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Don't hang indefinitely if REQUEST is never answered
[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, 1, 30, "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, 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)
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_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
171 {
172 na_mode = na;
173 pd_mode = pd;
174 }
175
176
177 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
178 {
179 // Build FQDN
180 char fqdn_buf[256];
181 gethostname(fqdn_buf, sizeof(fqdn_buf));
182 struct {
183 uint16_t type;
184 uint16_t len;
185 uint8_t flags;
186 uint8_t data[256];
187 } fqdn;
188 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
189 sizeof(fqdn.data), NULL, NULL);
190 fqdn.type = htons(DHCPV6_OPT_FQDN);
191 fqdn.len = htons(fqdn_len - 4);
192 fqdn.flags = 0;
193
194
195 // Build Client ID
196 size_t cl_id_len;
197 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
198
199 // Get Server ID
200 size_t srv_id_len;
201 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
202
203 // Build IA_PDs
204 size_t ia_pd_entries, ia_pd_len = 0;
205 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
206 ia_pd_entries /= sizeof(*e);
207 struct dhcpv6_ia_hdr hdr_ia_pd = {
208 htons(DHCPV6_OPT_IA_PD),
209 htons(sizeof(hdr_ia_pd) - 4),
210 1, 0, 0
211 };
212
213
214 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
215 for (size_t i = 0; i < ia_pd_entries; ++i) {
216 uint8_t ex_len = 0;
217 if (e[i].priority > 0)
218 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
219
220 struct dhcpv6_ia_prefix p = {
221 .type = htons(DHCPV6_OPT_IA_PREFIX),
222 .len = htons(sizeof(p) - 4U + ex_len),
223 .prefix = e[i].length,
224 .addr = e[i].target
225 };
226
227 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
228 ia_pd_len += sizeof(p);
229
230 if (ex_len) {
231 ia_pd[ia_pd_len++] = 0;
232 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
233 ia_pd[ia_pd_len++] = 0;
234 ia_pd[ia_pd_len++] = ex_len - 4;
235 ia_pd[ia_pd_len++] = e[i].priority;
236
237 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
238 excl >>= (64 - e[i].priority);
239 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
240
241 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
242 ia_pd[ia_pd_len + i] = excl & 0xff;
243 ia_pd_len += ex_len - 5;
244 }
245 }
246
247 struct dhcpv6_ia_prefix pref = {
248 .type = htons(DHCPV6_OPT_IA_PREFIX),
249 .len = htons(25), .prefix = request_prefix
250 };
251 if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
252 ia_pd = (uint8_t*)&pref;
253 ia_pd_len = sizeof(pref);
254 }
255 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
256
257 // Build IA_NAs
258 size_t ia_na_entries, ia_na_len = 0;
259 void *ia_na = NULL;
260 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
261 ia_na_entries /= sizeof(*e);
262
263 struct dhcpv6_ia_hdr hdr_ia_na = {
264 htons(DHCPV6_OPT_IA_NA),
265 htons(sizeof(hdr_ia_na) - 4),
266 1, 0, 0
267 };
268
269 struct dhcpv6_ia_addr pa[ia_na_entries];
270 for (size_t i = 0; i < ia_na_entries; ++i) {
271 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
272 pa[i].len = htons(sizeof(pa[i]) - 4U);
273 pa[i].addr = e[i].target;
274 pa[i].preferred = 0;
275 pa[i].valid = 0;
276 }
277
278 ia_na = pa;
279 ia_na_len = sizeof(pa);
280 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
281
282 // Reconfigure Accept
283 struct {
284 uint16_t type;
285 uint16_t length;
286 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
287
288 // Request Information Refresh
289 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
290
291 // Prepare Header
292 size_t oro_len;
293 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
294 struct {
295 uint8_t type;
296 uint8_t trid[3];
297 uint16_t elapsed_type;
298 uint16_t elapsed_len;
299 uint16_t elapsed_value;
300 uint16_t oro_type;
301 uint16_t oro_len;
302 } hdr = {
303 type, {trid[0], trid[1], trid[2]},
304 htons(DHCPV6_OPT_ELAPSED), htons(2),
305 htons((ecs > 0xffff) ? 0xffff : ecs),
306 htons(DHCPV6_OPT_ORO), htons(oro_len),
307 };
308
309 struct iovec iov[] = {
310 {&hdr, sizeof(hdr)},
311 {oro, oro_len},
312 {&oro_refresh, 0},
313 {cl_id, cl_id_len},
314 {srv_id, srv_id_len},
315 {&reconf_accept, sizeof(reconf_accept)},
316 {&fqdn, fqdn_len},
317 {&hdr_ia_na, sizeof(hdr_ia_na)},
318 {ia_na, ia_na_len},
319 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
320 {ia_pd, ia_pd_len},
321 };
322
323 size_t cnt = ARRAY_SIZE(iov);
324 if (type == DHCPV6_MSG_INFO_REQ) {
325 cnt = 5;
326 iov[2].iov_len = sizeof(oro_refresh);
327 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
328 } else if (!request_prefix) {
329 cnt = 9;
330 }
331
332 // Disable IAs if not used
333 if (type != DHCPV6_MSG_SOLICIT) {
334 iov[5].iov_len = 0;
335 if (ia_na_len == 0)
336 iov[7].iov_len = 0;
337 if (ia_pd_len == 0)
338 iov[9].iov_len = 0;
339 }
340
341 if (na_mode == IA_MODE_NONE)
342 iov[7].iov_len = 0;
343
344 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
345 0, ALL_DHCPV6_RELAYS, ifindex};
346 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
347
348 sendmsg(sock, &msg, 0);
349 }
350
351
352 static int64_t dhcpv6_rand_delay(int64_t time)
353 {
354 int random;
355 odhcp6c_random(&random, sizeof(random));
356 return (time * ((int64_t)random % 1000LL)) / 10000LL;
357 }
358
359
360 int dhcpv6_request(enum dhcpv6_msg type)
361 {
362 uint8_t buf[1536];
363 uint64_t timeout = UINT32_MAX;
364 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
365
366 if (retx->delay) {
367 struct timespec ts = {0, 0};
368 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
369 nanosleep(&ts, NULL);
370 }
371
372 if (type == DHCPV6_MSG_REQUEST)
373 timeout = 60;
374 else if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
375 timeout = 3;
376 else if (type == DHCPV6_MSG_UNKNOWN)
377 timeout = t1;
378 else if (type == DHCPV6_MSG_RENEW)
379 timeout = (t2 > t1) ? t2 - t1 : 0;
380 else if (type == DHCPV6_MSG_REBIND)
381 timeout = (t3 > t2) ? t3 - t2 : 0;
382
383 if (timeout == 0)
384 return -1;
385
386 syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, (unsigned)timeout);
387
388 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
389
390 // Generate transaction ID
391 uint8_t trid[3] = {0, 0, 0};
392 if (type != DHCPV6_MSG_UNKNOWN)
393 odhcp6c_random(trid, sizeof(trid));
394 ssize_t len = -1;
395 int64_t rto = 0;
396
397 do {
398 rto = (rto == 0) ? (retx->init_timeo * 1000 +
399 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
400 (2 * rto + dhcpv6_rand_delay(rto));
401
402 if (rto >= retx->max_timeo * 1000)
403 rto = retx->max_timeo * 1000 +
404 dhcpv6_rand_delay(retx->max_timeo * 1000);
405
406 // Calculate end for this round and elapsed time
407 uint64_t round_end = round_start + rto;
408 elapsed = round_start - start;
409
410 // Don't wait too long
411 if (round_end - start > timeout * 1000)
412 round_end = timeout * 1000 + start;
413
414 // Built and send package
415 if (type != DHCPV6_MSG_UNKNOWN)
416 dhcpv6_send(type, trid, elapsed / 10);
417
418 // Receive rounds
419 for (; len < 0 && round_start < round_end;
420 round_start = odhcp6c_get_milli_time()) {
421 // Check for pending signal
422 if (odhcp6c_signal_process())
423 return -1;
424
425 // Set timeout for receiving
426 uint64_t t = round_end - round_start;
427 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
428 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
429 &timeout, sizeof(timeout));
430
431 // Receive cycle
432 len = recv(sock, buf, sizeof(buf), 0);
433
434 if (!dhcpv6_response_is_valid(buf, len, trid, type))
435 len = -1;
436
437 if (len > 0) {
438 uint8_t *opt = &buf[4];
439 uint8_t *opt_end = opt + len - 4;
440
441 round_start = odhcp6c_get_milli_time();
442 elapsed = round_start - start;
443 syslog(LOG_NOTICE, "Got a valid reply after "
444 "%ums", (unsigned)elapsed);
445
446 if (retx->handler_reply)
447 len = retx->handler_reply(
448 type, opt, opt_end);
449
450 if (len > 0 && round_end - round_start > 1000)
451 round_end = 1000 + round_start;
452 }
453 }
454
455 // Allow
456 if (retx->handler_finish)
457 len = retx->handler_finish();
458 } while (len < 0 && elapsed / 1000 < timeout);
459
460 return len;
461 }
462
463
464 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
465 const uint8_t transaction[3], enum dhcpv6_msg type)
466 {
467 const struct dhcpv6_header *rep = buf;
468 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
469 transaction, sizeof(rep->tr_id)))
470 return false; // Invalid reply
471
472 if (type == DHCPV6_MSG_SOLICIT) {
473 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
474 rep->msg_type != DHCPV6_MSG_REPLY)
475 return false;
476 } else if (type == DHCPV6_MSG_UNKNOWN) {
477 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
478 return false;
479 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
480 return false;
481 }
482
483 uint8_t *end = ((uint8_t*)buf) + len, *odata;
484 uint16_t otype, olen;
485 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
486
487 size_t client_id_len, server_id_len;
488 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
489 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
490
491 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
492 if (otype == DHCPV6_OPT_CLIENTID) {
493 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
494 &odata[-4], client_id, client_id_len);
495 } else if (otype == DHCPV6_OPT_SERVERID) {
496 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
497 &odata[-4], server_id, server_id_len);
498 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
499 sizeof(struct dhcpv6_auth_reconfigure)) {
500 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
501 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
502 continue;
503
504 md5_state_t md5;
505 uint8_t serverhash[16], secretbytes[16], hash[16];
506 memcpy(serverhash, r->key, sizeof(serverhash));
507 memset(r->key, 0, sizeof(r->key));
508 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
509
510 for (size_t i = 0; i < sizeof(secretbytes); ++i)
511 secretbytes[i] ^= 0x36;
512
513 md5_init(&md5);
514 md5_append(&md5, secretbytes, sizeof(secretbytes));
515 md5_append(&md5, buf, len);
516 md5_finish(&md5, hash);
517
518 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
519 secretbytes[i] ^= 0x36;
520 secretbytes[i] ^= 0x5c;
521 }
522
523 md5_init(&md5);
524 md5_append(&md5, secretbytes, sizeof(secretbytes));
525 md5_append(&md5, hash, 16);
526 md5_finish(&md5, hash);
527
528 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
529 }
530 }
531
532 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
533 return false;
534
535 return clientid_ok && (serverid_ok || server_id_len == 0);
536 }
537
538
539 int dhcpv6_poll_reconfigure(void)
540 {
541 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
542 if (ret != -1)
543 ret = dhcpv6_request(ret);
544
545 return ret;
546 }
547
548
549 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
550 const void *opt, const void *end)
551 {
552 // TODO: should verify the reconfigure message
553 uint16_t otype, olen;
554 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
555 dhcpv6_for_each_option(opt, end, otype, olen, odata)
556 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
557 odata[0] == DHCPV6_MSG_RENEW ||
558 odata[0] == DHCPV6_MSG_INFO_REQ))
559 msg = odata[0];
560
561 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
562 return msg;
563 }
564
565
566 // Collect all advertised servers
567 static int dhcpv6_handle_advert(enum dhcpv6_msg orig,
568 const void *opt, const void *end)
569 {
570 uint16_t olen, otype;
571 uint8_t *odata;
572 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
573 bool have_na = false, have_pd = false;
574
575 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
576 if (orig == DHCPV6_MSG_SOLICIT &&
577 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
578 olen > sizeof(struct dhcpv6_ia_hdr)) {
579 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
580 dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
581 }
582
583 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
584 memcpy(cand.duid, odata, olen);
585 cand.duid_len = olen;
586 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
587 && odata[1] == DHCPV6_NoPrefixAvail) {
588 cand.preference -= 2000;
589 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
590 cand.preference >= 0) {
591 cand.preference = odata[0];
592 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
593 cand.wants_reconfigure = true;
594 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
595 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
596 uint8_t *oend = odata + olen, *d;
597 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
598 if (otype == DHCPV6_OPT_IA_PREFIX)
599 have_pd = true;
600 } else if (otype == DHCPV6_OPT_IA_NA) {
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_ADDR)
605 have_na = true;
606 }
607 }
608
609 if ((!have_na && na_mode == IA_MODE_FORCE) ||
610 (!have_pd && pd_mode == IA_MODE_FORCE))
611 return -1;
612
613 if (na_mode != IA_MODE_NONE && !have_na) {
614 cand.has_noaddravail = true;
615 cand.preference -= 1000;
616 }
617
618 if (pd_mode != IA_MODE_NONE) {
619 if (have_pd)
620 cand.preference += 2000;
621 else
622 cand.preference -= 2000;
623 }
624
625 if (cand.duid_len > 0) {
626 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
627 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
628 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
629 }
630
631 if (orig == DHCPV6_MSG_SOLICIT) {
632 odhcp6c_clear_state(STATE_IA_NA);
633 odhcp6c_clear_state(STATE_IA_PD);
634 }
635
636 return -1;
637 }
638
639
640 static int dhcpv6_commit_advert(void)
641 {
642 size_t cand_len;
643 struct dhcpv6_server_cand *c = NULL, *cand =
644 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
645
646 bool retry = false;
647 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
648 if (cand[i].has_noaddravail)
649 retry = true; // We want to try again
650
651 if (!c || c->preference < cand[i].preference)
652 c = &cand[i];
653 }
654
655 if (retry && na_mode == IA_MODE_TRY) {
656 // We give it a second try without the IA_NA
657 na_mode = IA_MODE_NONE;
658 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
659 }
660
661 if (c) {
662 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
663 htons(c->duid_len)};
664 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
665 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
666 accept_reconfig = c->wants_reconfigure;
667 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
668 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
669 }
670
671 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
672 free(cand[i].ia_na);
673 free(cand[i].ia_pd);
674 }
675 odhcp6c_clear_state(STATE_SERVER_CAND);
676
677 if (!c)
678 return -1;
679 else if (request_prefix || na_mode != IA_MODE_NONE)
680 return DHCPV6_STATEFUL;
681 else
682 return DHCPV6_STATELESS;
683 }
684
685
686 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
687 const void *opt, const void *end)
688 {
689 dhcpv6_handle_advert(orig, opt, end);
690 if (dhcpv6_commit_advert() < 0) {
691 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
692 return -1;
693 }
694
695 return dhcpv6_handle_reply(orig, opt, end);
696 }
697
698
699 static int dhcpv6_handle_reply(enum dhcpv6_msg orig,
700 const void *opt, const void *end)
701 {
702 uint8_t *odata;
703 uint16_t otype, olen;
704
705 odhcp6c_expire();
706
707 if (orig == DHCPV6_MSG_UNKNOWN) {
708 static time_t last_update = 0;
709 time_t now = odhcp6c_get_milli_time() / 1000;
710
711 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
712 last_update = now;
713
714 t1 -= elapsed;
715 t2 -= elapsed;
716 t3 -= elapsed;
717
718 if (t1 < 0)
719 t1 = 0;
720
721 if (t2 < 0)
722 t2 = 0;
723
724 if (t3 < 0)
725 t3 = 0;
726 } else {
727 t1 = t2 = t3 = UINT32_MAX;
728 }
729
730 if (orig == DHCPV6_MSG_REQUEST) {
731 // Delete NA and PD we have in the state from the Advert
732 odhcp6c_clear_state(STATE_IA_NA);
733 odhcp6c_clear_state(STATE_IA_PD);
734 }
735
736 if (opt) {
737 odhcp6c_clear_state(STATE_DNS);
738 odhcp6c_clear_state(STATE_SEARCH);
739 odhcp6c_clear_state(STATE_SNTP_IP);
740 odhcp6c_clear_state(STATE_SNTP_FQDN);
741 odhcp6c_clear_state(STATE_SIP_IP);
742 odhcp6c_clear_state(STATE_SIP_FQDN);
743 odhcp6c_clear_state(STATE_AFTR_NAME);
744 }
745
746 // Parse and find all matching IAs
747 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
748 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
749 && olen > sizeof(struct dhcpv6_ia_hdr)) {
750 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
751 uint32_t l_t1 = ntohl(ia_hdr->t1);
752 uint32_t l_t2 = ntohl(ia_hdr->t2);
753
754 // Test ID and T1-T2 validity
755 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
756 continue;
757
758 int error = 0;
759 uint16_t stype, slen;
760 uint8_t *sdata;
761 // Test status and bail if error
762 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
763 stype, slen, sdata)
764 if (stype == DHCPV6_OPT_STATUS && slen >= 2)
765 error = ((int)sdata[0]) << 8 | ((int)sdata[1]);
766
767 if (error) {
768 syslog(LOG_WARNING, "Server returned IAID status %i!", error);
769 if (error != 2)
770 raise(SIGUSR2);
771 break;
772 }
773
774 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
775
776 if (!l_t1)
777 l_t1 = 300;
778
779 if (!l_t2)
780 l_t2 = 600;
781
782 if (n < t3)
783 t3 = n;
784
785 // Update times
786 if (l_t1 > 0 && t1 > l_t1)
787 t1 = l_t1;
788
789 if (l_t2 > 0 && t2 > l_t2)
790 t2 = l_t2;
791
792 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
793 if (olen % 16 == 0)
794 odhcp6c_add_state(STATE_DNS, odata, olen);
795 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
796 odhcp6c_add_state(STATE_SEARCH, odata, olen);
797 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
798 uint16_t stype, slen;
799 uint8_t *sdata;
800 // Test status and bail if error
801 dhcpv6_for_each_option(odata, odata + olen,
802 stype, slen, sdata) {
803 if (slen == 16 && (stype == NTP_MC_ADDR ||
804 stype == NTP_SRV_ADDR))
805 odhcp6c_add_state(STATE_SNTP_IP,
806 sdata, slen);
807 else if (slen > 0 && stype == NTP_SRV_FQDN)
808 odhcp6c_add_state(STATE_SNTP_FQDN,
809 sdata, slen);
810 }
811 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
812 if (olen == 16)
813 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
814 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
815 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
816 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
817 uint32_t refresh = ntohl(*((uint32_t*)odata));
818 if (refresh < (uint32_t)t1)
819 t1 = refresh;
820 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
821 sizeof(struct dhcpv6_auth_reconfigure)) {
822 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
823 if (r->protocol == 3 && r->algorithm == 1 &&
824 r->reconf_type == 1)
825 memcpy(reconf_key, r->key, sizeof(r->key));
826 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
827 size_t cur_len;
828 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
829 if (cur_len == 0)
830 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
831 } else if (otype != DHCPV6_OPT_CLIENTID &&
832 otype != DHCPV6_OPT_SERVERID) {
833 odhcp6c_add_state(STATE_CUSTOM_OPTS,
834 &odata[-4], olen + 4);
835 }
836 }
837
838 if (t1 == UINT32_MAX)
839 t1 = 300;
840
841 if (t2 == UINT32_MAX)
842 t2 = 600;
843
844 if (t3 == UINT32_MAX)
845 t3 = 3600;
846
847 return true;
848 }
849
850
851 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
852 {
853 uint32_t timeout = UINT32_MAX; // Minimum timeout
854 uint16_t otype, olen;
855 uint8_t *odata;
856
857 // Update address IA
858 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
859 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
860 IN6ADDR_ANY_INIT, 0, 0, 0};
861
862 if (otype == DHCPV6_OPT_IA_PREFIX) {
863 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
864 if (olen + 4U < sizeof(*prefix))
865 continue;
866
867 entry.valid = ntohl(prefix->valid);
868 entry.preferred = ntohl(prefix->preferred);
869
870 if (entry.preferred > entry.valid)
871 continue;
872
873 entry.length = prefix->prefix;
874 entry.target = prefix->addr;
875 uint16_t stype, slen;
876 uint8_t *sdata;
877
878 #ifdef EXT_PREFIX_CLASS
879 // Find prefix class, if any
880 dhcpv6_for_each_option(&prefix[1], odata + olen,
881 stype, slen, sdata)
882 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
883 entry.class = sdata[0] << 8 | sdata[1];
884 #endif
885
886 // Parse PD-exclude
887 bool ok = true;
888 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
889 odata + olen, stype, slen, sdata) {
890 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
891 continue;
892
893 uint8_t elen = sdata[0];
894 if (elen > 64)
895 elen = 64;
896
897 if (elen <= 32 || elen <= entry.length) {
898 ok = false;
899 continue;
900 }
901
902
903 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
904 if (slen <= bytes) {
905 ok = false;
906 continue;
907 }
908
909 uint32_t exclude = 0;
910 do {
911 exclude = exclude << 8 | sdata[bytes];
912 } while (--bytes);
913
914 exclude >>= 8 - ((elen - entry.length) % 8);
915 exclude <<= 64 - elen;
916
917 // Abusing router & priority fields for exclusion
918 entry.router = entry.target;
919 entry.router.s6_addr32[1] |= htonl(exclude);
920 entry.priority = elen;
921 }
922
923 if (ok)
924 odhcp6c_update_entry(STATE_IA_PD, &entry);
925
926 entry.priority = 0;
927 memset(&entry.router, 0, sizeof(entry.router));
928 } else if (otype == DHCPV6_OPT_IA_ADDR) {
929 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
930 if (olen + 4U < sizeof(*addr))
931 continue;
932
933 entry.preferred = ntohl(addr->preferred);
934 entry.valid = ntohl(addr->valid);
935
936 if (entry.preferred > entry.valid)
937 continue;
938
939 entry.length = 128;
940 entry.target = addr->addr;
941
942 #ifdef EXT_PREFIX_CLASS
943 uint16_t stype, slen;
944 uint8_t *sdata;
945 // Find prefix class, if any
946 dhcpv6_for_each_option(&addr[1], odata + olen,
947 stype, slen, sdata)
948 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
949 entry.class = sdata[0] << 8 | sdata[1];
950 #endif
951
952 odhcp6c_update_entry(STATE_IA_NA, &entry);
953 }
954 if (entry.valid > 0 && timeout > entry.valid)
955 timeout = entry.valid;
956 }
957
958 return timeout;
959 }
Openwrt DHCPv6 Client