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20 * @author Christian Grothoff
22 * Helper library for handling HELLOs
24 * @defgroup hello Hello library
25 * Helper library for handling HELLOs
27 * @see [Documentation](https://gnunet.org/gnunets-hostlist-subsystem)
32 #ifndef GNUNET_HELLO_LIB_H
33 #define GNUNET_HELLO_LIB_H
38 #if 0 /* keep Emacsens' auto-indent happy */
43 #include "gnunet_util_lib.h"
46 * Prefix that every HELLO URI must start with.
48 #define GNUNET_HELLO_URI_PREFIX "gnunet://hello/"
51 * Prefix that every FRIEND HELLO URI must start with.
53 #define GNUNET_FRIEND_HELLO_URI_PREFIX "gnunet://friend-hello/"
56 * Separator used in HELLO URI
58 #define GNUNET_HELLO_URI_SEP '+'
62 * Additional local information about an address
64 * These information are only valid for the local peer and are not serialized
65 * when a #GNUNET_HELLO_Message is created
67 enum GNUNET_HELLO_AddressInfo
70 * No additional information
72 GNUNET_HELLO_ADDRESS_INFO_NONE = 0,
75 * This is an inbound address and cannot be used to initiate an outbound
76 * connection to another peer
78 GNUNET_HELLO_ADDRESS_INFO_INBOUND = 1
83 * An address for communicating with a peer. We frequently
84 * need this tuple and the components cannot really be
85 * separated. This is NOT the format that would be used
88 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;
128 * Allocate an address struct.
130 * @param peer the peer
131 * @param transport_name plugin name
132 * @param address binary address
133 * @param address_length number of bytes in @a address
134 * @param local_info additional local information for the address
135 * @return the address struct
137 struct GNUNET_HELLO_Address *
138 GNUNET_HELLO_address_allocate (const struct GNUNET_PeerIdentity *peer,
139 const char *transport_name,
141 size_t address_length,
142 enum GNUNET_HELLO_AddressInfo local_info);
146 * Copy an address struct.
148 * @param address address to copy
149 * @return a copy of the address struct
151 struct GNUNET_HELLO_Address *
152 GNUNET_HELLO_address_copy (const struct GNUNET_HELLO_Address *address);
156 * Compare two addresses. Does NOT compare the peer identity,
157 * that is assumed already to match!
159 * @param a1 first address
160 * @param a2 second address
161 * @return 0 if the addresses are equal, -1 if @a a1< @a a2, 1 if @a a1> @a a2.
164 GNUNET_HELLO_address_cmp (const struct GNUNET_HELLO_Address *a1,
165 const struct GNUNET_HELLO_Address *a2);
169 * Get the size of an address struct.
171 * @param address address
175 GNUNET_HELLO_address_get_size (const struct GNUNET_HELLO_Address *address);
179 * Check if an address has a local option set
181 * @param address the address to check
182 * @param option the respective option to check for
183 * @return #GNUNET_YES or #GNUNET_NO
186 GNUNET_HELLO_address_check_option (const struct GNUNET_HELLO_Address *address,
187 enum GNUNET_HELLO_AddressInfo option);
193 * @param addr address to free
195 #define GNUNET_HELLO_address_free(addr) GNUNET_free(addr)
198 GNUNET_NETWORK_STRUCT_BEGIN
201 * A HELLO message is used to exchange information about
202 * transports with other peers. This struct is always
203 * followed by the actual network addresses which have
206 * 1) transport-name (0-terminated)
207 * 2) address-length (uint16_t, network byte order; possibly
209 * 3) address expiration (`struct GNUNET_TIME_AbsoluteNBO`); possibly
211 * 4) address (address-length bytes; possibly unaligned!)
213 struct GNUNET_HELLO_Message
216 * Type will be #GNUNET_MESSAGE_TYPE_HELLO.
218 struct GNUNET_MessageHeader header;
221 * Use in F2F mode: Do not gossip this HELLO message
223 uint32_t friend_only GNUNET_PACKED;
226 * The public key of the peer.
228 struct GNUNET_CRYPTO_EddsaPublicKey publicKey;
231 GNUNET_NETWORK_STRUCT_END
238 * @param h HELLO Message to test
239 * @return #GNUNET_YES for friend-only or #GNUNET_NO otherwise
242 GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h);
246 * Copy the given address information into
247 * the given buffer using the format of HELLOs.
249 * @param address address to add
250 * @param expiration expiration for the address
251 * @param target where to copy the address
252 * @param max maximum number of bytes to copy to @a target
253 * @return number of bytes copied, 0 if
254 * the target buffer was not big enough.
257 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
258 struct GNUNET_TIME_Absolute expiration,
264 * Callback function used to fill a buffer of max bytes with a list of
265 * addresses in the format used by HELLOs. Should use
266 * #GNUNET_HELLO_add_address() as a helper function.
269 * @param max maximum number of bytes that can be written to @a buf
270 * @param buf where to write the address information
271 * @return number of bytes written or 0, #GNUNET_SYSERR to signal the
272 * end of the iteration.
275 (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
281 * Construct a HELLO message given the public key,
282 * expiration time and an iterator that spews the
283 * transport addresses.
285 * If friend only is set to #GNUNET_YES we create a FRIEND_HELLO which
286 * will not be gossiped to other peers.
288 * @param public_key public key to include in the HELLO
289 * @param addrgen callback to invoke to get addresses
290 * @param addrgen_cls closure for @a addrgen
291 * @param friend_only should the returned HELLO be only visible to friends?
292 * @return the hello message
294 struct GNUNET_HELLO_Message *
295 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
296 GNUNET_HELLO_GenerateAddressListCallback addrgen,
302 * Return the size of the given HELLO message.
304 * @param hello to inspect
305 * @return the size, 0 if HELLO is invalid
308 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
312 * Construct a HELLO message by merging the
313 * addresses in two existing HELLOs (which
314 * must be for the same peer).
316 * @param h1 first HELLO message
317 * @param h2 the second HELLO message
318 * @return the combined hello message
320 struct GNUNET_HELLO_Message *
321 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
322 const struct GNUNET_HELLO_Message *h2);
326 * Test if two HELLO messages contain the same addresses.
327 * If they only differ in expiration time, the lowest
328 * expiration time larger than 'now' where they differ
331 * @param h1 first HELLO message
332 * @param h2 the second HELLO message
333 * @param now time to use for deciding which addresses have
334 * expired and should not be considered at all
335 * @return absolute time forever if the two HELLOs are
336 * totally identical; smallest timestamp >= now if
337 * they only differ in timestamps;
338 * zero if the some addresses with expirations >= now
339 * do not match at all
341 struct GNUNET_TIME_Absolute
342 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
343 const struct GNUNET_HELLO_Message *h2,
344 struct GNUNET_TIME_Absolute now);
348 * Iterator callback to go over all addresses.
351 * @param address the address
352 * @param expiration expiration time
353 * @return #GNUNET_OK to keep the address,
354 * #GNUNET_NO to delete it from the HELLO
355 * #GNUNET_SYSERR to stop iterating (but keep current address)
358 (*GNUNET_HELLO_AddressIterator) (void *cls,
359 const struct GNUNET_HELLO_Address *address,
360 struct GNUNET_TIME_Absolute expiration);
364 * When does the last address in the given HELLO expire?
366 * @param msg HELLO to inspect
367 * @return time the last address expires, 0 if there are no addresses in the HELLO
369 struct GNUNET_TIME_Absolute
370 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
374 * Iterate over all of the addresses in the HELLO.
376 * @param msg HELLO to iterate over; client does not need to
377 * have verified that msg is well-formed (beyond starting
378 * with a GNUNET_MessageHeader of the right type).
379 * @param return_modified if a modified copy should be returned,
380 * otherwise NULL will be returned
381 * @param it iterator to call on each address
382 * @param it_cls closure for @a it
383 * @return the modified HELLO or NULL
385 struct GNUNET_HELLO_Message *
386 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
388 GNUNET_HELLO_AddressIterator it, void *it_cls);
392 * Iterate over addresses in @a new_hello that are NOT already present
393 * in @a old_hello. Note that if the address is present in @a old_hello
394 * but the expiration time in @a new_hello is more recent, the
395 * iterator is also called.
397 * @param new_hello a HELLO message
398 * @param old_hello a HELLO message
399 * @param expiration_limit ignore addresses in old_hello
400 * that expired before the given time stamp
401 * @param it iterator to call on each address
402 * @param it_cls closure for @a it
405 GNUNET_HELLO_iterate_new_addresses (const struct GNUNET_HELLO_Message *new_hello,
406 const struct GNUNET_HELLO_Message *old_hello,
407 struct GNUNET_TIME_Absolute expiration_limit,
408 GNUNET_HELLO_AddressIterator it,
413 * Get the peer identity from a HELLO message.
415 * @param hello the hello message
416 * @param peer where to store the peer's identity
417 * @return #GNUNET_SYSERR if the HELLO was malformed
420 GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
421 struct GNUNET_PeerIdentity *peer);
425 * Get the header from a HELLO message, used so other code
426 * can correctly send HELLO messages.
428 * @param hello the hello message
430 * @return header or NULL if the HELLO was malformed
432 struct GNUNET_MessageHeader *
433 GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello);
437 * Helper function to load/access transport plugins.
438 * FIXME: pass closure!
440 * @param name name of the transport plugin to load
441 * @return NULL if a plugin with name @a name is not known/loadable
443 typedef struct GNUNET_TRANSPORT_PluginFunctions *
444 (*GNUNET_HELLO_TransportPluginsFind) (const char *name);
448 * Compose a hello URI string from a hello message.
450 * @param hello Hello message
451 * @param plugins_find Function to find transport plugins by name
452 * @return Hello URI string
455 GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
456 GNUNET_HELLO_TransportPluginsFind plugins_find);
460 * Parse a hello URI string to a hello message.
462 * @param uri URI string to parse
463 * @param pubkey Pointer to struct where public key is parsed
464 * @param hello Pointer to struct where hello message is parsed
465 * @param plugins_find Function to find transport plugins by name
466 * @return #GNUNET_OK on success, #GNUNET_SYSERR if the URI was invalid, #GNUNET_NO on other errors
469 GNUNET_HELLO_parse_uri (const char *uri,
470 struct GNUNET_CRYPTO_EddsaPublicKey *pubkey,
471 struct GNUNET_HELLO_Message **hello,
472 GNUNET_HELLO_TransportPluginsFind plugins_find);
477 #include "gnunet_nt_lib.h"
480 * Key used for storing HELLOs in the peerstore
482 #define GNUNET_HELLO_PEERSTORE_KEY "hello"
485 * Build address record by signing raw information with private key.
487 * @param address text address to sign
488 * @param nt network type of @a address
489 * @param expiration how long is @a address valid
490 * @param private_key signing key to use
491 * @param result[out] where to write address record (allocated)
492 * @param result_size[out] set to size of @a result
495 GNUNET_HELLO_sign_address (const char *address,
496 enum GNUNET_NetworkType nt,
497 struct GNUNET_TIME_Absolute expiration,
498 const struct GNUNET_CRYPTO_EddsaPrivateKey *private_key,
500 size_t *result_size);
504 * Check signature and extract address record.
506 * @param raw raw signed address
507 * @param raw_size size of @a raw
508 * @param pid public key to use for signature verification
509 * @param nt[out] set to network type
510 * @param expiration[out] how long is the address valid
511 * @return NULL on error, otherwise the address
514 GNUNET_HELLO_extract_address (const void *raw,
516 const struct GNUNET_PeerIdentity *pid,
517 enum GNUNET_NetworkType *nt,
518 struct GNUNET_TIME_Absolute *expiration);
522 #if 0 /* keep Emacsens' auto-indent happy */
529 /* ifndef GNUNET_HELLO_LIB_H */
532 /** @} */ /* end of group */
534 /* end of gnunet_hello_lib.h */