[Bug 206716] HPN-SSH: getsockopt(SO_SNDBUF) returns high watermark, not setsockopt(SO_SNDBUF)

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=206716

            Bug ID: 206716
           Summary: HPN-SSH: getsockopt(SO_SNDBUF) returns high watermark,
                    not setsockopt(SO_SNDBUF)
           Product: Base System
           Version: 10.1-RELEASE
          Hardware: amd64
                OS: Any
            Status: New
          Severity: Affects Only Me
          Priority: ---
         Component: bin
          Assignee: freebsd-bugs at FreeBSD.org
          Reporter: chris-freebsd-bugs at stankevitz.com
                CC: freebsd-amd64 at FreeBSD.org
                CC: freebsd-amd64 at FreeBSD.org

getsockopt(SO_SNDBUF) does not return the value set by getsockopt(SO_SNDBUF).

HPN-SSH would like to determine the value set by setsockopt(SO_SNDBUF) so that
it can fill it up.  This helps to use more bandwidth on a high BDP link.

HPN-SSH  tries to determine this value by periodically calling
getsockopt(SO_SNDBUF) at [1]. However, on FreeBSD, getsockopt(SO_SNDBUF) does
not return the value set by setsockopt(SO_SNDBUF).  Rather it returns the "high
watermark".

The net result is that on high BDP links, HPN-SSH does nothing to increase
bytes-in-flight.

[1] /usr/src/crypto/openssh/roaming_common.c line 59 in get_snd_buf_size:
getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &optval, &optvallen)

-- 
You are receiving this mail because:
You are on the CC list for the bug.