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.
10 GNUnet is distributed in the hope that it will be useful, but
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
16 along with GNUnet; see the file COPYING. If not, write to the
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 * ATS Handle to request address type.
208 struct GNUNET_ATS_SchedulingHandle *ats;
212 * Function that should be called by the transport plugin
213 * whenever a message is received.
215 GNUNET_TRANSPORT_PluginReceiveCallback receive;
219 * Function that returns our HELLO.
221 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
224 * Function that must be called by each plugin to notify the
225 * transport service about the addresses under which the transport
226 * provided by the plugin can be reached.
228 GNUNET_TRANSPORT_AddressNotification notify_address;
231 * Function that must be called by the plugin when a non-NULL
232 * session handle stops being valid (is destroyed).
234 GNUNET_TRANSPORT_SessionEnd session_end;
237 * What is the maximum number of connections that this transport
238 * should allow? Transports that do not have sessions (such as
239 * UDP) can ignore this value.
241 uint32_t max_connections;
247 * Function called by the GNUNET_TRANSPORT_TransmitFunction
248 * upon "completion". In the case that a peer disconnects,
249 * this function must be called for each pending request
250 * (with a 'failure' indication) AFTER notifying the service
251 * about the disconnect event (so that the service won't try
252 * to transmit more messages, believing the connection still
256 * @param target who was the recipient of the message?
257 * @param result GNUNET_OK on success
258 * GNUNET_SYSERR if the target disconnected;
259 * disconnect will ALSO be signalled using
260 * the ReceiveCallback.
262 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
264 GNUNET_PeerIdentity *
269 * Function that can be used by the transport service to transmit
270 * a message using the plugin. Note that in the case of a
271 * peer disconnecting, the continuation MUST be called
272 * prior to the disconnect notification itself. This function
273 * will be called with this peer's HELLO message to initiate
274 * a fresh connection to another peer.
277 * @param target who should receive this message
278 * @param msgbuf the message to transmit
279 * @param msgbuf_size number of bytes in 'msgbuf'
280 * @param priority how important is the message (most plugins will
281 * ignore message priority and just FIFO)
282 * @param timeout how long to wait at most for the transmission (does not
283 * require plugins to discard the message after the timeout,
284 * just advisory for the desired delay; most plugins will ignore
286 * @param session which session must be used (or NULL for "any")
287 * @param addr the address to use (can be NULL if the plugin
288 * is "on its own" (i.e. re-use existing TCP connection))
289 * @param addrlen length of the address in bytes
290 * @param force_address GNUNET_YES if the plugin MUST use the given address,
291 * GNUNET_NO means the plugin may use any other address and
292 * GNUNET_SYSERR means that only reliable existing
293 * bi-directional connections should be used (regardless
295 * @param cont continuation to call once the message has
296 * been transmitted (or if the transport is ready
297 * for the next transmission call; or if the
298 * peer disconnected...); can be NULL
299 * @param cont_cls closure for cont
300 * @return number of bytes used (on the physical network, with overheads);
301 * -1 on hard errors (i.e. address invalid); 0 is a legal value
302 * and does NOT mean that the message was not transmitted (DV)
304 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
306 GNUNET_PeerIdentity *
314 struct Session * session,
318 GNUNET_TRANSPORT_TransmitContinuation
319 cont, void *cont_cls);
323 * Function that can be called to force a disconnect from the
324 * specified neighbour. This should also cancel all previously
325 * scheduled transmissions. Obviously the transmission may have been
326 * partially completed already, which is OK. The plugin is supposed
327 * to close the connection (if applicable) and no longer call the
328 * transmit continuation(s).
330 * Finally, plugin MUST NOT call the services's receive function to
331 * notify the service that the connection to the specified target was
332 * closed after a getting this call.
335 * @param target peer for which the last transmission is
338 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
340 GNUNET_PeerIdentity *
345 * Function called by the pretty printer for the resolved address for
346 * each human-readable address obtained.
349 * @param hostname one of the names for the host, NULL
350 * on the last call to the callback
352 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
353 const char *address);
357 * Convert the transports address to a nice, human-readable
361 * @param name name of the transport that generated the address
362 * @param addr one of the addresses of the host, NULL for the last address
363 * the specific address format depends on the transport
364 * @param addrlen length of the address
365 * @param numeric should (IP) addresses be displayed in numeric form?
366 * @param timeout after how long should we give up?
367 * @param asc function to call on each string
368 * @param asc_cls closure for asc
370 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
378 GNUNET_TRANSPORT_AddressStringCallback
383 * Another peer has suggested an address for this peer and transport
384 * plugin. Check that this could be a valid address. This function
385 * is not expected to 'validate' the address in the sense of trying to
386 * connect to it but simply to see if the binary format is technically
387 * legal for establishing a connection to this peer (and make sure that
388 * the address really corresponds to our network connection/settings
389 * and not some potential man-in-the-middle).
391 * @param addr pointer to the address
392 * @param addrlen length of addr
393 * @return GNUNET_OK if this is a plausible address for this peer
394 * and transport, GNUNET_SYSERR if not
396 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls, const void *addr,
401 * Function called for a quick conversion of the binary address to
402 * a numeric address. Note that the caller must not free the
403 * address and that the next call to this function is allowed
404 * to override the address again.
407 * @param addr binary address
408 * @param addr_len length of the address
409 * @return string representing the same address
411 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
417 * Each plugin is required to return a pointer to a struct of this
418 * type as the return value from its entry point.
420 struct GNUNET_TRANSPORT_PluginFunctions
424 * Closure for all of the callbacks.
429 * Function that the transport service will use to transmit data to
430 * another peer. May be NULL for plugins that only support
431 * receiving data. After this call, the plugin call the specified
432 * continuation with success or error before notifying us about the
433 * target having disconnected.
435 GNUNET_TRANSPORT_TransmitFunction send;
438 * Function that can be used to force the plugin to disconnect from
439 * the given peer and cancel all previous transmissions (and their
442 GNUNET_TRANSPORT_DisconnectFunction disconnect;
445 * Function to pretty-print addresses. NOTE: this function is not
446 * yet used by transport-service, but will be used in the future
447 * once the transport-API has been completed.
449 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
452 * Function that will be called to check if a binary address
453 * for this plugin is well-formed and corresponds to an
454 * address for THIS peer (as per our configuration). Naturally,
455 * if absolutely necessary, plugins can be a bit conservative in
456 * their answer, but in general plugins should make sure that the
457 * address does not redirect traffic to a 3rd party that might
458 * try to man-in-the-middle our traffic.
460 GNUNET_TRANSPORT_CheckAddress check_address;
463 * Function that will be called to convert a binary address
464 * to a string (numeric conversion only).
466 GNUNET_TRANSPORT_AddressToString address_to_string;