Update

vendor/github.com/pires/go-proxyproto/addr_proto.go

@@ -0,0 +1,62 @@
+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)
+}