[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.

27 files changed, 194 insertions, 246 deletions

diff --git a/src/event/event.rs b/src/event/event.rs
index 830bdda..476ddce 100644
--- a/src/event/event.rs
+++ b/src/event/event.rs
@@ -1,4 +1,4 @@
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum Event {
     L2Event,
     L3Event,
diff --git a/src/main.rs b/src/main.rs
index 38c35e0..20ec270 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,6 +5,7 @@ use stellar_rs::event::event::Event;
 use stellar_rs::event::manager::EventHandle;
 use stellar_rs::event::manager::EventManager;
 use stellar_rs::event::manager::EventQueue;
+use stellar_rs::get_innermost_special_encapsulation;
 use stellar_rs::packet::capture::PacketCapture;
 use stellar_rs::packet::packet::Encapsulation;
 use stellar_rs::packet::packet::Packet;
@@ -141,7 +142,7 @@ fn handle_one_packet(mut packet: Packet, thread_ctx: &mut ThreadContext) {
         }
     }
 
-    match packet.get_inner_most_tuple() {
+    match get_innermost_special_encapsulation!(packet, TCP | UDP) {
         Some(_) => {
             let flow_id = packet.get_flow_id().unwrap();
             let session = session_mgr.update(flow_id);
diff --git a/src/packet/packet.rs b/src/packet/packet.rs
index b0c7bc5..6a81c4d 100644
--- a/src/packet/packet.rs
+++ b/src/packet/packet.rs
@@ -1,3 +1,5 @@
+use crate::get_innermost_special_encapsulation;
+use crate::get_outermost_special_encapsulation;
 use crate::packet::status::PacketStatus;
 use crate::protocol::codec::Decode;
 use crate::protocol::ethernet::EthHeader;
@@ -24,7 +26,7 @@ use crate::protocol::udp::UDPHeader;
 use crate::protocol::vlan::VLANHeader;
 use nom::Err::Incomplete;
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Debug, PartialEq)]
 pub enum Encapsulation<'a> {
     ETH(EthHeader, &'a [u8]),
     VLAN(VLANHeader, &'a [u8]),
@@ -56,6 +58,36 @@ pub struct Packet<'a> {
     pub encapsulation: Vec<Encapsulation<'a>>,
 }
 
+// return Option<&Encapsulation>
+#[macro_export]
+macro_rules! get_outermost_special_encapsulation {
+    ($packet:expr, $($layer_type:ident)|+ $(|)?) => {
+        $packet
+            .encapsulation
+            .iter()
+            .find(|&encap| {
+                $(matches!(encap, Encapsulation::$layer_type(..)) ||)+
+                false
+            })
+            .map(|layer| layer)
+    };
+}
+
+// return Option<&Encapsulation>
+#[macro_export]
+macro_rules! get_innermost_special_encapsulation {
+    ($packet:expr, $($layer_type:ident)|+ $(|)?) => {
+        $packet
+            .encapsulation
+            .iter()
+            .rfind(|&encap| {
+                $(matches!(encap, Encapsulation::$layer_type(..)) ||)+
+                false
+            })
+            .map(|layer| layer)
+    };
+}
+
 impl Packet<'_> {
     pub fn new(data: &[u8], len: u32) -> Packet {
         Packet {
@@ -73,155 +105,67 @@ impl Packet<'_> {
         }
     }
 
-    pub fn get_outer_most_l3_layer(&self) -> Option<Encapsulation> {
-        let num = self.encapsulation.len();
-        for i in 0..num {
-            match self.encapsulation[i] {
-                Encapsulation::IPv4(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                Encapsulation::IPv6(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                _ => continue,
+    pub fn get_outermost_address(&self) -> Option<(String, String)> {
+        match get_outermost_special_encapsulation!(self, IPv4 | IPv6) {
+            Some(&Encapsulation::IPv4(ref header, _)) => {
+                return Some((
+                    header.source_address.to_string(),
+                    header.dest_address.to_string(),
+                ));
             }
-        }
-
-        None
-    }
-
-    pub fn get_inner_most_l3_layer(&self) -> Option<Encapsulation> {
-        let num = self.encapsulation.len();
-        for i in (0..num).rev() {
-            match self.encapsulation[i] {
-                Encapsulation::IPv4(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                Encapsulation::IPv6(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                _ => continue,
+            Some(&Encapsulation::IPv6(ref header, _)) => {
+                return Some((
+                    header.source_address.to_string(),
+                    header.dest_address.to_string(),
+                ));
             }
+            _ => return None,
         }
-
-        None
     }
 
-    pub fn get_outer_most_l4_layer(&self) -> Option<Encapsulation> {
-        let num = self.encapsulation.len();
-        for i in 0..num {
-            match self.encapsulation[i] {
-                Encapsulation::TCP(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                Encapsulation::UDP(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                _ => continue,
+    pub fn get_innermost_address(&self) -> Option<(String, String)> {
+        match get_innermost_special_encapsulation!(self, IPv4 | IPv6) {
+            Some(&Encapsulation::IPv4(ref header, _)) => {
+                return Some((
+                    header.source_address.to_string(),
+                    header.dest_address.to_string(),
+                ));
             }
-        }
-
-        None
-    }
-
-    pub fn get_inner_most_l4_layer(&self) -> Option<Encapsulation> {
-        let num = self.encapsulation.len();
-        for i in (0..num).rev() {
-            match self.encapsulation[i] {
-                Encapsulation::TCP(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                Encapsulation::UDP(_, _) => {
-                    return Some(self.encapsulation[i].clone());
-                }
-                _ => continue,
+            Some(&Encapsulation::IPv6(ref header, _)) => {
+                return Some((
+                    header.source_address.to_string(),
+                    header.dest_address.to_string(),
+                ));
             }
+            _ => return None,
         }
-
-        None
     }
 
-    pub fn get_outer_most_address(&self) -> Option<(String, String)> {
-        let num = self.encapsulation.len();
-        for i in 0..num {
-            match self.encapsulation[i] {
-                Encapsulation::IPv4(ref header, _) => {
-                    return Some((
-                        header.source_address.to_string(),
-                        header.dest_address.to_string(),
-                    ));
-                }
-                Encapsulation::IPv6(ref header, _) => {
-                    return Some((
-                        header.source_address.to_string(),
-                        header.dest_address.to_string(),
-                    ));
-                }
-                _ => continue,
+    pub fn get_outermost_port(&self) -> Option<(u16, u16)> {
+        match get_outermost_special_encapsulation!(self, TCP | UDP) {
+            Some(&Encapsulation::TCP(ref header, _)) => {
+                return Some((header.source_port, header.dest_port));
             }
-        }
-
-        None
-    }
-
-    pub fn get_inner_most_address(&self) -> Option<(String, String)> {
-        let num = self.encapsulation.len();
-        for i in (0..num).rev() {
-            match self.encapsulation[i] {
-                Encapsulation::IPv4(ref header, _) => {
-                    return Some((
-                        header.source_address.to_string(),
-                        header.dest_address.to_string(),
-                    ));
-                }
-                Encapsulation::IPv6(ref header, _) => {
-                    return Some((
-                        header.source_address.to_string(),
-                        header.dest_address.to_string(),
-                    ));
-                }
-                _ => continue,
+            Some(&Encapsulation::UDP(ref header, _)) => {
+                return Some((header.source_port, header.dest_port));
             }
+            _ => return None,
         }
-
-        None
     }
 
-    pub fn get_outer_most_port(&self) -> Option<(u16, u16)> {
-        let num = self.encapsulation.len();
-        for i in 0..num {
-            match self.encapsulation[i] {
-                Encapsulation::TCP(ref header, _) => {
-                    return Some((header.source_port, header.dest_port));
-                }
-                Encapsulation::UDP(ref header, _) => {
-                    return Some((header.source_port, header.dest_port));
-                }
-                _ => continue,
+    pub fn get_innermost_port(&self) -> Option<(u16, u16)> {
+        match get_innermost_special_encapsulation!(self, TCP | UDP) {
+            Some(&Encapsulation::TCP(ref header, _)) => {
+                return Some((header.source_port, header.dest_port));
             }
-        }
-
-        None
-    }
-
-    pub fn get_inner_most_port(&self) -> Option<(u16, u16)> {
-        let num = self.encapsulation.len();
-        for i in (0..num).rev() {
-            match self.encapsulation[i] {
-                Encapsulation::TCP(ref header, _) => {
-                    return Some((header.source_port, header.dest_port));
-                }
-                Encapsulation::UDP(ref header, _) => {
-                    return Some((header.source_port, header.dest_port));
-                }
-                _ => continue,
+            Some(&Encapsulation::UDP(ref header, _)) => {
+                return Some((header.source_port, header.dest_port));
             }
+            _ => return None,
         }
-
-        None
     }
 
-    pub fn get_outer_most_tuple(&self) -> Option<(String, u16, String, u16)> {
+    pub fn get_outermost_tuple(&self) -> Option<(String, u16, String, u16)> {
         let num = self.encapsulation.len();
         if num < 2 {
             return None;
@@ -273,7 +217,7 @@ impl Packet<'_> {
         None
     }
 
-    pub fn get_inner_most_tuple(&self) -> Option<(String, u16, String, u16)> {
+    pub fn get_innermost_tuple(&self) -> Option<(String, u16, String, u16)> {
         let num = self.encapsulation.len();
         if num < 2 {
             return None;
@@ -818,6 +762,31 @@ mod tests {
     use std::net::Ipv6Addr;
 
     #[test]
+    fn test_encapsulated_immutable_references() {
+        let mut packet = Packet::new(b"0", 1 as u32);
+        let udp_hdr = UDPHeader {
+            source_port: 9995,
+            dest_port: 9996,
+            length: 147,
+            checksum: 0x57d4,
+        };
+
+        let udp_payload = [0x01, 0x02, 0x03];
+        packet
+            .encapsulation
+            .push(Encapsulation::UDP(udp_hdr, &udp_payload));
+
+        match get_innermost_special_encapsulation!(packet, UDP) {
+            Some(&Encapsulation::UDP(ref header, payload)) => {
+                assert_eq!(header.source_port, 9995);
+                assert_eq!(header.dest_port, 9996);
+                assert_eq!(payload, &udp_payload);
+            }
+            _ => assert!(false),
+        }
+    }
+
+    #[test]
     fn test_packet_api() {
         let mut packet = Packet::new(b"0", 1 as u32);
         let ipv4_hdr = IPv4Header {
@@ -877,34 +846,30 @@ mod tests {
 
         packet
             .encapsulation
-            .push(Encapsulation::IPv4(ipv4_hdr.clone(), b"1"));
+            .push(Encapsulation::IPv4(ipv4_hdr, b"1"));
+        packet.encapsulation.push(Encapsulation::TCP(tcp_hdr, b"2"));
         packet
             .encapsulation
-            .push(Encapsulation::TCP(tcp_hdr.clone(), b"2"));
-        packet
-            .encapsulation
-            .push(Encapsulation::IPv6(ipv6_hdr.clone(), b"3"));
-        packet
-            .encapsulation
-            .push(Encapsulation::UDP(udp_hdr.clone(), b"4"));
+            .push(Encapsulation::IPv6(ipv6_hdr, b"3"));
+        packet.encapsulation.push(Encapsulation::UDP(udp_hdr, b"4"));
 
         assert_eq!(
-            packet.get_outer_most_address(),
+            packet.get_outermost_address(),
             Some(("192.168.0.101".to_string(), "121.14.154.93".to_string()))
         );
         assert_eq!(
-            packet.get_inner_most_address(),
+            packet.get_innermost_address(),
             Some((
                 "2409:8034:4025::50:a31".to_string(),
                 "2409:8034:4040:5301::204".to_string()
             ))
         );
 
-        assert_eq!(packet.get_outer_most_port(), Some((50081, 443)));
-        assert_eq!(packet.get_inner_most_port(), Some((9993, 9994)));
+        assert_eq!(packet.get_outermost_port(), Some((50081, 443)));
+        assert_eq!(packet.get_innermost_port(), Some((9993, 9994)));
 
         assert_eq!(
-            packet.get_outer_most_tuple(),
+            packet.get_outermost_tuple(),
             Some((
                 "192.168.0.101".to_string(),
                 50081,
@@ -913,7 +878,7 @@ mod tests {
             ))
         );
         assert_eq!(
-            packet.get_inner_most_tuple(),
+            packet.get_innermost_tuple(),
             Some((
                 "2409:8034:4025::50:a31".to_string(),
                 9993,
@@ -922,23 +887,6 @@ mod tests {
             ))
         );
 
-        assert_eq!(
-            packet.get_outer_most_l3_layer(),
-            Some(Encapsulation::IPv4(ipv4_hdr, b"1"))
-        );
-        assert_eq!(
-            packet.get_inner_most_l3_layer(),
-            Some(Encapsulation::IPv6(ipv6_hdr, b"3"))
-        );
-        assert_eq!(
-            packet.get_outer_most_l4_layer(),
-            Some(Encapsulation::TCP(tcp_hdr, b"2"))
-        );
-        assert_eq!(
-            packet.get_inner_most_l4_layer(),
-            Some(Encapsulation::UDP(udp_hdr, b"4"))
-        );
-
         assert_eq!(packet.get_flow_id(), Some("192.168.0.101->121.14.154.93;TCP->TCP;50081->443;2409:8034:4025::50:a31->2409:8034:4040:5301::204;UDP->UDP;9993->9994;".to_string()));
     }
 
diff --git a/src/packet/status.rs b/src/packet/status.rs
index 25585c0..cc536de 100644
--- a/src/packet/status.rs
+++ b/src/packet/status.rs
@@ -2,7 +2,7 @@ use crate::protocol::ethernet::EthType;
 use crate::protocol::ip::IPProtocol;
 use std::collections::HashMap;
 
-#[derive(Debug, Clone, Copy, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum PacketStatus {
     Normal,
 
diff --git a/src/plugin/example.rs b/src/plugin/example.rs
index 7a4d4ec..a7afb5b 100644
--- a/src/plugin/example.rs
+++ b/src/plugin/example.rs
@@ -53,7 +53,7 @@ impl EventHandle for ExamplePulgin {
         match event {
             Event::TCPOpeningEvent => {
                 println!("{} handle TCPOpeningEvent: {:?}", self.plugin_name, session);
-                let (src_port, dst_port) = packet.unwrap().get_inner_most_port().unwrap();
+                let (src_port, dst_port) = packet.unwrap().get_innermost_port().unwrap();
                 if src_port == 80 || dst_port == 80 {
                     println!("{} add HTTPRequestEvent", self.plugin_name);
                     queue.add(Event::HTTPRequestEvent, Some(session));
diff --git a/src/protocol/codec.rs b/src/protocol/codec.rs
index 7bf2243..575e49d 100644
--- a/src/protocol/codec.rs
+++ b/src/protocol/codec.rs
@@ -2,7 +2,7 @@ use nom::IResult;
 use std::fmt::Debug;
 
 pub trait Decode {
-    type Iterm: Debug;
+    type Iterm: Debug + PartialEq;
     fn decode(input: &[u8]) -> IResult<&[u8], Self::Iterm>;
 }
 
diff --git a/src/protocol/dns.rs b/src/protocol/dns.rs
index 0f62b49..c2d2411 100644
--- a/src/protocol/dns.rs
+++ b/src/protocol/dns.rs
@@ -220,7 +220,7 @@ use std::str;
  * DNS Header
  ******************************************************************************/
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum DNSHeaderQR {
     Query = 0,
     Response = 1,
@@ -238,7 +238,7 @@ impl DNSHeaderQR {
 }
 
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-5
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum DNSHeaderOpcode {
     Query,
     IQuery,
@@ -265,7 +265,7 @@ impl DNSHeaderOpcode {
 }
 
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum DNSHeaderRcode {
     NoError,   // No Error
     FormErr,   // Format Error
@@ -319,7 +319,7 @@ impl DNSHeaderRcode {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSHeader {
     pub id: u16,
     pub qr: DNSHeaderQR,
@@ -424,7 +424,7 @@ impl DNSHeader {
  ******************************************************************************/
 
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-4
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum DNSQtype {
     A,          // a host address
     NS,         // an authoritative name server
@@ -620,7 +620,7 @@ impl DNSQtype {
 }
 
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-2
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum DNSQclass {
     Internet,
     Unassigned,
@@ -645,7 +645,7 @@ impl DNSQclass {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSQuestionSection {
     pub qname: String,
     pub qtype: DNSQtype,
@@ -679,7 +679,7 @@ impl DNSQuestionSection {
  * DNS Resource Record Section
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSResourceRecordHeader {
     pub qname: String,
     pub rr_type: DNSQtype,
@@ -715,7 +715,7 @@ impl DNSResourceRecordHeader {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum DNSResourceRecordData {
     A {
         address: String,
@@ -884,7 +884,7 @@ impl DNSResourceRecordData {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSResourceRecordSection {
     pub hdr: DNSResourceRecordHeader,
     pub data: DNSResourceRecordData,
@@ -915,7 +915,7 @@ impl DNSResourceRecordSection {
  ******************************************************************************/
 
 // https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-10
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 enum DNSLabelType {
     Normal(usize),  // Normal label lower 6 bits is the length of the label
     Pointer(usize), // Compressed label the lower 6 bits and the 8 bits from next octet form a pointer to the compression target
@@ -965,7 +965,7 @@ impl DNSLabelType {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSLabelTable {
     pub labels: Vec<((usize, usize), String)>,
 }
@@ -1028,7 +1028,7 @@ impl DNSLabelTable {
  * DNS Message
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct DNSMessage {
     pub header: DNSHeader,
     labels: DNSLabelTable,
diff --git a/src/protocol/ethernet.rs b/src/protocol/ethernet.rs
index f8e39f8..375be59 100644
--- a/src/protocol/ethernet.rs
+++ b/src/protocol/ethernet.rs
@@ -6,10 +6,7 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub struct MacAddress(pub [u8; 6]);
-
-#[derive(Clone, Copy, Hash, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum EthType {
     LANMIN,         // 802.3 Min data length
     LANMAX,         // 802.3 Max data length
@@ -61,7 +58,10 @@ pub enum EthType {
     Other(u16),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
+pub struct MacAddress(pub [u8; 6]);
+
+#[derive(Debug, PartialEq)]
 pub struct EthHeader {
     pub source_mac: MacAddress,
     pub dest_mac: MacAddress,
diff --git a/src/protocol/grev0.rs b/src/protocol/grev0.rs
index 88a43f1..784613e 100644
--- a/src/protocol/grev0.rs
+++ b/src/protocol/grev0.rs
@@ -40,7 +40,7 @@ use nom::IResult;
  * https://datatracker.ietf.org/doc/html/rfc2890
  */
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct SourceRouteEntry {
     pub address_family: u16,
     pub sre_offset: u8,
@@ -48,7 +48,7 @@ pub struct SourceRouteEntry {
     pub sre_routing: Vec<u8>,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct GREv0Header {
     pub flag_checksum: bool,
     pub flag_routing: bool,
diff --git a/src/protocol/grev1.rs b/src/protocol/grev1.rs
index ed2d2f2..e444f5b 100644
--- a/src/protocol/grev1.rs
+++ b/src/protocol/grev1.rs
@@ -28,7 +28,7 @@ use nom::IResult;
  * https://datatracker.ietf.org/doc/html/rfc2637
  */
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct GREv1Header {
     pub flag_checksum: bool,
     pub flag_routing: bool,
diff --git a/src/protocol/gtpv1.rs b/src/protocol/gtpv1.rs
index 8a7fc4d..c3d9896 100644
--- a/src/protocol/gtpv1.rs
+++ b/src/protocol/gtpv1.rs
@@ -10,21 +10,21 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct GTPv1Option {
     pub sequence_number: u16, // 16bit
     pub npdu_number: u8,      // 8bit
     pub next_header_type: u8, // 8bit
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct GTPv1ExtensionHeader {
     pub length: u8, // 8bit (单位4字节，包括长度/内容/下一扩展消息头字段)
     pub contents: Vec<u8>,
     pub next_header_type: u8, // 8bit
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct GTPv1Header {
     pub version: u8,               // 3bit 1: GTPv1
     pub protocol_type: u8,         // 1bit
@@ -129,14 +129,18 @@ impl Decode for GTPv1Header {
         }
 
         let mut extensions = Vec::new();
-        if options.is_some() {
-            let mut next_header = options.clone().unwrap().next_header_type;
-            while next_header != 0 {
-                let (left, extension) = extension_decode(remain)?;
-                remain = left;
-                next_header = extension.next_header_type;
-                extensions.push(extension);
+        let ref_options = &options;
+        match ref_options {
+            Some(ref _options) => {
+                let mut next_header = _options.next_header_type;
+                while next_header != 0 {
+                    let (left, extension) = extension_decode(remain)?;
+                    remain = left;
+                    next_header = extension.next_header_type;
+                    extensions.push(extension);
+                }
             }
+            None => (),
         }
 
         Ok((
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
 }
diff --git a/src/protocol/icmp.rs b/src/protocol/icmp.rs
index 99d0f2d..2c48962 100644
--- a/src/protocol/icmp.rs
+++ b/src/protocol/icmp.rs
@@ -6,7 +6,7 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum ICMPType {
     EchoReply,
     DestinationUnreachable,
@@ -27,7 +27,7 @@ pub enum ICMPType {
     Other(u8),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct ICMPHeader {
     pub icmp_type: ICMPType,
     pub icmp_code: u8,
diff --git a/src/protocol/icmpv6.rs b/src/protocol/icmpv6.rs
index 9bd58d2..d0c5e1c 100644
--- a/src/protocol/icmpv6.rs
+++ b/src/protocol/icmpv6.rs
@@ -6,7 +6,7 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum ICMPv6Type {
     DestinationUnreachable,
     PacketTooBig,
@@ -48,7 +48,7 @@ pub enum ICMPv6Type {
     Other(u8),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct ICMPv6Header {
     pub icmp_type: ICMPv6Type,
     pub icmp_code: u8,
diff --git a/src/protocol/ipv4.rs b/src/protocol/ipv4.rs
index 7606b1e..2297196 100644
--- a/src/protocol/ipv4.rs
+++ b/src/protocol/ipv4.rs
@@ -31,7 +31,7 @@ use std::net::Ipv4Addr;
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct IPv4Header {
     pub version: u8, // 4 bit
     pub ihl: u8,     // 4 bit
diff --git a/src/protocol/ipv6.rs b/src/protocol/ipv6.rs
index 11666d4..f9e4321 100644
--- a/src/protocol/ipv6.rs
+++ b/src/protocol/ipv6.rs
@@ -59,14 +59,14 @@ use std::net::Ipv6Addr;
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct IPv6Extension {
     pub next_header: IPProtocol,
     pub ext_length: u8, // Extension total Length
     pub data: Vec<u8>,  // Extension data length (ext_length - 2)
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct IPv6Header {
     pub version: u8,     // 4 bit
     pub dsc: u8,         // Differentiated Services Codepoint: 6 bit
diff --git a/src/protocol/l2tp.rs b/src/protocol/l2tp.rs
index 445062f..5474b23 100644
--- a/src/protocol/l2tp.rs
+++ b/src/protocol/l2tp.rs
@@ -42,7 +42,7 @@ use nom::IResult;
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum L2TPAVPType {
     Message,
     Result,
@@ -137,13 +137,13 @@ pub enum L2TPAVPType {
     Other(u16),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum L2TPType {
     Data,
     Control,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct L2TPAVPHeader {
     pub mandatory: bool,
     pub hidden: bool,
@@ -154,7 +154,7 @@ pub struct L2TPAVPHeader {
     pub attribute_value: Vec<u8>,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct L2TPHeader {
     pub flags: u16,
     pub flag_type: L2TPType,
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,
 }
diff --git a/src/protocol/ppp.rs b/src/protocol/ppp.rs
index 1c08ce7..0872915 100644
--- a/src/protocol/ppp.rs
+++ b/src/protocol/ppp.rs
@@ -7,7 +7,7 @@ use nom::IResult;
  ******************************************************************************/
 
 // https://www.iana.org/assignments/ppp-numbers/ppp-numbers.xhtml
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum PPPProtocol {
     PAD,  // Padding Protocol
     IPv4, // Internet Protocol version 4 (IPv4)
@@ -21,7 +21,7 @@ pub enum PPPProtocol {
 }
 
 // https://www.rfc-editor.org/rfc/rfc1661.html
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct PPPHeader {
     pub address: u8,
     pub control: u8,
diff --git a/src/protocol/pppoe.rs b/src/protocol/pppoe.rs
index e63dbb1..7f3e05e 100644
--- a/src/protocol/pppoe.rs
+++ b/src/protocol/pppoe.rs
@@ -25,7 +25,7 @@ use nom::IResult;
  * https://info.support.huawei.com/info-finder/encyclopedia/zh/PPPoE.html
  */
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum PPPoECode {
     SessionData, // Session Data
     PADI,        // Active Discovery Initiation
@@ -36,7 +36,7 @@ pub enum PPPoECode {
     Other(u8),
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum PPPoETagType {
     EndOfList,
     ServiceName,
@@ -51,20 +51,20 @@ pub enum PPPoETagType {
     Other(u16),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct PPPoETag {
     pub tag_type: PPPoETagType,
     pub tag_length: u16,
     pub tag_value: Vec<u8>,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum PPPoEStage {
     Discovery(Vec<PPPoETag>),
     Session(PPPProtocol),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct PPPoEHeader {
     pub version: u8,         // 4 bits
     pub type_: u8,           // 4 bits
@@ -137,10 +137,10 @@ fn pppoe_tags_decode(input: &[u8]) -> IResult<&[u8], Vec<PPPoETag>> {
     let mut remain = input;
     loop {
         let (input, tag) = pppoe_tag_decode(remain)?;
-        let tag_type = tag.tag_type;
+        let is_end_of_list = tag.tag_type == PPPoETagType::EndOfList;
         remain = input;
         tags.push(tag);
-        if remain.is_empty() || tag_type == PPPoETagType::EndOfList {
+        if remain.is_empty() || is_end_of_list {
             break;
         }
     }
diff --git a/src/protocol/pptp.rs b/src/protocol/pptp.rs
index c9e2b40..c254631 100644
--- a/src/protocol/pptp.rs
+++ b/src/protocol/pptp.rs
@@ -29,14 +29,14 @@ use nom::Needed;
 // https://wwwdisc.chimica.unipd.it/luigino.feltre/pubblica/unix/winnt_doc/pppt/understanding_pptp.html
 // https://datatracker.ietf.org/doc/html/rfc2637
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum PPTPMessageType {
     ControlMessage,
     ManagementMessage,
     UnknownMessage(u16),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum PPTPControlMessageType {
     StartControlConnectionRequest,
     StartControlConnectionReply,
@@ -56,7 +56,7 @@ pub enum PPTPControlMessageType {
     Unknown(u16),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct PPTPHeader {
     pub length: u16,
     pub message_type: PPTPMessageType,
diff --git a/src/protocol/tcp.rs b/src/protocol/tcp.rs
index 5ab7dde..09a5690 100644
--- a/src/protocol/tcp.rs
+++ b/src/protocol/tcp.rs
@@ -44,7 +44,7 @@ const TCP_OPTION_SACK_PERMITTED: u8 = 4; // Selective acknowledgements permitted
 const TCP_OPTION_SACK: u8 = 5; // Selective acknowledgment
 const TCP_OPTION_TIMESTAMPS: u8 = 8; // Timestamps
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub enum TCPOption {
     EOL,
     NOP,
@@ -69,7 +69,7 @@ pub enum TCPOption {
     },
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct TCPHeader {
     pub source_port: u16,
     pub dest_port: u16,
@@ -212,12 +212,10 @@ impl TCPHeader {
             match TCPOption::decode(left) {
                 Ok((l, opt)) => {
                     left = l;
+                    let is_eol = opt == TCPOption::EOL;
                     options.push(opt);
 
-                    if left.len() <= 0 {
-                        break;
-                    }
-                    if let TCPOption::EOL = opt {
+                    if left.len() <= 0 || is_eol {
                         break;
                     }
                 }
diff --git a/src/protocol/udp.rs b/src/protocol/udp.rs
index 1d7b43b..8554057 100644
--- a/src/protocol/udp.rs
+++ b/src/protocol/udp.rs
@@ -20,7 +20,7 @@ use nom::IResult;
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  */
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct UDPHeader {
     pub source_port: u16,
     pub dest_port: u16,
diff --git a/src/protocol/vlan.rs b/src/protocol/vlan.rs
index 6a1dbe0..0e9b0c5 100644
--- a/src/protocol/vlan.rs
+++ b/src/protocol/vlan.rs
@@ -9,7 +9,7 @@ use nom::IResult;
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct VLANHeader {
     // A 3 bit number which refers to the IEEE 802.1p class of service and maps to the frame priority level.
     pub priority_code_point: u8,
diff --git a/src/session/manager.rs b/src/session/manager.rs
index 462949f..36bb19e 100644
--- a/src/session/manager.rs
+++ b/src/session/manager.rs
@@ -11,7 +11,6 @@ use std::rc::Rc;
  * Struct
  ******************************************************************************/
 
-#[derive(Debug)]
 pub struct SessionManager {
     sessions: HashMap<String, Rc<RefCell<Session>>>,
 }
@@ -154,7 +153,5 @@ mod tests {
         // Research Session
         assert_eq!(session_mgr.get_session(&session_id).is_none(), true);
         assert_eq!(session_mgr.get_session(&reversed_id).is_none(), true);
-
-        dbg!(session_mgr);
     }
 }
diff --git a/src/session/session.rs b/src/session/session.rs
index e8b2be4..1db4bfd 100644
--- a/src/session/session.rs
+++ b/src/session/session.rs
@@ -7,19 +7,19 @@ use std::collections::HashMap;
 
 const MAX_SESSION_EXPIRE_TIME: i64 = 60;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum SessionDirection {
     C2S,
     S2C,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum SessionProto {
     TCP,
     UDP,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq)]
 pub enum SessionState {
     New,
     Active,
@@ -27,7 +27,7 @@ pub enum SessionState {
     Expired,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug)]
 pub struct SessionMetrics {
     pub send_pkts: u64,
     pub send_bytes: u64,
@@ -35,7 +35,7 @@ pub struct SessionMetrics {
     pub recv_bytes: u64,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Debug)]
 struct SessionTimeStamp {
     ts_start: i64,
     ts_end: i64,
@@ -49,7 +49,7 @@ struct SessionTimeStamp {
  *  - if current packet is iterm of session, require packet lifetime > session lifetime
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug)]
 pub struct Session {
     session_id: String,
     session_proto: SessionProto,
@@ -132,8 +132,8 @@ impl Session {
         self.session_metrics_c2s.recv_bytes += recv_bytes;
     }
 
-    pub fn get_session_c2s_metrics(&self) -> SessionMetrics {
-        self.session_metrics_c2s
+    pub fn get_session_c2s_metrics(&self) -> &SessionMetrics {
+        &self.session_metrics_c2s
     }
 
     pub fn inc_session_s2c_metrics(
@@ -149,8 +149,8 @@ impl Session {
         self.session_metrics_s2c.recv_bytes += recv_bytes;
     }
 
-    pub fn get_session_s2c_metrics(&self) -> SessionMetrics {
-        self.session_metrics_s2c
+    pub fn get_session_s2c_metrics(&self) -> &SessionMetrics {
+        &self.session_metrics_s2c
     }
 
     pub fn update_session_expire_ts(&mut self) {
diff --git a/src/session/tuple.rs b/src/session/tuple.rs
index 9a4dacf..16616cb 100644
--- a/src/session/tuple.rs
+++ b/src/session/tuple.rs
@@ -2,7 +2,7 @@
  * Struct
  ******************************************************************************/
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq)]
 pub struct FiveTuple {
     src_ip: String,
     src_port: u16,