EK-TM4C1294XL: Socket connection status : live or not

R & D

I have created a TCP server using MCU. Now when I am sending and receiving data to/from the TCP client I am able to know if the client is still connected to my device or not. But when there is no data sharing I am completely blind about the status of the connection between the server and the client.

I am using Hercules software to simulate it as TCP client.

Now following one of the threads of TI forum https://e2e.ti.com/support/processors-group/processors/f/processors-forum/392427/ndk-socket-is-live-or-not/1394606#1394606 (link of the thread) I used getpeername api to get the IP address of the connected client. So when the client is connected I get the correct IP address. But when I have broken the connection through hercules software even though I am getting the correct IP address which is quite confusing to me,

Please help me with this.

Thanks in advance.

over 2 years ago

0 Charles Tsai over 2 years ago

TI__Guru**** 191886 points

Hi,

R & D said:
So when the client is connected I get the correct IP address. But when I have broken the connection through hercules software even though I am getting the correct IP address which is quite confusing to me,

What is the return value of getpeername(). If it is not zero then there is an error. What is the error?

When the connection is broken and if you issue a ping command, does the ICMP echo message show up on the network? Please use Wireshark to look at the network traffic for ICMP echo messages. Does any host on the network respond to the echo request?

0 R & D over 2 years ago in reply to Charles Tsai

Intellectual 560 points

Hi,

The return value of the getpeername() function is zero. Also when I ping through TCP client to the server I am getting the ping but still I am unable to ping through the TCP server as mentioned in the the previous thread : https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1263892/ek-tm4c1294xl-how-to-use-icmpgenpacket-and-icmpsendrtadv-api-to-ping-a-tcp-client/4793561#4793561

0 Charles Tsai over 2 years ago in reply to R & D

TI__Guru**** 191886 points

Hi,

R & D said:
Also when I ping through TCP client to the server I am getting the ping

Is this a ping from your PC? Or you create a client on a different TM4c129 MCU and use the Ping() command?

R & D said:
but still I am unable to ping through the TCP server as mentioned in the the previous thread

Sorry, I really don't know why it would work for the client but not the server. I'm not an expert in the NDK and ICMP specifically. My understanding is that ICMP is a peer to peer operation. If you can Ping() function to work on a client then it should work on a server. Have you look at the wireshark? Is it possible that some internal cache is still holding the old IP after the disconnect?

I want to give you a heads-up here. I will be on vacation starting tomorrow for the rest of the week. My response will be extremely delayed.

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EK-TM4C1294XL: Socket connection status : live or not