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Re: Comments on ESP and AH IPSEC drafts.
On Thu, 26 Sep 1996, Rob Adams wrote:
> ESP Draft (draft-ipsec-esp-des-md5-03.txt Sept 96):
>
> Section 2.5: Padding.
>
> I would like to suggest placing the Payload Type, Pad Length and padding
> fields before the payload data. Stop laughing. After having implemented
> this, I can say that it would be a heck of a lot more efficient and
> therefore, perform better, if I didn't have to walk an MBUF chain twice to
> remove padding. You have to do this twice because you have to go to the
> end first to get the length of the padding. Since the padding could be
> spread out of a variable number of buffers behind you, you have to start at
> the head again and walk down until you find the buffer containing
> packet[length-pad], and free from there. Chopping the data off the head of
> the buffer chain would save this walk and some hairy math to crop the right
> size of data off the end.
In Net/3 code, the padding can span at most 2 mbufs, so you only need to keep track of
the current and previous mbufs.
Norm
Norman Shulman Border Network Technologies Inc.
Software Engineer Tel 1 416 368 7157 ext 304
norm@border.com Fax 1 416 368 7178
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