[gtpv2] Easier IE handling

gtpv2/ie/ambr.go

@@ -11,9 +11,6 @@ import (
 
 // NewAggregateMaximumBitRate creates a new AggregateMaximumBitRate IE.
 func NewAggregateMaximumBitRate(up, down uint32) *IE {
-	// this is more efficient but removed for consistency with other structured IEs.
-	// return newUint64ValIE(AggregateMaximumBitRate, (uint64(up)<<32 | uint64(down)))
-
 	v := NewAggregateMaximumBitRateFields(up, down)
 	b, err := v.Marshal()
 	if err != nil {

gtpv2/ie/apn-restriction.go

@@ -4,11 +4,9 @@
 
 package ie
 
-import "io"
-
 // NewAPNRestriction creates a new APNRestriction IE.
 func NewAPNRestriction(restriction uint8) *IE {
-	return newUint8ValIE(APNRestriction, restriction)
+	return NewUint8IE(APNRestriction, restriction)
 }
 
 // APNRestriction returns APNRestriction in uint8 if the type of IE matches.
@@ -17,11 +15,7 @@ func (i *IE) APNRestriction() (uint8, error) {
 		return 0, &InvalidTypeError{Type: i.Type}
 	}
 
-	if len(i.Payload) < 1 {
-		return 0, io.ErrUnexpectedEOF
-	}
-
-	return i.Payload[0], nil
+	return i.ValueAsUint8()
 }
 
 // MustAPNRestriction returns APNRestriction in uint8, ignoring errors.
@@ -30,3 +24,8 @@ func (i *IE) MustAPNRestriction() uint8 {
 	v, _ := i.APNRestriction()
 	return v
 }
+
+// RestrictionType returns RestrictionType in uint8 if the type of IE matches.
+func (i *IE) RestrictionType() (uint8, error) {
+	return i.APNRestriction()
+}

gtpv2/ie/apn.go

@@ -4,48 +4,17 @@
 
 package ie
 
-import (
-	"strings"
-)
-
 // NewAccessPointName creates a new AccessPointName IE.
 func NewAccessPointName(apn string) *IE {
-	i := New(AccessPointName, 0x00, make([]byte, len(apn)+1))
-	var offset = 0
-	for _, label := range strings.Split(apn, ".") {
-		l := len(label)
-		i.Payload[offset] = uint8(l)
-		copy(i.Payload[offset+1:], label)
-		offset += l + 1
-	}
-
-	return i
+	return NewFQDNIE(AccessPointName, apn)
 }
 
 // AccessPointName returns AccessPointName in string if the type of IE matches.
 func (i *IE) AccessPointName() (string, error) {
 	if i.Type != AccessPointName {
 		return "", &InvalidTypeError{Type: i.Type}
 	}
-
-	var (
-		apn    []string
-		offset int
-	)
-	max := len(i.Payload)
-	for {
-		if offset >= max {
-			break
-		}
-		l := int(i.Payload[offset])
-		if offset+l+1 > max {
-			break
-		}
-		apn = append(apn, string(i.Payload[offset+1:offset+l+1]))
-		offset += l + 1
-	}
-
-	return strings.Join(apn, "."), nil
+	return i.ValueAsFQDN()
 }
 
 // MustAccessPointName returns AccessPointName in string, ignoring errors.

gtpv2/ie/arp.go

@@ -4,24 +4,19 @@
 
 package ie
 
-import "io"
-
 // NewAllocationRetensionPriority creates a new AllocationRetensionPriority IE.
 func NewAllocationRetensionPriority(pci, pl, pvi uint8) *IE {
 	i := New(AllocationRetensionPriority, 0x00, make([]byte, 1))
 	i.Payload[0] |= (pci << 6 & 0x40) | (pl << 2 & 0x3c) | (pvi & 0x01)
 	return i
 }
 
+// AllocationRetensionPriority returns AllocationRetensionPriority in uint8 if the type of IE matches.
 func (i *IE) AllocationRetensionPriority() (uint8, error) {
 	if i.Type != AllocationRetensionPriority {
 		return 0, &InvalidTypeError{Type: i.Type}
 	}
-	if len(i.Payload) < 1 {
-		return 0, io.ErrUnexpectedEOF
-	}
-
-	return i.Payload[0], nil
+	return i.ValueAsUint8()
 }
 
 // HasPVI reports whether an IE has PVI bit.

gtpv2/ie/bearer-context.go

@@ -8,13 +8,7 @@ import "io"
 
 // NewBearerContext creates a new BearerContext IE.
 func NewBearerContext(ies ...*IE) *IE {
-	var omitted []*IE
-	for _, ie := range ies {
-		if ie != nil {
-			omitted = append(omitted, ie)
-		}
-	}
-	return newGroupedIE(BearerContext, omitted...)
+	return NewGroupedIE(BearerContext, ies...)
 }
 
 // NewBearerContextWithinCreateBearerRequest creates a new BearerContext used within CreateBearerRequest.

gtpv2/ie/bearer-flags.go

@@ -4,11 +4,6 @@
 
 package ie
 
-import (
-	"fmt"
-	"io"
-)
-
 // NewBearerFlags creates a new BearerFlags IE.
 func NewBearerFlags(asi, vInd, vb, ppc uint8) *IE {
 	i := New(BearerFlags, 0x00, make([]byte, 1))
@@ -20,15 +15,11 @@ func NewBearerFlags(asi, vInd, vb, ppc uint8) *IE {
 func (i *IE) BearerFlags() (uint8, error) {
 	switch i.Type {
 	case BearerFlags:
-		if len(i.Payload) < 1 {
-			return 0, io.ErrUnexpectedEOF
-		}
-
-		return i.Payload[0], nil
+		return i.ValueAsUint8()
 	case BearerContext:
 		ies, err := i.BearerContext()
 		if err != nil {
-			return 0, fmt.Errorf("failed to retrieve BearerFlags: %w", err)
+			return 0, err
 		}
 
 		for _, child := range ies {
@@ -92,54 +83,38 @@ func (i *IE) HasASI() bool {
 // ActivityStatusIndicator reports whether the bearer context is preserved in
 // the CN without corresponding Radio Access Bearer established.
 func (i *IE) ActivityStatusIndicator() bool {
-	if len(i.Payload) < 1 {
-		return false
-	}
-	switch i.Type {
-	case BearerFlags:
-		return i.Payload[0]&0x08 == 1
-	default:
+	v, err := i.BearerFlags()
+	if err != nil {
 		return false
 	}
+	return v&0x08 == 1
 }
 
 // VSRVCC reports whether this bearer is an IMS video bearer and is candidate
 // for PS-to-CS vSRVCC handover.
 func (i *IE) VSRVCC() bool {
-	if len(i.Payload) < 1 {
-		return false
-	}
-	switch i.Type {
-	case BearerFlags:
-		return i.Payload[0]&0x04 == 1
-	default:
+	v, err := i.BearerFlags()
+	if err != nil {
 		return false
 	}
+	return v&0x04 == 1
 }
 
 // VoiceBearer reports whether a voice bearer when doing PS-to-CS (v)SRVCC handover.
 func (i *IE) VoiceBearer() bool {
-	if len(i.Payload) < 1 {
-		return false
-	}
-	switch i.Type {
-	case BearerFlags:
-		return i.Payload[0]&0x02 == 1
-	default:
+	v, err := i.BearerFlags()
+	if err != nil {
 		return false
 	}
+	return v&0x02 == 1
 }
 
 // ProhibitPayloadCompression reports whether an SGSN should attempt to
 // compress the payload of user data when the users asks for it to be compressed.
 func (i *IE) ProhibitPayloadCompression() bool {
-	if len(i.Payload) < 1 {
-		return false
-	}
-	switch i.Type {
-	case BearerFlags:
-		return i.Payload[0]&0x01 == 1
-	default:
+	v, err := i.BearerFlags()
+	if err != nil {
 		return false
 	}
+	return v&0x01 == 1
 }

gtpv2/ie/bearer-qos.go

@@ -134,10 +134,7 @@ func (i *IE) QCILabel() (uint8, error) {
 		}
 		return i.Payload[1], nil
 	case FlowQoS:
-		if len(i.Payload) < 1 {
-			return 0, io.ErrUnexpectedEOF
-		}
-		return i.Payload[0], nil
+		return i.ValueAsUint8()
 	default:
 		return 0, &InvalidTypeError{Type: i.Type}
 	}

gtpv2/ie/cause.go

@@ -28,11 +28,7 @@ func NewCause(cause uint8, pce, bce, cs uint8, offendingIE *IE) *IE {
 func (i *IE) Cause() (uint8, error) {
 	switch i.Type {
 	case Cause:
-		if len(i.Payload) < 1 {
-			return 0, io.ErrUnexpectedEOF
-		}
-
-		return i.Payload[0], nil
+		return i.ValueAsUint8()
 	case BearerContext:
 		ies, err := i.BearerContext()
 		if err != nil {

gtpv2/ie/charging-characteristics.go

@@ -4,26 +4,17 @@
 
 package ie
 
-import (
-	"encoding/binary"
-	"io"
-)
-
 // NewChargingCharacteristics creates a new ChargingCharacteristics IE.
 func NewChargingCharacteristics(chr uint16) *IE {
-	return newUint16ValIE(ChargingCharacteristics, chr)
+	return NewUint16IE(ChargingCharacteristics, chr)
 }
 
 // ChargingCharacteristics returns the ChargingCharacteristics value in uint16 if the type of IE matches.
 func (i *IE) ChargingCharacteristics() (uint16, error) {
 	if i.Type != ChargingCharacteristics {
 		return 0, &InvalidTypeError{Type: i.Type}
 	}
-	if len(i.Payload) < 2 {
-		return 0, io.ErrUnexpectedEOF
-	}
-
-	return binary.BigEndian.Uint16(i.Payload), nil
+	return i.ValueAsUint16()
 }
 
 // MustChargingCharacteristics returns ChargingCharacteristics in uint16, ignoring errors.

gtpv2/ie/charging-id.go

@@ -4,30 +4,20 @@
 
 package ie
 
-import (
-	"encoding/binary"
-	"fmt"
-	"io"
-)
-
 // NewChargingID creates a new ChargingID IE.
 func NewChargingID(id uint32) *IE {
-	return newUint32ValIE(ChargingID, id)
+	return NewUint32IE(ChargingID, id)
 }
 
 // ChargingID returns the ChargingID value in uint32 if the type of IE matches.
 func (i *IE) ChargingID() (uint32, error) {
 	switch i.Type {
 	case ChargingID:
-		if len(i.Payload) < 4 {
-			return 0, io.ErrUnexpectedEOF
-		}
-
-		return binary.BigEndian.Uint32(i.Payload[:4]), nil
+		return i.ValueAsUint32()
 	case BearerContext:
 		ies, err := i.BearerContext()
 		if err != nil {
-			return 0, fmt.Errorf("failed to retrieve ChargingID: %w", err)
+			return 0, err
 		}
 
 		for _, child := range ies {

gtpv2/ie/cmi.go

@@ -8,23 +8,19 @@ import "io"
 
 // NewCSGMembershipIndication creates a new CSGMembershipIndication IE.
 func NewCSGMembershipIndication(cmi uint8) *IE {
-	return newUint8ValIE(CSGMembershipIndication, cmi)
+	return NewUint8IE(CSGMembershipIndication, cmi)
 }
 
 // CMI returns CMI in uint8 if the type of IE matches.
 func (i *IE) CMI() (uint8, error) {
-	if len(i.Payload) < 1 {
-		return 0, io.ErrUnexpectedEOF
-	}
-
 	switch i.Type {
 	case CSGMembershipIndication:
-		return i.Payload[0] & 0x01, nil
+		return i.ValueAsUint8()
 	case UserCSGInformation:
 		if len(i.Payload) < 8 {
 			return 0, io.ErrUnexpectedEOF
 		}
-		return i.Payload[7] & 0x01, nil
+		return i.Payload[7], nil
 	default:
 		return 0, &InvalidTypeError{Type: i.Type}
 	}

gtpv2/ie/csg-id.go

@@ -11,18 +11,14 @@ import (
 
 // NewCSGID creates a new CSGID IE.
 func NewCSGID(id uint32) *IE {
-	return newUint32ValIE(CSGID, id&0x7ffffff)
+	return NewUint32IE(CSGID, id&0x7ffffff)
 }
 
 // CSGID returns CSGID in uint32 if the type of IE matches.
 func (i *IE) CSGID() (uint32, error) {
-	if len(i.Payload) < 4 {
-		return 0, io.ErrUnexpectedEOF
-	}
-
 	switch i.Type {
 	case CSGID:
-		return binary.BigEndian.Uint32(i.Payload[0:4]) & 0x7ffffff, nil
+		return i.ValueAsUint32()
 	case UserCSGInformation:
 		if len(i.Payload) < 7 {
 			return 0, io.ErrUnexpectedEOF

gtpv2/ie/delay-value.go

@@ -11,10 +11,20 @@ import (
 
 // NewDelayValue creates a new DelayValue IE.
 func NewDelayValue(delay time.Duration) *IE {
-	return newUint8ValIE(DelayValue, uint8(delay.Seconds()*1000/50))
+	return NewUint8IE(DelayValue, uint8(delay.Seconds()*1000/50))
+}
+
+// NewDelayValueRaw creates a new DelayValue IE from a uint8 value.
+//
+// The value should be in multiples of 50ms or zero.
+func NewDelayValueRaw(delay uint8) *IE {
+	return NewUint8IE(DelayValue, delay)
 }
 
 // DelayValue returns DelayValue in time.Duration if the type of IE matches.
+//
+// The returned value is in time.Duration. To get the value in multiples of 50ms,
+// use ValueAsUint8 or access Payload field directly instead.
 func (i *IE) DelayValue() (time.Duration, error) {
 	if i.Type != DelayValue {
 		return 0, &InvalidTypeError{Type: i.Type}