2 This file is part of GNUnet
3 (C) 2009, 2010 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
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
8 option) any later version.
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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. If this field is "NULL",
222 * the plugin should load in 'stub' mode and NOT fully
223 * initialize and instead only return an API with the
224 * 'address_pretty_printer', 'address_to_string' and
225 * 'string_to_address' functions.
227 GNUNET_TRANSPORT_PluginReceiveCallback receive;
231 * Function that returns our HELLO.
233 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
236 * Function that must be called by each plugin to notify the
237 * transport service about the addresses under which the transport
238 * provided by the plugin can be reached.
240 GNUNET_TRANSPORT_AddressNotification notify_address;
243 * Function that must be called by the plugin when a non-NULL
244 * session handle stops being valid (is destroyed).
246 GNUNET_TRANSPORT_SessionEnd session_end;
249 * Function that will be called to figure if an address is an loopback,
250 * LAN, WAN etc. address
252 GNUNET_TRANSPORT_AddressToType get_address_type;
256 * What is the maximum number of connections that this transport
257 * should allow? Transports that do not have sessions (such as
258 * UDP) can ignore this value.
260 uint32_t max_connections;
266 * Function called by the GNUNET_TRANSPORT_TransmitFunction
267 * upon "completion". In the case that a peer disconnects,
268 * this function must be called for each pending request
269 * (with a 'failure' indication) AFTER notifying the service
270 * about the disconnect event (so that the service won't try
271 * to transmit more messages, believing the connection still
275 * @param target who was the recipient of the message?
276 * @param result GNUNET_OK on success
277 * GNUNET_SYSERR if the target disconnected;
278 * disconnect will ALSO be signalled using
279 * the ReceiveCallback.
281 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
283 GNUNET_PeerIdentity *
287 * The new send function with just the session and no address
289 * Function that can be used by the transport service to transmit
290 * a message using the plugin. Note that in the case of a
291 * peer disconnecting, the continuation MUST be called
292 * prior to the disconnect notification itself. This function
293 * will be called with this peer's HELLO message to initiate
294 * a fresh connection to another peer.
297 * @param session which session must be used
298 * @param msgbuf the message to transmit
299 * @param msgbuf_size number of bytes in 'msgbuf'
300 * @param priority how important is the message (most plugins will
301 * ignore message priority and just FIFO)
302 * @param timeout how long to wait at most for the transmission (does not
303 * require plugins to discard the message after the timeout,
304 * just advisory for the desired delay; most plugins will ignore
306 * @param cont continuation to call once the message has
307 * been transmitted (or if the transport is ready
308 * for the next transmission call; or if the
309 * peer disconnected...); can be NULL
310 * @param cont_cls closure for cont
311 * @return number of bytes used (on the physical network, with overheads);
312 * -1 on hard errors (i.e. address invalid); 0 is a legal value
313 * and does NOT mean that the message was not transmitted (DV)
315 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
316 struct Session *session,
317 const char *msgbuf, size_t msgbuf_size,
318 unsigned int priority,
319 struct GNUNET_TIME_Relative to,
320 GNUNET_TRANSPORT_TransmitContinuation cont, void *cont_cls);
324 * Function that can be called to force a disconnect from the
325 * specified neighbour. This should also cancel all previously
326 * scheduled transmissions. Obviously the transmission may have been
327 * partially completed already, which is OK. The plugin is supposed
328 * to close the connection (if applicable) and no longer call the
329 * transmit continuation(s).
331 * Finally, plugin MUST NOT call the services's receive function to
332 * notify the service that the connection to the specified target was
333 * closed after a getting this call.
336 * @param target peer for which the last transmission is
339 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
341 GNUNET_PeerIdentity *
346 * Function called by the pretty printer for the resolved address for
347 * each human-readable address obtained.
350 * @param hostname one of the names for the host, NULL
351 * on the last call to the callback
353 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
354 const char *address);
358 * Convert the transports address to a nice, human-readable
362 * @param name name of the transport that generated the address
363 * @param addr one of the addresses of the host, NULL for the last address
364 * the specific address format depends on the transport
365 * @param addrlen length of the address
366 * @param numeric should (IP) addresses be displayed in numeric form?
367 * @param timeout after how long should we give up?
368 * @param asc function to call on each string
369 * @param asc_cls closure for asc
371 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
379 GNUNET_TRANSPORT_AddressStringCallback
384 * Another peer has suggested an address for this peer and transport
385 * plugin. Check that this could be a valid address. This function
386 * is not expected to 'validate' the address in the sense of trying to
387 * connect to it but simply to see if the binary format is technically
388 * legal for establishing a connection to this peer (and make sure that
389 * the address really corresponds to our network connection/settings
390 * and not some potential man-in-the-middle).
392 * @param addr pointer to the address
393 * @param addrlen length of addr
394 * @return GNUNET_OK if this is a plausible address for this peer
395 * and transport, GNUNET_SYSERR if not
397 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls, const void *addr,
401 * Create a new session to transmit data to the target
402 * This session will used to send data to this peer and the plugin will
403 * notify us by calling the env->session_end function
405 * @param cls the plugin
406 * @param target the neighbour id
407 * @param addr pointer to the address
408 * @param addrlen length of addr
409 * @return the session if the address is valid, NULL otherwise
411 typedef struct Session * (*GNUNET_TRANSPORT_CreateSession) (void *cls,
412 const struct GNUNET_HELLO_Address *address);
416 * Function called for a quick conversion of the binary address to
417 * a numeric address. Note that the caller must not free the
418 * address and that the next call to this function is allowed
419 * to override the address again.
422 * @param addr binary address
423 * @param addr_len length of the address
424 * @return string representing the same address
426 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
431 * Function called to convert a string address to
434 * @param cls closure ('struct Plugin*')
435 * @param addr string address
436 * @param addrlen length of the address
437 * @param buf location to store the buffer
438 * If the function returns GNUNET_SYSERR, its contents are undefined.
439 * @param added length of created address
440 * @return GNUNET_OK on success, GNUNET_SYSERR on failure
442 typedef int (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
450 * Each plugin is required to return a pointer to a struct of this
451 * type as the return value from its entry point.
453 struct GNUNET_TRANSPORT_PluginFunctions
457 * Closure for all of the callbacks.
462 * Function that the transport service will use to transmit data to
463 * another peer. May be NULL for plugins that only support
464 * receiving data. After this call, the plugin call the specified
465 * continuation with success or error before notifying us about the
466 * target having disconnected.
468 GNUNET_TRANSPORT_TransmitFunction send;
471 * Function that can be used to force the plugin to disconnect from
472 * the given peer and cancel all previous transmissions (and their
475 GNUNET_TRANSPORT_DisconnectFunction disconnect;
478 * Function to pretty-print addresses. NOTE: this function is not
479 * yet used by transport-service, but will be used in the future
480 * once the transport-API has been completed.
482 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
485 * Function that will be called to check if a binary address
486 * for this plugin is well-formed and corresponds to an
487 * address for THIS peer (as per our configuration). Naturally,
488 * if absolutely necessary, plugins can be a bit conservative in
489 * their answer, but in general plugins should make sure that the
490 * address does not redirect traffic to a 3rd party that might
491 * try to man-in-the-middle our traffic.
493 GNUNET_TRANSPORT_CheckAddress check_address;
496 * Function that will be called to convert a binary address
497 * to a string (numeric conversion only).
499 GNUNET_TRANSPORT_AddressToString address_to_string;
502 * Function that will be called to convert a string address
503 * to binary (numeric conversion only).
505 GNUNET_TRANSPORT_StringToAddress string_to_address;
508 * Function that will be called tell the plugin to create a session
511 GNUNET_TRANSPORT_CreateSession get_session;