tailscale/portlist/portlist_windows.go

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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package portlist
import (
"time"
"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 uint32
}
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: uint32(e.Pid),
}
pm, ok := im.known[fp]
if ok {
pm.keep = true
continue
}
var process string
if e.OSMetadata != nil {
if module, err := e.OSMetadata.GetModule(); err == nil {
process = module
}
}
pm = &portMeta{
keep: true,
port: Port{
Proto: "tcp",
Port: e.Local.Port(),
Process: process,
},
}
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
}