sing-box/common/tun/tun_linux.go

package tun

import (
	"net/netip"

	"github.com/vishvananda/netlink"
	"gvisor.dev/gvisor/pkg/tcpip/link/tun"
)

func Open(name string) (uintptr, error) {
	tunFd, err := tun.Open(name)
	if err != nil {
		return 0, err
	}
	return uintptr(tunFd), nil
}

func Configure(name string, inet4Address netip.Prefix, inet6Address netip.Prefix, mtu uint32) error {
	tunLink, err := netlink.LinkByName(name)
	if err != nil {
		return err
	}

	if inet4Address.IsValid() {
		addr4, _ := netlink.ParseAddr(inet4Address.String())
		err = netlink.AddrAdd(tunLink, addr4)
		if err != nil {
			return err
		}
	}

	if inet6Address.IsValid() {
		addr6, _ := netlink.ParseAddr(inet6Address.String())
		err = netlink.AddrAdd(tunLink, addr6)
		if err != nil {
			return err
		}
	}

	err = netlink.LinkSetMTU(tunLink, int(mtu))
	if err != nil {
		return err
	}

	err = netlink.LinkSetUp(tunLink)
	if err != nil {
		return err
	}

	return nil
}