/*
This file is part of GNUnet
Copyright (C) 2009-2014 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
*
* @file
* Transport service plugin API
*
* @defgroup transport-plugin Transport Service plugin API
*
* Specifies the struct that is given to the plugin's entry method and the other
* struct that must be returned. Note that the destructors of transport plugins
* will be given the value returned by the constructor and is expected to return
* a NULL pointer.
*
* @{
*/
#ifndef PLUGIN_TRANSPORT_H
#define PLUGIN_TRANSPORT_H
#include "gnunet_configuration_lib.h"
#include "gnunet_scheduler_lib.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_ats_service.h"
#define TRANSPORT_SESSION_INBOUND_STRING ""
/**
* Opaque pointer that plugins can use to distinguish specific
* connections to a given peer. Typically used by stateful plugins to
* allow the service to refer to specific streams instead of a more
* general notion of "some connection" to the given peer. This is
* useful since sometimes (i.e. for inbound TCP connections) a
* connection may not have an address that can be used for meaningful
* distinction between sessions to the same peer.
*
* Each 'struct GNUNET_ATS_Session' MUST start with the 'struct GNUNET_PeerIdentity'
* of the peer the session is for (which will be used for some error
* checking by the ATS code).
*/
struct GNUNET_ATS_Session;
/**
* Function that will be called whenever the plugin internally
* cleans up a session pointer and hence the service needs to
* discard all of those sessions as well. Plugins that do not
* use sessions can simply omit calling this function and always
* use NULL wherever a session pointer is needed. This function
* should be called BEFORE a potential "TransmitContinuation"
* from the "TransmitFunction".
*
* @param cls closure
* @param peer which peer was the session for
* @param session which session is being destroyed
*/
typedef void
(*GNUNET_TRANSPORT_SessionEnd) (void *cls,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session);
/**
* Plugin tells transport service about a new inbound session
*
* @param cls unused
* @param address the address
* @param session the new session
* @param net network information
*/
typedef void
(*GNUNET_TRANSPORT_SessionStart) (void *cls,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session,
enum GNUNET_NetworkType net);
/**
* Function called by the transport for each received message.
* This function should also be called with "NULL" for the
* message to signal that the other peer disconnected.
*
* @param cls closure
* @param peer (claimed) identity of the other peer
* @param message the message, NULL if we only care about
* learning about the delay until we should receive again
* @param session identifier used for this session (NULL for plugins
* that do not offer bi-directional communication to the sender
* using the same "connection")
* @param sender_address binary address of the sender (if we established the
* connection or are otherwise sure of it; should be NULL
* for inbound TCP/UDP connections since it it not clear
* that we could establish ourselves a connection to that
* IP address and get the same system)
* @param sender_address_len number of bytes in @a sender_address
* @return how long the plugin should wait until receiving more data;
* returning #GNUNET_TIME_UNIT_FOREVER_REL means that the
* connection should be closed
*/
typedef struct GNUNET_TIME_Relative
(*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session,
const struct GNUNET_MessageHeader *message);
/**
* Function that can be called by plugins to figure if an address is
* an loopback, LAN or WAN address. Ultimately invokes
* #GNUNET_ATS_address_get_type().
*
* @param cls closure
* @param addr binary address
* @param addrlen length of the @a addr
* @return type of the network the address belongs to
*/
typedef enum GNUNET_NetworkType
(*GNUNET_TRANSPORT_AddressToType) (void *cls,
const struct sockaddr *addr,
size_t addrlen);
/**
* Function called when distance of an address changes.
*
* @param cls closure
* @param peer peer
* @param distance new distance
*/
typedef void
(*GNUNET_TRANSPORT_UpdateAddressDistance) (void *cls,
const struct GNUNET_HELLO_Address *address,
uint32_t distance);
/**
* Function that will be called for each address the transport
* is aware that it might be reachable under.
*
* @param cls closure
* @param add_remove should the address added (#GNUNET_YES) or removed (#GNUNET_NO) from the
* set of valid addresses?
* @param address the address to add or remove
*/
typedef void
(*GNUNET_TRANSPORT_AddressNotification) (void *cls,
int add_remove,
const struct GNUNET_HELLO_Address *address);
/**
* Function that will be called whenever the plugin receives data over
* the network and wants to determine how long it should wait until
* the next time it reads from the given peer. Note that some plugins
* (such as UDP) may not be able to wait (for a particular peer), so
* the waiting part is optional. Plugins that can wait should call
* this function, sleep the given amount of time, and call it again
* (with zero bytes read) UNTIL it returns zero and only then read.
*
* @param cls closure
* @param peer which peer did we read data from
* @param amount_recved number of bytes read (can be zero)
* @return how long to wait until reading more from this peer
* (to enforce inbound quotas); returning #GNUNET_TIME_UNIT_FOREVER_REL
* means that the connection should be closed
*/
typedef struct GNUNET_TIME_Relative
(*GNUNET_TRANSPORT_TrafficReport) (void *cls,
const struct GNUNET_PeerIdentity *peer,
size_t amount_recved);
/**
* Function that returns a HELLO message.
*
* @return HELLO message (FIXME with what?)
*/
typedef const struct GNUNET_MessageHeader *
(*GNUNET_TRANSPORT_GetHelloCallback) (void);
/**
* The transport service will pass a pointer to a struct
* of this type as the first and only argument to the
* entry point of each transport plugin.
*/
struct GNUNET_TRANSPORT_PluginEnvironment
{
/**
* Configuration to use.
*/
const struct GNUNET_CONFIGURATION_Handle *cfg;
/**
* Identity of this peer.
*/
const struct GNUNET_PeerIdentity *my_identity;
/**
* Closure for the various callbacks.
*/
void *cls;
/**
* Handle for reporting statistics.
*/
struct GNUNET_STATISTICS_Handle *stats;
/**
* Function that should be called by the transport plugin
* whenever a message is received. If this field is "NULL",
* the plugin should load in 'stub' mode and NOT fully
* initialize and instead only return an API with the
* @e address_pretty_printer, @e address_to_string and
* @e string_to_address functions.
*/
GNUNET_TRANSPORT_PluginReceiveCallback receive;
/**
* Function that returns our HELLO.
*/
GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
/**
* Function that must be called by each plugin to notify the
* transport service about the addresses under which the transport
* provided by the plugin can be reached.
*/
GNUNET_TRANSPORT_AddressNotification notify_address;
/**
* Function that must be called by the plugin when a non-NULL
* session handle stops being valid (is destroyed).
*/
GNUNET_TRANSPORT_SessionEnd session_end;
/**
* Function called by the plugin when a new (incoming) session was created
* not explicitly created using the the get_session function
*/
GNUNET_TRANSPORT_SessionStart session_start;
/**
* Function that will be called to figure if an address is an loopback,
* LAN, WAN etc. address
*/
GNUNET_TRANSPORT_AddressToType get_address_type;
/**
* Function that will be called by DV to update distance for
* an address.
*/
GNUNET_TRANSPORT_UpdateAddressDistance update_address_distance;
/**
* What is the maximum number of connections that this transport
* should allow? Transports that do not have sessions (such as
* UDP) can ignore this value.
*/
uint32_t max_connections;
};
/**
* Function called by the #GNUNET_TRANSPORT_TransmitFunction
* upon "completion". In the case that a peer disconnects,
* this function must be called for each pending request
* (with a 'failure' indication) AFTER notifying the service
* about the disconnect event (so that the service won't try
* to transmit more messages, believing the connection still
* exists...).
*
* @param cls closure
* @param target who was the recipient of the message?
* @param result #GNUNET_OK on success
* #GNUNET_SYSERR if the target disconnected;
* disconnect will ALSO be signalled using
* the ReceiveCallback.
* @param size_payload bytes of payload from transport service in message
* @param size_on_wire bytes required on wire for transmission,
* 0 if result == #GNUNET_SYSERR
*/
typedef void
(*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
const struct GNUNET_PeerIdentity *target,
int result,
size_t size_payload,
size_t size_on_wire);
/**
* The new send function with just the session and no address
*
* Function that can be used by the transport service to transmit
* a message using the plugin. Note that in the case of a
* peer disconnecting, the continuation MUST be called
* prior to the disconnect notification itself. This function
* will be called with this peer's HELLO message to initiate
* a fresh connection to another peer.
*
* @param cls closure
* @param session which session must be used
* @param msgbuf the message to transmit
* @param msgbuf_size number of bytes in @a msgbuf
* @param priority how important is the message (most plugins will
* ignore message priority and just FIFO)
* @param to how long to wait at most for the transmission (does not
* require plugins to discard the message after the timeout,
* just advisory for the desired delay; most plugins will ignore
* this as well)
* @param cont continuation to call once the message has
* been transmitted (or if the transport is ready
* for the next transmission call; or if the
* peer disconnected...); can be NULL
* @param cont_cls closure for @a cont
* @return number of bytes used (on the physical network, with overheads);
* -1 on hard errors (i.e. address invalid); 0 is a legal value
* and does NOT mean that the message was not transmitted (DV)
*/
typedef ssize_t
(*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
struct GNUNET_ATS_Session *session,
const char *msgbuf,
size_t msgbuf_size,
unsigned int priority,
struct GNUNET_TIME_Relative to,
GNUNET_TRANSPORT_TransmitContinuation cont,
void *cont_cls);
/**
* Function that can be called to force a disconnect from the
* specified neighbour for the given session only. . This should
* also cancel all previously scheduled transmissions for this
* session. Obviously the transmission may have been partially
* completed already, which is OK. The plugin is supposed to close
* the connection (if applicable).
*
* @param cls closure with the `struct Plugin`
* @param session session to destroy
* @return #GNUNET_OK on success
*/
typedef int
(*GNUNET_TRANSPORT_DisconnectSessionFunction) (void *cls,
struct GNUNET_ATS_Session *session);
/**
* Function that is called to get the keepalive factor.
* #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
* calculate the interval between keepalive packets.
*
* @param cls closure with the `struct Plugin`
* @return keepalive factor
*/
typedef unsigned int
(*GNUNET_TRANSPORT_QueryKeepaliveFactorFunction) (void *cls);
/**
* Function that can be called to force a disconnect from the
* specified neighbour. This should also cancel all previously
* scheduled transmissions. Obviously the transmission may have been
* partially completed already, which is OK. The plugin is supposed
* to close the connection (if applicable) and no longer call the
* transmit continuation(s).
*
* @param cls closure
* @param target peer for which the last transmission is
* to be cancelled
*/
typedef void
(*GNUNET_TRANSPORT_DisconnectPeerFunction) (void *cls,
const struct GNUNET_PeerIdentity *target);
/**
* Function called by the pretty printer for the resolved address for
* each human-readable address obtained. The callback can be called
* several times. The last invocation must be with a @a address of
* NULL and a @a res of #GNUNET_OK. Thus, to indicate conversion
* errors, the callback might be called first with @a address NULL and
* @a res being #GNUNET_SYSERR. In that case, there must still be a
* subsequent call later with @a address NULL and @a res #GNUNET_OK.
*
* @param cls closure
* @param address one of the names for the host, NULL on last callback
* @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on failure,
* #GNUNET_OK on last callback
*/
typedef void
(*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
const char *address,
int res);
/**
* Convert the transports address to a nice, human-readable
* format.
*
* @param cls closure
* @param type name of the transport that generated the address
* @param addr one of the addresses of the host, NULL for the last address
* the specific address format depends on the transport
* @param addrlen length of the @a addr
* @param numeric should (IP) addresses be displayed in numeric form?
* @param timeout after how long should we give up?
* @param asc function to call on each string
* @param asc_cls closure for @a asc
*/
typedef void
(*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
const char *type,
const void *addr,
size_t addrlen,
int numeric,
struct GNUNET_TIME_Relative timeout,
GNUNET_TRANSPORT_AddressStringCallback asc,
void *asc_cls);
/**
* Another peer has suggested an address for this peer and transport
* plugin. Check that this could be a valid address. This function
* is not expected to 'validate' the address in the sense of trying to
* connect to it but simply to see if the binary format is technically
* legal for establishing a connection to this peer (and make sure that
* the address really corresponds to our network connection/settings
* and not some potential man-in-the-middle).
*
* @param addr pointer to the address
* @param addrlen length of @a addr
* @return #GNUNET_OK if this is a plausible address for this peer
* and transport, #GNUNET_SYSERR if not
*/
typedef int
(*GNUNET_TRANSPORT_CheckAddress) (void *cls,
const void *addr,
size_t addrlen);
/**
* Create a new session to transmit data to the target
* This session will used to send data to this peer and the plugin will
* notify us by calling the env->session_end function
*
* @param cls the plugin
* @param address the hello address
* @return the session if the address is valid, NULL otherwise
*/
typedef struct GNUNET_ATS_Session *
(*GNUNET_TRANSPORT_CreateSession) (void *cls,
const struct GNUNET_HELLO_Address *address);
/**
* Function that will be called whenever the transport service wants to
* notify the plugin that a session is still active and in use and
* therefore the session timeout for this session has to be updated
*
* @param cls closure
* @param peer which peer was the session for
* @param session which session is being updated
*/
typedef void
(*GNUNET_TRANSPORT_UpdateSessionTimeout) (void *cls,
const struct GNUNET_PeerIdentity *peer,
struct GNUNET_ATS_Session *session);
/**
* Function that will be called whenever the transport service wants to
* notify the plugin that the inbound quota changed and that the plugin
* should update it's delay for the next receive value
*
* @param cls closure
* @param peer which peer was the session for
* @param session which session is being updated
* @param delay new delay to use for receiving
*/
typedef void
(*GNUNET_TRANSPORT_UpdateInboundDelay) (void *cls,
const struct GNUNET_PeerIdentity *peer,
struct GNUNET_ATS_Session *session,
struct GNUNET_TIME_Relative delay);
/**
* Function called for a quick conversion of the binary address to
* a numeric address. Note that the caller must not free the
* address and that the next call to this function is allowed
* to override the address again.
*
* @param cls closure
* @param addr binary address
* @param addr_len length of the @a addr
* @return string representing the same address
*/
typedef const char *
(*GNUNET_TRANSPORT_AddressToString) (void *cls,
const void *addr,
size_t addrlen);
/**
* Function called to convert a string address to
* a binary address.
*
* @param cls closure (`struct Plugin*`)
* @param addr string address
* @param addrlen length of the @a addr including \0 termination
* @param buf location to store the buffer
* If the function returns #GNUNET_SYSERR, its contents are undefined.
* @param added length of created address
* @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
*/
typedef int
(*GNUNET_TRANSPORT_StringToAddress) (void *cls,
const char *addr,
uint16_t addrlen,
void **buf,
size_t *added);
/**
* Function to obtain the network type for a session
*
* @param cls closure (`struct Plugin *`)
* @param session the session
* @return the network type
*/
typedef enum GNUNET_NetworkType
(*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
struct GNUNET_ATS_Session *session);
/**
* Function to obtain the network type for an address.
*
* @param cls closure (`struct Plugin *`)
* @param address the address
* @return the network type
*/
typedef enum GNUNET_NetworkType
(*GNUNET_TRANSPORT_GetNetworkTypeForAddress) (void *cls,
const struct GNUNET_HELLO_Address *address);
/**
* Function called by the plugin with information about the
* current sessions managed by the plugin (for monitoring).
*
* @param cls closure
* @param session session handle this information is about,
* NULL to indicate that we are "in sync" (initial
* iteration complete)
* @param info information about the state of the session,
* NULL if @a session is also NULL and we are
* merely signalling that the initial iteration is over
*/
typedef void
(*GNUNET_TRANSPORT_SessionInfoCallback) (void *cls,
struct GNUNET_ATS_Session *session,
const struct GNUNET_TRANSPORT_SessionInfo *info);
/**
* Begin monitoring sessions of a plugin. There can only
* be one active monitor per plugin (i.e. if there are
* multiple monitors, the transport service needs to
* multiplex the generated events over all of them).
*
* @param cls closure of the plugin
* @param sic callback to invoke, NULL to disable monitor;
* plugin will being by iterating over all active
* sessions immediately and then enter monitor mode
* @param sic_cls closure for @a sic
*/
typedef void
(*GNUNET_TRANSPORT_SessionMonitorSetup) (void *cls,
GNUNET_TRANSPORT_SessionInfoCallback sic,
void *sic_cls);
/**
* Each plugin is required to return a pointer to a struct of this
* type as the return value from its entry point.
*/
struct GNUNET_TRANSPORT_PluginFunctions
{
/**
* Closure for all of the callbacks.
*/
void *cls;
/**
* Function that the transport service will use to transmit data to
* another peer. May be NULL for plugins that only support
* receiving data. After this call, the plugin call the specified
* continuation with success or error before notifying us about the
* target having disconnected.
*/
GNUNET_TRANSPORT_TransmitFunction send;
/**
* Function that can be used to force the plugin to disconnect from
* the given peer and cancel all previous transmissions (and their
* continuations).
*/
GNUNET_TRANSPORT_DisconnectPeerFunction disconnect_peer;
/**
* Function that can be used to force the plugin to disconnect from
* the given peer and cancel all previous transmissions (and their
* continuations).
*/
GNUNET_TRANSPORT_DisconnectSessionFunction disconnect_session;
/**
* Function that will be called whenever the transport service wants to
* notify the plugin that a session is still active and in use and
* therefore the session timeout for this session has to be updated
*/
GNUNET_TRANSPORT_UpdateSessionTimeout update_session_timeout;
/**
* Function that will be called whenever the transport service wants to
* notify the plugin that the inbound quota changed and that the plugin
* should update it's delay for the next receive value
*/
GNUNET_TRANSPORT_UpdateInboundDelay update_inbound_delay;
/**
* Function that is used to query keepalive factor.
* #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
* calculate the interval between keepalive packets.
*/
GNUNET_TRANSPORT_QueryKeepaliveFactorFunction query_keepalive_factor;
/**
* Function to pretty-print addresses.
*/
GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
/**
* Function that will be called to check if a binary address
* for this plugin is well-formed and corresponds to an
* address for THIS peer (as per our configuration). Naturally,
* if absolutely necessary, plugins can be a bit conservative in
* their answer, but in general plugins should make sure that the
* address does not redirect traffic to a 3rd party that might
* try to man-in-the-middle our traffic.
*/
GNUNET_TRANSPORT_CheckAddress check_address;
/**
* Function that will be called to convert a binary address
* to a string (numeric conversion only).
*/
GNUNET_TRANSPORT_AddressToString address_to_string;
/**
* Function that will be called to convert a string address
* to binary (numeric conversion only).
*/
GNUNET_TRANSPORT_StringToAddress string_to_address;
/**
* Function that will be called tell the plugin to create a session
* object.
*/
GNUNET_TRANSPORT_CreateSession get_session;
/**
* Function to obtain the network type for a session
*/
GNUNET_TRANSPORT_GetNetworkType get_network;
/**
* Function to obtain the network type for an address
*/
GNUNET_TRANSPORT_GetNetworkTypeForAddress get_network_for_address;
/**
* Function to monitor the sessions managed by the plugin.
*/
GNUNET_TRANSPORT_SessionMonitorSetup setup_monitor;
};
/*#ifndef PLUGIN_TRANSPORT_H*/
#endif
/** @} */ /* end of group */
/* end of gnunet_transport_plugin.h */