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22 * @file include/gnunet_hello_lib.h
23 * @brief helper library for handling HELLOs
24 * @author Christian Grothoff
27 #ifndef GNUNET_HELLO_LIB_H
28 #define GNUNET_HELLO_LIB_H
33 #if 0 /* keep Emacsens' auto-indent happy */
38 #include "gnunet_common.h"
39 #include "gnunet_crypto_lib.h"
43 * Prefix that every HELLO URI must start with.
45 #define GNUNET_HELLO_URI_PREFIX "gnunet://hello/"
49 * An address for communicating with a peer. We frequently
50 * need this tuple and the components cannot really be
51 * separated. This is NOT the format that would be used
54 struct GNUNET_HELLO_Address
58 * For which peer is this an address?
60 struct GNUNET_PeerIdentity peer;
63 * Name of the transport plugin enabling the communication using
66 const char *transport_name;
69 * Binary representation of the address (plugin-specific).
74 * Number of bytes in 'address'.
76 size_t address_length;
82 * Allocate an address struct.
84 * @param peer the peer
85 * @param transport_name plugin name
86 * @param address binary address
87 * @param address_length number of bytes in 'address'
88 * @return the address struct
90 struct GNUNET_HELLO_Address *
91 GNUNET_HELLO_address_allocate (const struct GNUNET_PeerIdentity *peer,
92 const char *transport_name, const void *address,
93 size_t address_length);
97 * Copy an address struct.
99 * @param address address to copy
100 * @return a copy of the address struct
102 struct GNUNET_HELLO_Address *
103 GNUNET_HELLO_address_copy (const struct GNUNET_HELLO_Address *address);
107 * Compare two addresses. Does NOT compare the peer identity,
108 * that is assumed already to match!
110 * @param a1 first address
111 * @param a2 second address
112 * @return 0 if the addresses are equal, -1 if a1<a2, 1 if a1>a2.
115 GNUNET_HELLO_address_cmp (const struct GNUNET_HELLO_Address *a1,
116 const struct GNUNET_HELLO_Address *a2);
120 * Get the size of an address struct.
122 * @param address address
126 GNUNET_HELLO_address_get_size (const struct GNUNET_HELLO_Address *address);
131 * @param addr address to free
133 #define GNUNET_HELLO_address_free(addr) GNUNET_free(addr)
137 * A HELLO message is used to exchange information about
138 * transports with other peers. This struct is guaranteed
139 * to start with a "GNUNET_MessageHeader", everything else
140 * should be internal to the HELLO library.
142 struct GNUNET_HELLO_Message;
146 * Copy the given address information into
147 * the given buffer using the format of HELLOs.
149 * @param address address to add
150 * @param expiration expiration for the address
151 * @param target where to copy the address
152 * @param max maximum number of bytes to copy to target
153 * @return number of bytes copied, 0 if
154 * the target buffer was not big enough.
157 GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
158 struct GNUNET_TIME_Absolute expiration, char *target,
163 * Callback function used to fill a buffer of max bytes with a list of
164 * addresses in the format used by HELLOs. Should use
165 * "GNUNET_HELLO_add_address" as a helper function.
168 * @param max maximum number of bytes that can be written to buf
169 * @param buf where to write the address information
170 * @return number of bytes written, 0 to signal the
171 * end of the iteration.
173 typedef size_t (*GNUNET_HELLO_GenerateAddressListCallback) (void *cls,
179 * Construct a HELLO message given the public key,
180 * expiration time and an iterator that spews the
181 * transport addresses.
183 * @return the hello message
185 struct GNUNET_HELLO_Message *
186 GNUNET_HELLO_create (const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
188 GNUNET_HELLO_GenerateAddressListCallback addrgen,
193 * Return the size of the given HELLO message.
194 * @param hello to inspect
195 * @return the size, 0 if HELLO is invalid
198 GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello);
202 * Construct a HELLO message by merging the
203 * addresses in two existing HELLOs (which
204 * must be for the same peer).
206 * @param h1 first HELLO message
207 * @param h2 the second HELLO message
208 * @return the combined hello message
210 struct GNUNET_HELLO_Message *
211 GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
212 const struct GNUNET_HELLO_Message *h2);
216 * Test if two HELLO messages contain the same addresses.
217 * If they only differ in expiration time, the lowest
218 * expiration time larger than 'now' where they differ
221 * @param h1 first HELLO message
222 * @param h2 the second HELLO message
223 * @param now time to use for deciding which addresses have
224 * expired and should not be considered at all
225 * @return absolute time forever if the two HELLOs are
226 * totally identical; smallest timestamp >= now if
227 * they only differ in timestamps;
228 * zero if the some addresses with expirations >= now
229 * do not match at all
231 struct GNUNET_TIME_Absolute
232 GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
233 const struct GNUNET_HELLO_Message *h2,
234 struct GNUNET_TIME_Absolute now);
238 * Iterator callback to go over all addresses.
241 * @param address the address
242 * @param expiration expiration time
243 * @return GNUNET_OK to keep the address,
244 * GNUNET_NO to delete it from the HELLO
245 * GNUNET_SYSERR to stop iterating (but keep current address)
247 typedef int (*GNUNET_HELLO_AddressIterator) (void *cls,
248 const struct GNUNET_HELLO_Address *
250 struct GNUNET_TIME_Absolute
255 * When does the last address in the given HELLO expire?
257 * @param msg HELLO to inspect
258 * @return time the last address expires, 0 if there are no addresses in the HELLO
260 struct GNUNET_TIME_Absolute
261 GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg);
265 * Iterate over all of the addresses in the HELLO.
267 * @param msg HELLO to iterate over; client does not need to
268 * have verified that msg is well-formed (beyond starting
269 * with a GNUNET_MessageHeader of the right type).
270 * @param return_modified if a modified copy should be returned,
271 * otherwise NULL will be returned
272 * @param it iterator to call on each address
273 * @param it_cls closure for it
274 * @return the modified HELLO or NULL
276 struct GNUNET_HELLO_Message *
277 GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
279 GNUNET_HELLO_AddressIterator it, void *it_cls);
283 * Iterate over addresses in "new_hello" that
284 * are NOT already present in "old_hello".
286 * @param new_hello a HELLO message
287 * @param old_hello a HELLO message
288 * @param expiration_limit ignore addresses in old_hello
289 * that expired before the given time stamp
290 * @param it iterator to call on each address
291 * @param it_cls closure for it
294 GNUNET_HELLO_iterate_new_addresses (const struct GNUNET_HELLO_Message
296 const struct GNUNET_HELLO_Message
298 struct GNUNET_TIME_Absolute
300 GNUNET_HELLO_AddressIterator it,
305 * Get the public key from a HELLO message.
307 * @param hello the hello message
308 * @param publicKey where to copy the public key information, can be NULL
309 * @return GNUNET_SYSERR if the HELLO was malformed
312 GNUNET_HELLO_get_key (const struct GNUNET_HELLO_Message *hello,
313 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
318 * Get the peer identity from a HELLO message.
320 * @param hello the hello message
321 * @param peer where to store the peer's identity
322 * @return GNUNET_SYSERR if the HELLO was malformed
325 GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
326 struct GNUNET_PeerIdentity *peer);
330 * Get the header from a HELLO message, used so other code
331 * can correctly send HELLO messages.
333 * @param hello the hello message
335 * @return header or NULL if the HELLO was malformed
337 struct GNUNET_MessageHeader *
338 GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello);
341 typedef struct GNUNET_TRANSPORT_PluginFunctions *
342 (*GNUNET_HELLO_TransportPluginsFind) (const char *name);
346 * Compose a hello URI string from a hello message.
348 * @param hello Hello message
349 * @param plugins_find Function to find transport plugins by name
350 * @return Hello URI string
353 GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
354 GNUNET_HELLO_TransportPluginsFind plugins_find);
357 * Parse a hello URI string to a hello message.
359 * @param uri URI string to parse
360 * @param pubkey Pointer to struct where public key is parsed
361 * @param hello Pointer to struct where hello message is parsed
362 * @param plugins_find Function to find transport plugins by name
363 * @return GNUNET_OK on success, GNUNET_SYSERR if the URI was invalid, GNUNET_NO on other errors
366 GNUNET_HELLO_parse_uri (const char *uri,
367 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *pubkey,
368 struct GNUNET_HELLO_Message **hello,
369 GNUNET_HELLO_TransportPluginsFind plugins_find);
371 #if 0 /* keep Emacsens' auto-indent happy */
379 /* ifndef GNUNET_HELLO_LIB_H */
381 /* end of gnunet_hello_lib.h */