add kcp dialer

pkg/dialer/kcp/dialer.go

@@ -0,0 +1,183 @@
+package kcp
+
+import (
+	"context"
+	"errors"
+	"net"
+	"sync"
+	"time"
+
+	kcp_util "github.com/go-gost/gost/pkg/common/util/kcp"
+	"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"
+	"github.com/xtaci/kcp-go/v5"
+	"github.com/xtaci/smux"
+	"github.com/xtaci/tcpraw"
+)
+
+func init() {
+	registry.RegisterDialer("kcp", NewDialer)
+}
+
+type kcpDialer struct {
+	sessions     map[string]*muxSession
+	sessionMutex sync.Mutex
+	logger       logger.Logger
+	md           metadata
+}
+
+func NewDialer(opts ...dialer.Option) dialer.Dialer {
+	options := &dialer.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &kcpDialer{
+		sessions: make(map[string]*muxSession),
+		logger:   options.Logger,
+	}
+}
+
+func (d *kcpDialer) Init(md md.Metadata) (err error) {
+	if err = d.parseMetadata(md); err != nil {
+		return
+	}
+
+	d.md.config.Init()
+
+	return nil
+}
+
+// IsMultiplex implements dialer.Multiplexer interface.
+func (d *kcpDialer) IsMultiplex() bool {
+	return true
+}
+
+func (d *kcpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (conn net.Conn, err error) {
+	var options dialer.DialOptions
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	d.sessionMutex.Lock()
+	defer d.sessionMutex.Unlock()
+
+	session, ok := d.sessions[addr]
+	if session != nil && session.IsClosed() {
+		delete(d.sessions, addr) // session is dead
+		ok = false
+	}
+	if !ok {
+		raddr, err := net.ResolveUDPAddr("udp", addr)
+		if err != nil {
+			return nil, err
+		}
+
+		if d.md.config.TCP {
+			pc, err := tcpraw.Dial("tcp", addr)
+			if err != nil {
+				return nil, err
+			}
+			conn = &fakeTCPConn{
+				raddr:      raddr,
+				PacketConn: pc,
+			}
+		} else {
+			conn, err = net.ListenUDP("udp", nil)
+			if err != nil {
+				return nil, err
+			}
+		}
+		session = &muxSession{conn: conn}
+		d.sessions[addr] = session
+	}
+
+	return session.conn, err
+}
+
+// Handshake implements dialer.Handshaker
+func (d *kcpDialer) Handshake(ctx context.Context, conn net.Conn, options ...dialer.HandshakeOption) (net.Conn, error) {
+	opts := &dialer.HandshakeOptions{}
+	for _, option := range options {
+		option(opts)
+	}
+	config := d.md.config
+
+	d.sessionMutex.Lock()
+	defer d.sessionMutex.Unlock()
+
+	if d.md.handshakeTimeout > 0 {
+		conn.SetDeadline(time.Now().Add(d.md.handshakeTimeout))
+		defer conn.SetDeadline(time.Time{})
+	}
+
+	session, ok := d.sessions[opts.Addr]
+	if !ok || session.session == nil {
+		s, err := d.initSession(opts.Addr, conn, config)
+		if err != nil {
+			d.logger.Error(err)
+			conn.Close()
+			delete(d.sessions, opts.Addr)
+			return nil, err
+		}
+		session = s
+		d.sessions[opts.Addr] = session
+	}
+	cc, err := session.GetConn()
+	if err != nil {
+		session.Close()
+		delete(d.sessions, opts.Addr)
+		return nil, err
+	}
+
+	return cc, nil
+}
+
+func (d *kcpDialer) initSession(addr string, conn net.Conn, config *kcp_util.Config) (*muxSession, error) {
+	pc, ok := conn.(net.PacketConn)
+	if !ok {
+		return nil, errors.New("wrong connection type")
+	}
+
+	kcpconn, err := kcp.NewConn(addr,
+		kcp_util.BlockCrypt(config.Key, config.Crypt, kcp_util.DefaultSalt),
+		config.DataShard, config.ParityShard, pc)
+	if err != nil {
+		return nil, err
+	}
+
+	kcpconn.SetStreamMode(true)
+	kcpconn.SetWriteDelay(false)
+	kcpconn.SetNoDelay(config.NoDelay, config.Interval, config.Resend, config.NoCongestion)
+	kcpconn.SetWindowSize(config.SndWnd, config.RcvWnd)
+	kcpconn.SetMtu(config.MTU)
+	kcpconn.SetACKNoDelay(config.AckNodelay)
+
+	if config.DSCP > 0 {
+		if err := kcpconn.SetDSCP(config.DSCP); err != nil {
+			d.logger.Warn("SetDSCP: ", err)
+		}
+	}
+	if err := kcpconn.SetReadBuffer(config.SockBuf); err != nil {
+		d.logger.Warn("SetReadBuffer: ", err)
+	}
+	if err := kcpconn.SetWriteBuffer(config.SockBuf); err != nil {
+		d.logger.Warn("SetWriteBuffer: ", err)
+	}
+
+	// stream multiplex
+	smuxConfig := smux.DefaultConfig()
+	smuxConfig.MaxReceiveBuffer = config.SockBuf
+	smuxConfig.KeepAliveInterval = time.Duration(config.KeepAlive) * time.Second
+	var cc net.Conn = kcpconn
+	if !config.NoComp {
+		cc = kcp_util.CompStreamConn(kcpconn)
+	}
+	session, err := smux.Client(cc, smuxConfig)
+	if err != nil {
+		return nil, err
+	}
+	return &muxSession{conn: conn, session: session}, nil
+}