From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: TCP_KEEPINVTL and TCP_KEEPIDLE - Socket Keep Alives not working
Date: Tue, 30 Jun 2020 13:12:15 +0200 [thread overview]
Message-ID: <20200630111215.GE3499@calimero.vinschen.de> (raw)
In-Reply-To: <CAEF1h+UuQmXz-ntG6YMed+DKFgikJT_aJN5Hu94ZnZ8_LGxMjQ@mail.gmail.com>
On Jun 7 14:56, Cary Lewis via Cygwin wrote:
> Thanks very much for the reply - I will wait for Corinna's take on this as
> well - the patch shouldn't be too hard.
It's not that easy, but not too hard either:
- Windows 10 1709 and later actually support the TCP_KEEPIDLE,
TCP_KEEPINTVL and TCP_KEEPCNT options natively, so all is fine here.
- Older OS versions require the use of a single call
WSAIoctl(SIO_KEEPALIVE_VALS), while TCP_KEEPIDLE, TCP_KEEPINTVL and
TCP_KEEPCNT are three distinct calls, with TCP_KEEPCNT being no-op on
pre W10 1709.
> In fact the source code for curl in the lib/connect.c file has code to
> enable the winsock options, so hopefully that code could be helpful. I
But, here's the question:
Even if neither one of SIO_KEEPALIVE_VALS, TCP_KEEPIDLE, TCP_KEEPINTVL
and TCP_KEEPCNT are available, curl *still* uses SO_KEEPALIVE to enable
TCP keep-alive. Given TCP keep-alive has default settings on Windows,
too (2 hours, 1 sec, 10 times), and given SO_KEEPALIVE is supported on
Cygwin as well, why isn't that sufficient?
Keep in mind that none of the above WSAIoctl/setsockopt options are
portable, only SO_KEEPALIVE is. So why should that work on, say,
Solaris, but not on Windows?
Corinna
--
Corinna Vinschen
Cygwin Maintainer
next prev parent reply other threads:[~2020-06-30 11:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-07 13:20 Cary Lewis
2020-06-07 18:19 ` Ken Brown
2020-06-07 18:56 ` Cary Lewis
2020-06-30 11:12 ` Corinna Vinschen [this message]
2020-06-30 13:46 ` Cary Lewis
2020-06-30 16:53 ` Corinna Vinschen
2020-07-01 19:50 ` Corinna Vinschen
2020-07-02 14:52 ` Cary Lewis
2020-07-13 13:05 ` Cary Lewis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200630111215.GE3499@calimero.vinschen.de \
--to=corinna-cygwin@cygwin.com \
--cc=cygwin@cygwin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).