Udp recvfrom stops receiving

Pavithra Shankar

Hi ,

I have a simple ndk udp application. I'm using a C6678 evm. i am trying to communicate with the ndk application from a pc connected to the board. The pc side implementation uses windows socket implementation.

i find that i am able to send and receive messages on both ends when my messages are of 10 bytes or below 10bytes. When my messages are above 10bytes i find that recvfrom remains blocked, it does not seem to come out of the blocked state. I'm sure i am missing out something silly. Does anybody have any suggestions on what i might be doing wrong?

I am using NDK 2.20.4.26.

over 13 years ago

0 Varada Bellary over 13 years ago

TI__Expert 5750 points

The problem you describe is really strange. The issue could be anywhere – either it’s the stack or lower driver layers.I will check with NDK expert if something stands out.

Here are some suggestions :

see if packet is coming across to the stack. Have you checked with flag ‘MSG_PEEK’ with ‘recvfrom’.
There are network stack statistics available to compare the successful packet recv v/s the other.
There is other API support, with ‘no copy’, called recvncfrom() and recvncfree(). There is example using these APIs, in “..\\mcsdk_2_xx_x_xx\examples\ndk\helloWorld”.

BTW : newer version of NDK is now available.

Hope this helps.

0 Pavithra Shankar over 13 years ago in reply to Varada Bellary

Prodigy 75 points

Thank you for your suggestions.

1. I checked the behavior when recvfrom is used with the MSG_PEEK flag. Does not seem to be making a difference. It did not provide any new insight.

2. How may i check these network stack statistics that u mention?

3. Using recvncfrom instead of recvfrom did not alter its behavior either. Messages above 10bytes still seem to be rejected.

Using Wireshark on the sending end PC i'm able to see the packets being sent out. Is there some way i can check on the evm 6678 side if packages are arriving or not?