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 2, 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 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"
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.
52 * Function that will be called whenever the plugin internally
53 * cleans up a session pointer and hence the service needs to
54 * discard all of those sessions as well. Plugins that do not
55 * use sessions can simply omit calling this function and always
56 * use NULL wherever a session pointer is needed.
59 * @param peer which peer was the session for
60 * @param session which session is being destoyed
62 typedef void (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
63 const struct GNUNET_PeerIdentity *peer,
64 struct Session *session);
68 * Function called by the transport for each received message.
69 * This function should also be called with "NULL" for the
70 * message to signal that the other peer disconnected.
73 * @param peer (claimed) identity of the other peer
74 * @param message the message, NULL if we only care about
75 * learning about the delay until we should receive again -- FIXME!
76 * @param distance in overlay hops; use 1 unless DV (or 0 if message == NULL)
77 * @param session identifier used for this session (can be NULL)
78 * @param sender_address binary address of the sender (if observed)
79 * @param sender_address_len number of bytes in sender_address
80 * @return how long the plugin should wait until receiving more data
81 * (plugins that do not support this, can ignore the return value)
83 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
88 GNUNET_MessageHeader *
91 struct Session *session,
92 const char *sender_address,
93 size_t sender_address_len);
97 * Function that will be called for each address the transport
98 * is aware that it might be reachable under.
101 * @param name name of the transport that generated the address
102 * @param addr one of the addresses of the host, NULL for the last address
103 * the specific address format depends on the transport
104 * @param addrlen length of the address
105 * @param expires when should this address automatically expire?
107 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
117 * Function that will be called whenever the plugin receives data over
118 * the network and wants to determine how long it should wait until
119 * the next time it reads from the given peer. Note that some plugins
120 * (such as UDP) may not be able to wait (for a particular peer), so
121 * the waiting part is optional. Plugins that can wait should call
122 * this function, sleep the given amount of time, and call it again
123 * (with zero bytes read) UNTIL it returns zero and only then read.
126 * @param peer which peer did we read data from
127 * @param amount_recved number of bytes read (can be zero)
128 * @return how long to wait until reading more from this peer
129 * (to enforce inbound quotas)
131 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
133 GNUNET_PeerIdentity *peer,
134 size_t amount_recved);
138 * The transport service will pass a pointer to a struct
139 * of this type as the first and only argument to the
140 * entry point of each transport plugin.
142 struct GNUNET_TRANSPORT_PluginEnvironment
145 * Configuration to use.
147 const struct GNUNET_CONFIGURATION_Handle *cfg;
152 struct GNUNET_SCHEDULER_Handle *sched;
155 * Identity of this peer.
157 const struct GNUNET_PeerIdentity *my_identity;
160 * Closure for the various callbacks.
165 * Handle for reporting statistics.
167 struct GNUNET_STATISTICS_Handle *stats;
170 * Function that should be called by the transport plugin
171 * whenever a message is received.
173 GNUNET_TRANSPORT_PluginReceiveCallback receive;
176 * Function that must be called by each plugin to notify the
177 * transport service about the addresses under which the transport
178 * provided by the plugin can be reached.
180 GNUNET_TRANSPORT_AddressNotification notify_address;
183 * Inform service about traffic received, get information
184 * about when we might be willing to receive more.
186 GNUNET_TRANSPORT_TrafficReport traffic_report;
189 * Function that must be called by the plugin when a non-NULL
190 * session handle stops being valid (is destroyed).
192 GNUNET_TRANSPORT_SessionEnd session_end;
195 * What is the maximum number of connections that this transport
196 * should allow? Transports that do not have sessions (such as
197 * UDP) can ignore this value.
199 uint32_t max_connections;
205 * Function called by the GNUNET_TRANSPORT_TransmitFunction
209 * @param target who was the recipient of the message?
210 * @param result GNUNET_OK on success
211 * GNUNET_SYSERR if the target disconnected;
212 * disconnect will ALSO be signalled using
213 * the ReceiveCallback.
216 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
217 const struct GNUNET_PeerIdentity *
222 * Function that can be used by the transport service to transmit
223 * a message using the plugin. Note that in the case of a
224 * peer disconnecting, the continuation MUST be called
225 * prior to the disconnect notification itself. This function
226 * will be called with this peer's HELLO message to initiate
227 * a fresh connection to another peer.
230 * @param target who should receive this message
231 * @param msgbuf the message to transmit
232 * @param msgbuf_size number of bytes in 'msgbuf'
233 * @param priority how important is the message (most plugins will
234 * ignore message priority and just FIFO)
235 * @param timeout how long to wait at most for the transmission (does not
236 * require plugins to discard the message after the timeout,
237 * just advisory for the desired delay; most plugins will ignore
239 * @param session which session must be used (or NULL for "any")
240 * @param addr the address to use (can be NULL if the plugin
241 * is "on its own" (i.e. re-use existing TCP connection))
242 * @param addrlen length of the address in bytes
243 * @param force_address GNUNET_YES if the plugin MUST use the given address,
244 * GNUNET_NO means the plugin may use any other address and
245 * GNUNET_SYSERR means that only reliable existing
246 * bi-directional connections should be used (regardless
248 * @param cont continuation to call once the message has
249 * been transmitted (or if the transport is ready
250 * for the next transmission call; or if the
251 * peer disconnected...); can be NULL
252 * @param cont_cls closure for cont
253 * @return number of bytes used (on the physical network, with overheads);
254 * -1 on hard errors (i.e. address invalid); 0 is a legal value
255 * and does NOT mean that the message was not transmitted (DV)
258 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
259 const struct GNUNET_PeerIdentity *
264 struct GNUNET_TIME_Relative timeout,
265 struct Session *session,
269 GNUNET_TRANSPORT_TransmitContinuation
270 cont, void *cont_cls);
274 * Function that can be called to force a disconnect from the
275 * specified neighbour. This should also cancel all previously
276 * scheduled transmissions. Obviously the transmission may have been
277 * partially completed already, which is OK. The plugin is supposed
278 * to close the connection (if applicable) and no longer call the
279 * transmit continuation(s).
281 * Finally, plugin MUST NOT call the services's receive function to
282 * notify the service that the connection to the specified target was
283 * closed after a getting this call.
286 * @param target peer for which the last transmission is
290 (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
291 const struct GNUNET_PeerIdentity *
296 * Function called by the pretty printer for the resolved address for
297 * each human-readable address obtained.
300 * @param hostname one of the names for the host, NULL
301 * on the last call to the callback
303 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
304 const char *address);
308 * Convert the transports address to a nice, human-readable
312 * @param name name of the transport that generated the address
313 * @param addr one of the addresses of the host, NULL for the last address
314 * the specific address format depends on the transport
315 * @param addrlen length of the address
316 * @param numeric should (IP) addresses be displayed in numeric form?
317 * @param timeout after how long should we give up?
318 * @param asc function to call on each string
319 * @param asc_cls closure for asc
322 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
327 struct GNUNET_TIME_Relative
329 GNUNET_TRANSPORT_AddressStringCallback
334 * Another peer has suggested an address for this peer and transport
335 * plugin. Check that this could be a valid address. This function
336 * is not expected to 'validate' the address in the sense of trying to
337 * connect to it but simply to see if the binary format is technically
338 * legal for establishing a connection.
340 * @param addr pointer to the address, may be modified (slightly)
341 * @param addrlen length of addr
342 * @return GNUNET_OK if this is a plausible address for this peer
343 * and transport, GNUNET_SYSERR if not
346 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
347 void *addr, size_t addrlen);
351 * Function called for a quick conversion of the binary address to
352 * a numeric address. Note that the caller must not free the
353 * address and that the next call to this function is allowed
354 * to override the address again.
357 * @param addr binary address
358 * @param addr_len length of the address
359 * @return string representing the same address
361 typedef const char* (*GNUNET_TRANSPORT_AddressToString) (void *cls,
367 * Each plugin is required to return a pointer to a struct of this
368 * type as the return value from its entry point.
370 struct GNUNET_TRANSPORT_PluginFunctions
374 * Closure for all of the callbacks.
379 * Function that the transport service will use to transmit data to
380 * another peer. May be NULL for plugins that only support
381 * receiving data. After this call, the plugin call the specified
382 * continuation with success or error before notifying us about the
383 * target having disconnected.
385 GNUNET_TRANSPORT_TransmitFunction send;
388 * Function that can be used to force the plugin to disconnect from
389 * the given peer and cancel all previous transmissions (and their
390 * continuations). Note that if the transport does not have
391 * sessions / persistent connections (for example, UDP), this
392 * function may very well do nothing.
394 GNUNET_TRANSPORT_DisconnectFunction disconnect;
397 * Function to pretty-print addresses. NOTE: this function is not
398 * yet used by transport-service, but will be used in the future
399 * once the transport-API has been completed.
401 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
404 * Function that will be called to check if a binary address
405 * for this plugin is well-formed. If clearly needed, patch
406 * up information such as port numbers.
407 * FIXME: this API will likely change in the near future since
408 * it currently does not allow the size of the patched address
411 GNUNET_TRANSPORT_CheckAddress check_address;
415 * Function that will be called to convert a binary address
416 * to a string (numeric conversion only).
418 GNUNET_TRANSPORT_AddressToString address_to_string;