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[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15 #include <time.h>
16 #include <fcntl.h>
17 #include <errno.h>
18 #include <stdlib.h>
19 #include <signal.h>
20 #include <limits.h>
21 #include <resolv.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <syslog.h>
25 #include <stdbool.h>
26 #include <sys/time.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30
31 #include <net/if.h>
32 #include <net/ethernet.h>
33
34 #include "odhcp6c.h"
35 #include "md5.h"
36
37
38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
39 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
40 #define DHCPV6_CLIENT_PORT 546
41 #define DHCPV6_SERVER_PORT 547
42 #define DHCPV6_DUID_LLADDR 3
43 #define DHCPV6_REQ_DELAY 1
44
45
46 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
47 const uint8_t transaction[3], enum dhcpv6_msg type);
48
49 static uint32_t dhcpv6_parse_ia(void *opt, void *end);
50
51 static reply_handler dhcpv6_handle_reply;
52 static reply_handler dhcpv6_handle_advert;
53 static reply_handler dhcpv6_handle_rebind_reply;
54 static reply_handler dhcpv6_handle_reconfigure;
55 static int dhcpv6_commit_advert(void);
56
57
58
59 // RFC 3315 - 5.5 Timeout and Delay values
60 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
61 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, "<POLL>",
62 dhcpv6_handle_reconfigure, NULL},
63 [DHCPV6_MSG_SOLICIT] = {true, 1, 3600, "SOLICIT",
64 dhcpv6_handle_advert, dhcpv6_commit_advert},
65 [DHCPV6_MSG_REQUEST] = {true, 30, 10, "REQUEST",
66 dhcpv6_handle_reply, NULL},
67 [DHCPV6_MSG_RENEW] = {false, 10, 600, "RENEW",
68 dhcpv6_handle_reply, NULL},
69 [DHCPV6_MSG_REBIND] = {false, 10, 600, "REBIND",
70 dhcpv6_handle_rebind_reply, NULL},
71 [DHCPV6_MSG_RELEASE] = {false, 1, 600, "RELEASE", NULL, NULL},
72 [DHCPV6_MSG_DECLINE] = {false, 1, 3, "DECLINE", NULL, NULL},
73 [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, "INFOREQ",
74 dhcpv6_handle_reply, NULL},
75 };
76
77
78 // Sockets
79 static int sock = -1;
80 static int ifindex = -1;
81 static int64_t t1 = 0, t2 = 0, t3 = 0;
82
83 // IA states
84 static int request_prefix = -1;
85 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE;
86 static bool accept_reconfig = false;
87
88 // Reconfigure key
89 static uint8_t reconf_key[16];
90
91
92
93 int init_dhcpv6(const char *ifname, int request_pd)
94 {
95 request_prefix = request_pd;
96
97 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
98
99 // Detect interface
100 struct ifreq ifr;
101 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
102 if (ioctl(sock, SIOCGIFINDEX, &ifr))
103 return -1;
104 ifindex = ifr.ifr_ifindex;
105
106 // Create client DUID
107 size_t client_id_len;
108 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
109 if (client_id_len == 0) {
110 ioctl(sock, SIOCGIFHWADDR, &ifr);
111 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
112 DHCPV6_DUID_LLADDR, 0, 1};
113 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
114
115 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
116 struct ifreq ifs[100], *ifp, *ifend;
117 struct ifconf ifc;
118 ifc.ifc_req = ifs;
119 ifc.ifc_len = sizeof(ifs);
120
121 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
122 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
123 // If our interface doesn't have an address...
124 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
125 for (ifp = ifc.ifc_req; ifp < ifend &&
126 !memcmp(&duid[8], zero, 6); ifp++) {
127 memcpy(ifr.ifr_name, ifp->ifr_name,
128 sizeof(ifr.ifr_name));
129 ioctl(sock, SIOCGIFHWADDR, &ifr);
130 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
131 ETHER_ADDR_LEN);
132 }
133 }
134
135 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
136 }
137
138 // Create ORO
139 uint16_t oro[] = {
140 htons(DHCPV6_OPT_SIP_SERVER_D),
141 htons(DHCPV6_OPT_SIP_SERVER_A),
142 htons(DHCPV6_OPT_DNS_SERVERS),
143 htons(DHCPV6_OPT_DNS_DOMAIN),
144 htons(DHCPV6_OPT_NTP_SERVER),
145 htons(DHCPV6_OPT_AFTR_NAME),
146 htons(DHCPV6_OPT_PD_EXCLUDE),
147 };
148 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
149
150
151 // Configure IPv6-options
152 int val = 1;
153 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
154 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
155 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
156
157 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
158 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
159 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
160 return -1;
161
162 return 0;
163 }
164
165
166 void dhcpv6_set_ia_na_mode(enum odhcp6c_ia_mode mode)
167 {
168 na_mode = mode;
169 }
170
171
172 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
173 {
174 // Build FQDN
175 char fqdn_buf[256];
176 gethostname(fqdn_buf, sizeof(fqdn_buf));
177 struct {
178 uint16_t type;
179 uint16_t len;
180 uint8_t flags;
181 uint8_t data[256];
182 } fqdn;
183 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
184 sizeof(fqdn.data), NULL, NULL);
185 fqdn.type = htons(DHCPV6_OPT_FQDN);
186 fqdn.len = htons(fqdn_len - 4);
187 fqdn.flags = 0;
188
189
190 // Build Client ID
191 size_t cl_id_len;
192 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
193
194 // Get Server ID
195 size_t srv_id_len;
196 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
197
198 // Build IA_PDs
199 size_t ia_pd_entries, ia_pd_len = 0;
200 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
201 ia_pd_entries /= sizeof(*e);
202 struct dhcpv6_ia_hdr hdr_ia_pd = {
203 htons(DHCPV6_OPT_IA_PD),
204 htons(sizeof(hdr_ia_pd) - 4),
205 1, 0, 0
206 };
207
208
209 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
210 for (size_t i = 0; i < ia_pd_entries; ++i) {
211 uint8_t ex_len = 0;
212 if (e[i].priority > 0)
213 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
214
215 struct dhcpv6_ia_prefix p = {
216 .type = htons(DHCPV6_OPT_IA_PREFIX),
217 .len = htons(sizeof(p) - 4U + ex_len),
218 .prefix = e[i].length,
219 .addr = e[i].target
220 };
221
222 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
223 ia_pd_len += sizeof(p);
224
225 if (ex_len) {
226 ia_pd[ia_pd_len++] = 0;
227 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
228 ia_pd[ia_pd_len++] = 0;
229 ia_pd[ia_pd_len++] = ex_len - 4;
230 ia_pd[ia_pd_len++] = e[i].priority;
231
232 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
233 excl >>= (64 - e[i].priority);
234 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
235
236 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
237 ia_pd[ia_pd_len + i] = excl & 0xff;
238 ia_pd_len += ex_len - 5;
239 }
240 }
241
242 struct dhcpv6_ia_prefix pref = {
243 .type = htons(DHCPV6_OPT_IA_PREFIX),
244 .len = htons(25), .prefix = request_prefix
245 };
246 if (request_prefix > 0 && ia_pd_len == 0 &&
247 (type == DHCPV6_MSG_SOLICIT ||
248 type == DHCPV6_MSG_REQUEST)) {
249 ia_pd = (uint8_t*)&pref;
250 ia_pd_len = sizeof(pref);
251 }
252 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
253
254 // Build IA_NAs
255 size_t ia_na_entries, ia_na_len = 0;
256 void *ia_na = NULL;
257 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
258 ia_na_entries /= sizeof(*e);
259
260 struct dhcpv6_ia_hdr hdr_ia_na = {
261 htons(DHCPV6_OPT_IA_NA),
262 htons(sizeof(hdr_ia_na) - 4),
263 1, 0, 0
264 };
265
266 struct dhcpv6_ia_addr pa[ia_na_entries];
267 for (size_t i = 0; i < ia_na_entries; ++i) {
268 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
269 pa[i].len = htons(sizeof(pa[i]) - 4U);
270 pa[i].addr = e[i].target;
271 pa[i].preferred = 0;
272 pa[i].valid = 0;
273 }
274
275 ia_na = pa;
276 ia_na_len = sizeof(pa);
277 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
278
279 // Reconfigure Accept
280 struct {
281 uint16_t type;
282 uint16_t length;
283 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
284
285 // Request Information Refresh
286 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
287
288 // Prepare Header
289 size_t oro_len;
290 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
291 struct {
292 uint8_t type;
293 uint8_t trid[3];
294 uint16_t elapsed_type;
295 uint16_t elapsed_len;
296 uint16_t elapsed_value;
297 uint16_t oro_type;
298 uint16_t oro_len;
299 } hdr = {
300 type, {trid[0], trid[1], trid[2]},
301 htons(DHCPV6_OPT_ELAPSED), htons(2),
302 htons((ecs > 0xffff) ? 0xffff : ecs),
303 htons(DHCPV6_OPT_ORO), htons(oro_len),
304 };
305
306 struct iovec iov[] = {
307 {&hdr, sizeof(hdr)},
308 {oro, oro_len},
309 {&oro_refresh, 0},
310 {cl_id, cl_id_len},
311 {srv_id, srv_id_len},
312 {&reconf_accept, sizeof(reconf_accept)},
313 {&fqdn, fqdn_len},
314 {&hdr_ia_na, sizeof(hdr_ia_na)},
315 {ia_na, ia_na_len},
316 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
317 {ia_pd, ia_pd_len},
318 };
319
320 size_t cnt = ARRAY_SIZE(iov);
321 if (type == DHCPV6_MSG_INFO_REQ) {
322 cnt = 5;
323 iov[2].iov_len = sizeof(oro_refresh);
324 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
325 } else if (!request_prefix) {
326 cnt = 9;
327 }
328
329 // Disable IAs if not used
330 if (type != DHCPV6_MSG_REQUEST && type != DHCPV6_MSG_SOLICIT) {
331 iov[5].iov_len = 0;
332 if (ia_na_len == 0)
333 iov[7].iov_len = 0;
334 if (ia_pd_len == 0)
335 iov[9].iov_len = 0;
336 }
337
338 if (na_mode == IA_MODE_NONE)
339 iov[7].iov_len = 0;
340
341 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
342 0, ALL_DHCPV6_RELAYS, ifindex};
343 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
344
345 sendmsg(sock, &msg, 0);
346 }
347
348
349 static int64_t dhcpv6_rand_delay(int64_t time)
350 {
351 int random;
352 odhcp6c_random(&random, sizeof(random));
353 return (time * (random % 1000)) / 10000;
354 }
355
356
357 int dhcpv6_request(enum dhcpv6_msg type)
358 {
359 uint8_t buf[1536];
360 uint32_t timeout = UINT32_MAX;
361 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
362
363 if (retx->delay) {
364 struct timespec ts = {0, 0};
365 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
366 nanosleep(&ts, NULL);
367 }
368
369 if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
370 timeout = 3;
371 else if (type == DHCPV6_MSG_UNKNOWN)
372 timeout = t1;
373 else if (type == DHCPV6_MSG_RENEW)
374 timeout = t2 - t1;
375 else if (type == DHCPV6_MSG_REBIND)
376 timeout = t3 - t2;
377
378 if (timeout == 0)
379 return -1;
380
381 syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, timeout);
382
383 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
384
385 // Generate transaction ID
386 uint8_t trid[3] = {0, 0, 0};
387 if (type != DHCPV6_MSG_UNKNOWN)
388 odhcp6c_random(trid, sizeof(trid));
389 ssize_t len = -1;
390 int64_t rto = 0;
391
392 do {
393 rto = (rto == 0) ? (retx->init_timeo * 1000 +
394 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
395 (2 * rto + dhcpv6_rand_delay(rto));
396
397 if (rto >= retx->max_timeo * 1000)
398 rto = retx->max_timeo * 1000 +
399 dhcpv6_rand_delay(retx->max_timeo * 1000);
400
401 // Calculate end for this round and elapsed time
402 uint64_t round_end = round_start + rto;
403 elapsed = round_start - start;
404
405 // Don't wait too long
406 if (round_end - start > timeout * 1000)
407 round_end = timeout * 1000 + start;
408
409 // Built and send package
410 if (type != DHCPV6_MSG_UNKNOWN)
411 dhcpv6_send(type, trid, elapsed / 10);
412
413 // Receive rounds
414 for (; len < 0 && round_start < round_end;
415 round_start = odhcp6c_get_milli_time()) {
416 // Check for pending signal
417 if (odhcp6c_signal_process())
418 return -1;
419
420 // Set timeout for receiving
421 uint64_t t = round_end - round_start;
422 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
423 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
424 &timeout, sizeof(timeout));
425
426 // Receive cycle
427 len = recv(sock, buf, sizeof(buf), 0);
428
429 if (!dhcpv6_response_is_valid(buf, len, trid, type))
430 len = -1;
431
432 if (len > 0) {
433 uint8_t *opt = &buf[4];
434 uint8_t *opt_end = opt + len - 4;
435
436 round_start = odhcp6c_get_milli_time();
437 elapsed = round_start - start;
438 syslog(LOG_NOTICE, "Got a valid reply after "
439 "%ums", (unsigned)elapsed);
440
441 if (retx->handler_reply)
442 len = retx->handler_reply(
443 type, opt, opt_end);
444
445 if (round_end - round_start > 1000)
446 round_end = 1000 + round_start;
447 }
448 }
449
450 // Allow
451 if (retx->handler_finish)
452 len = retx->handler_finish();
453 } while (len < 0 && elapsed / 1000 < timeout);
454
455 return len;
456 }
457
458
459 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
460 const uint8_t transaction[3], enum dhcpv6_msg type)
461 {
462 const struct dhcpv6_header *rep = buf;
463 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
464 transaction, sizeof(rep->tr_id)))
465 return false; // Invalid reply
466
467 if (type == DHCPV6_MSG_SOLICIT) {
468 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
469 rep->msg_type != DHCPV6_MSG_REPLY)
470 return false;
471 } else if (type == DHCPV6_MSG_UNKNOWN) {
472 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
473 return false;
474 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
475 return false;
476 }
477
478 uint8_t *end = ((uint8_t*)buf) + len, *odata;
479 uint16_t otype, olen;
480 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
481
482 size_t client_id_len, server_id_len;
483 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
484 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
485
486 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
487 if (otype == DHCPV6_OPT_CLIENTID) {
488 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
489 &odata[-4], client_id, client_id_len);
490 } else if (otype == DHCPV6_OPT_SERVERID) {
491 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
492 &odata[-4], server_id, server_id_len);
493 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
494 sizeof(struct dhcpv6_auth_reconfigure)) {
495 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
496 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
497 continue;
498
499 md5_state_t md5;
500 uint8_t serverhash[16], secretbytes[16], hash[16];
501 memcpy(serverhash, r->key, sizeof(serverhash));
502 memset(r->key, 0, sizeof(r->key));
503 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
504
505 for (size_t i = 0; i < sizeof(secretbytes); ++i)
506 secretbytes[i] ^= 0x36;
507
508 md5_init(&md5);
509 md5_append(&md5, secretbytes, sizeof(secretbytes));
510 md5_append(&md5, buf, len);
511 md5_finish(&md5, hash);
512
513 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
514 secretbytes[i] ^= 0x36;
515 secretbytes[i] ^= 0x5c;
516 }
517
518 md5_init(&md5);
519 md5_append(&md5, secretbytes, sizeof(secretbytes));
520 md5_append(&md5, hash, 16);
521 md5_finish(&md5, hash);
522
523 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
524 }
525 }
526
527 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
528 return false;
529
530 return clientid_ok && (serverid_ok || server_id_len == 0);
531 }
532
533
534 int dhcpv6_poll_reconfigure(void)
535 {
536 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
537 if (ret != -1)
538 ret = dhcpv6_request(ret);
539
540 return ret;
541 }
542
543
544 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
545 const void *opt, const void *end)
546 {
547 // TODO: should verify the reconfigure message
548 uint16_t otype, olen;
549 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
550 dhcpv6_for_each_option(opt, end, otype, olen, odata)
551 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
552 odata[0] == DHCPV6_MSG_RENEW ||
553 odata[0] == DHCPV6_MSG_INFO_REQ))
554 msg = odata[0];
555
556 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
557 return msg;
558 }
559
560
561 // Collect all advertised servers
562 static int dhcpv6_handle_advert(_unused enum dhcpv6_msg orig,
563 const void *opt, const void *end)
564 {
565 uint16_t olen, otype;
566 uint8_t *odata;
567 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}};
568
569 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
570 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
571 memcpy(cand.duid, odata, olen);
572 cand.duid_len = olen;
573 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
574 && odata[1] == DHCPV6_NoAddrsAvail) {
575 if (na_mode == IA_MODE_FORCE) {
576 return -1;
577 } else {
578 cand.has_noaddravail = true;
579 cand.preference -= 1000;
580 }
581 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
582 && odata[1] == DHCPV6_NoPrefixAvail) {
583 cand.preference -= 2000;
584 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
585 cand.preference >= 0) {
586 cand.preference = odata[0];
587 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
588 cand.wants_reconfigure = true;
589 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
590 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
591 uint8_t *oend = odata + olen, *d;
592 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
593 if (otype == DHCPV6_OPT_IA_PREFIX)
594 cand.preference += 2000;
595 else if (otype == DHCPV6_OPT_STATUS &&
596 olen >= 2 && d[0] == 0 &&
597 d[1] == DHCPV6_NoPrefixAvail)
598 cand.preference -= 2000;
599 }
600 }
601 }
602
603 if (cand.duid_len > 0)
604 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
605
606 return -1;
607 }
608
609
610 static int dhcpv6_commit_advert(void)
611 {
612 size_t cand_len;
613 struct dhcpv6_server_cand *c = NULL, *cand =
614 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
615
616 bool retry = false;
617 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
618 if (cand[i].has_noaddravail)
619 retry = true; // We want to try again
620
621 if (!c || c->preference < cand[i].preference)
622 c = &cand[i];
623 }
624
625 if (retry && na_mode == IA_MODE_TRY) {
626 // We give it a second try without the IA_NA
627 na_mode = IA_MODE_NONE;
628 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
629 }
630
631 if (c) {
632 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
633 htons(c->duid_len)};
634 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
635 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
636 accept_reconfig = c->wants_reconfigure;
637 }
638
639 odhcp6c_clear_state(STATE_SERVER_CAND);
640
641 if (!c)
642 return -1;
643 else if (request_prefix || na_mode != IA_MODE_NONE)
644 return DHCPV6_STATEFUL;
645 else
646 return DHCPV6_STATELESS;
647 }
648
649
650 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
651 const void *opt, const void *end)
652 {
653 dhcpv6_handle_advert(orig, opt, end);
654 if (dhcpv6_commit_advert() < 0) {
655 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
656 return -1;
657 }
658
659 return dhcpv6_handle_reply(orig, opt, end);
660 }
661
662
663 static int dhcpv6_handle_reply(enum dhcpv6_msg orig,
664 const void *opt, const void *end)
665 {
666 uint8_t *odata;
667 uint16_t otype, olen;
668
669 odhcp6c_expire();
670
671 if (orig == DHCPV6_MSG_UNKNOWN) {
672 static time_t last_update = 0;
673 time_t now = odhcp6c_get_milli_time() / 1000;
674
675 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
676 last_update = now;
677
678 t1 -= elapsed;
679 t2 -= elapsed;
680 t3 -= elapsed;
681
682 if (t1 < 0)
683 t1 = 0;
684
685 if (t2 < 0)
686 t2 = 0;
687
688 if (t3 < 0)
689 t3 = 0;
690 } else {
691 t1 = t2 = t3 = UINT32_MAX;
692 }
693
694 if (opt) {
695 odhcp6c_clear_state(STATE_DNS);
696 odhcp6c_clear_state(STATE_SEARCH);
697 odhcp6c_clear_state(STATE_SNTP_IP);
698 odhcp6c_clear_state(STATE_SNTP_FQDN);
699 odhcp6c_clear_state(STATE_SIP_IP);
700 odhcp6c_clear_state(STATE_SIP_FQDN);
701 odhcp6c_clear_state(STATE_AFTR_NAME);
702 }
703
704 // Parse and find all matching IAs
705 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
706 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
707 && olen > sizeof(struct dhcpv6_ia_hdr)) {
708 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
709 uint32_t l_t1 = ntohl(ia_hdr->t1);
710 uint32_t l_t2 = ntohl(ia_hdr->t2);
711
712 // Test ID and T1-T2 validity
713 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
714 continue;
715
716 bool error = false;
717 uint16_t stype, slen;
718 uint8_t *sdata;
719 // Test status and bail if error
720 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
721 stype, slen, sdata)
722 if (stype == DHCPV6_OPT_STATUS && slen >= 2 &&
723 (sdata[0] || sdata[1]))
724 error = true;
725
726 if (error)
727 continue;
728
729 // Update times
730 if (l_t1 > 0 && t1 > l_t1)
731 t1 = l_t1;
732
733 if (l_t2 > 0 && t2 > l_t2)
734 t2 = l_t2;
735
736 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
737
738 if (n < t1)
739 t1 = n;
740
741 if (n < t2)
742 t2 = n;
743
744 if (n < t3)
745 t3 = n;
746
747 if (t2 >= t3)
748 t2 = 8 * t3 / 10;
749
750 if (t1 >= t2)
751 t1 = 5 * t2 / 8;
752
753 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
754 if (olen % 16 == 0)
755 odhcp6c_add_state(STATE_DNS, odata, olen);
756 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
757 odhcp6c_add_state(STATE_SEARCH, odata, olen);
758 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
759 uint16_t stype, slen;
760 uint8_t *sdata;
761 // Test status and bail if error
762 dhcpv6_for_each_option(odata, odata + olen,
763 stype, slen, sdata) {
764 if (slen == 16 && (stype == NTP_MC_ADDR ||
765 stype == NTP_SRV_ADDR))
766 odhcp6c_add_state(STATE_SNTP_IP,
767 sdata, slen);
768 else if (slen > 0 && stype == NTP_SRV_FQDN)
769 odhcp6c_add_state(STATE_SNTP_FQDN,
770 sdata, slen);
771 }
772 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
773 if (olen == 16)
774 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
775 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
776 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
777 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
778 uint32_t refresh = ntohl(*((uint32_t*)odata));
779 if (refresh < (uint32_t)t1)
780 t1 = refresh;
781 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
782 sizeof(struct dhcpv6_auth_reconfigure)) {
783 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
784 if (r->protocol == 3 && r->algorithm == 1 &&
785 r->reconf_type == 1)
786 memcpy(reconf_key, r->key, sizeof(r->key));
787 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
788 size_t cur_len;
789 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
790 if (cur_len == 0)
791 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
792 } else if (otype != DHCPV6_OPT_CLIENTID &&
793 otype != DHCPV6_OPT_SERVERID) {
794 odhcp6c_add_state(STATE_CUSTOM_OPTS,
795 &odata[-4], olen + 4);
796 }
797 }
798
799 return true;
800 }
801
802
803 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
804 {
805 uint32_t timeout = UINT32_MAX; // Minimum timeout
806 uint16_t otype, olen;
807 uint8_t *odata;
808
809 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT,
810 0, 0, IN6ADDR_ANY_INIT, 0, 0};
811
812 // Update address IA
813 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
814 if (otype == DHCPV6_OPT_IA_PREFIX) {
815 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
816 if (olen + 4U < sizeof(*prefix))
817 continue;
818
819 entry.valid = ntohl(prefix->valid);
820 entry.preferred = ntohl(prefix->preferred);
821
822 if (entry.preferred > entry.valid)
823 continue;
824
825 entry.length = prefix->prefix;
826 entry.target = prefix->addr;
827
828 // Parse PD-exclude
829 bool ok = true;
830 uint16_t stype, slen;
831 uint8_t *sdata;
832 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
833 odata + olen, stype, slen, sdata) {
834 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
835 continue;
836
837 uint8_t elen = sdata[0];
838 if (elen > 64)
839 elen = 64;
840
841 if (elen <= 32 || elen <= entry.length) {
842 ok = false;
843 continue;
844 }
845
846
847 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
848 if (slen <= bytes) {
849 ok = false;
850 continue;
851 }
852
853 uint32_t exclude = 0;
854 do {
855 exclude = exclude << 8 | sdata[bytes];
856 } while (--bytes);
857
858 exclude >>= 8 - ((elen - entry.length) % 8);
859 exclude <<= 64 - elen;
860
861 // Abusing router & priority fields for exclusion
862 entry.router = entry.target;
863 entry.router.s6_addr32[1] |= htonl(exclude);
864 entry.priority = elen;
865 }
866
867 if (ok)
868 odhcp6c_update_entry(STATE_IA_PD, &entry);
869
870 entry.priority = 0;
871 memset(&entry.router, 0, sizeof(entry.router));
872 } else if (otype == DHCPV6_OPT_IA_ADDR) {
873 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
874 if (olen + 4U < sizeof(*addr))
875 continue;
876
877 entry.preferred = ntohl(addr->preferred);
878 entry.valid = ntohl(addr->valid);
879
880 if (entry.preferred > entry.valid)
881 continue;
882
883 entry.length = 128;
884 entry.target = addr->addr;
885
886 odhcp6c_update_entry(STATE_IA_NA, &entry);
887 }
888
889 if (entry.valid > 0 && timeout > entry.valid)
890 timeout = entry.valid;
891 }
892
893 return timeout;
894 }
Openwrt DHCPv6 Client