1 files changed, 938 insertions, 0 deletions

diff --git a/src/transport/transport_api2_core.c b/src/transport/transport_api2_core.c
new file mode 100644
index 000000000..78d8dcce0
--- /dev/null
+++ b/src/transport/transport_api2_core.c
@@ -0,0 +1,938 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2009-2013, 2016, 2018 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 transport/transport_api_core.c
+ * @brief library to access the transport service for message exchange
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_arm_service.h"
+#include "gnunet_hello_lib.h"
+#include "gnunet_protocols.h"
+#include "gnunet_transport_core_service.h"
+#include "transport.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "transport-api-core",__VA_ARGS__)
+
+/**
+ * How large to start with for the hashmap of neighbours.
+ */
+#define STARTING_NEIGHBOURS_SIZE 16
+
+
+/**
+ * Entry in hash table of all of our current (connected) neighbours.
+ */
+struct Neighbour
+{
+
+  /**
+   * Identity of this neighbour.
+   */
+  struct GNUNET_PeerIdentity id;
+
+  /**
+   * Overall transport handle.
+   */
+  struct GNUNET_TRANSPORT_CoreHandle *h;
+
+  /**
+   * Active message queue for the peer.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Envelope with the message we are currently transmitting (or NULL).
+   */
+  struct GNUNET_MQ_Envelope *env;
+
+  /**
+   * Closure for @e mq handlers.
+   */
+  void *handlers_cls;
+
+  /**
+   * Entry in our readyness heap (which is sorted by @e next_ready
+   * value).  NULL if there is no pending transmission request for
+   * this neighbour or if we're waiting for @e is_ready to become
+   * true AFTER the @e out_tracker suggested that this peer's quota
+   * has been satisfied (so once @e is_ready goes to #GNUNET_YES,
+   * we should immediately go back into the heap).
+   */
+  struct GNUNET_CONTAINER_HeapNode *hn;
+
+  /**
+   * Task to trigger MQ when we have enough bandwidth for the
+   * next transmission.
+   */
+  struct GNUNET_SCHEDULER_Task *timeout_task;
+
+  /**
+   * Outbound bandwidh tracker.
+   */
+  struct GNUNET_BANDWIDTH_Tracker out_tracker;
+
+  /**
+   * Sending consumed more bytes on wire than payload was announced
+   * This overhead is added to the delay of next sending operation
+   */
+  unsigned long long traffic_overhead;
+
+  /**
+   * Is this peer currently ready to receive a message?
+   */
+  int is_ready;
+
+  /**
+   * Size of the message in @e env.
+   */
+  uint16_t env_size;
+
+};
+
+
+
+/**
+ * Handle for the transport service (includes all of the
+ * state for the transport service).
+ */
+struct GNUNET_TRANSPORT_CoreHandle
+{
+
+  /**
+   * Closure for the callbacks.
+   */
+  void *cls;
+
+  /**
+   * Functions to call for received data (template for
+   * new message queues).
+   */
+  struct GNUNET_MQ_MessageHandler *handlers;
+
+  /**
+   * function to call on connect events
+   */
+  GNUNET_TRANSPORT_NotifyConnect nc_cb;
+
+  /**
+   * function to call on disconnect events
+   */
+  GNUNET_TRANSPORT_NotifyDisconnect nd_cb;
+
+  /**
+   * function to call on excess bandwidth events
+   */
+  GNUNET_TRANSPORT_NotifyExcessBandwidth neb_cb;
+
+  /**
+   * My client connection to the transport service.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * My configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Hash map of the current connected neighbours of this peer.
+   * Maps peer identities to `struct Neighbour` entries.
+   */
+  struct GNUNET_CONTAINER_MultiPeerMap *neighbours;
+
+  /**
+   * Peer identity as assumed by this process, or all zeros.
+   */
+  struct GNUNET_PeerIdentity self;
+
+  /**
+   * ID of the task trying to reconnect to the service.
+   */
+  struct GNUNET_SCHEDULER_Task *reconnect_task;
+
+  /**
+   * Delay until we try to reconnect.
+   */
+  struct GNUNET_TIME_Relative reconnect_delay;
+
+  /**
+   * Should we check that @e self matches what the service thinks?
+   * (if #GNUNET_NO, then @e self is all zeros!).
+   */
+  int check_self;
+
+};
+
+
+/**
+ * Function that will schedule the job that will try
+ * to connect us again to the client.
+ *
+ * @param h transport service to reconnect
+ */
+static void
+disconnect_and_schedule_reconnect (struct GNUNET_TRANSPORT_CoreHandle *h);
+
+
+/**
+ * Get the neighbour list entry for the given peer
+ *
+ * @param h our context
+ * @param peer peer to look up
+ * @return NULL if no such peer entry exists
+ */
+static struct Neighbour *
+neighbour_find (struct GNUNET_TRANSPORT_CoreHandle *h,
+                const struct GNUNET_PeerIdentity *peer)
+{
+  return GNUNET_CONTAINER_multipeermap_get (h->neighbours,
+                                            peer);
+}
+
+
+/**
+ * Function called by the bandwidth tracker if we have excess
+ * bandwidth.
+ *
+ * @param cls the `struct Neighbour` that has excess bandwidth
+ */
+static void
+notify_excess_cb (void *cls)
+{
+  struct Neighbour *n = cls;
+  struct GNUNET_TRANSPORT_CoreHandle *h = n->h;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Notifying CORE that more bandwidth is available for %s\n",
+       GNUNET_i2s (&n->id));
+
+  if (NULL != h->neb_cb)
+    h->neb_cb (h->cls,
+               &n->id,
+               n->handlers_cls);
+}
+
+
+/**
+ * Iterator over hash map entries, for deleting state of a neighbour.
+ *
+ * @param cls the `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param key peer identity
+ * @param value value in the hash map, the neighbour entry to delete
+ * @return #GNUNET_YES if we should continue to
+ *         iterate,
+ *         #GNUNET_NO if not.
+ */
+static int
+neighbour_delete (void *cls,
+                  const struct GNUNET_PeerIdentity *key,
+                  void *value)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *handle = cls;
+  struct Neighbour *n = value;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Dropping entry for neighbour `%s'.\n",
+       GNUNET_i2s (key));
+  GNUNET_BANDWIDTH_tracker_notification_stop (&n->out_tracker);
+  if (NULL != handle->nd_cb)
+    handle->nd_cb (handle->cls,
+                   &n->id,
+                   n->handlers_cls);
+  if (NULL != n->timeout_task)
+  {
+    GNUNET_SCHEDULER_cancel (n->timeout_task);
+    n->timeout_task = NULL;
+  }
+  if (NULL != n->env)
+  {
+    GNUNET_MQ_send_cancel (n->env);
+    n->env = NULL;
+  }
+  GNUNET_MQ_destroy (n->mq);
+  GNUNET_assert (NULL == n->mq);
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multipeermap_remove (handle->neighbours,
+                                                       key,
+                                                       n));
+  GNUNET_free (n);
+  return GNUNET_YES;
+}
+
+
+/**
+ * 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_TRANSPORT_CoreHandle *`
+ * @param error error code
+ */
+static void
+mq_error_handler (void *cls,
+                  enum GNUNET_MQ_Error error)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Error receiving from transport service, disconnecting temporarily.\n");
+  disconnect_and_schedule_reconnect (h);
+}
+
+
+/**
+ * A message from the handler's message queue to a neighbour was
+ * transmitted.  Now trigger (possibly delayed) notification of the
+ * neighbour's message queue that we are done and thus ready for
+ * the next message.
+ *
+ * @param cls the `struct Neighbour` where the message was sent
+ */
+static void
+notify_send_done_fin (void *cls)
+{
+  struct Neighbour *n = cls;
+
+  n->timeout_task = NULL;
+  n->is_ready = GNUNET_YES;
+  GNUNET_MQ_impl_send_continue (n->mq);
+}
+
+
+/**
+ * A message from the handler's message queue to a neighbour was
+ * transmitted.  Now trigger (possibly delayed) notification of the
+ * neighbour's message queue that we are done and thus ready for
+ * the next message.
+ *
+ * @param cls the `struct Neighbour` where the message was sent
+ */
+static void
+notify_send_done (void *cls)
+{
+  struct Neighbour *n = cls;
+  struct GNUNET_TIME_Relative delay;
+
+  n->timeout_task = NULL;
+  if (NULL != n->env)
+  {
+    GNUNET_BANDWIDTH_tracker_consume (&n->out_tracker,
+                                      n->env_size + n->traffic_overhead);
+    n->env = NULL;
+    n->traffic_overhead = 0;
+  }
+  delay = GNUNET_BANDWIDTH_tracker_get_delay (&n->out_tracker,
+                                              128);
+  if (0 == delay.rel_value_us)
+  {
+    n->is_ready = GNUNET_YES;
+    GNUNET_MQ_impl_send_continue (n->mq);
+    return;
+  }
+  GNUNET_MQ_impl_send_in_flight (n->mq);
+  /* cannot send even a small message without violating
+     quota, wait a before allowing MQ to send next message */
+  n->timeout_task = GNUNET_SCHEDULER_add_delayed (delay,
+                                                  &notify_send_done_fin,
+                                                  n);
+}
+
+
+/**
+ * Implement sending functionality of a message queue.
+ * Called one message at a time. Should send the @a msg
+ * to the transport service and then notify the queue
+ * once we are ready for the next one.
+ *
+ * @param mq the message queue
+ * @param msg the message to send
+ * @param impl_state state of the implementation
+ */
+static void
+mq_send_impl (struct GNUNET_MQ_Handle *mq,
+              const struct GNUNET_MessageHeader *msg,
+              void *impl_state)
+{
+  struct Neighbour *n = impl_state;
+  struct GNUNET_TRANSPORT_CoreHandle *h = n->h;
+  struct OutboundMessage *obm;
+  uint16_t msize;
+
+  GNUNET_assert (GNUNET_YES == n->is_ready);
+  msize = ntohs (msg->size);
+  if (msize >= GNUNET_MAX_MESSAGE_SIZE - sizeof (*obm))
+  {
+    GNUNET_break (0);
+    GNUNET_MQ_impl_send_continue (mq);
+    return;
+  }
+  GNUNET_assert (NULL == n->env);
+  n->env = GNUNET_MQ_msg_nested_mh (obm,
+                                    GNUNET_MESSAGE_TYPE_TRANSPORT_SEND,
+                                    msg);
+  obm->reserved = htonl (0);
+  obm->timeout = GNUNET_TIME_relative_hton (GNUNET_TIME_UNIT_MINUTES); /* FIXME: to be removed */
+  obm->peer = n->id;
+  GNUNET_assert (NULL == n->timeout_task);
+  n->is_ready = GNUNET_NO;
+  n->env_size = ntohs (msg->size);
+  GNUNET_MQ_notify_sent (n->env,
+                         &notify_send_done,
+                         n);
+  GNUNET_MQ_send (h->mq,
+                  n->env);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Queued message of type %u for neighbour `%s'.\n",
+       ntohs (msg->type),
+       GNUNET_i2s (&n->id));
+}
+
+
+/**
+ * Handle destruction of a message queue.  Implementations must not
+ * free @a mq, but should take care of @a impl_state.
+ *
+ * @param mq the message queue to destroy
+ * @param impl_state state of the implementation
+ */
+static void
+mq_destroy_impl (struct GNUNET_MQ_Handle *mq,
+                 void *impl_state)
+{
+  struct Neighbour *n = impl_state;
+
+  GNUNET_assert (mq == n->mq);
+  n->mq = NULL;
+}
+
+
+/**
+ * Implementation function that cancels the currently sent message.
+ * Should basically undo whatever #mq_send_impl() did.
+ *
+ * @param mq message queue
+ * @param impl_state state specific to the implementation
+ */
+static void
+mq_cancel_impl (struct GNUNET_MQ_Handle *mq,
+                void *impl_state)
+{
+  struct Neighbour *n = impl_state;
+
+  GNUNET_assert (GNUNET_NO == n->is_ready);
+  if (NULL != n->env)
+  {
+    GNUNET_MQ_send_cancel (n->env);
+    n->env = NULL;
+  }
+
+  n->is_ready = GNUNET_YES;
+}
+
+
+/**
+ * We had an error processing a message we forwarded from a peer to
+ * the CORE service.  We should just complain about it but otherwise
+ * continue processing.
+ *
+ * @param cls closure
+ * @param error error code
+ */
+static void
+peer_mq_error_handler (void *cls,
+                       enum GNUNET_MQ_Error error)
+{
+  /* struct Neighbour *n = cls; */
+
+  GNUNET_break_op (0);
+}
+
+
+/**
+ * The outbound quota has changed in a way that may require
+ * us to reset the timeout.  Update the timeout.
+ *
+ * @param cls the `struct Neighbour` for which the timeout changed
+ */
+static void
+outbound_bw_tracker_update (void *cls)
+{
+  struct Neighbour *n = cls;
+  struct GNUNET_TIME_Relative delay;
+
+  if (NULL == n->timeout_task)
+    return;
+  delay = GNUNET_BANDWIDTH_tracker_get_delay (&n->out_tracker,
+                                              128);
+  GNUNET_SCHEDULER_cancel (n->timeout_task);
+  n->timeout_task = GNUNET_SCHEDULER_add_delayed (delay,
+                                                  &notify_send_done,
+                                                  n);
+}
+
+
+/**
+ * Function we use for handling incoming connect messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_Handle *`
+ * @param cim message received
+ */
+static void
+handle_connect (void *cls,
+                const struct ConnectInfoMessage *cim)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  struct Neighbour *n;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Receiving CONNECT message for `%s' with quota %u\n",
+       GNUNET_i2s (&cim->id),
+       ntohl (cim->quota_out.value__));
+  n = neighbour_find (h,
+                      &cim->id);
+  if (NULL != n)
+  {
+    GNUNET_break (0);
+    disconnect_and_schedule_reconnect (h);
+    return;
+  }
+  n = GNUNET_new (struct Neighbour);
+  n->id = cim->id;
+  n->h = h;
+  n->is_ready = GNUNET_YES;
+  n->traffic_overhead = 0;
+  GNUNET_BANDWIDTH_tracker_init2 (&n->out_tracker,
+                                  &outbound_bw_tracker_update,
+                                  n,
+                                  GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
+                                  MAX_BANDWIDTH_CARRY_S,
+                                  &notify_excess_cb,
+                                  n);
+  GNUNET_assert (GNUNET_OK ==
+                 GNUNET_CONTAINER_multipeermap_put (h->neighbours,
+                                                    &n->id,
+                                                    n,
+                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+
+  GNUNET_BANDWIDTH_tracker_update_quota (&n->out_tracker,
+                                         cim->quota_out);
+  n->mq = GNUNET_MQ_queue_for_callbacks (&mq_send_impl,
+                                         &mq_destroy_impl,
+                                         &mq_cancel_impl,
+                                         n,
+                                         h->handlers,
+                                         &peer_mq_error_handler,
+                                         n);
+  if (NULL != h->nc_cb)
+  {
+    n->handlers_cls = h->nc_cb (h->cls,
+                                &n->id,
+                                n->mq);
+    GNUNET_MQ_set_handlers_closure (n->mq,
+                                    n->handlers_cls);
+  }
+}
+
+
+/**
+ * Function we use for handling incoming disconnect messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param dim message received
+ */
+static void
+handle_disconnect (void *cls,
+                   const struct DisconnectInfoMessage *dim)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  struct Neighbour *n;
+
+  GNUNET_break (ntohl (dim->reserved) == 0);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Receiving DISCONNECT message for `%s'.\n",
+       GNUNET_i2s (&dim->peer));
+  n = neighbour_find (h,
+                      &dim->peer);
+  if (NULL == n)
+  {
+    GNUNET_break (0);
+    disconnect_and_schedule_reconnect (h);
+    return;
+  }
+  GNUNET_assert (GNUNET_YES ==
+                 neighbour_delete (h,
+                                   &dim->peer,
+                                   n));
+}
+
+
+/**
+ * Function we use for handling incoming send-ok messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param okm message received
+ */
+static void
+handle_send_ok (void *cls,
+                const struct SendOkMessage *okm)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  struct Neighbour *n;
+  uint32_t bytes_msg;
+  uint32_t bytes_physical;
+
+  bytes_msg = ntohl (okm->bytes_msg);
+  bytes_physical = ntohl (okm->bytes_physical);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Receiving SEND_OK message, transmission to %s %s.\n",
+       GNUNET_i2s (&okm->peer),
+       (GNUNET_OK == ntohl (okm->success))
+       ? "succeeded"
+       : "failed");
+  n = neighbour_find (h,
+                      &okm->peer);
+  if (NULL == n)
+  {
+    /* We should never get a 'SEND_OK' for a peer that we are not
+       connected to */
+    GNUNET_break (0);
+    disconnect_and_schedule_reconnect (h);
+    return;
+  }
+  if (bytes_physical > bytes_msg)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Overhead for %u byte message was %u\n",
+         (unsigned int) bytes_msg,
+         (unsigned int) (bytes_physical - bytes_msg));
+    n->traffic_overhead += bytes_physical - bytes_msg;
+  }
+}
+
+
+/**
+ * Function we use for checking incoming "inbound" messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param im message received
+ */
+static int
+check_recv (void *cls,
+            const struct InboundMessage *im)
+{
+  const struct GNUNET_MessageHeader *imm;
+  uint16_t size;
+
+  size = ntohs (im->header.size) - sizeof (*im);
+  if (size < sizeof (struct GNUNET_MessageHeader))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  imm = (const struct GNUNET_MessageHeader *) &im[1];
+  if (ntohs (imm->size) != size)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function we use for handling incoming messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param im message received
+ */
+static void
+handle_recv (void *cls,
+             const struct InboundMessage *im)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  const struct GNUNET_MessageHeader *imm
+    = (const struct GNUNET_MessageHeader *) &im[1];
+  struct Neighbour *n;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received message of type %u with %u bytes from `%s'.\n",
+       (unsigned int) ntohs (imm->type),
+       (unsigned int) ntohs (imm->size),
+       GNUNET_i2s (&im->peer));
+  n = neighbour_find (h,
+                      &im->peer);
+  if (NULL == n)
+  {
+    GNUNET_break (0);
+    disconnect_and_schedule_reconnect (h);
+    return;
+  }
+  GNUNET_MQ_inject_message (n->mq,
+                            imm);
+}
+
+
+/**
+ * Function we use for handling incoming set quota messages.
+ *
+ * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
+ * @param msg message received
+ */
+static void
+handle_set_quota (void *cls,
+                  const struct QuotaSetMessage *qm)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  struct Neighbour *n;
+
+  n = neighbour_find (h,
+                      &qm->peer);
+  if (NULL == n)
+  {
+    GNUNET_break (0);
+    disconnect_and_schedule_reconnect (h);
+    return;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Receiving SET_QUOTA message for `%s' with quota %u\n",
+       GNUNET_i2s (&qm->peer),
+       (unsigned int) ntohl (qm->quota.value__));
+  GNUNET_BANDWIDTH_tracker_update_quota (&n->out_tracker,
+                                         qm->quota);
+}
+
+
+/**
+ * Try again to connect to transport service.
+ *
+ * @param cls the handle to the transport service
+ */
+static void
+reconnect (void *cls)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h = cls;
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_hd_fixed_size (connect,
+                             GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT,
+                             struct ConnectInfoMessage,
+                             h),
+    GNUNET_MQ_hd_fixed_size (disconnect,
+                             GNUNET_MESSAGE_TYPE_TRANSPORT_DISCONNECT,
+                             struct DisconnectInfoMessage,
+                             h),
+    GNUNET_MQ_hd_fixed_size (send_ok,
+                             GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK,
+                             struct SendOkMessage,
+                             h),
+    GNUNET_MQ_hd_var_size (recv,
+                           GNUNET_MESSAGE_TYPE_TRANSPORT_RECV,
+                           struct InboundMessage,
+                           h),
+    GNUNET_MQ_hd_fixed_size (set_quota,
+                             GNUNET_MESSAGE_TYPE_TRANSPORT_SET_QUOTA,
+                             struct QuotaSetMessage,
+                             h),
+    GNUNET_MQ_handler_end ()
+  };
+  struct GNUNET_MQ_Envelope *env;
+  struct StartMessage *s;
+  uint32_t options;
+
+  h->reconnect_task = NULL;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Connecting to transport service.\n");
+  GNUNET_assert (NULL == h->mq);
+  h->mq = GNUNET_CLIENT_connect (h->cfg,
+                                 "transport",
+                                 handlers,
+                                 &mq_error_handler,
+                                 h);
+  if (NULL == h->mq)
+    return;
+  env = GNUNET_MQ_msg (s,
+                       GNUNET_MESSAGE_TYPE_TRANSPORT_START);
+  options = 0;
+  if (h->check_self)
+    options |= 1;
+  if (NULL != h->handlers)
+    options |= 2;
+  s->options = htonl (options);
+  s->self = h->self;
+  GNUNET_MQ_send (h->mq,
+                  env);
+}
+
+
+/**
+ * Disconnect from the transport service.
+ *
+ * @param h transport service to reconnect
+ */
+static void
+disconnect (struct GNUNET_TRANSPORT_CoreHandle *h)
+{
+  GNUNET_CONTAINER_multipeermap_iterate (h->neighbours,
+                                         &neighbour_delete,
+                                         h);
+  if (NULL != h->mq)
+  {
+    GNUNET_MQ_destroy (h->mq);
+    h->mq = NULL;
+  }
+}
+
+
+/**
+ * Function that will schedule the job that will try
+ * to connect us again to the client.
+ *
+ * @param h transport service to reconnect
+ */
+static void
+disconnect_and_schedule_reconnect (struct GNUNET_TRANSPORT_CoreHandle *h)
+{
+  GNUNET_assert (NULL == h->reconnect_task);
+  disconnect (h);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Scheduling task to reconnect to transport service in %s.\n",
+       GNUNET_STRINGS_relative_time_to_string (h->reconnect_delay,
+                                               GNUNET_YES));
+  h->reconnect_task =
+      GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
+                                    &reconnect,
+                                    h);
+  h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
+}
+
+
+/**
+ * Checks if a given peer is connected to us and get the message queue.
+ *
+ * @param handle connection to transport service
+ * @param peer the peer to check
+ * @return NULL if disconnected, otherwise message queue for @a peer
+ */
+struct GNUNET_MQ_Handle *
+GNUNET_TRANSPORT_core_get_mq (struct GNUNET_TRANSPORT_CoreHandle *handle,
+                              const struct GNUNET_PeerIdentity *peer)
+{
+  struct Neighbour *n;
+
+  n = neighbour_find (handle,
+                      peer);
+  if (NULL == n)
+    return NULL;
+  return n->mq;
+}
+
+
+/**
+ * Connect to the transport service.  Note that the connection may
+ * complete (or fail) asynchronously.
+ *
+ * @param cfg configuration to use
+ * @param self our own identity (API should check that it matches
+ *             the identity found by transport), or NULL (no check)
+ * @param cls closure for the callbacks
+ * @param rec receive function to call
+ * @param nc function to call on connect events
+ * @param nd function to call on disconnect events
+ * @param neb function to call if we have excess bandwidth to a peer
+ * @return NULL on error
+ */
+struct GNUNET_TRANSPORT_CoreHandle *
+GNUNET_TRANSPORT_core_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                               const struct GNUNET_PeerIdentity *self,
+                               const struct GNUNET_MQ_MessageHandler *handlers,
+                               void *cls,
+                               GNUNET_TRANSPORT_NotifyConnect nc,
+                               GNUNET_TRANSPORT_NotifyDisconnect nd,
+                               GNUNET_TRANSPORT_NotifyExcessBandwidth neb)
+{
+  struct GNUNET_TRANSPORT_CoreHandle *h;
+  unsigned int i;
+
+  h = GNUNET_new (struct GNUNET_TRANSPORT_CoreHandle);
+  if (NULL != self)
+  {
+    h->self = *self;
+    h->check_self = GNUNET_YES;
+  }
+  h->cfg = cfg;
+  h->cls = cls;
+  h->nc_cb = nc;
+  h->nd_cb = nd;
+  h->neb_cb = neb;
+  h->reconnect_delay = GNUNET_TIME_UNIT_ZERO;
+  if (NULL != handlers)
+  {
+    for (i=0;NULL != handlers[i].cb; i++) ;
+    h->handlers = GNUNET_new_array (i + 1,
+                                    struct GNUNET_MQ_MessageHandler);
+    GNUNET_memcpy (h->handlers,
+                   handlers,
+                   i * sizeof (struct GNUNET_MQ_MessageHandler));
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Connecting to transport service\n");
+  reconnect (h);
+  if (NULL == h->mq)
+  {
+    GNUNET_free_non_null (h->handlers);
+    GNUNET_free (h);
+    return NULL;
+  }
+  h->neighbours =
+    GNUNET_CONTAINER_multipeermap_create (STARTING_NEIGHBOURS_SIZE,
+                                          GNUNET_YES);
+  return h;
+}
+
+
+/**
+ * Disconnect from the transport service.
+ *
+ * @param handle handle to the service as returned from #GNUNET_TRANSPORT_core_connect()
+ */
+void
+GNUNET_TRANSPORT_core_disconnect (struct GNUNET_TRANSPORT_CoreHandle *handle)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Transport disconnect called!\n");
+  /* this disconnects all neighbours... */
+  disconnect (handle);
+  /* and now we stop trying to connect again... */
+  if (NULL != handle->reconnect_task)
+  {
+    GNUNET_SCHEDULER_cancel (handle->reconnect_task);
+    handle->reconnect_task = NULL;
+  }
+  GNUNET_CONTAINER_multipeermap_destroy (handle->neighbours);
+  handle->neighbours = NULL;
+  GNUNET_free_non_null (handle->handlers);
+  handle->handlers = NULL;
+  GNUNET_free (handle);
+}
+
+
+/* end of transport_api_core.c */