Re: [lwip-users] Need support on TCP/IP packet transmission

[goldsimon]

Am 20. Februar 2020 15:23:55 MEZ schrieb praveenkumar raavi <address@hidden>:
>Hi,
>
>Any update on my query...

I'm not sure I even understand what your actual problem is. But being stuck in 
the timer function surely sounds like a threading problem...

Regards,
Simon

>
>Regards,
>PraveenKumar.
>
>On Thu, 13 Feb 2020, 09:54 praveenkumar raavi,
><address@hidden>
>wrote:
>
>> Hi Everyone,
>>
>>
>>
>> we are using LWIP 2.0.3 for one of our project to establish the TCP
>> connection from ECU and Atmel micro.
>> We got the LWIP from Atmel itself and I have modified little to
>support
>> VLAN data receive and transmit.
>>
>>
>>
>> But now we are seeing some issue during data transmission.
>> When the ECU goes to sleep, it cut down the Ethernet link and when it
>> wakes up it will establish the Ethernet connection.
>> But here when the ECU wakes up the communication is not going well
>from
>> our LWIP stack. We are seeing multiple re transmissions which are
>causing
>> issues in data transmission.
>>
>> So we planned to reinitialize the LWIP stack after ECU goes to sleep.
>> But when I do shut down the connection, the connection is not closing
>as
>> there is no FIN request response from ECU and its getting stuck in
>tcp_slow
>> timer.
>> Also I have seen new behavior like when i received new frame on TCP,
>I am
>> trying to ACK back using ACK now function(pcb->prio = TCP_PRIO_MAX;
>> tcp_send_empty_ack(pcb);  tcp_output(pcb);), but I am seeing the ACK
>> packet transmitted after my data packet is been transferred.
>> This I didn't understand like why the ACK packet is transferred after
>data
>> packet? this is also one of the reason for us to see communication
>failure.
>>
>> I am attaching the images for our communication issues.
>> Here LWIP_IP: 192.168.6.182
>>      ECU IP : 192.168.6.144
>> If you see LWIP_TCP_DataSentoutFirst.JPG, the data is send first and
>ACK
>> is sent after that even though the ACK transmission is initiated
>first with
>> priority level set to MAX.
>>
>> Please let us know how to solve this issue.
>>
>>
>>
>> I am adding following steps during lwip init.
>>
>> TCPIP_STACK_INTERFACE_0_init(st_ETH_ConfigStruct.u8_SourceMacAddress,
>> Src_IP, gw);
>>
>> netif_set_up(&TCPIP_STACK_INTERFACE_0_desc);
>>
>> netif_set_default(&TCPIP_STACK_INTERFACE_0_desc);
>>
>> mac_async_enable(&MACIF);
>>
>> etharp_add_static_entry(&Dest_IP, (struct eth_addr
>> *)&st_ETH_ConfigStruct.u8_DestMacAddress[0]);
>>
>> pcb_tcp = tcp_new();
>>
>> error = tcp_bind(pcb_tcp, &address,
>st_ETH_ConfigStruct.u16_SourcePortNum);
>>
>> pcb_tcp = tcp_listen(pcb_tcp);
>>
>> tcp_accept(pcb_tcp, Etherdo_connected);
>>
>>
>>
>> After link established, below functions are used to do data transfer.
>>
>>
>>
>> tcp_write(pcb_tcp,u8_DataBuff,u16_DataLen,TCP_WRITE_FLAG_MORE);
>>
>> tcp_output(pcb_tcp));
>>
>>
>>
>> This is how I initialized LWIP stack and transmitting data over
>ethernet.
>> Here I have used static MAC address as we should connect to
>particular MAC
>> address.
>>
>>
>> Regards,
>>
>> PraveenKumar.
>>