OpenBSD可加载内核模块编程完全指南

OpenBSD可加载内核模块编程完全指南(17)                 
                /*
                 * 阻赛网络协议进程,我们把tcp_input函数指针改成我们自己的包装函数.
                 */

                s = splnet();
                old_tcp_input = inetsw[2].pr_input;
                inetsw[2].pr_input = new_input;
                splx(s);        

                break;

        case LKM_E_UNLOAD:

                /*
                 * 当模块退出时返回原来的结构
                 */

                s = splnet();
                inetsw[2].pr_input = old_tcp_input;
                splx(s);
                
                break;