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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, 0, "<POLL>",
62 dhcpv6_handle_reconfigure, NULL},
63 [DHCPV6_MSG_SOLICIT] = {true, 1, 3600, 0, "SOLICIT",
64 dhcpv6_handle_advert, dhcpv6_commit_advert},
65 [DHCPV6_MSG_REQUEST] = {true, 1, 30, 10, "REQUEST",
66 dhcpv6_handle_reply, NULL},
67 [DHCPV6_MSG_RENEW] = {false, 10, 600, 0, "RENEW",
68 dhcpv6_handle_reply, NULL},
69 [DHCPV6_MSG_REBIND] = {false, 10, 600, 0, "REBIND",
70 dhcpv6_handle_rebind_reply, NULL},
71 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
72 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
73 [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, 0, "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, pd_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, int sol_timeout)
94 {
95 request_prefix = request_pd;
96 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
97
98 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
99
100 // Detect interface
101 struct ifreq ifr;
102 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
103 if (ioctl(sock, SIOCGIFINDEX, &ifr))
104 return -1;
105 ifindex = ifr.ifr_ifindex;
106
107 // Create client DUID
108 size_t client_id_len;
109 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
110 if (client_id_len == 0) {
111 ioctl(sock, SIOCGIFHWADDR, &ifr);
112 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
113 DHCPV6_DUID_LLADDR, 0, 1};
114 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
115
116 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
117 struct ifreq ifs[100], *ifp, *ifend;
118 struct ifconf ifc;
119 ifc.ifc_req = ifs;
120 ifc.ifc_len = sizeof(ifs);
121
122 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
123 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
124 // If our interface doesn't have an address...
125 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
126 for (ifp = ifc.ifc_req; ifp < ifend &&
127 !memcmp(&duid[8], zero, 6); ifp++) {
128 memcpy(ifr.ifr_name, ifp->ifr_name,
129 sizeof(ifr.ifr_name));
130 ioctl(sock, SIOCGIFHWADDR, &ifr);
131 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
132 ETHER_ADDR_LEN);
133 }
134 }
135
136 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
137 }
138
139 // Create ORO
140 uint16_t oro[] = {
141 htons(DHCPV6_OPT_SIP_SERVER_D),
142 htons(DHCPV6_OPT_SIP_SERVER_A),
143 htons(DHCPV6_OPT_DNS_SERVERS),
144 htons(DHCPV6_OPT_DNS_DOMAIN),
145 htons(DHCPV6_OPT_NTP_SERVER),
146 htons(DHCPV6_OPT_SIP_SERVER_A),
147 htons(DHCPV6_OPT_AFTR_NAME),
148 htons(DHCPV6_OPT_PD_EXCLUDE),
149 #ifdef EXT_PREFIX_CLASS
150 htons(DHCPV6_OPT_PREFIX_CLASS),
151 #endif
152 };
153 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
154
155
156 // Configure IPv6-options
157 int val = 1;
158 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
159 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
160 val = 0;
161 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
162 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
163
164 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
165 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
166 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
167 return -1;
168
169 return 0;
170 }
171
172
173 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
174 {
175 na_mode = na;
176 pd_mode = pd;
177 }
178
179
180 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
181 {
182 // Build FQDN
183 char fqdn_buf[256];
184 gethostname(fqdn_buf, sizeof(fqdn_buf));
185 struct {
186 uint16_t type;
187 uint16_t len;
188 uint8_t flags;
189 uint8_t data[256];
190 } fqdn;
191 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
192 sizeof(fqdn.data), NULL, NULL);
193 fqdn.type = htons(DHCPV6_OPT_FQDN);
194 fqdn.len = htons(fqdn_len - 4);
195 fqdn.flags = 0;
196
197
198 // Build Client ID
199 size_t cl_id_len;
200 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
201
202 // Get Server ID
203 size_t srv_id_len;
204 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
205
206 // Build IA_PDs
207 size_t ia_pd_entries, ia_pd_len = 0;
208 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
209 ia_pd_entries /= sizeof(*e);
210 struct dhcpv6_ia_hdr hdr_ia_pd = {
211 htons(DHCPV6_OPT_IA_PD),
212 htons(sizeof(hdr_ia_pd) - 4),
213 1, 0, 0
214 };
215
216
217 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
218 for (size_t i = 0; i < ia_pd_entries; ++i) {
219 uint8_t ex_len = 0;
220 if (e[i].priority > 0)
221 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
222
223 struct dhcpv6_ia_prefix p = {
224 .type = htons(DHCPV6_OPT_IA_PREFIX),
225 .len = htons(sizeof(p) - 4U + ex_len),
226 .prefix = e[i].length,
227 .addr = e[i].target
228 };
229
230 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
231 ia_pd_len += sizeof(p);
232
233 if (ex_len) {
234 ia_pd[ia_pd_len++] = 0;
235 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
236 ia_pd[ia_pd_len++] = 0;
237 ia_pd[ia_pd_len++] = ex_len - 4;
238 ia_pd[ia_pd_len++] = e[i].priority;
239
240 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
241 excl >>= (64 - e[i].priority);
242 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
243
244 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
245 ia_pd[ia_pd_len + i] = excl & 0xff;
246 ia_pd_len += ex_len - 5;
247 }
248 }
249
250 struct dhcpv6_ia_prefix pref = {
251 .type = htons(DHCPV6_OPT_IA_PREFIX),
252 .len = htons(25), .prefix = request_prefix
253 };
254 if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
255 ia_pd = (uint8_t*)&pref;
256 ia_pd_len = sizeof(pref);
257 }
258 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
259
260 // Build IA_NAs
261 size_t ia_na_entries, ia_na_len = 0;
262 void *ia_na = NULL;
263 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
264 ia_na_entries /= sizeof(*e);
265
266 struct dhcpv6_ia_hdr hdr_ia_na = {
267 htons(DHCPV6_OPT_IA_NA),
268 htons(sizeof(hdr_ia_na) - 4),
269 1, 0, 0
270 };
271
272 struct dhcpv6_ia_addr pa[ia_na_entries];
273 for (size_t i = 0; i < ia_na_entries; ++i) {
274 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
275 pa[i].len = htons(sizeof(pa[i]) - 4U);
276 pa[i].addr = e[i].target;
277 pa[i].preferred = 0;
278 pa[i].valid = 0;
279 }
280
281 ia_na = pa;
282 ia_na_len = sizeof(pa);
283 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
284
285 // Reconfigure Accept
286 struct {
287 uint16_t type;
288 uint16_t length;
289 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
290
291 // Request Information Refresh
292 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
293
294 // Prepare Header
295 size_t oro_len;
296 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
297 struct {
298 uint8_t type;
299 uint8_t trid[3];
300 uint16_t elapsed_type;
301 uint16_t elapsed_len;
302 uint16_t elapsed_value;
303 uint16_t oro_type;
304 uint16_t oro_len;
305 } hdr = {
306 type, {trid[0], trid[1], trid[2]},
307 htons(DHCPV6_OPT_ELAPSED), htons(2),
308 htons((ecs > 0xffff) ? 0xffff : ecs),
309 htons(DHCPV6_OPT_ORO), htons(oro_len),
310 };
311
312 struct iovec iov[] = {
313 {&hdr, sizeof(hdr)},
314 {oro, oro_len},
315 {&oro_refresh, 0},
316 {cl_id, cl_id_len},
317 {srv_id, srv_id_len},
318 {&reconf_accept, sizeof(reconf_accept)},
319 {&fqdn, fqdn_len},
320 {&hdr_ia_na, sizeof(hdr_ia_na)},
321 {ia_na, ia_na_len},
322 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
323 {ia_pd, ia_pd_len},
324 };
325
326 size_t cnt = ARRAY_SIZE(iov);
327 if (type == DHCPV6_MSG_INFO_REQ) {
328 cnt = 5;
329 iov[2].iov_len = sizeof(oro_refresh);
330 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
331 } else if (!request_prefix) {
332 cnt = 9;
333 }
334
335 // Disable IAs if not used
336 if (type != DHCPV6_MSG_SOLICIT) {
337 iov[5].iov_len = 0;
338 if (ia_na_len == 0)
339 iov[7].iov_len = 0;
340 if (ia_pd_len == 0)
341 iov[9].iov_len = 0;
342 }
343
344 if (na_mode == IA_MODE_NONE)
345 iov[7].iov_len = 0;
346
347 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
348 0, ALL_DHCPV6_RELAYS, ifindex};
349 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
350
351 sendmsg(sock, &msg, 0);
352 }
353
354
355 static int64_t dhcpv6_rand_delay(int64_t time)
356 {
357 int random;
358 odhcp6c_random(&random, sizeof(random));
359 return (time * ((int64_t)random % 1000LL)) / 10000LL;
360 }
361
362
363 int dhcpv6_request(enum dhcpv6_msg type)
364 {
365 uint8_t buf[1536], rc = 0;
366 uint64_t timeout = UINT32_MAX;
367 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
368
369 if (retx->delay) {
370 struct timespec ts = {0, 0};
371 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
372 nanosleep(&ts, NULL);
373 }
374
375 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, "Starting %s transaction (timeout %llus, max rc %d)", retx->name, timeout, retx->max_rc);
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 if (rto == 0) {
398 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
399
400 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
401 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
402 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
403
404 rto = (retx->init_timeo * 1000 + delay);
405 }
406 else
407 rto = (2 * rto + dhcpv6_rand_delay(rto));
408
409 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
410 rto = retx->max_timeo * 1000 +
411 dhcpv6_rand_delay(retx->max_timeo * 1000);
412
413 // Calculate end for this round and elapsed time
414 uint64_t round_end = round_start + rto;
415 elapsed = round_start - start;
416
417 // Don't wait too long
418 if (round_end - start > timeout * 1000)
419 round_end = timeout * 1000 + start;
420
421 // Built and send package
422 if (type != DHCPV6_MSG_UNKNOWN) {
423 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)", retx->name, elapsed, rc);
424 dhcpv6_send(type, trid, elapsed / 10);
425 rc++;
426 }
427
428 // Receive rounds
429 for (; len < 0 && round_start < round_end;
430 round_start = odhcp6c_get_milli_time()) {
431 // Check for pending signal
432 if (odhcp6c_signal_process())
433 return -1;
434
435 // Set timeout for receiving
436 uint64_t t = round_end - round_start;
437 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
438 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
439 &timeout, sizeof(timeout));
440
441 // Receive cycle
442 len = recv(sock, buf, sizeof(buf), 0);
443
444 if (!dhcpv6_response_is_valid(buf, len, trid, type))
445 len = -1;
446
447 if (len > 0) {
448 uint8_t *opt = &buf[4];
449 uint8_t *opt_end = opt + len - 4;
450
451 round_start = odhcp6c_get_milli_time();
452 elapsed = round_start - start;
453 syslog(LOG_NOTICE, "Got a valid reply after "
454 "%llums", elapsed);
455
456 if (retx->handler_reply)
457 len = retx->handler_reply(
458 type, rc, opt, opt_end);
459
460 if (len > 0 && round_end - round_start > 1000)
461 round_end = 1000 + round_start;
462 }
463 }
464
465 // Allow
466 if (retx->handler_finish)
467 len = retx->handler_finish();
468 } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
469
470 return len;
471 }
472
473
474 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
475 const uint8_t transaction[3], enum dhcpv6_msg type)
476 {
477 const struct dhcpv6_header *rep = buf;
478 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
479 transaction, sizeof(rep->tr_id)))
480 return false; // Invalid reply
481
482 if (type == DHCPV6_MSG_SOLICIT) {
483 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
484 rep->msg_type != DHCPV6_MSG_REPLY)
485 return false;
486 } else if (type == DHCPV6_MSG_UNKNOWN) {
487 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
488 return false;
489 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
490 return false;
491 }
492
493 uint8_t *end = ((uint8_t*)buf) + len, *odata;
494 uint16_t otype, olen;
495 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
496
497 size_t client_id_len, server_id_len;
498 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
499 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
500
501 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
502 if (otype == DHCPV6_OPT_CLIENTID) {
503 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
504 &odata[-4], client_id, client_id_len);
505 } else if (otype == DHCPV6_OPT_SERVERID) {
506 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
507 &odata[-4], server_id, server_id_len);
508 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
509 sizeof(struct dhcpv6_auth_reconfigure)) {
510 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
511 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
512 continue;
513
514 md5_state_t md5;
515 uint8_t serverhash[16], secretbytes[16], hash[16];
516 memcpy(serverhash, r->key, sizeof(serverhash));
517 memset(r->key, 0, sizeof(r->key));
518 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
519
520 for (size_t i = 0; i < sizeof(secretbytes); ++i)
521 secretbytes[i] ^= 0x36;
522
523 md5_init(&md5);
524 md5_append(&md5, secretbytes, sizeof(secretbytes));
525 md5_append(&md5, buf, len);
526 md5_finish(&md5, hash);
527
528 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
529 secretbytes[i] ^= 0x36;
530 secretbytes[i] ^= 0x5c;
531 }
532
533 md5_init(&md5);
534 md5_append(&md5, secretbytes, sizeof(secretbytes));
535 md5_append(&md5, hash, 16);
536 md5_finish(&md5, hash);
537
538 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
539 }
540 }
541
542 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
543 return false;
544
545 return clientid_ok && (serverid_ok || server_id_len == 0);
546 }
547
548
549 int dhcpv6_poll_reconfigure(void)
550 {
551 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
552 if (ret != -1)
553 ret = dhcpv6_request(ret);
554
555 return ret;
556 }
557
558
559 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
560 const void *opt, const void *end)
561 {
562 // TODO: should verify the reconfigure message
563 uint16_t otype, olen;
564 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
565 dhcpv6_for_each_option(opt, end, otype, olen, odata)
566 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
567 odata[0] == DHCPV6_MSG_RENEW ||
568 odata[0] == DHCPV6_MSG_INFO_REQ))
569 msg = odata[0];
570
571 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
572 return msg;
573 }
574
575
576 // Collect all advertised servers
577 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, _unused const int rc,
578 const void *opt, const void *end)
579 {
580 uint16_t olen, otype;
581 uint8_t *odata;
582 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
583 bool have_na = false;
584 int have_pd = 0;
585
586 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
587 if (orig == DHCPV6_MSG_SOLICIT &&
588 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
589 olen > sizeof(struct dhcpv6_ia_hdr)) {
590 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
591 dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
592 }
593
594 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
595 memcpy(cand.duid, odata, olen);
596 cand.duid_len = olen;
597 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
598 && odata[1] == DHCPV6_NoPrefixAvail) {
599 cand.preference -= 2000;
600 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
601 cand.preference >= 0) {
602 cand.preference = odata[0];
603 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
604 cand.wants_reconfigure = true;
605 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
606 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
607 uint8_t *oend = odata + olen, *d;
608 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
609 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
610 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
611 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
612 have_pd = p->prefix;
613 }
614 }
615 } else if (otype == DHCPV6_OPT_IA_NA) {
616 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
617 uint8_t *oend = odata + olen, *d;
618 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
619 if (otype == DHCPV6_OPT_IA_ADDR)
620 have_na = true;
621 }
622 }
623
624 if ((!have_na && na_mode == IA_MODE_FORCE) ||
625 (!have_pd && pd_mode == IA_MODE_FORCE))
626 return -1;
627
628 if (na_mode != IA_MODE_NONE && !have_na) {
629 cand.has_noaddravail = true;
630 cand.preference -= 1000;
631 }
632
633 if (pd_mode != IA_MODE_NONE) {
634 if (have_pd)
635 cand.preference += 2000 + (128 - have_pd);
636 else
637 cand.preference -= 2000;
638 }
639
640 if (cand.duid_len > 0) {
641 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
642 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
643 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
644 }
645
646 if (orig == DHCPV6_MSG_SOLICIT) {
647 odhcp6c_clear_state(STATE_IA_NA);
648 odhcp6c_clear_state(STATE_IA_PD);
649 }
650
651 return -1;
652 }
653
654
655 static int dhcpv6_commit_advert(void)
656 {
657 size_t cand_len;
658 struct dhcpv6_server_cand *c = NULL, *cand =
659 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
660
661 bool retry = false;
662 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
663 if (cand[i].has_noaddravail)
664 retry = true; // We want to try again
665
666 if (!c || c->preference < cand[i].preference)
667 c = &cand[i];
668 }
669
670 if (retry && na_mode == IA_MODE_TRY) {
671 // We give it a second try without the IA_NA
672 na_mode = IA_MODE_NONE;
673 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
674 }
675
676 if (c) {
677 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
678 htons(c->duid_len)};
679 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
680 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
681 accept_reconfig = c->wants_reconfigure;
682 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
683 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
684 }
685
686 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
687 free(cand[i].ia_na);
688 free(cand[i].ia_pd);
689 }
690 odhcp6c_clear_state(STATE_SERVER_CAND);
691
692 if (!c)
693 return -1;
694 else if (request_prefix || na_mode != IA_MODE_NONE)
695 return DHCPV6_STATEFUL;
696 else
697 return DHCPV6_STATELESS;
698 }
699
700
701 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
702 const void *opt, const void *end)
703 {
704 dhcpv6_handle_advert(orig, rc, opt, end);
705 if (dhcpv6_commit_advert() < 0) {
706 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
707 return -1;
708 }
709
710 return dhcpv6_handle_reply(orig, rc, opt, end);
711 }
712
713
714 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
715 const void *opt, const void *end)
716 {
717 uint8_t *odata;
718 uint16_t otype, olen;
719
720 odhcp6c_expire();
721
722 if (orig == DHCPV6_MSG_UNKNOWN) {
723 static time_t last_update = 0;
724 time_t now = odhcp6c_get_milli_time() / 1000;
725
726 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
727 last_update = now;
728
729 t1 -= elapsed;
730 t2 -= elapsed;
731 t3 -= elapsed;
732
733 if (t1 < 0)
734 t1 = 0;
735
736 if (t2 < 0)
737 t2 = 0;
738
739 if (t3 < 0)
740 t3 = 0;
741 } else {
742 t1 = t2 = t3 = UINT32_MAX;
743 }
744
745 if (orig == DHCPV6_MSG_REQUEST) {
746 // Delete NA and PD we have in the state from the Advert
747 odhcp6c_clear_state(STATE_IA_NA);
748 odhcp6c_clear_state(STATE_IA_PD);
749 }
750
751 if (opt) {
752 odhcp6c_clear_state(STATE_DNS);
753 odhcp6c_clear_state(STATE_SEARCH);
754 odhcp6c_clear_state(STATE_SNTP_IP);
755 odhcp6c_clear_state(STATE_SNTP_FQDN);
756 odhcp6c_clear_state(STATE_SIP_IP);
757 odhcp6c_clear_state(STATE_SIP_FQDN);
758 odhcp6c_clear_state(STATE_AFTR_NAME);
759 }
760
761 // Parse and find all matching IAs
762 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
763 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
764 && olen > sizeof(struct dhcpv6_ia_hdr)) {
765 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
766 uint32_t l_t1 = ntohl(ia_hdr->t1);
767 uint32_t l_t2 = ntohl(ia_hdr->t2);
768
769 // Test ID and T1-T2 validity
770 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
771 continue;
772
773 int error = 0;
774 uint16_t stype, slen;
775 uint8_t *sdata;
776 // Test status and bail if error
777 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
778 stype, slen, sdata)
779 if (stype == DHCPV6_OPT_STATUS && slen >= 2)
780 error = ((int)sdata[0]) << 8 | ((int)sdata[1]);
781
782 if (error) {
783 syslog(LOG_WARNING, "Server returned IAID status %i!", error);
784 if (error != 2)
785 raise(SIGUSR2);
786 break;
787 }
788
789 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
790
791 if (!l_t1)
792 l_t1 = 300;
793
794 if (!l_t2)
795 l_t2 = 600;
796
797 if (n < t3)
798 t3 = n;
799
800 // Update times
801 if (l_t1 > 0 && t1 > l_t1)
802 t1 = l_t1;
803
804 if (l_t2 > 0 && t2 > l_t2)
805 t2 = l_t2;
806
807 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
808 if (olen % 16 == 0)
809 odhcp6c_add_state(STATE_DNS, odata, olen);
810 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
811 odhcp6c_add_state(STATE_SEARCH, odata, olen);
812 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
813 uint16_t stype, slen;
814 uint8_t *sdata;
815 // Test status and bail if error
816 dhcpv6_for_each_option(odata, odata + olen,
817 stype, slen, sdata) {
818 if (slen == 16 && (stype == NTP_MC_ADDR ||
819 stype == NTP_SRV_ADDR))
820 odhcp6c_add_state(STATE_SNTP_IP,
821 sdata, slen);
822 else if (slen > 0 && stype == NTP_SRV_FQDN)
823 odhcp6c_add_state(STATE_SNTP_FQDN,
824 sdata, slen);
825 }
826 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
827 if (olen == 16)
828 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
829 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
830 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
831 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
832 uint32_t refresh = ntohl(*((uint32_t*)odata));
833 if (refresh < (uint32_t)t1)
834 t1 = refresh;
835 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
836 sizeof(struct dhcpv6_auth_reconfigure)) {
837 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
838 if (r->protocol == 3 && r->algorithm == 1 &&
839 r->reconf_type == 1)
840 memcpy(reconf_key, r->key, sizeof(r->key));
841 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
842 size_t cur_len;
843 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
844 if (cur_len == 0)
845 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
846 } else if (otype != DHCPV6_OPT_CLIENTID &&
847 otype != DHCPV6_OPT_SERVERID) {
848 odhcp6c_add_state(STATE_CUSTOM_OPTS,
849 &odata[-4], olen + 4);
850 }
851 }
852
853 if (t1 == UINT32_MAX)
854 t1 = 300;
855
856 if (t2 == UINT32_MAX)
857 t2 = 600;
858
859 if (t3 == UINT32_MAX)
860 t3 = 3600;
861
862 return true;
863 }
864
865
866 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
867 {
868 uint32_t timeout = UINT32_MAX; // Minimum timeout
869 uint16_t otype, olen;
870 uint8_t *odata;
871
872 // Update address IA
873 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
874 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
875 IN6ADDR_ANY_INIT, 0, 0, 0};
876
877 if (otype == DHCPV6_OPT_IA_PREFIX) {
878 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
879 if (olen + 4U < sizeof(*prefix))
880 continue;
881
882 entry.valid = ntohl(prefix->valid);
883 entry.preferred = ntohl(prefix->preferred);
884
885 if (entry.preferred > entry.valid)
886 continue;
887
888 entry.length = prefix->prefix;
889 entry.target = prefix->addr;
890 uint16_t stype, slen;
891 uint8_t *sdata;
892
893 #ifdef EXT_PREFIX_CLASS
894 // Find prefix class, if any
895 dhcpv6_for_each_option(&prefix[1], odata + olen,
896 stype, slen, sdata)
897 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
898 entry.class = sdata[0] << 8 | sdata[1];
899 #endif
900
901 // Parse PD-exclude
902 bool ok = true;
903 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
904 odata + olen, stype, slen, sdata) {
905 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
906 continue;
907
908 uint8_t elen = sdata[0];
909 if (elen > 64)
910 elen = 64;
911
912 if (elen <= 32 || elen <= entry.length) {
913 ok = false;
914 continue;
915 }
916
917
918 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
919 if (slen <= bytes) {
920 ok = false;
921 continue;
922 }
923
924 uint32_t exclude = 0;
925 do {
926 exclude = exclude << 8 | sdata[bytes];
927 } while (--bytes);
928
929 exclude >>= 8 - ((elen - entry.length) % 8);
930 exclude <<= 64 - elen;
931
932 // Abusing router & priority fields for exclusion
933 entry.router = entry.target;
934 entry.router.s6_addr32[1] |= htonl(exclude);
935 entry.priority = elen;
936 }
937
938 if (ok)
939 odhcp6c_update_entry(STATE_IA_PD, &entry);
940
941 entry.priority = 0;
942 memset(&entry.router, 0, sizeof(entry.router));
943 } else if (otype == DHCPV6_OPT_IA_ADDR) {
944 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
945 if (olen + 4U < sizeof(*addr))
946 continue;
947
948 entry.preferred = ntohl(addr->preferred);
949 entry.valid = ntohl(addr->valid);
950
951 if (entry.preferred > entry.valid)
952 continue;
953
954 entry.length = 128;
955 entry.target = addr->addr;
956
957 #ifdef EXT_PREFIX_CLASS
958 uint16_t stype, slen;
959 uint8_t *sdata;
960 // Find prefix class, if any
961 dhcpv6_for_each_option(&addr[1], odata + olen,
962 stype, slen, sdata)
963 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
964 entry.class = sdata[0] << 8 | sdata[1];
965 #endif
966
967 odhcp6c_update_entry(STATE_IA_NA, &entry);
968 }
969 if (entry.valid > 0 && timeout > entry.valid)
970 timeout = entry.valid;
971 }
972
973 return timeout;
974 }
Openwrt DHCPv6 Client