TCP send and recv buffer scaling.

Send buffer is scaled by not accounting unacknowledged on the wire
data against the buffer limit. Receive buffer scaling is done similar
to FreeBSD -- measure the delay * bandwith product and base the
buffer on that. The problem is that our RTT measurment is coarse
so it overshoots on low delay links. This does not matter that much
since the recvbuffer is almost always empty.
Add a back pressure mechanism to control the amount of memory
assigned to socketbuffers that kicks in when 80% of the cluster
pool is used.
Increases the download speed from 300kB/s to 4.4MB/s on ftp.eu.openbsd.org.

Based on work by markus@ and djm@.

OK dlg@, henning@, put it in deraadt@

0 files changed, 0 insertions, 0 deletions