Wireshark-dev: Re: [Wireshark-dev] Wireshark-dev Digest, Vol 23, Issue 11
Hi Jaap,
thanks for the pointer. I have created
a new bug report and added the diff there.
I hope it worked. Can you see my request?
Many thanks,
Philip
Hi,
Please adhere to the patch submission
policy: http://wiki.wireshark.org/SendingFilesToWireshark
That ensures things are picked
up and tracked.
Thanx,
Jaap
From: wires[email protected]
[mailto:[email protected]] On Behalf Of Philip
Frey1
Sent: 2008-Apr-04 18:23
To: [email protected]
Cc: [email protected]
Subject: Re: [Wireshark-dev] Wireshark-dev Digest, Vol 23, Issue 11
Hi Guy,
> Message: 2
> Date: Fri, 04 Apr 2008 02:17:34 -0700
> From: Guy Harris <[email protected]>
> Subject: Re: [Wireshark-dev] Share CRC32C code between MPA and iSCSI
> To: Developer support list for Wireshark <[email protected]>
> Cc: [email protected], [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Philip Frey1 wrote:
>
> > we have developed a dissector for the MPA (Marker PDU Aligned
Framing)
> > protocol which is part of the iWARP stack.
> > Since we also need to do some CRC32C calculations (same as iSCSI),
>
> ...and, it appears, SCTP.
Good catch.
> The SCTP dissector has the same CRC table; its CRC routine starts
with
> 0xFFFFFFFF - which, when byte-swapped, is unchanged - and then adds
in
> to the CRC a bunch of bytes and 0's, flips the bits in the result,
and
> then swaps the bytes. Your CRC32 routine doesn't flip the bits,
so the
> right way to combine them might be to:
>
> export the CRC32 table from crc32c.c, declaring it in
crc32.h;
>
> moving the CRC32C macro from packet-sctp.c to crc32.h;
>
> moving the CRC32C_SWAP macro from crc32c.c to crc32.h
(or see whether
> GLib 1.2.x and 2.x define something equivalent, and use that);
>
> have calculate_crc32() use the CRC32C macro:
>
> guint32 calculate_crc32(const void *buf, int len, guint32 crc)
> {
> const guint8 *p = (const guint8 *)buf;
> crc = CRC32C_SWAP(crc);
> while (len-- > 0) {
> CRC32C(crc, *p++);
> }
> return CRC32C_SWAP(crc);
> }
>
> have sctp_crc32c() use CRC32C_PRELOAD instead of ~0L.
>
> There might be some other merging that could be done.
I have implemented exactly as you suggested (assuming I understood your
suggestion
correctly). :-D
Please find attached the modified files:
(I merged everything into the crc32-files and got rid of the crc32c files)
If that is what you had in mind, then I will contribute it by sending my
diff
to the bug-list of wireshark (as suggested in the README.developer).
Cheers,
Phil_______________________________________________
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