Isson on relationship between socket and sock of a packet?

Isson on relationship between socket and sock of a packet?

[Park Lee]

Hi,
  I'm a newbie on Linux IP network, there are some
problems that confuse me a lot. I sincerely need you
help.
  In Linux IP network, when a packet is going to be
sent out. Would you please tell me which one of the
following items is right for the packet (Let's suppose
struct sock *sk; struct socket *skt):
  1), The packet has a sock (i.e. sk!=NULL), but
doesn't has a socket (i.e. skt=NULL) corresponding to
the packet?
  2), The packet has a socket (i.e. skt!=NULL), but
doesn't has a sock (i.e. sk=NULL) corresponding to the
packet?
  3), The packet doesn't has the both (i.e. sk=NULL
and skt=NULL)?
  
  And, If some of them are right, Would you please
also give me some examples of them?

  Thank you very much.


=====
Best Regards,
Park Lee


		
__________________________________ 
Do you Yahoo!? 
Meet the all-new My Yahoo! - Try it today! 
http://my.yahoo.com