Date: Tue, 29 Dec 2015 11:16:38 -0800 From: Chris Stankevitz <chris@stankevitz.com> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: getsockopt(SO_SNDBUF) and openssh/HPN Message-ID: <5682DC16.9030504@stankevitz.com>
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Hello, Please identify any false statements (particularly statement 7 which accuses FreeBSD 10.1 of having a bug): 1. openssh limits the size of "the outgoing buffer" to 65KB 2. (1) limits bandwidth on high BDP links. 3. FreeBSD 10.1 supplied openssh/HPN tries to fix (2) by increasing the size of "the outgoing buffer" to match the SO_SNDBUF capacity 4. openssh/HPN accomplishes (3) by periodically calling getsockopt(SO_SNDBUF) 5. In FreeBSD 10.1, getsockopt(SO_SNDBUF) does not return the value set by setsockopt(SO_SNDBUF). Instead it reports the high watermark of the outgoing buffer. 6. (3) does nothing because of (4) and (5) 7. There is a bug in FreeBSD 10.1 networking or FreeBSD 10.1 supplied openssh/HPN: 7a. FreeBSD bug: getsockopt(SO_SNDBUF) does not return value set by setsockopt(SO_SNDBUF) 7b. openssh/HPN bug: do not use getsockopt(SO_SNDBUF) to get the value set by setsockopt(SO_SNDBUF) -- use something else Original thread from August 2015: https://www.mail-archive.com/freebsd-net@freebsd.org/msg49793.html Thank you, Chris
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