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17 * @author Christian Grothoff
19 * Helper library for handling HELLOs
21 * @defgroup hello Hello library
22 * Helper library for handling HELLOs
24 * @see [Documentation](https://gnunet.org/gnunets-hostlist-subsystem)
29 #ifndef GNUNET_HELLO_LIB_H
30 #define GNUNET_HELLO_LIB_H
35 #if 0 /* keep Emacsens' auto-indent happy */
40 #include "gnunet_util_lib.h"
44 * Prefix that every HELLO URI must start with.
46 #define GNUNET_HELLO_URI_PREFIX "gnunet://hello/"
49 * Prefix that every FRIEND HELLO URI must start with.
51 #define GNUNET_FRIEND_HELLO_URI_PREFIX "gnunet://friend-hello/"
54 * Separator used in HELLO URI
56 #define GNUNET_HELLO_URI_SEP '+'
60 * Additional local information about an address
62 * These information are only valid for the local peer and are not serialized
63 * when a #GNUNET_HELLO_Message is created
65 enum GNUNET_HELLO_AddressInfo
68 * No additional information
70 GNUNET_HELLO_ADDRESS_INFO_NONE = 0,
73 * This is an inbound address and cannot be used to initiate an outbound
74 * connection to another peer
76 GNUNET_HELLO_ADDRESS_INFO_INBOUND = 1
81 * An address for communicating with a peer. We frequently
82 * need this tuple and the components cannot really be
83 * separated. This is NOT the format that would be used
86 struct GNUNET_HELLO_Address
90 * For which peer is this an address?
92 struct GNUNET_PeerIdentity peer;
95 * Name of the transport plugin enabling the communication using
98 const char *transport_name;
101 * Binary representation of the address (plugin-specific).
106 * Number of bytes in @e address.
108 size_t address_length;
111 * Extended information about address
113 * This field contains additional #GNUNET_HELLO_AddressInfo flags e.g.
114 * to indicate an address is inbound and cannot be used to initiate an
115 * outbound connection.
117 * These information are only valid for the local peer and are not serialized
118 * when a #GNUNET_HELLO_Message is created
120 enum GNUNET_HELLO_AddressInfo local_info;
126 * Allocate an address struct.
128 * @param peer the peer
129 * @param transport_name plugin name
130 * @param address binary address
131 * @param address_length number of bytes in @a address
132 * @param local_info additional local information for the address
133 * @return the address struct
135 struct GNUNET_HELLO_Address *
136 GNUNET_HELLO_address_allocate (const struct GNUNET_PeerIdentity *peer,
137 const char *transport_name,
139 size_t address_length,
140 enum GNUNET_HELLO_AddressInfo local_info);
144 * Copy an address struct.
146 * @param address address to copy
147 * @return a copy of the address struct
149 struct GNUNET_HELLO_Address *
150 GNUNET_HELLO_address_copy (const struct GNUNET_HELLO_Address *address);
154 * Compare two addresses. Does NOT compare the peer identity,
155 * that is assumed already to match!
157 * @param a1 first address
158 * @param a2 second address
159 * @return 0 if the addresses are equal, -1 if @a a1< @a a2, 1 if @a a1> @a a2.
162 GNUNET_HELLO_address_cmp (const struct GNUNET_HELLO_Address *a1,
163 const struct GNUNET_HELLO_Address *a2);
167 * Get the size of an address struct.
169 * @param address address
173 GNUNET_HELLO_address_get_size (const struct GNUNET_HELLO_Address *address);
177 * Check if an address has a local option set
179 * @param address the address to check
180 * @param option the respective option to check for
181 * @return #GNUNET_YES or #GNUNET_NO
184 GNUNET_HELLO_address_check_option (const struct GNUNET_HELLO_Address *address,
185 enum GNUNET_HELLO_AddressInfo option);
191 * @param addr address to free
193 #define GNUNET_HELLO_address_free(addr) GNUNET_free(addr)
196 GNUNET_NETWORK_STRUCT_BEGIN
199 * A HELLO message is used to exchange information about
200 * transports with other peers. This struct is always
201 * followed by the actual network addresses which have
204 * 1) transport-name (0-terminated)
205 * 2) address-length (uint16_t, network byte order; possibly
207 * 3) address expiration (`struct GNUNET_TIME_AbsoluteNBO`); possibly
209 * 4) address (address-length bytes; possibly unaligned!)
211 struct GNUNET_HELLO_Message
214 * Type will be #GNUNET_MESSAGE_TYPE_HELLO.
216 struct GNUNET_MessageHeader header;
219 * Use in F2F mode: Do not gossip this HELLO message
221 uint32_t friend_only GNUNET_PACKED;
224 * The public key of the peer.
226 struct GNUNET_CRYPTO_EddsaPublicKey publicKey;
229 GNUNET_NETWORK_STRUCT_END
236 * @param h HELLO Message to test
237 * @return #GNUNET_YES for friend-only or #GNUNET_NO otherwise
240 GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h);
244 * Copy the given address information into
245 * the given buffer using the format of HELLOs.
247 * @param address address to add
248 * @param expiration expiration for the address
249 * @param target where to copy the address
250 * @param max maximum number of bytes to copy to @a target
251 * @return number of bytes copied, 0 if
252 * the target buffer was not big enough.
255 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
256 struct GNUNET_TIME_Absolute expiration,
262 * Callback function used to fill a buffer of max bytes with a list of
263 * addresses in the format used by HELLOs. Should use
264 * #GNUNET_HELLO_add_address() as a helper function.
267 * @param max maximum number of bytes that can be written to @a buf
268 * @param buf where to write the address information
269 * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
270 * end of the iteration.
273 (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
279 * Construct a HELLO message given the public key,
280 * expiration time and an iterator that spews the
281 * transport addresses.
283 * If friend only is set to #GNUNET_YES we create a FRIEND_HELLO which
284 * will not be gossiped to other peers.
286 * @param public_key public key to include in the HELLO
287 * @param addrgen callback to invoke to get addresses
288 * @param addrgen_cls closure for @a addrgen
289 * @param friend_only should the returned HELLO be only visible to friends?
290 * @return the hello message
292 struct GNUNET_HELLO_Message *
293 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
294 GNUNET_HELLO_GenerateAddressListCallback addrgen,
300 * Return the size of the given HELLO message.
302 * @param hello to inspect
303 * @return the size, 0 if HELLO is invalid
306 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
310 * Construct a HELLO message by merging the
311 * addresses in two existing HELLOs (which
312 * must be for the same peer).
314 * @param h1 first HELLO message
315 * @param h2 the second HELLO message
316 * @return the combined hello message
318 struct GNUNET_HELLO_Message *
319 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
320 const struct GNUNET_HELLO_Message *h2);
324 * Test if two HELLO messages contain the same addresses.
325 * If they only differ in expiration time, the lowest
326 * expiration time larger than 'now' where they differ
329 * @param h1 first HELLO message
330 * @param h2 the second HELLO message
331 * @param now time to use for deciding which addresses have
332 * expired and should not be considered at all
333 * @return absolute time forever if the two HELLOs are
334 * totally identical; smallest timestamp >= now if
335 * they only differ in timestamps;
336 * zero if the some addresses with expirations >= now
337 * do not match at all
339 struct GNUNET_TIME_Absolute
340 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
341 const struct GNUNET_HELLO_Message *h2,
342 struct GNUNET_TIME_Absolute now);
346 * Iterator callback to go over all addresses.
349 * @param address the address
350 * @param expiration expiration time
351 * @return #GNUNET_OK to keep the address,
352 * #GNUNET_NO to delete it from the HELLO
353 * #GNUNET_SYSERR to stop iterating (but keep current address)
356 (*GNUNET_HELLO_AddressIterator) (void *cls,
357 const struct GNUNET_HELLO_Address *address,
358 struct GNUNET_TIME_Absolute expiration);
362 * When does the last address in the given HELLO expire?
364 * @param msg HELLO to inspect
365 * @return time the last address expires, 0 if there are no addresses in the HELLO
367 struct GNUNET_TIME_Absolute
368 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
372 * Iterate over all of the addresses in the HELLO.
374 * @param msg HELLO to iterate over; client does not need to
375 * have verified that msg is well-formed (beyond starting
376 * with a GNUNET_MessageHeader of the right type).
377 * @param return_modified if a modified copy should be returned,
378 * otherwise NULL will be returned
379 * @param it iterator to call on each address
380 * @param it_cls closure for @a it
381 * @return the modified HELLO or NULL
383 struct GNUNET_HELLO_Message *
384 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
386 GNUNET_HELLO_AddressIterator it, void *it_cls);
390 * Iterate over addresses in @a new_hello that are NOT already present
391 * in @a old_hello. Note that if the address is present in @a old_hello
392 * but the expiration time in @a new_hello is more recent, the
393 * iterator is also called.
395 * @param new_hello a HELLO message
396 * @param old_hello a HELLO message
397 * @param expiration_limit ignore addresses in old_hello
398 * that expired before the given time stamp
399 * @param it iterator to call on each address
400 * @param it_cls closure for @a it
403 GNUNET_HELLO_iterate_new_addresses (const struct GNUNET_HELLO_Message *new_hello,
404 const struct GNUNET_HELLO_Message *old_hello,
405 struct GNUNET_TIME_Absolute expiration_limit,
406 GNUNET_HELLO_AddressIterator it,
411 * Get the peer identity from a HELLO message.
413 * @param hello the hello message
414 * @param peer where to store the peer's identity
415 * @return #GNUNET_SYSERR if the HELLO was malformed
418 GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
419 struct GNUNET_PeerIdentity *peer);
423 * Get the header from a HELLO message, used so other code
424 * can correctly send HELLO messages.
426 * @param hello the hello message
428 * @return header or NULL if the HELLO was malformed
430 struct GNUNET_MessageHeader *
431 GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello);
435 * Helper function to load/access transport plugins.
436 * FIXME: pass closure!
438 * @param name name of the transport plugin to load
439 * @return NULL if a plugin with name @a name is not known/loadable
441 typedef struct GNUNET_TRANSPORT_PluginFunctions *
442 (*GNUNET_HELLO_TransportPluginsFind) (const char *name);
446 * Compose a hello URI string from a hello message.
448 * @param hello Hello message
449 * @param plugins_find Function to find transport plugins by name
450 * @return Hello URI string
453 GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
454 GNUNET_HELLO_TransportPluginsFind plugins_find);
458 * Parse a hello URI string to a hello message.
460 * @param uri URI string to parse
461 * @param pubkey Pointer to struct where public key is parsed
462 * @param hello Pointer to struct where hello message is parsed
463 * @param plugins_find Function to find transport plugins by name
464 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the URI was invalid, #GNUNET_NO on other errors
467 GNUNET_HELLO_parse_uri (const char *uri,
468 struct GNUNET_CRYPTO_EddsaPublicKey *pubkey,
469 struct GNUNET_HELLO_Message **hello,
470 GNUNET_HELLO_TransportPluginsFind plugins_find);
473 #if 0 /* keep Emacsens' auto-indent happy */
480 /* ifndef GNUNET_HELLO_LIB_H */
483 /** @} */ /* end of group */
485 /* end of gnunet_hello_lib.h */