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diff --git a/src/cadet/gnunet-service-cadet_tunnel.h b/src/cadet/gnunet-service-cadet_tunnel.h
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+++ b/src/cadet/gnunet-service-cadet_tunnel.h
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+/*
+     This file is part of GNUnet.
+     (C) 2013 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 cadet/gnunet-service-cadet_tunnel.h
+ * @brief cadet service; dealing with tunnels and crypto
+ * @author Bartlomiej Polot
+ *
+ * All functions in this file should use the prefix GMT (Gnunet Cadet Tunnel)
+ */
+
+#ifndef GNUNET_SERVICE_CADET_TUNNEL_H
+#define GNUNET_SERVICE_CADET_TUNNEL_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#if 0                           /* keep Emacsens' auto-indent happy */
+}
+#endif
+#endif
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+
+/**
+ * All the connectivity states a tunnel can be in.
+ */
+enum CadetTunnel3CState
+{
+    /**
+     * Uninitialized status, should never appear in operation.
+     */
+  CADET_TUNNEL3_NEW,
+
+    /**
+     * Path to the peer not known yet.
+     */
+  CADET_TUNNEL3_SEARCHING,
+
+    /**
+     * Request sent, not yet answered.
+     */
+  CADET_TUNNEL3_WAITING,
+
+    /**
+     * Peer connected and ready to accept data.
+     */
+  CADET_TUNNEL3_READY,
+
+  /**
+   * Tunnel being shut down, don't try to keep it alive.
+   */
+  CADET_TUNNEL3_SHUTDOWN
+};
+
+
+/**
+ * All the encryption states a tunnel can be in.
+ */
+enum CadetTunnel3EState
+{
+  /**
+   * Uninitialized status, should never appear in operation.
+   */
+  CADET_TUNNEL3_KEY_UNINITIALIZED,
+
+  /**
+   * Ephemeral key sent, waiting for peer's key.
+   */
+  CADET_TUNNEL3_KEY_SENT,
+
+  /**
+   * New ephemeral key and ping sent, waiting for pong.
+   * This means that we DO have the peer's ephemeral key, otherwise the
+   * state would be KEY_SENT.
+   */
+  CADET_TUNNEL3_KEY_PING,
+
+  /**
+   * Handshake completed: session key available.
+   */
+  CADET_TUNNEL3_KEY_OK,
+};
+
+/**
+ * Struct containing all information regarding a given peer
+ */
+struct CadetTunnel3;
+
+
+#include "gnunet-service-cadet_channel.h"
+#include "gnunet-service-cadet_connection.h"
+#include "gnunet-service-cadet_peer.h"
+
+/**
+ * Handle for messages queued but not yet sent.
+ */
+struct CadetTunnel3Queue;
+
+/**
+ * Callback called when a queued message is sent.
+ *
+ * @param cls Closure.
+ * @param t Tunnel this message was on.
+ * @param type Type of message sent.
+ * @param size Size of the message.
+ */
+typedef void (*GMT_sent) (void *cls,
+                          struct CadetTunnel3 *t,
+                          struct CadetTunnel3Queue *q,
+                          uint16_t type, size_t size);
+
+typedef void (*GMT_conn_iter) (void *cls, struct CadetConnection *c);
+typedef void (*GMT_chan_iter) (void *cls, struct CadetChannel *ch);
+
+
+/******************************************************************************/
+/********************************    API    ***********************************/
+/******************************************************************************/
+
+/**
+ * Initialize tunnel subsystem.
+ *
+ * @param c Configuration handle.
+ * @param key ECC private key, to derive all other keys and do crypto.
+ */
+void
+GMT_init (const struct GNUNET_CONFIGURATION_Handle *c,
+          const struct GNUNET_CRYPTO_EddsaPrivateKey *key);
+
+/**
+ * Shut down the tunnel subsystem.
+ */
+void
+GMT_shutdown (void);
+
+/**
+ * Create a tunnel.
+ *
+ * @param destination Peer this tunnel is towards.
+ */
+struct CadetTunnel3 *
+GMT_new (struct CadetPeer *destination);
+
+/**
+ * Tunnel is empty: destroy it.
+ *
+ * Notifies all connections about the destruction.
+ *
+ * @param t Tunnel to destroy.
+ */
+void
+GMT_destroy_empty (struct CadetTunnel3 *t);
+
+/**
+ * Destroy tunnel if empty (no more channels).
+ *
+ * @param t Tunnel to destroy if empty.
+ */
+void
+GMT_destroy_if_empty (struct CadetTunnel3 *t);
+
+/**
+ * Destroy the tunnel.
+ *
+ * This function does not generate any warning traffic to clients or peers.
+ *
+ * Tasks:
+ * Cancel messages belonging to this tunnel queued to neighbors.
+ * Free any allocated resources linked to the tunnel.
+ *
+ * @param t The tunnel to destroy.
+ */
+void
+GMT_destroy (struct CadetTunnel3 *t);
+
+
+/**
+ * Change the tunnel's connection state.
+ *
+ * @param t Tunnel whose connection state to change.
+ * @param cstate New connection state.
+ */
+void
+GMT_change_cstate (struct CadetTunnel3* t, enum CadetTunnel3CState cstate);
+
+
+/**
+ * Change the tunnel encryption state.
+ *
+ * @param t Tunnel whose encryption state to change.
+ * @param state New encryption state.
+ */
+void
+GMT_change_estate (struct CadetTunnel3* t, enum CadetTunnel3EState state);
+
+/**
+ * Add a connection to a tunnel.
+ *
+ * @param t Tunnel.
+ * @param c Connection.
+ */
+void
+GMT_add_connection (struct CadetTunnel3 *t, struct CadetConnection *c);
+
+/**
+ * Mark a path as no longer valid for this tunnel: has been tried and failed.
+ *
+ * @param t Tunnel to update.
+ * @param path Invalid path to remove. Is destroyed after removal.
+ */
+void
+GMT_remove_path (struct CadetTunnel3 *t, struct CadetPeerPath *path);
+
+/**
+ * Remove a connection from a tunnel.
+ *
+ * @param t Tunnel.
+ * @param c Connection.
+ */
+void
+GMT_remove_connection (struct CadetTunnel3 *t, struct CadetConnection *c);
+
+/**
+ * Add a channel to a tunnel.
+ *
+ * @param t Tunnel.
+ * @param ch Channel.
+ */
+void
+GMT_add_channel (struct CadetTunnel3 *t, struct CadetChannel *ch);
+
+/**
+ * Remove a channel from a tunnel.
+ *
+ * @param t Tunnel.
+ * @param ch Channel.
+ */
+void
+GMT_remove_channel (struct CadetTunnel3 *t, struct CadetChannel *ch);
+
+/**
+ * Search for a channel by global ID.
+ *
+ * @param t Tunnel containing the channel.
+ * @param chid Public channel number.
+ *
+ * @return channel handler, NULL if doesn't exist
+ */
+struct CadetChannel *
+GMT_get_channel (struct CadetTunnel3 *t, CADET_ChannelNumber chid);
+
+/**
+ * Decrypt and demultiplex by message type. Call appropriate handler
+ * for a message
+ * towards a channel of a local tunnel.
+ *
+ * @param t Tunnel this message came on.
+ * @param msg Message header.
+ */
+void
+GMT_handle_encrypted (struct CadetTunnel3 *t,
+                      const struct GNUNET_CADET_Encrypted *msg);
+
+/**
+ * Demultiplex an encapsulated KX message by message type.
+ *
+ * @param t Tunnel on which the message came.
+ * @param message KX message itself.
+ */
+void
+GMT_handle_kx (struct CadetTunnel3 *t,
+               const struct GNUNET_MessageHeader *message);
+
+/**
+ * @brief Use the given path for the tunnel.
+ * Update the next and prev hops (and RCs).
+ * (Re)start the path refresh in case the tunnel is locally owned.
+ *
+ * @param t Tunnel to update.
+ * @param p Path to use.
+ *
+ * @return Connection created.
+ */
+struct CadetConnection *
+GMT_use_path (struct CadetTunnel3 *t, struct CadetPeerPath *p);
+
+/**
+ * Count established (ready) connections of a tunnel.
+ *
+ * @param t Tunnel on which to count.
+ *
+ * @return Number of connections.
+ */
+unsigned int
+GMT_count_connections (struct CadetTunnel3 *t);
+
+/**
+ * Count channels of a tunnel.
+ *
+ * @param t Tunnel on which to count.
+ *
+ * @return Number of channels.
+ */
+unsigned int
+GMT_count_channels (struct CadetTunnel3 *t);
+
+/**
+ * Get the connectivity state of a tunnel.
+ *
+ * @param t Tunnel.
+ *
+ * @return Tunnel's connectivity state.
+ */
+enum CadetTunnel3CState
+GMT_get_cstate (struct CadetTunnel3 *t);
+
+/**
+ * Get the encryption state of a tunnel.
+ *
+ * @param t Tunnel.
+ *
+ * @return Tunnel's encryption state.
+ */
+enum CadetTunnel3EState
+GMT_get_estate (struct CadetTunnel3 *t);
+
+/**
+ * Get the maximum buffer space for a tunnel towards a local client.
+ *
+ * @param t Tunnel.
+ *
+ * @return Biggest buffer space offered by any channel in the tunnel.
+ */
+unsigned int
+GMT_get_channels_buffer (struct CadetTunnel3 *t);
+
+/**
+ * Get the total buffer space for a tunnel for P2P traffic.
+ *
+ * @param t Tunnel.
+ *
+ * @return Buffer space offered by all connections in the tunnel.
+ */
+unsigned int
+GMT_get_connections_buffer (struct CadetTunnel3 *t);
+
+/**
+ * Get the tunnel's destination.
+ *
+ * @param t Tunnel.
+ *
+ * @return ID of the destination peer.
+ */
+const struct GNUNET_PeerIdentity *
+GMT_get_destination (struct CadetTunnel3 *t);
+
+/**
+ * Get the tunnel's next free Channel ID.
+ *
+ * @param t Tunnel.
+ *
+ * @return ID of a channel free to use.
+ */
+CADET_ChannelNumber
+GMT_get_next_chid (struct CadetTunnel3 *t);
+
+/**
+ * Send ACK on one or more channels due to buffer in connections.
+ *
+ * @param t Channel which has some free buffer space.
+ */
+void
+GMT_unchoke_channels (struct CadetTunnel3 *t);
+
+/**
+ * Send ACK on one or more connections due to buffer space to the client.
+ *
+ * Iterates all connections of the tunnel and sends ACKs appropriately.
+ *
+ * @param t Tunnel which has some free buffer space.
+ */
+void
+GMT_send_connection_acks (struct CadetTunnel3 *t);
+
+/**
+ * Cancel a previously sent message while it's in the queue.
+ *
+ * ONLY can be called before the continuation given to the send function
+ * is called. Once the continuation is called, the message is no longer in the
+ * queue.
+ *
+ * @param q Handle to the queue.
+ */
+void
+GMT_cancel (struct CadetTunnel3Queue *q);
+
+/**
+ * Sends an already built message on a tunnel, encrypting it and
+ * choosing the best connection.
+ *
+ * @param message Message to send. Function modifies it.
+ * @param t Tunnel on which this message is transmitted.
+ * @param c Connection to use (autoselect if NULL).
+ * @param force Force the tunnel to take the message (buffer overfill).
+ * @param cont Continuation to call once message is really sent.
+ * @param cont_cls Closure for @c cont.
+ *
+ * @return Handle to cancel message. NULL if @c cont is NULL.
+ */
+struct CadetTunnel3Queue *
+GMT_send_prebuilt_message (const struct GNUNET_MessageHeader *message,
+                           struct CadetTunnel3 *t, struct CadetConnection *c,
+                           int force, GMT_sent cont, void *cont_cls);
+
+/**
+ * Is the tunnel directed towards the local peer?
+ *
+ * @param t Tunnel.
+ *
+ * @return #GNUNET_YES if it is loopback.
+ */
+int
+GMT_is_loopback (const struct CadetTunnel3 *t);
+
+/**
+ * Is the tunnel using this path already?
+ *
+ * @param t Tunnel.
+ * @param p Path.
+ *
+ * @return #GNUNET_YES a connection uses this path.
+ */
+int
+GMT_is_path_used (const struct CadetTunnel3 *t, const struct CadetPeerPath *p);
+
+/**
+ * Get a cost of a path for a tunnel considering existing connections.
+ *
+ * @param t Tunnel.
+ * @param path Candidate path.
+ *
+ * @return Cost of the path (path length + number of overlapping nodes)
+ */
+unsigned int
+GMT_get_path_cost (const struct CadetTunnel3 *t,
+                   const struct CadetPeerPath *path);
+
+/**
+ * Get the static string for the peer this tunnel is directed.
+ *
+ * @param t Tunnel.
+ *
+ * @return Static string the destination peer's ID.
+ */
+const char *
+GMT_2s (const struct CadetTunnel3 *t);
+
+/**
+ * Log all possible info about the tunnel state.
+ *
+ * @param t Tunnel to debug.
+ */
+void
+GMT_debug (const struct CadetTunnel3 *t);
+
+/**
+ * Iterate all tunnels.
+ *
+ * @param iter Iterator.
+ * @param cls Closure for @c iter.
+ */
+void
+GMT_iterate_all (GNUNET_CONTAINER_PeerMapIterator iter, void *cls);
+
+/**
+ * Count all tunnels.
+ *
+ * @return Number of tunnels to remote peers kept by this peer.
+ */
+unsigned int
+GMT_count_all (void);
+
+/**
+ * Iterate all connections of a tunnel.
+ *
+ * @param t Tunnel whose connections to iterate.
+ * @param iter Iterator.
+ * @param cls Closure for @c iter.
+ */
+void
+GMT_iterate_connections (struct CadetTunnel3 *t, GMT_conn_iter iter, void *cls);
+
+/**
+ * Iterate all channels of a tunnel.
+ *
+ * @param t Tunnel whose channels to iterate.
+ * @param iter Iterator.
+ * @param cls Closure for @c iter.
+ */
+void
+GMT_iterate_channels (struct CadetTunnel3 *t, GMT_chan_iter iter, void *cls);
+
+#if 0                           /* keep Emacsens' auto-indent happy */
+{
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+/* ifndef GNUNET_CADET_SERVICE_TUNNEL_H */
+#endif
+/* end of gnunet-cadet-service_tunnel.h */