Deprecate bufferSize

internal/cli/run_proxy.go

 	tcpTimeout := conf.Network.Timeout.TCP.Get(network.DefaultTimeout)
 	httpTimeout := conf.Network.Timeout.HTTP.Get(network.DefaultHTTPTimeout)
 	dohIP := conf.Network.DOHIP.Get(net.ParseIP(network.DefaultDOHHostname)).String()
-	bufferSize := conf.TCPBuffer.Get(network.DefaultBufferSize)
 	userAgent := "mtg/" + version
 
-	baseDialer, err := network.NewDefaultDialer(tcpTimeout, int(bufferSize))
+	baseDialer, err := network.NewDefaultDialer(tcpTimeout, 0)
 	if err != nil {
 		return nil, fmt.Errorf("cannot build a default dialer: %w", err)
 	}
 		EventStream:     eventStream,
 
 		Secret:             conf.Secret,
-		BufferSize:         conf.TCPBuffer.Get(mtglib.DefaultBufferSize),
 		DomainFrontingPort: conf.DomainFrontingPort.Get(mtglib.DefaultDomainFrontingPort),
 		PreferIP:           conf.PreferIP.Get(mtglib.DefaultPreferIP),
 
 		return fmt.Errorf("cannot create a proxy: %w", err)
 	}
 
-	listener, err := utils.NewListener(conf.BindTo.Get(""), int(opts.BufferSize))
+	listener, err := utils.NewListener(conf.BindTo.Get(""), 0)
 	if err != nil {
 		return fmt.Errorf("cannot start proxy: %w", err)
 	}

internal/cli/simple_run.go

 		return fmt.Errorf("incorrect concurrency: %w", err)
 	}
 
-	if err := conf.TCPBuffer.Set(s.TCPBuffer); err != nil {
-		return fmt.Errorf("incorrect tcp-buffer: %w", err)
-	}
-
 	if err := conf.PreferIP.Set(s.PreferIP); err != nil {
 		return fmt.Errorf("incorrect prefer-ip: %w", err)
 	}

internal/config/config.go

 	AllowFallbackOnUnknownDC TypeBool        `json:"allowFallbackOnUnknownDc"`
 	Secret                   mtglib.Secret   `json:"secret"`
 	BindTo                   TypeHostPort    `json:"bindTo"`
-	TCPBuffer                TypeBytes       `json:"tcpBuffer"`
 	PreferIP                 TypePreferIP    `json:"preferIp"`
 	DomainFrontingPort       TypePort        `json:"domainFrontingPort"`
 	TolerateTimeSkewness     TypeDuration    `json:"tolerateTimeSkewness"`

internal/config/parse.go

 	AllowFallbackOnUnknownDC bool   `toml:"allow-fallback-on-unknown-dc" json:"allowFallbackOnUnknownDc,omitempty"`
 	Secret                   string `toml:"secret" json:"secret"`
 	BindTo                   string `toml:"bind-to" json:"bindTo"`
-	TCPBuffer                string `toml:"tcp-buffer" json:"tcpBuffer,omitempty"`
 	PreferIP                 string `toml:"prefer-ip" json:"preferIp,omitempty"`
 	DomainFrontingPort       uint   `toml:"domain-fronting-port" json:"domainFrontingPort,omitempty"`
 	TolerateTimeSkewness     string `toml:"tolerate-time-skewness" json:"tolerateTimeSkewness,omitempty"`

internal/utils/net_listener.go

 
 type Listener struct {
 	net.Listener
-
-	bufferSize int
 }
 
 func (l Listener) Accept() (net.Conn, error) {
 		return nil, err // nolint: wrapcheck
 	}
 
-	if err := network.SetClientSocketOptions(conn, l.bufferSize); err != nil {
+	if err := network.SetClientSocketOptions(conn, 0); err != nil {
 		conn.Close()
 
 		return nil, fmt.Errorf("cannot set TCP options: %w", err)
 	}
 
 	return Listener{
-		Listener:   base,
-		bufferSize: bufferSize,
+		Listener: base,
 	}, nil
 }

mtglib/proxy_opts.go

 	// buffers: to and from.
 	//
 	// This is an optional setting.
+	//
+	// Deprecated: this setting is no longer makes any effect.
 	BufferSize uint
 
 	// Concurrency is a size of the worker pool for connection management.

network/default.go

 
 type defaultDialer struct {
 	net.Dialer
-
-	bufferSize int
 }
 
 func (d *defaultDialer) Dial(network, address string) (net.Conn, error) {
 	}
 
 	// we do not need to call to end user. End users call us.
-	if err := SetServerSocketOptions(conn, d.bufferSize); err != nil {
+	if err := SetServerSocketOptions(conn, 0); err != nil {
 		conn.Close()
 
 		return nil, fmt.Errorf("cannot set socket options: %w", err)
 //
 // The most default one you can imagine. But it has tunes TCP
 // connections and setups SO_REUSEPORT.
+//
+// bufferSize is deprecated and ignored. It is kept here for backward
+// compatibility.
 func NewDefaultDialer(timeout time.Duration, bufferSize int) (Dialer, error) {
 	switch {
 	case timeout < 0:
 		return nil, fmt.Errorf("timeout %v should be positive number", timeout)
-	case bufferSize < 0:
-		return nil, fmt.Errorf("buffer size %d should be positive number", bufferSize)
-	}
-
-	if timeout == 0 {
+	case timeout == 0:
 		timeout = DefaultTimeout
 	}
 
-	if bufferSize == 0 {
-		bufferSize = DefaultBufferSize
-	}
-
 	return &defaultDialer{
 		Dialer: net.Dialer{
 			Timeout: timeout,
 		},
-		bufferSize: bufferSize,
 	}, nil
 }

network/init.go

 	// request.
 	DefaultHTTPTimeout = 10 * time.Second
 
+	// Deprecated:
+	//
 	// DefaultBufferSize defines a TCP buffer size. Both read and write, so
 	// for real size, please multiply this number by 2.
 	DefaultBufferSize = 16 * 1024 // 16 kib
 
+	// DefaultTCPKeepAlivePeriod defines a time period between 2
+	// consequitive probes.
+	DefaultTCPKeepAlivePeriod = 10 * time.Second
+
 	// ProxyDialerOpenThreshold is used for load balancing SOCKS5 dialer
 	// only.
 	//

network/sockopts.go

 
 // SetClientSocketOptions tunes a TCP socket that represents a connection to
 // end user (not Telegram service or fronting domain).
+//
+// bufferSize setting is deprecated and ignored.
 func SetClientSocketOptions(conn net.Conn, bufferSize int) error {
-	tcpConn := conn.(*net.TCPConn) // nolint: forcetypeassert
-
-	if err := tcpConn.SetNoDelay(false); err != nil {
-		return fmt.Errorf("cannot disable TCP_NO_DELAY: %w", err)
-	}
-
-	return setCommonSocketOptions(tcpConn, bufferSize)
+	return setCommonSocketOptions(conn.(*net.TCPConn))
 }
 
 // SetServerSocketOptions tunes a TCP socket that represents a connection to
 // remote server like Telegram or fronting domain (but not end user).
 func SetServerSocketOptions(conn net.Conn, bufferSize int) error {
-	tcpConn := conn.(*net.TCPConn) // nolint: forcetypeassert
-
-	if err := tcpConn.SetNoDelay(true); err != nil {
-		return fmt.Errorf("cannot enable TCP_NO_DELAY: %w", err)
-	}
-
-	return setCommonSocketOptions(tcpConn, bufferSize)
+	return setCommonSocketOptions(conn.(*net.TCPConn))
 }
 
-func setCommonSocketOptions(conn *net.TCPConn, bufferSize int) error {
-	if err := conn.SetReadBuffer(bufferSize); err != nil {
-		return fmt.Errorf("cannot set read buffer size: %w", err)
-	}
-
-	if err := conn.SetWriteBuffer(bufferSize); err != nil {
-		return fmt.Errorf("cannot set write buffer size: %w", err)
+func setCommonSocketOptions(conn *net.TCPConn) error {
+	if err := conn.SetKeepAlive(true); err != nil {
+		return fmt.Errorf("cannot disable TCP keepalive probes: %w", err)
 	}
 
-	if err := conn.SetKeepAlive(false); err != nil {
-		return fmt.Errorf("cannot disable TCP keepalive probes: %w", err)
+	if err := conn.SetKeepAlivePeriod(DefaultTCPKeepAlivePeriod); err != nil {
+		return fmt.Errorf("cannot set time period of TCP keepalive probes: %w", err)
 	}
 
 	if err := conn.SetLinger(tcpLingerTimeout); err != nil {
 		return fmt.Errorf("cannot get underlying raw connection: %w", err)
 	}
 
-	if err := setSocketReuseAddrPort(rawConn, bufferSize); err != nil {
+	if err := setSocketReuseAddrPort(rawConn); err != nil {
 		return fmt.Errorf("cannot setup SO_REUSEADDR/PORT: %w", err)
 	}
 

network/sockopts_unix.go

 	"golang.org/x/sys/unix"
 )
 
-func setSocketReuseAddrPort(conn syscall.RawConn, bufferSize int) error {
+func setSocketReuseAddrPort(conn syscall.RawConn) error {
 	var err error
 
 	conn.Control(func(fd uintptr) { // nolint: errcheck

network/sockopts_windows.go

 
 import "syscall"
 
-func setSocketReuseAddrPort(conn syscall.RawConn, bufferSize int) error {
+func setSocketReuseAddrPort(conn syscall.RawConn) error {
 	return nil
 }