2 SILC Client Library Manual
8 SILC Client library is a full featured SILC Client protocolimplementation.
9 The library has been designed to be complete SILC client without actual
10 user interface. The library provides the API for the appliation which
11 it can use to implement generally whatever user interface it wants. The
12 SILC Client Library recides in the lib/silcclient/ directory. It uses
13 common and core compomnent of SILC protocol from the lib/silccore, SKE
14 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.
29 1.0.1 Including Library Headers
31 Your application must include the following includes in your sources to
32 get access all SILC Client Library routines:
34 #include "silcincludes.h"
35 #include "clientlibincludes.h"
37 If you are compiling with C++ compiler then you need to include the
41 #include "silcincludes.h"
42 #include "clientlibincludes.h"
48 The client is context or entity based, so several client entitites can
49 be created in the application if needed. However, it should be noted
50 that they are completely independent from each other and can be seen
51 as different applications. Usually only one client entity is needed
54 The client object is SilcClient which is usually allocated in following
57 SilcClient client = silc_client_alloc(&ops, context, version);
59 `ops' is the static structure of client operations that library will call.
60 `context' can be some application specific context that will be saved into
61 the SilcClient object. It is up to the caller to free this context.
62 SilcClient is always passed to the application thus the application
63 specific context can be retrieved from the SilcClient object. See
64 `client.h' file for detailed definition of SilcClient object.
66 `ops' can be defined for example as follows:
68 SilcClientOperations ops = {
78 silc_verify_public_key,
84 Please see the `client_ops_example.h' header file in lib/silcclient/
85 directory for predefined structure and stub functions for your
86 convenince. It is provided for programmers so that they can copy
87 it and use it directly in their application.
90 1.2 Initializing the Client
92 The client must be initialized before running. However, there are also
93 some other tasks that must be done before initializing the client.
94 The following pointers must be set by the application before calling
95 the initializing function:
104 You may also set client->nickname if you want. If it is set then the
105 library will change the nickname to that one after the client is connected
106 to the server. If not set, then server will initially give the nickname
107 which is same as the username.
109 After setting the pointers one must call:
111 silc_client_init(client);
113 which then initializes the client library for the `client'. If the
114 pointers mentioned above are not initialized the silc_client_init will
115 fail. The application should check the return value of the silc_client_init
119 1.3 Running the Client
121 The client is run by calling silc_client_run. The function will call
122 the scheduler from utility library that will be run until the program is
123 ended. When silc_client_run returns the application is ended. Thus,
124 to run the client, call:
126 silc_client_run(client);
128 Usually application may do some other initializations before calling
129 this function. For example before calling this function application
130 should initialize the user interface.
133 1.3.1 Running the Client in GUI application
135 Many GUI applications has their own main loop or event loop, which they
136 would like to use or are forced to use by the underlaying system. If you
137 are developing for example GUI application on Unix system, and you are
138 using GTK+ or QT as GUI library you would probably like to use their own
139 main loop. SILC Client can be run under external main loop as well. The
140 interface provides a function silc_client_run_one which will run the
141 client library once, and returns immediately. During that running it can
142 process incoming data and send outgoing data, but it is guaranteed that it
143 will not block the calling process.
145 It is suggested that you would call this function as many times in a
146 second as possible to provide smooth action for the client library. You
147 can use an timeout task, or an idle task provided by your GUI library to
148 accomplish this. After you have initialized the client library with
149 silc_client_init, you should register the timeout task or idle task that
150 will call the silc_client_run_one periodically. In the Toolkit package
151 there is GTK-- GUI example in silcer/ directory. That example calls the
152 silc_client_run_one every 50 milliseconds, and it should be sufficient for
155 For Win32 the silc_client_run can be used instead of using the Windows's
156 own event loop. However, if you would like to use the silc_client_run_one
157 also on Win32 systems it is possible.
160 1.3.1.1 Running Client in GTK--
162 Here is a short example how to run the SILC Client libary under the
163 Gnome/GTK--'s main loop:
165 gint YourClass::silc_scheduler()
167 // Run the SILC client once, and return immediately. This function
168 // is called every 50 milliseconds by the Gnome main loop, to process
169 // SILC stuff. This function will read data, and write data to network,
170 // etc. Makes the client library tick! :)
171 silc_client_run_one(silc_client);
175 then, during initialization of the SILC Client call:
177 // Setup SILC scheduler as timeout task. This will handle the SILC
178 // client library every 50 milliseconds. It will actually make the
179 // SILC client work on background.
180 Gnome::Main::timeout.connect(slot(this, &YourClass::silc_scheduler), 50);
182 This will call the function silc_scheduler every 50 millisecconds, which
183 on the otherhand will call silc_client_run_one, which will make the SILC
184 Client library work on the background of the GUI application.
187 1.4 Creating Connection to Server
189 Connection to remote SILC server is done by calling:
191 silc_client_connect_to_server(client, port, hostname, context);
193 The function will create the connection asynchronously to the server, ie.
194 the function will return before the actual connection is created. After
195 the connection is created the client->ops->connect operation is called.
197 Generally speaking the connections are associated with windows' on the
198 screen. IRC is usually implemented this way, however it is not the
199 necessary way to associate the client's connections. SilcClientConnection
200 object is provided by the library (and is always passed to the application)
201 that can be used in the application to associate the connection from the
202 library. Application specific context can be saved to the
203 SilcClientConnection object which then can be retrieved in the application,
204 thus perhaps associate the connection with what ever object in
205 application (window or something else).
208 1.4.1 Using Own Connecting
210 Application might not want to use silc_client_connect_to_server function
211 if it wants to perform its own connecting for some reason. In this case
212 application must call function silc_client_start_key_exchange after it
213 has created the connection by itself. This function starts the key
214 exhange protocol between the client and server and the library takes care
215 of everything after that.
217 After connection has been created application must call:
219 SilcClientConnection conn;
221 /* Add new connection to client */
222 conn = silc_client_add_connection(client, hostname, port, context);
224 /* Start key exchange and let the library handle everything
225 after this point on. */
226 silc_client_start_key_exchange(client, conn, sock);
228 NOTE: These calls are performed only and only if application did not call
229 silc_client_connect_to_server function, but performed the connecting
235 This section includes an example SILC client implementation in pseudo-like
236 C code. It creates and initializes the client and sets up an imaginary
237 user interface. The user will use the user interface then to create
238 the connections. The SilcClientOperations are expected to be implemented.
240 #include "silcincludes.h"
245 SilcClientOperations ops = {
247 silc_channel_message,
248 silc_private_message,
254 silc_get_auth_method,
255 silc_verify_public_key,
263 /* Allocate SILC client. The `silc_version_string' is defined
264 in includes/version.h file. */
265 client = silc_client_alloc(&ops, NULL, silc_version_string);
267 /* Register default ciphers, pkcs, hash funtions and hmacs. */
268 silc_cipher_register_default();
269 silc_pkcs_register_default();
270 silc_hash_register_default();
271 silc_hmac_register_default();
273 /* Set the mandatory pointers, read public and private key from
274 files (or somewhere) and return pointers and PKCS context. */
275 client->username = silc_get_username();
276 client->hostname = silc_net_localhost();
277 client->realname = silc_get_real_name();
278 client->pkcs = get_public_and_private_key(&client->public_key,
279 &client->private_key);
281 /* If the keys does not exist, create a key pair since we must
282 provide key pair to the library. */
284 generate_key_new_key_pair(client);
286 /* Iinitialize client */
287 if (!silc_client_init(client))
288 fatal_error("Could not initialize client");
290 /* Initialize user interface. The user interface can be generally
291 initialized at any phase, including before actually allocating
292 and initializing the client, if wished. */
296 /* Start the client. This will start the scheduler. At this phase
297 the user might have the user interface in front of him already.
298 He will use the user interface to create the connection to the
299 server for example. When this function returns the program is
301 silc_client_run(client);
303 /* Client is ended */