1 /**
2  * @example backchannel-client.c
3  * A simple example of an RFB client
4  */
5 
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <time.h>
9 #include <errno.h>
10 #include <rfb/rfbclient.h>
11 
12 static void HandleRect(rfbClient* client, int x, int y, int w, int h) {
13 }
14 
15 /*
16  * The client part of the back channel extension example.
17  *
18  */
19 
20 #define rfbBackChannel 155
21 
22 typedef struct backChannelMsg {
23         uint8_t type;
24         uint8_t pad1;
25         uint16_t pad2;
26         uint32_t size;
27 } backChannelMsg;
28 
29 static void sendMessage(rfbClient* client, char* text)
30 {
31 	backChannelMsg msg;
32 	uint32_t length = strlen(text)+1;
33 
34 	msg.type = rfbBackChannel;
35 	msg.size = rfbClientSwap32IfLE(length);
36 	if(!WriteToRFBServer(client, (char*)&msg, sizeof(msg)) ||
37 			!WriteToRFBServer(client, text, length)) {
38 		rfbClientLog("enableBackChannel: write error (%d: %s)", errno, strerror(errno));
39 	}
40 }
41 
42 static rfbBool handleBackChannelMessage(rfbClient* client,
43 	rfbServerToClientMsg* message)
44 {
45 	backChannelMsg msg;
46 	char* text;
47 
48 	if(message->type != rfbBackChannel)
49 		return FALSE;
50 
51 	rfbClientSetClientData(client, sendMessage, sendMessage);
52 
53 	if(!ReadFromRFBServer(client, ((char*)&msg)+1, sizeof(msg)-1))
54 		return TRUE;
55 	msg.size = rfbClientSwap32IfLE(msg.size);
56 	text = malloc(msg.size);
57 	if(!ReadFromRFBServer(client, text, msg.size)) {
58 		free(text);
59 		return TRUE;
60 	}
61 
62 	rfbClientLog("got back channel message: %s\n", text);
63 	free(text);
64 
65 	return TRUE;
66 }
67 
68 static int backChannelEncodings[] = { rfbBackChannel, 0 };
69 
70 static rfbClientProtocolExtension backChannel = {
71 	backChannelEncodings,		/* encodings */
72 	NULL,				/* handleEncoding */
73 	handleBackChannelMessage,	/* handleMessage */
74 	NULL				/* next extension */
75 };
76 
77 int
78 main(int argc, char **argv)
79 {
80 	rfbClient* client = rfbGetClient(8,3,4);
81 
82 	client->GotFrameBufferUpdate = HandleRect;
83 	rfbClientRegisterExtension(&backChannel);
84 
85 	if (!rfbInitClient(client,&argc,argv))
86 		return 1;
87 
88 	while (1) {
89 		/* After each idle second, send a message */
90 		if(WaitForMessage(client,1000000)>0)
91 			HandleRFBServerMessage(client);
92 		else if(rfbClientGetClientData(client, sendMessage))
93 			sendMessage(client, "Dear Server,\n"
94 					"thank you for understanding "
95 					"back channel messages!");
96 	}
97 
98 	rfbClientCleanup(client);
99 
100 	return 0;
101 }
102 
103