libgo: update to go1.9

    
    Reviewed-on: https://go-review.googlesource.com/63753

From-SVN: r252767

1 files changed, 39 insertions, 5 deletions

diff --git a/libgo/go/net/lookup.go b/libgo/go/net/lookup.go
index cc2013e..c9f3270 100644
--- a/libgo/go/net/lookup.go
+++ b/libgo/go/net/lookup.go
@@ -28,6 +28,9 @@ var protocols = map[string]int{
 // services contains minimal mappings between services names and port
 // numbers for platforms that don't have a complete list of port numbers
 // (some Solaris distros, nacl, etc).
+//
+// See https://www.iana.org/assignments/service-names-port-numbers
+//
 // On Unix, this map is augmented by readServices via goLookupPort.
 var services = map[string]map[string]int{
 	"udp": {
@@ -63,7 +66,12 @@ func lookupProtocolMap(name string) (int, error) {
 	return proto, nil
 }
 
-const maxServiceLength = len("mobility-header") + 10 // with room to grow
+// maxPortBufSize is the longest reasonable name of a service
+// (non-numeric port).
+// Currently the longest known IANA-unregistered name is
+// "mobility-header", so we use that length, plus some slop in case
+// something longer is added in the future.
+const maxPortBufSize = len("mobility-header") + 10
 
 func lookupPortMap(network, service string) (port int, error error) {
 	switch network {
@@ -74,7 +82,7 @@ func lookupPortMap(network, service string) (port int, error error) {
 	}
 
 	if m, ok := services[network]; ok {
-		var lowerService [maxServiceLength]byte
+		var lowerService [maxPortBufSize]byte
 		n := copy(lowerService[:], service)
 		lowerASCIIBytes(lowerService[:n])
 		if port, ok := m[string(lowerService[:n])]; ok && n == len(service) {
@@ -97,6 +105,29 @@ type Resolver struct {
 	// GODEBUG=netdns=go, but scoped to just this resolver.
 	PreferGo bool
 
+	// StrictErrors controls the behavior of temporary errors
+	// (including timeout, socket errors, and SERVFAIL) when using
+	// Go's built-in resolver. For a query composed of multiple
+	// sub-queries (such as an A+AAAA address lookup, or walking the
+	// DNS search list), this option causes such errors to abort the
+	// whole query instead of returning a partial result. This is
+	// not enabled by default because it may affect compatibility
+	// with resolvers that process AAAA queries incorrectly.
+	StrictErrors bool
+
+	// Dial optionally specifies an alternate dialer for use by
+	// Go's built-in DNS resolver to make TCP and UDP connections
+	// to DNS services. The host in the address parameter will
+	// always be a literal IP address and not a host name, and the
+	// port in the address parameter will be a literal port number
+	// and not a service name.
+	// If the Conn returned is also a PacketConn, sent and received DNS
+	// messages must adhere to RFC 1035 section 4.2.1, "UDP usage".
+	// Otherwise, DNS messages transmitted over Conn must adhere
+	// to RFC 7766 section 5, "Transport Protocol Selection".
+	// If nil, the default dialer is used.
+	Dial func(ctx context.Context, network, address string) (Conn, error)
+
 	// TODO(bradfitz): optional interface impl override hook
 	// TODO(bradfitz): Timeout time.Duration?
 }
@@ -164,12 +195,15 @@ func (r *Resolver) LookupIPAddr(ctx context.Context, host string) ([]IPAddr, err
 
 	select {
 	case <-ctx.Done():
-		// The DNS lookup timed out for some reason. Force
+		// If the DNS lookup timed out for some reason, force
 		// future requests to start the DNS lookup again
 		// rather than waiting for the current lookup to
 		// complete. See issue 8602.
-		err := mapErr(ctx.Err())
-		lookupGroup.Forget(host)
+		ctxErr := ctx.Err()
+		if ctxErr == context.DeadlineExceeded {
+			lookupGroup.Forget(host)
+		}
+		err := mapErr(ctxErr)
 		if trace != nil && trace.DNSDone != nil {
 			trace.DNSDone(nil, false, err)
 		}