Clash.Meta/component/dhcp/conn.go

package dhcp

import (
	"context"
	"net"
	"net/netip"
	"runtime"

	"github.com/metacubex/mihomo/component/dialer"
)

func ListenDHCPClient(ctx context.Context, ifaceName string) (net.PacketConn, error) {
	listenAddr := "0.0.0.0:68"
	if runtime.GOOS == "linux" || runtime.GOOS == "android" {
		listenAddr = "255.255.255.255:68"
	}

	options := []dialer.Option{
		dialer.WithInterface(ifaceName),
		dialer.WithAddrReuse(true),
	}

	// fallback bind on windows, because syscall bind can not receive broadcast
	if runtime.GOOS == "windows" {
		options = append(options, dialer.WithFallbackBind(true))
	}

	return dialer.ListenPacket(ctx, "udp4", listenAddr, netip.AddrPortFrom(netip.AddrFrom4([4]byte{255, 255, 255, 255}), 67), options...)
}