old_contents: #!/usr/bin/env python
  
  import traceback
  from pyroute2.netlink import NLM_F_REQUEST
  from pyroute2.netlink.client import GenericNetlink
  from pyroute2.netlink.generic import genlmsg
  
  
  RLINK_CMD_UNSPEC = 0
  RLINK_CMD_REQ = 1
  
  
  class rcmd(genlmsg):
      '''
      Message class that will be used to communicate
      with the kernel module
      '''
      nla_map = (('RLINK_ATTR_UNSPEC', 'none'),
                 ('RLINK_ATTR_DATA', 'asciiz'))
  
  
  class Rlink(GenericNetlink):
      '''
      Custom generic netlink protocol. Has one method,
      `hello_world()`, the only netlink call of the kernel
      module.
      '''
      def hello_world(self):
          msg = rcmd()
          msg['cmd'] = RLINK_CMD_REQ
          msg['version'] = 1
          ret = self.nlm_request(msg,
                                 self.prid,
                                 msg_flags=NLM_F_REQUEST)[0]
          return ret.get_attr('RLINK_ATTR_DATA')
  
  try:
      # create protocol instance
      rlink = Rlink('EXMPL_GENL', rcmd)
      # request a method
      print(rlink.hello_world())
  except:
      # if there was an error, log it to the console
      traceback.print_exc()
  finally:
      # finally -- release the instance
      rlink.release()
  
new_contents: #!/usr/bin/env python
  
  import traceback
  from pyroute2.netlink import NLM_F_REQUEST
  from pyroute2.netlink import genlmsg
  from pyroute2.netlink.generic import GenericNetlinkSocket
  
  
  RLINK_CMD_UNSPEC = 0
  RLINK_CMD_REQ = 1
  
  
  class rcmd(genlmsg):
      '''
      Message class that will be used to communicate
      with the kernel module
      '''
      nla_map = (('RLINK_ATTR_UNSPEC', 'none'),
                 ('RLINK_ATTR_DATA', 'asciiz'))
  
  
  class Rlink(GenericNetlinkSocket):
      '''
      Custom generic netlink protocol. Has one method,
      `hello_world()`, the only netlink call of the kernel
      module.
      '''
      def hello_world(self):
          msg = rcmd()
          msg['cmd'] = RLINK_CMD_REQ
          msg['version'] = 1
          ret = self.nlm_request(msg,
                                 self.prid,
                                 msg_flags=NLM_F_REQUEST)[0]
          return ret.get_attr('RLINK_ATTR_DATA')
  
  try:
      # create protocol instance
      rlink = Rlink()
      rlink.bind('EXMPL_GENL', rcmd)
      # request a method
      print(rlink.hello_world())
  except:
      # if there was an error, log it to the console
      traceback.print_exc()
  finally:
      # finally -- release the instance
      rlink.close()
  
subject: use the new module layout and API