GNUnet  0.11.x
Data Structures | Macros | Functions | Variables
gnunet-service-resolver.c File Reference

code to do DNS resolution More...

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_statistics_service.h"
#include "resolver.h"
Include dependency graph for gnunet-service-resolver.c:

Go to the source code of this file.

Data Structures

struct  RecordListEntry
 Entry in list of cached DNS records for a hostname. More...
 
struct  ResolveCache
 A cached DNS lookup result. More...
 
struct  ActiveLookup
 Information about pending lookups. More...
 

Macros

#define DNS_TIMEOUT   GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30)
 How long do we wait for DNS answers? More...
 
#define MAX_CACHE   1024
 Maximum number of hostnames we cache results for. More...
 

Functions

static void free_cache_entry (struct ResolveCache *rc)
 Remove entry from cache. More...
 
static void free_hosts_entry (struct ResolveCache *rc)
 Remove entry from cache. More...
 
static void free_active_lookup (struct ActiveLookup *al)
 Release resources associated with al. More...
 
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 ", and if so, return a copy of the nameserver's IP. More...
 
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's search domain. More...
 
static int lookup_dns_servers (char ***server_addrs)
 Reads the list of nameservers from /etc/resolve.conf. More...
 
static char * make_reverse_hostname (const void *ip, int af)
 Compute name to use for DNS reverse lookups from ip. More...
 
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. More...
 
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. More...
 
static int remove_expired (struct ResolveCache *rc)
 Remove expired entries from rc. More...
 
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 record_type. More...
 
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). More...
 
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. More...
 
static void cache_answers (const char *name, struct GNUNET_DNSPARSER_Record *records, unsigned int num_records)
 
static void handle_resolve_result (void *cls, const struct GNUNET_TUN_DnsHeader *dns, size_t dns_len)
 We got a result from DNS. More...
 
static void handle_resolve_timeout (void *cls)
 We encountered a timeout trying to perform a DNS lookup. More...
 
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. More...
 
static int check_get (void *cls, const struct GNUNET_RESOLVER_GetMessage *get)
 Verify well-formedness of GET-message. More...
 
static void handle_get (void *cls, const struct GNUNET_RESOLVER_GetMessage *msg)
 Handle GET-message. More...
 
static void shutdown_task (void *cls)
 Service is shutting down, clean up. More...
 
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. More...
 
static void extract_hosts (const char *line, size_t line_len)
 Extract host information from a line in /etc/hosts. More...
 
static void load_etc_hosts (void)
 Reads the list of hosts from /etc/hosts. More...
 
static void init_cb (void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg, struct GNUNET_SERVICE_Handle *sh)
 Service is starting, initialize everything. More...
 
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. More...
 
static void disconnect_cb (void *cls, struct GNUNET_SERVICE_Client *c, void *internal_cls)
 Callback called when a client disconnected from the service. More...
 
 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. More...
 

Variables

static struct ResolveCachecache_head
 Start of the linked list of cached DNS lookup results. More...
 
static struct ResolveCachecache_tail
 Tail of the linked list of cached DNS lookup results. More...
 
static struct ResolveCachehosts_head
 Head of the linked list of DNS lookup results from /etc/hosts. More...
 
static struct ResolveCachehosts_tail
 Tail of the linked list of DNS lookup results from /etc/hosts. More...
 
static struct ActiveLookuplookup_head
 Start of the linked list of active DNS lookups. More...
 
static struct ActiveLookuplookup_tail
 Tail of the linked list of active DNS lookups. More...
 
static struct GNUNET_DNSSTUB_Contextdnsstub_ctx
 context of dnsstub library More...
 
static char * my_domain
 My domain, to be appended to the hostname to get a FQDN. More...
 
static unsigned int cache_size
 How many entries do we have in cache_head DLL? More...
 

Detailed Description

code to do DNS resolution

Author
Christian Grothoff

Definition in file gnunet-service-resolver.c.

Macro Definition Documentation

◆ DNS_TIMEOUT

How long do we wait for DNS answers?

Definition at line 36 of file gnunet-service-resolver.c.

Referenced by resolve_and_cache().

◆ MAX_CACHE

#define MAX_CACHE   1024

Maximum number of hostnames we cache results for.

Definition at line 41 of file gnunet-service-resolver.c.

Referenced by handle_resolve_result().

Function Documentation

◆ free_cache_entry()

static void free_cache_entry ( struct ResolveCache rc)
static

Remove entry from cache.

Parameters
rcentry to free

Definition at line 209 of file gnunet-service-resolver.c.

References cache_size, GNUNET_CONTAINER_DLL_remove, GNUNET_DNSPARSER_free_record(), GNUNET_free, GNUNET_free_non_null, ResolveCache::hostname, RecordListEntry::record, ResolveCache::records_head, and ResolveCache::records_tail.

Referenced by handle_resolve_result(), remove_expired(), and shutdown_task().

210 {
211  struct RecordListEntry *pos;
212 
213  while (NULL != (pos = rc->records_head))
214  {
217  GNUNET_free (pos->record);
218  GNUNET_free (pos);
219  }
222  cache_size--;
223  GNUNET_free (rc);
224 }
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
static unsigned int cache_size
How many entries do we have in cache_head DLL?
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
void GNUNET_DNSPARSER_free_record(struct GNUNET_DNSPARSER_Record *r)
Free the given DNS record.
Definition: dnsparser.c:169
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
struct RecordListEntry * records_tail
tail of a double linked list containing the lookup results
struct GNUNET_DNSPARSER_Record * record
Cached data.
static struct ResolveCache * cache_tail
Tail of the linked list of cached DNS lookup results.
static struct ResolveCache * cache_head
Start of the linked list of cached DNS lookup results.
char * hostname
Which hostname is this cache for?
Entry in list of cached DNS records for a hostname.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ free_hosts_entry()

static void free_hosts_entry ( struct ResolveCache rc)
static

Remove entry from cache.

Parameters
rcentry to free

Definition at line 233 of file gnunet-service-resolver.c.

References cache_size, GNUNET_CONTAINER_DLL_remove, GNUNET_DNSPARSER_free_record(), GNUNET_free, GNUNET_free_non_null, ResolveCache::hostname, RecordListEntry::record, ResolveCache::records_head, and ResolveCache::records_tail.

Referenced by shutdown_task().

234 {
235  struct RecordListEntry *pos;
236 
237  while (NULL != (pos = rc->records_head))
238  {
241  GNUNET_free (pos->record);
242  GNUNET_free (pos);
243  }
246  cache_size--;
247  GNUNET_free (rc);
248 }
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
static unsigned int cache_size
How many entries do we have in cache_head DLL?
static struct ResolveCache * hosts_tail
Tail of the linked list of DNS lookup results from /etc/hosts.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
void GNUNET_DNSPARSER_free_record(struct GNUNET_DNSPARSER_Record *r)
Free the given DNS record.
Definition: dnsparser.c:169
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
struct RecordListEntry * records_tail
tail of a double linked list containing the lookup results
struct GNUNET_DNSPARSER_Record * record
Cached data.
static struct ResolveCache * hosts_head
Head of the linked list of DNS lookup results from /etc/hosts.
char * hostname
Which hostname is this cache for?
Entry in list of cached DNS records for a hostname.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ free_active_lookup()

static void free_active_lookup ( struct ActiveLookup al)
static

Release resources associated with al.

Parameters
alan active lookup

Definition at line 257 of file gnunet-service-resolver.c.

References GNUNET_CONTAINER_DLL_remove, GNUNET_DNSSTUB_resolve_cancel(), GNUNET_free, GNUNET_free_non_null, GNUNET_SCHEDULER_cancel(), ActiveLookup::hostname, ActiveLookup::resolve_handle, and ActiveLookup::timeout_task.

Referenced by disconnect_cb(), handle_resolve_result(), handle_resolve_timeout(), and shutdown_task().

258 {
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 }
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
struct GNUNET_SCHEDULER_Task * timeout_task
handle for the resolution timeout task
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
static struct ActiveLookup * lookup_tail
Tail of the linked list of active DNS lookups.
static struct ActiveLookup * lookup_head
Start of the linked list of active DNS lookups.
void GNUNET_DNSSTUB_resolve_cancel(struct GNUNET_DNSSTUB_RequestSocket *rs)
Cancel DNS resolution.
Definition: dnsstub.c:540
struct GNUNET_DNSSTUB_RequestSocket * resolve_handle
handle for cancelling a request
char * hostname
Which hostname are we resolving?
#define GNUNET_free(ptr)
Wrapper around free.
void * GNUNET_SCHEDULER_cancel(struct GNUNET_SCHEDULER_Task *task)
Cancel the task with the specified identifier.
Definition: scheduler.c:966
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◆ extract_dns_server()

static char* extract_dns_server ( const char *  line,
size_t  line_len 
)
static

Find out if the configuration file line contains a string starting with "nameserver ", and if so, return a copy of the nameserver's IP.

Parameters
lineline to parse
line_lennumber of characters in line
Returns
NULL if no nameserver is configured in this line

Definition at line 285 of file gnunet-service-resolver.c.

References GNUNET_strndup.

Referenced by lookup_dns_servers().

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 }
static char * line
Desired phone line (string to be converted to a hash).
#define GNUNET_strndup(a, length)
Wrapper around GNUNET_xstrndup_.
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◆ extract_search_domain()

static char* extract_search_domain ( const char *  line,
size_t  line_len 
)
static

Find out if the configuration file line contains a string starting with "search ", and if so, return a copy of the machine's search domain.

Parameters
lineline to parse
line_lennumber of characters in line
Returns
NULL if no nameserver is configured in this line

Definition at line 304 of file gnunet-service-resolver.c.

References GNUNET_strndup.

Referenced by lookup_dns_servers().

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 }
static char * line
Desired phone line (string to be converted to a hash).
#define GNUNET_strndup(a, length)
Wrapper around GNUNET_xstrndup_.
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◆ lookup_dns_servers()

static int lookup_dns_servers ( char ***  server_addrs)
static

Reads the list of nameservers from /etc/resolve.conf.

Parameters
server_addrs[out]a list of null-terminated server address strings
Returns
the number of server addresses in , -1 on error

Definition at line 320 of file gnunet-service-resolver.c.

References buf, extract_dns_server(), extract_search_domain(), fh, GNUNET_array_append, GNUNET_DISK_file_close(), GNUNET_DISK_file_handle_size(), GNUNET_DISK_file_map(), GNUNET_DISK_file_open(), GNUNET_DISK_file_unmap(), GNUNET_DISK_MAP_TYPE_READ, GNUNET_DISK_OPEN_READ, GNUNET_DISK_PERM_NONE, GNUNET_ERROR_TYPE_ERROR, GNUNET_log, GNUNET_OK, mh, my_domain, and SIZE_MAX.

Referenced by init_cb().

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 }
Open the file for reading.
int GNUNET_DISK_file_close(struct GNUNET_DISK_FileHandle *h)
Close an open file.
Definition: disk.c:1345
static struct GNUNET_CADET_Handle * mh
Cadet handle.
Definition: gnunet-cadet.c:92
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:1440
Nobody is allowed to do anything to the file.
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define SIZE_MAX
Definition: platform.h:216
Read-only memory map.
static char buf[2048]
static int fh
Handle to the unique file.
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.
int GNUNET_DISK_file_unmap(struct GNUNET_DISK_MapHandle *h)
Unmap a file.
Definition: disk.c:1477
#define GNUNET_array_append(arr, size, element)
Append an element to a list (growing the list by one).
int GNUNET_DISK_file_handle_size(struct GNUNET_DISK_FileHandle *fh, off_t *size)
Get the size of an open file.
Definition: disk.c:206
#define GNUNET_log(kind,...)
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:1268
Handle used to access files (and pipes).
Handle for a memory-mapping operation.
Definition: disk.c:1412
static char * my_domain
My domain, to be appended to the hostname to get a FQDN.
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◆ make_reverse_hostname()

static char* make_reverse_hostname ( const void *  ip,
int  af 
)
static

Compute name to use for DNS reverse lookups from ip.

Parameters
ipIP address to resolve, in binary format, network byte order
afaddress family of ip, AF_INET or AF_INET6

Definition at line 396 of file gnunet-service-resolver.c.

References buf, GNUNET_free, GNUNET_new_array, and GNUNET_snprintf().

Referenced by handle_get().

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 }
int GNUNET_snprintf(char *buf, size_t size, const char *format,...)
Like snprintf, just aborts if the buffer is of insufficient size.
static char buf[2048]
#define GNUNET_new_array(n, type)
Allocate a size n array with structs or unions of the given type.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ send_reply()

static int send_reply ( struct GNUNET_DNSPARSER_Record record,
uint16_t  record_type,
uint32_t  client_request_id,
struct GNUNET_SERVICE_Client client 
)
static

Send DNS record back to our client.

Parameters
recordinformation to transmit
record_typerequested record type from client
client_request_idto which request are we responding
clientwhere to send record
Returns
GNUNET_YES if we sent a reply, GNUNET_NO if the record type is not understood or does not match record_type

Definition at line 459 of file gnunet-service-resolver.c.

References GNUNET_RESOLVER_ResponseMessage::client_id, GNUNET_DNSPARSER_RawRecord::data, GNUNET_DNSPARSER_Record::data, GNUNET_DNSPARSER_RawRecord::data_len, env, GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_ALL, GNUNET_DNSPARSER_TYPE_CNAME, GNUNET_DNSPARSER_TYPE_PTR, GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_memcpy, GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE, GNUNET_MQ_msg_extra, GNUNET_MQ_send(), GNUNET_NO, GNUNET_SERVICE_client_get_mq(), GNUNET_YES, GNUNET_DNSPARSER_Record::hostname, msg, payload, GNUNET_DNSPARSER_Record::raw, and GNUNET_DNSPARSER_Record::type.

Referenced by try_cache().

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;
477 
479  if (GNUNET_DNSPARSER_TYPE_PTR != record_type)
480  return GNUNET_NO;
481  payload = record->data.hostname;
482  payload_len = strlen (record->data.hostname) + 1;
483  break;
484 
486  if ((GNUNET_DNSPARSER_TYPE_A != record_type) &&
487  (GNUNET_DNSPARSER_TYPE_ALL != record_type))
488  return GNUNET_NO;
489  payload = record->data.raw.data;
490  payload_len = record->data.raw.data_len;
491  break;
492 
494  if ((GNUNET_DNSPARSER_TYPE_AAAA != record_type) &&
495  (GNUNET_DNSPARSER_TYPE_ALL != record_type))
496  return GNUNET_NO;
497  payload = record->data.raw.data;
498  payload_len = record->data.raw.data_len;
499  break;
500 
501  default:
503  "Cannot handle DNS response type %u: not supported here\n",
504  record->type);
505  return GNUNET_NO;
506  }
507  env = GNUNET_MQ_msg_extra (msg,
508  payload_len,
510  msg->client_id = client_request_id;
511  GNUNET_memcpy (&msg[1], payload, payload_len);
513  return GNUNET_YES;
514 }
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
#define GNUNET_DNSPARSER_TYPE_CNAME
struct GNUNET_MQ_Handle * GNUNET_SERVICE_client_get_mq(struct GNUNET_SERVICE_Client *c)
Obtain the message queue of c.
Definition: service.c:2437
#define GNUNET_memcpy(dst, src, n)
Call memcpy() but check for n being 0 first.
#define GNUNET_NO
Definition: gnunet_common.h:78
uint32_t client_id
identifies the request this message responds to.
Definition: resolver.h:83
#define GNUNET_DNSPARSER_TYPE_PTR
#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
char * hostname
For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
union GNUNET_DNSPARSER_Record::@24 data
Payload of the record (which one of these is valid depends on the &#39;type&#39;).
#define GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE
Response to a DNS resolution request.
size_t data_len
Number of bytes in data.
void * data
Binary record data.
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
static unsigned long long payload
How much data are we currently storing in the database?
#define GNUNET_DNSPARSER_TYPE_AAAA
#define GNUNET_log(kind,...)
#define GNUNET_YES
Definition: gnunet_common.h:77
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
#define GNUNET_DNSPARSER_TYPE_ALL
struct GNUNET_DNSPARSER_RawRecord raw
Raw data for all other types.
#define GNUNET_DNSPARSER_TYPE_A
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◆ send_end_msg()

static void send_end_msg ( uint32_t  client_request_id,
struct GNUNET_SERVICE_Client client 
)
static

Send message to client that we transmitted all responses for client_request_id.

Parameters
client_request_idto which request are we responding
clientwhere to send record

Definition at line 525 of file gnunet-service-resolver.c.

References GNUNET_RESOLVER_ResponseMessage::client_id, env, GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE, GNUNET_MQ_msg, GNUNET_MQ_send(), GNUNET_SERVICE_client_get_mq(), and msg.

Referenced by handle_resolve_result(), handle_resolve_timeout(), process_get(), and try_cache().

526 {
528  struct GNUNET_MQ_Envelope *env;
529 
530  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending END message\n");
532  msg->client_id = client_request_id;
534 }
struct GNUNET_MessageHeader * msg
Definition: 005.c:2
struct GNUNET_MQ_Handle * GNUNET_SERVICE_client_get_mq(struct GNUNET_SERVICE_Client *c)
Obtain the message queue of c.
Definition: service.c:2437
#define GNUNET_MQ_msg(mvar, type)
Allocate a GNUNET_MQ_Envelope.
Definition: gnunet_mq_lib.h:67
uint32_t client_id
identifies the request this message responds to.
Definition: resolver.h:83
#define GNUNET_MESSAGE_TYPE_RESOLVER_RESPONSE
Response to a DNS resolution request.
struct GNUNET_MQ_Envelope * env
Definition: 005.c:1
#define GNUNET_log(kind,...)
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
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◆ remove_expired()

static int remove_expired ( struct ResolveCache rc)
static

Remove expired entries from rc.

Parameters
rcentry in resolver cache
Returns
GNUNET_YES if rc was completely expired GNUNET_NO if some entries are left

Definition at line 545 of file gnunet-service-resolver.c.

References GNUNET_TIME_Absolute::abs_value_us, free_cache_entry(), GNUNET_CONTAINER_DLL_remove, GNUNET_DNSPARSER_free_record(), GNUNET_free, GNUNET_NO, GNUNET_TIME_absolute_get(), GNUNET_YES, hostname, RecordListEntry::next, process_get(), ResolveCache::records_head, and ResolveCache::records_tail.

Referenced by try_cache().

546 {
548  struct RecordListEntry *n;
549 
550  for (struct RecordListEntry *pos = rc->records_head; NULL != pos; pos = n)
551  {
552  n = pos->next;
553  if (now.abs_value_us > pos->record->expiration_time.abs_value_us)
554  {
556  GNUNET_DNSPARSER_free_record (pos->record);
557  GNUNET_free (pos->record);
558  GNUNET_free (pos);
559  }
560  }
561  if (NULL == rc->records_head)
562  {
563  free_cache_entry (rc);
564  return GNUNET_YES;
565  }
566  return GNUNET_NO;
567 }
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
void GNUNET_DNSPARSER_free_record(struct GNUNET_DNSPARSER_Record *r)
Free the given DNS record.
Definition: dnsparser.c:169
#define GNUNET_NO
Definition: gnunet_common.h:78
struct RecordListEntry * next
This is a doubly linked list.
uint64_t abs_value_us
The actual value.
struct RecordListEntry * records_tail
tail of a double linked list containing the lookup results
struct GNUNET_TIME_Absolute GNUNET_TIME_absolute_get(void)
Get the current time.
Definition: time.c:118
static void free_cache_entry(struct ResolveCache *rc)
Remove entry from cache.
Time for absolute times used by GNUnet, in microseconds.
#define GNUNET_YES
Definition: gnunet_common.h:77
Entry in list of cached DNS records for a hostname.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ process_get()

static void process_get ( const char *  hostname,
uint16_t  record_type,
uint32_t  client_request_id,
struct GNUNET_SERVICE_Client client 
)
static

Process DNS request for hostname with request ID request_id from client demanding records of type record_type.

Process DNS request for hostname with request ID client_request_id from client demanding records of type record_type.

Parameters
hostnameDNS name to resolve
record_typedesired record type
client_request_idclient's request ID
clientwho should get the result?

Definition at line 946 of file gnunet-service-resolver.c.

References GNUNET_break, GNUNET_NO, GNUNET_OK, GNUNET_SERVICE_client_drop(), GNUNET_snprintf(), my_domain, resolve_and_cache(), send_end_msg(), and try_cache().

Referenced by handle_get(), remove_expired(), and try_cache().

950 {
951  char fqdn[255];
952 
953  if (GNUNET_NO != try_cache (hostname, record_type, client_request_id, client))
954  return;
955  if ((NULL != my_domain) && (NULL == strchr (hostname, (unsigned char) '.')) &&
956  (strlen (hostname) + strlen (my_domain) <= 253))
957  {
958  GNUNET_snprintf (fqdn, sizeof(fqdn), "%s.%s", hostname, my_domain);
959  }
960  else if (strlen (hostname) < 255)
961  {
962  GNUNET_snprintf (fqdn, sizeof(fqdn), "%s", hostname);
963  }
964  else
965  {
966  GNUNET_break (0);
968  return;
969  }
970  if (GNUNET_NO == try_cache (fqdn, record_type, client_request_id, client))
971  {
972  if (GNUNET_OK !=
973  resolve_and_cache (fqdn, record_type, client_request_id, client))
974  {
975  send_end_msg (client_request_id, client);
976  }
977  }
978 }
int GNUNET_snprintf(char *buf, size_t size, const char *format,...)
Like snprintf, just aborts if the buffer is of insufficient size.
#define GNUNET_NO
Definition: gnunet_common.h:78
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
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).
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.
void GNUNET_SERVICE_client_drop(struct GNUNET_SERVICE_Client *c)
Ask the server to disconnect from the given client.
Definition: service.c:2324
static char * hostname
Our hostname; we give this to all the peers we start.
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 char * my_domain
My domain, to be appended to the hostname to get a FQDN.
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◆ try_cache()

static int try_cache ( const char *  hostname,
uint16_t  record_type,
uint32_t  client_request_id,
struct GNUNET_SERVICE_Client client 
)
static

Get an IP address as a string (works for both IPv4 and IPv6).

Note that the resolution happens asynchronously and that the first call may not immediately result in the FQN (but instead in a human-readable IP address).

Parameters
hostnamewhat hostname was to be resolved
record_typewhat type of record was requested
client_request_idunique identification of the client's request
clienthandle to the client making the request (for sending the reply)

Definition at line 598 of file gnunet-service-resolver.c.

References cache_head, GNUNET_DNSPARSER_Record::data, GNUNET_CONTAINER_DLL_insert, GNUNET_CONTAINER_DLL_remove, GNUNET_DNSPARSER_TYPE_CNAME, GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_NO, GNUNET_YES, ResolveCache::hostname, GNUNET_DNSPARSER_Record::hostname, GNUNET_DNSPARSER_Record::name, RecordListEntry::next, ResolveCache::next, process_get(), RecordListEntry::record, ResolveCache::records_head, remove_expired(), send_end_msg(), send_reply(), and GNUNET_DNSPARSER_Record::type.

Referenced by handle_resolve_result(), and process_get().

602 {
603  struct ResolveCache *pos;
604  struct ResolveCache *next;
605  int found;
606  int in_hosts;
607 
608  in_hosts = GNUNET_NO;
609  for (pos = hosts_head; NULL != pos; pos = pos->next)
610  if (0 == strcmp (pos->hostname, hostname))
611  {
612  in_hosts = GNUNET_YES;
613  break;
614  }
615  if (NULL == pos)
616  {
617  next = cache_head;
618  for (pos = next; NULL != pos; pos = next)
619  {
620  next = pos->next;
621  if (GNUNET_YES == remove_expired (pos))
622  continue;
623  if (0 == strcmp (pos->hostname, hostname))
624  break;
625  }
626  }
627  if (NULL == pos)
628  {
629  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No cache entry for '%s'\n", hostname);
630  return GNUNET_NO;
631  }
632  if ((GNUNET_NO == in_hosts) && (cache_head != pos))
633  {
634  /* move result to head to achieve LRU for cache eviction */
637  }
638  found = GNUNET_NO;
639  for (struct RecordListEntry *rle = pos->records_head; NULL != rle;
640  rle = rle->next)
641  {
642  const struct GNUNET_DNSPARSER_Record *record = rle->record;
643 
645  "Checking cache entry for '%s', record is for '%s'\n",
646  hostname,
647  record->name);
648  if ((GNUNET_DNSPARSER_TYPE_CNAME == record->type) &&
649  (GNUNET_DNSPARSER_TYPE_CNAME != record_type) && (GNUNET_NO == found))
650  {
651  const char *hostname = record->data.hostname;
652 
653  process_get (hostname, record_type, client_request_id, client);
654  return GNUNET_YES; /* counts as a cache "hit" */
655  }
656  if (0 == strcmp (record->name, hostname))
657  found |= send_reply (rle->record, record_type, client_request_id, client);
658  }
659  if (GNUNET_NO == found)
660  return GNUNET_NO; /* had records, but none matched! */
661  send_end_msg (client_request_id, client);
662  return GNUNET_YES;
663 }
#define GNUNET_CONTAINER_DLL_remove(head, tail, element)
Remove an element from a DLL.
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
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.
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
#define GNUNET_DNSPARSER_TYPE_CNAME
#define GNUNET_NO
Definition: gnunet_common.h:78
struct ResolveCache * next
This is a doubly linked list.
struct RecordListEntry * next
This is a doubly linked list.
A cached DNS lookup result.
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.
static struct ResolveCache * hosts_head
Head of the linked list of DNS lookup results from /etc/hosts.
static int remove_expired(struct ResolveCache *rc)
Remove expired entries from rc.
union GNUNET_DNSPARSER_Record::@24 data
Payload of the record (which one of these is valid depends on the &#39;type&#39;).
static struct ResolveCache * cache_tail
Tail of the linked list of cached DNS lookup results.
A DNS response record.
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 struct ResolveCache * cache_head
Start of the linked list of cached DNS lookup results.
static char * hostname
Our hostname; we give this to all the peers we start.
#define GNUNET_log(kind,...)
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 void record(void *cls, size_t data_size, const void *data)
Process recorded audio data.
char * hostname
Which hostname is this cache for?
#define GNUNET_YES
Definition: gnunet_common.h:77
Entry in list of cached DNS records for a hostname.
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◆ pack()

static int pack ( const char *  hostname,
uint16_t  type,
uint16_t  dns_id,
char **  packet_buf,
size_t *  packet_size 
)
static

Create DNS query for hostname of type type with DNS request ID dns_id.

Parameters
hostnameDNS name to query
typerequested DNS record type
dns_idwhat should be the DNS request ID
packet_buf[out]where to write the request packet
packet_size[out]set to size of packet_buf on success
Returns
GNUNET_OK on success

Definition at line 678 of file gnunet-service-resolver.c.

References GNUNET_DNSPARSER_Query::dns_traffic_class, GNUNET_DNSPARSER_Packet::flags, GNUNET_DNSPARSER_pack(), GNUNET_ERROR_TYPE_ERROR, GNUNET_log, GNUNET_OK, GNUNET_SYSERR, GNUNET_TUN_DNS_CLASS_INTERNET, GNUNET_DNSPARSER_Packet::id, GNUNET_DNSPARSER_Query::name, GNUNET_DNSPARSER_Packet::num_queries, GNUNET_DNSPARSER_Packet::queries, GNUNET_TUN_DnsFlags::recursion_desired, GNUNET_DNSPARSER_Query::type, and type.

Referenced by handle_resolve_result(), and resolve_and_cache().

683 {
684  struct GNUNET_DNSPARSER_Query query;
685  struct GNUNET_DNSPARSER_Packet packet;
686 
687  query.name = (char *) hostname;
688  query.type = type;
689  query.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
690  memset (&packet, 0, sizeof(packet));
691  packet.num_queries = 1;
692  packet.queries = &query;
693  packet.id = htons (dns_id);
694  packet.flags.recursion_desired = 1;
695  if (GNUNET_OK !=
696  GNUNET_DNSPARSER_pack (&packet, UINT16_MAX, packet_buf, packet_size))
697  {
699  "Failed to pack query for hostname `%s'\n",
700  hostname);
701  packet_buf = NULL;
702  return GNUNET_SYSERR;
703  }
704  return GNUNET_OK;
705 }
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:1257
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define GNUNET_SYSERR
Definition: gnunet_common.h:76
#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 char * hostname
Our hostname; we give this to all the peers we start.
Easy-to-process, parsed version of a DNS packet.
#define GNUNET_log(kind,...)
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model
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◆ cache_answers()

static void cache_answers ( const char *  name,
struct GNUNET_DNSPARSER_Record records,
unsigned int  num_records 
)
static

Definition at line 709 of file gnunet-service-resolver.c.

References cache_size, GNUNET_CONTAINER_DLL_insert, GNUNET_DNSPARSER_duplicate_record(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_new, GNUNET_strdup, ResolveCache::hostname, GNUNET_DNSPARSER_Record::name, ResolveCache::next, RecordListEntry::record, ResolveCache::records_head, and ResolveCache::records_tail.

Referenced by handle_resolve_result().

712 {
713  struct ResolveCache *rc;
715  struct RecordListEntry *rle;
716 
717  for (unsigned int i = 0; i != num_records; i++)
718  {
719  record = &records[i];
720 
721  for (rc = cache_head; NULL != rc; rc = rc->next)
722  if (0 == strcasecmp (rc->hostname, name))
723  break;
724  if (NULL == rc)
725  {
726  rc = GNUNET_new (struct ResolveCache);
727  rc->hostname = GNUNET_strdup (name);
729  "Caching record for name %s under %s\n",
730  record->name, name);
732  cache_size++;
733  }
734  /* TODO: ought to check first if we have this exact record
735  already in the cache! */
736  rle = GNUNET_new (struct RecordListEntry);
739  }
740 }
static unsigned int cache_size
How many entries do we have in cache_head DLL?
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
#define GNUNET_new(type)
Allocate a struct or union of the given type.
struct ResolveCache * next
This is a doubly linked list.
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
A cached DNS lookup result.
struct RecordListEntry * records_tail
tail of a double linked list containing the lookup results
struct GNUNET_DNSPARSER_Record * record
Cached data.
char * name
Name of the record that the query is for (0-terminated).
static struct ResolveCache * cache_tail
Tail of the linked list of cached DNS lookup results.
A DNS response record.
struct GNUNET_DNSPARSER_Record * GNUNET_DNSPARSER_duplicate_record(const struct GNUNET_DNSPARSER_Record *r)
Duplicate (deep-copy) the given DNS record.
Definition: dnsparser.c:737
static struct ResolveCache * cache_head
Start of the linked list of cached DNS lookup results.
const char * name
#define GNUNET_log(kind,...)
static void record(void *cls, size_t data_size, const void *data)
Process recorded audio data.
char * hostname
Which hostname is this cache for?
Entry in list of cached DNS records for a hostname.
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◆ handle_resolve_result()

static void handle_resolve_result ( void *  cls,
const struct GNUNET_TUN_DnsHeader dns,
size_t  dns_len 
)
static

We got a result from DNS.

Add it to the cache and see if we can make our client happy...

Parameters
clsthe struct ActiveLookup
dnsthe DNS response
dns_lennumber of bytes in dns

Definition at line 752 of file gnunet-service-resolver.c.

References GNUNET_DNSPARSER_Packet::additional_records, GNUNET_DNSPARSER_Packet::answers, GNUNET_DNSPARSER_Packet::authority_records, cache_answers(), cache_size, ActiveLookup::client, ActiveLookup::client_request_id, ActiveLookup::did_aaaa, ActiveLookup::dns_id, free_active_lookup(), free_cache_entry(), GNUNET_CRYPTO_QUALITY_NONCE, GNUNET_CRYPTO_random_u32(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_parse(), GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_ALL, GNUNET_DNSSTUB_resolve(), GNUNET_DNSSTUB_resolve_cancel(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_ERROR, GNUNET_free, GNUNET_log, GNUNET_NO, GNUNET_OK, GNUNET_YES, ActiveLookup::hostname, GNUNET_DNSPARSER_Packet::id, MAX_CACHE, GNUNET_DNSPARSER_Packet::num_additional_records, GNUNET_DNSPARSER_Packet::num_answers, GNUNET_DNSPARSER_Packet::num_authority_records, pack(), ActiveLookup::record_type, ActiveLookup::resolve_handle, send_end_msg(), and try_cache().

Referenced by resolve_and_cache().

755 {
756  struct ActiveLookup *al = cls;
757  struct GNUNET_DNSPARSER_Packet *parsed;
758 
759  parsed = GNUNET_DNSPARSER_parse ((const char *) dns, dns_len);
760  if (NULL == parsed)
761  {
763  "Failed to parse DNS reply (hostname %s, request ID %u)\n",
764  al->hostname,
765  al->dns_id);
766  return;
767  }
768  if (al->dns_id != ntohs (parsed->id))
769  {
771  "Request ID in DNS reply does not match\n");
773  return;
774  }
775  if (0 == parsed->num_answers + parsed->num_authority_records
776  + parsed->num_additional_records)
777  {
779  "DNS reply (hostname %s, request ID %u) contains no answers\n",
780  al->hostname,
781  (unsigned int) al->client_request_id);
782  /* resume by trying again from cache */
783  if (GNUNET_NO == try_cache (al->hostname,
784  al->record_type,
785  al->client_request_id,
786  al->client))
787  /* cache failed, tell client we could not get an answer */
788  {
790  }
792  free_active_lookup (al);
793  return;
794  }
795  /* LRU-based cache eviction: we remove from tail */
796  while (cache_size > MAX_CACHE)
798 
800  "Got reply for hostname %s and request ID %u\n",
801  al->hostname,
802  (unsigned int) al->client_request_id);
803  /* add to cache */
804  cache_answers (al->hostname, parsed->answers, parsed->num_answers);
805  cache_answers (al->hostname,
806  parsed->authority_records,
807  parsed->num_authority_records);
808  cache_answers (al->hostname,
809  parsed->additional_records,
810  parsed->num_additional_records);
811 
812  /* see if we need to do the 2nd request for AAAA records */
813  if ((GNUNET_DNSPARSER_TYPE_ALL == al->record_type) &&
814  (GNUNET_NO == al->did_aaaa))
815  {
816  char *packet_buf;
817  size_t packet_size;
818  uint16_t dns_id;
819 
821  UINT16_MAX);
822  if (GNUNET_OK == pack (al->hostname,
824  dns_id,
825  &packet_buf,
826  &packet_size))
827  {
828  al->did_aaaa = GNUNET_YES;
829  al->dns_id = dns_id;
832  packet_buf,
833  packet_size,
835  al);
836  GNUNET_free (packet_buf);
838  return;
839  }
840  }
841 
842  /* resume by trying again from cache */
843  if (GNUNET_NO == try_cache (al->hostname,
844  al->record_type,
845  al->client_request_id,
846  al->client))
847  /* cache failed, tell client we could not get an answer */
848  {
850  }
851  free_active_lookup (al);
853 }
struct GNUNET_DNSPARSER_Record * answers
Array of all answers in the packet, must contain "num_answers" entries.
static unsigned int cache_size
How many entries do we have in cache_head DLL?
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 GNUNET_SERVICE_Client * client
The client that queried the records contained in this cache entry.
uint32_t GNUNET_CRYPTO_random_u32(enum GNUNET_CRYPTO_Quality mode, uint32_t i)
Produce a random value.
static struct GNUNET_DNSSTUB_Context * dnsstub_ctx
context of dnsstub library
uint16_t id
DNS ID (to match replies to requests).
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:78
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
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...
unsigned int num_answers
Number of answers in the packet, should be 0 for queries.
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).
uint32_t client_request_id
Unique request ID of a client if a query for this hostname/record_type is currently pending...
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.
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:656
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 struct ResolveCache * cache_tail
Tail of the linked list of cached DNS lookup results.
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 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:504
unsigned int num_authority_records
Number of authoritative answers in the packet, should be 0 for queries.
static void free_cache_entry(struct ResolveCache *rc)
Remove entry from cache.
#define GNUNET_DNSPARSER_TYPE_AAAA
void GNUNET_DNSSTUB_resolve_cancel(struct GNUNET_DNSSTUB_RequestSocket *rs)
Cancel DNS resolution.
Definition: dnsstub.c:540
Easy-to-process, parsed version of a DNS packet.
struct GNUNET_DNSSTUB_RequestSocket * resolve_handle
handle for cancelling a request
#define GNUNET_log(kind,...)
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.
#define GNUNET_YES
Definition: gnunet_common.h:77
static void free_active_lookup(struct ActiveLookup *al)
Release resources associated with al.
#define GNUNET_DNSPARSER_TYPE_ALL
char * hostname
Which hostname are we resolving?
#define MAX_CACHE
Maximum number of hostnames we cache results for.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ handle_resolve_timeout()

static void handle_resolve_timeout ( void *  cls)
static

We encountered a timeout trying to perform a DNS lookup.

Parameters
clsa struct ActiveLookup

Definition at line 863 of file gnunet-service-resolver.c.

References ActiveLookup::client, ActiveLookup::client_request_id, free_active_lookup(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, send_end_msg(), and ActiveLookup::timeout_task.

Referenced by resolve_and_cache().

864 {
865  struct ActiveLookup *al = cls;
866 
867  al->timeout_task = NULL;
868  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "DNS lookup timeout!\n");
870  free_active_lookup (al);
871 }
struct GNUNET_SERVICE_Client * client
The client that queried the records contained in this cache entry.
struct GNUNET_SCHEDULER_Task * timeout_task
handle for the resolution timeout task
uint32_t client_request_id
Unique request ID of a client if a query for this hostname/record_type is currently pending...
Information about pending lookups.
#define GNUNET_log(kind,...)
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 void free_active_lookup(struct ActiveLookup *al)
Release resources associated with al.
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◆ resolve_and_cache()

static int resolve_and_cache ( const char *  hostname,
uint16_t  record_type,
uint32_t  client_request_id,
struct GNUNET_SERVICE_Client client 
)
static

Initiate an active lookup, then cache the result and try to then complete the resolution.

Parameters
hostnameDNS name to resolve
record_typerecord type to locate
client_request_idclient request ID
clienthandle to the client
Returns
GNUNET_OK if the DNS query is now pending

Definition at line 885 of file gnunet-service-resolver.c.

References ActiveLookup::client, ActiveLookup::client_request_id, ActiveLookup::dns_id, DNS_TIMEOUT, GNUNET_CONTAINER_DLL_insert, GNUNET_CRYPTO_QUALITY_NONCE, GNUNET_CRYPTO_random_u32(), GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_ALL, GNUNET_DNSSTUB_resolve(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_ERROR, GNUNET_free, GNUNET_log, GNUNET_new, GNUNET_OK, GNUNET_SCHEDULER_add_delayed(), GNUNET_strdup, GNUNET_SYSERR, handle_resolve_result(), handle_resolve_timeout(), ActiveLookup::hostname, pack(), ActiveLookup::record_type, ActiveLookup::resolve_handle, ActiveLookup::timeout_task, and type.

Referenced by process_get().

889 {
890  char *packet_buf;
891  size_t packet_size;
892  struct ActiveLookup *al;
893  uint16_t dns_id;
894  uint16_t type;
895 
896  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "resolve_and_cache `%s'\n", hostname);
898  UINT16_MAX);
899 
902  else
903  type = record_type;
904  if (GNUNET_OK != pack (hostname, type, dns_id, &packet_buf, &packet_size))
905  {
907  "Failed to pack query for hostname `%s'\n",
908  hostname);
909  return GNUNET_SYSERR;
910  }
911 
912  al = GNUNET_new (struct ActiveLookup);
914  al->record_type = record_type;
916  al->dns_id = dns_id;
917  al->client = client;
918  al->timeout_task =
921  packet_buf,
922  packet_size,
924  al);
925  GNUNET_free (packet_buf);
928  "Resolving %s, client_request_id = %u, dns_id = %u\n",
929  hostname,
930  (unsigned int) client_request_id,
931  (unsigned int) dns_id);
932  return GNUNET_OK;
933 }
#define GNUNET_CONTAINER_DLL_insert(head, tail, element)
Insert an element at the head of a DLL.
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 GNUNET_SERVICE_Client * client
The client that queried the records contained in this cache entry.
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.
static struct GNUNET_DNSSTUB_Context * dnsstub_ctx
context of dnsstub library
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define GNUNET_new(type)
Allocate a struct or union of the given type.
static void handle_resolve_result(void *cls, const struct GNUNET_TUN_DnsHeader *dns, size_t dns_len)
We got a result from DNS.
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
#define DNS_TIMEOUT
How long do we wait for DNS answers?
uint16_t dns_id
Unique DNS request ID of a client if a query for this hostname/record_type is currently pending...
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:1253
uint32_t client_request_id
Unique request ID of a client if a query for this hostname/record_type is currently pending...
static struct ActiveLookup * lookup_tail
Tail of the linked list of active DNS lookups.
uint16_t record_type
type of queried DNS record
Randomness for IVs etc.
static void handle_resolve_timeout(void *cls)
We encountered a timeout trying to perform a DNS lookup.
Information about pending lookups.
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:504
#define GNUNET_SYSERR
Definition: gnunet_common.h:76
static struct ActiveLookup * lookup_head
Start of the linked list of active DNS lookups.
static char * hostname
Our hostname; we give this to all the peers we start.
struct GNUNET_DNSSTUB_RequestSocket * resolve_handle
handle for cancelling a request
#define GNUNET_log(kind,...)
enum GNUNET_TESTBED_UnderlayLinkModelType type
the type of this model
#define GNUNET_DNSPARSER_TYPE_ALL
#define GNUNET_DNSPARSER_TYPE_A
char * hostname
Which hostname are we resolving?
#define GNUNET_free(ptr)
Wrapper around free.
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◆ check_get()

static int check_get ( void *  cls,
const struct GNUNET_RESOLVER_GetMessage get 
)
static

Verify well-formedness of GET-message.

Parameters
clsclosure, unused
getthe actual message
Returns
GNUNET_OK if get is well-formed

Definition at line 989 of file gnunet-service-resolver.c.

References direction, GNUNET_break, GNUNET_MQ_check_zero_termination, GNUNET_NO, GNUNET_OK, GNUNET_SYSERR, and size.

990 {
991  uint16_t size;
992  int direction;
993  int af;
994 
995  (void) cls;
996  size = ntohs (get->header.size) - sizeof(*get);
997  direction = ntohl (get->direction);
998  if (GNUNET_NO == direction)
999  {
1001  return GNUNET_OK;
1002  }
1003  af = ntohl (get->af);
1004  switch (af)
1005  {
1006  case AF_INET:
1007  if (size != sizeof(struct in_addr))
1008  {
1009  GNUNET_break (0);
1010  return GNUNET_SYSERR;
1011  }
1012  break;
1013 
1014  case AF_INET6:
1015  if (size != sizeof(struct in6_addr))
1016  {
1017  GNUNET_break (0);
1018  return GNUNET_SYSERR;
1019  }
1020  break;
1021 
1022  default:
1023  GNUNET_break (0);
1024  return GNUNET_SYSERR;
1025  }
1026  return GNUNET_OK;
1027 }
int32_t direction
GNUNET_YES to get hostname from IP, GNUNET_NO to get IP from hostname.
Definition: resolver.h:54
#define GNUNET_NO
Definition: gnunet_common.h:78
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
uint16_t size
The length of the struct (in bytes, including the length field itself), in big-endian format...
#define GNUNET_break(cond)
Use this for internal assertion violations that are not fatal (can be handled) but should not occur...
enum GNUNET_ABD_AlgoDirectionFlags direction
API enum, filled and passed for collect/verify.
Definition: gnunet-abd.c:172
struct GNUNET_MessageHeader header
Type: GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST.
Definition: resolver.h:48
#define GNUNET_MQ_check_zero_termination(m)
Insert code for a "check_" function that verifies that a given variable-length message received over ...
#define GNUNET_SYSERR
Definition: gnunet_common.h:76
static unsigned int size
Size of the "table".
Definition: peer.c:67
int32_t af
Address family to use (AF_INET, AF_INET6 or AF_UNSPEC).
Definition: resolver.h:59

◆ handle_get()

static void handle_get ( void *  cls,
const struct GNUNET_RESOLVER_GetMessage msg 
)
static

Handle GET-message.

Parameters
clsidentification of the client
msgthe actual message

Definition at line 1037 of file gnunet-service-resolver.c.

References GNUNET_RESOLVER_GetMessage::af, GNUNET_RESOLVER_GetMessage::client_id, GNUNET_RESOLVER_GetMessage::direction, direction, GNUNET_assert, GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_ALL, GNUNET_DNSPARSER_TYPE_PTR, GNUNET_ERROR_TYPE_DEBUG, GNUNET_free_non_null, GNUNET_log, GNUNET_NO, GNUNET_SERVICE_client_continue(), GNUNET_strdup, hostname, make_reverse_hostname(), and process_get().

1038 {
1039  struct GNUNET_SERVICE_Client *client = cls;
1040  int direction;
1041  int af;
1042  uint32_t client_request_id;
1043  char *hostname;
1044 
1045  direction = ntohl (msg->direction);
1046  af = ntohl (msg->af);
1047  client_request_id = msg->client_id;
1049  if (GNUNET_NO == direction)
1050  {
1051  /* IP from hostname */
1052  hostname = GNUNET_strdup ((const char *) &msg[1]);
1054  "Client asks to resolve `%s'\n",
1055  hostname);
1056  switch (af)
1057  {
1058  case AF_UNSPEC: {
1059  process_get (hostname,
1061  client_request_id,
1062  client);
1063  break;
1064  }
1065 
1066  case AF_INET: {
1067  process_get (hostname,
1069  client_request_id,
1070  client);
1071  break;
1072  }
1073 
1074  case AF_INET6: {
1075  process_get (hostname,
1077  client_request_id,
1078  client);
1079  break;
1080  }
1081 
1082  default: {
1083  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "got invalid af: %d\n", af);
1084  GNUNET_assert (0);
1085  }
1086  }
1087  }
1088  else
1089  {
1090  /* hostname from IP */
1091  hostname = make_reverse_hostname (&msg[1], af);
1092  process_get (hostname,
1094  client_request_id,
1095  client);
1096  }
1097  GNUNET_free_non_null (hostname);
1098 }
static char * make_reverse_hostname(const void *ip, int af)
Compute name to use for DNS reverse lookups from ip.
int32_t direction
GNUNET_YES to get hostname from IP, GNUNET_NO to get IP from hostname.
Definition: resolver.h:54
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
#define GNUNET_NO
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_strdup(a)
Wrapper around GNUNET_xstrdup_.
enum GNUNET_ABD_AlgoDirectionFlags direction
API enum, filled and passed for collect/verify.
Definition: gnunet-abd.c:172
#define GNUNET_DNSPARSER_TYPE_PTR
Handle to a client that is connected to a service.
Definition: service.c:250
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...
int32_t af
Address family to use (AF_INET, AF_INET6 or AF_UNSPEC).
Definition: resolver.h:59
static char * hostname
Our hostname; we give this to all the peers we start.
#define GNUNET_DNSPARSER_TYPE_AAAA
uint32_t client_id
identifies the request and is contained in the response message.
Definition: resolver.h:65
#define GNUNET_log(kind,...)
#define GNUNET_DNSPARSER_TYPE_ALL
#define GNUNET_DNSPARSER_TYPE_A
void GNUNET_SERVICE_client_continue(struct GNUNET_SERVICE_Client *c)
Continue receiving further messages from the given client.
Definition: service.c:2243
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◆ shutdown_task()

static void shutdown_task ( void *  cls)
static

Service is shutting down, clean up.

Parameters
clsNULL, unused

Definition at line 1107 of file gnunet-service-resolver.c.

References free_active_lookup(), free_cache_entry(), free_hosts_entry(), GNUNET_DNSSTUB_stop(), GNUNET_free_non_null, and my_domain.

Referenced by init_cb().

1108 {
1109  (void) cls;
1110 
1111  while (NULL != lookup_head)
1113  while (NULL != cache_head)
1115  while (NULL != hosts_head)
1119 }
void GNUNET_DNSSTUB_stop(struct GNUNET_DNSSTUB_Context *ctx)
Cleanup DNSSTUB resolver.
Definition: dnsstub.c:690
static struct GNUNET_DNSSTUB_Context * dnsstub_ctx
context of dnsstub library
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
static struct ResolveCache * hosts_head
Head of the linked list of DNS lookup results from /etc/hosts.
static void free_hosts_entry(struct ResolveCache *rc)
Remove entry from cache.
static struct ResolveCache * cache_head
Start of the linked list of cached DNS lookup results.
static struct ActiveLookup * lookup_head
Start of the linked list of active DNS lookups.
static void free_cache_entry(struct ResolveCache *rc)
Remove entry from cache.
static void free_active_lookup(struct ActiveLookup *al)
Release resources associated with al.
static char * my_domain
My domain, to be appended to the hostname to get a FQDN.
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◆ add_host()

static void add_host ( const char *  hostname,
uint16_t  rec_type,
const void *  data,
size_t  data_size 
)
static

Add information about a host from /etc/hosts to our cache.

Parameters
hostnamethe name of the host
rec_typeDNS record type to use
datapayload
data_sizenumber of bytes in data

Definition at line 1132 of file gnunet-service-resolver.c.

References GNUNET_DNSPARSER_RawRecord::data, GNUNET_DNSPARSER_Record::data, GNUNET_DNSPARSER_RawRecord::data_len, data_size, GNUNET_DNSPARSER_Record::dns_traffic_class, GNUNET_DNSPARSER_Record::expiration_time, GNUNET_CONTAINER_DLL_insert, GNUNET_malloc, GNUNET_memdup, GNUNET_new, GNUNET_strdup, GNUNET_TIME_UNIT_FOREVER_ABS, GNUNET_TUN_DNS_CLASS_INTERNET, ResolveCache::hostname, GNUNET_DNSPARSER_Record::name, GNUNET_DNSPARSER_Record::raw, RecordListEntry::record, ResolveCache::records_head, ResolveCache::records_tail, and GNUNET_DNSPARSER_Record::type.

Referenced by extract_hosts(), and testbed_run().

1136 {
1137  struct ResolveCache *rc;
1138  struct RecordListEntry *rle;
1139  struct GNUNET_DNSPARSER_Record *rec;
1140 
1141  rec = GNUNET_malloc (sizeof(struct GNUNET_DNSPARSER_Record));
1143  rec->type = rec_type;
1145  rec->name = GNUNET_strdup (hostname);
1147  rec->data.raw.data_len = data_size;
1148  rle = GNUNET_new (struct RecordListEntry);
1149  rle->record = rec;
1150  rc = GNUNET_new (struct ResolveCache);
1154 }
uint16_t type
See GNUNET_DNSPARSER_TYPE_*.
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.
struct RecordListEntry * records_head
head of a double linked list containing the lookup results
static size_t data_size
Number of bytes in data.
Definition: gnunet-abd.c:187
#define GNUNET_memdup(buf, size)
Allocate and initialize a block of memory.
#define GNUNET_new(type)
Allocate a struct or union of the given type.
#define GNUNET_strdup(a)
Wrapper around GNUNET_xstrdup_.
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".
struct GNUNET_DNSPARSER_Record * record
Cached data.
char * name
Name of the record that the query is for (0-terminated).
static struct ResolveCache * hosts_head
Head of the linked list of DNS lookup results from /etc/hosts.
union GNUNET_DNSPARSER_Record::@24 data
Payload of the record (which one of these is valid depends on the &#39;type&#39;).
A DNS response record.
size_t data_len
Number of bytes in data.
void * data
Binary record data.
#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...
struct GNUNET_TIME_Absolute expiration_time
When does the record expire?
static char * hostname
Our hostname; we give this to all the peers we start.
uint16_t dns_traffic_class
See GNUNET_TUN_DNS_CLASS_*.
char * hostname
Which hostname is this cache for?
uint32_t data
The data value.
Entry in list of cached DNS records for a hostname.
struct GNUNET_DNSPARSER_RawRecord raw
Raw data for all other types.
#define GNUNET_malloc(size)
Wrapper around malloc.
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◆ extract_hosts()

static void extract_hosts ( const char *  line,
size_t  line_len 
)
static

Extract host information from a line in /etc/hosts.

Parameters
linethe line to parse
line_lennumber of bytes in line

Definition at line 1164 of file gnunet-service-resolver.c.

References add_host(), GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_free, GNUNET_strndup, line, and memrchr.

Referenced by load_etc_hosts().

1165 {
1166  const char *c;
1167  struct in_addr v4;
1168  struct in6_addr v6;
1169  char *tbuf;
1170  char *tok;
1171 
1172  /* ignore everything after '#' */
1173  c = memrchr (line, (unsigned char) '#', line_len);
1174  if (NULL != c)
1175  line_len = c - line;
1176  /* ignore leading whitespace */
1177  while ((0 < line_len) && isspace ((unsigned char) *line))
1178  {
1179  line++;
1180  line_len--;
1181  }
1182  tbuf = GNUNET_strndup (line, line_len);
1183  tok = strtok (tbuf, " \t");
1184  if (NULL == tok)
1185  {
1186  GNUNET_free (tbuf);
1187  return;
1188  }
1189  if (1 == inet_pton (AF_INET, tok, &v4))
1190  {
1191  while (NULL != (tok = strtok (NULL, " \t")))
1192  add_host (tok, GNUNET_DNSPARSER_TYPE_A, &v4, sizeof(struct in_addr));
1193  }
1194  else if (1 == inet_pton (AF_INET6, tok, &v6))
1195  {
1196  while (NULL != (tok = strtok (NULL, " \t")))
1197  add_host (tok, GNUNET_DNSPARSER_TYPE_AAAA, &v6, sizeof(struct in6_addr));
1198  }
1199  GNUNET_free (tbuf);
1200 }
#define memrchr(s, c, n)
Definition: compat.h:49
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.
static char * line
Desired phone line (string to be converted to a hash).
#define GNUNET_strndup(a, length)
Wrapper around GNUNET_xstrndup_.
#define GNUNET_DNSPARSER_TYPE_AAAA
#define GNUNET_DNSPARSER_TYPE_A
#define GNUNET_free(ptr)
Wrapper around free.
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◆ load_etc_hosts()

static void load_etc_hosts ( void  )
static

Reads the list of hosts from /etc/hosts.

Definition at line 1207 of file gnunet-service-resolver.c.

References buf, extract_hosts(), fh, GNUNET_DISK_file_close(), GNUNET_DISK_file_handle_size(), GNUNET_DISK_file_map(), GNUNET_DISK_file_open(), GNUNET_DISK_file_unmap(), GNUNET_DISK_MAP_TYPE_READ, GNUNET_DISK_OPEN_READ, GNUNET_DISK_PERM_NONE, GNUNET_ERROR_TYPE_ERROR, GNUNET_ERROR_TYPE_INFO, GNUNET_log, GNUNET_OK, mh, and SIZE_MAX.

Referenced by init_cb().

1208 {
1209  struct GNUNET_DISK_FileHandle *fh;
1210  struct GNUNET_DISK_MapHandle *mh;
1211  off_t bytes_read;
1212  const char *buf;
1213  size_t read_offset;
1214 
1215  fh = GNUNET_DISK_file_open ("/etc/hosts",
1218  if (NULL == fh)
1219  {
1220  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Failed to open /etc/hosts");
1221  return;
1222  }
1223  if (GNUNET_OK != GNUNET_DISK_file_handle_size (fh, &bytes_read))
1224  {
1226  "Could not determin size of /etc/hosts. "
1227  "DNS resolution will not be possible.\n");
1229  return;
1230  }
1231  if (((unsigned long long) bytes_read) > (unsigned long long) SIZE_MAX)
1232  {
1234  "/etc/hosts file too large to mmap. "
1235  "DNS resolution will not be possible.\n");
1237  return;
1238  }
1239  buf = GNUNET_DISK_file_map (fh,
1240  &mh,
1242  (size_t) bytes_read);
1243  read_offset = 0;
1244  while (read_offset < (size_t) bytes_read)
1245  {
1246  const char *newline;
1247  size_t line_len;
1248 
1249  newline = strchr (buf + read_offset, '\n');
1250  if (NULL == newline)
1251  break;
1252  line_len = newline - buf - read_offset;
1253  extract_hosts (buf + read_offset, line_len);
1254  read_offset += line_len + 1;
1255  }
1258 }
Open the file for reading.
int GNUNET_DISK_file_close(struct GNUNET_DISK_FileHandle *h)
Close an open file.
Definition: disk.c:1345
static struct GNUNET_CADET_Handle * mh
Cadet handle.
Definition: gnunet-cadet.c:92
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:1440
Nobody is allowed to do anything to the file.
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define SIZE_MAX
Definition: platform.h:216
Read-only memory map.
static char buf[2048]
static int fh
Handle to the unique file.
int GNUNET_DISK_file_unmap(struct GNUNET_DISK_MapHandle *h)
Unmap a file.
Definition: disk.c:1477
int GNUNET_DISK_file_handle_size(struct GNUNET_DISK_FileHandle *fh, off_t *size)
Get the size of an open file.
Definition: disk.c:206
#define GNUNET_log(kind,...)
static void extract_hosts(const char *line, size_t line_len)
Extract host information from a line in /etc/hosts.
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:1268
Handle used to access files (and pipes).
Handle for a memory-mapping operation.
Definition: disk.c:1412
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◆ init_cb()

static void init_cb ( void *  cls,
const struct GNUNET_CONFIGURATION_Handle cfg,
struct GNUNET_SERVICE_Handle sh 
)
static

Service is starting, initialize everything.

Parameters
clsNULL, unused
cfgour configuration
shservice handle

Definition at line 1269 of file gnunet-service-resolver.c.

References _, GNUNET_DNSSTUB_add_dns_ip(), GNUNET_DNSSTUB_start(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_ERROR, GNUNET_free, GNUNET_free_non_null, GNUNET_log, GNUNET_OK, GNUNET_SCHEDULER_add_shutdown(), load_etc_hosts(), lookup_dns_servers(), result, and shutdown_task().

Referenced by disconnect_cb().

1272 {
1273  char **dns_servers;
1274  int num_dns_servers;
1275 
1276  (void) cfg;
1277  (void) sh;
1278  load_etc_hosts ();
1281  dns_servers = NULL;
1282  num_dns_servers = lookup_dns_servers (&dns_servers);
1283  if (0 >= num_dns_servers)
1284  {
1285  GNUNET_log (
1287  _ ("No DNS server available. DNS resolution will not be possible.\n"));
1288  return;
1289  }
1290  for (int i = 0; i < num_dns_servers; i++)
1291  {
1292  int result = GNUNET_DNSSTUB_add_dns_ip (dnsstub_ctx, dns_servers[i]);
1294  "Adding DNS server '%s': %s\n",
1295  dns_servers[i],
1296  GNUNET_OK == result ? "success" : "failure");
1297  GNUNET_free (dns_servers[i]);
1298  }
1299  GNUNET_free_non_null (dns_servers);
1300 }
static void load_etc_hosts(void)
Reads the list of hosts from /etc/hosts.
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:1300
static struct GNUNET_DNSSTUB_Context * dnsstub_ctx
context of dnsstub library
static void shutdown_task(void *cls)
Service is shutting down, clean up.
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:591
#define GNUNET_OK
Named constants for return values.
Definition: gnunet_common.h:75
#define GNUNET_free_non_null(ptr)
Free the memory pointed to by ptr if ptr is not NULL.
#define _(String)
GNU gettext support macro.
Definition: platform.h:181
struct GNUNET_DNSSTUB_Context * GNUNET_DNSSTUB_start(unsigned int num_sockets)
Start a DNS stub resolver.
Definition: dnsstub.c:564
static int result
Global testing status.
#define GNUNET_log(kind,...)
static int lookup_dns_servers(char ***server_addrs)
Reads the list of nameservers from /etc/resolve.conf.
#define GNUNET_free(ptr)
Wrapper around free.
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◆ connect_cb()

static void* connect_cb ( void *  cls,
struct GNUNET_SERVICE_Client c,
struct GNUNET_MQ_Handle mq 
)
static

Callback called when a client connects to the service.

Parameters
clsclosure for the service, unused
cthe new client that connected to the service
mqthe message queue used to send messages to the client
Returns
c

Definition at line 1312 of file gnunet-service-resolver.c.

Referenced by disconnect_cb().

1315 {
1316  (void) cls;
1317  (void) mq;
1318 
1319  return c;
1320 }
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◆ disconnect_cb()

static void disconnect_cb ( void *  cls,
struct GNUNET_SERVICE_Client c,
void *  internal_cls 
)
static

Callback called when a client disconnected from the service.

Parameters
clsclosure for the service
cthe client that disconnected
internal_clsshould be equal to c

Definition at line 1331 of file gnunet-service-resolver.c.

References __attribute__, connect_cb(), free_active_lookup(), GNUNET_assert, GNUNET_MESSAGE_TYPE_RESOLVER_REQUEST, GNUNET_MQ_handler_end, GNUNET_MQ_hd_var_size, GNUNET_SERVICE_MAIN(), GNUNET_SERVICE_OPTION_NONE, init_cb(), lookup_head, and ActiveLookup::next.

1332 {
1333  struct ActiveLookup *n;
1334 
1335  (void) cls;
1336 
1337  GNUNET_assert (c == internal_cls);
1338  n = lookup_head;
1339  for (struct ActiveLookup *al = n; NULL != al; al = n)
1340  {
1341  n = al->next;
1342  if (al->client == c)
1343  free_active_lookup (al);
1344  }
1345 }
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
Information about pending lookups.
static struct ActiveLookup * lookup_head
Start of the linked list of active DNS lookups.
struct ActiveLookup * next
Stored in a DLL.
static void free_active_lookup(struct ActiveLookup *al)
Release resources associated with al.
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◆ GNUNET_SERVICE_MAIN()

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.

Referenced by disconnect_cb().

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Variable Documentation

◆ cache_head

struct ResolveCache* cache_head
static

Start of the linked list of cached DNS lookup results.

Definition at line 160 of file gnunet-service-resolver.c.

Referenced by try_cache().

◆ cache_tail

struct ResolveCache* cache_tail
static

Tail of the linked list of cached DNS lookup results.

Definition at line 165 of file gnunet-service-resolver.c.

◆ hosts_head

struct ResolveCache* hosts_head
static

Head of the linked list of DNS lookup results from /etc/hosts.

Definition at line 170 of file gnunet-service-resolver.c.

◆ hosts_tail

struct ResolveCache* hosts_tail
static

Tail of the linked list of DNS lookup results from /etc/hosts.

Definition at line 175 of file gnunet-service-resolver.c.

◆ lookup_head

struct ActiveLookup* lookup_head
static

Start of the linked list of active DNS lookups.

Definition at line 180 of file gnunet-service-resolver.c.

Referenced by disconnect_cb().

◆ lookup_tail

struct ActiveLookup* lookup_tail
static

Tail of the linked list of active DNS lookups.

Definition at line 185 of file gnunet-service-resolver.c.

◆ dnsstub_ctx

struct GNUNET_DNSSTUB_Context* dnsstub_ctx
static

context of dnsstub library

Definition at line 190 of file gnunet-service-resolver.c.

◆ my_domain

char* my_domain
static

My domain, to be appended to the hostname to get a FQDN.

Definition at line 195 of file gnunet-service-resolver.c.

Referenced by lookup_dns_servers(), process_get(), and shutdown_task().

◆ cache_size

unsigned int cache_size
static

How many entries do we have in cache_head DLL?

Definition at line 200 of file gnunet-service-resolver.c.

Referenced by cache_answers(), free_cache_entry(), free_hosts_entry(), and handle_resolve_result().