vnc: add support for extended desktop resize

The extended desktop resize encoding adds support for (a) clients
sending resize requests to the server, and (b) multihead support.

This patch implements (a).  All resize requests are rejected by qemu.
Qemu can't resize the framebuffer on its own, this is in the hands of
the guest, so all qemu can do is forward the request to the guest.
Should the guest actually resize the framebuffer we can notify the vnc
client later with a separate message.

This requires support in the display device.  Works with virtio-gpu.

https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst#extendeddesktopsize-pseudo-encoding

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20210112134120.2031837-4-kraxel@redhat.com

1 files changed, 2 insertions, 0 deletions

diff --git a/ui/vnc.h b/ui/vnc.h
index 5feeef9df0..116463d5f0 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -444,6 +444,7 @@ enum {
 
 enum VncFeatures {
     VNC_FEATURE_RESIZE,
+    VNC_FEATURE_RESIZE_EXT,
     VNC_FEATURE_HEXTILE,
     VNC_FEATURE_POINTER_TYPE_CHANGE,
     VNC_FEATURE_WMVI,
@@ -459,6 +460,7 @@ enum VncFeatures {
 };
 
 #define VNC_FEATURE_RESIZE_MASK              (1 << VNC_FEATURE_RESIZE)
+#define VNC_FEATURE_RESIZE_EXT_MASK          (1 << VNC_FEATURE_RESIZE_EXT)
 #define VNC_FEATURE_HEXTILE_MASK             (1 << VNC_FEATURE_HEXTILE)
 #define VNC_FEATURE_POINTER_TYPE_CHANGE_MASK (1 << VNC_FEATURE_POINTER_TYPE_CHANGE)
 #define VNC_FEATURE_WMVI_MASK                (1 << VNC_FEATURE_WMVI)