func handleConnection(conn *ss.Conn, auth bool) { var host string connCnt++ // this maybe not accurate, but should be enough if connCnt-nextLogConnCnt >= 0 { // XXX There's no xadd in the atomic package, so it's difficult to log // the message only once with low cost. Also note nextLogConnCnt maybe // added twice for current peak connection number level. log.Printf("Number of client connections reaches %d\n", nextLogConnCnt) nextLogConnCnt += logCntDelta } // function arguments are always evaluated, so surround debug statement // with if statement if debug { debug.Printf("new client %s->%s\n", conn.RemoteAddr().String(), conn.LocalAddr()) } closed := false defer func() { if debug { debug.Printf("closed pipe %s<->%s\n", conn.RemoteAddr(), host) } connCnt-- if !closed { conn.Close() } }() host, ota, err := getRequest(conn, auth) if err != nil { log.Println("error getting request", conn.RemoteAddr(), conn.LocalAddr(), err) return } debug.Println("connecting", host) remote, err := net.Dial("tcp", host) if err != nil { if ne, ok := err.(*net.OpError); ok && (ne.Err == syscall.EMFILE || ne.Err == syscall.ENFILE) { // log too many open file error // EMFILE is process reaches open file limits, ENFILE is system limit log.Println("dial error:", err) } else { log.Println("error connecting to:", host, err) } return } defer func() { if !closed { remote.Close() } }() if debug { debug.Printf("piping %s<->%s ota=%v connOta=%v", conn.RemoteAddr(), host, ota, conn.IsOta()) } if ota { go ss.PipeThenCloseOta(conn, remote) } else { go ss.PipeThenClose(conn, remote) } ss.PipeThenClose(remote, conn) closed = true return }