143 lines
3.0 KiB
Go
143 lines
3.0 KiB
Go
// 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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// +build go1.16,!ios !go1.16,!darwin !go1.16,!arm64
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package portlist
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import (
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"sort"
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"strconv"
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"strings"
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)
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func parsePort(s string) int {
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// a.b.c.d:1234 or [a:b:c:d]:1234
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i1 := strings.LastIndexByte(s, ':')
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// a.b.c.d.1234 or [a:b:c:d].1234
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i2 := strings.LastIndexByte(s, '.')
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i := i1
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if i2 > i {
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i = i2
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}
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if i < 0 {
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// no match; weird
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return -1
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}
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portstr := s[i+1:]
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if portstr == "*" {
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return 0
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}
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port, err := strconv.ParseUint(portstr, 10, 16)
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if err != nil {
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// invalid port; weird
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return -1
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}
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return int(port)
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}
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func isLoopbackAddr(s string) bool {
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return strings.HasPrefix(s, "127.") ||
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strings.HasPrefix(s, "[::1]:") ||
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strings.HasPrefix(s, "::1.")
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}
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type nothing struct{}
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// Lowest common denominator parser for "netstat -na" format.
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// All of Linux, Windows, and macOS support -na and give similar-ish output
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// formats that we can parse without special detection logic.
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// Unfortunately, options to filter by proto or state are non-portable,
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// so we'll filter for ourselves.
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func parsePortsNetstat(output string) List {
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m := map[Port]nothing{}
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lines := strings.Split(string(output), "\n")
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var lastline string
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var lastport Port
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for _, line := range lines {
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trimline := strings.TrimSpace(line)
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cols := strings.Fields(trimline)
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if len(cols) < 1 {
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continue
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}
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protos := strings.ToLower(cols[0])
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var proto, laddr, raddr string
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if strings.HasPrefix(protos, "tcp") {
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if len(cols) < 4 {
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continue
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}
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proto = "tcp"
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laddr = cols[len(cols)-3]
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raddr = cols[len(cols)-2]
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state := cols[len(cols)-1]
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if !strings.HasPrefix(state, "LISTEN") {
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// not interested in non-listener sockets
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continue
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}
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if isLoopbackAddr(laddr) {
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// not interested in loopback-bound listeners
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continue
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}
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} else if strings.HasPrefix(protos, "udp") {
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if len(cols) < 3 {
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continue
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}
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proto = "udp"
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laddr = cols[len(cols)-2]
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raddr = cols[len(cols)-1]
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if isLoopbackAddr(laddr) {
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// not interested in loopback-bound listeners
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continue
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}
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} else if protos[0] == '[' && len(trimline) > 2 {
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// Windows: with netstat -nab, appends a line like:
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// [description]
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// after the port line.
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p := lastport
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delete(m, lastport)
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proc := trimline[1 : len(trimline)-1]
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if proc == "svchost.exe" && lastline != "" {
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p.Process = argvSubject(lastline)
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} else {
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p.Process = argvSubject(proc)
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}
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m[p] = nothing{}
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} else {
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// not interested in other protocols
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lastline = trimline
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continue
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}
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lport := parsePort(laddr)
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rport := parsePort(raddr)
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if rport != 0 || lport <= 0 {
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// not interested in "connected" sockets
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continue
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}
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p := Port{
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Proto: proto,
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Port: uint16(lport),
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}
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m[p] = nothing{}
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lastport = p
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lastline = ""
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}
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l := []Port{}
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for p := range m {
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l = append(l, p)
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}
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sort.Slice(l, func(i, j int) bool {
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return (&l[i]).lessThan(&l[j])
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})
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return l
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}
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