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odhpc6c: status code support in reply
[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)", retx->name, timeout, retx->max_rc);
396
397 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
398
399 // Generate transaction ID
400 uint8_t trid[3] = {0, 0, 0};
401 if (type != DHCPV6_MSG_UNKNOWN)
402 odhcp6c_random(trid, sizeof(trid));
403 ssize_t len = -1;
404 int64_t rto = 0;
405
406 do {
407 if (rto == 0) {
408 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
409
410 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
411 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
412 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
413
414 rto = (retx->init_timeo * 1000 + delay);
415 }
416 else
417 rto = (2 * rto + dhcpv6_rand_delay(rto));
418
419 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
420 rto = retx->max_timeo * 1000 +
421 dhcpv6_rand_delay(retx->max_timeo * 1000);
422
423 // Calculate end for this round and elapsed time
424 uint64_t round_end = round_start + rto;
425 elapsed = round_start - start;
426
427 // Don't wait too long
428 if (round_end - start > timeout * 1000)
429 round_end = timeout * 1000 + start;
430
431 // Built and send package
432 if (type != DHCPV6_MSG_UNKNOWN) {
433 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)", retx->name, elapsed, rc);
434 dhcpv6_send(type, trid, elapsed / 10);
435 rc++;
436 }
437
438 // Receive rounds
439 for (; len < 0 && round_start < round_end;
440 round_start = odhcp6c_get_milli_time()) {
441 // Check for pending signal
442 if (odhcp6c_signal_process())
443 return -1;
444
445 // Set timeout for receiving
446 uint64_t t = round_end - round_start;
447 struct timeval timeout = {t / 1000, (t % 1000) * 1000};
448 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
449 &timeout, sizeof(timeout));
450
451 // Receive cycle
452 len = recv(sock, buf, sizeof(buf), 0);
453
454 if (!dhcpv6_response_is_valid(buf, len, trid, type))
455 len = -1;
456
457 if (len > 0) {
458 uint8_t *opt = &buf[4];
459 uint8_t *opt_end = opt + len - 4;
460
461 round_start = odhcp6c_get_milli_time();
462 elapsed = round_start - start;
463 syslog(LOG_NOTICE, "Got a valid reply after "
464 "%llums", elapsed);
465
466 if (retx->handler_reply)
467 len = retx->handler_reply(
468 type, rc, opt, opt_end);
469
470 if (len > 0 && round_end - round_start > 1000)
471 round_end = 1000 + round_start;
472 }
473 }
474
475 // Allow
476 if (retx->handler_finish)
477 len = retx->handler_finish();
478 } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
479
480 return len;
481 }
482
483
484 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
485 const uint8_t transaction[3], enum dhcpv6_msg type)
486 {
487 const struct dhcpv6_header *rep = buf;
488 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
489 transaction, sizeof(rep->tr_id)))
490 return false; // Invalid reply
491
492 if (type == DHCPV6_MSG_SOLICIT) {
493 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
494 rep->msg_type != DHCPV6_MSG_REPLY)
495 return false;
496 } else if (type == DHCPV6_MSG_UNKNOWN) {
497 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
498 return false;
499 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
500 return false;
501 }
502
503 uint8_t *end = ((uint8_t*)buf) + len, *odata;
504 uint16_t otype, olen;
505 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
506
507 size_t client_id_len, server_id_len;
508 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
509 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
510
511 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
512 if (otype == DHCPV6_OPT_CLIENTID) {
513 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
514 &odata[-4], client_id, client_id_len);
515 } else if (otype == DHCPV6_OPT_SERVERID) {
516 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
517 &odata[-4], server_id, server_id_len);
518 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
519 sizeof(struct dhcpv6_auth_reconfigure)) {
520 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
521 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
522 continue;
523
524 md5_state_t md5;
525 uint8_t serverhash[16], secretbytes[16], hash[16];
526 memcpy(serverhash, r->key, sizeof(serverhash));
527 memset(r->key, 0, sizeof(r->key));
528 memcpy(secretbytes, reconf_key, sizeof(secretbytes));
529
530 for (size_t i = 0; i < sizeof(secretbytes); ++i)
531 secretbytes[i] ^= 0x36;
532
533 md5_init(&md5);
534 md5_append(&md5, secretbytes, sizeof(secretbytes));
535 md5_append(&md5, buf, len);
536 md5_finish(&md5, hash);
537
538 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
539 secretbytes[i] ^= 0x36;
540 secretbytes[i] ^= 0x5c;
541 }
542
543 md5_init(&md5);
544 md5_append(&md5, secretbytes, sizeof(secretbytes));
545 md5_append(&md5, hash, 16);
546 md5_finish(&md5, hash);
547
548 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
549 }
550 }
551
552 if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
553 return false;
554
555 return clientid_ok && (serverid_ok || server_id_len == 0);
556 }
557
558
559 int dhcpv6_poll_reconfigure(void)
560 {
561 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
562 if (ret != -1)
563 ret = dhcpv6_request(ret);
564
565 return ret;
566 }
567
568
569 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
570 const void *opt, const void *end)
571 {
572 // TODO: should verify the reconfigure message
573 uint16_t otype, olen;
574 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
575 dhcpv6_for_each_option(opt, end, otype, olen, odata)
576 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
577 odata[0] == DHCPV6_MSG_RENEW ||
578 odata[0] == DHCPV6_MSG_INFO_REQ))
579 msg = odata[0];
580
581 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
582 return msg;
583 }
584
585
586 // Collect all advertised servers
587 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
588 const void *opt, const void *end)
589 {
590 uint16_t olen, otype;
591 uint8_t *odata, pref = 0;
592 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
593 bool have_na = false;
594 int have_pd = 0;
595
596 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
597 if (orig == DHCPV6_MSG_SOLICIT &&
598 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
599 olen > sizeof(struct dhcpv6_ia_hdr)) {
600 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
601 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
602 }
603
604 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
605 memcpy(cand.duid, odata, olen);
606 cand.duid_len = olen;
607 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
608 int error = ((int)odata[0] << 8 | (int)odata[1]);
609
610 switch (error) {
611 case DHCPV6_NoPrefixAvail:
612 // Status code on global level
613 if (pd_mode == IA_MODE_FORCE)
614 return -1;
615 cand.preference -= 2000;
616 break;
617
618 case DHCPV6_NoAddrsAvail:
619 // Status code on global level
620 if (na_mode == IA_MODE_FORCE)
621 return -1;
622 break;
623
624 default :
625 break;
626 }
627 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
628 cand.preference >= 0) {
629 cand.preference = pref = odata[0];
630 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
631 cand.wants_reconfigure = true;
632 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
633 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
634 uint8_t *oend = odata + olen, *d;
635 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
636 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
637 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
638 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
639 have_pd = p->prefix;
640 }
641 }
642 } else if (otype == DHCPV6_OPT_IA_NA) {
643 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
644 uint8_t *oend = odata + olen, *d;
645 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
646 if (otype == DHCPV6_OPT_IA_ADDR)
647 have_na = true;
648 }
649 }
650
651 if ((!have_na && na_mode == IA_MODE_FORCE) ||
652 (!have_pd && pd_mode == IA_MODE_FORCE))
653 return -1;
654
655 if (na_mode != IA_MODE_NONE && !have_na) {
656 cand.has_noaddravail = true;
657 cand.preference -= 1000;
658 }
659
660 if (pd_mode != IA_MODE_NONE) {
661 if (have_pd)
662 cand.preference += 2000 + (128 - have_pd);
663 else
664 cand.preference -= 2000;
665 }
666
667 if (cand.duid_len > 0) {
668 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
669 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
670 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
671 }
672
673 if (orig == DHCPV6_MSG_SOLICIT) {
674 odhcp6c_clear_state(STATE_IA_NA);
675 odhcp6c_clear_state(STATE_IA_PD);
676 }
677
678 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
679 }
680
681
682 static int dhcpv6_commit_advert(void)
683 {
684 size_t cand_len;
685 struct dhcpv6_server_cand *c = NULL, *cand =
686 odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
687
688 bool retry = false;
689 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
690 if (cand[i].has_noaddravail)
691 retry = true; // We want to try again
692
693 if (!c || c->preference < cand[i].preference)
694 c = &cand[i];
695 }
696
697 if (retry && na_mode == IA_MODE_TRY) {
698 // We give it a second try without the IA_NA
699 na_mode = IA_MODE_NONE;
700 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
701 }
702
703 if (c) {
704 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
705 htons(c->duid_len)};
706 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
707 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
708 accept_reconfig = c->wants_reconfigure;
709 if (c->ia_na_len)
710 odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
711 if (c->ia_pd_len)
712 odhcp6c_add_state(STATE_IA_PD, c->ia_pd, c->ia_pd_len);
713 }
714
715 for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
716 free(cand[i].ia_na);
717 free(cand[i].ia_pd);
718 }
719 odhcp6c_clear_state(STATE_SERVER_CAND);
720
721 if (!c)
722 return -1;
723 else if ((request_prefix && c->ia_pd_len) || (na_mode != IA_MODE_NONE && c->ia_na_len))
724 return DHCPV6_STATEFUL;
725 else
726 return DHCPV6_STATELESS;
727 }
728
729
730 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
731 const void *opt, const void *end)
732 {
733 dhcpv6_handle_advert(orig, rc, opt, end);
734 if (dhcpv6_commit_advert() < 0) {
735 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
736 return -1;
737 }
738
739 return dhcpv6_handle_reply(orig, rc, opt, end);
740 }
741
742
743 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
744 const void *opt, const void *end)
745 {
746 uint8_t *odata;
747 uint16_t otype, olen;
748 uint32_t refresh = UINT32_MAX;
749 int ret = 1;
750 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
751
752 odhcp6c_expire();
753
754 if (orig == DHCPV6_MSG_UNKNOWN) {
755 static time_t last_update = 0;
756 time_t now = odhcp6c_get_milli_time() / 1000;
757
758 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
759 last_update = now;
760
761 t1 -= elapsed;
762 t2 -= elapsed;
763 t3 -= elapsed;
764
765 if (t1 < 0)
766 t1 = 0;
767
768 if (t2 < 0)
769 t2 = 0;
770
771 if (t3 < 0)
772 t3 = 0;
773 }
774
775 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
776 // Delete NA and PD we have in the state from the Advert
777 odhcp6c_clear_state(STATE_IA_NA);
778 odhcp6c_clear_state(STATE_IA_PD);
779 }
780
781 if (opt) {
782 odhcp6c_clear_state(STATE_DNS);
783 odhcp6c_clear_state(STATE_SEARCH);
784 odhcp6c_clear_state(STATE_SNTP_IP);
785 odhcp6c_clear_state(STATE_SNTP_FQDN);
786 odhcp6c_clear_state(STATE_SIP_IP);
787 odhcp6c_clear_state(STATE_SIP_FQDN);
788 odhcp6c_clear_state(STATE_AFTR_NAME);
789 }
790
791 // Parse and find all matching IAs
792 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
793 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
794 && olen > sizeof(struct dhcpv6_ia_hdr)) {
795 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
796
797 // Test ID
798 if (ia_hdr->iaid != 1)
799 continue;
800
801 uint16_t code = DHCPV6_Success;
802 uint16_t stype, slen;
803 uint8_t *sdata;
804 // Get and handle status code
805 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
806 stype, slen, sdata) {
807 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
808 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
809 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
810
811 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
812
813 if (code == DHCPV6_Success)
814 continue;
815
816 dhcpv6_handle_ia_status_code(orig, ia_hdr,
817 code, mdata, mlen, handled_status_codes, &ret);
818
819
820 if (ret > 0)
821 return ret;
822 break;
823 }
824 }
825
826 if (code != DHCPV6_Success)
827 continue;
828
829 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
830 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
831 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
832 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
833 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
834
835 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
836 }
837 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
838 if (olen % 16 == 0)
839 odhcp6c_add_state(STATE_DNS, odata, olen);
840 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
841 odhcp6c_add_state(STATE_SEARCH, odata, olen);
842 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
843 uint16_t stype, slen;
844 uint8_t *sdata;
845 // Test status and bail if error
846 dhcpv6_for_each_option(odata, odata + olen,
847 stype, slen, sdata) {
848 if (slen == 16 && (stype == NTP_MC_ADDR ||
849 stype == NTP_SRV_ADDR))
850 odhcp6c_add_state(STATE_SNTP_IP,
851 sdata, slen);
852 else if (slen > 0 && stype == NTP_SRV_FQDN)
853 odhcp6c_add_state(STATE_SNTP_FQDN,
854 sdata, slen);
855 }
856 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
857 if (olen == 16)
858 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
859 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
860 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
861 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
862 refresh = ntohl(*((uint32_t*)odata));
863 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
864 sizeof(struct dhcpv6_auth_reconfigure)) {
865 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
866 if (r->protocol == 3 && r->algorithm == 1 &&
867 r->reconf_type == 1)
868 memcpy(reconf_key, r->key, sizeof(r->key));
869 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
870 size_t cur_len;
871 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
872 if (cur_len == 0)
873 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
874 } else if (otype != DHCPV6_OPT_CLIENTID &&
875 otype != DHCPV6_OPT_SERVERID) {
876 odhcp6c_add_state(STATE_CUSTOM_OPTS,
877 &odata[-4], olen + 4);
878 }
879 }
880
881 if (orig != DHCPV6_MSG_INFO_REQ) {
882 // Update refresh timers if no fatal status code was received
883 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
884 switch (orig) {
885 case DHCPV6_MSG_RENEW:
886 // Send further renews if T1 is not set
887 if (!t1)
888 ret = -1;
889 break;
890 case DHCPV6_MSG_REBIND:
891 // Send further rebinds if T1 and T2 is not set
892 if (!t1 && !t2)
893 ret = -1;
894 break;
895
896 default :
897 break;
898 }
899 }
900 }
901 else if (ret > 0)
902 t1 = refresh;
903
904 return ret;
905 }
906
907
908 static int dhcpv6_parse_ia(void *opt, void *end)
909 {
910 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
911 int parsed_ia = 0;
912 uint32_t t1, t2;
913 uint16_t otype, olen;
914 uint8_t *odata;
915
916 t1 = ntohl(ia_hdr->t1);
917 t2 = ntohl(ia_hdr->t2);
918
919 if (t1 > t2)
920 return 0;
921
922 // Update address IA
923 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
924 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
925 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
926
927 if (otype == DHCPV6_OPT_IA_PREFIX) {
928 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
929 if (olen + 4U < sizeof(*prefix))
930 continue;
931
932 entry.valid = ntohl(prefix->valid);
933 entry.preferred = ntohl(prefix->preferred);
934
935 if (entry.preferred > entry.valid)
936 continue;
937
938 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
939 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
940 if (entry.t1 > entry.t2)
941 entry.t1 = entry.t2;
942
943 entry.length = prefix->prefix;
944 entry.target = prefix->addr;
945 uint16_t stype, slen;
946 uint8_t *sdata;
947
948 #ifdef EXT_PREFIX_CLASS
949 // Find prefix class, if any
950 dhcpv6_for_each_option(&prefix[1], odata + olen,
951 stype, slen, sdata)
952 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
953 entry.class = sdata[0] << 8 | sdata[1];
954 #endif
955
956 // Parse PD-exclude
957 bool ok = true;
958 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
959 odata + olen, stype, slen, sdata) {
960 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
961 continue;
962
963 uint8_t elen = sdata[0];
964 if (elen > 64)
965 elen = 64;
966
967 if (elen <= 32 || elen <= entry.length) {
968 ok = false;
969 continue;
970 }
971
972
973 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
974 if (slen <= bytes) {
975 ok = false;
976 continue;
977 }
978
979 uint32_t exclude = 0;
980 do {
981 exclude = exclude << 8 | sdata[bytes];
982 } while (--bytes);
983
984 exclude >>= 8 - ((elen - entry.length) % 8);
985 exclude <<= 64 - elen;
986
987 // Abusing router & priority fields for exclusion
988 entry.router = entry.target;
989 entry.router.s6_addr32[1] |= htonl(exclude);
990 entry.priority = elen;
991 }
992
993 if (ok) {
994 odhcp6c_update_entry(STATE_IA_PD, &entry);
995 parsed_ia++;
996 }
997
998 entry.priority = 0;
999 memset(&entry.router, 0, sizeof(entry.router));
1000 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1001 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1002 if (olen + 4U < sizeof(*addr))
1003 continue;
1004
1005 entry.preferred = ntohl(addr->preferred);
1006 entry.valid = ntohl(addr->valid);
1007
1008 if (entry.preferred > entry.valid)
1009 continue;
1010
1011 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1012 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1013 if (entry.t1 > entry.t2)
1014 entry.t1 = entry.t2;
1015
1016 entry.length = 128;
1017 entry.target = addr->addr;
1018
1019 #ifdef EXT_PREFIX_CLASS
1020 uint16_t stype, slen;
1021 uint8_t *sdata;
1022 // Find prefix class, if any
1023 dhcpv6_for_each_option(&addr[1], odata + olen,
1024 stype, slen, sdata)
1025 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1026 entry.class = sdata[0] << 8 | sdata[1];
1027 #endif
1028
1029 odhcp6c_update_entry(STATE_IA_NA, &entry);
1030 parsed_ia++;
1031 }
1032 }
1033 return parsed_ia;
1034 }
1035
1036
1037 static int dhcpv6_calc_refresh_timers(void)
1038 {
1039 struct odhcp6c_entry *e;
1040 size_t ia_na_entries, ia_pd_entries, i;
1041 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1042
1043 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1044 ia_na_entries /= sizeof(*e);
1045 for (i = 0; i < ia_na_entries; i++) {
1046 if (e[i].t1 < l_t1)
1047 l_t1 = e[i].t1;
1048
1049 if (e[i].t2 < l_t2)
1050 l_t2 = e[i].t2;
1051
1052 if (e[i].valid > l_t3)
1053 l_t3 = e[i].valid;
1054 }
1055
1056 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1057 ia_pd_entries /= sizeof(*e);
1058 for (i = 0; i < ia_pd_entries; i++) {
1059 if (e[i].t1 < l_t1)
1060 l_t1 = e[i].t1;
1061
1062 if (e[i].t2 < l_t2)
1063 l_t2 = e[i].t2;
1064
1065 if (e[i].valid > l_t3)
1066 l_t3 = e[i].valid;
1067 }
1068
1069 if (ia_pd_entries || ia_na_entries) {
1070 t1 = l_t1;
1071 t2 = l_t2;
1072 t3 = l_t3;
1073 }
1074
1075 return (int)(ia_pd_entries + ia_na_entries);
1076 }
1077
1078
1079 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1080 const void *status_msg, const int len)
1081 {
1082 uint8_t buf[len + 3];
1083
1084 memset(buf, 0, sizeof(buf));
1085 if (len) {
1086 buf[0] = '(';
1087 memcpy(&buf[1], status_msg, len);
1088 buf[len + 1] = ')';
1089 }
1090
1091 syslog(LOG_WARNING, "Server returned %s status %i %s",
1092 scope, code, buf);
1093 }
1094
1095
1096 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1097 const uint16_t code, const void *status_msg, const int len,
1098 int *ret)
1099 {
1100 dhcpv6_log_status_code(code, "message", status_msg, len);
1101
1102 switch (code) {
1103 case DHCPV6_UnspecFail:
1104 // Generic failure
1105 *ret = 0;
1106 break;
1107
1108 case DHCPV6_UseMulticast:
1109 // TODO handle multicast status code
1110 break;
1111
1112 case DHCPV6_NoAddrsAvail:
1113 case DHCPV6_NoPrefixAvail:
1114 if (orig == DHCPV6_MSG_REQUEST)
1115 *ret = 0; // Failure
1116 break;
1117
1118 default:
1119 break;
1120 }
1121 }
1122
1123
1124 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1125 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1126 const void *status_msg, const int len,
1127 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1128 {
1129 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1130 "IA_NA" : "IA_PD", status_msg, len);
1131
1132 switch (code) {
1133 case DHCPV6_NoBinding:
1134 switch (orig) {
1135 case DHCPV6_MSG_RENEW:
1136 case DHCPV6_MSG_REBIND:
1137 if ((*ret > 0) && !handled_status_codes[code])
1138 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1139 break;
1140
1141 default:
1142 break;
1143 }
1144 break;
1145
1146 case DHCPV6_NoAddrsAvail:
1147 case DHCPV6_NoPrefixAvail:
1148 switch (orig) {
1149 case DHCPV6_MSG_REQUEST:
1150 if (*ret != 0)
1151 *ret = 0;
1152 break;
1153 default:
1154 break;
1155 }
1156 break;
1157
1158 case DHCPV6_NotOnLink:
1159 // TODO handle not onlink in case of confirm
1160 break;
1161
1162 default:
1163 break;
1164 }
1165 }
Openwrt DHCPv6 Client