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
|
// Copyright 2009 The Go 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 darwin freebsd linux netbsd openbsd
// Read system port mappings from /etc/services
package net
import "sync"
var services map[string]map[string]int
var servicesError error
var onceReadServices sync.Once
func readServices() {
services = make(map[string]map[string]int)
var file *file
if file, servicesError = open("/etc/services"); servicesError != nil {
return
}
for line, ok := file.readLine(); ok; line, ok = file.readLine() {
// "http 80/tcp www www-http # World Wide Web HTTP"
if i := byteIndex(line, '#'); i >= 0 {
line = line[0:i]
}
f := getFields(line)
if len(f) < 2 {
continue
}
portnet := f[1] // "tcp/80"
port, j, ok := dtoi(portnet, 0)
if !ok || port <= 0 || j >= len(portnet) || portnet[j] != '/' {
continue
}
netw := portnet[j+1:] // "tcp"
m, ok1 := services[netw]
if !ok1 {
m = make(map[string]int)
services[netw] = m
}
for i := 0; i < len(f); i++ {
if i != 1 { // f[1] was port/net
m[f[i]] = port
}
}
}
file.close()
}
// goLookupPort is the native Go implementation of LookupPort.
func goLookupPort(network, service string) (port int, err error) {
onceReadServices.Do(readServices)
switch network {
case "tcp4", "tcp6":
network = "tcp"
case "udp4", "udp6":
network = "udp"
}
if m, ok := services[network]; ok {
if port, ok = m[service]; ok {
return
}
}
return 0, &AddrError{"unknown port", network + "/" + service}
}
|
