2 This file is part of GNUnet.
3 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2010, 2011 GNUnet e.V.
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., 51 Franklin Street, Fifth Floor,
18 Boston, MA 02110-1301, USA.
22 * @author Christian Grothoff
24 * Helper library for handling HELLOs
26 * @defgroup hello Hello library
27 * Helper library for handling HELLOs
29 * @see [Documentation](https://gnunet.org/gnunets-hostlist-subsystem)
34 #ifndef GNUNET_HELLO_LIB_H
35 #define GNUNET_HELLO_LIB_H
40 #if 0 /* keep Emacsens' auto-indent happy */
45 #include "gnunet_util_lib.h"
49 * Prefix that every HELLO URI must start with.
51 #define GNUNET_HELLO_URI_PREFIX "gnunet://hello/"
54 * Prefix that every FRIEND HELLO URI must start with.
56 #define GNUNET_FRIEND_HELLO_URI_PREFIX "gnunet://friend-hello/"
59 * Separator used in HELLO URI
61 #define GNUNET_HELLO_URI_SEP '+'
65 * Additional local information about an address
67 * These information are only valid for the local peer and are not serialized
68 * when a #GNUNET_HELLO_Message is created
70 enum GNUNET_HELLO_AddressInfo
73 * No additional information
75 GNUNET_HELLO_ADDRESS_INFO_NONE = 0,
78 * This is an inbound address and cannot be used to initiate an outbound
79 * connection to another peer
81 GNUNET_HELLO_ADDRESS_INFO_INBOUND = 1
86 * An address for communicating with a peer. We frequently
87 * need this tuple and the components cannot really be
88 * separated. This is NOT the format that would be used
91 struct GNUNET_HELLO_Address
95 * For which peer is this an address?
97 struct GNUNET_PeerIdentity peer;
100 * Name of the transport plugin enabling the communication using
103 const char *transport_name;
106 * Binary representation of the address (plugin-specific).
111 * Number of bytes in @e address.
113 size_t address_length;
116 * Extended information about address
118 * This field contains additional #GNUNET_HELLO_AddressInfo flags e.g.
119 * to indicate an address is inbound and cannot be used to initiate an
120 * outbound connection.
122 * These information are only valid for the local peer and are not serialized
123 * when a #GNUNET_HELLO_Message is created
125 enum GNUNET_HELLO_AddressInfo local_info;
131 * Allocate an address struct.
133 * @param peer the peer
134 * @param transport_name plugin name
135 * @param address binary address
136 * @param address_length number of bytes in @a address
137 * @param local_info additional local information for the address
138 * @return the address struct
140 struct GNUNET_HELLO_Address *
141 GNUNET_HELLO_address_allocate (const struct GNUNET_PeerIdentity *peer,
142 const char *transport_name,
144 size_t address_length,
145 enum GNUNET_HELLO_AddressInfo local_info);
149 * Copy an address struct.
151 * @param address address to copy
152 * @return a copy of the address struct
154 struct GNUNET_HELLO_Address *
155 GNUNET_HELLO_address_copy (const struct GNUNET_HELLO_Address *address);
159 * Compare two addresses. Does NOT compare the peer identity,
160 * that is assumed already to match!
162 * @param a1 first address
163 * @param a2 second address
164 * @return 0 if the addresses are equal, -1 if @a a1< @a a2, 1 if @a a1> @a a2.
167 GNUNET_HELLO_address_cmp (const struct GNUNET_HELLO_Address *a1,
168 const struct GNUNET_HELLO_Address *a2);
172 * Get the size of an address struct.
174 * @param address address
178 GNUNET_HELLO_address_get_size (const struct GNUNET_HELLO_Address *address);
182 * Check if an address has a local option set
184 * @param address the address to check
185 * @param option the respective option to check for
186 * @return #GNUNET_YES or #GNUNET_NO
189 GNUNET_HELLO_address_check_option (const struct GNUNET_HELLO_Address *address,
190 enum GNUNET_HELLO_AddressInfo option);
196 * @param addr address to free
198 #define GNUNET_HELLO_address_free(addr) GNUNET_free(addr)
202 * A HELLO message is used to exchange information about
203 * transports with other peers. This struct is guaranteed
204 * to start with a `struct GNUNET_MessageHeader`, everything else
205 * should be internal to the HELLO library.
207 struct GNUNET_HELLO_Message;
213 * @param h HELLO Message to test
214 * @return #GNUNET_YES for friend-only or #GNUNET_NO otherwise
217 GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h);
221 * Copy the given address information into
222 * the given buffer using the format of HELLOs.
224 * @param address address to add
225 * @param expiration expiration for the address
226 * @param target where to copy the address
227 * @param max maximum number of bytes to copy to @a target
228 * @return number of bytes copied, 0 if
229 * the target buffer was not big enough.
232 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
233 struct GNUNET_TIME_Absolute expiration,
239 * Callback function used to fill a buffer of max bytes with a list of
240 * addresses in the format used by HELLOs. Should use
241 * #GNUNET_HELLO_add_address() as a helper function.
244 * @param max maximum number of bytes that can be written to @a buf
245 * @param buf where to write the address information
246 * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
247 * end of the iteration.
250 (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
256 * Construct a HELLO message given the public key,
257 * expiration time and an iterator that spews the
258 * transport addresses.
260 * If friend only is set to #GNUNET_YES we create a FRIEND_HELLO which
261 * will not be gossiped to other peers.
263 * @param public_key public key to include in the HELLO
264 * @param addrgen callback to invoke to get addresses
265 * @param addrgen_cls closure for @a addrgen
266 * @param friend_only should the returned HELLO be only visible to friends?
267 * @return the hello message
269 struct GNUNET_HELLO_Message *
270 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
271 GNUNET_HELLO_GenerateAddressListCallback addrgen,
277 * Return the size of the given HELLO message.
279 * @param hello to inspect
280 * @return the size, 0 if HELLO is invalid
283 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
287 * Construct a HELLO message by merging the
288 * addresses in two existing HELLOs (which
289 * must be for the same peer).
291 * @param h1 first HELLO message
292 * @param h2 the second HELLO message
293 * @return the combined hello message
295 struct GNUNET_HELLO_Message *
296 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
297 const struct GNUNET_HELLO_Message *h2);
301 * Test if two HELLO messages contain the same addresses.
302 * If they only differ in expiration time, the lowest
303 * expiration time larger than 'now' where they differ
306 * @param h1 first HELLO message
307 * @param h2 the second HELLO message
308 * @param now time to use for deciding which addresses have
309 * expired and should not be considered at all
310 * @return absolute time forever if the two HELLOs are
311 * totally identical; smallest timestamp >= now if
312 * they only differ in timestamps;
313 * zero if the some addresses with expirations >= now
314 * do not match at all
316 struct GNUNET_TIME_Absolute
317 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
318 const struct GNUNET_HELLO_Message *h2,
319 struct GNUNET_TIME_Absolute now);
323 * Iterator callback to go over all addresses.
326 * @param address the address
327 * @param expiration expiration time
328 * @return #GNUNET_OK to keep the address,
329 * #GNUNET_NO to delete it from the HELLO
330 * #GNUNET_SYSERR to stop iterating (but keep current address)
333 (*GNUNET_HELLO_AddressIterator) (void *cls,
334 const struct GNUNET_HELLO_Address *address,
335 struct GNUNET_TIME_Absolute expiration);
339 * When does the last address in the given HELLO expire?
341 * @param msg HELLO to inspect
342 * @return time the last address expires, 0 if there are no addresses in the HELLO
344 struct GNUNET_TIME_Absolute
345 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
349 * Iterate over all of the addresses in the HELLO.
351 * @param msg HELLO to iterate over; client does not need to
352 * have verified that msg is well-formed (beyond starting
353 * with a GNUNET_MessageHeader of the right type).
354 * @param return_modified if a modified copy should be returned,
355 * otherwise NULL will be returned
356 * @param it iterator to call on each address
357 * @param it_cls closure for @a it
358 * @return the modified HELLO or NULL
360 struct GNUNET_HELLO_Message *
361 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
363 GNUNET_HELLO_AddressIterator it, void *it_cls);
367 * Iterate over addresses in @a new_hello that are NOT already present
368 * in @a old_hello. Note that if the address is present in @a old_hello
369 * but the expiration time in @a new_hello is more recent, the
370 * iterator is also called.
372 * @param new_hello a HELLO message
373 * @param old_hello a HELLO message
374 * @param expiration_limit ignore addresses in old_hello
375 * that expired before the given time stamp
376 * @param it iterator to call on each address
377 * @param it_cls closure for @a it
380 GNUNET_HELLO_iterate_new_addresses (const struct GNUNET_HELLO_Message *new_hello,
381 const struct GNUNET_HELLO_Message *old_hello,
382 struct GNUNET_TIME_Absolute expiration_limit,
383 GNUNET_HELLO_AddressIterator it,
388 * Get the peer identity from a HELLO message.
390 * @param hello the hello message
391 * @param peer where to store the peer's identity
392 * @return #GNUNET_SYSERR if the HELLO was malformed
395 GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
396 struct GNUNET_PeerIdentity *peer);
400 * Get the header from a HELLO message, used so other code
401 * can correctly send HELLO messages.
403 * @param hello the hello message
405 * @return header or NULL if the HELLO was malformed
407 struct GNUNET_MessageHeader *
408 GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello);
412 * Helper function to load/access transport plugins.
413 * FIXME: pass closure!
415 * @param name name of the transport plugin to load
416 * @return NULL if a plugin with name @a name is not known/loadable
418 typedef struct GNUNET_TRANSPORT_PluginFunctions *
419 (*GNUNET_HELLO_TransportPluginsFind) (const char *name);
423 * Compose a hello URI string from a hello message.
425 * @param hello Hello message
426 * @param plugins_find Function to find transport plugins by name
427 * @return Hello URI string
430 GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
431 GNUNET_HELLO_TransportPluginsFind plugins_find);
435 * Parse a hello URI string to a hello message.
437 * @param uri URI string to parse
438 * @param pubkey Pointer to struct where public key is parsed
439 * @param hello Pointer to struct where hello message is parsed
440 * @param plugins_find Function to find transport plugins by name
441 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the URI was invalid, #GNUNET_NO on other errors
444 GNUNET_HELLO_parse_uri (const char *uri,
445 struct GNUNET_CRYPTO_EddsaPublicKey *pubkey,
446 struct GNUNET_HELLO_Message **hello,
447 GNUNET_HELLO_TransportPluginsFind plugins_find);
450 #if 0 /* keep Emacsens' auto-indent happy */
457 /* ifndef GNUNET_HELLO_LIB_H */
460 /** @} */ /* end of group */
462 /* end of gnunet_hello_lib.h */