ie.go

// Copyright 2019-2024 go-pfcp authors. All rights reserved.
// Use of this source code is governed by a MIT-style license that can be
// found in the LICENSE file.

package ie

import (
	"encoding/binary"
	"io"
	"time"

	"github.com/wmnsk/go-pfcp/internal/logger"
	"github.com/wmnsk/go-pfcp/internal/utils"
)

// IE Type definitions.
const (
	_                                                                uint16 = 0
	CreatePDR                                                        uint16 = 1
	PDI                                                              uint16 = 2
	CreateFAR                                                        uint16 = 3
	ForwardingParameters                                             uint16 = 4
	DuplicatingParameters                                            uint16 = 5
	CreateURR                                                        uint16 = 6
	CreateQER                                                        uint16 = 7
	CreatedPDR                                                       uint16 = 8
	UpdatePDR                                                        uint16 = 9
	UpdateFAR                                                        uint16 = 10
	UpdateForwardingParameters                                       uint16 = 11
	UpdateBARWithinSessionReportResponse                             uint16 = 12
	UpdateURR                                                        uint16 = 13
	UpdateQER                                                        uint16 = 14
	RemovePDR                                                        uint16 = 15
	RemoveFAR                                                        uint16 = 16
	RemoveURR                                                        uint16 = 17
	RemoveQER                                                        uint16 = 18
	Cause                                                            uint16 = 19
	SourceInterface                                                  uint16 = 20
	FTEID                                                            uint16 = 21
	NetworkInstance                                                  uint16 = 22
	SDFFilter                                                        uint16 = 23
	ApplicationID                                                    uint16 = 24
	GateStatus                                                       uint16 = 25
	MBR                                                              uint16 = 26
	GBR                                                              uint16 = 27
	QERCorrelationID                                                 uint16 = 28
	Precedence                                                       uint16 = 29
	TransportLevelMarking                                            uint16 = 30
	VolumeThreshold                                                  uint16 = 31
	TimeThreshold                                                    uint16 = 32
	MonitoringTime                                                   uint16 = 33
	SubsequentVolumeThreshold                                        uint16 = 34
	SubsequentTimeThreshold                                          uint16 = 35
	InactivityDetectionTime                                          uint16 = 36
	ReportingTriggers                                                uint16 = 37
	RedirectInformation                                              uint16 = 38
	ReportType                                                       uint16 = 39
	OffendingIE                                                      uint16 = 40
	ForwardingPolicy                                                 uint16 = 41
	DestinationInterface                                             uint16 = 42
	UPFunctionFeatures                                               uint16 = 43
	ApplyAction                                                      uint16 = 44
	DownlinkDataServiceInformation                                   uint16 = 45
	DownlinkDataNotificationDelay                                    uint16 = 46
	DLBufferingDuration                                              uint16 = 47
	DLBufferingSuggestedPacketCount                                  uint16 = 48
	PFCPSMReqFlags                                                   uint16 = 49
	PFCPSRRspFlags                                                   uint16 = 50
	LoadControlInformation                                           uint16 = 51
	SequenceNumber                                                   uint16 = 52
	Metric                                                           uint16 = 53
	OverloadControlInformation                                       uint16 = 54
	Timer                                                            uint16 = 55
	PDRID                                                            uint16 = 56
	FSEID                                                            uint16 = 57
	ApplicationIDsPFDs                                               uint16 = 58
	PFDContext                                                       uint16 = 59
	NodeID                                                           uint16 = 60
	PFDContents                                                      uint16 = 61
	MeasurementMethod                                                uint16 = 62
	UsageReportTrigger                                               uint16 = 63
	MeasurementPeriod                                                uint16 = 64
	FQCSID                                                           uint16 = 65
	VolumeMeasurement                                                uint16 = 66
	DurationMeasurement                                              uint16 = 67
	ApplicationDetectionInformation                                  uint16 = 68
	TimeOfFirstPacket                                                uint16 = 69
	TimeOfLastPacket                                                 uint16 = 70
	QuotaHoldingTime                                                 uint16 = 71
	DroppedDLTrafficThreshold                                        uint16 = 72
	VolumeQuota                                                      uint16 = 73
	TimeQuota                                                        uint16 = 74
	StartTime                                                        uint16 = 75
	EndTime                                                          uint16 = 76
	QueryURR                                                         uint16 = 77
	UsageReportWithinSessionModificationResponse                     uint16 = 78
	UsageReportWithinSessionDeletionResponse                         uint16 = 79
	UsageReportWithinSessionReportRequest                            uint16 = 80
	URRID                                                            uint16 = 81
	LinkedURRID                                                      uint16 = 82
	DownlinkDataReport                                               uint16 = 83
	OuterHeaderCreation                                              uint16 = 84
	CreateBAR                                                        uint16 = 85
	UpdateBARWithinSessionModificationRequest                        uint16 = 86
	RemoveBAR                                                        uint16 = 87
	BARID                                                            uint16 = 88
	CPFunctionFeatures                                               uint16 = 89
	UsageInformation                                                 uint16 = 90
	ApplicationInstanceID                                            uint16 = 91
	FlowInformation                                                  uint16 = 92
	UEIPAddress                                                      uint16 = 93
	PacketRate                                                       uint16 = 94
	OuterHeaderRemoval                                               uint16 = 95
	RecoveryTimeStamp                                                uint16 = 96
	DLFlowLevelMarking                                               uint16 = 97
	HeaderEnrichment                                                 uint16 = 98
	ErrorIndicationReport                                            uint16 = 99
	MeasurementInformation                                           uint16 = 100
	NodeReportType                                                   uint16 = 101
	UserPlanePathFailureReport                                       uint16 = 102
	RemoteGTPUPeer                                                   uint16 = 103
	URSEQN                                                           uint16 = 104
	UpdateDuplicatingParameters                                      uint16 = 105
	ActivatePredefinedRules                                          uint16 = 106
	DeactivatePredefinedRules                                        uint16 = 107
	FARID                                                            uint16 = 108
	QERID                                                            uint16 = 109
	OCIFlags                                                         uint16 = 110
	PFCPAssociationReleaseRequest                                    uint16 = 111
	GracefulReleasePeriod                                            uint16 = 112
	PDNType                                                          uint16 = 113
	FailedRuleID                                                     uint16 = 114
	TimeQuotaMechanism                                               uint16 = 115
	UserPlaneIPResourceInformation                                   uint16 = 116
	UserPlaneInactivityTimer                                         uint16 = 117
	AggregatedURRs                                                   uint16 = 118
	Multiplier                                                       uint16 = 119
	AggregatedURRID                                                  uint16 = 120
	SubsequentVolumeQuota                                            uint16 = 121
	SubsequentTimeQuota                                              uint16 = 122
	RQI                                                              uint16 = 123
	QFI                                                              uint16 = 124
	QueryURRReference                                                uint16 = 125
	AdditionalUsageReportsInformation                                uint16 = 126
	CreateTrafficEndpoint                                            uint16 = 127
	CreatedTrafficEndpoint                                           uint16 = 128
	UpdateTrafficEndpoint                                            uint16 = 129
	RemoveTrafficEndpoint                                            uint16 = 130
	TrafficEndpointID                                                uint16 = 131
	EthernetPacketFilter                                             uint16 = 132
	MACAddress                                                       uint16 = 133
	CTAG                                                             uint16 = 134
	STAG                                                             uint16 = 135
	Ethertype                                                        uint16 = 136
	Proxying                                                         uint16 = 137
	EthernetFilterID                                                 uint16 = 138
	EthernetFilterProperties                                         uint16 = 139
	SuggestedBufferingPacketsCount                                   uint16 = 140
	UserID                                                           uint16 = 141
	EthernetPDUSessionInformation                                    uint16 = 142
	EthernetTrafficInformation                                       uint16 = 143
	MACAddressesDetected                                             uint16 = 144
	MACAddressesRemoved                                              uint16 = 145
	EthernetInactivityTimer                                          uint16 = 146
	AdditionalMonitoringTime                                         uint16 = 147
	EventQuota                                                       uint16 = 148
	EventThreshold                                                   uint16 = 149
	SubsequentEventQuota                                             uint16 = 150
	SubsequentEventThreshold                                         uint16 = 151
	TraceInformation                                                 uint16 = 152
	FramedRoute                                                      uint16 = 153
	FramedRouting                                                    uint16 = 154
	FramedIPv6Route                                                  uint16 = 155
	EventTimeStamp                                                   uint16 = 156
	AveragingWindow                                                  uint16 = 157
	PagingPolicyIndicator                                            uint16 = 158
	APNDNN                                                           uint16 = 159
	TGPPInterfaceType                                                uint16 = 160
	PFCPSRReqFlags                                                   uint16 = 161
	PFCPAUReqFlags                                                   uint16 = 162
	ActivationTime                                                   uint16 = 163
	DeactivationTime                                                 uint16 = 164
	CreateMAR                                                        uint16 = 165
	TGPPAccessForwardingActionInformation                            uint16 = 166
	NonTGPPAccessForwardingActionInformation                         uint16 = 167
	RemoveMAR                                                        uint16 = 168
	UpdateMAR                                                        uint16 = 169
	MARID                                                            uint16 = 170
	SteeringFunctionality                                            uint16 = 171
	SteeringMode                                                     uint16 = 172
	Weight                                                           uint16 = 173
	Priority                                                         uint16 = 174
	UpdateTGPPAccessForwardingActionInformation                      uint16 = 175
	UpdateNonTGPPAccessForwardingActionInformation                   uint16 = 176
	UEIPAddressPoolIdentity                                          uint16 = 177
	AlternativeSMFIPAddress                                          uint16 = 178
	PacketReplicationAndDetectionCarryOnInformation                  uint16 = 179
	SMFSetID                                                         uint16 = 180
	QuotaValidityTime                                                uint16 = 181
	NumberOfReports                                                  uint16 = 182
	PFCPSessionRetentionInformation                                  uint16 = 183
	PFCPASRspFlags                                                   uint16 = 184
	CPPFCPEntityIPAddress                                            uint16 = 185
	PFCPSEReqFlags                                                   uint16 = 186
	UserPlanePathRecoveryReport                                      uint16 = 187
	IPMulticastAddressingInfo                                        uint16 = 188
	JoinIPMulticastInformationWithinUsageReport                      uint16 = 189
	LeaveIPMulticastInformationWithinUsageReport                     uint16 = 190
	IPMulticastAddress                                               uint16 = 191
	SourceIPAddress                                                  uint16 = 192
	PacketRateStatus                                                 uint16 = 193
	CreateBridgeInfoForTSC                                           uint16 = 194
	CreatedBridgeInfoForTSC                                          uint16 = 195
	DSTTPortNumber                                                   uint16 = 196
	NWTTPortNumber                                                   uint16 = 197
	TSNBridgeID                                                      uint16 = 198
	TSCManagementInformationWithinSessionModificationRequest         uint16 = 199
	TSCManagementInformationWithinSessionModificationResponse        uint16 = 200
	TSCManagementInformationWithinSessionReportRequest               uint16 = 201
	PortManagementInformationForTSCWithinSessionModificationRequest  uint16 = 199 // Deprecated
	PortManagementInformationForTSCWithinSessionModificationResponse uint16 = 200 // Deprecated
	PortManagementInformationForTSCWithinSessionReportRequest        uint16 = 201 // Deprecated
	PortManagementInformationContainer                               uint16 = 202
	ClockDriftControlInformation                                     uint16 = 203
	RequestedClockDriftInformation                                   uint16 = 204
	ClockDriftReport                                                 uint16 = 205
	TSNTimeDomainNumber                                              uint16 = 206
	TimeOffsetThreshold                                              uint16 = 207
	CumulativeRateRatioThreshold                                     uint16 = 208
	TimeOffsetMeasurement                                            uint16 = 209
	CumulativeRateRatioMeasurement                                   uint16 = 210
	RemoveSRR                                                        uint16 = 211
	CreateSRR                                                        uint16 = 212
	UpdateSRR                                                        uint16 = 213
	SessionReport                                                    uint16 = 214
	SRRID                                                            uint16 = 215
	AccessAvailabilityControlInformation                             uint16 = 216
	RequestedAccessAvailabilityInformation                           uint16 = 217
	AccessAvailabilityReport                                         uint16 = 218
	AccessAvailabilityInformation                                    uint16 = 219
	ProvideATSSSControlInformation                                   uint16 = 220
	ATSSSControlParameters                                           uint16 = 221
	MPTCPControlInformation                                          uint16 = 222
	ATSSSLLControlInformation                                        uint16 = 223
	PMFControlInformation                                            uint16 = 224
	MPTCPParameters                                                  uint16 = 225
	ATSSSLLParameters                                                uint16 = 226
	PMFParameters                                                    uint16 = 227
	MPTCPAddressInformation                                          uint16 = 228
	UELinkSpecificIPAddress                                          uint16 = 229
	PMFAddressInformation                                            uint16 = 230
	ATSSSLLInformation                                               uint16 = 231
	DataNetworkAccessIdentifier                                      uint16 = 232
	UEIPAddressPoolInformation                                       uint16 = 233
	AveragePacketDelay                                               uint16 = 234
	MinimumPacketDelay                                               uint16 = 235
	MaximumPacketDelay                                               uint16 = 236
	QoSReportTrigger                                                 uint16 = 237
	GTPUPathQoSControlInformation                                    uint16 = 238
	GTPUPathQoSReport                                                uint16 = 239
	QoSInformationInGTPUPathQoSReport                                uint16 = 240
	GTPUPathInterfaceType                                            uint16 = 241
	QoSMonitoringPerQoSFlowControlInformation                        uint16 = 242
	RequestedQoSMonitoring                                           uint16 = 243
	ReportingFrequency                                               uint16 = 244
	PacketDelayThresholds                                            uint16 = 245
	MinimumWaitTime                                                  uint16 = 246
	QoSMonitoringReport                                              uint16 = 247
	QoSMonitoringMeasurement                                         uint16 = 248
	MTEDTControlInformation                                          uint16 = 249
	DLDataPacketsSize                                                uint16 = 250
	QERControlIndications                                            uint16 = 251
	PacketRateStatusReport                                           uint16 = 252
	NFInstanceID                                                     uint16 = 253
	EthernetContextInformation                                       uint16 = 254
	RedundantTransmissionParameters                                  uint16 = 255
	UpdatedPDR                                                       uint16 = 256
	SNSSAI                                                           uint16 = 257
	IPVersion                                                        uint16 = 258
	PFCPASReqFlags                                                   uint16 = 259
	DataStatus                                                       uint16 = 260
	ProvideRDSConfigurationInformation                               uint16 = 261
	RDSConfigurationInformation                                      uint16 = 262
	QueryPacketRateStatusWithinSessionModificationRequest            uint16 = 263
	PacketRateStatusReportWithinSessionModificationResponse          uint16 = 264
	MPTCPApplicableIndication                                        uint16 = 265
	BridgeManagementInformationContainer                             uint16 = 266
	UEIPAddressUsageInformation                                      uint16 = 267
	NumberOfUEIPAddresses                                            uint16 = 268
	ValidityTimer                                                    uint16 = 269
	RedundantTransmissionForwardingParameters                        uint16 = 270
	TransportDelayReporting                                          uint16 = 271
)

// IE represents an Information Element of PFCP messages.
type IE struct {
	Type         uint16
	Length       uint16
	EnterpriseID uint16
	Payload      []byte
	ChildIEs     []*IE
}

// New creates a new IE.
func New(itype uint16, data []byte) *IE {
	i := &IE{
		Type:    itype,
		Payload: data,
	}
	i.SetLength()

	return i
}

// NewVendorSpecificIE creates a new vendor-specific IE.
func NewVendorSpecificIE(itype, eid uint16, data []byte) *IE {
	i := &IE{
		Type:         itype,
		EnterpriseID: eid,
		Payload:      data,
	}
	i.SetLength()

	return i
}

// NewGroupedIE creates a new grouped IE.
func NewGroupedIE(itype uint16, ies ...*IE) *IE {
	return newGroupedIE(itype, 0, ies...)
}

// NewVendorSpecificGroupedIE creates a new grouped IE.
func NewVendorSpecificGroupedIE(itype, eid uint16, ies ...*IE) *IE {
	return newGroupedIE(itype, eid, ies...)
}

// NewUint8ValIE creates a new IE with uint8 value.
func NewUint8IE(itype uint16, v uint8) *IE {
	return newUint8ValIE(itype, v)
}

// NewUint16ValIE creates a new IE with uint16 value.
func NewUint16IE(itype uint16, v uint16) *IE {
	return newUint16ValIE(itype, v)
}

// NewUint32ValIE creates a new IE with uint32 value.
func NewUint32IE(itype uint16, v uint32) *IE {
	return newUint32ValIE(itype, v)
}

// NewUint64ValIE creates a new IE with uint64 value.
func NewUint64IE(itype uint16, v uint64) *IE {
	return newUint64ValIE(itype, v)
}

// NewStringIE creates a new IE with string value.
func NewStringIE(itype uint16, v string) *IE {
	return newStringIE(itype, v)
}

// NewFQDNIE creates a new IE with FQDN value.
func NewFQDNIE(itype uint16, v string) *IE {
	return newFQDNIE(itype, v)
}

// ValueAsUint8 returns the value of IE as uint8.
func (i *IE) ValueAsUint8() (uint8, error) {
	if i.IsGrouped() {
		return 0, &InvalidTypeError{Type: i.Type}
	}
	if len(i.Payload) < 1 {
		return 0, io.ErrUnexpectedEOF
	}

	return i.Payload[0], nil
}

// ValueAsUint16 returns the value of IE as uint16.
func (i *IE) ValueAsUint16() (uint16, error) {
	if i.IsGrouped() {
		return 0, &InvalidTypeError{Type: i.Type}
	}
	if len(i.Payload) < 2 {
		return 0, io.ErrUnexpectedEOF
	}

	return binary.BigEndian.Uint16(i.Payload[0:2]), nil
}

// ValueAsUint32 returns the value of IE as uint32.
func (i *IE) ValueAsUint32() (uint32, error) {
	if i.IsGrouped() {
		return 0, &InvalidTypeError{Type: i.Type}
	}
	if len(i.Payload) < 4 {
		return 0, io.ErrUnexpectedEOF
	}

	return binary.BigEndian.Uint32(i.Payload[0:4]), nil
}

// ValueAsUint64 returns the value of IE as uint64.
func (i *IE) ValueAsUint64() (uint64, error) {
	if i.IsGrouped() {
		return 0, &InvalidTypeError{Type: i.Type}
	}
	if len(i.Payload) < 8 {
		return 0, io.ErrUnexpectedEOF
	}

	return binary.BigEndian.Uint64(i.Payload[0:8]), nil
}

// ValueAsString returns the value of IE as string.
func (i *IE) ValueAsString() (string, error) {
	if i.IsGrouped() {
		return "", &InvalidTypeError{Type: i.Type}
	}

	return string(i.Payload), nil
}

// ValueAsFQDN returns the value of IE as string, decoded as FQDN.
func (i *IE) ValueAsFQDN() (string, error) {
	if i.IsGrouped() {
		return "", &InvalidTypeError{Type: i.Type}
	}

	return utils.DecodeFQDN(i.Payload), nil
}

// ValueAsGrouped returns the value of IE as grouped IE.
//
// This method returns the ChildIEs field if it is already parsed.
// Otherwise, it parses the Payload field and returns the result.
//
// It is recommended to access the ChildIEs field directly if you know the payload is
// already parsed and not modified. If you need to parse the payload anyway, use the
// `<IE-Name>()` method instead, which disregards the ChildIEs field.
//
// For vendor-specific IE, this method tries to parse as grouped IE. If it fails, it
// returns error.
func (i *IE) ValueAsGrouped() ([]*IE, error) {
	if !(i.IsGrouped() || i.IsVendorSpecific()) {
		return nil, &InvalidTypeError{Type: i.Type}
	}

	if len(i.ChildIEs) < 1 {
		return ParseMultiIEs(i.Payload)
	}
	return i.ChildIEs, nil
}

// valueAs3GPPTimestamp returns the value of IE as time.Time, in the format of
// timestamp IEs defined in 3GPP TS 29.244 as follows:
//
// "a UTC time. Octets 5 to 8 shall be encoded in the same format as the first four octets
// of the 64-bit timestamp format as defined in clause 6 of IETF RFC 5905 [12].
// NOTE: The encoding is defined as the time in seconds relative to 00:00:00 on 1 January 1900."
func (i *IE) valueAs3GPPTimestamp() (time.Time, error) {
	if i.IsGrouped() {
		return time.Time{}, &InvalidTypeError{Type: i.Type}
	}
	if len(i.Payload) < 4 {
		return time.Time{}, io.ErrUnexpectedEOF
	}

	return time.Unix(int64(binary.BigEndian.Uint32(i.Payload[0:4])-2208988800), 0), nil
}

// Parse parses b into IE.
//
// Note that this function uses the given bytes directly, so not safe to use
// the buffer after calling this function. When you use the buffer somewhere
// else, copy it before calling this function.
func Parse(b []byte) (*IE, error) {
	i := &IE{}
	if err := i.UnmarshalBinary(b); err != nil {
		return nil, err
	}
	return i, nil
}

// ParseMultiIEs decodes multiple IEs at a time.
// This is easy and useful but slower than decoding one by one.
// When you don't know the number of IEs, this is the only way to decode them.
// See benchmarks in diameter_test.go for the detail.
//
// Note that this function uses the given bytes directly, so not safe to use
// the buffer after calling this function. When you use the buffer somewhere
// else, copy it before calling this function.
func ParseMultiIEs(b []byte) ([]*IE, error) {
	var ies []*IE
	for {
		if len(b) == 0 {
			break
		}

		i, err := Parse(b)
		if err != nil {
			return nil, err
		}
		ies = append(ies, i)
		b = b[i.MarshalLen():]
	}
	return ies, nil
}

// UnmarshalBinary parses b into IE.
func (i *IE) UnmarshalBinary(b []byte) error {
	l := len(b)
	if l < 4 {
		return io.ErrUnexpectedEOF
	}

	i.Type = binary.BigEndian.Uint16(b[0:2])
	i.Length = binary.BigEndian.Uint16(b[2:4])

	offset := 4
	end := int(i.Length)
	if i.IsVendorSpecific() {
		if l < 6 {
			return io.ErrUnexpectedEOF
		}
		if end < 2 {
			return ErrInvalidLength
		}

		i.EnterpriseID = binary.BigEndian.Uint16(b[4:6])
		offset += 2
		end -= 2
	}

	if l <= offset {
		return nil
	}

	if l < offset+end {
		return io.ErrUnexpectedEOF
	}
	i.Payload = b[offset : offset+end]

	if i.IsGrouped() {
		var err error
		i.ChildIEs, err = ParseMultiIEs(i.Payload)
		if err != nil {
			return err
		}
	}

	return nil
}

// Marshal returns the byte sequence generated from an IE instance.
func (i *IE) Marshal() ([]byte, error) {
	b := make([]byte, i.MarshalLen())
	if err := i.MarshalTo(b); err != nil {
		return nil, err
	}
	return b, nil
}

// MarshalTo puts the byte sequence in the byte array given as b.
func (i *IE) MarshalTo(b []byte) error {
	l := len(b)
	if l < 4 {
		return ErrInvalidLength
	}

	binary.BigEndian.PutUint16(b[:2], i.Type)
	binary.BigEndian.PutUint16(b[2:4], i.Length)

	offset := 4
	if i.IsVendorSpecific() && l >= 6 {
		binary.BigEndian.PutUint16(b[4:6], i.EnterpriseID)
		offset += 2
	}

	if i.IsGrouped() {
		for _, ie := range i.ChildIEs {
			if err := ie.MarshalTo(b[offset:]); err != nil {
				return err
			}
			offset += ie.MarshalLen()
		}
		return nil
	}

	copy(b[offset:i.MarshalLen()], i.Payload)
	return nil
}

// MarshalLen returns field length in integer.
func (i *IE) MarshalLen() int {
	l := 4
	if i.IsVendorSpecific() {
		l += 2
	}

	if i.IsGrouped() {
		for _, ie := range i.ChildIEs {
			l += ie.MarshalLen()
		}
		return l
	}

	return l + len(i.Payload)
}

// SetLength sets the length in Length field.
func (i *IE) SetLength() {
	l := 0

	if i.IsVendorSpecific() {
		l += 2
	}

	i.Length = uint16(l + len(i.Payload))
}

// IsVendorSpecific reports whether an IE is vendor-specific or defined by 3gpp.
func (i *IE) IsVendorSpecific() bool {
	// Spef: TS 29.244 8.1.1 Information Element Format
	// If the Bit 8 of Octet 1 is not set, this indicates that the IE is defined by 3GPP
	// and the EnterpriseID is absent. If Bit 8 of Octet 1 is set, this indicates that the
	// IE is defined by a vendor and the Enterprise ID is present identified by the Enterprise ID.
	return i.Type&0x8000 != 0
}

func newUint8ValIE(t uint16, v uint8) *IE {
	return New(t, []byte{v})
}

func newUint16ValIE(t uint16, v uint16) *IE {
	i := New(t, make([]byte, 2))
	binary.BigEndian.PutUint16(i.Payload, v)
	return i
}

func newUint32ValIE(t uint16, v uint32) *IE {
	i := New(t, make([]byte, 4))
	binary.BigEndian.PutUint32(i.Payload, v)
	return i
}

func newUint64ValIE(t uint16, v uint64) *IE {
	i := New(t, make([]byte, 8))
	binary.BigEndian.PutUint64(i.Payload, v)
	return i
}

func newStringIE(t uint16, v string) *IE {
	return New(t, []byte(v))
}

func newFQDNIE(t uint16, v string) *IE {
	return New(t, utils.EncodeFQDN(v))
}

func newGroupedIE(itype, eid uint16, ies ...*IE) *IE {
	i := NewVendorSpecificIE(itype, eid, make([]byte, 0))

	for _, ie := range ies {
		if ie == nil {
			continue
		}

		i.ChildIEs = append(i.ChildIEs, ie)

		serialized, err := ie.Marshal()
		if err != nil {
			logger.Logf("newGroupedIE() failed to marshal an IE(Type=%d): %v", ie.Type, err)
			return nil
		}
		i.Payload = append(i.Payload, serialized...)
	}

	i.SetLength()

	return i
}