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Merge preliminary prefix class support
[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_SIP_SERVER_A),
146 htons(DHCPV6_OPT_AFTR_NAME),
147 htons(DHCPV6_OPT_PD_EXCLUDE),
148 #ifdef EXT_PREFIX_CLASS
149 htons(DHCPV6_OPT_PREFIX_CLASS),
150 #endif
151 };
152 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
153
154
155 // Configure IPv6-options
156 int val = 1;
157 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
158 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
159 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
160
161 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
162 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
163 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
164 return -1;
165
166 return 0;
167 }
168
169
170 void dhcpv6_set_ia_na_mode(enum odhcp6c_ia_mode mode)
171 {
172 na_mode = mode;
173 }
174
175
176 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
177 {
178 // Build FQDN
179 char fqdn_buf[256];
180 gethostname(fqdn_buf, sizeof(fqdn_buf));
181 struct {
182 uint16_t type;
183 uint16_t len;
184 uint8_t flags;
185 uint8_t data[256];
186 } fqdn;
187 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
188 sizeof(fqdn.data), NULL, NULL);
189 fqdn.type = htons(DHCPV6_OPT_FQDN);
190 fqdn.len = htons(fqdn_len - 4);
191 fqdn.flags = 0;
192
193
194 // Build Client ID
195 size_t cl_id_len;
196 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
197
198 // Get Server ID
199 size_t srv_id_len;
200 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
201
202 // Build IA_PDs
203 size_t ia_pd_entries, ia_pd_len = 0;
204 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
205 ia_pd_entries /= sizeof(*e);
206 struct dhcpv6_ia_hdr hdr_ia_pd = {
207 htons(DHCPV6_OPT_IA_PD),
208 htons(sizeof(hdr_ia_pd) - 4),
209 1, 0, 0
210 };
211
212
213 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
214 for (size_t i = 0; i < ia_pd_entries; ++i) {
215 uint8_t ex_len = 0;
216 if (e[i].priority > 0)
217 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
218
219 struct dhcpv6_ia_prefix p = {
220 .type = htons(DHCPV6_OPT_IA_PREFIX),
221 .len = htons(sizeof(p) - 4U + ex_len),
222 .prefix = e[i].length,
223 .addr = e[i].target
224 };
225
226 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
227 ia_pd_len += sizeof(p);
228
229 if (ex_len) {
230 ia_pd[ia_pd_len++] = 0;
231 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
232 ia_pd[ia_pd_len++] = 0;
233 ia_pd[ia_pd_len++] = ex_len - 4;
234 ia_pd[ia_pd_len++] = e[i].priority;
235
236 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
237 excl >>= (64 - e[i].priority);
238 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
239
240 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
241 ia_pd[ia_pd_len + i] = excl & 0xff;
242 ia_pd_len += ex_len - 5;
243 }
244 }
245
246 struct dhcpv6_ia_prefix pref = {
247 .type = htons(DHCPV6_OPT_IA_PREFIX),
248 .len = htons(25), .prefix = request_prefix
249 };
250 if (request_prefix > 0 && ia_pd_len == 0 &&
251 (type == DHCPV6_MSG_SOLICIT ||
252 type == DHCPV6_MSG_REQUEST)) {
253 ia_pd = (uint8_t*)&pref;
254 ia_pd_len = sizeof(pref);
255 }
256 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
257
258 // Build IA_NAs
259 size_t ia_na_entries, ia_na_len = 0;
260 void *ia_na = NULL;
261 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
262 ia_na_entries /= sizeof(*e);
263
264 struct dhcpv6_ia_hdr hdr_ia_na = {
265 htons(DHCPV6_OPT_IA_NA),
266 htons(sizeof(hdr_ia_na) - 4),
267 1, 0, 0
268 };
269
270 struct dhcpv6_ia_addr pa[ia_na_entries];
271 for (size_t i = 0; i < ia_na_entries; ++i) {
272 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
273 pa[i].len = htons(sizeof(pa[i]) - 4U);
274 pa[i].addr = e[i].target;
275 pa[i].preferred = 0;
276 pa[i].valid = 0;
277 }
278
279 ia_na = pa;
280 ia_na_len = sizeof(pa);
281 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
282
283 // Reconfigure Accept
284 struct {
285 uint16_t type;
286 uint16_t length;
287 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
288
289 // Request Information Refresh
290 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
291
292 // Prepare Header
293 size_t oro_len;
294 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
295 struct {
296 uint8_t type;
297 uint8_t trid[3];
298 uint16_t elapsed_type;
299 uint16_t elapsed_len;
300 uint16_t elapsed_value;
301 uint16_t oro_type;
302 uint16_t oro_len;
303 } hdr = {
304 type, {trid[0], trid[1], trid[2]},
305 htons(DHCPV6_OPT_ELAPSED), htons(2),
306 htons((ecs > 0xffff) ? 0xffff : ecs),
307 htons(DHCPV6_OPT_ORO), htons(oro_len),
308 };
309
310 struct iovec iov[] = {
311 {&hdr, sizeof(hdr)},
312 {oro, oro_len},
313 {&oro_refresh, 0},
314 {cl_id, cl_id_len},
315 {srv_id, srv_id_len},
316 {&reconf_accept, sizeof(reconf_accept)},
317 {&fqdn, fqdn_len},
318 {&hdr_ia_na, sizeof(hdr_ia_na)},
319 {ia_na, ia_na_len},
320 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
321 {ia_pd, ia_pd_len},
322 };
323
324 size_t cnt = ARRAY_SIZE(iov);
325 if (type == DHCPV6_MSG_INFO_REQ) {
326 cnt = 5;
327 iov[2].iov_len = sizeof(oro_refresh);
328 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
329 } else if (!request_prefix) {
330 cnt = 9;
331 }
332
333 // Disable IAs if not used
334 if (type != DHCPV6_MSG_REQUEST && type != DHCPV6_MSG_SOLICIT) {
335 iov[5].iov_len = 0;
336 if (ia_na_len == 0)
337 iov[7].iov_len = 0;
338 if (ia_pd_len == 0)
339 iov[9].iov_len = 0;
340 }
341
342 if (na_mode == IA_MODE_NONE)
343 iov[7].iov_len = 0;
344
345 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
346 0, ALL_DHCPV6_RELAYS, ifindex};
347 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
348
349 sendmsg(sock, &msg, 0);
350 }
351
352
353 static int64_t dhcpv6_rand_delay(int64_t time)
354 {
355 int random;
356 odhcp6c_random(&random, sizeof(random));
357 return (time * ((int64_t)random % 1000LL)) / 10000LL;
358 }
359
360
361 int dhcpv6_request(enum dhcpv6_msg type)
362 {
363 uint8_t buf[1536];
364 uint64_t timeout = UINT32_MAX;
365 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
366
367 if (retx->delay) {
368 struct timespec ts = {0, 0};
369 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
370 nanosleep(&ts, NULL);
371 }
372
373 if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
374 timeout = 3;
375 else if (type == DHCPV6_MSG_UNKNOWN)
376 timeout = t1;
377 else if (type == DHCPV6_MSG_RENEW)
378 timeout = (t2 > t1) ? t2 - t1 : 0;
379 else if (type == DHCPV6_MSG_REBIND)
380 timeout = (t3 > t2) ? t3 - t2 : 0;
381
382 if (timeout == 0)
383 return -1;
384
385 syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, (unsigned)timeout);
386
387 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
388
389 // Generate transaction ID
390 uint8_t trid[3] = {0, 0, 0};
391 if (type != DHCPV6_MSG_UNKNOWN)
392 odhcp6c_random(trid, sizeof(trid));
393 ssize_t len = -1;
394 int64_t rto = 0;
395
396 do {
397 rto = (rto == 0) ? (retx->init_timeo * 1000 +
398 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
399 (2 * rto + dhcpv6_rand_delay(rto));
400
401 if (rto >= retx->max_timeo * 1000)
402 rto = retx->max_timeo * 1000 +
403 dhcpv6_rand_delay(retx->max_timeo * 1000);
404
405 // Calculate end for this round and elapsed time
406 uint64_t round_end = round_start + rto;
407 elapsed = round_start - start;
408
409 // Don't wait too long
410 if (round_end - start > timeout * 1000)
411 round_end = timeout * 1000 + start;
412
413 // Built and send package
414 if (type != DHCPV6_MSG_UNKNOWN)
415 dhcpv6_send(type, trid, elapsed / 10);
416
417 // Receive rounds
418 for (; len < 0 && round_start < round_end;
419 round_start = odhcp6c_get_milli_time()) {
420 // Check for pending signal
421 if (odhcp6c_signal_process())
422 return -1;
423
424 // Set timeout for receiving
425 uint64_t t = round_end - round_start;
426 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
427 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
428 &timeout, sizeof(timeout));
429
430 // Receive cycle
431 len = recv(sock, buf, sizeof(buf), 0);
432
433 if (!dhcpv6_response_is_valid(buf, len, trid, type))
434 len = -1;
435
436 if (len > 0) {
437 uint8_t *opt = &buf[4];
438 uint8_t *opt_end = opt + len - 4;
439
440 round_start = odhcp6c_get_milli_time();
441 elapsed = round_start - start;
442 syslog(LOG_NOTICE, "Got a valid reply after "
443 "%ums", (unsigned)elapsed);
444
445 if (retx->handler_reply)
446 len = retx->handler_reply(
447 type, opt, opt_end);
448
449 if (round_end - round_start > 1000)
450 round_end = 1000 + round_start;
451 }
452 }
453
454 // Allow
455 if (retx->handler_finish)
456 len = retx->handler_finish();
457 } while (len < 0 && elapsed / 1000 < timeout);
458
459 return len;
460 }
461
462
463 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
464 const uint8_t transaction[3], enum dhcpv6_msg type)
465 {
466 const struct dhcpv6_header *rep = buf;
467 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
468 transaction, sizeof(rep->tr_id)))
469 return false; // Invalid reply
470
471 if (type == DHCPV6_MSG_SOLICIT) {
472 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
473 rep->msg_type != DHCPV6_MSG_REPLY)
474 return false;
475 } else if (type == DHCPV6_MSG_UNKNOWN) {
476 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
477 return false;
478 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
479 return false;
480 }
481
482 uint8_t *end = ((uint8_t*)buf) + len, *odata;
483 uint16_t otype, olen;
484 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
485
486 size_t client_id_len, server_id_len;
487 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
488 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
489
490 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
491 if (otype == DHCPV6_OPT_CLIENTID) {
492 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
493 &odata[-4], client_id, client_id_len);
494 } else if (otype == DHCPV6_OPT_SERVERID) {
495 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
496 &odata[-4], server_id, server_id_len);
497 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
498 sizeof(struct dhcpv6_auth_reconfigure)) {
499 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
500 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
501 continue;
502
503 md5_state_t md5;
504 uint8_t serverhash[16], secretbytes[16], hash[16];
505 memcpy(serverhash, r->key, sizeof(serverhash));
506 memset(r->key, 0, sizeof(r->key));
507 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
508
509 for (size_t i = 0; i < sizeof(secretbytes); ++i)
510 secretbytes[i] ^= 0x36;
511
512 md5_init(&md5);
513 md5_append(&md5, secretbytes, sizeof(secretbytes));
514 md5_append(&md5, buf, len);
515 md5_finish(&md5, hash);
516
517 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
518 secretbytes[i] ^= 0x36;
519 secretbytes[i] ^= 0x5c;
520 }
521
522 md5_init(&md5);
523 md5_append(&md5, secretbytes, sizeof(secretbytes));
524 md5_append(&md5, hash, 16);
525 md5_finish(&md5, hash);
526
527 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
528 }
529 }
530
531 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
532 return false;
533
534 return clientid_ok && (serverid_ok || server_id_len == 0);
535 }
536
537
538 int dhcpv6_poll_reconfigure(void)
539 {
540 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
541 if (ret != -1)
542 ret = dhcpv6_request(ret);
543
544 return ret;
545 }
546
547
548 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
549 const void *opt, const void *end)
550 {
551 // TODO: should verify the reconfigure message
552 uint16_t otype, olen;
553 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
554 dhcpv6_for_each_option(opt, end, otype, olen, odata)
555 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
556 odata[0] == DHCPV6_MSG_RENEW ||
557 odata[0] == DHCPV6_MSG_INFO_REQ))
558 msg = odata[0];
559
560 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
561 return msg;
562 }
563
564
565 // Collect all advertised servers
566 static int dhcpv6_handle_advert(enum dhcpv6_msg orig,
567 const void *opt, const void *end)
568 {
569 uint16_t olen, otype;
570 uint8_t *odata;
571 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
572
573 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
574 if (orig == DHCPV6_MSG_SOLICIT &&
575 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
576 olen > sizeof(struct dhcpv6_ia_hdr)) {
577 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
578 dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
579 }
580
581 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
582 memcpy(cand.duid, odata, olen);
583 cand.duid_len = olen;
584 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
585 && odata[1] == DHCPV6_NoAddrsAvail) {
586 if (na_mode == IA_MODE_FORCE) {
587 return -1;
588 } else {
589 cand.has_noaddravail = true;
590 cand.preference -= 1000;
591 }
592 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
593 && odata[1] == DHCPV6_NoPrefixAvail) {
594 cand.preference -= 2000;
595 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
596 cand.preference >= 0) {
597 cand.preference = odata[0];
598 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
599 cand.wants_reconfigure = true;
600 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
601 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
602 uint8_t *oend = odata + olen, *d;
603 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
604 if (otype == DHCPV6_OPT_IA_PREFIX)
605 cand.preference += 2000;
606 else if (otype == DHCPV6_OPT_STATUS &&
607 olen >= 2 && d[0] == 0 &&
608 d[1] == DHCPV6_NoPrefixAvail)
609 cand.preference -= 2000;
610 }
611 }
612 }
613
614 if (cand.duid_len > 0) {
615 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
616 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
617 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
618 }
619
620 if (orig == DHCPV6_MSG_SOLICIT) {
621 odhcp6c_clear_state(STATE_IA_NA);
622 odhcp6c_clear_state(STATE_IA_PD);
623 }
624
625 return -1;
626 }
627
628
629 static int dhcpv6_commit_advert(void)
630 {
631 size_t cand_len;
632 struct dhcpv6_server_cand *c = NULL, *cand =
633 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
634
635 bool retry = false;
636 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
637 if (cand[i].has_noaddravail)
638 retry = true; // We want to try again
639
640 if (!c || c->preference < cand[i].preference)
641 c = &cand[i];
642 }
643
644 if (retry && na_mode == IA_MODE_TRY) {
645 // We give it a second try without the IA_NA
646 na_mode = IA_MODE_NONE;
647 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
648 }
649
650 if (c) {
651 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
652 htons(c->duid_len)};
653 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
654 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
655 accept_reconfig = c->wants_reconfigure;
656 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
657 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
658 }
659
660 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
661 free(cand[i].ia_na);
662 free(cand[i].ia_pd);
663 }
664 odhcp6c_clear_state(STATE_SERVER_CAND);
665
666 if (!c)
667 return -1;
668 else if (request_prefix || na_mode != IA_MODE_NONE)
669 return DHCPV6_STATEFUL;
670 else
671 return DHCPV6_STATELESS;
672 }
673
674
675 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
676 const void *opt, const void *end)
677 {
678 dhcpv6_handle_advert(orig, opt, end);
679 if (dhcpv6_commit_advert() < 0) {
680 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
681 return -1;
682 }
683
684 return dhcpv6_handle_reply(orig, opt, end);
685 }
686
687
688 static int dhcpv6_handle_reply(enum dhcpv6_msg orig,
689 const void *opt, const void *end)
690 {
691 uint8_t *odata;
692 uint16_t otype, olen;
693
694 odhcp6c_expire();
695
696 if (orig == DHCPV6_MSG_UNKNOWN) {
697 static time_t last_update = 0;
698 time_t now = odhcp6c_get_milli_time() / 1000;
699
700 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
701 last_update = now;
702
703 t1 -= elapsed;
704 t2 -= elapsed;
705 t3 -= elapsed;
706
707 if (t1 < 0)
708 t1 = 0;
709
710 if (t2 < 0)
711 t2 = 0;
712
713 if (t3 < 0)
714 t3 = 0;
715 } else {
716 t1 = t2 = t3 = UINT32_MAX;
717 }
718
719 if (orig == DHCPV6_MSG_REQUEST) {
720 // Delete NA and PD we have in the state from the Advert
721 odhcp6c_clear_state(STATE_IA_NA);
722 odhcp6c_clear_state(STATE_IA_PD);
723 }
724
725 if (opt) {
726 odhcp6c_clear_state(STATE_DNS);
727 odhcp6c_clear_state(STATE_SEARCH);
728 odhcp6c_clear_state(STATE_SNTP_IP);
729 odhcp6c_clear_state(STATE_SNTP_FQDN);
730 odhcp6c_clear_state(STATE_SIP_IP);
731 odhcp6c_clear_state(STATE_SIP_FQDN);
732 odhcp6c_clear_state(STATE_AFTR_NAME);
733 }
734
735 // Parse and find all matching IAs
736 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
737 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
738 && olen > sizeof(struct dhcpv6_ia_hdr)) {
739 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
740 uint32_t l_t1 = ntohl(ia_hdr->t1);
741 uint32_t l_t2 = ntohl(ia_hdr->t2);
742
743 // Test ID and T1-T2 validity
744 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
745 continue;
746
747 bool error = false;
748 uint16_t stype, slen;
749 uint8_t *sdata;
750 // Test status and bail if error
751 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
752 stype, slen, sdata)
753 if (stype == DHCPV6_OPT_STATUS && slen >= 2 &&
754 (sdata[0] || sdata[1]))
755 error = true;
756
757 if (error)
758 continue;
759
760 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
761
762 if (!l_t1)
763 l_t1 = 300;
764
765 if (!l_t2)
766 l_t2 = 600;
767
768 if (n < t3)
769 t3 = n;
770
771 // Update times
772 if (l_t1 > 0 && t1 > l_t1)
773 t1 = l_t1;
774
775 if (l_t2 > 0 && t2 > l_t2)
776 t2 = l_t2;
777
778 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
779 if (olen % 16 == 0)
780 odhcp6c_add_state(STATE_DNS, odata, olen);
781 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
782 odhcp6c_add_state(STATE_SEARCH, odata, olen);
783 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
784 uint16_t stype, slen;
785 uint8_t *sdata;
786 // Test status and bail if error
787 dhcpv6_for_each_option(odata, odata + olen,
788 stype, slen, sdata) {
789 if (slen == 16 && (stype == NTP_MC_ADDR ||
790 stype == NTP_SRV_ADDR))
791 odhcp6c_add_state(STATE_SNTP_IP,
792 sdata, slen);
793 else if (slen > 0 && stype == NTP_SRV_FQDN)
794 odhcp6c_add_state(STATE_SNTP_FQDN,
795 sdata, slen);
796 }
797 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
798 if (olen == 16)
799 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
800 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
801 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
802 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
803 uint32_t refresh = ntohl(*((uint32_t*)odata));
804 if (refresh < (uint32_t)t1)
805 t1 = refresh;
806 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
807 sizeof(struct dhcpv6_auth_reconfigure)) {
808 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
809 if (r->protocol == 3 && r->algorithm == 1 &&
810 r->reconf_type == 1)
811 memcpy(reconf_key, r->key, sizeof(r->key));
812 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
813 size_t cur_len;
814 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
815 if (cur_len == 0)
816 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
817 } else if (otype != DHCPV6_OPT_CLIENTID &&
818 otype != DHCPV6_OPT_SERVERID) {
819 odhcp6c_add_state(STATE_CUSTOM_OPTS,
820 &odata[-4], olen + 4);
821 }
822 }
823
824 return true;
825 }
826
827
828 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
829 {
830 uint32_t timeout = UINT32_MAX; // Minimum timeout
831 uint16_t otype, olen;
832 uint8_t *odata;
833
834 // Update address IA
835 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
836 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
837 IN6ADDR_ANY_INIT, 0, 0, 0};
838
839 if (otype == DHCPV6_OPT_IA_PREFIX) {
840 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
841 if (olen + 4U < sizeof(*prefix))
842 continue;
843
844 entry.valid = ntohl(prefix->valid);
845 entry.preferred = ntohl(prefix->preferred);
846
847 if (entry.preferred > entry.valid)
848 continue;
849
850 entry.length = prefix->prefix;
851 entry.target = prefix->addr;
852 uint16_t stype, slen;
853 uint8_t *sdata;
854
855 #ifdef EXT_PREFIX_CLASS
856 // Find prefix class, if any
857 dhcpv6_for_each_option(&prefix[1], odata + olen,
858 stype, slen, sdata)
859 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
860 entry.class = sdata[0] << 8 | sdata[1];
861 #endif
862
863 // Parse PD-exclude
864 bool ok = true;
865 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
866 odata + olen, stype, slen, sdata) {
867 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
868 continue;
869
870 uint8_t elen = sdata[0];
871 if (elen > 64)
872 elen = 64;
873
874 if (elen <= 32 || elen <= entry.length) {
875 ok = false;
876 continue;
877 }
878
879
880 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
881 if (slen <= bytes) {
882 ok = false;
883 continue;
884 }
885
886 uint32_t exclude = 0;
887 do {
888 exclude = exclude << 8 | sdata[bytes];
889 } while (--bytes);
890
891 exclude >>= 8 - ((elen - entry.length) % 8);
892 exclude <<= 64 - elen;
893
894 // Abusing router & priority fields for exclusion
895 entry.router = entry.target;
896 entry.router.s6_addr32[1] |= htonl(exclude);
897 entry.priority = elen;
898 }
899
900 if (ok)
901 odhcp6c_update_entry(STATE_IA_PD, &entry);
902
903 entry.priority = 0;
904 memset(&entry.router, 0, sizeof(entry.router));
905 } else if (otype == DHCPV6_OPT_IA_ADDR) {
906 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
907 if (olen + 4U < sizeof(*addr))
908 continue;
909
910 entry.preferred = ntohl(addr->preferred);
911 entry.valid = ntohl(addr->valid);
912
913 if (entry.preferred > entry.valid)
914 continue;
915
916 entry.length = 128;
917 entry.target = addr->addr;
918
919 #ifdef EXT_PREFIX_CLASS
920 uint16_t stype, slen;
921 uint8_t *sdata;
922 // Find prefix class, if any
923 dhcpv6_for_each_option(&addr[1], odata + olen,
924 stype, slen, sdata)
925 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
926 entry.class = sdata[0] << 8 | sdata[1];
927 #endif
928
929 odhcp6c_update_entry(STATE_IA_NA, &entry);
930 }
931 if (entry.valid > 0 && timeout > entry.valid)
932 timeout = entry.valid;
933 }
934
935 return timeout;
936 }
Openwrt DHCPv6 Client