Method DecodeFromBytes

layers/eapol.go:185–239

DecodeFromBytes decodes the given bytes into this layer.

(data []byte, df gopacket.DecodeFeedback)

// DecodeFromBytes decodes the given bytes into this layer.
func (ek *EAPOLKey) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
	if len(data) < eapolKeyFrameLen {
		df.SetTruncated()
		return fmt.Errorf("EAPOLKey length %v too short, %v required",
			len(data), eapolKeyFrameLen)
	}

	ek.KeyDescriptorType = EAPOLKeyDescriptorType(data[0])

	info := binary.BigEndian.Uint16(data[1:3])
	ek.KeyDescriptorVersion = EAPOLKeyDescriptorVersion(info & 0x0007)
	ek.KeyType = EAPOLKeyType((info & 0x0008) >> 3)
	ek.KeyIndex = uint8((info & 0x0030) >> 4)
	ek.Install = (info & 0x0040) != 0
	ek.KeyACK = (info & 0x0080) != 0
	ek.KeyMIC = (info & 0x0100) != 0
	ek.Secure = (info & 0x0200) != 0
	ek.MICError = (info & 0x0400) != 0
	ek.Request = (info & 0x0800) != 0
	ek.HasEncryptedKeyData = (info & 0x1000) != 0
	ek.SMKMessage = (info & 0x2000) != 0

	ek.KeyLength = binary.BigEndian.Uint16(data[3:5])
	ek.ReplayCounter = binary.BigEndian.Uint64(data[5:13])

	ek.Nonce = data[13:45]
	ek.IV = data[45:61]
	ek.RSC = binary.BigEndian.Uint64(data[61:69])
	ek.ID = binary.BigEndian.Uint64(data[69:77])
	ek.MIC = data[77:93]

	ek.KeyDataLength = binary.BigEndian.Uint16(data[93:95])

	totalLength := eapolKeyFrameLen + int(ek.KeyDataLength)
	if len(data) < totalLength {
		df.SetTruncated()
		return fmt.Errorf("EAPOLKey data length %d too short, %d required",
			len(data)-eapolKeyFrameLen, ek.KeyDataLength)
	}

	if ek.HasEncryptedKeyData {
		ek.EncryptedKeyData = data[eapolKeyFrameLen:totalLength]
		ek.BaseLayer = BaseLayer{
			Contents: data[:totalLength],
			Payload:  data[totalLength:],
		}
	} else {
		ek.BaseLayer = BaseLayer{
			Contents: data[:eapolKeyFrameLen],
			Payload:  data[eapolKeyFrameLen:],
		}
	}

	return nil
}

// SerializeTo writes the serialized form of this layer into the
// SerializationBuffer, implementing gopacket.SerializableLayer.