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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
39 #if 0 /* keep Emacsens' auto-indent happy */
44 #include "gnunet_util_lib.h"
47 * Prefix that every HELLO URI must start with.
49 #define GNUNET_HELLO_URI_PREFIX "gnunet://hello/"
52 * Prefix that every FRIEND HELLO URI must start with.
54 #define GNUNET_FRIEND_HELLO_URI_PREFIX "gnunet://friend-hello/"
57 * Separator used in HELLO URI
59 #define GNUNET_HELLO_URI_SEP '+'
63 * Additional local information about an address
65 * These information are only valid for the local peer and are not serialized
66 * when a #GNUNET_HELLO_Message is created
68 enum GNUNET_HELLO_AddressInfo
71 * No additional information
73 GNUNET_HELLO_ADDRESS_INFO_NONE = 0,
76 * This is an inbound address and cannot be used to initiate an outbound
77 * connection to another peer
79 GNUNET_HELLO_ADDRESS_INFO_INBOUND = 1
84 * An address for communicating with a peer. We frequently
85 * need this tuple and the components cannot really be
86 * separated. This is NOT the format that would be used
89 struct GNUNET_HELLO_Address
92 * For which peer is this an address?
94 struct GNUNET_PeerIdentity peer;
97 * Name of the transport plugin enabling the communication using
100 const char *transport_name;
103 * Binary representation of the address (plugin-specific).
108 * Number of bytes in @e address.
110 size_t address_length;
113 * Extended information about address
115 * This field contains additional #GNUNET_HELLO_AddressInfo flags e.g.
116 * to indicate an address is inbound and cannot be used to initiate an
117 * outbound connection.
119 * These information are only valid for the local peer and are not serialized
120 * when a #GNUNET_HELLO_Message is created
122 enum GNUNET_HELLO_AddressInfo local_info;
127 * Allocate an address struct.
129 * @param peer the peer
130 * @param transport_name plugin name
131 * @param address binary address
132 * @param address_length number of bytes in @a address
133 * @param local_info additional local information for the address
134 * @return the address struct
136 struct GNUNET_HELLO_Address *
137 GNUNET_HELLO_address_allocate (const struct GNUNET_PeerIdentity *peer,
138 const char *transport_name,
140 size_t address_length,
141 enum GNUNET_HELLO_AddressInfo local_info);
145 * Copy an address struct.
147 * @param address address to copy
148 * @return a copy of the address struct
150 struct GNUNET_HELLO_Address *
151 GNUNET_HELLO_address_copy (const struct GNUNET_HELLO_Address *address);
155 * Compare two addresses. Does NOT compare the peer identity,
156 * that is assumed already to match!
158 * @param a1 first address
159 * @param a2 second address
160 * @return 0 if the addresses are equal, -1 if @a a1< @a a2, 1 if @a a1> @a a2.
163 GNUNET_HELLO_address_cmp (const struct GNUNET_HELLO_Address *a1,
164 const struct GNUNET_HELLO_Address *a2);
168 * Get the size of an address struct.
170 * @param address address
174 GNUNET_HELLO_address_get_size (const struct GNUNET_HELLO_Address *address);
178 * Check if an address has a local option set
180 * @param address the address to check
181 * @param option the respective option to check for
182 * @return #GNUNET_YES or #GNUNET_NO
185 GNUNET_HELLO_address_check_option (const struct GNUNET_HELLO_Address *address,
186 enum GNUNET_HELLO_AddressInfo option);
192 * @param addr address to free
194 #define GNUNET_HELLO_address_free(addr) GNUNET_free (addr)
197 GNUNET_NETWORK_STRUCT_BEGIN
200 * A HELLO message is used to exchange information about
201 * transports with other peers. This struct is always
202 * followed by the actual network addresses which have
205 * 1) transport-name (0-terminated)
206 * 2) address-length (uint16_t, network byte order; possibly
208 * 3) address expiration (`struct GNUNET_TIME_AbsoluteNBO`); possibly
210 * 4) address (address-length bytes; possibly unaligned!)
212 struct GNUNET_HELLO_Message
215 * Type will be #GNUNET_MESSAGE_TYPE_HELLO.
217 struct GNUNET_MessageHeader header;
220 * Use in F2F mode: Do not gossip this HELLO message
222 uint32_t friend_only GNUNET_PACKED;
225 * The public key of the peer.
227 struct GNUNET_CRYPTO_EddsaPublicKey publicKey;
229 GNUNET_NETWORK_STRUCT_END
235 * @param h HELLO Message to test
236 * @return #GNUNET_YES for friend-only or #GNUNET_NO otherwise
239 GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h);
243 * Copy the given address information into
244 * the given buffer using the format of HELLOs.
246 * @param address address to add
247 * @param expiration expiration for the address
248 * @param target where to copy the address
249 * @param max maximum number of bytes to copy to @a target
250 * @return number of bytes copied, 0 if
251 * the target buffer was not big enough.
254 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
255 struct GNUNET_TIME_Absolute expiration,
261 * Callback function used to fill a buffer of max bytes with a list of
262 * addresses in the format used by HELLOs. Should use
263 * #GNUNET_HELLO_add_address() as a helper function.
266 * @param max maximum number of bytes that can be written to @a buf
267 * @param buf where to write the address information
268 * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
269 * end of the iteration.
271 typedef ssize_t (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
277 * Construct a HELLO message given the public key,
278 * expiration time and an iterator that spews the
279 * transport addresses.
281 * If friend only is set to #GNUNET_YES we create a FRIEND_HELLO which
282 * will not be gossiped to other peers.
284 * @param public_key public key to include in the HELLO
285 * @param addrgen callback to invoke to get addresses
286 * @param addrgen_cls closure for @a addrgen
287 * @param friend_only should the returned HELLO be only visible to friends?
288 * @return the hello message
290 struct GNUNET_HELLO_Message *
291 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
292 GNUNET_HELLO_GenerateAddressListCallback addrgen,
298 * Return the size of the given HELLO message.
300 * @param hello to inspect
301 * @return the size, 0 if HELLO is invalid
304 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
308 * Construct a HELLO message by merging the
309 * addresses in two existing HELLOs (which
310 * must be for the same peer).
312 * @param h1 first HELLO message
313 * @param h2 the second HELLO message
314 * @return the combined hello message
316 struct GNUNET_HELLO_Message *
317 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
318 const struct GNUNET_HELLO_Message *h2);
322 * Test if two HELLO messages contain the same addresses.
323 * If they only differ in expiration time, the lowest
324 * expiration time larger than 'now' where they differ
327 * @param h1 first HELLO message
328 * @param h2 the second HELLO message
329 * @param now time to use for deciding which addresses have
330 * expired and should not be considered at all
331 * @return absolute time forever if the two HELLOs are
332 * totally identical; smallest timestamp >= now if
333 * they only differ in timestamps;
334 * zero if the some addresses with expirations >= now
335 * do not match at all
337 struct GNUNET_TIME_Absolute
338 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
339 const struct GNUNET_HELLO_Message *h2,
340 struct GNUNET_TIME_Absolute now);
344 * Iterator callback to go over all addresses.
347 * @param address the address
348 * @param expiration expiration time
349 * @return #GNUNET_OK to keep the address,
350 * #GNUNET_NO to delete it from the HELLO
351 * #GNUNET_SYSERR to stop iterating (but keep current address)
353 typedef int (*GNUNET_HELLO_AddressIterator) (
355 const struct GNUNET_HELLO_Address *address,
356 struct GNUNET_TIME_Absolute expiration);
360 * When does the last address in the given HELLO expire?
362 * @param msg HELLO to inspect
363 * @return time the last address expires, 0 if there are no addresses in the HELLO
365 struct GNUNET_TIME_Absolute
366 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
370 * Iterate over all of the addresses in the HELLO.
372 * @param msg HELLO to iterate over; client does not need to
373 * have verified that msg is well-formed (beyond starting
374 * with a GNUNET_MessageHeader of the right type).
375 * @param return_modified if a modified copy should be returned,
376 * otherwise NULL will be returned
377 * @param it iterator to call on each address
378 * @param it_cls closure for @a it
379 * @return the modified HELLO or NULL
381 struct GNUNET_HELLO_Message *
382 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
384 GNUNET_HELLO_AddressIterator it,
389 * Iterate over addresses in @a new_hello that are NOT already present
390 * in @a old_hello. Note that if the address is present in @a old_hello
391 * but the expiration time in @a new_hello is more recent, the
392 * iterator is also called.
394 * @param new_hello a HELLO message
395 * @param old_hello a HELLO message
396 * @param expiration_limit ignore addresses in old_hello
397 * that expired before the given time stamp
398 * @param it iterator to call on each address
399 * @param it_cls closure for @a it
402 GNUNET_HELLO_iterate_new_addresses (
403 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);
474 #include "gnunet_nt_lib.h"
478 * Build address record by signing raw information with private key.
480 * @param address text address to sign
481 * @param nt network type of @a address
482 * @param mono_time when was @a address valid
483 * @param private_key signing key to use
484 * @param result[out] where to write address record (allocated)
485 * @param result_size[out] set to size of @a result
488 GNUNET_HELLO_sign_address (
490 enum GNUNET_NetworkType nt,
491 struct GNUNET_TIME_Absolute mono_time,
492 const struct GNUNET_CRYPTO_EddsaPrivateKey *private_key,
494 size_t *result_size);
498 * Check signature and extract address record.
500 * @param raw raw signed address
501 * @param raw_size size of @a raw
502 * @param pid public key to use for signature verification
503 * @param nt[out] set to network type
504 * @param mono_time[out] when was the address generated
505 * @return NULL on error, otherwise the address
508 GNUNET_HELLO_extract_address (const void *raw,
510 const struct GNUNET_PeerIdentity *pid,
511 enum GNUNET_NetworkType *nt,
512 struct GNUNET_TIME_Absolute *mono_time);
516 * Given an address as a string, extract the prefix that identifies
517 * the communicator offering transmissions to that address.
519 * @param address a peer's address
520 * @return NULL if the address is mal-formed, otherwise the prefix
523 GNUNET_HELLO_address_to_prefix (const char *address);
526 #if 0 /* keep Emacsens' auto-indent happy */
533 /* ifndef GNUNET_HELLO_LIB_H */
536 /** @} */ /* end of group */
538 /* end of gnunet_hello_lib.h */