[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.

19 files changed, 68 insertions, 66 deletions

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,