cloudflared/tunnelrpc/quic/protocol.go
Devin Carr eb2e4349e8 TUN-8415: Refactor capnp rpc into a single module
Combines the tunnelrpc and quic/schema capnp files into the same module.

To help reduce future issues with capnp id generation, capnpids are
provided in the capnp files from the existing capnp struct ids generated
in the go files.

Reduces the overall interface of the Capnp methods to the rest of
the code by providing an interface that will handle the quic protocol
selection.

Introduces a new `rpc-timeout` config that will allow all of the
SessionManager and ConfigurationManager RPC requests to have a timeout.
The timeout for these values is set to 5 seconds as non of these operations
for the managers should take a long time to complete.

Removed the RPC-specific logger as it never provided good debugging value
as the RPC method names were not visible in the logs.
2024-05-17 11:22:07 -07:00

79 lines
2.2 KiB
Go

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