http2: reduce log spam, especially on Windows

Recognize connection aborted errors on Windows and don't log them by
default, like the Unix case.

Log frame reading errors only at verbose level, to match
net/http.Server.

Updates golang/go#13925
Updates golang/go#14061

Change-Id: I87998a924b11d4dad5512e010b29d2da6b4bf867
Reviewed-on: https://go-review.googlesource.com/18932
Reviewed-by: Ian Lance Taylor <iant@golang.org>

http2/server.go

@@ -48,6 +48,8 @@ import (
 	"net/http"
 	"net/textproto"
 	"net/url"
+	"os"
+	"reflect"
 	"runtime"
 	"strconv"
 	"strings"
@@ -482,12 +484,57 @@ func (sc *serverConn) logf(format string, args ...interface{}) {
 	}
 }
 
+var uintptrType = reflect.TypeOf(uintptr(0))
+
+// errno returns v's underlying uintptr, else 0.
+//
+// TODO: remove this helper function once http2 can use build
+// tags. See comment in isClosedConnError.
+func errno(v error) uintptr {
+	if rv := reflect.ValueOf(v); rv.Kind() == reflect.Uintptr {
+		return uintptr(rv.Uint())
+	}
+	return 0
+}
+
+// isClosedConnError reports whether err is an error from use of a closed
+// network connection.
+func isClosedConnError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// TODO: remove this string search and be more like the Windows
+	// case below. That might involve modifying the standard library
+	// to return better error types.
+	str := err.Error()
+	if strings.Contains(str, "use of closed network connection") {
+		return true
+	}
+
+	// TODO(bradfitz): x/tools/cmd/bundle doesn't really support
+	// build tags, so I can't make an http2_windows.go file with
+	// Windows-specific stuff. Fix that and move this, once we
+	// have a way to bundle this into std's net/http somehow.
+	if runtime.GOOS == "windows" {
+		if oe, ok := err.(*net.OpError); ok && oe.Op == "read" {
+			if se, ok := oe.Err.(*os.SyscallError); ok && se.Syscall == "wsarecv" {
+				const WSAECONNABORTED = 10053
+				const WSAECONNRESET = 10054
+				if n := errno(se.Err); n == WSAECONNRESET || n == WSAECONNABORTED {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
 func (sc *serverConn) condlogf(err error, format string, args ...interface{}) {
 	if err == nil {
 		return
 	}
-	str := err.Error()
-	if err == io.EOF || strings.Contains(str, "use of closed network connection") {
+	if err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err) {
 		// Boring, expected errors.
 		sc.vlogf(format, args...)
 	} else {
@@ -1031,7 +1078,7 @@ func (sc *serverConn) processFrameFromReader(res readFrameResult) bool {
 			sc.goAway(ErrCodeFrameSize)
 			return true // goAway will close the loop
 		}
-		clientGone := err == io.EOF || strings.Contains(err.Error(), "use of closed network connection")
+		clientGone := err == io.EOF || err == io.ErrUnexpectedEOF || isClosedConnError(err)
 		if clientGone {
 			// TODO: could we also get into this state if
 			// the peer does a half close
@@ -1067,7 +1114,7 @@ func (sc *serverConn) processFrameFromReader(res readFrameResult) bool {
 		return true // goAway will handle shutdown
 	default:
 		if res.err != nil {
-			sc.logf("http2: server closing client connection; error reading frame from client %s: %v", sc.conn.RemoteAddr(), err)
+			sc.vlogf("http2: server closing client connection; error reading frame from client %s: %v", sc.conn.RemoteAddr(), err)
 		} else {
 			sc.logf("http2: server closing client connection: %v", err)
 		}