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dhcpv6: calculate T1, T2 and T3 in a more sane manner
[project/odhcp6c.git] / src / dhcpv6.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2017 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_RECONF_ACCEPT,
229 IOV_FQDN,
230 IOV_HDR_IA_NA,
231 IOV_IA_NA,
232 IOV_IA_PD,
233 IOV_TOTAL
234 };
235
236 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
237 {
238 int mode = DHCPV6_UNKNOWN;
239
240 na_mode = na;
241 pd_mode = pd;
242
243 if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
244 mode = DHCPV6_STATELESS;
245 else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
246 mode = DHCPV6_STATEFUL;
247
248 return mode;
249 }
250
251 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
252 {
253 // Build FQDN
254 char fqdn_buf[256];
255 gethostname(fqdn_buf, sizeof(fqdn_buf));
256 struct {
257 uint16_t type;
258 uint16_t len;
259 uint8_t flags;
260 uint8_t data[256];
261 } fqdn;
262 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
263 sizeof(fqdn.data), NULL, NULL);
264 fqdn.type = htons(DHCPV6_OPT_FQDN);
265 fqdn.len = htons(fqdn_len - 4);
266 fqdn.flags = 0;
267
268 // Build Client ID
269 size_t cl_id_len;
270 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
271
272 // Get Server ID
273 size_t srv_id_len;
274 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
275
276 // Build IA_PDs
277 size_t ia_pd_entries = 0, ia_pd_len = 0;
278 uint8_t *ia_pd;
279
280 if (type == DHCPV6_MSG_SOLICIT) {
281 odhcp6c_clear_state(STATE_IA_PD);
282 size_t n_prefixes;
283 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
284 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
285
286 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
287
288 for (size_t i = 0; i < n_prefixes; i++) {
289 struct dhcpv6_ia_hdr hdr_ia_pd = {
290 htons(DHCPV6_OPT_IA_PD),
291 htons(sizeof(hdr_ia_pd) - 4 +
292 sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
293 request_prefixes[i].iaid, 0, 0
294 };
295 struct dhcpv6_ia_prefix pref = {
296 .type = htons(DHCPV6_OPT_IA_PREFIX),
297 .len = htons(sizeof(pref) - 4),
298 .prefix = request_prefixes[i].length
299 };
300 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
301 ia_pd_len += sizeof(hdr_ia_pd);
302 if (request_prefixes[i].length) {
303 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
304 ia_pd_len += sizeof(pref);
305 }
306 }
307 } else {
308 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
309 ia_pd_entries /= sizeof(*e);
310
311 // we're too lazy to count our distinct IAIDs,
312 // so just allocate maximally needed space
313 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
314 sizeof(struct dhcpv6_ia_hdr)));
315
316 for (size_t i = 0; i < ia_pd_entries; ++i) {
317 uint32_t iaid = e[i].iaid;
318
319 // check if this is an unprocessed IAID and skip if not.
320 int new_iaid = 1;
321 for (int j = i-1; j >= 0; j--) {
322 if (e[j].iaid == iaid) {
323 new_iaid = 0;
324 break;
325 }
326 }
327
328 if (!new_iaid)
329 continue;
330
331 // construct header
332 struct dhcpv6_ia_hdr hdr_ia_pd = {
333 htons(DHCPV6_OPT_IA_PD),
334 htons(sizeof(hdr_ia_pd) - 4),
335 iaid, 0, 0
336 };
337
338 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
339 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
340 ia_pd_len += sizeof(hdr_ia_pd);
341
342 for (size_t j = i; j < ia_pd_entries; j++) {
343 if (e[j].iaid != iaid)
344 continue;
345
346 uint8_t ex_len = 0;
347 if (e[j].priority > 0)
348 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
349
350 struct dhcpv6_ia_prefix p = {
351 .type = htons(DHCPV6_OPT_IA_PREFIX),
352 .len = htons(sizeof(p) - 4U + ex_len),
353 .prefix = e[j].length,
354 .addr = e[j].target
355 };
356
357 if (type == DHCPV6_MSG_REQUEST) {
358 p.preferred = htonl(e[j].preferred);
359 p.valid = htonl(e[j].valid);
360 }
361
362 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
363 ia_pd_len += sizeof(p);
364
365 if (ex_len) {
366 ia_pd[ia_pd_len++] = 0;
367 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
368 ia_pd[ia_pd_len++] = 0;
369 ia_pd[ia_pd_len++] = ex_len - 4;
370 ia_pd[ia_pd_len++] = e[j].priority;
371
372 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
373 excl >>= (64 - e[j].priority);
374 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
375
376 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
377 ia_pd[ia_pd_len + i] = excl & 0xff;
378 ia_pd_len += ex_len - 5;
379 }
380
381 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
382 }
383 }
384 }
385
386 if (ia_pd_entries > 0)
387 request_prefix = 1;
388
389 // Build IA_NAs
390 size_t ia_na_entries, ia_na_len = 0;
391 void *ia_na = NULL;
392 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
393 ia_na_entries /= sizeof(*e);
394
395 struct dhcpv6_ia_hdr hdr_ia_na = {
396 htons(DHCPV6_OPT_IA_NA),
397 htons(sizeof(hdr_ia_na) - 4),
398 htonl(1), 0, 0
399 };
400
401 struct dhcpv6_ia_addr pa[ia_na_entries];
402 for (size_t i = 0; i < ia_na_entries; ++i) {
403 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
404 pa[i].len = htons(sizeof(pa[i]) - 4U);
405 pa[i].addr = e[i].target;
406
407 if (type == DHCPV6_MSG_REQUEST) {
408 pa[i].preferred = htonl(e[i].preferred);
409 pa[i].valid = htonl(e[i].valid);
410 } else {
411 pa[i].preferred = 0;
412 pa[i].valid = 0;
413 }
414 }
415
416 ia_na = pa;
417 ia_na_len = sizeof(pa);
418 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
419
420 // Reconfigure Accept
421 struct {
422 uint16_t type;
423 uint16_t length;
424 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
425
426 // Request Information Refresh
427 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
428
429 // Build vendor-class option
430 size_t vendor_class_len, user_class_len;
431 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
432 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
433
434 struct {
435 uint16_t type;
436 uint16_t length;
437 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
438
439 struct {
440 uint16_t type;
441 uint16_t length;
442 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
443
444 // Prepare Header
445 size_t oro_len;
446 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
447 struct {
448 uint8_t type;
449 uint8_t trid[3];
450 uint16_t elapsed_type;
451 uint16_t elapsed_len;
452 uint16_t elapsed_value;
453 uint16_t oro_type;
454 uint16_t oro_len;
455 } hdr = {
456 type, {trid[0], trid[1], trid[2]},
457 htons(DHCPV6_OPT_ELAPSED), htons(2),
458 htons((ecs > 0xffff) ? 0xffff : ecs),
459 htons(DHCPV6_OPT_ORO), htons(oro_len),
460 };
461
462 struct iovec iov[IOV_TOTAL] = {
463 [IOV_HDR] = {&hdr, sizeof(hdr)},
464 [IOV_ORO] = {oro, oro_len},
465 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
466 [IOV_CL_ID] = {cl_id, cl_id_len},
467 [IOV_SRV_ID] = {srv_id, srv_id_len},
468 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
469 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
470 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
471 [IOV_USER_CLASS] = {user_class, user_class_len},
472 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
473 [IOV_FQDN] = {&fqdn, fqdn_len},
474 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
475 [IOV_IA_NA] = {ia_na, ia_na_len},
476 [IOV_IA_PD] = {ia_pd, ia_pd_len},
477 };
478
479 size_t cnt = IOV_TOTAL;
480 if (type == DHCPV6_MSG_INFO_REQ) {
481 cnt = 9;
482 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
483 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
484 } else if (!request_prefix)
485 cnt = 13;
486
487 // Disable IAs if not used
488 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
489 iov[IOV_HDR_IA_NA].iov_len = 0;
490
491 if (na_mode == IA_MODE_NONE)
492 iov[IOV_HDR_IA_NA].iov_len = 0;
493
494 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
495 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
496 iov[IOV_RECONF_ACCEPT].iov_len = 0;
497
498 if (!(client_options & DHCPV6_CLIENT_FQDN))
499 iov[IOV_FQDN].iov_len = 0;
500
501 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
502 0, ALL_DHCPV6_RELAYS, ifindex};
503 struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
504 .msg_iov = iov, .msg_iovlen = cnt};
505
506 switch (type) {
507 case DHCPV6_MSG_REQUEST:
508 case DHCPV6_MSG_RENEW:
509 case DHCPV6_MSG_RELEASE:
510 case DHCPV6_MSG_DECLINE:
511 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
512 odhcp6c_addr_in_scope(&server_addr)) {
513 srv.sin6_addr = server_addr;
514 if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
515 srv.sin6_scope_id = 0;
516 }
517 break;
518 default:
519 break;
520 }
521
522 if (sendmsg(sock, &msg, 0) < 0) {
523 char in6_str[INET6_ADDRSTRLEN];
524
525 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
526 inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
527 in6_str, sizeof(in6_str)), strerror(errno));
528 }
529 }
530
531 static int64_t dhcpv6_rand_delay(int64_t time)
532 {
533 int random;
534 odhcp6c_random(&random, sizeof(random));
535
536 return (time * ((int64_t)random % 1000LL)) / 10000LL;
537 }
538
539 int dhcpv6_request(enum dhcpv6_msg type)
540 {
541 uint8_t rc = 0;
542 uint64_t timeout = UINT32_MAX;
543 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
544
545 if (retx->delay) {
546 struct timespec ts = {0, 0};
547 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
548
549 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
550 }
551
552 if (type == DHCPV6_MSG_UNKNOWN)
553 timeout = t1;
554 else if (type == DHCPV6_MSG_RENEW)
555 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
556 else if (type == DHCPV6_MSG_REBIND)
557 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
558
559 if (timeout == 0)
560 return -1;
561
562 syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
563 retx->name, timeout, retx->max_rc);
564
565 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
566
567 // Generate transaction ID
568 uint8_t trid[3] = {0, 0, 0};
569 if (type != DHCPV6_MSG_UNKNOWN)
570 odhcp6c_random(trid, sizeof(trid));
571
572 ssize_t len = -1;
573 int64_t rto = 0;
574
575 do {
576 if (rto == 0) {
577 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
578
579 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
580 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
581 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
582
583 rto = (retx->init_timeo * 1000 + delay);
584 } else
585 rto = (2 * rto + dhcpv6_rand_delay(rto));
586
587 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
588 rto = retx->max_timeo * 1000 +
589 dhcpv6_rand_delay(retx->max_timeo * 1000);
590
591 // Calculate end for this round and elapsed time
592 uint64_t round_end = round_start + rto;
593 elapsed = round_start - start;
594
595 // Don't wait too long if timeout differs from infinite
596 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
597 round_end = timeout * 1000 + start;
598
599 // Built and send package
600 switch (type) {
601 case DHCPV6_MSG_UNKNOWN:
602 break;
603 default:
604 syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
605 retx->name, elapsed, rc);
606 // Fall through
607 case DHCPV6_MSG_SOLICIT:
608 case DHCPV6_MSG_INFO_REQ:
609 dhcpv6_send(type, trid, elapsed / 10);
610 rc++;
611 }
612
613 // Receive rounds
614 for (; len < 0 && (round_start < round_end);
615 round_start = odhcp6c_get_milli_time()) {
616 uint8_t buf[1536];
617 union {
618 struct cmsghdr hdr;
619 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
620 } cmsg_buf;
621 struct iovec iov = {buf, sizeof(buf)};
622 struct sockaddr_in6 addr;
623 struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
624 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
625 .msg_controllen = sizeof(cmsg_buf)};
626 struct in6_pktinfo *pktinfo = NULL;
627
628 // Check for pending signal
629 if (odhcp6c_signal_process())
630 return -1;
631
632 // Set timeout for receiving
633 uint64_t t = round_end - round_start;
634 struct timeval tv = {t / 1000, (t % 1000) * 1000};
635 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
636 &tv, sizeof(tv));
637
638 // Receive cycle
639 len = recvmsg(sock, &msg, 0);
640 if (len < 0)
641 continue;
642
643 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
644 ch = CMSG_NXTHDR(&msg, ch)) {
645 if (ch->cmsg_level == SOL_IPV6 &&
646 ch->cmsg_type == IPV6_PKTINFO) {
647 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
648 break;
649 }
650 }
651
652 if (pktinfo == NULL) {
653 len = -1;
654 continue;
655 }
656
657 if (!dhcpv6_response_is_valid(buf, len, trid,
658 type, &pktinfo->ipi6_addr)) {
659 len = -1;
660 continue;
661 }
662
663 uint8_t *opt = &buf[4];
664 uint8_t *opt_end = opt + len - 4;
665
666 round_start = odhcp6c_get_milli_time();
667 elapsed = round_start - start;
668 syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
669 elapsed);
670
671 if (retx->handler_reply)
672 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
673
674 if (len > 0 && round_end - round_start > 1000)
675 round_end = 1000 + round_start;
676 }
677
678 // Allow
679 if (retx->handler_finish)
680 len = retx->handler_finish();
681 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
682 (!retx->max_rc || rc < retx->max_rc));
683 return len;
684 }
685
686 // Message validation checks according to RFC3315 chapter 15
687 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
688 const uint8_t transaction[3], enum dhcpv6_msg type,
689 const struct in6_addr *daddr)
690 {
691 const struct dhcpv6_header *rep = buf;
692 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
693 transaction, sizeof(rep->tr_id)))
694 return false; // Invalid reply
695
696 if (type == DHCPV6_MSG_SOLICIT) {
697 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
698 rep->msg_type != DHCPV6_MSG_REPLY)
699 return false;
700
701 } else if (type == DHCPV6_MSG_UNKNOWN) {
702 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
703 return false;
704
705 } else if (rep->msg_type != DHCPV6_MSG_REPLY)
706 return false;
707
708 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
709 rcmsg = DHCPV6_MSG_UNKNOWN;
710 uint16_t otype, olen = UINT16_MAX;
711 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
712 ia_present = false, options_valid = true;
713
714 size_t client_id_len, server_id_len;
715 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
716 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
717
718 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
719 if (otype == DHCPV6_OPT_CLIENTID) {
720 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
721 &odata[-4], client_id, client_id_len);
722 } else if (otype == DHCPV6_OPT_SERVERID) {
723 if (server_id_len)
724 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
725 &odata[-4], server_id, server_id_len);
726 else
727 serverid_ok = true;
728 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
729 sizeof(struct dhcpv6_auth_reconfigure)) {
730 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
731 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
732 continue;
733
734 md5_ctx_t md5;
735 uint8_t serverhash[16], secretbytes[64];
736 uint32_t hash[4];
737 memcpy(serverhash, r->key, sizeof(serverhash));
738 memset(r->key, 0, sizeof(r->key));
739
740 memset(secretbytes, 0, sizeof(secretbytes));
741 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
742
743 for (size_t i = 0; i < sizeof(secretbytes); ++i)
744 secretbytes[i] ^= 0x36;
745
746 md5_begin(&md5);
747 md5_hash(secretbytes, sizeof(secretbytes), &md5);
748 md5_hash(buf, len, &md5);
749 md5_end(hash, &md5);
750
751 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
752 secretbytes[i] ^= 0x36;
753 secretbytes[i] ^= 0x5c;
754 }
755
756 md5_begin(&md5);
757 md5_hash(secretbytes, sizeof(secretbytes), &md5);
758 md5_hash(hash, 16, &md5);
759 md5_end(hash, &md5);
760
761 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
762 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
763 rcmsg = odata[0];
764 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
765 ia_present = true;
766 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
767 options_valid = false;
768 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
769 (otype == DHCPV6_OPT_PD_EXCLUDE))
770 // Options are not allowed on global level
771 options_valid = false;
772 }
773
774 if (!options_valid || ((odata + olen) > end))
775 return false;
776
777 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
778 return false;
779
780 if (rep->msg_type == DHCPV6_MSG_RECONF) {
781 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
782 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
783 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
784 return false;
785 }
786
787 return clientid_ok && serverid_ok;
788 }
789
790 int dhcpv6_poll_reconfigure(void)
791 {
792 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
793
794 if (ret != -1)
795 ret = dhcpv6_request(ret);
796
797 return ret;
798 }
799
800 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
801 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
802 {
803 uint16_t otype, olen;
804 uint8_t *odata;
805 int msg = -1;
806
807 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
808 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
809 odata[0] == DHCPV6_MSG_RENEW ||
810 odata[0] == DHCPV6_MSG_INFO_REQ))
811 msg = odata[0];
812 }
813
814 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
815
816 return msg;
817 }
818
819 // Collect all advertised servers
820 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
821 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
822 {
823 uint16_t olen, otype;
824 uint8_t *odata, pref = 0;
825 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
826 IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
827 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
828 bool have_na = false;
829 int have_pd = 0;
830
831 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
832 if (orig == DHCPV6_MSG_SOLICIT &&
833 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
834 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
835 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
836 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
837 }
838
839 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
840 memcpy(cand.duid, odata, olen);
841 cand.duid_len = olen;
842 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
843 cand.preference >= 0) {
844 cand.preference = pref = odata[0];
845 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
846 cand.server_addr = *(struct in6_addr *)odata;
847 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
848 cand.wants_reconfigure = true;
849 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
850 uint32_t sol_max_rt = ntohl_unaligned(odata);
851 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
852 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
853 cand.sol_max_rt = sol_max_rt;
854
855 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
856 uint32_t inf_max_rt = ntohl_unaligned(odata);
857 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
858 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
859 cand.inf_max_rt = inf_max_rt;
860
861 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
862 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
863 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
864 uint8_t *oend = odata + olen, *d;
865 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
866 if (otype == DHCPV6_OPT_IA_PREFIX &&
867 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
868 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
869 have_pd = p->prefix;
870 }
871 }
872 } else if (otype == DHCPV6_OPT_IA_NA &&
873 olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
874 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
875 uint8_t *oend = odata + olen, *d;
876
877 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
878 if (otype == DHCPV6_OPT_IA_ADDR &&
879 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
880 have_na = true;
881 }
882 }
883 }
884
885 if ((!have_na && na_mode == IA_MODE_FORCE) ||
886 (!have_pd && pd_mode == IA_MODE_FORCE)) {
887 /*
888 * RFC7083 states to process the SOL_MAX_RT and
889 * INF_MAX_RT options even if the DHCPv6 server
890 * did not propose any IA_NA and/or IA_PD
891 */
892 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
893 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
894 return -1;
895 }
896
897 if (na_mode != IA_MODE_NONE && !have_na) {
898 cand.has_noaddravail = true;
899 cand.preference -= 1000;
900 }
901
902 if (pd_mode != IA_MODE_NONE) {
903 if (have_pd)
904 cand.preference += 2000 + (128 - have_pd);
905 else
906 cand.preference -= 2000;
907 }
908
909 if (cand.duid_len > 0) {
910 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
911 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
912 dhcpv6_add_server_cand(&cand);
913 }
914
915 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
916 }
917
918 static int dhcpv6_commit_advert(void)
919 {
920 return dhcpv6_promote_server_cand();
921 }
922
923 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
924 const void *opt, const void *end, const struct sockaddr_in6 *from)
925 {
926 dhcpv6_handle_advert(orig, rc, opt, end, from);
927 if (dhcpv6_commit_advert() < 0)
928 return -1;
929
930 return dhcpv6_handle_reply(orig, rc, opt, end, from);
931 }
932
933 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
934 const void *opt, const void *end, const struct sockaddr_in6 *from)
935 {
936 uint8_t *odata;
937 uint16_t otype, olen;
938 uint32_t refresh = 86400;
939 int ret = 1;
940 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
941
942 odhcp6c_expire();
943
944 if (orig == DHCPV6_MSG_UNKNOWN) {
945 static time_t last_update = 0;
946 time_t now = odhcp6c_get_milli_time() / 1000;
947
948 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
949 last_update = now;
950
951 if (t1 != UINT32_MAX)
952 t1 -= elapsed;
953
954 if (t2 != UINT32_MAX)
955 t2 -= elapsed;
956
957 if (t3 != UINT32_MAX)
958 t3 -= elapsed;
959
960 if (t1 < 0)
961 t1 = 0;
962
963 if (t2 < 0)
964 t2 = 0;
965
966 if (t3 < 0)
967 t3 = 0;
968 }
969
970 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
971 // Delete NA and PD we have in the state from the Advert
972 odhcp6c_clear_state(STATE_IA_NA);
973 odhcp6c_clear_state(STATE_IA_PD);
974 }
975
976 if (opt) {
977 odhcp6c_clear_state(STATE_DNS);
978 odhcp6c_clear_state(STATE_SEARCH);
979 odhcp6c_clear_state(STATE_SNTP_IP);
980 odhcp6c_clear_state(STATE_NTP_IP);
981 odhcp6c_clear_state(STATE_NTP_FQDN);
982 odhcp6c_clear_state(STATE_SIP_IP);
983 odhcp6c_clear_state(STATE_SIP_FQDN);
984 odhcp6c_clear_state(STATE_AFTR_NAME);
985 odhcp6c_clear_state(STATE_CER);
986 odhcp6c_clear_state(STATE_S46_MAPT);
987 odhcp6c_clear_state(STATE_S46_MAPE);
988 odhcp6c_clear_state(STATE_S46_LW);
989 odhcp6c_clear_state(STATE_PASSTHRU);
990 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
991
992 // Parse and find all matching IAs
993 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
994 bool passthru = true;
995
996 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
997 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
998 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
999
1000 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1001 (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1002 continue;
1003
1004 // Test ID
1005 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1006 continue;
1007
1008 uint16_t code = DHCPV6_Success;
1009 uint16_t stype, slen;
1010 uint8_t *sdata;
1011 // Get and handle status code
1012 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1013 stype, slen, sdata) {
1014 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1015 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1016 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1017
1018 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1019
1020 if (code == DHCPV6_Success)
1021 continue;
1022
1023 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1024 code, mdata, mlen, handled_status_codes, &ret);
1025
1026 if (ret > 0)
1027 return ret;
1028
1029 break;
1030 }
1031 }
1032
1033 if (code != DHCPV6_Success)
1034 continue;
1035
1036 dhcpv6_parse_ia(ia_hdr, odata + olen);
1037 passthru = false;
1038 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1039 server_addr = *(struct in6_addr *)odata;
1040 passthru = false;
1041 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1042 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1043 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1044 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1045
1046 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1047 passthru = false;
1048 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1049 if (olen % 16 == 0)
1050 odhcp6c_add_state(STATE_DNS, odata, olen);
1051 } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1052 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1053 else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1054 if (olen % 16 == 0)
1055 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1056 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1057 uint16_t stype, slen;
1058 uint8_t *sdata;
1059 // Test status and bail if error
1060 dhcpv6_for_each_option(odata, odata + olen,
1061 stype, slen, sdata) {
1062 if (slen == 16 && (stype == NTP_MC_ADDR ||
1063 stype == NTP_SRV_ADDR))
1064 odhcp6c_add_state(STATE_NTP_IP,
1065 sdata, slen);
1066 else if (slen > 0 && stype == NTP_SRV_FQDN)
1067 odhcp6c_add_state(STATE_NTP_FQDN,
1068 sdata, slen);
1069 }
1070 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1071 if (olen == 16)
1072 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1073 } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1074 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1075 else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1076 refresh = ntohl_unaligned(odata);
1077 passthru = false;
1078 } else if (otype == DHCPV6_OPT_AUTH) {
1079 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1080 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1081 if (r->protocol == 3 && r->algorithm == 1 &&
1082 r->reconf_type == 1)
1083 memcpy(reconf_key, r->key, sizeof(r->key));
1084 }
1085 passthru = false;
1086 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1087 size_t cur_len;
1088 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1089 if (cur_len == 0)
1090 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1091 passthru = false;
1092 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1093 uint32_t sol_max_rt = ntohl_unaligned(odata);
1094 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1095 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1096 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1097 passthru = false;
1098 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1099 uint32_t inf_max_rt = ntohl_unaligned(odata);
1100 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1101 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1102 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1103 passthru = false;
1104 #ifdef EXT_CER_ID
1105 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1106 sizeof(struct dhcpv6_cer_id)) {
1107 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1108 struct in6_addr any = IN6ADDR_ANY_INIT;
1109 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1110 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1111 passthru = false;
1112 #endif
1113 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1114 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1115 passthru = false;
1116 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1117 size_t mape_len;
1118 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1119 if (mape_len == 0)
1120 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1121 passthru = false;
1122 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1123 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1124 passthru = false;
1125 } else if (otype == DHCPV6_OPT_CLIENTID ||
1126 otype == DHCPV6_OPT_SERVERID ||
1127 otype == DHCPV6_OPT_IA_TA ||
1128 otype == DHCPV6_OPT_PREF ||
1129 otype == DHCPV6_OPT_UNICAST ||
1130 otype == DHCPV6_OPT_FQDN ||
1131 otype == DHCPV6_OPT_RECONF_ACCEPT)
1132 passthru = false;
1133 else
1134 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1135
1136 if (passthru)
1137 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1138 }
1139 }
1140
1141 switch (orig) {
1142 case DHCPV6_MSG_REQUEST:
1143 case DHCPV6_MSG_REBIND:
1144 case DHCPV6_MSG_RENEW:
1145 // Update refresh timers if no fatal status code was received
1146 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1147 if (orig == DHCPV6_MSG_REQUEST) {
1148 // All server candidates can be cleared if not yet bound
1149 if (!odhcp6c_is_bound())
1150 dhcpv6_clear_all_server_cand();
1151
1152 odhcp6c_clear_state(STATE_SERVER_ADDR);
1153 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1154 } else if (orig == DHCPV6_MSG_RENEW) {
1155 // Send further renews if T1 is not set
1156 if (!t1)
1157 ret = -1;
1158
1159 } else if (orig == DHCPV6_MSG_REBIND) {
1160 // Send further rebinds if T1 and T2 is not set
1161 if (!t1 && !t2)
1162 ret = -1;
1163
1164 odhcp6c_clear_state(STATE_SERVER_ADDR);
1165 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1166 }
1167 }
1168 break;
1169
1170 case DHCPV6_MSG_INFO_REQ:
1171 if (ret > 0) {
1172 // All server candidates can be cleared if not yet bound
1173 if (!odhcp6c_is_bound())
1174 dhcpv6_clear_all_server_cand();
1175
1176 t1 = refresh;
1177 }
1178 break;
1179
1180 default:
1181 break;
1182 }
1183
1184 return ret;
1185 }
1186
1187 static int dhcpv6_parse_ia(void *opt, void *end)
1188 {
1189 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1190 int parsed_ia = 0;
1191 uint32_t t1, t2;
1192 uint16_t otype, olen;
1193 uint8_t *odata;
1194
1195 t1 = ntohl(ia_hdr->t1);
1196 t2 = ntohl(ia_hdr->t2);
1197
1198 if (t1 > t2)
1199 return 0;
1200
1201 // Update address IA
1202 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1203 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1204 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1205
1206 entry.iaid = ia_hdr->iaid;
1207
1208 if (otype == DHCPV6_OPT_IA_PREFIX) {
1209 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1210 if (olen + 4U < sizeof(*prefix))
1211 continue;
1212
1213 entry.valid = ntohl(prefix->valid);
1214 entry.preferred = ntohl(prefix->preferred);
1215
1216 if (entry.preferred > entry.valid)
1217 continue;
1218
1219 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1220 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1221 if (entry.t1 > entry.t2)
1222 entry.t1 = entry.t2;
1223
1224 entry.length = prefix->prefix;
1225 entry.target = prefix->addr;
1226 uint16_t stype, slen;
1227 uint8_t *sdata;
1228
1229 // Parse PD-exclude
1230 bool ok = true;
1231 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1232 odata + olen, stype, slen, sdata) {
1233 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1234 continue;
1235
1236 uint8_t elen = sdata[0];
1237 if (elen > 64)
1238 elen = 64;
1239
1240 if (entry.length < 32 || elen <= entry.length) {
1241 ok = false;
1242 continue;
1243 }
1244
1245 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1246 if (slen <= bytes) {
1247 ok = false;
1248 continue;
1249 }
1250
1251 uint32_t exclude = 0;
1252 do {
1253 exclude = exclude << 8 | sdata[bytes];
1254 } while (--bytes);
1255
1256 exclude >>= 8 - ((elen - entry.length) % 8);
1257 exclude <<= 64 - elen;
1258
1259 // Abusing router & priority fields for exclusion
1260 entry.router = entry.target;
1261 entry.router.s6_addr32[1] |= htonl(exclude);
1262 entry.priority = elen;
1263 }
1264
1265 if (ok) {
1266 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1267 parsed_ia++;
1268 }
1269
1270 entry.priority = 0;
1271 memset(&entry.router, 0, sizeof(entry.router));
1272 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1273 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1274 if (olen + 4U < sizeof(*addr))
1275 continue;
1276
1277 entry.preferred = ntohl(addr->preferred);
1278 entry.valid = ntohl(addr->valid);
1279
1280 if (entry.preferred > entry.valid)
1281 continue;
1282
1283 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1284 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1285 if (entry.t1 > entry.t2)
1286 entry.t1 = entry.t2;
1287
1288 entry.length = 128;
1289 entry.target = addr->addr;
1290
1291 odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1292 parsed_ia++;
1293 }
1294 }
1295 return parsed_ia;
1296 }
1297
1298 static int dhcpv6_calc_refresh_timers(void)
1299 {
1300 struct odhcp6c_entry *e;
1301 size_t ia_na_entries, ia_pd_entries, i;
1302 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1303
1304 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1305 ia_na_entries /= sizeof(*e);
1306
1307 for (i = 0; i < ia_na_entries; i++) {
1308 if (e[i].t1 < l_t1)
1309 l_t1 = e[i].t1;
1310
1311 if (e[i].t2 < l_t2)
1312 l_t2 = e[i].t2;
1313
1314 if (e[i].valid > l_t3)
1315 l_t3 = e[i].valid;
1316 }
1317
1318 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1319 ia_pd_entries /= sizeof(*e);
1320
1321 for (i = 0; i < ia_pd_entries; i++) {
1322 if (e[i].t1 < l_t1)
1323 l_t1 = e[i].t1;
1324
1325 if (e[i].t2 < l_t2)
1326 l_t2 = e[i].t2;
1327
1328 if (e[i].valid > l_t3)
1329 l_t3 = e[i].valid;
1330 }
1331
1332 if (ia_pd_entries || ia_na_entries) {
1333 t1 = l_t1;
1334 t2 = l_t2;
1335 t3 = l_t3;
1336 }
1337
1338 return (int)(ia_pd_entries + ia_na_entries);
1339 }
1340
1341 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1342 const void *status_msg, int len)
1343 {
1344 const char *src = status_msg;
1345 char buf[len + 3];
1346 char *dst = buf;
1347
1348 if (len) {
1349 *dst++ = '(';
1350 while (len--) {
1351 *dst = isprint((unsigned char)*src) ? *src : '?';
1352 src++;
1353 dst++;
1354 }
1355 *dst++ = ')';
1356 }
1357
1358 *dst = 0;
1359
1360 syslog(LOG_WARNING, "Server returned %s status %i %s",
1361 scope, code, buf);
1362 }
1363
1364 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1365 const uint16_t code, const void *status_msg, const int len,
1366 int *ret)
1367 {
1368 dhcpv6_log_status_code(code, "message", status_msg, len);
1369
1370 switch (code) {
1371 case DHCPV6_UnspecFail:
1372 // Generic failure
1373 *ret = 0;
1374 break;
1375
1376 case DHCPV6_UseMulticast:
1377 switch(orig) {
1378 case DHCPV6_MSG_REQUEST:
1379 case DHCPV6_MSG_RENEW:
1380 case DHCPV6_MSG_RELEASE:
1381 case DHCPV6_MSG_DECLINE:
1382 // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1383 server_addr = in6addr_any;
1384 *ret = 0;
1385 break;
1386 default:
1387 break;
1388 }
1389 break;
1390
1391 case DHCPV6_NoAddrsAvail:
1392 case DHCPV6_NoPrefixAvail:
1393 if (orig == DHCPV6_MSG_REQUEST)
1394 *ret = 0; // Failure
1395 break;
1396
1397 default:
1398 break;
1399 }
1400 }
1401
1402 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1403 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1404 const void *status_msg, const int len,
1405 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1406 {
1407 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1408 "IA_NA" : "IA_PD", status_msg, len);
1409
1410 switch (code) {
1411 case DHCPV6_NoBinding:
1412 switch (orig) {
1413 case DHCPV6_MSG_RENEW:
1414 case DHCPV6_MSG_REBIND:
1415 if ((*ret > 0) && !handled_status_codes[code])
1416 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1417 break;
1418
1419 default:
1420 break;
1421 }
1422 break;
1423
1424 default:
1425 *ret = 0;
1426 break;
1427 }
1428 }
1429
1430 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1431 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1432 {
1433 size_t cand_len, i;
1434 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1435
1436 // Remove identical duid server candidate
1437 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1438 if (cand->duid_len == c[i].duid_len &&
1439 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1440 free(c[i].ia_na);
1441 free(c[i].ia_pd);
1442 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1443 break;
1444 }
1445 }
1446
1447 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1448 i < cand_len / sizeof(*c); ++i) {
1449 if (c[i].preference < cand->preference)
1450 break;
1451 }
1452
1453 if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1454 free(cand->ia_na);
1455 free(cand->ia_pd);
1456 }
1457 }
1458
1459 static void dhcpv6_clear_all_server_cand(void)
1460 {
1461 size_t cand_len, i;
1462 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1463
1464 // Server candidates need deep delete for IA_NA/IA_PD
1465 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1466 free(c[i].ia_na);
1467 free(c[i].ia_pd);
1468 }
1469 odhcp6c_clear_state(STATE_SERVER_CAND);
1470 }
1471
1472 int dhcpv6_promote_server_cand(void)
1473 {
1474 size_t cand_len;
1475 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1476 uint16_t hdr[2];
1477 int ret = DHCPV6_STATELESS;
1478
1479 // Clear lingering candidate state info
1480 odhcp6c_clear_state(STATE_SERVER_ID);
1481 odhcp6c_clear_state(STATE_IA_NA);
1482 odhcp6c_clear_state(STATE_IA_PD);
1483
1484 if (!cand_len)
1485 return -1;
1486
1487 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1488 na_mode = IA_MODE_NONE;
1489
1490 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1491 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1492
1493 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1494 }
1495
1496 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1497 hdr[1] = htons(cand->duid_len);
1498 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1499 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1500 accept_reconfig = cand->wants_reconfigure;
1501
1502 if (cand->ia_na_len) {
1503 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1504 free(cand->ia_na);
1505 if (na_mode != IA_MODE_NONE)
1506 ret = DHCPV6_STATEFUL;
1507 }
1508
1509 if (cand->ia_pd_len) {
1510 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1511 free(cand->ia_pd);
1512 if (request_prefix)
1513 ret = DHCPV6_STATEFUL;
1514 }
1515
1516 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1517 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1518
1519 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1520
1521 return ret;
1522 }
Openwrt DHCPv6 Client