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
169
170
171
172
173
174
175
176
|
// 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.
package net
import (
"os"
"sync"
"syscall"
"unsafe"
)
var (
protoentLock sync.Mutex
hostentLock sync.Mutex
serventLock sync.Mutex
)
// lookupProtocol looks up IP protocol name and returns correspondent protocol number.
func lookupProtocol(name string) (proto int, err error) {
protoentLock.Lock()
defer protoentLock.Unlock()
p, e := syscall.GetProtoByName(name)
if e != nil {
return 0, os.NewSyscallError("GetProtoByName", e)
}
return int(p.Proto), nil
}
func LookupHost(name string) (addrs []string, err error) {
ips, err := LookupIP(name)
if err != nil {
return
}
addrs = make([]string, 0, len(ips))
for _, ip := range ips {
addrs = append(addrs, ip.String())
}
return
}
func LookupIP(name string) (addrs []IP, err error) {
hostentLock.Lock()
defer hostentLock.Unlock()
h, e := syscall.GetHostByName(name)
if e != nil {
return nil, os.NewSyscallError("GetHostByName", e)
}
switch h.AddrType {
case syscall.AF_INET:
i := 0
addrs = make([]IP, 100) // plenty of room to grow
for p := (*[100](*[4]byte))(unsafe.Pointer(h.AddrList)); i < cap(addrs) && p[i] != nil; i++ {
addrs[i] = IPv4(p[i][0], p[i][1], p[i][2], p[i][3])
}
addrs = addrs[0:i]
default: // TODO(vcc): Implement non IPv4 address lookups.
return nil, os.NewSyscallError("LookupHost", syscall.EWINDOWS)
}
return addrs, nil
}
func LookupPort(network, service string) (port int, err error) {
switch network {
case "tcp4", "tcp6":
network = "tcp"
case "udp4", "udp6":
network = "udp"
}
serventLock.Lock()
defer serventLock.Unlock()
s, e := syscall.GetServByName(service, network)
if e != nil {
return 0, os.NewSyscallError("GetServByName", e)
}
return int(syscall.Ntohs(s.Port)), nil
}
func LookupCNAME(name string) (cname string, err error) {
var r *syscall.DNSRecord
e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &r, nil)
if e != 0 {
return "", os.NewSyscallError("LookupCNAME", e)
}
defer syscall.DnsRecordListFree(r, 1)
if r != nil && r.Type == syscall.DNS_TYPE_CNAME {
v := (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0]))
cname = syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."
}
return
}
// LookupSRV tries to resolve an SRV query of the given service,
// protocol, and domain name. The proto is "tcp" or "udp".
// The returned records are sorted by priority and randomized
// by weight within a priority.
//
// LookupSRV constructs the DNS name to look up following RFC 2782.
// That is, it looks up _service._proto.name. To accommodate services
// publishing SRV records under non-standard names, if both service
// and proto are empty strings, LookupSRV looks up name directly.
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 r *syscall.DNSRecord
e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &r, nil)
if e != 0 {
return "", nil, os.NewSyscallError("LookupSRV", e)
}
defer syscall.DnsRecordListFree(r, 1)
addrs = make([]*SRV, 0, 10)
for p := r; p != nil && p.Type == syscall.DNS_TYPE_SRV; p = p.Next {
v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
addrs = append(addrs, &SRV{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight})
}
byPriorityWeight(addrs).sort()
return name, addrs, nil
}
func LookupMX(name string) (mx []*MX, err error) {
var r *syscall.DNSRecord
e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &r, nil)
if e != 0 {
return nil, os.NewSyscallError("LookupMX", e)
}
defer syscall.DnsRecordListFree(r, 1)
mx = make([]*MX, 0, 10)
for p := r; p != nil && p.Type == syscall.DNS_TYPE_MX; p = p.Next {
v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
mx = append(mx, &MX{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]) + ".", v.Preference})
}
byPref(mx).sort()
return mx, nil
}
func LookupTXT(name string) (txt []string, err error) {
var r *syscall.DNSRecord
e := syscall.DnsQuery(name, syscall.DNS_TYPE_TEXT, 0, nil, &r, nil)
if e != 0 {
return nil, os.NewSyscallError("LookupTXT", e)
}
defer syscall.DnsRecordListFree(r, 1)
txt = make([]string, 0, 10)
if r != nil && r.Type == syscall.DNS_TYPE_TEXT {
d := (*syscall.DNSTXTData)(unsafe.Pointer(&r.Data[0]))
for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount] {
s := syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(v))[:])
txt = append(txt, s)
}
}
return
}
func LookupAddr(addr string) (name []string, err error) {
arpa, err := reverseaddr(addr)
if err != nil {
return nil, err
}
var r *syscall.DNSRecord
e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &r, nil)
if e != 0 {
return nil, os.NewSyscallError("LookupAddr", e)
}
defer syscall.DnsRecordListFree(r, 1)
name = make([]string, 0, 10)
for p := r; p != nil && p.Type == syscall.DNS_TYPE_PTR; p = p.Next {
v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
name = append(name, syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))
}
return name, nil
}
|
