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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 static char *dhcpv6_msg_str[] = {
128 "UNKNOWN",
129 "SOLICIT",
130 "ADVERTISE",
131 "REQUEST",
132 "RENEW",
133 "REBIND",
134 "REPLY",
135 "DECLINE",
136 "RECONFIGURE",
137 "INFORMATION REQUEST",
138 };
139
140 if (msg < _DHCPV6_MSG_MAX)
141 return dhcpv6_msg_str[msg];
142
143 return "Unknown";
144 }
145
146 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
147 {
148 client_options = options;
149 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
150
151 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
152 if (sock < 0)
153 goto failure;
154
155 // Detect interface
156 struct ifreq ifr;
157 memset(&ifr, 0, sizeof(ifr));
158 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
159 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
160 goto failure;
161
162 ifindex = ifr.ifr_ifindex;
163
164 // Create client DUID
165 size_t client_id_len;
166 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
167 if (client_id_len == 0) {
168 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
169 DHCPV6_DUID_LLADDR, 0, 1};
170
171 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
172 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
173
174 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
175 struct ifreq ifs[100], *ifp, *ifend;
176 struct ifconf ifc;
177 ifc.ifc_req = ifs;
178 ifc.ifc_len = sizeof(ifs);
179
180 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
181 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
182 // If our interface doesn't have an address...
183 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
184 for (ifp = ifc.ifc_req; ifp < ifend &&
185 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
186 memcpy(ifr.ifr_name, ifp->ifr_name,
187 sizeof(ifr.ifr_name));
188 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
189 continue;
190
191 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
192 ETHER_ADDR_LEN);
193 }
194 }
195
196 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
197 }
198
199 // Create ORO
200 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
201 uint16_t oro[] = {
202 htons(DHCPV6_OPT_SIP_SERVER_D),
203 htons(DHCPV6_OPT_SIP_SERVER_A),
204 htons(DHCPV6_OPT_DNS_SERVERS),
205 htons(DHCPV6_OPT_DNS_DOMAIN),
206 htons(DHCPV6_OPT_SNTP_SERVERS),
207 htons(DHCPV6_OPT_NTP_SERVER),
208 htons(DHCPV6_OPT_AFTR_NAME),
209 htons(DHCPV6_OPT_PD_EXCLUDE),
210 #ifdef EXT_CER_ID
211 htons(DHCPV6_OPT_CER_ID),
212 #endif
213 htons(DHCPV6_OPT_S46_CONT_MAPE),
214 htons(DHCPV6_OPT_S46_CONT_MAPT),
215 htons(DHCPV6_OPT_S46_CONT_LW),
216 };
217 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
218 }
219 // Required oro
220 uint16_t req_oro[] = {
221 htons(DHCPV6_OPT_INF_MAX_RT),
222 htons(DHCPV6_OPT_SOL_MAX_RT),
223 htons(DHCPV6_OPT_INFO_REFRESH),
224 };
225 odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro));
226
227 // Configure IPv6-options
228 int val = 1;
229 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
230 goto failure;
231
232 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
233 goto failure;
234
235 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
236 goto failure;
237
238 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
239 goto failure;
240
241 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
242 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
243
244 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
245 goto failure;
246
247 return 0;
248
249 failure:
250 if (sock >= 0)
251 close(sock);
252
253 return -1;
254 }
255
256 enum {
257 IOV_HDR=0,
258 IOV_ORO,
259 IOV_CL_ID,
260 IOV_SRV_ID,
261 IOV_OPTS,
262 IOV_RECONF_ACCEPT,
263 IOV_FQDN,
264 IOV_HDR_IA_NA,
265 IOV_IA_NA,
266 IOV_IA_PD,
267 IOV_TOTAL
268 };
269
270 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
271 {
272 int mode = DHCPV6_UNKNOWN;
273
274 na_mode = na;
275 pd_mode = pd;
276
277 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
278 mode = DHCPV6_STATELESS;
279 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
280 mode = DHCPV6_STATEFUL;
281
282 return mode;
283 }
284
285 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
286 {
287 // Build FQDN
288 char fqdn_buf[256];
289 gethostname(fqdn_buf, sizeof(fqdn_buf));
290 struct {
291 uint16_t type;
292 uint16_t len;
293 uint8_t flags;
294 uint8_t data[256];
295 } fqdn;
296 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
297 sizeof(fqdn.data), NULL, NULL);
298 fqdn.type = htons(DHCPV6_OPT_FQDN);
299 fqdn.len = htons(fqdn_len - 4);
300 fqdn.flags = 0;
301
302 // Build Client ID
303 size_t cl_id_len;
304 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
305
306 // Get Server ID
307 size_t srv_id_len;
308 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
309
310 // Build IA_PDs
311 size_t ia_pd_entries = 0, ia_pd_len = 0;
312 uint8_t *ia_pd;
313
314 if (type == DHCPV6_MSG_SOLICIT) {
315 odhcp6c_clear_state(STATE_IA_PD);
316 size_t n_prefixes;
317 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
318 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
319
320 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
321
322 for (size_t i = 0; i < n_prefixes; i++) {
323 struct dhcpv6_ia_hdr hdr_ia_pd = {
324 htons(DHCPV6_OPT_IA_PD),
325 htons(sizeof(hdr_ia_pd) - 4 +
326 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
327 request_prefixes[i].iaid, 0, 0
328 };
329 struct dhcpv6_ia_prefix pref = {
330 .type = htons(DHCPV6_OPT_IA_PREFIX),
331 .len = htons(sizeof(pref) - 4),
332 .prefix = request_prefixes[i].length
333 };
334 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
335 ia_pd_len += sizeof(hdr_ia_pd);
336 if (request_prefixes[i].length) {
337 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
338 ia_pd_len += sizeof(pref);
339 }
340 }
341 } else {
342 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
343 ia_pd_entries /= sizeof(*e);
344
345 // we're too lazy to count our distinct IAIDs,
346 // so just allocate maximally needed space
347 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
348 sizeof(struct dhcpv6_ia_hdr)));
349
350 for (size_t i = 0; i < ia_pd_entries; ++i) {
351 uint32_t iaid = e[i].iaid;
352
353 // check if this is an unprocessed IAID and skip if not.
354 int new_iaid = 1;
355 for (int j = i-1; j >= 0; j--) {
356 if (e[j].iaid == iaid) {
357 new_iaid = 0;
358 break;
359 }
360 }
361
362 if (!new_iaid)
363 continue;
364
365 // construct header
366 struct dhcpv6_ia_hdr hdr_ia_pd = {
367 htons(DHCPV6_OPT_IA_PD),
368 htons(sizeof(hdr_ia_pd) - 4),
369 iaid, 0, 0
370 };
371
372 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
373 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
374 ia_pd_len += sizeof(hdr_ia_pd);
375
376 for (size_t j = i; j < ia_pd_entries; j++) {
377 if (e[j].iaid != iaid)
378 continue;
379
380 uint8_t ex_len = 0;
381 if (e[j].priority > 0)
382 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
383
384 struct dhcpv6_ia_prefix p = {
385 .type = htons(DHCPV6_OPT_IA_PREFIX),
386 .len = htons(sizeof(p) - 4U + ex_len),
387 .prefix = e[j].length,
388 .addr = e[j].target
389 };
390
391 if (type == DHCPV6_MSG_REQUEST) {
392 p.preferred = htonl(e[j].preferred);
393 p.valid = htonl(e[j].valid);
394 }
395
396 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
397 ia_pd_len += sizeof(p);
398
399 if (ex_len) {
400 ia_pd[ia_pd_len++] = 0;
401 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
402 ia_pd[ia_pd_len++] = 0;
403 ia_pd[ia_pd_len++] = ex_len - 4;
404 ia_pd[ia_pd_len++] = e[j].priority;
405
406 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
407 excl >>= (64 - e[j].priority);
408 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
409
410 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
411 ia_pd[ia_pd_len + i] = excl & 0xff;
412 ia_pd_len += ex_len - 5;
413 }
414
415 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
416 }
417 }
418 }
419
420 // Build IA_NAs
421 size_t ia_na_entries, ia_na_len = 0;
422 void *ia_na = NULL;
423 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
424 ia_na_entries /= sizeof(*e);
425
426 struct dhcpv6_ia_hdr hdr_ia_na = {
427 htons(DHCPV6_OPT_IA_NA),
428 htons(sizeof(hdr_ia_na) - 4),
429 htonl(1), 0, 0
430 };
431
432 struct dhcpv6_ia_addr pa[ia_na_entries];
433 for (size_t i = 0; i < ia_na_entries; ++i) {
434 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
435 pa[i].len = htons(sizeof(pa[i]) - 4U);
436 pa[i].addr = e[i].target;
437
438 if (type == DHCPV6_MSG_REQUEST) {
439 pa[i].preferred = htonl(e[i].preferred);
440 pa[i].valid = htonl(e[i].valid);
441 } else {
442 pa[i].preferred = 0;
443 pa[i].valid = 0;
444 }
445 }
446
447 ia_na = pa;
448 ia_na_len = sizeof(pa);
449 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
450
451 // Reconfigure Accept
452 struct {
453 uint16_t type;
454 uint16_t length;
455 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
456
457 // Option list
458 size_t opts_len;
459 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
460
461 // Option Request List
462 size_t oro_entries, oro_len = 0;
463 uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries);
464
465 oro_entries /= sizeof(*s_oro);
466 oro = alloca(oro_entries * sizeof(*oro));
467
468 for (size_t i = 0; i < oro_entries; i++) {
469 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i]));
470
471 if (opt) {
472 if (!(opt->flags & OPT_ORO))
473 continue;
474
475 if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT)
476 continue;
477
478 if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ)
479 continue;
480
481 if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ)
482 continue;
483 }
484
485 oro[oro_len++] = s_oro[i];
486 }
487 oro_len *= sizeof(*oro);
488
489 // Prepare Header
490 struct {
491 uint8_t type;
492 uint8_t trid[3];
493 uint16_t elapsed_type;
494 uint16_t elapsed_len;
495 uint16_t elapsed_value;
496 uint16_t oro_type;
497 uint16_t oro_len;
498 } hdr = {
499 type, {trid[0], trid[1], trid[2]},
500 htons(DHCPV6_OPT_ELAPSED), htons(2),
501 htons((ecs > 0xffff) ? 0xffff : ecs),
502 htons(DHCPV6_OPT_ORO), htons(oro_len),
503 };
504
505 struct iovec iov[IOV_TOTAL] = {
506 [IOV_HDR] = {&hdr, sizeof(hdr)},
507 [IOV_ORO] = {oro, oro_len},
508 [IOV_CL_ID] = {cl_id, cl_id_len},
509 [IOV_SRV_ID] = {srv_id, srv_id_len},
510 [IOV_OPTS] = { opts, opts_len },
511 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
512 [IOV_FQDN] = {&fqdn, fqdn_len},
513 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
514 [IOV_IA_NA] = {ia_na, ia_na_len},
515 [IOV_IA_PD] = {ia_pd, ia_pd_len},
516 };
517
518 size_t cnt = IOV_TOTAL;
519 if (type == DHCPV6_MSG_INFO_REQ)
520 cnt = IOV_HDR_IA_NA;
521
522 // Disable IAs if not used
523 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
524 iov[IOV_HDR_IA_NA].iov_len = 0;
525
526 if (na_mode == IA_MODE_NONE)
527 iov[IOV_HDR_IA_NA].iov_len = 0;
528
529 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
530 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
531 iov[IOV_RECONF_ACCEPT].iov_len = 0;
532
533 if (!(client_options & DHCPV6_CLIENT_FQDN))
534 iov[IOV_FQDN].iov_len = 0;
535
536 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
537 0, ALL_DHCPV6_RELAYS, ifindex};
538 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
539 .msg_iov = iov, .msg_iovlen = cnt};
540
541 switch (type) {
542 case DHCPV6_MSG_REQUEST:
543 case DHCPV6_MSG_RENEW:
544 case DHCPV6_MSG_RELEASE:
545 case DHCPV6_MSG_DECLINE:
546 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
547 odhcp6c_addr_in_scope(&server_addr)) {
548 srv.sin6_addr = server_addr;
549 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
550 srv.sin6_scope_id = 0;
551 }
552 break;
553 default:
554 break;
555 }
556
557 if (sendmsg(sock, &msg, 0) < 0) {
558 char in6_str[INET6_ADDRSTRLEN];
559
560 syslog(LOG_ERR, "Failed to send %s message to %s (%s)",
561 dhcpv6_msg_to_str(type),
562 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
563 in6_str, sizeof(in6_str)), strerror(errno));
564 }
565 }
566
567 static int64_t dhcpv6_rand_delay(int64_t time)
568 {
569 int random;
570 odhcp6c_random(&random, sizeof(random));
571
572 return (time * ((int64_t)random % 1000LL)) / 10000LL;
573 }
574
575 int dhcpv6_request(enum dhcpv6_msg type)
576 {
577 uint8_t rc = 0;
578 uint64_t timeout = UINT32_MAX;
579 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
580
581 if (retx->delay) {
582 struct timespec ts = {0, 0};
583 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
584
585 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
586 }
587
588 if (type == DHCPV6_MSG_UNKNOWN)
589 timeout = t1;
590 else if (type == DHCPV6_MSG_RENEW)
591 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
592 else if (type == DHCPV6_MSG_REBIND)
593 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
594
595 if (timeout == 0)
596 return -1;
597
598 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
599 retx->name, timeout, retx->max_rc);
600
601 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
602
603 // Generate transaction ID
604 uint8_t trid[3] = {0, 0, 0};
605 if (type != DHCPV6_MSG_UNKNOWN)
606 odhcp6c_random(trid, sizeof(trid));
607
608 ssize_t len = -1;
609 int64_t rto = 0;
610
611 do {
612 if (rto == 0) {
613 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
614
615 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
616 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
617 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
618
619 rto = (retx->init_timeo * 1000 + delay);
620 } else
621 rto = (2 * rto + dhcpv6_rand_delay(rto));
622
623 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
624 rto = retx->max_timeo * 1000 +
625 dhcpv6_rand_delay(retx->max_timeo * 1000);
626
627 // Calculate end for this round and elapsed time
628 uint64_t round_end = round_start + rto;
629 elapsed = round_start - start;
630
631 // Don't wait too long if timeout differs from infinite
632 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
633 round_end = timeout * 1000 + start;
634
635 // Built and send package
636 switch (type) {
637 case DHCPV6_MSG_UNKNOWN:
638 break;
639 default:
640 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
641 retx->name, elapsed, rc);
642 // Fall through
643 case DHCPV6_MSG_SOLICIT:
644 case DHCPV6_MSG_INFO_REQ:
645 dhcpv6_send(type, trid, elapsed / 10);
646 rc++;
647 }
648
649 // Receive rounds
650 for (; len < 0 && (round_start < round_end);
651 round_start = odhcp6c_get_milli_time()) {
652 uint8_t buf[1536];
653 union {
654 struct cmsghdr hdr;
655 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
656 } cmsg_buf;
657 struct iovec iov = {buf, sizeof(buf)};
658 struct sockaddr_in6 addr;
659 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
660 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
661 .msg_controllen = sizeof(cmsg_buf)};
662 struct in6_pktinfo *pktinfo = NULL;
663
664 // Check for pending signal
665 if (odhcp6c_signal_process())
666 return -1;
667
668 // Set timeout for receiving
669 uint64_t t = round_end - round_start;
670 struct timeval tv = {t / 1000, (t % 1000) * 1000};
671 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
672 &tv, sizeof(tv)) < 0)
673 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
674 strerror(errno));
675
676 // Receive cycle
677 len = recvmsg(sock, &msg, 0);
678 if (len < 0)
679 continue;
680
681 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
682 ch = CMSG_NXTHDR(&msg, ch)) {
683 if (ch->cmsg_level == SOL_IPV6 &&
684 ch->cmsg_type == IPV6_PKTINFO) {
685 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
686 break;
687 }
688 }
689
690 if (pktinfo == NULL) {
691 len = -1;
692 continue;
693 }
694
695 if (!dhcpv6_response_is_valid(buf, len, trid,
696 type, &pktinfo->ipi6_addr)) {
697 len = -1;
698 continue;
699 }
700
701 uint8_t *opt = &buf[4];
702 uint8_t *opt_end = opt + len - 4;
703
704 round_start = odhcp6c_get_milli_time();
705 elapsed = round_start - start;
706 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
707 elapsed);
708
709 if (retx->handler_reply)
710 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
711
712 if (len > 0 && round_end - round_start > 1000)
713 round_end = 1000 + round_start;
714 }
715
716 // Allow
717 if (retx->handler_finish)
718 len = retx->handler_finish();
719 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
720 (!retx->max_rc || rc < retx->max_rc));
721 return len;
722 }
723
724 // Message validation checks according to RFC3315 chapter 15
725 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
726 const uint8_t transaction[3], enum dhcpv6_msg type,
727 const struct in6_addr *daddr)
728 {
729 const struct dhcpv6_header *rep = buf;
730 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
731 transaction, sizeof(rep->tr_id)))
732 return false; // Invalid reply
733
734 if (type == DHCPV6_MSG_SOLICIT) {
735 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
736 rep->msg_type != DHCPV6_MSG_REPLY)
737 return false;
738
739 } else if (type == DHCPV6_MSG_UNKNOWN) {
740 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
741 return false;
742
743 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
744 return false;
745
746 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
747 rcmsg = DHCPV6_MSG_UNKNOWN;
748 uint16_t otype, olen = UINT16_MAX;
749 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
750 ia_present = false, options_valid = true;
751
752 size_t client_id_len, server_id_len;
753 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
754 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
755
756 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
757 if (otype == DHCPV6_OPT_CLIENTID) {
758 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
759 &odata[-4], client_id, client_id_len);
760 } else if (otype == DHCPV6_OPT_SERVERID) {
761 if (server_id_len)
762 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
763 &odata[-4], server_id, server_id_len);
764 else
765 serverid_ok = true;
766 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
767 sizeof(struct dhcpv6_auth_reconfigure)) {
768 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
769 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
770 continue;
771
772 md5_ctx_t md5;
773 uint8_t serverhash[16], secretbytes[64];
774 uint32_t hash[4];
775 memcpy(serverhash, r->key, sizeof(serverhash));
776 memset(r->key, 0, sizeof(r->key));
777
778 memset(secretbytes, 0, sizeof(secretbytes));
779 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
780
781 for (size_t i = 0; i < sizeof(secretbytes); ++i)
782 secretbytes[i] ^= 0x36;
783
784 md5_begin(&md5);
785 md5_hash(secretbytes, sizeof(secretbytes), &md5);
786 md5_hash(buf, len, &md5);
787 md5_end(hash, &md5);
788
789 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
790 secretbytes[i] ^= 0x36;
791 secretbytes[i] ^= 0x5c;
792 }
793
794 md5_begin(&md5);
795 md5_hash(secretbytes, sizeof(secretbytes), &md5);
796 md5_hash(hash, 16, &md5);
797 md5_end(hash, &md5);
798
799 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
800 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
801 rcmsg = odata[0];
802 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
803 ia_present = true;
804 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
805 options_valid = false;
806 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
807 (otype == DHCPV6_OPT_PD_EXCLUDE))
808 // Options are not allowed on global level
809 options_valid = false;
810 }
811
812 if (!options_valid || ((odata + olen) > end))
813 return false;
814
815 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
816 return false;
817
818 if (rep->msg_type == DHCPV6_MSG_RECONF) {
819 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
820 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
821 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
822 return false;
823 }
824
825 return clientid_ok && serverid_ok;
826 }
827
828 int dhcpv6_poll_reconfigure(void)
829 {
830 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
831
832 if (ret != -1)
833 ret = dhcpv6_request(ret);
834
835 return ret;
836 }
837
838 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
839 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
840 {
841 uint16_t otype, olen;
842 uint8_t *odata;
843 int msg = -1;
844
845 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
846 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
847 switch (odata[0]) {
848 case DHCPV6_MSG_REBIND:
849 if (t2 != UINT32_MAX)
850 t2 = 0;
851 // Fall through
852 case DHCPV6_MSG_RENEW:
853 if (t1 != UINT32_MAX)
854 t1 = 0;
855 // Fall through
856 case DHCPV6_MSG_INFO_REQ:
857 msg = odata[0];
858 syslog(LOG_NOTICE, "Got a %s (msg-type %s)",
859 dhcpv6_msg_to_str(otype),
860 dhcpv6_msg_to_str(msg));
861 break;
862
863 default:
864 break;
865 }
866 }
867 }
868
869 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
870
871 return msg;
872 }
873
874 // Collect all advertised servers
875 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
876 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
877 {
878 uint16_t olen, otype;
879 uint8_t *odata, pref = 0;
880 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
881 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
882 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
883 bool have_na = false;
884 int have_pd = 0;
885
886 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
887 if (orig == DHCPV6_MSG_SOLICIT &&
888 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
889 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
890 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
891 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
892 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
893 }
894
895 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
896 memcpy(cand.duid, odata, olen);
897 cand.duid_len = olen;
898 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
899 cand.preference >= 0) {
900 cand.preference = pref = odata[0];
901 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
902 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
903 cand.server_addr = *(struct in6_addr *)odata;
904
905 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
906 cand.wants_reconfigure = true;
907 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
908 uint32_t sol_max_rt = ntohl_unaligned(odata);
909 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
910 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
911 cand.sol_max_rt = sol_max_rt;
912
913 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
914 uint32_t inf_max_rt = ntohl_unaligned(odata);
915 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
916 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
917 cand.inf_max_rt = inf_max_rt;
918
919 } else if (otype == DHCPV6_OPT_IA_PD &&
920 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
921 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
922 uint8_t *oend = odata + olen, *d;
923 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
924 if (otype == DHCPV6_OPT_IA_PREFIX &&
925 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
926 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
927 have_pd = p->prefix;
928 }
929 }
930 } else if (otype == DHCPV6_OPT_IA_NA &&
931 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
932 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
933 uint8_t *oend = odata + olen, *d;
934
935 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
936 if (otype == DHCPV6_OPT_IA_ADDR &&
937 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
938 have_na = true;
939 }
940 }
941 }
942
943 if ((!have_na && na_mode == IA_MODE_FORCE) ||
944 (!have_pd && pd_mode == IA_MODE_FORCE)) {
945 /*
946 * RFC7083 states to process the SOL_MAX_RT and
947 * INF_MAX_RT options even if the DHCPv6 server
948 * did not propose any IA_NA and/or IA_PD
949 */
950 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
951 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
952 return -1;
953 }
954
955 if (na_mode != IA_MODE_NONE && !have_na) {
956 cand.has_noaddravail = true;
957 cand.preference -= 1000;
958 }
959
960 if (pd_mode != IA_MODE_NONE) {
961 if (have_pd)
962 cand.preference += 2000 + (128 - have_pd);
963 else
964 cand.preference -= 2000;
965 }
966
967 if (cand.duid_len > 0) {
968 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
969 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
970 dhcpv6_add_server_cand(&cand);
971 }
972
973 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
974 }
975
976 static int dhcpv6_commit_advert(void)
977 {
978 return dhcpv6_promote_server_cand();
979 }
980
981 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
982 const void *opt, const void *end, const struct sockaddr_in6 *from)
983 {
984 dhcpv6_handle_advert(orig, rc, opt, end, from);
985 if (dhcpv6_commit_advert() < 0)
986 return -1;
987
988 return dhcpv6_handle_reply(orig, rc, opt, end, from);
989 }
990
991 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
992 const void *opt, const void *end, const struct sockaddr_in6 *from)
993 {
994 uint8_t *odata;
995 uint16_t otype, olen;
996 uint32_t refresh = 86400;
997 int ret = 1;
998 unsigned int state_IAs;
999 unsigned int updated_IAs = 0;
1000 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
1001
1002 odhcp6c_expire();
1003
1004 if (orig == DHCPV6_MSG_UNKNOWN) {
1005 static time_t last_update = 0;
1006 time_t now = odhcp6c_get_milli_time() / 1000;
1007
1008 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
1009 last_update = now;
1010
1011 if (t1 != UINT32_MAX)
1012 t1 -= elapsed;
1013
1014 if (t2 != UINT32_MAX)
1015 t2 -= elapsed;
1016
1017 if (t3 != UINT32_MAX)
1018 t3 -= elapsed;
1019
1020 if (t1 < 0)
1021 t1 = 0;
1022
1023 if (t2 < 0)
1024 t2 = 0;
1025
1026 if (t3 < 0)
1027 t3 = 0;
1028 }
1029
1030 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1031 // Delete NA and PD we have in the state from the Advert
1032 odhcp6c_clear_state(STATE_IA_NA);
1033 odhcp6c_clear_state(STATE_IA_PD);
1034 }
1035
1036 if (opt) {
1037 odhcp6c_clear_state(STATE_DNS);
1038 odhcp6c_clear_state(STATE_SEARCH);
1039 odhcp6c_clear_state(STATE_SNTP_IP);
1040 odhcp6c_clear_state(STATE_NTP_IP);
1041 odhcp6c_clear_state(STATE_NTP_FQDN);
1042 odhcp6c_clear_state(STATE_SIP_IP);
1043 odhcp6c_clear_state(STATE_SIP_FQDN);
1044 odhcp6c_clear_state(STATE_AFTR_NAME);
1045 odhcp6c_clear_state(STATE_CER);
1046 odhcp6c_clear_state(STATE_S46_MAPT);
1047 odhcp6c_clear_state(STATE_S46_MAPE);
1048 odhcp6c_clear_state(STATE_S46_LW);
1049 odhcp6c_clear_state(STATE_PASSTHRU);
1050 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1051
1052 // Parse and find all matching IAs
1053 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1054 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1055
1056 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1057 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1058 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1059
1060 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1061 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1062 continue;
1063
1064 // Test ID
1065 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1066 continue;
1067
1068 uint16_t code = DHCPV6_Success;
1069 uint16_t stype, slen;
1070 uint8_t *sdata;
1071 // Get and handle status code
1072 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1073 stype, slen, sdata) {
1074 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1075 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1076 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1077
1078 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1079
1080 if (code == DHCPV6_Success)
1081 continue;
1082
1083 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1084 code, mdata, mlen, handled_status_codes, &ret);
1085
1086 if (ret > 0)
1087 return ret;
1088
1089 break;
1090 }
1091 }
1092
1093 if (code != DHCPV6_Success)
1094 continue;
1095
1096 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1097 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1098 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1099 server_addr = *(struct in6_addr *)odata;
1100
1101 }
1102 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1103 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1104 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1105 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1106
1107 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1108 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1109 if (olen % 16 == 0)
1110 odhcp6c_add_state(STATE_DNS, odata, olen);
1111 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1112 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1113 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1114 if (olen % 16 == 0)
1115 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1116 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1117 uint16_t stype, slen;
1118 uint8_t *sdata;
1119 // Test status and bail if error
1120 dhcpv6_for_each_option(odata, odata + olen,
1121 stype, slen, sdata) {
1122 if (slen == 16 && (stype == NTP_MC_ADDR ||
1123 stype == NTP_SRV_ADDR))
1124 odhcp6c_add_state(STATE_NTP_IP,
1125 sdata, slen);
1126 else if (slen > 0 && stype == NTP_SRV_FQDN)
1127 odhcp6c_add_state(STATE_NTP_FQDN,
1128 sdata, slen);
1129 }
1130 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1131 if (olen == 16)
1132 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1133 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1134 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1135 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1136 refresh = ntohl_unaligned(odata);
1137 } else if (otype == DHCPV6_OPT_AUTH) {
1138 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1139 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1140 if (r->protocol == 3 && r->algorithm == 1 &&
1141 r->reconf_type == 1)
1142 memcpy(reconf_key, r->key, sizeof(r->key));
1143 }
1144 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1145 size_t cur_len;
1146 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1147 if (cur_len == 0)
1148 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1149 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1150 uint32_t sol_max_rt = ntohl_unaligned(odata);
1151 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1152 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1153 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1154 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1155 uint32_t inf_max_rt = ntohl_unaligned(odata);
1156 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1157 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1158 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1159 #ifdef EXT_CER_ID
1160 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1161 sizeof(struct dhcpv6_cer_id)) {
1162 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1163 struct in6_addr any = IN6ADDR_ANY_INIT;
1164 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1165 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1166 #endif
1167 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1168 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1169 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1170 size_t mape_len;
1171 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1172 if (mape_len == 0)
1173 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1174 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1175 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1176 } else
1177 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1178
1179 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1180 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1181 }
1182 }
1183
1184 // Bail out if fatal status code was received
1185 if (ret <= 0)
1186 return ret;
1187
1188 switch (orig) {
1189 case DHCPV6_MSG_REQUEST:
1190 case DHCPV6_MSG_REBIND:
1191 case DHCPV6_MSG_RENEW:
1192 state_IAs = dhcpv6_calc_refresh_timers();
1193 // In case there're no state IA entries
1194 // keep sending request/renew/rebind messages
1195 if (state_IAs == 0) {
1196 ret = 0;
1197 break;
1198 }
1199
1200 if (orig == DHCPV6_MSG_REQUEST) {
1201 // All server candidates can be cleared if not yet bound
1202 if (!odhcp6c_is_bound())
1203 dhcpv6_clear_all_server_cand();
1204
1205 odhcp6c_clear_state(STATE_SERVER_ADDR);
1206 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1207 } else if (orig == DHCPV6_MSG_RENEW) {
1208 // Send further renews if T1 is not set and if
1209 // there're IAs which were not in the Reply message
1210 if (!t1 && state_IAs != updated_IAs) {
1211 if (updated_IAs)
1212 // Publish updates
1213 script_call("updated", 0, false);
1214
1215 /*
1216 * RFC8415 states following in §18.2.10.1 :
1217 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1218 * message, but as this likely indicates that the server that
1219 * responded does not support that IA type, sending immediately is
1220 * unlikely to produce a different result. Therefore, the client
1221 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1222 * wait for the normal retransmission time (as if the Reply message
1223 * had not been received). The client continues to use other
1224 * bindings for which the server did return information
1225 */
1226 ret = -1;
1227 }
1228 } else if (orig == DHCPV6_MSG_REBIND) {
1229 odhcp6c_clear_state(STATE_SERVER_ADDR);
1230 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1231
1232 // Send further rebinds if T1 and T2 is not set and if
1233 // there're IAs which were not in the Reply message
1234 if (!t1 && !t2 && state_IAs != updated_IAs) {
1235 if (updated_IAs)
1236 // Publish updates
1237 script_call("updated", 0, false);
1238
1239 /*
1240 * RFC8415 states following in §18.2.10.1 :
1241 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1242 * message, but as this likely indicates that the server that
1243 * responded does not support that IA type, sending immediately is
1244 * unlikely to produce a different result. Therefore, the client
1245 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1246 * wait for the normal retransmission time (as if the Reply message
1247 * had not been received). The client continues to use other
1248 * bindings for which the server did return information
1249 */
1250 ret = -1;
1251 }
1252 }
1253 break;
1254
1255 case DHCPV6_MSG_INFO_REQ:
1256 // All server candidates can be cleared if not yet bound
1257 if (!odhcp6c_is_bound())
1258 dhcpv6_clear_all_server_cand();
1259
1260 t1 = refresh;
1261 break;
1262
1263 default:
1264 break;
1265 }
1266
1267 return ret;
1268 }
1269
1270 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1271 {
1272 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1273 unsigned int updated_IAs = 0;
1274 uint32_t t1, t2;
1275 uint16_t otype, olen;
1276 uint8_t *odata;
1277 char buf[INET6_ADDRSTRLEN];
1278
1279 t1 = ntohl(ia_hdr->t1);
1280 t2 = ntohl(ia_hdr->t2);
1281
1282 if (t1 > t2)
1283 return 0;
1284
1285 syslog(LOG_INFO, "IAID %04x T1 %d T2 %d", ia_hdr->iaid, t1, t2);
1286
1287 // Update address IA
1288 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1289 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1290 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1291
1292 entry.iaid = ia_hdr->iaid;
1293
1294 if (otype == DHCPV6_OPT_IA_PREFIX) {
1295 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1296 if (olen + 4U < sizeof(*prefix))
1297 continue;
1298
1299 entry.valid = ntohl(prefix->valid);
1300 entry.preferred = ntohl(prefix->preferred);
1301
1302 if (entry.preferred > entry.valid)
1303 continue;
1304
1305 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1306 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1307 if (entry.t1 > entry.t2)
1308 entry.t1 = entry.t2;
1309
1310 entry.length = prefix->prefix;
1311 entry.target = prefix->addr;
1312 uint16_t stype, slen;
1313 uint8_t *sdata;
1314
1315 // Parse PD-exclude
1316 bool ok = true;
1317 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1318 odata + olen, stype, slen, sdata) {
1319 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1320 continue;
1321
1322 uint8_t elen = sdata[0];
1323 if (elen > 64)
1324 elen = 64;
1325
1326 if (entry.length < 32 || elen <= entry.length) {
1327 ok = false;
1328 continue;
1329 }
1330
1331 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1332 if (slen <= bytes) {
1333 ok = false;
1334 continue;
1335 }
1336
1337 uint32_t exclude = 0;
1338 do {
1339 exclude = exclude << 8 | sdata[bytes];
1340 } while (--bytes);
1341
1342 exclude >>= 8 - ((elen - entry.length) % 8);
1343 exclude <<= 64 - elen;
1344
1345 // Abusing router & priority fields for exclusion
1346 entry.router = entry.target;
1347 entry.router.s6_addr32[1] |= htonl(exclude);
1348 entry.priority = elen;
1349 }
1350
1351 if (ok) {
1352 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1353 updated_IAs++;
1354
1355 syslog(LOG_INFO, "%s/%d preferred %d valid %d",
1356 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1357 entry.length, entry.preferred , entry.valid);
1358 }
1359
1360 entry.priority = 0;
1361 memset(&entry.router, 0, sizeof(entry.router));
1362 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1363 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1364 if (olen + 4U < sizeof(*addr))
1365 continue;
1366
1367 entry.preferred = ntohl(addr->preferred);
1368 entry.valid = ntohl(addr->valid);
1369
1370 if (entry.preferred > entry.valid)
1371 continue;
1372
1373 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1374 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1375 if (entry.t1 > entry.t2)
1376 entry.t1 = entry.t2;
1377
1378 entry.length = 128;
1379 entry.target = addr->addr;
1380
1381 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1382 updated_IAs++;
1383
1384 syslog(LOG_INFO, "%s preferred %d valid %d",
1385 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1386 entry.preferred , entry.valid);
1387 }
1388 }
1389
1390 return updated_IAs;
1391 }
1392
1393 static unsigned int dhcpv6_calc_refresh_timers(void)
1394 {
1395 struct odhcp6c_entry *e;
1396 size_t ia_na_entries, ia_pd_entries, i;
1397 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1398
1399 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1400 ia_na_entries /= sizeof(*e);
1401
1402 for (i = 0; i < ia_na_entries; i++) {
1403 if (e[i].t1 < l_t1)
1404 l_t1 = e[i].t1;
1405
1406 if (e[i].t2 < l_t2)
1407 l_t2 = e[i].t2;
1408
1409 if (e[i].valid > l_t3)
1410 l_t3 = e[i].valid;
1411 }
1412
1413 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1414 ia_pd_entries /= sizeof(*e);
1415
1416 for (i = 0; i < ia_pd_entries; i++) {
1417 if (e[i].t1 < l_t1)
1418 l_t1 = e[i].t1;
1419
1420 if (e[i].t2 < l_t2)
1421 l_t2 = e[i].t2;
1422
1423 if (e[i].valid > l_t3)
1424 l_t3 = e[i].valid;
1425 }
1426
1427 if (ia_pd_entries || ia_na_entries) {
1428 t1 = l_t1;
1429 t2 = l_t2;
1430 t3 = l_t3;
1431
1432 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
1433 }
1434
1435 return (unsigned int)(ia_pd_entries + ia_na_entries);
1436 }
1437
1438 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1439 const void *status_msg, int len)
1440 {
1441 const char *src = status_msg;
1442 char buf[len + 3];
1443 char *dst = buf;
1444
1445 if (len) {
1446 *dst++ = '(';
1447 while (len--) {
1448 *dst = isprint((unsigned char)*src) ? *src : '?';
1449 src++;
1450 dst++;
1451 }
1452 *dst++ = ')';
1453 }
1454
1455 *dst = 0;
1456
1457 syslog(LOG_WARNING, "Server returned %s status %i %s",
1458 scope, code, buf);
1459 }
1460
1461 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1462 const uint16_t code, const void *status_msg, const int len,
1463 int *ret)
1464 {
1465 dhcpv6_log_status_code(code, "message", status_msg, len);
1466
1467 switch (code) {
1468 case DHCPV6_UnspecFail:
1469 // Generic failure
1470 *ret = 0;
1471 break;
1472
1473 case DHCPV6_UseMulticast:
1474 switch(orig) {
1475 case DHCPV6_MSG_REQUEST:
1476 case DHCPV6_MSG_RENEW:
1477 case DHCPV6_MSG_RELEASE:
1478 case DHCPV6_MSG_DECLINE:
1479 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1480 server_addr = in6addr_any;
1481 *ret = 0;
1482 break;
1483 default:
1484 break;
1485 }
1486 break;
1487
1488 case DHCPV6_NoAddrsAvail:
1489 case DHCPV6_NoPrefixAvail:
1490 if (orig == DHCPV6_MSG_REQUEST)
1491 *ret = 0; // Failure
1492 break;
1493
1494 default:
1495 break;
1496 }
1497 }
1498
1499 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1500 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1501 const void *status_msg, const int len,
1502 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1503 {
1504 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1505 "IA_NA" : "IA_PD", status_msg, len);
1506
1507 switch (code) {
1508 case DHCPV6_NoBinding:
1509 switch (orig) {
1510 case DHCPV6_MSG_RENEW:
1511 case DHCPV6_MSG_REBIND:
1512 if ((*ret > 0) && !handled_status_codes[code])
1513 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1514 break;
1515
1516 default:
1517 break;
1518 }
1519 break;
1520
1521 default:
1522 *ret = 0;
1523 break;
1524 }
1525 }
1526
1527 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1528 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1529 {
1530 size_t cand_len, i;
1531 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1532
1533 // Remove identical duid server candidate
1534 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1535 if (cand->duid_len == c[i].duid_len &&
1536 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1537 free(c[i].ia_na);
1538 free(c[i].ia_pd);
1539 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1540 break;
1541 }
1542 }
1543
1544 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1545 i < cand_len / sizeof(*c); ++i) {
1546 if (c[i].preference < cand->preference)
1547 break;
1548 }
1549
1550 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1551 free(cand->ia_na);
1552 free(cand->ia_pd);
1553 }
1554 }
1555
1556 static void dhcpv6_clear_all_server_cand(void)
1557 {
1558 size_t cand_len, i;
1559 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1560
1561 // Server candidates need deep delete for IA_NA/IA_PD
1562 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1563 free(c[i].ia_na);
1564 free(c[i].ia_pd);
1565 }
1566 odhcp6c_clear_state(STATE_SERVER_CAND);
1567 }
1568
1569 int dhcpv6_promote_server_cand(void)
1570 {
1571 size_t cand_len;
1572 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1573 uint16_t hdr[2];
1574 int ret = DHCPV6_STATELESS;
1575
1576 // Clear lingering candidate state info
1577 odhcp6c_clear_state(STATE_SERVER_ID);
1578 odhcp6c_clear_state(STATE_IA_NA);
1579 odhcp6c_clear_state(STATE_IA_PD);
1580
1581 if (!cand_len)
1582 return -1;
1583
1584 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1585 na_mode = IA_MODE_NONE;
1586
1587 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1588 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1589
1590 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1591 }
1592
1593 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1594 hdr[1] = htons(cand->duid_len);
1595 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1596 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1597 accept_reconfig = cand->wants_reconfigure;
1598
1599 if (cand->ia_na_len) {
1600 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1601 free(cand->ia_na);
1602 if (na_mode != IA_MODE_NONE)
1603 ret = DHCPV6_STATEFUL;
1604 }
1605
1606 if (cand->ia_pd_len) {
1607 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1608 free(cand->ia_pd);
1609 if (pd_mode != IA_MODE_NONE)
1610 ret = DHCPV6_STATEFUL;
1611 }
1612
1613 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1614 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1615
1616 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1617
1618 return ret;
1619 }
Openwrt DHCPv6 Client