LM3开发笔记_8.Telnet协议的串口服务器

快到年关了，项目上非常忙，很久没来了。今天抽空把俺的串口服务器Telnet协议部分整理了一下。

串口服务器可以将telnet发送的指令通过串口转发到对应的设备，来获取设备状态和控制设备。比如查看设备的电流，电压和温度等等。

直接上代码，有问题可跟贴。

// 握手字符串

#define HANDSHAKE "Serial Server v1.0 Telnet System!\r\n"

// Telnet接收处理函数
static err_t TelnetCmd_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
{
 struct pbuf *q;
 CMDSTRUCT *pReceiveCmd;
 CMDSTRUCT SendCmd;
 static bool bAccepting = FALSE;
 int done;
 char *Word;
 char ch;
 int i;
 
 pReceiveCmd = (CMDSTRUCT *)arg;

 /* We perform here any necessary processing on the pbuf */
 if (p != NULL)
 {
  tcp_recved(pcb, p->tot_len);
  
  if(!pReceiveCmd)
  {
   pbuf_free(p);
   return ERR_ARG;
  }
  
  done = 0;
  for(q=p; q != NULL; q = q->next)
  {
   Word = q->payload;
   for(i=0; i<q->len && !done; i++)
   {
    ch = Word;
    if('$' == ch)
    {
     bAccepting = TRUE;
     pReceiveCmd->length = 0;
    }   
    if(bAccepting)
    {
     if(pReceiveCmd->length < CMDBUFFERSIZE)
      pReceiveCmd->bytes[pReceiveCmd->length++] = ch;
     if(';' == ch || pReceiveCmd->length >= CMDBUFFERSIZE)
     {
      bAccepting = FALSE;
      done = 1;
     }
    }
   }
  }
  if(done)
  {
   if(UartApp_SendData(pReceiveCmd,&SendCmd))
   {
    tcp_write(pcb, SendCmd.bytes, SendCmd.length, TCP_WRITE_FLAG_COPY);
   }
   pReceiveCmd->length = 0;
  }
  /* End of processing, we free the pbuf */
  pbuf_free(p);
 }
 else if (err == ERR_OK)
 {
  mem_free(pReceiveCmd);
  return tcp_close(pcb);
 }
 return ERR_OK;
}