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/*
This file is part of GNUnet.
Copyright (C) 2009-2013 GNUnet e.V.
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., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file gns/gnunet-service-gns_reverser.c
* @brief GNUnet GNS service
* @author Martin Schanzenbach
*/
#include "platform.h"
#include "gnunet_gns_service.h"
#include "gnunet-service-gns_resolver.h"
#include "gnunet-service-gns_reverser.h"
struct ReverseTreeNode
{
/**
* DLL
*/
struct ReverseTreeNode *next;
/**
* DLL
*/
struct ReverseTreeNode *prev;
/**
* Resolved name until now
*/
char *name;
/**
* Depth of the resolution at this node
*/
uint8_t depth;
/**
* The pkey of the namespace
*/
struct GNUNET_CRYPTO_EcdsaPublicKey pkey;
};
struct GNS_ReverserHandle
{
/**
* GNS resolver handle
*/
struct GNS_ResolverHandle *rh;
/**
* The authority to look for
*/
struct GNUNET_CRYPTO_EcdsaPublicKey authority;
/**
* Resolution candidate queue
*/
struct ReverseTreeNode *node_queue_head;
/**
* Resolution candidate queue
*/
struct ReverseTreeNode *node_queue_tail;
/**
* Max depth for the resolution
*/
uint8_t max_depth;
/**
* Result callback
*/
GNS_ReverseResultProcessor proc;
/**
* Callback closure
*/
void *proc_cls;
};
void
cleanup_handle (struct GNS_ReverserHandle *rh)
{
struct ReverseTreeNode *rtn;
for (rtn = rh->node_queue_head; NULL != rtn; rtn = rh->node_queue_head)
{
if (NULL != rtn->name)
GNUNET_free (rtn->name);
GNUNET_CONTAINER_DLL_remove (rh->node_queue_head,
rh->node_queue_tail,
rtn);
GNUNET_free (rtn);
}
}
void
handle_gns_result (void *cls,
uint32_t rd_count,
const struct GNUNET_GNSRECORD_Data *rd)
{
struct GNS_ReverserHandle *rh = cls;
const struct GNUNET_GNSRECORD_ReverseRecord *rr;
struct ReverseTreeNode *rtn;
char *result;
const char *name;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Got result (%d)\n", rd_count);
for (int i = 0; i < rd_count; i++)
{
/**
* Check if we are in the delegation set
*/
if (GNUNET_GNSRECORD_TYPE_REVERSE != rd[i].record_type)
continue;
rr = rd[i].data;
name = (const char*) &rr[1];
if (0 == memcmp (&rh->authority,
&rr->pkey,
sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)))
{
//Found!
GNUNET_asprintf (&result,
"%s.%s.gnu",
rh->node_queue_head->name,
name);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Found path from %s\n", result);
rh->proc (rh->proc_cls, result);
cleanup_handle (rh);
GNUNET_free (result);
return;
} else {
if (rh->node_queue_head->depth >= rh->max_depth)
break;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Found REVERSE from %s\n", name);
rtn = GNUNET_new (struct ReverseTreeNode);
if (NULL == rh->node_queue_head->name)
rtn->name = GNUNET_strdup (name);
else
GNUNET_asprintf (&rtn->name,
"%s.%s",
rh->node_queue_head->name,
name);
rtn->depth = rh->node_queue_head->depth + 1;
rtn->pkey = rr->pkey;
GNUNET_CONTAINER_DLL_insert_tail (rh->node_queue_head,
rh->node_queue_tail,
rtn);
}
}
/**
* Done here remove node from queue
*/
rtn = rh->node_queue_head;
GNUNET_CONTAINER_DLL_remove (rh->node_queue_head,
rh->node_queue_tail,
rtn);
if (NULL == rh->node_queue_head)
{
//No luck
rh->proc (rh->proc_cls, NULL);
cleanup_handle (rh);
return;
}
rh->rh = GNS_resolver_lookup (&rh->node_queue_head->pkey,
GNUNET_GNSRECORD_TYPE_REVERSE,
"+.gnu",
NULL,
GNUNET_GNS_LO_DEFAULT,
&handle_gns_result,
rh);
}
struct GNS_ReverserHandle *
GNS_reverse_lookup (const struct GNUNET_CRYPTO_EcdsaPublicKey *target,
const struct GNUNET_CRYPTO_EcdsaPublicKey *authority,
GNS_ReverseResultProcessor proc,
void *proc_cls)
{
struct GNS_ReverserHandle *rh;
struct ReverseTreeNode *rtn;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Starting reverse resolution\n");
rh = GNUNET_new (struct GNS_ReverserHandle);
rh->proc = proc;
rh->proc_cls = proc_cls;
rtn = GNUNET_new (struct ReverseTreeNode);
rtn->name = NULL;
rtn->pkey = *target;
rtn->depth = 0;
GNUNET_CONTAINER_DLL_insert (rh->node_queue_head,
rh->node_queue_tail,
rtn);
rh->authority = *authority;
rh->max_depth = 3; //TODO make argument
rh->rh = GNS_resolver_lookup (target,
GNUNET_GNSRECORD_TYPE_REVERSE,
"+.gnu",
NULL,
GNUNET_GNS_LO_DEFAULT,
&handle_gns_result,
rh);
return rh;
}
/**
* Cancel active resolution (i.e. client disconnected).
*
* @param rh resolution to abort
*/
void
GNS_reverse_lookup_cancel (struct GNS_ReverserHandle *rh)
{
cleanup_handle (rh);
return;
}
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