code: def rpc_atlas_peer_exchange(self, remote_peer, **con_info):
          
          conf = get_blockstack_opts()
          if not conf.get('atlas', False):
              return {'error': 'Not an atlas node', 'http_status': 404}
  
          # take the socket-given information if this is not localhost
          client_host = con_info['client_host']
          client_port = con_info['client_port']
  
          peer_host = None
          peer_port = None
          
          LOCALHOST = ['127.0.0.1', '::1', 'localhost']
          if client_host not in LOCALHOST:
              # we don't allow a non-localhost peer to insert an arbitrary host
              peer_host = client_host
              peer_port = client_port
  
          else:
              try:
                  peer_host, peer_port = url_to_host_port(remote_peer)
                  assert peer_host
                  assert peer_port
              except:
                  # invalid
                  return {'error': 'Invalid remote peer address', 'http_status': 400}
          
          peers = self.peer_exchange(peer_host, peer_port)
          return self.success_response({'peers': peers})
docs: Accept a remotely-given atlas peer, and return our list
          of healthy peers.  The remotely-given atlas peer will only
          be considered if the caller is localhost; otherwise, the caller's
          socket-given information will be used.  This is to prevent
          a malicious node from filling up this node's peer table with
          junk.
  
          Returns at most atlas_max_neighbors() peers
          Returns {'status': True, 'peers': ...} on success
          Returns {'error': ...} on failure