tailscale/portlist/portlist_windows.go
Brad Fitzpatrick 21ef7e5c35 portlist: add macOS osImpl, finish migration to new style
Previously:

* 036f70b7b4 for linux
* 35bee36549 for windows

This does macOS.

And removes all the compat code for the old style. (e.g. iOS, js are
no longer mentioned; all platforms without implementations just
default to not doing anything)

One possible regression is that platforms without explicit
implementations previously tried to do the "netstat -na" style to get
open ports (but not process names). Maybe that worked on FreeBSD and
OpenBSD previously, but nobody ever really tested it. And it was kinda
useless without associated process names. So better off removing those
for now until they get a good implementation.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2022-11-04 10:58:23 -07:00

121 lines
2.5 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package portlist
import (
"path/filepath"
"strings"
"syscall"
"time"
"golang.org/x/sys/windows"
"tailscale.com/net/netstat"
)
func init() {
newOSImpl = newWindowsImpl
// The portlist poller used to fork on Windows, which is insanely expensive,
// so historically we only did this every 5 seconds on Windows. Maybe we
// could reduce it down to 1 seconds like Linux, but nobody's benchmarked as
// of 2022-11-04.
pollInterval = 5 * time.Second
}
type famPort struct {
proto string
port uint16
pid uintptr
}
type windowsImpl struct {
known map[famPort]*portMeta // inode string => metadata
}
type portMeta struct {
port Port
keep bool
}
func newWindowsImpl() osImpl {
return &windowsImpl{
known: map[famPort]*portMeta{},
}
}
func (*windowsImpl) Close() error { return nil }
func (im *windowsImpl) AppendListeningPorts(base []Port) ([]Port, error) {
// TODO(bradfitz): netstat.Get makes a bunch of garbage. Add an Append-style
// API to that package instead/additionally.
tab, err := netstat.Get()
if err != nil {
return nil, err
}
for _, pm := range im.known {
pm.keep = false
}
ret := base
for _, e := range tab.Entries {
if e.State != "LISTEN" {
continue
}
if !e.Local.Addr().IsUnspecified() {
continue
}
fp := famPort{
proto: "tcp", // TODO(bradfitz): UDP too; add to netstat
port: e.Local.Port(),
pid: uintptr(e.Pid),
}
pm, ok := im.known[fp]
if ok {
pm.keep = true
continue
}
pm = &portMeta{
keep: true,
port: Port{
Proto: "tcp",
Port: e.Local.Port(),
Process: procNameOfPid(e.Pid),
},
}
im.known[fp] = pm
}
for k, m := range im.known {
if !m.keep {
delete(im.known, k)
continue
}
ret = append(ret, m.port)
}
return sortAndDedup(ret), nil
}
func procNameOfPid(pid int) string {
const da = windows.PROCESS_QUERY_LIMITED_INFORMATION
h, err := syscall.OpenProcess(da, false, uint32(pid))
if err != nil {
return ""
}
defer syscall.CloseHandle(h)
var buf [512]uint16
var size = uint32(len(buf))
if err := windows.QueryFullProcessImageName(windows.Handle(h), 0, &buf[0], &size); err != nil {
return ""
}
name := filepath.Base(windows.UTF16ToString(buf[:]))
if name == "." {
return ""
}
name = strings.TrimSuffix(name, ".exe")
name = strings.TrimSuffix(name, ".EXE")
return name
}