mirror of git://gcc.gnu.org/git/gcc.git
342 lines
10 KiB
Go
342 lines
10 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"context"
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"os"
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"runtime"
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"syscall"
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"unsafe"
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)
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func getprotobyname(name string) (proto int, err error) {
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p, err := syscall.GetProtoByName(name)
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if err != nil {
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return 0, os.NewSyscallError("getprotobyname", err)
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}
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return int(p.Proto), nil
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}
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// lookupProtocol looks up IP protocol name and returns correspondent protocol number.
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func lookupProtocol(ctx context.Context, name string) (int, error) {
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// GetProtoByName return value is stored in thread local storage.
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// Start new os thread before the call to prevent races.
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type result struct {
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proto int
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err error
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}
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ch := make(chan result) // unbuffered
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go func() {
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acquireThread()
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defer releaseThread()
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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proto, err := getprotobyname(name)
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select {
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case ch <- result{proto: proto, err: err}:
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case <-ctx.Done():
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}
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}()
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select {
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case r := <-ch:
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if r.err != nil {
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if proto, ok := protocols[name]; ok {
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return proto, nil
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}
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r.err = &DNSError{Err: r.err.Error(), Name: name}
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}
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return r.proto, r.err
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case <-ctx.Done():
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return 0, mapErr(ctx.Err())
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}
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}
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func lookupHost(ctx context.Context, name string) ([]string, error) {
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ips, err := lookupIP(ctx, name)
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if err != nil {
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return nil, err
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}
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addrs := make([]string, 0, len(ips))
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for _, ip := range ips {
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addrs = append(addrs, ip.String())
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}
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return addrs, nil
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}
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func lookupIP(ctx context.Context, name string) ([]IPAddr, error) {
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// TODO(bradfitz,brainman): use ctx?
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type ret struct {
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addrs []IPAddr
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err error
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}
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ch := make(chan ret, 1)
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go func() {
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acquireThread()
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defer releaseThread()
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hints := syscall.AddrinfoW{
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Family: syscall.AF_UNSPEC,
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Socktype: syscall.SOCK_STREAM,
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Protocol: syscall.IPPROTO_IP,
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}
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var result *syscall.AddrinfoW
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e := syscall.GetAddrInfoW(syscall.StringToUTF16Ptr(name), nil, &hints, &result)
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if e != nil {
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ch <- ret{err: &DNSError{Err: os.NewSyscallError("getaddrinfow", e).Error(), Name: name}}
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}
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defer syscall.FreeAddrInfoW(result)
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addrs := make([]IPAddr, 0, 5)
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for ; result != nil; result = result.Next {
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addr := unsafe.Pointer(result.Addr)
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switch result.Family {
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case syscall.AF_INET:
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a := (*syscall.RawSockaddrInet4)(addr).Addr
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addrs = append(addrs, IPAddr{IP: IPv4(a[0], a[1], a[2], a[3])})
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case syscall.AF_INET6:
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a := (*syscall.RawSockaddrInet6)(addr).Addr
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zone := zoneToString(int((*syscall.RawSockaddrInet6)(addr).Scope_id))
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addrs = append(addrs, IPAddr{IP: 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]}, Zone: zone})
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default:
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ch <- ret{err: &DNSError{Err: syscall.EWINDOWS.Error(), Name: name}}
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}
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}
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ch <- ret{addrs: addrs}
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}()
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select {
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case r := <-ch:
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return r.addrs, r.err
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case <-ctx.Done():
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// TODO(bradfitz,brainman): cancel the ongoing
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// GetAddrInfoW? It would require conditionally using
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// GetAddrInfoEx with lpOverlapped, which requires
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// Windows 8 or newer. I guess we'll need oldLookupIP,
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// newLookupIP, and newerLookUP.
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//
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// For now we just let it finish and write to the
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// buffered channel.
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return nil, &DNSError{
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Name: name,
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Err: ctx.Err().Error(),
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IsTimeout: ctx.Err() == context.DeadlineExceeded,
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}
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}
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}
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func lookupPort(ctx context.Context, network, service string) (int, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var stype int32
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switch network {
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case "tcp4", "tcp6":
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stype = syscall.SOCK_STREAM
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case "udp4", "udp6":
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stype = syscall.SOCK_DGRAM
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}
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hints := syscall.AddrinfoW{
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Family: syscall.AF_UNSPEC,
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Socktype: stype,
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Protocol: syscall.IPPROTO_IP,
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}
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var result *syscall.AddrinfoW
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e := syscall.GetAddrInfoW(nil, syscall.StringToUTF16Ptr(service), &hints, &result)
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if e != nil {
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return 0, &DNSError{Err: os.NewSyscallError("getaddrinfow", e).Error(), Name: network + "/" + service}
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}
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defer syscall.FreeAddrInfoW(result)
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if result == nil {
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return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service}
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}
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addr := unsafe.Pointer(result.Addr)
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switch result.Family {
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case syscall.AF_INET:
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a := (*syscall.RawSockaddrInet4)(addr)
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return int(syscall.Ntohs(a.Port)), nil
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case syscall.AF_INET6:
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a := (*syscall.RawSockaddrInet6)(addr)
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return int(syscall.Ntohs(a.Port)), nil
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}
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return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service}
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}
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func lookupCNAME(ctx context.Context, name string) (string, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &r, nil)
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// windows returns DNS_INFO_NO_RECORDS if there are no CNAME-s
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if errno, ok := e.(syscall.Errno); ok && errno == syscall.DNS_INFO_NO_RECORDS {
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// if there are no aliases, the canonical name is the input name
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return absDomainName([]byte(name)), nil
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}
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if e != nil {
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return "", &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: name}
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}
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defer syscall.DnsRecordListFree(r, 1)
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resolved := resolveCNAME(syscall.StringToUTF16Ptr(name), r)
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cname := syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(resolved))[:])
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return absDomainName([]byte(cname)), nil
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}
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func lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var target string
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if service == "" && proto == "" {
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target = name
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} else {
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target = "_" + service + "._" + proto + "." + name
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}
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &r, nil)
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if e != nil {
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return "", nil, &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: target}
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}
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defer syscall.DnsRecordListFree(r, 1)
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srvs := make([]*SRV, 0, 10)
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for _, p := range validRecs(r, syscall.DNS_TYPE_SRV, target) {
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v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
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srvs = append(srvs, &SRV{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:]))), v.Port, v.Priority, v.Weight})
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}
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byPriorityWeight(srvs).sort()
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return absDomainName([]byte(target)), srvs, nil
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}
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func lookupMX(ctx context.Context, name string) ([]*MX, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &r, nil)
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if e != nil {
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return nil, &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: name}
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}
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defer syscall.DnsRecordListFree(r, 1)
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mxs := make([]*MX, 0, 10)
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for _, p := range validRecs(r, syscall.DNS_TYPE_MX, name) {
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v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
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mxs = append(mxs, &MX{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.NameExchange))[:]))), v.Preference})
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}
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byPref(mxs).sort()
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return mxs, nil
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}
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func lookupNS(ctx context.Context, name string) ([]*NS, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(name, syscall.DNS_TYPE_NS, 0, nil, &r, nil)
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if e != nil {
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return nil, &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: name}
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}
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defer syscall.DnsRecordListFree(r, 1)
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nss := make([]*NS, 0, 10)
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for _, p := range validRecs(r, syscall.DNS_TYPE_NS, name) {
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v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
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nss = append(nss, &NS{absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:])))})
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}
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return nss, nil
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}
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func lookupTXT(ctx context.Context, name string) ([]string, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(name, syscall.DNS_TYPE_TEXT, 0, nil, &r, nil)
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if e != nil {
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return nil, &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: name}
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}
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defer syscall.DnsRecordListFree(r, 1)
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txts := make([]string, 0, 10)
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for _, p := range validRecs(r, syscall.DNS_TYPE_TEXT, name) {
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d := (*syscall.DNSTXTData)(unsafe.Pointer(&p.Data[0]))
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for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount] {
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s := syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(v))[:])
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txts = append(txts, s)
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}
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}
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return txts, nil
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}
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func lookupAddr(ctx context.Context, addr string) ([]string, error) {
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// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
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acquireThread()
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defer releaseThread()
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arpa, err := reverseaddr(addr)
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if err != nil {
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return nil, err
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}
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var r *syscall.DNSRecord
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e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &r, nil)
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if e != nil {
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return nil, &DNSError{Err: os.NewSyscallError("dnsquery", e).Error(), Name: addr}
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}
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defer syscall.DnsRecordListFree(r, 1)
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ptrs := make([]string, 0, 10)
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for _, p := range validRecs(r, syscall.DNS_TYPE_PTR, arpa) {
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v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
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ptrs = append(ptrs, absDomainName([]byte(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))))
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}
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return ptrs, nil
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}
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const dnsSectionMask = 0x0003
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// returns only results applicable to name and resolves CNAME entries
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func validRecs(r *syscall.DNSRecord, dnstype uint16, name string) []*syscall.DNSRecord {
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cname := syscall.StringToUTF16Ptr(name)
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if dnstype != syscall.DNS_TYPE_CNAME {
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cname = resolveCNAME(cname, r)
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}
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rec := make([]*syscall.DNSRecord, 0, 10)
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for p := r; p != nil; p = p.Next {
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if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer {
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continue
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}
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if p.Type != dnstype {
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continue
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}
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if !syscall.DnsNameCompare(cname, p.Name) {
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continue
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}
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rec = append(rec, p)
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}
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return rec
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}
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// returns the last CNAME in chain
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func resolveCNAME(name *uint16, r *syscall.DNSRecord) *uint16 {
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// limit cname resolving to 10 in case of a infinite CNAME loop
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Cname:
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for cnameloop := 0; cnameloop < 10; cnameloop++ {
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for p := r; p != nil; p = p.Next {
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if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer {
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continue
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}
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if p.Type != syscall.DNS_TYPE_CNAME {
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continue
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}
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if !syscall.DnsNameCompare(name, p.Name) {
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continue
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}
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name = (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0])).Host
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continue Cname
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}
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break
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}
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return name
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}
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