net: implement IPv6 support for windows

Thank you zhoumichaely for original CL 5175042.

Fixes #1740.
Fixes #2315.

R=golang-dev, bradfitz, mikioh.mikioh
CC=golang-dev, zhoumichaely
https://golang.org/cl/6822045

src/pkg/net/dialgoogle_test.go

@@ -116,7 +116,12 @@ func TestDialGoogleIPv6(t *testing.T) {
 		return
 	}
 	// Only run tcp6 if the kernel will take it.
-	if !*testIPv6 || !supportsIPv6 {
+	if !supportsIPv6 {
+		t.Logf("skipping test; ipv6 is not supported")
+		return
+	}
+	if !*testIPv6 {
+		t.Logf("test disabled; use -ipv6 to enable")
 		return
 	}
 

src/pkg/net/fd_unix.go

@@ -262,6 +262,9 @@ var startServersOnce []func()
 
 var canCancelIO = true // used for testing current package
 
+func sysInit() {
+}
+
 func init() {
 	pollMaxN = runtime.NumCPU()
 	if pollMaxN > 8 {

src/pkg/net/fd_windows.go

@@ -29,13 +29,16 @@ var initErr error
 
 var canCancelIO bool // determines if CancelIoEx API is present
 
-func init() {
+func sysInit() {
 	var d syscall.WSAData
 	e := syscall.WSAStartup(uint32(0x202), &d)
 	if e != nil {
 		initErr = os.NewSyscallError("WSAStartup", e)
 	}
 	canCancelIO = syscall.LoadCancelIoEx() == nil
+	if syscall.LoadGetAddrInfo() == nil {
+		lookupIP = newLookupIP
+	}
 }
 
 func closesocket(s syscall.Handle) error {

src/pkg/net/ipsock.go

@@ -6,7 +6,12 @@
 
 package net
 
-var supportsIPv6, supportsIPv4map = probeIPv6Stack()
+var supportsIPv6, supportsIPv4map bool
+
+func init() {
+	sysInit()
+	supportsIPv6, supportsIPv4map = probeIPv6Stack()
+}
 
 func firstFavoriteAddr(filter func(IP) IP, addrs []string) (addr IP) {
 	if filter == nil {

src/pkg/net/ipsock_plan9.go

@@ -26,6 +26,9 @@ func probeIPv6Stack() (supportsIPv6, supportsIPv4map bool) {
 
 var canCancelIO = true // used for testing current package
 
+func sysInit() {
+}
+
 // parsePlan9Addr parses address of the form [ip!]port (e.g. 127.0.0.1!80).
 func parsePlan9Addr(s string) (ip IP, iport int, err error) {
 	addr := IPv4zero // address contains port only

src/pkg/net/lookup_windows.go

@@ -40,7 +40,9 @@ func lookupHost(name string) (addrs []string, err error) {
 	return
 }
 
-func lookupIP(name string) (addrs []IP, err error) {
+var lookupIP = oldLookupIP
+
+func oldLookupIP(name string) (addrs []IP, err error) {
 	hostentLock.Lock()
 	defer hostentLock.Unlock()
 	h, err := syscall.GetHostByName(name)
@@ -56,7 +58,36 @@ func lookupIP(name string) (addrs []IP, err error) {
 		}
 		addrs = addrs[0:i]
 	default: // TODO(vcc): Implement non IPv4 address lookups.
-		return nil, os.NewSyscallError("LookupHost", syscall.EWINDOWS)
+		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
 }

src/pkg/syscall/syscall_windows.go

@@ -508,6 +508,8 @@ const socket_error = uintptr(^uint32(0))
 //sys	GetProtoByName(name string) (p *Protoent, err error) [failretval==nil] = ws2_32.getprotobyname
 //sys	DnsQuery(name string, qtype uint16, options uint32, extra *byte, qrs **DNSRecord, pr *byte) (status error) = dnsapi.DnsQuery_W
 //sys	DnsRecordListFree(rl *DNSRecord, freetype uint32) = dnsapi.DnsRecordListFree
+//sys	GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) = ws2_32.GetAddrInfoW
+//sys	FreeAddrInfoW(addrinfo *AddrinfoW) = ws2_32.FreeAddrInfoW
 //sys	GetIfEntry(pIfRow *MibIfRow) (errcode error) = iphlpapi.GetIfEntry
 //sys	GetAdaptersInfo(ai *IpAdapterInfo, ol *uint32) (errcode error) = iphlpapi.GetAdaptersInfo
 
@@ -522,6 +524,14 @@ type RawSockaddrInet4 struct {
 	Zero   [8]uint8
 }
 
+type RawSockaddrInet6 struct {
+	Family   uint16
+	Port     uint16
+	Flowinfo uint32
+	Addr     [16]byte /* in6_addr */
+	Scope_id uint32
+}
+
 type RawSockaddr struct {
 	Family uint16
 	Data   [14]int8
@@ -560,11 +570,22 @@ type SockaddrInet6 struct {
 	Port   int
 	ZoneId uint32
 	Addr   [16]byte
+	raw    RawSockaddrInet6
 }
 
 func (sa *SockaddrInet6) sockaddr() (uintptr, int32, error) {
-	// TODO(brainman): implement SockaddrInet6.sockaddr()
-	return 0, 0, EWINDOWS
+	if sa.Port < 0 || sa.Port > 0xFFFF {
+		return 0, 0, EINVAL
+	}
+	sa.raw.Family = AF_INET6
+	p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
+	p[0] = byte(sa.Port >> 8)
+	p[1] = byte(sa.Port)
+	sa.raw.Scope_id = sa.ZoneId
+	for i := 0; i < len(sa.Addr); i++ {
+		sa.raw.Addr[i] = sa.Addr[i]
+	}
+	return uintptr(unsafe.Pointer(&sa.raw)), int32(unsafe.Sizeof(sa.raw)), nil
 }
 
 type SockaddrUnix struct {
@@ -592,7 +613,15 @@ func (rsa *RawSockaddrAny) Sockaddr() (Sockaddr, error) {
 		return sa, nil
 
 	case AF_INET6:
-		return nil, EWINDOWS
+		pp := (*RawSockaddrInet6)(unsafe.Pointer(rsa))
+		sa := new(SockaddrInet6)
+		p := (*[2]byte)(unsafe.Pointer(&pp.Port))
+		sa.Port = int(p[0])<<8 + int(p[1])
+		sa.ZoneId = pp.Scope_id
+		for i := 0; i < len(sa.Addr); i++ {
+			sa.Addr[i] = pp.Addr[i]
+		}
+		return sa, nil
 	}
 	return nil, EAFNOSUPPORT
 }
@@ -659,6 +688,10 @@ func WSASendto(s Handle, bufs *WSABuf, bufcnt uint32, sent *uint32, flags uint32
 	return WSASendTo(s, bufs, bufcnt, sent, flags, (*RawSockaddrAny)(unsafe.Pointer(rsa)), l, overlapped, croutine)
 }
 
+func LoadGetAddrInfo() error {
+	return procGetAddrInfoW.Find()
+}
+
 // Invented structures to support what package os expects.
 type Rusage struct {
 	CreationTime Filetime

src/pkg/syscall/zsyscall_windows_386.go

@@ -132,6 +132,8 @@ var (
 	procgetprotobyname                   = modws2_32.NewProc("getprotobyname")
 	procDnsQuery_W                       = moddnsapi.NewProc("DnsQuery_W")
 	procDnsRecordListFree                = moddnsapi.NewProc("DnsRecordListFree")
+	procGetAddrInfoW                     = modws2_32.NewProc("GetAddrInfoW")
+	procFreeAddrInfoW                    = modws2_32.NewProc("FreeAddrInfoW")
 	procGetIfEntry                       = modiphlpapi.NewProc("GetIfEntry")
 	procGetAdaptersInfo                  = modiphlpapi.NewProc("GetAdaptersInfo")
 	procTranslateNameW                   = modsecur32.NewProc("TranslateNameW")
@@ -1537,6 +1539,19 @@ func DnsRecordListFree(rl *DNSRecord, freetype uint32) {
 	return
 }
 
+func GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) {
+	r0, _, _ := Syscall6(procGetAddrInfoW.Addr(), 4, uintptr(unsafe.Pointer(nodename)), uintptr(unsafe.Pointer(servicename)), uintptr(unsafe.Pointer(hints)), uintptr(unsafe.Pointer(result)), 0, 0)
+	if r0 != 0 {
+		sockerr = Errno(r0)
+	}
+	return
+}
+
+func FreeAddrInfoW(addrinfo *AddrinfoW) {
+	Syscall(procFreeAddrInfoW.Addr(), 1, uintptr(unsafe.Pointer(addrinfo)), 0, 0)
+	return
+}
+
 func GetIfEntry(pIfRow *MibIfRow) (errcode error) {
 	r0, _, _ := Syscall(procGetIfEntry.Addr(), 1, uintptr(unsafe.Pointer(pIfRow)), 0, 0)
 	if r0 != 0 {

src/pkg/syscall/zsyscall_windows_amd64.go

@@ -132,6 +132,8 @@ var (
 	procgetprotobyname                   = modws2_32.NewProc("getprotobyname")
 	procDnsQuery_W                       = moddnsapi.NewProc("DnsQuery_W")
 	procDnsRecordListFree                = moddnsapi.NewProc("DnsRecordListFree")
+	procGetAddrInfoW                     = modws2_32.NewProc("GetAddrInfoW")
+	procFreeAddrInfoW                    = modws2_32.NewProc("FreeAddrInfoW")
 	procGetIfEntry                       = modiphlpapi.NewProc("GetIfEntry")
 	procGetAdaptersInfo                  = modiphlpapi.NewProc("GetAdaptersInfo")
 	procTranslateNameW                   = modsecur32.NewProc("TranslateNameW")
@@ -1537,6 +1539,19 @@ func DnsRecordListFree(rl *DNSRecord, freetype uint32) {
 	return
 }
 
+func GetAddrInfoW(nodename *uint16, servicename *uint16, hints *AddrinfoW, result **AddrinfoW) (sockerr error) {
+	r0, _, _ := Syscall6(procGetAddrInfoW.Addr(), 4, uintptr(unsafe.Pointer(nodename)), uintptr(unsafe.Pointer(servicename)), uintptr(unsafe.Pointer(hints)), uintptr(unsafe.Pointer(result)), 0, 0)
+	if r0 != 0 {
+		sockerr = Errno(r0)
+	}
+	return
+}
+
+func FreeAddrInfoW(addrinfo *AddrinfoW) {
+	Syscall(procFreeAddrInfoW.Addr(), 1, uintptr(unsafe.Pointer(addrinfo)), 0, 0)
+	return
+}
+
 func GetIfEntry(pIfRow *MibIfRow) (errcode error) {
 	r0, _, _ := Syscall(procGetIfEntry.Addr(), 1, uintptr(unsafe.Pointer(pIfRow)), 0, 0)
 	if r0 != 0 {

src/pkg/syscall/ztypes_windows.go

@@ -924,3 +924,20 @@ const (
 	REG_DWORD = REG_DWORD_LITTLE_ENDIAN
 	REG_QWORD = REG_QWORD_LITTLE_ENDIAN
 )
+
+type AddrinfoW struct {
+	Flags     int32
+	Family    int32
+	Socktype  int32
+	Protocol  int32
+	Addrlen   uintptr
+	Canonname *uint16
+	Addr      uintptr
+	Next      *AddrinfoW
+}
+
+const (
+	AI_PASSIVE     = 1
+	AI_CANONNAME   = 2
+	AI_NUMERICHOST = 4
+)