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/*
This file is part of GNUnet
Copyright (C) 2021 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
*/
/**
* @author Christian Grothoff
*
* @file
* API for DHT network underlay
*/
#ifndef PLUGIN_DHTU_H
#define PLUGIN_DHTU_H
#include "gnunet_util_lib.h"
#ifdef __cplusplus
extern "C"
{
#if 0 /* keep Emacsens' auto-indent happy */
}
#endif
#endif
/**
* Opaque handle that the underlay offers for our address to be used when
* sending messages to another peer.
*/
struct GNUNET_DHTU_Source;
/**
* Opaque handle that the underlay offers for the target peer when sending
* messages to another peer.
*/
struct GNUNET_DHTU_Target;
/**
* Opaque handle expressing a preference of the DHT to
* keep a particular target connected.
*/
struct GNUNET_DHTU_PreferenceHandle;
/**
* Key used to identify peer's position in the DHT.
*/
struct GNUNET_DHTU_HashKey
{
struct GNUNET_HashCode sha512;
};
/**
* The datastore service will pass a pointer to a struct
* of this type as the first and only argument to the
* entry point of each datastore plugin.
*/
struct GNUNET_DHTU_PluginEnvironment
{
/**
* Configuration to use.
*/
const struct GNUNET_CONFIGURATION_Handle *cfg;
/**
* Closure to use for callbacks.
*/
void *cls;
/**
* Function to call with new addresses of this peer.
*
* @param cls the closure
* @param key hash position of this address in the DHT
* @param address address under which we are likely reachable,
* pointer will remain valid until @e address_del_cb is called; to be used for HELLOs. Example: "ip+udp://1.1.1.1:2086/"
* @param source handle for sending from this address, NULL if we can only receive
* @param[out] ctx storage space for DHT to use in association with this address
*/
void
(*address_add_cb)(void *cls,
struct GNUNET_DHTU_HashKey *key,
const char *address,
struct GNUNET_DHTU_Source *source,
void **ctx);
/**
* Function to call with expired addresses of this peer.
*
* @param[in] ctx storage space used by the DHT in association with this address
*/
void
(*address_del_cb)(void *ctx);
/**
* We have a new estimate on the size of the underlay.
*
* @param cls closure
* @param timestamp time when the estimate was received from the server (or created by the server)
* @param logestimate the log(Base 2) value of the current network size estimate
* @param std_dev standard deviation for the estimate, negative if unavailable
*/
void
(*network_size_cb)(void *cls,
struct GNUNET_TIME_Absolute timestamp,
double logestimate,
double std_dev);
/**
* Function to call when we connect to a peer and can henceforth transmit to
* that peer.
*
* @param cls the closure
* @param pk public key of the target,
* pointer will remain valid until @e disconnect_cb is called
* @para peer_id hash position of the peer,
* pointer will remain valid until @e disconnect_cb is called
* @param target handle to the target,
* pointer will remain valid until @e disconnect_cb is called
* @param[out] ctx storage space for DHT to use in association with this target
*/
void
(*connect_cb)(void *cls,
struct GNUNET_DHTU_Target *target,
struct GNUNET_DHTU_HashKey *key,
void **ctx);
/**
* Function to call when we disconnected from a peer and can henceforth
* cannot transmit to that peer anymore.
*
* @param[in] ctx storage space used by the DHT in association with this target
*/
void
(*disconnect_cb)(void *ctx);
/**
* Function to call when we receive a message.
*
* @param cls the closure
* @param origin where the message originated from
* @param[in,out] tctx ctx of target address where we received the message from
* @param[in,out] sctx ctx of our own source address at which we received the message
* @param message the message we received @param message_size number of
* bytes in @a message
*/
void
(*receive_cb)(void *cls,
void **tctx,
void **sctx,
const void *message,
size_t message_size);
};
/**
* @brief struct returned by the initialization function of the plugin
*/
struct GNUNET_DHTU_PluginFunctions
{
/**
* Closure to pass to all plugin functions.
*/
void *cls;
/**
* Request creation of a session with a peer at the given @a address.
*
* @param cls closure (internal context for the plugin)
* @param address target address to connect to
*/
void
(*try_connect) (void *cls,
const char *address);
/**
* Request underlay to keep the connection to @a target alive if possible.
* Hold may be called multiple times to express a strong preference to
* keep a connection, say because a @a target is in multiple tables.
*
* @param cls closure
* @param target connection to keep alive
*/
struct GNUNET_DHTU_PreferenceHandle *
(*hold)(void *cls,
struct GNUNET_DHTU_Target *target);
/**
* Do no long request underlay to keep the connection alive.
*
* @param cls closure
* @param target connection to keep alive
*/
void
(*drop)(struct GNUNET_DHTU_PreferenceHandle *ph);
/**
* Send message to some other participant over the network. Note that
* sending is not guaranteeing that the other peer actually received the
* message. For any given @a target, the DHT must wait for the @a
* finished_cb to be called before calling send() again.
*
* @param cls closure (internal context for the plugin)
* @param target receiver identification
* @param msg message
* @param msg_size number of bytes in @a msg
* @param finished_cb function called once transmission is done
* (not called if @a target disconnects, then only the
* disconnect_cb is called).
* @param finished_cb_cls closure for @a finished_cb
*/
void
(*send) (void *cls,
struct GNUNET_DHTU_Target *target,
const void *msg,
size_t msg_size,
GNUNET_SCHEDULER_TaskCallback finished_cb,
void *finished_cb_cls);
};
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif
#endif
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