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

Change-Id: I6c5e1a167216ad9b51e9da89460e9909465ae1bc
diff --git a/get.go b/get.go
new file mode 100644
index 0000000..0214907
--- /dev/null
+++ b/get.go
@@ -0,0 +1,380 @@
+/*
+ * 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 GetRequest struct {
+	MeBasePacket
+	AttributeMask uint16
+}
+
+func (omci *GetRequest) String() string {
+	return fmt.Sprintf("%v, Mask: %#x",
+		omci.MeBasePacket.String(), omci.AttributeMask)
+}
+
+// LayerType returns LayerTypeGetRequest
+func (omci *GetRequest) LayerType() gopacket.LayerType {
+	return LayerTypeGetRequest
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode
+func (omci *GetRequest) CanDecode() gopacket.LayerClass {
+	return LayerTypeGetRequest
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (omci *GetRequest) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypePayload
+}
+
+// DecodeFromBytes decodes the given bytes of a Get Request into this layer
+func (omci *GetRequest) DecodeFromBytes(data []byte, p gopacket.PacketBuilder) error {
+	// Common ClassID/EntityID decode in msgBase
+	var hdrSize int
+	if omci.Extended {
+		hdrSize = 6 + 2
+	} else {
+		hdrSize = 4 + 2
+	}
+	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 Get
+	if !me.SupportsMsgType(meDefinition, me.Get) {
+		return me.NewProcessingError("managed entity does not support Get Message-Type")
+	}
+	if omci.Extended {
+		if len(data) < 8 {
+			p.SetTruncated()
+			return errors.New("frame too small")
+		}
+		omci.AttributeMask = binary.BigEndian.Uint16(data[6:])
+	} else {
+		omci.AttributeMask = binary.BigEndian.Uint16(data[4:])
+	}
+	return nil
+}
+
+func decodeGetRequest(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetRequest{}
+	omci.MsgLayerType = LayerTypeGetRequest
+	return decodingLayerDecoder(omci, data, p)
+}
+
+func decodeGetRequestExtended(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetRequest{}
+	omci.MsgLayerType = LayerTypeGetRequest
+	omci.Extended = true
+	return decodingLayerDecoder(omci, data, p)
+}
+
+// SerializeTo provides serialization of an Get Request message
+func (omci *GetRequest) 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 Set
+	if !me.SupportsMsgType(meDefinition, me.Get) {
+		return me.NewProcessingError("managed entity does not support Get Message-Type")
+	}
+	maskOffset := 0
+	if omci.Extended {
+		maskOffset = 2
+	}
+	bytes, err := b.AppendBytes(2 + maskOffset)
+	if err != nil {
+		return err
+	}
+	if omci.Extended {
+		binary.BigEndian.PutUint16(bytes, uint16(2))
+	}
+	binary.BigEndian.PutUint16(bytes[maskOffset:], omci.AttributeMask)
+	return nil
+}
+
+type GetResponse struct {
+	MeBasePacket
+	Result                   me.Results
+	AttributeMask            uint16
+	Attributes               me.AttributeValueMap
+	UnsupportedAttributeMask uint16
+	FailedAttributeMask      uint16
+}
+
+func (omci *GetResponse) String() string {
+	return fmt.Sprintf("%v, Result: %d (%v), Mask: %#x, Unsupported: %#x, Failed: %#x, attributes: %v",
+		omci.MeBasePacket.String(), omci.Result, omci.Result, omci.AttributeMask,
+		omci.UnsupportedAttributeMask, omci.FailedAttributeMask, omci.Attributes)
+}
+
+// LayerType returns LayerTypeGetResponse
+func (omci *GetResponse) LayerType() gopacket.LayerType {
+	return LayerTypeGetResponse
+}
+
+// CanDecode returns the set of layer types that this DecodingLayer can decode
+func (omci *GetResponse) CanDecode() gopacket.LayerClass {
+	return LayerTypeGetResponse
+}
+
+// NextLayerType returns the layer type contained by this DecodingLayer.
+func (omci *GetResponse) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypePayload
+}
+
+// DecodeFromBytes decodes the given bytes of a Get Response into this layer
+func (omci *GetResponse) DecodeFromBytes(data []byte, p gopacket.PacketBuilder) error {
+	// Common ClassID/EntityID decode in msgBase
+	err := omci.MeBasePacket.DecodeFromBytes(data, p, 4+3)
+	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.Get) {
+		return me.NewProcessingError("managed entity does not support Get Message-Type")
+	}
+	if omci.Extended {
+		if len(data) < 13 {
+			p.SetTruncated()
+			return errors.New("frame too small")
+		}
+		omci.Result = me.Results(data[6])
+		omci.AttributeMask = binary.BigEndian.Uint16(data[7:])
+
+		// If Attribute failed or Unknown, decode optional attribute mask
+		if omci.Result == me.AttributeFailure {
+			omci.UnsupportedAttributeMask = binary.BigEndian.Uint16(data[9:])
+			omci.FailedAttributeMask = binary.BigEndian.Uint16(data[11:])
+		}
+	} else {
+		omci.Result = me.Results(data[4])
+		omci.AttributeMask = binary.BigEndian.Uint16(data[5:])
+
+		// If Attribute failed or Unknown, decode optional attribute mask
+		if omci.Result == me.AttributeFailure {
+			omci.UnsupportedAttributeMask = binary.BigEndian.Uint16(data[32:34])
+			omci.FailedAttributeMask = binary.BigEndian.Uint16(data[34:36])
+		}
+	}
+	// Attribute decode. Note that the ITU-T G.988 specification states that the
+	//                   Unsupported and Failed attribute masks are always present
+	//                   but only valid if the status code== 9.  However some XGS
+	//                   ONUs (T&W and Alpha, perhaps more) will use these last 4
+	//                   octets for data if the status code == 0.  So accommodate
+	//                   this behaviour in favor of greater interoperability.
+	firstOctet := 7
+	lastOctet := 36
+	if omci.Extended {
+		firstOctet = 13
+		lastOctet = len(data)
+	}
+
+	switch omci.Result {
+	case me.ProcessingError, me.NotSupported, me.UnknownEntity, me.UnknownInstance, me.DeviceBusy:
+		return nil // Done (do not try and decode attributes)
+
+	case me.AttributeFailure:
+		if !omci.Extended {
+			lastOctet = 32
+		}
+	}
+	omci.Attributes, err = meDefinition.DecodeAttributes(omci.AttributeMask,
+		data[firstOctet:lastOctet], p, byte(GetResponseType))
+	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
+	}
+	return errors.New("all Managed Entities have an EntityID attribute")
+}
+
+func decodeGetResponse(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetResponse{}
+	omci.MsgLayerType = LayerTypeGetResponse
+	return decodingLayerDecoder(omci, data, p)
+}
+
+func decodeGetResponseExtended(data []byte, p gopacket.PacketBuilder) error {
+	omci := &GetResponse{}
+	omci.MsgLayerType = LayerTypeGetResponse
+	omci.Extended = true
+	return decodingLayerDecoder(omci, data, p)
+}
+
+// SerializeTo provides serialization of an Get Response message
+func (omci *GetResponse) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	// Basic (common) OMCI Header is 8 octets, 10
+	if err := omci.MeBasePacket.SerializeTo(b); 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.Get) {
+		return me.NewProcessingError("managed entity does not support the Get Message-Type")
+	}
+	resultOffset := 0
+	attributeErrExtra := 0
+
+	if omci.Extended {
+		resultOffset = 2
+		attributeErrExtra = 4 // Attribute mask + attribute error masks
+	}
+	// Space for result + mask (both types) + (len & error masks if extended)
+	buffer, err := b.AppendBytes(3 + resultOffset + attributeErrExtra)
+	if err != nil {
+		return err
+	}
+	// Save result and initial mask. Other header fields updated after
+	// attribute copy
+	buffer[resultOffset] = byte(omci.Result)
+	binary.BigEndian.PutUint16(buffer[resultOffset+1:], omci.AttributeMask)
+
+	// Validate all attributes requested support read
+	for attrName := range omci.Attributes {
+		var attr *me.AttributeDefinition
+		attr, err = me.GetAttributeDefinitionByName(meDefinition.GetAttributeDefinitions(), attrName)
+		if err != nil {
+			return err
+		}
+		if attr.Index != 0 && (attr.Mask&omci.AttributeMask != 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:
+		if omci.Extended {
+			// Minimum length is 7 for extended an need to write error masks
+			binary.BigEndian.PutUint16(buffer, uint16(7))
+			binary.BigEndian.PutUint32(buffer[resultOffset+3:], 0)
+		}
+		break
+
+	case me.Success, me.AttributeFailure:
+		// TODO: Baseline only supported at this time)
+		var available int
+		if omci.Extended {
+			available = MaxExtendedLength - 18 - 4 // Less: header, mic
+		} else {
+			available = MaxBaselineLength - 11 - 4 - 8 // Less: header, failed attributes, length, mic
+		}
+		// Serialize to temporary buffer if we may need to reset values due to
+		// recoverable truncation errors
+		attributeBuffer := gopacket.NewSerializeBuffer()
+		var failedMask uint16
+		err, failedMask = meDefinition.SerializeAttributes(omci.Attributes, omci.AttributeMask,
+			attributeBuffer, byte(GetResponseType), available, opts.FixLengths)
+
+		if err != nil {
+			return err
+		}
+		if failedMask != 0 {
+			// Not all attributes would fit
+			omci.FailedAttributeMask |= failedMask
+			omci.AttributeMask &= ^failedMask
+			omci.Result = me.AttributeFailure
+
+			// Adjust already recorded values
+			buffer[resultOffset] = byte(omci.Result)
+			binary.BigEndian.PutUint16(buffer[resultOffset+1:], omci.AttributeMask)
+		}
+		if omci.Extended {
+			// Set length and any failure masks
+			binary.BigEndian.PutUint16(buffer, uint16(len(attributeBuffer.Bytes())+7))
+
+			if omci.Result == me.AttributeFailure {
+				binary.BigEndian.PutUint16(buffer[resultOffset+3:], omci.UnsupportedAttributeMask)
+				binary.BigEndian.PutUint16(buffer[resultOffset+5:], omci.FailedAttributeMask)
+			} else {
+				binary.BigEndian.PutUint32(buffer[resultOffset+3:], 0)
+			}
+		}
+		// Copy over attributes to the original serialization buffer
+		var newSpace []byte
+
+		newSpace, err = b.AppendBytes(len(attributeBuffer.Bytes()))
+		if err != nil {
+			return err
+		}
+		copy(newSpace, attributeBuffer.Bytes())
+
+		if !omci.Extended {
+			// Calculate space left. Max  - msgType header - OMCI trailer - spacedUsedSoFar
+			bytesLeft := MaxBaselineLength - 4 - 8 - len(b.Bytes())
+
+			var remainingBytes []byte
+			remainingBytes, err = b.AppendBytes(bytesLeft + 4)
+
+			if err != nil {
+				return me.NewMessageTruncatedError(err.Error())
+			}
+			copy(remainingBytes, lotsOfZeros[:])
+
+			if omci.Result == me.AttributeFailure {
+				binary.BigEndian.PutUint16(remainingBytes[bytesLeft-4:bytesLeft-2], omci.UnsupportedAttributeMask)
+				binary.BigEndian.PutUint16(remainingBytes[bytesLeft-2:bytesLeft], omci.FailedAttributeMask)
+			}
+		}
+	}
+	return nil
+}