支持tap网卡,优化tun网卡配置

switch/packet/src/ethernet/packet.rs

@@ -0,0 +1,78 @@
+use std::fmt;
+use crate::error::*;
+use crate::ethernet::protocol::Protocol;
+
+/// 以太网帧协议
+/// https://www.ietf.org/rfc/rfc894.txt
+/*
+   0                      6                      12    14 (字节)
+  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  |        目的地址         |         源地址         | 类型 |
+ */
+pub struct EthernetPacket<B> {
+    pub buffer: B,
+}
+
+impl<B: AsRef<[u8]>> EthernetPacket<B> {
+    pub fn unchecked(buffer: B) -> EthernetPacket<B> {
+        EthernetPacket { buffer }
+    }
+
+    pub fn new(buffer: B) -> Result<EthernetPacket<B>> {
+        let packet = EthernetPacket::unchecked(buffer);
+        //头部固定14位
+        if packet.buffer.as_ref().len() < 14 {
+            Err(Error::SmallBuffer)?
+        }
+
+        Ok(packet)
+    }
+}
+
+impl<B: AsRef<[u8]>> EthernetPacket<B> {
+    /// 目的MAC地址
+    pub fn destination(&self) -> &[u8] {
+        &self.buffer.as_ref()[0..6]
+    }
+    /// 源MAC地址
+    pub fn source(&self) -> &[u8] {
+        &self.buffer.as_ref()[6..12]
+    }
+    /// 3层协议
+    pub fn protocol(&self) -> Protocol {
+        u16::from_be_bytes(self.buffer.as_ref()[12..14].try_into().unwrap()).into()
+    }
+    /// 载荷
+    pub fn payload(&self) -> &[u8] {
+        &self.buffer.as_ref()[14..]
+    }
+}
+
+impl<B: AsRef<[u8]> + AsMut<[u8]>> EthernetPacket<B> {
+    pub fn set_destination(&mut self, value: &[u8]) {
+        self.buffer.as_mut()[0..6].copy_from_slice(value);
+    }
+
+    pub fn set_source(&mut self, value: &[u8]) {
+        self.buffer.as_mut()[6..12].copy_from_slice(value);
+    }
+
+    pub fn set_protocol(&mut self, value: Protocol) {
+        let p: u16 = value.into();
+        self.buffer.as_mut()[12..14].copy_from_slice(&p.to_be_bytes())
+    }
+    pub fn payload_mut(&mut self) -> &mut [u8] {
+        &mut self.buffer.as_mut()[14..]
+    }
+}
+
+impl<B: AsRef<[u8]>> fmt::Debug for EthernetPacket<B> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("EthernetPacket")
+            .field("destination", &self.destination())
+            .field("source", &self.source())
+            .field("protocol", &self.protocol())
+            .field("payload", &self.payload())
+            .finish()
+    }
+}