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 transport/plugin_transport.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 "transport_selection.h"
42 * Opaque pointer that plugins can use to distinguish specific
43 * connections to a given peer. Typically used by stateful plugins to
44 * allow the service to refer to specific streams instead of a more
45 * general notion of "some connection" to the given peer. This is
46 * useful since sometimes (i.e. for inbound TCP connections) a
47 * connection may not have an address that can be used for meaningful
48 * distinction between sessions to the same peer.
53 * Every 'struct Session' must begin with this header.
59 * Cached signature for PONG generation for the session. Do not use
62 struct GNUNET_CRYPTO_RsaSignature pong_signature;
65 * Expiration time for signature. Do not use in the plugin!
67 struct GNUNET_TIME_Absolute pong_sig_expires;
72 * Function that will be called whenever the plugin internally
73 * cleans up a session pointer and hence the service needs to
74 * discard all of those sessions as well. Plugins that do not
75 * use sessions can simply omit calling this function and always
76 * use NULL wherever a session pointer is needed.
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 *peer,
84 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 -- FIXME!
96 * @param distance in overlay hops; use 1 unless DV (or 0 if message == NULL)
97 * @param session identifier used for this session (NULL for plugins
98 * that do not offer bi-directional communication to the sender
99 * using the same "connection")
100 * @param sender_address binary address of the sender (if we established the
101 * connection or are otherwise sure of it; should be NULL
102 * for inbound TCP/UDP connections since it it not clear
103 * that we could establish ourselves a connection to that
104 * IP address and get the same system)
105 * @param sender_address_len number of bytes in sender_address
106 * @return how long the plugin should wait until receiving more data
107 * (plugins that do not support this, can ignore the return value)
109 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
111 GNUNET_PeerIdentity *
114 GNUNET_MessageHeader *
117 struct Session *session,
118 const char *sender_address,
119 uint16_t sender_address_len);
123 * Function that will be called for each address the transport
124 * is aware that it might be reachable under.
127 * @param name name of the transport that generated the address
128 * @param addr one of the addresses of the host, NULL for the last address
129 * the specific address format depends on the transport
130 * @param addrlen length of the address
131 * @param expires when should this address automatically expire?
133 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
142 * Function called whenever the plugin has to notify ATS about costs for using this transport
144 * The cost will be passed as struct GNUNET_ATS_Cost_Information[]
145 * This array is 0-terminated, so the last element will be a pair:
146 * ((cost->cost_type==GNUNET_ATS_ARRAY_TERMINATOR) && cost->cost_value==0))
150 * @param addr peer address
151 * @param addrlen address length
152 * @param cost pointer to the first element of struct GNUNET_ATS_Cost_Information[]
154 typedef void (*GNUNET_TRANSPORT_CostReport) (void *cls,
155 const struct GNUNET_PeerIdentity *peer,
158 struct GNUNET_ATS_Cost_Information * cost);
161 * The transport service will pass a pointer to a struct
162 * of this type as the first and only argument to the
163 * entry point of each transport plugin.
165 struct GNUNET_TRANSPORT_PluginEnvironment
168 * Configuration to use.
170 const struct GNUNET_CONFIGURATION_Handle *cfg;
175 struct GNUNET_SCHEDULER_Handle *sched;
178 * Identity of this peer.
180 const struct GNUNET_PeerIdentity *my_identity;
183 * Pointer (!) to our HELLO message. Note that the address
184 * referred to "*our_hello" might change over time.
186 struct GNUNET_HELLO_Message *const*our_hello;
189 * Closure for the various callbacks.
194 * Handle for reporting statistics.
196 struct GNUNET_STATISTICS_Handle *stats;
199 * Function that should be called by the transport plugin
200 * whenever a message is received.
202 GNUNET_TRANSPORT_PluginReceiveCallback receive;
205 * Function that must be called by each plugin to notify the
206 * transport service about the addresses under which the transport
207 * provided by the plugin can be reached.
209 GNUNET_TRANSPORT_AddressNotification notify_address;
212 * Inform service about traffic received, get information
213 * about when we might be willing to receive more.
215 GNUNET_TRANSPORT_TrafficReport traffic_report;
218 * Function that must be called by the plugin when a non-NULL
219 * session handle stops being valid (is destroyed).
221 GNUNET_TRANSPORT_SessionEnd session_end;
224 * Inform service about costs for using this transport plugin
226 GNUNET_TRANSPORT_CostReport cost_report;
229 * What is the maximum number of connections that this transport
230 * should allow? Transports that do not have sessions (such as
231 * UDP) can ignore this value.
233 uint32_t max_connections;
239 * Function called by the GNUNET_TRANSPORT_TransmitFunction
243 * @param target who was the recipient of the message?
244 * @param result GNUNET_OK on success
245 * GNUNET_SYSERR if the target disconnected;
246 * disconnect will ALSO be signalled using
247 * the ReceiveCallback.
250 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
251 const struct GNUNET_PeerIdentity *
256 * Function that can be used by the transport service to transmit
257 * a message using the plugin. Note that in the case of a
258 * peer disconnecting, the continuation MUST be called
259 * prior to the disconnect notification itself. This function
260 * will be called with this peer's HELLO message to initiate
261 * a fresh connection to another peer.
264 * @param target who should receive this message
265 * @param msgbuf the message to transmit
266 * @param msgbuf_size number of bytes in 'msgbuf'
267 * @param priority how important is the message (most plugins will
268 * ignore message priority and just FIFO)
269 * @param timeout how long to wait at most for the transmission (does not
270 * require plugins to discard the message after the timeout,
271 * just advisory for the desired delay; most plugins will ignore
273 * @param session which session must be used (or NULL for "any")
274 * @param addr the address to use (can be NULL if the plugin
275 * is "on its own" (i.e. re-use existing TCP connection))
276 * @param addrlen length of the address in bytes
277 * @param force_address GNUNET_YES if the plugin MUST use the given address,
278 * GNUNET_NO means the plugin may use any other address and
279 * GNUNET_SYSERR means that only reliable existing
280 * bi-directional connections should be used (regardless
282 * @param cont continuation to call once the message has
283 * been transmitted (or if the transport is ready
284 * for the next transmission call; or if the
285 * peer disconnected...); can be NULL
286 * @param cont_cls closure for cont
287 * @return number of bytes used (on the physical network, with overheads);
288 * -1 on hard errors (i.e. address invalid); 0 is a legal value
289 * and does NOT mean that the message was not transmitted (DV)
292 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
293 const struct GNUNET_PeerIdentity *
298 struct GNUNET_TIME_Relative timeout,
299 struct Session *session,
303 GNUNET_TRANSPORT_TransmitContinuation
304 cont, void *cont_cls);
308 * Function that can be called to force a disconnect from the
309 * specified neighbour. This should also cancel all previously
310 * scheduled transmissions. Obviously the transmission may have been
311 * partially completed already, which is OK. The plugin is supposed
312 * to close the connection (if applicable) and no longer call the
313 * transmit continuation(s).
315 * Finally, plugin MUST NOT call the services's receive function to
316 * notify the service that the connection to the specified target was
317 * closed after a getting this call.
320 * @param target peer for which the last transmission is
324 (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
325 const struct GNUNET_PeerIdentity *
330 * Function called by the pretty printer for the resolved address for
331 * each human-readable address obtained.
334 * @param hostname one of the names for the host, NULL
335 * on the last call to the callback
337 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
338 const char *address);
342 * Convert the transports address to a nice, human-readable
346 * @param name name of the transport that generated the address
347 * @param addr one of the addresses of the host, NULL for the last address
348 * the specific address format depends on the transport
349 * @param addrlen length of the address
350 * @param numeric should (IP) addresses be displayed in numeric form?
351 * @param timeout after how long should we give up?
352 * @param asc function to call on each string
353 * @param asc_cls closure for asc
356 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
361 struct GNUNET_TIME_Relative
363 GNUNET_TRANSPORT_AddressStringCallback
368 * Another peer has suggested an address for this peer and transport
369 * plugin. Check that this could be a valid address. This function
370 * is not expected to 'validate' the address in the sense of trying to
371 * connect to it but simply to see if the binary format is technically
372 * legal for establishing a connection to this peer (and make sure that
373 * the address really corresponds to our network connection/settings
374 * and not some potential man-in-the-middle).
376 * @param addr pointer to the address
377 * @param addrlen length of addr
378 * @return GNUNET_OK if this is a plausible address for this peer
379 * and transport, GNUNET_SYSERR if not
382 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
383 const void *addr, size_t addrlen);
387 * Function called for a quick conversion of the binary address to
388 * a numeric address. Note that the caller must not free the
389 * address and that the next call to this function is allowed
390 * to override the address again.
393 * @param addr binary address
394 * @param addr_len length of the address
395 * @return string representing the same address
397 typedef const char* (*GNUNET_TRANSPORT_AddressToString) (void *cls,
403 * Each plugin is required to return a pointer to a struct of this
404 * type as the return value from its entry point.
406 struct GNUNET_TRANSPORT_PluginFunctions
410 * Closure for all of the callbacks.
415 * Function that the transport service will use to transmit data to
416 * another peer. May be NULL for plugins that only support
417 * receiving data. After this call, the plugin call the specified
418 * continuation with success or error before notifying us about the
419 * target having disconnected.
421 GNUNET_TRANSPORT_TransmitFunction send;
424 * Function that can be used to force the plugin to disconnect from
425 * the given peer and cancel all previous transmissions (and their
426 * continuations). Note that if the transport does not have
427 * sessions / persistent connections (for example, UDP), this
428 * function may very well do nothing.
430 GNUNET_TRANSPORT_DisconnectFunction disconnect;
433 * Function to pretty-print addresses. NOTE: this function is not
434 * yet used by transport-service, but will be used in the future
435 * once the transport-API has been completed.
437 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
440 * Function that will be called to check if a binary address
441 * for this plugin is well-formed and corresponds to an
442 * address for THIS peer (as per our configuration). Naturally,
443 * if absolutely necessary, plugins can be a bit conservative in
444 * their answer, but in general plugins should make sure that the
445 * address does not redirect traffic to a 3rd party that might
446 * try to man-in-the-middle our traffic.
448 GNUNET_TRANSPORT_CheckAddress check_address;
451 * Function that will be called to convert a binary address
452 * to a string (numeric conversion only).
454 GNUNET_TRANSPORT_AddressToString address_to_string;