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Avoid solicit for zero-length prefix
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15 #include <time.h>
16 #include <fcntl.h>
17 #include <errno.h>
18 #include <stdlib.h>
19 #include <signal.h>
20 #include <limits.h>
21 #include <resolv.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <syslog.h>
25 #include <stdbool.h>
26 #include <sys/time.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30
31 #include <net/if.h>
32 #include <net/ethernet.h>
33
34 #include "odhcp6c.h"
35 #include "md5.h"
36
37
38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
39 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
40 #define DHCPV6_CLIENT_PORT 546
41 #define DHCPV6_SERVER_PORT 547
42 #define DHCPV6_DUID_LLADDR 3
43 #define DHCPV6_REQ_DELAY 1
44
45 #define DHCPV6_SOL_MAX_RT_MIN 60
46 #define DHCPV6_SOL_MAX_RT_MAX 86400
47 #define DHCPV6_INF_MAX_RT_MIN 60
48 #define DHCPV6_INF_MAX_RT_MAX 86400
49
50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
51 const uint8_t transaction[3], enum dhcpv6_msg type,
52 const struct in6_addr *daddr);
53
54 static int dhcpv6_parse_ia(void *opt, void *end);
55
56 static int dhcpv6_calc_refresh_timers(void);
57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
58 const uint16_t code, const void *status_msg, const int len,
59 int *ret);
60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
61 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
62 const void *status_msg, const int len,
63 bool handled_status_codes[_DHCPV6_Status_Max],
64 int *ret);
65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
66 static void dhcpv6_clear_all_server_cand(void);
67
68 static reply_handler dhcpv6_handle_reply;
69 static reply_handler dhcpv6_handle_advert;
70 static reply_handler dhcpv6_handle_rebind_reply;
71 static reply_handler dhcpv6_handle_reconfigure;
72 static int dhcpv6_commit_advert(void);
73
74
75
76 // RFC 3315 - 5.5 Timeout and Delay values
77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
78 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
79 dhcpv6_handle_reconfigure, NULL},
80 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
81 dhcpv6_handle_advert, dhcpv6_commit_advert},
82 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
83 dhcpv6_handle_reply, NULL},
84 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
85 dhcpv6_handle_reply, NULL},
86 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
87 dhcpv6_handle_rebind_reply, NULL},
88 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
89 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
90 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
91 dhcpv6_handle_reply, NULL},
92 };
93
94
95 // Sockets
96 static int sock = -1;
97 static int ifindex = -1;
98 static int64_t t1 = 0, t2 = 0, t3 = 0;
99
100 // IA states
101 static int request_prefix = -1;
102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
103 static bool accept_reconfig = false;
104
105 // Reconfigure key
106 static uint8_t reconf_key[16];
107
108 // client options
109 static unsigned int client_options = 0;
110
111
112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
113 {
114 client_options = options;
115 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
116
117 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
118 if (sock < 0)
119 return -1;
120
121 // Detect interface
122 struct ifreq ifr;
123 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
124 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
125 return -1;
126 ifindex = ifr.ifr_ifindex;
127
128 // Create client DUID
129 size_t client_id_len;
130 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
131 if (client_id_len == 0) {
132 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
133 DHCPV6_DUID_LLADDR, 0, 1};
134
135 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
136 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
137
138 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
139 struct ifreq ifs[100], *ifp, *ifend;
140 struct ifconf ifc;
141 ifc.ifc_req = ifs;
142 ifc.ifc_len = sizeof(ifs);
143
144 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
145 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
146 // If our interface doesn't have an address...
147 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
148 for (ifp = ifc.ifc_req; ifp < ifend &&
149 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
150 memcpy(ifr.ifr_name, ifp->ifr_name,
151 sizeof(ifr.ifr_name));
152 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
153 continue;
154
155 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
156 ETHER_ADDR_LEN);
157 }
158 }
159
160 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
161 }
162
163 // Create ORO
164 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
165 uint16_t oro[] = {
166 htons(DHCPV6_OPT_SIP_SERVER_D),
167 htons(DHCPV6_OPT_SIP_SERVER_A),
168 htons(DHCPV6_OPT_DNS_SERVERS),
169 htons(DHCPV6_OPT_DNS_DOMAIN),
170 htons(DHCPV6_OPT_SNTP_SERVERS),
171 htons(DHCPV6_OPT_NTP_SERVER),
172 htons(DHCPV6_OPT_AFTR_NAME),
173 htons(DHCPV6_OPT_PD_EXCLUDE),
174 htons(DHCPV6_OPT_SOL_MAX_RT),
175 htons(DHCPV6_OPT_INF_MAX_RT),
176 #ifdef EXT_CER_ID
177 htons(DHCPV6_OPT_CER_ID),
178 #endif
179 htons(DHCPV6_OPT_S46_CONT_MAPE),
180 htons(DHCPV6_OPT_S46_CONT_MAPT),
181 htons(DHCPV6_OPT_S46_CONT_LW),
182 };
183 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
184 }
185
186 // Configure IPv6-options
187 int val = 1;
188 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
189 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
190 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
191 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
192
193 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
194 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
195 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
196 return -1;
197
198 return 0;
199 }
200
201 enum {
202 IOV_HDR=0,
203 IOV_ORO,
204 IOV_ORO_REFRESH,
205 IOV_CL_ID,
206 IOV_SRV_ID,
207 IOV_VENDOR_CLASS_HDR,
208 IOV_VENDOR_CLASS,
209 IOV_USER_CLASS_HDR,
210 IOV_USER_CLASS,
211 IOV_RECONF_ACCEPT,
212 IOV_FQDN,
213 IOV_HDR_IA_NA,
214 IOV_IA_NA,
215 IOV_IA_PD,
216 IOV_TOTAL
217 };
218
219 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
220 {
221 int mode = DHCPV6_UNKNOWN;
222
223 na_mode = na;
224 pd_mode = pd;
225
226 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
227 mode = DHCPV6_STATELESS;
228 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
229 mode = DHCPV6_STATEFUL;
230
231 return mode;
232 }
233
234 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
235 {
236 // Build FQDN
237 char fqdn_buf[256];
238 gethostname(fqdn_buf, sizeof(fqdn_buf));
239 struct {
240 uint16_t type;
241 uint16_t len;
242 uint8_t flags;
243 uint8_t data[256];
244 } fqdn;
245 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
246 sizeof(fqdn.data), NULL, NULL);
247 fqdn.type = htons(DHCPV6_OPT_FQDN);
248 fqdn.len = htons(fqdn_len - 4);
249 fqdn.flags = 0;
250
251
252 // Build Client ID
253 size_t cl_id_len;
254 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
255
256 // Get Server ID
257 size_t srv_id_len;
258 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
259
260 // Build IA_PDs
261 size_t ia_pd_entries = 0, ia_pd_len = 0;
262 uint8_t *ia_pd;
263
264 if (type == DHCPV6_MSG_SOLICIT) {
265 odhcp6c_clear_state(STATE_IA_PD);
266 size_t n_prefixes;
267 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
268 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
269
270 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
271
272 for (size_t i = 0; i < n_prefixes; i++) {
273 struct dhcpv6_ia_hdr hdr_ia_pd = {
274 htons(DHCPV6_OPT_IA_PD),
275 htons(sizeof(hdr_ia_pd) - 4 +
276 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
277 request_prefixes[i].iaid, 0, 0
278 };
279 struct dhcpv6_ia_prefix pref = {
280 .type = htons(DHCPV6_OPT_IA_PREFIX),
281 .len = htons(sizeof(pref) - 4),
282 .prefix = request_prefixes[i].length
283 };
284 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
285 ia_pd_len += sizeof(hdr_ia_pd);
286 if (request_prefixes[i].length) {
287 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
288 ia_pd_len += sizeof(pref);
289 }
290 }
291 } else {
292 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
293 ia_pd_entries /= sizeof(*e);
294
295 // we're too lazy to count our distinct IAIDs,
296 // so just allocate maximally needed space
297 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
298 sizeof(struct dhcpv6_ia_hdr)));
299
300 for (size_t i = 0; i < ia_pd_entries; ++i) {
301 uint32_t iaid = e[i].iaid;
302
303 // check if this is an unprocessed IAID and skip if not.
304 int new_iaid = 1;
305 for (int j = i-1; j >= 0; j--) {
306 if (e[j].iaid == iaid) {
307 new_iaid = 0;
308 break;
309 }
310 }
311
312 if (!new_iaid)
313 continue;
314
315 // construct header
316 struct dhcpv6_ia_hdr hdr_ia_pd = {
317 htons(DHCPV6_OPT_IA_PD),
318 htons(sizeof(hdr_ia_pd) - 4),
319 iaid, 0, 0
320 };
321
322 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
323 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
324 ia_pd_len += sizeof(hdr_ia_pd);
325
326 for (size_t j = i; j < ia_pd_entries; j++) {
327 if (e[j].iaid != iaid)
328 continue;
329
330 uint8_t ex_len = 0;
331 if (e[j].priority > 0)
332 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
333
334 struct dhcpv6_ia_prefix p = {
335 .type = htons(DHCPV6_OPT_IA_PREFIX),
336 .len = htons(sizeof(p) - 4U + ex_len),
337 .prefix = e[j].length,
338 .addr = e[j].target
339 };
340
341 if (type == DHCPV6_MSG_REQUEST) {
342 p.preferred = htonl(e[j].preferred);
343 p.valid = htonl(e[j].valid);
344 }
345
346 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
347 ia_pd_len += sizeof(p);
348
349 if (ex_len) {
350 ia_pd[ia_pd_len++] = 0;
351 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
352 ia_pd[ia_pd_len++] = 0;
353 ia_pd[ia_pd_len++] = ex_len - 4;
354 ia_pd[ia_pd_len++] = e[j].priority;
355
356 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
357 excl >>= (64 - e[j].priority);
358 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
359
360 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
361 ia_pd[ia_pd_len + i] = excl & 0xff;
362 ia_pd_len += ex_len - 5;
363 }
364
365 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
366 }
367 }
368 }
369
370 if (ia_pd_entries > 0)
371 request_prefix = 1;
372
373 // Build IA_NAs
374 size_t ia_na_entries, ia_na_len = 0;
375 void *ia_na = NULL;
376 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
377 ia_na_entries /= sizeof(*e);
378
379 struct dhcpv6_ia_hdr hdr_ia_na = {
380 htons(DHCPV6_OPT_IA_NA),
381 htons(sizeof(hdr_ia_na) - 4),
382 htonl(1), 0, 0
383 };
384
385 struct dhcpv6_ia_addr pa[ia_na_entries];
386 for (size_t i = 0; i < ia_na_entries; ++i) {
387 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
388 pa[i].len = htons(sizeof(pa[i]) - 4U);
389 pa[i].addr = e[i].target;
390
391 if (type == DHCPV6_MSG_REQUEST) {
392 pa[i].preferred = htonl(e[i].preferred);
393 pa[i].valid = htonl(e[i].valid);
394 } else {
395 pa[i].preferred = 0;
396 pa[i].valid = 0;
397 }
398 }
399
400 ia_na = pa;
401 ia_na_len = sizeof(pa);
402 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
403
404 // Reconfigure Accept
405 struct {
406 uint16_t type;
407 uint16_t length;
408 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
409
410 // Request Information Refresh
411 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
412
413 // Build vendor-class option
414 size_t vendor_class_len, user_class_len;
415 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
416 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
417
418 struct {
419 uint16_t type;
420 uint16_t length;
421 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
422
423 struct {
424 uint16_t type;
425 uint16_t length;
426 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
427
428 // Prepare Header
429 size_t oro_len;
430 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
431 struct {
432 uint8_t type;
433 uint8_t trid[3];
434 uint16_t elapsed_type;
435 uint16_t elapsed_len;
436 uint16_t elapsed_value;
437 uint16_t oro_type;
438 uint16_t oro_len;
439 } hdr = {
440 type, {trid[0], trid[1], trid[2]},
441 htons(DHCPV6_OPT_ELAPSED), htons(2),
442 htons((ecs > 0xffff) ? 0xffff : ecs),
443 htons(DHCPV6_OPT_ORO), htons(oro_len),
444 };
445
446 struct iovec iov[IOV_TOTAL] = {
447 [IOV_HDR] = {&hdr, sizeof(hdr)},
448 [IOV_ORO] = {oro, oro_len},
449 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
450 [IOV_CL_ID] = {cl_id, cl_id_len},
451 [IOV_SRV_ID] = {srv_id, srv_id_len},
452 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
453 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
454 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
455 [IOV_USER_CLASS] = {user_class, user_class_len},
456 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
457 [IOV_FQDN] = {&fqdn, fqdn_len},
458 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
459 [IOV_IA_NA] = {ia_na, ia_na_len},
460 [IOV_IA_PD] = {ia_pd, ia_pd_len},
461 };
462
463 size_t cnt = IOV_TOTAL;
464 if (type == DHCPV6_MSG_INFO_REQ) {
465 cnt = 9;
466 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
467 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
468 } else if (!request_prefix) {
469 cnt = 13;
470 }
471
472 // Disable IAs if not used
473 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
474 iov[IOV_HDR_IA_NA].iov_len = 0;
475
476 if (na_mode == IA_MODE_NONE)
477 iov[IOV_HDR_IA_NA].iov_len = 0;
478
479 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
480 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
481 iov[IOV_RECONF_ACCEPT].iov_len = 0;
482
483 if (!(client_options & DHCPV6_CLIENT_FQDN))
484 iov[IOV_FQDN].iov_len = 0;
485
486 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
487 0, ALL_DHCPV6_RELAYS, ifindex};
488 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
489 .msg_iov = iov, .msg_iovlen = cnt};
490
491 sendmsg(sock, &msg, 0);
492 }
493
494
495 static int64_t dhcpv6_rand_delay(int64_t time)
496 {
497 int random;
498 odhcp6c_random(&random, sizeof(random));
499 return (time * ((int64_t)random % 1000LL)) / 10000LL;
500 }
501
502
503 int dhcpv6_request(enum dhcpv6_msg type)
504 {
505 uint8_t rc = 0;
506 uint64_t timeout = UINT32_MAX;
507 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
508
509 if (retx->delay) {
510 struct timespec ts = {0, 0};
511 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
512 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
513 }
514
515 if (type == DHCPV6_MSG_UNKNOWN)
516 timeout = t1;
517 else if (type == DHCPV6_MSG_RENEW)
518 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
519 else if (type == DHCPV6_MSG_REBIND)
520 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
521
522 if (timeout == 0)
523 return -1;
524
525 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
526 retx->name, (unsigned long long)timeout, retx->max_rc);
527
528 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
529
530 // Generate transaction ID
531 uint8_t trid[3] = {0, 0, 0};
532 if (type != DHCPV6_MSG_UNKNOWN)
533 odhcp6c_random(trid, sizeof(trid));
534 ssize_t len = -1;
535 int64_t rto = 0;
536
537 do {
538 if (rto == 0) {
539 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
540
541 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
542 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
543 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
544
545 rto = (retx->init_timeo * 1000 + delay);
546 }
547 else
548 rto = (2 * rto + dhcpv6_rand_delay(rto));
549
550 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
551 rto = retx->max_timeo * 1000 +
552 dhcpv6_rand_delay(retx->max_timeo * 1000);
553
554 // Calculate end for this round and elapsed time
555 uint64_t round_end = round_start + rto;
556 elapsed = round_start - start;
557
558 // Don't wait too long if timeout differs from infinite
559 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
560 round_end = timeout * 1000 + start;
561
562 // Built and send package
563 switch (type) {
564 case DHCPV6_MSG_UNKNOWN:
565 break;
566 default:
567 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
568 retx->name, (unsigned long long)elapsed, rc);
569 // Fall through
570 case DHCPV6_MSG_SOLICIT:
571 case DHCPV6_MSG_INFO_REQ:
572 dhcpv6_send(type, trid, elapsed / 10);
573 rc++;
574 }
575
576 // Receive rounds
577 for (; len < 0 && (round_start < round_end);
578 round_start = odhcp6c_get_milli_time()) {
579 uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
580 struct iovec iov = {buf, sizeof(buf)};
581 struct sockaddr_in6 addr;
582 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
583 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
584 .msg_controllen = sizeof(cmsg_buf)};
585 struct in6_pktinfo *pktinfo = NULL;
586
587
588 // Check for pending signal
589 if (odhcp6c_signal_process())
590 return -1;
591
592 // Set timeout for receiving
593 uint64_t t = round_end - round_start;
594 struct timeval tv = {t / 1000, (t % 1000) * 1000};
595 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
596 &tv, sizeof(tv));
597
598 // Receive cycle
599 len = recvmsg(sock, &msg, 0);
600 if (len < 0)
601 continue;
602
603 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
604 ch = CMSG_NXTHDR(&msg, ch)) {
605 if (ch->cmsg_level == SOL_IPV6 &&
606 ch->cmsg_type == IPV6_PKTINFO) {
607 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
608 break;
609 }
610 }
611
612 if (pktinfo == NULL) {
613 len = -1;
614 continue;
615 }
616
617 if (!dhcpv6_response_is_valid(buf, len, trid,
618 type, &pktinfo->ipi6_addr)) {
619 len = -1;
620 continue;
621 }
622
623 uint8_t *opt = &buf[4];
624 uint8_t *opt_end = opt + len - 4;
625
626 round_start = odhcp6c_get_milli_time();
627 elapsed = round_start - start;
628 syslog(LOG_NOTICE, "Got a valid reply after "
629 "%llums", (unsigned long long)elapsed);
630
631 if (retx->handler_reply)
632 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
633
634 if (len > 0 && round_end - round_start > 1000)
635 round_end = 1000 + round_start;
636 }
637
638 // Allow
639 if (retx->handler_finish)
640 len = retx->handler_finish();
641 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
642 (!retx->max_rc || rc < retx->max_rc));
643 return len;
644 }
645
646 // Message validation checks according to RFC3315 chapter 15
647 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
648 const uint8_t transaction[3], enum dhcpv6_msg type,
649 const struct in6_addr *daddr)
650 {
651 const struct dhcpv6_header *rep = buf;
652 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
653 transaction, sizeof(rep->tr_id)))
654 return false; // Invalid reply
655
656 if (type == DHCPV6_MSG_SOLICIT) {
657 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
658 rep->msg_type != DHCPV6_MSG_REPLY)
659 return false;
660 } else if (type == DHCPV6_MSG_UNKNOWN) {
661 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
662 return false;
663 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
664 return false;
665 }
666
667 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
668 rcmsg = DHCPV6_MSG_UNKNOWN;
669 uint16_t otype, olen = UINT16_MAX;
670 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
671 ia_present = false, options_valid = true;
672
673 size_t client_id_len, server_id_len;
674 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
675 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
676
677 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
678 if (otype == DHCPV6_OPT_CLIENTID) {
679 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
680 &odata[-4], client_id, client_id_len);
681 } else if (otype == DHCPV6_OPT_SERVERID) {
682 if (server_id_len)
683 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
684 &odata[-4], server_id, server_id_len);
685 else
686 serverid_ok = true;
687 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
688 sizeof(struct dhcpv6_auth_reconfigure)) {
689 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
690 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
691 continue;
692
693 md5_ctx_t md5;
694 uint8_t serverhash[16], secretbytes[64], hash[16];
695 memcpy(serverhash, r->key, sizeof(serverhash));
696 memset(r->key, 0, sizeof(r->key));
697
698 memset(secretbytes, 0, sizeof(secretbytes));
699 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
700
701 for (size_t i = 0; i < sizeof(secretbytes); ++i)
702 secretbytes[i] ^= 0x36;
703
704 md5_begin(&md5);
705 md5_hash(secretbytes, sizeof(secretbytes), &md5);
706 md5_hash(buf, len, &md5);
707 md5_end(hash, &md5);
708
709 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
710 secretbytes[i] ^= 0x36;
711 secretbytes[i] ^= 0x5c;
712 }
713
714 md5_begin(&md5);
715 md5_hash(secretbytes, sizeof(secretbytes), &md5);
716 md5_hash(hash, 16, &md5);
717 md5_end(hash, &md5);
718
719 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
720 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
721 rcmsg = odata[0];
722 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
723 ia_present = true;
724 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
725 options_valid = false;
726 }
727 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
728 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
729 // Options are not allowed on global level
730 options_valid = false;
731 }
732 }
733
734 if (!options_valid || ((odata + olen) > end))
735 return false;
736
737 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
738 return false;
739
740 if (rep->msg_type == DHCPV6_MSG_RECONF) {
741 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
742 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
743 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
744 return false;
745 }
746
747 return clientid_ok && serverid_ok;
748 }
749
750
751 int dhcpv6_poll_reconfigure(void)
752 {
753 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
754 if (ret != -1)
755 ret = dhcpv6_request(ret);
756
757 return ret;
758 }
759
760
761 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
762 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
763 {
764 uint16_t otype, olen;
765 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
766 dhcpv6_for_each_option(opt, end, otype, olen, odata)
767 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
768 odata[0] == DHCPV6_MSG_RENEW ||
769 odata[0] == DHCPV6_MSG_INFO_REQ))
770 msg = odata[0];
771
772 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
773 return msg;
774 }
775
776
777 // Collect all advertised servers
778 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
779 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
780 {
781 uint16_t olen, otype;
782 uint8_t *odata, pref = 0;
783 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
784 DHCPV6_SOL_MAX_RT,
785 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
786 bool have_na = false;
787 int have_pd = 0;
788
789 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
790 if (orig == DHCPV6_MSG_SOLICIT &&
791 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
792 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
793 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
794 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
795 }
796
797 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
798 memcpy(cand.duid, odata, olen);
799 cand.duid_len = olen;
800 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
801 int error = ((int)odata[0] << 8 | (int)odata[1]);
802
803 switch (error) {
804 case DHCPV6_NoPrefixAvail:
805 // Status code on global level
806 cand.preference -= 2000;
807 break;
808
809 default :
810 break;
811 }
812 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
813 cand.preference >= 0) {
814 cand.preference = pref = odata[0];
815 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
816 cand.wants_reconfigure = true;
817 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
818 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
819 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
820 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
821 cand.sol_max_rt = sol_max_rt;
822 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
823 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
824 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
825 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
826 cand.inf_max_rt = inf_max_rt;
827 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
828 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
829 uint8_t *oend = odata + olen, *d;
830 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
831 if (otype == DHCPV6_OPT_IA_PREFIX &&
832 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
833 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
834 have_pd = p->prefix;
835 }
836 }
837 } else if (otype == DHCPV6_OPT_IA_NA) {
838 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
839 uint8_t *oend = odata + olen, *d;
840 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
841 if (otype == DHCPV6_OPT_IA_ADDR &&
842 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
843 have_na = true;
844 }
845 }
846
847 if ((!have_na && na_mode == IA_MODE_FORCE) ||
848 (!have_pd && pd_mode == IA_MODE_FORCE)) {
849 /*
850 * RFC7083 states to process the SOL_MAX_RT and
851 * INF_MAX_RT options even if the DHCPv6 server
852 * did not propose any IA_NA and/or IA_PD
853 */
854 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
855 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
856 return -1;
857 }
858
859 if (na_mode != IA_MODE_NONE && !have_na) {
860 cand.has_noaddravail = true;
861 cand.preference -= 1000;
862 }
863
864 if (pd_mode != IA_MODE_NONE) {
865 if (have_pd)
866 cand.preference += 2000 + (128 - have_pd);
867 else
868 cand.preference -= 2000;
869 }
870
871 if (cand.duid_len > 0) {
872 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
873 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
874 dhcpv6_add_server_cand(&cand);
875 }
876
877 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
878 }
879
880
881 static int dhcpv6_commit_advert(void)
882 {
883 return dhcpv6_promote_server_cand();
884 }
885
886
887 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
888 const void *opt, const void *end, const struct sockaddr_in6 *from)
889 {
890 dhcpv6_handle_advert(orig, rc, opt, end, from);
891 if (dhcpv6_commit_advert() < 0)
892 return -1;
893
894 return dhcpv6_handle_reply(orig, rc, opt, end, from);
895 }
896
897
898 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
899 const void *opt, const void *end, const struct sockaddr_in6 *from)
900 {
901 uint8_t *odata;
902 uint16_t otype, olen;
903 uint32_t refresh = 86400;
904 int ret = 1;
905 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
906
907 odhcp6c_expire();
908
909 if (orig == DHCPV6_MSG_UNKNOWN) {
910 static time_t last_update = 0;
911 time_t now = odhcp6c_get_milli_time() / 1000;
912
913 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
914 last_update = now;
915
916 if (t1 != UINT32_MAX)
917 t1 -= elapsed;
918
919 if (t2 != UINT32_MAX)
920 t2 -= elapsed;
921
922 if (t3 != UINT32_MAX)
923 t3 -= elapsed;
924
925 if (t1 < 0)
926 t1 = 0;
927
928 if (t2 < 0)
929 t2 = 0;
930
931 if (t3 < 0)
932 t3 = 0;
933 }
934
935 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
936 // Delete NA and PD we have in the state from the Advert
937 odhcp6c_clear_state(STATE_IA_NA);
938 odhcp6c_clear_state(STATE_IA_PD);
939 }
940
941 if (opt) {
942 odhcp6c_clear_state(STATE_DNS);
943 odhcp6c_clear_state(STATE_SEARCH);
944 odhcp6c_clear_state(STATE_SNTP_IP);
945 odhcp6c_clear_state(STATE_NTP_IP);
946 odhcp6c_clear_state(STATE_NTP_FQDN);
947 odhcp6c_clear_state(STATE_SIP_IP);
948 odhcp6c_clear_state(STATE_SIP_FQDN);
949 odhcp6c_clear_state(STATE_AFTR_NAME);
950 odhcp6c_clear_state(STATE_CER);
951 odhcp6c_clear_state(STATE_S46_MAPT);
952 odhcp6c_clear_state(STATE_S46_MAPE);
953 odhcp6c_clear_state(STATE_S46_LW);
954 odhcp6c_clear_state(STATE_PASSTHRU);
955 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
956
957 // Parse and find all matching IAs
958 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
959 bool passthru = true;
960
961 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
962 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
963 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
964
965 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
966 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
967 continue;
968
969 // Test ID
970 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
971 continue;
972
973 uint16_t code = DHCPV6_Success;
974 uint16_t stype, slen;
975 uint8_t *sdata;
976 // Get and handle status code
977 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
978 stype, slen, sdata) {
979 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
980 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
981 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
982
983 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
984
985 if (code == DHCPV6_Success)
986 continue;
987
988 dhcpv6_handle_ia_status_code(orig, ia_hdr,
989 code, mdata, mlen, handled_status_codes, &ret);
990
991
992 if (ret > 0)
993 return ret;
994 break;
995 }
996 }
997
998 if (code != DHCPV6_Success)
999 continue;
1000
1001 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
1002 passthru = false;
1003 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1004 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1005 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1006 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1007
1008 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1009 passthru = false;
1010 }
1011 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1012 if (olen % 16 == 0)
1013 odhcp6c_add_state(STATE_DNS, odata, olen);
1014 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1015 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1016 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1017 if (olen % 16 == 0)
1018 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1019 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1020 uint16_t stype, slen;
1021 uint8_t *sdata;
1022 // Test status and bail if error
1023 dhcpv6_for_each_option(odata, odata + olen,
1024 stype, slen, sdata) {
1025 if (slen == 16 && (stype == NTP_MC_ADDR ||
1026 stype == NTP_SRV_ADDR))
1027 odhcp6c_add_state(STATE_NTP_IP,
1028 sdata, slen);
1029 else if (slen > 0 && stype == NTP_SRV_FQDN)
1030 odhcp6c_add_state(STATE_NTP_FQDN,
1031 sdata, slen);
1032 }
1033 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1034 if (olen == 16)
1035 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1036 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1037 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1038 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1039 refresh = ntohl(*((uint32_t*)odata));
1040 passthru = false;
1041 } else if (otype == DHCPV6_OPT_AUTH) {
1042 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1043 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1044 if (r->protocol == 3 && r->algorithm == 1 &&
1045 r->reconf_type == 1)
1046 memcpy(reconf_key, r->key, sizeof(r->key));
1047 }
1048 passthru = false;
1049 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1050 size_t cur_len;
1051 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1052 if (cur_len == 0)
1053 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1054 passthru = false;
1055 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1056 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1057 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1058 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1059 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1060 passthru = false;
1061 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1062 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1063 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1064 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1065 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1066 passthru = false;
1067 #ifdef EXT_CER_ID
1068 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1069 sizeof(struct dhcpv6_cer_id)) {
1070 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1071 struct in6_addr any = IN6ADDR_ANY_INIT;
1072 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1073 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1074 passthru = false;
1075 #endif
1076 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1077 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1078 passthru = false;
1079 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1080 size_t mape_len;
1081 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1082 if (mape_len == 0)
1083 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1084 passthru = false;
1085 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1086 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1087 passthru = false;
1088 } else if (otype == DHCPV6_OPT_CLIENTID ||
1089 otype == DHCPV6_OPT_SERVERID ||
1090 otype == DHCPV6_OPT_IA_TA ||
1091 otype == DHCPV6_OPT_PREF ||
1092 otype == DHCPV6_OPT_UNICAST ||
1093 otype == DHCPV6_OPT_FQDN ||
1094 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1095 passthru = false;
1096 } else {
1097 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1098 }
1099
1100 if (passthru)
1101 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1102 }
1103 }
1104
1105 if (orig != DHCPV6_MSG_INFO_REQ) {
1106 // Update refresh timers if no fatal status code was received
1107 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1108 switch (orig) {
1109 case DHCPV6_MSG_RENEW:
1110 // Send further renews if T1 is not set
1111 if (!t1)
1112 ret = -1;
1113 break;
1114 case DHCPV6_MSG_REBIND:
1115 // Send further rebinds if T1 and T2 is not set
1116 if (!t1 && !t2)
1117 ret = -1;
1118 break;
1119
1120 case DHCPV6_MSG_REQUEST:
1121 // All server candidates can be cleared if not yet bound
1122 if (!odhcp6c_is_bound())
1123 dhcpv6_clear_all_server_cand();
1124
1125 default :
1126 break;
1127 }
1128
1129 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1130 odhcp6c_clear_state(STATE_SERVER_ADDR);
1131 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1132 }
1133 }
1134 }
1135 else if (ret > 0) {
1136 // All server candidates can be cleared if not yet bound
1137 if (!odhcp6c_is_bound())
1138 dhcpv6_clear_all_server_cand();
1139
1140 t1 = refresh;
1141 }
1142
1143 return ret;
1144 }
1145
1146
1147 static int dhcpv6_parse_ia(void *opt, void *end)
1148 {
1149 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1150 int parsed_ia = 0;
1151 uint32_t t1, t2;
1152 uint16_t otype, olen;
1153 uint8_t *odata;
1154
1155 t1 = ntohl(ia_hdr->t1);
1156 t2 = ntohl(ia_hdr->t2);
1157
1158 if (t1 > t2)
1159 return 0;
1160
1161 // Update address IA
1162 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1163 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1164 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1165
1166 entry.iaid = ia_hdr->iaid;
1167
1168 if (otype == DHCPV6_OPT_IA_PREFIX) {
1169 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1170 if (olen + 4U < sizeof(*prefix))
1171 continue;
1172
1173 entry.valid = ntohl(prefix->valid);
1174 entry.preferred = ntohl(prefix->preferred);
1175
1176 if (entry.preferred > entry.valid)
1177 continue;
1178
1179 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1180 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1181 if (entry.t1 > entry.t2)
1182 entry.t1 = entry.t2;
1183
1184 entry.length = prefix->prefix;
1185 entry.target = prefix->addr;
1186 uint16_t stype, slen;
1187 uint8_t *sdata;
1188
1189 // Parse PD-exclude
1190 bool ok = true;
1191 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1192 odata + olen, stype, slen, sdata) {
1193 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1194 continue;
1195
1196 uint8_t elen = sdata[0];
1197 if (elen > 64)
1198 elen = 64;
1199
1200 if (elen <= 32 || elen <= entry.length) {
1201 ok = false;
1202 continue;
1203 }
1204
1205
1206 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1207 if (slen <= bytes) {
1208 ok = false;
1209 continue;
1210 }
1211
1212 uint32_t exclude = 0;
1213 do {
1214 exclude = exclude << 8 | sdata[bytes];
1215 } while (--bytes);
1216
1217 exclude >>= 8 - ((elen - entry.length) % 8);
1218 exclude <<= 64 - elen;
1219
1220 // Abusing router & priority fields for exclusion
1221 entry.router = entry.target;
1222 entry.router.s6_addr32[1] |= htonl(exclude);
1223 entry.priority = elen;
1224 }
1225
1226 if (ok) {
1227 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1228 parsed_ia++;
1229 }
1230
1231 entry.priority = 0;
1232 memset(&entry.router, 0, sizeof(entry.router));
1233 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1234 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1235 if (olen + 4U < sizeof(*addr))
1236 continue;
1237
1238 entry.preferred = ntohl(addr->preferred);
1239 entry.valid = ntohl(addr->valid);
1240
1241 if (entry.preferred > entry.valid)
1242 continue;
1243
1244 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1245 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1246 if (entry.t1 > entry.t2)
1247 entry.t1 = entry.t2;
1248
1249 entry.length = 128;
1250 entry.target = addr->addr;
1251
1252 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1253 parsed_ia++;
1254 }
1255 }
1256 return parsed_ia;
1257 }
1258
1259
1260 static int dhcpv6_calc_refresh_timers(void)
1261 {
1262 struct odhcp6c_entry *e;
1263 size_t ia_na_entries, ia_pd_entries, i;
1264 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1265
1266 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1267 ia_na_entries /= sizeof(*e);
1268 for (i = 0; i < ia_na_entries; i++) {
1269 if (e[i].t1 < l_t1)
1270 l_t1 = e[i].t1;
1271
1272 if (e[i].t2 < l_t2)
1273 l_t2 = e[i].t2;
1274
1275 if (e[i].valid > l_t3)
1276 l_t3 = e[i].valid;
1277 }
1278
1279 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1280 ia_pd_entries /= sizeof(*e);
1281 for (i = 0; i < ia_pd_entries; i++) {
1282 if (e[i].t1 < l_t1)
1283 l_t1 = e[i].t1;
1284
1285 if (e[i].t2 < l_t2)
1286 l_t2 = e[i].t2;
1287
1288 if (e[i].valid > l_t3)
1289 l_t3 = e[i].valid;
1290 }
1291
1292 if (ia_pd_entries || ia_na_entries) {
1293 t1 = l_t1;
1294 t2 = l_t2;
1295 t3 = l_t3;
1296 } else {
1297 t1 = 600;
1298 }
1299
1300 return (int)(ia_pd_entries + ia_na_entries);
1301 }
1302
1303
1304 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1305 const void *status_msg, const int len)
1306 {
1307 uint8_t buf[len + 3];
1308
1309 memset(buf, 0, sizeof(buf));
1310 if (len) {
1311 buf[0] = '(';
1312 memcpy(&buf[1], status_msg, len);
1313 buf[len + 1] = ')';
1314 }
1315
1316 syslog(LOG_WARNING, "Server returned %s status %i %s",
1317 scope, code, buf);
1318 }
1319
1320
1321 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1322 const uint16_t code, const void *status_msg, const int len,
1323 int *ret)
1324 {
1325 dhcpv6_log_status_code(code, "message", status_msg, len);
1326
1327 switch (code) {
1328 case DHCPV6_UnspecFail:
1329 // Generic failure
1330 *ret = 0;
1331 break;
1332
1333 case DHCPV6_UseMulticast:
1334 // TODO handle multicast status code
1335 break;
1336
1337 case DHCPV6_NoAddrsAvail:
1338 case DHCPV6_NoPrefixAvail:
1339 if (orig == DHCPV6_MSG_REQUEST)
1340 *ret = 0; // Failure
1341 break;
1342
1343 default:
1344 break;
1345 }
1346 }
1347
1348
1349 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1350 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1351 const void *status_msg, const int len,
1352 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1353 {
1354 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1355 "IA_NA" : "IA_PD", status_msg, len);
1356
1357 switch (code) {
1358 case DHCPV6_NoBinding:
1359 switch (orig) {
1360 case DHCPV6_MSG_RENEW:
1361 case DHCPV6_MSG_REBIND:
1362 if ((*ret > 0) && !handled_status_codes[code])
1363 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1364 break;
1365
1366 default:
1367 break;
1368 }
1369 break;
1370
1371 default:
1372 *ret = 0;
1373 break;
1374 }
1375 }
1376
1377 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1378 {
1379 size_t cand_len, i;
1380 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1381
1382 // Remove identical duid server candidate
1383 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1384 if (cand->duid_len == c[i].duid_len &&
1385 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1386 free(c[i].ia_na);
1387 free(c[i].ia_pd);
1388 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1389 break;
1390 }
1391 }
1392
1393 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1394 i < cand_len / sizeof(*c); ++i) {
1395 if (c[i].preference < cand->preference)
1396 break;
1397 }
1398
1399 odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1400 }
1401
1402 static void dhcpv6_clear_all_server_cand(void)
1403 {
1404 size_t cand_len, i;
1405 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1406
1407 // Server candidates need deep delete for IA_NA/IA_PD
1408 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1409 free(c[i].ia_na);
1410 free(c[i].ia_pd);
1411 }
1412 odhcp6c_clear_state(STATE_SERVER_CAND);
1413 }
1414
1415 int dhcpv6_promote_server_cand(void)
1416 {
1417 size_t cand_len;
1418 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1419 uint16_t hdr[2];
1420 int ret = DHCPV6_STATELESS;
1421
1422 // Clear lingering candidate state info
1423 odhcp6c_clear_state(STATE_SERVER_ID);
1424 odhcp6c_clear_state(STATE_IA_NA);
1425 odhcp6c_clear_state(STATE_IA_PD);
1426
1427 if (!cand_len)
1428 return -1;
1429
1430 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1431 na_mode = IA_MODE_NONE;
1432
1433 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1434 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1435
1436 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1437 }
1438
1439 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1440 hdr[1] = htons(cand->duid_len);
1441 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1442 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1443 accept_reconfig = cand->wants_reconfigure;
1444 if (cand->ia_na_len) {
1445 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1446 free(cand->ia_na);
1447 if (na_mode != IA_MODE_NONE)
1448 ret = DHCPV6_STATEFUL;
1449 }
1450 if (cand->ia_pd_len) {
1451 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1452 free(cand->ia_pd);
1453 if (request_prefix)
1454 ret = DHCPV6_STATEFUL;
1455 }
1456
1457 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1458 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1459
1460 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1461
1462 return ret;
1463 }
Openwrt DHCPv6 Client