From c21a7d8c4dc04ab7f6078f53b4a0b66e75a534ae Mon Sep 17 00:00:00 2001
From: nadoo <287492+nadoo@users.noreply.github.com>
Date: Sat, 18 Aug 2018 23:59:21 +0800
Subject: [PATCH] forawrder: change localip to interface

---
 README.md          |  2 +-
 proxy/direct.go    | 30 +++++++++++++++++++++++++-----
 proxy/forwarder.go |  6 +++---
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 48c2488..53bd636 100644
--- a/README.md
+++ b/README.md
@@ -217,7 +217,7 @@ Available forward strategies:
 
 Forwarder option scheme: FORWARD_URL#OPTIONS
   priority: set the priority of that forwarder, default:0
-  localip: set local ip address which will be used to connect remote forwarder
+  interface: set local interface or ip address used to connect remote forwarder
   -
   Examples:
     socks5://1.1.1.1:1080#priority=100
diff --git a/proxy/direct.go b/proxy/direct.go
index bf553eb..ed2e295 100644
--- a/proxy/direct.go
+++ b/proxy/direct.go
@@ -9,18 +9,38 @@ import (
 // Direct proxy
 type Direct struct {
 	*net.Dialer
+	addr net.Addr
 }
 
 // Default dialer
 var Default = &Direct{Dialer: &net.Dialer{}}
 
 // NewDirect returns a Direct dialer
-func NewDirect(localip string) *Direct {
-	d := &net.Dialer{LocalAddr: &net.TCPAddr{
-		IP:   net.ParseIP(localip),
+func NewDirect(intface string) *Direct {
+	d := &Direct{}
+	dialer := &net.Dialer{}
+
+	ip := net.ParseIP(intface)
+	if ip == nil {
+		iface, err := net.InterfaceByName(intface)
+		if err != nil {
+			return nil
+		}
+
+		addrs, err := iface.Addrs()
+		if err != nil {
+			d.addr = addrs[0]
+		}
+	}
+
+	d.addr = &net.TCPAddr{
+		IP:   ip,
 		Port: 0,
-	}}
-	return &Direct{Dialer: d}
+	}
+
+	dialer.LocalAddr = d.addr
+
+	return d
 }
 
 // Addr returns forwarder's address
diff --git a/proxy/forwarder.go b/proxy/forwarder.go
index 6249d65..5ec7b33 100644
--- a/proxy/forwarder.go
+++ b/proxy/forwarder.go
@@ -19,7 +19,7 @@ type Forwarder struct {
 	failures    uint32
 	MaxFailures uint32 //maxfailures to set to Disabled
 	latency     int64
-	localip     string // local ip address
+	intface     string // local interface or ip address
 }
 
 // ForwarderFromURL parses `forward=` command value and returns a new forwarder
@@ -31,7 +31,7 @@ func ForwarderFromURL(s string) (f *Forwarder, err error) {
 		err = f.parseOption(ss[1])
 	}
 
-	var d Dialer = NewDirect(f.localip)
+	var d Dialer = NewDirect(f.intface)
 	for _, url := range strings.Split(ss[0], ",") {
 		d, err = DialerFromURL(url, d)
 		if err != nil {
@@ -58,7 +58,7 @@ func (f *Forwarder) parseOption(option string) error {
 	}
 	f.Priority = int(priority)
 
-	f.localip = query.Get("localip")
+	f.intface = query.Get("interface")
 
 	return err
 }