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