[client] fix/proxy close (#2873)

When the remote peer switches the Relay instance then must to close the proxy connection to the old instance.

It can cause issues when the remote peer switch connects to the Relay instance multiple times and then reconnects to an instance it had previously connected to.

client/iface/wgproxy/bind/proxy.go

@@ -2,6 +2,7 @@ package bind
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net"
 	"net/netip"
@@ -94,7 +95,10 @@ func (p *ProxyBind) close() error {
 
 	p.Bind.RemoveEndpoint(p.wgAddr)
 
-	return p.remoteConn.Close()
+	if rErr := p.remoteConn.Close(); rErr != nil && !errors.Is(rErr, net.ErrClosed) {
+		return rErr
+	}
+	return nil
 }
 
 func (p *ProxyBind) proxyToLocal(ctx context.Context) {

client/iface/wgproxy/ebpf/wrapper.go

@@ -77,7 +77,7 @@ func (e *ProxyWrapper) CloseConn() error {
 
 	e.cancel()
 
-	if err := e.remoteConn.Close(); err != nil {
+	if err := e.remoteConn.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
 		return fmt.Errorf("failed to close remote conn: %w", err)
 	}
 	return nil

client/iface/wgproxy/udp/proxy.go

@@ -116,7 +116,7 @@ func (p *WGUDPProxy) close() error {
 	p.cancel()
 
 	var result *multierror.Error
-	if err := p.remoteConn.Close(); err != nil {
+	if err := p.remoteConn.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
 		result = multierror.Append(result, fmt.Errorf("remote conn: %s", err))
 	}
 

client/internal/peer/conn.go

@@ -442,7 +442,7 @@ func (conn *Conn) relayConnectionIsReady(rci RelayConnInfo) {
 
 	if conn.iceP2PIsActive() {
 		conn.log.Debugf("do not switch to relay because current priority is: %v", conn.currentConnPriority)
-		conn.wgProxyRelay = wgProxy
+		conn.setRelayedProxy(wgProxy)
 		conn.statusRelay.Set(StatusConnected)
 		conn.updateRelayStatus(rci.relayedConn.RemoteAddr().String(), rci.rosenpassPubKey)
 		return
@@ -465,7 +465,7 @@ func (conn *Conn) relayConnectionIsReady(rci RelayConnInfo) {
 	wgConfigWorkaround()
 	conn.currentConnPriority = connPriorityRelay
 	conn.statusRelay.Set(StatusConnected)
-	conn.wgProxyRelay = wgProxy
+	conn.setRelayedProxy(wgProxy)
 	conn.updateRelayStatus(rci.relayedConn.RemoteAddr().String(), rci.rosenpassPubKey)
 	conn.log.Infof("start to communicate with peer via relay")
 	conn.doOnConnected(rci.rosenpassPubKey, rci.rosenpassAddr)
@@ -736,6 +736,15 @@ func (conn *Conn) logTraceConnState() {
 	}
 }
 
+func (conn *Conn) setRelayedProxy(proxy wgproxy.Proxy) {
+	if conn.wgProxyRelay != nil {
+		if err := conn.wgProxyRelay.CloseConn(); err != nil {
+			conn.log.Warnf("failed to close deprecated wg proxy conn: %v", err)
+		}
+	}
+	conn.wgProxyRelay = proxy
+}
+
 func isController(config ConnConfig) bool {
 	return config.LocalKey > config.Key
 }

relay/client/client.go

@@ -3,7 +3,6 @@ package client
 import (
 	"context"
 	"fmt"
-	"io"
 	"net"
 	"sync"
 	"time"
@@ -449,11 +448,11 @@ func (c *Client) writeTo(connReference *Conn, id string, dstID []byte, payload [
 	conn, ok := c.conns[id]
 	c.mu.Unlock()
 	if !ok {
-		return 0, io.EOF
+		return 0, net.ErrClosed
 	}
 
 	if conn.conn != connReference {
-		return 0, io.EOF
+		return 0, net.ErrClosed
 	}
 
 	// todo: use buffer pool instead of create new transport msg.
@@ -508,7 +507,7 @@ func (c *Client) closeConn(connReference *Conn, id string) error {
 
 	container, ok := c.conns[id]
 	if !ok {
-		return fmt.Errorf("connection already closed")
+		return net.ErrClosed
 	}
 
 	if container.conn != connReference {

relay/client/conn.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"io"
 	"net"
 	"time"
 )
@@ -40,7 +39,7 @@ func (c *Conn) Write(p []byte) (n int, err error) {
 func (c *Conn) Read(b []byte) (n int, err error) {
 	msg, ok := <-c.messageChan
 	if !ok {
-		return 0, io.EOF
+		return 0, net.ErrClosed
 	}
 
 	n = copy(b, msg.Payload)

relay/server/listener/ws/conn.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"net"
 	"sync"
 	"time"
@@ -100,15 +99,15 @@ func (c *Conn) isClosed() bool {
 
 func (c *Conn) ioErrHandling(err error) error {
 	if c.isClosed() {
-		return io.EOF
+		return net.ErrClosed
 	}
 
 	var wErr *websocket.CloseError
 	if !errors.As(err, &wErr) {
 		return err
 	}
 	if wErr.Code == websocket.StatusNormalClosure {
-		return io.EOF
+		return net.ErrClosed
 	}
 	return err
 }

relay/server/peer.go

@@ -2,7 +2,7 @@ package server
 
 import (
 	"context"
-	"io"
+	"errors"
 	"net"
 	"sync"
 	"time"
@@ -57,7 +57,7 @@ func (p *Peer) Work() {
 	for {
 		n, err := p.conn.Read(buf)
 		if err != nil {
-			if err != io.EOF {
+			if !errors.Is(err, net.ErrClosed) {
 				p.log.Errorf("failed to read message: %s", err)
 			}
 			return