/* This file is part of GNUnet. Copyright (C) 2001-2017 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. */ /** * @file cadet/gnunet-service-cadet_channel.h * @brief GNUnet CADET service with encryption * @author Bartlomiej Polot * @author Christian Grothoff */ #ifndef GNUNET_SERVICE_CADET_CHANNEL_H #define GNUNET_SERVICE_CADET_CHANNEL_H #include "gnunet-service-cadet.h" #include "gnunet-service-cadet_peer.h" #include "cadet_protocol.h" /** * A channel is a bidirectional connection between two CADET * clients. Communiation can be reliable, unreliable, in-order * or out-of-order. One client is the "local" client, this * one initiated the connection. The other client is the * "incoming" client, this one listened on a port to accept * the connection from the "local" client. */ struct CadetChannel; /** * Hash the @a port and @a initiator and @a listener to * calculate the "challenge" @a h_port we send to the other * peer on #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN. * * @param[out] h_port set to the hash of @a port, @a initiator and @a listener * @param port cadet port, as seen by CADET clients * @param listener peer that is listining on @a port */ void GCCH_hash_port (struct GNUNET_HashCode *h_port, const struct GNUNET_HashCode *port, const struct GNUNET_PeerIdentity *listener); /** * Get the static string for identification of the channel. * * @param ch Channel. * * @return Static string with the channel IDs. */ const char * GCCH_2s (const struct CadetChannel *ch); /** * Log channel info. * * @param ch Channel. * @param level Debug level to use. */ void GCCH_debug (struct CadetChannel *ch, enum GNUNET_ErrorType level); /** * Get the channel's public ID. * * @param ch Channel. * * @return ID used to identify the channel with the remote peer. */ struct GNUNET_CADET_ChannelTunnelNumber GCCH_get_id (const struct CadetChannel *ch); /** * Create a new channel. * * @param owner local client owning the channel * @param owner_id local chid of this channel at the @a owner * @param destination peer to which we should build the channel * @param port desired port at @a destination * @param options options for the channel * @return handle to the new channel */ struct CadetChannel * GCCH_channel_local_new (struct CadetClient *owner, struct GNUNET_CADET_ClientChannelNumber owner_id, struct CadetPeer *destination, const struct GNUNET_HashCode *port, uint32_t options); /** * A client is bound to the port that we have a channel * open to. Send the acknowledgement for the connection * request and establish the link with the client. * * @param ch open incoming channel * @param c client listening on the respective @a port * @param port port number @a c is listening on */ void GCCH_bind (struct CadetChannel *ch, struct CadetClient *c, const struct GNUNET_HashCode *port); /** * Destroy locally created channel. Called by the * local client, so no need to tell the client. * * @param ch channel to destroy * @param c client that caused the destruction * @param ccn client number of the client @a c */ void GCCH_channel_local_destroy (struct CadetChannel *ch, struct CadetClient *c, struct GNUNET_CADET_ClientChannelNumber ccn); /** * Function called once and only once after a channel was bound * to its tunnel via #GCT_add_channel() is ready for transmission. * Note that this is only the case for channels that this peer * initiates, as for incoming channels we assume that they are * ready for transmission immediately upon receiving the open * message. Used to bootstrap the #GCT_send() process. * * @param ch the channel for which the tunnel is now ready */ void GCCH_tunnel_up (struct CadetChannel *ch); /** * Create a new channel based on a request coming in over the network. * * @param t tunnel to the remote peer * @param chid identifier of this channel in the tunnel * @param origin peer to who initiated the channel * @param h_port hash of desired local port * @param options options for the channel * @return handle to the new channel */ struct CadetChannel * GCCH_channel_incoming_new (struct CadetTunnel *t, struct GNUNET_CADET_ChannelTunnelNumber chid, const struct GNUNET_HashCode *h_port, uint32_t options); /** * We got a #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN message again for * this channel. If the binding was successful, (re)transmit the * #GNUNET_MESSAGE_TYPE_CADET_CHANNEL_OPEN_ACK. * * @param ch channel that got the duplicate open * @param cti identifier of the connection that delivered the message */ void GCCH_handle_duplicate_open (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti); /** * We got payload data for a channel. Pass it on to the client. * * @param ch channel that got data * @param cti identifier of the connection that delivered the message * @param msg message that was received */ void GCCH_handle_channel_plaintext_data (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_CADET_ChannelAppDataMessage *msg); /** * We got an acknowledgement for payload data for a channel. * Possibly resume transmissions. * * @param ch channel that got the ack * @param cti identifier of the connection that delivered the message * @param ack details about what was received */ void GCCH_handle_channel_plaintext_data_ack (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_CADET_ChannelDataAckMessage *ack); /** * We got an acknowledgement for the creation of the channel * (the port is open on the other side). Begin transmissions. * * @param ch channel to destroy * @param cti identifier of the connection that delivered the message, * NULL if the ACK was inferred because we got payload or are on loopback * @param port port number (needed to verify receiver knows the port) */ void GCCH_handle_channel_open_ack (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti, const struct GNUNET_HashCode *port); /** * Destroy channel, based on the other peer closing the * connection. Also needs to remove this channel from * the tunnel. * * FIXME: need to make it possible to defer destruction until we have * received all messages up to the destroy, and right now the destroy * message (and this API) fails to give is the information we need! * * FIXME: also need to know if the other peer got a destroy from * us before! * * @param ch channel to destroy * @param cti identifier of the connection that delivered the message, * NULL during shutdown */ void GCCH_handle_remote_destroy (struct CadetChannel *ch, const struct GNUNET_CADET_ConnectionTunnelIdentifier *cti); /** * Handle data given by a client. * * Check whether the client is allowed to send in this tunnel, save if * channel is reliable and send an ACK to the client if there is still * buffer space in the tunnel. * * @param ch Channel. * @param sender_ccn ccn of the sender * @param buf payload to transmit. * @param buf_len number of bytes in @a buf * @return #GNUNET_OK if everything goes well, * #GNUNET_SYSERR in case of an error. */ int GCCH_handle_local_data (struct CadetChannel *ch, struct GNUNET_CADET_ClientChannelNumber sender_ccn, const char *buf, size_t buf_len); /** * Handle ACK from client on local channel. * * @param ch channel to destroy * @param client_ccn ccn of the client sending the ack */ void GCCH_handle_local_ack (struct CadetChannel *ch, struct GNUNET_CADET_ClientChannelNumber client_ccn); #endif