Chore: move stack & device to core

core/stack/tcp.go

@@ -0,0 +1,91 @@
+package stack
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/xjasonlyu/tun2socks/common/adapter"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/waiter"
+)
+
+const (
+	// defaultWndSize if set to zero, the default
+	// receive window buffer size is used instead.
+	defaultWndSize = 0
+
+	// maxConnAttempts specifies the maximum number
+	// of in-flight tcp connection attempts.
+	maxConnAttempts = 2 << 10
+
+	// tcpKeepaliveIdle specifies the time a connection
+	// must remain idle before the first TCP keepalive
+	// packet is sent. Once this time is reached,
+	// tcpKeepaliveInterval option is used instead.
+	tcpKeepaliveIdle = 60 * time.Second
+
+	// tcpKeepaliveInterval specifies the interval
+	// time between sending TCP keepalive packets.
+	tcpKeepaliveInterval = 30 * time.Second
+)
+
+func withTCPHandler() Option {
+	return func(s *Stack) error {
+		tcpForwarder := tcp.NewForwarder(s.Stack, defaultWndSize, maxConnAttempts, func(r *tcp.ForwarderRequest) {
+			var wq waiter.Queue
+			id := r.ID()
+			ep, err := r.CreateEndpoint(&wq)
+			if err != nil {
+				// prevent potential half-open TCP connection leak.
+				r.Complete(true)
+				return
+			}
+			r.Complete(false)
+
+			setKeepalive(ep)
+
+			conn := &tcpConn{
+				Conn: gonet.NewTCPConn(&wq, ep),
+				metadata: &adapter.Metadata{
+					Net:     adapter.TCP,
+					SrcIP:   net.IP(id.RemoteAddress),
+					SrcPort: id.RemotePort,
+					DstIP:   net.IP(id.LocalAddress),
+					DstPort: id.LocalPort,
+				},
+			}
+
+			s.handler.Add(conn)
+		})
+		s.SetTransportProtocolHandler(tcp.ProtocolNumber, tcpForwarder.HandlePacket)
+		return nil
+	}
+}
+
+func setKeepalive(ep tcpip.Endpoint) error {
+	ep.SocketOptions().SetKeepAlive(true)
+
+	idle := tcpip.KeepaliveIdleOption(tcpKeepaliveIdle)
+	if err := ep.SetSockOpt(&idle); err != nil {
+		return fmt.Errorf("set keepalive idle: %s", err)
+	}
+
+	interval := tcpip.KeepaliveIntervalOption(tcpKeepaliveInterval)
+	if err := ep.SetSockOpt(&interval); err != nil {
+		return fmt.Errorf("set keepalive interval: %s", err)
+	}
+	return nil
+}
+
+type tcpConn struct {
+	net.Conn
+	metadata *adapter.Metadata
+}
+
+func (c *tcpConn) Metadata() *adapter.Metadata {
+	return c.metadata
+}