K 10
svn:author
V 7
rscheff
K 8
svn:date
V 27
2020-04-30T11:11:28.448741Z
K 7
svn:log
V 597
Introduce a lower bound of 2 MSS to TCP Cubic.

Running TCP Cubic together with ECN could end up reducing cwnd down to 1 byte, if the
receiver continously sets the ECE flag, resulting in very poor transmission speeds.

In line with RFC6582 App. B, a lower bound of 2 MSS is introduced, as well as a typecast
to prevent any potential integer overflows during intermediate calculation steps of the
adjusted cwnd.

Reported by:	Cheng Cui
Reviewed by:	tuexen (mentor)
Approved by:	tuexen (mentor)
MFC after:	2 weeks
Sponsored by:	NetApp, Inc.
Differential Revision:	https://reviews.freebsd.org/D23353

END