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Sources/odhcp6c/src/dhcpv6.c

  1 /**
  2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
  3  * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU General Public License v2 as published by
  7  * the Free Software Foundation.
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  */
 15 
 16 #include <time.h>
 17 #include <fcntl.h>
 18 #include <errno.h>
 19 #include <inttypes.h>
 20 #include <stdlib.h>
 21 #include <signal.h>
 22 #include <limits.h>
 23 #include <resolv.h>
 24 #include <string.h>
 25 #include <unistd.h>
 26 #include <syslog.h>
 27 #include <stdbool.h>
 28 #include <ctype.h>
 29 #include <sys/time.h>
 30 #include <sys/ioctl.h>
 31 #include <sys/socket.h>
 32 #include <arpa/inet.h>
 33 #include <netinet/in.h>
 34 
 35 #include <net/if.h>
 36 #include <net/ethernet.h>
 37 
 38 #include "odhcp6c.h"
 39 #ifdef USE_LIBUBOX
 40 #include <libubox/md5.h>
 41 #else
 42 #include "md5.h"
 43 #endif
 44 
 45 
 46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
 47                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
 48 #define DHCPV6_CLIENT_PORT 546
 49 #define DHCPV6_SERVER_PORT 547
 50 #define DHCPV6_DUID_LLADDR 3
 51 #define DHCPV6_REQ_DELAY 1
 52 
 53 #define DHCPV6_SOL_MAX_RT_MIN 60
 54 #define DHCPV6_SOL_MAX_RT_MAX 86400
 55 #define DHCPV6_INF_MAX_RT_MIN 60
 56 #define DHCPV6_INF_MAX_RT_MAX 86400
 57 
 58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 59                 const uint8_t transaction[3], enum dhcpv6_msg type,
 60                 const struct in6_addr *daddr);
 61 
 62 static unsigned int dhcpv6_parse_ia(void *opt, void *end);
 63 
 64 static unsigned 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 enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
107 static bool stateful_only_mode = false;
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 static char *dhcpv6_msg_to_str(enum dhcpv6_msg msg)
127 {
128         switch (msg) {
129         case DHCPV6_MSG_SOLICIT:
130                 return "SOLICIT";
131 
132         case DHCPV6_MSG_ADVERT:
133                 return "ADVERTISE";
134 
135         case DHCPV6_MSG_REQUEST:
136                 return "REQUEST";
137 
138         case DHCPV6_MSG_RENEW:
139                 return "RENEW";
140 
141         case DHCPV6_MSG_REBIND:
142                 return "REBIND";
143 
144         case DHCPV6_MSG_REPLY:
145                 return "REPLY";
146 
147         case DHCPV6_MSG_RELEASE:
148                 return "RELEASE";
149 
150         case DHCPV6_MSG_DECLINE:
151                 return "DECLINE";
152 
153         case DHCPV6_MSG_RECONF:
154                 return "RECONFIGURE";
155 
156         case DHCPV6_MSG_INFO_REQ:
157                 return "INFORMATION REQUEST";
158 
159         default:
160                 break;
161         }
162 
163         return "UNKNOWN";
164 }
165 
166 static char *dhcpv6_status_code_to_str(uint16_t code)
167 {
168         switch (code) {
169         case DHCPV6_Success:
170                 return "Success";
171 
172         case DHCPV6_UnspecFail:
173                 return "Unspecified Failure";
174 
175         case DHCPV6_NoAddrsAvail:
176                 return "No Address Available";
177 
178         case DHCPV6_NoBinding:
179                 return "No Binding";
180 
181         case DHCPV6_NotOnLink:
182                 return "Not On Link";
183 
184         case DHCPV6_UseMulticast:
185                 return "Use Multicast";
186 
187         case DHCPV6_NoPrefixAvail:
188                 return "No Prefix Available";
189 
190         default:
191                 break;
192         }
193 
194         return "Unknown";
195 }
196 
197 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
198 {
199         client_options = options;
200         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
201 
202         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
203         if (sock < 0)
204                 goto failure;
205 
206         // Detect interface
207         struct ifreq ifr;
208         memset(&ifr, 0, sizeof(ifr));
209         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
210         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
211                 goto failure;
212 
213         ifindex = ifr.ifr_ifindex;
214 
215         // Create client DUID
216         size_t client_id_len;
217         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
218         if (client_id_len == 0) {
219                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
220                                 DHCPV6_DUID_LLADDR, 0, 1};
221 
222                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
223                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
224 
225                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
226                 struct ifreq ifs[100], *ifp, *ifend;
227                 struct ifconf ifc;
228                 ifc.ifc_req = ifs;
229                 ifc.ifc_len = sizeof(ifs);
230 
231                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
232                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
233                         // If our interface doesn't have an address...
234                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
235                         for (ifp = ifc.ifc_req; ifp < ifend &&
236                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
237                                 memcpy(ifr.ifr_name, ifp->ifr_name,
238                                                 sizeof(ifr.ifr_name));
239                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
240                                         continue;
241 
242                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
243                                                 ETHER_ADDR_LEN);
244                         }
245                 }
246 
247                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
248         }
249 
250         // Create ORO
251         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
252                 uint16_t oro[] = {
253                         htons(DHCPV6_OPT_SIP_SERVER_D),
254                         htons(DHCPV6_OPT_SIP_SERVER_A),
255                         htons(DHCPV6_OPT_DNS_SERVERS),
256                         htons(DHCPV6_OPT_DNS_DOMAIN),
257                         htons(DHCPV6_OPT_SNTP_SERVERS),
258                         htons(DHCPV6_OPT_NTP_SERVER),
259                         htons(DHCPV6_OPT_AFTR_NAME),
260                         htons(DHCPV6_OPT_PD_EXCLUDE),
261 #ifdef EXT_CER_ID
262                         htons(DHCPV6_OPT_CER_ID),
263 #endif
264                         htons(DHCPV6_OPT_S46_CONT_MAPE),
265                         htons(DHCPV6_OPT_S46_CONT_MAPT),
266                         htons(DHCPV6_OPT_S46_CONT_LW),
267                 };
268                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
269         }
270         // Required oro
271         uint16_t req_oro[] = {
272                 htons(DHCPV6_OPT_INF_MAX_RT),
273                 htons(DHCPV6_OPT_SOL_MAX_RT),
274                 htons(DHCPV6_OPT_INFO_REFRESH),
275         };
276         odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro));
277 
278         // Configure IPv6-options
279         int val = 1;
280         if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
281                 goto failure;
282 
283         if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
284                 goto failure;
285 
286         if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
287                 goto failure;
288 
289         if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
290                 goto failure;
291 
292         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
293                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
294 
295         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
296                 goto failure;
297 
298         return 0;
299 
300 failure:
301         if (sock >= 0)
302                 close(sock);
303 
304         return -1;
305 }
306 
307 enum {
308         IOV_HDR=0,
309         IOV_ORO,
310         IOV_CL_ID,
311         IOV_SRV_ID,
312         IOV_OPTS,
313         IOV_RECONF_ACCEPT,
314         IOV_FQDN,
315         IOV_HDR_IA_NA,
316         IOV_IA_NA,
317         IOV_IA_PD,
318         IOV_TOTAL
319 };
320 
321 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd, bool stateful_only)
322 {
323         int mode = DHCPV6_UNKNOWN;
324 
325         na_mode = na;
326         pd_mode = pd;
327         stateful_only_mode = stateful_only;
328 
329         if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
330                 mode = DHCPV6_STATELESS;
331         else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
332                 mode = DHCPV6_STATEFUL;
333 
334         return mode;
335 }
336 
337 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
338 {
339         // Build FQDN
340         char fqdn_buf[256];
341         gethostname(fqdn_buf, sizeof(fqdn_buf));
342         struct {
343                 uint16_t type;
344                 uint16_t len;
345                 uint8_t flags;
346                 uint8_t data[256];
347         } fqdn;
348         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
349                         sizeof(fqdn.data), NULL, NULL);
350         fqdn.type = htons(DHCPV6_OPT_FQDN);
351         fqdn.len = htons(fqdn_len - 4);
352         fqdn.flags = 0;
353 
354         // Build Client ID
355         size_t cl_id_len;
356         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
357 
358         // Get Server ID
359         size_t srv_id_len;
360         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
361 
362         // Build IA_PDs
363         size_t ia_pd_entries = 0, ia_pd_len = 0;
364         uint8_t *ia_pd;
365 
366         if (type == DHCPV6_MSG_SOLICIT) {
367                 odhcp6c_clear_state(STATE_IA_PD);
368                 size_t n_prefixes;
369                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
370                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
371 
372                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
373 
374                 for (size_t i = 0; i < n_prefixes; i++) {
375                         struct dhcpv6_ia_hdr hdr_ia_pd = {
376                                 htons(DHCPV6_OPT_IA_PD),
377                                 htons(sizeof(hdr_ia_pd) - 4 +
378                                       sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
379                                 request_prefixes[i].iaid, 0, 0
380                         };
381                         struct dhcpv6_ia_prefix pref = {
382                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
383                                 .len = htons(sizeof(pref) - 4),
384                                 .prefix = request_prefixes[i].length
385                         };
386                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
387                         ia_pd_len += sizeof(hdr_ia_pd);
388                         if (request_prefixes[i].length) {
389                                 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
390                                 ia_pd_len += sizeof(pref);
391                         }
392                 }
393         } else {
394                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
395                 ia_pd_entries /= sizeof(*e);
396 
397                 // we're too lazy to count our distinct IAIDs,
398                 // so just allocate maximally needed space
399                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
400                                         sizeof(struct dhcpv6_ia_hdr)));
401 
402                 for (size_t i = 0; i < ia_pd_entries; ++i) {
403                         uint32_t iaid = e[i].iaid;
404 
405                         // check if this is an unprocessed IAID and skip if not.
406                         int new_iaid = 1;
407                         for (int j = i-1; j >= 0; j--) {
408                                 if (e[j].iaid == iaid) {
409                                         new_iaid = 0;
410                                         break;
411                                 }
412                         }
413 
414                         if (!new_iaid)
415                                 continue;
416 
417                         // construct header
418                         struct dhcpv6_ia_hdr hdr_ia_pd = {
419                                 htons(DHCPV6_OPT_IA_PD),
420                                 htons(sizeof(hdr_ia_pd) - 4),
421                                 iaid, 0, 0
422                         };
423 
424                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
425                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
426                         ia_pd_len += sizeof(hdr_ia_pd);
427 
428                         for (size_t j = i; j < ia_pd_entries; j++) {
429                                 if (e[j].iaid != iaid)
430                                         continue;
431 
432                                 uint8_t ex_len = 0;
433                                 if (e[j].priority > 0)
434                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
435 
436                                 struct dhcpv6_ia_prefix p = {
437                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
438                                         .len = htons(sizeof(p) - 4U + ex_len),
439                                         .prefix = e[j].length,
440                                         .addr = e[j].target
441                                 };
442 
443                                 if (type == DHCPV6_MSG_REQUEST) {
444                                         p.preferred = htonl(e[j].preferred);
445                                         p.valid = htonl(e[j].valid);
446                                 }
447 
448                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
449                                 ia_pd_len += sizeof(p);
450 
451                                 if (ex_len) {
452                                         ia_pd[ia_pd_len++] = 0;
453                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
454                                         ia_pd[ia_pd_len++] = 0;
455                                         ia_pd[ia_pd_len++] = ex_len - 4;
456                                         ia_pd[ia_pd_len++] = e[j].priority;
457 
458                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
459                                         excl >>= (64 - e[j].priority);
460                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
461 
462                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
463                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
464                                         ia_pd_len += ex_len - 5;
465                                 }
466 
467                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
468                         }
469                 }
470         }
471 
472         // Build IA_NAs
473         size_t ia_na_entries, ia_na_len = 0;
474         void *ia_na = NULL;
475         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
476         ia_na_entries /= sizeof(*e);
477 
478         struct dhcpv6_ia_hdr hdr_ia_na = {
479                 htons(DHCPV6_OPT_IA_NA),
480                 htons(sizeof(hdr_ia_na) - 4),
481                 htonl(1), 0, 0
482         };
483 
484         struct dhcpv6_ia_addr pa[ia_na_entries];
485         for (size_t i = 0; i < ia_na_entries; ++i) {
486                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
487                 pa[i].len = htons(sizeof(pa[i]) - 4U);
488                 pa[i].addr = e[i].target;
489 
490                 if (type == DHCPV6_MSG_REQUEST) {
491                         pa[i].preferred = htonl(e[i].preferred);
492                         pa[i].valid = htonl(e[i].valid);
493                 } else {
494                         pa[i].preferred = 0;
495                         pa[i].valid = 0;
496                 }
497         }
498 
499         ia_na = pa;
500         ia_na_len = sizeof(pa);
501         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
502 
503         // Reconfigure Accept
504         struct {
505                 uint16_t type;
506                 uint16_t length;
507         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
508 
509         // Option list
510         size_t opts_len;
511         void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
512 
513         // Option Request List
514         size_t oro_entries, oro_len = 0;
515         uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries);
516 
517         oro_entries /= sizeof(*s_oro);
518         oro = alloca(oro_entries * sizeof(*oro));
519 
520         for (size_t i = 0; i < oro_entries; i++) {
521                 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i]));
522 
523                 if (opt) {
524                         if (!(opt->flags & OPT_ORO))
525                                 continue;
526 
527                         if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT)
528                                 continue;
529 
530                         if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ)
531                                 continue;
532 
533                         if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ)
534                                 continue;
535                 }
536 
537                 oro[oro_len++] = s_oro[i];
538         }
539         oro_len *= sizeof(*oro);
540 
541         // Prepare Header
542         struct {
543                 uint8_t type;
544                 uint8_t trid[3];
545                 uint16_t elapsed_type;
546                 uint16_t elapsed_len;
547                 uint16_t elapsed_value;
548                 uint16_t oro_type;
549                 uint16_t oro_len;
550         } hdr = {
551                 type, {trid[0], trid[1], trid[2]},
552                 htons(DHCPV6_OPT_ELAPSED), htons(2),
553                         htons((ecs > 0xffff) ? 0xffff : ecs),
554                 htons(DHCPV6_OPT_ORO), htons(oro_len),
555         };
556 
557         struct iovec iov[IOV_TOTAL] = {
558                 [IOV_HDR] = {&hdr, sizeof(hdr)},
559                 [IOV_ORO] = {oro, oro_len},
560                 [IOV_CL_ID] = {cl_id, cl_id_len},
561                 [IOV_SRV_ID] = {srv_id, srv_id_len},
562                 [IOV_OPTS] = { opts, opts_len },
563                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
564                 [IOV_FQDN] = {&fqdn, fqdn_len},
565                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
566                 [IOV_IA_NA] = {ia_na, ia_na_len},
567                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
568         };
569 
570         size_t cnt = IOV_TOTAL;
571         if (type == DHCPV6_MSG_INFO_REQ)
572                 cnt = IOV_HDR_IA_NA;
573 
574         // Disable IAs if not used
575         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
576                 iov[IOV_HDR_IA_NA].iov_len = 0;
577 
578         if (na_mode == IA_MODE_NONE)
579                 iov[IOV_HDR_IA_NA].iov_len = 0;
580 
581         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
582                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
583                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
584 
585         if (!(client_options & DHCPV6_CLIENT_FQDN))
586                 iov[IOV_FQDN].iov_len = 0;
587 
588         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
589                 0, ALL_DHCPV6_RELAYS, ifindex};
590         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
591                         .msg_iov = iov, .msg_iovlen = cnt};
592 
593         switch (type) {
594         case DHCPV6_MSG_REQUEST:
595         case DHCPV6_MSG_RENEW:
596         case DHCPV6_MSG_RELEASE:
597         case DHCPV6_MSG_DECLINE:
598                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
599                         odhcp6c_addr_in_scope(&server_addr)) {
600                         srv.sin6_addr = server_addr;
601                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
602                                 srv.sin6_scope_id = 0;
603                 }
604                 break;
605         default:
606                 break;
607         }
608 
609         if (sendmsg(sock, &msg, 0) < 0) {
610                 char in6_str[INET6_ADDRSTRLEN];
611 
612                 syslog(LOG_ERR, "Failed to send %s message to %s (%s)",
613                         dhcpv6_msg_to_str(type),
614                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
615                                 in6_str, sizeof(in6_str)), strerror(errno));
616         }
617 }
618 
619 static int64_t dhcpv6_rand_delay(int64_t time)
620 {
621         int random;
622         odhcp6c_random(&random, sizeof(random));
623 
624         return (time * ((int64_t)random % 1000LL)) / 10000LL;
625 }
626 
627 int dhcpv6_request(enum dhcpv6_msg type)
628 {
629         uint8_t rc = 0;
630         uint64_t timeout = UINT32_MAX;
631         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
632 
633         if (retx->delay) {
634                 struct timespec ts = {0, 0};
635                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
636 
637                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
638         }
639 
640         if (type == DHCPV6_MSG_UNKNOWN)
641                 timeout = t1;
642         else if (type == DHCPV6_MSG_RENEW)
643                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
644         else if (type == DHCPV6_MSG_REBIND)
645                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
646 
647         if (timeout == 0)
648                 return -1;
649 
650         syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
651                         retx->name, timeout, retx->max_rc);
652 
653         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
654 
655         // Generate transaction ID
656         uint8_t trid[3] = {0, 0, 0};
657         if (type != DHCPV6_MSG_UNKNOWN)
658                 odhcp6c_random(trid, sizeof(trid));
659 
660         ssize_t len = -1;
661         int64_t rto = 0;
662 
663         do {
664                 if (rto == 0) {
665                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
666 
667                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
668                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
669                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
670 
671                         rto = (retx->init_timeo * 1000 + delay);
672                 } else
673                         rto = (2 * rto + dhcpv6_rand_delay(rto));
674 
675                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
676                         rto = retx->max_timeo * 1000 +
677                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
678 
679                 // Calculate end for this round and elapsed time
680                 uint64_t round_end = round_start + rto;
681                 elapsed = round_start - start;
682 
683                 // Don't wait too long if timeout differs from infinite
684                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
685                         round_end = timeout * 1000 + start;
686 
687                 // Built and send package
688                 switch (type) {
689                 case DHCPV6_MSG_UNKNOWN:
690                         break;
691                 default:
692                         syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
693                                         retx->name, elapsed, rc);
694                         // Fall through
695                 case DHCPV6_MSG_SOLICIT:
696                 case DHCPV6_MSG_INFO_REQ:
697                         dhcpv6_send(type, trid, elapsed / 10);
698                         rc++;
699                 }
700 
701                 // Receive rounds
702                 for (; len < 0 && (round_start < round_end);
703                                 round_start = odhcp6c_get_milli_time()) {
704                         uint8_t buf[1536];
705                         union {
706                                 struct cmsghdr hdr;
707                                 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
708                         } cmsg_buf;
709                         struct iovec iov = {buf, sizeof(buf)};
710                         struct sockaddr_in6 addr;
711                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
712                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
713                                         .msg_controllen = sizeof(cmsg_buf)};
714                         struct in6_pktinfo *pktinfo = NULL;
715                         const struct dhcpv6_header *hdr = (const struct dhcpv6_header *)buf;
716 
717                         // Check for pending signal
718                         if (odhcp6c_signal_process())
719                                 return -1;
720 
721                         // Set timeout for receiving
722                         uint64_t t = round_end - round_start;
723                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
724                         if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
725                                         &tv, sizeof(tv)) < 0)
726                                 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
727                                                 strerror(errno));
728 
729                         // Receive cycle
730                         len = recvmsg(sock, &msg, 0);
731                         if (len < 0)
732                                 continue;
733 
734                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
735                                 ch = CMSG_NXTHDR(&msg, ch)) {
736                                 if (ch->cmsg_level == SOL_IPV6 &&
737                                         ch->cmsg_type == IPV6_PKTINFO) {
738                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
739                                         break;
740                                 }
741                         }
742 
743                         if (pktinfo == NULL) {
744                                 len = -1;
745                                 continue;
746                         }
747 
748                         if (!dhcpv6_response_is_valid(buf, len, trid,
749                                                         type, &pktinfo->ipi6_addr)) {
750                                 len = -1;
751                                 continue;
752                         }
753 
754                         uint8_t *opt = &buf[4];
755                         uint8_t *opt_end = opt + len - 4;
756 
757                         round_start = odhcp6c_get_milli_time();
758                         elapsed = round_start - start;
759                         syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms",
760                                dhcpv6_msg_to_str(hdr->msg_type), elapsed);
761 
762                         if (retx->handler_reply)
763                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
764 
765                         if (len > 0 && round_end - round_start > 1000)
766                                 round_end = 1000 + round_start;
767                 }
768 
769                 // Allow
770                 if (retx->handler_finish)
771                         len = retx->handler_finish();
772         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
773                         (!retx->max_rc || rc < retx->max_rc));
774         return len;
775 }
776 
777 // Message validation checks according to RFC3315 chapter 15
778 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
779                 const uint8_t transaction[3], enum dhcpv6_msg type,
780                 const struct in6_addr *daddr)
781 {
782         const struct dhcpv6_header *rep = buf;
783         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
784                         transaction, sizeof(rep->tr_id)))
785                 return false; // Invalid reply
786 
787         if (type == DHCPV6_MSG_SOLICIT) {
788                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
789                                 rep->msg_type != DHCPV6_MSG_REPLY)
790                         return false;
791 
792         } else if (type == DHCPV6_MSG_UNKNOWN) {
793                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
794                         return false;
795 
796         } else if (rep->msg_type != DHCPV6_MSG_REPLY)
797                 return false;
798 
799         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
800                 rcmsg = DHCPV6_MSG_UNKNOWN;
801         uint16_t otype, olen = UINT16_MAX;
802         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
803                 ia_present = false, options_valid = true;
804 
805         size_t client_id_len, server_id_len;
806         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
807         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
808 
809         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
810                 if (otype == DHCPV6_OPT_CLIENTID) {
811                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
812                                         &odata[-4], client_id, client_id_len);
813                 } else if (otype == DHCPV6_OPT_SERVERID) {
814                         if (server_id_len)
815                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
816                                                 &odata[-4], server_id, server_id_len);
817                         else
818                                 serverid_ok = true;
819                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
820                                 sizeof(struct dhcpv6_auth_reconfigure)) {
821                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
822                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
823                                 continue;
824 
825                         md5_ctx_t md5;
826                         uint8_t serverhash[16], secretbytes[64];
827                         uint32_t hash[4];
828                         memcpy(serverhash, r->key, sizeof(serverhash));
829                         memset(r->key, 0, sizeof(r->key));
830 
831                         memset(secretbytes, 0, sizeof(secretbytes));
832                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
833 
834                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
835                                 secretbytes[i] ^= 0x36;
836 
837                         md5_begin(&md5);
838                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
839                         md5_hash(buf, len, &md5);
840                         md5_end(hash, &md5);
841 
842                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
843                                 secretbytes[i] ^= 0x36;
844                                 secretbytes[i] ^= 0x5c;
845                         }
846 
847                         md5_begin(&md5);
848                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
849                         md5_hash(hash, 16, &md5);
850                         md5_end(hash, &md5);
851 
852                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
853                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
854                         rcmsg = odata[0];
855                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
856                         ia_present = true;
857                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
858                                 options_valid = false;
859                 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
860                                 (otype == DHCPV6_OPT_PD_EXCLUDE))
861                         // Options are not allowed on global level
862                         options_valid = false;
863         }
864 
865         if (!options_valid || ((odata + olen) > end))
866                 return false;
867 
868         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
869                 return false;
870 
871         if (rep->msg_type == DHCPV6_MSG_RECONF) {
872                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
873                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
874                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
875                         return false;
876         }
877 
878         return clientid_ok && serverid_ok;
879 }
880 
881 int dhcpv6_poll_reconfigure(void)
882 {
883         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
884 
885         switch (ret) {
886         /*
887          * Only RENEW/REBIND/INFORMATION REQUEST
888          * message transmission can be requested
889          * by a RECONFIGURE
890          */
891         case DHCPV6_MSG_RENEW:
892         case DHCPV6_MSG_REBIND:
893         case DHCPV6_MSG_INFO_REQ:
894                 ret = dhcpv6_request(ret);
895                 break;
896 
897         default:
898                 break;
899         }
900 
901         return ret;
902 }
903 
904 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
905                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
906 {
907         uint16_t otype, olen;
908         uint8_t *odata;
909         enum dhcpv6_msg msg = DHCPV6_MSG_UNKNOWN;
910 
911         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
912                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
913                         switch (odata[0]) {
914                         case DHCPV6_MSG_REBIND:
915                                 if (t2 != UINT32_MAX)
916                                         t2 = 0;
917                         // Fall through
918                         case DHCPV6_MSG_RENEW:
919                                 if (t1 != UINT32_MAX)
920                                         t1 = 0;
921                         // Fall through
922                         case DHCPV6_MSG_INFO_REQ:
923                                 msg = odata[0];
924                                 syslog(LOG_NOTICE, "Need to respond with %s in reply to %s",
925                                        dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF));
926                                 break;
927 
928                         default:
929                                 break;
930                         }
931                 }
932         }
933 
934         if (msg != DHCPV6_MSG_UNKNOWN)
935                 dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
936 
937         return (msg == DHCPV6_MSG_UNKNOWN? -1: (int)msg);
938 }
939 
940 // Collect all advertised servers
941 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
942                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
943 {
944         uint16_t olen, otype;
945         uint8_t *odata, pref = 0;
946         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
947                                         IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
948                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
949         bool have_na = false;
950         int have_pd = 0;
951 
952         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
953                 if (orig == DHCPV6_MSG_SOLICIT &&
954                                 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
955                                  (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
956                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
957                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
958                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
959                 }
960 
961                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
962                         memcpy(cand.duid, odata, olen);
963                         cand.duid_len = olen;
964                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
965                                 cand.preference >= 0) {
966                         cand.preference = pref = odata[0];
967                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
968                         if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
969                                 cand.server_addr = *(struct in6_addr *)odata;
970 
971                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
972                         cand.wants_reconfigure = true;
973                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
974                         uint32_t sol_max_rt = ntohl_unaligned(odata);
975                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
976                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
977                                 cand.sol_max_rt = sol_max_rt;
978 
979                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
980                         uint32_t inf_max_rt = ntohl_unaligned(odata);
981                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
982                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
983                                 cand.inf_max_rt = inf_max_rt;
984 
985                 } else if (otype == DHCPV6_OPT_IA_PD &&
986                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
987                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
988                         uint8_t *oend = odata + olen, *d;
989                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
990                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
991                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
992                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
993                                         have_pd = p->prefix;
994                                 }
995                         }
996                 } else if (otype == DHCPV6_OPT_IA_NA &&
997                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
998                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
999                         uint8_t *oend = odata + olen, *d;
1000 
1001                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
1002                                 if (otype == DHCPV6_OPT_IA_ADDR &&
1003                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
1004                                         have_na = true;
1005                         }
1006                 }
1007         }
1008 
1009         if ((stateful_only_mode && !have_na && !have_pd) ||
1010                         (!have_na && na_mode == IA_MODE_FORCE) ||
1011                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
1012                 /*
1013                  * RFC7083 states to process the SOL_MAX_RT and
1014                  * INF_MAX_RT options even if the DHCPv6 server
1015                  * did not propose any IA_NA and/or IA_PD
1016                  */
1017                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
1018                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
1019                 return -1;
1020         }
1021 
1022         if (na_mode != IA_MODE_NONE && !have_na) {
1023                 cand.has_noaddravail = true;
1024                 cand.preference -= 1000;
1025         }
1026 
1027         if (pd_mode != IA_MODE_NONE) {
1028                 if (have_pd)
1029                         cand.preference += 2000 + (128 - have_pd);
1030                 else
1031                         cand.preference -= 2000;
1032         }
1033 
1034         if (cand.duid_len > 0) {
1035                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
1036                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
1037                 dhcpv6_add_server_cand(&cand);
1038         }
1039 
1040         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
1041 }
1042 
1043 static int dhcpv6_commit_advert(void)
1044 {
1045         return dhcpv6_promote_server_cand();
1046 }
1047 
1048 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
1049                 const void *opt, const void *end, const struct sockaddr_in6 *from)
1050 {
1051         dhcpv6_handle_advert(orig, rc, opt, end, from);
1052         if (dhcpv6_commit_advert() < 0)
1053                 return -1;
1054 
1055         return dhcpv6_handle_reply(orig, rc, opt, end, from);
1056 }
1057 
1058 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
1059                 const void *opt, const void *end, const struct sockaddr_in6 *from)
1060 {
1061         uint8_t *odata;
1062         uint16_t otype, olen;
1063         uint32_t refresh = 86400;
1064         int ret = 1;
1065         unsigned int state_IAs;
1066         unsigned int updated_IAs = 0;
1067         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
1068 
1069         odhcp6c_expire(true);
1070 
1071         if (orig == DHCPV6_MSG_UNKNOWN) {
1072                 static time_t last_update = 0;
1073                 time_t now = odhcp6c_get_milli_time() / 1000;
1074 
1075                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
1076                 last_update = now;
1077 
1078                 if (t1 != UINT32_MAX)
1079                         t1 -= elapsed;
1080 
1081                 if (t2 != UINT32_MAX)
1082                         t2 -= elapsed;
1083 
1084                 if (t3 != UINT32_MAX)
1085                         t3 -= elapsed;
1086 
1087                 if (t1 < 0)
1088                         t1 = 0;
1089 
1090                 if (t2 < 0)
1091                         t2 = 0;
1092 
1093                 if (t3 < 0)
1094                         t3 = 0;
1095         }
1096 
1097         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1098                 // Delete NA and PD we have in the state from the Advert
1099                 odhcp6c_clear_state(STATE_IA_NA);
1100                 odhcp6c_clear_state(STATE_IA_PD);
1101         }
1102 
1103         if (opt) {
1104                 odhcp6c_clear_state(STATE_DNS);
1105                 odhcp6c_clear_state(STATE_SEARCH);
1106                 odhcp6c_clear_state(STATE_SNTP_IP);
1107                 odhcp6c_clear_state(STATE_NTP_IP);
1108                 odhcp6c_clear_state(STATE_NTP_FQDN);
1109                 odhcp6c_clear_state(STATE_SIP_IP);
1110                 odhcp6c_clear_state(STATE_SIP_FQDN);
1111                 odhcp6c_clear_state(STATE_AFTR_NAME);
1112                 odhcp6c_clear_state(STATE_CER);
1113                 odhcp6c_clear_state(STATE_S46_MAPT);
1114                 odhcp6c_clear_state(STATE_S46_MAPE);
1115                 odhcp6c_clear_state(STATE_S46_LW);
1116                 odhcp6c_clear_state(STATE_PASSTHRU);
1117                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1118 
1119                 // Parse and find all matching IAs
1120                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1121                         struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1122 
1123                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1124                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1125                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1126 
1127                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1128                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1129                                         continue;
1130 
1131                                 // Test ID
1132                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1133                                         continue;
1134 
1135                                 uint16_t code = DHCPV6_Success;
1136                                 uint16_t stype, slen;
1137                                 uint8_t *sdata;
1138                                 // Get and handle status code
1139                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1140                                                 stype, slen, sdata) {
1141                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1142                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1143                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1144 
1145                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1146 
1147                                                 if (code == DHCPV6_Success)
1148                                                         continue;
1149 
1150                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1151                                                         code, mdata, mlen, handled_status_codes, &ret);
1152 
1153                                                 if (ret > 0)
1154                                                         return ret;
1155 
1156                                                 break;
1157                                         }
1158                                 }
1159 
1160                                 if (code != DHCPV6_Success)
1161                                         continue;
1162 
1163                                 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1164                         } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1165                                 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1166                                         server_addr = *(struct in6_addr *)odata;
1167 
1168                         }
1169                         else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1170                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1171                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1172                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1173 
1174                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1175                         } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1176                                 if (olen % 16 == 0)
1177                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1178                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1179                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1180                         else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1181                                 if (olen % 16 == 0)
1182                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1183                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1184                                 uint16_t stype, slen;
1185                                 uint8_t *sdata;
1186                                 // Test status and bail if error
1187                                 dhcpv6_for_each_option(odata, odata + olen,
1188                                                 stype, slen, sdata) {
1189                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1190                                                         stype == NTP_SRV_ADDR))
1191                                                 odhcp6c_add_state(STATE_NTP_IP,
1192                                                                 sdata, slen);
1193                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1194                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1195                                                                 sdata, slen);
1196                                 }
1197                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1198                                 if (olen == 16)
1199                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1200                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1201                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1202                         else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1203                                 refresh = ntohl_unaligned(odata);
1204                         } else if (otype == DHCPV6_OPT_AUTH) {
1205                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1206                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1207                                         if (r->protocol == 3 && r->algorithm == 1 &&
1208                                                         r->reconf_type == 1)
1209                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1210                                 }
1211                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1212                                 size_t cur_len;
1213                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1214                                 if (cur_len == 0)
1215                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1216                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1217                                 uint32_t sol_max_rt = ntohl_unaligned(odata);
1218                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1219                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1220                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1221                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1222                                 uint32_t inf_max_rt = ntohl_unaligned(odata);
1223                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1224                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1225                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1226         #ifdef EXT_CER_ID
1227                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1228                                         sizeof(struct dhcpv6_cer_id)) {
1229                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1230                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1231                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1232                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1233         #endif
1234                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1235                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1236                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1237                                 size_t mape_len;
1238                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1239                                 if (mape_len == 0)
1240                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1241                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1242                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1243                         } else
1244                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1245 
1246                         if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1247                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1248                 }
1249         }
1250 
1251         // Bail out if fatal status code was received
1252         if (ret <= 0)
1253                 return ret;
1254 
1255         switch (orig) {
1256         case DHCPV6_MSG_REQUEST:
1257         case DHCPV6_MSG_REBIND:
1258         case DHCPV6_MSG_RENEW:
1259                 state_IAs = dhcpv6_calc_refresh_timers();
1260                 // In case there're no state IA entries
1261                 // keep sending request/renew/rebind messages
1262                 if (state_IAs == 0) {
1263                         ret = 0;
1264                         break;
1265                 }
1266 
1267                 if (orig == DHCPV6_MSG_REQUEST) {
1268                         // All server candidates can be cleared if not yet bound
1269                         if (!odhcp6c_is_bound())
1270                                 dhcpv6_clear_all_server_cand();
1271 
1272                         odhcp6c_clear_state(STATE_SERVER_ADDR);
1273                         odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1274                 } else if (orig == DHCPV6_MSG_RENEW) {
1275                         // Send further renews if T1 is not set and if
1276                         // there're IAs which were not in the Reply message
1277                         if (!t1 && state_IAs != updated_IAs) {
1278                                 if (updated_IAs)
1279                                         // Publish updates
1280                                         script_call("updated", 0, false);
1281 
1282                                 /*
1283                                  * RFC8415 states following in §18.2.10.1 :
1284                                  * Sends a Renew/Rebind if any of the IAs are not in the Reply
1285                                  * message, but as this likely indicates that the server that
1286                                  * responded does not support that IA type, sending immediately is
1287                                  * unlikely to produce a different result.  Therefore, the client
1288                                  * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1289                                  * wait for the normal retransmission time (as if the Reply message
1290                                  * had not been received).  The client continues to use other
1291                                  * bindings for which the server did return information
1292                                  */
1293                                 ret = -1;
1294                         }
1295                 } else if (orig == DHCPV6_MSG_REBIND) {
1296                         odhcp6c_clear_state(STATE_SERVER_ADDR);
1297                         odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1298 
1299                         // Send further rebinds if T1 and T2 is not set and if
1300                         // there're IAs which were not in the Reply message
1301                         if (!t1 && !t2 && state_IAs != updated_IAs) {
1302                                 if (updated_IAs)
1303                                         // Publish updates
1304                                         script_call("updated", 0, false);
1305 
1306                                 /*
1307                                  * RFC8415 states following in §18.2.10.1 :
1308                                  * Sends a Renew/Rebind if any of the IAs are not in the Reply
1309                                  * message, but as this likely indicates that the server that
1310                                  * responded does not support that IA type, sending immediately is
1311                                  * unlikely to produce a different result.  Therefore, the client
1312                                  * MUST rate-limit its transmissions (see Section 14.1) and MAY just
1313                                  * wait for the normal retransmission time (as if the Reply message
1314                                  * had not been received).  The client continues to use other
1315                                  * bindings for which the server did return information
1316                                  */
1317                                 ret = -1;
1318                         }
1319                 }
1320                 break;
1321 
1322         case DHCPV6_MSG_INFO_REQ:
1323                 // All server candidates can be cleared if not yet bound
1324                 if (!odhcp6c_is_bound())
1325                         dhcpv6_clear_all_server_cand();
1326 
1327                 t1 = refresh;
1328                 break;
1329 
1330         default:
1331                 break;
1332         }
1333 
1334         return ret;
1335 }
1336 
1337 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1338 {
1339         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1340         unsigned int updated_IAs = 0;
1341         uint32_t t1, t2;
1342         uint16_t otype, olen;
1343         uint8_t *odata;
1344         char buf[INET6_ADDRSTRLEN];
1345 
1346         t1 = ntohl(ia_hdr->t1);
1347         t2 = ntohl(ia_hdr->t2);
1348 
1349         if (t1 > t2 && t1 > 0 && t2 > 0)
1350                 return 0;
1351 
1352         syslog(LOG_INFO, "%s %04x T1 %d T2 %d", ntohs(ia_hdr->type) == DHCPV6_OPT_IA_PD ? "IA_PD" : "IA_NA", ntohl(ia_hdr->iaid), t1, t2);
1353 
1354         // Update address IA
1355         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1356                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1357                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1358 
1359                 entry.iaid = ia_hdr->iaid;
1360 
1361                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1362                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1363                         if (olen + 4U < sizeof(*prefix))
1364                                 continue;
1365 
1366                         entry.valid = ntohl(prefix->valid);
1367                         entry.preferred = ntohl(prefix->preferred);
1368 
1369                         if (entry.preferred > entry.valid)
1370                                 continue;
1371 
1372                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1373                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1374                         if (entry.t1 > entry.t2)
1375                                 entry.t1 = entry.t2;
1376 
1377                         entry.length = prefix->prefix;
1378                         entry.target = prefix->addr;
1379                         uint16_t stype, slen;
1380                         uint8_t *sdata;
1381 
1382                         // Parse PD-exclude
1383                         bool ok = true;
1384                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1385                                         odata + olen, stype, slen, sdata) {
1386                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1387                                         continue;
1388 
1389                                 uint8_t elen = sdata[0];
1390                                 if (elen > 64)
1391                                         elen = 64;
1392 
1393                                 if (entry.length < 32 || elen <= entry.length) {
1394                                         ok = false;
1395                                         continue;
1396                                 }
1397 
1398                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1399                                 if (slen <= bytes) {
1400                                         ok = false;
1401                                         continue;
1402                                 }
1403 
1404                                 uint32_t exclude = 0;
1405                                 do {
1406                                         exclude = exclude << 8 | sdata[bytes];
1407                                 } while (--bytes);
1408 
1409                                 exclude >>= 8 - ((elen - entry.length) % 8);
1410                                 exclude <<= 64 - elen;
1411 
1412                                 // Abusing router & priority fields for exclusion
1413                                 entry.router = entry.target;
1414                                 entry.router.s6_addr32[1] |= htonl(exclude);
1415                                 entry.priority = elen;
1416                         }
1417 
1418                         if (ok) {
1419                                 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1420                                         updated_IAs++;
1421 
1422                                 syslog(LOG_INFO, "%s/%d preferred %d valid %d",
1423                                        inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1424                                        entry.length, entry.preferred , entry.valid);
1425                         }
1426 
1427                         entry.priority = 0;
1428                         memset(&entry.router, 0, sizeof(entry.router));
1429                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1430                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1431                         if (olen + 4U < sizeof(*addr))
1432                                 continue;
1433 
1434                         entry.preferred = ntohl(addr->preferred);
1435                         entry.valid = ntohl(addr->valid);
1436 
1437                         if (entry.preferred > entry.valid)
1438                                 continue;
1439 
1440                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1441                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1442                         if (entry.t1 > entry.t2)
1443                                 entry.t1 = entry.t2;
1444 
1445                         entry.length = 128;
1446                         entry.target = addr->addr;
1447 
1448                         if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1449                                 updated_IAs++;
1450 
1451                         syslog(LOG_INFO, "%s preferred %d valid %d",
1452                                inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
1453                                entry.preferred , entry.valid);
1454                 }
1455         }
1456 
1457         return updated_IAs;
1458 }
1459 
1460 static unsigned int dhcpv6_calc_refresh_timers(void)
1461 {
1462         struct odhcp6c_entry *e;
1463         size_t ia_na_entries, ia_pd_entries, i;
1464         size_t invalid_entries = 0;
1465         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1466 
1467         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1468         ia_na_entries /= sizeof(*e);
1469 
1470         for (i = 0; i < ia_na_entries; i++) {
1471                 /* Exclude invalid IA_NA entries */
1472                 if (!e[i].valid) {
1473                         invalid_entries++;
1474                         continue;
1475                 }
1476 
1477                 if (e[i].t1 < l_t1)
1478                         l_t1 = e[i].t1;
1479 
1480                 if (e[i].t2 < l_t2)
1481                         l_t2 = e[i].t2;
1482 
1483                 if (e[i].valid > l_t3)
1484                         l_t3 = e[i].valid;
1485         }
1486 
1487         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1488         ia_pd_entries /= sizeof(*e);
1489 
1490         for (i = 0; i < ia_pd_entries; i++) {
1491                 /* Exclude invalid IA_PD entries */
1492                 if (!e[i].valid) {
1493                         invalid_entries++;
1494                         continue;
1495                 }
1496 
1497                 if (e[i].t1 < l_t1)
1498                         l_t1 = e[i].t1;
1499 
1500                 if (e[i].t2 < l_t2)
1501                         l_t2 = e[i].t2;
1502 
1503                 if (e[i].valid > l_t3)
1504                         l_t3 = e[i].valid;
1505         }
1506 
1507         if (ia_pd_entries + ia_na_entries - invalid_entries) {
1508                 t1 = l_t1;
1509                 t2 = l_t2;
1510                 t3 = l_t3;
1511 
1512                 syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
1513         }
1514 
1515         return (unsigned int)(ia_pd_entries + ia_na_entries);
1516 }
1517 
1518 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1519                 const void *status_msg, int len)
1520 {
1521         const char *src = status_msg;
1522         char buf[len + 3];
1523         char *dst = buf;
1524 
1525         if (len) {
1526                 *dst++ = '(';
1527                 while (len--) {
1528                         *dst = isprint((unsigned char)*src) ? *src : '?';
1529                         src++;
1530                         dst++;
1531                 }
1532                 *dst++ = ')';
1533         }
1534 
1535         *dst = 0;
1536 
1537         syslog(LOG_WARNING, "Server returned %s status '%s %s'",
1538                 scope, dhcpv6_status_code_to_str(code), buf);
1539 }
1540 
1541 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1542                 const uint16_t code, const void *status_msg, const int len,
1543                 int *ret)
1544 {
1545         dhcpv6_log_status_code(code, "message", status_msg, len);
1546 
1547         switch (code) {
1548         case DHCPV6_UnspecFail:
1549                 // Generic failure
1550                 *ret = 0;
1551                 break;
1552 
1553         case DHCPV6_UseMulticast:
1554                 switch(orig) {
1555                 case DHCPV6_MSG_REQUEST:
1556                 case DHCPV6_MSG_RENEW:
1557                 case DHCPV6_MSG_RELEASE:
1558                 case DHCPV6_MSG_DECLINE:
1559                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1560                         server_addr = in6addr_any;
1561                         *ret = 0;
1562                         break;
1563                 default:
1564                         break;
1565                 }
1566                 break;
1567 
1568         case DHCPV6_NoAddrsAvail:
1569         case DHCPV6_NoPrefixAvail:
1570                 if (orig == DHCPV6_MSG_REQUEST)
1571                         *ret = 0; // Failure
1572                 break;
1573 
1574         default:
1575                 break;
1576         }
1577 }
1578 
1579 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1580                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1581                 const void *status_msg, const int len,
1582                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1583 {
1584         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1585                 "IA_NA" : "IA_PD", status_msg, len);
1586 
1587         switch (code) {
1588         case DHCPV6_NoBinding:
1589                 switch (orig) {
1590                 case DHCPV6_MSG_RENEW:
1591                 case DHCPV6_MSG_REBIND:
1592                         if ((*ret > 0) && !handled_status_codes[code])
1593                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1594                         break;
1595 
1596                 default:
1597                         break;
1598                 }
1599                 break;
1600 
1601         default:
1602                 *ret = 0;
1603                 break;
1604         }
1605 }
1606 
1607 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1608 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1609 {
1610         size_t cand_len, i;
1611         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1612 
1613         // Remove identical duid server candidate
1614         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1615                 if (cand->duid_len == c[i].duid_len &&
1616                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1617                         free(c[i].ia_na);
1618                         free(c[i].ia_pd);
1619                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1620                         break;
1621                 }
1622         }
1623 
1624         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1625                 i < cand_len / sizeof(*c); ++i) {
1626                 if (c[i].preference < cand->preference)
1627                         break;
1628         }
1629 
1630         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1631                 free(cand->ia_na);
1632                 free(cand->ia_pd);
1633         }
1634 }
1635 
1636 static void dhcpv6_clear_all_server_cand(void)
1637 {
1638         size_t cand_len, i;
1639         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1640 
1641         // Server candidates need deep delete for IA_NA/IA_PD
1642         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1643                 free(c[i].ia_na);
1644                 free(c[i].ia_pd);
1645         }
1646         odhcp6c_clear_state(STATE_SERVER_CAND);
1647 }
1648 
1649 int dhcpv6_promote_server_cand(void)
1650 {
1651         size_t cand_len;
1652         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1653         uint16_t hdr[2];
1654         int ret = DHCPV6_STATELESS;
1655 
1656         // Clear lingering candidate state info
1657         odhcp6c_clear_state(STATE_SERVER_ID);
1658         odhcp6c_clear_state(STATE_IA_NA);
1659         odhcp6c_clear_state(STATE_IA_PD);
1660 
1661         if (!cand_len)
1662                 return -1;
1663 
1664         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1665                 na_mode = IA_MODE_NONE;
1666 
1667                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1668                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1669 
1670                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1671         }
1672 
1673         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1674         hdr[1] = htons(cand->duid_len);
1675         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1676         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1677         accept_reconfig = cand->wants_reconfigure;
1678 
1679         if (cand->ia_na_len) {
1680                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1681                 free(cand->ia_na);
1682                 if (na_mode != IA_MODE_NONE)
1683                         ret = DHCPV6_STATEFUL;
1684         }
1685 
1686         if (cand->ia_pd_len) {
1687                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1688                 free(cand->ia_pd);
1689                 if (pd_mode != IA_MODE_NONE)
1690                         ret = DHCPV6_STATEFUL;
1691         }
1692 
1693         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1694         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1695 
1696         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1697 
1698         return ret;
1699 }
1700 

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