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iface.go
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iface.go
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package iface
import (
"errors"
"net"
"net/netip"
"time"
"github.com/yaling888/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[map[string]*Interface](time.Second * 20)
func ResolveInterface(name string) (*Interface, error) {
value, err, _ := interfaces.Do(func() (map[string]*Interface, 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
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
}