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