package obfs import ( "bytes" "encoding/base64" "fmt" "io" "math/rand" "net" "net/http" B "github.com/sagernet/sing/common/buf" ) // HTTPObfs is shadowsocks http simple-obfs implementation type HTTPObfs struct { net.Conn host string port string buf []byte offset int firstRequest bool firstResponse bool } func (ho *HTTPObfs) Read(b []byte) (int, error) { if ho.buf != nil { n := copy(b, ho.buf[ho.offset:]) ho.offset += n if ho.offset == len(ho.buf) { B.Put(ho.buf) ho.buf = nil } return n, nil } if ho.firstResponse { buf := B.Get(B.BufferSize) n, err := ho.Conn.Read(buf) if err != nil { B.Put(buf) return 0, err } idx := bytes.Index(buf[:n], []byte("\r\n\r\n")) if idx == -1 { B.Put(buf) return 0, io.EOF } ho.firstResponse = false length := n - (idx + 4) n = copy(b, buf[idx+4:n]) if length > n { ho.buf = buf[:idx+4+length] ho.offset = idx + 4 + n } else { B.Put(buf) } return n, nil } return ho.Conn.Read(b) } func (ho *HTTPObfs) Write(b []byte) (int, error) { if ho.firstRequest { randBytes := make([]byte, 16) rand.Read(randBytes) req, _ := http.NewRequest("GET", fmt.Sprintf("http://%s/", ho.host), bytes.NewBuffer(b[:])) req.Header.Set("User-Agent", fmt.Sprintf("curl/7.%d.%d", rand.Int()%54, rand.Int()%2)) req.Header.Set("Upgrade", "websocket") req.Header.Set("Connection", "Upgrade") req.Host = ho.host if ho.port != "80" { req.Host = fmt.Sprintf("%s:%s", ho.host, ho.port) } req.Header.Set("Sec-WebSocket-Key", base64.URLEncoding.EncodeToString(randBytes)) req.ContentLength = int64(len(b)) err := req.Write(ho.Conn) ho.firstRequest = false return len(b), err } return ho.Conn.Write(b) } // NewHTTPObfs return a HTTPObfs func NewHTTPObfs(conn net.Conn, host string, port string) net.Conn { return &HTTPObfs{ Conn: conn, firstRequest: true, firstResponse: true, host: host, port: port, } }