Not able to access the union variables

[hari kumar]

Hi,
   I am not able to access an union variables in the following header
file (linux/skbuff.h) .
  given below are the details of the union variable

 union
        {
                struct tcphdr   *th;
                struct udphdr   *uh;
                struct icmphdr  *icmph;
                struct igmphdr  *igmph;
                struct iphdr    *ipiph;
                struct spxhdr   *spxh;
                unsigned char   *raw;
        } h;
 filename : linux /skbuff.h
 structure name where the union is declared : struct sk_buff

     I am not able to access the th/uh/icmph etc pointer objects from
the above union.
     I am working with this module in the KERNEL SPACE.
     It would be of great help to me, if you can give  me some
information on this regard. Any information or thoughts are welcome on
the same.

Thanks
Regards
Hari