add kcp dialer

pkg/dialer/kcp/metadata.go

@@ -0,0 +1,46 @@
+package kcp
+
+import (
+	"encoding/json"
+	"time"
+
+	kcp_util "github.com/go-gost/gost/pkg/common/util/kcp"
+	md "github.com/go-gost/gost/pkg/metadata"
+)
+
+type metadata struct {
+	handshakeTimeout time.Duration
+	config           *kcp_util.Config
+}
+
+func (d *kcpDialer) parseMetadata(md md.Metadata) (err error) {
+	const (
+		config           = "config"
+		handshakeTimeout = "handshakeTimeout"
+	)
+
+	if mm, _ := md.Get(config).(map[interface{}]interface{}); len(mm) > 0 {
+		m := make(map[string]interface{})
+		for k, v := range mm {
+			if sk, ok := k.(string); ok {
+				m[sk] = v
+			}
+		}
+		b, err := json.Marshal(m)
+		if err != nil {
+			return err
+		}
+		cfg := &kcp_util.Config{}
+		if err := json.Unmarshal(b, cfg); err != nil {
+			return err
+		}
+		d.md.config = cfg
+	}
+
+	if d.md.config == nil {
+		d.md.config = kcp_util.DefaultConfig
+	}
+
+	d.md.handshakeTimeout = md.GetDuration(handshakeTimeout)
+	return
+}