Update

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

@@ -0,0 +1,132 @@
+// Type-Length-Value splitting and parsing for proxy protocol V2
+// See spec https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt sections 2.2 to 2.7 and
+
+package proxyproto
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math"
+)
+
+const (
+	// Section 2.2
+	PP2_TYPE_ALPN           PP2Type = 0x01
+	PP2_TYPE_AUTHORITY      PP2Type = 0x02
+	PP2_TYPE_CRC32C         PP2Type = 0x03
+	PP2_TYPE_NOOP           PP2Type = 0x04
+	PP2_TYPE_UNIQUE_ID      PP2Type = 0x05
+	PP2_TYPE_SSL            PP2Type = 0x20
+	PP2_SUBTYPE_SSL_VERSION PP2Type = 0x21
+	PP2_SUBTYPE_SSL_CN      PP2Type = 0x22
+	PP2_SUBTYPE_SSL_CIPHER  PP2Type = 0x23
+	PP2_SUBTYPE_SSL_SIG_ALG PP2Type = 0x24
+	PP2_SUBTYPE_SSL_KEY_ALG PP2Type = 0x25
+	PP2_TYPE_NETNS          PP2Type = 0x30
+
+	// Section 2.2.7, reserved types
+	PP2_TYPE_MIN_CUSTOM     PP2Type = 0xE0
+	PP2_TYPE_MAX_CUSTOM     PP2Type = 0xEF
+	PP2_TYPE_MIN_EXPERIMENT PP2Type = 0xF0
+	PP2_TYPE_MAX_EXPERIMENT PP2Type = 0xF7
+	PP2_TYPE_MIN_FUTURE     PP2Type = 0xF8
+	PP2_TYPE_MAX_FUTURE     PP2Type = 0xFF
+)
+
+var (
+	ErrTruncatedTLV    = errors.New("proxyproto: truncated TLV")
+	ErrMalformedTLV    = errors.New("proxyproto: malformed TLV Value")
+	ErrIncompatibleTLV = errors.New("proxyproto: incompatible TLV type")
+)
+
+// PP2Type is the proxy protocol v2 type
+type PP2Type byte
+
+// TLV is a uninterpreted Type-Length-Value for V2 protocol, see section 2.2
+type TLV struct {
+	Type  PP2Type
+	Value []byte
+}
+
+// SplitTLVs splits the Type-Length-Value vector, returns the vector or an error.
+func SplitTLVs(raw []byte) ([]TLV, error) {
+	var tlvs []TLV
+	for i := 0; i < len(raw); {
+		tlv := TLV{
+			Type: PP2Type(raw[i]),
+		}
+		if len(raw)-i <= 2 {
+			return nil, ErrTruncatedTLV
+		}
+		tlvLen := int(binary.BigEndian.Uint16(raw[i+1 : i+3])) // Max length = 65K
+		i += 3
+		if i+tlvLen > len(raw) {
+			return nil, ErrTruncatedTLV
+		}
+		// Ignore no-op padding
+		if tlv.Type != PP2_TYPE_NOOP {
+			tlv.Value = make([]byte, tlvLen)
+			copy(tlv.Value, raw[i:i+tlvLen])
+		}
+		i += tlvLen
+		tlvs = append(tlvs, tlv)
+	}
+	return tlvs, nil
+}
+
+// JoinTLVs joins multiple Type-Length-Value records.
+func JoinTLVs(tlvs []TLV) ([]byte, error) {
+	var raw []byte
+	for _, tlv := range tlvs {
+		if len(tlv.Value) > math.MaxUint16 {
+			return nil, fmt.Errorf("proxyproto: cannot format TLV %v with length %d", tlv.Type, len(tlv.Value))
+		}
+		var length [2]byte
+		binary.BigEndian.PutUint16(length[:], uint16(len(tlv.Value)))
+		raw = append(raw, byte(tlv.Type))
+		raw = append(raw, length[:]...)
+		raw = append(raw, tlv.Value...)
+	}
+	return raw, nil
+}
+
+// Registered is true if the type is registered in the spec, see section 2.2
+func (p PP2Type) Registered() bool {
+	switch p {
+	case PP2_TYPE_ALPN,
+		PP2_TYPE_AUTHORITY,
+		PP2_TYPE_CRC32C,
+		PP2_TYPE_NOOP,
+		PP2_TYPE_UNIQUE_ID,
+		PP2_TYPE_SSL,
+		PP2_SUBTYPE_SSL_VERSION,
+		PP2_SUBTYPE_SSL_CN,
+		PP2_SUBTYPE_SSL_CIPHER,
+		PP2_SUBTYPE_SSL_SIG_ALG,
+		PP2_SUBTYPE_SSL_KEY_ALG,
+		PP2_TYPE_NETNS:
+		return true
+	}
+	return false
+}
+
+// App is true if the type is reserved for application specific data, see section 2.2.7
+func (p PP2Type) App() bool {
+	return p >= PP2_TYPE_MIN_CUSTOM && p <= PP2_TYPE_MAX_CUSTOM
+}
+
+// Experiment is true if the type is reserved for temporary experimental use by application developers, see section 2.2.7
+func (p PP2Type) Experiment() bool {
+	return p >= PP2_TYPE_MIN_EXPERIMENT && p <= PP2_TYPE_MAX_EXPERIMENT
+}
+
+// Future is true is the type is reserved for future use, see section 2.2.7
+func (p PP2Type) Future() bool {
+	return p >= PP2_TYPE_MIN_FUTURE
+}
+
+// Spec is true if the type is covered by the spec, see section 2.2 and 2.2.7
+func (p PP2Type) Spec() bool {
+	return p.Registered() || p.App() || p.Experiment() || p.Future()
+}