Carl Mastrangelo | 4aca796 | 2015-10-05 16:17:47 -0700 | [diff] [blame^] | 1 | package http2interop |
| 2 | |
| 3 | import ( |
| 4 | "encoding/binary" |
| 5 | "fmt" |
| 6 | "io" |
| 7 | ) |
| 8 | |
| 9 | type FrameHeader struct { |
| 10 | Length int |
| 11 | Type FrameType |
| 12 | Flags byte |
| 13 | Reserved Reserved |
| 14 | StreamID |
| 15 | } |
| 16 | |
| 17 | type Reserved bool |
| 18 | |
| 19 | func (r Reserved) String() string { |
| 20 | if r { |
| 21 | return "R" |
| 22 | } |
| 23 | return "" |
| 24 | } |
| 25 | |
| 26 | func (fh *FrameHeader) Parse(r io.Reader) error { |
| 27 | buf := make([]byte, 9) |
| 28 | if _, err := io.ReadFull(r, buf); err != nil { |
| 29 | return err |
| 30 | } |
| 31 | return fh.UnmarshalBinary(buf) |
| 32 | } |
| 33 | |
| 34 | func (fh *FrameHeader) UnmarshalBinary(b []byte) error { |
| 35 | if len(b) != 9 { |
| 36 | return fmt.Errorf("Invalid frame header length %d", len(b)) |
| 37 | } |
| 38 | *fh = FrameHeader{ |
| 39 | Length: int(b[0])<<16 | int(b[1])<<8 | int(b[2]), |
| 40 | Type: FrameType(b[3]), |
| 41 | Flags: b[4], |
| 42 | Reserved: Reserved(b[5]>>7 == 1), |
| 43 | StreamID: StreamID(binary.BigEndian.Uint32(b[5:9]) & 0x7fffffff), |
| 44 | } |
| 45 | return nil |
| 46 | } |
| 47 | |
| 48 | func (fh *FrameHeader) MarshalBinary() ([]byte, error) { |
| 49 | buf := make([]byte, 9, 9+fh.Length) |
| 50 | |
| 51 | if fh.Length > 0xFFFFFF || fh.Length < 0 { |
| 52 | return nil, fmt.Errorf("Invalid frame header length: %d", fh.Length) |
| 53 | } |
| 54 | if fh.StreamID < 0 { |
| 55 | return nil, fmt.Errorf("Invalid Stream ID: %v", fh.StreamID) |
| 56 | } |
| 57 | |
| 58 | buf[0], buf[1], buf[2] = byte(fh.Length>>16), byte(fh.Length>>8), byte(fh.Length) |
| 59 | buf[3] = byte(fh.Type) |
| 60 | buf[4] = fh.Flags |
| 61 | binary.BigEndian.PutUint32(buf[5:], uint32(fh.StreamID)) |
| 62 | |
| 63 | return buf, nil |
| 64 | } |
| 65 | |
| 66 | type StreamID int32 |
| 67 | |
| 68 | type FrameType byte |
| 69 | |
| 70 | func (ft FrameType) String() string { |
| 71 | switch ft { |
| 72 | case DataFrameType: |
| 73 | return "DATA" |
| 74 | case HeadersFrameType: |
| 75 | return "HEADERS" |
| 76 | case PriorityFrameType: |
| 77 | return "PRIORITY" |
| 78 | case ResetStreamFrameType: |
| 79 | return "RST_STREAM" |
| 80 | case SettingsFrameType: |
| 81 | return "SETTINGS" |
| 82 | case PushPromiseFrameType: |
| 83 | return "PUSH_PROMISE" |
| 84 | case PingFrameType: |
| 85 | return "PING" |
| 86 | case GoAwayFrameType: |
| 87 | return "GOAWAY" |
| 88 | case WindowUpdateFrameType: |
| 89 | return "WINDOW_UPDATE" |
| 90 | case ContinuationFrameType: |
| 91 | return "CONTINUATION" |
| 92 | default: |
| 93 | return fmt.Sprintf("UNKNOWN(%d)", byte(ft)) |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | // Types |
| 98 | const ( |
| 99 | DataFrameType FrameType = 0 |
| 100 | HeadersFrameType FrameType = 1 |
| 101 | PriorityFrameType FrameType = 2 |
| 102 | ResetStreamFrameType FrameType = 3 |
| 103 | SettingsFrameType FrameType = 4 |
| 104 | PushPromiseFrameType FrameType = 5 |
| 105 | PingFrameType FrameType = 6 |
| 106 | GoAwayFrameType FrameType = 7 |
| 107 | WindowUpdateFrameType FrameType = 8 |
| 108 | ContinuationFrameType FrameType = 9 |
| 109 | ) |