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dhcpv6: fix regression
[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 const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf;
664
665 // Check for pending signal
666 if (odhcp6c_signal_process())
667 return -1;
668
669 // Set timeout for receiving
670 uint64_t t = round_end - round_start;
671 struct timeval tv = {t / 1000, (t % 1000) * 1000};
672 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
673 &tv, sizeof(tv)) < 0)
674 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
675 strerror(errno));
676
677 // Receive cycle
678 len = recvmsg(sock, &msg, 0);
679 if (len < 0)
680 continue;
681
682 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
683 ch = CMSG_NXTHDR(&msg, ch)) {
684 if (ch->cmsg_level == SOL_IPV6 &&
685 ch->cmsg_type == IPV6_PKTINFO) {
686 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
687 break;
688 }
689 }
690
691 if (pktinfo == NULL) {
692 len = -1;
693 continue;
694 }
695
696 if (!dhcpv6_response_is_valid(buf, len, trid,
697 type, &pktinfo->ipi6_addr)) {
698 len = -1;
699 continue;
700 }
701
702 uint8_t *opt = &buf[4];
703 uint8_t *opt_end = opt + len - 4;
704
705 round_start = odhcp6c_get_milli_time();
706 elapsed = round_start - start;
707 syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms",
708 dhcpv6_msg_to_str(hdr->msg_type), elapsed);
709
710 if (retx->handler_reply)
711 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
712
713 if (len > 0 && round_end - round_start > 1000)
714 round_end = 1000 + round_start;
715 }
716
717 // Allow
718 if (retx->handler_finish)
719 len = retx->handler_finish();
720 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
721 (!retx->max_rc || rc < retx->max_rc));
722 return len;
723 }
724
725 // Message validation checks according to RFC3315 chapter 15
726 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
727 const uint8_t transaction[3], enum dhcpv6_msg type,
728 const struct in6_addr *daddr)
729 {
730 const struct dhcpv6_header *rep = buf;
731 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
732 transaction, sizeof(rep->tr_id)))
733 return false; // Invalid reply
734
735 if (type == DHCPV6_MSG_SOLICIT) {
736 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
737 rep->msg_type != DHCPV6_MSG_REPLY)
738 return false;
739
740 } else if (type == DHCPV6_MSG_UNKNOWN) {
741 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
742 return false;
743
744 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
745 return false;
746
747 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
748 rcmsg = DHCPV6_MSG_UNKNOWN;
749 uint16_t otype, olen = UINT16_MAX;
750 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
751 ia_present = false, options_valid = true;
752
753 size_t client_id_len, server_id_len;
754 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
755 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
756
757 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
758 if (otype == DHCPV6_OPT_CLIENTID) {
759 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
760 &odata[-4], client_id, client_id_len);
761 } else if (otype == DHCPV6_OPT_SERVERID) {
762 if (server_id_len)
763 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
764 &odata[-4], server_id, server_id_len);
765 else
766 serverid_ok = true;
767 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
768 sizeof(struct dhcpv6_auth_reconfigure)) {
769 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
770 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
771 continue;
772
773 md5_ctx_t md5;
774 uint8_t serverhash[16], secretbytes[64];
775 uint32_t hash[4];
776 memcpy(serverhash, r->key, sizeof(serverhash));
777 memset(r->key, 0, sizeof(r->key));
778
779 memset(secretbytes, 0, sizeof(secretbytes));
780 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
781
782 for (size_t i = 0; i < sizeof(secretbytes); ++i)
783 secretbytes[i] ^= 0x36;
784
785 md5_begin(&md5);
786 md5_hash(secretbytes, sizeof(secretbytes), &md5);
787 md5_hash(buf, len, &md5);
788 md5_end(hash, &md5);
789
790 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
791 secretbytes[i] ^= 0x36;
792 secretbytes[i] ^= 0x5c;
793 }
794
795 md5_begin(&md5);
796 md5_hash(secretbytes, sizeof(secretbytes), &md5);
797 md5_hash(hash, 16, &md5);
798 md5_end(hash, &md5);
799
800 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
801 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
802 rcmsg = odata[0];
803 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
804 ia_present = true;
805 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
806 options_valid = false;
807 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
808 (otype == DHCPV6_OPT_PD_EXCLUDE))
809 // Options are not allowed on global level
810 options_valid = false;
811 }
812
813 if (!options_valid || ((odata + olen) > end))
814 return false;
815
816 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
817 return false;
818
819 if (rep->msg_type == DHCPV6_MSG_RECONF) {
820 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
821 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
822 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
823 return false;
824 }
825
826 return clientid_ok && serverid_ok;
827 }
828
829 int dhcpv6_poll_reconfigure(void)
830 {
831 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
832
833 if (ret != -1)
834 ret = dhcpv6_request(ret);
835
836 return ret;
837 }
838
839 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
840 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
841 {
842 uint16_t otype, olen;
843 uint8_t *odata;
844 enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN;
845
846 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
847 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
848 switch (odata[0]) {
849 case DHCPV6_MSG_REBIND:
850 if (t2 != UINT32_MAX)
851 t2 = 0;
852 // Fall through
853 case DHCPV6_MSG_RENEW:
854 if (t1 != UINT32_MAX)
855 t1 = 0;
856 // Fall through
857 case DHCPV6_MSG_INFO_REQ:
858 msg = odata[0];
859 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s",
860 dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF));
861 break;
862
863 default:
864 break;
865 }
866 }
867 }
868
869 if (msg != DHCPV6_MSG_UNKNOWN)
870 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
871
872 return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg);
873 }
874
875 // Collect all advertised servers
876 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
877 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
878 {
879 uint16_t olen, otype;
880 uint8_t *odata, pref = 0;
881 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
882 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
883 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
884 bool have_na = false;
885 int have_pd = 0;
886
887 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
888 if (orig == DHCPV6_MSG_SOLICIT &&
889 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
890 (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
891 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
892 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
893 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
894 }
895
896 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
897 memcpy(cand.duid, odata, olen);
898 cand.duid_len = olen;
899 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
900 cand.preference >= 0) {
901 cand.preference = pref = odata[0];
902 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
903 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
904 cand.server_addr = *(struct in6_addr *)odata;
905
906 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
907 cand.wants_reconfigure = true;
908 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
909 uint32_t sol_max_rt = ntohl_unaligned(odata);
910 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
911 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
912 cand.sol_max_rt = sol_max_rt;
913
914 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
915 uint32_t inf_max_rt = ntohl_unaligned(odata);
916 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
917 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
918 cand.inf_max_rt = inf_max_rt;
919
920 } else if (otype == DHCPV6_OPT_IA_PD &&
921 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
922 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
923 uint8_t *oend = odata + olen, *d;
924 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
925 if (otype == DHCPV6_OPT_IA_PREFIX &&
926 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
927 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
928 have_pd = p->prefix;
929 }
930 }
931 } else if (otype == DHCPV6_OPT_IA_NA &&
932 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
933 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
934 uint8_t *oend = odata + olen, *d;
935
936 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
937 if (otype == DHCPV6_OPT_IA_ADDR &&
938 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
939 have_na = true;
940 }
941 }
942 }
943
944 if ((!have_na && na_mode == IA_MODE_FORCE) ||
945 (!have_pd && pd_mode == IA_MODE_FORCE)) {
946 /*
947 * RFC7083 states to process the SOL_MAX_RT and
948 * INF_MAX_RT options even if the DHCPv6 server
949 * did not propose any IA_NA and/or IA_PD
950 */
951 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
952 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
953 return -1;
954 }
955
956 if (na_mode != IA_MODE_NONE && !have_na) {
957 cand.has_noaddravail = true;
958 cand.preference -= 1000;
959 }
960
961 if (pd_mode != IA_MODE_NONE) {
962 if (have_pd)
963 cand.preference += 2000 + (128 - have_pd);
964 else
965 cand.preference -= 2000;
966 }
967
968 if (cand.duid_len > 0) {
969 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
970 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
971 dhcpv6_add_server_cand(&cand);
972 }
973
974 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
975 }
976
977 static int dhcpv6_commit_advert(void)
978 {
979 return dhcpv6_promote_server_cand();
980 }
981
982 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
983 const void *opt, const void *end, const struct sockaddr_in6 *from)
984 {
985 dhcpv6_handle_advert(orig, rc, opt, end, from);
986 if (dhcpv6_commit_advert() < 0)
987 return -1;
988
989 return dhcpv6_handle_reply(orig, rc, opt, end, from);
990 }
991
992 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
993 const void *opt, const void *end, const struct sockaddr_in6 *from)
994 {
995 uint8_t *odata;
996 uint16_t otype, olen;
997 uint32_t refresh = 86400;
998 int ret = 1;
999 unsigned int state_IAs;
1000 unsigned int updated_IAs = 0;
1001 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
1002
1003 odhcp6c_expire();
1004
1005 if (orig == DHCPV6_MSG_UNKNOWN) {
1006 static time_t last_update = 0;
1007 time_t now = odhcp6c_get_milli_time() / 1000;
1008
1009 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
1010 last_update = now;
1011
1012 if (t1 != UINT32_MAX)
1013 t1 -= elapsed;
1014
1015 if (t2 != UINT32_MAX)
1016 t2 -= elapsed;
1017
1018 if (t3 != UINT32_MAX)
1019 t3 -= elapsed;
1020
1021 if (t1 < 0)
1022 t1 = 0;
1023
1024 if (t2 < 0)
1025 t2 = 0;
1026
1027 if (t3 < 0)
1028 t3 = 0;
1029 }
1030
1031 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1032 // Delete NA and PD we have in the state from the Advert
1033 odhcp6c_clear_state(STATE_IA_NA);
1034 odhcp6c_clear_state(STATE_IA_PD);
1035 }
1036
1037 if (opt) {
1038 odhcp6c_clear_state(STATE_DNS);
1039 odhcp6c_clear_state(STATE_SEARCH);
1040 odhcp6c_clear_state(STATE_SNTP_IP);
1041 odhcp6c_clear_state(STATE_NTP_IP);
1042 odhcp6c_clear_state(STATE_NTP_FQDN);
1043 odhcp6c_clear_state(STATE_SIP_IP);
1044 odhcp6c_clear_state(STATE_SIP_FQDN);
1045 odhcp6c_clear_state(STATE_AFTR_NAME);
1046 odhcp6c_clear_state(STATE_CER);
1047 odhcp6c_clear_state(STATE_S46_MAPT);
1048 odhcp6c_clear_state(STATE_S46_MAPE);
1049 odhcp6c_clear_state(STATE_S46_LW);
1050 odhcp6c_clear_state(STATE_PASSTHRU);
1051 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1052
1053 // Parse and find all matching IAs
1054 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1055 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1056
1057 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1058 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1059 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1060
1061 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1062 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1063 continue;
1064
1065 // Test ID
1066 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1067 continue;
1068
1069 uint16_t code = DHCPV6_Success;
1070 uint16_t stype, slen;
1071 uint8_t *sdata;
1072 // Get and handle status code
1073 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1074 stype, slen, sdata) {
1075 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1076 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1077 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1078
1079 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1080
1081 if (code == DHCPV6_Success)
1082 continue;
1083
1084 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1085 code, mdata, mlen, handled_status_codes, &ret);
1086
1087 if (ret > 0)
1088 return ret;
1089
1090 break;
1091 }
1092 }
1093
1094 if (code != DHCPV6_Success)
1095 continue;
1096
1097 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1098 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1099 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1100 server_addr = *(struct in6_addr *)odata;
1101
1102 }
1103 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1104 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1105 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1106 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1107
1108 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1109 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1110 if (olen % 16 == 0)
1111 odhcp6c_add_state(STATE_DNS, odata, olen);
1112 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1113 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1114 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1115 if (olen % 16 == 0)
1116 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1117 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1118 uint16_t stype, slen;
1119 uint8_t *sdata;
1120 // Test status and bail if error
1121 dhcpv6_for_each_option(odata, odata + olen,
1122 stype, slen, sdata) {
1123 if (slen == 16 && (stype == NTP_MC_ADDR ||
1124 stype == NTP_SRV_ADDR))
1125 odhcp6c_add_state(STATE_NTP_IP,
1126 sdata, slen);
1127 else if (slen > 0 && stype == NTP_SRV_FQDN)
1128 odhcp6c_add_state(STATE_NTP_FQDN,
1129 sdata, slen);
1130 }
1131 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1132 if (olen == 16)
1133 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1134 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1135 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1136 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1137 refresh = ntohl_unaligned(odata);
1138 } else if (otype == DHCPV6_OPT_AUTH) {
1139 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1140 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1141 if (r->protocol == 3 && r->algorithm == 1 &&
1142 r->reconf_type == 1)
1143 memcpy(reconf_key, r->key, sizeof(r->key));
1144 }
1145 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1146 size_t cur_len;
1147 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1148 if (cur_len == 0)
1149 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1150 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1151 uint32_t sol_max_rt = ntohl_unaligned(odata);
1152 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1153 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1154 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1155 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1156 uint32_t inf_max_rt = ntohl_unaligned(odata);
1157 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1158 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1159 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1160 #ifdef EXT_CER_ID
1161 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1162 sizeof(struct dhcpv6_cer_id)) {
1163 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1164 struct in6_addr any = IN6ADDR_ANY_INIT;
1165 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1166 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1167 #endif
1168 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1169 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1170 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1171 size_t mape_len;
1172 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1173 if (mape_len == 0)
1174 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1175 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1176 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1177 } else
1178 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1179
1180 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1181 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1182 }
1183 }
1184
1185 // Bail out if fatal status code was received
1186 if (ret <= 0)
1187 return ret;
1188
1189 switch (orig) {
1190 case DHCPV6_MSG_REQUEST:
1191 case DHCPV6_MSG_REBIND:
1192 case DHCPV6_MSG_RENEW:
1193 state_IAs = dhcpv6_calc_refresh_timers();
1194 // In case there're no state IA entries
1195 // keep sending request/renew/rebind messages
1196 if (state_IAs == 0) {
1197 ret = 0;
1198 break;
1199 }
1200
1201 if (orig == DHCPV6_MSG_REQUEST) {
1202 // All server candidates can be cleared if not yet bound
1203 if (!odhcp6c_is_bound())
1204 dhcpv6_clear_all_server_cand();
1205
1206 odhcp6c_clear_state(STATE_SERVER_ADDR);
1207 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1208 } else if (orig == DHCPV6_MSG_RENEW) {
1209 // Send further renews if T1 is not set and if
1210 // there're IAs which were not in the Reply message
1211 if (!t1 && state_IAs != updated_IAs) {
1212 if (updated_IAs)
1213 // Publish updates
1214 script_call("updated", 0, false);
1215
1216 /*
1217 * RFC8415 states following in §18.2.10.1 :
1218 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1219 * message, but as this likely indicates that the server that
1220 * responded does not support that IA type, sending immediately is
1221 * unlikely to produce a different result. Therefore, the client
1222 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1223 * wait for the normal retransmission time (as if the Reply message
1224 * had not been received). The client continues to use other
1225 * bindings for which the server did return information
1226 */
1227 ret = -1;
1228 }
1229 } else if (orig == DHCPV6_MSG_REBIND) {
1230 odhcp6c_clear_state(STATE_SERVER_ADDR);
1231 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1232
1233 // Send further rebinds if T1 and T2 is not set and if
1234 // there're IAs which were not in the Reply message
1235 if (!t1 && !t2 && state_IAs != updated_IAs) {
1236 if (updated_IAs)
1237 // Publish updates
1238 script_call("updated", 0, false);
1239
1240 /*
1241 * RFC8415 states following in §18.2.10.1 :
1242 * Sends a Renew/Rebind if any of the IAs are not in the Reply
1243 * message, but as this likely indicates that the server that
1244 * responded does not support that IA type, sending immediately is
1245 * unlikely to produce a different result. Therefore, the client
1246 * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1247 * wait for the normal retransmission time (as if the Reply message
1248 * had not been received). The client continues to use other
1249 * bindings for which the server did return information
1250 */
1251 ret = -1;
1252 }
1253 }
1254 break;
1255
1256 case DHCPV6_MSG_INFO_REQ:
1257 // All server candidates can be cleared if not yet bound
1258 if (!odhcp6c_is_bound())
1259 dhcpv6_clear_all_server_cand();
1260
1261 t1 = refresh;
1262 break;
1263
1264 default:
1265 break;
1266 }
1267
1268 return ret;
1269 }
1270
1271 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1272 {
1273 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1274 unsigned int updated_IAs = 0;
1275 uint32_t t1, t2;
1276 uint16_t otype, olen;
1277 uint8_t *odata;
1278 char buf[INET6_ADDRSTRLEN];
1279
1280 t1 = ntohl(ia_hdr->t1);
1281 t2 = ntohl(ia_hdr->t2);
1282
1283 if (t1 > t2)
1284 return 0;
1285
1286 syslog(LOG_INFO, "IAID %04x T1 %d T2 %d", htonl(ia_hdr->iaid), t1, t2);
1287
1288 // Update address IA
1289 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1290 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1291 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1292
1293 entry.iaid = ia_hdr->iaid;
1294
1295 if (otype == DHCPV6_OPT_IA_PREFIX) {
1296 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1297 if (olen + 4U < sizeof(*prefix))
1298 continue;
1299
1300 entry.valid = ntohl(prefix->valid);
1301 entry.preferred = ntohl(prefix->preferred);
1302
1303 if (entry.preferred > entry.valid)
1304 continue;
1305
1306 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1307 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1308 if (entry.t1 > entry.t2)
1309 entry.t1 = entry.t2;
1310
1311 entry.length = prefix->prefix;
1312 entry.target = prefix->addr;
1313 uint16_t stype, slen;
1314 uint8_t *sdata;
1315
1316 // Parse PD-exclude
1317 bool ok = true;
1318 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1319 odata + olen, stype, slen, sdata) {
1320 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1321 continue;
1322
1323 uint8_t elen = sdata[0];
1324 if (elen > 64)
1325 elen = 64;
1326
1327 if (entry.length < 32 || elen <= entry.length) {
1328 ok = false;
1329 continue;
1330 }
1331
1332 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1333 if (slen <= bytes) {
1334 ok = false;
1335 continue;
1336 }
1337
1338 uint32_t exclude = 0;
1339 do {
1340 exclude = exclude << 8 | sdata[bytes];
1341 } while (--bytes);
1342
1343 exclude >>= 8 - ((elen - entry.length) % 8);
1344 exclude <<= 64 - elen;
1345
1346 // Abusing router & priority fields for exclusion
1347 entry.router = entry.target;
1348 entry.router.s6_addr32[1] |= htonl(exclude);
1349 entry.priority = elen;
1350 }
1351
1352 if (ok) {
1353 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1354 updated_IAs++;
1355
1356 syslog(LOG_INFO, "%s/%d preferred %d valid %d",
1357 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1358 entry.length, entry.preferred , entry.valid);
1359 }
1360
1361 entry.priority = 0;
1362 memset(&entry.router, 0, sizeof(entry.router));
1363 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1364 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1365 if (olen + 4U < sizeof(*addr))
1366 continue;
1367
1368 entry.preferred = ntohl(addr->preferred);
1369 entry.valid = ntohl(addr->valid);
1370
1371 if (entry.preferred > entry.valid)
1372 continue;
1373
1374 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1375 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1376 if (entry.t1 > entry.t2)
1377 entry.t1 = entry.t2;
1378
1379 entry.length = 128;
1380 entry.target = addr->addr;
1381
1382 if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1383 updated_IAs++;
1384
1385 syslog(LOG_INFO, "%s preferred %d valid %d",
1386 inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1387 entry.preferred , entry.valid);
1388 }
1389 }
1390
1391 return updated_IAs;
1392 }
1393
1394 static unsigned int dhcpv6_calc_refresh_timers(void)
1395 {
1396 struct odhcp6c_entry *e;
1397 size_t ia_na_entries, ia_pd_entries, i;
1398 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1399
1400 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1401 ia_na_entries /= sizeof(*e);
1402
1403 for (i = 0; i < ia_na_entries; i++) {
1404 if (e[i].t1 < l_t1)
1405 l_t1 = e[i].t1;
1406
1407 if (e[i].t2 < l_t2)
1408 l_t2 = e[i].t2;
1409
1410 if (e[i].valid > l_t3)
1411 l_t3 = e[i].valid;
1412 }
1413
1414 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1415 ia_pd_entries /= sizeof(*e);
1416
1417 for (i = 0; i < ia_pd_entries; i++) {
1418 if (e[i].t1 < l_t1)
1419 l_t1 = e[i].t1;
1420
1421 if (e[i].t2 < l_t2)
1422 l_t2 = e[i].t2;
1423
1424 if (e[i].valid > l_t3)
1425 l_t3 = e[i].valid;
1426 }
1427
1428 if (ia_pd_entries || ia_na_entries) {
1429 t1 = l_t1;
1430 t2 = l_t2;
1431 t3 = l_t3;
1432
1433 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
1434 }
1435
1436 return (unsigned int)(ia_pd_entries + ia_na_entries);
1437 }
1438
1439 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1440 const void *status_msg, int len)
1441 {
1442 const char *src = status_msg;
1443 char buf[len + 3];
1444 char *dst = buf;
1445
1446 if (len) {
1447 *dst++ = '(';
1448 while (len--) {
1449 *dst = isprint((unsigned char)*src) ? *src : '?';
1450 src++;
1451 dst++;
1452 }
1453 *dst++ = ')';
1454 }
1455
1456 *dst = 0;
1457
1458 syslog(LOG_WARNING, "Server returned %s status %i %s",
1459 scope, code, buf);
1460 }
1461
1462 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1463 const uint16_t code, const void *status_msg, const int len,
1464 int *ret)
1465 {
1466 dhcpv6_log_status_code(code, "message", status_msg, len);
1467
1468 switch (code) {
1469 case DHCPV6_UnspecFail:
1470 // Generic failure
1471 *ret = 0;
1472 break;
1473
1474 case DHCPV6_UseMulticast:
1475 switch(orig) {
1476 case DHCPV6_MSG_REQUEST:
1477 case DHCPV6_MSG_RENEW:
1478 case DHCPV6_MSG_RELEASE:
1479 case DHCPV6_MSG_DECLINE:
1480 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1481 server_addr = in6addr_any;
1482 *ret = 0;
1483 break;
1484 default:
1485 break;
1486 }
1487 break;
1488
1489 case DHCPV6_NoAddrsAvail:
1490 case DHCPV6_NoPrefixAvail:
1491 if (orig == DHCPV6_MSG_REQUEST)
1492 *ret = 0; // Failure
1493 break;
1494
1495 default:
1496 break;
1497 }
1498 }
1499
1500 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1501 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1502 const void *status_msg, const int len,
1503 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1504 {
1505 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1506 "IA_NA" : "IA_PD", status_msg, len);
1507
1508 switch (code) {
1509 case DHCPV6_NoBinding:
1510 switch (orig) {
1511 case DHCPV6_MSG_RENEW:
1512 case DHCPV6_MSG_REBIND:
1513 if ((*ret > 0) && !handled_status_codes[code])
1514 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1515 break;
1516
1517 default:
1518 break;
1519 }
1520 break;
1521
1522 default:
1523 *ret = 0;
1524 break;
1525 }
1526 }
1527
1528 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1529 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1530 {
1531 size_t cand_len, i;
1532 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1533
1534 // Remove identical duid server candidate
1535 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1536 if (cand->duid_len == c[i].duid_len &&
1537 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1538 free(c[i].ia_na);
1539 free(c[i].ia_pd);
1540 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1541 break;
1542 }
1543 }
1544
1545 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1546 i < cand_len / sizeof(*c); ++i) {
1547 if (c[i].preference < cand->preference)
1548 break;
1549 }
1550
1551 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1552 free(cand->ia_na);
1553 free(cand->ia_pd);
1554 }
1555 }
1556
1557 static void dhcpv6_clear_all_server_cand(void)
1558 {
1559 size_t cand_len, i;
1560 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1561
1562 // Server candidates need deep delete for IA_NA/IA_PD
1563 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1564 free(c[i].ia_na);
1565 free(c[i].ia_pd);
1566 }
1567 odhcp6c_clear_state(STATE_SERVER_CAND);
1568 }
1569
1570 int dhcpv6_promote_server_cand(void)
1571 {
1572 size_t cand_len;
1573 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1574 uint16_t hdr[2];
1575 int ret = DHCPV6_STATELESS;
1576
1577 // Clear lingering candidate state info
1578 odhcp6c_clear_state(STATE_SERVER_ID);
1579 odhcp6c_clear_state(STATE_IA_NA);
1580 odhcp6c_clear_state(STATE_IA_PD);
1581
1582 if (!cand_len)
1583 return -1;
1584
1585 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1586 na_mode = IA_MODE_NONE;
1587
1588 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1589 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1590
1591 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1592 }
1593
1594 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1595 hdr[1] = htons(cand->duid_len);
1596 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1597 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1598 accept_reconfig = cand->wants_reconfigure;
1599
1600 if (cand->ia_na_len) {
1601 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1602 free(cand->ia_na);
1603 if (na_mode != IA_MODE_NONE)
1604 ret = DHCPV6_STATEFUL;
1605 }
1606
1607 if (cand->ia_pd_len) {
1608 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1609 free(cand->ia_pd);
1610 if (pd_mode != IA_MODE_NONE)
1611 ret = DHCPV6_STATEFUL;
1612 }
1613
1614 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1615 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1616
1617 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1618
1619 return ret;
1620 }
Openwrt DHCPv6 Client