add ssu connector

pkg/dialer/udp/conn.go

@@ -0,0 +1,17 @@
+package udp
+
+import "net"
+
+type conn struct {
+	*net.UDPConn
+}
+
+func (c *conn) WriteTo(b []byte, addr net.Addr) (int, error) {
+	return c.UDPConn.Write(b)
+}
+
+func (c *conn) ReadFrom(b []byte) (n int, addr net.Addr, err error) {
+	n, err = c.UDPConn.Read(b)
+	addr = c.RemoteAddr()
+	return
+}

pkg/dialer/udp/dialer.go

@@ -0,0 +1,54 @@
+package udp
+
+import (
+	"context"
+	"net"
+
+	"github.com/go-gost/gost/pkg/dialer"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegisterDialer("udp", NewDialer)
+}
+
+type udpDialer struct {
+	md     metadata
+	logger logger.Logger
+}
+
+func NewDialer(opts ...dialer.Option) dialer.Dialer {
+	options := &dialer.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &udpDialer{
+		logger: options.Logger,
+	}
+}
+
+func (d *udpDialer) Init(md md.Metadata) (err error) {
+	return d.parseMetadata(md)
+}
+
+func (d *udpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (net.Conn, error) {
+	taddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	c, err := net.DialUDP("udp", nil, taddr)
+	if err != nil {
+		return nil, err
+	}
+	return &conn{
+		UDPConn: c,
+	}, nil
+}
+
+func (d *udpDialer) parseMetadata(md md.Metadata) (err error) {
+	return
+}

pkg/dialer/udp/metadata.go

@@ -0,0 +1,15 @@
+package udp
+
+import "time"
+
+const (
+	dialTimeout = "dialTimeout"
+)
+
+const (
+	defaultDialTimeout = 5 * time.Second
+)
+
+type metadata struct {
+	dialTimeout time.Duration
+}