sing-box/transport/clashssr/protocol/base.go

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package protocol
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"encoding/binary"
"math/rand"
"sync"
"time"
"github.com/Dreamacro/clash/common/pool"
"github.com/Dreamacro/clash/transport/shadowsocks/core"
)
type Base struct {
Key []byte
Overhead int
Param string
}
type userData struct {
userKey []byte
userID [4]byte
}
type authData struct {
clientID [4]byte
connectionID uint32
mutex sync.Mutex
}
func (a *authData) next() *authData {
r := &authData{}
a.mutex.Lock()
defer a.mutex.Unlock()
if a.connectionID > 0xff000000 || a.connectionID == 0 {
rand.Read(a.clientID[:])
a.connectionID = rand.Uint32() & 0xffffff
}
a.connectionID++
copy(r.clientID[:], a.clientID[:])
r.connectionID = a.connectionID
return r
}
func (a *authData) putAuthData(buf *bytes.Buffer) {
binary.Write(buf, binary.LittleEndian, uint32(time.Now().Unix()))
buf.Write(a.clientID[:])
binary.Write(buf, binary.LittleEndian, a.connectionID)
}
func (a *authData) putEncryptedData(b *bytes.Buffer, userKey []byte, paddings [2]int, salt string) error {
encrypt := pool.Get(16)
defer pool.Put(encrypt)
binary.LittleEndian.PutUint32(encrypt, uint32(time.Now().Unix()))
copy(encrypt[4:], a.clientID[:])
binary.LittleEndian.PutUint32(encrypt[8:], a.connectionID)
binary.LittleEndian.PutUint16(encrypt[12:], uint16(paddings[0]))
binary.LittleEndian.PutUint16(encrypt[14:], uint16(paddings[1]))
cipherKey := core.Kdf(base64.StdEncoding.EncodeToString(userKey)+salt, 16)
block, err := aes.NewCipher(cipherKey)
if err != nil {
return err
}
iv := bytes.Repeat([]byte{0}, 16)
cbcCipher := cipher.NewCBCEncrypter(block, iv)
cbcCipher.CryptBlocks(encrypt, encrypt)
b.Write(encrypt)
return nil
}