1 files changed, 435 insertions, 0 deletions
diff --git a/src/net/lookup_windows.go b/src/net/lookup_windows.go
new file mode 100644
index 0000000..9ff39c7
--- /dev/null
+++ b/src/net/lookup_windows.go
@@ -0,0 +1,435 @@
+// 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 (
+	"context"
+	"internal/syscall/windows"
+	"os"
+	"runtime"
+	"syscall"
+	"unsafe"
+)
+
+const _WSAHOST_NOT_FOUND = syscall.Errno(11001)
+
+func winError(call string, err error) error {
+	switch err {
+	case _WSAHOST_NOT_FOUND:
+		return errNoSuchHost
+	}
+	return os.NewSyscallError(call, err)
+}
+
+func getprotobyname(name string) (proto int, err error) {
+	p, err := syscall.GetProtoByName(name)
+	if err != nil {
+		return 0, winError("getprotobyname", err)
+	}
+	return int(p.Proto), nil
+}
+
+// lookupProtocol looks up IP protocol name and returns correspondent protocol number.
+func lookupProtocol(ctx context.Context, name string) (int, error) {
+	// GetProtoByName return value is stored in thread local storage.
+	// Start new os thread before the call to prevent races.
+	type result struct {
+		proto int
+		err   error
+	}
+	ch := make(chan result) // unbuffered
+	go func() {
+		acquireThread()
+		defer releaseThread()
+		runtime.LockOSThread()
+		defer runtime.UnlockOSThread()
+		proto, err := getprotobyname(name)
+		select {
+		case ch <- result{proto: proto, err: err}:
+		case <-ctx.Done():
+		}
+	}()
+	select {
+	case r := <-ch:
+		if r.err != nil {
+			if proto, err := lookupProtocolMap(name); err == nil {
+				return proto, nil
+			}
+
+			dnsError := &DNSError{Err: r.err.Error(), Name: name}
+			if r.err == errNoSuchHost {
+				dnsError.IsNotFound = true
+			}
+			r.err = dnsError
+		}
+		return r.proto, r.err
+	case <-ctx.Done():
+		return 0, mapErr(ctx.Err())
+	}
+}
+
+func (r *Resolver) lookupHost(ctx context.Context, name string) ([]string, error) {
+	ips, err := r.lookupIP(ctx, "ip", name)
+	if err != nil {
+		return nil, err
+	}
+	addrs := make([]string, 0, len(ips))
+	for _, ip := range ips {
+		addrs = append(addrs, ip.String())
+	}
+	return addrs, nil
+}
+
+// preferGoOverWindows reports whether the resolver should use the
+// pure Go implementation rather than making win32 calls to ask the
+// kernel for its answer.
+func (r *Resolver) preferGoOverWindows() bool {
+	conf := systemConf()
+	order := conf.hostLookupOrder(r, "") // name is unused
+	return order != hostLookupCgo
+}
+
+func (r *Resolver) lookupIP(ctx context.Context, network, name string) ([]IPAddr, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupIP(ctx, network, name)
+	}
+	// TODO(bradfitz,brainman): use ctx more. See TODO below.
+
+	var family int32 = syscall.AF_UNSPEC
+	switch ipVersion(network) {
+	case '4':
+		family = syscall.AF_INET
+	case '6':
+		family = syscall.AF_INET6
+	}
+
+	getaddr := func() ([]IPAddr, error) {
+		acquireThread()
+		defer releaseThread()
+		hints := syscall.AddrinfoW{
+			Family:   family,
+			Socktype: syscall.SOCK_STREAM,
+			Protocol: syscall.IPPROTO_IP,
+		}
+		var result *syscall.AddrinfoW
+		name16p, err := syscall.UTF16PtrFromString(name)
+		if err != nil {
+			return nil, &DNSError{Name: name, Err: err.Error()}
+		}
+		e := syscall.GetAddrInfoW(name16p, nil, &hints, &result)
+		if e != nil {
+			err := winError("getaddrinfow", e)
+			dnsError := &DNSError{Err: err.Error(), Name: name}
+			if err == errNoSuchHost {
+				dnsError.IsNotFound = true
+			}
+			return nil, dnsError
+		}
+		defer syscall.FreeAddrInfoW(result)
+		addrs := make([]IPAddr, 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, IPAddr{IP: IPv4(a[0], a[1], a[2], a[3])})
+			case syscall.AF_INET6:
+				a := (*syscall.RawSockaddrInet6)(addr).Addr
+				zone := zoneCache.name(int((*syscall.RawSockaddrInet6)(addr).Scope_id))
+				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})
+			default:
+				return nil, &DNSError{Err: syscall.EWINDOWS.Error(), Name: name}
+			}
+		}
+		return addrs, nil
+	}
+
+	type ret struct {
+		addrs []IPAddr
+		err   error
+	}
+
+	var ch chan ret
+	if ctx.Err() == nil {
+		ch = make(chan ret, 1)
+		go func() {
+			addr, err := getaddr()
+			ch <- ret{addrs: addr, err: err}
+		}()
+	}
+
+	select {
+	case r := <-ch:
+		return r.addrs, r.err
+	case <-ctx.Done():
+		// TODO(bradfitz,brainman): cancel the ongoing
+		// GetAddrInfoW? It would require conditionally using
+		// GetAddrInfoEx with lpOverlapped, which requires
+		// Windows 8 or newer. I guess we'll need oldLookupIP,
+		// newLookupIP, and newerLookUP.
+		//
+		// For now we just let it finish and write to the
+		// buffered channel.
+		return nil, &DNSError{
+			Name:      name,
+			Err:       ctx.Err().Error(),
+			IsTimeout: ctx.Err() == context.DeadlineExceeded,
+		}
+	}
+}
+
+func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int, error) {
+	if r.preferGoOverWindows() {
+		return lookupPortMap(network, service)
+	}
+
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var stype int32
+	switch network {
+	case "tcp4", "tcp6":
+		stype = syscall.SOCK_STREAM
+	case "udp4", "udp6":
+		stype = syscall.SOCK_DGRAM
+	}
+	hints := syscall.AddrinfoW{
+		Family:   syscall.AF_UNSPEC,
+		Socktype: stype,
+		Protocol: syscall.IPPROTO_IP,
+	}
+	var result *syscall.AddrinfoW
+	e := syscall.GetAddrInfoW(nil, syscall.StringToUTF16Ptr(service), &hints, &result)
+	if e != nil {
+		if port, err := lookupPortMap(network, service); err == nil {
+			return port, nil
+		}
+		err := winError("getaddrinfow", e)
+		dnsError := &DNSError{Err: err.Error(), Name: network + "/" + service}
+		if err == errNoSuchHost {
+			dnsError.IsNotFound = true
+		}
+		return 0, dnsError
+	}
+	defer syscall.FreeAddrInfoW(result)
+	if result == nil {
+		return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service}
+	}
+	addr := unsafe.Pointer(result.Addr)
+	switch result.Family {
+	case syscall.AF_INET:
+		a := (*syscall.RawSockaddrInet4)(addr)
+		return int(syscall.Ntohs(a.Port)), nil
+	case syscall.AF_INET6:
+		a := (*syscall.RawSockaddrInet6)(addr)
+		return int(syscall.Ntohs(a.Port)), nil
+	}
+	return 0, &DNSError{Err: syscall.EINVAL.Error(), Name: network + "/" + service}
+}
+
+func (r *Resolver) lookupCNAME(ctx context.Context, name string) (string, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupCNAME(ctx, name)
+	}
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(name, syscall.DNS_TYPE_CNAME, 0, nil, &rec, nil)
+	// windows returns DNS_INFO_NO_RECORDS if there are no CNAME-s
+	if errno, ok := e.(syscall.Errno); ok && errno == syscall.DNS_INFO_NO_RECORDS {
+		// if there are no aliases, the canonical name is the input name
+		return absDomainName(name), nil
+	}
+	if e != nil {
+		return "", &DNSError{Err: winError("dnsquery", e).Error(), Name: name}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	resolved := resolveCNAME(syscall.StringToUTF16Ptr(name), rec)
+	cname := windows.UTF16PtrToString(resolved)
+	return absDomainName(cname), nil
+}
+
+func (r *Resolver) lookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupSRV(ctx, service, proto, name)
+	}
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var target string
+	if service == "" && proto == "" {
+		target = name
+	} else {
+		target = "_" + service + "._" + proto + "." + name
+	}
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(target, syscall.DNS_TYPE_SRV, 0, nil, &rec, nil)
+	if e != nil {
+		return "", nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: target}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	srvs := make([]*SRV, 0, 10)
+	for _, p := range validRecs(rec, syscall.DNS_TYPE_SRV, target) {
+		v := (*syscall.DNSSRVData)(unsafe.Pointer(&p.Data[0]))
+		srvs = append(srvs, &SRV{absDomainName(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Target))[:])), v.Port, v.Priority, v.Weight})
+	}
+	byPriorityWeight(srvs).sort()
+	return absDomainName(target), srvs, nil
+}
+
+func (r *Resolver) lookupMX(ctx context.Context, name string) ([]*MX, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupMX(ctx, name)
+	}
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(name, syscall.DNS_TYPE_MX, 0, nil, &rec, nil)
+	if e != nil {
+		return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	mxs := make([]*MX, 0, 10)
+	for _, p := range validRecs(rec, syscall.DNS_TYPE_MX, name) {
+		v := (*syscall.DNSMXData)(unsafe.Pointer(&p.Data[0]))
+		mxs = append(mxs, &MX{absDomainName(windows.UTF16PtrToString(v.NameExchange)), v.Preference})
+	}
+	byPref(mxs).sort()
+	return mxs, nil
+}
+
+func (r *Resolver) lookupNS(ctx context.Context, name string) ([]*NS, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupNS(ctx, name)
+	}
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(name, syscall.DNS_TYPE_NS, 0, nil, &rec, nil)
+	if e != nil {
+		return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	nss := make([]*NS, 0, 10)
+	for _, p := range validRecs(rec, syscall.DNS_TYPE_NS, name) {
+		v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
+		nss = append(nss, &NS{absDomainName(syscall.UTF16ToString((*[256]uint16)(unsafe.Pointer(v.Host))[:]))})
+	}
+	return nss, nil
+}
+
+func (r *Resolver) lookupTXT(ctx context.Context, name string) ([]string, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupTXT(ctx, name)
+	}
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(name, syscall.DNS_TYPE_TEXT, 0, nil, &rec, nil)
+	if e != nil {
+		return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: name}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	txts := make([]string, 0, 10)
+	for _, p := range validRecs(rec, syscall.DNS_TYPE_TEXT, name) {
+		d := (*syscall.DNSTXTData)(unsafe.Pointer(&p.Data[0]))
+		s := ""
+		for _, v := range (*[1 << 10]*uint16)(unsafe.Pointer(&(d.StringArray[0])))[:d.StringCount:d.StringCount] {
+			s += windows.UTF16PtrToString(v)
+		}
+		txts = append(txts, s)
+	}
+	return txts, nil
+}
+
+func (r *Resolver) lookupAddr(ctx context.Context, addr string) ([]string, error) {
+	if r.preferGoOverWindows() {
+		return r.goLookupPTR(ctx, addr)
+	}
+
+	// TODO(bradfitz): finish ctx plumbing. Nothing currently depends on this.
+	acquireThread()
+	defer releaseThread()
+	arpa, err := reverseaddr(addr)
+	if err != nil {
+		return nil, err
+	}
+	var rec *syscall.DNSRecord
+	e := syscall.DnsQuery(arpa, syscall.DNS_TYPE_PTR, 0, nil, &rec, nil)
+	if e != nil {
+		return nil, &DNSError{Err: winError("dnsquery", e).Error(), Name: addr}
+	}
+	defer syscall.DnsRecordListFree(rec, 1)
+
+	ptrs := make([]string, 0, 10)
+	for _, p := range validRecs(rec, syscall.DNS_TYPE_PTR, arpa) {
+		v := (*syscall.DNSPTRData)(unsafe.Pointer(&p.Data[0]))
+		ptrs = append(ptrs, absDomainName(windows.UTF16PtrToString(v.Host)))
+	}
+	return ptrs, nil
+}
+
+const dnsSectionMask = 0x0003
+
+// returns only results applicable to name and resolves CNAME entries
+func validRecs(r *syscall.DNSRecord, dnstype uint16, name string) []*syscall.DNSRecord {
+	cname := syscall.StringToUTF16Ptr(name)
+	if dnstype != syscall.DNS_TYPE_CNAME {
+		cname = resolveCNAME(cname, r)
+	}
+	rec := make([]*syscall.DNSRecord, 0, 10)
+	for p := r; p != nil; p = p.Next {
+		// in case of a local machine, DNS records are returned with DNSREC_QUESTION flag instead of DNS_ANSWER
+		if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer && p.Dw&dnsSectionMask != syscall.DnsSectionQuestion {
+			continue
+		}
+		if p.Type != dnstype {
+			continue
+		}
+		if !syscall.DnsNameCompare(cname, p.Name) {
+			continue
+		}
+		rec = append(rec, p)
+	}
+	return rec
+}
+
+// returns the last CNAME in chain
+func resolveCNAME(name *uint16, r *syscall.DNSRecord) *uint16 {
+	// limit cname resolving to 10 in case of an infinite CNAME loop
+Cname:
+	for cnameloop := 0; cnameloop < 10; cnameloop++ {
+		for p := r; p != nil; p = p.Next {
+			if p.Dw&dnsSectionMask != syscall.DnsSectionAnswer {
+				continue
+			}
+			if p.Type != syscall.DNS_TYPE_CNAME {
+				continue
+			}
+			if !syscall.DnsNameCompare(name, p.Name) {
+				continue
+			}
+			name = (*syscall.DNSPTRData)(unsafe.Pointer(&r.Data[0])).Host
+			continue Cname
+		}
+		break
+	}
+	return name
+}
+
+// concurrentThreadsLimit returns the number of threads we permit to
+// run concurrently doing DNS lookups.
+func concurrentThreadsLimit() int {
+	return 500
+}