1 files changed, 208 insertions, 0 deletions

diff --git a/src/service/nse/nse_api.c b/src/service/nse/nse_api.c
new file mode 100644
index 000000000..7f3e03b98
--- /dev/null
+++ b/src/service/nse/nse_api.c
@@ -0,0 +1,208 @@
+/*
+     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/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @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_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;
+
+  (void) error;
+  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 function 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 */