First Commit of Voltha-Go-Controller from Radisys

Change-Id: I8e2e908e7ab09a4fe3d86849da18b6d69dcf4ab0
diff --git a/internal/pkg/controller/changeevent.go b/internal/pkg/controller/changeevent.go
new file mode 100644
index 0000000..95f6b07
--- /dev/null
+++ b/internal/pkg/controller/changeevent.go
@@ -0,0 +1,92 @@
+/*
+* Copyright 2022-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 controller
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/opencord/voltha-lib-go/v7/pkg/log"
+	ofp "github.com/opencord/voltha-protos/v5/go/openflow_13"
+)
+
+// ChangeEventTask structure
+type ChangeEventTask struct {
+	taskID    uint8
+	ctx       context.Context
+	event     *ofp.ChangeEvent
+	device    *Device
+	timestamp string
+}
+
+// NewChangeEventTask is constructor for ChangeEventTask
+func NewChangeEventTask(ctx context.Context, event *ofp.ChangeEvent, device *Device) *ChangeEventTask {
+	var cet ChangeEventTask
+	cet.device = device
+	cet.event = event
+	cet.ctx = ctx
+	tstamp := (time.Now()).Format(time.RFC3339Nano)
+	cet.timestamp = tstamp
+	return &cet
+}
+
+// Name returns the name of the task
+func (cet *ChangeEventTask) Name() string {
+	return "Change Event Task"
+}
+
+// TaskID to return task id of the task
+func (cet *ChangeEventTask) TaskID() uint8 {
+	return cet.taskID
+}
+
+// Timestamp to return timestamp for the task
+func (cet *ChangeEventTask) Timestamp() string {
+	return cet.timestamp
+}
+
+// Stop to stop the task
+func (cet *ChangeEventTask) Stop() {
+}
+
+// Start to start the Change event task
+func (cet *ChangeEventTask) Start(ctx context.Context, taskID uint8) error {
+	cet.taskID = taskID
+	cet.ctx = ctx
+
+	if status, ok := cet.event.Event.(*ofp.ChangeEvent_PortStatus); ok {
+		portNo := status.PortStatus.Desc.PortNo
+		portName := status.PortStatus.Desc.Name
+		state := status.PortStatus.Desc.State
+		logger.Infow(ctx, "Process Port Change Event", log.Fields{"Port No": portNo, "Port Name": portName, "State": state, "Reason": status.PortStatus.Reason})
+		if status.PortStatus.Reason == ofp.OfpPortReason_OFPPR_ADD {
+			_ = cet.device.AddPort(portNo, portName)
+			if state == uint32(ofp.OfpPortState_OFPPS_LIVE) {
+				cet.device.ProcessPortState(portNo, state)
+			}
+		} else if status.PortStatus.Reason == ofp.OfpPortReason_OFPPR_DELETE {
+			if err := cet.device.DelPort(portNo); err != nil {
+				logger.Warnw(ctx, "DelPort Failed", log.Fields{"Port No": portNo, "Error": err})
+			}
+		} else if status.PortStatus.Reason == ofp.OfpPortReason_OFPPR_MODIFY {
+			cet.device.ProcessPortUpdate(portName, portNo, state)
+		}
+		logger.Infow(ctx, "Processed Port Change Event", log.Fields{"Port No": portNo, "Port Name": portName, "State": state, "Reason": status.PortStatus.Reason})
+		return nil
+	}
+	return errors.New("Invalid message received")
+}