* move tcp_sack_newack bits inside reno and newreno_fast_retransmit_newack
* notify ECN peer about cwnd shrink in [new]reno_slow_retransmit
Based on the patch proposed on tech-net@ on Nov 7 with minor improvments:
* adapt wmax for no-fast convergence case
* correct cbrt calculation for big window sizes (>750KB)
from Kentaro A. Kurahone, with minor adjustments by me.
the ack prediction part of the original patch was omitted because
it's a separate change. reviewed by Rui Paulo.
happen in the TCP stack, this interface calls the specified callback to
handle the situation according to the currently selected congestion
control algorithm.
A new sysctl node was created: net.inet.tcp.congctl.{available,selected}
with obvious meanings.
The old net.inet.tcp.newreno MIB was removed.
The API is discussed in tcp_congctl(9).
In the near future, it will be possible to selected a congestion control
algorithm on a per-socket basis.
Discussed on tech-net and reviewed by <yamt>.
kefren