internal/bbsim/responders/dhcp/dhcp.go - bbsim - Gitiles

 /*
  * Copyright 2018-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 dhcp

 import (
 	"errors"
 	"fmt"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"github.com/looplab/fsm"
 	bbsim "github.com/opencord/bbsim/internal/bbsim/types"
 	omci "github.com/opencord/omci-sim"
 	"github.com/opencord/voltha-protos/go/openolt"
 	log "github.com/sirupsen/logrus"
 	"net"
 	"reflect"
 )

 var dhcpLogger = log.WithFields(log.Fields{
 	"module": "DHCP",
 })

 var defaultParamsRequestList = []layers.DHCPOpt{
 	layers.DHCPOptSubnetMask,
 	layers.DHCPOptBroadcastAddr,
 	layers.DHCPOptTimeOffset,
 	layers.DHCPOptRouter,
 	layers.DHCPOptDomainName,
 	layers.DHCPOptDNS,
 	layers.DHCPOptDomainSearch,
 	layers.DHCPOptHostname,
 	layers.DHCPOptNetBIOSTCPNS,
 	layers.DHCPOptNetBIOSTCPScope,
 	layers.DHCPOptInterfaceMTU,
 	layers.DHCPOptClasslessStaticRoute,
 	layers.DHCPOptNTPServers,
 }

 func createDefaultDHCPReq(intfId uint32, onuId uint32) layers.DHCPv4 {
 	return layers.DHCPv4{
 		Operation:    layers.DHCPOpRequest,
 		HardwareType: layers.LinkTypeEthernet,
 		HardwareLen:  6,
 		HardwareOpts: 0,
 		Xid:          onuId,
 		ClientHWAddr: net.HardwareAddr{0x2e, 0x60, 0x70, 0x13, byte(intfId), byte(onuId)},
 	}
 }

 func createDefaultOpts() []layers.DHCPOption {
 	hostname := []byte("bbsim.onf.org")
 	opts := []layers.DHCPOption{}
 	opts = append(opts, layers.DHCPOption{
 		Type:   layers.DHCPOptHostname,
 		Data:   hostname,
 		Length: uint8(len(hostname)),
 	})

 	bytes := []byte{}
 	for _, option := range defaultParamsRequestList {
 		bytes = append(bytes, byte(option))
 	}

 	opts = append(opts, layers.DHCPOption{
 		Type:   layers.DHCPOptParamsRequest,
 		Data:   bytes,
 		Length: uint8(len(bytes)),
 	})
 	return opts
 }

 func createDHCPDisc(intfId uint32, onuId uint32) *layers.DHCPv4 {
 	dhcpLayer := createDefaultDHCPReq(intfId, onuId)
 	defaultOpts := createDefaultOpts()
 	dhcpLayer.Options = append([]layers.DHCPOption{layers.DHCPOption{
 		Type:   layers.DHCPOptMessageType,
 		Data:   []byte{byte(layers.DHCPMsgTypeDiscover)},
 		Length: 1,
 	}}, defaultOpts...)

 	return &dhcpLayer
 }

 func createDHCPReq(intfId uint32, onuId uint32) *layers.DHCPv4 {
 	dhcpLayer := createDefaultDHCPReq(intfId, onuId)
 	defaultOpts := createDefaultOpts()

 	dhcpLayer.Options = append(defaultOpts, layers.DHCPOption{
 		Type:   layers.DHCPOptMessageType,
 		Data:   []byte{byte(layers.DHCPMsgTypeRequest)},
 		Length: 1,
 	})

 	data := []byte{182, 21, 0, 128}
 	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
 		Type:   layers.DHCPOptServerID,
 		Data:   data,
 		Length: uint8(len(data)),
 	})

 	data = []byte{0xcd, 0x28, 0xcb, 0xcc, 0x00, 0x01, 0x00, 0x01,
 		0x23, 0xed, 0x11, 0xec, 0x4e, 0xfc, 0xcd, 0x28, 0xcb, 0xcc}
 	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
 		Type:   layers.DHCPOptClientID,
 		Data:   data,
 		Length: uint8(len(data)),
 	})

 	data = []byte{182, 21, 0, byte(onuId)}
 	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
 		Type:   layers.DHCPOptRequestIP,
 		Data:   data,
 		Length: uint8(len(data)),
 	})
 	return &dhcpLayer
 }

 func serializeDHCPPacket(intfId uint32, onuId uint32, srcMac net.HardwareAddr, dhcp *layers.DHCPv4) ([]byte, error) {
 	buffer := gopacket.NewSerializeBuffer()
 	options := gopacket.SerializeOptions{
 		ComputeChecksums: true,
 		FixLengths:       true,
 	}

 	ethernetLayer := &layers.Ethernet{
 		SrcMAC:       srcMac,
 		DstMAC:       net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
 		EthernetType: layers.EthernetTypeIPv4,
 	}

 	ipLayer := &layers.IPv4{
 		Version:  4,
 		TOS:      0x10,
 		TTL:      128,
 		SrcIP:    []byte{0, 0, 0, 0},
 		DstIP:    []byte{255, 255, 255, 255},
 		Protocol: layers.IPProtocolUDP,
 	}

 	udpLayer := &layers.UDP{
 		SrcPort: 68,
 		DstPort: 67,
 	}

 	udpLayer.SetNetworkLayerForChecksum(ipLayer)
 	if err := gopacket.SerializeLayers(buffer, options, ethernetLayer, ipLayer, udpLayer, dhcp); err != nil {
 		return nil, err
 	}

 	bytes := buffer.Bytes()
 	return bytes, nil
 }

 func getDhcpLayer(pkt gopacket.Packet) (*layers.DHCPv4, error) {
 	layerDHCP := pkt.Layer(layers.LayerTypeDHCPv4)
 	dhcp, _ := layerDHCP.(*layers.DHCPv4)
 	if dhcp == nil {
 		return nil, errors.New("Failed-to-extract-DHCP-layer")
 	}
 	return dhcp, nil
 }

 func getDhcpMessageType(dhcp *layers.DHCPv4) (layers.DHCPMsgType, error) {
 	for _, option := range dhcp.Options {
 		if option.Type == layers.DHCPOptMessageType {
 			if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeOffer)}) {
 				return layers.DHCPMsgTypeOffer, nil
 			} else if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeAck)}) {
 				return layers.DHCPMsgTypeAck, nil
 			} else if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeRelease)}) {
 				return layers.DHCPMsgTypeRelease, nil
 			} else {
 				msg := fmt.Sprintf("This type %x is not supported", option.Data)
 				return 0, errors.New(msg)
 			}
 		}
 	}
 	return 0, errors.New("Failed to extract MsgType from dhcp")
 }

 func sendDHCPPktIn(msg bbsim.ByteMsg, stream openolt.Openolt_EnableIndicationServer) error {
 	// FIXME unify sendDHCPPktIn and sendEapolPktIn methods
 	gemid, err := omci.GetGemPortId(msg.IntfId, msg.OnuId)
 	if err != nil {
 		dhcpLogger.WithFields(log.Fields{
 			"OnuId":  msg.OnuId,
 			"IntfId": msg.IntfId,
 		}).Errorf("Can't retrieve GemPortId: %s", err)
 		return err
 	}
 	data := &openolt.Indication_PktInd{PktInd: &openolt.PacketIndication{
 		IntfType: "pon", IntfId: msg.IntfId, GemportId: uint32(gemid), Pkt: msg.Bytes,
 	}}

 	if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
 		dhcpLogger.Errorf("Fail to send DHCP PktInd indication. %v", err)
 		return err
 	}
 	return nil
 }

 func sendDHCPDiscovery(ponPortId uint32, onuId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, stream openolt.Openolt_EnableIndicationServer) error {
 	dhcp := createDHCPDisc(ponPortId, onuId)
 	pkt, err := serializeDHCPPacket(ponPortId, onuId, onuHwAddress, dhcp)
 	if err != nil {
 		dhcpLogger.Errorf("Cannot serializeDHCPPacket: %s", err)
 		return err
 	}
 	// NOTE I don't think we need to tag the packet
 	//taggedPkt, err := packetHandlers.PushSingleTag(cTag, pkt)

 	msg := bbsim.ByteMsg{
 		IntfId: ponPortId,
 		OnuId:  onuId,
 		Bytes:  pkt,
 	}

 	if err := sendDHCPPktIn(msg, stream); err != nil {
 		return err
 	}
 	dhcpLogger.WithFields(log.Fields{
 		"OnuId":  onuId,
 		"IntfId": ponPortId,
 		"OnuSn":  serialNumber,
 	}).Infof("DHCPDiscovery Sent")
 	return nil
 }

 func sendDHCPRequest(ponPortId uint32, onuId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, stream openolt.Openolt_EnableIndicationServer) error {
 	dhcp := createDHCPReq(ponPortId, onuId)
 	pkt, err := serializeDHCPPacket(ponPortId, onuId, onuHwAddress, dhcp)

 	if err != nil {
 		dhcpLogger.Errorf("Cannot serializeDHCPPacket: %s", err)
 		return err
 	}
 	// NOTE I don't think we need to tag the packet
 	//taggedPkt, err := packetHandlers.PushSingleTag(cTag, pkt)

 	msg := bbsim.ByteMsg{
 		IntfId: ponPortId,
 		OnuId:  onuId,
 		Bytes:  pkt,
 	}

 	if err := sendDHCPPktIn(msg, stream); err != nil {
 		return err
 	}
 	dhcpLogger.WithFields(log.Fields{
 		"OnuId":  onuId,
 		"IntfId": ponPortId,
 		"OnuSn":  serialNumber,
 	}).Infof("DHCPDiscovery Sent")
 	return nil
 }

 func CreateDHCPClient(onuId uint32, ponPortId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, onuStateMachine *fsm.FSM, stream openolt.Openolt_EnableIndicationServer, pktOutCh chan *bbsim.ByteMsg) {
 	// NOTE pckOutCh is channel to listen on for packets received by VOLTHA
 	// the OLT device will publish messages on that channel

 	dhcpLogger.WithFields(log.Fields{
 		"OnuId":  onuId,
 		"IntfId": ponPortId,
 		"OnuSn":  serialNumber,
 	}).Infof("DHCP State Machine starting")

 	defer dhcpLogger.WithFields(log.Fields{
 		"OnuId":  onuId,
 		"IntfId": ponPortId,
 		"OnuSn":  serialNumber,
 	}).Infof("DHCP State machine completed")

 	// Send DHCP Discovery packet
 	if err := sendDHCPDiscovery(ponPortId, onuId, serialNumber, onuHwAddress, cTag, stream); err != nil {
 		dhcpLogger.WithFields(log.Fields{
 			"OnuId":  onuId,
 			"IntfId": ponPortId,
 			"OnuSn":  serialNumber,
 		}).Errorf("Can't send DHCP Discovery: %s", err)
 		if err := onuStateMachine.Event("dhcp_failed"); err != nil {
 			dhcpLogger.WithFields(log.Fields{
 				"OnuId":  onuId,
 				"IntfId": ponPortId,
 				"OnuSn":  serialNumber,
 			}).Errorf("Error while transitioning ONU State %v", err)
 		}
 		return
 	}

 	if err := onuStateMachine.Event("dhcp_discovery_sent"); err != nil {
 		dhcpLogger.WithFields(log.Fields{
 			"OnuId":  onuId,
 			"IntfId": ponPortId,
 			"OnuSn":  serialNumber,
 		}).Errorf("Error while transitioning ONU State %v", err)
 	}

 	dhcpLogger.WithFields(log.Fields{
 		"OnuId":  onuId,
 		"IntfId": ponPortId,
 		"OnuSn":  serialNumber,
 	}).Infof("Listening on dhcpPktOutCh")

 	for msg := range pktOutCh {
 		dhcpLogger.Tracef("Received DHCP message %v", msg)

 		pkt := gopacket.NewPacket(msg.Bytes, layers.LayerTypeEthernet, gopacket.Default)
 		dhcpLayer, err := getDhcpLayer(pkt)
 		if err != nil {
 			dhcpLogger.WithFields(log.Fields{
 				"OnuId":  onuId,
 				"IntfId": ponPortId,
 				"OnuSn":  serialNumber,
 			}).Errorf("Can't get DHCP Layer from Packet: %v", err)
 			continue
 		}
 		dhcpMessageType, err := getDhcpMessageType(dhcpLayer)
 		if err != nil {
 			dhcpLogger.WithFields(log.Fields{
 				"OnuId":  onuId,
 				"IntfId": ponPortId,
 				"OnuSn":  serialNumber,
 			}).Errorf("Can't get DHCP Message Type from DHCP Layer: %v", err)
 			continue
 		}

 		if dhcpLayer.Operation == layers.DHCPOpReply {
 			if dhcpMessageType == layers.DHCPMsgTypeOffer {
 				if err := sendDHCPRequest(ponPortId, onuId, serialNumber, onuHwAddress, cTag, stream); err != nil {
 					dhcpLogger.WithFields(log.Fields{
 						"OnuId":  onuId,
 						"IntfId": ponPortId,
 						"OnuSn":  serialNumber,
 					}).Errorf("Can't send DHCP Request: %s", err)
 					if err := onuStateMachine.Event("dhcp_failed"); err != nil {
 						dhcpLogger.WithFields(log.Fields{
 							"OnuId":  onuId,
 							"IntfId": ponPortId,
 							"OnuSn":  serialNumber,
 						}).Errorf("Error while transitioning ONU State %v", err)
 					}
 					return
 				}
 				if err := onuStateMachine.Event("dhcp_request_sent"); err != nil {
 					dhcpLogger.WithFields(log.Fields{
 						"OnuId":  onuId,
 						"IntfId": ponPortId,
 						"OnuSn":  serialNumber,
 					}).Errorf("Error while transitioning ONU State %v", err)
 				}

 			} else if dhcpMessageType == layers.DHCPMsgTypeAck {
 				// NOTE once the ack is received we don't need to do anything but change the state
 				if err := onuStateMachine.Event("dhcp_ack_received"); err != nil {
 					dhcpLogger.WithFields(log.Fields{
 						"OnuId":  onuId,
 						"IntfId": ponPortId,
 						"OnuSn":  serialNumber,
 					}).Errorf("Error while transitioning ONU State %v", err)
 				}
 				return
 			}
 			// NOTE do we need to care about DHCPMsgTypeRelease??
 		} else {
 			dhcpLogger.WithFields(log.Fields{
 				"OnuId":  onuId,
 				"IntfId": ponPortId,
 				"OnuSn":  serialNumber,
 			}).Warnf("Unsupported DHCP Operation: %s", dhcpLayer.Operation.String())
 			continue
 		}
 	}
 }
	/*
	* Copyright 2018-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 dhcp

	import (
	"errors"
	"fmt"
	"github.com/google/gopacket"
	"github.com/google/gopacket/layers"
	"github.com/looplab/fsm"
	bbsim "github.com/opencord/bbsim/internal/bbsim/types"
	omci "github.com/opencord/omci-sim"
	"github.com/opencord/voltha-protos/go/openolt"
	log "github.com/sirupsen/logrus"
	"net"
	"reflect"
	)

	var dhcpLogger = log.WithFields(log.Fields{
	"module": "DHCP",
	})

	var defaultParamsRequestList = []layers.DHCPOpt{
	layers.DHCPOptSubnetMask,
	layers.DHCPOptBroadcastAddr,
	layers.DHCPOptTimeOffset,
	layers.DHCPOptRouter,
	layers.DHCPOptDomainName,
	layers.DHCPOptDNS,
	layers.DHCPOptDomainSearch,
	layers.DHCPOptHostname,
	layers.DHCPOptNetBIOSTCPNS,
	layers.DHCPOptNetBIOSTCPScope,
	layers.DHCPOptInterfaceMTU,
	layers.DHCPOptClasslessStaticRoute,
	layers.DHCPOptNTPServers,
	}

	func createDefaultDHCPReq(intfId uint32, onuId uint32) layers.DHCPv4 {
	return layers.DHCPv4{
	Operation: layers.DHCPOpRequest,
	HardwareType: layers.LinkTypeEthernet,
	HardwareLen: 6,
	HardwareOpts: 0,
	Xid: onuId,
	ClientHWAddr: net.HardwareAddr{0x2e, 0x60, 0x70, 0x13, byte(intfId), byte(onuId)},
	}
	}

	func createDefaultOpts() []layers.DHCPOption {
	hostname := []byte("bbsim.onf.org")
	opts := []layers.DHCPOption{}
	opts = append(opts, layers.DHCPOption{
	Type: layers.DHCPOptHostname,
	Data: hostname,
	Length: uint8(len(hostname)),
	})

	bytes := []byte{}
	for _, option := range defaultParamsRequestList {
	bytes = append(bytes, byte(option))
	}

	opts = append(opts, layers.DHCPOption{
	Type: layers.DHCPOptParamsRequest,
	Data: bytes,
	Length: uint8(len(bytes)),
	})
	return opts
	}

	func createDHCPDisc(intfId uint32, onuId uint32) *layers.DHCPv4 {
	dhcpLayer := createDefaultDHCPReq(intfId, onuId)
	defaultOpts := createDefaultOpts()
	dhcpLayer.Options = append([]layers.DHCPOption{layers.DHCPOption{
	Type: layers.DHCPOptMessageType,
	Data: []byte{byte(layers.DHCPMsgTypeDiscover)},
	Length: 1,
	}}, defaultOpts...)

	return &dhcpLayer
	}

	func createDHCPReq(intfId uint32, onuId uint32) *layers.DHCPv4 {
	dhcpLayer := createDefaultDHCPReq(intfId, onuId)
	defaultOpts := createDefaultOpts()

	dhcpLayer.Options = append(defaultOpts, layers.DHCPOption{
	Type: layers.DHCPOptMessageType,
	Data: []byte{byte(layers.DHCPMsgTypeRequest)},
	Length: 1,
	})

	data := []byte{182, 21, 0, 128}
	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
	Type: layers.DHCPOptServerID,
	Data: data,
	Length: uint8(len(data)),
	})

	data = []byte{0xcd, 0x28, 0xcb, 0xcc, 0x00, 0x01, 0x00, 0x01,
	0x23, 0xed, 0x11, 0xec, 0x4e, 0xfc, 0xcd, 0x28, 0xcb, 0xcc}
	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
	Type: layers.DHCPOptClientID,
	Data: data,
	Length: uint8(len(data)),
	})

	data = []byte{182, 21, 0, byte(onuId)}
	dhcpLayer.Options = append(dhcpLayer.Options, layers.DHCPOption{
	Type: layers.DHCPOptRequestIP,
	Data: data,
	Length: uint8(len(data)),
	})
	return &dhcpLayer
	}

	func serializeDHCPPacket(intfId uint32, onuId uint32, srcMac net.HardwareAddr, dhcp *layers.DHCPv4) ([]byte, error) {
	buffer := gopacket.NewSerializeBuffer()
	options := gopacket.SerializeOptions{
	ComputeChecksums: true,
	FixLengths: true,
	}

	ethernetLayer := &layers.Ethernet{
	SrcMAC: srcMac,
	DstMAC: net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
	EthernetType: layers.EthernetTypeIPv4,
	}

	ipLayer := &layers.IPv4{
	Version: 4,
	TOS: 0x10,
	TTL: 128,
	SrcIP: []byte{0, 0, 0, 0},
	DstIP: []byte{255, 255, 255, 255},
	Protocol: layers.IPProtocolUDP,
	}

	udpLayer := &layers.UDP{
	SrcPort: 68,
	DstPort: 67,
	}

	udpLayer.SetNetworkLayerForChecksum(ipLayer)
	if err := gopacket.SerializeLayers(buffer, options, ethernetLayer, ipLayer, udpLayer, dhcp); err != nil {
	return nil, err
	}

	bytes := buffer.Bytes()
	return bytes, nil
	}

	func getDhcpLayer(pkt gopacket.Packet) (*layers.DHCPv4, error) {
	layerDHCP := pkt.Layer(layers.LayerTypeDHCPv4)
	dhcp, _ := layerDHCP.(*layers.DHCPv4)
	if dhcp == nil {
	return nil, errors.New("Failed-to-extract-DHCP-layer")
	}
	return dhcp, nil
	}

	func getDhcpMessageType(dhcp *layers.DHCPv4) (layers.DHCPMsgType, error) {
	for _, option := range dhcp.Options {
	if option.Type == layers.DHCPOptMessageType {
	if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeOffer)}) {
	return layers.DHCPMsgTypeOffer, nil
	} else if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeAck)}) {
	return layers.DHCPMsgTypeAck, nil
	} else if reflect.DeepEqual(option.Data, []byte{byte(layers.DHCPMsgTypeRelease)}) {
	return layers.DHCPMsgTypeRelease, nil
	} else {
	msg := fmt.Sprintf("This type %x is not supported", option.Data)
	return 0, errors.New(msg)
	}
	}
	}
	return 0, errors.New("Failed to extract MsgType from dhcp")
	}

	func sendDHCPPktIn(msg bbsim.ByteMsg, stream openolt.Openolt_EnableIndicationServer) error {
	// FIXME unify sendDHCPPktIn and sendEapolPktIn methods
	gemid, err := omci.GetGemPortId(msg.IntfId, msg.OnuId)
	if err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": msg.OnuId,
	"IntfId": msg.IntfId,
	}).Errorf("Can't retrieve GemPortId: %s", err)
	return err
	}
	data := &openolt.Indication_PktInd{PktInd: &openolt.PacketIndication{
	IntfType: "pon", IntfId: msg.IntfId, GemportId: uint32(gemid), Pkt: msg.Bytes,
	}}

	if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
	dhcpLogger.Errorf("Fail to send DHCP PktInd indication. %v", err)
	return err
	}
	return nil
	}

	func sendDHCPDiscovery(ponPortId uint32, onuId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, stream openolt.Openolt_EnableIndicationServer) error {
	dhcp := createDHCPDisc(ponPortId, onuId)
	pkt, err := serializeDHCPPacket(ponPortId, onuId, onuHwAddress, dhcp)
	if err != nil {
	dhcpLogger.Errorf("Cannot serializeDHCPPacket: %s", err)
	return err
	}
	// NOTE I don't think we need to tag the packet
	//taggedPkt, err := packetHandlers.PushSingleTag(cTag, pkt)

	msg := bbsim.ByteMsg{
	IntfId: ponPortId,
	OnuId: onuId,
	Bytes: pkt,
	}

	if err := sendDHCPPktIn(msg, stream); err != nil {
	return err
	}
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Infof("DHCPDiscovery Sent")
	return nil
	}

	func sendDHCPRequest(ponPortId uint32, onuId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, stream openolt.Openolt_EnableIndicationServer) error {
	dhcp := createDHCPReq(ponPortId, onuId)
	pkt, err := serializeDHCPPacket(ponPortId, onuId, onuHwAddress, dhcp)

	if err != nil {
	dhcpLogger.Errorf("Cannot serializeDHCPPacket: %s", err)
	return err
	}
	// NOTE I don't think we need to tag the packet
	//taggedPkt, err := packetHandlers.PushSingleTag(cTag, pkt)

	msg := bbsim.ByteMsg{
	IntfId: ponPortId,
	OnuId: onuId,
	Bytes: pkt,
	}

	if err := sendDHCPPktIn(msg, stream); err != nil {
	return err
	}
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Infof("DHCPDiscovery Sent")
	return nil
	}

	func CreateDHCPClient(onuId uint32, ponPortId uint32, serialNumber string, onuHwAddress net.HardwareAddr, cTag int, onuStateMachine fsm.FSM, stream openolt.Openolt_EnableIndicationServer, pktOutCh chan bbsim.ByteMsg) {
	// NOTE pckOutCh is channel to listen on for packets received by VOLTHA
	// the OLT device will publish messages on that channel

	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Infof("DHCP State Machine starting")

	defer dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Infof("DHCP State machine completed")

	// Send DHCP Discovery packet
	if err := sendDHCPDiscovery(ponPortId, onuId, serialNumber, onuHwAddress, cTag, stream); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Can't send DHCP Discovery: %s", err)
	if err := onuStateMachine.Event("dhcp_failed"); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Error while transitioning ONU State %v", err)
	}
	return
	}

	if err := onuStateMachine.Event("dhcp_discovery_sent"); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Error while transitioning ONU State %v", err)
	}

	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Infof("Listening on dhcpPktOutCh")

	for msg := range pktOutCh {
	dhcpLogger.Tracef("Received DHCP message %v", msg)

	pkt := gopacket.NewPacket(msg.Bytes, layers.LayerTypeEthernet, gopacket.Default)
	dhcpLayer, err := getDhcpLayer(pkt)
	if err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Can't get DHCP Layer from Packet: %v", err)
	continue
	}
	dhcpMessageType, err := getDhcpMessageType(dhcpLayer)
	if err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Can't get DHCP Message Type from DHCP Layer: %v", err)
	continue
	}

	if dhcpLayer.Operation == layers.DHCPOpReply {
	if dhcpMessageType == layers.DHCPMsgTypeOffer {
	if err := sendDHCPRequest(ponPortId, onuId, serialNumber, onuHwAddress, cTag, stream); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Can't send DHCP Request: %s", err)
	if err := onuStateMachine.Event("dhcp_failed"); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Error while transitioning ONU State %v", err)
	}
	return
	}
	if err := onuStateMachine.Event("dhcp_request_sent"); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Error while transitioning ONU State %v", err)
	}

	} else if dhcpMessageType == layers.DHCPMsgTypeAck {
	// NOTE once the ack is received we don't need to do anything but change the state
	if err := onuStateMachine.Event("dhcp_ack_received"); err != nil {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Errorf("Error while transitioning ONU State %v", err)
	}
	return
	}
	// NOTE do we need to care about DHCPMsgTypeRelease??
	} else {
	dhcpLogger.WithFields(log.Fields{
	"OnuId": onuId,
	"IntfId": ponPortId,
	"OnuSn": serialNumber,
	}).Warnf("Unsupported DHCP Operation: %s", dhcpLayer.Operation.String())
	continue
	}
	}
	}