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v-byte-cpuv-byte-cpu
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Add ARP scan
1 parent 21483d5 commit f853373

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‎.gitignore‎

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sx

‎README.md‎

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# sx
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## Purpose
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The goal of this project is to create the fastest network scanner with clean and simple code.
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Right now, only ARP scan is supported.
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## Building
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From the root of the source tree, run:
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```
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go build
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```
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## Using
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```
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./sx help
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```

‎command/arp.go‎

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package command
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import (
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"bufio"
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"context"
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"errors"
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"net"
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"os"
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"os/signal"
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"strings"
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"sync"
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"time"
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"github.com/spf13/cobra"
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"github.com/v-byte-cpu/sx/pkg/ip"
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"github.com/v-byte-cpu/sx/pkg/packet/afpacket"
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"github.com/v-byte-cpu/sx/pkg/scan"
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"github.com/v-byte-cpu/sx/pkg/scan/arp"
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"go.uber.org/zap"
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)
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var errSrcIP = errors.New("invalid source IP")
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var interfaceFlag string
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var srcIPFlag string
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var srcMACFlag string
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func init() {
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arpCmd.Flags().StringVarP(&interfaceFlag, "iface", "i", "", "set interface to send/receive packets")
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arpCmd.Flags().StringVar(&srcIPFlag, "srcip", "", "set source IP address for generated packets")
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arpCmd.Flags().StringVar(&srcMACFlag, "srcmac", "", "set source MAC address for generated packets")
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rootCmd.AddCommand(arpCmd)
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}
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var arpCmd = &cobra.Command{
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Use: "arp [flags] subnet",
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Example: strings.Join([]string{"arp 192.168.0.1/24", "arp 10.0.0.1"}, "\n"),
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Short: "Perform ARP scan",
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Args: func(cmd *cobra.Command, args []string) error {
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if len(args) != 1 {
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return errors.New("requires one ip subnet argument")
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}
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return nil
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},
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RunE: func(cmd *cobra.Command, args []string) (err error) {
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dstSubnet, err := ip.ParseIPNet(args[0])
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if err != nil {
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return err
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}
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var iface *net.Interface
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var srcIP net.IP
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if len(interfaceFlag) > 0 {
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if iface, err = net.InterfaceByName(interfaceFlag); err != nil {
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return err
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}
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} else {
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if iface, srcIP, err = ip.GetSubnetInterface(dstSubnet); err != nil {
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return err
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}
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}
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if len(srcIPFlag) > 0 {
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if srcIP = net.ParseIP(srcIPFlag); srcIP == nil {
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return errSrcIP
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}
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}
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srcMAC := iface.HardwareAddr
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if len(srcMACFlag) > 0 {
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if srcMAC, err = net.ParseMAC(srcMACFlag); err != nil {
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return err
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}
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}
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r := &scan.Range{Subnet: dstSubnet, Interface: iface, SrcIP: srcIP, SrcMAC: srcMAC}
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return startEngine(r)
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},
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}
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func startEngine(r *scan.Range) error {
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bw := bufio.NewWriter(os.Stdout)
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defer bw.Flush()
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logger, err := zap.NewProduction()
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if err != nil {
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return err
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}
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ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
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defer cancel()
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// setup network interface to read/write packets
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rw, err := afpacket.NewPacketSource(r.Interface.Name)
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if err != nil {
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return err
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}
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defer rw.Close()
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err = rw.SetBPFFilter(arp.BPFFilter(r))
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if err != nil {
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return err
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}
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m := arp.NewScanMethod(ctx)
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// setup result logging
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var wg sync.WaitGroup
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wg.Add(1)
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go func() {
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defer wg.Done()
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for result := range m.Results() {
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// TODO extract it
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if jsonFlag {
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data, err := result.MarshalJSON()
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if err != nil {
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logger.Error("arp", zap.Error(err))
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}
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bw.Write(data)
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} else {
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bw.WriteString(result.String())
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}
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bw.WriteByte('\n')
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}
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}()
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// start scan
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engine := scan.SetupEngine(rw, m)
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done, errc := engine.Start(ctx, r)
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go func() {
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defer cancel()
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<-done
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<-time.After(300 * time.Millisecond)
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}()
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// error logging
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wg.Add(1)
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go func() {
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defer wg.Done()
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for err := range errc {
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logger.Error("arp", zap.Error(err))
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}
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}()
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wg.Wait()
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return nil
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}

‎command/root.go‎

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package command
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import (
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"os"
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"github.com/spf13/cobra"
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)
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var rootCmd = &cobra.Command{
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Use: "sx",
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Short: "Fast, modern, easy-to-use network scanner",
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Version: "0.1.0",
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}
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var jsonFlag bool
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func init() {
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rootCmd.PersistentFlags().BoolVar(&jsonFlag, "json", false, "enable JSON output")
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}
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func Main() {
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if err := rootCmd.Execute(); err != nil {
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os.Exit(1)
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}
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}

‎go.mod‎

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module github.com/v-byte-cpu/sx
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go 1.15
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require (
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github.com/golang/mock v1.5.0
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github.com/google/gopacket v1.1.20-0.20210304165259-20562ffb40f8
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github.com/google/wire v0.5.0
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github.com/mailru/easyjson v0.7.7
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github.com/spf13/cobra v1.1.3
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github.com/stretchr/testify v1.7.0
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go.uber.org/multierr v1.6.0 // indirect
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go.uber.org/zap v1.16.0
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golang.org/x/net v0.0.0-20210226172049-e18ecbb05110
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)

‎go.sum‎

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‎main.go‎

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package main
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import "github.com/v-byte-cpu/sx/command"
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func main() {
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command.Main()
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}

‎pkg/ip/ip.go‎

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package ip
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import (
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"errors"
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"net"
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)
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var (
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ErrInvalidAddr = errors.New("invalid IP subnet/host")
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ErrSubnetInterface = errors.New("no directly connected interfaces to destination subnet")
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)
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func Inc(ip net.IP) {
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for j := len(ip) - 1; j >= 0; j-- {
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ip[j]++
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if ip[j] > 0 {
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break
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}
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}
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}
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func DupIP(ip net.IP) net.IP {
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dup := make([]byte, 4)
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copy(dup, ip.To4())
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return dup
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}
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func ParseIPNet(subnet string) (*net.IPNet, error) {
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_, result, err := net.ParseCIDR(subnet)
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if err == nil {
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return result, err
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}
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// try to parse host IP address instead
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ipAddr := net.ParseIP(subnet)
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if ipAddr == nil {
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return nil, ErrInvalidAddr
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}
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return &net.IPNet{IP: ipAddr.To4(), Mask: net.CIDRMask(32, 32)}, nil
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}
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func GetSubnetInterface(dstSubnet *net.IPNet) (*net.Interface, net.IP, error) {
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dstSubnetIP := dstSubnet.IP.Mask(dstSubnet.Mask)
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, nil, err
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}
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for _, iface := range ifaces {
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addrs, err := iface.Addrs()
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if err != nil {
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return nil, nil, err
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}
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for _, addr := range addrs {
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if ipnet, ok := addr.(*net.IPNet); ok && ipnet.Contains(dstSubnetIP) {
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return &iface, ipnet.IP.To4(), nil
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}
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}
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}
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return nil, nil, ErrSubnetInterface
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}

‎pkg/ip/ip_test.go‎

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package ip
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import (
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"net"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestInc(t *testing.T) {
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t.Parallel()
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tests := []struct {
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name string
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input net.IP
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expected net.IP
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}{
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{
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name: "ZeroNet",
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input: net.IPv4(0, 0, 0, 0),
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expected: net.IPv4(0, 0, 0, 1),
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},
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{
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name: "Inc3rd",
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input: net.IPv4(1, 1, 0, 255),
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expected: net.IPv4(1, 1, 1, 0),
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},
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{
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name: "Inc2nd",
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input: net.IPv4(1, 1, 255, 255),
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expected: net.IPv4(1, 2, 0, 0),
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},
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{
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name: "Inc1st",
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input: net.IPv4(1, 255, 255, 255),
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expected: net.IPv4(2, 0, 0, 0),
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},
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}
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for _, vtt := range tests {
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tt := vtt
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t.Run(tt.name, func(t *testing.T) {
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t.Parallel()
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Inc(tt.input)
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assert.Equal(t, tt.expected, tt.input)
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})
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}
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}
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func TestDupIP(t *testing.T) {
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t.Parallel()
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ipAddr := net.IPv4(192, 168, 0, 1).To4()
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dupAddr := DupIP(ipAddr)
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assert.Equal(t, ipAddr, dupAddr)
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dupAddr[3]++
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assert.Equal(t, net.IPv4(192, 168, 0, 1).To4(), ipAddr)
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}
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func TestParseIPNetWithError(t *testing.T) {
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t.Parallel()
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_, err := ParseIPNet("")
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assert.Error(t, err)
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}
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func TestParseIPNet(t *testing.T) {
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t.Parallel()
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tests := []struct {
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name string
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in string
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expected *net.IPNet
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}{
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{
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name: "subnet",
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in: "192.168.0.1/24",
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expected: &net.IPNet{
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IP: net.IPv4(192, 168, 0, 0).To4(),
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Mask: net.CIDRMask(24, 32),
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},
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},
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{
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name: "host",
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in: "10.0.0.1",
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expected: &net.IPNet{
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IP: net.IPv4(10, 0, 0, 1).To4(),
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Mask: net.CIDRMask(32, 32),
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},
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},
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}
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for _, vtt := range tests {
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tt := vtt
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t.Run(tt.name, func(t *testing.T) {
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result, err := ParseIPNet(tt.in)
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assert.NoError(t, err)
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assert.Equal(t, tt.expected, result)
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})
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}
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}

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