Question

我正在尝试使用德州仪器（TI）的助推器包cc3000发送数据。因此我在我的主板上实现了一个TCP服务器套接字。我可以成功接受挂起的连接，并在给定的套接字上发送和接收数据。在我的协议中，客户端负责在读取响应后关闭连接。但是在一些传输之后传输变得缓慢。如果我使用Wireshark检查WLAN流量，我发现套接字关闭过程有问题。我的客户端是基于java的程序。该板使用地址100，计算机在102下运行。

TCP流看起来如下：

 31 4.696711000    192.168.2.102         192.168.2.100         TCP      66     50721 > http-alt [SYN] Seq=0 Win=8192 Len=0 MSS=1460 WS=4 SACK_PERM=1
 32 4.700359000    192.168.2.100         192.168.2.102         TCP      58     http-alt > 50721 [SYN, ACK] Seq=0 Ack=1 Win=1460 Len=0 MSS=1460
 33 4.700394000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=1 Ack=1 Win=17520 Len=0
 34 4.700461000    192.168.2.102         192.168.2.100         HTTP     55     Continuation or non-HTTP traffic
 35 4.705454000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=1 Ack=2 Win=1460 Len=0
 36 4.705476000    192.168.2.102         192.168.2.100         TCP      57     [TCP segment of a reassembled PDU]
 37 4.709035000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=1 Ack=5 Win=1460 Len=0
 38 5.194961000    192.168.2.100         192.168.2.102         TCP      58     [TCP segment of a reassembled PDU]
 39 5.196220000    192.168.2.100         192.168.2.102         HTTP     154    Continuation or non-HTTP traffic
 40 5.196244000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=5 Ack=105 Win=17416 Len=0
 41 5.196286000    192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [FIN, ACK] Seq=5 Ack=105 Win=17416 Len=0
 42 5.202194000    192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [ACK] Seq=105 Ack=6 Win=1460 Len=0
138 24.245036000   192.168.2.100         192.168.2.102         TCP      54     http-alt > 50721 [FIN, ACK] Seq=105 Ack=6 Win=1460 Len=0
139 24.245060000   192.168.2.102         192.168.2.100         TCP      54     50721 > http-alt [ACK] Seq=6 Ack=106 Win=17416 Len=0

在大约10次传输后，我得到了FIN / ACK级联。上面的最后一个FIN / ACK是这个级联的一部分。看起来套接字没有完全关闭，HW模块现在开始关闭一行中的所有套接字。

    My Java - client does the following
    Socket b = new Socket("192.168.2.100",8080);
    OutputStream o = b.getOutputStream();
    o.write(10);
    o.write(0);
    o.write(0);
    o.write(0);
    o.flush();

    InputStream i = b.getInputStream();

    int id = i.read();
    int gId = i.read();

    int lengthA = i.read();
    int lengthB = i.read();
    int length = (lengthB<<8)|lengthA;
    if(length < 0|| length > 1000)
    {
        b.close();
        return;
    }

    System.out.println(new Date()+" GantryID: "+gId+" Package with id: "+id+" has length: "+length+" payload: ");

    DataInputStream ds = new DataInputStream(i);
    byte[] buffer = new byte[length];
    ds.readFully(buffer);       
    b.close();
    System.out.println(new String(buffer));

服务器稍微复杂一些，但重要的命令是：

return recv(handle, data, size, 0); //Read request header
return recv(handle, data, size, 0); //Read request payload
send(handle, data, size, 0); //Write response header
send(handle, data, size, 0); //Write response payload
//No Close only set socket handle to -1

有没有人知道发生了什么。我将不胜感激任何帮助和想法。

关闭TCP连接

0 个答案: