VOL-4337: Code upgrade for 3/2020 G.988 support and remaining Extended Message Set support

Change-Id: I6c5e1a167216ad9b51e9da89460e9909465ae1bc
diff --git a/getnext.go b/getnext.go
new file mode 100644
index 0000000..1a79bdc
--- /dev/null
+++ b/getnext.go
@@ -0,0 +1,305 @@
+/*
+ * Copyright (c) 2018 - present.  Boling Consulting Solutions (bcsw.net)
+ * Copyright 2020-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package omci
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"github.com/google/gopacket"
+	me "github.com/opencord/omci-lib-go/generated"
+)
+
+type GetNextRequest struct {
+	MeBasePacket
+	AttributeMask  uint16
+	SequenceNumber uint16
+}
+
+func (omci *GetNextRequest) String() string {
+	return fmt.Sprintf("%v, Attribute Mask: %#x, Sequence Number: %v",
+		omci.MeBasePacket.String(), omci.AttributeMask, omci.SequenceNumber)
+}
+
+// LayerType returns LayerTypeGetNextRequest
+func (omci *GetNextRequest) LayerType() gopacket.LayerType {
+	return LayerTypeGetNextRequest
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode
+func (omci *GetNextRequest) CanDecode() gopacket.LayerClass {
+	return LayerTypeGetNextRequest
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (omci *GetNextRequest) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypePayload
+}
+
+// DecodeFromBytes decodes the given bytes of a Get Next Request into this layer
+func (omci *GetNextRequest) DecodeFromBytes(data []byte, p gopacket.PacketBuilder) error {
+	// Common ClassID/EntityID decode in msgBase
+	var hdrSize int
+	if omci.Extended {
+		//start here
+		hdrSize = 6 + 4
+	} else {
+		hdrSize = 4 + 4
+	}
+	err := omci.MeBasePacket.DecodeFromBytes(data, p, hdrSize)
+	if err != nil {
+		return err
+	}
+	meDefinition, omciErr := me.LoadManagedEntityDefinition(omci.EntityClass,
+		me.ParamData{EntityID: omci.EntityInstance})
+	if omciErr.StatusCode() != me.Success {
+		return omciErr.GetError()
+	}
+	// ME needs to support GetNext
+	if !me.SupportsMsgType(meDefinition, me.GetNext) {
+		return me.NewProcessingError("managed entity does not support Get Next Message-Type")
+	}
+	// Note: G.988 specifies that an error code of (3) should result if more
+	//       than one attribute is requested
+	// TODO: Return error.  Have flag to optionally allow it to be encoded
+	// TODO: Check that the attribute is a table attribute.  Issue warning or return error
+	omci.AttributeMask = binary.BigEndian.Uint16(data[hdrSize-4:])
+	omci.SequenceNumber = binary.BigEndian.Uint16(data[hdrSize-2:])
+	return nil
+}
+
+func decodeGetNextRequest(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetNextRequest{}
+	omci.MsgLayerType = LayerTypeGetNextRequest
+	return decodingLayerDecoder(omci, data, p)
+}
+
+func decodeGetNextRequestExtended(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetNextRequest{}
+	omci.MsgLayerType = LayerTypeGetNextRequest
+	omci.Extended = true
+	return decodingLayerDecoder(omci, data, p)
+}
+
+// SerializeTo provides serialization of an Get Next Message Type Request
+func (omci *GetNextRequest) SerializeTo(b gopacket.SerializeBuffer, _ gopacket.SerializeOptions) error {
+	// Basic (common) OMCI Header is 8 octets, 10
+	err := omci.MeBasePacket.SerializeTo(b)
+	if err != nil {
+		return err
+	}
+	meDefinition, omciErr := me.LoadManagedEntityDefinition(omci.EntityClass,
+		me.ParamData{EntityID: omci.EntityInstance})
+	if omciErr.StatusCode() != me.Success {
+		return omciErr.GetError()
+	}
+	// ME needs to support GetNext
+	if !me.SupportsMsgType(meDefinition, me.GetNext) {
+		return me.NewProcessingError("managed entity does not support Get Next Message-Type")
+	}
+	maskOffset := 0
+	if omci.Extended {
+		maskOffset = 2
+	}
+	bytes, err := b.AppendBytes(4 + maskOffset)
+	if err != nil {
+		return err
+	}
+	if omci.Extended {
+		binary.BigEndian.PutUint16(bytes, uint16(4))
+	}
+	binary.BigEndian.PutUint16(bytes[maskOffset:], omci.AttributeMask)
+	binary.BigEndian.PutUint16(bytes[maskOffset+2:], omci.SequenceNumber)
+	return nil
+}
+
+type GetNextResponse struct {
+	MeBasePacket
+	Result        me.Results
+	AttributeMask uint16
+	Attributes    me.AttributeValueMap
+}
+
+// SerializeTo provides serialization of an Get Next Message Type Response
+func (omci *GetNextResponse) String() string {
+	return fmt.Sprintf("%v, Result: %v, Attribute Mask: %#x, Attributes: %v",
+		omci.MeBasePacket.String(), omci.Result, omci.AttributeMask, omci.Attributes)
+}
+
+// LayerType returns LayerTypeGetNextResponse
+func (omci *GetNextResponse) LayerType() gopacket.LayerType {
+	return LayerTypeGetNextResponse
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode
+func (omci *GetNextResponse) CanDecode() gopacket.LayerClass {
+	return LayerTypeGetNextResponse
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (omci *GetNextResponse) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypePayload
+}
+
+// DecodeFromBytes decodes the given bytes of a Get Next Response into this layer
+func (omci *GetNextResponse) DecodeFromBytes(data []byte, p gopacket.PacketBuilder) error {
+	// Common ClassID/EntityID decode in msgBase
+	var hdrSize int
+	if omci.Extended {
+		//start here
+		hdrSize = 6 + 3
+	} else {
+		hdrSize = 4 + 3
+	}
+	err := omci.MeBasePacket.DecodeFromBytes(data, p, hdrSize)
+	if err != nil {
+		return err
+	}
+	meDefinition, omciErr := me.LoadManagedEntityDefinition(omci.EntityClass,
+		me.ParamData{EntityID: omci.EntityInstance})
+	if omciErr.StatusCode() != me.Success {
+		return omciErr.GetError()
+	}
+	// ME needs to support Set
+	if !me.SupportsMsgType(meDefinition, me.GetNext) {
+		return me.NewProcessingError("managed entity does not support Get Next Message-Type")
+	}
+	var offset int
+	if omci.Extended {
+		offset = 2
+	}
+	omci.Result = me.Results(data[4+offset])
+	if omci.Result > 6 {
+		msg := fmt.Sprintf("invalid get next results code: %v, must be 0..6", omci.Result)
+		return errors.New(msg)
+	}
+	omci.AttributeMask = binary.BigEndian.Uint16(data[4+offset+1:])
+
+	// Attribute decode
+	omci.Attributes, err = meDefinition.DecodeAttributes(omci.AttributeMask, data[4+offset+3:], p, byte(GetNextResponseType))
+	if err != nil {
+		return err
+	}
+	// Validate all attributes support read
+	for attrName := range omci.Attributes {
+		attr, err := me.GetAttributeDefinitionByName(meDefinition.GetAttributeDefinitions(), attrName)
+		if err != nil {
+			return err
+		}
+		if attr.Index != 0 && !me.SupportsAttributeAccess(*attr, me.Read) {
+			msg := fmt.Sprintf("attribute '%v' does not support read access", attrName)
+			return me.NewProcessingError(msg)
+		}
+	}
+	if eidDef, eidDefOK := meDefinition.GetAttributeDefinitions()[0]; eidDefOK {
+		omci.Attributes[eidDef.GetName()] = omci.EntityInstance
+		return nil
+	}
+	panic("All Managed Entities have an EntityID attribute")
+}
+
+func decodeGetNextResponse(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetNextResponse{}
+	omci.MsgLayerType = LayerTypeGetNextResponse
+	return decodingLayerDecoder(omci, data, p)
+}
+
+func decodeGetNextResponseExtended(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetNextResponse{}
+	omci.MsgLayerType = LayerTypeGetNextResponse
+	omci.Extended = true
+	return decodingLayerDecoder(omci, data, p)
+}
+
+// SerializeTo provides serialization of an Get Next Message Type Response
+func (omci *GetNextResponse) SerializeTo(b gopacket.SerializeBuffer, _ gopacket.SerializeOptions) error {
+	// Basic (common) OMCI Header is 8 octets, 10
+	err := omci.MeBasePacket.SerializeTo(b)
+	if err != nil {
+		return err
+	}
+	meDefinition, omciErr := me.LoadManagedEntityDefinition(omci.EntityClass,
+		me.ParamData{EntityID: omci.EntityInstance})
+	if omciErr.StatusCode() != me.Success {
+		return omciErr.GetError()
+	}
+	// ME needs to support Get
+	if !me.SupportsMsgType(meDefinition, me.GetNext) {
+		return me.NewProcessingError("managed entity does not support the Get Next Message-Type")
+	}
+	var offset int
+	if omci.Extended {
+		offset = 2
+	}
+	bytes, err := b.AppendBytes(offset + 3)
+	if err != nil {
+		return err
+	}
+	bytes[offset] = byte(omci.Result)
+	if omci.Result > 6 {
+		msg := fmt.Sprintf("invalid get next results code: %v, must be 0..6", omci.Result)
+		return errors.New(msg)
+	}
+	binary.BigEndian.PutUint16(bytes[offset+1:], omci.AttributeMask)
+
+	// Validate all attributes support read
+	for attrName := range omci.Attributes {
+		attr, err := me.GetAttributeDefinitionByName(meDefinition.GetAttributeDefinitions(), attrName)
+		if err != nil {
+			return err
+		}
+		if attr.Index != 0 && !me.SupportsAttributeAccess(*attr, me.Read) {
+			msg := fmt.Sprintf("attribute '%v' does not support read access", attrName)
+			return me.NewProcessingError(msg)
+		}
+	}
+	// Attribute serialization
+	switch omci.Result {
+	default:
+		break
+
+	case me.Success:
+		// TODO: Only Baseline supported at this time
+		if omci.Extended {
+			bytesAvailable := MaxExtendedLength - 13 - 4
+			attributeBuffer := gopacket.NewSerializeBuffer()
+			err, _ = meDefinition.SerializeAttributes(omci.Attributes, omci.AttributeMask,
+				attributeBuffer, byte(GetNextResponseType), bytesAvailable, false)
+			if err != nil {
+				return err
+			}
+			binary.BigEndian.PutUint16(bytes, uint16(len(attributeBuffer.Bytes())+3))
+			var newSpace []byte
+
+			newSpace, err = b.AppendBytes(len(attributeBuffer.Bytes()))
+			if err != nil {
+				return err
+			}
+			copy(newSpace, attributeBuffer.Bytes())
+		} else {
+			bytesAvailable := MaxBaselineLength - 11 - 8
+
+			err, _ = meDefinition.SerializeAttributes(omci.Attributes, omci.AttributeMask, b,
+				byte(GetNextResponseType), bytesAvailable, false)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}