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[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 */
15
16 #include <time.h>
17 #include <fcntl.h>
18 #include <errno.h>
19 #include <inttypes.h>
20 #include <stdlib.h>
21 #include <signal.h>
22 #include <limits.h>
23 #include <resolv.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <syslog.h>
27 #include <stdbool.h>
28 #include <ctype.h>
29 #include <sys/time.h>
30 #include <sys/ioctl.h>
31 #include <sys/socket.h>
32 #include <arpa/inet.h>
33 #include <netinet/in.h>
34
35 #include <net/if.h>
36 #include <net/ethernet.h>
37
38 #include "odhcp6c.h"
39 #ifdef USE_LIBUBOX
40 #include <libubox/md5.h>
41 #else
42 #include "md5.h"
43 #endif
44
45
46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
47 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
48 #define DHCPV6_CLIENT_PORT 546
49 #define DHCPV6_SERVER_PORT 547
50 #define DHCPV6_DUID_LLADDR 3
51 #define DHCPV6_REQ_DELAY 1
52
53 #define DHCPV6_SOL_MAX_RT_MIN 60
54 #define DHCPV6_SOL_MAX_RT_MAX 86400
55 #define DHCPV6_INF_MAX_RT_MIN 60
56 #define DHCPV6_INF_MAX_RT_MAX 86400
57
58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
59 const uint8_t transaction[3], enum dhcpv6_msg type,
60 const struct in6_addr *daddr);
61
62 static int dhcpv6_parse_ia(void *opt, void *end);
63
64 static int dhcpv6_calc_refresh_timers(void);
65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
66 const uint16_t code, const void *status_msg, const int len,
67 int *ret);
68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
69 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
70 const void *status_msg, const int len,
71 bool handled_status_codes[_DHCPV6_Status_Max],
72 int *ret);
73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
74 static void dhcpv6_clear_all_server_cand(void);
75
76 static reply_handler dhcpv6_handle_reply;
77 static reply_handler dhcpv6_handle_advert;
78 static reply_handler dhcpv6_handle_rebind_reply;
79 static reply_handler dhcpv6_handle_reconfigure;
80 static int dhcpv6_commit_advert(void);
81
82 // RFC 3315 - 5.5 Timeout and Delay values
83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
84 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
85 dhcpv6_handle_reconfigure, NULL},
86 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
87 dhcpv6_handle_advert, dhcpv6_commit_advert},
88 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
89 dhcpv6_handle_reply, NULL},
90 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
91 dhcpv6_handle_reply, NULL},
92 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
93 dhcpv6_handle_rebind_reply, NULL},
94 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
95 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
96 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
97 dhcpv6_handle_reply, NULL},
98 };
99
100 // Sockets
101 static int sock = -1;
102 static int ifindex = -1;
103 static int64_t t1 = 0, t2 = 0, t3 = 0;
104
105 // IA states
106 static int request_prefix = -1;
107 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
108 static bool accept_reconfig = false;
109 // Server unicast address
110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
111
112 // Reconfigure key
113 static uint8_t reconf_key[16];
114
115 // client options
116 static unsigned int client_options = 0;
117
118 static uint32_t ntohl_unaligned(const uint8_t *data)
119 {
120 uint32_t buf;
121
122 memcpy(&buf, data, sizeof(buf));
123 return ntohl(buf);
124 }
125
126 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
127 {
128 client_options = options;
129 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
130
131 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
132 if (sock < 0)
133 return -1;
134
135 // Detect interface
136 struct ifreq ifr;
137 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
138 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
139 return -1;
140
141 ifindex = ifr.ifr_ifindex;
142
143 // Create client DUID
144 size_t client_id_len;
145 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
146 if (client_id_len == 0) {
147 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
148 DHCPV6_DUID_LLADDR, 0, 1};
149
150 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
151 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
152
153 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
154 struct ifreq ifs[100], *ifp, *ifend;
155 struct ifconf ifc;
156 ifc.ifc_req = ifs;
157 ifc.ifc_len = sizeof(ifs);
158
159 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
160 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
161 // If our interface doesn't have an address...
162 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
163 for (ifp = ifc.ifc_req; ifp < ifend &&
164 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
165 memcpy(ifr.ifr_name, ifp->ifr_name,
166 sizeof(ifr.ifr_name));
167 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
168 continue;
169
170 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
171 ETHER_ADDR_LEN);
172 }
173 }
174
175 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
176 }
177
178 // Create ORO
179 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
180 uint16_t oro[] = {
181 htons(DHCPV6_OPT_SIP_SERVER_D),
182 htons(DHCPV6_OPT_SIP_SERVER_A),
183 htons(DHCPV6_OPT_DNS_SERVERS),
184 htons(DHCPV6_OPT_DNS_DOMAIN),
185 htons(DHCPV6_OPT_UNICAST),
186 htons(DHCPV6_OPT_SNTP_SERVERS),
187 htons(DHCPV6_OPT_NTP_SERVER),
188 htons(DHCPV6_OPT_AFTR_NAME),
189 htons(DHCPV6_OPT_PD_EXCLUDE),
190 htons(DHCPV6_OPT_SOL_MAX_RT),
191 htons(DHCPV6_OPT_INF_MAX_RT),
192 #ifdef EXT_CER_ID
193 htons(DHCPV6_OPT_CER_ID),
194 #endif
195 htons(DHCPV6_OPT_S46_CONT_MAPE),
196 htons(DHCPV6_OPT_S46_CONT_MAPT),
197 htons(DHCPV6_OPT_S46_CONT_LW),
198 };
199 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
200 }
201
202 // Configure IPv6-options
203 int val = 1;
204 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
205 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
206 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
207 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
208
209 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
210 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
211
212 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
213 return -1;
214
215 return 0;
216 }
217
218 enum {
219 IOV_HDR=0,
220 IOV_ORO,
221 IOV_ORO_REFRESH,
222 IOV_CL_ID,
223 IOV_SRV_ID,
224 IOV_VENDOR_CLASS_HDR,
225 IOV_VENDOR_CLASS,
226 IOV_USER_CLASS_HDR,
227 IOV_USER_CLASS,
228 IOV_OPTS,
229 IOV_RECONF_ACCEPT,
230 IOV_FQDN,
231 IOV_HDR_IA_NA,
232 IOV_IA_NA,
233 IOV_IA_PD,
234 IOV_TOTAL
235 };
236
237 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
238 {
239 int mode = DHCPV6_UNKNOWN;
240
241 na_mode = na;
242 pd_mode = pd;
243
244 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
245 mode = DHCPV6_STATELESS;
246 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
247 mode = DHCPV6_STATEFUL;
248
249 return mode;
250 }
251
252 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
253 {
254 // Build FQDN
255 char fqdn_buf[256];
256 gethostname(fqdn_buf, sizeof(fqdn_buf));
257 struct {
258 uint16_t type;
259 uint16_t len;
260 uint8_t flags;
261 uint8_t data[256];
262 } fqdn;
263 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
264 sizeof(fqdn.data), NULL, NULL);
265 fqdn.type = htons(DHCPV6_OPT_FQDN);
266 fqdn.len = htons(fqdn_len - 4);
267 fqdn.flags = 0;
268
269 // Build Client ID
270 size_t cl_id_len;
271 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
272
273 // Get Server ID
274 size_t srv_id_len;
275 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
276
277 // Build IA_PDs
278 size_t ia_pd_entries = 0, ia_pd_len = 0;
279 uint8_t *ia_pd;
280
281 if (type == DHCPV6_MSG_SOLICIT) {
282 odhcp6c_clear_state(STATE_IA_PD);
283 size_t n_prefixes;
284 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
285 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
286
287 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
288
289 for (size_t i = 0; i < n_prefixes; i++) {
290 struct dhcpv6_ia_hdr hdr_ia_pd = {
291 htons(DHCPV6_OPT_IA_PD),
292 htons(sizeof(hdr_ia_pd) - 4 +
293 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
294 request_prefixes[i].iaid, 0, 0
295 };
296 struct dhcpv6_ia_prefix pref = {
297 .type = htons(DHCPV6_OPT_IA_PREFIX),
298 .len = htons(sizeof(pref) - 4),
299 .prefix = request_prefixes[i].length
300 };
301 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
302 ia_pd_len += sizeof(hdr_ia_pd);
303 if (request_prefixes[i].length) {
304 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
305 ia_pd_len += sizeof(pref);
306 }
307 }
308 } else {
309 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
310 ia_pd_entries /= sizeof(*e);
311
312 // we're too lazy to count our distinct IAIDs,
313 // so just allocate maximally needed space
314 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
315 sizeof(struct dhcpv6_ia_hdr)));
316
317 for (size_t i = 0; i < ia_pd_entries; ++i) {
318 uint32_t iaid = e[i].iaid;
319
320 // check if this is an unprocessed IAID and skip if not.
321 int new_iaid = 1;
322 for (int j = i-1; j >= 0; j--) {
323 if (e[j].iaid == iaid) {
324 new_iaid = 0;
325 break;
326 }
327 }
328
329 if (!new_iaid)
330 continue;
331
332 // construct header
333 struct dhcpv6_ia_hdr hdr_ia_pd = {
334 htons(DHCPV6_OPT_IA_PD),
335 htons(sizeof(hdr_ia_pd) - 4),
336 iaid, 0, 0
337 };
338
339 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
340 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
341 ia_pd_len += sizeof(hdr_ia_pd);
342
343 for (size_t j = i; j < ia_pd_entries; j++) {
344 if (e[j].iaid != iaid)
345 continue;
346
347 uint8_t ex_len = 0;
348 if (e[j].priority > 0)
349 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
350
351 struct dhcpv6_ia_prefix p = {
352 .type = htons(DHCPV6_OPT_IA_PREFIX),
353 .len = htons(sizeof(p) - 4U + ex_len),
354 .prefix = e[j].length,
355 .addr = e[j].target
356 };
357
358 if (type == DHCPV6_MSG_REQUEST) {
359 p.preferred = htonl(e[j].preferred);
360 p.valid = htonl(e[j].valid);
361 }
362
363 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
364 ia_pd_len += sizeof(p);
365
366 if (ex_len) {
367 ia_pd[ia_pd_len++] = 0;
368 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
369 ia_pd[ia_pd_len++] = 0;
370 ia_pd[ia_pd_len++] = ex_len - 4;
371 ia_pd[ia_pd_len++] = e[j].priority;
372
373 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
374 excl >>= (64 - e[j].priority);
375 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
376
377 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
378 ia_pd[ia_pd_len + i] = excl & 0xff;
379 ia_pd_len += ex_len - 5;
380 }
381
382 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
383 }
384 }
385 }
386
387 if (ia_pd_entries > 0)
388 request_prefix = 1;
389
390 // Build IA_NAs
391 size_t ia_na_entries, ia_na_len = 0;
392 void *ia_na = NULL;
393 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
394 ia_na_entries /= sizeof(*e);
395
396 struct dhcpv6_ia_hdr hdr_ia_na = {
397 htons(DHCPV6_OPT_IA_NA),
398 htons(sizeof(hdr_ia_na) - 4),
399 htonl(1), 0, 0
400 };
401
402 struct dhcpv6_ia_addr pa[ia_na_entries];
403 for (size_t i = 0; i < ia_na_entries; ++i) {
404 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
405 pa[i].len = htons(sizeof(pa[i]) - 4U);
406 pa[i].addr = e[i].target;
407
408 if (type == DHCPV6_MSG_REQUEST) {
409 pa[i].preferred = htonl(e[i].preferred);
410 pa[i].valid = htonl(e[i].valid);
411 } else {
412 pa[i].preferred = 0;
413 pa[i].valid = 0;
414 }
415 }
416
417 ia_na = pa;
418 ia_na_len = sizeof(pa);
419 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
420
421 // Reconfigure Accept
422 struct {
423 uint16_t type;
424 uint16_t length;
425 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
426
427 // Request Information Refresh
428 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
429
430 // Option list
431 size_t opts_len;
432 void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
433
434 // Build vendor-class option
435 size_t vendor_class_len, user_class_len;
436 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
437 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
438
439 struct {
440 uint16_t type;
441 uint16_t length;
442 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
443
444 struct {
445 uint16_t type;
446 uint16_t length;
447 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
448
449 // Prepare Header
450 size_t oro_len;
451 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
452 struct {
453 uint8_t type;
454 uint8_t trid[3];
455 uint16_t elapsed_type;
456 uint16_t elapsed_len;
457 uint16_t elapsed_value;
458 uint16_t oro_type;
459 uint16_t oro_len;
460 } hdr = {
461 type, {trid[0], trid[1], trid[2]},
462 htons(DHCPV6_OPT_ELAPSED), htons(2),
463 htons((ecs > 0xffff) ? 0xffff : ecs),
464 htons(DHCPV6_OPT_ORO), htons(oro_len),
465 };
466
467 struct iovec iov[IOV_TOTAL] = {
468 [IOV_HDR] = {&hdr, sizeof(hdr)},
469 [IOV_ORO] = {oro, oro_len},
470 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
471 [IOV_CL_ID] = {cl_id, cl_id_len},
472 [IOV_SRV_ID] = {srv_id, srv_id_len},
473 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
474 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
475 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
476 [IOV_USER_CLASS] = {user_class, user_class_len},
477 [IOV_OPTS] = { opts, opts_len },
478 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
479 [IOV_FQDN] = {&fqdn, fqdn_len},
480 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
481 [IOV_IA_NA] = {ia_na, ia_na_len},
482 [IOV_IA_PD] = {ia_pd, ia_pd_len},
483 };
484
485 size_t cnt = IOV_TOTAL;
486 if (type == DHCPV6_MSG_INFO_REQ) {
487 cnt = 9;
488 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
489 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
490 } else if (!request_prefix)
491 cnt = 13;
492
493 // Disable IAs if not used
494 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
495 iov[IOV_HDR_IA_NA].iov_len = 0;
496
497 if (na_mode == IA_MODE_NONE)
498 iov[IOV_HDR_IA_NA].iov_len = 0;
499
500 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
501 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
502 iov[IOV_RECONF_ACCEPT].iov_len = 0;
503
504 if (!(client_options & DHCPV6_CLIENT_FQDN))
505 iov[IOV_FQDN].iov_len = 0;
506
507 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
508 0, ALL_DHCPV6_RELAYS, ifindex};
509 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
510 .msg_iov = iov, .msg_iovlen = cnt};
511
512 switch (type) {
513 case DHCPV6_MSG_REQUEST:
514 case DHCPV6_MSG_RENEW:
515 case DHCPV6_MSG_RELEASE:
516 case DHCPV6_MSG_DECLINE:
517 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
518 odhcp6c_addr_in_scope(&server_addr)) {
519 srv.sin6_addr = server_addr;
520 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
521 srv.sin6_scope_id = 0;
522 }
523 break;
524 default:
525 break;
526 }
527
528 if (sendmsg(sock, &msg, 0) < 0) {
529 char in6_str[INET6_ADDRSTRLEN];
530
531 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
532 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
533 in6_str, sizeof(in6_str)), strerror(errno));
534 }
535 }
536
537 static int64_t dhcpv6_rand_delay(int64_t time)
538 {
539 int random;
540 odhcp6c_random(&random, sizeof(random));
541
542 return (time * ((int64_t)random % 1000LL)) / 10000LL;
543 }
544
545 int dhcpv6_request(enum dhcpv6_msg type)
546 {
547 uint8_t rc = 0;
548 uint64_t timeout = UINT32_MAX;
549 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
550
551 if (retx->delay) {
552 struct timespec ts = {0, 0};
553 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
554
555 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
556 }
557
558 if (type == DHCPV6_MSG_UNKNOWN)
559 timeout = t1;
560 else if (type == DHCPV6_MSG_RENEW)
561 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
562 else if (type == DHCPV6_MSG_REBIND)
563 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
564
565 if (timeout == 0)
566 return -1;
567
568 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
569 retx->name, timeout, retx->max_rc);
570
571 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
572
573 // Generate transaction ID
574 uint8_t trid[3] = {0, 0, 0};
575 if (type != DHCPV6_MSG_UNKNOWN)
576 odhcp6c_random(trid, sizeof(trid));
577
578 ssize_t len = -1;
579 int64_t rto = 0;
580
581 do {
582 if (rto == 0) {
583 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
584
585 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
586 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
587 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
588
589 rto = (retx->init_timeo * 1000 + delay);
590 } else
591 rto = (2 * rto + dhcpv6_rand_delay(rto));
592
593 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
594 rto = retx->max_timeo * 1000 +
595 dhcpv6_rand_delay(retx->max_timeo * 1000);
596
597 // Calculate end for this round and elapsed time
598 uint64_t round_end = round_start + rto;
599 elapsed = round_start - start;
600
601 // Don't wait too long if timeout differs from infinite
602 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
603 round_end = timeout * 1000 + start;
604
605 // Built and send package
606 switch (type) {
607 case DHCPV6_MSG_UNKNOWN:
608 break;
609 default:
610 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
611 retx->name, elapsed, rc);
612 // Fall through
613 case DHCPV6_MSG_SOLICIT:
614 case DHCPV6_MSG_INFO_REQ:
615 dhcpv6_send(type, trid, elapsed / 10);
616 rc++;
617 }
618
619 // Receive rounds
620 for (; len < 0 && (round_start < round_end);
621 round_start = odhcp6c_get_milli_time()) {
622 uint8_t buf[1536];
623 union {
624 struct cmsghdr hdr;
625 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
626 } cmsg_buf;
627 struct iovec iov = {buf, sizeof(buf)};
628 struct sockaddr_in6 addr;
629 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
630 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
631 .msg_controllen = sizeof(cmsg_buf)};
632 struct in6_pktinfo *pktinfo = NULL;
633
634 // Check for pending signal
635 if (odhcp6c_signal_process())
636 return -1;
637
638 // Set timeout for receiving
639 uint64_t t = round_end - round_start;
640 struct timeval tv = {t / 1000, (t % 1000) * 1000};
641 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
642 &tv, sizeof(tv));
643
644 // Receive cycle
645 len = recvmsg(sock, &msg, 0);
646 if (len < 0)
647 continue;
648
649 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
650 ch = CMSG_NXTHDR(&msg, ch)) {
651 if (ch->cmsg_level == SOL_IPV6 &&
652 ch->cmsg_type == IPV6_PKTINFO) {
653 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
654 break;
655 }
656 }
657
658 if (pktinfo == NULL) {
659 len = -1;
660 continue;
661 }
662
663 if (!dhcpv6_response_is_valid(buf, len, trid,
664 type, &pktinfo->ipi6_addr)) {
665 len = -1;
666 continue;
667 }
668
669 uint8_t *opt = &buf[4];
670 uint8_t *opt_end = opt + len - 4;
671
672 round_start = odhcp6c_get_milli_time();
673 elapsed = round_start - start;
674 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
675 elapsed);
676
677 if (retx->handler_reply)
678 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
679
680 if (len > 0 && round_end - round_start > 1000)
681 round_end = 1000 + round_start;
682 }
683
684 // Allow
685 if (retx->handler_finish)
686 len = retx->handler_finish();
687 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
688 (!retx->max_rc || rc < retx->max_rc));
689 return len;
690 }
691
692 // Message validation checks according to RFC3315 chapter 15
693 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
694 const uint8_t transaction[3], enum dhcpv6_msg type,
695 const struct in6_addr *daddr)
696 {
697 const struct dhcpv6_header *rep = buf;
698 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
699 transaction, sizeof(rep->tr_id)))
700 return false; // Invalid reply
701
702 if (type == DHCPV6_MSG_SOLICIT) {
703 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
704 rep->msg_type != DHCPV6_MSG_REPLY)
705 return false;
706
707 } else if (type == DHCPV6_MSG_UNKNOWN) {
708 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
709 return false;
710
711 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
712 return false;
713
714 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
715 rcmsg = DHCPV6_MSG_UNKNOWN;
716 uint16_t otype, olen = UINT16_MAX;
717 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
718 ia_present = false, options_valid = true;
719
720 size_t client_id_len, server_id_len;
721 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
722 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
723
724 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
725 if (otype == DHCPV6_OPT_CLIENTID) {
726 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
727 &odata[-4], client_id, client_id_len);
728 } else if (otype == DHCPV6_OPT_SERVERID) {
729 if (server_id_len)
730 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
731 &odata[-4], server_id, server_id_len);
732 else
733 serverid_ok = true;
734 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
735 sizeof(struct dhcpv6_auth_reconfigure)) {
736 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
737 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
738 continue;
739
740 md5_ctx_t md5;
741 uint8_t serverhash[16], secretbytes[64];
742 uint32_t hash[4];
743 memcpy(serverhash, r->key, sizeof(serverhash));
744 memset(r->key, 0, sizeof(r->key));
745
746 memset(secretbytes, 0, sizeof(secretbytes));
747 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
748
749 for (size_t i = 0; i < sizeof(secretbytes); ++i)
750 secretbytes[i] ^= 0x36;
751
752 md5_begin(&md5);
753 md5_hash(secretbytes, sizeof(secretbytes), &md5);
754 md5_hash(buf, len, &md5);
755 md5_end(hash, &md5);
756
757 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
758 secretbytes[i] ^= 0x36;
759 secretbytes[i] ^= 0x5c;
760 }
761
762 md5_begin(&md5);
763 md5_hash(secretbytes, sizeof(secretbytes), &md5);
764 md5_hash(hash, 16, &md5);
765 md5_end(hash, &md5);
766
767 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
768 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
769 rcmsg = odata[0];
770 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
771 ia_present = true;
772 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
773 options_valid = false;
774 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
775 (otype == DHCPV6_OPT_PD_EXCLUDE))
776 // Options are not allowed on global level
777 options_valid = false;
778 }
779
780 if (!options_valid || ((odata + olen) > end))
781 return false;
782
783 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
784 return false;
785
786 if (rep->msg_type == DHCPV6_MSG_RECONF) {
787 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
788 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
789 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
790 return false;
791 }
792
793 return clientid_ok && serverid_ok;
794 }
795
796 int dhcpv6_poll_reconfigure(void)
797 {
798 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
799
800 if (ret != -1)
801 ret = dhcpv6_request(ret);
802
803 return ret;
804 }
805
806 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
807 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
808 {
809 uint16_t otype, olen;
810 uint8_t *odata;
811 int msg = -1;
812
813 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
814 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
815 switch (odata[0]) {
816 case DHCPV6_MSG_REBIND:
817 if (t2 != UINT32_MAX)
818 t2 = 0;
819 // Fall through
820 case DHCPV6_MSG_RENEW:
821 if (t1 != UINT32_MAX)
822 t1 = 0;
823 // Fall through
824 case DHCPV6_MSG_INFO_REQ:
825 msg = odata[0];
826 break;
827
828 default:
829 break;
830 }
831 }
832 }
833
834 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
835
836 return msg;
837 }
838
839 // Collect all advertised servers
840 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
841 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
842 {
843 uint16_t olen, otype;
844 uint8_t *odata, pref = 0;
845 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
846 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
847 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
848 bool have_na = false;
849 int have_pd = 0;
850
851 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
852 if (orig == DHCPV6_MSG_SOLICIT &&
853 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
854 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
855 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
856 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
857 }
858
859 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
860 memcpy(cand.duid, odata, olen);
861 cand.duid_len = olen;
862 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
863 cand.preference >= 0) {
864 cand.preference = pref = odata[0];
865 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
866 cand.server_addr = *(struct in6_addr *)odata;
867 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
868 cand.wants_reconfigure = true;
869 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
870 uint32_t sol_max_rt = ntohl_unaligned(odata);
871 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
872 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
873 cand.sol_max_rt = sol_max_rt;
874
875 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
876 uint32_t inf_max_rt = ntohl_unaligned(odata);
877 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
878 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
879 cand.inf_max_rt = inf_max_rt;
880
881 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
882 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
883 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
884 uint8_t *oend = odata + olen, *d;
885 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
886 if (otype == DHCPV6_OPT_IA_PREFIX &&
887 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
888 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
889 have_pd = p->prefix;
890 }
891 }
892 } else if (otype == DHCPV6_OPT_IA_NA &&
893 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
894 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
895 uint8_t *oend = odata + olen, *d;
896
897 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
898 if (otype == DHCPV6_OPT_IA_ADDR &&
899 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
900 have_na = true;
901 }
902 }
903 }
904
905 if ((!have_na && na_mode == IA_MODE_FORCE) ||
906 (!have_pd && pd_mode == IA_MODE_FORCE)) {
907 /*
908 * RFC7083 states to process the SOL_MAX_RT and
909 * INF_MAX_RT options even if the DHCPv6 server
910 * did not propose any IA_NA and/or IA_PD
911 */
912 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
913 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
914 return -1;
915 }
916
917 if (na_mode != IA_MODE_NONE && !have_na) {
918 cand.has_noaddravail = true;
919 cand.preference -= 1000;
920 }
921
922 if (pd_mode != IA_MODE_NONE) {
923 if (have_pd)
924 cand.preference += 2000 + (128 - have_pd);
925 else
926 cand.preference -= 2000;
927 }
928
929 if (cand.duid_len > 0) {
930 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
931 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
932 dhcpv6_add_server_cand(&cand);
933 }
934
935 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
936 }
937
938 static int dhcpv6_commit_advert(void)
939 {
940 return dhcpv6_promote_server_cand();
941 }
942
943 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
944 const void *opt, const void *end, const struct sockaddr_in6 *from)
945 {
946 dhcpv6_handle_advert(orig, rc, opt, end, from);
947 if (dhcpv6_commit_advert() < 0)
948 return -1;
949
950 return dhcpv6_handle_reply(orig, rc, opt, end, from);
951 }
952
953 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
954 const void *opt, const void *end, const struct sockaddr_in6 *from)
955 {
956 uint8_t *odata;
957 uint16_t otype, olen;
958 uint32_t refresh = 86400;
959 int ret = 1;
960 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
961
962 odhcp6c_expire();
963
964 if (orig == DHCPV6_MSG_UNKNOWN) {
965 static time_t last_update = 0;
966 time_t now = odhcp6c_get_milli_time() / 1000;
967
968 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
969 last_update = now;
970
971 if (t1 != UINT32_MAX)
972 t1 -= elapsed;
973
974 if (t2 != UINT32_MAX)
975 t2 -= elapsed;
976
977 if (t3 != UINT32_MAX)
978 t3 -= elapsed;
979
980 if (t1 < 0)
981 t1 = 0;
982
983 if (t2 < 0)
984 t2 = 0;
985
986 if (t3 < 0)
987 t3 = 0;
988 }
989
990 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
991 // Delete NA and PD we have in the state from the Advert
992 odhcp6c_clear_state(STATE_IA_NA);
993 odhcp6c_clear_state(STATE_IA_PD);
994 }
995
996 if (opt) {
997 odhcp6c_clear_state(STATE_DNS);
998 odhcp6c_clear_state(STATE_SEARCH);
999 odhcp6c_clear_state(STATE_SNTP_IP);
1000 odhcp6c_clear_state(STATE_NTP_IP);
1001 odhcp6c_clear_state(STATE_NTP_FQDN);
1002 odhcp6c_clear_state(STATE_SIP_IP);
1003 odhcp6c_clear_state(STATE_SIP_FQDN);
1004 odhcp6c_clear_state(STATE_AFTR_NAME);
1005 odhcp6c_clear_state(STATE_CER);
1006 odhcp6c_clear_state(STATE_S46_MAPT);
1007 odhcp6c_clear_state(STATE_S46_MAPE);
1008 odhcp6c_clear_state(STATE_S46_LW);
1009 odhcp6c_clear_state(STATE_PASSTHRU);
1010 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1011
1012 // Parse and find all matching IAs
1013 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1014 bool passthru = true;
1015
1016 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1017 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1018 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1019
1020 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1021 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1022 continue;
1023
1024 // Test ID
1025 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1026 continue;
1027
1028 uint16_t code = DHCPV6_Success;
1029 uint16_t stype, slen;
1030 uint8_t *sdata;
1031 // Get and handle status code
1032 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1033 stype, slen, sdata) {
1034 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1035 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1036 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1037
1038 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1039
1040 if (code == DHCPV6_Success)
1041 continue;
1042
1043 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1044 code, mdata, mlen, handled_status_codes, &ret);
1045
1046 if (ret > 0)
1047 return ret;
1048
1049 break;
1050 }
1051 }
1052
1053 if (code != DHCPV6_Success)
1054 continue;
1055
1056 dhcpv6_parse_ia(ia_hdr, odata + olen);
1057 passthru = false;
1058 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1059 server_addr = *(struct in6_addr *)odata;
1060 passthru = false;
1061 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1062 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1063 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1064 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1065
1066 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1067 passthru = false;
1068 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1069 if (olen % 16 == 0)
1070 odhcp6c_add_state(STATE_DNS, odata, olen);
1071 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1072 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1073 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1074 if (olen % 16 == 0)
1075 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1076 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1077 uint16_t stype, slen;
1078 uint8_t *sdata;
1079 // Test status and bail if error
1080 dhcpv6_for_each_option(odata, odata + olen,
1081 stype, slen, sdata) {
1082 if (slen == 16 && (stype == NTP_MC_ADDR ||
1083 stype == NTP_SRV_ADDR))
1084 odhcp6c_add_state(STATE_NTP_IP,
1085 sdata, slen);
1086 else if (slen > 0 && stype == NTP_SRV_FQDN)
1087 odhcp6c_add_state(STATE_NTP_FQDN,
1088 sdata, slen);
1089 }
1090 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1091 if (olen == 16)
1092 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1093 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1094 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1095 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1096 refresh = ntohl_unaligned(odata);
1097 passthru = false;
1098 } else if (otype == DHCPV6_OPT_AUTH) {
1099 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1100 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1101 if (r->protocol == 3 && r->algorithm == 1 &&
1102 r->reconf_type == 1)
1103 memcpy(reconf_key, r->key, sizeof(r->key));
1104 }
1105 passthru = false;
1106 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1107 size_t cur_len;
1108 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1109 if (cur_len == 0)
1110 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1111 passthru = false;
1112 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1113 uint32_t sol_max_rt = ntohl_unaligned(odata);
1114 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1115 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1116 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1117 passthru = false;
1118 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1119 uint32_t inf_max_rt = ntohl_unaligned(odata);
1120 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1121 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1122 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1123 passthru = false;
1124 #ifdef EXT_CER_ID
1125 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1126 sizeof(struct dhcpv6_cer_id)) {
1127 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1128 struct in6_addr any = IN6ADDR_ANY_INIT;
1129 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1130 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1131 passthru = false;
1132 #endif
1133 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1134 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1135 passthru = false;
1136 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1137 size_t mape_len;
1138 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1139 if (mape_len == 0)
1140 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1141 passthru = false;
1142 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1143 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1144 passthru = false;
1145 } else if (otype == DHCPV6_OPT_CLIENTID ||
1146 otype == DHCPV6_OPT_SERVERID ||
1147 otype == DHCPV6_OPT_IA_TA ||
1148 otype == DHCPV6_OPT_PREF ||
1149 otype == DHCPV6_OPT_UNICAST ||
1150 otype == DHCPV6_OPT_FQDN ||
1151 otype == DHCPV6_OPT_RECONF_ACCEPT)
1152 passthru = false;
1153 else
1154 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1155
1156 if (passthru)
1157 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1158 }
1159 }
1160
1161 switch (orig) {
1162 case DHCPV6_MSG_REQUEST:
1163 case DHCPV6_MSG_REBIND:
1164 case DHCPV6_MSG_RENEW:
1165 // Update refresh timers if no fatal status code was received
1166 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1167 if (orig == DHCPV6_MSG_REQUEST) {
1168 // All server candidates can be cleared if not yet bound
1169 if (!odhcp6c_is_bound())
1170 dhcpv6_clear_all_server_cand();
1171
1172 odhcp6c_clear_state(STATE_SERVER_ADDR);
1173 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1174 } else if (orig == DHCPV6_MSG_RENEW) {
1175 // Send further renews if T1 is not set
1176 if (!t1)
1177 ret = -1;
1178
1179 } else if (orig == DHCPV6_MSG_REBIND) {
1180 // Send further rebinds if T1 and T2 is not set
1181 if (!t1 && !t2)
1182 ret = -1;
1183
1184 odhcp6c_clear_state(STATE_SERVER_ADDR);
1185 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1186 }
1187 }
1188 break;
1189
1190 case DHCPV6_MSG_INFO_REQ:
1191 if (ret > 0) {
1192 // All server candidates can be cleared if not yet bound
1193 if (!odhcp6c_is_bound())
1194 dhcpv6_clear_all_server_cand();
1195
1196 t1 = refresh;
1197 }
1198 break;
1199
1200 default:
1201 break;
1202 }
1203
1204 return ret;
1205 }
1206
1207 static int dhcpv6_parse_ia(void *opt, void *end)
1208 {
1209 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1210 int parsed_ia = 0;
1211 uint32_t t1, t2;
1212 uint16_t otype, olen;
1213 uint8_t *odata;
1214
1215 t1 = ntohl(ia_hdr->t1);
1216 t2 = ntohl(ia_hdr->t2);
1217
1218 if (t1 > t2)
1219 return 0;
1220
1221 // Update address IA
1222 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1223 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1224 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1225
1226 entry.iaid = ia_hdr->iaid;
1227
1228 if (otype == DHCPV6_OPT_IA_PREFIX) {
1229 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1230 if (olen + 4U < sizeof(*prefix))
1231 continue;
1232
1233 entry.valid = ntohl(prefix->valid);
1234 entry.preferred = ntohl(prefix->preferred);
1235
1236 if (entry.preferred > entry.valid)
1237 continue;
1238
1239 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1240 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1241 if (entry.t1 > entry.t2)
1242 entry.t1 = entry.t2;
1243
1244 entry.length = prefix->prefix;
1245 entry.target = prefix->addr;
1246 uint16_t stype, slen;
1247 uint8_t *sdata;
1248
1249 // Parse PD-exclude
1250 bool ok = true;
1251 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1252 odata + olen, stype, slen, sdata) {
1253 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1254 continue;
1255
1256 uint8_t elen = sdata[0];
1257 if (elen > 64)
1258 elen = 64;
1259
1260 if (entry.length < 32 || elen <= entry.length) {
1261 ok = false;
1262 continue;
1263 }
1264
1265 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1266 if (slen <= bytes) {
1267 ok = false;
1268 continue;
1269 }
1270
1271 uint32_t exclude = 0;
1272 do {
1273 exclude = exclude << 8 | sdata[bytes];
1274 } while (--bytes);
1275
1276 exclude >>= 8 - ((elen - entry.length) % 8);
1277 exclude <<= 64 - elen;
1278
1279 // Abusing router & priority fields for exclusion
1280 entry.router = entry.target;
1281 entry.router.s6_addr32[1] |= htonl(exclude);
1282 entry.priority = elen;
1283 }
1284
1285 if (ok) {
1286 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0);
1287 parsed_ia++;
1288 }
1289
1290 entry.priority = 0;
1291 memset(&entry.router, 0, sizeof(entry.router));
1292 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1293 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1294 if (olen + 4U < sizeof(*addr))
1295 continue;
1296
1297 entry.preferred = ntohl(addr->preferred);
1298 entry.valid = ntohl(addr->valid);
1299
1300 if (entry.preferred > entry.valid)
1301 continue;
1302
1303 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1304 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1305 if (entry.t1 > entry.t2)
1306 entry.t1 = entry.t2;
1307
1308 entry.length = 128;
1309 entry.target = addr->addr;
1310
1311 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0);
1312 parsed_ia++;
1313 }
1314 }
1315 return parsed_ia;
1316 }
1317
1318 static int dhcpv6_calc_refresh_timers(void)
1319 {
1320 struct odhcp6c_entry *e;
1321 size_t ia_na_entries, ia_pd_entries, i;
1322 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1323
1324 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1325 ia_na_entries /= sizeof(*e);
1326
1327 for (i = 0; i < ia_na_entries; i++) {
1328 if (e[i].t1 < l_t1)
1329 l_t1 = e[i].t1;
1330
1331 if (e[i].t2 < l_t2)
1332 l_t2 = e[i].t2;
1333
1334 if (e[i].valid > l_t3)
1335 l_t3 = e[i].valid;
1336 }
1337
1338 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1339 ia_pd_entries /= sizeof(*e);
1340
1341 for (i = 0; i < ia_pd_entries; i++) {
1342 if (e[i].t1 < l_t1)
1343 l_t1 = e[i].t1;
1344
1345 if (e[i].t2 < l_t2)
1346 l_t2 = e[i].t2;
1347
1348 if (e[i].valid > l_t3)
1349 l_t3 = e[i].valid;
1350 }
1351
1352 if (ia_pd_entries || ia_na_entries) {
1353 t1 = l_t1;
1354 t2 = l_t2;
1355 t3 = l_t3;
1356 }
1357
1358 return (int)(ia_pd_entries + ia_na_entries);
1359 }
1360
1361 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1362 const void *status_msg, int len)
1363 {
1364 const char *src = status_msg;
1365 char buf[len + 3];
1366 char *dst = buf;
1367
1368 if (len) {
1369 *dst++ = '(';
1370 while (len--) {
1371 *dst = isprint((unsigned char)*src) ? *src : '?';
1372 src++;
1373 dst++;
1374 }
1375 *dst++ = ')';
1376 }
1377
1378 *dst = 0;
1379
1380 syslog(LOG_WARNING, "Server returned %s status %i %s",
1381 scope, code, buf);
1382 }
1383
1384 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1385 const uint16_t code, const void *status_msg, const int len,
1386 int *ret)
1387 {
1388 dhcpv6_log_status_code(code, "message", status_msg, len);
1389
1390 switch (code) {
1391 case DHCPV6_UnspecFail:
1392 // Generic failure
1393 *ret = 0;
1394 break;
1395
1396 case DHCPV6_UseMulticast:
1397 switch(orig) {
1398 case DHCPV6_MSG_REQUEST:
1399 case DHCPV6_MSG_RENEW:
1400 case DHCPV6_MSG_RELEASE:
1401 case DHCPV6_MSG_DECLINE:
1402 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1403 server_addr = in6addr_any;
1404 *ret = 0;
1405 break;
1406 default:
1407 break;
1408 }
1409 break;
1410
1411 case DHCPV6_NoAddrsAvail:
1412 case DHCPV6_NoPrefixAvail:
1413 if (orig == DHCPV6_MSG_REQUEST)
1414 *ret = 0; // Failure
1415 break;
1416
1417 default:
1418 break;
1419 }
1420 }
1421
1422 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1423 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1424 const void *status_msg, const int len,
1425 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1426 {
1427 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1428 "IA_NA" : "IA_PD", status_msg, len);
1429
1430 switch (code) {
1431 case DHCPV6_NoBinding:
1432 switch (orig) {
1433 case DHCPV6_MSG_RENEW:
1434 case DHCPV6_MSG_REBIND:
1435 if ((*ret > 0) && !handled_status_codes[code])
1436 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1437 break;
1438
1439 default:
1440 break;
1441 }
1442 break;
1443
1444 default:
1445 *ret = 0;
1446 break;
1447 }
1448 }
1449
1450 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1451 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1452 {
1453 size_t cand_len, i;
1454 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1455
1456 // Remove identical duid server candidate
1457 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1458 if (cand->duid_len == c[i].duid_len &&
1459 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1460 free(c[i].ia_na);
1461 free(c[i].ia_pd);
1462 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1463 break;
1464 }
1465 }
1466
1467 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1468 i < cand_len / sizeof(*c); ++i) {
1469 if (c[i].preference < cand->preference)
1470 break;
1471 }
1472
1473 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1474 free(cand->ia_na);
1475 free(cand->ia_pd);
1476 }
1477 }
1478
1479 static void dhcpv6_clear_all_server_cand(void)
1480 {
1481 size_t cand_len, i;
1482 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1483
1484 // Server candidates need deep delete for IA_NA/IA_PD
1485 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1486 free(c[i].ia_na);
1487 free(c[i].ia_pd);
1488 }
1489 odhcp6c_clear_state(STATE_SERVER_CAND);
1490 }
1491
1492 int dhcpv6_promote_server_cand(void)
1493 {
1494 size_t cand_len;
1495 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1496 uint16_t hdr[2];
1497 int ret = DHCPV6_STATELESS;
1498
1499 // Clear lingering candidate state info
1500 odhcp6c_clear_state(STATE_SERVER_ID);
1501 odhcp6c_clear_state(STATE_IA_NA);
1502 odhcp6c_clear_state(STATE_IA_PD);
1503
1504 if (!cand_len)
1505 return -1;
1506
1507 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1508 na_mode = IA_MODE_NONE;
1509
1510 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1511 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1512
1513 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1514 }
1515
1516 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1517 hdr[1] = htons(cand->duid_len);
1518 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1519 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1520 accept_reconfig = cand->wants_reconfigure;
1521
1522 if (cand->ia_na_len) {
1523 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1524 free(cand->ia_na);
1525 if (na_mode != IA_MODE_NONE)
1526 ret = DHCPV6_STATEFUL;
1527 }
1528
1529 if (cand->ia_pd_len) {
1530 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1531 free(cand->ia_pd);
1532 if (request_prefix)
1533 ret = DHCPV6_STATEFUL;
1534 }
1535
1536 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1537 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1538
1539 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1540
1541 return ret;
1542 }
Openwrt DHCPv6 Client