Enable softwire-support by default
[odhcp6c.git] / src / dhcpv6.c
1 /**
2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License v2 as published by
6  * the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  *
13  */
14
15 #include <time.h>
16 #include <fcntl.h>
17 #include <errno.h>
18 #include <stdlib.h>
19 #include <signal.h>
20 #include <limits.h>
21 #include <resolv.h>
22 #include <string.h>
23 #include <unistd.h>
24 #include <syslog.h>
25 #include <stdbool.h>
26 #include <sys/time.h>
27 #include <sys/ioctl.h>
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30
31 #include <net/if.h>
32 #include <net/ethernet.h>
33
34 #include "odhcp6c.h"
35 #include "md5.h"
36
37
38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
40 #define DHCPV6_CLIENT_PORT 546
41 #define DHCPV6_SERVER_PORT 547
42 #define DHCPV6_DUID_LLADDR 3
43 #define DHCPV6_REQ_DELAY 1
44
45 #define DHCPV6_SOL_MAX_RT_MIN 60
46 #define DHCPV6_SOL_MAX_RT_MAX 86400
47 #define DHCPV6_INF_MAX_RT_MIN 60
48 #define DHCPV6_INF_MAX_RT_MAX 86400
49
50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
51                 const uint8_t transaction[3], enum dhcpv6_msg type,
52                 const struct in6_addr *daddr);
53
54 static int dhcpv6_parse_ia(void *opt, void *end);
55
56 static int dhcpv6_calc_refresh_timers(void);
57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
58                 const uint16_t code, const void *status_msg, const int len,
59                 int *ret);
60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
62                 const void *status_msg, const int len,
63                 bool handled_status_codes[_DHCPV6_Status_Max],
64                 int *ret);
65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
66 static void dhcpv6_clear_all_server_cand(void);
67
68 static reply_handler dhcpv6_handle_reply;
69 static reply_handler dhcpv6_handle_advert;
70 static reply_handler dhcpv6_handle_rebind_reply;
71 static reply_handler dhcpv6_handle_reconfigure;
72 static int dhcpv6_commit_advert(void);
73
74
75
76 // RFC 3315 - 5.5 Timeout and Delay values
77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
79                         dhcpv6_handle_reconfigure, NULL},
80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
83                         dhcpv6_handle_reply, NULL},
84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
85                         dhcpv6_handle_reply, NULL},
86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
87                         dhcpv6_handle_rebind_reply, NULL},
88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
91                         dhcpv6_handle_reply, NULL},
92 };
93
94
95 // Sockets
96 static int sock = -1;
97 static int ifindex = -1;
98 static int64_t t1 = 0, t2 = 0, t3 = 0;
99
100 // IA states
101 static int request_prefix = -1;
102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
103 static bool accept_reconfig = false;
104
105 // Reconfigure key
106 static uint8_t reconf_key[16];
107
108 // client options
109 static unsigned int client_options = 0;
110
111
112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
113 {
114         client_options = options;
115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
116
117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
118         if (sock < 0)
119                 return -1;
120
121         // Detect interface
122         struct ifreq ifr;
123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
125                 return -1;
126         ifindex = ifr.ifr_ifindex;
127
128         // Create client DUID
129         size_t client_id_len;
130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
131         if (client_id_len == 0) {
132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
133                                 DHCPV6_DUID_LLADDR, 0, 1};
134
135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
137
138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
139                 struct ifreq ifs[100], *ifp, *ifend;
140                 struct ifconf ifc;
141                 ifc.ifc_req = ifs;
142                 ifc.ifc_len = sizeof(ifs);
143
144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
146                         // If our interface doesn't have an address...
147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
148                         for (ifp = ifc.ifc_req; ifp < ifend &&
149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
151                                                 sizeof(ifr.ifr_name));
152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
153                                         continue;
154
155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
156                                                 ETHER_ADDR_LEN);
157                         }
158                 }
159
160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
161         }
162
163         // Create ORO
164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
165                 uint16_t oro[] = {
166                         htons(DHCPV6_OPT_SIP_SERVER_D),
167                         htons(DHCPV6_OPT_SIP_SERVER_A),
168                         htons(DHCPV6_OPT_DNS_SERVERS),
169                         htons(DHCPV6_OPT_DNS_DOMAIN),
170                         htons(DHCPV6_OPT_SNTP_SERVERS),
171                         htons(DHCPV6_OPT_NTP_SERVER),
172                         htons(DHCPV6_OPT_AFTR_NAME),
173                         htons(DHCPV6_OPT_PD_EXCLUDE),
174                         htons(DHCPV6_OPT_SOL_MAX_RT),
175                         htons(DHCPV6_OPT_INF_MAX_RT),
176 #ifdef EXT_PREFIX_CLASS
177                         htons(DHCPV6_OPT_PREFIX_CLASS),
178 #endif
179 #ifdef EXT_CER_ID
180                         htons(DHCPV6_OPT_CER_ID),
181 #endif
182                         htons(DHCPV6_OPT_S46_CONT_MAPE),
183                         htons(DHCPV6_OPT_S46_CONT_MAPT),
184                         htons(DHCPV6_OPT_S46_CONT_LW),
185                 };
186                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
187         }
188
189         // Configure IPv6-options
190         int val = 1;
191         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
192         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
193         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
194         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
195
196         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
197                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
198         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
199                 return -1;
200
201         return 0;
202 }
203
204 enum {
205         IOV_HDR=0,
206         IOV_ORO,
207         IOV_ORO_REFRESH,
208         IOV_CL_ID,
209         IOV_SRV_ID,
210         IOV_VENDOR_CLASS_HDR,
211         IOV_VENDOR_CLASS,
212         IOV_USER_CLASS_HDR,
213         IOV_USER_CLASS,
214         IOV_RECONF_ACCEPT,
215         IOV_FQDN,
216         IOV_HDR_IA_NA,
217         IOV_IA_NA,
218         IOV_IA_PD,
219         IOV_TOTAL
220 };
221
222 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
223 {
224         na_mode = na;
225         pd_mode = pd;
226 }
227
228 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
229 {
230         // Build FQDN
231         char fqdn_buf[256];
232         gethostname(fqdn_buf, sizeof(fqdn_buf));
233         struct {
234                 uint16_t type;
235                 uint16_t len;
236                 uint8_t flags;
237                 uint8_t data[256];
238         } fqdn;
239         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
240                         sizeof(fqdn.data), NULL, NULL);
241         fqdn.type = htons(DHCPV6_OPT_FQDN);
242         fqdn.len = htons(fqdn_len - 4);
243         fqdn.flags = 0;
244
245
246         // Build Client ID
247         size_t cl_id_len;
248         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
249
250         // Get Server ID
251         size_t srv_id_len;
252         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
253
254         // Build IA_PDs
255         size_t ia_pd_entries = 0, ia_pd_len = 0;
256         uint8_t *ia_pd;
257
258         if (type == DHCPV6_MSG_SOLICIT) {
259                 odhcp6c_clear_state(STATE_IA_PD);
260                 size_t n_prefixes;
261                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
262                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
263
264                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
265
266                 for (size_t i = 0; i < n_prefixes; i++) {
267                         struct dhcpv6_ia_hdr hdr_ia_pd = {
268                                 htons(DHCPV6_OPT_IA_PD),
269                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
270                                 request_prefixes[i].iaid, 0, 0
271                         };
272                         struct dhcpv6_ia_prefix pref = {
273                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
274                                 .len = htons(25), .prefix = request_prefixes[i].length
275                         };
276                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
277                         ia_pd_len += sizeof(hdr_ia_pd);
278                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
279                         ia_pd_len += sizeof(pref);
280                 }
281         } else {
282                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
283                 ia_pd_entries /= sizeof(*e);
284
285                 // we're too lazy to count our distinct IAIDs,
286                 // so just allocate maximally needed space
287                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
288                                         sizeof(struct dhcpv6_ia_hdr)));
289
290                 for (size_t i = 0; i < ia_pd_entries; ++i) {
291                         uint32_t iaid = e[i].iaid;
292
293                         // check if this is an unprocessed IAID and skip if not.
294                         int new_iaid = 1;
295                         for (int j = i-1; j >= 0; j--) {
296                                 if (e[j].iaid == iaid) {
297                                         new_iaid = 0;
298                                         break;
299                                 }
300                         }
301
302                         if (!new_iaid)
303                                 continue;
304
305                         // construct header
306                         struct dhcpv6_ia_hdr hdr_ia_pd = {
307                                 htons(DHCPV6_OPT_IA_PD),
308                                 htons(sizeof(hdr_ia_pd) - 4),
309                                 iaid, 0, 0
310                         };
311
312                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
313                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
314                         ia_pd_len += sizeof(hdr_ia_pd);
315
316                         for (size_t j = i; j < ia_pd_entries; j++) {
317                                 if (e[j].iaid != iaid)
318                                         continue;
319
320                                 uint8_t ex_len = 0;
321                                 if (e[j].priority > 0)
322                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
323
324                                 struct dhcpv6_ia_prefix p = {
325                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
326                                         .len = htons(sizeof(p) - 4U + ex_len),
327                                         .prefix = e[j].length,
328                                         .addr = e[j].target
329                                 };
330
331                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
332                                 ia_pd_len += sizeof(p);
333
334                                 if (ex_len) {
335                                         ia_pd[ia_pd_len++] = 0;
336                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
337                                         ia_pd[ia_pd_len++] = 0;
338                                         ia_pd[ia_pd_len++] = ex_len - 4;
339                                         ia_pd[ia_pd_len++] = e[j].priority;
340
341                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
342                                         excl >>= (64 - e[j].priority);
343                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
344
345                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
346                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
347                                         ia_pd_len += ex_len - 5;
348                                 }
349
350                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
351                         }
352                 }
353         }
354
355         if (ia_pd_entries > 0)
356                 request_prefix = 1;
357
358         // Build IA_NAs
359         size_t ia_na_entries, ia_na_len = 0;
360         void *ia_na = NULL;
361         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
362         ia_na_entries /= sizeof(*e);
363
364         struct dhcpv6_ia_hdr hdr_ia_na = {
365                 htons(DHCPV6_OPT_IA_NA),
366                 htons(sizeof(hdr_ia_na) - 4),
367                 htonl(1), 0, 0
368         };
369
370         struct dhcpv6_ia_addr pa[ia_na_entries];
371         for (size_t i = 0; i < ia_na_entries; ++i) {
372                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
373                 pa[i].len = htons(sizeof(pa[i]) - 4U);
374                 pa[i].addr = e[i].target;
375                 pa[i].preferred = 0;
376                 pa[i].valid = 0;
377         }
378
379         ia_na = pa;
380         ia_na_len = sizeof(pa);
381         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
382
383         // Reconfigure Accept
384         struct {
385                 uint16_t type;
386                 uint16_t length;
387         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
388
389         // Request Information Refresh
390         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
391
392         // Build vendor-class option
393         size_t vendor_class_len, user_class_len;
394         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
395         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
396
397         struct {
398                 uint16_t type;
399                 uint16_t length;
400         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
401
402         struct {
403                 uint16_t type;
404                 uint16_t length;
405         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
406
407         // Prepare Header
408         size_t oro_len;
409         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
410         struct {
411                 uint8_t type;
412                 uint8_t trid[3];
413                 uint16_t elapsed_type;
414                 uint16_t elapsed_len;
415                 uint16_t elapsed_value;
416                 uint16_t oro_type;
417                 uint16_t oro_len;
418         } hdr = {
419                 type, {trid[0], trid[1], trid[2]},
420                 htons(DHCPV6_OPT_ELAPSED), htons(2),
421                         htons((ecs > 0xffff) ? 0xffff : ecs),
422                 htons(DHCPV6_OPT_ORO), htons(oro_len),
423         };
424
425         struct iovec iov[IOV_TOTAL] = {
426                 [IOV_HDR] = {&hdr, sizeof(hdr)},
427                 [IOV_ORO] = {oro, oro_len},
428                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
429                 [IOV_CL_ID] = {cl_id, cl_id_len},
430                 [IOV_SRV_ID] = {srv_id, srv_id_len},
431                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
432                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
433                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
434                 [IOV_USER_CLASS] = {user_class, user_class_len},
435                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
436                 [IOV_FQDN] = {&fqdn, fqdn_len},
437                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
438                 [IOV_IA_NA] = {ia_na, ia_na_len},
439                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
440         };
441
442         size_t cnt = IOV_TOTAL;
443         if (type == DHCPV6_MSG_INFO_REQ) {
444                 cnt = 9;
445                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
446                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
447         } else if (!request_prefix) {
448                 cnt = 13;
449         }
450
451         // Disable IAs if not used
452         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
453                 iov[IOV_HDR_IA_NA].iov_len = 0;
454
455         if (na_mode == IA_MODE_NONE)
456                 iov[IOV_HDR_IA_NA].iov_len = 0;
457
458         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
459                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
460                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
461
462         if (!(client_options & DHCPV6_CLIENT_FQDN))
463                 iov[IOV_FQDN].iov_len = 0;
464
465         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
466                 0, ALL_DHCPV6_RELAYS, ifindex};
467         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
468
469         sendmsg(sock, &msg, 0);
470 }
471
472
473 static int64_t dhcpv6_rand_delay(int64_t time)
474 {
475         int random;
476         odhcp6c_random(&random, sizeof(random));
477         return (time * ((int64_t)random % 1000LL)) / 10000LL;
478 }
479
480
481 int dhcpv6_request(enum dhcpv6_msg type)
482 {
483         uint8_t rc = 0;
484         uint64_t timeout = UINT32_MAX;
485         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
486
487         if (retx->delay) {
488                 struct timespec ts = {0, 0};
489                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
490                 nanosleep(&ts, NULL);
491         }
492
493         if (type == DHCPV6_MSG_UNKNOWN)
494                 timeout = t1;
495         else if (type == DHCPV6_MSG_RENEW)
496                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
497         else if (type == DHCPV6_MSG_REBIND)
498                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
499
500         if (timeout == 0)
501                 return -1;
502
503         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
504                         retx->name, (unsigned long long)timeout, retx->max_rc);
505
506         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
507
508         // Generate transaction ID
509         uint8_t trid[3] = {0, 0, 0};
510         if (type != DHCPV6_MSG_UNKNOWN)
511                 odhcp6c_random(trid, sizeof(trid));
512         ssize_t len = -1;
513         int64_t rto = 0;
514
515         do {
516                 if (rto == 0) {
517                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
518
519                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
520                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
521                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
522
523                         rto = (retx->init_timeo * 1000 + delay);
524                 }
525                 else
526                         rto = (2 * rto + dhcpv6_rand_delay(rto));
527
528                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
529                         rto = retx->max_timeo * 1000 +
530                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
531
532                 // Calculate end for this round and elapsed time
533                 uint64_t round_end = round_start + rto;
534                 elapsed = round_start - start;
535
536                 // Don't wait too long if timeout differs from infinite
537                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
538                         round_end = timeout * 1000 + start;
539
540                 // Built and send package
541                 if (type != DHCPV6_MSG_UNKNOWN) {
542                         if (type != DHCPV6_MSG_SOLICIT)
543                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
544                                                 retx->name, (unsigned long long)elapsed, rc);
545                         dhcpv6_send(type, trid, elapsed / 10);
546                         rc++;
547                 }
548
549                 // Receive rounds
550                 for (; len < 0 && (round_start < round_end);
551                                 round_start = odhcp6c_get_milli_time()) {
552                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
553                         struct iovec iov = {buf, sizeof(buf)};
554                         struct msghdr msg = {NULL, 0, &iov, 1,
555                                         cmsg_buf, sizeof(cmsg_buf), 0};
556                         struct in6_pktinfo *pktinfo = NULL;
557
558                         // Check for pending signal
559                         if (odhcp6c_signal_process())
560                                 return -1;
561
562                         // Set timeout for receiving
563                         uint64_t t = round_end - round_start;
564                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
565                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
566                                         &tv, sizeof(tv));
567
568                         // Receive cycle
569                         len = recvmsg(sock, &msg, 0);
570                         if (len < 0)
571                                 continue;
572
573                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
574                                 ch = CMSG_NXTHDR(&msg, ch)) {
575                                 if (ch->cmsg_level == SOL_IPV6 &&
576                                         ch->cmsg_type == IPV6_PKTINFO) {
577                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
578                                         break;
579                                 }
580                         }
581
582                         if (pktinfo == NULL) {
583                                 len = -1;
584                                 continue;
585                         }
586
587                         if (!dhcpv6_response_is_valid(buf, len, trid,
588                                                         type, &pktinfo->ipi6_addr)) {
589                                 len = -1;
590                                 continue;
591                         }
592
593                         uint8_t *opt = &buf[4];
594                         uint8_t *opt_end = opt + len - 4;
595
596                         round_start = odhcp6c_get_milli_time();
597                         elapsed = round_start - start;
598                         syslog(LOG_NOTICE, "Got a valid reply after "
599                                         "%llums", (unsigned long long)elapsed);
600
601                         if (retx->handler_reply)
602                                 len = retx->handler_reply(type, rc, opt, opt_end);
603
604                         if (len > 0 && round_end - round_start > 1000)
605                                 round_end = 1000 + round_start;
606                 }
607
608                 // Allow
609                 if (retx->handler_finish)
610                         len = retx->handler_finish();
611         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) && 
612                         (!retx->max_rc || rc < retx->max_rc));
613         return len;
614 }
615
616 // Message validation checks according to RFC3315 chapter 15
617 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
618                 const uint8_t transaction[3], enum dhcpv6_msg type,
619                 const struct in6_addr *daddr)
620 {
621         const struct dhcpv6_header *rep = buf;
622         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
623                         transaction, sizeof(rep->tr_id)))
624                 return false; // Invalid reply
625
626         if (type == DHCPV6_MSG_SOLICIT) {
627                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
628                                 rep->msg_type != DHCPV6_MSG_REPLY)
629                         return false;
630         } else if (type == DHCPV6_MSG_UNKNOWN) {
631                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
632                         return false;
633         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
634                 return false;
635         }
636
637         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
638                 rcmsg = DHCPV6_MSG_UNKNOWN;
639         uint16_t otype, olen = UINT16_MAX;
640         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
641                 ia_present = false, options_valid = true;
642
643         size_t client_id_len, server_id_len;
644         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
645         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
646
647         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
648                 if (otype == DHCPV6_OPT_CLIENTID) {
649                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
650                                         &odata[-4], client_id, client_id_len);
651                 } else if (otype == DHCPV6_OPT_SERVERID) {
652                         if (server_id_len)
653                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
654                                                 &odata[-4], server_id, server_id_len);
655                         else
656                                 serverid_ok = true;
657                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
658                                 sizeof(struct dhcpv6_auth_reconfigure)) {
659                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
660                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
661                                 continue;
662
663                         md5_ctx_t md5;
664                         uint8_t serverhash[16], secretbytes[64], hash[16];
665                         memcpy(serverhash, r->key, sizeof(serverhash));
666                         memset(r->key, 0, sizeof(r->key));
667
668                         memset(secretbytes, 0, sizeof(secretbytes));
669                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
670
671                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
672                                 secretbytes[i] ^= 0x36;
673
674                         md5_begin(&md5);
675                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
676                         md5_hash(buf, len, &md5);
677                         md5_end(hash, &md5);
678
679                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
680                                 secretbytes[i] ^= 0x36;
681                                 secretbytes[i] ^= 0x5c;
682                         }
683
684                         md5_begin(&md5);
685                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
686                         md5_hash(hash, 16, &md5);
687                         md5_end(hash, &md5);
688
689                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
690                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
691                         rcmsg = odata[0];
692                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
693                         ia_present = true;
694                         if (olen < sizeof(struct dhcpv6_ia_hdr))
695                                 options_valid = false;
696                 }
697                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
698                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
699                         // Options are not allowed on global level
700                         options_valid = false;
701                 }
702         }
703
704         if (!options_valid || ((odata + olen) > end))
705                 return false;
706
707         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
708                 return false;
709
710         if (rep->msg_type == DHCPV6_MSG_RECONF) {
711                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
712                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
713                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
714                         return false;
715         }
716
717         return clientid_ok && serverid_ok;
718 }
719
720
721 int dhcpv6_poll_reconfigure(void)
722 {
723         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
724         if (ret != -1)
725                 ret = dhcpv6_request(ret);
726
727         return ret;
728 }
729
730
731 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
732                 const void *opt, const void *end)
733 {
734         uint16_t otype, olen;
735         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
736         dhcpv6_for_each_option(opt, end, otype, olen, odata)
737                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
738                                 odata[0] == DHCPV6_MSG_RENEW ||
739                                 odata[0] == DHCPV6_MSG_INFO_REQ))
740                         msg = odata[0];
741
742         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
743         return msg;
744 }
745
746
747 // Collect all advertised servers
748 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
749                 const void *opt, const void *end)
750 {
751         uint16_t olen, otype;
752         uint8_t *odata, pref = 0;
753         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
754                                         DHCPV6_SOL_MAX_RT,
755                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
756         bool have_na = false;
757         int have_pd = 0;
758
759         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
760                 if (orig == DHCPV6_MSG_SOLICIT &&
761                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
762                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
763                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
764                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
765                 }
766
767                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
768                         memcpy(cand.duid, odata, olen);
769                         cand.duid_len = olen;
770                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
771                         int error = ((int)odata[0] << 8 | (int)odata[1]);
772
773                         switch (error) {
774                         case DHCPV6_NoPrefixAvail:
775                                 // Status code on global level
776                                 cand.preference -= 2000;
777                                 break;
778
779                         default :
780                                 break;
781                         }
782                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
783                                 cand.preference >= 0) {
784                         cand.preference = pref = odata[0];
785                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
786                         cand.wants_reconfigure = true;
787                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
788                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
789                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
790                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
791                                 cand.sol_max_rt = sol_max_rt;
792                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
793                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
794                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
795                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
796                                 cand.inf_max_rt = inf_max_rt;
797                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
798                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
799                         uint8_t *oend = odata + olen, *d;
800                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
801                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
802                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
803                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
804                                         have_pd = p->prefix;
805                                 }
806                         }
807                 } else if (otype == DHCPV6_OPT_IA_NA) {
808                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
809                         uint8_t *oend = odata + olen, *d;
810                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
811                                 if (otype == DHCPV6_OPT_IA_ADDR)
812                                         have_na = true;
813                 }
814         }
815
816         if ((!have_na && na_mode == IA_MODE_FORCE) ||
817                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
818                 /*
819                  * RFC7083 states to process the SOL_MAX_RT and
820                  * INF_MAX_RT options even if the DHCPv6 server
821                  * did not propose any IA_NA and/or IA_PD
822                  */
823                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
824                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
825                 return -1;
826         }
827
828         if (na_mode != IA_MODE_NONE && !have_na) {
829                 cand.has_noaddravail = true;
830                 cand.preference -= 1000;
831         }
832
833         if (pd_mode != IA_MODE_NONE) {
834                 if (have_pd)
835                         cand.preference += 2000 + (128 - have_pd);
836                 else
837                         cand.preference -= 2000;
838         }
839
840         if (cand.duid_len > 0) {
841                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
842                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
843                 dhcpv6_add_server_cand(&cand);
844         }
845
846         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
847 }
848
849
850 static int dhcpv6_commit_advert(void)
851 {
852         return dhcpv6_promote_server_cand();
853 }
854
855
856 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
857                 const void *opt, const void *end)
858 {
859         dhcpv6_handle_advert(orig, rc, opt, end);
860         if (dhcpv6_commit_advert() < 0)
861                 return -1;
862
863         return dhcpv6_handle_reply(orig, rc, opt, end);
864 }
865
866
867 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
868                 const void *opt, const void *end)
869 {
870         uint8_t *odata;
871         uint16_t otype, olen;
872         uint32_t refresh = UINT32_MAX;
873         int ret = 1;
874         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
875
876         odhcp6c_expire();
877
878         if (orig == DHCPV6_MSG_UNKNOWN) {
879                 static time_t last_update = 0;
880                 time_t now = odhcp6c_get_milli_time() / 1000;
881
882                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
883                 last_update = now;
884
885                 if (t1 != UINT32_MAX)
886                         t1 -= elapsed;
887
888                 if (t2 != UINT32_MAX)
889                         t2 -= elapsed;
890
891                 if (t3 != UINT32_MAX)
892                         t3 -= elapsed;
893
894                 if (t1 < 0)
895                         t1 = 0;
896
897                 if (t2 < 0)
898                         t2 = 0;
899
900                 if (t3 < 0)
901                         t3 = 0;
902         }
903
904         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
905                 // Delete NA and PD we have in the state from the Advert
906                 odhcp6c_clear_state(STATE_IA_NA);
907                 odhcp6c_clear_state(STATE_IA_PD);
908         }
909
910         if (opt) {
911                 odhcp6c_clear_state(STATE_DNS);
912                 odhcp6c_clear_state(STATE_SEARCH);
913                 odhcp6c_clear_state(STATE_SNTP_IP);
914                 odhcp6c_clear_state(STATE_NTP_IP);
915                 odhcp6c_clear_state(STATE_NTP_FQDN);
916                 odhcp6c_clear_state(STATE_SIP_IP);
917                 odhcp6c_clear_state(STATE_SIP_FQDN);
918                 odhcp6c_clear_state(STATE_AFTR_NAME);
919                 odhcp6c_clear_state(STATE_CER);
920                 odhcp6c_clear_state(STATE_S46_MAPT);
921                 odhcp6c_clear_state(STATE_S46_MAPE);
922                 odhcp6c_clear_state(STATE_S46_LW);
923                 odhcp6c_clear_state(STATE_PASSTHRU);
924         }
925
926         // Parse and find all matching IAs
927         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
928                 bool passthru = true;
929
930                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
931                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
932                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
933
934                         // Test ID
935                         if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
936                                 continue;
937
938                         uint16_t code = DHCPV6_Success;
939                         uint16_t stype, slen;
940                         uint8_t *sdata;
941                         // Get and handle status code
942                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
943                                         stype, slen, sdata) {
944                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
945                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
946                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
947
948                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
949
950                                         if (code == DHCPV6_Success)
951                                                 continue;
952
953                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
954                                                 code, mdata, mlen, handled_status_codes, &ret);
955
956
957                                         if (ret > 0)
958                                                 return ret;
959                                         break;
960                                 }
961                         }
962
963                         if (code != DHCPV6_Success)
964                                 continue;
965
966                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
967                         passthru = false;
968                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
969                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
970                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
971                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
972
973                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
974                         passthru = false;
975                 }
976                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
977                         if (olen % 16 == 0)
978                                 odhcp6c_add_state(STATE_DNS, odata, olen);
979                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
980                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
981                         passthru = false;
982                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
983                         if (olen % 16 == 0)
984                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
985                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
986                         uint16_t stype, slen;
987                         uint8_t *sdata;
988                         // Test status and bail if error
989                         dhcpv6_for_each_option(odata, odata + olen,
990                                         stype, slen, sdata) {
991                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
992                                                 stype == NTP_SRV_ADDR))
993                                         odhcp6c_add_state(STATE_NTP_IP,
994                                                         sdata, slen);
995                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
996                                         odhcp6c_add_state(STATE_NTP_FQDN,
997                                                         sdata, slen);
998                         }
999                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1000                         if (olen == 16)
1001                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1002                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1003                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1004                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1005                         refresh = ntohl(*((uint32_t*)odata));
1006                         passthru = false;
1007                 } else if (otype == DHCPV6_OPT_AUTH) {
1008                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1009                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1010                                 if (r->protocol == 3 && r->algorithm == 1 &&
1011                                                 r->reconf_type == 1)
1012                                         memcpy(reconf_key, r->key, sizeof(r->key));
1013                         }
1014                         passthru = false;
1015                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1016                         size_t cur_len;
1017                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1018                         if (cur_len == 0)
1019                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1020                         passthru = false;
1021                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1022                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1023                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1024                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1025                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1026                         passthru = false;
1027                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1028                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1029                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1030                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1031                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1032                         passthru = false;
1033 #ifdef EXT_CER_ID
1034                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1035                                 sizeof(struct dhcpv6_cer_id)) {
1036                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1037                         struct in6_addr any = IN6ADDR_ANY_INIT;
1038                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1039                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1040                         passthru = false;
1041 #endif
1042                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1043                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1044                         passthru = false;
1045                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1046                         size_t mape_len;
1047                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1048                         if (mape_len == 0)
1049                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1050                         passthru = false;
1051                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1052                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1053                         passthru = false;
1054                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1055                                 otype == DHCPV6_OPT_SERVERID ||
1056                                 otype == DHCPV6_OPT_IA_TA ||
1057                                 otype == DHCPV6_OPT_PREF ||
1058                                 otype == DHCPV6_OPT_UNICAST ||
1059                                 otype == DHCPV6_OPT_FQDN ||
1060                                 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1061                         passthru = false;
1062                 } else {
1063                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1064                 }
1065
1066                 if (passthru)
1067                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1068         }
1069
1070         if (orig != DHCPV6_MSG_INFO_REQ) {
1071                 // Update refresh timers if no fatal status code was received
1072                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1073                         switch (orig) {
1074                         case DHCPV6_MSG_RENEW:
1075                                 // Send further renews if T1 is not set
1076                                 if (!t1)
1077                                         ret = -1;
1078                                 break;
1079                         case DHCPV6_MSG_REBIND:
1080                                 // Send further rebinds if T1 and T2 is not set
1081                                 if (!t1 && !t2)
1082                                         ret = -1;
1083                                 break;
1084
1085                         case DHCPV6_MSG_REQUEST:
1086                                 // All server candidates can be cleared if not yet bound
1087                                 if (!odhcp6c_is_bound())
1088                                         dhcpv6_clear_all_server_cand();
1089
1090                         default :
1091                                 break;
1092                         }
1093                 }
1094         }
1095         else if (ret > 0) {
1096                 // All server candidates can be cleared if not yet bound
1097                 if (!odhcp6c_is_bound())
1098                         dhcpv6_clear_all_server_cand();
1099
1100                 t1 = refresh;
1101         }
1102
1103         return ret;
1104 }
1105
1106
1107 static int dhcpv6_parse_ia(void *opt, void *end)
1108 {
1109         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1110         int parsed_ia = 0;
1111         uint32_t t1, t2;
1112         uint16_t otype, olen;
1113         uint8_t *odata;
1114
1115         t1 = ntohl(ia_hdr->t1);
1116         t2 = ntohl(ia_hdr->t2);
1117
1118         if (t1 > t2)
1119                 return 0;
1120
1121         // Update address IA
1122         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1123                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1124                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1125
1126                 entry.iaid = ia_hdr->iaid;
1127
1128                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1129                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1130                         if (olen + 4U < sizeof(*prefix))
1131                                 continue;
1132
1133                         entry.valid = ntohl(prefix->valid);
1134                         entry.preferred = ntohl(prefix->preferred);
1135
1136                         if (entry.preferred > entry.valid)
1137                                 continue;
1138
1139                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1140                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1141                         if (entry.t1 > entry.t2)
1142                                 entry.t1 = entry.t2;
1143
1144                         entry.length = prefix->prefix;
1145                         entry.target = prefix->addr;
1146                         uint16_t stype, slen;
1147                         uint8_t *sdata;
1148
1149 #ifdef EXT_PREFIX_CLASS
1150                         // Find prefix class, if any
1151                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1152                                         stype, slen, sdata)
1153                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1154                                         entry.class = sdata[0] << 8 | sdata[1];
1155 #endif
1156
1157                         // Parse PD-exclude
1158                         bool ok = true;
1159                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1160                                         odata + olen, stype, slen, sdata) {
1161                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1162                                         continue;
1163
1164                                 uint8_t elen = sdata[0];
1165                                 if (elen > 64)
1166                                         elen = 64;
1167
1168                                 if (elen <= 32 || elen <= entry.length) {
1169                                         ok = false;
1170                                         continue;
1171                                 }
1172
1173
1174                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1175                                 if (slen <= bytes) {
1176                                         ok = false;
1177                                         continue;
1178                                 }
1179
1180                                 uint32_t exclude = 0;
1181                                 do {
1182                                         exclude = exclude << 8 | sdata[bytes];
1183                                 } while (--bytes);
1184
1185                                 exclude >>= 8 - ((elen - entry.length) % 8);
1186                                 exclude <<= 64 - elen;
1187
1188                                 // Abusing router & priority fields for exclusion
1189                                 entry.router = entry.target;
1190                                 entry.router.s6_addr32[1] |= htonl(exclude);
1191                                 entry.priority = elen;
1192                         }
1193
1194                         if (ok) {
1195                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1196                                 parsed_ia++;
1197                         }
1198
1199                         entry.priority = 0;
1200                         memset(&entry.router, 0, sizeof(entry.router));
1201                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1202                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1203                         if (olen + 4U < sizeof(*addr))
1204                                 continue;
1205
1206                         entry.preferred = ntohl(addr->preferred);
1207                         entry.valid = ntohl(addr->valid);
1208
1209                         if (entry.preferred > entry.valid)
1210                                 continue;
1211
1212                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1213                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1214                         if (entry.t1 > entry.t2)
1215                                 entry.t1 = entry.t2;
1216
1217                         entry.length = 128;
1218                         entry.target = addr->addr;
1219
1220 #ifdef EXT_PREFIX_CLASS
1221                         uint16_t stype, slen;
1222                         uint8_t *sdata;
1223                         // Find prefix class, if any
1224                         dhcpv6_for_each_option(&addr[1], odata + olen,
1225                                         stype, slen, sdata)
1226                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1227                                         entry.class = sdata[0] << 8 | sdata[1];
1228 #endif
1229
1230                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1231                         parsed_ia++;
1232                 }
1233         }
1234         return parsed_ia;
1235 }
1236
1237
1238 static int dhcpv6_calc_refresh_timers(void)
1239 {
1240         struct odhcp6c_entry *e;
1241         size_t ia_na_entries, ia_pd_entries, i;
1242         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1243
1244         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1245         ia_na_entries /= sizeof(*e);
1246         for (i = 0; i < ia_na_entries; i++) {
1247                 if (e[i].t1 < l_t1)
1248                         l_t1 = e[i].t1;
1249
1250                 if (e[i].t2 < l_t2)
1251                         l_t2 = e[i].t2;
1252
1253                 if (e[i].valid > l_t3)
1254                         l_t3 = e[i].valid;
1255         }
1256
1257         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1258         ia_pd_entries /= sizeof(*e);
1259         for (i = 0; i < ia_pd_entries; i++) {
1260                 if (e[i].t1 < l_t1)
1261                         l_t1 = e[i].t1;
1262
1263                 if (e[i].t2 < l_t2)
1264                         l_t2 = e[i].t2;
1265
1266                 if (e[i].valid > l_t3)
1267                         l_t3 = e[i].valid;
1268         }
1269
1270         if (ia_pd_entries || ia_na_entries) {
1271                 t1 = l_t1;
1272                 t2 = l_t2;
1273                 t3 = l_t3;
1274         } else {
1275                 t1 = 600;
1276         }
1277
1278         return (int)(ia_pd_entries + ia_na_entries);
1279 }
1280
1281
1282 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1283                 const void *status_msg, const int len)
1284 {
1285         uint8_t buf[len + 3];
1286
1287         memset(buf, 0, sizeof(buf));
1288         if (len) {
1289                 buf[0] = '(';
1290                 memcpy(&buf[1], status_msg, len);
1291                 buf[len + 1] = ')';
1292         }
1293
1294         syslog(LOG_WARNING, "Server returned %s status %i %s",
1295                 scope, code, buf);
1296 }
1297
1298
1299 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1300                 const uint16_t code, const void *status_msg, const int len,
1301                 int *ret)
1302 {
1303         dhcpv6_log_status_code(code, "message", status_msg, len);
1304
1305         switch (code) {
1306         case DHCPV6_UnspecFail:
1307                 // Generic failure
1308                 *ret = 0;
1309                 break;
1310
1311         case DHCPV6_UseMulticast:
1312                 // TODO handle multicast status code
1313                 break;
1314
1315         case DHCPV6_NoAddrsAvail:
1316         case DHCPV6_NoPrefixAvail:
1317                 if (orig == DHCPV6_MSG_REQUEST)
1318                         *ret = 0; // Failure
1319                 break;
1320
1321         default:
1322                 break;
1323         }
1324 }
1325
1326
1327 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1328                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1329                 const void *status_msg, const int len,
1330                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1331 {
1332         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1333                 "IA_NA" : "IA_PD", status_msg, len);
1334
1335         switch (code) {
1336         case DHCPV6_NoBinding:
1337                 switch (orig) {
1338                 case DHCPV6_MSG_RENEW:
1339                 case DHCPV6_MSG_REBIND:
1340                         if ((*ret > 0) && !handled_status_codes[code])
1341                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1342                         break;
1343
1344                 default:
1345                         break;
1346                 }
1347                 break;
1348
1349         case DHCPV6_NoAddrsAvail:
1350         case DHCPV6_NoPrefixAvail:
1351                 switch (orig) {
1352                 case DHCPV6_MSG_REQUEST:
1353                         if (*ret != 0)
1354                                 *ret = 0;
1355                         break;
1356                 default:
1357                         break;
1358                 }
1359                 break;
1360
1361         case DHCPV6_NotOnLink:
1362                 // TODO handle not onlink in case of confirm
1363                 break;
1364
1365         default:
1366                 break;
1367         }
1368 }
1369
1370 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1371 {
1372         size_t cand_len, i;
1373         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1374
1375         // Remove identical duid server candidate
1376         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1377                 if (cand->duid_len == c[i].duid_len &&
1378                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1379                         free(c[i].ia_na);
1380                         free(c[i].ia_pd);
1381                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1382                         break;
1383                 }
1384         }
1385
1386         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1387                 i < cand_len / sizeof(*c); ++i) {
1388                 if (c[i].preference < cand->preference)
1389                         break;
1390         }
1391
1392         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1393 }
1394
1395 static void dhcpv6_clear_all_server_cand(void)
1396 {
1397         size_t cand_len, i;
1398         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1399
1400         // Server candidates need deep delete for IA_NA/IA_PD
1401         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1402                 free(c[i].ia_na);
1403                 free(c[i].ia_pd);
1404         }
1405         odhcp6c_clear_state(STATE_SERVER_CAND);
1406 }
1407
1408 int dhcpv6_promote_server_cand(void)
1409 {
1410         size_t cand_len;
1411         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1412         uint16_t hdr[2];
1413         int ret = DHCPV6_STATELESS;
1414
1415         // Clear lingering candidate state info
1416         odhcp6c_clear_state(STATE_SERVER_ID);
1417         odhcp6c_clear_state(STATE_IA_NA);
1418         odhcp6c_clear_state(STATE_IA_PD);
1419
1420         if (!cand_len)
1421                 return -1;
1422
1423         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1424                 na_mode = IA_MODE_NONE;
1425
1426                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1427                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1428
1429                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1430         }
1431
1432         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1433         hdr[1] = htons(cand->duid_len);
1434         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1435         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1436         accept_reconfig = cand->wants_reconfigure;
1437         if (cand->ia_na_len) {
1438                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1439                 free(cand->ia_na);
1440                 if (na_mode != IA_MODE_NONE)
1441                         ret = DHCPV6_STATEFUL;
1442         }
1443         if (cand->ia_pd_len) {
1444                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1445                 free(cand->ia_pd);
1446                 if (request_prefix)
1447                         ret = DHCPV6_STATEFUL;
1448         }
1449
1450         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1451         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1452
1453         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1454
1455         return ret;
1456 }