1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
// 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.
// +build go1.16,!ios !go1.16,!darwin !go1.16,!arm64
package portlist
import (
"sort"
"strconv"
"strings"
)
func parsePort(s string) int {
// a.b.c.d:1234 or [a:b:c:d]:1234
i1 := strings.LastIndexByte(s, ':')
// a.b.c.d.1234 or [a:b:c:d].1234
i2 := strings.LastIndexByte(s, '.')
i := i1
if i2 > i {
i = i2
}
if i < 0 {
// no match; weird
return -1
}
portstr := s[i+1:]
if portstr == "*" {
return 0
}
port, err := strconv.ParseUint(portstr, 10, 16)
if err != nil {
// invalid port; weird
return -1
}
return int(port)
}
func isLoopbackAddr(s string) bool {
return strings.HasPrefix(s, "127.") ||
strings.HasPrefix(s, "[::1]:") ||
strings.HasPrefix(s, "::1.")
}
type nothing struct{}
// Lowest common denominator parser for "netstat -na" format.
// All of Linux, Windows, and macOS support -na and give similar-ish output
// formats that we can parse without special detection logic.
// Unfortunately, options to filter by proto or state are non-portable,
// so we'll filter for ourselves.
func parsePortsNetstat(output string) List {
m := map[Port]nothing{}
lines := strings.Split(string(output), "\n")
var lastline string
var lastport Port
for _, line := range lines {
trimline := strings.TrimSpace(line)
cols := strings.Fields(trimline)
if len(cols) < 1 {
continue
}
protos := strings.ToLower(cols[0])
var proto, laddr, raddr string
if strings.HasPrefix(protos, "tcp") {
if len(cols) < 4 {
continue
}
proto = "tcp"
laddr = cols[len(cols)-3]
raddr = cols[len(cols)-2]
state := cols[len(cols)-1]
if !strings.HasPrefix(state, "LISTEN") {
// not interested in non-listener sockets
continue
}
if isLoopbackAddr(laddr) {
// not interested in loopback-bound listeners
continue
}
} else if strings.HasPrefix(protos, "udp") {
if len(cols) < 3 {
continue
}
proto = "udp"
laddr = cols[len(cols)-2]
raddr = cols[len(cols)-1]
if isLoopbackAddr(laddr) {
// not interested in loopback-bound listeners
continue
}
} else if protos[0] == '[' && len(trimline) > 2 {
// Windows: with netstat -nab, appends a line like:
// [description]
// after the port line.
p := lastport
delete(m, lastport)
proc := trimline[1 : len(trimline)-1]
if proc == "svchost.exe" && lastline != "" {
p.Process = argvSubject(lastline)
} else {
p.Process = argvSubject(proc)
}
m[p] = nothing{}
} else {
// not interested in other protocols
lastline = trimline
continue
}
lport := parsePort(laddr)
rport := parsePort(raddr)
if rport != 0 || lport <= 0 {
// not interested in "connected" sockets
continue
}
p := Port{
Proto: proto,
Port: uint16(lport),
}
m[p] = nothing{}
lastport = p
lastline = ""
}
l := []Port{}
for p := range m {
l = append(l, p)
}
sort.Slice(l, func(i, j int) bool {
return (&l[i]).lessThan(&l[j])
})
return l
}
|
