mirror of https://github.com/tailscale/tailscale/
net/netns: add windows support.
Also remove rebinding logic from the windows router. Magicsock will instead rebind based on link change signals. Signed-off-by: David Anderson <danderson@tailscale.com>pull/763/head
David Anderson
4 years ago
committed by
Dave Anderson
parent
3f4d93feb2
commit
8f5b52e571
@ -0,0 +1,123 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package netns
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import (
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"encoding/binary"
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"syscall"
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"unsafe"
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"github.com/tailscale/winipcfg-go"
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"golang.org/x/sys/windows"
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"tailscale.com/net/interfaces"
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)
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// control binds c to the Windows interface that holds a default
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// route, and is not the Tailscale WinTun interface.
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func control(network, address string, c syscall.RawConn) error {
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canV4, canV6 := false, false
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switch network {
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case "tcp", "udp":
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canV4, canV6 = true, true
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case "tcp4", "udp4":
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canV4 = true
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case "tcp6", "udp6":
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canV6 = true
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}
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if canV4 {
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if4, err := getDefaultInterface(winipcfg.AF_INET)
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if err != nil {
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return err
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}
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if err := bindSocket4(c, if4); err != nil {
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return err
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}
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}
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if canV6 {
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if6, err := getDefaultInterface(winipcfg.AF_INET6)
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if err != nil {
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return err
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}
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if err := bindSocket6(c, if6); err != nil {
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return err
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}
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}
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return nil
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}
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// getDefaultInterface returns the index of the interface that has the
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// non-Tailscale default route for the given address family.
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func getDefaultInterface(family winipcfg.AddressFamily) (ifidx uint32, err error) {
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ifs, err := interfaces.NonTailscaleMTUs()
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if err != nil {
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return 0, err
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}
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routes, err := winipcfg.GetRoutes(family)
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if err != nil {
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return 0, err
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}
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bestMetric := ^uint32(0)
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// The zero index means "unspecified". If we end up passing zero
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// to bindSocket*(), it unsets the binding and lets the socket
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// behave as normal again, which is what we want if there's no
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// default route we can use.
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var index uint32
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for _, route := range routes {
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if route.DestinationPrefix.PrefixLength != 0 || ifs[route.InterfaceLuid] == 0 {
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continue
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}
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if route.Metric < bestMetric {
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bestMetric = route.Metric
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index = route.InterfaceIndex
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}
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}
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return index, nil
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}
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const sockoptBoundInterface = 31
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// bindSocket4 binds the given RawConn to the network interface with
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// index ifidx, for IPv4 traffic only.
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func bindSocket4(c syscall.RawConn, ifidx uint32) error {
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// For v4 the interface index must be passed as a big-endian
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// integer, regardless of platform endianness.
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index := nativeToBigEndian(ifidx)
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var controlErr error
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err := c.Control(func(fd uintptr) {
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controlErr = windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IP, sockoptBoundInterface, int(index))
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})
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if err != nil {
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return err
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}
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return controlErr
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}
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// bindSocket6 binds the given RawConn to the network interface with
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// index ifidx, for IPv6 traffic only.
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func bindSocket6(c syscall.RawConn, ifidx uint32) error {
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var controlErr error
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err := c.Control(func(fd uintptr) {
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controlErr = windows.SetsockoptInt(windows.Handle(fd), windows.IPPROTO_IPV6, sockoptBoundInterface, int(ifidx))
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})
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if err != nil {
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return err
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}
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return controlErr
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}
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// nativeToBigEndian returns i converted into big-endian
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// representation, suitable for passing to Windows APIs that require a
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// mangled uint32.
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func nativeToBigEndian(i uint32) uint32 {
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var b [4]byte
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binary.BigEndian.PutUint32(b[:], i)
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return *(*uint32)(unsafe.Pointer(&b[0]))
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}
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@ -0,0 +1,11 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package tsconst exports some constants used elsewhere in the
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// codebase.
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package tsconst
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// WintunInterfaceDesc is the description attached to Tailscale
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// interfaces on Windows. This is set by our modified WinTun driver.
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const WintunInterfaceDesc = "Tailscale Tunnel"
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