从proxy获取client ip地址

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

@@ -0,0 +1,71 @@
+package proxyproto
+
+// AddressFamilyAndProtocol represents address family and transport protocol.
+type AddressFamilyAndProtocol byte
+
+const (
+	UNSPEC       = '\x00'
+	TCPv4        = '\x11'
+	UDPv4        = '\x12'
+	TCPv6        = '\x21'
+	UDPv6        = '\x22'
+	UnixStream   = '\x31'
+	UnixDatagram = '\x32'
+)
+
+var supportedTransportProtocol = map[AddressFamilyAndProtocol]bool{
+	TCPv4:        true,
+	UDPv4:        true,
+	TCPv6:        true,
+	UDPv6:        true,
+	UnixStream:   true,
+	UnixDatagram: true,
+}
+
+// IsIPv4 returns true if the address family is IPv4 (AF_INET4), false otherwise.
+func (ap AddressFamilyAndProtocol) IsIPv4() bool {
+	return 0x10 == ap&0xF0
+}
+
+// IsIPv6 returns true if the address family is IPv6 (AF_INET6), false otherwise.
+func (ap AddressFamilyAndProtocol) IsIPv6() bool {
+	return 0x20 == ap&0xF0
+}
+
+// IsUnix returns true if the address family is UNIX (AF_UNIX), false otherwise.
+func (ap AddressFamilyAndProtocol) IsUnix() bool {
+	return 0x30 == ap&0xF0
+}
+
+// IsStream returns true if the transport protocol is TCP or STREAM (SOCK_STREAM), false otherwise.
+func (ap AddressFamilyAndProtocol) IsStream() bool {
+	return 0x01 == ap&0x0F
+}
+
+// IsDatagram returns true if the transport protocol is UDP or DGRAM (SOCK_DGRAM), false otherwise.
+func (ap AddressFamilyAndProtocol) IsDatagram() bool {
+	return 0x02 == ap&0x0F
+}
+
+// IsUnspec returns true if the transport protocol or address family is unspecified, false otherwise.
+func (ap AddressFamilyAndProtocol) IsUnspec() bool {
+	return (0x00 == ap&0xF0) || (0x00 == ap&0x0F)
+}
+
+func (ap AddressFamilyAndProtocol) toByte() byte {
+	if ap.IsIPv4() && ap.IsStream() {
+		return TCPv4
+	} else if ap.IsIPv4() && ap.IsDatagram() {
+		return UDPv4
+	} else if ap.IsIPv6() && ap.IsStream() {
+		return TCPv6
+	} else if ap.IsIPv6() && ap.IsDatagram() {
+		return UDPv6
+	} else if ap.IsUnix() && ap.IsStream() {
+		return UnixStream
+	} else if ap.IsUnix() && ap.IsDatagram() {
+		return UnixDatagram
+	}
+
+	return UNSPEC
+}