#include <asm/types.h>
       #include <linux/netlink.h>
       #include <linux/rtnetlink.h>
       #include <sys/socket.h>

All  rtnetlink(7)  messages  consist of a netlink(7) message header and
       appended attributes.  The attributes should be only  manipulated  using
       the macros provided here.

       RTA_OK(rta,  attrlen)  returns  true  if  rta points to a valid routing

#include <asm/types.h>
       #include <linux/netlink.h>
       #include <linux/rtnetlink.h>
       #include <sys/socket.h>

Rtnetlink  allows  the  kernel's routing tables to be read and altered.
       It is used within the kernel to communicate between various subsystems,
       though  this  usage  is not documented here, and for communication with
       user-space programs.  Network routes, IP  addresses,  link  parameters,
       neighbor  setups,  queueing  disciplines,  traffic  classes  and packet