ing

api/module/discovery/model/service.go

@@ -4,6 +4,6 @@ type Service struct {
 	Port *Port `json:"port,omitempty"`
 
 	ID          int    `json:"id,omitempty"`
-	TLSType     string `json:"tlsType,omitempty"`
+	CryptoType  string `json:"cryptoType,omitempty"`
 	ServiceName string `json:"serviceName,omitempty"`
 }

commons/pcap/packet.go

@@ -0,0 +1,109 @@
+package pcap
+
+import (
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+)
+
+type PacketType int
+
+const (
+	PacketTypeUnknown PacketType = iota
+	PacketTypeARP
+	PacketTypeTCP
+	PacketTypeUDP
+)
+
+func getPacketType(packet gopacket.Packet) PacketType {
+	if packet == nil {
+		return PacketTypeUnknown
+	}
+	layer := packet.Layer(layers.LayerTypeARP)
+	if layer != nil {
+		return PacketTypeARP
+	}
+
+	layer = packet.Layer(layers.LayerTypeTCP)
+	if layer != nil {
+		if _, ok := layer.(*layers.TCP); ok {
+			return PacketTypeTCP
+		}
+	}
+
+	layer = packet.Layer(layers.LayerTypeUDP)
+	if layer != nil {
+		if _, ok := layer.(*layers.UDP); ok {
+			return PacketTypeUDP
+		}
+	}
+	return PacketTypeUnknown
+}
+
+func handlePacket(ps *pCapScan, packet gopacket.Packet) {
+	switch getPacketType(packet) {
+	case PacketTypeARP:
+		handlePacketARP(ps, packet)
+	case PacketTypeTCP:
+		handlePacketTCP(ps, packet)
+	case PacketTypeUDP:
+		handlePacketUDP(ps, packet)
+	default:
+	}
+}
+
+func handlePacketARP(ps *pCapScan, packet gopacket.Packet) {
+	ps.arpListenerChanMtx.RLock()
+	defer ps.arpListenerChanMtx.RUnlock()
+
+	if ps.arpListenerChans != nil {
+		arpLayer := packet.Layer(layers.LayerTypeARP)
+		arp := arpLayer.(*layers.ARP)
+
+		for _, ch := range ps.arpListenerChans {
+			ch <- arp
+		}
+	}
+}
+
+func handlePacketTCP(ps *pCapScan, packet gopacket.Packet) {
+	ipLayer := packet.Layer(layers.LayerTypeIPv4)
+	if nil == ipLayer {
+		return
+	}
+
+	ip := ipLayer.(*layers.IPv4).SrcIP.String()
+
+	ps.tcpListenerChanMtx.RLock()
+	defer ps.tcpListenerChanMtx.RUnlock()
+
+	chs, ok := ps.tcpListenerChans[ip]
+	if ok {
+
+		layer := packet.Layer(layers.LayerTypeTCP)
+		tcp, _ := layer.(*layers.TCP)
+
+		for _, ch := range chs {
+			ch <- tcp
+		}
+	}
+}
+
+func handlePacketUDP(ps *pCapScan, packet gopacket.Packet) {
+	ipLayer := packet.Layer(layers.LayerTypeIPv4)
+	if nil == ipLayer {
+		return
+	}
+
+	ip := ipLayer.(*layers.IPv4).SrcIP.String()
+
+	ps.udpListenerChanMtx.RLock()
+	defer ps.udpListenerChanMtx.RUnlock()
+
+	chs, ok := ps.udpListenerChans[ip]
+	if ok {
+
+		for _, ch := range chs {
+			ch <- packet
+		}
+	}
+}

commons/pcap/pcap.go

@@ -0,0 +1,54 @@
+package pcap
+
+import (
+	"sync"
+
+	"git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
+)
+
+var mtx sync.Mutex
+var instances map[string]PCapScanner
+
+func init() {
+	instances = make(map[string]PCapScanner, 0)
+}
+
+func RetainScanner(zone *model.Zone) (PCapScanner, error) {
+	mtx.Lock()
+	defer mtx.Unlock()
+
+	var ps PCapScanner
+	var ok bool
+	if ps, ok = instances[zone.Network]; !ok {
+		ps = newPCapScanner(zone)
+		if err := ps.start(); nil != err {
+			return nil, err
+		}
+		instances[zone.Network] = ps
+	}
+	ps.retain()
+
+	return ps, nil
+}
+
+func ReleaseScanner(zone *model.Zone) {
+	mtx.Lock()
+	defer mtx.Unlock()
+
+	if ps, ok := instances[zone.Network]; ok {
+		if ps.release() {
+			ps.stop()
+			delete(instances, zone.Network)
+		}
+	}
+}
+
+func ReleaseScannerAll() {
+	mtx.Lock()
+	defer mtx.Unlock()
+
+	for k, ps := range instances {
+		ps.stop()
+		delete(instances, k)
+	}
+}

commons/pcap/pcap_scan.go

@@ -0,0 +1,247 @@
+package pcap
+
+import (
+	"fmt"
+	"sort"
+	"sync"
+
+	"git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/google/gopacket/pcap"
+)
+
+func newPCapScanner(zone *model.Zone) PCapScanner {
+	ps := &pCapScan{
+		zone: zone,
+	}
+
+	return ps
+}
+
+type PCapScanner interface {
+	OpenARP() chan *layers.ARP
+	CloseARP(ch chan *layers.ARP)
+
+	OpenTCP(ip string) chan *layers.TCP
+	CloseTCP(ip string, ch chan *layers.TCP)
+
+	OpenUDP(ip string) chan gopacket.Packet
+	CloseUDP(ip string, ch chan gopacket.Packet)
+
+	WritePacketData(data []byte) (err error)
+
+	start() error
+	stop()
+
+	retain()
+	release() bool
+}
+
+type pCapScan struct {
+	zone       *model.Zone
+	pCapHandle *pcap.Handle
+
+	arpListenerChanMtx sync.RWMutex
+	arpListenerChans   []chan *layers.ARP
+
+	tcpListenerChanMtx sync.RWMutex
+	tcpListenerChans   map[string][]chan *layers.TCP
+
+	udpListenerChanMtx sync.RWMutex
+	udpListenerChans   map[string][]chan gopacket.Packet
+
+	refCount int
+	stopChan chan struct{}
+	stopWg   sync.WaitGroup
+}
+
+func (ps *pCapScan) start() error {
+	if ps.stopChan != nil {
+		return fmt.Errorf("PCapScanner: already running. Stop it before starting it again")
+	}
+
+	// new pcap handle
+	var h *pcap.Handle
+	var err error
+	if h, err = pcap.OpenLive(ps.zone.Iface, 65536, true, pcap.BlockForever); nil != err {
+		return err
+	}
+	// set filter
+	// todo add tcp, udp filter
+	if err = h.SetBPFFilter("arp and src net " + ps.zone.Network + " or (((tcp[tcpflags] & (tcp-syn|tcp-ack) != 0) or (tcp[tcpflags] & (tcp-rst) != 0)) and port 60000) or udp "); nil != err {
+		h.Close()
+		return err
+	}
+
+	ps.arpListenerChans = make([]chan *layers.ARP, 0)
+	ps.tcpListenerChans = make(map[string][]chan *layers.TCP, 0)
+	ps.udpListenerChans = make(map[string][]chan gopacket.Packet, 0)
+
+	ps.stopChan = make(chan struct{})
+
+	ps.stopWg.Add(1)
+	go handleReceive(ps)
+
+	return nil
+}
+
+func (ps *pCapScan) stop() {
+	if ps.stopChan == nil {
+		panic("PCapScanner: must be started before stopping it")
+	}
+	close(ps.stopChan)
+	ps.stopWg.Wait()
+	ps.stopChan = nil
+}
+
+func (ps *pCapScan) OpenARP() chan *layers.ARP {
+	ps.arpListenerChanMtx.Lock()
+	defer ps.arpListenerChanMtx.Unlock()
+
+	c := make(chan *layers.ARP, 0)
+	ps.arpListenerChans = append(ps.arpListenerChans, c)
+	return c
+}
+func (ps *pCapScan) CloseARP(ch chan *layers.ARP) {
+	ps.arpListenerChanMtx.Lock()
+	defer ps.arpListenerChanMtx.Unlock()
+
+	i := sort.Search(len(ps.arpListenerChans), func(i int) bool {
+		return ch == ps.arpListenerChans[i]
+	})
+
+	if -1 != i {
+		close(ch)
+		ps.arpListenerChans = append(ps.arpListenerChans[:i], ps.arpListenerChans[i+1:]...)
+	}
+}
+
+func (ps *pCapScan) OpenTCP(ip string) chan *layers.TCP {
+	ps.tcpListenerChanMtx.Lock()
+	defer ps.tcpListenerChanMtx.Unlock()
+
+	if _, ok := ps.tcpListenerChans[ip]; !ok {
+		ps.tcpListenerChans[ip] = make([]chan *layers.TCP, 0)
+	}
+
+	ch := make(chan *layers.TCP, 0)
+	ps.tcpListenerChans[ip] = append(ps.tcpListenerChans[ip], ch)
+
+	return ch
+}
+func (ps *pCapScan) CloseTCP(ip string, ch chan *layers.TCP) {
+	ps.tcpListenerChanMtx.Lock()
+	defer ps.tcpListenerChanMtx.Unlock()
+
+	if _, ok := ps.tcpListenerChans[ip]; !ok {
+		return
+	}
+
+	chs := ps.tcpListenerChans[ip]
+	i := sort.Search(len(chs), func(i int) bool {
+		return ch == chs[i]
+	})
+
+	if -1 != i {
+		close(ch)
+		ps.tcpListenerChans[ip] = append(ps.tcpListenerChans[ip][:i], ps.tcpListenerChans[ip][i+1:]...)
+	}
+
+}
+
+func (ps *pCapScan) OpenUDP(ip string) chan gopacket.Packet {
+	ps.udpListenerChanMtx.Lock()
+	defer ps.udpListenerChanMtx.Unlock()
+
+	if _, ok := ps.udpListenerChans[ip]; !ok {
+		ps.udpListenerChans[ip] = make([]chan gopacket.Packet, 0)
+	}
+
+	ch := make(chan gopacket.Packet, 0)
+	ps.udpListenerChans[ip] = append(ps.udpListenerChans[ip], ch)
+
+	return ch
+
+}
+func (ps *pCapScan) CloseUDP(ip string, ch chan gopacket.Packet) {
+	ps.udpListenerChanMtx.Lock()
+	defer ps.udpListenerChanMtx.Unlock()
+
+	if _, ok := ps.udpListenerChans[ip]; !ok {
+		return
+	}
+
+	chs := ps.udpListenerChans[ip]
+	i := sort.Search(len(chs), func(i int) bool {
+		return ch == chs[i]
+	})
+
+	if -1 != i {
+		close(ch)
+		ps.udpListenerChans[ip] = append(ps.udpListenerChans[ip][:i], ps.udpListenerChans[ip][i+1:]...)
+	}
+}
+
+func (ps *pCapScan) WritePacketData(data []byte) (err error) {
+	return ps.pCapHandle.WritePacketData(data)
+}
+
+func (ps *pCapScan) retain() {
+	ps.refCount++
+}
+func (ps *pCapScan) release() bool {
+	ps.refCount--
+	if 0 > ps.refCount {
+		ps.refCount = 0
+	}
+	return 0 == ps.refCount
+}
+
+func (ps *pCapScan) destroy() {
+	ps.tcpListenerChanMtx.Lock()
+	for k, v := range ps.tcpListenerChans {
+		for _, ch := range v {
+			close(ch)
+		}
+		v = v[:0]
+		delete(ps.tcpListenerChans, k)
+	}
+	ps.tcpListenerChanMtx.Unlock()
+
+	ps.udpListenerChanMtx.Lock()
+	for k, v := range ps.udpListenerChans {
+		for _, ch := range v {
+			close(ch)
+		}
+		v = v[:0]
+		delete(ps.udpListenerChans, k)
+	}
+	ps.udpListenerChanMtx.Unlock()
+
+	ps.arpListenerChanMtx.Lock()
+	for _, v := range ps.arpListenerChans {
+		close(v)
+	}
+	ps.arpListenerChans = ps.arpListenerChans[:0]
+	ps.arpListenerChanMtx.Unlock()
+
+	ps.pCapHandle.Close()
+}
+
+func handleReceive(ps *pCapScan) {
+	defer ps.stopWg.Done()
+
+	pSrc := gopacket.NewPacketSource(ps.pCapHandle, layers.LayerTypeEthernet)
+	inPacket := pSrc.Packets()
+
+	for {
+		select {
+		case packet := <-inPacket:
+			handlePacket(ps, packet)
+		case <-ps.stopChan:
+			ps.destroy()
+		}
+	}
+}

discovery/discovery.go

@@ -71,140 +71,60 @@ func (d *discovery) stop() {
 }
 
 func (d *discovery) discoverZone(dz *model.DiscoveryZone) {
-	logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverZone is start"))
-
-	d.stopWg.Add(1)
-	resultChan := make(chan *model.Zone)
-	errChan := make(chan error)
-	doneChan := make(chan struct{})
-
-	defer func() {
-		close(resultChan)
-		close(errChan)
-		close(doneChan)
-		d.stopWg.Done()
-	}()
-
-	go scanZone(dz, resultChan, errChan, doneChan)
-
-	for {
-		select {
-		case z := <-resultChan:
+	taskScan(d,
+		func(resultChan chan interface{}, errChan chan error, doneChan chan struct{}) {
+			scanZone(dz, resultChan, errChan, doneChan)
+		},
+		func(result interface{}) {
+			z := result.(*model.Zone)
 			logging.Logger().Info(fmt.Sprintf("zone: %v", z))
 			if nil != dz.DiscoveryHost {
 				d.discoverHost(z, dz.DiscoveryHost)
 			}
-		case err := <-errChan:
-			logging.Logger().Info(fmt.Sprintf("zone err: %v", err))
-		case <-d.stopChan:
-			return
-		case <-doneChan:
-			logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverZone is complete"))
-			return
-		}
-	}
+		},
+	)
 }
 
 func (d *discovery) discoverHost(zone *model.Zone, dh *model.DiscoveryHost) {
-	logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverHost is start"))
-
-	d.stopWg.Add(1)
-	resultChan := make(chan *model.Host)
-	errChan := make(chan error)
-	doneChan := make(chan struct{})
-
-	defer func() {
-		close(resultChan)
-		close(errChan)
-		close(doneChan)
-		d.stopWg.Done()
-	}()
-
-	go scanHost(zone, dh, resultChan, errChan, doneChan)
-
-	for {
-		select {
-		case h := <-resultChan:
+	taskScan(d,
+		func(resultChan chan interface{}, errChan chan error, doneChan chan struct{}) {
+			scanHost(zone, dh, resultChan, errChan, doneChan)
+		},
+		func(result interface{}) {
+			h := result.(*model.Host)
 			logging.Logger().Info(fmt.Sprintf("host: %v", h))
 			if nil != dh.DiscoveryPort {
 				d.discoverPort(h, dh.DiscoveryPort)
 			}
-		case err := <-errChan:
-			logging.Logger().Info(fmt.Sprintf("host err: %v", err))
-		case <-d.stopChan:
-			return
-		case <-doneChan:
-			logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverHost is complete"))
-			return
-		}
-	}
+		},
+	)
 }
 
 func (d *discovery) discoverPort(host *model.Host, dp *model.DiscoveryPort) {
-	logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverPort is start"))
-
-	d.stopWg.Add(1)
-	resultChan := make(chan *model.Port)
-	errChan := make(chan error)
-	doneChan := make(chan struct{})
-
-	defer func() {
-		close(resultChan)
-		close(errChan)
-		close(doneChan)
-		d.stopWg.Done()
-	}()
-
-	go scanPort(host, dp, resultChan, errChan, doneChan)
-
-	for {
-		select {
-		case p := <-resultChan:
+	taskScan(d,
+		func(resultChan chan interface{}, errChan chan error, doneChan chan struct{}) {
+			scanPort(host, dp, resultChan, errChan, doneChan)
+		},
+		func(result interface{}) {
+			p := result.(*model.Port)
 			logging.Logger().Info(fmt.Sprintf("port: %v", p))
 			if nil != dp.DiscoveryService {
 				d.discoverService(p, dp.DiscoveryService)
 			}
-		case err := <-errChan:
-			logging.Logger().Info(fmt.Sprintf("port err: %v", err))
-		case <-d.stopChan:
-			return
-		case <-doneChan:
-			logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverPort is complete"))
-			return
-		}
-	}
+		},
+	)
 }
 
 func (d *discovery) discoverService(port *model.Port, ds *model.DiscoveryService) {
-	logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverService is start"))
-
-	d.stopWg.Add(1)
-	resultChan := make(chan *model.Service)
-	errChan := make(chan error)
-	doneChan := make(chan struct{})
-
-	defer func() {
-		close(resultChan)
-		close(errChan)
-		close(doneChan)
-		d.stopWg.Done()
-	}()
-
-	go scanService(port, ds, resultChan, errChan, doneChan)
-
-	for {
-		select {
-		case s := <-resultChan:
+	taskScan(d,
+		func(resultChan chan interface{}, errChan chan error, doneChan chan struct{}) {
+			scanService(port, ds, resultChan, errChan, doneChan)
+		},
+		func(result interface{}) {
+			s := result.(*model.Service)
 			logging.Logger().Info(fmt.Sprintf("service: %v", s))
-		case err := <-errChan:
-			logging.Logger().Info(fmt.Sprintf("service err: %v", err))
-		case <-d.stopChan:
-			return
-		case <-doneChan:
-			logging.Logger().Debug(fmt.Sprintf("Discovery: DiscoverService is complete"))
-			return
-		}
-	}
+		},
+	)
 }
 
 func (d *discovery) sendResult() {
@@ -214,3 +134,33 @@ func (d *discovery) sendResult() {
 func (d *discovery) sendError() {
 
 }
+
+func taskScan(d *discovery, task func(resultChan chan interface{}, errChan chan error, doneChan chan struct{}), onResult func(result interface{})) {
+	d.stopWg.Add(1)
+	resultChan := make(chan interface{})
+	errChan := make(chan error)
+	doneChan := make(chan struct{})
+
+	defer func() {
+		close(resultChan)
+		close(errChan)
+		close(doneChan)
+		d.stopWg.Done()
+	}()
+
+	go task(resultChan, errChan, doneChan)
+
+	for {
+		select {
+		case r := <-resultChan:
+			onResult(r)
+		case err := <-errChan:
+			logging.Logger().Info(fmt.Sprintf("task err: %v", err))
+		case <-doneChan:
+			logging.Logger().Debug(fmt.Sprintf("Discovery: task is complete"))
+			return
+		case <-d.stopChan:
+			return
+		}
+	}
+}

discovery/host.go

@@ -1,8 +1,166 @@
 package discovery
 
-import "git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
+import (
+	"bytes"
+	"fmt"
+	"net"
+	"time"
 
-func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan *model.Host, errChan chan error, doneChan chan<- struct{}) {
+	"git.loafle.net/commons_go/logging"
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
 
-	doneChan <- struct{}{}
+	"git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
+	"git.loafle.net/overflow/overflow_discovery/commons/pcap"
+)
+
+func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan interface{}, errChan chan error, doneChan chan<- struct{}) {
+	ps, err := pcap.RetainScanner(zone)
+	if nil != err {
+		errChan <- fmt.Errorf("Discovery: Cannot retain pcap instance %v", err)
+		// doneChan <- struct{}{}
+		return
+	}
+
+	arpChan := ps.OpenARP()
+	defer func() {
+		if nil != ps {
+			ps.CloseARP(arpChan)
+			pcap.ReleaseScanner(zone)
+		}
+		doneChan <- struct{}{}
+	}()
+
+	go func() {
+		for {
+			select {
+			case packet, ok := <-arpChan:
+				if !ok {
+					logging.Logger().Debug(fmt.Sprintf("Discovery: arp channel is closed"))
+					return
+				}
+				logging.Logger().Debug(fmt.Sprintf("Discovery: arp packet %v", packet))
+			}
+		}
+	}()
+
+	time.Sleep(10 * time.Second)
+}
+
+func sendARP(ps pcap.PCapScanner, zone *model.Zone, dh *model.DiscoveryHost) error {
+	hwAddr, err := net.ParseMAC(zone.Mac)
+	if nil != err {
+		return err
+	}
+	ip := net.ParseIP(zone.IP)
+	if nil != ip {
+		return fmt.Errorf("Discovery: IP(%s) of zone is not valid", zone.IP)
+	}
+
+	ranges, err := getTargetHostRange(zone, dh)
+	if nil != err {
+		return err
+	}
+
+	ethPacket := makePacketEthernet(hwAddr)
+	arpPacket := makePacketARP(hwAddr, ip)
+	opts := gopacket.SerializeOptions{FixLengths: true, ComputeChecksums: true}
+	buf := gopacket.NewSerializeBuffer()
+
+	for _, targetHost := range ranges {
+		arpPacket.DstProtAddress = []byte(targetHost)
+		gopacket.SerializeLayers(buf, opts, ethPacket, arpPacket)
+		// if err := ps.WritePacketData(buf.Bytes()); err != nil {
+		// 	return err
+		// }
+		time.Sleep(time.Microsecond * 500)
+	}
+	return nil
+}
+
+func getTargetHostRange(zone *model.Zone, dh *model.DiscoveryHost) ([]net.IP, error) {
+	nIP, nIPNet, err := net.ParseCIDR(zone.Network)
+	if nil != err {
+		return nil, fmt.Errorf("Discovery: Network(%s) of zone is not valid", zone.Network)
+	}
+
+	firstIP := net.ParseIP(dh.FirstScanRange)
+	lastIP := net.ParseIP(dh.LastScanRange)
+	if nil == firstIP || nil == lastIP {
+		return nil, fmt.Errorf("Discovery: IP Range(First:%s, Last:%s) is not valid", dh.FirstScanRange, dh.LastScanRange)
+	}
+
+	firstIP16 := firstIP.To16()
+	lastIP16 := lastIP.To16()
+	if nil == firstIP16 || nil == lastIP16 {
+		return nil, fmt.Errorf("Discovery: IP Range(First:%s, Last:%s) is not valid", dh.FirstScanRange, dh.LastScanRange)
+	}
+
+	excludeIP16s := make([]net.IP, 0)
+	for _, eHost := range dh.ExcludeHosts {
+		eIP := net.ParseIP(eHost)
+		if nil == eIP {
+			return nil, fmt.Errorf("Discovery: IP(%v) of exclude host is not valid", eHost)
+		}
+		eIP16 := eIP.To16()
+		if nil == eIP16 {
+			return nil, fmt.Errorf("Discovery: IP(%v) of exclude host is not valid", eHost)
+		}
+		excludeIP16s = append(excludeIP16s, eIP16)
+	}
+
+	ranges := make([]net.IP, 0)
+
+	ip := nIP
+Loop:
+	for ip := ip.Mask(nIPNet.Mask); nIPNet.Contains(ip); inc(ip) {
+		ip16 := ip.To16()
+		if nil == ip16 {
+			return nil, fmt.Errorf("Discovery: IP(%v) converting is failed", ip)
+		}
+
+		if 0 > bytes.Compare(ip16, firstIP16) || 0 < bytes.Compare(ip16, lastIP16) {
+			continue
+		}
+
+		for _, eIP16 := range excludeIP16s {
+			if 0 == bytes.Compare(eIP16, ip16) {
+				continue Loop
+			}
+		}
+
+		ranges = append(ranges, ip)
+	}
+
+	return ranges, nil
+}
+
+func inc(ip net.IP) {
+	for j := len(ip) - 1; j >= 0; j-- {
+		ip[j]++
+		if ip[j] > 0 {
+			break
+		}
+	}
+}
+
+func makePacketEthernet(hw net.HardwareAddr) *layers.Ethernet {
+	return &layers.Ethernet{
+		SrcMAC:       hw,
+		DstMAC:       net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
+		EthernetType: layers.EthernetTypeARP,
+	}
+}
+
+func makePacketARP(hw net.HardwareAddr, ip net.IP) *layers.ARP {
+	return &layers.ARP{
+		AddrType:          layers.LinkTypeEthernet,
+		Protocol:          layers.EthernetTypeIPv4,
+		HwAddressSize:     6,
+		ProtAddressSize:   4,
+		Operation:         layers.ARPRequest,
+		SourceHwAddress:   []byte(hw),
+		SourceProtAddress: []byte(ip),
+		DstHwAddress:      []byte{0, 0, 0, 0, 0, 0},
+	}
 }

discovery/port.go

@@ -2,6 +2,6 @@ package discovery
 
 import "git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
 
-func scanPort(host *model.Host, dp *model.DiscoveryPort, resultChan chan *model.Port, errChan chan error, doneChan chan<- struct{}) {
+func scanPort(host *model.Host, dp *model.DiscoveryPort, resultChan chan interface{}, errChan chan error, doneChan chan<- struct{}) {
 	doneChan <- struct{}{}
 }

discovery/service.go

@@ -2,6 +2,6 @@ package discovery
 
 import "git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
 
-func scanService(port *model.Port, ds *model.DiscoveryService, resultChan chan *model.Service, errChan chan error, doneChan chan<- struct{}) {
+func scanService(port *model.Port, ds *model.DiscoveryService, resultChan chan interface{}, errChan chan error, doneChan chan<- struct{}) {
 	doneChan <- struct{}{}
 }

discovery/zone.go

@@ -8,7 +8,7 @@ import (
 	"git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
 )
 
-func scanZone(dz *model.DiscoveryZone, resultChan chan *model.Zone, errChan chan error, doneChan chan<- struct{}) {
+func scanZone(dz *model.DiscoveryZone, resultChan chan interface{}, errChan chan error, doneChan chan<- struct{}) {
 	var err error
 	var ifaces []net.Interface
 	var addrs []net.Addr