Fix server candidate selection logic
[odhcp6c.git] / src / dhcpv6.c
1 /**
2  * Copyright (C) 2012-2013 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 <arpa/inet.h>
30 #include <netinet/in.h>
31
32 #include <net/if.h>
33 #include <net/ethernet.h>
34
35 #include "odhcp6c.h"
36 #include "md5.h"
37
38
39 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
40                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
41 #define DHCPV6_CLIENT_PORT 546
42 #define DHCPV6_SERVER_PORT 547
43 #define DHCPV6_DUID_LLADDR 3
44 #define DHCPV6_REQ_DELAY 1
45
46
47 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
48                 const uint8_t transaction[3], enum dhcpv6_msg type,
49                 const struct in6_addr *daddr);
50
51 static int dhcpv6_parse_ia(void *opt, void *end);
52
53 static int dhcpv6_calc_refresh_timers(void);
54 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
55                 const uint16_t code, const void *status_msg, const int len,
56                 int *ret);
57 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
58                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
59                 const void *status_msg, const int len,
60                 bool handled_status_codes[_DHCPV6_Status_Max],
61                 int *ret);
62 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
63 static void dhcpv6_clear_all_server_cand(void);
64
65 static reply_handler dhcpv6_handle_reply;
66 static reply_handler dhcpv6_handle_advert;
67 static reply_handler dhcpv6_handle_rebind_reply;
68 static reply_handler dhcpv6_handle_reconfigure;
69 static int dhcpv6_commit_advert(void);
70
71
72
73 // RFC 3315 - 5.5 Timeout and Delay values
74 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
75         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
76                         dhcpv6_handle_reconfigure, NULL},
77         [DHCPV6_MSG_SOLICIT] = {true, 1, 3600, 0, "SOLICIT",
78                         dhcpv6_handle_advert, dhcpv6_commit_advert},
79         [DHCPV6_MSG_REQUEST] = {true, 1, 30, 10, "REQUEST",
80                         dhcpv6_handle_reply, NULL},
81         [DHCPV6_MSG_RENEW] = {false, 10, 600, 0, "RENEW",
82                         dhcpv6_handle_reply, NULL},
83         [DHCPV6_MSG_REBIND] = {false, 10, 600, 0, "REBIND",
84                         dhcpv6_handle_rebind_reply, NULL},
85         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
86         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
87         [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, 0, "INFOREQ",
88                         dhcpv6_handle_reply, NULL},
89 };
90
91
92 // Sockets
93 static int sock = -1;
94 static int ifindex = -1;
95 static int64_t t1 = 0, t2 = 0, t3 = 0;
96
97 // IA states
98 static int request_prefix = -1;
99 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
100 static bool accept_reconfig = false;
101 // Server unicast address
102 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
103
104 // Reconfigure key
105 static uint8_t reconf_key[16];
106
107
108 int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
109 {
110         request_prefix = request_pd;
111         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
112
113         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
114         if (sock < 0)
115                 return -1;
116
117         // Detect interface
118         struct ifreq ifr;
119         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
120         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
121                 return -1;
122         ifindex = ifr.ifr_ifindex;
123
124         // Create client DUID
125         size_t client_id_len;
126         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
127         if (client_id_len == 0) {
128                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
129                                 DHCPV6_DUID_LLADDR, 0, 1};
130
131                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
132                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
133
134                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
135                 struct ifreq ifs[100], *ifp, *ifend;
136                 struct ifconf ifc;
137                 ifc.ifc_req = ifs;
138                 ifc.ifc_len = sizeof(ifs);
139
140                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
141                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
142                         // If our interface doesn't have an address...
143                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
144                         for (ifp = ifc.ifc_req; ifp < ifend &&
145                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
146                                 memcpy(ifr.ifr_name, ifp->ifr_name,
147                                                 sizeof(ifr.ifr_name));
148                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
149                                         continue;
150
151                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
152                                                 ETHER_ADDR_LEN);
153                         }
154                 }
155
156                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
157         }
158
159         // Create ORO
160         uint16_t oro[] = {
161                         htons(DHCPV6_OPT_SIP_SERVER_D),
162                         htons(DHCPV6_OPT_SIP_SERVER_A),
163                         htons(DHCPV6_OPT_DNS_SERVERS),
164                         htons(DHCPV6_OPT_DNS_DOMAIN),
165                         htons(DHCPV6_OPT_UNICAST),
166                         htons(DHCPV6_OPT_NTP_SERVER),
167                         htons(DHCPV6_OPT_AFTR_NAME),
168                         htons(DHCPV6_OPT_PD_EXCLUDE),
169 #ifdef EXT_PREFIX_CLASS
170                         htons(DHCPV6_OPT_PREFIX_CLASS),
171 #endif
172         };
173         odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
174
175         // Configure IPv6-options
176         int val = 1;
177         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
178         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
179         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
180         val = 0;
181         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
182         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
183
184         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
185                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
186         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
187                 return -1;
188
189         return 0;
190 }
191
192
193 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
194 {
195         na_mode = na;
196         pd_mode = pd;
197 }
198
199
200 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
201 {
202         // Build FQDN
203         char fqdn_buf[256];
204         gethostname(fqdn_buf, sizeof(fqdn_buf));
205         struct {
206                 uint16_t type;
207                 uint16_t len;
208                 uint8_t flags;
209                 uint8_t data[256];
210         } fqdn;
211         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
212                         sizeof(fqdn.data), NULL, NULL);
213         fqdn.type = htons(DHCPV6_OPT_FQDN);
214         fqdn.len = htons(fqdn_len - 4);
215         fqdn.flags = 0;
216
217
218         // Build Client ID
219         size_t cl_id_len;
220         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
221
222         // Get Server ID
223         size_t srv_id_len;
224         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
225
226         // Build IA_PDs
227         size_t ia_pd_entries, ia_pd_len = 0;
228         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
229         ia_pd_entries /= sizeof(*e);
230         struct dhcpv6_ia_hdr hdr_ia_pd = {
231                 htons(DHCPV6_OPT_IA_PD),
232                 htons(sizeof(hdr_ia_pd) - 4),
233                 1, 0, 0
234         };
235
236
237         uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
238         for (size_t i = 0; i < ia_pd_entries; ++i) {
239                 uint8_t ex_len = 0;
240                 if (e[i].priority > 0)
241                         ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
242
243                 struct dhcpv6_ia_prefix p = {
244                         .type = htons(DHCPV6_OPT_IA_PREFIX),
245                         .len = htons(sizeof(p) - 4U + ex_len),
246                         .prefix = e[i].length,
247                         .addr = e[i].target
248                 };
249
250                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
251                 ia_pd_len += sizeof(p);
252
253                 if (ex_len) {
254                         ia_pd[ia_pd_len++] = 0;
255                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
256                         ia_pd[ia_pd_len++] = 0;
257                         ia_pd[ia_pd_len++] = ex_len - 4;
258                         ia_pd[ia_pd_len++] = e[i].priority;
259
260                         uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
261                         excl >>= (64 - e[i].priority);
262                         excl <<= 8 - ((e[i].priority - e[i].length) % 8);
263
264                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
265                                 ia_pd[ia_pd_len + i] = excl & 0xff;
266                         ia_pd_len += ex_len - 5;
267                 }
268         }
269
270         struct dhcpv6_ia_prefix pref = {
271                 .type = htons(DHCPV6_OPT_IA_PREFIX),
272                 .len = htons(25), .prefix = request_prefix
273         };
274         if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
275                 ia_pd = (uint8_t*)&pref;
276                 ia_pd_len = sizeof(pref);
277         }
278         hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
279
280         // Build IA_NAs
281         size_t ia_na_entries, ia_na_len = 0;
282         void *ia_na = NULL;
283         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
284         ia_na_entries /= sizeof(*e);
285
286         struct dhcpv6_ia_hdr hdr_ia_na = {
287                 htons(DHCPV6_OPT_IA_NA),
288                 htons(sizeof(hdr_ia_na) - 4),
289                 1, 0, 0
290         };
291
292         struct dhcpv6_ia_addr pa[ia_na_entries];
293         for (size_t i = 0; i < ia_na_entries; ++i) {
294                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
295                 pa[i].len = htons(sizeof(pa[i]) - 4U);
296                 pa[i].addr = e[i].target;
297                 pa[i].preferred = 0;
298                 pa[i].valid = 0;
299         }
300
301         ia_na = pa;
302         ia_na_len = sizeof(pa);
303         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
304
305         // Reconfigure Accept
306         struct {
307                 uint16_t type;
308                 uint16_t length;
309         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
310
311         // Request Information Refresh
312         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
313
314         // Prepare Header
315         size_t oro_len;
316         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
317         struct {
318                 uint8_t type;
319                 uint8_t trid[3];
320                 uint16_t elapsed_type;
321                 uint16_t elapsed_len;
322                 uint16_t elapsed_value;
323                 uint16_t oro_type;
324                 uint16_t oro_len;
325         } hdr = {
326                 type, {trid[0], trid[1], trid[2]},
327                 htons(DHCPV6_OPT_ELAPSED), htons(2),
328                         htons((ecs > 0xffff) ? 0xffff : ecs),
329                 htons(DHCPV6_OPT_ORO), htons(oro_len),
330         };
331
332         struct iovec iov[] = {
333                 {&hdr, sizeof(hdr)},
334                 {oro, oro_len},
335                 {&oro_refresh, 0},
336                 {cl_id, cl_id_len},
337                 {srv_id, srv_id_len},
338                 {&reconf_accept, sizeof(reconf_accept)},
339                 {&fqdn, fqdn_len},
340                 {&hdr_ia_na, sizeof(hdr_ia_na)},
341                 {ia_na, ia_na_len},
342                 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
343                 {ia_pd, ia_pd_len},
344         };
345
346         size_t cnt = ARRAY_SIZE(iov);
347         if (type == DHCPV6_MSG_INFO_REQ) {
348                 cnt = 5;
349                 iov[2].iov_len = sizeof(oro_refresh);
350                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
351         } else if (!request_prefix) {
352                 cnt = 9;
353         }
354
355         // Disable IAs if not used
356         if (type != DHCPV6_MSG_SOLICIT) {
357                 iov[5].iov_len = 0;
358                 if (ia_na_len == 0)
359                         iov[7].iov_len = 0;
360                 if (ia_pd_len == 0)
361                         iov[9].iov_len = 0;
362         }
363
364         if (na_mode == IA_MODE_NONE)
365                 iov[7].iov_len = 0;
366
367         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
368                 0, ALL_DHCPV6_RELAYS, ifindex};
369         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
370
371         switch (type) {
372         case DHCPV6_MSG_REQUEST:
373         case DHCPV6_MSG_RENEW:
374         case DHCPV6_MSG_RELEASE:
375         case DHCPV6_MSG_DECLINE:
376                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
377                         odhcp6c_addr_in_scope(&server_addr)) {
378                         srv.sin6_addr = server_addr;
379                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
380                                 srv.sin6_scope_id = 0;
381                 }
382                 break;
383         default:
384                 break;
385         }
386
387         if (sendmsg(sock, &msg, 0) < 0) {
388                 char in6_str[INET6_ADDRSTRLEN];
389
390                 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
391                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
392                                 in6_str, sizeof(in6_str)), strerror(errno));
393         }
394 }
395
396
397 static int64_t dhcpv6_rand_delay(int64_t time)
398 {
399         int random;
400         odhcp6c_random(&random, sizeof(random));
401         return (time * ((int64_t)random % 1000LL)) / 10000LL;
402 }
403
404
405 int dhcpv6_request(enum dhcpv6_msg type)
406 {
407         uint8_t rc = 0;
408         uint64_t timeout = UINT32_MAX;
409         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
410
411         if (retx->delay) {
412                 struct timespec ts = {0, 0};
413                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
414                 nanosleep(&ts, NULL);
415         }
416
417         if (type == DHCPV6_MSG_UNKNOWN)
418                 timeout = t1;
419         else if (type == DHCPV6_MSG_RENEW)
420                 timeout = (t2 > t1) ? t2 - t1 : 0;
421         else if (type == DHCPV6_MSG_REBIND)
422                 timeout = (t3 > t2) ? t3 - t2 : 0;
423
424         if (timeout == 0)
425                 return -1;
426
427         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
428                         retx->name, (unsigned long long)timeout, retx->max_rc);
429
430         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
431
432         // Generate transaction ID
433         uint8_t trid[3] = {0, 0, 0};
434         if (type != DHCPV6_MSG_UNKNOWN)
435                 odhcp6c_random(trid, sizeof(trid));
436         ssize_t len = -1;
437         int64_t rto = 0;
438
439         do {
440                 if (rto == 0) {
441                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
442
443                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
444                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
445                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
446
447                         rto = (retx->init_timeo * 1000 + delay);
448                 }
449                 else
450                         rto = (2 * rto + dhcpv6_rand_delay(rto));
451
452                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
453                         rto = retx->max_timeo * 1000 +
454                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
455
456                 // Calculate end for this round and elapsed time
457                 uint64_t round_end = round_start + rto;
458                 elapsed = round_start - start;
459
460                 // Don't wait too long
461                 if (round_end - start > timeout * 1000)
462                         round_end = timeout * 1000 + start;
463
464                 // Built and send package
465                 if (type != DHCPV6_MSG_UNKNOWN) {
466                         if (type != DHCPV6_MSG_SOLICIT)
467                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
468                                                 retx->name, (unsigned long long)elapsed, rc);
469                         dhcpv6_send(type, trid, elapsed / 10);
470                         rc++;
471                 }
472
473                 // Receive rounds
474                 for (; len < 0 && (round_start < round_end);
475                                 round_start = odhcp6c_get_milli_time()) {
476                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
477                         struct iovec iov = {buf, sizeof(buf)};
478                         struct msghdr msg = {NULL, 0, &iov, 1,
479                                         cmsg_buf, sizeof(cmsg_buf), 0};
480                         struct in6_pktinfo *pktinfo = NULL;
481
482                         // Check for pending signal
483                         if (odhcp6c_signal_process())
484                                 return -1;
485
486                         // Set timeout for receiving
487                         uint64_t t = round_end - round_start;
488                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
489                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
490                                         &timeout, sizeof(timeout));
491
492                         // Receive cycle
493                         len = recvmsg(sock, &msg, 0);
494                         if (len < 0)
495                                 continue;
496
497                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
498                                 ch = CMSG_NXTHDR(&msg, ch)) {
499                                 if (ch->cmsg_level == SOL_IPV6 &&
500                                         ch->cmsg_type == IPV6_PKTINFO) {
501                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
502                                         break;
503                                 }
504                         }
505
506                         if (pktinfo == NULL) {
507                                 len = -1;
508                                 continue;
509                         }
510
511                         if (!dhcpv6_response_is_valid(buf, len, trid,
512                                                         type, &pktinfo->ipi6_addr)) {
513                                 len = -1;
514                                 continue;
515                         }
516
517                         uint8_t *opt = &buf[4];
518                         uint8_t *opt_end = opt + len - 4;
519
520                         round_start = odhcp6c_get_milli_time();
521                         elapsed = round_start - start;
522                         syslog(LOG_NOTICE, "Got a valid reply after "
523                                         "%llums", (unsigned long long)elapsed);
524
525                         if (retx->handler_reply)
526                                 len = retx->handler_reply(type, rc, opt, opt_end);
527
528                         if (len > 0 && round_end - round_start > 1000)
529                                 round_end = 1000 + round_start;
530                 }
531
532                 // Allow
533                 if (retx->handler_finish)
534                         len = retx->handler_finish();
535         } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
536
537         return len;
538 }
539
540 // Message validation checks according to RFC3315 chapter 15
541 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
542                 const uint8_t transaction[3], enum dhcpv6_msg type,
543                 const struct in6_addr *daddr)
544 {
545         const struct dhcpv6_header *rep = buf;
546         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
547                         transaction, sizeof(rep->tr_id)))
548                 return false; // Invalid reply
549
550         if (type == DHCPV6_MSG_SOLICIT) {
551                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
552                                 rep->msg_type != DHCPV6_MSG_REPLY)
553                         return false;
554         } else if (type == DHCPV6_MSG_UNKNOWN) {
555                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
556                         return false;
557         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
558                 return false;
559         }
560
561         uint8_t *end = ((uint8_t*)buf) + len, *odata,
562                 rcmsg = DHCPV6_MSG_UNKNOWN;
563         uint16_t otype, olen;
564         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
565                 ia_present = false, options_valid = true;
566
567         size_t client_id_len, server_id_len;
568         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
569         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
570
571         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
572                 if (otype == DHCPV6_OPT_CLIENTID) {
573                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
574                                         &odata[-4], client_id, client_id_len);
575                 } else if (otype == DHCPV6_OPT_SERVERID) {
576                         if (server_id_len)
577                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
578                                                 &odata[-4], server_id, server_id_len);
579                         else
580                                 serverid_ok = true;
581                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
582                                 sizeof(struct dhcpv6_auth_reconfigure)) {
583                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
584                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
585                                 continue;
586
587                         md5_state_t md5;
588                         uint8_t serverhash[16], secretbytes[16], hash[16];
589                         memcpy(serverhash, r->key, sizeof(serverhash));
590                         memset(r->key, 0, sizeof(r->key));
591                         memcpy(secretbytes, reconf_key, sizeof(secretbytes));
592
593                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
594                                 secretbytes[i] ^= 0x36;
595
596                         md5_init(&md5);
597                         md5_append(&md5, secretbytes, sizeof(secretbytes));
598                         md5_append(&md5, buf, len);
599                         md5_finish(&md5, hash);
600
601                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
602                                 secretbytes[i] ^= 0x36;
603                                 secretbytes[i] ^= 0x5c;
604                         }
605
606                         md5_init(&md5);
607                         md5_append(&md5, secretbytes, sizeof(secretbytes));
608                         md5_append(&md5, hash, 16);
609                         md5_finish(&md5, hash);
610
611                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
612                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
613                         rcmsg = odata[0];
614                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
615                         ia_present = true;
616                         if (olen < sizeof(struct dhcpv6_ia_hdr))
617                                 options_valid = false;
618                 }
619                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
620                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
621                         // Options are not allowed on global level
622                         options_valid = false;
623                 }
624         }
625
626         if (!options_valid)
627                 return false;
628
629         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
630                 return false;
631
632         if (rep->msg_type == DHCPV6_MSG_RECONF) {
633                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
634                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
635                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
636                         return false;
637         }
638
639         return clientid_ok && serverid_ok;
640 }
641
642
643 int dhcpv6_poll_reconfigure(void)
644 {
645         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
646         if (ret != -1)
647                 ret = dhcpv6_request(ret);
648
649         return ret;
650 }
651
652
653 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
654                 const void *opt, const void *end)
655 {
656         uint16_t otype, olen;
657         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
658         dhcpv6_for_each_option(opt, end, otype, olen, odata)
659                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
660                                 odata[0] == DHCPV6_MSG_RENEW ||
661                                 odata[0] == DHCPV6_MSG_INFO_REQ))
662                         msg = odata[0];
663
664         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
665         return msg;
666 }
667
668
669 // Collect all advertised servers
670 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
671                 const void *opt, const void *end)
672 {
673         uint16_t olen, otype;
674         uint8_t *odata, pref = 0;
675         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
676                                         IN6ADDR_ANY_INIT, NULL, NULL, 0, 0};
677         bool have_na = false;
678         int have_pd = 0;
679
680         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
681                 if (orig == DHCPV6_MSG_SOLICIT &&
682                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
683                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
684                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
685                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
686                 }
687
688                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
689                         memcpy(cand.duid, odata, olen);
690                         cand.duid_len = olen;
691                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
692                         int error = ((int)odata[0] << 8 | (int)odata[1]);
693
694                         switch (error) {
695                         case DHCPV6_NoPrefixAvail:
696                                 // Status code on global level
697                                 if (pd_mode == IA_MODE_FORCE)
698                                         return -1;
699                                 cand.preference -= 2000;
700                                 break;
701
702                         case DHCPV6_NoAddrsAvail:
703                                 // Status code on global level
704                                 if (na_mode == IA_MODE_FORCE)
705                                         return -1;
706                                 break;
707
708                         default :
709                                 break;
710                         }
711                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
712                                 cand.preference >= 0) {
713                         cand.preference = pref = odata[0];
714                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
715                         cand.server_addr = *(struct in6_addr *)odata;
716                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
717                         cand.wants_reconfigure = true;
718                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
719                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
720                         uint8_t *oend = odata + olen, *d;
721                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
722                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
723                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
724                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
725                                         have_pd = p->prefix;
726                                 }
727                         }
728                 } else if (otype == DHCPV6_OPT_IA_NA) {
729                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
730                         uint8_t *oend = odata + olen, *d;
731                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
732                                 if (otype == DHCPV6_OPT_IA_ADDR)
733                                         have_na = true;
734                 }
735         }
736
737         if ((!have_na && na_mode == IA_MODE_FORCE) ||
738                         (!have_pd && pd_mode == IA_MODE_FORCE))
739                 return -1;
740
741         if (na_mode != IA_MODE_NONE && !have_na) {
742                 cand.has_noaddravail = true;
743                 cand.preference -= 1000;
744         }
745
746         if (pd_mode != IA_MODE_NONE) {
747                 if (have_pd)
748                         cand.preference += 2000 + (128 - have_pd);
749                 else
750                         cand.preference -= 2000;
751         }
752
753         if (cand.duid_len > 0) {
754                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
755                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
756                 dhcpv6_add_server_cand(&cand);
757         }
758
759         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
760 }
761
762
763 static int dhcpv6_commit_advert(void)
764 {
765         return dhcpv6_promote_server_cand();
766 }
767
768
769 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
770                 const void *opt, const void *end)
771 {
772         dhcpv6_handle_advert(orig, rc, opt, end);
773         if (dhcpv6_commit_advert() < 0)
774                 return -1;
775
776         return dhcpv6_handle_reply(orig, rc, opt, end);
777 }
778
779
780 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
781                 const void *opt, const void *end)
782 {
783         uint8_t *odata;
784         uint16_t otype, olen;
785         uint32_t refresh = UINT32_MAX;
786         int ret = 1;
787         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
788
789         odhcp6c_expire();
790
791         if (orig == DHCPV6_MSG_UNKNOWN) {
792                 static time_t last_update = 0;
793                 time_t now = odhcp6c_get_milli_time() / 1000;
794
795                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
796                 last_update = now;
797
798                 t1 -= elapsed;
799                 t2 -= elapsed;
800                 t3 -= elapsed;
801
802                 if (t1 < 0)
803                         t1 = 0;
804
805                 if (t2 < 0)
806                         t2 = 0;
807
808                 if (t3 < 0)
809                         t3 = 0;
810         }
811
812         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
813                 // Delete NA and PD we have in the state from the Advert
814                 odhcp6c_clear_state(STATE_IA_NA);
815                 odhcp6c_clear_state(STATE_IA_PD);
816         }
817
818         if (opt) {
819                 odhcp6c_clear_state(STATE_DNS);
820                 odhcp6c_clear_state(STATE_SEARCH);
821                 odhcp6c_clear_state(STATE_SNTP_IP);
822                 odhcp6c_clear_state(STATE_SNTP_FQDN);
823                 odhcp6c_clear_state(STATE_SIP_IP);
824                 odhcp6c_clear_state(STATE_SIP_FQDN);
825                 odhcp6c_clear_state(STATE_AFTR_NAME);
826         }
827
828         // Parse and find all matching IAs
829         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
830                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
831                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
832                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
833
834                         // Test ID
835                         if (ia_hdr->iaid != 1)
836                                 continue;
837
838                         uint16_t code = DHCPV6_Success;
839                         uint16_t stype, slen;
840                         uint8_t *sdata;
841                         // Get and handle status code
842                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
843                                         stype, slen, sdata) {
844                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
845                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
846                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
847
848                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
849
850                                         if (code == DHCPV6_Success)
851                                                 continue;
852
853                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
854                                                 code, mdata, mlen, handled_status_codes, &ret);
855
856
857                                         if (ret > 0)
858                                                 return ret;
859                                         break;
860                                 }
861                         }
862
863                         if (code != DHCPV6_Success)
864                                 continue;
865
866                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
867                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
868                         server_addr = *(struct in6_addr *)odata;
869                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
870                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
871                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
872                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
873
874                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
875                 }
876                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
877                         if (olen % 16 == 0)
878                                 odhcp6c_add_state(STATE_DNS, odata, olen);
879                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
880                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
881                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
882                         uint16_t stype, slen;
883                         uint8_t *sdata;
884                         // Test status and bail if error
885                         dhcpv6_for_each_option(odata, odata + olen,
886                                         stype, slen, sdata) {
887                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
888                                                 stype == NTP_SRV_ADDR))
889                                         odhcp6c_add_state(STATE_SNTP_IP,
890                                                         sdata, slen);
891                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
892                                         odhcp6c_add_state(STATE_SNTP_FQDN,
893                                                         sdata, slen);
894                         }
895                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
896                         if (olen == 16)
897                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
898                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
899                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
900                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
901                         refresh = ntohl(*((uint32_t*)odata));
902                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
903                                 sizeof(struct dhcpv6_auth_reconfigure)) {
904                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
905                         if (r->protocol == 3 && r->algorithm == 1 &&
906                                         r->reconf_type == 1)
907                                 memcpy(reconf_key, r->key, sizeof(r->key));
908                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
909                         size_t cur_len;
910                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
911                         if (cur_len == 0)
912                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
913                 } else if (otype != DHCPV6_OPT_CLIENTID &&
914                                 otype != DHCPV6_OPT_SERVERID) {
915                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
916                                         &odata[-4], olen + 4);
917                 }
918         }
919
920         if (orig != DHCPV6_MSG_INFO_REQ) {
921                 // Update refresh timers if no fatal status code was received
922                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
923                         switch (orig) {
924                         case DHCPV6_MSG_RENEW:
925                                 // Send further renews if T1 is not set
926                                 if (!t1)
927                                         ret = -1;
928                                 break;
929                         case DHCPV6_MSG_REBIND:
930                                 // Send further rebinds if T1 and T2 is not set
931                                 if (!t1 && !t2)
932                                         ret = -1;
933                                 break;
934
935                         case DHCPV6_MSG_REQUEST:
936                                 // All server candidates can be cleared if not yet bound
937                                 if (!odhcp6c_is_bound())
938                                         dhcpv6_clear_all_server_cand();
939
940                         default :
941                                 break;
942                         }
943                 }
944         }
945         else if (ret > 0) {
946                 // All server candidates can be cleared if not yet bound
947                 if (!odhcp6c_is_bound())
948                         dhcpv6_clear_all_server_cand();
949
950                 t1 = refresh;
951         }
952
953         return ret;
954 }
955
956
957 static int dhcpv6_parse_ia(void *opt, void *end)
958 {
959         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
960         int parsed_ia = 0;
961         uint32_t t1, t2;
962         uint16_t otype, olen;
963         uint8_t *odata;
964
965         t1 = ntohl(ia_hdr->t1);
966         t2 = ntohl(ia_hdr->t2);
967
968         if (t1 > t2)
969                 return 0;
970
971         // Update address IA
972         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
973                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
974                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
975
976                 if (otype == DHCPV6_OPT_IA_PREFIX) {
977                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
978                         if (olen + 4U < sizeof(*prefix))
979                                 continue;
980
981                         entry.valid = ntohl(prefix->valid);
982                         entry.preferred = ntohl(prefix->preferred);
983
984                         if (entry.preferred > entry.valid)
985                                 continue;
986
987                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
988                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
989                         if (entry.t1 > entry.t2)
990                                 entry.t1 = entry.t2;
991
992                         entry.length = prefix->prefix;
993                         entry.target = prefix->addr;
994                         uint16_t stype, slen;
995                         uint8_t *sdata;
996
997 #ifdef EXT_PREFIX_CLASS
998                         // Find prefix class, if any
999                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1000                                         stype, slen, sdata)
1001                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1002                                         entry.class = sdata[0] << 8 | sdata[1];
1003 #endif
1004
1005                         // Parse PD-exclude
1006                         bool ok = true;
1007                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1008                                         odata + olen, stype, slen, sdata) {
1009                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1010                                         continue;
1011
1012                                 uint8_t elen = sdata[0];
1013                                 if (elen > 64)
1014                                         elen = 64;
1015
1016                                 if (elen <= 32 || elen <= entry.length) {
1017                                         ok = false;
1018                                         continue;
1019                                 }
1020
1021
1022                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1023                                 if (slen <= bytes) {
1024                                         ok = false;
1025                                         continue;
1026                                 }
1027
1028                                 uint32_t exclude = 0;
1029                                 do {
1030                                         exclude = exclude << 8 | sdata[bytes];
1031                                 } while (--bytes);
1032
1033                                 exclude >>= 8 - ((elen - entry.length) % 8);
1034                                 exclude <<= 64 - elen;
1035
1036                                 // Abusing router & priority fields for exclusion
1037                                 entry.router = entry.target;
1038                                 entry.router.s6_addr32[1] |= htonl(exclude);
1039                                 entry.priority = elen;
1040                         }
1041
1042                         if (ok) {
1043                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1044                                 parsed_ia++;
1045                         }
1046
1047                         entry.priority = 0;
1048                         memset(&entry.router, 0, sizeof(entry.router));
1049                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1050                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1051                         if (olen + 4U < sizeof(*addr))
1052                                 continue;
1053
1054                         entry.preferred = ntohl(addr->preferred);
1055                         entry.valid = ntohl(addr->valid);
1056
1057                         if (entry.preferred > entry.valid)
1058                                 continue;
1059
1060                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1061                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1062                         if (entry.t1 > entry.t2)
1063                                 entry.t1 = entry.t2;
1064
1065                         entry.length = 128;
1066                         entry.target = addr->addr;
1067
1068 #ifdef EXT_PREFIX_CLASS
1069                         uint16_t stype, slen;
1070                         uint8_t *sdata;
1071                         // Find prefix class, if any
1072                         dhcpv6_for_each_option(&addr[1], odata + olen,
1073                                         stype, slen, sdata)
1074                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1075                                         entry.class = sdata[0] << 8 | sdata[1];
1076 #endif
1077
1078                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1079                         parsed_ia++;
1080                 }
1081         }
1082         return parsed_ia;
1083 }
1084
1085
1086 static int dhcpv6_calc_refresh_timers(void)
1087 {
1088         struct odhcp6c_entry *e;
1089         size_t ia_na_entries, ia_pd_entries, i;
1090         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1091
1092         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1093         ia_na_entries /= sizeof(*e);
1094         for (i = 0; i < ia_na_entries; i++) {
1095                 if (e[i].t1 < l_t1)
1096                         l_t1 = e[i].t1;
1097
1098                 if (e[i].t2 < l_t2)
1099                         l_t2 = e[i].t2;
1100
1101                 if (e[i].valid > l_t3)
1102                         l_t3 = e[i].valid;
1103         }
1104
1105         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1106         ia_pd_entries /= sizeof(*e);
1107         for (i = 0; i < ia_pd_entries; i++) {
1108                 if (e[i].t1 < l_t1)
1109                         l_t1 = e[i].t1;
1110
1111                 if (e[i].t2 < l_t2)
1112                         l_t2 = e[i].t2;
1113
1114                 if (e[i].valid > l_t3)
1115                         l_t3 = e[i].valid;
1116         }
1117
1118         if (ia_pd_entries || ia_na_entries) {
1119                 t1 = l_t1;
1120                 t2 = l_t2;
1121                 t3 = l_t3;
1122         }
1123
1124         return (int)(ia_pd_entries + ia_na_entries);
1125 }
1126
1127
1128 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1129                 const void *status_msg, const int len)
1130 {
1131         uint8_t buf[len + 3];
1132
1133         memset(buf, 0, sizeof(buf));
1134         if (len) {
1135                 buf[0] = '(';
1136                 memcpy(&buf[1], status_msg, len);
1137                 buf[len + 1] = ')';
1138         }
1139
1140         syslog(LOG_WARNING, "Server returned %s status %i %s",
1141                 scope, code, buf);
1142 }
1143
1144
1145 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1146                 const uint16_t code, const void *status_msg, const int len,
1147                 int *ret)
1148 {
1149         dhcpv6_log_status_code(code, "message", status_msg, len);
1150
1151         switch (code) {
1152         case DHCPV6_UnspecFail:
1153                 // Generic failure
1154                 *ret = 0;
1155                 break;
1156
1157         case DHCPV6_UseMulticast:
1158                 switch(orig) {
1159                 case DHCPV6_MSG_REQUEST:
1160                 case DHCPV6_MSG_RENEW:
1161                 case DHCPV6_MSG_RELEASE:
1162                 case DHCPV6_MSG_DECLINE:
1163                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1164                         server_addr = in6addr_any;
1165                         *ret = 0;
1166                         break;
1167                 default:
1168                         break;
1169                 }
1170                 break;
1171
1172         case DHCPV6_NoAddrsAvail:
1173         case DHCPV6_NoPrefixAvail:
1174                 if (orig == DHCPV6_MSG_REQUEST)
1175                         *ret = 0; // Failure
1176                 break;
1177
1178         default:
1179                 break;
1180         }
1181 }
1182
1183
1184 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1185                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1186                 const void *status_msg, const int len,
1187                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1188 {
1189         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1190                 "IA_NA" : "IA_PD", status_msg, len);
1191
1192         switch (code) {
1193         case DHCPV6_NoBinding:
1194                 switch (orig) {
1195                 case DHCPV6_MSG_RENEW:
1196                 case DHCPV6_MSG_REBIND:
1197                         if ((*ret > 0) && !handled_status_codes[code])
1198                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1199                         break;
1200
1201                 default:
1202                         break;
1203                 }
1204                 break;
1205
1206         case DHCPV6_NoAddrsAvail:
1207         case DHCPV6_NoPrefixAvail:
1208                 switch (orig) {
1209                 case DHCPV6_MSG_REQUEST:
1210                         if (*ret != 0)
1211                                 *ret = 0;
1212                         break;
1213                 default:
1214                         break;
1215                 }
1216                 break;
1217
1218         case DHCPV6_NotOnLink:
1219                 // TODO handle not onlink in case of confirm
1220                 break;
1221
1222         default:
1223                 break;
1224         }
1225 }
1226
1227 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1228 {
1229         size_t cand_len, i;
1230         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1231
1232         // Remove identical duid server candidate
1233         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1234                 if (cand->duid_len == c[i].duid_len &&
1235                         !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1236                         free(c[i].ia_na);
1237                         free(c[i].ia_pd);
1238                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1239                         break;
1240                 }
1241         }
1242
1243         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1244                 i < cand_len / sizeof(*c); ++i) {
1245                 if (c[i].preference < cand->preference)
1246                         break;
1247         }
1248
1249         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1250 }
1251
1252 static void dhcpv6_clear_all_server_cand(void)
1253 {
1254         size_t cand_len, i;
1255         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1256
1257         // Server candidates need deep delete for IA_NA/IA_PD
1258         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1259                 if (c[i].ia_na)
1260                         free(c[i].ia_na);
1261                 if (c[i].ia_pd)
1262                         free(c[i].ia_pd);
1263         }
1264         odhcp6c_clear_state(STATE_SERVER_CAND);
1265 }
1266
1267 int dhcpv6_promote_server_cand(void)
1268 {
1269         size_t cand_len;
1270         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1271         uint16_t hdr[2];
1272         int ret = DHCPV6_STATELESS;
1273
1274         // Clear lingering candidate state info
1275         odhcp6c_clear_state(STATE_SERVER_ID);
1276         odhcp6c_clear_state(STATE_IA_NA);
1277         odhcp6c_clear_state(STATE_IA_PD);
1278
1279         if (!cand_len)
1280                 return -1;
1281
1282         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1283                 na_mode = IA_MODE_NONE;
1284                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1285         }
1286
1287         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1288         hdr[1] = htons(cand->duid_len);
1289         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1290         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1291         accept_reconfig = cand->wants_reconfigure;
1292         if (cand->ia_na_len) {
1293                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1294                 free(cand->ia_na);
1295                 if (na_mode != IA_MODE_NONE)
1296                         ret = DHCPV6_STATEFUL;
1297         }
1298         if (cand->ia_pd_len) {
1299                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1300                 free(cand->ia_pd);
1301                 if (request_prefix)
1302                         ret = DHCPV6_STATEFUL;
1303         }
1304
1305         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1306
1307         return ret;
1308 }