haprox-rs 0.2.3

/*-
 * haprox-rs - a HaProxy protocol parser.
 * 
 * Copyright 2025 Aleksandr Morozov
 * The scram-rs crate can be redistributed and/or modified
 * under the terms of either of the following licenses:
 *
 *   1. the Mozilla Public License Version 2.0 (the “MPL”) OR
 *                     
 *   2. EUROPEAN UNION PUBLIC LICENCE v. 1.2 EUPL © the European Union 2007, 2016
 */

use std::borrow::Cow;
use std::ffi::CStr;
use std::fmt;
use std::io::{Cursor, Read, Write};
use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
use std::ops::RangeInclusive;
use std::os::unix::ffi::OsStrExt;
use std::os::unix::net;
use std::str::FromStr;

use bitflags::bitflags;
use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};

use crate::{common, map_error, return_error};
use crate::error::{HaProxErr, HaProxRes};

use super::protocol_raw::{self, HEADER_UNIX_ADDR_LEN};

// -----
// The following range of 16 type values is reserved for application-specific
// data and will be never used by the PROXY Protocol. If you need more values
// consider extending the range with a type field in your TLVs.

/// values is reserved for application-specific data and will be never 
/// used by the PROXY Protocol (minimal type)
pub const PP2_TYPE_MIN_CUSTOM: u8 = 0xE0;

/// values is reserved for application-specific data and will be never 
/// used by the PROXY Protocol (max type)
pub const PP2_TYPE_MAX_CUSTOM: u8 = 0xEF;

// ----
// The following range of 8 values is reserved for future use, potentially to
// extend the protocol with multibyte type values.

/// reserved for temporary experimental use by application developers and protocol 
/// designers (min range)
pub const PP2_TYPE_MIN_EXPERIMENT: u8 = 0xF0;

/// reserved for temporary experimental use by application developers and protocol 
/// designers (max range)
pub const PP2_TYPE_MAX_EXPERIMENT: u8 = 0xF7;

// ----
// The following range of 8 values is reserved for future use, potentially to
// extend the protocol with multibyte type values.

/// reserved for future use (min range)
pub const PP2_TYPE_MIN_FUTURE: u8 = 0xF8;

/// reserved for future use (max range)
pub const PP2_TYPE_MAX_FUTURE: u8 = 0xFF;


//----
/// Max length of the TLV's payload uniq ID.
pub const MAX_UNIQ_ID_LEN_BYTES: u16 = 128;

/// Header length of TLV
pub const TLV_HEADER_LEN: u16 = 3;



// https://www.haproxy.org/download/3.2/doc/proxy-protocol.txt
// https://datatracker.ietf.org/doc/html/rfc7301

/// An OP codes definotions.
#[repr(u8)]
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum HdrV2Command
{
    LOCAL = 0,
    PROXY = 1,
    UNKNOWN,
}

impl From<HdrV2Command> for u8
{
    fn from(value: HdrV2Command) -> Self 
    {
        if value == HdrV2Command::UNKNOWN
        {
            panic!("can not encode the unknown command");
        }

        return value as u8;
    }
}

impl HdrV2Command
{
    pub(crate)
    fn decode(raw: u8) -> Self
    {
        match raw & protocol_raw::ProxyHdrV2::COMMAND_MASK
        {
            r if r == HdrV2Command::LOCAL.into() => return Self::LOCAL,
            r if r == HdrV2Command::PROXY.into() => return Self::PROXY,
            _ => return Self::UNKNOWN,
        }
    }
}

/// Defines the protocol versions.
#[repr(u8)]
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum ProtocolVersion
{
    V1 = 1,
    V2 = 2,
    UNKNOWN,
}

impl From<ProtocolVersion> for u8
{
    fn from(value: ProtocolVersion) -> Self 
    {
        if value == ProtocolVersion::UNKNOWN
        {
            panic!("can not encode the unknown version");
        }

        return (value as u8) << 4;
    }
}

impl ProtocolVersion
{
    pub(crate)
    fn decode(raw: u8) -> Self
    {
        match raw >> 4
        {
            1 => return Self::V1,
            2 => return Self::V2,
            _ => return Self::UNKNOWN,
        }
    }
}

bitflags! {
    /// A client flags.
    #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
    pub struct PP2TlvClient: u8 
    {
        /// client connected over SSL/TLS
        const PP2_CLIENT_SSL = 0x01;
        
        /// client provided a certificate over the current connection
        const PP2_CLIENT_CERT_CONN = 0x02;

        /// client provided a certificate at least once over the TLS session this 
        /// connection belongs to
        const PP2_CLIENT_CERT_SESS = 0x04;
    }
}

/// A specific for PP2Tlv SSL.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct PP2TlvsTypeSsl
{
    /// client came with something
    pub(crate) client: PP2TlvClient, 
                
    /// field will be zero if the client presented a certificate
    /// and it was successfully verified, and non-zero otherwise.
    pub(crate) verify: u32, 

    /// included sub TLVs
    pub(crate) sub_tlv: Vec<PP2Tlvs>
}

impl fmt::Display for PP2TlvsTypeSsl
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        write!(f, "CLIENT: {:?}, VERIFY: {}, TLVs: {}", 
            self.client, self.verify, 
            self.sub_tlv.iter().map(|t| t.to_string()).collect::<Vec<String>>().join(", "))
    }
}

/*
impl From<PP2TlvsTypeSsl> for PP2Tlvs
{
    fn from(value: PP2TlvsTypeSsl) -> Self where Self: PP2TlvDump
    {
        return Self::TypeSsl(value);
    }
}*/

/// Can be used for testing.
#[repr(u8)]
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum PP2Tlvs
{
    /// Application-Layer Protocol Negotiation (ALPN).
    TypeAlpn(Vec<Vec<u8>>) = Self::TYPE_ALPN,

    /// "SNI" i.e the "server_name" extension as defined by RFC3546
    /// UTF8-encoded string
    TypeAuthority(String) = Self::TYPE_AUTHORITY,

    /// 32-bit number storing the CRC32c checksum of the PROXY protocol header
    TypeCrc32c(u32) = Self::TYPE_CRC32C,

    /// The TLV of this type should be ignored when parsed. The value is zero or more
    /// bytes. Can be used for data padding or alignment. Note that it can be used
    /// to align only by 3 or more bytes because a TLV can not be smaller than that.
    TypeNoop = Self::TYPE_NOOP,

    /// opaque byte sequence of up to 128 bytes generated by the upstream proxy 
    /// that uniquely identifies the connection.
    TypeUniqId(Vec<u8>) = Self::TYPE_UNIQID,

    /// SSL properties
    TypeSsl
    {
        client: PP2TlvClient,
        verify: u32,
    } = Self::TYPE_SSL,

    /// US-ASCII string representation of the TLS version (format?)
    TypeSubtypeSslVersion(Cow<'static, str>) = Self::TYPE_SUBTYPE_SSL_VERSION,

    /// In all cases, the string representation (in UTF8) of the Common Name field
    /// (OID: 2.5.4.3) of the client certificate's Distinguished Name, is appended
    /// using the TLV format and the type PP2_SUBTYPE_SSL_CN. E.g. "example.com".
    TypeSubtypeSslCn(Cow<'static, str>) = Self::TYPE_SUBTYPE_SSL_CN,
    
    /// US-ASCII string name of the used cipher, for example "ECDHE-RSA-AES128-GCM-SHA256".
    TypeSubtypeSslCipher(Cow<'static, str>) = Self::TYPE_SUBTYPE_SSL_CIPHER,

    /// US-ASCII string name of the algorithm used to sign the certificate presented by the 
    /// frontend when the incoming connection was made over an SSL/TLS transport layer, for example
    /// "SHA256".
    TypeSubtypeSslSigAlg(Cow<'static, str>) = Self::TYPE_SUBTYPE_SSL_SIGALG,

    /// US-ASCII string name of the algorithm used to generate the key of the certificate 
    /// presented by the frontend when the incoming connection was made over an SSL/TLS 
    /// transport layer, for example "RSA2048".
    TypeSubtypeSslKeyAlg(Cow<'static, str>) = Self::TYPE_SUBTYPE_SSL_KEYALG,

    /// US-ASCII string representation of the namespace's name
    TypeNetNs(String) = Self::TYPE_NETNS,
}

impl fmt::Display for PP2Tlvs
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        let id : u8= self.into();

        match self
        {
            PP2Tlvs::TypeAlpn(alpns) => 
            {
                let alpns_dec = 
                    alpns
                        .iter()
                        .map(
                            |a| 
                            std
                                ::str
                                ::from_utf8(a)
                                    .map_err(|e| map_error!(MalformedData, "{}", e))
                        )
                        .collect::<HaProxRes<Vec<&str>>>()
                        .map_err(|_e| fmt::Error)?
                        .join(",");

                write!(f, "ALPNS({:02X}): {}", id, alpns_dec)
            },
            PP2Tlvs::TypeAuthority(sni) => 
                write!(f, "SNI({:02X}): {}", id, sni),
            PP2Tlvs::TypeCrc32c(crc) => 
                write!(f, "CRC({:02X}): {}", id, crc),
            PP2Tlvs::TypeNoop => 
                write!(f, "NOOP({:02X})", id),
            PP2Tlvs::TypeUniqId(items) => 
                write!(f, "UNIQID({:02X}): {:02X?}", id, items),
            PP2Tlvs::TypeSsl{client, verify} => 
                write!(f, "SSL({:02X}): client: {:?}, verify: {}", id, client, verify),
            PP2Tlvs::TypeSubtypeSslVersion(ver) => 
                write!(f, "SSL VERSION({:02X}): {}", id, ver),
            PP2Tlvs::TypeSubtypeSslCn(cn) => 
                write!(f, "SSL CN({:02X}): {}", id, cn),
            PP2Tlvs::TypeSubtypeSslCipher(c) => 
                write!(f, "SSL CIPHER({:02X}): {}", id, c),
            PP2Tlvs::TypeSubtypeSslSigAlg(sa) => 
                write!(f, "SSL SIGALG({:02X}): {}", id, sa),
            PP2Tlvs::TypeSubtypeSslKeyAlg(ka) => 
                write!(f, "SSL KEYALG({:02X}): {}", id, ka),
            PP2Tlvs::TypeNetNs(ns) => 
                write!(f, "NETNS({:02X}): {}", id, ns),
        }
    }
}

impl From<PP2Tlvs> for u8
{
    fn from(value: PP2Tlvs) -> Self 
    {
        return (&value).into();
    }
}

impl From<&PP2Tlvs> for u8
{
    fn from(value: &PP2Tlvs) -> Self 
    {
        return unsafe { *<*const _>::from(value).cast::<Self>() };
    }
}



impl PP2Tlvs
{
    /// A constraints by range of all types.
    pub const TLV_TYPE_MAIN_RANGES: &'static [RangeInclusive<u8>] = 
        &[
            Self::TYPE_ALPN..=Self::TYPE_SSL,  
            Self::TYPE_NETNS ..= Self::TYPE_NETNS
        ];

    /// A constraints for the SSL subtypes.
    pub const TLV_TYPE_SSL_SUB_RANGE: &'static [RangeInclusive<u8>] = 
        &[Self::TYPE_SUBTYPE_SSL_VERSION ..= Self::TYPE_SUBTYPE_SSL_KEYALG];

    pub const TYPE_ALPN: u8 = 0x01;

    pub const TYPE_AUTHORITY: u8 = 0x02;

    pub const TYPE_CRC32C: u8 = 0x03;

    pub const TYPE_NOOP: u8 = 0x04;

    pub const TYPE_UNIQID: u8 = 0x05;

    pub const TYPE_SSL: u8 = 0x20;

    pub const TYPE_SUBTYPE_SSL_VERSION: u8 = 0x21;

    pub const TYPE_SUBTYPE_SSL_CN: u8 = 0x22;
    
    pub const TYPE_SUBTYPE_SSL_CIPHER: u8 = 0x23;

    pub const TYPE_SUBTYPE_SSL_SIGALG: u8 = 0x24;

    pub const TYPE_SUBTYPE_SSL_KEYALG: u8 = 0x25;

    pub const TYPE_NETNS: u8 = 0x30;

    pub 
    fn contains_subtype(&self) -> bool
    {
        let Self::TypeSsl{ .. } = self else { return false };

        return true;
    }

    pub 
    fn conntains_subtype_discr(discr: u8) -> bool
    {
        return discr == Self::TYPE_SSL;
    }
}

/// A quote from protocol descr:
/// > other values are unspecified and must not be emitted in version 2 of this
/// > protocol and must be rejected as invalid by receivers.
#[repr(u8)]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum ProxyV2AddrType
{
    /// A quote from protocol descr:
    /// > the connection is forwarded for an unknown, unspecified
    /// > or unsupported protocol. The sender should use this family when sending
    /// > LOCAL commands or when dealing with unsupported protocol families. The
    /// > receiver is free to accept the connection anyway and use the real endpoint
    /// > addresses or to reject it. The receiver should ignore address information.
    AfUnspec = 0x00,

    /// A quote from protocol descr:
    /// > the forwarded connection uses the AF_INET address family
    /// > (IPv4). The addresses are exactly 4 bytes each in network byte order,
    /// > followed by transport protocol information (typically ports).
    AfInet = 0x01,

    /// A quote from protocol descr:
    /// > the forwarded connection uses the AF_INET6 address family
    /// > (IPv6). The addresses are exactly 16 bytes each in network byte order,
    /// > followed by transport protocol information (typically ports).
    AfInet6 = 0x02,

    /// A quote from protocol descr:
    /// > the forwarded connection uses the AF_UNIX address family
    /// > (UNIX). The addresses are exactly 108 bytes each.
    AfUnix = 0x03,
}

impl From<ProxyV2AddrType> for u8
{
    fn from(value: ProxyV2AddrType) -> Self 
    {
        return value as u8;
    }
}

impl ProxyV2AddrType
{
    pub const DEF_IPV4_ADDR_LEN: u16 = 12;
    pub const DEF_IPV6_ADDR_LEN: u16 = 36;
    pub const DEF_UNIX_ADDR_LEN: u16 = 216;

    pub(crate) 
    fn decode(raw: u8) -> HaProxRes<Self>
    {
        match raw >> 4
        {
            r if r == ProxyV2AddrType::AfUnspec.into() => 
                return Ok(Self::AfUnspec),
            r if r == ProxyV2AddrType::AfInet.into() => 
                return Ok(Self::AfInet),
            r if r == ProxyV2AddrType::AfInet6.into() => 
                return Ok(Self::AfInet6),
            r if r == ProxyV2AddrType::AfUnix.into() => 
                return Ok(Self::AfUnix),
            r => 
                return_error!(ProtocolUnknownData, "can not decode address type: '{:02X}'", r),
        }
    }

    pub 
    fn get_size_by_addr_family(&self) -> Option<u16>
    {
        match self
        {
            Self::AfUnspec => 
                return None,
            Self::AfInet => 
                return Some(Self::DEF_IPV4_ADDR_LEN),
            Self::AfInet6 => 
                return Some(Self::DEF_IPV6_ADDR_LEN),
            Self::AfUnix => 
                return Some(Self::DEF_UNIX_ADDR_LEN),
        }
    }
}


/// An address re-representation. Can be initialized using `TryFrom` 
/// implementations.
/// 
/// TryFrom("ip:port", "ip:port")
/// TryFrom(IpAddr, u16, IpAddr, u16)
/// TryFrom(net::SocketAddr, net::SocketAddr)
/// TryFrom(SocketAddr, SocketAddr)
/// 
/// The type will be determined automatically.
#[derive(Clone, Debug)]
pub enum ProxyV2Addr
{
    /// AF_INET, AF_INET6
    Ip
    {
        src: SocketAddr,
        dst: SocketAddr,
    },

    /// AF_UNIX
    Unix
    {
        src: net::SocketAddr,
        dst: net::SocketAddr,
    }
}

impl Eq for ProxyV2Addr {}

impl PartialEq for ProxyV2Addr
{
    fn eq(&self, other: &Self) -> bool 
    {
        match (self, other) 
        {
            (
                Self::Ip { src: l_src, dst: l_dst }, 
                Self::Ip { src: r_src, dst: r_dst }
            ) => 
                l_src == r_src && l_dst == r_dst,

            (
                Self::Unix { src: l_src, dst: l_dst }, 
                Self::Unix { src: r_src, dst: r_dst }
            ) => 
                l_src.as_pathname() == r_src.as_pathname() && l_dst.as_pathname() == r_dst.as_pathname(),
            _ => false,
        }
    }
}

impl fmt::Display for ProxyV2Addr
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        match self
        {
            ProxyV2Addr::Ip{ src, dst } => 
                write!(f, "SRC: {}, DST: {}", src, dst),
            ProxyV2Addr::Unix{ src, dst } => 
                write!(f, "SRC: {:?}, DST: {:?}", src, dst)
        }
    }
}

impl TryFrom<(IpAddr, u16, IpAddr, u16)> for ProxyV2Addr
{
    type Error = HaProxErr;

    /// # Arguments
    /// 
    /// * `value.0` - source IP address [IpAddr]
    /// 
    /// * `value.1` - source port [u16]
    /// 
    /// * `value.2` - destination IP address [IpAddr]
    /// 
    /// * `value.3` - destination port [u16]
    fn try_from(value: (IpAddr, u16, IpAddr, u16)) -> Result<Self, Self::Error> 
    {
        let src = SocketAddr::new(value.0, value.1);
        let dst = SocketAddr::new(value.2, value.3);

        return Ok(Self::Ip{ src: src, dst: dst });
    }
}

impl TryFrom<(SocketAddr, SocketAddr)> for ProxyV2Addr
{
    type Error = HaProxErr;

    /// # Arguments
    /// 
    /// * `value.0` - source address [SocketAddr]
    /// 
    /// * `value.1` - destination address [SocketAddr]
    fn try_from(value: (SocketAddr, SocketAddr)) -> Result<Self, Self::Error> 
    {
        return Ok(Self::Ip{ src: value.0, dst: value.1 });
    }
}

/// Attempts to convert from tuple (source, dst) from [net::SocketAddr] into [ProxyV2Addr].  
impl TryFrom<(net::SocketAddr, net::SocketAddr)> for ProxyV2Addr
{
    type Error = HaProxErr;

    /// # Arguments
    /// 
    /// * `value.0` - source address [net::SocketAddr]
    /// 
    /// * `value.1` - destination address [net::SocketAddr]
    fn try_from(value: (net::SocketAddr, net::SocketAddr)) -> Result<Self, Self::Error> 
    {
        return Ok(Self::Unix{ src: value.0, dst: value.1 });
    }
}

/// Attempts to convert tuple (source, destination) from [str] into [ProxyV2Addr].
impl TryFrom<(&str, &str)> for ProxyV2Addr
{
    type Error = HaProxErr;

    /// # Arguments
    /// 
    /// * `value.0` - source address [str]
    /// 
    /// * `value.1` - destination address [str]
    fn try_from(value: (&str, &str)) -> Result<Self, Self::Error> 
    {
        if let Ok(src) = SocketAddr::from_str(value.0)
        {
            let Ok(dst) = SocketAddr::from_str(value.1)
            else 
            {
                return_error!(ArgumentEinval, "can not convert '{}' to SocketAddr", 
                    common::sanitize_str_unicode(value.1));
            };

            return Ok(Self::Ip{ src: src, dst: dst });
        }
        else if let Ok(src) = net::SocketAddr::from_pathname(value.0)
        {
            let Ok(dst) = net::SocketAddr::from_pathname(value.1)
            else 
            {
                return_error!(ArgumentEinval, "can not convert '{}' to net::SocketAddr", 
                    common::sanitize_str_unicode(value.1));
            };

            return Ok(Self::Unix{ src: src, dst: dst });
        }
        else
        {
            return_error!(ArgumentEinval, "can not convert '{}' to either SocketAddr or net::SocketAddr", 
                common::sanitize_str_unicode(value.0));
        }
    }
}

impl ProxyV2Addr
{
    /// Returns the length in bytes for the current address. It returns full size, but not
    /// the actual ocupied length (for unix addresses).
    #[inline]
    pub 
    fn get_len(&self) -> u16
    {
        return self.as_addr_family().get_size_by_addr_family().unwrap();
    }

    /// Returns the address type.
    #[inline]
    pub 
    fn as_addr_family(&self) -> ProxyV2AddrType
    {
        match self
        {
            ProxyV2Addr::Ip{ src, .. } => 
            {
                if src.is_ipv4() == true
                {
                    return ProxyV2AddrType::AfInet;
                }
                else
                {
                    return ProxyV2AddrType::AfInet6;
                }
            }
            ProxyV2Addr::Unix{ .. } => 
                return ProxyV2AddrType::AfUnix
        }
    }

    /// Reads the address section of the HaProxy. The address family should be 
    /// obtained from the same packet before. The `cur` must point to the beginning
    /// of the address block.
    /// 
    /// # Returns
    /// 
    /// The [Result] is returned. The [Option::None] will be returned only if the
    /// `addr_fam` is [ProxyV2AddrType::AfUnspec].
    pub 
    fn read(addr_fam: ProxyV2AddrType, cur: &mut Cursor<&[u8]>) -> HaProxRes<Option<Self>>
    {
        match addr_fam
        {
            ProxyV2AddrType::AfUnspec => Ok(None),
            ProxyV2AddrType::AfInet => 
            {
                let src = IpAddr::from(Ipv4Addr::from_bits(cur.read_u32::<BigEndian>().map_err(common::map_io_err)?));
                let dst = IpAddr::from(Ipv4Addr::from_bits(cur.read_u32::<BigEndian>().map_err(common::map_io_err)?));
                let src_port = cur.read_u16::<BigEndian>().map_err(common::map_io_err)?;
                let dst_port = cur.read_u16::<BigEndian>().map_err(common::map_io_err)?;

                return Ok(Some(Self::try_from((src, src_port, dst, dst_port))?));
            },
            ProxyV2AddrType::AfInet6 => 
            {
                let src = IpAddr::from(Ipv6Addr::from_bits(cur.read_u128::<BigEndian>().map_err(common::map_io_err)?));
                let dst = IpAddr::from(Ipv6Addr::from_bits(cur.read_u128::<BigEndian>().map_err(common::map_io_err)?));
                let src_port = cur.read_u16::<BigEndian>().map_err(common::map_io_err)?;
                let dst_port = cur.read_u16::<BigEndian>().map_err(common::map_io_err)?;

                return Ok(Some(Self::try_from((src, src_port, dst, dst_port))?));
            },
            ProxyV2AddrType::AfUnix => 
            {
                let mut n_src: [u8; HEADER_UNIX_ADDR_LEN] = [0_u8; HEADER_UNIX_ADDR_LEN];
                cur.read(&mut n_src).map_err(common::map_io_err)?;

                let mut n_dst: [u8; HEADER_UNIX_ADDR_LEN] = [0_u8; HEADER_UNIX_ADDR_LEN];
                cur.read(&mut n_dst).map_err(common::map_io_err)?;

                let src_s = 
                    net::SocketAddr::from_pathname(
                        CStr::from_bytes_until_nul(&n_src)
                            .map_err(|e| 
                                map_error!(MalformedData, "cannot read unix path, error: {}", e)
                            )?
                            .to_str()
                            .map_err(|e|
                                map_error!(MalformedData, "cannot read unix path, error: {}", e)
                            )?
                    )
                    .map_err(|e|
                        map_error!(MalformedData, "cannot read unix path, error: {}", e)
                    )?;

                let dst_s = 
                    net::SocketAddr::from_pathname(
                        CStr::from_bytes_until_nul(&n_dst)
                            .map_err(|e| 
                                map_error!(MalformedData, "cannot read unix path, error: {}", e)
                            )?
                            .to_str()
                            .map_err(|e|
                                map_error!(MalformedData, "cannot read unix path, error: {}", e)
                            )?
                    )
                    .map_err(|e|
                        map_error!(MalformedData, "cannot read unix path, error: {}", e)
                    )?;

                return Ok(Some(Self::try_from((src_s, dst_s))?));
            },
        }
    }

    /// Writes the content of the current instance to packet in format of 
    /// the HaProxy address. The `cur` [Cursor] should point to the
    /// beginning of the address block.
    pub  
    fn write(&self, cur: &mut Cursor<Vec<u8>>) -> HaProxRes<()>
    {
        match self
        {
            ProxyV2Addr::Ip{ src, dst } => 
            {
                match src.ip()
                {
                    IpAddr::V4(ipv4_addr) => 
                        cur.write_u32::<BigEndian>(ipv4_addr.to_bits()).map_err(common::map_io_err)?,
                    IpAddr::V6(ipv6_addr) => 
                        cur.write_u128::<BigEndian>(ipv6_addr.to_bits()).map_err(common::map_io_err)?,
                }

                match dst.ip()
                {
                    IpAddr::V4(ipv4_addr) => 
                        cur.write_u32::<BigEndian>(ipv4_addr.to_bits()).map_err(common::map_io_err)?,
                    IpAddr::V6(ipv6_addr) => 
                        cur.write_u128::<BigEndian>(ipv6_addr.to_bits()).map_err(common::map_io_err)?,
                }

                cur.write_u16::<BigEndian>(src.port()).map_err(common::map_io_err)?;
                cur.write_u16::<BigEndian>(dst.port()).map_err(common::map_io_err)?;
            },
            ProxyV2Addr::Unix { src, dst } => 
            {
                let src_p = 
                    src.as_pathname().ok_or_else(|| map_error!(ArgumentEinval, "UNIX src socket addr is not path"))?;
                let dst_p = 
                    dst.as_pathname().ok_or_else(|| map_error!(ArgumentEinval, "UNIX src socket addr is not path"))?;

                let src_b = src_p.as_os_str().as_bytes();
                let dst_b = dst_p.as_os_str().as_bytes();

                if src_b.len() > HEADER_UNIX_ADDR_LEN
                {
                    return_error!(ArgumentEinval, "socket path: '{}' longer than: '{}'", 
                        src_p.display(), HEADER_UNIX_ADDR_LEN);
                }
                else if dst_b.len() > HEADER_UNIX_ADDR_LEN
                {
                    return_error!(ArgumentEinval, "socket path: '{}' longer than: '{}'", 
                        dst_p.display(), HEADER_UNIX_ADDR_LEN);
                }

                
                let mut n_src: [u8; HEADER_UNIX_ADDR_LEN] = [0_u8; HEADER_UNIX_ADDR_LEN];
                n_src[0..src_b.len()].copy_from_slice(src_b);

                cur.write_all(&n_src).map_err(common::map_io_err)?;

                let mut n_dst: [u8; HEADER_UNIX_ADDR_LEN] = [0_u8; HEADER_UNIX_ADDR_LEN];
                n_dst[0..dst_b.len()].copy_from_slice(dst_b);

                cur.write_all(&n_dst).map_err(common::map_io_err)?;
            }
        }

        return Ok(());
    }
}

/// A transport family.
/// > Other values are unspecified and must not be emitted in version 2 of this
/// > protocol and must be rejected as invalid by receivers.`
#[repr(u8)]
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum ProxyTransportFam
{
    /// > the connection is forwarded for an unknown, unspecified
    /// > or unsupported protocol. The sender should use this family when sending
    /// > LOCAL commands or when dealing with unsupported protocol families. The
    /// > receiver is free to accept the connection anyway and use the real endpoint
    /// > addresses or to reject it. The receiver should ignore address information.
    UNSPEC = 0x00,

    /// > the forwarded connection uses a SOCK_STREAM protocol (eg:
    /// > TCP or UNIX_STREAM). When used with AF_INET/AF_INET6 (TCP), the addresses
    /// > are followed by the source and destination ports represented on 2 bytes
    /// > each in network byte order.
    STREAM,

    /// > the forwarded connection uses a SOCK_DGRAM protocol (eg:
    /// > UDP or UNIX_DGRAM). When used with AF_INET/AF_INET6 (UDP), the addresses
    /// > are followed by the source and destination ports represented on 2 bytes
    /// > each in network byte order.
    DGRAM,
}

impl fmt::Display for ProxyTransportFam
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result 
    {
        match self
        {
            Self::UNSPEC => write!(f, "UNSPEC"),
            Self::STREAM => write!(f, "STREAM"),
            Self::DGRAM => write!(f, "DGRAM"),
        }
    }
}

impl From<ProxyTransportFam> for u8
{
    fn from(value: ProxyTransportFam) -> Self 
    {
        return value as u8;
    }
}

impl From<&ProxyTransportFam> for u8
{
    fn from(value: &ProxyTransportFam) -> Self 
    {
        return unsafe { *<*const _>::from(value).cast::<Self>() };
    }
}

impl ProxyTransportFam
{
    pub(crate) 
    fn decode(value: u8) -> HaProxRes<Self>
    {
        match value & protocol_raw::ProxyHdrV2::TRANSPT_MASK
        {
            v if ProxyTransportFam::UNSPEC as u8 == v => 
                return Ok(Self::UNSPEC),
            v if ProxyTransportFam::STREAM as u8 == v => 
                return Ok(Self::STREAM),
            v if ProxyTransportFam::DGRAM as u8 == v => 
                return Ok(Self::DGRAM),
            _ => 
                return_error!(ProtocolUnknownData, "unknown transport {:02X}", value)
        }
    }
}

#[cfg(test)]
mod tests
{
    use core::fmt;
    use std::{slice, time::Instant};

    use crate::protocol::{protocol::{PP2TlvClient, ProxyTransportFam, ProxyV2Addr}, protocol_composer::{HdrV2OpLocal, HdrV2OpProxy, ProxyHdrV2}, protocol_raw::{self, HEADER_MAGIC_V2, HEADER_MAGINC_LEN}, PP2TlvUniqId};
    #[test]
    fn test_hdr1()
    {
        
        for _ in 0..10
        {
            let s = Instant::now();
            let _local = ProxyHdrV2::<HdrV2OpLocal>::new();

            let e = s.elapsed();

            println!("{:?}", e);
        }

        let buf = ProxyHdrV2::<HdrV2OpLocal>::new();


        
        let mut sign: [u8; HEADER_MAGINC_LEN] = [0_u8; HEADER_MAGINC_LEN];
        sign.copy_from_slice(HEADER_MAGIC_V2);
        let ctrl =
            vec![
                protocol_raw::ProxyHdrV2
                {
                    signature: sign,
                    ver_cmd: 0x20,
                    fam: 0,
                    len: 0,
                    address: [],
                }
            ];

            println!("{} {}", buf.len(), size_of::<protocol_raw::ProxyHdrV2>());
        let ctrl_buf = unsafe { slice::from_raw_parts(ctrl.as_ptr() as *const _ as *const u8, size_of::<protocol_raw::ProxyHdrV2>()) };

        assert_eq!(buf.as_slice(), ctrl_buf);
    }

    #[test]
    fn test_proxy_compose()
    {
        struct UniqIdHolder;
        impl UniqIdHolder
        {
            const ID: &'static [u8] = b"ABCD12345678901234567890";
        }
        impl fmt::Display for UniqIdHolder
        {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result 
            {
                write!(f, "")
            }
        }
        impl PP2TlvUniqId for UniqIdHolder
        {
            fn into_bytes(&self) -> Vec<u8> 
            {
                Self::ID.to_vec()
            }
        
            fn get_len(&self) -> u16 
            {
                Self::ID.len() as u16
            }
        }
        for _ in 0..10
        {
            let addr: ProxyV2Addr = ProxyV2Addr::try_from(("127.0.0.1:4567", "127.0.0.1:443")).unwrap();
            let id = UniqIdHolder;

            let s = Instant::now();
            let mut proxy = 
                ProxyHdrV2::<HdrV2OpProxy>::new(ProxyTransportFam::STREAM, addr).unwrap();

            let mut plts = proxy.set_plts();
            plts.add_crc32().unwrap();
            plts.add_authority("www.example.com").unwrap();
            plts.add_uniq_id(id).unwrap();
            drop(plts);

            let e = s.elapsed();

            println!("prep: {:?}", e);
        
            let s = Instant::now();
            let _buf: Vec<u8> = proxy.try_into().unwrap();
            let e = s.elapsed();

            println!("{:?}", e);
        }

       // assert_eq!(buf.as_slice(), ctrl_buf);
       return;
    }

    #[test]
    fn test_hdr2()
    {
        let addr: ProxyV2Addr = ProxyV2Addr::try_from(("127.0.0.1:39754", "127.0.0.67:11883")).unwrap();

        let s = Instant::now();
        let mut proxy = 
            ProxyHdrV2::<HdrV2OpProxy>::new(ProxyTransportFam::STREAM, addr).unwrap();
      
        let plts = proxy.set_plts();

        let mut sub_ssl = plts.add_ssl(PP2TlvClient::PP2_CLIENT_SSL, 0).unwrap();

        sub_ssl.add_ssl_sub_version("TLSv1.2").unwrap();

        sub_ssl.done().unwrap();


        let e = s.elapsed();

        println!("prep: {:?}", e);

        let s = Instant::now();
        let buf: Vec<u8> = proxy.try_into().unwrap();
        let e = s.elapsed();

        println!("{:?}", e);
        
        
        let reference = 
            b"\x0d\x0a\x0d\x0a\x00\x0d\x0a\x51\x55\x49\x54\x0a\x21\x11\x00\x1e\
            \x7f\x00\x00\x01\x7f\x00\x00\x43\x9b\x4a\x2e\x6b\x20\x00\x0f\x01\
            \x00\x00\x00\x00\x21\x00\x07\x54\x4c\x53\x76\x31\x2e\x32";

        //println!("{:02X?}\n{:02X?}", buf.as_slice(), reference.as_slice());

        assert_eq!(buf.as_slice(), reference.as_slice());
    }
}