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3 Copyright (C) 2007-2016 GNUnet e.V.
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
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13 Affero General Public License for more details.
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20 * @file util/gnunet-service-resolver.c
21 * @brief code to do DNS resolution
22 * @author Christian Grothoff
25 #include "gnunet_util_lib.h"
26 #include "gnunet_protocols.h"
27 #include "gnunet_statistics_service.h"
32 * How long do we wait for DNS answers?
34 #define DNS_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
37 * Maximum number of hostnames we cache results for.
39 #define MAX_CACHE 1024
42 * Entry in list of cached DNS records for a hostname.
44 struct RecordListEntry
47 * This is a doubly linked list.
49 struct RecordListEntry *next;
52 * This is a doubly linked list.
54 struct RecordListEntry *prev;
59 struct GNUNET_DNSPARSER_Record *record;
65 * A cached DNS lookup result.
70 * This is a doubly linked list.
72 struct ResolveCache *next;
75 * This is a doubly linked list.
77 struct ResolveCache *prev;
80 * Which hostname is this cache for?
85 * head of a double linked list containing the lookup results
87 struct RecordListEntry *records_head;
90 * tail of a double linked list containing the lookup results
92 struct RecordListEntry *records_tail;
98 * Information about pending lookups.
105 struct ActiveLookup *next;
110 struct ActiveLookup *prev;
113 * The client that queried the records contained in this cache entry.
115 struct GNUNET_SERVICE_Client *client;
118 * handle for cancelling a request
120 struct GNUNET_DNSSTUB_RequestSocket *resolve_handle;
123 * handle for the resolution timeout task
125 struct GNUNET_SCHEDULER_Task *timeout_task;
128 * Which hostname are we resolving?
133 * If @a record_type is #GNUNET_DNSPARSER_TYPE_ALL, did we go again
134 * for the AAAA records yet?
139 * type of queried DNS record
141 uint16_t record_type;
144 * Unique request ID of a client if a query for this hostname/record_type
145 * is currently pending, undefined otherwise.
147 uint32_t client_request_id;
150 * Unique DNS request ID of a client if a query for this hostname/record_type
151 * is currently pending, undefined otherwise.
159 * Start of the linked list of cached DNS lookup results.
161 static struct ResolveCache *cache_head;
164 * Tail of the linked list of cached DNS lookup results.
166 static struct ResolveCache *cache_tail;
169 * Head of the linked list of DNS lookup results from /etc/hosts.
171 static struct ResolveCache *hosts_head;
174 * Tail of the linked list of DNS lookup results from /etc/hosts.
176 static struct ResolveCache *hosts_tail;
179 * Start of the linked list of active DNS lookups.
181 static struct ActiveLookup *lookup_head;
184 * Tail of the linked list of active DNS lookups.
186 static struct ActiveLookup *lookup_tail;
189 * context of dnsstub library
191 static struct GNUNET_DNSSTUB_Context *dnsstub_ctx;
194 * My domain, to be appended to the hostname to get a FQDN.
196 static char *my_domain;
199 * How many entries do we have in #cache_head DLL?
201 static unsigned int cache_size;
205 * Remove @a entry from cache.
207 * @param rc entry to free
210 free_cache_entry (struct ResolveCache *rc)
212 struct RecordListEntry *pos;
214 while (NULL != (pos = rc->records_head))
216 GNUNET_CONTAINER_DLL_remove (rc->records_head,
219 GNUNET_DNSPARSER_free_record (pos->record);
220 GNUNET_free (pos->record);
223 GNUNET_free_non_null (rc->hostname);
224 GNUNET_CONTAINER_DLL_remove (cache_head,
233 * Remove @a entry from cache.
235 * @param rc entry to free
238 free_hosts_entry (struct ResolveCache *rc)
240 struct RecordListEntry *pos;
242 while (NULL != (pos = rc->records_head))
244 GNUNET_CONTAINER_DLL_remove (rc->records_head,
247 GNUNET_DNSPARSER_free_record (pos->record);
248 GNUNET_free (pos->record);
251 GNUNET_free_non_null (rc->hostname);
252 GNUNET_CONTAINER_DLL_remove (hosts_head,
261 * Release resources associated with @a al
263 * @param al an active lookup
266 free_active_lookup (struct ActiveLookup *al)
268 GNUNET_CONTAINER_DLL_remove (lookup_head,
271 if (NULL != al->resolve_handle)
273 GNUNET_DNSSTUB_resolve_cancel (al->resolve_handle);
274 al->resolve_handle = NULL;
276 if (NULL != al->timeout_task)
278 GNUNET_SCHEDULER_cancel (al->timeout_task);
279 al->timeout_task = NULL;
281 GNUNET_free_non_null (al->hostname);
288 * Find out if the configuration file line contains a string
289 * starting with "nameserver ", and if so, return a copy of
290 * the nameserver's IP.
292 * @param line line to parse
293 * @param line_len number of characters in @a line
294 * @return NULL if no nameserver is configured in this @a line
297 extract_dns_server (const char* line,
300 if (0 == strncmp (line,
302 strlen ("nameserver ")))
303 return GNUNET_strndup (line + strlen ("nameserver "),
304 line_len - strlen ("nameserver "));
310 * Find out if the configuration file line contains a string
311 * starting with "search ", and if so, return a copy of
312 * the machine's search domain.
314 * @param line line to parse
315 * @param line_len number of characters in @a line
316 * @return NULL if no nameserver is configured in this @a line
319 extract_search_domain (const char* line,
322 if (0 == strncmp (line,
325 return GNUNET_strndup (line + strlen ("search "),
326 line_len - strlen ("search "));
332 * Reads the list of nameservers from /etc/resolve.conf
334 * @param server_addrs[out] a list of null-terminated server address strings
335 * @return the number of server addresses in @server_addrs, -1 on error
338 lookup_dns_servers (char ***server_addrs)
340 struct GNUNET_DISK_FileHandle *fh;
341 struct GNUNET_DISK_MapHandle *mh;
345 unsigned int num_dns_servers;
347 fh = GNUNET_DISK_file_open ("/etc/resolv.conf",
348 GNUNET_DISK_OPEN_READ,
349 GNUNET_DISK_PERM_NONE);
352 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
353 "Could not open /etc/resolv.conf. "
354 "DNS resolution will not be possible.\n");
358 GNUNET_DISK_file_handle_size (fh,
361 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
362 "Could not determine size of /etc/resolv.conf. "
363 "DNS resolution will not be possible.\n");
364 GNUNET_DISK_file_close (fh);
367 if (bytes_read > SIZE_MAX)
369 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
370 "/etc/resolv.conf file too large to mmap. "
371 "DNS resolution will not be possible.\n");
372 GNUNET_DISK_file_close (fh);
375 buf = GNUNET_DISK_file_map (fh,
377 GNUNET_DISK_MAP_TYPE_READ,
378 (size_t) bytes_read);
379 *server_addrs = NULL;
382 while (read_offset < bytes_read)
388 newline = strchr (buf + read_offset,
392 line_len = newline - buf - read_offset;
393 dns_server = extract_dns_server (buf + read_offset,
395 if (NULL != dns_server)
397 GNUNET_array_append (*server_addrs,
401 else if (NULL == my_domain)
403 my_domain = extract_search_domain (buf + read_offset,
406 read_offset += line_len + 1;
408 GNUNET_DISK_file_unmap (mh);
409 GNUNET_DISK_file_close (fh);
410 return (int) num_dns_servers;
415 * Compute name to use for DNS reverse lookups from @a ip.
417 * @param ip IP address to resolve, in binary format, network byte order
418 * @param af address family of @a ip, AF_INET or AF_INET6
421 make_reverse_hostname (const void *ip,
424 char *buf = GNUNET_new_array (80,
430 struct in_addr *addr = (struct in_addr *)ip;
431 uint32_t ip_int = addr->s_addr;
433 for (int i = 3; i >= 0; i--)
435 int n = GNUNET_snprintf (buf + pos,
438 ((uint8_t *)&ip_int)[i]);
446 pos += GNUNET_snprintf (buf + pos,
450 else if (AF_INET6 == af)
452 struct in6_addr *addr = (struct in6_addr *)ip;
453 for (int i = 15; i >= 0; i--)
455 int n = GNUNET_snprintf (buf + pos,
458 addr->s6_addr[i] & 0xf);
465 n = GNUNET_snprintf (buf + pos,
468 addr->s6_addr[i] >> 4);
476 pos += GNUNET_snprintf (buf + pos,
486 * Send DNS @a record back to our @a client.
488 * @param record information to transmit
489 * @param record_type requested record type from client
490 * @param client_request_id to which request are we responding
491 * @param client where to send @a record
492 * @return #GNUNET_YES if we sent a reply,
493 * #GNUNET_NO if the record type is not understood or
494 * does not match @a record_type
497 send_reply (struct GNUNET_DNSPARSER_Record *record,
498 uint16_t record_type,
499 uint32_t client_request_id,
500 struct GNUNET_SERVICE_Client *client)
502 struct GNUNET_RESOLVER_ResponseMessage *msg;
503 struct GNUNET_MQ_Envelope *env;
507 switch (record->type)
509 case GNUNET_DNSPARSER_TYPE_CNAME:
510 if (GNUNET_DNSPARSER_TYPE_CNAME != record_type)
512 payload = record->data.hostname;
513 payload_len = strlen (record->data.hostname) + 1;
515 case GNUNET_DNSPARSER_TYPE_PTR:
516 if (GNUNET_DNSPARSER_TYPE_PTR != record_type)
518 payload = record->data.hostname;
519 payload_len = strlen (record->data.hostname) + 1;
521 case GNUNET_DNSPARSER_TYPE_A:
522 if ( (GNUNET_DNSPARSER_TYPE_A != record_type) &&
523 (GNUNET_DNSPARSER_TYPE_ALL != record_type) )
525 payload = record->data.raw.data;
526 payload_len = record->data.raw.data_len;
528 case GNUNET_DNSPARSER_TYPE_AAAA:
529 if ( (GNUNET_DNSPARSER_TYPE_AAAA != record_type) &&
530 (GNUNET_DNSPARSER_TYPE_ALL != record_type) )
532 payload = record->data.raw.data;
533 payload_len = record->data.raw.data_len;
536 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
537 "Cannot handle DNS response type %u: not supported here\n",
541 env = GNUNET_MQ_msg_extra (msg,
543 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
544 msg->client_id = client_request_id;
545 GNUNET_memcpy (&msg[1],
548 GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client),
555 * Send message to @a client that we transmitted all
556 * responses for @a client_request_id
558 * @param client_request_id to which request are we responding
559 * @param client where to send @a record
562 send_end_msg (uint32_t client_request_id,
563 struct GNUNET_SERVICE_Client *client)
565 struct GNUNET_RESOLVER_ResponseMessage *msg;
566 struct GNUNET_MQ_Envelope *env;
568 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
569 "Sending END message\n");
570 env = GNUNET_MQ_msg (msg,
571 GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE);
572 msg->client_id = client_request_id;
573 GNUNET_MQ_send (GNUNET_SERVICE_client_get_mq (client),
579 * Remove expired entries from @a rc
581 * @param rc entry in resolver cache
582 * @return #GNUNET_YES if @a rc was completely expired
583 * #GNUNET_NO if some entries are left
586 remove_expired (struct ResolveCache *rc)
588 struct GNUNET_TIME_Absolute now = GNUNET_TIME_absolute_get ();
589 struct RecordListEntry *n;
591 for (struct RecordListEntry *pos = rc->records_head;
596 if (now.abs_value_us > pos->record->expiration_time.abs_value_us)
598 GNUNET_CONTAINER_DLL_remove (rc->records_head,
601 GNUNET_DNSPARSER_free_record (pos->record);
602 GNUNET_free (pos->record);
606 if (NULL == rc->records_head)
608 free_cache_entry (rc);
616 * Process DNS request for @a hostname with request ID @a request_id
617 * from @a client demanding records of type @a record_type.
619 * @param hostname DNS name to resolve
620 * @param record_type desired record type
621 * @param client_request_id client's request ID
622 * @param client who should get the result?
625 process_get (const char *hostname,
626 uint16_t record_type,
627 uint32_t client_request_id,
628 struct GNUNET_SERVICE_Client *client);
632 * Get an IP address as a string (works for both IPv4 and IPv6). Note
633 * that the resolution happens asynchronously and that the first call
634 * may not immediately result in the FQN (but instead in a
635 * human-readable IP address).
637 * @param hostname what hostname was to be resolved
638 * @param record_type what type of record was requested
639 * @param client_request_id unique identification of the client's request
640 * @param client handle to the client making the request (for sending the reply)
643 try_cache (const char *hostname,
644 uint16_t record_type,
645 uint32_t client_request_id,
646 struct GNUNET_SERVICE_Client *client)
648 struct ResolveCache *pos;
649 struct ResolveCache *next;
652 for (pos = hosts_head; NULL != pos; pos = pos->next)
653 if (0 == strcmp (pos->hostname,
659 for (pos = next; NULL != pos; pos = next)
662 if (GNUNET_YES == remove_expired (pos))
664 if (0 == strcmp (pos->hostname,
671 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
672 "No cache entry for '%s'\n",
676 if (cache_head != pos)
678 /* move result to head to achieve LRU for cache eviction */
679 GNUNET_CONTAINER_DLL_remove (cache_head,
682 GNUNET_CONTAINER_DLL_insert (cache_head,
687 for (struct RecordListEntry *rle = pos->records_head;
691 const struct GNUNET_DNSPARSER_Record *record = rle->record;
693 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
694 "Found cache entry for '%s', record type '%u'\n",
697 if ( (GNUNET_DNSPARSER_TYPE_CNAME == record->type) &&
698 (GNUNET_DNSPARSER_TYPE_CNAME != record_type) &&
699 (GNUNET_NO == found) )
701 const char *hostname = record->data.hostname;
703 process_get (hostname,
707 return GNUNET_YES; /* counts as a cache "hit" */
709 found |= send_reply (rle->record,
714 if (GNUNET_NO == found)
715 return GNUNET_NO; /* had records, but none matched! */
716 send_end_msg (client_request_id,
723 * Create DNS query for @a hostname of type @a type
724 * with DNS request ID @a dns_id.
726 * @param hostname DNS name to query
727 * @param type requested DNS record type
728 * @param dns_id what should be the DNS request ID
729 * @param packet_buf[out] where to write the request packet
730 * @param packet_size[out] set to size of @a packet_buf on success
731 * @return #GNUNET_OK on success
734 pack (const char *hostname,
740 struct GNUNET_DNSPARSER_Query query;
741 struct GNUNET_DNSPARSER_Packet packet;
743 query.name = (char *)hostname;
745 query.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
749 packet.num_queries = 1;
750 packet.queries = &query;
751 packet.id = htons (dns_id);
752 packet.flags.recursion_desired = 1;
754 GNUNET_DNSPARSER_pack (&packet,
759 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
760 "Failed to pack query for hostname `%s'\n",
763 return GNUNET_SYSERR;
770 * We got a result from DNS. Add it to the cache and
771 * see if we can make our client happy...
773 * @param cls the `struct ActiveLookup`
774 * @param dns the DNS response
775 * @param dns_len number of bytes in @a dns
778 handle_resolve_result (void *cls,
779 const struct GNUNET_TUN_DnsHeader *dns,
782 struct ActiveLookup *al = cls;
783 struct GNUNET_DNSPARSER_Packet *parsed;
784 struct ResolveCache *rc;
786 parsed = GNUNET_DNSPARSER_parse ((const char *)dns,
790 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
791 "Failed to parse DNS reply (hostname %s, request ID %u)\n",
796 if (al->dns_id != ntohs (parsed->id))
798 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
799 "Request ID in DNS reply does not match\n");
800 GNUNET_DNSPARSER_free_packet (parsed);
803 if (0 == parsed->num_answers + parsed->num_authority_records + parsed->num_additional_records)
805 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
806 "DNS reply (hostname %s, request ID %u) contains no answers\n",
808 (unsigned int) al->client_request_id);
809 GNUNET_DNSPARSER_free_packet (parsed);
810 send_end_msg (al->client_request_id,
812 free_active_lookup (al);
815 /* LRU-based cache eviction: we remove from tail */
816 while (cache_size > MAX_CACHE)
817 free_cache_entry (cache_tail);
819 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
820 "Got reply for hostname %s and request ID %u\n",
822 (unsigned int) al->client_request_id);
824 for (unsigned int i = 0; i != parsed->num_answers; i++)
826 struct GNUNET_DNSPARSER_Record *record = &parsed->answers[i];
827 struct RecordListEntry *rle;
829 for (rc = cache_head; NULL != rc; rc = rc->next)
830 if (0 == strcasecmp (rc->hostname,
835 rc = GNUNET_new (struct ResolveCache);
836 rc->hostname = GNUNET_strdup (record->name);
837 GNUNET_CONTAINER_DLL_insert (cache_head,
842 /* TODO: ought to check first if we have this exact record
843 already in the cache! */
844 rle = GNUNET_new (struct RecordListEntry);
845 rle->record = GNUNET_DNSPARSER_duplicate_record (record);
846 GNUNET_CONTAINER_DLL_insert (rc->records_head,
850 for (unsigned int i = 0; i != parsed->num_authority_records; i++)
852 struct GNUNET_DNSPARSER_Record *record = &parsed->authority_records[i];
853 struct RecordListEntry *rle;
855 for (rc = cache_head; NULL != rc; rc = rc->next)
856 if (0 == strcasecmp (rc->hostname,
861 rc = GNUNET_new (struct ResolveCache);
862 rc->hostname = GNUNET_strdup (record->name);
863 GNUNET_CONTAINER_DLL_insert (cache_head,
868 /* TODO: ought to check first if we have this exact record
869 already in the cache! */
870 rle = GNUNET_new (struct RecordListEntry);
871 rle->record = GNUNET_DNSPARSER_duplicate_record (record);
872 GNUNET_CONTAINER_DLL_insert (rc->records_head,
876 for (unsigned int i = 0; i != parsed->num_additional_records; i++)
878 struct GNUNET_DNSPARSER_Record *record = &parsed->additional_records[i];
879 struct RecordListEntry *rle;
881 for (rc = cache_head; NULL != rc; rc = rc->next)
882 if (0 == strcasecmp (rc->hostname,
887 rc = GNUNET_new (struct ResolveCache);
888 rc->hostname = GNUNET_strdup (record->name);
889 GNUNET_CONTAINER_DLL_insert (cache_head,
894 /* TODO: ought to check first if we have this exact record
895 already in the cache! */
896 rle = GNUNET_new (struct RecordListEntry);
897 rle->record = GNUNET_DNSPARSER_duplicate_record (record);
898 GNUNET_CONTAINER_DLL_insert (rc->records_head,
902 /* see if we need to do the 2nd request for AAAA records */
903 if ( (GNUNET_DNSPARSER_TYPE_ALL == al->record_type) &&
904 (GNUNET_NO == al->did_aaaa) )
910 dns_id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
914 GNUNET_DNSPARSER_TYPE_AAAA,
919 al->did_aaaa = GNUNET_YES;
921 GNUNET_DNSSTUB_resolve_cancel (al->resolve_handle);
923 GNUNET_DNSSTUB_resolve (dnsstub_ctx,
926 &handle_resolve_result,
928 GNUNET_free (packet_buf);
929 GNUNET_DNSPARSER_free_packet (parsed);
934 /* resume by trying again from cache */
936 try_cache (al->hostname,
938 al->client_request_id,
940 /* cache failed, tell client we could not get an answer */
942 send_end_msg (al->client_request_id,
945 free_active_lookup (al);
946 GNUNET_DNSPARSER_free_packet (parsed);
951 * We encountered a timeout trying to perform a
954 * @param cls a `struct ActiveLookup`
957 handle_resolve_timeout (void *cls)
959 struct ActiveLookup *al = cls;
961 al->timeout_task = NULL;
962 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
963 "DNS lookup timeout!\n");
964 send_end_msg (al->client_request_id,
966 free_active_lookup (al);
971 * Initiate an active lookup, then cache the result and
972 * try to then complete the resolution.
974 * @param hostname DNS name to resolve
975 * @param record_type record type to locate
976 * @param client_request_id client request ID
977 * @param client handle to the client
978 * @return #GNUNET_OK if the DNS query is now pending
981 resolve_and_cache (const char* hostname,
982 uint16_t record_type,
983 uint32_t client_request_id,
984 struct GNUNET_SERVICE_Client *client)
988 struct ActiveLookup *al;
992 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
993 "resolve_and_cache `%s'\n",
995 dns_id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
998 if (GNUNET_DNSPARSER_TYPE_ALL == record_type)
999 type = GNUNET_DNSPARSER_TYPE_A;
1009 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1010 "Failed to pack query for hostname `%s'\n",
1012 return GNUNET_SYSERR;
1015 al = GNUNET_new (struct ActiveLookup);
1016 al->hostname = GNUNET_strdup (hostname);
1017 al->record_type = record_type;
1018 al->client_request_id = client_request_id;
1019 al->dns_id = dns_id;
1020 al->client = client;
1021 al->timeout_task = GNUNET_SCHEDULER_add_delayed (DNS_TIMEOUT,
1022 &handle_resolve_timeout,
1024 al->resolve_handle =
1025 GNUNET_DNSSTUB_resolve (dnsstub_ctx,
1028 &handle_resolve_result,
1030 GNUNET_free (packet_buf);
1031 GNUNET_CONTAINER_DLL_insert (lookup_head,
1034 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1035 "Resolving %s, client_request_id = %u, dns_id = %u\n",
1037 (unsigned int) client_request_id,
1038 (unsigned int) dns_id);
1044 * Process DNS request for @a hostname with request ID @a client_request_id
1045 * from @a client demanding records of type @a record_type.
1047 * @param hostname DNS name to resolve
1048 * @param record_type desired record type
1049 * @param client_request_id client's request ID
1050 * @param client who should get the result?
1053 process_get (const char *hostname,
1054 uint16_t record_type,
1055 uint32_t client_request_id,
1056 struct GNUNET_SERVICE_Client *client)
1060 if ( (NULL != my_domain) &&
1061 (NULL == strchr (hostname,
1062 (unsigned char) '.')) &&
1063 (strlen (hostname) + strlen (my_domain) <= 253) )
1065 GNUNET_snprintf (fqdn,
1071 else if (strlen (hostname) < 255)
1073 GNUNET_snprintf (fqdn,
1081 GNUNET_SERVICE_client_drop (client);
1091 resolve_and_cache (fqdn,
1096 send_end_msg (client_request_id,
1104 * Verify well-formedness of GET-message.
1106 * @param cls closure, unused
1107 * @param get the actual message
1108 * @return #GNUNET_OK if @a get is well-formed
1111 check_get (void *cls,
1112 const struct GNUNET_RESOLVER_GetMessage *get)
1119 size = ntohs (get->header.size) - sizeof (*get);
1120 direction = ntohl (get->direction);
1121 if (GNUNET_NO == direction)
1123 /* IP from hostname */
1124 const char *hostname;
1126 hostname = (const char *) &get[1];
1127 if (hostname[size - 1] != '\0')
1130 return GNUNET_SYSERR;
1134 af = ntohl (get->af);
1138 if (size != sizeof (struct in_addr))
1141 return GNUNET_SYSERR;
1145 if (size != sizeof (struct in6_addr))
1148 return GNUNET_SYSERR;
1153 return GNUNET_SYSERR;
1160 * Handle GET-message.
1162 * @param cls identification of the client
1163 * @param msg the actual message
1166 handle_get (void *cls,
1167 const struct GNUNET_RESOLVER_GetMessage *msg)
1169 struct GNUNET_SERVICE_Client *client = cls;
1172 uint32_t client_request_id;
1175 direction = ntohl (msg->direction);
1176 af = ntohl (msg->af);
1177 client_request_id = msg->client_id;
1178 GNUNET_SERVICE_client_continue (client);
1179 if (GNUNET_NO == direction)
1181 /* IP from hostname */
1182 hostname = GNUNET_strdup ((const char *) &msg[1]);
1187 process_get (hostname,
1188 GNUNET_DNSPARSER_TYPE_ALL,
1195 process_get (hostname,
1196 GNUNET_DNSPARSER_TYPE_A,
1203 process_get (hostname,
1204 GNUNET_DNSPARSER_TYPE_AAAA,
1211 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1212 "got invalid af: %d\n",
1220 /* hostname from IP */
1221 hostname = make_reverse_hostname (&msg[1],
1223 process_get (hostname,
1224 GNUNET_DNSPARSER_TYPE_PTR,
1228 GNUNET_free_non_null (hostname);
1233 * Service is shutting down, clean up.
1235 * @param cls NULL, unused
1238 shutdown_task (void *cls)
1242 while (NULL != lookup_head)
1243 free_active_lookup (lookup_head);
1244 while (NULL != cache_head)
1245 free_cache_entry (cache_head);
1246 while (NULL != hosts_head)
1247 free_hosts_entry (hosts_head);
1248 GNUNET_DNSSTUB_stop (dnsstub_ctx);
1249 GNUNET_free (my_domain);
1254 * Add information about a host from /etc/hosts
1257 * @param hostname the name of the host
1258 * @param rec_type DNS record type to use
1259 * @param data payload
1260 * @param data_size number of bytes in @a data
1263 add_host (const char *hostname,
1268 struct ResolveCache *rc;
1269 struct RecordListEntry *rle;
1270 struct GNUNET_DNSPARSER_Record *rec;
1272 rec = GNUNET_malloc (sizeof (struct GNUNET_DNSPARSER_Record));
1273 rec->expiration_time = GNUNET_TIME_UNIT_FOREVER_ABS;
1274 rec->type = rec_type;
1275 rec->dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
1276 rec->name = GNUNET_strdup (hostname);
1277 rec->data.raw.data = GNUNET_memdup (data,
1279 rec->data.raw.data_len = data_size;
1280 rle = GNUNET_new (struct RecordListEntry);
1282 rc = GNUNET_new (struct ResolveCache);
1283 rc->hostname = GNUNET_strdup (hostname);
1284 GNUNET_CONTAINER_DLL_insert (rc->records_head,
1287 GNUNET_CONTAINER_DLL_insert (hosts_head,
1294 * Extract host information from a line in /etc/hosts
1296 * @param line the line to parse
1297 * @param line_len number of bytes in @a line
1300 extract_hosts (const char *line,
1309 /* ignore everything after '#' */
1311 (unsigned char) '#',
1314 line_len = c - line;
1315 /* ignore leading whitespace */
1316 while ( (0 > line_len) &&
1317 isspace ((unsigned char) *line) )
1322 tbuf = GNUNET_strndup (line,
1324 tok = strtok (tbuf, " \t");
1330 if (1 == inet_pton (AF_INET,
1334 while (NULL != (tok = strtok (NULL, " \t")))
1336 GNUNET_DNSPARSER_TYPE_A,
1338 sizeof (struct in_addr));
1340 else if (1 == inet_pton (AF_INET6,
1344 while (NULL != (tok = strtok (NULL, " \t")))
1346 GNUNET_DNSPARSER_TYPE_AAAA,
1348 sizeof (struct in6_addr));
1355 * Reads the list of hosts from /etc/hosts.
1358 load_etc_hosts (void)
1360 struct GNUNET_DISK_FileHandle *fh;
1361 struct GNUNET_DISK_MapHandle *mh;
1366 fh = GNUNET_DISK_file_open ("/etc/hosts",
1367 GNUNET_DISK_OPEN_READ,
1368 GNUNET_DISK_PERM_NONE);
1371 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
1372 "Failed to open /etc/hosts");
1376 GNUNET_DISK_file_handle_size (fh,
1379 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1380 "Could not determin size of /etc/hosts. "
1381 "DNS resolution will not be possible.\n");
1382 GNUNET_DISK_file_close (fh);
1385 if (bytes_read > SIZE_MAX)
1387 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1388 "/etc/hosts file too large to mmap. "
1389 "DNS resolution will not be possible.\n");
1390 GNUNET_DISK_file_close (fh);
1393 buf = GNUNET_DISK_file_map (fh,
1395 GNUNET_DISK_MAP_TYPE_READ,
1396 (size_t) bytes_read);
1398 while (read_offset < bytes_read)
1400 const char *newline;
1403 newline = strchr (buf + read_offset,
1405 if (NULL == newline)
1407 line_len = newline - buf - read_offset;
1408 extract_hosts (buf + read_offset,
1410 read_offset += line_len + 1;
1412 GNUNET_DISK_file_unmap (mh);
1413 GNUNET_DISK_file_close (fh);
1418 * Service is starting, initialize everything.
1420 * @param cls NULL, unused
1421 * @param cfg our configuration
1422 * @param sh service handle
1426 const struct GNUNET_CONFIGURATION_Handle *cfg,
1427 struct GNUNET_SERVICE_Handle *sh)
1430 int num_dns_servers;
1435 GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
1437 dnsstub_ctx = GNUNET_DNSSTUB_start (128);
1439 num_dns_servers = lookup_dns_servers (&dns_servers);
1440 if (0 >= num_dns_servers)
1442 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1443 _("No DNS server available. DNS resolution will not be possible.\n"));
1446 for (int i = 0; i < num_dns_servers; i++)
1448 int result = GNUNET_DNSSTUB_add_dns_ip (dnsstub_ctx, dns_servers[i]);
1449 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1450 "Adding DNS server '%s': %s\n",
1452 GNUNET_OK == result ? "success" : "failure");
1453 GNUNET_free (dns_servers[i]);
1455 GNUNET_free_non_null (dns_servers);
1460 * Callback called when a client connects to the service.
1462 * @param cls closure for the service, unused
1463 * @param c the new client that connected to the service
1464 * @param mq the message queue used to send messages to the client
1468 connect_cb (void *cls,
1469 struct GNUNET_SERVICE_Client *c,
1470 struct GNUNET_MQ_Handle *mq)
1480 * Callback called when a client disconnected from the service
1482 * @param cls closure for the service
1483 * @param c the client that disconnected
1484 * @param internal_cls should be equal to @a c
1487 disconnect_cb (void *cls,
1488 struct GNUNET_SERVICE_Client *c,
1491 struct ActiveLookup *n;
1494 GNUNET_assert (c == internal_cls);
1496 for (struct ActiveLookup *al = n;
1501 if (al->client == c)
1502 free_active_lookup (al);
1508 * Define "main" method using service macro.
1512 GNUNET_SERVICE_OPTION_NONE,
1517 GNUNET_MQ_hd_var_size (get,
1518 GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST,
1519 struct GNUNET_RESOLVER_GetMessage,
1521 GNUNET_MQ_handler_end ());
1524 #if defined(LINUX) && defined(__GLIBC__)
1528 * MINIMIZE heap size (way below 128k) since this process doesn't need much.
1530 void __attribute__ ((constructor))
1531 GNUNET_RESOLVER_memory_init ()
1533 mallopt (M_TRIM_THRESHOLD, 4 * 1024);
1534 mallopt (M_TOP_PAD, 1 * 1024);
1540 /* end of gnunet-service-resolver.c */