RFC: NFS over TLS stats

From: Rick Macklem <rick.macklem_at_gmail.com>
Date: Wed, 25 Oct 2023 02:50:22 UTC
Garrett Wollman asked me via email how a server
admin could tell what usage NFS over TLS was
happening.

I admitted that there was nothing. I have come up
with a patch that generates the following:
kern.rpctls.snd_tls_msgbytes: 21508
kern.rpctls.snd_msgbytes: 20828
kern.rpctls.snd_tls_msgcnt: 57
kern.rpctls.snd_msgcnt: 58
kern.rpctls.rcv_tls_msgbytes: 12336
kern.rpctls.rcv_msgbytes: 12072
kern.rpctls.rcv_tls_msgcnt: 57
kern.rpctls.rcv_msgcnt: 58

Basically counts of number of RPC messages
and total number of bytes those messages
result in. (Both with/without TLS.)

Does this seem reasonable or are there better
statistics that could be generated?  Obviously
any other suggestion might or might not be
practical to implement.

Thanks, rick