Add reliable stream retransmission

src/protocol.rs

@@ -38,12 +38,14 @@ pub fn is_implicit_session_name(name: &str) -> bool {
 }
 
 pub const MAGIC: &[u8; 4] = b"DOSH";
+// v4: added reliable stream offsets/acks to `StreamData` and
+// `StreamWindowAdjust`.
 // v3: added `ForwardingKind::Agent` (SSH-agent forwarding). The new variant rides
 // inside `NativeUserAuth.requested_forwardings`, so a pre-agent peer would fail to
 // deserialize it; bumping the wire version makes such a peer answer with a clear
 // version-mismatch reject instead. Existing variants' bincode discriminants are
 // unchanged, so the bump is purely a compatibility gate.
-pub const VERSION: u8 = 3;
+pub const VERSION: u8 = 4;
 pub const HEADER_LEN: usize = 58;
 
 /// Stable, user-facing reason string the server puts in an `AttachReject` when a
@@ -416,12 +418,14 @@ pub struct StreamOpenReject {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct StreamData {
     pub stream_id: u64,
+    pub offset: u64,
     pub bytes: Vec<u8>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct StreamWindowAdjust {
     pub stream_id: u64,
+    pub received_offset: u64,
     pub bytes: u32,
 }