/* This file is part of GNUnet. (C) 2009-2014 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 include/gnunet_cadet_service.h * @brief cadet service; establish channels to distant peers * @author Christian Grothoff * @author Bart Polot */ #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 0x00000003 /** * Opaque handle to the service. */ struct GNUNET_CADET_Handle; /** * Opaque handle to a channel. */ struct GNUNET_CADET_Channel; /** * Hash to be used in Cadet communication. Only 256 bits needed, * instead of the 512 from `struct GNUNET_HashCode`. */ struct GNUNET_CADET_Hash { unsigned char bits[256 / 8]; }; /** * 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. * Yes/No. */ GNUNET_CADET_OPTION_OOORDER = 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 }; /** * Functions with this signature are called whenever a message is * received. * * Each time the function must call #GNUNET_CADET_receive_done on the channel * in order to receive the next message. This doesn't need to be immediate: * can be delayed if some processing is done on the message. * * @param cls Closure (set from #GNUNET_CADET_connect). * @param channel Connection to the other end. * @param channel_ctx Place to store local state associated with the channel. * @param message The actual message. * @return #GNUNET_OK to keep the channel open, * #GNUNET_SYSERR to close it (signal serious error). */ typedef int (*GNUNET_CADET_MessageCallback) (void *cls, struct GNUNET_CADET_Channel *channel, void **channel_ctx, const struct GNUNET_MessageHeader *message); /** * Message handler. Each struct specifies how to handle on particular * type of message received. */ struct GNUNET_CADET_MessageHandler { /** * Function to call for messages of type @e type. */ GNUNET_CADET_MessageCallback callback; /** * Type of the message this handler covers. */ uint16_t type; /** * Expected size of messages of this type. Use 0 for variable-size. * If non-zero, messages of the given type will be discarded if they * do not have the right size. */ uint16_t expected_size; }; /** * Method called whenever another peer has added us to a channel * the other peer initiated. * Only called (once) upon reception of data with a message type which was * subscribed to in #GNUNET_CADET_connect. * * A call to #GNUNET_CADET_channel_destroy causes te channel to be ignored. In * this case the handler MUST return NULL. * * @param cls closure * @param channel new handle to the channel * @param initiator peer that started the channel * @param port Port this channel is for. * @param options CadetOption flag field, with all active option bits set to 1. * * @return initial channel context for the channel * (can be NULL -- that's not an error) */ typedef void * (GNUNET_CADET_InboundChannelNotificationHandler) (void *cls, struct GNUNET_CADET_Channel *channel, const struct GNUNET_PeerIdentity *initiator, uint32_t port, enum GNUNET_CADET_ChannelOption options); /** * Function called whenever a channel is destroyed. Should clean up * any associated state, including cancelling any pending transmission on this * channel. * * It must NOT call #GNUNET_CADET_channel_destroy on the channel. * * @param cls closure (set from #GNUNET_CADET_connect) * @param channel connection to the other end (henceforth invalid) * @param channel_ctx place where local state associated * with the channel is stored */ typedef void (GNUNET_CADET_ChannelEndHandler) (void *cls, const struct GNUNET_CADET_Channel *channel, void *channel_ctx); /** * Connect to the cadet service. * * @param cfg Configuration to use. * @param cls Closure for the various callbacks that follow (including * handlers in the handlers array). * @param new_channel Function called when an *incoming* channel is created. * Can be NULL if no inbound channels are desired. * See @a ports. * @param cleaner Function called when a channel is destroyed. * It is called immediately if #GNUNET_CADET_channel_destroy * is called on the channel. * @param handlers Callbacks for messages we care about, NULL-terminated. Each * one must call #GNUNET_CADET_receive_done on the channel to * receive the next message. Messages of a type that is not * in the handlers array are ignored if received. * @param ports NULL or 0-terminated array of port numbers for incoming channels. * See @a new_channel. * * @return handle to the cadet service NULL on error * (in this case, init is never called) */ struct GNUNET_CADET_Handle * GNUNET_CADET_connect (const struct GNUNET_CONFIGURATION_Handle *cfg, void *cls, GNUNET_CADET_InboundChannelNotificationHandler new_channel, GNUNET_CADET_ChannelEndHandler cleaner, const struct GNUNET_CADET_MessageHandler *handlers, const uint32_t *ports); /** * 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); /** * 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, #GNUNET_CADET_ChannelEndHandler will be called * for this channel. * * @param h cadet handle * @param channel_ctx client's channel context to associate with the channel * @param peer peer identity the channel should go to * @param port Port number. * @param options CadetOption flag field, with all desired option bits set to 1. * * @return handle to the channel */ struct GNUNET_CADET_Channel * GNUNET_CADET_channel_create (struct GNUNET_CADET_Handle *h, void *channel_ctx, const struct GNUNET_PeerIdentity *peer, uint32_t port, enum GNUNET_CADET_ChannelOption options); /** * Destroy an existing channel. * * The existing end callback for the channel will be called immediately. * 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); /** * Struct 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, ...); /** * Handle for a transmission request. */ struct GNUNET_CADET_TransmitHandle; /** * Ask the cadet to call @a notify once it is ready to transmit the * given number of bytes to the specified channel. * Only one call can be active at any time, to issue another request, * wait for the callback or cancel the current request. * * @param channel channel to use for transmission * @param cork is corking allowed for this transmission? * @param maxdelay how long can the message wait? * @param notify_size how many bytes of buffer space does notify want? * @param notify function to call when buffer space is available; * will be called with NULL on timeout or if the overall queue * for this peer is larger than queue_size and this is currently * the message with the lowest priority * @param notify_cls closure for @a notify * @return non-NULL if the notify callback was queued, * NULL if we can not even queue the request (insufficient * memory); if NULL is returned, @a notify will NOT be called. */ struct GNUNET_CADET_TransmitHandle * GNUNET_CADET_notify_transmit_ready (struct GNUNET_CADET_Channel *channel, int cork, struct GNUNET_TIME_Relative maxdelay, size_t notify_size, GNUNET_CONNECTION_TransmitReadyNotify notify, void *notify_cls); /** * Cancel the specified transmission-ready notification. * * @param th handle that was returned by "notify_transmit_ready". */ void GNUNET_CADET_notify_transmit_ready_cancel (struct GNUNET_CADET_TransmitHandle *th); /** * 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); /******************************************************************************/ /******************** 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. */ /******************************************************************************/ /** * Method called to retrieve information about a specific channel the cadet peer * is aware of, including all transit nodes. * * @param cls Closure. * @param root Root of the channel. * @param dest Destination of the channel. * @param port Destination port of the channel. * @param root_channel_number Local number for root, if known. * @param dest_channel_number Local number for dest, if known. * @param public_channel_numbe Number for P2P, always known. */ typedef void (*GNUNET_CADET_ChannelCB) (void *cls, const struct GNUNET_PeerIdentity *root, const struct GNUNET_PeerIdentity *dest, uint32_t port, uint32_t root_channel_number, uint32_t dest_channel_number, uint32_t public_channel_number); /** * 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 peer Peer, or NULL on "EOF". * @param tunnel Do we have a tunnel towards this peer? * @param n_paths Number of known paths towards this peer. * @param best_path How long is the best path? * (0 = unknown, 1 = ourselves, 2 = neighbor) */ typedef void (*GNUNET_CADET_PeersCB) (void *cls, const struct GNUNET_PeerIdentity *peer, int tunnel, unsigned int n_paths, unsigned int best_path); /** * Method called to retrieve information about a specific peer * known to the service. * * @param cls Closure. * @param peer Peer ID. * @param tunnel Do we have a tunnel towards this peer? #GNUNET_YES/#GNUNET_NO * @param neighbor Is this a direct neighbor? #GNUNET_YES/#GNUNET_NO * @param n_paths Number of paths known towards peer. * @param paths Array of PEER_IDs representing all paths to reach the peer. * Each path starts with the local peer. * Each path ends with the destination peer (given in @c peer). */ typedef void (*GNUNET_CADET_PeerCB) (void *cls, const struct GNUNET_PeerIdentity *peer, int tunnel, int neighbor, unsigned int n_paths, struct GNUNET_PeerIdentity *paths); /** * 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 peer Destination peer, or NULL on "EOF". * @param channels Number of channels. * @param connections Number of connections. * @param estate Encryption state. * @param cstate Connectivity state. */ typedef void (*GNUNET_CADET_TunnelsCB) (void *cls, const struct GNUNET_PeerIdentity *peer, unsigned int channels, unsigned int connections, uint16_t estate, uint16_t cstate); /** * Method called to retrieve information about a specific tunnel the cadet peer * has established, o`r is trying to establish. * * @param cls Closure. * @param peer Peer towards whom the tunnel is directed. * @param n_channels Number of channels. * @param n_connections Number of connections. * @param channels Channels. * @param connections Connections. * @param estate Encryption state. * @param cstate Connectivity state. */ typedef void (*GNUNET_CADET_TunnelCB) (void *cls, const struct GNUNET_PeerIdentity *peer, unsigned int n_channels, unsigned int n_connections, uint32_t *channels, struct GNUNET_CADET_Hash *connections, unsigned int estate, unsigned int cstate); /** * Request information about a specific channel of the running cadet peer. * * WARNING: unstable API, likely to change in the future! * * @param h Handle to the cadet peer. * @param peer ID of the other end of the channel. * @param channel_number Channel number. * @param callback Function to call with the requested data. * @param callback_cls Closure for @c callback. */ void GNUNET_CADET_get_channel (struct GNUNET_CADET_Handle *h, struct GNUNET_PeerIdentity *peer, uint32_t channel_number, GNUNET_CADET_ChannelCB callback, void *callback_cls); /** * Request a debug dump on the service's STDERR. * * WARNING: unstable API, likely to change in the future! * * @param h cadet handle */ void GNUNET_CADET_request_dump (struct GNUNET_CADET_Handle *h); /** * 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. * * * WARNING: unstable API, likely to change in the future! * * @param h Handle to the cadet peer. * @param callback Function to call with the requested data. * @param callback_cls Closure for @c callback. * * @return #GNUNET_OK / #GNUNET_SYSERR */ int GNUNET_CADET_get_peers (struct GNUNET_CADET_Handle *h, GNUNET_CADET_PeersCB callback, void *callback_cls); /** * Cancel a peer info request. The callback will not be called (anymore). * * WARNING: unstable API, likely to change in the future! * * @param h Cadet handle. * * @return Closure that was given to #GNUNET_CADET_get_peers(). */ void * GNUNET_CADET_get_peers_cancel (struct GNUNET_CADET_Handle *h); /** * Request information about a peer known to the running cadet peer. * The callback will be called for the tunnel once. * Only one info request (of any kind) can be active at once. * * WARNING: unstable API, likely to change in the future! * * @param h Handle to the cadet peer. * @param id Peer whose tunnel to examine. * @param callback Function to call with the requested data. * @param callback_cls Closure for @c callback. * * @return #GNUNET_OK / #GNUNET_SYSERR */ int GNUNET_CADET_get_peer (struct GNUNET_CADET_Handle *h, const struct GNUNET_PeerIdentity *id, GNUNET_CADET_PeerCB callback, void *callback_cls); /** * 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. * * WARNING: unstable API, likely to change in the future! * * @param h Handle to the cadet peer. * @param callback Function to call with the requested data. * @param callback_cls Closure for @c callback. * * @return #GNUNET_OK / #GNUNET_SYSERR */ int GNUNET_CADET_get_tunnels (struct GNUNET_CADET_Handle *h, GNUNET_CADET_TunnelsCB callback, void *callback_cls); /** * Cancel a monitor request. The monitor callback will not be called. * * @param h Cadet handle. * * @return Closure given to #GNUNET_CADET_get_tunnels(), if any. */ void * GNUNET_CADET_get_tunnels_cancel (struct GNUNET_CADET_Handle *h); /** * Request information about a tunnel of the running cadet peer. * The callback will be called for the tunnel once. * Only one info request (of any kind) can be active at once. * * WARNING: unstable API, likely to change in the future! * * @param h Handle to the cadet peer. * @param id Peer whose tunnel to examine. * @param callback Function to call with the requested data. * @param callback_cls Closure for @c callback. * * @return #GNUNET_OK / #GNUNET_SYSERR */ int GNUNET_CADET_get_tunnel (struct GNUNET_CADET_Handle *h, const struct GNUNET_PeerIdentity *id, GNUNET_CADET_TunnelCB callback, void *callback_cls); /** * Create a message queue for a cadet channel. * The message queue can only be used to transmit messages, * not to receive them. * * @param channel the channel to create the message qeue for * @return a message queue to messages over the channel */ struct GNUNET_MQ_Handle * GNUNET_CADET_mq_create (struct GNUNET_CADET_Channel *channel); #if 0 /* keep Emacsens' auto-indent happy */ { #endif #ifdef __cplusplus } #endif /* ifndef GNUNET_CADET_SERVICE_H */ #endif /* end of gnunet_cadet_service.h */