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/*
This file is part of GNUnet.
(C) 2009, 2010 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file dht/dht_api_find_peer.c
* @brief library to access the DHT to find peers
* @author Christian Grothoff
* @author Nathan Evans
*/
#include "platform.h"
#include "gnunet_constants.h"
#include "gnunet_arm_service.h"
#include "gnunet_protocols.h"
#include "gnunet_util_lib.h"
#include "gnunet_dht_service.h"
#include "dht.h"
/**
* Handle to control a find peer operation.
*/
struct GNUNET_DHT_FindPeerHandle
{
/**
* Handle to the actual route operation for the request
*/
struct GNUNET_DHT_RouteHandle *route_handle;
/**
* Iterator to call on data receipt
*/
GNUNET_DHT_FindPeerProcessor proc;
/**
* Closure for the iterator callback
*/
void *proc_cls;
};
/**
* Iterator called on each result obtained from a generic route
* operation
*
* @param cls closure
* @param key key that was used
* @param outgoing_path NULL-terminated array of pointers
* to the peers on reverse path
* (or NULL if not recorded)
* @param reply response
*/
static void
find_peer_reply_iterator (void *cls,
const GNUNET_HashCode *key,
const struct GNUNET_PeerIdentity * const *outgoing_path,
const struct GNUNET_MessageHeader *reply)
{
struct GNUNET_DHT_FindPeerHandle *find_peer_handle = cls;
const struct GNUNET_MessageHeader *hello;
if (ntohs (reply->type) != GNUNET_MESSAGE_TYPE_DHT_FIND_PEER_RESULT)
{
GNUNET_break (0);
return;
}
GNUNET_assert (ntohs (reply->size) >= sizeof (struct GNUNET_MessageHeader));
hello = (const struct GNUNET_MessageHeader *)&reply[1];
if (ntohs(hello->type) != GNUNET_MESSAGE_TYPE_HELLO)
{
GNUNET_break (0);
return;
}
find_peer_handle->proc (find_peer_handle->proc_cls,
(const struct GNUNET_HELLO_Message *)hello);
}
/**
* Perform an asynchronous FIND PEER operation on the DHT.
*
* @param handle handle to the DHT service
* @param timeout timeout for this request to be sent to the
* service
* @param options routing options for this message
* @param key the key to look up
* @param proc function to call on each result
* @param proc_cls closure for proc
* @return handle to stop the async get, NULL on error
*/
struct GNUNET_DHT_FindPeerHandle *
GNUNET_DHT_find_peer_start (struct GNUNET_DHT_Handle *handle,
struct GNUNET_TIME_Relative timeout,
const GNUNET_HashCode *key,
enum GNUNET_DHT_RouteOption options,
GNUNET_DHT_FindPeerProcessor proc,
void *proc_cls)
{
struct GNUNET_DHT_FindPeerHandle *find_peer_handle;
struct GNUNET_DHT_FindPeerMessage find_peer_msg;
find_peer_handle =
GNUNET_malloc (sizeof (struct GNUNET_DHT_FindPeerHandle));
find_peer_handle->proc = proc;
find_peer_handle->proc_cls = proc_cls;
find_peer_msg.header.size = htons(sizeof(struct GNUNET_DHT_FindPeerMessage));
find_peer_msg.header.type = htons(GNUNET_MESSAGE_TYPE_DHT_FIND_PEER);
find_peer_handle->route_handle =
GNUNET_DHT_route_start (handle, key,
0, options,
&find_peer_msg.header,
timeout,
&find_peer_reply_iterator, find_peer_handle,
NULL, NULL);
GNUNET_break (find_peer_handle->route_handle != NULL);
return find_peer_handle;
}
/**
* Stop async find peer. Frees associated resources.
*
* @param find_peer_handle GET operation to stop.
*/
void
GNUNET_DHT_find_peer_stop (struct GNUNET_DHT_FindPeerHandle *find_peer_handle)
{
GNUNET_DHT_route_stop (find_peer_handle->route_handle);
GNUNET_free (find_peer_handle);
}
/* end of dht_api_find_peer.c */
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