netdev - Re: [PATCH net-next] tcp: add tcpi_segs_in and tcpi_segs_out to tcp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 21 May 2015 13:06:00 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Yuchung Cheng <ycheng@...gle.com>
Cc:	Marcelo Ricardo Leitner <mleitner@...hat.com>,
	Eric Dumazet <edumazet@...gle.com>,
	"David S. Miller" <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>,
	Matt Mathis <mattmathis@...gle.com>,
	Craig Gallek <cgallek@...gle.com>, Martin Lau <kafai@...com>,
	Chris Rapier <rapier@....edu>
Subject: Re: [PATCH net-next] tcp: add tcpi_segs_in and tcpi_segs_out to
 tcp_info

On Thu, 2015-05-21 at 12:41 -0700, Yuchung Cheng wrote:

> It'd be nice to count SYN and SYNACKs for apps tracking the handshake stats.
> For syn-cookies we can't do much. But for the rest we can account
> req->num_retrans for SYN-ACKs sent, and perhaps track SYN received in
> request sock?

Well, this is partly because we can not guarantee the behavior that I
chose to explicitly state that we were not tracking SYNACK for passive
sessions.

Also TCP_DEFER_ACCEPT comes into play here...

If we want to handle this in a deterministic way, we would have to add
some bit to warn the application reading tcp_info that the session was
initiated after a valid syncookie was received, and that initial value
of tcp_info.tcpi_segs_{in|out} can be wrong.

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html