source: code/trunk/vendor/github.com/pires/go-proxyproto/addr_proto.go@ 824

package proxyproto

// AddressFamilyAndProtocol represents address family and transport protocol.
type AddressFamilyAndProtocol byte

const (
        UNSPEC       AddressFamilyAndProtocol = '\x00'
        TCPv4        AddressFamilyAndProtocol = '\x11'
        UDPv4        AddressFamilyAndProtocol = '\x12'
        TCPv6        AddressFamilyAndProtocol = '\x21'
        UDPv6        AddressFamilyAndProtocol = '\x22'
        UnixStream   AddressFamilyAndProtocol = '\x31'
        UnixDatagram AddressFamilyAndProtocol = '\x32'
)

// IsIPv4 returns true if the address family is IPv4 (AF_INET4), false otherwise.
func (ap AddressFamilyAndProtocol) IsIPv4() bool {
        return ap&0xF0 == 0x10
}

// IsIPv6 returns true if the address family is IPv6 (AF_INET6), false otherwise.
func (ap AddressFamilyAndProtocol) IsIPv6() bool {
        return ap&0xF0 == 0x20
}

// IsUnix returns true if the address family is UNIX (AF_UNIX), false otherwise.
func (ap AddressFamilyAndProtocol) IsUnix() bool {
        return ap&0xF0 == 0x30
}

// IsStream returns true if the transport protocol is TCP or STREAM (SOCK_STREAM), false otherwise.
func (ap AddressFamilyAndProtocol) IsStream() bool {
        return ap&0x0F == 0x01
}

// IsDatagram returns true if the transport protocol is UDP or DGRAM (SOCK_DGRAM), false otherwise.
func (ap AddressFamilyAndProtocol) IsDatagram() bool {
        return ap&0x0F == 0x02
}

// IsUnspec returns true if the transport protocol or address family is unspecified, false otherwise.
func (ap AddressFamilyAndProtocol) IsUnspec() bool {
        return (ap&0xF0 == 0x00) || (ap&0x0F == 0x00)
}

func (ap AddressFamilyAndProtocol) toByte() byte {
        if ap.IsIPv4() && ap.IsStream() {
                return byte(TCPv4)
        } else if ap.IsIPv4() && ap.IsDatagram() {
                return byte(UDPv4)
        } else if ap.IsIPv6() && ap.IsStream() {
                return byte(TCPv6)
        } else if ap.IsIPv6() && ap.IsDatagram() {
                return byte(UDPv6)
        } else if ap.IsUnix() && ap.IsStream() {
                return byte(UnixStream)
        } else if ap.IsUnix() && ap.IsDatagram() {
                return byte(UnixDatagram)
        }

        return byte(UNSPEC)
}