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dhcpv6: initialize ifreq struct
[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 memset(&ifr, 0, sizeof(ifr));
138 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
139 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
140 return -1;
141
142 ifindex = ifr.ifr_ifindex;
143
144 // Create client DUID
145 size_t client_id_len;
146 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
147 if (client_id_len == 0) {
148 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
149 DHCPV6_DUID_LLADDR, 0, 1};
150
151 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
152 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
153
154 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
155 struct ifreq ifs[100], *ifp, *ifend;
156 struct ifconf ifc;
157 ifc.ifc_req = ifs;
158 ifc.ifc_len = sizeof(ifs);
159
160 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
161 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
162 // If our interface doesn't have an address...
163 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
164 for (ifp = ifc.ifc_req; ifp < ifend &&
165 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
166 memcpy(ifr.ifr_name, ifp->ifr_name,
167 sizeof(ifr.ifr_name));
168 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
169 continue;
170
171 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
172 ETHER_ADDR_LEN);
173 }
174 }
175
176 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
177 }
178
179 // Create ORO
180 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
181 uint16_t oro[] = {
182 htons(DHCPV6_OPT_SIP_SERVER_D),
183 htons(DHCPV6_OPT_SIP_SERVER_A),
184 htons(DHCPV6_OPT_DNS_SERVERS),
185 htons(DHCPV6_OPT_DNS_DOMAIN),
186 htons(DHCPV6_OPT_UNICAST),
187 htons(DHCPV6_OPT_SNTP_SERVERS),
188 htons(DHCPV6_OPT_NTP_SERVER),
189 htons(DHCPV6_OPT_AFTR_NAME),
190 htons(DHCPV6_OPT_PD_EXCLUDE),
191 htons(DHCPV6_OPT_SOL_MAX_RT),
192 htons(DHCPV6_OPT_INF_MAX_RT),
193 #ifdef EXT_CER_ID
194 htons(DHCPV6_OPT_CER_ID),
195 #endif
196 htons(DHCPV6_OPT_S46_CONT_MAPE),
197 htons(DHCPV6_OPT_S46_CONT_MAPT),
198 htons(DHCPV6_OPT_S46_CONT_LW),
199 };
200 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
201 }
202
203 // Configure IPv6-options
204 int val = 1;
205 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
206 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
207 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
208 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
209
210 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
211 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
212
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_OPTS,
226 IOV_RECONF_ACCEPT,
227 IOV_FQDN,
228 IOV_HDR_IA_NA,
229 IOV_IA_NA,
230 IOV_IA_PD,
231 IOV_TOTAL
232 };
233
234 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
235 {
236 int mode = DHCPV6_UNKNOWN;
237
238 na_mode = na;
239 pd_mode = pd;
240
241 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
242 mode = DHCPV6_STATELESS;
243 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
244 mode = DHCPV6_STATEFUL;
245
246 return mode;
247 }
248
249 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
250 {
251 // Build FQDN
252 char fqdn_buf[256];
253 gethostname(fqdn_buf, sizeof(fqdn_buf));
254 struct {
255 uint16_t type;
256 uint16_t len;
257 uint8_t flags;
258 uint8_t data[256];
259 } fqdn;
260 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
261 sizeof(fqdn.data), NULL, NULL);
262 fqdn.type = htons(DHCPV6_OPT_FQDN);
263 fqdn.len = htons(fqdn_len - 4);
264 fqdn.flags = 0;
265
266 // Build Client ID
267 size_t cl_id_len;
268 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
269
270 // Get Server ID
271 size_t srv_id_len;
272 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
273
274 // Build IA_PDs
275 size_t ia_pd_entries = 0, ia_pd_len = 0;
276 uint8_t *ia_pd;
277
278 if (type == DHCPV6_MSG_SOLICIT) {
279 odhcp6c_clear_state(STATE_IA_PD);
280 size_t n_prefixes;
281 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
282 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
283
284 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
285
286 for (size_t i = 0; i < n_prefixes; i++) {
287 struct dhcpv6_ia_hdr hdr_ia_pd = {
288 htons(DHCPV6_OPT_IA_PD),
289 htons(sizeof(hdr_ia_pd) - 4 +
290 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
291 request_prefixes[i].iaid, 0, 0
292 };
293 struct dhcpv6_ia_prefix pref = {
294 .type = htons(DHCPV6_OPT_IA_PREFIX),
295 .len = htons(sizeof(pref) - 4),
296 .prefix = request_prefixes[i].length
297 };
298 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
299 ia_pd_len += sizeof(hdr_ia_pd);
300 if (request_prefixes[i].length) {
301 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
302 ia_pd_len += sizeof(pref);
303 }
304 }
305 } else {
306 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
307 ia_pd_entries /= sizeof(*e);
308
309 // we're too lazy to count our distinct IAIDs,
310 // so just allocate maximally needed space
311 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
312 sizeof(struct dhcpv6_ia_hdr)));
313
314 for (size_t i = 0; i < ia_pd_entries; ++i) {
315 uint32_t iaid = e[i].iaid;
316
317 // check if this is an unprocessed IAID and skip if not.
318 int new_iaid = 1;
319 for (int j = i-1; j >= 0; j--) {
320 if (e[j].iaid == iaid) {
321 new_iaid = 0;
322 break;
323 }
324 }
325
326 if (!new_iaid)
327 continue;
328
329 // construct header
330 struct dhcpv6_ia_hdr hdr_ia_pd = {
331 htons(DHCPV6_OPT_IA_PD),
332 htons(sizeof(hdr_ia_pd) - 4),
333 iaid, 0, 0
334 };
335
336 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
337 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
338 ia_pd_len += sizeof(hdr_ia_pd);
339
340 for (size_t j = i; j < ia_pd_entries; j++) {
341 if (e[j].iaid != iaid)
342 continue;
343
344 uint8_t ex_len = 0;
345 if (e[j].priority > 0)
346 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
347
348 struct dhcpv6_ia_prefix p = {
349 .type = htons(DHCPV6_OPT_IA_PREFIX),
350 .len = htons(sizeof(p) - 4U + ex_len),
351 .prefix = e[j].length,
352 .addr = e[j].target
353 };
354
355 if (type == DHCPV6_MSG_REQUEST) {
356 p.preferred = htonl(e[j].preferred);
357 p.valid = htonl(e[j].valid);
358 }
359
360 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
361 ia_pd_len += sizeof(p);
362
363 if (ex_len) {
364 ia_pd[ia_pd_len++] = 0;
365 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
366 ia_pd[ia_pd_len++] = 0;
367 ia_pd[ia_pd_len++] = ex_len - 4;
368 ia_pd[ia_pd_len++] = e[j].priority;
369
370 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
371 excl >>= (64 - e[j].priority);
372 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
373
374 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
375 ia_pd[ia_pd_len + i] = excl & 0xff;
376 ia_pd_len += ex_len - 5;
377 }
378
379 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
380 }
381 }
382 }
383
384 if (ia_pd_entries > 0)
385 request_prefix = 1;
386
387 // Build IA_NAs
388 size_t ia_na_entries, ia_na_len = 0;
389 void *ia_na = NULL;
390 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
391 ia_na_entries /= sizeof(*e);
392
393 struct dhcpv6_ia_hdr hdr_ia_na = {
394 htons(DHCPV6_OPT_IA_NA),
395 htons(sizeof(hdr_ia_na) - 4),
396 htonl(1), 0, 0
397 };
398
399 struct dhcpv6_ia_addr pa[ia_na_entries];
400 for (size_t i = 0; i < ia_na_entries; ++i) {
401 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
402 pa[i].len = htons(sizeof(pa[i]) - 4U);
403 pa[i].addr = e[i].target;
404
405 if (type == DHCPV6_MSG_REQUEST) {
406 pa[i].preferred = htonl(e[i].preferred);
407 pa[i].valid = htonl(e[i].valid);
408 } else {
409 pa[i].preferred = 0;
410 pa[i].valid = 0;
411 }
412 }
413
414 ia_na = pa;
415 ia_na_len = sizeof(pa);
416 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
417
418 // Reconfigure Accept
419 struct {
420 uint16_t type;
421 uint16_t length;
422 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
423
424 // Request Information Refresh
425 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
426
427 // Option list
428 size_t opts_len;
429 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
430
431 // Prepare Header
432 size_t oro_len;
433 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
434 struct {
435 uint8_t type;
436 uint8_t trid[3];
437 uint16_t elapsed_type;
438 uint16_t elapsed_len;
439 uint16_t elapsed_value;
440 uint16_t oro_type;
441 uint16_t oro_len;
442 } hdr = {
443 type, {trid[0], trid[1], trid[2]},
444 htons(DHCPV6_OPT_ELAPSED), htons(2),
445 htons((ecs > 0xffff) ? 0xffff : ecs),
446 htons(DHCPV6_OPT_ORO), htons(oro_len),
447 };
448
449 struct iovec iov[IOV_TOTAL] = {
450 [IOV_HDR] = {&hdr, sizeof(hdr)},
451 [IOV_ORO] = {oro, oro_len},
452 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
453 [IOV_CL_ID] = {cl_id, cl_id_len},
454 [IOV_SRV_ID] = {srv_id, srv_id_len},
455 [IOV_OPTS] = { opts, opts_len },
456 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
457 [IOV_FQDN] = {&fqdn, fqdn_len},
458 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
459 [IOV_IA_NA] = {ia_na, ia_na_len},
460 [IOV_IA_PD] = {ia_pd, ia_pd_len},
461 };
462
463 size_t cnt = IOV_TOTAL;
464 if (type == DHCPV6_MSG_INFO_REQ) {
465 cnt = 9;
466 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
467 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
468 } else if (!request_prefix)
469 cnt = 13;
470
471 // Disable IAs if not used
472 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
473 iov[IOV_HDR_IA_NA].iov_len = 0;
474
475 if (na_mode == IA_MODE_NONE)
476 iov[IOV_HDR_IA_NA].iov_len = 0;
477
478 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
479 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
480 iov[IOV_RECONF_ACCEPT].iov_len = 0;
481
482 if (!(client_options & DHCPV6_CLIENT_FQDN))
483 iov[IOV_FQDN].iov_len = 0;
484
485 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
486 0, ALL_DHCPV6_RELAYS, ifindex};
487 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
488 .msg_iov = iov, .msg_iovlen = cnt};
489
490 switch (type) {
491 case DHCPV6_MSG_REQUEST:
492 case DHCPV6_MSG_RENEW:
493 case DHCPV6_MSG_RELEASE:
494 case DHCPV6_MSG_DECLINE:
495 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
496 odhcp6c_addr_in_scope(&server_addr)) {
497 srv.sin6_addr = server_addr;
498 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
499 srv.sin6_scope_id = 0;
500 }
501 break;
502 default:
503 break;
504 }
505
506 if (sendmsg(sock, &msg, 0) < 0) {
507 char in6_str[INET6_ADDRSTRLEN];
508
509 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
510 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
511 in6_str, sizeof(in6_str)), strerror(errno));
512 }
513 }
514
515 static int64_t dhcpv6_rand_delay(int64_t time)
516 {
517 int random;
518 odhcp6c_random(&random, sizeof(random));
519
520 return (time * ((int64_t)random % 1000LL)) / 10000LL;
521 }
522
523 int dhcpv6_request(enum dhcpv6_msg type)
524 {
525 uint8_t rc = 0;
526 uint64_t timeout = UINT32_MAX;
527 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
528
529 if (retx->delay) {
530 struct timespec ts = {0, 0};
531 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
532
533 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
534 }
535
536 if (type == DHCPV6_MSG_UNKNOWN)
537 timeout = t1;
538 else if (type == DHCPV6_MSG_RENEW)
539 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
540 else if (type == DHCPV6_MSG_REBIND)
541 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
542
543 if (timeout == 0)
544 return -1;
545
546 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
547 retx->name, timeout, retx->max_rc);
548
549 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
550
551 // Generate transaction ID
552 uint8_t trid[3] = {0, 0, 0};
553 if (type != DHCPV6_MSG_UNKNOWN)
554 odhcp6c_random(trid, sizeof(trid));
555
556 ssize_t len = -1;
557 int64_t rto = 0;
558
559 do {
560 if (rto == 0) {
561 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
562
563 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
564 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
565 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
566
567 rto = (retx->init_timeo * 1000 + delay);
568 } else
569 rto = (2 * rto + dhcpv6_rand_delay(rto));
570
571 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
572 rto = retx->max_timeo * 1000 +
573 dhcpv6_rand_delay(retx->max_timeo * 1000);
574
575 // Calculate end for this round and elapsed time
576 uint64_t round_end = round_start + rto;
577 elapsed = round_start - start;
578
579 // Don't wait too long if timeout differs from infinite
580 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
581 round_end = timeout * 1000 + start;
582
583 // Built and send package
584 switch (type) {
585 case DHCPV6_MSG_UNKNOWN:
586 break;
587 default:
588 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
589 retx->name, elapsed, rc);
590 // Fall through
591 case DHCPV6_MSG_SOLICIT:
592 case DHCPV6_MSG_INFO_REQ:
593 dhcpv6_send(type, trid, elapsed / 10);
594 rc++;
595 }
596
597 // Receive rounds
598 for (; len < 0 && (round_start < round_end);
599 round_start = odhcp6c_get_milli_time()) {
600 uint8_t buf[1536];
601 union {
602 struct cmsghdr hdr;
603 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
604 } cmsg_buf;
605 struct iovec iov = {buf, sizeof(buf)};
606 struct sockaddr_in6 addr;
607 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
608 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
609 .msg_controllen = sizeof(cmsg_buf)};
610 struct in6_pktinfo *pktinfo = NULL;
611
612 // Check for pending signal
613 if (odhcp6c_signal_process())
614 return -1;
615
616 // Set timeout for receiving
617 uint64_t t = round_end - round_start;
618 struct timeval tv = {t / 1000, (t % 1000) * 1000};
619 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
620 &tv, sizeof(tv));
621
622 // Receive cycle
623 len = recvmsg(sock, &msg, 0);
624 if (len < 0)
625 continue;
626
627 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
628 ch = CMSG_NXTHDR(&msg, ch)) {
629 if (ch->cmsg_level == SOL_IPV6 &&
630 ch->cmsg_type == IPV6_PKTINFO) {
631 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
632 break;
633 }
634 }
635
636 if (pktinfo == NULL) {
637 len = -1;
638 continue;
639 }
640
641 if (!dhcpv6_response_is_valid(buf, len, trid,
642 type, &pktinfo->ipi6_addr)) {
643 len = -1;
644 continue;
645 }
646
647 uint8_t *opt = &buf[4];
648 uint8_t *opt_end = opt + len - 4;
649
650 round_start = odhcp6c_get_milli_time();
651 elapsed = round_start - start;
652 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
653 elapsed);
654
655 if (retx->handler_reply)
656 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
657
658 if (len > 0 && round_end - round_start > 1000)
659 round_end = 1000 + round_start;
660 }
661
662 // Allow
663 if (retx->handler_finish)
664 len = retx->handler_finish();
665 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
666 (!retx->max_rc || rc < retx->max_rc));
667 return len;
668 }
669
670 // Message validation checks according to RFC3315 chapter 15
671 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
672 const uint8_t transaction[3], enum dhcpv6_msg type,
673 const struct in6_addr *daddr)
674 {
675 const struct dhcpv6_header *rep = buf;
676 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
677 transaction, sizeof(rep->tr_id)))
678 return false; // Invalid reply
679
680 if (type == DHCPV6_MSG_SOLICIT) {
681 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
682 rep->msg_type != DHCPV6_MSG_REPLY)
683 return false;
684
685 } else if (type == DHCPV6_MSG_UNKNOWN) {
686 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
687 return false;
688
689 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
690 return false;
691
692 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
693 rcmsg = DHCPV6_MSG_UNKNOWN;
694 uint16_t otype, olen = UINT16_MAX;
695 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
696 ia_present = false, options_valid = true;
697
698 size_t client_id_len, server_id_len;
699 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
700 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
701
702 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
703 if (otype == DHCPV6_OPT_CLIENTID) {
704 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
705 &odata[-4], client_id, client_id_len);
706 } else if (otype == DHCPV6_OPT_SERVERID) {
707 if (server_id_len)
708 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
709 &odata[-4], server_id, server_id_len);
710 else
711 serverid_ok = true;
712 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
713 sizeof(struct dhcpv6_auth_reconfigure)) {
714 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
715 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
716 continue;
717
718 md5_ctx_t md5;
719 uint8_t serverhash[16], secretbytes[64];
720 uint32_t hash[4];
721 memcpy(serverhash, r->key, sizeof(serverhash));
722 memset(r->key, 0, sizeof(r->key));
723
724 memset(secretbytes, 0, sizeof(secretbytes));
725 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
726
727 for (size_t i = 0; i < sizeof(secretbytes); ++i)
728 secretbytes[i] ^= 0x36;
729
730 md5_begin(&md5);
731 md5_hash(secretbytes, sizeof(secretbytes), &md5);
732 md5_hash(buf, len, &md5);
733 md5_end(hash, &md5);
734
735 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
736 secretbytes[i] ^= 0x36;
737 secretbytes[i] ^= 0x5c;
738 }
739
740 md5_begin(&md5);
741 md5_hash(secretbytes, sizeof(secretbytes), &md5);
742 md5_hash(hash, 16, &md5);
743 md5_end(hash, &md5);
744
745 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
746 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
747 rcmsg = odata[0];
748 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
749 ia_present = true;
750 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
751 options_valid = false;
752 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
753 (otype == DHCPV6_OPT_PD_EXCLUDE))
754 // Options are not allowed on global level
755 options_valid = false;
756 }
757
758 if (!options_valid || ((odata + olen) > end))
759 return false;
760
761 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
762 return false;
763
764 if (rep->msg_type == DHCPV6_MSG_RECONF) {
765 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
766 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
767 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
768 return false;
769 }
770
771 return clientid_ok && serverid_ok;
772 }
773
774 int dhcpv6_poll_reconfigure(void)
775 {
776 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
777
778 if (ret != -1)
779 ret = dhcpv6_request(ret);
780
781 return ret;
782 }
783
784 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
785 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
786 {
787 uint16_t otype, olen;
788 uint8_t *odata;
789 int msg = -1;
790
791 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
792 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
793 switch (odata[0]) {
794 case DHCPV6_MSG_REBIND:
795 if (t2 != UINT32_MAX)
796 t2 = 0;
797 // Fall through
798 case DHCPV6_MSG_RENEW:
799 if (t1 != UINT32_MAX)
800 t1 = 0;
801 // Fall through
802 case DHCPV6_MSG_INFO_REQ:
803 msg = odata[0];
804 break;
805
806 default:
807 break;
808 }
809 }
810 }
811
812 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
813
814 return msg;
815 }
816
817 // Collect all advertised servers
818 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
819 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
820 {
821 uint16_t olen, otype;
822 uint8_t *odata, pref = 0;
823 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
824 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
825 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
826 bool have_na = false;
827 int have_pd = 0;
828
829 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
830 if (orig == DHCPV6_MSG_SOLICIT &&
831 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
832 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
833 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
834 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
835 }
836
837 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
838 memcpy(cand.duid, odata, olen);
839 cand.duid_len = olen;
840 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
841 cand.preference >= 0) {
842 cand.preference = pref = odata[0];
843 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
844 cand.server_addr = *(struct in6_addr *)odata;
845 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
846 cand.wants_reconfigure = true;
847 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
848 uint32_t sol_max_rt = ntohl_unaligned(odata);
849 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
850 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
851 cand.sol_max_rt = sol_max_rt;
852
853 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
854 uint32_t inf_max_rt = ntohl_unaligned(odata);
855 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
856 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
857 cand.inf_max_rt = inf_max_rt;
858
859 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
860 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
861 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
862 uint8_t *oend = odata + olen, *d;
863 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
864 if (otype == DHCPV6_OPT_IA_PREFIX &&
865 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
866 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
867 have_pd = p->prefix;
868 }
869 }
870 } else if (otype == DHCPV6_OPT_IA_NA &&
871 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
872 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
873 uint8_t *oend = odata + olen, *d;
874
875 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
876 if (otype == DHCPV6_OPT_IA_ADDR &&
877 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
878 have_na = true;
879 }
880 }
881 }
882
883 if ((!have_na && na_mode == IA_MODE_FORCE) ||
884 (!have_pd && pd_mode == IA_MODE_FORCE)) {
885 /*
886 * RFC7083 states to process the SOL_MAX_RT and
887 * INF_MAX_RT options even if the DHCPv6 server
888 * did not propose any IA_NA and/or IA_PD
889 */
890 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
891 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
892 return -1;
893 }
894
895 if (na_mode != IA_MODE_NONE && !have_na) {
896 cand.has_noaddravail = true;
897 cand.preference -= 1000;
898 }
899
900 if (pd_mode != IA_MODE_NONE) {
901 if (have_pd)
902 cand.preference += 2000 + (128 - have_pd);
903 else
904 cand.preference -= 2000;
905 }
906
907 if (cand.duid_len > 0) {
908 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
909 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
910 dhcpv6_add_server_cand(&cand);
911 }
912
913 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
914 }
915
916 static int dhcpv6_commit_advert(void)
917 {
918 return dhcpv6_promote_server_cand();
919 }
920
921 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
922 const void *opt, const void *end, const struct sockaddr_in6 *from)
923 {
924 dhcpv6_handle_advert(orig, rc, opt, end, from);
925 if (dhcpv6_commit_advert() < 0)
926 return -1;
927
928 return dhcpv6_handle_reply(orig, rc, opt, end, from);
929 }
930
931 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
932 const void *opt, const void *end, const struct sockaddr_in6 *from)
933 {
934 uint8_t *odata;
935 uint16_t otype, olen;
936 uint32_t refresh = 86400;
937 int ret = 1;
938 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
939
940 odhcp6c_expire();
941
942 if (orig == DHCPV6_MSG_UNKNOWN) {
943 static time_t last_update = 0;
944 time_t now = odhcp6c_get_milli_time() / 1000;
945
946 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
947 last_update = now;
948
949 if (t1 != UINT32_MAX)
950 t1 -= elapsed;
951
952 if (t2 != UINT32_MAX)
953 t2 -= elapsed;
954
955 if (t3 != UINT32_MAX)
956 t3 -= elapsed;
957
958 if (t1 < 0)
959 t1 = 0;
960
961 if (t2 < 0)
962 t2 = 0;
963
964 if (t3 < 0)
965 t3 = 0;
966 }
967
968 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
969 // Delete NA and PD we have in the state from the Advert
970 odhcp6c_clear_state(STATE_IA_NA);
971 odhcp6c_clear_state(STATE_IA_PD);
972 }
973
974 if (opt) {
975 odhcp6c_clear_state(STATE_DNS);
976 odhcp6c_clear_state(STATE_SEARCH);
977 odhcp6c_clear_state(STATE_SNTP_IP);
978 odhcp6c_clear_state(STATE_NTP_IP);
979 odhcp6c_clear_state(STATE_NTP_FQDN);
980 odhcp6c_clear_state(STATE_SIP_IP);
981 odhcp6c_clear_state(STATE_SIP_FQDN);
982 odhcp6c_clear_state(STATE_AFTR_NAME);
983 odhcp6c_clear_state(STATE_CER);
984 odhcp6c_clear_state(STATE_S46_MAPT);
985 odhcp6c_clear_state(STATE_S46_MAPE);
986 odhcp6c_clear_state(STATE_S46_LW);
987 odhcp6c_clear_state(STATE_PASSTHRU);
988 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
989
990 // Parse and find all matching IAs
991 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
992 struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
993
994 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
995 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
996 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
997
998 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
999 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1000 continue;
1001
1002 // Test ID
1003 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1004 continue;
1005
1006 uint16_t code = DHCPV6_Success;
1007 uint16_t stype, slen;
1008 uint8_t *sdata;
1009 // Get and handle status code
1010 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1011 stype, slen, sdata) {
1012 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1013 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1014 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1015
1016 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1017
1018 if (code == DHCPV6_Success)
1019 continue;
1020
1021 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1022 code, mdata, mlen, handled_status_codes, &ret);
1023
1024 if (ret > 0)
1025 return ret;
1026
1027 break;
1028 }
1029 }
1030
1031 if (code != DHCPV6_Success)
1032 continue;
1033
1034 dhcpv6_parse_ia(ia_hdr, odata + olen);
1035 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr))
1036 server_addr = *(struct in6_addr *)odata;
1037 else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1038 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1039 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1040 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1041
1042 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1043 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1044 if (olen % 16 == 0)
1045 odhcp6c_add_state(STATE_DNS, odata, olen);
1046 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1047 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1048 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1049 if (olen % 16 == 0)
1050 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1051 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1052 uint16_t stype, slen;
1053 uint8_t *sdata;
1054 // Test status and bail if error
1055 dhcpv6_for_each_option(odata, odata + olen,
1056 stype, slen, sdata) {
1057 if (slen == 16 && (stype == NTP_MC_ADDR ||
1058 stype == NTP_SRV_ADDR))
1059 odhcp6c_add_state(STATE_NTP_IP,
1060 sdata, slen);
1061 else if (slen > 0 && stype == NTP_SRV_FQDN)
1062 odhcp6c_add_state(STATE_NTP_FQDN,
1063 sdata, slen);
1064 }
1065 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1066 if (olen == 16)
1067 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1068 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1069 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1070 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1071 refresh = ntohl_unaligned(odata);
1072 } else if (otype == DHCPV6_OPT_AUTH) {
1073 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1074 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1075 if (r->protocol == 3 && r->algorithm == 1 &&
1076 r->reconf_type == 1)
1077 memcpy(reconf_key, r->key, sizeof(r->key));
1078 }
1079 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1080 size_t cur_len;
1081 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1082 if (cur_len == 0)
1083 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1084 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1085 uint32_t sol_max_rt = ntohl_unaligned(odata);
1086 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1087 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1088 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1089 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1090 uint32_t inf_max_rt = ntohl_unaligned(odata);
1091 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1092 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1093 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1094 #ifdef EXT_CER_ID
1095 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1096 sizeof(struct dhcpv6_cer_id)) {
1097 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1098 struct in6_addr any = IN6ADDR_ANY_INIT;
1099 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1100 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1101 #endif
1102 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1103 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1104 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1105 size_t mape_len;
1106 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1107 if (mape_len == 0)
1108 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1109 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1110 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1111 } else
1112 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1113
1114 if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1115 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1116 }
1117 }
1118
1119 switch (orig) {
1120 case DHCPV6_MSG_REQUEST:
1121 case DHCPV6_MSG_REBIND:
1122 case DHCPV6_MSG_RENEW:
1123 // Update refresh timers if no fatal status code was received
1124 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1125 if (orig == DHCPV6_MSG_REQUEST) {
1126 // All server candidates can be cleared if not yet bound
1127 if (!odhcp6c_is_bound())
1128 dhcpv6_clear_all_server_cand();
1129
1130 odhcp6c_clear_state(STATE_SERVER_ADDR);
1131 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1132 } else if (orig == DHCPV6_MSG_RENEW) {
1133 // Send further renews if T1 is not set
1134 if (!t1)
1135 ret = -1;
1136
1137 } else if (orig == DHCPV6_MSG_REBIND) {
1138 // Send further rebinds if T1 and T2 is not set
1139 if (!t1 && !t2)
1140 ret = -1;
1141
1142 odhcp6c_clear_state(STATE_SERVER_ADDR);
1143 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1144 }
1145 }
1146 break;
1147
1148 case DHCPV6_MSG_INFO_REQ:
1149 if (ret > 0) {
1150 // All server candidates can be cleared if not yet bound
1151 if (!odhcp6c_is_bound())
1152 dhcpv6_clear_all_server_cand();
1153
1154 t1 = refresh;
1155 }
1156 break;
1157
1158 default:
1159 break;
1160 }
1161
1162 return ret;
1163 }
1164
1165 static int dhcpv6_parse_ia(void *opt, void *end)
1166 {
1167 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1168 int parsed_ia = 0;
1169 uint32_t t1, t2;
1170 uint16_t otype, olen;
1171 uint8_t *odata;
1172
1173 t1 = ntohl(ia_hdr->t1);
1174 t2 = ntohl(ia_hdr->t2);
1175
1176 if (t1 > t2)
1177 return 0;
1178
1179 // Update address IA
1180 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1181 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1182 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1183
1184 entry.iaid = ia_hdr->iaid;
1185
1186 if (otype == DHCPV6_OPT_IA_PREFIX) {
1187 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1188 if (olen + 4U < sizeof(*prefix))
1189 continue;
1190
1191 entry.valid = ntohl(prefix->valid);
1192 entry.preferred = ntohl(prefix->preferred);
1193
1194 if (entry.preferred > entry.valid)
1195 continue;
1196
1197 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1198 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1199 if (entry.t1 > entry.t2)
1200 entry.t1 = entry.t2;
1201
1202 entry.length = prefix->prefix;
1203 entry.target = prefix->addr;
1204 uint16_t stype, slen;
1205 uint8_t *sdata;
1206
1207 // Parse PD-exclude
1208 bool ok = true;
1209 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1210 odata + olen, stype, slen, sdata) {
1211 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1212 continue;
1213
1214 uint8_t elen = sdata[0];
1215 if (elen > 64)
1216 elen = 64;
1217
1218 if (entry.length < 32 || elen <= entry.length) {
1219 ok = false;
1220 continue;
1221 }
1222
1223 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1224 if (slen <= bytes) {
1225 ok = false;
1226 continue;
1227 }
1228
1229 uint32_t exclude = 0;
1230 do {
1231 exclude = exclude << 8 | sdata[bytes];
1232 } while (--bytes);
1233
1234 exclude >>= 8 - ((elen - entry.length) % 8);
1235 exclude <<= 64 - elen;
1236
1237 // Abusing router & priority fields for exclusion
1238 entry.router = entry.target;
1239 entry.router.s6_addr32[1] |= htonl(exclude);
1240 entry.priority = elen;
1241 }
1242
1243 if (ok) {
1244 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0);
1245 parsed_ia++;
1246 }
1247
1248 entry.priority = 0;
1249 memset(&entry.router, 0, sizeof(entry.router));
1250 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1251 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1252 if (olen + 4U < sizeof(*addr))
1253 continue;
1254
1255 entry.preferred = ntohl(addr->preferred);
1256 entry.valid = ntohl(addr->valid);
1257
1258 if (entry.preferred > entry.valid)
1259 continue;
1260
1261 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1262 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1263 if (entry.t1 > entry.t2)
1264 entry.t1 = entry.t2;
1265
1266 entry.length = 128;
1267 entry.target = addr->addr;
1268
1269 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0);
1270 parsed_ia++;
1271 }
1272 }
1273 return parsed_ia;
1274 }
1275
1276 static int dhcpv6_calc_refresh_timers(void)
1277 {
1278 struct odhcp6c_entry *e;
1279 size_t ia_na_entries, ia_pd_entries, i;
1280 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1281
1282 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1283 ia_na_entries /= sizeof(*e);
1284
1285 for (i = 0; i < ia_na_entries; i++) {
1286 if (e[i].t1 < l_t1)
1287 l_t1 = e[i].t1;
1288
1289 if (e[i].t2 < l_t2)
1290 l_t2 = e[i].t2;
1291
1292 if (e[i].valid > l_t3)
1293 l_t3 = e[i].valid;
1294 }
1295
1296 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1297 ia_pd_entries /= sizeof(*e);
1298
1299 for (i = 0; i < ia_pd_entries; i++) {
1300 if (e[i].t1 < l_t1)
1301 l_t1 = e[i].t1;
1302
1303 if (e[i].t2 < l_t2)
1304 l_t2 = e[i].t2;
1305
1306 if (e[i].valid > l_t3)
1307 l_t3 = e[i].valid;
1308 }
1309
1310 if (ia_pd_entries || ia_na_entries) {
1311 t1 = l_t1;
1312 t2 = l_t2;
1313 t3 = l_t3;
1314 }
1315
1316 return (int)(ia_pd_entries + ia_na_entries);
1317 }
1318
1319 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1320 const void *status_msg, int len)
1321 {
1322 const char *src = status_msg;
1323 char buf[len + 3];
1324 char *dst = buf;
1325
1326 if (len) {
1327 *dst++ = '(';
1328 while (len--) {
1329 *dst = isprint((unsigned char)*src) ? *src : '?';
1330 src++;
1331 dst++;
1332 }
1333 *dst++ = ')';
1334 }
1335
1336 *dst = 0;
1337
1338 syslog(LOG_WARNING, "Server returned %s status %i %s",
1339 scope, code, buf);
1340 }
1341
1342 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1343 const uint16_t code, const void *status_msg, const int len,
1344 int *ret)
1345 {
1346 dhcpv6_log_status_code(code, "message", status_msg, len);
1347
1348 switch (code) {
1349 case DHCPV6_UnspecFail:
1350 // Generic failure
1351 *ret = 0;
1352 break;
1353
1354 case DHCPV6_UseMulticast:
1355 switch(orig) {
1356 case DHCPV6_MSG_REQUEST:
1357 case DHCPV6_MSG_RENEW:
1358 case DHCPV6_MSG_RELEASE:
1359 case DHCPV6_MSG_DECLINE:
1360 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1361 server_addr = in6addr_any;
1362 *ret = 0;
1363 break;
1364 default:
1365 break;
1366 }
1367 break;
1368
1369 case DHCPV6_NoAddrsAvail:
1370 case DHCPV6_NoPrefixAvail:
1371 if (orig == DHCPV6_MSG_REQUEST)
1372 *ret = 0; // Failure
1373 break;
1374
1375 default:
1376 break;
1377 }
1378 }
1379
1380 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1381 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1382 const void *status_msg, const int len,
1383 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1384 {
1385 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1386 "IA_NA" : "IA_PD", status_msg, len);
1387
1388 switch (code) {
1389 case DHCPV6_NoBinding:
1390 switch (orig) {
1391 case DHCPV6_MSG_RENEW:
1392 case DHCPV6_MSG_REBIND:
1393 if ((*ret > 0) && !handled_status_codes[code])
1394 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1395 break;
1396
1397 default:
1398 break;
1399 }
1400 break;
1401
1402 default:
1403 *ret = 0;
1404 break;
1405 }
1406 }
1407
1408 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1409 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1410 {
1411 size_t cand_len, i;
1412 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1413
1414 // Remove identical duid server candidate
1415 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1416 if (cand->duid_len == c[i].duid_len &&
1417 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1418 free(c[i].ia_na);
1419 free(c[i].ia_pd);
1420 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1421 break;
1422 }
1423 }
1424
1425 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1426 i < cand_len / sizeof(*c); ++i) {
1427 if (c[i].preference < cand->preference)
1428 break;
1429 }
1430
1431 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1432 free(cand->ia_na);
1433 free(cand->ia_pd);
1434 }
1435 }
1436
1437 static void dhcpv6_clear_all_server_cand(void)
1438 {
1439 size_t cand_len, i;
1440 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1441
1442 // Server candidates need deep delete for IA_NA/IA_PD
1443 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1444 free(c[i].ia_na);
1445 free(c[i].ia_pd);
1446 }
1447 odhcp6c_clear_state(STATE_SERVER_CAND);
1448 }
1449
1450 int dhcpv6_promote_server_cand(void)
1451 {
1452 size_t cand_len;
1453 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1454 uint16_t hdr[2];
1455 int ret = DHCPV6_STATELESS;
1456
1457 // Clear lingering candidate state info
1458 odhcp6c_clear_state(STATE_SERVER_ID);
1459 odhcp6c_clear_state(STATE_IA_NA);
1460 odhcp6c_clear_state(STATE_IA_PD);
1461
1462 if (!cand_len)
1463 return -1;
1464
1465 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1466 na_mode = IA_MODE_NONE;
1467
1468 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1469 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1470
1471 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1472 }
1473
1474 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1475 hdr[1] = htons(cand->duid_len);
1476 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1477 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1478 accept_reconfig = cand->wants_reconfigure;
1479
1480 if (cand->ia_na_len) {
1481 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1482 free(cand->ia_na);
1483 if (na_mode != IA_MODE_NONE)
1484 ret = DHCPV6_STATEFUL;
1485 }
1486
1487 if (cand->ia_pd_len) {
1488 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1489 free(cand->ia_pd);
1490 if (request_prefix)
1491 ret = DHCPV6_STATEFUL;
1492 }
1493
1494 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1495 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1496
1497 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1498
1499 return ret;
1500 }
Openwrt DHCPv6 Client