1 files changed, 109 insertions, 0 deletions
diff --git a/tools/http2_interop/frameheader.go b/tools/http2_interop/frameheader.go
new file mode 100644
index 0000000000..78fe4201f6
--- /dev/null
+++ b/tools/http2_interop/frameheader.go
@@ -0,0 +1,109 @@
+package http2interop
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+type FrameHeader struct {
+	Length   int
+	Type     FrameType
+	Flags    byte
+	Reserved Reserved
+	StreamID
+}
+
+type Reserved bool
+
+func (r Reserved) String() string {
+	if r {
+		return "R"
+	}
+	return ""
+}
+
+func (fh *FrameHeader) Parse(r io.Reader) error {
+	buf := make([]byte, 9)
+	if _, err := io.ReadFull(r, buf); err != nil {
+		return err
+	}
+	return fh.UnmarshalBinary(buf)
+}
+
+func (fh *FrameHeader) UnmarshalBinary(b []byte) error {
+	if len(b) != 9 {
+		return fmt.Errorf("Invalid frame header length %d", len(b))
+	}
+	*fh = FrameHeader{
+		Length:   int(b[0])<<16 | int(b[1])<<8 | int(b[2]),
+		Type:     FrameType(b[3]),
+		Flags:    b[4],
+		Reserved: Reserved(b[5]>>7 == 1),
+		StreamID: StreamID(binary.BigEndian.Uint32(b[5:9]) & 0x7fffffff),
+	}
+	return nil
+}
+
+func (fh *FrameHeader) MarshalBinary() ([]byte, error) {
+	buf := make([]byte, 9, 9+fh.Length)
+
+	if fh.Length > 0xFFFFFF || fh.Length < 0 {
+		return nil, fmt.Errorf("Invalid frame header length: %d", fh.Length)
+	}
+	if fh.StreamID < 0 {
+		return nil, fmt.Errorf("Invalid Stream ID: %v", fh.StreamID)
+	}
+
+	buf[0], buf[1], buf[2] = byte(fh.Length>>16), byte(fh.Length>>8), byte(fh.Length)
+	buf[3] = byte(fh.Type)
+	buf[4] = fh.Flags
+	binary.BigEndian.PutUint32(buf[5:], uint32(fh.StreamID))
+
+	return buf, nil
+}
+
+type StreamID int32
+
+type FrameType byte
+
+func (ft FrameType) String() string {
+	switch ft {
+	case DataFrameType:
+		return "DATA"
+	case HeadersFrameType:
+		return "HEADERS"
+	case PriorityFrameType:
+		return "PRIORITY"
+	case ResetStreamFrameType:
+		return "RST_STREAM"
+	case SettingsFrameType:
+		return "SETTINGS"
+	case PushPromiseFrameType:
+		return "PUSH_PROMISE"
+	case PingFrameType:
+		return "PING"
+	case GoAwayFrameType:
+		return "GOAWAY"
+	case WindowUpdateFrameType:
+		return "WINDOW_UPDATE"
+	case ContinuationFrameType:
+		return "CONTINUATION"
+	default:
+		return fmt.Sprintf("UNKNOWN(%d)", byte(ft))
+	}
+}
+
+// Types
+const (
+	DataFrameType         FrameType = 0
+	HeadersFrameType      FrameType = 1
+	PriorityFrameType     FrameType = 2
+	ResetStreamFrameType  FrameType = 3
+	SettingsFrameType     FrameType = 4
+	PushPromiseFrameType  FrameType = 5
+	PingFrameType         FrameType = 6
+	GoAwayFrameType       FrameType = 7
+	WindowUpdateFrameType FrameType = 8
+	ContinuationFrameType FrameType = 9
+)