Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
No functional change intended.
timestamp related stack variables to reference ms directly instead of ticks.
The h_ertt(4) Khelp module relies on TCP timestamp information in order to
calculate its enhanced RTT estimates, but was not updated as part of r231767.
Consequently, h_ertt has not been calculating correct RTT estimates since
r231767 was comitted, which in turn broke all delay-based congestion control
algorithms because they rely on the h_ertt RTT estimates.
Fix the breakage by switching h_ertt to use tcp_ts_getticks() in place of all
previous uses of the ticks variable. This ensures all timestamp related
variables in h_ertt use the same units as the TCP stack and therefore results in
meaningful comparisons and RTT estimate calculations.
Reported & tested by: Naeem Khademi (naeemk at ifi uio no)
Discussed with: bz
MFC after: 3 days
Khelp/Hhook KPIs to hook into the TCP stack and maintain a per-connection, low
noise estimate of the instantaneous RTT. ERTT's implementation is robust even in
the face of delayed acknowledgements and/or TSO being in use for a connection.
A high quality, low noise RTT estimate is a requirement for applications such as
delay-based congestion control, for which we will be importing some algorithm
implementations shortly.
In collaboration with: David Hayes <dahayes at swin edu au> and
Grenville Armitage <garmitage at swin edu au>
Sponsored by: FreeBSD Foundation
Reviewed by: bz and others along the way
MFC after: 3 months
