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.
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"
48 * Function called by the transport for each received message.
49 * This function should also be called with "NULL" for the
50 * message to signal that the other peer disconnected.
53 * @param peer (claimed) identity of the other peer
54 * @param message the message, NULL if peer was disconnected
55 * @param distance in overlay hops; use 1 unless DV
56 * @param sender_address binary address of the sender (if observed)
57 * @param sender_address_len number of bytes in sender_address
59 typedef void (*GNUNET_TRANSPORT_PluginReceiveCallback) (void *cls,
64 GNUNET_MessageHeader *
67 const char *sender_address,
68 size_t sender_address_len);
72 * Function that will be called for each address the transport
73 * is aware that it might be reachable under.
76 * @param name name of the transport that generated the address
77 * @param addr one of the addresses of the host, NULL for the last address
78 * the specific address format depends on the transport
79 * @param addrlen length of the address
80 * @param expires when should this address automatically expire?
82 typedef void (*GNUNET_TRANSPORT_AddressNotification) (void *cls,
92 * The transport service will pass a pointer to a struct
93 * of this type as the first and only argument to the
94 * entry point of each transport plugin.
96 struct GNUNET_TRANSPORT_PluginEnvironment
99 * Configuration to use.
101 const struct GNUNET_CONFIGURATION_Handle *cfg;
106 struct GNUNET_SCHEDULER_Handle *sched;
109 * Identity of this peer.
111 const struct GNUNET_PeerIdentity *my_identity;
114 * Closure for the various callbacks.
119 * Function that should be called by the transport plugin
120 * whenever a message is received.
122 GNUNET_TRANSPORT_PluginReceiveCallback receive;
125 * Function that must be called by each plugin to notify the
126 * transport service about the addresses under which the transport
127 * provided by the plugin can be reached.
129 GNUNET_TRANSPORT_AddressNotification notify_address;
132 * What is the default quota (in terms of incoming bytes per
133 * ms) for new connections?
135 uint32_t default_quota_in;
138 * What is the maximum number of connections that this transport
139 * should allow? Transports that do not have sessions (such as
140 * UDP) can ignore this value.
142 uint32_t max_connections;
148 * Function called by the GNUNET_TRANSPORT_TransmitFunction
152 * @param target who was the recipient of the message?
153 * @param result GNUNET_OK on success
154 * GNUNET_SYSERR if the target disconnected;
155 * disconnect will ALSO be signalled using
156 * the ReceiveCallback.
159 (*GNUNET_TRANSPORT_TransmitContinuation) (void *cls,
160 const struct GNUNET_PeerIdentity *
165 * Function that can be used by the transport service to transmit
166 * a message using the plugin. Note that in the case of a
167 * peer disconnecting, the continuation MUST be called
168 * prior to the disconnect notification itself. This function
169 * will be called with this peer's HELLO message to initiate
170 * a fresh connection to another peer.
173 * @param target who should receive this message
174 * @param msg the message to transmit
175 * @param priority how important is the message (most plugins will
176 * ignore message priority and just FIFO)
177 * @param timeout how long to wait at most for the transmission (does not
178 * require plugins to discard the message after the timeout,
179 * just advisory for the desired delay; most plugins will ignore
181 * @param addr the address to use (can be NULL if the plugin
182 * is "on its own" (i.e. re-use existing TCP connection))
183 * @param addrlen length of the address in bytes
184 * @param force_address GNUNET_YES if the plugin MUST use the given address,
185 * otherwise the plugin may use other addresses or
186 * existing connections (if available)
187 * @param cont continuation to call once the message has
188 * been transmitted (or if the transport is ready
189 * for the next transmission call; or if the
190 * peer disconnected...); can be NULL
191 * @param cont_cls closure for cont
192 * @return number of bytes used (on the physical network, with overheads);
193 * -1 on hard errors (i.e. address invalid); 0 is a legal value
194 * and does NOT mean that the message was not transmitted (DV)
197 (*GNUNET_TRANSPORT_TransmitFunction) (void *cls,
198 const struct GNUNET_PeerIdentity *
203 struct GNUNET_TIME_Relative timeout,
207 GNUNET_TRANSPORT_TransmitContinuation
208 cont, void *cont_cls);
212 * Function that can be called to force a disconnect from the
213 * specified neighbour. This should also cancel all previously
214 * scheduled transmissions. Obviously the transmission may have been
215 * partially completed already, which is OK. The plugin is supposed
216 * to close the connection (if applicable) and no longer call the
217 * transmit continuation(s).
219 * Finally, plugin MUST NOT call the services's receive function to
220 * notify the service that the connection to the specified target was
221 * closed after a getting this call.
224 * @param target peer for which the last transmission is
228 (*GNUNET_TRANSPORT_DisconnectFunction) (void *cls,
229 const struct GNUNET_PeerIdentity *
234 * Function called by the pretty printer for the resolved address for
235 * each human-readable address obtained.
238 * @param hostname one of the names for the host, NULL
239 * on the last call to the callback
241 typedef void (*GNUNET_TRANSPORT_AddressStringCallback) (void *cls,
242 const char *address);
246 * Convert the transports address to a nice, human-readable
250 * @param name name of the transport that generated the address
251 * @param addr one of the addresses of the host, NULL for the last address
252 * the specific address format depends on the transport
253 * @param addrlen length of the address
254 * @param numeric should (IP) addresses be displayed in numeric form?
255 * @param timeout after how long should we give up?
256 * @param asc function to call on each string
257 * @param asc_cls closure for asc
260 (*GNUNET_TRANSPORT_AddressPrettyPrinter) (void *cls,
265 struct GNUNET_TIME_Relative
267 GNUNET_TRANSPORT_AddressStringCallback
272 * Set a quota for receiving data from the given peer; this is a
273 * per-transport limit. The transport should limit its read/select
274 * calls to stay below the quota (in terms of incoming data).
277 * @param peer the peer for whom the quota is given
278 * @param quota_in quota for receiving/sending data in bytes per ms
281 (*GNUNET_TRANSPORT_SetQuota) (void *cls,
282 const struct GNUNET_PeerIdentity * target,
287 * Another peer has suggested an address for this peer and transport
288 * plugin. Check that this could be a valid address. This function
289 * is not expected to 'validate' the address in the sense of trying to
290 * connect to it but simply to see if the binary format is technically
291 * legal for establishing a connection.
293 * @param addr pointer to the address, may be modified (slightly)
294 * @param addrlen length of addr
295 * @return GNUNET_OK if this is a plausible address for this peer
296 * and transport, GNUNET_SYSERR if not
299 (*GNUNET_TRANSPORT_CheckAddress) (void *cls,
300 void *addr, size_t addrlen);
303 * Each plugin is required to return a pointer to a struct of this
304 * type as the return value from its entry point.
306 struct GNUNET_TRANSPORT_PluginFunctions
310 * Closure for all of the callbacks.
315 * Function that the transport service will use to transmit data to
316 * another peer. May be null for plugins that only support
317 * receiving data. After this call, the plugin call the specified
318 * continuation with success or error before notifying us about the
319 * target having disconnected.
321 GNUNET_TRANSPORT_TransmitFunction send;
324 * Function that can be used to force the plugin to disconnect from
325 * the given peer and cancel all previous transmissions (and their
326 * continuations). Note that if the transport does not have
327 * sessions / persistent connections (for example, UDP), this
328 * function may very well do nothing.
330 GNUNET_TRANSPORT_DisconnectFunction disconnect;
333 * Function to pretty-print addresses. NOTE: this function is not
334 * yet used by transport-service, but will be used in the future
335 * once the transport-API has been completed.
337 GNUNET_TRANSPORT_AddressPrettyPrinter address_pretty_printer;
340 * Function that the transport service can use to try to enforce a
341 * quota for the number of bytes received via this transport.
342 * Transports that can not refuse incoming data (such as UDP)
343 * are free to ignore these calls.
345 GNUNET_TRANSPORT_SetQuota set_receive_quota;
348 * Function that will be called to check if a binary address
349 * for this plugin is well-formed. If clearly needed, patch
350 * up information such as port numbers.
352 GNUNET_TRANSPORT_CheckAddress check_address;