CVS commit: src/sys/netinet

"Kevin Bowling" <[email protected]>
Newsgroups gmane.os.netbsd.devel.cvs
Message-ID <[email protected]>
Module Name:	src
Committed By:	kbowling
Date:		Wed May 20 21:12:36 UTC 2026

Modified Files:
	src/sys/netinet: tcp_subr.c tcp_timer.h

Log Message:
tcp: set initial RTO to 1s per RFC 6298

Lower TCPTV_SRTTDFLT from 3s to 1s and adjust the t_rttvar seed in
tcp_tcpcb_template() so the pre-measurement TCP_REXMTVAL() equals
TCPTV_SRTTDFLT (was 2*TCPTV_SRTTDFLT).  Active opens and SYN|ACK
retransmits now start at 1s and back off 1, 2, 4, ... per RFC 6298
sections 2.1 and 5.5.  Post-first-sample RTO is unchanged.

Pin tcp_msl_remote_threshold to its previous numeric default (3*PR_SLOWHZ)
so the SRTTDFLT change does not move an unrelated TIME_WAIT-shortening
tunable.

This is conceptually https://reviews.freebsd.org/D18941 which we ran at a
large CDN, modified for NetBSD's stack.


To generate a diff of this commit:
cvs rdiff -u -r1.299 -r1.300 src/sys/netinet/tcp_subr.c
cvs rdiff -u -r1.30 -r1.31 src/sys/netinet/tcp_timer.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.