[client] Close the remote conn in proxy (#2626)

Port the conn close call to eBPF proxy

client/internal/wgproxy/ebpf/wrapper.go

@@ -0,0 +1,44 @@
+//go:build linux && !android
+
+package ebpf
+
+import (
+	"context"
+	"fmt"
+	"net"
+)
+
+// ProxyWrapper help to keep the remoteConn instance for net.Conn.Close function call
+type ProxyWrapper struct {
+	WgeBPFProxy *WGEBPFProxy
+
+	remoteConn net.Conn
+	cancel     context.CancelFunc // with thic cancel function, we stop remoteToLocal thread
+}
+
+func (e *ProxyWrapper) AddTurnConn(ctx context.Context, remoteConn net.Conn) (net.Addr, error) {
+	ctxConn, cancel := context.WithCancel(ctx)
+	addr, err := e.WgeBPFProxy.AddTurnConn(ctxConn, remoteConn)
+
+	if err != nil {
+		cancel()
+		return nil, fmt.Errorf("add turn conn: %w", err)
+	}
+	e.remoteConn = remoteConn
+	e.cancel = cancel
+	return addr, err
+}
+
+// CloseConn close the remoteConn and automatically remove the conn instance from the map
+func (e *ProxyWrapper) CloseConn() error {
+	if e.cancel == nil {
+		return fmt.Errorf("proxy not started")
+	}
+
+	e.cancel()
+
+	if err := e.remoteConn.Close(); err != nil {
+		return fmt.Errorf("failed to close remote conn: %w", err)
+	}
+	return nil
+}