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dhcpv6: trigger restart of DHCPv6 state machine when not receiving statefull options
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017 Hans Dedecker <dedeckeh@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 */
15
16 #include <time.h>
17 #include <fcntl.h>
18 #include <errno.h>
19 #include <stdlib.h>
20 #include <signal.h>
21 #include <limits.h>
22 #include <resolv.h>
23 #include <string.h>
24 #include <unistd.h>
25 #include <syslog.h>
26 #include <stdbool.h>
27 #include <ctype.h>
28 #include <sys/time.h>
29 #include <sys/ioctl.h>
30 #include <sys/socket.h>
31 #include <arpa/inet.h>
32 #include <netinet/in.h>
33
34 #include <net/if.h>
35 #include <net/ethernet.h>
36
37 #include "odhcp6c.h"
38 #ifdef LIBUBOX
39 #include <libubox/md5.h>
40 #else
41 #include "md5.h"
42 #endif
43
44
45 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
46 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
47 #define DHCPV6_CLIENT_PORT 546
48 #define DHCPV6_SERVER_PORT 547
49 #define DHCPV6_DUID_LLADDR 3
50 #define DHCPV6_REQ_DELAY 1
51
52 #define DHCPV6_SOL_MAX_RT_MIN 60
53 #define DHCPV6_SOL_MAX_RT_MAX 86400
54 #define DHCPV6_INF_MAX_RT_MIN 60
55 #define DHCPV6_INF_MAX_RT_MAX 86400
56
57 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
58 const uint8_t transaction[3], enum dhcpv6_msg type,
59 const struct in6_addr *daddr);
60
61 static int dhcpv6_parse_ia(void *opt, void *end);
62
63 static int dhcpv6_calc_refresh_timers(void);
64 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
65 const uint16_t code, const void *status_msg, const int len,
66 int *ret);
67 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
68 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
69 const void *status_msg, const int len,
70 bool handled_status_codes[_DHCPV6_Status_Max],
71 int *ret);
72 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
73 static void dhcpv6_clear_all_server_cand(void);
74
75 static reply_handler dhcpv6_handle_reply;
76 static reply_handler dhcpv6_handle_advert;
77 static reply_handler dhcpv6_handle_rebind_reply;
78 static reply_handler dhcpv6_handle_reconfigure;
79 static int dhcpv6_commit_advert(void);
80
81
82
83 // RFC 3315 - 5.5 Timeout and Delay values
84 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
85 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
86 dhcpv6_handle_reconfigure, NULL},
87 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
88 dhcpv6_handle_advert, dhcpv6_commit_advert},
89 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
90 dhcpv6_handle_reply, NULL},
91 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
92 dhcpv6_handle_reply, NULL},
93 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
94 dhcpv6_handle_rebind_reply, NULL},
95 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
96 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
97 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
98 dhcpv6_handle_reply, NULL},
99 };
100
101
102 // Sockets
103 static int sock = -1;
104 static int ifindex = -1;
105 static int64_t t1 = 0, t2 = 0, t3 = 0;
106
107 // IA states
108 static int request_prefix = -1;
109 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
110 static bool accept_reconfig = false;
111 // Server unicast address
112 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
113
114 // Reconfigure key
115 static uint8_t reconf_key[16];
116
117 // client options
118 static unsigned int client_options = 0;
119
120
121 static uint32_t ntohl_unaligned(const uint8_t *data)
122 {
123 uint32_t buf;
124
125 memcpy(&buf, data, sizeof(buf));
126 return ntohl(buf);
127 }
128
129 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
130 {
131 client_options = options;
132 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
133
134 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
135 if (sock < 0)
136 return -1;
137
138 // Detect interface
139 struct ifreq ifr;
140 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
141 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
142 return -1;
143 ifindex = ifr.ifr_ifindex;
144
145 // Create client DUID
146 size_t client_id_len;
147 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
148 if (client_id_len == 0) {
149 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
150 DHCPV6_DUID_LLADDR, 0, 1};
151
152 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
153 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
154
155 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
156 struct ifreq ifs[100], *ifp, *ifend;
157 struct ifconf ifc;
158 ifc.ifc_req = ifs;
159 ifc.ifc_len = sizeof(ifs);
160
161 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
162 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
163 // If our interface doesn't have an address...
164 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
165 for (ifp = ifc.ifc_req; ifp < ifend &&
166 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
167 memcpy(ifr.ifr_name, ifp->ifr_name,
168 sizeof(ifr.ifr_name));
169 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
170 continue;
171
172 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
173 ETHER_ADDR_LEN);
174 }
175 }
176
177 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
178 }
179
180 // Create ORO
181 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
182 uint16_t oro[] = {
183 htons(DHCPV6_OPT_SIP_SERVER_D),
184 htons(DHCPV6_OPT_SIP_SERVER_A),
185 htons(DHCPV6_OPT_DNS_SERVERS),
186 htons(DHCPV6_OPT_DNS_DOMAIN),
187 htons(DHCPV6_OPT_UNICAST),
188 htons(DHCPV6_OPT_SNTP_SERVERS),
189 htons(DHCPV6_OPT_NTP_SERVER),
190 htons(DHCPV6_OPT_AFTR_NAME),
191 htons(DHCPV6_OPT_PD_EXCLUDE),
192 htons(DHCPV6_OPT_SOL_MAX_RT),
193 htons(DHCPV6_OPT_INF_MAX_RT),
194 #ifdef EXT_CER_ID
195 htons(DHCPV6_OPT_CER_ID),
196 #endif
197 htons(DHCPV6_OPT_S46_CONT_MAPE),
198 htons(DHCPV6_OPT_S46_CONT_MAPT),
199 htons(DHCPV6_OPT_S46_CONT_LW),
200 };
201 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
202 }
203
204 // Configure IPv6-options
205 int val = 1;
206 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
207 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
208 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
209 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
210
211 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
212 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
213 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
214 return -1;
215
216 return 0;
217 }
218
219 enum {
220 IOV_HDR=0,
221 IOV_ORO,
222 IOV_ORO_REFRESH,
223 IOV_CL_ID,
224 IOV_SRV_ID,
225 IOV_VENDOR_CLASS_HDR,
226 IOV_VENDOR_CLASS,
227 IOV_USER_CLASS_HDR,
228 IOV_USER_CLASS,
229 IOV_RECONF_ACCEPT,
230 IOV_FQDN,
231 IOV_HDR_IA_NA,
232 IOV_IA_NA,
233 IOV_IA_PD,
234 IOV_TOTAL
235 };
236
237 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
238 {
239 int mode = DHCPV6_UNKNOWN;
240
241 na_mode = na;
242 pd_mode = pd;
243
244 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
245 mode = DHCPV6_STATELESS;
246 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
247 mode = DHCPV6_STATEFUL;
248
249 return mode;
250 }
251
252 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
253 {
254 // Build FQDN
255 char fqdn_buf[256];
256 gethostname(fqdn_buf, sizeof(fqdn_buf));
257 struct {
258 uint16_t type;
259 uint16_t len;
260 uint8_t flags;
261 uint8_t data[256];
262 } fqdn;
263 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
264 sizeof(fqdn.data), NULL, NULL);
265 fqdn.type = htons(DHCPV6_OPT_FQDN);
266 fqdn.len = htons(fqdn_len - 4);
267 fqdn.flags = 0;
268
269
270 // Build Client ID
271 size_t cl_id_len;
272 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
273
274 // Get Server ID
275 size_t srv_id_len;
276 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
277
278 // Build IA_PDs
279 size_t ia_pd_entries = 0, ia_pd_len = 0;
280 uint8_t *ia_pd;
281
282 if (type == DHCPV6_MSG_SOLICIT) {
283 odhcp6c_clear_state(STATE_IA_PD);
284 size_t n_prefixes;
285 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
286 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
287
288 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
289
290 for (size_t i = 0; i < n_prefixes; i++) {
291 struct dhcpv6_ia_hdr hdr_ia_pd = {
292 htons(DHCPV6_OPT_IA_PD),
293 htons(sizeof(hdr_ia_pd) - 4 +
294 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
295 request_prefixes[i].iaid, 0, 0
296 };
297 struct dhcpv6_ia_prefix pref = {
298 .type = htons(DHCPV6_OPT_IA_PREFIX),
299 .len = htons(sizeof(pref) - 4),
300 .prefix = request_prefixes[i].length
301 };
302 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
303 ia_pd_len += sizeof(hdr_ia_pd);
304 if (request_prefixes[i].length) {
305 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
306 ia_pd_len += sizeof(pref);
307 }
308 }
309 } else {
310 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
311 ia_pd_entries /= sizeof(*e);
312
313 // we're too lazy to count our distinct IAIDs,
314 // so just allocate maximally needed space
315 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
316 sizeof(struct dhcpv6_ia_hdr)));
317
318 for (size_t i = 0; i < ia_pd_entries; ++i) {
319 uint32_t iaid = e[i].iaid;
320
321 // check if this is an unprocessed IAID and skip if not.
322 int new_iaid = 1;
323 for (int j = i-1; j >= 0; j--) {
324 if (e[j].iaid == iaid) {
325 new_iaid = 0;
326 break;
327 }
328 }
329
330 if (!new_iaid)
331 continue;
332
333 // construct header
334 struct dhcpv6_ia_hdr hdr_ia_pd = {
335 htons(DHCPV6_OPT_IA_PD),
336 htons(sizeof(hdr_ia_pd) - 4),
337 iaid, 0, 0
338 };
339
340 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
341 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
342 ia_pd_len += sizeof(hdr_ia_pd);
343
344 for (size_t j = i; j < ia_pd_entries; j++) {
345 if (e[j].iaid != iaid)
346 continue;
347
348 uint8_t ex_len = 0;
349 if (e[j].priority > 0)
350 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
351
352 struct dhcpv6_ia_prefix p = {
353 .type = htons(DHCPV6_OPT_IA_PREFIX),
354 .len = htons(sizeof(p) - 4U + ex_len),
355 .prefix = e[j].length,
356 .addr = e[j].target
357 };
358
359 if (type == DHCPV6_MSG_REQUEST) {
360 p.preferred = htonl(e[j].preferred);
361 p.valid = htonl(e[j].valid);
362 }
363
364 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
365 ia_pd_len += sizeof(p);
366
367 if (ex_len) {
368 ia_pd[ia_pd_len++] = 0;
369 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
370 ia_pd[ia_pd_len++] = 0;
371 ia_pd[ia_pd_len++] = ex_len - 4;
372 ia_pd[ia_pd_len++] = e[j].priority;
373
374 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
375 excl >>= (64 - e[j].priority);
376 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
377
378 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
379 ia_pd[ia_pd_len + i] = excl & 0xff;
380 ia_pd_len += ex_len - 5;
381 }
382
383 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
384 }
385 }
386 }
387
388 if (ia_pd_entries > 0)
389 request_prefix = 1;
390
391 // Build IA_NAs
392 size_t ia_na_entries, ia_na_len = 0;
393 void *ia_na = NULL;
394 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
395 ia_na_entries /= sizeof(*e);
396
397 struct dhcpv6_ia_hdr hdr_ia_na = {
398 htons(DHCPV6_OPT_IA_NA),
399 htons(sizeof(hdr_ia_na) - 4),
400 htonl(1), 0, 0
401 };
402
403 struct dhcpv6_ia_addr pa[ia_na_entries];
404 for (size_t i = 0; i < ia_na_entries; ++i) {
405 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
406 pa[i].len = htons(sizeof(pa[i]) - 4U);
407 pa[i].addr = e[i].target;
408
409 if (type == DHCPV6_MSG_REQUEST) {
410 pa[i].preferred = htonl(e[i].preferred);
411 pa[i].valid = htonl(e[i].valid);
412 } else {
413 pa[i].preferred = 0;
414 pa[i].valid = 0;
415 }
416 }
417
418 ia_na = pa;
419 ia_na_len = sizeof(pa);
420 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
421
422 // Reconfigure Accept
423 struct {
424 uint16_t type;
425 uint16_t length;
426 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
427
428 // Request Information Refresh
429 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
430
431 // Build vendor-class option
432 size_t vendor_class_len, user_class_len;
433 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
434 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
435
436 struct {
437 uint16_t type;
438 uint16_t length;
439 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
440
441 struct {
442 uint16_t type;
443 uint16_t length;
444 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
445
446 // Prepare Header
447 size_t oro_len;
448 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
449 struct {
450 uint8_t type;
451 uint8_t trid[3];
452 uint16_t elapsed_type;
453 uint16_t elapsed_len;
454 uint16_t elapsed_value;
455 uint16_t oro_type;
456 uint16_t oro_len;
457 } hdr = {
458 type, {trid[0], trid[1], trid[2]},
459 htons(DHCPV6_OPT_ELAPSED), htons(2),
460 htons((ecs > 0xffff) ? 0xffff : ecs),
461 htons(DHCPV6_OPT_ORO), htons(oro_len),
462 };
463
464 struct iovec iov[IOV_TOTAL] = {
465 [IOV_HDR] = {&hdr, sizeof(hdr)},
466 [IOV_ORO] = {oro, oro_len},
467 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
468 [IOV_CL_ID] = {cl_id, cl_id_len},
469 [IOV_SRV_ID] = {srv_id, srv_id_len},
470 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
471 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
472 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
473 [IOV_USER_CLASS] = {user_class, user_class_len},
474 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
475 [IOV_FQDN] = {&fqdn, fqdn_len},
476 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
477 [IOV_IA_NA] = {ia_na, ia_na_len},
478 [IOV_IA_PD] = {ia_pd, ia_pd_len},
479 };
480
481 size_t cnt = IOV_TOTAL;
482 if (type == DHCPV6_MSG_INFO_REQ) {
483 cnt = 9;
484 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
485 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
486 } else if (!request_prefix) {
487 cnt = 13;
488 }
489
490 // Disable IAs if not used
491 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
492 iov[IOV_HDR_IA_NA].iov_len = 0;
493
494 if (na_mode == IA_MODE_NONE)
495 iov[IOV_HDR_IA_NA].iov_len = 0;
496
497 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
498 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
499 iov[IOV_RECONF_ACCEPT].iov_len = 0;
500
501 if (!(client_options & DHCPV6_CLIENT_FQDN))
502 iov[IOV_FQDN].iov_len = 0;
503
504 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
505 0, ALL_DHCPV6_RELAYS, ifindex};
506 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
507 .msg_iov = iov, .msg_iovlen = cnt};
508
509 switch (type) {
510 case DHCPV6_MSG_REQUEST:
511 case DHCPV6_MSG_RENEW:
512 case DHCPV6_MSG_RELEASE:
513 case DHCPV6_MSG_DECLINE:
514 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
515 odhcp6c_addr_in_scope(&server_addr)) {
516 srv.sin6_addr = server_addr;
517 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
518 srv.sin6_scope_id = 0;
519 }
520 break;
521 default:
522 break;
523 }
524
525 if (sendmsg(sock, &msg, 0) < 0) {
526 char in6_str[INET6_ADDRSTRLEN];
527
528 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
529 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
530 in6_str, sizeof(in6_str)), strerror(errno));
531 }
532 }
533
534
535 static int64_t dhcpv6_rand_delay(int64_t time)
536 {
537 int random;
538 odhcp6c_random(&random, sizeof(random));
539 return (time * ((int64_t)random % 1000LL)) / 10000LL;
540 }
541
542
543 int dhcpv6_request(enum dhcpv6_msg type)
544 {
545 uint8_t rc = 0;
546 uint64_t timeout = UINT32_MAX;
547 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
548
549 if (retx->delay) {
550 struct timespec ts = {0, 0};
551 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
552 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
553 }
554
555 if (type == DHCPV6_MSG_UNKNOWN)
556 timeout = t1;
557 else if (type == DHCPV6_MSG_RENEW)
558 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
559 else if (type == DHCPV6_MSG_REBIND)
560 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
561
562 if (timeout == 0)
563 return -1;
564
565 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
566 retx->name, (unsigned long long)timeout, retx->max_rc);
567
568 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
569
570 // Generate transaction ID
571 uint8_t trid[3] = {0, 0, 0};
572 if (type != DHCPV6_MSG_UNKNOWN)
573 odhcp6c_random(trid, sizeof(trid));
574 ssize_t len = -1;
575 int64_t rto = 0;
576
577 do {
578 if (rto == 0) {
579 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
580
581 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
582 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
583 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
584
585 rto = (retx->init_timeo * 1000 + delay);
586 }
587 else
588 rto = (2 * rto + dhcpv6_rand_delay(rto));
589
590 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
591 rto = retx->max_timeo * 1000 +
592 dhcpv6_rand_delay(retx->max_timeo * 1000);
593
594 // Calculate end for this round and elapsed time
595 uint64_t round_end = round_start + rto;
596 elapsed = round_start - start;
597
598 // Don't wait too long if timeout differs from infinite
599 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
600 round_end = timeout * 1000 + start;
601
602 // Built and send package
603 switch (type) {
604 case DHCPV6_MSG_UNKNOWN:
605 break;
606 default:
607 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
608 retx->name, (unsigned long long)elapsed, rc);
609 // Fall through
610 case DHCPV6_MSG_SOLICIT:
611 case DHCPV6_MSG_INFO_REQ:
612 dhcpv6_send(type, trid, elapsed / 10);
613 rc++;
614 }
615
616 // Receive rounds
617 for (; len < 0 && (round_start < round_end);
618 round_start = odhcp6c_get_milli_time()) {
619 uint8_t buf[1536];
620 union {
621 struct cmsghdr hdr;
622 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
623 } cmsg_buf;
624 struct iovec iov = {buf, sizeof(buf)};
625 struct sockaddr_in6 addr;
626 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
627 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
628 .msg_controllen = sizeof(cmsg_buf)};
629 struct in6_pktinfo *pktinfo = NULL;
630
631
632 // Check for pending signal
633 if (odhcp6c_signal_process())
634 return -1;
635
636 // Set timeout for receiving
637 uint64_t t = round_end - round_start;
638 struct timeval tv = {t / 1000, (t % 1000) * 1000};
639 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
640 &tv, sizeof(tv));
641
642 // Receive cycle
643 len = recvmsg(sock, &msg, 0);
644 if (len < 0)
645 continue;
646
647 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
648 ch = CMSG_NXTHDR(&msg, ch)) {
649 if (ch->cmsg_level == SOL_IPV6 &&
650 ch->cmsg_type == IPV6_PKTINFO) {
651 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
652 break;
653 }
654 }
655
656 if (pktinfo == NULL) {
657 len = -1;
658 continue;
659 }
660
661 if (!dhcpv6_response_is_valid(buf, len, trid,
662 type, &pktinfo->ipi6_addr)) {
663 len = -1;
664 continue;
665 }
666
667 uint8_t *opt = &buf[4];
668 uint8_t *opt_end = opt + len - 4;
669
670 round_start = odhcp6c_get_milli_time();
671 elapsed = round_start - start;
672 syslog(LOG_NOTICE, "Got a valid reply after "
673 "%llums", (unsigned long long)elapsed);
674
675 if (retx->handler_reply)
676 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
677
678 if (len > 0 && round_end - round_start > 1000)
679 round_end = 1000 + round_start;
680 }
681
682 // Allow
683 if (retx->handler_finish)
684 len = retx->handler_finish();
685 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
686 (!retx->max_rc || rc < retx->max_rc));
687 return len;
688 }
689
690 // Message validation checks according to RFC3315 chapter 15
691 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
692 const uint8_t transaction[3], enum dhcpv6_msg type,
693 const struct in6_addr *daddr)
694 {
695 const struct dhcpv6_header *rep = buf;
696 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
697 transaction, sizeof(rep->tr_id)))
698 return false; // Invalid reply
699
700 if (type == DHCPV6_MSG_SOLICIT) {
701 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
702 rep->msg_type != DHCPV6_MSG_REPLY)
703 return false;
704 } else if (type == DHCPV6_MSG_UNKNOWN) {
705 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
706 return false;
707 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
708 return false;
709 }
710
711 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
712 rcmsg = DHCPV6_MSG_UNKNOWN;
713 uint16_t otype, olen = UINT16_MAX;
714 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
715 ia_present = false, options_valid = true;
716
717 size_t client_id_len, server_id_len;
718 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
719 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
720
721 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
722 if (otype == DHCPV6_OPT_CLIENTID) {
723 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
724 &odata[-4], client_id, client_id_len);
725 } else if (otype == DHCPV6_OPT_SERVERID) {
726 if (server_id_len)
727 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
728 &odata[-4], server_id, server_id_len);
729 else
730 serverid_ok = true;
731 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
732 sizeof(struct dhcpv6_auth_reconfigure)) {
733 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
734 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
735 continue;
736
737 md5_ctx_t md5;
738 uint8_t serverhash[16], secretbytes[64];
739 uint32_t hash[4];
740 memcpy(serverhash, r->key, sizeof(serverhash));
741 memset(r->key, 0, sizeof(r->key));
742
743 memset(secretbytes, 0, sizeof(secretbytes));
744 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
745
746 for (size_t i = 0; i < sizeof(secretbytes); ++i)
747 secretbytes[i] ^= 0x36;
748
749 md5_begin(&md5);
750 md5_hash(secretbytes, sizeof(secretbytes), &md5);
751 md5_hash(buf, len, &md5);
752 md5_end(hash, &md5);
753
754 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
755 secretbytes[i] ^= 0x36;
756 secretbytes[i] ^= 0x5c;
757 }
758
759 md5_begin(&md5);
760 md5_hash(secretbytes, sizeof(secretbytes), &md5);
761 md5_hash(hash, 16, &md5);
762 md5_end(hash, &md5);
763
764 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
765 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
766 rcmsg = odata[0];
767 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
768 ia_present = true;
769 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
770 options_valid = false;
771 }
772 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
773 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
774 // Options are not allowed on global level
775 options_valid = false;
776 }
777 }
778
779 if (!options_valid || ((odata + olen) > end))
780 return false;
781
782 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
783 return false;
784
785 if (rep->msg_type == DHCPV6_MSG_RECONF) {
786 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
787 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
788 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
789 return false;
790 }
791
792 return clientid_ok && serverid_ok;
793 }
794
795
796 int dhcpv6_poll_reconfigure(void)
797 {
798 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
799 if (ret != -1)
800 ret = dhcpv6_request(ret);
801
802 return ret;
803 }
804
805
806 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
807 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
808 {
809 uint16_t otype, olen;
810 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
811 dhcpv6_for_each_option(opt, end, otype, olen, odata)
812 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
813 odata[0] == DHCPV6_MSG_RENEW ||
814 odata[0] == DHCPV6_MSG_INFO_REQ))
815 msg = odata[0];
816
817 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
818 return msg;
819 }
820
821
822 // Collect all advertised servers
823 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
824 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
825 {
826 uint16_t olen, otype;
827 uint8_t *odata, pref = 0;
828 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
829 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
830 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
831 bool have_na = false;
832 int have_pd = 0;
833
834 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
835 if (orig == DHCPV6_MSG_SOLICIT &&
836 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
837 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
838 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
839 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
840 }
841
842 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
843 memcpy(cand.duid, odata, olen);
844 cand.duid_len = olen;
845 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
846 cand.preference >= 0) {
847 cand.preference = pref = odata[0];
848 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
849 cand.server_addr = *(struct in6_addr *)odata;
850 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
851 cand.wants_reconfigure = true;
852 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
853 uint32_t sol_max_rt = ntohl_unaligned(odata);
854 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
855 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
856 cand.sol_max_rt = sol_max_rt;
857 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
858 uint32_t inf_max_rt = ntohl_unaligned(odata);
859 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
860 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
861 cand.inf_max_rt = inf_max_rt;
862 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
863 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
864 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
865 uint8_t *oend = odata + olen, *d;
866 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
867 if (otype == DHCPV6_OPT_IA_PREFIX &&
868 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
869 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
870 have_pd = p->prefix;
871 }
872 }
873 } else if (otype == DHCPV6_OPT_IA_NA &&
874 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
875 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
876 uint8_t *oend = odata + olen, *d;
877 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
878 if (otype == DHCPV6_OPT_IA_ADDR &&
879 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
880 have_na = true;
881 }
882 }
883
884 if ((!have_na && na_mode == IA_MODE_FORCE) ||
885 (!have_pd && pd_mode == IA_MODE_FORCE)) {
886 /*
887 * RFC7083 states to process the SOL_MAX_RT and
888 * INF_MAX_RT options even if the DHCPv6 server
889 * did not propose any IA_NA and/or IA_PD
890 */
891 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
892 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
893 return -1;
894 }
895
896 if (na_mode != IA_MODE_NONE && !have_na) {
897 cand.has_noaddravail = true;
898 cand.preference -= 1000;
899 }
900
901 if (pd_mode != IA_MODE_NONE) {
902 if (have_pd)
903 cand.preference += 2000 + (128 - have_pd);
904 else
905 cand.preference -= 2000;
906 }
907
908 if (cand.duid_len > 0) {
909 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
910 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
911 dhcpv6_add_server_cand(&cand);
912 }
913
914 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
915 }
916
917
918 static int dhcpv6_commit_advert(void)
919 {
920 return dhcpv6_promote_server_cand();
921 }
922
923
924 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
925 const void *opt, const void *end, const struct sockaddr_in6 *from)
926 {
927 dhcpv6_handle_advert(orig, rc, opt, end, from);
928 if (dhcpv6_commit_advert() < 0)
929 return -1;
930
931 return dhcpv6_handle_reply(orig, rc, opt, end, from);
932 }
933
934
935 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
936 const void *opt, const void *end, const struct sockaddr_in6 *from)
937 {
938 uint8_t *odata;
939 uint16_t otype, olen;
940 uint32_t refresh = 86400;
941 int ret = 1;
942 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
943
944 odhcp6c_expire();
945
946 if (orig == DHCPV6_MSG_UNKNOWN) {
947 static time_t last_update = 0;
948 time_t now = odhcp6c_get_milli_time() / 1000;
949
950 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
951 last_update = now;
952
953 if (t1 != UINT32_MAX)
954 t1 -= elapsed;
955
956 if (t2 != UINT32_MAX)
957 t2 -= elapsed;
958
959 if (t3 != UINT32_MAX)
960 t3 -= elapsed;
961
962 if (t1 < 0)
963 t1 = 0;
964
965 if (t2 < 0)
966 t2 = 0;
967
968 if (t3 < 0)
969 t3 = 0;
970 }
971
972 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
973 // Delete NA and PD we have in the state from the Advert
974 odhcp6c_clear_state(STATE_IA_NA);
975 odhcp6c_clear_state(STATE_IA_PD);
976 }
977
978 if (opt) {
979 odhcp6c_clear_state(STATE_DNS);
980 odhcp6c_clear_state(STATE_SEARCH);
981 odhcp6c_clear_state(STATE_SNTP_IP);
982 odhcp6c_clear_state(STATE_NTP_IP);
983 odhcp6c_clear_state(STATE_NTP_FQDN);
984 odhcp6c_clear_state(STATE_SIP_IP);
985 odhcp6c_clear_state(STATE_SIP_FQDN);
986 odhcp6c_clear_state(STATE_AFTR_NAME);
987 odhcp6c_clear_state(STATE_CER);
988 odhcp6c_clear_state(STATE_S46_MAPT);
989 odhcp6c_clear_state(STATE_S46_MAPE);
990 odhcp6c_clear_state(STATE_S46_LW);
991 odhcp6c_clear_state(STATE_PASSTHRU);
992 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
993
994 // Parse and find all matching IAs
995 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
996 bool passthru = true;
997
998 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
999 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1000 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1001
1002 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1003 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1004 continue;
1005
1006 // Test ID
1007 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1008 continue;
1009
1010 uint16_t code = DHCPV6_Success;
1011 uint16_t stype, slen;
1012 uint8_t *sdata;
1013 // Get and handle status code
1014 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1015 stype, slen, sdata) {
1016 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1017 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1018 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1019
1020 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1021
1022 if (code == DHCPV6_Success)
1023 continue;
1024
1025 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1026 code, mdata, mlen, handled_status_codes, &ret);
1027
1028
1029 if (ret > 0)
1030 return ret;
1031 break;
1032 }
1033 }
1034
1035 if (code != DHCPV6_Success)
1036 continue;
1037
1038 dhcpv6_parse_ia(ia_hdr, odata + olen);
1039 passthru = false;
1040 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1041 server_addr = *(struct in6_addr *)odata;
1042 passthru = false;
1043 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1044 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1045 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1046 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1047
1048 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1049 passthru = false;
1050 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1051 if (olen % 16 == 0)
1052 odhcp6c_add_state(STATE_DNS, odata, olen);
1053 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1054 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1055 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1056 if (olen % 16 == 0)
1057 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1058 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1059 uint16_t stype, slen;
1060 uint8_t *sdata;
1061 // Test status and bail if error
1062 dhcpv6_for_each_option(odata, odata + olen,
1063 stype, slen, sdata) {
1064 if (slen == 16 && (stype == NTP_MC_ADDR ||
1065 stype == NTP_SRV_ADDR))
1066 odhcp6c_add_state(STATE_NTP_IP,
1067 sdata, slen);
1068 else if (slen > 0 && stype == NTP_SRV_FQDN)
1069 odhcp6c_add_state(STATE_NTP_FQDN,
1070 sdata, slen);
1071 }
1072 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1073 if (olen == 16)
1074 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1075 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1076 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1077 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1078 refresh = ntohl_unaligned(odata);
1079 passthru = false;
1080 } else if (otype == DHCPV6_OPT_AUTH) {
1081 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1082 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1083 if (r->protocol == 3 && r->algorithm == 1 &&
1084 r->reconf_type == 1)
1085 memcpy(reconf_key, r->key, sizeof(r->key));
1086 }
1087 passthru = false;
1088 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1089 size_t cur_len;
1090 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1091 if (cur_len == 0)
1092 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1093 passthru = false;
1094 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1095 uint32_t sol_max_rt = ntohl_unaligned(odata);
1096 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1097 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1098 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1099 passthru = false;
1100 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1101 uint32_t inf_max_rt = ntohl_unaligned(odata);
1102 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1103 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1104 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1105 passthru = false;
1106 #ifdef EXT_CER_ID
1107 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1108 sizeof(struct dhcpv6_cer_id)) {
1109 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1110 struct in6_addr any = IN6ADDR_ANY_INIT;
1111 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1112 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1113 passthru = false;
1114 #endif
1115 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1116 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1117 passthru = false;
1118 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1119 size_t mape_len;
1120 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1121 if (mape_len == 0)
1122 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1123 passthru = false;
1124 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1125 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1126 passthru = false;
1127 } else if (otype == DHCPV6_OPT_CLIENTID ||
1128 otype == DHCPV6_OPT_SERVERID ||
1129 otype == DHCPV6_OPT_IA_TA ||
1130 otype == DHCPV6_OPT_PREF ||
1131 otype == DHCPV6_OPT_UNICAST ||
1132 otype == DHCPV6_OPT_FQDN ||
1133 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1134 passthru = false;
1135 } else {
1136 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1137 }
1138
1139 if (passthru)
1140 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1141 }
1142 }
1143
1144 if (orig != DHCPV6_MSG_INFO_REQ) {
1145 // Update refresh timers if no fatal status code was received
1146 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1147 switch (orig) {
1148 case DHCPV6_MSG_RENEW:
1149 // Send further renews if T1 is not set
1150 if (!t1)
1151 ret = -1;
1152 break;
1153 case DHCPV6_MSG_REBIND:
1154 // Send further rebinds if T1 and T2 is not set
1155 if (!t1 && !t2)
1156 ret = -1;
1157 break;
1158
1159 case DHCPV6_MSG_REQUEST:
1160 // All server candidates can be cleared if not yet bound
1161 if (!odhcp6c_is_bound())
1162 dhcpv6_clear_all_server_cand();
1163
1164 default :
1165 break;
1166 }
1167
1168 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1169 odhcp6c_clear_state(STATE_SERVER_ADDR);
1170 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1171 }
1172 }
1173 }
1174 else if (ret > 0) {
1175 // All server candidates can be cleared if not yet bound
1176 if (!odhcp6c_is_bound())
1177 dhcpv6_clear_all_server_cand();
1178
1179 t1 = refresh;
1180 }
1181
1182 return ret;
1183 }
1184
1185
1186 static int dhcpv6_parse_ia(void *opt, void *end)
1187 {
1188 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1189 int parsed_ia = 0;
1190 uint32_t t1, t2;
1191 uint16_t otype, olen;
1192 uint8_t *odata;
1193
1194 t1 = ntohl(ia_hdr->t1);
1195 t2 = ntohl(ia_hdr->t2);
1196
1197 if (t1 > t2)
1198 return 0;
1199
1200 // Update address IA
1201 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1202 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1203 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1204
1205 entry.iaid = ia_hdr->iaid;
1206
1207 if (otype == DHCPV6_OPT_IA_PREFIX) {
1208 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1209 if (olen + 4U < sizeof(*prefix))
1210 continue;
1211
1212 entry.valid = ntohl(prefix->valid);
1213 entry.preferred = ntohl(prefix->preferred);
1214
1215 if (entry.preferred > entry.valid)
1216 continue;
1217
1218 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1219 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1220 if (entry.t1 > entry.t2)
1221 entry.t1 = entry.t2;
1222
1223 entry.length = prefix->prefix;
1224 entry.target = prefix->addr;
1225 uint16_t stype, slen;
1226 uint8_t *sdata;
1227
1228 // Parse PD-exclude
1229 bool ok = true;
1230 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1231 odata + olen, stype, slen, sdata) {
1232 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1233 continue;
1234
1235 uint8_t elen = sdata[0];
1236 if (elen > 64)
1237 elen = 64;
1238
1239 if (entry.length < 32 || elen <= entry.length) {
1240 ok = false;
1241 continue;
1242 }
1243
1244
1245 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1246 if (slen <= bytes) {
1247 ok = false;
1248 continue;
1249 }
1250
1251 uint32_t exclude = 0;
1252 do {
1253 exclude = exclude << 8 | sdata[bytes];
1254 } while (--bytes);
1255
1256 exclude >>= 8 - ((elen - entry.length) % 8);
1257 exclude <<= 64 - elen;
1258
1259 // Abusing router & priority fields for exclusion
1260 entry.router = entry.target;
1261 entry.router.s6_addr32[1] |= htonl(exclude);
1262 entry.priority = elen;
1263 }
1264
1265 if (ok) {
1266 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1267 parsed_ia++;
1268 }
1269
1270 entry.priority = 0;
1271 memset(&entry.router, 0, sizeof(entry.router));
1272 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1273 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1274 if (olen + 4U < sizeof(*addr))
1275 continue;
1276
1277 entry.preferred = ntohl(addr->preferred);
1278 entry.valid = ntohl(addr->valid);
1279
1280 if (entry.preferred > entry.valid)
1281 continue;
1282
1283 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1284 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1285 if (entry.t1 > entry.t2)
1286 entry.t1 = entry.t2;
1287
1288 entry.length = 128;
1289 entry.target = addr->addr;
1290
1291 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1292 parsed_ia++;
1293 }
1294 }
1295 return parsed_ia;
1296 }
1297
1298
1299 static int dhcpv6_calc_refresh_timers(void)
1300 {
1301 struct odhcp6c_entry *e;
1302 size_t ia_na_entries, ia_pd_entries, i;
1303 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1304
1305 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1306 ia_na_entries /= sizeof(*e);
1307 for (i = 0; i < ia_na_entries; i++) {
1308 if (e[i].t1 < l_t1)
1309 l_t1 = e[i].t1;
1310
1311 if (e[i].t2 < l_t2)
1312 l_t2 = e[i].t2;
1313
1314 if (e[i].valid > l_t3)
1315 l_t3 = e[i].valid;
1316 }
1317
1318 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1319 ia_pd_entries /= sizeof(*e);
1320 for (i = 0; i < ia_pd_entries; i++) {
1321 if (e[i].t1 < l_t1)
1322 l_t1 = e[i].t1;
1323
1324 if (e[i].t2 < l_t2)
1325 l_t2 = e[i].t2;
1326
1327 if (e[i].valid > l_t3)
1328 l_t3 = e[i].valid;
1329 }
1330
1331 if (ia_pd_entries || ia_na_entries) {
1332 t1 = l_t1;
1333 t2 = l_t2;
1334 t3 = l_t3;
1335 }
1336
1337 return (int)(ia_pd_entries + ia_na_entries);
1338 }
1339
1340
1341 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1342 const void *status_msg, int len)
1343 {
1344 const char *src = status_msg;
1345 char buf[len + 3];
1346 char *dst = buf;
1347
1348 if (len) {
1349 *dst++ = '(';
1350 while (len--) {
1351 *dst = isprint((unsigned char)*src) ? *src : '?';
1352 src++;
1353 dst++;
1354 }
1355 *dst++ = ')';
1356 }
1357 *dst = 0;
1358
1359 syslog(LOG_WARNING, "Server returned %s status %i %s",
1360 scope, code, buf);
1361 }
1362
1363
1364 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1365 const uint16_t code, const void *status_msg, const int len,
1366 int *ret)
1367 {
1368 dhcpv6_log_status_code(code, "message", status_msg, len);
1369
1370 switch (code) {
1371 case DHCPV6_UnspecFail:
1372 // Generic failure
1373 *ret = 0;
1374 break;
1375
1376 case DHCPV6_UseMulticast:
1377 switch(orig) {
1378 case DHCPV6_MSG_REQUEST:
1379 case DHCPV6_MSG_RENEW:
1380 case DHCPV6_MSG_RELEASE:
1381 case DHCPV6_MSG_DECLINE:
1382 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1383 server_addr = in6addr_any;
1384 *ret = 0;
1385 break;
1386 default:
1387 break;
1388 }
1389 break;
1390
1391 case DHCPV6_NoAddrsAvail:
1392 case DHCPV6_NoPrefixAvail:
1393 if (orig == DHCPV6_MSG_REQUEST)
1394 *ret = 0; // Failure
1395 break;
1396
1397 default:
1398 break;
1399 }
1400 }
1401
1402
1403 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1404 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1405 const void *status_msg, const int len,
1406 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1407 {
1408 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1409 "IA_NA" : "IA_PD", status_msg, len);
1410
1411 switch (code) {
1412 case DHCPV6_NoBinding:
1413 switch (orig) {
1414 case DHCPV6_MSG_RENEW:
1415 case DHCPV6_MSG_REBIND:
1416 if ((*ret > 0) && !handled_status_codes[code])
1417 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1418 break;
1419
1420 default:
1421 break;
1422 }
1423 break;
1424
1425 default:
1426 *ret = 0;
1427 break;
1428 }
1429 }
1430
1431 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1432 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1433 {
1434 size_t cand_len, i;
1435 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1436
1437 // Remove identical duid server candidate
1438 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1439 if (cand->duid_len == c[i].duid_len &&
1440 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1441 free(c[i].ia_na);
1442 free(c[i].ia_pd);
1443 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1444 break;
1445 }
1446 }
1447
1448 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1449 i < cand_len / sizeof(*c); ++i) {
1450 if (c[i].preference < cand->preference)
1451 break;
1452 }
1453
1454 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1455 free(cand->ia_na);
1456 free(cand->ia_pd);
1457 }
1458 }
1459
1460 static void dhcpv6_clear_all_server_cand(void)
1461 {
1462 size_t cand_len, i;
1463 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1464
1465 // Server candidates need deep delete for IA_NA/IA_PD
1466 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1467 free(c[i].ia_na);
1468 free(c[i].ia_pd);
1469 }
1470 odhcp6c_clear_state(STATE_SERVER_CAND);
1471 }
1472
1473 int dhcpv6_promote_server_cand(void)
1474 {
1475 size_t cand_len;
1476 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1477 uint16_t hdr[2];
1478 int ret = DHCPV6_STATELESS;
1479
1480 // Clear lingering candidate state info
1481 odhcp6c_clear_state(STATE_SERVER_ID);
1482 odhcp6c_clear_state(STATE_IA_NA);
1483 odhcp6c_clear_state(STATE_IA_PD);
1484
1485 if (!cand_len)
1486 return -1;
1487
1488 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1489 na_mode = IA_MODE_NONE;
1490
1491 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1492 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1493
1494 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1495 }
1496
1497 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1498 hdr[1] = htons(cand->duid_len);
1499 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1500 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1501 accept_reconfig = cand->wants_reconfigure;
1502 if (cand->ia_na_len) {
1503 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1504 free(cand->ia_na);
1505 if (na_mode != IA_MODE_NONE)
1506 ret = DHCPV6_STATEFUL;
1507 }
1508 if (cand->ia_pd_len) {
1509 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1510 free(cand->ia_pd);
1511 if (request_prefix)
1512 ret = DHCPV6_STATEFUL;
1513 }
1514
1515 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1516 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1517
1518 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1519
1520 return ret;
1521 }
Openwrt DHCPv6 Client