//go:build linux || (windows && amd64)

package agent

import (

"sync"

"time"

"github.com/cakturk/go-netstat/netstat"

"golang.org/x/xerrors"

"github.com/coder/coder/v2/codersdk"

)

type osListeningPortsGetter struct {

cacheDuration time.Duration

mut sync.Mutex

ports []codersdk.WorkspaceAgentListeningPort

mtime time.Time

}

func (lp *osListeningPortsGetter) GetListeningPorts() ([]codersdk.WorkspaceAgentListeningPort, error) {

lp.mut.Lock()

defer lp.mut.Unlock()

if time.Since(lp.mtime) < lp.cacheDuration {

// copy

ports := make([]codersdk.WorkspaceAgentListeningPort, len(lp.ports))

copy(ports, lp.ports)

return ports, nil

}

acceptListening := func(s *netstat.SockTabEntry) bool {

return s.State == netstat.Listen

}

tabs, err := netstat.TCPSocks(acceptListening)

if err != nil {

return nil, xerrors.Errorf("scan listening ports: %w", err)

}

// Include IPv6 listeners too. Many dev servers (e.g. Next.js, Node's

// default http.Server) bind to the IPv6 wildcard address "::", which is

// a dual-stack socket that also accepts IPv4 connections, but only shows

// up in the IPv6 socket table (/proc/net/tcp6), not /proc/net/tcp.

//

// The IPv6 scan fails on systems with IPv6 disabled (e.g. missing

// /proc/net/tcp6 on Linux). Fall back to the IPv4 results instead of

// failing the whole scan, otherwise the ports UI breaks entirely on

// such systems.

tabs6, err := netstat.TCP6Socks(acceptListening)

if err == nil {

tabs = append(tabs, tabs6...)

}

seen := make(map[uint16]struct{}, len(tabs))

ports := []codersdk.WorkspaceAgentListeningPort{}

for _, tab := range tabs {

if tab.LocalAddr == nil {

continue

}

// Don't include ports that we've already seen. This can happen on

// Windows, and maybe on Linux if you're using a shared listener socket.

if _, ok := seen[tab.LocalAddr.Port]; ok {

continue

}

seen[tab.LocalAddr.Port] = struct{}{}

procName := ""

if tab.Process != nil {

procName = tab.Process.Name

}

ports = append(ports, codersdk.WorkspaceAgentListeningPort{

ProcessName: procName,

Network: "tcp",

Port: tab.LocalAddr.Port,

})

}

lp.ports = ports

lp.mtime = time.Now()

// copy

ports = make([]codersdk.WorkspaceAgentListeningPort, len(lp.ports))

copy(ports, lp.ports)

return ports, nil

}