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