1 <font size="+2">Using SILC Client Library</font>
3 <br /> <br /> <br />
4 <b>1.0 Introduction</b>
7 SILC Client library is a full featured SILC Client protocol implementation.
8 The library has been designed to be complete SILC client without actual
9 user interface. The library provides the API for the appliation which
10 it can use to implement generally whatever user interface it wants. The
11 SILC Client Library recides in the lib/silcclient/ directory. It uses
12 common and core compomnent of SILC protocol from the lib/silccore, SKE
13 from lib/silcske and general utility routines from lib/silcutil.
16 The `silcapi.h' file defines the function prototypes that application
17 must implement in order to be able to create the user interface with the
18 library. The idea is that the application can implement whatever user
19 interface routines in the functions and display the data whatever way
20 it wants. The library is entirely transparent to the user interface and
21 it does not include any user interface specific issues such as window
22 handling or item handling on the screen etc. These does not interest
23 the library. The `silcapi.h' also defines the client libary interface
24 the application can call. The interface includes for example functions
25 for sending channel and private messages, client and channel retrieval
26 and other utility functions.
28 <br /> <br /> <br />
29 <b>1.0.1 Including Library Headers</b>
32 Your application must include the following includes in your sources to
33 get access all SILC Client Library routines:
37 #include "silcincludes.h"<br />
38 #include "clientlibincludes.h"
42 If you are compiling with C++ compiler then you need to include the
48 #include "silcincludes.h"<br />
49 #include "clientlibincludes.h"<br &/>
54 <br /> <br /> <br />
55 <b>1.1 Creating Client</b>
58 The client is context or entity based, so several client entitites can
59 be created in the application if needed. However, it should be noted
60 that they are completely independent from each other and can be seen
61 as different applications. Usually only one client entity is needed
65 The client object is SilcClient which is usually allocated in following
69 <tt> SilcClient client = silc_client_alloc(&ops, params, context, version);</tt>
72 `ops' is the static structure of client operations that library will call.
73 `context' can be some application specific context that will be saved into
74 the SilcClient object. It is up to the caller to free this context.
75 SilcClient is always passed to the application thus the application
76 specific context can be retrieved from the SilcClient object. See
77 `client.h' file for detailed definition of SilcClient object.
80 `ops' can be defined for example as follows:
84 SilcClientOperations ops = {<br />
85 silc_say,<br />
86 silc_channel_message,<br />
87 silc_private_message,<br />
88 silc_notify,<br />
89 silc_command,<br />
90 silc_command_reply,<br />
91 silc_connect,<br />
92 silc_disconnect,<br />
93 silc_get_auth_method,<br />
94 silc_verify_public_key,<br />
95 silc_ask_passphrase,<br />
96 silc_failure,<br />
97 silc_key_agreement,<br />
102 Please see the `client_ops_example.c' source file in lib/silcclient/
103 directory for predefined structure and stub functions for your
104 convenience. It is provided for programmers so that they can copy
105 it and use it directly in their application.
108 <br /> <br /> <br />
109 <b>1.2 Initializing the Client</b>
112 The client must be initialized before running. However, there are also
113 some other tasks that must be done before initializing the client.
114 The following pointers must be set by the application before calling
115 the initializing function:
119 client->username<br />
120 client->hostname<br />
121 client->realname<br />
122 client->pkcs<br />
123 client->public_key<br />
124 client->private_key
128 You may also set client->nickname if you want. If it is set then the
129 library will change the nickname to that one after the client is connected
130 to the server. If not set, then server will initially give the nickname
131 which is same as the username.
134 After setting the pointers one must call:
137 <tt> silc_client_init(client);</tt>
140 which then initializes the client library for the `client'. If the
141 pointers mentioned above are not initialized the silc_client_init will
142 fail. The application should check the return value of the silc_client_init
146 <br /> <br /> <br />
147 <b>1.3 Running the Client</b>
150 The client is run by calling silc_client_run. The function will call
151 the scheduler from utility library that will be run until the program is
152 ended. When silc_client_run returns the application is ended. Thus,
153 to run the client, call:
156 <tt> silc_client_run(client);</tt>
159 Usually application may do some other initializations before calling
160 this function. For example before calling this function application
161 should initialize the user interface.
164 <br /> <br /> <br />
165 <b>1.3.1 Running the Client in GUI application</b>
168 Many GUI applications has their own main loop or event loop, which they
169 would like to use or are forced to use by the underlaying system. If you
170 are developing for example GUI application on Unix system, and you are
171 using GTK+ or QT as GUI library you would probably like to use their own
172 main loop. SILC Client can be run under external main loop as well. The
173 interface provides a function silc_client_run_one which will run the
174 client library once, and returns immediately. During that running it can
175 process incoming data and send outgoing data, but it is guaranteed that it
176 will not block the calling process.
179 It is suggested that you would call this function as many times in a
180 second as possible to provide smooth action for the client library. You
181 can use an timeout task, or an idle task provided by your GUI library to
182 accomplish this. After you have initialized the client library with
183 silc_client_init, you should register the timeout task or idle task that
184 will call the silc_client_run_one periodically. In the Toolkit package
185 there is GTK-- GUI example in silcer/ directory. That example calls the
186 silc_client_run_one every 50 milliseconds, and it should be sufficient for
190 For Win32 the silc_client_run can be used instead of using the Windows's
191 own event loop. However, if you would like to use the silc_client_run_one
192 also on Win32 systems it is possible.
195 <br /> <br /> <br />
196 <b>1.3.1.1 Running Client in GTK--</b>
199 Here is a short example how to run the SILC Client libary under the
200 Gnome/GTK--'s main loop:
204 gint YourClass::silc_scheduler()<br />
206 // Run the SILC client once, and return immediately. This function<br />
207 // is called every 50 milliseconds by the Gnome main loop, to process<br />
208 // SILC stuff. This function will read data, and write data to network,<br />
209 // etc. Makes the client library tick! :)<br />
210 silc_client_run_one(silc_client);<br />
211 return 1;<br />
216 then, during initialization of the SILC Client call:
220 // Setup SILC scheduler as timeout task. This will handle the SILC<br />
221 // client library every 50 milliseconds. It will actually make the<br />
222 // SILC client work on background.<br />
223 Gnome::Main::timeout.connect(slot(this, &YourClass::silc_scheduler), 50);<br />
227 This will call the function silc_scheduler every 50 millisecconds, which
228 on the otherhand will call silc_client_run_one, which will make the SILC
229 Client library work on the background of the GUI application.
232 <br /> <br /> <br />
233 <b>1.4 Creating Connection to Server</b>
236 Connection to remote SILC server is done by calling:
239 <tt> silc_client_connect_to_server(client, port, hostname, context);</tt>
242 The function will create the connection asynchronously to the server, ie.
243 the function will return before the actual connection is created. After
244 the connection is created the client->ops->connect operation is called.
247 Generally speaking the connections are associated with windows' on the
248 screen. IRC is usually implemented this way, however it is not the
249 necessary way to associate the client's connections. SilcClientConnection
250 object is provided by the library (and is always passed to the application)
251 that can be used in the application to associate the connection from the
252 library. Application specific context can be saved to the
253 SilcClientConnection object which then can be retrieved in the application,
254 thus perhaps associate the connection with what ever object in
255 application (window or something else).
258 <br /> <br /> <br />
259 <b>1.4.1 Using Own Connecting</b>
262 Application might not want to use silc_client_connect_to_server function
263 if it wants to perform its own connecting for some reason. In this case
264 application must call function silc_client_start_key_exchange after it
265 has created the connection by itself. This function starts the key
266 exhange protocol between the client and server and the library takes care
267 of everything after that.
270 After connection has been created application must call:
274 SilcClientConnection conn;
277 /* Add new connection to client */<br />
278 conn = silc_client_add_connection(client, hostname, port, context);
281 /* Start key exchange and let the library handle everything<br />
282 after this point on. */<br />
283 silc_client_start_key_exchange(client, conn, sock);
287 NOTE: These calls are performed only and only if application did not call
288 silc_client_connect_to_server function, but performed the connecting
292 <br /> <br /> <br />
293 <b>1.5 Example Client</b>
296 This section includes an example SILC client implementation in pseudo-like
297 C code. It creates and initializes the client and sets up an imaginary
298 user interface. The user will use the user interface then to create
299 the connections. The SilcClientOperations are expected to be implemented.
303 #include "silcincludes.h"
308 SilcClientOperations ops = {
310 silc_channel_message,
311 silc_private_message,
317 silc_get_auth_method,
318 silc_verify_public_key,
326 /* Allocate SILC client. The `silc_version_string' is defined
327 in includes/version.h file. */
328 client = silc_client_alloc(&ops, NULL, silc_version_string);
330 /* Register default ciphers, pkcs, hash funtions and hmacs. */
331 silc_cipher_register_default();
332 silc_pkcs_register_default();
333 silc_hash_register_default();
334 silc_hmac_register_default();
336 /* Set the mandatory pointers, read public and private key from
337 files (or somewhere) and return pointers and PKCS context. */
338 client->username = silc_get_username();
339 client->hostname = silc_net_localhost();
340 client->realname = silc_get_real_name();
341 client->pkcs = get_public_and_private_key(&client->public_key,
342 &client->private_key);
344 /* If the keys does not exist, create a key pair since we must
345 provide key pair to the library. */
347 generate_key_new_key_pair(client);
349 /* Iinitialize client */
350 if (!silc_client_init(client))
351 fatal_error("Could not initialize client");
353 /* Initialize user interface. The user interface can be generally
354 initialized at any phase, including before actually allocating
355 and initializing the client, if wished. */
359 /* Start the client. This will start the scheduler. At this phase
360 the user might have the user interface in front of him already.
361 He will use the user interface to create the connection to the
362 server for example. When this function returns the program is
364 silc_client_run(client);
366 /* Client is ended */