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01bda16b0b8b0f9d27612ba1070205b7af12db2d
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 */
15
16 #include <time.h>
17 #include <fcntl.h>
18 #include <errno.h>
19 #include <inttypes.h>
20 #include <stdlib.h>
21 #include <signal.h>
22 #include <limits.h>
23 #include <resolv.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <syslog.h>
27 #include <stdbool.h>
28 #include <ctype.h>
29 #include <sys/time.h>
30 #include <sys/ioctl.h>
31 #include <sys/socket.h>
32 #include <arpa/inet.h>
33 #include <netinet/in.h>
34
35 #include <net/if.h>
36 #include <net/ethernet.h>
37
38 #include "odhcp6c.h"
39 #ifdef USE_LIBUBOX
40 #include <libubox/md5.h>
41 #else
42 #include "md5.h"
43 #endif
44
45
46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
47 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
48 #define DHCPV6_CLIENT_PORT 546
49 #define DHCPV6_SERVER_PORT 547
50 #define DHCPV6_DUID_LLADDR 3
51 #define DHCPV6_REQ_DELAY 1
52
53 #define DHCPV6_SOL_MAX_RT_MIN 60
54 #define DHCPV6_SOL_MAX_RT_MAX 86400
55 #define DHCPV6_INF_MAX_RT_MIN 60
56 #define DHCPV6_INF_MAX_RT_MAX 86400
57
58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
59 const uint8_t transaction[3], enum dhcpv6_msg type,
60 const struct in6_addr *daddr);
61
62 static unsigned int dhcpv6_parse_ia(void *opt, void *end);
63
64 static unsigned int dhcpv6_calc_refresh_timers(void);
65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
66 const uint16_t code, const void *status_msg, const int len,
67 int *ret);
68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
69 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
70 const void *status_msg, const int len,
71 bool handled_status_codes[_DHCPV6_Status_Max],
72 int *ret);
73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
74 static void dhcpv6_clear_all_server_cand(void);
75
76 static reply_handler dhcpv6_handle_reply;
77 static reply_handler dhcpv6_handle_advert;
78 static reply_handler dhcpv6_handle_rebind_reply;
79 static reply_handler dhcpv6_handle_reconfigure;
80 static int dhcpv6_commit_advert(void);
81
82 // RFC 3315 - 5.5 Timeout and Delay values
83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
84 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
85 dhcpv6_handle_reconfigure, NULL},
86 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
87 dhcpv6_handle_advert, dhcpv6_commit_advert},
88 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
89 dhcpv6_handle_reply, NULL},
90 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
91 dhcpv6_handle_reply, NULL},
92 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
93 dhcpv6_handle_rebind_reply, NULL},
94 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
95 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
96 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
97 dhcpv6_handle_reply, NULL},
98 };
99
100 // Sockets
101 static int sock = -1;
102 static int ifindex = -1;
103 static int64_t t1 = 0, t2 = 0, t3 = 0;
104
105 // IA states
106 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
107 static bool stateful_only_mode = false;
108 static bool accept_reconfig = false;
109 // Server unicast address
110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
111
112 // Reconfigure key
113 static uint8_t reconf_key[16];
114
115 // client options
116 static unsigned int client_options = 0;
117
118 static uint32_t ntohl_unaligned(const uint8_t *data)
119 {
120 uint32_t buf;
121
122 memcpy(&buf, data, sizeof(buf));
123 return ntohl(buf);
124 }
125
126 static char *dhcpv6_msg_to_str(enum dhcpv6_msg msg)
127 {
128 switch (msg) {
129 case DHCPV6_MSG_SOLICIT:
130 return "SOLICIT";
131
132 case DHCPV6_MSG_ADVERT:
133 return "ADVERTISE";
134
135 case DHCPV6_MSG_REQUEST:
136 return "REQUEST";
137
138 case DHCPV6_MSG_RENEW:
139 return "RENEW";
140
141 case DHCPV6_MSG_REBIND:
142 return "REBIND";
143
144 case DHCPV6_MSG_REPLY:
145 return "REPLY";
146
147 case DHCPV6_MSG_RELEASE:
148 return "RELEASE";
149
150 case DHCPV6_MSG_DECLINE:
151 return "DECLINE";
152
153 case DHCPV6_MSG_RECONF:
154 return "RECONFIGURE";
155
156 case DHCPV6_MSG_INFO_REQ:
157 return "INFORMATION REQUEST";
158
159 default:
160 break;
161 }
162
163 return "UNKNOWN";
164 }
165
166 static char *dhcpv6_status_code_to_str(uint16_t code)
167 {
168 switch (code) {
169 case DHCPV6_Success:
170 return "Success";
171
172 case DHCPV6_UnspecFail:
173 return "Unspecified Failure";
174
175 case DHCPV6_NoAddrsAvail:
176 return "No Address Available";
177
178 case DHCPV6_NoBinding:
179 return "No Binding";
180
181 case DHCPV6_NotOnLink:
182 return "Not On Link";
183
184 case DHCPV6_UseMulticast:
185 return "Use Multicast";
186
187 case DHCPV6_NoPrefixAvail:
188 return "No Prefix Available";
189
190 default:
191 break;
192 }
193
194 return "Unknown";
195 }
196
197 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
198 {
199 client_options = options;
200 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
201
202 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
203 if (sock < 0)
204 goto failure;
205
206 // Detect interface
207 struct ifreq ifr;
208 memset(&ifr, 0, sizeof(ifr));
209 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
210 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
211 goto failure;
212
213 ifindex = ifr.ifr_ifindex;
214
215 // Create client DUID
216 size_t client_id_len;
217 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
218 if (client_id_len == 0) {
219 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
220 DHCPV6_DUID_LLADDR, 0, 1};
221
222 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
223 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
224
225 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
226 struct ifreq ifs[100], *ifp, *ifend;
227 struct ifconf ifc;
228 ifc.ifc_req = ifs;
229 ifc.ifc_len = sizeof(ifs);
230
231 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
232 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
233 // If our interface doesn't have an address...
234 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
235 for (ifp = ifc.ifc_req; ifp < ifend &&
236 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
237 memcpy(ifr.ifr_name, ifp->ifr_name,
238 sizeof(ifr.ifr_name));
239 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
240 continue;
241
242 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
243 ETHER_ADDR_LEN);
244 }
245 }
246
247 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
248 }
249
250 // Create ORO
251 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
252 uint16_t oro[] = {
253 htons(DHCPV6_OPT_SIP_SERVER_D),
254 htons(DHCPV6_OPT_SIP_SERVER_A),
255 htons(DHCPV6_OPT_DNS_SERVERS),
256 htons(DHCPV6_OPT_DNS_DOMAIN),
257 htons(DHCPV6_OPT_SNTP_SERVERS),
258 htons(DHCPV6_OPT_NTP_SERVER),
259 htons(DHCPV6_OPT_AFTR_NAME),
260 htons(DHCPV6_OPT_PD_EXCLUDE),
261 #ifdef EXT_CER_ID
262 htons(DHCPV6_OPT_CER_ID),
263 #endif
264 htons(DHCPV6_OPT_S46_CONT_MAPE),
265 htons(DHCPV6_OPT_S46_CONT_MAPT),
266 htons(DHCPV6_OPT_S46_CONT_LW),
267 };
268 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
269 }
270 // Required oro
271 uint16_t req_oro[] = {
272 htons(DHCPV6_OPT_INF_MAX_RT),
273 htons(DHCPV6_OPT_SOL_MAX_RT),
274 htons(DHCPV6_OPT_INFO_REFRESH),
275 };
276 odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro));
277
278 // Configure IPv6-options
279 int val = 1;
280 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
281 goto failure;
282
283 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
284 goto failure;
285
286 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
287 goto failure;
288
289 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
290 goto failure;
291
292 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
293 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
294
295 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
296 goto failure;
297
298 return 0;
299
300 failure:
301 if (sock >= 0)
302 close(sock);
303
304 return -1;
305 }
306
307 enum {
308 IOV_HDR=0,
309 IOV_ORO,
310 IOV_CL_ID,
311 IOV_SRV_ID,
312 IOV_OPTS,
313 IOV_RECONF_ACCEPT,
314 IOV_FQDN,
315 IOV_HDR_IA_NA,
316 IOV_IA_NA,
317 IOV_IA_PD,
318 IOV_TOTAL
319 };
320
321 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd, bool stateful_only)
322 {
323 int mode = DHCPV6_UNKNOWN;
324
325 na_mode = na;
326 pd_mode = pd;
327 stateful_only_mode = stateful_only;
328
329 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
330 mode = DHCPV6_STATELESS;
331 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
332 mode = DHCPV6_STATEFUL;
333
334 return mode;
335 }
336
337 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
338 {
339 // Build FQDN
340 char fqdn_buf[256];
341 gethostname(fqdn_buf, sizeof(fqdn_buf));
342 struct {
343 uint16_t type;
344 uint16_t len;
345 uint8_t flags;
346 uint8_t data[256];
347 } fqdn;
348 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
349 sizeof(fqdn.data), NULL, NULL);
350 fqdn.type = htons(DHCPV6_OPT_FQDN);
351 fqdn.len = htons(fqdn_len - 4);
352 fqdn.flags = 0;
353
354 // Build Client ID
355 size_t cl_id_len;
356 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
357
358 // Get Server ID
359 size_t srv_id_len;
360 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
361
362 // Build IA_PDs
363 size_t ia_pd_entries = 0, ia_pd_len = 0;
364 uint8_t *ia_pd;
365
366 if (type == DHCPV6_MSG_SOLICIT) {
367 odhcp6c_clear_state(STATE_IA_PD);
368 size_t n_prefixes;
369 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
370 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
371
372 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
373
374 for (size_t i = 0; i < n_prefixes; i++) {
375 struct dhcpv6_ia_hdr hdr_ia_pd = {
376 htons(DHCPV6_OPT_IA_PD),
377 htons(sizeof(hdr_ia_pd) - 4 +
378 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
379 request_prefixes[i].iaid, 0, 0
380 };
381 struct dhcpv6_ia_prefix pref = {
382 .type = htons(DHCPV6_OPT_IA_PREFIX),
383 .len = htons(sizeof(pref) - 4),
384 .prefix = request_prefixes[i].length
385 };
386 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
387 ia_pd_len += sizeof(hdr_ia_pd);
388 if (request_prefixes[i].length) {
389 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
390 ia_pd_len += sizeof(pref);
391 }
392 }
393 } else {
394 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
395 ia_pd_entries /= sizeof(*e);
396
397 // we're too lazy to count our distinct IAIDs,
398 // so just allocate maximally needed space
399 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
400 sizeof(struct dhcpv6_ia_hdr)));
401
402 for (size_t i = 0; i < ia_pd_entries; ++i) {
403 uint32_t iaid = e[i].iaid;
404
405 // check if this is an unprocessed IAID and skip if not.
406 int new_iaid = 1;
407 for (int j = i-1; j >= 0; j--) {
408 if (e[j].iaid == iaid) {
409 new_iaid = 0;
410 break;
411 }
412 }
413
414 if (!new_iaid)
415 continue;
416
417 // construct header
418 struct dhcpv6_ia_hdr hdr_ia_pd = {
419 htons(DHCPV6_OPT_IA_PD),
420 htons(sizeof(hdr_ia_pd) - 4),
421 iaid, 0, 0
422 };
423
424 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
425 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
426 ia_pd_len += sizeof(hdr_ia_pd);
427
428 for (size_t j = i; j < ia_pd_entries; j++) {
429 if (e[j].iaid != iaid)
430 continue;
431
432 uint8_t ex_len = 0;
433 if (e[j].priority > 0)
434 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
435
436 struct dhcpv6_ia_prefix p = {
437 .type = htons(DHCPV6_OPT_IA_PREFIX),
438 .len = htons(sizeof(p) - 4U + ex_len),
439 .prefix = e[j].length,
440 .addr = e[j].target
441 };
442
443 if (type == DHCPV6_MSG_REQUEST) {
444 p.preferred = htonl(e[j].preferred);
445 p.valid = htonl(e[j].valid);
446 }
447
448 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
449 ia_pd_len += sizeof(p);
450
451 if (ex_len) {
452 ia_pd[ia_pd_len++] = 0;
453 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
454 ia_pd[ia_pd_len++] = 0;
455 ia_pd[ia_pd_len++] = ex_len - 4;
456 ia_pd[ia_pd_len++] = e[j].priority;
457
458 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
459 excl >>= (64 - e[j].priority);
460 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
461
462 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
463 ia_pd[ia_pd_len + i] = excl & 0xff;
464 ia_pd_len += ex_len - 5;
465 }
466
467 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
468 }
469 }
470 }
471
472 // Build IA_NAs
473 size_t ia_na_entries, ia_na_len = 0;
474 void *ia_na = NULL;
475 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
476 ia_na_entries /= sizeof(*e);
477
478 struct dhcpv6_ia_hdr hdr_ia_na = {
479 htons(DHCPV6_OPT_IA_NA),
480 htons(sizeof(hdr_ia_na) - 4),
481 htonl(1), 0, 0
482 };
483
484 struct dhcpv6_ia_addr pa[ia_na_entries];
485 for (size_t i = 0; i < ia_na_entries; ++i) {
486 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
487 pa[i].len = htons(sizeof(pa[i]) - 4U);
488 pa[i].addr = e[i].target;
489
490 if (type == DHCPV6_MSG_REQUEST) {
491 pa[i].preferred = htonl(e[i].preferred);
492 pa[i].valid = htonl(e[i].valid);
493 } else {
494 pa[i].preferred = 0;
495 pa[i].valid = 0;
496 }
497 }
498
499 ia_na = pa;
500 ia_na_len = sizeof(pa);
501 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
502
503 // Reconfigure Accept
504 struct {
505 uint16_t type;
506 uint16_t length;
507 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
508
509 // Option list
510 size_t opts_len;
511 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
512
513 // Option Request List
514 size_t oro_entries, oro_len = 0;
515 uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries);
516
517 oro_entries /= sizeof(*s_oro);
518 oro = alloca(oro_entries * sizeof(*oro));
519
520 for (size_t i = 0; i < oro_entries; i++) {
521 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i]));
522
523 if (opt) {
524 if (!(opt->flags & OPT_ORO))
525 continue;
526
527 if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT)
528 continue;
529
530 if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ)
531 continue;
532
533 if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ)
534 continue;
535 }
536
537 oro[oro_len++] = s_oro[i];
538 }
539 oro_len *= sizeof(*oro);
540
541 // Prepare Header
542 struct {
543 uint8_t type;
544 uint8_t trid[3];
545 uint16_t elapsed_type;
546 uint16_t elapsed_len;
547 uint16_t elapsed_value;
548 uint16_t oro_type;
549 uint16_t oro_len;
550 } hdr = {
551 type, {trid[0], trid[1], trid[2]},
552 htons(DHCPV6_OPT_ELAPSED), htons(2),
553 htons((ecs > 0xffff) ? 0xffff : ecs),
554 htons(DHCPV6_OPT_ORO), htons(oro_len),
555 };
556
557 struct iovec iov[IOV_TOTAL] = {
558 [IOV_HDR] = {&hdr, sizeof(hdr)},
559 [IOV_ORO] = {oro, oro_len},
560 [IOV_CL_ID] = {cl_id, cl_id_len},
561 [IOV_SRV_ID] = {srv_id, srv_id_len},
562 [IOV_OPTS] = { opts, opts_len },
563 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
564 [IOV_FQDN] = {&fqdn, fqdn_len},
565 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
566 [IOV_IA_NA] = {ia_na, ia_na_len},
567 [IOV_IA_PD] = {ia_pd, ia_pd_len},
568 };
569
570 size_t cnt = IOV_TOTAL;
571 if (type == DHCPV6_MSG_INFO_REQ)
572 cnt = IOV_HDR_IA_NA;
573
574 // Disable IAs if not used
575 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
576 iov[IOV_HDR_IA_NA].iov_len = 0;
577
578 if (na_mode == IA_MODE_NONE)
579 iov[IOV_HDR_IA_NA].iov_len = 0;
580
581 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
582 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
583 iov[IOV_RECONF_ACCEPT].iov_len = 0;
584
585 if (!(client_options & DHCPV6_CLIENT_FQDN))
586 iov[IOV_FQDN].iov_len = 0;
587
588 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
589 0, ALL_DHCPV6_RELAYS, ifindex};
590 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
591 .msg_iov = iov, .msg_iovlen = cnt};
592
593 switch (type) {
594 case DHCPV6_MSG_REQUEST:
595 case DHCPV6_MSG_RENEW:
596 case DHCPV6_MSG_RELEASE:
597 case DHCPV6_MSG_DECLINE:
598 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
599 odhcp6c_addr_in_scope(&server_addr)) {
600 srv.sin6_addr = server_addr;
601 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
602 srv.sin6_scope_id = 0;
603 }
604 break;
605 default:
606 break;
607 }
608
609 if (sendmsg(sock, &msg, 0) < 0) {
610 char in6_str[INET6_ADDRSTRLEN];
611
612 syslog(LOG_ERR, "Failed to send %s message to %s (%s)",
613 dhcpv6_msg_to_str(type),
614 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
615 in6_str, sizeof(in6_str)), strerror(errno));
616 }
617 }
618
619 static int64_t dhcpv6_rand_delay(int64_t time)
620 {
621 int random;
622 odhcp6c_random(&random, sizeof(random));
623
624 return (time * ((int64_t)random % 1000LL)) / 10000LL;
625 }
626
627 int dhcpv6_request(enum dhcpv6_msg type)
628 {
629 uint8_t rc = 0;
630 uint64_t timeout = UINT32_MAX;
631 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
632
633 if (retx->delay) {
634 struct timespec ts = {0, 0};
635 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
636
637 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
638 }
639
640 if (type == DHCPV6_MSG_UNKNOWN)
641 timeout = t1;
642 else if (type == DHCPV6_MSG_RENEW)
643 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
644 else if (type == DHCPV6_MSG_REBIND)
645 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
646
647 if (timeout == 0)
648 return -1;
649
650 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
651 retx->name, timeout, retx->max_rc);
652
653 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
654
655 // Generate transaction ID
656 uint8_t trid[3] = {0, 0, 0};
657 if (type != DHCPV6_MSG_UNKNOWN)
658 odhcp6c_random(trid, sizeof(trid));
659
660 ssize_t len = -1;
661 int64_t rto = 0;
662
663 do {
664 if (rto == 0) {
665 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
666
667 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
668 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
669 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
670
671 rto = (retx->init_timeo * 1000 + delay);
672 } else
673 rto = (2 * rto + dhcpv6_rand_delay(rto));
674
675 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
676 rto = retx->max_timeo * 1000 +
677 dhcpv6_rand_delay(retx->max_timeo * 1000);
678
679 // Calculate end for this round and elapsed time
680 uint64_t round_end = round_start + rto;
681 elapsed = round_start - start;
682
683 // Don't wait too long if timeout differs from infinite
684 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
685 round_end = timeout * 1000 + start;
686
687 // Built and send package
688 switch (type) {
689 case DHCPV6_MSG_UNKNOWN:
690 break;
691 default:
692 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
693 retx->name, elapsed, rc);
694 // Fall through
695 case DHCPV6_MSG_SOLICIT:
696 case DHCPV6_MSG_INFO_REQ:
697 dhcpv6_send(type, trid, elapsed / 10);
698 rc++;
699 }
700
701 // Receive rounds
702 for (; len < 0 && (round_start < round_end);
703 round_start = odhcp6c_get_milli_time()) {
704 uint8_t buf[1536];
705 union {
706 struct cmsghdr hdr;
707 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
708 } cmsg_buf;
709 struct iovec iov = {buf, sizeof(buf)};
710 struct sockaddr_in6 addr;
711 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
712 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
713 .msg_controllen = sizeof(cmsg_buf)};
714 struct in6_pktinfo *pktinfo = NULL;
715 const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf;
716
717 // Check for pending signal
718 if (odhcp6c_signal_process())
719 return -1;
720
721 // Set timeout for receiving
722 uint64_t t = round_end - round_start;
723 struct timeval tv = {t / 1000, (t % 1000) * 1000};
724 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
725 &tv, sizeof(tv)) < 0)
726 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
727 strerror(errno));
728
729 // Receive cycle
730 len = recvmsg(sock, &msg, 0);
731 if (len < 0)
732 continue;
733
734 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
735 ch = CMSG_NXTHDR(&msg, ch)) {
736 if (ch->cmsg_level == SOL_IPV6 &&
737 ch->cmsg_type == IPV6_PKTINFO) {
738 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
739 break;
740 }
741 }
742
743 if (pktinfo == NULL) {
744 len = -1;
745 continue;
746 }
747
748 if (!dhcpv6_response_is_valid(buf, len, trid,
749 type, &pktinfo->ipi6_addr)) {
750 len = -1;
751 continue;
752 }
753
754 uint8_t *opt = &buf[4];
755 uint8_t *opt_end = opt + len - 4;
756
757 round_start = odhcp6c_get_milli_time();
758 elapsed = round_start - start;
759 syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms",
760 dhcpv6_msg_to_str(hdr->msg_type), elapsed);
761
762 if (retx->handler_reply)
763 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
764
765 if (len > 0 && round_end - round_start > 1000)
766 round_end = 1000 + round_start;
767 }
768
769 // Allow
770 if (retx->handler_finish)
771 len = retx->handler_finish();
772 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
773 (!retx->max_rc || rc < retx->max_rc));
774 return len;
775 }
776
777 // Message validation checks according to RFC3315 chapter 15
778 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
779 const uint8_t transaction[3], enum dhcpv6_msg type,
780 const struct in6_addr *daddr)
781 {
782 const struct dhcpv6_header *rep = buf;
783 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
784 transaction, sizeof(rep->tr_id)))
785 return false; // Invalid reply
786
787 if (type == DHCPV6_MSG_SOLICIT) {
788 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
789 rep->msg_type != DHCPV6_MSG_REPLY)
790 return false;
791
792 } else if (type == DHCPV6_MSG_UNKNOWN) {
793 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
794 return false;
795
796 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
797 return false;
798
799 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
800 rcmsg = DHCPV6_MSG_UNKNOWN;
801 uint16_t otype, olen = UINT16_MAX;
802 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
803 ia_present = false, options_valid = true;
804
805 size_t client_id_len, server_id_len;
806 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
807 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
808
809 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
810 if (otype == DHCPV6_OPT_CLIENTID) {
811 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
812 &odata[-4], client_id, client_id_len);
813 } else if (otype == DHCPV6_OPT_SERVERID) {
814 if (server_id_len)
815 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
816 &odata[-4], server_id, server_id_len);
817 else
818 serverid_ok = true;
819 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
820 sizeof(struct dhcpv6_auth_reconfigure)) {
821 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
822 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
823 continue;
824
825 md5_ctx_t md5;
826 uint8_t serverhash[16], secretbytes[64];
827 uint32_t hash[4];
828 memcpy(serverhash, r->key, sizeof(serverhash));
829 memset(r->key, 0, sizeof(r->key));
830
831 memset(secretbytes, 0, sizeof(secretbytes));
832 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
833
834 for (size_t i = 0; i < sizeof(secretbytes); ++i)
835 secretbytes[i] ^= 0x36;
836
837 md5_begin(&md5);
838 md5_hash(secretbytes, sizeof(secretbytes), &md5);
839 md5_hash(buf, len, &md5);
840 md5_end(hash, &md5);
841
842 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
843 secretbytes[i] ^= 0x36;
844 secretbytes[i] ^= 0x5c;
845 }
846
847 md5_begin(&md5);
848 md5_hash(secretbytes, sizeof(secretbytes), &md5);
849 md5_hash(hash, 16, &md5);
850 md5_end(hash, &md5);
851
852 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
853 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
854 rcmsg = odata[0];
855 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
856 ia_present = true;
857 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
858 options_valid = false;
859 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
860 (otype == DHCPV6_OPT_PD_EXCLUDE))
861 // Options are not allowed on global level
862 options_valid = false;
863 }
864
865 if (!options_valid || ((odata + olen) > end))
866 return false;
867
868 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
869 return false;
870
871 if (rep->msg_type == DHCPV6_MSG_RECONF) {
872 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
873 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
874 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
875 return false;
876 }
877
878 return clientid_ok && serverid_ok;
879 }
880
881 int dhcpv6_poll_reconfigure(void)
882 {
883 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
884
885 switch (ret) {
886 /*
887 * Only RENEW/REBIND/INFORMATION REQUEST
888 * message transmission can be requested
889 * by a RECONFIGURE
890 */
891 case DHCPV6_MSG_RENEW:
892 case DHCPV6_MSG_REBIND:
893 case DHCPV6_MSG_INFO_REQ:
894 ret = dhcpv6_request(ret);
895 break;
896
897 default:
898 break;
899 }
900
901 return ret;
902 }
903
904 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
905 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
906 {
907 uint16_t otype, olen;
908 uint8_t *odata;
909 enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN;
910
911 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
912 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
913 switch (odata[0]) {
914 case DHCPV6_MSG_REBIND:
915 if (t2 != UINT32_MAX)
916 t2 = 0;
917 // Fall through
918 case DHCPV6_MSG_RENEW:
919 if (t1 != UINT32_MAX)
920 t1 = 0;
921 // Fall through
922 case DHCPV6_MSG_INFO_REQ:
923 msg = odata[0];
924 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s",
925 dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF));
926 break;
927
928 default:
929 break;
930 }
931 }
932 }
933
934 if (msg != DHCPV6_MSG_UNKNOWN)
935 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
936
937 return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg);
938 }
939
940 // Collect all advertised servers
941 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
942 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
943 {
944 uint16_t olen, otype;
945 uint8_t *odata, pref = 0;
946 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
947 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
948 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
949 bool have_na = false;
950 int have_pd = 0;
951
952 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
953 if (orig == DHCPV6_MSG_SOLICIT &&
954 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
955 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
956 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
957 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
958 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
959 }
960
961 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
962 memcpy(cand.duid, odata, olen);
963 cand.duid_len = olen;
964 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
965 cand.preference >= 0) {
966 cand.preference = pref = odata[0];
967 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
968 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
969 cand.server_addr = *(struct in6_addr *)odata;
970
971 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
972 cand.wants_reconfigure = true;
973 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
974 uint32_t sol_max_rt = ntohl_unaligned(odata);
975 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
976 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
977 cand.sol_max_rt = sol_max_rt;
978
979 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
980 uint32_t inf_max_rt = ntohl_unaligned(odata);
981 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
982 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
983 cand.inf_max_rt = inf_max_rt;
984
985 } else if (otype == DHCPV6_OPT_IA_PD &&
986 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
987 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
988 uint8_t *oend = odata + olen, *d;
989 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
990 if (otype == DHCPV6_OPT_IA_PREFIX &&
991 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
992 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
993 have_pd = p->prefix;
994 }
995 }
996 } else if (otype == DHCPV6_OPT_IA_NA &&
997 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
998 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
999 uint8_t *oend = odata + olen, *d;
1000
1001 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
1002 if (otype == DHCPV6_OPT_IA_ADDR &&
1003 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
1004 have_na = true;
1005 }
1006 }
1007 }
1008
1009 if ((stateful_only_mode && !have_na && !have_pd) ||
1010 (!have_na && na_mode == IA_MODE_FORCE) ||
1011 (!have_pd && pd_mode == IA_MODE_FORCE)) {
1012 /*
1013 * RFC7083 states to process the SOL_MAX_RT and
1014 * INF_MAX_RT options even if the DHCPv6 server
1015 * did not propose any IA_NA and/or IA_PD
1016 */
1017 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
1018 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
1019 return -1;
1020 }
1021
1022 if (na_mode != IA_MODE_NONE && !have_na) {
1023 cand.has_noaddravail = true;
1024 cand.preference -= 1000;
1025 }
1026
1027 if (pd_mode != IA_MODE_NONE) {
1028 if (have_pd)
1029 cand.preference += 2000 + (128 - have_pd);
1030 else
1031 cand.preference -= 2000;
1032 }
1033
1034 if (cand.duid_len > 0) {
1035 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
1036 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
1037 dhcpv6_add_server_cand(&cand);
1038 }
1039
1040 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
1041 }
1042
1043 static int dhcpv6_commit_advert(void)
1044 {
1045 return dhcpv6_promote_server_cand();
1046 }
1047
1048 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
1049 const void *opt, const void *end, const struct sockaddr_in6 *from)
1050 {
1051 dhcpv6_handle_advert(orig, rc, opt, end, from);
1052 if (dhcpv6_commit_advert() < 0)
1053 return -1;
1054
1055 return dhcpv6_handle_reply(orig, rc, opt, end, from);
1056 }
1057
1058 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
1059 const void *opt, const void *end, const struct sockaddr_in6 *from)
1060 {
1061 uint8_t *odata;
1062 uint16_t otype, olen;
1063 uint32_t refresh = 86400;
1064 int ret = 1;
1065 unsigned int state_IAs;
1066 unsigned int updated_IAs = 0;
1067 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
1068
1069 odhcp6c_expire(true);
1070
1071 if (orig == DHCPV6_MSG_UNKNOWN) {
1072 static time_t last_update = 0;
1073 time_t now = odhcp6c_get_milli_time() / 1000;
1074
1075 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
1076 last_update = now;
1077
1078 if (t1 != UINT32_MAX)
1079 t1 -= elapsed;
1080
1081 if (t2 != UINT32_MAX)
1082 t2 -= elapsed;
1083
1084 if (t3 != UINT32_MAX)
1085 t3 -= elapsed;
1086
1087 if (t1 < 0)
1088 t1 = 0;
1089
1090 if (t2 < 0)
1091 t2 = 0;
1092
1093 if (t3 < 0)
1094 t3 = 0;
1095 }
1096
1097 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1098 // Delete NA and PD we have in the state from the Advert
1099 odhcp6c_clear_state(STATE_IA_NA);
1100 odhcp6c_clear_state(STATE_IA_PD);
1101 }
1102
1103 if (opt) {
1104 odhcp6c_clear_state(STATE_DNS);
1105 odhcp6c_clear_state(STATE_SEARCH);
1106 odhcp6c_clear_state(STATE_SNTP_IP);
1107 odhcp6c_clear_state(STATE_NTP_IP);
1108 odhcp6c_clear_state(STATE_NTP_FQDN);
1109 odhcp6c_clear_state(STATE_SIP_IP);
1110 odhcp6c_clear_state(STATE_SIP_FQDN);
1111 odhcp6c_clear_state(STATE_AFTR_NAME);
1112 odhcp6c_clear_state(STATE_CER);
1113 odhcp6c_clear_state(STATE_S46_MAPT);
1114 odhcp6c_clear_state(STATE_S46_MAPE);
1115 odhcp6c_clear_state(STATE_S46_LW);
1116 odhcp6c_clear_state(STATE_PASSTHRU);
1117 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1118
1119 // Parse and find all matching IAs
1120 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1121 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1122
1123 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1124 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1125 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1126
1127 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1128 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1129 continue;
1130
1131 // Test ID
1132 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1133 continue;
1134
1135 uint16_t code = DHCPV6_Success;
1136 uint16_t stype, slen;
1137 uint8_t *sdata;
1138 // Get and handle status code
1139 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1140 stype, slen, sdata) {
1141 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1142 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1143 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1144
1145 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1146
1147 if (code == DHCPV6_Success)
1148 continue;
1149
1150 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1151 code, mdata, mlen, handled_status_codes, &ret);
1152
1153 if (ret > 0)
1154 return ret;
1155
1156 break;
1157 }
1158 }
1159
1160 if (code != DHCPV6_Success)
1161 continue;
1162
1163 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1164 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1165 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1166 server_addr = *(struct in6_addr *)odata;
1167
1168 }
1169 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1170 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1171 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1172 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1173
1174 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1175 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1176 if (olen % 16 == 0)
1177 odhcp6c_add_state(STATE_DNS, odata, olen);
1178 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1179 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1180 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1181 if (olen % 16 == 0)
1182 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1183 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1184 uint16_t stype, slen;
1185 uint8_t *sdata;
1186 // Test status and bail if error
1187 dhcpv6_for_each_option(odata, odata + olen,
1188 stype, slen, sdata) {
1189 if (slen == 16 && (stype == NTP_MC_ADDR ||
1190 stype == NTP_SRV_ADDR))
1191 odhcp6c_add_state(STATE_NTP_IP,
1192 sdata, slen);
1193 else if (slen > 0 && stype == NTP_SRV_FQDN)
1194 odhcp6c_add_state(STATE_NTP_FQDN,
1195 sdata, slen);
1196 }
1197 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1198 if (olen == 16)
1199 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1200 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1201 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1202 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1203 refresh = ntohl_unaligned(odata);
1204 } else if (otype == DHCPV6_OPT_AUTH) {
1205 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1206 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1207 if (r->protocol == 3 && r->algorithm == 1 &&
1208 r->reconf_type == 1)
1209 memcpy(reconf_key, r->key, sizeof(r->key));
1210 }
1211 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1212 size_t cur_len;
1213 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1214 if (cur_len == 0)
1215 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1216 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1217 uint32_t sol_max_rt = ntohl_unaligned(odata);
1218 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1219 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1220 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1221 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1222 uint32_t inf_max_rt = ntohl_unaligned(odata);
1223 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1224 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1225 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1226 #ifdef EXT_CER_ID
1227 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1228 sizeof(struct dhcpv6_cer_id)) {
1229 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1230 struct in6_addr any = IN6ADDR_ANY_INIT;
1231 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1232 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1233 #endif
1234 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1235 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1236 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1237 size_t mape_len;
1238 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1239 if (mape_len == 0)
1240 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1241 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1242 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1243 } else
1244 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1245
1246 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1247 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1248 }
1249 }
1250
1251 // Bail out if fatal status code was received
1252 if (ret <= 0)
1253 return ret;
1254
1255 switch (orig) {
1256 case DHCPV6_MSG_REQUEST:
1257 case DHCPV6_MSG_REBIND:
1258 case DHCPV6_MSG_RENEW:
1259 state_IAs = dhcpv6_calc_refresh_timers();
1260 // In case there're no state IA entries
1261 // keep sending request/renew/rebind messages
1262 if (state_IAs == 0) {
1263 ret = 0;
1264 break;
1265 }
1266
1267 if (orig == DHCPV6_MSG_REQUEST) {
1268 // All server candidates can be cleared if not yet bound
1269 if (!odhcp6c_is_bound())
1270 dhcpv6_clear_all_server_cand();
1271
1272 odhcp6c_clear_state(STATE_SERVER_ADDR);
1273 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1274 } else if (orig == DHCPV6_MSG_RENEW) {
1275 // Send further renews if T1 is not set and if
1276 // there're IAs which were not in the Reply message
1277 if (!t1 && state_IAs != updated_IAs) {
1278 if (updated_IAs)
1279 // Publish updates
1280 script_call("updated", 0, false);
1281
1282 /*
1283 * RFC8415 states following in §18.2.10.1 :
1284 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1285 * message, but as this likely indicates that the server that
1286 * responded does not support that IA type, sending immediately is
1287 * unlikely to produce a different result. Therefore, the client
1288 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1289 * wait for the normal retransmission time (as if the Reply message
1290 * had not been received). The client continues to use other
1291 * bindings for which the server did return information
1292 */
1293 ret = -1;
1294 }
1295 } else if (orig == DHCPV6_MSG_REBIND) {
1296 odhcp6c_clear_state(STATE_SERVER_ADDR);
1297 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1298
1299 // Send further rebinds if T1 and T2 is not set and if
1300 // there're IAs which were not in the Reply message
1301 if (!t1 && !t2 && state_IAs != updated_IAs) {
1302 if (updated_IAs)
1303 // Publish updates
1304 script_call("updated", 0, false);
1305
1306 /*
1307 * RFC8415 states following in §18.2.10.1 :
1308 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1309 * message, but as this likely indicates that the server that
1310 * responded does not support that IA type, sending immediately is
1311 * unlikely to produce a different result. Therefore, the client
1312 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1313 * wait for the normal retransmission time (as if the Reply message
1314 * had not been received). The client continues to use other
1315 * bindings for which the server did return information
1316 */
1317 ret = -1;
1318 }
1319 }
1320 break;
1321
1322 case DHCPV6_MSG_INFO_REQ:
1323 // All server candidates can be cleared if not yet bound
1324 if (!odhcp6c_is_bound())
1325 dhcpv6_clear_all_server_cand();
1326
1327 t1 = refresh;
1328 break;
1329
1330 default:
1331 break;
1332 }
1333
1334 return ret;
1335 }
1336
1337 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1338 {
1339 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1340 unsigned int updated_IAs = 0;
1341 uint32_t t1, t2;
1342 uint16_t otype, olen;
1343 uint8_t *odata;
1344 char buf[INET6_ADDRSTRLEN];
1345
1346 t1 = ntohl(ia_hdr->t1);
1347 t2 = ntohl(ia_hdr->t2);
1348
1349 if (t1 > t2 && t1 > 0 && t2 > 0)
1350 return 0;
1351
1352 syslog(LOG_INFO, "%s %04x T1 %d T2 %d", ntohs(ia_hdr->type) == DHCPV6_OPT_IA_PD ? "IA_PD" : "IA_NA", ntohl(ia_hdr->iaid), t1, t2);
1353
1354 // Update address IA
1355 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1356 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1357 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1358
1359 entry.iaid = ia_hdr->iaid;
1360
1361 if (otype == DHCPV6_OPT_IA_PREFIX) {
1362 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1363 if (olen + 4U < sizeof(*prefix))
1364 continue;
1365
1366 entry.valid = ntohl(prefix->valid);
1367 entry.preferred = ntohl(prefix->preferred);
1368
1369 if (entry.preferred > entry.valid)
1370 continue;
1371
1372 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1373 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1374 if (entry.t1 > entry.t2)
1375 entry.t1 = entry.t2;
1376
1377 entry.length = prefix->prefix;
1378 entry.target = prefix->addr;
1379 uint16_t stype, slen;
1380 uint8_t *sdata;
1381
1382 // Parse PD-exclude
1383 bool ok = true;
1384 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1385 odata + olen, stype, slen, sdata) {
1386 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1387 continue;
1388
1389 uint8_t elen = sdata[0];
1390 if (elen > 64)
1391 elen = 64;
1392
1393 if (entry.length < 32 || elen <= entry.length) {
1394 ok = false;
1395 continue;
1396 }
1397
1398 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1399 if (slen <= bytes) {
1400 ok = false;
1401 continue;
1402 }
1403
1404 uint32_t exclude = 0;
1405 do {
1406 exclude = exclude << 8 | sdata[bytes];
1407 } while (--bytes);
1408
1409 exclude >>= 8 - ((elen - entry.length) % 8);
1410 exclude <<= 64 - elen;
1411
1412 // Abusing router & priority fields for exclusion
1413 entry.router = entry.target;
1414 entry.router.s6_addr32[1] |= htonl(exclude);
1415 entry.priority = elen;
1416 }
1417
1418 if (ok) {
1419 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1420 updated_IAs++;
1421
1422 syslog(LOG_INFO, "%s/%d preferred %d valid %d",
1423 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1424 entry.length, entry.preferred , entry.valid);
1425 }
1426
1427 entry.priority = 0;
1428 memset(&entry.router, 0, sizeof(entry.router));
1429 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1430 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1431 if (olen + 4U < sizeof(*addr))
1432 continue;
1433
1434 entry.preferred = ntohl(addr->preferred);
1435 entry.valid = ntohl(addr->valid);
1436
1437 if (entry.preferred > entry.valid)
1438 continue;
1439
1440 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1441 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1442 if (entry.t1 > entry.t2)
1443 entry.t1 = entry.t2;
1444
1445 entry.length = 128;
1446 entry.target = addr->addr;
1447
1448 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1449 updated_IAs++;
1450
1451 syslog(LOG_INFO, "%s preferred %d valid %d",
1452 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1453 entry.preferred , entry.valid);
1454 }
1455 }
1456
1457 return updated_IAs;
1458 }
1459
1460 static unsigned int dhcpv6_calc_refresh_timers(void)
1461 {
1462 struct odhcp6c_entry *e;
1463 size_t ia_na_entries, ia_pd_entries, i;
1464 size_t invalid_entries = 0;
1465 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1466
1467 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1468 ia_na_entries /= sizeof(*e);
1469
1470 for (i = 0; i < ia_na_entries; i++) {
1471 /* Exclude invalid IA_NA entries */
1472 if (!e[i].valid) {
1473 invalid_entries++;
1474 continue;
1475 }
1476
1477 if (e[i].t1 < l_t1)
1478 l_t1 = e[i].t1;
1479
1480 if (e[i].t2 < l_t2)
1481 l_t2 = e[i].t2;
1482
1483 if (e[i].valid > l_t3)
1484 l_t3 = e[i].valid;
1485 }
1486
1487 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1488 ia_pd_entries /= sizeof(*e);
1489
1490 for (i = 0; i < ia_pd_entries; i++) {
1491 /* Exclude invalid IA_PD entries */
1492 if (!e[i].valid) {
1493 invalid_entries++;
1494 continue;
1495 }
1496
1497 if (e[i].t1 < l_t1)
1498 l_t1 = e[i].t1;
1499
1500 if (e[i].t2 < l_t2)
1501 l_t2 = e[i].t2;
1502
1503 if (e[i].valid > l_t3)
1504 l_t3 = e[i].valid;
1505 }
1506
1507 if (ia_pd_entries + ia_na_entries - invalid_entries) {
1508 t1 = l_t1;
1509 t2 = l_t2;
1510 t3 = l_t3;
1511
1512 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
1513 }
1514
1515 return (unsigned int)(ia_pd_entries + ia_na_entries);
1516 }
1517
1518 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1519 const void *status_msg, int len)
1520 {
1521 const char *src = status_msg;
1522 char buf[len + 3];
1523 char *dst = buf;
1524
1525 if (len) {
1526 *dst++ = '(';
1527 while (len--) {
1528 *dst = isprint((unsigned char)*src) ? *src : '?';
1529 src++;
1530 dst++;
1531 }
1532 *dst++ = ')';
1533 }
1534
1535 *dst = 0;
1536
1537 syslog(LOG_WARNING, "Server returned %s status '%s %s'",
1538 scope, dhcpv6_status_code_to_str(code), buf);
1539 }
1540
1541 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1542 const uint16_t code, const void *status_msg, const int len,
1543 int *ret)
1544 {
1545 dhcpv6_log_status_code(code, "message", status_msg, len);
1546
1547 switch (code) {
1548 case DHCPV6_UnspecFail:
1549 // Generic failure
1550 *ret = 0;
1551 break;
1552
1553 case DHCPV6_UseMulticast:
1554 switch(orig) {
1555 case DHCPV6_MSG_REQUEST:
1556 case DHCPV6_MSG_RENEW:
1557 case DHCPV6_MSG_RELEASE:
1558 case DHCPV6_MSG_DECLINE:
1559 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1560 server_addr = in6addr_any;
1561 *ret = 0;
1562 break;
1563 default:
1564 break;
1565 }
1566 break;
1567
1568 case DHCPV6_NoAddrsAvail:
1569 case DHCPV6_NoPrefixAvail:
1570 if (orig == DHCPV6_MSG_REQUEST)
1571 *ret = 0; // Failure
1572 break;
1573
1574 default:
1575 break;
1576 }
1577 }
1578
1579 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1580 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1581 const void *status_msg, const int len,
1582 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1583 {
1584 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1585 "IA_NA" : "IA_PD", status_msg, len);
1586
1587 switch (code) {
1588 case DHCPV6_NoBinding:
1589 switch (orig) {
1590 case DHCPV6_MSG_RENEW:
1591 case DHCPV6_MSG_REBIND:
1592 if ((*ret > 0) && !handled_status_codes[code])
1593 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1594 break;
1595
1596 default:
1597 break;
1598 }
1599 break;
1600
1601 default:
1602 *ret = 0;
1603 break;
1604 }
1605 }
1606
1607 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1608 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1609 {
1610 size_t cand_len, i;
1611 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1612
1613 // Remove identical duid server candidate
1614 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1615 if (cand->duid_len == c[i].duid_len &&
1616 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1617 free(c[i].ia_na);
1618 free(c[i].ia_pd);
1619 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1620 break;
1621 }
1622 }
1623
1624 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1625 i < cand_len / sizeof(*c); ++i) {
1626 if (c[i].preference < cand->preference)
1627 break;
1628 }
1629
1630 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1631 free(cand->ia_na);
1632 free(cand->ia_pd);
1633 }
1634 }
1635
1636 static void dhcpv6_clear_all_server_cand(void)
1637 {
1638 size_t cand_len, i;
1639 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1640
1641 // Server candidates need deep delete for IA_NA/IA_PD
1642 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1643 free(c[i].ia_na);
1644 free(c[i].ia_pd);
1645 }
1646 odhcp6c_clear_state(STATE_SERVER_CAND);
1647 }
1648
1649 int dhcpv6_promote_server_cand(void)
1650 {
1651 size_t cand_len;
1652 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1653 uint16_t hdr[2];
1654 int ret = DHCPV6_STATELESS;
1655
1656 // Clear lingering candidate state info
1657 odhcp6c_clear_state(STATE_SERVER_ID);
1658 odhcp6c_clear_state(STATE_IA_NA);
1659 odhcp6c_clear_state(STATE_IA_PD);
1660
1661 if (!cand_len)
1662 return -1;
1663
1664 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1665 na_mode = IA_MODE_NONE;
1666
1667 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1668 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1669
1670 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1671 }
1672
1673 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1674 hdr[1] = htons(cand->duid_len);
1675 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1676 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1677 accept_reconfig = cand->wants_reconfigure;
1678
1679 if (cand->ia_na_len) {
1680 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1681 free(cand->ia_na);
1682 if (na_mode != IA_MODE_NONE)
1683 ret = DHCPV6_STATEFUL;
1684 }
1685
1686 if (cand->ia_pd_len) {
1687 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1688 free(cand->ia_pd);
1689 if (pd_mode != IA_MODE_NONE)
1690 ret = DHCPV6_STATEFUL;
1691 }
1692
1693 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1694 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1695
1696 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1697
1698 return ret;
1699 }
Openwrt DHCPv6 Client