refactor: 将 DTLS 本地依赖迁移到 libs 目录

libs/dtls/src/extension/extension_server_name.rs

@@ -0,0 +1,56 @@
+#[cfg(test)]
+mod extension_server_name_test;
+
+use std::io::{Read, Write};
+
+use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
+
+use super::*;
+
+const EXTENSION_SERVER_NAME_TYPE_DNSHOST_NAME: u8 = 0;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ExtensionServerName {
+    pub(crate) server_name: String,
+}
+
+impl ExtensionServerName {
+    pub fn extension_value(&self) -> ExtensionValue {
+        ExtensionValue::ServerName
+    }
+
+    pub fn size(&self) -> usize {
+        //TODO: check how to do cryptobyte?
+        2 + 2 + 1 + 2 + self.server_name.len()
+    }
+
+    pub fn marshal<W: Write>(&self, writer: &mut W) -> Result<()> {
+        //TODO: check how to do cryptobyte?
+        writer.write_u16::<BigEndian>(2 + 1 + 2 + self.server_name.len() as u16)?;
+        writer.write_u16::<BigEndian>(1 + 2 + self.server_name.len() as u16)?;
+        writer.write_u8(EXTENSION_SERVER_NAME_TYPE_DNSHOST_NAME)?;
+        writer.write_u16::<BigEndian>(self.server_name.len() as u16)?;
+        writer.write_all(self.server_name.as_bytes())?;
+
+        Ok(writer.flush()?)
+    }
+
+    pub fn unmarshal<R: Read>(reader: &mut R) -> Result<Self> {
+        //TODO: check how to do cryptobyte?
+        let _ = reader.read_u16::<BigEndian>()? as usize;
+        let _ = reader.read_u16::<BigEndian>()? as usize;
+
+        let name_type = reader.read_u8()?;
+        if name_type != EXTENSION_SERVER_NAME_TYPE_DNSHOST_NAME {
+            return Err(Error::ErrInvalidSniFormat);
+        }
+
+        let buf_len = reader.read_u16::<BigEndian>()? as usize;
+        let mut buf: Vec<u8> = vec![0u8; buf_len];
+        reader.read_exact(&mut buf)?;
+
+        let server_name = String::from_utf8(buf)?;
+
+        Ok(ExtensionServerName { server_name })
+    }
+}