79 lines
2.2 KiB
Go
79 lines
2.2 KiB
Go
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package quic
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import (
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"fmt"
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"io"
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)
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// protocolSignature defines the first 6 bytes of the stream, which is used to distinguish the type of stream. It
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// ensures whoever performs a handshake does not write data before writing the metadata.
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type protocolSignature [6]byte
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var (
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// dataStreamProtocolSignature is a custom protocol signature for data stream
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dataStreamProtocolSignature = protocolSignature{0x0A, 0x36, 0xCD, 0x12, 0xA1, 0x3E}
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// rpcStreamProtocolSignature is a custom protocol signature for RPC stream
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rpcStreamProtocolSignature = protocolSignature{0x52, 0xBB, 0x82, 0x5C, 0xDB, 0x65}
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errDataStreamNotSupported = fmt.Errorf("data protocol not supported")
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errRPCStreamNotSupported = fmt.Errorf("rpc protocol not supported")
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)
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type protocolVersion string
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const (
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protocolV1 protocolVersion = "01"
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protocolVersionLength = 2
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)
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// determineProtocol reads the first 6 bytes from the stream to determine which protocol is spoken by the client.
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// The protocols are magic byte arrays understood by both sides of the stream.
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func determineProtocol(stream io.Reader) (protocolSignature, error) {
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signature, err := readSignature(stream)
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if err != nil {
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return protocolSignature{}, err
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}
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switch signature {
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case dataStreamProtocolSignature:
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return dataStreamProtocolSignature, nil
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case rpcStreamProtocolSignature:
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return rpcStreamProtocolSignature, nil
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default:
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return protocolSignature{}, fmt.Errorf("unknown signature %v", signature)
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}
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}
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func writeDataStreamPreamble(stream io.Writer) error {
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if err := writeSignature(stream, dataStreamProtocolSignature); err != nil {
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return err
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}
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return writeVersion(stream)
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}
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func writeVersion(stream io.Writer) error {
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_, err := stream.Write([]byte(protocolV1)[:protocolVersionLength])
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return err
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}
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func readVersion(stream io.Reader) (string, error) {
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version := make([]byte, protocolVersionLength)
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_, err := stream.Read(version)
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return string(version), err
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}
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func readSignature(stream io.Reader) (protocolSignature, error) {
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var signature protocolSignature
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if _, err := io.ReadFull(stream, signature[:]); err != nil {
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return protocolSignature{}, err
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}
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return signature, nil
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}
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func writeSignature(stream io.Writer, signature protocolSignature) error {
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_, err := stream.Write(signature[:])
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return err
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}
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