gnunet-service-rps_sampler_elem.h File Reference

sampler element implementation More...

#include <inttypes.h>

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Data Structures
struct	RPS_SamplerElement
	A sampler element sampling one PeerID at a time. More...

Enumerations
enum	RPS_SamplerEmpty { NOT_EMPTY = 0x0 , EMPTY = 0x1 }
	Used to indicate whether a sampler element is empty. More...

Functions
void	RPS_sampler_elem_reinit (struct RPS_SamplerElement *sampler_elem)
	Reinitialise a previously initialised sampler element.
struct RPS_SamplerElement *	RPS_sampler_elem_create (void)
	Create a sampler element and initialise it.
void	RPS_sampler_elem_destroy (struct RPS_SamplerElement *sampler_elem)
	Destroy a sampler element.
void	RPS_sampler_elem_next (struct RPS_SamplerElement *sampler_elem, const struct GNUNET_PeerIdentity *new_ID)
	Update a sampler element with a PeerID.
void	RPS_sampler_elem_set (struct RPS_SamplerElement *sampler_elem, struct GNUNET_CRYPTO_AuthKey auth_key)
	Set the min-wise independent function of the given sampler element.

Detailed Description

sampler element implementation

Author

Julius Bünger

Definition in file gnunet-service-rps_sampler_elem.h.

Enumeration Type Documentation

RPS_SamplerEmpty

enum RPS_SamplerEmpty

Used to indicate whether a sampler element is empty.

Enumerator
NOT_EMPTY
EMPTY

Definition at line 40 of file gnunet-service-rps_sampler_elem.h.

{
  NOT_EMPTY = 0x0,
  EMPTY = 0x1
};

Function Documentation

RPS_sampler_elem_reinit()

void RPS_sampler_elem_reinit

(

struct RPS_SamplerElement *

sampler_elem

)

Reinitialise a previously initialised sampler element.

Parameters

sampler_el	The sampler element to (re-) initialise
sampler_elem	The sampler element to (re-) initialise

Definition at line 50 of file gnunet-service-rps_sampler_elem.c.

{
  sampler_elem->is_empty = EMPTY;
 
  // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
  GNUNET_CRYPTO_random_block (&(sampler_elem->auth_key.key),
                              GNUNET_CRYPTO_HASH_LENGTH);
 
  sampler_elem->last_client_request = GNUNET_TIME_UNIT_FOREVER_ABS;
 
  sampler_elem->birth = GNUNET_TIME_absolute_get ();
  sampler_elem->num_peers = 0;
  sampler_elem->num_change = 0;
}

References RPS_SamplerElement::auth_key, RPS_SamplerElement::birth, EMPTY, GNUNET_CRYPTO_HASH_LENGTH, GNUNET_CRYPTO_random_block(), GNUNET_TIME_absolute_get(), GNUNET_TIME_UNIT_FOREVER_ABS, RPS_SamplerElement::is_empty, GNUNET_CRYPTO_AuthKey::key, RPS_SamplerElement::last_client_request, RPS_SamplerElement::num_change, and RPS_SamplerElement::num_peers.

Referenced by RPS_sampler_elem_create(), RPS_sampler_reinitialise_by_value(), and sampler_mod_get_rand_peer().

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RPS_sampler_elem_create()

struct RPS_SamplerElement * RPS_sampler_elem_create

(

void

)

Create a sampler element and initialise it.

In this implementation this means choosing an auth_key for later use in a hmac at random.

Returns

a newly created RPS_SamplerElement which currently holds no id.

Definition at line 75 of file gnunet-service-rps_sampler_elem.c.

{
  struct RPS_SamplerElement *s;
 
  s = GNUNET_new (struct RPS_SamplerElement);
 
  RPS_sampler_elem_reinit (s);
 
  return s;
}

References GNUNET_new, and RPS_sampler_elem_reinit().

Referenced by sampler_resize().

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RPS_sampler_elem_destroy()

void RPS_sampler_elem_destroy

(

struct RPS_SamplerElement *

sampler_elem

)

Destroy a sampler element.

Parameters

sampler_elem

the element to destroy

Definition at line 93 of file gnunet-service-rps_sampler_elem.c.

{
  GNUNET_free (sampler_elem);
}

References GNUNET_free.

Referenced by sampler_resize().

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RPS_sampler_elem_next()

void RPS_sampler_elem_next	(	struct RPS_SamplerElement *	sampler_elem,
		const struct GNUNET_PeerIdentity *	new_ID
	)

Update a sampler element with a PeerID.

Parameters

sampler_elem	The sampler element to update
new_ID	The PeerID to update with

Definition at line 106 of file gnunet-service-rps_sampler_elem.c.

{
  struct GNUNET_HashCode other_hash;
 
  sampler_elem->num_peers++;
 
  if (0 == GNUNET_memcmp (new_ID, &(sampler_elem->peer_id)))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Have already PeerID %s\n",
         GNUNET_i2s (&(sampler_elem->peer_id)));
  }
  else
  {
    GNUNET_CRYPTO_hmac (&sampler_elem->auth_key,
                        new_ID,
                        sizeof(struct GNUNET_PeerIdentity),
                        &other_hash);
 
    if (EMPTY == sampler_elem->is_empty)
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Got PeerID %s; Simply accepting (was empty previously).\n",
           GNUNET_i2s (new_ID));
      sampler_elem->peer_id = *new_ID;
      sampler_elem->peer_id_hash = other_hash;
 
      sampler_elem->num_change++;
    }
    else if (0 > GNUNET_CRYPTO_hash_cmp (&other_hash,
                                         &sampler_elem->peer_id_hash))
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG, "Discarding old PeerID %s\n",
           GNUNET_i2s (&sampler_elem->peer_id));
      sampler_elem->peer_id = *new_ID;
      sampler_elem->peer_id_hash = other_hash;
 
      sampler_elem->num_change++;
    }
    else
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG, "Keeping old PeerID %s\n",
           GNUNET_i2s (&sampler_elem->peer_id));
    }
  }
  sampler_elem->is_empty = NOT_EMPTY;
}

References RPS_SamplerElement::auth_key, EMPTY, GNUNET_CRYPTO_hash_cmp(), GNUNET_CRYPTO_hmac(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_i2s(), GNUNET_memcmp, RPS_SamplerElement::is_empty, LOG, NOT_EMPTY, RPS_SamplerElement::num_change, RPS_SamplerElement::num_peers, RPS_SamplerElement::peer_id, and RPS_SamplerElement::peer_id_hash.

Referenced by RPS_sampler_update().

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RPS_sampler_elem_set()

void RPS_sampler_elem_set	(	struct RPS_SamplerElement *	sampler_elem,
		struct GNUNET_CRYPTO_AuthKey	auth_key
	)

Set the min-wise independent function of the given sampler element.

Parameters

sampler_elem	the sampler element
auth_key	the key to use

Definition at line 162 of file gnunet-service-rps_sampler_elem.c.

{
  sampler_elem->auth_key = auth_key;
}

References RPS_SamplerElement::auth_key.