package iface import ( "errors" "net" "net/netip" "time" "github.com/Dreamacro/clash/common/singledo" ) type Interface struct { Index int Name string Addrs []*netip.Prefix HardwareAddr net.HardwareAddr } var ( ErrIfaceNotFound = errors.New("interface not found") ErrAddrNotFound = errors.New("addr not found") ) var interfaces = singledo.NewSingle(time.Second * 20) func ResolveInterface(name string) (*Interface, error) { value, err, _ := interfaces.Do(func() (any, error) { ifaces, err := net.Interfaces() if err != nil { return nil, err } r := map[string]*Interface{} for _, iface := range ifaces { addrs, err := iface.Addrs() if err != nil { continue } ipNets := make([]*netip.Prefix, 0, len(addrs)) for _, addr := range addrs { ipNet := addr.(*net.IPNet) ip, _ := netip.AddrFromSlice(ipNet.IP) ones, bits := ipNet.Mask.Size() if bits == 32 { ip = ip.Unmap() } pf := netip.PrefixFrom(ip, ones) ipNets = append(ipNets, &pf) } r[iface.Name] = &Interface{ Index: iface.Index, Name: iface.Name, Addrs: ipNets, HardwareAddr: iface.HardwareAddr, } } return r, nil }) if err != nil { return nil, err } ifaces := value.(map[string]*Interface) iface, ok := ifaces[name] if !ok { return nil, ErrIfaceNotFound } return iface, nil } func FlushCache() { interfaces.Reset() } func (iface *Interface) PickIPv4Addr(destination netip.Addr) (*netip.Prefix, error) { return iface.pickIPAddr(destination, func(addr *netip.Prefix) bool { return addr.Addr().Is4() }) } func (iface *Interface) PickIPv6Addr(destination netip.Addr) (*netip.Prefix, error) { return iface.pickIPAddr(destination, func(addr *netip.Prefix) bool { return addr.Addr().Is6() }) } func (iface *Interface) pickIPAddr(destination netip.Addr, accept func(addr *netip.Prefix) bool) (*netip.Prefix, error) { var fallback *netip.Prefix for _, addr := range iface.Addrs { if !accept(addr) { continue } if fallback == nil && !addr.Addr().IsLinkLocalUnicast() { fallback = addr if !destination.IsValid() { break } } if destination.IsValid() && addr.Contains(destination) { return addr, nil } } if fallback == nil { return nil, ErrAddrNotFound } return fallback, nil }