• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 99 subscribers
  • Views 650 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LWIP UDP echo problem with big packet

Mohsen Taheri
Intellectual 510 points


Hi

I am using a custom board based on Beaglebone and I am developing a software by Starterware_02_00_01_01. I made some codes to echo packet in UDP protocol.

Everything was OK and the all packets were echoed correctly. But, when I increased the packet size to about 130 bytes, not only the packets was not echoed, but also I observed the program crashed so that the PC(Program counter) went to an unknown place.

Could anyone please help me to overcome the problem.

thanks,

Mohsen

  • 0
    Prodigy 120 points

    Hi

     

    First I want to mention is a classical -- memory corruption. Since there is no information about helpers and technics you use in lwIP callback functions (or you use polling?), I guess in some of your packet intake functions a memory corruption occurs (maybe due to incorrect pointer operations -- most often case).

    So I see 2 methods of going further

    -- turn off echoes at all in order to reduce error impact

    -- very carefully recheck entire pointer management + validate usage of lwIP-supplied ones

  • 0 in reply to Feu van Strike
    Intellectual 510 points

    Hi Feu

    Thanks for your advice.

    I turned off echo packet in receive callback function. Instead, I made echo mechanism using global buffer and  a flag in the main loop. It worked perfect until I increased the packet size to more than 700 byte. After that the old story happened, program crashing.

    I think you are right about memory corruption, but as the memory management of lwip is not under my control I can not solve the problem.

    It is currently enough for me to echo 512 byte, so I put this problem off to later time.

    thanks

    Amin