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/*
This file is part of GNUnet.
Copyright (C) 2009, 2010, 2011, 2016 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
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
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file nse/nse_api.c
* @brief api to get information from the network size estimation service
* @author Nathan Evans
*/
#include "platform.h"
#include "gnunet_constants.h"
#include "gnunet_arm_service.h"
#include "gnunet_hello_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_util_lib.h"
#include "gnunet_nse_service.h"
#include "nse.h"
#define LOG(kind,...) GNUNET_log_from (kind, "nse-api",__VA_ARGS__)
/**
* Handle for talking with the NSE service.
*/
struct GNUNET_NSE_Handle
{
/**
* Configuration to use.
*/
const struct GNUNET_CONFIGURATION_Handle *cfg;
/**
* Message queue (if available).
*/
struct GNUNET_MQ_Handle *mq;
/**
* Task doing exponential back-off trying to reconnect.
*/
struct GNUNET_SCHEDULER_Task *reconnect_task;
/**
* Time for next connect retry.
*/
struct GNUNET_TIME_Relative reconnect_delay;
/**
* Callback function to call when message is received.
*/
GNUNET_NSE_Callback recv_cb;
/**
* Closure to pass to @e recv_cb callback.
*/
void *recv_cb_cls;
};
/**
* Try again to connect to network size estimation service.
*
* @param cls closure with the `struct GNUNET_NSE_Handle *`
*/
static void
reconnect (void *cls);
/**
* Generic error handler, called with the appropriate
* error code and the same closure specified at the creation of
* the message queue.
* Not every message queue implementation supports an error handler.
*
* @param cls closure with the `struct GNUNET_NSE_Handle *`
* @param error error code
*/
static void
mq_error_handler (void *cls,
enum GNUNET_MQ_Error error)
{
struct GNUNET_NSE_Handle *h = cls;
GNUNET_MQ_destroy (h->mq);
h->mq = NULL;
h->reconnect_task
= GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
&reconnect,
h);
h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
}
/**
* Type of a function to call when we receive a message
* from the service.
*
* @param cls closure
* @param client_msg message received
*/
static void
handle_estimate (void *cls,
const struct GNUNET_NSE_ClientMessage *client_msg)
{
struct GNUNET_NSE_Handle *h = cls;
h->reconnect_delay = GNUNET_TIME_UNIT_ZERO;
h->recv_cb (h->recv_cb_cls,
GNUNET_TIME_absolute_ntoh (client_msg->timestamp),
GNUNET_ntoh_double (client_msg->size_estimate),
GNUNET_ntoh_double (client_msg->std_deviation));
}
/**
* Try again to connect to network size estimation service.
*
* @param cls the `struct GNUNET_NSE_Handle *`
*/
static void
reconnect (void *cls)
{
struct GNUNET_NSE_Handle *h = cls;
struct GNUNET_MQ_MessageHandler handlers[] = {
GNUNET_MQ_hd_fixed_size (estimate,
GNUNET_MESSAGE_TYPE_NSE_ESTIMATE,
struct GNUNET_NSE_ClientMessage,
h),
GNUNET_MQ_handler_end ()
};
struct GNUNET_MessageHeader *msg;
struct GNUNET_MQ_Envelope *env;
h->reconnect_task = NULL;
LOG (GNUNET_ERROR_TYPE_DEBUG,
"Connecting to network size estimation service.\n");
GNUNET_assert (NULL == h->mq);
h->mq = GNUNET_CLIENT_connect (h->cfg,
"nse",
handlers,
&mq_error_handler,
h);
if (NULL == h->mq)
return;
env = GNUNET_MQ_msg (msg,
GNUNET_MESSAGE_TYPE_NSE_START);
GNUNET_MQ_send (h->mq,
env);
}
/**
* Connect to the network size estimation service.
*
* @param cfg the configuration to use
* @param func funtion to call with network size estimate
* @param func_cls closure to pass to @a func
* @return handle to use
*/
struct GNUNET_NSE_Handle *
GNUNET_NSE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
GNUNET_NSE_Callback func,
void *func_cls)
{
struct GNUNET_NSE_Handle *h;
GNUNET_assert (NULL != func);
h = GNUNET_new (struct GNUNET_NSE_Handle);
h->cfg = cfg;
h->recv_cb = func;
h->recv_cb_cls = func_cls;
h->reconnect_delay = GNUNET_TIME_UNIT_ZERO;
reconnect (h);
if (NULL == h->mq)
{
GNUNET_free (h);
return NULL;
}
return h;
}
/**
* Disconnect from network size estimation service
*
* @param h handle to destroy
*/
void
GNUNET_NSE_disconnect (struct GNUNET_NSE_Handle *h)
{
if (NULL != h->reconnect_task)
{
GNUNET_SCHEDULER_cancel (h->reconnect_task);
h->reconnect_task = NULL;
}
if (NULL != h->mq)
{
GNUNET_MQ_destroy (h->mq);
h->mq = NULL;
}
GNUNET_free (h);
}
/* end of nse_api.c */
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