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 /* General definitions */
40 /* Key agreement callback that is called after the key agreement protocol
41 has been performed. This is called also if error occured during the
42 key agreement protocol. The `key' is the allocated key material and
43 the caller is responsible of freeing it. The `key' is NULL if error
44 has occured. The application can freely use the `key' to whatever
45 purpose it needs. See lib/silcske/silcske.h for the definition of
46 the SilcSKEKeyMaterial structure. */
47 typedef void (*SilcKeyAgreementCallback)(SilcClient client,
48 SilcClientConnection conn,
49 SilcClientEntry client_entry,
50 SilcSKEKeyMaterial *key,
53 /* Structure to hold the list of private message keys. The array of this
54 structure is returned by the silc_client_list_private_message_keys
57 SilcClientEntry client_entry; /* The remote client entry */
58 char *cipher; /* The cipher name */
59 unsigned char *key; /* The original key, If the appliation
60 provided it. This is NULL if the
61 library generated the key or if
62 the SKE key material was used. */
63 unsigned int key_len; /* The key length */
64 } *SilcPrivateMessageKeys;
66 /******************************************************************************
68 SILC Client Operations
70 These functions must be implemented by the application calling the SILC
71 client library. The client library can call these functions at any time.
73 To use this structure: define a static SilcClientOperations variable,
74 fill it and pass its pointer to silc_client_alloc function.
76 ******************************************************************************/
78 /* SILC Client Operations. These must be implemented by the application. */
80 /* Message sent to the application by library. `conn' associates the
81 message to a specific connection. `conn', however, may be NULL. */
82 void (*say)(SilcClient client, SilcClientConnection conn, char *msg, ...);
84 /* Message for a channel. The `sender' is the sender of the message
85 The `channel' is the channel. */
86 void (*channel_message)(SilcClient client, SilcClientConnection conn,
87 SilcClientEntry sender, SilcChannelEntry channel,
90 /* Private message to the client. The `sender' is the sender of the
92 void (*private_message)(SilcClient client, SilcClientConnection conn,
93 SilcClientEntry sender, char *msg);
95 /* Notify message to the client. The notify arguments are sent in the
96 same order as servers sends them. The arguments are same as received
97 from the server except for ID's. If ID is received application receives
98 the corresponding entry to the ID. For example, if Client ID is received
99 application receives SilcClientEntry. Also, if the notify type is
100 for channel the channel entry is sent to application (even if server
101 does not send it because client library gets the channel entry from
102 the Channel ID in the packet's header). */
103 void (*notify)(SilcClient client, SilcClientConnection conn,
104 SilcNotifyType type, ...);
106 /* Command handler. This function is called always in the command function.
107 If error occurs it will be called as well. `conn' is the associated
108 client connection. `cmd_context' is the command context that was
109 originally sent to the command. `success' is FALSE if error occured
110 during command. `command' is the command being processed. It must be
111 noted that this is not reply from server. This is merely called just
112 after application has called the command. Just to tell application
113 that the command really was processed. */
114 void (*command)(SilcClient client, SilcClientConnection conn,
115 SilcClientCommandContext cmd_context, int success,
116 SilcCommand command);
118 /* Command reply handler. This function is called always in the command reply
119 function. If error occurs it will be called as well. Normal scenario
120 is that it will be called after the received command data has been parsed
121 and processed. The function is used to pass the received command data to
124 `conn' is the associated client connection. `cmd_payload' is the command
125 payload data received from server and it can be ignored. It is provided
126 if the application would like to re-parse the received command data,
127 however, it must be noted that the data is parsed already by the library
128 thus the payload can be ignored. `success' is FALSE if error occured.
129 In this case arguments are not sent to the application. The `status' is
130 the command reply status server returned. The `command' is the command
131 reply being processed. The function has variable argument list and each
132 command defines the number and type of arguments it passes to the
133 application (on error they are not sent). */
134 void (*command_reply)(SilcClient client, SilcClientConnection conn,
135 SilcCommandPayload cmd_payload, int success,
136 SilcCommand command, SilcCommandStatus status, ...);
138 /* Called to indicate that connection was either successfully established
139 or connecting failed. This is also the first time application receives
140 the SilcClientConnection objecet which it should save somewhere. */
141 void (*connect)(SilcClient client, SilcClientConnection conn, int success);
143 /* Called to indicate that connection was disconnected to the server. */
144 void (*disconnect)(SilcClient client, SilcClientConnection conn);
146 /* Find authentication method and authentication data by hostname and
147 port. The hostname may be IP address as well. The found authentication
148 method and authentication data is returned to `auth_meth', `auth_data'
149 and `auth_data_len'. The function returns TRUE if authentication method
150 is found and FALSE if not. `conn' may be NULL. */
151 int (*get_auth_method)(SilcClient client, SilcClientConnection conn,
152 char *hostname, unsigned short port,
153 SilcProtocolAuthMeth *auth_meth,
154 unsigned char **auth_data,
155 unsigned int *auth_data_len);
157 /* Verifies received public key. The public key has been received from
158 a server. If user decides to trust the key may be saved as trusted
159 server key for later use. If user does not trust the key this returns
160 FALSE. If everything is Ok this returns TRUE. */
161 int (*verify_server_key)(SilcClient client, SilcClientConnection conn,
162 unsigned char *pk, unsigned int pk_len,
163 SilcSKEPKType pk_type);
165 /* Ask (interact, that is) a passphrase from user. Returns the passphrase
167 unsigned char *(*ask_passphrase)(SilcClient client,
168 SilcClientConnection conn);
170 /* Notifies application that failure packet was received. This is called
171 if there is some protocol active in the client. The `protocol' is the
172 protocol context. The `failure' is opaque pointer to the failure
173 indication. Note, that the `failure' is protocol dependant and
174 application must explicitly cast it to correct type. Usually `failure'
175 is 32 bit failure type (see protocol specs for all protocol failure
177 void (*failure)(SilcClient client, SilcClientConnection conn,
178 SilcProtocol protocol, void *failure);
180 /* Asks whether the user would like to perform the key agreement protocol.
181 This is called after we have received an key agreement packet or an
182 reply to our key agreement packet. This returns TRUE if the user wants
183 the library to perform the key agreement protocol and FALSE if it is not
184 desired (application may start it later by calling the function
185 silc_client_perform_key_agreement). If TRUE is returned also the
186 `completion' and `context' arguments must be set by the application. */
187 int (*key_agreement)(SilcClient client, SilcClientConnection conn,
188 SilcClientEntry client_entry, char *hostname,
190 SilcKeyAgreementCallback *completion,
192 } SilcClientOperations;
196 /******************************************************************************
198 SILC Client Library API
200 This is the API that is published by the SILC Client Library for the
201 applications. These functions are implemented in the SILC Client Library.
202 Application may freely call these functions from the library.
204 ******************************************************************************/
206 /* Initialization functions (client.c) */
208 /* Allocates new client object. This has to be done before client may
209 work. After calling this one must call silc_client_init to initialize
210 the client. The `application' is application specific user data pointer
211 and caller must free it. */
212 SilcClient silc_client_alloc(SilcClientOperations *ops, void *application);
214 /* Frees client object and its internals. */
215 void silc_client_free(SilcClient client);
217 /* Initializes the client. This makes all the necessary steps to make
218 the client ready to be run. One must call silc_client_run to run the
219 client. Returns FALSE if error occured, TRUE otherwise. */
220 int silc_client_init(SilcClient client);
222 /* Runs the client. This starts the scheduler from the utility library.
223 When this functions returns the execution of the appliation is over. */
224 void silc_client_run(SilcClient client);
226 /* Stops the client. This is called to stop the client and thus to stop
228 void silc_client_stop(SilcClient client);
231 /* Connecting functions (client.c) */
233 /* Connects to remote server. This is the main routine used to connect
234 to SILC server. Returns -1 on error and the created socket otherwise.
235 The `context' is user context that is saved into the SilcClientConnection
236 that is created after the connection is created. Note that application
237 may handle the connecting process outside the library. If this is the
238 case then this function is not used at all. When the connecting is
239 done the `connect' client operation is called. */
240 int silc_client_connect_to_server(SilcClient client, int port,
241 char *host, void *context);
243 /* Allocates and adds new connection to the client. This adds the allocated
244 connection to the connection table and returns a pointer to it. A client
245 can have multiple connections to multiple servers. Every connection must
246 be added to the client using this function. User data `context' may
247 be sent as argument. This function is normally used only if the
248 application performed the connecting outside the library. The library
249 however may use this internally. */
250 SilcClientConnection silc_client_add_connection(SilcClient client,
255 /* Removes connection from client. Frees all memory. */
256 void silc_client_del_connection(SilcClient client, SilcClientConnection conn);
258 /* Start SILC Key Exchange (SKE) protocol to negotiate shared secret
259 key material between client and server. This function can be called
260 directly if application is performing its own connecting and does not
261 use the connecting provided by this library. This function is normally
262 used only if the application performed the connecting outside the library.
263 The library however may use this internally. */
264 int silc_client_start_key_exchange(SilcClient client,
265 SilcClientConnection conn,
268 /* Closes connection to remote end. Free's all allocated data except
269 for some information such as nickname etc. that are valid at all time. */
270 void silc_client_close_connection(SilcClient client,
271 SilcClientConnection conn);
274 /* Message sending functions (client_channel.c and client_prvmsg.c) */
276 /* Sends packet to the `channel'. Packet to channel is always encrypted
277 differently from "normal" packets. SILC header of the packet is
278 encrypted with the next receiver's key and the rest of the packet is
279 encrypted with the channel specific key. Padding and HMAC is computed
280 with the next receiver's key. The `data' is the channel message. If
281 the `force_send' is TRUE then the packet is sent immediately.
283 If `key' is provided then that private key is used to encrypt the
284 channel message. If it is not provided, private keys has not been
285 set at all, the normal channel key is used automatically. If private
286 keys are set then the first key (the key that was added first as
287 private key) is used. */
288 void silc_client_send_channel_message(SilcClient client,
289 SilcClientConnection conn,
290 SilcChannelEntry channel,
291 SilcChannelPrivateKey key,
293 unsigned int data_len,
296 /* Sends private message to remote client. If private message key has
297 not been set with this client then the message will be encrypted using
298 normal session keys. Private messages are special packets in SILC
299 network hence we need this own function for them. This is similiar
300 to silc_client_packet_send_to_channel except that we send private
301 message. The `data' is the private message. If the `force_send' is
302 TRUE the packet is sent immediately. */
303 void silc_client_send_private_message(SilcClient client,
304 SilcClientConnection conn,
305 SilcClientEntry client_entry,
307 unsigned int data_len,
311 /* Client and Channel entry retrieval (idlist.c) */
313 /* Callback function given to the silc_client_get_client function. The
314 found entries are allocated into the `clients' array. The array must
315 not be freed by the caller, the library will free it later. If the
316 `clients' is NULL, no such clients exist in the SILC Network. */
317 typedef void (*SilcGetClientCallback)(SilcClient client,
318 SilcClientConnection conn,
319 SilcClientEntry *clients,
320 unsigned int clients_count,
323 /* Finds client entry or entries by the `nickname' and `server'. The
324 completion callback will be called when the client entries has been found.
326 Note: this function is always asynchronous and resolves the client
327 information from the server. Thus, if you already know the client
328 information then use the silc_client_get_client_by_id function to
329 get the client entry since this function may be very slow and should
330 be used only to initially get the client entries. */
331 void silc_client_get_clients(SilcClient client,
332 SilcClientConnection conn,
335 SilcGetClientCallback completion,
338 /* Same as above function but does not resolve anything from the server.
339 This checks local cache and returns all clients from the cache. */
340 SilcClientEntry *silc_client_get_clients_local(SilcClient client,
341 SilcClientConnection conn,
344 unsigned int *clients_count);
346 /* Gets client entries by the list of client ID's `client_id_list'. This
347 always resolves those client ID's it does not know yet from the server
348 so this function might take a while. The `client_id_list' is a list
349 of ID Payloads added one after other. JOIN command reply and USERS
350 command reply for example returns this sort of list. The `completion'
351 will be called after the entries are available. */
352 void silc_client_get_clients_by_list(SilcClient client,
353 SilcClientConnection conn,
354 unsigned int list_count,
355 SilcBuffer client_id_list,
356 SilcGetClientCallback completion,
359 /* Find entry for client by the client's ID. Returns the entry or NULL
360 if the entry was not found. */
361 SilcClientEntry silc_client_get_client_by_id(SilcClient client,
362 SilcClientConnection conn,
363 SilcClientID *client_id);
365 /* Same as above but will always resolve the information from the server.
366 Use this only if you know that you don't have the entry and the only
367 thing you know about the client is its ID. */
368 void silc_client_get_client_by_id_resolve(SilcClient client,
369 SilcClientConnection conn,
370 SilcClientID *client_id,
371 SilcGetClientCallback completion,
374 /* Finds entry for channel by the channel name. Returns the entry or NULL
375 if the entry was not found. It is found only if the client is joined
377 SilcChannelEntry silc_client_get_channel(SilcClient client,
378 SilcClientConnection conn,
382 /* Command management (command.c) */
384 /* Allocate Command Context. The context is defined in `command.h' file.
385 The context is used by the library commands and applications should use
386 it as well. However, application may choose to use some own context
387 for its local commands. All library commands, however, must use this
389 SilcClientCommandContext silc_client_command_alloc();
391 /* Free command context and its internals */
392 void silc_client_command_free(SilcClientCommandContext ctx);
394 /* Duplicate Command Context by adding reference counter. The context won't
395 be free'd untill it hits zero. */
396 SilcClientCommandContext silc_client_command_dup(SilcClientCommandContext ctx);
398 /* Finds and returns a pointer to the command list. Return NULL if the
399 command is not found. See the `command.[ch]' for the command list. */
400 SilcClientCommand *silc_client_command_find(const char *name);
402 /* Generic function to send any command. The arguments must be sent already
403 encoded into correct form and in correct order. */
404 void silc_client_send_command(SilcClient client, SilcClientConnection conn,
405 SilcCommand command, unsigned short ident,
406 unsigned int argc, ...);
408 /* Pending Command callback destructor. This is called after calling the
409 pending callback or if error occurs while processing the pending command.
410 If error occurs then the callback won't be called at all, and only this
411 destructor is called. The `context' is the context given for the function
412 silc_client_command_pending. */
413 typedef void (*SilcClientPendingDestructor)(void *context);
415 /* Add new pending command to be executed when reply to a command has been
416 received. The `reply_cmd' is the command that will call the `callback'
417 with `context' when reply has been received. If `ident is non-zero
418 the `callback' will be executed when received reply with command
419 identifier `ident'. */
420 void silc_client_command_pending(SilcClientConnection conn,
421 SilcCommand reply_cmd,
422 unsigned short ident,
423 SilcClientPendingDestructor destructor,
424 SilcCommandCb callback,
428 /* Private Message key management (client_prvmsg.c) */
430 /* Adds private message key to the client library. The key will be used to
431 encrypt all private message between the client and the remote client
432 indicated by the `client_entry'. If the `key' is NULL and the boolean
433 value `generate_key' is TRUE the library will generate random key.
434 The `key' maybe for example pre-shared-key, passphrase or similar.
435 The `cipher' MAY be provided but SHOULD be NULL to assure that the
436 requirements of the SILC protocol are met. The API, however, allows
437 to allocate any cipher.
439 It is not necessary to set key for normal private message usage. If the
440 key is not set then the private messages are encrypted using normal
441 session keys. Setting the private key, however, increases the security.
443 Returns FALSE if the key is already set for the `client_entry', TRUE
445 int silc_client_add_private_message_key(SilcClient client,
446 SilcClientConnection conn,
447 SilcClientEntry client_entry,
450 unsigned int key_len,
453 /* Same as above but takes the key material from the SKE key material
454 structure. This structure is received if the application uses the
455 silc_client_send_key_agreement to negotiate the key material. The
456 `cipher' SHOULD be provided as it is negotiated also in the SKE
458 int silc_client_add_private_message_key_ske(SilcClient client,
459 SilcClientConnection conn,
460 SilcClientEntry client_entry,
462 SilcSKEKeyMaterial *key);
464 /* Sends private message key payload to the remote client indicated by
465 the `client_entry'. If the `force_send' is TRUE the packet is sent
466 immediately. Returns FALSE if error occurs, TRUE otherwise. The
467 application should call this function after setting the key to the
470 Note that the key sent using this function is sent to the remote client
471 through the SILC network. The packet is protected using normal session
473 int silc_client_send_private_message_key(SilcClient client,
474 SilcClientConnection conn,
475 SilcClientEntry client_entry,
478 /* Removes the private message from the library. The key won't be used
479 after this to protect the private messages with the remote `client_entry'
480 client. Returns FALSE on error, TRUE otherwise. */
481 int silc_client_del_private_message_key(SilcClient client,
482 SilcClientConnection conn,
483 SilcClientEntry client_entry);
485 /* Returns array of set private message keys associated to the connection
486 `conn'. Returns allocated SilcPrivateMessageKeys array and the array
487 count to the `key_count' argument. The array must be freed by the caller
488 by calling the silc_client_free_private_message_keys function. Note:
489 the keys returned in the array is in raw format. It might not be desired
490 to show the keys as is. The application might choose not to show the keys
491 at all or to show the fingerprints of the keys. */
492 SilcPrivateMessageKeys
493 silc_client_list_private_message_keys(SilcClient client,
494 SilcClientConnection conn,
495 unsigned int *key_count);
497 /* Frees the SilcPrivateMessageKeys array returned by the function
498 silc_client_list_private_message_keys. */
499 void silc_client_free_private_message_keys(SilcPrivateMessageKeys keys,
500 unsigned int key_count);
503 /* Channel private key management (client_channel.c,
504 SilcChannelPrivateKey is defined in idlist.h) */
506 /* Adds private key for channel. This may be set only if the channel's mode
507 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
508 mode is not set. When channel has private key then the messages are
509 encrypted using that key. All clients on the channel must also know the
510 key in order to decrypt the messages. However, it is possible to have
511 several private keys per one channel. In this case only some of the
512 clients on the channel may know the one key and only some the other key.
514 The private key for channel is optional. If it is not set then the
515 channel messages are encrypted using the channel key generated by the
516 server. However, setting the private key (or keys) for the channel
517 significantly adds security. If more than one key is set the library
518 will automatically try all keys at the message decryption phase. Note:
519 setting many keys slows down the decryption phase as all keys has to
520 be tried in order to find the correct decryption key. However, setting
521 a few keys does not have big impact to the decryption performace.
523 NOTE: that this is entirely local setting. The key set using this function
524 is not sent to the network at any phase.
526 NOTE: If the key material was originated by the SKE protocol (using
527 silc_client_send_key_agreement) then the `key' MUST be the
528 key->send_enc_key as this is dictated by the SILC protocol. However,
529 currently it is not expected that the SKE key material would be used
530 as channel private key. However, this API allows it. */
531 int silc_client_add_channel_private_key(SilcClient client,
532 SilcClientConnection conn,
533 SilcChannelEntry channel,
537 unsigned int key_len);
539 /* Removes all private keys from the `channel'. The old channel key is used
540 after calling this to protect the channel messages. Returns FALSE on
541 on error, TRUE otherwise. */
542 int silc_client_del_channel_private_keys(SilcClient client,
543 SilcClientConnection conn,
544 SilcChannelEntry channel);
546 /* Removes and frees private key `key' from the channel `channel'. The `key'
547 is retrieved by calling the function silc_client_list_channel_private_keys.
548 The key is not used after this. If the key was last private key then the
549 old channel key is used hereafter to protect the channel messages. This
550 returns FALSE on error, TRUE otherwise. */
551 int silc_client_del_channel_private_key(SilcClient client,
552 SilcClientConnection conn,
553 SilcChannelEntry channel,
554 SilcChannelPrivateKey key);
556 /* Returns array (pointers) of private keys associated to the `channel'.
557 The caller must free the array by calling the function
558 silc_client_free_channel_private_keys. The pointers in the array may be
559 used to delete the specific key by giving the pointer as argument to the
560 function silc_client_del_channel_private_key. */
561 SilcChannelPrivateKey *
562 silc_client_list_channel_private_keys(SilcClient client,
563 SilcClientConnection conn,
564 SilcChannelEntry channel,
565 unsigned int *key_count);
567 /* Frees the SilcChannelPrivateKey array. */
568 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
569 unsigned int key_count);
572 /* Key Agreement routines (client_keyagr.c) */
574 /* Sends key agreement request to the remote client indicated by the
575 `client_entry'. If the caller provides the `hostname' and the `port'
576 arguments then the library will bind the client to that hostname and
577 that port for the key agreement protocol. It also sends the `hostname'
578 and the `port' in the key agreement packet to the remote client. This
579 would indicate that the remote client may initiate the key agreement
580 protocol to the `hostname' on the `port'. If port is zero then the
581 bound port is undefined (the operating system defines it).
583 If the `hostname' and `port' is not provided then empty key agreement
584 packet is sent to the remote client. The remote client may reply with
585 the same packet including its hostname and port. If the library receives
586 the reply from the remote client the `key_agreement' client operation
587 callback will be called to verify whether the user wants to perform the
588 key agreement or not.
590 NOTE: If the application provided the `hostname' and the `port' and the
591 remote side initiates the key agreement protocol it is not verified
592 from the user anymore whether the protocol should be executed or not.
593 By setting the `hostname' and `port' the user gives permission to
594 perform the protocol (we are responder in this case).
596 NOTE: If the remote side decides not to initiate the key agreement
597 or decides not to reply with the key agreement packet then we cannot
598 perform the key agreement at all. If the key agreement protocol is
599 performed the `completion' callback with the `context' will be called.
600 If remote side decides to ignore the request the `completion' will be
601 called after the specified timeout, `timeout_secs'.
603 NOTE: There can be only one active key agreement for one client entry.
604 Before setting new one, the old one must be finished (it is finished
605 after calling the completion callback) or the function
606 silc_client_abort_key_agreement must be called. */
607 void silc_client_send_key_agreement(SilcClient client,
608 SilcClientConnection conn,
609 SilcClientEntry client_entry,
612 unsigned long timeout_secs,
613 SilcKeyAgreementCallback completion,
616 /* Performs the actual key agreement protocol. Application may use this
617 to initiate the key agreement protocol. This can be called for example
618 after the application has received the `key_agreement' client operation,
619 and did not return TRUE from it.
621 The `hostname' is the remote hostname (or IP address) and the `port'
622 is the remote port. The `completion' callback with the `context' will
623 be called after the key agreement protocol.
625 NOTE: If the application returns TRUE in the `key_agreement' client
626 operation the library will automatically start the key agreement. In this
627 case the application must not call this function. However, application
628 may choose to just ignore the `key_agreement' client operation (and
629 merely just print information about it on the screen) and call this
630 function when the user whishes to do so (by, for example, giving some
631 specific command). Thus, the API provides both, automatic and manual
632 initiation of the key agreement. Calling this function is the manual
633 initiation and returning TRUE in the `key_agreement' client operation
634 is the automatic initiation. */
635 void silc_client_perform_key_agreement(SilcClient client,
636 SilcClientConnection conn,
637 SilcClientEntry client_entry,
640 SilcKeyAgreementCallback completion,
643 /* Same as above but application has created already the connection to
644 the remote host. The `sock' is the socket to the remote connection.
645 Application can use this function if it does not want the client library
646 to create the connection. */
647 void silc_client_perform_key_agreement_fd(SilcClient client,
648 SilcClientConnection conn,
649 SilcClientEntry client_entry,
651 SilcKeyAgreementCallback completion,
654 /* This function can be called to unbind the hostname and the port for
655 the key agreement protocol. However, this function has effect only
656 before the key agreement protocol has been performed. After it has
657 been performed the library will automatically unbind the port. The
658 `client_entry' is the client to which we sent the key agreement
660 void silc_client_abort_key_agreement(SilcClient client,
661 SilcClientConnection conn,
662 SilcClientEntry client_entry);