Re: strcut casts unsigned long

[hong zhang <henryzhang62@xxxxxxxxx>]

Ratheesh,

Thanks for reply. 

But does skb->_skb_dst allocate memory any where? It is unsigned long. This is hard part for me to understand. Any explain why unsigned long
_skb_dst can be that?

---henry

--- On Fri, 8/13/10, ratheesh k <ratheesh.ksz@xxxxxxxxx> wrote:

> From: ratheesh k <ratheesh.ksz@xxxxxxxxx>
> Subject: Re: strcut casts unsigned long
> To: "hong zhang" <henryzhang62@xxxxxxxxx>
> Cc: linux-c-programming@xxxxxxxxxxxxxxx
> Date: Friday, August 13, 2010, 1:44 AM
> On Fri, Aug 13, 2010 at 7:47 AM, hong
> zhang <henryzhang62@xxxxxxxxx>
> wrote:
> > List,
> >
> > I have C question on skbuff.h.
> > skb->_skb_dst is defined as unsigned long and
> dst_entry is struct.
> >
> > Why strct dst_entry casts unsigned long
> skb->_skb_dst?
> >
> > See below
> >
> > static inline struct dst_entry *skb_dst(const struct
> sk_buff *skb)
> > {
> >        return (struct dst_entry
> *)skb->_skb_dst;
> > }
> >
> > Appreciate any answer!
> >
> > --henry
> 
> skb->_skb_dst can be a pointer to both destination cache
> or  routing
> table . We could type cast to any of those .
> 
> -Ratheesh
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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