Messages in this thread | | | Date | Thu, 30 Aug 2012 10:59:39 -0700 | Subject | Re: [PATCH 1/1] tcp: Wrong timeout for SYN segments | From | "H.K. Jerry Chu" <> |
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On Thu, Aug 30, 2012 at 6:12 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Wed, 2012-08-29 at 10:25 -0700, H.K. Jerry Chu wrote: > >> But it probably matter slightly more for TCP Fast Open (the server >> side patch has >> been completed and will be posted soon, after I finish breaking it up >> into smaller >> pieces for ease of review purpose), when a full socket will be created with data >> passed to the app upon a valid SYN+data. Dropping a fully functioning socket >> won't be the same as dropping a request_sock unknown to the app and letting >> the other side retransmitting SYN (w/o data this time). >> >> > >> > Sure, RFC numbers are what they are, but in practice, I doubt someone >> > will really miss the extra SYNACK sent after ~32 seconds, since it would >> > matter only for the last SYN attempted. >> >> I'd slightly prefer 1 extra retry plus longer wait time just to make >> TCP Fast Open >> a little more robust (even though the app protocol is required to be >> idempotent). >> But this is not a showstopper. > > Thats very good points indeed, thanks. > > Maybe we can increase SYNACK max retrans only if the FastOpen SYN cookie > was validated. > > This way, we increase reliability without amplifying the effect of wild > SYN packets.
Ok, will use sysctl_tcp_synack_retries + 1 in tcp_fastopen_synack_timer() of my upcoming TCP Fast Open server patch (hope to submit today).
Jerry
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