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.
15 You should have received a copy of the GNU General Public License
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
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 for each address the transport
132 * is aware that it might be reachable under.
135 * @param add_remove should the address added (YES) or removed (NO) from the
136 * set of valid addresses?
137 * @param addr one of the addresses of the host
138 * the specific address format depends on the transport
139 * @param addrlen length of the address
141 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls, int add_remove,
147 * Function that will be called whenever the plugin receives data over
148 * the network and wants to determine how long it should wait until
149 * the next time it reads from the given peer. Note that some plugins
150 * (such as UDP) may not be able to wait (for a particular peer), so
151 * the waiting part is optional. Plugins that can wait should call
152 * this function, sleep the given amount of time, and call it again
153 * (with zero bytes read) UNTIL it returns zero and only then read.
156 * @param peer which peer did we read data from
157 * @param amount_recved number of bytes read (can be zero)
158 * @return how long to wait until reading more from this peer
159 * (to enforce inbound quotas)
161 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void
172 * Function that returns a HELLO message.
174 typedef const struct GNUNET_MessageHeader
175 *(*GNUNET_TRANSPORT_GetHelloCallback) (void);
179 * The transport service will pass a pointer to a struct
180 * of this type as the first and only argument to the
181 * entry point of each transport plugin.
183 struct GNUNET_TRANSPORT_PluginEnvironment
186 * Configuration to use.
188 const struct GNUNET_CONFIGURATION_Handle *cfg;
191 * Identity of this peer.
193 const struct GNUNET_PeerIdentity *my_identity;
196 * Closure for the various callbacks.
201 * Handle for reporting statistics.
203 struct GNUNET_STATISTICS_Handle *stats;
206 * Function that should be called by the transport plugin
207 * whenever a message is received.
209 GNUNET_TRANSPORT_PluginReceiveCallback receive;
213 * Function that returns our HELLO.
215 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
218 * Function that must be called by each plugin to notify the
219 * transport service about the addresses under which the transport
220 * provided by the plugin can be reached.
222 GNUNET_TRANSPORT_AddressNotification notify_address;
225 * Function that must be called by the plugin when a non-NULL
226 * session handle stops being valid (is destroyed).
228 GNUNET_TRANSPORT_SessionEnd session_end;
231 * What is the maximum number of connections that this transport
232 * should allow? Transports that do not have sessions (such as
233 * UDP) can ignore this value.
235 uint32_t max_connections;
241 * Function called by the GNUNET_TRANSPORT_TransmitFunction
242 * upon "completion". In the case that a peer disconnects,
243 * this function must be called for each pending request
244 * (with a 'failure' indication) AFTER notifying the service
245 * about the disconnect event (so that the service won't try
246 * to transmit more messages, believing the connection still
250 * @param target who was the recipient of the message?
251 * @param result GNUNET_OK on success
252 * GNUNET_SYSERR if the target disconnected;
253 * disconnect will ALSO be signalled using
254 * the ReceiveCallback.
256 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
258 GNUNET_PeerIdentity *
263 * Function that can be used by the transport service to transmit
264 * a message using the plugin. Note that in the case of a
265 * peer disconnecting, the continuation MUST be called
266 * prior to the disconnect notification itself. This function
267 * will be called with this peer's HELLO message to initiate
268 * a fresh connection to another peer.
271 * @param target who should receive this message
272 * @param msgbuf the message to transmit
273 * @param msgbuf_size number of bytes in 'msgbuf'
274 * @param priority how important is the message (most plugins will
275 * ignore message priority and just FIFO)
276 * @param timeout how long to wait at most for the transmission (does not
277 * require plugins to discard the message after the timeout,
278 * just advisory for the desired delay; most plugins will ignore
280 * @param session which session must be used (or NULL for "any")
281 * @param addr the address to use (can be NULL if the plugin
282 * is "on its own" (i.e. re-use existing TCP connection))
283 * @param addrlen length of the address in bytes
284 * @param force_address GNUNET_YES if the plugin MUST use the given address,
285 * GNUNET_NO means the plugin may use any other address and
286 * GNUNET_SYSERR means that only reliable existing
287 * bi-directional connections should be used (regardless
289 * @param cont continuation to call once the message has
290 * been transmitted (or if the transport is ready
291 * for the next transmission call; or if the
292 * peer disconnected...); can be NULL
293 * @param cont_cls closure for cont
294 * @return number of bytes used (on the physical network, with overheads);
295 * -1 on hard errors (i.e. address invalid); 0 is a legal value
296 * and does NOT mean that the message was not transmitted (DV)
298 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
300 GNUNET_PeerIdentity *
308 struct Session * session,
312 GNUNET_TRANSPORT_TransmitContinuation
313 cont, void *cont_cls);
317 * Function that can be called to force a disconnect from the
318 * specified neighbour. This should also cancel all previously
319 * scheduled transmissions. Obviously the transmission may have been
320 * partially completed already, which is OK. The plugin is supposed
321 * to close the connection (if applicable) and no longer call the
322 * transmit continuation(s).
324 * Finally, plugin MUST NOT call the services's receive function to
325 * notify the service that the connection to the specified target was
326 * closed after a getting this call.
329 * @param target peer for which the last transmission is
332 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
334 GNUNET_PeerIdentity *
339 * Function called by the pretty printer for the resolved address for
340 * each human-readable address obtained.
343 * @param hostname one of the names for the host, NULL
344 * on the last call to the callback
346 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
347 const char *address);
351 * Convert the transports address to a nice, human-readable
355 * @param name name of the transport that generated the address
356 * @param addr one of the addresses of the host, NULL for the last address
357 * the specific address format depends on the transport
358 * @param addrlen length of the address
359 * @param numeric should (IP) addresses be displayed in numeric form?
360 * @param timeout after how long should we give up?
361 * @param asc function to call on each string
362 * @param asc_cls closure for asc
364 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
372 GNUNET_TRANSPORT_AddressStringCallback
377 * Another peer has suggested an address for this peer and transport
378 * plugin. Check that this could be a valid address. This function
379 * is not expected to 'validate' the address in the sense of trying to
380 * connect to it but simply to see if the binary format is technically
381 * legal for establishing a connection to this peer (and make sure that
382 * the address really corresponds to our network connection/settings
383 * and not some potential man-in-the-middle).
385 * @param addr pointer to the address
386 * @param addrlen length of addr
387 * @return GNUNET_OK if this is a plausible address for this peer
388 * and transport, GNUNET_SYSERR if not
390 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls, const void *addr,
395 * Function called for a quick conversion of the binary address to
396 * a numeric address. Note that the caller must not free the
397 * address and that the next call to this function is allowed
398 * to override the address again.
401 * @param addr binary address
402 * @param addr_len length of the address
403 * @return string representing the same address
405 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
411 * Each plugin is required to return a pointer to a struct of this
412 * type as the return value from its entry point.
414 struct GNUNET_TRANSPORT_PluginFunctions
418 * Closure for all of the callbacks.
423 * Function that the transport service will use to transmit data to
424 * another peer. May be NULL for plugins that only support
425 * receiving data. After this call, the plugin call the specified
426 * continuation with success or error before notifying us about the
427 * target having disconnected.
429 GNUNET_TRANSPORT_TransmitFunction send;
432 * Function that can be used to force the plugin to disconnect from
433 * the given peer and cancel all previous transmissions (and their
436 GNUNET_TRANSPORT_DisconnectFunction disconnect;
439 * Function to pretty-print addresses. NOTE: this function is not
440 * yet used by transport-service, but will be used in the future
441 * once the transport-API has been completed.
443 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
446 * Function that will be called to check if a binary address
447 * for this plugin is well-formed and corresponds to an
448 * address for THIS peer (as per our configuration). Naturally,
449 * if absolutely necessary, plugins can be a bit conservative in
450 * their answer, but in general plugins should make sure that the
451 * address does not redirect traffic to a 3rd party that might
452 * try to man-in-the-middle our traffic.
454 GNUNET_TRANSPORT_CheckAddress check_address;
457 * Function that will be called to convert a binary address
458 * to a string (numeric conversion only).
460 GNUNET_TRANSPORT_AddressToString address_to_string;