144 lines
3.7 KiB
Go
144 lines
3.7 KiB
Go
package wire
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import (
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"bytes"
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"errors"
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"fmt"
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"reflect"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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"github.com/lucas-clemente/quic-go/internal/qerr"
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)
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type frameParser struct {
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ackDelayExponent uint8
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supportsDatagrams bool
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version protocol.VersionNumber
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}
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// NewFrameParser creates a new frame parser.
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func NewFrameParser(supportsDatagrams bool, v protocol.VersionNumber) FrameParser {
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return &frameParser{
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supportsDatagrams: supportsDatagrams,
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version: v,
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}
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}
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// ParseNext parses the next frame.
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// It skips PADDING frames.
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func (p *frameParser) ParseNext(r *bytes.Reader, encLevel protocol.EncryptionLevel) (Frame, error) {
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for r.Len() != 0 {
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typeByte, _ := r.ReadByte()
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if typeByte == 0x0 { // PADDING frame
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continue
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}
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r.UnreadByte()
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f, err := p.parseFrame(r, typeByte, encLevel)
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if err != nil {
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return nil, &qerr.TransportError{
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FrameType: uint64(typeByte),
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ErrorCode: qerr.FrameEncodingError,
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ErrorMessage: err.Error(),
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}
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}
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return f, nil
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}
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return nil, nil
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}
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func (p *frameParser) parseFrame(r *bytes.Reader, typeByte byte, encLevel protocol.EncryptionLevel) (Frame, error) {
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var frame Frame
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var err error
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if typeByte&0xf8 == 0x8 {
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frame, err = parseStreamFrame(r, p.version)
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} else {
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switch typeByte {
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case 0x1:
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frame, err = parsePingFrame(r, p.version)
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case 0x2, 0x3:
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ackDelayExponent := p.ackDelayExponent
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if encLevel != protocol.Encryption1RTT {
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ackDelayExponent = protocol.DefaultAckDelayExponent
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}
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frame, err = parseAckFrame(r, ackDelayExponent, p.version)
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case 0x4:
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frame, err = parseResetStreamFrame(r, p.version)
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case 0x5:
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frame, err = parseStopSendingFrame(r, p.version)
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case 0x6:
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frame, err = parseCryptoFrame(r, p.version)
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case 0x7:
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frame, err = parseNewTokenFrame(r, p.version)
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case 0x10:
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frame, err = parseMaxDataFrame(r, p.version)
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case 0x11:
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frame, err = parseMaxStreamDataFrame(r, p.version)
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case 0x12, 0x13:
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frame, err = parseMaxStreamsFrame(r, p.version)
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case 0x14:
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frame, err = parseDataBlockedFrame(r, p.version)
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case 0x15:
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frame, err = parseStreamDataBlockedFrame(r, p.version)
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case 0x16, 0x17:
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frame, err = parseStreamsBlockedFrame(r, p.version)
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case 0x18:
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frame, err = parseNewConnectionIDFrame(r, p.version)
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case 0x19:
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frame, err = parseRetireConnectionIDFrame(r, p.version)
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case 0x1a:
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frame, err = parsePathChallengeFrame(r, p.version)
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case 0x1b:
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frame, err = parsePathResponseFrame(r, p.version)
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case 0x1c, 0x1d:
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frame, err = parseConnectionCloseFrame(r, p.version)
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case 0x1e:
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frame, err = parseHandshakeDoneFrame(r, p.version)
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case 0x30, 0x31:
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if p.supportsDatagrams {
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frame, err = parseDatagramFrame(r, p.version)
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break
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}
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fallthrough
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default:
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err = errors.New("unknown frame type")
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}
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}
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if err != nil {
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return nil, err
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}
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if !p.isAllowedAtEncLevel(frame, encLevel) {
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return nil, fmt.Errorf("%s not allowed at encryption level %s", reflect.TypeOf(frame).Elem().Name(), encLevel)
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}
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return frame, nil
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}
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func (p *frameParser) isAllowedAtEncLevel(f Frame, encLevel protocol.EncryptionLevel) bool {
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switch encLevel {
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case protocol.EncryptionInitial, protocol.EncryptionHandshake:
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switch f.(type) {
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case *CryptoFrame, *AckFrame, *ConnectionCloseFrame, *PingFrame:
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return true
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default:
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return false
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}
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case protocol.Encryption0RTT:
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switch f.(type) {
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case *CryptoFrame, *AckFrame, *ConnectionCloseFrame, *NewTokenFrame, *PathResponseFrame, *RetireConnectionIDFrame:
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return false
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default:
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return true
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}
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case protocol.Encryption1RTT:
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return true
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default:
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panic("unknown encryption level")
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}
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}
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func (p *frameParser) SetAckDelayExponent(exp uint8) {
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p.ackDelayExponent = exp
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}
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