/* 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 . SPDX-License-Identifier: AGPL3.0-or-later */ /** * @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" #include "gnunet_transport_service.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 identfies * 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; }; /** * Channel options. Second line indicates filed in the * CadetChannelInfo union carrying the answer. */ enum GNUNET_CADET_ChannelOption { /** * Default options: unreliable, default buffering, not out of order. */ GNUNET_CADET_OPTION_DEFAULT = 0x0, /** * Disable buffering on intermediate nodes (for minimum latency). * Yes/No. */ GNUNET_CADET_OPTION_NOBUFFER = 0x1, /** * Enable channel reliability, lost messages will be retransmitted. * Yes/No. */ GNUNET_CADET_OPTION_RELIABLE = 0x2, /** * Enable out of order delivery of messages. * Set bit for out-of-order delivery. */ GNUNET_CADET_OPTION_OUT_OF_ORDER = 0x4, /** * 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 = 0x8 }; /** * 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 incomming 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 port is not open by any peer or the destination peer * does not accept the channel, @a disconnects will be called * for this channel. * * @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 options CadetOption flag field, with all desired option bits set to 1. * @param window_changes Function called when the transmit window size changes. * Can be NULL if this data is of no interest. * TODO Not yet implemented. * @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, enum GNUNET_CADET_ChannelOption options, 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); /** * 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 type GNUNET_CADET_OPTION_* * @param ... dependant 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_ChannelOption 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 gnunet_cadet_service.h */