Using 2 nics not working

netstack2/handlers.go

@@ -0,0 +1,301 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2025 WireGuard LLC. All Rights Reserved.
+ */
+
+package netstack2
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/fosrl/newt/logger"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
+	"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
+
+	// tcpKeepaliveCount is the maximum number of
+	// TCP keep-alive probes to send before giving up
+	// and killing the connection if no response is
+	// obtained from the other end.
+	tcpKeepaliveCount = 9
+
+	// 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
+
+	// tcpConnectTimeout is the default timeout for TCP handshakes.
+	tcpConnectTimeout = 5 * time.Second
+
+	// tcpWaitTimeout implements a TCP half-close timeout.
+	tcpWaitTimeout = 60 * time.Second
+
+	// udpSessionTimeout is the default timeout for UDP sessions.
+	udpSessionTimeout = 60 * time.Second
+
+	// Buffer size for copying data
+	bufferSize = 32 * 1024
+)
+
+// TCPHandler handles TCP connections from netstack
+type TCPHandler struct {
+	stack *stack.Stack
+}
+
+// UDPHandler handles UDP connections from netstack
+type UDPHandler struct {
+	stack *stack.Stack
+}
+
+// NewTCPHandler creates a new TCP handler
+func NewTCPHandler(s *stack.Stack) *TCPHandler {
+	return &TCPHandler{stack: s}
+}
+
+// NewUDPHandler creates a new UDP handler
+func NewUDPHandler(s *stack.Stack) *UDPHandler {
+	return &UDPHandler{stack: s}
+}
+
+// InstallTCPHandler installs the TCP forwarder on the stack
+func (h *TCPHandler) InstallTCPHandler() error {
+	tcpForwarder := tcp.NewForwarder(h.stack, defaultWndSize, maxConnAttempts, func(r *tcp.ForwarderRequest) {
+		var (
+			wq  waiter.Queue
+			ep  tcpip.Endpoint
+			err tcpip.Error
+			id  = r.ID()
+		)
+
+		// Perform a TCP three-way handshake
+		ep, err = r.CreateEndpoint(&wq)
+		if err != nil {
+			// RST: prevent potential half-open TCP connection leak
+			r.Complete(true)
+			return
+		}
+		defer r.Complete(false)
+
+		// Set socket options
+		setTCPSocketOptions(h.stack, ep)
+
+		// Create TCP connection from netstack endpoint
+		netstackConn := gonet.NewTCPConn(&wq, ep)
+
+		// Handle the connection in a goroutine
+		go h.handleTCPConn(netstackConn, id)
+	})
+
+	h.stack.SetTransportProtocolHandler(tcp.ProtocolNumber, tcpForwarder.HandlePacket)
+	return nil
+}
+
+// handleTCPConn handles a TCP connection by proxying it to the actual target
+func (h *TCPHandler) handleTCPConn(netstackConn *gonet.TCPConn, id stack.TransportEndpointID) {
+	defer netstackConn.Close()
+
+	// Extract source and target address from the connection ID
+	srcIP := id.RemoteAddress.String()
+	srcPort := id.RemotePort
+	dstIP := id.LocalAddress.String()
+	dstPort := id.LocalPort
+
+	logger.Info("TCP Forwarder: Handling connection %s:%d -> %s:%d", srcIP, srcPort, dstIP, dstPort)
+
+	targetAddr := fmt.Sprintf("%s:%d", dstIP, dstPort)
+
+	// Create context with timeout for connection establishment
+	ctx, cancel := context.WithTimeout(context.Background(), tcpConnectTimeout)
+	defer cancel()
+
+	// Dial the actual target using standard net package
+	var d net.Dialer
+	targetConn, err := d.DialContext(ctx, "tcp", targetAddr)
+	if err != nil {
+		logger.Info("TCP Forwarder: Failed to connect to %s: %v", targetAddr, err)
+		// Connection failed, netstack will handle RST
+		return
+	}
+	defer targetConn.Close()
+
+	logger.Info("TCP Forwarder: Successfully connected to %s, starting bidirectional copy", targetAddr)
+
+	// Bidirectional copy between netstack and target
+	pipeTCP(netstackConn, targetConn)
+}
+
+// pipeTCP copies data bidirectionally between two connections
+func pipeTCP(origin, remote net.Conn) {
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+
+	go unidirectionalStreamTCP(remote, origin, "origin->remote", &wg)
+	go unidirectionalStreamTCP(origin, remote, "remote->origin", &wg)
+
+	wg.Wait()
+}
+
+// unidirectionalStreamTCP copies data in one direction
+func unidirectionalStreamTCP(dst, src net.Conn, dir string, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	buf := make([]byte, bufferSize)
+	_, _ = io.CopyBuffer(dst, src, buf)
+
+	// Do the upload/download side TCP half-close
+	if cr, ok := src.(interface{ CloseRead() error }); ok {
+		cr.CloseRead()
+	}
+	if cw, ok := dst.(interface{ CloseWrite() error }); ok {
+		cw.CloseWrite()
+	}
+
+	// Set TCP half-close timeout
+	dst.SetReadDeadline(time.Now().Add(tcpWaitTimeout))
+}
+
+// setTCPSocketOptions sets TCP socket options for better performance
+func setTCPSocketOptions(s *stack.Stack, ep tcpip.Endpoint) {
+	// TCP keepalive options
+	ep.SocketOptions().SetKeepAlive(true)
+
+	idle := tcpip.KeepaliveIdleOption(tcpKeepaliveIdle)
+	ep.SetSockOpt(&idle)
+
+	interval := tcpip.KeepaliveIntervalOption(tcpKeepaliveInterval)
+	ep.SetSockOpt(&interval)
+
+	ep.SetSockOptInt(tcpip.KeepaliveCountOption, tcpKeepaliveCount)
+
+	// TCP send/recv buffer size
+	var ss tcpip.TCPSendBufferSizeRangeOption
+	if err := s.TransportProtocolOption(tcp.ProtocolNumber, &ss); err == nil {
+		ep.SocketOptions().SetSendBufferSize(int64(ss.Default), false)
+	}
+
+	var rs tcpip.TCPReceiveBufferSizeRangeOption
+	if err := s.TransportProtocolOption(tcp.ProtocolNumber, &rs); err == nil {
+		ep.SocketOptions().SetReceiveBufferSize(int64(rs.Default), false)
+	}
+}
+
+// InstallUDPHandler installs the UDP forwarder on the stack
+func (h *UDPHandler) InstallUDPHandler() error {
+	udpForwarder := udp.NewForwarder(h.stack, func(r *udp.ForwarderRequest) {
+		var (
+			wq waiter.Queue
+			id = r.ID()
+		)
+
+		ep, err := r.CreateEndpoint(&wq)
+		if err != nil {
+			return
+		}
+
+		// Create UDP connection from netstack endpoint
+		netstackConn := gonet.NewUDPConn(&wq, ep)
+
+		// Handle the connection in a goroutine
+		go h.handleUDPConn(netstackConn, id)
+	})
+
+	h.stack.SetTransportProtocolHandler(udp.ProtocolNumber, udpForwarder.HandlePacket)
+	return nil
+}
+
+// handleUDPConn handles a UDP connection by proxying it to the actual target
+func (h *UDPHandler) handleUDPConn(netstackConn *gonet.UDPConn, id stack.TransportEndpointID) {
+	defer netstackConn.Close()
+
+	// Extract source and target address from the connection ID
+	srcIP := id.RemoteAddress.String()
+	srcPort := id.RemotePort
+	dstIP := id.LocalAddress.String()
+	dstPort := id.LocalPort
+
+	logger.Info("UDP Forwarder: Handling connection %s:%d -> %s:%d", srcIP, srcPort, dstIP, dstPort)
+
+	targetAddr := fmt.Sprintf("%s:%d", dstIP, dstPort)
+
+	// Resolve target address
+	remoteUDPAddr, err := net.ResolveUDPAddr("udp", targetAddr)
+	if err != nil {
+		logger.Info("UDP Forwarder: Failed to resolve %s: %v", targetAddr, err)
+		return
+	}
+
+	// Create UDP connection to target
+	targetConn, err := net.DialUDP("udp", nil, remoteUDPAddr)
+	if err != nil {
+		logger.Info("UDP Forwarder: Failed to dial %s: %v", targetAddr, err)
+		return
+	}
+	defer targetConn.Close()
+
+	logger.Info("UDP Forwarder: Successfully connected to %s, starting bidirectional copy", targetAddr)
+
+	// Bidirectional copy between netstack and target
+	pipeUDP(netstackConn, targetConn, remoteUDPAddr, udpSessionTimeout)
+}
+
+// pipeUDP copies UDP packets bidirectionally
+func pipeUDP(origin, remote net.PacketConn, to net.Addr, timeout time.Duration) {
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+
+	go unidirectionalPacketStream(remote, origin, to, "origin->remote", &wg, timeout)
+	go unidirectionalPacketStream(origin, remote, nil, "remote->origin", &wg, timeout)
+
+	wg.Wait()
+}
+
+// unidirectionalPacketStream copies packets in one direction
+func unidirectionalPacketStream(dst, src net.PacketConn, to net.Addr, dir string, wg *sync.WaitGroup, timeout time.Duration) {
+	defer wg.Done()
+	_ = copyPacketData(dst, src, to, timeout)
+}
+
+// copyPacketData copies UDP packet data with timeout
+func copyPacketData(dst, src net.PacketConn, to net.Addr, timeout time.Duration) error {
+	buf := make([]byte, 65535) // Max UDP packet size
+
+	for {
+		src.SetReadDeadline(time.Now().Add(timeout))
+		n, _, err := src.ReadFrom(buf)
+		if ne, ok := err.(net.Error); ok && ne.Timeout() {
+			return nil // ignore I/O timeout
+		} else if err == io.EOF {
+			return nil // ignore EOF
+		} else if err != nil {
+			return err
+		}
+
+		if _, err = dst.WriteTo(buf[:n], to); err != nil {
+			return err
+		}
+		dst.SetReadDeadline(time.Now().Add(timeout))
+	}
+}