add support for internal ARP table

arp/arp.go

@@ -2,7 +2,6 @@
 package arp
 
 import (
-	"encoding/binary"
 	"net"
 	"sync"
 
@@ -11,7 +10,7 @@ import (
 )
 
 var (
-	table   map[uint32]net.HardwareAddr
+	table   = make(map[string]net.HardwareAddr)
 	tableMu sync.RWMutex
 )
 
@@ -20,26 +19,32 @@ var defaultSerializeOpts = gopacket.SerializeOptions{
 	ComputeChecksums: true,
 }
 
-func init() {
-	table = make(map[uint32]net.HardwareAddr)
+// Add adds a IP-MAC map to a runtime ARP table.
+func internalLookup(ip net.IP) (*net.HardwareAddr, bool) {
+	tableMu.Lock()
+	defer tableMu.Unlock()
+	if hwaddr, ok := table[ip.To4().String()]; ok {
+		return &hwaddr, true
+	}
+	return nil, false
 }
 
 // Add adds a IP-MAC map to a runtime ARP table.
 func Add(ip net.IP, hwaddr net.HardwareAddr) {
 	tableMu.Lock()
 	defer tableMu.Unlock()
-	table[binary.BigEndian.Uint32(ip)] = hwaddr
+	table[ip.To4().String()] = hwaddr
 }
 
 // Delete removes an IP from the runtime ARP table.
 func Delete(ip net.IP) {
 	tableMu.Lock()
 	defer tableMu.Unlock()
-	delete(table, binary.BigEndian.Uint32(ip))
+	delete(table, ip.To4().String())
 }
 
 // List returns the current runtime ARP table.
-func List() map[uint32]net.HardwareAddr {
+func List() map[string]net.HardwareAddr {
 	tableMu.RLock()
 	defer tableMu.RUnlock()
 	return table
@@ -54,16 +59,19 @@ type Address struct {
 
 // Lookup returns the Address given an IP, if the IP is not found within the
 // table, a lookup is attempted.
-func Lookup(ip uint32) (*Address, error) {
-	b := make([]byte, 4)
-	binary.BigEndian.PutUint32(b, ip)
-	if hwaddr, ok := table[ip]; ok {
+func Lookup(ip net.IP) (*Address, error) {
+	if hwaddr, ok := internalLookup(ip); ok {
 		return &Address{
-			IP:           net.IP(b),
-			HardwareAddr: hwaddr,
+			IP:           ip,
+			HardwareAddr: *hwaddr,
 		}, nil
 	}
-	return doARPLookup(net.IP(b).To4().String())
+
+	addr, err := doARPLookup(ip.To4().String())
+	if err == nil {
+		Add(addr.IP, addr.HardwareAddr)
+	}
+	return addr, err
 }
 
 // NewARPRequest creates a bew ARP packet of type "request.

arp/arp_darwin.go

@@ -39,8 +39,13 @@ func hexToInt(h string) uint8 {
 
 func doARPLookup(ip string) (*Address, error) {
 	ping := exec.Command("ping", "-c1", "-t1", ip)
-	ping.Run() // TODO: manually inject arp who has packet.
-	ping.Wait()
+	if err := ping.Start(); err != nil {
+		return nil, err
+	}
+
+	if err := ping.Wait(); err != nil {
+		return nil, err
+	}
 
 	cmd := exec.Command("arp", "-n", ip)
 	out, err := cmd.Output()

arp/arp_freebsd.go

@@ -20,8 +20,13 @@ func hexToInt(h string) uint8 {
 
 func doARPLookup(ip string) (*Address, error) {
 	ping := exec.Command("ping", "-c1", "-t1", ip)
-	ping.Run() // TODO: manually inject arp who has packet.
-	ping.Wait()
+	if err := ping.Start(); err != nil {
+		return nil, err
+	}
+
+	if err := ping.Wait(); err != nil {
+		return nil, err
+	}
 
 	cmd := exec.Command("arp", "-n", ip)
 	out, err := cmd.Output()

arp/arp_linux.go

@@ -15,7 +15,7 @@ var lineMatch = regexp.MustCompile(`([0-9\.]+)\s+dev\s+([^\s]+)\s+lladdr\s+([0-9
 func doARPLookup(ip string) (*Address, error) {
 
 	ping := exec.Command("ping", "-c1", "-t1", ip)
-	if err := ping.Run(); err != nil { // TODO: manually inject arp who has packet.
+	if err := ping.Start(); err != nil {
 		return nil, err
 	}
 
@@ -50,6 +50,7 @@ func doARPLookup(ip string) (*Address, error) {
 			HardwareAddr: macAddr,
 			Interface:    *iface,
 		}
+
 		return &localAddr, nil
 	}
 	return nil, errors.New("Lookup failed.")

arp/arp_test.go

@@ -1,14 +1,13 @@
 package arp
 
 import (
-	"encoding/binary"
 	"net"
 	"testing"
 )
 
 func SkipTestArp(t *testing.T) {
 	ip := net.IP{10, 0, 0, 1}
-	addr, err := Lookup(binary.BigEndian.Uint32(ip))
+	addr, err := Lookup(ip)
 	if err != nil {
 		t.Fatal(err)
 	}

arp/arp_windows.go

@@ -47,7 +47,13 @@ func winTable() map[string]string {
 
 func doARPLookup(ip string) (*Address, error) {
 	ping := exec.Command("cmd", "/C", "ping -n 1", ip)
-	ping.Run()
+	if err := ping.Start(); err != nil {
+		return nil, err
+	}
+
+	if err := ping.Wait(); err != nil {
+		return nil, err
+	}
 
 	arpAllTable := winTable()
 	if hwaddr, ok := arpAllTable[ip]; ok {

go.mod

@@ -1,9 +1,10 @@
 module github.com/malfunkt/arpfox
 
-go 1.12
+go 1.14
 
 require (
 	github.com/google/gopacket v1.1.17
 	github.com/malfunkt/iprange v0.9.0
-	github.com/pkg/errors v0.8.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/stretchr/testify v1.5.1 // indirect
 )

go.sum

@@ -1,11 +1,23 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/gopacket v1.1.17 h1:rMrlX2ZY2UbvT+sdz3+6J+pp2z+msCq9MxTU6ymxbBY=
 github.com/google/gopacket v1.1.17/go.mod h1:UdDNZ1OO62aGYVnPhxT1U6aI7ukYtA/kB8vaU0diBUM=
 github.com/malfunkt/iprange v0.9.0 h1:VCs0PKLUPotNVQTpVNszsut4lP7OCGNBwX+lOYBrnVQ=
 github.com/malfunkt/iprange v0.9.0/go.mod h1:TRGqO/f95gh3LOndUGTL46+W0GXA91WTqyZ0Quwvt4U=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
+github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67 h1:1Fzlr8kkDLQwqMP8GxrhptBLqZG/EDpiATneiZHY998=
 golang.org/x/sys v0.0.0-20190405154228-4b34438f7a67/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

main.go

@@ -23,7 +23,6 @@ package main
 
 import (
 	"bytes"
-	"encoding/binary"
 	"flag"
 	"fmt"
 	"log"
@@ -57,7 +56,7 @@ var (
 	flagInterface      = flag.String("i", defaultInterface(), `Network interface.`)
 	flagTarget         = flag.String("t", "", `Target host(s). Provide a single IP: "1.2.3.4", a CIDR block "1.2.3.0/24", an IP range: "1.2.3-7.4-12", an IP with a wildcard: "1.2.3.*", or a list with any combination: "1.2.3.4, 1.2.3.0/24, ..."`)
 	flagListInterfaces = flag.Bool("l", false, `List available interfaces and exit.`)
-	flagWaitInterval   = flag.Float64("w", 5.0, `Wait <w> seconds between every broadcast, <w> must be a value greater than 0.1.`)
+	flagWaitInterval   = flag.Float64("w", 2, `Wait <w> seconds between every broadcast, <w> must be a value greater than 0.1.`)
 	flagHelp           = flag.Bool("h", false, `Print usage instructions and exit.`)
 )
 
@@ -174,7 +173,7 @@ func main() {
 	go readARP(handler, stop, iface)
 
 	// Get original source
-	origSrc, err := arp.Lookup(binary.BigEndian.Uint32(hostIP))
+	origSrc, err := arp.Lookup(hostIP)
 	if err != nil {
 		log.Fatalf("Unable to lookup hw address for %s: %v", hostIP, err)
 	}
@@ -206,6 +205,7 @@ func cleanUpAndReARP(handler *pcap.Handle, targetAddrs []net.IP, src *arp.Addres
 
 func writeARP(handler *pcap.Handle, stop chan struct{}, targetAddrs []net.IP, src *arp.Address, waitInterval time.Duration) chan struct{} {
 	stoppedWriting := make(chan struct{})
+
 	go func(stoppedWriting chan struct{}) {
 		t := time.NewTicker(waitInterval)
 		for {
@@ -216,7 +216,7 @@ func writeARP(handler *pcap.Handle, stop chan struct{}, targetAddrs []net.IP, sr
 			default:
 				<-t.C
 				for _, ip := range targetAddrs {
-					arpAddr, err := arp.Lookup(binary.BigEndian.Uint32(ip))
+					arpAddr, err := arp.Lookup(ip)
 					if err != nil {
 						log.Printf("Could not retrieve %v's MAC address: %v", ip, err)
 						continue
@@ -225,6 +225,7 @@ func writeARP(handler *pcap.Handle, stop chan struct{}, targetAddrs []net.IP, sr
 						IP:           ip,
 						HardwareAddr: arpAddr.HardwareAddr,
 					}
+
 					buf, err := arp.NewARPRequest(src, dst)
 					if err != nil {
 						log.Print("NewARPRequest: ", err)
@@ -237,6 +238,7 @@ func writeARP(handler *pcap.Handle, stop chan struct{}, targetAddrs []net.IP, sr
 			}
 		}
 	}(stoppedWriting)
+
 	return stoppedWriting
 }