plugin_block_dns.c File Reference

block plugin for advertising a DNS exit service More...

#include "platform.h"
#include "gnunet_block_plugin.h"
#include "block_dns.h"
#include "gnunet_signatures.h"
#include "gnunet_block_group_lib.h"

Include dependency graph for plugin_block_dns.c:

Go to the source code of this file.

Macros
#define	BLOOMFILTER_K   16
	Number of bits we set per entry in the bloomfilter. More...

Functions
static struct GNUNET_BLOCK_Group *	block_plugin_dns_create_group (void *cls, enum GNUNET_BLOCK_Type type, const void *raw_data, size_t raw_data_size, va_list va)
	Create a new block group. More...
static enum GNUNET_GenericReturnValue	block_plugin_dns_check_query (void *cls, enum GNUNET_BLOCK_Type type, const struct GNUNET_HashCode *query, const void *xquery, size_t xquery_size)
	Function called to validate a query. More...
static enum GNUNET_GenericReturnValue	block_plugin_dns_check_block (void *cls, enum GNUNET_BLOCK_Type type, const void *block, size_t block_size)
	Function called to validate a block for storage. More...
static enum GNUNET_BLOCK_ReplyEvaluationResult	block_plugin_dns_check_reply (void *cls, enum GNUNET_BLOCK_Type type, struct GNUNET_BLOCK_Group *group, const struct GNUNET_HashCode *query, const void *xquery, size_t xquery_size, const void *reply_block, size_t reply_block_size)
	Function called to validate a reply to a request. More...
static enum GNUNET_GenericReturnValue	block_plugin_dns_get_key (void *cls, enum GNUNET_BLOCK_Type type, const void *block, size_t block_size, struct GNUNET_HashCode *key)
	Function called to obtain the key for a block. More...
void *	libgnunet_plugin_block_dns_init (void *cls)
	Entry point for the plugin. More...
void *	libgnunet_plugin_block_dns_done (void *cls)
	Exit point from the plugin. More...

Detailed Description

block plugin for advertising a DNS exit service

Author

Christian Grothoff

Note that this plugin might more belong with EXIT and PT as those two are using this type of block. Still, this might be a natural enough place for people to find the code...

Definition in file plugin_block_dns.c.

Macro Definition Documentation

BLOOMFILTER_K

#define BLOOMFILTER_K   16

Number of bits we set per entry in the bloomfilter.

Do not change!

Definition at line 41 of file plugin_block_dns.c.

Function Documentation

block_plugin_dns_create_group()

static struct GNUNET_BLOCK_Group * block_plugin_dns_create_group ( void *  cls, enum GNUNET_BLOCK_Type  type, const void *  raw_data, size_t  raw_data_size, va_list  va  )

static

Create a new block group.

Parameters

ctx	block context in which the block group is created
type	type of the block for which we are creating the group
raw_data	optional serialized prior state of the group, NULL if unavailable/fresh
raw_data_size	number of bytes in raw_data, 0 if unavailable/fresh
va	variable arguments specific to type

Returns

block group handle, NULL if block groups are not supported by this type of block (this is not an error)

Definition at line 56 of file plugin_block_dns.c.

{
  unsigned int bf_size;
  const char *guard;
 
  guard = va_arg (va, const char *);
  if (0 == strcmp (guard,
                   "seen-set-size"))
    bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va, unsigned
                                                                   int),
                                                           BLOOMFILTER_K);
  else if (0 == strcmp (guard,
                        "filter-size"))
    bf_size = va_arg (va, unsigned int);
  else
  {
    GNUNET_break (0);
    bf_size = 8;
  }
  GNUNET_break (NULL == va_arg (va, const char *));
  return GNUNET_BLOCK_GROUP_bf_create (cls,
                                       bf_size,
                                       BLOOMFILTER_K,
                                       type,
                                       raw_data,
                                       raw_data_size);
}

References BLOOMFILTER_K, GNUNET_BLOCK_GROUP_bf_create(), GNUNET_BLOCK_GROUP_compute_bloomfilter_size(), GNUNET_break, and type.

Referenced by libgnunet_plugin_block_dns_init().

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block_plugin_dns_check_query()

static enum GNUNET_GenericReturnValue block_plugin_dns_check_query ( void *  cls, enum GNUNET_BLOCK_Type  type, const struct GNUNET_HashCode *  query, const void *  xquery, size_t  xquery_size  )

static

Function called to validate a query.

Parameters

cls	closure
type	block type
query	original query (hash)
xquery	extrended query data (can be NULL, depending on type)
xquery_size	number of bytes in xquery

Returns

GNUNET_OK if the query is fine, GNUNET_NO if not

Definition at line 100 of file plugin_block_dns.c.

{
  switch (type)
  {
  case GNUNET_BLOCK_TYPE_DNS:
    if (0 != xquery_size)
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    return GNUNET_OK;
  default:
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
}

References GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_break_op, GNUNET_NO, GNUNET_OK, GNUNET_SYSERR, and type.

Referenced by libgnunet_plugin_block_dns_init().

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block_plugin_dns_check_block()

static enum GNUNET_GenericReturnValue block_plugin_dns_check_block ( void *  cls, enum GNUNET_BLOCK_Type  type, const void *  block, size_t  block_size  )

static

Function called to validate a block for storage.

Parameters

cls	closure
type	block type
block	block data to validate
block_size	number of bytes in block

Returns

GNUNET_OK if the block is fine, GNUNET_NO if not

Definition at line 132 of file plugin_block_dns.c.

{
  const struct GNUNET_DNS_Advertisement *ad;
 
  switch (type)
  {
  case GNUNET_BLOCK_TYPE_DNS:
    if (sizeof(struct GNUNET_DNS_Advertisement) != block_size)
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    ad = block;
 
    if (ntohl (ad->purpose.size) !=
        sizeof(struct GNUNET_DNS_Advertisement)
        - sizeof(struct GNUNET_CRYPTO_EddsaSignature))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    if (GNUNET_TIME_absolute_is_past (
          GNUNET_TIME_absolute_ntoh (ad->expiration_time)))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "DNS advertisement has expired\n");
      return GNUNET_NO;
    }
    if (GNUNET_OK !=
        GNUNET_CRYPTO_eddsa_verify_ (GNUNET_SIGNATURE_PURPOSE_DNS_RECORD,
                                     &ad->purpose,
                                     &ad->signature,
                                     &ad->peer.public_key))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    return GNUNET_OK;
  default:
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
}

References GNUNET_DNS_Advertisement::expiration_time, GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_break_op, GNUNET_CRYPTO_eddsa_verify_(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_log, GNUNET_NO, GNUNET_OK, GNUNET_SIGNATURE_PURPOSE_DNS_RECORD, GNUNET_SYSERR, GNUNET_TIME_absolute_is_past(), GNUNET_TIME_absolute_ntoh(), GNUNET_DNS_Advertisement::peer, GNUNET_PeerIdentity::public_key, GNUNET_DNS_Advertisement::purpose, GNUNET_DNS_Advertisement::signature, GNUNET_CRYPTO_EccSignaturePurpose::size, and type.

Referenced by libgnunet_plugin_block_dns_init().

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block_plugin_dns_check_reply()

static enum GNUNET_BLOCK_ReplyEvaluationResult block_plugin_dns_check_reply ( void *  cls, enum GNUNET_BLOCK_Type  type, struct GNUNET_BLOCK_Group *  group, const struct GNUNET_HashCode *  query, const void *  xquery, size_t  xquery_size, const void *  reply_block, size_t  reply_block_size  )

static

Function called to validate a reply to a request.

Note that it is assumed that the reply has already been matched to the key (and signatures checked) as it would be done with the GetKeyFunction and the BlockEvaluationFunction.

Parameters

cls	closure
type	block type
group	which block group to use for evaluation
query	original query (hash)
xquery	extrended query data (can be NULL, depending on type)
xquery_size	number of bytes in xquery
reply_block	response to validate
reply_block_size	number of bytes in reply_block

Returns

characterization of result

Definition at line 197 of file plugin_block_dns.c.

{
  struct GNUNET_HashCode phash;
 
  switch (type)
  {
  case GNUNET_BLOCK_TYPE_DNS:
    GNUNET_CRYPTO_hash (reply_block,
                        reply_block_size,
                        &phash);
    if (GNUNET_YES ==
        GNUNET_BLOCK_GROUP_bf_test_and_set (group,
                                            &phash))
      return GNUNET_BLOCK_REPLY_OK_DUPLICATE;
    return GNUNET_BLOCK_REPLY_OK_MORE;
  default:
    GNUNET_break (0);
    return GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED;
  }
}

References GNUNET_BLOCK_GROUP_bf_test_and_set(), GNUNET_BLOCK_REPLY_OK_DUPLICATE, GNUNET_BLOCK_REPLY_OK_MORE, GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED, GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_CRYPTO_hash(), GNUNET_YES, and type.

Referenced by libgnunet_plugin_block_dns_init().

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block_plugin_dns_get_key()

static enum GNUNET_GenericReturnValue block_plugin_dns_get_key ( void *  cls, enum GNUNET_BLOCK_Type  type, const void *  block, size_t  block_size, struct GNUNET_HashCode *  key  )

static

Function called to obtain the key for a block.

Parameters

cls	closure
type	block type
block	block to get the key for
block_size	number of bytes in block
key	set to the key (query) for the given block

Returns

GNUNET_OK on success, GNUNET_SYSERR if type not supported (or if extracting a key from a block of this type does not work)

Definition at line 239 of file plugin_block_dns.c.

{
  if (GNUNET_BLOCK_TYPE_DNS != type)
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_NO;
}

References GNUNET_BLOCK_TYPE_DNS, GNUNET_break, GNUNET_NO, GNUNET_SYSERR, and type.

Referenced by libgnunet_plugin_block_dns_init().

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libgnunet_plugin_block_dns_init()

void * libgnunet_plugin_block_dns_init

(

void *

cls

)

Entry point for the plugin.

Definition at line 260 of file plugin_block_dns.c.

{
  static enum GNUNET_BLOCK_Type types[] = {
    GNUNET_BLOCK_TYPE_DNS,
    GNUNET_BLOCK_TYPE_ANY       /* end of list */
  };
  struct GNUNET_BLOCK_PluginFunctions *api;
 
  api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
  api->get_key = &block_plugin_dns_get_key;
  api->check_query = &block_plugin_dns_check_query;
  api->check_block = &block_plugin_dns_check_block;
  api->check_reply = &block_plugin_dns_check_reply;
  api->create_group = &block_plugin_dns_create_group;
  api->types = types;
  return api;
}

References block_plugin_dns_check_block(), block_plugin_dns_check_query(), block_plugin_dns_check_reply(), block_plugin_dns_create_group(), block_plugin_dns_get_key(), GNUNET_BLOCK_PluginFunctions::check_block, GNUNET_BLOCK_PluginFunctions::check_query, GNUNET_BLOCK_PluginFunctions::check_reply, GNUNET_BLOCK_PluginFunctions::create_group, GNUNET_BLOCK_PluginFunctions::get_key, GNUNET_BLOCK_TYPE_ANY, GNUNET_BLOCK_TYPE_DNS, GNUNET_new, and GNUNET_BLOCK_PluginFunctions::types.

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libgnunet_plugin_block_dns_done()

void * libgnunet_plugin_block_dns_done

(

void *

cls

)

Exit point from the plugin.

Definition at line 285 of file plugin_block_dns.c.

{
  struct GNUNET_BLOCK_PluginFunctions *api = cls;
 
  GNUNET_free (api);
  return NULL;
}

References GNUNET_BLOCK_PluginFunctions::cls, and GNUNET_free.