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dhcpv6: server unicast option support
[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 <ctype.h>
27 #include <sys/time.h>
28 #include <sys/ioctl.h>
29 #include <sys/socket.h>
30 #include <arpa/inet.h>
31 #include <netinet/in.h>
32
33 #include <net/if.h>
34 #include <net/ethernet.h>
35
36 #include "odhcp6c.h"
37 #ifdef LIBUBOX
38 #include <libubox/md5.h>
39 #else
40 #include "md5.h"
41 #endif
42
43
44 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
45 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
46 #define DHCPV6_CLIENT_PORT 546
47 #define DHCPV6_SERVER_PORT 547
48 #define DHCPV6_DUID_LLADDR 3
49 #define DHCPV6_REQ_DELAY 1
50
51 #define DHCPV6_SOL_MAX_RT_MIN 60
52 #define DHCPV6_SOL_MAX_RT_MAX 86400
53 #define DHCPV6_INF_MAX_RT_MIN 60
54 #define DHCPV6_INF_MAX_RT_MAX 86400
55
56 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
57 const uint8_t transaction[3], enum dhcpv6_msg type,
58 const struct in6_addr *daddr);
59
60 static int dhcpv6_parse_ia(void *opt, void *end);
61
62 static int dhcpv6_calc_refresh_timers(void);
63 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
64 const uint16_t code, const void *status_msg, const int len,
65 int *ret);
66 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
67 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
68 const void *status_msg, const int len,
69 bool handled_status_codes[_DHCPV6_Status_Max],
70 int *ret);
71 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
72 static void dhcpv6_clear_all_server_cand(void);
73
74 static reply_handler dhcpv6_handle_reply;
75 static reply_handler dhcpv6_handle_advert;
76 static reply_handler dhcpv6_handle_rebind_reply;
77 static reply_handler dhcpv6_handle_reconfigure;
78 static int dhcpv6_commit_advert(void);
79
80
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
101 // Sockets
102 static int sock = -1;
103 static int ifindex = -1;
104 static int64_t t1 = 0, t2 = 0, t3 = 0;
105
106 // IA states
107 static int request_prefix = -1;
108 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
109 static bool accept_reconfig = false;
110 // Server unicast address
111 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
112
113 // Reconfigure key
114 static uint8_t reconf_key[16];
115
116 // client options
117 static unsigned int client_options = 0;
118
119
120 static uint32_t ntohl_unaligned(const uint8_t *data)
121 {
122 uint32_t buf;
123
124 memcpy(&buf, data, sizeof(buf));
125 return ntohl(buf);
126 }
127
128 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
129 {
130 client_options = options;
131 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
132
133 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
134 if (sock < 0)
135 return -1;
136
137 // Detect interface
138 struct ifreq ifr;
139 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
140 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
141 return -1;
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 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
206 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
207 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
208 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
209
210 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
211 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
212 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
213 return -1;
214
215 return 0;
216 }
217
218 enum {
219 IOV_HDR=0,
220 IOV_ORO,
221 IOV_ORO_REFRESH,
222 IOV_CL_ID,
223 IOV_SRV_ID,
224 IOV_VENDOR_CLASS_HDR,
225 IOV_VENDOR_CLASS,
226 IOV_USER_CLASS_HDR,
227 IOV_USER_CLASS,
228 IOV_RECONF_ACCEPT,
229 IOV_FQDN,
230 IOV_HDR_IA_NA,
231 IOV_IA_NA,
232 IOV_IA_PD,
233 IOV_TOTAL
234 };
235
236 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
237 {
238 int mode = DHCPV6_UNKNOWN;
239
240 na_mode = na;
241 pd_mode = pd;
242
243 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
244 mode = DHCPV6_STATELESS;
245 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
246 mode = DHCPV6_STATEFUL;
247
248 return mode;
249 }
250
251 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
252 {
253 // Build FQDN
254 char fqdn_buf[256];
255 gethostname(fqdn_buf, sizeof(fqdn_buf));
256 struct {
257 uint16_t type;
258 uint16_t len;
259 uint8_t flags;
260 uint8_t data[256];
261 } fqdn;
262 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
263 sizeof(fqdn.data), NULL, NULL);
264 fqdn.type = htons(DHCPV6_OPT_FQDN);
265 fqdn.len = htons(fqdn_len - 4);
266 fqdn.flags = 0;
267
268
269 // Build Client ID
270 size_t cl_id_len;
271 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
272
273 // Get Server ID
274 size_t srv_id_len;
275 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
276
277 // Build IA_PDs
278 size_t ia_pd_entries = 0, ia_pd_len = 0;
279 uint8_t *ia_pd;
280
281 if (type == DHCPV6_MSG_SOLICIT) {
282 odhcp6c_clear_state(STATE_IA_PD);
283 size_t n_prefixes;
284 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
285 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
286
287 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
288
289 for (size_t i = 0; i < n_prefixes; i++) {
290 struct dhcpv6_ia_hdr hdr_ia_pd = {
291 htons(DHCPV6_OPT_IA_PD),
292 htons(sizeof(hdr_ia_pd) - 4 +
293 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
294 request_prefixes[i].iaid, 0, 0
295 };
296 struct dhcpv6_ia_prefix pref = {
297 .type = htons(DHCPV6_OPT_IA_PREFIX),
298 .len = htons(sizeof(pref) - 4),
299 .prefix = request_prefixes[i].length
300 };
301 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
302 ia_pd_len += sizeof(hdr_ia_pd);
303 if (request_prefixes[i].length) {
304 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
305 ia_pd_len += sizeof(pref);
306 }
307 }
308 } else {
309 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
310 ia_pd_entries /= sizeof(*e);
311
312 // we're too lazy to count our distinct IAIDs,
313 // so just allocate maximally needed space
314 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
315 sizeof(struct dhcpv6_ia_hdr)));
316
317 for (size_t i = 0; i < ia_pd_entries; ++i) {
318 uint32_t iaid = e[i].iaid;
319
320 // check if this is an unprocessed IAID and skip if not.
321 int new_iaid = 1;
322 for (int j = i-1; j >= 0; j--) {
323 if (e[j].iaid == iaid) {
324 new_iaid = 0;
325 break;
326 }
327 }
328
329 if (!new_iaid)
330 continue;
331
332 // construct header
333 struct dhcpv6_ia_hdr hdr_ia_pd = {
334 htons(DHCPV6_OPT_IA_PD),
335 htons(sizeof(hdr_ia_pd) - 4),
336 iaid, 0, 0
337 };
338
339 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
340 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
341 ia_pd_len += sizeof(hdr_ia_pd);
342
343 for (size_t j = i; j < ia_pd_entries; j++) {
344 if (e[j].iaid != iaid)
345 continue;
346
347 uint8_t ex_len = 0;
348 if (e[j].priority > 0)
349 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
350
351 struct dhcpv6_ia_prefix p = {
352 .type = htons(DHCPV6_OPT_IA_PREFIX),
353 .len = htons(sizeof(p) - 4U + ex_len),
354 .prefix = e[j].length,
355 .addr = e[j].target
356 };
357
358 if (type == DHCPV6_MSG_REQUEST) {
359 p.preferred = htonl(e[j].preferred);
360 p.valid = htonl(e[j].valid);
361 }
362
363 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
364 ia_pd_len += sizeof(p);
365
366 if (ex_len) {
367 ia_pd[ia_pd_len++] = 0;
368 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
369 ia_pd[ia_pd_len++] = 0;
370 ia_pd[ia_pd_len++] = ex_len - 4;
371 ia_pd[ia_pd_len++] = e[j].priority;
372
373 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
374 excl >>= (64 - e[j].priority);
375 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
376
377 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
378 ia_pd[ia_pd_len + i] = excl & 0xff;
379 ia_pd_len += ex_len - 5;
380 }
381
382 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
383 }
384 }
385 }
386
387 if (ia_pd_entries > 0)
388 request_prefix = 1;
389
390 // Build IA_NAs
391 size_t ia_na_entries, ia_na_len = 0;
392 void *ia_na = NULL;
393 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
394 ia_na_entries /= sizeof(*e);
395
396 struct dhcpv6_ia_hdr hdr_ia_na = {
397 htons(DHCPV6_OPT_IA_NA),
398 htons(sizeof(hdr_ia_na) - 4),
399 htonl(1), 0, 0
400 };
401
402 struct dhcpv6_ia_addr pa[ia_na_entries];
403 for (size_t i = 0; i < ia_na_entries; ++i) {
404 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
405 pa[i].len = htons(sizeof(pa[i]) - 4U);
406 pa[i].addr = e[i].target;
407
408 if (type == DHCPV6_MSG_REQUEST) {
409 pa[i].preferred = htonl(e[i].preferred);
410 pa[i].valid = htonl(e[i].valid);
411 } else {
412 pa[i].preferred = 0;
413 pa[i].valid = 0;
414 }
415 }
416
417 ia_na = pa;
418 ia_na_len = sizeof(pa);
419 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
420
421 // Reconfigure Accept
422 struct {
423 uint16_t type;
424 uint16_t length;
425 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
426
427 // Request Information Refresh
428 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
429
430 // Build vendor-class option
431 size_t vendor_class_len, user_class_len;
432 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
433 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
434
435 struct {
436 uint16_t type;
437 uint16_t length;
438 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
439
440 struct {
441 uint16_t type;
442 uint16_t length;
443 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
444
445 // Prepare Header
446 size_t oro_len;
447 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
448 struct {
449 uint8_t type;
450 uint8_t trid[3];
451 uint16_t elapsed_type;
452 uint16_t elapsed_len;
453 uint16_t elapsed_value;
454 uint16_t oro_type;
455 uint16_t oro_len;
456 } hdr = {
457 type, {trid[0], trid[1], trid[2]},
458 htons(DHCPV6_OPT_ELAPSED), htons(2),
459 htons((ecs > 0xffff) ? 0xffff : ecs),
460 htons(DHCPV6_OPT_ORO), htons(oro_len),
461 };
462
463 struct iovec iov[IOV_TOTAL] = {
464 [IOV_HDR] = {&hdr, sizeof(hdr)},
465 [IOV_ORO] = {oro, oro_len},
466 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
467 [IOV_CL_ID] = {cl_id, cl_id_len},
468 [IOV_SRV_ID] = {srv_id, srv_id_len},
469 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
470 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
471 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
472 [IOV_USER_CLASS] = {user_class, user_class_len},
473 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
474 [IOV_FQDN] = {&fqdn, fqdn_len},
475 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
476 [IOV_IA_NA] = {ia_na, ia_na_len},
477 [IOV_IA_PD] = {ia_pd, ia_pd_len},
478 };
479
480 size_t cnt = IOV_TOTAL;
481 if (type == DHCPV6_MSG_INFO_REQ) {
482 cnt = 9;
483 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
484 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
485 } else if (!request_prefix) {
486 cnt = 13;
487 }
488
489 // Disable IAs if not used
490 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
491 iov[IOV_HDR_IA_NA].iov_len = 0;
492
493 if (na_mode == IA_MODE_NONE)
494 iov[IOV_HDR_IA_NA].iov_len = 0;
495
496 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
497 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
498 iov[IOV_RECONF_ACCEPT].iov_len = 0;
499
500 if (!(client_options & DHCPV6_CLIENT_FQDN))
501 iov[IOV_FQDN].iov_len = 0;
502
503 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
504 0, ALL_DHCPV6_RELAYS, ifindex};
505 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
506 .msg_iov = iov, .msg_iovlen = cnt};
507
508 switch (type) {
509 case DHCPV6_MSG_REQUEST:
510 case DHCPV6_MSG_RENEW:
511 case DHCPV6_MSG_RELEASE:
512 case DHCPV6_MSG_DECLINE:
513 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
514 odhcp6c_addr_in_scope(&server_addr)) {
515 srv.sin6_addr = server_addr;
516 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
517 srv.sin6_scope_id = 0;
518 }
519 break;
520 default:
521 break;
522 }
523
524 if (sendmsg(sock, &msg, 0) < 0) {
525 char in6_str[INET6_ADDRSTRLEN];
526
527 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
528 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
529 in6_str, sizeof(in6_str)), strerror(errno));
530 }
531 }
532
533
534 static int64_t dhcpv6_rand_delay(int64_t time)
535 {
536 int random;
537 odhcp6c_random(&random, sizeof(random));
538 return (time * ((int64_t)random % 1000LL)) / 10000LL;
539 }
540
541
542 int dhcpv6_request(enum dhcpv6_msg type)
543 {
544 uint8_t rc = 0;
545 uint64_t timeout = UINT32_MAX;
546 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
547
548 if (retx->delay) {
549 struct timespec ts = {0, 0};
550 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
551 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
552 }
553
554 if (type == DHCPV6_MSG_UNKNOWN)
555 timeout = t1;
556 else if (type == DHCPV6_MSG_RENEW)
557 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
558 else if (type == DHCPV6_MSG_REBIND)
559 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
560
561 if (timeout == 0)
562 return -1;
563
564 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
565 retx->name, (unsigned long long)timeout, retx->max_rc);
566
567 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
568
569 // Generate transaction ID
570 uint8_t trid[3] = {0, 0, 0};
571 if (type != DHCPV6_MSG_UNKNOWN)
572 odhcp6c_random(trid, sizeof(trid));
573 ssize_t len = -1;
574 int64_t rto = 0;
575
576 do {
577 if (rto == 0) {
578 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
579
580 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
581 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
582 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
583
584 rto = (retx->init_timeo * 1000 + delay);
585 }
586 else
587 rto = (2 * rto + dhcpv6_rand_delay(rto));
588
589 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
590 rto = retx->max_timeo * 1000 +
591 dhcpv6_rand_delay(retx->max_timeo * 1000);
592
593 // Calculate end for this round and elapsed time
594 uint64_t round_end = round_start + rto;
595 elapsed = round_start - start;
596
597 // Don't wait too long if timeout differs from infinite
598 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
599 round_end = timeout * 1000 + start;
600
601 // Built and send package
602 switch (type) {
603 case DHCPV6_MSG_UNKNOWN:
604 break;
605 default:
606 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
607 retx->name, (unsigned long long)elapsed, rc);
608 // Fall through
609 case DHCPV6_MSG_SOLICIT:
610 case DHCPV6_MSG_INFO_REQ:
611 dhcpv6_send(type, trid, elapsed / 10);
612 rc++;
613 }
614
615 // Receive rounds
616 for (; len < 0 && (round_start < round_end);
617 round_start = odhcp6c_get_milli_time()) {
618 uint8_t buf[1536];
619 union {
620 struct cmsghdr hdr;
621 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
622 } cmsg_buf;
623 struct iovec iov = {buf, sizeof(buf)};
624 struct sockaddr_in6 addr;
625 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
626 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
627 .msg_controllen = sizeof(cmsg_buf)};
628 struct in6_pktinfo *pktinfo = NULL;
629
630
631 // Check for pending signal
632 if (odhcp6c_signal_process())
633 return -1;
634
635 // Set timeout for receiving
636 uint64_t t = round_end - round_start;
637 struct timeval tv = {t / 1000, (t % 1000) * 1000};
638 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
639 &tv, sizeof(tv));
640
641 // Receive cycle
642 len = recvmsg(sock, &msg, 0);
643 if (len < 0)
644 continue;
645
646 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
647 ch = CMSG_NXTHDR(&msg, ch)) {
648 if (ch->cmsg_level == SOL_IPV6 &&
649 ch->cmsg_type == IPV6_PKTINFO) {
650 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
651 break;
652 }
653 }
654
655 if (pktinfo == NULL) {
656 len = -1;
657 continue;
658 }
659
660 if (!dhcpv6_response_is_valid(buf, len, trid,
661 type, &pktinfo->ipi6_addr)) {
662 len = -1;
663 continue;
664 }
665
666 uint8_t *opt = &buf[4];
667 uint8_t *opt_end = opt + len - 4;
668
669 round_start = odhcp6c_get_milli_time();
670 elapsed = round_start - start;
671 syslog(LOG_NOTICE, "Got a valid reply after "
672 "%llums", (unsigned long long)elapsed);
673
674 if (retx->handler_reply)
675 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
676
677 if (len > 0 && round_end - round_start > 1000)
678 round_end = 1000 + round_start;
679 }
680
681 // Allow
682 if (retx->handler_finish)
683 len = retx->handler_finish();
684 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
685 (!retx->max_rc || rc < retx->max_rc));
686 return len;
687 }
688
689 // Message validation checks according to RFC3315 chapter 15
690 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
691 const uint8_t transaction[3], enum dhcpv6_msg type,
692 const struct in6_addr *daddr)
693 {
694 const struct dhcpv6_header *rep = buf;
695 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
696 transaction, sizeof(rep->tr_id)))
697 return false; // Invalid reply
698
699 if (type == DHCPV6_MSG_SOLICIT) {
700 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
701 rep->msg_type != DHCPV6_MSG_REPLY)
702 return false;
703 } else if (type == DHCPV6_MSG_UNKNOWN) {
704 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
705 return false;
706 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
707 return false;
708 }
709
710 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
711 rcmsg = DHCPV6_MSG_UNKNOWN;
712 uint16_t otype, olen = UINT16_MAX;
713 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
714 ia_present = false, options_valid = true;
715
716 size_t client_id_len, server_id_len;
717 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
718 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
719
720 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
721 if (otype == DHCPV6_OPT_CLIENTID) {
722 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
723 &odata[-4], client_id, client_id_len);
724 } else if (otype == DHCPV6_OPT_SERVERID) {
725 if (server_id_len)
726 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
727 &odata[-4], server_id, server_id_len);
728 else
729 serverid_ok = true;
730 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
731 sizeof(struct dhcpv6_auth_reconfigure)) {
732 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
733 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
734 continue;
735
736 md5_ctx_t md5;
737 uint8_t serverhash[16], secretbytes[64];
738 uint32_t hash[4];
739 memcpy(serverhash, r->key, sizeof(serverhash));
740 memset(r->key, 0, sizeof(r->key));
741
742 memset(secretbytes, 0, sizeof(secretbytes));
743 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
744
745 for (size_t i = 0; i < sizeof(secretbytes); ++i)
746 secretbytes[i] ^= 0x36;
747
748 md5_begin(&md5);
749 md5_hash(secretbytes, sizeof(secretbytes), &md5);
750 md5_hash(buf, len, &md5);
751 md5_end(hash, &md5);
752
753 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
754 secretbytes[i] ^= 0x36;
755 secretbytes[i] ^= 0x5c;
756 }
757
758 md5_begin(&md5);
759 md5_hash(secretbytes, sizeof(secretbytes), &md5);
760 md5_hash(hash, 16, &md5);
761 md5_end(hash, &md5);
762
763 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
764 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
765 rcmsg = odata[0];
766 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
767 ia_present = true;
768 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
769 options_valid = false;
770 }
771 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
772 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
773 // Options are not allowed on global level
774 options_valid = false;
775 }
776 }
777
778 if (!options_valid || ((odata + olen) > end))
779 return false;
780
781 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
782 return false;
783
784 if (rep->msg_type == DHCPV6_MSG_RECONF) {
785 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
786 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
787 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
788 return false;
789 }
790
791 return clientid_ok && serverid_ok;
792 }
793
794
795 int dhcpv6_poll_reconfigure(void)
796 {
797 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
798 if (ret != -1)
799 ret = dhcpv6_request(ret);
800
801 return ret;
802 }
803
804
805 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
806 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
807 {
808 uint16_t otype, olen;
809 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
810 dhcpv6_for_each_option(opt, end, otype, olen, odata)
811 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
812 odata[0] == DHCPV6_MSG_RENEW ||
813 odata[0] == DHCPV6_MSG_INFO_REQ))
814 msg = odata[0];
815
816 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
817 return msg;
818 }
819
820
821 // Collect all advertised servers
822 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
823 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
824 {
825 uint16_t olen, otype;
826 uint8_t *odata, pref = 0;
827 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
828 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
829 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
830 bool have_na = false;
831 int have_pd = 0;
832
833 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
834 if (orig == DHCPV6_MSG_SOLICIT &&
835 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
836 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
837 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
838 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
839 }
840
841 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
842 memcpy(cand.duid, odata, olen);
843 cand.duid_len = olen;
844 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
845 cand.preference >= 0) {
846 cand.preference = pref = odata[0];
847 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
848 cand.server_addr = *(struct in6_addr *)odata;
849 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
850 cand.wants_reconfigure = true;
851 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
852 uint32_t sol_max_rt = ntohl_unaligned(odata);
853 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
854 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
855 cand.sol_max_rt = sol_max_rt;
856 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
857 uint32_t inf_max_rt = ntohl_unaligned(odata);
858 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
859 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
860 cand.inf_max_rt = inf_max_rt;
861 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
862 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
863 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
864 uint8_t *oend = odata + olen, *d;
865 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
866 if (otype == DHCPV6_OPT_IA_PREFIX &&
867 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
868 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
869 have_pd = p->prefix;
870 }
871 }
872 } else if (otype == DHCPV6_OPT_IA_NA &&
873 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
874 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
875 uint8_t *oend = odata + olen, *d;
876 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
877 if (otype == DHCPV6_OPT_IA_ADDR &&
878 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
879 have_na = true;
880 }
881 }
882
883 if ((!have_na && na_mode == IA_MODE_FORCE) ||
884 (!have_pd && pd_mode == IA_MODE_FORCE)) {
885 /*
886 * RFC7083 states to process the SOL_MAX_RT and
887 * INF_MAX_RT options even if the DHCPv6 server
888 * did not propose any IA_NA and/or IA_PD
889 */
890 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
891 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
892 return -1;
893 }
894
895 if (na_mode != IA_MODE_NONE && !have_na) {
896 cand.has_noaddravail = true;
897 cand.preference -= 1000;
898 }
899
900 if (pd_mode != IA_MODE_NONE) {
901 if (have_pd)
902 cand.preference += 2000 + (128 - have_pd);
903 else
904 cand.preference -= 2000;
905 }
906
907 if (cand.duid_len > 0) {
908 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
909 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
910 dhcpv6_add_server_cand(&cand);
911 }
912
913 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
914 }
915
916
917 static int dhcpv6_commit_advert(void)
918 {
919 return dhcpv6_promote_server_cand();
920 }
921
922
923 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
924 const void *opt, const void *end, const struct sockaddr_in6 *from)
925 {
926 dhcpv6_handle_advert(orig, rc, opt, end, from);
927 if (dhcpv6_commit_advert() < 0)
928 return -1;
929
930 return dhcpv6_handle_reply(orig, rc, opt, end, from);
931 }
932
933
934 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
935 const void *opt, const void *end, const struct sockaddr_in6 *from)
936 {
937 uint8_t *odata;
938 uint16_t otype, olen;
939 uint32_t refresh = 86400;
940 int ret = 1;
941 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
942
943 odhcp6c_expire();
944
945 if (orig == DHCPV6_MSG_UNKNOWN) {
946 static time_t last_update = 0;
947 time_t now = odhcp6c_get_milli_time() / 1000;
948
949 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
950 last_update = now;
951
952 if (t1 != UINT32_MAX)
953 t1 -= elapsed;
954
955 if (t2 != UINT32_MAX)
956 t2 -= elapsed;
957
958 if (t3 != UINT32_MAX)
959 t3 -= elapsed;
960
961 if (t1 < 0)
962 t1 = 0;
963
964 if (t2 < 0)
965 t2 = 0;
966
967 if (t3 < 0)
968 t3 = 0;
969 }
970
971 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
972 // Delete NA and PD we have in the state from the Advert
973 odhcp6c_clear_state(STATE_IA_NA);
974 odhcp6c_clear_state(STATE_IA_PD);
975 }
976
977 if (opt) {
978 odhcp6c_clear_state(STATE_DNS);
979 odhcp6c_clear_state(STATE_SEARCH);
980 odhcp6c_clear_state(STATE_SNTP_IP);
981 odhcp6c_clear_state(STATE_NTP_IP);
982 odhcp6c_clear_state(STATE_NTP_FQDN);
983 odhcp6c_clear_state(STATE_SIP_IP);
984 odhcp6c_clear_state(STATE_SIP_FQDN);
985 odhcp6c_clear_state(STATE_AFTR_NAME);
986 odhcp6c_clear_state(STATE_CER);
987 odhcp6c_clear_state(STATE_S46_MAPT);
988 odhcp6c_clear_state(STATE_S46_MAPE);
989 odhcp6c_clear_state(STATE_S46_LW);
990 odhcp6c_clear_state(STATE_PASSTHRU);
991 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
992
993 // Parse and find all matching IAs
994 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
995 bool passthru = true;
996
997 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
998 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
999 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1000
1001 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1002 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1003 continue;
1004
1005 // Test ID
1006 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1007 continue;
1008
1009 uint16_t code = DHCPV6_Success;
1010 uint16_t stype, slen;
1011 uint8_t *sdata;
1012 // Get and handle status code
1013 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1014 stype, slen, sdata) {
1015 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1016 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1017 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1018
1019 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1020
1021 if (code == DHCPV6_Success)
1022 continue;
1023
1024 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1025 code, mdata, mlen, handled_status_codes, &ret);
1026
1027
1028 if (ret > 0)
1029 return ret;
1030 break;
1031 }
1032 }
1033
1034 if (code != DHCPV6_Success)
1035 continue;
1036
1037 dhcpv6_parse_ia(ia_hdr, odata + olen);
1038 passthru = false;
1039 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1040 server_addr = *(struct in6_addr *)odata;
1041 passthru = false;
1042 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1043 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1044 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1045 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1046
1047 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1048 passthru = false;
1049 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1050 if (olen % 16 == 0)
1051 odhcp6c_add_state(STATE_DNS, odata, olen);
1052 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1053 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1054 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1055 if (olen % 16 == 0)
1056 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1057 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1058 uint16_t stype, slen;
1059 uint8_t *sdata;
1060 // Test status and bail if error
1061 dhcpv6_for_each_option(odata, odata + olen,
1062 stype, slen, sdata) {
1063 if (slen == 16 && (stype == NTP_MC_ADDR ||
1064 stype == NTP_SRV_ADDR))
1065 odhcp6c_add_state(STATE_NTP_IP,
1066 sdata, slen);
1067 else if (slen > 0 && stype == NTP_SRV_FQDN)
1068 odhcp6c_add_state(STATE_NTP_FQDN,
1069 sdata, slen);
1070 }
1071 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1072 if (olen == 16)
1073 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1074 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1075 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1076 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1077 refresh = ntohl_unaligned(odata);
1078 passthru = false;
1079 } else if (otype == DHCPV6_OPT_AUTH) {
1080 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1081 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1082 if (r->protocol == 3 && r->algorithm == 1 &&
1083 r->reconf_type == 1)
1084 memcpy(reconf_key, r->key, sizeof(r->key));
1085 }
1086 passthru = false;
1087 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1088 size_t cur_len;
1089 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1090 if (cur_len == 0)
1091 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1092 passthru = false;
1093 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1094 uint32_t sol_max_rt = ntohl_unaligned(odata);
1095 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1096 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1097 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1098 passthru = false;
1099 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1100 uint32_t inf_max_rt = ntohl_unaligned(odata);
1101 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1102 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1103 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1104 passthru = false;
1105 #ifdef EXT_CER_ID
1106 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1107 sizeof(struct dhcpv6_cer_id)) {
1108 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1109 struct in6_addr any = IN6ADDR_ANY_INIT;
1110 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1111 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1112 passthru = false;
1113 #endif
1114 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1115 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1116 passthru = false;
1117 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1118 size_t mape_len;
1119 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1120 if (mape_len == 0)
1121 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1122 passthru = false;
1123 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1124 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1125 passthru = false;
1126 } else if (otype == DHCPV6_OPT_CLIENTID ||
1127 otype == DHCPV6_OPT_SERVERID ||
1128 otype == DHCPV6_OPT_IA_TA ||
1129 otype == DHCPV6_OPT_PREF ||
1130 otype == DHCPV6_OPT_UNICAST ||
1131 otype == DHCPV6_OPT_FQDN ||
1132 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1133 passthru = false;
1134 } else {
1135 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1136 }
1137
1138 if (passthru)
1139 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1140 }
1141 }
1142
1143 if (orig != DHCPV6_MSG_INFO_REQ) {
1144 // Update refresh timers if no fatal status code was received
1145 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1146 switch (orig) {
1147 case DHCPV6_MSG_RENEW:
1148 // Send further renews if T1 is not set
1149 if (!t1)
1150 ret = -1;
1151 break;
1152 case DHCPV6_MSG_REBIND:
1153 // Send further rebinds if T1 and T2 is not set
1154 if (!t1 && !t2)
1155 ret = -1;
1156 break;
1157
1158 case DHCPV6_MSG_REQUEST:
1159 // All server candidates can be cleared if not yet bound
1160 if (!odhcp6c_is_bound())
1161 dhcpv6_clear_all_server_cand();
1162
1163 default :
1164 break;
1165 }
1166
1167 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1168 odhcp6c_clear_state(STATE_SERVER_ADDR);
1169 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1170 }
1171 }
1172 }
1173 else if (ret > 0) {
1174 // All server candidates can be cleared if not yet bound
1175 if (!odhcp6c_is_bound())
1176 dhcpv6_clear_all_server_cand();
1177
1178 t1 = refresh;
1179 }
1180
1181 return ret;
1182 }
1183
1184
1185 static int dhcpv6_parse_ia(void *opt, void *end)
1186 {
1187 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1188 int parsed_ia = 0;
1189 uint32_t t1, t2;
1190 uint16_t otype, olen;
1191 uint8_t *odata;
1192
1193 t1 = ntohl(ia_hdr->t1);
1194 t2 = ntohl(ia_hdr->t2);
1195
1196 if (t1 > t2)
1197 return 0;
1198
1199 // Update address IA
1200 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1201 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1202 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1203
1204 entry.iaid = ia_hdr->iaid;
1205
1206 if (otype == DHCPV6_OPT_IA_PREFIX) {
1207 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1208 if (olen + 4U < sizeof(*prefix))
1209 continue;
1210
1211 entry.valid = ntohl(prefix->valid);
1212 entry.preferred = ntohl(prefix->preferred);
1213
1214 if (entry.preferred > entry.valid)
1215 continue;
1216
1217 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1218 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1219 if (entry.t1 > entry.t2)
1220 entry.t1 = entry.t2;
1221
1222 entry.length = prefix->prefix;
1223 entry.target = prefix->addr;
1224 uint16_t stype, slen;
1225 uint8_t *sdata;
1226
1227 // Parse PD-exclude
1228 bool ok = true;
1229 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1230 odata + olen, stype, slen, sdata) {
1231 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1232 continue;
1233
1234 uint8_t elen = sdata[0];
1235 if (elen > 64)
1236 elen = 64;
1237
1238 if (entry.length < 32 || elen <= entry.length) {
1239 ok = false;
1240 continue;
1241 }
1242
1243
1244 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1245 if (slen <= bytes) {
1246 ok = false;
1247 continue;
1248 }
1249
1250 uint32_t exclude = 0;
1251 do {
1252 exclude = exclude << 8 | sdata[bytes];
1253 } while (--bytes);
1254
1255 exclude >>= 8 - ((elen - entry.length) % 8);
1256 exclude <<= 64 - elen;
1257
1258 // Abusing router & priority fields for exclusion
1259 entry.router = entry.target;
1260 entry.router.s6_addr32[1] |= htonl(exclude);
1261 entry.priority = elen;
1262 }
1263
1264 if (ok) {
1265 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1266 parsed_ia++;
1267 }
1268
1269 entry.priority = 0;
1270 memset(&entry.router, 0, sizeof(entry.router));
1271 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1272 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1273 if (olen + 4U < sizeof(*addr))
1274 continue;
1275
1276 entry.preferred = ntohl(addr->preferred);
1277 entry.valid = ntohl(addr->valid);
1278
1279 if (entry.preferred > entry.valid)
1280 continue;
1281
1282 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1283 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1284 if (entry.t1 > entry.t2)
1285 entry.t1 = entry.t2;
1286
1287 entry.length = 128;
1288 entry.target = addr->addr;
1289
1290 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1291 parsed_ia++;
1292 }
1293 }
1294 return parsed_ia;
1295 }
1296
1297
1298 static int dhcpv6_calc_refresh_timers(void)
1299 {
1300 struct odhcp6c_entry *e;
1301 size_t ia_na_entries, ia_pd_entries, i;
1302 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1303
1304 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1305 ia_na_entries /= sizeof(*e);
1306 for (i = 0; i < ia_na_entries; i++) {
1307 if (e[i].t1 < l_t1)
1308 l_t1 = e[i].t1;
1309
1310 if (e[i].t2 < l_t2)
1311 l_t2 = e[i].t2;
1312
1313 if (e[i].valid > l_t3)
1314 l_t3 = e[i].valid;
1315 }
1316
1317 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1318 ia_pd_entries /= sizeof(*e);
1319 for (i = 0; i < ia_pd_entries; i++) {
1320 if (e[i].t1 < l_t1)
1321 l_t1 = e[i].t1;
1322
1323 if (e[i].t2 < l_t2)
1324 l_t2 = e[i].t2;
1325
1326 if (e[i].valid > l_t3)
1327 l_t3 = e[i].valid;
1328 }
1329
1330 if (ia_pd_entries || ia_na_entries) {
1331 t1 = l_t1;
1332 t2 = l_t2;
1333 t3 = l_t3;
1334 } else {
1335 t1 = 600;
1336 }
1337
1338 return (int)(ia_pd_entries + ia_na_entries);
1339 }
1340
1341
1342 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1343 const void *status_msg, int len)
1344 {
1345 const char *src = status_msg;
1346 char buf[len + 3];
1347 char *dst = buf;
1348
1349 if (len) {
1350 *dst++ = '(';
1351 while (len--) {
1352 *dst = isprint((unsigned char)*src) ? *src : '?';
1353 src++;
1354 dst++;
1355 }
1356 *dst++ = ')';
1357 }
1358 *dst = 0;
1359
1360 syslog(LOG_WARNING, "Server returned %s status %i %s",
1361 scope, code, buf);
1362 }
1363
1364
1365 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1366 const uint16_t code, const void *status_msg, const int len,
1367 int *ret)
1368 {
1369 dhcpv6_log_status_code(code, "message", status_msg, len);
1370
1371 switch (code) {
1372 case DHCPV6_UnspecFail:
1373 // Generic failure
1374 *ret = 0;
1375 break;
1376
1377 case DHCPV6_UseMulticast:
1378 switch(orig) {
1379 case DHCPV6_MSG_REQUEST:
1380 case DHCPV6_MSG_RENEW:
1381 case DHCPV6_MSG_RELEASE:
1382 case DHCPV6_MSG_DECLINE:
1383 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1384 server_addr = in6addr_any;
1385 *ret = 0;
1386 break;
1387 default:
1388 break;
1389 }
1390 break;
1391
1392 case DHCPV6_NoAddrsAvail:
1393 case DHCPV6_NoPrefixAvail:
1394 if (orig == DHCPV6_MSG_REQUEST)
1395 *ret = 0; // Failure
1396 break;
1397
1398 default:
1399 break;
1400 }
1401 }
1402
1403
1404 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1405 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1406 const void *status_msg, const int len,
1407 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1408 {
1409 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1410 "IA_NA" : "IA_PD", status_msg, len);
1411
1412 switch (code) {
1413 case DHCPV6_NoBinding:
1414 switch (orig) {
1415 case DHCPV6_MSG_RENEW:
1416 case DHCPV6_MSG_REBIND:
1417 if ((*ret > 0) && !handled_status_codes[code])
1418 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1419 break;
1420
1421 default:
1422 break;
1423 }
1424 break;
1425
1426 default:
1427 *ret = 0;
1428 break;
1429 }
1430 }
1431
1432 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1433 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1434 {
1435 size_t cand_len, i;
1436 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1437
1438 // Remove identical duid server candidate
1439 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1440 if (cand->duid_len == c[i].duid_len &&
1441 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1442 free(c[i].ia_na);
1443 free(c[i].ia_pd);
1444 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1445 break;
1446 }
1447 }
1448
1449 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1450 i < cand_len / sizeof(*c); ++i) {
1451 if (c[i].preference < cand->preference)
1452 break;
1453 }
1454
1455 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1456 free(cand->ia_na);
1457 free(cand->ia_pd);
1458 }
1459 }
1460
1461 static void dhcpv6_clear_all_server_cand(void)
1462 {
1463 size_t cand_len, i;
1464 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1465
1466 // Server candidates need deep delete for IA_NA/IA_PD
1467 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1468 free(c[i].ia_na);
1469 free(c[i].ia_pd);
1470 }
1471 odhcp6c_clear_state(STATE_SERVER_CAND);
1472 }
1473
1474 int dhcpv6_promote_server_cand(void)
1475 {
1476 size_t cand_len;
1477 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1478 uint16_t hdr[2];
1479 int ret = DHCPV6_STATELESS;
1480
1481 // Clear lingering candidate state info
1482 odhcp6c_clear_state(STATE_SERVER_ID);
1483 odhcp6c_clear_state(STATE_IA_NA);
1484 odhcp6c_clear_state(STATE_IA_PD);
1485
1486 if (!cand_len)
1487 return -1;
1488
1489 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1490 na_mode = IA_MODE_NONE;
1491
1492 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1493 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1494
1495 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1496 }
1497
1498 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1499 hdr[1] = htons(cand->duid_len);
1500 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1501 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1502 accept_reconfig = cand->wants_reconfigure;
1503 if (cand->ia_na_len) {
1504 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1505 free(cand->ia_na);
1506 if (na_mode != IA_MODE_NONE)
1507 ret = DHCPV6_STATEFUL;
1508 }
1509 if (cand->ia_pd_len) {
1510 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1511 free(cand->ia_pd);
1512 if (request_prefix)
1513 ret = DHCPV6_STATEFUL;
1514 }
1515
1516 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1517 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1518
1519 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1520
1521 return ret;
1522 }
Openwrt DHCPv6 Client