add dtls tunnel

dialer/dtls/dialer.go

@@ -0,0 +1,65 @@
+package dtls
+
+import (
+	"context"
+	"crypto/tls"
+	"net"
+
+	"github.com/go-gost/core/dialer"
+	"github.com/go-gost/core/logger"
+	md "github.com/go-gost/core/metadata"
+	"github.com/go-gost/x/registry"
+	"github.com/pion/dtls/v2"
+)
+
+func init() {
+	registry.DialerRegistry().Register("dtls", NewDialer)
+}
+
+type dtlsDialer struct {
+	md      metadata
+	logger  logger.Logger
+	options dialer.Options
+}
+
+func NewDialer(opts ...dialer.Option) dialer.Dialer {
+	options := dialer.Options{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return &dtlsDialer{
+		logger:  options.Logger,
+		options: options,
+	}
+}
+
+func (d *dtlsDialer) Init(md md.Metadata) (err error) {
+	return d.parseMetadata(md)
+}
+
+func (d *dtlsDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (net.Conn, error) {
+	var options dialer.DialOptions
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	conn, err := options.NetDialer.Dial(ctx, "udp", addr)
+	if err != nil {
+		d.logger.Error(err)
+	}
+
+	tlsCfg := d.options.TLSConfig
+	if tlsCfg == nil {
+		tlsCfg = &tls.Config{}
+	}
+	config := dtls.Config{
+		Certificates:         tlsCfg.Certificates,
+		InsecureSkipVerify:   tlsCfg.InsecureSkipVerify,
+		ExtendedMasterSecret: dtls.RequireExtendedMasterSecret,
+		ServerName:           tlsCfg.ServerName,
+		RootCAs:              tlsCfg.RootCAs,
+	}
+
+	return dtls.ClientWithContext(ctx, conn, &config)
+}