[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, 1 insertions, 1 deletions

diff --git a/src/protocol/http.rs b/src/protocol/http.rs
index d05c59e..d1eaeeb 100644
--- a/src/protocol/http.rs
+++ b/src/protocol/http.rs
@@ -1,7 +1,7 @@
 use crate::protocol::codec::Decode;
 use nom::IResult;
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct HTTPMessage {
     // TODO
 }