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Re: Trimming TCP options

Mihai Chelaru <> writes:

> I'd like to drop paddings for wscale, sack, tcpsig and timestamps in syn
> options.
> Currently our TCP code is padding every option to 32bit, although this
> is not required by RFC793 or other standards except a special case
> for timestamps as far as I know. For example on NetBSD 5.1(RC2) at a
> simple telnet we end up sending SYNs with 4 consecutive nop options and
> for 4 options we also send 5 nops:
> <mss 1300,nop,wscale 3,sackOK,nop,nop,nop,nop,timestamp 1 0>
> After this change, options will look like:
> <mss 1300,wscale 3,sackOK,timestamp 1 0,eol>
> Also, as an immediate result TCP_SIGNATURE started to work instead on
> panicing kernel after overflowing the 40 bytes opt buffer.
> Patch is attached, opinions ?

Could you explain

  how long you've been running this

  the kinds of peers it's been tested against

  how other implementations behave?  (Specifically, does this make us
  like the rest, or different?)

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