12Sep2019 [FreeBSD WIKI]

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===== Old Things =====
  * Discussion about [[https://reviews.freebsd.org/D19622|D19622]]. hps@ is waiting for bz@ to let him know whether he is 
  * Discussion about [[https://reviews.freebsd.org/D16851|D16851]]. Broken into 4 reviews; needs some additional test cases; is close.
  * Discussion about Richard's review to do some cleanup in preparation for RFC 6675 support: [[https://reviews.freebsd.org/D18624|D18624]]. jtl@ has an open question. tuexen@ will look into it. Looks good to jtl@ and tuexen@ on the surface, but tuexen@ still has not been able to Still pending.
  * Discussion about thj@'s [[https://datatracker.ietf.org/meeting/105/materials/slides-105-6man-sessa-change-status-of-rfc-2675-to-historic-00|presentation]] at IETF (actually delivered by Gorry on his behalf). Response from IETF was mixed, but it was clear that this is an optional feature we are free to drop. thj@ has a review to drop this: [[https://reviews.freebsd.org/D19960|D19960]]. Tom to email %%FreeBSD%% lists to advertise review. tuexen@ reports on a fun fact about SCTP and jumbograms. :-)
  * Discussion about TCB size/organization. bz@ is looking into ways to automate cacheline usage analysis with a goal to enabling automatic structure organization optimization. No update.

===== New Things =====
  * Richard reports an interesting case of possible data corruption with fragmented TCP segments. It needs more information.
  * tuexen@ proposes replacing MD5 with SIP hash for ISNs and time stamps. It has better performance, and we think it has sufficient security for this purpose. tuexen@ to notify security team in case they have concerns. [[https://reviews.freebsd.org/D21616|D21616]]
  * tuexen@ asks about how we should handle the case where an application specifies an infeasible size of IPv6 options. syzkaller has detected a panic with this. jtl@ suggests that we should add destination options to the fragmentable portion, if they aren't already. thj@ says we should reject sending packets where the ULP header is not in the first fragment. This may not be detectable until connect time, but you can return EMSGSIZE then.
  * jtl@ asks for feedback on a proposal to stop adding new syn cache entries when the syn cache hash bucket is full. tuexen@ suggests we stop all syn cache processing (and fallback to cookies only) when under attack. tuexen@ suggests a heuristic of one bucket overflowed. This should be accompanied by a log entry so the administrator can take appropriate action (whether investigating the attack, increasing bucket sizes for normal traffic levels, or ignoring the message).
  * thj@ reports that dummynet doesn't work in jails. tuexen@ gave some advice. thj@ will follow up with bz@.
  * New congestion window validation: Richard explains why it would be helpful. thj@ suggests pacing will help here. thj@ will also ask Gorry for feedback.

===== Next Meeting =====
Next meeting is 26 Sep 2019 @ 1400 UTC.