close #141, 支持sendThrough配置

examples/multi.client.toml

@@ -75,6 +75,7 @@ insecure = true
 utls = true
 advancedLayer = "ws"
 path = "/ohmygod_verysimple_is_very_simple" 
+#sendThrough = "63.77.15.11"	# dial可以设置 sendThrough为自己的某一个ip地址，来达到选择特定的ip来拨号的目的。常用与 服务器有ipv4和ipv6双栈，而因为某些原因需要单独使用 v4 或者v6  的情况。 （这里给出的示例ip是假的，请改为你自己的ip地址）
 
 
 [[dial]]

main.go

@@ -1092,7 +1092,7 @@ func dialClient(iics incomingInserverConnState, targetAddr netLayer.Addr,
 			}
 		}
 
-		clientConn, err = realTargetAddr.Dial(client.GetSockopt())
+		clientConn, err = realTargetAddr.Dial(client.GetSockopt(), client.LocalAddr())
 
 		if err != nil {
 			if err == netLayer.ErrMachineCantConnectToIpv6 {

netLayer/addr.go

@@ -633,3 +633,22 @@ func V2rayGetAddrFrom(buf utils.ByteReader) (addr Addr, err error) {
 
 	return
 }
+
+func StrToNetAddr(network, s string) (net.Addr, error) {
+	if network == "" {
+		network = "tcp"
+	}
+	realNet := StrToTransportProtocol(network)
+	switch realNet {
+	case IP:
+		return net.ResolveIPAddr(network, s)
+	case TCP:
+		return net.ResolveTCPAddr(network, s)
+	case UDP:
+		return net.ResolveUDPAddr(network, s)
+	case UNIX:
+		return net.ResolveUnixAddr(network, s)
+	default:
+		return nil, utils.ErrWrongParameter
+	}
+}

netLayer/const.go

@@ -6,6 +6,7 @@ const (
 	TCP uint16 = 1 << iota
 	UDP
 	UNIX //unix domain socket
+	IP
 	Raw_socket
 	KCP
 	Quic //quic是一个横跨多个层的协议，这里也算一个，毕竟与kcp类似

netLayer/dial.go

@@ -21,7 +21,7 @@ const (
 //Dial 可以拨号tcp、udp、unix domain socket、tls 这几种协议。
 //如果不是这几种之一，则会尝试查询 CustomDialerMap 找出匹配的函数进行拨号。
 //如果找不到，则会使用net包的方法进行拨号（其会返回错误）。
-func (a *Addr) Dial(sockopt *Sockopt) (net.Conn, error) {
+func (a *Addr) Dial(sockopt *Sockopt, localAddr net.Addr) (net.Conn, error) {
 	var istls bool
 	var resultConn net.Conn
 	var err error
@@ -38,13 +38,13 @@ func (a *Addr) Dial(sockopt *Sockopt) (net.Conn, error) {
 	case "udp", "udp4", "udp6":
 		ua := a.ToUDPAddr()
 
-		if sockopt == nil {
+		if sockopt == nil && localAddr == nil {
 
 			return DialUDP(ua)
 		} else {
 
 			var c net.Conn
-			c, err = a.DialWithOpt(sockopt)
+			c, err = a.DialWithOpt(sockopt, localAddr)
 			if err == nil {
 				uc := c.(*net.UDPConn)
 				return NewUDPConn(ua, uc, true), nil
@@ -71,14 +71,14 @@ tcp:
 
 		var tcpConn *net.TCPConn
 
-		if sockopt == nil {
+		if sockopt == nil && localAddr == nil {
 			tcpConn, err = net.DialTCP("tcp", nil, &net.TCPAddr{
 				IP:   a.IP,
 				Port: a.Port,
 			})
 		} else {
 			var c net.Conn
-			c, err = a.DialWithOpt(sockopt)
+			c, err = a.DialWithOpt(sockopt, localAddr)
 			if err == nil {
 				tcpConn = c.(*net.TCPConn)
 			}
@@ -98,21 +98,21 @@ defaultPart:
 	if istls {
 		//若tls到达了这里，则说明a的ip没有给出，而只给出了域名，所以上面tcp部分没有直接拨号
 
-		if sockopt == nil {
+		if sockopt == nil && localAddr == nil {
 			resultConn, err = net.DialTimeout("tcp", a.String(), defaultDialTimeout)
 
 		} else {
 			newA := *a
 			newA.Network = "tcp"
-			resultConn, err = newA.DialWithOpt(sockopt)
+			resultConn, err = newA.DialWithOpt(sockopt, localAddr)
 		}
 
 	} else {
 		//一般情况下，unix domain socket 会到达这里，其他情况则都被前面代码捕获到了
 		if sockopt == nil {
 			resultConn, err = net.DialTimeout(a.Network, a.String(), defaultDialTimeout)
 		} else {
-			resultConn, err = a.DialWithOpt(sockopt)
+			resultConn, err = a.DialWithOpt(sockopt, localAddr)
 		}
 
 	}
@@ -136,16 +136,23 @@ dialedPart:
 
 }
 
-func (a Addr) DialWithOpt(sockopt *Sockopt) (net.Conn, error) {
+//比Dial更低级的方法，专用于使用sockopt的情况。
+//这里调用者要保证sockopt不为nil。a的Network只能为golang支持的那几种。
+func (a Addr) DialWithOpt(sockopt *Sockopt, localAddr net.Addr) (net.Conn, error) {
 
 	dialer := &net.Dialer{
 		Timeout: defaultDialTimeout,
 	}
-	dialer.Control = func(network, address string, c syscall.RawConn) error {
-		return c.Control(func(fd uintptr) {
-			SetSockOpt(int(fd), sockopt, a.IsUDP(), a.IsIpv6())
+	if localAddr != nil {
+		dialer.LocalAddr = localAddr
+	}
+	if sockopt != nil {
+		dialer.Control = func(network, address string, c syscall.RawConn) error {
+			return c.Control(func(fd uintptr) {
+				SetSockOpt(int(fd), sockopt, a.IsUDP(), a.IsIpv6())
 
-		})
+			})
+		}
 	}
 
 	return dialer.Dial(a.Network, a.String())

netLayer/dns.go

@@ -186,7 +186,7 @@ func DialDnsAddr(addr *Addr) (conn net.Conn, err error) {
 	if addr.IsUDP() {
 		conn, err = net.DialUDP("udp", nil, addr.ToUDPAddr())
 	} else {
-		conn, err = addr.Dial(nil)
+		conn, err = addr.Dial(nil, nil)
 
 	}
 	//todo: 以后支持DoH的话，要分离出https这个Network然后单独使用独特方法进行dial

proxy/base.go

@@ -3,6 +3,7 @@ package proxy
 import (
 	"crypto/tls"
 	"io"
+	"net"
 	"strings"
 	"sync"
 
@@ -86,6 +87,7 @@ type Base struct {
 	DialConf   *DialConf
 
 	Addr           string
+	LA             net.Addr //for client's LocalAddr
 	TLS            bool
 	Tag            string //可用于路由, 见 netLayer.route.go
 	TransportLayer string
@@ -122,6 +124,10 @@ func (b *Base) Network() string {
 	return b.TransportLayer
 }
 
+func (b *Base) LocalAddr() net.Addr {
+	return b.LA
+}
+
 func (b *Base) GetXver() int {
 	return b.Xver
 }

proxy/config_proxy.go

@@ -131,6 +131,9 @@ type ListenConf struct {
 //  CommonConf.Host , CommonConf.IP, CommonConf.Port  is the addr and port for dialing.
 type DialConf struct {
 	CommonConf
+
+	SendThrough string `toml:"sendThrough"` //可选，用于发送数据的 IP 地址
+
 	Utls bool `toml:"utls"` //是否使用 uTls 库 替换 go官方tls库
 
 	Mux bool `toml:"use_mux"` //是否使用内层mux。在某些支持mux命令的协议中（vless v1/trojan）, 开启此开关会让 dial 使用 内层mux。

proxy/creator.go

@@ -93,6 +93,16 @@ func newclient(creator ClientCreator, dc *DialConf, knownTls bool) (Client, erro
 		c.GetBase().TLS = true
 		e = prepareTLS_forClient(c, dc)
 	}
+	if dc.SendThrough != "" {
+		st, err := netLayer.StrToNetAddr(c.Network(), dc.SendThrough)
+		if err != nil {
+			return nil, utils.ErrInErr{ErrDesc: "parse sendthrough ip failed", ErrDetail: err}
+
+		} else {
+			c.GetBase().LA = st
+
+		}
+	}
 	return c, e
 
 }

proxy/direct.go

@@ -39,9 +39,9 @@ func (d *DirectClient) Handshake(underlay net.Conn, firstPayload []byte, target
 
 	if underlay == nil {
 		if d.Sockopt != nil {
-			result, err = target.DialWithOpt(d.Sockopt)
+			result, err = target.DialWithOpt(d.Sockopt, d.LA)
 		} else {
-			result, err = target.Dial(nil)
+			result, err = target.Dial(nil, d.LA)
 		}
 
 	} else {

proxy/proxy.go

@@ -60,6 +60,8 @@ type Client interface {
 	InnerMuxEstablished() bool
 	CloseInnerMuxSession()
 
+	LocalAddr() net.Addr //用于在拨号时选用一个特定的ip拨号。
+
 	sync.Locker //用于锁定 innerMux
 }