Need help with tcp-raw-api app. Wrong checksum sometimes calculatet ....THX !!!

[Steffen-16]

Hi @ all,

I have a urgent problem with a  Lwip-tcp-App. I use a standart raw api
tcp app except the sending function at the end of the file. The
applications works. The problem is, in some situations the tcp checksum
is wrong.
When i receive a PSH/ACK paket, i send a answere (tcp_recv_diag). This
works fine, but i have to send a second paket after a while (when
results of something are available). For this i've wrote a function
(SendDiagnoseMessage(u08 source_address, u08 destination_address, u08
*message, u16 length) you can find it at the end of the file).
This function  works most time fine, but sometimes the tcp-checksum of
exatly this paket is wrong.  The wrong checksum happens ONLY when 1ms
bevor i send this paket another paket is received (it seems the
connection gets asynchron).

thank you very much for your help Steffen

/*-----------------------------------------------------------------------------------*/

static void
tcp_conn_err_diag(void *arg, err_t err)
{

struct ETH_Diagnose_Struct *hs;

LWIP_UNUSED_ARG(err);

hs = arg;
mem_free(hs);
}
/*-----------------------------------------------------------------------------------*/

static void
tcp_close_conn_diag(struct tcp_pcb *pcb, struct ETH_Diagnose_Struct *hs)
{
tcp_arg(pcb, NULL);
tcp_sent(pcb, NULL);
tcp_recv(pcb, NULL);
if(hs!=NULL)
{  mem_free(hs);}
tcp_close(pcb);
}
/*-----------------------------------------------------------------------------------*/


static void
tcp_send_data_diag(struct tcp_pcb *pcb, struct ETH_Diagnose_Struct *hs)
{
err_t err;
u16_t len;

/* We cannot send more data than space available in the send
  buffer. */
if (tcp_sndbuf(pcb) < hs->left)
{
 len = tcp_sndbuf(pcb);
}
else
{
 len = hs->left;
}




do
{
 err = tcp_write(pcb, hs->file, len, 1);
 tcp_output(pcb);
 /*Changed from ,0 to ,
  * The copy argument is either 0 or 1 and indicates
  * whether the new memory should be allocated for the data to be copied
into. */
 if (err == ERR_MEM)
 {
   len /= 2;
 }
} while (err == ERR_MEM && len > 1);

if (err == ERR_OK)
{
 hs->file += len;
 hs->left -= len;
 /*  } else {
 printf("send_data: error %s len %d %d\n", lwip_strerr(err), len,
tcp_sndbuf(pcb));*/

}
}
/*-----------------------------------------------------------------------------------*/

static err_t
tcp_poll_diag(void *arg, struct tcp_pcb *pcb)
{
struct ETH_Diagnose_Struct *hs;

hs = arg;

/*  printf("Poll\n");*/
if (hs == NULL)
{
 /*    printf("Null, close\n");*/
 tcp_abort(pcb);
 return ERR_ABRT;
}
else
{
 ++hs->retries;
 if (hs->retries == 4)
 {
   // disable automatic connection closing
   //tcp_abort(pcb);
   return ERR_ABRT;
 }
 tcp_send_data_diag(pcb, hs);
}
return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/

static s08
tcp_sent_diag(void *arg, struct tcp_pcb *pcb, u16_t len)
{
struct ETH_Diagnose_Struct *hs;

LWIP_UNUSED_ARG(len);

hs = arg;

hs->retries = 0;

if (hs->left > 0)
{
   tcp_send_data_diag(pcb, hs);
}
else
{
   // clear if connection should not be closed
   //tcp_close_conn_diag(pcb, hs);
}

return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/


static err_t
tcp_recv_diag(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
{

struct ETH_Diagnose_Struct *hs_send_diagnose_message;

 hs_send_diagnose_message = arg;

if (err == ERR_OK && p != NULL)
{
   /* Inform TCP that we have taken the data. */
   tcp_recved(pcb, p->tot_len);

   if (hs_send_diagnose_message->file == NULL )
   {

       // Handle received message
       //------------------------
       hs_send_diagnose_message->left = ProcessDiagPacket (p->payload,
p->len);
       hs_send_diagnose_message->file = ack_buf;

       if(hs_send_diagnose_message->left >0)
         {
             // send reply
             pbuf_free(p);
             tcp_send_data_diag(pcb, hs_send_diagnose_message);
             tcp_sent(pcb, tcp_sent_diag);


         }
         else
         {
             //WrongMsgReceived
             pbuf_free(p);
         }
   }
   else
   {
       pbuf_free(p);
   }
}

//send_data(pcb, hs);
if (err == ERR_OK && p == NULL)
{
 tcp_close_conn_diag(pcb, hs_send_diagnose_message);
}

return ERR_OK;
}

/*-----------------------------------------------------------------------------------*/

static err_t
tcp_accept_diag(void *arg, struct tcp_pcb *pcb, err_t err)
{
struct ETH_Diagnose_Struct *hs;

LWIP_UNUSED_ARG(arg);
LWIP_UNUSED_ARG(err);

tcp_setprio(pcb, TCP_PRIO_MIN);

/* Allocate memory for the structure that holds the state of the
  connection. */
hs = (struct ETH_Diagnose_Struct *)mem_malloc(sizeof(struct
ETH_Diagnose_Struct));

if (hs == NULL) {
 return ERR_MEM;
}


/* Initialize the structure. */
hs->file = NULL;
hs->left = 0;
hs->retries = 0;

/* Tell TCP that this is the structure we wish to be passed for our
  callbacks. */
tcp_arg(pcb, hs);

/* Tell TCP that we wish to be informed of incoming data by a call
  to the http_recv() function. */
tcp_recv(pcb, tcp_recv_diag);

tcp_err(pcb, tcp_conn_err_diag);

tcp_poll(pcb, tcp_poll_diag, 4);
return ERR_OK;
}
/*-----------------------------------------------------------------------------------*/

void
tcp_init_diag(void)
{
struct tcp_pcb *pcb;

pcb = tcp_new();
tcp_bind(pcb, IP_ADDR_ANY, DIAGNOSE_TCP_PORT);
pcb = tcp_listen(pcb);
tcp_accept(pcb, tcp_accept_diag);
}
/*-----------------------------------------------------------------------------------*/


void SendDiagnoseMessage(u08 source_address, u08 destination_address,
u08 *message, u16 length)
{

 struct ETH_Diagnose_Struct *hs_send_diagnose_message;
 struct tcp_pcb *apcbs = tcp_active_pcbs;
 u32 i=0;

 while (apcbs != NULL)
 {
         if (apcbs->local_port == DIAGNOSE_TCP_PORT)
         {
             hs_send_diagnose_message = apcbs->callback_arg;

             if (hs_send_diagnose_message->file == NULL  )
             {

                 /* build tcp_diag_response_header */
                 DiagResponseHeader->len = (u32)length + DIAG_ADDRESS_LEN;
                 DiagResponseHeader->ctrl_word = DIAG_RESP_CW;
                 DiagResponseHeader->source = source_address;
                 DiagResponseHeader->target = destination_address;

                 /* copy payload */
                 for(i=0; i < length; i++)
                 {
                     diag_buf[i+ HEADER_LEN + DIAG_ADDRESS_LEN] = *message;
                     message++;
                 }


                 hs_send_diagnose_message->file = (u08*)&diag_buf;
                 hs_send_diagnose_message->left = length + HEADER_LEN +
DIAG_ADDRESS_LEN;

                 if(hs_send_diagnose_message->left >0)
                 {
                     tcp_send_data_diag(apcbs, hs_send_diagnose_message);
                     tcp_sent(apcbs, tcp_sent_diag);
                 }
             }
             break;
         }
         apcbs = apcbs->next;
 }
}



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You didn't say from where you call the SendDiagnoseMessage() function
(i.e. which thread). Most often, things like checksum corruption (or
corruption of linked lists etc.) result from multiple threads being
active in the lwIP code at the same time. You should make sure that this
is not the case by using tcpip_callback() when another thread wants to
execute SendDiagnoseMessage() (this makes sure the function runs in the
correct thread context).

Simon


Steffen schrieb:

> [..]
> void SendDiagnoseMessage(u08 source_address, u08 destination_address,
> u08 *message, u16 length)
> {
>
>  struct ETH_Diagnose_Struct *hs_send_diagnose_message;
>  struct tcp_pcb *apcbs = tcp_active_pcbs;
>  u32 i=0;
>
>  while (apcbs != NULL)
>  {
>          if (apcbs->local_port == DIAGNOSE_TCP_PORT)
>          {
>              hs_send_diagnose_message = apcbs->callback_arg;
>
>              if (hs_send_diagnose_message->file == NULL  )
>              {
>
>                  /* build tcp_diag_response_header */
>                  DiagResponseHeader->len = (u32)length + DIAG_ADDRESS_LEN;
>                  DiagResponseHeader->ctrl_word = DIAG_RESP_CW;
>                  DiagResponseHeader->source = source_address;
>                  DiagResponseHeader->target = destination_address;
>
>                  /* copy payload */
>                  for(i=0; i < length; i++)
>                  {
>                      diag_buf[i+ HEADER_LEN + DIAG_ADDRESS_LEN] = *message;
>                      message++;
>                  }
>
>
>                  hs_send_diagnose_message->file = (u08*)&diag_buf;
>                  hs_send_diagnose_message->left = length + HEADER_LEN +
> DIAG_ADDRESS_LEN;
>
>                  if(hs_send_diagnose_message->left >0)
>                  {
>                      tcp_send_data_diag(apcbs, hs_send_diagnose_message);
>                      tcp_sent(apcbs, tcp_sent_diag);
>                  }
>              }
>              break;
>          }
>          apcbs = apcbs->next;
>  }
> }
>
>
>
> _______________________________________________
> lwip-users mailing list
> lwip-users@...
> http://lists.nongnu.org/mailman/listinfo/lwip-users
>
>  

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[Bill Auerbach]

Also, the target wasn't mentioned.  This also sounds like a driver and/or
hardware problem as well.

Bill

>-----Original Message-----
>From: lwip-users-bounces+bauerbach=arrayonline.com@...
>[mailto:lwip-users-bounces+bauerbach=arrayonline.com@...] On
>Behalf Of goldsimon@...
>Sent: Sunday, November 08, 2009 12:29 PM
>To: Mailing list for lwIP users
>Subject: Re: [lwip-users] Need help with tcp-raw-api app. Wrong checksum
>sometimes calculatet ....THX !!!
>
>You didn't say from where you call the SendDiagnoseMessage() function
>(i.e. which thread). Most often, things like checksum corruption (or
>corruption of linked lists etc.) result from multiple threads being
>active in the lwIP code at the same time. You should make sure that this
>is not the case by using tcpip_callback() when another thread wants to
>execute SendDiagnoseMessage() (this makes sure the function runs in the
>correct thread context).
>
>Simon
>
>
>Steffen schrieb:
>> [..]
>> void SendDiagnoseMessage(u08 source_address, u08 destination_address,
>> u08 *message, u16 length)
>> {
>>
>>  struct ETH_Diagnose_Struct *hs_send_diagnose_message;
>>  struct tcp_pcb *apcbs = tcp_active_pcbs;
>>  u32 i=0;
>>
>>  while (apcbs != NULL)
>>  {
>>          if (apcbs->local_port == DIAGNOSE_TCP_PORT)
>>          {
>>              hs_send_diagnose_message = apcbs->callback_arg;
>>
>>              if (hs_send_diagnose_message->file == NULL  )
>>              {
>>
>>                  /* build tcp_diag_response_header */
>>                  DiagResponseHeader->len = (u32)length +
>DIAG_ADDRESS_LEN;
>>                  DiagResponseHeader->ctrl_word = DIAG_RESP_CW;
>>                  DiagResponseHeader->source = source_address;
>>                  DiagResponseHeader->target = destination_address;
>>
>>                  /* copy payload */
>>                  for(i=0; i < length; i++)
>>                  {
>>                      diag_buf[i+ HEADER_LEN + DIAG_ADDRESS_LEN] =
>*message;
>>                      message++;
>>                  }
>>
>>
>>                  hs_send_diagnose_message->file = (u08*)&diag_buf;
>>                  hs_send_diagnose_message->left = length + HEADER_LEN
>+
>> DIAG_ADDRESS_LEN;
>>
>>                  if(hs_send_diagnose_message->left >0)
>>                  {
>>                      tcp_send_data_diag(apcbs,
>hs_send_diagnose_message);
>>                      tcp_sent(apcbs, tcp_sent_diag);
>>                  }
>>              }
>>              break;
>>          }
>>          apcbs = apcbs->next;
>>  }
>> }
>>
>>
>>
>> _______________________________________________
>> lwip-users mailing list
>> lwip-users@...
>> http://lists.nongnu.org/mailman/listinfo/lwip-users
>>
>>
>
>
>
>_______________________________________________
>lwip-users mailing list
>lwip-users@...
>http://lists.nongnu.org/mailman/listinfo/lwip-users

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[Steffen-16]

Thx for your fast answeres ! I don't use an operating system, so i don't have threads.  The target is a PowerPc MPC5567. I call the "SendDiagnoseMessage()" function, when results from another Bussystem are available.
My ETH Controller is in Interrupt mode ! When calling the "SendDiagnoseMessage()" function,it is possible i get interrupted by the receive Interrupt of the ETH controller,
 (I told you that the wrong checksum only occurs, when a paket is received 1ms bevor i send with"SendDiagnoseMessage()"). I think normaly this should be no problem because the receive function allocates a new pbuf  which is another than the send pbuf.
But the SEQ and ACK number is counted up at this time (i received a PSH/ACK packet 1 ms second bevor i send so i have to count up the SEQ ACK numbers too, to be synchron. Maybe my packet is build already at this time). This is only speculation i hope you have any idea, what i can do..

I know from other devices who work withz the same Pc app , they send two pakets in series. (In my code you can see, i send an reply in the "tcp_recv_diag" and when the result is available a result paket). So they wait till the result is availbale an then they send both packets
in series without an ACK between them. I've tried this too, but the LWIP  waits after one packet for an ACK and send the second after that. Isa it possible to send to PSH/ACK pakets diretly in series without an ACK between them. I think this will solve my problem.

Steffen 


Bill Auerbach schrieb:

Also, the target wasn't mentioned.  This also sounds like a driver and/or
hardware problem as well.

Bill

  

-----Original Message-----
From: lwip-users-bounces+bauerbach=arrayonline.com@...
[lwip-users-bounces+bauerbach=arrayonline.com@...] On
Behalf Of goldsimon@...
Sent: Sunday, November 08, 2009 12:29 PM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] Need help with tcp-raw-api app. Wrong checksum
sometimes calculatet ....THX !!!

You didn't say from where you call the SendDiagnoseMessage() function
(i.e. which thread). Most often, things like checksum corruption (or
corruption of linked lists etc.) result from multiple threads being
active in the lwIP code at the same time. You should make sure that this
is not the case by using tcpip_callback() when another thread wants to
execute SendDiagnoseMessage() (this makes sure the function runs in the
correct thread context).

Simon


Steffen schrieb:
    

[..]
void SendDiagnoseMessage(u08 source_address, u08 destination_address,
u08 *message, u16 length)
{

 struct ETH_Diagnose_Struct *hs_send_diagnose_message;
 struct tcp_pcb *apcbs = tcp_active_pcbs;
 u32 i=0;

 while (apcbs != NULL)
 {
         if (apcbs->local_port == DIAGNOSE_TCP_PORT)
         {
             hs_send_diagnose_message = apcbs->callback_arg;

             if (hs_send_diagnose_message->file == NULL  )
             {

                 /* build tcp_diag_response_header */
                 DiagResponseHeader->len = (u32)length +
      

DIAG_ADDRESS_LEN;
    

                 DiagResponseHeader->ctrl_word = DIAG_RESP_CW;
                 DiagResponseHeader->source = source_address;
                 DiagResponseHeader->target = destination_address;

                 /* copy payload */
                 for(i=0; i < length; i++)
                 {
                     diag_buf[i+ HEADER_LEN + DIAG_ADDRESS_LEN] =
      

*message;
    

                     message++;
                 }


                 hs_send_diagnose_message->file = (u08*)&diag_buf;
                 hs_send_diagnose_message->left = length + HEADER_LEN
      

+
    

DIAG_ADDRESS_LEN;

                 if(hs_send_diagnose_message->left >0)
                 {
                     tcp_send_data_diag(apcbs,
      

hs_send_diagnose_message);
    

                     tcp_sent(apcbs, tcp_sent_diag);
                 }
             }
             break;
         }
         apcbs = apcbs->next;
 }
}



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[Bill Auerbach]

Some parts of this message have been removed. Learn more about Nabble's security policy.

Steffen, did you start a DMA packet send and then return immediately from low_level_output?  If you do this, lwIP will pbuf_free the packet while it’s still in transfer.  If you send packets quickly and the checksum fails, not but if you send slowly, this is a symptom of this problem.

 

Bill

 

From: lwip-users-bounces+bauerbach=arrayonline.com@... [mailto:lwip-users-bounces+bauerbach=arrayonline.com@...] On Behalf Of Steffen
Sent: Monday, November 09, 2009 4:05 PM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] Need help with tcp-raw-api app. Wrong checksum sometimes calculatet ....THX !!!

 

Thx for your fast answeres ! I don't use an operating system, so i don't have threads.  The target is a PowerPc MPC5567. I call the "SendDiagnoseMessage()" function, when results from another Bussystem are available.
My ETH Controller is in Interrupt mode ! When calling the "SendDiagnoseMessage()" function,it is possible i get interrupted by the receive Interrupt of the ETH controller,
 (I told you that the wrong checksum only occurs, when a paket is received 1ms bevor i send with"SendDiagnoseMessage()"). I think normaly this should be no problem because the receive function allocates a new pbuf  which is another than the send pbuf.
But the SEQ and ACK number is counted up at this time (i received a PSH/ACK packet 1 ms second bevor i send so i have to count up the SEQ ACK numbers too, to be synchron. Maybe my packet is build already at this time). This is only speculation i hope you have any idea, what i can do..

I know from other devices who work withz the same Pc app , they send two pakets in series. (In my code you can see, i send an reply in the "tcp_recv_diag" and when the result is available a result paket). So they wait till the result is availbale an then they send both packets
in series without an ACK between them. I've tried this too, but the LWIP  waits after one packet for an ACK and send the second after that. Isa it possible to send to PSH/ACK pakets diretly in series without an ACK between them. I think this will solve my problem.

Steffen 


Bill Auerbach schrieb:

Also, the target wasn't mentioned.  This also sounds like a driver and/or

hardware problem as well.

Bill

-----Original Message-----

From: lwip-users-bounces+bauerbach=arrayonline.com@...

[lwip-users-bounces+bauerbach=arrayonline.com@...] On

Behalf Of goldsimon@...

Sent: Sunday, November 08, 2009 12:29 PM

To: Mailing list for lwIP users

Subject: Re: [lwip-users] Need help with tcp-raw-api app. Wrong checksum

sometimes calculatet ....THX !!!

You didn't say from where you call the SendDiagnoseMessage() function

(i.e. which thread). Most often, things like checksum corruption (or

corruption of linked lists etc.) result from multiple threads being

active in the lwIP code at the same time. You should make sure that this

is not the case by using tcpip_callback() when another thread wants to

execute SendDiagnoseMessage() (this makes sure the function runs in the

correct thread context).

Simon

Steffen schrieb:

[..]

void SendDiagnoseMessage(u08 source_address, u08 destination_address,

u08 *message, u16 length)

{

 struct ETH_Diagnose_Struct *hs_send_diagnose_message;

 struct tcp_pcb *apcbs = tcp_active_pcbs;

 u32 i=0;

 while (apcbs != NULL)

 {

         if (apcbs->local_port == DIAGNOSE_TCP_PORT)

         {

             hs_send_diagnose_message = apcbs->callback_arg;

             if (hs_send_diagnose_message->file == NULL  )

             {

                 /* build tcp_diag_response_header */

                 DiagResponseHeader->len = (u32)length +

DIAG_ADDRESS_LEN;

                 DiagResponseHeader->ctrl_word = DIAG_RESP_CW;

                 DiagResponseHeader->source = source_address;

                 DiagResponseHeader->target = destination_address;

                 /* copy payload */

                 for(i=0; i < length; i++)

                 {

                     diag_buf[i+ HEADER_LEN + DIAG_ADDRESS_LEN] =

*message;

                     message++;

                 }

                 hs_send_diagnose_message->file = (u08*)&diag_buf;

                 hs_send_diagnose_message->left = length + HEADER_LEN

+

DIAG_ADDRESS_LEN;

                 if(hs_send_diagnose_message->left >0)

                 {

                     tcp_send_data_diag(apcbs,

hs_send_diagnose_message);

                     tcp_sent(apcbs, tcp_sent_diag);

                 }

             }

             break;

         }

         apcbs = apcbs->next;

 }

}

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Steffen wrote:

> Thx for your fast answeres ! I don't use an operating system, so i don't
> have threads.  The target is a PowerPc MPC5567. I call the
> "SendDiagnoseMessage()" function, when results from another Bussystem
> are available.
> My ETH Controller is in Interrupt mode ! When calling the
> "SendDiagnoseMessage()" function,it is possible i get interrupted by the
> receive Interrupt of the ETH controller,
>  (I told you that the wrong checksum only occurs, when a paket is
> received 1ms bevor i send with"SendDiagnoseMessage()"). I think normaly
> this should be no problem because the receive function allocates a new
> pbuf  which is another than the send pbuf.

Do you only allocate a pbuf in interrupt context or do you also pass this pbuf into the stack? With interrupt context, it's the same as multithreading: it's not supported. Instead, put the received pbuf on a list and process this list in the main application context.

Simon
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