[Winpcap-users] Winpcap in Intanium machine

[Guy Harris]

On Oct 10, 2009, at 9:11 AM, Gianluca Varenni wrote:

> 2. when we access the packet contents for filtering, the header  
> fields are
> inevitably misaligned. In that case the only solution would be using  
> macros
> when reading the header fields from the packets to avoid  
> misalignment errors
> on architectures like Itanium

You mean macros such as

#define EXTRACT_SHORT(p)\
                 ((((u_short)(((u_char*)p)[0])) << 8) |\
                  (((u_short)(((u_char*)p)[1])) << 0))

and

#define EXTRACT_LONG(p)\
                 ((((u_int32)(((u_char*)p)[0])) << 24) |\
                  (((u_int32)(((u_char*)p)[1])) << 16) |\
                  (((u_int32)(((u_char*)p)[2])) << 8 ) |\
                  (((u_int32)(((u_char*)p)[3])) << 0 ))

Unless I'm missing something, or you mean something other than BPF  
filtering by "filtering", WinPcap's BPF interpreter *already* uses  
macros when reading data from packets - it's done that for ages (BPF  
dates back to about 1993; it appears they did the development on a  
SPARCstation, and SPARC processors don't do unaligned accesses).