Add `tcpMaxSeg` to `sockopt` (#2002)

infra/conf/transport_internet.go

@@ -617,6 +617,7 @@ type SocketConfig struct {
 	TCPKeepAliveIdle     int32       `json:"tcpKeepAliveIdle"`
 	TCPCongestion        string      `json:"tcpCongestion"`
 	TCPWindowClamp       int32       `json:"tcpWindowClamp"`
+	TCPMaxSeg	     int32	 `json:"tcpMaxSeg"`
 	TCPUserTimeout       int32       `json:"tcpUserTimeout"`
 	V6only               bool        `json:"v6only"`
 	Interface            string      `json:"interface"`
@@ -670,6 +671,7 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 		TcpKeepAliveIdle:     c.TCPKeepAliveIdle,
 		TcpCongestion:        c.TCPCongestion,
 		TcpWindowClamp:       c.TCPWindowClamp,
+		TcpMaxSeg:	      c.TCPMaxSeg,
 		TcpUserTimeout:       c.TCPUserTimeout,
 		V6Only:               c.V6only,
 		Interface:            c.Interface,

transport/internet/config.pb.go

@@ -429,6 +429,7 @@ type SocketConfig struct {
 	V6Only                     bool           `protobuf:"varint,14,opt,name=v6only,proto3" json:"v6only,omitempty"`
 	TcpWindowClamp             int32          `protobuf:"varint,15,opt,name=tcp_window_clamp,json=tcpWindowClamp,proto3" json:"tcp_window_clamp,omitempty"`
 	TcpUserTimeout             int32          `protobuf:"varint,16,opt,name=tcp_user_timeout,json=tcpUserTimeout,proto3" json:"tcp_user_timeout,omitempty"`
+	TcpMaxSeg                  int32          `protobuf:"varint,17,opt,name=tcp_max_seg,json=tcpMaxSeg,proto3" json:"tcp_max_seg,omitempty"`
 }
 
 func (x *SocketConfig) Reset() {
@@ -575,6 +576,13 @@ func (x *SocketConfig) GetTcpUserTimeout() int32 {
 	return 0
 }
 
+func (x *SocketConfig) GetTcpMaxSeg() int32 {
+	if x != nil {
+		return x.TcpMaxSeg
+	}
+	return 0
+}
+
 var File_transport_internet_config_proto protoreflect.FileDescriptor
 
 var file_transport_internet_config_proto_rawDesc = []byte{
@@ -627,7 +635,7 @@ var file_transport_internet_config_proto_rawDesc = []byte{
 	0x12, 0x30, 0x0a, 0x13, 0x74, 0x72, 0x61, 0x6e, 0x73, 0x70, 0x6f, 0x72, 0x74, 0x4c, 0x61, 0x79,
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@@ -671,7 +679,9 @@ var file_transport_internet_config_proto_rawDesc = []byte{
 	0x70, 0x57, 0x69, 0x6e, 0x64, 0x6f, 0x77, 0x43, 0x6c, 0x61, 0x6d, 0x70, 0x12, 0x28, 0x0a, 0x10,
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transport/internet/config.proto

@@ -106,4 +106,6 @@ message SocketConfig {
   int32 tcp_window_clamp = 15;
 
   int32 tcp_user_timeout = 16;
+
+  int32 tcp_max_seg = 17;
 }

transport/internet/sockopt_linux.go

@@ -94,6 +94,13 @@ func applyOutboundSocketOptions(network string, address string, fd uintptr, conf
 				return newError("failed to set TCP_USER_TIMEOUT", err)
 			}
 		}
+
+		if config.TcpMaxSeg > 0 {
+			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, unix.TCP_MAXSEG, int(config.TcpMaxSeg)); err != nil {
+				return newError("failed to set TCP_MAXSEG", err)
+			}
+		}
+
 	}
 
 	if config.Tproxy.IsEnabled() {
@@ -156,6 +163,12 @@ func applyInboundSocketOptions(network string, fd uintptr, config *SocketConfig)
 				return newError("failed to set TCP_USER_TIMEOUT", err)
 			}
 		}
+
+		if config.TcpMaxSeg > 0 {
+			if err := syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, unix.TCP_MAXSEG, int(config.TcpMaxSeg)); err != nil {
+				return newError("failed to set TCP_MAXSEG", err)
+			}
+		}
 	}
 
 	if config.Tproxy.IsEnabled() {