STM32F207做TFTP客户端收不到TFTP服务器的数据问题

 LwIP_Config();

    printf("ipaddr:%d.%d.%d.%d\r\n", net_ip[0], net_ip[1], net_ip[2], net_ip[3]);



    tftpd_init();

void tftpd_init(void)

{

  err_t err;

  unsigned port = 69;



  /* create a new UDP PCB structure  */

  UDPpcb = udp_new();

  if (!UDPpcb)

  {  /* Error creating PCB. Out of Memory  */

    return;

  }



  /* Bind this PCB to port 69  */

  err = udp_bind(UDPpcb, IP_ADDR_ANY, port);

  if (err != ERR_OK)

  {    /* Unable to bind to port  */

    return;

  }



  /* TFTP server start  */

  udp_recv(UDPpcb, recv_callback_tftp, NULL);

}

3、实现TFTP文件传输

3.1、文件传输协议实现

有了第2节的协议分析，我们基本了解了TFTP通信的协议，在这里，我们来实现TFTP的服务器端代码。



在监听的回调函数被触发调用时，首先从请求帧中获取操作码：

<div class="blockcode"><blockquote>tftp_opcode op = tftp_decode_op(pkt_buf->payload);  

  

switch (op)  

  {  

  

    case TFTP_RRQ:    /* TFTP RRQ (read request) */  

      tftp_extract_filename(FileName, pkt_buf->payload);  

      tftp_process_read(upcb, addr, port, FileName);  

      break;  

  

    case TFTP_WRQ:    /* TFTP WRQ (write request) */   

      tftp_extract_filename(FileName, pkt_buf->payload);  

      //在这个加入擦FALSH  

       tftp_process_write(upcb, addr, port, FileName);  

      break;  

  

    default:  

      /* sEndTransfera generic access violation message */  

      tftp_send_error_message(upcb, addr, port, TFTP_ERR_ACCESS_VIOLATION);  

      /* TFTP unknown request op */  

      /* no need to use tftp_cleanup_wr because no "tftp_connection_args" struct has been malloc'd   */  

      udp_remove(upcb);  

  

      break;  

  }  

int tftp_process_write(struct udp_pcb *upcb, struct ip_addr *to, int to_port, char *FileName)

{

  ... ...

  udp_recv(upcb, wrq_recv_callback, args);

  tftp_send_ack_packet(upcb, to, to_port, args->block);



  return 0;

}

void wrq_recv_callback(void *_args, struct udp_pcb *upcb, struct pbuf *pkt_buf, struct ip_addr *addr, u16_t port)

{

  tftp_connection_args *args = (tftp_connection_args *)_args;

  int n = 0;



  if (pkt_buf->len != pkt_buf->tot_len)

  {

    return;

  }



  /* Does this packet have any valid data to write? */

  if ((pkt_buf->len > TFTP_DATA_PKT_HDR_LEN) &&

      (tftp_extract_block(pkt_buf->payload) == (args->block + 1)))

  {

    /* 在这里处理接收到的数据pkt_buf->payload */



    /* update our block number to match the block number just received */

    args->block++;

    /* update total bytes  */

    (args->tot_bytes) += (pkt_buf->len - TFTP_DATA_PKT_HDR_LEN);



    /* This is a valid pkt but it has no data.  This would occur if the file being

       written is an exact multiple of 512 bytes.  In this case, the args->block

       value must still be updated, but we can skip everything else.    */

  }

  else if (tftp_extract_block(pkt_buf->payload) == (args->block + 1))

  {

    /* update our block number to match the block number just received  */

    args->block++;

  }



  /* SEndTransferthe appropriate ACK pkt (the block number sent in the ACK pkt echoes

   * the block number of the DATA pkt we just received - see RFC1350)

   * NOTE!: If the DATA pkt we received did not have the appropriate block

   * number, then the args->block (our block number) is never updated and

   * we simply sEndTransfera "duplicate ACK" which has the same block number as the

   * last ACK pkt we sent.  This lets the host know that we are still waiting

   * on block number args->block+1. */

  tftp_send_ack_packet(upcb, addr, port, args->block);



  /* If the last write returned less than the maximum TFTP data pkt length,

   * then we've received the whole file and so we can quit (this is how TFTP

   * signals the EndTransferof a transfer!)

   */

  if (pkt_buf->len < TFTP_DATA_PKT_LEN_MAX)

  {

    tftp_cleanup_wr(upcb, args);

    pbuf_free(pkt_buf);

  }

  else

  {

    pbuf_free(pkt_buf);

    return;

  }



}

    case TFTP_WRQ:    /* TFTP WRQ (write request) */ 

。    ... ...

      FlashDestination = HtmlDataAddress;

          /* Erase the needed pages where the user application will be loaded */

      /* Define the number of page to be erased */

      NbrOfPage = FLASH_PagesMask(HtmlTotalSize);//擦除HTML区域



      /* Erase the FLASH pages */

      FLASH_Unlock();

      for (EraseCounter = 0; (EraseCounter < NbrOfPage) && (FLASHStatus == FLASH_COMPLETE); EraseCounter++)

       {

         FLASHStatus = FLASH_ErasePage(HtmlSizeAddress + (PageSize * EraseCounter));

       }

      FLASH_Lock();

     filedata = (uint32_t)pkt_buf->payload + TFTP_DATA_PKT_HDR_LEN;

     FLASH_Unlock();

     for (n = 0;n < (pkt_buf->len - TFTP_DATA_PKT_HDR_LEN);n += 4)

     {

      /* Program the data received into STM32F10x Flash */

      FLASH_ProgramWord(FlashDestination, *(uint32_t*)filedata);



       if (*(uint32_t*)FlashDestination != *(uint32_t*)filedata)

        {

          /* End session */

         tftp_send_error_message(upcb, addr, port, FLASH_VERIFICATION_FAILED);

         /* close the connection */

         tftp_cleanup_wr(upcb, args); /* close the connection */

        }

        FlashDestination += 4;

        filedata += 4;

     }

     FLASH_Lock();