2 This file is part of GNUnet
3 (C) 2009 Christian Grothoff (and other contributing authors)
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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
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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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.
31 * - consider moving DATA message (latency measurement)
32 * to service; avoids encapsulation overheads and
33 * would enable latency measurements for non-bidi
37 * @author Christian Grothoff
39 #ifndef PLUGIN_TRANSPORT_H
40 #define PLUGIN_TRANSPORT_H
42 #include "gnunet_configuration_lib.h"
43 #include "gnunet_scheduler_lib.h"
44 #include "gnunet_transport_service.h"
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
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.
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
80 typedef struct ReadyList *
81 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
85 struct GNUNET_TIME_Relative
87 const struct GNUNET_PeerIdentity
89 const struct GNUNET_MessageHeader
94 * Function that will be called for each address the transport
95 * is aware that it might be reachable under.
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?
104 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
114 * Function that will be called for each address obtained from the HELLO.
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
122 typedef void (*GNUNET_TRANSPORT_AddressCallback) (void *cls,
129 * Function that allows a transport to query the known
130 * network addresses for a given peer.
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
138 typedef void (*GNUNET_TRANSPORT_LookupAddress) (void *cls,
139 struct GNUNET_TIME_Relative
142 GNUNET_PeerIdentity * target,
143 GNUNET_TRANSPORT_AddressCallback
144 iter, void *iter_cls);
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.
152 struct GNUNET_TRANSPORT_PluginEnvironment
155 * Configuration to use.
157 struct GNUNET_CONFIGURATION_Handle *cfg;
162 struct GNUNET_SCHEDULER_Handle *sched;
167 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *my_public_key;
170 * Closure for the various callbacks.
175 * Function that should be called by the transport plugin
176 * whenever a message is received.
178 GNUNET_TRANSPORT_PluginReceiveCallback receive;
181 * Address lookup function.
183 GNUNET_TRANSPORT_LookupAddress lookup;
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.
190 GNUNET_TRANSPORT_AddressNotification notify_address;
193 * What is the default quota (in terms of incoming bytes per
194 * ms) for new connections?
196 uint32_t default_quota_in;
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.
203 uint32_t max_connections;
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).
215 * @param target who should receive this message
216 * @param priority how important is the message
217 * @param msg1 first message to transmit
218 * @param msg2 second message to transmit (can be NULL)
219 * @param timeout how long should we try to transmit these?
220 * @param addrlen length of the address
221 * @param addr the address
222 * @return session instance if the transmission has been scheduled
223 * NULL if the address format is invalid
226 (*GNUNET_TRANSPORT_TransmitToAddressFunction) (void *cls,
228 GNUNET_PeerIdentity * target,
229 unsigned int priority,
231 GNUNET_MessageHeader * msg1,
233 GNUNET_MessageHeader * msg2,
234 struct GNUNET_TIME_Relative
235 timeout, const void *addr,
239 * Function called by the GNUNET_TRANSPORT_TransmitFunction
243 * @param service_context value passed to the transport-service
244 * to identify the neighbour
245 * @param target who was the recipient of the message?
246 * @param result GNUNET_OK on success
247 * GNUNET_SYSERR if the target disconnected;
248 * disconnect will ALSO be signalled using
249 * the ReceiveCallback.
252 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
255 const struct GNUNET_PeerIdentity *
259 * Function that can be used by the transport service to transmit
260 * a message using the plugin. Note that in the case of a
261 * peer disconnecting, the continuation MUST be called
262 * prior to the disconnect notification itself. This function
263 * will be called with this peer's HELLO message to initiate
264 * a fresh connection to another peer.
267 * @param plugin_context value we were asked to pass to this plugin
268 * to respond to the given peer (use is optional,
269 * but may speed up processing), can be NULL
270 * @param service_context value passed to the transport-service
271 * to identify the neighbour; NULL is used to indicate
272 * an urgent message. If the urgent message can not be
273 * scheduled for immediate transmission, the plugin is to
274 * call the continuation with failure immediately
275 * @param target who should receive this message
276 * @param priority how important is the message?
277 * @param msg the message to transmit
278 * @param timeout how long to wait at most for the transmission
279 * @param cont continuation to call once the message has
280 * been transmitted (or if the transport is ready
281 * for the next transmission call; or if the
282 * peer disconnected...); can be NULL
283 * @param cont_cls closure for cont
284 * @return plugin_context that should be used next time for
285 * sending messages to the specified peer
288 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
289 void *plugin_context,
290 struct ReadyList * service_context,
291 const struct GNUNET_PeerIdentity *
293 unsigned int priority,
294 const struct GNUNET_MessageHeader *
296 struct GNUNET_TIME_Relative timeout,
297 GNUNET_TRANSPORT_TransmitContinuation
298 cont, void *cont_cls);
302 * Function that can be called to force a disconnect from the
303 * specified neighbour. This should also cancel all previously
304 * scheduled transmissions. Obviously the transmission may have been
305 * partially completed already, which is OK. The plugin is supposed
306 * to close the connection (if applicable) and no longer call the
307 * transmit continuation(s).
309 * Finally, plugin MUST NOT call the services's receive function to
310 * notify the service that the connection to the specified target was
311 * closed after a getting this call.
314 * @param plugin_context value we were asked to pass to this plugin
315 * to respond to the given peer (use is optional,
316 * but may speed up processing), can be NULL (if
317 * NULL was returned from the transmit function)
318 * @param service_context must correspond to the service context
319 * of the corresponding Transmit call; the plugin should
320 * not cancel a send call made with a different service
321 * context pointer! Never NULL.
322 * @param target peer for which the last transmission is
326 (*GNUNET_TRANSPORT_CancelFunction) (void *cls,
327 void *plugin_context,
328 struct ReadyList * service_context,
329 const struct GNUNET_PeerIdentity *
334 * Function called by the pretty printer for the resolved address for
335 * each human-readable address obtained.
338 * @param hostname one of the names for the host, NULL
339 * on the last call to the callback
341 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
342 const char *address);
346 * Convert the transports address to a nice, human-readable
350 * @param name name of the transport that generated the address
351 * @param addr one of the addresses of the host, NULL for the last address
352 * the specific address format depends on the transport
353 * @param addrlen length of the address
354 * @param numeric should (IP) addresses be displayed in numeric form?
355 * @param timeout after how long should we give up?
356 * @param asc function to call on each string
357 * @param asc_cls closure for asc
360 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
365 struct GNUNET_TIME_Relative
367 GNUNET_TRANSPORT_AddressStringCallback
372 * Set a quota for receiving data from the given peer; this is a
373 * per-transport limit. The transport should limit its read/select
374 * calls to stay below the quota (in terms of incoming data).
377 * @param peer the peer for whom the quota is given
378 * @param quota_in quota for receiving/sending data in bytes per ms
381 (*GNUNET_TRANSPORT_SetQuota) (void *cls,
382 const struct GNUNET_PeerIdentity * target,
387 * Another peer has suggested an address for this
388 * peer and transport plugin. Check that this could be a valid
389 * address. If so, consider adding it to the list
392 * @param addr pointer to the address
393 * @param addrlen length of addr
394 * @return GNUNET_OK if this is a plausible address for this peer
398 (*GNUNET_TRANSPORT_SuggestAddress) (void *cls,
399 const void *addr, size_t addrlen);
402 * Each plugin is required to return a pointer to a struct of this
403 * type as the return value from its entry point.
405 struct GNUNET_TRANSPORT_PluginFunctions
409 * Closure for all of the callbacks.
414 * Function used to send a single message to a particular
415 * peer using the specified address. Used to validate
418 GNUNET_TRANSPORT_TransmitToAddressFunction send_to;
421 * Function that the transport service will use to transmit data to
422 * another peer. May be null for plugins that only support
423 * receiving data. After this call, the plugin call the specified
424 * continuation with success or error before notifying us about the
425 * target having disconnected.
427 GNUNET_TRANSPORT_TransmitFunction send;
430 * Function that can be used to force the plugin to disconnect
431 * from the given peer and cancel all previous transmissions
432 * (and their continuationc).
434 GNUNET_TRANSPORT_CancelFunction cancel;
437 * Function to pretty-print addresses. NOTE: this function is not
438 * yet used by transport-service, but will be used in the future
439 * once the transport-API has been completed.
441 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
444 * Function that the transport service can use to try to enforce a
445 * quota for the number of bytes received via this transport.
446 * Transports that can not refuse incoming data (such as UDP)
447 * are free to ignore these calls.
449 GNUNET_TRANSPORT_SetQuota set_receive_quota;
452 * Function that will be called if another peer suggested that
453 * we should use a particular address (since he is reaching
454 * us at that address) for this transport.
456 GNUNET_TRANSPORT_SuggestAddress address_suggested;
459 * Relative cost of this transport compared to others. This
460 * is supposed to be a static cost estimate which determines
461 * which plugins should not even be attempted if other,
462 * cheaper transports are already working. The idea is that
463 * the costs have roughly this relationship:
465 * TCP < UDP < HTTP == HTTPS < SMTP
468 unsigned int cost_estimate;