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, char *hostname,
163 } SilcClientOperations;
167 /******************************************************************************
169 SILC Client Library API
171 This is the API that is published by the SILC Client Library for the
172 applications. These functions are implemented in the SILC Client Library.
173 Application may freely call these functions from the library.
175 ******************************************************************************/
177 /* Initialization functions */
179 /* Allocates new client object. This has to be done before client may
180 work. After calling this one must call silc_client_init to initialize
181 the client. The `application' is application specific user data pointer
182 and caller must free it. */
183 SilcClient silc_client_alloc(SilcClientOperations *ops, void *application);
185 /* Frees client object and its internals. */
186 void silc_client_free(SilcClient client);
188 /* Initializes the client. This makes all the necessary steps to make
189 the client ready to be run. One must call silc_client_run to run the
190 client. Returns FALSE if error occured, TRUE otherwise. */
191 int silc_client_init(SilcClient client);
193 /* Runs the client. This starts the scheduler from the utility library.
194 When this functions returns the execution of the appliation is over. */
195 void silc_client_run(SilcClient client);
197 /* Stops the client. This is called to stop the client and thus to stop
199 void silc_client_stop(SilcClient client);
202 /* Connecting functions */
204 /* Connects to remote server. This is the main routine used to connect
205 to SILC server. Returns -1 on error and the created socket otherwise.
206 The `context' is user context that is saved into the SilcClientConnection
207 that is created after the connection is created. Note that application
208 may handle the connecting process outside the library. If this is the
209 case then this function is not used at all. When the connecting is
210 done the `connect' client operation is called. */
211 int silc_client_connect_to_server(SilcClient client, int port,
212 char *host, void *context);
214 /* Allocates and adds new connection to the client. This adds the allocated
215 connection to the connection table and returns a pointer to it. A client
216 can have multiple connections to multiple servers. Every connection must
217 be added to the client using this function. User data `context' may
218 be sent as argument. This function is normally used only if the
219 application performed the connecting outside the library. The library
220 however may use this internally. */
221 SilcClientConnection silc_client_add_connection(SilcClient client,
226 /* Removes connection from client. Frees all memory. */
227 void silc_client_del_connection(SilcClient client, SilcClientConnection conn);
229 /* Start SILC Key Exchange (SKE) protocol to negotiate shared secret
230 key material between client and server. This function can be called
231 directly if application is performing its own connecting and does not
232 use the connecting provided by this library. This function is normally
233 used only if the application performed the connecting outside the library.
234 The library however may use this internally. */
235 int silc_client_start_key_exchange(SilcClient client,
236 SilcClientConnection conn,
239 /* Closes connection to remote end. Free's all allocated data except
240 for some information such as nickname etc. that are valid at all time. */
241 void silc_client_close_connection(SilcClient client,
242 SilcClientConnection conn);
245 /* Message sending functions */
247 /* Sends packet to the `channel'. Packet to channel is always encrypted
248 differently from "normal" packets. SILC header of the packet is
249 encrypted with the next receiver's key and the rest of the packet is
250 encrypted with the channel specific key. Padding and HMAC is computed
251 with the next receiver's key. The `data' is the channel message. If
252 the `force_send' is TRUE then the packet is sent immediately. */
253 void silc_client_send_channel_message(SilcClient client,
254 SilcClientConnection conn,
255 SilcChannelEntry channel,
257 unsigned int data_len,
260 /* Sends private message to remote client. If private message key has
261 not been set with this client then the message will be encrypted using
262 normal session keys. Private messages are special packets in SILC
263 network hence we need this own function for them. This is similiar
264 to silc_client_packet_send_to_channel except that we send private
265 message. The `data' is the private message. If the `force_send' is
266 TRUE the packet is sent immediately. */
267 void silc_client_send_private_message(SilcClient client,
268 SilcClientConnection conn,
269 SilcClientEntry client_entry,
271 unsigned int data_len,
275 /* Client and Channel entry retrieval */
277 /* Callback function given to the silc_client_get_client function. The
278 found entries are allocated into the `clients' array. The array must
279 not be freed by the caller, the library will free it later. If the
280 `clients' is NULL, no such clients exist in the SILC Network. */
281 typedef void (*SilcGetClientCallback)(SilcClient client,
282 SilcClientConnection conn,
283 SilcClientEntry *clients,
284 unsigned int clients_count,
287 /* Finds client entry or entries by the `nickname' and `server'. The
288 completion callback will be called when the client entries has been found.
290 Note: this function is always asynchronous and resolves the client
291 information from the server. Thus, if you already know the client
292 information then use the silc_client_get_client_by_id function to
293 get the client entry since this function may be very slow and should
294 be used only to initially get the client entries. */
295 void silc_client_get_clients(SilcClient client,
296 SilcClientConnection conn,
299 SilcGetClientCallback completion,
302 /* Same as above function but does not resolve anything from the server.
303 This checks local cache and returns all clients from the cache. */
304 SilcClientEntry *silc_client_get_clients_local(SilcClient client,
305 SilcClientConnection conn,
308 unsigned int *clients_count);
310 /* Find entry for client by the client's ID. Returns the entry or NULL
311 if the entry was not found. */
312 SilcClientEntry silc_client_get_client_by_id(SilcClient client,
313 SilcClientConnection conn,
314 SilcClientID *client_id);
316 /* Finds entry for channel by the channel name. Returns the entry or NULL
317 if the entry was not found. It is found only if the client is joined
319 SilcChannelEntry silc_client_get_channel(SilcClient client,
320 SilcClientConnection conn,
324 /* Command management */
326 /* Allocate Command Context. The context is defined in `command.h' file.
327 The context is used by the library commands and applications should use
328 it as well. However, application may choose to use some own context
329 for its local commands. All library commands, however, must use this
331 SilcClientCommandContext silc_client_command_alloc();
333 /* Free command context and its internals */
334 void silc_client_command_free(SilcClientCommandContext ctx);
336 /* Duplicate Command Context by adding reference counter. The context won't
337 be free'd untill it hits zero. */
338 SilcClientCommandContext silc_client_command_dup(SilcClientCommandContext ctx);
340 /* Finds and returns a pointer to the command list. Return NULL if the
341 command is not found. See the `command.[ch]' for the command list. */
342 SilcClientCommand *silc_client_command_find(const char *name);
344 /* Generic function to send any command. The arguments must be sent already
345 encoded into correct form and in correct order. */
346 void silc_client_send_command(SilcClient client, SilcClientConnection conn,
347 SilcCommand command, unsigned short ident,
348 unsigned int argc, ...);
350 /* Pending Command callback destructor. This is called after calling the
351 pending callback or if error occurs while processing the pending command.
352 If error occurs then the callback won't be called at all, and only this
353 destructor is called. The `context' is the context given for the function
354 silc_client_command_pending. */
355 typedef void (*SilcClientPendingDestructor)(void *context);
357 /* Add new pending command to be executed when reply to a command has been
358 received. The `reply_cmd' is the command that will call the `callback'
359 with `context' when reply has been received. If `ident is non-zero
360 the `callback' will be executed when received reply with command
361 identifier `ident'. */
362 void silc_client_command_pending(SilcClientConnection conn,
363 SilcCommand reply_cmd,
364 unsigned short ident,
365 SilcClientPendingDestructor destructor,
366 SilcCommandCb callback,
370 /* Private Message key management */
372 /* Adds private message key to the client library. The key will be used to
373 encrypt all private message between the client and the remote client
374 indicated by the `client_entry'. If the `key' is NULL and the boolean
375 value `generate_key' is TRUE the library will generate random key.
376 The `key' maybe for example pre-shared-key, passphrase or similar.
378 It is not necessary to set key for normal private message usage. If the
379 key is not set then the private messages are encrypted using normal
380 session keys. Setting the private key, however, increases the security.
382 Note that the key set using this function is sent to the remote client
383 through the SILC network. The packet is protected using normal session
386 Returns FALSE if the key is already set for the `client_entry', TRUE
388 int silc_client_add_private_message_key(SilcClient client,
389 SilcClientConnection conn,
390 SilcClientConnection client_entry,
392 unsigned int key_len,
395 /* Same as above but takes the key material from the SKE key material
396 structure. This structure is received if the application uses the
397 silc_client_send_key_agreement to negotiate the key material. */
398 int silc_client_add_private_message_key_ske(SilcClient client,
399 SilcClientConnection conn,
400 SilcClientConnection client_entry,
401 SilcSKEKeyMaterial *key);
403 /* Removes the private message from the library. The key won't be used
404 after this to protect the private messages with the remote `client_entry'
405 client. Returns FALSE on error, TRUE otherwise. */
406 int silc_client_del_private_message_key(SilcClient client,
407 SilcClientConnection conn,
408 SilcClientEntry client_entry);
410 /* Structure to hold the list of private message keys. The array of this
411 structure is returned by the silc_client_list_private_message_keys
414 SilcClientEntry client_entry; /* The remote client entry */
415 unsigned char *key; /* The original key, If the appliation
416 provided it. This is NULL if the
417 library generated the key or if
418 the SKE key material was used. */
419 unsigned int key_len; /* The key length */
420 } *SilcPrivateMessageKeys;
422 /* Returns array of set private message keys associated to the connection
423 `conn'. Returns allocated SilcPrivateMessageKeys array and the array
424 count to the `key_count' argument. The array must be freed by the caller
425 by calling the silc_client_free_private_message_keys function. Note:
426 the keys returned in the array is in raw format. It might not be desired
427 to show the keys as is. The application might choose not to show the keys
428 at all or to show the fingerprints of the keys. */
429 SilcPrivateMessageKeys
430 silc_client_list_private_message_keys(SilcClient client,
431 SilcClientConnection conn,
432 unsigned int *key_count);
434 /* Frees the SilcPrivateMessageKeys array returned by the function
435 silc_client_list_private_message_keys. */
436 void silc_client_free_private_message_keys(SilcPrivateMessageKeys keys,
437 unsigned int key_count);
440 /* Channel private key management */
442 /* Adds private key for channel. This may be set only if the channel's mode
443 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
444 mode is not set. When channel has private key then the messages are
445 encrypted using that key. All clients on the channel must also know the
446 key in order to decrypt the messages. However, it is possible to have
447 several private keys per one channel. In this case only some of the
448 clients on the channel may now the one key and only some the other key.
450 The private key for channel is optional. If it is not set then the
451 channel messages are encrypted using the channel key generated by the
452 server. However, setting the private key (or keys) for the channel
453 significantly adds security. If more than one key is set the library
454 will automatically try all keys at the message decryption phase. Note:
455 setting many keys slows down the decryption phase as all keys has to
456 be tried in order to find the correct decryption key. However, setting
457 a few keys does not have big impact to the decryption performace.
459 NOTE: that this is entirely local setting. The key set using this function
460 is not sent to the network at any phase.
462 NOTE: If the key material was originated by the SKE protocol (using
463 silc_client_send_key_agreement) then the `key' MUST be the
464 key->send_enc_key as this is dictated by the SILC protocol. However,
465 currently it is not expected that the SKE key material would be used
466 as channel private key. However, this API allows it. */
467 int silc_client_add_channel_private_key(SilcClient client,
468 SilcClientConnection conn,
469 SilcChannelEntry channel,
471 unsigned int key_len);
473 /* Removes all private keys from the `channel'. The old channel key is used
474 after calling this to protect the channel messages. Returns FALSE on
475 on error, TRUE otherwise. */
476 int silc_client_del_channel_private_keys(SilcClient client,
477 SilcClientConnection conn,
478 SilcChannelEntry channel);
480 /* Structure to hold one channel private key. */
482 unsigned char *key; /* The key */
483 unsigned int key_len; /* The key length */
484 } *SilcChannelPrivateKey;
486 /* Removes and frees private key `key' from the channel `channel'. The `key'
487 is retrieved by calling the function silc_client_list_channel_private_keys.
488 The key is not used after this. If the key was last private key then the
489 old channel key is used hereafter to protect the channel messages. This
490 returns FALSE on error, TRUE otherwise. */
491 int silc_client_del_channel_private_key(SilcClient client,
492 SilcClientConnection conn,
493 SilcChannelEntry channel,
494 SilcChannelPrivateKey key);
496 /* Returns array (pointers) of private keys associated to the `channel'.
497 The caller must free the array by calling the function
498 silc_client_free_channel_private_keys. The pointers in the array may be
499 used to delete the specific key by giving the pointer as argument to the
500 function silc_client_del_channel_private_key. */
501 SilcChannelPrivateKey *
502 silc_client_list_channel_private_keys(SilcClient client,
503 SilcClientConnection conn,
504 SilcChannelEntry channel,
505 unsigned int key_count);
507 /* Frees the SilcChannelPrivateKey array. */
508 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
509 unsigned int key_count);
512 /* Key Agreement routines */
514 /* Key agreement callback that is called after the key agreement protocol
515 has been performed. This is called also if error occured during the
516 key agreement protocol. The `key' is the allocated key material and
517 the caller is responsible of freeing it. The `key' is NULL if error
518 has occured. The application can freely use the `key' to whatever
519 purpose it needs. See lib/silcske/silcske.h for the definition of
520 the SilcSKEKeyMaterial structure. */
521 typedef void (*SilcKeyAgreementCallback)(SilcClient client,
522 SilcClientConnection conn,
523 SilcClientEntry client_entry,
524 SilcSKEKeyMaterial *key,
527 /* Sends key agreement request to the remote client indicated by the
528 `client_entry'. If the caller provides the `hostname' and the `port'
529 arguments then the library will bind the client to that hostname and
530 that port for the key agreement protocol. It also sends the `hostname'
531 and the `port' in the key agreement packet to the remote client. This
532 would indicate that the remote client may initiate the key agreement
533 protocol to the `hostname' on the `port'.
535 If the `hostname' and `port' is not provided then empty key agreement
536 packet is sent to the remote client. The remote client may reply with
537 the same packet including its hostname and port. If the library receives
538 the reply from the remote client the `key_agreement' client operation
539 callback will be called to verify whether the user wants to perform the
540 key agreement or not.
542 Note, that if the remote side decides not to initiate the key agreement
543 or decides not to reply with the key agreement packet then we cannot
544 perform the key agreement at all. If the key agreement protocol is
545 performed the `completion' callback with `context' will be called.
546 If remote side decides to ignore the request the `completion' will never
547 be called and the caller is responsible of freeing the `context' memory.
548 The application can do this by setting, for example, timeout. */
549 void silc_client_send_key_agreement(SilcClient client,
550 SilcClientConnection conn,
551 SilcClientEntry client_entry,
554 SilcKeyAgreementCallback completion,
557 /* This function can be called to unbind the hostname and the port for
558 the key agreement protocol. However, this function has effect only
559 before the key agreement protocol has been performed. After it has
560 been performed the library will automatically unbind the port. The
561 `client_entry' is the client to which we sent the key agreement
563 void silc_client_abort_key_agreement(SilcClient client,
564 SilcClientConnection conn,
565 SilcClientEntry client_entry);