局域网环境tcp发送超时导致重启

发布于 2015-04-20 17:56:19 浏览：2227 订阅该版

环境：
rt-thread 1.0.1
lwip 1.4.0
mcu:stm32f103
网卡：enc28j60

设备与pc在同一局域网，pc为server,设备client. 设备向pc端发送tcp数据 。 发送使用select，有可用资源时再write数据
出现问题：： 每隔几分钟出现select超时，tcp write失败并关闭链接，多次后设备重启！！。。

分析： 
为什么会出现select超时以及发送失败？ 发送速度大概几k每秒。 若采用设备pc直连方式就没有频繁超时重启的问题。 
应用层是用的标准的发送流程，应该没有什么问题，是否是协议栈及lwip的性能稳定性问题？ 
或者能否有些调试的思路和方法
项目很急，万分感谢！！

串口log如下，可以看到超时及发送失败多次后设备重启了。。
insh>>send failed, close connect...
send failed, close connect...
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
select() timeout for writing
send() failed! sock_err=104send failed, close connect...
send failed, close connect...
enc28j60 clkrdy signal 1
enc28j60 clkrdy ok
Onevo TM->To enter the BOOT upgrade mode , press the 'Enter'  
time_S is 5 
waitting time end into app...

| /
- RT -     Thread Operating System
 / |      1.0.1 build Apr 17 2015
 2006 - 2011 Copyright by rt-thread team
TCP/IP initialized.
TCP/IP initialized!

设备端发送代码：
```int app_tcp_send(int sock, struct data_packet *wdata, uint32_t timeout_usec)
{
	struct timeval timeout;
	fd_set w_fd;
	int cnt;
	int ret = 0;
	int len;
	int wlen;	  
	if(sock < 0 || wdata == NULL) {
		syslog(WARN,"app_tcp_send() invalid para!
");
		return -1;
	}

len = DATA_HEAD_LEN+wdata->len;
	wdata->len = htons(wdata->len);
	
	timeout.tv_sec = timeout_usec/1000000;
	timeout.tv_usec = timeout_usec%1000000;
	
	FD_ZERO(&w_fd);				  //初始化 w_fd	为空
	FD_SET(sock,&w_fd);			  //把sock添加到 w_fd中去

cnt = select(sock+1,NULL,&w_fd,NULL,&timeout);
	
	if ( cnt < 0 ) {

syslog(WARN,"select() failed! sock_err=%d
",lwip_get_error(sock));
		rt_kprintf("select() failed! sock_err=%d
",lwip_get_error(sock));
		ret = -1;
	}
	else if ( cnt == 0 ){

syslog(WARN,"select() timeout for writing
");
		rt_kprintf("select() timeout for writing
");
		ret = 1;
	}
	else {
  
		wlen = writen(sock,(const uint8_t *)wdata,len);

if( wlen < 0) {

syslog(WARN,"send() failed! sock_err=%d",lwip_get_error(sock));
			rt_kprintf("send() failed! sock_err=%d",lwip_get_error(sock));
			ret = -1;

} else if( wlen == len) {

ret = 1;
//			syslog(INFO,"send ok! len=%d",len);

} else{

syslog(WARN,"send failed!send len =%d, data len =%d",wlen, len);
			rt_kprintf("send failed!send len =%d, data len =%d",wlen, len);
			ret = -1;
		}
		
	}

return ret;
	
}```