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odhcp6c: rework userclass and vendorclass command handling
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 */
15
16 #include <time.h>
17 #include <fcntl.h>
18 #include <errno.h>
19 #include <inttypes.h>
20 #include <stdlib.h>
21 #include <signal.h>
22 #include <limits.h>
23 #include <resolv.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <syslog.h>
27 #include <stdbool.h>
28 #include <ctype.h>
29 #include <sys/time.h>
30 #include <sys/ioctl.h>
31 #include <sys/socket.h>
32 #include <arpa/inet.h>
33 #include <netinet/in.h>
34
35 #include <net/if.h>
36 #include <net/ethernet.h>
37
38 #include "odhcp6c.h"
39 #ifdef USE_LIBUBOX
40 #include <libubox/md5.h>
41 #else
42 #include "md5.h"
43 #endif
44
45
46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
47 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
48 #define DHCPV6_CLIENT_PORT 546
49 #define DHCPV6_SERVER_PORT 547
50 #define DHCPV6_DUID_LLADDR 3
51 #define DHCPV6_REQ_DELAY 1
52
53 #define DHCPV6_SOL_MAX_RT_MIN 60
54 #define DHCPV6_SOL_MAX_RT_MAX 86400
55 #define DHCPV6_INF_MAX_RT_MIN 60
56 #define DHCPV6_INF_MAX_RT_MAX 86400
57
58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
59 const uint8_t transaction[3], enum dhcpv6_msg type,
60 const struct in6_addr *daddr);
61
62 static int dhcpv6_parse_ia(void *opt, void *end);
63
64 static int dhcpv6_calc_refresh_timers(void);
65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
66 const uint16_t code, const void *status_msg, const int len,
67 int *ret);
68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
69 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
70 const void *status_msg, const int len,
71 bool handled_status_codes[_DHCPV6_Status_Max],
72 int *ret);
73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
74 static void dhcpv6_clear_all_server_cand(void);
75
76 static reply_handler dhcpv6_handle_reply;
77 static reply_handler dhcpv6_handle_advert;
78 static reply_handler dhcpv6_handle_rebind_reply;
79 static reply_handler dhcpv6_handle_reconfigure;
80 static int dhcpv6_commit_advert(void);
81
82 // RFC 3315 - 5.5 Timeout and Delay values
83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
84 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
85 dhcpv6_handle_reconfigure, NULL},
86 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
87 dhcpv6_handle_advert, dhcpv6_commit_advert},
88 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
89 dhcpv6_handle_reply, NULL},
90 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
91 dhcpv6_handle_reply, NULL},
92 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
93 dhcpv6_handle_rebind_reply, NULL},
94 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
95 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
96 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
97 dhcpv6_handle_reply, NULL},
98 };
99
100 // Sockets
101 static int sock = -1;
102 static int ifindex = -1;
103 static int64_t t1 = 0, t2 = 0, t3 = 0;
104
105 // IA states
106 static int request_prefix = -1;
107 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
108 static bool accept_reconfig = false;
109 // Server unicast address
110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
111
112 // Reconfigure key
113 static uint8_t reconf_key[16];
114
115 // client options
116 static unsigned int client_options = 0;
117
118 static uint32_t ntohl_unaligned(const uint8_t *data)
119 {
120 uint32_t buf;
121
122 memcpy(&buf, data, sizeof(buf));
123 return ntohl(buf);
124 }
125
126 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
127 {
128 client_options = options;
129 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
130
131 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
132 if (sock < 0)
133 return -1;
134
135 // Detect interface
136 struct ifreq ifr;
137 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
138 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
139 return -1;
140
141 ifindex = ifr.ifr_ifindex;
142
143 // Create client DUID
144 size_t client_id_len;
145 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
146 if (client_id_len == 0) {
147 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
148 DHCPV6_DUID_LLADDR, 0, 1};
149
150 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
151 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
152
153 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
154 struct ifreq ifs[100], *ifp, *ifend;
155 struct ifconf ifc;
156 ifc.ifc_req = ifs;
157 ifc.ifc_len = sizeof(ifs);
158
159 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
160 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
161 // If our interface doesn't have an address...
162 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
163 for (ifp = ifc.ifc_req; ifp < ifend &&
164 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
165 memcpy(ifr.ifr_name, ifp->ifr_name,
166 sizeof(ifr.ifr_name));
167 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
168 continue;
169
170 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
171 ETHER_ADDR_LEN);
172 }
173 }
174
175 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
176 }
177
178 // Create ORO
179 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
180 uint16_t oro[] = {
181 htons(DHCPV6_OPT_SIP_SERVER_D),
182 htons(DHCPV6_OPT_SIP_SERVER_A),
183 htons(DHCPV6_OPT_DNS_SERVERS),
184 htons(DHCPV6_OPT_DNS_DOMAIN),
185 htons(DHCPV6_OPT_UNICAST),
186 htons(DHCPV6_OPT_SNTP_SERVERS),
187 htons(DHCPV6_OPT_NTP_SERVER),
188 htons(DHCPV6_OPT_AFTR_NAME),
189 htons(DHCPV6_OPT_PD_EXCLUDE),
190 htons(DHCPV6_OPT_SOL_MAX_RT),
191 htons(DHCPV6_OPT_INF_MAX_RT),
192 #ifdef EXT_CER_ID
193 htons(DHCPV6_OPT_CER_ID),
194 #endif
195 htons(DHCPV6_OPT_S46_CONT_MAPE),
196 htons(DHCPV6_OPT_S46_CONT_MAPT),
197 htons(DHCPV6_OPT_S46_CONT_LW),
198 };
199 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
200 }
201
202 // Configure IPv6-options
203 int val = 1;
204 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
205 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
206 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
207 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
208
209 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
210 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
211
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_OPTS,
225 IOV_RECONF_ACCEPT,
226 IOV_FQDN,
227 IOV_HDR_IA_NA,
228 IOV_IA_NA,
229 IOV_IA_PD,
230 IOV_TOTAL
231 };
232
233 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
234 {
235 int mode = DHCPV6_UNKNOWN;
236
237 na_mode = na;
238 pd_mode = pd;
239
240 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
241 mode = DHCPV6_STATELESS;
242 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
243 mode = DHCPV6_STATEFUL;
244
245 return mode;
246 }
247
248 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
249 {
250 // Build FQDN
251 char fqdn_buf[256];
252 gethostname(fqdn_buf, sizeof(fqdn_buf));
253 struct {
254 uint16_t type;
255 uint16_t len;
256 uint8_t flags;
257 uint8_t data[256];
258 } fqdn;
259 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
260 sizeof(fqdn.data), NULL, NULL);
261 fqdn.type = htons(DHCPV6_OPT_FQDN);
262 fqdn.len = htons(fqdn_len - 4);
263 fqdn.flags = 0;
264
265 // Build Client ID
266 size_t cl_id_len;
267 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
268
269 // Get Server ID
270 size_t srv_id_len;
271 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
272
273 // Build IA_PDs
274 size_t ia_pd_entries = 0, ia_pd_len = 0;
275 uint8_t *ia_pd;
276
277 if (type == DHCPV6_MSG_SOLICIT) {
278 odhcp6c_clear_state(STATE_IA_PD);
279 size_t n_prefixes;
280 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
281 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
282
283 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
284
285 for (size_t i = 0; i < n_prefixes; i++) {
286 struct dhcpv6_ia_hdr hdr_ia_pd = {
287 htons(DHCPV6_OPT_IA_PD),
288 htons(sizeof(hdr_ia_pd) - 4 +
289 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
290 request_prefixes[i].iaid, 0, 0
291 };
292 struct dhcpv6_ia_prefix pref = {
293 .type = htons(DHCPV6_OPT_IA_PREFIX),
294 .len = htons(sizeof(pref) - 4),
295 .prefix = request_prefixes[i].length
296 };
297 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
298 ia_pd_len += sizeof(hdr_ia_pd);
299 if (request_prefixes[i].length) {
300 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
301 ia_pd_len += sizeof(pref);
302 }
303 }
304 } else {
305 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
306 ia_pd_entries /= sizeof(*e);
307
308 // we're too lazy to count our distinct IAIDs,
309 // so just allocate maximally needed space
310 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
311 sizeof(struct dhcpv6_ia_hdr)));
312
313 for (size_t i = 0; i < ia_pd_entries; ++i) {
314 uint32_t iaid = e[i].iaid;
315
316 // check if this is an unprocessed IAID and skip if not.
317 int new_iaid = 1;
318 for (int j = i-1; j >= 0; j--) {
319 if (e[j].iaid == iaid) {
320 new_iaid = 0;
321 break;
322 }
323 }
324
325 if (!new_iaid)
326 continue;
327
328 // construct header
329 struct dhcpv6_ia_hdr hdr_ia_pd = {
330 htons(DHCPV6_OPT_IA_PD),
331 htons(sizeof(hdr_ia_pd) - 4),
332 iaid, 0, 0
333 };
334
335 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
336 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
337 ia_pd_len += sizeof(hdr_ia_pd);
338
339 for (size_t j = i; j < ia_pd_entries; j++) {
340 if (e[j].iaid != iaid)
341 continue;
342
343 uint8_t ex_len = 0;
344 if (e[j].priority > 0)
345 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
346
347 struct dhcpv6_ia_prefix p = {
348 .type = htons(DHCPV6_OPT_IA_PREFIX),
349 .len = htons(sizeof(p) - 4U + ex_len),
350 .prefix = e[j].length,
351 .addr = e[j].target
352 };
353
354 if (type == DHCPV6_MSG_REQUEST) {
355 p.preferred = htonl(e[j].preferred);
356 p.valid = htonl(e[j].valid);
357 }
358
359 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
360 ia_pd_len += sizeof(p);
361
362 if (ex_len) {
363 ia_pd[ia_pd_len++] = 0;
364 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
365 ia_pd[ia_pd_len++] = 0;
366 ia_pd[ia_pd_len++] = ex_len - 4;
367 ia_pd[ia_pd_len++] = e[j].priority;
368
369 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
370 excl >>= (64 - e[j].priority);
371 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
372
373 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
374 ia_pd[ia_pd_len + i] = excl & 0xff;
375 ia_pd_len += ex_len - 5;
376 }
377
378 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
379 }
380 }
381 }
382
383 if (ia_pd_entries > 0)
384 request_prefix = 1;
385
386 // Build IA_NAs
387 size_t ia_na_entries, ia_na_len = 0;
388 void *ia_na = NULL;
389 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
390 ia_na_entries /= sizeof(*e);
391
392 struct dhcpv6_ia_hdr hdr_ia_na = {
393 htons(DHCPV6_OPT_IA_NA),
394 htons(sizeof(hdr_ia_na) - 4),
395 htonl(1), 0, 0
396 };
397
398 struct dhcpv6_ia_addr pa[ia_na_entries];
399 for (size_t i = 0; i < ia_na_entries; ++i) {
400 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
401 pa[i].len = htons(sizeof(pa[i]) - 4U);
402 pa[i].addr = e[i].target;
403
404 if (type == DHCPV6_MSG_REQUEST) {
405 pa[i].preferred = htonl(e[i].preferred);
406 pa[i].valid = htonl(e[i].valid);
407 } else {
408 pa[i].preferred = 0;
409 pa[i].valid = 0;
410 }
411 }
412
413 ia_na = pa;
414 ia_na_len = sizeof(pa);
415 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
416
417 // Reconfigure Accept
418 struct {
419 uint16_t type;
420 uint16_t length;
421 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
422
423 // Request Information Refresh
424 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
425
426 // Option list
427 size_t opts_len;
428 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
429
430 // Prepare Header
431 size_t oro_len;
432 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
433 struct {
434 uint8_t type;
435 uint8_t trid[3];
436 uint16_t elapsed_type;
437 uint16_t elapsed_len;
438 uint16_t elapsed_value;
439 uint16_t oro_type;
440 uint16_t oro_len;
441 } hdr = {
442 type, {trid[0], trid[1], trid[2]},
443 htons(DHCPV6_OPT_ELAPSED), htons(2),
444 htons((ecs > 0xffff) ? 0xffff : ecs),
445 htons(DHCPV6_OPT_ORO), htons(oro_len),
446 };
447
448 struct iovec iov[IOV_TOTAL] = {
449 [IOV_HDR] = {&hdr, sizeof(hdr)},
450 [IOV_ORO] = {oro, oro_len},
451 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
452 [IOV_CL_ID] = {cl_id, cl_id_len},
453 [IOV_SRV_ID] = {srv_id, srv_id_len},
454 [IOV_OPTS] = { opts, opts_len },
455 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
456 [IOV_FQDN] = {&fqdn, fqdn_len},
457 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
458 [IOV_IA_NA] = {ia_na, ia_na_len},
459 [IOV_IA_PD] = {ia_pd, ia_pd_len},
460 };
461
462 size_t cnt = IOV_TOTAL;
463 if (type == DHCPV6_MSG_INFO_REQ) {
464 cnt = 9;
465 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
466 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
467 } else if (!request_prefix)
468 cnt = 13;
469
470 // Disable IAs if not used
471 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
472 iov[IOV_HDR_IA_NA].iov_len = 0;
473
474 if (na_mode == IA_MODE_NONE)
475 iov[IOV_HDR_IA_NA].iov_len = 0;
476
477 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
478 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
479 iov[IOV_RECONF_ACCEPT].iov_len = 0;
480
481 if (!(client_options & DHCPV6_CLIENT_FQDN))
482 iov[IOV_FQDN].iov_len = 0;
483
484 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
485 0, ALL_DHCPV6_RELAYS, ifindex};
486 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
487 .msg_iov = iov, .msg_iovlen = cnt};
488
489 switch (type) {
490 case DHCPV6_MSG_REQUEST:
491 case DHCPV6_MSG_RENEW:
492 case DHCPV6_MSG_RELEASE:
493 case DHCPV6_MSG_DECLINE:
494 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
495 odhcp6c_addr_in_scope(&server_addr)) {
496 srv.sin6_addr = server_addr;
497 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
498 srv.sin6_scope_id = 0;
499 }
500 break;
501 default:
502 break;
503 }
504
505 if (sendmsg(sock, &msg, 0) < 0) {
506 char in6_str[INET6_ADDRSTRLEN];
507
508 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
509 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
510 in6_str, sizeof(in6_str)), strerror(errno));
511 }
512 }
513
514 static int64_t dhcpv6_rand_delay(int64_t time)
515 {
516 int random;
517 odhcp6c_random(&random, sizeof(random));
518
519 return (time * ((int64_t)random % 1000LL)) / 10000LL;
520 }
521
522 int dhcpv6_request(enum dhcpv6_msg type)
523 {
524 uint8_t rc = 0;
525 uint64_t timeout = UINT32_MAX;
526 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
527
528 if (retx->delay) {
529 struct timespec ts = {0, 0};
530 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
531
532 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
533 }
534
535 if (type == DHCPV6_MSG_UNKNOWN)
536 timeout = t1;
537 else if (type == DHCPV6_MSG_RENEW)
538 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
539 else if (type == DHCPV6_MSG_REBIND)
540 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
541
542 if (timeout == 0)
543 return -1;
544
545 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
546 retx->name, timeout, retx->max_rc);
547
548 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
549
550 // Generate transaction ID
551 uint8_t trid[3] = {0, 0, 0};
552 if (type != DHCPV6_MSG_UNKNOWN)
553 odhcp6c_random(trid, sizeof(trid));
554
555 ssize_t len = -1;
556 int64_t rto = 0;
557
558 do {
559 if (rto == 0) {
560 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
561
562 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
563 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
564 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
565
566 rto = (retx->init_timeo * 1000 + delay);
567 } else
568 rto = (2 * rto + dhcpv6_rand_delay(rto));
569
570 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
571 rto = retx->max_timeo * 1000 +
572 dhcpv6_rand_delay(retx->max_timeo * 1000);
573
574 // Calculate end for this round and elapsed time
575 uint64_t round_end = round_start + rto;
576 elapsed = round_start - start;
577
578 // Don't wait too long if timeout differs from infinite
579 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
580 round_end = timeout * 1000 + start;
581
582 // Built and send package
583 switch (type) {
584 case DHCPV6_MSG_UNKNOWN:
585 break;
586 default:
587 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
588 retx->name, elapsed, rc);
589 // Fall through
590 case DHCPV6_MSG_SOLICIT:
591 case DHCPV6_MSG_INFO_REQ:
592 dhcpv6_send(type, trid, elapsed / 10);
593 rc++;
594 }
595
596 // Receive rounds
597 for (; len < 0 && (round_start < round_end);
598 round_start = odhcp6c_get_milli_time()) {
599 uint8_t buf[1536];
600 union {
601 struct cmsghdr hdr;
602 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
603 } cmsg_buf;
604 struct iovec iov = {buf, sizeof(buf)};
605 struct sockaddr_in6 addr;
606 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
607 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
608 .msg_controllen = sizeof(cmsg_buf)};
609 struct in6_pktinfo *pktinfo = NULL;
610
611 // Check for pending signal
612 if (odhcp6c_signal_process())
613 return -1;
614
615 // Set timeout for receiving
616 uint64_t t = round_end - round_start;
617 struct timeval tv = {t / 1000, (t % 1000) * 1000};
618 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
619 &tv, sizeof(tv));
620
621 // Receive cycle
622 len = recvmsg(sock, &msg, 0);
623 if (len < 0)
624 continue;
625
626 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
627 ch = CMSG_NXTHDR(&msg, ch)) {
628 if (ch->cmsg_level == SOL_IPV6 &&
629 ch->cmsg_type == IPV6_PKTINFO) {
630 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
631 break;
632 }
633 }
634
635 if (pktinfo == NULL) {
636 len = -1;
637 continue;
638 }
639
640 if (!dhcpv6_response_is_valid(buf, len, trid,
641 type, &pktinfo->ipi6_addr)) {
642 len = -1;
643 continue;
644 }
645
646 uint8_t *opt = &buf[4];
647 uint8_t *opt_end = opt + len - 4;
648
649 round_start = odhcp6c_get_milli_time();
650 elapsed = round_start - start;
651 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
652 elapsed);
653
654 if (retx->handler_reply)
655 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
656
657 if (len > 0 && round_end - round_start > 1000)
658 round_end = 1000 + round_start;
659 }
660
661 // Allow
662 if (retx->handler_finish)
663 len = retx->handler_finish();
664 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
665 (!retx->max_rc || rc < retx->max_rc));
666 return len;
667 }
668
669 // Message validation checks according to RFC3315 chapter 15
670 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
671 const uint8_t transaction[3], enum dhcpv6_msg type,
672 const struct in6_addr *daddr)
673 {
674 const struct dhcpv6_header *rep = buf;
675 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
676 transaction, sizeof(rep->tr_id)))
677 return false; // Invalid reply
678
679 if (type == DHCPV6_MSG_SOLICIT) {
680 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
681 rep->msg_type != DHCPV6_MSG_REPLY)
682 return false;
683
684 } else if (type == DHCPV6_MSG_UNKNOWN) {
685 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
686 return false;
687
688 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
689 return false;
690
691 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
692 rcmsg = DHCPV6_MSG_UNKNOWN;
693 uint16_t otype, olen = UINT16_MAX;
694 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
695 ia_present = false, options_valid = true;
696
697 size_t client_id_len, server_id_len;
698 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
699 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
700
701 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
702 if (otype == DHCPV6_OPT_CLIENTID) {
703 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
704 &odata[-4], client_id, client_id_len);
705 } else if (otype == DHCPV6_OPT_SERVERID) {
706 if (server_id_len)
707 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
708 &odata[-4], server_id, server_id_len);
709 else
710 serverid_ok = true;
711 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
712 sizeof(struct dhcpv6_auth_reconfigure)) {
713 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
714 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
715 continue;
716
717 md5_ctx_t md5;
718 uint8_t serverhash[16], secretbytes[64];
719 uint32_t hash[4];
720 memcpy(serverhash, r->key, sizeof(serverhash));
721 memset(r->key, 0, sizeof(r->key));
722
723 memset(secretbytes, 0, sizeof(secretbytes));
724 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
725
726 for (size_t i = 0; i < sizeof(secretbytes); ++i)
727 secretbytes[i] ^= 0x36;
728
729 md5_begin(&md5);
730 md5_hash(secretbytes, sizeof(secretbytes), &md5);
731 md5_hash(buf, len, &md5);
732 md5_end(hash, &md5);
733
734 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
735 secretbytes[i] ^= 0x36;
736 secretbytes[i] ^= 0x5c;
737 }
738
739 md5_begin(&md5);
740 md5_hash(secretbytes, sizeof(secretbytes), &md5);
741 md5_hash(hash, 16, &md5);
742 md5_end(hash, &md5);
743
744 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
745 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
746 rcmsg = odata[0];
747 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
748 ia_present = true;
749 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
750 options_valid = false;
751 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
752 (otype == DHCPV6_OPT_PD_EXCLUDE))
753 // Options are not allowed on global level
754 options_valid = false;
755 }
756
757 if (!options_valid || ((odata + olen) > end))
758 return false;
759
760 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
761 return false;
762
763 if (rep->msg_type == DHCPV6_MSG_RECONF) {
764 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
765 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
766 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
767 return false;
768 }
769
770 return clientid_ok && serverid_ok;
771 }
772
773 int dhcpv6_poll_reconfigure(void)
774 {
775 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
776
777 if (ret != -1)
778 ret = dhcpv6_request(ret);
779
780 return ret;
781 }
782
783 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
784 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
785 {
786 uint16_t otype, olen;
787 uint8_t *odata;
788 int msg = -1;
789
790 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
791 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
792 switch (odata[0]) {
793 case DHCPV6_MSG_REBIND:
794 if (t2 != UINT32_MAX)
795 t2 = 0;
796 // Fall through
797 case DHCPV6_MSG_RENEW:
798 if (t1 != UINT32_MAX)
799 t1 = 0;
800 // Fall through
801 case DHCPV6_MSG_INFO_REQ:
802 msg = odata[0];
803 break;
804
805 default:
806 break;
807 }
808 }
809 }
810
811 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
812
813 return msg;
814 }
815
816 // Collect all advertised servers
817 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
818 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
819 {
820 uint16_t olen, otype;
821 uint8_t *odata, pref = 0;
822 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
823 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
824 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
825 bool have_na = false;
826 int have_pd = 0;
827
828 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
829 if (orig == DHCPV6_MSG_SOLICIT &&
830 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
831 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
832 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
833 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
834 }
835
836 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
837 memcpy(cand.duid, odata, olen);
838 cand.duid_len = olen;
839 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
840 cand.preference >= 0) {
841 cand.preference = pref = odata[0];
842 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
843 cand.server_addr = *(struct in6_addr *)odata;
844 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
845 cand.wants_reconfigure = true;
846 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
847 uint32_t sol_max_rt = ntohl_unaligned(odata);
848 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
849 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
850 cand.sol_max_rt = sol_max_rt;
851
852 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
853 uint32_t inf_max_rt = ntohl_unaligned(odata);
854 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
855 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
856 cand.inf_max_rt = inf_max_rt;
857
858 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
859 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
860 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
861 uint8_t *oend = odata + olen, *d;
862 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
863 if (otype == DHCPV6_OPT_IA_PREFIX &&
864 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
865 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
866 have_pd = p->prefix;
867 }
868 }
869 } else if (otype == DHCPV6_OPT_IA_NA &&
870 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
871 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
872 uint8_t *oend = odata + olen, *d;
873
874 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
875 if (otype == DHCPV6_OPT_IA_ADDR &&
876 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
877 have_na = true;
878 }
879 }
880 }
881
882 if ((!have_na && na_mode == IA_MODE_FORCE) ||
883 (!have_pd && pd_mode == IA_MODE_FORCE)) {
884 /*
885 * RFC7083 states to process the SOL_MAX_RT and
886 * INF_MAX_RT options even if the DHCPv6 server
887 * did not propose any IA_NA and/or IA_PD
888 */
889 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
890 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
891 return -1;
892 }
893
894 if (na_mode != IA_MODE_NONE && !have_na) {
895 cand.has_noaddravail = true;
896 cand.preference -= 1000;
897 }
898
899 if (pd_mode != IA_MODE_NONE) {
900 if (have_pd)
901 cand.preference += 2000 + (128 - have_pd);
902 else
903 cand.preference -= 2000;
904 }
905
906 if (cand.duid_len > 0) {
907 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
908 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
909 dhcpv6_add_server_cand(&cand);
910 }
911
912 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
913 }
914
915 static int dhcpv6_commit_advert(void)
916 {
917 return dhcpv6_promote_server_cand();
918 }
919
920 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
921 const void *opt, const void *end, const struct sockaddr_in6 *from)
922 {
923 dhcpv6_handle_advert(orig, rc, opt, end, from);
924 if (dhcpv6_commit_advert() < 0)
925 return -1;
926
927 return dhcpv6_handle_reply(orig, rc, opt, end, from);
928 }
929
930 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
931 const void *opt, const void *end, const struct sockaddr_in6 *from)
932 {
933 uint8_t *odata;
934 uint16_t otype, olen;
935 uint32_t refresh = 86400;
936 int ret = 1;
937 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
938
939 odhcp6c_expire();
940
941 if (orig == DHCPV6_MSG_UNKNOWN) {
942 static time_t last_update = 0;
943 time_t now = odhcp6c_get_milli_time() / 1000;
944
945 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
946 last_update = now;
947
948 if (t1 != UINT32_MAX)
949 t1 -= elapsed;
950
951 if (t2 != UINT32_MAX)
952 t2 -= elapsed;
953
954 if (t3 != UINT32_MAX)
955 t3 -= elapsed;
956
957 if (t1 < 0)
958 t1 = 0;
959
960 if (t2 < 0)
961 t2 = 0;
962
963 if (t3 < 0)
964 t3 = 0;
965 }
966
967 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
968 // Delete NA and PD we have in the state from the Advert
969 odhcp6c_clear_state(STATE_IA_NA);
970 odhcp6c_clear_state(STATE_IA_PD);
971 }
972
973 if (opt) {
974 odhcp6c_clear_state(STATE_DNS);
975 odhcp6c_clear_state(STATE_SEARCH);
976 odhcp6c_clear_state(STATE_SNTP_IP);
977 odhcp6c_clear_state(STATE_NTP_IP);
978 odhcp6c_clear_state(STATE_NTP_FQDN);
979 odhcp6c_clear_state(STATE_SIP_IP);
980 odhcp6c_clear_state(STATE_SIP_FQDN);
981 odhcp6c_clear_state(STATE_AFTR_NAME);
982 odhcp6c_clear_state(STATE_CER);
983 odhcp6c_clear_state(STATE_S46_MAPT);
984 odhcp6c_clear_state(STATE_S46_MAPE);
985 odhcp6c_clear_state(STATE_S46_LW);
986 odhcp6c_clear_state(STATE_PASSTHRU);
987 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
988
989 // Parse and find all matching IAs
990 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
991 bool passthru = true;
992
993 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
994 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
995 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
996
997 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
998 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
999 continue;
1000
1001 // Test ID
1002 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1003 continue;
1004
1005 uint16_t code = DHCPV6_Success;
1006 uint16_t stype, slen;
1007 uint8_t *sdata;
1008 // Get and handle status code
1009 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1010 stype, slen, sdata) {
1011 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1012 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1013 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1014
1015 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1016
1017 if (code == DHCPV6_Success)
1018 continue;
1019
1020 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1021 code, mdata, mlen, handled_status_codes, &ret);
1022
1023 if (ret > 0)
1024 return ret;
1025
1026 break;
1027 }
1028 }
1029
1030 if (code != DHCPV6_Success)
1031 continue;
1032
1033 dhcpv6_parse_ia(ia_hdr, odata + olen);
1034 passthru = false;
1035 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1036 server_addr = *(struct in6_addr *)odata;
1037 passthru = false;
1038 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1039 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1040 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1041 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1042
1043 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1044 passthru = false;
1045 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1046 if (olen % 16 == 0)
1047 odhcp6c_add_state(STATE_DNS, odata, olen);
1048 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1049 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1050 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1051 if (olen % 16 == 0)
1052 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1053 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1054 uint16_t stype, slen;
1055 uint8_t *sdata;
1056 // Test status and bail if error
1057 dhcpv6_for_each_option(odata, odata + olen,
1058 stype, slen, sdata) {
1059 if (slen == 16 && (stype == NTP_MC_ADDR ||
1060 stype == NTP_SRV_ADDR))
1061 odhcp6c_add_state(STATE_NTP_IP,
1062 sdata, slen);
1063 else if (slen > 0 && stype == NTP_SRV_FQDN)
1064 odhcp6c_add_state(STATE_NTP_FQDN,
1065 sdata, slen);
1066 }
1067 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1068 if (olen == 16)
1069 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1070 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1071 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1072 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1073 refresh = ntohl_unaligned(odata);
1074 passthru = false;
1075 } else if (otype == DHCPV6_OPT_AUTH) {
1076 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1077 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1078 if (r->protocol == 3 && r->algorithm == 1 &&
1079 r->reconf_type == 1)
1080 memcpy(reconf_key, r->key, sizeof(r->key));
1081 }
1082 passthru = false;
1083 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1084 size_t cur_len;
1085 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1086 if (cur_len == 0)
1087 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1088 passthru = false;
1089 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1090 uint32_t sol_max_rt = ntohl_unaligned(odata);
1091 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1092 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1093 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1094 passthru = false;
1095 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1096 uint32_t inf_max_rt = ntohl_unaligned(odata);
1097 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1098 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1099 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1100 passthru = false;
1101 #ifdef EXT_CER_ID
1102 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1103 sizeof(struct dhcpv6_cer_id)) {
1104 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1105 struct in6_addr any = IN6ADDR_ANY_INIT;
1106 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1107 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1108 passthru = false;
1109 #endif
1110 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1111 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1112 passthru = false;
1113 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1114 size_t mape_len;
1115 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1116 if (mape_len == 0)
1117 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1118 passthru = false;
1119 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1120 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1121 passthru = false;
1122 } else if (otype == DHCPV6_OPT_CLIENTID ||
1123 otype == DHCPV6_OPT_SERVERID ||
1124 otype == DHCPV6_OPT_IA_TA ||
1125 otype == DHCPV6_OPT_PREF ||
1126 otype == DHCPV6_OPT_UNICAST ||
1127 otype == DHCPV6_OPT_FQDN ||
1128 otype == DHCPV6_OPT_RECONF_ACCEPT)
1129 passthru = false;
1130 else
1131 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1132
1133 if (passthru)
1134 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1135 }
1136 }
1137
1138 switch (orig) {
1139 case DHCPV6_MSG_REQUEST:
1140 case DHCPV6_MSG_REBIND:
1141 case DHCPV6_MSG_RENEW:
1142 // Update refresh timers if no fatal status code was received
1143 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1144 if (orig == DHCPV6_MSG_REQUEST) {
1145 // All server candidates can be cleared if not yet bound
1146 if (!odhcp6c_is_bound())
1147 dhcpv6_clear_all_server_cand();
1148
1149 odhcp6c_clear_state(STATE_SERVER_ADDR);
1150 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1151 } else if (orig == DHCPV6_MSG_RENEW) {
1152 // Send further renews if T1 is not set
1153 if (!t1)
1154 ret = -1;
1155
1156 } else if (orig == DHCPV6_MSG_REBIND) {
1157 // Send further rebinds if T1 and T2 is not set
1158 if (!t1 && !t2)
1159 ret = -1;
1160
1161 odhcp6c_clear_state(STATE_SERVER_ADDR);
1162 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1163 }
1164 }
1165 break;
1166
1167 case DHCPV6_MSG_INFO_REQ:
1168 if (ret > 0) {
1169 // All server candidates can be cleared if not yet bound
1170 if (!odhcp6c_is_bound())
1171 dhcpv6_clear_all_server_cand();
1172
1173 t1 = refresh;
1174 }
1175 break;
1176
1177 default:
1178 break;
1179 }
1180
1181 return ret;
1182 }
1183
1184 static int dhcpv6_parse_ia(void *opt, void *end)
1185 {
1186 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1187 int parsed_ia = 0;
1188 uint32_t t1, t2;
1189 uint16_t otype, olen;
1190 uint8_t *odata;
1191
1192 t1 = ntohl(ia_hdr->t1);
1193 t2 = ntohl(ia_hdr->t2);
1194
1195 if (t1 > t2)
1196 return 0;
1197
1198 // Update address IA
1199 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1200 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1201 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1202
1203 entry.iaid = ia_hdr->iaid;
1204
1205 if (otype == DHCPV6_OPT_IA_PREFIX) {
1206 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1207 if (olen + 4U < sizeof(*prefix))
1208 continue;
1209
1210 entry.valid = ntohl(prefix->valid);
1211 entry.preferred = ntohl(prefix->preferred);
1212
1213 if (entry.preferred > entry.valid)
1214 continue;
1215
1216 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1217 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1218 if (entry.t1 > entry.t2)
1219 entry.t1 = entry.t2;
1220
1221 entry.length = prefix->prefix;
1222 entry.target = prefix->addr;
1223 uint16_t stype, slen;
1224 uint8_t *sdata;
1225
1226 // Parse PD-exclude
1227 bool ok = true;
1228 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1229 odata + olen, stype, slen, sdata) {
1230 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1231 continue;
1232
1233 uint8_t elen = sdata[0];
1234 if (elen > 64)
1235 elen = 64;
1236
1237 if (entry.length < 32 || elen <= entry.length) {
1238 ok = false;
1239 continue;
1240 }
1241
1242 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1243 if (slen <= bytes) {
1244 ok = false;
1245 continue;
1246 }
1247
1248 uint32_t exclude = 0;
1249 do {
1250 exclude = exclude << 8 | sdata[bytes];
1251 } while (--bytes);
1252
1253 exclude >>= 8 - ((elen - entry.length) % 8);
1254 exclude <<= 64 - elen;
1255
1256 // Abusing router & priority fields for exclusion
1257 entry.router = entry.target;
1258 entry.router.s6_addr32[1] |= htonl(exclude);
1259 entry.priority = elen;
1260 }
1261
1262 if (ok) {
1263 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0);
1264 parsed_ia++;
1265 }
1266
1267 entry.priority = 0;
1268 memset(&entry.router, 0, sizeof(entry.router));
1269 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1270 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1271 if (olen + 4U < sizeof(*addr))
1272 continue;
1273
1274 entry.preferred = ntohl(addr->preferred);
1275 entry.valid = ntohl(addr->valid);
1276
1277 if (entry.preferred > entry.valid)
1278 continue;
1279
1280 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1281 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1282 if (entry.t1 > entry.t2)
1283 entry.t1 = entry.t2;
1284
1285 entry.length = 128;
1286 entry.target = addr->addr;
1287
1288 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0);
1289 parsed_ia++;
1290 }
1291 }
1292 return parsed_ia;
1293 }
1294
1295 static int dhcpv6_calc_refresh_timers(void)
1296 {
1297 struct odhcp6c_entry *e;
1298 size_t ia_na_entries, ia_pd_entries, i;
1299 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1300
1301 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1302 ia_na_entries /= sizeof(*e);
1303
1304 for (i = 0; i < ia_na_entries; i++) {
1305 if (e[i].t1 < l_t1)
1306 l_t1 = e[i].t1;
1307
1308 if (e[i].t2 < l_t2)
1309 l_t2 = e[i].t2;
1310
1311 if (e[i].valid > l_t3)
1312 l_t3 = e[i].valid;
1313 }
1314
1315 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1316 ia_pd_entries /= sizeof(*e);
1317
1318 for (i = 0; i < ia_pd_entries; i++) {
1319 if (e[i].t1 < l_t1)
1320 l_t1 = e[i].t1;
1321
1322 if (e[i].t2 < l_t2)
1323 l_t2 = e[i].t2;
1324
1325 if (e[i].valid > l_t3)
1326 l_t3 = e[i].valid;
1327 }
1328
1329 if (ia_pd_entries || ia_na_entries) {
1330 t1 = l_t1;
1331 t2 = l_t2;
1332 t3 = l_t3;
1333 }
1334
1335 return (int)(ia_pd_entries + ia_na_entries);
1336 }
1337
1338 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1339 const void *status_msg, int len)
1340 {
1341 const char *src = status_msg;
1342 char buf[len + 3];
1343 char *dst = buf;
1344
1345 if (len) {
1346 *dst++ = '(';
1347 while (len--) {
1348 *dst = isprint((unsigned char)*src) ? *src : '?';
1349 src++;
1350 dst++;
1351 }
1352 *dst++ = ')';
1353 }
1354
1355 *dst = 0;
1356
1357 syslog(LOG_WARNING, "Server returned %s status %i %s",
1358 scope, code, buf);
1359 }
1360
1361 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1362 const uint16_t code, const void *status_msg, const int len,
1363 int *ret)
1364 {
1365 dhcpv6_log_status_code(code, "message", status_msg, len);
1366
1367 switch (code) {
1368 case DHCPV6_UnspecFail:
1369 // Generic failure
1370 *ret = 0;
1371 break;
1372
1373 case DHCPV6_UseMulticast:
1374 switch(orig) {
1375 case DHCPV6_MSG_REQUEST:
1376 case DHCPV6_MSG_RENEW:
1377 case DHCPV6_MSG_RELEASE:
1378 case DHCPV6_MSG_DECLINE:
1379 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1380 server_addr = in6addr_any;
1381 *ret = 0;
1382 break;
1383 default:
1384 break;
1385 }
1386 break;
1387
1388 case DHCPV6_NoAddrsAvail:
1389 case DHCPV6_NoPrefixAvail:
1390 if (orig == DHCPV6_MSG_REQUEST)
1391 *ret = 0; // Failure
1392 break;
1393
1394 default:
1395 break;
1396 }
1397 }
1398
1399 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1400 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1401 const void *status_msg, const int len,
1402 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1403 {
1404 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1405 "IA_NA" : "IA_PD", status_msg, len);
1406
1407 switch (code) {
1408 case DHCPV6_NoBinding:
1409 switch (orig) {
1410 case DHCPV6_MSG_RENEW:
1411 case DHCPV6_MSG_REBIND:
1412 if ((*ret > 0) && !handled_status_codes[code])
1413 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1414 break;
1415
1416 default:
1417 break;
1418 }
1419 break;
1420
1421 default:
1422 *ret = 0;
1423 break;
1424 }
1425 }
1426
1427 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1428 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1429 {
1430 size_t cand_len, i;
1431 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1432
1433 // Remove identical duid server candidate
1434 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1435 if (cand->duid_len == c[i].duid_len &&
1436 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1437 free(c[i].ia_na);
1438 free(c[i].ia_pd);
1439 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1440 break;
1441 }
1442 }
1443
1444 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1445 i < cand_len / sizeof(*c); ++i) {
1446 if (c[i].preference < cand->preference)
1447 break;
1448 }
1449
1450 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1451 free(cand->ia_na);
1452 free(cand->ia_pd);
1453 }
1454 }
1455
1456 static void dhcpv6_clear_all_server_cand(void)
1457 {
1458 size_t cand_len, i;
1459 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1460
1461 // Server candidates need deep delete for IA_NA/IA_PD
1462 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1463 free(c[i].ia_na);
1464 free(c[i].ia_pd);
1465 }
1466 odhcp6c_clear_state(STATE_SERVER_CAND);
1467 }
1468
1469 int dhcpv6_promote_server_cand(void)
1470 {
1471 size_t cand_len;
1472 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1473 uint16_t hdr[2];
1474 int ret = DHCPV6_STATELESS;
1475
1476 // Clear lingering candidate state info
1477 odhcp6c_clear_state(STATE_SERVER_ID);
1478 odhcp6c_clear_state(STATE_IA_NA);
1479 odhcp6c_clear_state(STATE_IA_PD);
1480
1481 if (!cand_len)
1482 return -1;
1483
1484 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1485 na_mode = IA_MODE_NONE;
1486
1487 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1488 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1489
1490 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1491 }
1492
1493 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1494 hdr[1] = htons(cand->duid_len);
1495 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1496 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1497 accept_reconfig = cand->wants_reconfigure;
1498
1499 if (cand->ia_na_len) {
1500 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1501 free(cand->ia_na);
1502 if (na_mode != IA_MODE_NONE)
1503 ret = DHCPV6_STATEFUL;
1504 }
1505
1506 if (cand->ia_pd_len) {
1507 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1508 free(cand->ia_pd);
1509 if (request_prefix)
1510 ret = DHCPV6_STATEFUL;
1511 }
1512
1513 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1514 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1515
1516 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1517
1518 return ret;
1519 }
Openwrt DHCPv6 Client