separate ATS connectivity suggestions from ATS scheduling API

1 files changed, 356 insertions, 0 deletions

diff --git a/src/ats/ats_api_connectivity.c b/src/ats/ats_api_connectivity.c
new file mode 100644
index 000000000..9198118a4
--- /dev/null
+++ b/src/ats/ats_api_connectivity.c
@@ -0,0 +1,356 @@
+/*
+     This file is part of GNUnet.
+     (C) 2010-2015 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 ats/ats_api_connectivity.c
+ * @brief enable clients to ask ATS about establishing connections to peers
+ * @author Christian Grothoff
+ * @author Matthias Wachs
+ */
+#include "platform.h"
+#include "gnunet_ats_service.h"
+#include "ats.h"
+
+
+/**
+ * Handle for ATS address suggestion requests.
+ */
+struct GNUNET_ATS_ConnectivitySuggestHandle
+{
+  /**
+   * ID of the peer for which address suggestion was requested.
+   */
+  struct GNUNET_PeerIdentity id;
+
+  /**
+   * Connecitivity handle this suggestion handle belongs to.
+   */
+  struct GNUNET_ATS_ConnectivityHandle *ch;
+};
+
+
+/**
+ * Handle to the ATS subsystem for connectivity management.
+ */
+struct GNUNET_ATS_ConnectivityHandle
+{
+
+  /**
+   * Our configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Map with the identities of all the peers for which we would
+   * like to have address suggestions.  The key is the PID, the
+   * value is currently the `struct GNUNET_ATS_ConnectivitySuggestHandle`
+   */
+  struct GNUNET_CONTAINER_MultiPeerMap *sug_requests;
+
+  /**
+   * Connection to ATS service.
+   */
+  struct GNUNET_CLIENT_Connection *client;
+
+  /**
+   * Message queue for sending requests to the ATS service.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Task to trigger reconnect.
+   */
+  struct GNUNET_SCHEDULER_Task *task;
+
+};
+
+
+/**
+ * Re-establish the connection to the ATS service.
+ *
+ * @param ch handle to use to re-connect.
+ */
+static void
+reconnect (struct GNUNET_ATS_ConnectivityHandle *ch);
+
+
+/**
+ * Re-establish the connection to the ATS service.
+ *
+ * @param cls handle to use to re-connect.
+ * @param tc scheduler context
+ */
+static void
+reconnect_task (void *cls,
+                const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_ATS_ConnectivityHandle *ch = cls;
+
+  ch->task = NULL;
+  reconnect (ch);
+}
+
+
+/**
+ * Disconnect from ATS and then reconnect.
+ *
+ * @param ch our handle
+ */
+static void
+force_reconnect (struct GNUNET_ATS_ConnectivityHandle *ch)
+{
+  if (NULL != ch->mq)
+  {
+    GNUNET_MQ_destroy (ch->mq);
+    ch->mq = NULL;
+  }
+  if (NULL != ch->client)
+  {
+    GNUNET_CLIENT_disconnect (ch->client);
+    ch->client = NULL;
+  }
+  ch->task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
+                                           &reconnect_task,
+                                           ch);
+}
+
+
+/**
+ * We encountered an error handling the MQ to the
+ * ATS service.  Reconnect.
+ *
+ * @param cls the `struct GNUNET_ATS_ConnectivityHandle`
+ * @param error details about the error
+ */
+static void
+error_handler (void *cls,
+               enum GNUNET_MQ_Error error)
+{
+  struct GNUNET_ATS_ConnectivityHandle *ch = cls;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "ATS connection died (code %d), reconnecting\n",
+              (int) error);
+  force_reconnect (ch);
+}
+
+
+/**
+ * Transmit request for an address suggestion.
+ *
+ * @param cls the `struct GNUNET_ATS_ConnectivityHandle`
+ * @param peer peer to ask for an address suggestion for
+ * @param value the `struct GNUNET_ATS_SuggestHandle`
+ * @return #GNUNET_OK (continue to iterate), #GNUNET_SYSERR on
+ *         failure (message queue no longer exists)
+ */
+static int
+transmit_suggestion (void *cls,
+                     const struct GNUNET_PeerIdentity *peer,
+                     void *value)
+{
+  struct GNUNET_ATS_ConnectivityHandle *ch = cls;
+  struct GNUNET_MQ_Envelope *ev;
+  struct RequestAddressMessage *m;
+
+  if (NULL == ch->mq)
+    return GNUNET_SYSERR;
+  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_REQUEST_ADDRESS);
+  m->reserved = htonl (0);
+  m->peer = *peer;
+  GNUNET_MQ_send (ch->mq, ev);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Re-establish the connection to the ATS service.
+ *
+ * @param ch handle to use to re-connect.
+ */
+static void
+reconnect (struct GNUNET_ATS_ConnectivityHandle *ch)
+{
+  static const struct GNUNET_MQ_MessageHandler handlers[] =
+    { { NULL, 0, 0 } };
+  struct GNUNET_MQ_Envelope *ev;
+  struct ClientStartMessage *init;
+
+  GNUNET_assert (NULL == ch->client);
+  ch->client = GNUNET_CLIENT_connect ("ats", ch->cfg);
+  if (NULL == ch->client)
+  {
+    force_reconnect (ch);
+    return;
+  }
+  ch->mq = GNUNET_MQ_queue_for_connection_client (ch->client,
+                                                  handlers,
+                                                  &error_handler,
+                                                  ch);
+  ev = GNUNET_MQ_msg (init,
+                      GNUNET_MESSAGE_TYPE_ATS_START);
+  init->start_flag = htonl (START_FLAG_CONNECTION_SUGGESTION);
+  GNUNET_MQ_send (ch->mq, ev);
+  if (NULL == ch->mq)
+    return;
+  GNUNET_CONTAINER_multipeermap_iterate (ch->sug_requests,
+                                         &transmit_suggestion,
+                                         ch);
+}
+
+
+/**
+ * Initialize the ATS connectivity suggestion client handle.
+ *
+ * @param cfg configuration to use
+ * @return ats connectivity handle, NULL on error
+ */
+struct GNUNET_ATS_ConnectivityHandle *
+GNUNET_ATS_connectivity_init (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_ATS_ConnectivityHandle *ch;
+
+  ch = GNUNET_new (struct GNUNET_ATS_ConnectivityHandle);
+  ch->cfg = cfg;
+  ch->sug_requests = GNUNET_CONTAINER_multipeermap_create (32,
+                                                           GNUNET_YES);
+  reconnect (ch);
+  return ch;
+}
+
+
+/**
+ * Function called to free all `struct GNUNET_ATS_SuggestHandles`
+ * in the map.
+ *
+ * @param cls NULL
+ * @param key the key
+ * @param value the value to free
+ * @return #GNUNET_OK (continue to iterate)
+ */
+static int
+free_sug_handle (void *cls,
+                 const struct GNUNET_PeerIdentity *key,
+                 void *value)
+{
+  struct GNUNET_ATS_ConnectivitySuggestHandle *cur = value;
+
+  GNUNET_free (cur);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Client is done with ATS connectivity management, release resources.
+ *
+ * @param ch handle to release
+ */
+void
+GNUNET_ATS_connectivity_done (struct GNUNET_ATS_ConnectivityHandle *ch)
+{
+  if (NULL != ch->mq)
+  {
+    GNUNET_MQ_destroy (ch->mq);
+    ch->mq = NULL;
+  }
+  if (NULL != ch->client)
+  {
+    GNUNET_CLIENT_disconnect (ch->client);
+    ch->client = NULL;
+  }
+  if (NULL != ch->task)
+  {
+    GNUNET_SCHEDULER_cancel (ch->task);
+    ch->task = NULL;
+  }
+  GNUNET_CONTAINER_multipeermap_iterate (ch->sug_requests,
+                                         &free_sug_handle,
+                                         NULL);
+  GNUNET_CONTAINER_multipeermap_destroy (ch->sug_requests);
+  GNUNET_free (ch);
+}
+
+
+/**
+ * We would like to receive address suggestions for a peer. ATS will
+ * respond with a call to the continuation immediately containing an address or
+ * no address if none is available. ATS can suggest more addresses until we call
+ * #GNUNET_ATS_connectivity_suggest_cancel().
+ *
+ * @param ch handle
+ * @param peer identity of the peer we need an address for
+ * @return suggest handle, NULL if a request is already pending
+ */
+struct GNUNET_ATS_ConnectivitySuggestHandle *
+GNUNET_ATS_connectivity_suggest (struct GNUNET_ATS_ConnectivityHandle *ch,
+                                 const struct GNUNET_PeerIdentity *peer)
+{
+  struct GNUNET_ATS_ConnectivitySuggestHandle *s;
+
+  s = GNUNET_new (struct GNUNET_ATS_ConnectivitySuggestHandle);
+  s->ch = ch;
+  s->id = *peer;
+  if (GNUNET_OK !=
+      GNUNET_CONTAINER_multipeermap_put (ch->sug_requests,
+                                         &s->id,
+                                         s,
+                                         GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  if (NULL == ch->mq)
+    return s;
+  (void) transmit_suggestion (ch,
+                              &s->id,
+                              s);
+  return s;
+}
+
+
+/**
+ * We no longer care about being connected to a peer.
+ *
+ * @param sh handle to stop
+ */
+void
+GNUNET_ATS_connectivity_suggest_cancel (struct GNUNET_ATS_ConnectivitySuggestHandle *sh)
+{
+  struct GNUNET_ATS_ConnectivityHandle *ch = sh->ch;
+  struct GNUNET_MQ_Envelope *ev;
+  struct RequestAddressMessage *m;
+
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_CONTAINER_multipeermap_remove (ch->sug_requests,
+                                                       &sh->id,
+                                                       sh));
+  if (NULL == ch->mq)
+  {
+    GNUNET_free (sh);
+    return;
+  }
+  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_REQUEST_ADDRESS_CANCEL);
+  m->reserved = htonl (0);
+  m->peer = sh->id;
+  GNUNET_MQ_send (ch->mq, ev);
+  GNUNET_free (sh);
+}
+
+
+/* end of ats_api_connectivity.c */