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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
// Copyright 2011 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 dragonfly freebsd linux netbsd openbsd solaris
package net
import (
"errors"
"sync"
)
var onceReadProtocols sync.Once
// readProtocols loads contents of /etc/protocols into protocols map
// for quick access.
func readProtocols() {
if file, err := open("/etc/protocols"); err == nil {
for line, ok := file.readLine(); ok; line, ok = file.readLine() {
// tcp 6 TCP # transmission control protocol
if i := byteIndex(line, '#'); i >= 0 {
line = line[0:i]
}
f := getFields(line)
if len(f) < 2 {
continue
}
if proto, _, ok := dtoi(f[1], 0); ok {
if _, ok := protocols[f[0]]; !ok {
protocols[f[0]] = proto
}
for _, alias := range f[2:] {
if _, ok := protocols[alias]; !ok {
protocols[alias] = proto
}
}
}
}
file.close()
}
}
// lookupProtocol looks up IP protocol name in /etc/protocols and
// returns correspondent protocol number.
func lookupProtocol(name string) (proto int, err error) {
onceReadProtocols.Do(readProtocols)
proto, found := protocols[name]
if !found {
return 0, errors.New("unknown IP protocol specified: " + name)
}
return
}
func lookupHost(host string) (addrs []string, err error) {
addrs, err, ok := cgoLookupHost(host)
if !ok {
addrs, err = goLookupHost(host)
}
return
}
func lookupIP(host string) (addrs []IP, err error) {
addrs, err, ok := cgoLookupIP(host)
if !ok {
addrs, err = goLookupIP(host)
}
return
}
func lookupPort(network, service string) (port int, err error) {
port, err, ok := cgoLookupPort(network, service)
if !ok {
port, err = goLookupPort(network, service)
}
return
}
func lookupCNAME(name string) (cname string, err error) {
cname, err, ok := cgoLookupCNAME(name)
if !ok {
cname, err = goLookupCNAME(name)
}
return
}
func lookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
var target string
if service == "" && proto == "" {
target = name
} else {
target = "_" + service + "._" + proto + "." + name
}
var records []dnsRR
cname, records, err = lookup(target, dnsTypeSRV)
if err != nil {
return
}
addrs = make([]*SRV, len(records))
for i, rr := range records {
r := rr.(*dnsRR_SRV)
addrs[i] = &SRV{r.Target, r.Port, r.Priority, r.Weight}
}
byPriorityWeight(addrs).sort()
return
}
func lookupMX(name string) (mx []*MX, err error) {
_, records, err := lookup(name, dnsTypeMX)
if err != nil {
return
}
mx = make([]*MX, len(records))
for i, rr := range records {
r := rr.(*dnsRR_MX)
mx[i] = &MX{r.Mx, r.Pref}
}
byPref(mx).sort()
return
}
func lookupNS(name string) (ns []*NS, err error) {
_, records, err := lookup(name, dnsTypeNS)
if err != nil {
return
}
ns = make([]*NS, len(records))
for i, r := range records {
r := r.(*dnsRR_NS)
ns[i] = &NS{r.Ns}
}
return
}
func lookupTXT(name string) (txt []string, err error) {
_, records, err := lookup(name, dnsTypeTXT)
if err != nil {
return
}
txt = make([]string, len(records))
for i, r := range records {
txt[i] = r.(*dnsRR_TXT).Txt
}
return
}
func lookupAddr(addr string) (name []string, err error) {
name = lookupStaticAddr(addr)
if len(name) > 0 {
return
}
var arpa string
arpa, err = reverseaddr(addr)
if err != nil {
return
}
var records []dnsRR
_, records, err = lookup(arpa, dnsTypePTR)
if err != nil {
return
}
name = make([]string, len(records))
for i := range records {
r := records[i].(*dnsRR_PTR)
name[i] = r.Ptr
}
return
}
|
