// controlFrameCommonProcessing performs checks identical between
// all control frames. This includes the control bit, the version
// number, the type byte (which is checked against the byte
// provided), and the flags (which are checked against the bitwise
// OR of valid flags provided).
func controlFrameCommonProcessing(data []byte, frameType uint16, flags byte) error {
// Check it's a control frame.
if data[0] != 128 {
return common.IncorrectFrame(_DATA_FRAME, int(frameType), 2)
}
// Check version.
version := (uint16(data[0]&0x7f) << 8) + uint16(data[1])
if version != 2 {
return common.UnsupportedVersion(version)
}
// Check its type.
realType := common.BytesToUint16(data[2:])
if realType != frameType {
return common.IncorrectFrame(int(realType), int(frameType), 2)
}
// Check the flags.
if data[4] & ^flags != 0 {
return common.InvalidField("flags", int(data[4]), int(flags))
}
return nil
}
func (frame *CREDENTIAL) ReadFrom(reader io.Reader) (int64, error) {
c := common.ReadCounter{R: reader}
data, err := common.ReadExactly(&c, 18)
if err != nil {
return c.N, err
}
err = controlFrameCommonProcessing(data[:5], _CREDENTIAL, 0)
if err != nil {
return c.N, err
}
// Get and check length.
length := int(common.BytesToUint24(data[5:8]))
if length < 6 {
return c.N, common.IncorrectDataLength(length, 6)
} else if length > common.MAX_FRAME_SIZE-8 {
return c.N, common.FrameTooLarge
}
// Read in data.
certs, err := common.ReadExactly(&c, length-10)
if err != nil {
return c.N, err
}
frame.Slot = common.BytesToUint16(data[8:10])
proofLen := int(common.BytesToUint32(data[10:14]))
if proofLen > 0 {
frame.Proof = data[14 : 14+proofLen]
} else {
frame.Proof = []byte{}
}
numCerts := 0
for offset := 0; offset < length-10; {
offset += int(common.BytesToUint32(certs[offset:offset+4])) + 4
numCerts++
}
frame.Certificates = make([]*x509.Certificate, numCerts)
for i, offset := 0, 0; offset < length-10; i++ {
length := int(common.BytesToUint32(certs[offset : offset+4]))
rawCert := certs[offset+4 : offset+4+length]
frame.Certificates[i], err = x509.ParseCertificate(rawCert)
if err != nil {
return c.N, err
}
offset += length + 4
}
return c.N, nil
}
// ReadFrame reads and parses a frame from reader.
func ReadFrame(reader *bufio.Reader, subversion int) (frame common.Frame, err error) {
start, err := reader.Peek(4)
if err != nil {
return nil, err
}
if start[0] != 128 {
frame = new(DATA)
_, err = frame.ReadFrom(reader)
return frame, err
}
switch common.BytesToUint16(start[2:4]) {
case _SYN_STREAM:
switch subversion {
case 0:
frame = new(SYN_STREAM)
case 1:
frame = new(SYN_STREAMV3_1)
default:
return nil, fmt.Errorf("Error: Given subversion %d is unrecognised.", subversion)
}
case _SYN_REPLY:
frame = new(SYN_REPLY)
case _RST_STREAM:
frame = new(RST_STREAM)
case _SETTINGS:
frame = new(SETTINGS)
case _PING:
frame = new(PING)
case _GOAWAY:
frame = new(GOAWAY)
case _HEADERS:
frame = new(HEADERS)
case _WINDOW_UPDATE:
frame = &WINDOW_UPDATE{subversion: subversion}
case _CREDENTIAL:
frame = new(CREDENTIAL)
default:
return nil, errors.New("Error Failed to parse frame type.")
}
_, err = frame.ReadFrom(reader)
return frame, err
}
// ReadFrame reads and parses a frame from reader.
func ReadFrame(reader *bufio.Reader) (frame common.Frame, err error) {
start, err := reader.Peek(4)
if err != nil {
return nil, err
}
if start[0] != 128 {
frame = new(DATA)
_, err = frame.ReadFrom(reader)
return frame, err
}
switch common.BytesToUint16(start[2:4]) {
case _SYN_STREAM:
frame = new(SYN_STREAM)
case _SYN_REPLY:
frame = new(SYN_REPLY)
case _RST_STREAM:
frame = new(RST_STREAM)
case _SETTINGS:
frame = new(SETTINGS)
case _NOOP:
frame = new(NOOP)
case _PING:
frame = new(PING)
case _GOAWAY:
frame = new(GOAWAY)
case _HEADERS:
frame = new(HEADERS)
case _WINDOW_UPDATE:
frame = new(WINDOW_UPDATE)
default:
return nil, errors.New("Error Failed to parse frame type.")
}
_, err = frame.ReadFrom(reader)
return frame, err
}