Add support for the TS_SYNC_EVENT (#34)

This is used to synchronize the state of the toggle keys
(like caps lock), as well as to reset the server state to
"all keys up."

src/core/client.rs

@@ -102,6 +102,9 @@ impl<S: Read + Write> RdpClient<S> {
             }
             // Raw keyboard input
             RdpEvent::Key(key) => self.global.write_input_event(key.into(), &mut self.mcs),
+            // Input sync
+            RdpEvent::Sync(sync) => self.global.write_input_event(sync.into(), &mut self.mcs),
+
             _ => Err(Error::RdpError(RdpError::new(
                 RdpErrorKind::UnexpectedType,
                 "RDPCLIENT: This event can't be sent",

src/core/event.rs

@@ -169,6 +169,12 @@ pub struct KeyboardEvent {
     pub down: bool,
 }
 
+#[derive(Debug)]
+pub struct InputSyncEvent {
+    /// Indicates which of the toggle keys are active.
+    pub flags: u32,
+}
+
 /// All event handle by RDP protocol implemented by rdp-rs
 #[derive(Debug)]
 pub enum RdpEvent {
@@ -178,4 +184,6 @@ pub enum RdpEvent {
     Pointer(PointerEvent),
     /// Keyboard event
     Key(KeyboardEvent),
+    /// Input sync event
+    Sync(InputSyncEvent),
 }

src/core/global.rs

@@ -1,7 +1,7 @@
 use crate::core::capability;
 use crate::core::capability::{capability_set, Capability};
 use crate::core::event::{
-    BitmapEvent, KeyboardEvent, PointerButton, PointerEvent, PointerWheel, RdpEvent,
+    BitmapEvent, InputSyncEvent, KeyboardEvent, PointerButton, PointerEvent, PointerWheel, RdpEvent,
 };
 use crate::core::gcc::KeyboardLayout;
 use crate::core::mcs;
@@ -601,6 +601,34 @@ pub fn ts_keyboard_event(flags: Option<u16>, key_code: Option<u16>) -> TSInputEv
     }
 }
 
+#[repr(u32)]
+pub enum InputSyncFlags {
+    TsSyncScrollLock = 0x00000001,
+    TsSyncNumLock = 0x00000002,
+    TsSyncCapsLock = 0x00000004,
+    TsSyncKanaLock = 0x00000008,
+}
+
+/// The TS_SYNC_EVENT is used to synchronize the value of the toggle keys
+/// and to reset the server state to "all keys up."
+///
+/// See https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/6c5d0ef9-4653-4d69-9ba9-09ba3acd660f
+pub fn ts_sync_event(toggle_flags: Option<u32>) -> TSInputEvent {
+    TSInputEvent {
+        event_type: InputEventType::InputEventSync,
+        message: component![
+            "pad2Octets" => U16::LE(0),
+            "toggleFlags" => U32::LE(toggle_flags.unwrap_or(0))
+        ],
+    }
+}
+
+impl From<InputSyncEvent> for TSInputEvent {
+    fn from(evt: InputSyncEvent) -> Self {
+        ts_sync_event(Some(evt.flags))
+    }
+}
+
 /// Fast Path update (Not a PDU)
 ///
 /// https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/a1c4caa8-00ed-45bb-a06e-5177473766d3