2 This file is part of GNUnet
3 (C) 2009 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.
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.
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 service_context value passed to the transport-service
62 * to identify the neighbour; will be NULL on the first
63 * call for a given peer
64 * @param latency estimated latency for communicating with the
65 * given peer; should be set to GNUNET_TIME_UNIT_FOREVER_REL
66 * until the transport has seen messages transmitted in
67 * BOTH directions (and hence been able to do an actual
68 * round-trip observation); a non-FOREVER latency is also used
69 * by the transport to know that communication in both directions
70 * using this one plugin actually works
71 * @param peer (claimed) identity of the other peer
72 * @param message the message, NULL if peer was disconnected
73 * @return the new service_context that the plugin should use
74 * for future receive calls for messages from this
77 typedef struct ReadyList *
78 (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
81 struct GNUNET_TIME_Relative
83 const struct GNUNET_PeerIdentity
85 const struct GNUNET_MessageHeader
90 * Function that will be called if we receive a validation
91 * of an address challenge that we transmitted to another
92 * peer. Note that the validation should only be considered
93 * acceptable if the challenge matches AND if the sender
94 * address is at least a plausible address for this peer
95 * (otherwise we may be seeing a MiM attack).
98 * @param name name of the transport that generated the address
99 * @param peer who responded to our challenge
100 * @param challenge the challenge number we presumably used
101 * @param sender_addr string describing our sender address (as observed
102 * by the other peer in human-readable format)
104 typedef void (*GNUNET_TRANSPORT_ValidationNotification) (void *cls,
106 const struct GNUNET_PeerIdentity *peer,
108 const char *sender_addr);
113 * Function that will be called for each address the transport
114 * is aware that it might be reachable under.
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 * @param expires when should this address automatically expire?
123 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
133 * Function that will be called for each address obtained from the HELLO.
136 * @param name name of the transport that generated the address
137 * @param addr one of the addresses of the host, NULL for the last address
138 * the specific address format depends on the transport
139 * @param addrlen length of the address
141 typedef void (*GNUNET_TRANSPORT_AddressCallback) (void *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 const struct GNUNET_CONFIGURATION_Handle *cfg;
162 struct GNUNET_SCHEDULER_Handle *sched;
167 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *my_public_key;
172 struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key;
175 * Identity of this peer.
177 const struct GNUNET_PeerIdentity *my_identity;
180 * Closure for the various callbacks.
185 * Function that should be called by the transport plugin
186 * whenever a message is received.
188 GNUNET_TRANSPORT_PluginReceiveCallback receive;
191 * Function that must be called by each plugin to notify the
192 * transport service about the addresses under which the transport
193 * provided by the plugin can be reached.
195 GNUNET_TRANSPORT_AddressNotification notify_address;
198 * Function that must be called by each plugin to notify the
199 * transport service about a successful validation of an
200 * address of another peer (or at least likely successful
203 GNUNET_TRANSPORT_ValidationNotification notify_validation;
206 * What is the default quota (in terms of incoming bytes per
207 * ms) for new connections?
209 uint32_t default_quota_in;
212 * What is the maximum number of connections that this transport
213 * should allow? Transports that do not have sessions (such as
214 * UDP) can ignore this value.
216 uint32_t max_connections;
222 * Function that can be used by the transport service to validate
223 * the address of another peer. Even if
224 * we already have a connection to this peer, this function is
225 * required to establish a new one.
228 * @param target who should receive this message
229 * @param challenge challenge code to use
230 * @param timeout how long should we try to transmit these?
231 * @param addrlen length of the address
232 * @param addr the address
233 * @return GNUNET_OK on success, GNUNET_SYSERR if the address
237 (*GNUNET_TRANSPORT_ValidationFunction) (void *cls,
239 GNUNET_PeerIdentity * target,
241 struct GNUNET_TIME_Relative
242 timeout, const void *addr,
246 * Function called by the GNUNET_TRANSPORT_TransmitFunction
250 * @param service_context value passed to the transport-service
251 * to identify the neighbour
252 * @param target who was the recipient of the message?
253 * @param result GNUNET_OK on success
254 * GNUNET_SYSERR if the target disconnected;
255 * disconnect will ALSO be signalled using
256 * the ReceiveCallback.
259 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
262 const struct GNUNET_PeerIdentity *
266 * Function that can be used by the transport service to transmit
267 * a message using the plugin. Note that in the case of a
268 * peer disconnecting, the continuation MUST be called
269 * prior to the disconnect notification itself. This function
270 * will be called with this peer's HELLO message to initiate
271 * a fresh connection to another peer.
274 * @param service_context value passed to the transport-service
275 * to identify the neighbour; NULL is used to indicate
276 * an urgent message. If the urgent message can not be
277 * scheduled for immediate transmission, the plugin is to
278 * call the continuation with failure immediately
279 * @param target who should receive this message
280 * @param priority how important is the message?
281 * @param msg the message to transmit
282 * @param timeout how long to wait at most for the transmission
283 * @param cont continuation to call once the message has
284 * been transmitted (or if the transport is ready
285 * for the next transmission call; or if the
286 * peer disconnected...); can be NULL
287 * @param cont_cls closure for cont
290 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
291 struct ReadyList * service_context,
292 const struct GNUNET_PeerIdentity *
294 unsigned int priority,
295 const struct GNUNET_MessageHeader *
297 struct GNUNET_TIME_Relative timeout,
298 GNUNET_TRANSPORT_TransmitContinuation
299 cont, void *cont_cls);
303 * Function that can be called to force a disconnect from the
304 * specified neighbour. This should also cancel all previously
305 * scheduled transmissions. Obviously the transmission may have been
306 * partially completed already, which is OK. The plugin is supposed
307 * to close the connection (if applicable) and no longer call the
308 * transmit continuation(s).
310 * Finally, plugin MUST NOT call the services's receive function to
311 * notify the service that the connection to the specified target was
312 * closed after a getting this call.
315 * @param service_context must correspond to the service context
316 * of the corresponding Transmit call; the plugin should
317 * not cancel a send call made with a different service
318 * context pointer! Never NULL.
319 * @param target peer for which the last transmission is
323 (*GNUNET_TRANSPORT_CancelFunction) (void *cls,
324 struct ReadyList * service_context,
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 * 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).
373 * @param peer the peer for whom the quota is given
374 * @param quota_in quota for receiving/sending data in bytes per ms
377 (*GNUNET_TRANSPORT_SetQuota) (void *cls,
378 const struct GNUNET_PeerIdentity * target,
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
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
394 (*GNUNET_TRANSPORT_SuggestAddress) (void *cls,
395 const void *addr, size_t addrlen);
398 * Each plugin is required to return a pointer to a struct of this
399 * type as the return value from its entry point.
401 struct GNUNET_TRANSPORT_PluginFunctions
405 * Closure for all of the callbacks.
410 * Function used to send a single message to a particular
411 * peer using the specified address. Used to validate
414 GNUNET_TRANSPORT_ValidationFunction validate;
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.
423 GNUNET_TRANSPORT_TransmitFunction send;
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).
430 GNUNET_TRANSPORT_CancelFunction cancel;
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 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.
445 GNUNET_TRANSPORT_SetQuota set_receive_quota;
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.
452 GNUNET_TRANSPORT_SuggestAddress address_suggested;
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:
461 * TCP < UDP < HTTP == HTTPS < SMTP
464 unsigned int cost_estimate;