net: set IsNotFound for unknown services in LookupPort

Change-Id: I9d5f0ea5edd2c121179e3d2f8d4a890fa25a3fa9
GitHub-Last-Rev: 48a13fe5f5
GitHub-Pull-Request: golang/go#63160
Reviewed-on: https://go-review.googlesource.com/c/go/+/530415
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/internal/syscall/unix/net_darwin.go

@@ -19,6 +19,7 @@ const (
 	EAI_AGAIN    = 2
 	EAI_NODATA   = 7
 	EAI_NONAME   = 8
+	EAI_SERVICE  = 9
 	EAI_SYSTEM   = 11
 	EAI_OVERFLOW = 14
 

src/net/cgo_unix.go

@@ -120,6 +120,8 @@ func cgoLookupServicePort(hints *_C_struct_addrinfo, network, service string) (p
 			if err == nil { // see golang.org/issue/6232
 				err = syscall.EMFILE
 			}
+		case _C_EAI_SERVICE, _C_EAI_NONAME: // Darwin returns EAI_NONAME.
+			return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 		default:
 			err = addrinfoErrno(gerrno)
 			isTemporary = addrinfoErrno(gerrno).Temporary()
@@ -140,7 +142,7 @@ func cgoLookupServicePort(hints *_C_struct_addrinfo, network, service string) (p
 			return int(p[0])<<8 | int(p[1]), nil
 		}
 	}
-	return 0, &DNSError{Err: "unknown port", Name: network + "/" + service}
+	return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 }
 
 func cgoLookupHostIP(network, name string) (addrs []IPAddr, err error) {

src/net/cgo_unix_cgo.go

@@ -37,6 +37,7 @@ const (
 	_C_EAI_AGAIN    = C.EAI_AGAIN
 	_C_EAI_NODATA   = C.EAI_NODATA
 	_C_EAI_NONAME   = C.EAI_NONAME
+	_C_EAI_SERVICE  = C.EAI_SERVICE
 	_C_EAI_OVERFLOW = C.EAI_OVERFLOW
 	_C_EAI_SYSTEM   = C.EAI_SYSTEM
 	_C_IPPROTO_TCP  = C.IPPROTO_TCP

src/net/cgo_unix_syscall.go

@@ -19,6 +19,7 @@ const (
 	_C_AF_UNSPEC    = syscall.AF_UNSPEC
 	_C_EAI_AGAIN    = unix.EAI_AGAIN
 	_C_EAI_NONAME   = unix.EAI_NONAME
+	_C_EAI_SERVICE  = unix.EAI_SERVICE
 	_C_EAI_NODATA   = unix.EAI_NODATA
 	_C_EAI_OVERFLOW = unix.EAI_OVERFLOW
 	_C_EAI_SYSTEM   = unix.EAI_SYSTEM

src/net/lookup.go

@@ -96,8 +96,9 @@ func lookupPortMap(network, service string) (port int, error error) {
 		if port, ok := m[string(lowerService[:n])]; ok && n == len(service) {
 			return port, nil
 		}
+		return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 	}
-	return 0, &AddrError{Err: "unknown port", Addr: network + "/" + service}
+	return 0, &DNSError{Err: "unknown network", Name: network + "/" + service}
 }
 
 // ipVersion returns the provided network's IP version: '4', '6' or 0

src/net/lookup_plan9.go

@@ -212,15 +212,17 @@ func (*Resolver) lookupPort(ctx context.Context, network, service string) (port
 	}
 	lines, err := queryCS(ctx, network, "127.0.0.1", toLower(service))
 	if err != nil {
+		if stringsHasSuffix(err.Error(), "can't translate service") {
+			return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
+		}
 		return
 	}
-	unknownPortError := &AddrError{Err: "unknown port", Addr: network + "/" + service}
 	if len(lines) == 0 {
-		return 0, unknownPortError
+		return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 	}
 	f := getFields(lines[0])
 	if len(f) < 2 {
-		return 0, unknownPortError
+		return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 	}
 	s := f[1]
 	if i := bytealg.IndexByteString(s, '!'); i >= 0 {
@@ -229,7 +231,7 @@ func (*Resolver) lookupPort(ctx context.Context, network, service string) (port
 	if n, _, ok := dtoi(s); ok {
 		return n, nil
 	}
-	return 0, unknownPortError
+	return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 }
 
 func (r *Resolver) lookupCNAME(ctx context.Context, name string) (cname string, err error) {

src/net/lookup_test.go

@@ -1460,3 +1460,11 @@ func testLookupNoData(t *testing.T, prefix string) {
 		return
 	}
 }
+
+func TestLookupPortNotFound(t *testing.T) {
+	_, err := LookupPort("udp", "_-unknown-service-")
+	var dnsErr *DNSError
+	if !errors.As(err, &dnsErr) || !dnsErr.IsNotFound {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}

src/net/lookup_windows.go

@@ -22,6 +22,7 @@ const cgoAvailable = true
 const (
 	_WSAHOST_NOT_FOUND = syscall.Errno(11001)
 	_WSATRY_AGAIN      = syscall.Errno(11002)
+	_WSATYPE_NOT_FOUND = syscall.Errno(10109)
 )
 
 func winError(call string, err error) error {
@@ -217,12 +218,16 @@ func (r *Resolver) lookupPort(ctx context.Context, network, service string) (int
 		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
+
+		// The _WSATYPE_NOT_FOUND error is returned by GetAddrInfoW
+		// when the service name is unknown. We are also checking
+		// for _WSAHOST_NOT_FOUND here to match the cgo (unix) version
+		// cgo_unix.go (cgoLookupServicePort).
+		if e == _WSATYPE_NOT_FOUND || e == _WSAHOST_NOT_FOUND {
+			return 0, &DNSError{Err: "unknown port", Name: network + "/" + service, IsNotFound: true}
 		}
-		return 0, dnsError
+		err := os.NewSyscallError("getaddrinfow", e)
+		return 0, &DNSError{Err: err.Error(), Name: network + "/" + service}
 	}
 	defer syscall.FreeAddrInfoW(result)
 	if result == nil {