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// 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, err := syscall.GetProtoByName(name)
if err != nil {
return 0, os.NewSyscallError("GetProtoByName", err)
}
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
}
var lookupIP = oldLookupIP
func oldLookupIP(name string) (addrs []IP, err error) {
hostentLock.Lock()
defer hostentLock.Unlock()
h, err := syscall.GetHostByName(name)
if err != nil {
return nil, os.NewSyscallError("GetHostByName", err)
}
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("LookupIP", syscall.EWINDOWS)
}
return addrs, nil
}
func newLookupIP(name string) (addrs []IP, err error) {
hints := syscall.AddrinfoW{
Family: syscall.AF_UNSPEC,
Socktype: syscall.SOCK_STREAM,
Protocol: syscall.IPPROTO_IP,
}
var result *syscall.AddrinfoW
e := syscall.GetAddrInfoW(syscall.StringToUTF16Ptr(name), nil, &hints, &result)
if e != nil {
return nil, os.NewSyscallError("GetAddrInfoW", e)
}
defer syscall.FreeAddrInfoW(result)
addrs = make([]IP, 0, 5)
for ; result != nil; result = result.Next {
addr := unsafe.Pointer(result.Addr)
switch result.Family {
case syscall.AF_INET:
a := (*syscall.RawSockaddrInet4)(addr).Addr
addrs = append(addrs, IPv4(a[0], a[1], a[2], a[3]))
case syscall.AF_INET6:
a := (*syscall.RawSockaddrInet6)(addr).Addr
addrs = append(addrs, IP{a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15]})
default:
return nil, os.NewSyscallError("LookupIP", 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, err := syscall.GetServByName(service, network)
if err != nil {
return 0, os.NewSyscallError("GetServByName", err)
}
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 != nil {
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
}
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 != nil {
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 != nil {
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 lookupNS(name string) (ns []*NS, err error) {
var r *syscall.DNSRecord
e := syscall.DnsQuery(name, syscall.DNS_TYPE_NS, 0, nil, &r, nil)
if e != nil {
return nil, os.NewSyscallError("LookupNS", e)
}
defer syscall.DnsRecordListFree(r, 1)
ns = make([]*NS, 0, 10)
for p := r; p != nil && p.Type == syscall.DNS_TYPE_NS; p = p.Next {
v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
ns = append(ns, &NS{syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]) + "."})
}
return ns, 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 != nil {
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 != nil {
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
}
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