Hangout 23 May 2019
Old Business
- IPv6 Fragment reviews which need testing:
- IPv6 modernization project: Wiki Page
- Julius proposed importing OpenBSD fragmentation regression test cases (see D17376). thj@ is working on it.
- Stalled; switched to fragment tests; will restart once basic fragment tests (next item) are imported.
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- Just updated. Tom will mercilessly harass jtl@ until he reviews it.
- IP6 IDs (and IP IDs, maybe?): may use an insecure algorithm. Ideally, switch to some sort of per-host-pair hash?
- What do OpenBSD/NetBSD do?
- tuexen: OpenBSD does skip32. We use a linear congruential algorithm. NetBSD uses the same algorithm we do. jtl@ says he found an academic paper (analyzing ID-generation functions in another context) which says our function is insecure, but he needs to re-find it.
- Perhaps, a small cache would be sufficient?
- RFC 7739 provides three different options to consider.
- jtl@ to send patch to Richard for burst mitigation in the default stack. An idea is in D19047.
- Still need to do.
- D18811: standardize on snd_recover (vs. sack_newdata). Reviewer: tuexen@, lstewart@.
- @tuexen will review again.
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- Helps when HW LRO is enabled.
- Also, this enables a PRR patch (based on Lars work). D18892. Needs review.
- CUBIC: Only invoking NewReno after_idle, not resetting ssthreash, not resetting epoch time: D18982, D18954, and D19118. Including another issue, this will be discussed at the IETF.
- lstewart@ is the best person to review this.
- D19000 deal with a bug that the 1 byte occupied in the sequence number space by SYN segments results in a cwnd increase when acked. This bug exists only on the server side. tuexen@ and Richard are working on it.
- Richard is working on burst mitigation. An initial version (WIP) is available as D19047.
- tun/tap interfaces: should we see outgoing packets in tcpdump?
- Currently inconsistent. In general, yes, these should be visible.
- There was a re-write of tun/tap interfaces in the meantime. tuexen@ will re-evaluate.
New Things
- Review BSDCan Dev Summit Working Group notes Items for us:
- Revisit how we maintain multiple TCP stacks
- Revisit CC API
- Talk about further network modularity (as requested by Juniper)
- hps@ asks about D19622.
- Feedback: because fragments are not tied to arrival interface, it doesn't make sense to drop fragments.
- hps@ asks about D20051.
- Waiting for bz@.
- hps@ asks about D20080.
- No feedback on the call; participants will need to review.
- hps@ asks about D20109.
- mmacy@ is opposed to extending the epoch API this way. hps@ is looking for more opinions and/or ideas. Participants will need to review.
- tuexen@ asks about D20372.
- Needs review. Fixes bug which keeps RACK from working correctly in some cases.
- tuexen@ asks about D20374.
- jtl@ approved.
- tuexen@ asks about whether he should backport the timestamp change to protect system time to stable/11 and/or stable/12.
- jtl@ explained the policy (as he understood it) and the variety of opinions on when something should be backported. tuexen@ will evaluate and use his best judgment.
Next Meeting
Scheduled for 6 June, 14:00 UTC.