(Please cc me on replies - I'm subscribed nomail as this is a one-off
question.)
While reviewing the manual page bits in
https://reviews.freebsd.org/D23230, I checked tcp(4) as it stands in
14-current (using
https://www.freebsd.org/cgi/man.cgi?query=tcp&apropos=0&sektion=4&manpath=FreeBSD+14.0-current&arch=default&format=html),
and it mentions it's subject to change. (It's also very poorly
documented, perhaps as a result of the stated instability.) The history
section mentions it was brought in following Linux 2.6, and checking the
git log dates its arrival in FreeBSD to November 2004, and official
acknowledgement in documentation of its existence to January 2007. The
TCP_INFO language in tcp(4) hasn't changed since as far as I can tell.
Half of the 16 changes
https://cgit.freebsd.org/src/log/?qt=grep&q=tcp_info returns are over 12
years in the past, and of the remaining ones, after a gap of about 6.75
years, only
https://cgit.freebsd.org/src/commit/?id=5a17b6ad98c6c3fa7a7a1ab02551abfb25cc40c9
(report use of the ECN option), maybe
https://cgit.freebsd.org/src/commit/?id=f8fea0d90e04d0a1908c36080ab1cfb84dc705a2
(something related to cxgbe that may or may not change what it reports),
maybe
https://cgit.freebsd.org/src/commit/?id=7576fe761e9df400f097d4d7ce9f24340f8c4dd7
(report something related to that same driver), and probably
https://cgit.freebsd.org/src/commit/?id=61e02298cea3bee31604640e53da1567271dfa57
(report something else(?) still related to that driver) seem to change
that API, if I'm reading the code right (not a given at all). That's 1
definite change, 1 likely change, and 2 possible changes in over 5
years. So how unstable is that API, and is it time to document it now?
