gnunet-android

gnunet_cadet_service.h (17653B)

---

 /*
      This file is part of GNUnet.
      Copyright (C) 2009-2017 GNUnet e.V.
 
      GNUnet is free software: you can redistribute it and/or modify it
      under the terms of the GNU Affero General Public License as published
      by the Free Software Foundation, either version 3 of the License,
      or (at your option) any later version.
 
      GNUnet is distributed in the hope that it will be useful, but
      WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      Affero General Public License for more details.
 
      You should have received a copy of the GNU Affero General Public License
      along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
      SPDX-License-Identifier: AGPL3.0-or-later
  */
 /**
  * @addtogroup Backbone
  * @{
  *
  * @author Christian Grothoff
  * @author Bart Polot
  *
  * @file
  * CADET service; establish channels to distant peers
  *
  * @defgroup cadet  CADET service
  * Confidential Ad-hoc Decentralized End-to-End Transport
  *
  * @see [Documentation](https://gnunet.org/cadet-subsystem)
  * @see [Paper](https://gnunet.org/cadet)
  *
  * @{
  */
 #ifndef GNUNET_CADET_SERVICE_H
 #define GNUNET_CADET_SERVICE_H
 
 #ifdef __cplusplus
 extern "C" {
 #if 0 /* keep Emacsens' auto-indent happy */
 }
 #endif
 #endif
 
 
 #include "gnunet_util_lib.h"
 
 /**
  * Version number of GNUnet-cadet API.
  */
 #define GNUNET_CADET_VERSION 0x00000005
 
 
 /**
  * Opaque handle to the service.
  */
 struct GNUNET_CADET_Handle;
 
 /**
  * Opaque handle to a channel.
  */
 struct GNUNET_CADET_Channel;
 
 /**
  * Opaque handle to a port.
  */
 struct GNUNET_CADET_Port;
 
 
 /**
  * Hash uniquely identifying a connection below a tunnel.
  */
 struct GNUNET_CADET_ConnectionTunnelIdentifier
 {
   struct GNUNET_ShortHashCode connection_of_tunnel;
 };
 
 
 /**
  * Number identifying a CADET channel within a tunnel.
  */
 struct GNUNET_CADET_ChannelTunnelNumber
 {
   /**
    * Which number does this channel have that uniquely identifies
    * it within its tunnel, in network byte order.
    *
    * Given two peers, both may initiate channels over the same tunnel.
    * The @e cn must be greater or equal to 0x80000000 (high-bit set)
    * for tunnels initiated with the peer that has the larger peer
    * identity as compared using #GNUNET_memcmp().
    */
   uint32_t cn GNUNET_PACKED;
 };
 
 /**
  * Method called whenever a peer connects to a port in MQ-based CADET.
  *
  * @param cls Closure from #GNUNET_CADET_open_port.
  * @param channel New handle to the channel.
  * @param source Peer that started this channel.
  * @return Closure for the incoming @a channel. It's given to:
  *         - The #GNUNET_CADET_DisconnectEventHandler (given to
  *           #GNUNET_CADET_open_port) when the channel dies.
  *         - Each the #GNUNET_MQ_MessageCallback handlers for each message
  *           received on the @a channel.
  */
 typedef void *(*GNUNET_CADET_ConnectEventHandler) (
   void *cls,
   struct GNUNET_CADET_Channel *channel,
   const struct GNUNET_PeerIdentity *source);
 
 
 /**
  * Function called whenever an MQ-channel is destroyed, unless the destruction
  * was requested by #GNUNET_CADET_channel_destroy.
  * It must NOT call #GNUNET_CADET_channel_destroy on the channel.
  *
  * It should clean up any associated state, including cancelling any pending
  * transmission on this channel.
  *
  * @param cls Channel closure.
  * @param channel Connection to the other end (henceforth invalid).
  */
 typedef void (*GNUNET_CADET_DisconnectEventHandler) (
   void *cls,
   const struct GNUNET_CADET_Channel *channel);
 
 
 /**
  * Function called whenever an MQ-channel's transmission window size changes.
  *
  * The first callback in an outgoing channel will be with a non-zero value
  * and will mean the channel is connected to the destination.
  *
  * For an incoming channel it will be called immediately after the
  * #GNUNET_CADET_ConnectEventHandler, also with a non-zero value.
  *
  * @param cls Channel closure.
  * @param channel Connection to the other end --- FIXME: drop?
  * @param window_size New window size. If the is more messages than buffer size
  *                    this value will be negative. -- FIXME: make unsigned, we never call negative?
  */
 typedef void (*GNUNET_CADET_WindowSizeEventHandler) (
   void *cls,
   const struct GNUNET_CADET_Channel *channel,
   int window_size);
 
 
 /**
  * Connect to the MQ-based cadet service.
  *
  * @param cfg Configuration to use.
  * @return Handle to the cadet service NULL on error.
  */
 struct GNUNET_CADET_Handle *
 GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg);
 
 
 /**
  * Disconnect from the cadet service. All channels will be destroyed. All channel
  * disconnect callbacks will be called on any still connected peers, notifying
  * about their disconnection. The registered inbound channel cleaner will be
  * called should any inbound channels still exist.
  *
  * @param handle connection to cadet to disconnect
  */
 void
 GNUNET_CADET_disconnect (struct GNUNET_CADET_Handle *handle);
 
 
 /**
  * Open a port to receive incoming MQ-based channels.
  *
  * @param h CADET handle.
  * @param port Hash identifying the port.
  * @param connects Function called when an incoming channel is connected.
  * @param connects_cls Closure for the @a connects handler.
  * @param window_changes Function called when the transmit window size changes.
  *                       Can be NULL.
  * @param disconnects Function called when a channel is disconnected.
  * @param handlers Callbacks for messages we care about, NULL-terminated.
  * @return Port handle, NULL if port is in use
  */
 struct GNUNET_CADET_Port *
 GNUNET_CADET_open_port (struct GNUNET_CADET_Handle *h,
                         const struct GNUNET_HashCode *port,
                         GNUNET_CADET_ConnectEventHandler connects,
                         void *connects_cls,
                         GNUNET_CADET_WindowSizeEventHandler window_changes,
                         GNUNET_CADET_DisconnectEventHandler disconnects,
                         const struct GNUNET_MQ_MessageHandler *handlers);
 
 
 /**
  * Close a port opened with @a GNUNET_CADET_open_port.
  * The @a new_channel callback will no longer be called.
  *
  * @param p Port handle.
  */
 void
 GNUNET_CADET_close_port (struct GNUNET_CADET_Port *p);
 
 
 /**
  * Create a new channel towards a remote peer.
  *
  * If the destination peer closes the channel after accepting it,
  * @a disconnects will be called for this channel (unless
  * #GNUNET_CADET_channel_destroy() was called on this end first).
  *
  * @param h CADET handle.
  * @param channel_cls Closure for the channel. It's given to:
  *                    - The management handler @a window_changes.
  *                    - The disconnect handler @a disconnects
  *                    - Each message type callback in @a handlers
  * @param destination Peer identity the channel should go to.
  * @param port Identification of the destination port.
  * @param window_changes Function called when the transmit window size changes.
  *                       Can be NULL if this data is of no interest.
  * @param disconnects Function called when the channel is disconnected.
  * @param handlers Callbacks for messages we care about, NULL-terminated.
  * @return Handle to the channel.
  */
 struct GNUNET_CADET_Channel *
 GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h,
                              void *channel_cls,
                              const struct GNUNET_PeerIdentity *destination,
                              const struct GNUNET_HashCode *port,
                              GNUNET_CADET_WindowSizeEventHandler window_changes,
                              GNUNET_CADET_DisconnectEventHandler disconnects,
                              const struct GNUNET_MQ_MessageHandler *handlers);
 
 
 /**
  * Destroy an existing channel.
  *
  * The existing end callback for the channel will NOT be called.
  * Any pending outgoing messages will be sent but no incoming messages will be
  * accepted and no data callbacks will be called.
  *
  * @param channel Channel handle, becomes invalid after this call.
  */
 void
 GNUNET_CADET_channel_destroy (struct GNUNET_CADET_Channel *channel);
 
 
 /**
  * Obtain the message queue for a connected channel.
  *
  * @param channel The channel handle from which to get the MQ.
  * @return The message queue of the channel.
  */
 struct GNUNET_MQ_Handle *
 GNUNET_CADET_get_mq (const struct GNUNET_CADET_Channel *channel);
 
 
 /**
  * Indicate readiness to receive the next message on a channel.
  *
  * Should only be called once per handler called.
  *
  * @param channel Channel that will be allowed to call another handler.
  */
 void
 GNUNET_CADET_receive_done (struct GNUNET_CADET_Channel *channel);
 
 /**
  * Transitional function to convert an unsigned int port to a hash value.
  * WARNING: local static value returned, NOT reentrant!
  * WARNING: do not use this function for new code!
  *
  * @param port Numerical port (unsigned int format).
  *
  * @return A GNUNET_HashCode usable for the new CADET API.
  */
 const struct GNUNET_HashCode *
 GC_u2h (uint32_t port);
 
 enum GNUNET_CADET_ChannelInfoOption
 {
   /**
    * Who is the peer at the other end of the channel.
    * Only for use in @c GNUNET_CADET_channel_get_info
    * struct GNUNET_PeerIdentity *peer
    */
   GNUNET_CADET_OPTION_PEER = 0x0
 };
 
 /**
  * Union to retrieve info about a channel.
  */
 union GNUNET_CADET_ChannelInfo
 {
   /**
    * #GNUNET_YES / #GNUNET_NO, for binary flags.
    */
   int yes_no;
 
   /**
    * Peer on the other side of the channel
    */
   const struct GNUNET_PeerIdentity peer;
 };
 
 
 /**
  * Get information about a channel.
  *
  * @param channel Channel handle.
  * @param option Query (GNUNET_CADET_OPTION_*)
  * @param ... dependent on option, currently not used
  *
  * @return Union with an answer to the query.
  */
 const union GNUNET_CADET_ChannelInfo *
 GNUNET_CADET_channel_get_info (struct GNUNET_CADET_Channel *channel,
                                enum GNUNET_CADET_ChannelInfoOption option,
                                ...);
 
 
 /******************************************************************************/
 /********************       MONITORING /DEBUG API     *************************/
 /******************************************************************************/
 /* The following calls are not useful for normal CADET operation, but for      */
 /* debug and monitoring of the cadet state. They can be safely ignored.        */
 /* The API can change at any point without notice.                            */
 /* Please contact the developer if you consider any of this calls useful for  */
 /* normal cadet applications.                                                  */
 /******************************************************************************/
 
 
 /**
  * Internal details about a channel.
  */
 struct GNUNET_CADET_ChannelInternals
 {
   /**
    * Root of the channel
    */
   struct GNUNET_PeerIdentity root;
 
   /**
    * Destination of the channel
    */
   struct GNUNET_PeerIdentity dest;
 
   // to be expanded!
 };
 
 
 /**
  * Method called to retrieve information about a specific channel the cadet peer
  * is aware of, including all transit nodes.
  *
  * @param cls Closure.
  * @param info internal details, NULL for end of list
  */
 typedef void (*GNUNET_CADET_ChannelCB) (
   void *cls,
   const struct GNUNET_CADET_ChannelInternals *info);
 
 
 /**
  * Operation handle.
  */
 struct GNUNET_CADET_ChannelMonitor;
 
 
 /**
  * Request information about channels to @a peer from the local peer.
  *
  * @param cfg configuration to use
  * @param peer ID of the other end of the channel.
  * @param callback Function to call with the requested data.
  * @param callback_cls Closure for @c callback.
  */
 struct GNUNET_CADET_ChannelMonitor *
 GNUNET_CADET_get_channel (const struct GNUNET_CONFIGURATION_Handle *cfg,
                           struct GNUNET_PeerIdentity *peer,
                           GNUNET_CADET_ChannelCB callback,
                           void *callback_cls);
 
 
 /**
  * Cancel a channel monitor request. The callback will not be called (anymore).
  *
  * @param h Cadet handle.
  * @return Closure that was given to #GNUNET_CADET_get_channel().
  */
 void *
 GNUNET_CADET_get_channel_cancel (struct GNUNET_CADET_ChannelMonitor *cm);
 
 
 /**
  * Information we return per peer.
  */
 struct GNUNET_CADET_PeerListEntry
 {
   /**
    * Which peer is the information about?
    */
   struct GNUNET_PeerIdentity peer;
 
   /**
    * Do we have a tunnel to this peer?
    */
   int have_tunnel;
 
   /**
    * Number of disjoint known paths to @e peer.
    */
   unsigned int n_paths;
 
   /**
    * Length of the shortest path (0 = unknown, 1 = ourselves, 2 = direct neighbour).
    */
   unsigned int best_path_length;
 };
 
 
 /**
  * Method called to retrieve information about all peers in CADET, called
  * once per peer.
  *
  * After last peer has been reported, an additional call with NULL is done.
  *
  * @param cls Closure.
  * @param ple information about a peer, or NULL on "EOF".
  */
 typedef void (*GNUNET_CADET_PeersCB) (
   void *cls,
   const struct GNUNET_CADET_PeerListEntry *ple);
 
 
 /**
  * Operation handle.
  */
 struct GNUNET_CADET_PeersLister;
 
 
 /**
  * Request information about peers known to the running cadet service.
  * The callback will be called for every peer known to the service.
  * Only one info request (of any kind) can be active at once.
  *
  * @param cfg configuration to use
  * @param callback Function to call with the requested data.
  * @param callback_cls Closure for @c callback.
  * @return NULL on error
  */
 struct GNUNET_CADET_PeersLister *
 GNUNET_CADET_list_peers (const struct GNUNET_CONFIGURATION_Handle *cfg,
                          GNUNET_CADET_PeersCB callback,
                          void *callback_cls);
 
 
 /**
  * Cancel a peer info request. The callback will not be called (anymore).
  *
  * @param pl operation handle
  * @return Closure that was given to #GNUNET_CADET_list_peers().
  */
 void *
 GNUNET_CADET_list_peers_cancel (struct GNUNET_CADET_PeersLister *pl);
 
 
 /**
  * Detailed information we return per peer.
  */
 struct GNUNET_CADET_PeerPathDetail
 {
   /**
    * Peer this is about.
    */
   struct GNUNET_PeerIdentity peer;
 
   /**
    * Offset of the target peer on the @e path.
    */
   unsigned int target_offset;
 
   /**
    * Number of entries on the @e path.
    */
   unsigned int path_length;
 
   /**
    * Array of PEER_IDs representing all paths to reach the peer.  Each
    * path starts with the first hop (local peer not included).  Each
    * path ends with the destination peer (given in @e peer).
    */
   const struct GNUNET_PeerIdentity *path;
 };
 
 
 /**
  * Method called to retrieve information about a specific path
  * known to the service.
  *
  * @param cls Closure.
  * @param ppd details about a path to the peer, NULL for end of information
  */
 typedef void (*GNUNET_CADET_PathCB) (
   void *cls,
   const struct GNUNET_CADET_PeerPathDetail *ppd);
 
 
 /**
  * Handle to cancel #GNUNET_CADET_get_path() operation.
  */
 struct GNUNET_CADET_GetPath;
 
 
 /**
  * Request information about a peer known to the running cadet peer.
  *
  * @param cfg configuration to use
  * @param id Peer whose paths we want to examine.
  * @param callback Function to call with the requested data.
  * @param callback_cls Closure for @c callback.
  * @return NULL on error
  */
 struct GNUNET_CADET_GetPath *
 GNUNET_CADET_get_path (const struct GNUNET_CONFIGURATION_Handle *cfg,
                        const struct GNUNET_PeerIdentity *id,
                        GNUNET_CADET_PathCB callback,
                        void *callback_cls);
 
 
 /**
  * Cancel @a gp operation.
  *
  * @param gp operation to cancel
  * @return closure from #GNUNET_CADET_get_path().
  */
 void *
 GNUNET_CADET_get_path_cancel (struct GNUNET_CADET_GetPath *gp);
 
 
 /**
  * Details about a tunnel managed by CADET.
  */
 struct GNUNET_CADET_TunnelDetails
 {
   /**
    * Target of the tunnel.
    */
   struct GNUNET_PeerIdentity peer;
 
   /**
    * How many channels use the tunnel.
    */
   uint32_t channels;
 
   /**
    * How many connections support the tunnel.
    */
   uint32_t connections;
 
   /**
    * What is our encryption state?
    */
   uint16_t estate;
 
   /**
    * What is our connectivity state?
    */
   uint16_t cstate;
 };
 
 
 /**
  * Method called to retrieve information about all tunnels in CADET, called
  * once per tunnel.
  *
  * After last tunnel has been reported, an additional call with NULL is done.
  *
  * @param cls Closure.
  * @param td tunnel details, NULL for end of list
  */
 typedef void (*GNUNET_CADET_TunnelsCB) (
   void *cls,
   const struct GNUNET_CADET_TunnelDetails *td);
 
 
 /**
  * Operation handle.
  */
 struct GNUNET_CADET_ListTunnels;
 
 
 /**
  * Request information about tunnels of the running cadet peer.
  * The callback will be called for every tunnel of the service.
  * Only one info request (of any kind) can be active at once.
  *
  * @param cfg configuration to use
  * @param callback Function to call with the requested data.
  * @param callback_cls Closure for @c callback.
  * @return NULL on error
  */
 struct GNUNET_CADET_ListTunnels *
 GNUNET_CADET_list_tunnels (const struct GNUNET_CONFIGURATION_Handle *cfg,
                            GNUNET_CADET_TunnelsCB callback,
                            void *callback_cls);
 
 
 /**
  * Cancel a monitor request. The monitor callback will not be called.
  *
  * @param lt operation handle
  * @return Closure given to #GNUNET_CADET_list_tunnels(), if any.
  */
 void *
 GNUNET_CADET_list_tunnels_cancel (struct GNUNET_CADET_ListTunnels *lt);
 
 
 #if 0 /* keep Emacsens' auto-indent happy */
 {
 #endif
 #ifdef __cplusplus
 }
 #endif
 
 /* ifndef GNUNET_CADET_SERVICE_H */
 #endif
 
 /** @} */ /* end of group */
 
 /** @} */ /* end of group addition */
 
 /* end of gnunet_cadet_service.h */