1 // Copyright 2009 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
15 protoentLock sync.Mutex
16 hostentLock sync.Mutex
17 serventLock sync.Mutex
20 // lookupProtocol looks up IP protocol name and returns correspondent protocol number.
21 func lookupProtocol(name string) (proto int, err error) {
23 defer protoentLock.Unlock()
24 p, err := syscall.GetProtoByName(name)
26 return 0, os.NewSyscallError("GetProtoByName", err)
28 return int(p.Proto), nil
31 func lookupHost(name string) (addrs []string, err error) {
32 ips, err := LookupIP(name)
36 addrs = make([]string, 0, len(ips))
37 for _, ip := range ips {
38 addrs = append(addrs, ip.String())
43 func lookupIP(name string) (addrs []IP, err error) {
45 defer hostentLock.Unlock()
46 h, err := syscall.GetHostByName(name)
48 return nil, os.NewSyscallError("GetHostByName", err)
53 addrs = make([]IP, 100) // plenty of room to grow
54 for p := (*[100](*[4]byte))(unsafe.Pointer(h.AddrList)); i < cap(addrs) && p[i] != nil; i++ {
55 addrs[i] = IPv4(p[i][0], p[i][1], p[i][2], p[i][3])
58 default: // TODO(vcc): Implement non IPv4 address lookups.
59 return nil, os.NewSyscallError("LookupHost", syscall.EWINDOWS)
64 func lookupPort(network, service string) (port int, err error) {
72 defer serventLock.Unlock()
73 s, err := syscall.GetServByName(service, network)
75 return 0, os.NewSyscallError("GetServByName", err)
77 return int(syscall.Ntohs(s.Port)), nil
80 func lookupCNAME(name string) (cname string, err error) {
81 var r *syscall.DNSRecord
82 e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &r, nil)
84 return "", os.NewSyscallError("LookupCNAME", e)
86 defer syscall.DnsRecordListFree(r, 1)
87 if r != nil && r.Type == syscall.DNS_TYPE_CNAME {
88 v := (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0]))
89 cname = syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."
94 func lookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) {
96 if service == "" && proto == "" {
99 target = "_" + service + "._" + proto + "." + name
101 var r *syscall.DNSRecord
102 e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &r, nil)
104 return "", nil, os.NewSyscallError("LookupSRV", e)
106 defer syscall.DnsRecordListFree(r, 1)
107 addrs = make([]*SRV, 0, 10)
108 for p := r; p != nil && p.Type == syscall.DNS_TYPE_SRV; p = p.Next {
109 v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
110 addrs = append(addrs, &SRV{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]), v.Port, v.Priority, v.Weight})
112 byPriorityWeight(addrs).sort()
113 return name, addrs, nil
116 func lookupMX(name string) (mx []*MX, err error) {
117 var r *syscall.DNSRecord
118 e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &r, nil)
120 return nil, os.NewSyscallError("LookupMX", e)
122 defer syscall.DnsRecordListFree(r, 1)
123 mx = make([]*MX, 0, 10)
124 for p := r; p != nil && p.Type == syscall.DNS_TYPE_MX; p = p.Next {
125 v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
126 mx = append(mx, &MX{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]) + ".", v.Preference})
132 func lookupTXT(name string) (txt []string, err error) {
133 var r *syscall.DNSRecord
134 e := syscall.DnsQuery(name, syscall.DNS_TYPE_TEXT, 0, nil, &r, nil)
136 return nil, os.NewSyscallError("LookupTXT", e)
138 defer syscall.DnsRecordListFree(r, 1)
139 txt = make([]string, 0, 10)
140 if r != nil && r.Type == syscall.DNS_TYPE_TEXT {
141 d := (*syscall.DNSTXTData)(unsafe.Pointer(&r.Data[0]))
142 for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount] {
143 s := syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(v))[:])
150 func lookupAddr(addr string) (name []string, err error) {
151 arpa, err := reverseaddr(addr)
155 var r *syscall.DNSRecord
156 e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &r, nil)
158 return nil, os.NewSyscallError("LookupAddr", e)
160 defer syscall.DnsRecordListFree(r, 1)
161 name = make([]string, 0, 10)
162 for p := r; p != nil && p.Type == syscall.DNS_TYPE_PTR; p = p.Next {
163 v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
164 name = append(name, syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))