big changes

common/src/tlseng/tls_record.rs

@@ -0,0 +1,41 @@
+use bytes::{BufMut, Bytes, BytesMut};
+
+use crate::tlseng::types::{ContentType, ProtocolVersion};
+
+/// The TLS Record Layer structure.
+/// This is the outer envelope that wraps all TLS messages sent over the wire.
+#[derive(Debug)]
+pub struct TlsRecord {
+    /// The type of data contained (Handshake, ApplicationData, etc.)
+    pub content_type: ContentType,
+    /// The record layer version (usually 0x0301 for legacy support)
+    pub version: ProtocolVersion,
+
+    pub len: u16,
+    /// The actual data being transported (e.g., a serialized ClientHello)
+    pub payload: Bytes,
+}
+
+impl TlsRecord {
+    pub fn new(content_type: ContentType, version: ProtocolVersion, payload: Bytes) -> Self {
+        Self {
+            content_type,
+            version,
+            len: payload.len() as u16,
+            payload,
+        }
+    }
+
+    /// Serializes the Record Layer header and payload.
+    /// Wire Format: [Type (1)] [Version (2)] [Length (2)] [Payload (N)]
+    pub fn serialize(&self) -> Bytes {
+        let mut buf = BytesMut::with_capacity(5 + self.payload.len());
+
+        buf.put_u8(self.content_type as u8);
+        buf.put_u16(self.version as u16);
+        buf.put_u16(self.payload.len() as u16);
+        buf.put_slice(&self.payload);
+
+        buf.freeze()
+    }
+}