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Re: Trimming TCP options

In article <>,
Mihai Chelaru  <> wrote:
>I'd like to drop paddings for wscale, sack, tcpsig and timestamps in syn
>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 ?

If the options happened to be properly aligned, you don't send TCPOPT_EOL


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