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1/*
2 This file is part of GNUnet
3 (C) 2009 Christian Grothoff (and other contributing authors)
4
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.
9
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.
14
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.
19*/
20
21/**
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 *
30 * TODO:
31 * - consider moving DATA message (latency measurement)
32 * to service; avoids encapsulation overheads and
33 * would enable latency measurements for non-bidi
34 * transports.
35 * -
36 *
37 * @author Christian Grothoff
38 */
39#ifndef PLUGIN_TRANSPORT_H
40#define PLUGIN_TRANSPORT_H
41
42#include "gnunet_configuration_lib.h"
43#include "gnunet_scheduler_lib.h"
44#include "gnunet_transport_service.h"
45
46/**
47 * Opaque internal context for a particular peer of the transport
48 * service. Plugins will be given a pointer to this type and, if
49 * cheaply possible, should pass this pointer back to the transport
50 * service whenever additional messages from the same peer are
51 * received.
52 */
53struct ReadyList;
54
55/**
56 * Function called by the transport for each received message.
57 * This function should also be called with "NULL" for the
58 * message to signal that the other peer disconnected.
59 *
60 * @param cls closure
61 * @param plugin_context value to pass to this plugin
62 * to respond to the given peer (use is optional,
63 * but may speed up processing)
64 * @param service_context value passed to the transport-service
65 * to identify the neighbour; will be NULL on the first
66 * call for a given peer
67 * @param latency estimated latency for communicating with the
68 * given peer; should be set to GNUNET_TIME_UNIT_FOREVER_REL
69 * until the transport has seen messages transmitted in
70 * BOTH directions (and hence been able to do an actual
71 * round-trip observation); a non-FOREVER latency is also used
72 * by the transport to know that communication in both directions
73 * using this one plugin actually works
74 * @param peer (claimed) identity of the other peer
75 * @param message the message, NULL if peer was disconnected
76 * @return the new service_context that the plugin should use
77 * for future receive calls for messages from this
78 * particular peer
79 */
80typedef struct ReadyList *
81 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
82 void *plugin_context,
83 struct ReadyList *
84 service_context,
85 struct GNUNET_TIME_Relative
86 latency,
87 const struct GNUNET_PeerIdentity
88 * peer,
89 const struct GNUNET_MessageHeader
90 * message);
91
92
93/**
94 * Function that will be called for each address the transport
95 * is aware that it might be reachable under.
96 *
97 * @param cls closure
98 * @param name name of the transport that generated the address
99 * @param addr one of the addresses of the host, NULL for the last address
100 * the specific address format depends on the transport
101 * @param addrlen length of the address
102 * @param expires when should this address automatically expire?
103 */
104typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
105 const char *name,
106 const void *addr,
107 size_t addrlen,
108 struct
109 GNUNET_TIME_Relative
110 expires);
111
112
113/**
114 * Function that will be called for each address obtained from the HELLO.
115 *
116 * @param cls closure
117 * @param name name of the transport that generated the address
118 * @param addr one of the addresses of the host, NULL for the last address
119 * the specific address format depends on the transport
120 * @param addrlen length of the address
121 */
122typedef void (*GNUNET_TRANSPORT_AddressCallback) (void *cls,
123 const char *name,
124 const void *addr,
125 size_t addrlen);
126
127
128/**
129 * Function that allows a transport to query the known
130 * network addresses for a given peer.
131 *
132 * @param cls closure
133 * @param timeout after how long should we time out?
134 * @param target which peer are we looking for?
135 * @param iter function to call for each known address
136 * @param iter_cls closure for iter
137 */
138typedef void (*GNUNET_TRANSPORT_LookupAddress) (void *cls,
139 struct GNUNET_TIME_Relative
140 timeout,
141 const struct
142 GNUNET_PeerIdentity * target,
143 GNUNET_TRANSPORT_AddressCallback
144 iter, void *iter_cls);
145
146
147/**
148 * The transport service will pass a pointer to a struct
149 * of this type as the first and only argument to the
150 * entry point of each transport plugin.
151 */
152struct GNUNET_TRANSPORT_PluginEnvironment
153{
154 /**
155 * Configuration to use.
156 */
157 struct GNUNET_CONFIGURATION_Handle *cfg;
158
159 /**
160 * Scheduler to use.
161 */
162 struct GNUNET_SCHEDULER_Handle *sched;
163
164 /**
165 * Our public key.
166 */
167 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *my_public_key;
168
169 /**
170 * Closure for the various callbacks.
171 */
172 void *cls;
173
174 /**
175 * Function that should be called by the transport plugin
176 * whenever a message is received.
177 */
178 GNUNET_TRANSPORT_PluginReceiveCallback receive;
179
180 /**
181 * Address lookup function.
182 */
183 GNUNET_TRANSPORT_LookupAddress lookup;
184
185 /**
186 * Function that must be called by each plugin to notify the
187 * transport service about the addresses under which the transport
188 * provided by the plugin can be reached.
189 */
190 GNUNET_TRANSPORT_AddressNotification notify_address;
191
192 /**
193 * What is the default quota (in terms of incoming bytes per
194 * ms) for new connections?
195 */
196 uint32_t default_quota_in;
197
198 /**
199 * What is the maximum number of connections that this transport
200 * should allow? Transports that do not have sessions (such as
201 * UDP) can ignore this value.
202 */
203 uint32_t max_connections;
204
205};
206
207
208/**
209 * Function that can be used by the transport service to transmit
210 * a message using the plugin using a fresh connection (even if
211 * we already have a connection to this peer, this function is
212 * required to establish a new one).
213 *
214 * @param cls closure
215 * @param target who should receive this message
216 * @param msg1 first message to transmit
217 * @param msg2 second message to transmit (can be NULL)
218 * @param timeout how long should we try to transmit these?
219 * @param addrlen length of the address
220 * @param addr the address
221 * @return session instance if the transmission has been scheduled
222 * NULL if the address format is invalid
223 */
224typedef void *
225 (*GNUNET_TRANSPORT_TransmitToAddressFunction) (void *cls,
226 const struct
227 GNUNET_PeerIdentity * target,
228 const struct
229 GNUNET_MessageHeader * msg1,
230 const struct
231 GNUNET_MessageHeader * msg2,
232 struct GNUNET_TIME_Relative
233 timeout, const void *addr,
234 size_t addrlen);
235
236/**
237 * Function called by the GNUNET_TRANSPORT_TransmitFunction
238 * upon "completion".
239 *
240 * @param cls closure
241 * @param service_context value passed to the transport-service
242 * to identify the neighbour
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.
248 */
249typedef void
250 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
251 struct ReadyList *
252 service_context,
253 const struct GNUNET_PeerIdentity *
254 target, int result);
255
256/**
257 * Function that can be used by the transport service to transmit
258 * a message using the plugin. Note that in the case of a
259 * peer disconnecting, the continuation MUST be called
260 * prior to the disconnect notification itself. This function
261 * will be called with this peer's HELLO message to initiate
262 * a fresh connection to another peer.
263 *
264 * @param cls closure
265 * @param plugin_context value we were asked to pass to this plugin
266 * to respond to the given peer (use is optional,
267 * but may speed up processing), can be NULL
268 * @param service_context value passed to the transport-service
269 * to identify the neighbour; NULL is used to indicate
270 * an urgent message. If the urgent message can not be
271 * scheduled for immediate transmission, the plugin is to
272 * call the continuation with failure immediately
273 * @param target who should receive this message
274 * @param msg the message to transmit
275 * @param timeout how long to wait at most for the transmission
276 * @param cont continuation to call once the message has
277 * been transmitted (or if the transport is ready
278 * for the next transmission call; or if the
279 * peer disconnected...); can be NULL
280 * @param cont_cls closure for cont
281 * @return plugin_context that should be used next time for
282 * sending messages to the specified peer
283 */
284typedef void *
285 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
286 void *plugin_context,
287 struct ReadyList * service_context,
288 const struct GNUNET_PeerIdentity *
289 target,
290 const struct GNUNET_MessageHeader *
291 msg,
292 struct GNUNET_TIME_Relative timeout,
293 GNUNET_TRANSPORT_TransmitContinuation
294 cont, void *cont_cls);
295
296
297/**
298 * Function that can be called to force a disconnect from the
299 * specified neighbour. This should also cancel all previously
300 * scheduled transmissions. Obviously the transmission may have been
301 * partially completed already, which is OK. The plugin is supposed
302 * to close the connection (if applicable) and no longer call the
303 * transmit continuation(s).
304 *
305 * Finally, plugin MUST NOT call the services's receive function to
306 * notify the service that the connection to the specified target was
307 * closed after a getting this call.
308 *
309 * @param cls closure
310 * @param plugin_context value we were asked to pass to this plugin
311 * to respond to the given peer (use is optional,
312 * but may speed up processing), can be NULL (if
313 * NULL was returned from the transmit function)
314 * @param service_context must correspond to the service context
315 * of the corresponding Transmit call; the plugin should
316 * not cancel a send call made with a different service
317 * context pointer! Never NULL.
318 * @param target peer for which the last transmission is
319 * to be cancelled
320 */
321typedef void
322 (*GNUNET_TRANSPORT_CancelFunction) (void *cls,
323 void *plugin_context,
324 struct ReadyList * service_context,
325 const struct GNUNET_PeerIdentity *
326 target);
327
328
329/**
330 * Function called by the pretty printer for the resolved address for
331 * each human-readable address obtained.
332 *
333 * @param cls closure
334 * @param hostname one of the names for the host, NULL
335 * on the last call to the callback
336 */
337typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
338 const char *address);
339
340
341/**
342 * Convert the transports address to a nice, human-readable
343 * format.
344 *
345 * @param cls closure
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
354 */
355typedef void
356 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
357 const char *type,
358 const void *addr,
359 size_t addrlen,
360 int numeric,
361 struct GNUNET_TIME_Relative
362 timeout,
363 GNUNET_TRANSPORT_AddressStringCallback
364 asc, void *asc_cls);
365
366
367/**
368 * Set a quota for receiving data from the given peer; this is a
369 * per-transport limit. The transport should limit its read/select
370 * calls to stay below the quota (in terms of incoming data).
371 *
372 * @param cls closure
373 * @param peer the peer for whom the quota is given
374 * @param quota_in quota for receiving/sending data in bytes per ms
375 */
376typedef void
377 (*GNUNET_TRANSPORT_SetQuota) (void *cls,
378 const struct GNUNET_PeerIdentity * target,
379 uint32_t quota_in);
380
381
382/**
383 * Another peer has suggested an address for this
384 * peer and transport plugin. Check that this could be a valid
385 * address. If so, consider adding it to the list
386 * of addresses.
387 *
388 * @param addr pointer to the address
389 * @param addrlen length of addr
390 * @return GNUNET_OK if this is a plausible address for this peer
391 * and transport
392 */
393typedef int
394 (*GNUNET_TRANSPORT_SuggestAddress) (void *cls,
395 const void *addr, size_t addrlen);
396
397/**
398 * Each plugin is required to return a pointer to a struct of this
399 * type as the return value from its entry point.
400 */
401struct GNUNET_TRANSPORT_PluginFunctions
402{
403
404 /**
405 * Closure for all of the callbacks.
406 */
407 void *cls;
408
409 /**
410 * Function used to send a single message to a particular
411 * peer using the specified address. Used to validate
412 * HELLOs.
413 */
414 GNUNET_TRANSPORT_TransmitToAddressFunction send_to;
415
416 /**
417 * Function that the transport service will use to transmit data to
418 * another peer. May be null for plugins that only support
419 * receiving data. After this call, the plugin call the specified
420 * continuation with success or error before notifying us about the
421 * target having disconnected.
422 */
423 GNUNET_TRANSPORT_TransmitFunction send;
424
425 /**
426 * Function that can be used to force the plugin to disconnect
427 * from the given peer and cancel all previous transmissions
428 * (and their continuationc).
429 */
430 GNUNET_TRANSPORT_CancelFunction cancel;
431
432 /**
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.
436 */
437 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
438
439 /**
440 * Function that the transport service can use to try to enforce a
441 * quota for the number of bytes received via this transport.
442 * Transports that can not refuse incoming data (such as UDP)
443 * are free to ignore these calls.
444 */
445 GNUNET_TRANSPORT_SetQuota set_receive_quota;
446
447 /**
448 * Function that will be called if another peer suggested that
449 * we should use a particular address (since he is reaching
450 * us at that address) for this transport.
451 */
452 GNUNET_TRANSPORT_SuggestAddress address_suggested;
453
454 /**
455 * Relative cost of this transport compared to others. This
456 * is supposed to be a static cost estimate which determines
457 * which plugins should not even be attempted if other,
458 * cheaper transports are already working. The idea is that
459 * the costs have roughly this relationship:
460 * <pre>
461 * TCP < UDP < HTTP == HTTPS < SMTP
462 * </pre>
463 */
464 unsigned int cost_estimate;
465};
466
467
468#endif