make parsing generic

client/dial.go

@@ -2,11 +2,10 @@ package main
 
 import (
 	"fmt"
-	"regexp"
-	"strconv"
 
 	"github.com/pkg/errors"
 	kcp "github.com/xtaci/kcp-go/v5"
+	"github.com/xtaci/kcptun/generic"
 	"github.com/xtaci/tcpraw"
 )
 
@@ -17,30 +16,13 @@ func dial(config *Config, block kcp.BlockCrypt) (*kcp.UDPSession, error) {
 		dialCount++
 	}()
 
-	remoteAddrMatcher := regexp.MustCompile(`(.*)\:([0-9]{1,5})-?([0-9]{1,5})?`)
+	mp, err := generic.ParseMultiPort(config.RemoteAddr)
-	matches := remoteAddrMatcher.FindStringSubmatch(config.RemoteAddr)
+	if err != nil {
-
+		return nil, err
-	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], uint64(minPort)+dialCount%uint64(maxPort-minPort+1))
 	}
 
+	remoteAddr := fmt.Sprintf("%v:%v", mp.Host, uint64(mp.MinPort)+dialCount%uint64(mp.MaxPort-mp.MinPort+1))
+
 	if config.TCP {
 		conn, err := tcpraw.Dial("tcp", remoteAddr)
 		if err != nil {

generic/multiport.go

@@ -0,0 +1,50 @@
+package generic
+
+import (
+	"regexp"
+	"strconv"
+
+	"github.com/pkg/errors"
+)
+
+type MultiPort struct {
+	Host    string
+	MinPort uint64
+	MaxPort uint64
+}
+
+// Parse mulitport listener or dialer
+func ParseMultiPort(addr string) (*MultiPort, error) {
+	remoteAddrMatcher := regexp.MustCompile(`(.*)\:([0-9]{1,5})-?([0-9]{1,5})?`)
+	matches := remoteAddrMatcher.FindStringSubmatch(addr)
+
+	if len(matches) >= 3 {
+		var minPort, maxPort int
+		minPort, err := strconv.Atoi(matches[2])
+		if err != nil {
+			return nil, err
+		}
+		maxPort = minPort
+
+		// multiport assignment
+		if len(matches) >= 4 {
+			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)
+		}
+
+		mp := new(MultiPort)
+		mp.Host = matches[1]
+		mp.MinPort = uint64(minPort)
+		mp.MaxPort = uint64(maxPort)
+		return mp, nil
+	}
+
+	return nil, errors.Errorf("malformed address:%v", addr)
+
+}