feat(ssh): Add ScpState state machine for SCP file transfer (Phase 8.3 init)

markbase-core/src/ssh_server/channel.rs

@@ -178,6 +178,7 @@ impl ChannelManager {
             exec_process: None,            // Phase 14: 交互式exec
             sftp_input_buffer: Vec::new(), // ⭐⭐⭐⭐⭐ Phase 14.2修复：SFTP packet累积
             scp_input_buffer: Vec::new(),  // ⭐⭐⭐⭐⭐ Phase 14.4修复：SCP packet累积
+            scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
             direct_tcpip: None,
             forwarded_tcpip: None,
         };
@@ -255,6 +256,7 @@ impl ChannelManager {
             exec_process: None,
             sftp_input_buffer: Vec::new(),
             scp_input_buffer: Vec::new(),
+            scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
             direct_tcpip: Some(direct_tcpip),
             forwarded_tcpip: None,
         };
@@ -329,6 +331,7 @@ impl ChannelManager {
             exec_process: None,            // Phase 14: 交互式exec
             sftp_input_buffer: Vec::new(), // ⭐⭐⭐⭐⭐ Phase 14.2修复
             scp_input_buffer: Vec::new(),  // ⭐⭐⭐⭐⭐ Phase 14.4修复
+            scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
             direct_tcpip: None,
             forwarded_tcpip: Some(forwarded_tcpip),
         };
@@ -1945,6 +1948,8 @@ struct Channel {
     sftp_input_buffer: Vec<u8>, // Phase 14.2修复：累积不完整的SFTP packets
     // ⭐⭐⭐⭐⭐ Phase 14.4：SCP packet累积buffer
     scp_input_buffer: Vec<u8>, // Phase 14.4修复：累积不完整的SCP packets
+    // ⭐⭐⭐⭐⭐ Phase 8.3: SCP file transfer state machine
+    scp_state: ScpState,       // Phase 8.3: SCP state tracking
     // Phase 13.3: 端口转发相关字段
     direct_tcpip: Option<DirectTcpipChannel>, // direct-tcpip channel（Remote forwarding）
     forwarded_tcpip: Option<ForwardedTcpipChannel>, // forwarded-tcpip channel（Local forwarding）
@@ -1957,6 +1962,21 @@ enum ChannelState {
     Closed,
 }
 
+/// ⭐⭐⭐⭐⭐ Phase 8.3: SCP file transfer state machine
+/// Reference: OpenSSH scp.c: sink() (destination mode)
+#[derive(Debug, Clone)]
+enum ScpState {
+    Idle,
+    FileCommandReceived {
+        size: u64,
+        filename: String,
+        remaining: u64,
+    },
+    DirectoryCreated {
+        dirname: String,
+    },
+}
+
 /// SSH string读取辅助函数
 fn read_ssh_string<R: std::io::Read>(reader: &mut R) -> Result<String> {
     let length = reader.read_u32::<BigEndian>()?;