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).
58 * Every `struct Session` must begin with this header.
67 * Function that will be called whenever the plugin internally
68 * cleans up a session pointer and hence the service needs to
69 * discard all of those sessions as well. Plugins that do not
70 * use sessions can simply omit calling this function and always
71 * use NULL wherever a session pointer is needed. This function
72 * should be called BEFORE a potential "TransmitContinuation"
73 * from the "TransmitFunction".
76 * @param peer which peer was the session for
77 * @param session which session is being destroyed
80 (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
81 const struct GNUNET_HELLO_Address *address,
82 struct Session *session);
85 * Plugin tells transport service about a new inbound session
88 * @param address the address
89 * @param session the new session
90 * @param ats ats information
91 * @param ats_count number of @a ats information
94 (*GNUNET_TRANSPORT_SessionStart) (void *cls,
95 struct GNUNET_HELLO_Address *address,
96 struct Session *session,
97 const struct GNUNET_ATS_Information *ats,
101 * Function called by the transport for each received message.
102 * This function should also be called with "NULL" for the
103 * message to signal that the other peer disconnected.
106 * @param peer (claimed) identity of the other peer
107 * @param message the message, NULL if we only care about
108 * learning about the delay until we should receive again
109 * @param session identifier used for this session (NULL for plugins
110 * that do not offer bi-directional communication to the sender
111 * using the same "connection")
112 * @param sender_address binary address of the sender (if we established the
113 * connection or are otherwise sure of it; should be NULL
114 * for inbound TCP/UDP connections since it it not clear
115 * that we could establish ourselves a connection to that
116 * IP address and get the same system)
117 * @param sender_address_len number of bytes in @a sender_address
118 * @return how long the plugin should wait until receiving more data;
119 * returning #GNUNET_TIME_UNIT_FOREVER_REL means that the
120 * connection should be closed
122 typedef struct GNUNET_TIME_Relative
123 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
124 const struct GNUNET_HELLO_Address *address,
125 struct Session *session,
126 const struct GNUNET_MessageHeader *message);
130 * Function that will be called to figure if an address is an loopback,
131 * LAN, WAN etc. address
134 * @param addr binary address
135 * @param addrlen length of the @a addr
136 * @return ATS Information containing the network type
138 typedef struct GNUNET_ATS_Information
139 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
140 const struct sockaddr *addr,
145 * Function called when quality properties of an address change.
149 * @param address address
150 * @param address_len length of the @a address
151 * @param session session
152 * @param ats ATS information
153 * @param ats_count number entries in the @a ats array
156 (*GNUNET_TRANSPORT_UpdateAddressMetrics) (void *cls,
157 const struct GNUNET_HELLO_Address *address,
158 struct Session *session,
159 const struct GNUNET_ATS_Information *ats,
163 * Function that will be called for each address the transport
164 * is aware that it might be reachable under.
167 * @param add_remove should the address added (#GNUNET_YES) or removed (#GNUNET_NO) from the
168 * set of valid addresses?
169 * @param address the address to add or remove
172 (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
174 const struct GNUNET_HELLO_Address *address);
178 * Function that will be called whenever the plugin receives data over
179 * the network and wants to determine how long it should wait until
180 * the next time it reads from the given peer. Note that some plugins
181 * (such as UDP) may not be able to wait (for a particular peer), so
182 * the waiting part is optional. Plugins that can wait should call
183 * this function, sleep the given amount of time, and call it again
184 * (with zero bytes read) UNTIL it returns zero and only then read.
187 * @param peer which peer did we read data from
188 * @param amount_recved number of bytes read (can be zero)
189 * @return how long to wait until reading more from this peer
190 * (to enforce inbound quotas); returning #GNUNET_TIME_UNIT_FOREVER_REL
191 * means that the connection should be closed
193 typedef struct GNUNET_TIME_Relative
194 (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
195 const struct GNUNET_PeerIdentity *peer,
196 size_t amount_recved);
203 (*GNUNET_TRANSPORT_RegisterQuotaNotification) (void *cls,
204 const struct GNUNET_PeerIdentity *peer,
206 struct Session *session);
213 (*GNUNET_TRANSPORT_UnregisterQuotaNotification) (void *cls,
214 const struct GNUNET_PeerIdentity *peer,
216 struct Session *session);
219 * Function that returns a HELLO message.
221 * @return HELLO message (FIXME with what?)
223 typedef const struct GNUNET_MessageHeader *
224 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
228 * The transport service will pass a pointer to a struct
229 * of this type as the first and only argument to the
230 * entry point of each transport plugin.
232 struct GNUNET_TRANSPORT_PluginEnvironment
235 * Configuration to use.
237 const struct GNUNET_CONFIGURATION_Handle *cfg;
240 * Identity of this peer.
242 const struct GNUNET_PeerIdentity *my_identity;
245 * Closure for the various callbacks.
250 * Handle for reporting statistics.
252 struct GNUNET_STATISTICS_Handle *stats;
255 * Function that should be called by the transport plugin
256 * whenever a message is received. If this field is "NULL",
257 * the plugin should load in 'stub' mode and NOT fully
258 * initialize and instead only return an API with the
259 * @e address_pretty_printer, @e address_to_string and
260 * @e string_to_address functions.
262 GNUNET_TRANSPORT_PluginReceiveCallback receive;
265 * Function that returns our HELLO.
267 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
270 * Function that must be called by each plugin to notify the
271 * transport service about the addresses under which the transport
272 * provided by the plugin can be reached.
274 GNUNET_TRANSPORT_AddressNotification notify_address;
277 * Function that must be called by the plugin when a non-NULL
278 * session handle stops being valid (is destroyed).
280 GNUNET_TRANSPORT_SessionEnd session_end;
283 * Function called by the plugin when a new (incoming) session was created
284 * not explicitly created using the the get_session function
286 GNUNET_TRANSPORT_SessionStart session_start;
289 * Function that will be called to figure if an address is an loopback,
290 * LAN, WAN etc. address
292 GNUNET_TRANSPORT_AddressToType get_address_type;
295 * Function that will be called to figure if an address is an loopback,
296 * LAN, WAN etc. address
298 GNUNET_TRANSPORT_UpdateAddressMetrics update_address_metrics;
303 GNUNET_TRANSPORT_RegisterQuotaNotification register_quota_notification;
308 GNUNET_TRANSPORT_UnregisterQuotaNotification unregister_quota_notification;
311 * What is the maximum number of connections that this transport
312 * should allow? Transports that do not have sessions (such as
313 * UDP) can ignore this value.
315 uint32_t max_connections;
321 * Function called by the #GNUNET_TRANSPORT_TransmitFunction
322 * upon "completion". In the case that a peer disconnects,
323 * this function must be called for each pending request
324 * (with a 'failure' indication) AFTER notifying the service
325 * about the disconnect event (so that the service won't try
326 * to transmit more messages, believing the connection still
330 * @param target who was the recipient of the message?
331 * @param result #GNUNET_OK on success
332 * #GNUNET_SYSERR if the target disconnected;
333 * disconnect will ALSO be signalled using
334 * the ReceiveCallback.
335 * @param size_payload bytes of payload from transport service in message
336 * @param size_on_wire bytes required on wire for transmission,
337 * 0 if result == #GNUNET_SYSERR
340 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
341 const struct GNUNET_PeerIdentity *target,
344 size_t size_on_wire);
348 * The new send function with just the session and no address
350 * Function that can be used by the transport service to transmit
351 * a message using the plugin. Note that in the case of a
352 * peer disconnecting, the continuation MUST be called
353 * prior to the disconnect notification itself. This function
354 * will be called with this peer's HELLO message to initiate
355 * a fresh connection to another peer.
358 * @param session which session must be used
359 * @param msgbuf the message to transmit
360 * @param msgbuf_size number of bytes in @a msgbuf
361 * @param priority how important is the message (most plugins will
362 * ignore message priority and just FIFO)
363 * @param to how long to wait at most for the transmission (does not
364 * require plugins to discard the message after the timeout,
365 * just advisory for the desired delay; most plugins will ignore
367 * @param cont continuation to call once the message has
368 * been transmitted (or if the transport is ready
369 * for the next transmission call; or if the
370 * peer disconnected...); can be NULL
371 * @param cont_cls closure for @a cont
372 * @return number of bytes used (on the physical network, with overheads);
373 * -1 on hard errors (i.e. address invalid); 0 is a legal value
374 * and does NOT mean that the message was not transmitted (DV)
377 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
378 struct Session *session,
381 unsigned int priority,
382 struct GNUNET_TIME_Relative to,
383 GNUNET_TRANSPORT_TransmitContinuation cont,
388 * Function that can be called to force a disconnect from the
389 * specified neighbour for the given session only. . This should
390 * also cancel all previously scheduled transmissions for this
391 * session. Obviously the transmission may have been partially
392 * completed already, which is OK. The plugin is supposed to close
393 * the connection (if applicable).
395 * @param cls closure with the `struct Plugin`
396 * @param session session to destroy
397 * @return #GNUNET_OK on success
400 (*GNUNET_TRANSPORT_DisconnectSessionFunction) (void *cls,
401 struct Session *session);
405 * Function that is called to get the keepalive factor.
406 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
407 * calculate the interval between keepalive packets.
409 * @param cls closure with the `struct Plugin`
410 * @return keepalive factor
413 (*GNUNET_TRANSPORT_QueryKeepaliveFactorFunction) (void *cls);
417 * Function that can be called to force a disconnect from the
418 * specified neighbour. This should also cancel all previously
419 * scheduled transmissions. Obviously the transmission may have been
420 * partially completed already, which is OK. The plugin is supposed
421 * to close the connection (if applicable) and no longer call the
422 * transmit continuation(s).
425 * @param target peer for which the last transmission is
429 (*GNUNET_TRANSPORT_DisconnectPeerFunction) (void *cls,
430 const struct GNUNET_PeerIdentity *target);
434 * Function called by the pretty printer for the resolved address for
435 * each human-readable address obtained. The callback can be called
436 * several times. The last invocation must be with a @a address of
437 * NULL and a @a res of #GNUNET_OK. Thus, to indicate conversion
438 * errors, the callback might be called first with @a address NULL and
439 * @a res being #GNUNET_SYSERR. In that case, there must still be a
440 * subsequent call later with @a address NULL and @a res #GNUNET_OK.
443 * @param address one of the names for the host, NULL on last callback
444 * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on failure,
445 * #GNUNET_OK on last callback
448 (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
454 * Convert the transports address to a nice, human-readable
458 * @param type name of the transport that generated the address
459 * @param addr one of the addresses of the host, NULL for the last address
460 * the specific address format depends on the transport
461 * @param addrlen length of the @a addr
462 * @param numeric should (IP) addresses be displayed in numeric form?
463 * @param timeout after how long should we give up?
464 * @param asc function to call on each string
465 * @param asc_cls closure for @a asc
468 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
473 struct GNUNET_TIME_Relative timeout,
474 GNUNET_TRANSPORT_AddressStringCallback asc,
479 * Another peer has suggested an address for this peer and transport
480 * plugin. Check that this could be a valid address. This function
481 * is not expected to 'validate' the address in the sense of trying to
482 * connect to it but simply to see if the binary format is technically
483 * legal for establishing a connection to this peer (and make sure that
484 * the address really corresponds to our network connection/settings
485 * and not some potential man-in-the-middle).
487 * @param addr pointer to the address
488 * @param addrlen length of @a addr
489 * @return #GNUNET_OK if this is a plausible address for this peer
490 * and transport, #GNUNET_SYSERR if not
493 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
499 * Create a new session to transmit data to the target
500 * This session will used to send data to this peer and the plugin will
501 * notify us by calling the env->session_end function
503 * @param cls the plugin
504 * @param address the hello address
505 * @return the session if the address is valid, NULL otherwise
507 typedef struct Session *
508 (*GNUNET_TRANSPORT_CreateSession) (void *cls,
509 const struct GNUNET_HELLO_Address *address);
513 * Function that will be called whenever the transport service wants to
514 * notify the plugin that a session is still active and in use and
515 * therefore the session timeout for this session has to be updated
518 * @param peer which peer was the session for
519 * @param session which session is being updated
522 (*GNUNET_TRANSPORT_UpdateSessionTimeout) (void *cls,
523 const struct GNUNET_PeerIdentity *peer,
524 struct Session *session);
529 * Function that will be called whenever the transport service wants to
530 * notify the plugin that the inbound quota changed and that the plugin
531 * should update it's delay for the next receive value
534 * @param peer which peer was the session for
535 * @param session which session is being updated
536 * @param delay new delay to use for receiving
539 (*GNUNET_TRANSPORT_UpdateInboundDelay) (void *cls,
540 const struct GNUNET_PeerIdentity *peer,
541 struct Session *session,
542 struct GNUNET_TIME_Relative delay);
545 * Function called for a quick conversion of the binary address to
546 * a numeric address. Note that the caller must not free the
547 * address and that the next call to this function is allowed
548 * to override the address again.
551 * @param addr binary address
552 * @param addr_len length of the @a addr
553 * @return string representing the same address
556 (*GNUNET_TRANSPORT_AddressToString) (void *cls,
562 * Function called to convert a string address to
565 * @param cls closure (`struct Plugin*`)
566 * @param addr string address
567 * @param addrlen length of the @a addr including \0 termination
568 * @param buf location to store the buffer
569 * If the function returns #GNUNET_SYSERR, its contents are undefined.
570 * @param added length of created address
571 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
574 (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
582 * Function to obtain the network type for a session
584 * @param cls closure ('struct Plugin*')
585 * @param session the session
586 * @return the network type
588 typedef enum GNUNET_ATS_Network_Type
589 (*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
590 struct Session *session);
594 * Possible states of a session in a plugin.
596 enum GNUNET_TRANSPORT_SessionState
599 * Session is being torn down and about to disappear.
601 GNUNET_TRANSPORT_SS_DOWN,
604 * Initial session handshake is in progress.
606 GNUNET_TRANSPORT_SS_HANDSHAKE,
609 * Session is fully UP.
611 GNUNET_TRANSPORT_SS_UP
617 * Information about a plugin's session.
619 struct GNUNET_TRANSPORT_SessionInfo
623 * New state of the session.
625 enum GNUNET_TRANSPORT_SessionState state;
628 * #GNUNET_YES if this is an inbound connection,
629 * #GNUNET_NO if this is an outbound connection,
630 * #GNUNET_SYSERR if connections of this plugin
631 * are so fundamentally bidirectional
632 * that they have no 'initiator'
637 * Number of messages pending transmission for this session.
639 unsigned int num_msg_pending;
642 * Number of bytes pending transmission for this session.
644 unsigned int num_bytes_pending;
647 * Until when does this plugin refuse to receive to manage
648 * staying within the inbound quota? ZERO if receive is
651 struct GNUNET_TIME_Absolute receive_delay;
654 * At what time will this session timeout (unless activity
657 struct GNUNET_TIME_Absolute session_timeout;
660 * Address used by the session. Can be NULL if none is available.
662 const struct GNUNET_HELLO_Address *address;
667 * Function called by the plugin with information about the
668 * current sessions managed by the plugin (for monitoring).
671 * @param session session handle this information is about,
672 * NULL to indicate that we are "in sync" (initial
673 * iteration complete)
674 * @param info information about the state of the session,
675 * NULL if @a session is also NULL and we are
676 * merely signalling that the initial iteration is over
679 (*GNUNET_TRANSPORT_SessionInfoCallback) (void *cls,
680 struct Session *session,
681 const struct GNUNET_TRANSPORT_SessionInfo *info);
685 * Begin monitoring sessions of a plugin. There can only
686 * be one active monitor per plugin (i.e. if there are
687 * multiple monitors, the transport service needs to
688 * multiplex the generated events over all of them).
690 * @param cls closure of the plugin
691 * @param sic callback to invoke, NULL to disable monitor;
692 * plugin will being by iterating over all active
693 * sessions immediately and then enter monitor mode
694 * @param sic_cls closure for @a sic
697 (*GNUNET_TRANSPORT_SessionMonitorSetup) (void *cls,
698 GNUNET_TRANSPORT_SessionInfoCallback sic,
703 * Each plugin is required to return a pointer to a struct of this
704 * type as the return value from its entry point.
706 struct GNUNET_TRANSPORT_PluginFunctions
710 * Closure for all of the callbacks.
715 * Function that the transport service will use to transmit data to
716 * another peer. May be NULL for plugins that only support
717 * receiving data. After this call, the plugin call the specified
718 * continuation with success or error before notifying us about the
719 * target having disconnected.
721 GNUNET_TRANSPORT_TransmitFunction send;
724 * Function that can be used to force the plugin to disconnect from
725 * the given peer and cancel all previous transmissions (and their
728 GNUNET_TRANSPORT_DisconnectPeerFunction disconnect_peer;
731 * Function that can be used to force the plugin to disconnect from
732 * the given peer and cancel all previous transmissions (and their
735 GNUNET_TRANSPORT_DisconnectSessionFunction disconnect_session;
738 * Function that will be called whenever the transport service wants to
739 * notify the plugin that a session is still active and in use and
740 * therefore the session timeout for this session has to be updated
742 GNUNET_TRANSPORT_UpdateSessionTimeout update_session_timeout;
745 * Function that will be called whenever the transport service wants to
746 * notify the plugin that the inbound quota changed and that the plugin
747 * should update it's delay for the next receive value
749 GNUNET_TRANSPORT_UpdateInboundDelay update_inbound_delay;
752 * Function that is used to query keepalive factor.
753 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
754 * calculate the interval between keepalive packets.
756 GNUNET_TRANSPORT_QueryKeepaliveFactorFunction query_keepalive_factor;
759 * Function to pretty-print addresses.
761 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
764 * Function that will be called to check if a binary address
765 * for this plugin is well-formed and corresponds to an
766 * address for THIS peer (as per our configuration). Naturally,
767 * if absolutely necessary, plugins can be a bit conservative in
768 * their answer, but in general plugins should make sure that the
769 * address does not redirect traffic to a 3rd party that might
770 * try to man-in-the-middle our traffic.
772 GNUNET_TRANSPORT_CheckAddress check_address;
775 * Function that will be called to convert a binary address
776 * to a string (numeric conversion only).
778 GNUNET_TRANSPORT_AddressToString address_to_string;
781 * Function that will be called to convert a string address
782 * to binary (numeric conversion only).
784 GNUNET_TRANSPORT_StringToAddress string_to_address;
787 * Function that will be called tell the plugin to create a session
790 GNUNET_TRANSPORT_CreateSession get_session;
793 * Function to obtain the network type for a session
795 GNUNET_TRANSPORT_GetNetworkType get_network;
798 * Function to monitor the sessions managed by the plugin.
800 GNUNET_TRANSPORT_SessionMonitorSetup setup_monitor;
804 /*#ifndef PLUGIN_TRANSPORT_H*/
806 /* end of gnunet_transport_plugin.h */