添加readv功能;给出测试数据;修订代码,注释;

toml 新增 app.noreadv项，命令行参数新增 -readv

默认readv是打开状态，可以选择性关闭。

netLayer/relay.go

@@ -1,14 +1,161 @@
 package netLayer
 
 import (
+	"flag"
 	"io"
+	"log"
 	"net"
+	"reflect"
+	"runtime"
+	"syscall"
+
+	"github.com/hahahrfool/v2ray_simple/utils"
 )
 
+const SystemCanSplice = runtime.GOARCH != "wasm" && runtime.GOOS != "windows"
+
+var UseReadv bool
+
+func init() {
+	flag.BoolVar(&UseReadv, "readv", true, "toggle the use of 'readv' syscall")
+
+}
+
+//这里认为能 splice 或 sendfile的 都算
+func CanSplice(r interface{}) bool {
+
+	if _, ok := r.(*net.TCPConn); ok {
+		return true
+	} else if _, ok := r.(*net.UnixConn); ok {
+
+		return true
+	}
+	return false
+
+}
+
+// TryCopy 尝试 循环 从 readConn 读取数据并写入 writeConn, 直到错误发生。
+//会接连尝试 splice、循环readv 以及 原始Copy方法
+func TryCopy(writeConn io.Writer, readConn io.Reader) (allnum int64, err error) {
+	var mr utils.MultiReader
+	var buffers net.Buffers
+	var rawConn syscall.RawConn
+
+	if utils.CanLogDebug() {
+		log.Println("TryCopy", reflect.TypeOf(readConn), "->", reflect.TypeOf(writeConn))
+	}
+
+	if SystemCanSplice && CanSplice(readConn) && CanSplice(writeConn) {
+		if utils.CanLogDebug() {
+			log.Println("copying with splice")
+		}
+		goto copy
+	}
+	// 不全 支持splice的话，我们就考虑 read端 可 readv 的情况
+	// 连readv都不让 那就直接 经典拷贝
+	if !UseReadv {
+		goto classic
+	}
+
+	rawConn = GetRawConn(readConn)
+
+	if rawConn == nil {
+		goto classic
+	}
+
+	mr = utils.GetReadVReader()
+	if utils.CanLogDebug() {
+		log.Println("copying with readv")
+	}
+	for {
+		buffers, err = ReadFromMultiReader(rawConn, mr)
+		if err != nil {
+			return 0, err
+		}
+		num, err2 := buffers.WriteTo(writeConn)
+		allnum += num
+		if err2 != nil {
+			err = err2
+			return
+		}
+		ReleaseNetBuffers(buffers)
+	}
+classic:
+	if utils.CanLogDebug() {
+		log.Println("copying with classic method")
+	}
+copy:
+
+	//Copy内部实现 会自动进行splice, 若无splice实现则直接使用原始方法 “循环读取 并 写入”
+	return io.Copy(writeConn, readConn)
+}
+
+// 类似TryCopy，但是只会读写一次
+func TryCopyOnce(writeConn io.Writer, readConn io.Reader) (allnum int64, err error) {
+	var mr utils.MultiReader
+	var buffers net.Buffers
+	var rawConn syscall.RawConn
+
+	if utils.CanLogDebug() {
+		log.Println("TryCopy", reflect.TypeOf(readConn), "->", reflect.TypeOf(writeConn))
+	}
+
+	if SystemCanSplice && CanSplice(readConn) && CanSplice(writeConn) {
+		if utils.CanLogDebug() {
+			log.Println("copying with splice")
+		}
+		goto copy
+	}
+	// 不全 支持splice的话，我们就考虑 read端 可 readv 的情况
+	// 连readv都不让 那就直接 经典拷贝
+	if !UseReadv {
+		goto classic
+	}
+
+	rawConn = GetRawConn(readConn)
+
+	if rawConn == nil {
+		goto classic
+	}
+
+	mr = utils.GetReadVReader()
+	if utils.CanLogDebug() {
+		log.Println("copying with readv")
+	}
+
+	buffers, err = ReadFromMultiReader(rawConn, mr)
+	if err != nil {
+		return 0, err
+	}
+	allnum, err = buffers.WriteTo(writeConn)
+
+	ReleaseNetBuffers(buffers)
+	return
+
+classic:
+	if utils.CanLogDebug() {
+		log.Println("copying with classic method")
+	}
+copy:
+
+	//Copy内部实现 会自动进行splice, 若无splice实现则直接使用原始方法 “循环读取 并 写入”
+	return io.Copy(writeConn, readConn)
+}
+
+// 从conn1读取 写入到 conn2，并同时从 conn2读取写入conn1
 // 阻塞
-func RelayTCP(conn1, conn2 net.Conn) {
-	go io.Copy(conn2, conn1)
-	io.Copy(conn1, conn2)
+// 返回从 conn1读取 写入到 conn2的数据
+// UseReadv==true 时 内部使用 TryCopy 进行拷贝
+func Relay(conn1, conn2 io.ReadWriter) (int64, error) {
+
+	if UseReadv {
+		go TryCopy(conn1, conn2)
+		return TryCopy(conn2, conn1)
+
+	} else {
+		go io.Copy(conn1, conn2)
+		return io.Copy(conn2, conn1)
+	}
 }
 
 // 阻塞.