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1360 if (olen + 4U < sizeof(*prefix))
1361 continue;
1362
1363 entry.valid = ntohl(prefix->valid);
1364 entry.preferred = ntohl(prefix->preferred);
1365
1366 if (entry.preferred > entry.valid)
1367 continue;
1368
1369 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1370 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1371 if (entry.t1 > entry.t2)
1372 entry.t1 = entry.t2;
1373
1374 entry.length = prefix->prefix;
1375 entry.target = prefix->addr;
1376 uint16_t stype, slen;
1377 uint8_t *sdata;
1378
1379 // Parse PD-exclude
1380 bool ok = true;
1381 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1382 odata + olen, stype, slen, sdata) {
1383 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1384 continue;
1385
1386 uint8_t elen = sdata[0];
1387 if (elen > 64)
1388 elen = 64;
1389
1390 if (entry.length < 32 || elen <= entry.length) {
1391 ok = false;
1392 continue;
1393 }
1394
1395 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1396 if (slen <= bytes) {
1397 ok = false;
1398 continue;
1399 }
1400
1401 uint32_t exclude = 0;
1402 do {
1403 exclude = exclude << 8 | sdata[bytes];
1404 } while (--bytes);
1405
1406 exclude >>= 8 - ((elen - entry.length) % 8);
1407 exclude <<= 64 - elen;
1408
1409 // Abusing router & priority fields for exclusion
1410 entry.router = entry.target;
1411 entry.router.s6_addr32[1] |= htonl(exclude);
1412 entry.priority = elen;
1413 }
1414
1415 if (ok) {
1416 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1417 updated_IAs++;
1418
1419 syslog(LOG_INFO, "%s/%d preferred %d valid %d",
1420 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1421 entry.length, entry.preferred , entry.valid);
1422 }
1423
1424 entry.priority = 0;
1425 memset(&entry.router, 0, sizeof(entry.router));
1426 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1427 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1428 if (olen + 4U < sizeof(*addr))
1429 continue;
1430
1431 entry.preferred = ntohl(addr->preferred);
1432 entry.valid = ntohl(addr->valid);
1433
1434 if (entry.preferred > entry.valid)
1435 continue;
1436
1437 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1438 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1439 if (entry.t1 > entry.t2)
1440 entry.t1 = entry.t2;
1441
1442 entry.length = 128;
1443 entry.target = addr->addr;
1444
1445 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1446 updated_IAs++;
1447
1448 syslog(LOG_INFO, "%s preferred %d valid %d",
1449 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1450 entry.preferred , entry.valid);
1451 }
1452 }
1453
1454 return updated_IAs;
1455 }
1456
1457 static unsigned int dhcpv6_calc_refresh_timers(void)
1458 {
1459 struct odhcp6c_entry *e;
1460 size_t ia_na_entries, ia_pd_entries, i;
1461 size_t invalid_entries = 0;
1462 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1463
1464 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1465 ia_na_entries /= sizeof(*e);
1466
1467 for (i = 0; i < ia_na_entries; i++) {
1468 /* Exclude invalid IA_NA entries */
1469 if (!e[i].valid) {
1470 invalid_entries++;
1471 continue;
1472 }
1473
1474 if (e[i].t1 < l_t1)
1475 l_t1 = e[i].t1;
1476
1477 if (e[i].t2 < l_t2)
1478 l_t2 = e[i].t2;
1479
1480 if (e[i].valid > l_t3)
1481 l_t3 = e[i].valid;
1482 }
1483
1484 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1485 ia_pd_entries /= sizeof(*e);
1486
1487 for (i = 0; i < ia_pd_entries; i++) {
1488 /* Exclude invalid IA_PD entries */
1489 if (!e[i].valid) {
1490 invalid_entries++;
1491 continue;
1492 }
1493
1494 if (e[i].t1 < l_t1)
1495 l_t1 = e[i].t1;
1496
1497 if (e[i].t2 < l_t2)
1498 l_t2 = e[i].t2;
1499
1500 if (e[i].valid > l_t3)
1501 l_t3 = e[i].valid;
1502 }
1503
1504 if (ia_pd_entries + ia_na_entries - invalid_entries) {
1505 t1 = l_t1;
1506 t2 = l_t2;
1507 t3 = l_t3;
1508
1509 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
1510 }
1511
1512 return (unsigned int)(ia_pd_entries + ia_na_entries);
1513 }
1514
1515 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1516 const void *status_msg, int len)
1517 {
1518 const char *src = status_msg;
1519 char buf[len + 3];
1520 char *dst = buf;
1521
1522 if (len) {
1523 *dst++ = '(';
1524 while (len--) {
1525 *dst = isprint((unsigned char)*src) ? *src : '?';
1526 src++;
1527 dst++;
1528 }
1529 *dst++ = ')';
1530 }
1531
1532 *dst = 0;
1533
1534 syslog(LOG_WARNING, "Server returned %s status '%s %s'",
1535 scope, dhcpv6_status_code_to_str(code), buf);
1536 }
1537
1538 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1539 const uint16_t code, const void *status_msg, const int len,
1540 int *ret)
1541 {
1542 dhcpv6_log_status_code(code, "message", status_msg, len);
1543
1544 switch (code) {
1545 case DHCPV6_UnspecFail:
1546 // Generic failure
1547 *ret = 0;
1548 break;
1549
1550 case DHCPV6_UseMulticast:
1551 switch(orig) {
1552 case DHCPV6_MSG_REQUEST:
1553 case DHCPV6_MSG_RENEW:
1554 case DHCPV6_MSG_RELEASE:
1555 case DHCPV6_MSG_DECLINE:
1556 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1557 server_addr = in6addr_any;
1558 *ret = 0;
1559 break;
1560 default:
1561 break;
1562 }
1563 break;
1564
1565 case DHCPV6_NoAddrsAvail:
1566 case DHCPV6_NoPrefixAvail:
1567 if (orig == DHCPV6_MSG_REQUEST)
1568 *ret = 0; // Failure
1569 break;
1570
1571 default:
1572 break;
1573 }
1574 }
1575
1576 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1577 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1578 const void *status_msg, const int len,
1579 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1580 {
1581 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1582 "IA_NA" : "IA_PD", status_msg, len);
1583
1584 switch (code) {
1585 case DHCPV6_NoBinding:
1586 switch (orig) {
1587 case DHCPV6_MSG_RENEW:
1588 case DHCPV6_MSG_REBIND:
1589 if ((*ret > 0) && !handled_status_codes[code])
1590 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1591 break;
1592
1593 default:
1594 break;
1595 }
1596 break;
1597
1598 default:
1599 *ret = 0;
1600 break;
1601 }
1602 }
1603
1604 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1605 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1606 {
1607 size_t cand_len, i;
1608 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1609
1610 // Remove identical duid server candidate
1611 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1612 if (cand->duid_len == c[i].duid_len &&
1613 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1614 free(c[i].ia_na);
1615 free(c[i].ia_pd);
1616 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1617 break;
1618 }
1619 }
1620
1621 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1622 i < cand_len / sizeof(*c); ++i) {
1623 if (c[i].preference < cand->preference)
1624 break;
1625 }
1626
1627 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1628 free(cand->ia_na);
1629 free(cand->ia_pd);
1630 }
1631 }
1632
1633 static void dhcpv6_clear_all_server_cand(void)
1634 {
1635 size_t cand_len, i;
1636 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1637
1638 // Server candidates need deep delete for IA_NA/IA_PD
1639 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1640 free(c[i].ia_na);
1641 free(c[i].ia_pd);
1642 }
1643 odhcp6c_clear_state(STATE_SERVER_CAND);
1644 }
1645
1646 int dhcpv6_promote_server_cand(void)
1647 {
1648 size_t cand_len;
1649 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1650 uint16_t hdr[2];
1651 int ret = DHCPV6_STATELESS;
1652
1653 // Clear lingering candidate state info
1654 odhcp6c_clear_state(STATE_SERVER_ID);
1655 odhcp6c_clear_state(STATE_IA_NA);
1656 odhcp6c_clear_state(STATE_IA_PD);
1657
1658 if (!cand_len)
1659 return -1;
1660
1661 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1662 na_mode = IA_MODE_NONE;
1663
1664 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1665 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1666
1667 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1668 }
1669
1670 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1671 hdr[1] = htons(cand->duid_len);
1672 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1673 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1674 accept_reconfig = cand->wants_reconfigure;
1675
1676 if (cand->ia_na_len) {
1677 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1678 free(cand->ia_na);
1679 if (na_mode != IA_MODE_NONE)
1680 ret = DHCPV6_STATEFUL;
1681 }
1682
1683 if (cand->ia_pd_len) {
1684 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1685 free(cand->ia_pd);
1686 if (pd_mode != IA_MODE_NONE)
1687 ret = DHCPV6_STATEFUL;
1688 }
1689
1690 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1691 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1692
1693 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1694
1695 return ret;
1696 }
Openwrt DHCPv6 Client