Add an example how to connect to an UltraVNC-style repeater

UltraVNC offers an add-on to connect clients and servers via IDs with
a so-called repeater (e.g. to bridge firewalled clients and servers):

	http://www.uvnc.com/products/uvnc-repeater.html

This example demonstrates how to use that feature with a
LibVNCServer-based server.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

.gitignore

@@ -51,6 +51,7 @@ examples/fontsel
 examples/pnmshow
 examples/pnmshow24
 examples/regiontest
+examples/repeater
 examples/rotate
 examples/simple
 examples/simple15

examples/Makefile.am

@@ -23,5 +23,5 @@ noinst_HEADERS=radon.h rotatetemplate.c
 noinst_PROGRAMS=example pnmshow regiontest pnmshow24 fontsel \
 	vncev storepasswd colourmaptest simple simple15 $(MAC) \
 	$(FILETRANSFER) backchannel $(BLOOPTEST) camera rotate \
-	zippy
+	zippy repeater
 

examples/repeater.c

+/* This example shows how to connect to an UltraVNC repeater. */
+
+#include <rfb/rfb.h>
+
+int main(int argc,char** argv)
+{
+  char *repeaterHost;
+  int repeaterPort, sock;
+  char id[250];
+  rfbClientPtr cl;
+
+  int i,j;
+  uint16_t* f;
+
+  /* Parse command-line arguments */
+  if (argc < 3) {
+    fprintf(stderr,
+      "Usage: %s <id> <repeater-host> [<repeater-port>]\n", argv[0]);
+    exit(1);
+  }
+  snprintf(id, sizeof(id) - 1, "ID:%s", argv[1]);
+  repeaterHost = argv[2];
+  repeaterPort = argc < 4 ? 5500 : atoi(argv[3]);
+
+  /* The initialization is identical to simple15.c */
+  rfbScreenInfoPtr server=rfbGetScreen(&argc,argv,400,300,5,3,2);
+  if(!server)
+    return 0;
+  server->frameBuffer=(char*)malloc(400*300*2);
+  f=(uint16_t*)server->frameBuffer;
+  for(j=0;j<300;j++)
+    for(i=0;i<400;i++)
+      f[j*400+i]=/* red */ ((j*32/300) << 10) |
+		 /* green */ (((j+400-i)*32/700) << 5) |
+		 /* blue */ ((i*32/400));
+
+  /* Now for the repeater-specific part: */
+  server->port = -1; /* do not listen on any port */
+  server->ipv6port = -1; /* do not listen on any port */
+
+  sock = rfbConnectToTcpAddr(repeaterHost, repeaterPort);
+  if (sock < 0) {
+    perror("connect to repeater");
+    return 1;
+  }
+  if (write(sock, id, sizeof(id)) != sizeof(id)) {
+    perror("writing id");
+    return 1;
+  }
+  cl = rfbNewClient(server, sock);
+  if (!cl) {
+    perror("new client");
+    return 1;
+  }
+  cl->reverseConnection = 0;
+
+  /* Run the server */
+  rfbInitServer(server);
+  rfbRunEventLoop(server,-1,FALSE);
+
+  return 0;
+}