Feat: custom TCP Fast Open queue length (#1293)

* Feat: custom TCP Fast Open queue length

* Feat: change default TFO queue length to 4096

infra/conf/transport_internet.go

@@ -387,6 +387,7 @@ func (p TransportProtocol) Build() (string, error) {
 type SocketConfig struct {
 	Mark                 uint32 `json:"mark"`
 	TFO                  *bool  `json:"tcpFastOpen"`
+	TFOQueueLength       uint32 `json:"tcpFastOpenQueueLength"`
 	TProxy               string `json:"tproxy"`
 	AcceptProxyProtocol  bool   `json:"acceptProxyProtocol"`
 	TCPKeepAliveInterval int32  `json:"tcpKeepAliveInterval"`
@@ -402,6 +403,12 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 			tfoSettings = internet.SocketConfig_Disable
 		}
 	}
+
+	tfoQueueLength := c.TFOQueueLength
+	if tfoQueueLength == 0 {
+		tfoQueueLength = 4096
+	}
+
 	var tproxy internet.SocketConfig_TProxyMode
 	switch strings.ToLower(c.TProxy) {
 	case "tproxy":
@@ -415,6 +422,7 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 	return &internet.SocketConfig{
 		Mark:                 c.Mark,
 		Tfo:                  tfoSettings,
+		TfoQueueLength:       tfoQueueLength,
 		Tproxy:               tproxy,
 		AcceptProxyProtocol:  c.AcceptProxyProtocol,
 		TcpKeepAliveInterval: c.TCPKeepAliveInterval,

infra/conf/transport_test.go

@@ -35,12 +35,14 @@ func TestSocketConfig(t *testing.T) {
 		{
 			Input: `{
 				"mark": 1,
-				"tcpFastOpen": true
+				"tcpFastOpen": true,
+				"tcpFastOpenQueueLength": 1024
 			}`,
 			Parser: createParser(),
 			Output: &internet.SocketConfig{
-				Mark: 1,
-				Tfo:  internet.SocketConfig_Enable,
+				Mark:           1,
+				Tfo:            internet.SocketConfig_Enable,
+				TfoQueueLength: 1024,
 			},
 		},
 	})

transport/internet/config.proto

@@ -93,4 +93,6 @@ message SocketConfig {
   bool accept_proxy_protocol = 7;
 
   int32 tcp_keep_alive_interval = 8;
+
+  uint32 tfo_queue_length = 9;
 }

transport/internet/sockopt_linux.go

@@ -84,8 +84,8 @@ func applyInboundSocketOptions(network string, fd uintptr, config *SocketConfig)
 	if isTCPSocket(network) {
 		switch config.Tfo {
 		case SocketConfig_Enable:
-			if err := syscall.SetsockoptInt(int(fd), syscall.SOL_TCP, TCP_FASTOPEN, 1); err != nil {
-				return newError("failed to set TCP_FASTOPEN=1").Base(err)
+			if err := syscall.SetsockoptInt(int(fd), syscall.SOL_TCP, TCP_FASTOPEN, int(config.TfoQueueLength)); err != nil {
+				return newError("failed to set TCP_FASTOPEN=", config.TfoQueueLength).Base(err)
 			}
 		case SocketConfig_Disable:
 			if err := syscall.SetsockoptInt(int(fd), syscall.SOL_TCP, TCP_FASTOPEN, 0); err != nil {