[Click] question for ipfilter

[wang houfen]

Hello,

What  functionality hat the following function negation_is_simple() and what for is the function used?

inline bool
IPFilter::Primitive::negation_is_simple() const
{
  if (_type == TYPE_PROTO)
    return true;
  else if (_transp_proto >= 0)
    return false;
  else
    return _type == TYPE_HOST || (_type & TYPE_FIELD) || _type == TYPE_IPFRAG;
} 


Why is packet_length = p->length() + TRANSP_FAKE_OFFSET - p->transport_header_offset() from IPFilter::length_checked_push(Packet *p)?


Best Regards,
Houfen








 
____________________________________________________________________________________
Don't get soaked.  Take a quick peak at the forecast
with the Yahoo! Search weather shortcut.
http://tools.search.yahoo.com/shortcuts/#loc_weather