clash/transport/ssr/protocol/protocol.go
2021-05-13 22:19:34 +08:00

76 lines
1.9 KiB
Go

package protocol
import (
"bytes"
"errors"
"fmt"
"math/rand"
"net"
)
var (
errAuthSHA1V4CRC32Error = errors.New("auth_sha1_v4 decode data wrong crc32")
errAuthSHA1V4LengthError = errors.New("auth_sha1_v4 decode data wrong length")
errAuthSHA1V4Adler32Error = errors.New("auth_sha1_v4 decode data wrong adler32")
errAuthAES128MACError = errors.New("auth_aes128 decode data wrong mac")
errAuthAES128LengthError = errors.New("auth_aes128 decode data wrong length")
errAuthAES128ChksumError = errors.New("auth_aes128 decode data wrong checksum")
errAuthChainLengthError = errors.New("auth_chain decode data wrong length")
errAuthChainChksumError = errors.New("auth_chain decode data wrong checksum")
)
type Protocol interface {
StreamConn(net.Conn, []byte) net.Conn
PacketConn(net.PacketConn) net.PacketConn
Decode(dst, src *bytes.Buffer) error
Encode(buf *bytes.Buffer, b []byte) error
DecodePacket([]byte) ([]byte, error)
EncodePacket(buf *bytes.Buffer, b []byte) error
}
type protocolCreator func(b *Base) Protocol
var protocolList = make(map[string]struct {
overhead int
new protocolCreator
})
func register(name string, c protocolCreator, o int) {
protocolList[name] = struct {
overhead int
new protocolCreator
}{overhead: o, new: c}
}
func PickProtocol(name string, b *Base) (Protocol, error) {
if choice, ok := protocolList[name]; ok {
b.Overhead += choice.overhead
return choice.new(b), nil
}
return nil, fmt.Errorf("protocol %s not supported", name)
}
func getHeadSize(b []byte, defaultValue int) int {
if len(b) < 2 {
return defaultValue
}
headType := b[0] & 7
switch headType {
case 1:
return 7
case 4:
return 19
case 3:
return 4 + int(b[1])
}
return defaultValue
}
func getDataLength(b []byte) int {
bLength := len(b)
dataLength := getHeadSize(b, 30) + rand.Intn(32)
if bLength < dataLength {
return bLength
}
return dataLength
}