/* This file is part of GNUnet. Copyright (C) 2009-2018 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 . */ /** * @author Christian Grothoff * * @file * API of the transport service towards the communicator processes. * * @defgroup transport TRANSPORT service * Low-level communication with other peers * * @see [Documentation](https://gnunet.org/transport-service) * * @{ */ #ifndef GNUNET_TRANSPORT_COMMUNICATION_SERVICE_H #define GNUNET_TRANSPORT_COMMUNICATION_SERVICE_H #ifdef __cplusplus extern "C" { #if 0 /* keep Emacsens' auto-indent happy */ } #endif #endif #include "gnunet_util_lib.h" /** * Version number of the transport communication API. */ #define GNUNET_TRANSPORT_COMMUNICATION_VERSION 0x00000000 /** * Function called by the transport service to initialize a * message queue given address information about another peer. * If and when the communication channel is established, the * communicator must call #GNUNET_TRANSPORT_communicator_mq_add() * to notify the service that the channel is now up. It is * the responsibility of the communicator to manage sane * retries and timeouts for any @a peer/@a address combination * provided by the transport service. Timeouts and retries * do not need to be signalled to the transport service. * * @param cls closure * @param peer identity of the other peer * @param address where to send the message, human-readable * communicator-specific format, 0-terminated, UTF-8 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the provided address is invalid */ typedef int (*GNUNET_TRANSPORT_CommunicatorMqInit) (void *cls, const struct GNUNET_PeerIdentity *peer, const char *address); /** * Opaque handle to the transport service for communicators. */ struct GNUNET_TRANSPORT_CommunicatorHandle; /** * What characteristics does this communicator have? */ enum GNUNET_TRANSPORT_CommunicatorCharacteristics { /** * Characteristics are unknown (i.e. DV). */ GNUNET_TRANSPORT_CC_UNKNOWN = 0, /** * Transmission is reliabile (with ACKs), i.e. TCP/HTTP/HTTPS. */ GNUNET_TRANSPORT_CC_RELIABLE = 1, /** * Transmission is unreliable (i.e. UDP) */ GNUNET_TRANSPORT_CC_UNRELIABILE = 2 }; /** * Connect to the transport service. * * @param cfg configuration to use * @param config_section section of the configuration to use for options * @param addr_prefix address prefix for addresses supported by this * communicator, could be NULL for incoming-only communicators * @param cc what characteristics does the communicator have? * @param mq_init function to call to initialize a message queue given * the address of another peer, can be NULL if the * communicator only supports receiving messages * @param mq_init_cls closure for @a mq_init * @return NULL on error */ struct GNUNET_TRANSPORT_CommunicatorHandle * GNUNET_TRANSPORT_communicator_connect (const struct GNUNET_CONFIGURATION_Handle *cfg, const char *config_section_name, const char *addr_prefix, enum GNUNET_TRANSPORT_CommunicatorCharacteristics cc, GNUNET_TRANSPORT_CommunicatorMqInit mq_init, void *mq_init_cls); /** * Disconnect from the transport service. * * @param ch handle returned from connect */ void GNUNET_TRANSPORT_communicator_disconnect (struct GNUNET_TRANSPORT_CommunicatorHandle *ch); /* ************************* Receiving *************************** */ /** * Function called to notify communicator that we have received * and processed the message. * * @param cls closure * @param success #GNUNET_SYSERR on failure (try to disconnect/reset connection) * #GNUNET_OK on success */ typedef void (*GNUNET_TRANSPORT_MessageCompletedCallback) (void *cls, int success); /** * Notify transport service that the communicator has received * a message. * * @param handle connection to transport service * @param sender presumed sender of the message (details to be checked * by higher layers) * @param msg the message * @param cb function to call once handling the message is done, NULL if * flow control is not supported by this communicator * @param cb_cls closure for @a cb * @return #GNUNET_OK if all is well, #GNUNET_NO if the message was * immediately dropped due to memory limitations (communicator * should try to apply back pressure), * #GNUNET_SYSERR if the message could not be delivered because * the tranport service is not yet up */ int GNUNET_TRANSPORT_communicator_receive (struct GNUNET_TRANSPORT_CommunicatorHandle *handle, const struct GNUNET_PeerIdentity *sender, const struct GNUNET_MessageHeader *msg, GNUNET_TRANSPORT_MessageCompletedCallback cb, void *cb_cls); /* ************************* Discovery *************************** */ /** * Handle returned to identify the internal data structure the transport * API has created to manage a message queue to a particular peer. */ struct GNUNET_TRANSPORT_QueueHandle; /** * Possible states of a connection. */ enum GNUNET_TRANSPORT_ConnectionStatus { /** * Connection is down. */ GNUNET_TRANSPORT_CS_DOWN = -1, /** * this is an outbound connection (transport initiated) */ GNUNET_TRANSPORT_CS_OUTBOUND = 0, /** * this is an inbound connection (communicator initiated) */ GNUNET_TRANSPORT_CS_INBOUND = 1 }; /** * Notify transport service that an MQ became available due to an * "inbound" connection or because the communicator discovered the * presence of another peer. * * @param ch connection to transport service * @param peer peer with which we can now communicate * @param address address in human-readable format, 0-terminated, UTF-8 * @param mtu maximum message size supported by queue, 0 if * sending is not supported, SIZE_MAX for no MTU * @param nt which network type does the @a address belong to? * @param distance how many hops does this queue use (DV-only)? * @param cs what is the connection status of the queue? * @param mq message queue of the @a peer * @return API handle identifying the new MQ */ struct GNUNET_TRANSPORT_QueueHandle * GNUNET_TRANSPORT_communicator_mq_add (struct GNUNET_TRANSPORT_CommunicatorHandle *ch, const struct GNUNET_PeerIdentity *peer, const char *address, uint32_t mtu, enum GNUNET_NetworkType nt, uint32_t distance, enum GNUNET_TRANSPORT_ConnectionStatus cs, struct GNUNET_MQ_Handle *mq); /** * Notify transport service that an MQ became unavailable due to a * disconnect or timeout. * * @param qh handle for the queue that must be invalidated */ void GNUNET_TRANSPORT_communicator_mq_del (struct GNUNET_TRANSPORT_QueueHandle *qh); /** * Internal representation of an address a communicator is * currently providing for the transport service. */ struct GNUNET_TRANSPORT_AddressIdentifier; /** * Notify transport service about an address that this communicator * provides for this peer. * * @param ch connection to transport service * @param address our address in human-readable format, 0-terminated, UTF-8 * @param nt which network type does the address belong to? * @param expiration when does the communicator forsee this address expiring? */ struct GNUNET_TRANSPORT_AddressIdentifier * GNUNET_TRANSPORT_communicator_address_add (struct GNUNET_TRANSPORT_CommunicatorHandle *ch, const char *address, enum GNUNET_NetworkType nt, struct GNUNET_TIME_Relative expiration); /** * Notify transport service about an address that this communicator * no longer provides for this peer. * * @param ai address that is no longer provided */ void GNUNET_TRANSPORT_communicator_address_remove (struct GNUNET_TRANSPORT_AddressIdentifier *ai); #if 0 /* keep Emacsens' auto-indent happy */ { #endif #ifdef __cplusplus } #endif /* ifndef GNUNET_TRANSPORT_COMMUNICATOR_SERVICE_H */ #endif /** @} */ /* end of group */ /* end of gnunet_transport_communicator_service.h */