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);
67 /* Notify message to the client. The notify arguments are sent in the
68 same order as servers sends them. The arguments are same as received
69 from the server except for ID's. If ID is received application receives
70 the corresponding entry to the ID. For example, if Client ID is received
71 application receives SilcClientEntry. Also, if the notify type is
72 for channel the channel entry is sent to application (even if server
73 does not send it because client library gets the channel entry from
74 the Channel ID in the packet's header). */
75 void (*notify)(SilcClient client, SilcClientConnection conn,
76 SilcNotifyType type, ...);
78 /* Command handler. This function is called always in the command function.
79 If error occurs it will be called as well. `conn' is the associated
80 client connection. `cmd_context' is the command context that was
81 originally sent to the command. `success' is FALSE if error occured
82 during command. `command' is the command being processed. It must be
83 noted that this is not reply from server. This is merely called just
84 after application has called the command. Just to tell application
85 that the command really was processed. */
86 void (*command)(SilcClient client, SilcClientConnection conn,
87 SilcClientCommandContext cmd_context, int success,
90 /* Command reply handler. This function is called always in the command reply
91 function. If error occurs it will be called as well. Normal scenario
92 is that it will be called after the received command data has been parsed
93 and processed. The function is used to pass the received command data to
96 `conn' is the associated client connection. `cmd_payload' is the command
97 payload data received from server and it can be ignored. It is provided
98 if the application would like to re-parse the received command data,
99 however, it must be noted that the data is parsed already by the library
100 thus the payload can be ignored. `success' is FALSE if error occured.
101 In this case arguments are not sent to the application. The `status' is
102 the command reply status server returned. The `command' is the command
103 reply being processed. The function has variable argument list and each
104 command defines the number and type of arguments it passes to the
105 application (on error they are not sent). */
106 void (*command_reply)(SilcClient client, SilcClientConnection conn,
107 SilcCommandPayload cmd_payload, int success,
108 SilcCommand command, SilcCommandStatus status, ...);
110 /* Called to indicate that connection was either successfully established
111 or connecting failed. This is also the first time application receives
112 the SilcClientConnection objecet which it should save somewhere. */
113 void (*connect)(SilcClient client, SilcClientConnection conn, int success);
115 /* Called to indicate that connection was disconnected to the server. */
116 void (*disconnect)(SilcClient client, SilcClientConnection conn);
118 /* Find authentication method and authentication data by hostname and
119 port. The hostname may be IP address as well. The found authentication
120 method and authentication data is returned to `auth_meth', `auth_data'
121 and `auth_data_len'. The function returns TRUE if authentication method
122 is found and FALSE if not. `conn' may be NULL. */
123 int (*get_auth_method)(SilcClient client, SilcClientConnection conn,
124 char *hostname, unsigned short port,
125 SilcProtocolAuthMeth *auth_meth,
126 unsigned char **auth_data,
127 unsigned int *auth_data_len);
129 /* Verifies received public key. The public key has been received from
130 a server. If user decides to trust the key may be saved as trusted
131 server key for later use. If user does not trust the key this returns
132 FALSE. If everything is Ok this returns TRUE. */
133 int (*verify_server_key)(SilcClient client, SilcClientConnection conn,
134 unsigned char *pk, unsigned int pk_len,
135 SilcSKEPKType pk_type);
137 /* Ask (interact, that is) a passphrase from user. Returns the passphrase
139 unsigned char *(*ask_passphrase)(SilcClient client,
140 SilcClientConnection conn);
142 /* Notifies application that failure packet was received. This is called
143 if there is some protocol active in the client. The `protocol' is the
144 protocol context. The `failure' is opaque pointer to the failure
145 indication. Note, that the `failure' is protocol dependant and
146 application must explicitly cast it to correct type. Usually `failure'
147 is 32 bit failure type (see protocol specs for all protocol failure
149 void (*failure)(SilcClient client, SilcClientConnection conn,
150 SilcProtocol protocol, void *failure);
152 /* Asks whether the user would like to perform the key agreement protocol.
153 This is called after we have received an key agreement packet or an
154 reply to our key agreement packet. This returns TRUE if the user wants
155 the library to perform the key agreement protocol and FALSE if it is not
156 desired (application may start it later by calling the function
157 silc_client_perform_key_agreement). */
158 int (*key_agreement)(SilcClient client, SilcClientConnection conn,
159 SilcClientEntry client_entry, char *hostname,
161 } SilcClientOperations;
165 /******************************************************************************
167 SILC Client Library API
169 This is the API that is published by the SILC Client Library for the
170 applications. These functions are implemented in the SILC Client Library.
171 Application may freely call these functions from the library.
173 ******************************************************************************/
175 /* Initialization functions */
177 /* Allocates new client object. This has to be done before client may
178 work. After calling this one must call silc_client_init to initialize
179 the client. The `application' is application specific user data pointer
180 and caller must free it. */
181 SilcClient silc_client_alloc(SilcClientOperations *ops, void *application);
183 /* Frees client object and its internals. */
184 void silc_client_free(SilcClient client);
186 /* Initializes the client. This makes all the necessary steps to make
187 the client ready to be run. One must call silc_client_run to run the
188 client. Returns FALSE if error occured, TRUE otherwise. */
189 int silc_client_init(SilcClient client);
191 /* Runs the client. This starts the scheduler from the utility library.
192 When this functions returns the execution of the appliation is over. */
193 void silc_client_run(SilcClient client);
195 /* Stops the client. This is called to stop the client and thus to stop
197 void silc_client_stop(SilcClient client);
200 /* Connecting functions */
202 /* Connects to remote server. This is the main routine used to connect
203 to SILC server. Returns -1 on error and the created socket otherwise.
204 The `context' is user context that is saved into the SilcClientConnection
205 that is created after the connection is created. Note that application
206 may handle the connecting process outside the library. If this is the
207 case then this function is not used at all. When the connecting is
208 done the `connect' client operation is called. */
209 int silc_client_connect_to_server(SilcClient client, int port,
210 char *host, void *context);
212 /* Allocates and adds new connection to the client. This adds the allocated
213 connection to the connection table and returns a pointer to it. A client
214 can have multiple connections to multiple servers. Every connection must
215 be added to the client using this function. User data `context' may
216 be sent as argument. This function is normally used only if the
217 application performed the connecting outside the library. The library
218 however may use this internally. */
219 SilcClientConnection silc_client_add_connection(SilcClient client,
224 /* Removes connection from client. Frees all memory. */
225 void silc_client_del_connection(SilcClient client, SilcClientConnection conn);
227 /* Start SILC Key Exchange (SKE) protocol to negotiate shared secret
228 key material between client and server. This function can be called
229 directly if application is performing its own connecting and does not
230 use the connecting provided by this library. This function is normally
231 used only if the application performed the connecting outside the library.
232 The library however may use this internally. */
233 int silc_client_start_key_exchange(SilcClient client,
234 SilcClientConnection conn,
237 /* Closes connection to remote end. Free's all allocated data except
238 for some information such as nickname etc. that are valid at all time. */
239 void silc_client_close_connection(SilcClient client,
240 SilcClientConnection conn);
243 /* Message sending functions */
245 /* Sends packet to the `channel'. Packet to channel is always encrypted
246 differently from "normal" packets. SILC header of the packet is
247 encrypted with the next receiver's key and the rest of the packet is
248 encrypted with the channel specific key. Padding and HMAC is computed
249 with the next receiver's key. The `data' is the channel message. If
250 the `force_send' is TRUE then the packet is sent immediately. */
251 void silc_client_send_channel_message(SilcClient client,
252 SilcClientConnection conn,
253 SilcChannelEntry channel,
255 unsigned int data_len,
258 /* Sends private message to remote client. If private message key has
259 not been set with this client then the message will be encrypted using
260 normal session keys. Private messages are special packets in SILC
261 network hence we need this own function for them. This is similiar
262 to silc_client_packet_send_to_channel except that we send private
263 message. The `data' is the private message. If the `force_send' is
264 TRUE the packet is sent immediately. */
265 void silc_client_send_private_message(SilcClient client,
266 SilcClientConnection conn,
267 SilcClientEntry client_entry,
269 unsigned int data_len,
273 /* Client and Channel entry retrieval */
275 /* Callback function given to the silc_client_get_client function. The
276 found entries are allocated into the `clients' array. The array must
277 not be freed by the caller, the library will free it later. If the
278 `clients' is NULL, no such clients exist in the SILC Network. */
279 typedef void (*SilcGetClientCallback)(SilcClient client,
280 SilcClientConnection conn,
281 SilcClientEntry *clients,
282 unsigned int clients_count,
285 /* Finds client entry or entries by the `nickname' and `server'. The
286 completion callback will be called when the client entries has been found.
288 Note: this function is always asynchronous and resolves the client
289 information from the server. Thus, if you already know the client
290 information then use the silc_client_get_client_by_id function to
291 get the client entry since this function may be very slow and should
292 be used only to initially get the client entries. */
293 void silc_client_get_clients(SilcClient client,
294 SilcClientConnection conn,
297 SilcGetClientCallback completion,
300 /* Same as above function but does not resolve anything from the server.
301 This checks local cache and returns all clients from the cache. */
302 SilcClientEntry *silc_client_get_clients_local(SilcClient client,
303 SilcClientConnection conn,
306 unsigned int *clients_count);
308 /* Find entry for client by the client's ID. Returns the entry or NULL
309 if the entry was not found. */
310 SilcClientEntry silc_client_get_client_by_id(SilcClient client,
311 SilcClientConnection conn,
312 SilcClientID *client_id);
314 /* Same as above but will always resolve the information from the server.
315 Use this only if you know that you don't have the entry and the only
316 thing you know about the client is its ID. */
317 void silc_client_get_client_by_id_resolve(SilcClient client,
318 SilcClientConnection conn,
319 SilcClientID *client_id,
320 SilcGetClientCallback completion,
323 /* Finds entry for channel by the channel name. Returns the entry or NULL
324 if the entry was not found. It is found only if the client is joined
326 SilcChannelEntry silc_client_get_channel(SilcClient client,
327 SilcClientConnection conn,
331 /* Command management */
333 /* Allocate Command Context. The context is defined in `command.h' file.
334 The context is used by the library commands and applications should use
335 it as well. However, application may choose to use some own context
336 for its local commands. All library commands, however, must use this
338 SilcClientCommandContext silc_client_command_alloc();
340 /* Free command context and its internals */
341 void silc_client_command_free(SilcClientCommandContext ctx);
343 /* Duplicate Command Context by adding reference counter. The context won't
344 be free'd untill it hits zero. */
345 SilcClientCommandContext silc_client_command_dup(SilcClientCommandContext ctx);
347 /* Finds and returns a pointer to the command list. Return NULL if the
348 command is not found. See the `command.[ch]' for the command list. */
349 SilcClientCommand *silc_client_command_find(const char *name);
351 /* Generic function to send any command. The arguments must be sent already
352 encoded into correct form and in correct order. */
353 void silc_client_send_command(SilcClient client, SilcClientConnection conn,
354 SilcCommand command, unsigned short ident,
355 unsigned int argc, ...);
357 /* Pending Command callback destructor. This is called after calling the
358 pending callback or if error occurs while processing the pending command.
359 If error occurs then the callback won't be called at all, and only this
360 destructor is called. The `context' is the context given for the function
361 silc_client_command_pending. */
362 typedef void (*SilcClientPendingDestructor)(void *context);
364 /* Add new pending command to be executed when reply to a command has been
365 received. The `reply_cmd' is the command that will call the `callback'
366 with `context' when reply has been received. If `ident is non-zero
367 the `callback' will be executed when received reply with command
368 identifier `ident'. */
369 void silc_client_command_pending(SilcClientConnection conn,
370 SilcCommand reply_cmd,
371 unsigned short ident,
372 SilcClientPendingDestructor destructor,
373 SilcCommandCb callback,
377 /* Private Message key management */
379 /* Adds private message key to the client library. The key will be used to
380 encrypt all private message between the client and the remote client
381 indicated by the `client_entry'. If the `key' is NULL and the boolean
382 value `generate_key' is TRUE the library will generate random key.
383 The `key' maybe for example pre-shared-key, passphrase or similar.
384 The `cipher' MAY be provided but SHOULD be NULL to assure that the
385 requirements of the SILC protocol are met. The API, however, allows
386 to allocate any cipher.
388 It is not necessary to set key for normal private message usage. If the
389 key is not set then the private messages are encrypted using normal
390 session keys. Setting the private key, however, increases the security.
392 Returns FALSE if the key is already set for the `client_entry', TRUE
394 int silc_client_add_private_message_key(SilcClient client,
395 SilcClientConnection conn,
396 SilcClientEntry client_entry,
399 unsigned int key_len,
402 /* Same as above but takes the key material from the SKE key material
403 structure. This structure is received if the application uses the
404 silc_client_send_key_agreement to negotiate the key material. The
405 `cipher' SHOULD be provided as it is negotiated also in the SKE
407 int silc_client_add_private_message_key_ske(SilcClient client,
408 SilcClientConnection conn,
409 SilcClientEntry client_entry,
411 SilcSKEKeyMaterial *key);
413 /* Sends private message key payload to the remote client indicated by
414 the `client_entry'. If the `force_send' is TRUE the packet is sent
415 immediately. Returns FALSE if error occurs, TRUE otherwise. The
416 application should call this function after setting the key to the
419 Note that the key sent using this function is sent to the remote client
420 through the SILC network. The packet is protected using normal session
422 int silc_client_send_private_message_key(SilcClient client,
423 SilcClientConnection conn,
424 SilcClientEntry client_entry,
427 /* Removes the private message from the library. The key won't be used
428 after this to protect the private messages with the remote `client_entry'
429 client. Returns FALSE on error, TRUE otherwise. */
430 int silc_client_del_private_message_key(SilcClient client,
431 SilcClientConnection conn,
432 SilcClientEntry client_entry);
434 /* Structure to hold the list of private message keys. The array of this
435 structure is returned by the silc_client_list_private_message_keys
438 SilcClientEntry client_entry; /* The remote client entry */
439 char *cipher; /* The cipher name */
440 unsigned char *key; /* The original key, If the appliation
441 provided it. This is NULL if the
442 library generated the key or if
443 the SKE key material was used. */
444 unsigned int key_len; /* The key length */
445 } *SilcPrivateMessageKeys;
447 /* Returns array of set private message keys associated to the connection
448 `conn'. Returns allocated SilcPrivateMessageKeys array and the array
449 count to the `key_count' argument. The array must be freed by the caller
450 by calling the silc_client_free_private_message_keys function. Note:
451 the keys returned in the array is in raw format. It might not be desired
452 to show the keys as is. The application might choose not to show the keys
453 at all or to show the fingerprints of the keys. */
454 SilcPrivateMessageKeys
455 silc_client_list_private_message_keys(SilcClient client,
456 SilcClientConnection conn,
457 unsigned int *key_count);
459 /* Frees the SilcPrivateMessageKeys array returned by the function
460 silc_client_list_private_message_keys. */
461 void silc_client_free_private_message_keys(SilcPrivateMessageKeys keys,
462 unsigned int key_count);
465 /* Channel private key management */
467 /* Adds private key for channel. This may be set only if the channel's mode
468 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
469 mode is not set. When channel has private key then the messages are
470 encrypted using that key. All clients on the channel must also know the
471 key in order to decrypt the messages. However, it is possible to have
472 several private keys per one channel. In this case only some of the
473 clients on the channel may now the one key and only some the other key.
475 The private key for channel is optional. If it is not set then the
476 channel messages are encrypted using the channel key generated by the
477 server. However, setting the private key (or keys) for the channel
478 significantly adds security. If more than one key is set the library
479 will automatically try all keys at the message decryption phase. Note:
480 setting many keys slows down the decryption phase as all keys has to
481 be tried in order to find the correct decryption key. However, setting
482 a few keys does not have big impact to the decryption performace.
484 NOTE: that this is entirely local setting. The key set using this function
485 is not sent to the network at any phase.
487 NOTE: If the key material was originated by the SKE protocol (using
488 silc_client_send_key_agreement) then the `key' MUST be the
489 key->send_enc_key as this is dictated by the SILC protocol. However,
490 currently it is not expected that the SKE key material would be used
491 as channel private key. However, this API allows it. */
492 int silc_client_add_channel_private_key(SilcClient client,
493 SilcClientConnection conn,
494 SilcChannelEntry channel,
497 unsigned int key_len);
499 /* Removes all private keys from the `channel'. The old channel key is used
500 after calling this to protect the channel messages. Returns FALSE on
501 on error, TRUE otherwise. */
502 int silc_client_del_channel_private_keys(SilcClient client,
503 SilcClientConnection conn,
504 SilcChannelEntry channel);
506 /* Structure to hold one channel private key. */
508 char *cipher; /* The cipher name */
509 unsigned char *key; /* The key */
510 unsigned int key_len; /* The key length */
511 } *SilcChannelPrivateKey;
513 /* Removes and frees private key `key' from the channel `channel'. The `key'
514 is retrieved by calling the function silc_client_list_channel_private_keys.
515 The key is not used after this. If the key was last private key then the
516 old channel key is used hereafter to protect the channel messages. This
517 returns FALSE on error, TRUE otherwise. */
518 int silc_client_del_channel_private_key(SilcClient client,
519 SilcClientConnection conn,
520 SilcChannelEntry channel,
521 SilcChannelPrivateKey key);
523 /* Returns array (pointers) of private keys associated to the `channel'.
524 The caller must free the array by calling the function
525 silc_client_free_channel_private_keys. The pointers in the array may be
526 used to delete the specific key by giving the pointer as argument to the
527 function silc_client_del_channel_private_key. */
528 SilcChannelPrivateKey *
529 silc_client_list_channel_private_keys(SilcClient client,
530 SilcClientConnection conn,
531 SilcChannelEntry channel,
532 unsigned int key_count);
534 /* Frees the SilcChannelPrivateKey array. */
535 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
536 unsigned int key_count);
539 /* Key Agreement routines */
541 /* Key agreement callback that is called after the key agreement protocol
542 has been performed. This is called also if error occured during the
543 key agreement protocol. The `key' is the allocated key material and
544 the caller is responsible of freeing it. The `key' is NULL if error
545 has occured. The application can freely use the `key' to whatever
546 purpose it needs. See lib/silcske/silcske.h for the definition of
547 the SilcSKEKeyMaterial structure. */
548 typedef void (*SilcKeyAgreementCallback)(SilcClient client,
549 SilcClientConnection conn,
550 SilcClientEntry client_entry,
551 SilcSKEKeyMaterial *key,
554 /* Sends key agreement request to the remote client indicated by the
555 `client_entry'. If the caller provides the `hostname' and the `port'
556 arguments then the library will bind the client to that hostname and
557 that port for the key agreement protocol. It also sends the `hostname'
558 and the `port' in the key agreement packet to the remote client. This
559 would indicate that the remote client may initiate the key agreement
560 protocol to the `hostname' on the `port'.
562 If the `hostname' and `port' is not provided then empty key agreement
563 packet is sent to the remote client. The remote client may reply with
564 the same packet including its hostname and port. If the library receives
565 the reply from the remote client the `key_agreement' client operation
566 callback will be called to verify whether the user wants to perform the
567 key agreement or not.
569 NOTE: If the application provided the `hostname' and the `port' and the
570 remote side initiates the key agreement protocol it is not verified
571 from the user anymore whether the protocol should be executed or not.
572 By setting the `hostname' and `port' the user gives permission to
573 perform the protocol (we are responder in this case).
575 NOTE: If the remote side decides not to initiate the key agreement
576 or decides not to reply with the key agreement packet then we cannot
577 perform the key agreement at all. If the key agreement protocol is
578 performed the `completion' callback with the `context' will be called.
579 If remote side decides to ignore the request the `completion' will never
580 be called and the caller is responsible of freeing the `context' memory.
581 The application can do this by setting, for example, timeout. */
582 void silc_client_send_key_agreement(SilcClient client,
583 SilcClientConnection conn,
584 SilcClientEntry client_entry,
587 SilcKeyAgreementCallback completion,
590 /* Performs the actual key agreement protocol. Application may use this
591 to initiate the key agreement protocol. This can be called for example
592 after the application has received the `key_agreement' client operation,
593 and did not return TRUE from it.
595 The `hostname' is the remote hostname (or IP address) and the `port'
596 is the remote port. The `completion' callblack with the `context' will
597 be called after the key agreement protocol.
599 NOTE: If the application returns TRUE in the `key_agreement' client
600 operation the library will automatically start the key agreement. In this
601 case the application must not call this function. However, application
602 may choose to just ignore the `key_agreement' client operation (and
603 merely just print information about it on the screen) and call this
604 function when the user whishes to do so (by, for example, giving some
605 specific command). Thus, the API provides both, automatic and manual
606 initiation of the key agreement. Calling this function is the manual
607 initiation and returning TRUE in the `key_agreement' client operation
608 is the automatic initiation. */
609 void silc_client_perform_key_agreement(SilcClient client,
610 SilcClientConnection conn,
611 SilcClientEntry client_entry,
614 SilcKeyAgreementCallback completion,
617 /* This function can be called to unbind the hostname and the port for
618 the key agreement protocol. However, this function has effect only
619 before the key agreement protocol has been performed. After it has
620 been performed the library will automatically unbind the port. The
621 `client_entry' is the client to which we sent the key agreement
623 void silc_client_abort_key_agreement(SilcClient client,
624 SilcClientConnection conn,
625 SilcClientEntry client_entry);