GNUnet  0.10.x
gnunet-service-resolver.c
Go to the documentation of this file.
1 /*
2  This file is part of GNUnet.
3  Copyright (C) 2007-2016 GNUnet e.V.
4 
5  GNUnet is free software: you can redistribute it and/or modify it
6  under the terms of the GNU Affero General Public License as published
7  by the Free Software Foundation, either version 3 of the License,
8  or (at your option) any later version.
9 
10  GNUnet is distributed in the hope that it will be useful, but
11  WITHOUT ANY WARRANTY; without even the implied warranty of
12  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  Affero General Public License for more details.
14 
15  You should have received a copy of the GNU Affero General Public License
16  along with this program. If not, see <http://www.gnu.org/licenses/>.
17 
18  SPDX-License-Identifier: AGPL3.0-or-later
19 */
20 
26 #include "platform.h"
27 #include "gnunet_util_lib.h"
28 #include "gnunet_protocols.h"
30 #include "resolver.h"
31 
32 
36 #define DNS_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
37 
41 #define MAX_CACHE 1024
42 
47 {
52 
57 
62 };
63 
64 
69 {
73  struct ResolveCache *next;
74 
78  struct ResolveCache *prev;
79 
83  char *hostname;
84 
89 
94 };
95 
96 
101 {
106 
111 
116 
121 
126 
130  char *hostname;
131 
136  int did_aaaa;
137 
141  uint16_t record_type;
142 
148 
153  uint16_t dns_id;
154 };
155 
156 
160 static struct ResolveCache *cache_head;
161 
165 static struct ResolveCache *cache_tail;
166 
170 static struct ResolveCache *hosts_head;
171 
175 static struct ResolveCache *hosts_tail;
176 
180 static struct ActiveLookup *lookup_head;
181 
185 static struct ActiveLookup *lookup_tail;
186 
191 
195 static char *my_domain;
196 
200 static unsigned int cache_size;
201 
202 
208 static void
210 {
211  struct RecordListEntry *pos;
212 
213  while (NULL != (pos = rc->records_head))
214  {
217  GNUNET_free (pos->record);
218  GNUNET_free (pos);
219  }
221  GNUNET_CONTAINER_DLL_remove (cache_head, cache_tail, rc);
222  cache_size--;
223  GNUNET_free (rc);
224 }
225 
226 
232 static void
234 {
235  struct RecordListEntry *pos;
236 
237  while (NULL != (pos = rc->records_head))
238  {
241  GNUNET_free (pos->record);
242  GNUNET_free (pos);
243  }
245  GNUNET_CONTAINER_DLL_remove (hosts_head, hosts_tail, rc);
246  cache_size--;
247  GNUNET_free (rc);
248 }
249 
250 
256 static void
258 {
259  GNUNET_CONTAINER_DLL_remove (lookup_head, lookup_tail, al);
260  if (NULL != al->resolve_handle)
261  {
263  al->resolve_handle = NULL;
264  }
265  if (NULL != al->timeout_task)
266  {
268  al->timeout_task = NULL;
269  }
271  GNUNET_free (al);
272 }
273 
274 
284 static char *
285 extract_dns_server (const char *line, size_t line_len)
286 {
287  if (0 == strncmp (line, "nameserver ", strlen ("nameserver ")))
288  return GNUNET_strndup (line + strlen ("nameserver "),
289  line_len - strlen ("nameserver "));
290  return NULL;
291 }
292 
293 
303 static char *
304 extract_search_domain (const char *line, size_t line_len)
305 {
306  if (0 == strncmp (line, "search ", strlen ("search ")))
307  return GNUNET_strndup (line + strlen ("search "),
308  line_len - strlen ("search "));
309  return NULL;
310 }
311 
312 
319 static int
320 lookup_dns_servers (char ***server_addrs)
321 {
322  struct GNUNET_DISK_FileHandle *fh;
323  struct GNUNET_DISK_MapHandle *mh;
324  off_t bytes_read;
325  const char *buf;
326  size_t read_offset;
327  unsigned int num_dns_servers;
328 
329  fh = GNUNET_DISK_file_open ("/etc/resolv.conf",
332  if (NULL == fh)
333  {
335  "Could not open /etc/resolv.conf. "
336  "DNS resolution will not be possible.\n");
337  return -1;
338  }
339  if (GNUNET_OK != GNUNET_DISK_file_handle_size (fh, &bytes_read))
340  {
342  "Could not determine size of /etc/resolv.conf. "
343  "DNS resolution will not be possible.\n");
345  return -1;
346  }
347  if (((unsigned long long) bytes_read) > (unsigned long long) SIZE_MAX)
348  {
350  "/etc/resolv.conf file too large to mmap. "
351  "DNS resolution will not be possible.\n");
353  return -1;
354  }
355  buf = GNUNET_DISK_file_map (fh,
356  &mh,
358  (size_t) bytes_read);
359  *server_addrs = NULL;
360  read_offset = 0;
361  num_dns_servers = 0;
362  while (read_offset < (size_t) bytes_read)
363  {
364  const char *newline;
365  size_t line_len;
366  char *dns_server;
367 
368  newline = strchr (buf + read_offset, '\n');
369  if (NULL == newline)
370  break;
371  line_len = newline - buf - read_offset;
372  dns_server = extract_dns_server (buf + read_offset, line_len);
373  if (NULL != dns_server)
374  {
375  GNUNET_array_append (*server_addrs, num_dns_servers, dns_server);
376  }
377  else if (NULL == my_domain)
378  {
379  my_domain = extract_search_domain (buf + read_offset, line_len);
380  }
381  read_offset += line_len + 1;
382  }
385  return (int) num_dns_servers;
386 }
387 
388 
395 static char *
396 make_reverse_hostname (const void *ip, int af)
397 {
398  char *buf = GNUNET_new_array (80, char);
399  int pos = 0;
400 
401  if (AF_INET == af)
402  {
403  struct in_addr *addr = (struct in_addr *) ip;
404  uint32_t ip_int = addr->s_addr;
405 
406  for (int i = 3; i >= 0; i--)
407  {
408  int n =
409  GNUNET_snprintf (buf + pos, 80 - pos, "%u.", ((uint8_t *) &ip_int)[i]);
410  if (n < 0)
411  {
412  GNUNET_free (buf);
413  return NULL;
414  }
415  pos += n;
416  }
417  pos += GNUNET_snprintf (buf + pos, 80 - pos, "in-addr.arpa");
418  }
419  else if (AF_INET6 == af)
420  {
421  struct in6_addr *addr = (struct in6_addr *) ip;
422  for (int i = 15; i >= 0; i--)
423  {
424  int n =
425  GNUNET_snprintf (buf + pos, 80 - pos, "%x.", addr->s6_addr[i] & 0xf);
426  if (n < 0)
427  {
428  GNUNET_free (buf);
429  return NULL;
430  }
431  pos += n;
432  n = GNUNET_snprintf (buf + pos, 80 - pos, "%x.", addr->s6_addr[i] >> 4);
433  if (n < 0)
434  {
435  GNUNET_free (buf);
436  return NULL;
437  }
438  pos += n;
439  }
440  pos += GNUNET_snprintf (buf + pos, 80 - pos, "ip6.arpa");
441  }
442  buf[pos] = '\0';
443  return buf;
444 }
445 
446 
458 static int
460  uint16_t record_type,
461  uint32_t client_request_id,
462  struct GNUNET_SERVICE_Client *client)
463 {
465  struct GNUNET_MQ_Envelope *env;
466  const void *payload;
467  size_t payload_len;
468 
469  switch (record->type)
470  {
472  if (GNUNET_DNSPARSER_TYPE_CNAME != record_type)
473  return GNUNET_NO;
474  payload = record->data.hostname;
475  payload_len = strlen (record->data.hostname) + 1;
476  break;
478  if (GNUNET_DNSPARSER_TYPE_PTR != record_type)
479  return GNUNET_NO;
480  payload = record->data.hostname;
481  payload_len = strlen (record->data.hostname) + 1;
482  break;
484  if ((GNUNET_DNSPARSER_TYPE_A != record_type) &&
485  (GNUNET_DNSPARSER_TYPE_ALL != record_type))
486  return GNUNET_NO;
487  payload = record->data.raw.data;
488  payload_len = record->data.raw.data_len;
489  break;
491  if ((GNUNET_DNSPARSER_TYPE_AAAA != record_type) &&
492  (GNUNET_DNSPARSER_TYPE_ALL != record_type))
493  return GNUNET_NO;
494  payload = record->data.raw.data;
495  payload_len = record->data.raw.data_len;
496  break;
497  default:
499  "Cannot handle DNS response type %u: not supported here\n",
500  record->type);
501  return GNUNET_NO;
502  }
503  env = GNUNET_MQ_msg_extra (msg,
504  payload_len,
506  msg->client_id = client_request_id;
507  GNUNET_memcpy (&msg[1], payload, payload_len);
509  return GNUNET_YES;
510 }
511 
512 
520 static void
521 send_end_msg (uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
522 {
524  struct GNUNET_MQ_Envelope *env;
525 
526  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending END message\n");
528  msg->client_id = client_request_id;
530 }
531 
532 
540 static int
542 {
544  struct RecordListEntry *n;
545 
546  for (struct RecordListEntry *pos = rc->records_head; NULL != pos; pos = n)
547  {
548  n = pos->next;
549  if (now.abs_value_us > pos->record->expiration_time.abs_value_us)
550  {
552  GNUNET_DNSPARSER_free_record (pos->record);
553  GNUNET_free (pos->record);
554  GNUNET_free (pos);
555  }
556  }
557  if (NULL == rc->records_head)
558  {
559  free_cache_entry (rc);
560  return GNUNET_YES;
561  }
562  return GNUNET_NO;
563 }
564 
565 
575 static void
576 process_get (const char *hostname,
577  uint16_t record_type,
578  uint32_t client_request_id,
579  struct GNUNET_SERVICE_Client *client);
580 
581 
593 static int
594 try_cache (const char *hostname,
595  uint16_t record_type,
596  uint32_t client_request_id,
597  struct GNUNET_SERVICE_Client *client)
598 {
599  struct ResolveCache *pos;
600  struct ResolveCache *next;
601  int found;
602  int in_hosts;
603 
604  in_hosts = GNUNET_NO;
605  for (pos = hosts_head; NULL != pos; pos = pos->next)
606  if (0 == strcmp (pos->hostname, hostname))
607  {
608  in_hosts = GNUNET_YES;
609  break;
610  }
611  if (NULL == pos)
612  {
613  next = cache_head;
614  for (pos = next; NULL != pos; pos = next)
615  {
616  next = pos->next;
617  if (GNUNET_YES == remove_expired (pos))
618  continue;
619  if (0 == strcmp (pos->hostname, hostname))
620  break;
621  }
622  }
623  if (NULL == pos)
624  {
625  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No cache entry for '%s'\n", hostname);
626  return GNUNET_NO;
627  }
628  if ((GNUNET_NO == in_hosts) && (cache_head != pos))
629  {
630  /* move result to head to achieve LRU for cache eviction */
631  GNUNET_CONTAINER_DLL_remove (cache_head, cache_tail, pos);
632  GNUNET_CONTAINER_DLL_insert (cache_head, cache_tail, pos);
633  }
634  found = GNUNET_NO;
635  for (struct RecordListEntry *rle = pos->records_head; NULL != rle;
636  rle = rle->next)
637  {
638  const struct GNUNET_DNSPARSER_Record *record = rle->record;
639 
641  "Found cache entry for '%s', record type '%u'\n",
642  hostname,
643  record_type);
644  if ((GNUNET_DNSPARSER_TYPE_CNAME == record->type) &&
645  (GNUNET_DNSPARSER_TYPE_CNAME != record_type) && (GNUNET_NO == found))
646  {
647  const char *hostname = record->data.hostname;
648 
649  process_get (hostname, record_type, client_request_id, client);
650  return GNUNET_YES; /* counts as a cache "hit" */
651  }
652  found |= send_reply (rle->record, record_type, client_request_id, client);
653  }
654  if (GNUNET_NO == found)
655  return GNUNET_NO; /* had records, but none matched! */
656  send_end_msg (client_request_id, client);
657  return GNUNET_YES;
658 }
659 
660 
672 static int
673 pack (const char *hostname,
674  uint16_t type,
675  uint16_t dns_id,
676  char **packet_buf,
677  size_t *packet_size)
678 {
679  struct GNUNET_DNSPARSER_Query query;
680  struct GNUNET_DNSPARSER_Packet packet;
681 
682  query.name = (char *) hostname;
683  query.type = type;
685  memset (&packet, 0, sizeof (packet));
686  packet.num_queries = 1;
687  packet.queries = &query;
688  packet.id = htons (dns_id);
689  packet.flags.recursion_desired = 1;
690  if (GNUNET_OK !=
691  GNUNET_DNSPARSER_pack (&packet, UINT16_MAX, packet_buf, packet_size))
692  {
694  "Failed to pack query for hostname `%s'\n",
695  hostname);
696  packet_buf = NULL;
697  return GNUNET_SYSERR;
698  }
699  return GNUNET_OK;
700 }
701 
702 static void
703 cache_answers (const char *name,
705  unsigned int num_records)
706 {
707  struct ResolveCache *rc;
709  struct RecordListEntry *rle;
710 
711  for (unsigned int i = 0; i != num_records; i++)
712  {
713  record = &records[i];
714 
715  for (rc = cache_head; NULL != rc; rc = rc->next)
716  if (0 == strcasecmp (rc->hostname, name))
717  break;
718  if (NULL == rc)
719  {
720  rc = GNUNET_new (struct ResolveCache);
721  rc->hostname = GNUNET_strdup (name);
722  GNUNET_CONTAINER_DLL_insert (cache_head, cache_tail, rc);
723  cache_size++;
724  }
725  /* TODO: ought to check first if we have this exact record
726  already in the cache! */
727  rle = GNUNET_new (struct RecordListEntry);
730  }
731 }
732 
741 static void
743  const struct GNUNET_TUN_DnsHeader *dns,
744  size_t dns_len)
745 {
746  struct ActiveLookup *al = cls;
747  struct GNUNET_DNSPARSER_Packet *parsed;
748 
749  parsed = GNUNET_DNSPARSER_parse ((const char *) dns, dns_len);
750  if (NULL == parsed)
751  {
753  "Failed to parse DNS reply (hostname %s, request ID %u)\n",
754  al->hostname,
755  al->dns_id);
756  return;
757  }
758  if (al->dns_id != ntohs (parsed->id))
759  {
761  "Request ID in DNS reply does not match\n");
763  return;
764  }
765  if (0 == parsed->num_answers + parsed->num_authority_records +
766  parsed->num_additional_records)
767  {
769  "DNS reply (hostname %s, request ID %u) contains no answers\n",
770  al->hostname,
771  (unsigned int) al->client_request_id);
772  /* resume by trying again from cache */
773  if (GNUNET_NO == try_cache (al->hostname,
774  al->record_type,
775  al->client_request_id,
776  al->client))
777  /* cache failed, tell client we could not get an answer */
778  {
780  }
782  free_active_lookup (al);
783  return;
784  }
785  /* LRU-based cache eviction: we remove from tail */
786  while (cache_size > MAX_CACHE)
787  free_cache_entry (cache_tail);
788 
790  "Got reply for hostname %s and request ID %u\n",
791  al->hostname,
792  (unsigned int) al->client_request_id);
793  /* add to cache */
794  cache_answers (al->hostname, parsed->answers, parsed->num_answers);
795  cache_answers (al->hostname,
796  parsed->authority_records,
797  parsed->num_authority_records);
798  cache_answers (al->hostname,
799  parsed->additional_records,
800  parsed->num_additional_records);
801 
802  /* see if we need to do the 2nd request for AAAA records */
803  if ((GNUNET_DNSPARSER_TYPE_ALL == al->record_type) &&
804  (GNUNET_NO == al->did_aaaa))
805  {
806  char *packet_buf;
807  size_t packet_size;
808  uint16_t dns_id;
809 
811  UINT16_MAX);
812  if (GNUNET_OK == pack (al->hostname,
814  dns_id,
815  &packet_buf,
816  &packet_size))
817  {
818  al->did_aaaa = GNUNET_YES;
819  al->dns_id = dns_id;
821  al->resolve_handle = GNUNET_DNSSTUB_resolve (dnsstub_ctx,
822  packet_buf,
823  packet_size,
825  al);
826  GNUNET_free (packet_buf);
828  return;
829  }
830  }
831 
832  /* resume by trying again from cache */
833  if (GNUNET_NO == try_cache (al->hostname,
834  al->record_type,
835  al->client_request_id,
836  al->client))
837  /* cache failed, tell client we could not get an answer */
838  {
840  }
841  free_active_lookup (al);
843 }
844 
845 
852 static void
854 {
855  struct ActiveLookup *al = cls;
856 
857  al->timeout_task = NULL;
858  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "DNS lookup timeout!\n");
860  free_active_lookup (al);
861 }
862 
863 
874 static int
876  uint16_t record_type,
877  uint32_t client_request_id,
878  struct GNUNET_SERVICE_Client *client)
879 {
880  char *packet_buf;
881  size_t packet_size;
882  struct ActiveLookup *al;
883  uint16_t dns_id;
884  uint16_t type;
885 
886  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "resolve_and_cache `%s'\n", hostname);
888  UINT16_MAX);
889 
890  if (GNUNET_DNSPARSER_TYPE_ALL == record_type)
892  else
893  type = record_type;
894  if (GNUNET_OK != pack (hostname, type, dns_id, &packet_buf, &packet_size))
895  {
897  "Failed to pack query for hostname `%s'\n",
898  hostname);
899  return GNUNET_SYSERR;
900  }
901 
902  al = GNUNET_new (struct ActiveLookup);
903  al->hostname = GNUNET_strdup (hostname);
904  al->record_type = record_type;
906  al->dns_id = dns_id;
907  al->client = client;
908  al->timeout_task =
910  al->resolve_handle = GNUNET_DNSSTUB_resolve (dnsstub_ctx,
911  packet_buf,
912  packet_size,
914  al);
915  GNUNET_free (packet_buf);
916  GNUNET_CONTAINER_DLL_insert (lookup_head, lookup_tail, al);
918  "Resolving %s, client_request_id = %u, dns_id = %u\n",
919  hostname,
920  (unsigned int) client_request_id,
921  (unsigned int) dns_id);
922  return GNUNET_OK;
923 }
924 
925 
935 static void
936 process_get (const char *hostname,
937  uint16_t record_type,
938  uint32_t client_request_id,
939  struct GNUNET_SERVICE_Client *client)
940 {
941  char fqdn[255];
942 
943  if (GNUNET_NO != try_cache (hostname, record_type, client_request_id, client))
944  return;
945  if ((NULL != my_domain) && (NULL == strchr (hostname, (unsigned char) '.')) &&
946  (strlen (hostname) + strlen (my_domain) <= 253))
947  {
948  GNUNET_snprintf (fqdn, sizeof (fqdn), "%s.%s", hostname, my_domain);
949  }
950  else if (strlen (hostname) < 255)
951  {
952  GNUNET_snprintf (fqdn, sizeof (fqdn), "%s", hostname);
953  }
954  else
955  {
956  GNUNET_break (0);
958  return;
959  }
960  if (GNUNET_NO == try_cache (fqdn, record_type, client_request_id, client))
961  {
962  if (GNUNET_OK !=
963  resolve_and_cache (fqdn, record_type, client_request_id, client))
964  {
965  send_end_msg (client_request_id, client);
966  }
967  }
968 }
969 
970 
978 static int
979 check_get (void *cls, const struct GNUNET_RESOLVER_GetMessage *get)
980 {
981  uint16_t size;
982  int direction;
983  int af;
984 
985  (void) cls;
986  size = ntohs (get->header.size) - sizeof (*get);
987  direction = ntohl (get->direction);
988  if (GNUNET_NO == direction)
989  {
991  return GNUNET_OK;
992  }
993  af = ntohl (get->af);
994  switch (af)
995  {
996  case AF_INET:
997  if (size != sizeof (struct in_addr))
998  {
999  GNUNET_break (0);
1000  return GNUNET_SYSERR;
1001  }
1002  break;
1003  case AF_INET6:
1004  if (size != sizeof (struct in6_addr))
1005  {
1006  GNUNET_break (0);
1007  return GNUNET_SYSERR;
1008  }
1009  break;
1010  default:
1011  GNUNET_break (0);
1012  return GNUNET_SYSERR;
1013  }
1014  return GNUNET_OK;
1015 }
1016 
1017 
1024 static void
1025 handle_get (void *cls, const struct GNUNET_RESOLVER_GetMessage *msg)
1026 {
1027  struct GNUNET_SERVICE_Client *client = cls;
1028  int direction;
1029  int af;
1030  uint32_t client_request_id;
1031  char *hostname;
1032 
1033  direction = ntohl (msg->direction);
1034  af = ntohl (msg->af);
1035  client_request_id = msg->client_id;
1037  if (GNUNET_NO == direction)
1038  {
1039  /* IP from hostname */
1040  hostname = GNUNET_strdup ((const char *) &msg[1]);
1042  "Client asks to resolve `%s'\n",
1043  hostname);
1044  switch (af)
1045  {
1046  case AF_UNSPEC: {
1047  process_get (hostname,
1049  client_request_id,
1050  client);
1051  break;
1052  }
1053  case AF_INET: {
1054  process_get (hostname,
1056  client_request_id,
1057  client);
1058  break;
1059  }
1060  case AF_INET6: {
1061  process_get (hostname,
1063  client_request_id,
1064  client);
1065  break;
1066  }
1067  default: {
1068  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "got invalid af: %d\n", af);
1069  GNUNET_assert (0);
1070  }
1071  }
1072  }
1073  else
1074  {
1075  /* hostname from IP */
1076  hostname = make_reverse_hostname (&msg[1], af);
1077  process_get (hostname,
1079  client_request_id,
1080  client);
1081  }
1082  GNUNET_free_non_null (hostname);
1083 }
1084 
1085 
1091 static void
1092 shutdown_task (void *cls)
1093 {
1094  (void) cls;
1095 
1096  while (NULL != lookup_head)
1097  free_active_lookup (lookup_head);
1098  while (NULL != cache_head)
1099  free_cache_entry (cache_head);
1100  while (NULL != hosts_head)
1101  free_hosts_entry (hosts_head);
1102  GNUNET_DNSSTUB_stop (dnsstub_ctx);
1104 }
1105 
1106 
1116 static void
1117 add_host (const char *hostname,
1118  uint16_t rec_type,
1119  const void *data,
1120  size_t data_size)
1121 {
1122  struct ResolveCache *rc;
1123  struct RecordListEntry *rle;
1124  struct GNUNET_DNSPARSER_Record *rec;
1125 
1126  rec = GNUNET_malloc (sizeof (struct GNUNET_DNSPARSER_Record));
1128  rec->type = rec_type;
1130  rec->name = GNUNET_strdup (hostname);
1131  rec->data.raw.data = GNUNET_memdup (data, data_size);
1132  rec->data.raw.data_len = data_size;
1133  rle = GNUNET_new (struct RecordListEntry);
1134  rle->record = rec;
1135  rc = GNUNET_new (struct ResolveCache);
1136  rc->hostname = GNUNET_strdup (hostname);
1138  GNUNET_CONTAINER_DLL_insert (hosts_head, hosts_tail, rc);
1139 }
1140 
1141 
1148 static void
1149 extract_hosts (const char *line, size_t line_len)
1150 {
1151  const char *c;
1152  struct in_addr v4;
1153  struct in6_addr v6;
1154  char *tbuf;
1155  char *tok;
1156 
1157  /* ignore everything after '#' */
1158  c = memrchr (line, (unsigned char) '#', line_len);
1159  if (NULL != c)
1160  line_len = c - line;
1161  /* ignore leading whitespace */
1162  while ((0 < line_len) && isspace ((unsigned char) *line))
1163  {
1164  line++;
1165  line_len--;
1166  }
1167  tbuf = GNUNET_strndup (line, line_len);
1168  tok = strtok (tbuf, " \t");
1169  if (NULL == tok)
1170  {
1171  GNUNET_free (tbuf);
1172  return;
1173  }
1174  if (1 == inet_pton (AF_INET, tok, &v4))
1175  {
1176  while (NULL != (tok = strtok (NULL, " \t")))
1177  add_host (tok, GNUNET_DNSPARSER_TYPE_A, &v4, sizeof (struct in_addr));
1178  }
1179  else if (1 == inet_pton (AF_INET6, tok, &v6))
1180  {
1181  while (NULL != (tok = strtok (NULL, " \t")))
1182  add_host (tok, GNUNET_DNSPARSER_TYPE_AAAA, &v6, sizeof (struct in6_addr));
1183  }
1184  GNUNET_free (tbuf);
1185 }
1186 
1187 
1191 static void
1193 {
1194  struct GNUNET_DISK_FileHandle *fh;
1195  struct GNUNET_DISK_MapHandle *mh;
1196  off_t bytes_read;
1197  const char *buf;
1198  size_t read_offset;
1199 
1200  fh = GNUNET_DISK_file_open ("/etc/hosts",
1203  if (NULL == fh)
1204  {
1205  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Failed to open /etc/hosts");
1206  return;
1207  }
1208  if (GNUNET_OK != GNUNET_DISK_file_handle_size (fh, &bytes_read))
1209  {
1211  "Could not determin size of /etc/hosts. "
1212  "DNS resolution will not be possible.\n");
1214  return;
1215  }
1216  if (((unsigned long long) bytes_read) > (unsigned long long) SIZE_MAX)
1217  {
1219  "/etc/hosts file too large to mmap. "
1220  "DNS resolution will not be possible.\n");
1222  return;
1223  }
1224  buf = GNUNET_DISK_file_map (fh,
1225  &mh,
1227  (size_t) bytes_read);
1228  read_offset = 0;
1229  while (read_offset < (size_t) bytes_read)
1230  {
1231  const char *newline;
1232  size_t line_len;
1233 
1234  newline = strchr (buf + read_offset, '\n');
1235  if (NULL == newline)
1236  break;
1237  line_len = newline - buf - read_offset;
1238  extract_hosts (buf + read_offset, line_len);
1239  read_offset += line_len + 1;
1240  }
1243 }
1244 
1245 
1253 static void
1254 init_cb (void *cls,
1255  const struct GNUNET_CONFIGURATION_Handle *cfg,
1256  struct GNUNET_SERVICE_Handle *sh)
1257 {
1258  char **dns_servers;
1259  int num_dns_servers;
1260 
1261  (void) cfg;
1262  (void) sh;
1263  load_etc_hosts ();
1265  dnsstub_ctx = GNUNET_DNSSTUB_start (128);
1266  dns_servers = NULL;
1267  num_dns_servers = lookup_dns_servers (&dns_servers);
1268  if (0 >= num_dns_servers)
1269  {
1270  GNUNET_log (
1272  _ ("No DNS server available. DNS resolution will not be possible.\n"));
1273  return;
1274  }
1275  for (int i = 0; i < num_dns_servers; i++)
1276  {
1277  int result = GNUNET_DNSSTUB_add_dns_ip (dnsstub_ctx, dns_servers[i]);
1279  "Adding DNS server '%s': %s\n",
1280  dns_servers[i],
1281  GNUNET_OK == result ? "success" : "failure");
1282  GNUNET_free (dns_servers[i]);
1283  }
1284  GNUNET_free_non_null (dns_servers);
1285 }
1286 
1287 
1296 static void *
1297 connect_cb (void *cls,
1298  struct GNUNET_SERVICE_Client *c,
1299  struct GNUNET_MQ_Handle *mq)
1300 {
1301  (void) cls;
1302  (void) mq;
1303 
1304  return c;
1305 }
1306 
1307 
1315 static void
1316 disconnect_cb (void *cls, struct GNUNET_SERVICE_Client *c, void *internal_cls)
1317 {
1318  struct ActiveLookup *n;
1319  (void) cls;
1320 
1321  GNUNET_assert (c == internal_cls);
1322  n = lookup_head;
1323  for (struct ActiveLookup *al = n; NULL != al; al = n)
1324  {
1325  n = al->next;
1326  if (al->client == c)
1327  free_active_lookup (al);
1328  }
1329 }
1330 
1331 
1336  "resolver",
1338  &init_cb,
1339  &connect_cb,
1340  &disconnect_cb,
1341  NULL,
1342  GNUNET_MQ_hd_var_size (get,
1345  NULL),
1347 
1348 
1349 #if defined(LINUX) && defined(__GLIBC__)
1350 #include <malloc.h>
1351 
1355 void __attribute__ ((constructor)) GNUNET_RESOLVER_memory_init ()
1356 {
1357  mallopt (M_TRIM_THRESHOLD, 4 * 1024);
1358  mallopt (M_TOP_PAD, 1 * 1024);
1359  malloc_trim (0);
1360 }
1361 #endif
1362 
1363 
1364 /* end of gnunet-service-resolver.c */
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
static void load_etc_hosts(void)
Reads the list of hosts from /etc/hosts.
static char * make_reverse_hostname(const void *ip, int af)
Compute name to use for DNS reverse lookups from ip.
struct GNUNET_DNSPARSER_Record * answers
Array of all answers in the packet, must contain "num_answers" entries.
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
Open the file for reading.
static unsigned int cache_size
How many entries do we have in cache_head DLL?
static int send_reply(struct GNUNET_DNSPARSER_Record *record, uint16_t record_type, uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
Send DNS record back to our client.
int32_t direction
GNUNET_YES to get hostname from IP, GNUNET_NO to get IP from hostname.
Definition: resolver.h:54
#define memrchr(s, c, n)
Definition: compat.h:48
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
int GNUNET_DISK_file_close(struct GNUNET_DISK_FileHandle *h)
Close an open file.
Definition: disk.c:1817
static void init_cb(void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg, struct GNUNET_SERVICE_Handle *sh)
Service is starting, initialize everything.
static struct ResolveCache * hosts_tail
Tail of the linked list of DNS lookup results from /etc/hosts.
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
Definition: w32nsp.c:83
Handle to a service.
Definition: service.c:116
static int pack(const char *hostname, uint16_t type, uint16_t dns_id, char **packet_buf, size_t *packet_size)
Create DNS query for hostname of type type with DNS request ID dns_id.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
struct GNUNET_SERVICE_Client * client
The client that queried the records contained in this cache entry.
#define GNUNET_DNSPARSER_TYPE_CNAME
int GNUNET_snprintf(char *buf, size_t size, const char *format,...)
Like snprintf, just aborts if the buffer is of insufficient size.
struct GNUNET_MQ_Handle * GNUNET_SERVICE_client_get_mq(struct GNUNET_SERVICE_Client *c)
Obtain the message queue of c.
Definition: service.c:2734
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_shutdown(GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run on shutdown, that is when a CTRL-C signal is received, or when GNUNET_SCHEDULER_shutdown() is being invoked.
Definition: scheduler.c:1293
struct RecordListEntry * prev
This is a doubly linked list.
struct GNUNET_SCHEDULER_Task * timeout_task
handle for the resolution timeout task
uint32_t GNUNET_CRYPTO_random_u32(enum GNUNET_CRYPTO_Quality mode, uint32_t i)
Produce a random value.
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
void GNUNET_DNSSTUB_stop(struct GNUNET_DNSSTUB_Context *ctx)
Cleanup DNSSTUB resolver.
Definition: dnsstub.c:731
int GNUNET_DNSPARSER_pack(const struct GNUNET_DNSPARSER_Packet *p, uint16_t max, char **buf, size_t *buf_length)
Given a DNS packet p, generate the corresponding UDP payload.
Definition: dnsparser.c:1259
static struct GNUNET_CADET_Handle * mh
Cadet handle.
Definition: gnunet-cadet.c:92
void GNUNET_DNSPARSER_free_record(struct GNUNET_DNSPARSER_Record *r)
Free the given DNS record.
Definition: dnsparser.c:180
static struct GNUNET_DNSSTUB_Context * dnsstub_ctx
context of dnsstub library
static void shutdown_task(void *cls)
Service is shutting down, clean up.
static char * extract_dns_server(const char *line, size_t line_len)
Find out if the configuration file line contains a string starting with "nameserver "...
void * GNUNET_DISK_file_map(const struct GNUNET_DISK_FileHandle *h, struct GNUNET_DISK_MapHandle **m, enum GNUNET_DISK_MapType access, size_t len)
Map a file into memory.
Definition: disk.c:2020
int GNUNET_DNSSTUB_add_dns_ip(struct GNUNET_DNSSTUB_Context *ctx, const char *dns_ip)
Add nameserver for use by the DNSSTUB.
Definition: dnsstub.c:622
static void add_host(const char *hostname, uint16_t rec_type, const void *data, size_t data_size)
Add information about a host from /etc/hosts to our cache.
uint16_t id
DNS ID (to match replies to requests).
GNUNET_SERVICE_MAIN("resolver", GNUNET_SERVICE_OPTION_NONE, &init_cb, &connect_cb, &disconnect_cb, NULL, GNUNET_MQ_hd_var_size(get, GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST, struct GNUNET_RESOLVER_GetMessage, NULL), GNUNET_MQ_handler_end())
Define "main" method using service macro.
Nobody is allowed to do anything to the file.
#define GNUNET_MQ_msg(mvar, type)
Allocate a GNUNET_MQ_Envelope.
Definition: gnunet_mq_lib.h:67
static void * connect_cb(void *cls, struct GNUNET_SERVICE_Client *c, struct GNUNET_MQ_Handle *mq)
Callback called when a client connects to the service.
void GNUNET_DNSPARSER_free_packet(struct GNUNET_DNSPARSER_Packet *p)
Free memory taken by a packet.
Definition: dnsparser.c:854
#define GNUNET_NO
Definition: gnunet_common.h:81
#define GNUNET_memdup(buf, size)
Allocate and initialize a block of memory.
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:78
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
struct ResolveCache * next
This is a doubly linked list.
static void handle_resolve_result(void *cls, const struct GNUNET_TUN_DnsHeader *dns, size_t dns_len)
We got a result from DNS.
struct GNUNET_DNSPARSER_Record * additional_records
Array of all additional answers in the packet, must contain "num_additional_records" entries...
struct RecordListEntry * next
This is a doubly linked list.
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
uint32_t client_id
identifies the request this message responds to.
Definition: resolver.h:84
unsigned int num_answers
Number of answers in the packet, should be 0 for queries.
uint64_t abs_value_us
The actual value.
#define SIZE_MAX
Definition: platform.h:250
#define DNS_TIMEOUT
How long do we wait for DNS answers?
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
A cached DNS lookup result.
struct RecordListEntry * records_tail
tail of a double linked list containing the lookup results
#define GNUNET_TIME_UNIT_FOREVER_ABS
Constant used to specify "forever".
#define _(String)
GNU gettext support macro.
Definition: platform.h:208
#define GNUNET_DNSPARSER_TYPE_PTR
static unsigned int records
Number of records we found.
uint16_t dns_traffic_class
See GNUNET_TUN_DNS_CLASS_*.
Handle to a client that is connected to a service.
Definition: service.c:249
struct ActiveLookup * prev
Stored in a DLL.
struct GNUNET_DNSPARSER_Record * record
Cached data.
uint16_t dns_id
Unique DNS request ID of a client if a query for this hostname/record_type is currently pending...
static int try_cache(const char *hostname, uint16_t record_type, uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
Get an IP address as a string (works for both IPv4 and IPv6).
#define GNUNET_MQ_msg_extra(mvar, esize, type)
Allocate an envelope, with extra space allocated after the space needed by the message struct...
Definition: gnunet_mq_lib.h:52
struct GNUNET_SCHEDULER_Task * GNUNET_SCHEDULER_add_delayed(struct GNUNET_TIME_Relative delay, GNUNET_SCHEDULER_TaskCallback task, void *task_cls)
Schedule a new task to be run with a specified delay.
Definition: scheduler.c:1246
uint32_t client_request_id
Unique request ID of a client if a query for this hostname/record_type is currently pending...
#define GNUNET_MQ_check_zero_termination(m)
Insert code for a "check_" function that verifies that a given variable-length message received over ...
static struct ActiveLookup * lookup_tail
Tail of the linked list of active DNS lookups.
char * name
Name of the record that the query is for (0-terminated).
char * hostname
For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
#define GNUNET_memcpy(dst, src, n)
static char * line
Desired phone line (string to be converted to a hash).
uint16_t record_type
type of queried DNS record
unsigned int num_additional_records
Number of additional records in the packet, should be 0 for queries.
static void disconnect_cb(void *cls, struct GNUNET_SERVICE_Client *c, void *internal_cls)
Callback called when a client disconnected from the service.
struct GNUNET_DNSPARSER_Packet * GNUNET_DNSPARSER_parse(const char *udp_payload, size_t udp_payload_length)
Parse a UDP payload of a DNS packet in to a nice struct for further processing and manipulation...
Definition: dnsparser.c:662
#define GNUNET_MQ_hd_var_size(name, code, str, ctx)
struct GNUNET_DNSSTUB_Context * GNUNET_DNSSTUB_start(unsigned int num_sockets)
Start a DNS stub resolver.
Definition: dnsstub.c:595
static struct ResolveCache * hosts_head
Head of the linked list of DNS lookup results from /etc/hosts.
static struct SolverHandle * sh
static int remove_expired(struct ResolveCache *rc)
Remove expired entries from rc.
Read-only memory map.
static void free_hosts_entry(struct ResolveCache *rc)
Remove entry from cache.
int did_aaaa
If record_type is GNUNET_DNSPARSER_TYPE_ALL, did we go again for the AAAA records yet...
Randomness for IVs etc.
static char buf[2048]
#define GNUNET_new_array(n, type)
Allocate a size n array with structs or unions of the given type.
static struct ResolveCache * cache_tail
Tail of the linked list of cached DNS lookup results.
unsigned int recursion_desired
Set to 1 if recursion is desired (client -> server)
static int result
Global testing status.
#define GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE
Response to a DNS resolution request.
static void handle_resolve_timeout(void *cls)
We encountered a timeout trying to perform a DNS lookup.
static int fh
Handle to the unique file.
A DNS response record.
static char * extract_search_domain(const char *line, size_t line_len)
Find out if the configuration file line contains a string starting with "search ", and if so, return a copy of the machine&#39;s search domain.
Information about pending lookups.
struct GNUNET_DNSPARSER_Record * authority_records
Array of all authority records in the packet, must contain "num_authority_records" entries...
static int resolve_and_cache(const char *hostname, uint16_t record_type, uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
Initiate an active lookup, then cache the result and try to then complete the resolution.
struct GNUNET_DNSPARSER_Record * GNUNET_DNSPARSER_duplicate_record(const struct GNUNET_DNSPARSER_Record *r)
Duplicate (deep-copy) the given DNS record.
Definition: dnsparser.c:743
void GNUNET_SERVICE_client_drop(struct GNUNET_SERVICE_Client *c)
Ask the server to disconnect from the given client.
Definition: service.c:2618
Handle to the stub resolver.
Definition: dnsstub.c:125
struct GNUNET_DNSPARSER_Query * queries
Array of all queries in the packet, must contain "num_queries" entries.
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get(void)
Get the current time.
Definition: time.c:118
static void process_get(const char *hostname, uint16_t record_type, uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
Process DNS request for hostname with request ID request_id from client demanding records of type rec...
static void cache_answers(const char *name, struct GNUNET_DNSPARSER_Record *records, unsigned int num_records)
struct GNUNET_DNSSTUB_RequestSocket * GNUNET_DNSSTUB_resolve(struct GNUNET_DNSSTUB_Context *ctx, const void *request, size_t request_len, GNUNET_DNSSTUB_ResultCallback rc, void *rc_cls)
Perform DNS resolution using our default IP from init.
Definition: dnsstub.c:533
static struct GNUNET_CONFIGURATION_Handle * cfg
Our configuration.
Definition: gnunet-arm.c:104
#define GNUNET_SYSERR
Definition: gnunet_common.h:79
static struct ResolveCache * cache_head
Start of the linked list of cached DNS lookup results.
static unsigned int size
Size of the "table".
Definition: peer.c:67
size_t data_len
Number of bytes in data.
int GNUNET_DISK_file_unmap(struct GNUNET_DISK_MapHandle *h)
Unmap a file.
Definition: disk.c:2100
static int check_get(void *cls, const struct GNUNET_RESOLVER_GetMessage *get)
Verify well-formedness of GET-message.
void * data
Binary record data.
const char * name
struct ResolveCache * prev
This is a doubly linked list.
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
unsigned int num_authority_records
Number of authoritative answers in the packet, should be 0 for queries.
static unsigned long long payload
How much data are we currently storing in the database?
#define GNUNET_TUN_DNS_CLASS_INTERNET
A few common DNS classes (ok, only one is common, but I list a couple more to make it clear what we&#39;r...
static void handle_get(void *cls, const struct GNUNET_RESOLVER_GetMessage *msg)
Handle GET-message.
static struct ActiveLookup * lookup_head
Start of the linked list of active DNS lookups.
Handle to a message queue.
Definition: mq.c:85
struct GNUNET_TIME_Absolute expiration_time
When does the record expire?
int32_t af
Address family to use (AF_INET, AF_INET6 or AF_UNSPEC).
Definition: resolver.h:59
#define GNUNET_strndup(a, length)
Wrapper around GNUNET_xstrndup_.
#define GNUNET_array_append(arr, size, element)
Append an element to a list (growing the list by one).
static void free_cache_entry(struct ResolveCache *rc)
Remove entry from cache.
enum RadiotapType __attribute__
static char * hostname
Our hostname; we give this to all the peers we start.
#define GNUNET_DNSPARSER_TYPE_AAAA
configuration data
Definition: configuration.c:85
void GNUNET_DNSSTUB_resolve_cancel(struct GNUNET_DNSSTUB_RequestSocket *rs)
Cancel DNS resolution.
Definition: dnsstub.c:571
#define GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST
Request DNS resolution.
uint32_t client_id
identifies the request and is contained in the response message.
Definition: resolver.h:65
Easy-to-process, parsed version of a DNS packet.
struct GNUNET_DNSSTUB_RequestSocket * resolve_handle
handle for cancelling a request
int GNUNET_DISK_file_handle_size(struct GNUNET_DISK_FileHandle *fh, off_t *size)
Get the size of an open file.
Definition: disk.c:208
struct GNUNET_MQ_Handle * mq
Definition: 003.c:5
static int inet_pton(int af, const char *cp, struct in_addr *buf)
Convert IPv4 address from text to binary form.
#define GNUNET_log(kind,...)
Entry in list of pending tasks.
Definition: scheduler.c:134
static void send_end_msg(uint32_t client_request_id, struct GNUNET_SERVICE_Client *client)
Send message to client that we transmitted all responses for client_request_id.
static int lookup_dns_servers(char ***server_addrs)
Reads the list of nameservers from /etc/resolve.conf.
uint16_t dns_traffic_class
See GNUNET_TUN_DNS_CLASS_*.
char * name
Name of the record that the query is for (0-terminated).
unsigned int num_queries
Number of queries in the packet.
char * hostname
Which hostname is this cache for?
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model
Time for absolute times used by GNUnet, in microseconds.
#define GNUNET_YES
Definition: gnunet_common.h:80
void GNUNET_MQ_send(struct GNUNET_MQ_Handle *mq, struct GNUNET_MQ_Envelope *ev)
Send a message with the given message queue.
Definition: mq.c:353
static void extract_hosts(const char *line, size_t line_len)
Extract host information from a line in /etc/hosts.
union GNUNET_DNSPARSER_Record::@27 data
Payload of the record (which one of these is valid depends on the &#39;type&#39;).
struct GNUNET_TUN_DnsFlags flags
Bitfield of DNS flags.
Request for the resolver.
Definition: resolver.h:43
UDP socket we are using for sending DNS requests to the Internet.
Definition: dnsstub.c:43
struct ActiveLookup * next
Stored in a DLL.
uint32_t data
The data value.
struct GNUNET_DISK_FileHandle * GNUNET_DISK_file_open(const char *fn, enum GNUNET_DISK_OpenFlags flags, enum GNUNET_DISK_AccessPermissions perm)
Open a file.
Definition: disk.c:1673
static void free_active_lookup(struct ActiveLookup *al)
Release resources associated with al.
static size_t data_size
Number of bytes in data.
Entry in list of cached DNS records for a hostname.
#define GNUNET_DNSPARSER_TYPE_ALL
struct GNUNET_DNSPARSER_RawRecord raw
Raw data for all other types.
#define GNUNET_DNSPARSER_TYPE_A
Handle used to access files (and pipes).
void GNUNET_SERVICE_client_continue(struct GNUNET_SERVICE_Client *c)
Continue receiving further messages from the given client.
Definition: service.c:2533
char * hostname
Which hostname are we resolving?
#define GNUNET_MQ_handler_end()
End-marker for the handlers array.
#define GNUNET_malloc(size)
Wrapper around malloc.
#define MAX_CACHE
Maximum number of hostnames we cache results for.
Handle for a memory-mapping operation.
Definition: disk.c:1985
#define GNUNET_free(ptr)
Wrapper around free.
static char * my_domain
My domain, to be appended to the hostname to get a FQDN.
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:965