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