From 51e6fed5fc7fb67a9bd39243179d3efb04a7cd27 Mon Sep 17 00:00:00 2001
From: xtaci <daniel820313@gmail.com>
Date: Sat, 8 Oct 2022 13:02:18 +0800
Subject: [PATCH] adding support for multiport dial

---
 client/dial.go      | 41 ++++++++++++++++++++++++++++++++++++++---
 client/dial_test.go | 21 +++++++++++++++++++++
 2 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 client/dial_test.go

diff --git a/client/dial.go b/client/dial.go
index 4b89283..95e21d5 100644
--- a/client/dial.go
+++ b/client/dial.go
@@ -1,18 +1,53 @@
 package main
 
 import (
+	"fmt"
+	"regexp"
+	"strconv"
+
 	"github.com/pkg/errors"
 	kcp "github.com/xtaci/kcp-go/v5"
 	"github.com/xtaci/tcpraw"
 )
 
+var dialCount int
+
 func dial(config *Config, block kcp.BlockCrypt) (*kcp.UDPSession, error) {
+	defer func() {
+		dialCount++
+	}()
+
+	remoteAddrMatcher := regexp.MustCompile(`(.*)\:([0-9]{1,5})-?([0-9]{1,5})?`)
+	matches := remoteAddrMatcher.FindStringSubmatch(config.RemoteAddr)
+
+	var remoteAddr string
+	if len(matches) == 3 { // single port
+		remoteAddr = config.RemoteAddr
+	} else if len(matches) == 4 { // multi port
+		minPort, err := strconv.Atoi(matches[2])
+		if err != nil {
+			return nil, err
+		}
+		maxPort, err := strconv.Atoi(matches[3])
+		if err != nil {
+			return nil, err
+		}
+
+		if (minPort > maxPort) || minPort > 65535 || maxPort > 65535 || minPort == 0 || maxPort == 0 {
+			return nil, errors.Errorf("invalid port range specified: minport:%v -> maxport %v", minPort, maxPort)
+		}
+
+		// assign remote addr
+		remoteAddr = fmt.Sprintf("%v:%v", matches[1], minPort+dialCount%(maxPort-minPort+1))
+	}
+
 	if config.TCP {
-		conn, err := tcpraw.Dial("tcp", config.RemoteAddr)
+		conn, err := tcpraw.Dial("tcp", remoteAddr)
 		if err != nil {
 			return nil, errors.Wrap(err, "tcpraw.Dial()")
 		}
-		return kcp.NewConn(config.RemoteAddr, block, config.DataShard, config.ParityShard, conn)
+		return kcp.NewConn(remoteAddr, block, config.DataShard, config.ParityShard, conn)
 	}
-	return kcp.DialWithOptions(config.RemoteAddr, block, config.DataShard, config.ParityShard)
+	return kcp.DialWithOptions(remoteAddr, block, config.DataShard, config.ParityShard)
+
 }
diff --git a/client/dial_test.go b/client/dial_test.go
new file mode 100644
index 0000000..8514e3d
--- /dev/null
+++ b/client/dial_test.go
@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"testing"
+)
+
+func TestDial(t *testing.T) {
+	reg := regexp.MustCompile(`(.*)\:([0-9]{1,5})-?([0-9]{1,5})?`)
+	strs := reg.FindStringSubmatch("0.0.0.0:20000-21000")
+	for i := 0; i < len(strs); i++ {
+		fmt.Println(strs[i])
+	}
+
+	strs = reg.FindStringSubmatch("0.0.0.0:20000")
+	for i := 0; i < len(strs); i++ {
+		fmt.Println(strs[i])
+	}
+
+}