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 include/gnunet_transport_plugin.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.
48 * Each 'struct Session' MUST start with the 'struct GNUNET_PeerIdentity'
49 * of the peer the session is for (which will be used for some error
50 * checking by the ATS code).
55 * Every 'struct Session' must begin with this header.
61 * Cached signature for PONG generation for the session. Do not use
64 struct GNUNET_CRYPTO_RsaSignature pong_signature;
67 * Expiration time for signature. Do not use in the plugin!
69 struct GNUNET_TIME_Absolute pong_sig_expires;
74 * Function that will be called whenever the plugin internally
75 * cleans up a session pointer and hence the service needs to
76 * discard all of those sessions as well. Plugins that do not
77 * use sessions can simply omit calling this function and always
78 * use NULL wherever a session pointer is needed. This function
79 * should be called BEFORE a potential "TransmitContinuation"
80 * from the "TransmitFunction".
83 * @param peer which peer was the session for
84 * @param session which session is being destoyed
86 typedef void (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
87 const struct GNUNET_PeerIdentity *
88 peer, struct Session * session);
92 * Function called by the transport for each received message.
93 * This function should also be called with "NULL" for the
94 * message to signal that the other peer disconnected.
97 * @param peer (claimed) identity of the other peer
98 * @param message the message, NULL if we only care about
99 * learning about the delay until we should receive again
100 * @param session identifier used for this session (NULL for plugins
101 * that do not offer bi-directional communication to the sender
102 * using the same "connection")
103 * @param sender_address binary address of the sender (if we established the
104 * connection or are otherwise sure of it; should be NULL
105 * for inbound TCP/UDP connections since it it not clear
106 * that we could establish ourselves a connection to that
107 * IP address and get the same system)
108 * @param sender_address_len number of bytes in sender_address
109 * @return how long the plugin should wait until receiving more data
110 * (plugins that do not support this, can ignore the return value)
113 GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
121 GNUNET_ATS_Information
135 * Function that will be called to figure if an address is an loopback,
136 * LAN, WAN etc. address
139 * @param addr binary address
140 * @param addrlen length of the address
141 * @return ATS Information containing the network type
143 typedef struct GNUNET_ATS_Information
144 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
145 const struct sockaddr *addr,
149 * Function that will be called for each address the transport
150 * is aware that it might be reachable under.
153 * @param add_remove should the address added (YES) or removed (NO) from the
154 * set of valid addresses?
155 * @param addr one of the addresses of the host
156 * the specific address format depends on the transport
157 * @param addrlen length of the address
158 * @param dest_plugin plugin to use this address with
160 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls, int add_remove,
163 const char *dest_plugin);
167 * Function that will be called whenever the plugin receives data over
168 * the network and wants to determine how long it should wait until
169 * the next time it reads from the given peer. Note that some plugins
170 * (such as UDP) may not be able to wait (for a particular peer), so
171 * the waiting part is optional. Plugins that can wait should call
172 * this function, sleep the given amount of time, and call it again
173 * (with zero bytes read) UNTIL it returns zero and only then read.
176 * @param peer which peer did we read data from
177 * @param amount_recved number of bytes read (can be zero)
178 * @return how long to wait until reading more from this peer
179 * (to enforce inbound quotas)
181 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void
192 * Function that returns a HELLO message.
194 typedef const struct GNUNET_MessageHeader *
195 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
199 * The transport service will pass a pointer to a struct
200 * of this type as the first and only argument to the
201 * entry point of each transport plugin.
203 struct GNUNET_TRANSPORT_PluginEnvironment
206 * Configuration to use.
208 const struct GNUNET_CONFIGURATION_Handle *cfg;
211 * Identity of this peer.
213 const struct GNUNET_PeerIdentity *my_identity;
216 * Closure for the various callbacks.
221 * Handle for reporting statistics.
223 struct GNUNET_STATISTICS_Handle *stats;
226 * Function that should be called by the transport plugin
227 * whenever a message is received. If this field is "NULL",
228 * the plugin should load in 'stub' mode and NOT fully
229 * initialize and instead only return an API with the
230 * 'address_pretty_printer', 'address_to_string' and
231 * 'string_to_address' functions.
233 GNUNET_TRANSPORT_PluginReceiveCallback receive;
237 * Function that returns our HELLO.
239 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
242 * Function that must be called by each plugin to notify the
243 * transport service about the addresses under which the transport
244 * provided by the plugin can be reached.
246 GNUNET_TRANSPORT_AddressNotification notify_address;
249 * Function that must be called by the plugin when a non-NULL
250 * session handle stops being valid (is destroyed).
252 GNUNET_TRANSPORT_SessionEnd session_end;
255 * Function that will be called to figure if an address is an loopback,
256 * LAN, WAN etc. address
258 GNUNET_TRANSPORT_AddressToType get_address_type;
262 * What is the maximum number of connections that this transport
263 * should allow? Transports that do not have sessions (such as
264 * UDP) can ignore this value.
266 uint32_t max_connections;
272 * Function called by the GNUNET_TRANSPORT_TransmitFunction
273 * upon "completion". In the case that a peer disconnects,
274 * this function must be called for each pending request
275 * (with a 'failure' indication) AFTER notifying the service
276 * about the disconnect event (so that the service won't try
277 * to transmit more messages, believing the connection still
281 * @param target who was the recipient of the message?
282 * @param result GNUNET_OK on success
283 * GNUNET_SYSERR if the target disconnected;
284 * disconnect will ALSO be signalled using
285 * the ReceiveCallback.
286 * @param size_payload bytes of payload from transport service in message
287 * @param size_on_wire bytes required on wire for transmission,
288 * 0 if result == GNUNET_SYSERR
290 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
292 GNUNET_PeerIdentity *
296 size_t size_on_wire);
299 * The new send function with just the session and no address
301 * Function that can be used by the transport service to transmit
302 * a message using the plugin. Note that in the case of a
303 * peer disconnecting, the continuation MUST be called
304 * prior to the disconnect notification itself. This function
305 * will be called with this peer's HELLO message to initiate
306 * a fresh connection to another peer.
309 * @param session which session must be used
310 * @param msgbuf the message to transmit
311 * @param msgbuf_size number of bytes in 'msgbuf'
312 * @param priority how important is the message (most plugins will
313 * ignore message priority and just FIFO)
314 * @param timeout how long to wait at most for the transmission (does not
315 * require plugins to discard the message after the timeout,
316 * just advisory for the desired delay; most plugins will ignore
318 * @param cont continuation to call once the message has
319 * been transmitted (or if the transport is ready
320 * for the next transmission call; or if the
321 * peer disconnected...); can be NULL
322 * @param cont_cls closure for cont
323 * @return number of bytes used (on the physical network, with overheads);
324 * -1 on hard errors (i.e. address invalid); 0 is a legal value
325 * and does NOT mean that the message was not transmitted (DV)
327 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
328 struct Session *session,
329 const char *msgbuf, size_t msgbuf_size,
330 unsigned int priority,
331 struct GNUNET_TIME_Relative to,
332 GNUNET_TRANSPORT_TransmitContinuation cont,
337 * Function that can be called to force a disconnect from the
338 * specified neighbour. This should also cancel all previously
339 * scheduled transmissions. Obviously the transmission may have been
340 * partially completed already, which is OK. The plugin is supposed
341 * to close the connection (if applicable) and no longer call the
342 * transmit continuation(s).
344 * Finally, plugin MUST NOT call the services's receive function to
345 * notify the service that the connection to the specified target was
346 * closed after a getting this call.
349 * @param target peer for which the last transmission is
352 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
354 GNUNET_PeerIdentity *
359 * Function called by the pretty printer for the resolved address for
360 * each human-readable address obtained.
363 * @param hostname one of the names for the host, NULL
364 * on the last call to the callback
366 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
367 const char *address);
371 * Convert the transports address to a nice, human-readable
375 * @param name name of the transport that generated the address
376 * @param addr one of the addresses of the host, NULL for the last address
377 * the specific address format depends on the transport
378 * @param addrlen length of the address
379 * @param numeric should (IP) addresses be displayed in numeric form?
380 * @param timeout after how long should we give up?
381 * @param asc function to call on each string
382 * @param asc_cls closure for asc
384 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
392 GNUNET_TRANSPORT_AddressStringCallback
397 * Another peer has suggested an address for this peer and transport
398 * plugin. Check that this could be a valid address. This function
399 * is not expected to 'validate' the address in the sense of trying to
400 * connect to it but simply to see if the binary format is technically
401 * legal for establishing a connection to this peer (and make sure that
402 * the address really corresponds to our network connection/settings
403 * and not some potential man-in-the-middle).
405 * @param addr pointer to the address
406 * @param addrlen length of addr
407 * @return GNUNET_OK if this is a plausible address for this peer
408 * and transport, GNUNET_SYSERR if not
410 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls, const void *addr,
414 * Create a new session to transmit data to the target
415 * This session will used to send data to this peer and the plugin will
416 * notify us by calling the env->session_end function
418 * @param cls the plugin
419 * @param target the neighbour id
420 * @param addr pointer to the address
421 * @param addrlen length of addr
422 * @return the session if the address is valid, NULL otherwise
424 typedef struct Session * (*GNUNET_TRANSPORT_CreateSession) (void *cls,
425 const struct GNUNET_HELLO_Address *address);
429 * Function called for a quick conversion of the binary address to
430 * a numeric address. Note that the caller must not free the
431 * address and that the next call to this function is allowed
432 * to override the address again.
435 * @param addr binary address
436 * @param addr_len length of the address
437 * @return string representing the same address
439 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
444 * Function called to convert a string address to
447 * @param cls closure ('struct Plugin*')
448 * @param addr string address
449 * @param addrlen length of the address including \0 termination
450 * @param buf location to store the buffer
451 * If the function returns GNUNET_SYSERR, its contents are undefined.
452 * @param added length of created address
453 * @return GNUNET_OK on success, GNUNET_SYSERR on failure
455 typedef int (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
463 * Each plugin is required to return a pointer to a struct of this
464 * type as the return value from its entry point.
466 struct GNUNET_TRANSPORT_PluginFunctions
470 * Closure for all of the callbacks.
475 * Function that the transport service will use to transmit data to
476 * another peer. May be NULL for plugins that only support
477 * receiving data. After this call, the plugin call the specified
478 * continuation with success or error before notifying us about the
479 * target having disconnected.
481 GNUNET_TRANSPORT_TransmitFunction send;
484 * Function that can be used to force the plugin to disconnect from
485 * the given peer and cancel all previous transmissions (and their
488 GNUNET_TRANSPORT_DisconnectFunction disconnect;
491 * Function to pretty-print addresses. NOTE: this function is not
492 * yet used by transport-service, but will be used in the future
493 * once the transport-API has been completed.
495 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
498 * Function that will be called to check if a binary address
499 * for this plugin is well-formed and corresponds to an
500 * address for THIS peer (as per our configuration). Naturally,
501 * if absolutely necessary, plugins can be a bit conservative in
502 * their answer, but in general plugins should make sure that the
503 * address does not redirect traffic to a 3rd party that might
504 * try to man-in-the-middle our traffic.
506 GNUNET_TRANSPORT_CheckAddress check_address;
509 * Function that will be called to convert a binary address
510 * to a string (numeric conversion only).
512 GNUNET_TRANSPORT_AddressToString address_to_string;
515 * Function that will be called to convert a string address
516 * to binary (numeric conversion only).
518 GNUNET_TRANSPORT_StringToAddress string_to_address;
521 * Function that will be called tell the plugin to create a session
524 GNUNET_TRANSPORT_CreateSession get_session;