2 This file is part of GNUnet
3 (C) 2009-2014 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_transport_plugin.h
23 * @brief API for the transport services. This header
24 * specifies the struct that is given to the plugin's entry
25 * method and the other struct that must be returned.
26 * Note that the destructors of transport plugins will
27 * be given the value returned by the constructor
28 * and is expected to return a NULL pointer.
29 * @author Christian Grothoff
31 #ifndef PLUGIN_TRANSPORT_H
32 #define PLUGIN_TRANSPORT_H
34 #include "gnunet_configuration_lib.h"
35 #include "gnunet_scheduler_lib.h"
36 #include "gnunet_statistics_service.h"
37 #include "gnunet_transport_service.h"
38 #include "gnunet_ats_service.h"
40 #define TRANSPORT_SESSION_INBOUND_STRING "<inbound>"
43 * Opaque pointer that plugins can use to distinguish specific
44 * connections to a given peer. Typically used by stateful plugins to
45 * allow the service to refer to specific streams instead of a more
46 * general notion of "some connection" to the given peer. This is
47 * useful since sometimes (i.e. for inbound TCP connections) a
48 * connection may not have an address that can be used for meaningful
49 * distinction between sessions to the same peer.
51 * Each 'struct Session' MUST start with the 'struct GNUNET_PeerIdentity'
52 * of the peer the session is for (which will be used for some error
53 * checking by the ATS code).
59 * Function that will be called whenever the plugin internally
60 * cleans up a session pointer and hence the service needs to
61 * discard all of those sessions as well. Plugins that do not
62 * use sessions can simply omit calling this function and always
63 * use NULL wherever a session pointer is needed. This function
64 * should be called BEFORE a potential "TransmitContinuation"
65 * from the "TransmitFunction".
68 * @param peer which peer was the session for
69 * @param session which session is being destroyed
72 (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
73 const struct GNUNET_HELLO_Address *address,
74 struct Session *session);
78 * Plugin tells transport service about a new inbound session
81 * @param address the address
82 * @param session the new session
83 * @param ats ats information
84 * @param ats_count number of @a ats information
87 (*GNUNET_TRANSPORT_SessionStart) (void *cls,
88 struct GNUNET_HELLO_Address *address,
89 struct Session *session,
90 const struct GNUNET_ATS_Information *ats,
94 * Function called by the transport for each received message.
95 * This function should also be called with "NULL" for the
96 * message to signal that the other peer disconnected.
99 * @param peer (claimed) identity of the other peer
100 * @param message the message, NULL if we only care about
101 * learning about the delay until we should receive again
102 * @param session identifier used for this session (NULL for plugins
103 * that do not offer bi-directional communication to the sender
104 * using the same "connection")
105 * @param sender_address binary address of the sender (if we established the
106 * connection or are otherwise sure of it; should be NULL
107 * for inbound TCP/UDP connections since it it not clear
108 * that we could establish ourselves a connection to that
109 * IP address and get the same system)
110 * @param sender_address_len number of bytes in @a sender_address
111 * @return how long the plugin should wait until receiving more data;
112 * returning #GNUNET_TIME_UNIT_FOREVER_REL means that the
113 * connection should be closed
115 typedef struct GNUNET_TIME_Relative
116 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
117 const struct GNUNET_HELLO_Address *address,
118 struct Session *session,
119 const struct GNUNET_MessageHeader *message);
123 * Function that will be called to figure if an address is an loopback,
124 * LAN, WAN etc. address
127 * @param addr binary address
128 * @param addrlen length of the @a addr
129 * @return ATS Information containing the network type
131 typedef struct GNUNET_ATS_Information
132 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
133 const struct sockaddr *addr,
138 * Function called when quality properties of an address change.
142 * @param address address
143 * @param address_len length of the @a address
144 * @param session session
145 * @param ats ATS information
146 * @param ats_count number entries in the @a ats array
149 (*GNUNET_TRANSPORT_UpdateAddressMetrics) (void *cls,
150 const struct GNUNET_HELLO_Address *address,
151 struct Session *session,
152 const struct GNUNET_ATS_Information *ats,
156 * Function that will be called for each address the transport
157 * is aware that it might be reachable under.
160 * @param add_remove should the address added (#GNUNET_YES) or removed (#GNUNET_NO) from the
161 * set of valid addresses?
162 * @param address the address to add or remove
165 (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
167 const struct GNUNET_HELLO_Address *address);
171 * Function that will be called whenever the plugin receives data over
172 * the network and wants to determine how long it should wait until
173 * the next time it reads from the given peer. Note that some plugins
174 * (such as UDP) may not be able to wait (for a particular peer), so
175 * the waiting part is optional. Plugins that can wait should call
176 * this function, sleep the given amount of time, and call it again
177 * (with zero bytes read) UNTIL it returns zero and only then read.
180 * @param peer which peer did we read data from
181 * @param amount_recved number of bytes read (can be zero)
182 * @return how long to wait until reading more from this peer
183 * (to enforce inbound quotas); returning #GNUNET_TIME_UNIT_FOREVER_REL
184 * means that the connection should be closed
186 typedef struct GNUNET_TIME_Relative
187 (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
188 const struct GNUNET_PeerIdentity *peer,
189 size_t amount_recved);
193 * Function to be called by the plugin to be notified about changes to the quota
194 * for a specific peer, plugin and session
197 * @param peer the peer to be notified about
198 * @param plugin the plugin to be notified about
199 * @param session the session for include in the notification
203 (*GNUNET_TRANSPORT_RegisterQuotaNotification) (void *cls,
204 const struct GNUNET_PeerIdentity *peer,
206 struct Session *session);
210 * Function to be called by the plugin to stop notification about changes to the quota
211 * for a specific peer, plugin and session
214 * @param peer the peer to be notified about
215 * @param plugin the plugin to be notified about
216 * @param session the session for include in the notification
219 (*GNUNET_TRANSPORT_UnregisterQuotaNotification) (void *cls,
220 const struct GNUNET_PeerIdentity *peer,
222 struct Session *session);
225 * Function that returns a HELLO message.
227 * @return HELLO message (FIXME with what?)
229 typedef const struct GNUNET_MessageHeader *
230 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
234 * The transport service will pass a pointer to a struct
235 * of this type as the first and only argument to the
236 * entry point of each transport plugin.
238 struct GNUNET_TRANSPORT_PluginEnvironment
241 * Configuration to use.
243 const struct GNUNET_CONFIGURATION_Handle *cfg;
246 * Identity of this peer.
248 const struct GNUNET_PeerIdentity *my_identity;
251 * Closure for the various callbacks.
256 * Handle for reporting statistics.
258 struct GNUNET_STATISTICS_Handle *stats;
261 * Function that should be called by the transport plugin
262 * whenever a message is received. If this field is "NULL",
263 * the plugin should load in 'stub' mode and NOT fully
264 * initialize and instead only return an API with the
265 * @e address_pretty_printer, @e address_to_string and
266 * @e string_to_address functions.
268 GNUNET_TRANSPORT_PluginReceiveCallback receive;
271 * Function that returns our HELLO.
273 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
276 * Function that must be called by each plugin to notify the
277 * transport service about the addresses under which the transport
278 * provided by the plugin can be reached.
280 GNUNET_TRANSPORT_AddressNotification notify_address;
283 * Function that must be called by the plugin when a non-NULL
284 * session handle stops being valid (is destroyed).
286 GNUNET_TRANSPORT_SessionEnd session_end;
289 * Function called by the plugin when a new (incoming) session was created
290 * not explicitly created using the the get_session function
292 GNUNET_TRANSPORT_SessionStart session_start;
295 * Function that will be called to figure if an address is an loopback,
296 * LAN, WAN etc. address
298 GNUNET_TRANSPORT_AddressToType get_address_type;
301 * Function that will be called to figure if an address is an loopback,
302 * LAN, WAN etc. address
304 GNUNET_TRANSPORT_UpdateAddressMetrics update_address_metrics;
309 GNUNET_TRANSPORT_RegisterQuotaNotification register_quota_notification;
314 GNUNET_TRANSPORT_UnregisterQuotaNotification unregister_quota_notification;
317 * What is the maximum number of connections that this transport
318 * should allow? Transports that do not have sessions (such as
319 * UDP) can ignore this value.
321 uint32_t max_connections;
327 * Function called by the #GNUNET_TRANSPORT_TransmitFunction
328 * upon "completion". In the case that a peer disconnects,
329 * this function must be called for each pending request
330 * (with a 'failure' indication) AFTER notifying the service
331 * about the disconnect event (so that the service won't try
332 * to transmit more messages, believing the connection still
336 * @param target who was the recipient of the message?
337 * @param result #GNUNET_OK on success
338 * #GNUNET_SYSERR if the target disconnected;
339 * disconnect will ALSO be signalled using
340 * the ReceiveCallback.
341 * @param size_payload bytes of payload from transport service in message
342 * @param size_on_wire bytes required on wire for transmission,
343 * 0 if result == #GNUNET_SYSERR
346 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
347 const struct GNUNET_PeerIdentity *target,
350 size_t size_on_wire);
354 * The new send function with just the session and no address
356 * Function that can be used by the transport service to transmit
357 * a message using the plugin. Note that in the case of a
358 * peer disconnecting, the continuation MUST be called
359 * prior to the disconnect notification itself. This function
360 * will be called with this peer's HELLO message to initiate
361 * a fresh connection to another peer.
364 * @param session which session must be used
365 * @param msgbuf the message to transmit
366 * @param msgbuf_size number of bytes in @a msgbuf
367 * @param priority how important is the message (most plugins will
368 * ignore message priority and just FIFO)
369 * @param to how long to wait at most for the transmission (does not
370 * require plugins to discard the message after the timeout,
371 * just advisory for the desired delay; most plugins will ignore
373 * @param cont continuation to call once the message has
374 * been transmitted (or if the transport is ready
375 * for the next transmission call; or if the
376 * peer disconnected...); can be NULL
377 * @param cont_cls closure for @a cont
378 * @return number of bytes used (on the physical network, with overheads);
379 * -1 on hard errors (i.e. address invalid); 0 is a legal value
380 * and does NOT mean that the message was not transmitted (DV)
383 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
384 struct Session *session,
387 unsigned int priority,
388 struct GNUNET_TIME_Relative to,
389 GNUNET_TRANSPORT_TransmitContinuation cont,
394 * Function that can be called to force a disconnect from the
395 * specified neighbour for the given session only. . This should
396 * also cancel all previously scheduled transmissions for this
397 * session. Obviously the transmission may have been partially
398 * completed already, which is OK. The plugin is supposed to close
399 * the connection (if applicable).
401 * @param cls closure with the `struct Plugin`
402 * @param session session to destroy
403 * @return #GNUNET_OK on success
406 (*GNUNET_TRANSPORT_DisconnectSessionFunction) (void *cls,
407 struct Session *session);
411 * Function that is called to get the keepalive factor.
412 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
413 * calculate the interval between keepalive packets.
415 * @param cls closure with the `struct Plugin`
416 * @return keepalive factor
419 (*GNUNET_TRANSPORT_QueryKeepaliveFactorFunction) (void *cls);
423 * Function that can be called to force a disconnect from the
424 * specified neighbour. This should also cancel all previously
425 * scheduled transmissions. Obviously the transmission may have been
426 * partially completed already, which is OK. The plugin is supposed
427 * to close the connection (if applicable) and no longer call the
428 * transmit continuation(s).
431 * @param target peer for which the last transmission is
435 (*GNUNET_TRANSPORT_DisconnectPeerFunction) (void *cls,
436 const struct GNUNET_PeerIdentity *target);
440 * Function called by the pretty printer for the resolved address for
441 * each human-readable address obtained. The callback can be called
442 * several times. The last invocation must be with a @a address of
443 * NULL and a @a res of #GNUNET_OK. Thus, to indicate conversion
444 * errors, the callback might be called first with @a address NULL and
445 * @a res being #GNUNET_SYSERR. In that case, there must still be a
446 * subsequent call later with @a address NULL and @a res #GNUNET_OK.
449 * @param address one of the names for the host, NULL on last callback
450 * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on failure,
451 * #GNUNET_OK on last callback
454 (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
460 * Convert the transports address to a nice, human-readable
464 * @param type name of the transport that generated the address
465 * @param addr one of the addresses of the host, NULL for the last address
466 * the specific address format depends on the transport
467 * @param addrlen length of the @a addr
468 * @param numeric should (IP) addresses be displayed in numeric form?
469 * @param timeout after how long should we give up?
470 * @param asc function to call on each string
471 * @param asc_cls closure for @a asc
474 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
479 struct GNUNET_TIME_Relative timeout,
480 GNUNET_TRANSPORT_AddressStringCallback asc,
485 * Another peer has suggested an address for this peer and transport
486 * plugin. Check that this could be a valid address. This function
487 * is not expected to 'validate' the address in the sense of trying to
488 * connect to it but simply to see if the binary format is technically
489 * legal for establishing a connection to this peer (and make sure that
490 * the address really corresponds to our network connection/settings
491 * and not some potential man-in-the-middle).
493 * @param addr pointer to the address
494 * @param addrlen length of @a addr
495 * @return #GNUNET_OK if this is a plausible address for this peer
496 * and transport, #GNUNET_SYSERR if not
499 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
505 * Create a new session to transmit data to the target
506 * This session will used to send data to this peer and the plugin will
507 * notify us by calling the env->session_end function
509 * @param cls the plugin
510 * @param address the hello address
511 * @return the session if the address is valid, NULL otherwise
513 typedef struct Session *
514 (*GNUNET_TRANSPORT_CreateSession) (void *cls,
515 const struct GNUNET_HELLO_Address *address);
519 * Function that will be called whenever the transport service wants to
520 * notify the plugin that a session is still active and in use and
521 * therefore the session timeout for this session has to be updated
524 * @param peer which peer was the session for
525 * @param session which session is being updated
528 (*GNUNET_TRANSPORT_UpdateSessionTimeout) (void *cls,
529 const struct GNUNET_PeerIdentity *peer,
530 struct Session *session);
535 * Function that will be called whenever the transport service wants to
536 * notify the plugin that the inbound quota changed and that the plugin
537 * should update it's delay for the next receive value
540 * @param peer which peer was the session for
541 * @param session which session is being updated
542 * @param delay new delay to use for receiving
545 (*GNUNET_TRANSPORT_UpdateInboundDelay) (void *cls,
546 const struct GNUNET_PeerIdentity *peer,
547 struct Session *session,
548 struct GNUNET_TIME_Relative delay);
551 * Function called for a quick conversion of the binary address to
552 * a numeric address. Note that the caller must not free the
553 * address and that the next call to this function is allowed
554 * to override the address again.
557 * @param addr binary address
558 * @param addr_len length of the @a addr
559 * @return string representing the same address
562 (*GNUNET_TRANSPORT_AddressToString) (void *cls,
568 * Function called to convert a string address to
571 * @param cls closure (`struct Plugin*`)
572 * @param addr string address
573 * @param addrlen length of the @a addr including \0 termination
574 * @param buf location to store the buffer
575 * If the function returns #GNUNET_SYSERR, its contents are undefined.
576 * @param added length of created address
577 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
580 (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
588 * Function to obtain the network type for a session
590 * @param cls closure ('struct Plugin*')
591 * @param session the session
592 * @return the network type
594 typedef enum GNUNET_ATS_Network_Type
595 (*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
596 struct Session *session);
600 * Function called by the plugin with information about the
601 * current sessions managed by the plugin (for monitoring).
604 * @param session session handle this information is about,
605 * NULL to indicate that we are "in sync" (initial
606 * iteration complete)
607 * @param info information about the state of the session,
608 * NULL if @a session is also NULL and we are
609 * merely signalling that the initial iteration is over
612 (*GNUNET_TRANSPORT_SessionInfoCallback) (void *cls,
613 struct Session *session,
614 const struct GNUNET_TRANSPORT_SessionInfo *info);
618 * Begin monitoring sessions of a plugin. There can only
619 * be one active monitor per plugin (i.e. if there are
620 * multiple monitors, the transport service needs to
621 * multiplex the generated events over all of them).
623 * @param cls closure of the plugin
624 * @param sic callback to invoke, NULL to disable monitor;
625 * plugin will being by iterating over all active
626 * sessions immediately and then enter monitor mode
627 * @param sic_cls closure for @a sic
630 (*GNUNET_TRANSPORT_SessionMonitorSetup) (void *cls,
631 GNUNET_TRANSPORT_SessionInfoCallback sic,
636 * Each plugin is required to return a pointer to a struct of this
637 * type as the return value from its entry point.
639 struct GNUNET_TRANSPORT_PluginFunctions
643 * Closure for all of the callbacks.
648 * Function that the transport service will use to transmit data to
649 * another peer. May be NULL for plugins that only support
650 * receiving data. After this call, the plugin call the specified
651 * continuation with success or error before notifying us about the
652 * target having disconnected.
654 GNUNET_TRANSPORT_TransmitFunction send;
657 * Function that can be used to force the plugin to disconnect from
658 * the given peer and cancel all previous transmissions (and their
661 GNUNET_TRANSPORT_DisconnectPeerFunction disconnect_peer;
664 * Function that can be used to force the plugin to disconnect from
665 * the given peer and cancel all previous transmissions (and their
668 GNUNET_TRANSPORT_DisconnectSessionFunction disconnect_session;
671 * Function that will be called whenever the transport service wants to
672 * notify the plugin that a session is still active and in use and
673 * therefore the session timeout for this session has to be updated
675 GNUNET_TRANSPORT_UpdateSessionTimeout update_session_timeout;
678 * Function that will be called whenever the transport service wants to
679 * notify the plugin that the inbound quota changed and that the plugin
680 * should update it's delay for the next receive value
682 GNUNET_TRANSPORT_UpdateInboundDelay update_inbound_delay;
685 * Function that is used to query keepalive factor.
686 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
687 * calculate the interval between keepalive packets.
689 GNUNET_TRANSPORT_QueryKeepaliveFactorFunction query_keepalive_factor;
692 * Function to pretty-print addresses.
694 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
697 * Function that will be called to check if a binary address
698 * for this plugin is well-formed and corresponds to an
699 * address for THIS peer (as per our configuration). Naturally,
700 * if absolutely necessary, plugins can be a bit conservative in
701 * their answer, but in general plugins should make sure that the
702 * address does not redirect traffic to a 3rd party that might
703 * try to man-in-the-middle our traffic.
705 GNUNET_TRANSPORT_CheckAddress check_address;
708 * Function that will be called to convert a binary address
709 * to a string (numeric conversion only).
711 GNUNET_TRANSPORT_AddressToString address_to_string;
714 * Function that will be called to convert a string address
715 * to binary (numeric conversion only).
717 GNUNET_TRANSPORT_StringToAddress string_to_address;
720 * Function that will be called tell the plugin to create a session
723 GNUNET_TRANSPORT_CreateSession get_session;
726 * Function to obtain the network type for a session
728 GNUNET_TRANSPORT_GetNetworkType get_network;
731 * Function to monitor the sessions managed by the plugin.
733 GNUNET_TRANSPORT_SessionMonitorSetup setup_monitor;
737 /*#ifndef PLUGIN_TRANSPORT_H*/
739 /* end of gnunet_transport_plugin.h */