code: func (d *transportDemuxer) deliverControlPacket(net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ ControlType, extra uint32, vv buffer.VectorisedView, id TransportEndpointID) bool {
  	eps, ok := d.protocol[protocolIDs{net, trans}]
  	if !ok {
  		return false
  	}
  
  	// Try to find the endpoint.
  	eps.mu.RLock()
  	ep := d.findEndpointLocked(eps, vv, id)
  	eps.mu.RUnlock()
  
  	// Fail if we didn't find one.
  	if ep == nil {
  		return false
  	}
  
  	// Deliver the packet.
  	ep.HandleControlPacket(id, typ, extra, vv)
  
  	return true
  }
docs: // deliverControlPacket attempts to deliver the given control packet. Returns
  // true if it found an endpoint, false otherwise.