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[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];
581 uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]
582 __aligned(__alignof__(struct cmsghdr));
583 struct iovec iov = {buf, sizeof(buf)};
584 struct sockaddr_in6 addr;
585 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
586 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
587 .msg_controllen = sizeof(cmsg_buf)};
588 struct in6_pktinfo *pktinfo = NULL;
589
590
591 // Check for pending signal
592 if (odhcp6c_signal_process())
593 return -1;
594
595 // Set timeout for receiving
596 uint64_t t = round_end - round_start;
597 struct timeval tv = {t / 1000, (t % 1000) * 1000};
598 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
599 &tv, sizeof(tv));
600
601 // Receive cycle
602 len = recvmsg(sock, &msg, 0);
603 if (len < 0)
604 continue;
605
606 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
607 ch = CMSG_NXTHDR(&msg, ch)) {
608 if (ch->cmsg_level == SOL_IPV6 &&
609 ch->cmsg_type == IPV6_PKTINFO) {
610 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
611 break;
612 }
613 }
614
615 if (pktinfo == NULL) {
616 len = -1;
617 continue;
618 }
619
620 if (!dhcpv6_response_is_valid(buf, len, trid,
621 type, &pktinfo->ipi6_addr)) {
622 len = -1;
623 continue;
624 }
625
626 uint8_t *opt = &buf[4];
627 uint8_t *opt_end = opt + len - 4;
628
629 round_start = odhcp6c_get_milli_time();
630 elapsed = round_start - start;
631 syslog(LOG_NOTICE, "Got a valid reply after "
632 "%llums", (unsigned long long)elapsed);
633
634 if (retx->handler_reply)
635 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
636
637 if (len > 0 && round_end - round_start > 1000)
638 round_end = 1000 + round_start;
639 }
640
641 // Allow
642 if (retx->handler_finish)
643 len = retx->handler_finish();
644 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
645 (!retx->max_rc || rc < retx->max_rc));
646 return len;
647 }
648
649 // Message validation checks according to RFC3315 chapter 15
650 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
651 const uint8_t transaction[3], enum dhcpv6_msg type,
652 const struct in6_addr *daddr)
653 {
654 const struct dhcpv6_header *rep = buf;
655 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
656 transaction, sizeof(rep->tr_id)))
657 return false; // Invalid reply
658
659 if (type == DHCPV6_MSG_SOLICIT) {
660 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
661 rep->msg_type != DHCPV6_MSG_REPLY)
662 return false;
663 } else if (type == DHCPV6_MSG_UNKNOWN) {
664 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
665 return false;
666 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
667 return false;
668 }
669
670 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
671 rcmsg = DHCPV6_MSG_UNKNOWN;
672 uint16_t otype, olen = UINT16_MAX;
673 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
674 ia_present = false, options_valid = true;
675
676 size_t client_id_len, server_id_len;
677 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
678 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
679
680 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
681 if (otype == DHCPV6_OPT_CLIENTID) {
682 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
683 &odata[-4], client_id, client_id_len);
684 } else if (otype == DHCPV6_OPT_SERVERID) {
685 if (server_id_len)
686 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
687 &odata[-4], server_id, server_id_len);
688 else
689 serverid_ok = true;
690 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
691 sizeof(struct dhcpv6_auth_reconfigure)) {
692 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
693 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
694 continue;
695
696 md5_ctx_t md5;
697 uint8_t serverhash[16], secretbytes[64], hash[16];
698 memcpy(serverhash, r->key, sizeof(serverhash));
699 memset(r->key, 0, sizeof(r->key));
700
701 memset(secretbytes, 0, sizeof(secretbytes));
702 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
703
704 for (size_t i = 0; i < sizeof(secretbytes); ++i)
705 secretbytes[i] ^= 0x36;
706
707 md5_begin(&md5);
708 md5_hash(secretbytes, sizeof(secretbytes), &md5);
709 md5_hash(buf, len, &md5);
710 md5_end(hash, &md5);
711
712 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
713 secretbytes[i] ^= 0x36;
714 secretbytes[i] ^= 0x5c;
715 }
716
717 md5_begin(&md5);
718 md5_hash(secretbytes, sizeof(secretbytes), &md5);
719 md5_hash(hash, 16, &md5);
720 md5_end(hash, &md5);
721
722 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
723 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
724 rcmsg = odata[0];
725 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
726 ia_present = true;
727 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
728 options_valid = false;
729 }
730 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
731 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
732 // Options are not allowed on global level
733 options_valid = false;
734 }
735 }
736
737 if (!options_valid || ((odata + olen) > end))
738 return false;
739
740 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
741 return false;
742
743 if (rep->msg_type == DHCPV6_MSG_RECONF) {
744 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
745 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
746 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
747 return false;
748 }
749
750 return clientid_ok && serverid_ok;
751 }
752
753
754 int dhcpv6_poll_reconfigure(void)
755 {
756 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
757 if (ret != -1)
758 ret = dhcpv6_request(ret);
759
760 return ret;
761 }
762
763
764 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
765 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
766 {
767 uint16_t otype, olen;
768 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
769 dhcpv6_for_each_option(opt, end, otype, olen, odata)
770 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
771 odata[0] == DHCPV6_MSG_RENEW ||
772 odata[0] == DHCPV6_MSG_INFO_REQ))
773 msg = odata[0];
774
775 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
776 return msg;
777 }
778
779
780 // Collect all advertised servers
781 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
782 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
783 {
784 uint16_t olen, otype;
785 uint8_t *odata, pref = 0;
786 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
787 DHCPV6_SOL_MAX_RT,
788 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
789 bool have_na = false;
790 int have_pd = 0;
791
792 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
793 if (orig == DHCPV6_MSG_SOLICIT &&
794 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
795 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
796 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
797 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
798 }
799
800 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
801 memcpy(cand.duid, odata, olen);
802 cand.duid_len = olen;
803 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
804 cand.preference >= 0) {
805 cand.preference = pref = odata[0];
806 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
807 cand.wants_reconfigure = true;
808 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
809 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
810 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
811 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
812 cand.sol_max_rt = sol_max_rt;
813 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
814 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
815 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
816 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
817 cand.inf_max_rt = inf_max_rt;
818 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
819 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
820 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
821 uint8_t *oend = odata + olen, *d;
822 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
823 if (otype == DHCPV6_OPT_IA_PREFIX &&
824 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
825 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
826 have_pd = p->prefix;
827 }
828 }
829 } else if (otype == DHCPV6_OPT_IA_NA &&
830 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
831 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
832 uint8_t *oend = odata + olen, *d;
833 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
834 if (otype == DHCPV6_OPT_IA_ADDR &&
835 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
836 have_na = true;
837 }
838 }
839
840 if ((!have_na && na_mode == IA_MODE_FORCE) ||
841 (!have_pd && pd_mode == IA_MODE_FORCE)) {
842 /*
843 * RFC7083 states to process the SOL_MAX_RT and
844 * INF_MAX_RT options even if the DHCPv6 server
845 * did not propose any IA_NA and/or IA_PD
846 */
847 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
848 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
849 return -1;
850 }
851
852 if (na_mode != IA_MODE_NONE && !have_na) {
853 cand.has_noaddravail = true;
854 cand.preference -= 1000;
855 }
856
857 if (pd_mode != IA_MODE_NONE) {
858 if (have_pd)
859 cand.preference += 2000 + (128 - have_pd);
860 else
861 cand.preference -= 2000;
862 }
863
864 if (cand.duid_len > 0) {
865 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
866 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
867 dhcpv6_add_server_cand(&cand);
868 }
869
870 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
871 }
872
873
874 static int dhcpv6_commit_advert(void)
875 {
876 return dhcpv6_promote_server_cand();
877 }
878
879
880 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
881 const void *opt, const void *end, const struct sockaddr_in6 *from)
882 {
883 dhcpv6_handle_advert(orig, rc, opt, end, from);
884 if (dhcpv6_commit_advert() < 0)
885 return -1;
886
887 return dhcpv6_handle_reply(orig, rc, opt, end, from);
888 }
889
890
891 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
892 const void *opt, const void *end, const struct sockaddr_in6 *from)
893 {
894 uint8_t *odata;
895 uint16_t otype, olen;
896 uint32_t refresh = 86400;
897 int ret = 1;
898 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
899
900 odhcp6c_expire();
901
902 if (orig == DHCPV6_MSG_UNKNOWN) {
903 static time_t last_update = 0;
904 time_t now = odhcp6c_get_milli_time() / 1000;
905
906 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
907 last_update = now;
908
909 if (t1 != UINT32_MAX)
910 t1 -= elapsed;
911
912 if (t2 != UINT32_MAX)
913 t2 -= elapsed;
914
915 if (t3 != UINT32_MAX)
916 t3 -= elapsed;
917
918 if (t1 < 0)
919 t1 = 0;
920
921 if (t2 < 0)
922 t2 = 0;
923
924 if (t3 < 0)
925 t3 = 0;
926 }
927
928 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
929 // Delete NA and PD we have in the state from the Advert
930 odhcp6c_clear_state(STATE_IA_NA);
931 odhcp6c_clear_state(STATE_IA_PD);
932 }
933
934 if (opt) {
935 odhcp6c_clear_state(STATE_DNS);
936 odhcp6c_clear_state(STATE_SEARCH);
937 odhcp6c_clear_state(STATE_SNTP_IP);
938 odhcp6c_clear_state(STATE_NTP_IP);
939 odhcp6c_clear_state(STATE_NTP_FQDN);
940 odhcp6c_clear_state(STATE_SIP_IP);
941 odhcp6c_clear_state(STATE_SIP_FQDN);
942 odhcp6c_clear_state(STATE_AFTR_NAME);
943 odhcp6c_clear_state(STATE_CER);
944 odhcp6c_clear_state(STATE_S46_MAPT);
945 odhcp6c_clear_state(STATE_S46_MAPE);
946 odhcp6c_clear_state(STATE_S46_LW);
947 odhcp6c_clear_state(STATE_PASSTHRU);
948 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
949
950 // Parse and find all matching IAs
951 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
952 bool passthru = true;
953
954 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
955 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
956 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
957
958 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
959 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
960 continue;
961
962 // Test ID
963 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
964 continue;
965
966 uint16_t code = DHCPV6_Success;
967 uint16_t stype, slen;
968 uint8_t *sdata;
969 // Get and handle status code
970 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
971 stype, slen, sdata) {
972 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
973 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
974 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
975
976 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
977
978 if (code == DHCPV6_Success)
979 continue;
980
981 dhcpv6_handle_ia_status_code(orig, ia_hdr,
982 code, mdata, mlen, handled_status_codes, &ret);
983
984
985 if (ret > 0)
986 return ret;
987 break;
988 }
989 }
990
991 if (code != DHCPV6_Success)
992 continue;
993
994 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
995 passthru = false;
996 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
997 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
998 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
999 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1000
1001 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1002 passthru = false;
1003 }
1004 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1005 if (olen % 16 == 0)
1006 odhcp6c_add_state(STATE_DNS, odata, olen);
1007 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1008 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1009 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1010 if (olen % 16 == 0)
1011 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1012 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1013 uint16_t stype, slen;
1014 uint8_t *sdata;
1015 // Test status and bail if error
1016 dhcpv6_for_each_option(odata, odata + olen,
1017 stype, slen, sdata) {
1018 if (slen == 16 && (stype == NTP_MC_ADDR ||
1019 stype == NTP_SRV_ADDR))
1020 odhcp6c_add_state(STATE_NTP_IP,
1021 sdata, slen);
1022 else if (slen > 0 && stype == NTP_SRV_FQDN)
1023 odhcp6c_add_state(STATE_NTP_FQDN,
1024 sdata, slen);
1025 }
1026 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1027 if (olen == 16)
1028 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1029 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1030 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1031 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1032 refresh = ntohl(*((uint32_t*)odata));
1033 passthru = false;
1034 } else if (otype == DHCPV6_OPT_AUTH) {
1035 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1036 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1037 if (r->protocol == 3 && r->algorithm == 1 &&
1038 r->reconf_type == 1)
1039 memcpy(reconf_key, r->key, sizeof(r->key));
1040 }
1041 passthru = false;
1042 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1043 size_t cur_len;
1044 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1045 if (cur_len == 0)
1046 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1047 passthru = false;
1048 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1049 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1050 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1051 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1052 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1053 passthru = false;
1054 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1055 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1056 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1057 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1058 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1059 passthru = false;
1060 #ifdef EXT_CER_ID
1061 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1062 sizeof(struct dhcpv6_cer_id)) {
1063 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1064 struct in6_addr any = IN6ADDR_ANY_INIT;
1065 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1066 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1067 passthru = false;
1068 #endif
1069 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1070 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1071 passthru = false;
1072 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1073 size_t mape_len;
1074 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1075 if (mape_len == 0)
1076 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1077 passthru = false;
1078 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1079 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1080 passthru = false;
1081 } else if (otype == DHCPV6_OPT_CLIENTID ||
1082 otype == DHCPV6_OPT_SERVERID ||
1083 otype == DHCPV6_OPT_IA_TA ||
1084 otype == DHCPV6_OPT_PREF ||
1085 otype == DHCPV6_OPT_UNICAST ||
1086 otype == DHCPV6_OPT_FQDN ||
1087 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1088 passthru = false;
1089 } else {
1090 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1091 }
1092
1093 if (passthru)
1094 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1095 }
1096 }
1097
1098 if (orig != DHCPV6_MSG_INFO_REQ) {
1099 // Update refresh timers if no fatal status code was received
1100 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1101 switch (orig) {
1102 case DHCPV6_MSG_RENEW:
1103 // Send further renews if T1 is not set
1104 if (!t1)
1105 ret = -1;
1106 break;
1107 case DHCPV6_MSG_REBIND:
1108 // Send further rebinds if T1 and T2 is not set
1109 if (!t1 && !t2)
1110 ret = -1;
1111 break;
1112
1113 case DHCPV6_MSG_REQUEST:
1114 // All server candidates can be cleared if not yet bound
1115 if (!odhcp6c_is_bound())
1116 dhcpv6_clear_all_server_cand();
1117
1118 default :
1119 break;
1120 }
1121
1122 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1123 odhcp6c_clear_state(STATE_SERVER_ADDR);
1124 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1125 }
1126 }
1127 }
1128 else if (ret > 0) {
1129 // All server candidates can be cleared if not yet bound
1130 if (!odhcp6c_is_bound())
1131 dhcpv6_clear_all_server_cand();
1132
1133 t1 = refresh;
1134 }
1135
1136 return ret;
1137 }
1138
1139
1140 static int dhcpv6_parse_ia(void *opt, void *end)
1141 {
1142 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1143 int parsed_ia = 0;
1144 uint32_t t1, t2;
1145 uint16_t otype, olen;
1146 uint8_t *odata;
1147
1148 t1 = ntohl(ia_hdr->t1);
1149 t2 = ntohl(ia_hdr->t2);
1150
1151 if (t1 > t2)
1152 return 0;
1153
1154 // Update address IA
1155 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1156 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1157 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1158
1159 entry.iaid = ia_hdr->iaid;
1160
1161 if (otype == DHCPV6_OPT_IA_PREFIX) {
1162 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1163 if (olen + 4U < sizeof(*prefix))
1164 continue;
1165
1166 entry.valid = ntohl(prefix->valid);
1167 entry.preferred = ntohl(prefix->preferred);
1168
1169 if (entry.preferred > entry.valid)
1170 continue;
1171
1172 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1173 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1174 if (entry.t1 > entry.t2)
1175 entry.t1 = entry.t2;
1176
1177 entry.length = prefix->prefix;
1178 entry.target = prefix->addr;
1179 uint16_t stype, slen;
1180 uint8_t *sdata;
1181
1182 // Parse PD-exclude
1183 bool ok = true;
1184 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1185 odata + olen, stype, slen, sdata) {
1186 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1187 continue;
1188
1189 uint8_t elen = sdata[0];
1190 if (elen > 64)
1191 elen = 64;
1192
1193 if (entry.length < 32 || elen <= entry.length) {
1194 ok = false;
1195 continue;
1196 }
1197
1198
1199 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1200 if (slen <= bytes) {
1201 ok = false;
1202 continue;
1203 }
1204
1205 uint32_t exclude = 0;
1206 do {
1207 exclude = exclude << 8 | sdata[bytes];
1208 } while (--bytes);
1209
1210 exclude >>= 8 - ((elen - entry.length) % 8);
1211 exclude <<= 64 - elen;
1212
1213 // Abusing router & priority fields for exclusion
1214 entry.router = entry.target;
1215 entry.router.s6_addr32[1] |= htonl(exclude);
1216 entry.priority = elen;
1217 }
1218
1219 if (ok) {
1220 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1221 parsed_ia++;
1222 }
1223
1224 entry.priority = 0;
1225 memset(&entry.router, 0, sizeof(entry.router));
1226 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1227 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1228 if (olen + 4U < sizeof(*addr))
1229 continue;
1230
1231 entry.preferred = ntohl(addr->preferred);
1232 entry.valid = ntohl(addr->valid);
1233
1234 if (entry.preferred > entry.valid)
1235 continue;
1236
1237 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1238 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1239 if (entry.t1 > entry.t2)
1240 entry.t1 = entry.t2;
1241
1242 entry.length = 128;
1243 entry.target = addr->addr;
1244
1245 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1246 parsed_ia++;
1247 }
1248 }
1249 return parsed_ia;
1250 }
1251
1252
1253 static int dhcpv6_calc_refresh_timers(void)
1254 {
1255 struct odhcp6c_entry *e;
1256 size_t ia_na_entries, ia_pd_entries, i;
1257 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1258
1259 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1260 ia_na_entries /= sizeof(*e);
1261 for (i = 0; i < ia_na_entries; i++) {
1262 if (e[i].t1 < l_t1)
1263 l_t1 = e[i].t1;
1264
1265 if (e[i].t2 < l_t2)
1266 l_t2 = e[i].t2;
1267
1268 if (e[i].valid > l_t3)
1269 l_t3 = e[i].valid;
1270 }
1271
1272 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1273 ia_pd_entries /= sizeof(*e);
1274 for (i = 0; i < ia_pd_entries; i++) {
1275 if (e[i].t1 < l_t1)
1276 l_t1 = e[i].t1;
1277
1278 if (e[i].t2 < l_t2)
1279 l_t2 = e[i].t2;
1280
1281 if (e[i].valid > l_t3)
1282 l_t3 = e[i].valid;
1283 }
1284
1285 if (ia_pd_entries || ia_na_entries) {
1286 t1 = l_t1;
1287 t2 = l_t2;
1288 t3 = l_t3;
1289 } else {
1290 t1 = 600;
1291 }
1292
1293 return (int)(ia_pd_entries + ia_na_entries);
1294 }
1295
1296
1297 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1298 const void *status_msg, int len)
1299 {
1300 const char *src = status_msg;
1301 char buf[len + 3];
1302 char *dst = buf;
1303
1304 if (len) {
1305 *dst++ = '(';
1306 while (len--) {
1307 *dst = isprint((unsigned char)*src) ? *src : '?';
1308 src++;
1309 dst++;
1310 }
1311 *dst++ = ')';
1312 }
1313 *dst = 0;
1314
1315 syslog(LOG_WARNING, "Server returned %s status %i %s",
1316 scope, code, buf);
1317 }
1318
1319
1320 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1321 const uint16_t code, const void *status_msg, const int len,
1322 int *ret)
1323 {
1324 dhcpv6_log_status_code(code, "message", status_msg, len);
1325
1326 switch (code) {
1327 case DHCPV6_UnspecFail:
1328 // Generic failure
1329 *ret = 0;
1330 break;
1331
1332 case DHCPV6_UseMulticast:
1333 // TODO handle multicast status code
1334 break;
1335
1336 case DHCPV6_NoAddrsAvail:
1337 case DHCPV6_NoPrefixAvail:
1338 if (orig == DHCPV6_MSG_REQUEST)
1339 *ret = 0; // Failure
1340 break;
1341
1342 default:
1343 break;
1344 }
1345 }
1346
1347
1348 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1349 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1350 const void *status_msg, const int len,
1351 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1352 {
1353 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1354 "IA_NA" : "IA_PD", status_msg, len);
1355
1356 switch (code) {
1357 case DHCPV6_NoBinding:
1358 switch (orig) {
1359 case DHCPV6_MSG_RENEW:
1360 case DHCPV6_MSG_REBIND:
1361 if ((*ret > 0) && !handled_status_codes[code])
1362 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1363 break;
1364
1365 default:
1366 break;
1367 }
1368 break;
1369
1370 default:
1371 *ret = 0;
1372 break;
1373 }
1374 }
1375
1376 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1377 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1378 {
1379 size_t cand_len, i;
1380 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1381
1382 // Remove identical duid server candidate
1383 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1384 if (cand->duid_len == c[i].duid_len &&
1385 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1386 free(c[i].ia_na);
1387 free(c[i].ia_pd);
1388 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1389 break;
1390 }
1391 }
1392
1393 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1394 i < cand_len / sizeof(*c); ++i) {
1395 if (c[i].preference < cand->preference)
1396 break;
1397 }
1398
1399 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1400 free(cand->ia_na);
1401 free(cand->ia_pd);
1402 }
1403 }
1404
1405 static void dhcpv6_clear_all_server_cand(void)
1406 {
1407 size_t cand_len, i;
1408 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1409
1410 // Server candidates need deep delete for IA_NA/IA_PD
1411 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1412 free(c[i].ia_na);
1413 free(c[i].ia_pd);
1414 }
1415 odhcp6c_clear_state(STATE_SERVER_CAND);
1416 }
1417
1418 int dhcpv6_promote_server_cand(void)
1419 {
1420 size_t cand_len;
1421 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1422 uint16_t hdr[2];
1423 int ret = DHCPV6_STATELESS;
1424
1425 // Clear lingering candidate state info
1426 odhcp6c_clear_state(STATE_SERVER_ID);
1427 odhcp6c_clear_state(STATE_IA_NA);
1428 odhcp6c_clear_state(STATE_IA_PD);
1429
1430 if (!cand_len)
1431 return -1;
1432
1433 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1434 na_mode = IA_MODE_NONE;
1435
1436 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1437 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1438
1439 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1440 }
1441
1442 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1443 hdr[1] = htons(cand->duid_len);
1444 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1445 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1446 accept_reconfig = cand->wants_reconfigure;
1447 if (cand->ia_na_len) {
1448 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1449 free(cand->ia_na);
1450 if (na_mode != IA_MODE_NONE)
1451 ret = DHCPV6_STATEFUL;
1452 }
1453 if (cand->ia_pd_len) {
1454 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1455 free(cand->ia_pd);
1456 if (request_prefix)
1457 ret = DHCPV6_STATEFUL;
1458 }
1459
1460 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1461 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1462
1463 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1464
1465 return ret;
1466 }
Openwrt DHCPv6 Client