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Fix compilation on 64-bit platforms
[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 int dhcpv6_parse_ia(void *opt, void *end);
50
51 static int dhcpv6_calc_refresh_timers(void);
52 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
53 const uint16_t code, const void *status_msg, const int len,
54 int *ret);
55 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
56 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
57 const void *status_msg, const int len,
58 bool handled_status_codes[_DHCPV6_Status_Max],
59 int *ret);
60
61 static reply_handler dhcpv6_handle_reply;
62 static reply_handler dhcpv6_handle_advert;
63 static reply_handler dhcpv6_handle_rebind_reply;
64 static reply_handler dhcpv6_handle_reconfigure;
65 static int dhcpv6_commit_advert(void);
66
67
68
69 // RFC 3315 - 5.5 Timeout and Delay values
70 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
71 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
72 dhcpv6_handle_reconfigure, NULL},
73 [DHCPV6_MSG_SOLICIT] = {true, 1, 3600, 0, "SOLICIT",
74 dhcpv6_handle_advert, dhcpv6_commit_advert},
75 [DHCPV6_MSG_REQUEST] = {true, 1, 30, 10, "REQUEST",
76 dhcpv6_handle_reply, NULL},
77 [DHCPV6_MSG_RENEW] = {false, 10, 600, 0, "RENEW",
78 dhcpv6_handle_reply, NULL},
79 [DHCPV6_MSG_REBIND] = {false, 10, 600, 0, "REBIND",
80 dhcpv6_handle_rebind_reply, NULL},
81 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
82 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
83 [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, 0, "INFOREQ",
84 dhcpv6_handle_reply, NULL},
85 };
86
87
88 // Sockets
89 static int sock = -1;
90 static int ifindex = -1;
91 static int64_t t1 = 0, t2 = 0, t3 = 0;
92
93 // IA states
94 static int request_prefix = -1;
95 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
96 static bool accept_reconfig = false;
97
98 // Reconfigure key
99 static uint8_t reconf_key[16];
100
101
102
103 int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
104 {
105 request_prefix = request_pd;
106 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
107
108 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
109
110 // Detect interface
111 struct ifreq ifr;
112 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
113 if (ioctl(sock, SIOCGIFINDEX, &ifr))
114 return -1;
115 ifindex = ifr.ifr_ifindex;
116
117 // Create client DUID
118 size_t client_id_len;
119 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
120 if (client_id_len == 0) {
121 ioctl(sock, SIOCGIFHWADDR, &ifr);
122 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
123 DHCPV6_DUID_LLADDR, 0, 1};
124 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
125
126 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
127 struct ifreq ifs[100], *ifp, *ifend;
128 struct ifconf ifc;
129 ifc.ifc_req = ifs;
130 ifc.ifc_len = sizeof(ifs);
131
132 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
133 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
134 // If our interface doesn't have an address...
135 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
136 for (ifp = ifc.ifc_req; ifp < ifend &&
137 !memcmp(&duid[8], zero, 6); ifp++) {
138 memcpy(ifr.ifr_name, ifp->ifr_name,
139 sizeof(ifr.ifr_name));
140 ioctl(sock, SIOCGIFHWADDR, &ifr);
141 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
142 ETHER_ADDR_LEN);
143 }
144 }
145
146 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
147 }
148
149 // Create ORO
150 uint16_t oro[] = {
151 htons(DHCPV6_OPT_SIP_SERVER_D),
152 htons(DHCPV6_OPT_SIP_SERVER_A),
153 htons(DHCPV6_OPT_DNS_SERVERS),
154 htons(DHCPV6_OPT_DNS_DOMAIN),
155 htons(DHCPV6_OPT_NTP_SERVER),
156 htons(DHCPV6_OPT_SIP_SERVER_A),
157 htons(DHCPV6_OPT_AFTR_NAME),
158 htons(DHCPV6_OPT_PD_EXCLUDE),
159 #ifdef EXT_PREFIX_CLASS
160 htons(DHCPV6_OPT_PREFIX_CLASS),
161 #endif
162 };
163 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
164
165
166 // Configure IPv6-options
167 int val = 1;
168 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
169 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
170 val = 0;
171 setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
172 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
173
174 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
175 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
176 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
177 return -1;
178
179 return 0;
180 }
181
182
183 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
184 {
185 na_mode = na;
186 pd_mode = pd;
187 }
188
189
190 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
191 {
192 // Build FQDN
193 char fqdn_buf[256];
194 gethostname(fqdn_buf, sizeof(fqdn_buf));
195 struct {
196 uint16_t type;
197 uint16_t len;
198 uint8_t flags;
199 uint8_t data[256];
200 } fqdn;
201 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
202 sizeof(fqdn.data), NULL, NULL);
203 fqdn.type = htons(DHCPV6_OPT_FQDN);
204 fqdn.len = htons(fqdn_len - 4);
205 fqdn.flags = 0;
206
207
208 // Build Client ID
209 size_t cl_id_len;
210 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
211
212 // Get Server ID
213 size_t srv_id_len;
214 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
215
216 // Build IA_PDs
217 size_t ia_pd_entries, ia_pd_len = 0;
218 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
219 ia_pd_entries /= sizeof(*e);
220 struct dhcpv6_ia_hdr hdr_ia_pd = {
221 htons(DHCPV6_OPT_IA_PD),
222 htons(sizeof(hdr_ia_pd) - 4),
223 1, 0, 0
224 };
225
226
227 uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
228 for (size_t i = 0; i < ia_pd_entries; ++i) {
229 uint8_t ex_len = 0;
230 if (e[i].priority > 0)
231 ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
232
233 struct dhcpv6_ia_prefix p = {
234 .type = htons(DHCPV6_OPT_IA_PREFIX),
235 .len = htons(sizeof(p) - 4U + ex_len),
236 .prefix = e[i].length,
237 .addr = e[i].target
238 };
239
240 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
241 ia_pd_len += sizeof(p);
242
243 if (ex_len) {
244 ia_pd[ia_pd_len++] = 0;
245 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
246 ia_pd[ia_pd_len++] = 0;
247 ia_pd[ia_pd_len++] = ex_len - 4;
248 ia_pd[ia_pd_len++] = e[i].priority;
249
250 uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
251 excl >>= (64 - e[i].priority);
252 excl <<= 8 - ((e[i].priority - e[i].length) % 8);
253
254 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
255 ia_pd[ia_pd_len + i] = excl & 0xff;
256 ia_pd_len += ex_len - 5;
257 }
258 }
259
260 struct dhcpv6_ia_prefix pref = {
261 .type = htons(DHCPV6_OPT_IA_PREFIX),
262 .len = htons(25), .prefix = request_prefix
263 };
264 if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
265 ia_pd = (uint8_t*)&pref;
266 ia_pd_len = sizeof(pref);
267 }
268 hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
269
270 // Build IA_NAs
271 size_t ia_na_entries, ia_na_len = 0;
272 void *ia_na = NULL;
273 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
274 ia_na_entries /= sizeof(*e);
275
276 struct dhcpv6_ia_hdr hdr_ia_na = {
277 htons(DHCPV6_OPT_IA_NA),
278 htons(sizeof(hdr_ia_na) - 4),
279 1, 0, 0
280 };
281
282 struct dhcpv6_ia_addr pa[ia_na_entries];
283 for (size_t i = 0; i < ia_na_entries; ++i) {
284 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
285 pa[i].len = htons(sizeof(pa[i]) - 4U);
286 pa[i].addr = e[i].target;
287 pa[i].preferred = 0;
288 pa[i].valid = 0;
289 }
290
291 ia_na = pa;
292 ia_na_len = sizeof(pa);
293 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
294
295 // Reconfigure Accept
296 struct {
297 uint16_t type;
298 uint16_t length;
299 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
300
301 // Request Information Refresh
302 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
303
304 // Prepare Header
305 size_t oro_len;
306 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
307 struct {
308 uint8_t type;
309 uint8_t trid[3];
310 uint16_t elapsed_type;
311 uint16_t elapsed_len;
312 uint16_t elapsed_value;
313 uint16_t oro_type;
314 uint16_t oro_len;
315 } hdr = {
316 type, {trid[0], trid[1], trid[2]},
317 htons(DHCPV6_OPT_ELAPSED), htons(2),
318 htons((ecs > 0xffff) ? 0xffff : ecs),
319 htons(DHCPV6_OPT_ORO), htons(oro_len),
320 };
321
322 struct iovec iov[] = {
323 {&hdr, sizeof(hdr)},
324 {oro, oro_len},
325 {&oro_refresh, 0},
326 {cl_id, cl_id_len},
327 {srv_id, srv_id_len},
328 {&reconf_accept, sizeof(reconf_accept)},
329 {&fqdn, fqdn_len},
330 {&hdr_ia_na, sizeof(hdr_ia_na)},
331 {ia_na, ia_na_len},
332 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
333 {ia_pd, ia_pd_len},
334 };
335
336 size_t cnt = ARRAY_SIZE(iov);
337 if (type == DHCPV6_MSG_INFO_REQ) {
338 cnt = 5;
339 iov[2].iov_len = sizeof(oro_refresh);
340 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
341 } else if (!request_prefix) {
342 cnt = 9;
343 }
344
345 // Disable IAs if not used
346 if (type != DHCPV6_MSG_SOLICIT) {
347 iov[5].iov_len = 0;
348 if (ia_na_len == 0)
349 iov[7].iov_len = 0;
350 if (ia_pd_len == 0)
351 iov[9].iov_len = 0;
352 }
353
354 if (na_mode == IA_MODE_NONE)
355 iov[7].iov_len = 0;
356
357 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
358 0, ALL_DHCPV6_RELAYS, ifindex};
359 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
360
361 sendmsg(sock, &msg, 0);
362 }
363
364
365 static int64_t dhcpv6_rand_delay(int64_t time)
366 {
367 int random;
368 odhcp6c_random(&random, sizeof(random));
369 return (time * ((int64_t)random % 1000LL)) / 10000LL;
370 }
371
372
373 int dhcpv6_request(enum dhcpv6_msg type)
374 {
375 uint8_t buf[1536], rc = 0;
376 uint64_t timeout = UINT32_MAX;
377 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
378
379 if (retx->delay) {
380 struct timespec ts = {0, 0};
381 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
382 nanosleep(&ts, NULL);
383 }
384
385 if (type == DHCPV6_MSG_UNKNOWN)
386 timeout = t1;
387 else if (type == DHCPV6_MSG_RENEW)
388 timeout = (t2 > t1) ? t2 - t1 : 0;
389 else if (type == DHCPV6_MSG_REBIND)
390 timeout = (t3 > t2) ? t3 - t2 : 0;
391
392 if (timeout == 0)
393 return -1;
394
395 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
396 retx->name, (unsigned long long)timeout, retx->max_rc);
397
398 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
399
400 // Generate transaction ID
401 uint8_t trid[3] = {0, 0, 0};
402 if (type != DHCPV6_MSG_UNKNOWN)
403 odhcp6c_random(trid, sizeof(trid));
404 ssize_t len = -1;
405 int64_t rto = 0;
406
407 do {
408 if (rto == 0) {
409 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
410
411 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
412 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
413 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
414
415 rto = (retx->init_timeo * 1000 + delay);
416 }
417 else
418 rto = (2 * rto + dhcpv6_rand_delay(rto));
419
420 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
421 rto = retx->max_timeo * 1000 +
422 dhcpv6_rand_delay(retx->max_timeo * 1000);
423
424 // Calculate end for this round and elapsed time
425 uint64_t round_end = round_start + rto;
426 elapsed = round_start - start;
427
428 // Don't wait too long
429 if (round_end - start > timeout * 1000)
430 round_end = timeout * 1000 + start;
431
432 // Built and send package
433 if (type != DHCPV6_MSG_UNKNOWN) {
434 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
435 retx->name, (unsigned long long)elapsed, rc);
436 dhcpv6_send(type, trid, elapsed / 10);
437 rc++;
438 }
439
440 // Receive rounds
441 for (; len < 0 && round_start < round_end;
442 round_start = odhcp6c_get_milli_time()) {
443 // Check for pending signal
444 if (odhcp6c_signal_process())
445 return -1;
446
447 // Set timeout for receiving
448 uint64_t t = round_end - round_start;
449 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
450 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
451 &timeout, sizeof(timeout));
452
453 // Receive cycle
454 len = recv(sock, buf, sizeof(buf), 0);
455
456 if (!dhcpv6_response_is_valid(buf, len, trid, type))
457 len = -1;
458
459 if (len > 0) {
460 uint8_t *opt = &buf[4];
461 uint8_t *opt_end = opt + len - 4;
462
463 round_start = odhcp6c_get_milli_time();
464 elapsed = round_start - start;
465 syslog(LOG_NOTICE, "Got a valid reply after "
466 "%llums", (unsigned long long)elapsed);
467
468 if (retx->handler_reply)
469 len = retx->handler_reply(
470 type, rc, opt, opt_end);
471
472 if (len > 0 && round_end - round_start > 1000)
473 round_end = 1000 + round_start;
474 }
475 }
476
477 // Allow
478 if (retx->handler_finish)
479 len = retx->handler_finish();
480 } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
481
482 return len;
483 }
484
485
486 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
487 const uint8_t transaction[3], enum dhcpv6_msg type)
488 {
489 const struct dhcpv6_header *rep = buf;
490 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
491 transaction, sizeof(rep->tr_id)))
492 return false; // Invalid reply
493
494 if (type == DHCPV6_MSG_SOLICIT) {
495 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
496 rep->msg_type != DHCPV6_MSG_REPLY)
497 return false;
498 } else if (type == DHCPV6_MSG_UNKNOWN) {
499 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
500 return false;
501 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
502 return false;
503 }
504
505 uint8_t *end = ((uint8_t*)buf) + len, *odata;
506 uint16_t otype, olen;
507 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
508
509 size_t client_id_len, server_id_len;
510 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
511 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
512
513 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
514 if (otype == DHCPV6_OPT_CLIENTID) {
515 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
516 &odata[-4], client_id, client_id_len);
517 } else if (otype == DHCPV6_OPT_SERVERID) {
518 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
519 &odata[-4], server_id, server_id_len);
520 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
521 sizeof(struct dhcpv6_auth_reconfigure)) {
522 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
523 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
524 continue;
525
526 md5_state_t md5;
527 uint8_t serverhash[16], secretbytes[16], hash[16];
528 memcpy(serverhash, r->key, sizeof(serverhash));
529 memset(r->key, 0, sizeof(r->key));
530 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
531
532 for (size_t i = 0; i < sizeof(secretbytes); ++i)
533 secretbytes[i] ^= 0x36;
534
535 md5_init(&md5);
536 md5_append(&md5, secretbytes, sizeof(secretbytes));
537 md5_append(&md5, buf, len);
538 md5_finish(&md5, hash);
539
540 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
541 secretbytes[i] ^= 0x36;
542 secretbytes[i] ^= 0x5c;
543 }
544
545 md5_init(&md5);
546 md5_append(&md5, secretbytes, sizeof(secretbytes));
547 md5_append(&md5, hash, 16);
548 md5_finish(&md5, hash);
549
550 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
551 }
552 }
553
554 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
555 return false;
556
557 return clientid_ok && (serverid_ok || server_id_len == 0);
558 }
559
560
561 int dhcpv6_poll_reconfigure(void)
562 {
563 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
564 if (ret != -1)
565 ret = dhcpv6_request(ret);
566
567 return ret;
568 }
569
570
571 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
572 const void *opt, const void *end)
573 {
574 // TODO: should verify the reconfigure message
575 uint16_t otype, olen;
576 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
577 dhcpv6_for_each_option(opt, end, otype, olen, odata)
578 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
579 odata[0] == DHCPV6_MSG_RENEW ||
580 odata[0] == DHCPV6_MSG_INFO_REQ))
581 msg = odata[0];
582
583 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
584 return msg;
585 }
586
587
588 // Collect all advertised servers
589 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
590 const void *opt, const void *end)
591 {
592 uint16_t olen, otype;
593 uint8_t *odata, pref = 0;
594 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
595 bool have_na = false;
596 int have_pd = 0;
597
598 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
599 if (orig == DHCPV6_MSG_SOLICIT &&
600 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
601 olen > sizeof(struct dhcpv6_ia_hdr)) {
602 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
603 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
604 }
605
606 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
607 memcpy(cand.duid, odata, olen);
608 cand.duid_len = olen;
609 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
610 int error = ((int)odata[0] << 8 | (int)odata[1]);
611
612 switch (error) {
613 case DHCPV6_NoPrefixAvail:
614 // Status code on global level
615 if (pd_mode == IA_MODE_FORCE)
616 return -1;
617 cand.preference -= 2000;
618 break;
619
620 case DHCPV6_NoAddrsAvail:
621 // Status code on global level
622 if (na_mode == IA_MODE_FORCE)
623 return -1;
624 break;
625
626 default :
627 break;
628 }
629 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
630 cand.preference >= 0) {
631 cand.preference = pref = odata[0];
632 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
633 cand.wants_reconfigure = true;
634 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
635 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
636 uint8_t *oend = odata + olen, *d;
637 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
638 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
639 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
640 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
641 have_pd = p->prefix;
642 }
643 }
644 } else if (otype == DHCPV6_OPT_IA_NA) {
645 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
646 uint8_t *oend = odata + olen, *d;
647 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
648 if (otype == DHCPV6_OPT_IA_ADDR)
649 have_na = true;
650 }
651 }
652
653 if ((!have_na && na_mode == IA_MODE_FORCE) ||
654 (!have_pd && pd_mode == IA_MODE_FORCE))
655 return -1;
656
657 if (na_mode != IA_MODE_NONE && !have_na) {
658 cand.has_noaddravail = true;
659 cand.preference -= 1000;
660 }
661
662 if (pd_mode != IA_MODE_NONE) {
663 if (have_pd)
664 cand.preference += 2000 + (128 - have_pd);
665 else
666 cand.preference -= 2000;
667 }
668
669 if (cand.duid_len > 0) {
670 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
671 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
672 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
673 }
674
675 if (orig == DHCPV6_MSG_SOLICIT) {
676 odhcp6c_clear_state(STATE_IA_NA);
677 odhcp6c_clear_state(STATE_IA_PD);
678 }
679
680 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
681 }
682
683
684 static int dhcpv6_commit_advert(void)
685 {
686 size_t cand_len;
687 struct dhcpv6_server_cand *c = NULL, *cand =
688 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
689
690 bool retry = false;
691 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
692 if (cand[i].has_noaddravail)
693 retry = true; // We want to try again
694
695 if (!c || c->preference < cand[i].preference)
696 c = &cand[i];
697 }
698
699 if (retry && na_mode == IA_MODE_TRY) {
700 // We give it a second try without the IA_NA
701 na_mode = IA_MODE_NONE;
702 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
703 }
704
705 if (c) {
706 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
707 htons(c->duid_len)};
708 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
709 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
710 accept_reconfig = c->wants_reconfigure;
711 if (c->ia_na_len)
712 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
713 if (c->ia_pd_len)
714 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
715 }
716
717 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
718 free(cand[i].ia_na);
719 free(cand[i].ia_pd);
720 }
721 odhcp6c_clear_state(STATE_SERVER_CAND);
722
723 if (!c)
724 return -1;
725 else if ((request_prefix && c->ia_pd_len) || (na_mode != IA_MODE_NONE && c->ia_na_len))
726 return DHCPV6_STATEFUL;
727 else
728 return DHCPV6_STATELESS;
729 }
730
731
732 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
733 const void *opt, const void *end)
734 {
735 dhcpv6_handle_advert(orig, rc, opt, end);
736 if (dhcpv6_commit_advert() < 0) {
737 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
738 return -1;
739 }
740
741 return dhcpv6_handle_reply(orig, rc, opt, end);
742 }
743
744
745 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
746 const void *opt, const void *end)
747 {
748 uint8_t *odata;
749 uint16_t otype, olen;
750 uint32_t refresh = UINT32_MAX;
751 int ret = 1;
752 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
753
754 odhcp6c_expire();
755
756 if (orig == DHCPV6_MSG_UNKNOWN) {
757 static time_t last_update = 0;
758 time_t now = odhcp6c_get_milli_time() / 1000;
759
760 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
761 last_update = now;
762
763 t1 -= elapsed;
764 t2 -= elapsed;
765 t3 -= elapsed;
766
767 if (t1 < 0)
768 t1 = 0;
769
770 if (t2 < 0)
771 t2 = 0;
772
773 if (t3 < 0)
774 t3 = 0;
775 }
776
777 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
778 // Delete NA and PD we have in the state from the Advert
779 odhcp6c_clear_state(STATE_IA_NA);
780 odhcp6c_clear_state(STATE_IA_PD);
781 }
782
783 if (opt) {
784 odhcp6c_clear_state(STATE_DNS);
785 odhcp6c_clear_state(STATE_SEARCH);
786 odhcp6c_clear_state(STATE_SNTP_IP);
787 odhcp6c_clear_state(STATE_SNTP_FQDN);
788 odhcp6c_clear_state(STATE_SIP_IP);
789 odhcp6c_clear_state(STATE_SIP_FQDN);
790 odhcp6c_clear_state(STATE_AFTR_NAME);
791 }
792
793 // Parse and find all matching IAs
794 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
795 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
796 && olen > sizeof(struct dhcpv6_ia_hdr)) {
797 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
798
799 // Test ID
800 if (ia_hdr->iaid != 1)
801 continue;
802
803 uint16_t code = DHCPV6_Success;
804 uint16_t stype, slen;
805 uint8_t *sdata;
806 // Get and handle status code
807 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
808 stype, slen, sdata) {
809 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
810 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
811 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
812
813 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
814
815 if (code == DHCPV6_Success)
816 continue;
817
818 dhcpv6_handle_ia_status_code(orig, ia_hdr,
819 code, mdata, mlen, handled_status_codes, &ret);
820
821
822 if (ret > 0)
823 return ret;
824 break;
825 }
826 }
827
828 if (code != DHCPV6_Success)
829 continue;
830
831 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
832 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
833 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
834 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
835 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
836
837 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
838 }
839 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
840 if (olen % 16 == 0)
841 odhcp6c_add_state(STATE_DNS, odata, olen);
842 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
843 odhcp6c_add_state(STATE_SEARCH, odata, olen);
844 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
845 uint16_t stype, slen;
846 uint8_t *sdata;
847 // Test status and bail if error
848 dhcpv6_for_each_option(odata, odata + olen,
849 stype, slen, sdata) {
850 if (slen == 16 && (stype == NTP_MC_ADDR ||
851 stype == NTP_SRV_ADDR))
852 odhcp6c_add_state(STATE_SNTP_IP,
853 sdata, slen);
854 else if (slen > 0 && stype == NTP_SRV_FQDN)
855 odhcp6c_add_state(STATE_SNTP_FQDN,
856 sdata, slen);
857 }
858 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
859 if (olen == 16)
860 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
861 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
862 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
863 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
864 refresh = ntohl(*((uint32_t*)odata));
865 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
866 sizeof(struct dhcpv6_auth_reconfigure)) {
867 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
868 if (r->protocol == 3 && r->algorithm == 1 &&
869 r->reconf_type == 1)
870 memcpy(reconf_key, r->key, sizeof(r->key));
871 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
872 size_t cur_len;
873 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
874 if (cur_len == 0)
875 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
876 } else if (otype != DHCPV6_OPT_CLIENTID &&
877 otype != DHCPV6_OPT_SERVERID) {
878 odhcp6c_add_state(STATE_CUSTOM_OPTS,
879 &odata[-4], olen + 4);
880 }
881 }
882
883 if (orig != DHCPV6_MSG_INFO_REQ) {
884 // Update refresh timers if no fatal status code was received
885 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
886 switch (orig) {
887 case DHCPV6_MSG_RENEW:
888 // Send further renews if T1 is not set
889 if (!t1)
890 ret = -1;
891 break;
892 case DHCPV6_MSG_REBIND:
893 // Send further rebinds if T1 and T2 is not set
894 if (!t1 && !t2)
895 ret = -1;
896 break;
897
898 default :
899 break;
900 }
901 }
902 }
903 else if (ret > 0)
904 t1 = refresh;
905
906 return ret;
907 }
908
909
910 static int dhcpv6_parse_ia(void *opt, void *end)
911 {
912 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
913 int parsed_ia = 0;
914 uint32_t t1, t2;
915 uint16_t otype, olen;
916 uint8_t *odata;
917
918 t1 = ntohl(ia_hdr->t1);
919 t2 = ntohl(ia_hdr->t2);
920
921 if (t1 > t2)
922 return 0;
923
924 // Update address IA
925 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
926 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
927 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
928
929 if (otype == DHCPV6_OPT_IA_PREFIX) {
930 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
931 if (olen + 4U < sizeof(*prefix))
932 continue;
933
934 entry.valid = ntohl(prefix->valid);
935 entry.preferred = ntohl(prefix->preferred);
936
937 if (entry.preferred > entry.valid)
938 continue;
939
940 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
941 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
942 if (entry.t1 > entry.t2)
943 entry.t1 = entry.t2;
944
945 entry.length = prefix->prefix;
946 entry.target = prefix->addr;
947 uint16_t stype, slen;
948 uint8_t *sdata;
949
950 #ifdef EXT_PREFIX_CLASS
951 // Find prefix class, if any
952 dhcpv6_for_each_option(&prefix[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 // Parse PD-exclude
959 bool ok = true;
960 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
961 odata + olen, stype, slen, sdata) {
962 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
963 continue;
964
965 uint8_t elen = sdata[0];
966 if (elen > 64)
967 elen = 64;
968
969 if (elen <= 32 || elen <= entry.length) {
970 ok = false;
971 continue;
972 }
973
974
975 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
976 if (slen <= bytes) {
977 ok = false;
978 continue;
979 }
980
981 uint32_t exclude = 0;
982 do {
983 exclude = exclude << 8 | sdata[bytes];
984 } while (--bytes);
985
986 exclude >>= 8 - ((elen - entry.length) % 8);
987 exclude <<= 64 - elen;
988
989 // Abusing router & priority fields for exclusion
990 entry.router = entry.target;
991 entry.router.s6_addr32[1] |= htonl(exclude);
992 entry.priority = elen;
993 }
994
995 if (ok) {
996 odhcp6c_update_entry(STATE_IA_PD, &entry);
997 parsed_ia++;
998 }
999
1000 entry.priority = 0;
1001 memset(&entry.router, 0, sizeof(entry.router));
1002 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1003 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1004 if (olen + 4U < sizeof(*addr))
1005 continue;
1006
1007 entry.preferred = ntohl(addr->preferred);
1008 entry.valid = ntohl(addr->valid);
1009
1010 if (entry.preferred > entry.valid)
1011 continue;
1012
1013 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1014 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1015 if (entry.t1 > entry.t2)
1016 entry.t1 = entry.t2;
1017
1018 entry.length = 128;
1019 entry.target = addr->addr;
1020
1021 #ifdef EXT_PREFIX_CLASS
1022 uint16_t stype, slen;
1023 uint8_t *sdata;
1024 // Find prefix class, if any
1025 dhcpv6_for_each_option(&addr[1], odata + olen,
1026 stype, slen, sdata)
1027 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1028 entry.class = sdata[0] << 8 | sdata[1];
1029 #endif
1030
1031 odhcp6c_update_entry(STATE_IA_NA, &entry);
1032 parsed_ia++;
1033 }
1034 }
1035 return parsed_ia;
1036 }
1037
1038
1039 static int dhcpv6_calc_refresh_timers(void)
1040 {
1041 struct odhcp6c_entry *e;
1042 size_t ia_na_entries, ia_pd_entries, i;
1043 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1044
1045 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1046 ia_na_entries /= sizeof(*e);
1047 for (i = 0; i < ia_na_entries; i++) {
1048 if (e[i].t1 < l_t1)
1049 l_t1 = e[i].t1;
1050
1051 if (e[i].t2 < l_t2)
1052 l_t2 = e[i].t2;
1053
1054 if (e[i].valid > l_t3)
1055 l_t3 = e[i].valid;
1056 }
1057
1058 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1059 ia_pd_entries /= sizeof(*e);
1060 for (i = 0; i < ia_pd_entries; i++) {
1061 if (e[i].t1 < l_t1)
1062 l_t1 = e[i].t1;
1063
1064 if (e[i].t2 < l_t2)
1065 l_t2 = e[i].t2;
1066
1067 if (e[i].valid > l_t3)
1068 l_t3 = e[i].valid;
1069 }
1070
1071 if (ia_pd_entries || ia_na_entries) {
1072 t1 = l_t1;
1073 t2 = l_t2;
1074 t3 = l_t3;
1075 }
1076
1077 return (int)(ia_pd_entries + ia_na_entries);
1078 }
1079
1080
1081 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1082 const void *status_msg, const int len)
1083 {
1084 uint8_t buf[len + 3];
1085
1086 memset(buf, 0, sizeof(buf));
1087 if (len) {
1088 buf[0] = '(';
1089 memcpy(&buf[1], status_msg, len);
1090 buf[len + 1] = ')';
1091 }
1092
1093 syslog(LOG_WARNING, "Server returned %s status %i %s",
1094 scope, code, buf);
1095 }
1096
1097
1098 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1099 const uint16_t code, const void *status_msg, const int len,
1100 int *ret)
1101 {
1102 dhcpv6_log_status_code(code, "message", status_msg, len);
1103
1104 switch (code) {
1105 case DHCPV6_UnspecFail:
1106 // Generic failure
1107 *ret = 0;
1108 break;
1109
1110 case DHCPV6_UseMulticast:
1111 // TODO handle multicast status code
1112 break;
1113
1114 case DHCPV6_NoAddrsAvail:
1115 case DHCPV6_NoPrefixAvail:
1116 if (orig == DHCPV6_MSG_REQUEST)
1117 *ret = 0; // Failure
1118 break;
1119
1120 default:
1121 break;
1122 }
1123 }
1124
1125
1126 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1127 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1128 const void *status_msg, const int len,
1129 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1130 {
1131 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1132 "IA_NA" : "IA_PD", status_msg, len);
1133
1134 switch (code) {
1135 case DHCPV6_NoBinding:
1136 switch (orig) {
1137 case DHCPV6_MSG_RENEW:
1138 case DHCPV6_MSG_REBIND:
1139 if ((*ret > 0) && !handled_status_codes[code])
1140 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1141 break;
1142
1143 default:
1144 break;
1145 }
1146 break;
1147
1148 case DHCPV6_NoAddrsAvail:
1149 case DHCPV6_NoPrefixAvail:
1150 switch (orig) {
1151 case DHCPV6_MSG_REQUEST:
1152 if (*ret != 0)
1153 *ret = 0;
1154 break;
1155 default:
1156 break;
1157 }
1158 break;
1159
1160 case DHCPV6_NotOnLink:
1161 // TODO handle not onlink in case of confirm
1162 break;
1163
1164 default:
1165 break;
1166 }
1167 }
Openwrt DHCPv6 Client