[optimize] Packet Decode

1. Add a macro to obtain Packet’s encapsulation information (the returned data is an immutable reference to Packet)
    * get_innermost_special_encapsulation!()
    * get_outermost_special_encapsulation!()

    Example: let icmp_encapsulation : Option<&Encapsulation> = get_innermost_special_encapsulation!(&Packet, ICMP);
    Example: let l4_encapsulation   : Option<&Encapsulation> = get_innermost_special_encapsulation!(&Packet, TCP | UDP);

2. Clean up the Clone/Copy Trait of PacketDecode to avoid memory copies caused by improper use by users.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/protocol/mpls.rs b/src/protocol/mpls.rs
index add686d..2f441f9 100644
--- a/src/protocol/mpls.rs
+++ b/src/protocol/mpls.rs
@@ -9,7 +9,7 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct MPLSHeader {
     pub label: u32,
     pub experimental: u8,
@@ -17,8 +17,8 @@ pub struct MPLSHeader {
     pub ttl: u8,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
 // Ethernet pseudowire (PW) https://tools.ietf.org/html/rfc4448#section-3.1
+#[derive(Debug, PartialEq)]
 pub struct PWEthHeader {
     pub control_word: u32,
 }