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treewide: improve error handling
[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 int dhcpv6_parse_ia(void *opt, void *end);
63
64 static 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 int request_prefix = -1;
107 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
108 static bool accept_reconfig = false;
109 // Server unicast address
110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
111
112 // Reconfigure key
113 static uint8_t reconf_key[16];
114
115 // client options
116 static unsigned int client_options = 0;
117
118 static uint32_t ntohl_unaligned(const uint8_t *data)
119 {
120 uint32_t buf;
121
122 memcpy(&buf, data, sizeof(buf));
123 return ntohl(buf);
124 }
125
126 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
127 {
128 client_options = options;
129 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
130
131 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
132 if (sock < 0)
133 goto failure;
134
135 // Detect interface
136 struct ifreq ifr;
137 memset(&ifr, 0, sizeof(ifr));
138 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
139 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
140 goto failure;
141
142 ifindex = ifr.ifr_ifindex;
143
144 // Create client DUID
145 size_t client_id_len;
146 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
147 if (client_id_len == 0) {
148 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
149 DHCPV6_DUID_LLADDR, 0, 1};
150
151 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
152 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
153
154 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
155 struct ifreq ifs[100], *ifp, *ifend;
156 struct ifconf ifc;
157 ifc.ifc_req = ifs;
158 ifc.ifc_len = sizeof(ifs);
159
160 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
161 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
162 // If our interface doesn't have an address...
163 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
164 for (ifp = ifc.ifc_req; ifp < ifend &&
165 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
166 memcpy(ifr.ifr_name, ifp->ifr_name,
167 sizeof(ifr.ifr_name));
168 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
169 continue;
170
171 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
172 ETHER_ADDR_LEN);
173 }
174 }
175
176 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
177 }
178
179 // Create ORO
180 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
181 uint16_t oro[] = {
182 htons(DHCPV6_OPT_SIP_SERVER_D),
183 htons(DHCPV6_OPT_SIP_SERVER_A),
184 htons(DHCPV6_OPT_DNS_SERVERS),
185 htons(DHCPV6_OPT_DNS_DOMAIN),
186 htons(DHCPV6_OPT_UNICAST),
187 htons(DHCPV6_OPT_SNTP_SERVERS),
188 htons(DHCPV6_OPT_NTP_SERVER),
189 htons(DHCPV6_OPT_AFTR_NAME),
190 htons(DHCPV6_OPT_PD_EXCLUDE),
191 htons(DHCPV6_OPT_SOL_MAX_RT),
192 htons(DHCPV6_OPT_INF_MAX_RT),
193 #ifdef EXT_CER_ID
194 htons(DHCPV6_OPT_CER_ID),
195 #endif
196 htons(DHCPV6_OPT_S46_CONT_MAPE),
197 htons(DHCPV6_OPT_S46_CONT_MAPT),
198 htons(DHCPV6_OPT_S46_CONT_LW),
199 };
200 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
201 }
202
203 // Configure IPv6-options
204 int val = 1;
205 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
206 goto failure;
207
208 if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
209 goto failure;
210
211 if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
212 goto failure;
213
214 if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
215 goto failure;
216
217 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
218 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
219
220 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
221 goto failure;
222
223 return 0;
224
225 failure:
226 if (sock >= 0)
227 close(sock);
228
229 return -1;
230 }
231
232 enum {
233 IOV_HDR=0,
234 IOV_ORO,
235 IOV_ORO_REFRESH,
236 IOV_CL_ID,
237 IOV_SRV_ID,
238 IOV_OPTS,
239 IOV_RECONF_ACCEPT,
240 IOV_FQDN,
241 IOV_HDR_IA_NA,
242 IOV_IA_NA,
243 IOV_IA_PD,
244 IOV_TOTAL
245 };
246
247 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
248 {
249 int mode = DHCPV6_UNKNOWN;
250
251 na_mode = na;
252 pd_mode = pd;
253
254 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
255 mode = DHCPV6_STATELESS;
256 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
257 mode = DHCPV6_STATEFUL;
258
259 return mode;
260 }
261
262 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
263 {
264 // Build FQDN
265 char fqdn_buf[256];
266 gethostname(fqdn_buf, sizeof(fqdn_buf));
267 struct {
268 uint16_t type;
269 uint16_t len;
270 uint8_t flags;
271 uint8_t data[256];
272 } fqdn;
273 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
274 sizeof(fqdn.data), NULL, NULL);
275 fqdn.type = htons(DHCPV6_OPT_FQDN);
276 fqdn.len = htons(fqdn_len - 4);
277 fqdn.flags = 0;
278
279 // Build Client ID
280 size_t cl_id_len;
281 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
282
283 // Get Server ID
284 size_t srv_id_len;
285 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
286
287 // Build IA_PDs
288 size_t ia_pd_entries = 0, ia_pd_len = 0;
289 uint8_t *ia_pd;
290
291 if (type == DHCPV6_MSG_SOLICIT) {
292 odhcp6c_clear_state(STATE_IA_PD);
293 size_t n_prefixes;
294 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
295 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
296
297 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
298
299 for (size_t i = 0; i < n_prefixes; i++) {
300 struct dhcpv6_ia_hdr hdr_ia_pd = {
301 htons(DHCPV6_OPT_IA_PD),
302 htons(sizeof(hdr_ia_pd) - 4 +
303 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
304 request_prefixes[i].iaid, 0, 0
305 };
306 struct dhcpv6_ia_prefix pref = {
307 .type = htons(DHCPV6_OPT_IA_PREFIX),
308 .len = htons(sizeof(pref) - 4),
309 .prefix = request_prefixes[i].length
310 };
311 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
312 ia_pd_len += sizeof(hdr_ia_pd);
313 if (request_prefixes[i].length) {
314 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
315 ia_pd_len += sizeof(pref);
316 }
317 }
318 } else {
319 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
320 ia_pd_entries /= sizeof(*e);
321
322 // we're too lazy to count our distinct IAIDs,
323 // so just allocate maximally needed space
324 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
325 sizeof(struct dhcpv6_ia_hdr)));
326
327 for (size_t i = 0; i < ia_pd_entries; ++i) {
328 uint32_t iaid = e[i].iaid;
329
330 // check if this is an unprocessed IAID and skip if not.
331 int new_iaid = 1;
332 for (int j = i-1; j >= 0; j--) {
333 if (e[j].iaid == iaid) {
334 new_iaid = 0;
335 break;
336 }
337 }
338
339 if (!new_iaid)
340 continue;
341
342 // construct header
343 struct dhcpv6_ia_hdr hdr_ia_pd = {
344 htons(DHCPV6_OPT_IA_PD),
345 htons(sizeof(hdr_ia_pd) - 4),
346 iaid, 0, 0
347 };
348
349 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
350 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
351 ia_pd_len += sizeof(hdr_ia_pd);
352
353 for (size_t j = i; j < ia_pd_entries; j++) {
354 if (e[j].iaid != iaid)
355 continue;
356
357 uint8_t ex_len = 0;
358 if (e[j].priority > 0)
359 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
360
361 struct dhcpv6_ia_prefix p = {
362 .type = htons(DHCPV6_OPT_IA_PREFIX),
363 .len = htons(sizeof(p) - 4U + ex_len),
364 .prefix = e[j].length,
365 .addr = e[j].target
366 };
367
368 if (type == DHCPV6_MSG_REQUEST) {
369 p.preferred = htonl(e[j].preferred);
370 p.valid = htonl(e[j].valid);
371 }
372
373 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
374 ia_pd_len += sizeof(p);
375
376 if (ex_len) {
377 ia_pd[ia_pd_len++] = 0;
378 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
379 ia_pd[ia_pd_len++] = 0;
380 ia_pd[ia_pd_len++] = ex_len - 4;
381 ia_pd[ia_pd_len++] = e[j].priority;
382
383 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
384 excl >>= (64 - e[j].priority);
385 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
386
387 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
388 ia_pd[ia_pd_len + i] = excl & 0xff;
389 ia_pd_len += ex_len - 5;
390 }
391
392 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
393 }
394 }
395 }
396
397 if (ia_pd_entries > 0)
398 request_prefix = 1;
399
400 // Build IA_NAs
401 size_t ia_na_entries, ia_na_len = 0;
402 void *ia_na = NULL;
403 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
404 ia_na_entries /= sizeof(*e);
405
406 struct dhcpv6_ia_hdr hdr_ia_na = {
407 htons(DHCPV6_OPT_IA_NA),
408 htons(sizeof(hdr_ia_na) - 4),
409 htonl(1), 0, 0
410 };
411
412 struct dhcpv6_ia_addr pa[ia_na_entries];
413 for (size_t i = 0; i < ia_na_entries; ++i) {
414 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
415 pa[i].len = htons(sizeof(pa[i]) - 4U);
416 pa[i].addr = e[i].target;
417
418 if (type == DHCPV6_MSG_REQUEST) {
419 pa[i].preferred = htonl(e[i].preferred);
420 pa[i].valid = htonl(e[i].valid);
421 } else {
422 pa[i].preferred = 0;
423 pa[i].valid = 0;
424 }
425 }
426
427 ia_na = pa;
428 ia_na_len = sizeof(pa);
429 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
430
431 // Reconfigure Accept
432 struct {
433 uint16_t type;
434 uint16_t length;
435 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
436
437 // Request Information Refresh
438 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
439
440 // Option list
441 size_t opts_len;
442 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
443
444 // Prepare Header
445 size_t oro_len;
446 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
447 struct {
448 uint8_t type;
449 uint8_t trid[3];
450 uint16_t elapsed_type;
451 uint16_t elapsed_len;
452 uint16_t elapsed_value;
453 uint16_t oro_type;
454 uint16_t oro_len;
455 } hdr = {
456 type, {trid[0], trid[1], trid[2]},
457 htons(DHCPV6_OPT_ELAPSED), htons(2),
458 htons((ecs > 0xffff) ? 0xffff : ecs),
459 htons(DHCPV6_OPT_ORO), htons(oro_len),
460 };
461
462 struct iovec iov[IOV_TOTAL] = {
463 [IOV_HDR] = {&hdr, sizeof(hdr)},
464 [IOV_ORO] = {oro, oro_len},
465 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
466 [IOV_CL_ID] = {cl_id, cl_id_len},
467 [IOV_SRV_ID] = {srv_id, srv_id_len},
468 [IOV_OPTS] = { opts, opts_len },
469 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
470 [IOV_FQDN] = {&fqdn, fqdn_len},
471 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
472 [IOV_IA_NA] = {ia_na, ia_na_len},
473 [IOV_IA_PD] = {ia_pd, ia_pd_len},
474 };
475
476 size_t cnt = IOV_TOTAL;
477 if (type == DHCPV6_MSG_INFO_REQ) {
478 cnt = 9;
479 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
480 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
481 } else if (!request_prefix)
482 cnt = 13;
483
484 // Disable IAs if not used
485 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
486 iov[IOV_HDR_IA_NA].iov_len = 0;
487
488 if (na_mode == IA_MODE_NONE)
489 iov[IOV_HDR_IA_NA].iov_len = 0;
490
491 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
492 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
493 iov[IOV_RECONF_ACCEPT].iov_len = 0;
494
495 if (!(client_options & DHCPV6_CLIENT_FQDN))
496 iov[IOV_FQDN].iov_len = 0;
497
498 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
499 0, ALL_DHCPV6_RELAYS, ifindex};
500 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
501 .msg_iov = iov, .msg_iovlen = cnt};
502
503 switch (type) {
504 case DHCPV6_MSG_REQUEST:
505 case DHCPV6_MSG_RENEW:
506 case DHCPV6_MSG_RELEASE:
507 case DHCPV6_MSG_DECLINE:
508 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
509 odhcp6c_addr_in_scope(&server_addr)) {
510 srv.sin6_addr = server_addr;
511 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
512 srv.sin6_scope_id = 0;
513 }
514 break;
515 default:
516 break;
517 }
518
519 if (sendmsg(sock, &msg, 0) < 0) {
520 char in6_str[INET6_ADDRSTRLEN];
521
522 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
523 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
524 in6_str, sizeof(in6_str)), strerror(errno));
525 }
526 }
527
528 static int64_t dhcpv6_rand_delay(int64_t time)
529 {
530 int random;
531 odhcp6c_random(&random, sizeof(random));
532
533 return (time * ((int64_t)random % 1000LL)) / 10000LL;
534 }
535
536 int dhcpv6_request(enum dhcpv6_msg type)
537 {
538 uint8_t rc = 0;
539 uint64_t timeout = UINT32_MAX;
540 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
541
542 if (retx->delay) {
543 struct timespec ts = {0, 0};
544 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
545
546 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
547 }
548
549 if (type == DHCPV6_MSG_UNKNOWN)
550 timeout = t1;
551 else if (type == DHCPV6_MSG_RENEW)
552 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
553 else if (type == DHCPV6_MSG_REBIND)
554 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
555
556 if (timeout == 0)
557 return -1;
558
559 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
560 retx->name, timeout, retx->max_rc);
561
562 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
563
564 // Generate transaction ID
565 uint8_t trid[3] = {0, 0, 0};
566 if (type != DHCPV6_MSG_UNKNOWN)
567 odhcp6c_random(trid, sizeof(trid));
568
569 ssize_t len = -1;
570 int64_t rto = 0;
571
572 do {
573 if (rto == 0) {
574 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
575
576 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
577 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
578 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
579
580 rto = (retx->init_timeo * 1000 + delay);
581 } else
582 rto = (2 * rto + dhcpv6_rand_delay(rto));
583
584 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
585 rto = retx->max_timeo * 1000 +
586 dhcpv6_rand_delay(retx->max_timeo * 1000);
587
588 // Calculate end for this round and elapsed time
589 uint64_t round_end = round_start + rto;
590 elapsed = round_start - start;
591
592 // Don't wait too long if timeout differs from infinite
593 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
594 round_end = timeout * 1000 + start;
595
596 // Built and send package
597 switch (type) {
598 case DHCPV6_MSG_UNKNOWN:
599 break;
600 default:
601 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
602 retx->name, elapsed, rc);
603 // Fall through
604 case DHCPV6_MSG_SOLICIT:
605 case DHCPV6_MSG_INFO_REQ:
606 dhcpv6_send(type, trid, elapsed / 10);
607 rc++;
608 }
609
610 // Receive rounds
611 for (; len < 0 && (round_start < round_end);
612 round_start = odhcp6c_get_milli_time()) {
613 uint8_t buf[1536];
614 union {
615 struct cmsghdr hdr;
616 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
617 } cmsg_buf;
618 struct iovec iov = {buf, sizeof(buf)};
619 struct sockaddr_in6 addr;
620 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
621 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
622 .msg_controllen = sizeof(cmsg_buf)};
623 struct in6_pktinfo *pktinfo = NULL;
624
625 // Check for pending signal
626 if (odhcp6c_signal_process())
627 return -1;
628
629 // Set timeout for receiving
630 uint64_t t = round_end - round_start;
631 struct timeval tv = {t / 1000, (t % 1000) * 1000};
632 if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
633 &tv, sizeof(tv)) < 0)
634 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
635 strerror(errno));
636
637 // Receive cycle
638 len = recvmsg(sock, &msg, 0);
639 if (len < 0)
640 continue;
641
642 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
643 ch = CMSG_NXTHDR(&msg, ch)) {
644 if (ch->cmsg_level == SOL_IPV6 &&
645 ch->cmsg_type == IPV6_PKTINFO) {
646 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
647 break;
648 }
649 }
650
651 if (pktinfo == NULL) {
652 len = -1;
653 continue;
654 }
655
656 if (!dhcpv6_response_is_valid(buf, len, trid,
657 type, &pktinfo->ipi6_addr)) {
658 len = -1;
659 continue;
660 }
661
662 uint8_t *opt = &buf[4];
663 uint8_t *opt_end = opt + len - 4;
664
665 round_start = odhcp6c_get_milli_time();
666 elapsed = round_start - start;
667 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
668 elapsed);
669
670 if (retx->handler_reply)
671 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
672
673 if (len > 0 && round_end - round_start > 1000)
674 round_end = 1000 + round_start;
675 }
676
677 // Allow
678 if (retx->handler_finish)
679 len = retx->handler_finish();
680 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
681 (!retx->max_rc || rc < retx->max_rc));
682 return len;
683 }
684
685 // Message validation checks according to RFC3315 chapter 15
686 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
687 const uint8_t transaction[3], enum dhcpv6_msg type,
688 const struct in6_addr *daddr)
689 {
690 const struct dhcpv6_header *rep = buf;
691 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
692 transaction, sizeof(rep->tr_id)))
693 return false; // Invalid reply
694
695 if (type == DHCPV6_MSG_SOLICIT) {
696 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
697 rep->msg_type != DHCPV6_MSG_REPLY)
698 return false;
699
700 } else if (type == DHCPV6_MSG_UNKNOWN) {
701 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
702 return false;
703
704 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
705 return false;
706
707 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
708 rcmsg = DHCPV6_MSG_UNKNOWN;
709 uint16_t otype, olen = UINT16_MAX;
710 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
711 ia_present = false, options_valid = true;
712
713 size_t client_id_len, server_id_len;
714 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
715 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
716
717 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
718 if (otype == DHCPV6_OPT_CLIENTID) {
719 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
720 &odata[-4], client_id, client_id_len);
721 } else if (otype == DHCPV6_OPT_SERVERID) {
722 if (server_id_len)
723 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
724 &odata[-4], server_id, server_id_len);
725 else
726 serverid_ok = true;
727 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
728 sizeof(struct dhcpv6_auth_reconfigure)) {
729 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
730 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
731 continue;
732
733 md5_ctx_t md5;
734 uint8_t serverhash[16], secretbytes[64];
735 uint32_t hash[4];
736 memcpy(serverhash, r->key, sizeof(serverhash));
737 memset(r->key, 0, sizeof(r->key));
738
739 memset(secretbytes, 0, sizeof(secretbytes));
740 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
741
742 for (size_t i = 0; i < sizeof(secretbytes); ++i)
743 secretbytes[i] ^= 0x36;
744
745 md5_begin(&md5);
746 md5_hash(secretbytes, sizeof(secretbytes), &md5);
747 md5_hash(buf, len, &md5);
748 md5_end(hash, &md5);
749
750 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
751 secretbytes[i] ^= 0x36;
752 secretbytes[i] ^= 0x5c;
753 }
754
755 md5_begin(&md5);
756 md5_hash(secretbytes, sizeof(secretbytes), &md5);
757 md5_hash(hash, 16, &md5);
758 md5_end(hash, &md5);
759
760 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
761 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
762 rcmsg = odata[0];
763 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
764 ia_present = true;
765 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
766 options_valid = false;
767 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
768 (otype == DHCPV6_OPT_PD_EXCLUDE))
769 // Options are not allowed on global level
770 options_valid = false;
771 }
772
773 if (!options_valid || ((odata + olen) > end))
774 return false;
775
776 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
777 return false;
778
779 if (rep->msg_type == DHCPV6_MSG_RECONF) {
780 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
781 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
782 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
783 return false;
784 }
785
786 return clientid_ok && serverid_ok;
787 }
788
789 int dhcpv6_poll_reconfigure(void)
790 {
791 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
792
793 if (ret != -1)
794 ret = dhcpv6_request(ret);
795
796 return ret;
797 }
798
799 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
800 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
801 {
802 uint16_t otype, olen;
803 uint8_t *odata;
804 int msg = -1;
805
806 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
807 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
808 switch (odata[0]) {
809 case DHCPV6_MSG_REBIND:
810 if (t2 != UINT32_MAX)
811 t2 = 0;
812 // Fall through
813 case DHCPV6_MSG_RENEW:
814 if (t1 != UINT32_MAX)
815 t1 = 0;
816 // Fall through
817 case DHCPV6_MSG_INFO_REQ:
818 msg = odata[0];
819 break;
820
821 default:
822 break;
823 }
824 }
825 }
826
827 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
828
829 return msg;
830 }
831
832 // Collect all advertised servers
833 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
834 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
835 {
836 uint16_t olen, otype;
837 uint8_t *odata, pref = 0;
838 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
839 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
840 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
841 bool have_na = false;
842 int have_pd = 0;
843
844 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
845 if (orig == DHCPV6_MSG_SOLICIT &&
846 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
847 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
848 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
849 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
850 }
851
852 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
853 memcpy(cand.duid, odata, olen);
854 cand.duid_len = olen;
855 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
856 cand.preference >= 0) {
857 cand.preference = pref = odata[0];
858 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
859 cand.server_addr = *(struct in6_addr *)odata;
860 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
861 cand.wants_reconfigure = true;
862 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
863 uint32_t sol_max_rt = ntohl_unaligned(odata);
864 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
865 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
866 cand.sol_max_rt = sol_max_rt;
867
868 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
869 uint32_t inf_max_rt = ntohl_unaligned(odata);
870 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
871 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
872 cand.inf_max_rt = inf_max_rt;
873
874 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
875 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
876 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
877 uint8_t *oend = odata + olen, *d;
878 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
879 if (otype == DHCPV6_OPT_IA_PREFIX &&
880 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
881 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
882 have_pd = p->prefix;
883 }
884 }
885 } else if (otype == DHCPV6_OPT_IA_NA &&
886 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
887 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
888 uint8_t *oend = odata + olen, *d;
889
890 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
891 if (otype == DHCPV6_OPT_IA_ADDR &&
892 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
893 have_na = true;
894 }
895 }
896 }
897
898 if ((!have_na && na_mode == IA_MODE_FORCE) ||
899 (!have_pd && pd_mode == IA_MODE_FORCE)) {
900 /*
901 * RFC7083 states to process the SOL_MAX_RT and
902 * INF_MAX_RT options even if the DHCPv6 server
903 * did not propose any IA_NA and/or IA_PD
904 */
905 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
906 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
907 return -1;
908 }
909
910 if (na_mode != IA_MODE_NONE && !have_na) {
911 cand.has_noaddravail = true;
912 cand.preference -= 1000;
913 }
914
915 if (pd_mode != IA_MODE_NONE) {
916 if (have_pd)
917 cand.preference += 2000 + (128 - have_pd);
918 else
919 cand.preference -= 2000;
920 }
921
922 if (cand.duid_len > 0) {
923 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
924 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
925 dhcpv6_add_server_cand(&cand);
926 }
927
928 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
929 }
930
931 static int dhcpv6_commit_advert(void)
932 {
933 return dhcpv6_promote_server_cand();
934 }
935
936 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
937 const void *opt, const void *end, const struct sockaddr_in6 *from)
938 {
939 dhcpv6_handle_advert(orig, rc, opt, end, from);
940 if (dhcpv6_commit_advert() < 0)
941 return -1;
942
943 return dhcpv6_handle_reply(orig, rc, opt, end, from);
944 }
945
946 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
947 const void *opt, const void *end, const struct sockaddr_in6 *from)
948 {
949 uint8_t *odata;
950 uint16_t otype, olen;
951 uint32_t refresh = 86400;
952 int ret = 1;
953 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
954
955 odhcp6c_expire();
956
957 if (orig == DHCPV6_MSG_UNKNOWN) {
958 static time_t last_update = 0;
959 time_t now = odhcp6c_get_milli_time() / 1000;
960
961 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
962 last_update = now;
963
964 if (t1 != UINT32_MAX)
965 t1 -= elapsed;
966
967 if (t2 != UINT32_MAX)
968 t2 -= elapsed;
969
970 if (t3 != UINT32_MAX)
971 t3 -= elapsed;
972
973 if (t1 < 0)
974 t1 = 0;
975
976 if (t2 < 0)
977 t2 = 0;
978
979 if (t3 < 0)
980 t3 = 0;
981 }
982
983 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
984 // Delete NA and PD we have in the state from the Advert
985 odhcp6c_clear_state(STATE_IA_NA);
986 odhcp6c_clear_state(STATE_IA_PD);
987 }
988
989 if (opt) {
990 odhcp6c_clear_state(STATE_DNS);
991 odhcp6c_clear_state(STATE_SEARCH);
992 odhcp6c_clear_state(STATE_SNTP_IP);
993 odhcp6c_clear_state(STATE_NTP_IP);
994 odhcp6c_clear_state(STATE_NTP_FQDN);
995 odhcp6c_clear_state(STATE_SIP_IP);
996 odhcp6c_clear_state(STATE_SIP_FQDN);
997 odhcp6c_clear_state(STATE_AFTR_NAME);
998 odhcp6c_clear_state(STATE_CER);
999 odhcp6c_clear_state(STATE_S46_MAPT);
1000 odhcp6c_clear_state(STATE_S46_MAPE);
1001 odhcp6c_clear_state(STATE_S46_LW);
1002 odhcp6c_clear_state(STATE_PASSTHRU);
1003 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1004
1005 // Parse and find all matching IAs
1006 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1007 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1008
1009 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1010 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1011 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1012
1013 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1014 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1015 continue;
1016
1017 // Test ID
1018 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1019 continue;
1020
1021 uint16_t code = DHCPV6_Success;
1022 uint16_t stype, slen;
1023 uint8_t *sdata;
1024 // Get and handle status code
1025 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1026 stype, slen, sdata) {
1027 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1028 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1029 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1030
1031 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1032
1033 if (code == DHCPV6_Success)
1034 continue;
1035
1036 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1037 code, mdata, mlen, handled_status_codes, &ret);
1038
1039 if (ret > 0)
1040 return ret;
1041
1042 break;
1043 }
1044 }
1045
1046 if (code != DHCPV6_Success)
1047 continue;
1048
1049 dhcpv6_parse_ia(ia_hdr, odata + olen);
1050 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr))
1051 server_addr = *(struct in6_addr *)odata;
1052 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1053 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1054 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1055 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1056
1057 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1058 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1059 if (olen % 16 == 0)
1060 odhcp6c_add_state(STATE_DNS, odata, olen);
1061 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1062 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1063 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1064 if (olen % 16 == 0)
1065 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1066 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1067 uint16_t stype, slen;
1068 uint8_t *sdata;
1069 // Test status and bail if error
1070 dhcpv6_for_each_option(odata, odata + olen,
1071 stype, slen, sdata) {
1072 if (slen == 16 && (stype == NTP_MC_ADDR ||
1073 stype == NTP_SRV_ADDR))
1074 odhcp6c_add_state(STATE_NTP_IP,
1075 sdata, slen);
1076 else if (slen > 0 && stype == NTP_SRV_FQDN)
1077 odhcp6c_add_state(STATE_NTP_FQDN,
1078 sdata, slen);
1079 }
1080 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1081 if (olen == 16)
1082 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1083 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1084 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1085 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1086 refresh = ntohl_unaligned(odata);
1087 } else if (otype == DHCPV6_OPT_AUTH) {
1088 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1089 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1090 if (r->protocol == 3 && r->algorithm == 1 &&
1091 r->reconf_type == 1)
1092 memcpy(reconf_key, r->key, sizeof(r->key));
1093 }
1094 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1095 size_t cur_len;
1096 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1097 if (cur_len == 0)
1098 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1099 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1100 uint32_t sol_max_rt = ntohl_unaligned(odata);
1101 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1102 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1103 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1104 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1105 uint32_t inf_max_rt = ntohl_unaligned(odata);
1106 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1107 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1108 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1109 #ifdef EXT_CER_ID
1110 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1111 sizeof(struct dhcpv6_cer_id)) {
1112 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1113 struct in6_addr any = IN6ADDR_ANY_INIT;
1114 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1115 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1116 #endif
1117 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1118 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1119 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1120 size_t mape_len;
1121 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1122 if (mape_len == 0)
1123 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1124 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1125 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1126 } else
1127 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1128
1129 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1130 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1131 }
1132 }
1133
1134 switch (orig) {
1135 case DHCPV6_MSG_REQUEST:
1136 case DHCPV6_MSG_REBIND:
1137 case DHCPV6_MSG_RENEW:
1138 // Update refresh timers if no fatal status code was received
1139 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1140 if (orig == DHCPV6_MSG_REQUEST) {
1141 // All server candidates can be cleared if not yet bound
1142 if (!odhcp6c_is_bound())
1143 dhcpv6_clear_all_server_cand();
1144
1145 odhcp6c_clear_state(STATE_SERVER_ADDR);
1146 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1147 } else if (orig == DHCPV6_MSG_RENEW) {
1148 // Send further renews if T1 is not set
1149 if (!t1)
1150 ret = -1;
1151
1152 } else if (orig == DHCPV6_MSG_REBIND) {
1153 // Send further rebinds if T1 and T2 is not set
1154 if (!t1 && !t2)
1155 ret = -1;
1156
1157 odhcp6c_clear_state(STATE_SERVER_ADDR);
1158 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1159 }
1160 }
1161 break;
1162
1163 case DHCPV6_MSG_INFO_REQ:
1164 if (ret > 0) {
1165 // All server candidates can be cleared if not yet bound
1166 if (!odhcp6c_is_bound())
1167 dhcpv6_clear_all_server_cand();
1168
1169 t1 = refresh;
1170 }
1171 break;
1172
1173 default:
1174 break;
1175 }
1176
1177 return ret;
1178 }
1179
1180 static int dhcpv6_parse_ia(void *opt, void *end)
1181 {
1182 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1183 int parsed_ia = 0;
1184 uint32_t t1, t2;
1185 uint16_t otype, olen;
1186 uint8_t *odata;
1187
1188 t1 = ntohl(ia_hdr->t1);
1189 t2 = ntohl(ia_hdr->t2);
1190
1191 if (t1 > t2)
1192 return 0;
1193
1194 // Update address IA
1195 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1196 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1197 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1198
1199 entry.iaid = ia_hdr->iaid;
1200
1201 if (otype == DHCPV6_OPT_IA_PREFIX) {
1202 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1203 if (olen + 4U < sizeof(*prefix))
1204 continue;
1205
1206 entry.valid = ntohl(prefix->valid);
1207 entry.preferred = ntohl(prefix->preferred);
1208
1209 if (entry.preferred > entry.valid)
1210 continue;
1211
1212 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1213 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1214 if (entry.t1 > entry.t2)
1215 entry.t1 = entry.t2;
1216
1217 entry.length = prefix->prefix;
1218 entry.target = prefix->addr;
1219 uint16_t stype, slen;
1220 uint8_t *sdata;
1221
1222 // Parse PD-exclude
1223 bool ok = true;
1224 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1225 odata + olen, stype, slen, sdata) {
1226 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1227 continue;
1228
1229 uint8_t elen = sdata[0];
1230 if (elen > 64)
1231 elen = 64;
1232
1233 if (entry.length < 32 || elen <= entry.length) {
1234 ok = false;
1235 continue;
1236 }
1237
1238 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1239 if (slen <= bytes) {
1240 ok = false;
1241 continue;
1242 }
1243
1244 uint32_t exclude = 0;
1245 do {
1246 exclude = exclude << 8 | sdata[bytes];
1247 } while (--bytes);
1248
1249 exclude >>= 8 - ((elen - entry.length) % 8);
1250 exclude <<= 64 - elen;
1251
1252 // Abusing router & priority fields for exclusion
1253 entry.router = entry.target;
1254 entry.router.s6_addr32[1] |= htonl(exclude);
1255 entry.priority = elen;
1256 }
1257
1258 if (ok) {
1259 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0);
1260 parsed_ia++;
1261 }
1262
1263 entry.priority = 0;
1264 memset(&entry.router, 0, sizeof(entry.router));
1265 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1266 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1267 if (olen + 4U < sizeof(*addr))
1268 continue;
1269
1270 entry.preferred = ntohl(addr->preferred);
1271 entry.valid = ntohl(addr->valid);
1272
1273 if (entry.preferred > entry.valid)
1274 continue;
1275
1276 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1277 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1278 if (entry.t1 > entry.t2)
1279 entry.t1 = entry.t2;
1280
1281 entry.length = 128;
1282 entry.target = addr->addr;
1283
1284 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0);
1285 parsed_ia++;
1286 }
1287 }
1288 return parsed_ia;
1289 }
1290
1291 static int dhcpv6_calc_refresh_timers(void)
1292 {
1293 struct odhcp6c_entry *e;
1294 size_t ia_na_entries, ia_pd_entries, i;
1295 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1296
1297 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1298 ia_na_entries /= sizeof(*e);
1299
1300 for (i = 0; i < ia_na_entries; i++) {
1301 if (e[i].t1 < l_t1)
1302 l_t1 = e[i].t1;
1303
1304 if (e[i].t2 < l_t2)
1305 l_t2 = e[i].t2;
1306
1307 if (e[i].valid > l_t3)
1308 l_t3 = e[i].valid;
1309 }
1310
1311 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1312 ia_pd_entries /= sizeof(*e);
1313
1314 for (i = 0; i < ia_pd_entries; i++) {
1315 if (e[i].t1 < l_t1)
1316 l_t1 = e[i].t1;
1317
1318 if (e[i].t2 < l_t2)
1319 l_t2 = e[i].t2;
1320
1321 if (e[i].valid > l_t3)
1322 l_t3 = e[i].valid;
1323 }
1324
1325 if (ia_pd_entries || ia_na_entries) {
1326 t1 = l_t1;
1327 t2 = l_t2;
1328 t3 = l_t3;
1329 }
1330
1331 return (int)(ia_pd_entries + ia_na_entries);
1332 }
1333
1334 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1335 const void *status_msg, int len)
1336 {
1337 const char *src = status_msg;
1338 char buf[len + 3];
1339 char *dst = buf;
1340
1341 if (len) {
1342 *dst++ = '(';
1343 while (len--) {
1344 *dst = isprint((unsigned char)*src) ? *src : '?';
1345 src++;
1346 dst++;
1347 }
1348 *dst++ = ')';
1349 }
1350
1351 *dst = 0;
1352
1353 syslog(LOG_WARNING, "Server returned %s status %i %s",
1354 scope, code, buf);
1355 }
1356
1357 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1358 const uint16_t code, const void *status_msg, const int len,
1359 int *ret)
1360 {
1361 dhcpv6_log_status_code(code, "message", status_msg, len);
1362
1363 switch (code) {
1364 case DHCPV6_UnspecFail:
1365 // Generic failure
1366 *ret = 0;
1367 break;
1368
1369 case DHCPV6_UseMulticast:
1370 switch(orig) {
1371 case DHCPV6_MSG_REQUEST:
1372 case DHCPV6_MSG_RENEW:
1373 case DHCPV6_MSG_RELEASE:
1374 case DHCPV6_MSG_DECLINE:
1375 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1376 server_addr = in6addr_any;
1377 *ret = 0;
1378 break;
1379 default:
1380 break;
1381 }
1382 break;
1383
1384 case DHCPV6_NoAddrsAvail:
1385 case DHCPV6_NoPrefixAvail:
1386 if (orig == DHCPV6_MSG_REQUEST)
1387 *ret = 0; // Failure
1388 break;
1389
1390 default:
1391 break;
1392 }
1393 }
1394
1395 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1396 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1397 const void *status_msg, const int len,
1398 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1399 {
1400 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1401 "IA_NA" : "IA_PD", status_msg, len);
1402
1403 switch (code) {
1404 case DHCPV6_NoBinding:
1405 switch (orig) {
1406 case DHCPV6_MSG_RENEW:
1407 case DHCPV6_MSG_REBIND:
1408 if ((*ret > 0) && !handled_status_codes[code])
1409 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1410 break;
1411
1412 default:
1413 break;
1414 }
1415 break;
1416
1417 default:
1418 *ret = 0;
1419 break;
1420 }
1421 }
1422
1423 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1424 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1425 {
1426 size_t cand_len, i;
1427 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1428
1429 // Remove identical duid server candidate
1430 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1431 if (cand->duid_len == c[i].duid_len &&
1432 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1433 free(c[i].ia_na);
1434 free(c[i].ia_pd);
1435 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1436 break;
1437 }
1438 }
1439
1440 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1441 i < cand_len / sizeof(*c); ++i) {
1442 if (c[i].preference < cand->preference)
1443 break;
1444 }
1445
1446 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1447 free(cand->ia_na);
1448 free(cand->ia_pd);
1449 }
1450 }
1451
1452 static void dhcpv6_clear_all_server_cand(void)
1453 {
1454 size_t cand_len, i;
1455 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1456
1457 // Server candidates need deep delete for IA_NA/IA_PD
1458 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1459 free(c[i].ia_na);
1460 free(c[i].ia_pd);
1461 }
1462 odhcp6c_clear_state(STATE_SERVER_CAND);
1463 }
1464
1465 int dhcpv6_promote_server_cand(void)
1466 {
1467 size_t cand_len;
1468 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1469 uint16_t hdr[2];
1470 int ret = DHCPV6_STATELESS;
1471
1472 // Clear lingering candidate state info
1473 odhcp6c_clear_state(STATE_SERVER_ID);
1474 odhcp6c_clear_state(STATE_IA_NA);
1475 odhcp6c_clear_state(STATE_IA_PD);
1476
1477 if (!cand_len)
1478 return -1;
1479
1480 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1481 na_mode = IA_MODE_NONE;
1482
1483 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1484 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1485
1486 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1487 }
1488
1489 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1490 hdr[1] = htons(cand->duid_len);
1491 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1492 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1493 accept_reconfig = cand->wants_reconfigure;
1494
1495 if (cand->ia_na_len) {
1496 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1497 free(cand->ia_na);
1498 if (na_mode != IA_MODE_NONE)
1499 ret = DHCPV6_STATEFUL;
1500 }
1501
1502 if (cand->ia_pd_len) {
1503 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1504 free(cand->ia_pd);
1505 if (request_prefix)
1506 ret = DHCPV6_STATEFUL;
1507 }
1508
1509 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1510 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1511
1512 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1513
1514 return ret;
1515 }
Openwrt DHCPv6 Client