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