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 const struct GNUNET_HELLO_Address *address,
89 struct Session *session,
90 const struct GNUNET_ATS_Information *ats,
95 * Function called by the transport for each received message.
96 * This function should also be called with "NULL" for the
97 * message to signal that the other peer disconnected.
100 * @param peer (claimed) identity of the other peer
101 * @param message the message, NULL if we only care about
102 * learning about the delay until we should receive again
103 * @param session identifier used for this session (NULL for plugins
104 * that do not offer bi-directional communication to the sender
105 * using the same "connection")
106 * @param sender_address binary address of the sender (if we established the
107 * connection or are otherwise sure of it; should be NULL
108 * for inbound TCP/UDP connections since it it not clear
109 * that we could establish ourselves a connection to that
110 * IP address and get the same system)
111 * @param sender_address_len number of bytes in @a sender_address
112 * @return how long the plugin should wait until receiving more data;
113 * returning #GNUNET_TIME_UNIT_FOREVER_REL means that the
114 * connection should be closed
116 typedef struct GNUNET_TIME_Relative
117 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
118 const struct GNUNET_HELLO_Address *address,
119 struct Session *session,
120 const struct GNUNET_MessageHeader *message);
124 * Function that can be called by plugins to figure if an address is
125 * an loopback, LAN or WAN address. Ultimately invokes
126 * #GNUNET_ATS_address_get_type().
129 * @param addr binary address
130 * @param addrlen length of the @a addr
131 * @return type of the network the address belongs to
133 typedef enum GNUNET_ATS_Network_Type
134 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
135 const struct sockaddr *addr,
140 * Function called when quality properties of an address change.
144 * @param address address
145 * @param address_len length of the @a address
146 * @param session session
147 * @param ats ATS information
148 * @param ats_count number entries in the @a ats array
151 (*GNUNET_TRANSPORT_UpdateAddressMetrics) (void *cls,
152 const struct GNUNET_HELLO_Address *address,
153 struct Session *session,
154 const struct GNUNET_ATS_Information *ats,
159 * Function that will be called for each address the transport
160 * is aware that it might be reachable under.
163 * @param add_remove should the address added (#GNUNET_YES) or removed (#GNUNET_NO) from the
164 * set of valid addresses?
165 * @param address the address to add or remove
168 (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
170 const struct GNUNET_HELLO_Address *address);
174 * Function that will be called whenever the plugin receives data over
175 * the network and wants to determine how long it should wait until
176 * the next time it reads from the given peer. Note that some plugins
177 * (such as UDP) may not be able to wait (for a particular peer), so
178 * the waiting part is optional. Plugins that can wait should call
179 * this function, sleep the given amount of time, and call it again
180 * (with zero bytes read) UNTIL it returns zero and only then read.
183 * @param peer which peer did we read data from
184 * @param amount_recved number of bytes read (can be zero)
185 * @return how long to wait until reading more from this peer
186 * (to enforce inbound quotas); returning #GNUNET_TIME_UNIT_FOREVER_REL
187 * means that the connection should be closed
189 typedef struct GNUNET_TIME_Relative
190 (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
191 const struct GNUNET_PeerIdentity *peer,
192 size_t amount_recved);
196 * Function that returns a HELLO message.
198 * @return HELLO message (FIXME with what?)
200 typedef const struct GNUNET_MessageHeader *
201 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
205 * The transport service will pass a pointer to a struct
206 * of this type as the first and only argument to the
207 * entry point of each transport plugin.
209 struct GNUNET_TRANSPORT_PluginEnvironment
212 * Configuration to use.
214 const struct GNUNET_CONFIGURATION_Handle *cfg;
217 * Identity of this peer.
219 const struct GNUNET_PeerIdentity *my_identity;
222 * Closure for the various callbacks.
227 * Handle for reporting statistics.
229 struct GNUNET_STATISTICS_Handle *stats;
232 * Function that should be called by the transport plugin
233 * whenever a message is received. If this field is "NULL",
234 * the plugin should load in 'stub' mode and NOT fully
235 * initialize and instead only return an API with the
236 * @e address_pretty_printer, @e address_to_string and
237 * @e string_to_address functions.
239 GNUNET_TRANSPORT_PluginReceiveCallback receive;
242 * Function that returns our HELLO.
244 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
247 * Function that must be called by each plugin to notify the
248 * transport service about the addresses under which the transport
249 * provided by the plugin can be reached.
251 GNUNET_TRANSPORT_AddressNotification notify_address;
254 * Function that must be called by the plugin when a non-NULL
255 * session handle stops being valid (is destroyed).
257 GNUNET_TRANSPORT_SessionEnd session_end;
260 * Function called by the plugin when a new (incoming) session was created
261 * not explicitly created using the the get_session function
263 GNUNET_TRANSPORT_SessionStart session_start;
266 * Function that will be called to figure if an address is an loopback,
267 * LAN, WAN etc. address
269 GNUNET_TRANSPORT_AddressToType get_address_type;
272 * Function that will be called to figure if an address is an loopback,
273 * LAN, WAN etc. address
275 GNUNET_TRANSPORT_UpdateAddressMetrics update_address_metrics;
278 * What is the maximum number of connections that this transport
279 * should allow? Transports that do not have sessions (such as
280 * UDP) can ignore this value.
282 uint32_t max_connections;
288 * Function called by the #GNUNET_TRANSPORT_TransmitFunction
289 * upon "completion". In the case that a peer disconnects,
290 * this function must be called for each pending request
291 * (with a 'failure' indication) AFTER notifying the service
292 * about the disconnect event (so that the service won't try
293 * to transmit more messages, believing the connection still
297 * @param target who was the recipient of the message?
298 * @param result #GNUNET_OK on success
299 * #GNUNET_SYSERR if the target disconnected;
300 * disconnect will ALSO be signalled using
301 * the ReceiveCallback.
302 * @param size_payload bytes of payload from transport service in message
303 * @param size_on_wire bytes required on wire for transmission,
304 * 0 if result == #GNUNET_SYSERR
307 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
308 const struct GNUNET_PeerIdentity *target,
311 size_t size_on_wire);
315 * The new send function with just the session and no address
317 * Function that can be used by the transport service to transmit
318 * a message using the plugin. Note that in the case of a
319 * peer disconnecting, the continuation MUST be called
320 * prior to the disconnect notification itself. This function
321 * will be called with this peer's HELLO message to initiate
322 * a fresh connection to another peer.
325 * @param session which session must be used
326 * @param msgbuf the message to transmit
327 * @param msgbuf_size number of bytes in @a msgbuf
328 * @param priority how important is the message (most plugins will
329 * ignore message priority and just FIFO)
330 * @param to how long to wait at most for the transmission (does not
331 * require plugins to discard the message after the timeout,
332 * just advisory for the desired delay; most plugins will ignore
334 * @param cont continuation to call once the message has
335 * been transmitted (or if the transport is ready
336 * for the next transmission call; or if the
337 * peer disconnected...); can be NULL
338 * @param cont_cls closure for @a cont
339 * @return number of bytes used (on the physical network, with overheads);
340 * -1 on hard errors (i.e. address invalid); 0 is a legal value
341 * and does NOT mean that the message was not transmitted (DV)
344 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
345 struct Session *session,
348 unsigned int priority,
349 struct GNUNET_TIME_Relative to,
350 GNUNET_TRANSPORT_TransmitContinuation cont,
355 * Function that can be called to force a disconnect from the
356 * specified neighbour for the given session only. . This should
357 * also cancel all previously scheduled transmissions for this
358 * session. Obviously the transmission may have been partially
359 * completed already, which is OK. The plugin is supposed to close
360 * the connection (if applicable).
362 * @param cls closure with the `struct Plugin`
363 * @param session session to destroy
364 * @return #GNUNET_OK on success
367 (*GNUNET_TRANSPORT_DisconnectSessionFunction) (void *cls,
368 struct Session *session);
372 * Function that is called to get the keepalive factor.
373 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
374 * calculate the interval between keepalive packets.
376 * @param cls closure with the `struct Plugin`
377 * @return keepalive factor
380 (*GNUNET_TRANSPORT_QueryKeepaliveFactorFunction) (void *cls);
384 * Function that can be called to force a disconnect from the
385 * specified neighbour. This should also cancel all previously
386 * scheduled transmissions. Obviously the transmission may have been
387 * partially completed already, which is OK. The plugin is supposed
388 * to close the connection (if applicable) and no longer call the
389 * transmit continuation(s).
392 * @param target peer for which the last transmission is
396 (*GNUNET_TRANSPORT_DisconnectPeerFunction) (void *cls,
397 const struct GNUNET_PeerIdentity *target);
401 * Function called by the pretty printer for the resolved address for
402 * each human-readable address obtained. The callback can be called
403 * several times. The last invocation must be with a @a address of
404 * NULL and a @a res of #GNUNET_OK. Thus, to indicate conversion
405 * errors, the callback might be called first with @a address NULL and
406 * @a res being #GNUNET_SYSERR. In that case, there must still be a
407 * subsequent call later with @a address NULL and @a res #GNUNET_OK.
410 * @param address one of the names for the host, NULL on last callback
411 * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on failure,
412 * #GNUNET_OK on last callback
415 (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
421 * Convert the transports address to a nice, human-readable
425 * @param type name of the transport that generated the address
426 * @param addr one of the addresses of the host, NULL for the last address
427 * the specific address format depends on the transport
428 * @param addrlen length of the @a addr
429 * @param numeric should (IP) addresses be displayed in numeric form?
430 * @param timeout after how long should we give up?
431 * @param asc function to call on each string
432 * @param asc_cls closure for @a asc
435 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
440 struct GNUNET_TIME_Relative timeout,
441 GNUNET_TRANSPORT_AddressStringCallback asc,
446 * Another peer has suggested an address for this peer and transport
447 * plugin. Check that this could be a valid address. This function
448 * is not expected to 'validate' the address in the sense of trying to
449 * connect to it but simply to see if the binary format is technically
450 * legal for establishing a connection to this peer (and make sure that
451 * the address really corresponds to our network connection/settings
452 * and not some potential man-in-the-middle).
454 * @param addr pointer to the address
455 * @param addrlen length of @a addr
456 * @return #GNUNET_OK if this is a plausible address for this peer
457 * and transport, #GNUNET_SYSERR if not
460 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
466 * Create a new session to transmit data to the target
467 * This session will used to send data to this peer and the plugin will
468 * notify us by calling the env->session_end function
470 * @param cls the plugin
471 * @param address the hello address
472 * @return the session if the address is valid, NULL otherwise
474 typedef struct Session *
475 (*GNUNET_TRANSPORT_CreateSession) (void *cls,
476 const struct GNUNET_HELLO_Address *address);
480 * Function that will be called whenever the transport service wants to
481 * notify the plugin that a session is still active and in use and
482 * therefore the session timeout for this session has to be updated
485 * @param peer which peer was the session for
486 * @param session which session is being updated
489 (*GNUNET_TRANSPORT_UpdateSessionTimeout) (void *cls,
490 const struct GNUNET_PeerIdentity *peer,
491 struct Session *session);
495 * Function that will be called whenever the transport service wants to
496 * notify the plugin that the inbound quota changed and that the plugin
497 * should update it's delay for the next receive value
500 * @param peer which peer was the session for
501 * @param session which session is being updated
502 * @param delay new delay to use for receiving
505 (*GNUNET_TRANSPORT_UpdateInboundDelay) (void *cls,
506 const struct GNUNET_PeerIdentity *peer,
507 struct Session *session,
508 struct GNUNET_TIME_Relative delay);
511 * Function called for a quick conversion of the binary address to
512 * a numeric address. Note that the caller must not free the
513 * address and that the next call to this function is allowed
514 * to override the address again.
517 * @param addr binary address
518 * @param addr_len length of the @a addr
519 * @return string representing the same address
522 (*GNUNET_TRANSPORT_AddressToString) (void *cls,
528 * Function called to convert a string address to
531 * @param cls closure (`struct Plugin*`)
532 * @param addr string address
533 * @param addrlen length of the @a addr including \0 termination
534 * @param buf location to store the buffer
535 * If the function returns #GNUNET_SYSERR, its contents are undefined.
536 * @param added length of created address
537 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
540 (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
548 * Function to obtain the network type for a session
550 * @param cls closure (`struct Plugin *`)
551 * @param session the session
552 * @return the network type
554 typedef enum GNUNET_ATS_Network_Type
555 (*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
556 struct Session *session);
560 * Function called by the plugin with information about the
561 * current sessions managed by the plugin (for monitoring).
564 * @param session session handle this information is about,
565 * NULL to indicate that we are "in sync" (initial
566 * iteration complete)
567 * @param info information about the state of the session,
568 * NULL if @a session is also NULL and we are
569 * merely signalling that the initial iteration is over
572 (*GNUNET_TRANSPORT_SessionInfoCallback) (void *cls,
573 struct Session *session,
574 const struct GNUNET_TRANSPORT_SessionInfo *info);
578 * Begin monitoring sessions of a plugin. There can only
579 * be one active monitor per plugin (i.e. if there are
580 * multiple monitors, the transport service needs to
581 * multiplex the generated events over all of them).
583 * @param cls closure of the plugin
584 * @param sic callback to invoke, NULL to disable monitor;
585 * plugin will being by iterating over all active
586 * sessions immediately and then enter monitor mode
587 * @param sic_cls closure for @a sic
590 (*GNUNET_TRANSPORT_SessionMonitorSetup) (void *cls,
591 GNUNET_TRANSPORT_SessionInfoCallback sic,
596 * Each plugin is required to return a pointer to a struct of this
597 * type as the return value from its entry point.
599 struct GNUNET_TRANSPORT_PluginFunctions
603 * Closure for all of the callbacks.
608 * Function that the transport service will use to transmit data to
609 * another peer. May be NULL for plugins that only support
610 * receiving data. After this call, the plugin call the specified
611 * continuation with success or error before notifying us about the
612 * target having disconnected.
614 GNUNET_TRANSPORT_TransmitFunction send;
617 * Function that can be used to force the plugin to disconnect from
618 * the given peer and cancel all previous transmissions (and their
621 GNUNET_TRANSPORT_DisconnectPeerFunction disconnect_peer;
624 * Function that can be used to force the plugin to disconnect from
625 * the given peer and cancel all previous transmissions (and their
628 GNUNET_TRANSPORT_DisconnectSessionFunction disconnect_session;
631 * Function that will be called whenever the transport service wants to
632 * notify the plugin that a session is still active and in use and
633 * therefore the session timeout for this session has to be updated
635 GNUNET_TRANSPORT_UpdateSessionTimeout update_session_timeout;
638 * Function that will be called whenever the transport service wants to
639 * notify the plugin that the inbound quota changed and that the plugin
640 * should update it's delay for the next receive value
642 GNUNET_TRANSPORT_UpdateInboundDelay update_inbound_delay;
645 * Function that is used to query keepalive factor.
646 * #GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT is divided by this number to
647 * calculate the interval between keepalive packets.
649 GNUNET_TRANSPORT_QueryKeepaliveFactorFunction query_keepalive_factor;
652 * Function to pretty-print addresses.
654 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
657 * Function that will be called to check if a binary address
658 * for this plugin is well-formed and corresponds to an
659 * address for THIS peer (as per our configuration). Naturally,
660 * if absolutely necessary, plugins can be a bit conservative in
661 * their answer, but in general plugins should make sure that the
662 * address does not redirect traffic to a 3rd party that might
663 * try to man-in-the-middle our traffic.
665 GNUNET_TRANSPORT_CheckAddress check_address;
668 * Function that will be called to convert a binary address
669 * to a string (numeric conversion only).
671 GNUNET_TRANSPORT_AddressToString address_to_string;
674 * Function that will be called to convert a string address
675 * to binary (numeric conversion only).
677 GNUNET_TRANSPORT_StringToAddress string_to_address;
680 * Function that will be called tell the plugin to create a session
683 GNUNET_TRANSPORT_CreateSession get_session;
686 * Function to obtain the network type for a session
688 GNUNET_TRANSPORT_GetNetworkType get_network;
691 * Function to monitor the sessions managed by the plugin.
693 GNUNET_TRANSPORT_SessionMonitorSetup setup_monitor;
697 /*#ifndef PLUGIN_TRANSPORT_H*/
699 /* end of gnunet_transport_plugin.h */