使用 krolaw/dhcp4 库获取 DHCP 服务器 IPv4 和 IPv6 地址

以下是一个示例程序，使用 krolaw/dhcp4 库获取客户端的 IPv4 和 IPv6 地址：

package main

import (
	"fmt"
	"net"

	"github.com/krolaw/dhcp4"
)

func main() {
	// 客户端地址和网卡名
	clientAddr := net.ParseIP('192.168.1.100')
	clientHwAddr, _ := net.ParseMAC('00:11:22:33:44:55')

	// DHCP 请求
	requestPacket, err := dhcp4.NewRequestPacket(dhcp4.BootRequest)
	if err != nil {
		fmt.Println('Failed to create DHCP request packet:', err)
		return
	}
	requestPacket.AddOption(dhcp4.OptParameterRequestList,
		[]byte{dhcp4.OptionIPAddressLeaseTime, dhcp4.OptionRouter, dhcp4.OptionDNS, dhcp4.OptionDomainNameServer})
	requestPacket.AddOption(dhcp4.OptDHCPMessage, []byte{byte(dhcp4.DHCPDiscover)})
	requestPacket.AddOption(dhcp4.OptClientIdentifier, clientHwAddr)
	requestPacket.AddOption(dhcp4.OptRequestedIPAddress, clientAddr)

	// 发送 DHCP 请求并等待响应
	responsePacket, err := dhcp4.SendRequestPacket(requestPacket, 'udp4', '255.255.255.255:67', '255.255.255.255:68', 5*time.Second)
	if err != nil {
		fmt.Println('Failed to send DHCP request:', err)
		return
	}

	// 解析响应
	leaseTime, _ := responsePacket.GetOptionValue(dhcp4.OptionIPAddressLeaseTime)
	routerIPs, _ := responsePacket.GetOptionValue(dhcp4.OptionRouter)
	dnsIPs, _ := responsePacket.GetOptionValue(dhcp4.OptionDNS)
	domainNameServers, _ := responsePacket.GetOptionValue(dhcp4.OptionDomainNameServer)

	// 输出 IPv4 地址和 IPv6 地址
	fmt.Println('IPv4 address:', clientAddr)
	if len(routerIPs) > 0 {
		fmt.Println('IPv6 address:', net.ParseIP(string(routerIPs)))
	}
}

**注意：**这个示例程序只能获取 IPv6 地址，如果服务器没有配置 IPv6 地址，将无法获取。