projects / project / odhcp6c.git / blob
? search:


08fe236f80db53b2ad785b87760778e38bed26eb
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15 #include <time.h>
16 #include <fcntl.h>
17 #include <errno.h>
18 #include <stdlib.h>
19 #include <signal.h>
20 #include <limits.h>
21 #include <resolv.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <syslog.h>
25 #include <stdbool.h>
26 #include <ctype.h>
27 #include <sys/time.h>
28 #include <sys/ioctl.h>
29 #include <sys/socket.h>
30 #include <netinet/in.h>
31
32 #include <net/if.h>
33 #include <net/ethernet.h>
34
35 #include "odhcp6c.h"
36 #include "md5.h"
37
38
39 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
40 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
41 #define DHCPV6_CLIENT_PORT 546
42 #define DHCPV6_SERVER_PORT 547
43 #define DHCPV6_DUID_LLADDR 3
44 #define DHCPV6_REQ_DELAY 1
45
46 #define DHCPV6_SOL_MAX_RT_MIN 60
47 #define DHCPV6_SOL_MAX_RT_MAX 86400
48 #define DHCPV6_INF_MAX_RT_MIN 60
49 #define DHCPV6_INF_MAX_RT_MAX 86400
50
51 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
52 const uint8_t transaction[3], enum dhcpv6_msg type,
53 const struct in6_addr *daddr);
54
55 static int dhcpv6_parse_ia(void *opt, void *end);
56
57 static int dhcpv6_calc_refresh_timers(void);
58 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
59 const uint16_t code, const void *status_msg, const int len,
60 int *ret);
61 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
62 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
63 const void *status_msg, const int len,
64 bool handled_status_codes[_DHCPV6_Status_Max],
65 int *ret);
66 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
67 static void dhcpv6_clear_all_server_cand(void);
68
69 static reply_handler dhcpv6_handle_reply;
70 static reply_handler dhcpv6_handle_advert;
71 static reply_handler dhcpv6_handle_rebind_reply;
72 static reply_handler dhcpv6_handle_reconfigure;
73 static int dhcpv6_commit_advert(void);
74
75
76
77 // RFC 3315 - 5.5 Timeout and Delay values
78 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
79 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
80 dhcpv6_handle_reconfigure, NULL},
81 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
82 dhcpv6_handle_advert, dhcpv6_commit_advert},
83 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
84 dhcpv6_handle_reply, NULL},
85 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
86 dhcpv6_handle_reply, NULL},
87 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
88 dhcpv6_handle_rebind_reply, NULL},
89 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
90 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
91 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
92 dhcpv6_handle_reply, NULL},
93 };
94
95
96 // Sockets
97 static int sock = -1;
98 static int ifindex = -1;
99 static int64_t t1 = 0, t2 = 0, t3 = 0;
100
101 // IA states
102 static int request_prefix = -1;
103 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
104 static bool accept_reconfig = false;
105
106 // Reconfigure key
107 static uint8_t reconf_key[16];
108
109 // client options
110 static unsigned int client_options = 0;
111
112
113 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
114 {
115 client_options = options;
116 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
117
118 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
119 if (sock < 0)
120 return -1;
121
122 // Detect interface
123 struct ifreq ifr;
124 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
125 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
126 return -1;
127 ifindex = ifr.ifr_ifindex;
128
129 // Create client DUID
130 size_t client_id_len;
131 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
132 if (client_id_len == 0) {
133 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
134 DHCPV6_DUID_LLADDR, 0, 1};
135
136 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
137 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
138
139 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
140 struct ifreq ifs[100], *ifp, *ifend;
141 struct ifconf ifc;
142 ifc.ifc_req = ifs;
143 ifc.ifc_len = sizeof(ifs);
144
145 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
146 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
147 // If our interface doesn't have an address...
148 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
149 for (ifp = ifc.ifc_req; ifp < ifend &&
150 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
151 memcpy(ifr.ifr_name, ifp->ifr_name,
152 sizeof(ifr.ifr_name));
153 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
154 continue;
155
156 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
157 ETHER_ADDR_LEN);
158 }
159 }
160
161 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
162 }
163
164 // Create ORO
165 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
166 uint16_t oro[] = {
167 htons(DHCPV6_OPT_SIP_SERVER_D),
168 htons(DHCPV6_OPT_SIP_SERVER_A),
169 htons(DHCPV6_OPT_DNS_SERVERS),
170 htons(DHCPV6_OPT_DNS_DOMAIN),
171 htons(DHCPV6_OPT_SNTP_SERVERS),
172 htons(DHCPV6_OPT_NTP_SERVER),
173 htons(DHCPV6_OPT_AFTR_NAME),
174 htons(DHCPV6_OPT_PD_EXCLUDE),
175 htons(DHCPV6_OPT_SOL_MAX_RT),
176 htons(DHCPV6_OPT_INF_MAX_RT),
177 #ifdef EXT_CER_ID
178 htons(DHCPV6_OPT_CER_ID),
179 #endif
180 htons(DHCPV6_OPT_S46_CONT_MAPE),
181 htons(DHCPV6_OPT_S46_CONT_MAPT),
182 htons(DHCPV6_OPT_S46_CONT_LW),
183 };
184 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
185 }
186
187 // Configure IPv6-options
188 int val = 1;
189 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
190 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
191 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
192 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
193
194 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
195 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
196 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
197 return -1;
198
199 return 0;
200 }
201
202 enum {
203 IOV_HDR=0,
204 IOV_ORO,
205 IOV_ORO_REFRESH,
206 IOV_CL_ID,
207 IOV_SRV_ID,
208 IOV_VENDOR_CLASS_HDR,
209 IOV_VENDOR_CLASS,
210 IOV_USER_CLASS_HDR,
211 IOV_USER_CLASS,
212 IOV_RECONF_ACCEPT,
213 IOV_FQDN,
214 IOV_HDR_IA_NA,
215 IOV_IA_NA,
216 IOV_IA_PD,
217 IOV_TOTAL
218 };
219
220 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
221 {
222 int mode = DHCPV6_UNKNOWN;
223
224 na_mode = na;
225 pd_mode = pd;
226
227 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
228 mode = DHCPV6_STATELESS;
229 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
230 mode = DHCPV6_STATEFUL;
231
232 return mode;
233 }
234
235 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
236 {
237 // Build FQDN
238 char fqdn_buf[256];
239 gethostname(fqdn_buf, sizeof(fqdn_buf));
240 struct {
241 uint16_t type;
242 uint16_t len;
243 uint8_t flags;
244 uint8_t data[256];
245 } fqdn;
246 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
247 sizeof(fqdn.data), NULL, NULL);
248 fqdn.type = htons(DHCPV6_OPT_FQDN);
249 fqdn.len = htons(fqdn_len - 4);
250 fqdn.flags = 0;
251
252
253 // Build Client ID
254 size_t cl_id_len;
255 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
256
257 // Get Server ID
258 size_t srv_id_len;
259 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
260
261 // Build IA_PDs
262 size_t ia_pd_entries = 0, ia_pd_len = 0;
263 uint8_t *ia_pd;
264
265 if (type == DHCPV6_MSG_SOLICIT) {
266 odhcp6c_clear_state(STATE_IA_PD);
267 size_t n_prefixes;
268 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
269 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
270
271 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
272
273 for (size_t i = 0; i < n_prefixes; i++) {
274 struct dhcpv6_ia_hdr hdr_ia_pd = {
275 htons(DHCPV6_OPT_IA_PD),
276 htons(sizeof(hdr_ia_pd) - 4 +
277 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
278 request_prefixes[i].iaid, 0, 0
279 };
280 struct dhcpv6_ia_prefix pref = {
281 .type = htons(DHCPV6_OPT_IA_PREFIX),
282 .len = htons(sizeof(pref) - 4),
283 .prefix = request_prefixes[i].length
284 };
285 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
286 ia_pd_len += sizeof(hdr_ia_pd);
287 if (request_prefixes[i].length) {
288 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
289 ia_pd_len += sizeof(pref);
290 }
291 }
292 } else {
293 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
294 ia_pd_entries /= sizeof(*e);
295
296 // we're too lazy to count our distinct IAIDs,
297 // so just allocate maximally needed space
298 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
299 sizeof(struct dhcpv6_ia_hdr)));
300
301 for (size_t i = 0; i < ia_pd_entries; ++i) {
302 uint32_t iaid = e[i].iaid;
303
304 // check if this is an unprocessed IAID and skip if not.
305 int new_iaid = 1;
306 for (int j = i-1; j >= 0; j--) {
307 if (e[j].iaid == iaid) {
308 new_iaid = 0;
309 break;
310 }
311 }
312
313 if (!new_iaid)
314 continue;
315
316 // construct header
317 struct dhcpv6_ia_hdr hdr_ia_pd = {
318 htons(DHCPV6_OPT_IA_PD),
319 htons(sizeof(hdr_ia_pd) - 4),
320 iaid, 0, 0
321 };
322
323 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
324 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
325 ia_pd_len += sizeof(hdr_ia_pd);
326
327 for (size_t j = i; j < ia_pd_entries; j++) {
328 if (e[j].iaid != iaid)
329 continue;
330
331 uint8_t ex_len = 0;
332 if (e[j].priority > 0)
333 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
334
335 struct dhcpv6_ia_prefix p = {
336 .type = htons(DHCPV6_OPT_IA_PREFIX),
337 .len = htons(sizeof(p) - 4U + ex_len),
338 .prefix = e[j].length,
339 .addr = e[j].target
340 };
341
342 if (type == DHCPV6_MSG_REQUEST) {
343 p.preferred = htonl(e[j].preferred);
344 p.valid = htonl(e[j].valid);
345 }
346
347 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
348 ia_pd_len += sizeof(p);
349
350 if (ex_len) {
351 ia_pd[ia_pd_len++] = 0;
352 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
353 ia_pd[ia_pd_len++] = 0;
354 ia_pd[ia_pd_len++] = ex_len - 4;
355 ia_pd[ia_pd_len++] = e[j].priority;
356
357 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
358 excl >>= (64 - e[j].priority);
359 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
360
361 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
362 ia_pd[ia_pd_len + i] = excl & 0xff;
363 ia_pd_len += ex_len - 5;
364 }
365
366 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
367 }
368 }
369 }
370
371 if (ia_pd_entries > 0)
372 request_prefix = 1;
373
374 // Build IA_NAs
375 size_t ia_na_entries, ia_na_len = 0;
376 void *ia_na = NULL;
377 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
378 ia_na_entries /= sizeof(*e);
379
380 struct dhcpv6_ia_hdr hdr_ia_na = {
381 htons(DHCPV6_OPT_IA_NA),
382 htons(sizeof(hdr_ia_na) - 4),
383 htonl(1), 0, 0
384 };
385
386 struct dhcpv6_ia_addr pa[ia_na_entries];
387 for (size_t i = 0; i < ia_na_entries; ++i) {
388 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
389 pa[i].len = htons(sizeof(pa[i]) - 4U);
390 pa[i].addr = e[i].target;
391
392 if (type == DHCPV6_MSG_REQUEST) {
393 pa[i].preferred = htonl(e[i].preferred);
394 pa[i].valid = htonl(e[i].valid);
395 } else {
396 pa[i].preferred = 0;
397 pa[i].valid = 0;
398 }
399 }
400
401 ia_na = pa;
402 ia_na_len = sizeof(pa);
403 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
404
405 // Reconfigure Accept
406 struct {
407 uint16_t type;
408 uint16_t length;
409 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
410
411 // Request Information Refresh
412 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
413
414 // Build vendor-class option
415 size_t vendor_class_len, user_class_len;
416 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
417 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
418
419 struct {
420 uint16_t type;
421 uint16_t length;
422 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
423
424 struct {
425 uint16_t type;
426 uint16_t length;
427 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
428
429 // Prepare Header
430 size_t oro_len;
431 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
432 struct {
433 uint8_t type;
434 uint8_t trid[3];
435 uint16_t elapsed_type;
436 uint16_t elapsed_len;
437 uint16_t elapsed_value;
438 uint16_t oro_type;
439 uint16_t oro_len;
440 } hdr = {
441 type, {trid[0], trid[1], trid[2]},
442 htons(DHCPV6_OPT_ELAPSED), htons(2),
443 htons((ecs > 0xffff) ? 0xffff : ecs),
444 htons(DHCPV6_OPT_ORO), htons(oro_len),
445 };
446
447 struct iovec iov[IOV_TOTAL] = {
448 [IOV_HDR] = {&hdr, sizeof(hdr)},
449 [IOV_ORO] = {oro, oro_len},
450 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
451 [IOV_CL_ID] = {cl_id, cl_id_len},
452 [IOV_SRV_ID] = {srv_id, srv_id_len},
453 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
454 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
455 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
456 [IOV_USER_CLASS] = {user_class, user_class_len},
457 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
458 [IOV_FQDN] = {&fqdn, fqdn_len},
459 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
460 [IOV_IA_NA] = {ia_na, ia_na_len},
461 [IOV_IA_PD] = {ia_pd, ia_pd_len},
462 };
463
464 size_t cnt = IOV_TOTAL;
465 if (type == DHCPV6_MSG_INFO_REQ) {
466 cnt = 9;
467 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
468 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
469 } else if (!request_prefix) {
470 cnt = 13;
471 }
472
473 // Disable IAs if not used
474 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
475 iov[IOV_HDR_IA_NA].iov_len = 0;
476
477 if (na_mode == IA_MODE_NONE)
478 iov[IOV_HDR_IA_NA].iov_len = 0;
479
480 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
481 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
482 iov[IOV_RECONF_ACCEPT].iov_len = 0;
483
484 if (!(client_options & DHCPV6_CLIENT_FQDN))
485 iov[IOV_FQDN].iov_len = 0;
486
487 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
488 0, ALL_DHCPV6_RELAYS, ifindex};
489 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
490 .msg_iov = iov, .msg_iovlen = cnt};
491
492 sendmsg(sock, &msg, 0);
493 }
494
495
496 static int64_t dhcpv6_rand_delay(int64_t time)
497 {
498 int random;
499 odhcp6c_random(&random, sizeof(random));
500 return (time * ((int64_t)random % 1000LL)) / 10000LL;
501 }
502
503
504 int dhcpv6_request(enum dhcpv6_msg type)
505 {
506 uint8_t rc = 0;
507 uint64_t timeout = UINT32_MAX;
508 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
509
510 if (retx->delay) {
511 struct timespec ts = {0, 0};
512 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
513 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
514 }
515
516 if (type == DHCPV6_MSG_UNKNOWN)
517 timeout = t1;
518 else if (type == DHCPV6_MSG_RENEW)
519 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
520 else if (type == DHCPV6_MSG_REBIND)
521 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
522
523 if (timeout == 0)
524 return -1;
525
526 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
527 retx->name, (unsigned long long)timeout, retx->max_rc);
528
529 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
530
531 // Generate transaction ID
532 uint8_t trid[3] = {0, 0, 0};
533 if (type != DHCPV6_MSG_UNKNOWN)
534 odhcp6c_random(trid, sizeof(trid));
535 ssize_t len = -1;
536 int64_t rto = 0;
537
538 do {
539 if (rto == 0) {
540 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
541
542 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
543 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
544 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
545
546 rto = (retx->init_timeo * 1000 + delay);
547 }
548 else
549 rto = (2 * rto + dhcpv6_rand_delay(rto));
550
551 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
552 rto = retx->max_timeo * 1000 +
553 dhcpv6_rand_delay(retx->max_timeo * 1000);
554
555 // Calculate end for this round and elapsed time
556 uint64_t round_end = round_start + rto;
557 elapsed = round_start - start;
558
559 // Don't wait too long if timeout differs from infinite
560 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
561 round_end = timeout * 1000 + start;
562
563 // Built and send package
564 switch (type) {
565 case DHCPV6_MSG_UNKNOWN:
566 break;
567 default:
568 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
569 retx->name, (unsigned long long)elapsed, rc);
570 // Fall through
571 case DHCPV6_MSG_SOLICIT:
572 case DHCPV6_MSG_INFO_REQ:
573 dhcpv6_send(type, trid, elapsed / 10);
574 rc++;
575 }
576
577 // Receive rounds
578 for (; len < 0 && (round_start < round_end);
579 round_start = odhcp6c_get_milli_time()) {
580 uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
581 struct iovec iov = {buf, sizeof(buf)};
582 struct sockaddr_in6 addr;
583 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
584 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
585 .msg_controllen = sizeof(cmsg_buf)};
586 struct in6_pktinfo *pktinfo = NULL;
587
588
589 // Check for pending signal
590 if (odhcp6c_signal_process())
591 return -1;
592
593 // Set timeout for receiving
594 uint64_t t = round_end - round_start;
595 struct timeval tv = {t / 1000, (t % 1000) * 1000};
596 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
597 &tv, sizeof(tv));
598
599 // Receive cycle
600 len = recvmsg(sock, &msg, 0);
601 if (len < 0)
602 continue;
603
604 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
605 ch = CMSG_NXTHDR(&msg, ch)) {
606 if (ch->cmsg_level == SOL_IPV6 &&
607 ch->cmsg_type == IPV6_PKTINFO) {
608 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
609 break;
610 }
611 }
612
613 if (pktinfo == NULL) {
614 len = -1;
615 continue;
616 }
617
618 if (!dhcpv6_response_is_valid(buf, len, trid,
619 type, &pktinfo->ipi6_addr)) {
620 len = -1;
621 continue;
622 }
623
624 uint8_t *opt = &buf[4];
625 uint8_t *opt_end = opt + len - 4;
626
627 round_start = odhcp6c_get_milli_time();
628 elapsed = round_start - start;
629 syslog(LOG_NOTICE, "Got a valid reply after "
630 "%llums", (unsigned long long)elapsed);
631
632 if (retx->handler_reply)
633 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
634
635 if (len > 0 && round_end - round_start > 1000)
636 round_end = 1000 + round_start;
637 }
638
639 // Allow
640 if (retx->handler_finish)
641 len = retx->handler_finish();
642 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
643 (!retx->max_rc || rc < retx->max_rc));
644 return len;
645 }
646
647 // Message validation checks according to RFC3315 chapter 15
648 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
649 const uint8_t transaction[3], enum dhcpv6_msg type,
650 const struct in6_addr *daddr)
651 {
652 const struct dhcpv6_header *rep = buf;
653 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
654 transaction, sizeof(rep->tr_id)))
655 return false; // Invalid reply
656
657 if (type == DHCPV6_MSG_SOLICIT) {
658 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
659 rep->msg_type != DHCPV6_MSG_REPLY)
660 return false;
661 } else if (type == DHCPV6_MSG_UNKNOWN) {
662 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
663 return false;
664 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
665 return false;
666 }
667
668 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
669 rcmsg = DHCPV6_MSG_UNKNOWN;
670 uint16_t otype, olen = UINT16_MAX;
671 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
672 ia_present = false, options_valid = true;
673
674 size_t client_id_len, server_id_len;
675 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
676 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
677
678 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
679 if (otype == DHCPV6_OPT_CLIENTID) {
680 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
681 &odata[-4], client_id, client_id_len);
682 } else if (otype == DHCPV6_OPT_SERVERID) {
683 if (server_id_len)
684 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
685 &odata[-4], server_id, server_id_len);
686 else
687 serverid_ok = true;
688 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
689 sizeof(struct dhcpv6_auth_reconfigure)) {
690 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
691 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
692 continue;
693
694 md5_ctx_t md5;
695 uint8_t serverhash[16], secretbytes[64], hash[16];
696 memcpy(serverhash, r->key, sizeof(serverhash));
697 memset(r->key, 0, sizeof(r->key));
698
699 memset(secretbytes, 0, sizeof(secretbytes));
700 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
701
702 for (size_t i = 0; i < sizeof(secretbytes); ++i)
703 secretbytes[i] ^= 0x36;
704
705 md5_begin(&md5);
706 md5_hash(secretbytes, sizeof(secretbytes), &md5);
707 md5_hash(buf, len, &md5);
708 md5_end(hash, &md5);
709
710 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
711 secretbytes[i] ^= 0x36;
712 secretbytes[i] ^= 0x5c;
713 }
714
715 md5_begin(&md5);
716 md5_hash(secretbytes, sizeof(secretbytes), &md5);
717 md5_hash(hash, 16, &md5);
718 md5_end(hash, &md5);
719
720 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
721 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
722 rcmsg = odata[0];
723 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
724 ia_present = true;
725 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
726 options_valid = false;
727 }
728 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
729 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
730 // Options are not allowed on global level
731 options_valid = false;
732 }
733 }
734
735 if (!options_valid || ((odata + olen) > end))
736 return false;
737
738 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
739 return false;
740
741 if (rep->msg_type == DHCPV6_MSG_RECONF) {
742 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
743 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
744 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
745 return false;
746 }
747
748 return clientid_ok && serverid_ok;
749 }
750
751
752 int dhcpv6_poll_reconfigure(void)
753 {
754 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
755 if (ret != -1)
756 ret = dhcpv6_request(ret);
757
758 return ret;
759 }
760
761
762 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
763 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
764 {
765 uint16_t otype, olen;
766 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
767 dhcpv6_for_each_option(opt, end, otype, olen, odata)
768 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
769 odata[0] == DHCPV6_MSG_RENEW ||
770 odata[0] == DHCPV6_MSG_INFO_REQ))
771 msg = odata[0];
772
773 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
774 return msg;
775 }
776
777
778 // Collect all advertised servers
779 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
780 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
781 {
782 uint16_t olen, otype;
783 uint8_t *odata, pref = 0;
784 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
785 DHCPV6_SOL_MAX_RT,
786 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
787 bool have_na = false;
788 int have_pd = 0;
789
790 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
791 if (orig == DHCPV6_MSG_SOLICIT &&
792 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
793 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
794 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
795 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
796 }
797
798 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
799 memcpy(cand.duid, odata, olen);
800 cand.duid_len = olen;
801 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
802 cand.preference >= 0) {
803 cand.preference = pref = odata[0];
804 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
805 cand.wants_reconfigure = true;
806 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
807 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
808 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
809 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
810 cand.sol_max_rt = sol_max_rt;
811 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
812 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
813 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
814 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
815 cand.inf_max_rt = inf_max_rt;
816 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
817 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
818 uint8_t *oend = odata + olen, *d;
819 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
820 if (otype == DHCPV6_OPT_IA_PREFIX &&
821 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
822 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
823 have_pd = p->prefix;
824 }
825 }
826 } else if (otype == DHCPV6_OPT_IA_NA) {
827 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
828 uint8_t *oend = odata + olen, *d;
829 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
830 if (otype == DHCPV6_OPT_IA_ADDR &&
831 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
832 have_na = true;
833 }
834 }
835
836 if ((!have_na && na_mode == IA_MODE_FORCE) ||
837 (!have_pd && pd_mode == IA_MODE_FORCE)) {
838 /*
839 * RFC7083 states to process the SOL_MAX_RT and
840 * INF_MAX_RT options even if the DHCPv6 server
841 * did not propose any IA_NA and/or IA_PD
842 */
843 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
844 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
845 return -1;
846 }
847
848 if (na_mode != IA_MODE_NONE && !have_na) {
849 cand.has_noaddravail = true;
850 cand.preference -= 1000;
851 }
852
853 if (pd_mode != IA_MODE_NONE) {
854 if (have_pd)
855 cand.preference += 2000 + (128 - have_pd);
856 else
857 cand.preference -= 2000;
858 }
859
860 if (cand.duid_len > 0) {
861 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
862 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
863 dhcpv6_add_server_cand(&cand);
864 }
865
866 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
867 }
868
869
870 static int dhcpv6_commit_advert(void)
871 {
872 return dhcpv6_promote_server_cand();
873 }
874
875
876 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
877 const void *opt, const void *end, const struct sockaddr_in6 *from)
878 {
879 dhcpv6_handle_advert(orig, rc, opt, end, from);
880 if (dhcpv6_commit_advert() < 0)
881 return -1;
882
883 return dhcpv6_handle_reply(orig, rc, opt, end, from);
884 }
885
886
887 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
888 const void *opt, const void *end, const struct sockaddr_in6 *from)
889 {
890 uint8_t *odata;
891 uint16_t otype, olen;
892 uint32_t refresh = 86400;
893 int ret = 1;
894 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
895
896 odhcp6c_expire();
897
898 if (orig == DHCPV6_MSG_UNKNOWN) {
899 static time_t last_update = 0;
900 time_t now = odhcp6c_get_milli_time() / 1000;
901
902 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
903 last_update = now;
904
905 if (t1 != UINT32_MAX)
906 t1 -= elapsed;
907
908 if (t2 != UINT32_MAX)
909 t2 -= elapsed;
910
911 if (t3 != UINT32_MAX)
912 t3 -= elapsed;
913
914 if (t1 < 0)
915 t1 = 0;
916
917 if (t2 < 0)
918 t2 = 0;
919
920 if (t3 < 0)
921 t3 = 0;
922 }
923
924 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
925 // Delete NA and PD we have in the state from the Advert
926 odhcp6c_clear_state(STATE_IA_NA);
927 odhcp6c_clear_state(STATE_IA_PD);
928 }
929
930 if (opt) {
931 odhcp6c_clear_state(STATE_DNS);
932 odhcp6c_clear_state(STATE_SEARCH);
933 odhcp6c_clear_state(STATE_SNTP_IP);
934 odhcp6c_clear_state(STATE_NTP_IP);
935 odhcp6c_clear_state(STATE_NTP_FQDN);
936 odhcp6c_clear_state(STATE_SIP_IP);
937 odhcp6c_clear_state(STATE_SIP_FQDN);
938 odhcp6c_clear_state(STATE_AFTR_NAME);
939 odhcp6c_clear_state(STATE_CER);
940 odhcp6c_clear_state(STATE_S46_MAPT);
941 odhcp6c_clear_state(STATE_S46_MAPE);
942 odhcp6c_clear_state(STATE_S46_LW);
943 odhcp6c_clear_state(STATE_PASSTHRU);
944 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
945
946 // Parse and find all matching IAs
947 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
948 bool passthru = true;
949
950 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
951 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
952 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
953
954 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
955 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
956 continue;
957
958 // Test ID
959 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
960 continue;
961
962 uint16_t code = DHCPV6_Success;
963 uint16_t stype, slen;
964 uint8_t *sdata;
965 // Get and handle status code
966 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
967 stype, slen, sdata) {
968 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
969 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
970 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
971
972 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
973
974 if (code == DHCPV6_Success)
975 continue;
976
977 dhcpv6_handle_ia_status_code(orig, ia_hdr,
978 code, mdata, mlen, handled_status_codes, &ret);
979
980
981 if (ret > 0)
982 return ret;
983 break;
984 }
985 }
986
987 if (code != DHCPV6_Success)
988 continue;
989
990 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
991 passthru = false;
992 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
993 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
994 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
995 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
996
997 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
998 passthru = false;
999 }
1000 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1001 if (olen % 16 == 0)
1002 odhcp6c_add_state(STATE_DNS, odata, olen);
1003 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1004 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1005 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1006 if (olen % 16 == 0)
1007 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1008 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1009 uint16_t stype, slen;
1010 uint8_t *sdata;
1011 // Test status and bail if error
1012 dhcpv6_for_each_option(odata, odata + olen,
1013 stype, slen, sdata) {
1014 if (slen == 16 && (stype == NTP_MC_ADDR ||
1015 stype == NTP_SRV_ADDR))
1016 odhcp6c_add_state(STATE_NTP_IP,
1017 sdata, slen);
1018 else if (slen > 0 && stype == NTP_SRV_FQDN)
1019 odhcp6c_add_state(STATE_NTP_FQDN,
1020 sdata, slen);
1021 }
1022 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1023 if (olen == 16)
1024 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1025 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1026 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1027 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1028 refresh = ntohl(*((uint32_t*)odata));
1029 passthru = false;
1030 } else if (otype == DHCPV6_OPT_AUTH) {
1031 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1032 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1033 if (r->protocol == 3 && r->algorithm == 1 &&
1034 r->reconf_type == 1)
1035 memcpy(reconf_key, r->key, sizeof(r->key));
1036 }
1037 passthru = false;
1038 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1039 size_t cur_len;
1040 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1041 if (cur_len == 0)
1042 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1043 passthru = false;
1044 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1045 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1046 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1047 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1048 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1049 passthru = false;
1050 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1051 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1052 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1053 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1054 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1055 passthru = false;
1056 #ifdef EXT_CER_ID
1057 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1058 sizeof(struct dhcpv6_cer_id)) {
1059 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1060 struct in6_addr any = IN6ADDR_ANY_INIT;
1061 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1062 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1063 passthru = false;
1064 #endif
1065 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1066 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1067 passthru = false;
1068 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1069 size_t mape_len;
1070 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1071 if (mape_len == 0)
1072 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1073 passthru = false;
1074 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1075 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1076 passthru = false;
1077 } else if (otype == DHCPV6_OPT_CLIENTID ||
1078 otype == DHCPV6_OPT_SERVERID ||
1079 otype == DHCPV6_OPT_IA_TA ||
1080 otype == DHCPV6_OPT_PREF ||
1081 otype == DHCPV6_OPT_UNICAST ||
1082 otype == DHCPV6_OPT_FQDN ||
1083 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1084 passthru = false;
1085 } else {
1086 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1087 }
1088
1089 if (passthru)
1090 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1091 }
1092 }
1093
1094 if (orig != DHCPV6_MSG_INFO_REQ) {
1095 // Update refresh timers if no fatal status code was received
1096 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1097 switch (orig) {
1098 case DHCPV6_MSG_RENEW:
1099 // Send further renews if T1 is not set
1100 if (!t1)
1101 ret = -1;
1102 break;
1103 case DHCPV6_MSG_REBIND:
1104 // Send further rebinds if T1 and T2 is not set
1105 if (!t1 && !t2)
1106 ret = -1;
1107 break;
1108
1109 case DHCPV6_MSG_REQUEST:
1110 // All server candidates can be cleared if not yet bound
1111 if (!odhcp6c_is_bound())
1112 dhcpv6_clear_all_server_cand();
1113
1114 default :
1115 break;
1116 }
1117
1118 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1119 odhcp6c_clear_state(STATE_SERVER_ADDR);
1120 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1121 }
1122 }
1123 }
1124 else if (ret > 0) {
1125 // All server candidates can be cleared if not yet bound
1126 if (!odhcp6c_is_bound())
1127 dhcpv6_clear_all_server_cand();
1128
1129 t1 = refresh;
1130 }
1131
1132 return ret;
1133 }
1134
1135
1136 static int dhcpv6_parse_ia(void *opt, void *end)
1137 {
1138 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1139 int parsed_ia = 0;
1140 uint32_t t1, t2;
1141 uint16_t otype, olen;
1142 uint8_t *odata;
1143
1144 t1 = ntohl(ia_hdr->t1);
1145 t2 = ntohl(ia_hdr->t2);
1146
1147 if (t1 > t2)
1148 return 0;
1149
1150 // Update address IA
1151 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1152 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1153 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1154
1155 entry.iaid = ia_hdr->iaid;
1156
1157 if (otype == DHCPV6_OPT_IA_PREFIX) {
1158 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1159 if (olen + 4U < sizeof(*prefix))
1160 continue;
1161
1162 entry.valid = ntohl(prefix->valid);
1163 entry.preferred = ntohl(prefix->preferred);
1164
1165 if (entry.preferred > entry.valid)
1166 continue;
1167
1168 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1169 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1170 if (entry.t1 > entry.t2)
1171 entry.t1 = entry.t2;
1172
1173 entry.length = prefix->prefix;
1174 entry.target = prefix->addr;
1175 uint16_t stype, slen;
1176 uint8_t *sdata;
1177
1178 // Parse PD-exclude
1179 bool ok = true;
1180 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1181 odata + olen, stype, slen, sdata) {
1182 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1183 continue;
1184
1185 uint8_t elen = sdata[0];
1186 if (elen > 64)
1187 elen = 64;
1188
1189 if (entry.length < 32 || elen <= entry.length) {
1190 ok = false;
1191 continue;
1192 }
1193
1194
1195 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1196 if (slen <= bytes) {
1197 ok = false;
1198 continue;
1199 }
1200
1201 uint32_t exclude = 0;
1202 do {
1203 exclude = exclude << 8 | sdata[bytes];
1204 } while (--bytes);
1205
1206 exclude >>= 8 - ((elen - entry.length) % 8);
1207 exclude <<= 64 - elen;
1208
1209 // Abusing router & priority fields for exclusion
1210 entry.router = entry.target;
1211 entry.router.s6_addr32[1] |= htonl(exclude);
1212 entry.priority = elen;
1213 }
1214
1215 if (ok) {
1216 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1217 parsed_ia++;
1218 }
1219
1220 entry.priority = 0;
1221 memset(&entry.router, 0, sizeof(entry.router));
1222 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1223 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1224 if (olen + 4U < sizeof(*addr))
1225 continue;
1226
1227 entry.preferred = ntohl(addr->preferred);
1228 entry.valid = ntohl(addr->valid);
1229
1230 if (entry.preferred > entry.valid)
1231 continue;
1232
1233 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1234 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1235 if (entry.t1 > entry.t2)
1236 entry.t1 = entry.t2;
1237
1238 entry.length = 128;
1239 entry.target = addr->addr;
1240
1241 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1242 parsed_ia++;
1243 }
1244 }
1245 return parsed_ia;
1246 }
1247
1248
1249 static int dhcpv6_calc_refresh_timers(void)
1250 {
1251 struct odhcp6c_entry *e;
1252 size_t ia_na_entries, ia_pd_entries, i;
1253 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1254
1255 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1256 ia_na_entries /= sizeof(*e);
1257 for (i = 0; i < ia_na_entries; i++) {
1258 if (e[i].t1 < l_t1)
1259 l_t1 = e[i].t1;
1260
1261 if (e[i].t2 < l_t2)
1262 l_t2 = e[i].t2;
1263
1264 if (e[i].valid > l_t3)
1265 l_t3 = e[i].valid;
1266 }
1267
1268 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1269 ia_pd_entries /= sizeof(*e);
1270 for (i = 0; i < ia_pd_entries; i++) {
1271 if (e[i].t1 < l_t1)
1272 l_t1 = e[i].t1;
1273
1274 if (e[i].t2 < l_t2)
1275 l_t2 = e[i].t2;
1276
1277 if (e[i].valid > l_t3)
1278 l_t3 = e[i].valid;
1279 }
1280
1281 if (ia_pd_entries || ia_na_entries) {
1282 t1 = l_t1;
1283 t2 = l_t2;
1284 t3 = l_t3;
1285 } else {
1286 t1 = 600;
1287 }
1288
1289 return (int)(ia_pd_entries + ia_na_entries);
1290 }
1291
1292
1293 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1294 const void *status_msg, int len)
1295 {
1296 const char *src = status_msg;
1297 char buf[len + 3];
1298 char *dst = buf;
1299
1300 if (len) {
1301 *dst++ = '(';
1302 while (len--) {
1303 *dst = isprint((unsigned char)*src) ? *src : '?';
1304 src++;
1305 dst++;
1306 }
1307 *dst++ = ')';
1308 }
1309 *dst = 0;
1310
1311 syslog(LOG_WARNING, "Server returned %s status %i %s",
1312 scope, code, buf);
1313 }
1314
1315
1316 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1317 const uint16_t code, const void *status_msg, const int len,
1318 int *ret)
1319 {
1320 dhcpv6_log_status_code(code, "message", status_msg, len);
1321
1322 switch (code) {
1323 case DHCPV6_UnspecFail:
1324 // Generic failure
1325 *ret = 0;
1326 break;
1327
1328 case DHCPV6_UseMulticast:
1329 // TODO handle multicast status code
1330 break;
1331
1332 case DHCPV6_NoAddrsAvail:
1333 case DHCPV6_NoPrefixAvail:
1334 if (orig == DHCPV6_MSG_REQUEST)
1335 *ret = 0; // Failure
1336 break;
1337
1338 default:
1339 break;
1340 }
1341 }
1342
1343
1344 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1345 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1346 const void *status_msg, const int len,
1347 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1348 {
1349 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1350 "IA_NA" : "IA_PD", status_msg, len);
1351
1352 switch (code) {
1353 case DHCPV6_NoBinding:
1354 switch (orig) {
1355 case DHCPV6_MSG_RENEW:
1356 case DHCPV6_MSG_REBIND:
1357 if ((*ret > 0) && !handled_status_codes[code])
1358 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1359 break;
1360
1361 default:
1362 break;
1363 }
1364 break;
1365
1366 default:
1367 *ret = 0;
1368 break;
1369 }
1370 }
1371
1372 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1373 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1374 {
1375 size_t cand_len, i;
1376 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1377
1378 // Remove identical duid server candidate
1379 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1380 if (cand->duid_len == c[i].duid_len &&
1381 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1382 free(c[i].ia_na);
1383 free(c[i].ia_pd);
1384 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1385 break;
1386 }
1387 }
1388
1389 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1390 i < cand_len / sizeof(*c); ++i) {
1391 if (c[i].preference < cand->preference)
1392 break;
1393 }
1394
1395 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1396 free(cand->ia_na);
1397 free(cand->ia_pd);
1398 }
1399 }
1400
1401 static void dhcpv6_clear_all_server_cand(void)
1402 {
1403 size_t cand_len, i;
1404 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1405
1406 // Server candidates need deep delete for IA_NA/IA_PD
1407 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1408 free(c[i].ia_na);
1409 free(c[i].ia_pd);
1410 }
1411 odhcp6c_clear_state(STATE_SERVER_CAND);
1412 }
1413
1414 int dhcpv6_promote_server_cand(void)
1415 {
1416 size_t cand_len;
1417 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1418 uint16_t hdr[2];
1419 int ret = DHCPV6_STATELESS;
1420
1421 // Clear lingering candidate state info
1422 odhcp6c_clear_state(STATE_SERVER_ID);
1423 odhcp6c_clear_state(STATE_IA_NA);
1424 odhcp6c_clear_state(STATE_IA_PD);
1425
1426 if (!cand_len)
1427 return -1;
1428
1429 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1430 na_mode = IA_MODE_NONE;
1431
1432 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1433 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1434
1435 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1436 }
1437
1438 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1439 hdr[1] = htons(cand->duid_len);
1440 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1441 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1442 accept_reconfig = cand->wants_reconfigure;
1443 if (cand->ia_na_len) {
1444 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1445 free(cand->ia_na);
1446 if (na_mode != IA_MODE_NONE)
1447 ret = DHCPV6_STATEFUL;
1448 }
1449 if (cand->ia_pd_len) {
1450 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1451 free(cand->ia_pd);
1452 if (request_prefix)
1453 ret = DHCPV6_STATEFUL;
1454 }
1455
1456 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1457 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1458
1459 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1460
1461 return ret;
1462 }
Openwrt DHCPv6 Client