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 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.
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_transport_service.h"
40 * Function called by the transport for each received message.
41 * This function should also be called with "NULL" for the
42 * message to signal that the other peer disconnected.
45 * @param peer (claimed) identity of the other peer
46 * @param message the message, NULL if we only care about
47 * learning about the delay until we should receive again
48 * @param distance in overlay hops; use 1 unless DV (or 0 if message == NULL)
49 * @param sender_address binary address of the sender (if observed)
50 * @param sender_address_len number of bytes in sender_address
51 * @return how long the plugin should wait until receiving more data
52 * (plugins that do not support this, can ignore the return value)
54 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
59 GNUNET_MessageHeader *
62 const char *sender_address,
63 size_t sender_address_len);
67 * Function that will be called for each address the transport
68 * is aware that it might be reachable under.
71 * @param name name of the transport that generated the address
72 * @param addr one of the addresses of the host, NULL for the last address
73 * the specific address format depends on the transport
74 * @param addrlen length of the address
75 * @param expires when should this address automatically expire?
77 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
87 * Function that will be called whenever the plugin receives data over
88 * the network and wants to determine how long it should wait until
89 * the next time it reads from the given peer. Note that some plugins
90 * (such as UDP) may not be able to wait (for a particular peer), so
91 * the waiting part is optional. Plugins that can wait should call
92 * this function, sleep the given amount of time, and call it again
93 * (with zero bytes read) UNTIL it returns zero and only then read.
96 * @param peer which peer did we read data from
97 * @param amount_recved number of bytes read (can be zero)
98 * @return how long to wait until reading more from this peer
99 * (to enforce inbound quotas)
101 typedef struct GNUNET_TIME_Relative (*GNUNET_TRANSPORT_TrafficReport) (void *cls,
103 GNUNET_PeerIdentity *peer,
104 size_t amount_recved);
108 * The transport service will pass a pointer to a struct
109 * of this type as the first and only argument to the
110 * entry point of each transport plugin.
112 struct GNUNET_TRANSPORT_PluginEnvironment
115 * Configuration to use.
117 const struct GNUNET_CONFIGURATION_Handle *cfg;
122 struct GNUNET_SCHEDULER_Handle *sched;
125 * Identity of this peer.
127 const struct GNUNET_PeerIdentity *my_identity;
130 * Closure for the various callbacks.
135 * Function that should be called by the transport plugin
136 * whenever a message is received.
138 GNUNET_TRANSPORT_PluginReceiveCallback receive;
141 * Function that must be called by each plugin to notify the
142 * transport service about the addresses under which the transport
143 * provided by the plugin can be reached.
145 GNUNET_TRANSPORT_AddressNotification notify_address;
148 * Inform service about traffic received, get information
149 * about when we might be willing to receive more.
151 GNUNET_TRANSPORT_TrafficReport traffic_report;
154 * What is the maximum number of connections that this transport
155 * should allow? Transports that do not have sessions (such as
156 * UDP) can ignore this value.
158 uint32_t max_connections;
164 * Function called by the GNUNET_TRANSPORT_TransmitFunction
168 * @param target who was the recipient of the message?
169 * @param result GNUNET_OK on success
170 * GNUNET_SYSERR if the target disconnected;
171 * disconnect will ALSO be signalled using
172 * the ReceiveCallback.
175 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
176 const struct GNUNET_PeerIdentity *
181 * Function that can be used by the transport service to transmit
182 * a message using the plugin. Note that in the case of a
183 * peer disconnecting, the continuation MUST be called
184 * prior to the disconnect notification itself. This function
185 * will be called with this peer's HELLO message to initiate
186 * a fresh connection to another peer.
189 * @param target who should receive this message
190 * @param msgbuf the message to transmit
191 * @param msgbuf_size number of bytes in 'msgbuf'
192 * @param priority how important is the message (most plugins will
193 * ignore message priority and just FIFO)
194 * @param timeout how long to wait at most for the transmission (does not
195 * require plugins to discard the message after the timeout,
196 * just advisory for the desired delay; most plugins will ignore
198 * @param addr the address to use (can be NULL if the plugin
199 * is "on its own" (i.e. re-use existing TCP connection))
200 * @param addrlen length of the address in bytes
201 * @param force_address GNUNET_YES if the plugin MUST use the given address,
202 * otherwise the plugin may use other addresses or
203 * existing connections (if available)
204 * @param cont continuation to call once the message has
205 * been transmitted (or if the transport is ready
206 * for the next transmission call; or if the
207 * peer disconnected...); can be NULL
208 * @param cont_cls closure for cont
209 * @return number of bytes used (on the physical network, with overheads);
210 * -1 on hard errors (i.e. address invalid); 0 is a legal value
211 * and does NOT mean that the message was not transmitted (DV)
214 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
215 const struct GNUNET_PeerIdentity *
220 struct GNUNET_TIME_Relative timeout,
224 GNUNET_TRANSPORT_TransmitContinuation
225 cont, void *cont_cls);
229 * Function that can be called to force a disconnect from the
230 * specified neighbour. This should also cancel all previously
231 * scheduled transmissions. Obviously the transmission may have been
232 * partially completed already, which is OK. The plugin is supposed
233 * to close the connection (if applicable) and no longer call the
234 * transmit continuation(s).
236 * Finally, plugin MUST NOT call the services's receive function to
237 * notify the service that the connection to the specified target was
238 * closed after a getting this call.
241 * @param target peer for which the last transmission is
245 (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
246 const struct GNUNET_PeerIdentity *
251 * Function called by the pretty printer for the resolved address for
252 * each human-readable address obtained.
255 * @param hostname one of the names for the host, NULL
256 * on the last call to the callback
258 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
259 const char *address);
263 * Convert the transports address to a nice, human-readable
267 * @param name name of the transport that generated the address
268 * @param addr one of the addresses of the host, NULL for the last address
269 * the specific address format depends on the transport
270 * @param addrlen length of the address
271 * @param numeric should (IP) addresses be displayed in numeric form?
272 * @param timeout after how long should we give up?
273 * @param asc function to call on each string
274 * @param asc_cls closure for asc
277 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
282 struct GNUNET_TIME_Relative
284 GNUNET_TRANSPORT_AddressStringCallback
289 * Another peer has suggested an address for this peer and transport
290 * plugin. Check that this could be a valid address. This function
291 * is not expected to 'validate' the address in the sense of trying to
292 * connect to it but simply to see if the binary format is technically
293 * legal for establishing a connection.
295 * @param addr pointer to the address, may be modified (slightly)
296 * @param addrlen length of addr
297 * @return GNUNET_OK if this is a plausible address for this peer
298 * and transport, GNUNET_SYSERR if not
301 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
302 void *addr, size_t addrlen);
305 * Each plugin is required to return a pointer to a struct of this
306 * type as the return value from its entry point.
308 struct GNUNET_TRANSPORT_PluginFunctions
312 * Closure for all of the callbacks.
317 * Function that the transport service will use to transmit data to
318 * another peer. May be null for plugins that only support
319 * receiving data. After this call, the plugin call the specified
320 * continuation with success or error before notifying us about the
321 * target having disconnected.
323 GNUNET_TRANSPORT_TransmitFunction send;
326 * Function that can be used to force the plugin to disconnect from
327 * the given peer and cancel all previous transmissions (and their
328 * continuations). Note that if the transport does not have
329 * sessions / persistent connections (for example, UDP), this
330 * function may very well do nothing.
332 GNUNET_TRANSPORT_DisconnectFunction disconnect;
335 * Function to pretty-print addresses. NOTE: this function is not
336 * yet used by transport-service, but will be used in the future
337 * once the transport-API has been completed.
339 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
342 * Function that will be called to check if a binary address
343 * for this plugin is well-formed. If clearly needed, patch
344 * up information such as port numbers.
346 GNUNET_TRANSPORT_CheckAddress check_address;