title: linux kernel icmp implementation question
body: <p>in the current linux kernel,</p>
  
  <p>when ICMP module receives ECHO REQUEST message, does it check or limit the data size?
  or does it just puts the data in a new ICMP message and send back to the source?</p>
  
  <p>I been reading the source code, and I am pretty sure the kernel doesn't check the data size but I want to make it sure :) </p>