net/interfaces, net/netns: move default route interface code to interfaces

To populate interfaces.State.DefaultRouteInterface.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
pull/782/head
Brad Fitzpatrick 4 years ago
parent fda9dc8815
commit 8893c2ee78

@ -2,7 +2,7 @@
// Use of this source code is governed by a BSD-style // Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file. // license that can be found in the LICENSE file.
// +build !linux // +build !linux,!windows
package interfaces package interfaces

@ -5,6 +5,7 @@
package interfaces package interfaces
import ( import (
"fmt"
"os/exec" "os/exec"
"syscall" "syscall"
@ -77,18 +78,73 @@ func likelyHomeRouterIPWindows() (ret netaddr.IP, ok bool) {
// NonTailscaleMTUs returns a map of interface LUID to interface MTU, // NonTailscaleMTUs returns a map of interface LUID to interface MTU,
// for all interfaces except Tailscale tunnels. // for all interfaces except Tailscale tunnels.
func NonTailscaleMTUs() (map[uint64]uint32, error) { func NonTailscaleMTUs() (map[uint64]uint32, error) {
ifs, err := winipcfg.GetInterfaces() mtus := map[uint64]uint32{}
ifs, err := NonTailscaleInterfaces()
for luid, iface := range ifs {
mtus[luid] = iface.Mtu
}
return mtus, err
}
// NonTailscaleInterfaces returns a map of interface LUID to interface
// for all interfaces except Tailscale tunnels.
func NonTailscaleInterfaces() (map[uint64]*winipcfg.Interface, error) {
ifs, err := winipcfg.GetInterfacesEx(&winipcfg.GetAdapterAddressesFlags{
GAA_FLAG_INCLUDE_ALL_INTERFACES: true,
})
if err != nil { if err != nil {
return nil, err return nil, err
} }
ret := map[uint64]uint32{} ret := map[uint64]*winipcfg.Interface{}
for _, iface := range ifs { for _, iface := range ifs {
if iface.Description == tsconst.WintunInterfaceDesc { if iface.Description == tsconst.WintunInterfaceDesc {
continue continue
} }
ret[iface.Luid] = iface.Mtu ret[iface.Luid] = iface
} }
return ret, nil return ret, nil
} }
// GetWindowsDefault returns the interface that has the non-Tailscale
// default route for the given address family.
//
// It returns (nil, nil) if no interface is found.
func GetWindowsDefault(family winipcfg.AddressFamily) (*winipcfg.Interface, error) {
ifs, err := NonTailscaleInterfaces()
if err != nil {
return nil, err
}
routes, err := winipcfg.GetRoutes(family)
if err != nil {
return nil, err
}
bestMetric := ^uint32(0)
var bestIface *winipcfg.Interface
for _, route := range routes {
iface := ifs[route.InterfaceLuid]
if route.DestinationPrefix.PrefixLength != 0 || iface == nil {
continue
}
if iface.OperStatus == winipcfg.IfOperStatusUp && route.Metric < bestMetric {
bestMetric = route.Metric
bestIface = iface
}
}
return bestIface, nil
}
func DefaultRouteInterface() (string, error) {
iface, err := GetWindowsDefault(winipcfg.AF_INET)
if err != nil {
return "", err
}
if iface == nil {
return "(none)", nil
}
return fmt.Sprintf("%s (%s)", iface.FriendlyName, iface.Description), nil
}

@ -14,6 +14,17 @@ import (
"tailscale.com/net/interfaces" "tailscale.com/net/interfaces"
) )
func interfaceIndex(iface *winipcfg.Interface) uint32 {
if iface == nil {
// The zero ifidx means "unspecified". If we end up passing zero
// to bindSocket*(), it unsets the binding and lets the socket
// behave as normal again, which is what we want if there's no
// default route we can use.
return 0
}
return iface.Index
}
// control binds c to the Windows interface that holds a default // control binds c to the Windows interface that holds a default
// route, and is not the Tailscale WinTun interface. // route, and is not the Tailscale WinTun interface.
func control(network, address string, c syscall.RawConn) error { func control(network, address string, c syscall.RawConn) error {
@ -28,21 +39,21 @@ func control(network, address string, c syscall.RawConn) error {
} }
if canV4 { if canV4 {
if4, err := getDefaultInterface(winipcfg.AF_INET) iface, err := interfaces.GetWindowsDefault(winipcfg.AF_INET)
if err != nil { if err != nil {
return err return err
} }
if err := bindSocket4(c, if4); err != nil { if err := bindSocket4(c, interfaceIndex(iface)); err != nil {
return err return err
} }
} }
if canV6 { if canV6 {
if6, err := getDefaultInterface(winipcfg.AF_INET6) iface, err := interfaces.GetWindowsDefault(winipcfg.AF_INET6)
if err != nil { if err != nil {
return err return err
} }
if err := bindSocket6(c, if6); err != nil { if err := bindSocket6(c, interfaceIndex(iface)); err != nil {
return err return err
} }
} }
@ -50,38 +61,6 @@ func control(network, address string, c syscall.RawConn) error {
return nil return nil
} }
// getDefaultInterface returns the index of the interface that has the
// non-Tailscale default route for the given address family.
func getDefaultInterface(family winipcfg.AddressFamily) (ifidx uint32, err error) {
ifs, err := interfaces.NonTailscaleMTUs()
if err != nil {
return 0, err
}
routes, err := winipcfg.GetRoutes(family)
if err != nil {
return 0, err
}
bestMetric := ^uint32(0)
// The zero index means "unspecified". If we end up passing zero
// to bindSocket*(), it unsets the binding and lets the socket
// behave as normal again, which is what we want if there's no
// default route we can use.
var index uint32
for _, route := range routes {
if route.DestinationPrefix.PrefixLength != 0 || ifs[route.InterfaceLuid] == 0 {
continue
}
if route.Metric < bestMetric {
bestMetric = route.Metric
index = route.InterfaceIndex
}
}
return index, nil
}
// sockoptBoundInterface is the value of IP_UNICAST_IF and IPV6_UNICAST_IF. // sockoptBoundInterface is the value of IP_UNICAST_IF and IPV6_UNICAST_IF.
// //
// See https://docs.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options // See https://docs.microsoft.com/en-us/windows/win32/winsock/ipproto-ip-socket-options

Loading…
Cancel
Save