title: check all socket opened in linux OS
body: <p>My program opens a socket with this function: </p>
  
  <blockquote>
    <p>sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)</p>
  </blockquote>
  
  <p>After finish sending data the socket is closed: </p>
  
  <blockquote>
    <p>close(sockfd);</p>
  </blockquote>
  
  <p>But the issue is when the program doesn't run well and is blocking. Thereby the socket will not be closed.  </p>
  
  <p>How can I check all sockets opened under Linux OS ?</p>