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