2 This file is part of GNUnet
3 (C) 2009, 2010 Christian Grothoff (and other contributing authors)
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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"
38 #include "gnunet_ats_service.h"
40 #define TRANSPORT_SESSION_INBOUND_STRING "<inbound>"
43 * Opaque pointer that plugins can use to distinguish specific
44 * connections to a given peer. Typically used by stateful plugins to
45 * allow the service to refer to specific streams instead of a more
46 * general notion of "some connection" to the given peer. This is
47 * useful since sometimes (i.e. for inbound TCP connections) a
48 * connection may not have an address that can be used for meaningful
49 * distinction between sessions to the same peer.
51 * Each 'struct Session' MUST start with the 'struct GNUNET_PeerIdentity'
52 * of the peer the session is for (which will be used for some error
53 * checking by the ATS code).
58 * Every 'struct Session' must begin with this header.
66 * Function that will be called whenever the plugin internally
67 * cleans up a session pointer and hence the service needs to
68 * discard all of those sessions as well. Plugins that do not
69 * use sessions can simply omit calling this function and always
70 * use NULL wherever a session pointer is needed. This function
71 * should be called BEFORE a potential "TransmitContinuation"
72 * from the "TransmitFunction".
75 * @param peer which peer was the session for
76 * @param session which session is being destoyed
78 typedef void (*GNUNET_TRANSPORT_SessionEnd) (void *cls,
79 const struct GNUNET_PeerIdentity *peer,
80 struct Session * session);
84 * Function that will be called whenever the plugin internally
85 * creates a new session and hence transport need to tell ATS.
86 * This happens when we have a inbound connection we did not
91 * @param plugin plugin
92 * @param address address
93 * @param address_len length of the address
94 * @param session session
95 * @param ats ATS information
96 * @param ats_count number of ATS information contained
99 (*GNUNET_TRANSPORT_SessionStart) (void *cls,
100 const struct GNUNET_PeerIdentity *peer,
103 uint16_t address_len,
104 struct Session *session,
105 const struct GNUNET_ATS_Information *ats,
109 * Function called by the transport for each received message.
110 * This function should also be called with "NULL" for the
111 * message to signal that the other peer disconnected.
114 * @param peer (claimed) identity of the other peer
115 * @param message the message, NULL if we only care about
116 * learning about the delay until we should receive again
117 * @param session identifier used for this session (NULL for plugins
118 * that do not offer bi-directional communication to the sender
119 * using the same "connection")
120 * @param sender_address binary address of the sender (if we established the
121 * connection or are otherwise sure of it; should be NULL
122 * for inbound TCP/UDP connections since it it not clear
123 * that we could establish ourselves a connection to that
124 * IP address and get the same system)
125 * @param sender_address_len number of bytes in sender_address
126 * @return how long the plugin should wait until receiving more data
127 * (plugins that do not support this, can ignore the return value)
130 GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
131 const struct GNUNET_PeerIdentity *peer,
132 const struct GNUNET_MessageHeader *message,
133 struct Session *session,
134 const char *sender_address,
135 uint16_t sender_address_len);
139 * Function that will be called to figure if an address is an loopback,
140 * LAN, WAN etc. address
143 * @param addr binary address
144 * @param addrlen length of the address
145 * @return ATS Information containing the network type
147 typedef struct GNUNET_ATS_Information
148 (*GNUNET_TRANSPORT_AddressToType) (void *cls,
149 const struct sockaddr *addr,
154 * Function called when quality properties of an address change.
158 * @param address address
159 * @param address_len length of the address
160 * @param session session
161 * @param ats ATS information
162 * @param ats_count number of ATS information contained
165 (*GNUNET_TRANSPORT_UpdateAddressMetrics) (void *cls,
166 const struct GNUNET_PeerIdentity *peer,
168 uint16_t address_len,
169 struct Session *session,
170 const struct GNUNET_ATS_Information *ats,
174 * Function that will be called for each address the transport
175 * is aware that it might be reachable under.
178 * @param add_remove should the address added (YES) or removed (NO) from the
179 * set of valid addresses?
180 * @param addr one of the addresses of the host
181 * the specific address format depends on the transport
182 * @param addrlen length of the address
183 * @param dest_plugin plugin to use this address with
185 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
189 const char *dest_plugin);
193 * Function that will be called whenever the plugin receives data over
194 * the network and wants to determine how long it should wait until
195 * the next time it reads from the given peer. Note that some plugins
196 * (such as UDP) may not be able to wait (for a particular peer), so
197 * the waiting part is optional. Plugins that can wait should call
198 * this function, sleep the given amount of time, and call it again
199 * (with zero bytes read) UNTIL it returns zero and only then read.
202 * @param peer which peer did we read data from
203 * @param amount_recved number of bytes read (can be zero)
204 * @return how long to wait until reading more from this peer
205 * (to enforce inbound quotas)
207 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
208 const struct GNUNET_PeerIdentity* peer,
209 size_t amount_recved);
213 * Function that returns a HELLO message.
215 typedef const struct GNUNET_MessageHeader *
216 (*GNUNET_TRANSPORT_GetHelloCallback) (void);
220 * The transport service will pass a pointer to a struct
221 * of this type as the first and only argument to the
222 * entry point of each transport plugin.
224 struct GNUNET_TRANSPORT_PluginEnvironment
227 * Configuration to use.
229 const struct GNUNET_CONFIGURATION_Handle *cfg;
232 * Identity of this peer.
234 const struct GNUNET_PeerIdentity *my_identity;
237 * Closure for the various callbacks.
242 * Handle for reporting statistics.
244 struct GNUNET_STATISTICS_Handle *stats;
247 * Function that should be called by the transport plugin
248 * whenever a message is received. If this field is "NULL",
249 * the plugin should load in 'stub' mode and NOT fully
250 * initialize and instead only return an API with the
251 * 'address_pretty_printer', 'address_to_string' and
252 * 'string_to_address' functions.
254 GNUNET_TRANSPORT_PluginReceiveCallback receive;
258 * Function that returns our HELLO.
260 GNUNET_TRANSPORT_GetHelloCallback get_our_hello;
263 * Function that must be called by each plugin to notify the
264 * transport service about the addresses under which the transport
265 * provided by the plugin can be reached.
267 GNUNET_TRANSPORT_AddressNotification notify_address;
270 * Function that must be called by the plugin when a non-NULL
271 * session handle stops being valid (is destroyed).
273 GNUNET_TRANSPORT_SessionEnd session_end;
276 * Function called by the plugin when a new (incoming) session was created
277 * not explicitly created using the the get_session function
279 GNUNET_TRANSPORT_SessionStart session_start;
282 * Function that will be called to figure if an address is an loopback,
283 * LAN, WAN etc. address
285 GNUNET_TRANSPORT_AddressToType get_address_type;
288 * Function that will be called to figure if an address is an loopback,
289 * LAN, WAN etc. address
291 GNUNET_TRANSPORT_UpdateAddressMetrics update_address_metrics;
295 * What is the maximum number of connections that this transport
296 * should allow? Transports that do not have sessions (such as
297 * UDP) can ignore this value.
299 uint32_t max_connections;
305 * Function called by the GNUNET_TRANSPORT_TransmitFunction
306 * upon "completion". In the case that a peer disconnects,
307 * this function must be called for each pending request
308 * (with a 'failure' indication) AFTER notifying the service
309 * about the disconnect event (so that the service won't try
310 * to transmit more messages, believing the connection still
314 * @param target who was the recipient of the message?
315 * @param result GNUNET_OK on success
316 * GNUNET_SYSERR if the target disconnected;
317 * disconnect will ALSO be signalled using
318 * the ReceiveCallback.
319 * @param size_payload bytes of payload from transport service in message
320 * @param size_on_wire bytes required on wire for transmission,
321 * 0 if result == GNUNET_SYSERR
323 typedef void (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
324 const struct GNUNET_PeerIdentity *target,
327 size_t size_on_wire);
330 * The new send function with just the session and no address
332 * Function that can be used by the transport service to transmit
333 * a message using the plugin. Note that in the case of a
334 * peer disconnecting, the continuation MUST be called
335 * prior to the disconnect notification itself. This function
336 * will be called with this peer's HELLO message to initiate
337 * a fresh connection to another peer.
340 * @param session which session must be used
341 * @param msgbuf the message to transmit
342 * @param msgbuf_size number of bytes in 'msgbuf'
343 * @param priority how important is the message (most plugins will
344 * ignore message priority and just FIFO)
345 * @param to how long to wait at most for the transmission (does not
346 * require plugins to discard the message after the timeout,
347 * just advisory for the desired delay; most plugins will ignore
349 * @param cont continuation to call once the message has
350 * been transmitted (or if the transport is ready
351 * for the next transmission call; or if the
352 * peer disconnected...); can be NULL
353 * @param cont_cls closure for cont
354 * @return number of bytes used (on the physical network, with overheads);
355 * -1 on hard errors (i.e. address invalid); 0 is a legal value
356 * and does NOT mean that the message was not transmitted (DV)
358 typedef ssize_t (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
359 struct Session *session,
362 unsigned int priority,
363 struct GNUNET_TIME_Relative to,
364 GNUNET_TRANSPORT_TransmitContinuation cont,
369 * Function that can be called to force a disconnect from the
370 * specified neighbour. This should also cancel all previously
371 * scheduled transmissions. Obviously the transmission may have been
372 * partially completed already, which is OK. The plugin is supposed
373 * to close the connection (if applicable) and no longer call the
374 * transmit continuation(s).
376 * Finally, plugin MUST NOT call the services's receive function to
377 * notify the service that the connection to the specified target was
378 * closed after a getting this call.
381 * @param target peer for which the last transmission is
384 typedef void (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
385 const struct GNUNET_PeerIdentity *target);
389 * Function called by the pretty printer for the resolved address for
390 * each human-readable address obtained.
393 * @param address one of the names for the host, NULL
394 * on the last call to the callback
396 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
397 const char *address);
401 * Convert the transports address to a nice, human-readable
405 * @param type name of the transport that generated the address
406 * @param addr one of the addresses of the host, NULL for the last address
407 * the specific address format depends on the transport
408 * @param addrlen length of the address
409 * @param numeric should (IP) addresses be displayed in numeric form?
410 * @param timeout after how long should we give up?
411 * @param asc function to call on each string
412 * @param asc_cls closure for asc
414 typedef void (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
419 struct GNUNET_TIME_Relative timeout,
420 GNUNET_TRANSPORT_AddressStringCallback asc,
425 * Another peer has suggested an address for this peer and transport
426 * plugin. Check that this could be a valid address. This function
427 * is not expected to 'validate' the address in the sense of trying to
428 * connect to it but simply to see if the binary format is technically
429 * legal for establishing a connection to this peer (and make sure that
430 * the address really corresponds to our network connection/settings
431 * and not some potential man-in-the-middle).
433 * @param addr pointer to the address
434 * @param addrlen length of addr
435 * @return GNUNET_OK if this is a plausible address for this peer
436 * and transport, GNUNET_SYSERR if not
438 typedef int (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
443 * Create a new session to transmit data to the target
444 * This session will used to send data to this peer and the plugin will
445 * notify us by calling the env->session_end function
447 * @param cls the plugin
448 * @param address the hello address
449 * @return the session if the address is valid, NULL otherwise
451 typedef struct Session * (*GNUNET_TRANSPORT_CreateSession) (void *cls,
452 const struct GNUNET_HELLO_Address *address);
456 * Function called for a quick conversion of the binary address to
457 * a numeric address. Note that the caller must not free the
458 * address and that the next call to this function is allowed
459 * to override the address again.
462 * @param addr binary address
463 * @param addr_len length of the address
464 * @return string representing the same address
466 typedef const char *(*GNUNET_TRANSPORT_AddressToString) (void *cls,
471 * Function called to convert a string address to
474 * @param cls closure ('struct Plugin*')
475 * @param addr string address
476 * @param addrlen length of the address including \0 termination
477 * @param buf location to store the buffer
478 * If the function returns GNUNET_SYSERR, its contents are undefined.
479 * @param added length of created address
480 * @return GNUNET_OK on success, GNUNET_SYSERR on failure
482 typedef int (*GNUNET_TRANSPORT_StringToAddress) (void *cls,
490 * Function to obtain the network type for a session
492 * @param cls closure ('struct Plugin*')
493 * @param session the session
494 * @return the network type
496 typedef enum GNUNET_ATS_Network_Type (*GNUNET_TRANSPORT_GetNetworkType) (void *cls,
497 struct Session *session);
501 * Each plugin is required to return a pointer to a struct of this
502 * type as the return value from its entry point.
504 struct GNUNET_TRANSPORT_PluginFunctions
508 * Closure for all of the callbacks.
513 * Function that the transport service will use to transmit data to
514 * another peer. May be NULL for plugins that only support
515 * receiving data. After this call, the plugin call the specified
516 * continuation with success or error before notifying us about the
517 * target having disconnected.
519 GNUNET_TRANSPORT_TransmitFunction send;
522 * Function that can be used to force the plugin to disconnect from
523 * the given peer and cancel all previous transmissions (and their
526 GNUNET_TRANSPORT_DisconnectFunction disconnect;
529 * Function to pretty-print addresses. NOTE: this function is not
530 * yet used by transport-service, but will be used in the future
531 * once the transport-API has been completed.
533 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
536 * Function that will be called to check if a binary address
537 * for this plugin is well-formed and corresponds to an
538 * address for THIS peer (as per our configuration). Naturally,
539 * if absolutely necessary, plugins can be a bit conservative in
540 * their answer, but in general plugins should make sure that the
541 * address does not redirect traffic to a 3rd party that might
542 * try to man-in-the-middle our traffic.
544 GNUNET_TRANSPORT_CheckAddress check_address;
547 * Function that will be called to convert a binary address
548 * to a string (numeric conversion only).
550 GNUNET_TRANSPORT_AddressToString address_to_string;
553 * Function that will be called to convert a string address
554 * to binary (numeric conversion only).
556 GNUNET_TRANSPORT_StringToAddress string_to_address;
559 * Function that will be called tell the plugin to create a session
562 GNUNET_TRANSPORT_CreateSession get_session;
565 * Function to obtain the network type for a session
567 GNUNET_TRANSPORT_GetNetworkType get_network;