add tunnel handler and connector

connector/tunnel/metadata.go

@@ -0,0 +1,42 @@
+package tunnel
+
+import (
+	"errors"
+	"time"
+
+	mdata "github.com/go-gost/core/metadata"
+	mdutil "github.com/go-gost/core/metadata/util"
+	"github.com/go-gost/relay"
+	"github.com/google/uuid"
+)
+
+var (
+	ErrInvalidTunnelID = errors.New("tunnel: invalid tunnel ID")
+)
+
+type metadata struct {
+	connectTimeout time.Duration
+	tunnelID       relay.TunnelID
+}
+
+func (c *tunnelConnector) parseMetadata(md mdata.Metadata) (err error) {
+	const (
+		connectTimeout = "connectTimeout"
+		noDelay        = "nodelay"
+	)
+
+	c.md.connectTimeout = mdutil.GetDuration(md, connectTimeout)
+
+	if s := mdutil.GetString(md, "tunnelID", "tunnel.id"); s != "" {
+		uuid, err := uuid.Parse(s)
+		if err != nil {
+			return err
+		}
+		c.md.tunnelID = relay.NewTunnelID(uuid[:])
+	}
+
+	if c.md.tunnelID.IsZero() {
+		return ErrInvalidTunnelID
+	}
+	return
+}