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Make SOL_MAX_RT configurable and default to 120
[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, 120, "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, 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 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
161
162 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
163 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
164 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
165 return -1;
166
167 return 0;
168 }
169
170
171 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
172 {
173 na_mode = na;
174 pd_mode = pd;
175 }
176
177
178 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
179 {
180 // Build FQDN
181 char fqdn_buf[256];
182 gethostname(fqdn_buf, sizeof(fqdn_buf));
183 struct {
184 uint16_t type;
185 uint16_t len;
186 uint8_t flags;
187 uint8_t data[256];
188 } fqdn;
189 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
190 sizeof(fqdn.data), NULL, NULL);
191 fqdn.type = htons(DHCPV6_OPT_FQDN);
192 fqdn.len = htons(fqdn_len - 4);
193 fqdn.flags = 0;
194
195
196 // Build Client ID
197 size_t cl_id_len;
198 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
199
200 // Get Server ID
201 size_t srv_id_len;
202 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
203
204 // Build IA_PDs
205 size_t ia_pd_entries, ia_pd_len = 0;
206 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
207 ia_pd_entries /= sizeof(*e);
208 struct dhcpv6_ia_hdr hdr_ia_pd = {
209 htons(DHCPV6_OPT_IA_PD),
210 htons(sizeof(hdr_ia_pd) - 4),
211 1, 0, 0
212 };
213
214
215 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
216 for (size_t i = 0; i < ia_pd_entries; ++i) {
217 uint8_t ex_len = 0;
218 if (e[i].priority > 0)
219 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
220
221 struct dhcpv6_ia_prefix p = {
222 .type = htons(DHCPV6_OPT_IA_PREFIX),
223 .len = htons(sizeof(p) - 4U + ex_len),
224 .prefix = e[i].length,
225 .addr = e[i].target
226 };
227
228 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
229 ia_pd_len += sizeof(p);
230
231 if (ex_len) {
232 ia_pd[ia_pd_len++] = 0;
233 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
234 ia_pd[ia_pd_len++] = 0;
235 ia_pd[ia_pd_len++] = ex_len - 4;
236 ia_pd[ia_pd_len++] = e[i].priority;
237
238 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
239 excl >>= (64 - e[i].priority);
240 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
241
242 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
243 ia_pd[ia_pd_len + i] = excl & 0xff;
244 ia_pd_len += ex_len - 5;
245 }
246 }
247
248 struct dhcpv6_ia_prefix pref = {
249 .type = htons(DHCPV6_OPT_IA_PREFIX),
250 .len = htons(25), .prefix = request_prefix
251 };
252 if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
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_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_REQUEST)
374 timeout = 60;
375 else if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
376 timeout = 3;
377 else if (type == DHCPV6_MSG_UNKNOWN)
378 timeout = t1;
379 else if (type == DHCPV6_MSG_RENEW)
380 timeout = (t2 > t1) ? t2 - t1 : 0;
381 else if (type == DHCPV6_MSG_REBIND)
382 timeout = (t3 > t2) ? t3 - t2 : 0;
383
384 if (timeout == 0)
385 return -1;
386
387 syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, (unsigned)timeout);
388
389 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
390
391 // Generate transaction ID
392 uint8_t trid[3] = {0, 0, 0};
393 if (type != DHCPV6_MSG_UNKNOWN)
394 odhcp6c_random(trid, sizeof(trid));
395 ssize_t len = -1;
396 int64_t rto = 0;
397
398 do {
399 rto = (rto == 0) ? (retx->init_timeo * 1000 +
400 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
401 (2 * rto + dhcpv6_rand_delay(rto));
402
403 if (rto >= retx->max_timeo * 1000)
404 rto = retx->max_timeo * 1000 +
405 dhcpv6_rand_delay(retx->max_timeo * 1000);
406
407 // Calculate end for this round and elapsed time
408 uint64_t round_end = round_start + rto;
409 elapsed = round_start - start;
410
411 // Don't wait too long
412 if (round_end - start > timeout * 1000)
413 round_end = timeout * 1000 + start;
414
415 // Built and send package
416 if (type != DHCPV6_MSG_UNKNOWN)
417 dhcpv6_send(type, trid, elapsed / 10);
418
419 // Receive rounds
420 for (; len < 0 && round_start < round_end;
421 round_start = odhcp6c_get_milli_time()) {
422 // Check for pending signal
423 if (odhcp6c_signal_process())
424 return -1;
425
426 // Set timeout for receiving
427 uint64_t t = round_end - round_start;
428 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
429 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
430 &timeout, sizeof(timeout));
431
432 // Receive cycle
433 len = recv(sock, buf, sizeof(buf), 0);
434
435 if (!dhcpv6_response_is_valid(buf, len, trid, type))
436 len = -1;
437
438 if (len > 0) {
439 uint8_t *opt = &buf[4];
440 uint8_t *opt_end = opt + len - 4;
441
442 round_start = odhcp6c_get_milli_time();
443 elapsed = round_start - start;
444 syslog(LOG_NOTICE, "Got a valid reply after "
445 "%ums", (unsigned)elapsed);
446
447 if (retx->handler_reply)
448 len = retx->handler_reply(
449 type, opt, opt_end);
450
451 if (len > 0 && round_end - round_start > 1000)
452 round_end = 1000 + round_start;
453 }
454 }
455
456 // Allow
457 if (retx->handler_finish)
458 len = retx->handler_finish();
459 } while (len < 0 && elapsed / 1000 < timeout);
460
461 return len;
462 }
463
464
465 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
466 const uint8_t transaction[3], enum dhcpv6_msg type)
467 {
468 const struct dhcpv6_header *rep = buf;
469 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
470 transaction, sizeof(rep->tr_id)))
471 return false; // Invalid reply
472
473 if (type == DHCPV6_MSG_SOLICIT) {
474 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
475 rep->msg_type != DHCPV6_MSG_REPLY)
476 return false;
477 } else if (type == DHCPV6_MSG_UNKNOWN) {
478 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
479 return false;
480 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
481 return false;
482 }
483
484 uint8_t *end = ((uint8_t*)buf) + len, *odata;
485 uint16_t otype, olen;
486 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
487
488 size_t client_id_len, server_id_len;
489 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
490 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
491
492 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
493 if (otype == DHCPV6_OPT_CLIENTID) {
494 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
495 &odata[-4], client_id, client_id_len);
496 } else if (otype == DHCPV6_OPT_SERVERID) {
497 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
498 &odata[-4], server_id, server_id_len);
499 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
500 sizeof(struct dhcpv6_auth_reconfigure)) {
501 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
502 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
503 continue;
504
505 md5_state_t md5;
506 uint8_t serverhash[16], secretbytes[16], hash[16];
507 memcpy(serverhash, r->key, sizeof(serverhash));
508 memset(r->key, 0, sizeof(r->key));
509 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
510
511 for (size_t i = 0; i < sizeof(secretbytes); ++i)
512 secretbytes[i] ^= 0x36;
513
514 md5_init(&md5);
515 md5_append(&md5, secretbytes, sizeof(secretbytes));
516 md5_append(&md5, buf, len);
517 md5_finish(&md5, hash);
518
519 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
520 secretbytes[i] ^= 0x36;
521 secretbytes[i] ^= 0x5c;
522 }
523
524 md5_init(&md5);
525 md5_append(&md5, secretbytes, sizeof(secretbytes));
526 md5_append(&md5, hash, 16);
527 md5_finish(&md5, hash);
528
529 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
530 }
531 }
532
533 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
534 return false;
535
536 return clientid_ok && (serverid_ok || server_id_len == 0);
537 }
538
539
540 int dhcpv6_poll_reconfigure(void)
541 {
542 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
543 if (ret != -1)
544 ret = dhcpv6_request(ret);
545
546 return ret;
547 }
548
549
550 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
551 const void *opt, const void *end)
552 {
553 // TODO: should verify the reconfigure message
554 uint16_t otype, olen;
555 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
556 dhcpv6_for_each_option(opt, end, otype, olen, odata)
557 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
558 odata[0] == DHCPV6_MSG_RENEW ||
559 odata[0] == DHCPV6_MSG_INFO_REQ))
560 msg = odata[0];
561
562 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
563 return msg;
564 }
565
566
567 // Collect all advertised servers
568 static int dhcpv6_handle_advert(enum dhcpv6_msg orig,
569 const void *opt, const void *end)
570 {
571 uint16_t olen, otype;
572 uint8_t *odata;
573 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
574 bool have_na = false;
575 int have_pd = 0;
576
577 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
578 if (orig == DHCPV6_MSG_SOLICIT &&
579 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
580 olen > sizeof(struct dhcpv6_ia_hdr)) {
581 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
582 dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
583 }
584
585 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
586 memcpy(cand.duid, odata, olen);
587 cand.duid_len = olen;
588 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
589 && odata[1] == DHCPV6_NoPrefixAvail) {
590 cand.preference -= 2000;
591 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
592 cand.preference >= 0) {
593 cand.preference = odata[0];
594 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
595 cand.wants_reconfigure = true;
596 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
597 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
598 uint8_t *oend = odata + olen, *d;
599 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
600 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
601 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
602 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
603 have_pd = p->prefix;
604 }
605 }
606 } else if (otype == DHCPV6_OPT_IA_NA) {
607 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
608 uint8_t *oend = odata + olen, *d;
609 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
610 if (otype == DHCPV6_OPT_IA_ADDR)
611 have_na = true;
612 }
613 }
614
615 if ((!have_na && na_mode == IA_MODE_FORCE) ||
616 (!have_pd && pd_mode == IA_MODE_FORCE))
617 return -1;
618
619 if (na_mode != IA_MODE_NONE && !have_na) {
620 cand.has_noaddravail = true;
621 cand.preference -= 1000;
622 }
623
624 if (pd_mode != IA_MODE_NONE) {
625 if (have_pd)
626 cand.preference += 2000 + (128 - have_pd);
627 else
628 cand.preference -= 2000;
629 }
630
631 if (cand.duid_len > 0) {
632 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
633 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
634 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
635 }
636
637 if (orig == DHCPV6_MSG_SOLICIT) {
638 odhcp6c_clear_state(STATE_IA_NA);
639 odhcp6c_clear_state(STATE_IA_PD);
640 }
641
642 return -1;
643 }
644
645
646 static int dhcpv6_commit_advert(void)
647 {
648 size_t cand_len;
649 struct dhcpv6_server_cand *c = NULL, *cand =
650 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
651
652 bool retry = false;
653 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
654 if (cand[i].has_noaddravail)
655 retry = true; // We want to try again
656
657 if (!c || c->preference < cand[i].preference)
658 c = &cand[i];
659 }
660
661 if (retry && na_mode == IA_MODE_TRY) {
662 // We give it a second try without the IA_NA
663 na_mode = IA_MODE_NONE;
664 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
665 }
666
667 if (c) {
668 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
669 htons(c->duid_len)};
670 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
671 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
672 accept_reconfig = c->wants_reconfigure;
673 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
674 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
675 }
676
677 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
678 free(cand[i].ia_na);
679 free(cand[i].ia_pd);
680 }
681 odhcp6c_clear_state(STATE_SERVER_CAND);
682
683 if (!c)
684 return -1;
685 else if (request_prefix || na_mode != IA_MODE_NONE)
686 return DHCPV6_STATEFUL;
687 else
688 return DHCPV6_STATELESS;
689 }
690
691
692 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
693 const void *opt, const void *end)
694 {
695 dhcpv6_handle_advert(orig, opt, end);
696 if (dhcpv6_commit_advert() < 0) {
697 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL);
698 return -1;
699 }
700
701 return dhcpv6_handle_reply(orig, opt, end);
702 }
703
704
705 static int dhcpv6_handle_reply(enum dhcpv6_msg orig,
706 const void *opt, const void *end)
707 {
708 uint8_t *odata;
709 uint16_t otype, olen;
710
711 odhcp6c_expire();
712
713 if (orig == DHCPV6_MSG_UNKNOWN) {
714 static time_t last_update = 0;
715 time_t now = odhcp6c_get_milli_time() / 1000;
716
717 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
718 last_update = now;
719
720 t1 -= elapsed;
721 t2 -= elapsed;
722 t3 -= elapsed;
723
724 if (t1 < 0)
725 t1 = 0;
726
727 if (t2 < 0)
728 t2 = 0;
729
730 if (t3 < 0)
731 t3 = 0;
732 } else {
733 t1 = t2 = t3 = UINT32_MAX;
734 }
735
736 if (orig == DHCPV6_MSG_REQUEST) {
737 // Delete NA and PD we have in the state from the Advert
738 odhcp6c_clear_state(STATE_IA_NA);
739 odhcp6c_clear_state(STATE_IA_PD);
740 }
741
742 if (opt) {
743 odhcp6c_clear_state(STATE_DNS);
744 odhcp6c_clear_state(STATE_SEARCH);
745 odhcp6c_clear_state(STATE_SNTP_IP);
746 odhcp6c_clear_state(STATE_SNTP_FQDN);
747 odhcp6c_clear_state(STATE_SIP_IP);
748 odhcp6c_clear_state(STATE_SIP_FQDN);
749 odhcp6c_clear_state(STATE_AFTR_NAME);
750 }
751
752 // Parse and find all matching IAs
753 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
754 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
755 && olen > sizeof(struct dhcpv6_ia_hdr)) {
756 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
757 uint32_t l_t1 = ntohl(ia_hdr->t1);
758 uint32_t l_t2 = ntohl(ia_hdr->t2);
759
760 // Test ID and T1-T2 validity
761 if (ia_hdr->iaid != 1 || l_t2 < l_t1)
762 continue;
763
764 int error = 0;
765 uint16_t stype, slen;
766 uint8_t *sdata;
767 // Test status and bail if error
768 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
769 stype, slen, sdata)
770 if (stype == DHCPV6_OPT_STATUS && slen >= 2)
771 error = ((int)sdata[0]) << 8 | ((int)sdata[1]);
772
773 if (error) {
774 syslog(LOG_WARNING, "Server returned IAID status %i!", error);
775 if (error != 2)
776 raise(SIGUSR2);
777 break;
778 }
779
780 uint32_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
781
782 if (!l_t1)
783 l_t1 = 300;
784
785 if (!l_t2)
786 l_t2 = 600;
787
788 if (n < t3)
789 t3 = n;
790
791 // Update times
792 if (l_t1 > 0 && t1 > l_t1)
793 t1 = l_t1;
794
795 if (l_t2 > 0 && t2 > l_t2)
796 t2 = l_t2;
797
798 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
799 if (olen % 16 == 0)
800 odhcp6c_add_state(STATE_DNS, odata, olen);
801 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
802 odhcp6c_add_state(STATE_SEARCH, odata, olen);
803 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
804 uint16_t stype, slen;
805 uint8_t *sdata;
806 // Test status and bail if error
807 dhcpv6_for_each_option(odata, odata + olen,
808 stype, slen, sdata) {
809 if (slen == 16 && (stype == NTP_MC_ADDR ||
810 stype == NTP_SRV_ADDR))
811 odhcp6c_add_state(STATE_SNTP_IP,
812 sdata, slen);
813 else if (slen > 0 && stype == NTP_SRV_FQDN)
814 odhcp6c_add_state(STATE_SNTP_FQDN,
815 sdata, slen);
816 }
817 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
818 if (olen == 16)
819 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
820 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
821 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
822 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
823 uint32_t refresh = ntohl(*((uint32_t*)odata));
824 if (refresh < (uint32_t)t1)
825 t1 = refresh;
826 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
827 sizeof(struct dhcpv6_auth_reconfigure)) {
828 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
829 if (r->protocol == 3 && r->algorithm == 1 &&
830 r->reconf_type == 1)
831 memcpy(reconf_key, r->key, sizeof(r->key));
832 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
833 size_t cur_len;
834 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
835 if (cur_len == 0)
836 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
837 } else if (otype != DHCPV6_OPT_CLIENTID &&
838 otype != DHCPV6_OPT_SERVERID) {
839 odhcp6c_add_state(STATE_CUSTOM_OPTS,
840 &odata[-4], olen + 4);
841 }
842 }
843
844 if (t1 == UINT32_MAX)
845 t1 = 300;
846
847 if (t2 == UINT32_MAX)
848 t2 = 600;
849
850 if (t3 == UINT32_MAX)
851 t3 = 3600;
852
853 return true;
854 }
855
856
857 static uint32_t dhcpv6_parse_ia(void *opt, void *end)
858 {
859 uint32_t timeout = UINT32_MAX; // Minimum timeout
860 uint16_t otype, olen;
861 uint8_t *odata;
862
863 // Update address IA
864 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
865 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
866 IN6ADDR_ANY_INIT, 0, 0, 0};
867
868 if (otype == DHCPV6_OPT_IA_PREFIX) {
869 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
870 if (olen + 4U < sizeof(*prefix))
871 continue;
872
873 entry.valid = ntohl(prefix->valid);
874 entry.preferred = ntohl(prefix->preferred);
875
876 if (entry.preferred > entry.valid)
877 continue;
878
879 entry.length = prefix->prefix;
880 entry.target = prefix->addr;
881 uint16_t stype, slen;
882 uint8_t *sdata;
883
884 #ifdef EXT_PREFIX_CLASS
885 // Find prefix class, if any
886 dhcpv6_for_each_option(&prefix[1], odata + olen,
887 stype, slen, sdata)
888 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
889 entry.class = sdata[0] << 8 | sdata[1];
890 #endif
891
892 // Parse PD-exclude
893 bool ok = true;
894 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
895 odata + olen, stype, slen, sdata) {
896 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
897 continue;
898
899 uint8_t elen = sdata[0];
900 if (elen > 64)
901 elen = 64;
902
903 if (elen <= 32 || elen <= entry.length) {
904 ok = false;
905 continue;
906 }
907
908
909 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
910 if (slen <= bytes) {
911 ok = false;
912 continue;
913 }
914
915 uint32_t exclude = 0;
916 do {
917 exclude = exclude << 8 | sdata[bytes];
918 } while (--bytes);
919
920 exclude >>= 8 - ((elen - entry.length) % 8);
921 exclude <<= 64 - elen;
922
923 // Abusing router & priority fields for exclusion
924 entry.router = entry.target;
925 entry.router.s6_addr32[1] |= htonl(exclude);
926 entry.priority = elen;
927 }
928
929 if (ok)
930 odhcp6c_update_entry(STATE_IA_PD, &entry);
931
932 entry.priority = 0;
933 memset(&entry.router, 0, sizeof(entry.router));
934 } else if (otype == DHCPV6_OPT_IA_ADDR) {
935 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
936 if (olen + 4U < sizeof(*addr))
937 continue;
938
939 entry.preferred = ntohl(addr->preferred);
940 entry.valid = ntohl(addr->valid);
941
942 if (entry.preferred > entry.valid)
943 continue;
944
945 entry.length = 128;
946 entry.target = addr->addr;
947
948 #ifdef EXT_PREFIX_CLASS
949 uint16_t stype, slen;
950 uint8_t *sdata;
951 // Find prefix class, if any
952 dhcpv6_for_each_option(&addr[1], odata + olen,
953 stype, slen, sdata)
954 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
955 entry.class = sdata[0] << 8 | sdata[1];
956 #endif
957
958 odhcp6c_update_entry(STATE_IA_NA, &entry);
959 }
960 if (entry.valid > 0 && timeout > entry.valid)
961 timeout = entry.valid;
962 }
963
964 return timeout;
965 }
Openwrt DHCPv6 Client