2 This file is part of GNUnet
3 Copyright (C) 2009-2014 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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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 net network information
86 (*GNUNET_TRANSPORT_SessionStart) (void *cls,
87 const struct GNUNET_HELLO_Address *address,
88 struct Session *session,
89 enum GNUNET_ATS_Network_Type net);
93 * Function called by the transport for each received message.
94 * This function should also be called with "NULL" for the
95 * message to signal that the other peer disconnected.
98 * @param peer (claimed) identity of the other peer
99 * @param message the message, NULL if we only care about
100 * learning about the delay until we should receive again
101 * @param session identifier used for this session (NULL for plugins
102 * that do not offer bi-directional communication to the sender
103 * using the same "connection")
104 * @param sender_address binary address of the sender (if we established the
105 * connection or are otherwise sure of it; should be NULL
106 * for inbound TCP/UDP connections since it it not clear
107 * that we could establish ourselves a connection to that
108 * IP address and get the same system)
109 * @param sender_address_len number of bytes in @a sender_address
110 * @return how long the plugin should wait until receiving more data;
111 * returning #GNUNET_TIME_UNIT_FOREVER_REL means that the
112 * connection should be closed
114 typedef struct GNUNET_TIME_Relative
115 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
116 const struct GNUNET_HELLO_Address *address,
117 struct Session *session,
118 const struct GNUNET_MessageHeader *message);
122 * Function that can be called by plugins to figure if an address is
123 * an loopback, LAN or WAN address. Ultimately invokes
124 * #GNUNET_ATS_address_get_type().
127 * @param addr binary address
128 * @param addrlen length of the @a addr
129 * @return type of the network the address belongs to
131 typedef enum GNUNET_ATS_Network_Type
132 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
133 const struct sockaddr *addr,
138 * Function called when distance of an address changes.
142 * @param distance new distance
145 (*GNUNET_TRANSPORT_UpdateAddressDistance) (void *cls,
146 const struct GNUNET_HELLO_Address *address,
151 * Function that will be called for each address the transport
152 * is aware that it might be reachable under.
155 * @param add_remove should the address added (#GNUNET_YES) or removed (#GNUNET_NO) from the
156 * set of valid addresses?
157 * @param address the address to add or remove
160 (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
162 const struct GNUNET_HELLO_Address *address);
166 * Function that will be called whenever the plugin receives data over
167 * the network and wants to determine how long it should wait until
168 * the next time it reads from the given peer. Note that some plugins
169 * (such as UDP) may not be able to wait (for a particular peer), so
170 * the waiting part is optional. Plugins that can wait should call
171 * this function, sleep the given amount of time, and call it again
172 * (with zero bytes read) UNTIL it returns zero and only then read.
175 * @param peer which peer did we read data from
176 * @param amount_recved number of bytes read (can be zero)
177 * @return how long to wait until reading more from this peer
178 * (to enforce inbound quotas); returning #GNUNET_TIME_UNIT_FOREVER_REL
179 * means that the connection should be closed
181 typedef struct GNUNET_TIME_Relative
182 (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
183 const struct GNUNET_PeerIdentity *peer,
184 size_t amount_recved);
188 * Function that returns a HELLO message.
190 * @return HELLO message (FIXME with what?)
192 typedef const struct GNUNET_MessageHeader *
193 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
197 * The transport service will pass a pointer to a struct
198 * of this type as the first and only argument to the
199 * entry point of each transport plugin.
201 struct GNUNET_TRANSPORT_PluginEnvironment
204 * Configuration to use.
206 const struct GNUNET_CONFIGURATION_Handle *cfg;
209 * Identity of this peer.
211 const struct GNUNET_PeerIdentity *my_identity;
214 * Closure for the various callbacks.
219 * Handle for reporting statistics.
221 struct GNUNET_STATISTICS_Handle *stats;
224 * Function that should be called by the transport plugin
225 * whenever a message is received. If this field is "NULL",
226 * the plugin should load in 'stub' mode and NOT fully
227 * initialize and instead only return an API with the
228 * @e address_pretty_printer, @e address_to_string and
229 * @e string_to_address functions.
231 GNUNET_TRANSPORT_PluginReceiveCallback receive;
234 * Function that returns our HELLO.
236 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
239 * Function that must be called by each plugin to notify the
240 * transport service about the addresses under which the transport
241 * provided by the plugin can be reached.
243 GNUNET_TRANSPORT_AddressNotification notify_address;
246 * Function that must be called by the plugin when a non-NULL
247 * session handle stops being valid (is destroyed).
249 GNUNET_TRANSPORT_SessionEnd session_end;
252 * Function called by the plugin when a new (incoming) session was created
253 * not explicitly created using the the get_session function
255 GNUNET_TRANSPORT_SessionStart session_start;
258 * Function that will be called to figure if an address is an loopback,
259 * LAN, WAN etc. address
261 GNUNET_TRANSPORT_AddressToType get_address_type;
264 * Function that will be called by DV to update distance for
267 GNUNET_TRANSPORT_UpdateAddressDistance update_address_distance;
270 * What is the maximum number of connections that this transport
271 * should allow? Transports that do not have sessions (such as
272 * UDP) can ignore this value.
274 uint32_t max_connections;
280 * Function called by the #GNUNET_TRANSPORT_TransmitFunction
281 * upon "completion". In the case that a peer disconnects,
282 * this function must be called for each pending request
283 * (with a 'failure' indication) AFTER notifying the service
284 * about the disconnect event (so that the service won't try
285 * to transmit more messages, believing the connection still
289 * @param target who was the recipient of the message?
290 * @param result #GNUNET_OK on success
291 * #GNUNET_SYSERR if the target disconnected;
292 * disconnect will ALSO be signalled using
293 * the ReceiveCallback.
294 * @param size_payload bytes of payload from transport service in message
295 * @param size_on_wire bytes required on wire for transmission,
296 * 0 if result == #GNUNET_SYSERR
299 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
300 const struct GNUNET_PeerIdentity *target,
303 size_t size_on_wire);
307 * The new send function with just the session and no address
309 * Function that can be used by the transport service to transmit
310 * a message using the plugin. Note that in the case of a
311 * peer disconnecting, the continuation MUST be called
312 * prior to the disconnect notification itself. This function
313 * will be called with this peer's HELLO message to initiate
314 * a fresh connection to another peer.
317 * @param session which session must be used
318 * @param msgbuf the message to transmit
319 * @param msgbuf_size number of bytes in @a msgbuf
320 * @param priority how important is the message (most plugins will
321 * ignore message priority and just FIFO)
322 * @param to how long to wait at most for the transmission (does not
323 * require plugins to discard the message after the timeout,
324 * just advisory for the desired delay; most plugins will ignore
326 * @param cont continuation to call once the message has
327 * been transmitted (or if the transport is ready
328 * for the next transmission call; or if the
329 * peer disconnected...); can be NULL
330 * @param cont_cls closure for @a cont
331 * @return number of bytes used (on the physical network, with overheads);
332 * -1 on hard errors (i.e. address invalid); 0 is a legal value
333 * and does NOT mean that the message was not transmitted (DV)
336 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
337 struct Session *session,
340 unsigned int priority,
341 struct GNUNET_TIME_Relative to,
342 GNUNET_TRANSPORT_TransmitContinuation cont,
347 * Function that can be called to force a disconnect from the
348 * specified neighbour for the given session only. . This should
349 * also cancel all previously scheduled transmissions for this
350 * session. Obviously the transmission may have been partially
351 * completed already, which is OK. The plugin is supposed to close
352 * the connection (if applicable).
354 * @param cls closure with the `struct Plugin`
355 * @param session session to destroy
356 * @return #GNUNET_OK on success
359 (*GNUNET_TRANSPORT_DisconnectSessionFunction) (void *cls,
360 struct Session *session);
364 * Function that is called to get the keepalive factor.
365 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
366 * calculate the interval between keepalive packets.
368 * @param cls closure with the `struct Plugin`
369 * @return keepalive factor
372 (*GNUNET_TRANSPORT_QueryKeepaliveFactorFunction) (void *cls);
376 * Function that can be called to force a disconnect from the
377 * specified neighbour. This should also cancel all previously
378 * scheduled transmissions. Obviously the transmission may have been
379 * partially completed already, which is OK. The plugin is supposed
380 * to close the connection (if applicable) and no longer call the
381 * transmit continuation(s).
384 * @param target peer for which the last transmission is
388 (*GNUNET_TRANSPORT_DisconnectPeerFunction) (void *cls,
389 const struct GNUNET_PeerIdentity *target);
393 * Function called by the pretty printer for the resolved address for
394 * each human-readable address obtained. The callback can be called
395 * several times. The last invocation must be with a @a address of
396 * NULL and a @a res of #GNUNET_OK. Thus, to indicate conversion
397 * errors, the callback might be called first with @a address NULL and
398 * @a res being #GNUNET_SYSERR. In that case, there must still be a
399 * subsequent call later with @a address NULL and @a res #GNUNET_OK.
402 * @param address one of the names for the host, NULL on last callback
403 * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on failure,
404 * #GNUNET_OK on last callback
407 (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
413 * Convert the transports address to a nice, human-readable
417 * @param type name of the transport that generated the address
418 * @param addr one of the addresses of the host, NULL for the last address
419 * the specific address format depends on the transport
420 * @param addrlen length of the @a addr
421 * @param numeric should (IP) addresses be displayed in numeric form?
422 * @param timeout after how long should we give up?
423 * @param asc function to call on each string
424 * @param asc_cls closure for @a asc
427 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
432 struct GNUNET_TIME_Relative timeout,
433 GNUNET_TRANSPORT_AddressStringCallback asc,
438 * Another peer has suggested an address for this peer and transport
439 * plugin. Check that this could be a valid address. This function
440 * is not expected to 'validate' the address in the sense of trying to
441 * connect to it but simply to see if the binary format is technically
442 * legal for establishing a connection to this peer (and make sure that
443 * the address really corresponds to our network connection/settings
444 * and not some potential man-in-the-middle).
446 * @param addr pointer to the address
447 * @param addrlen length of @a addr
448 * @return #GNUNET_OK if this is a plausible address for this peer
449 * and transport, #GNUNET_SYSERR if not
452 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
458 * Create a new session to transmit data to the target
459 * This session will used to send data to this peer and the plugin will
460 * notify us by calling the env->session_end function
462 * @param cls the plugin
463 * @param address the hello address
464 * @return the session if the address is valid, NULL otherwise
466 typedef struct Session *
467 (*GNUNET_TRANSPORT_CreateSession) (void *cls,
468 const struct GNUNET_HELLO_Address *address);
472 * Function that will be called whenever the transport service wants to
473 * notify the plugin that a session is still active and in use and
474 * therefore the session timeout for this session has to be updated
477 * @param peer which peer was the session for
478 * @param session which session is being updated
481 (*GNUNET_TRANSPORT_UpdateSessionTimeout) (void *cls,
482 const struct GNUNET_PeerIdentity *peer,
483 struct Session *session);
487 * Function that will be called whenever the transport service wants to
488 * notify the plugin that the inbound quota changed and that the plugin
489 * should update it's delay for the next receive value
492 * @param peer which peer was the session for
493 * @param session which session is being updated
494 * @param delay new delay to use for receiving
497 (*GNUNET_TRANSPORT_UpdateInboundDelay) (void *cls,
498 const struct GNUNET_PeerIdentity *peer,
499 struct Session *session,
500 struct GNUNET_TIME_Relative delay);
503 * Function called for a quick conversion of the binary address to
504 * a numeric address. Note that the caller must not free the
505 * address and that the next call to this function is allowed
506 * to override the address again.
509 * @param addr binary address
510 * @param addr_len length of the @a addr
511 * @return string representing the same address
514 (*GNUNET_TRANSPORT_AddressToString) (void *cls,
520 * Function called to convert a string address to
523 * @param cls closure (`struct Plugin*`)
524 * @param addr string address
525 * @param addrlen length of the @a addr including \0 termination
526 * @param buf location to store the buffer
527 * If the function returns #GNUNET_SYSERR, its contents are undefined.
528 * @param added length of created address
529 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
532 (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
540 * Function to obtain the network type for a session
542 * @param cls closure (`struct Plugin *`)
543 * @param session the session
544 * @return the network type
546 typedef enum GNUNET_ATS_Network_Type
547 (*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
548 struct Session *session);
552 * Function called by the plugin with information about the
553 * current sessions managed by the plugin (for monitoring).
556 * @param session session handle this information is about,
557 * NULL to indicate that we are "in sync" (initial
558 * iteration complete)
559 * @param info information about the state of the session,
560 * NULL if @a session is also NULL and we are
561 * merely signalling that the initial iteration is over
564 (*GNUNET_TRANSPORT_SessionInfoCallback) (void *cls,
565 struct Session *session,
566 const struct GNUNET_TRANSPORT_SessionInfo *info);
570 * Begin monitoring sessions of a plugin. There can only
571 * be one active monitor per plugin (i.e. if there are
572 * multiple monitors, the transport service needs to
573 * multiplex the generated events over all of them).
575 * @param cls closure of the plugin
576 * @param sic callback to invoke, NULL to disable monitor;
577 * plugin will being by iterating over all active
578 * sessions immediately and then enter monitor mode
579 * @param sic_cls closure for @a sic
582 (*GNUNET_TRANSPORT_SessionMonitorSetup) (void *cls,
583 GNUNET_TRANSPORT_SessionInfoCallback sic,
588 * Each plugin is required to return a pointer to a struct of this
589 * type as the return value from its entry point.
591 struct GNUNET_TRANSPORT_PluginFunctions
595 * Closure for all of the callbacks.
600 * Function that the transport service will use to transmit data to
601 * another peer. May be NULL for plugins that only support
602 * receiving data. After this call, the plugin call the specified
603 * continuation with success or error before notifying us about the
604 * target having disconnected.
606 GNUNET_TRANSPORT_TransmitFunction send;
609 * Function that can be used to force the plugin to disconnect from
610 * the given peer and cancel all previous transmissions (and their
613 GNUNET_TRANSPORT_DisconnectPeerFunction disconnect_peer;
616 * Function that can be used to force the plugin to disconnect from
617 * the given peer and cancel all previous transmissions (and their
620 GNUNET_TRANSPORT_DisconnectSessionFunction disconnect_session;
623 * Function that will be called whenever the transport service wants to
624 * notify the plugin that a session is still active and in use and
625 * therefore the session timeout for this session has to be updated
627 GNUNET_TRANSPORT_UpdateSessionTimeout update_session_timeout;
630 * Function that will be called whenever the transport service wants to
631 * notify the plugin that the inbound quota changed and that the plugin
632 * should update it's delay for the next receive value
634 GNUNET_TRANSPORT_UpdateInboundDelay update_inbound_delay;
637 * Function that is used to query keepalive factor.
638 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
639 * calculate the interval between keepalive packets.
641 GNUNET_TRANSPORT_QueryKeepaliveFactorFunction query_keepalive_factor;
644 * Function to pretty-print addresses.
646 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
649 * Function that will be called to check if a binary address
650 * for this plugin is well-formed and corresponds to an
651 * address for THIS peer (as per our configuration). Naturally,
652 * if absolutely necessary, plugins can be a bit conservative in
653 * their answer, but in general plugins should make sure that the
654 * address does not redirect traffic to a 3rd party that might
655 * try to man-in-the-middle our traffic.
657 GNUNET_TRANSPORT_CheckAddress check_address;
660 * Function that will be called to convert a binary address
661 * to a string (numeric conversion only).
663 GNUNET_TRANSPORT_AddressToString address_to_string;
666 * Function that will be called to convert a string address
667 * to binary (numeric conversion only).
669 GNUNET_TRANSPORT_StringToAddress string_to_address;
672 * Function that will be called tell the plugin to create a session
675 GNUNET_TRANSPORT_CreateSession get_session;
678 * Function to obtain the network type for a session
680 GNUNET_TRANSPORT_GetNetworkType get_network;
683 * Function to monitor the sessions managed by the plugin.
685 GNUNET_TRANSPORT_SessionMonitorSetup setup_monitor;
689 /*#ifndef PLUGIN_TRANSPORT_H*/
691 /* end of gnunet_transport_plugin.h */