title: is it possible that some network packets are with null bytes?
body: <p>in network programming
  usually we use <code>recv()</code> or <code>recvfrom()</code> for receiving packets
  one of the argument is a string buffer,like</p>
  
  <pre><code> char buf[2000];
   recv(sockfd, buf, len, 0);
  </code></pre>
  
  <p>I'm wondering whether there are some null bytes( <code>0</code> or <code>\0</code>) in a packet
  if so, how to deal with this?
  thanks</p>