Netstack is working

device/middle_device.go

@@ -19,15 +19,73 @@ type FilterRule struct {
 // MiddleDevice wraps a TUN device with packet filtering capabilities
 type MiddleDevice struct {
 	tun.Device
-	rules []FilterRule
-	mutex sync.RWMutex
+	rules    []FilterRule
+	mutex    sync.RWMutex
+	readCh   chan readResult
+	injectCh chan []byte
+	closed   chan struct{}
+}
+
+type readResult struct {
+	bufs   [][]byte
+	sizes  []int
+	offset int
+	n      int
+	err    error
 }
 
 // NewMiddleDevice creates a new filtered TUN device wrapper
 func NewMiddleDevice(device tun.Device) *MiddleDevice {
-	return &MiddleDevice{
-		Device: device,
-		rules:  make([]FilterRule, 0),
+	d := &MiddleDevice{
+		Device:   device,
+		rules:    make([]FilterRule, 0),
+		readCh:   make(chan readResult),
+		injectCh: make(chan []byte, 100),
+		closed:   make(chan struct{}),
+	}
+	go d.pump()
+	return d
+}
+
+func (d *MiddleDevice) pump() {
+	const defaultOffset = 16
+	batchSize := d.Device.BatchSize()
+
+	for {
+		select {
+		case <-d.closed:
+			return
+		default:
+		}
+
+		// Allocate buffers for reading
+		// We allocate new buffers for each read to avoid race conditions
+		// since we pass them to the channel
+		bufs := make([][]byte, batchSize)
+		sizes := make([]int, batchSize)
+		for i := range bufs {
+			bufs[i] = make([]byte, 2048) // Standard MTU + headroom
+		}
+
+		n, err := d.Device.Read(bufs, sizes, defaultOffset)
+
+		select {
+		case d.readCh <- readResult{bufs: bufs, sizes: sizes, offset: defaultOffset, n: n, err: err}:
+		case <-d.closed:
+			return
+		}
+
+		if err != nil {
+			return
+		}
+	}
+}
+
+// InjectOutbound injects a packet to be read by WireGuard (as if it came from TUN)
+func (d *MiddleDevice) InjectOutbound(packet []byte) {
+	select {
+	case d.injectCh <- packet:
+	case <-d.closed:
 	}
 }
 
@@ -54,6 +112,16 @@ func (d *MiddleDevice) RemoveRule(destIP netip.Addr) {
 	d.rules = newRules
 }
 
+// Close stops the device
+func (d *MiddleDevice) Close() error {
+	select {
+	case <-d.closed:
+	default:
+		close(d.closed)
+	}
+	return d.Device.Close()
+}
+
 // extractDestIP extracts destination IP from packet (fast path)
 func extractDestIP(packet []byte) (netip.Addr, bool) {
 	if len(packet) < 20 {
@@ -86,9 +154,49 @@ func extractDestIP(packet []byte) (netip.Addr, bool) {
 
 // Read intercepts packets going UP from the TUN device (towards WireGuard)
 func (d *MiddleDevice) Read(bufs [][]byte, sizes []int, offset int) (n int, err error) {
-	n, err = d.Device.Read(bufs, sizes, offset)
-	if err != nil || n == 0 {
-		return n, err
+	select {
+	case res := <-d.readCh:
+		if res.err != nil {
+			return 0, res.err
+		}
+
+		// Copy packets from result to provided buffers
+		count := 0
+		for i := 0; i < res.n && i < len(bufs); i++ {
+			// Handle offset mismatch if necessary
+			// We assume the pump used defaultOffset (16)
+			// If caller asks for different offset, we need to shift
+			src := res.bufs[i]
+			srcOffset := res.offset
+			srcSize := res.sizes[i]
+
+			// Calculate where the packet data starts and ends in src
+			pktData := src[srcOffset : srcOffset+srcSize]
+
+			// Ensure dest buffer is large enough
+			if len(bufs[i]) < offset+len(pktData) {
+				continue // Skip if buffer too small
+			}
+
+			copy(bufs[i][offset:], pktData)
+			sizes[i] = len(pktData)
+			count++
+		}
+		n = count
+
+	case pkt := <-d.injectCh:
+		if len(bufs) == 0 {
+			return 0, nil
+		}
+		if len(bufs[0]) < offset+len(pkt) {
+			return 0, nil // Buffer too small
+		}
+		copy(bufs[0][offset:], pkt)
+		sizes[0] = len(pkt)
+		n = 1
+
+	case <-d.closed:
+		return 0, nil // Device closed
 	}
 
 	d.mutex.RLock()
@@ -96,7 +204,7 @@ func (d *MiddleDevice) Read(bufs [][]byte, sizes []int, offset int) (n int, err
 	d.mutex.RUnlock()
 
 	if len(rules) == 0 {
-		return n, err
+		return n, nil
 	}
 
 	// Process packets and filter out handled ones

olm/olm.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"runtime"
+	"strings"
 	"time"
 
 	"github.com/fosrl/newt/bind"
@@ -509,6 +510,11 @@ func StartTunnel(config TunnelConfig) {
 		}
 
 		// TODO: seperate adding the callback to this so we can init it above with the interface
+		interfaceIP := wgData.TunnelIP
+		if strings.Contains(interfaceIP, "/") {
+			interfaceIP = strings.Split(interfaceIP, "/")[0]
+		}
+
 		peerMonitor = peermonitor.NewPeerMonitor(
 			func(siteID int, connected bool, rtt time.Duration) {
 				// Find the site config to get endpoint information
@@ -534,6 +540,8 @@ func StartTunnel(config TunnelConfig) {
 			olm,
 			dev,
 			config.Holepunch,
+			middleDev,
+			interfaceIP,
 		)
 
 		for i := range wgData.Sites {

peermonitor/peermonitor.go

@@ -3,14 +3,27 @@ package peermonitor
 import (
 	"context"
 	"fmt"
+	"net"
+	"net/netip"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/fosrl/newt/logger"
+	"github.com/fosrl/newt/util"
+	middleDevice "github.com/fosrl/olm/device"
 	"github.com/fosrl/olm/websocket"
 	"github.com/fosrl/olm/wgtester"
 	"golang.zx2c4.com/wireguard/device"
+	"gvisor.dev/gvisor/pkg/buffer"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/link/channel"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
+	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 )
 
 // PeerMonitorCallback is the function type for connection status change callbacks
@@ -39,11 +52,23 @@ type PeerMonitor struct {
 	wsClient          *websocket.Client
 	device            *device.Device
 	handleRelaySwitch bool // Whether to handle relay switching
+
+	// Netstack fields
+	middleDev   *middleDevice.MiddleDevice
+	localIP     string
+	stack       *stack.Stack
+	ep          *channel.Endpoint
+	activePorts map[uint16]bool
+	portsLock   sync.Mutex
+	nsCtx       context.Context
+	nsCancel    context.CancelFunc
+	nsWg        sync.WaitGroup
 }
 
 // NewPeerMonitor creates a new peer monitor with the given callback
-func NewPeerMonitor(callback PeerMonitorCallback, privateKey string, wsClient *websocket.Client, device *device.Device, handleRelaySwitch bool) *PeerMonitor {
-	return &PeerMonitor{
+func NewPeerMonitor(callback PeerMonitorCallback, privateKey string, wsClient *websocket.Client, device *device.Device, handleRelaySwitch bool, middleDev *middleDevice.MiddleDevice, localIP string) *PeerMonitor {
+	ctx, cancel := context.WithCancel(context.Background())
+	pm := &PeerMonitor{
 		monitors:          make(map[int]*wgtester.Client),
 		configs:           make(map[int]*WireGuardConfig),
 		callback:          callback,
@@ -54,7 +79,18 @@ func NewPeerMonitor(callback PeerMonitorCallback, privateKey string, wsClient *w
 		wsClient:          wsClient,
 		device:            device,
 		handleRelaySwitch: handleRelaySwitch,
+		middleDev:         middleDev,
+		localIP:           localIP,
+		activePorts:       make(map[uint16]bool),
+		nsCtx:             ctx,
+		nsCancel:          cancel,
 	}
+
+	if err := pm.initNetstack(); err != nil {
+		logger.Error("Failed to initialize netstack for peer monitor: %v", err)
+	}
+
+	return pm
 }
 
 // SetInterval changes how frequently peers are checked
@@ -101,35 +137,32 @@ func (pm *PeerMonitor) AddPeer(siteID int, endpoint string, wgConfig *WireGuardC
 	pm.mutex.Lock()
 	defer pm.mutex.Unlock()
 
-	// Check if we're already monitoring this peer
 	if _, exists := pm.monitors[siteID]; exists {
-		// Update the endpoint instead of creating a new monitor
-		pm.removePeerUnlocked(siteID)
+		return nil // Already monitoring
 	}
 
-	client, err := wgtester.NewClient(endpoint)
+	// Use our custom dialer that uses netstack
+	client, err := wgtester.NewClient(endpoint, pm.dial)
 	if err != nil {
 		return err
 	}
 
-	// Configure the client with our settings
 	client.SetPacketInterval(pm.interval)
 	client.SetTimeout(pm.timeout)
 	client.SetMaxAttempts(pm.maxAttempts)
 
-	// Store the client and config
 	pm.monitors[siteID] = client
 	pm.configs[siteID] = wgConfig
 
-	// If monitor is already running, start monitoring this peer
 	if pm.running {
-		siteIDCopy := siteID // Create a copy for the closure
-		err = client.StartMonitor(func(status wgtester.ConnectionStatus) {
-			pm.handleConnectionStatusChange(siteIDCopy, status)
-		})
+		if err := client.StartMonitor(func(status wgtester.ConnectionStatus) {
+			pm.handleConnectionStatusChange(siteID, status)
+		}); err != nil {
+			return err
+		}
 	}
 
-	return err
+	return nil
 }
 
 // removePeerUnlocked stops monitoring a peer and removes it from the monitor
@@ -329,3 +362,213 @@ func (pm *PeerMonitor) TestAllPeers() map[int]struct {
 
 	return results
 }
+
+// initNetstack initializes the gvisor netstack
+func (pm *PeerMonitor) initNetstack() error {
+	if pm.localIP == "" {
+		return fmt.Errorf("local IP not provided")
+	}
+
+	addr, err := netip.ParseAddr(pm.localIP)
+	if err != nil {
+		return fmt.Errorf("invalid local IP: %v", err)
+	}
+
+	// Create gvisor netstack
+	stackOpts := stack.Options{
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
+		HandleLocal:        true,
+	}
+
+	pm.ep = channel.New(256, 1420, "") // MTU 1420 (standard WG)
+	pm.stack = stack.New(stackOpts)
+
+	// Create NIC
+	if err := pm.stack.CreateNIC(1, pm.ep); err != nil {
+		return fmt.Errorf("failed to create NIC: %v", err)
+	}
+
+	// Add IP address
+	ipBytes := addr.As4()
+	protoAddr := tcpip.ProtocolAddress{
+		Protocol:          ipv4.ProtocolNumber,
+		AddressWithPrefix: tcpip.AddrFrom4(ipBytes).WithPrefix(),
+	}
+
+	if err := pm.stack.AddProtocolAddress(1, protoAddr, stack.AddressProperties{}); err != nil {
+		return fmt.Errorf("failed to add protocol address: %v", err)
+	}
+
+	// Add default route
+	pm.stack.AddRoute(tcpip.Route{
+		Destination: header.IPv4EmptySubnet,
+		NIC:         1,
+	})
+
+	// Register filter rule on MiddleDevice
+	// We want to intercept packets destined to our local IP
+	// But ONLY if they are for ports we are listening on
+	pm.middleDev.AddRule(addr, pm.handlePacket)
+
+	// Start packet sender (Stack -> WG)
+	pm.nsWg.Add(1)
+	go pm.runPacketSender()
+
+	return nil
+}
+
+// handlePacket is called by MiddleDevice when a packet arrives for our IP
+func (pm *PeerMonitor) handlePacket(packet []byte) bool {
+	// Check if it's UDP
+	proto, ok := util.GetProtocol(packet)
+	if !ok || proto != 17 { // UDP
+		return false
+	}
+
+	// Check destination port
+	port, ok := util.GetDestPort(packet)
+	if !ok {
+		return false
+	}
+
+	// Check if we are listening on this port
+	pm.portsLock.Lock()
+	active := pm.activePorts[uint16(port)]
+	pm.portsLock.Unlock()
+
+	if !active {
+		return false
+	}
+
+	// Inject into netstack
+	version := packet[0] >> 4
+	pkb := stack.NewPacketBuffer(stack.PacketBufferOptions{
+		Payload: buffer.MakeWithData(packet),
+	})
+
+	switch version {
+	case 4:
+		pm.ep.InjectInbound(ipv4.ProtocolNumber, pkb)
+	case 6:
+		pm.ep.InjectInbound(ipv6.ProtocolNumber, pkb)
+	default:
+		pkb.DecRef()
+		return false
+	}
+
+	pkb.DecRef()
+	return true // Handled
+}
+
+// runPacketSender reads packets from netstack and injects them into WireGuard
+func (pm *PeerMonitor) runPacketSender() {
+	defer pm.nsWg.Done()
+
+	for {
+		select {
+		case <-pm.nsCtx.Done():
+			return
+		default:
+		}
+
+		pkt := pm.ep.Read()
+		if pkt == nil {
+			time.Sleep(1 * time.Millisecond)
+			continue
+		}
+
+		// Extract packet data
+		slices := pkt.AsSlices()
+		if len(slices) > 0 {
+			var totalSize int
+			for _, slice := range slices {
+				totalSize += len(slice)
+			}
+
+			buf := make([]byte, totalSize)
+			pos := 0
+			for _, slice := range slices {
+				copy(buf[pos:], slice)
+				pos += len(slice)
+			}
+
+			// Inject into MiddleDevice (outbound to WG)
+			pm.middleDev.InjectOutbound(buf)
+		}
+
+		pkt.DecRef()
+	}
+}
+
+// dial creates a UDP connection using the netstack
+func (pm *PeerMonitor) dial(network, addr string) (net.Conn, error) {
+	if pm.stack == nil {
+		return nil, fmt.Errorf("netstack not initialized")
+	}
+
+	// Parse remote address
+	raddr, err := net.ResolveUDPAddr("udp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse local IP
+	localIP, err := netip.ParseAddr(pm.localIP)
+	if err != nil {
+		return nil, err
+	}
+	ipBytes := localIP.As4()
+
+	// Create UDP connection
+	// We bind to port 0 (ephemeral)
+	laddr := &tcpip.FullAddress{
+		NIC:  1,
+		Addr: tcpip.AddrFrom4(ipBytes),
+		Port: 0,
+	}
+
+	raddrTcpip := &tcpip.FullAddress{
+		NIC:  1,
+		Addr: tcpip.AddrFrom4([4]byte(raddr.IP.To4())),
+		Port: uint16(raddr.Port),
+	}
+
+	conn, err := gonet.DialUDP(pm.stack, laddr, raddrTcpip, ipv4.ProtocolNumber)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get local port
+	localAddr := conn.LocalAddr().(*net.UDPAddr)
+	port := uint16(localAddr.Port)
+
+	// Register port
+	pm.portsLock.Lock()
+	pm.activePorts[port] = true
+	pm.portsLock.Unlock()
+
+	// Wrap connection to cleanup port on close
+	return &trackedConn{
+		Conn: conn,
+		pm:   pm,
+		port: port,
+	}, nil
+}
+
+func (pm *PeerMonitor) removePort(port uint16) {
+	pm.portsLock.Lock()
+	delete(pm.activePorts, port)
+	pm.portsLock.Unlock()
+}
+
+type trackedConn struct {
+	net.Conn
+	pm   *PeerMonitor
+	port uint16
+}
+
+func (c *trackedConn) Close() error {
+	c.pm.removePort(c.port)
+	return c.Conn.Close()
+}

wgtester/wgtester.go

@@ -26,7 +26,7 @@ const (
 
 // Client handles checking connectivity to a server
 type Client struct {
-	conn           *net.UDPConn
+	conn           net.Conn
 	serverAddr     string
 	monitorRunning bool
 	monitorLock    sync.Mutex
@@ -35,8 +35,12 @@ type Client struct {
 	packetInterval time.Duration
 	timeout        time.Duration
 	maxAttempts    int
+	dialer         Dialer
 }
 
+// Dialer is a function that creates a connection
+type Dialer func(network, addr string) (net.Conn, error)
+
 // ConnectionStatus represents the current connection state
 type ConnectionStatus struct {
 	Connected bool
@@ -44,13 +48,14 @@ type ConnectionStatus struct {
 }
 
 // NewClient creates a new connection test client
-func NewClient(serverAddr string) (*Client, error) {
+func NewClient(serverAddr string, dialer Dialer) (*Client, error) {
 	return &Client{
 		serverAddr:     serverAddr,
 		shutdownCh:     make(chan struct{}),
 		packetInterval: 2 * time.Second,
 		timeout:        500 * time.Millisecond, // Timeout for individual packets
 		maxAttempts:    3,                      // Default max attempts
+		dialer:         dialer,
 	}, nil
 }
 
@@ -91,12 +96,14 @@ func (c *Client) ensureConnection() error {
 		return nil
 	}
 
-	serverAddr, err := net.ResolveUDPAddr("udp", c.serverAddr)
-	if err != nil {
-		return err
+	var err error
+	if c.dialer != nil {
+		c.conn, err = c.dialer("udp", c.serverAddr)
+	} else {
+		// Fallback to standard net.Dial
+		c.conn, err = net.Dial("udp", c.serverAddr)
 	}
 
-	c.conn, err = net.DialUDP("udp", nil, serverAddr)
 	if err != nil {
 		return err
 	}