tech-net archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: Trimming TCP options



In article <4D1BAEC9.6090007%NGNetworks.ro@localhost>,
Mihai Chelaru  <mihai.chelaru%NGNetworks.ro@localhost> wrote:
>-=-=-=-=-=-
>
>Hi,
>
>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 ?

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

christos



Home | Main Index | Thread Index | Old Index