libvnc[server|client]: implement xvp VNC extension.

This implements the xvp VNC extension, which is described in the
community version of the RFB protocol:
http://tigervnc.sourceforge.net/cgi-bin/rfbproto
It is also mentioned in the official RFB protocol.

libvncclient/rfbproto.c

@@ -1230,6 +1230,9 @@ SetFormatAndEncodings(rfbClient* client)
   if (se->nEncodings < MAX_ENCODINGS)
     encs[se->nEncodings++] = rfbClientSwap32IfLE(rfbEncodingServerIdentity);
 
+  /* xvp */
+  if (se->nEncodings < MAX_ENCODINGS)
+    encs[se->nEncodings++] = rfbClientSwap32IfLE(rfbEncodingXvp);
 
   /* client extensions */
   for(e = rfbClientExtensions; e; e = e->next)
@@ -1394,6 +1397,37 @@ rfbBool PermitServerInput(rfbClient* client, int enabled)
 }
 
 
+/*
+ * send xvp client message
+ * A client supporting the xvp extension sends this to request that the server initiate
+ * a clean shutdown, clean reboot or abrupt reset of the system whose framebuffer the
+ * client is displaying.
+ *
+ * only version 1 is defined in the protocol specs
+ *
+ * possible values for code are:
+ *   rfbXvp_Shutdown
+ *   rfbXvp_Reboot
+ *   rfbXvp_Reset
+ */
+
+rfbBool SendXvpMsg(rfbClient* client, uint8_t version, uint8_t code)
+{
+    rfbXvpMsg xvp;
+
+    if (!SupportsClient2Server(client, rfbXvp)) return TRUE;
+    xvp.type = rfbXvp;
+    xvp.pad = 0;
+    xvp.version = version;
+    xvp.code = code;
+
+    if (!WriteToRFBServer(client, (char *)&xvp, sz_rfbXvpMsg))
+        return FALSE;
+
+    return TRUE;
+}
+
+
 /*
  * SendPointerEvent.
  */
@@ -1984,6 +2018,24 @@ HandleRFBServerMessage(rfbClient* client)
       break;
   }
 
+  case rfbXvp:
+  {
+    if (!ReadFromRFBServer(client, ((char *)&msg) + 1,
+                           sz_rfbXvpMsg -1))
+      return FALSE;
+
+    SetClient2Server(client, rfbXvp);
+    /* technically, we only care what we can *send* to the server
+     * but, we set Server2Client Just in case it ever becomes useful
+     */
+    SetServer2Client(client, rfbXvp);
+
+    if(client->HandleXvpMsg)
+      client->HandleXvpMsg(client, msg.xvp.version, msg.xvp.code);
+
+    break;
+  }
+
   case rfbResizeFrameBuffer:
   {
     if (!ReadFromRFBServer(client, ((char *)&msg) + 1,

libvncserver/main.c

@@ -901,6 +901,7 @@ rfbScreenInfoPtr rfbGetScreen(int* argc,char** argv,
    screen->displayHook = NULL;
    screen->displayFinishedHook = NULL;
    screen->getKeyboardLedStateHook = NULL;
+   screen->xvpHook = NULL;
 
    /* initialize client list and iterator mutex */
    rfbClientListInit(screen);

libvncserver/rfbserver.c

@@ -874,6 +874,7 @@ rfbSendSupportedMessages(rfbClientPtr cl)
     /*rfbSetBit(msgs.client2server, rfbTextChat);        */
     /*rfbSetBit(msgs.client2server, rfbKeyFrameRequest); */
     rfbSetBit(msgs.client2server, rfbPalmVNCSetScaleFactor);
+    rfbSetBit(msgs.client2server, rfbXvp);
 
     rfbSetBit(msgs.server2client, rfbFramebufferUpdate);
     rfbSetBit(msgs.server2client, rfbSetColourMapEntries);
@@ -882,6 +883,7 @@ rfbSendSupportedMessages(rfbClientPtr cl)
     rfbSetBit(msgs.server2client, rfbResizeFrameBuffer);
     /*rfbSetBit(msgs.server2client, rfbKeyFrameUpdate);  */
     rfbSetBit(msgs.server2client, rfbPalmVNCReSizeFrameBuffer);
+    rfbSetBit(msgs.server2client, rfbXvp);
 
     memcpy(&cl->updateBuf[cl->ublen], (char *)&msgs, sz_rfbSupportedMessages);
     cl->ublen += sz_rfbSupportedMessages;
@@ -1027,6 +1029,33 @@ rfbSendServerIdentity(rfbClientPtr cl)
     return TRUE;
 }
 
+/*
+ * Send an xvp server message
+ */
+
+rfbBool
+rfbSendXvp(rfbClientPtr cl, uint8_t version, uint8_t code)
+{
+    rfbXvpMsg xvp;
+
+    xvp.type = rfbXvp;
+    xvp.pad = 0;
+    xvp.version = version;
+    xvp.code = code;
+
+    LOCK(cl->sendMutex);
+    if (rfbWriteExact(cl, (char *)&xvp, sz_rfbXvpMsg) < 0) {
+      rfbLogPerror("rfbSendXvp: write");
+      rfbCloseClient(cl);
+    }
+    UNLOCK(cl->sendMutex);
+
+    rfbStatRecordMessageSent(cl, rfbXvp, sz_rfbXvpMsg, sz_rfbXvpMsg);
+
+    return TRUE;
+}
+
+
 rfbBool rfbSendTextChatMessage(rfbClientPtr cl, uint32_t length, char *buffer)
 {
     rfbTextChatMsg tc;
@@ -1985,6 +2014,14 @@ rfbProcessClientNormalMessage(rfbClientPtr cl)
                   cl->enableServerIdentity = TRUE;
                 }
                 break;
+	    case rfbEncodingXvp:
+	        rfbLog("Enabling Xvp protocol extension for client "
+		        "%s\n", cl->host);
+		if (!rfbSendXvp(cl, 1, rfbXvp_Init)) {
+		  rfbCloseClient(cl);
+		  return;
+		}
+                break;
             default:
 #ifdef LIBVNCSERVER_HAVE_LIBZ
 		if ( enc >= (uint32_t)rfbEncodingCompressLevel0 &&
@@ -2368,6 +2405,28 @@ rfbProcessClientNormalMessage(rfbClientPtr cl)
       rfbSendNewScaleSize(cl);
       return;
 
+    case rfbXvp:
+
+      if ((n = rfbReadExact(cl, ((char *)&msg) + 1,
+          sz_rfbXvpMsg - 1)) <= 0) {
+          if (n != 0)
+            rfbLogPerror("rfbProcessClientNormalMessage: read");
+          rfbCloseClient(cl);
+          return;
+      }
+      rfbStatRecordMessageRcvd(cl, msg.type, sz_rfbXvpMsg, sz_rfbXvpMsg);
+
+      /* only version when is defined, so echo back a fail */
+      if(msg.xvp.version != 1) {
+	rfbSendXvp(cl, msg.xvp.version, rfbXvp_Fail);
+      }
+      else {
+	/* if the hook exists and fails, send a fail msg */
+	if(cl->screen->xvpHook && !cl->screen->xvpHook(cl, msg.xvp.version, msg.xvp.code))
+	  rfbSendXvp(cl, 1, rfbXvp_Fail);
+      }
+      return;
+
     default:
 	{
 	    rfbExtensionData *e,*next;

libvncserver/stats.c

@@ -55,6 +55,7 @@ char *messageNameServer2Client(uint32_t type, char *buf, int len) {
     case rfbFileTransfer:             snprintf(buf, len, "FileTransfer"); break;
     case rfbTextChat:                 snprintf(buf, len, "TextChat"); break;
     case rfbPalmVNCReSizeFrameBuffer: snprintf(buf, len, "PalmVNCReSize"); break;
+    case rfbXvp:                      snprintf(buf, len, "XvpServerMessage"); break;
     default:
         snprintf(buf, len, "svr2cli-0x%08X", 0xFF);
     }
@@ -78,6 +79,7 @@ char *messageNameClient2Server(uint32_t type, char *buf, int len) {
     case rfbTextChat:                 snprintf(buf, len, "TextChat"); break;
     case rfbKeyFrameRequest:          snprintf(buf, len, "KeyFrameRequest"); break;
     case rfbPalmVNCSetScaleFactor:    snprintf(buf, len, "PalmVNCSetScale"); break;
+    case rfbXvp:                      snprintf(buf, len, "XvpClientMessage"); break;
     default:
         snprintf(buf, len, "cli2svr-0x%08X", type);
 

rfb/rfb.h

@@ -139,6 +139,7 @@ typedef void (*rfbDisplayHookPtr)(struct _rfbClientRec* cl);
 typedef void (*rfbDisplayFinishedHookPtr)(struct _rfbClientRec* cl, int result);
 /* support the capability to view the caps/num/scroll states of the X server */
 typedef int  (*rfbGetKeyboardLedStateHookPtr)(struct _rfbScreenInfo* screen);
+typedef rfbBool (*rfbXvpHookPtr)(struct _rfbClientRec* cl, uint8_t, uint8_t);
 /* If x==1 and y==1 then set the whole display
  * else find the window underneath x and y and set the framebuffer to the dimensions
  * of that window
@@ -356,6 +357,8 @@ typedef struct _rfbScreenInfo
 
     /* displayFinishedHook is called just after a frame buffer update */
     rfbDisplayFinishedHookPtr displayFinishedHook;
+    /* xvpHook is called to handle an xvp client message */
+    rfbXvpHookPtr xvpHook;
 } rfbScreenInfo, *rfbScreenInfoPtr;
 
 

rfb/rfbclient.h

@@ -136,6 +136,7 @@ typedef union _rfbCredential
 struct _rfbClient;
 
 typedef void (*HandleTextChatProc)(struct _rfbClient* client, int value, char *text);
+typedef void (*HandleXvpMsgProc)(struct _rfbClient* client, uint8_t version, uint8_t opcode);
 typedef void (*HandleKeyboardLedStateProc)(struct _rfbClient* client, int value, int pad);
 typedef rfbBool (*HandleCursorPosProc)(struct _rfbClient* client, int x, int y);
 typedef void (*SoftCursorLockAreaProc)(struct _rfbClient* client, int x, int y, int w, int h);
@@ -316,6 +317,9 @@ typedef struct _rfbClient {
 
         /* the QoS IP DSCP for this client */
         int QoS_DSCP;
+
+        /* hook to handle xvp server messages */
+	HandleXvpMsgProc           HandleXvpMsg;
 } rfbClient;
 
 /* cursor.c */
@@ -352,6 +356,7 @@ extern rfbBool TextChatOpen(rfbClient* client);
 extern rfbBool TextChatClose(rfbClient* client);
 extern rfbBool TextChatFinish(rfbClient* client);
 extern rfbBool PermitServerInput(rfbClient* client, int enabled);
+extern rfbBool SendXvpMsg(rfbClient* client, uint8_t version, uint8_t code);
 
 extern void PrintPixelFormat(rfbPixelFormat *format);
 

rfb/rfbproto.h

@@ -106,7 +106,7 @@ typedef uint32_t in_addr_t;
 #define                INADDR_NONE     ((in_addr_t) 0xffffffff)
 #endif
 
-#define MAX_ENCODINGS 20
+#define MAX_ENCODINGS 21
 
 /*****************************************************************************
  *
@@ -405,6 +405,8 @@ typedef struct {
 #define rfbKeyFrameRequest 12
 /* PalmVNC 1.4 & 2.0 SetScale Factor message */
 #define rfbPalmVNCSetScaleFactor 0xF
+/* Xvp message - bidirectional */
+#define rfbXvp 250
 
 
 
@@ -439,6 +441,9 @@ typedef struct {
 #define rfbEncodingSolMonoZip            0xFFFF0008
 #define rfbEncodingUltraZip              0xFFFF0009
 
+/* Xvp pseudo-encoding */
+#define rfbEncodingXvp 			 0xFFFFFECB
+
 /*
  * Special encoding numbers:
  *   0xFFFFFF00 .. 0xFFFFFF0F -- encoding-specific compression levels;
@@ -1061,6 +1066,44 @@ typedef struct _rfbTextChatMsg {
 #define rfbTextChatFinished 0xFFFFFFFD  
 
 
+/*-----------------------------------------------------------------------------
+ * Xvp Message
+ * Bidirectional message
+ * A server which supports the xvp extension declares this by sending a message
+ * with an Xvp_INIT xvp-message-code when it receives a request from the client
+ * to use the xvp Pseudo-encoding. The server must specify in this message the
+ * highest xvp-extension-version it supports: the client may assume that the
+ * server supports all versions from 1 up to this value. The client is then
+ * free to use any supported version. Currently, only version 1 is defined.
+ *
+ * A server which subsequently receives an xvp Client Message requesting an
+ * operation which it is unable to perform, informs the client of this by
+ * sending a message with an Xvp_FAIL xvp-message-code, and the same
+ * xvp-extension-version as included in the client's operation request.
+ *
+ * A client supporting the xvp extension sends this to request that the server
+ * initiate a clean shutdown, clean reboot or abrupt reset of the system whose
+ * framebuffer the client is displaying.
+ */
+
+
+typedef struct {
+    uint8_t type;			/* always rfbXvp */
+	uint8_t pad;
+	uint8_t version;	/* xvp extension version */
+	uint8_t code;      	/* xvp message code */
+} rfbXvpMsg;
+
+#define sz_rfbXvpMsg (4)
+
+/* server message codes */
+#define rfbXvp_Fail 0
+#define rfbXvp_Init 1
+/* client message codes */
+#define rfbXvp_Shutdown 2
+#define rfbXvp_Reboot 3
+#define rfbXvp_Reset 4
+
 
 /*-----------------------------------------------------------------------------
  * Modif sf@2002
@@ -1115,6 +1158,7 @@ typedef union {
 	rfbPalmVNCReSizeFrameBufferMsg prsfb; 
 	rfbFileTransferMsg ft;
 	rfbTextChatMsg tc;
+        rfbXvpMsg xvp;
 } rfbServerToClientMsg;
 
 
@@ -1350,6 +1394,7 @@ typedef struct _rfbSetSWMsg {
 #define sz_rfbSetSWMsg 6
 
 
+
 /*-----------------------------------------------------------------------------
  * Union of all client->server messages.
  */
@@ -1369,6 +1414,7 @@ typedef union {
 	rfbFileTransferMsg ft;
 	rfbSetSWMsg sw;
 	rfbTextChatMsg tc;
+        rfbXvpMsg xvp;
 } rfbClientToServerMsg;
 
 /*