5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 2000 - 2001 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
24 #include "clientlibincludes.h"
27 This file defines the SILC Client Library API for the application. The
28 client operations are defined first. These are callback functions that
29 the application MUST implement since the library may call the functions
30 at any time. At the end of file is the API for the application that
31 it can use from the library. This is the only file that the application
32 may include from the SIlC Client Library.
34 Please, refer to the README file in this directory for the directions
35 of how to use the SILC Client Library.
38 /******************************************************************************
40 SILC Client Operations
42 These functions must be implemented by the application calling the SILC
43 client library. The client library can call these functions at any time.
45 To use this structure: define a static SilcClientOperations variable,
46 fill it and pass its pointer to silc_client_alloc function.
48 ******************************************************************************/
50 /* SILC Client Operations. These must be implemented by the application. */
52 /* Message sent to the application by library. `conn' associates the
53 message to a specific connection. `conn', however, may be NULL. */
54 void (*say)(SilcClient client, SilcClientConnection conn, char *msg, ...);
56 /* Message for a channel. The `sender' is the sender of the message
57 The `channel' is the channel. */
58 void (*channel_message)(SilcClient client, SilcClientConnection conn,
59 SilcClientEntry sender, SilcChannelEntry channel,
62 /* Private message to the client. The `sender' is the sender of the
64 void (*private_message)(SilcClient client, SilcClientConnection conn,
65 SilcClientEntry sender, char *msg);
68 /* Notify message to the client. The notify arguments are sent in the
69 same order as servers sends them. The arguments are same as received
70 from the server except for ID's. If ID is received application receives
71 the corresponding entry to the ID. For example, if Client ID is received
72 application receives SilcClientEntry. Also, if the notify type is
73 for channel the channel entry is sent to application (even if server
74 does not send it because client library gets the channel entry from
75 the Channel ID in the packet's header). */
76 void (*notify)(SilcClient client, SilcClientConnection conn,
77 SilcNotifyType type, ...);
80 /* Command handler. This function is called always in the command function.
81 If error occurs it will be called as well. `conn' is the associated
82 client connection. `cmd_context' is the command context that was
83 originally sent to the command. `success' is FALSE if error occured
84 during command. `command' is the command being processed. It must be
85 noted that this is not reply from server. This is merely called just
86 after application has called the command. Just to tell application
87 that the command really was processed. */
88 void (*command)(SilcClient client, SilcClientConnection conn,
89 SilcClientCommandContext cmd_context, int success,
93 /* Command reply handler. This function is called always in the command reply
94 function. If error occurs it will be called as well. Normal scenario
95 is that it will be called after the received command data has been parsed
96 and processed. The function is used to pass the received command data to
99 `conn' is the associated client connection. `cmd_payload' is the command
100 payload data received from server and it can be ignored. It is provided
101 if the application would like to re-parse the received command data,
102 however, it must be noted that the data is parsed already by the library
103 thus the payload can be ignored. `success' is FALSE if error occured.
104 In this case arguments are not sent to the application. The `status' is
105 the command reply status server returned. The `command' is the command
106 reply being processed. The function has variable argument list and each
107 command defines the number and type of arguments it passes to the
108 application (on error they are not sent). */
109 void (*command_reply)(SilcClient client, SilcClientConnection conn,
110 SilcCommandPayload cmd_payload, int success,
111 SilcCommand command, SilcCommandStatus status, ...);
113 /* Called to indicate that connection was either successfully established
114 or connecting failed. This is also the first time application receives
115 the SilcClientConnection objecet which it should save somewhere. */
116 void (*connect)(SilcClient client, SilcClientConnection conn, int success);
118 /* Called to indicate that connection was disconnected to the server. */
119 void (*disconnect)(SilcClient client, SilcClientConnection conn);
121 /* Find authentication method and authentication data by hostname and
122 port. The hostname may be IP address as well. The found authentication
123 method and authentication data is returned to `auth_meth', `auth_data'
124 and `auth_data_len'. The function returns TRUE if authentication method
125 is found and FALSE if not. `conn' may be NULL. */
126 int (*get_auth_method)(SilcClient client, SilcClientConnection conn,
127 char *hostname, unsigned short port,
128 SilcProtocolAuthMeth *auth_meth,
129 unsigned char **auth_data,
130 unsigned int *auth_data_len);
132 /* Verifies received public key. The public key has been received from
133 a server. If user decides to trust the key may be saved as trusted
134 server key for later use. If user does not trust the key this returns
135 FALSE. If everything is Ok this returns TRUE. */
136 int (*verify_server_key)(SilcClient client, SilcClientConnection conn,
137 unsigned char *pk, unsigned int pk_len,
138 SilcSKEPKType pk_type);
140 /* Ask (interact, that is) a passphrase from user. Returns the passphrase
142 unsigned char *(*ask_passphrase)(SilcClient client,
143 SilcClientConnection conn);
145 /* Notifies application that failure packet was received. This is called
146 if there is some protocol active in the client. The `protocol' is the
147 protocol context. The `failure' is opaque pointer to the failure
148 indication. Note, that the `failure' is protocol dependant and
149 application must explicitly cast it to correct type. Usually `failure'
150 is 32 bit failure type (see protocol specs for all protocol failure
152 void (*failure)(SilcClient client, SilcClientConnection conn,
153 SilcProtocol protocol, void *failure);
155 /* Asks whether the user would like to perform the key agreement protocol.
156 This is called after we have received an key agreement packet or an
157 reply to our key agreement packet. This returns TRUE if the user wants
158 the library to perform the key agreement protocol and FALSE if it is not
160 int (*key_agreement)(SilcClient client, SilcClientConnection conn,
161 SilcClientEntry client_entry);
162 } SilcClientOperations;
166 /******************************************************************************
168 SILC Client Library API
170 This is the API that is published by the SILC Client Library for the
171 applications. These functions are implemented in the SILC Client Library.
172 Application may freely call these functions from the library.
174 ******************************************************************************/
176 /* Initialization functions */
178 /* Allocates new client object. This has to be done before client may
179 work. After calling this one must call silc_client_init to initialize
180 the client. The `application' is application specific user data pointer
181 and caller must free it. */
182 SilcClient silc_client_alloc(SilcClientOperations *ops, void *application);
184 /* Frees client object and its internals. */
185 void silc_client_free(SilcClient client);
187 /* Initializes the client. This makes all the necessary steps to make
188 the client ready to be run. One must call silc_client_run to run the
189 client. Returns FALSE if error occured, TRUE otherwise. */
190 int silc_client_init(SilcClient client);
192 /* Runs the client. This starts the scheduler from the utility library.
193 When this functions returns the execution of the appliation is over. */
194 void silc_client_run(SilcClient client);
196 /* Stops the client. This is called to stop the client and thus to stop
198 void silc_client_stop(SilcClient client);
201 /* Connecting functions */
203 /* Connects to remote server. This is the main routine used to connect
204 to SILC server. Returns -1 on error and the created socket otherwise.
205 The `context' is user context that is saved into the SilcClientConnection
206 that is created after the connection is created. Note that application
207 may handle the connecting process outside the library. If this is the
208 case then this function is not used at all. When the connecting is
209 done the `connect' client operation is called. */
210 int silc_client_connect_to_server(SilcClient client, int port,
211 char *host, void *context);
213 /* Allocates and adds new connection to the client. This adds the allocated
214 connection to the connection table and returns a pointer to it. A client
215 can have multiple connections to multiple servers. Every connection must
216 be added to the client using this function. User data `context' may
217 be sent as argument. This function is normally used only if the
218 application performed the connecting outside the library. The library
219 however may use this internally. */
220 SilcClientConnection silc_client_add_connection(SilcClient client,
225 /* Removes connection from client. Frees all memory. */
226 void silc_client_del_connection(SilcClient client, SilcClientConnection conn);
228 /* Start SILC Key Exchange (SKE) protocol to negotiate shared secret
229 key material between client and server. This function can be called
230 directly if application is performing its own connecting and does not
231 use the connecting provided by this library. This function is normally
232 used only if the application performed the connecting outside the library.
233 The library however may use this internally. */
234 int silc_client_start_key_exchange(SilcClient client,
235 SilcClientConnection conn,
238 /* Closes connection to remote end. Free's all allocated data except
239 for some information such as nickname etc. that are valid at all time. */
240 void silc_client_close_connection(SilcClient client,
241 SilcClientConnection conn);
244 /* Message sending functions */
246 /* Sends packet to the `channel'. Packet to channel is always encrypted
247 differently from "normal" packets. SILC header of the packet is
248 encrypted with the next receiver's key and the rest of the packet is
249 encrypted with the channel specific key. Padding and HMAC is computed
250 with the next receiver's key. The `data' is the channel message. If
251 the `force_send' is TRUE then the packet is sent immediately. */
252 void silc_client_send_channel_message(SilcClient client,
253 SilcClientConnection conn,
254 SilcChannelEntry channel,
256 unsigned int data_len,
259 /* Sends private message to remote client. If private message key has
260 not been set with this client then the message will be encrypted using
261 normal session keys. Private messages are special packets in SILC
262 network hence we need this own function for them. This is similiar
263 to silc_client_packet_send_to_channel except that we send private
264 message. The `data' is the private message. If the `force_send' is
265 TRUE the packet is sent immediately. */
266 void silc_client_send_private_message(SilcClient client,
267 SilcClientConnection conn,
268 SilcClientEntry client_entry,
270 unsigned int data_len,
274 /* Client and Channel entry retrieval */
276 /* Callback function given to the silc_client_get_client function. The
277 found entries are allocated into the `clients' array. The array must
278 not be freed by the caller, the library will free it later. If the
279 `clients' is NULL, no such clients exist in the SILC Network. */
280 typedef void (*SilcGetClientCallback)(SilcClient client,
281 SilcClientConnection conn,
282 SilcClientEntry *clients,
283 unsigned int clients_count,
286 /* Finds client entry or entries by the `nickname' and `server'. The
287 completion callback will be called when the client entries has been found.
289 Note: this function is always asynchronous and resolves the client
290 information from the server. Thus, if you already know the client
291 information then use the silc_client_get_client_by_id function to
292 get the client entry since this function may be very slow and should
293 be used only to initially get the client entries. */
294 void silc_client_get_clients(SilcClient client,
295 SilcClientConnection conn,
298 SilcGetClientCallback completion,
301 /* Same as above function but does not resolve anything from the server.
302 This checks local cache and returns all clients from the cache. */
303 SilcClientEntry *silc_client_get_clients_local(SilcClient client,
304 SilcClientConnection conn,
307 unsigned int *clients_count);
309 /* Find entry for client by the client's ID. Returns the entry or NULL
310 if the entry was not found. */
311 SilcClientEntry silc_client_get_client_by_id(SilcClient client,
312 SilcClientConnection conn,
313 SilcClientID *client_id);
315 /* Finds entry for channel by the channel name. Returns the entry or NULL
316 if the entry was not found. It is found only if the client is joined
318 SilcChannelEntry silc_client_get_channel(SilcClient client,
319 SilcClientConnection conn,
323 /* Command management */
325 /* Allocate Command Context. The context is defined in `command.h' file.
326 The context is used by the library commands and applications should use
327 it as well. However, application may choose to use some own context
328 for its local commands. All library commands, however, must use this
330 SilcClientCommandContext silc_client_command_alloc();
332 /* Free command context and its internals */
333 void silc_client_command_free(SilcClientCommandContext ctx);
335 /* Duplicate Command Context by adding reference counter. The context won't
336 be free'd untill it hits zero. */
337 SilcClientCommandContext silc_client_command_dup(SilcClientCommandContext ctx);
339 /* Finds and returns a pointer to the command list. Return NULL if the
340 command is not found. See the `command.[ch]' for the command list. */
341 SilcClientCommand *silc_client_command_find(const char *name);
343 /* Generic function to send any command. The arguments must be sent already
344 encoded into correct form and in correct order. */
345 void silc_client_send_command(SilcClient client, SilcClientConnection conn,
346 SilcCommand command, unsigned short ident,
347 unsigned int argc, ...);
349 /* Pending Command callback destructor. This is called after calling the
350 pending callback or if error occurs while processing the pending command.
351 If error occurs then the callback won't be called at all, and only this
352 destructor is called. The `context' is the context given for the function
353 silc_client_command_pending. */
354 typedef void (*SilcClientPendingDestructor)(void *context);
356 /* Add new pending command to be executed when reply to a command has been
357 received. The `reply_cmd' is the command that will call the `callback'
358 with `context' when reply has been received. If `ident is non-zero
359 the `callback' will be executed when received reply with command
360 identifier `ident'. */
361 void silc_client_command_pending(SilcClientConnection conn,
362 SilcCommand reply_cmd,
363 unsigned short ident,
364 SilcClientPendingDestructor destructor,
365 SilcCommandCb callback,
369 /* Private Message key management */
371 /* Adds private message key to the client library. The key will be used to
372 encrypt all private message between the client and the remote client
373 indicated by the `client_entry'. If the key and the IV arguments are NULL
374 and the boolean value `generate_key' is TRUE the library will generate
375 random key. Otherwise, the key material provided by the application
376 will be used. It maybe random key or pre-shared-key. If the send
377 and receive keys should be same they may be set to same. Same applies
378 for send IV and receive IV, they maybe same. If the IV arguments
379 are NULL, the library will use NULL as IV (may not be desired from
380 the security persperctive).
382 It is not necessary to set key for normal private message usage. If the
383 key is not set then the private messages are encrypted using normal
384 session keys. Setting the private key, however, increases the security.
386 Note that the key set using this function is sent to the remote client
387 through the SILC network. The packet is protected using normal session
390 Returns FALSE if the key is already set for the `client_entry', TRUE
392 int silc_client_add_private_message_key(SilcClient client,
393 SilcClientConnection conn,
394 SilcClientConnection client_entry,
395 unsigned char *send_key,
396 unsigned int send_key_len,
397 unsigned char *receive_key,
398 unsigned int receive_key_len,
399 unsigned char *send_iv,
400 unsigned int send_iv_len,
401 unsigned char *receive_iv;
402 unsigned int receive_iv_len,
405 /* Removes the private message from the library. The key won't be used
406 after this to protect the private messages with the remote `client_entry'
407 client. Returns FALSE on error, TRUE otherwise. */
408 int silc_client_del_private_message_key(SilcClient client,
409 SilcClientConnection conn,
410 SilcClientEntry client_entry);
412 /* Structure to hold the list of private message keys. The array of this
413 structure is returned by the silc_client_list_private_message_keys
414 function. The IV's are not returned as they are not important. */
416 SilcClientEntry client_entry; /* The remote client entry */
417 unsigned char *send_key; /* The raw key data */
418 unsigned int send_key_len; /* The key length */
419 unsigned char *receive_key; /* The raw key data */
420 unsigned int receive_key_len; /* The key length */
421 int generated; /* TRUE if library generated the key */
422 } *SilcPrivateMessageKeys;
424 /* Returns array of set private message keys associated to the connection
425 `conn'. Returns allocated SilcPrivateMessageKeys array and the array
426 count to the `key_count' argument. The array must be freed by the caller
427 by calling the silc_client_free_private_message_keys function. Note:
428 the keys returned in the array is in raw format. It might not be desired
429 to show the keys as is. The application might choose not to show the keys
430 at all or to show the fingerprints of the keys. */
431 SilcPrivateMessageKeys
432 silc_client_list_private_message_keys(SilcClient client,
433 SilcClientConnection conn,
434 unsigned int *key_count);
436 /* Frees the SilcPrivateMessageKeys array returned by the function
437 silc_client_list_private_message_keys. */
438 void silc_client_free_private_message_keys(SilcPrivateMessageKeys keys,
439 unsigned int key_count);
442 /* Channel private key management */
444 /* Adds private key for channel. This may be set only if the channel's mode
445 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
446 mode is not set. When channel has private key then the messages are
447 encrypted using that key. All clients on the channel must also know the
448 key in order to decrypt the messages. However, it is possible to have
449 several private keys per one channel. In this case only some of the
450 clients on the channel may now the one key and only some the other key.
452 The private key for channel is optional. If it is not set then the
453 channel messages are encrypted using the channel key generated by the
454 server. However, setting the private key (or keys) for the channel
455 significantly adds security. If more than one key is set the library
456 will automatically try all keys at the message decryption phase. Note:
457 setting many keys slows down the decryption phase as all keys has to
458 be tried in order to find the correct decryption key. However, setting
459 a few keys does not have big impact to the decryption performace.
461 NOTE: that this is entirely local setting. The key set using this function
462 is not sent to the network at any phase.
464 NOTE: If the key material was originated by the SKE protocol (using
465 silc_client_send_key_agreement) then the `key' MUST be the
466 key->send_enc_key as this is dictated by the SILC protocol. However,
467 currently it is not expected that the SKE key material would be used
468 as channel private key. */
469 int silc_client_add_channel_private_key(SilcClient client,
470 SilcClientConnection conn,
471 SilcChannelEntry channel,
473 unsigned int key_len);
475 /* Removes all private keys from the `channel'. The old channel key is used
476 after calling this to protect the channel messages. Returns FALSE on
477 on error, TRUE otherwise. */
478 int silc_client_del_channel_private_keys(SilcClient client,
479 SilcClientConnection conn,
480 SilcChannelEntry channel);
482 /* Structure to hold one channel private key. */
484 unsigned char *key; /* The key */
485 unsigned int key_len; /* The key length */
486 } *SilcChannelPrivateKey;
488 /* Removes and frees private key `key' from the channel `channel'. The `key'
489 is retrieved by calling the function silc_client_list_channel_private_keys.
490 The key is not used after this. If the key was last private key then the
491 old channel key is used hereafter to protect the channel messages. This
492 returns FALSE on error, TRUE otherwise. */
493 int silc_client_del_channel_private_key(SilcClient client,
494 SilcClientConnection conn,
495 SilcChannelEntry channel,
496 SilcChannelPrivateKey key);
498 /* Returns array (pointers) of private keys associated to the `channel'.
499 The caller must free the array by calling the function
500 silc_client_free_channel_private_keys. The pointers in the array may be
501 used to delete the specific key by giving the pointer as argument to the
502 function silc_client_del_channel_private_key. */
503 SilcChannelPrivateKey *
504 silc_client_list_channel_private_keys(SilcClient client,
505 SilcClientConnection conn,
506 SilcChannelEntry channel,
507 unsigned int key_count);
509 /* Frees the SilcChannelPrivateKey array. */
510 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
511 unsigned int key_count);
514 /* Key Agreement routines */
516 /* Key agreement callback that is called after the key agreement protocol
517 has been performed. This is called also if error occured during the
518 key agreement protocol. The `key' is the allocated key material and
519 the caller is responsible of freeing it. The `key' is NULL if error
520 has occured. The application can freely use the `key' to whatever
521 purpose it needs. See lib/silcske/silcske.h for the definition of
522 the SilcSKEKeyMaterial structure. */
523 typedef void (*SilcKeyAgreementCallback)(SilcClient client,
524 SilcClientConnection conn,
525 SilcClientEntry client_entry,
526 SilcSKEKeyMaterial *key,
529 /* Sends key agreement request to the remote client indicated by the
530 `client_entry'. If the caller provides the `hostname' and the `port'
531 arguments then the library will bind the client to that hostname and
532 that port for the key agreement protocol. It also sends the `hostname'
533 and the `port' in the key agreement packet to the remote client. This
534 would indicate that the remote client may initiate the key agreement
535 protocol to the `hostname' on the `port'.
537 If the `hostname' and `port' is not provided then empty key agreement
538 packet is sent to the remote client. The remote client may reply with
539 the same packet including its hostname and port. If the library receives
540 the reply from the remote client the `key_agreement' client operation
541 callback will be called to verify whether the user wants to perform the
542 key agreement or not.
544 Note, that if the remote side decides not to initiate the key agreement
545 or decides not to reply with the key agreement packet then we cannot
546 perform the key agreement at all. If the key agreement protocol is
547 performed the `completion' callback with `context' will be called.
548 If remote side decides to ignore the request the `completion' will never
549 be called and the caller is responsible of freeing the `context' memory.
550 The application can do this by setting, for example, timeout. */
551 void silc_client_send_key_agreement(SilcClient client,
552 SilcClientConnection conn,
553 SilcClientEntry client_entry,
556 SilcKeyAgreementCallback completion,
559 /* This function can be called to unbind the hostname and the port for
560 the key agreement protocol. However, this function has effect only
561 before the key agreement protocol has been performed. After it has
562 been performed the library will automatically unbind the port. The
563 `client_entry' is the client to which we sent the key agreement
565 void silc_client_abort_key_agreement(SilcClient client,
566 SilcClientConnection conn,
567 SilcClientEntry client_entry);