DHCP Client with fake Mac Address

dhcpclient.go

package main

import (
	"flag"
	"log"
	"net"

	"github.com/davecgh/go-spew/spew"
	"github.com/insomniacslk/dhcp/dhcpv4"
	client4 "github.com/insomniacslk/dhcp/dhcpv4/client4"
	"github.com/insomniacslk/dhcp/netboot"
)

var (
	ifname  = flag.String("i", "eth0", "Interface name")
	macAddr = flag.String("m", "ba:ba:ca:ba:ba:ca", "Fake Mac Address")
)

func main() {
	flag.Parse()
	var (
		err      error
		bootconf *netboot.BootConf
	)
	bootconf, err = dhclient4(*ifname, 3, true)
	if err != nil {
		log.Fatal(err)
	}
	spew.Dump(bootconf)
}

func dhclient4(ifname string, attempts int, verbose bool) (*netboot.BootConf, error) {
	if attempts < 1 {
		attempts = 1
	}
	client := client4.NewClient()
	var (
		conv []*dhcpv4.DHCPv4
		err  error
	)

	newMac, err := net.ParseMAC(*macAddr)
	if err != nil {
		return nil, err
	}

	for attempt := 0; attempt < attempts; attempt++ {
		log.Printf("Attempt %d of %d", attempt+1, attempts)
		conv, err = client.Exchange(ifname, dhcpv4.WithHwAddr(newMac), dhcpv4.WithBroadcast(true))
		if err != nil && attempt < attempts {
			log.Printf("Error: %v", err)
			continue
		}
		break
	}
	if verbose {
		for _, m := range conv {
			log.Print(m.Summary())
		}
	}
	if err != nil {
		return nil, err
	}
	// extract the network configuration
	netconf, err := netboot.ConversationToNetconfv4(conv)
	return netconf, err
}