close #237, add linux bbr

examples/multi.server.toml

@@ -27,6 +27,8 @@ users = [ {user = "a684455c-b14f-11ea-bf0d-42010aaa0004"} , {user = "a684455c-b1
 
 # extra.tls_rejectUnknownSni = true # 这个开启了的话，防御效果更佳, 不过, 这要求你有真实证书
 
+#sockopt.bbr = true #用户空间的bbr拥塞控制, 仅限linux, see issue #237
+
 [[listen]]
 tag = "my_ws1"
 protocol = "vlesss"

netLayer/sockopt.go

@@ -9,6 +9,7 @@ import (
 type Sockopt struct {
 	TProxy bool   `toml:"tproxy"` //only linux
 	Somark int    `toml:"mark"`   //only linux
+	BBR    bool   `toml:"bbr"`    //only linux
 	Device string `toml:"device"`
 
 	//fastopen 不予支持, 因为自己客户端在重重网关之下，不可能让层层网关都支持tcp fast open；

netLayer/sockopt_linux.go

@@ -1,9 +1,10 @@
 package netLayer
 
 import (
+	"syscall"
+
 	"go.uber.org/zap"
 	"golang.org/x/sys/unix"
-	"syscall"
 
 	"github.com/e1732a364fed/v2ray_simple/utils"
 )
@@ -29,6 +30,14 @@ func SetSockOpt(fd int, sockopt *Sockopt, isudp bool, isipv6 bool) {
 		bindToDevice(fd, sockopt.Device)
 	}
 
+	if sockopt.BBR {
+		if err := syscall.SetsockoptString(fd, syscall.SOL_TCP, syscall.TCP_CONGESTION, "bbr"); err != nil {
+			if ce := utils.CanLogErr("bbr failed"); ce != nil {
+				ce.Write(zap.Error(err))
+			}
+		}
+	}
+
 }
 
 func bindToDevice(fd int, device string) {