Discussion

• We continued our discussion on the use of sockaddr_in on IPv6 sockets and mapped IPv4 addresses. As far back as stable/9, it looks like using AF_INET sockaddr's on AF_INET6 TCP sockets would not have worked correctly. tuexen@ explained the subtleties of the way SCTP handles sockaddrs for AF_INET6 sockets. markj@ will ensure his patch is correct with respect to SCTP. Otherwise, it seems like a safe change to make.
• PR 252913: tuexen@ got a tracefile and some information from Netflix. This impacts stable/12. Now that 13.0 has been released, tuexen@ will look at this in the near future.
• D23230: ECN++, rscheff@ updated the sysctl interface so sysctls are not checked in fast path. Needs review.
• D28702: Planned for main, mid March. Still in progress, waiting for 13 release. rrs@ will review.
• D29835 Fix for rescue retransmission panics when rfc_6675_pipe/sack.revised is enabled.
• Lost retransmission detection: D28931 is an idea for doing SACK loss recovery in the base stack. (Documented in an I-D.) We discussed the idea further. rscheff@ will modify code to include a sysctl to enable/disable the new behavior.
• D29515: rscheff@ committed change to use jenkins hash with random salt and allow an administrator to re-salt with a sysctl. rscheff@ will MFC to stable/13.
• tuexen@ committed support for TCP over UDP to main. He plans to MFC to stable/13. tuexen@ will do this.
  • RACK will be updated after TCP over UDP support has been committed. rrs@ will do this.
• D29411: PRR for ECN and congestion window reduction. Committed to head; waiting for MFC.
  • D29440: Do preparatory work to enable PRR for more cases. Committed to head; waiting for MFC.
  • D29441: Implement PRR for !SACK. Committed to head; waiting for MFC.
• 254725: LRO panic. Peer ACKs up to last data byte. Peer SACKs FIN - see reconstructed trace from in-core packet headers PR254725.trc. snd_una is correct, but send buffer is empty. Still no progress on reproduction. Randall suggested changing the code to wait to send FIN until there was nothing outstanding (see D29565). This change will delay the remote side recognizing session shutdown, which might impact applications which take action when a session closes. General consensus is that it would be better to find and fix the bugs.
• Follow up on the RST issue reported by NFS developer: We send a challenge ACK. Remote side sends a RST. We don't process the RST. rscheff@ proposed D29690. tuexen@ and jtl@ have a small concern that we should do more work on finding the root cause before we commit a fix. rscheff@ will debug further on a machine seeing this problem.

Next meeting: 06 May @ 1400 UTC