TUN-6666: Define packet package

This package defines IP and ICMP packet, decoders, encoder and flow

vendor/github.com/google/gopacket/layers/eap.go

@@ -0,0 +1,114 @@
+// Copyright 2012 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+
+package layers
+
+import (
+	"encoding/binary"
+	"fmt"
+	"github.com/google/gopacket"
+)
+
+type EAPCode uint8
+type EAPType uint8
+
+const (
+	EAPCodeRequest  EAPCode = 1
+	EAPCodeResponse EAPCode = 2
+	EAPCodeSuccess  EAPCode = 3
+	EAPCodeFailure  EAPCode = 4
+
+	// EAPTypeNone means that this EAP layer has no Type or TypeData.
+	// Success and Failure EAPs will have this set.
+	EAPTypeNone EAPType = 0
+
+	EAPTypeIdentity     EAPType = 1
+	EAPTypeNotification EAPType = 2
+	EAPTypeNACK         EAPType = 3
+	EAPTypeOTP          EAPType = 4
+	EAPTypeTokenCard    EAPType = 5
+)
+
+// EAP defines an Extensible Authentication Protocol (rfc 3748) layer.
+type EAP struct {
+	BaseLayer
+	Code     EAPCode
+	Id       uint8
+	Length   uint16
+	Type     EAPType
+	TypeData []byte
+}
+
+// LayerType returns LayerTypeEAP.
+func (e *EAP) LayerType() gopacket.LayerType { return LayerTypeEAP }
+
+// DecodeFromBytes decodes the given bytes into this layer.
+func (e *EAP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+	if len(data) < 4 {
+		df.SetTruncated()
+		return fmt.Errorf("EAP length %d too short", len(data))
+	}
+	e.Code = EAPCode(data[0])
+	e.Id = data[1]
+	e.Length = binary.BigEndian.Uint16(data[2:4])
+	if len(data) < int(e.Length) {
+		df.SetTruncated()
+		return fmt.Errorf("EAP length %d too short, %d expected", len(data), e.Length)
+	}
+	switch {
+	case e.Length > 4:
+		e.Type = EAPType(data[4])
+		e.TypeData = data[5:]
+	case e.Length == 4:
+		e.Type = 0
+		e.TypeData = nil
+	default:
+		return fmt.Errorf("invalid EAP length %d", e.Length)
+	}
+	e.BaseLayer.Contents = data[:e.Length]
+	e.BaseLayer.Payload = data[e.Length:] // Should be 0 bytes
+	return nil
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (e *EAP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	if opts.FixLengths {
+		e.Length = uint16(len(e.TypeData) + 1)
+	}
+	size := len(e.TypeData) + 4
+	if size > 4 {
+		size++
+	}
+	bytes, err := b.PrependBytes(size)
+	if err != nil {
+		return err
+	}
+	bytes[0] = byte(e.Code)
+	bytes[1] = e.Id
+	binary.BigEndian.PutUint16(bytes[2:], e.Length)
+	if size > 4 {
+		bytes[4] = byte(e.Type)
+		copy(bytes[5:], e.TypeData)
+	}
+	return nil
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode.
+func (e *EAP) CanDecode() gopacket.LayerClass {
+	return LayerTypeEAP
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (e *EAP) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypeZero
+}
+
+func decodeEAP(data []byte, p gopacket.PacketBuilder) error {
+	e := &EAP{}
+	return decodingLayerDecoder(e, data, p)
+}