title: What is RTN short for in RTN_LOCAL?
body: <p>I am really confused with the name of RTN_LOCAL.</p>
  
  <p>It defined in linux/rtnetlink.h</p>
  
  <pre><code>enum {
  RTN_UNSPEC,
  RTN_UNICAST,        /* Gateway or direct route  */
  RTN_LOCAL,      /* Accept locally       */
  RTN_BROADCAST,      /* Accept locally as broadcast,
                 send as broadcast */
  RTN_ANYCAST,        /* Accept locally as broadcast,
                 but send as unicast */
  RTN_MULTICAST,      /* Multicast route      */
  RTN_BLACKHOLE,      /* Drop             */
  RTN_UNREACHABLE,    /* Destination is unreachable   */
  RTN_PROHIBIT,       /* Administratively prohibited  */
  RTN_THROW,      /* Not in this table        */
  RTN_NAT,        /* Translate this address   */
  RTN_XRESOLVE,       /* Use external resolver    */
  __RTN_MAX
  </code></pre>
  
  <p>};</p>
  
  <p><strong>I found it uesd in many places of Linux kernel.</strong></p>
  
  <p>1.the return value of inet_addr_type().</p>
  
  <p>2.route type value of fib_alias->fatype.</p>
  
  <p>3.action  value of fib_rule->action.</p>