在内核中使用线程与skb队列发送数据

在内核中我们发送数据一般使用dev_queue_xmit. 但是每次都需要通读等待返回, 通过线程的方式, 可以实现异步模式, 无需等待发送完成.可以大大加快发送速度.以下是示例代码:

static int xmit_thread_worker(void *arg);///////////////////////////////////////////////////////////////////////////////static struct task_struct*xmit_thread = NULL;// 等待线程启动与完成static struct completionstart_done;static struct completionend_done;// 线程状态static u32 thread_state = 0x0;// 终止线程标记static volatile u32xmit_stop = 0x0;// skb发送队列struct sk_buff_headpkt_xmit;///////////////////////////////////////////////////////////////////////////////int xmit_thread_init(void){int rc = 0x0;// 初始化队列与completionskb_queue_head_init( &pkt_xmit );init_completion( &start_done );init_completion( &end_done );// 创建线程xmit_thread = kthread_create( xmit_thread_worker, NULL, " ");if ( IS_ERR( xmit_thread ) ) {xmit_thread = NULL;pr_err( "kthread_create occur error./n" );rc = -1;}else {pr_emerg( "kthread_create success./n" ); // 唤醒线程wake_up_process( xmit_thread ); // 等待线程启动完成wait_for_completion( &start_done );pr_emerg( "xmit thread worker run success./n" );}return rc;}// skb入队列发送void xmit_enqueue( struct sk_buff *skb ){ // skb 入队列skb_queue_tail( &pkt_xmit, skb );if ( NULL != xmit_thread ){ // 唤醒线程wake_up_process( xmit_thread );}}// 销毁线程void xmit_thread_fini(void){struct sk_buff *skb = NULL;pr_emerg( "wait for xmit thread done/n" );if ( NULL == xmit_thread ){return ;}// 设置线程终止标记xmit_stop = 0x1; // 等待完成wait_for_completion( &end_done );// 释放队列中未发送skbdo {skb = __skb_dequeue( &pkt_xmit );if ( NULL != skb ) {kfree_skb( skb );}}while( NULL != skb );}static int xmit_thread_worker(void *arg){struct sk_buff *skb = NULL; // 通知启动完成complete( &start_done );while( 1 ) {thread_state = 0x0; // 调度schedule_timeout_interruptible(2);//__set_current_state(TASK_RUNNING);thread_state = 0x1;// 是否终止?if ( xmit_stop ) {pr_emerg( "%s end./n", __func__ );break;}do { // 取skb发送队列并发送skb = skb_dequeue( &pkt_xmit );if ( NULL != skb ) {dev_queue_xmit( skb );}// 是否终止?if ( xmit_stop ) {pr_emerg( "%s end./n", __func__ );goto _out;}}while( NULL != skb );};_out: // 通知线程终止complete( &end_done );return 0;}