1 files changed, 1763 insertions, 35 deletions

diff --git a/src/rps/gnunet-service-rps.c b/src/rps/gnunet-service-rps.c
index 0a4543b30..ec70075cf 100644
--- a/src/rps/gnunet-service-rps.c
+++ b/src/rps/gnunet-service-rps.c
@@ -33,7 +33,6 @@
 #include "rps-test_util.h"
 #include "gnunet-service-rps_sampler.h"
 #include "gnunet-service-rps_custommap.h"
-#include "gnunet-service-rps_peers.h"
 #include "gnunet-service-rps_view.h"
 
 #include <math.h>
@@ -66,6 +65,1728 @@ static const struct GNUNET_CONFIGURATION_Handle *cfg;
 static struct GNUNET_PeerIdentity own_identity;
 
 
+
+/***********************************************************************
+ * Old gnunet-service-rps_peers.c
+***********************************************************************/
+
+/**
+ * Set a peer flag of given peer context.
+ */
+#define set_peer_flag(peer_ctx, mask) ((peer_ctx->peer_flags) |= (mask))
+
+/**
+ * Get peer flag of given peer context.
+ */
+#define check_peer_flag_set(peer_ctx, mask)\
+  ((peer_ctx->peer_flags) & (mask) ? GNUNET_YES : GNUNET_NO)
+
+/**
+ * Unset flag of given peer context.
+ */
+#define unset_peer_flag(peer_ctx, mask) ((peer_ctx->peer_flags) &= ~(mask))
+
+/**
+ * Set a channel flag of given channel context.
+ */
+#define set_channel_flag(channel_flags, mask) ((*channel_flags) |= (mask))
+
+/**
+ * Get channel flag of given channel context.
+ */
+#define check_channel_flag_set(channel_flags, mask)\
+  ((*channel_flags) & (mask) ? GNUNET_YES : GNUNET_NO)
+
+/**
+ * Unset flag of given channel context.
+ */
+#define unset_channel_flag(channel_flags, mask) ((*channel_flags) &= ~(mask))
+
+
+
+/**
+ * Pending operation on peer consisting of callback and closure
+ *
+ * When an operation cannot be executed right now this struct is used to store
+ * the callback and closure for later execution.
+ */
+struct PeerPendingOp
+{
+  /**
+   * Callback
+   */
+  PeerOp op;
+
+  /**
+   * Closure
+   */
+  void *op_cls;
+};
+
+/**
+ * List containing all messages that are yet to be send
+ *
+ * This is used to keep track of all messages that have not been sent yet. When
+ * a peer is to be removed the pending messages can be removed properly.
+ */
+struct PendingMessage
+{
+  /**
+   * DLL next, prev
+   */
+  struct PendingMessage *next;
+  struct PendingMessage *prev;
+
+  /**
+   * The envelope to the corresponding message
+   */
+  struct GNUNET_MQ_Envelope *ev;
+
+  /**
+   * The corresponding context
+   */
+  struct PeerContext *peer_ctx;
+
+  /**
+   * The message type
+   */
+  const char *type;
+};
+
+/**
+ * Struct used to keep track of other peer's status
+ *
+ * This is stored in a multipeermap.
+ * It contains information such as cadet channels, a message queue for sending,
+ * status about the channels, the pending operations on this peer and some flags
+ * about the status of the peer itself. (live, valid, ...)
+ */
+struct PeerContext
+{
+  /**
+   * Message queue open to client
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Channel open to client.
+   */
+  struct GNUNET_CADET_Channel *send_channel;
+
+  /**
+   * Flags to the sending channel
+   */
+  uint32_t *send_channel_flags;
+
+  /**
+   * Channel open from client.
+   */
+  struct GNUNET_CADET_Channel *recv_channel; // unneeded?
+
+  /**
+   * Flags to the receiving channel
+   */
+  uint32_t *recv_channel_flags;
+
+  /**
+   * Array of pending operations on this peer.
+   */
+  struct PeerPendingOp *pending_ops;
+
+  /**
+   * Handle to the callback given to cadet_ntfy_tmt_rdy()
+   *
+   * To be canceled on shutdown.
+   */
+  struct PendingMessage *liveliness_check_pending;
+
+  /**
+   * Number of pending operations.
+   */
+  unsigned int num_pending_ops;
+
+  /**
+   * Identity of the peer
+   */
+  struct GNUNET_PeerIdentity peer_id;
+
+  /**
+   * Flags indicating status of peer
+   */
+  uint32_t peer_flags;
+
+  /**
+   * Last time we received something from that peer.
+   */
+  struct GNUNET_TIME_Absolute last_message_recv;
+
+  /**
+   * Last time we received a keepalive message.
+   */
+  struct GNUNET_TIME_Absolute last_keepalive;
+
+  /**
+   * DLL with all messages that are yet to be sent
+   */
+  struct PendingMessage *pending_messages_head;
+  struct PendingMessage *pending_messages_tail;
+
+  /**
+   * This is pobably followed by 'statistical' data (when we first saw
+   * him, how did we get his ID, how many pushes (in a timeinterval),
+   * ...)
+   */
+};
+
+/**
+ * @brief Closure to #valid_peer_iterator
+ */
+struct PeersIteratorCls
+{
+  /**
+   * Iterator function
+   */
+  PeersIterator iterator;
+
+  /**
+   * Closure to iterator
+   */
+  void *cls;
+};
+
+/**
+ * @brief Hashmap of valid peers.
+ */
+static struct GNUNET_CONTAINER_MultiPeerMap *valid_peers;
+
+/**
+ * @brief Maximum number of valid peers to keep.
+ * TODO read from config
+ */
+static uint32_t num_valid_peers_max = UINT32_MAX;
+
+/**
+ * @brief Filename of the file that stores the valid peers persistently.
+ */
+static char *filename_valid_peers;
+
+/**
+ * Set of all peers to keep track of them.
+ */
+static struct GNUNET_CONTAINER_MultiPeerMap *peer_map;
+
+/**
+ * Cadet handle.
+ */
+static struct GNUNET_CADET_Handle *cadet_handle;
+
+
+
+/**
+ * @brief Get the #PeerContext associated with a peer
+ *
+ * @param peer the peer id
+ *
+ * @return the #PeerContext
+ */
+static struct PeerContext *
+get_peer_ctx (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *ctx;
+  int ret;
+
+  ret = GNUNET_CONTAINER_multipeermap_contains (peer_map, peer);
+  GNUNET_assert (GNUNET_YES == ret);
+  ctx = GNUNET_CONTAINER_multipeermap_get (peer_map, peer);
+  GNUNET_assert (NULL != ctx);
+  return ctx;
+}
+
+int
+Peers_check_peer_known (const struct GNUNET_PeerIdentity *peer);
+
+/**
+ * @brief Create a new #PeerContext and insert it into the peer map
+ *
+ * @param peer the peer to create the #PeerContext for
+ *
+ * @return the #PeerContext
+ */
+static struct PeerContext *
+create_peer_ctx (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *ctx;
+  int ret;
+
+  GNUNET_assert (GNUNET_NO == Peers_check_peer_known (peer));
+
+  ctx = GNUNET_new (struct PeerContext);
+  ctx->peer_id = *peer;
+  ctx->send_channel_flags = GNUNET_new (uint32_t);
+  ctx->recv_channel_flags = GNUNET_new (uint32_t);
+  ret = GNUNET_CONTAINER_multipeermap_put (peer_map, peer, ctx,
+      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+  GNUNET_assert (GNUNET_OK == ret);
+  return ctx;
+}
+
+
+/**
+ * @brief Create or get a #PeerContext
+ *
+ * @param peer the peer to get the associated context to
+ *
+ * @return the context
+ */
+static struct PeerContext *
+create_or_get_peer_ctx (const struct GNUNET_PeerIdentity *peer)
+{
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {
+    return create_peer_ctx (peer);
+  }
+  return get_peer_ctx (peer);
+}
+
+void
+Peers_unset_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags);
+
+void
+Peers_set_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags);
+
+/**
+ * @brief Check whether we have a connection to this @a peer
+ *
+ * Also sets the #Peers_ONLINE flag accordingly
+ *
+ * @param peer the peer in question
+ *
+ * @return #GNUNET_YES if we are connected
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_check_connected (const struct GNUNET_PeerIdentity *peer)
+{
+  const struct PeerContext *peer_ctx;
+
+  /* If we don't know about this peer we don't know whether it's online */
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {
+    return GNUNET_NO;
+  }
+  /* Get the context */
+  peer_ctx = get_peer_ctx (peer);
+  /* If we have no channel to this peer we don't know whether it's online */
+  if ( (NULL == peer_ctx->send_channel) &&
+       (NULL == peer_ctx->recv_channel) )
+  {
+    Peers_unset_peer_flag (peer, Peers_ONLINE);
+    return GNUNET_NO;
+  }
+  /* Otherwise (if we have a channel, we know that it's online */
+  Peers_set_peer_flag (peer, Peers_ONLINE);
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief The closure to #get_rand_peer_iterator.
+ */
+struct GetRandPeerIteratorCls
+{
+  /**
+   * @brief The index of the peer to return.
+   * Will be decreased until 0.
+   * Then current peer is returned.
+   */
+  uint32_t index;
+
+  /**
+   * @brief Pointer to peer to return.
+   */
+  const struct GNUNET_PeerIdentity *peer;
+};
+
+
+/**
+ * @brief Iterator function for #get_random_peer_from_peermap.
+ *
+ * Implements #GNUNET_CONTAINER_PeerMapIterator.
+ * Decreases the index until the index is null.
+ * Then returns the current peer.
+ *
+ * @param cls the #GetRandPeerIteratorCls containing index and peer
+ * @param peer current peer
+ * @param value unused
+ *
+ * @return  #GNUNET_YES if we should continue to
+ *          iterate,
+ *          #GNUNET_NO if not.
+ */
+static int
+get_rand_peer_iterator (void *cls,
+                        const struct GNUNET_PeerIdentity *peer,
+                        void *value)
+{
+  struct GetRandPeerIteratorCls *iterator_cls = cls;
+  if (0 >= iterator_cls->index)
+  {
+    iterator_cls->peer = peer;
+    return GNUNET_NO;
+  }
+  iterator_cls->index--;
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief Get a random peer from @a peer_map
+ *
+ * @param peer_map the peer_map to get the peer from
+ *
+ * @return a random peer
+ */
+static const struct GNUNET_PeerIdentity *
+get_random_peer_from_peermap (const struct
+                              GNUNET_CONTAINER_MultiPeerMap *peer_map)
+{
+  struct GetRandPeerIteratorCls *iterator_cls;
+  const struct GNUNET_PeerIdentity *ret;
+
+  iterator_cls = GNUNET_new (struct GetRandPeerIteratorCls);
+  iterator_cls->index = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
+      GNUNET_CONTAINER_multipeermap_size (peer_map));
+  (void) GNUNET_CONTAINER_multipeermap_iterate (valid_peers,
+                                                get_rand_peer_iterator,
+                                                iterator_cls);
+  ret = iterator_cls->peer;
+  GNUNET_free (iterator_cls);
+  return ret;
+}
+
+
+/**
+ * @brief Add a given @a peer to valid peers.
+ *
+ * If valid peers are already #num_valid_peers_max, delete a peer previously.
+ *
+ * @param peer the peer that is added to the valid peers.
+ *
+ * @return #GNUNET_YES if no other peer had to be removed
+ *         #GNUNET_NO  otherwise
+ */
+static int
+add_valid_peer (const struct GNUNET_PeerIdentity *peer)
+{
+  const struct GNUNET_PeerIdentity *rand_peer;
+  int ret;
+
+  ret = GNUNET_YES;
+  while (GNUNET_CONTAINER_multipeermap_size (valid_peers) >= num_valid_peers_max)
+  {
+    rand_peer = get_random_peer_from_peermap (valid_peers);
+    GNUNET_CONTAINER_multipeermap_remove_all (valid_peers, rand_peer);
+    ret = GNUNET_NO;
+  }
+  (void) GNUNET_CONTAINER_multipeermap_put (valid_peers, peer, NULL,
+      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+  return ret;
+}
+
+
+/**
+ * @brief Set the peer flag to living and
+ *        call the pending operations on this peer.
+ *
+ * Also adds peer to #valid_peers.
+ *
+ * @param peer_ctx the #PeerContext of the peer to set live
+ */
+static void
+set_peer_live (struct PeerContext *peer_ctx)
+{
+  struct GNUNET_PeerIdentity *peer;
+  unsigned int i;
+
+  peer = &peer_ctx->peer_id;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "Peer %s is live and valid, calling %i pending operations on it\n",
+      GNUNET_i2s (peer),
+      peer_ctx->num_pending_ops);
+
+  if (NULL != peer_ctx->liveliness_check_pending)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Removing pending liveliness check for peer %s\n",
+         GNUNET_i2s (&peer_ctx->peer_id));
+    // TODO wait until cadet sets mq->cancel_impl
+    //GNUNET_MQ_send_cancel (peer_ctx->liveliness_check_pending->ev);
+    GNUNET_free (peer_ctx->liveliness_check_pending);
+    peer_ctx->liveliness_check_pending = NULL;
+  }
+
+  (void) add_valid_peer (peer);
+  set_peer_flag (peer_ctx, Peers_ONLINE);
+
+  /* Call pending operations */
+  for (i = 0; i < peer_ctx->num_pending_ops; i++)
+  {
+    peer_ctx->pending_ops[i].op (peer_ctx->pending_ops[i].op_cls, peer);
+  }
+  GNUNET_array_grow (peer_ctx->pending_ops, peer_ctx->num_pending_ops, 0);
+}
+
+static void
+cleanup_destroyed_channel (void *cls,
+                           const struct GNUNET_CADET_Channel *channel);
+
+/* Declaration of handlers */
+static void
+handle_peer_check (void *cls,
+                   const struct GNUNET_MessageHeader *msg);
+
+static void
+handle_peer_push (void *cls,
+                  const struct GNUNET_MessageHeader *msg);
+
+static void
+handle_peer_pull_request (void *cls,
+                          const struct GNUNET_MessageHeader *msg);
+
+static int
+check_peer_pull_reply (void *cls,
+                       const struct GNUNET_RPS_P2P_PullReplyMessage *msg);
+
+static void
+handle_peer_pull_reply (void *cls,
+                        const struct GNUNET_RPS_P2P_PullReplyMessage *msg);
+
+/* End declaration of handlers */
+
+
+/**
+ * @brief Get the channel of a peer. If not existing, create.
+ *
+ * @param peer the peer id
+ * @return the #GNUNET_CADET_Channel used to send data to @a peer
+ */
+struct GNUNET_CADET_Channel *
+get_channel (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+  struct GNUNET_HashCode port;
+  /* There exists a copy-paste-clone in run() */
+  struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
+    GNUNET_MQ_hd_fixed_size (peer_check,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_CHECK_LIVE,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_fixed_size (peer_push,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_PUSH,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_fixed_size (peer_pull_request,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REQUEST,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_var_size (peer_pull_reply,
+                           GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REPLY,
+                           struct GNUNET_RPS_P2P_PullReplyMessage,
+                           NULL),
+    GNUNET_MQ_handler_end ()
+  };
+
+
+  peer_ctx = get_peer_ctx (peer);
+  if (NULL == peer_ctx->send_channel)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Trying to establish channel to peer %s\n",
+         GNUNET_i2s (peer));
+    GNUNET_CRYPTO_hash (GNUNET_APPLICATION_PORT_RPS,
+                        strlen (GNUNET_APPLICATION_PORT_RPS),
+                        &port);
+    peer_ctx->send_channel =
+      GNUNET_CADET_channel_create (cadet_handle,
+                                   (struct GNUNET_PeerIdentity *) peer, /* context */
+                                   peer,
+                                   &port,
+                                   GNUNET_CADET_OPTION_RELIABLE,
+                                   NULL, /* WindowSize handler */
+                                   cleanup_destroyed_channel, /* Disconnect handler */
+                                   cadet_handlers);
+  }
+  GNUNET_assert (NULL != peer_ctx->send_channel);
+  return peer_ctx->send_channel;
+}
+
+
+/**
+ * Get the message queue (#GNUNET_MQ_Handle) of a specific peer.
+ *
+ * If we already have a message queue open to this client,
+ * simply return it, otherways create one.
+ *
+ * @param peer the peer to get the mq to
+ * @return the #GNUNET_MQ_Handle
+ */
+static struct GNUNET_MQ_Handle *
+get_mq (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+
+  if (NULL == peer_ctx->mq)
+  {
+    (void) get_channel (peer);
+    peer_ctx->mq = GNUNET_CADET_get_mq (peer_ctx->send_channel);
+  }
+  return peer_ctx->mq;
+}
+
+
+/**
+ * @brief This is called in response to the first message we sent as a
+ * liveliness check.
+ *
+ * @param cls #PeerContext of peer with pending liveliness check
+ */
+static void
+mq_liveliness_check_successful (void *cls)
+{
+  struct PeerContext *peer_ctx = cls;
+
+  if (NULL != peer_ctx->liveliness_check_pending)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+        "Liveliness check for peer %s was successfull\n",
+        GNUNET_i2s (&peer_ctx->peer_id));
+    GNUNET_free (peer_ctx->liveliness_check_pending);
+    peer_ctx->liveliness_check_pending = NULL;
+    set_peer_live (peer_ctx);
+  }
+}
+
+/**
+ * Issue a check whether peer is live
+ *
+ * @param peer_ctx the context of the peer
+ */
+static void
+check_peer_live (struct PeerContext *peer_ctx)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Get informed about peer %s getting live\n",
+       GNUNET_i2s (&peer_ctx->peer_id));
+
+  struct GNUNET_MQ_Handle *mq;
+  struct GNUNET_MQ_Envelope *ev;
+
+  ev = GNUNET_MQ_msg_header (GNUNET_MESSAGE_TYPE_RPS_PP_CHECK_LIVE);
+  peer_ctx->liveliness_check_pending = GNUNET_new (struct PendingMessage);
+  peer_ctx->liveliness_check_pending->ev = ev;
+  peer_ctx->liveliness_check_pending->peer_ctx = peer_ctx;
+  peer_ctx->liveliness_check_pending->type = "Check liveliness";
+  mq = get_mq (&peer_ctx->peer_id);
+  GNUNET_MQ_notify_sent (ev,
+                         mq_liveliness_check_successful,
+                         peer_ctx);
+  GNUNET_MQ_send (mq, ev);
+}
+
+/**
+ * @brief Add an envelope to a message passed to mq to list of pending messages
+ *
+ * @param peer peer the message was sent to
+ * @param ev envelope to the message
+ * @param type type of the message to be sent
+ * @return pointer to pending message
+ */
+static struct PendingMessage *
+insert_pending_message (const struct GNUNET_PeerIdentity *peer,
+                        struct GNUNET_MQ_Envelope *ev,
+                        const char *type)
+{
+  struct PendingMessage *pending_msg;
+  struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+  pending_msg = GNUNET_new (struct PendingMessage);
+  pending_msg->ev = ev;
+  pending_msg->peer_ctx = peer_ctx;
+  pending_msg->type = type;
+  GNUNET_CONTAINER_DLL_insert (peer_ctx->pending_messages_head,
+                               peer_ctx->pending_messages_tail,
+                               pending_msg);
+  return pending_msg;
+}
+
+
+/**
+ * @brief Remove a pending message from the respective DLL
+ *
+ * @param pending_msg the pending message to remove
+ * @param cancel cancel the pending message, too
+ */
+static void
+remove_pending_message (struct PendingMessage *pending_msg, int cancel)
+{
+  struct PeerContext *peer_ctx;
+
+  peer_ctx = pending_msg->peer_ctx;
+  GNUNET_assert (NULL != peer_ctx);
+  GNUNET_CONTAINER_DLL_remove (peer_ctx->pending_messages_head,
+                               peer_ctx->pending_messages_tail,
+                               pending_msg);
+  // TODO wait for the cadet implementation of message cancellation
+  //if (GNUNET_YES == cancel)
+  //{
+  //  GNUNET_MQ_send_cancel (pending_msg->ev);
+  //}
+  GNUNET_free (pending_msg);
+}
+
+
+/**
+ * @brief Check whether function of type #PeerOp was already scheduled
+ *
+ * The array with pending operations will probably never grow really big, so
+ * iterating over it should be ok.
+ *
+ * @param peer the peer to check
+ * @param peer_op the operation (#PeerOp) on the peer
+ *
+ * @return #GNUNET_YES if this operation is scheduled on that peer
+ *         #GNUNET_NO  otherwise
+ */
+static int
+check_operation_scheduled (const struct GNUNET_PeerIdentity *peer,
+                           const PeerOp peer_op)
+{
+  const struct PeerContext *peer_ctx;
+  unsigned int i;
+
+  peer_ctx = get_peer_ctx (peer);
+  for (i = 0; i < peer_ctx->num_pending_ops; i++)
+    if (peer_op == peer_ctx->pending_ops[i].op)
+      return GNUNET_YES;
+  return GNUNET_NO;
+}
+
+int
+Peers_remove_peer (const struct GNUNET_PeerIdentity *peer);
+
+/**
+ * Iterator over hash map entries. Deletes all contexts of peers.
+ *
+ * @param cls closure
+ * @param key current public key
+ * @param value value in the hash map
+ * @return #GNUNET_YES if we should continue to iterate,
+ *         #GNUNET_NO if not.
+ */
+static int
+peermap_clear_iterator (void *cls,
+                        const struct GNUNET_PeerIdentity *key,
+                        void *value)
+{
+  Peers_remove_peer (key);
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief This is called once a message is sent.
+ *
+ * Removes the pending message
+ *
+ * @param cls type of the message that was sent
+ */
+static void
+mq_notify_sent_cb (void *cls)
+{
+  struct PendingMessage *pending_msg = (struct PendingMessage *) cls;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "%s was sent.\n",
+      pending_msg->type);
+  /* Do not cancle message */
+  remove_pending_message (pending_msg, GNUNET_NO);
+}
+
+
+/**
+ * @brief Iterator function for #store_valid_peers.
+ *
+ * Implements #GNUNET_CONTAINER_PeerMapIterator.
+ * Writes single peer to disk.
+ *
+ * @param cls the file handle to write to.
+ * @param peer current peer
+ * @param value unused
+ *
+ * @return  #GNUNET_YES if we should continue to
+ *          iterate,
+ *          #GNUNET_NO if not.
+ */
+static int
+store_peer_presistently_iterator (void *cls,
+                                  const struct GNUNET_PeerIdentity *peer,
+                                  void *value)
+{
+  const struct GNUNET_DISK_FileHandle *fh = cls;
+  char peer_string[128];
+  int size;
+  ssize_t ret;
+
+  if (NULL == peer)
+  {
+    return GNUNET_YES;
+  }
+  size = GNUNET_snprintf (peer_string,
+                          sizeof (peer_string),
+                          "%s\n",
+                          GNUNET_i2s_full (peer));
+  GNUNET_assert (53 == size);
+  ret = GNUNET_DISK_file_write (fh,
+                                peer_string,
+                                size);
+  GNUNET_assert (size == ret);
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief Store the peers currently in #valid_peers to disk.
+ */
+static void
+store_valid_peers ()
+{
+  struct GNUNET_DISK_FileHandle *fh;
+  uint32_t number_written_peers;
+  int ret;
+
+  if (0 == strncmp ("DISABLE", filename_valid_peers, 7))
+  {
+    return;
+  }
+
+  ret = GNUNET_DISK_directory_create_for_file (filename_valid_peers);
+  if (GNUNET_SYSERR == ret)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Not able to create directory for file `%s'\n",
+        filename_valid_peers);
+    GNUNET_break (0);
+  }
+  else if (GNUNET_NO == ret)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Directory for file `%s' exists but is not writable for us\n",
+        filename_valid_peers);
+    GNUNET_break (0);
+  }
+  fh = GNUNET_DISK_file_open (filename_valid_peers,
+                              GNUNET_DISK_OPEN_WRITE |
+                                  GNUNET_DISK_OPEN_CREATE,
+                              GNUNET_DISK_PERM_USER_READ |
+                                  GNUNET_DISK_PERM_USER_WRITE);
+  if (NULL == fh)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Not able to write valid peers to file `%s'\n",
+        filename_valid_peers);
+    return;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "Writing %u valid peers to disk\n",
+      GNUNET_CONTAINER_multipeermap_size (valid_peers));
+  number_written_peers =
+    GNUNET_CONTAINER_multipeermap_iterate (valid_peers,
+                                           store_peer_presistently_iterator,
+                                           fh);
+  GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fh));
+  GNUNET_assert (number_written_peers ==
+      GNUNET_CONTAINER_multipeermap_size (valid_peers));
+}
+
+
+/**
+ * @brief Convert string representation of peer id to peer id.
+ *
+ * Counterpart to #GNUNET_i2s_full.
+ *
+ * @param string_repr The string representation of the peer id
+ *
+ * @return The peer id
+ */
+static const struct GNUNET_PeerIdentity *
+s2i_full (const char *string_repr)
+{
+  struct GNUNET_PeerIdentity *peer;
+  size_t len;
+  int ret;
+
+  peer = GNUNET_new (struct GNUNET_PeerIdentity);
+  len = strlen (string_repr);
+  if (52 > len)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Not able to convert string representation of PeerID to PeerID\n"
+        "Sting representation: %s (len %lu) - too short\n",
+        string_repr,
+        len);
+    GNUNET_break (0);
+  }
+  else if (52 < len)
+  {
+    len = 52;
+  }
+  ret = GNUNET_CRYPTO_eddsa_public_key_from_string (string_repr,
+                                                    len,
+                                                    &peer->public_key);
+  if (GNUNET_OK != ret)
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Not able to convert string representation of PeerID to PeerID\n"
+        "Sting representation: %s\n",
+        string_repr);
+    GNUNET_break (0);
+  }
+  return peer;
+}
+
+
+/**
+ * @brief Restore the peers on disk to #valid_peers.
+ */
+static void
+restore_valid_peers ()
+{
+  off_t file_size;
+  uint32_t num_peers;
+  struct GNUNET_DISK_FileHandle *fh;
+  char *buf;
+  ssize_t size_read;
+  char *iter_buf;
+  char *str_repr;
+  const struct GNUNET_PeerIdentity *peer;
+
+  if (0 == strncmp ("DISABLE", filename_valid_peers, 7))
+  {
+    return;
+  }
+
+  if (GNUNET_OK != GNUNET_DISK_file_test (filename_valid_peers))
+  {
+    return;
+  }
+  fh = GNUNET_DISK_file_open (filename_valid_peers,
+                              GNUNET_DISK_OPEN_READ,
+                              GNUNET_DISK_PERM_NONE);
+  GNUNET_assert (NULL != fh);
+  GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_handle_size (fh, &file_size));
+  num_peers = file_size / 53;
+  buf = GNUNET_malloc (file_size);
+  size_read = GNUNET_DISK_file_read (fh, buf, file_size);
+  GNUNET_assert (size_read == file_size);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "Restoring %" PRIu32 " peers from file `%s'\n",
+      num_peers,
+      filename_valid_peers);
+  for (iter_buf = buf; iter_buf < buf + file_size - 1; iter_buf += 53)
+  {
+    str_repr = GNUNET_strndup (iter_buf, 53);
+    peer = s2i_full (str_repr);
+    GNUNET_free (str_repr);
+    add_valid_peer (peer);
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+        "Restored valid peer %s from disk\n",
+        GNUNET_i2s_full (peer));
+  }
+  iter_buf = NULL;
+  GNUNET_free (buf);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "num_peers: %" PRIu32 ", _size (valid_peers): %u\n",
+      num_peers,
+      GNUNET_CONTAINER_multipeermap_size (valid_peers));
+  if (num_peers != GNUNET_CONTAINER_multipeermap_size (valid_peers))
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Number of restored peers does not match file size. Have probably duplicates.\n");
+  }
+  GNUNET_assert (GNUNET_OK == GNUNET_DISK_file_close (fh));
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "Restored %u valid peers from disk\n",
+      GNUNET_CONTAINER_multipeermap_size (valid_peers));
+}
+
+
+/**
+ * @brief Initialise storage of peers
+ *
+ * @param fn_valid_peers filename of the file used to store valid peer ids
+ * @param cadet_h cadet handle
+ * @param disconnect_handler Disconnect handler
+ * @param own_id own peer identity
+ */
+void
+Peers_initialise (char* fn_valid_peers,
+                  struct GNUNET_CADET_Handle *cadet_h,
+                  GNUNET_CADET_DisconnectEventHandler disconnect_handler,
+                  const struct GNUNET_PeerIdentity *own_id)
+{
+  filename_valid_peers = GNUNET_strdup (fn_valid_peers);
+  cadet_handle = cadet_h;
+  own_identity = *own_id;
+  peer_map = GNUNET_CONTAINER_multipeermap_create (4, GNUNET_NO);
+  valid_peers = GNUNET_CONTAINER_multipeermap_create (4, GNUNET_NO);
+  restore_valid_peers ();
+}
+
+
+/**
+ * @brief Delete storage of peers that was created with #Peers_initialise ()
+ */
+void
+Peers_terminate ()
+{
+  if (GNUNET_SYSERR ==
+      GNUNET_CONTAINER_multipeermap_iterate (peer_map,
+                                             peermap_clear_iterator,
+                                             NULL))
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+        "Iteration destroying peers was aborted.\n");
+  }
+  GNUNET_CONTAINER_multipeermap_destroy (peer_map);
+  store_valid_peers ();
+  GNUNET_free (filename_valid_peers);
+  GNUNET_CONTAINER_multipeermap_destroy (valid_peers);
+}
+
+
+/**
+ * Iterator over #valid_peers hash map entries.
+ *
+ * @param cls closure - unused
+ * @param peer current peer id
+ * @param value value in the hash map - unused
+ * @return #GNUNET_YES if we should continue to
+ *         iterate,
+ *         #GNUNET_NO if not.
+ */
+static int
+valid_peer_iterator (void *cls,
+                     const struct GNUNET_PeerIdentity *peer,
+                     void *value)
+{
+  struct PeersIteratorCls *it_cls = cls;
+
+  return it_cls->iterator (it_cls->cls,
+                           peer);
+}
+
+
+/**
+ * @brief Get all currently known, valid peer ids.
+ *
+ * @param it function to call on each peer id
+ * @param it_cls extra argument to @a it
+ * @return the number of key value pairs processed,
+ *         #GNUNET_SYSERR if it aborted iteration
+ */
+int
+Peers_get_valid_peers (PeersIterator iterator,
+                       void *it_cls)
+{
+  struct PeersIteratorCls *cls;
+  int ret;
+
+  cls = GNUNET_new (struct PeersIteratorCls);
+  cls->iterator = iterator;
+  cls->cls = it_cls;
+  ret = GNUNET_CONTAINER_multipeermap_iterate (valid_peers,
+                                               valid_peer_iterator,
+                                               cls);
+  GNUNET_free (cls);
+  return ret;
+}
+
+
+/**
+ * @brief Add peer to known peers.
+ *
+ * This function is called on new peer_ids from 'external' sources
+ * (client seed, cadet get_peers(), ...)
+ *
+ * @param peer the new #GNUNET_PeerIdentity
+ *
+ * @return #GNUNET_YES if peer was inserted
+ *         #GNUNET_NO  otherwise (if peer was already known or
+ *                     peer was #own_identity)
+ */
+int
+Peers_insert_peer (const struct GNUNET_PeerIdentity *peer)
+{
+  if ( (GNUNET_YES == Peers_check_peer_known (peer)) ||
+       (0 == GNUNET_CRYPTO_cmp_peer_identity (peer, &own_identity)) )
+  {
+    return GNUNET_NO; /* We already know this peer - nothing to do */
+  }
+  (void) create_peer_ctx (peer);
+  return GNUNET_YES;
+}
+
+int
+Peers_check_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags);
+
+/**
+ * @brief Try connecting to a peer to see whether it is online
+ *
+ * If not known yet, insert into known peers
+ *
+ * @param peer the peer whose liveliness is to be checked
+ * @return #GNUNET_YES if peer had to be inserted
+ *         #GNUNET_NO  otherwise (if peer was already known or
+ *                     peer was #own_identity)
+ */
+int
+Peers_issue_peer_liveliness_check (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+  int ret;
+
+  if (0 == GNUNET_CRYPTO_cmp_peer_identity (peer, &own_identity))
+  {
+    return GNUNET_NO;
+  }
+  ret = Peers_insert_peer (peer);
+  peer_ctx = get_peer_ctx (peer);
+  if (GNUNET_NO == Peers_check_peer_flag (peer, Peers_ONLINE))
+  {
+    check_peer_live (peer_ctx);
+  }
+  return ret;
+}
+
+
+/**
+ * @brief Check if peer is removable.
+ *
+ * Check if
+ *  - a recv channel exists
+ *  - there are pending messages
+ *  - there is no pending pull reply
+ *
+ * @param peer the peer in question
+ * @return #GNUNET_YES    if peer is removable
+ *         #GNUNET_NO     if peer is NOT removable
+ *         #GNUNET_SYSERR if peer is not known
+ */
+int
+Peers_check_removable (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == GNUNET_CONTAINER_multipeermap_contains (peer_map, peer))
+  {
+    return GNUNET_SYSERR;
+  }
+
+  peer_ctx = get_peer_ctx (peer);
+  if ( (NULL != peer_ctx->recv_channel) ||
+       (NULL != peer_ctx->pending_messages_head) ||
+       (GNUNET_NO == check_peer_flag_set (peer_ctx, Peers_PULL_REPLY_PENDING)) )
+  {
+    return GNUNET_NO;
+  }
+  return GNUNET_YES;
+}
+
+uint32_t *
+Peers_get_channel_flag (const struct GNUNET_PeerIdentity *peer,
+                        enum Peers_ChannelRole role);
+
+int
+Peers_check_channel_flag (uint32_t *channel_flags, enum Peers_ChannelFlags flags);
+
+/**
+ * @brief Remove peer
+ *
+ * @param peer the peer to clean
+ * @return #GNUNET_YES if peer was removed
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_remove_peer (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+  uint32_t *channel_flag;
+
+  if (GNUNET_NO == GNUNET_CONTAINER_multipeermap_contains (peer_map, peer))
+  {
+    return GNUNET_NO;
+  }
+
+  peer_ctx = get_peer_ctx (peer);
+  set_peer_flag (peer_ctx, Peers_TO_DESTROY);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Going to remove peer %s\n",
+       GNUNET_i2s (&peer_ctx->peer_id));
+  Peers_unset_peer_flag (peer, Peers_ONLINE);
+
+  GNUNET_array_grow (peer_ctx->pending_ops, peer_ctx->num_pending_ops, 0);
+  while (NULL != peer_ctx->pending_messages_head)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+        "Removing unsent %s\n",
+        peer_ctx->pending_messages_head->type);
+    /* Cancle pending message, too */
+    remove_pending_message (peer_ctx->pending_messages_head, GNUNET_YES);
+  }
+  /* If we are still waiting for notification whether this peer is live
+   * cancel the according task */
+  if (NULL != peer_ctx->liveliness_check_pending)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+         "Removing pending liveliness check for peer %s\n",
+         GNUNET_i2s (&peer_ctx->peer_id));
+    // TODO wait until cadet sets mq->cancel_impl
+    //GNUNET_MQ_send_cancel (peer_ctx->liveliness_check_pending->ev);
+    GNUNET_free (peer_ctx->liveliness_check_pending);
+    peer_ctx->liveliness_check_pending = NULL;
+  }
+  channel_flag = Peers_get_channel_flag (peer, Peers_CHANNEL_ROLE_SENDING);
+  if (NULL != peer_ctx->send_channel &&
+      GNUNET_YES != Peers_check_channel_flag (channel_flag, Peers_CHANNEL_DESTROING))
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+        "Destroying send channel\n");
+    GNUNET_CADET_channel_destroy (peer_ctx->send_channel);
+    peer_ctx->send_channel = NULL;
+  }
+  channel_flag = Peers_get_channel_flag (peer, Peers_CHANNEL_ROLE_RECEIVING);
+  if (NULL != peer_ctx->recv_channel &&
+      GNUNET_YES != Peers_check_channel_flag (channel_flag, Peers_CHANNEL_DESTROING))
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+        "Destroying recv channel\n");
+    GNUNET_CADET_channel_destroy (peer_ctx->recv_channel);
+    peer_ctx->recv_channel = NULL;
+  }
+
+  GNUNET_free (peer_ctx->send_channel_flags);
+  GNUNET_free (peer_ctx->recv_channel_flags);
+
+  if (GNUNET_YES != GNUNET_CONTAINER_multipeermap_remove_all (peer_map, &peer_ctx->peer_id))
+  {
+    LOG (GNUNET_ERROR_TYPE_WARNING, "removing peer from peer_map failed\n");
+  }
+  GNUNET_free (peer_ctx);
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief set flags on a given peer.
+ *
+ * @param peer the peer to set flags on
+ * @param flags the flags
+ */
+void
+Peers_set_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags)
+{
+  struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+  set_peer_flag (peer_ctx, flags);
+}
+
+
+/**
+ * @brief unset flags on a given peer.
+ *
+ * @param peer the peer to unset flags on
+ * @param flags the flags
+ */
+void
+Peers_unset_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags)
+{
+  struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+  unset_peer_flag (peer_ctx, flags);
+}
+
+
+/**
+ * @brief Check whether flags on a peer are set.
+ *
+ * @param peer the peer to check the flag of
+ * @param flags the flags to check
+ *
+ * @return #GNUNET_SYSERR if peer is not known
+ *         #GNUNET_YES    if all given flags are set
+ *         #GNUNET_NO     otherwise
+ */
+int
+Peers_check_peer_flag (const struct GNUNET_PeerIdentity *peer, enum Peers_PeerFlags flags)
+{
+  struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {
+    return GNUNET_SYSERR;
+  }
+  peer_ctx = get_peer_ctx (peer);
+  return check_peer_flag_set (peer_ctx, flags);
+}
+
+
+/**
+ * @brief set flags on a given channel.
+ *
+ * @param channel the channel to set flags on
+ * @param flags the flags
+ */
+void
+Peers_set_channel_flag (uint32_t *channel_flags, enum Peers_ChannelFlags flags)
+{
+  set_channel_flag (channel_flags, flags);
+}
+
+
+/**
+ * @brief unset flags on a given channel.
+ *
+ * @param channel the channel to unset flags on
+ * @param flags the flags
+ */
+void
+Peers_unset_channel_flag (uint32_t *channel_flags, enum Peers_ChannelFlags flags)
+{
+  unset_channel_flag (channel_flags, flags);
+}
+
+
+/**
+ * @brief Check whether flags on a channel are set.
+ *
+ * @param channel the channel to check the flag of
+ * @param flags the flags to check
+ *
+ * @return #GNUNET_YES if all given flags are set
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_check_channel_flag (uint32_t *channel_flags, enum Peers_ChannelFlags flags)
+{
+  return check_channel_flag_set (channel_flags, flags);
+}
+
+/**
+ * @brief Get the flags for the channel in @a role for @a peer.
+ *
+ * @param peer Peer to get the channel flags for.
+ * @param role Role of channel to get flags for
+ *
+ * @return The flags.
+ */
+uint32_t *
+Peers_get_channel_flag (const struct GNUNET_PeerIdentity *peer,
+                        enum Peers_ChannelRole role)
+{
+  const struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+  if (Peers_CHANNEL_ROLE_SENDING == role)
+  {
+    return peer_ctx->send_channel_flags;
+  }
+  else if (Peers_CHANNEL_ROLE_RECEIVING == role)
+  {
+    return peer_ctx->recv_channel_flags;
+  }
+  else
+  {
+    GNUNET_assert (0);
+  }
+}
+
+/**
+ * @brief Check whether we have information about the given peer.
+ *
+ * FIXME probably deprecated. Make this the new _online.
+ *
+ * @param peer peer in question
+ *
+ * @return #GNUNET_YES if peer is known
+ *         #GNUNET_NO  if peer is not knwon
+ */
+int
+Peers_check_peer_known (const struct GNUNET_PeerIdentity *peer)
+{
+  return GNUNET_CONTAINER_multipeermap_contains (peer_map, peer);
+}
+
+
+/**
+ * @brief Check whether @a peer is actually a peer.
+ *
+ * A valid peer is a peer that we know exists eg. we were connected to once.
+ *
+ * @param peer peer in question
+ *
+ * @return #GNUNET_YES if peer is valid
+ *         #GNUNET_NO  if peer is not valid
+ */
+int
+Peers_check_peer_valid (const struct GNUNET_PeerIdentity *peer)
+{
+  return GNUNET_CONTAINER_multipeermap_contains (valid_peers, peer);
+}
+
+
+/**
+ * @brief Indicate that we want to send to the other peer
+ *
+ * This establishes a sending channel
+ *
+ * @param peer the peer to establish channel to
+ */
+void
+Peers_indicate_sending_intention (const struct GNUNET_PeerIdentity *peer)
+{
+  GNUNET_assert (GNUNET_YES == Peers_check_peer_known (peer));
+  (void) get_channel (peer);
+}
+
+
+/**
+ * @brief Check whether other peer has the intention to send/opened channel
+ *        towars us
+ *
+ * @param peer the peer in question
+ *
+ * @return #GNUNET_YES if peer has the intention to send
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_check_peer_send_intention (const struct GNUNET_PeerIdentity *peer)
+{
+  const struct PeerContext *peer_ctx;
+
+  peer_ctx = get_peer_ctx (peer);
+  if (NULL != peer_ctx->recv_channel)
+  {
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+
+/**
+ * Handle the channel a peer opens to us.
+ *
+ * @param cls The closure
+ * @param channel The channel the peer wants to establish
+ * @param initiator The peer's peer ID
+ *
+ * @return initial channel context for the channel
+ *         (can be NULL -- that's not an error)
+ */
+void *
+Peers_handle_inbound_channel (void *cls,
+                              struct GNUNET_CADET_Channel *channel,
+                              const struct GNUNET_PeerIdentity *initiator)
+{
+  struct PeerContext *peer_ctx;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+      "New channel was established to us (Peer %s).\n",
+      GNUNET_i2s (initiator));
+  GNUNET_assert (NULL != channel); /* according to cadet API */
+  /* Make sure we 'know' about this peer */
+  peer_ctx = create_or_get_peer_ctx (initiator);
+  set_peer_live (peer_ctx);
+  /* We only accept one incoming channel per peer */
+  if (GNUNET_YES == Peers_check_peer_send_intention (initiator))
+  {
+    set_channel_flag (peer_ctx->recv_channel_flags,
+                      Peers_CHANNEL_ESTABLISHED_TWICE);
+    GNUNET_CADET_channel_destroy (channel);
+    /* return the channel context */
+    return &peer_ctx->peer_id;
+  }
+  peer_ctx->recv_channel = channel;
+  return &peer_ctx->peer_id;
+}
+
+
+/**
+ * @brief Check whether a sending channel towards the given peer exists
+ *
+ * @param peer the peer to check for
+ *
+ * @return #GNUNET_YES if a sending channel towards that peer exists
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_check_sending_channel_exists (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  { /* If no such peer exists, there is no channel */
+    return GNUNET_NO;
+  }
+  peer_ctx = get_peer_ctx (peer);
+  if (NULL == peer_ctx->send_channel)
+  {
+    return GNUNET_NO;
+  }
+  return GNUNET_YES;
+}
+
+
+/**
+ * @brief check whether the given channel is the sending channel of the given
+ *        peer
+ *
+ * @param peer the peer in question
+ * @param channel the channel to check for
+ * @param role either #Peers_CHANNEL_ROLE_SENDING, or
+ *                    #Peers_CHANNEL_ROLE_RECEIVING
+ *
+ * @return #GNUNET_YES if the given chennel is the sending channel of the peer
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_check_channel_role (const struct GNUNET_PeerIdentity *peer,
+                          const struct GNUNET_CADET_Channel *channel,
+                          enum Peers_ChannelRole role)
+{
+  const struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {
+    return GNUNET_NO;
+  }
+  peer_ctx = get_peer_ctx (peer);
+  if ( (Peers_CHANNEL_ROLE_SENDING == role) &&
+       (channel == peer_ctx->send_channel) )
+  {
+    return GNUNET_YES;
+  }
+  if ( (Peers_CHANNEL_ROLE_RECEIVING == role) &&
+       (channel == peer_ctx->recv_channel) )
+  {
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+
+/**
+ * @brief Destroy the send channel of a peer e.g. stop indicating a sending
+ *        intention to another peer
+ *
+ * If there is also no channel to receive messages from that peer, remove it
+ * from the peermap.
+ * TODO really?
+ *
+ * @peer the peer identity of the peer whose sending channel to destroy
+ * @return #GNUNET_YES if channel was destroyed
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_destroy_sending_channel (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {
+    return GNUNET_NO;
+  }
+  peer_ctx = get_peer_ctx (peer);
+  if (NULL != peer_ctx->send_channel)
+  {
+    set_channel_flag (peer_ctx->send_channel_flags, Peers_CHANNEL_CLEAN);
+    GNUNET_CADET_channel_destroy (peer_ctx->send_channel);
+    peer_ctx->send_channel = NULL;
+    (void) Peers_check_connected (peer);
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+/**
+ * This is called when a channel is destroyed.
+ *
+ * @param cls The closure
+ * @param channel The channel being closed
+ * @param channel_ctx The context associated with this channel
+ */
+void
+Peers_cleanup_destroyed_channel (void *cls,
+                                 const struct GNUNET_CADET_Channel *channel)
+{
+  struct GNUNET_PeerIdentity *peer = cls;
+  struct PeerContext *peer_ctx;
+
+  if (GNUNET_NO == Peers_check_peer_known (peer))
+  {/* We don't want to implicitly create a context that we're about to kill */
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "channel (%s) without associated context was destroyed\n",
+       GNUNET_i2s (peer));
+    return;
+  }
+  peer_ctx = get_peer_ctx (peer);
+
+  /* If our peer issued the destruction of the channel, the #Peers_TO_DESTROY
+   * flag will be set. In this case simply make sure that the channels are
+   * cleaned. */
+  /* FIXME This distinction seems to be redundant */
+  if (Peers_check_peer_flag (peer, Peers_TO_DESTROY))
+  {/* We initiatad the destruction of this particular peer */
+    if (channel == peer_ctx->send_channel)
+      peer_ctx->send_channel = NULL;
+    else if (channel == peer_ctx->recv_channel)
+      peer_ctx->recv_channel = NULL;
+
+    if (NULL != peer_ctx->send_channel)
+    {
+      GNUNET_CADET_channel_destroy (peer_ctx->send_channel);
+      peer_ctx->send_channel = NULL;
+    }
+    if (NULL != peer_ctx->recv_channel)
+    {
+      GNUNET_CADET_channel_destroy (peer_ctx->recv_channel);
+      peer_ctx->recv_channel = NULL;
+    }
+    /* Set the #Peers_ONLINE flag accordingly */
+    (void) Peers_check_connected (peer);
+    return;
+  }
+
+  else
+  { /* We did not initiate the destruction of this peer */
+    if (channel == peer_ctx->send_channel)
+    { /* Something (but us) killd the channel - clean up peer */
+      LOG (GNUNET_ERROR_TYPE_DEBUG,
+          "send channel (%s) was destroyed - cleaning up\n",
+          GNUNET_i2s (peer));
+      peer_ctx->send_channel = NULL;
+    }
+    else if (channel == peer_ctx->recv_channel)
+    { /* Other peer doesn't want to send us messages anymore */
+      LOG (GNUNET_ERROR_TYPE_DEBUG,
+           "Peer %s destroyed recv channel - cleaning up channel\n",
+           GNUNET_i2s (peer));
+      peer_ctx->recv_channel = NULL;
+    }
+    else
+    {
+      LOG (GNUNET_ERROR_TYPE_WARNING,
+           "unknown channel (%s) was destroyed\n",
+           GNUNET_i2s (peer));
+    }
+  }
+  (void) Peers_check_connected (peer);
+}
+
+/**
+ * @brief Send a message to another peer.
+ *
+ * Keeps track about pending messages so they can be properly removed when the
+ * peer is destroyed.
+ *
+ * @param peer receeiver of the message
+ * @param ev envelope of the message
+ * @param type type of the message
+ */
+void
+Peers_send_message (const struct GNUNET_PeerIdentity *peer,
+                    struct GNUNET_MQ_Envelope *ev,
+                    const char *type)
+{
+  struct PendingMessage *pending_msg;
+  struct GNUNET_MQ_Handle *mq;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Sending message to %s of type %s\n",
+              GNUNET_i2s (peer),
+              type);
+  pending_msg = insert_pending_message (peer, ev, type);
+  mq = get_mq (peer);
+  GNUNET_MQ_notify_sent (ev,
+                         mq_notify_sent_cb,
+                         pending_msg);
+  GNUNET_MQ_send (mq, ev);
+}
+
+/**
+ * @brief Schedule a operation on given peer
+ *
+ * Avoids scheduling an operation twice.
+ *
+ * @param peer the peer we want to schedule the operation for once it gets live
+ *
+ * @return #GNUNET_YES if the operation was scheduled
+ *         #GNUNET_NO  otherwise
+ */
+int
+Peers_schedule_operation (const struct GNUNET_PeerIdentity *peer,
+                          const PeerOp peer_op)
+{
+  struct PeerPendingOp pending_op;
+  struct PeerContext *peer_ctx;
+
+  if (0 == GNUNET_CRYPTO_cmp_peer_identity (peer, &own_identity))
+  {
+    return GNUNET_NO;
+  }
+  GNUNET_assert (GNUNET_YES == Peers_check_peer_known (peer));
+
+  //TODO if LIVE/ONLINE execute immediately
+
+  if (GNUNET_NO == check_operation_scheduled (peer, peer_op))
+  {
+    peer_ctx = get_peer_ctx (peer);
+    pending_op.op = peer_op;
+    pending_op.op_cls = NULL;
+    GNUNET_array_append (peer_ctx->pending_ops,
+                         peer_ctx->num_pending_ops,
+                         pending_op);
+    return GNUNET_YES;
+  }
+  return GNUNET_NO;
+}
+
+/**
+ * @brief Get the recv_channel of @a peer.
+ * Needed to correctly handle (call #GNUNET_CADET_receive_done()) incoming
+ * messages.
+ *
+ * @param peer The peer to get the recv_channel from.
+ *
+ * @return The recv_channel.
+ */
+struct GNUNET_CADET_Channel *
+Peers_get_recv_channel (const struct GNUNET_PeerIdentity *peer)
+{
+  struct PeerContext *peer_ctx;
+
+  GNUNET_assert (GNUNET_YES == Peers_check_peer_known (peer));
+  peer_ctx = get_peer_ctx (peer);
+  return peer_ctx->recv_channel;
+}
+/***********************************************************************
+ * /Old gnunet-service-rps_peers.c
+***********************************************************************/
+
+
 /***********************************************************************
  * Housekeeping with clients
 ***********************************************************************/
@@ -847,6 +2568,7 @@ cleanup_destroyed_channel (void *cls,
 {
   struct GNUNET_PeerIdentity *peer = cls;
   uint32_t *channel_flag;
+  struct PeerContext *peer_ctx;
 
   if (GNUNET_NO == Peers_check_peer_known (peer))
   { /* We don't know a context to that peer */
@@ -856,6 +2578,15 @@ cleanup_destroyed_channel (void *cls,
     return;
   }
 
+  peer_ctx = get_peer_ctx (peer);
+  if (GNUNET_YES == Peers_check_channel_role (peer, channel, Peers_CHANNEL_ROLE_RECEIVING))
+  {
+    set_channel_flag (peer_ctx->recv_channel_flags, Peers_CHANNEL_DESTROING);
+  } else if (GNUNET_YES == Peers_check_channel_role (peer, channel, Peers_CHANNEL_ROLE_SENDING))
+  {
+    set_channel_flag (peer_ctx->send_channel_flags, Peers_CHANNEL_DESTROING);
+  }
+
   if (GNUNET_YES == Peers_check_peer_flag (peer, Peers_TO_DESTROY))
   { /* We are in the middle of removing that peer from our knowledge. In this
        case simply make sure that the channels are cleaned. */
@@ -1121,7 +2852,6 @@ handle_client_request_cancel (void *cls,
           (rep_cls->id != ntohl (msg->id)) )
     rep_cls = rep_cls->next;
   GNUNET_assert (rep_cls->id == ntohl (msg->id));
-  RPS_sampler_request_cancel (rep_cls->req_handle);
   destroy_reply_cls (rep_cls);
   GNUNET_SERVICE_client_continue (cli_ctx->client);
 }
@@ -1239,24 +2969,24 @@ handle_peer_push (void *cls,
        (3 == mal_type) )
   { /* Try to maximise representation */
     tmp_att_peer = GNUNET_new (struct AttackedPeer);
-    GNUNET_memcpy (&tmp_att_peer->peer_id, peer, sizeof (struct GNUNET_PeerIdentity));
+    tmp_att_peer->peer_id = *peer;
     if (NULL == att_peer_set)
       att_peer_set = GNUNET_CONTAINER_multipeermap_create (1, GNUNET_NO);
-    if (GNUNET_NO == GNUNET_CONTAINER_multipeermap_contains (att_peer_set,
-                                                             peer))
+    if (GNUNET_NO ==
+        GNUNET_CONTAINER_multipeermap_contains (att_peer_set,
+                                                peer))
     {
       GNUNET_CONTAINER_DLL_insert (att_peers_head,
                                    att_peers_tail,
                                    tmp_att_peer);
       add_peer_array_to_set (peer, 1, att_peer_set);
     }
-    GNUNET_CADET_receive_done (Peers_get_recv_channel (peer));
   }
 
 
   else if (2 == mal_type)
-  { /* We attack one single well-known peer - simply ignore */
-    GNUNET_CADET_receive_done (Peers_get_recv_channel (peer));
+  {
+    /* We attack one single well-known peer - simply ignore */
   }
   #endif /* ENABLE_MALICIOUS */
 
@@ -1289,7 +3019,6 @@ handle_peer_pull_request (void *cls,
       || 3 == mal_type)
   { /* Try to maximise representation */
     send_pull_reply (peer, mal_peers, num_mal_peers);
-    GNUNET_CADET_receive_done (Peers_get_recv_channel (peer));
   }
 
   else if (2 == mal_type)
@@ -1298,7 +3027,6 @@ handle_peer_pull_request (void *cls,
     {
       send_pull_reply (peer, mal_peers, num_mal_peers);
     }
-    GNUNET_CADET_receive_done (Peers_get_recv_channel (peer));
   }
   #endif /* ENABLE_MALICIOUS */
 
@@ -1360,7 +3088,7 @@ static void
 handle_peer_pull_reply (void *cls,
                         const struct GNUNET_RPS_P2P_PullReplyMessage *msg)
 {
-  struct GNUNET_PeerIdentity *peers;
+  const struct GNUNET_PeerIdentity *peers;
   struct GNUNET_PeerIdentity *sender = cls;
   uint32_t i;
 #ifdef ENABLE_MALICIOUS
@@ -1373,12 +3101,11 @@ handle_peer_pull_reply (void *cls,
   // We shouldn't even receive pull replies as we're not sending
   if (2 == mal_type)
   {
-    GNUNET_CADET_receive_done (Peers_get_recv_channel (sender));
   }
   #endif /* ENABLE_MALICIOUS */
 
   /* Do actual logic */
-  peers = (struct GNUNET_PeerIdentity *) &msg[1];
+  peers = (const struct GNUNET_PeerIdentity *) &msg[1];
 
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "PULL REPLY received, got following %u peers:\n",
@@ -2132,7 +3859,6 @@ shutdown_task (void *cls)
                                    reply_cls);
       GNUNET_free (reply_cls);
     }
-    GNUNET_MQ_destroy (client_ctx->mq);
     GNUNET_CONTAINER_DLL_remove (cli_ctx_head, cli_ctx_tail, client_ctx);
     GNUNET_free (client_ctx);
   }
@@ -2150,6 +3876,7 @@ shutdown_task (void *cls)
   GNUNET_NSE_disconnect (nse);
   RPS_sampler_destroy (prot_sampler);
   RPS_sampler_destroy (client_sampler);
+  GNUNET_CADET_close_port (cadet_port);
   GNUNET_CADET_disconnect (cadet_handle);
   View_destroy ();
   CustomPeerMap_destroy (push_map);
@@ -2240,26 +3967,6 @@ run (void *cls,
      const struct GNUNET_CONFIGURATION_Handle *c,
      struct GNUNET_SERVICE_Handle *service)
 {
-  struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
-    GNUNET_MQ_hd_fixed_size (peer_check,
-                             GNUNET_MESSAGE_TYPE_RPS_PP_CHECK_LIVE,
-                             struct GNUNET_MessageHeader,
-                             NULL),
-    GNUNET_MQ_hd_fixed_size (peer_push,
-                             GNUNET_MESSAGE_TYPE_RPS_PP_PUSH,
-                             struct GNUNET_MessageHeader,
-                             NULL),
-    GNUNET_MQ_hd_fixed_size (peer_pull_request,
-                             GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REQUEST,
-                             struct GNUNET_MessageHeader,
-                             NULL),
-    GNUNET_MQ_hd_var_size (peer_pull_reply,
-                           GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REPLY,
-                           struct GNUNET_RPS_P2P_PullReplyMessage,
-                           NULL),
-    GNUNET_MQ_handler_end ()
-  };
-
   int size;
   int out_size;
   char* fn_valid_peers;
@@ -2349,6 +4056,27 @@ run (void *cls,
 
 
   /* Initialise cadet */
+  /* There exists a copy-paste-clone in get_channel() */
+  struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
+    GNUNET_MQ_hd_fixed_size (peer_check,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_CHECK_LIVE,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_fixed_size (peer_push,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_PUSH,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_fixed_size (peer_pull_request,
+                             GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REQUEST,
+                             struct GNUNET_MessageHeader,
+                             NULL),
+    GNUNET_MQ_hd_var_size (peer_pull_reply,
+                           GNUNET_MESSAGE_TYPE_RPS_PP_PULL_REPLY,
+                           struct GNUNET_RPS_P2P_PullReplyMessage,
+                           NULL),
+    GNUNET_MQ_handler_end ()
+  };
+
   cadet_handle = GNUNET_CADET_connect (cfg);
   GNUNET_assert (NULL != cadet_handle);
   GNUNET_CRYPTO_hash (GNUNET_APPLICATION_PORT_RPS,
@@ -2365,7 +4093,7 @@ run (void *cls,
 
   peerinfo_handle = GNUNET_PEERINFO_connect (cfg);
   Peers_initialise (fn_valid_peers, cadet_handle, cleanup_destroyed_channel,
-                    cadet_handlers, &own_identity);
+                    &own_identity);
   GNUNET_free (fn_valid_peers);
 
   /* Initialise sampler */