2 This file is part of GNUnet
3 (C) 2009, 2010 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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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"
40 * Opaque pointer that plugins can use to distinguish specific
41 * connections to a given peer. Typically used by stateful plugins to
42 * allow the service to refer to specific streams instead of a more
43 * general notion of "some connection" to the given peer. This is
44 * useful since sometimes (i.e. for inbound TCP connections) a
45 * connection may not have an address that can be used for meaningful
46 * distinction between sessions to the same peer.
51 * Every 'struct Session' must begin with this header.
57 * Cached signature for PONG generation for the session. Do not use
60 struct GNUNET_CRYPTO_RsaSignature pong_signature;
63 * Expiration time for signature. Do not use in the plugin!
65 struct GNUNET_TIME_Absolute pong_sig_expires;
70 * Function that will be called whenever the plugin internally
71 * cleans up a session pointer and hence the service needs to
72 * discard all of those sessions as well. Plugins that do not
73 * use sessions can simply omit calling this function and always
74 * use NULL wherever a session pointer is needed. This function
75 * should be called BEFORE a potential "TransmitContinuation"
76 * from the "TransmitFunction".
79 * @param peer which peer was the session for
80 * @param session which session is being destoyed
82 typedef void (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
83 const struct GNUNET_PeerIdentity *
84 peer, struct Session * session);
88 * Function called by the transport for each received message.
89 * This function should also be called with "NULL" for the
90 * message to signal that the other peer disconnected.
93 * @param peer (claimed) identity of the other peer
94 * @param message the message, NULL if we only care about
95 * learning about the delay until we should receive again
96 * @param session identifier used for this session (NULL for plugins
97 * that do not offer bi-directional communication to the sender
98 * using the same "connection")
99 * @param sender_address binary address of the sender (if we established the
100 * connection or are otherwise sure of it; should be NULL
101 * for inbound TCP/UDP connections since it it not clear
102 * that we could establish ourselves a connection to that
103 * IP address and get the same system)
104 * @param sender_address_len number of bytes in sender_address
105 * @return how long the plugin should wait until receiving more data
106 * (plugins that do not support this, can ignore the return value)
109 GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
117 GNUNET_ATS_Information
131 * Function that will be called to figure if an address is an loopback,
132 * LAN, WAN etc. address
135 * @param addr binary address
136 * @param addrlen length of the address
137 * @return ATS Information containing the network type
139 typedef const struct GNUNET_ATS_Information
140 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
141 const struct sockaddr *addr,
145 * Function that will be called for each address the transport
146 * is aware that it might be reachable under.
149 * @param add_remove should the address added (YES) or removed (NO) from the
150 * set of valid addresses?
151 * @param addr one of the addresses of the host
152 * the specific address format depends on the transport
153 * @param addrlen length of the address
155 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls, int add_remove,
161 * Function that will be called whenever the plugin receives data over
162 * the network and wants to determine how long it should wait until
163 * the next time it reads from the given peer. Note that some plugins
164 * (such as UDP) may not be able to wait (for a particular peer), so
165 * the waiting part is optional. Plugins that can wait should call
166 * this function, sleep the given amount of time, and call it again
167 * (with zero bytes read) UNTIL it returns zero and only then read.
170 * @param peer which peer did we read data from
171 * @param amount_recved number of bytes read (can be zero)
172 * @return how long to wait until reading more from this peer
173 * (to enforce inbound quotas)
175 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void
186 * Function that returns a HELLO message.
188 typedef const struct GNUNET_MessageHeader
189 *(*GNUNET_TRANSPORT_GetHelloCallback) (void);
193 * The transport service will pass a pointer to a struct
194 * of this type as the first and only argument to the
195 * entry point of each transport plugin.
197 struct GNUNET_TRANSPORT_PluginEnvironment
200 * Configuration to use.
202 const struct GNUNET_CONFIGURATION_Handle *cfg;
205 * Identity of this peer.
207 const struct GNUNET_PeerIdentity *my_identity;
210 * Closure for the various callbacks.
215 * Handle for reporting statistics.
217 struct GNUNET_STATISTICS_Handle *stats;
220 * Function that should be called by the transport plugin
221 * whenever a message is received.
223 GNUNET_TRANSPORT_PluginReceiveCallback receive;
227 * Function that returns our HELLO.
229 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
232 * Function that must be called by each plugin to notify the
233 * transport service about the addresses under which the transport
234 * provided by the plugin can be reached.
236 GNUNET_TRANSPORT_AddressNotification notify_address;
239 * Function that must be called by the plugin when a non-NULL
240 * session handle stops being valid (is destroyed).
242 GNUNET_TRANSPORT_SessionEnd session_end;
245 * Function that will be called to figure if an address is an loopback,
246 * LAN, WAN etc. address
248 GNUNET_TRANSPORT_AddressToType get_address_type;
252 * What is the maximum number of connections that this transport
253 * should allow? Transports that do not have sessions (such as
254 * UDP) can ignore this value.
256 uint32_t max_connections;
262 * Function called by the GNUNET_TRANSPORT_TransmitFunction
263 * upon "completion". In the case that a peer disconnects,
264 * this function must be called for each pending request
265 * (with a 'failure' indication) AFTER notifying the service
266 * about the disconnect event (so that the service won't try
267 * to transmit more messages, believing the connection still
271 * @param target who was the recipient of the message?
272 * @param result GNUNET_OK on success
273 * GNUNET_SYSERR if the target disconnected;
274 * disconnect will ALSO be signalled using
275 * the ReceiveCallback.
277 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
279 GNUNET_PeerIdentity *
284 * Function that can be used by the transport service to transmit
285 * a message using the plugin. Note that in the case of a
286 * peer disconnecting, the continuation MUST be called
287 * prior to the disconnect notification itself. This function
288 * will be called with this peer's HELLO message to initiate
289 * a fresh connection to another peer.
292 * @param target who should receive this message
293 * @param msgbuf the message to transmit
294 * @param msgbuf_size number of bytes in 'msgbuf'
295 * @param priority how important is the message (most plugins will
296 * ignore message priority and just FIFO)
297 * @param timeout how long to wait at most for the transmission (does not
298 * require plugins to discard the message after the timeout,
299 * just advisory for the desired delay; most plugins will ignore
301 * @param session which session must be used (or NULL for "any")
302 * @param addr the address to use (can be NULL if the plugin
303 * is "on its own" (i.e. re-use existing TCP connection))
304 * @param addrlen length of the address in bytes
305 * @param force_address GNUNET_YES if the plugin MUST use the given address,
306 * GNUNET_NO means the plugin may use any other address and
307 * GNUNET_SYSERR means that only reliable existing
308 * bi-directional connections should be used (regardless
310 * @param cont continuation to call once the message has
311 * been transmitted (or if the transport is ready
312 * for the next transmission call; or if the
313 * peer disconnected...); can be NULL
314 * @param cont_cls closure for cont
315 * @return number of bytes used (on the physical network, with overheads);
316 * -1 on hard errors (i.e. address invalid); 0 is a legal value
317 * and does NOT mean that the message was not transmitted (DV)
319 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
321 GNUNET_PeerIdentity *
329 struct Session * session,
333 GNUNET_TRANSPORT_TransmitContinuation
334 cont, void *cont_cls);
338 * The new send function with just the session and no address
340 * Function that can be used by the transport service to transmit
341 * a message using the plugin. Note that in the case of a
342 * peer disconnecting, the continuation MUST be called
343 * prior to the disconnect notification itself. This function
344 * will be called with this peer's HELLO message to initiate
345 * a fresh connection to another peer.
348 * @param target who should receive this message
349 * @param msgbuf the message to transmit
350 * @param msgbuf_size number of bytes in 'msgbuf'
351 * @param priority how important is the message (most plugins will
352 * ignore message priority and just FIFO)
353 * @param timeout how long to wait at most for the transmission (does not
354 * require plugins to discard the message after the timeout,
355 * just advisory for the desired delay; most plugins will ignore
357 * @param session which session must be used (or NULL for "any")
358 * @param addr the address to use (can be NULL if the plugin
359 * is "on its own" (i.e. re-use existing TCP connection))
360 * @param addrlen length of the address in bytes
361 * @param force_address GNUNET_YES if the plugin MUST use the given address,
362 * GNUNET_NO means the plugin may use any other address and
363 * GNUNET_SYSERR means that only reliable existing
364 * bi-directional connections should be used (regardless
366 * @param cont continuation to call once the message has
367 * been transmitted (or if the transport is ready
368 * for the next transmission call; or if the
369 * peer disconnected...); can be NULL
370 * @param cont_cls closure for cont
371 * @return number of bytes used (on the physical network, with overheads);
372 * -1 on hard errors (i.e. address invalid); 0 is a legal value
373 * and does NOT mean that the message was not transmitted (DV)
375 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunctionWithSession) (void *cls,
376 struct Session *session,
377 const char *msgbuf, size_t msgbuf_size,
378 unsigned int priority,
379 struct GNUNET_TIME_Relative to,
380 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_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).
391 * Finally, plugin MUST NOT call the services's receive function to
392 * notify the service that the connection to the specified target was
393 * closed after a getting this call.
396 * @param target peer for which the last transmission is
399 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
401 GNUNET_PeerIdentity *
406 * Function called by the pretty printer for the resolved address for
407 * each human-readable address obtained.
410 * @param hostname one of the names for the host, NULL
411 * on the last call to the callback
413 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
414 const char *address);
418 * Convert the transports address to a nice, human-readable
422 * @param name name of the transport that generated the address
423 * @param addr one of the addresses of the host, NULL for the last address
424 * the specific address format depends on the transport
425 * @param addrlen length of the address
426 * @param numeric should (IP) addresses be displayed in numeric form?
427 * @param timeout after how long should we give up?
428 * @param asc function to call on each string
429 * @param asc_cls closure for asc
431 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
439 GNUNET_TRANSPORT_AddressStringCallback
444 * Another peer has suggested an address for this peer and transport
445 * plugin. Check that this could be a valid address. This function
446 * is not expected to 'validate' the address in the sense of trying to
447 * connect to it but simply to see if the binary format is technically
448 * legal for establishing a connection to this peer (and make sure that
449 * the address really corresponds to our network connection/settings
450 * and not some potential man-in-the-middle).
452 * @param addr pointer to the address
453 * @param addrlen length of addr
454 * @return GNUNET_OK if this is a plausible address for this peer
455 * and transport, GNUNET_SYSERR if not
457 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls, const void *addr,
461 * Create a new session to transmit data to the target
462 * This session will used to send data to this peer and the plugin will
463 * notify us by calling the env->session_end function
465 * @param cls the plugin
466 * @param target the neighbour id
467 * @param addr pointer to the address
468 * @param addrlen length of addr
469 * @return the session if the address is valid, NULL otherwise
471 typedef struct Session * (*GNUNET_TRANSPORT_CreateSession) (void *cls,
472 const struct GNUNET_HELLO_Address *address);
476 * Function called for a quick conversion of the binary address to
477 * a numeric address. Note that the caller must not free the
478 * address and that the next call to this function is allowed
479 * to override the address again.
482 * @param addr binary address
483 * @param addr_len length of the address
484 * @return string representing the same address
486 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
492 * Each plugin is required to return a pointer to a struct of this
493 * type as the return value from its entry point.
495 struct GNUNET_TRANSPORT_PluginFunctions
499 * Closure for all of the callbacks.
504 * Function that the transport service will use to transmit data to
505 * another peer. May be NULL for plugins that only support
506 * receiving data. After this call, the plugin call the specified
507 * continuation with success or error before notifying us about the
508 * target having disconnected.
510 GNUNET_TRANSPORT_TransmitFunction send;
514 * Will be renamed to "send" when implementation is done
517 GNUNET_TRANSPORT_TransmitFunctionWithSession send_with_session;
520 * Function that can be used to force the plugin to disconnect from
521 * the given peer and cancel all previous transmissions (and their
524 GNUNET_TRANSPORT_DisconnectFunction disconnect;
527 * Function to pretty-print addresses. NOTE: this function is not
528 * yet used by transport-service, but will be used in the future
529 * once the transport-API has been completed.
531 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
534 * Function that will be called to check if a binary address
535 * for this plugin is well-formed and corresponds to an
536 * address for THIS peer (as per our configuration). Naturally,
537 * if absolutely necessary, plugins can be a bit conservative in
538 * their answer, but in general plugins should make sure that the
539 * address does not redirect traffic to a 3rd party that might
540 * try to man-in-the-middle our traffic.
542 GNUNET_TRANSPORT_CheckAddress check_address;
545 * Function that will be called to convert a binary address
546 * to a string (numeric conversion only).
548 GNUNET_TRANSPORT_AddressToString address_to_string;
551 * Function that will be called tell the plugin to create a session
554 GNUNET_TRANSPORT_CreateSession get_session;