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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)
201 GNUNET_NETWORK_STRUCT_BEGIN
204 * A HELLO message is used to exchange information about
205 * transports with other peers. This struct is always
206 * followed by the actual network addresses which have
209 * 1) transport-name (0-terminated)
210 * 2) address-length (uint16_t, network byte order; possibly
212 * 3) address expiration (`struct GNUNET_TIME_AbsoluteNBO`); possibly
214 * 4) address (address-length bytes; possibly unaligned!)
216 struct GNUNET_HELLO_Message
219 * Type will be #GNUNET_MESSAGE_TYPE_HELLO.
221 struct GNUNET_MessageHeader header;
224 * Use in F2F mode: Do not gossip this HELLO message
226 uint32_t friend_only GNUNET_PACKED;
229 * The public key of the peer.
231 struct GNUNET_CRYPTO_EddsaPublicKey publicKey;
234 GNUNET_NETWORK_STRUCT_END
241 * @param h HELLO Message to test
242 * @return #GNUNET_YES for friend-only or #GNUNET_NO otherwise
245 GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h);
249 * Copy the given address information into
250 * the given buffer using the format of HELLOs.
252 * @param address address to add
253 * @param expiration expiration for the address
254 * @param target where to copy the address
255 * @param max maximum number of bytes to copy to @a target
256 * @return number of bytes copied, 0 if
257 * the target buffer was not big enough.
260 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
261 struct GNUNET_TIME_Absolute expiration,
267 * Callback function used to fill a buffer of max bytes with a list of
268 * addresses in the format used by HELLOs. Should use
269 * #GNUNET_HELLO_add_address() as a helper function.
272 * @param max maximum number of bytes that can be written to @a buf
273 * @param buf where to write the address information
274 * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
275 * end of the iteration.
278 (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
284 * Construct a HELLO message given the public key,
285 * expiration time and an iterator that spews the
286 * transport addresses.
288 * If friend only is set to #GNUNET_YES we create a FRIEND_HELLO which
289 * will not be gossiped to other peers.
291 * @param public_key public key to include in the HELLO
292 * @param addrgen callback to invoke to get addresses
293 * @param addrgen_cls closure for @a addrgen
294 * @param friend_only should the returned HELLO be only visible to friends?
295 * @return the hello message
297 struct GNUNET_HELLO_Message *
298 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
299 GNUNET_HELLO_GenerateAddressListCallback addrgen,
305 * Return the size of the given HELLO message.
307 * @param hello to inspect
308 * @return the size, 0 if HELLO is invalid
311 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
315 * Construct a HELLO message by merging the
316 * addresses in two existing HELLOs (which
317 * must be for the same peer).
319 * @param h1 first HELLO message
320 * @param h2 the second HELLO message
321 * @return the combined hello message
323 struct GNUNET_HELLO_Message *
324 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
325 const struct GNUNET_HELLO_Message *h2);
329 * Test if two HELLO messages contain the same addresses.
330 * If they only differ in expiration time, the lowest
331 * expiration time larger than 'now' where they differ
334 * @param h1 first HELLO message
335 * @param h2 the second HELLO message
336 * @param now time to use for deciding which addresses have
337 * expired and should not be considered at all
338 * @return absolute time forever if the two HELLOs are
339 * totally identical; smallest timestamp >= now if
340 * they only differ in timestamps;
341 * zero if the some addresses with expirations >= now
342 * do not match at all
344 struct GNUNET_TIME_Absolute
345 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
346 const struct GNUNET_HELLO_Message *h2,
347 struct GNUNET_TIME_Absolute now);
351 * Iterator callback to go over all addresses.
354 * @param address the address
355 * @param expiration expiration time
356 * @return #GNUNET_OK to keep the address,
357 * #GNUNET_NO to delete it from the HELLO
358 * #GNUNET_SYSERR to stop iterating (but keep current address)
361 (*GNUNET_HELLO_AddressIterator) (void *cls,
362 const struct GNUNET_HELLO_Address *address,
363 struct GNUNET_TIME_Absolute expiration);
367 * When does the last address in the given HELLO expire?
369 * @param msg HELLO to inspect
370 * @return time the last address expires, 0 if there are no addresses in the HELLO
372 struct GNUNET_TIME_Absolute
373 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
377 * Iterate over all of the addresses in the HELLO.
379 * @param msg HELLO to iterate over; client does not need to
380 * have verified that msg is well-formed (beyond starting
381 * with a GNUNET_MessageHeader of the right type).
382 * @param return_modified if a modified copy should be returned,
383 * otherwise NULL will be returned
384 * @param it iterator to call on each address
385 * @param it_cls closure for @a it
386 * @return the modified HELLO or NULL
388 struct GNUNET_HELLO_Message *
389 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
391 GNUNET_HELLO_AddressIterator it, void *it_cls);
395 * Iterate over addresses in @a new_hello that are NOT already present
396 * in @a old_hello. Note that if the address is present in @a old_hello
397 * but the expiration time in @a new_hello is more recent, the
398 * iterator is also called.
400 * @param new_hello a HELLO message
401 * @param old_hello a HELLO message
402 * @param expiration_limit ignore addresses in old_hello
403 * that expired before the given time stamp
404 * @param it iterator to call on each address
405 * @param it_cls closure for @a it
408 GNUNET_HELLO_iterate_new_addresses (const struct GNUNET_HELLO_Message *new_hello,
409 const struct GNUNET_HELLO_Message *old_hello,
410 struct GNUNET_TIME_Absolute expiration_limit,
411 GNUNET_HELLO_AddressIterator it,
416 * Get the peer identity from a HELLO message.
418 * @param hello the hello message
419 * @param peer where to store the peer's identity
420 * @return #GNUNET_SYSERR if the HELLO was malformed
423 GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
424 struct GNUNET_PeerIdentity *peer);
428 * Get the header from a HELLO message, used so other code
429 * can correctly send HELLO messages.
431 * @param hello the hello message
433 * @return header or NULL if the HELLO was malformed
435 struct GNUNET_MessageHeader *
436 GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello);
440 * Helper function to load/access transport plugins.
441 * FIXME: pass closure!
443 * @param name name of the transport plugin to load
444 * @return NULL if a plugin with name @a name is not known/loadable
446 typedef struct GNUNET_TRANSPORT_PluginFunctions *
447 (*GNUNET_HELLO_TransportPluginsFind) (const char *name);
451 * Compose a hello URI string from a hello message.
453 * @param hello Hello message
454 * @param plugins_find Function to find transport plugins by name
455 * @return Hello URI string
458 GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
459 GNUNET_HELLO_TransportPluginsFind plugins_find);
463 * Parse a hello URI string to a hello message.
465 * @param uri URI string to parse
466 * @param pubkey Pointer to struct where public key is parsed
467 * @param hello Pointer to struct where hello message is parsed
468 * @param plugins_find Function to find transport plugins by name
469 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the URI was invalid, #GNUNET_NO on other errors
472 GNUNET_HELLO_parse_uri (const char *uri,
473 struct GNUNET_CRYPTO_EddsaPublicKey *pubkey,
474 struct GNUNET_HELLO_Message **hello,
475 GNUNET_HELLO_TransportPluginsFind plugins_find);
478 #if 0 /* keep Emacsens' auto-indent happy */
485 /* ifndef GNUNET_HELLO_LIB_H */
488 /** @} */ /* end of group */
490 /* end of gnunet_hello_lib.h */