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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 <sys/time.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30
31 #include <net/if.h>
32 #include <net/ethernet.h>
33
34 #include "odhcp6c.h"
35 #include "md5.h"
36
37
38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
39 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
40 #define DHCPV6_CLIENT_PORT 546
41 #define DHCPV6_SERVER_PORT 547
42 #define DHCPV6_DUID_LLADDR 3
43 #define DHCPV6_REQ_DELAY 1
44
45 #define DHCPV6_SOL_MAX_RT_MIN 60
46 #define DHCPV6_SOL_MAX_RT_MAX 86400
47 #define DHCPV6_INF_MAX_RT_MIN 60
48 #define DHCPV6_INF_MAX_RT_MAX 86400
49
50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
51 const uint8_t transaction[3], enum dhcpv6_msg type,
52 const struct in6_addr *daddr);
53
54 static int dhcpv6_parse_ia(void *opt, void *end);
55
56 static int dhcpv6_calc_refresh_timers(void);
57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
58 const uint16_t code, const void *status_msg, const int len,
59 int *ret);
60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
61 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
62 const void *status_msg, const int len,
63 bool handled_status_codes[_DHCPV6_Status_Max],
64 int *ret);
65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
66 static void dhcpv6_clear_all_server_cand(void);
67
68 static reply_handler dhcpv6_handle_reply;
69 static reply_handler dhcpv6_handle_advert;
70 static reply_handler dhcpv6_handle_rebind_reply;
71 static reply_handler dhcpv6_handle_reconfigure;
72 static int dhcpv6_commit_advert(void);
73
74
75
76 // RFC 3315 - 5.5 Timeout and Delay values
77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
78 [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
79 dhcpv6_handle_reconfigure, NULL},
80 [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
81 dhcpv6_handle_advert, dhcpv6_commit_advert},
82 [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
83 dhcpv6_handle_reply, NULL},
84 [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
85 dhcpv6_handle_reply, NULL},
86 [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
87 dhcpv6_handle_rebind_reply, NULL},
88 [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
89 [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
90 [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
91 dhcpv6_handle_reply, NULL},
92 };
93
94
95 // Sockets
96 static int sock = -1;
97 static int ifindex = -1;
98 static int64_t t1 = 0, t2 = 0, t3 = 0;
99
100 // IA states
101 static int request_prefix = -1;
102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
103 static bool accept_reconfig = false;
104
105 // Reconfigure key
106 static uint8_t reconf_key[16];
107
108 // client options
109 static unsigned int client_options = 0;
110
111
112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
113 {
114 client_options = options;
115 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
116
117 sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
118 if (sock < 0)
119 return -1;
120
121 // Detect interface
122 struct ifreq ifr;
123 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
124 if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
125 return -1;
126 ifindex = ifr.ifr_ifindex;
127
128 // Create client DUID
129 size_t client_id_len;
130 odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
131 if (client_id_len == 0) {
132 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
133 DHCPV6_DUID_LLADDR, 0, 1};
134
135 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
136 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
137
138 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
139 struct ifreq ifs[100], *ifp, *ifend;
140 struct ifconf ifc;
141 ifc.ifc_req = ifs;
142 ifc.ifc_len = sizeof(ifs);
143
144 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
145 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
146 // If our interface doesn't have an address...
147 ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
148 for (ifp = ifc.ifc_req; ifp < ifend &&
149 !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
150 memcpy(ifr.ifr_name, ifp->ifr_name,
151 sizeof(ifr.ifr_name));
152 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
153 continue;
154
155 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
156 ETHER_ADDR_LEN);
157 }
158 }
159
160 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
161 }
162
163 // Create ORO
164 if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
165 uint16_t oro[] = {
166 htons(DHCPV6_OPT_SIP_SERVER_D),
167 htons(DHCPV6_OPT_SIP_SERVER_A),
168 htons(DHCPV6_OPT_DNS_SERVERS),
169 htons(DHCPV6_OPT_DNS_DOMAIN),
170 htons(DHCPV6_OPT_SNTP_SERVERS),
171 htons(DHCPV6_OPT_NTP_SERVER),
172 htons(DHCPV6_OPT_AFTR_NAME),
173 htons(DHCPV6_OPT_PD_EXCLUDE),
174 htons(DHCPV6_OPT_SOL_MAX_RT),
175 htons(DHCPV6_OPT_INF_MAX_RT),
176 #ifdef EXT_PREFIX_CLASS
177 htons(DHCPV6_OPT_PREFIX_CLASS),
178 #endif
179 #ifdef EXT_CER_ID
180 htons(DHCPV6_OPT_CER_ID),
181 #endif
182 htons(DHCPV6_OPT_S46_CONT_MAPE),
183 htons(DHCPV6_OPT_S46_CONT_MAPT),
184 htons(DHCPV6_OPT_S46_CONT_LW),
185 };
186 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
187 }
188
189 // Configure IPv6-options
190 int val = 1;
191 setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
192 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
193 setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
194 setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
195
196 struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
197 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
198 if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
199 return -1;
200
201 return 0;
202 }
203
204 enum {
205 IOV_HDR=0,
206 IOV_ORO,
207 IOV_ORO_REFRESH,
208 IOV_CL_ID,
209 IOV_SRV_ID,
210 IOV_VENDOR_CLASS_HDR,
211 IOV_VENDOR_CLASS,
212 IOV_USER_CLASS_HDR,
213 IOV_USER_CLASS,
214 IOV_RECONF_ACCEPT,
215 IOV_FQDN,
216 IOV_HDR_IA_NA,
217 IOV_IA_NA,
218 IOV_IA_PD,
219 IOV_TOTAL
220 };
221
222 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
223 {
224 na_mode = na;
225 pd_mode = pd;
226 }
227
228 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
229 {
230 // Build FQDN
231 char fqdn_buf[256];
232 gethostname(fqdn_buf, sizeof(fqdn_buf));
233 struct {
234 uint16_t type;
235 uint16_t len;
236 uint8_t flags;
237 uint8_t data[256];
238 } fqdn;
239 size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
240 sizeof(fqdn.data), NULL, NULL);
241 fqdn.type = htons(DHCPV6_OPT_FQDN);
242 fqdn.len = htons(fqdn_len - 4);
243 fqdn.flags = 0;
244
245
246 // Build Client ID
247 size_t cl_id_len;
248 void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
249
250 // Get Server ID
251 size_t srv_id_len;
252 void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
253
254 // Build IA_PDs
255 size_t ia_pd_entries = 0, ia_pd_len = 0;
256 uint8_t *ia_pd;
257
258 if (type == DHCPV6_MSG_SOLICIT) {
259 odhcp6c_clear_state(STATE_IA_PD);
260 size_t n_prefixes;
261 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
262 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
263
264 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
265
266 for (size_t i = 0; i < n_prefixes; i++) {
267 struct dhcpv6_ia_hdr hdr_ia_pd = {
268 htons(DHCPV6_OPT_IA_PD),
269 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
270 request_prefixes[i].iaid, 0, 0
271 };
272 struct dhcpv6_ia_prefix pref = {
273 .type = htons(DHCPV6_OPT_IA_PREFIX),
274 .len = htons(25), .prefix = request_prefixes[i].length
275 };
276 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
277 ia_pd_len += sizeof(hdr_ia_pd);
278 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
279 ia_pd_len += sizeof(pref);
280 }
281 } else {
282 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
283 ia_pd_entries /= sizeof(*e);
284
285 // we're too lazy to count our distinct IAIDs,
286 // so just allocate maximally needed space
287 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
288 sizeof(struct dhcpv6_ia_hdr)));
289
290 for (size_t i = 0; i < ia_pd_entries; ++i) {
291 uint32_t iaid = e[i].iaid;
292
293 // check if this is an unprocessed IAID and skip if not.
294 int new_iaid = 1;
295 for (int j = i-1; j >= 0; j--) {
296 if (e[j].iaid == iaid) {
297 new_iaid = 0;
298 break;
299 }
300 }
301
302 if (!new_iaid)
303 continue;
304
305 // construct header
306 struct dhcpv6_ia_hdr hdr_ia_pd = {
307 htons(DHCPV6_OPT_IA_PD),
308 htons(sizeof(hdr_ia_pd) - 4),
309 iaid, 0, 0
310 };
311
312 memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
313 struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
314 ia_pd_len += sizeof(hdr_ia_pd);
315
316 for (size_t j = i; j < ia_pd_entries; j++) {
317 if (e[j].iaid != iaid)
318 continue;
319
320 uint8_t ex_len = 0;
321 if (e[j].priority > 0)
322 ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
323
324 struct dhcpv6_ia_prefix p = {
325 .type = htons(DHCPV6_OPT_IA_PREFIX),
326 .len = htons(sizeof(p) - 4U + ex_len),
327 .prefix = e[j].length,
328 .addr = e[j].target
329 };
330
331 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
332 ia_pd_len += sizeof(p);
333
334 if (ex_len) {
335 ia_pd[ia_pd_len++] = 0;
336 ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
337 ia_pd[ia_pd_len++] = 0;
338 ia_pd[ia_pd_len++] = ex_len - 4;
339 ia_pd[ia_pd_len++] = e[j].priority;
340
341 uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
342 excl >>= (64 - e[j].priority);
343 excl <<= 8 - ((e[j].priority - e[j].length) % 8);
344
345 for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
346 ia_pd[ia_pd_len + i] = excl & 0xff;
347 ia_pd_len += ex_len - 5;
348 }
349
350 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
351 }
352 }
353 }
354
355 if (ia_pd_entries > 0)
356 request_prefix = 1;
357
358 // Build IA_NAs
359 size_t ia_na_entries, ia_na_len = 0;
360 void *ia_na = NULL;
361 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
362 ia_na_entries /= sizeof(*e);
363
364 struct dhcpv6_ia_hdr hdr_ia_na = {
365 htons(DHCPV6_OPT_IA_NA),
366 htons(sizeof(hdr_ia_na) - 4),
367 htonl(1), 0, 0
368 };
369
370 struct dhcpv6_ia_addr pa[ia_na_entries];
371 for (size_t i = 0; i < ia_na_entries; ++i) {
372 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
373 pa[i].len = htons(sizeof(pa[i]) - 4U);
374 pa[i].addr = e[i].target;
375 pa[i].preferred = 0;
376 pa[i].valid = 0;
377 }
378
379 ia_na = pa;
380 ia_na_len = sizeof(pa);
381 hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
382
383 // Reconfigure Accept
384 struct {
385 uint16_t type;
386 uint16_t length;
387 } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
388
389 // Request Information Refresh
390 uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
391
392 // Build vendor-class option
393 size_t vendor_class_len, user_class_len;
394 struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
395 void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
396
397 struct {
398 uint16_t type;
399 uint16_t length;
400 } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
401
402 struct {
403 uint16_t type;
404 uint16_t length;
405 } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
406
407 // Prepare Header
408 size_t oro_len;
409 void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
410 struct {
411 uint8_t type;
412 uint8_t trid[3];
413 uint16_t elapsed_type;
414 uint16_t elapsed_len;
415 uint16_t elapsed_value;
416 uint16_t oro_type;
417 uint16_t oro_len;
418 } hdr = {
419 type, {trid[0], trid[1], trid[2]},
420 htons(DHCPV6_OPT_ELAPSED), htons(2),
421 htons((ecs > 0xffff) ? 0xffff : ecs),
422 htons(DHCPV6_OPT_ORO), htons(oro_len),
423 };
424
425 struct iovec iov[IOV_TOTAL] = {
426 [IOV_HDR] = {&hdr, sizeof(hdr)},
427 [IOV_ORO] = {oro, oro_len},
428 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
429 [IOV_CL_ID] = {cl_id, cl_id_len},
430 [IOV_SRV_ID] = {srv_id, srv_id_len},
431 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
432 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
433 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
434 [IOV_USER_CLASS] = {user_class, user_class_len},
435 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
436 [IOV_FQDN] = {&fqdn, fqdn_len},
437 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
438 [IOV_IA_NA] = {ia_na, ia_na_len},
439 [IOV_IA_PD] = {ia_pd, ia_pd_len},
440 };
441
442 size_t cnt = IOV_TOTAL;
443 if (type == DHCPV6_MSG_INFO_REQ) {
444 cnt = 9;
445 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
446 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
447 } else if (!request_prefix) {
448 cnt = 13;
449 }
450
451 // Disable IAs if not used
452 if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
453 iov[IOV_HDR_IA_NA].iov_len = 0;
454
455 if (na_mode == IA_MODE_NONE)
456 iov[IOV_HDR_IA_NA].iov_len = 0;
457
458 if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
459 !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
460 iov[IOV_RECONF_ACCEPT].iov_len = 0;
461
462 if (!(client_options & DHCPV6_CLIENT_FQDN))
463 iov[IOV_FQDN].iov_len = 0;
464
465 struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
466 0, ALL_DHCPV6_RELAYS, ifindex};
467 struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
468
469 sendmsg(sock, &msg, 0);
470 }
471
472
473 static int64_t dhcpv6_rand_delay(int64_t time)
474 {
475 int random;
476 odhcp6c_random(&random, sizeof(random));
477 return (time * ((int64_t)random % 1000LL)) / 10000LL;
478 }
479
480
481 int dhcpv6_request(enum dhcpv6_msg type)
482 {
483 uint8_t rc = 0;
484 uint64_t timeout = UINT32_MAX;
485 struct dhcpv6_retx *retx = &dhcpv6_retx[type];
486
487 if (retx->delay) {
488 struct timespec ts = {0, 0};
489 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
490 nanosleep(&ts, NULL);
491 }
492
493 if (type == DHCPV6_MSG_UNKNOWN)
494 timeout = t1;
495 else if (type == DHCPV6_MSG_RENEW)
496 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
497 else if (type == DHCPV6_MSG_REBIND)
498 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
499
500 if (timeout == 0)
501 return -1;
502
503 syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
504 retx->name, (unsigned long long)timeout, retx->max_rc);
505
506 uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
507
508 // Generate transaction ID
509 uint8_t trid[3] = {0, 0, 0};
510 if (type != DHCPV6_MSG_UNKNOWN)
511 odhcp6c_random(trid, sizeof(trid));
512 ssize_t len = -1;
513 int64_t rto = 0;
514
515 do {
516 if (rto == 0) {
517 int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
518
519 // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
520 while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
521 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
522
523 rto = (retx->init_timeo * 1000 + delay);
524 }
525 else
526 rto = (2 * rto + dhcpv6_rand_delay(rto));
527
528 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
529 rto = retx->max_timeo * 1000 +
530 dhcpv6_rand_delay(retx->max_timeo * 1000);
531
532 // Calculate end for this round and elapsed time
533 uint64_t round_end = round_start + rto;
534 elapsed = round_start - start;
535
536 // Don't wait too long if timeout differs from infinite
537 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
538 round_end = timeout * 1000 + start;
539
540 // Built and send package
541 if (type != DHCPV6_MSG_UNKNOWN) {
542 if (type != DHCPV6_MSG_SOLICIT)
543 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
544 retx->name, (unsigned long long)elapsed, rc);
545 dhcpv6_send(type, trid, elapsed / 10);
546 rc++;
547 }
548
549 // Receive rounds
550 for (; len < 0 && (round_start < round_end);
551 round_start = odhcp6c_get_milli_time()) {
552 uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
553 struct iovec iov = {buf, sizeof(buf)};
554 struct sockaddr_in6 addr;
555 struct msghdr msg = {&addr, sizeof(addr), &iov, 1,
556 cmsg_buf, sizeof(cmsg_buf), 0};
557 struct in6_pktinfo *pktinfo = NULL;
558
559
560 // Check for pending signal
561 if (odhcp6c_signal_process())
562 return -1;
563
564 // Set timeout for receiving
565 uint64_t t = round_end - round_start;
566 struct timeval tv = {t / 1000, (t % 1000) * 1000};
567 setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
568 &tv, sizeof(tv));
569
570 // Receive cycle
571 len = recvmsg(sock, &msg, 0);
572 if (len < 0)
573 continue;
574
575 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
576 ch = CMSG_NXTHDR(&msg, ch)) {
577 if (ch->cmsg_level == SOL_IPV6 &&
578 ch->cmsg_type == IPV6_PKTINFO) {
579 pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
580 break;
581 }
582 }
583
584 if (pktinfo == NULL) {
585 len = -1;
586 continue;
587 }
588
589 if (!dhcpv6_response_is_valid(buf, len, trid,
590 type, &pktinfo->ipi6_addr)) {
591 len = -1;
592 continue;
593 }
594
595 uint8_t *opt = &buf[4];
596 uint8_t *opt_end = opt + len - 4;
597
598 round_start = odhcp6c_get_milli_time();
599 elapsed = round_start - start;
600 syslog(LOG_NOTICE, "Got a valid reply after "
601 "%llums", (unsigned long long)elapsed);
602
603 if (retx->handler_reply)
604 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
605
606 if (len > 0 && round_end - round_start > 1000)
607 round_end = 1000 + round_start;
608 }
609
610 // Allow
611 if (retx->handler_finish)
612 len = retx->handler_finish();
613 } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
614 (!retx->max_rc || rc < retx->max_rc));
615 return len;
616 }
617
618 // Message validation checks according to RFC3315 chapter 15
619 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
620 const uint8_t transaction[3], enum dhcpv6_msg type,
621 const struct in6_addr *daddr)
622 {
623 const struct dhcpv6_header *rep = buf;
624 if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
625 transaction, sizeof(rep->tr_id)))
626 return false; // Invalid reply
627
628 if (type == DHCPV6_MSG_SOLICIT) {
629 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
630 rep->msg_type != DHCPV6_MSG_REPLY)
631 return false;
632 } else if (type == DHCPV6_MSG_UNKNOWN) {
633 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
634 return false;
635 } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
636 return false;
637 }
638
639 uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
640 rcmsg = DHCPV6_MSG_UNKNOWN;
641 uint16_t otype, olen = UINT16_MAX;
642 bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
643 ia_present = false, options_valid = true;
644
645 size_t client_id_len, server_id_len;
646 void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
647 void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
648
649 dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
650 if (otype == DHCPV6_OPT_CLIENTID) {
651 clientid_ok = (olen + 4U == client_id_len) && !memcmp(
652 &odata[-4], client_id, client_id_len);
653 } else if (otype == DHCPV6_OPT_SERVERID) {
654 if (server_id_len)
655 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
656 &odata[-4], server_id, server_id_len);
657 else
658 serverid_ok = true;
659 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
660 sizeof(struct dhcpv6_auth_reconfigure)) {
661 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
662 if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
663 continue;
664
665 md5_ctx_t md5;
666 uint8_t serverhash[16], secretbytes[64], hash[16];
667 memcpy(serverhash, r->key, sizeof(serverhash));
668 memset(r->key, 0, sizeof(r->key));
669
670 memset(secretbytes, 0, sizeof(secretbytes));
671 memcpy(secretbytes, reconf_key, sizeof(reconf_key));
672
673 for (size_t i = 0; i < sizeof(secretbytes); ++i)
674 secretbytes[i] ^= 0x36;
675
676 md5_begin(&md5);
677 md5_hash(secretbytes, sizeof(secretbytes), &md5);
678 md5_hash(buf, len, &md5);
679 md5_end(hash, &md5);
680
681 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
682 secretbytes[i] ^= 0x36;
683 secretbytes[i] ^= 0x5c;
684 }
685
686 md5_begin(&md5);
687 md5_hash(secretbytes, sizeof(secretbytes), &md5);
688 md5_hash(hash, 16, &md5);
689 md5_end(hash, &md5);
690
691 rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
692 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
693 rcmsg = odata[0];
694 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
695 ia_present = true;
696 if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
697 options_valid = false;
698 }
699 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
700 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
701 // Options are not allowed on global level
702 options_valid = false;
703 }
704 }
705
706 if (!options_valid || ((odata + olen) > end))
707 return false;
708
709 if (type == DHCPV6_MSG_INFO_REQ && ia_present)
710 return false;
711
712 if (rep->msg_type == DHCPV6_MSG_RECONF) {
713 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
714 (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
715 !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
716 return false;
717 }
718
719 return clientid_ok && serverid_ok;
720 }
721
722
723 int dhcpv6_poll_reconfigure(void)
724 {
725 int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
726 if (ret != -1)
727 ret = dhcpv6_request(ret);
728
729 return ret;
730 }
731
732
733 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
734 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
735 {
736 uint16_t otype, olen;
737 uint8_t *odata, msg = DHCPV6_MSG_RENEW;
738 dhcpv6_for_each_option(opt, end, otype, olen, odata)
739 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
740 odata[0] == DHCPV6_MSG_RENEW ||
741 odata[0] == DHCPV6_MSG_INFO_REQ))
742 msg = odata[0];
743
744 dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
745 return msg;
746 }
747
748
749 // Collect all advertised servers
750 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
751 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
752 {
753 uint16_t olen, otype;
754 uint8_t *odata, pref = 0;
755 struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
756 DHCPV6_SOL_MAX_RT,
757 DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
758 bool have_na = false;
759 int have_pd = 0;
760
761 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
762 if (orig == DHCPV6_MSG_SOLICIT &&
763 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
764 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
765 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
766 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
767 }
768
769 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
770 memcpy(cand.duid, odata, olen);
771 cand.duid_len = olen;
772 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
773 int error = ((int)odata[0] << 8 | (int)odata[1]);
774
775 switch (error) {
776 case DHCPV6_NoPrefixAvail:
777 // Status code on global level
778 cand.preference -= 2000;
779 break;
780
781 default :
782 break;
783 }
784 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
785 cand.preference >= 0) {
786 cand.preference = pref = odata[0];
787 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
788 cand.wants_reconfigure = true;
789 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
790 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
791 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
792 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
793 cand.sol_max_rt = sol_max_rt;
794 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
795 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
796 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
797 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
798 cand.inf_max_rt = inf_max_rt;
799 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
800 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
801 uint8_t *oend = odata + olen, *d;
802 dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
803 if (otype == DHCPV6_OPT_IA_PREFIX &&
804 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
805 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
806 have_pd = p->prefix;
807 }
808 }
809 } else if (otype == DHCPV6_OPT_IA_NA) {
810 struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
811 uint8_t *oend = odata + olen, *d;
812 dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
813 if (otype == DHCPV6_OPT_IA_ADDR &&
814 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
815 have_na = true;
816 }
817 }
818
819 if ((!have_na && na_mode == IA_MODE_FORCE) ||
820 (!have_pd && pd_mode == IA_MODE_FORCE)) {
821 /*
822 * RFC7083 states to process the SOL_MAX_RT and
823 * INF_MAX_RT options even if the DHCPv6 server
824 * did not propose any IA_NA and/or IA_PD
825 */
826 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
827 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
828 return -1;
829 }
830
831 if (na_mode != IA_MODE_NONE && !have_na) {
832 cand.has_noaddravail = true;
833 cand.preference -= 1000;
834 }
835
836 if (pd_mode != IA_MODE_NONE) {
837 if (have_pd)
838 cand.preference += 2000 + (128 - have_pd);
839 else
840 cand.preference -= 2000;
841 }
842
843 if (cand.duid_len > 0) {
844 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
845 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
846 dhcpv6_add_server_cand(&cand);
847 }
848
849 return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
850 }
851
852
853 static int dhcpv6_commit_advert(void)
854 {
855 return dhcpv6_promote_server_cand();
856 }
857
858
859 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
860 const void *opt, const void *end, const struct sockaddr_in6 *from)
861 {
862 dhcpv6_handle_advert(orig, rc, opt, end, from);
863 if (dhcpv6_commit_advert() < 0)
864 return -1;
865
866 return dhcpv6_handle_reply(orig, rc, opt, end, from);
867 }
868
869
870 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
871 const void *opt, const void *end, const struct sockaddr_in6 *from)
872 {
873 uint8_t *odata;
874 uint16_t otype, olen;
875 uint32_t refresh = UINT32_MAX;
876 int ret = 1;
877 bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
878
879 odhcp6c_expire();
880
881 if (orig == DHCPV6_MSG_UNKNOWN) {
882 static time_t last_update = 0;
883 time_t now = odhcp6c_get_milli_time() / 1000;
884
885 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
886 last_update = now;
887
888 if (t1 != UINT32_MAX)
889 t1 -= elapsed;
890
891 if (t2 != UINT32_MAX)
892 t2 -= elapsed;
893
894 if (t3 != UINT32_MAX)
895 t3 -= elapsed;
896
897 if (t1 < 0)
898 t1 = 0;
899
900 if (t2 < 0)
901 t2 = 0;
902
903 if (t3 < 0)
904 t3 = 0;
905 }
906
907 if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
908 // Delete NA and PD we have in the state from the Advert
909 odhcp6c_clear_state(STATE_IA_NA);
910 odhcp6c_clear_state(STATE_IA_PD);
911 }
912
913 if (opt) {
914 odhcp6c_clear_state(STATE_DNS);
915 odhcp6c_clear_state(STATE_SEARCH);
916 odhcp6c_clear_state(STATE_SNTP_IP);
917 odhcp6c_clear_state(STATE_NTP_IP);
918 odhcp6c_clear_state(STATE_NTP_FQDN);
919 odhcp6c_clear_state(STATE_SIP_IP);
920 odhcp6c_clear_state(STATE_SIP_FQDN);
921 odhcp6c_clear_state(STATE_AFTR_NAME);
922 odhcp6c_clear_state(STATE_CER);
923 odhcp6c_clear_state(STATE_S46_MAPT);
924 odhcp6c_clear_state(STATE_S46_MAPE);
925 odhcp6c_clear_state(STATE_S46_LW);
926 odhcp6c_clear_state(STATE_PASSTHRU);
927 }
928
929 // Parse and find all matching IAs
930 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
931 bool passthru = true;
932
933 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
934 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
935 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
936
937 // Test ID
938 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
939 continue;
940
941 uint16_t code = DHCPV6_Success;
942 uint16_t stype, slen;
943 uint8_t *sdata;
944 // Get and handle status code
945 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
946 stype, slen, sdata) {
947 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
948 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
949 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
950
951 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
952
953 if (code == DHCPV6_Success)
954 continue;
955
956 dhcpv6_handle_ia_status_code(orig, ia_hdr,
957 code, mdata, mlen, handled_status_codes, &ret);
958
959
960 if (ret > 0)
961 return ret;
962 break;
963 }
964 }
965
966 if (code != DHCPV6_Success)
967 continue;
968
969 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
970 passthru = false;
971 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
972 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
973 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
974 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
975
976 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
977 passthru = false;
978 }
979 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
980 if (olen % 16 == 0)
981 odhcp6c_add_state(STATE_DNS, odata, olen);
982 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
983 odhcp6c_add_state(STATE_SEARCH, odata, olen);
984 passthru = false;
985 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
986 if (olen % 16 == 0)
987 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
988 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
989 uint16_t stype, slen;
990 uint8_t *sdata;
991 // Test status and bail if error
992 dhcpv6_for_each_option(odata, odata + olen,
993 stype, slen, sdata) {
994 if (slen == 16 && (stype == NTP_MC_ADDR ||
995 stype == NTP_SRV_ADDR))
996 odhcp6c_add_state(STATE_NTP_IP,
997 sdata, slen);
998 else if (slen > 0 && stype == NTP_SRV_FQDN)
999 odhcp6c_add_state(STATE_NTP_FQDN,
1000 sdata, slen);
1001 }
1002 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1003 if (olen == 16)
1004 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1005 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1006 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1007 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1008 refresh = ntohl(*((uint32_t*)odata));
1009 passthru = false;
1010 } else if (otype == DHCPV6_OPT_AUTH) {
1011 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1012 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1013 if (r->protocol == 3 && r->algorithm == 1 &&
1014 r->reconf_type == 1)
1015 memcpy(reconf_key, r->key, sizeof(r->key));
1016 }
1017 passthru = false;
1018 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1019 size_t cur_len;
1020 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1021 if (cur_len == 0)
1022 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1023 passthru = false;
1024 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1025 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1026 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1027 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1028 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1029 passthru = false;
1030 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1031 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1032 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1033 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1034 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1035 passthru = false;
1036 #ifdef EXT_CER_ID
1037 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1038 sizeof(struct dhcpv6_cer_id)) {
1039 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1040 struct in6_addr any = IN6ADDR_ANY_INIT;
1041 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1042 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1043 passthru = false;
1044 #endif
1045 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1046 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1047 passthru = false;
1048 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1049 size_t mape_len;
1050 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1051 if (mape_len == 0)
1052 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1053 passthru = false;
1054 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1055 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1056 passthru = false;
1057 } else if (otype == DHCPV6_OPT_CLIENTID ||
1058 otype == DHCPV6_OPT_SERVERID ||
1059 otype == DHCPV6_OPT_IA_TA ||
1060 otype == DHCPV6_OPT_PREF ||
1061 otype == DHCPV6_OPT_UNICAST ||
1062 otype == DHCPV6_OPT_FQDN ||
1063 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1064 passthru = false;
1065 } else {
1066 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1067 }
1068
1069 if (passthru)
1070 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1071 }
1072
1073 if (orig != DHCPV6_MSG_INFO_REQ) {
1074 // Update refresh timers if no fatal status code was received
1075 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1076 switch (orig) {
1077 case DHCPV6_MSG_RENEW:
1078 // Send further renews if T1 is not set
1079 if (!t1)
1080 ret = -1;
1081 break;
1082 case DHCPV6_MSG_REBIND:
1083 // Send further rebinds if T1 and T2 is not set
1084 if (!t1 && !t2)
1085 ret = -1;
1086 break;
1087
1088 case DHCPV6_MSG_REQUEST:
1089 // All server candidates can be cleared if not yet bound
1090 if (!odhcp6c_is_bound())
1091 dhcpv6_clear_all_server_cand();
1092
1093 default :
1094 break;
1095 }
1096
1097 if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1098 odhcp6c_clear_state(STATE_SERVER_ADDR);
1099 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1100 }
1101 }
1102 }
1103 else if (ret > 0) {
1104 // All server candidates can be cleared if not yet bound
1105 if (!odhcp6c_is_bound())
1106 dhcpv6_clear_all_server_cand();
1107
1108 t1 = refresh;
1109 }
1110
1111 return ret;
1112 }
1113
1114
1115 static int dhcpv6_parse_ia(void *opt, void *end)
1116 {
1117 struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1118 int parsed_ia = 0;
1119 uint32_t t1, t2;
1120 uint16_t otype, olen;
1121 uint8_t *odata;
1122
1123 t1 = ntohl(ia_hdr->t1);
1124 t2 = ntohl(ia_hdr->t2);
1125
1126 if (t1 > t2)
1127 return 0;
1128
1129 // Update address IA
1130 dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1131 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1132 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1133
1134 entry.iaid = ia_hdr->iaid;
1135
1136 if (otype == DHCPV6_OPT_IA_PREFIX) {
1137 struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1138 if (olen + 4U < sizeof(*prefix))
1139 continue;
1140
1141 entry.valid = ntohl(prefix->valid);
1142 entry.preferred = ntohl(prefix->preferred);
1143
1144 if (entry.preferred > entry.valid)
1145 continue;
1146
1147 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1148 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1149 if (entry.t1 > entry.t2)
1150 entry.t1 = entry.t2;
1151
1152 entry.length = prefix->prefix;
1153 entry.target = prefix->addr;
1154 uint16_t stype, slen;
1155 uint8_t *sdata;
1156
1157 #ifdef EXT_PREFIX_CLASS
1158 // Find prefix class, if any
1159 dhcpv6_for_each_option(&prefix[1], odata + olen,
1160 stype, slen, sdata)
1161 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1162 entry.class = sdata[0] << 8 | sdata[1];
1163 #endif
1164
1165 // Parse PD-exclude
1166 bool ok = true;
1167 dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1168 odata + olen, stype, slen, sdata) {
1169 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1170 continue;
1171
1172 uint8_t elen = sdata[0];
1173 if (elen > 64)
1174 elen = 64;
1175
1176 if (elen <= 32 || elen <= entry.length) {
1177 ok = false;
1178 continue;
1179 }
1180
1181
1182 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1183 if (slen <= bytes) {
1184 ok = false;
1185 continue;
1186 }
1187
1188 uint32_t exclude = 0;
1189 do {
1190 exclude = exclude << 8 | sdata[bytes];
1191 } while (--bytes);
1192
1193 exclude >>= 8 - ((elen - entry.length) % 8);
1194 exclude <<= 64 - elen;
1195
1196 // Abusing router & priority fields for exclusion
1197 entry.router = entry.target;
1198 entry.router.s6_addr32[1] |= htonl(exclude);
1199 entry.priority = elen;
1200 }
1201
1202 if (ok) {
1203 odhcp6c_update_entry(STATE_IA_PD, &entry);
1204 parsed_ia++;
1205 }
1206
1207 entry.priority = 0;
1208 memset(&entry.router, 0, sizeof(entry.router));
1209 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1210 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1211 if (olen + 4U < sizeof(*addr))
1212 continue;
1213
1214 entry.preferred = ntohl(addr->preferred);
1215 entry.valid = ntohl(addr->valid);
1216
1217 if (entry.preferred > entry.valid)
1218 continue;
1219
1220 entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1221 entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1222 if (entry.t1 > entry.t2)
1223 entry.t1 = entry.t2;
1224
1225 entry.length = 128;
1226 entry.target = addr->addr;
1227
1228 #ifdef EXT_PREFIX_CLASS
1229 uint16_t stype, slen;
1230 uint8_t *sdata;
1231 // Find prefix class, if any
1232 dhcpv6_for_each_option(&addr[1], odata + olen,
1233 stype, slen, sdata)
1234 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1235 entry.class = sdata[0] << 8 | sdata[1];
1236 #endif
1237
1238 odhcp6c_update_entry(STATE_IA_NA, &entry);
1239 parsed_ia++;
1240 }
1241 }
1242 return parsed_ia;
1243 }
1244
1245
1246 static int dhcpv6_calc_refresh_timers(void)
1247 {
1248 struct odhcp6c_entry *e;
1249 size_t ia_na_entries, ia_pd_entries, i;
1250 int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1251
1252 e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1253 ia_na_entries /= sizeof(*e);
1254 for (i = 0; i < ia_na_entries; i++) {
1255 if (e[i].t1 < l_t1)
1256 l_t1 = e[i].t1;
1257
1258 if (e[i].t2 < l_t2)
1259 l_t2 = e[i].t2;
1260
1261 if (e[i].valid > l_t3)
1262 l_t3 = e[i].valid;
1263 }
1264
1265 e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1266 ia_pd_entries /= sizeof(*e);
1267 for (i = 0; i < ia_pd_entries; i++) {
1268 if (e[i].t1 < l_t1)
1269 l_t1 = e[i].t1;
1270
1271 if (e[i].t2 < l_t2)
1272 l_t2 = e[i].t2;
1273
1274 if (e[i].valid > l_t3)
1275 l_t3 = e[i].valid;
1276 }
1277
1278 if (ia_pd_entries || ia_na_entries) {
1279 t1 = l_t1;
1280 t2 = l_t2;
1281 t3 = l_t3;
1282 } else {
1283 t1 = 600;
1284 }
1285
1286 return (int)(ia_pd_entries + ia_na_entries);
1287 }
1288
1289
1290 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1291 const void *status_msg, const int len)
1292 {
1293 uint8_t buf[len + 3];
1294
1295 memset(buf, 0, sizeof(buf));
1296 if (len) {
1297 buf[0] = '(';
1298 memcpy(&buf[1], status_msg, len);
1299 buf[len + 1] = ')';
1300 }
1301
1302 syslog(LOG_WARNING, "Server returned %s status %i %s",
1303 scope, code, buf);
1304 }
1305
1306
1307 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1308 const uint16_t code, const void *status_msg, const int len,
1309 int *ret)
1310 {
1311 dhcpv6_log_status_code(code, "message", status_msg, len);
1312
1313 switch (code) {
1314 case DHCPV6_UnspecFail:
1315 // Generic failure
1316 *ret = 0;
1317 break;
1318
1319 case DHCPV6_UseMulticast:
1320 // TODO handle multicast status code
1321 break;
1322
1323 case DHCPV6_NoAddrsAvail:
1324 case DHCPV6_NoPrefixAvail:
1325 if (orig == DHCPV6_MSG_REQUEST)
1326 *ret = 0; // Failure
1327 break;
1328
1329 default:
1330 break;
1331 }
1332 }
1333
1334
1335 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1336 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1337 const void *status_msg, const int len,
1338 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1339 {
1340 dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1341 "IA_NA" : "IA_PD", status_msg, len);
1342
1343 switch (code) {
1344 case DHCPV6_NoBinding:
1345 switch (orig) {
1346 case DHCPV6_MSG_RENEW:
1347 case DHCPV6_MSG_REBIND:
1348 if ((*ret > 0) && !handled_status_codes[code])
1349 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1350 break;
1351
1352 default:
1353 break;
1354 }
1355 break;
1356
1357 case DHCPV6_NoAddrsAvail:
1358 case DHCPV6_NoPrefixAvail:
1359 switch (orig) {
1360 case DHCPV6_MSG_REQUEST:
1361 if (*ret != 0)
1362 *ret = 0;
1363 break;
1364 default:
1365 break;
1366 }
1367 break;
1368
1369 case DHCPV6_NotOnLink:
1370 // TODO handle not onlink in case of confirm
1371 break;
1372
1373 default:
1374 break;
1375 }
1376 }
1377
1378 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1379 {
1380 size_t cand_len, i;
1381 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1382
1383 // Remove identical duid server candidate
1384 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1385 if (cand->duid_len == c[i].duid_len &&
1386 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1387 free(c[i].ia_na);
1388 free(c[i].ia_pd);
1389 odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1390 break;
1391 }
1392 }
1393
1394 for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1395 i < cand_len / sizeof(*c); ++i) {
1396 if (c[i].preference < cand->preference)
1397 break;
1398 }
1399
1400 odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1401 }
1402
1403 static void dhcpv6_clear_all_server_cand(void)
1404 {
1405 size_t cand_len, i;
1406 struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1407
1408 // Server candidates need deep delete for IA_NA/IA_PD
1409 for (i = 0; i < cand_len / sizeof(*c); ++i) {
1410 free(c[i].ia_na);
1411 free(c[i].ia_pd);
1412 }
1413 odhcp6c_clear_state(STATE_SERVER_CAND);
1414 }
1415
1416 int dhcpv6_promote_server_cand(void)
1417 {
1418 size_t cand_len;
1419 struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1420 uint16_t hdr[2];
1421 int ret = DHCPV6_STATELESS;
1422
1423 // Clear lingering candidate state info
1424 odhcp6c_clear_state(STATE_SERVER_ID);
1425 odhcp6c_clear_state(STATE_IA_NA);
1426 odhcp6c_clear_state(STATE_IA_PD);
1427
1428 if (!cand_len)
1429 return -1;
1430
1431 if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1432 na_mode = IA_MODE_NONE;
1433
1434 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1435 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1436
1437 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1438 }
1439
1440 hdr[0] = htons(DHCPV6_OPT_SERVERID);
1441 hdr[1] = htons(cand->duid_len);
1442 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1443 odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1444 accept_reconfig = cand->wants_reconfigure;
1445 if (cand->ia_na_len) {
1446 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1447 free(cand->ia_na);
1448 if (na_mode != IA_MODE_NONE)
1449 ret = DHCPV6_STATEFUL;
1450 }
1451 if (cand->ia_pd_len) {
1452 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1453 free(cand->ia_pd);
1454 if (request_prefix)
1455 ret = DHCPV6_STATEFUL;
1456 }
1457
1458 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1459 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1460
1461 odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1462
1463 return ret;
1464 }
Openwrt DHCPv6 Client